Photocatalytic solar hydrogen production from water on a 100-m2 scale.

The unprecedented impact of human activity on Earth's climate and the ongoing increase in global energy demand have made the development of carbon-neutral energy sources ever more important. Hydrogen is an attractive and versatile energy carrier (and important and widely used chemical) obtainable from water through photocatalysis using sunlight, and through electrolysis driven by solar or wind energy1,2. The most efficient solar hydrogen production schemes, which couple solar cells to electrolysis systems, reach solar-to-hydrogen (STH) energy conversion efficiencies of 30% at a laboratory scale3. Photocatalytic water splitting reaches notably lower conversion efficiencies of only around 1%, but the system design is much simpler and cheaper and more amenable to scale-up1,2-provided the moist, stoichiometric hydrogen and oxygen product mixture can be handled safely in a field environment and the hydrogen recovered. Extending our earlier demonstration of a 1-m2 panel reactor system based on a modified, aluminium-doped strontium titanate particulate photocatalyst4, we here report safe operation of a 100-m2 array of panel reactors over several months with autonomous recovery of hydrogen from the moist gas product mixture using a commercial polyimide membrane5. The system, optimized for safety and durability, and remaining undamaged on intentional ignition of recovered hydrogen, reaches a maximum STH of 0.76%. While the hydrogen production is inefficient and energy negative overall, our findings demonstrate that safe, large-scale photocatalytic water splitting, and gas collection and separation are possible. To make the technology economically viable and practically useful, essential next steps are reactor and process optimization to substantially reduce costs and improve STH efficiency, photocatalyst stability and gas separation efficiency.

OSPAR: A Corpus for Extraction of Organic Synthesis Procedures with Argument Roles.

There is a pressing need for the automated extraction of chemical reaction information because of the rapid growth of scientific documents. The previously reported works in the literature for the procedure extraction either (a) did not consider the semantic relations between the action and argument or (b) defined a detailed schema for the extraction. The former method was insufficient for reproducing the reaction, while the latter methods were too specific to their own schema and did not consider the general semantic relation between the verb and argument. In addition, they did not provide an annotated text that aligned with the structured procedure. Along these lines, in this work, we propose a corpus named organic synthesis procedures with argument roles (OSPAR) that is annotated with rolesets to consider the semantic relation between the verb and argument. We also provide rolesets for chemical reactions, especially for organic synthesis, which represent the argument roles of actions in the corpus. More specifically, we annotated 112 organic synthesis procedures in journal articles from Organic Syntheses and defined 19 new rolesets in addition to 29 rolesets from an existing language resource (Proposition Bank). After that, we constructed a simple deep learning system trained on OSPAR and discussed the usefulness of the corpus by comparing it with chemical description language (XDL) generated by a natural language processing tool, namely, SynthReader. While our system's output required more detailed parsing, it covered comparable information against XDL. Moreover, we confirmed that the validation of the output action sequence was easy as it was aligned with the original text.

Oxysulfide photocatalyst for visible-light-driven overall water splitting.

Oxysulfide semiconductors have narrow bandgaps suitable for water splitting under visible-light irradiation, because the electronegative sulfide ions negatively shift the valence band edges of the corresponding oxides1,2. However, the instability of sulfide ions during the water oxidation is a critical obstacle to simultaneous evolution of hydrogen and oxygen3. Here, we demonstrate the activation and stabilization of Y2Ti2O5S2, with a bandgap of 1.9 eV, as a photocatalyst for overall water splitting. On loading of IrO2 and Rh/Cr2O3 as oxygen and hydrogen evolution co-catalysts, respectively, and fine-tuning of the reaction conditions, simultaneous production of stoichiometric amounts of hydrogen and oxygen was achieved on Y2Ti2O5S2 during a 20 h reaction. The discovery of the overall water splitting capabilities of Y2Ti2O5S2 extends the range of promising materials for solar hydrogen production.

Temporal Variation of Radionuclide Contamination of Marine Plants on the Fukushima Coast after the East Japan Nuclear Disaster.

As a result of the Great East Japan Earthquake and associated tsunami in March 2011, the Fukushima Daiichi Nuclear Power Plant (FDNPP) released a large amount of radioactive material into the environment, resulting in contamination of many marine organisms. In this study, 15 marine algal species and a seagrass species were collected from the sublittoral zone of the Iwaki Coast of Fukushima Prefecture from May 2012 to June 2015 and analyzed for variations in 110mAg, 134Cs, and 137Cs over time. The results indicated that (1) 110mAg, 134Cs, and 137Cs were present in all marine plants collected in May 2012, (2) the concentration of 110mAg in the seagrass Phyllospadix iwatensis decreased significantly over time while the ecological half-life of 110mAg in P. iwatensis was longer at locations closer to the FDNPP, and (3) the 110mAg/137Cs radioactivity ratio of P. iwatensis was remarkably high until 2015, indicating that detectable 110mAg was present in the coastal environment 4 years after the accident. The concentration of 110mAg in P. iwatensis was higher than those in other marine algae, demonstrating a species-specific mechanism of accumulation.

