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Background: Early mobilization is one of the essential components of enhanced recovery after surgery (ERAS) pathways and has been shown to reduce complications and optimize patient outcomes. However, the effect of early mobilization for patients who undergo trans-femoral cardiac catheterization and the time for optimal mobilization timing remains controversial. We aimed to identify the safety of early mobilization and provide the optimum timing for early mobilization for patients undergoing trans-femoral cardiac catheterization. Methods: We searched MEDLINE, EMBASE, PubMed, Web of Science, Cochrane databases of systematic reviews, CINAHL, SCOPUS, China National Knowledge Infrastructure (CNKI), Wan Fang Database, and Chinese Science and Technology Periodical Database (VIP) comprehensively for randomized controlled trials associated with early mobilization, to explore its effects on patients after a trans-femoral cardiac catheterization. The risk of bias and heterogeneity of studies was assessed using the Revised Cochrane risk-of-bias tool for randomized trials (RoB 2) and I 2 index, respectively. The comprehensive Meta-analysis (CMA) was adopted to perform the meta-analysis. Results: We identified 14 trials with 2653 participants. Early mobilization was associated with significant decrease in back pain (mean difference (MD) = 0.634, 95% CI: 0.23-1.038; p = 0.002), especially in patients receiving instruction for early mobilization in 3 h~4 h versus 5 h~6 h (MD = 0.737, 95% CI: 0.431-1.043; p = 0.000) and 12 h versus 24 h (OR = 5.504, 95% CI: 1.646-18.407; p = 0.006) categories. The results of subgroup analysis also showed a significant risk reduction in urinary retention by early mobilization in 12 h versus 24 h (OR = 5.707, 95% CI: 1.859-17.521; p = 0.002) category. Conclusions: Early mobilization has not been shown to increase the risk of bleeding, hematoma, pseudoaneurysm, urinary retention, and pain at the puncture site after trans-femoral cardiac catheterization. Early mobilization is a practical initiative in ERAS, and it may be safe and feasible to advance the mobilization to 2 h~4 h.
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BACKGROUND: Scoping reviews have emerged as a valuable method for synthesizing emerging evidence, providing a comprehensive contextual overview, and influencing policy and practice developments. The objective of this study is to provide an overview of scoping reviews conducted in Chinese academic institutions over the last decades. METHOD: We conducted a comprehensive search of nine databases and six grey literature databases for scoping reviews conducted in Chinese academic institutions. The reporting quality of the included reviews was assessed using the Preferred Reporting Items for PRISMA-ScR checklist. We performed both quantitative and qualitative analyses, examining the conduct of the scoping reviews and exploring the breadth of research topics covered. We used Chi-squared and Wilcoxon rank-sum tests to compare methodological issues and reporting quality in English and Chinese-language reviews. RESULTS: A total of 392 reviews published between 2013 and 2022 were included, 238 English-reported reviews and 154 Chinese-reported reviews, respectively. The primary purposes of these reviews were to map and summarize the evidence, with a particular focus on health and nursing topics. 98.7% of reviews explicitly used the term "scoping review", and the Arksey and O'Malley framework was the most frequently cited framework. Thirty-five English-reported scoping reviews provided a protocol for scoping review. PubMed was the most common source in English-reported reviews and CNKI in Chinese-reported reviews. Reviews published in English were more likely to search the grey literature (P = 0.005), consult information specialists (P < 0.001) and conduct an updated search (P = 0.012) than those in Chinese. Reviews published in English had a significantly high score compared to those published in Chinese (16 vs. 14; P < 0.001). The reporting rates in English-reported reviews were higher than those in Chinese reviews for seven items, but lower for structured summary (P < 0.001), eligibility criteria (P < 0.001), data charting process (P = 0.009) and data items (P = 0.015). CONCLUSION: There has been a significant increase in the number of scoping reviews conducted in Chinese academic institutions each year since 2020. While the research topics covered are diverse, the overall reporting quality of these reviews is need to be improved. And there is a need for greater standardization in the conduct of scoping reviews in Chinese academic institutions.
