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Introduction: Organophosphate compounds are often usedfor homicidal and suicidal purposes. It accounts for about80% of pesticide related hospital admissions. Study aimed toassess the severity of OP poisoning by POP scale, PSS andGCS and to compare POP scale, PSS and GCS in predictingthe treatment outcome in OP poisoning.Material and Methods: 100 patients of OP compoundpoisoning were included in the study. POP score, PSS andGCS were assessed at the time of presentation and weregrouped based on the severity. These scores were individuallyevaluated in predicting the ventilator requirement andmortality in OP compound poisoning and the scores werecompared with each other, as to asses which score was betterin predicting the severity of OP poisoning.Results: Ventilator requirement and mortality was found tobe in 43% and 16% of patients respectively. Intubation ratesand mortality rates were higher in patients with severe gradesof POP score, PSS and GCS with a significant p value (0.00),than in patients with mild to moderate grades. All three scorescorrelated well in predicting the requirement of ventilatorysupport and mortality in OP compound poisoning cases.Conclusion- The three scoring systems are simple andeffective tool that can be assessed based on the clinicalexamination. For a resource limited country, like India, any ofthe three scoring systems can be applied at the primary caresetting level which helps in making timely decision regardingneed for ventilatory support and timely shifting of patient tothe ICU care setting.
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Background: HIV illness and its related problems were significantly and positively correlated with both caregiver’s burden and caregiver’s adjustment. As there were limited studies on HIV caregiver’s stress, present study was conducted to estimate the magnitude and level of perceived stress among the predominant informal care giver of the PLHIV and to find out its correlates.Methods: This was a cross-sectional descriptive epidemiological study conducted on informal primary caregiver of PLHIV who was receiving ART since more than 2 months and attending the FIART centre of Bankura Sammilani Medical College and Hospital, Bankura between July 2018 to December 2018. PLHIV who were severely ill and informal caregivers having a psychological illness, disability, a severe form of chronic diseases except for HIV, were excluded. Data were collected using predesigned, pretested, semi-structured interviewer administered anonymous questionnaire including 10 points Sheldon Cohen’s perceived stress scale (PSS) following simple random sampling method. Multivariate logistic regression was done to find out the predictors of higher stress using SPSS software version 22.0.Results: Ultimately 108 caregivers were included. Mean score of PSS was 19.93±11.44 and score ranges from 0 to 40. In multivariate linear regression, it was found that caregiver who were belonging to lowest socio economic status were 3.9 times more perceive moderate to high stress than others. If HIV patients were suffering from other co-morbidities their primary caregiver perceived moderate to high stress 6.2 times more than others.Conclusions: Support group interaction among caregivers can alleviate the stress
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Background: Post graduate residents in tertiary care teaching hospitals in metropolitan cities bear the overwhelming burden due to heavy workload, they are at high risk of developing burnout syndrome, which in turn may affect hospital outcomes such as the quality and safety of the provided care.' This study was conducted to assess their perceived stress, stress induced somatic symptoms and coping strategies by postgraduates in Bangalore, India.Methods: This cross-sectional study was conducted on all postgraduates willing to participate in the study, pursuing their post-graduation in various specialties in Six medical colleges in Bangalore, India. Stress was assessed by Perceived stress scale (PSS-10), Stress induced physical symptoms using selected items from self-reporting questionnaire (SRQ-20), coping strategies using selected items from BRIEF COPE. Descriptive and inferential statistical analysis has been carried out in the present study.Results: The mean PSS score in present study was found to be 22.92 (moderate stress). Stress was associated with clinical specialty, higher workload, poor sleep quality due to more working hours, marital status, harmful ideations. In present study Post graduates of OBG, pediatrics, radiology demonstrated higher perceived stress score with a mean PSS Score of 25.57, 24.25, 24.22 respectively. Dermatology postgraduates reported lowest stress levels with a mean PSS score of 16.86.Conclusions: In present study post graduates are facing moderate stress, affecting their physical and mental health resulting in dysfunctional coping strategies and harmful ideations like quitting, which has an impact on quality and safety of provided care.
