Optical properties of a conjugated-polymer-sensitised solar cell: the effect of interfacial structure.

Dye-sensitised solar cells (DSSCs) have sparked considerable interest over two decades. Recently, a method of polymer-wire sensitisation was demonstrated; the polymer is suggested to form a hole transport pathway (wire) following initial charge separation. We predict the optical properties of this polymer in various interfacial configurations, including the effects of chain length and attachment to {100} or {101} TiO2 facets. Contrary to most DSSCs, the {100} facet model best describes the experimental spectrum, predicting a relative thickness of 5.7 ± 0.2 µm, although {101} attachment, if implemented, may improve collection efficiency. Long chains are optimal, and stable attachment sites show minimal differences to absorbance in the major solar emission (visible) band. Combinations of {100}, {101}, and pseudo-bulk TiO2 models in three-parameter fits to experiment confirm the relative importance of the {100} facet.

Tailoring highly conductive graphene nanoribbons from small polycyclic aromatic hydrocarbons: a computational study.

Pyrene, the smallest two-dimensional mesh of aromatic rings, with various terminal thiol substitutions, has been considered as a potential molecular interconnect. Charge transport through two terminal devices has been modeled using density functional theory (with and without self interaction correction) and the non-equilibrium Green's function method. A tetra-substituted pyrene, with dual thiol terminal groups at opposite ends, has been identified as an excellent candidate, owing to its high conductance, virtually independent of bias voltage. The two possible extensions of its motif generate two series of graphene nanoribbons, with zigzag and armchair edges and with semimetallic and semiconducting electron band structure, respectively. The effects related to the wire length and the bias voltage on the charge transport have been investigated for both sets. The conductance of the nanoribbons with a zigzag edge does not show either length or voltage dependence, owing to an almost perfect electron transmission with a continuum of conducting channels. In contrast, for the armchair nanoribbons a slow exponential attenuation of the conductance with the length has been found, due to their semiconducting nature.

Comparison of the efficacy of 250 mg and 500 mg clarithromycin used with lansoprazole and amoxicillin in eradication regimens for Helicobacter pylori infection.

AIMS AND METHODS: The aim of this study was to compare the efficacy of 250 mg and 500 mg clarithromycin used with lansoprazole and amoxicillin in eradication of H. pylori infection. 235 patients with H. pylori infections and non-ulcer dyspepsia were randomly assigned to one of the following regimens: lansoprazole 30 mg, amoxicillin 1000 mg, clarithromycin 250 mg (LAC250) and lansoprazole 30 mg, amoxicillin 1000 mg, clarithromycin 500 mg (LAC500). All drugs were given twice daily for 7 days. The patients were assessed for prevalence of H. pylori with the CLO test. Gastric biopsy samples obtained during upper gastrointestinal endoscopy before randomization and 4-6 weeks after completion of therapy were used for histology and culture. Bacterial sensitivity to clarithromycin and amoxicillin was determined with the E-test. RESULTS: 101 patients in the LAC250 mg group and 102 in the LAC500 group completed the study. On intention-to-treat analysis, eradication rates were 81% with LAC250 and 82% with LAC500 (p=0.88). On per-protocol analysis, eradication rates were 92% with LAC250 and 96% with LAC500 (p=0.23). Among the 203 patients (86% of the entire study group) for whom H. pylori antibiotic-sensitivity testing was technically feasible, primary resistance to clarithromycin was found in 9% and to amoxicillin in 0%. Eradication of clarithromycin sensitive/resistant strains was 94%/38% for LAC250 (p < 0.001) and 93%/40% for LAC500 (p < 0.001). CONCLUSIONS: The cure rates for the two regimens were similar, although adverse effects were more frequent with the LAC500 regimen, suggesting that 250 mg of clarithromycin b.d. may be sufficient in our patient population.

Epidemiology of irritable bowel syndrome in Croatia.

