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1.
Small Bus Econ (Dordr) ; : 1-25, 2023 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38625186

RESUMEN

The remarkable ascent of entrepreneurship witnessed as a scientific field over the last 4 decades has been made possible by entrepreneurship's ability to absorb theories, paradigms, and methods from other fields such as economics, psychology, sociology, geography, and even biology. The respectability of entrepreneurship as an academic discipline is now evidenced by many other fields starting to borrow from the entrepreneurship view. In the present paper, seven examples are given from this "pay back" development. These examples were first presented during a seminar at the Erasmus Entrepreneurship Event called what has the entrepreneurship view to offer to other academic fields? This article elaborates on the core ideas of these presentations and focuses on the overarching question of how entrepreneurship research impacts the development of other academic fields. We found that entrepreneurship research questions the core assumptions of other academic fields and provides new insights into the antecedents, mechanisms, and consequences of their respective core phenomena. Moreover, entrepreneurship research helps to legitimize other academic fields both practically and academically.


Entrepreneurship research questions the core assumptions of other academic fields and legitimizes them both practically and academically. Since the 1980s, entrepreneurship research has seen tremendous growth and development, establishing itself as an academic field. Entrepreneurship is also taught extensively in leading business schools around the world. Indeed, few business schools do not address entrepreneurship in their curriculum. This represents a sea change: although entrepreneurs and new ventures had a remarkable impact on society, academia barely noticed it in the 1980s. Simply put: economics and business students rarely, if ever, encountered any mention of entrepreneurship during their studies. While entrepreneurship research has now developed its own methodological toolbox, it has extensively borrowed perspectives, theories, and methods from other fields. In the 2020s, we now find that entrepreneurship scholars are sharing its toolbox with other academic fields, questioning the core assumptions of other academic fields and providing new insights into the antecedents, mechanisms, and consequences of their respective core phenomena. Moreover, entrepreneurship research helps to legitimize other academic fields both practically and academically. Hence, entrepreneurship research now plays not just an important role in entrepreneurship education, practice, and policy but also throughout many other research fields.

2.
PLoS Genet ; 13(1): e1006495, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28095416

RESUMEN

Large-scale genome-wide association results are typically obtained from a fixed-effects meta-analysis of GWAS summary statistics from multiple studies spanning different regions and/or time periods. This approach averages the estimated effects of genetic variants across studies. In case genetic effects are heterogeneous across studies, the statistical power of a GWAS and the predictive accuracy of polygenic scores are attenuated, contributing to the so-called 'missing heritability'. Here, we describe the online Meta-GWAS Accuracy and Power (MetaGAP) calculator (available at www.devlaming.eu) which quantifies this attenuation based on a novel multi-study framework. By means of simulation studies, we show that under a wide range of genetic architectures, the statistical power and predictive accuracy provided by this calculator are accurate. We compare the predictions from the MetaGAP calculator with actual results obtained in the GWAS literature. Specifically, we use genomic-relatedness-matrix restricted maximum likelihood to estimate the SNP heritability and cross-study genetic correlation of height, BMI, years of education, and self-rated health in three large samples. These estimates are used as input parameters for the MetaGAP calculator. Results from the calculator suggest that cross-study heterogeneity has led to attenuation of statistical power and predictive accuracy in recent large-scale GWAS efforts on these traits (e.g., for years of education, we estimate a relative loss of 51-62% in the number of genome-wide significant loci and a relative loss in polygenic score R2 of 36-38%). Hence, cross-study heterogeneity contributes to the missing heritability.


Asunto(s)
Exactitud de los Datos , Estudio de Asociación del Genoma Completo/normas , Programas Informáticos , Estudio de Asociación del Genoma Completo/métodos , Humanos , Metaanálisis como Asunto
3.
Health Econ ; 24(10): 1302-1313, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25048640

RESUMEN

The self-employed are often reported to be healthier than wageworkers; however, the cause of this health difference is largely unknown. The longitudinal nature of the US Health and Retirement Study allows us to gauge the plausibility of two competing explanations for this difference: a contextual effect of self-employment on health (benefit effect), or a health-related selection of individuals into self-employment (barrier effect). Our main finding is that the selection of comparatively healthier individuals into self-employment accounts for the positive cross-sectional difference. The results rule out a positive contextual effect of self-employment on health, and we present tentative evidence that, if anything, engaging in self-employment is bad for one's health. Given the importance of the self-employed in the economy, these findings contribute to our understanding of the vitality of the labor force. Copyright © 2014 John Wiley & Sons, Ltd.

