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  • 1
    Electronic Resource
    Electronic Resource
    Correlations between size parameters and the amplitude of the excitatory postsynaptic potential evoked by magnetic brain stimulation in human hand muscle motoneurons (1994)
    Springer
    Experimental brain research 98 (1994), S. 128-134 
    Details
    ISSN: 1432-1106
    Keywords: Motoneuron ; Magnetic brain stimulation ; Excitatory postsynaptic potential size ; Macro EMG ; Size principle ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract According to the size principle for motoneurons one would expect that an excitatory stimulus given to a motoneuronal pool should evoke small excitatory postsynaptic potentials (EPSPs) in large and large EPSPs in small motoneurons of the pool. In this study this expectation was tested for the motoneuron pool of the first dorsal interosseus muscle of man excited by a magnetic stimulus given to the contralateral motor cortex. In total, 60 first dorsal interosseus motor units from three healthy volunteers were investigated. For each unit the EPSP size induced by the magnetic brain stimulus was assessed indirectly through a cross correlation of magnetic brain stimuli with motor unit discharges during a slight voluntary contraction. In addition to the indirect measurement of EPSP size, three indicators of motoneuronal size were obtained for each unit: the area the macroelectromyogram (Macro EMG) of the unit encloses with the baseline, the peak-to-peak amplitude of the Macro EMG, and the “true” latency from the magnetic stimulus to the motor unit which in turn provides an indirect estimate for the conduction velocity of the motoneuronal axon. It was found that all three measures of motoneuron size were significantly negatively correlated with the estimates of EPSP amplitude. Such significant negative correlations were found not only in the pooled data but also in the data from each subject individually. These correlations reveal that a magnetic brain stimulus induces small EPSPs in large and large EPSPs in small motoneurons of the first dorsal interosseus muscle of man.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229117
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  • 2
    Electronic Resource
    Electronic Resource
    The relationship between estimates of Ia-EPSP amplitude and conduction velocity in human soleus motoneurons (1993)
    Springer
    Experimental brain research 95 (1993), S. 365-370 
    Details
    ISSN: 1432-1106
    Keywords: Motoneurons ; Size principle ; Ia EPSP ; Conduction velocity ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract There are several parameters associated with motoneuron size, among which are the conduction velocity of the axon as well as the size of the excitatory postsynaptic potential (EPSP) induced by stimulation of Ia afferents in the corresponding muscle nerve. In particular, it has been established in animal experiments that small motoneurons with a low conduction velocity exhibit large Ia EPSPs, whereas large motoneurons with a high conduction velocity show small Ia EPSPs. Thus small motoneurons are recruited earlier than large ones. In this study, we investigated whether such a relationship between motoaxon conduction velocity and size of the Ia EPSPs could also be found for human soleus motoneurons. In total, 36 motor units from six healthy volunteers were activated by a slight voluntary contraction and exposed to 200 stimuli of the tibial nerve in the popliteal fossa. Stimuli were delivered using a special stimulus protocol ensuring a constant pre-stimulus spike density along with a constant rate of discharge of the investigated unit. From the stimulus-correlated spike train data a measure of Ia-EPSP amplitude was obtained, along with the single-unit H-reflex latency. Additionally, for each unit, the so-called surface macro EMG was recorded, which measures the complete electrical activity attributable to the unit investigated. From the macro EMG, the intramuscular delay from arrival of each action potential at the soleus muscle and the detection of the muscle-fiber action potential picked up by the recording needle electrode were measured. All single-unit H-reflex latencies were corrected for the corresponding intramuscular delays. From the corrected latencies, single-unit conduction velocities were obtained. It was found that there was a highly significant negative correlation between the estimate of the single-unit conduction velocity and the inferred size of the Ia EPSP. Thus, it was found that Ia-EPSP amplitudes in human soleus motoneurons follow the size principle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229795
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  • 3
    Electronic Resource
    Electronic Resource
    Quantification of D- and I-wave effects evoked by transcranial magnetic brain stimulation on the tibialis anterior motoneuron pool in man (1994)
    Springer
    Experimental brain research 101 (1994), S. 153-158 
    Details
    ISSN: 1432-1106
