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Here, we present a novel, to the best of our knowledge, optical edge detection scheme that can be operated in both linear and circular polarization modes, leveraging an optical spatial differentiator constructed by quarter-wave Pancharatnam-Berry (P-B) phase gradient element. After explaining the theoretical mechanism, we utilize a quarter-wave P-B phase liquid crystal polarization grating to validate the dual-polarization optical edge detection capability. We demonstrate that the orientation of linear polarization and the spin of circular polarization dictate the transition between edge and bright-field images. Besides, the linear and circular polarization modes exhibit broadband and monochromatic responsive properties, respectively. This mechanism, dependent on wavelength and polarization, holds promise for applications in color image processing, chiral sensing imaging, and polarization-entangled quantum imaging.
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The dopamine transporter has a crucial role in regulation of dopaminergic neurotransmission by uptake of dopamine into neurons and contributes to the abuse potential of psychomotor stimulants1-3. Despite decades of study, the structure, substrate binding, conformational transitions and drug-binding poses of human dopamine transporter remain unknown. Here we report structures of the human dopamine transporter in its apo state, and in complex with the substrate dopamine, the attention deficit hyperactivity disorder drug methylphenidate, and the dopamine-uptake inhibitors GBR12909 and benztropine. The dopamine-bound structure in the occluded state precisely illustrates the binding position of dopamine and associated ions. The structures bound to drugs are captured in outward-facing or inward-facing states, illuminating distinct binding modes and conformational transitions during substrate transport. Unlike the outward-facing state, which is stabilized by cocaine, GBR12909 and benztropine stabilize the dopamine transporter in the inward-facing state, revealing previously unseen drug-binding poses and providing insights into how they counteract the effects of cocaine. This study establishes a framework for understanding the functioning of the human dopamine transporter and developing therapeutic interventions for dopamine transporter-related disorders and cocaine addiction.
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Benzotropina , Proteínas da Membrana Plasmática de Transporte de Dopamina , Inibidores da Captação de Dopamina , Dopamina , Humanos , Apoproteínas/metabolismo , Apoproteínas/química , Transtorno do Deficit de Atenção com Hiperatividade/tratamento farmacológico , Benzotropina/metabolismo , Benzotropina/farmacologia , Sítios de Ligação , Cocaína/farmacologia , Cocaína/metabolismo , Transtornos Relacionados ao Uso de Cocaína/tratamento farmacológico , Dopamina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Dopamina/antagonistas & inibidores , Proteínas da Membrana Plasmática de Transporte de Dopamina/química , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Inibidores da Captação de Dopamina/metabolismo , Inibidores da Captação de Dopamina/farmacologia , Metilfenidato/metabolismo , Metilfenidato/farmacologia , Modelos Moleculares , Piperazinas/metabolismo , Piperazinas/farmacologia , Ligação Proteica , Conformação ProteicaRESUMO
An optical spatial differentiator based on the photonic spin Hall effect (PSHE) with high tunability is presented. By utilizing the characteristics of ultra-high order modes in the symmetrical metal cladding waveguide, the Fresnel reflection coefficient spectrum exhibits a narrow peak width and low trough at the resonant incident angles, resulting in high sensitivity to changes in the incident angle-induced spatial shift caused by the PSHE (the highest ∂(|r s/r p|)/∂ θ value can reach 107). After polarization transformation and extinction, the output field demonstrates differential operation with respect to the input field. When applied to edge detection, our differentiator can achieve tunable resolution edge images by adjusting the incident angle. Our proposed edge detection scheme has potential applications for cellular and molecular imaging through two-dimensional extension via the target rotation.
