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Dried blood spot succinylacetone (SA) is often used as a biomarker for newborn screening (NBS) for tyrosinemia type 1 (TT1). However, false-positive SA results are often observed. Elevated SA may also be due to maleylacetoacetate isomerase deficiency (MAAI-D), which appears to be clinically insignificant. This study investigated whether urine organic acid (uOA) and quantitative urine maleic acid (Q-uMA) analyses can distinguish between TT1 and MAAI-D. We reevaluated/measured uOA (GC-MS) and/or Q-uMA (LC-MS/MS) in available urine samples of nine referred newborns (2 TT1, 7 false-positive), eight genetically confirmed MAAI-D children, and 66 controls. Maleic acid was elevated in uOA of 5/7 false-positive newborns and in the three available samples of confirmed MAAI-D children, but not in TT1 patients. Q-uMA ranged from not detectable to 1.16 mmol/mol creatinine in controls (n = 66) and from 0.95 to 192.06 mmol/mol creatinine in false-positive newborns and MAAI-D children (n = 10). MAAI-D was genetically confirmed in 4/7 false-positive newborns, all with elevated Q-uMA, and rejected in the two newborns with normal Q-uMA. No sample was available for genetic analysis of the last false-positive infant with elevated Q-uMA. Our study shows that MAAI-D is a recognizable cause of false-positive TT1 NBS results. Elevated urine maleic acid excretion seems highly effective in discriminating MAAI-D from TT1.
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Tirosinemias , Humanos , Recién Nacido , Biomarcadores , Cromatografía Liquida , Creatinina , Tamizaje Neonatal/métodos , Espectrometría de Masas en Tándem , Tirosinemias/diagnósticoRESUMEN
Given the high prevalence and severe consequences of childhood sexual abuse, it is essential to identify ways to support adult survivors. One potential and relatively unexplored resource available to survivors is the human-pet relationship. In the literature, the human-pet relationship is linked to many positive benefits to physiological regulation, mental health, physical health, and social support - areas of functioning where survivors of childhood sexual abuse may be particularly at risk. Despite existing evidence, there is little research on human-pet relationships among survivors of childhood sexual abuse. To help address this gap, this qualitative study explored the lived experience of human-pet relationships among adult survivors of childhood sexual abuse. Utilizing data collection and analysis methods from Interpretative Phenomenological Analysis, semi-structured interviews were conducted with 10 adult survivors of childhood sexual abuse. The following themes were developed from the data: (a) close bond with pet; (b) idiosyncrasies within the human-pet relationship; (c) moral responsibility; (d) fundamental differences between pets and humans; (e) safety in the human-pet relationship; (f) resource for coping with painful experience; (g) positive impact on well-being; (h) buttress for human-human social interaction; (i) medium for skill and knowledge development; and (j) shortcomings of the human-pet relationship. Findings are discussed in the context of the existing literature, along with considerations for practice and future research with childhood sexual abuse survivors.
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Abuso Sexual Infantil , Adulto , Niño , Humanos , Sobrevivientes , Adaptación Psicológica , Investigación CualitativaRESUMEN
BACKGROUND: Mental illness is among the most common causes of morbidity, mortality, and disability in childhood. Mindfulness-based stress reduction (MBSR) has shown significant benefit in mental health; however, evidence of its effectiveness in youth is limited. The objective of this study was to compare the efficacy of MBSR plus usual care versus usual care alone for reducing mental health symptoms in youth. METHODS: A two-arm, mixed methods, randomized cluster-controlled trial of 12-18 year olds who were residents of CASA House, a voluntary residential treatment program for adolescents, between January 2011 and March 2013 (clinicaltrials.gov, NCT01307943). INTERVENTIONS: Treatment terms were randomized to usual care, or MBSR plus usual care, which included eight MBSR sessions of 2 hr/week. OUTCOMES: The primary outcome was impact on emotions and behavior at the end of the program, using the Behavior Assessment System for Children, Second Edition (BASC-2). Secondary outcomes included perceived stress levels, mindfulness, and emotional regulation. RESULTS: A total of 85 participants were randomized to either the MBSR arm (n = 45) or control arm (n = 40). Significant differences in favor of MBSR were found on Teacher ratings of the Internalizing Problems (p = .038) and Adaptive Skills subscales (p = .022) on the BASC-2. No significant differences were found on other outcomes. A post hoc analysis found that the MBSR arm had a significantly shorter time to discharge (p = .02). CONCLUSION: The results of this study indicate that MBSR is effective for improved coping with internalizing problems and adaptive emotional skills in our sample. Future studies should focus on larger, longer-term studies in youth.
