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81.
The products resulting from the reaction of PVC with sodium benzenethiolate were degraded to 0,3% at 180°C in the solid state and at 160°C in solution in trichlorobenzene. The polyene distribution of the polymers after degradation was studied by both UV-visible and resonance Raman spectroscopies, as a function of the degree of substitution. The results show that there are two types of behaviour: that of the PVC sample prior to the substitution reaction together with the samples modified up to a definite degree of substitution which depends on the starting isotactic content, and that of samples with higher degrees of substitution. The former group exhibits not only a steady improvement in thermal stability but also a preferential formation of polyenes of 7 – 9 double bonds whose concentration decreases with increasing degree of substitution. Conversely, for the second group of samples the thermal stability decreases with the degree of substitution and no specific absorption bands are observed. On the basis of earlier work on the selective substitution of the isotactic GTTG and heterotactic TTTG triads during the first stage of the reaction, the present results show that the bands at 393, 416, and 437 nm are related to specific polyenes which result from initiation by the above quoted conformations in PVC, a conclusion for which confirmatory evidence was obtained by resonance Raman spectroscopic examination of the samples. There is, therefore, clear evidence for the occurrence of two distinct degradation mechanisms, one involving initiation by the unstable triad conformations and the other via random initiation at stable and normal structures. To this may be added the initiation by defect structures, which have been extensively documented in the literature.  相似文献   
82.
The OPA1 gene, encoding a dynamin-related GTPase that plays a role in mitochondrial biogenesis, is implicated in most cases of autosomal dominant optic atrophy (ADOA). Sixty-nine pathogenic OPA1 mutations have been reported so far. Most of these are truncating mutations located in the GTPase domain coding region (exons 8-16) and at the 3'-end (exons 27-28). We screened 44 patients with typical ADOA using PCR-sequencing. We also tested 20 sporadic cases of bilateral optic atrophy compatible with ADOA. Of the 18 OPA1 mutations found, 14 have never been previously reported. The novel mutations include one nonsense mutation, 3 missense mutations, 6 deletions, one insertion and 3 exon-skipping mutations. Two of these are de novo mutations, which were found in 2 patients with sporadic optic atrophy. The recurrent c.2708_2711delTTAG mutation was found in 2 patients with a severe congenital presentation of the disease. These results suggest that screening for OPA1 gene mutations may be useful for patients with optic atrophy who have no affected relatives, or when the presentation of the disease is atypical as in the case of early onset optic atrophy.  相似文献   
83.
An in vivo model of liver hyperplastic noduligenesis was inducedin rats by long-term administration of thioacetamide (TAM) (50mg/kg/day i.p.). Three doses of 50 mg/kg of an antitumoral Rh(III)complex were administered at 14, 9 and 5 days before the endof TAM treatment. Plasma and urine were obtained from eitherTAM or Rh(III) complex or TAM plus Rh(III) complex treated ratsto determine the interactions of both substances with the biochemicalparameters related to liver function. The rise in alkaline phosphatase(ALP), teucine aminopeptidase (LAP), -gtutamyl transferase (GGT)and the unchanged activities in the aspartate and alanine aminotransferases(AST, ALT) in plasma of TAM-treated rats indicated that thedisease induced by this substance can be considered as a chronicobstructive biliary disease with indices of cell proliferationand tumors. The increased concentration of bilirubin both inthe plasma and urine of TAM-treated rats suggested liver cholestasisand hepatobiliary obstruction. The very low values of creatinineclearance indicated that there was some degree of kidney failuredue to the effect of TAM. The increased concentration of ammoniaboth in plasma and urine were probably a consequence of thedecreased flux in the urea cycle in the liver. The Rh(III) complexalone did not produce significant changes in the plasma enzymeactivities. The only significant changes were found in the concentrationsof uric acid and ammonia in the urine. When the Rh(III) complexwas administered to TAM-treated rats, significant restorationof the following parameters were observed: plasma enzymaticactivities, blood bilirubin and ammonia, uric acid and creatininein the urine and the creatinine clearance. These results suggestthat the altered liver function induced by TAM can be restoredby Rh(III) complex. The mechanisms by which this complex actsto counteract the TAM-induced changes are not yet established.  相似文献   
84.
