Piscicidal Effects of Terminalia arjuna Leaf, Bark and Fruit Extract on a Fresh Water Predatory Catfish, Heteropneustes fossilis

Piscicidal effects of several solvent extarcts (distilled water, 50% ethanol, absolute ethanol and 80% methanol) of Terminalia arjuna leaves, barks and fruits were studied against a common fresh water predatory fish, Heteropneustes fossilis under laboratory conditions in terms of Behavior and mortality of fishes after 24 h. Fishes exposed to plant extracts showed agitating movement with quick surfacing, loss of balance, mucus secretion, and finally died. The LC50 values of distilled water, 50% ethanol, absolute ethanol and 80% methanol extracts were found to be 311.726, 236.141, 183.541, 478.794 ppm for leaves, 117.894, 96.998, 38.990, 304.193 ppm for barks and 1400.033, 949.209, 555.201, 875.158 ppm for fruits, respectively. Chi-square values were found to be insignificant at P0.01. Based on LC50 values, order of piscicidal activity followed the pattern, bark > leaf > fruit extracts. Order of piscicidal activity for the extracts was like absolute ethanol > 50% ethanol > distilled water > 80% methanol for leaf and bark, while for fruit extracts, trend was like absolute ethanol > 80% methanol > 50% ethanol > distilled water

Heavy metals leaching behaviour assessment of palm oil clinker

Technical benefit of incorporation of Palm Oil Clinker (POC) in cement-based applications has been proven in recent studies. The aim of this work was to assess the heavy metal leaching behavior to ensure environmental safety of using POC in cement-based applications. The chemical composition, morphology, total organic carbon (TOC) and mineralogy were determined using XRF, FESEM, TOC analyzers and XRD to select appropriate chemical reagents for complete digestion. HNO3, HF and HClO4 were used for digestion of POC to measure heavy metal content using ICP-MS. The chemical reagents CH3COOH, NH2OH-HCl, H2O2+CH3COONH4 and HF+HNO3+HCl were used for extraction of acid soluble, reducible, oxidizable and residual fractions of heavy metals in POC, respectively. The leaching toxicity of the POC was investigated by the USEPA 1311 TCLP method. The result showed the presence of Be, V, Cr, Ni, Cu, Zn, As, Se, Ag, Cd, Ba and Pb with levels of 5.13, 11.02, 2.65, 1.93, 45.43, 11.84, 15.07, 0, 0, 81.97 and 1.76 mg/kg, respectively, in POC. The leaching value in mg/L of As (4.56), Cu(1.05), Be (0.89), Zn(0.51), Ba(0.26), Ni (0.17), V(0.15), Cr(0.001) and Se (0.001) is found well below the standard limit of risk. Risk assessment code (RAC) analysis confirms the safe incorporation of POC in cement-based applications

Toward polymer composites based and architectural engineering induced flexible electrodes for lithium-ion batteries

Recently, polymers, especially conducting (CPs) and non-conducting polymers (nCPs), have been emerged as the promising flexible electrode components for lithium-ion batteries due to their inherent high mechanical tolerance limit, excellent thermal and chemical stability, low density, ease of processing, low cost, and versatility. In addition, CPs provide good electrical conductivity. Polymeric structures remain almost the same even after hundreds to thousands of electrochemical cycles. However, some crucial factors, such as low conductivity, energy density, and rate performance, often limit the large-scale exploitation of these polymers. Although CPs, and nCPs can provide the desired flexibility, nCPs, in particular, increase the ‘dead volume’ of electrodes. In this context, it is necessary to resolve the issues existing with the polymers to make them effective confinement matrices for flexible electrodes. On the other hand, customizing the electrode architectures is vital for achieving multidirectional flexibility without compromising energy density and overall capacity. However, low active materials loading and deviation from the customized structures after several deformation cycles still affect the desired performance in terms of electrochemical and mechanical. Furthermore, the intricate and costly preparation processes of customized electrodes are the major bottlenecks toward practical applications. This review discusses the recent progress, merits, and demerits of the most widely studied polymer composites-based and architectural engineering induced flexible electrodes for lithium-ion batteries (LIBs). Both CPs and nCPs are discussed in the perspectives of current research status, major limitations, key factors associated with electrochemical performances and future outlook of the developments on polymer-based flexible electrodes

Genetically Engineered Strains: Application and Advances for 1,3-Propanediol Production from Glycerol

