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Two-dimensional material-supported single metal atom catalysts have been extensively studied and proved effective in electrocatalytic reactions in recent years. In this work, we systematically investigate the OER catalytic properties of single metal atoms supported by the NiN2 monolayer. Several typical transition metals with high single atom catalytic activity, such as Fe, Co, Ru, Rh, Pd, Ir, and Pt, were selected as catalytic active sites. The energy calculations show that transition metal atoms (Fe, Co, Ru, Rh, Pd, Ir, and Pt) are easily embedded in the NiN2 monolayer with Ni vacancies due to the negative binding energy. The calculated OER overpotentials of Fe, Co, Ru, Rh, Pd, Ir and Pt embedded NiN2 monolayers are 0.92 V, 0.47 V, 1.13 V, 0.66 V, 1.25 V, 0.28 V, and 0.94 V, respectively. Compared to the 0.57 V OER overpotential of typical OER noble metal catalysts IrO2, Co@NiN2 and Ir@NiN2 exhibit high OER catalytic activity due to lower overpotential, especially for Ir@NiN2. The high catalytic activity of the Ir embedded NiN2 monolayer can be explained well by the d-band center model. It is found that the adsorption strength of the embedded TM atoms with intermediates follows a linear relationship with their d-band centers. Besides, the overpotential of the Ir embedded NiN2 monolayer can be further reduced to 0.24 V under -2% biaxial strain. Such findings are expected to be employed in more two-dimensional material-supported single metal atom catalyzed reactions.
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Understanding how the electronic state of transition metal atoms can influence molecular adsorption on a substrate is of great importance for many applications. Choosing NH3 as a model molecule, its adsorption behavior on defected SnS2 monolayers is investigated. The number of valence electrons n is controlled by decorating the monolayer with different transition metal atoms, ranging from Sc to Zn. Density-Functional Theory based calculations show that the adsorption energy of NH3 molecules oscillates with n and shows a clear odd-even pattern. There is also a mirror symmetry of the adsorption energies for large and low electron numbers. This unique behavior is mainly governed by the oxidation state of the TM ions. We trace back the observed trends of the adsorption energy to the orbital symmetries and ligand effects which affect the interaction between the 3σ orbitals (NH3) and the 3d orbitals of the transition metals. This result unravels the role which the spin state of TM ions plays in different crystal fields for the adsorption behavior of molecules. This new understanding of the role of the electronic structure on molecular adsorption can be useful for the design of high efficiency nanodevices in areas such as sensing and photocatalysis.
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Low activity and poor product selectivity of CO2 reduction have seriously hampered its further practical application. Introducing p-block atoms to the catalyst is regarded as a promising strategy due to the versatility of p orbitals and diversity of p-block elements. Here, we systematically studied the influence of p-block atom X (X = C, N, O, S, and Se) on CO2 catalytic properties on a Sn(200) surface by first-principles calculation. Our work shows that all the p-block atoms are relative stable with Ef in the range of -5.11 to -3.59 eV. Further calculation demonstrates that the diversity of the p-block atoms results in unique CO2 electrocatalytic activity and product selectivity. Interestingly, the p-block C atom shows bi-functional activity to form two-electron products HCOOH and CO, with the corresponding energy barriers remarkably low at about 0.19 eV and 0.28 eV. In particular, the p-block S(Se) atom appears to have striking HCOOH selectivity, with the energy barrier to form HCOOH only a quarter of that to form the CO product. This unusual behavior is mainly attributed to the adsorption strength and frontier orbital interaction between the p-block atom and intermediates. These findings can effectively provide a valuable insight into the design of highly efficient CO2 electrocatalyst.
