Borosilicate glasses modified with organic ligands: a new selective approach for the removal of uranyl ion

Barium borosilicate glass was found to have high uptake capacity for many cations. To improve its selectivity, surface modification was carried out. In order to make the glass selective towards uranyl ion, organic ligands like tri-n-octylphosphine oxide (TOPO) and 8-hydroxy quinoline (Oxine) were used. It was observed that the surface modification resulted in the change in uptake property of the glass. The uptake process was faster and within 5 h, 90% of the uranyl ion could be taken up from a 0.01 mM solution. With use of the modified barium borosilicate glass and EDTA as masking agent, uranyl ion could be selectively removed from mixtures of cations.     

Small-angle neutron scattering investigations on sintering behavior of combustion synthesized La0.8Sr0.2CrO3

Pore morphology of La0.8Sr0.2CrO3 (LSC) powder compacts, sintered between 1200 degrees C and 1450 degrees C for a fixed time, has been characterized by small-angle neutron scattering (SANS) in the scattering wave vector 'q' range, 0.003-0.17 nm(-1) of a double crystal based instrument. Scattering profile of green compact exhibits fractal scaling at two regions of 'q' with magnitudes of fractal dimensionality 1.8 and 2.36. Scattering profiles of sintered pellets have been modeled assuming a random distribution of near spherical pores in the solid matrix. Estimated pore size distributions of sintered pellets indicate decrease in pore volume has taken place by progressive elimination of smallest pores and growth of relatively larger pores with increasing sintering temperature. SANS results are supplemented by light scattering measurement and TEM image of powder and SEM image of the fracture surface of sintered pellet.     

Luminescence properties of SnO2 nanoparticles dispersed in Eu3+ doped SiO2 matrix

SnO2 nanoparticles dispersed in Eu3+ doped silica (SnO2-SiO2:Eu3+) were prepared at a low temperature (185 degrees C) in ethylene glycol medium. Transmission electron microscopy studies on as-prepared samples have established that SnO2 nanoparticles having size of 4.6 nm are uniformly covered by the SiO2 matrix. Significant extent of exciton mediated energy transfer between SnO2 and Eu3+ ions in heat treated SnO2-SiO2:Eu3+ samples has been attributed to the diffusion of Eu3+ ions from the SiO2 matrix to the near vicinity of SnO2 nanoparticles and its incorporation in the SnO2 matrix. On the other hand, very weak energy transfer exists for SnO2:Eu3+ nanoparticles heated at different temperatures due to the phase segregation of Eu3+ ions from the matrix.     

M-PAM space?time trellis codes for ultra-wideband multiple-input multiple-output communications

Multiple-input multiple-output (MIMO) systems with space-time (ST) coding are desirable in ultra- wideband (UWB) communication systems to improve the error-rate performance of the UWB link. The authors have considered the design of optimal (in error-rate performance) M-ary pulse-amplitude modulated (M-PAM) ST trellis codes (STTC) for a pulse-based UWB MIMO communication system. Following the approach by Vucetic et al. for narrowband systems, the authors carry out a probability of error analysis to derive upper bounds on pairwise symbol error probability for a UWB communication system for slow fading and fast fading at both low and high signal-to-noise ratios (SNRs). The authors deduce the design criteria from the upper bounds. Based on these criteria, an optimal four-state binary-PAM STTC, for two transmit antennas, is designed by hand. Finally, simulation results of the optimal binary-PAM STTC in a UWB communication system confirm significant improvement in bit error-rate performance over previously proposed ST coding scheme for UWB, at higher transmit SNR.     

亚麻/粘胶混纺纱

亚麻是一种天然纤维 ,在中国种植了大约6 5万公顷 ,在印度、巴基斯坦、孟加拉等国也有大量栽培。基于亚麻的一些物理特性 ,例如强度和耐磨性 ,它早期的用途仅限于做包装及装饰织物。然而 ,最近关于亚麻纱线用途的研究表明 :不同细度及纤维混纺比的纱线可以用来生产新型的轻质服装、礼服、衬衫和床上用品。尽管由于亚麻纤维高的刚度会使这些织物手感粗糙 ,但是纤维的亲水特性开启了其在机织及针织服用纺织品领域新的发展。通过转杯纺、包缠纺和摩擦纺 ,可以将亚麻纤维纺成短纤纱。但是 ,在亚麻纱的机织和针织加工中要进一步解决其弹性低和短…     

Chemical composition, in vitro anti-yeast activity and fruit juice preservation potential of lemon grass oil

The anti-yeast activity of lemon grass oil was evaluated against several food spoiling yeasts (Saccharomyces cerevisiae, Zygosaccharomyces bailii, Aureobasidium pullulans, Candida diversa, Pichia fermentans, Pichia kluyveri, Pichia anomala and Hansenula polymorpha) through disc diffusion and microbroth dilution method. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) varied from 0.28 to 1.3 mg/ml and 0.56 to 4.5 mg/ml, respectively, where highest MIC (2.25 mg/ml) was shown by A. pullulans and lowest MIC (0.28 mg/ml) was shown by C. diversa and P. anomala. Kill time assay was conducted for selected three yeast strains where S. cerevisiae showed highest reduction (3 log cfu) in viability within 24 h exposure of lemon grass oil at MFC level. Further, the anti-yeast efficacy of lemon grass oil alone and in combination with thermal treatment was evaluated in real food system i.e. mixed fruit juices. Chemical composition analysis of lemon grass oil by gas chromatography–mass spectrometry (GC–MS) revealed that the dominant compounds were geranial (40.5%), neral (30.7%), geranyl acetate (5.1%), caryophyllene (2.5%). Present results established the superior performance of integrated (thermal–lemon grass oil) treatment over the individual exposure (lemon grass oil or thermal treatment alone) for fruit juice preservation.     

