Dynamics of Counterion Condensation

Using a generalization of the Poisson-Boltzmann equation, dynamics of counterion condensation is studied. For a single charged plate in the presence of counterions, it is shown that the approach to equilibrium is diffusive. In the far from equilibrium case of a moving charged plate, a dynamical counterion condensation transition occurs at a critical velocity. The complex dynamic behavior of the counterion cloud is shown to lead to a novel nonlinear force-velocity relation for the moving plate.Comment: 5 pages, 1 ps figure included using eps

Quantitative study of molecular N_2 trapped in disordered GaN:O films

The structure of disordered GaN:O films grown by ion-assisted deposition is investigated using x-ray absorption near-edge spectroscopy and Raman spectroscopy. It is found that between 4 and 21 % of the nitrogen in the films is in the form of molecular N_2 that interacts only weakly with the surrounding matrix. The anion to cation ratio in the GaN:O host remains close to unity, and there is a close correlation between the N_2 fraction, the level of oxygen impurities, and the absence of short-range order in the GaN:O matrix.Comment: 5 pages, 3 figure

Diferentes teores de proteína metabolizável em rações com cana-de-açúcar para vacas em lactação.

O presente trabalho teve como objetivo avaliar o efeito de diferentes teores de proteína metabolizável (PM) na ração de vacas lactantes alimentadas com cana-de-açúcar

Human respiratory syncytial virus in children hospitalized for acute lower respiratory infection

OBJETIVO: Avaliar a prevalência e a sazonalidade do vírus respiratório sincicial humano (VRSH) em crianças de 0 a 6 anos hospitalizadas por infecção aguda das vias aéreas inferiores (IVAI) em São José do Rio Preto (SP) e a associação entre faixa etária, diagnóstico e VRSH. MÉTODOS: Entre maio de 2004 e setembro de 2005, foram estudados 290 episódios consecutivos de IVAI adquiridos na comunidade em crianças de 0 a 6 anos internadas no Hospital de Base de São José do Rio Preto. Para identificação do VRSH, foram coletadas amostras de secreção de nasofaringe e realizou-se análise molecular por meio da técnica de RT-PCR. RESULTADOS: A prevalência de VRSH foi de 29,3% nos episódios de IVAI hospitalizados. A IVAI foi frequente em lactentes (mediana de idade = 13,5 meses). O VRSH foi mais frequente nos casos de bronquiolite (64%) e no primeiro ano de vida (35%). Os episódios de infecção por VRSH ocorreram entre o outono e a primavera, com frequência maior em 2004 do que em 2005. Os critérios clínicos e radiológicos não foram suficientes para o diagnóstico de infecção pelo VRSH. Em 78,8% dos episódios de VRSH, houve tratamento com antibiótico. CONCLUSÕES: A prevalência do VRSH em crianças de 0 a 6 anos hospitalizadas por IVAI foi elevada, com predomínio nas mais jovens ou com bronquiolite. A circulação do vírus variou nos dois anos estudados. Os resultados sugerem necessidade de diagnóstico laboratorial do VRSR na prática clínica.OBJECTIVE: To evaluate the prevalence and seasonality of human respiratory syncytial virus (HRSV) in children aged 0 to 6 years, hospitalized with acute lower respiratory infection (ALRI) in São José do Rio Preto, SP, Brazil, and the association between age, diagnosis, and HRSV. METHODS: Between May 2004 and September 2005, we studied 290 consecutive episodes of community-acquired ALRI in children aged 0 to 6 years admitted to the Hospital de Base of São José do Rio Preto. In order to detect HRSV, nasopharyngeal secretion samples were collected and RT-PCR molecular analysis was performed. RESULTS: The HRSV prevalence was 29.3% for the cases of hospitalized patients with ALRI. ALRI was common in infants (median age = 13.5 months). HRSV was more frequent in cases of bronchiolitis (64%) and during the first year of life (35%). Episodes of HRSV infection occurred between fall and spring, showing higher frequency in 2004 than in 2005. Clinical and radiological criteria were not sufficient to establish the diagnosis of infection with HRSV. Antibiotic therapy was used in 78.8% of episodes of HRSV. CONCLUSIONS: There was a high prevalence of HRSV in children aged 0 to 6 years who were hospitalized for ALRI, predominantly in younger patients or those with bronchiolitis. The circulation of the virus varied in the two years studied. Our results suggest the need for laboratory diagnosis of HRSV in the clinical practice

Folate, Vitamin B12 And Homocysteine Status In The Post-folic Acid Fortification Era In Different Subgroups Of The Brazilian Population Attended To At A Public Health Care Center.