4.
Phys Rev E ; 109(4-1): 044205, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38755835

RESUMEN

This article confronts the formidable task of exploring chaos within hidden attractors in nonlinear three-dimensional autonomous systems, highlighting the lack of established analytical and numerical methodologies for such investigations. As the basin of attraction does not touch the unstable manifold, there are no straightforward numerical processes to detect those attractors and one has to implement special numerical and analytical strategies. In this article we present an alternative approach that allows us to predict the basin of attraction associated with hidden attractors, overcoming the existing limitations. The method discussed here is based on the Kosambi-Cartan-Chern theory which enables us to conduct a comprehensive theoretical analysis by means of evaluating geometric invariants and instability exponents, thereby delineating the regions encompassing chaotic and periodic zones. Our analytical predictions are thoroughly validated by numerical results.

5.
J Syst Integr Neurosci ; 6(2)2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33614164

RESUMEN

Research into the neurogenetic basis of addiction identified and characterized by Reward Deficiency Syndrome (RDS) includes all drug and non-drug addictive, obsessive and compulsive behaviors. We are proposing herein that a new model for the prevention and treatment of Substance Use Disorder (SUD) a subset of RDS behaviors, based on objective biologic evidence, should be given serious consideration in the face of a drug epidemic. The development of the Genetic Addiction Risk Score (GARS) followed seminal research in 1990, whereby, Blum's group identified the first genetic association with severe alcoholism published in JAMA. While it is true that no one to date has provided adequate RDS free controls there have been many studies using case -controls whereby SUD has been eliminated. We argue that this deficiency needs to be addressed in the field and if adopted appropriately many spurious results would be eliminated reducing confusion regarding the role of genetics in addiction. However, an estimation, based on these previous literature results provided herein, while not representative of all association studies known to date, this sampling of case- control studies displays significant associations between alcohol and drug risk. In fact, we present a total of 110,241 cases and 122,525 controls derived from the current literature. We strongly suggest that while we may take argument concerning many of these so-called controls (e.g. blood donors) it is quite remarkable that there are a plethora of case -control studies indicating selective association of these risk alleles ( measured in GARS) for the most part indicating a hypodopaminergia. The paper presents the detailed methodology of the GARS. Data collection procedures, instrumentation, and the analytical approach used to obtain GARS and subsequent research objectives are described. Can we combat SUD through early genetic risk screening in the addiction field enabling early intervention by the induction of dopamine homeostasis? It is envisaged that GARS type of screening will provide a novel opportunity to help identify causal pathways and associated mechanisms of genetic factors, psychological characteristics, and addictions awaiting additional scientific evidence including a future meta- analysis of all available data -a work in progress.

6.
Behav Brain Res ; 176(1): 149-69, 2007 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-16950524

RESUMEN

Clinical observations suggest that certain gut and dietary factors may transiently worsen symptoms in autism spectrum disorders (ASD), epilepsy and some inheritable metabolic disorders. Propionic acid (PPA) is a short chain fatty acid and an important intermediate of cellular metabolism. PPA is also a by-product of a subpopulation of human gut enterobacteria and is a common food preservative. We examined the behavioural, electrophysiological, neuropathological, and biochemical effects of treatment with PPA and related compounds in adult rats. Intraventricular infusions of PPA produced reversible repetitive dystonic behaviours, hyperactivity, turning behaviour, retropulsion, caudate spiking, and the progressive development of limbic kindled seizures, suggesting that this compound has central effects. Biochemical analyses of brain homogenates from PPA treated rats showed an increase in oxidative stress markers (e.g., lipid peroxidation and protein carbonylation) and glutathione S-transferase activity coupled with a decrease in glutathione and glutathione peroxidase activity. Neurohistological examinations of hippocampus and adjacent white matter (external capsule) of PPA treated rats revealed increased reactive astrogliosis (GFAP immunoreactivity) and activated microglia (CD68 immunoreactivity) suggestive of a neuroinflammatory process. This was coupled with a lack of cytotoxicity (cell counts, cleaved caspase 3' immunoreactivity), and an increase in phosphorylated CREB immunoreactivity. We propose that some types of autism may be partial forms of genetically inherited or acquired disorders involving altered PPA metabolism. Thus, intraventricular administration of PPA in rats may provide a means to model some aspects of human ASD in rats.