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Revisiones Sistemáticas como Asunto , China , Bases de Datos Factuales , Lenguaje , Revisiones Sistemáticas como Asunto/normasRESUMEN
BACKGROUND: The TyG index is an indicator of insulin resistance (IR), which is associated with the development and prognosis of cardiovascular disease. This study aimed to summarize the relationship between the TyG index and the risk, severity, and prognosis of coronary artery disease (CAD) by performing a systematic review and meta-analysis. METHODS: The PubMed, EMBASE, The Cochrane Library, and Web of Science databases were searched for articles published from inception until May 1, 2023. Cross-sectional studies, retrospective or prospective cohort studies recruiting patients with CAD were included. For the analysis of CAD severity, the outcomes were coronary artery calcification, coronary artery stenosis, coronary plaque progression, multi-vessel CAD, and in-stent re-stenosis. For the analysis of CAD prognosis, the primary outcome was major adverse cardiovascular events (MACE). RESULTS: Forty-one studies were included in this study. Compared to patients with the lowest TyG index, those with the highest TyG index had a higher CAD risk [odds ratio (OR): 1.94, 95% confidence interval (CI) 1.20-3.14, I2 = 91%, P = 0.007]. Additionally, these patients were more likely to have stenotic coronary arteries (OR: 3.49, 95% CI 1.71-7.12, I2 = 0%, P = 0.0006), progressed plaques (OR: 1.67, 95% CI 1.28-2.19, I2 = 0%, P = 0.002), and with more vessels involved (OR: 2.33, 95% CI 1.59-3.42, I2 = 0%, P < 0.0001). When calculated as a categorized variable, it appears that acute coronary syndrome (ACS) patients with higher TyG index levels may have a higher incidence rate of MACE [hazard ratio (HR): 2.09, 95% CI 1.68-2.62, I2 = 87%, P < 0.00001], whereas chronic coronary syndrome (CCS) or stable CAD patients with higher TyG index levels showed a trend towards an increased incidence rate of MACE (HR: 1.24, 95% CI 0.96-1.60, I2 = 85%, P = 0.09). When calculated as a continuous variable, ACS patients had an HR of 2.28 per 1-unit/1-standard deviation increment of the TyG index (95% CI 1.44-3.63, I2 = 95%, P = 0.0005). Similarly, CCS or stable CAD patients had an HR of 1.49 per 1-unit/1-standard deviation increment of the TyG index (95% CI 1.21-1.83, I2 = 75%, P = 0.0001). Myocardial infarction with non-obstructive coronary arteries patients had an HR of 1.85 per 1-unit increment of the TyG index (95% CI 1.17-2.93, P = 0.008). CONCLUSIONS: The TyG index is a simple new synthetic index that has been proven to be a valuable tool in the whole-course management of CAD patients. Patients with higher TyG index levels are at a higher risk of CAD, more severe coronary artery lesions, and worse prognosis compared to those with lower TyG index levels.
