Self-Catalyzed Hydrogenated Carbon Nano-Onions Facilitates Mild Synthesis of Transparent Nano-Polycrystalline Diamond.

Transparent nano-polycrystalline diamond (t-NPD) possesses superior mechanical properties compared to single and traditional polycrystalline diamonds. However, the harsh synthetic conditions significantly limit its synthesis and applications. In this study, a synthesis routine is presented for t-NPD under low pressure and low temperature conditions, 10 GPa, 1600 °C and 15 GPa, 1350 °C similar with the synthesis condition of organic precursor. Self-catalyzed hydrogenated carbon nano-onions (HCNOs) from the combustion of naphthalene enable synthesis under nearly industrial conditions, which are like organic precursor and much lower than that of graphite and other carbon allotropes. This is made possible thanks to the significant impact of hydrogen on the thermodynamics, as it chemically facilitates phase transition. Ubiquitous nanotwinned structures are observed throughout t-NPD due to the high concentration of puckered layers and stacking faults of HCNOs, which impart a Vickers hardness about 140 GPa. This high hardness and optical transparency can be attributed to the nanocrystalline grain size, thin intergranular films, absence of secondary phase and pore-free features. The facile and industrial-scale synthesis of the HCNOs precursor, and mild synthesis conditions make t-NPD suitable for a wide range of potential applications.

Effect of Interfacial Action on the Generation and Transformation of Reactive Oxygen Species in Tripolyphosphate-Enhanced Heterogeneous Fe3O4/O2 Systems.

It has been reported that tripolyphosphate (TPP) can enhance the oxygenation of natural Fe(II)-containing minerals to produce reactive oxygen species (ROS). However, the molecular structure of the TPP-Fe(II) mineral surface complex and the role of this complex in the generation and transformation of ROS have not been fully characterized. In the present study, a heterogeneous magnetite (Fe3O4)/O2/TPP system was developed for the degradation of p-nitrophenol (PNP). The results showed that the addition of TPP significantly accelerated the removal of PNP in the Fe3O4/O2 system and extended the range of effective pH to neutral. Experiments combined with density functional theory calculations revealed that the activation of O2 mainly occurs on the surface of Fe3O4 induced by a structural Fe(II)-TPP complex, where the generated O2•- (intermediate active species) can be rapidly converted into H2O2, and then the •OH generated by the Fenton reaction is released into the solution. This increases the concentration of •OH produced and the efficiency of •OH produced relative to Fe(II) consumed, compared with the homogeneous system. Furthermore, the binding of TPP to the surface of Fe3O4 led to stretching and even cleavage of the Fe-O bonds. Consequently, more Fe(II)/(III) atoms are exposed to the solvation environment and are available for the binding of active O2 and O2•-. This study demonstrates how common iron minerals and O2 in the natural environment can be combined to yield a green remediation technology.

New insights into long-lasting Cr(VI) removal from groundwater using in situ biosulfidated zero-valent iron with sulfate-reducing bacteria.

Sulfidation enhances the reactivity of zero-valent iron (ZVI) for Cr(VI) removal from groundwater. Current sulfidation methods mainly focus on chemical and mechanical sulfidation, and there has been little research on biosulfidation using sulfate-reducing bacteria (SRB) and its performance in Cr(VI) removal. Herein, the ability of the SRB-biosulfidated ZVI (SRB-ZVI) system was evaluated and compared with that of the Na2S-sulfidated ZVI system. The SRB-ZVI system forms a thicker and more porous FeSx layer than the Na2S-sulfidated ZVI system, resulting in more sufficient sulfidation of ZVI and a 2.5-times higher Cr(VI) removal rate than that of the Na2S-sulfidated ZVI system. The biosulfidated-ZVI granules and FeSx suspension are the major components of the SRB-ZVI system. The SRB-ZVI system exhibits a long-lasting (11 cycles) Cr(VI) removal performance owing to the regeneration of FeSx. However, the Na2S-sulfidated ZVI system can perform only two Cr(VI) removal cycles. SRB attached to biosulfidated-ZVI can survive in the presence of Cr(VI) because of the protection of the biogenic porous structure, whereas SRB in the suspension is inhibited. After Cr(VI) removal, SRB repopulates in the suspension from biosulfidated-ZVI and produce FeSx, thus providing conditions for subsequent Cr(VI) removal cycles. Overall, the synergistic effect of SRB and ZVI provides a more powerful and environmentally friendly sulfidation method, which has more advantageous for Cr(VI) removal than those of chemical sulfidation. This study provides a visionary in situ remediation strategy for groundwater contamination using ZVI-based technologies.

