Perfil de exposición ocupacional a polvo de cemento y sílice cristalina en procesos de cementación y Fracturamiento hidráulico en el sector Oil & Gas en Colombia: un estudio retrospectivo (2009 – 2013).

La exposición a polvo de cemento y sílice ha sido estudiada por años en países como Estados Unidos y Canadá, cuando el polvo de cemento se inhala durante diferentes actividades, se puede ocasionar afectación del tracto respiratorio de las personas expuestas. El estudio “Perfil de exposición ocupacional a polvo de cemento y sílice cristalina en procesos de cementación y Fracturamiento hidráulico en el sector Oil & Gas en Colombia: un estudio retrospectivo (2009 – 2013).” Permitió identificar las actividades funcionales que representan un riesgo potencial por la presencia de partículas aerosuspendidas, analizar una base de datos que reúne cerca de 18298 registros de evaluaciones higiénicas en el sector Oil & Gas, realizar posteriormente el cálculo de material particulado en la fracción respirable y sílice cristalina aplicables para cada proceso y el procesamiento de los datos estadísticamente, confrontar estos estimadores estadísticos con los valores límites permisibles definidos por el gobierno nacional, los resultados incluyeron la caracterización de un perfil de exposición ocupacional por actividad funcional para el proceso de cementación, la identificación de los trabajadores más expuestos según las condiciones de exposición y cuáles de estos perfiles superan los límites máximos permisibles para un turno de trabajo de 12 horas, esta información permitirá a los profesionales de la salud e higiene laboral orientar actividades de seguimiento, vigilancia y control en los grupos de exposición similar específicos. Para el proceso de fracturamiento hidráulico los datos encontrados no fueron estadísticamente significativos.

Alteraciones en el material genético de pintores de carros expuestos a solventes orgánicos en una localidad de Bogotá

Los solventes orgánicos son sustancias químicas que por sus propiedades físico-químicas son fácilmente inhalados o absorbidos por la piel, pueden causar daños de diversa índole en la salud. En Colombia existen normas que contemplan las medidas de protección, sin embargo persiste la informalidad en el sector de pintores de autos, por lo cual los trabajadores expuestos, a largo plazo pueden ver afectada su salud. En este estudio se analizó la relación entre individuos expuestos laboralmente a los solventes orgánicos versus no expuestos con respecto a la longitud de sus telómeros y formación de fragilidades. Se emplearon muestras de sangre extraídas por venopunción, recolectada en dos tubos: uno con Heparina, destinado al cultivo de linfocitos, para obtener cromosomas metafásicos y evaluar en ellos la presencia de fragilidades; el otro tubo con EDTA, fue empleado para la extracción de ADN y se utilizó para obtener los valores de longitud telomérica mediante la técnica de PCR cuantitativa. Los análisis estadísticos se realizaron aplicando la prueba de rangos de Wilcoxon, en el caso de la presencia de fragilidades se analizó la razón No.Fragilidades/No.Metafases, aplicando el método de Wilcoxon se encontró que existe diferencia estadísticamente significativa entre expuestos y no expuestos (p = 0,036), en donde los expuestos presentan mayor frecuencia de fragilidades. Por otra parte el valor relativo de longitud telomérica del grupo de expuestos fue mayor que el observado en el grupo de no expuestos, esta diferencia fue estadísticamente significativa (Wilcoxon, p = 0.002).

Factors affecting biological control effectiveness of Pasteuria penetrans in Meloidogyne javanica and the bacterial development in the nematode body

The invasion and infectivity of Meloidogyne javanica juveniles (J2) encumbered with spore of Pasteuria Penetrans were influenced by the temperature and the time J2 were in the soil before exposure to roots. The percentage of infected females decreased as the time juveniles spent in soil increased. When spore encumbered J2 were maintained at 30 degrees C the decrease in infection was greater than that at 18 degrees C. The thermal time requirements and the base temperature for P. penetrans development were estimated. The rate of development followed an exponential curve between 21 and 36 degrees C and the base temperature for development was estimated by extrapolation to be 18.5 degrees C. The effect of integrating a nematode resistant tomato cultivar with the biocontrol agent P. penetrans also was investigated. The ability of the biocontrol agent to reduce numbers of root-knot nematodes was dependent on the densities of the nematode and P. penetrans spores in the soil.

