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Understanding the characteristics of waterlogging in urban agglomeration is essential for effective waterlogging prevention and management, as well as for promoting sustainable urban development. Previous studies have predominantly focused on the driving mechanisms of waterlogging in urban agglomeration at a single scale, but urban agglomeration space has greater spatio-temporal heterogeneity, it is often difficult to fully reveal such characteristics at a single scale. Consequently, this study endeavors to explore the spatio-temporal evolution characteristics and underlying mechanisms of waterlogging incidents within urban agglomerations by adopting a multi-scale analytical approach. The results indicate that: (1) The waterlogging degree and high-density zones increase in the GBA, and the waterlogging points are spatially polycentric. However, the waterlogging point in Hong Kong is decreasing. (2) The influence of ISP and AI on waterlogging is dominant at all scales, followed by RE and Slope. ISPâ©Slope and ISPâ©RE are the key interactions for waterlogging. (3) The aggregation of waterlogging decreases with grid scale, and the influence of land cover factors on waterlogging increases with grid scale. Moreover, the findings at the grid scale outperformed those at the watershed scale, indicating that the grid scale is more conducive to the investigation of waterlogging in urban agglomerations. This research broadens our comprehension of the mechanisms behind waterlogging in urban agglomeration and provide references for policy decisions on waterlogging prevention and mitigation within urban agglomerations.
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China's unprecedented rapid urbanization has dramatically reshaped the urban built environment, disrupting the thermal balance of cities. This disruption causes the urban heat island (UHI) effect, adversely affecting urban sustainability and public health. Although studies have highlighted the remarkable impacts of the built environment on UHIs, the specific effects of its various structures and components remain unclear. In this study, a multidimensional remote sensing data set was used to quantify the atmospheric UHIs across 335 Chinese cities from 1980 to 2020. In conjunction with stocks of three end-use sectors and three material groups, the impacts of gridded material stocks on UHI variations were analyzed. The findings reveal that building stocks exert a predominant influence in 48% of cities. Additionally, the extensive use of metal and inorganic materials has increased thermal stress in 220 cities, leading to an average UHI increase of 0.54 °C. The effect of organic materials, primarily arising from mobile heat sources, is continuously increasing. Overall, this study elucidates the effect of the functional structure and material composition of urban landscapes on UHIs, highlighting the complexities associated with the influence of the built environment on the urban heat load.
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Ambiente Construído , Cidades , Temperatura Alta , Urbanização , ChinaRESUMO
Rice protein peptides (RPP) are a potentially valuable source of high-quality calcium chelating properties. However, there is a lack of information regarding the calcium-absorption-promoting effect of RPP and its underlying mechanism. The present study adopted molecular docking methodologies to analyze the 10 most potent peptide segments from RPP. Results revealed that the peptide AHVGMSGEEPE (AHV) displayed optimal calcium binding properties (calcium-chelating capacity 55.69 ± 0.66 mg/g). Quantum chemistry analysis revealed that the AHV peptide effectively binds and forms stable complexes with calcium via the carbonyl oxygen atoms in valine at position 3 and the carbonyl of the C-terminal carboxyl group of glutamate at position 11. The spectral analysis results indicated that AHV may bind to calcium through carboxyl oxygen atoms, resulting in a transition from a smooth surface block-like structure to a dense granular structure. Furthermore, this study demonstrated that the 4 mmol/L AHV-Ca chelate (61.75 ± 13.23 µg/well) significantly increases calcium absorption compared to 1 mM CaCl2 (28.57 ± 8.59 µg/well) in the Caco-2 cell monolayer. In terms of mechanisms, the novel peptide-calcium chelate AHV-Ca derived from RPP exerts a cell-level effect by upregulating the expression of TRPV6 calcium-ion-channel-related genes and proteins (TRPV6 and Calbindin-D9k). This study provides a theoretical basis for developing functional foods with the AHV peptide as ingredients to improve calcium absorption.
