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The optimization design of micro-structure and composition is an important strategy to obtain high-performance metal-based electromagnetic (EM) wave absorption materials. In this work, ZnO/FeNi composites derived from ZnFeNi layered double hydroxides are prepared by a one-step hydrothermal method and subsequent pyrolysis process, and can be employed as an effective alternative for high-performance EM wave absorber. A series of ZnO/FeNi composites with different structures are obtained by varying the molar ratios of Zn2+ /Fe3+ /Ni2+ , and the ZnO/FeNi composites with a Zn2+ /Fe3+ /Ni2+ molar ratio of 6:1:3 show a hierarchical flower-like structure. Owing to the strong synergistic loss mechanism of dielectric-magnetic components and favorable structural features, this hierarchical flower-like ZnO/FeNi sample supplies the optimal EM wave absorption performance with the highest reflection loss of -52.08 dB and the widest effective absorption bandwidth of 6.56 GHz. The EM simulation further demonstrates that impedance matching plays a determining role in EM wave absorption performance. This work provides a new way for the fabrication of a high-performance metal-based EM wave absorber.
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Hydrogen solubility and diffusivity are the key features of hydrogen permeable membrane materials. To characterize the hydrogen permeation performance of NbTM (TM = W, Ru) phases, their hydrogen diffusion coefficient and solution coefficient, thermodynamic stability and chemical bonding are studied by a series of first principles calculations. The phonon spectra and elastic constants show that NbTM is dynamically stable. The TM-H chemical bonds have an ionic/covalent mixed character and are stronger than the Nb-H bond. The preferential diffusion paths of H in both Nb16H and Nb15TMH are from a tetrahedral interstitial site (TIS) to another TIS. The TM doping in Nb16H lowers the solubility and energy barrier of H diffusion and enhances the H diffusion coefficient (D), with Nb16RuH exhibiting the highest D value for TIS to TIS diffusion (2.14 × 10-8 m2 s-1) at 600 K. This study shows that alloying and temperature could significantly affect the solubility and diffusivity of hydrogen in Nb. Moreover, TM doping could greatly improve the hydrogen diffusion performance with good control of hydrogen embrittlement.
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To clarify controversial structures and phase stability in the Li-B system, we predicted energetically favorable compounds and crystal structures of the Li-B binary system at ambient pressure, mainly including Li6B5, LiB2, and LiB3, from ab initio evolutionary structure simulations and further investigated physical properties of stable Li-B compounds using first-principles methods. Metallic Li6B5, predicted in our simulations, has trigonal symmetry with space group R32 and contains linear B chains, but its superconducting Tc is low according to the electron-phonon coupling calculations. Orthorhombic LiB2 (Pnma) and tetragonal LiB3 (P4/mbm) are zero-gap semiconductors; LiB2 is a Dirac semimetal, and both LiB2 and LiB3 are promising thermoelectric materials.
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To predict all stable compounds in the Ba-C system, we perform a comprehensive study using first-principles variable-composition evolutionary algorithm USPEX. We find that at 0 K the well-known compound BaC2 is metastable in the whole pressure range 0-40 GPa, while intercalated graphite phase BaC6 is stable at 0-19 GPa. A hitherto unknown layered orthorhombic Pbam phase of BaC has structure consisting of alternating layers of Ba atoms and layers of stoichiometry Ba2C3 containing linear C3 groups and is predicted to be stable in the pressure range 3-32 GPa. From our electron-phonon coupling calculations, the newly found BaC compound is a phonon-mediated superconductor and has a critical superconductivity temperature Tc of 4.32 K at 5 GPa. This compound is dynamically stable at 0 GPa and therefore may be quenchable under normal conditions.
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This study aimed to investigate the roles of lysosome-related genes in BC prognosis and immunity. Transcriptome data from TCGA and MSigDB, along with lysosome-related gene sets, underwent NMF cluster analysis, resulting in two subtypes. Using lasso regression and univariate/multivariate Cox regression analysis, an 11-gene signature was successfully identified and verified. High- and low-risk populations were dominated by HR+ sample types. There were differences in pathway enrichment, immune cell infiltration, and immune scores. Sensitive drugs targeting model genes were screened using GDSC and CCLE. This study constructed a reliable prognostic model with lysosome-related genes, providing valuable insights for BC clinical immunotherapy.
Lysosome-related genes can be used to predict survival outcomes in BRCA patients.Significant differences were showed in the immune status of patient with different prognoses.Immunotherapy may show better therapeutic results in low-risk patients.The most promising targeted drugs in the low-risk group are mainly Lapatinib, Palbociclib and Ribociclib.
