Comparison of the Influence of Oxygen Groups Introduced by Graphene Oxide on the Activity of Carbon Felt in Vanadium and Anthraquinone Flow Batteries.

An increasing number of studies focus on organic flow batteries (OFBs) as possible substitutes for the vanadium flow battery (VFB), featuring anthraquinone derivatives, such as anthraquinone-2,7-disulfonic acid (2,7-AQDS). VFBs have been postulated as a promising energy storage technology. However, the fluctuating cost of vanadium minerals and risky supply chains have hampered their implementation, while OFBs could be prepared from renewable raw materials. A critical component of flow batteries is the electrode material, which can determine the power density and energy efficiency. Yet, and in contrast to VFBs, studies on electrodes tailored for OFBs are scarce. Hence, in this work, we propose the modification of commercial carbon felts with reduced graphene oxide (rGO) and poly(ethylene glycol) for the 2,7-AQDS redox couple and to preliminarily assess its effects on the efficiency of a 2,7-AQDS/ferrocyanide flow battery. Results are compared to those of a VFB to evaluate if the benefits of the modification are transferable to OFBs. The modification of carbon felts with surface oxygen groups introduced by the presence of rGO enhanced both its hydrophilicity and surface area, favoring the catalytic activity toward VFB and OFB reactions. The results are promising, given the improved behavior of the modified electrodes. Parallels are established between the electrodes of both FB technologies.

Coding and non-coding co-expression network analysis identifies key modules and driver genes associated with precursor lesions of gastric cancer.

BACKGROUND: Helicobacter pylori infection is the most important risk factor for gastric cancer (GC). Human gastric adenocarcinoma develops after long-term H. pylori infection via the Correa cascade. This carcinogenic pathway describes the progression from gastritis to atrophy, intestinal metaplasia (IM), dysplasia and GC. Patients with atrophy and intestinal metaplasia are considered to have precancerous lesions of GC (PLGC). H. pylori eradication and endoscopy surveillance are currently the only interventions for preventing GC. Better knowledge of the biology of human PLGC may help find stratification markers and contribute to better understanding of biological mechanisms. One way to achieve this is by using co-expression network analysis. Weighted gene co-expression network analysis (WGCNA) is often used to identify modules from co-expression networks and relate them to clinical traits. It also allows identification of driver genes that may be critical for PLGC. AIM: The purpose of this study was to identify co-expression modules and differential gene expression in dyspeptic patients at different stages of the Correa pathway. METHODS: We studied 96 gastric biopsies from 78 patients that were clinically classified as: non-active (n = 10) and chronic-active gastritis (n = 20), atrophy (n = 12), and IM (n = 36). Gene expression of coding RNAs was determined by microarrays and non-coding RNAs by RNA-seq. The WGCNA package was used for network construction, module detection, module preservation and hub and driver gene selection. RESULTS: WGCNA identified 20 modules for coding RNAs and 4 for each miRNA and small RNA class. Modules were associated with antrum and corpus gastric locations, chronic gastritis and IM. Notably, coding RNA modules correlated with the Correa cascade. One was associated with the presence of H. pylori. In three modules, the module eigengene (ME) gradually increased in the stages toward IM, while in three others the inverse relationship was found. One miRNA module was negatively correlated to IM and was used for a mRNA-miRNA integration analysis. WGCNA also uncovered driver genes. Driver genes show both high connectivity within a module and are significantly associated with clinical traits. Some of those genes have been previously involved in H. pylori carcinogenesis, but others are new. Lastly, using similar external transcriptomic data, we confirmed that the discovered mRNA modules were highly preserved. CONCLUSION: Our analysis captured co-expression modules that provide valuable information to understand the pathogenesis of the progression of PLGC.

Cross-sectional study of human coding- and non-coding RNAs in progressive stages of Helicobacter pylori infection.