Papillary thyroid cancer organoids harboring BRAFV600E mutation reveal potentially beneficial effects of BRAF inhibitor-based combination therapies.

BACKGROUNDS: Papillary thyroid cancer (PTC), which is often driven by acquired somatic mutations in BRAF genes, is the most common pathologic type of thyroid cancer. PTC has an excellent prognosis after treatment with conventional therapies such as surgical resection, thyroid hormone therapy and adjuvant radioactive iodine therapy. Unfortunately, about 20% of patients develop regional recurrence or distant metastasis, making targeted therapeutics an important treatment option. Current in vitro PTC models are limited in representing the cellular and mutational characteristics of parental tumors. A clinically relevant tool that predicts the efficacy of therapy for individuals is urgently needed. METHODS: Surgically removed PTC tissue samples were dissociated, plated into Matrigel, and cultured to generate organoids. PTC organoids were subsequently subjected to histological analysis, DNA sequencing, and drug sensitivity assays, respectively. RESULTS: We established 9 patient-derived PTC organoid models, 5 of which harbor BRAFV600E mutation. These organoids have been cultured stably for more than 3 months and closely recapitulated the histological architectures as well as mutational landscapes of the respective primary tumors. Drug sensitivity assays of PTC organoid cultures demonstrated the intra- and inter-patient specific drug responses. BRAFV600E inhibitors, vemurafenib and dabrafenib monotherapy was mildly effective in treating BRAFV600E-mutant PTC organoids. Nevertheless, BRAF inhibitors in combination with MEK inhibitors, RTK inhibitors, or chemotherapeutic agents demonstrated improved efficacy compared to BRAF inhibition alone. CONCLUSIONS: These data indicate that patient-derived PTC organoids may be a powerful research tool to investigate tumor biology and drug responsiveness, thus being useful to validate or discover targeted drug combinations.

High-Temperature Superconducting Phase in Clathrate Calcium Hydride CaH_{6} up to 215 K at a Pressure of 172 GPa.

The recent discovery of superconductive rare earth and actinide superhydrides has ushered in a new era of superconductivity research at high pressures. This distinct type of clathrate metal hydrides was first proposed for alkaline-earth-metal hydride CaH_{6} that, however, has long eluded experimental synthesis, impeding an understanding of pertinent physics. Here, we report successful synthesis of CaH_{6} and its measured superconducting critical temperature T_{c} of 215 K at 172 GPa, which is evidenced by a sharp drop of resistivity to zero and a characteristic decrease of T_{c} under a magnetic field up to 9 T. An estimate based on the Werthamer-Helfand-Hohenberg model gives a giant zero-temperature upper critical magnetic field of 203 T. These remarkable benchmark superconducting properties place CaH_{6} among the most outstanding high-T_{c} superhydrides, marking it as the hitherto only clathrate metal hydride outside the family of rare earth and actinide hydrides. This exceptional case raises great prospects of expanding the extraordinary class of high-T_{c} superhydrides to a broader variety of compounds that possess more diverse material features and physics characteristics.

Erratum: High-Temperature Superconducting Phase in Clathrate Calcium Hydride CaH_{6} up to 215 K at a Pressure of 172 GPa [Phys. Rev. Lett. 128, 167001 (2022)].