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Background: As adolescents are in transit from childhood to adulthood, they are vulnerable to stress and related complications. Measuring stress and its influencing factors is a prerequisite for developing strategy for this age-group. Objective of the study was to assess the level of perceived stress among school going late adolescents and to find out its predictors.Methods: This cross-sectional analytical epidemiological study was conducted among the school going Bengali late adolescents (15-17 years) of a rural block of West Bengal, India within July 2017 to December 2017. Finally, 102 students of class IX and XI were selected via two stage simple random sampling method. Data were collected by interview using pre-designed, pre-tested, semi structured questionnaire including 10 points Cohen’s perceived stress scale (PSS-10). Independent ‘t’ test, ANOVA, Mann Whitney U and Kruskal Wallis H test were utilized to establish the association between independent variables and PSS score. Independent variables found to be associated (p≤0.05) were considered in multiple linear regression to identify the predictors of stress.Results: Mean perceived stress score of participants were 16.8±3.7 (mean±2 SD) out of 40 (highest PSS score) with minimum and maximum score 8 and 26, respectively. In multiple linear regression, de-motivating comment, sibling pattern and love affair were found as predictors of stress perception among Bengali late adolescents. These factors collectively explained 15.6% variations of PSS score and individually contributed 3.8%, 5.6% and 6.2%, respectively.Conclusions: Stress can be alleviated by arranging motivational programme, counselling, and life skill education.
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Resumen Se exponen los resultados de un estudio sobre la emergencia de la capacidad de niños caminadores para resolver problemas, centrado en la manera como niños de 25 meses de edad acceden a la comprensión de un problema de compuertas, cuya solución les exige funcionamientos inferenciales distintos. Se aplicó una metodología microgenética, en la cual se utiliza una situación de resolución de problemas (SRP), en tres ensayos de una misma sesión de observación. El análisis se dirige a las variaciones interindividuales, a partir de las cuales se identifican tendencias en los desempeños de los niños. Los resultados ponen en evidencia la capacidad resolutoria de niños caminadores, manifestada en acciones sistemáticas, organizadas, automotivadas y en el uso de procesos inferenciales complejos.
Abstract The article presents the findings of a research on the emergence of toddlers' capacity to solve problems. The study focused on how 25-month-old children come to understand a safety gate problem, whose solution requires different inferential functions. A micro-genetic methodology was applied, using a problem-solving situation (PSS), in three trials during the same observation session. The analysis focused on inter-individual variations that allowed identifying tendencies in children's performance. The results are evidence of the problem-solving capacity of toddlers, expressed in systematic, organized, self-motivated actions and in the use of complex inferential processes.
Resumo Expõe-se os resultados de um estudo sobre a emergência da capacidade de crianças pequenas para resolver problemas, centrado na maneira como crianças de 25 meses de idade acessam à compreensão de um "problema de comportas", cuja solução lhes exige funcionamentos inferenciais distintos. Aplicou-se uma metodologia microgenética, na qual se utiliza uma situação de resolução de problemas (SRP), em três ensaios de uma mesma sessão de observação. A análise dirige-se às variações interindividuais, a partir das quais são identificadas tendências nos desempenhos das crianças. Os resultados evidenciam a capacidade resolutória de crianças pequenas, manifestada em ações sistemáticas, organizadas, automotivadas e no uso de processos inferenciais complexos.
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PURPOSE: This study examined the Poisoning Severity Score (PSS) from acute poisoning patients, to determine the relationships among the PSS, PSSsum, the primary outcome (prolonged stay at the ER over 24 hours, general ward and ICU admission and the application of intubation and mechanical ventilator, and the administration of inotropes). METHODS: A retrospective study was conducted through the EMR for 15 months. The PSS grade was classified according to the evidence of symptoms and signs. The differences in the primary outcomes between the PSS of when a single organ was damaged, and the PSS, PSSsum combined with the grade of when multiple organs were damaged, were studied. The cutoff value was calculated using the receiving operating characteristics (ROC) curve. RESULTS: Of the 284 patients; 85 (29.9%) were men with a mean age of 48.8 years, and their average arrival time to the ER was 4.4±6.7 hours. The most frequently used drug was hypnotics. The number of patients with PSS grade 0, 1, 2, 3, and 4 was 17, 129, 122, 24, and one, respectively. No ICU admissions, application of intubation and mechanical ventilators, administration of inotropes were observed among the patients with PSS grades 0 and 1 but only on patients with PSS grades 2 to 4. At PSS, when separating the patients according to the number of damaged organs, 17 had no symptoms, 133 had one organ damaged, 75 had two organs damaged, 36 had three organs damaged, and 23 had four organs damaged. Significant differences were observed between increasing number of damaged organs and the primary outcome. CONCLUSION: Among the acute poisoning patients, the PSS was higher in severity when the grade was higher. The number of damaged organs and the primary outcome showed meaningful statistical differences. This study confirmed that when the patients' PSS>2 and PSSsum>5, the frequency of ICU admission was higher, and they were considered to be severe with an increased prescription risk of application of intubation and mechanical ventilator, and the administration of inotropes.
