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Solar fuel production, water splitting, and CO2 reduction by sunlight‐assisted catalytic reactions, are attractive and environmentally sustainable approaches used to generate energy. Since many different parameters, including energy band structures, electronic conductivity, surface area, porosity, catalytic activity, and stability of photocatalytic materials, determine the photocatalytic reaction, a single photocatalytic material is often insufficient to fulfill all the requirements. Hybridization to complement the limitations of two or more component materials can provide a viable solution. Particularly, hybridization with metal organic frameworks (MOFs), a new class of materials with excellent controllability of topology, surface area, porosity, morphology, band structure, electrical conductivity, and composition, enables the on‐demand design of a myriad of high‐performance photocatalysts. Moreover, hybrids formed by MOF‐derived materials inherit the distinctive merits from the MOF and offer further diversification for hybrid photocatalysts. Here, the rational design of MOF‐based hybrid photocatalysts for solar fuel production is discussed. The synthetic strategies of diverse MOF‐based hybrids, the key physicochemical parameters of hybrids to determine photocatalytic and photoelectrochemical reactions, and the mechanisms underlying the synergistic enhancement of solar fuel production are reviewed. Moreover, remaining challenges and future perspectives are addressed. [ABSTRACT FROM AUTHOR]

Volatile aromatic compounds are major air pollutants, and their health impacts should be assessed accurately based on the concentration and composition of gas mixtures. Herein, novel bilayer sensors consisting of a SnO2 sensing layer and three different xRh‐TiO2 catalytic overlayers (x = 0.5, 1, and 2 wt%) are designed for the new functionalities such as the selective detection, discrimination, and analysis of benzene, toluene, and p‐xylene. The 2Rh‐TiO2/SnO2 bilayer sensor shows a high selectivity and response toward ppm‐ and sub‐ppm‐levels of benzene over a wide range of sensing temperatures (325–425 °C). An array of 0.5Rh‐, 1Rh‐, and 2Rh‐TiO2/SnO2 sensors exhibits discrimination and composition analyses of aromatic compounds. The conversion of gases into more active species at moderate catalytic activation and the complete oxidation of gases into non‐reactive forms by excessive catalytic promotion are proposed as the reasons behind the enhancement and suppression of analyte gases, respectively. Analysis using proton transfer reaction‐quadrupole mass spectrometer (PTR‐QMS) is performed to verify the above proposals. Although the sensing characteristics exhibit mild moisture interference, bilayer sensors with systematic and tailored control of gas selectivity and response provide new pathways for monitoring aromatic air pollutants and evaluating their health impacts. [ABSTRACT FROM AUTHOR]

Water poisoning, the dependence of gas‐sensing characteristics on moisture, in oxide chemiresistors remains a long‐standing challenge. Various approaches are explored to mitigate water poisoning but they are often accompanied by significant deterioration of sensing capabilities such as gas response deterioration, gas selectivity alteration, and sensor resistance increase up to unmeasurable levels. Herein, a novel sensor design with a moisture‐blocking Tb4O7 overlayer is suggested as a facile and universal strategy to remove moisture poisoning without sacrificing intrinsic sensing properties. A submicrometer‐thick coating of Tb4O7 overlayer on In2O3 sensors effectively eliminates the humidity dependence of the gas‐sensing characteristics without significantly altering the gas response, selectivity, and sensor resistance. Furthermore, the general validity of the water‐blocking effect using the Tb4O7 overlayer is confirmed in diverse gas sensors using SnO2, ZnO, and Pd/SnO2. The negligible moisture interference of the bilayer sensor is explained in terms of the hydrophobic nature of the Tb4O7 overlayer and the prevention of formation of the OH radical by the interaction between Tb4O7 and In2O3. A universal solution to design diverse humidity‐independent gas sensors with different gas selectivities can open up new pathways toward building accurate and robust gas sensors with new functionalities and high‐performance artificial olfaction. [ABSTRACT FROM AUTHOR]

