Positivity of Continuous-Time Descriptor Systems With Time Delays

This technical note is concerned with positivity characteristic of continuous-time descriptor systems with time delays. First, a set of necessary and sufficient conditions is presented to check the property. Then, considering a descriptor time-delay system with two assumptions, a new time-delay system is established whose positivity is equivalent to that of the original system. Furthermore, a set of necessary and sufficient conditions is provided to check the positivity of the new system. Finally, a numerical example is given to illustrate the validity of the results obtained

New tumor-targeted nanosized delivery carrier for oligonucleotides: characteristics in vitro and in vivo

Tianyang Zhou1,2, Xin Jia1, Huixiang Li3, Jin Wang3, Hongling Zhang1,2, Youmei A1,2, Zhenzhong Zhang1,21School of Pharmaceutical Sciences, 2Nanotechnology Research Center for Drugs, 3Department of Pathology, Medical School of Zhengzhou University, Zhengzhou, People’s Republic of ChinaBackground: The purpose of this study was to investigate the in vitro and in vivo characteristics of a new tumor-targeted nanosized delivery carrier for antisense oligonucleotide (ASON).Methods: Polyethylenimine (PEI) was used to condense ASON to form nanosized complexes (PEI/ASON), which were then modified using asparagine-glycine-arginine (NGR) peptide to obtain a tumor-targeted nanosized delivery carrier (NGR/PEI/ASON). The conditions required to form PEI/ASON were investigated.Results: A linear correlation between the natural logarithm of the N/P ratio (PEI to ASON) and the zeta potential of the PEI/ASON complexes was found, ranging from 1.5 to 5.0. The pH of the solution strongly influenced the zeta potential of the PEI/ASON complexes. PEI/ASON and NGR/PEI/ASON were stable in RPMI-1640 culture medium in the presence of Dextran 70. Incorporation of ASON into PEI/ASON and NGR/PEI/ASON complexes prevented degradation of ASON by DNase I.Conclusion: Both ASON/PEI and NGR/PEI/ASON complexes enhanced the uptake of ASON by EC9706 cells in vitro. In vivo, NGR/PEI/ASON complexes had the ability to target tumor tissues effectively.Keywords: nanosized delivery system, squamous cell carcinoma, antisense oligonucleotid

Purification and characterization of an antimicrobial protein from Gastrodia elata Blume tubers

Purpose: To purify and characterize a novel antimicrobial protein from the Gastrodia elata Blume (Bl.) plant, which has long been used in herbal medicine.Methods: The procedure for isolation and purification of Gastrodia elata protein (GEP) involved phosphate buffer extraction, ammonium sulfate precipitation, ion-exchange chromatography, and gelfiltration chromatography. Sodium dodecyl sulfate - polyacrylamide gel electrophoresis was employed to detect the apparent molecular mass and determine homogeneity, while paper disc diffusion was used to measure the antibacterial activity of GEP. A hemolytic assay was performed on rabbit red blood cells. The effect of pH, salt concentration, and temperature on the antibacterial activity of GEP was evaluated by minimum inhibitory concentration assay.Results: GEP was a 14-kDa monomer and displayed antimicrobial activity against Staphylococcus aureus and Candida albicans, with 8.0-mm and 9.4-mm zones of inhibition, respectively, but no antibacterial activity was observed against Escherichia coli. GEP had little hemolytic activity on red blood cells even at a concentrations of up to 200 mg/ml. GEP was thermally stable at temperatures below 70 °C for 30 min, and displayed higher antibacterial activity in the pH range 5.0 to 7.0.Conclusion: GEP protein is relatively thermostable and possesses antimicrobial activity. The results suggest that GEP protein has potential agricultural and industrial applications, such as in transgenic plants.Keywords: Antimicrobial protein, Gastrodia elata, Protein characterizatio