Background: Zinc is an essential trace element for the normal growth and development of human beings. The main objective was to evaluate the nutritional status of zinc and its association with nutritional indicators in a series of children with chronic diseases. Methods: The prevalence of patients with dietary zinc deficiency or deficit zinc intake (<80% DRI: dietary reference intake) was analyzed through prospective 72 h dietary surveys, and serum zinc deficiency or hypozincemia (≤70 µg/dL in children under 10 years of age in both sexes and in females older than 10 years and <74 μg/dL in males older than 10 years) was measured through atomic absorption spectrophotometry. The participants were classified according to their nutritional status by body mass index (BMI). Results: Mean serum zinc level in obese (87 µg/dL), undernourished (85 µg/dL), and eutrophic children (88 µg/dL) were normal, but in the undernutrition (60% DRI) and eutrophic (67% DRI) groups the mean dietary zinc intake was low compared to that in the obesity group (81% DRI). There were different associations between nutritional parameters, dietary zinc intake, and serum zinc. All patients with hypozincemia had dietary zinc deficiency. Conclusions: In the whole series, 69% of participants showed a zinc intake lower than recommended and might be at high risk of zinc deficiency.  相似文献   
85.
86.
European Journal of Clinical Microbiology & Infectious Diseases - This study determined the carriage rates and antimicrobial resistance (AMR) genes of enterococci from...  相似文献   
87.
Stroke mortality rates in Spain are one of the highest in all of Europe. At the same time, the Murcia region (south-east Spain) shows, for both genders, the highest age-adjusted stroke mortality rates in all of Spain. The earliest available hypertension figure estimations for this area go back to 1981, when a high prevalence combined with an almost nonexistent control was detected. One decade later, updated prevalence estimations of hypertension are presented jointly with their degree of control and their association with other risk factors based on the results of a prevalence survey in a random population sample (n = 3,091). Arterial blood pressure was measured following the MONICA protocol, maintaining a tight quality control on between and within-observer variability. As hypertensive was considered as any person with systolic blood pressure (SBP) 140 mmHg or with diastolic blood pressure (DBP) 90 mmHg or with antihypertensive pharmacological treatment. Detected prevalence rises to 32.3% (CI 95%: 29.1%–35.5%) among males and to 23.7% (CI 95%: 21.4%– 26%) among females, maintaining its level regarding figures observed back in 1981. However, its control has been increased, especially among hypertensive women [from less than 5% in 1981 to 35% (95% CI: 32%–37.8%) at present]. Hypertension is strongly associated to hipercholesterolemia, overweight, obesity and diabetes (p < 0.01). On the contrary, it shows an opposite association with current smoking, higher educational level and leisure time physical activity (p < 0.01). The highest educational level was associated with better hypertension treatment and control. In summary, while hypertension prevalence is stabilized in our population, its control has improved in a measurable but still insufficient way. These results are in accordance with a decreasing trend in stroke mortality registered in the Murcia Region along the last decade.  相似文献   
88.
A common feature of a wide range of language disorders is the tendency to repeat a particular linguistic form-or set of forms-with abnormal frequency. A brief overview is given of the different ways in which disordered language can be repetitive, and the nature of stereotyped and repetitive language is discussed in terms of the reciprocal relationship between frequency of occurrence and productivity. It is argued that measures such as lexical type-token ratio provide only a partial picture of repetitive language, and that linguistic units larger than the word also need to be taken into consideration. An analytical framework incorporating such units is proposed, which is able to characterize and quantify the extent to which a sample of language is repetitive independently of its aetiology. An illustrative analysis is given of a language sample from a brain-damaged adult, and the repetitiveness profiles of four different patients are compared.  相似文献   
89.
90.
The role of interventional radiology for soft tissue sarcomas is only occasionally addressed in the literature. However, different techniques such as embolization, selective chemotherapy, chemoembolization, and acrylic cement osteoplasty can be helpful with the primary tumor, recurrences, and metastases. This article discusses these techniques and their complications in treatment of soft tissue sarcomas.  相似文献   
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