Folate and vitamin B12 are essential nutrients, whose deficiencies are considerable public health problems worldwide, affecting all age groups. Low levels of these vitamins have been associated with high concentrations of homocysteine (Hcy) and can lead to health complications. Several genetic polymorphisms affect the metabolism of these vitamins. The aims of this study were to assess folate, vitamin B12 and homocysteine status in distinct Brazilian individuals after the initiation of folic acid fortification by Brazilian authorities and to investigate the effects of RFC1 A80G, GCPII C1561T and MTHFR C677T polymorphisms on folate, vitamin B12 and Hcy levels in these populations. A total of 719 individuals including the elderly, children, as well as pregnant and lactating women were recruited from our health care center. Folate, vitamin B12 and Hcy levels were measured by conventional methods. Genotype analyses of RFC1 A80G, GCPII C1561T and MTHFR C677T polymorphisms were performed by PCR-RFLP. The overall prevalence of folate and vitamin B12 deficiencies were 0.3% and 4.9%, respectively. Folate deficiency was observed only in the elderly (0.4%) and pregnant women (0.3%), whereas vitamin B12 deficiency was observed mainly in pregnant women (7.9%) and the elderly (4.2%). Plasma Hcy concentrations were significantly higher in the elderly (33.6%). Pregnant women carrying the MTHFR 677TT genotype showed lower serum folate levels (p = 0.042) and higher Hcy levels (p = 0.003). RFC1 A80G and GCPII C1561T polymorphisms did not affect folate and Hcy levels in the study group. After a multivariate analysis, Hcy levels were predicted by variables such as folate, vitamin B12, gender, age and RFC1 A80G polymorphism, according to the groups studied. Our results suggest that folate deficiency is practically nonexistent in the post-folic acid fortification era in the subgroups evaluated. However, screening for vitamin B12 deficiency may be particularly relevant in our population, especially in the elderly.141

The Benefits of Physical Activity on Climacteric Women

As the population ages, there is a need of developing ways to prevent or revert the deleterious effects of aging, especially in climacteric women who suffer with the problems caused by hormonal changes. Exercise is a nonmedicated intervention that can be applied on that population. The benefits of physical activity can positively change body composition, increase levels of muscular strength, balance, and functional capacity. Strength training, aerobic exercise, whole body vibration, and aquatic exercises are some of the modalities that health professionals can prescript to these individuals. Although there are many studies about these exercises, a technique called blood flow restriction is emerging as an alternative to high load exercises but with the same benefits

Single phase nanocrystalline GaMnN thin films with high Mn content

Ga₁ˍₓ Mnₓ Nthin films with a Mn content as high as x=0.18 have been grown using ion-assisted deposition and a combination of Rutherford backscattering spectroscopy and nuclear reaction analysis was used to determine their composition. The structure of the films was determined from x-ray diffraction,transmission electron microscopy, and extended x-ray absorption fine structure(EXAFS). The films are comprised of nanocrystals of random stacked GaMnN and there is no evidence of Mn-rich secondary phases or clusters. EXAFS measurements at the Mn and Ga edge are almost identical to those at the Ga edge from Mn-free nanocrystallineGaNfilms, showing that the Mn occupies the Ga lattice sites, and simulated radial distribution functions of possible Mn-rich impurity phases bear no resemblance to the experimental data. The results indicate that these are the most heavily Mn-doped single phase GaNfilms studied to date.The authors gratefully acknowledge financial support from the New Zealand Foundation for Research Science and Technology through its New Economy Research Fund, and through a postdoctoral fellowship of one of the authors B.J.R.. The work of the MacDiarmid Institute is supported by a New Zealand Centre of Research Excellence award. Another author S.G. wishes to thank Education New Zealand for financial support of the EXAFS measurements