Asunto(s)
Trastorno Autístico/fisiopatología , Encéfalo/fisiopatología , Conducta Exploratoria , Ácidos Grasos Volátiles/metabolismo , Propionatos/metabolismo , Animales , Trastorno Autístico/inducido químicamente , Trastorno Autístico/metabolismo , Encéfalo/metabolismo , Encéfalo/patología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Estimulación Eléctrica , Ácidos Grasos Volátiles/administración & dosificación , Ácidos Grasos Volátiles/toxicidad , Hipocampo/metabolismo , Hipocampo/patología , Hipocampo/fisiopatología , Inyecciones Intraventriculares , Excitación Neurológica/patología , Masculino , Actividad Motora , Neocórtex/metabolismo , Neocórtex/fisiopatología , Neostriado/metabolismo , Neostriado/patología , Neostriado/fisiopatología , Estrés Oxidativo , Propionatos/administración & dosificación , Propionatos/toxicidad , Distribución Aleatoria , Ratas , Ratas Long-Evans
7.
Oncogene ; 36(3): 397-409, 2017 01 19.
Artículo en Inglés | MEDLINE | ID: mdl-27345397

RESUMEN

Retrograde signaling is a mechanism by which mitochondrial dysfunction is communicated to the nucleus for inducing a metabolic shift essential for cell survival. Previously, we showed that partial mitochondrial DNA (mtDNA) depletion in different cell types induced mitochondrial retrograde signaling pathway (MtRS) involving Ca+2-sensitive Calcineurin (Cn) activation as an immediate upstream event of stress response. In multiple cell types, this stress signaling was shown to induce tumorigenic phenotypes in immortalized cells. In this study we show that MtRS also induces p53 expression, which was abrogated by Ca2+ chelators and short hairpin RNA-mediated knockdown of CnAß mRNA. Mitochondrial dysfunction induced by mitochondrial ionophore, carbonyl cyanide m-chlorophenyl hydrazone and other respiratory inhibitors, which perturb the transmembrane potential, were equally efficient in inducing the expression of p53 and downregulation of MDM2. Stress-induced p53 physically interacted with hypoxia-inducible factor-1α (HIF-1α) and attenuated the latter's binding to promoter DNA motifs. In addition, p53 promoted ubiquitination and degradation of HIF-1α in partial mtDNA-depleted cells. The mtDNA depleted cells, with inhibited HIF-1α, showed upregulation of glycolytic pathway genes, glucose transporter 1-4 (Glut1-4), phosphoglycerate kinase 1 and Glucokinase but not of prolyl hydroxylase isoforms. For the first time we show that p53 is induced as part of MtRS and it renders HIF-1α inactive by physical interaction. In this respect, our results show that MtRS induces tumor growth independent of the HIF-1α pathway.


Asunto(s)
Calcineurina/metabolismo , Calcio/metabolismo , ADN Mitocondrial/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Mitocondrias/genética , Proteína p53 Supresora de Tumor/metabolismo , Células A549 , Animales , Secuencia de Bases , Células COS , Línea Celular Tumoral , Células HCT116 , Humanos , Ratones , Unión Proteica , Ratas , Eliminación de Secuencia , Transducción de Señal , Ubiquitinación
9.
J UOEH ; 28(2): 157-71, 2006 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-16780224