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BACKGROUND: While studies on mindfulness-based stress reduction (MBSR) for youth have recently emerged, there is a shortage of research on how adolescents from clinical populations experience MBSR. The purpose of this qualitative study was to explore the impact of MBSR from the subjective perspective of adolescents with serious mental health concerns. METHOD: Adolescents (n = 28) from a residential treatment center participated in an adapted 8-week MBSR program in which they learned a range of mindfulness skills and were encouraged to apply the skills to their everyday lives. At the end of the program and at a 3-month follow-up, the youth participated in semistructured interviews in which they were asked to describe the impact of the program from their perspectives. Basic interpretive qualitative analysis methods were used to code the data and to group the codes into higher level themes. RESULTS: Six main themes were found, including improved mood, enhanced relationship to self, increased self-control, improved problem-solving, awareness of the present, and enhanced interpersonal relationships. DISCUSSION: Results from this study suggest that the MBSR program was perceived as beneficial both in the short-term and follow-up in several aspects of emotional, cognitive, and interpersonal functioning.
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Vascular endothelial cells are known to respond to a range of biochemical and time-varying mechanical cues that can promote blood vessel sprouting termed angiogenesis. It is less understood how these cells respond to sustained (i.e., static) mechanical cues such as the deformation generated by other contractile vascular cells, cues which can change with age and disease state. Here we demonstrate that static tensile strain of 10%, consistent with that exerted by contractile microvascular pericytes, can directly and rapidly induce cell cycle re-entry in growth-arrested microvascular endothelial cell monolayers. S-phase entry in response to this strain correlates with absence of nuclear p27, a cyclin-dependent kinase inhibitor. Furthermore, this modest strain promotes sprouting of endothelial cells, suggesting a novel mechanical 'angiogenic switch'. These findings suggest that static tensile strain can directly stimulate pathological angiogenesis, implying that pericyte absence or death is not necessarily required of endothelial cell re-activation.
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Ciclo Celular , Células Endoteliales/fisiología , Neovascularización Fisiológica , Pericitos/fisiología , Resistencia a la Tracción , Animales , Fenómenos Biomecánicos , Humanos , Estrés MecánicoRESUMEN
Water within pores of cementitious materials plays a crucial role in the damage processes of cement pastes, particularly in the binding material comprising calcium-silicate-hydrates (C-S-H). Here, we employed Grand Canonical Monte Carlo simulations to investigate the properties of water confined at ambient temperature within and between C-S-H nanoparticles or "grains" as a function of the relative humidity (%RH). We address the effect of water on the cohesion of cement pastes by computing fluid internal pressures within and between grains as a function of %RH and intergranular separation distance, from 1 to 10 Å. We found that, within a C-S-H grain and between C-S-H grains, pores are completely filled with water for %RH larger than 20%. While the cohesion of the cement paste is mainly driven by the calcium ions in the C-S-H, water facilitates a disjoining behavior inside a C-S-H grain. Between C-S-H grains, confined water diminishes or enhances the cohesion of the material depending on the intergranular distance. At very low %RH, the loss of water increases the cohesion within a C-S-H grain and reduces the cohesion between C-S-H grains. These findings provide insights into the behavior of C-S-H in dry or high-temperature environments, with a loss of cohesion between C-S-H grains due to the loss of water content. Such quantification provides the necessary baseline to understand cement paste damaging upon extreme thermal, mechanical, and salt-rich environments.