This corrects the article DOI: 10.1103/PhysRevLett.128.167001.

Tissue Engineering Material KLD-12 Polypeptide /TGF-ß1 the Protective Effect and Mechanism of Nanofiber Gel on Early Intervertebral Disc Degeneration.

Intervertebral disc degeneration (IDD) is a common clinical symptom of multifactorial disease. The treatment and expenditure of IDD cause huge economic and psychological harm to patients, and there is no root treatment in the clinic. However, the appearance of tissue engineering materials provides a new idea for the treatment of early IDD. KLD-12 polypeptide material is a new kind of polypeptide scaffold material, which can be used to repair early IDD and TGF-ß1Transforming growth factor-1 plays an important role in the proliferation of Intervertebral disc cells and inhibition of inflammatory response. In order to further understand the tissue engineering material kld-12 polypeptide / TGF-ß1 the biomechanical properties of nanofiber gel, and to clarify tissue engineering material KLD-12 polypeptide TGF-ß1nanofiber gel provides an experimental basis for the protection and mechanism of early IDD. In this paper, tissue engineering material KLD-12 polypeptide /TGF-ß1 is mainly studied as the protective effect and mechanism of nanofiber gel on early IDD. In this paper, through the study of the tissue structure of the intervertebral disc, the composition of the nucleus pulposus, annulus fibrosus and cartilage endplate was studied. The objective was to study the relationship between transforming growth factor TGF-ß1 and IDD and to understand its important role in the proliferation of intervertebral disc cells and inhibition of inflammatory response. In this paper, we studied the molecular basis of IDD, the main reason is the imbalance of extracellular matrix synthesis and degradation of Intervertebral disc cells, to understand the structural characteristics of cartilage endplate and the composition of Intervertebral disc fibroblasts. In this study, we studied the cell proliferation activity, the ratio of surviving dead cells, the content of glucosaminoglycans, the content of polyproteoglycan and type II collagen in the gel, and studied the protective effect and mechanism of tissue engineering material KLD-12 polypeptide /TGF-ß1 nanofiber gel on early IDD. The results showed that kld-12 polypeptide / TGF-ß1 was more effective in the proliferation activity of annulus fibrosus cells of nanofiber gel is higher than that of KLD-12 polypeptide/annulus fibroin nanofiber gel. On 2d, the difference in cell proliferation activity was not obvious, KLD-12 polypeptide / TGF- ß 1 the fibrous annulus cell proliferation activity of nanofiber gel was 0.796, and the proliferation activity of KLD-12 polypeptide/annulus fibroin nanofiber gel was 0.786. On the 14d, KLD-12 polypeptide / TGF- ß 1 the fibrous annulus cell proliferation activity of nanofiber gel was 1.204, and the proliferation activity of KLD-12 polypeptide/annulus fibroin nanofiber gel was 1.034.

Enhanced Photocurrent of All-Inorganic Two-Dimensional Perovskite Cs2PbI2Cl2 via Pressure-Regulated Excitonic Features.

Pressure processing is efficient to regulate the structural and physical properties of two-dimensional (2D) halide perovskites which have been emerging for advanced photovoltaic and light-emitting applications. Increasing numbers of studies have reported pressure-induced and/or enhanced emission properties in the 2D halide perovskites. However, no research has focused on their photoresponse properties under pressure tuning. It is also unclear how structural change affects their excitonic features, which govern the optoelectronic properties of the halide perovskites. Herein, we report significantly enhanced photocurrents in the all-inorganic 2D perovskite Cs2PbI2Cl2, achieving over 3 orders of magnitude increase at the industrially achievable level of 2 GPa in comparison with its initial photocurrent. Lattice compression effectively regulates the excitonic features of Cs2PbI2Cl2, reducing the exciton binding energy considerably from 133 meV at ambient conditions to 78 meV at 2.1 GPa. Impressively, such a reduced exciton binding energy of 2D Cs2PbI2Cl2 is comparable to the values of typical 3D perovskites (MAPbBr3 and MAPbI3), facilitating the dissociating of excitons into free carriers and enhancing the photocurrent. Further pressurization leads to a layer-sliding-induced phase transition and an anomalous negative linear compression, which has not been observed so far in other halide perovskites. Our findings reveal the dramatically enhanced photocurrents in the 2D halide perovskite by regulating its excitonic features and, more broadly, provide new insights into materials design toward extraordinary properties.