Variabilidad de la expresión de las distintas isoformas del receptor de prolactina en células del sistema inmunológico en pacientes con lupus eritematoso sistémico

La identificación de nuevos mecanismos moleculares involucrados en el desarrollo de enfermedades autoinmunes permitirá elaborar nuevas herramientas clínicas para un correcto diagnóstico y seguimiento junto con el diseño de terapias personalizadas que sean más efectivas, que reduzcan la respuesta autorreactiva y resguarden la competencia del sistema inmune. La altaincidencia de enfermedades autoinmunes sobre el sexo femenino, especialmente Lupus Eritematoso Sistémico (LES) indica fuertemente que, siendo las hormonas femeninas un factor clave en la diferenciación fenotípica de los diferentes géneros cromosómicos, éstas podríanestar involucradas en los mecanismos autoinmunes subyacentes y ser un factor de riesgo considerable. Diversos estudios indican que existe una asociación entre hiperprolactinemia y LES sugiriendo así un rol importante de prolactina (PRL) en estos trastornos. Las acciones dePRL están mediadas por su receptor (PRL-R) que puede tener diferentes isoformas incluyendo una isoforma larga (PRL-RL) activadora formada por un dominio extracelular, uno transmembrana y uno transductor de señales intracelulares. La isoforma corta (del inglés “Short 1 b” PRL-RS1b) carece del dominio citoplasmático y por consiguiente no posee señalización intracelular. Las isoformas PRL-RS1b y PRL-RL se encuentran co-expresadas en diferentes tejidos incluyendo órganos linfáticos. Aunque la regulación de las diferentes isoformas del PRL-R ha sido estudiada extensivamente en el tracto reproductor femenino, su expresión en células del sistema inmunees indiscutiblemente desconocida. Debido a que alteraciones en la activación de linfocitos T podrían contribuir al desarrollo de autoinmunidad, la identificación de nuevos blancos terapéuticos relacionados con estas células es de vital importancia para el diseño de nuevasterapias y marcadores pronósticos de la enfermedad. Con estos antecedentes, el objetivo de nuestro trabajo fue evaluar el potencial del estudio de la expresión de ARNm del PRL-R en la enfermedad lúpica enrolando pacientes femeninos en distintas fases de la enfermedad.En este trabajo evaluamos mediante PCR en tiempo real la expresión de ARNm de las diferentes isoformas del PRL-R en células inmunes de sangre periférica de pacientes lúpicos del sexo femenino. Además, correlacionamos los valores obtenidos de la expresión del PRL-Rcon la severidad de la enfermedad. Logramos identificar exitosamente la presencia de PRL-RS1b y PRL-RL en las muestras de pacientes e individuos saludables. Sin embargo, la abundancia de ARNm de ambas isoformas no resultó en diferencias significativas entre pacientes eindividuos saludables del grupo control. Los datos arrojados en este proyecto contribuyen a la comprensión de las interacciones entre el sistema inmune y endócrino en la salud y en la enfermedad en donde nuestro aporte indica que los niveles de PRL-R no cambiarían sustancialmente en la enfermedad lúpica. Además, el éxito del proyecto a largo plazo también contribuirá a la salud pública con el desarrollo de nuevos conocimientos sobre una descripción molecular del PRL-R enfocado en la prognosis de LES.Fil: Miralles, Daniela. Hospital Español de Mendoza (hem) ; Gobierno de la Provincia de Mendoza;Fil: Moreno Sosa, María Tamara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Sánchez, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Bittar, V.. Gobierno de la Provincia de Mendoza. Hospital Central de Mendoza.; ArgentinaFil: Riveros, María Gabriela. Gobierno de la Provincia de Mendoza. Hospital Central de Mendoza.; ArgentinaFil: Pedrosa, P.. Gobierno de la Provincia de Mendoza. Hospital Central de Mendoza.; ArgentinaFil: Jahn, Graciela Alma. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Valdez, Susana Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Mackern Oberti, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentin