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  • 1970-1974  (564)
  • 1965-1969  (278)
  • 1920-1924
  • Computational Chemistry and Molecular Modeling  (654)
  • Electron Microscopy
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Year
  • 1
    ISSN: 1434-4726
    Keywords: Spiral ganglion and Organ of Corti ; Electron Microscopy ; Influence of Different Fixatives and Fixation Methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Das Ganglion spirale und Cortische Organ des Meerschweinchens wurden nach Osmium- und kombinierter Glutaraldehyd-Osmiumfixation sowie Anwendung verschiedener Fixationsmethoden elektronenmikroskopisch untersucht. Die Strukturen des Cortischen Organs wurden hierbei nicht wesentlich beeinflußt. Am Ganglion spirale ergaben sich Unterschiede im Aufbau der Myelinhüllen der Ganglienzellen. Es wird diskutiert, daß es sich beim semikompakten Myelin um ein Artefakt der Osmiumfixation handelt und daß Glutaraldehyd den Aufbau der Myelinhüllen im Bereich der Spiralganglienzellen naturgetreuer wiedergibt als Osmium.
    Notes: Summary We have been examining with the electron microscope the spiral ganglion and the organ of corti in guinea pigs, using osmium and a combined glutaraldehyde-osmiumfixation together with various fixation techniques. The structures of the organ of corti were not considerably effected. Differences in the structure of the myelin sheets of ganglion cells were found in the spiral ganglion. Presumably the semicompact myelin represents an artefakt after osmium-fixation, glutaraldehyde being able to demonstrate clearer the structure of the myelin sheets on spiral ganglion cells compared to osmium.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 16 (1974), S. 109-127 
    ISSN: 1432-0827
    Keywords: Dentinogenesis ; Diphosphonates ; Calcification ; Collagen ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The effects of high doses of ethylene-1-hydroxy-1,1-diphosphonate (EHDP) were investigated at the light microscopic and subcellular level. The administration of EHDP at a concentration of 7.5–10 mg P/kg body weight/day over a short period of time resulted in complete inhibition of crystal formation in predentin and pre-enamel. An increased predentin width was observed and within newly-formed predentin areas the formation ofcollagen fibrils was grossly disturbed. In addition, fine precipitates appeared in the ground substance. The presence of unusual thread-like elements within specific bodies in the cytoplasm of the odontoblastic processes may be indicative of an interference by EHDP in e.g. the synthesis of precollagen. The possibility of an inhibition by EHDP of the extracellular aggregation of collagen molecules is also discussed. EHDP further inhibited crystal formation within dentinal globules. Functioning ameloblasts were grossly affected in EHDP-treated rats, and it is suggested that this is related to an inhibition of crystal formation in pre-enamel.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 364 (1974), S. 111-127 
    ISSN: 1432-2307
    Keywords: Electron Microscopy ; Coronary Arteries ; Atherosclerosis ; Aging ; Smooth Muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The coronary arteries were studied by electron microscopy in normal rats weighing 65 to 535 gm; fixation was accomplished by perfusion for 20 min at 110–130 mm Hg. In rats of all ages (but especially in the oldest) the arterial wall contained deposits of abnormal intercellular material, consisting of granules, vesicles, myelin figures and other debris. These deposits were present in the intima and media, but rare in the adventitia; there was suggestive evidence that medial cells phagocytized some of the material. The adventitia was characterized by 1–4 layers of cells with extremely thin protoplasmic expansions wrapped around the vessel (“veil cells”) and containing lysosome-like bodies as well as phagosomes. These findings, taken as a whole, suggest the following sequence of events. During normal life, the media produces cellular debris, by cell death as well as by fragmentation of cellular processes; part of these debris are phagocytized by smooth muscle cells, part diffuse outward to the adventitia where they are taken up by specialized cells (the “veil cells”). However, due to relative inadequacy of phagocytosis in the media, the debris continue to accumulate and form intercellular deposits that increase with age. It is possible that this natural phenomenon may by itself set a maximal limit to the life-span of the arterial wall.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 363 (1974), S. 249-258 
    ISSN: 1432-2307
    Keywords: Hypertensin (Angiotensin) ; Catecholamins ; So-Called Epinephrine Myocarditis ; Rat Heart ; Optical Microscopy ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Pathomorpliological comparative studies on structural damage to rat cardiac muscle following administration of hypertensin and arterenol, with and without pretreatment with reserpine to empty the catecholamine reserves were performed. The question is whether and to what degree angiotensin induced cardiac damage, which is viewed microscopically as the so-called epinephrine myocarditis, can be regarded as an indirect catecholamine effect. The following could be deduced: 1. Hypertensin causes a damage pattern similar to that of arterenol as seen under the light microscope and corresponds to the so-called epinephrine myocarditis. 2. The electron microscope demonstrates definite differences in the pattern of damage to the myocardium: hypertensin affects primarily the mitochondria, while arterenol affects the myofibrils. 3. Hypertensin and arterenol damage mainly the subendocardial tissue of the left heart: hypertensin affects more the region of the base of the left ventricle, arterenol more the region of the left ventricle apex. 4. Pretreatment with reserpine blocks the damaging effects of hypertensin in the rat heart for 12 hours. After 24 hours the full picture of the damage pattern has reappeared. Arterenol is lethal to animals pretreated with reserpine. 5. The pathogenesis of the damaging effects of hypertensin on rat cardiac muscle is discussed.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 27 (1974), S. 201-213 
    ISSN: 1432-0533
    Keywords: Infantile Neuroaxonal Dystrophy ; Spheroids ; Perikaryon ; Electron Microscopy ; Membranous Profiles ; Dense Bodies ; Protein Syntheses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electron microscopic findings of a cortical biopsy from a four-year-old child suffering from muscular weakness and psychomotor retardation are presented. Morphological evidence obtained in this study suggests a unique pathogenetic mechanism underlying INAD. The spheroids appear to be caused by an accumulation of a macromolecular substance synthesized in the neuron and transported to the nerve endings. The abnormal substance initially takes the form of an amorphous material, it eventually aggregates into highly characteristic angulated membranous profiles. The selective involvement of the nerve endings, synapses and motor end plates in this disease suggests a derangement of the metabolic pathway in the synthesis or packaging of the neurotransmitters or their receptors.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 30 (1974), S. 271-276 
    ISSN: 1432-0533
    Keywords: Intracranial Teratoma ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A massive congenital benign teratoma grossly replacing the cerebral hemispheres has been examined by light and electron microscopy. The tumor contained tissues derived from all three germ layers. The cerebellum showed morphological features suggesting a state of maturation equivalent to that of 20 to 25 weeks of gestation. The tumor is discussed in the light of present theories on the pathogenesis of teratomas.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 27 (1974), S. 43-53 
    ISSN: 1432-0533
    Keywords: Oncocytes ; Adenohypophysis ; Pituitary Adenoma ; Secretory Granules ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A light and electron microscopic study was undertaken on 3 surgically removed non-tumorous adenohypophyses and 16 pituitary adenomas. Numerous oncocytes have been found in 2 non-tumorous adenohypophyses and in 6 pituitary adenomas including 1 chromophobe adenoma which was composed almost exclusively of oncocytes. Thus, it seems that the occurrence of oncocytes in the anterior pituitary cannot be considered a rare finding. The distinctive feature of oncocytes is the abundance of mitochondria in their cytoplasm. This alteration can be so extensive that the entire cytoplasm is filled with mitochondria leaving only a small area for the remaining cytoplasmic organelles. Oncocytes arise from adenohypophysial cells. This transformation is gradual and is not restricted to one particular cell type. In the early phases of development of oncocytes the secretory granules are well preserved. Thus, hormone secretion is presumably maintained. It seems conceivable, however, that in the more advanced phases of evolution of oncocytes, when the secretory granules decrease in number, hormone production is diminished or stopped. Further investigations are, however, required to elucidate in detail the functional activity of oncocytes. It remains to be established whether mitochondrial accumulation is principally due to increased formation or delayed breakdown. As some mitochondria show signs indicating division it appears that multiplication of mitochondria is the underlying mechanism resulting in their significant increase. However, the possibility cannot be excluded that the life span of mitochondria is prolonged and mitochondrial longevity plays an important role in causing transformation of adenohypophysiocytes into oncocytes.
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  • 8
    ISSN: 1432-0533
    Keywords: Progressive Multifocal Leukoencephalopathy ; Hirano Bodies ; Papova Virus ; Paramyxovirus-like ; Nuclear Bodies ; Electron Microscopy ; Neurofibrillary Tangles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have identified three structures that have not previously been reported in electron microscopic examinations of brain from patients with PML: 1. coiled nuclear bodies that may possibly represent tubular paramyxovirus nucleocapsids, 2. Hirano bodies and 3. Neurofibrillary tangles. The paramyxovirus-like material is interesting in view of reports of a transition between nuclear bodies and tubular paramyxovirus nucleocapsids and because of a possible interaction between syncytiogenic paramyxoviruses and Papova viruses in the pathogenesis of SSPE and PML. A study of the Hirano bodies in this case, taken in conjunction with the findings of others leads us to believe that these structures are formed from an overgrowth of neurofilaments. The presence of tangled masses of neurofilaments in the processes of neurons also seen in the present case is consistent with this hypothesis.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 28 (1974), S. 93-103 
    ISSN: 1432-0533
    Keywords: Hexachlorophene Intoxication ; Toxic Encephalopathy ; Optic Nerve Necrosis ; Cerebral Edema ; Status Spongiosus ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This is the first report of neuropathologic findings following oral ingestion of hexachlorophene in the human. The patient was a 7 year old boy who accidentally ingested 45 ml (approx.) of pHisoHex (hexachlorophene).Toxic reactions included nausea, vomiting, anorexia, diarrhea, decrease in visual acuity, blurred vision blindness, somnolence and disorientation. He developed cardiac arrhythmia, fever, isoelectric EEG and finally respiratory and cardiac arrest 61 h after admission. Autopsy findings showed interstitial myocarditis, pneumonitis and acute bronchiolitis. The brain was edematous. Light microscopy revealed mild diffuse vacuolization of white matter, occasional neuronal degeneration, most prominent on deepest layers of the visual cortex. Disintegration of myelin sheaths and necrosis of axon cylinders were present throughoutoptic pathways. Electron microscopy revealed large, empty extracellular and intramyelinic spaces formed by splitting and separation of the myelin lamellae. These changes are known to occur in experimental animals intoxicated with hexachlorophene, triethyltin, isonicotinic acid hydrazide and cuprizone. However, with respect to hexachlorophene, the localization of lesions to be optic pathways appears to be dependent upon an oral route of administration.