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BACKGROUND: Allergic rhinitis (AR) is a worldwide health problem. Allergen avoidance is strongly recommended for AR patients. Air purification can reduce concentrations of particles in indoor air, including those of allergens. Air purifiers have been recommended by clinicians for AR patients, but few studies have focused on the removal of airborne allergens from home environments. Such studies have been limited by a lack of blinding, small samples, or a failure to measure allergen levels, disease activity, or a combination of these factors. This study investigates the efficacy of a high-efficiency air purifier in reducing disease activity in the homes of AR patients sensitive to the allergens produced by Artemisia (mugwort) pollen. METHODS: This is a randomized, double-blind, clinical controlled trial that will test active and inactive versions of an air purifier (Atmosphere®; Amway China). Sixty AR patients sensitive to the allergens produced by Artemisia pollen will be assigned randomly to two groups of equal numbers. All patients will undergo a 4-week treatment period and a 4-week observation period. Evaluation will be conducted at baseline (day 0) and on days 7, 14, 21, 28, and 56. The primary outcome measure will be the difference in visual analog scale scores from baseline. Secondary outcomes will be changes from baseline in nasal symptoms, allergy symptom scores, responses to the Rhinoconjunctivitis Quality of Life Questionnaire, Epworth Sleepiness Scale scores, and tolerability scores for the air purifier. Side effects of treatment will be recorded. DISCUSSION: Reducing exposure to allergens can reduce the risk of conditions such as AR. We hypothesise that AR patients sensitive to the allergens produced by Artemisia pollen will not suffer symptoms in a pollen-free environment. AR patients can remove pollen from their homes using air purifiers, decreasing the risk of symptoms. We expect that our study results will provide reliable evidence for determining the effects of air-purification therapy. TRIAL REGISTRATION: ChiCTR-INR-17012481 . (Retrospectively registered 26 August 2017).
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Filtros de Ar , Poluição do Ar em Ambientes Fechados/prevenção & controle , Alérgenos/efeitos adversos , Artemisia/efeitos adversos , Pólen/efeitos adversos , Rinite Alérgica/prevenção & controle , Alérgenos/análise , China , Protocolos Clínicos , Método Duplo-Cego , Humanos , Rinite Alérgica/etiologiaRESUMO
OBJECTIVE: To investigate the activation of NALP3 inflammasome in the process of experimental pulmonary fibrosis (PF), and evaluate the effect of sodium ferulate (SF) in the relationship of NALP3 and PF. METHODS: Establishing PF experimental model via bleomycin (BLM) intratracheal injection (BLM group, SF group), treated with SF daily (SF group) or PBS [BLM group, control (CON) group] and mice were executed on day 21. Ashcroft score was used to assess lung fibrosis in mice PF model. The content of hydroxyproline (HYP) in lung tissue was determined by alkaline hydrolysis. Fibroblast NIH-3T3 was treated with H2O2 to trigger cell oxidative stress in vitroexperiments (H2O2group). Cell was pre-administrated with SF 2 h before H2O2 stimulation in H2O2+SF group. Blank group without any treatments, was set as control. Real time-PCR was used to investigate the expressions of three elements of inflammasome[NALP3, caspase-1, apoptosis-associated speck-like protein (ASC)], collagen-1 and α smooth muscle actin (α-SMA) mRNA in both lung tissue and fibroblast. Western blot was used to detect protein level of NALP3 in mice lung tissue and collagen-1, α-SMA in fibroblast as well. Meanwhile, IL-1ß content in lung tissue and cell supernatant was measured by ELISA. RESULTS: in vitro experiment, SF treated mice showed lower Ashcroft score and HYP content and decreased NALP3, ASC, caspase-1 mRNA expressions and IL-1ß production, NALP3 protein level compared with BLM group (P<0.05). in vitroexperiment, H2O2 increased NALP3 (P<0.05), ASC (P<0.01), caspase-1 (P<0.05) expressions and IL-1ß releasing (P<0.05)and promoted the expressions of collagen-1 and α-SMA in both gene and protein levels (P<0.05) in NIH-3T3. NALP3 activation was partly inhibited in H2O2+SF group (P<0.05). The mRNA expression levels of collagen-1 and α-SMA were reduced in H2O2+SF group (P<0.05) and the protein expressions of α-SMA and collagen-1 were decreased (P<0.05) compared with those of H2O2 group. CONCLUSION: Sodium ferulate may suppress oxidative stress mediated NALP3 activation to inhibit fibroblast activation in the anti-fibrosis effect.