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Neurodegenerative diseases are debilitating nervous system disorders attributed to various conditions such as body aging, gene mutations, genetic factors, and immune system disorders. Prominent neurodegenerative diseases include Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and multiple sclerosis. Insulin resistance refers to the inability of the peripheral and central tissues of the body to respond to insulin and effectively regulate blood sugar levels. Insulin resistance has been observed in various neurodegenerative diseases and has been suggested to induce the occurrence, development, and exacerbation of neurodegenerative diseases. Furthermore, an increasing number of studies have suggested that reversing insulin resistance may be a critical intervention for the treatment of neurodegenerative diseases. Among the numerous measures available to improve insulin sensitivity, exercise is a widely accepted strategy due to its convenience, affordability, and significant impact on increasing insulin sensitivity. This review examines the association between neurodegenerative diseases and insulin resistance and highlights the molecular mechanisms by which exercise can reverse insulin resistance under these conditions. The focus was on regulating insulin resistance through exercise and providing practical ideas and suggestions for future research focused on exercise-induced insulin sensitivity in the context of neurodegenerative diseases.
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Lung cancer is a malignant tumor with high mortality and drug resistance. Therefore, it is urgent to explore natural and nontoxic drugs to treat lung cancer. In this study, the natural active ingredient AANL extracted from Agrocybe aegirita was used to modify nanoselenium by an oxidation-reduction method. Transmission electron microscope detection and infrared spectroscopy showed that a novel selenium nanocomposite named AANL-SeNPs was successfully prepared. The results of nanoscale characterization showed that AANL-SeNPs had good stability and uniform dispersion in aqueous solution by zeta potential and spectrum analysis. At the cellular level, we found that AANL-SeNPs significantly inhibited the cell viability of lung cancer cells, and the cell inhibition rate of 60 nM AANL-SeNPs was 39 % in H157 cells, 67 % in H147 cells, and 62 % in A549 cells. The IC50 value of AANL-SeNPs was 51.85 nM in A549 cells and 81.57 nM in H157 cells. Moreover, AANL-SeNPs could inhibit the cell proliferation and migration, and enhance the sensitivity of lung cancer cells to osimertinib and has no toxic to normal cells. In vivo, AANL-SeNPs significantly slowed tumor growth in tumor-bearing mice by establishing a subcutaneous transplantation tumor model for lung cancer, and the tumor size was smaller and was reduced about 79 % in 2 mg/kg AANL-SeNPs group compared with PBS group. Mechanistically, a total of 38 differentially expressed proteins were identified by data-independent acquisition mass spectrometry. A significantly upregulated protein, CDC-like kinase 2 (CLK2), was screened and validated for further analysis, which showed that the expression levels of CLK2 were increased in H157 and H1437 cells after AANL-SeNPs treatment. The results obtained in this study suggest that a novel selenium nanocomposite AANL-SeNPs, which inhibits lung cancer by upregulating the expression of CLK2.
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Antineoplásicos , Proliferação de Células , Neoplasias Pulmonares , Nanocompostos , Proteínas Tirosina Quinases , Selênio , Regulação para Cima , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Nanocompostos/química , Proliferação de Células/efeitos dos fármacos , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Animais , Selênio/química , Selênio/farmacologia , Camundongos , Regulação para Cima/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Relação Dose-Resposta a Droga , Estrutura Molecular , Relação Estrutura-Atividade , Sobrevivência Celular/efeitos dos fármacos , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/patologia , Neoplasias Experimentais/metabolismo , Linhagem Celular Tumoral , Camundongos Endogâmicos BALB C , Camundongos NusRESUMO
The voltage-gated calcium channel CaV1.2 is essential for cardiac and vessel smooth muscle contractility and brain function. Accumulating evidence demonstrates that malfunctions of CaV1.2 are involved in brain and heart diseases. Pharmacological inhibition of CaV1.2 is therefore of therapeutic value. Here, we report cryo-EM structures of CaV1.2 in the absence or presence of the antirheumatic drug tetrandrine or antihypertensive drug benidipine. Tetrandrine acts as a pore blocker in a pocket composed of S6II, S6III, and S6IV helices and forms extensive hydrophobic interactions with CaV1.2. Our structure elucidates that benidipine is located in the DIII-DIV fenestration site. Its hydrophobic sidechain, phenylpiperidine, is positioned at the exterior of the pore domain and cradled within a hydrophobic pocket formed by S5DIII, S6DIII, and S6DIV helices, providing additional interactions to exert inhibitory effects on both L-type and T-type voltage gated calcium channels. These findings provide the structural foundation for the rational design and optimization of therapeutic inhibitors of voltage-gated calcium channels.
