Ultrathin Bismuth Nanosheets as a Highly Efficient CO2 Reduction Electrocatalyst.

Electrochemical reduction of CO2 to value-added products is an important and challenging reaction for sustainable energy study. Herein, bismuth nanosheets with thickness of around 10 nm were prepared through the electrochemical reduction of Bi3+ . Ultrathin Bi nanosheets with numerous low-coordination sites can efficiently reduce CO2 to formate in aqueous solution. Within the potential range of -0.9 to -1.2 V vs. reversible hydrogen electrode (RHE), the faradaic efficiency of formate is over 90 %, outperforming many Bi catalysts. At -0.7 V, the Bi nanosheets exhibit much higher current for formate generation than that of bulk Bi, attributed to a high surface area and also modified intrinsic electronic properties brought about by the ultrathin structure. DFT calculations demonstrate that Bi nanosheets have much higher density of states at the Fermi level compared to bulk Bi, favoring improved CO2 reduction on Bi nanosheets. At -1.0 V, Bi nanosheets exhibit high selectivity for formate and excellent stability during 5 h of electrolysis.

Helicobacter pylori therapy: a paradigm shift.

Helicobacter pylori (H. Pylori) is a leading cause of gastroduodenal disease, including gastric cancer. H. pylori eradication therapies and their efficacy are summarized. A number of current treatment regimens will reliably yield >90% or 95% cure rates with susceptible strains. None has proven to be superior. We show how to predict the efficacy of a regimen in any population provided one knows the prevalence of antibiotic resistance. As with other infectious diseases, therapy should always be susceptibility-based. Susceptibility testing should be demanded. We provide recommendations for empiric therapies when that is the only option and describe how to distinguish studies providing misinformation from those providing reliable and interpretable data. When treated as an infectious disease, high H. pylori cure rates are relatively simple to reliably achieve.

The Toronto Consensus for the Treatment of Helicobacter pylori Infection in Adults.

BACKGROUND & AIMS: Helicobacter pylori infection is increasingly difficult to treat. The purpose of these consensus statements is to provide a review of the literature and specific, updated recommendations for eradication therapy in adults. METHODS: A systematic literature search identified studies on H pylori treatment. The quality of evidence and strength of recommendations were rated according to the Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach. Statements were developed through an online platform, finalized, and voted on by an international working group of specialists chosen by the Canadian Association of Gastroenterology. RESULTS: Because of increasing failure of therapy, the consensus group strongly recommends that all H pylori eradication regimens now be given for 14 days. Recommended first-line strategies include concomitant nonbismuth quadruple therapy (proton pump inhibitor [PPI] + amoxicillin + metronidazole + clarithromycin [PAMC]) and traditional bismuth quadruple therapy (PPI + bismuth + metronidazole + tetracycline [PBMT]). PPI triple therapy (PPI + clarithromycin + either amoxicillin or metronidazole) is restricted to areas with known low clarithromycin resistance or high eradication success with these regimens. Recommended rescue therapies include PBMT and levofloxacin-containing therapy (PPI + amoxicillin + levofloxacin). Rifabutin regimens should be restricted to patients who have failed to respond to at least 3 prior options. CONCLUSIONS: Optimal treatment of H pylori infection requires careful attention to local antibiotic resistance and eradication patterns. The quadruple therapies PAMC or PBMT should play a more prominent role in eradication of H pylori infection, and all treatments should be given for 14 days.

(210)Bi - from interference to advantage in (210)Pb determination with liquid scintillation counter.

A novel method for determination of (210)Pb activity concentration using a liquid scintillation counter (LSC) in environmental samples is presented. After radiochemical separation of (210)Pb on Eichrom Sr Resin column, the decay product (210)Bi starts to in-grow and interfere with the (210)Pb during measurement with LSC. Instead of eliminating this interference, a novel method utilises (210)Bi in-growth to improve the detection efficiency and subsequently to lower the minimum detectable activity (MDA). This allows for substantial reduction of the MDA compared to conventional methods.

Optimization of Bi2O3, TiO2, and Sb2O3 doped ZnO-based low-voltage varistor ceramic to maximize nonlinear electrical properties.

In ZnO-based low voltage varistor, the two essential features of microstructure determining its nonlinear response are the formation Bi-enriched active grain boundaries as well as a controlled ZnO grain size by secondary spinel-type phases. Besides, the microstructure and phase composition are strongly affected by the dopant concentration during sintering process. In this study, the optimal dopant levels of Bi2O3, TiO2, and Sb2O3 to achieve maximized nonlinear electrical property (alpha) were quantified by the response surface methodology (RSM). RSM was also used to understand the significance and interaction of the factors affecting the response. Variables were determined as the molar ratio of Bi2O3, TiO2, and Sb2O3. The alpha was chosen as response in the study. The 5-level-3-factor central composite design, with 20 runs, was used to conduct the experiments by ball milling method. A quadratic model was established as a functional relationship between three independent variables and alpha. According to the results, the optimum values of Bi2O3, TiO2, and Sb2O3 were obtained 0.52, 0.50, and 0.30, respectively. Under optimal conditions the predicted alpha (9.47) was calculated using optimal coded values from the model and the theoretical value is in good agreement with the value (9.43) obtained by confirmation experiment.