Propilen je jedan od najvažnijih kemijskih spojeva što se koriste za sintezu nekih komercijalnih proizvoda, poput kozmetičkih i prehrambenih proizvoda, maziva i lijekova. Iako se može proizvesti kemijskim procesom i biosintezom, biosinteza propilena je ekonomičnija, ekološki prihvatljivija i jednostavnija. Propilen se može sintetizirati transformacijom glicerola ili sličnog supstrata s pomoću bakterija kao što su Clostridium butyricum i Klebsiella pneumoniae. Međutim, moguće zapreke primjeni mikroorganizama su loša produktivnost i usporavanje procesa zbog nastanka međuprodukata. Da bi se ti problemi izbjegli, posljednja istraživanja fokusiraju se na razvoj novih sojeva modifikacijom genoma različitim metodama, poput mutageneze i genetičkog inženjerstva. Primjenom genetički modificiranih sojeva dobivenih različitim postupcima postignut je bolji prinos, te su izbjegnuti neki problemi prisutni u proizvodnji propilena s pomoću divljih tipova bakterija. U ovom su radu prikazana nova postignuća u razvoju tehnologija proizvodnje genetički modificiranih mikroorganizama za primjenu u biosintezi propilena.1,3-Propanediol (1,3-PD) is one of the most important chemicals widely used as monomers for synthesis of some commercially valuable products, including cosmetics, foods, lubricants and medicines. Although 1,3-PD can be synthesized both chemically and biosynthetically, the latter offers more merits over chemical approach as it is economically viable, environmentally friendly and easy to carry out. The biosynthesis of 1,3-PD can be done by transforming glycerol or other similar substrates using some bacteria, such as Clostridium butyricum and Klebsiella pneumoniae. However, these natural microorganisms pose some bottlenecks like low productivity and metabolite inhibition. To overcome these problems, recent research efforts have been focused more on the development of new strains by modifying the genome through different techniques, such as mutagenesis and genetic engineering. Genetically engineered strains obtained by various strategies cannot only gain higher yield than wild types, but also overcome some of the barriers in production by the latter. This review paper presents an overview on the recent advances in the technological approaches to develop genetically engineered microorganisms for efficient biosynthesis of 1,3-PD

Electrocatalytic and structural properties and computational calculation of PAN-EC-PC-TPAI-I2 gel polymer electrolytes for dye sensitized solar cell application

In this study, gel polymer electrolytes (GPEs) were prepared using polyacrylonitrile (PAN) polymer, ethylene carbonate (EC), propylene carbonate (PC) plasticizers and different compositions of tetrapropylammonium iodide (TPAI) salt. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) measurements were done using non-blocking Pt-electrode symmetric cells. The limiting current (Jlim), apparent diffusion coefficient of triiodide ions ðD* I3 Þ and exchange current were found to be 12.76 mA cm2 , 23.41 107 cm2 s 1 and 11.22–14.24 mA cm2 , respectively, for the GPE containing 30% TPAI. These values are the highest among the GPEs with different TPAI contents. To determine the ionic conductivity, the EIS technique was employed with blocking electrodes. The GPE containing 30% TPAI exhibited the lowest bulk impedance, Rb (22 U), highest ionic conductivity (3.62 103 S cm1 ) and lowest activation energy. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques were utilized for structural characterization. Functional group interactions among PAN, EC, PC and TPAI were studied in the FTIR spectra of the GPEs. An up-shift of the XRD peak indicates the polymer–salt interaction and possible complexation of the cation (TPA+ ion) with the lone pair of electrons containing site –C^N at the N atom in the host polymer matrix. On the other hand, computational study shows that TPAI-PAN based GPE possesses the lowest frontier orbital bandgap, which coincided with the enhanced electrochemical and electrocatalytic performance of GPE. The dyesensitized solar cell (DSSC) fabricated with these GPEs showed that the JSC (19.75 mA cm2 ) and VOC (553.8 mV) were the highest among the GPEs and hence the highest efficiency, h (4.76%), was obtained for the same electrolyte

Rechargeable metal-metal alkaline batteries : Recent advances, current issues and future research strategies

Over the past few decades, remarkable advancement has been attained in the field of rechargeable metal–metal alkaline batteries (RABs). In terms of safety, energy density, charge-discharge capacity, and long-term storage capability, metal-metal RABs (e.g., Ni–Zn, Ni–Fe, Ni–Bi, Ni–MH, Ag–Zn, Co–Zn, Cu–Zn, and Bi–Zn systems) are contemplated as the promising energy storage devices for the applications in electric vehicles (EVs), hybrid EVs, grid-scale energy storage, as well as various implantable and wearable electronic devices. Especially, Ni-MH batteries become competitive with Li-ion batteries for EVs and hybrid EVs applications due to their high tolerance against mechanical abuse, stability under wide temperature ranges, and considerable charge/discharge capacity. Meanwhile, earlier works reviewed only specific topics, so, as a rapidly growing research topic, providing a deep understanding on metal–metal RABs is timely and worthwhile. So, in this work, we discuss the electrochemistry of all metal-metal RABs, then full cell designing with their performance will be discussed thoroughly. Further, issues associated with the existing metal–metal RABs and corresponding impro

A comparative study on normal and high sugary corn genotypes for evaluating raw material quality and enzyme consumption during dry-grind ethanol production / Md Zabed Hossain

