1,511 research outputs found
Lactobacillus rhamnosus confers protection against colorectal cancer in rats
Purpose: To investigate the protective effect and mechanism of action of Lactobacillus rhamnosus against colorectal cancer (CRC).
Methods: A total of 40 healthy female Sprague Dawley rats weighing 100 â 140 g (mean weight = 120 ± 20 g) were used for this study. The rats were randomly assigned to four groups of 10 rats each: normal control group, L. rhamnosus group; 1, 2-dimethylhydrazine (DMH) group and treatment group. Rats in L. rhamnosus group were inoculated with L. rhamnosus (1 x 108 CFU/mL) orally for 20 weeks, while rats in DMH group received 35 mg DMH/kg /week intraperitoneally for 10 weeks for induction of CRC. Treatment group rats received 35 mg DMH/kg bwt intraperitoneally for 10 weeks for induction of CRC, and were treated with L. rhamnosus (1 x 108 CFU/mL) orally for 20 weeks. After 20 weeks, the rats were euthanized using ether anesthesia. Expressions of inflammatory, angiogenesis and proapoptotic genes were determined using Western blotting and real-time quantitative polymerase chain reaction (qRT-PCR).
Results: Treatment with L. rhamnosus significantly reduced the incidence of CRC in the rats (p < 0.05). The incidence of multiple tumors in the treatment group was also significantly reduced, when compared to DMH group (p < 0.05). The protein expressions of inducible nitric oxide synthase (iNOS), tumor necrosis factor α (TNF-α), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), cyclooxygenase-2 (COX-2), bcl-2 and vascular endothelial growth factor α (VEGF-α) were significantly upregulated in DMH group, when compared with normal control group (p < 0.05). However, treatment with L. rhamnosus significantly down-regulated the expressions of these proteins (p < 0.05). DMH treatment also significantly upregulated the expressions of iNOS, TNF-α, VEGF-α, NF-kB, ÎČ-catenin and bax genes (p < 0.05). However, L. rhamnosus significantly reversed the effects of DMH on the expression levels of these genes (p < 0.05).
Conclusion: These results show that L. rhamnosus prevents CRC via suppression of expressions of inflammatory and angiogenesis genes, and upregulation of apoptotic gene expression
Multiple Model Rao-Blackwellized Particle Filter for Manoeuvring Target Tracking
Particle filters can become quite inefficient when applied to a high-dimensional state space since a prohibitively large number of samples may be required to approximate the underlying density functions with desired accuracy. In this paper, a novel multiple model Rao-Blackwellized particle filter (MMRBPF)-based algorithm has been proposed for manoeuvring target tracking in a cluttered environment. The advantage of the proposed approach is that the Rao-Blackwellization allows the algorithm to be partitioned into target tracking and model selection sub-problems, where the target tracking can be solved by the probabilistic data association filter, and the model selection by sequential importance sampling. The analytical relationship between target state and model is exploited to improve the efficiency and accuracy of the proposed algorithm. Moreover, to reduce the particle-degeneracy problem, the resampling approach is selectively carried out. Finally, experiment results, show that the proposed algorithm, has advantages over the conventional IMM-PDAF algorithm in terms of robust and efficiency.Defence Science Journal, 2009, 59(3), pp.197-204, DOI:http://dx.doi.org/10.14429/dsj.59.151
Goal-Driven Process Navigation for Individualized Learning Activities in Ubiquitous Networking and IoT Environments
Abstract: In the study, we propose an integrated adaptive framework to support and facilitate individualized learning through sharing the successful process of learning activities based on similar learning patterns in the ubiquitous learning environments empowered by Internet of Things (IoT). This framework is based on a dynamic Bayesian network that gradually adapts to a target student's needs and information access behaviours. By analysing the log data of learning activities and extracting students' learning patterns, our analysis results show that most of students often use their preferred learning patterns in their learning activities, and the learning achievement is affected by the learning process. Based on these findings, we try to optimise the process of learning activities using the extracted learning patterns, infer the learning goal of target students, and provide a goal-driven navigation of individualized learning process according to the similarity of the extracted learning patterns
Organizational factors influencing for the success of ERP implementation
Enterprise Resource Planning (ERP) systems link together entire organization's operations. The success of ERP
implementation depends not only on the technology but also on many organizational factors. This study identifies the
organizational factors influencing the success of ERP system. The study found that the success of ERP
implementation depends on several organizational elements. According to research findings, these can be categorized
into three main elements: Alignment of ERP with the business process, Transferring ERP know-how to end users and