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  • 10
    ISSN: 1432-0533
    Keywords: Neuroaxonal Dystrophy ; Infantile Autonomi Nervous System ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The autonomic nervous system is studied by electron microscopy for the first time in two siblings born of North African consanguineous parents and affected by infantile neuroaxonal dystrophy. The changes already reported in dystrophic axons of the central and peripheral nervous system, are seen in the myenteric plexus of rectum mucosa. The authors stress the diffuse involvement of the nervous tissue in this degenerative disorder of still unknown nature.
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  • 11
    ISSN: 1432-0533
    Keywords: Craniopharyngioma ; Tissue Culture ; Electron Microscopy ; Enzyme Histochemistry ; Keratine ; Enamel ; Rosenthal Fibers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electron optical and enzyme histochemical investigations carried out on four craniopharyngiomas and their tissue cultures demonstrated that the tumour elements are keratinizing epithelial cells, plenty of tonofilaments, glycogen granules, mitochondria and desmosomes. Their ultrastructural and histochemical characteristics are the same in every part of the tumour (solid; cystic; “adamantinoma-like”). In the keratinizing cells, the reactions for non-specific esterases were high positive. The ultrastructural characteristics of the tumour cells grownin vitro are the same as thosein situ; the cells remain attached to one another by desmosomes and retain their capacity to produce keratine. This therefore seems to be a primary characteristic of the tumour cells and not a secondary dysmetabolic disturbance. Calcium was found onlyin situ. That the tumour cells may produce enamelin situ seems to be possible, but it could not be confirmed with certainty. The glial proliferation which is always presentin situ, is reactive and not neoplastic; thein vitro new built cell colonies consist only of epithelial elements.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 29 (1974), S. 45-55 
    ISSN: 1432-0533
    Keywords: Experimental Neural Tumours ; Ethylnitrosourea ; Electron Microscopy ; Lysosomes ; Acid Phosphatase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A single intravenous injection of 30 mg of N-ethyl-N-nitrosourea per kg of body weight was administered to pregnant BD-IX rats on the 15th day of gestation. The neural tumours which developed in 97.5% of the offspring were gliomas and schwannomas. The demonstration of acid phosphatase in the neoplastic and reacting cells of these tumours was carried out at fine structural level. The enzyme activity was localised in lysosomes and in the innermost cisternae of the Golgi complexes. High acid phosphatase activity was related not only to degeneration, necrosis and phagocytosis but also to cellular differentiation and anaplasia.
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  • 13
    ISSN: 1432-0533
    Keywords: Steele-Richardson-Olszewski Syndrome ; Progressive Supranuclear Palsy ; Neurofibrillary Tangles ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The neurofibrillary tangles found in the neurons of a case of Steele-Richardson-Olszewski syndrome were studied by electron microscopy. Both the flame-shaped and globose type of tangles were present. The neurofibrillary tangles were composed of bundles of straight tubules measuring approximately 150 Å in diameter. This ultrastructural appearance of the tangles in Steele-Richardson-Olszewski syndrome is different from the appearance of tangles found in other neurological disorders and is probably indicative of intraneuronal accumulation of a new type of fibrous protein.
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  • 14
    ISSN: 1432-0533
    Keywords: Polyneuropathy Associated with Adie's Syndrome ; Sural Nerve ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The sural nerve of a woman of 35 with chronic polyneuropathy and Adie's syndrome was examined by electron microscopy. Myelinated nerve fibres were absent and there was marked reduction in the number of unmyelinated fibres. Onion bulb formation was not observed. Collagen fibres occupied the intercellular spaces.
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  • 15
    ISSN: 1432-0533
    Keywords: Experimental Neural Tumours ; Ethylnitrosourea ; Electron Microscopy ; Thiamine Pyrophosphatase ; Adenosine Triphosphatase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structural localisation of thiamine pyrophosphatase and adenosine triphosphatase was carried out in gliomas and schwannomas induced transplacentally by N-ethyl-N-nitrosourea. The activity of thiamine pyrophosphatase was observed in the Golgi complexes and appeared to be directly related to cellular differentiation and reactive changes. The Mg2+-dependent adenosine triphosphatase was localised at the cell membrane, in the pinocytotic vesicles of various cells and in the basement membrane of some capillaries. This enzyme, showing high activity in differentiated cells, indicated the activity of membrane-bound cellular transport.
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 29 (1974), S. 211-222 
    ISSN: 1432-0533
    Keywords: Experimental Gliomas ; Ethylnitrosourea ; Electron Microscopy ; Virus-like Particles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two unusual, intracytoplasmic structures, resembling viruses, are described in experimental gliomas which were induced transplacentally on the 15th day of gestation in BD-IX rats by a single intravenous injection of 30 mg of N-ethyl-N-nitrosourea per kg of body weight. These structures are tubules within the lumen of the endoplasmic reticulum and large coated vesicles in the Golgi region. The tubules are of indeterminate length and have inner and outer walls of 9–11 nm and 20–22 nm respectively. The large coated vesicles are 80–90 nm in diameter and their outer surface is covered by regular, equidistant spikes of 12–15 nm in length. The vesicles are closely related to the Golgi complexes, from which they appear to originate. The intracisternal tubules and large coated vesicles share certain morphological features both with viruses and with normal cell organelles. The origin and significance of these structures are discussed.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 30 (1974), S. 315-328 
    ISSN: 1432-0533
    Keywords: Human Adenovirus Type 12 ; Sprague-Dawley Rats ; Intracerebral Inoculation ; Medulloepitheliomatous Neoplasm ; Giant Tumor Cells ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Solid medullary brain and spinal cord neoplasms developed in all 10 offspring of an outbred Sprague-Dawley rat, between 37 and 99 days after a single postnatal (within 24 hrs) inoculation of 0.05 ml of human adenovirus type 12, 103.5–104.5 TCID50 HeLa cells/0.1 ml in the left frontal lobe. Seven rats developed multicentric neoplasms in both hemispheres and in peri-aqueductal areas of the brain stem, one of which was associated with an incipient spinal cord tumor in the sacral segment. One rat developed a solid tumor involving the right parieto-occipital region. The remaining two cases were solid spinal cord tumors arising from the dorsal half of the thoracolumbar segments. The remarkably uniform microscopic appearance was designated as a counterpart of human embryonic neuronal neoplasms. Characteristic neuronal and multinucleated giant cells emerged throughout the tumor tissue with argentaffine, neurofibril-like cytoplasmic expansions and a unique cilium (a 9+0 pattern of tubules) associated with a pair of centrioles. This cilium morphology was also a hallmark of the majority of tumor cells that formed characteristic pseudorosettes. The occasional emergence of two sets of cilia and centrioles in monstrous cells suggested probable modes of cytogenesis in relation to cessation of abnormal cell division.