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Cálcio , Oryza , Humanos , Cálcio/metabolismo , Células CACO-2 , Oryza/metabolismo , Simulação de Acoplamento Molecular , Cálcio da Dieta/metabolismo , Peptídeos/química , OxigênioRESUMO
An impact polypropylene copolymer (IPC), composed of polypropylene (PP) and ethylene-propylene copolymer (EPC), was synthesized through two-stage in-reactor polymerization. A systematic investigation of the crystalline structure, thermal behavior, morphology, and tensile properties of the IPC extruded cast film was conducted. Specifically, the morphology of EPC was obtained by confocal Raman imaging by depicting the spatial distribution of the Raman band located at 1064 cm-1. The EPC phase exhibits fibrous morphology with the long axis aligning along the machine direction (MD). A three-dimensional (3D) heterogeneous structure of the IPC cast film obtained by confocal Raman imaging confirms that the fibrous EPC phase is dispersed in a 3D framework of the PP matrix. The mesomorphic phase in the as-prepared cast film transforms to a stable α-form crystal after annealing at 130 °C, which improves the yield strength but decreases the elongation of the cast film. The WAXD and SAXS results indicate that there is no obvious orientation of the crystallites. Thus, the anisotropy of tensile properties in the MD and transverse directions is closely related to the anisotropic phase morphology at the micrometer scale. The results reveal that the mechanical performances of IPC films are determined by the crystalline structure of the PP matrix and the morphology.
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Understanding the regulation of transgene expression is critical for the success of plasmid-based gene therapy and vaccine development. In this study, we used two sets of plasmid vectors containing secreted embryonic alkaline phosphatase or the mouse IL-10 gene as a reporter and investigated the role of promoter elements in regulating transgene expression in vivo. We demonstrated in mice that hydrodynamic transfer of plasmids with the CMV promoter resulted in a high level of reporter gene expression that declined rapidly over time. In contrast, when plasmids with albumin promoters were used, a lower but sustained gene expression pattern was observed. We also found that plasmids containing a shorter CMV promoter sequence with fewer transcription factor binding sites showed a decrease in the peak level of gene expression without changing the overall pattern of reporter gene expression. The replacement of regulatory elements in the CMV promoter with a single regulatory element of the albumin promoter changed the pattern of transient gene expression seen in the CMV promoter to a pattern of sustained gene expression identical to that of a full albumin promoter. ChIP analyses demonstrated an elevated binding of acetylated histones and TATA box-binding protein to the promoter carrying regulatory elements of the albumin promoter. These results suggest that the strength of a promoter is determined by the number of appropriate transcription factor binding sites, while gene expression persistence is determined by the presence of regulatory elements capable of recruiting epigenetic modifying complexes that make the promoter accessible for transcription. This study provides important insights into the mechanisms underlying gene expression regulation in vivo, which can be used to improve plasmid-based gene therapy and vaccine development.
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Background: Consumer wearable devices such as wristbands and smartwatches have potential application value in communicable disease surveillance. Objective: We investigated the ability of wearable devices to monitor COVID-19 patients of varying severity. Methods: COVID-19 patients with mobile phones supporting wearable device applications were selected from Dalian Sixth People Hospital. Physiological parameters from the wearable devices and electronic questionnaires were collected from the device wearing until 14 days post-discharge. Clinical information during hospitalization was also recorded. Based on imaging data, the patients were categorized into the milder group without pneumonia and the more severe group with pneumonia. We plotted the curves of the physiological parameters of the two groups to compare the differences and changes. Results: Ninety-eight patients were included in the analysis. The mean age was 39.6 ± 10.5 years, including 45 males (45.9%). There were 24 asymptomatic patients, 10 mild patients, 60 moderate patients, and 4 severe patients. Compared with the milder group, the more severe group had higher heart rate-related parameters, while the heart rate variability (HRV) was the opposite. In the more severe group, the heart rate-related parameters showed a downward trend from 0 to 7 days after the fever resolution. Among them, the resting heart rate and sleep heart rate decreased on the 25th day after the onset and were close to the milder group 1 week after discharge. Conclusions: Consumer wearable devices have the potential to monitor respiratory infections. Heart rate-related parameters obtained from these devices can be sensitive indicators of COVID-19 severity and correlate with disease evolution. Trial registration: ClinicalTrials.gov NCT04459637.