Helicobacter pylori infects 4.4 billion individuals worldwide and is considered the most important etiologic agent for peptic ulcers and gastric cancer. Individual response to H. pylori infection is complex and depends on complex interactions between host and environmental factors. The pathway towards gastric cancer is a sequence of events known as Correa's model of gastric carcinogenesis, a stepwise inflammatory process from normal mucosa to chronic-active gastritis, atrophy, metaplasia and gastric adenocarcinoma. This study examines gastric clinical specimens representing different steps of the Correa pathway with the aim of identifying the expression profiles of coding- and non-coding RNAs that may have a role in Correa's model of gastric carcinogenesis. We screened for differentially expressed genes in gastric biopsies by employing RNAseq, microarrays and qRT-PCR. Here we provide a detailed description of the experiments, methods and results generated. The datasets may help other scientists and clinicians to find new clues to the pathogenesis of H. pylori and the mechanisms of progression of the infection to more severe gastric diseases. Data is available via ArrayExpress.

Expression profile of circulating microRNAs in the Correa pathway of progression to gastric cancer.

BACKGROUND: Helicobacter pylori infection causes long-term chronic active gastritis, a risk factor for the intestinal and diffuse forms of gastric cancer. Most gastric cancers develop in a stepwise progression from chronic active gastritis to precursor lesions of gastric cancer. The early detection of gastric cancer improves survival. Studies with recent evidence have proposed circulating-microRNAs as biomarkers of cancer. OBJECTIVE: The purpose of this study was to explore the circulating-microRNA profile from H. pylori infection to gastric adenocarcinoma. METHODS: One hundred and twenty-three patients were enrolled and assigned to the discovery or the validation sets. In the discovery phase, circulating-microRNAs were measured by dye-based quantitative polymerase chain reaction and a selection of circulating-microRNAs was validated by probe-based quantitative polymerase chain reaction. A quality control protocol was used. RESULTS: One hundred and sixty-seven circulating-microRNAs were detected. Precursor lesions of gastric cancer and gastric cancer patients showed the downregulation of eight and five circulating-microRNAs, respectively. We further validated the deregulation of miR-196a-5p in precursor lesions of gastric cancer and the deregulation of miR-134-5p, miR-144-3p and miR-451a in gastric cancer. However, circulating-microRNAs exhibited moderate diagnostic performance due to the overlap of circulating-microRNA expression between non-cancer and cancer patients. miR-144-3p/miR-451a expression levels were correlated. Interestingly, these microRNAs are in 17q11.2, a site of rearrangements associated with gastric cancer. CONCLUSION: Circulating-microRNAs are deregulated in precancerous and gastric cancer patients but efforts are needed to improve their diagnostic accuracy.

N-Doped Carbon Xerogels as Pt Support for the Electro-Reduction of Oxygen.

Durability and limited catalytic activity are key impediments to the commercialization of polymer electrolyte fuel cells. Carbon materials employed as catalyst support can be doped with different heteroatoms, like nitrogen, to improve both catalytic activity and durability. Carbon xerogels are nanoporous carbons that can be easily synthesized in order to obtain N-doped materials. In the present work, we introduced melamine as a carbon xerogel precursor together with resorcinol for an effective in-situ N doping (3-4 wt % N). Pt nanoparticles were supported on nitrogen-doped carbon xerogels and their activity for the oxygen reduction reaction (ORR) was evaluated in acid media along with their stability. Results provide new evidences of the type of N groups aiding the activity of Pt for the ORR and of a remarkable stability for N-doped carbon-supported Pt catalysts, providing appropriate physico-chemical features.

Occult H. pylori infection partially explains 'false-positive' results of (13)C-urea breath test.

