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Calcium hexaluminate (CA6) was incorporated into the matrix of magnesio aluminate spinel-alumina (MA-A) via infiltration of a porous preform fabricated from α-Al2O3 and MgO powders with a saturated calcium acetate solution and subsequent firing, forming CA6/(MA-A) functionally composites with graded fracture toughness. Actually, the porous preform was partially and perpendicularly immersed (1/4 of its length) in the solution. Owing to the capillary action, the calcium acetate solution was absorbed into the porous preform, and the different absorption distance led to the graded solution concentration in the height direction of the porous preform. The in-situ formation of CA6 conferred graded microstructures, as well as improved mechanical properties on the resultant composites. The CA6 content decreased gradually along the solution absorption direction, i.e., from one end [CA6/(MA-A) region] immersed in solution to the other end [MA-A region], reducing evidently the formation of layered structure along the direction, while increasing gradually the formation of spherical alumina particles. The CA6/(MA-A) region had a better toughness that could prevent the crack propagation and improve the spalling resistance. Meanwhile, the MA-A region could provide structural support, because of the higher Vickers hardness and density. [ABSTRACT FROM AUTHOR]

Calcium hexaluminate (CA6) was incorporated into the matrix of magnesio aluminate spinel-alumina (MA-A) via infiltration of a porous preform fabricated from a-Al2O3 and MgO powders with a saturated calcium acetate solution and subsequent firing, forming CA6/(MA-A) functionally composites with graded fracture toughness. Actually, the porous preform was partially and perpendicularly immersed (1/4 of its length) in the solution. Owing to the capillary action, the calcium acetate solution was absorbed into the porous preform, and the different absorption distance led to the graded solution concentration in the height direction of the porous preform. The in-situ formation of CA6 conferred graded microstructures, as well as improved mechanical properties on the resultant composites. The CA6 content decreased gradually along the solution absorption direction, i.e., from one end [CA6/(MA-A) region] immersed in solution to the other end [MA-A region], reducing evidently the formation of layered structure along the direction, while increasing gradually the formation of spherical alumina particles. The CA6/(MA-A) region had a better toughness that could prevent the crack propagation and improve the spalling resistance. Meanwhile, the MA-A region could provide structural support, because of the higher Vickers hardness and density. [ABSTRACT FROM AUTHOR]

Bars: 25 m. (e,f) The corresponding parameter of TRAP and the serum bone resorption marker detected by enzyme-linked immunosorbent assay (ELISA) showed that miR-21 deficiency blocked age-related osteoclastogenesis and bone resorption. (d) Enzyme-linked immunosorbent assay (ELISA) detection of the serum bone resorption marker of 3-month WT and miR-21-/- mice. miR-21 deficiency inhibited the bone resorption rate. [Extracted from the article]

Perchlorate and chlorate are present in various extraterrestrial celestial bodies throughout the solar system, such as Mars, the moon, and asteroids. To date, the origin mechanisms of perchlorate and chlorate on the Martian surface have been well-established; however, relatively little attention has been cast to airless bodies. Here, we experimentally investigated the potential oxidation mechanisms of chloride to chlorate and perchlorate, such as ultraviolet irradiation under H2O- and O2-free conditions and mechanical pulverization processes. Individual minerals, olivine, pyroxene, ilmenite, magnetite, TiO2 and anhydrous ferric sulfate, and lunar regolith simulants (low Ti, CLRS-1; high-Ti, CLRS-2) and their metallic iron (Fe0) bearing counterparts were examined. We found that pulverization of dry matrix material-halite mixtures, even in the presence of O2, does not necessarily lead to perchlorate and chlorate formation without involving water. Under photocatalytic and H2O- and O2-free conditions, olivine and pyroxene can produce oxychlorine (ClOx−) species, although the yields were orders of magnitude lower than those under Martian-relevant conditions. Nanophase-Fe0 particles in the lunar regolith and the common photocatalyst TiO2 can facilitate the ClOx− formation, but their yields were lower than those with olivine. The oxides ilmenite and magnetite did not efficiently contribute to ClOx− production. Our results highlight the critical role of H2O in the oxidation chloride to chlorate and perchlorate, and provide essential insights into the environmental influence on the formation of oxychlorine species on different celestial bodies. [ABSTRACT FROM AUTHOR]

Preparation of nanomaterials with various morphologies and exploiting their novel physical properties are of vital importance in nanoscientific field. Similarly to the III-N compound semiconductors, Si3N4 nanostructures also could be potentially used for making optoelectronic devices. In this paper, we report on an improved Fe-catalyzed chemical vapour deposition method for synthesizing ultra-long α-Si3N4 nanobelts along with a few nanowires and nanobranches on a carbon felt substrate. The ultra-long α-Si3N4 nanobelts grew via a combined VLS-base and nanobranches via a combined double-stage VLS-base and VS-tip mechanism, as well as nanowires via VLS-tip mechanism. The three individual nanostructures showed variant optical properties as revealed by a cathodoluminescence spectroscopy. A single α-Si3N4 nanobelt or nanobranch gave a strong UV-blue emission band as well as a broad red emission, whereas a single α-Si3N4 nanowire exhibited only a broad UV-blue emission. The results reported would be useful in developing new photoelectric nanodevices with tailorable or tunable properties. [ABSTRACT FROM AUTHOR]