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Chronic hepatitis B virus (HBV) poses a significant global health challenge as it can lead to acute or chronic liver disease and hepatocellular carcinoma (HCC). To establish a safety experimental model, a homolog of HBV-duck HBV (DHBV) is often used for HBV research. Hydrodynamic-based gene delivery (HGD) is an efficient method to introduce exogenous genes into the liver, making it suitable for basic research. In this study, a duck HGD system was first constructed by injecting the reporter plasmid pLIVE-SEAP via the ankle vein. The highest expression of SEAP occurred when ducks were injected with 5 µg/mL plasmid pLIVE-SEAP in 10% bodyweight volume of physiological saline for 6 s. To verify the distribution and expression of exogenous genes in multiple tissues, the relative level of foreign gene DNA and ß-galactosidase staining of LacZ were evaluated, which showed the plasmids and their products were located mainly in the liver. Additionally, ß-galactosidase staining and fluorescence imaging indicated the delivered exogenous genes could be expressed in a short time. Further, the application of the duck HGD model on DHBV treatment was investigated by transferring representative anti-HBV genes IFNα and IFNγ into DHBV-infected ducks. Delivery of plasmids expressing IFNα and IFNγ inhibited DHBV infection and we established a novel efficient HGD method in ducks, which could be useful for drug screening of new genes, mRNAs and proteins for anti-HBV treatment.
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Carcinoma Hepatocelular , Vírus da Hepatite B do Pato , Hepatite B Crônica , Neoplasias Hepáticas , Animais , Humanos , Carcinoma Hepatocelular/patologia , Patos/genética , Hepatite B Crônica/patologia , Neoplasias Hepáticas/patologia , Hidrodinâmica , Fígado , Vírus da Hepatite B do Pato/genética , beta-Galactosidase , DNA Viral/genéticaRESUMO
Transforming growth factor-ß (TGF-ß) and Hippo signaling are two critical pathways engaged in cancer progression by regulating both oncogenes and tumor suppressors, yet how the two pathways coordinately exert their functions in the development of hepatocellular carcinoma (HCC) remains elusive. In this study, we firstly conducted an integrated analysis of public liver cancer databases and our experimental TGF-ß target genes, identifying CYR61 as a pivotal candidate gene relating to HCC development. The expression of CYR61 is downregulated in clinical HCC tissues and cell lines than that in the normal counterparts. Evidence revealed that CYR61 is a direct target gene of TGF-ß in liver cancer cells. In addition, TGF-ß-stimulated Smad2/3 and the Hippo pathway downstream effectors YAP and TEAD4 can form a protein complex on the promoter of CYR61, thereby activating the promoter activity and stimulating CYR61 gene transcription in a collaborative manner. Functionally, depletion of CYR61 enhanced TGF-ß- or YAP-mediated growth and migration of liver cancer cells. Consistently, ectopic expression of CYR61 was capable of impeding TGF-ß- or YAP-induced malignant transformation of HCC cells in vitro and attenuating HCC xenograft growth in nude mice. Finally, transcriptomic analysis indicates that CYR61 can elicit an antitumor program in liver cancer cells. Together, these results add new evidence for the crosstalk between TGF-ß and Hippo signaling and unveil an important tumor suppressor function of CYR61 in liver cancer.