Spatial and management factors associated with exposure of smallholder dairy cattle in Tanzania to tick-borne pathogens

A cross-sectional study of serum antibody responses of cattle to tick-borne pathogens (Theileria parva, Theileria mutans, Anaplasma marginale, Babesia bigemina and Babesia bovis) was conducted on smallholder dairy farms in Tanga and Iringa Regions of Tanzania. Seroprevalence was highest for T. parva (48% in Iringa and 23% in Tanga) and B. bigemina (43% in Iringa and 27% in Tanga) and lowest for B. bovis (12% in Iringa and 6% in Tanga). We use spatial and non-spatial models, fitted using classical and Bayesian methods, to explore risk factors associated with seroprevalence. These include both fixed effects (age, grazing history and breeding status) and random effects (farm and local spatial effects). In both regions, seroprevalence for all tick-borne pathogens increased significantly with age. Animals pasture grazed in the 3 months prior to the start of the sampling period were significantly more likely to be seropositive for Theileria spp. and Babesia spp. Pasture grazed animals were more likely to be seropositive than zero-grazed animals for A. marginale, but the relationship was weaker than that observed for the other four pathogens. This study did not detect any significant differences in seroprevalence associated with other management-related variables, including the method or frequency of acaricide application. After adjusting for age, there was weak evidence of localised (< 5 km) spatial correlation in exposure to some of the tick borne diseases. However, this was small compared with the 'farm-effect', suggesting that risk factors specific to the farm were more important than those common to the local neighbourhood. Many animals were seropositive for more than one pathogen and the correlation between exposure to the different pathogens remained after adjusting for the identified risk factors. Identifying the determinants of exposure to multiple tick-borne pathogens and characterizing local variation in risk will assist in the development of more effective control strategies for smallholder dairy farms. (c) 2005 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Underarm cosmetics and breast cancer

Although risk factors are known to include the loss of function of the susceptibility genes BRCA1/BRCA2 and lifetime exposure to oestrogen, the main causative agents in breast cancer remain unaccounted for. It has been suggested recently that underarm cosmetics might be a cause of breast cancer, because these cosmetics contain a variety of chemicals that are applied frequently to an area directly adjacent to the breast. The strongest supporting evidence comes from unexplained clinical observations showing a disproportionately high incidence of breast cancer in the upper outer quadrant of the breast, just the local area to which these cosmetics are applied. A biological basis for breast carcinogenesis could result from the ability of the various constituent chemicals to bind to DNA and to promote growth of the damaged cells. Multidisciplinary research is now needed to study the effect of long-term use of the constituent chemicals of underarm cosmetics, because if there proves to be any link between these cosmetics and breast cancer then there might be options for the prevention of breast cancer. Copyright D 2003 John Wiley Sons, Ltd.

Combining physical, cultural and biological methods: prospects for integrated non-chemical weed management strategies

Physical, cultural and biological methods for weed control have developed largely independently and are often concerned with weed control in different systems: physical and cultural control in annual crops and biocontrol in extensive grasslands. We discuss the strengths and limitations of four physical and cultural methods for weed control: mechanical, thermal, cutting, and intercropping, and the advantages and disadvantages of combining biological control with them. These physical and cultural control methods may increase soil nitrogen levels and alter microclimate at soil level; this may be of benefit to biocontrol agents, although physical disturbance to the soil and plant damage may be detrimental. Some weeds escape control by these methods; we suggest that these weeds may be controlled by biocontrol agents. It will be easiest to combine biological control with. re and cutting in grasslands; within arable systems it would be most promising to combine biological control (especially using seed predators and foliar pathogens) with cover-cropping, and mechanical weeding combined with foliar bacterial and possibly foliar fungal pathogens. We stress the need to consider the timing of application of combined control methods in order to cause least damage to the biocontrol agent, along with maximum damage to the weed and to consider the wider implications of these different weed control methods.

Visual exposure impacts on toddlers' willingness to taste fruits and vegetables

This study explores the effects of exposure to pictures of fruits and vegetables on young children's willingness to taste the foods. The parents of 20 toddlers aged 21-24 months were asked to read a picture book about four foods with their child every day for two weeks. in a subsequent 'taste test' children displayed a neophobic pattern of behaviour towards foods to which they had not been exposed, but not towards exposed foods. Furthermore, while exposure served to decrease children's willingness to taste familiar vegetables, it increased their willingness to taste unfamiliar fruits. (C) 2009 Elsevier Ltd. All rights reserved.

