Chlorpyrifos chronic toxicity in broilers and effect of vitamin C

An experiment was conducted to study chlorpyrifos chronic toxicity in broilers and the protective effect of vitamin C. Oral administration of 0.8 mg/kg body weight (bw) (1/50 LD50) chlorpyrifos (Radar®), produced mild diarrhea and gross lesions comprised of paleness, flaccid consistency and slightly enlargement of liver. Histopathologically, chlorpyrifos produced degenerative changes in various organs. Oral administration of 100 mg/kg bw vitamin C partially ameliorated the degenerative changes in kidney and heart. There was insignificant alteration in biochemical and haematological profiles. It is concluded that supplementation of vitamin C reduced the severity of lesions induced by chronic chlorpyrifos toxicity in broilers

Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions. Funding: Bill & Melinda Gates Foundation

High strain rate compression and tension response of high hard tool steel

The cores of armor piercing (APM2) bullets are generally made of high hard (Rc ≈ 60-62) 1070 steel. Tool steel of type AISI O1 is very similar in composition to 1070 steel and can be heat-treated to Rc 60-61. We are conducting a study to generate material model data to numerically simulate the penetration of .30 and .50 caliber M2AP bullets into a variety of ceramic/aluminum/steel ballistic targets. Compression and tension properties of heat treated tool steel are to be presented. The compressive and tensile behavior of AISI O1 tool steel is studied through quasi-static tests, Hopkinson bar experiments and Taylor impact tests. Compressive strength of the heat-treated tool steel increases by a factor of 3 compared to untreated tool steel. Furthermore, experimental data suggest that hard tool steel is strain rate insensitive in tension as well as in compression. However, measured compressive strength (3.5 GPa) and tensile strength (2.5 GPa) at high strain rates (103/s) are different, suggesting that the material behaves almost like a ceramic. A constitutive model for the material is developed based on the experimental data and is used to simulate ballistic penetration into 6061-T6 aluminum and alumina ceramic/aluminum targets

SPALL STRENGTH AND FAILURE WAVES IN GLASS

Une série d'expériences d'impacts de plaques sur des verres sodo-calciques et pyrex a été réalisée, pour étudier les ondes de rupture, récemment mises en évidence par Kancel et al /1/. L'existence de ces ondes est déduite d'observation de figures d'interaction d'ondes et de mesures de contrainte d'écaillage de verres sodo-calciques et pyrex, à l'avant et à l'arrière de ces fronts d'onde. Les verres sodo-calciques et pyrex ont des comportements très différents dans le domaine élastique de compression par choc.We performed a series of plate impact experiments on soda lime and pyrex glasses to investigate failure waves, which have been recently reported by Kanel et al /1/. The existence of these waves is inferred from observations of wave interaction patterns and by measuring spall strength of soda lime glass and pyrex, in front and behind, these wave fronts. Soda lime and pyrex glasses display quite different behavior in the elastic range of shock loading

ELASTIC PRECURSOR DECAY IN CERAMICS AS DETERMINED WITH MANGANIN STRESS GAUGES

Un des paramètres les plus importants pour caractériser le comportement dynamique des matériaux céramiques est la limite élastique d'Hugoniot (LEH) en conditions quasi permanentes. Certains chercheurs ont indiqué une décroissance de la LEH dans les céramiques tandis que d'autres n'ont observé aucune décroissance même pour des éprouvettes relativement épaisses . Nous avons réalisé des essais de choc de plaques avec deux alumines en utilisant des jauges de contrainte au manganin pour enregistrer l'évolution de la contrainte à différentes distances du plan d'impact. Toutes les cibles ont été préparées en usinant des tuiles épaisses pour assurer l'uniformité du matériau. Nous avons trouvé une décroissance du précurseur élastique en fonction de l'épaisseur pour les deux céramiques.One of the most important parameters for characterizing the dynamic behavior of ceramic materials is the steady state Hugoniot Elastic Limit (HEL). Some workers have reported HEL decay in ceramics while others observe no decay even in relatively thick samples. We performed plate impact experiments on two alumina ceramics using manganin stress gauges to monitor the stress histories at different distances away from the impact plane. All targets were prepared by machining thick parent tiles to assure material uniformity. We find that elastic precursor decays with thicknesses in both of the ceramics

BRITTLE FAILURE OF CERAMIC RODS UNDER DYNAMIC COMPRESSION

Des ondes de contrainte ont été générées dans des barres en alumine par un choc de plaque. On a mesuré les contraintes dans les barres à l'aide de jauges au manganin inclues dans la céramique. Quand la contrainte induite par le choc est inférieure à la limite d'élasticité en compression, une onde de contrainte d'amplitude constante parcourt la barre. Quand la contrainte induite dépasse la limite d'élasticité, la contrainte décroît dans la barre avec la distance parcourue et le temps. La décroissance de la contrainte s'explique bien par la détente latérale liée à l'expansion transverse. Ces types d'essais d'impact peuvent être utilisés pour mesurer la limite d'élasticité dynamique. Pour les barres d'alumine, la limite d'élasticité dynamique n'est pas significativement différente des valeurs statiques.Stress waves were induced in alumina ceramic rods by plate impact. Stress in the rods was measured by embedded manganin gauges. When the impact stress is below the compressive yield stress, a constant amplitude stress wave is produced in the rod. When the impact stress exceeds the yield stress, the stress in the rod decays with distance and time. The stress decay is consistant with lateral release involving dilatancy. These types of impact experiments can be used to measure dynamic yield stress. The yield stress in the alumina rods did not differ significantly from static values