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 30 (1974), S. 33-41 
    ISSN: 1432-0533
    Keywords: Organic Mercury Compound ; Late Pathological Changes in Peripheral Nerves ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Wistar strain of male rats of 100–110 g were used, 5 for an experimental and 5 for control group. 1 mg of organic mercury (methyl methylmercuric sulfide: CH3HgSCH3) was given by mouth each day for 10 days (total dose 9–10 mg) to the experimental group. 600 days afterwards the experimental and control rats were killed. Only the peripheral nerves showed changes, small myelinated nerve fibres with thick myelin sheaths in groups. Around these fibres occurred extremely small myelinated nerve fibres and isolated large unmyelinated fibres, and appeared to be regenerated fibres. Destruction of myelin sheaths and cavity formation in the axons were observed in these fibres. The changes in the axons were remarkable at the nodes of Ranvier.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 30 (1974), S. 11-24 
    ISSN: 1432-0533
    Keywords: Ataxia ; Rabbit ; Degeneration ; Cochlear Nuclei ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This hereditary animal ataxia is selective in its sites of involvement within the nervous system, which include principally the central cerebellar, vestibular and cochlear nuclei. Ultrastructural detail has been described for central cerebellar and vestibular nuclei. Herein the cochlear complex of 18 rabbits with this ataxic condition (ax/ax from the strain AX of the Jackson Laboratory) have been examined. The gene is a lethal one, but the animals were used before they became moribund and between 7 and 57 days after the onset of symptoms. By light microscopy nine cell types (Osen, 1969a, b; 1970) have been identified in the cochlear nuclei of the cat. That distribution can also be identified in electron micrographs of rabbit cochlear nuclei, providing there is a singular opportunity to compare cellular vulnerabilities within the ataxic condition, and establish the principal features of associated neuropil alterations. The cochlear nuclei, cerebellar cortex and central nuclei, and the vestibular nuclei, arise from the ependyma of the rhombic lip of the fourth ventricle, making them close allies in their genetic origins. Pathological alterations were evident in scattered neurons from all nuclear sources by 7–15 days following symptom onset. At 15 days the number of altered neurons evident in electronmicrographs had increased markedly, cells becoming involved at a more rapid pace than those already affected could be removed. Much glycogen is evident from 7 days onwards in both neuropil and neurons. It occurs in considerable amounts in astrocytic processes and less abundantly in endbulbs and somata. By 20 to 25 days spongioform changes in neuropil are prominent, and thereafter the extracellular spaces coalesce to produce a lacunar appearance showing little glycogen. It would appear, therefore, that all neuron types, the endbulbs, and the astrocytic processes are markedly involved simultaneously in the spongioform transformation which features this type of ataxia. Involvement of cochlear nuclei only differs in pathological detail from that found at the other involved sites, and the differences seen relate principally to the architectonics of the nuclei, including size and density of the packing of contained elements.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 30 (1974), S. 155-173 
    ISSN: 1432-0533
    Keywords: GM1-Gangliosidosis ; Glycoproteins ; β-Galactosidase ; Lysosomal Disease ; Electron Microscopy ; Genetics of GM1-Gangliosidosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Post-mortem studies on a 6-year old boy with GM1-gangliosidosis, Type II revealed no evidence of accumulation of residual bodies nor of gangliosides or glycoproteins in liver and spleen. In brain tissue the ganglioside GM1 accounted for 70% of the ganglioside fraction and ganglioside-NANA was increased 3.6 fold over controls. In addition, the brain tissue contained large amounts of glycoprotein, glycoprotein derived galactose being increased 2.5 times. The neuronal accumulation of tertiary lysosomes exhibited a characteristic distributional pattern: in general the large neuronal perikarya were more consistently involved with the exception of the motor cells of the cranial nerve nuclei, III, IV, and VI. In addition to characteristic MCB's, the nerve cells contained residual bodies with a granulo-floccular matrix, presumed to represent glycoproteins. The distribution of the mutant gene was studied among 30 blood relatives of the proband at risk and 6 carriers could be ascertained on the basis of a reduced leukocytic β-galactosidase activity. The partly purified enzyme from the patient's liver revealed 20% activity as compared to that of normal controls. All three fractions obtained by DEAE cellulose column chromatography exhibited markedly reduced activity at pH 3.6, but nearly normal activity at pH 6.6. The reduced activity corresponded to the B component of the enzyme as shown by electrophoretic separation. It is pointed out that this case cannot be diagnosed as “generalized gangliosidosis” for the process of ganglioside accumulation was restricted to nervous tissue.
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  • 21
    Electronic Resource
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    Acta neuropathologica 30 (1974), S. 189-196 
    ISSN: 1432-0533
    Keywords: Lafore Bodies ; Polysaccharidosis ; Electron Microscopy ; Epilepsia ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cerebral biopsies of three patients aged 22, 18 and 16 years with myoclonic epilepsy contained Lafory bodies. Two were a brother and sister of consanguineous parents. The Lafora bodies occurred in most neurons but not in glial cells. The ultrastructure of these bodies showed a fibrillar and granular material in the perikaryon and neuropile. In some neurons small Lafora bodies were delimited by a double membrane, suggesting that in early phases they have a membrene which disappears when they become more developed. Other non-specific neuron alterations are described. One of the cases presented in the liver PAS positive bodies of a structure different from the Lafora bodies.
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  • 22
    Electronic Resource
    Electronic Resource
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    Acta neuropathologica 27 (1974), S. 1-10 
    ISSN: 1432-0533
    Keywords: Leprosy ; Lepromatous ; Axonal Bacillation ; Schwann Cells ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary M. leprae bacilli in nerves of 3 patients with lepromatous leprosy were found in the axoplasm of myelinated and unmyelinated nerve fibers. Axonal bacillation occurred in as much as 2% of myelinated axons. Bacilli within Schwann cells were a more common finding in lepromatous leprosy that intra-axonal bacilli. Intra-axonal bacillation probably represents a late stage phenomenon in lepromatous leprosy. Intra-axonal bacilli may contribute to the dissemination of leprosy by migration of bacilli within the axon, and may contribute directly to nerve fiber destruction.
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  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 27 (1974), S. 69-82 
    ISSN: 1432-0533
    Keywords: Chronic Nerve Compression ; Median Nerve ; Guinea-Pig ; Electron Microscopy ; Degeneration ; Regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In guinea-pigs with chronic median nerve compression at the wrist the electron microscopic changes at level of the lesion and both proximal and distal to it have been studied. At the level of the lesion in animals with prolonged motor latency there was a loss of large myelinated fibres. Remaining large fibres had disproportionately thin myelin sheaths or were demyelinated. Regenerating clusters containing myelinated fibres were present. Evidence of degeneration and regeneration of unmyelinated fibres was present in the more severely affected nerves of this group. Distal to the wrist myelinated fibre density recovered, with regenerating clusters and many axons having disproportionately thin myelin sheaths. Midforearm and upper arm levels were normal. In nerves in which no muscle response to electrical stimulation could be recorded in the palm, a few fibres devoid of myelin remained at the wrist. Immediately proximal to it myelinated fibres were rare, the main feature being Schwann cells containing axons devoid of myelin some of which were degenerating. Degeneration of myelinating fibres within regenerating clusters was seen. At the mid-forearm level large myelinated fibres were reduced and increased numbers of regenerating clusters were seen. Evidence of regeneration of unmyelinated fibres was found. The upper arm was normal.
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  • 24
    ISSN: 1432-0533
    Keywords: Myxopapillary Ependymoma ; Tissue and Organ Culture ; Electron Microscopy ; Basement Membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Explants of a myxopapillary ependymoma were grown on collagen-coated coverslips and in organ culture systems using gelfoam sponge matrices and Millipore filter platforms. The tumor cultured on collagen-coated coverslips initially exhibited the cytologic features of simple uni- and bipolar glial cells and later developed an epithelial-like pattern. Delicate branching of argyrophilic cell processes was demonstrated in Bodian preparations. In organ cultures, the tumor architecture was well preserved for approximately 4 weeks, and mitotic figures were present. Invasion of the sponge foam matrix was seen. Later cultures demonstrated progressive perivascular sclerosis and hyalinization. By electron microscopy, the tumor cells in organ culture systems retained the major fine structural characteristics of the original neoplasm up to 27 daysin vitro. The most striking feature in the late stages was the extensive increase and reduplication of basement membrane material, which appeared related to the increase of collagen fibrils in the extracellular space.
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  • 25
    Electronic Resource
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    Acta neuropathologica 27 (1974), S. 247-256 
    ISSN: 1432-0533
    Keywords: Werdnig-Hoffmann's Disease ; Electron Microscopy ; Muscle Biopsy ; Myotube-like Cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An ultrastructural study was carried out on muscle biopsies of 7 children with Werdnig-Hoffmann's disease. The muscle fibres were classified into 3 categories: 1. Muscle cells of normal diameter without any distinct or only slight changes. 2. Small muscle cells with a large central nucleus with the appearance of myoblast at a later stage of development. 3. Cells resembling myotubes containing in a common basement membrane two to four cells at different stages of maturation. Myoblast and myotube-like cells seemed to resemble foetal muscle fibres. Such fibres appear to represent an arrest in maturation rather than muscle atrophy.
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  • 26
    ISSN: 1432-0533
    Keywords: Jimpy Mouse ; Electron Microscopy ; Mouse Mutant ; Myelination ; Axonal Growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A quantitative study of the myelination and axonal growth in the corpus callosum and posterior columns of the spinal cord in the Jimpy mouse gave the following results: The reduction in the number of myelinated fibers is much more important in regions with late myelination, e.g. corpus callosum and pyramidal tracts than in the previously myelinated fascicles of Goll and Burdach. There is an important delay in the increase in volume of axons particularly within the structures of late myelination. The importance of the lacking axonal growth in relation to myelination is discussed.
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  • 27
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    Acta neuropathologica 30 (1974), S. 73-84 
    ISSN: 1432-0533
    Keywords: GM1 Gangliosidosis ; Friesian Calves ; Inborn Metabolic Error ; Histochemistry ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Histoenzymic and ultrastructural alterations in the brains of seven calves with GM1 gangliosidosis are described. A decreased oxidative enzyme activity in neurons was accompanied by an increase in acid phosphatase activity. Membranous cytoplasmic bodies were present in neurons and glia. The periodicity of the membranes was about 5.5 to 6.0 nm. Electron-dense, membrane-bound inclusions were present in perithelial cells. The lesions were compared with those of gangliosidoses in other species.
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  • 28
    ISSN: 1432-0533
    Keywords: Aseptic Meningitis ; Atheromatous Material ; Hypersensitivity ; Electron Microscopy ; Macrophages ; Pia-Arachnoid ; Granuloma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 500 mg of sterile pooled human atheromatous material was injected into the cisterna magna of 6 mongrel dogs. Repeated cisternal punctures were done at various intervals until sacrifice from 1 day to 28 days following injection. CSF was obtained for cell count, sugar, protein and analysis in the Technicon 6/60 which measured 14 additional chemical and enzymatic variables. All 6 animals showed a prompt cerebrospinal fluid (CSF) pleocytosis which largely subsided during the first 2 weeks after injection. Increased CSF protein content developed more slowly, but was more prolonged than the pleocytosis. There was a variable decrease in CSF sugar and increase in CSF lactate dehydrogenase, calcium and inorganic phosphorous. Light and electron microscopic studies showed an intense acute inflammatory reaction with marked phagocytosis of the foregin material, probably by arachnoidal cells and moderate edematous changes in the astrocytic processes at the site of injection. During the first 2 weeks after the injection the inflammatory reaction became chronic and the edematous changes in the medulla subsided.
