Sargassum swartzii extracts ameliorate memory functions by neurochemical modulation in a rat model

Food Science and Biotechnology - Recently, considerable attention has been paid to drug exploration from natural sources for treating memory loss, a major manifestation of various neurodegenerative...     

Selenium (Se) improves drought tolerance in crop plants – a myth or fact?

Climate change has emerged as one of the most complex challenges of the 21st century and has become an area of interest in the past few decades. Many countries of the world have become extremely vulnerable to the impacts of climate change. The scarcity of water is a serious concern for food security of these countries and climate change has aggravated the risks of extreme events like drought. Oxidative stress, caused by a variety of active oxygen species formed under drought stress, damages many cellular constituents, such as carbohydrates, lipids, nucleic acids and proteins, which ultimately reduces plant growth, respiration and photosynthesis. Se has become an element of interest to many biologists owing to its physiological and toxicological importance. It plays a beneficial role in plants by enhancing growth, reducing damage caused by oxidative stress, enhancing chlorophyll content under light stress, stimulating senesce to produce antioxidants and improving plant tolerance to drought stress by regulating water status. Researchers have adopted different strategies to evaluate the role of selenium in plants under drought stress. Some of the relevant work available regarding the role of Se in alleviating adverse effect of drought stress is discussed in this paper. © 2015 Society of Chemical Industry     

Phase, microstructure and dielectric properties of 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 ceramics prepared by sol-gel technique

0.94Bi_0.5Na_0.5TiO₃-0.06BaTiO₃ ceramics were fabricated by sol-gel technique. The XRD results revealed the formation of a single phase perovskite structured Bi_0.5Na_0.5TiO₃-BaTiO₃ at 600 °C. The SEM images showed dense microstructure and the optimum density of the ceramics sintered at 1100 °C was 5.2 g/cm³. The saturation polarization (P _s ) was found to be increased with increasing temperature while the remnant polarization (P _r ) was found to be increased gradually and then decreased abruptly near 85 °C, which could be attributed to the phase transformation. The coercive electric field (E _c ) was found to be decreased gradually with increasing temperature. The maximum value of dielectric constant (? _r ) at room temperature was 800 and dielectric loss at 1 MHz was 0.07.     

Breakthrough studies with mono- and binary-metal ion systems comprising of Fe(II) and As(III) using community prepared wooden charcoal packed columns

Groundwater of Assam (India) contains excessive amounts of As(III) and Fe(II). The rural and semi-urban population of Assam uses indigenous household iron filters fabricated using community prepared wooden charcoal (CPWC) to reduce Fe(II) concentration, however no efforts are made to reduce As(III) concentrations before use. The present work is directed toward assessing the potential of CPWC for metal removal from mono- and binary-metal ion systems comprising of Fe(II) and As(III) through continuous mode column studies. A decrease in breakthrough throughput volumes (V_B) from mono- and binary-metal ion systems is observed with increase in flow rates and decrease in bed depths. The order of breakthrough of metal ions observed as As(III) followed by Fe(II) from binary-metal ion system and hence the V_B for As(III) is termed as critical V_B as Fe(II) is yet to breakthrough through the beds. An early breakthrough for Fe(II) and As(III) from binary-metal ion system compared to respective mono-metal ion systems is observed for all the cases of flow rates and bed depths. It indicates impact on the uptake of a selected metal ion [either Fe(II) or As(III)] by the presence of the other metal ion [either As(III) or Fe(II)] present in the binary-metal ion system. The minimum and maximum errors involved between the predicted and experimental BDST curves for As(III) uptake till critical V_B from the binary-metal ion system varied between 1.0% and 24.8%.     

Effects of QD concentrations and thermal annealing on the performance of self-assembly QD-OLEDs

We have fabricated and investigated the effect of CdSe/ZnS quantum dot (QD) concentrations on the performance of self-assembly hybrid inorganic/organic light emitting diodes (QD-OLEDs). The uniform distribution of QDs with controllable density was achieved using the conventional spin-coating method. There was a QD threshold concentration for the emission of QDs in QD-OLED. Below that threshold concentration we did not observe the QD emission from the QD-OLED. The best performance of QD-OLED was found for the QD concentration of -9 x 10(11) cm(-2). The QD electroluminescence intensity was increased about three times after the annealing of QD-OLED at 80 degrees C for about 20 minutes in nitrogen atmosphere. The QD electroluminescence peak energy was remain same before and after the annealing of QD-OLED. The maximum external quantum efficiency was around 2.1%. The effect of process parameters and the QD emission mechanism are discussed.     