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Carcinoma Hepatocelular , Proteína Rica em Cisteína 61 , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas , Fator de Crescimento Transformador beta , Proteínas de Sinalização YAP , Animais , Humanos , Camundongos , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/genética , Linhagem Celular Tumoral , Movimento Celular , Proteína Rica em Cisteína 61/metabolismo , Proteína Rica em Cisteína 61/genética , Mineração de Dados , Regulação Neoplásica da Expressão Gênica/genética , Via de Sinalização Hippo , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/genética , Camundongos Nus , Regiões Promotoras Genéticas , Transdução de Sinais/genética , Proteína Smad2/metabolismo , Proteína Smad2/genética , Proteína Smad3/metabolismo , Proteína Smad3/genética , Fatores de Transcrição de Domínio TEA/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Fator de Crescimento Transformador beta/genética , Regulação para Cima , Proteínas de Sinalização YAP/metabolismo , Proteínas de Sinalização YAP/genéticaRESUMO
BACKGROUND: No studies have investigated whether high-sensitivity C reactive protein (hsCRP) can be used to predict the forced expiratory volume in 1 s (FEV1)/estimated value of FEV1 (FEV1%pred). This study aimed to assess the association between hsCRP and FEV1%pred in middle-aged and elderly individuals without underlying lung disease. METHODS: The data for this study were obtained from a prospective cohort study that included 1047 middle-aged and elderly citizens from Beijing aged 40-75 years without any evidence of underlying lung diseases with FEV1 >70% after receiving inhalational bronchodilators. The baseline analysis of the participants was performed from 30 May 2018 to 31 October 2018. Restricted cubic spline regression and multivariate linear regression models were used to assess the non-linear association and linear association between hsCRP and FEV1/FEV in 6 s (FEV6) and FEV1%pred, respectively. RESULTS: The hsCRP values of 851 participants were recorded; the values were normal in 713 (83.8%) participants. The remaining 196 participants (18.7%) had missing data. A non-linear association was observed between normal hsCRP values and FEV1/FEV6. hsCRP was linearly and negatively correlated with FEV1%pred, and each 1 SD increase in hsCRP was significantly associated with a 2.4% lower in FEV1%pred. Significantly higher FEV1/FEV6 differences were observed in the female subgroup than those in the male subgroup (p=0.011 for interaction). CONCLUSIONS: hsCRP had a non-linear association with FEV1/FEV6 and a linear negative association with FEV1%pred in individuals with normal hsCRP values. hsCRP can be used to predict FEV1%pred, which can be used to predict the development of chronic obstructive pulmonary disease. hsCRP has a stronger association with lung function in women than that in men. TRIAL REGISTRATION NUMBER: NCT03532893.
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Pneumopatias , Pulmão , Idoso , Pessoa de Meia-Idade , Humanos , Masculino , Feminino , Volume Expiratório Forçado , Pequim/epidemiologia , Estudos Prospectivos , Proteína C-ReativaRESUMO
OBJECTIVES: Morning dry mouth, commonly seen in Obstructive Sleep Apnea (OSA) patients, is absent in current OSA screening tools. This study evaluated the link between morning dry mouth and OSA's clinical symptoms and complications, aiming to determine its viability as a screening indicator. METHODS: This research analyses baseline data from a prospective cohort study (the PIFCOPD study). Demographic information, medical history, and the presence of morning dry mouth symptoms were collected. The STOP-Bang questionnaire was performed for OSA screening. Logistic regression analyses were employed to establish the correlations between morning dry mouth and the clinical symptoms and comorbidities of OSA. RESULT: 1291 participants (62.1±7.5 years; 501 males, 790 females) were included, of which 416 reported morning dry mouth (32.2%). 42.6% in the high-risk OSA group and 22.1% in the low-risk group reported morning dry mouth. Individuals with morning dry mouth also showed higher STOP-Bang scores (3.3±1.6 vs. 2.3±1.4, P<0.01). Significant associations were found between morning dry mouth and loud snoring, observed sleep apnea, daytime fatigue, and hyperlipidemia (P<0.01), but not with alcohol consumption, tea consumption, diabetes, or hypertension. CONCLUSION: Morning dry mouth is associated with increased OSA risk and its clinical signs, suggesting its potential as an OSA screening symptom. CLINICAL TRIAL REGISTRATION: This study has been registered at www.ClinicalTrials.gov (registration identifier: NCT03532893) on 21 May 2018.