This epidemiological study of irritable bowel syndrome (IBS) was the first one of the type in Croatia. The aim of the study was to determine prevalence and association between IBS and gender, age, education and urban/rural living. Study design included a questionnaire based on Rome criteria, which was send to 500 study subjects by post. Study population matched the adult population of Croatia according last census. Study result showed a high prevalence of IBS: i.e. 28% (10% of males and 18% of females). Age, education and urban/rural type of living were not related to the prevalence of IBS. Logistic regression gave gender-body mass index (BMI) model for IBS determination: the relative risk for getting IBS in females was by 165% higher than in males and BMI increase of 5 kg/m2 increased the risk of IBS by 36%. BMI was indicated as a possible new factor of IBS prevalence.

Efficiency of biofeedback therapy for chronic constipation in children.

Chronic constipation is a common disorder in childhood. The underlying mechanisms responsible for chronic constipation remain unknown. Conventional methods of treatment often fail to produce satisfactory results. Favorable effects of biofeedback treatment for constipation have been suggested, however, with variable results reported in the literature. The main aim of the study was to evaluate biofeedback versus conventional therapeutic protocol in the treatment of chronic constipation over a short period of time (3 months). Forty-nine children with chronic idiopathic constipation, 24 allocated to conventional and 25 to biofeedback therapy were included in the study. Thorough history data on bowel function and symptoms, anorectal status and manometric testing were collected before and after treatment. Follow up consisted of a structured interview. Mean age was 94 and 92 months in the children treated by the conventional and biofeedback method, respectively. The initial prevalence of abnormal defecation dynamics was 58% and 56% in the group children allocated to conventional and biofeedback therapy, respectively. The difference was not statistically significant. After the treatment, the values of rectal sensation threshold, critical volume, and recto-anal inhibitory reflex volume were significantly higher, and the prevalence of abnormal defecation dynamics was significantly lower in the group on biofeedback therapy. Biofeedback is an effective method of treatment for chronic constipation in children in short term. Therapeutic results are especially favorable in the recovery of abnormal anorectal dynamics and manometric parameters. There is no clear evidence for long-term benefits of biofeedback therapy.

Effect of Helicobacter pylori eradication on extent of duodenal gastric metaplasia and grade of gastritis.

The extent of the regression of duodenal gastric metaplasia (DGM) after the eradication of Helicobacter pylori infection is controversial. Therefore, we decided to assess the degree of DGM before, sex weeks and one year after H. pylori eradication. 105 consecutive Helicobacter pylori positive patients with endoscopically proven duodenal ulcer, with DGM and Helicobacter pylori infection were recruited for this study. The diagnosis of Helicobacter pylori infection was based on CLO-test and histology, and DGM was assessed on four bulb biopsies taken before, sex weeks and one year after Helicobacter pylori eradication. Histological assessment of Helicobacter pylori associated gastritis was performed according to the Sydney classification. Follow up study on 98 patients before, six weeks and one year after the eradication of Helicobacter pylori showed that the mean extent of DGM did not change significantly after eradication and did not differ when compared with 14 patients with persisting infection. Our results show that the inflammatory process related to Helicobacter pylori does not play the main role in the development of DGM.

Relationship of gastric metaplasia and age, sex, smoking and Helicobacter pylori infection in patients with duodenal ulcer and duodenitis.

Gastric metaplasia is one of the factors in duodenal ulcer appearance. The aim of this study was to investigate the frequency of gastric metaplasia and its connection with age, sex, cigarette smoking and H. pylori infection. In the study 216 patients were included. There were 98 patients with duodenal ulcer, 60 with duodenitis, and 58 healthy control subjects. There was no statistically significant difference in gastric metaplasia frequency according to age and sex. Gastric metaplasia was statistically more significant in patients with duodenal ulcer (p < 0.01). In all the subjects cigarette smoking did not significantly influence gastric metaplasia. In smokers with duodenal ulcer, and those who besides duodenal ulcer and smoking had H. pylori infection gastric metaplasia was more frequent (p < 0.01). However, in patients with duodenal ulcer, there was no statistically significant difference of gastric metaplasia related to H. pylori presence. It may be suggested that H. pylori infection is not of indispensable significance for gastric metaplasia appearance.

Evaluation of the Olympus AU 400 clinical chemistry analyzer.