Reactivity of a Tetra(o-tolyl)diborane(4) Dianion as a Diarylboryl Anion Equivalent.

Lithium and magnesium salts of tetra(o-tolyl)diborane(4) dianion, having B=B double bond character, were synthesized. It was clarified that the lithium salt of the dianion has a high-lying HOMO and a narrow HOMO-LUMO gap, which were perturbed by dissociation of Li+ cation, as judged by UV/Vis spectroscopy and DFT calculations. The lithium salt of the dianion reacted as two equivalents of a diarylboryl anion with CH2 Cl2 or S8 to give boryl-substituted products.

Reactivity of Highly Lewis-Acidic Diborane(4) toward C≡N and N=N Bonds: Uncatalyzed Addition and N=N Bond-Cleavage Reactions.

The diboration of the C≡N bond in organic nitriles, and the N=N bond in azobenzene and pyridazine, by the highly Lewis-acidic tetra(o-tolyl)diborane(4) are reported. In the reactions with nitriles, azobenzene, and pyridazine, the addition of diborane(4) to the C≡N and N=N bonds was observed. Conversely, the N=N bond in phthalazine was cleaved by an addition/rearomatization sequence.

Highly Efficient Water Oxidation Photoanode Made of Surface Modified LaTiO2 N Particles.

An improved variation of highly active/durable O2 -evolving LaTiO2 N powder-based photoelectrode has been fabricated by pre-cleaning the powder with mild polysulfonic acid and by homogeneous deposition of CoOx co-catalyst aided by microwave annealing. The treatment in aqueous solution of poly(4-styrene sulfonic acid) results in removal of surface LaTiO2 N layers, forming fine pores in the crystallites. The CoOx co-catalyst by microwave deposition in Co(NH3 )6 Cl3 /ethylene glycol homogeneously covers the particle surface. The LaTiO2 N powder is fabricated into particle-transferred electrodes on Ti thin film supported on solid substrate. The modified LaTiO2 N grains on the electrode serve as a highly active O2 -evolving photoanode achieving 8.9 mA cm-2 of the photocurrent density at 1.23 V versus reversible hydrogen electrode (RHE) in 0.1 m NaOH (pH 13) under solar-simulator irradiation Airmass 1.5 Global (AM 1.5G). The activity has been much improved, compared with conventional LaTiO2 N treated in mineral acid or with CoOx deposited by impregnation. The new electrode also exhibits better durability in fixed-potential chronoamperometric tests under AM 1.5G irradiation.

Tetraborylation of p-Benzynes Generated by the Masamune-Bergman Cyclization through Reaction Design Based on the Reaction Path Network.

Designing the reactant molecule of an initial reaction, based on quantum chemical pathway exploration, enabled us to access a new reaction, i.e., the tetraborylation reaction of p-benzynes generated from 1,2-diethynylbenzene derivatives, using bis(pinacolato)diborane(4) (B2pin2). Based on the reaction path network generated via the artificial-force-induced reaction (AFIR) method, desired and undesired paths were identified and used to modify the chemical structure of the reactant. After the in silico screening, the optimal structure of the reactant was determined to be a 1,2-diethynylbenzene derivative with a butylene linker. The reaction of the optimized reactant and its derivatives with an excess of B2pin2 gave the tetraborylated products in good yields (up to 58%). It is quite intriguing that the two carbons of p-benzyne behave formally as dicarbenes in this reaction.

Synthesis, optical and electrochemical properties of 4,4'-bibenzo[c]thiophene derivatives.