Comparative physiological and transcriptomic analyses reveal ascorbate and glutathione coregulation of cadmium toxicity resistance in wheat genotypes.

BACKGROUND: Cadmium (Cd) is a heavy metal with high toxicity that severely inhibits wheat growth and development. Cd easily accumulates in wheat kernels and enters the human food chain. Genetic variation in the resistance to Cd toxicity found in wheat genotypes emphasizes the complex response architecture. Understanding the Cd resistance mechanisms is crucial for combating Cd phytotoxicity and meeting the increasing daily food demand. RESULTS: Using two wheat genotypes (Cd resistant and sensitive genotypes T207 and S276, respectively) with differing root growth responses to Cd, we conducted comparative physiological and transcriptomic analyses and exogenous application tests to evaluate Cd detoxification mechanisms. S276 accumulated more H2O2, O2-, and MDA than T207 under Cd toxicity. Catalase activity and levels of ascorbic acid (AsA) and glutathione (GSH) were greater, whereas superoxide dismutase (SOD) and peroxidase (POD) activities were lower in T207 than in S276. Transcriptomic analysis showed that the expression of RBOHA, RBOHC, and RBOHE was significantly increased under Cd toxicity, and two-thirds (22 genes) of the differentially expressed RBOH genes had higher expression levels in S276 than inT207. Cd toxicity reshaped the transcriptional profiling of the genes involving the AsA-GSH cycle, and a larger proportion (74.25%) of the corresponding differentially expressed genes showed higher expression in T207 than S276. The combined exogenous application of AsA and GSH alleviated Cd toxicity by scavenging excess ROS and coordinately promoting root length and branching, especially in S276. CONCLUSIONS: The results indicated that the ROS homeostasis plays a key role in differential Cd resistance in wheat genotypes, and the AsA-GSH cycle fundamentally and vigorously influences wheat defense against Cd toxicity, providing insight into the physiological and transcriptional mechanisms underlying Cd detoxification.

Circ_0069718 promotes the progression of breast cancer by up-regulating NFIB through sequestering miR-590-5p.

Researches indicate that circular RNAs are dysregulated in breast cancer (BC) and play a critical role in regulating the malignant phenotype of cancer cells. Herein, the goal of this work was to investigate the role and mechanism of circ_0069718 in BC development. Levels of genes and proteins were detected by quantitative real-time polymerase chain reaction and western blot. In vitro experiments were performed using cell counting kit-8 assay, colony formation assay, EdU (5-ethynyl-2'-deoxyuridine) assay, flow cytometry, western blot, and transwell assay, respectively. The dual-luciferase reporter and RNA immunoprecipitation assays were used to identify the target relationship between miR-590-5p and circ_0069718 or nuclear factor I/B (NFIB). In vivo experiments were conducted using Xenograft model in mice. Circ_0069718 was up-regulated in BC tissues and cells. Knockdown of circ_0069718 suppressed BC cell apoptosis, migration, and invasion in vitro effectively. Mechanistically, circ_0069718 directly targeted miR-590-5p to up-regulate its target NFIB. Rescue experiments showed that miR-590-5p inhibition reversed the inhibitory effects of circ_0069718 knockdown on BC cell-aggressive oncogenic phenotypes; moreover, miR-590-5p re-expression restrained BC cell proliferation and mobility, which were abolished by NFIB up-regulation. Besides that, circ_0069718 silencing hindered tumor growth via miR-590-5p/NFIB axis in vivo. Circ_0069718 promotes BC progression by up-regulating NFIB through sequestering miR-590-5p, suggesting a potential therapeutic strategy in BC.