RESUMEN

Lead is one of the industrially important heavy metals that causes male reproductive impairment among battery and paint factory workers, but information on the structure-function integrity of human spermatozoa is still limited. Therefore, it was necessary to investigate the effect of lead on sperm structure and functional activity in these workers. Oligozoospermia with concomitant lowering of sperm protein and nucleic acid content and the percentage of sperm DNA hyploidy (P <0.001) suggested the diminution of sperm cell production after occupational lead exposure. Low sperm vitality and hypoosmotic swelling percentage along with high malondialdehyde content and altered seminal plasma ascorbate level (P<0.001) indicating damage of sperm cell surface, might be due to high membrane lipid peroxidation and failure of non-enzymatic antioxidant protection after lead exposure. Alteration of sperm membrane surface was also evidenced from scanning electron microscopy and further authenticated by atomic and lateral force microscopy. Lowering of sperm velocity, gross and forward progressive motility with high stationary motile spermatozoa (P<0.001) suggested retarded sperm activity among the exposed workers, which was supported by high seminal plasma fructose level and reduced activity of sperm ATPase (P < 0.001). Increased incidence of teratozoospermia was also associated with high blood and semen lead level (PbB, PbS) (P<0.001). Therefore, the results suggested that lead not only affects the sperm count, but also damages the sperm structure and membrane integrity, motility and functional activity among the battery and paint factory workers.


Asunto(s)
Plomo/efectos adversos , Exposición Profesional/efectos adversos , Pintura , Espermatozoides/efectos de los fármacos , Espermatozoides/fisiología , Industria Química , Humanos , Masculino , Motilidad Espermática , Espermatozoides/citología
10.
Indian J Cancer ; 53(1): 29-33, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27146734

RESUMEN

BACKGROUND: Neo-adjuvant chemotherapy (NAC) in locally advanced breast cancer is the present trend. Following NAC, a considerable alteration of morphology occurs in the tumor. AIMS: To study effects of NAC on morphology of breast carcinoma and to evaluate the pathologic response (PR). MATERIALS AND METHODS: A total of 39 surgically resected mastectomy specimens of patients of invasive locally advanced breast carcinoma who received NAC were evaluated for macroscopic and microscopic (by routine stains and immunohistochemistry) alteration of morphology. RESULTS: Macroscopically well-defined tumor noted in 25 cases (64.1%) and in the rest (14 cases, 35.9%), only fibrotic areas identified. Microscopic examination identified malignant cells in 29 (74.4%), significant chronic inflammation in 24 (61.5%), hyalinized fibrosed stroma in 25 (64.1%) and necrosis in 11 (28.2%) cases. Immunohistochemistry assisted in differentiating malignant cells from histiocytes. In 15 cases (38.5%), axillary lymph nodes isolated where fibrosis seen in 12 (30.8%) and malignant cell in 8 (20.5%) cases. In 34 cases where the pre-treatment biopsy were available, complete pathologic response (pCR) and partial pathologic response (pPR) were achieved in 7 (20.6%) and 23 (67.4%) cases respectively. DISCUSSION: Protocol of systematic evaluation of morphological changes is different in cases of a patient treated by NAC. Nature of malignancy was difficult to categorize as morphology of typical breast carcinomas were altered. Sometimes, immunohistochemistry is advantageous as routine H and E stains are not sufficient to isolate malignant cells in fibrotic and necrotic areas. Appropriate morphological evaluation of the mastectomy specimen is absolutely crucial for assessment of PR and subsequent management.


Asunto(s)
Neoplasias de la Mama/tratamiento farmacológico , Adulto , Neoplasias de la Mama/patología , Quimioterapia Adyuvante , Femenino , Humanos , Persona de Mediana Edad , Terapia Neoadyuvante
12.
Acad Emerg Med ; 9(1): 15-21, 2002 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11772664

