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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Sedimentology 42 (1995), S. 0 
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: The K-Ar system in clay fractions from shallow marine carbonate shelf environments was investigated on silicate fractions (clay minerals, feldspar) separated from 20 Lower Jurassic to Upper Cretaceous sedimentary rocks, deposited in the southern Tethys ocean. The range of lithologies investigated included dolomite and chalk [IR (insoluble residue)〈10%], marl, shale (IR= 70–85%) and sandstone (IR〉90%). The results show that K-bearing clay fractions often have K-Ar ages similar to the suggested age of deposition, which means either supply of land-derived authigenic K-bearing clays or synsedimentary diagenetic authigenesis, or both. This K-Ar synsedimentary signal is recorded in clay fractions from the whole range of studied lithologies and stratigraphic units. Among the clay minerals, the synsedimentary K-Ar signature was recorded and retained in illite/smectite of the 〈2-um and 〈0.2-um fractions. A prominent synsedimentary signature is found in K-feldspars, from shaly and especially from calcareous rocks, which is substantiated by their authigenic origin based on idiomorphic crystal morphology and their limited size distribution (4–10 um). Post-depositional closure of the K-Ar system is indicated by ages up to 15 Ma younger than the stratigraphic age in different lithologies from dispersed localities. A distinct late diagenetic (20–25 Ma younger) event is recorded in the formation of authigenic K-feldspar within Upper Cretaceous chalk and shale. In the IR and 〉10-um fractions the K-Ar ages reflect the contribution of detrital mica and feldspar which accompanies the kaolinite-dominated samples. The overall results differ considerably from K-Ar age patterns observed in deep-sea sediments, a difference which may be connected with the occurrence of brines in these shelf deposits. The findings indicate the potential in the K-Ar dating of fine IR fractions of marine shelf sediments in terms of geochronological-stratigraphic and palaeogeographical aspects as well as in the petrology of clay minerals themselves.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Thermochimica Acta 148 (1989), S. 467-472 
    ISSN: 0040-6031
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European spine journal 5 (1996), S. 183-186 
    ISSN: 1432-0932
    Keywords: Lumbar spine ; Intervertebral foramen ; Distraction ; Compression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The width of the foramen in the lumbar spine is directly related to the position of the vertebrae. In an MRI study the measurements of the cross-sectional area of the neuroforamen of L4/5 and L5/S1 in neutral position, segmental distraction and compression were calculated. Nine cadaver specimens were investigated and the foraminal width of L4/5 and L5/S1 was measured. In both segments of all specimens the foraminal space significantly enlarged under distraction and decreased under compression. In the L4/5 segment the average relative difference between distraction and compression was 27%.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The interpretation of normal and pathological findings of motor evoked potentials obtained by the use of transcranial magnetic stimulation depends on adequate examination technique, including the appropriate positioning of the recording electrodes over the muscle. On the basis of knowing the location of the motor end plate zones in muscles, magnetic stimulation of the motor cortex of 30 healthy adults was performed in order to explore the influence of the position of the surface recording electrodes on potential parameters and to establish the standard location of the recording electrodes over the biceps brachii, medial vastus, anterior tibial and abductor hallucis muscles for diagnostic use in spine disorders. The cortical latencies and peak-to-peak amplitudes of the evoked potentials were analysed by varying the location of the recording electrodes and the stimulus intensities. The latencies were significantly shorter when the different electrode lay more proximally over the muscle belly. Reproducible potentials with sharp negative onset and maximum amplitude were recorded with a separation of 5–7.5 cm between the different electrode, located over the motor end plate area, and the indifferent electrode, located over the distal myotendinous junction. This implies that the parameters of evoked potentials depend on the position and separation distance of the recording electrodes over the muscles and that it is possible to record the potentials using a lower stimulus intensity and, above all, on relaxed muscles, which may prove to be applicable for intraoperative monitoring of the spinal cord using magnetic stimulation. Therefore it is recommended to use the verified motor end plate zone location as a standard marker for the recording of motor evoked potentials for diagnosis of lesions of descending motor pathways.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 27 (1971), S. 1064-1065 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Résumé Le terme de «target period», qui peut se traduire par période-cible, signifie la période de grossesse la plus sensible aux effets nocifs d'un agent tératogène. Le présent travail situe chez le rat la période-cible du tellure entre les 10e et 15e jours de la grossesse.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-2072