We designed and synthesized unsubstituted 4,4'-bibenzo[c]thiophene 4,4'-BBT and its silyl-substituted derivatives 1,1'-Si-4,4'-BBT and 1,1',3,3'-Si-4,4'-BBT with one or two tert-butyldimethylsilyl groups on each thiophene ring, as new π-building blocks in emitters, photosensitizers and semiconductors for organic optoelectronic devices. The characterization of 4,4'-BBT, 1,1'-Si-4,4'-BBT and 1,1',3,3'-Si-4,4'-BBT was successfully determined by FTIR, 1H and 13C NMR measurements, high-resolution mass spectrometry (HRMS) analysis, photoabsorption and fluorescence spectroscopy, cyclic voltammetry (CV) and density functional theory (DFT) calculations. Moreover, a single-crystal X-ray structural analysis was successfully made for 1,1'-Si-4,4'-BBT and 1,1',3,3'-Si-4,4'-BBT. The photoabsorption and fluorescence maxima (λ abs max and λ fl max) of the three 4,4'-bibenzo[c]thiophene derivatives in toluene exhibit bathochromic shifts in the order of 4,4'-BBT (359 nm and 410 nm) < 1,1'-Si-4,4'-BBT (366 nm and 420 nm) < 1,1',3,3'-Si-4,4'-BBT (371 nm and 451 nm). The HOMO and LUMO energy levels rise in the order of 4,4'-BBT (-5.55 eV and -2.39 eV) < 1,1'-Si-4,4'-BBT (-5.45 eV and -2.34 eV) < 1,1',3,3'-Si-4,4'-BBT (-5.34 eV and -2.30 eV), but the rise of the HOMO energy level is larger than that of the LUMO energy level, resulting in the bathochromic shift of the photoabsorption band from 4,4'-BBT to 1,1',3,3'-Si-4,4'-BBT. The fluorescence quantum yields (Φ fl) of 4,4'-BBT, 1,1'-Si-4,4'-BBT and 1,1',3,3'-Si-4,4'-BBT in toluene are 0.41, 0.41 and 0.36, respectively. It is worth mentioning that in the solid state 1,1'-Si-4,4'-BBT and 1,1',3,3'-Si-4,4'-BBT show relatively high Φ fl-solid values of 0.22 and 0.25, respectively, whereas 4,4'-BBT exhibits poor solid-state fluorescence properties (Φ fl-solid < 0.02). This work provides an efficient synthetic method for the 4,4'-bibenzo[c]thiophene derivatives and their photophysical properties in the solution and solid state, electrochemical properties and X-ray crystal structures.

Boosting photocatalytic overall water splitting by Co doping into Mn3O4 nanoparticles as oxygen evolution cocatalysts.

The effect of cobalt doping into a manganese oxide (tetragonal spinel Mn3O4) nanoparticle cocatalyst up to Co/(Co + Mn) = 0.4 (mol/mol) on the activity of photocatalytic water oxidation was studied. Monodisperse ∼10 nm CoyMn1-yO (0 ≤y≤ 0.4) nanoparticles were uniformly loaded onto photocatalysts and converted to CoxMn3-xO4 nanoparticles through calcination. 40 mol% cobalt-doped Mn3O4 nanoparticle-loaded Rh@Cr2O3/SrTiO3 photocatalyst exhibited 1.8 times-higher overall water splitting activity than that with pure Mn3O4 nanoparticles. Investigation on the band structure and electrocatalytic water oxidation activity of CoxMn3-xO4 nanoparticles revealed that the Co doping mainly contributes to the improvement of water oxidation kinetics on the surface of the cocatalyst nanoparticles.

Phase-segregated NiP x @FeP y O z core@shell nanoparticles: ready-to-use nanocatalysts for electro- and photo-catalytic water oxidation through in situ activation by structural transformation and spontaneous ligand removal.

The high overpotential of the oxygen evolution reaction is a critical issue to be overcome to realize efficient overall water splitting and enable hydrogen generation powered by sunlight. Homogeneous and stable nanoparticles (NPs) dispersed in solvents are useful as both electrocatalysts and cocatalysts of photocatalysts for the electro- and photo-catalytic oxygen evolution reaction, respectively, through their adsorption on various electrode substrates. Here, phase-segregated NiP x @FeP y O z core@shell NPs are selectively synthesized by the reaction of Fe(CO)5 with amorphous NiP x seed-NPs. The NiP x @FeP y O z NPs on conductive substrates exhibit higher electrocatalytic activity in the oxygen evolution reaction than those of other metal phosphide-based catalysts. The NiP x @FeP y O z NPs can also be used as a cocatalyst of an anodic BiVO4 photocatalyst to boost the photocatalytic water oxidation reaction. The excellent catalytic activity and high stability of the NiP x @FeP y O z NPs without any post-treatments are derived from in situ activation through both the structural transformation of NiP x @FeP y O z into mixed hydroxide species, (Ni, Fe)O x H y , and the spontaneous removal of the insulating organic ligands from NPs to form a smooth and robust (Ni, Fe)O x H y /substrate heterointerface during the oxygen evolution reaction.

A highly sensitive method for the detection of p16 methylation in the serum of colorectal cancer patients.