RESUMEN

BACKGROUND/OBJECTIVE: Patient satisfaction has been associated with patient perceptions of emergency department (ED) wait intervals, but not necessarily actual wait intervals. The objective was to address the associations of actual versus perceived wait intervals in ED patients and the association of overall satisfaction with perceived and actual wait intervals. METHODS: The authors performed a prospective, cross-sectional study using a volume-stratified sample of adult ED patients presenting to an urban, university teaching hospital. Patient wait intervals were monitored using a computerized tracking system. Patients were confidentially surveyed regarding their overall satisfaction with care and perceptions of wait intervals after a disposition decision was made by the treating physician. The Spearman's rho (two-tailed, alpha = 0.05) was used to evaluate the association between patient satisfaction and perceived wait intervals, estimated wait intervals, and measured wait intervals. Associations between these measures of wait intervals were similarly assessed. RESULTS: One hundred twenty-six eligible patients (including 15 admissions) completed the survey. The median wait interval (interquartile range [IQR] was 14 (7 to 22) minutes to a room. Overall satisfaction was more strongly associated with the perception that the wait interval to a room was shorter than expected (r = 0.44; p = 0.00001) than with the estimated wait interval (r = 0.03; p = 0.97) or the measured wait interval (r = -0.06; p = 0.49). Patients had a median wait interval of 13 (3 to 26) minutes in a room until seen by a physician. Overall satisfaction was more strongly associated with the perception of the physician wait interval's being shorter than expected (r = 0.37; p = 0.00001) than with the estimated wait interval (r = -0.09; p = 0.32) or the measured wait interval (r = 0.05; p = 0.58). Similar findings were found for the total time in the ED. For both the wait for a room interval and the wait for a physician interval, the measured wait intervals were more strongly associated with the estimated wait intervals (r = 0.63 and r = 0.34, respectively) than with the perception that the wait intervals were shorter than expected (r = -0.20 and r = -0.17, respectively). CONCLUSIONS: Efforts to improve ED patient satisfaction should focus on improving patients' perceptions that wait intervals are appropriate rather than simply shortening wait intervals per se.


Asunto(s)
Servicio de Urgencia en Hospital/normas , Satisfacción del Paciente/estadística & datos numéricos , Administración del Tiempo , Adulto , Anciano , Estudios Transversales , Femenino , Encuestas de Atención de la Salud , Hospitales de Enseñanza/normas , Hospitales Urbanos/normas , Humanos , Masculino , Persona de Mediana Edad , Oregon , Evaluación de Resultado en la Atención de Salud , Probabilidad , Estudios Prospectivos
13.
Acad Emerg Med ; 9(12): 1379-88, 2002 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-12460841

RESUMEN

OBJECTIVES: To assess and compare overall satisfaction in pediatric emergency department (ED) patients and their accompanying parents. To identify aspects of health care delivery that influence satisfaction in these groups. METHODS: Pediatric patients (ages 5-17 years) and their parents (or guardians) seen at a university hospital pediatric ED were eligible. A convenience sample of English-speaking subject pairs (n = 101 pairs) was enrolled. Questionnaires were administered to both children and their parents at the completion of their ED care. The survey instruments used a modified Wong-Baker FACES Pain Rating Scale and a six-point interval scale. Factors measured included overall satisfaction, perceptions of pain and fear, and other characteristics of the ED visit. Data were analyzed using paired Wilcoxon signed-rank tests, Spearman rank correlation coefficients, and Fischer's exact chi-square tests (alpha = 0.05) where appropriate. RESULTS: Parent satisfaction was associated with the quality of provider-patient interactions (R = 0.54, p = 0.0001), the adequacy of information provided (R = 0.47, p = 0.0001), and shorter waiting room times (R = -0.24, p = 0.01). Child satisfaction was associated with the quality of provider-patient interactions (R = 0.24, p 0.04), adequacy of information provided (R = 0.51, p = 0.003), and resolution of pain (R = 0.25, p = 0.03). Parent estimates were similar to children's initial pain scores; however, children reported greater resolution of pain than appreciated by their parents (p = 0.006). CONCLUSIONS: Satisfaction can be validly and reliably measured in pediatric patients using a visual scale instrument. Factors that influence patient satisfaction were similar among both children and their parents. The influence of pain resolution on pediatric ED satisfaction is a novel finding, which demonstrates the importance of appropriate pain and anxiety assessment and treatment in children.


