Room temperature aqueous Paal–Knorr pyrrole synthesis catalyzed by aluminum tris(dodecyl sulfate)trihydrate

This article reports a novel procedure to prepare pyrroles using a modification of the Paal–Knorr reaction. Water is a safe solvent meeting environmental considerations, but most organic substrates are not soluble in water. A possible solution to improve the solubility of substrates is the use of surface-active reagents that can form micelles. For instance, combined Lewis acid–surfactant catalyst acts both as a Lewis acid to activate the substrate molecules and as a surfactant to form emulsions in water. Here, we prepared and used aluminum tris(dodecyl sulfate)trihydrate to condense various amines to 2,5-hexadione at room temperature. The sole solid pyrrole was separated by a simple filtration. Our findings thus show a novel and improved modification of the Paal–Knorr reaction in terms of mild reaction conditions and clean reaction profiles, using a simple workup procedure and improved yields with excellent chemo-selectivity.     

Quality of drinking water and high incidence rate of esophageal cancer in Golestan province of Iran: a probable link

Golestan province in north Iran is known to be a high-risk area for esophageal cancer (EC). Of a long list of multiple risk factors, this study focuses on a possible link between the epidemiologic patterns of EC and the anomalous concentration of some ions and elements in the drinking water sources. A total of 183 samples from 45 villages covering a wide range of EC mortality rates are collected and analyzed. The results demonstrate that NO₃ ⁻, SO₄ ²⁻, Sb, and Sr exceed the recommended maximum concentration level (MCL) in drinking water. This is more prominent in the villages with high esophageal cancer mortality rate, suggesting a possible link between EC incidence and water quality. Se concentration in drinking water increases from low to the high EC areas, a finding contrary to the expected trend. It is concluded that Se deficiency does not play a major role in the etiology of EC in the Golestan province. The statistical results obtained from Mann–Whitney and Kruskal–Wallis tests along with cluster analysis are consistent with the observed trend of EC mortality rate in Golestan province.     

Grafting of Wool with Alginate Biopolymer/Nano Ag as a Clean Antimicrobial and Antioxidant Agent: Characterization and Natural Dyeing Studies

There is a continuous search for green and sustainable materials and processes in textile dyeing and finishing. In the current study, wool yarns were grafted with Sodium Alginate-Silver nanoparticles (SA-Ag NPs) and consecutively dyed with Cochineal or Madder. The weight gain of the samples was measured to find the optimized SA-Ag NPs initial concentration, and Scanning Electron Microscopy (SEM) was used to study their surface morphology. The effects of the initial dye concentration, pH, temperature on the color strength of the dyed samples were investigated. It was found that the pretreatment enhanced the dye-ability, antimicrobial, and antioxidant characteristics of the samples noticeably. Under the same dyeing conditions, the fixation of dyes on the treated wool fibers was noticeably higher than that of the untreated wool fibers. The colorfastness characteristics of the treated samples dyed with Cochineal or Madder were slightly improved. The results clearly showed that the application of SA-Ag NPs on the wool samples could be considered as a green finishing process with promising antioxidant and antimicrobial activities. A very high level of antimicrobial efficiency (99%) was achieved after the pretreatment, which remained as high as 90% even after ten repeated washing cycles.

     

Evaluation of membrane bioreactor for hypersaline oily wastewater treatment

Produced water is a significant waste stream generated in association with oil and gas production. It contains high concentrations of hydrocarbon constituents and different salts. In this study, a membrane sequencing batch reactor (MSBR) was used to treat synthetic and real produced water. The MSBR was evaluated in terms of biodegradation of hydrocarbons in the synthetic produced water with various organic loading rates (OLR) (0.281, 0.563, 1.124, 2.248, and 3.372 kg COD/(m³ day)), cycle time (12, 24, and 48 h), and membrane performance. The effects of salt concentrations at different total dissolved solids (TDS) (35,000, 50,000, 100,000, 150,000, 200,000, and 250,000 mg/L) on biological treatment of the pollutants in the synthetic and real wastewater were studied. At an OLR of 1.124 kg COD/(m³ day), an HRT of 48 h and TDS of 35,000 mg/L, removal efficiencies of 97.5%, 97.2%, and 98.9% of COD, total organic carbon (TOC), and oil and grease (O&G), respectively were achieved. For the real produced water, removal rates of 86.2%, 90.8%, and 90% were obtained for the same conditions. However, with increasing salt content, the COD-removal efficiencies of the synthetic and real produced water were reduced to 90.4% and 17.7%, respectively at the highest TDS.     

Hepatitis B virus infection among health care workers in Public Teaching Hospitals in Khartoum State, Sudan

Background

Hepatitis B virus (HBV) infection is a global public health problem. It is estimated that there are more than 300 million HBV carriers in the world.

Aim

The study aimed to examine the sero-prevalence of hepatitis B virus (HBV) markers among health care workers (HCWs) in Public Teaching Hospitals in Khartoum State, in the year 2004.

