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71.
Ecoinformatics using wireless sensor networks: An overview 总被引:1,自引:0,他引:1
Wireless sensor networks have the potential to become significant subsystems of ecological experiment. Sensor networks consist of large number of tiny sensor nodes, all of which have sensing capabilities. These networks allow coordinated signal detection, monitoring, and tracking to enable sensor nodes to simultaneously capture geographically distinct measurements. Sensor nodes do not require predetermined positioning making such networks especially useful for applications in remote, inhospitable environments. In this paper we have tried to see the various ecological experimental scenarios, and how wireless sensor networks can be used in that field. One of the most challenging bottlenecks in the usage of wireless sensor networks in large scale experiments is the energy constraint. Various routing protocols which have tried to optimize the energy usage are also studied in the paper. 相似文献
72.
The pre-irradiation combustion (PC) of samples to liberate iodine, followed by trapping the iodine on charcoal and quantifying
the element by neutron activation analysis (NAA), has been used at the National Institute of Standards and Technology for
the determination of iodine in biological materials. The applicability of this technique to numerous environmental and dietary
matrices is illustrated by analysis of a range of certified reference materials (CRMs) and a powdered grass material that
was prepared as an in-house reference material (RM). Because of the combustion step involved, samples with low or no fat content
(e.g., cereal products, selected botanical specimens, and nonfat milk powder) and inorganic materials (e.g., coal fly ash
and dried sediments) are more suited for analysis by this method. In general, the results for several types of samples obtained
by this method agreed with those obtained by a second radiochemical (R) NAA, as well as by a third method using inductively
coupled plasma mass spectrometry (ICP-MS). PC-NAA is a useful technique for determining iodine in biological and environmental
samples, especially for verification of iodine results obtained from other methods. 相似文献
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Leung W Iyengar R Leimig T Holladay MS Houston J Handgretinger R 《Cancer immunology, immunotherapy : CII》2005,54(4):389-394
Infection, disease relapse, graft failure, and graft-versus-host disease (GVHD) are significant adverse events associated with allogeneic bone marrow transplantation. Donor natural killer (NK) cells may be an ideal cell type for prevention or treatment of all these adverse events. Therefore, we investigated the phenotype and function of human NK cells purified by using a clinical-scale immunomagnetic method. We found that the NK cell purification procedures did not adversely affect the expression of killer cell immunoglobulin-like receptors, adhesion molecules, intracellular cytokines, perforin, and granzyme B. Purified NK cells had extensive proliferative capacity and potent antitumor activity when assessed using an immunodeficient mouse model. While all mice transplanted with unpurified mononuclear cells developed GVHD, none of the mice transplanted with purified NK cells did. NK cells were highly susceptible to lysis by antithymocyte globulin (ATG), whereas G-CSF had a minimal effect on their natural cytotoxicity. These results support future clinical investigation of the use of purified NK cells for adoptive immunotherapy in the absence of ATG. 相似文献
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Derek A Ruths Luay Nakhleh M Sriram Iyengar Shrikanth A G Reddy Prahlad T Ram 《Journal of computational biology》2006,13(9):1546-1557
Biological signaling networks comprise the chemical processes by which cells detect and respond to changes in their environment. Such networks have been implicated in the regulation of important cellular activities, including cellular reproduction, mobility, and death. Though technological and scientific advances have facilitated the rapid accumulation of information about signaling networks, utilizing these massive information resources has become infeasible except through computational methods and computer-based tools. To date, visualization and simulation tools have received significant emphasis. In this paper, we present a graph-theoretic formalization of biological signaling network models that are in wide but informal use, and formulate two problems on the graph: the Constrained Downstream and Minimum Knockout Problems. Solutions to these problems yield qualitative tools for generating hypotheses about the networks, which can then be experimentally tested in a laboratory setting. Using established graph algorithms, we provide a solution to the Constrained Downstream Problem. We also show that the Minimum Knockout Problem is NP-Hard, propose a heuristic, and assess its performance. In tests on the Epidermal Growth Factor Receptor (EGFR) network, we find that our heuristic reports the correct solution to the problem in seconds. Source code for the implementations of both solutions is available from the authors upon request. 相似文献
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R‐loop induced stress response by second (p)ppGpp synthetase in Mycobacterium smegmatis: functional and domain interdependence 下载免费PDF全文
Sushma Krishnan Anushya Petchiappan Albel Singh Apoorva Bhatt Dipankar Chatterji 《Molecular microbiology》2016,102(1):168-182
Persistent R‐loops lead to replicative stress due to RNA polymerase stalling and DNA damage. RNase H enzymes facilitate the organisms to survive in the hostile condition by removing these R‐loops. MS_RHII‐RSD was previously identified to be the second (p)ppGpp synthetase in Mycobacterium smegmatis. The unique presence of an additional RNase HII domain raises an important question regarding the significance of this bifunctional protein. In this report, we demonstrate its ability to hydrolyze R‐loops in Escherichia coli exposed to UV stress. MS_RHII‐RSD gene expression was upregulated under UV stress, and this gene deleted strain showed increased R‐loop accumulation as compared to the wild type. The domains in isolation are known to be inactive, and the full length protein is required for its function. Domain interdependence studies using active site mutants reveal the necessity of a hexamer form with high alpha helical content. In previous studies, bacterial RNase type HI has been mainly implicated in R‐loop hydrolysis, but in this study, the RNase HII domain containing protein showed the activity. The prospective of this differential RNase HII activity is discussed. This is the first report to implicate a (p)ppGpp synthetase protein in R‐loop‐induced stress response. 相似文献
80.
The berries of the plant Anamirta cocculus afforded picrotin, picrotoxinin, methyl picrotoxate and two new sesquiterpene γ-lactones, dihydroxypicrotoxinin and picrotoxic acid, whose structures were determined by spectroscopic methods. 相似文献