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  • 29
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    Acta neuropathologica 30 (1974), S. 175-181 
    ISSN: 1432-0533
    Keywords: Reacting Astrocytes ; Phagocytosis ; Experimental Gliomas ; Ethylnitrosourea ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structure of reacting astrocytes in experimental gliomas has been described. These tumours were induced transplacentally by 30 mg of N-ethyl-N-nitrosourea per kg of body weight injected into the tail vein of pregnant BD-IX rats on the 15th day of gestation. In tumour-bearing animals astrocytes undergo striking morphological changes and show increased mitotic activity. Reacting astrocytes around gliomas display large, eccentric, irregular nuclei and the abundant cytoplasm contains an increased number of cell organelles. The most dramatic increase is in glial filaments: these form thick bundles at the periphery of the cells and in the processes which are frequently seen around demyelinated axons. Reacting astrocytes engulf and break down myelin sheaths: their remnants, lamellar inclusion bodies and lipid droplets, are present in the cytoplasm. Extravasated erythrocytes are also surrounded by and digested in reacting astrocytes. Numerous lysosomes could provide the necessary enzymes for the phagocytic activity of these cells.
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  • 30
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    Archives of microbiology 98 (1974), S. 271-274 
    ISSN: 1432-072X
    Keywords: Proteus vulgaris ; Bacteriocin ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The intracellular development of a bacteriocin in a strain of Proteus vulgaris was investigated. Particles which resemble the bacteriocin make their appearance in the cell after 60 min induction with mitomycin C. At this stage they appear as broad bands of tightly-packed phage tail-like structures. With longer periods of induction the bands are disrupted to liberate individual phage tail-like particles.
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  • 31
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    Archives of microbiology 98 (1974), S. 311-329 
    ISSN: 1432-072X
    Keywords: Dictyostelium discoideum ; Inorganic Polyphosphate ; Electron Microscopy ; Enzymes ; Polyphosphate Metabolism ; Cellular Slime Mold ; Polyphosphatase ; Polyphosphate-ADP-Phosphotransferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The concentration of inorganic polyphosphates in Dictyostelium discoideum was low in the amoebae. A ca 5-fold increase took place during the early stages of multicellular development and was followed by a decrease during the intermediate stages. Electron micrographs showed the presence of electron dense material in all parts of the differentiating cells. The substance was most frequently observed in various types of vacuoles. Two enzymes of polyphosphate metabolism were identified and studied in cell-free extracts: a polyphosphatase and a polyphosphate-ADP-phosphotransferase. No polyphosphate-glucose-phosphotransferase or polyphosphate-AMP-phosphotransferase activities were observed in the extracts. The specific activity of the polyphosphatase, pH optimum 7.6, was ca 30 nmol Pi·min-1·mg protein-1 at all stages of development. The enzyme activity was not inhibited by 0.01 M orthophosphate. The polyphosphate-ADP-phosphotransferase, pH optimum ca 7.7, was studied in the direction of ATP. The enzyme specific activities were very low, about 0.2 nmol P·min-1·mg protein-1, and rather constant during differentiation. The enzyme activity was inhibited by orthophosphate and by excess ADP. It was concluded that the polyphosphate-ADP-phosphotransferase did not contribute significantly to the formation of ATP during multicellular development, and that polyphosphate did not act as a phosphagen in the differentiating cellular slime mold. It was suggested that polyphosphate served as a phosphate store and as a means of regulating the intracellular orthophosphate concentration during development.
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  • 32
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    Archives of microbiology 97 (1974), S. 27-38 
    ISSN: 1432-072X
    Keywords: Mass Mating ; Electron Microscopy ; Cell Fusion ; Membrane Structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The process of mating reaction of Saccharomyces cerevisiae was studied by electron microscopy. Prior to the dissolution of the part of the cell walls separating the conjugating pair of cells, the thinning of the electron transparent layer of the cell wall occurs at the part toward which the nuclei are migrating. After the dissolution of the cell walls of the conjugating cells, the cell membranes become associated with each other, then to be broken and rejoined. The first diploid bud emerges from about the middle of the zygote. The morphological changes during the mating reaction are discussed in relation to the biochemical changes so far known.
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  • 33
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    Archives of microbiology 99 (1974), S. 281-294 
    ISSN: 1432-072X
    Keywords: Spirochete ; Artemia ; Brine Shrimp ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. A spirochete which occurs in tissues of the brine shrimp,Artemia salina, was studied by light microscopy and transmission electron microscopy. A total of seven infected shrimps were encountered. 2. Under darkfield illumination, most spirochete cells inArtemia blood were 6–13 μ long and 0.3–0.4 μ wide. Coiling was variable and often irregular. 3. When tissues of the maxillary gland (kidney) and nearby organs were examined by electron microscopy, spirochete cells were found in both extracellular and intracellular locations. These microbes possessed the ultrastructural features typical of members of the Order Spirochaetales: a) a slender protoplasmic cylinder (0.18 μ average diameter), b) axial fibrils (150 A average diameter), and c) an outer envelope or sheath (approximately 75 A thick). 4. Counts made of the number of axial fibrils evident in transverse sections of spirochete cells were consistent with the hypothesis that this spirochete has a 1-2-1 arrangement of axial fibrils. 5. Non-spiral forms were observed in the haemocoel and in the lumen of the maxillary gland.
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  • 34
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    Lung 150 (1974), S. 185-189 
    ISSN: 1432-1750
    Keywords: Paraquat Poisoning ; Morphology ; Electron Microscopy ; Light Microscopy ; Letal Course ; Human Lung ; Lung Fibrosis ; Proliferative Alterations ; Degenerative Alterations ; Pathogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Morphological alterations in the lungs of 3 cases of paraquat intoxication with prolonged lethal course (10, 11, and 25 days) are reported. Combined light-and electronmicroscopic studies reveal that 10 and 11 days after the ingestion of paraquat the endothelium of the occassionally congested capillaries is intact. The basal membranes have only scarce alterations. They are sometimes naked because of shadding of both types of pneumocytes with severe alterations, e.g. lipid accumulation in the cytoplasm. In the vast alveolar edema, red blood cells, some round cells, strands of fibrin, and lamellar cell debris are seen. There are also varying amounts of polymorphnuclear leucocytes and alveolar macrophages with many phagolysosomes and cytosegresomes. Fibroblasts with lipid droplets between the extensive RER form varying amounts of collagen fibrils in the alveolar and sometimes in the very edematous interstitial space. Sometimes surrounded by collagenous material, they thus devoured by macrophages. 25 days after paraquat intoxication a severe alveolar fibrosis, focal interstitial fibrosis, and areas with atelectasis are found. Due to artificial respiration and changed ventilation mechanics, there were large areas with hemorrhage and a honeycomb-like structure of the remaining lung parenchyma. The pathogenesis of the degenerative and proliferative lung alterations is briefly discussed.
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  • 35
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    Archives of microbiology 100 (1974), S. 145-162 
    ISSN: 1432-072X
    Keywords: Complex Flagella ; Fine Structure ; Electron Microscopy ; Optical Diffraction ; Flagellin ; Flagellar Motion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Zellen von Rhizobium lupini H 13-3 besitzen 5–10 peritrich inserierte komplexe Geißeln, deren Feinstruktur durch Hochauflösungs-Elektronenmikroskopie und lichtoptische Diffraktion analysiert wurde. Das Geißelfilament hat einen Durchmesser von 160 Å und besteht aus einem zylindrischen Kern (Durchmesser ca. 110 Å), der fest von drei Bändern einer helikalen Scheide umgeben ist. Die Scheidenbänder sind 49 Å breit, durch 49 Å-Intervalle voneinander getrennt und haben eine Steigung von 31°. Die komplexen Geißelfilamente bestehen aus einem 43 000-Dalton-Protein, das den Kern und die helikale Scheide aufbaut. Beide gehen übergangslos aus dem proximalen Geißelhaken hervor, der einen Durchmesser von 150 Å und eine Länge von 600 bis 800 Å hat. Die Diffraktionsanalyse des Geißelhakens zeigte eine helikale Grundanordnung von globulären Untereinheiten, die ein Oberflächengitter von 5 parallelen Schrauben (Steigung 29° bzw. 33°) bilden, von denen jede fast 11 Untereinheiten pro Helixungang trägt. Die komplexen Geißeln von R. lupini H 13-3 und Pseudomonas rhodos [Schmitt et al.: J. Bact. 117, 844–857 (1974)] sind ein neuer Typ von Bakteriengeißeln. Sie zeigen deutliche Übereinstimmung in der Feinstruktur, der festen Verbindung von helikaler Scheide und Geißelhaken sowie in der Fragilität ihrer Filamente; sie unterscheiden sich deutlich im Molekulargewicht der Flagellinmonomeren (43 000 bzw. 55 000). Zellen von R. lupini H 13-3 führen schnelle, vibrierende Translationsbewegungen aus. Mögliche Mechanismen der Bewegung komplexer Geißeln werden diskutiert.
    Notes: Abstract Cells of Rhizobium lupini H 13-3 possess 5 to 10 peritrichously inserted complex flagella, which were analyzed by high resolution electron microscopy and by optical diffraction. The flagellar filament has a diameter of 160 Å; it consists of a cylindrical core (diameter approximately 110 Å) surrounded by three close-fitting bands of a helical sheath. The helical bands are 49 Å wide, separated by axial intervals, 49 Å wide, and run at an angle of 31°. Complex filaments consist of a 43 000-dalton protein representing the core and the helical sheath. These originate from the proximal hook, which has a diameter of 150 Å and a length of 600 to 800 Å. The diffraction analysis of the hook showed a helical arrangement of globular subunits forming a surface of 5 parallel “small-scale” helices (pitch-angles 29° and 33°, respectively), each carrying almost 11 subunits per period. The complex flagella of R. lupini H 13-3 and Pseudomonas rhodos [Schmitt, et al.: J. Bact. 117, 844–857 (1974)] represent a novel type of bacterial flagella. There is agreement in their fine structures, in the intimate connection of the helical sheath and the core, and in the fragility of their filaments. Thery are clearly distinguished by the molecular weights of their flagellin monomers (43 000 and 55 000, respectively). Cells of R. lupini H 13-3 show fast, vibrating, translational motions. Possible mechanisms of complex flagellar motion are discussed.