Subject(s)
Humans , Male , Hypnotics and Sedatives , Intubation , Patients' Rooms , Poisoning , Prescriptions , Prognosis , Retrospective Studies , Ventilators, MechanicalABSTRACT
Background: Stress is a word very difficult to define. No one is stress-free nowadays. Stress has an impact on mental and physical wellbeing. Everyone has an ideal level of stress, but it differs from person to person. A certain amount of stress is necessary to perform at the optimum. If the stress is perceived as negligible or as exceeding one’s capacity to cope, then distress results. Stress among students of medical field (medical, dental and nursing) has gained more focus in recent years. Aim of the study: To assess the magnitude of stress among First-Year Nursing students of RMMCH, Annamalai University, Tamil Nadu. Materials and methods: The present study was a descriptive cross-sectional study. Data was collected using a proforma which included socio-demographic profile and PSS-14. Data were analyzed using SPSS software. Results: Study showed that 96% of students had stress. 94% of students had mild to moderate stress while 2% had severe stress. Conclusion: The prevalence of stress among Nursing students was high and there is a need for support services like stress management programs, relaxation techniques and so on. Support services may help to improve their ability to cope up with the demands of the course and also to have a stress free life.
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Introducción: El aumento de los niveles de estrés se convirtió en un problema para la salud de la población en general. Diferentes estudios demuestran que la realización de actividad física de manera regular disminuye la percepción de estrés psicológico en el individuo. Se sugiere que la relación entre actividad física y estrés psicológico percibido varía entre los dominios de la actividad física realizada y los diferentes grupos poblacionales. Objetivo: Establecer la asociación entre actividad física y estrés psicológico percibido en adultos residentes en barrios de estratos socioeconómicos 2 y 3 de Bucaramanga. Materiales y métodos: Se realizó un estudio observacional analítico de corte transversal en una población de 502 adultos residentes en la ciudad de Bucaramanga. Los participantes fueron entrevistados para obtener información acerca de la actividad física realizada y el nivel de estrés psicológico percibido. Además, se incluyeron en el estudio variables sociodemográficas y patrones de comportamiento. La información fue analizada mediante análisis bivariado y multivariado empleando modelos de regresión lineal múltiple y usando el programa STATA® 11.0. Resultados: Se determinó una asociación entre el cumplimiento de las recomendaciones de actividad física de la Organización Mundial de la Salud (OMS) y el puntaje de estrés psicológico percibido en los participantes (β = -1,90 IC 95 % -3,73 a -0,06; P = 0,043). Conclusiones: Cumplir con las recomendaciones de actividad física, se asoció con una disminución en el nivel de estrés psicológico en los participantes, quienes presentaron en promedio -1,9 puntos menos en el puntaje del PSS, que quienes no las cumplen.
Introduction: Increased stress levels became a problem for the general population's health. Research studies show that individuals engaging regular physical activity have a decreased perception of psychological stress. The relationship between physical activity and perceived psychological stress has been suggested to vary across domains of physical activity and across population groups. Objective: To establish the association between physical activity and perceived psychological stress in adults living in neighborhoods of the 2nd and 3rd socio-economic strata of Bucaramanga. Materials and methods: This observational analytical cross-sectional study was conducted in a population of 502 adult residents in the city of Bucaramanga. Individuals were interviewed to obtain information about physical activity and their level of perceived psychological stress. Data analysis will account for socio-demographic and behavior patterns using linear regression models, and it was performed in STATA® 11.0. Results: Meeting the physical activity recommendations was associated with a decrease in psychological stress levels in study participants (β = -1,90 IC 95 % -3,73 a -0,06; P = 0,043). Conclusions: Complying with the recommendations of physical activity was associated with a decrease in the psychological stress level in the participants, who had an average -1.9 points lower PSS score than those who do not comply.