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Adolescence is a critical time of physiological, cognitive, and social development. It is also a time of increased risk-taking and vulnerability for psychopathology. White matter (WM) changes during adolescence have been better elucidated in the last decade, but how WM is impacted by psychopathology during this time remains unclear. Here, we examined the link between WM microstructure and psychopathology during adolescence. Twenty youth diagnosed with affective, attentional, and behavioral disorders (clinical sample), and 20 age-matched controls were recruited to examine group differences in WM microstructure, attentional control, and the link between them. The main results showed that clinical sample had relatively lower attentional control and fractional anisotropy (FA) in WM throughout the brain: two association tracts were identified, and many differences were found in areas rich in callosal and projection fibers. Moreover, increased FA was positively associated with attention performance in the clinical sample in structures supporting ventral WM pathways, whereas a similar link was identified in controls in dorsal WM association fibers. Overall, these results support a model of general impairment in WM microstructure combined with reliance on altered, perhaps less efficient, pathways for attentional control in youth with affective, attentional, and behavioral disorders.
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Atención/fisiología , Sustancia Blanca/patología , Adolescente , Anisotropía , Encéfalo/patología , Cognición/fisiología , Imagen de Difusión Tensora/métodos , Femenino , Humanos , Masculino , Trastornos Mentales/patologíaRESUMEN
OBJECTIVES: While attributions have been found to play an important role in the experience of shame, little is currently known about attributions that occur as part of shame reparation. This exploratory study investigated the attributions associated with recovery from shame, based on the perspectives of participants. DESIGN: Grounded theory was used in data collection and analysis. This approach has been used extensively for developing understandings of how people construct meaning, interpret events, and act on the basis of their beliefs and interpretations. METHODS: The participants were nine women and four men between the ages of 24 and 70. Data came from interviews in which the participants recalled a distressing shame experience and described how they recovered. Emphasis was on the participants' subjective perspectives, meanings, and interpretations. RESULTS: Shame involved global and stable dispositional attributions where the entire self was regarded as flawed and unattractive, and participants perceived themselves as powerless to change an unwanted identity. Internal causal attributions and self-blame were present in most but not all shame experiences. Recovery involved a movement towards specific and unstable attributions that enhanced self-concept and maximized a sense of power and control over the future. Shared and external factors that contributed to the event were also identified. CONCLUSIONS: When applied to psychotherapy for shame-related distress, these findings point to the importance of exploring clients' attributions related to specific shame events and using interventions that promote attributional change. Directions for further research are discussed.
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Adaptación Psicológica , Acontecimientos que Cambian la Vida , Autoimagen , Vergüenza , Adulto , Anciano , Femenino , Humanos , Control Interno-Externo , Masculino , Persona de Mediana Edad , Modelos Psicológicos , Inventario de Personalidad , Psicoterapia , Investigación Cualitativa , Identificación Social , Percepción Social , Estrés Psicológico/psicologíaRESUMEN
BACKGROUND AND PURPOSE: Several methodological challenges are associated with measuring resilience in women. This study compares the 14-item Resilience Scale (RS-14) and the Resilience Scale for Adults (RSA) in a community sample of women. METHODS: Data were collected from 120 women residing in low socioeconomic areas of Karachi, Pakistan. Construct validity, internal consistency, and responsiveness were calculated. RESULTS: Both scales demonstrated satisfactory psychometric characteristics. The total RS-14 score was significantly associated with all subscales of the RSA. However, two items of the RS-14 did not show any association with any of the subscales of the RSA. Medium effect size was noted on the "structured style"subscale of the RSA. CONCLUSION: Differences between the scales concluded that the Urdu version the of RSA yielded improved results in this sample.