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Ácidos Cumáricos/farmacologia , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Fibrose Pulmonar/tratamento farmacológico , Actinas/metabolismo , Animais , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Caspase 1/metabolismo , Colágeno Tipo I/metabolismo , Peróxido de Hidrogênio , Hidroxiprolina/análise , Camundongos , Células NIH 3T3 , Estresse Oxidativo , Fibrose Pulmonar/metabolismoRESUMO
In virtue of the severity and scale of the pollution caused by oil pool flame, space remote sensing can provide us a new way of monitoring in real time the oil pool flame pollution. Space remote sensing monitoring is based on the analysis of target spectrum characteristics. Due to lack of adequate researches on the characteristics of infrared spectrum of oil pool flame, this paper carries out the analytical study on flame spectrums of several types of oil, mixed oil and other combustible objects in outdoor space by establishing all-flame infrared testing system with the spectrum range of 1ï½14 µm. The results show that the spectrum curves of oil pool flame of 92# gasoline, 95# gasoline, 0# diesel, aviation kerosene and lube have similar features, that there exist characteristics emission peaks at the area of certain wave lengthsH2O characteristics emission peak for 1.1, 2.4, 2.8 and 6.3 µm, CO2 characteristics emission peak for 4.2 and 4.5 µm, CH stretching vibration emission peak for 3.4 µm, and no obvious characteristics peak for spectrum curves of 6.3 µm and above; that there is no obvious difference in the spectrum of oil pool flame among the mixtures of 92# gasoline and 0# diesel at different proportions, that the comparison of the flame spectrum of 92# gasoline with that of wood and paper shows that there appears a characteristics emission peak at 3.4 µm; that though the flame spectrum of alcohol has similar radiated emission near 3.4 µm, the proportion of its radiation intensity to that of CO2 at 4.5 µm is far less than that for the flame spectrum of 92# gasoline; that the flame spectrum of honeycomb briquette is similar to that of gray body radiation. The differences in flame spectrum among all kinds of combustible materials are closely linked to their chemical compositions and burning reaction mechanisms. Comparative analysis on the spectrum characteristics at continuous area, intermission area and flue gas area shows that CH stretching vibration peak only exists in continuous area, which proves that the emission peak is caused by the combustible reaction of oil and gas. This result is in line with the mechanism of oil pool combustion reaction. The experimental conclusion is of great significance in the remote-sensing recognition of oil pool flame based on the analysis of spectrum characteristics.
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OBJECTIVES: Study the gene and protein expression of NACHT-PYD-containing protein 3 (NALP3) inflammasome and extracellular regulated protein kinase (ERK), the intervention effects of sodium ferulate (SF) in human lung epithelial cells A549 under oxidative stress, and to investigate the possible mechanism. METHODS: Human lung epithelial cells A549 cultured in vitro were divided into 6 groups, including control group,H2O2(200 umol/L) group, SF group (400 ug/mL), caspase-1 blockers (Z-VAD) group (Z-VAD 20 umol/L+H2O2200 umol/L), ERK blockers (PD98059) group (PD98059 50 umol/L+H2O2 200 umol/L), and SF+H2O2 group (SF 400 ug/mL+H2O2 200 umol/L). Fluorescent quantitative real-time PCR (qRT-PCR) was performed to detect the mRNA levels of caspase-1 and NALP3, the expression of caspase-1, NALP3, phosphorylated ERK p-ERK, ERK protein were evaluated by Western blot. The level of interleukin-1 ß (IL-1ß) were detected by ELISA. RESULTS: Compared with the control group,H2O2 not only increased the mRNA and protein expression levels of caspase-1 and NALP3 and the protein expression levels of p-ERK/ERK, but also enhanced the secretion of IL-1ß in human lung epithelial cells A549 (P<0.05),while SF group showed no statistic significance of those indicators above (P>0.05). The Z-VAD group, the PD98059 group and the SF+H2O2 group resisted the effects of H2O2 on A549 cells by decreasing the mRNA and protein expressions of caspase-1 and NALP3,and the protein expression of p-ERK/ERK, as well as reducing the secretion of IL-1ß(P<0.05),when compared with the H2O2 group. CONCLUSIONS: SF may reduce the expression of caspase-1, NALP3 and IL-1ß by inhibiting ERK, so as to reduce the inflammation caused by oxidative stress.