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Apneia Obstrutiva do Sono , Xerostomia , Masculino , Feminino , Humanos , Estudos Transversais , Estudos Prospectivos , Comorbidade , Inquéritos e Questionários , Apneia Obstrutiva do Sono/epidemiologia , Apneia Obstrutiva do Sono/complicações , Xerostomia/epidemiologia , Xerostomia/complicações , Programas de RastreamentoRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: The Zishen Yutai pills (ZYP), a Chinese medicinal formulation derived from the Qing Dynasty prescription "Shou Tai pills", have been documented to exhibit beneficial effects in clinical observations treating premature ovarian failure (POF). However, the anti-POF effects and its comprehensive systemic mechanism have not yet been clarified. AIM OF THE REVIEW: Therapeutic effects and systemic mechanism of ZYP in POF were evaluated. MATERIALS AND METHODS: After pulverization, sieving, and stirring, ZYP was administered intragastrically to cisplatin-induced POF mice at a dose of 1.95 mg/kg/d for 14 days. The anti-POF effects of ZYP were investigated by assessing the number of ovarian follicles at different developmental stages, as well as measuring serum estradiol (E2) levels and ovarian-expressed anti-Müllerian hormone (AMH). Reproductive performance and offspring health were evaluated to predict fertility restoration. Furthermore, a combination of proteomic and metabolomic profiling was employed to elucidate the underlying molecular mechanism of ZYP in treating POF. Western blot (WB) analyses and real-time quantitative polymerase chain reaction (RT-qPCR) were conducted to explore the mechanisms through which ZYP exerted its anti-POF effects. RESULTS: We have demonstrated that oral administration of ZYP reversed the reduction in follicles at different developmental stages and stimulated the expressions of serum E2 and ovarian-expressed AMH in a cisplatin-induced POF model. Additionally, ZYP ameliorated follicle apoptosis in ovaries affected by cisplatin-induced POF. Furthermore, treatment with ZYP restored the quantity and quality of oocytes, as well as enhanced fertility. Our results revealed 62 differentially expressed proteins (DEPs) through proteomic analyses and identified 26 differentially expressed metabolites (DEMs) through metabolomic analyses. Both DEPs and DEMs were highly enriched in the arachidonic acid (AA) metabolism pathway. ZYP treatment effectively upregulated the protein and mRNA expression of critical targets in AA metabolism and the AKT pathway, including CYP17α1, HSD3ß1, LHR, STAR, and AKT, in cisplatin-induced POF mice. CONCLUSIONS: These results indicated that ZYP exerted protective effects against POF and restored fertility from cisplatin-induced apoptosis. ZYP could be a satisfying alternative treating POF.