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Psicometría , Resiliencia Psicológica , Salud de la Mujer , Adulto , Femenino , Humanos , Lenguaje , Persona de Mediana Edad , Pakistán , Reproducibilidad de los Resultados , Adulto JovenRESUMEN
OBJECTIVES: This study tested the efficacy of a 6-week social support intervention for enhancing resilience and quality of life among women living in low socioeconomic areas of Karachi, Pakistan. METHODS: One hundred and twenty women were randomly allocated to the intervention (n = 60) or control group (n = 60). Women in the intervention group attended a 6-week social support program, while those in the control group attended a single mental health awareness session. Outcome variables were measured via the resilience scale-14 item (RS-14), the resilience scale for adults (RSA), and World Health Organization quality of life brief scale (WHOQOL-BREF). RESULTS: Compared to participants in the control group, women in the intervention group reported improvements in resilience measured by RS-14 (p = 0.022) and the structured style subscale of the RSA (p = 0.043). A medium effect size was also measured on the structured style subscale (d = 0.6, 95% CI = 0.62874, 2.57126). No significant findings were noted on QOL scores. CONCLUSIONS: Community-based social support interventions are a gender-sensitive-, culturally appropriate-, and resource-sparing approach to promote women's resilience and improve their mental health.
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Promoción de la Salud/métodos , Calidad de Vida , Resiliencia Psicológica , Apoyo Social , Adulto , Femenino , Humanos , Persona de Mediana Edad , Pakistán , Áreas de Pobreza , Evaluación de Programas y Proyectos de Salud , Adulto JovenRESUMEN
BACKGROUND: American studies have shown positive effects of Blood Glucose Awareness Training (BGAT) on the recognition of hypoglycaemia. We evaluated the effects of BGAT among Dutch patients, and compared individual training with training in the original group format. METHODS: Fifty-nine type 1 diabetes patients participated in BGAT in either a group (n = 37) or an individual (n = 22) setting. Before and one year after training they performed up to 70 measurements, two to four a day, at home on a handheld computer. During each measurement they estimated their blood glucose (BG), indicated whether they would be participating in traffic and raised their BG on the basis of their estimation, and then measured their BG. The incidence of severe hypoglycaemia and traffic accidents was also assessed. RESULTS: BGAT had positive effects on hypoglycaemic awareness, decisions not to drive and to raise the blood glucose during hypoglycaemia, severe hypoglycaemic episodes and traffic accidents. The accuracy of BG estimations only improved after group training, while after individual training patients tended to measure more or more extremely high BG values. CONCLUSION: The training improved awareness of hypoglycaemia, and seems worthy of implementation in The Netherlands.
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Concienciación , Diabetes Mellitus Tipo 1/psicología , Educación del Paciente como Asunto , Adulto , Análisis de Varianza , Glucemia/metabolismo , Automonitorización de la Glucosa Sanguínea , Cromatografía Líquida de Alta Presión , Diabetes Mellitus Tipo 1/sangre , Femenino , Estudios de Seguimiento , Humanos , Hipoglucemia/sangre , Hipoglucemia/prevención & control , Hipoglucemia/psicología , MasculinoRESUMEN
A sensitive and reproducible flow cytometric assay was developed for the analysis of Fc gamma and C3b(i) receptors on HSV-infected cells. The method is based on a rosette technique using fluorochrome-labeled erythrocytes sensitized with IgG or C3b(i). A comparison of flow cytometric and microscopic quantitation demonstrated that the binding of EIgG, EC3b(i) to HSV-infected cells were correlated. Flow cytometric analysis provides the opportunity to study simultaneously the distribution of E per HSV-infected cell and the total binding of E to the whole population of HSV-infected cells. Receptor activity and HSV glycoprotein cell surface expression were shown to be correlated in a linear fashion. The assay could be applied to other Fc gamma R- and C3b(i)R-bearing cells.