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Ácidos Cumáricos/farmacologia , Inflamassomos/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Estresse Oxidativo , Células A549 , Flavonoides/farmacologia , Humanos , Peróxido de Hidrogênio/farmacologia , Inflamassomos/metabolismo , Interleucina-1beta/metabolismoRESUMO
BACKGROUND: Metabolic syndrome (MetSyn) increases the incidence of cardiovascular disease. Information on changes in prevalence of MetSyn in developing countries is limited. This study aims to compare MetSyn prevalence and its associated vascular risk over the period between 2002 and 2010 in a population which has had the world's fastest economic development over the past three decades. METHODS: Two health surveys were conducted by using the multistage cluster random sampling method in a Chinese population of 85 million in southern China. The participants received a full medical check-up, including measurement of blood pressure (BP), obesity indices, fasting lipids and glucose levels. Data describing socio-economic status and lifestyle factors were also collected through interview. Metabolic syndrome was defined in accordance with the International Diabetes Federation criteria. RESULTS: A total of 3,561 participants from Survey 2010 were included in the data analysis. Women had a significantly higher prevalence of MetSyn than men. Comparison between the two surveys shows that age-standardized prevalence of MetSyn increased fourfold (from 5.4% in 2002 to 21.3% in 2010) in those ⧠20 years. Among the MetSyn components, prevalence of hyperglycaemia has increased most (from 9.1% to 53.1%). The age-standardized prevalence of central obesity, hypertension, hypertriglyceridaemia and low HDL-cholesterol increased from 13.5% to 25.4%, from 23.6% to 40.8%, from 12.1% to 17.4% and from 32.1% to 71.1%, respectively. Differences between rural and urban residents in the prevalence in MetSyn and its components narrowed in 2010. CONCLUSIONS: Cardiovascular risk escalated dramatically in this population between 2002 and 2010. The escalation may relate to the rapid economic development, which led to accelerating changes in nutrition, lifestyle, and socio-economic status. Our findings suggest that health transition in rapidly developing second- and third-world countries may be much faster than what has been observed in Western countries.
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Povo Asiático/estatística & dados numéricos , Doenças Cardiovasculares/epidemiologia , Desenvolvimento Econômico , Nível de Saúde , Síndrome Metabólica/epidemiologia , Adulto , Doenças Cardiovasculares/economia , Causalidade , China/epidemiologia , Diabetes Mellitus/epidemiologia , Feminino , Inquéritos Epidemiológicos , Humanos , Hiperglicemia/epidemiologia , Hipertensão/epidemiologia , Incidência , Masculino , Síndrome Metabólica/economia , Pessoa de Meia-Idade , Obesidade/epidemiologia , Obesidade Abdominal , Prevalência , Fatores de Risco , População Rural/estatística & dados numéricosRESUMO
Understanding the behavior of a polaron in contact with water is of significant importance for many photocatalytic applications. We investigated the influence of water on the localization and transport properties of polarons at the rutile (110) surface by constrained density functional theory. An excess electron at a dry surface favors the formation of a small polaron at the subsurface Ti site, with a preferred transport direction along the [001] axis. As the surface is covered by water, the preferred spatial localization of the polarons is moved from the subsurface to the surface. When the water coverage exceeds half a monolayer, the preferred direction of polaron hopping is changed to the [110] direction toward the surface. This characteristic behavior is related to the Ti3d-orbital occupations and crystal field splitting induced by different distorted structures under water coverage. Our work describes the reduced sites that might eventually play a role in photocatalysis for rutile (110) surfaces in a water environment.