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    Archives of microbiology 100 (1974), S. 307-328 
    ISSN: 1432-072X
    Keywords: Citrate Lyase ; Subunit Structure ; Electron Microscopy ; Reaction Inactivation ; Rhodopseudomonas gelatinosa ; Phototrophic Bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. Citrate lyase (EC 4.1.3.6) from Rhodopseudomonas gelatinosa has been purified to homogeneity by protamine sulfate fractionation, chromatography on DEAE-Cellulose and gel filtration. The final enzyme preparation had a specific activity of 138 units per mg of protein and was purified 43-fold over the crude extract. Analysis of citrate lyase by sedimentation equilibrium experiments and gel filtration gave molecular weights of 530000 and 560000, respectively. 2. Electron microscopic investigations of negatively stained enzyme molecules and image analysis showed that citrate lyase is composed of six large and six small subunits; they are arranged in two hexagonal rings lying face to face, each containing, in alternating sequence, three large and three small subunits. The enzyme molecule is 160 Å in diameter and about 100 Å thick. 3. Treatment with sodium dodecylsulfate and mercaptoethanol dissociated citrate lyase into three proteins. Protein III (small subunit) had a molecular weight of 30000 and contained the pantothenate; protein II (large subunit) had a molecular weight of 61000; protein I (M r =97000) was probably an aggregate of II and III. 4. Based on the results obtained a model of citrate lyase was constructed. 5. Purified citrate lyase was obtained from R. gelatinosa in a deacetylated and largely oxidized form. The enzyme was activated by reduction with dithiothreitol (3 mM) and subsequent acetylation with acetic anhydride (1.75 mM). 6. The enzyme was subject to reaction inactivation, the extent of which depended on the concentration of Mg2+.
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  • 37
    ISSN: 1432-072X
    Keywords: Bdellovibrio bacteriovorus ; Spirillum serpens ; Freeze Fracture ; Electron Microscopy ; Ultrastructure ; Membrane Damage ; Organismic Associations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The freeze-fracture technique and electron microscopy have been used to demonstrate that localized damage is inflicted upon the cytoplasmic membrane of Spirillum serpens VHL within 20 to 30 min after the start of its association with Bdellovibrio bacteriovorus 109D. This damage is not observed in uninfected Spirillum cells, nor in infected cells within the first 10 min. This damage takes the form of a “blister” which, when viewed stereoscopically in electron micrographs, is seen to project toward the interior of the Spirillum cell. Shortly after its formation, the blister becomes elaborated into a series of ridges which may assume forms ranging from an elaborate spiral to a series of loops or knots. The formation of a blister is shown to involve both the inner and outer leaves of the membrane bilayer, and evidence is presented to indicate that the blister site corresponds to the site of attachment of the Bdellovibrio cell. The hypothesis is proposed that this ultrastructural damage is the cytological basis for the controlled and localized leakage through the cytoplasmic membrane into the periplasmic space of the Spirillum cell at locations adjacent to the Bdellovibrio cell. It is suggested that this localized membrane damage may be the ultrastructural basis for the high efficiency with which bdellowvibrios are known to incorporate cytoplasmic materials from the other bacteria in whose periplasmic spaces they develop.
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  • 38
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    Cell & tissue research 150 (1974), S. 167-178 
    ISSN: 1432-0878
    Keywords: Pigment cell ; Red hair ; Sunburn ; Man ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pigment cells of human red hair (pheomelanocytes) are never connected to keratinocytes by desmosomes or other defined cell junctions. In the dendritic processes of pheomelanocytes, thin filaments, about 50–80 Å in diameter, and microtubuli can be observed. Early prepheomelanosomes contain loosely arranged filaments. With the onset of pheomelanogenesis dense material is deposited on the filaments. Distinction between late prepheomelanosomes and pheomelanosomes is not clearly possible, because of the disorganized appearance of the content. Furthermore, the content of pheomelanosomes sometimes seems to be disintegrated. By means of the DOPA reaction, tyrosinase activity is shown to be present in: a) prepheomelanosomes, b) large cisternae apposed at one side of dictyosomes, c) small cisternae of the smooth endoplasmic reticulum, and d) coated and uncoated vesicles. The results suggest that red pigment granules are formed in a manner similar to that of melanin granules. It is further assumed that an inadequate stability of pheomelanoprotein accounts for the inability of red-haired people to develop effective protection against ultraviolet light.
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  • 39
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    International Journal of Quantum Chemistry 8 (1974), S. 315-316 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 40
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    International Journal of Quantum Chemistry 8 (1974), S. 347-362 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The algebra of irreducible tensor operators is developed in the intermediate-field coupling case. The Wigner-Eckart theorem is formulated for a simple irreducible tensor operator as well as for the Kronecker and scalar products of these operators. The expressions required for the calculation of Coulomb repulsion, crystal field splitting, spin-orbit interaction, and Zeeman effect are given in detail. Recent applications to various problems in spectroscopy and magnetism of transition metal compounds are referred to.
    Additional Material: 1 Ill.
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  • 41
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    International Journal of Quantum Chemistry 8 (1974), S. 539-546 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: SCF equations for any pure spin state are given for a spin-free system with many-particle interactions. The equations are very simple and explicit. Due to the use of different antisymmetric requirement our equations are different from some of the other methods. In our method, the abstract group theory formalism is converted into some explicit and straightforward equations which makes the many-particle interaction problem easier to handle.
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  • 42
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    International Journal of Quantum Chemistry 8 (1974), S. 635-642 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: General formulas are obtained for evaluating a basic type of one-center two-electron integral which arises in the computation of expectation values of spin-spin and spin-orbit operators over explicitly correlated wave functions. The correlation terms are assumed to be in the form of products of Slater functions and powers (not necessarily integer) of the interelectronic coordinate rij.
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  • 43
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    International Journal of Quantum Chemistry 8 (1974), S. 17-28 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ground state energy of the He2 system is calculated according to the techniques described in Paper I around the van der Waals equilibrium, without assuming the constancy of the intraatomic correlation energies. The second-order results do not present an attractive region; the S2 decrease of the intraatomic correlation correlation corrections is larger than the attractive interatomic correlation corrections. The further orders reverse progressively the situation and finally give a qualitatively correct potential curve after the fifth order. Reaching almost exact solutions in the considered basis, one can demonstrate that the intermolecular calculation of the system A + B in the union of the basis for A and B involves an energy decrease which simply represents the effect of the extension of the basis set; and that a proper intermolecular calculation must compare the A + B energy with the A and B energies calculated in conveniently extended basis sets including the vacant MO's of the partner.
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  • 44
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    International Journal of Quantum Chemistry 8 (1974), S. 79-82 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecular orbitals of some of the 3d-transition metal phthalocyanines have been calculated. π-Electron charge densities over the atomic sites and the optical properties of the metal phthalocyanines have been calculated. The effect of the introduction of different metal atoms in the centre of the organic ring on the physical properties of the metal phthalocyanines has been discussed.
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  • 45
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    International Journal of Quantum Chemistry 8 (1974), S. 107-117 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some problems connected with the convergence of iterative solutions of the Hartree-Fock equations for the open shell systems are discussed. The nonuniqueness of the Hartree-Fock operator form is used.The method of iterating by the operator's power is developed for obtaining solutions of the Hartree-Fock equations. Some particular results for the molecules Li2+, Li2- are presented.
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  • 46
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    International Journal of Quantum Chemistry 8 (1974) 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 47
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    International Journal of Quantum Chemistry 8 (1974), S. 951-970 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Simple rules for an estimate of the correlation effects in the low-lying states of alternant hydrocarbons, as described by the Pariser-Parr-Pople Hamiltonian, are formulated. These rules are based on the alternancy and spin symmetry classification of states in both strongly and weakly correlated limits and on the valence bond characteristics of those states in the fully correlated limit. It is shown that the largest effect of the electron correlation will be found for the singlet “minus” states (using Pariser's classification of the alternancy symmetry species), a smaller effect for the triplet “plus” states, and a much smaller effect for the remaining states. These rules are exemplified by limited CI calculations including all monoexcited and all mono- and bi-excited configurations, respectively, for a number of π-electronic systems. In view of these rules the success of the PPP model in the monoexcited CI approximation may be understood.
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  • 48
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    International Journal of Quantum Chemistry 8 (1974), S. 263-266 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The two-center core-electron attraction integral VAB in zero-differential overlap semiempirical MO methods is examined. It is concluded that core-valence orthogonality and valence symmetrical orthogonalization effects must be considered, and that these effects provide justification for the CNDO/2 approximation VAB = ZBγAB.
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  • 49
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    International Journal of Quantum Chemistry 8 (1974), S. 293-314 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The problem of the evaluation of first- and second-order energies by the use of arbitrary variational wave functions is examined in detail for time-independent perturbations as well as for time-dependent perturbations. By using a compact formalism the general formulae to be used for the case of a fully optimized set of variational parameters are readily obtained and the most prominent features are examined. The generality of the approach is tested by showing how some widely used methods are obtained by using particular types of variational wave functions. The case of incompletely optimized sets of variational parameters is examined examined extensively and several approaches at different levels of approximation are proposed. Emphasis is put upon the importance of considering, in the calculation of higher-order energies, the variational parameters which may be of negligible importance, and thus often neglected, in the absence of perturbations.