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Síndrome Coronario Agudo , Enfermedad de la Arteria Coronaria , Placa Aterosclerótica , Humanos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/epidemiología , Glucosa , Estudios Retrospectivos , Triglicéridos , Estudios Prospectivos , Estudios Transversales , Factores de Riesgo , Medición de Riesgo , Pronóstico , Placa Aterosclerótica/complicaciones , Síndrome Coronario Agudo/complicaciones , Glucemia/análisis , BiomarcadoresRESUMEN
BACKGROUND: Antenatal depression (AD) is common in pregnant women and is associated with adverse outcomes for the mother, fetus, infant and child. The influencing factors of AD among pregnant women have been studied; however, the mechanisms of these factors remain unclear. This study was designed to examine the direct and serial mediating roles of coping styles in the relationship between perceived social support and AD among pregnant women. METHODS: A cross-sectional study was conducted among 1486 pregnant women who registered to give birth at a tertiary hospital. A self-developed questionnaire was administered to obtain sociodemographic and obstetric data. The Perceived Social Support Scale (PSSS), Simplified Coping Style Questionnaire (SCSQ), and Edinburgh Postnatal Depression Scale (EPDS) were administered to measure the perceived social support, coping styles, and depressive symptoms of pregnant women, respectively. Multiple linear stepwise regression analysis was used, and then, the specific relationships among influencing factors were determined through structural equation modelling (SEM). RESULTS: The prevalence of AD was 24.02%. The average scores of intrafamily support, extrafamily support, positive coping styles, negative coping styles and EPDS reported by pregnant women were 24.16 ± 3.09, 44.52 ± 6.16, 27.34 ± 4.89, 9.79 ± 3.82, and 7.44 ± 3.56, respectively. Multiple regression analysis showed that pregnant women with a higher level of intrafamily support exhibited a positive coping style and a decreased risk of AD. Compared with extrafamily support, the direct effect (-0.16 vs. -0.10, P < 0.05) and indirect effect of intrafamily support through coping styles (-0.028 vs. -0.027, P < 0.05) on AD were stronger. Two indirect pathways explained 17.46% of the variance in the EPDS scores. CONCLUSION: Higher social support decreased the likelihood of AD, not only directly but also through the mediating roles of coping styles. Social support should be strengthened, and positive coping styles should be advocated in every stage of pregnancy. Specifically, intrafamily support should be given more attention for pregnant Chinese women.
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Adaptación Psicológica , Depresión/psicología , Mujeres Embarazadas/psicología , Apoyo Social , Adulto , Pueblo Asiatico/etnología , China/epidemiología , Estudios Transversales , Femenino , Humanos , Análisis de Clases Latentes , Embarazo/psicología , Escalas de Valoración PsiquiátricaRESUMEN
INTRODUCTION: The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach was developed to assess the certainty (or quality) of evidence and strength of recommendations in guidelines and endorsed internationally as a standard. Some guidelines had been developed to promote pressure injury prevention. AIMS: We explored whether and to what extent the development of pressure injury prevention guidelines had followed or been informed by the GRADE approach. If this approach was not used, we examined which other methods were used instead. METHODS: A cross-sectional study of pressure injury prevention guidelines was conducted. PubMed, Embase, CINAHL, and Chinese databases as well as guideline repositories and websites of professional bodies were searched for guidelines from 1990 to 2020. The grading systems of the certainty (or quality) of evidence and strength of recommendations of included guidelines were extracted. For the GRADE approach guidelines, compliance was assessed with the GRADE application criteria. RESULTS: Twenty guidelines were identified. Among them, four guidelines (20%) indicated the use of the GRADE approach. The compliance rate ranged from 33.3%-94.4%. Other approaches, such as the Scottish Intercollegiate Guidelines Network (SIGN) approach, were also used. CONCLUSION: The GRADE approach is rarely followed and inconsistently applied in pressure injury prevention guidelines. Other systems, such as the SIGN approach, are being used despite being outdated or inconsistent. Strategies for further uptake and appropriate application of the GRADE approach among guideline developers are needed in the future.
