Efficient Fabrication of Quartz Glass Using Laser Coaxial Powder-Fed Additive Manufacturing Approach.

This article investigates a laser-directed energy deposition additive manufacturing (AM) method, based on coaxial powder feeding, for preparing quartz glass. Through synergistic optimization of line deposition and plane deposition experiments, key parameters of laser coaxial powder feeding AM were identified. The corresponding mechanical properties, thermal properties, and microstructure of the bulk parts were analyzed. The maximum mechanical strength of the obtained quartz glass element reached 72.36 ± 5.98 MPa, which is ca. 95% that of quartz glass prepared by traditional methods. The thermal properties of the obtained quartz glass element were also close to those prepared by traditional methods. The present research indicates that one can use laser AM technology that is based on coaxial powder feeding to form quartz glass with high density and good thermodynamic properties. Such quartz glass has substantial potential in, for example, optics and biomedicine.

Microbial life-history strategies mediate microbial carbon pump efficacy in response to N management depending on stoichiometry of microbial demand.

The soil microbial carbon pump (MCP) is increasingly acknowledged as being directly linked to soil organic carbon (SOC) accumulation and stability. Given the close coupling of carbon (C) and nitrogen (N) cycles and the constraints imposed by their stoichiometry on microbial growth, N addition might affect microbial growth strategies with potential consequences for necromass formation and carbon stability. However, this topic remains largely unexplored. Based on two multi-level N fertilizer experiments over 10 years in two soils with contrasting soil fertility located in the North (Cambisol, carbon-poor) and Southwest (Luvisol, carbon-rich), we hypothesized that different resource demands of microorganism elicit a trade-off in microbial growth potential (Y-strategy) and resource-acquisition (A-strategy) in response to N addition, and consequently on necromass formation and soil carbon stability. We combined measurements of necromass metrics (MCP efficacy) and soil carbon stability (chemical composition and mineral associated organic carbon) with potential changes in microbial life history strategies (assessed via soil metagenomes and enzymatic activity analyses). The contribution of microbial necromass to SOC decreased with N addition in the Cambisol, but increased in the Luvisol. Soil microbial life strategies displayed two distinct responses in two soils after N amendment: shift toward A-strategy (Cambisol) or Y-strategy (Luvisol). These divergent responses are owing to the stoichiometric imbalance between microbial demands and resource availability for C and N, which presented very distinct patterns in the two soils. The partial correlation analysis further confirmed that high N addition aggravated stoichiometric carbon demand, shifting the microbial community strategy toward resource-acquisition which reduced carbon stability in Cambisol. In contrast, the microbial Y-strategy had the positive direct effect on MCP efficacy in Luvisol, which greatly enhanced carbon stability. Such findings provide mechanistic insights into the stoichiometric regulation of MCP efficacy, and how this is mediated by site-specific trade-offs in microbial life strategies, which contribute to improving our comprehension of soil microbial C sequestration and potential optimization of agricultural N management.

B(C6F5)3-Catalyzed Formal (n + 3) (n = 5 and 6) Cycloaddition of Bicyclo[1.1.0]butanes to Medium Bicyclo[n.1.1]alkanes.

Herein, a B(C6F5)3-catalyzed formal (n + 3) (n = 5 and 6) cycloaddition of bicyclo[1.1.0]butanes (BCBs) with imidazolidines/hexahydropyrimidines is described. The reaction provides a modular, atom-economical, and efficient strategy to two libraries of synthetically challenging medium-bridged rings, 2,5-diazabicyclo[5.1.1]nonanes and 2,6-diazabicyclo[6.1.1]decanes, in moderate to excellent yields. This reaction also features simple operation, mild reaction conditions, and broad substrate scope. A scale-up experiment and various synthetic transformations of products further highlight the synthetic utility.

Metastasis-associated 1 localizes to the sarcomeric Z-disc and is implicated in skeletal muscle pathology.

