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The carbonization process of a Si(111) 7×7 reconstructed surface exposed to acetylene (C 2 H 2 ) has been investigated by combining several structural, electronic, and luminescence techniques. The aim was to give a comprehensive scenario of the different carbonaceous phases formed on the clean silicon surface starting from the C 2 H 2 molecule chemisorbed at room temperature up to the formation of a crystalline c-SiC compound. We found that the molecule breaks at about 450°C and for temperatures up to 600°C a Si 1− x C x alloy is formed inside the sample. For higher temperatures, up to 850°C, c-SiC crystallite precipitation epitaxially grown on the Si surface is observed. The near-edge-energy loss spectra at the carbon K edge ensures that for C 2 H 2 deposition temperatures higher than 600°C the carbon bonds are sp 3 -like, thus demonstrating the absence of non-substitutional carbon concentration. The luminescence spectra performed at each stage of carbonization revealed the formation of well-defined Si 1− x C x phases (with x of a few percent) and clearly demonstrate that the exposure to C 2 H 2 is a highly efficient method to change in a continuous way the near-infrared optical properties of silicon surfaces in the spectral range from 0.9 to 1.1 eV.

Poly ( l -lactide) (PLLA) with molecular weight ranging from 7600 to 700 000 has been purified from traces of residual metals and has then undergone thermal behaviour examination. The PLLA decomposition temperature obtained by thermogravimetric analysis was used as a measure of its thermal stability. It has been demonstrated that residual low molecular weight compounds such as moisture, lactic acid, lactide, etc. associated with PLLA can be removed without affecting the polymer thermal stability, while residual metals were revealed to be the principal parameter which causes drastic thermal degradative effect on the polymer. The decomposition temperature of pure PLLA at infinite molecular weight was 353°C. The thermal stability of PLLA has been studied as a function of the amount of added tin, zinc, aluminium and iron. Experimental results enable the comparison of their influence on PLLA thermal stability which follows a decreasing order: Fe > Al > Zn > Sn. The more selective the catalyst for PLLA polymerization, the less efficient is its depolymerization effect at high temperature.

Currently, evidence-based medicine indicates that epidural analgesia (EA) labor is not associated with cesarean and instrumental delivery for dystocia. This evidence was obtained from clinical investigations of variability in clinical labor management. An optimized balance between anesthesiological and obstetric practice is vitally important for securing spontaneous delivery. The total dose of local anesthetic for EA may be associated with operative delivery when there is a lack of obstetric care standardization and co-interventions reducing unintended EA effects. Furthermore, combining local anesthetic low dose and opioid low dose may produce a new balance with obstetric management. Physiological and pharmacological knowledge together with recent clinical findings suggest that combined opioid-local anesthetic low dose EA causes minimal negative effects on labor progress and is effective and safe in terms of maternal and neonatal outcome. Internal communication between obstetricians and anesthesiologists is essential for optimizing EA labor management. Processes of health care quality management, such as medical audit and peer review, should be routinely practiced to reach this goal.

Subjects in spinal anaesthesia have been reported to show a decrease in the level of alertness, even when they have not received any sedative drugs.of this study is to verify, in caesarean delivery if the bupivacaine subarachnoid anaesthesia, with or without intrathecal fentanyl dose, produces a sedative effect, to define the entity and to identify the mechanism that most likely causes it.The clinical investigation is divided into Part I (non-randomized trial) and Part II (randomized trial) and is set in the University hospital's delivery-unit. Part I: 45 pregnant women were recruited and enrolled in 3 groups: women having natural delivery (n=15), women receiving caesarean delivery with subarachnoid anaesthesia (n=15) and with general anaesthesia (n=15). Self-rating depression scale (SDS), self-rating anxiety scale (SAS), state anxiety inventory (SAI) and trait anxiety inventory (TAI) psychometric tests were patient-completed for pre-delivery anxiety evaluation. Part II: 23 pregnant women undergoing caesarean delivery were single-blind randomized to receive subarachnoid anaesthesia with single 12.75 mg 0.5% hyperbaric bupivacaine (n=10) or with 12.75 microg 0.5% hyperbaric bupivacaine and 15 mg fentanyl (n=13). Bispectral index (BIS), observer's assessment of alertness/sedation (OAA/S) scale, self-sedation visual analogic scale (VAS) and mean arterial pressure (MAP) were perioperatively monitored.Part I: it was found, using SAI, a higher level of state anxiety in the pregnant women undergoing caesarean delivery than those having natural delivery (p0.05). Part II: pregnant women receiving subarachnoid anaesthesia for caesarean delivery had a decrease of the level of alertness from 10 to 70 min after the execution of lumbar puncture (p0.05), with a sedative peak from 35 to 45 min (p0.01), as measured by OAA/S scale and self-sedation VAS but not by BIS. Women who received bupivacaine-fentanyl spinal anaesthesia had a more consistent sedative effect from 35 to 70 min (p0.05).Pregnant women undergoing caesarean delivery had a more elevated level of state anxiety, assessed by SAI, as seen in Part I. Subarachnoid anaesthesia in caesarean delivery is associated with a reduction of alertness level. A double mechanism might cause a clinically valuable sedative effect, observed by OAA/S scale and self-sedation VAS: decrease of the afferent spinal inputs and an anxiolytic psychophysiologic effect, induced by good outcome of the birth and mother-baby contact. Intrathecal bupivacaine-fentanyl dose produces a larger alertness decrease than single bupivacaine, because the anaesthetic block density increases. BIS was not a sensitive measure to detect the light sedation occurring in Part II of this study.

