43 research outputs found

    Formation of the seed black holes: a role of quark nuggets?

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    Strange quark nuggets (SQNs) could be the relics of the cosmological QCD phase transition, and they could very likely be the candidate of cold quark matter if survived the cooling of the later Universe, although the formation and evolution of these SQNs depend on the physical state of the hot QGP (quark-gluon plasma) phase and the state of cold quark matter. We reconsider the possibility of SQNs as cold dark matter, and find that the formation of black holes in primordial halos could be significantly different from the standard scenario. In a primordial halo, the collision between gas and SQNs could be frequent enough, and thus the viscosity acting on each SQN would decrease its angular momentum and make it to sink into the center of the halo, as well as heat the gas. The SQNs with baryon numbers less than 103510^{35} could assemble in the center of the halo before the formation of primordial stars. A black hole could form by merger of these SQNs, and then its mass could quickly become about 103 M10^3\ M_\odot or higher, by accreting the surrounding SQNs or gas. The black holes formed in this way could be the seeds for the supermassive black holes at redshift as high as z6z\sim 6.Comment: 15 page

    ZnO-mesoporous glass scaffolds loaded with osteostatin and mesenchymal cells improve bone healing in a rabbit bone defect

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    The use of 3D scaffolds based on mesoporous bioactive glasses (MBG) enhanced with therapeutic ions, biomolecules and cells is emerging as a strategy to improve bone healing. In this paper, the osteogenic capability of ZnO-enriched MBG scaffolds loaded or not with osteostatin (OST) and human mesenchymal stem cells (MSC) was evaluated after implantation in New Zealand rabbits. Cylindrical meso-macroporous scaffolds with composition (mol %) 82.2SiO2–10.3CaO–3.3P2O5–4.2ZnO (4ZN) were obtained by rapid prototyping and then, coated with gelatin for easy handling and potentiating the release of inorganic ions and OST. Bone defects (7.5 mm diameter, 12 mm depth) were drilled in the distal femoral epiphysis and filled with 4ZN, 4ZN + MSC, 4ZN + OST or 4ZN + MSC + OST materials to evaluate and compare their osteogenic features. Rabbits were sacrificed at 3 months extracting the distal third of bone specimens for necropsy, histological, and microtomography (µCT) evaluations. Systems investigated exhibited bone regeneration capability. Thus, trabecular bone volume density (BV/TV) values obtained from µCT showed that the good bone healing capability of 4ZN was significantly improved by the scaffolds coated with OST and MSC. Our findings in vivo suggest the interest of these MBG complete systems to improve bone repair in the clinical practice

    Evaluación urodinámica y comparativa de la calidad de vida en pacientes con trastorno de vaciamiento vesical sometidos a terapia InterStim, Medtronic®

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    ResumenAntecedentesDesde 1980 la terapia de neuroestimulación sacra ha demostrado ser una terapia válida y alternativa en el manejo de los trastornos miccionales por patología del tracto urinario bajo, siendo sus principales indicaciones la retención urinaria idiopática, la incontinencia de urgencia y la incontinencia fecal. En nuestro país sigue siendo una terapia novedosa y no se cuenta aún con estudios que evalúen esta eficacia en términos de calidad de vida o con parámetros cuantitativos.Objetivo del estudioEstablecer la eficacia de la terapia de neuroestimulación sacra tipo InterStim, Medtronic®, en el manejo de los pacientes con trastornos de vaciamiento vesical, efectuando un análisis urodinámico y de la calidad de vida comparativo previo y posterior al tratamiento, determinando los volúmenes miccionales, los períodos de incontinencia, la satisfacción del paciente y la calidad de vida.Material y métodosDesde enero de 2010 hasta junio de 2013, en el Hospital Central Militar se realizó evaluación urodinámica y comparativa de la calidad de vida mediante el empleo del instrumento SF-36 v2 (versión mexicana) e ICIQSF, en los pacientes que presentaron trastorno de vaciamiento vesical de etiología no obstructiva y que fueron refractarios a tratamiento médico.ResultadosSe incluyeron 10 pacientes en el estudio, bajo los siguientes diagnósticos: disinergia detrusor-esfínter, vejiga hiperactiva y retención urinaria no obstructiva, ubicados por género (2 masculinos y 8 femeninos). En la totalidad de los pacientes se presentó mejoría del 50% o superior durante la fase de prueba de la terapia de neuroestimulación, y se colocó fase definitiva con los siguientes resultados: se obtuvieron resultados equivalentes al 50-65% de mejoría en los parámetros cualitativos de función física, función social y rol emocional, así como en las variables cuantitativas de volumen de vaciamiento, eficacia de vaciamiento y disminución de los períodos de incontinencia.DiscusiónComo se ha establecido a nivel de la literatura mundial, nuestros resultados fueron similares en el efecto benéfico y la eficacia en la calidad de vida e incontinencia urinaria, respectivamente, y se reportan porcentajes de éxito mayores al 50% en el cese total de los episodios de incontinencia.ConclusionesLa neuromodulación mediante la estimulación del nervio sacro es una forma exitosa de tratamiento en los trastornos de vaciamiento vesical de etiología no obstructiva y refractaria al tratamiento médico, es segura, mínimamente invasiva y de fácil aplicación, y mejora la calidad de vida de los pacientes. Sin embargo, es necesario realizar estudios aleatorizados y que consideren parámetros objetivos (urodinámicos), así como las complicaciones posibles a mediano y largo plazo en este tipo de terapia.AbstractBackgroundSince 1980, sacral neuromodulation therapy has been shown to be a valid alternative therapy in the management of urinary disorders due to lower urinary tract pathology, and its primary indications are: idiopathic urinary retention, urge incontinence, and fecal incontinence. It is still considered a novel therapy in Mexico and there are no studies using quantitative parameters that evaluate its efficacy in terms of quality of life.AimsTo establish the efficacy of the Medtronic InterStim® sacral neuromodulation therapy in the management of patients with bladder voiding disorders through urodynamic and quality of life analyses before and after treatment. Urine volume, periods of incontinence, patient satisfaction, and quality of life were determined.MethodsA comparative urodynamic and quality of life evaluation was carried out using the SF-36 v2 (Mexican version) and the ICIQSF instruments on patients presenting with nonobstructive bladder voiding disorders that were refractory to medical treatment.ResultsTen patients with the following diagnoses were included in the study: detrusor sphincter dyssynergia, overactive bladder, and nonobstructive urinary retention. Two of the patients were men and 8 were women. There was a 50% or greater improvement in all 10 patients during the test phase of the neuromodulation therapy and the definitive placement phase produced the following results: a 50-65% improvement in the qualitative parameters of physical function, social function, and emotional role, as well as in the quantitative variables of voiding volume, voiding efficacy, and reduced periods of incontinence.DiscussionOur results were similar to those established in the international literature in relation to the beneficial effect on quality of life and efficacy in urinary incontinence management; the literature reports success percentages in the complete cessation of incontinence episodes at above 50%.ConclusionsNeuromodulation through sacral nerve stimulation is a successful form of treatment of nonobstructive and medical treatment-refractory bladder voiding disorders. It is safe, minimally invasive, and easy to apply and it improves patient quality of life. Nevertheless, further randomized studies on this type of therapy need to be conducted that take into account objective parameters (urodynamics) and possible medium and long-term complications

