Speciation of Arsenic in Ambient Aerosols Collected in Los Angeles

First-time measurements of the potentially toxic inorganic species of arsenic (arsenite arid arsenate) have been obtained in fine (2.5 µm AD) atmospheric particles in the Los Angeles area. A recently developed method that includes procedures for sample collection, preparation, and analysis was used in this study. Size-fractlonated aerosol samples were collected with a high-volume dichotomous virtual impactor that employed polytetrafluoroethylene filters. Results were obtained for the recovery of arsenic standards added to unexposed and collected filters. Data from this study, indicated that the recently developed speciation method can be used to determine concentrations of As(lll) and As(V) In atmospheric particulate matter samples. Size-fractionated aerosol samples were collected in the city of Industry during January and February 1987. In most samples, As(lll) and As( V) were above the detection limit (approximately 1 ng m-3 of either species) in both aerosol size fractions. A greater portion (about 75 percent) of the two species were observed in the fine particles. The As(lll)/As(V) ratio for both particle sizes was close to 1 (I.e., an equal mixture of both species). Comparison of total suspended particulate arsenic measured by the speciation method to that measured by a routine California Air Resources Board-approved procedure showed good agreement (r = 0.94), indicating both methods were approximately equivalent for the collection and analysis of aerosol arsenic

Neuromatch Academy: a 3-week, online summer school in computational neuroscience

Neuromatch Academy (https://academy.neuromatch.io; (van Viegen et al., 2021)) was designed as an online summer school to cover the basics of computational neuroscience in three weeks. The materials cover dominant and emerging computational neuroscience tools, how they complement one another, and specifically focus on how they can help us to better understand how the brain functions. An original component of the materials is its focus on modeling choices, i.e. how do we choose the right approach, how do we build models, and how can we evaluate models to determine if they provide real (meaningful) insight. This meta-modeling component of the instructional materials asks what questions can be answered by different techniques, and how to apply them meaningfully to get insight about brain function

Nutrition and cataract in low-income Mexicans: experience in an Eye Camp

Surgical Eye-camps for cataract treatment of low-income adult Mexicans have been undertaken over the last 10 years. Despite the high prevalence of cataracts among these subjects, no assessment of their nutritional or health status has ever been made. We compare the results obtained for 81 adults (44 men and 37 women) who received treatment in May 1997 with those for a "control" group of age and sex-matched but affluent individuals in Mexico City. a-Tocopherol and b-carotene were assessed and analysed by HPLC and colorimetric procedures, respectively. The plasma tocopherol to cholesterol ratio did not reveal deficiencies of this vitamin, and only 5 patients (2 men and 3 women) had low b-carotene plasma levels. The patients had high BMI values, with 32% of men and 30% of women overweight, and 2% and 14%, respectively, obese, with higher glucose, cholesterol and triglyceride values reflecting enhanced insulin resistance and lipid abnormalities. The alkaline phosphatase values were elevated ,suggesting that many of these blind patients are osteomalacic because they now remain indoors. Although it has been suggested that an adequate intake of carotenes and tocopherol are associated with absence of cataract, this appears not to be the case in our study population. Surveys in Mexico have revealed, however, a highly prevalent deficiency of other vitamins such as niacin and riboflavin, both of which have been proved to be protective against cataract. It appears that nutritional deficiencies, obesity, incipient diabetes and lipid disorders co-exist in modern Mexico. We have identified a need for research to aid the design of preventive nutritional approaches at the population level that could be applied in parallel with ongoing surgical treatmentNutrición y catarata en mexicanos de bajo ingreso: experiencia en un campamento de cirugía de ojos. Durante los últimos 10 años se han llevado a cabo en México Campamentos Quirúrgicos para el tratamiento de catarata en sujetos de escasos recursos. A pesar de la alta prevalencia de catarata, nunca se ha valorado el estado de nutrición ni de salud de éstas poblaciones. En este estudio comparamos los resultados obtenidos en 81 adultos (44 hombres y 37 mujeres) que recibieron tratamiento en Mayo de 1977, con los de un grupo "control" de sujetos de mayor afluencia, pareados para edad y sexo. Se valoraron los niveles de a-tocoferol y b-carotenos los cuales se analizaron con HPLC y colorimetría respectivamente. La relación tocoferol:colesterol en plasma no reveló deficiencia de ésta vitamina, y se encontraron niveles plasmáticos bajos de b-carotenos en solo 5 sujetos (2 hombres y 3 mujeres). Los IMC se encontraron elevados: 32% de hombres y 30% de las mujeres con sobrepeso y 2% y 14% obesos respectivamente. Los valores de glucosa, colesterol y triglicéridos fueron altos lo que refleja un aumento en la resistencia a la insulina y anormalidades en los lípidos. Los valores de fosfatasa alcalina se encontraron elevados lo que sugiere que muchos de estos pacientes ciegos padecen osteomalacia ya que permanecen confinados a su hogar. Aunque se ha sugerido que una ingesta adecuada de carotenos y tocoferol están asociadas a ausencia de catarata, ese no fue el caso en la población estudiada. Estudios en el país revelan, sin embargo, la deficiencia altamente prevalente de otras vitaminas tales como la niacina y la riboflavina cuyos efectos protectores en catarata han sido comprobados. En el México moderno por lo tanto, coexisten las deficiencias nutricias, la obesidad, la diabetes incipiente y las alteraciones en los lípidos. Hemos identificado la necesidad de que se inicien investigaciones que apoyen programas preventivos de nutrición a nivel poblacional que pudieran ser implementados paralelamente al tratamiento quirúrgic

Timing of Antiretroviral Therapy and Systemic Inflammation in Sub-Saharan Africa: Results From the META Longitudinal Cohort Study

Chronic inflammation predicts complications in persons with human immunodeficiency virus infection. We compared D-dimer, soluble CD14, and interleukin 6 levels before and 12 months after antiretroviral therapy (ART) initiation, among individuals starting ART during earlier-stage (CD4 T-cell count >350/µL) or late-stage disease (CD4 T-cell count <200/µL). Female sex, older age, viral load, and late-stage disease were associated with pre-ART biomarkers (n = 661; P < .05). However, there were no differences in biomarkers by disease stage after 12 months of ART (n = 438; P > .05), owing to loss from observation and greater declines in biomarkers in late-stage initiators (P < .001). Earlier initiation of ART is associated with decreased inflammation, but levels seem to converge between earlier and later initiators surviving to 12 months