Verify correspondence and compare percentage body fat (%BF) estimates by skinfold thickness (SKT), bioelectrical impedance analysis (BIA) and DEXA. Twenty voluntaries women (aged 62-79 yr) were assessed. The body fat was estimated using two different equations of SKT(Jackson (19); Durning and Womersley, (20)), BIA using two-predictions formulas (23) and DEXA. To compare mean values of %BF was used analysis of variance for repeated measures (ANOVA--Bonferroni), the correlation of the inter-method was verified by Pearson correlation coefficients (r), and correspondence between prediction formulas was tested by using the approach by Bland and Altman (25). The %BF assessed by BIA (23) shown poor correlation (r0.5) with two SKT equations. The %BF ranged from 31.5 +/- 5.5 to 41.2 +/- 6.1 (mean +/- SD) for Jackson (19) e DEXA, respectively. The analysis of variance shown no significant differences (p0.05) between methods and/or equations by BIA (RJL-CompCorp) vs. DC-Jackson (19). There were observed significant differences (p0.001) between all comparisons. The correspondence between RJL-CompCorp vs. Deurenberg (23) was good and the same was observed for DEXA vs. Durning and Womersley (20). Although the methods and/or equations used in this study have been commonly utilized to estimate BF in elderly subjects, they neither must be used as a standard method. Each method has limitations and the comparison can be useful for interpretation of results.

A solitary late recurrence of renal cell carcinoma is very unusual. A case of triple pancreatic metastases of renal carcinoma is presented in a male patient who 9 years previously had undergone left radical nephrectomy. Although there are no specific signs, arteriography, computed tomography and intraoperative ultrasonography can give additional information to detect this rare localization. Surgical resection, when possible, is the most useful treatment for this metastatic lesion.

Seventeen preoperative variables were collected in order to assess their prognostic value on survival in 82 cirrhotic patients who underwent a portosystemic shunt for ruptured esophageal varices. Univariate analysis showed that the presence of encephalopathy, bad nutritional status, elevated serum bilirubin, low serum albumin, the presence of ascites and Child-Turcotte's or Child-Pugh's C class were significantly associated with a reduction of long-term survival. Multivariate analysis according to the Cox model showed that only encephalopathy and nutritional status were independently associated with survival. Six survival curves were proposed to estimate the survival probability with these 2 preoperative data; encephalopathy had a predominant effect on survival during the first 5 years after surgery.

Encephalopathy is the most common complication after total portal by-pass operation. 5-15% of patients have severe and intractable encephalopathy. Many medical and surgical procedures were proposed to prevent and treat this complication but none of these were effective. Two cases of patients with severe encephalopathy after side to side portal by-pass are presented. They were treated with the procedure proposed by Bismuth; it consists of a gradual suppression of the anastomosis associated with esophagogastric devascularization. In the first case we obtained the regression of encephalopathy while the second patient died portal thrombosis (probably due to this procedure) two months after surgery. Validity and efficacy of this procedure must be evaluated with a higher number of patients. This surgical technique should lead to choose the type of portal by-pass: side to side portal by-pass operation allows according to Bismuth's procedure to reestablish an hepatopetal flow.

Insulin resistance in liver cirrhosis may depend on either reduced sensitivity (receptor defect) and/or reduced response to insulin (postreceptor defect). To clarify the mechanism of such resistance, a [3H]glucose infusion (0.2 microCi/min) was performed for 120 min before and during a euglycemic clamp at approximately 100, 1,000, and 10,000 microU/ml steady state plasma insulin concentration in 18 compensated cirrhotics with portal hypertension and impaired glucose tolerance, and 18 healthy volunteers with no family history of diabetes, matched for sex, age, and weight. Mean fasting plasma insulin (29.2 +/- 3.4 SEM vs. 14.8 +/- 1.1 microU/ml) was significantly higher (P less than 0.001) in cirrhotics, while fasting plasma glucose was much the same in the two groups. Glucose use (milligrams per kilogram per minute) was significantly lower in cirrhotics at all three steady state plasma insulin levels: 3.04 +/- 0.34 vs. 7.72 +/- 0.61 (P less than 0.001) at approximately 100; 6.05 +/- 1.07 vs. 11.45 +/- 1.24 (P less than 0.001) at approximately 1,000; and 11.69 +/- 0.69 vs. 14.13 +/- 0.74 (P less than 0.05) at approximately 10,000 microU/ml. Mean plasma C-peptide was significantly higher in cirrhotics both basally and during the steady states (P less than 0.001); it was completely suppressed at approximately 10,000 microU/ml in controls and only 57.5% of the baseline in cirrhotics. Endogenous glucose production (milligrams per kilogram per minute) was much the same in the two groups in the fasting state and almost entirely suppressed in the controls (0.10 +/- 0.05 vs. 0.48 +/- 0.11, P less than 0.001) at approximately 100 microU/ml; at approximately 1,000 microU/ml a residual glucose production, 0.07 +/- 0.05, was observed in the cirrhotics only. In addition, insulin binding and 3-ortho-methyl-glucose transport were studied in vitro in six cirrhotics and six controls. Insulin binding to circulating monocytes and isolated adipocytes was significantly lower (P less than 0.025) in cirrhotics in all insulin concentration studies. Glucose transport values on isolated adipocytes were significantly lower in cirrhotics both basally (P less than 0.001) and at maximal insulin concentration (P less than 0.05). These results suggest that insulin resistance in human cirrhosis is more dependent on depressed peripheral glucose use than on increased endogenous glucose production, and that a combined receptor and postreceptor defect in insulin action on target cells seems to be present.