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  • 50
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    International Journal of Quantum Chemistry 8 (1974), S. 363-372 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The spin projected extended Hartree-Fock equations for successive optimization of the orbitals are derived for the four-electron case and applied to butadiene in the PPP approximation. The method shows an excellent convergence and gives 91.4% of the correlation energy for the given model-Hamiltonian.
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  • 51
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    International Journal of Quantum Chemistry 8 (1974), S. 427-433 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple equation for the evaluation of resonance integrals from overlap integrals and ionization potentials of the molecular fragments is suggested for molecules-in-molecules π electron calculations. The singlet π → π* transition energies of some benzene derivatives containing donor substituents were calculated. The best results were obtained if in the expression of the resonance integral the first experimental ionization potential of the methyl derivative of the donor groups is used.
    Additional Material: 4 Tab.
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  • 52
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A modified INDO procedure has been used to calculate the proton hyperfine splittings in benzyl and the isoelectronic anilino, phenoxy and 2-azabenzyl as well as 2- and 3-thenyl radicals. The present procedure differentiates between s-, p- and d-orbitals on an atom in estimating various integrals involving them, satisfies the rotational invariance requirements and employs an orthogonalized basis set of atomic orbitals for obtaining core-Hamiltonian matrix elements. The calculations based on using the exponents which depend only on the type of orbital and the nature of atom fail to provide correct relative order of ortho and para proton splittings in benzyl as well as anilino, phenoxy and 2-azabenzyl radicals. On the other hand, use of the exponents which are modified according to the charge densities in various orbitals leads to a high absolute value for para proton splitting compared to that for ortho proton splitting which in case of all these radicals is in agreement with experiment. A spin density calculation on benzyl, anilino and phenoxy radicals considering the variation of one-center one-electron and one-center two-electron integrals for different protons with their charges is found to yield further improvement in the relative order of ortho and para proton splittings in all these radicals. In 2- and 3-thenyl radicals the role of 3d-orbitals on sulfur has also been examined. To our knowledge, no unrestricted INDO calculations including 3d-orbitals on sulfur have been reported in the literature so far.
    Additional Material: 1 Ill.
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  • 53
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that any expectation value of any observable associated with a molecule is the sum of loge contributions and of loge pair contributions. This result provides a rigorous theoretical basis for the study of additive properties of molecules.It is demonstrated that molecular wave functions (exact or approximate) can be expressed as a sum of functions corresponding to the various electronic events. Furthermore any of these event functions can be expressed in terms of correlated loge functions. This expression suggests many kinds of variational procedures of calculating wave functions (known methods and new ones).The case in which noncorrelated completely localized loge functions are used is discussed. If continuous functions are used the variational equation reduces to a sum of independent variational equations, each one corresponding to a particular electronic event. This is not so when discontinuous functions are used or when a delocalized function is added to replace the correlation interloge function.The noncorrelated completely localized loge model is analyzed in more detail. It is seen that local spin operators can be introduced and that each event density operator is the product of the loge density operators. Therefore that model is an independent loge model. The corresponding generalized self-consistent field equations are derived. This treatment helps us to understand how a localized state of a molecule can produce an ion containing a delocalized region, a phenomenon which is sometimes at the origin of some misunderstanding in photoelectron spectroscopy. Finally it is seen how virtual loge functions can be introduced to describe excited states.
    Additional Material: 2 Ill.
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  • 54
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    International Journal of Quantum Chemistry 8 (1974), S. 605-617 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is proposed for the calculation of matrix elements among various states of atoms. A set of tensor operators is the only entity in the formalism, and all formulas involve merely the vacuum expectation values of these tensor operators and the recoupling transformation coefficients. Some numerical examples are given for the Coulomb interaction matrix elements.
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  • 55
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    International Journal of Quantum Chemistry 8 (1974), S. 643-676 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A brief survey of the maximum overlap method is presented and some computational aspects of the approach are discussed. The hybrid compositions and bond overlaps are reported for some thirty small ring compounds and a list of characteristic hybrids for various structural environments is given. The table of characteristic hybrids is extended to acyclic hydrocarbons and the transferability of the maximum overlap hybrids is demonstrated. Those aspects of the method which depend on geometrical properties of molecules have been considered in some details and the discussion is extended to some structural features of cyclic systems. In particular the asymmetry of bonds of spiro carbon atom is examined and rationalization of puckering of large macrocyclic systems is presented. In the summary it is pointed to the method and its potential to discuss structural aspects of molecules at the particular level of accuracy expected to be of great use in organic and physical organic chemistry. Further development and improvement of the method is mentioned, but already in the present form it can produce hybrids which may constitute a useful basis for other more ambitious semiempirical calculations.
    Additional Material: 6 Ill.
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  • 56
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    International Journal of Quantum Chemistry 8 (1974), S. 423-426 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A general formalism in order to deal with SCF eigenspace manipulation is developed. It can be shown that the initial generalized secular equation splits into a set of secular equations, each of which in turn can modify independently any predetermined subset of the SCF manifold.
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  • 57
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    International Journal of Quantum Chemistry 8 (1974), S. 435-450 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The concept of pseudopotentials offers much attractiveness for the quantum mechanical evaluation of the physical properties of atoms and molecules. The ideas of Hellmann, in which the repulsive and fermion character of inner electrons can be mimicked by an experimentally fitted, exponentially damped potential term, are especially attractive. Unfortunately, it is found that such a simple expression can only be used in a very limited number of cases, such as for the alkali metals, and even then fails for the simple case of lithium.The present study shows that the Hellmann idea can readily be extended by including a second “shielded potential” term evaluated from tabulated previous Hartree-Fock calculations. The new expression for the model pseudopotential is both simple and effective. With it, the inner potential of any of the alkali metal atoms, including lithium, can be represented so that calculation of the molecular properties of the metal dimers can be accomplished. Calculations for Li2, Na2, and K2 show the binding energies and equilibrium interatomic distances to be quite well given, in agreement with both chemical experience and spectroscopic evidence.
    Additional Material: 3 Ill.
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  • 58
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    International Journal of Quantum Chemistry 8 (1974), S. 745-754 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chemical shift and the diamagnetic susceptibility of the hydrogenic atom with magnetic dipole and origin of the external magnetic field vector potential noncoincident with the hydrogenic nucleus have been calculated from perturbation theory using a set of expansion functions whose radial parts are single exponent associated Laguerre functions. In contrast to hydrogenic expansion functions these functions give rapid convergence to the exact values of the second-order energy summations when centred at the hydrogenic nucleus. The rate of convergence is fairly insensitive to the choice of expansion function exponent.
    Additional Material: 5 Tab.
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  • 59
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    International Journal of Quantum Chemistry 8 (1974), S. 789-797 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We calculated the Verdet constant of the hydrogen molecule. We found that the angle of rotation may be represented by φ0 = A0Hv2/(v02 - v2)2 where A0 is 3.23 × 10-33 microminutes sec2 per oersted-cm-atmosphere. This is in agreement with the experimental observations where φ0 is given by the same frequency dependence with the constant A0 × 2.72 = 10-33 in terms of the same units.
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  • 60
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    International Journal of Quantum Chemistry 8 (1974), S. 893-899 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The spin-projected extended Hartree-Fock equations discussed in Part I for an even number of electrons are given here for the odd-electron case.
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  • 61
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    International Journal of Quantum Chemistry 8 (1974), S. 925-940 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Model Hamiltonians for all valence electron calculations are examined with regard to the possibility of obtaining consistent sets of matrix elements for the description of electromagnetic processes such as photon absorption, optical activity, and magneto-optical activity. Linear and angular momentum and position operator matrix elements are related to Hamiltonian matrix elements through symmetry relations and equations of motions. The possibility of elimination of empirical interatomic matrix elements is studied.
    Additional Material: 1 Tab.
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  • 62
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    International Journal of Quantum Chemistry 8 (1974), S. 163-169 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The connection between the electron coordinates permutation group and the molecular point group is exhibited in the framework of the Heitler-London method. It is shown that the initial wave function of a molecule in the Heitler-London method can be written in such a form, that the effect of the point group operations upon this function corresponds to the permutation of the sets of electron coordinates of the ions and the subsequent multiplication of this function by some constants.
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  • 63
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    International Journal of Quantum Chemistry 8 (1974), S. 209-221 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: General forms for asymptotic wave functions are derived from properties of the relevant Green's function. The use of separable potentials constructed from the asymptotic functions is described and the relation with integral transform functions is discussed.
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  • 64
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    International Journal of Quantum Chemistry 8 (1974), S. 247-253 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The energies of the single-configuration lowest π - π* singlet and triplet states of some conjugated hydrocarbons have been calculated by the MC-SCF method using the conjugate-gradient technique of minimisation. The results are compared with those calculated by other methods currently in use, like (a) single-configuration calculation with VN-1 potential for virtual orbitals; (b) CI calculation involving singly excited states; and (c) TDHF method. It has been concluded that the results for the MC-SCF method are very good, considering that only a single open-shell configuration is involved.
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  • 65
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    International Journal of Quantum Chemistry 8 (1974) 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 66
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    International Journal of Quantum Chemistry 8 (1974), S. 335-345 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In a previous publication [1] we analyzed the stability of rare gas halides on the basis of exchange perturbation theory of the Rayleigh-Schrödinger type, using a three-center, four-electron model. In this paper, the analysis is extended to a (n + 1)-center, (n + 2)-electron model for rare gas halides of composition RXn, where R is the rare gas atom and X the halogen atom, in order to investigate the validity of the three-center, four-electron model. The compounds analyzed are XeFn, XeCln, KrFn and KrCln with n = 3 and 4, in different geometric configurations and for different states of total spin S. As before, we use exchange perturbation theory in first and second orders. The results are in good agreement with those obtained in the previous analysis and with experiments. Specifically, it is found that chlorides of rare gas atoms are not stable, that XeF4 has the square-planar configuration and that trifluorides cannot exist. The possible existence of KrF4 is discussed.