BACKGROUND: In a previous study, UBiT-100 mg, (Otsuka, Spain), a commercial (13)C-urea breath test omitting citric acid pre-treatment, had a high rate of false-positive results; however, it is possible that UBiT detected low-density 'occult' infection missed by other routine reference tests. We aimed to validate previous results in a new cohort and to rule out the possibility that false-positive UBiT were due to an 'occult' infection missed by reference tests. METHODS: Dyspeptic patients (n = 272) were prospectively enrolled and UBiT was performed, according to the manufacturer's recommendations. Helicobacter pylori infection was determined by combining culture, histology and rapid urease test results. We calculated UBiT sensitivity, specificity, positive and negative predictive values (with 95% CI). In addition, we evaluated 'occult' H. pylori infection using two previously-validated polymerase chain reaction (PCR) methods for urease A (UreA) and 16 S sequences in gastric biopsies. We included 44 patients with a false-positive UBiT, and two control groups of 25 patients each, that were positive and negative for all H. pylori tests. RESULTS: UBiT showed a false-positive rate of 17%, with a specificity of 83%. All the positive controls and 12 of 44 patients (27%) with false-positive UBiT were positive for all two PCR tests; by contrast, none of our negative controls had two positive PCR tests. CONCLUSIONS: UBiT suffers from a high rate of false-positive results and sub-optimal specificity, and the protocol skipping citric acid pre-treatment should be revised; however, low-density 'occult' H. pylori infection that was undetectable by conventional tests accounted for around 25% of the 'false-positive' results.

Carbon Nanofibers as Advanced Pd Catalyst Supports for the Air Electrode of Alkaline Metal-Air Batteries.

Carbon nanofibers are investigated as a support for Pd catalysts. The electrochemical behavior of these catalysts for both the oxygen reduction and oxygen evolution reactions is investigated in a half-cell configuration in alkaline solution (6 M KOH) at room temperature. The catalysts are compared with an internal benchmark consisting of Pd supported on Vulcan. Stress tests are also performed to assess the stability of the catalysts under the highly corrosive conditions occurring at the positive electrode, especially during oxygen evolution (high potential). Pd catalysts supported on carbon nanofibers show promising stability characteristics for applications as bifunctional oxygen catalysts in metal-air batteries.

Highly dispersed encapsulated AuPd nanoparticles on ordered mesoporous carbons for the direct synthesis of H2O2 from molecular oxygen and hydrogen.

AuPd nanoparticles (<3 nm) have been encapsulated on the pores of a nanostructured CMK-3 carbon prepared by a nanocasting procedure. This material has been shown to be an excellent catalyst for the direct synthesis of hydrogen peroxide from molecular hydrogen and oxygen.

Insulating diamond particles as substrate for Pd electrocatalysts.

The suitability of insulating highly crystalline diamond particles as support for Pd based electrocatalysts is explored for the first time by evaluating the electrochemical stripping of CO and oxidation of formic acid in acid solutions.

On-site production of hydrogen from mineral waste oils by thermocatalytic decomposition: an Aragon case study.

On-site production of hydrogen and carbon nanofibers by thermocatalytic decomposition (TCD) of mineral oil waste (MWO) is analyzed. An experimental study carried out at lab scale to estimate the yields that can be expected from TCD of the MWO collected in the Aragon area is presented. Based on these results, mass and energy balance have been carried out to have a preliminary estimation on the products that could be obtained by processing the 10 000 tonnes/year of MWO that can be collected in the Aragon region. The process would consist of four steps: (1) drying, (2) vaporization, (3) primary decomposition, and (4) catalytic decomposition. After drying and vaporization, MWO is converted in step 3 into fuel grade carbon and a gas mixture that mainly contains hydrogen and methane. Methane is partially converted in step 4 into hydrogen and a carbon material that contains carbon nanofibers which could be used to manufacture utilities with high added value. The 10 000 tonnes/year of MWO would yield 705 t/y of H2, 4962 t/y of fuel grade carbon, and 1016 t/y of pure carbon. The mixture obtained (71% H2: 23% CH4) could be used as a hydrogen source to obtain pure hydrogen or hydrogen-natural gas mixtures to fuel a captive fleet of public urban vehicles powered by fuel cells or dedicated ICE, respectively.