Methods

The study is an observational, cross sectional, facility-based study. It was conducted on stratified two-stage cluster random sample of 843 subjects. The study followed non-parametric statistical methods, using Z-test for single proportion.

Results

Among the 843 subjects tested for all HBV markers (Anti-HBc, HBsAg, HBsAb, and HBeAg), the prevalence of Anti-HBc, HBsAg, HBsAb, and HBeAg was found to be 57% (CI 95%:53-60%), 6% (CI 95%:4.0-8.0%), 37% (CI 95%:34-40%) and 9% (CI 95%:7-11%) respectively. P < 0.05.

Conclusion

Seroprevalence of all HBV markers (P < 0.05) was found to be significantly high, while the rate of immunity against HBV infection was low among health care workers In Public Teaching Hospitals in Khartoum State, Sudan.     

Introducing roadside hazard severity indicator based on evidential reasoning approach

Safety experts have, in recent years, been attentive to roadside accident severity and occurrence. Hitherto, to prioritize road segment hazardousness, there have been little efforts to quantify a well defined indicator. In this regard, the existing indicators are usually very plain and the overall configuration of roadside is rated by experts with an exact number describing its condition. Hence, the uncertainties which come with the subjective judgments cannot be regarded as of any substance. This research contribution therefore presents a procedure to assess the road safety (roadside safety indicator) by means of the evidential reasoning (ER) approach. The betterment of ER as opposed to the available procedures for roadside safety assessment is that the proposed approach makes allowance for the uncertainties which may arise from individual judgments. Additionally, when there is a dearth of evidence concerning factors which affect roadside hazardousness severity to collate several roadside segments, this procedure will offer the benefits of utilizing the maximum/minimum utility function. With the aid of the drawn indicator, organizations and agencies responsible for ensuring road safety can reach more flexible decisions to set in-place uncertain planning and road segments priorities. This indicator can also be utilized as a variable to include roadside conditions in crash severity prediction models. A field case study has also been carried out in an attempt to follow and validate the proposed approach which is based on the run-off accident history for a sample road segments. The crash data confirm the suggested indicator.     

Big data and predictive analytics to optimise social and environmental performance of Islamic banks

Environment Systems and Decisions - Regardless of known as environment-friendly entities, Islamic banks indirectly impact the environment through their clients’ engagement and slow response...     

Evaluation of CMIP5 models and ensemble climate projections using a Bayesian approach: a case study of the Upper Indus Basin,Pakistan

Environmental and Ecological Statistics - The availability of a variety of Global Climate Models (GCMs) has increased the importance of the selection of suitable GCMs for impact assessment studies....     

Effects of microbial inoculations and surfactant levels on biologically- and chemically-assisted phytoremediation of lead-contaminated soil by maize (Zea Mays L.)

Assisted phytoremediation has been widely used for decontamination of potentially toxic elements contaminated soils. A greenhouse experiment was conducted to evaluate the effectiveness of different microbial inoculations and surfactant levels on the phytoremediation of a Pb-polluted calcareous soil by maize. The results showed that application of surfactant increased both root and shoot dry matter yields. Microbial inoculations, however, had no significant effect on the root or shoot dry matter yield. Mean Pb uptake in maize root or shoot increased only following the application of some surfactant levels. Inoculation with microorganisms significantly increased both mean Pb concentration and uptake in maize root but not in maize shoot. Application of 4?mmol surfactant kg?1 along with inoculation with Priformospora indica was effective in increasing Pb phytostabilisation potential. While the application of 2?mmol surfactant kg^?1 along with inoculation with Pseudomonas fluorescens was effective in increasing Pb phytoextraction potential. The fact that the values of translocation efficiencies were low in all treatments, demonstrated the low capability of maize for translocation of Pb from root to shoot. Inoculation with P. fluorescens was the most effective treatment in increasing metal micronutrient uptake. Microbial inoculation and surfactant levels enhanced Pb phytoremediation mostly through phytostabilisation of this metal by maize.     

What are heavy metals? Long-standing controversy over the scientific use of the term ‘heavy metals’ – proposal of a comprehensive definition

The term ‘heavy metals’ is commonly used in the environmental literature to refer to metals and metalloids associated with environmental pollution, toxicity and adverse effects on biota. The term has been diversely defined, mostly in terms of density, relative atomic mass and atomic number. This diversity of definitions has raised questions about the nomenclature of these elements. The inclusion of the metalloid As and the nonmetal Se with heavy metals is also an important issue. Some people have called the term as meaningless, imprecise and poorly defined and have suggested abandoning the use of the term. The term itself may not be problematic but the careless and inconsistent use of terminology has led to a confusion about the meaning of the term. The use of the term may be continued but it should be defined in a more comprehensive and scientific way. Here, a more comprehensive definition of the term ‘heavy metals’ is suggested as ‘naturally occurring metals having atomic number (Z) greater than 20 and an elemental density greater than 5 g cm^?3.’ A screening of the Periodic Table according to this definition yields 51 elements to be called ‘heavy metals.’ As and Se are excluded from heavy metals.