    Keywords: Motoneuron ; Transcranial magnetic brain stimulation ; D and I waves ; Tibialis anterior ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Transcranial stimulation in man evokes multiple descending volleys in the spinal cord giving rise to multiple subpeaks in a peri-stimulus-time histogram (PSTH) obtained from a cross-correlation of motor unit discharges with transcranial stimuli. The first volley is termed the D wave, as it is assumed to be evoked by direct excitation of pyramidal tract neurons, whereas the subsequent I waves appear to be generated by indirect excitation of the pyramidal tract neurons via cortical interneurons. It was the aim of this study to obtain an estimate of the effect induced by multiple volleys evoked by transcranial magnetic stimulation on the entire motoneuron pool of the tibialis anterior in awake subjects. A considerable part of a particular motoneuron pool was investigated by sampling responses of a large number (at least 19) from each muscle investigated. In total, three tibialis anterior muscles from three normal volunteers were studied. From each of the 63 units included in this study, a PSTH to 100 transcranial magnetic stimuli and a PSTH to 100 electrical stimuli given to the peroneal nerve were compiled. From the motor unit response to the peripheral nerve stimulation, the latency of the single-unit H reflex peak was obtained. This yielded, the timing of the subpeaks in response to the magnetic stimulation relative to the timing of the H reflex of the same unit, thus eliminating the influence of the peripheral conduction time from the motoneuron to the recording electrode. It was found that 50 (79%) of the motor units exhibited at least two subpeaks in response to the cortical stimulus. All peaks encountered appeared either 1.5 ms–4 ms before or 0 ms–2 ms after the corresponding H reflex. The first peak was assumed to represent the D-wave effect and the second peak an I-wave effect on the motor unit investigated. The relative sizes of the subpeaks exhibited large differences between different units from a single subject. Thus, although the “average unit” showed a larger D- than I-wave effect, in some units the I-wave effect was much more pronounced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243225
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  • 4
    Electronic Resource
    Electronic Resource
    Monosaccharide mit stickstoffhaltigem Ring, XXIII. Darstellung und Reaktionen der freien 5-Amino-5-desoxy-pentopyranosen (1969)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 2822-2834 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch alkalische Spaltung der Hydrogensulfit-Addukte 5-8 wurden die vier isomeren 5-Amino-5-desoxy-pentopyranosen 9-12 dargestellt. Alle vier Piperidin-Zucker liegen in einem Gleichgewicht mit den Piperideinen 13-16 vor, die auf Grund ihrer Cotton-Effekte durch Messung des Circulardichroismus nachweisbar sind. In saurer Lösung werden 9-12 in Amadori-Umlagerungsprodukte 17 oder 19 und 3-Hydroxy-pyridin (18) umgewandelt 5-Amino-3.5-didesoxy-D-erythro-pentopyranose (25) kann nur eine Amadori-Umlagerung eingehen. Die Vorzeichen der Cotton-Effekte der Piperideine 13-16 werden diskutiert. Die ORD-Kurven von 9-11 gleichen denen der entsprechenden normalen Pentopyranosen. Die Hudsonsche Isorotationsregel besitzt für Piperidin-Zucker mit unsubstituierter Aminogruppe im Ring Gültigkeit.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19691020840
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  • 5
    Electronic Resource
    Electronic Resource
    Monosaccharide mit stickstoffhaltigem Ring, XXII. Synthese der vier 5-Benzyloxycarbonylamino-5-desoxy-pentopyranosen. Konformation und anomerer Effekt von Monosacchariden mit stickstoffhaltigem Ring (1969)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 2804-2821 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei allen vier isomeren 5-Benzyloxycarbonylamino-5-desoxy-pentosen ist im tautomeren Gleichgewicht die stickstoffhaltige Sechsringform gegenüber der Furanoseform weit bevorzugt. Die Piperidin-Zucker und ihre Tetraacetate besitzen Sesselkonformation. Es liegt nur die anomere Form oder Konformation vor, in der Substituent an C-1 axial steht. Dies ist bei der D-xylo-Verbindung und D-lyxo-Verbindung die α-Form, bei der L-arabino-Verbindung die β-Form. Von der D-ribo-Verbindung wurden beide Anomere isoliert, von denen die α-Form in der C 1(D)-, die β-Form in der 1 C(D)-Konformation vorliegt. Die Bevorzugung der axialen Stellung an C-1 wird auf sterische Wechselwirkungen zurückgeführt. Monosaccharide mit Acylamino-Gruppe im Ring zeigen eine Abweichung von der Hudsonschen Isorotationsregel. Die ORD-Kurven werden diskutiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19691020839
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  • 6
    Electronic Resource
    Electronic Resource
    Neue, ungewöhnliche photochemische Reaktionen von 3-Aminosydnonen1) (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1737-1745 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Unusually Photochemical Reactions of 3-Aminosydnones1)The light-induced reactions of the 3-amino-4-(phenylthio)sydnones 1a-d surprisingly produce beside diphenyl disulfide the sydnone isomers 11a-d with 2-aza-1,3-diazoniacyclopentadiene-1,4-diolate structure in 2.3-27% yields. The photoreactions of the sydnones 1a, c in the presence of dimethyl acetylenedicarboxylate proceed with formation of the photoisomers 11a or 11c (17%), the benzo[b]thiophene derivative 14 (9-7%), the (phenylthio)fumaric ester 15 (5%) as well as the pyrazole derivatives 13a (18%) or 13c (8%), respectively. The latter are results of a thermal [3 + 2]cycloaddition reaction of the photochemically generated nitrile imine intermediate of type 9 to dimethyl acetylendicarboxylate. Beside 14 (30 - 43%), the same pyrazole derivatives 13a, c are obtained on irradiation of the sydnone isomers 11a or 11c in the presence of dimethyl acetylenedicarboxylate, respectively. The analogous photoreaction of the system 1d/dimethyl acetylenedicarboxylate, produces 11d (0.6%) and 13d (1.8%) in low yields.