Introdução: o aumento dos níveis de stress converteu-se em um problema para a saúde da população em geral. Diferentes estudos demonstrm que a realização de atividade física de maneira regular diminui a percepção de stress psicológico no indivíduo. Sugerese que a relação entre atividade física e stress psicológico percebido varia entre os domínios da atividade física realizada e os diferentes grupos populacionais. Objetivo: Estabelecer a associação entre atividade física e stress psicológico percebido em adultos residentes em bairros de estratos socioeconómicos 2 e 3 de Bucaramanga. Materiais e métodos: realizou-se um estudo observacional analítico de corte transversal, em uma população de 502 adultos residentes na cidade de Bucaramanga. Os participantes foram entrevistados para obter informações acerca da atividade física realizada e o nível de stress psicológico percebido. Além disso, incluíram-se no estudo variáveis sócio-demográficas e patrões de comportamento. A informação foi analisada mediante análise bivariada e multivariada empregando modelos de regressão lineal múltipla e, usando o programa STATA® 11.0. Resultados: se determinou uma associação entre o cumprimento das recomendações de atividade física da Organização Mundial da Saúde (OMS) e a pontuação de stress psicológico percebido nos participantes (β = -1,90 IC 95 % -3,73 a -0,06; P = 0,043). Conclusões: cumprir com as recomendações de atividade física, associou-se com uma diminuição no nível de stress psicológico nos participantes, quem apresentaram -1,9 pontos menos em média na pontuação do PSS, que quem não as cumprem.
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Humans , Stress, Psychological , Exercise , Causality , Surveys and Questionnaires , Colombia , Data AnalysisABSTRACT
Objective To observe the therapeutic efficacy of fire-needle acupuncture in treating benign prostatic hyperplasia. Method Sixty subjects were randomized into two groups by using the sealed envelope method. The control group was intervened by conventional medications; after classified into four syndrome types, down diffusion of damp-heat, liver qi stagnation, turbid stagnation and kidney qi deficiency, the treatment group was majorly treated with fire-needle acupuncture in addition to filiform-needle acupuncture. Fire-needle acupuncture was performed at Guanyuan (CV4), Qugu (CV2) and bilateral Dahe (KI12), once a week, for continuous 6 months; the filiform-needle acupuncture was majorly at Baihui (GV20) and Qihai (CV6) with adjunctive points modified according to different syndromes, twice a week, 8 sessions as a treatment course, for 5 courses in total. Result The improved rate was significantly higher in the treatment group than in the control group (P<0.05);the residual urine volume was significantly changed after the intervention in both groups (P<0.01), and the decrease in the treatment group was more significant than that in the control group (P<0.05). Conclusion Fire-needle acupuncture can improve the symptoms of benign prostatic hyperplasia and lower the residual urine volume.
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Este estudo teve como objetivos realizar a análise fatorial confirmatória da Escala de Estresse Percebido (Perceived Stress Scale - PSS), nas versões traduzidas de 14, 10 e 4 itens; analisar sua validade concorrente com o Questionário de Saúde Geral (QSG-12); mapear o perfil do estresse em uma amostra representativa da população; e estabelecer parâmetros de avaliação do estresse por meio da normatização dos escores da população total. A amostragem foi de base populacional, em formato de conglomerado por setores censitários. Participaram 1.154 habitantes de uma capital do Nordeste brasileiro, sendo a maioria do sexo feminino (55,6%), com nível de escolaridade em ensino médio (51,7%), empregados (72,7%) e não tabagistas (90,6%). As medianas de renda e idade ficaram em R$ 1.200,00 e 29 anos. Ao final, constatou-se que houve ajustes satisfatórios para as três versões da PSS apenas em seu modelo bifatorial e a escala com 10 itens se mostrou uma solução harmônica entre as versões completa e mais reduzida, considerando-se a relação entre a parcimônia na quantidade de itens e a robustez estatística deste instrumento. Ademais, a PSS ratificou sua validade concorrente com o QSG-12 e foi feita a normatização dos escores da PSS, estabelecendo-se parâmetros para comparação em futuros estudos.
