In Situ Absorption in Rat Intestinal Tract of Solid Dispersion of Annonaceous Acetogenins

Isolated from Annona squamosa L, Annonaceous acetogenins (ACGs) exhibit a broad range of biological properties yet absorbed badly due to the low solubility. Solid dispersion in polyethylene glycol 4000 (PEG 4000) has been developed to increase the solubility and oral absorption of ACGs. The formulation of ACGS-solid dispersion was optimized by a simplex lattice experiment design and carried out by a solvent-fusion method. We studied the absorption property of ACGs in rat's intestine, which showed there was a good absorption and uptake percentages with solid dispersion. The study on uptake percentage in different regions of rat's intestine attested that the duodenum had the best permeability, followed by jejunum, ileum, and colon in order with no significant differences. So the paper drew the conclusion that solid dispersion could improve the solubility and oral absorption of annonaceous acetogenins

Comparison among Reconstruction Algorithms for Quantitative Analysis of 11

Objective. Kinetic modeling of dynamic 11C-acetate PET imaging provides quantitative information for myocardium assessment. The quality and quantitation of PET images are known to be dependent on PET reconstruction methods. This study aims to investigate the impacts of reconstruction algorithms on the quantitative analysis of dynamic 11C-acetate cardiac PET imaging. Methods. Suspected alcoholic cardiomyopathy patients (N=24) underwent 11C-acetate dynamic PET imaging after low dose CT scan. PET images were reconstructed using four algorithms: filtered backprojection (FBP), ordered subsets expectation maximization (OSEM), OSEM with time-of-flight (TOF), and OSEM with both time-of-flight and point-spread-function (TPSF). Standardized uptake values (SUVs) at different time points were compared among images reconstructed using the four algorithms. Time-activity curves (TACs) in myocardium and blood pools of ventricles were generated from the dynamic image series. Kinetic parameters K1 and k2 were derived using a 1-tissue-compartment model for kinetic modeling of cardiac flow from 11C-acetate PET images. Results. Significant image quality improvement was found in the images reconstructed using iterative OSEM-type algorithms (OSME, TOF, and TPSF) compared with FBP. However, no statistical differences in SUVs were observed among the four reconstruction methods at the selected time points. Kinetic parameters K1 and k2 also exhibited no statistical difference among the four reconstruction algorithms in terms of mean value and standard deviation. However, for the correlation analysis, OSEM reconstruction presented relatively higher residual in correlation with FBP reconstruction compared with TOF and TPSF reconstruction, and TOF and TPSF reconstruction were highly correlated with each other. Conclusion. All the tested reconstruction algorithms performed similarly for quantitative analysis of 11C-acetate cardiac PET imaging. TOF and TPSF yielded highly consistent kinetic parameter results with superior image quality compared with FBP. OSEM was relatively less reliable. Both TOF and TPSF were recommended for cardiac 11C-acetate kinetic analysis

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Effect of Fe on the Microstructure and Mechanical Properties of Fe/FeAl2O4 Cermet Prepared by Hot Press Sintering

The Fe/FeAl2O4 cermet was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method at 1400 °C. The raw materials for the powder particles were respectively 2 µm (Fe), 0.5 µm (Fe2O3), and 0.5 µm (Al2O3) in diameter, the sintering pressure was 30 MPa, and the holding time was 120 min. The effects of different Fe mass ratios on the microstructure and mechanical properties of Fe/FeAl2O4 cermet were studied. The results showed that a new ceramic phase FeAl2O4 could be formed by an in situ reaction during the hot press sintering. When the Fe mass ratio was increased, the microstructure and mechanical properties of the Fe/FeAl2O4 cermet showed a change law that initially became better and then became worse. The best microstructure and mechanical properties were obtained in the S2 sample, where the mass ratio of Fe-Fe2O3-Al2O3 was 6:1:2. In this Fe mass ratio, the relative density was about 94%, and the Vickers hardness and bending strength were 1.21 GPa and 210.0 MPa, respectively. The reaction mechanism of Fe in the preparation process was the in situ synthesis reaction of FeAl2O4 and the diffusion reaction of Fe to FeAl2O4 grains. The increase of the Fe mass ratio improved the wettability of Fe and FeAl2O4, which increased the diffusion rate of Fe to FeAl2O4 grains, which increased the influence on the structure of FeAl2O4

Molecular-weight-dependent redox cycling of humic substances of paddy soils over successive anoxic and oxic alternations