Determination of bismuth in solid samples by hydride generation atomic fluorescence spectrometry with a dielectric barrier discharge atomizer.

An atmospheric pressure dielectric barrier discharge (DBD) atomizer was investigated for bismuth (Bi) determination with hydride generation (HG) atomic fluorescence spectrometry (AFS). The characteristics of the atomizer and the effects of experimental parameters, including observation height, discharge power, flow rate of discharge gas and AFS carrier gas were optimized. The linear range of present method for Bi determination is 0.5-300.0 microg L(-1) with a detection limit of 0.07 microg L(-1) (3 sigma). The method was validated by the analysis of reference materials (GBW08517 and GSB-14) and the results agreed well with the reference values. The established method was applied to the determination of Bi in ore, soil and ash samples.

Feasibility of internal standardization in the direct and simultaneous determination of As, Cu and Pb in sugar-cane spirits by graphite furnace atomic absorption spectrometry.

Bismuth and Sb were evaluated as internal standards (IS) to minimize matrix effects on the direct and simultaneous determination of As, Cu, and Pb in cachaça by graphite furnace atomic absorption spectrometry using W-coated platform plus Pd-Mg(NO(3))(2) as modifier. For 20microL injected sample, calibration within the 0.5-10microg L(-1) As, 100-1000microg L(-1) Cu and 0.5-30microg L(-1) Pb intervals were established using the ratios As absorbance to Sb absorbance, Cu absorbance to Bi absorbance and Pb absorbance to Bi absorbance versus analytes concentration, respectively. Typical linear correlations of 0.998, 0.999 and 0.999 were, respectively, obtained. The proposed method was applied for direct determination of As, Cu and Pb in 10 commercial cachaça samples and results were in agreement with those obtained by inductively coupled plasma mass spectrometry at 95% confidence level. The found characteristic masses were 30pg As, 274pg Cu and 39pg Pb. The useful lifetime of the graphite tube was around 760 firings. Recoveries of As, Cu and Pb added to cachaça samples varied, respectively, from 98% to 109%, 97% to 108% and 98% to 104% with internal standards and from 48% to 54%, 53% to 92% and 62% to 97% without internal standards. The limits of detection were 0.13microg L(-1) As, 22microg L(-1) Cu and 0.05microg L(-1) Pb. The relative standard deviations (n=12) for a spiked sample containing 20microg L(-1) As, Pb and 500microg L(-1) Cu were 1.6%, 1.0%, and 1.8% with IS and 4.3%, 5.2%, and 5.5% without IS.

An evaluation of the quality of root fillings in mandibular incisors and maxillary and mandibular canines using different methodologies.

OBJECTIVES: To evaluate the quality of root fillings in mandibular incisors and maxillary and mandibular canines using different methodologies of evaluation, namely radiographs, the fluid transport test and the percentage of gutta-percha (PGP), and to determine if a correlation occurs between the results of the different methodologies used. METHODS: One group of mandibular incisors with oval canals (n=20) and one group of maxillary and mandibular canines (n=20) were instrumented and obturated by cold lateral compaction using AH 26 as the sealer. The filled roots were bucco-lingually and mesio-distally radiographed. Using a scoring system, the quality of each root filling was radiographically evaluated, the higher the score the poorer the quality. Fluid transport along the root filling was then measured using a fluid transportation device. Each root was horizontally sectioned 4 and 6mm from the apex. Images of the cross-sections were taken, using a microscope and a digital camera. Images were scanned into a PC as TIFF images. Using a KS 100 Imaging system the canal area and the gutta-percha filled areas were measured. The percentage of gutta-percha filled areas was calculated. RESULTS: Considering the radiographic scores of the two different projections together the score was significantly higher for the mandibular incisors than for the canines (P=0.039). The radiographic score was significantly higher for the mesio-distal radiograph in comparison with the bucco-lingual radiograph (P=0.0001), for the canines as well as the incisors. Using only the bucco-lingual radiograph there was no significant difference between the mandibular incisors and the canines (P=0.992). The mandibular incisors displayed significantly more fluid transport than the canines (P=0.049). A significantly greater percentage of gutta-percha filled areas was found in the cross-sections of canines as compared to the cross-sections of mandibular incisors (P=0.000001). The correlation between the radiographic score of the mesio-distal radiograph and the PGP 4 and 6mm was significant (P=0.013). There was no significant correlation between the FT and the radiograph or the FT and the PGP. CONCLUSIONS: The quality of the root fillings in oval canal-mandibular incisors may be compromised.