MicroRNAs emerge as critical post-transcriptional regulators in bone metabolism. We have previously reported in vitro that miR-21 promotes osteogenesis, while studies have also revealed miR-21 as a regulator of osteoclastogenesis and a promoter of osteoclast differentiation in vitro. However, in vivo data are still lacking in identifying skeletal function of miR-21, particularly its effects on osteoporosis. Here, using miR-21 knockout (miR-21−/−) mice, we investigated effects of miR-21 on bone development, bone remodeling and bone loss. Unexpectedly, miR-21−/− mice demonstrated normal skeletal phenotype in development and maintained osteoblastogenesis in vivo. Besides, miR-21−/− mice showed increased receptor activator of nuclear factor κB ligand (RANKL) and decreased osteoprotegerin (OPG) through miR-21 targeting Sprouty 1 (Spry1). Nevertheless, interestingly, miR-21 deficiency promoted trabecular bone mass accrual physiologically. Furthermore, in pathological states, the protection of bone mass was prominent in miR-21−/− mice. These skeletal effects were attributed to inhibition of bone resorption and osteoclast function by miR-21 deficiency through miR-21 targeting programmed cell death 4 (PDCD4), despite the existence of RANKL. As far as we know, this is the first in vivo evidence of a pro-osteoclastic microRNA. Together, these findings clarified function of miR-21 in bone metabolism, particularly uncovering osteo-protective potential of miR-21 inactivation in osteoporosis. [ABSTRACT FROM AUTHOR]

Introduction: The most reliable liver safety signal in a clinical trial is considered to be 'Hy's Law cases' defined as subjects experiencing hepatocellular injury and serum bilirubin elevations with no more likely cause than study drug. However, there is little published data to support the current biochemical criteria for Hy's Law cases or their use to estimate postmarketing risk of severe liver injury. Objectives: The primary objective of this study was to identify and characterize Hy's Law cases in patients treated for tuberculosis (TB). A secondary objective was to identify patient risk factors for drug-induced liver injuries. Methods: We utilized eDISH (evaluation of Drug-Induced Serious Hepatoxicity) to retrospectively analyze data from 517 patients treated for activeTB, a regimen well known to be capable of causing severe hepatotoxicity. Results: We identified two Hy's Law cases, which is consistent with the treatment's known risk of liver failure. Despite monthly monitoring, neither Hy's Law case experienced a documented elevation in serum alanine aminotransferase exceeding 10 × upper limits of normal. Hepatoprotectant use and infection with chronic hepatitis B were associated with increased risk of liver injury. Conclusions: Our observations support the current biochemical criteria for Hy's Law cases and their use to estimate postmarketing risk. [ABSTRACT FROM AUTHOR]

Crystalline semiconductor nanomembranes (NMs), which are transferable, stackable, bondable and manufacturable, offer unprecedented opportunities for unique and novel device applications. We review here nanophotonic devices based on stacked semiconductor NMs on Si, glass and flexible PET substrates. Photonic crystal Fano resonance-based surface-normal optical filters and broadband reflectors have been demonstrated with unique angle and polarization properties. Flexible photodetectors and solar cells have also been developed based on the NM stacking processes. Such NM stacking process can lead to a paradigm shift on silicon photonic integration and hybrid organic/inorganic flexible photonics. [ABSTRACT FROM AUTHOR]

MicroRNAs emerge as critical post-transcriptional regulators in bone metabolism. We have previously reported in vitro that miR-21 promotes osteogenesis, while studies have also revealed miR-21 as a regulator of osteoclastogenesis and a promoter of osteoclast differentiation in vitro. However, in vivo data are still lacking in identifying skeletal function of miR-21, particularly its effects on osteoporosis. Here, using miR-21 knockout (miR-21−/−) mice, we investigated effects of miR-21 on bone development, bone remodeling and bone loss. Unexpectedly, miR-21−/− mice demonstrated normal skeletal phenotype in development and maintained osteoblastogenesis in vivo. Besides, miR-21−/− mice showed increased receptor activator of nuclear factor κB ligand (RANKL) and decreased osteoprotegerin (OPG) through miR-21 targeting Sprouty 1 (Spry1). Nevertheless, interestingly, miR-21 deficiency promoted trabecular bone mass accrual physiologically. Furthermore, in pathological states, the protection of bone mass was prominent in miR-21−/− mice. These skeletal effects were attributed to inhibition of bone resorption and osteoclast function by miR-21 deficiency through miR-21 targeting programmed cell death 4 (PDCD4), despite the existence of RANKL. As far as we know, this is the first in vivo evidence of a pro-osteoclastic microRNA. Together, these findings clarified function of miR-21 in bone metabolism, particularly uncovering osteo-protective potential of miR-21 inactivation in osteoporosis. [ABSTRACT FROM AUTHOR]