CircRNA CDR1as/miR-641/HOXA9 pathway regulated stemness contributes to cisplatin resistance in non-small cell lung cancer (NSCLC).

BACKGROUND: Cisplatin (DDP) is the first-line chemotherapeutic drug for non-small cell lung cancer (NSCLC), and long-term DDP stimulation increased resistance of NSCLC cells to this drug by enriching cancer stem cells (CSCs), which contributed to recurrence and worse prognosis of NSCLC, but the molecular mechanisms are still not fully delineated. METHODS: Real-Time qPCR and Western Blot analysis were conducted to examine gene expressions at mRNA and protein levels, respectively. Dual-luciferase reporter gene system was used to validate the targeting sites among circRNA CDR1as, miR-641 and HOXA9 mRNA. Cell growth was evaluated by CCK-8 assay, trypan blue staining assay and colony formation assay. The Annexin V-FITC/PI double staining method was employed to measure cell apoptosis ratio. Spheroid formation and flow cytometer assay was used to evaluate cell stemness. Xenograft mice models were established to measure tumorgenicity in vivo, and Ki67 expressions in mice tumor tissues were examined by immunohistochemistry (IHC). RESULTS: Here we identified a novel circRNA CDR1as/miR-641/Homeobox protein Hox-A9 (HOXA9) pathway regulated stemness and DDP chemoresistance in NSCLC. Mechanistically, circRNA CDR1as and HOXA9 were high-expressed, while miR-641 was low-expressed in DDP-resistant NSCLC cells, instead of their corresponding parental DDP-sensitive NSCLC cells. Additionally, we validated that circRNA CDR1as positively regulated HOXA9 in NSCLC cells by serving as an RNA sponge for miR-641, and knock-down of circRNA CDR1as increased the sensitivity of DDP-resistant NSCLC cells, which were reversed by downregulating miR-641 and upregulating HOXA9. Consistently, overexpression of circRNA CDR1as increased drug resistance of DDP-sensitive NSCLC cells by regulating miR-641/HOXA9 axis. In addition, the expression levels of stemness signatures (SOX2, OCT4 and Nanog) were higher in DDP-resistant NSCLC cells, which also tended to form spheres and enrich CD44+CD166+ population compared to their parental DDP-sensitive NSCLC cells, suggesting that CSCs were enriched in DDP-resistant NSCLC cells. Notably, knock-down of circRNA CDR1as inhibited stemness of DDP-resistant NSCLC cells by inhibiting HOXA9 through upregulating miR-641. CONCLUSIONS: Taken together, this study identified that circRNA CDR1as regulated stemness and DDP chemoresistance in NSCLC cells by targeting miR-641/HOXA9 axis.

Tricolor Ho

The photoluminescence (PL) characterization spectrum has been widely used to study the electronic energy levels. Ho^{3+} is one of the commonly used doping elements to provide the PL with concentration limited to 1% atomic ratio. Here, we present a tricolor PL achieved in pyrochlore Ho_{2}Sn_{2}O_{7} through pressure treatment at room temperature, which makes a non-PL material to a strong multiband PL material with Ho^{3+} at the regular lattice site with 18.2% concentration. Under a high pressure compression-decompression treatment up to 78.0 GPa, the Ho_{2}Sn_{2}O_{7} undergoes pyrochlore (Fd 3m), to cotunnite (Pnma), then amorphous phase transition with different Ho^{3+} coordinations and site symmetries. The PL emerged from 31.2 GPa when the pyrochlore to cotunnite phase transition took place with the breakdown of site symmetry and enhanced hybridization of Ho^{3+} 4f and 5d orbitals. Upon decompression, the materials became an amorphous state with a partial retaining of the defected cotunnite phase, accompanied with a large enhancement of red-dominant tricolor PL from the ion pair cross-relaxation effect in the low-symmetry (C_{1}) site, in which two distinct Ho^{3+} emission centers (S center and L center) are present.