A highly selective and sensitive detection of the plant hormone ethylene, particularly at low concentrations, is essential for controlling the growth, development, and senescence of plants, as well as for ripening of fruits. However, this remains challenging because of the non‐polarity and low reactivity of ethylene. Herein, a strategy for detecting ethylene at a sub‐ppm‐level is proposed by using oxide semiconductor chemiresistors with a nanoscale oxide catalytic overlayer. The SnO2 sensor coated with the nanoscale catalytic Cr2O3 overlayer exhibits rapid sensing kinetics, good stability, and an unprecedentedly high ethylene selectivity with exceptional gas response (Ra/Rg − 1, where Ra represents the resistance in air and Rg represents the resistance in gas) of 16.8 at an ethylene concentration of 2.5 ppm at 350 °C. The sensing mechanism underlying the ultraselective and highly sensitive ethylene detection in the unique bilayer sensor is systematically investigated with regard to the location, configuration, and thickness of the catalytic Cr2O3 overlayer. The mechanism involves the effective catalytic oxidation of interfering gases into less‐ or non‐reactive species, without limiting the analyte gas transport. The sensor exhibits a promising potential for achieving a precise quantitative assessment of the ripening of five different fruits. [ABSTRACT FROM AUTHOR]

Monolayers of periodic porous Co3O4 inverse opal (IO) thin films for gas-sensor applications were prepared by transferring cobalt-solution-dipped polystyrene (PS) monolayers onto sensor substrates and subsequent removal of the PS template by heat treatment. Monolayer Co3O4 IO thin films having periodic pores ( d≈500 nm) showed a high response of 112.9 to 5 ppm C2H5OH at 200 °C with low cross-responses to other interfering gases. Moreover, the selective detection of xylene and methyl benzenes (xylene+toluene) could be achieved simply by tuning the sensor temperature to 250 and 275 °C, respectively, so that multiple gases can be detected with a single chemiresistor. Unprecedentedly high ethanol response and temperature-modulated control of selectivity with respect to ethanol, xylene, and methyl benzenes were attributed to the highly chemiresistive IO nanoarchitecture and to the tuned catalytic promotion of different gas-sensing reactions, respectively. These well-ordered porous nanostructures could have potential in the field of high-performance gas sensors based on p-type oxide semiconductors. [ABSTRACT FROM AUTHOR]

Pure and palladium-loaded Co3O4 hollow hierarchical nanostructures consisting of nanosheets have been prepared by solvothermal self-assembly. The nanostructures exhibited an ultrahigh response and selectivity towards p-xylene and toluene. The responses (resistance ratio) of the palladium-loaded Co3O4 hollow hierarchical nanostructures to 5 ppm of p-xylene and toluene were as high as 361 and 305, respectively, whereas the selectivity values (response ratios) towards p-xylene and toluene over interference from ethanol were 18.1 and 16.1, respectively. We attributed the giant response and unprecedented high selectivity towards methylbenzenes to the abundant adsorption of oxygen by Co3O4, the high chemiresistive variation in the Co3O4 nanosheets (thickness≈11 nm), and the catalytic promotion of the specific gas-sensing reaction. The morphological design of the p-type Co3O4 nanostructures and loading of the palladium catalyst have paved a new way to monitoring the most representative indoor air pollutants in a highly selective, sensitive, and reliable manner. [ABSTRACT FROM AUTHOR]

Yolk-shell-structured Zn-Fe-S multicomponent sulfide materials with a 1:2 Zn/Fe molar ratio were prepared applying a sulfidation process to ZnFe2O4 yolk-shell powders. The Zn-Fe-S powders had mixed sphalerite (Zn,Fe)S and hexagonal FeS crystal structures. The discharge capacities of the Zn-Fe-S powders sulfidated at 350 °C at a constant current density of 500 mA g−1 for the first, second, and fiftieth cycles were 1098, 912, and 913 mA h g−1, respectively. The powders exhibited a high discharge capacity of 602 mA h g−1 even at the high current density of 10 A g−1. The synergistic effect of yolk-shell structure and multicomponent composition improved the electrochemical properties of Zn-Fe-S powders. [ABSTRACT FROM AUTHOR]