Metastasis-associated 1 (MTA1), a subunit of the nucleosome remodeling and histone deacetylation (NuRD) corepressor complex, was reported to be expressed in the cytoplasm of skeletal muscles. However, the exact subcellular localization and the functional implications of MTA1 in skeletal muscles have not been examined. This study aims to demonstrate the subcellular localization of MTA1 in skeletal muscles and reveal its possible roles in skeletal muscle pathogenesis. Striated muscles (skeletal and cardiac) from C57BL/6 mice of 4-5 weeks were collected to examine the expression of MTA1 by Western blotting and immunohistochemistry. Immunofluorescence and immunoelectron microscopy were performed for MTA1, α-actinin (a Z-disc marker protein), and SMN (survival of motor neuron) proteins. Gene Expression Omnibus (GEO) data sets were analyzed using the GEO2R online tool to explore the functional implications of MTA1 in skeletal muscles. MTA1 expression was detected by Western blotting and immunohistochemistry in skeletal and cardiac muscles. Subcellular localization of MTA1 was found in the Z-disc of sarcomeres, where α-actinin and SMN were expressed. Data mining of GEO profiles suggested that MTA1 dysregulation is associated with multiple skeletal muscle defects, such as Duchenne muscular dystrophy, Emery-Dreifuss muscular dystrophy, nemaline myopathy, and dermatomyositis. The GEO analysis also showed that MTA1 expression gradually decreased with age in mouse skeletal muscle precursor cells. The subcellular localization of MTA1 in sarcomeres of skeletal muscles implies its biological roles in sarcomere structures and its possible contribution to skeletal muscle pathology.

Silver Nanowires-Based Flexible Gold Electrode Overcoming Interior Impedance of Nanomaterial Electrodes.

In the development of nanomaterial electrodes for improved electrocatalytic activity, much attention is paid to the compositions, lattice, and surface morphologies. In this study, a new concept to enhance electrocatalytic activity is proposed by reducing impedance inside nanomaterial electrodes. Gold nanodendrites (AuNDs) are grown along silver nanowires (AgNWs) on flexible polydimethylsiloxane (PDMS) support. The AuNDs/AgNWs/PDMS electrode affords an oxidative peak current density of 50 mA cm-2 for ethanol electrooxidation, a value ≈20 times higher than those in the literature do. Electrochemical impedance spectroscopy (EIS) demonstrates the significant contribution of the AgNWs to reduce impedance. The peak current densities for ethanol electrooxidation are decreased 7.5-fold when the AgNWs are electrolytically corroded. By in situ surface-enhanced Raman spectroscopy (SERS) and density functional theory (DFT) simulation, it is validated that the ethanol electrooxidation favors the production of acetic acid with undetectable CO, resulting in a more complete oxidation and long-term stability, while the AgNWs corrosion greatly decreases acetic acid production. This novel strategy for fabricating nanomaterial electrodes using AgNWs as a charge transfer conduit may stimulate insights into the design of nanomaterial electrodes.

Isolation, structure modification, and anti-rheumatoid arthritis activity of isopimarane-type diterpenoids from Orthosiphon aristatus.

Orthosiphon aristatus is a well-known folkloric medicine and herb for Guangdong soup for the treatment of rheumatism in China. Eight isopimarane-type and migrated pimarane-type diterpenoids (1-8), including a new one with a rarely occurring α,ß-unsaturated diketone C-ring, were isolated from O. aristatus. Their structures were determined by spectroscopic methods and quantum chemical calculations. Furthermore, the most abundant compound, orthosiphol K, was structurally modified by modern synthetic techniques to give seven new derivatives (9-15). The anti-rheumatoid arthritis activity of these diterpenoids were evaluated on a TNF-α induced MH7A human rheumatoid fibroblast-like synoviocyte model. Compound 10 showed the most potent activity among these compounds. Based on their inhibitory effects on the release levels of IL-1ß, the preliminary structure-activity relationships were concluded. Furthermore, western blot analysis revealed that 10 could increase the expression of IκBα and decrease the expression of NF-κB p65, and the expression levels of COX-2 and NLRP3 proteins were consequently down-regulated.

Stereocontrol of C-N Axial and Spiro-Central Chirality via Rh(II)-Catalyzed Enantioselective N-H Bond Insertion of Indolinone-Spiroacetal.

A rhodium-catalyzed carbene N-H insertion protocol for simultaneously controlling the C-N axial and spiro-central chiralities is disclosed, resulting in the rapid assembly of enantiopure N-arylindolinone-spiroacetal derivatives in high yields with excellent enantioselectivities. This promising strategy features the chiral C-N axis, spiro-central chirality, functional group tolerance, and late-stage diversification. DFT calculations indicate that the N-H insertion is the axial-chirality-determining step and that the 1,5-H shift step is regiospecifically caused by the spirocycle.

Starvation-inactivated MTOR triggers cell migration via a ULK1-SH3PXD2A/TKS5-MMP14 pathway in ovarian carcinoma.