Action observation and robotic agents: learning and anthropomorphism

The ‘action observation network’ (AON), which is thought to translate observed actions into motor codes required for their execution, is biologically tuned: it responds more to observation of human, than non-human, movement. This biological specificity has been taken to support the hypothesis that the AON underlies various social functions, such as theory of mind and action understanding, and that, when it is active during observation of non-human agents like humanoid robots, it is a sign of ascription of human mental states to these agents. This review will outline evidence for biological tuning in the AON, examining the features which generate it, and concluding that there is evidence for tuning to both the form and kinematic profile of observed movements, and little evidence for tuning to belief about stimulus identity. It will propose that a likely reason for biological tuning is that human actions, relative to non-biological movements, have been observed more frequently while executing corresponding actions. If the associative hypothesis of the AON is correct, and the network indeed supports social functioning, sensorimotor experience with non-human agents may help us to predict, and therefore interpret, their movements.

Terahertz spectroscopy and imaging at the nanoscale for biological and security applications

The chemical specificity of terahertz spectroscopy, when combined with techniques for sub-wavelength sensing, is giving new understanding of processes occurring at the nanometre scale in biological systems and offers the potential for single molecule detection of chemical and biological agents and explosives. In addition, terahertz techniques are enabling the exploration of the fundamental behaviour of light when it interacts with nanoscale optical structures, and are being used to measure ultrafast carrier dynamics, transport and localisation in nanostructures. This chapter will explain how terahertz scale modelling can be used to explore the fundamental physics of nano-optics, it will discuss the terahertz spectroscopy of nanomaterials, terahertz near-field microscopy and other sub-wavelength techniques, and summarise recent developments in the terahertz spectroscopy and imaging of biological systems at the nanoscale. The potential of using these techniques for security applications will be considered.

The lethal and sub-lethal consequences of entomopathogenic nematode infestation and exposure for adult pine weevils, Hylobius abietis (Coleoptera: Curculionidae)

Entomopathogenic nematodes (EPN) frequently kill their host within 1–2 days, and interest in EPN focuses mainly on their lethality. However, insects may take longer to die, or may fail to die despite being infected, but little is known about the effects of EPN infection on insects, other than death. Here we investigate both lethal and sub-lethal effects of infection by two EPN species, Steinernema carpocapsae and Heterorhabditis downesi, on adults of the large pine weevil, Hylobius abietis. Following 12 h nematode–weevil contact in peat, S. carpocapsae killed a significantly higher proportion of weevils (87–93%) than H. downesi (43–57%) at all concentrations tested. Less than 10% of weevils were dead within 2 days, and weevils continued to die for up to 10 days after exposure (LT50 of 3 days or more). In a separate experiment, live weevils dissected 6 days after a 24 h exposure to nematodes on filter paper harbored encapsulated and dead nematodes, showing that weevils could defend themselves against infection. Some live weevils also harbored live nematodes 6 days after they had been removed from the nematode infested medium. Feeding by weevils was not affected by infection with, or exposure to, either species of EPN. We discuss these results in relation to the use of EPN in biological control against H. abietis.

Maternal postnatal depression predicts altered offspring biological stress reactivity in adulthood

The offspring of depressed parents have been found to show elevated basal levels of the stress hormone cortisol. Whether heightened cortisol stress reactivity is also present in this group has yet to be clearly demonstrated. We tested whether postnatal maternal depression predicts subsequent increases in offspring biological sensitivity to social stress, as indexed by elevated cortisol reactivity. Participants (mean age 22.4-years) derived from a 22-year prospective longitudinal study of the offspring of mothers who had postnatal depression (PND group; n=38) and a control group (n=38). Salivary cortisol response to a social-evaluative threat (Trier Social Stress Test) was measured. Hierarchical linear modelling indicated that PND group offspring showed greater cortisol reactivity to the stress test than control group participants. Group differences were not explained by offspring depressive or anxiety symptoms, experiences of negative life events, elevated basal cortisol at age 13-years, subsequent exposure to maternal depression, or other key covariates. The findings indicate that the presence of early maternal depression can predict offspring biological sensitivity to social stress in adulthood, with potential implications for broader functioning.