Agronomic and biochemical characteristics of four high sugary corn genotypes (HSGs) and four parent field corn lines (PFCs) were determined to evaluate raw material quality. Subsequently, the effects of kernel sugars on the enzyme requirements, fermentable sugar and ethanol yield, and co-product quality were investigated. Major agronomic characteristics differed among the corn genotypes. Sugar accumulation in the kernels showed a negative correlation with flowering time (FT), grain filling period (GFP) and black layer maturity (BLM). These findings showed that the genotypes exhibiting lower FT, GFP and BLM would have higher amounts of sugars. HSGs contained higher amounts of total soluble sugars (TSS) and lower amounts of starch than the respective PFCs. As a result, a significant negative correlation was observed between kernel starch and sugar content. TSS content in HSGs ranged between 4.43-6.72% in 2012 and 4.64-7.47% in 2013, while it varied in PFCs between 0.76%-1.36% in 2012 and 0.85-1.27% in 2013. Kernel starch ranged between 66.34-69.85% in HSGs and 67.37-72.08% in PFCs in 2012, and 65.89-70.41% in HSGs and 68.69-73.61% in PFCs in 2013. Conventional hydrolysis under four enzyme loads showed that HSGs produced optimum concentration of reducing sugars (RS) while consuming an enzyme load of 3.0 kg/MT, whereas PFCs required 4.0 kg/MT for maximum sugar yield. Conventional fermentation was conducted by simultaneous saccharification and fermentation (CSSF) technique using an initial solid load 250 g/L. Ethanol concentration varied between 98.7-112.5 g/L in HSGs and 80.8-86.8 g/L in PFCs when enzyme load was 3.0 kg/MT. As the enzyme load increased to 4.0 kg/MT, ethanol concentration reached 102.3-113.1 g/L in HSGs and 85.1-99.5 g/L in PFCs. During granular starch hydrolysis (GSH), RS yield in HSGs did not vary significantly above the enzyme load 1.5 kg/MT, while for the PFCs it did not show a significant increase above a higher enzyme load, ranging between 2.0 and 2.5 kg/MT. The final ethanol concentration after granular starch hydrolysis and simultaneous fermentation (GSHSF) with an initial solid load 300 g/L, ranged from 15.25% to 17.5% (v/v) in HSGs and 11.66% to 13.65% in PFCs at the enzyme load 1.5 kg/MT. Ethanol concentration increased to 16.49–17.94% in HSGs and 14.32–16.85% in PFCs as the enzyme load increased to 2.0 kg/MT. Ethanol concentration showed a negative correlation with kernel starch, whereas, a positive correlation was observed between kernel sugars and ethanol yield. The average yield of distiller’s dried grains with soluble (DDGS) among the corn genotypes ranged from 25.07% to 32.44% for CSSF and 26.97% to 31.69% for GSHSF. Among the biochemical components in DDGS, starch content varied significantly between PFCs and HSGs, and the two enzyme doses used for fermentation. Other components in DDGS for both HSGs and PFCs were well within the values reported in the literature. In conclusion, the study has shown that higher kernel sugar in the corn genotypes is able to improve raw material quality for dry-grind ethanol production as it has the potential to reduce enzyme consumption and produce enhanced amounts of ethanol

Bioremediation of Arsenic: Prospects and Limitations in the Agriculture of Bangladesh

Arsenic contamination in the groundwater of Bangladesh has been termed as one of the largest mass poisoning in history. The problem of arsenic toxicity in crop plants that occurs through transfer of arsenic from contaminated soil to plant parts is of great concern because of its potential health hazards. Among the various method, bioremediation of arsenic is the most desirable because of low coast, environmental safety and sustainability. This article focuses on the potential of using various methods for arsenic bioremediation and discusses the advantages and challenges of these methods with special emphasis on the problem of Bangladesh. Although remediation through phytoextraction of arsenic in soil seems promissing, disposing plants used as hyper-accumulator is a concern for the environment. Moreover, further improvement of phytoextraction is needed due to the severity of arsenic contamination in the agricultural soils of Bangladesh. Using soil microbes for bioremediatioin also needs further research in order to enhance our knowledge abut the efficient methods suitable for Bangladesh. Information gathered in this article is likely to enhance our knowledge about the arsenic bioremediation among the stakeholders including the policy makers in countries like Bangladesh where the problem of arsenic contamination in agricultural soil is severe

PESTICIDE DEMAND AMONG HYBRID VEGETABLE AND CEREAL SEED PRODUCERS IN BANGLADESH: A SIMULTANEOUS EQUATION ANALYSIS

Demand for pesticides, inorganic and organic fertilizers were jointly estimated using survey data from a randomly selected 81 BRAC `contract hybrid vegetables and cereal seed growers' in northwestern Bangladesh applying a simultaneous equation framework. Pesticide cost accounts for 6.9% of the gross value of output in hybrid seeds of vegetables and 3.2% in cereals. About 87% of farmers used pesticides at least once with mean number of application of 4.4 times. Twenty-seven brands of pesticides were used including a substantial number of banned pesticides. Price elasticity of demand for pesticides, fertilizers and biofertilizers were estimated at -0.83, -0.21 and -1.13, respectively. Farmers treat chemical fertilizers and pesticides as complements. Increase in prices of both vegetable and cereal seeds significantly increases pesticide demand. Farmers who use mask as a precaution during pesticide application apply significantly higher amount of all three inputs. Farmers' level of education and experience significantly reduce pesticide use. Major thrust for pesticides regulation and effective implementation, promotion of education and increasing farmers' awareness on effects of pesticide use were suggested to safeguard the farmers