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The need for low-carbon solar electricity production has become increasingly urgent for energy security and climate change mitigation. However, the bandgap and carrier separation critical requirements of high-efficiency solar cells are difficult to satisfy simultaneously in a single material. In this work, several van der Waals ZnIn2X4 (X = S, Se, and Te) heterostructures were designed based on density functional theory. Our results suggest that both ZnIn2S4/ZnIn2Se4 and ZnIn2Se4/ZnIn2Te4 heterostructures are direct bandgap semiconductors at the Γ point. Besides, obvious carrier spatial separations were observed in the ZnIn2S4/ZnIn2Se4 and ZnIn2Se4/ZnIn2Te4 heterostructures. Interestingly, the ZnIn2S4/ZnIn2Se4 heterostructure has a suitable bandgap of 1.43 eV with good optical absorption in the visible light range. The calculated maximum theoretical photoelectric conversion efficiency of ZnIn2S4/ZnIn2Se4 heterostructure was 32.1%, and it can be further enhanced to 32.9% under 2% tensile strain. Compared to single-layer ZnIn2X4 materials, the electron effective mass of the ZnIn2S4/ZnIn2Se4 heterostructure is relatively low, which results in high electron mobility in the heterostructure. The suitable bandgap, obvious carrier separation, high electron mobility, and excellent theoretical photoelectric conversion efficiency of the ZnIn2S4/ZnIn2Se4 heterostructure make it a promising candidate for novel 2D-based photoelectronic devices and solar cells.
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PURPOSE: Current health care reforms in China have an overall goal of strengthening primary care through the establishment and expansion of primary care networks based on community health centers (CHCs). Implementation in urban areas has led to the emergence of different models of ownership and management. The objective of this study was to evaluate the primary care experiences of patients in the Pearl River Delta as measured by the Primary Care Assessment Tool (PCAT) and the relationships with ownership and management in the 3 different models we describe. METHODS: This cross-sectional study was conducted on-site at CHCs in 3 cities within the Pearl River Delta, China, using a multistage cluster sampling method. A validated Mandarin Chinese version of the PCAT-Adult Edition (short version) was adopted to collect information from adult patients regarding their experiences with primary care sources. PCAT scores for individual primary care attributes and total primary care assessment scores were assessed with respect to sociodemographic characteristics, health characteristics, and health care service utilization across 3 primary care models. RESULTS: One thousand four hundred forty (1,440) primary care patients responded to the survey, for an overall response rate of 86.1%. Respondents gave government-owned and -managed CHCs the highest overall PCAT scores when compared with CHCs either managed by hospitals (95.18 vs 90.81; P = .005) or owned by private and social entities (95.18 vs 90.69; P =.007) as a result of better first-contact care (better first-contact utilization) and coordination of care (better service coordination and information system). Factors that were positively and significantly associated with higher overall assessment scores included the presence of a chronic condition (P <.001), having medical insurance (P = .006), and a self-reported good health status (P <.001). CONCLUSIONS: This study suggests that government-owned and -managed CHCs may be able to provide better first-contact care in terms of utilization and coordination of care, and may be better at solving the problem of underutilization of the CHCs as the first-contact point of care, one key problem facing the reforms in China.
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Atitude Frente a Saúde , Centros Comunitários de Saúde/normas , Ambulatório Hospitalar/normas , Atenção Primária à Saúde/normas , Garantia da Qualidade dos Cuidados de Saúde , Adulto , Idoso , China , Centros Comunitários de Saúde/organização & administração , Estudos Transversais , Feminino , Programas Governamentais/organização & administração , Programas Governamentais/normas , Humanos , Masculino , Pessoa de Meia-Idade , Ambulatório Hospitalar/organização & administração , Atenção Primária à Saúde/organização & administração , Inquéritos e QuestionáriosRESUMO
PURPOSE: Obesity has been recognized as a significant risk factor for postmenopausal breast cancer. The aim of this study is to investigate the prognostic significance of body mass index (BMI) in hormone receptor-positive, operable breast cancer. METHODS: In this retrospective cohort study, 1,192 consecutive patients with curative resection of primary breast cancer were enrolled. Patients were assigned to two groups according to BMI: normal or underweight (BMI < 23.0 kg/m²) and overweight or obese (BMI ≥ 23.0 kg/m²). Associations among BMI and clinicopathological characteristics and prognosis of patients were assessed. RESULTS: A high BMI was significantly (P < 0.01) correlated with age, nodal stage, ALNR, ER positivity, PR positivity and menopausal status at diagnosis. Univariate analysis revealed that BMI, pathologic T stage, nodal stage, axillary lymph node ratio (ALNR) and adjuvant radiotherapy history were significantly (P < 0.05) associated with disease-free survival and overall survival, irrespective of tumour hormone receptor status. Multivariate analysis revealed BMI as an independent prognostic factor in all cases and in hormone receptor-positive cases. CONCLUSION: A high BMI (≥ 23.0 kg/m²) is independently associated with poor prognosis in hormone receptor-positive breast cancer.