ABBREVIATIONS: AMPK: AMP-activated protein kinase; CHX: cycloheximide; RAD001: everolimus; HBSS: Hanks' balanced salt solution; LC-MS/MS: liquid chromatography-mass spectrometry/mass spectrometry; MMP14: matrix metallopeptidase 14; MTOR: mechanistic target of rapamycin kinase; MAPK: mitogen-activated protein kinase; RB1CC1/FIP200: RB1 inducible coiled-coil 1; PtdIns3P: phosphatidylinositol-3-phosphate; PX: phox homology; SH3: Src homology 3; SH3PXD2A/TKS5: SH3 and PX domains 2A; SH3PXD2A-[6A]: S112A S142A S146A S147A S175A S348A mutant; ULK1: unc-51 like autophagy activating kinase 1.

NHC-catalyzed [3 + 3] cycloaddition of α-bromoenals with nitroketene aminals or nitroketene N,S-acetals: synthesis of nitro-containing dihydropyridin-2-ones.

An N-heterocyclic carbene (NHC)-catalyzed [3 + 3] cycloaddition of α-bromoenals with nitroketene aminals or nitroketene N,S-acetals has been developed. This methodology provides an efficient strategy for the construction of valuable nitro-containing heterocyclic compounds. This protocol features mild reaction conditions, easily available starting materials, broad substrate scope and easy scalability.

Novel Flexible Ag/AgCl Quasi-Reference Electrode with Fishbone Nanowire Structure for Remarkable Potential Stability, Long-Term Reliability, and Noninvasive Electrocardiography.

The roadblocks for the planar silver/silver chloride (Ag/AgCl) quasi-reference electrode (qRE) development are the potential stability and long-term reliability as potentiometric sensors. Although there is a significant amount of work on potentiometric screen-printed and inkjet-printed sensors, none of the REs has comparable performance to that of the conventional glass RE and knowledge on reliable planar Ag/AgCl qREs is still limited. Here, a novel fishbone-structured flexible Ag/AgCl qRE (Fishbone-Ag/AgCl qRE) was developed and its stability and long-term reliability were significantly improved. The stability of the Fishbone-Ag/AgCl qRE was comparable to that of a commercial glass Ag/AgCl RE. In a long-term stability test, the Fishbone-Ag/AgCl qRE could continuously and stably operate for more than 4 h. Shelf-life testing revealed a 6 month life span. The conductivity and diameter of the nanowires in the fishbone structure of the Ag/AgCl qRE had important influences on electrochemical properties. The conductivity of the qRE influenced the charge-transfer rate in the electrode so that it affected the potential stability. Thicker diameter and slight chlorination on the surface of the AgNWs resulted in enhanced long-term reliability of the qRE. The capabilities of this new nanostructured material were applied in vivo for noninvasive monitoring of electrocardiogram. The discovery is elementary and substantially informs improved nanostructure RE design for testing and commercial medical device applications.

phoD-harboring bacterial community composition dominates organic P mineralization under long-term P fertilization in acid purple soil.

Introduction: A better understanding of the regulatory role of microorganisms on soil phosphorous (P) mobilization is critical for developing sustainable fertilization practices and reducing P resource scarcity. The phoD genes regulate soil organic P (Po) mobilization. Methods: Based on the long-term P application experiments in acid purple soil of maize system in Southwest China (started in 2010), the experiment included five P levels: 0, 16, 33, 49, and 65.5 kg P hm-2 (P0, P16, P33, P49, and P65.5, respectively). The molecular speciation of organic P in soil was determined by 31P-nuclear magnetic resonance (NMR), high-throughput sequencing technology, and real-time qPCR were used to analyze the bacterial community and abundance of phoD-harboring bacterial genes, exploring the bacterial community and abundance characteristics of phoD gene and its relationship with the forms of Po and alkaline phosphatase (ALP) activity in the soil. Results: The results showed that the orthophosphate monoesters (OM) were the main Po speciation and varied by P fertilization in acid purple soil. ALP activity decreased as P fertilization increased. Co-occurrence network analysis identified the overall network under five P fertilizations. The keystone taxon base on the network showed that Collimonas, Roseateles, Mesorhizobium, and Cellulomonas positively correlated with both OM and Po. The random forest showed that Cellulomonas, Roseateles, and Rhodoplanes were the key predictors for ALP activity. The keystone taxon was a more important predictor than the dominant taxon for ALP, OM, and Po. The structural equation model (SEM) showed that soil organic matter (SOM), available P (AP), and OM were the main factors influencing the ALP by reshaping phoD-harboring bacteria alpha diversity, community composition, and phoD abundance. Discussion: The phoD-harboring bacterial community composition especially the keystone taxon rather than alpha diversity and abundance dominated the ALP activity, which could promote P utilization over an intensive agroecosystem. These findings improve the understanding of how long-term gradient fertilization influences the community composition and function of P-solubilizing microorganisms in acid purple soil.