Preliminary evaluation of nutraceutical and therapeutic potential of raw Spondias pinnata K., an exotic fruit of India

The underutilized, edible green raw (whole) fruits of amra, Spondias pinnata K. (Anacardiaceae family) from the eastern region of India were investigated for their nutraceutical and therapeutic potential. A thorough nutritional characterization of this fruit demonstrated it as a source of energy (348 kcal/100 g DM), phenolic compounds, natural antioxidants and minerals. It is also a moderate source of ascorbic acid, malic acid, calcium, phosphorus and other nutrients. The phytochemical screening revealed 5.12 ± 0.32 mg 100 g^− 1 DM of alkaloids followed by saponins and tannins. All assays were carried out in three different solvent extracts of the fruit. Total phenolic, flavonoid and flavonol contents were obtained as 210 ± 1.89 mg GAE, 28.0 ± 0.91 mg CE and 9.97 ± 0.72 mg RE respectively in 100 mg mix solvent extract (MSE). Antioxidant activity of different extracts (as DPPH scavenging) ranged from 0.73 to 0.59 mg ml^− 1 as IC₅₀ value, ABTS with a trolox equivalent antioxidant concentration (TEAC) value as 0.68 to 0.83 and FRAP 5.97 to 7.93 mg TE 100 mg^− 1 extract. LC- MS/MS analysis revealed the presence of gallic acid, salicylic acid, chlorogenic acid, ellagic acid, p-coumaric acid, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, quercetin, catechin, myrecetin and rutin. The MSE showed the highest antimicrobial activity (against Listeria monocytogenes (MIC 1.8 mg ml^− 1)) and ??-amylase inhibition capacity (as IC₅₀: 29.3 mg ml^− 1 extract). GC/MS screening showed the presence of vitamin E, furfural, phytosterol, campesterol and fatty acids. Analysis of volatile flavor showed isopropyl myristinate as a major compound followed by the other monoterpenes and sesquiterpenes. The current study explains the nutritional as well as medicinal utility of the fruit which is a rich source of minerals and antioxidants such as phenols and flavonoids.     

Seed biopriming as a promising approach for stress tolerance and enhancement of crop productivity: a review

Chemicals are used extensively in agriculture to increase crop production to meet the nutritional needs of an expanding world population. However, their injudicious application adversely affects the soil's physical, chemical and biological properties, subsequently posing a substantial threat to human health and global food security. Beneficial microorganisms improve plant health and productivity with minimal impact on the environment; however, their efficacy greatly relies on the application technique. Biopriming is an advantageous technique that involves the treatment of seeds with beneficial biological agents. It exhibits immense potential in improving the physiological functioning of seeds, thereby playing a pivotal role in their uniform germination and vigor. Biopriming-mediated molecular and metabolic reprogramming imparts stress tolerance to plants, improves plant health, and enhances crop productivity. Furthermore, it is also associated with rehabilitating degraded land, and improving soil fertility, health and nutrient cycling. Although biopriming has vast applications in the agricultural system, its commercialization and utilization by farmers is still in its infancy. This review aims to critically analyze the recent studies based on biopriming-mediated stress mitigation by alteration in physiological, metabolic and molecular processes in plants. Additionally, considering the necessity of popularizing this technique, the major challenges and prospects linked to the commercialization and utilization of this technique in agricultural systems have also been discussed. © 2023 Society of Chemical Industry.     

Correlation of phase transition with the change in TL characteristics in CaSO4:Dy phosphor--effect of thermal treatment

The study is aimed at optimising the glow curve structure of CaSO4:Dy phosphor for dosimetric purpose and also to understand the observed changes owing to thermal treatment in the thermoluminescence (TL) sensitivity and glow curve structure. The reversible changes in the intensities of the lower temperature satellite peak and the main dosimetric glow peak with temperature of thermal treatment in the temperature range 400-700 degrees C indicates the interconversion of defect complexes responsible for the glow peaks in CaSO4:Dy. Phosphor samples subjected to thermal treatment in temperature range beyond 800 degrees C, showed irreversible changes in the intensities of the lower temperature and dosimetric peaks. The changes in TL characteristics of the phosphor for thermal treatments >800 degrees C are attributed to the partial phase transition in the phosphor as confirmed by the XRD and TG/DTA analysis of the phosphor.     

Synthesis and characterization of nanocrystalline mesoporous zirconia using supercritical drying

Synthesis of nano-crystalline zirconia aerogel was done by sol-gel technique and supercritical drying using n-propanol solvent at and above supercritical temperature (235-280 degrees C) and pressure (48-52 bar) of n-propanol. Zirconia xerogel samples have also been prepared by conventional thermal drying method to compare with the super critically dried samples. Crystalline phase, crystallite size, surface area, pore volume, and pore size distribution were determined for all the samples in detail to understand the effect of gel drying methods on these properties. Supercritical drying of zirconia gel was observed to give thermally stable, nano-crystalline, tetragonal zirconia aerogels having high specific surface area and porosity with narrow and uniform pore size distribution as compared to thermally dried zirconia. With supercritical drying, zirconia samples show the formation of only mesopores whereas in thermally dried samples, substantial amount of micropores are observed along with mesopores. The samples prepared using supercritical drying yield nano-crystalline zirconia with smaller crystallite size (4-6 nm) as compared to higher crystallite size (13-20 nm) observed with thermally dried zirconia.