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Diborane (B(2)H(6)), a high energy density material, was believed to be stable in a wide P, T interval. A systematic investigation of the B-H system using the ab initio variable-composition evolutionary simulations shows that boron monohydride (BH) is thermodynamically stable and can coexist with solid B, H(2), and B(2)H(6) in a wide pressure range above 50 GPa. B(2)H(6) becomes unstable and decomposes into the Ibam phase of BH and H(2) (C2/c) at 153 GPa. The semiconducting layered Ibam structure of BH at 168 GPa transforms into a metallic phase with space group P6/mmm and a 3D topology with strong B-B and B-H covalent bonds. The Ibam-P6/mmm transformation pathway suggests the possibility of obtaining the metastable Pbcm phase on cold decompression of the P6/mmm phase. The electron-phonon coupling calculations indicate that P6/mmm-BH is a phonon-mediated superconductor with a critical temperature of superconductivity (T(c)) of 14.1-21.4 K at 175 GPa.
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Palladium (Pd) is widely used in catalyst, aerospace, and medical applications, but only 1% of its reserves are found in nature. So, the recovery of Pd(II) is very important. Natural fibers are a good adsorption material, and the abundant functional groups in bamboo shoot shell (BSS) fibers can form interactions with metal particles. However, few studies on Pd(II) adsorption using BSS fibers exist. In the present work, waste bamboo shoot shells were doped with titanium dioxide (TiO2) particles, and the surface activation of BSS-TiO2@CA by citric acid (CA) was carried out to prepare an efficient and recyclable adsorbent BSS-TiO2@CA for the adsorption of Pd(II). The adsorption performance, adsorption mechanism, and regeneration performance of BSS-TiO2@CA on Pd(II) were systematically analyzed by continuous adsorption experiments, characterization, and response surface method. It was found that the surface-activated waste bamboo shoot shells had an outstanding adsorption capacity of Pd(II), and the maximum adsorption rate of BSS-TiO2@CA reached 85% with a maximum adsorption capacity (Qm) of 175.74 mg/g. The functionalized use of waste bamboo shoot shells provides a new idea for the development of sustainable, cost-effective, and environmentally friendly adsorbents.
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Paládio , Poluentes Químicos da Água , Adsorção , Biomassa , TitânioRESUMO
A novel 3D porous metal-organic framework with 1D polarized channels was synthesized, and its adsorption properties for gas separation and chemical sensing were studied. The framework shows a preferential adsorption of CO(2) over N(2) with a selectivity of 22:1. It also exhibits a very good sensitivity to water with respect to most of the organic solvents in view of chemical sensing applications.
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A highly efficient MgBi2O6 (MBO)/TiO2 heterostructured photocatalyst for the evolution of H2 was successfully prepared using a one-step hydrothermal method. The phase structure, microstructure and optical properties of the MBO/TiO2 composites were investigated by various experimental techniques. A series of H2 production experiments were performed under visible light. The measured results indicated that the nanostructured MBO/TiO2 composite, with a stoichiometric molar ratio of MBO:TiO2 = 0.2%, displayed the best H2 production rate of 3413 µmol h-1 g-1. The excellent photocatalytic performance of the obtained composite material was due to the heterojunction formed between MBO and TiO2, which reduced the charge transfer resistance and accelerated the separation efficiency of the photogenerated electron-hole pairs. The reaction mechanism was also discussed in detail.
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Background: Pertuzumab plus trastuzumab combined with chemotherapy has become a standard neoadjuvant therapy option for patients with high-risk human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC). There is still not enough evidence for the efficacy and safety of neoadjuvant pertuzumab and trastuzumab plus chemotherapy in HER2-positive BC patients in China, both in clinical trials and real-world settings. This study aimed to assess the efficacy and safety of neoadjuvant pertuzumab plus trastuzumab in combination with chemotherapy in Chinese patients with HER2-positive BC in real-world clinical application. Methods: We retrospectively collected the data from the electronic medical records of HER2-positive patients treated with neoadjuvant trastuzumab and pertuzumab plus chemotherapy from December 2018 to May 2021 at 21 hospitals located in Hunan Province, China, including age, American Joint Committee on Cancer (AJCC) stage, clinical tumor size, clinical lymph node status, pathological characteristics (before neoadjuvant systemic therapy), treatment approach, adverse events to neoadjuvant therapy, and achievement of pathological complete response (pCR). The primary endpoint was the total rate of pCR, and the secondary endpoints were the rate of pCR of each subgroup and the safety of dual anti-HER2 therapy. Results: A total of 188 patients met the inclusion criteria and were included in the analysis. Of the 188 patients, 119 (63.3%) were diagnosed at stage II and 64 (34.0%) at stage III; 163 (86.7%) were cT2-3; 149 patients (79.3%) were ≥ cN1; 84 patients (44.7%) were hormone receptor (HR)-positive. pCR was observed in 88 of 188 patients (46.8%). The pCR rate of HR-negative patients (54.8%) was higher (P=0.014) than that of HR-positive patients (36.9%). Patients with Ki-67 <15% achieved a higher (P=0.033) pCR rate (68.2%) than those with Ki-67 ≥15% (44.0%). Anemia was the most common adverse event (63.4%), and the most common grade 3-4 adverse event was nausea and vomiting (8.5%). Conclusions: Our study confirmed the benefit of neoadjuvant pertuzumab plus trastuzumab in combination with chemotherapy on pCR with a tolerable safety profile in routine clinical practice in Chinese patients with HER2-positive BC. HR-negativity and Ki-67 <15% were associated with pCR in these patients.