    Notes: Bestrahlung der 3-Amino-4-(phenylthio)sydnone 1a-d liefert neben Diphenyldisulfid überraschend die sydnonisomere 11a-d mit 2 Aza-1,3-diazoniacyclopentadien-1,4-diolat-Struktur in 2.3- bis 27proz. Ausbeute. Die Photoreaktionen der Sydnone 1a,c in Gegenwart von Acetylendi-carbonsäure-dimethylester ergeben neben den Photoisomeren 11a, c (17%) noch das Benzo[b]thiophen-Derivat 14 (9-7%), den (Phenylthio)fumarester 15 (5%) sowie die Pyrazol-Derivat 13a (18%) bzw. 13c (8%). Letztere sind Ergebnis einer thermischen [3+2]-Cycloaddition der photochemisch erzeugten Nitrilimin-Zwischenstufe vom Typ 9 an den Acetylendicarbonsäure-dimethylester. Die gleichen Pyrazol-Derivate 13a, c werden neben 14 (30-43%) auch bei der Bestrahlung der Sydnonisomere 11a bzw. 11c in Gegenwart von Acetylendicarbonsäure-dimethylester erhalten. Die analoge Photoreaktion des Systems 1d/Acetylendicarbonsäure-dimethylester führt dagegen in geringen Ausbeuten zu 11d (0.6%) und 13d (1.8%).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140513
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  • 7
    Electronic Resource
    Electronic Resource
    Schnellwachsende nadelförmige KaliumkristalleHerrn Prof. Dr. Ernst Weitz zum 70. Geburtstag gewidmet. (1953)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 86 (1953), S. 1141-1144 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei der Sublimation von Kalium i. Hochvak. werden dünne Kristallnadeln beobachtet, die 150mal schneller wachsen als die normalen Kristalle desselben Metalls.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19530860918
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  • 8
    Electronic Resource
    Electronic Resource
    Thieno[3,4-c]isothiazol. Synthese und Eigenschaften eines neuen nichtklassisch kondensierten Thiophens (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 260-265 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thieno[3,4-cisothiazole]. Synthesis and Properties of a New Nonclassical Condensed ThiopheneThe triphenylthieno[3,4-c]isothiazole 3 is a new 10 π heteroarene containing two different masked 1,3-dipolar systems. Its synthesis from 4-phenyl-1,3.2-oxathiazolylium-5-olate (1) and dibenzoyl-acetylene via the direct precursor 2 as well as its photoelectronic and electronic spectra are desribed. The observed electronic transitions of 3 are compared with the results of a PPP-CI calculation
    Notes: Das Triphenylthieno[3,4-c]isothiazol 3 ist ein neuer 10 π-Heteroaromat, der zwei verschiedene maskierte 1,3-dipolare Systeme beinhaltet. Seine Synthese aus 4-Phenyl-1,3,2-oxathiazolylium-5-olat (1) und Dibenzoylacetylen über die direkte Vorstufe 2 sowie sein Photoelektronen- und Elektronenspektrum werden beschrieben. Die an 3 beobachteten Elektronenübergänge werden mit den Ergebnissen einer PPP-CI-Rechnung verglichen.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120123
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  • 9
    Electronic Resource
    Electronic Resource
    Beiträge zum Mechanismus der photochemischen Reaktionen von Phenylsydnonen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1635-1649 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Mechanism of the Photochemical Reactions of PhenylsydnonesThe light-induced decay of diphenylsydnone (1a in various solvents and in the presence of benzonitrile or 4-chlorobenzonitrile with evolution of carbon dioxide leads to the formation of a nitrile imine intermediate 4 a, whose products are partially isolated and identified. For example, the isomeric triazoles 5 (2.5%) and 7 (7.9%) beside the oxadiazolinone 6a (0.9%) and the phenylhydrazine 8 a (29 %) are formed during the irradiation 1a in acetone. The phenanthridinone derivative 22 and the N-phenylbenzohydrazide 24 are formed during working up of the irradiation mixture from 1a in pure acetyl chloride. Furthermore, the photolyses of 1b, c in acetone and of 1b or 6b in methanol are described. The formation of the isolated products is discussed.
