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关键词： Biomaterial   Biomass   Nanocellulose   Physicochemical properties   Piezoelectric effect  

摘要： The present work focuses on the development of cellulose nanofibrils (CNF) film that derived from sustainable biomass resources, which potentially to work as bio-based conductive membranes that assembled into supercapacitors. The chemically purified cellulose was isolated from different parts of coconut (coconut shell and its husk) and further subjected to 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation for CNF preparation. Physicochemical properties of prepared CNFs were studied in terms of chemical characteristics & crystallinity, surface functionalities, surface morphology, and thermal properties. Both coconut shell derived CNF and coconut husk-derived CNF fulfilled with nanocellulose's characteristics with fibres width ranged of 70-120 nm and 150-330 nm, respectively. CNF films were further prepared by solvent casting method to measure the modulus elasticity, piezoelectric and dielectric properties of the films. Mechanical study indicated that coconut shell-derived CNF film showed a higher value of elastic modulus than the coconut husk-derived CNF film, which was 8.39 GPa and 5.36 GPa, respectively. The effectiveness of electrical aspects for CNF films are well correlated with the crystallinity and thermal properties, associated with it's composition of different coconut's part. (c) 2021 Elsevier B.V. All rights reserved.

关键词： Seasonal variation   Physicochemical parameter   Water quality   Factor analysis   Cluster analysis   Turag River  

摘要： To assess the magnitude of water quality decline in the Turag River of Bangladesh,this study examined the seasonal variation of physi-cochemical parameters of water,identified potential pollution sources,and clustered the monitoring months with similar *** samples were collected in four distinct seasons to evaluate temperature,pH,dissolved oxygen(DO)concentration,five-day biochemical oxygen demand(BOD 5),chemical oxygen demand(COD),electrical conductivity(EC),chloride ion(Cl^(-))concentration,total alkalinity(TA),turbidity,total dissolved solids(TDS)concentration,total suspended solids(TSS)concentration,and total hardness(TH)using standard *** analytical results revealed that 40%of water quality indices were within the permissible limits suggested by different agencies,with the exception of EC,Cl^(-)concentration,TA,turbidity,DO concentration,BOD 5,and COD in all *** analyses indicated that 52%of the contrasts were significantly different at a 95%confidence *** factor analysis presented the best fit among the parameters,with four factors explaining 94.29%of the total ***,BOD 5,COD,EC,turbidity,DO,and Cl?were mainly responsible for pollution loading and were caused by the significant amount of industrial discharge and toxicological *** cluster analysis showed the seasonal change in surface water quality,which is usually an indicator of pollution from rainfall or other ***,the values of different physico-chemical properties varied with seasons,and the highest values of pollutants were recorded in the *** the change in seasonal tem-perature and increase in rainfall,the seasonal Turag River water followed a self-refining trend as follows:rainy season>pre-winter>summer>winter.

关键词： 物理化学   理想气体   可逆过程   体积功  

摘要： 热和功都不是状态函数,它们的值与系统经历的具体过程相关。在物理化学课程中理想气体系统体积功的计算是物理化学教学的重点之一,亦是难点之一。理想气体沿pT=常数的途径可逆膨胀或压缩过程是一类特殊的过程,此过程中可逆体积功的计算较难。本文采用五种不同的方法对此过程中的体积功进行了计算。介绍了这类问题的解题思路和技巧。

关键词： Mangiferin   Chitosan composite   Sol-gel   Hybrid material   Bone regeneration   Cytotoxicity  

摘要： Development of hybrid materials with molecular structure of organic-inorganic co-network is a promising method to enhance the stability and mechanical properties of biopolymers. Chitosan-silica hybrid nanocomposite scaffolds loaded with mangiferin, a plant-derived active compound possessing several bioactivities, were fabricated using the sol-gel synthesis and the freeze-drying processes. Investigation on the physicochemical and mechanical properties of the fabricated scaffolds showed that their properties can be improved and tailored by the formation of 3-dimensional crosslinked network and the addition of ZnO nanoparticles. The scaffolds possessed porosity, fluid uptake, morphology, thermal properties and mechanical strength suitable for bone tissue engineering application. Investigation on the biomineralization and cell viability indicated that the inclusion of bioactive mangiferin further promote potential use of the hybrid nanocomposite scaffolds in guided bone regeneration application.