Asunto(s)
Servicio de Urgencia en Hospital/normas , Satisfacción del Paciente/estadística & datos numéricos , Pediatría/normas , Adolescente , Distribución de Chi-Cuadrado , Niño , Preescolar , Estudios Transversales , Encuestas de Atención de la Salud , Humanos , Modelos Lineales , Oregon , Dimensión del Dolor , Relaciones Médico-Paciente , Proyectos Piloto , Estudios Prospectivos
14.
Phys Rev E Stat Nonlin Soft Matter Phys ; 70(5 Pt 2): 058401, 2004 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-15600811

RESUMEN

The theory of electromagnetic surface modes propagating along the planar interface between dusty electron-positron plasma and vacuum is reexamined by the conventional matching method of boundary conditions. It is shown that in a magnetoplasma the direct use of specular reflection method is not appropriate and the derivations for the TM-mode dispersion relation [Phys. Rev. E 61, 4357 (2000)] are incorrect.

15.
Ind Health ; 41(3): 295-7, 2003 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12916763

RESUMEN

Formaldehyde (HCHO) exposure in industry causes health impairment, especially immune profile. Male albino rats when exposed to HCHO at 5, 10, 15 mg/kg day for 30 days showed decrease in thyroid weight in 10, 15 mg/kg/day HCHO fed group with commensurate follicular regression (epithelial cells), decreased triiodothyronine (T3), thyroxin (T4) deficiency and enhanced thyroid stimulating hormone (TSH). Repeated chemical stimulation might have increased thyroid activity of the follicles and rapidly deteriorated the capacity for synthesis of thyroxin hormone and thus becomes atrophied. The chronic action of HCHO on thyroid may be due to a block at the source of thyroid hormone (s).


Asunto(s)
Formaldehído/toxicidad , Glándula Tiroides/efectos de los fármacos , Animales , Relación Dosis-Respuesta a Droga , India , Masculino , Tamaño de los Órganos/efectos de los fármacos , Ratas , Glándula Tiroides/fisiopatología , Tirotropina/sangre , Tiroxina/sangre , Triyodotironina/sangre
16.
PLoS One ; 9(7): e102672, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25033272

RESUMEN

Recent studies in psychophysiology show an increased attention for examining the reliability of Event-Related Potentials (ERPs), which are measures of cognitive control (e.g., Go/No-Go tasks). An important index of reliability is the internal consistency (e.g., Cronbach's alpha) of a measure. In this study, we examine the internal consistency of the N2 and P3 in a Go/No-Go task. Furthermore, we attempt to replicate the previously found internal consistency of the Error-Related Negativity (ERN) and Positive-Error (Pe) in an Eriksen Flanker task. Healthy participants performed a Go/No-Go task and an Eriksen Flanker task, whereby the amplitudes of the correct No-Go N2/P3, and error trials for ERN/Pe were the variables of interest. This study provides evidence that the N2 and P3 in a Go/No-Go task are internally consistent after 20 and 14 trials are included in the average, respectively. Moreover, the ERN and Pe become internally consistent after approximately 8 trials are included in the average. In addition guidelines and suggestions for future research are discussed.


Asunto(s)
Ondas Encefálicas/fisiología , Cognición/fisiología , Potenciales Evocados/fisiología , Desempeño Psicomotor/fisiología , Adulto , Atención/fisiología , Encéfalo/fisiología , Mapeo Encefálico , Electroencefalografía , Femenino , Lateralidad Funcional/fisiología , Humanos , Masculino , Psicofisiología , Tiempo de Reacción/fisiología , Encuestas y Cuestionarios , Adulto Joven
17.
Physiol Behav ; 119: 110-4, 2013 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-23770427

RESUMEN

Previous research has suggested a positive association between testosterone (T) and entrepreneurial behavior in males. However, this evidence was found in a study with a small sample size and has not been replicated. In the present study, we aimed to verify this association using two large, independent, population-based samples of males. We tested the association of T with entrepreneurial behavior, operationalized as self-employment, using data from the Rotterdam Study (N=587) and the Study of Health in Pomerania (N=1697). Total testosterone (TT) and sex hormone-binding globulin (SHBG) were measured in the serum. Free testosterone (FT), non-SHBG-bound T (non-SHBG-T), and the TT/SHBG ratio were calculated and used as measures of bioactive serum T, in addition to TT adjusted for SHBG. Using logistic regression models, we found no significant associations between any of the serum T measures and self-employment in either of the samples. To our knowledge, this is the first large-scale study on the relationship between serum T and entrepreneurial behavior.