Tin oxide (SnO2) nanotubes with a fiber-in-tube structure have been prepared by electrospinning and the mechanism of their formation has been investigated. Tin oxide-carbon composite nanofibers with a filled structure were formed as an intermediate product, which were then transformed into SnO2 nanotubes with a fiber-in-tube structure during heat treatment at 500°C. Nanofibers with a diameter of 85 nm were found to be located inside hollow nanotubes with an outer diameter of 260 nm. The prepared SnO2 nanotubes had well-developed mesopores. The discharge capacities of the SnO2 nanotubes at the 2nd and 300th cycles at a current density of 1 Ag-1 were measured as 720 and 640 mAhg-1, respectively, and the corresponding capacity retention measured from the 2nd cycle was 88%. The discharge capacities of the SnO2 nanotubes at incrementally increased current densities of 0.5, 1.5, 3, and 5 Ag-1 were 774, 711, 652, and 591 mAhg-1, respectively. The SnO2 nanotubes with a fiber-in-tube structure showed superior cycling and rate performances compared to those of SnO2 nanopowder. The unique structure of the SnO2 nanotubes with a fiber@void@tube configuration improves their electrochemical properties by reducing the diffusion length of the lithium ions, and also imparts greater stability during electrochemical cycling. [ABSTRACT FROM AUTHOR]

High-temperature flame spray pyrolysis is employed for finding highly efficient nanomaterials for use in lithium-ion batteries. CoO x-FeO x nanopowders with various compositions are prepared by one-pot high-temperature flame spray pyrolysis. The Co and Fe components are uniformly distributed over the CoO x-FeO x composite powders, irrespective of the Co/Fe mole ratio. The Co-rich CoO x-FeO x composite powders with Co/Fe mole ratios of 3:1 and 2:1 have mixed crystal structures with CoFe2O4 and Co3O4 phases. However, Co-substituted magnetite composite powders prepared from spray solutions with Co and Fe components in mole ratios of 1:3, 1:2, and 1:1 have a single phase. Multicomponent CoO x-FeO x powders with a Co/Fe mole ratio of 2:1 and a mixed crystal structure with Co3O4 and CoFe2O4 phases show high initial capacities and good cycling performance. The stable reversible discharge capacities of the composite powders with a Co/Fe mole ratio of 2:1 decrease from 1165 to 820 mA h g−1 as the current density is increased from 500 to 5000 mA g−1; however, the discharge capacity again increases to 1310 mA h g−1 as the current density is restored to 500 mA g−1. [ABSTRACT FROM AUTHOR]

A continuous, single-step, and large-scale preparation of Pd-catalyst-loaded SnO2 yolk-shell spheres is demonstrated. These nanostructures show an unusually high response and selectivity to methyl benzenes, such as xylene and toluene, with very low cross-responses to various interfering gases, making them suitable for precise monitoring of indoor air quality. [ABSTRACT FROM AUTHOR]

Hierarchical SnO2 fibers assembled from wrinkled thin tubes are synthesized by controlling the microphase separation between tin precursors and polymers, by varying flow rates during electrospinning and a subsequent heat treatment. The inner and outer SnO2 tubes have a number of elongated open pores ranging from 10 nm to 500 nm in length along the fiber direction, enabling fast transport of gas molecules to the entire thin-walled sensing layers. These features admit exhaled gases such as acetone and toluene, which are markers used for the diagnosis of diabetes and lung cancer. The open tubular structures facilitated the uniform coating of catalytic Pt nanoparticles onto the inner SnO2 layers. Highly porous SnO2 fibers synthesized at a high flow rate show five-fold higher acetone responses than densely packed SnO2 fibers synthesized at a low flow rate. Interestingly, thin-wall assembled SnO2 fibers functionalized by Pt particles exhibit a dramatically shortened gas response time compared to that of un-doped SnO2 fibers, even at low acetone concentrations. Moreover, Pt-decorated SnO2 fibers significantly enhance toluene response. These results demonstrate the novel and practical feasibility of thin-wall assembled metal oxide based breath sensors for the accurate diagnosis of diabetes and potential detection of lung cancer. [ABSTRACT FROM AUTHOR]