Promoting ERP acceptance in the user organizatio
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Rapidly Evolving R Genes in Diverse Grass Species Confer Resistance to Rice Blast Disease
We show that the genomes of maize, sorghum, and brachypodium contain genes that, when transformed into rice, confer resistance to rice blast disease. The genes are resistance genes (R genes) that encode proteins with nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domains (NBSâLRR proteins). By using criteria associated with rapid molecular evolution, we identified three rapidly evolving R-gene families in these species as well as in rice, and transformed a randomly chosen subset of these genes into rice strains known to be sensitive to rice blast disease caused by the fungus Magnaporthe oryzae. The transformed strains were then tested for sensitivity or resistance to 12 diverse strains of M. oryzae. A total of 15 functional blast R genes were identified among 60 NBSâLRR genes cloned from maize, sorghum, and brachypodium; and 13 blast R genes were obtained from 20 NBSâLRR paralogs in rice. These results show that abundant blast R genes occur not only within species but also among species, and that the R genes in the same rapidly evolving gene family can exhibit an effector response that confers resistance to rapidly evolving fungal pathogens. Neither conventional evolutionary conservation nor conventional evolutionary convergence supplies a satisfactory explanation of our findings. We suggest a unique mechanism termed âconstrained divergence,â in which R genes and pathogen effectors can follow only limited evolutionary pathways to increase fitness. Our results open avenues for R-gene identification that will help to elucidate R-gene vs. effector mechanisms and may yield new sources of durable pathogen resistance.Organismic and Evolutionary Biolog
Microfluidic chip-based valveless flow injection analysis system with gravity-driven flows
In this work, a microfluidic chip-based valveless flow injection analysis (FIA) system with gravity-driven flows and liquid-core waveguide (LCW) spectrometric detection was developed. Automated sample injection in the 0.3-6.4 nL range under gated injection mode was achieved by controlling the vertical position of the waste reservoir fixed on a moving platform and the residence time of the reservoir in each position, without the requirement of microvalves or electrokinetic manipulation. An integrated LCW spectrometric detection system was built on the chip by coupling a 20 mm-long Teflon AF 2400 capillary with the microchannel to function as a LCW flow cell, using a green LED as light source and a photodiode as detector. The performance of the system was demonstrated in the determination o
Effects of Sangu Decoction on Osteoclast Activity in a Rat Model of Breast Cancer Bone Metastasis
Bone metastasis (BM) is a major clinical problem for which current treatments lack full efficacy. The Traditional Chinese Medicine (TCM) Sangu Decoction (SGD) has been widely used to treat BM in China. However, no in vivo experiments to date have investigated the effects of TCM on osteoclast activity in BM. In this study, the protective effect and probable mechanism of SGD were evaluated. The model was established using the breast cancer MRMT-1 cells injected into the tibia of rat. SGD was administrated, compared with Zoledronic acid as a positive control. The development of the bone tumor and osteoclast activity was monitored by radiological analysis. TRAP stain was used to identify osteoclasts quantity and activity. TRAP-5b in serum or bone tumor and TRAP mRNA were also quantified. Radiological examination showed that SGD inhibited tumor proliferation and preserved the cortical and trabecular bone structure. In addition, a dramatic reduction of TRAP positive osteoclasts was observed and TRAP-5b levels in serum and bone tumor decreased significantly. It also reduced the mRNA expression of TRAP. The results indicated that SGD exerted potent antiosteoclast property that could be directly related to its TRAP inhibited activity. In addition it prevented bone tumor proliferation in BM model
LSMR: An iterative algorithm for sparse least-squares problems
An iterative method LSMR is presented for solving linear systems and
least-squares problem \min \norm{Ax-b}_2, with being sparse or a fast
linear operator. LSMR is based on the Golub-Kahan bidiagonalization process. It
is analytically equivalent to the MINRES method applied to the normal equation
A\T Ax = A\T b, so that the quantities \norm{A\T r_k} are monotonically
decreasing (where is the residual for the current iterate
). In practice we observe that \norm{r_k} also decreases monotonically.
Compared to LSQR, for which only \norm{r_k} is monotonic, it is safer to
terminate LSMR early. Improvements for the new iterative method in the presence
of extra available memory are also explored.Comment: 21 page
Comparative studies on the multi-component pharmacokinetics of Aristolochiae Fructus and honey-fried Aristolochiae Fructus extracts after oral administration in rats
PK parameters of 7-OH AA I in rats after oral administration of AF and HAF. (DOC 37ĂÂ kb
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