Unexpected Copper-Catalyzed Cascade Reaction of 1,6-Enynes with Sulfoxonium Ylides.

An unprecedented copper-catalyzed cascade reaction of 1,6-enynes with sulfoxonium ylides is reported, providing a series of structurally intriguing 2,3-disubstituted indolines bearing a conjugated dienone functionality at the 3-position in moderate to excellent yields with good chemo-, regio-, and diastereoselectivities under mild reaction conditions. Importantly, sulfoxonium-ylide-derived copper-carbene herein exhibits quite different reactivity from that of diazo copper-carbene. A rational mechanism, an initial ammonium ylide rather than allene formation, is proposed.

Copper-Catalyzed Cycloadditions of Diazo Compounds with Imidazolidines/Hexahydropyrimidines for the Syntheses of N-Heterocycles.

Reported herein are the unprecedented copper-catalyzed formal [n + 1]/[n + 3] (n = 5, 6) cycloadditions of diazo compounds with imidazolidines/hexahydropyrimidines, thus providing a general, economical, and efficient route to construct different sized (six- to nine-membered) diaza-heterocycles in moderate to excellent yields under mild reaction conditions. This strategy features the use of copper catalyst to accomplish such diverse annulations and the utilization of imidazolidines/hexahydropyrimidines as stable 1,5-/1,6-dipoles.

Anemia, hematinic deficiencies, and hyperhomocysteinemia in younger and older burning mouth syndrome patients.

Abstract Background/purpose: Our previous study found that 19.8%, 16.2%, 4.8%, 2.3%, and 19.2% of 884 burning mouth syndrome (BMS) patients have anemia, serum iron, vitamin B12, and folic acid deficiencies, and hyperhomocysteinemia, respectively. This study mainly evaluated the anemia, hematinic deficiencies, and hyperhomocysteinemia in 272 younger (≤50 years old) and 612 older (>50 years old) BMS patients. Materials and methods: The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, and homocysteine levels in 272 younger and 612 older BMS patients were measured and compared with the corresponding levels in 136 younger (≤50 years old) and 306 older (>50 years old) healthy control subjects (HCSs), respectively. Results: We found that 272 younger BMS patients had significantly lower mean blood Hb and serum iron, vitamin B12, and folic acid levels than 136 younger HCSs. Moreover, 612 older BMS patients had significantly lower mean blood Hb, and serum iron and vitamin B12 levels and significantly higher mean serum homocysteine level than 306 older HCSs. In addition, 272 younger BMS patients had higher mean blood Hb level (marginal significance, P = 0.056), significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of iron and folic acid deficiencies than 612 older BMS patients. Conclusion: The younger BMS patients do have higher mean blood Hb level, significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of serum iron and folic acid deficiencies than the older BMS patients.

PIDA-Promoted/HFIP-Controlled Dearomative Spirocyclization of Phenolic Ketones via a Spirocyclohexadienone-Oxocarbenium Cation Species.

A phenyliodine(III) diacetate-promoted/1,1,1,3,3,3-hexafluoroisopropanol-controlled dearomative spirocyclization of phenolic ketones was reported, providing two libraries of structurally interesting scaffolds, spirocyclohexadienonic ketals and their acetoxylated counterparts, in moderate to excellent yields under mild conditions. Control experiments unravel that the reaction proceeds through a spirocyclohexadienone-oxocarbenium cation species. In addition, an in situ-generated hypervalent iodine(III)-catalyzed version, as well as the late-stage transformation of products via conjugate additions, was also realized.

Enantioselective Synthesis of α-Aryl-ß-Aminocyclopropane Carboxylic Acid Derivatives via Rh(II)-Catalyzed Cyclopropanation of Vinylsulfonamides with α-Aryldiazoesters.

The reaction of vinylsulfonamides with donor-acceptor carbenes derived from α-aryldiazoesters, catalyzed by the tert-butyl glycine-derived dirhodium complex Rh2(S-4-Br-NTTL)4, has been reported. This method provides a variety of α-aryl-ß-aminocyclopropane carboxylic acid derivatives bearing one quaternary carbon stereogenic center vicinal to the amino-substituted carbon in high yields with excellent diastereo- and enantioselectivities. Vinylsulfonamides showed complementary advantages over the well-developed vinylamides or vinylcarbamates for this Rh(II)-catalyzed cyclopropanation strategy. Moreover, these conformationally restricted α-aryl-ß-aminocyclopropyl carboxylic acid derivatives can be readily incorporated into dipeptides.