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Medicina Basada en la Evidencia , Úlcera por Presión , Humanos , Estudios Transversales , Medicina Basada en la Evidencia/métodosRESUMEN
AIMS: The aim of this study is to investigate the situation and perceptions of nursing directors about emergency nursing staff deployment in designated hospitals during the pandemic of COVID-19 in mainland China. BACKGROUND: The pandemic of COVID-19 has significantly depleted health care resources, leading to increased burden of nursing care and staffing and exacerbating the crisis in health care facilities. Currently, how to effectively plan and schedule nursing staffing in the pandemic still remains unknown. METHODS: From 14 July 2020 to 8 September 2020, 62 nursing directors of designated hospitals in mainland China were invited to participate in a cross-sectional online survey for their perceptions of nursing human-resource allocation during the pandemic of COVID-19. RESULTS: A total of 55 valid questionnaires were collected, showing that 96.36% of the hospitals had emergency nursing organizations and management systems during the pandemic, 96.36% had well-established scheduling principles for nursing human resources and 54.55% of hospitals had human-resource scheduling platforms. All the hospitals had trained emergency nursing staff in infection control (55, 100%), work process (51, 92.73%) and emergency skills (50, 90.91%). Most of the participants were satisfied with the nursing staffing deployments at their institutions (52, 94.55%). However, more than two thirds of them believed that their human-resource deployment plans need further improvements (39, 70.91%). CONCLUSIONS: Most of the designated hospitals investigated had established emergency nursing organizations, and management systems, and related regulations for the epidemic. However, the contents mentioned above still need to be further standardized. IMPLICATIONS FOR NURSING MANAGEMENT: The surge of patients in the epidemic was considerable challenge for the emergency capacity of hospitals. In the future, we should pay more attention to the following aspects: building emergency nursing staffing platforms, increasing emergency human-resource reserves, establishing reliable communication channels for emergency response teams, improving the rules and regulations of emergency human-resource management, offering more training and drills for emergency-related knowledge and skills and giving more focus on bio-psycho-social wellbeing of nurses.
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COVID-19 , Personal de Enfermería en Hospital , COVID-19/epidemiología , China/epidemiología , Estudios Transversales , Humanos , Pandemias , Admisión y Programación de PersonalRESUMEN
Tooth-related inflammatory disorders, including caries, pulpitis, apical periodontitis (AP), and periodontitis (PD), are primarily caused by resident oral microorganisms. Although these dental inflammatory conditions are typically not life-threatening, neglecting them can result in significant complications and greatly reduce an individual's quality of life. Nuclear factor κB (NF-κB), a family formed by various combinations of Rel proteins, is extensively involved in inflammatory diseases and even cancer. This study reviews recent data on NF-κB signaling and its role in dental pulp stem cells (DPSCs), dental pulp fibroblasts (DPFs), odontoblasts, human periodontal ligament cells (hPDLCs), and various experimental animal models. The findings indicate that NF-κB signaling is abnormally activated in caries, pulpitis, AP, and PD, leading to changes in related cellular differentiation. Under specific conditions, NF-κB signaling occasionally interacts with other signaling pathways, affecting inflammation, bone metabolism, and tissue regeneration processes. In summary, data collected over recent years confirm the central role of NF-κB in dental inflammatory diseases, potentially providing new insights for drug development targeting NF-κB signaling pathways in the treatment of these conditions. Keywords: NF-κB, dental caries, pulpitis, apical periodontitis, periodontitis.