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We reported the magnetic, dielectric and magnetoelectric properties of NdCrO3 polycrystalline ceramics. Magnetization curves revealed two magnetic transitions at 227 K and 38 K, which corresponded to Cr3+ canted antiferromagnetic ordering and Cr3+ spin reorientation phase transition, respectively. At 11.5 K, a Schottky-type anomaly was observed, caused by Nd3+ ground doublet Zeeman splitting. High-temperature dielectric relaxation exhibited a type of thermally activated relaxation process, which mainly resulted from the Maxwell-Wagner effect. The spin-reorientation of Cr3+ ions and the Nd3+ ground doublet splitting were observed to be accompanied by an electric polarization. The polarization could be induced by the presence of the antiferromagnetic-type domain walls, which led to spatial inversion symmetry breaking.
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High temperature dielectric relaxation behaviors of single phase Mn3O4 polycrystalline ceramics prepared by spark plasma sintering technology have been studied. Two dielectric relaxations were observed in the temperature range of 200 K-330 K and in the frequency range of 20 Hz-10 MHz. The lower temperature relaxation is a type of thermally activated relaxation process, which mainly results from the hopping of oxygen vacancies based on the activation energy analysis. There is another abnormal dielectric phenomenon that is different from the conventional thermally activated behavior and is related to a positive temperature coefficient of resistance (PTCR) effect in the temperature region. In line with the impedance analyses, we distinguished the contributions of grains and grain boundaries. A comparison of the frequency-dependent spectra of the imaginary impedance with imaginary electric modulus suggests that both the long range conduction and the localized conduction are responsible for the dielectric relaxations in the Mn3O4 polycrystalline samples.
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Antimony sulfide (Sb2S3) with a high theoretical capacity is considered as a promising candidate for Na-ion batteries (NIBs) and K-ion batteries (KIBs). However, its poor electrochemical activity and structural stability are the main issues to be solved. Herein, amorphous Sb2S3 nanospheres/carbon nanotube (Sb2S3/CNT) nanocomposites are successfully synthesized via one step self-assembly method. In-situ growth of amorphous Sb2S3 nanospheres on the CNTs is confirmed by X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. The amorphous Sb2S3/CNT nanocomposites as an anode for NIBs exhibit excellent electrochemical performance, delivering a high charge capacity of 870 mA h g-1 at 100 mA g-1, with an initial coulomb efficiency of 77.8%. Even at 3000 mA g-1, a charge capacity of 474 mA h g-1 can be achieved. As an anode for KIBs, the amorphous Sb2S3/CNT nanocomposites also demonstrate a high charge capacity of 451 mA h g-1 at 25 mA g-1. The remarkable performance of the amorphous Sb2S3/CNT nanocomposites is attributed to the synergic effects of the amorphous Sb2S3 nanospheres and 3D porous conductive network constructed by the CNTs.
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First-principles calculations and the method of climbing-image nudged elastic band were used to investigate the effects of Mo alloying on the structural stability, mechanical properties, and hydrogen-diffusion behavior in the Nb16H phase. The Nb12Mo4H phase (26.5 at% Mo) was found to be the most thermodynamically stable structure, with a low ΔH f value (-0.26 eV) and high elastic modulus. Calculations revealed that the tetrahedral interstitial site (TIS) was the predominant location of H in both Nb16H and Nb12Mo4H phases. The calculated H-diffusion energy barrier and the diffusion coefficient of the Nb12Mo4H phase were 0.153 eV and 5.65 × 10-6 cm2 s-1 (300 K), respectively, which suggest that the addition of Mo would lead to a lower energy barrier and high diffusion coefficients for the Nb16H phase, thus improving the hydrogen-permeation properties of Nb metal.