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Citometría de Flujo , Herpes Simple/inmunología , Receptores de Complemento 3b/análisis , Receptores Fc/análisis , Formación de Roseta , Animales , Glicoproteínas/análisis , Humanos , Ratones , Microscopía , Ovinos , Proteínas Virales/análisisRESUMEN
The results are presented from a case-control study, concerning the possible relation between silica exposure in the Dutch fine ceramic industry and lung cancer. For this purpose 381 male, age-matched pairs of primary lung cancer cases and controls were selected from the pathology department of the University Hospital in the region, where two large ceramic companies are located. Information about employment in the ceramic industry was obtained from the personnel and financial administration departments of the two companies. On the basis of job titles a panel of occupational hygiene experts reached consensus about the qualitative exposures of each individual worker. Twenty one per cent of the cases were employed in the ceramic industry, compared with 19% of the controls (odds ratio 1.11; 95% Cl: 0.77-1.61). Although the average employment period of cases and their relative silica exposure surpassed those of controls, odds ratios for long duration of employment and considerable exposure to respirable silica dust did not reach statistical significance. After constructing a qualitative exposure index, based on the amount and duration of exposure, a tendency towards a positive correlation with lung cancer emerged. No relation between specific histological tumour cell types and working in the ceramic industry emerged. Although the study does not suggest a consistent cause-effect relation between silica exposure in the regional, Dutch fine ceramic industry and lung cancer, an increased risk for the high exposure group in the past can not be totally excluded.
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Adenocarcinoma/epidemiología , Carcinoma de Células Escamosas/epidemiología , Carcinoma/epidemiología , Neoplasias Pulmonares/epidemiología , Dióxido de Silicio/efectos adversos , Adenocarcinoma/etiología , Adenocarcinoma/mortalidad , Adulto , Anciano , Carcinoma/etiología , Carcinoma/mortalidad , Carcinoma de Células Escamosas/etiología , Carcinoma de Células Escamosas/mortalidad , Estudios de Casos y Controles , Causalidad , Causas de Muerte , Exposición a Riesgos Ambientales , Femenino , Humanos , Neoplasias Pulmonares/etiología , Neoplasias Pulmonares/mortalidad , Masculino , Persona de Mediana Edad , Países Bajos , RegistrosRESUMEN
A cross-sectional analysis of the relation between the estimated healthy worker effect (HWE), as measured by a total Standardized Mortality Ratio (SMR) less than 100, and relevant design characteristics in 270 published retrospective occupational cohort studies is presented. The majority of the reviewed studies showed a HWE, varying in SMR from 50 to 99 (mean: 84). The estimated HWE seemed to influence the final outcomes of the studies to a great extent. A tendency for a positive relation between the study size in terms of the number of exposed workers, total number of person-years of follow-up, and the HWE emerged. Studies with a comparatively short follow-up period had an increased chance of resulting in a HWE. Cross-sectional cohorts did not show a stronger HWE than open cohorts. Studies of chemical exposures revealed a fivefold excess of having a HWE compared with other studies.
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Efecto del Trabajador Sano , Enfermedades Profesionales/mortalidad , Proyectos de Investigación/normas , Estudios de Cohortes , Estudios Transversales , Humanos , Modelos Logísticos , Valores de Referencia , Estudios RetrospectivosRESUMEN
Herpes simplex virus type-1 (HSV-1) induces Fc- and C3b(i)-receptors on infected cells. The role of these receptors in bacterial superinfection was studied by comparing the adherence of non-opsonised and opsonised bacteria to HSV-infected and non-infected HEp-2 cells. A flow cytometric adherence assay, based on the fluorescent quantitation of FITC-labelled bacteria, was developed. Opsonisation of Staphylococcus epidermidis with human serum, resulted in a marked increase in adherence to HSV-infected cells and revealed a role for C3b(i)R- and FcR-mediated adhesion. However, the enhanced adherence never exceeded the level of attachment to non-infected cells. Increased adherence of other pathogenic bacteria, including Escherichia coli, Streptococcus pneumoniae, Haemophilus influenzae and Pseudomonas aeruginosa was not observed, indicating that the HSV-receptors play a minor role in secondary infections. Bacterial adhesion factors such as the fimbriae of E. coli played a more dominant role in the adherence of bacteria to HSV-infected cells.