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Canais de Cálcio Tipo L , Canais de Cálcio Tipo L/metabolismo , Estrutura Secundária de ProteínaRESUMO
Objective: This study aimed to evaluate the therapeutic efficacy and safety of Dan'e Fukang soft extracts in moderate ovarian hyperstimulation syndrome (OHSS) for the simultaneous treatment of blood and fluid, guided by the traditional Chinese medicine principle of "triple prevention". Methods: This study conducted a retrospective analysis of clinical data from outpatients who underwent in vitro fertilization (IVF)/intracytoplasmic sperm injection embryo transfer (ICSI-ET). A total of 2245 cases were included and divided into a treatment group (1002 cases) and a control group (1243 cases). Patients in the treatment group were administered Dan'e Fukang soft extracts orally in addition to conventional Western medicine. Comparative assessments were made between the two groups on pelvic ascites volume, maximum ovary diameter, dysmenorrhea incidence post-oocyte retrieval, and safety indicators. Results: There were no statistically significant differences between the treatment group and the control group in terms of general characteristics or the levels of follicle-stimulating hormone (FSH), luteotropic hormone (LH), estradiol (E2), or progesterone (P) at the time of gonadotropin (Gn) initiation. The groups did not differ significantly when we compared the levels of LH, E2, or P on the day of human chorionic gonadotropin (hCG) injection and during ovarian hyperstimulation protocols (P > 0.05 for all indicators). The differences in the volume of pelvic ascites, the maximum ovarian diameter, and the incidence of dysmenorrhea after oocyte retrieval were statistically significant between the treatment group and the control group (P < 0.05 in both). There were no instances of adverse reactions in either group. Conclusion: Based on the traditional Chinese medicine principle of "triple prevention", the use of Dan'e Fukang soft extracts for the simultaneous treatment of blood and fluid in moderate OHSS significantly improved the absorption of pelvic ascites, promoted ovarian recovery, and reduced the incidence of dysmenorrhea after oocyte retrieval.
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Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the onset of symptoms, typically occurring later in life, and significant deficits in cognitive functions including learning, memory, speech, and behavior. Ongoing research endeavors seek to explore methods for preventing and treating AD, as well as delving into the molecular mechanisms underlying existing and novel therapeutic approaches encompassing exercise, diet, and drug regimens for individuals with AD or those at risk of developing AD. Among these interventions, dietary interventions have garnered increasing attention due to their potential in addressing the disease. Eating is among the most fundamental of human daily activities, and controlled dietary practices, such as fasting, have gained prominence as essential clinical methods for disease prevention and treatment. Research findings indicate that fasting holds promise in effectively alleviating and improving the cognitive decline associated with age or as consequence of disease. The clinical efficacy of fasting in addressing AD and related disorders might be grounded in its influence on various molecular mechanisms, including neuroinflammation, glial cell activation, insulin resistance, autophagy regulation, nerve regeneration, the gut microbiome, and accumulations of amyloid-ß and tau proteins. The present study reviews possible molecular mechanisms underpinning the therapeutic effects of fasting in patients with AD, as well as in models of the disorder, to establish a theoretical basis for using fasting as a viable approach to treat AD.
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Doença de Alzheimer , Humanos , Animais , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/metabolismo , Jejum , Proteínas tau , Aprendizagem , Modelos Animais de DoençasRESUMO
Chiral transition metal oxides (TMOs) are in the forefront of research as potential active materials in various optoelectronic applications. However, the nonlinear optical (NLO) properties of the chiral TMOs have not been fully understood. Here, several kinds of copper oxide nanosheets capped with different chiral amino acids are synthesized. Notably, we investigate the NLO activities of these materials, including broadband second harmonic generation and transformation of nonlinear optical properties from saturable absorption to reverse saturable absorption. This work will broaden the use of chiral TMO materials in nonlinear photonic devices.