There has been mounting evidence that dysregulation of apoptosis is involved in the mechanisms of cancer development and somatic mutations of apoptosis-related genes have been reported in human cancers. Noxa, a Bcl-2 homology 3 (BH3)-only member of the Bcl-2 family, is known to interact with anti-apoptotic Bcl-2 family members and induces apoptosis. The aim of this study was to explore the possibility that the Noxa gene is mutated in human cancers. We have analyzed the entire coding region and all splice sites of the Noxa gene for the detection of somatic mutations in a series of human cancers, including carcinomas from stomach, colon, liver, urinary bladder and lung by polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP), and DNA sequencing. We found one somatic mutation of the Noxa gene in a transitional cell carcinoma (TCC) of the urinary bladder. To evaluate the functional alterations of the mutant in apoptosis, we overexpressed the mutant and wild-type Noxa in 293T and HeLa cells, but could not find any significant difference in cell death between the wild-type and mutant Noxa. These data suggest that Noxa is rarely mutated in human carcinomas and that the contribution of Noxa gene mutation in the pathogenesis of human cancer might not be related to cell death mechanisms. [ABSTRACT FROM AUTHOR]

Elevated levels of the calcium-binding protein S100A4 cause metastasis of benign rat mammary tumor cells. To investigate whether S100A4 plays an important role in the invasion and metastasis of gastric cancers, we examined the gene mutations in the coding regions and expression patterns of the S100A4 in gastric adenocarcinoma in Korea. Moderate to strong expression of S100A4 was found in 53 (68.8%) of the 77 gastric adenocarcinomas, whilst normal gastric epithelium either failed to stain or showed weak staining. Interestingly, S100A4 expression was more frequently observed in gastric cancer patients with advanced gastric cancer (p=0.039), positive lymph node metastasis (p=0.001), and peritoneal dissemination (p=0.022). No gene mutations were found in the analyzed genomic area in 77 gastric adenocarcinomas and 15 gastric cancer cell lines. We found one single nucleotide polymorphism without an amino acid change, A99G, in two cases. These data suggest that the overexpression of S100A4 may be closely related to the aggressiveness of gastric cancer in Korea. [ABSTRACT FROM AUTHOR]

We analyzed the gene mutations and loss of heterozygosity (LOH) of the HCCS1 gene using intragenic polymorphic markers in a series of 88 primary HCCs. We found two sequence variations at exon 5 and 14 in both normal and tumor DNAs of case 50 and 51, respectively. The variation in case 50 led to a reading frameshift and a premature stop (TGA) at codon 125 and case 51 showed amino acid change at codon 448 (Val→Ala, GT G→GC G). Interestingly, these variations were not found in peripheral lymphocytes of 69 normal individuals and 227 cancer patients (86 HCC, 75 unselected gastric cancer, and 66 breast cancer), suggesting that these two variations are mutation, not polymorphism. In addition, we found 14 novel intragenic polymorphic sites in the HCCS1 gene. Thirty-two (47%) of sixty-eight informative cases showed allelic loss at at least one or more intragenic polymorphic sites, but there was no significant relationship between the frequency of LOH and clinicopathologic parameters. These results suggest that mutation of the HCCS1 gene might not be a main inactivation mechanism in the development of Korean HCC and that the HCCS1 gene might be involved in acceleration of the tumorigenic process in Korean HCC. [ABSTRACT FROM AUTHOR]

Among the systems triggering apoptosis, the Fas-Fas ligand (FasL) system is recognized as a major pathway for the induction of apoptosis in cells and tissues. Ligation of Fas by either an agonistic antibody or FasL transmits a ‘death signal’ to the target cell, potentially triggering apoptosis. Alterations of genes along the Fas-mediated apoptosis pathway have been reported in many human cancers. However, there have been no data regarding FasL gene mutations in human cancers. We hypothesized that FasL gene mutation might be involved in the development of non-Hodgkin lymphoma (NHL). In this study, we analyzed the entire coding region of the FasL gene for the detection of somatic mutations in a series of 111 NHLs and found that one tumor had a FasL gene mutation in the cytoplasmic domain. To evaluate the functional alterations of the mutant in apoptosis, we overexpressed the mutant in 293T cells, but couldn't find any significant loss of cell death compared to the wild-type FasL. Together, these data suggest that FasL is occasionally mutated in human NHL and that FasL mutations appear to play no role in the pathogenesis of the vast majority of NHLs. [ABSTRACT FROM AUTHOR]

