Interactions of heptachlor (a chlorinated hydrocarbon insecticide) and soil microflora

The effect of heptachlor on soil microorganisms was studied under field, greenhouse, and laboratory conditions. Growth of many soil microorganisms was inhibited on culture media containing heptachlor. At a concentration of 25 ppm, heptachlor was bactericidal to 63% of the bacteria tested. Heptachlor, at 100 ppm in agar media used for isolating microorganisms from soil, prevented the development of 89% of the bacteria, 81% of the actinomycetes, and 50% of the fungi that appeared on isolation plates without heptachlor. After heptachlor was added to soil, fungal populations declined and bacterial populations increased. Numbers of bacteria were related to amount of heptachlor added; higher concentrations in soil resulted in larger populations. A selective increase in numbers of fungi which would grow on media containing heptachlor at 100 ppm occurred in soils amended with heptachlor in amounts ordinarily used in field practices (1 Ib./A.), but a similar increase of heptachlor-resistant bacteria occurred only in soils amended with much higher amounts of heptachlor. One bacterium. Bacillus cereus, isolated from soil was found to degrade heptachlor to its parent compound, chlordene

Managing droughts in the low-rainfall areas of the Middle East and North Africa:

Drought is a recurrent and often devastating threat to the welfare of countries in the Middle East and North Africa (MENA) where three-quarters of the arable land has less than 400 mm of annual rainfall, and the natural grazings, which support a majority of the 290 million ruminant livestock, have less than 200 mm. Its impact has been exacerbated in the last half century by the human population increasing yearly at over 3%, while livestock numbers have risen by 50% over the quinquennium. Virtually no scope exists for further expansion of rainfed farming and very little for irrigation, hence there is competition between mechanized cereal production and grazing in the low rainfall areas, and traditional nomadic systems of drought management through mobility are becoming difficult to maintain. Moreover droughts seem to be increasing in frequency, and their high social, economic, and environmental costs have led governments to intervene with various forms of assistance to farmers and herders, including distribution of subsidized animal feed, rescheduling of loans, investments in water development, and in animal health. In this paper we examine the nature and significance of these measures, both with respect to their immediate benefits and costs to the recipients and to governments, and to their longer term impact on poverty and the environment. We conclude that while they have been valuable in reducing catastrophic losses of livestock and thus alleviating poverty, especially in the low rainfall areas where they are the predominant source of income, continued dependence on these programs has sent inappropriate signals to farmers and herders, leading to moral hazards, unsustainable farming practices, and environmental degradation, while generally benefiting the affluent recipients most.Rainfed farming., Environmental impact analysis., Irrigation., Droughts., Middle East., North Africa.,

DESIGNING OF NOVEL TOPICAL IN SITU POLYMERIC FILM-FORMING SOLUTION SPRAY FORMULATION OF ANTIFUNGAL AGENT: IN VITRO ACTIVITY AND IN VIVO CHARACTERIZATION

Objective: Voriconazole (VCZ) is a broad-spectrum antifungal medication that works by inhibiting fungal Cytochrome P450, preventing fungi growth. The current study aims at developing and characterizing an antifungal in situ film-forming polymeric solution spray containing VCZ for use in topical drug delivery systems. Methods: Optimized VCZ in situ polymeric film formulation was evaluated for Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), X-ray diffractometry (XRD), Scanning electron microscope (SEM), in vitro and in vivo, ex-vivo investigation using abdominal rat skin and stability studies. The in vivo antifungal activity of the advanced in situ film was examined in albino Wistar rats. Results: The optimized batch contained 22% Eudragit RS 100 (ERS) and 4% Sorbitol. Based on FTIR, XRD, SEM, and rheological studies. Formulation ingredients of VCZ loaded topical in situ polymeric film spray were observed to be compatible and showed no evidence of precipitation, deformation, or discoloration. Diffusion test (in vitro %), and ex-vivo drug diffusion % obtained 99.22%, and 97.45% respectively. The maximum inhibition zone was measured at 13±0.07 mm. The Wistar rat was employed as an animal model for skin irritation and antifungal studies. A study of short-term stability observed no significant modifications in the physical properties. Conclusion: The findings of the optimized VCZ topical in situ polymeric film spray formulation were satisfactory, demonstrating comparable improvement in superficial antifungal treatment

Interdiffusion of S and Se in Tiemannite

Diffusion coefficients for S-Se interdiffusion in tiemannite (HgSe) single crystals have been determined in the temperature range 500 -700oC. The measured diffusivities may be fit by the equation..

Drag Reducing Agent for Water System Using Natural Polymer (Hibiscus leaves)