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Background: Unilateral twin ectopic pregnancy is extremely rare in natural pregnancy, with an incidence rate of only 1 in 200,000-2,500,000, represents a major health risk for reproductive-aged women, leading to even life-threatening complications. There is a lack of data on the prevalence of this rare disease after in-vitro fertilization-embryo transfer (IVF-ET) cycles. Case Report: We present a case of a 51-year-old woman with rare unilateral twin ectopic pregnancy after frozen embryo transfer treated with bilateral salpingectomy, followed by a review of the literature. Conclusion: Twin ectopic pregnancy is a very rare type of pregnancy that requires a high index of suspicion to diagnose and treat early to prevent complications and maternal death.
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Background: Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a life-threatening infectious disease that has become a global pandemic. Objective: This study aimed to explore the effects of SARS-CoV-2 inactivated vaccine on the outcome of frozen embryo transfer (FET). Methods: We grouped patients who underwent FET between August 2021 and March 2022 based on their vaccination status, number of doses, and the interval between the last dose and the FET, and then compared the differences in pregnancy outcomes among the groups. Results: There were 1084 vaccinated patients and 1228 non-vaccinated ones. There were significant differences in the live birth rate between the vaccination and non-vaccination groups (16.61% vs 28.26%), among the one-dose, two-dose, and three-dose groups (22.28% vs 19.51% vs 7.27%), and among the groups with interval ≤ 1 month, 1-2 months, and ≥ 2 months (38.38% vs 27.27% vs 12.03%). There were significant differences in the persistent pregnancy rate between the vaccination and non-vaccination groups (22.88% vs 14.09%), among the one-dose, two-dose, and three-dose groups (14.51% vs 23.80% vs 38.18%), and among the groups with interval ≤ 1 month, 1-2 months, and ≥ 2 months (1.01% vs 8.44% vs 28.16%). There were significant differences in the neonatal weight between the vaccination and non-vaccination groups [3805.50 (3746.00-3863.50) vs 2970.00 (2500.00-3400.00)]. There were significant differences in the premature birth rate among the one-dose, two-dose, and three-dose groups (23.26% vs 34.59% vs 100.00%), and among the groups with interval ≤ 1 month, 1-2 months, and ≥ 2 months (15.79% vs 21.43% vs 37.00%). Conclusion: Pregnancy outcomes were not affected by taking the SARS-CoV-2 inactivated vaccine before FET, the number of doses, and the interval between doses. These findings provide evidence supporting the safety of administering the SARS-CoV-2 inactivated vaccine during pregnancy, which can be used as a guide for vaccinating patients undergoing ART.
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BACKGROUND: Neurotransmitter release depends on the fusion of synaptic vesicles with the presynaptic membrane and is mainly mediated by SNARE complex assembly. During the transition of Munc18-1/Syntaxin-1 to the SNARE complex, the opening of the Syntaxin-1 linker region catalyzed by Munc13-1 leads to the extension of the domain 3a hinge loop, which enables domain 3a to bind SNARE motifs in Synaptobrevin-2 and Syntaxin-1 and template the SNARE complex assembly. However, the exact mechanism of domain 3a extension remains elusive. RESULTS: Here, we characterized residues on the domain 3a hinge loop that are crucial for the extension of domain 3a by using biophysical and biochemical approaches and electrophysiological recordings. We showed that the mutation of residues T323/M324/R325 disrupted Munc13-1-mediated SNARE complex assembly and membrane fusion starting from Munc18-1/Syntaxin-1 in vitro and caused severe defects in the synaptic exocytosis of mouse cortex neurons in vivo. Moreover, the mutation had no effect on the binding of Synaptobrevin-2 to isolated Munc18-1 or the conformational change of the Syntaxin-1 linker region catalyzed by the Munc13-1 MUN domain. However, the extension of the domain 3a hinge loop in Munc18-1/Syntaxin-1 was completely disrupted by the mutation, leading to the failure of Synaptobrevin-2 binding to Munc18-1/Syntaxin-1. CONCLUSIONS: Together with previous results, our data further support the model that the template function of Munc18-1 in SNARE complex assembly requires the extension of domain 3a, and particular residues in the domain 3a hinge loop are crucial for the autoinhibitory release of domain 3a after the MUN domain opens the Syntaxin-1 linker region.
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Proteínas do Tecido Nervoso , Proteína 2 Associada à Membrana da Vesícula , Camundongos , Animais , Proteínas do Tecido Nervoso/genética , Proteína 2 Associada à Membrana da Vesícula/genética , Proteína 2 Associada à Membrana da Vesícula/metabolismo , Sintaxina 1/genética , Sintaxina 1/química , Sintaxina 1/metabolismo , Proteínas Qa-SNARE/genética , Proteínas Qa-SNARE/metabolismo , Proteínas SNARE/metabolismo , Ligação ProteicaRESUMO
The pathogenesis mechanism of lung cancer is very complex, with high incidence and mortality. Serpin family A member 3 (SERPINA3) expression levels were reduced in the sera of patients with lung cancer and may be a candidate diagnostic and prognostic survival biomarker in lung cancer, as previously reported. However, the detailed biological functions of SERPINA3 in the pathogenesis of lung cancer remain unknown. In the present study, it was aimed to explore the effects of SERPINA3 on the occurrence of lung cancer. SERPINA3 expression was assessed using bioinformatics database analysis and experimental detection. Then, the biological effects of SERPINA3 were investigated in a cell culture system and a xenograft model of human lung cancer. The potential regulatory mechanism of SERPINA3 in lung cancer was explored by dataindependent acquisition mass spectrometry (DIAMS) detection and further validated by western blotting (WB). The results indicated that SERPINA3 expression levels were significantly downregulated in lung cancer tissues and cell lines. At the cellular level, it was revealed that overexpressed SERPINA3 inhibited cell growth, proliferation, migration and invasion and promoted the apoptosis of lung cancer cells. Moreover, overexpressed SERPINA3 enhanced the sensitivity of lung cancer cells to osimertinib. In vivo, a xenograft model of human lung cancer was established with BALB/c nude mice. After the injection of A549 cells, the tumor growth of the tumorbearing mice in the SERPINA3overexpressing group increased more slowly, and the tumor volume was smaller than that in the emptyvector group. Mechanistically, a total of 65 differentially expressed proteins were identified. It was found that the speckletype POZ protein (SPOP) was significantly upregulated in SERPINA3overexpressing H157 cells using DIAMS detection and analysis. WB validation showed that SPOP expression increased, and NFkappaB (NFκB) p65 was inhibited in cell lines and tumor tissues of mice when SERPINA3 was overexpressed. The present findings suggest that SERPINA3 is involved in the development of lung cancer and has an antineoplastic role in lung cancer.
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Neoplasias Pulmonares , Serpinas , Humanos , Animais , Camundongos , NF-kappa B/metabolismo , Camundongos Nus , Linhagem Celular Tumoral , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Proliferação de Células , Movimento Celular , Regulação Neoplásica da Expressão Gênica , Serpinas/genética , Serpinas/metabolismoRESUMO
BACKGROUND: Trophoblasts are the most important parts of the placenta in early pregnancy. Trophoblast cell dysfunction can induce embryo implantation insufficiency, thereby resulting in multiple diseases, including recurrent spontaneous abortion (RSA). A previous study indicates higher nerve injury-induced protein 1 (NINJ1) RNA levels in the villi tissues of RSA patients. OBJECTIVE: This study aimed to investigate the effect of NINJ1 on trophoblast behaviors and pregnancy loss. METHODS: Fresh villi tissues were obtained from with RSA patients and patients with artificial selective abortion for personal reasons, and NINJ1 expression in these tissues was detected. Extravillous trophoblast cell line HTR-8/SVneo was transfected with small-interfering RNA targeting NINJ1 or NINJ1 overexpression vector to perform loss-/gain-of-function experiments. Spontaneous abortion (SA) was induced by mating CBA/J females with DBA/2 males and the pregnant females were intraperitoneally injected with adenovirus vector carrying NINJ1 short hairpin RNA. RESULTS: NINJ1 mRNA and protein levels were higher in the villi tissues of RSA patients than those of artificial selective abortion patients. NINJ1 knockdown promoted trophoblast cell proliferation, migration and invasion but inhibited cell apoptosis. Moreover, conditioned medium from NINJ1-depleted trophoblasts promoted the angiogenesis of human umbilical vein endothelial cells. NINJ1 knockdown also promoted activation of the signal transducer and activator of transcription 3 (STAT3) signaling pathway in trophoblasts, and STAT3 inhibitor reversed NINJ1 knockdown-induced effects on trophoblast behaviors. Furthermore, pregnancy loss was attenuated by NINJ1 inhibition. CONCLUSION: NINJ1 contributes to the development of SA and triggers trophoblast cell dysfunction through inhibiting the STAT3 pathway.
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Aborto Habitual , Trofoblastos , Moléculas de Adesão Celular Neuronais/metabolismo , Movimento Celular/genética , Meios de Cultivo Condicionados/metabolismo , Meios de Cultivo Condicionados/farmacologia , Feminino , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Fatores de Crescimento Neural/metabolismo , Fatores de Crescimento Neural/farmacologia , Gravidez , RNA Mensageiro/metabolismo , RNA Interferente Pequeno , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais , Trofoblastos/metabolismoRESUMO
In this study, oxide dispersion-strengthened Cu alloy with a Y2O3 content of 1 wt.% was fabricated through citric acid sol-gel synthesis and spark plasma sintering (SPS). The citric acid sol-gel method provides molecular mixing for the preparation of precursor powders, which produces nanoscale and uniformly distributed Y2O3 particles in an ultrafine-grained Cu matrix. The effects of nanoscale Y2O3 particles on the microstructure, mechanical properties and thermal conductivity of the Cu-1wt.%Y2O3 alloy were investigated. The average grain size of the Cu-1wt.%Y2O3 alloy is 0.42 µm, while the average particle size of Y2O3 is 16.4 nm. The unique microstructure provides excellent mechanical properties with a tensile strength of 572 MPa and a total elongation of 6.4%. After annealing at 800 °C for 1 h, the strength of the alloy does not decrease obviously, showing excellent thermal stability. The thermal conductivity of Cu-1wt.%Y2O3 alloy is about 308 Wm-1K-1 at room temperature and it decreases with increasing temperature. The refined grain size, high strength and excellent thermal stability of Cu-1wt.%Y2O3 alloys can be ascribed to the pinning effects of nanoscale Y2O3 particles dispersed in the Cu matrix. The Cu-Y2O3 alloys with high strength and high thermal conductivity have potential applications in high thermal load components of fusion reactors.
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OBJECTIVE: This study aimed to investigate the duration of progesterone (P) therapy on clinical pregnancy rates as measured by the window of implantation (WOI) in the first cycle of frozen embryo transplantation. METHODS: The study compared the pregnancy rates between 345 cleavage stage transfers and 348 blastocyte transfers of frozen embryos with modified natural cycles in patients from July 1, 2020, to November 30, 2020. Four different P durations were analyzed in the cleavage stage embryo transfer group, i.e., two, three, four, and five days. Five different P durations were analyzed in the blastocyst transfer group, i.e., three, four, five, six, and seven days. RESULTS: The baseline demographics and clinical characteristics of the cleavage stage embryos and blastocyst transfer groups were not comparable. The clinical pregnancy rates following the cleavage stage embryo transfer after two, three, four, and five-day P administration were 45.71%, 44.60%, 38.40%, and 30.43%, respectively (the difference among the subgroups was not significant). Following the blastocyst transfer, the clinical pregnancy rates after three, four, five, six, and seven-day P administration were 50.65%, 63.51%, 60.00%, 54.55%, and 61.54%, respectively (the difference among the subgroups was not significant). In contrast, these two transfer groups showed significantly different clinical pregnancy rates following four and five-day P exposure (P < 0.05). CONCLUSION: For cleavage-stage embryo transfer, the most effective WOI was found between days two and five of P administration. The effective WOI for blastocyst transfer was observed between days three and seven of P administrations.
