[Effects of probiotics on the intestinal microecological abnormalities and colorectal cancer of mice induced by high-fat diet].

Objective: To establish the mice colorectal cancer (CRC) model induced by AOM/DSS with the intervention of high fat diet and probiotics, and to explore the potential mechanism of probiotics intervention in regulating intestinal flora disturbance and antitumor efficiency. Methods: Forty 8-week-old male C57BL/6J mice were randomly divided into 4 groups with 10 mice in each group: HFD group, HDF with probiotics intervention (HFD+P) group, normal diet (ND) group, normal diet with probiotics intervention (ND+P) group. The probiotic groups were administered with probiotics preparation by gavage. During the experiment, AOM/DSS was used to induce mouse colorectal cancer model. The mouse body weight was regularly recorded and the body status was evaluated weekly. High-throughput 16S rDNA sequencing was used to analyze the changes of fecal flora in bacterial structure before and after cancer induction. At the end of the experiment, intestinal tissues of mice were collected and the epididymis adipose mass (EAM) and tumor burden were recorded. The Alpha diversity index was used to analyze the abundance and diversity of the intestinal flora (higher chaol index means higher abundance of bacteria and greater Simpson index means lower diversity in flora structure). The Beta diversity index was used to analyze the significance of the difference in the distribution of intestinal flora among the four groups (When R>0, the difference in the distribution of bacteria among the groups is greater than the difference within the group). Results: After 15 weeks of experiment, the body weight of mice in HFD group, HFD+P group, ND group and ND+P group was (33.70±0.52) g, (28.70±0.32) g, (25.90±0.34) g and (25.60±0.40) g, whose difference was statistically significant (F=700.89, P<0.01). The body weight of HFD group was higher than that of ND group and HFD+P group while the body weight of HFD+P group was still higher than that of ND group, and the differences were statistically significant (all P<0.017). The average EAM of HFD group, HFD+P group, ND group and ND+P group was (1.36±0.15) g, (0.67±0.08) g, (0.58±0.10) g and (0.54±0.05) g, whose difference was statistically significant (F=114.03, P<0.01). Pairwise comparisons showed that EAM in HFD group was higher than that in ND group and HFD+P group respectively, with statistically significant difference (both P<0.01), while average EAM of HFD+P group was similar to ND group (P=0.09). Under the diet intervention, the Chao1 index of HFD group, HFD+P group, ND group and ND+P group was 217.62, 235.32, 301.51 and 305.71 respectively, and the Simpson index was 0.93, 0.89, 0.91 and 0.90. At the same time, the Anosim analysis of Beta diversity analysis showed that the difference in the flora distribution among four groups was greater than the difference with in each group with statistically significant difference (R=0.655, P=0.001). Species abundance analysis revealed that, compared with ND group, at phylum level, HFD group had a higher proportion of Bacteroides phylum and Firmicutes phylum in the intestinal flora and lower proportion of Verrucomicrobia; at genus level, the proportion of Bacteroides and Oscillibacter in HFD group was higher while the proportion of Akkermansia and Alloprevotella was lower. After the intervention of probiotics, the flora mentioned above was improved significantly except for Alloprevotella. The average number of tumor in HFD group, HFD+P group, ND group and ND+P group was 4.63±1.19, 2.33±0.52, 2.56±0.73 and 2.38±0.52 with statistically significant difference (F=14.92, P<0.01). Conclusion: Probiotics therapy can reduce obesity and flora imbalance caused by HFD and reduce the incidence of CRC by regulating intestinal flora disturbance.

Chemical synthesis of Nd2Fe14B/Fe3B nanocomposites.

High exchange-coupled Nd2Fe14B/Fe3B nanocomposites were synthesized by an integrative procedure of thermal decomposition and reductive annealing processes. The molar ratio of the resulting products of Nd/Fe/B can be tuned by adjusting the raw material proportion. The as-prepared nanocomposites exhibited an exchanged coupled effect with a large coercivity of 11 100 Gs, enhanced remanence Mr of 42.0 emu g(-1), and Mr/M3T of 0.59.

Error-free image compression algorithm using classifying-sequencing techniques.

The development of a new error-free digital image compression algorithm is discussed. Without the help of any statistics information of the images being processed, this algorithm achieves average bits-per-word ratios near the entropy of the neighboring pixel differences. Because this algorithm does not involve statistical modeling, generation of a code book, or long integer-floating point arithmetics, it is simpler and, therefore, faster than the studied statistics codes, such as the Huffman code or the arithmetic code.

STM imaging of molecular collagen and phospholipid membranes.

The application of STM to biological materials has been limited by poor conductivity, sample geometry and stability of biological materials. In this paper we describe an STM study of the monomeric helical forms of collagen, a stable, conductive and widely prevalent structural protein. We have also used STM to image artificial Langmuir DPE (dipalmitoyl phosphatidyl ethanolamine) phospholipid membranes. Both molecular collagen and the phospholipid membranes were dried in air on highly oriented pyrolytic graphite (HOPG). Our STM images of collagen dried on HOPG reveal strands 15 A in diameter with a periodicity of about 30 A which correlates with that known to occur in collagen. Spikes which periodically protrude from strands in our STM images of collagen appear to represent pyrrolidine ring structures in the amino acids proline and hydroxyproline. Thus, we report the first STM imaging of native biomolecules revealing intramolecular details and what appear to be specific amino acids. STM imaging of phospholipid membranes show a lattice pattern with densities spaced approximately 4.5 A apart. These are thought to represent individual phospholipid molecules in an artificial membrane formed on the HOPG. We believe STM and its related technologies will have great future utility in biomolecular studies.