    Keywords: Key words Smoking ; Nicotine ; Sternberg paradigm ; Working memory ; ERPs ; P300 ; Serial-probe memory task
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Nicotine has been shown to affect attentional and mnemonic processes. However, whether these effects are due to changes in perceptual and/or motor aspects of the tasks is not at all clear. This study tested the hypothesis that nicotine from cigarette smoking has differential effects on perceptual and motor processes, as reflected by event-related potentials (ERPs) and reaction times (RTs), respectively, and that perceptual effects may be specific to changes in working memory. ERPs, RTs and performance accuracy were recorded from smokers and nonsmokers during a serial-probe recognition memory task in which lists of words or “memory sets” were followed by a probe word that was either in-set or out-of-set. Smokers were tested in a “smoking” and a 12-h “deprived” condition. Smoking-smokers and deprived-smokers exhibited fast RTs to in-set and out-of-set probes relative to a group of nonsmokers. They exhibited even faster RTs when the in-set probe word matched the first or last item in the memory set. Thus, smokers as a group showed enhanced primacy and recency effects suggesting that smoking specifically facilitates processes related to the motor output aspects of working memory. Different effects characterized the electrophysiology. Larger P300s were recorded to in-set compared to out-of-set probes by both subject groups. Smoking smokers exhibited enhanced P300s to both types of probes. When smokers abstained for 12 h (deprived smokers), the differences in P300 amplitude were reduced but not eliminated. Smoking smokers exhibited faster P300 latencies to in-set probes, while deprived smokers showed delayed latencies relative to nonsmokers. Primacy and recency P300 effects characterized nonsmokers and deprived smokers. However, this relationship was reversed in the Smoking condition. These results support the hypotheses that nicotine has distinct effects on memory-related perceptual and motor aspects of working memory. The increase in efficiency of the memory search with nicotine is consistent with the functional role of the cholinergic system in maintaining a state “appropriate for efficient information processing.”
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1569-8041
    Keywords: chemotherapy ; esophageal cancer ; gemcitabine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background:There were approximately 12,500 cases of esophageal carcinoma diagnosed in the US in 1992 and 12,200 deaths. The impact of chemotherapy on patients with metastatic disease is marginal with a median survival of only five months. Gemcitabine (LY188011,2,2,–difluorodeoxycytidine: dFdC), an analog of cytosine arabinoside (ara-C), is a pyrimidine antimetabolite. Gemcitabine has shown interesting clinical activity in initial phase II clinical trials in a variety of malignancies, including the aerodigestive malignancies, squamous-cell carcinoma of the head/neck and both non-small-cell and small-cell lung cancer. Patients and methods:A total of 21 patients with chemotherapy-naïve metastatic esophageal carcinoma were entered. Nineteen patients were evaluable for toxicity and seventeen patients were evaluable for response. Gemcitabine was administered intravenously at 1250 mg/m2 over 30–60 minutes on days 1, 8, and 15 followed by 1 week of rest. This four-week schedule defined a cycle of treatment. Patients may have received a maximum of six cycles. Results:Gemcitabine was well tolerated with minimal non-hematologic toxicity and grade 3–4 anemia, granulocytopenia, and thrombocytopenia occurring in 10.5%, 21%, and 0% of patients, respectively. No responses were seen in the seventeen evaluable patients. Conclusions:At the dose and schedule studied it would appear that gemcitabine has no activity in patients with chemotherapy-naïve esophageal carcinoma.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-2614
    Keywords: Monitoring: carbon dioxide ; end-tidal ; Measurement techniques: capnography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Medicine