CO 2 reduction, hydrogen generation, MOF-based hybrids, photocatalysts, solar fuel production Keywords: CO 2 reduction; hydrogen generation; MOF-based hybrids; photocatalysts; solar fuel production EN CO 2 reduction hydrogen generation MOF-based hybrids photocatalysts solar fuel production 1 1 1 07/27/21 20210722 NES 210722 In article number 2003052 Ho Won Jang, Jong-Heun Lee and co-workers review the recent advances in hybrid photocatalysts using metal-organic frameworks (MOFs) and MOF-derived nanostructures for solar fuel production and suggest the key physicochemical parameters to determine photocatalytic and photoelectrochemical reactions. Hybrid Photocatalysts: MOF-Based Hybrids for Solar Fuel Production (Adv. [Extracted from the article]

Bilayer Sensors: A General Solution to Mitigate Water Poisoning of Oxide Chemiresistors: Bilayer Sensors with Tb4O7 Overlayer (Adv. Funct. Keywords: bilayer sensors; gas sensors; oxide semiconductors; Tb 4O 7 water poisoning EN bilayer sensors gas sensors oxide semiconductors Tb 4O 7 water poisoning 1 1 1 02/05/21 20210203 NES 210203 In article number 2007895, Jong-Heun Lee and co-workers show that the coating of a moisture-blocking Tb SB 4 sb O SB 7 sb overlayer provides a general and facile solution to mitigate the water poisoning effect of oxide semiconductor gas sensors without significant alteration of the gas-sensing characteristics such as gas response, selectivity, and sensor resistance, enabling the design of reliable gas sensors and artificial olfaction with the strong endurance against the variation in the ambient moisture. Bilayer sensors, gas sensors, oxide semiconductors, Tb 4O 7 water poisoning. [Extracted from the article]

In the present work, we report the processing of ultrahard tungsten carbide (WC) nanocomposites with 6 wt% zirconia additions. The densification is conducted by the spark plasma sintering (SPS) technique in a vacuum. Fully dense materials are obtained after SPS at 1300°C for 5 min. The sinterability and mechanical properties of the WC-6 wt% ZrO2 materials are compared with the conventional WC-6 wt% Co materials. Because of the high heating rate, lower sintering temperature, and short holding time involved in SPS, extremely fine zirconia parlicles (∼100 nm) and submicrometer WC grains are retained in the WC-ZrO2 nanostructured composites. Independent of the processing route (SPS or pressureless sintering in a vacuum), superior hardness (21-24 GPa) is obtained with the newly developed WC-ZrO2 materials compared with that of the WC-Co materials (15-17 GPa). This extremely high hardness of the novel WC-ZrO2 composites is expected to lead to significantly higher abrasive-wear resistance. [ABSTRACT FROM AUTHOR]

Spark plasma sintering (SPS) method was used to obtain dense NASICON ceramics with a high-electrical conductivity, which was compared with conventional solid-state sintering. The fully dense NASICON was achieved at a relatively lowsintering temperature of 1100°C, whereas the apparent density of the specimen prepared by conventional sintering was 74% of the theoretical density. The highest conductivity of 1.8 × 10-3 Scm-1 at 25°C, which is comparable to the best value reported, was achieved using the SPS process. Considering the phase, density, and microstructure, it appears that there is more room for improved conductivity by controlling the amount of monoclinic zirconia and the resistive grainboundary glass phase. [ABSTRACT FROM AUTHOR]

Describes the powder preparation, powder characterization and sintering behavior of translucent magnesium aluminum spinel ceramics. Synthesis of the precursor via precipitation; Use of ammonium bicarbonate as the precipitant; Characterization of the precursor by differential thermal analysis/thermogravimetry, X-ray diffractometry and scanning electron microscopy.