    Notes: Der lichtinduzierte Zerfall des Diphenylsydnons (1a) in verschiedenen Lösungsmitteln sowie in Gegenwart von Benzonitril oder 4-Chlorbenzonitril liefert unter Kohlendioxid-Abspaltung eine Nitrilimin-Zwischenstufe 4 a, deren Folgeprodukte teilweise isoliert und identifiziert werden. Beispielsweise werden bei der Bestrahlung von 1a in Aceton die isomeren Triazole 5 (2.5%) und 7 (7.9%) neben dem Oxadiazolinon 6 a (0.9%) und dem Phenylhydrazin 8 a (29 %) gebildet. Das Phenanthridinon-Derivat 22 und das N-Phenylbenzohydrazid 24 entstehen bei der Aufarbeitung des Belichtungsansatzes aus 1a in reinem Acetylchlorid. Weiterhin werden die Photolysen von 1b, c in Aceton und von 1b oder 6 b in Methanol beschrieben. Die Bildungsweisen der isolierten Produkte werden diskutiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120514
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  • 10
    Electronic Resource
    Electronic Resource
    Neue thermische Cycloadditionen eines Thieno[3,4-c]isothiazols an Alkine und Alkene (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 266-280 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Thermal Cycloaddition Reactions of a Thieno[3,4-c]isothiazole to Alkynes and AlkenesThe novel triphenylthieno[3,4-c]isothiazole 1 contains two masked 1,3-dipolar systems - a thiocarbonyl imine and a thiocarbonyl ylide; only the latter is capable of cycloaddition reactions as shown by theoretical considerations and experimental results. Thus, 1 reacts at the thiocarbonyl ylide site of the molecule with dimethyl acetylenedicarboxylate via a non-isolable primary adduct 2 to the benzisothiazole 3a (86%). In the same way, 1 combines with methyl propiolate to give the regioisomeric esters 3b, c in a ratio of 43:57. On the other hand, the reactions of 1 with alkenes proceed without sulfur elimination to form the isolable primary adducts of type 7. The corresponding reactions of 1 with dimethyl maleate, dimethyl fumarate, fumarodinitrile, or N-phenylmaleimide proceed with stereospecific formation of the tetrahydro-4,7-epithio-2,1-benzisothiazoles 7a - f, k, m (table 2). Furthermore, 1 reacts with methyl acrylate to produce the four stereo-and regioisomeric esters 7g-j. The constitutions of the adducts are in agreement with chemical reactions and transformations, their configurations are consistent with NMR data.
    Notes: Das neue Triphenylthieno[3,4-c]isothiazol 1 beinhaltet zwei maskierte 1,3-dipolare Systeme  -  ein Thiocarbonyl-imin und ein Thiocarbonyl-ylid; nur letzteres ist zur Cycloaddition befähigt, wie theoretische Betrachtungen und Experimente lehren. So reagiert 1 locospezifisch an der Thiocarbonyl-ylid-Molekülseite mit Acetylendicarbonsäure-dimethylester über ein nicht-isolierbares Primäraddukt 2 zum Benzisothiazol 3a (86%). In gleicher Weise vereinigt sich 1 mit Propiolsäure-methylester zu den regioisomeren Carbonestern 3b, c im 43:57-Verhältnis. Dagegen kommt es bei den Reaktionen von 1 mit Alkenen nicht zur Schwefel-Abspaltung, die Primäraddukte vom Typ 7 sind isolierbar. Die entsprechenden Umsetzungen von 1 mit Maleinsäure-dimethylester, Fumarsäure-dimethylester, Fumarodinitril bzw. N-Phenylmaleinimid verlaufen stereospezifisch zu den Tetrahydro-4,7-epithio-2,1-benzisothiazolen 7a - f,k,m (Tab. 2). Weiterhin vereinigt sich 1 mit Acrylsäure-methylester zu den vier stereo-und regioisomeren Estern 7g - j. Die Konstitutionen der Addukte sind mit chemischen Abbau-und Überführungsreaktionen, ihre Konfigurationen mit NMR- Daten in Einklang.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120124
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