Pesticide residues in fish from the Densu River Basin in Ghana

The Densu River is a typical river flowing through agricultural areas in Southern Ghana. Six fish species from different locations in the river were sampled and analyzed for residues of pesticides and metabolites using GC with ECD/FID. The results of the study indicate that all the detected residues and metabolites in fish samples from the Densu River Basin were organochlorines (OCs). Among the pesticides residues analyzed, DDE, α-endosulfan, γ- HCH, δ- HCH, heptachlor and endosulfan sulphate, were predominant in all the samples. About 50% of the samples recorded positive detection of DDE while α-endosulfan was detected in 60% of the samples. γ- HCH, δ- HCH were detected in 75% and 65% of the samples respectively with heptachlor occurring in 80% of the samples. In almost all the fish species analyzed, DDE was the predominant compound having a mean value of 7.99 μgKg-1. Higher concentrations of pesticide residues were detected in fish samples from the Densu River at Nsawam than the other locations. The total concentration of residues in the fish samples ranged between 0.49 μgKg-1 and 8.90 μgKg-1 with the highest level detected in Hepsetue odoe (HO-N). The sequence of pesticide residues detected in fish samples were HO-N > HN-N > CO-N > CG-N > TZ-N > CN-W > TZ-W > CG-W. The high ratio of DDE/DDT in fish samples (0.1 – 6.9 with a mean of 2.51) indicated probably old input of DDT and significant degradation. The γ -HCH isomer (lindane) was the dominant HCH in fish samples suggesting a preferential usage of lindane (purified γ-HCH) in these areas. The δ-HCH/γ-HCH ratios in most fish samples were low indicating the present input of the pesticide lindane from non-point sources.Keywords: Pesticide residues, Fish, Densu River Basin, Ghana, exposur

A Review of Recent Positron Annihilation NDE Applications

This review will treat two recent applications of positron annihilation to metallurgical studies and will involve the measurement of the Doppler effect associated with the gamma rays emitted during positron annihilation. The applications will be: studies of the interactions of dislocations with pre-precipitates in aged Al-4 weight percent Cu single crystals and studies of the effect of hydrogen charging into polycrystalline nickel

Formation of Oxides in the Interior of Friction Stir Welds

In friction stir welding (FSWing) the actual solid state joining takes place between the faying surfaces which form the weld seam. Thus the seam trace is often investigated for clues when the strength of the weld is reduced. Aluminum and its alloys are known to form a native, protective oxide on the surface. If these native surface oxides are not sufficiently broken up during the FSW process, they are reported to remain in the FSW interior and weaken the bond strength. This type of weld defect has been referred to as a lazy "S", lazy "Z", joint line defect, kissing bond, or residual oxide defect. Usually these defects are mitigated by modification of the process parameters, such as increased tool rotation rate, which causes a finer breakup of the native oxide particles. This study proposes that there may be an alternative mechanism for formation of oxides found within the weld nugget. As the oxidation rate increases at elevated temperatures above 400C, it may be possible for enhanced oxidation to occur on the interior surfaces during the FSW process from entrained air entering the seam gap. Normally, FSWs of aluminum alloys are made without a purge gas and it is unknown how process parameters and initial fit up could affect a potential air path into the interior during the processing. In addition, variations in FSW parameters, such as the tool rotation, are known to have a strong influence on the FSW temperature which may affect the oxidation rate if internal surfaces are exposed to entrained air. A series of FSWs were made in 3 different thickness panels of AA2219 (0.95, 1.27 and 1.56 cm) at 2 different weld pitches. As the thickness of the panels increased, there was an increased tendency for a gap to form in advance of the weld tool. If sufficient air is able to enter the workpiece gap prior to consolidation, the weld temperature can increase the oxidation rate on the interior surfaces. These oxidation rates would also be accelerated in areas of localized liquation. Metallographs from the weld panels showed indications of liquation at the grain boundaries. In FSWs of thicker panels, these regions of liquation were found to be heavily oxidized. The quality of the FSWs was evaluated from tensile testing at room temperature. As the panel thickness increased, a slight decrease in tensile strength was observed which was attributed to the presence of oxides. No oxide formation was observed in the thinner workpieces, although there were indications of localized liquation at the grain boundaries. Results from this study will assist in a better understand of the mechanisms of oxide formation in FSW interiors and provide methodology for minimizing their occurrence

A Statistical Decomposition Based Neural Network For Multivariate Time Series Forecasting

Machine learning based time series forecasting methods are popular and can match the performance of statistical models, in terms of accuracy, scalability, speed, etc. This disclosure presents techniques that incorporate statistical modeling into a neural network framework. The hybrid time series forecasting model described herein is named Seasonality Trend AutoRegressive Residual Yeo-Johnson power transformation Neural Network (STARRY-N). STARRY-N combines the advantages of residual neural network structure (such as N-BEATS) and explainable statistical forecasting models (such as TBATS). The model utilizes a neural network structure with separate stacks for trend, power transformed trend, seasonality, residual correction, and covariate adoption such as holiday effects. STARRY-N has good accuracy and is an explainable forecasting model