Humic substances (HSs) are critical to regulating methane cycling in temporary anoxic systems because their redox-active functional groups can sustainably shuttle electrons from microorganisms to oxygen (O-2) over successive anoxic and oxic alternations. Whether the relative amount of these redox-active functional groups involved in redox cycles is associated with the overall chemical structures of HS still remains poorly understood. In this study, variations in the reducing capacities (RCs) of HSs extracted from paddy soils were monitored over consecutive cycles of reduction by iron-reducing microorganisms and oxidation by O-2. Our results show that about 10-40% of the microbially reduced redox-active moieties within HS, which were reoxidised by O-2, cannot restore the same redox state as those before microbial reduction. The restoration extents of RCs of HSs after microbial reduction and O-2 reoxidation were greatly negatively correlated with average molecular weight (AMW). The microbially reduced HSs having large AMWs (>1,000 Da) were more kinetically difficult to restore by O-2 from a reduced state to an oxidised state than were those having small AMWs (<1,000 Da) possibly because the former, which underwent process of microbial reduction and O-2 reoxidation, were more easily sheltered by other parts of HS structures than were the latter. Nevertheless, the unsheltered redox-active groups that accounted for about 50-85% in HSs can be fully reversible and sustainable to switch between a reduced state and an oxidised state over successive redox cycles. Our results can help to understand the redox dynamics of HSs in biogeochemical cycles in environments

pXST, a novel vector for TA cloning and blunt-end cloning

Abstract Background With the rapid development of sequencing technologies, increasing amount of genomic information has been accumulated. To clone genes for further functional studies in large scale, a cheap, fast and efficient cloning vector is desired. Results A bifunctional vector pXST has been constructed. The pXST vector harbors a XcmI-ccdB-XcmI cassette and restriction site SmaI. Digestion the vector with XcmI generates a single thymidine (T) overhang at 3′ end which facilitates TA cloning, and SmaI gives blunt end that enables the blunt-end ligation. Multiple products with various sizes were amplified from cassava genome by PCR and each PCR fragment was separately cloned into a pXST using TA cloning and blunt-end ligation methods. In general, the TA cloning gave higher transformation efficiency than blunt-end ligation for inserts with all different sizes, and the transformation efficiency significantly decreased with increasing size of inserts. The highest transformation efficiency (8.6 × 106 transformants/μg) was achieved when cloning 517 bp DNA fragment using TA cloning. No significant difference observed in the positive cloning efficiency between two ligation methods and the positive cloning efficiency could reach as high as 100% especially for small inserts (e.g. 517 and 957 base pairs). Conclusions We describe a simple and general method to construct a novel pXST vector. We confirm the feasibility of using pXST vector to clone PCR products amplified from cassava genome with both TA cloning and blunt-end ligation methods. The pXST plasmid has several advantages over many currently available vectors in that (1) it possesses XcmI-ccdB-XcmI cassette and restriction site SmaI, enabling both TA cloning and blunt-end ligation. (2) it allows direct selection of positive recombinant plasmids in Escherichia coli through disruption of the ccdB gene. (3) it improves positive cloning efficiency by introducing the ccdB gene, reducing the possibility of self-ligation from insufficient digested plasmids. (4) it could be used by high performance and cost-effective cloning methods. Therefore, this dual function vector would offer flexible alternatives for gene cloning experiments to researchers

Appropriate LDL-C-to-HDL-C Ratio Cutoffs for Categorization of Cardiovascular Disease Risk Factors among Uygur Adults in Xinjiang, China

Elevated LDL-C/HDL-C ratio has been shown to be a marker of lipid metabolism as well as a good predictor of coronary artery disease (CAD). Thus, the aim of this study was to investigate whether the LDL-C/HDL-C ratio is useful for detecting cardiovascular disease (CVD) risk factors in general healthy Uygur adults in Xinjiang. A total of 4047 Uygur subjects aged ≥35 years were selected from the Cardiovascular Risk Survey (CRS) study which was carried out from October 2007 to March 2010. Anthropometric data, blood pressure, lipid profile and fasting glucose were measured in all participants. The prevalence, sensitivity, specificity and distance on the receiver operating characteristic (ROC) curve of each LDL-C/HDL-C ratio were calculated. The prevalence of high LDL-C and low HDL-C cholesterol was high and positively correlated with higher LDL-C/HDL-C ratio in the Uygur population. In both men and women, we detected a slight apparent trend of high prevalence of hypertension and hypercholesterolemia with higher LDL-C/HDL-C ratio. Our study also demonstrated that the discriminatory power of the LDL-C/HDL-C ratio for CVD risk factors was slightly stronger in men than in women. Analysis of the shortest distance in the ROC curves for hypertension, dyslipidemia, diabetes, or ≥two of these risk factors suggested a LDL-C/HDL-C ratio cutoff of 2.5 for both men and women. The results of this study showed that a LDL-C/HDL-C ratio cut-off of 2.5 might be used as the predictive marker to detect CVD risk factors among Uygur adults in Xinjiang