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Bacterias/metabolismo , Adhesión Bacteriana/inmunología , Herpesvirus Humano 1/fisiología , Receptores de Complemento 3b/fisiología , Receptores Fc/fisiología , Adulto , Anticuerpos Monoclonales/inmunología , Bacterias/inmunología , Unión Competitiva , Línea Celular , Escherichia coli/inmunología , Escherichia coli/metabolismo , Fimbrias Bacterianas , Citometría de Flujo , Haemophilus influenzae/inmunología , Haemophilus influenzae/metabolismo , Herpesvirus Humano 1/inmunología , Humanos , Sueros Inmunes/inmunología , Inmunoglobulina G/inmunología , Proteínas Opsoninas/inmunología , Pseudomonas aeruginosa/inmunología , Pseudomonas aeruginosa/metabolismo , Staphylococcus epidermidis/inmunología , Staphylococcus epidermidis/metabolismo , Streptococcus pneumoniae/inmunología , Streptococcus pneumoniae/metabolismoRESUMEN
Gender inequalities in health are a consequence of the basic inequality between men and women in many societies. Despite the importance of socio-economic factors, women's health is also greatly affected by the extent and quality of health services available to them. Both non-governmental women's organizations and feminist health researchers have in recent years identified major gender inequalities in access to services and in the way men and women are treated by the health care system. Firstly, although women are major health care users as well as providers, they are under-represented in decision-making in health care. Secondly, no justice is done in general to existing differences in position and needs of women and men in defining quality of health care, i.e. gender aspects. Among women's organizations, there is general agreement that "gender sensitive health care should be available, accessible, affordable, appropriate and acceptable". In addition, health care for women should be adequate and not depart from a male model of health and illness. In this paper, we pay attention to inappropriate health care for women on the one hand, as illustrated by the increasing medicalization of women's reproductive life [menstruation, menopause, pregnancy and childbirth and (in)fertility]. On the other hand, we discuss gender bias in the management of serious, life-threatening diseases such as cardiovascular disease, lung cancer, and kidney failure, as a form of inadequate care. These examples are followed by a global vision on quality of care from a gender perspective, as formulated by the women's health care movement in the Netherlands and at the Fourth International Conference on Women in Beijing. If anything, the recommendations agreed upon in Beijing will have to ensure the consolidation and enhancement of good quality health care for women around the world. The final discussion, attempts to give some general recommendations for achieving more adequate (gender sensitive) and appropriate (non-medicalizing) health care for women. These recommendations pertain to health and health care research, policy, education, and organization from a women's perspective.
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Calidad de la Atención de Salud , Servicios de Salud para Mujeres/normas , Femenino , Accesibilidad a los Servicios de Salud , Humanos , Pautas de la Práctica en Medicina , Embarazo , Prejuicio , Derechos de la MujerRESUMEN
The aim of this study was to explore sex differences in illness beliefs and behavior in patients with suspected coronary artery disease (CAD). Twenty-eight patients, 16 women and 12 men, were interviewed. The results show that both men and women think of CAD as a 'men's disease' and have equal knowledge of CAD risk factors. However, especially the men considered their own risk of developing CAD lower than their estimated probability of their own sex and as low as their estimated risk for women. Both men and women did not attribute their symptoms indicative of CAD to their heart. Women, especially those who did not attribute their symptoms to their heart, had a longer patient delay than men, although their symptoms were indicative of CAD. To conclude, men as well as women should be made more aware of their own risk of developing CAD and of the manifestation of CAD symptoms. Physicians could be encouraged to ask patients more explicitly and thoroughly about their illness beliefs, to check their knowledge and inform them about CAD.