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Implantação do Embrião , Transferência Embrionária , Feminino , Humanos , Gravidez , Taxa de Gravidez , Estudos RetrospectivosRESUMO
Tensile properties and microstructure changes under different stress states of tempered 9Cr-F/M steel were characterized using a transmission electron microscope (TEM), electron backscatter diffraction (EBSD), scanning electron microscopy (SEM), Vickers hardness tester, and tensile tester. This tempered steel has a typical lath martensite structure with only a few polygonal ferrites embedded, and M23C6 and MX phases nucleated on the lath boundaries or within the sub-grains. At elevated temperatures, the strength of the steel decreases. However, the elongation at 400 °C is lower than that at room temperature. For the necking zone, tensile deformation made the grain elongated to the direction of applied stress and thus the grain's cross-section becomes smaller. For samples with rectangular working area cross-section, the deformation in the TD direction was more severe than that in the ND direction, which made the grain elongated in the TD direction. These results can provide some guidance for composition optimization of the 9Cr-F/M steel and facilitate a better understanding of the fracture mechanism under different stress states.
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Perovskite materials have a variety of crystal structures, and the properties of crystalline materials are greatly influenced by geometric information such as the space group, crystal system, and lattice constant. It used to be mostly obtained using calculations based on density functional theory (DFT) and experimental data from X-ray diffraction (XRD) curve fitting. These two techniques cannot be utilized to identify materials on a wide scale in businesses since they require expensive equipment and take a lot of time. Machine learning (ML), which is based on big data statistics and nonlinear modeling, has advanced significantly in recent years and is now capable of swiftly and reliably predicting the structures of materials with known chemical ratios based on a few key material-specific factors. A dataset encompassing 1647 perovskite compounds in seven crystal systems was obtained from the Materials Project database for this study, which used the ABX3 perovskite system as its research object. A descriptor called the bond-valence vector sum (BVVS) is presented to describe the intricate geometry of perovskites in addition to information on the usual chemical composition of the elements. Additionally, a model for the automatic identification of perovskite structures was built through a comparison of various ML techniques. It is possible to identify the space group and crystal system using just a small dataset of 10 feature descriptors. The highest accuracy is 0.955 and 0.974, and the highest correlation coefficient (R2) value of the lattice constant can reach 0.887, making this a quick and efficient method for determining the crystal structure.
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Li2ZrO3-coated and Al-doped micro-sized monocrystalline LiMn2O4 powder is synthesized through solid-state reaction, and the electrochemical performance is investigated as cathode materials for lithium-ion batteries. It is found that Li2ZrO3-coated LiAl0.06Mn1.94O4 delivers a discharge capacity of 110.90 mAhg-1 with 94% capacity retention after 200 cycles at room temperature and a discharge capacity of 104.4 mAhg-1 with a capacity retention of 87.8% after 100 cycles at 55 °C. Moreover, Li2ZrO3-coated LiAl0.06Mn1.94O4 could retain 87.5% of its initial capacity at 5C rate. This superior cycling and rate performance can be greatly contributed to the synergistic effect of Al-doping and Li2ZrO3-coating.
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In this work, FeCr-based films with different Y2O3 contents were fabricated using radio frequency (RF) magnetron sputtering. The effects of Y2O3 content on their microstructure and mechanical properties were investigated through scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), inductive coupled plasma emission spectrometer (ICP) and a nanoindenter. It was found that the Y2O3-doped FeCr films exhibited a nanocomposite structure with nanosized Y2O3 particles uniformly distributed into a FeCr matrix. With the increase of Y2O3 content from 0 to 1.97 wt.%, the average grain size of the FeCr films decreased from 12.65 nm to 7.34 nm, demonstrating a grain refining effect of Y2O3. Furthermore, the hardness of the Y2O3-doped FeCr films showed an increasing trend with Y2O3 concentration, owing to the synergetic effect of dispersion strengthening and grain refinement strengthening. This work provides a beneficial guidance on the development and research of composite materials of nanocrystalline metal with a rare earth oxide dispersion phase.