This study aimed to perform a confirmatory factor analysis of the Perceived Stress Scale (PSS) in the Brazilian versions of 14, 10, 4 items; to analyze their concurrent validity with the General Health Questionnaire (GHQ-12); to map the profile of the stress in a representative sampling; and to establish stress assessment parameters by the standardization of the scores from overall population. The sample was population-based by conglomerate designs and clusters tracts. Thus, 1,154 inhabitants from a capital city of a northeastern state of Brazil participated in the study, mostly female (55.6%), with high school degree (51.7%), employed (72.7%), and nonsmokers (90.6%). The average income and age were BRL 1,200.00 and 29 years old, respectively. By the end, it was found satisfactory adjustments for the three PSS versions but just in its two-factor model; the PSS with 10 items was shown as a harmonious solution between the full and reduced scales considering the relationship between parsimony and statistical robustness of the scale. Furthermore, the PSS ratified its concurrent validity with the GHQ-12. It was also made the scores normalization of the PSS setting up parameters for future comparisons.
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Humans , Male , Female , Adolescent , Young Adult , Stress, Psychological/psychology , Factor Analysis, Statistical , PsychometricsABSTRACT
O presente estudo teve por objetivo investigar a dimensionalidade da Escala de Estresse Percebido em sua versão de 10 itens (PSS-10) em uma amostra de professores (N = 517). Uma análise fatorial exploratória pelo método de extração minimum rank factor analysis, utilizando a matriz de correlações policóricas e o critério de análise paralela para retenção dos fatores indicou a solução unifatorial como a mais ajustada aos dados. Os itens possuíram cargas fatoriais adequadas e o fator retido explicou 67% da variância comum dos escores, apresentando consistência interna (a = 0,80). Este estudo fornece evidências de validade da PSS-10 no contexto brasileiro.
The present study aimed to investigate the dimensionality of the 10-item Perceived Stress Scale (PSS-10) in a sample of school teachers (N = 517). An exploratory factor analysis done by the extraction method of minimum rank factor analysis, using polychoric correlation matrix and parallel analysis criterion for factor retention, indicated a one-factor solution as the best fit to the data. The items showed adequate factor loadings and the retained factor explained 67% of common scores variance, presenting internal consistency (a = .80). This study provides validity evidences of the PSS-10 for the Brazilian context.
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Humans , Male , Female , Adolescent , Young Adult , Middle Aged , Burnout, Professional/psychology , Faculty , Psychometrics , Education, Primary and SecondaryABSTRACT
Aims: The purpose of this study was to provide factorial analytic findings, construct validation and normative data for the Malaysian diabetic patients. Gender difference was also examined with racial response to PSS-10. Study design: Population base cross sectional survey. Place and Duration of Study: Penang between Nov 2009 and March 2010. Methodology: Cluster random sampling technique was employed for the selection participants in the community. A total of 1924 diabetic patients with age ≥ 18 (mean age = 39.51) were approached; 992 of them were female and 932 of them were male. People rated how often they had experienced these feelings in the last week on a five-point Likert scale from 0 = never to 4 = very often. The scale was translated into Malay language independently by two psychological counselors who had at least a master’s degree and bilingual efficiency. The LISREL 8.30 program was used to assenting factor analysis. Chisquare (χ 2)/df (degree of freedom) ratio, GFI (goodness of fit index), AGFI (adjusted goodness of fit index) and root mean square error of approximation (RMSEA) were used to evaluate the fit of the model (two-factor). Results: Barlett’s test of sphericity was 1603.417 (p<0.001) and Kaiser-Meyer-Olkin measure of the sampling adequacy was 0.83. Varimax rotation was conducted with these two identified factors. Factor A integrated items 1, 2, 3, 6, 9 and 10, labeled as ‘Perceived Avoidance’ while Factor B containing items 4, 5, 7, 8 and labeled as ‘Perceived Controllable’. Item variance showed 45.73 per cent of accountability with Factor A and 13.43 per cent with Factor B. Mandatory factor analysis for the two-factor of Malaysian version of PSS yielded: GFIs: χ 2 (39) = 127.846, p<0.001, χ 2/df= 4.1; GFI = 0.97; AGFI = 0.96; RMSEA = 0.06 and CFI = 0.99. Conclusion: PSS-10 is a reliable tool for assessing the stress measures among diabetic living of the society. High stress level is identified among the females as compared to male diabetic patients. Overall the whole cohort has high perceived stress level.
