458 research outputs found
Solubility prediction of weak electrolyte mixtures
International audienceThe solubility of materials is a thermodynamic variable that depends on their chemical composition and with temperature. Solubility is also affected by the pH, by the presence of additional species in the solution, and by the use of different solvents. On electrolyte, the calculation of solubility requires that the mean ionic activity coefficient be known along with a thermodynamic solubility product
Crystallization of zinc lactate in presence of malic acid
International audiencehe influence of malic acid, which acts as an impurity on the cooling crystallization of zinc lactate is investigated in this paper by monitoring the relative supersaturation and the number of crystals during crystallization. The presence of malic acid increases the solution solubility and makes the metastable zone wider; it also changes the habit of the crystal. The purity of the final products is shown to be influenced by the amount and size of seed crystals, cooling rate, seeding temperature and final temperature, but appears to depend mainly on the particle size and level of supersaturation. Residual supersaturation thresholds are observed that depend on the final temperature. A model is proposed to predict the steady-state supersaturation value from the final temperature at a given impurity concentration. This model is based on Kubota and Gibbs equations
A novel small peptide as an epidermal growth factor receptor targeting ligand for nanodelivery in vitro
Surface ligand controls silver ion release of nanosilver and its antibacterial activity against Escherichia coli
Understanding the mechanism of nanosilver-dependent antibacterial activity against microorganisms helps optimize the design and usage of the related nanomaterials. In this study, we prepared four kinds of 10 nm-sized silver nanoparticles (AgNPs) with dictated surface chemistry by capping different ligands, including citrate, mercaptopropionic acid, mercaptohexanoic acid, and mercaptopropionic sulfonic acid. Their surface-dependent chemistry and antibacterial activities were investigated. Owing to the weak bond to surface Ag, short carbon chain, and low silver ion attraction, citrate-coated AgNPs caused the highest silver ion release and the strongest antibacterial activity against Escherichia coli, when compared to the other tested AgNPs. The study on the underlying antibacterial mechanisms indicated that cellular membrane uptake of Ag, NAD+/NADH ratio increase, and intracellular reactive oxygen species (ROS) generation were significantly induced in both AgNP and silver ion exposure groups. The released silver ions from AgNPs inside cells through a Trojan-horse-type mechanism were suggested to interact with respiratory chain proteins on the membrane, interrupt intracellular O2 reduction, and induce ROS production. The further oxidative damages of lipid peroxidation and membrane breakdown caused the lethal effect on E. coli. Altogether, this study demonstrated that AgNPs exerted antibacterial activity through the release of silver ions and the subsequent induction of intracellular ROS generation by interacting with the cell membrane. The findings are helpful in guiding the controllable synthesis through the regulation of surface coating for medical care purpose
Diethyl [hydrÂoxy(phenÂyl)methÂyl]phosphoÂnate
MolÂecules of the title compound, C11H17O4P, are linked into chiral helical chains along the crystallographic b axis via OâHâŻO hydrogen bonds between the hydrÂoxy group and an O atom of the phosphoÂnate group. One ethyl group is disordered over two positions; the site occupancy factors are ca 0.7 and 0.3
Effect of combined function of temperature and water activity on the growth of Vibrio harveyi
Magnolin Protects against Contrast-Induced Nephropathy in Rats via Antioxidation and Antiapoptosis
BACKGROUND: Magnolin is the major active ingredient of the herb Magnolia fargesii which has anti-inflammatory and antioxidative effects. Oxidative stress and apoptosis are involved in the pathogenesis of contrast-induced nephropathy (CIN). We hypothesize that Magnolin could protect against CIN through antioxidative and antiapoptotic properties. METHODS: To test whether Magnolin could attenuate CIN, oxidative stress and apoptosis, in vivo and in vitro, we utilized a rat model of ioversol-induced CIN and a cell model of oxidative stress in which HK2 cells were treated with H2O2. Rats were assigned to 4 groups (n = 6 per group): control group, ioversol group (ioversol-induced CIN), vehicle group (CIN rats pretreated with vehicle), and Magnolin group (CIN rats pretreated with 1âmg/kg Magnolin). RESULTS: The results showed that magnolin ameliorated the renal tubular necrosis, apoptosis, and the deterioration of renal function (P < 0.05). Furthermore, Magnolin reduced the renal oxidative stress, suppressed caspase-3 activity, and increased Bcl-2 expression in vivo and in vitro. CONCLUSION: Magnolin might protect CIN in rats through antioxidation and antiapoptosis
Shape complexity and fractality of fracture surfaces of swelled isotactic polypropylene with supercritical carbon dioxide
We have investigated the fractal characteristics and shape complexity of the
fracture surfaces of swelled isotactic polypropylene Y1600 in supercritical
carbon dioxide fluid through the consideration of the statistics of the islands
in binary SEM images. The distributions of area , perimeter , and shape
complexity follow power laws , , and , with the scaling ranges spanning
over two decades. The perimeter and shape complexity scale respectively as
and in two scaling regions delimited by . The fractal dimension and shape complexity increase when the temperature
decreases. In addition, the relationships among different power-law scaling
exponents , , , , and have been derived analytically,
assuming that , , and follow power-law distributions.Comment: RevTex, 6 pages including 7 eps figure
Flexible Coherent Optical Access: Architectures, Algorithms, and Demonstrations
To cope with the explosive bandwidth demand, significant progress has been
made in the ITU-T standardization sector to define a higher-speed passive
optical network (PON) with a 50Gb/s line rate. Recently, 50G PON becomes mature
gradually, which means it is time to discuss beyond 50G PON. For ensuring an
acceptable optical power budget, beyond 50G PON will potentially use coherent
technologies, which can simultaneously promote the applications of flexible
multiple access such as time/frequency-domain multiple access (TFDMA). In this
paper, we will introduce the architectures, algorithms, and demonstrations for
TFDMA-based coherent PON. The system architectures based on an ultra-simple
coherent transceiver and specific signal spectra are designed to greatly reduce
the cost of ONUs. Meanwhile, fast and low-complexity digital signal processing
(DSP) algorithms are proposed for dealing with upstream and downstream signals.
Based on the architectures and algorithms, we experimentally demonstrate the
first real-time TFDMA-based coherent PON, which can support at most 256 end
users, and peak line rates of 100Gb/s and 200Gb/s in the upstream and
downstream scenarios, respectively. In conclusion, the proposed technologies
for the coherent PON make it more possible to be applied in the future beyond
50G PON.Comment: The paper has been submitted to the Journal of Lightwave Technolog
Effects of Malt Flour and Ascorbic Acid Additions on Bread Baking Quality
To study the effect of malt flour and ascorbic acid addition on the quality of bread bakingïŒ the sensory scoreïŒ texture and c-cell product image changes of the breads with malt flour and ascorbic acid addition were studied by using 29 representative samples from two major wheat producing provinces of henan and shandong. The results showed thatïŒ the volumeïŒ the volume scoreïŒ the appearance score and the final comprehensive score of bread were significantly improved after the addition of malt flour and ascorbic acid. The bread crown became larger and the neck became more prominent; howeverïŒ the colorïŒ texture and texture structure of bread scores changes were not obvious. In the analysis of textureïŒ the hardness and toughness decreased significantlyïŒ the attenuation ratio did not change obviously. The slice areaïŒ slice circumferenceïŒ cell number and cell density of bread increased significantly in the analysis of c-cell results.The slice brightness and cell diameter of the slices decreased significantly. There is a correlation between the instrument evaluation index and some parameters in the bread sensory evaluation
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