Sealing ability of MTA, Super EBA, Vitremer and amalgam as root-end filling materials

Este estudo avaliou a capacidade de selamento do agregado trióxido mineral (MTA Angelus), de um cimento de óxido de zinco e eugenol reforçado (Super EBA), de um cimento de ionômero de vidro reforçado por resina (Vitremer) e de um amálgama sem zinco (GS-80) (controle). Os canais radiculares de oitenta molares inferiores humanos foram acessados, limpos, modelados e obturados. Os ápices foram seccionados, e as cavidades, preparadas. Os dentes foram divididos em 4 grupos de 40 cavidades, retrobturados com os materiais e imersos em azul de metileno por 72 h a 37ºC. As raízes foram então seccionadas transversalmente a cada milímetro e avaliadas sob aumento, observando-se a penetração de corante a cada corte. Os dados foram avaliados usando-se o teste de Kruskal-Wallis (5%), que mostrou diferenças entre todos os materiais (p < 0,001). A ordem crescente de infiltração marginal foi MTA < Vitremer < Super EBA < amálgama. Níveis mais altos de infiltração foram observados nos cortes de primeiro milímetro de amálgama, Vitremer e MTA, quando comparados com o terceiro milímetro (p < 0,05).

Heavy metal poisoning in glass worker characterised by severe.

The paper presents the clinical description of the masticatory organ and biochemical assessment of dental tissue in a patient employed in a glassworks for 20 years. During 12 years the patient has suffered baldness ("Alopecia areata") and atypical extensive and non-healing cutaneous lesions. Dental examination revealed changes typical of chronic poisoning by cadmium and bismuth compounds.

Comparison of sensitivities of cells to X-ray therapy, chemotherapy, and isotope therapy using a tumor spheroid model.

Numerous treatment modalities have been used in treating microscopic carcinoma confined to the peritoneal cavity. However, there is little information at the cellular level regarding which modality is most effective in eradicating small nests of tumor cells. In order to determine whether chemotherapy, X rays, or isotope therapy is most effective, we have compared in a three-dimensional spheroid model the survival of cells after treatment with cis-platinum, X ray, or the investigational high-energy isotope 212-bismuth (Bi-212). In this study, V-79 cells were grown to 100-microns diameter spheroids. In killing spheroids, high-energy isotopes were at least six times more effective than X rays at fractionated doses of up to 1300 cGy. High-energy isotopes appear also to be as efficient as cis-platinum. Regardless of exposure time to treatment, Bi-212 was more toxic to spheroids than the other treatment modalities. From this study we conclude that high-energy isotope therapy biologically is very effective in eradicating microscopic nests of cells.

A critique of therapeutic trials in Helicobacter pylori-positive functional dyspepsia.

BACKGROUND/AIMS: Approximately 50% of patients with functional dyspepsia have Helicobacter pylori infection; it remains controversial whether this infection causes chronic symptoms, but rigorously conducted therapeutic trials should establish whether H. pylori plays a role in functional dyspepsia. The aim here was to determine whether the trials published over the past 10 years were methodologically adequate to establish a role for this infection in functional dyspepsia. METHODS: A broad-based Medline search to identify all treatment trials published between 1984 and 1993 was performed. All functional dyspepsia trials were systematically analyzed for potential design strengths and weaknesses. RESULTS: Sixteen trials were included; 8 reported that anti-H. pylori therapy was efficacious and 8 failed to detect a statistically significant benefit. However, in all studies one or more serious methodological weakness was identified, including nonrandomized, non-placebo-controlled designs, lack of maintenance of blindness, application of inadequate outcome measures, failure to eradicate infection and follow up patients after therapy, and inadequate study power. CONCLUSIONS: There is a pressing need for well-designed trials in H. pylori-positive dyspepsia, and practical suggestions are provided based on a review of the published literature.

Bismuto compuesto y preparados

1.Bolivia que es el primer pais productor de bismuto del mundo debe convertirse en gran laboratorio abastecedor de productos y preparados bismuticos, 2.Los vehículos las bases bismuticas para preparados inyectables deberan tener absoluta pureza y no ser alterados por la esterilizacion y conservación, 3.Las suspensioones inyectables deben ser preparadas con cuidado siguiendo las reglas de la técnica respectiva para evitar abcesos bismuticos o reaccion inflamatoria local, 4.Los preparados galénicos son numerosos e insustituibles en la terapéutica corriente