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El presente estudio tuvo como objetivo probar las cualidades psicométricas de las escalas PSS-Fa y PSS-Fr (Procidano & Heller, 1983), obteniendo su validez concurrente. El estudio se llevó a cabo en estudiantes mexicanos de nivel universitario con edades de 18 a 31 años. Se calcularon las correlaciones de las escalas de interés con otras variables teóricamente vinculadas al Apoyo Social Percibido como Estrés Percibido (PSS), Optimismo (LOT-R O), Pesimismo (LOT-R P), Estilos de Apego (RQ), Satisfacción en la Vida (SWLS), Número de la red de Apoyo y Satisfacción con la red de apoyo (SSQ6-N y SSQ6-S), Afecto Positivo y Negativo (PANAS-AP y AN), y Deseabilidad Social como variable de control (MC-SDS). También se realizaron comparaciones entre los extremos alto y bajo en apoyo social, y se encontraron diferencias significativas en algunas de las variables criterio. Se concluye que las escalas cuentan con evidencia empírica de su adecuada validez convergente y divergente y su poder discriminante para medir el apoyo social percibido.
The study aimed to test the psychometric qualities of PSS-Fa and PSS-Fr scales (Procidano & Heller, 1983), and their concurrent validity. The sample consisted of college Mexican students ranging from 18 to 31 years of age. In order to determine the concurrent validity, the scales were correlated with other psychological measures theoretically related to the construct of Perceived Social Support, such as Perceived Stress (PSS), Optimism (LOT-R O), Pessimism (LOT-R P), Attachment Styles (RQ), Life Satisfaction (SWLS), Number and Social Supporters Satisfaction (SSQ6-N & SSQ6-S), Positive and Negative Affect (PANAS-PA & NA), and Social Desirability (MCSDS) as a control variable. Finally, extreme (high and low) groups for perceived social support from family and friends were compared in each of the criteria variables and several significant differences were found. Both scales, PSS-Fa & PSS-Fr, were found to have adequate convergent and divergent validity and discriminant power to measure perceived social support.
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The patient with atopic dermatitis is often dissatisfied with the long-term nature of treatment for his/her disease. The aims of this study were to examine the effect of Kampo therapy on the skin manifestation of atopic dermatitis as well as the patient's mental state, and to evaluate the relation between severity of symptoms and satisfaction with the Kampo therapy. Kampo medicine was administered to 15 in-patients with atopic dermatitis for 6 months. Their clinical conditions, quality of life (QOL) assessments, and psychosomatic scores before and after treatment were observed and comparatively evaluated. We evaluated patients' symptom severity with the atopic dermatitis severity classifications of the Japanese Dermatological Association, and the European SCORAD (Scoring of Atopic Dermatitis). We evaluated QOL with the SF-36 and DLQI (Dermatology Life Quality Index), and mental state with the PSS-AD (Psychosomatic Scale for Atopic Dermatitis). Clinical conditions, QOL and mental states were improved after treatment with Kampo medicine. However, when we examined individual cases, severity of symptoms and satisfaction with treatment did not correlate. Patients' satisfaction ratings and the severity of their symptoms do not necessarily correspond in patients with atopic dermatitis, because evaluations vary with each individual. Therefore, clinicians treating patients for atopic dermatitis must make an effort to recognize each patient's psychological condition.