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Índice de Massa Corporal , Neoplasias da Mama/patologia , Neoplasias da Mama/fisiopatologia , Obesidade/patologia , Obesidade/fisiopatologia , Adulto , Neoplasias da Mama/cirurgia , Feminino , Humanos , Pessoa de Meia-Idade , Obesidade/cirurgia , Estudos RetrospectivosRESUMO
Objective: To investigate the distribution and drug resistance of pathogens among hospitalized patients in the respiratory unit during the COVID-19 pandemic, analyze the risk factors of drug resistance, construct a risk prediction model. Methods: This study isolated 791 strains from 489 patients admitted to the Affiliated Hospital of Chengdu University, who were retrospectively enrolled between December 2019 and June 2021. The patients were divided into training and validation sets based on a random number table method (8:2). The baseline information, clinical characteristics, and culture results were collected using an electronic database and WHONET 5.6 software and compared between the two groups. A risk prediction model for drug-resistant bacteria was constructed using multi-factor logistic regression. Results: K. pneumoniae (24.78%), P. aeruginosa (17.19%), A. baumannii (10.37%), and E. coli (10.37%) were the most abundant bacterial isolates. 174 isolates of drug-resistant bacteria were collected, ie, Carbapenem-resistant organism-strains, ESBL-producing strains, methicillin-resistant S. aureus, multi-drug resistance constituting 38.51%, 50.57%, 6.32%, 4.60%, respectively. The nosocomial infection prediction model of drug-resistant bacteria was developed based on the combined use of antimicrobials, pharmacological immunosuppression, PCT>0.5 ng/mL, CKD stage 4-5, indwelling catheter, and age > 60 years. The AUC under the ROC curve of the training and validation sets were 0.768 (95% CI: 0.624-0.817) and 0.753 (95% CI: 0.657-0.785), respectively. Our model revealed an acceptable prediction demonstrated by a non-significant Hosmer-Lemeshow test (training set, p=0.54; validation set, p=0.88). Conclusion: K. pneumoniae, P. aeruginosa, A. baumannii, and E. coli were the most abundant bacterial isolates. Antimicrobial resistance among the common isolates was high for most routinely used antimicrobials and carbapenems. COVID-19 did not increase the drug resistance pressure of the main strains. The risk prediction model of drug-resistant bacterial infection is expected to improve the prevention and control of antibacterial-resistant bacterial infection in hospital settings.
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OBJECTIVE: To explore clinical effect of high-intensity laser therapy(HILT) combined with targeted hand function training on pain and lateral pinch force in grade 1-2 thumb carpometacarpal(CMC) osteoarthritis(OA). METHODS: From April 2020 and April 2022, 42 female patients with thumb CMC OA grade 1 to 2, aged from 58 to 80 years old with an everage of (68.90±7.58) years old were divided into observation group of 21 patients who received HILT and targeted hand function training for 4 weeks, and 21 patients in control group who received ultrashort wave therapy combined with using of an orthosis for 4 weeks. Visual analogue scale(VAS) was applied to evaluate degree of pain, function of finger was evaluated by dynamometer to measure lateral pinch force at baseline, immediately following intervention at 4 and 12 weeks following intervention. RESULTS: VAS and lateral pinch force at immediately and 12 weeks after intervention betwwen two groups were better than that of before intervention(P<0.05). Compared with control group, the degree of pain in observation group improved more(immediately after intervention t=3.37, P<0.05, 12 weeks after intervention t=9.05, P<0.05), lateral pinch force higher than that of control group (immediately after intervention t=-2.55, P<0.05, 12 weeks after intervention t=9.51, P<0.05). CONCLUSION: High-intensity laser therapy combined with targeted hand function training is more effective than traditional methods in improving pain and lateral pinch force in grade 1-2 thumb carpometacarpal osteoarthritis.