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Caries Dental , FN-kappa B , Periodontitis Periapical , Periodontitis , Transducción de Señal , Humanos , FN-kappa B/metabolismo , Caries Dental/metabolismo , Caries Dental/patología , Caries Dental/inmunología , Periodontitis/metabolismo , Periodontitis/inmunología , Periodontitis/patología , Animales , Periodontitis Periapical/metabolismo , Periodontitis Periapical/patología , Periodontitis Periapical/inmunología , Pulpitis/metabolismo , Pulpitis/patología , Pulpitis/inmunología , Pulpa Dental/inmunología , Pulpa Dental/metabolismo , Pulpa Dental/patología , Inflamación/metabolismo , Inflamación/inmunologíaRESUMEN
Background: The lymphocyte-to-monocyte ratio (LMR) has been proposed as a novel prognostic factor in malignancies and cardiovascular diseases. Our study aimed to ascertain whether LMR is a useful biomarker in discriminating the hypertrophic cardiomyopathy (HCM) patients at higher risk of all-cause mortality. Methods: This retrospective study consisted of 354 adult HCM patients. Cox's proportional hazards regression models were used to analyze the association between LMR and all-cause mortality. Smooth curve fitting was conducted to explore the linear relationship between LMR and all-cause mortality. Results: During the follow-up, 44 patients reached the study endpoint. The all-cause mortality rate was 7.3 per 100 person-years in the first tertile and decreased across the three tertiles of LMR. With the first tertile as reference, adjusted hazard ratios (HR) for all-cause mortality were 0.43 for the second tertile (95% CI [0.20-0.91], p = 0.027) and 0.39 for the third tertile (95% CI [0.17-0.90], p = 0.028), respectively. Smooth curve fitting exhibited a nonlinear relationship between LMR values and all-cause mortality. For LMR < 6.5, per SD increase resulted in a significantly decreased risk of all-cause mortality by 62% (HR: 0.38, 95% CI [0.21-0.68]). For LMR ≥ 6.5, the all-cause mortality risk did not progressively increase. Stratified and subgroup analyses revealed similar results to the main analyses,andE-value analysis suggested robustness to unmeasured confounding. Conclusions: The study demonstrated that LMR was an independent predictor of all-cause mortality in HCM patients, and LMR may be useful for identifying HCM patients at high mortality risk.
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Cardiomiopatía Hipertrófica , Monocitos , Adulto , Humanos , Estudios Retrospectivos , Recuento de Linfocitos , Linfocitos , Cardiomiopatía Hipertrófica/diagnósticoRESUMEN
The dynamic interactions between drug carrier molecules and a cell membrane can not be ignored in their clinical use. Here a simple, label-free and non-invasive approach, photo-voltage transient method, combined with the atomic force microscopy, dynamic giant unilamellar vesicle leakage assay and cytotoxicity method, was employed for a real-time monitoring of the interaction process. Two representative polymer molecules, polyoxyethylene (35) lauryl ether (Brij35) and polyvinylpyrrolidone (PVPk30), were taken as examples to interact with a phospholipid bilayer membrane in a low ionic strength and neutral pH condition. Brij35 demonstrated an adsorption-accumulation-permeabilization dominated process under the modulation of polymer concentration in the solution. In contrast, PVPk30 performed a dynamic balance between adsorption-desorption of the molecules and/or permeabilization-resealing of the membrane. Such difference explains the high and low cytotoxicity of them, respectively, in the living cell tests. Briefly, through combining the photo-voltage approach with conventional fluorescent microscopy method, this work demonstrates new ideas on the time and membrane actions of polymer surfactants which should be taken into account for their biomedical applications.
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Fosfolípidos , Polímeros , Adsorción , Portadores de Fármacos , TensoactivosRESUMEN
OBJECTIVES: To identify the barriers to and facilitators of secondary prevention among people with coronary heart disease from the perspectives of nurses. DESIGN: A qualitative descriptive design using face-to-face semistructured interviews. SETTING: This study was conducted in China from October to November 2021. PARTICIPANTS: Registered nurses who had experience conducting secondary prevention for coronary heart disease were purposively recruited. Twelve nurses from 10 hospitals participated in this study. The data were analysed using content analysis based on the Theoretical Domains Framework. RESULTS: Based on the Theoretical Domains Framework, barriers to and facilitators of secondary prevention were identified within four key themes: nurse attributes (eg, knowledge and skills, motivation), patient characteristics (eg, age, education and economic conditions), the environmental context and resources (eg, organisational support, including financial support, clarity of responsibilities) and social influence (eg, economic development level, patient feedback). CONCLUSIONS: This research highlights the importance of nurses' motivation for delivering preventive care. Organisations should provide adequate support and establish a quality management system to maintain the quality of secondary prevention.