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Polymer-based organic light-emitting diodes (OLEDs) with the structure ITO / PEDOT:PSS / MDMO-PPV / Metal were prepared by spin coating. It is known that electroluminescence of these devices is strongly dependent on the material used as cathode and on the deposition parameters of the polymer electroluminescent layer MDMO-PPV. Objective. In this work the effect of i) the frequency of the spin coater (1000-8000 rpm), ii) the concentration of the MDMO-PPV: Toluene solution, and iii) the material used as cathode (Aluminium or Silver) on the electrical response of the devices, was evaluated through current-voltage (I-V) measurements. Materials and methods. PEDOT:PPS and MDMO-PPV organic layers were deposited by spin coating on ITO substrates, and the OLED structure was completed with cathodes of aluminium and silver. The electric response of the devices was evaluated based on the I-V characteristics. Results. Diodes prepared with thinner organic films allow higher currents at lower voltages; this can be achieved either by increasing the frequency of the spin coater or by using concentrations of MDMO-PPV: Toluene lower than 2% weight. A fit of the experimental data showed that the diodes have two contributions to the current. The first one is attributed to parasitic currents between anode and cathode, and the other one is a parallel current through the organic layer, in which the carrier injection mechanism is mediated by thermionic emission. Conclusions. The results of the fitting and the energy level alignment through the whole structure show that PPV-based OLEDs are unipolar devices, with current mainly attributed to hole transport.
Se fabricaron diodos orgánicos emisores de luz (OLEDs) con la estructura ITO / PEDOT:PSS / MDMO-PPV / Metal mediante la técnica de spin coating. Es ampliamente conocido que la electroluminiscencia de estos diodos depende fuertemente del material usado como cátodo y también de los parámetros de crecimiento de la capa del polímero electroluminiscente MDMO-PPV. Objetivo. En este trabajo el efecto de i) la frecuencia del spin coater (1000-8000 rpm), ii) la concentración de la solución MDMO-PPV: Tolueno y iii) el material usado como cátodo (plata o aluminio) sobre la repuesta eléctrica de los dispositivos, fue evaluado a través de medidas de corriente-voltaje (I-V). Materiales y métodos. Películas delgadas de los materiales orgánicos PEDOT:PSS y MDMO-PPV fueron depositados por spin coating sobre sustratos de ITO, y la estructura del OLED fue terminada con cátodo de plata y aluminio. La respuesta eléctrica de los dispositivos fue evaluada a través de su característica I-V. Resultados. Los diodos fabricados con películas orgánicas más delgadas son los que suministran mayores corrientes a menores voltajes. Esto puede lograrse ya sea incrementando la frecuencia de rotación del spin coating o usando concentraciones de MDMO-PPV: Tolueno menores al 2% en peso. Un ajuste de los datos experimentales demostró que los diodos poseen contribuciones de una corriente parásita entre ánodo y cátodo, y otra corriente paralela en donde el mecanismo predominante de inyección de portadores a la capa orgánica es a través de emisión termoiónica. Conclusiones. El ajuste de los datos experimentales, junto con la posición de niveles de energía a través de la heteroestructura, demuestra que los OLEDs basados en derivados de PPV son dispositivos unipolares, en el que la corriente se atribuye principalmente a transporte de huecos.
Foram fabricados diodos orgânicos emissores de luz (OLEDs) com a estrutura de ITO / PEDOT: PSS / MDMO-PPV / metal, pela técnica de spin coating. É amplamente conhecido que a eletroluminescência destes diodos depende fortemente do material utilizado como cátodo, e também dos parâmetros de crescimento da camada de polímero eletroluminescente MDMO-PPV. Objetivo. Neste trabalho o efeito de i) a freqüência do spin coater (1000-8000 rpm), ii) a concentração da solução MDMO-PPV: Tolueno e iii) o material utilizado como cátodo (prata ou alumínio) sobre a resposta elétrica dos dispositivos, foi avaliado por medidas de corrente-voltagem (I-V). Materiais e métodos. Películas finas de materiais orgânicos PEDOT: PSS e MDMO-PPV foram depositadas por spin coating sobre substratos de ITO e a estrutura do OLED foi terminada com cátodo de prata e de alumínio. A resposta elétrica dos dispositivos foi avaliada pela sua característica I-V. Resultados. Os diodos feitos de películas orgânicas finas fornecem maiores correntes a menores voltagens. Isto pode ser conseguido, quer através do aumento da velocidade de rotação do spin coating ou usando concentrações de MDMO-PPV: Tolueno menores de 2% em peso. Um ajuste dos dados experimentais mostrou que os diodos têm uma contribuição de uma corrente parasita entre anodo e catodo, e outra corrente paralela, onde o principal mecanismo da injeção de portadores da camada orgânica é através da emissão termiônica. Conclusões. O ajuste dos dados experimentais, juntamente com a posição dos níveis de energia através da heteroestrutura, mostra que os OLEDs baseados em derivados de PPV são dispositivos unipolares, onde a corrente é atribuída principalmente ao transporte de ocos.