Asunto(s)
Emprendimiento , Testosterona/sangre , Anciano , Estudios Transversales , Humanos , Masculino , Persona de Mediana Edad , Globulina de Unión a Hormona Sexual/metabolismo
19.
SAR QSAR Environ Res ; 23(3-4): 327-43, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22432416

RESUMEN

In the first part of this paper, we present a novel graphical representation of proteins, which starts with constructing a map of a protein that is obtained from a matrix, the elements of which record the adjacencies of pairs of amino acids in the primary structure of a protein. Starting with the novel protein map, one interprets its matrix elements as vertices of a graph, which are labelled in sequential order as in the protein sequence. The nearest vertices are connected to the nearest neighbour which has a smaller label. In the second part of this paper, we describe the construction of protein binary codes that can serve as protein descriptors. This novel graphical representation of proteins is illustrated on segments of trans-membrane proteins, which are embedded in the membrane.


Asunto(s)
Gráficos por Computador , Proteínas de la Membrana/química , Análisis de Secuencia de Proteína/métodos , Aminoácidos/química , Simulación por Computador , Insulina/química , Insulina Glargina , Insulina de Acción Prolongada/química
20.
Pharmacognosy Res ; 4(1): 15-21, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22224056

RESUMEN

BACKGROUND: Black tea (Camellia sinensis) has been used as a daily beverage for time immemorial. Immunomodulatory effects of tea are recognized as it stimulates the proliferation of cultured human peripheral blood mononuclear cells. Anti-inflammatory effects of tea have also been depicted in the available literature. Therefore, we designed this study to examine the potential immunemodulatory and anti-inflammatory activities of black tea in a rat model and in human peripheral mononuclear cells. AIMS: The purpose of the study was to determine (1) evaluation of anti-inflammatory effects of black tea on rats, (2) evaluation of immunemodulator effects of black tea on rats, and (3) evaluation of immunemodulator effects of black tea on human peripheral mononuclear cells. MATERIALS AND METHODS: Black tea decoction (10% and 20%) was prepared. Acute anti-inflammatory activity of tea decoction was evaluated using carrageenan and dextran whereas chronic anti-inflammatory (Immunomodulatory) effects were evaluated in a complete Freunds' adjuvant-induced arthritis model. Immunostimulatory role was evaluated in cultured human (in vitro) peripheral mononuclear cells (T-lymphocytes) by using methyl thioazolyl tetrazolium (MTT) and Trypan blue assay. STUDY DESIGN: An experimental study was designed. RESULTS: Black tea decoction (10% and 20%) strength has shown significant anti-inflammatory effects (64.8% and 77% reduction, respectively), on carrageenan-induced acute inflammatory models (rat paw edema) which can be comparable with the standard drug indomethacin (89.1%). In a chronic anti-inflammatory model, black tea decoction (10% and 20%) has shown significant suppressive effects on rat paw edema (38.56% and 69.53%) observed on 21(st) day. Lymphoproliferative action of tea was evaluated on human peripheral mononuclear cells using an MTT assay where the number of living cells were expressed in terms of optical density at 570 nm. An experiment has shown that black tea increases the maximum number of T-lymphocytes at 72 h with a maximum strength of 20%. Maximum number of viable cells (T-lymphocytes) was observed with black tea at 20% strength at 72 h. The results were expressed as mean ± SD, and the significance was evaluated by Student's t-test versus control, with P < 0.05 implying significance. CONCLUSIONS: Taken together, our data indicate that black tea has potential anti-inflammatory and immunomodulatory action and this corroborates with the current trend of tea being promoted as a 'health drink'.

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