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Enfermedad Coronaria , Enfermeras y Enfermeros , Enfermedad Coronaria/prevención & control , Hospitales , Humanos , Investigación Cualitativa , Prevención SecundariaRESUMEN
INTRODUCTION: Small-molecular drugs are extensively used in cancer therapy, while they have issues of nonspecific distribution and consequent side effects. Nanomedicines that incorporate chemotherapeutic drugs have been developed to enhance the therapeutic efficacy of these drugs and reduce their side effects. One of the promising strategies is to prepare nanomedicines by harnessing the unique tumor microenvironment (TME). AREAS COVERED: The TME contains numerous cell types that specifically express specific antibodies on the surface. The physicochemical environment is characterized with a low pH, hypoxia, and a high redox potential resulting from tumor-specific metabolism. Therefore, intelligent nanomedicines designed based on the characteristics of the tumor microenvironment can be divided into two groups: the first group which is rapidly responsive to extracellular chemical/biological factors in the TME and the second one which actively and/or specifically targets cellular components in the TME. EXPERT OPINION: In this paper, we review recent progress of nanomedicines by harnessing the TME and illustrate the principles and advantages of different strategies for designing nanomedicines, which are of great significance for exploring novel nanomedicines or translating current nanomedicines into clinical practice. We will discuss the challenges and prospects of preparing nanomedicines to utilize or alter the TME for achieving effective, safe anticancer treatment.
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Antineoplásicos , Neoplasias , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Sistemas de Liberación de Medicamentos , Humanos , Nanomedicina/métodos , Neoplasias/tratamiento farmacológico , Microambiente TumoralRESUMEN
To understand the possible perturbations of graphene oxide (GO) nanosheets on cell membranes is the first step to evaluate their cytotoxicity, while the membrane heterogeneity such like lipid phase separation complicates such interactions. Using the dynamic giant unilamellar vesicle leakage assays, atomic force microscopy characterizations, and molecular dynamics simulations, we demonstrated the structural and property disturbance of GO on a lipid bilayer membrane in a low ionic strength and neutral pH condition, specifically the influence of lipid phase on this process. GO tends to obliquely insert into and even be sandwiched between leaflets of a liquid-phase membrane, inducing formidable flaw in lipid packing states and fast transmembrane leakage. However, GO adopts parallel adsorption or vertical insertion on/into a gel-phase bilayer, while permeabilization occurs only when the disturbance is strong enough. Our results are helpful to understand the fundamental interaction mechanism between GO nanosheets and cells.
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Grafito , Fosfolípidos , Membrana Dobles de Lípidos , Microscopía de Fuerza AtómicaRESUMEN
The existing cholesterols (Chols) in animal cell membranes play key roles in many fundamental cellular processes, which also promise the possibility to modulate the bioactivity of various membrane-active biomacromolecules. Here, combining dynamic giant unilamellar vesicle leakage experiments and molecular dynamics simulations, the inhibitory effect of Chols on the membrane poration activity of melittin (Mel), a typical natural antimicrobial peptide, is demonstrated. Molecular details of the Mel-Chol interactions in membrane show that, for a Chol-contained lipid membrane, Mel exposure would perturb the symmetric bilayer structure of the membrane and specifically influence the location and orientation distributions of Chol molecules to an asymmetric state between the two leaflets; moreover, the Mel-Chol interactions are significantly influenced by the membrane environment such as unsaturation degree of the lipid components. Such inhibitory effect is normally ascribed to an accumulation of Chol molecules around the membrane-bound peptide chains and formation of Chol-Mel complexes in the membrane, which hinder the further insertion of peptides into the membrane. This work clarifies the molecular interactions between membrane-active peptides and Chol-contained membranes, and suggest the possibility to develop targeted drugs due to the membrane component specificity between bacterial and animal cells.