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Terapia a Laser , Osteoartrite , Humanos , Feminino , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Polegar , Braquetes , Osteoartrite/terapia , DorRESUMO
Two-dimensional Ruddlesden-Popper (2D RP) perovskites can form layered protective materials using long organic cations as "barrier" caps, which is expected to solve the problem of instability of perovskites in the working environment. In this work, we systematically studied the 2D Ruddlesden-Popper (C6H5CH2NH3)2PbI4 hybrid perovskites using density functional theory. The results reveal that the 2D (C6H5CH2NH3)2PbI4 perovskites are semiconductors with band gaps of 2.22 eV. The optical absorption peak of the 2D (C6H5CH2NH3)2PbI4 perovskite structure is located at 532 nm in the visible region. Interestingly, the optical absorption spectrum of the 2D (C6H5CH2NH3)2PbI4 perovskite structure enhanced under suitable strains. The highest optical absorption peak appears in 2D (C6H5CH2NH3)2PbI4 under a -2% strain, and its theoretical photoelectric conversion efficiency is 28.5%. More interestingly, the replacement of surface I atoms with Br is another ways to enhance the optical absorption spectrum of the 2D (C6H5CH2NH3)2PbI4 perovskite structure. The optical absorption peak blue-shifts to the high energy region, which has higher solar energy flux density than the low energy region. The good stability, tuneable band gap and excellent theoretical photoelectric conversion efficiency of the 2D (C6H5CH2NH3)2PbI4 perovskite structure make it a promising candidate for novel 2D hybrid perovskite based photoelectronic devices and solar cells.
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BACKGROUND: Sebaceous carcinoma (SC), a malignancy primarily characterized by aggressive growth, affects cutaneous tissues of the periocular region. Extraocular SC is extremely rare, especially in the extremities, as evidenced by only a handful of reported cases. CASE SUMMARY: A 65-year-old man presented with a rapidly enlarging swelling on the left inner thigh, which was initially misdiagnosed as a subcutaneous abscess. The lesion had appeared two months prior to admission. Clinical examination revealed a cauliflower-like swollen content, with an ulcerated and infected mass located on his left thigh. At the same time, we observed solitary nodular lesions in his lungs and brain, with biopsy pathology of the lung lesions found to be consistent with the mass in the thigh. The patient received chemotherapy comprising cis-platinum with fluorouracil, followed by targeted therapy with anlotinib hydrochloride and chemotherapy with vinorelbine, implantation of iodine-125 seeds in the thigh and pulmonary tumor. The initial stage intervention achieved partial remission. The efficacy of maintenance treatment was evaluated as stable disease after the first 5 cycles; however, the patient developed a new brain lesion after the sixth cycle of treatment, which resulted in progressive disease and he received whole brain gamma knife radiotherapy. CONCLUSION: We analyzed the clinical presentation, imaging features, pathology and treatment of a rare case of lung, brain and lymph node metastasis of SC located in the thigh. It is evident that cis-platinum combined with fluorouracil, vinorelbine combined with anlotinib hydrochloride may be an effective therapeutic regimen in advanced SC. However, brain metastatic lesions should receive early radiotherapy.
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Designing photocatalysts with suitable band alignment and considerable carrier mobility is extremely important. Here, by means of first-principles calculation, we systematically investigated the structural, photoelectronic, and carrier mobility behavior of the two-dimensional Janus MoSSe/WSSe superlattice. The results show that both armchair-type (AN-SL) and zigzag-type (ZN-SL) superlattices are relatively stable with negative Ef values in the range of -2.35 to -1.16 eV. Band gap and band edge position calculations demonstrate that these superlattices are completely suitable for water splitting by visible light. Particularly, the interface contact of the superlattice can be spontaneously changed from type-I to type-II when N > 4, facilitating separation of photogenerated carriers. Furthermore, the hole carrier mobility (µh) in AN-SL can be effectively regulated from 1200 to 2200 cm2 V-1 s-1, much larger than that of the isolated components. Interestingly, the disparity of hole/electron carrier mobility is remarkably large with an approximately 20-fold difference, showing the potential in prohibiting the recombination of photogenerated carriers. This unique behavior is further illustrated by the relaxation times of carriers, where the lifetime of hole carriers is about 7 times larger than that of electron carriers. These findings suggest that forming a Janus superlattice is a promising approach for regulating the photoelectronic properties of semiconductors, providing a promising way to design high efficiency photocatalysts.