关键词： Dyes removal   Anion exchanger   Sodium dodecyl sulfate   Triton X-100   Kinetic and equilibrium studies   Textile wastewaters  

摘要： Batch and column methods as well as spectroscopic, surface tension and conductivity measurements were used to establish interactions between the C.I. Acid Green 16 dye (AG16) and the strongly basic anion exchange resin Lewatit S 6368 A (6368A) of polystyrene matrix in the presence of selected auxiliaries. Equilibrium and kinetic studies were carried out in a wide range of experimental conditions such as dye and auxiliaries concentrations, temperature or phase contact time. Next, the adsorption parameters were calculated using the Freundlich, Langmuir, Temkin and Dubinin-Radushkevich isotherm models as well as the pseudo-first order, pseudo-second order and intraparticle diffusion models. It was found that the sorption capacities of the resin increase from 625.2 to 811.6 mg/g with the temperature increase from 293 to 333 K. AG16 uptake decrease with the anionic (SDS) and nonionic (TX100) surfactant addition. There is also a strong sorption of only SDS on 6368A as well as AG16-SDS complexes/aggregates which are less conducting after sorption than before. After sorption at higher temperatures there are also more (non-associated) AG16 ions in the TX100 solution than in the SDS one which has an important effect on sorption and desorption processes. Resin regeneration can be procced using 1M HCl or 1 M NaCl in 50%v/v MeOH with the 99.07-92.6% and 88.75-80.0% yield, respectively. (C) 2021 Elsevier B.V. All rights reserved.

关键词： Theranostic system   ZIF-8   Polyacrylic acid   Mn3O4 nanoparticles   pH-sensitive nanocarrier  

摘要： An integrated nanocomposite system comprising of manganese oxide (Mn3O4) nanoparticles, functioning as a tumor diagnostic agent, in conjunction with polyacrylic acid (PAA) and ZIF-8, as pH-sensitive drug delivery agents, and methotrexate (MTX), operating as a tumor biomarker and a therapeutic agent (dual mechanism of action), is applied for both diagnostic intentions and controlled delivery of the drug. Physicochemical characteristics of the constructed system, Mn3O4@PAA@ZIF-8/MTX, are investigated by several methods, including X-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, and electrochemical techniques. The in-vitro magnetic resonance imaging measurements was performed to show the efficiency of Mn3O4@PAA@ZIF-8 nanocomposite as a contrast agent where a relaxivity (r(1)) of 3.3 mM(-1) s(-1) is found. The loading ratio was found as 161 % which is four times larger than the value obtained for Mn3O4@PAA system in the same conditions, indicating high capability of the system for MTX delivery. The application of the nanocomposite as a dual pH-sensitive nanocarrier for MTX is studied through in-vitro drug release experiments at pHs of 5.4, 6.8 and 7.4. Interestingly, the results show that a large amount of loaded MTX drug (53 %) is released from the system during incubation and dialysis at pH 5.4, compared with that (20 % and 15 %), respectively, released at pHs 6.8 and 7.4 at the same conditions. The affinity of Mn3O4@PAA@ZIF-8/ MTX nanocomposite for capturing of BT-474 and MCF-7 cancer cells was evaluated via impedance spectroscopy measurements. The results show that GC-Mn3O4@PAA@ZIF-8/MTX electrode captures the BT-474 and MCF-7 cancer cells, respectively, by factors of similar to 2 and 196 compared with L929 normal cells. This affinity also shows the high selectivity of the system for MCF-7 cancer cells compared with BT-474.

关键词： Whole corn slurry   Microfluidizer   Nutrition   Stability   Particle size  

摘要： A novel "industry-scale microfluidizer system" (ISMS) was used to prepare whole corn slurry (WCS). The impact of processing pressure (0-120 MPa) on the properties of WCS was examined. ISMS preserved the soluble solid content, stabilized the native pH (similar to 7.2), and retained the desirable yellow color of WCS. Moreover, it did not adversely impact the concentration of major nutrients, such as starch (similar to 50 g/100g), protein (similar to 13 g/100g), fat (similar to 8 g/100g) and dietary fiber (similar to 17 g/100g). ISMS also increased the polyphenol content and improved the in vitro antioxidant activity of WCS. Increasing the pressure led to an improvement in the physical stability of WCS, which was linked to the reduction in particle size, increase in viscosity, improved dispersion of the particulate matter and formed network with decreased dimensions. These results suggest that ISMS can be a new processing tool to create whole corn beverages with improved nutritional value, enhanced shelf life, and better functional performance.