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Many fundamental biological processes occur on cell membranes, and a typical example is the membrane permeabilization by peptides for an antimicrobial purpose. Previous studies of the underlying mechanism mostly focus on structural changes of membranes and peptides during their interactions. Herein, from a new perspective of single-molecule dynamics, the real-time three-dimensional motions of individual phospholipid and peptide molecules were monitored, and specifically, their correlation with the membrane poration function of melittin, a most representative natural antimicrobial peptide, was studied. We found that the adsorption and accumulation of melittin on the membrane surface significantly sped up the lateral diffusion of lipids surrounding the peptides, which in turn facilitated the peptide insertion at such heterogeneous regions. A unique "U"-bending pathway of melittin during membrane insertion and the ultimate formation of toroidal pores with dynamical translocations of peptides and lipids with several metastable states between the two leaflets of bilayer were observed.
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Membrana Dobles de Lípidos/metabolismo , Meliteno/metabolismo , Fosfatidilcolinas/metabolismo , Liposomas Unilamelares/metabolismo , Adsorción , Difusión , Membrana Dobles de Lípidos/química , Meliteno/química , Simulación de Dinámica Molecular , Fosfatidilcolinas/química , Imagen Individual de Molécula , Liposomas Unilamelares/químicaRESUMEN
OBJECTIVE: To compare and analyze the mental status of medical staff between Orthopedics Department who treated the victims in the earthquake and other surgical departments who did not treat the victims in the earthquake, and to provide evidence for psychological prevention and intervention in the earthquake aids. METHODS: Cross-sectional study was used to choose staff in the Orthopedics Department who treated the victims and other surgical departments who did not treat victims in the earthquake as eligible subject with convenient sampling. The research tool is Symptom Checklist-90. The questionnaire was done by participants with the same psychological instruction. Data were analyzed by SPSS16.0. RESULTS: The scores in somatization, depression,anxiety and opposition, phobic anxiety in the orthopedic staff were significantly higher than those of the other surgical staff (P < 0.05). CONCLUSION: There is disorder in mental health of medical staff in Orthopedics Department and mental intervention is needed.
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Terremotos , Cuerpo Médico/psicología , Trastornos por Estrés Postraumático/psicología , Adulto , China , Estudios Transversales , Femenino , Humanos , Masculino , Ortopedia , Escalas de Valoración Psiquiátrica , Encuestas y CuestionariosRESUMEN
A cheap, rapid and sensitive method for the determination of trace amount of lead in water samples by graphite furnace absorption spectrometry coupled with online flow injection preconcentration with ammonium pyrrolidine dithiocarboxylate chelating cellulose (CC-APDC) was developed. There were six steps in the preconcentration of flow injection: first, 0.15 mL nitric acid was used for a complete elution, which exceeded the volume of the graphite tube, so the 40 mL solution was removed before eluting. Secondly, 40 mL maximum concentration elution solution was added to GFAAS by fixed volume sampling to improve the accuracy. In addition, traditional stopping gas measurement was substituted with small flow gas atomization (30 mL x min(-1), preconcention for 1 min) during the removal of high memory effect for ashing stage in graphite furnace, which develops tail-out phenomenon and makes blank value low and steady. Various parameters affecting the adsorption and elution, such as pH of the solution, eluent concentration, sample flow rate etc, were optimized. If miniflow in atomization step was used, the memory effect in the determination of lead by GFAAS could be removed. The CC-APDC was used for preparation and preconcentration. A good precision (RSD = 1.4%, n = 10), high enrichment factor (15) and sample throughput (50 h) with detection limit 0.12 microg x L(-1) were obtained. This method has been successfully applied to the water sample for lead determination with a recovery of 95%-105%.
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Plomo/análisis , Espectrofotometría Atómica/métodos , Análisis de Inyección de Flujo , Grafito/química , Concentración de Iones de Hidrógeno , Pirrolidinas/química , Reproducibilidad de los Resultados , Tiocarbamatos/química , Contaminantes Químicos del Agua/análisisRESUMEN
Chelating cellulose is of simple preparation, excellent nature and low cost. MBM chelating cellulose (CC-MBM) was prepared with chelating reagent (2-mercaptobenzimidazole) grafted on cotton by indirect etherification method. The approach for separating and preconcentrating trace of Pb, Cd, Cu and Ni has advantages of high exchanging speed, high preconcentration multiple, high selectivity and easy elution. The sorption kinetic properties of CC-MBM for several heavy metal ions have also been studied systematically. It is shown that the sorption rate of CC-MBM is very rapid and the reaching time is short. The relation between the sorption amount and time completely complies with following equation Q/Q infinity = at/(1 + at).
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Bencimidazoles , Celulosa , Metales Pesados/química , Contaminantes Químicos del Agua/análisis , Adsorción , Quelantes , Matemática , Espectrofotometría Atómica/métodos , Espectroscopía Infrarroja por Transformada de Fourier , Purificación del Agua/métodosRESUMEN
In this study, we have demonstrated a facile one-step solvothermal method for the synthesis of the graphene nanosheet (GNS)/magnetite (Fe(3)O(4)) composite. During the solvothermal treatment, in situ conversion of FeCl(3) to Fe(3)O(4) and simultaneous reduction of graphene oxide (GO) into graphene in ethylene glycol solution were achieved. Electron microscopy study suggests the Fe(3)O(4) spheres with a size of about 200 nm are uniformly distributed and firmly anchored on the wrinkled graphene layers with a high density. The resulting GNS/Fe(3)O(4) composite shows extraordinary adsorption capacity and fast adsorption rates for removal of organic dye, methylene blue (MB), in water. The adsorption kinetics, isotherms and thermodynamics were investigated in detail to reveal that the kinetics and equilibrium adsorptions are well-described by pseudo-second-order kinetic and Langmuir isotherm model, respectively. The thermodynamic parameters reveal that the adsorption process is spontaneous and endothermic in nature. This study shows that the as-prepared GNS/Fe(3)O(4) composite could be utilized as an efficient, magnetically separable adsorbent for the environmental cleanup.
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Óxido Ferrosoférrico/química , Grafito/química , Azul de Metileno/química , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos , Adsorción , Cloruros/química , Restauración y Remediación Ambiental/métodos , Glicol de Etileno/química , Compuestos Férricos/química , Calor , Cinética , Microscopía Electrónica/métodos , Óxidos/química , Soluciones , Solventes/químicaRESUMEN
OBJECTIVE: To observe the efficacy of hydrogel dressings in preventing and treating vein injury of rabbits so as to provide a experimental evidence for clinical application. METHODS: Twenty-four healthy large-eared Japanese rabbits (48 ears) were chosen, weighing (2.15 +/- 0.15) kg, and divided into 3 groups randomly. The vein injury models were made by intravenously infusing 20% mannite (2.5 mL/kg). The sites of puncture were treated with hydrogel dressings (group A, n=8) and 25% MgSO4 (group B, n=8) 5 minutes after infusion. The sites of puncture were not treated as a blank control (group C, n=8). The tissue specimens were collected from the auricular veins at 24 hours after mannite infusion for histological observation by HE staining. The injury of the vessel wall, hemorrhage around the vessels, infiltration of inflammatory cells, and disturbance of circulation were observed to evaluate the injury degree of vein. RESULTS: There existed redness and congestion in the injured veins of each group. HE staining showed that in both groups A and B, the vessel wall was slightly injured and hemorrhage around the vessel was mild. There existed infiltration of inflammatory cells in the vessel wall and surrounding tissues. There also existed congestion and thrombus in the vessel lumen in these two groups. While in group C, the injury of vessel wall was severe, and schistic bleeding in the surrounding tissue of the vessel was existed. The severe congestion and thrombus in the vessel lumen was observed. There was no significant difference among three groups in the extent of vein wall injury and hemorrhage around the vessel (P > 0.05). The degree of infiltration of inflammatory cells and circulatory disturbance in both groups A and B were significantly less than that of group C (P < 0.05); but there was no significant difference between groups A and B (P > 0.05). CONCLUSION: Hydrogel dressing is helpful to prevent vein injury of rabbits induced by mannite.