25 research outputs found
A New Iterative Scheme of Modified Mann Iteration in Banach Space
We introduce the modified iterations of Mann's type for nonexpansive mappings and asymptotically nonexpansive mappings to have the strong convergence in a uniformly convex Banach space. We study approximation of common fixed point of asymptotically nonexpansive mappings in Banach space by using a new iterative scheme. Applications to the accretive operators are also included
Decoupling Greenhouse Gas Emissions from Crop Production: A Case Study in the Heilongjiang Land Reclamation Area, China
Modern agriculture contributes significantly to greenhouse gas emissions in several ways. From the perspective of sustainability assessment, it is not enough to evaluate mitigation measures that rely only on emissions reductions. In this article, we use the method of decoupling analysis to construct a decoupling index based on carbon footprint and crop yield and evaluate the relationship between crop production and greenhouse gas emissions using the most modern grain production base in China as a case study. The results indicate that a weak but variable decoupling trend occurred from 2001 to 2015 and that each branch achieved on average a weak decoupling across the study period. In addition, rice production constituted 80% of the regional carbon footprint in a crop’s life cycle. The results of our analysis of rice production show that weak decoupling was the most common outcome but was not consistent because a weak coupling occurred in 2015. Each branch on average achieved a weak decoupling except for the SH branch. Our research indicates that high agricultural material inputs with low utilization efficiency contributed to the poor relationship between crop production and greenhouse gas emissions in the study area. Fertilizer, especially N fertilizer, was an important contributor to the total greenhouse gas emissions of crop production. As a supplement to carbon footprint assessment, this decoupling analysis helps local decision-makers diagnose the level of green growth, identify key options to mitigate greenhouse gas emissions from agriculture, and adopt more targeted interventions towards sustainable agriculture
Sodium dodecyl sulfate/β-cyclodextrin vesicles embedded in chitosan gel for insulin delivery with pH-selective release
In an answer to the challenge of enzymatic instability and low oral bioavailability of proteins/peptides, a new type of drug-delivery vesicle has been developed. The preparation, based on sodium dodecyl sulfate (SDS) and β-cyclodextrin (β-CD) embedded in chitosan gel, was used to successfully deliver the model drug-insulin. The self-assembled SDS/β-CD vesicles were prepared and characterized by particle size, zeta potential, appearance, microscopic morphology and entrapment efficiency. In addition, both the interaction of insulin with vesicles and the stability of insulin loaded in vesicles in the presence of pepsin were investigated. The vesicles were crosslinked into thermo-sensitive chitosan/β-glycerol phosphate solution for an in-situ gel to enhance the dilution stability. The in vitro release characteristics of insulin from gels in media at different pH values were investigated. The insulin loaded vesicles–chitosan hydrogel (IVG) improved the dilution stability of the vesicles and provided pH-selective sustained release compared with insulin solution–chitosan hydrogel (ISG). In vitro, IVG exhibited slow release in acidic solution and relatively quick release in neutral solutions to provide drug efficacy. In simulated digestive fluid, IVG showed better sustained release and insulin protection properties compared with ISG. Thus IVG might improve the stability of insulin during its transport in vivo and contribute to the bioavailability and therapeutic effect of insulin
Thermophysical and mechanical properties of cubic, tetragonal and monoclinic ZrO2
Yttrium-stabilized zirconia (YSZ) materials are routinely used as thermal barrier coatings (TBCs). The phase composition and microstructure of YSZ materials significantly influence their properties. In this study, ZrO2 ceramics composed respectively of monoclinic ZrO2 (m-ZrO2), tetragonal YSZ (t-YSZ) and cubic YSZ (c-YSZ) phases were sintered. The effect mechanism of phase composition and microstructure on thermophysical and mechanical properties were investigated by experiment together and numerical calculation. The result indicates that YSZ materials with c-YSZ phase are more suitable as TBC materials in terms of heat insulation, thermal expansion match with the metal substrate, and strain tolerance. The YSZ ceramic with c-YSZ phase also exhibits lower thermal conductivity than those composed of the t-YSZ and m-ZrO2 phases due to its greater lattice distortion, number of oxygen vacancies, and lower sound velocity as a result of greater Y2O3 doping. Bond lengths and cohesive energy calculations based on first principles reveal that the reason that the Y2O3 doping causes the CTE values of ZrO2 to increase is due to the bonding between ions becoming weaker, and the c-YSZ phase exhibits the highest CTE value. First-principles calculations also indicate that the c-YSZ phase exhibits a lower elastic modulus and better malleability and plasticity than m-ZrO2 and t-YSZ phases. However, the t-YSZ phase has better fracture toughness due to toughening under stress and finer grains
Identification of beagle food taking patterns and protocol for food effects evaluation on bioavailability
Abstract Food is a known primary role to the exposure of the drugs orally administered. Since each animal may have unique food taking pattern and it is difficult to manipulate the food taking to animals, there lacks rationalized protocol for the food effects in pre-clinic study. The objective of this study was to identify the beagle food taking patterns and demonstrate their effects on bioavailability in valsartan. Herein, four types of food taking patterns of beagle were identified via inter-day and intra-day analysis, and named as Persisting, Pulsing, Postponing, Pushing (“4P Modes”), respectively, which were also validated by principal component analysis (PCA). Interestingly, food intake resulted in a reduced area under the concentration-time curve (AUC0–12h), maximum concentration (Cmax) and absorption rate, whilst the reduction varied in “4P Modes” of food taking. General considerations in the design of experiment for food effect to the bioavailability in beagles have been established as: to recognize the food taking patterns in each animal, to confirm the inter-day stability of the food taking behaviors, to trace the food taking patterns in parallel with plasma sampling. In conclusion, the right animals with proper food taking patterns should be assessed and selected for pre-clinic bioavailability evaluations
Drug nanoclusters formed in confined nano-cages of CD-MOF: dramatic enhancement of solubility and bioavailability of azilsartan
Tremendous efforts have been devoted to the enhancement of drug solubility using nanotechnologies, but few of them are capable to produce drug particles with sizes less than a few nanometers. This challenge has been addressed here by using biocompatible versatile γ-cyclodextrin (γ-CD) metal-organic framework (CD-MOF) large molecular cages in which azilsartan (AZL) was successfully confined producing clusters in the nanometer range. This strategy allowed to improve the bioavailability of AZL in Sprague–Dawley rats by 9.7-fold after loading into CD-MOF. The apparent solubility of AZL/CD-MOF was enhanced by 340-fold when compared to the pure drug. Based on molecular modeling, a dual molecular mechanism of nanoclusterization and complexation of AZL inside the CD-MOF cages was proposed, which was confirmed by small angle X-ray scattering (SAXS) and synchrotron radiation-Fourier transform infrared spectroscopy (SR-FTIR) techniques. In a typical cage-like unit of CD-MOF, three molecules of AZL were included by the γ-CD pairs, whilst other three AZL molecules formed a nanocluster inside the 1.7 nm sized cavity surrounded by six γ-CDs. This research demonstrates a dual molecular mechanism of complexation and nanoclusterization in CD-MOF leading to significant improvement in the bioavailability of insoluble drugs. KEY WORDS: γ-Cyclodextrin metal-organic framework, Nanoclusterization, Azilsartan, Mechanism, Solubility, Bioavailability, Molecular modelin
A short-read multiplex sequencing method for reliable, cost-effective and high-throughput genotyping in large-scale studies
Accurate genotyping is important for genetic testing. Sanger sequencing-based typing is the gold standard for genotyping, but it has been underused, due to its high cost and low throughput. In contrast, short-read sequencing provides inexpensive and high-throughput sequencing, holding great promise for reaching the goal of cost-effective and high-throughput genotyping. However, the short-read length and the paucity of appropriate genotyping methods, pose a major challenge. Here, we present RCHSBTreliable, cost-effective and high-throughput sequence based typing pipelinewhich takes short sequence reads as input, but uses a unique variant calling, haploid sequence assembling algorithm, can accurately genotype with greater effective length per amplicon than even Sanger sequencing reads. The RCHSBT method was tested for the human MHC loci HLA-A, HLA-B, HLA-C, HLA-DQB1, and HLA-DRB1, upon 96 samples using Illumina PE 150 reads. Amplicons as long as 950bp were readily genotyped, achieving 100% typing concordance between RCHSBT-called genotypes and genotypes previously called by Sanger sequence. Genotyping throughput was increased over 10 times, and cost was reduced over five times, for RCHSBT as compared with Sanger sequence genotyping. We thus demonstrate RCHSBT to be a genotyping method comparable to Sanger sequencing-based typing in quality, while being more cost-effective, and higher throughput. (C) 2013 Wiley Periodicals, Inc
A “Ship-in-a-Bottle” strategy to create folic acid nanoclusters inside the nanocages of γ-cyclodextrin metal-organic frameworks
International audienc