The performance of the Olympus AU 400 clinical chemistry analyzer was evaluated according to the guidelines of the European Committee for Clinical Laboratory Standards. The following analytes were tested: glucose, urea, creatinine, calcium, AST, ALT, CK, LDH, ALP and amylase. The Olympus AU 400 was compared with the Olympus AU 800. Coefficients of correlation showed high correlation between the compared analyzers. Other performances (intra- and inter-assay variation, carry-over and interferences) of the analyzer were satisfactory.

Features of uremic neuropathy in long-term dialysis.

In order to assess the influence of long term hemodialysis on progression of uraemic neuropathy (UN), 16 different electroneurographic (ENG) parameters on 158 dialysis patients were performed. The ENG parameters were compared in three groups of patients of different dialysis age. Group I: high dialysis age (HDA) comprising of, 31 patients being more than 10 years on dialysis; Group II: intermediate dialysis age (IDA) comprising of 53 patients between 5 and 10 years on HD and group III: low dialysis age (LDA) comprising of 74 patients being less than 5 years on dialysis. The influence of sex and age was also analyzed. All sixteen tested parameters were altered in uremic patients when compared to 140 healthy controls (p < 0.01). HDA pts compared to LDA pts and the older group versus the younger had 11 and 9 out of 16 ENG parameters significantly worsened, respectively (p < 0.01). The most profound and reproducible lesion was in prolongation of evoked potential of tibialis posterior and peroneus nerve (FWt, HWt, FWp). HDA, especially after 10 yrs and the age but not the sex is clearly associated with a further progression of UN. However, for unknown reasons, the progression of UN in dialyzed patients is not followed by a parallel worsening of clinical symptoms (p > 0.05).

Effects of smoking and Helicobacter pylori on prostaglandin concentrations in gastric and duodenal mucosa of patients with duodenal ulcer and duodenitis.

The aim of this study was to determine the level of endogenous prostaglandin E2 (PGE2), prostaglandin F1 alpha (6-keto-PGF1 alpha) and thromboxane B2 (TXB2) in the gastric and duodenal mucosa of patients with duodenal ulcer and duodenitis. Besides, the investigation aimed at determining the effect of smoking and infection by Helicobater pylori on prostaglandin synthesis. The investigation comprised 62 patients with duodenal ulcer, 46 patients with duodenitis and 44 controls. The results of our investigation indicate that the decreased prostaglandin synthesis in gastric and duodenal mucosa determined in patients with duodenal ulcer may have a considerable role in development of duodenal ulcer. Furthermore, the harmful effects of smoking on the gastric and duodenal mucosa may be mediated by the decreased prostaglandin synthesis in the gastric and duodenal mucosa. However, Helicobacter pylori seems to affect the development of duodenal ulcer through other mechanisms.

[Comparative study of the occurrence of gastrointestinal side-effects of tenoxicam and other nonsteroidal antirheumatic agents in patients with rheumatoid arthritis]. / Komparativno istrazivanje ucestalosti gastrointestinalnih nuspojava tenoksikama i ostalih nesteroidnih antireumatika u bolesnika s reumatoidnim artritisom.

This research tries to determine the difference between granular tenoxicam (Tilcotil Roche) and other non-steroidal antiinflammatory drugs administered to patients with rheumatoid arthritis. The research comprised 143 patients with rheumatoid arthritis divided in two groups (71 + 72). As regards patients with rheumatoid arthritis, granular tenoxicam of a twenty-miligram dose daily showed both a good clinical effectiveness and a good bearing in long-term medicine taking, rarely causing gastrointestinal side effects, compared to other nonsteroidal antiinflammatory drugs in peroral taking.

Ketoconazole inhibits acetaminophen-induced hepatotoxicity in mice.