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Objective To explore the neuroprotective role of propylene glycol alginate sodium sulfate(PSS) following cerebral ischemic reperfusion in rats.Methods Middle cerebral artery occlusion (MCAO) and reperfusion models were made using an intraluminal filament method.The rats in PSS treatment group were injected intraperitoneally with PSS(18.75 mg/kg) at 0,24 and 48 h after reperfusion,same quantity of normal saline was used in control group,sham-operation group and normal group.We studied neurological scores,infarct size,histological and ultrastructure changes of neurons and cell apoptosis.Results(1) The neurological score was(1.83?)0.75 in treatment group and(2.83?)0.75 in control group,the infarct size was((107.9?)12.1) mm~3 in treatment group and((150.3?)30.5)mm~3 in control group.The differences were significant between the two groups(all(P)0.05),and obviously decreased 6,12,24,48 and 72 h after reperfusion((P
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Objective To investigate the effects of polysaccharide sulfate(PSS)on the growth of vascular endothelial cell cultured in vitro and the adhesion of vascular endothelial cell to polymorphonuclear neutrophils(PMN).Methods ECV-304,a kind of human umbilical vein endothelial cells,was cultured in vitro with different concentrations of PSS(0,50,100,150,200,250 g?mL-1),the growth of ECV-304 was observed by means of MTT.Hypoxia/ reoxygenation(H/R) model of ECV-304 was established,the adhesion rate of PMN from patients with cerebral infarction to cultured ECV-304 was detected with or without treatment of PSS and H/R.Results The growth of ECV-304 in PSS-treated subgroups(final concentrations: 50,100,150,200 g?mL-1) were much better than in non-PSS subgroup,especially in subgroup with PSS final concentration of 100 g?mL-1.The adhesion rate of cultured ECV-304 to PMN from patients with cerebral infarction was higher significantly than that from the healthy subject,which was increased when ECV-304 being treated with H/R.The adhesion rate of cultured ECV-304(whether treated with H/R or not) to PMN was decreased significantly when ECV-304 being treated with PSS(100 g?mL-1).Conclusion The experiments in vitro showed that PSS could promote the growth of cultured ECV-304 and decrease the adhesion rate of H/R ECV-304 to PMN.
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Objective To observe the efficacy and safety of polysaccharide sulfate in treating patients with cold erythema multiforme.Methods Using polysaccharide sulfate,cetirizine and compound vitamin E ointment to treat 20 patients with cold erythema multiforme as the treatment group compared with the control group in which 20 patients with cold erythema multiforme were given cetirizine and compound vitamin E ointment.The course of treatment in 2 groups was 14 d.Results Forty patients were eligible for efficacy analysis(20 in each group).The total significant recovery rate was 95% for treatment group and 70% for control group,respectively;the therapeutic effects of the treatment group were better than those of the control group(P
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To explore the mechanism of protecting erythrocyte deformability (ED) of polysaccharide sulfate(PSS)and propyllene glycolmannurate sulfate(PGMS) in patients with acute myocardial infarction (AMI). The erythrocyte filtration index(EFI),erythrocgte membrane Na+,K+-ATPase .glutathione peroxidase(GSH-Px)activity and lipid peroxide(LPO) were measured in 52 patients with AMI. Meanwhile the effects of PSS and PGMS on EFI, Na+,K+-ATPase ,GSH-Px and LPO in AMI patients were observed in vitro. The results showed that the EFI and LPO were markedly higher ,Na+ ,K+-ATP ase and GSH-Px were si-hnificantly lower in patients than those in control(P0. 05). These results indicate that PSS and PGMS could improve the ED in patients ,and the efficacy of PSS or PGMS was related to enchancement of erythrocyte membrane ATP-ase anci GSH-Px activity.
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32 Cases of coronary heart diseases (M 20, F 12; age 58+10 y) were treated with polysacchairde sulfate (PSS). PSS 200 mg in 10% glucose solution 500 ml iv, drip, qd, and 14 d, as a course. The results showed; The cardiac function, blood fat and indices of hemorheology were significantly improved ( P