BACKGROUND: For the purpose of early detection of carcinomas, detection of p16 hypermethylation by methylation-specific polymerase chain reaction (MSP) in the serum of many kinds of malignancies has been introduced. An attempt to increase the sensitivity of this assay is reported for colorectal cancer. MATERIALS AND METHODS: DNA samples were subjected to limiting dilution before being divided into ten smaller samples. Subsequently, hemi-nested MSP was performed on those ten samples. The limiting dilution-MSP (LD-MSP) provided a 10-fold increase in sensitivity of the detection of methylated DNA compared with conventional MSP. RESULTS: Of 44 colorectal cancer patients, 30 (68%) exhibited abnormal promoter methylation of p16 in their serum DNA by LD-MSP, while 13 (30%) exhibited it by conventional MSP. As a control, the serum DNA of 50 patients with colorectal carcinomas whose corresponding tumor DNA had no methylation in the p16 promoter was screened for aberrant methylation. No methylation was found in the serum DNA of this control group by LD-MSP or conventional MSP. CONCLUSION: The high sensitivity of LD-MSP makes it possible to detect smaller amounts of tumor DNA in the serum than conventional MSP. This technique also has great specificity and no abnormal methylation in serum has yet been observed if the corresponding tumor does not exhibit methylation. This observation supports the idea that LD-MSP could be applied in clinical use for the detection of tumor DNA in serum.

TAOS1, a novel marker for advanced esophageal squamous cell carcinoma.

BACKGROUND: TAOS1 (tumor amplified and overexpressed sequence 1) was recently cloned and found to be possibly important in driving the amplification of 11q13 in oral squamous cell carcinoma (SCC). MATERIALS AND METHODS: Quantitative RT-PCR was performed to determine the possible relationship between TAOS1 gene expression levels and clinicopathological features in esophageal SCC. RESULTS: TAOS1 overexpression was observed in 7 out of 38 (18%) esophageal SCCs and CCND1 overexpression was observed in 4 out of 38 (11%), suggesting that TAOS1 was more frequently overexpressed than CCND1 in esophageal SCC. The examination of the correlation of TAOS1 overexpression with the clinicopathological features revealed a significant difference in lymph node metastasis (p = 0.014) and a trend towards advanced TNM stages (p = 0.074). CONCLUSION: The present results suggest that TAOS1 might serve as a new marker for predicting the malignancy of esophageal SCC.

Laparoscopy-assisted total gastrectomy for a case of MALT lymphoma: a case report.

A case of laparoscopy-assisted total gastrectomy with regional lymph node dissection for MALT (mucosa-associated lymphoid tissue) lymphoma is reported. The patient was a 45-year-old male with MALT lymphoma. Eradication of Helicobacter pylori as the initial therapy had failed to halt progression of the tumor. Considering certainty of the second therapy, he was transferred to surgical treatment. Total gastrectomy was required and this was performed by the laparoscopy-assisted approach. The postoperative course was satisfactory and the patient has been disease-free for 5 years after the operation. Laparoscopic operation could be a useful option in the second-line treatment for MALT lymphoma after failure to eradicate H. pylori.

Visible Light-Driven Z-Scheme Water Splitting Using Oxysulfide H2 Evolution Photocatalysts.

A Sm2Ti2S2O5 (STSO) oxysulfide photocatalyst prepared by a novel flux method showed a higher degree of crystallinity and greater photocatalytic activity than that prepared by conventional polymerized complex and sulfurization processes. Co-loading with both IrO2, as an oxidative cocatalyst, and Pt, as a reductive cocatalyst, was found to be essential for promoting the photocatalytic activity of the STSO. Visible light-driven Z-scheme water splitting into H2 and O2 was realized by utilizing the STSO photocatalyst for H2 evolution in conjunction with a WO3 photocatalyst treated with H+ and Cs+ and loaded with PtOx for O2 evolution, and a triiodide/iodide (I3-/I-) redox couple as a shuttle electron mediator. Various other narrow band gap oxysulfide photocatalysts with H2 evolution activity, such as La5Ti2CuS5O7 and La6Ti2S8O5, were also shown to be applicable as H2 evolution photocatalysts in the present Z-scheme water splitting system.

Expression level of thymidylate synthase is a good predictor of chemosensitivity to 5-fluorouracil in colorectal cancer.