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Medicamentos de Ervas Chinesas , Menopausa Precoce , Insuficiência Ovariana Primária , Feminino , Humanos , Camundongos , Animais , Insuficiência Ovariana Primária/induzido quimicamente , Insuficiência Ovariana Primária/tratamento farmacológico , Insuficiência Ovariana Primária/metabolismo , Ácido Araquidônico , Proteínas Proto-Oncogênicas c-akt/metabolismo , Cisplatino/efeitos adversos , Proteômica , Fertilidade , Hormônio AntimüllerianoRESUMO
AIMS: The increasing resistance to anti-seizure medications (ASMs) and the ambiguous mechanisms of epilepsy highlight the pressing demand for the discovery of pioneering lead compounds. Berberine (BBR) has received significant attention in recent years within the field of chronic metabolic disorders. However, the reports on the treatment of epilepsy with BBR are not systematic and the mechanism remains unclear. MAIN METHODS: In this study, the seizure behaviors of mice were recorded following subcutaneous injection of pentetrazol (PTZ). Non-targeted metabolomics was used to analyze the serum metabolites based on ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). Meanwhile, multivariate statistical methods were used for metabolite identification and pathway analysis. Furthermore, network pharmacology, molecular docking, and quantitative real-time PCR assay were used for the target identification. KEY FINDINGS: BBR had anti-seizure effects on PTZ-induced seizure mice after long-term treatment. Tryptophan metabolism and phenylalanine metabolism were involved in regulating the therapeutic effects of BBR. SIGNIFICANCE: This study reveals the potential mechanism of BBR for epilepsy treatment based on non-targeted metabolomics and network pharmacology, which provides evidence for uncovering the pathogenesis of epilepsy, suggesting that BBR is a potential lead compound for anti-epileptic treatment.
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Berberina , Epilepsia , Camundongos , Animais , Berberina/farmacologia , Berberina/uso terapêutico , Berberina/metabolismo , Farmacologia em Rede , Simulação de Acoplamento Molecular , Metabolômica/métodos , Pentilenotetrazol/toxicidade , Epilepsia/induzido quimicamente , Epilepsia/tratamento farmacológico , Convulsões/induzido quimicamente , Convulsões/tratamento farmacológicoRESUMO
INTRODUCTION: One-third of people with epilepsy continue to experience seizures despite treatment with existing anti-seizure medications (ASMs). The failure of modern ASMs to substantially improve epilepsy prognosis has been partly attributed to overreliance on acute rodent models in preclinical drug development as they do not adequately recapitulate the mechanisms of human epilepsy, are labor-intensive and unsuitable for high-throughput screening (HTS). There is an urgent need to find human-relevant HTS models in preclinical drug development to identify novel anti-seizure compounds. OBJECTIVES: This paper developed high-throughput preclinical screening models to identify new ASMs. METHODS: 14 natural compounds (α-asarone, curcumin, vinpocetine, magnolol, ligustrazine, osthole, tanshinone IIA, piperine, gastrodin, quercetin, berberine, chrysin, schizandrin A and resveratrol) were assessed for their ability to suppress epileptiform activity as measured by multi-electrode arrays (MEA) in neural cultures derived from human induced pluripotent stem cells (iPSCs). In parallel, they were tested for anti-seizure effects in zebrafish and mouse models, which have been widely used in development of modern ASMs. The effects of the compounds in these models were compared. Two approved ASMs were used as positive controls. RESULTS: Epileptiform activity could be induced in iPSCs-derived neurons following treatment with 4-aminopyridine (4-AP) and inhibited by standard ASMs, carbamazepine, and phenytoin. Eight of the 14 natural compounds significantly inhibited the epileptiform activity in iPSCs-derived neurons. Among them, piperine, magnolol, α-asarone, and osthole showed significant anti-seizure effects both in zebrafish and mice. Comparative analysis showed that compounds ineffective in the iPSCs-derived neural model also showed no anti-seizure effects in the zebrafish or mouse models. CONCLUSION: Our findings support the use of iPSCs-derived human neurons for first-line high-throughput screening to identify compounds with anti-seizure properties and exclude ineffective compounds. Effective compounds may then be selected for animal evaluation before clinical testing. This integrated approach may improve the efficiency of developing novel ASMs.