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Two-dimensional Janus MXY materials have been successfully synthesized from their parent species by CVD, SEAR, or PLD techniques. However, their detailed evolution process and underlying atomistic mechanism are far from understood conclusively, which are prompts for further research. Here, taking Janus MoSSe as a representation, the evolution process from MoS2 is systematically investigated by first-principles calculation. The simulation shows that the lowest formation energy of MoS(2-δ)Seδ increases with selenylation ratio δ. Unexpectedly, Se atoms prefer to form a pair in next-nearest neighboring state (Se-NN-Se), eventually transferred into a growth rule of (6n + 1) during the evolution process. Particularly, it is demonstrated that the stability of the intermediate is mainly governed by the Mo 4d orbitals in different distorted triangular crystal fields, rendering a different degree of orbital splitting. Both the occupied and unoccupied Mo 4d orbitals of Se-NN-Se are farther from the Fermi level than other cases, which is clearly illustrated by d-band center theory. These findings will be helpful to understand the evolution process and the underlying atomistic mechanism of Janus MXY.
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The Schottky barrier height (ESBH) is a crucial factor in determining the transport properties of semiconductor materials and it directly regulates the carrier mobility in opto-electronics devices. In principle, van der Waals (vdW) Janus heterostructures offer an appealing avenue for controlling the ESBH. However, the underlying atomistic mechanisms are far from understood conclusively, which prompts further research in the topic. To this end, here we carry out an extensive first-principles study of the electronic properties and ESHB of several vdW Janus MXY/graphene (M = Mo, W; X, Y = S, Se, Te) heterostructures. The results of the simulations show that by changing the composition and geometry of the heterostructure's interface, it is possible to control its electrical contact, and thence electron transport properties, from ohmic to Schottky with up to a factor seven variation in the ESBH. Detailed analysis of the simulations enables rationalization of this highly attractive property on the basis of the interplay between the permanent dipole moment of the Janus MXY sheet and the induced one due to interfacial charge redistribution at the MXY/Gr interface. Such an interplay is shown to be highly effective in altering the electrostatic potential difference across the vdW Janus heterostructure, determining its ESBH, and thence Schottky (ohmic) contact type. These computational findings contribute guidelines to control the electrical contacts in Janus heterostructures towards the rational design of electrical contacts in nanoscale devices.
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Fascin, an actin-cross-linking protein, is up-regulated in breast cancer and correlates with a more aggressive disease. This study was conducted to elucidate the effects of manipulating fascin in breast cancer cells on the metastasis-associated events, including proliferation, adhesion, invasion, epithelial-mesenchymal transition (EMT) and enrichment of a CD44(+) /CD24(-) subpopulation that show some stem/progenitor cell properties. Western blot analysis of a panel of breast cancer cell lines revealed high expression of fascin in MDA-MB-435 and MDA-MB-231 cells but revealed no or low expression in MDA-MB-453, Her-18 and T47D. Gain-of-function and loss-of-function studies in breast cancer cells demonstrated that forced expression of fascin promoted cell proliferation assessed by the MTT assay, decreased cellular adhesion to fibronectin and potentiated the invasive capacity in the Transwell chamber invasion assay. Conversely, down-regulation of fascin via small interfering RNA increased cell adhesion and facilitated cell proliferation and invasion. In addition, fascin participated in the EMT and modulated the proportion of the CD44(+) /CD24(-) subpopulation in breast cancer cells. In conclusion, our data highlight an important role for fascin in breast cancer progression in vitro through orchestrating a variety of cellular events associated with metastasis, and thus, targeting this gene might have therapeutic implications.