    Eficiência de filtros de areia pressurizados na remoção de diferentes tamanhos de partículas da água de irrigação

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    Resumo:O objetivo deste trabalho foi avaliar a eficiência de filtros de areia com diferentes granulometrias na remoção de diferentes tamanhos de partículas da água de irrigação, bem como a perda de pressão em função da taxa de filtração e da granulometria de areia do leito filtrante. Os ensaios foram realizados com três filtros de um mesmo modelo comercial, testados com diferentes combinações de granulometrias de areia (areia fina, 0,55 mm; média, 0,77 mm; e grossa, 1,04 mm de diâmetro) e taxas de filtração (20, 40, 60 e 75 m3m-2 h-1), e repetidos em três ciclos de filtração de 4 horas (C1, C2 e C3, realizados em 3 dias consecutivos). O filtro de areia avaliado é efetivo na remoção de partículas a partir do tamanho de areia fina (>60 μm). Nesta faixa de remoção de partículas, a influência da taxa de filtração aumenta com a diminuição do tamanho de partícula na água. O aumento na taxa de filtração, associado à diminuição da granulometria de areia, aumenta a eficiência de remoção, mas acentua a perda de pressão com o tempo, o que diminui a remoção das partículas menores ao longo dos ciclos de filtração

    Natural clusters of tuberous sclerosis complex (TSC)-associated neuropsychiatric disorders (TAND): new findings from the TOSCA TAND research project.

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    BACKGROUND: Tuberous sclerosis complex (TSC)-associated neuropsychiatric disorders (TAND) have unique, individual patterns that pose significant challenges for diagnosis, psycho-education, and intervention planning. A recent study suggested that it may be feasible to use TAND Checklist data and data-driven methods to generate natural TAND clusters. However, the study had a small sample size and data from only two countries. Here, we investigated the replicability of identifying natural TAND clusters from a larger and more diverse sample from the TOSCA study. METHODS: As part of the TOSCA international TSC registry study, this embedded research project collected TAND Checklist data from individuals with TSC. Correlation coefficients were calculated for TAND variables to generate a correlation matrix. Hierarchical cluster and factor analysis methods were used for data reduction and identification of natural TAND clusters. RESULTS: A total of 85 individuals with TSC (female:male, 40:45) from 7 countries were enrolled. Cluster analysis grouped the TAND variables into 6 clusters: a scholastic cluster (reading, writing, spelling, mathematics, visuo-spatial difficulties, disorientation), a hyperactive/impulsive cluster (hyperactivity, impulsivity, self-injurious behavior), a mood/anxiety cluster (anxiety, depressed mood, sleep difficulties, shyness), a neuropsychological cluster (attention/concentration difficulties, memory, attention, dual/multi-tasking, executive skills deficits), a dysregulated behavior cluster (mood swings, aggressive outbursts, temper tantrums), and an autism spectrum disorder (ASD)-like cluster (delayed language, poor eye contact, repetitive behaviors, unusual use of language, inflexibility, difficulties associated with eating). The natural clusters mapped reasonably well onto the six-factor solution generated. Comparison between cluster and factor solutions from this study and the earlier feasibility study showed significant similarity, particularly in cluster solutions. CONCLUSIONS: Results from this TOSCA research project in an independent international data set showed that the combination of cluster analysis and factor analysis may be able to identify clinically meaningful natural TAND clusters. Findings were remarkably similar to those identified in the earlier feasibility study, supporting the potential robustness of these natural TAND clusters. Further steps should include examination of larger samples, investigation of internal consistency, and evaluation of the robustness of the proposed natural clusters
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