59 research outputs found

    Surface Polaritons in a Semi-infinite Composite Medium using the Bruggeman Dielectric Function

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    Injection safety knowledge and practices among clinical health care workers in Garissa provincial general hospital

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    Background: The World Health Organization estimates that approximately 16 billion injections are administered in developing countries annually. Injection safety is therefore critical in preventing occupational exposure and infection from blood borne pathogens, hence prevention is a vital part of any comprehensive plan for protecting health workers, patients and maintaining a safe environment.Objective: To determine the knowledge and practice of injection safety among clinical healthcare workers at the Garissa Provincial General Hospital.Design: A cross-sectional descriptive study.Setting: The Garissa provincial General Hospital from September 2011 to July 2012.Results: Injection safety knowledge was high with a score of 12.65 (SD ± 2.3) out of the total of 16 items. Appropriate injection safety practices were reported by most of the respondents. The level of knowledge was not significantly associated with respondents’ demographic characteristics(p>0.05), but was significantly associated with hand washing practice(p<0.05).Inferences were made on an appropriate injection safety practices like non-recapping of needles, hand washing and proper waste management. Drug administration practice varied in the different departments (p=0.043) and recapping of needles was significantly associated with training (p=0.047), designation (p=0.02) and area of deployment (p=0.017).Conclusion: Knowledge on injection safety was high but reported and observed practices were below the set standard. Risky practices such as recapping used syringes, re-use of disposable syringes and overfilling of sharp boxes were observed. There was insufficient provision of injection safety equipment, Poor waste handling and inadequate personal protective gear. Over prescription of unnecessary injections was widespread

    Interactions of metal-based engineered nanoparticles with aquatic higher plants : a review of the state of current knowledge

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    The rising potential for the release of engineered nanoparticles (ENPs) into aquatic environments requires evaluation of risks to protect ecological health. The present review examines knowledge pertaining to the interactions of metal-based ENPs with aquatic higher plants, identifies information gaps, and raises considerations for future research to advance knowledge on the subject. The discussion focuses on ENPs' bioaccessibility; uptake, adsorption, translocation, and bioaccumulation; and toxicity effects on aquatic higher plants. An information deficit surrounds the uptake of ENPs and associated dynamics, because the influence of ENP characteristics and water quality conditions has not been well documented. Dissolution appears to be a key mechanism driving bioaccumulation of ENPs, whereas nanoparticulates often adsorb to plant surfaces with minimal internalization. However, few reports document the internalization of ENPs by plants; thus, the role of nanoparticulates' internalization in bioaccumulation and toxicity remains unclear, requiring further investigation. The toxicities of metal-based ENPs mainly have been associated with dissolution as a predominant mechanism, although nano toxicity has also been reported. To advance knowledge in this domain, future investigations need to integrate the influence of ENP characteristics and water physicochemical parameters, as their interplay determines ENP bioaccessibility and influences their risk to health of aquatic higher plants. Furthermore, harmonization of test protocols is recommended for fast tracking the generation of comparable data.M.Thwala acknowledges the UNESCO Keizo Obuchi Fellowship 2014 undertaken at Environmental Toxicology Unit, Clemson University (SC, USA) and the Thuthuka Programme of the National Research Foundation (South Africa). Sponsorship of the present work by the CSIR under the project ―Nanotechnology Risk Assessment in Aquatic Systems: Experimental and Modelling Approaches‖ is also acknowledged.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1552-86182017-07-31hb2016Chemical Engineerin

    Assessment of the effect of nanomaterials on sediment-dwelling invertebrate Chironomus tentans larvae

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    Studies were conducted to determine the effects of a panel of seven nanomaterials (NMs), namely: a-alumina, g-alumina, precipitated silica; silica fume, calcined silica fume, colloidal antimony pentoxide (Sb2O5), and superfine amorphous ferric oxide (Fe2O3), on sediment dwelling invertebrates Chironomus tentans under controlled laboratory conditions. Percentage survival, enzyme activities, growth development, and DNA fragmentation parameters were studied as acute, biochemical, and physiological toxicities of NMs, respectively. Quantitation of catalase and peroxidase enzyme activity demonstrated that toxicant stress of the NMs increased enzyme activity in a concentration dependent fashion across all treatments. The percentage growth length of the test specimens exposed to different NMs was significantly reduced compared to the negative control while only five concentrations were not in the toxic range, namely; Fe2O3 (5 mg/kg); silica fume (5 mg/kg, 50 mg/kg); Sb2O5 (5 mg/kg) and calcined silica fume (5 mg/kg). Genotoxic stress assessed by use of DNA laddering showed complementary findings to the other ecotoxicological endpoints tested in this study—the percentage survival and growth length inhibition.The Parliamentary Grant funding support (No. JNPPG03) from the CSIR (NM, PJO, PJA) as well as the research funding from the University of Pretoria (WWF), University of Limpopo (PKC), University of Stellenbosch (AMB) are acknowledged.http://www.elsevier.com/locate/ecoenvhb2016Chemical EngineeringParaclinical Science