A note on water quality associated with slaughter premises in Bangladesh

Water quality used for washing carcasses and abattoir premises was assessed at two sites in southeast Bangladesh. In addition, the effect of discharging untreated washings from slaughter premises on water purity in the receiving waterways was assessed from pH, dissolved oxygen and electrical conductivity measurements. Premises effluents did not have a significant effect on the physico-chemical properties of the water in the receiving canals, as determined from the difference between the 4 m upstream and 4 m downstream samples, relative to the entry point of the effluent. When a water shortage occurred at one of the premises, water was sourced for washing the carcasses and premises from a canal that was also used for conveying municipal effluent. The discharge water from the premises at this time had a pH, dissolved oxygen content and conductivity of 7.93, 1.84 mg/L and 6.06 mS/cm respectively, and this would be a threat to survival of freshwater animal life.     

EXTRACTION OF BTX FROM NAPHTHA REFORMATE USING A MIXER-SETTLER CASCADE

A study was made of the performance of a 10-stage laboratory mixer-settler cascade for the extraction of benzene-toluene-xylene (BTX) from a synthetic reformate utilizing sulfolane as solvent. Murphree stage efficiency decreased with stage number but 99% extraction was achievable within 4 stages. The effects of temperature, phase ratio, and agitator speed were investigated. The efficiency increased with agitator speed but >1050 rpm resulted in secondary haze formation. An optimum temperature of 30°C was selected from the phase equilibria; the optimum solvent: feed ratio was 3:1.     

Dielectric,electrical, and rheological characterization of graphene‐filled polystyrene nanocomposites

A series of nanographene filled polystyrene (GPS) nanocomposites was prepared by in situ polymerization of styrene in the laboratory. The concentration of graphene was changed in the step of 0.25 wt% and a total of eight composites (including control) were prepared to obtain a threshold concentration of graphene. These composites, prepared by in situ polymerization followed by compression moulding, were characterized for their structural (using XRD), morphological (SEM), thermal (DSC, TGA, DTGA), dielectric behavior (ɛ', ɛ''') and DC conductivity. It was observed that the thermal stability as well as electrical and rheological properties of graphene‐polystyrene nanocomposites significantly improved due to the homogeneous dispersion, intercalation and exfoliation of the graphene layers in the Polystyrene matrix. It was also observed that at room temperature dielectric constant (ε′) decreased with increasing concentration of graphene and reached a minimum at a certain filler concentration of 0.25 wt% (PSG025) when frequency is kept constant. Rheological study showed an improvement in the storage modulus (G′) with incorporation of graphene as nanofiller. Loss modulus (G′) and complex viscosity (η*) also increased with increasing graphene weight percentage. Relaxation time also increased at high graphene loading because of the pseudo‐solid like behavior of polymer melt. POLYM. COMPOS., 34:2082–2093, 2013. © 2013 Society of Plastics Engineers     

Potential release pathways, environmental fate, and ecological risks of carbon nanotubes

Carbon nanotubes (CNTs) are currently incorporated into various consumer products, and numerous new applications and products containing CNTs are expected in the future. The potential for negative effects caused by CNT release into the environment is a prominent concern and numerous research projects have investigated possible environmental release pathways, fate, and toxicity. However, this expanding body of literature has not yet been systematically reviewed. Our objective is to critically review this literature to identify emerging trends as well as persistent knowledge gaps on these topics. Specifically, we examine the release of CNTs from polymeric products, removal in wastewater treatment systems, transport through surface and subsurface media, aggregation behaviors, interactions with soil and sediment particles, potential transformations and degradation, and their potential ecotoxicity in soil, sediment, and aquatic ecosystems. One major limitation in the current literature is quantifying CNT masses in relevant media (polymers, tissues, soils, and sediments). Important new directions include developing mechanistic models for CNT release from composites and understanding CNT transport in more complex and environmentally realistic systems such as heteroaggregation with natural colloids and transport of nanoparticles in a range of soils.