Simple elbow dislocations: a systematic review of the literature

Objective: To identify if functional treatment is the best available treatment for simple elbow dislocations. Search strategy: Electronic databases MEDLINE, EMBASE, LILACS, and the Cochrane Central Register of Controlled Trials. Selection criteria: Studies were eligible for inclusion if they were trials comparing different techniques for the treatment of simple elbow dislocations. Data analysis: Results were expressed as relative risk for dichotomous outcomes and weighted mean difference for continuous outcomes with 95% confidence intervals. Main results: This review has included data from two trials and three observational comparative studies. Important data were missing from three observational comparative studies and the results from these studies were extracted for this review. No difference was found between surgical treatment of the collateral ligaments and plaster immobilisation of the elbow joint. Better range of movement, less pain, better functional scores, shorter disability and shorter treatment time were seen after functional treatment versus plaster immobilisation

Quantum Measurement and the Aharonov-Bohm Effect with Superposed Magnetic Fluxes

We consider the magnetic flux in a quantum mechanical superposition of two values and find that the Aharonov-Bohm effect interference pattern contains information about the nature of the superposition, allowing information about the state of the flux to be extracted without disturbance. The information is obtained without transfer of energy or momentum and by accumulated nonlocal interactions of the vector potential $\vec{A}$ with many charged particles forming the interference pattern, rather than with a single particle. We suggest an experimental test using already experimentally realized superposed currents in a superconducting ring and discuss broader implications.Comment: 6 pages, 4 figures; Changes from version 3: corrected typo (not present in versions 1 and 2) in Eq. 8; Changes from version 2: shortened abstract; added refs and material in Section IV. The final publication is available at: http://link.springer.com/article/10.1007/s11128-013-0652-

Repression of btuB gene transcription in Escherichia coli by the GadX protein

<p>Abstract</p> <p>Background</p> <p>BtuB (B twelve uptake) is an outer membrane protein of <it>Escherichia coli</it>, it serves as a receptor for cobalamines uptake or bactericidal toxin entry. A decrease in the production of the BtuB protein would cause <it>E. coli </it>to become resistant to colicins. The production of BtuB has been shown to be regulated at the post-transcriptional level. The secondary structure switch of 5' untranslated region of <it>butB </it>and the intracellular concentration of adenosylcobalamin (Ado-Cbl) would affect the translation efficiency and RNA stability of <it>btuB</it>. The transcriptional regulation of <it>btuB </it>expression is still unclear.</p> <p>Results</p> <p>To determine whether the <it>btuB </it>gene is also transcriptionally controlled by trans-acting factors, a genomic library was screened for clones that enable <it>E. coli </it>to grow in the presence of colicin E7, and a plasmid carrying <it>gadX </it>and <it>gadY </it>genes was isolated. The <it>lacZ </it>reporter gene assay revealed that these two genes decreased the <it>btuB </it>promoter activity by approximately 50%, and the production of the BtuB protein was reduced by approximately 90% in the presence of a plasmid carrying both <it>gadX </it>and <it>gadY </it>genes in <it>E. coli </it>as determined by Western blotting. Results of electrophoretic mobility assay and DNase I footprinting indicated that the GadX protein binds to the 5' untranslated region of the <it>btuB </it>gene. Since <it>gadX </it>and <it>gadY </it>genes are more highly expressed under acidic conditions, the transcriptional level of <it>btuB </it>in cells cultured in pH 7.4 or pH 5.5 medium was examined by quantitative real-time PCR to investigate the effect of GadX. The results showed the transcription of <it>gadX </it>with 1.4-fold increase but the level of <it>btuB </it>was reduced to 57%.</p> <p>Conclusions</p> <p>Through biological and biochemical analysis, we have demonstrated the GadX can directly interact with <it>btuB </it>promoter and affect the expression of <it>btuB</it>. In conclusion, this study provides the first evidence that the expression of <it>btuB </it>gene is transcriptionally repressed by the acid responsive genes <it>gadX </it>and <it>gadY</it>.</p

Protocol for a 20-year follow-up after a randomized controlled trial of a Mediterranean diet in pregnancy:maternal and offspring risk factors for cardiovascular disease

Background: An inadequate maternal diet during pregnancy can impair offspring health and may increase the risk of cardiovascular disease later in life. The purpose of the proposed study is to assess the risk factors associated with cardiovascular disease in both mothers and their offspring 20 years following their participation in a Mediterranean diet intervention trial during pregnancy.Methods: The “Cardiovascular Risk Reduction Diet In Pregnancy” (CARRDIP) study was a randomized controlled trial performed between 1999 and 2001. The participants were randomized to adhere to either a Mediterranean diet or their regular diet during pregnancy. An extensive amount of data such as diet information, ultrasound measurements, anthropometry, and biomarkers from these mothers during pregnancy and their offspring in the neonatal period were collected. The mother–offspring pairs (n = 269) from the CARRDIP study will be invited to participate in a clinical examination and blood sample collection. This follow-up study, conducted 20 years after the original CARRDIP study, will investigate cardiovascular risk factors in mothers and offspring. The primary outcome will be the blood pressure of the offspring. In addition, the study will explore various aspects of cardiovascular health, including metabolic and inflammatory status, clinical history, and body composition of the participants.Discussion: Previous studies investigating the effects of nutrition during pregnancy on maternal and offspring health have been either observational studies, animal studies, or randomized controlled trials with a follow-up period of less than 5 years. This project aims to study the long-term effects of dietary intervention during pregnancy on maternal and offspring cardiovascular risk markers.Clinical Trial Registration: Clinicaltrials.gov, identifier (NCT05030922)