关键词： Physicochemical attributes   Potato   Semi-underground storage   Sensory attributes  

摘要： This study assessed the feasibility of providing a regular supply of locally produced potatoes during landlocked winter months in Ladakh region. Potato tubers were stored (January-May) in semi-underground stores where conditions were between 0.2-13.6 degrees C and 87-96% relative humidity. Periodical sample analysis was carried out on sensory attributes and the physicochemical attributes firmness, sprouting, pulp temperature, total soluble solutes, sugar level, vitamin B6, dry matter, weight loss and CIPC residue level, to evaluate the quality of the stored potatoes. Pearson's correlation analysis measured the relationship between various physicochemical attributes that helped improve understanding of potato variability. CIPC residue concentration was within the recommended limit of 30 mg/kg tuber in peeled and unpeeled tubers ranging from 0.02 to 0.12 mg/kg and 0.04 to 3.90 mg/kg, respectively. Tubers stored during extreme winter conditions showed the highest level of total sugar 927 +/- 8.54 mg/100 g after 5 months of storage. Vitamin B6 was 0.276 mg/100 g in CIPC treated potato and 0.190 mg/100 g in non-treated potato which is approximately 15% of recommended daily vitamin B6 intake. Based on the results of this study, potatoes stored in zero energy-based semi-underground stores were in good quality after a period of 5 months and suitable for consumption.

关键词： Soil quality   Soil fertility gradients   Agronomic use efficiency   Physical soil quality indicators  

摘要： Conservation Agriculture (CA) and Integrated Soil Fertility Management (ISFM) have been promoted in Sub Saharan Africa as a means to improve soil quality. A four season research (March, 2017 to March, 2019) was conducted to evaluate CA-based treatment, no tillage with residue retention (NTR), ISFM-based treatment, conventional tillage with use of manure (CTM), a combination of CA + ISFM, no tillage with residue retention and use of manure (NTRM) and a control, (C) on soil quality attributes. In the two locations (sub-humid and semi-arid) the effect of soil fertility gradients (high and low) were considered. Trials were set out using a one farm one replicate randomized design. In either high or low fertility fields, soil chemical and physical properties were significantly different between the control and NTR, CTM and NTRM with no significant differences between NTR, CTM and NTRM. SOC was higher under NTR and NTRM practices, which consequently had higher hydraulic conductivity, air permeability, mean weight diameter and available phosphorus. For all the treatments and in both locations, the low fertility fields had significantly lower agronomic use efficiency (AUE) compared to the high fertility fields. In both soil types, plant available water capacity and relative water capacity values were below the recommended thresholds indicating low soil water uptake, suboptimal microbial activity and consequently low nutrient uptake which explains the observed low AUE.

关键词： Human milk   Human milk macronutrients   Physico-chemical properties   Human milk ingredients   Milk processing   Human milk banking  

摘要： Background: Human milk is recommended as the optimal source of nutrition for babies up to six months of age, as it provides individualized, specific and abundant nutritional compounds, as well as immunological protection. Currently, there is wide interest in studying human milk because of this key role, as well as identification of biologically active compounds. In addition, human milk banks play an important role in supplying donor human milk to infants, especially premature infants, in hospitals, which involves processing and storage of such milk. Scope and approach: This review summarises recent studies on macronutrients in human milk, including their structure, levels, influencing factors, and contributions to the health benefits of infants. Physico-chemical properties of human milk are also reviewed, including pH, colour, stability of casein micelles, size and zetapotential of fat globules, heat stability, freeze-thaw effect, dehydration and phase separation, and the impact of preservation processes on these. Key findings and conclusions: The levels of human milk macronutrients and factors that influence these, such as lactation and gestational age, are ongoing research topics. Studies on physicochemical properties of some human milk components, such as caseins, are comparatively few, as research has mainly focused on bioactive peptides, milk fat globule membrane and human milk oligosaccharides. Processing and preservation are applied to human milk and the effects of these methods on the retention of human milk nutrients for use in human milk banks and hospitals must be considered. Some physico-chemical properties, such as milk pH, colour, and physical stability, may be possible indicators of milk quality.