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As a major load-bearing component of trains, the weld quality of the bogie beam is critical to the safety of railway operations. This study specifically investigates the inertia friction welding process of S355 bogie crosshead tubes, with the aim of improving the weld quality and achieving one-time formation of the crosshead tube and tube seat. The microstructural features and mechanical properties of S355 inertia-welded joints were also compared with the base metal. Research indicates that inertia friction welds have no visible defects, and that the microstructure of the welding seam (WS) consists of granular bainite, acicular ferrite and little pearlite. The thermo-mechanically affected zone (TMAZ) consists of granular bainite bands and ferrite + pearlite bands. The hot work strengthening mechanism of inertia friction welding results in a higher level of hardness for both WS and TMAZ. The tensile property of the welded joints can be compared to the base metal. The yield strength, tensile strength and elongation of the welded joints, respectively, reach 87.5%, 100% and 79.5% of S355. However, the impact toughness of the welds at room temperature is lower than that of the base material, particularly in the TMAZ zone. Conversely, in an environment with a temperature of -40 °C, WS's impact toughness surpasses that of the parent material.
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We have previously developed a non-viral episomal vector based on matrix attachment region (MAR) that can facilitate plasmid replication episomally in mammal cells. In this study, we have focused on the development of an alternative tissue specific episomal vector by incorporating into cis-acting elements. We found that AAT promoter demonstrated the highest eGFP expression level in HepG2, Huh-7 and HL-7702 hepatic cells. Furthermore, hCMV enhancer when combined with AAT promoter significantly improved the eGFP expression level in the transfected HepG2 cells. The mean fluorescence intensity of eGFP in hCMV2 group was 1.33 fold, which was higher than that of the control (p < 0.01), followed by the hCMV1 group (1.21 fold). In addition, the percentages of eGFP-expressing cells in hCMV1 and hCMV2 groups were observed to be 49.3% and 57.2%, which were significantly higher than that of the enhancer-devoid control vector (44.3%) (p < 0.05). Moreover, the eGFP protein were up to 3.5 fold and 5.1 fold (p < 0.05), respectively. This observation could be related with the activities of some specific transcription factors (TFs) during the transcriptional process, such as SRF, REL and CREB1. The composite CMV/AAT promoter can be thus used for efficient transgene expression of MAR-based episomal vector in liver cells and as a potential gene transfer tools for the management of liver diseases. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03774-x.
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Pandemic of COVID-19 hit China at the end of 2022. According to China Center for Disease Control and Prevention, Omicron BA.5.2 and BF.7 were the main circulating variants. Chinese people had a high COVID-19 vaccination rate, and the most widely used vaccines were CoronaVac (Sinovac) and BBIBP-CorV (Sinopharm). An online questionnaire was distributed to survey the vaccination history and infection information of China mainland residents during this pandemic. A total of 4250 subjects were included for propensity score matching, 566 unvaccinated subjects and 1072 vaccinated subjects were finally included to analyze the effects of the two vaccines on BA.5.2 and BF.7. The SARS-CoV-2 infection rate was 84.5% in the vaccinated group and 82.3% in the unvaccinated group (p = 0.255). Vaccinated subjects had significantly higher rates of COVID-19-related symptoms, including fever, cough, nasal obstruction, runny nose, and sore throat. However, vaccinated people had lower risk of pneumonia (odds ratio [OR]: 0.467, 95% confidence interval [CI]: 0.286-0.762) and hospitalization (OR: 0.290, 95% CI: 0.097-0.870) due to COVID-19. In general, the current study did not observe the protective effect of CoronaVac and BBIBP CorV against BA.5.2 and BF.7 infection. However, these vaccines can still reduce the risk of adverse outcomes such as pneumonia and hospitalization.
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COVID-19 , Vacinas , Humanos , SARS-CoV-2 , Vacinas contra COVID-19 , COVID-19/epidemiologia , COVID-19/prevenção & controle , Estudos Retrospectivos , China/epidemiologiaRESUMO
Macroscopic elastic moduli (i.e., bulk modulus and shear modulus) of covalent crystals are mainly determined by microscopic structures and stiffnesses. Herein, the microscopic bond and angle force constants of covalent crystals were parameterized from their atomic electronegativities, which is named the electronegativity force field (EFF). Based on this force field, the elastic moduli of covalent crystals can be directly obtained by molecular mechanics calculations. The calculated moduli for various covalent crystals are generally consistent with first-principles calculations, while the computational cost is reduced by several orders of magnitude, indicating the accuracy and efficiency of the EFF. Finally, we found 25 ultrahigh-modulus crystals with a bulk modulus greater than 350 GPa, which demonstrates that this force field can be used for screening of ultrahigh-modulus materials from numerous crystal candidates.