OBJECTIVE: To investigate the effect of ketoconazole on acetaminophen (AAP)-induced hepatotoxicity in mice. MATERIALS AND METHODS: Mice were given AAP intragastrically (300 mg/kg) and treated with ketoconazole (100 mg/kg intraperitoneally) or saline either 30 min before or 2-3 h after AAP administration. Mortality was recorded for 48 h, during which all mice given saline either died or recovered fully. Serum alanine and aspartate transaminase levels were determined 24 h after administration of AAP. Prostaglandin E2, thromboxane A2 and leukotriene C4 production was determined 6 h after AAP administration in the supernatants from the short-term culture of liver fragments by radioimmunoassay. RESULTS: Ketoconazole significantly decreased mortality and transaminase levels when given to mice either 30 min before or 2 h after AAP. Liver fragments from mice with AAP hepatitis produced greater quantities of prostaglandin E2, thromboxane A2 and leukotriene C4 than fragments from normal liver. Pretreatment of mice with ketoconazole or its addition to liver fragments ex vivo further increased the production of prostaglandin E2 and reduced the production of thromboxane A2. The effect of ketoconazole on leukotriene C4 synthesis was different in vivo (synthesis stimulation) from in vitro (synthesis inhibition). CONCLUSION: The protective effect of ketoconazole in AAP hepatitis is most probably mediated by modulation of eicosanoid synthesis by liver cells.

[The effect of pregnancy on the course of ankylosing spondylitis]. / Utjecaj trudnoce na tijek ankilozantnog spondilitisa.

Twenty-five of our patients were married women (71.4 percent), 23 had given birth once or twice and 20 of our patients gave birth after the onset of the disease. The average age at the time of the analysis was 34 years. The course of the disease showed exacerbation once or twice in the course of pregnancy in most of our patients. Improvement of their condition was seen in 11 patients with a duration of approximately 5.4 months on the average and in individual cases even for a duration of 7 or 8 months. Remission during the puerperium period lasted somewhat over 4 months in only 2 of our patients. Pregnancy and the puerperium had no significant effect on the course of the disease.

Diuretics vs. paracentesis followed by diuretics in cirrhosis: effect on ascites opsonic activity and immunoglobulin and complement concentrations.

Ascitic fluid opsonic activity and ascitic fluid C3 concentrations are important protective factors against spontaneous bacterial peritonitis. This randomized controlled study was performed to compare the effect of diuretic administration alone vs. single large-volume therapeutic paracentesis followed by administration of diuretics on ascitic fluid opsonic activity and on ascites and serum immunoglobulin and complement concentrations in patients with alcoholic cirrhosis and tense ascites. Twenty-one patients were randomly allocated to two groups: group 1 included 11 patients who were treated with diuretics alone, and group 2 included 10 patients who were treated with single large-volume therapeutic paracentesis (5 to 6 L of ascites removed) followed by diuretics. Ascitic fluid opsonic activity and serum and ascites immunoglobulin and complement concentrations were measured at the beginning and at the end of treatment. The ascitic fluid opsonic activity increased significantly in patients treated with diuretics alone (p < 0.05), whereas in the group of patients treated with therapeutic paracentesis followed by diuretics, the ascites opsonic activity remained stable. Although ascitic fluid IgG, IgA and C3 concentrations increased significantly in patients treated with diuretics alone (p < 0.05), ascitic fluid C3 concentration significantly decreased in patients from group 2 (p < 0.05), whereas IgG and IgA concentrations remained unchanged. However, in both groups of patients serum immunoglobulin and complement concentrations remained unchanged. This study suggests that in cirrhotic patients with tense ascites, treatment with diuretics alone may have the potential advantage over single large-volume therapeutic paracentesis followed by the administration of diuretics of providing better protection from spontaneous bacterial peritonitis.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of interleukin 1 alpha on acetaminophen-induced hepatotoxicity.

The protective effect of interleukin 1 alpha (IL-1 alpha) in mice with acetaminophen (AAP)-induced hepatitis was investigated. IL-1 alpha had a significant protective effect if given 2 or more hours (up to 24 hours) before AAP; it significantly reduced mortality of mice and decreased serum transaminase level. The maximal effect was obtained with the dose of 1000 U (166 ng/kg) IL-1 alpha. Pretreatment with IL-1 significantly increased the synthesis of prostaglandin E2 (PGE2) in samples of liver tissue from AAP-treated mice, but had no effect on the synthesis of leukotriene C4 (LTC4). Pretreatment with indomethacin (IMC) did not abrogate significantly the protective effect of IL-1. Thus, the hepatoprotective effect of IL-1 alpha can not be entirely explained by the stimulation of prostaglandin (PG) synthesis.