    Additional Material: 2 Ill.
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  • 67
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    International Journal of Quantum Chemistry 8 (1974), S. 373-394 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A generalized form of the coupling operator technique in SCF theory has been developed. In the formalism presented here, the monoconfigurational problem may be treated as a particular case of the multiconfigurational framework. The matrix form of the operators has been analyzed; in the LCAO context a structure has been found which is very adequate for computational purposes.Some examples are also presented which show the usefulness of the theory, emphasising the CNDO and INDO approximations. Within the application of the method to ab initio calculations, some He and second row atoms states have been studied. The He first excited singlet is also studied, the result of the analysis of such a problem being that the nonorthogonality between the singlet functions of the fundamental and of the first excited states play a primordial role in the efficiency of the method.In no case have the calculation problems, appearing in the application of the theory, been of a more difficult nature than those normally found in the application of the formalism for closed shells.
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  • 68
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    International Journal of Quantum Chemistry 8 (1974), S. 467-489 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A variational calculation of the interaction between two H2 molecules using minimal basis set of 1s functions is performed to check the efficiency of various versions of the perturbation theory for intermolecular interactions. The matrix procedure starting with the zero-order Hamiltonian which is symmetric with respect to intermolecular electron permutations shows better convergence than the procedures using nonsymmetric zero approximations. This conclusion follows from the calculations of ground state and four lowest excited states for three geometric configurations of the H4 system. The behaviour of the potential curves is interpreted in terms of symmetric perturbation theory. The various contributions to the interaction energy are considered in detail. The importance of charge transfer states for the description of the intermediate range of intermolecular separations is specially emphasized.
    Additional Material: 9 Ill.
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  • 69
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    International Journal of Quantum Chemistry 8 (1974), S. 559-564 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transitions from symmetry-adapted to symmetry-broken solutions of variational problems are classified according to the nature of the discontinuity involved. Two systems in which a second-order transition occurs are studied.
    Additional Material: 3 Ill.
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  • 70
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    International Journal of Quantum Chemistry 8 (1974) 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 71
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    International Journal of Quantum Chemistry 8 (1974), S. 693-706 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radial one-electron Schrödinger equation can be written as a nonlinear first-order differential equation by making a suitable logarithmic transformation. The resulting Riccati equation has the equivalent Hammerstein integral representation [1], \documentclass{article}\pagestyle{empty}\begin{document}$$ \beta (r) = \int_{r' = 0}^\infty P(r') N(r,r')dr' \quad 0\buildrel{〈}\over{=} r 〈 \infty $$\end{document} where the kernel, N(r, r′) is \documentclass{article}\pagestyle{empty}\begin{document}$$ N\left( {r,\,r\prime} \right) = H\left( {r,\,r\prime} \right)\exp \left\{ {\int_{\xi = r\prime}^r {R\left( \xi \right)\beta \left( \xi \right)d\xi } } \right\} $$\end{document} and H(r, r′) is the Heaviside unit step function. This kernel is a more general one than that developed in ref. [1]. Both kernels apply in cases where the Riccati equation corresponds to a Sturm-Liouville problem.It is shown that this integral equation can be integrated by parts so that, for any local potential, the integrand decreases as the cyclic folding procedure is applied. During this cyclic folding, the kernel generates an equation that contains only coefficients of β(r)0 and β(r)1. Consequently, after truncating at the end of the nth cycle, it is possible to write down a Padé-type approximation to the logarithmic derivative as a known function of the independent variable. All coefficients in this approximation can be evaluated as simple algebraic formulations of P(r), R(r), and integrals over P(r).
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  • 72
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    International Journal of Quantum Chemistry 8 (1974), S. 171-177 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the framework of the Heitler-London method, a method for determining the allowed molecular multiplets is proposed. The method is based on the connection of the total molecular spin with the permutation symmetry of the coordinate wave function and on the isomorphism of the molecular point group with a certain subgroup of the electron permutation group. The method does not depend on the approximation in which the molecular ions are considered.
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  • 73
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    International Journal of Quantum Chemistry 8 (1974), S. 765-775 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The method of orthonormality-constrained variation is extended using a dual-basis set instead of a single orthonormal basis. The complete and the partial variation methods are discussed and applied to electronic systems. It is found that the present formulation leads to the most general equation in the coupling operator method.
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  • 74
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    International Journal of Quantum Chemistry 8 (1974), S. 799-816 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the spirit of Löwdin's extended HF scheme, an SCF method for the description of the molecular ground state, based on complex molecular orbitals, is developed. As a special case the method of parity mixing in orbitals is formulated. A calculational procedure for solving derived secular equations is described and numerical results, obtained in the minimal basis set, are reported for the N2 and CO molecule. Resulting ground state energies are close to the energies of the CI calculations with the same set of orbitals.
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  • 75
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An antisymmetric pair function can be built upon two kinds of monoelectronic functions, the former ones being correlated local functions and the second ones nonlocal functions taking external effects into account. This function, brought into the generalised product function procedure by means of the density matrix formulation, makes possible the study of correlation within N-electronic systems. The results of a first application of this method to the fundamental and to 1P and 3P excited states of two-electron systems are given.
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  • 76
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    International Journal of Quantum Chemistry 8 (1974), S. 61-72 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A contracted Gaussian basis set capable of describing about 63% of the correlation energy of N2 has been used in a detailed configuration-interaction calculation. Second-order perturbation theory overestimated the correlation energy by 23-50% depending on how H0 was chosen. Pair-pair interaction affects the correlation energy by about 20% while quadruple excitations have an 8% effect.
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  • 77
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    International Journal of Quantum Chemistry 8 (1974), S. 83-89 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that the turn-over rule which is used to simplify matrix elements between spin-projected Slater determinants may also be used to simplify formation of matrix elements between any orthonormal set of spin-coupled Slater determinants. The coefficients for the spin-coupling may then be chosen freely to reduce the number of important configurations in the secular equation.
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  • 78
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    International Journal of Quantum Chemistry 8 (1974), S. 137-150 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to make a better assessment of the distinguishable electron method developed by Kirtman and co-workers, we have applied the method to some two-electron atoms and to H2 and LiH. Our results lend support to the contention held by Kirtman and co-workers that the distinguishable electron method is a practical way of calculating reasonably accurate physical properties.
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  • 79
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    International Journal of Quantum Chemistry 8 (1974), S. 523-537 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper we show that with the equivalent transformation Pr = (-1)P(Pσ)-1 the spin function dependent methods such as Slater's method without group theory or Goddard's method with group theory differ only in different antisymmetric requirements from the present Waller-Hartree spin function free method. There exists a one-to-one correspondence between Slater's determinantal wave function and the Waller-Hartree double determinantal wave function. Explicit expressions for the S2 operator, Löwdin's spin projector, matric basis and several different forms of spin-projected functions are given for the Waller-Hartree formalism. The results are compared with other methods including those of Slater, Matsen, Gallup, Goddard and Segal. The differences are quite significant. New spin operators are worked out using creation-destruction operators. A knowledge of group theory is not required in this Waller-Hartree method. We have also shown that the Waller-Hartree method is more convenient than Slater's method with spin functions especially in the evaluation of the functional HΨ/Ψ. The advantages and disadvantages in the use of a linear combination of N! Hartree products and linear combinations of all possible double determinants are discussed. In addition, a formula for the calculation of the Sanibel coefficients C(S, M, i) is obtained.
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  • 80
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for quantitative comparison of various conformers of cyclic macromolecules in terms of nonbonded interaction energy terms is proposed. The first step in the procedure is an analytical evaluation of a set of Cartesian atomic coordinates consistent with the ring closure condition and prescribed values for internal parameters. A variant of the same technique enables different conformations of the macromolecule to be generated. Nonbonded interactions of the electrostatic, polarization and dispersion type and van der Waals repulsion are calculated using the generated coordinates, empirical bond polarizability data and results of simple molecular orbital calculations. An application of the proposed techniques to the closed symmetric conformation of valinomycin indicates that the macromolecule by itself is somewhat constrained in this state but that its affinity for a potassium ion is very strong - much stronger than the hydration energy of the latter.
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  • 81
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    International Journal of Quantum Chemistry 8 (1974), S. 623-625 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 82
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    International Journal of Quantum Chemistry 8 (1974), S. 857-892 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multiconfiguration wave functions constructed from contracted Gaussian-lobe functions have been found for the ground and valence-excited states of urea. ICSCF molecular orbitals of the excited states were used as the parent configurations for the CI calculations except for the 1A1(π → π*) state. The 1A1(π → π*) state used as its parent configuration an orthogonal linear combination of natural orbitals obtained from the second root of a three-configuration SCF calculation. The lowest excited states are predicted to be the n π → π* and π → π* triplet states. The lowest singlet state is predicted to be the n π → π* state with an energy in good agreement with the one known UV band at 7.2 eV. The π → π* singlet state is predicted to be about 1.9 eV higher, contrary to several previous assignments which assumed the lowest band was a π → π* amide resonance band. The predicted ionization energy of 9.0 eV makes this and higher states autoionizing.
    Additional Material: 25 Ill.
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  • 83
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    International Journal of Quantum Chemistry 8 (1974), S. 941-950 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Standard sets of Gaussian atomic orbitals (STO-3G, STO-4.31G) are used to evaluate spin-orbit coupling constants in linear molecules (CO2+, NNN) and spin-orbit effects on singlet-triplet transition intensities in formaldehyde. All spin-other orbit effects have been included. In all cases spin-other orbit interactions form a large fraction of the matrix elements. Simple formulae to evaluate spin-orbit one- and two-electron integrals over atomic orbitals are presented. Standard molecular integral programs can be used for the computation of spin-orbit integrals.
