Magnitude of behavioral deficits varies with job-related chlorpyrifos exposure levels among Egyptian pesticide workers.

Chronic occupational exposure to organophosphorus pesticides (OPs) is consistently associated with deficits on behavioral tests when compared to unexposed comparison groups. However, a dose-response relationship has yet to be established, leading some to doubt an association between occupational OP exposure and behavioral deficits. Pesticide application teams in Egypt who are primarily exposed to one OP, chlorpyrifos (CPF), were recruited into a field assessment. Trail Making A and the more challenging Trail Making B tests were administered to 54 engineers (who supervise the pesticide application process, usually from the side of the field), 59 technicians (who guide the pesticide applicators in the field), 31 applicators (who mix and apply pesticides using knapsack sprayers), and 150 controls (who did not work in the fields) at two different times during the OP application season as well as immediately after applications had ended and 1.5 months later. All participants were males since only males work on pesticide application teams in Egypt. Urinary levels of 3,5,6-trichloro-2-pyridinol (TCPy), a specific metabolite of CPF, confirmed the pattern of lower to higher CPF exposures from engineers to technicians to applicators, and these were all greater than urinary metabolite levels in controls. A consistent relationship between job title and performance speed on the behavioral task was observed: Controls had the best (fastest) performance on Trail Making A and B tests throughout the application season, and applicators had significantly slower performance than engineers on Trail Making A (p = 0.015) and B (p = 0.003). However, individual urinary TCPy, blood acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) levels did not predict individual performance. This study identifies a dose-related effect based on job title, which serves as a surrogate for chronic exposure in that differing job titles exhibit varying group exposure levels. The results establish that chronic occupational exposure to chlorpyrifos is neurotoxic and suggest that the classic biomarkers of recent CPF exposure are not predictive of chronic exposure effects

Metabolism of profenofos to 4-bromo-2-chlorophenol, a specific and sensitive exposure biomarker.

Profenofos is a direct acting phosphorothioate organophosphorus (OP) pesticide capable of inhibiting β-esterases such as acetylcholinesterase, butyrylcholinesterase, and carboxylesterase. Profenofos is known to be detoxified to the biologically inactive metabolite, 4-bromo-2-chlorophenol (BCP); however, limited data are available regarding the use of urinary BCP as an exposure biomarker in humans. A pilot study conducted in Egyptian agriculture workers, demonstrated that urinary BCP levels prior to application (3.3-30.0 μg/g creatinine) were elevated to 34.5-3,566 μg/g creatinine during the time workers were applying profenofos to cotton fields. Subsequently, the in vitro enzymatic formation of BCP was examined using pooled human liver microsomes and recombinant human cytochrome P-450s (CYPs) incubated with profenofos. Of the nine human CYPs studied, only CYPs 3A4, 2B6, and 2C19 were able to metabolize profenofos to BCP. Kinetic studies indicated that CYP 2C19 has the lowest Km, 0.516 μM followed by 2B6 (Km=1.02 μM) and 3A4 (Km=18.9μM). The Vmax for BCP formation was 47.9, 25.1, and 19.2 nmol/min/nmol CYP for CYP2B6, 2C19, and 3A4, respectively. Intrinsic clearance (Vmax/Km) values of 48.8, 46.9, and 1.02 ml/min/nmol CYP 2C19, 2B6, and 3A4, respectively, indicate that CYP2C19 and CYP2B6 are primarily responsible for the detoxification of profenofos. These findings support the use of urinary BCP as a biomarker of exposure to profenofos in humans and suggest polymorphisms in CYP 2C19 and CYP 2B6 as potential biomarkers of susceptibility

STR-941: NUMERICAL INVESTIGATION OF REINFORCED CONCRETE BARRIERS SUBJECTED TO BLAST LOADING

People’s lives are threatened by explosions; the tragic terrorist attacks have forced the governments to consider the importance of dealing with these attacks. With the rising threat of terrorism, protecting critical civil infrastructure such as embassies, governmental buildings, and airports against bomb attacks has become a critical issue. In the current research, reinforced concrete barriers subjected to blast loading are numerically investigated using Applied Element Method “AEM”. The blast loads adopts the ASCE guidance for design of blast-resistant buildings in petrochemical facilities. Fully nonlinear dynamic analysis was considered where the barriers thickness and reinforcement, end connections were parametrically investigated. It was found that the thickness and reinforcement of the barriers affect the barriers’ response, where the most significant parameter was the wall thickness

Investigation of The DGs Effect on The Coordination Between Protective Elements in Distribution Network