    Notes: Abstract This study was designed to assess the accuracy of end-tidalPco 2 and transcutaneousPco 2 as measurements of arterialPco 2 in extubated, spontaneously breathing patients recovering from general anesthesia. In 30 patients, measurement of arterial transcutaneous, and end-tidalPco 2 were taken simultaneously with body temperature approximately every 15 minutes over a 2-hour period. ArterialPco 2 values were corrected for body temperature. Values for Paco 2 were compared with those forPetCO2 and Psco 2 by linear regression analysis and by calculation of bias ± precision. Thirty-six percent of the capnogram tracings obtained did not develop a plateau phase. We found poor correlation between end-tidal and arterialPco 2 regardless of the shape of the capnogram tracing, as well as poor correlation between transcutaneous and arterialPco 2. Although the measurements of bias and precision of noninvasivePco 2 monitors in this population are comparable to studies in other populations, we advise caution in relying on the routine use ofPetCO2 or Psco 2 for the noninvasive assessment of respiratory depression in extubated, spontaneously breathing patients recovering from general anesthesia.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Pediatric surgery international 15 (1999), S. 214-216 
    ISSN: 1437-9813
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Pneumatic reduction of idiopathic intussusception is successful in about 80% of cases, while 60% of the failures are reduced at surgery without resection. To determine whether delayed, repeated attempts at enema reduction of failures would reduce the need for operation in selected cases, over a 2-year period (1994–1996 inclusive), 17 infants with idiopathic intussusception underwent delayed repeat enemas 2–19 h following the first failed attempt at reduction. Clinical parameters and radiologic findings were evaluated with respect to outcome. Ten intussusceptions were successfully reduced after the second attempt in 9 and after the fourth attempt in 1. Seven children underwent a laparotomy, 5 because of failure of progressive reduction at air enema (AE). Two were taken to surgery early in the series, 1 because of perforation during a second attempt and 1 while awaiting a third reduction attempt. The 10 successful reductions all showed progressive movement of the intussusceptum on each AE; the 2 who perforated failed to show progressive reduction on their second AE. Because of these cases, the remaining 5 were referred to surgery because of failure of progressive reduction of the intussusceptum on the second attempt. At laparotomy, of the 7 unsuccessful reductions, 4 required resection and 3 had difficult manual reduction. The presence of vomiting, a mass, and/or bloody stools were not predictors of outcome. Failures had higher body temperatures (38.1 ± 0.3 vs 37.4 ± 0.1 °C, P = 0.07), heart rates (153.7 ± 8 vs 136.9 ± 2.1 min, P = 0.03), and longer duration of symptoms (36.8 ± 4 vs 21.3 ± 3.6 h; P = 0.01) than successes. Delayed repeat AEs may be safe and effective in selected cases of idiopathic intussusception, but should be considered only if significant movement of the intussusceptum is noted at each attempt. The ideal time for repeat AE reduction prior to surgery is not established, but 2–4 h appears appropriate. Pyrexia, tachycardia, and duration of symptoms greater than 36 h are relative contraindications to this course of management.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Pediatric surgery international 13 (1998), S. 411-413 
    ISSN: 1437-9813
    Keywords: Key words Nasogastric decompression ; Pediatrics ; Post-laparotomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of this study was to evaluate the role of nasogastric (NG) decompression after laparotomy in pediatric surgical practice: 94 children who underwent abdominal surgery by a single surgeon were consecutively prospectively managed without postoperative NG tubes. Patients with either bowel obstruction or intra-abdominal infection were excluded from the study. These children were compared with 94 retrospective, matched controls who were routinely managed with postoperative NG decompression by the same surgeon. Data were analyzed with regard to patient, operative, and outcome variables. There was no difference in gender, age (3.8 ± 0.5 vs 3.5 ± 0.4 years, P 〉 0.7), or postoperative complications (P 〉 0.8) between the two groups. However, there was a higher incidence of postoperative vomiting (22% vs 11%, P 〉 0.05) in the children who did not have postoperative NG decompression. Nevertheless, a significant decrease in time to first feed, first stool, and discharge was noted in the group of patients managed without NG tubes (P 〈 0.05). NG decompression thus need not be routinely used in the pediatric patient undergoing abdominal surgery, as there is no difference in postoperative complications and the hospital stay is shortened.
    Type of Medium: Electronic Resource
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