    TiO2 Nanoparticles Are Phototoxic to Marine Phytoplankton

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    Nanoparticulate titanium dioxide (TiO2) is highly photoactive, and its function as a photocatalyst drives much of the application demand for TiO2. Because TiO2 generates reactive oxygen species (ROS) when exposed to ultraviolet radiation (UVR), nanoparticulate TiO2 has been used in antibacterial coatings and wastewater disinfection, and has been investigated as an anti-cancer agent. Oxidative stress mediated by photoactive TiO2 is the likely mechanism of its toxicity, and experiments demonstrating cytotoxicity of TiO2 have used exposure to strong artificial sources of ultraviolet radiation (UVR). In vivo tests of TiO2 toxicity with aquatic organisms have typically shown low toxicity, and results across studies have been variable. No work has demonstrated that photoactivity causes environmental toxicity of TiO2 under natural levels of UVR. Here we show that relatively low levels of ultraviolet light, consistent with those found in nature, can induce toxicity of TiO2 nanoparticles to marine phytoplankton, the most important primary producers on Earth. No effect of TiO2 on phytoplankton was found in treatments where UV light was blocked. Under low intensity UVR, ROS in seawater increased with increasing nano-TiO2 concentration. These increases may lead to increased overall oxidative stress in seawater contaminated by TiO2, and cause decreased resiliency of marine ecosystems. Phototoxicity must be considered when evaluating environmental impacts of nanomaterials, many of which are photoactive

    The satisfactory growth and development at 2 years of age of the INTERGROWTH-21st Fetal Growth Standards cohort support its appropriateness for constructing international standards.

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    BACKGROUND: The World Health Organization recommends that human growth should be monitored with the use of international standards. However, in obstetric practice, we continue to monitor fetal growth using numerous local charts or equations that are based on different populations for each body structure. Consistent with World Health Organization recommendations, the INTERGROWTH-21st Project has produced the first set of international standards to date pregnancies; to monitor fetal growth, estimated fetal weight, Doppler measures, and brain structures; to measure uterine growth, maternal nutrition, newborn infant size, and body composition; and to assess the postnatal growth of preterm babies. All these standards are based on the same healthy pregnancy cohort. Recognizing the importance of demonstrating that, postnatally, this cohort still adhered to the World Health Organization prescriptive approach, we followed their growth and development to the key milestone of 2 years of age. OBJECTIVE: The purpose of this study was to determine whether the babies in the INTERGROWTH-21st Project maintained optimal growth and development in childhood. STUDY DESIGN: In the Infant Follow-up Study of the INTERGROWTH-21st Project, we evaluated postnatal growth, nutrition, morbidity, and motor development up to 2 years of age in the children who contributed data to the construction of the international fetal growth, newborn infant size and body composition at birth, and preterm postnatal growth standards. Clinical care, feeding practices, anthropometric measures, and assessment of morbidity were standardized across study sites and documented at 1 and 2 years of age. Weight, length, and head circumference age- and sex-specific z-scores and percentiles and motor development milestones were estimated with the use of the World Health Organization Child Growth Standards and World Health Organization milestone distributions, respectively. For the preterm infants, corrected age was used. Variance components analysis was used to estimate the percentage variability among individuals within a study site compared with that among study sites. RESULTS: There were 3711 eligible singleton live births; 3042 children (82%) were evaluated at 2 years of age. There were no substantive differences between the included group and the lost-to-follow up group. Infant mortality rate was 3 per 1000; neonatal mortality rate was 1.6 per 1000. At the 2-year visit, the children included in the INTERGROWTH-21st Fetal Growth Standards were at the 49th percentile for length, 50th percentile for head circumference, and 58th percentile for weight of the World Health Organization Child Growth Standards. Similar results were seen for the preterm subgroup that was included in the INTERGROWTH-21st Preterm Postnatal Growth Standards. The cohort overlapped between the 3rd and 97th percentiles of the World Health Organization motor development milestones. We estimated that the variance among study sites explains only 5.5% of the total variability in the length of the children between birth and 2 years of age, although the variance among individuals within a study site explains 42.9% (ie, 8 times the amount explained by the variation among sites). An increase of 8.9 cm in adult height over mean parental height is estimated to occur in the cohort from low-middle income countries, provided that children continue to have adequate health, environmental, and nutritional conditions. CONCLUSION: The cohort enrolled in the INTERGROWTH-21st standards remained healthy with adequate growth and motor development up to 2 years of age, which supports its appropriateness for the construction of international fetal and preterm postnatal growth standards

    Bioaccumulation and ecotoxicity of carbon nanotubes

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    Carbon nanotubes (CNT) have numerous industrial applications and may be released to the environment. In the aquatic environment, pristine or functionalized CNT have different dispersion behavior, potentially leading to different risks of exposure along the water column. Data included in this review indicate that CNT do not cross biological barriers readily. When internalized, only a minimal fraction of CNT translocate into organism body compartments. The reported CNT toxicity depends on exposure conditions, model organism, CNT-type, dispersion state and concentration. In the ecotoxicological tests, the aquatic organisms were generally found to be more sensitive than terrestrial organisms. Invertebrates were more sensitive than vertebrates. Single-walled CNT were found to be more toxic than double-/multi-walled CNT. Generally, the effect concentrations documented in literature were above current modeled average environmental concentrations. Measurement data are needed for estimation of environmental no-effect concentrations. Future studies with benchmark materials are needed to generate comparable results. Studies have to include better characterization of the starting materials, of the dispersions and of the biological fate, to obtain better knowledge of the exposure/effect relationships
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