Sixteen gastrectomized patients underwent surgical treatment for alkaline reflux gastritis by means of a Roux-en-Y loop duodenal diversion. Long-term evaluation of results was performed 5-9 years later. Ten patients (62.5%) showed good results, with absence of digestive symptoms and with an increase in body weight. Two patients (12.5%) had moderate results, with presence of sporadic and mild epigastric pain. Four patients (25%) had unsatisfactory results, with persistence of epigastric pain and absence of body weight increase. No patient had recurrent biliary vomiting or endoscopic evidence of endogastric biliary reflux. Among the six patients with moderate and unsatisfactory results, two had a significant alcoholic intake, two showed a high degree of anxiety on psychological assessment, and two had both factors. Alcoholism and psychological disturbances should be considered exclusion criteria when evaluating a gastrectomized patient for surgical cure of alkaline reflux gastritis.

A 60-yr old Italian woman presented with repeated gastrointestinal hemorrhages due to ruptured esophageal varices. No evidence of liver disease could be demonstrated by laboratory tests or by multiple liver biopsies. Angiography revealed a patent portal trunk and the presence of esophageal varices. A side-to-side portacaval shunt was performed, which caused the disappearance of the esophageal varices. There was no recurrent digestive hemorrhage during a 24-month follow-up. A mild deterioration of liver function was demonstrated by laboratory data 16 months after surgical operation and some mild episodes of hepatic encephalopathy occurred. This case can be considered an example of idiopathic portal hypertension, a rare pathological condition with a higher prevalence in certain geographical areas. Its etiology is not known. One important aspect of this entity is its potential to evaluate the effects of surgical portacaval shunt procedure in the absence of liver damage.

Mortality due to recurrent variceal esophageal bleeding secondary to portosystemic shunt thrombosis is high. Early diagnosis of shunt thrombosis is therefore necessary. For these reasons, patients who have undergone a portal diversion must be controlled periodically. To this end, frequent controls, using reliable, riskless and inexpensive methods are needed. In this work, 34 patients who underwent different types of portal systemic shunts were studied by ultrasonography. Diagnosis by ultrasonography (confirmed by radiography showing esophageal varices and sometimes by arteriography) was positive with direct vision of the anastomosis in 65 p. 100 of cases and with indirect signs of patency or thrombosis of the anastomosis in 32 p. 100 of cases. This method failed to conclude in 3 p. 100 of our cases.

Indications for and results of bilio-digestive shunt are discussed and basic stages described. The data refer to non-cancerous pathology of the bile ways. It is concluded that the operation should always be carried out in the first instance (comparatively high intracholedochic pressure values, moderate dilatation of the main bile way, calculosis of the papilla) and not just at reoperation. This convinction is backed up by the very low operative mortality, the good long-term results and the operation's comparatively easy performance.

Gastric pH was monitored, by means of a computerized system, in healthy controls (C) and in patients with active duodenal ulcer (ADU) and inactive duodenal ulcer (IDU). The test was performed before treatment and during administration of a single dose of ranitidine 150 mg, cimetidine 400 mg, and pirenzepine 50 mg, in random sequence at 12-h intervals, (10 am, 10 pm). Under basal conditions, progressively lower median pH values were detected in ADU and IDU patients, compared with controls. A significant difference was found between C and ADU during daytime (1.38 vs. 0.85), nighttime (1.29 vs. 0.81), and 24 h (1.35 vs. 0.81) and between C and IDU during 24 h (1.35 vs. 1.11). However, no statistical difference was observed between patients with active and inactive ulcer disease. Administration of ranitidine and cimetidine significantly increased gastric pH during nighttime but not during daytime. Ranitidine, at the doses studied, proved to be more potent than cimetidine in suppressing gastric acidity. Gastric pH was unaffected by pirenzepine in most cases.