DFT study of furfural conversion on a Re/Pt bimetallic surface: synergetic effect on the promotion of hydrodeoxygenation.

Density functional theory (DFT) calculations of furfural conversion were performed via hydrogenation and hydrodeoxygenation pathways on a bimetallic surface, namely, a thin oxygen-covered Re film on Pt(111). In the most stable adsorption conformation, the furyl ring component adsorbs on the Re edge site and the carbonyl oxygen also plays an important role in the adsorption strength. It was found that, while furfural conversion is kinetically favoured in the hydrogenation route to generate furfuryl alcohol, the hydrodeoxygenation mechanism to generate 2-methylfuran and water is thermodynamically favoured. Our results show that the hydrodeoxygenation product 2-methylfuran is achievable via the hydrogenation of furfural into hydroxyalkyl species, followed by C-OH bond cleavage, and successive hydrogenations of the furyl-CH intermediate. However, the production of 2-methylfuran is prohibited as the oxidised Re surface cannot accept further oxygen deposition, due to the oxygen-related species are difficult to remove in the form of water via hydrogenation. By comparing the results from the Re/Pt system to those on a monometallic flat Pt surface, we were able to demonstrate that incorporation of the oxophilic metals to active metals for hydrogenation could promote the hydrodeoxygenation route by reducing the barrier of C-O bond cleavage.

[A new challenge in clinical practice: resistance to directly acting antivirals in hepatitis C treatment].

Directly acting antivirals (DAAs) is a major treatment of hepatitis C virus (HCV) overseas. But DAAs resistance is getting more and more clinicians' attention. DAAs have not been approved in China to date, even though some of them are in clinical trials. However, a good knowledge of DAAs resistance is important on optimizing HCV treatment regimens, increasing sustained virological response (SVR) and decreasing treatment failure in clinical. In this review, DAAs resistance mechanism and virologic barrier to resistance, the prevalence of pre-existing DAAs resistance-associated variants (RAVs), the impact of RAVs on treatment outcome, the options of treatment regimens after resistance and drug resistance testing are discussed, hoping to provide some help for DAAs' standardized treatment in China in the future.

Systematic review with meta-analysis: combination treatment of regimens based on pegylated interferon for chronic hepatitis B focusing on hepatitis B surface antigen clearance.

BACKGROUND: The seroclearance of hepatitis B surface antigen (HBsAg) in patients with chronic hepatitis B (CHB) is considered to be associated with favourable clinical outcomes. AIMS: This meta-analysis was performed to establish the proportion of HBsAg loss rates among CHB patients who received combination treatment based on pegylated interferon (PegIFN). Four combination strategies have been studied with the aim of improving HBsAg loss: "de novo," "NA-experienced," "switch-to" and "add-on." This meta-analysis was performed to determine which, if any, of these combination strategies was more effective. METHODS: Medline, Web of Science and Embase databases were searched from inception to December 2017. The proportion of patients who achieved HBsAg loss after combination therapy was pooled using a random-effects model. RESULTS: Twenty-four studies fulfilled the meta-analysis criteria. The overall pooled proportion suggested that the rate of HBsAg loss could be increased to 9% (95% CI: 7%-12%) based on the combination treatment in CHB patients. Compared with "de novo" strategy (8%, 95% CI: 6%-10%), the "nucleos(t)ide analogues-experienced" (11%, 95% CI: 8%-15%) was found to be more likely (P = 0.036) to achieve a response. Compared with the "add-on" strategy (8%, 95% CI: 5%-13%), the "switch-to" (14%, 95% CI: 9%-20%) was found to be more likely (P = 0.012) to achieve HBsAg loss. CONCLUSION: The "nucleos(t)ide analogues-experienced" strategy was more effective than the "De novo" strategy in achieving HBsAg loss for CHB patients. Combination treatment using regimens based on Peg-IFN may be useful to help nucleos(t)ide analogues-treated patients, who have experienced at least 48 weeks of nucleot(s)ide analogue, achieve HBsAg seroclearance.

A new quadruple therapy for Helicobacter pylori using tripotassium dicitrato bismuthate, furazolidone, josamycin and famotidine.

BACKGROUND: In our previous study, a triple therapy using tripotassium dicitrato bismuthate (TDB), josamycin and furazolidone achieved a suboptimal cure rate of Helicobacter pylori infection. AIM: To investigate whether the addition of an antisecretory agent raises the cure rate using this regimen. METHODS: One hundred and twenty H. pylori positive patients with peptic ulcer disease or functional dyspepsia were randomly assigned to receive 1-week quadruple therapy of TDB 240 mg b.d., furazolidone 100 mg b.d., josamycin 1000 mg b.d. and famotidine 20 mg b.d. (BFJF group), or triple therapy of TDB 240 mg b.d., furazolidone 100 mg b.d. and clarithromycin 250 mg b.d. (BFC group). H. pylori status was assessed by histology and culture of gastric biopsy specimens before and at least 4 weeks after completion of therapy. RESULTS: Seven patients (three in the BFJF group and four in the BFC group) dropped out. Eradication rates (intention-to-treat/per protocol) were 90%/95% in the BFJF group and 82%/88% in the BFC group, respectively (P > 0.05). Duodenal ulcer healing rates were 94% (16/17) in the BFJF group and 80% (20/25) in the BFC group, respectively (P > 0.05). Mild side-effects occurred in 11 (18%) patients in the BFJF group and 10 (17%) in the BFC group (P > 0.05). CONCLUSIONS: One-week quadruple therapy consisting of TDB, furazolidone, josamycin and famotidine achieves a high cure rate of H. pylori infection.

Five-year experience of critical incidents associated with patient-controlled analgesia in an Irish University Hospital.

BACKGROUND: Patient-controlled analgesia (PCA) is a common and effective means of managing post-operative pain. We sought to identify factors that may lead to critical incidents (CIs) in patient safety when using PCA in our institution. METHODS: An observational study of prospectively collected data of patients who received PCA from 2002 to 2006 was performed. All CIs were documented and analysed by staff members of the acute pain service (APS). Cause analysis of CIs was undertaken to determine if measures can be instituted to prevent recurrence of similar events. RESULTS: Over eight thousand patients (8,240) received PCA. Twenty-seven CIs were identified. Eighteen were due to programming errors. Other CIs included co-administration of opioids and oversedation. CONCLUSION: In our institution, the largest contributory factor to CIs with PCAs was programming error. Strategies to minimize this problem include better education and surveillance.

An insight into alkali promotion: a density functional theory study of CO dissociation on K/Rh(111).

The important role of alkali additives in heterogeneous catalysis is, to a large extent, related to the high promotion effect they have on many fundamental reactions. The wide application of alkali additives in industry does not, however, reflect a thorough understanding of the mechanism of their promotional abilities. To investigate the physical origin of the alkali promotion effect, we have studied CO dissociation on clean Rh(111) and K-covered Rh(111) surfaces using density functional theory. By varying the position of potassium atoms relative to a dissociating CO, we have mapped out the importance of different K effects on the CO dissociation reactions. The K-induced changes in the reaction pathways and reaction barriers have been determined; in particular, a large reduction of the CO dissociation barrier has been identified. A thorough analysis of this promotion effect allows us to rationalize both the electronic and the geometrical factors that govern alkali promotion effect: (i) The extent of barrier reductions depends strongly on how close K is to the dissociating CO. (ii) Direct K-O bonding that is in a very short range plays a crucial role in reducing the barrier. (iii) K can have a rather long-range effect on the TS structure, which could reduce slightly the barriers.