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Actitud Frente a la Salud , Enfermedad Coronaria/psicología , Conocimientos, Actitudes y Práctica en Salud , Hombres/psicología , Rol del Enfermo , Mujeres/psicología , Enfermedad Coronaria/diagnóstico , Medicina Familiar y Comunitaria , Femenino , Humanos , Masculino , Persona de Mediana Edad , Encuestas y CuestionariosRESUMEN
Medically unexplained (gynecological) symptoms can be viewed as an indication of the somatization of negative emotions. Most studies regarding psychological correlates of medically unexplained gynecological symptoms have paid attention only to certain personality characteristics of women with these symptoms. In this study the reporting of physical symptoms and the resulting illness behavior is explained in terms of information processing or a perception process, i.e. the process by which people detect and interpret physical sensations as symptoms of illness (symptom perception). Symptom perception is in part determined by environmental characteristics and cognitive and emotional processes, such as variation in daily life, (coping with) emotional threat and the use of cognitive illness schemes. Differences in symptom perception and illness behavior of women with medically unexplained and explained gynecological symptoms, compared to women with medically explained gynecological symptoms and a control group, were established with the help of a questionnaire, containing a number of scales. As expected, women with medically unexplained gynecological symptoms had higher reports of common symptoms and sensations and showed also more other illness behavior than the other two groups. They reported less variation and more threat in daily life than the other two groups. These variables together with the use of illness schemes contributed most to symptom reporting of women with medically unexplained symptoms. It is concluded that defence against threat is probably an important determinant. Suggestions for further research and some practical implications are discussed.
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Actitud Frente a la Salud , Enfermedades de los Genitales Femeninos/psicología , Trastornos Psicofisiológicos/psicología , Rol del Enfermo , Adolescente , Adulto , Anciano , Mecanismos de Defensa , Femenino , Enfermedades de los Genitales Femeninos/diagnóstico , Enfermedades de los Genitales Femeninos/fisiopatología , Humanos , Procesos Mentales , Persona de Mediana Edad , Modelos Psicológicos , Trastornos Psicofisiológicos/diagnóstico , Trastornos Psicofisiológicos/fisiopatología , Encuestas y CuestionariosRESUMEN
Despite its ubiquitous presence in the built environment, concrete's molecular-level properties are only recently being explored using experimental and simulation studies. Increasing societal concerns about concrete's environmental footprint have provided strong motivation to develop new concrete with greater specific stiffness or strength (for structures with less material). Herein, a combinatorial approach is described to optimize properties of cement hydrates. The method entails screening a computationally generated database of atomic structures of calcium-silicate-hydrate, the binding phase of concrete, against a set of three defect attributes: calcium-to-silicon ratio as compositional index and two correlation distances describing medium-range silicon-oxygen and calcium-oxygen environments. Although structural and mechanical properties correlate well with calcium-to-silicon ratio, the cross-correlation between all three defect attributes reveals an indentation modulus-to-hardness ratio extremum, analogous to identifying optimum network connectivity in glass rheology. We also comment on implications of the present findings for a novel route to optimize the nanoscale mechanical properties of cement hydrate.
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BACKGROUND: Gastrointestinal bleeding in infants and children is a potentially serious condition in the practice of general pediatrics that requires investigation. The objective of this study is to describe the endoscopic and histopathological findings in children with upper gastrointestinal (UGI) bleeding of non variceal origin. PATIENTS AND METHODS: We performed a retrospective study of the medical records of 181 children, aged 1 month to 15.2 years, with non variceal UGI bleeding, who were admitted in our department over the period 1988-2008 and underwent upper GI endoscopy accompanied by histology. Patients were divided in 4 groups according to their age (=0-1 years, = 1-6 years, C=6-12 years, D= 12-16 years). RESULTS: An endoscopically evident bleeding source was detected in only 5% of all patients. Histological examination revealed increased incidence of eosinophilic infiltration in infants, in contrast to all other age groups, where non-specific or H. pylori related inflammation predominated. Peptic ulcer was found in 4.4% of all patients. CONCLUSION: Although an evident bleeding source was detected in only a small percentage of patients, the accompanying histological examination provided additional information regarding possible underlying diseases and contributed to the subsequent therapeutic management.