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Changes in the stability, hydrogen diffusion, and mechanical properties of the NbH phases from Ni-doping was studied by using first-principles methods. The calculation results reveal that the single H atom adsorption is energetically favorable at the tetrahedral interstitial site (TIS) and octahedral interstitial site (OIS). The preferred path of H diffusion is TIS-to-TIS, followed by TIS-to-OIS in both Nb16H and Nb15NiH. Ni-doping in the Nb15NiH alloy lowers the energy barrier of H diffusion, enhances the H-diffusion coefficient (D) and mechanical properties of the Nb16H phase. The value of D increases with increasing temperature, and this trend due to Ni doping clearly becomes weaker at higher temperatures. At the typical operating temperature of 400 K, the D value of Nb15NiH (TIS) is about 1.90 × 10-8 m2/s, which is about 80 times higher than that of Nb16H (TIS) (2.15 × 10-10 m2/s). Our calculations indicated that Ni-doping can greatly improve the diffusion of H in Nb.
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Nitrogen hydrides, e.g., ammonia (NH3), hydrazine (N2H4) and hydrazoic acid (HN3), are compounds of great fundamental and applied importance. Their high-pressure behavior is important because of their abundance in giant planets and because of the hopes of discovering high-energy-density materials. Here, we have performed a systematic investigation on the structural stability of N-H system in a pressure range up to 800 GPa through evolutionary structure prediction. Surprisingly, we found that high pressure stabilizes a series of previously unreported compounds with peculiar structural and electronic properties, such as the N4H, N3H, N2H and NH phases composed of nitrogen backbones, the N9H4 phase containing two-dimensional metallic nitrogen planes and novel N8H, NH2, N3H7, NH4 and NH5 molecular phases. Another surprise is that NH3 becomes thermodynamically unstable above ~460 GPa. We found that high-pressure chemistry of hydronitrogens is much more diverse than hydrocarbon chemistry at normal conditions, leading to expectations that N-H-O and N-H-O-S systems under pressure are likely to possess richer chemistry than the known organic chemistry. This, in turn, opens a possibility of nitrogen-based life at high pressure. The predicted phase diagram of the N-H system also provides a reference for synthesis of high-energy-density materials.
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The interaction of [BH(x)]- and [NH(x)]-containing species gives rise to molecular hydrogen and the establishment of the B-N bond. Up to now, metal amides and ammonia are the commonly used [NH(x)] sources. Herein, urea, an organic carbonyl diamide, was used to react with Ca(BH4)2. A new type of complex hydride Ca(BH4)2·4CO(NH2)2 was synthesized with release of ca. 5.2 wt% hydrogen below 250 °C.
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Gold nanoparticles (GNPs) assembled polyaniline nanospheres (PANS) composite were prepared by noncovalent strategy. Cytochrome c (Cyt c) was electrostatically adsorbed on the GNPs/PANS modified electrode. The direct electron transfer (DET) between Cyt c and GNPs/PANS modified electrode was investigated. Cyt c shows a couple of quasi-reversible and well-defined cyclic voltammetry (CV) peaks with a formal potential (E(0')) of -0.27 V (versus Ag/AgCl) in pH 7.0 phosphate buffer solution (PBS). The Cyt c/GNPs/PANS modified electrode gives an improved electrocatalytic activity toward the reduction of hydrogen peroxide (H2O2). The catalysis currents increase linearly to the H2O2 concentration in a wide range of 0.01-2.4 mM with a correlation coefficient 0.998. After immobilized glucose oxidase (GOD) on the Cyt c/GNPs/PANS modified electrode by Nafion polymer, a bienzymatic glucose biosensor was further prepared for sensitive detection of glucose. The amperometric detection of glucose was assayed by potentiostating the bienzymatic electrode at -0.2 V versus Ag/AgCl to reduce the enzymatically produced H2O2 with minimal interference from the coexisting electroactive compounds. The proposed glucose biosensor exhibits good response performance to glucose with a wide linear range from 0.01 to 3.2mM with a correlation coefficient of 0.997. The electrode has high sensitivity of 63.1 µA mM(-1)cm(-2) and a detection limit 0.01 mM at the signal-to-noise ratio of 3. Moreover, the glucose biosensor possesses good stability and reproducibility.
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Compostos de Anilina/química , Técnicas Biossensoriais , Citocromos c/metabolismo , Técnicas Eletroquímicas/métodos , Glucose/análise , Ouro/química , Nanopartículas Metálicas , Animais , Cavalos , Microscopia Eletrônica de TransmissãoRESUMO
A nanoscale aluminium-based metal organic framework (NMOF) with high thermal stability has been synthesized, which shows high H(2) and CO(2) uptake capacities and an excellent selectivity for CO(2) over N(2) and O(2).
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The structure transition of flexible MOF (MIL-53) can be adjusted by confinement of BNH(x) into MIL-53 channels. Hydrogen and carbon dioxide adsorption properties are also improved by incorporating BNH(x). At 77 K and 1 atm pressure hydrogen storage capacity can reach 2.0 wt% and CO(2) adsorption capacity is 4.5 mmol g(-1) at 273 K 1 atm.