The flow of fluid in the pipeline results in frictional energy losses which cause the pressure of the fluid to decrease along the pipeline in the direction of the flow. These will reduce the flow rate of the fluid which is travelling through the pipeline. Therefore, the usage of the drag reducing agents, DRA is important to reduce the frictional resistant in turbulent flow. The elastic property which is also exhibit in hibiscus leaves as well as the commercial DRA, will absorb the energy in the streak which will reduce the turbulence. Thus, the project which the author does for the Final Year Project (FYP) is the drag reducing agent for water injection using natural polymer (hibiscus leaves). This project is to study the effectiveness of hibiscus leaves in reducing the pressure drop and to prove that hibiscus leaves is a potential drag reducing agent to be used in the industry for transporting hydrocarbons in pipeline. It is also a new discovery for cheap alternative to the current commercial DRA in the market as has abundant of resource all over Malaysia. This drag reducing agent is the answer for the problems that arise from the oil and gas industries in the transportation of hydrocarbons. This is an experiment-base project where the author needed to conduct experiment to acquire the valuable data which is needed to prove the effectiveness of the hibiscus leaves as DRA. The experiment that the author performs is to investigate the effectiveness of the hibiscus concentration as DRA. The experiment is conducted by using an open flow test; where water is being pump from the storage tank to the pipeline, and the natural polymer is injected at the injection point into the flow system where it will mix with the flowing water. The flowing water is then travels through the 12.5m galvanized pipe and passes two pressure gauges which is set at different point of the pipe and finally to the outlet point. The pressure at the two points is recorded during the experiment and the drag reduction, flow throughput and flow rate is calculated. From the result of the experiment, it is observed that as the concentration of the hibiscus leaves increases the drag reduction decreases, this shows that the hibiscus leaves is more effective at higher concentration compared to lower concentration. The increase in the drag reduction efficiency prove that hibiscus leave have the potential to be drag reducing agent

DFPI-based Control of the DC-bus Voltage and the AC-side Current of a Shunt Active Power Filter

The current paper presents a continuation of an earlier research and purposes to enhance the performances of the studied system. While the double fuzzy PI (DFPI) control was applied only on the DC capacitor bus in a previous work it is applied here also on the output current of shunt active power filter (SAPF). The nonlinear load disrupts the electrical distribution system by the generation of harmonics, which requires an efficient SAPF intervention to minimize the effects of harmonics on the network and provide electrical energy conforms to International standards. The design and simulation of this work were performed under MATLAB/Simulink environment. The carried-out simulation results demonstrate a satisfactory regulation both for the output current of the SAPF and the DC bus voltage. Furthermore the power quality is improved since a near-unity power factor and very low rates of imbalance of both source voltages and currents are obtained

Reentrant ventricular arrhythmias in the late myocardial infarction period. 12. Spontaneous versus induced reentry and intramural versus epicardial circuits

One to 5 days after one-stage ligation of the left anterior descending coronary artery in dogs, reentrant excitation can be induced by programmed premature stimulation in the surviving electrophysiologically abnormal, thin epicardial layer overlying the infarct. In experiments in four dogs, reentrant excitation occurred “spontaneously” during a regular sinus or atria) rhythm. A tachycardia-dependent Wenckebach conduction sequence in a potentially reentrant pathway was the initiating mechanism for spontaneous reentrant tachycardias and was the basis for both manifest and concealed reentrant extrasystolic rhythms. In all dogs showing spontaneous reentry, reentrant excitation could also be induced by premature stimulation at cycle lengths much shorter than those associated with spontaneous reentry, and induced reentrant circuits were always different from those during spontaneous reentry. In two dogs, the reentrant circuit was located intramurally in close proximity to a patchy septal infarction.The study illustrates that irrespective of the anatomic localization of reentrant circuits (epicardial or intramural), their dimension (large or small) or their mechanism of initiation (programmed premature stimulation or “spontaneous”), reentrant excitation always occurred in a figure 8 configuration (or a modification thereof). The figure 8 model, rather than the ring model or the leading circle model, may be the common model of reentry in the mammalian heart

Risk stratification for arrhythmic events in patients with nonischemic dilated cardiomyopathy and nonsustained ventricular tachycardia: Role of programmed ventricular stimulation and the signal-averaged electrocardiogram

AbstractObjectives. This study investigated prediction of arrhythmic events by the signal-averaged electrocardiogram (ECG) and programmed stimulation in patients with nonischemic dilated cardiomyopathy.Background. Risk stratification in patients with nonischemic dilated cardiomyopathy remains controversial.Methods. Eighty patients with nonischemic dilated cardiomyopathy and spontaneous nonsustained ventricular tachycardia underwent signal-averaged electrocardiography (both time-domain and spectral turbulence analysis) and programmed stimulation. All patients were followed up for a mean of 22 ± 26 months.Results. Sustained monomorphic ventricular tachycardia was induced in 10 patients (13%), who all received amiodarone. The remaining 70 patients were followed up without antiarrhythmic therapy. Of the 80 patients, 15% had abnormal findings on the time-domain signal-averaged ECG, and 39% had abnormal findings on spectral turbulence analysis. Time-domain signal-averaged electrocardiography had a better predictive accuracy for induced ventricular tachycardia than spectral turbulence analysis (88% vs. 66%, p < 0.01). During follow-up, there were 9 arrhythmic events (5 sudden deaths, 4 spontaneous ventricular tachycardia/fibrillation) and 10 nonsudden cardiac deaths. Cox regression analysis showed that no variables predicted arrhythmic events or total cardiac deaths. The 2-year actuarial survival free of arrhythmic events was similar in patients with or without abnormal findings on the signal-averaged ECG or induced ventricular tachycardia.Conclusions. In patients with nonischemic dilated cardiomyopathy, 1) there is a strong correlation between abnormal findings on the time-domain signal-averaged ECG and induced ventricular tachycardia, but both findings are uncommon; and 2) normal findings on the signal-averaged ECG, as well as failure to induce ventricular tachycardia, do not imply a benign outcome