BACKGROUND: It is important to seek the appropriate chemotherapy drugs to effectively eliminate colorectal cancers. To avoid unnecessary medication and uncomfortable side effects, it is important to estimate the chemosensitivity of cancers to 5-fluorouracil (5-FU) before chemotherapy. METHODS: We examined thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) gene expressions in 23 colorectal cancers, using quantitative reverse transcription-polymerase chain reaction (RT-PCR). We then evaluated the relationship between TS and DPD gene expression levels and the sensitivity of colorectal cancers to 5-FU, as determined by histoculture drug response assay (HDRA). RESULTS: A significant increase in the TS expression score was observed in 5-FU-sensitive colorectal cancers (0.57 +/- 0.19) compared to 5-FU-resistant ones (1.16 +/- 0.98; P = 0.029), whereas no significant differences in DPD expression scores were observed in 5-FU-sensitive colorectal cancers (0.86 +/- 1.19) compared to 5-FU-resistant ones (0.56 +/- 1.05; P = 0.603). CONCLUSIONS: TS mRNA may be useful as a predictor of the 5-FU chemosensitivity of colorectal cancers.

S100A2 overexpression is frequently observed in esophageal squamous cell carcinoma.

BACKGROUND: We previously detected that deltaNp63, a human p53 homologue, is an oncogene amplified in squamous cell carcinomas (SCC) including esophageal SCC. Subsequently, we examined global patterns of gene expression in cancer cells following deltaNp63 gene introduction using an oligonucleotide microarray approach. We identified S100A2, a Ca2+-binding protein, as a novel downstream mediator of deltaNp63. MATERIALS AND METHODS: In this study, we examined S100A2 expression in esophageal SCC cell lines and primary SCCs using Northern analysis. RESULTS: We found that 2 out of 8 (25%) cell lines and 14 out of 30 primary esophageal cancers (47%) showed S100A2 gene overexpression compared to paired normal tissues. To examine a possible relationship between S100A2 overexpression and clinicopathological features, we proceeded with statistical analysis. S100A2 overexpression was significantly-associated with higher age in esophageal SCC (p=0.0434). Interestingly, S100A2-overexpressing cancers showed a trend toward preferentially developing lymph node metastases and distant metastases (p=0.111 and 0.178, respectively). CONCLUSION: These results suggested that S100A2 might be related to the progression of esophageal SCC.

A cancer-prone case with a background of methylation of p16 tumor suppressor gene.

PURPOSE AND EXPERIMENTAL DESIGN: To date, the presence of p16 gene promoter methylation associated with loss of protein expression has been demonstrated frequently in digestive tract cancers. In this study, we tested for the methylation status of p16 promoter in normal tissue specimens using the methylation-specific PCR technique to examine whether p16 methylation already existed in the background of tumors. RESULTS: Aberrant promoter methylation of p16 gene was detected in 1 of 40 esophageal and 1 of 69 gastric and no colorectal epithelium specimens, and these 2 specimens were derived from the same patient. We also found the same methylation change in both tumor and blood cell DNA. CONCLUSION: These results suggested that the p16 gene was inactivated by methylation in normal background cells of this patient and that other additional factors may promote tumor development in his esophageal and gastric tissues.

Plasminogen activator inhibitor-1 as a potential marker for the malignancy of esophageal squamous cell carcinoma.

PURPOSE AND EXPERIMENTAL DESIGN: To test whether plasminogen activator inhibitor-1 (PAI-1) can serve as a candidate marker for the malignancy of esophageal squamous cell carcinoma (SCC), we performed a quantitative reverse transcription-PCR for PAI-1 gene and evaluated the possible relationship between PAI-1 gene expression levels and clinicopathological findings in esophageal SCC. RESULTS: Significant increases in PAI-1 scores were observed in metastasis-positive esophageal SCCs (3.08 +/- 0.80) compared with metastasis-negative ones (-0.31 +/- 0.62; P = 0.0042). PAI-1 expression scores significantly increased with tumor stage (P = 0.05, ANOVA). CONCLUSIONS: These results suggested that PAI-1 might serve as a new parameter for prediction of prognosis in esophageal SCC.

Molecular detection of circulating esophageal squamous cell cancer cells in the peripheral blood.

PURPOSE AND EXPERIMENTAL DESIGN: To detect surgically resectable tumors earlier and improve the prognosis of esophageal squamous cell carcinoma patients, we examined deltaNp63 expression that was specific for squamous cell carcinoma in blood samples obtained from 43 esophageal cancer patients. RESULTS: Seventeen of 33 (52%) patients with primary esophageal squamous cell carcinoma and 6 of 10 (60%) patients with postoperative recurrent squamous cell carcinoma had detectable deltaNp63 expression in their peripheral blood using deltaNp63-specific reverse transcription-PCR. Furthermore, deltaNp63 is a more sensitive marker compared with other commonly used tumor markers such as squamous cell carcinoma-associated antigen and carcinoembryonic antigen. CONCLUSIONS: This approach would be potentially useful for the monitoring of patients with this aggressive disease.