Prediction of ammonia absorption in ionic liquids based on extreme learning machine modelling and a novel molecular descriptor SEP.

The large amounts of ammonia emissions generated from industrial production have caused serious environmental pollution problems, such as soil acidification, eutrophication, the formation of fine particles and changes in the global greenhouse balance, and also greatly endanger human health. At present, effectively reducing ammonia emissions or recovering ammonia is still a huge challenge. Ionic liquids (ILs) as a new class of green solvent have been introduced for ammonia absorption with great potential, but a huge number on combination systems of ILs lead to the difficulty of measuring the ammonia solubility in all ILs by experiments (e.g., danger and cost). Hereby, this study proposed a novel approach for estimating the ammonia solubility in different ILs. A predictive model was developed based on the novel Algorithm - extreme learning machine (ELM) and the molecular descriptors of electrostatic potential surface areas (SEP) as input parameters. Besides, 502 data points of ammonia solubility in 17 ILs were gathered with a wide range of pressure and temperature. For the total set, the determination coefficient (R2) and the average absolute relative deviation (AARD) of the developed model were 0.9937 and 2.95%, respectively. The regression plots revealed good consistency between predictive and experimental data points. Results show the good performance and reliability of the developed model, indicating that the proposed approach can be potentially applied for screening reasonable ILs to absorb ammonia from chemical industry processes.

Influence of the structure and composition of Fe-Mn binary oxides on rGO on As(III) removal from aquifers.

Fe-Mn binary oxide (FMBO) possesses high efficiency for As(III) abatement based on the good adsorption affinity of iron oxide and the oxidizing capacity of Mn(IV), and the composition and structure of FMBO play important roles in this process. To compare the removal performance and determine the optimum formula for FMBO, magnetic graphene oxide (MRGO)-FMBO and MRGO-MnO2 were synthesized with MRGO as a carrier to improve the dispersity of the adsorbents in aquifers and achieve magnetic recycling. Results indicated that MRGO-FMBO had higher As(III) removal than that of MRGO-MnO2, although the ratios of Fe and Mn were similar, because the binary oxide of Fe and Mn facilitated electron transfer from Mn(IV) to As(III), while the separation of Mn and Fe on MRGO-MnO2 restricted the process. The optimal stoichiometry x for MRGO-FMBO (MnxFe3-xO4) was 0.46, and an extraordinary adsorption capacity of 24.38 mg/g for As(III) was achieved. MRGO-FMBO showed stable dispersive properties in aquifers, and exhibited excellent practicability and reusability, with a saturation magnetization of 7.6 emu/g and high conservation of magnetic properties after 5 cycles of regeneration and reuse. In addition, the presence of coexisting ions would not restrict the practical application of MRGO-FMBO in groundwater remediation. The redox reactions of As(III) and Mn(IV) on MRGO-FMBO were also described. The deprotonated aqueous As(III) on the surface of MRGO-FMBO transferred electrons to Mn(IV), and the formed As(V) oxyanions were bound to ferric oxide as inner-sphere complexes by coordinating their "-OH" groups with Mn(IV) oxides at the surface of MRGO-FMBO. This work could provide new insights into high-performance removal of As(III) in aquifers.

Pressure-Suppressed Carrier Trapping Leads to Enhanced Emission in Two-Dimensional Perovskite (HA)2 (GA)Pb2 I7.