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In this study, post-welding aging treatments were applied to a novel Ni-based superalloy GH4065A inertia friction welding (IFW) joint to improve its high-temperature properties. The effect of aging treatment on the microstructure and creep resistance of the IFW joint was systematically investigated. The results indicated that the original γ' precipitates in the weld zone almost completely dissolved during the welding process, and fine tertiary γ' precipitated during the subsequent cooling process. Aging treatment did not significantly change the characteristics of grain structures and primary γ' in the IFW joint. After aging, the size of tertiary γ' in the weld zone and secondary γ' in the base material increased, but their morphology and volume fraction did not change evidently. After 760 °C, 5 h aging treatment, the tertiary γ' in the weld zone of the joint grew from 12.4 nm to 17.6 nm. Correspondingly, the creep rupture time of the joint at 650 °C and 950 MPa increased from 7.51 h to 147.28 h, which is about 19.61 times higher than that of the as-welded joint. The creep rupture was more likely to occur in the base material instead of the weld zone for the IFW joint. This revealed that the creep resistance of the weld zone was significantly improved after aging due to the growth of tertiary γ'. However, increasing the aging temperature or extending the aging time promoted the growth of secondary γ' in the base material, and meanwhile, M23C6 carbides tended to continuously precipitate at the grain boundaries of the base material. It might decrease the creep resistance of the base material.
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Artificial neural networks (ANNs) have been an important approach for predicting the value of flow stress, which is dependent on temperature, strain, and strain rate. However, there is still a lack of sufficient knowledge regarding what structure of ANN should be used for predicting metal flow stress. In this paper, we train an ANN for predicting flow stress of In718 alloys at high temperatures using our experimental data, and the structure of the ANN is optimized by comparing the performance of four ANNs in predicting the flow stress of In718 alloy. It is found that, as the size of the ANN increases, the ability of the ANN to retrieve the flow stress results from a training dataset is significantly enhanced; however, the ability to predict the flow stress results absent from the training does not monotonically increase with the size of the ANN. It is concluded that the ANN with one hidden layer and four nodes possesses optimized performance for predicting the flow stress of In718 alloys in this study. The reason why there exists an optimized ANN size is discussed. When the ANN size is less than the optimized size, the prediction, especially the strain dependency, falls into underfitting and fails to predict the curve. When the ANN size is less than the optimized size, the predicted flow stress curves with the temperature, strain, and strain rate will contain non-physical fluctuations, thus reducing their prediction accuracy of extrapolation. For metals similar to the In718 alloy, ANNs with very few nodes in the hidden layer are preferred rather than the large ANNs with tens or hundreds of nodes in the hidden layers.
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Automotive electrification holds the promise of mitigating transportation-related greenhouse gas (GHG) emissions, yet at the expense of growing demand for critical metals. Here, we analyze the trade-off between the decarbonization potential of the road transportation sector and its critical metal requirement from the demand-side perspective in 48 major countries committing to decarbonize their road transportation sectors aided by electric vehicles (EVs). Our results demonstrate that deploying EVs with 40-100% penetration by 2050 can increase lithium, nickel, cobalt, and manganese demands by 2909-7513%, 2127-5426%, 1039-2684%, and 1099-2838%, respectively, and grow platinum group metal requirement by 131-179% in the 48 investigated countries, relative to 2020. Higher EV penetration reduces GHG emissions from fuel use regardless of the transportation energy transition, while those from fuel production are more sensitive to energy-sector decarbonization and could reach nearly "net zero" by 2040.