Addition of Distributed Generators (DGs) to the electric network have more advantages to the network. It improves the voltage profile and the power flow in the network. In the last decade, DGs is used in power system, especially the distribution system. Coordination study for protective devices must be performed on the distribution network with DGs to reach selectivity with minimum clearance time of fault. Due to DG insertion to the electric system, the short circuit level is changed and coordination between protective elements should be done. This paper presents a technique to avoid the miscoordination problem between protective devices due to the impact of DG units insertion without any additional costs. The proposed technique depend on activating and updating the setting of network relays to achieve correct coordination. Also, it doesn\u27t need any additional costs or any additional equipement to be installed in the electric network. This paper make studies on a real radial system of power transformer with its feeders of a 66kV utility substation before and after adding DGs. ETAP software is used to simulate the network under study

Hamilton-Jacobi Quantization Of Continuous Systems With Higher-Order Lagrangian Density

Continuous systems with higher-order Lagrangian density are treated as first order Lagrangian density by using Hamilton-Jacobi method. An example is studied in details

Functionality of Inorganic Nanostructured Materials onto Wool Fabric

Silver nanoparticles (AgNPs) were prepared through chemical reduction method and characterized by UV-Vis absorption spectra to examine its formation with different AgNO3 and sodium borohydride concentrations and by transmission electron microscope (TEM) to evaluate its particle size and size distribution. The wool fabric was first treated separately with AgNPs and titanium dioxide nanoparticles (TiO2NPs) and then dyed with C.I. Acid Orange 74 (AO74). The dye uptake of pre-treated wool fabric with nanoparticles was compared to conventional dyeing of wool. The existence of AgNPs and TiO2NPs on wool fabric during acid dyeing increases the dye uptake up to 27 and 39%, respectively. The dyeing kinetic of wool fabric was positively affected by treating with AgNPs and TiO2NPs. Also, the activation energy of AO74 diffusion was calculated before and after NPs-treatment that confirms the physicsorption dyeing process. The NPs-treatment leads to produce a wool fabric with excellent antibacterial and photocatalytic properties for TiO2NPs-treated wool fabric and very good antibacterial and good photocatalytic properties for AgNPs-treated wool fabric. In addition, NPs-treatment has no adverse effects on fastness properties of the functionalized dyed wool fabric. Keywords: Silver nanoparticles, Titanium dioxide nanoparticles, Wool, Acid dyeing

Behavior of hybrid high-strength fiber reinforced concrete slab-column connections under the effect of high temperature

AbstractConcrete can be modified to perform in a more ductile form by the addition of randomly distributed discrete fibers in the concrete matrix. The combined effect of the addition of two types of fibers (steel fiber and polypropylene fiber with different percentages) to concrete matrix, which is called hybrid effect is currently under investigation worldwide. The current research work presents the conducted experimental program to observe the behavior of hybrid high strength reinforced concrete slab-column connections under the effect of high temperature. For this purpose, ten slab-column connections were casted and tested. The experimental program was designed to investigate the effect of different variables such as concrete mixture, column location and temperature fighting system. All specimens were exposed to a temperature of 500°C for duration of two hours. To observe the effect of each variable, specimens were divided into four groups according to the studied parameters. The test results revealed that using hybrid high strength concrete HFHSC produced more strength in punching failure compared with high strength concrete HSC when exposed to elevated temperature. Fighting by air had higher initial crack load compared with that for without fighting and fighting by water. On the other hand, fighting by water decreased the ultimate load

Physico-mechanical properties and bacterial adhesion of resin composite CAD/CAM blocks : an in-vitro study

The recent introduction of CAD/CAM technology has been strongly impacting the workflow in dental clinics and labs. Among the used CAD/CAM materials, resin composite CAD/CAM blocks offer several advantages. The aim of this study was to evaluate the physic

Reliability assessment for electrical power generation system based on advanced Markov process combined with blocks diagram

This paper presents the power generation system reliability assessment using an advanced Markov process combined with blocks diagram technique. The effectiveness of the suggested methodology is based on HL-I of IEEE_EPS_24_bus. The proposed method achieved the generation reliability and availability of an electrical power system using the Markov chain which based on the operational transition from state to state which represented in matrix. The proposed methodology has been presented for reliability performance evaluation of IEEE_EPS_24_bus. MATLAB code is developed using Markov chain construction. The transition between probability states is represented using changing the failure and repair rates. The reduced number of generation system are used with Markov process to assess the availability, unavailability, and reliability for the generation system. Additionally, the proposed technique calculates the frequency, time duration of states, the probability of generation capacity state which get out of service or remained in service for each state of failure, and reliability indices. A considerable improvement in reliability indices is found with using blocks diagram technique which is used to reduce the infinity number of transition states and assess the system reliability. The proposed technique succeeded at achieving accurate and faster reliability for the power system

Some properties of skew Hurwitz series

In this paper we show that, if R is a ring and σ an endomorphism of R, then the skew Hurwitz series ring T = (HR, σ ) is an n-clean ring if and only if R is an n-clean ring. Moreover, if R is an integral domain and a torsion-free Z-module, then T = (HR, σ ) is a Prufer domain if and only if R is a field. Also, we investigate when the ring T = (HR, σ ) is g(x)-clean, (n, g(x))-clean and a Neat ring