A remarkable PL enhancement by 12 fold is achieved using pressure to modulate the structure of a recently developed 2D perovskite (HA)2 (GA)Pb2 I7 (HA=n-hexylammonium, GA=guanidinium). This structure features a previously unattainable, extremely large cage. In situ structural, spectroscopic, and theoretical analyses reveal that lattice compression under a mild pressure within 1.6 GPa considerably suppresses the carrier trapping, leading to significantly enhanced emission. Further pressurization induces a non-luminescent amorphous yellow phase, which is retained and exhibits a continuously increasing band gap during decompression. When the pressure is released to 1.5 GPa, emission can be triggered by above-band gap laser irradiation, accompanied by a color change from yellow to orange. The obtained orange phase could be retained at ambient conditions and exhibits two-fold higher PL emission compared with the pristine (HA)2 (GA)Pb2 I7 .

Pressure-Driven Reversible Switching between n- and p-Type Conduction in Chalcopyrite CuFeS2.

Temperature-dependent switching between p- and n-type conduction is a newly observed phenomenon in very few Ag-based semiconductors, which may promote fascinating applications in modern electronics. Pressure, as an efficient external stimulus that has driven collective phenomena such as spin-crossover and Mott transition, is also expected to initialize a conduction-type switching in transition metal-based semiconductors. Herein, we report the observation of a pressure-driven dramatic switching between p- and n-type conduction in chalcopyrite CuFeS2 associated with a structural phase transition. Under compression around 8 GPa, CuFeS2 undergoes a phase transition with symmetry breakdown from space group I-42 d to space group I-4 accompanying with a remarkable volume shrinkage of the FeS4 tetrahedra. A high-to-low spin-crossover of Fe2+ ( S = 2 to S = 0) is manifested along with this phase transition. Instead of pressure-driven metallization, a surprising semiconductor-to-semiconductor transition is observed associated with the structural and electronic transformations. Significantly, both photocurrent and Hall coefficient measurements confirm that CuFeS2 undergoes a reversible pressure-driven p- n conduction type switching accompanying with the structural phase transition. The absence of cationic charge transfer between copper and iron during the phase transition is confirmed by both X-ray absorption near-edge spectra (Cu/Fe, K-edge) and total-fluorescence-yield X-ray absorption spectra (Fe, K-edge) results, and the valence distribution maintains Cu2+Fe2+S2 in the high-pressure phase. The observation of an abrupt pressure-driven p- n conduction type switching in a transition metal-based semiconductor paves the way to novel pressure-responsive switching devices.

Revealing the Unusual Rigid Boron Chain Substructure in Hard and Superconductive Tantalum Monoboride.

Poor electrical conductivity severely limits the diverse applications of high hardness materials in situations where electrical conductivities are highly desired. A "covalent metal" TaB with metallic electrical conductivity and high hardness has been fabricated by a high pressure and high temperature method. The bulk modulus, 302.0(4.9) GPa, and Vickers hardness, 21.3 GPa, approaches and even exceeds that of traditional insulating hard materials. Meanwhile, temperature-dependent electrical resistivity measurements show that TaB possesses metallic conductivity that rivals some widely-used conductors, and it will transform into a superconductor at Tc =7.8 K. Contrary to common understanding, the hardness of TaB is higher than that of TaB2 , which indicates that low boron concentration borides could be mechanically better than the higher boron concentration counterparts. Compression behavior and first principles calculations denote that the high hardness is associated with the ultra-rigid covalent boron chain substructure. The hardness of TaB with different topologies of boron substructure shows that besides incorporating higher boron content, manipulating light element backbone configurations is also critical for higher hardness amongst transition metal borides with identical boron content.

Structurally Stable, Antifouling, and Easily Renewable Reduced Graphene Oxide Membrane with a Carbon Nanotube Protective Layer.