    Additional Material: 1 Ill.
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  • 84
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    International Journal of Quantum Chemistry 8 (1974), S. 971-980 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Wave functions which are a linear combination of H2+-type elliptical orbitals are optimized to provide either an upper bound or a lower bound to the H2+ ground state. For the latter, Temple's formula is used. Three criteria are considered to determine the relative accuracy of these wave functions: (i) energy (calculated versus exact eigenvalue); (ii) average error; and (iii) local energy. Although the lower-bound optimized wave functions obtained are the most accurate available for H2+ from approximate wave functions, they are still inferior to the corresponding upper-bound wave functions by criteria (i) and (ii). In particular, using criterion (ii), it is shown numerically that the upper-bound functions are “correct to second order,” while the lower-bound functions are almost, but not quite, “correct to second order.” Despite this, the local energy analysis, criterion (iii), reveals that the lower-bound wave functions can be more accurate than the upper-bound functions in some regions of space, and hence give more accurate values for physical properties sensitive to these regions. Examples considered are the dipole-dipole and Fermi contact interactions.
    Additional Material: 1 Ill.
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  • 85
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    International Journal of Quantum Chemistry 8 (1974), S. 91-95 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The variation of the polarizability of H2+ and H2 with internuclear separation R = 1.6 - R = 2.4 a.u. for H2+ and R = 1.0 - R = 2.0 a.u. for H2 is determined using a variational method suggested by Das and Bersohn. From these data, values of 〈α〉0,J for which nuclear motion due to zero point vibration and centrifugal stretching is taken into account, are calculated at 300°K. The relative percent increases of the motion averaged values compared to the equilibrium values are as follows: 10.50% for H2+ and 6.52% for H2.
    Additional Material: 4 Tab.
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  • 86
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    International Journal of Quantum Chemistry 8 (1974), S. 119-136 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Various floating one-center perturbation schemes are developed for H2+-like molecules. Previous work for the ‘1s’ hydrogen atom approach is extended through third order in the energy. In the molecular puff approach an exact ‘closed form’ solution is obtained for the zeroth-order problem, which corresponds to a double layer molecular puff. Semianalytical results for the first-order correction to the floating molecular puff wave function and for the energy through third order are developed which offer a convenient alternative to previous approaches. Explicit calculations for ground state H2+ show that for R 〉 3aO the ‘1s’ and the more complicated ‘puff’ treatments are equivalent and that neither the ‘1s’nor the molecular puff function is an adequate zeroth-order wave function for the important intermediate values of R. The usefulness of some of these methods in a variety of problems, where one-center zeroth-order wave functions do appear to be adequate, is discussed briefly.
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  • 87
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    International Journal of Quantum Chemistry 8 (1974), S. 73-78 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The analytical expansion self-consistent field method was employed to perform ab initio calculations for the ground states of the rare-earth ions, Tm2+, 4f13, 2F, and Tm3+, 4f12, 3H, (Z = 69). In each case the total number of basis functions used in the analytical expansions was 29, distributed as follows: 10, 8, 5, and 6, for the symmetries s, p, d, and f, respectively. All of the orbital exponents of the basis functions were optimized repeatedly, to the extent of the single-precision computer representation. Values of 〈rn〉 for the 4f orbital of both ions are also presented, for the convenience of experimentalists.
    Additional Material: 4 Tab.
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  • 88
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    International Journal of Quantum Chemistry 8 (1974), S. 97-105 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Static dipole polarizabilities and shielding factors for the 2p open shell atomic systems are presented using coupled Hartree Fock theory in the framework of the Roothaan formalism. Calculations have been performed for the ground as well as for some valence excited states. A variational approach has been adopted for the determination of the first-order perturbed functions. The results are compared with those obtained from the correlated calculations and other techniques. The shielding factor values are in excellent agreement with the theoretical N/Z ratio.
    Additional Material: 1 Tab.
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  • 89
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    International Journal of Quantum Chemistry 8 (1974), S. 839-855 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The general methods of deriving the extended Hartree-Fock equations are described. The rules for going over from the energy expression in the ordinary method of calculation to that in an extended one are reformulated and illustrated. The extended Hartree - Fock equations for berylliumlike atomic systems based on the use of nonorthogonal radial orbitals are given and solved. The numerical values of overlap integrals and total energies are given and discussed.
    Additional Material: 2 Tab.
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  • 90
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    International Journal of Quantum Chemistry 8 (1974), S. 901-913 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The random phase approximation (RPA) or time-dependent Hartree-Fock approximation (TDHF) is reconsidered for the calculation of the dynamic polarizability for atoms. An integral equation which admits a simple numerical treatment is established. The asymptotic approximation for the electron propagator is tested for its applicability by means of comparisons with earlier results.
    Additional Material: 2 Ill.
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  • 91
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    International Journal of Quantum Chemistry 8 (1974), S. 995-995 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 92
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    International Journal of Quantum Chemistry 8 (1974), S. 179-191 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is given for obtaining the common molecular integrals over generalized gaussian functions: \documentclass{article}\pagestyle{empty}\begin{document}$$ \chi_i = x^{\lambda_i}_i \exp \big\{ - \big(\alpha_i x^2_i + \alpha^{\prime}_i x^{\prime 2}_i + \alpha^{\prime\prime}_i x^{\prime\prime 2}_i\big)\big\} $$\end{document}The present algorithms are expected to be more efficient than those given in earlier work by the same author.
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  • 93
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    International Journal of Quantum Chemistry 8 (1974), S. 201-208 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper, we point out how the precision of the LCAO density matrix elements of polymers may affect the computed properties. We propose to use a more adapted approach in order to evaluate these quantities.
    Additional Material: 2 Ill.
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  • 94
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    International Journal of Quantum Chemistry 8 (1974), S. 255-261 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pair distribution functions evaluated for the 23S state of the helium isoelectronic sequence from the Hart and Herzberg correlated wave functions and those corresponding to the Hartree-Fock approximation are used to determine the shape of the corresponding Coulomb holes. As a consequence of a discontinuity in the Hartree-Fock solution between He and Li+, the Coulomb hole has a different shape for He than for Li+ and the other isoelectronic ions.
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  • 95
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    International Journal of Quantum Chemistry 8 (1974), S. 585-604 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Occupation number representation of the two-dimensional harmonic oscillator and some operator formulae are used in a simple algebraic derivation of complicated integrals. The calculation of full oscillator- and radial integrals of r̂w and exp (\documentclass{article}\pagestyle{empty}\begin{document}$ (iw\hat{\varphi})$\end{document}), where w is an arbitrary positive or negative integer, are performed by an integral transform, leading to a generalized Gauss matrix element. Thus it is possible, because of the back transformation, to derive from one generalized Gauss matrix element all matrix elements which are permitted by the selection rules. Some integrals of r̂w and exp (\documentclass{article}\pagestyle{empty}\begin{document}$ (iw\hat{\varphi})$\end{document}), Laguerre polynomials, and Bessel functions are completely new. For the already known integrals, the mathematical labour is considerably reduced. The relation between the two-dimensional oscillator and the hydrogen atom and their angular momentum properties are discussed. A survey on the various methods applied to the oscillator problem, from complex integration to noncompact Lie groups, and a comprehensive bibliography on this important spectroscopic field are given.
    Additional Material: 604 Ill.
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  • 96
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    International Journal of Quantum Chemistry 8 (1974), S. 755-764 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The difference in the electron correlation between H- and other two-electron atoms is clarified by the introduction of the r12 term in the wave function. By using the expansion of r12, a certain modification of the usual electron correlation factor 1 + Cr12 is introduced and its effectiveness is examined. Calculations are carried out for the ground state and the three lowest excited states (23S, 23P and 21P). The peculiar electron correlation in the ground state of H- is shown by looking at the Coulomb hole for closed- and open-shelf models in comparison with those for other two-electron atoms.
    Additional Material: 2 Ill.
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  • 97
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    International Journal of Quantum Chemistry 8 (1974), S. 777-782 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A virtual orbital transformation is proposed involving pairing of localized occupied orbitals with virtual orbitals. The virtual orbitals are transformed so that each virtual orbital is as “close” as possible to its occupied counterpart, where closeness is the inverse of the particular definition of localization. The appropriate transformation is derived for the special case of Foster-Boys localization, and an illustrative CNDO/2 calculation on HNO is presented. INDO CI results on the series N2, CO, BF indicate that use of this transformation may reduce the number of energetically significant configurations.
    Additional Material: 1 Ill.
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  • 98
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    International Journal of Quantum Chemistry 8 (1974), S. 817-821 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 99
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    International Journal of Quantum Chemistry 8 (1974) 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 100
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    International Journal of Quantum Chemistry 8 (1974), S. 1-15 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Starting from a knowledge of approximate wave functions of the isolated molecules (or atoms) A and B, a method is proposed to build up a zeroth-order ground state and excited configurations for the complex AB in which the molecular orbitals keep their local significance. The standard Rayleigh-Schrödinger perturbation in this basis provides a decomposition of the zeroth-order interaction energy as a sum of the electrostatic and repulsion energy. In the second order, it is possible to identify the classical dispersion and polarization forces (modified by a term of order S2) and two additional contributions which are linked to the exchange possibility. The intramolecular correlation component is taken into account and compared with the correlation on the isolated molecules. It is moreover suggested that since we work in a rather limited basis set, the perturbed energy of AB must be compared with the unperturbed energies of A and B calculated in a basis including the vacant orbitals on their respective partner. Finally a possibility for going beyond the second order is described.
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