Short report: effect of ranitidine on duodenal ulcer healing in patients with cirrhosis of the liver.

The effect of ranitidine (300 mg daily) on the healing of acute duodenal ulcer was investigated in patients with and without cirrhosis of the liver. Of the 109 patients who entered the study, two patients from each group were excluded. Healing rates after 4 and 8 weeks were significantly different between patients with cirrhosis and controls (4- and 8-week healing rates in cirrhotics and non-cirrhotics: 49 and 69%, and 71 and 91%, respectively). This study demonstrates that duodenal ulcer healing is delayed in patients with cirrhosis.

Inflamed pancreatic pseudocyst: optimization of pseudocyst fluid culture technique.

A serious complication of pancreatitis, inflamed pseudocyst is associated with considerable morbidity and relatively high mortality rate. In this study chronic pancreatic pseudocyst fluid was cultured by the conventional method as well as by a method of bedside inoculation of blood culture bottles with pseudocyst fluid. The conventional method grew bacteria in only 26 (65%) of 40 patients with chronic pancreatic pseudocyst, whereas the blood culture bottles grew bacteria in 38 (95%) patients (p < 0.001). The blood culture bottle method also resulted in more rapid detection of bacterial growth (p < 0.001). Inoculation of pseudocyst fluid into the blood culture method seems more sensitive than the conventional method in detecting inflamed pancreatic pseudocyst probably due to the low pseudocyst concentration of bacteria observed in this study.

Effect of verapamil on portal blood flow in patients with liver cirrhosis.

The effect of acute (80 mg orally) and prolonged (240 mg orally daily for 2 weeks) verapamil administration on portal blood flow was studied in 12 patients with histologically proved alcoholic liver cirrhosis. Portal hemodynamics were examined by the ultrasonic duplex Doppler system. Thirty minutes after acute verapamil administration, the following parameters remained unchanged: (1) cross-sectional area of the portal vein, from 1.52 +/- 0.41 to 1.51 +/- 0.43 cm2; (2) portal blood velocity, from 13.2 +/- 1.6 to 13.4 +/- 1.6 cm/s; (3) estimated volume of portal blood flow, from 931 +/- 96 to 954 +/- 103 mL/min; and (4) congestion index of the portal vein, from 15.1 +/- 8.3 to 15.6 +/- 8.8 cm, respectively (P = > 0.05). In addition, no significant changes in portal blood hemodynamics were noted after prolonged verapamil administration (P > 0.05). These results demonstrated that verapamil did not alter portal blood flow in patients with alcoholic liver cirrhosis.

[The significance of low levels of total proteins, albumins, globulins and complement factors in ascitic fluid and the development of spontaneous bacterial peritonitis in patients with liver cirrhosis]. / Znacenje snizene koncentracije ukupnih proteina, albumina, globulina i komponenti komplementa unutar asciticne tekucine u nastanku spontanog bakterijskog peritonitisa u bolesnika s cirozom jetre.

Spontaneous bacterial peritonitis is one of the most common complications of ascitic fluid in patients with liver cirrhosis. The aim of this study was to investigate the role of total protein, albumin, globulin and complement ascitic fluid concentrations in development of spontaneous bacterial peritonitis in patients with liver cirrhosis. In patients with liver cirrhosis and spontaneous bacterial peritonitis (n = 8) the ascitic fluid total protein, albumin and globulin concentrations were significantly lower than in patients with sterile ascites (n = 11) (p < 0.01). The ascitic fluid complement C3 and C4 concentrations were significantly lower in patients with spontaneous bacterial peritonitis than in patients with sterile ascites (9.1 +/- 3.1 mg/dL to 22.9 +/- 17.4 mg/dL, p < 0.01; 3.8 +/- 5.9 mg/dL to 8.2 +/- 5.9 mg/dL, p < 0.01, respectively). The ascites total protein, albumin, globulin and complement concentrations in cirrhotic patients with spontaneous bacterial peritonitis were significantly lower than in patients with sterile ascites demonstrating the importance of those factors in ascitic fluid defense against secondary bacterial infection.