The excellent permeability and selectivity of reduced graphene oxide (rGO) membranes have been demonstrated both theoretically and experimentally; however, strategies for the fabrication of highly stable, antifouling rGO membranes with facile recovery after fouling have rarely been investigated. In this work, we report a structurally durable rGO-based hollow fiber membrane that allows high-pressure (at least 1 bar) back-flushing. This is achieved by sandwiching the rGO layer between a carbon nanotube (CNT) protective layer and a polyacrylonitrile (PAN) support. The CNT layer could also function as a prefiltration and pre-adsorption microsystem and endow a higher resistance against fouling. This is experimentally confirmed by the much higher normalized permeance (0.82-0.92) of the CNT/rGO/PAN membranes than the simple rGO/PAN membranes (0.42-0.53) under the same operating conditions. Additionally, under a low cathode potential (0.9 V), the membrane could easily be renewed after fouling by simple back-flushing with a flux recovery ratio of ∼96%. An investigation of the mechanism indicates that electrostatic repulsive forces promote the desorption of charged organic foulants (e.g., humic acid and dyes) from the rGO and CNT layers, and they can subsequently be removed from the membrane with water.

The antagonistic effect of tamoxifen against d-galactosamine/lipopolysaccharide-induced acute liver failure is associated with reactivation of hepatic nuclear factor-κB.

Context: Tamoxifen (TAM) ameliorates D-galactosamine/lipopolysaccharide (Gal/LPS)-induced acute liver failure (ALF) through its antioxidative effect; thus, this study was designed to determine whether the effectiveness of TAM is related to nuclear factor-κB (NF-κB) reactivation. Materials and methods: Experimental mice were injected with TAM once daily for 3 consecutive days intraperitoneally (i.p). Twelve hours after pretreatment, Gal/LPS was given to mice (i.p) for ALF induction. In the positive control group, N-acetylcysteine (NAC) was administered immediately after ALF establishment. Except for survival observation, other animals were sacrificed 7 h after Gal/LPS treatment. Survival and hepatic failure were evaluated. For the oxidation assessment, the reduced/oxidized glutathione (GSH/GSSG) ratio and hepatic superoxide dismutase (SOD) activity were analyzed using both colorimetry and Western blotting. Lastly, hepatic NF-κB activation was measured through Western blot analysis of p65 and IκBα. Results: The results indicated that pretreatment with TAM dramatically attenuated Gal/LPS-induced ALF, as demonstrated by improved survival (70%), decreased transaminase levels, and reversed histopathological manifestation. In addition, the hepatic GSH/GSSG ratio and SOD activity were decreased in the ALF model. However, to some degree, TAM and NAC effectively prevented this undesirable phenomenon in contrast to the ALF model. Western blotting revealed that compared with mice in the ALF model group, mice treated with TAM or NAC showed reactivation of hepatic NF-κB. Conclusions: Taking the results together with those of other studies, we conclude that TAM may attenuate Gal/LPS-induced ALF by antagonizing oxidative stress through NF-κB reactivation.

Refining Inaccurate Transmitter and Receiver Positions Using Calibration Targets for Target Localization in Multi-Static Passive Radar.

Transmitter and receiver position errors have been known to significantly deteriorate target localization accuracy in a multi-static passive radar (MPR) system. This paper explores the use of calibration targets, whose positions are known to the MPR system, to counter the loss in target localization accuracy arising from transmitter/receiver position errors. This paper firstly evaluates the Cramér-Rao lower bound (CRLB) for bistatic range (BR)-based target localization with calibration targets, which analytically indicates the potential of calibration targets in enhancing localization accuracy. After that, this paper proposes a novel closed-form solution, which includes two steps: calibration step and localization step. Firstly, the calibration step is devoted to refine the inaccurate transmitter and receiver locations using the BR measurements from the calibration targets, and then in the calibration step, the target localization can be accurately achieved by using the refined transmitter/receiver positions and the BR measurements from the unknown target. Theoretical analysis and simulation results indicate that the proposed method can attain the CRLB at moderate measurement noise level, and exhibits the superiority of localization accuracy over existing algorithms.