Bounded real lemmas for positive descriptor systems

A well known result in the theory of linear positive systems is the existence of positive definite diagonal matrix (PDDM) solutions to some well known linear matrix inequalities (LMIs). In this paper, based on the positivity characterization, a novel bounded real lemma for continuous positive descriptor systems in terms of strict LMI is first established by the separating hyperplane theorem. The result developed here provides a necessary and sufficient condition for systems to possess H?H? norm less than ? and shows the existence of PDDM solution. Moreover, under certain condition, a simple model reduction method is introduced, which can preserve positivity, stability and H?H? norm of the original systems. An advantage of such method is that systems? matrices of the reduced order systems do not involve solving of LMIs conditions. Then, the obtained results are extended to discrete case. Finally, a numerical example is given to illustrate the effectiveness of the obtained results

Adjuvant chemotherapy of megestrol acetate in advanced breast cancer: A meta-analysis

To evaluate the effectiveness and safety of adjuvant chemotherapy of megestrol acetate (MA) in advanced breast cancer, we searched CBM, CNKI, VIP, Wangfang Data and PubMed, and collected randomized controlled trials (RCT) of adjuvant chemotherapy of MA in advanced breast cancer. MA significantly increased treatment efficiency (p=0.0010); improve weight (p<0.0001), appetite (p=0.001) and KPS (p=0.06); ameliorate leucopenia (p=0.02), thrombocytopenia (p=0.02) and hemoglobin (p=0.01); reduce gastrointestinal reaction (p=0.0005) of the patients of adjuvant chemotherapy in advanced breast cancer. MA significantly increased treatment efficiency, improve the nutritional situation, reduce bone marrow suppression, and gastrointestinal reaction of the patients of adjuvant chemotherapy in advanced breast cancer. High-quality RCTs are needed to guidance for preliminary studies of the effective treatment of adjuvant chemotherapy of MA in advanced breast cancer.

Estimates on compressed neural networks regression

When the neural element number nn of neural networks is larger than the sample size mm, the overfitting problem arises since there are more parameters than actual data (more variable than constraints). In order to overcome the overfitting problem, we propose to reduce the number of neural elements by using compressed projection AA which does not need to satisfy the condition of Restricted Isometric Property (RIP). By applying probability inequalities and approximation properties of the feedforward neural networks (FNNs), we prove that solving the FNNs regression learning algorithm in the compressed domain instead of the original domain reduces the sample error at the price of an increased (but controlled) approximation error, where the covering number theory is used to estimate the excess error, and an upper bound of the excess error is given

Leukocyte Antigen-Related Protein Tyrosine Phosphatase Receptor: A Small Ectodomain Isoform Functions as a Homophilic Ligand and Promotes Neurite Outgrowth

The identities of ligands interacting with protein tyrosine phosphatase (PTP) receptors to regulate neurite outgrowth remain mainly unknown. Analysis of cDNA and genomic clones encoding the rat leukocyte common antigen-related (LAR) PTP receptor predicted a small, approximately 11 kDa ectodomain isoform, designated LARFN5C, containing a novel N terminal followed by a C-terminal segment of the LAR fifth fibronectin type III domain. RT-PCR and Northern blot analysis confirmed the presence of LARFN5C transcripts in brain. Transfection of COS cells with LARFN5C-Fc cDNA resulted in expression of the predicted protein, and Western blot analysis verified expression of approximately 11 kDa LARFN5C protein in vivo and its developmental regulation. Beads coated with rLARFN5C demonstrated aggregation consistent with homophilic binding, and pull-down and immunoprecipitation assays demonstrated that rLARFN5C associates with the LAR receptor. rLARFN5C binding to COS cells was dependent on LAR expression, and rLARFN5C binding to LAR +/+ hippocampal neurons was fivefold greater than that found by using LAR-deficient (-/-) neurons. Substratum-bound rLARFN5C had potent neurite-promoting effects on LAR +/+ neurons, with a fivefold loss in potency with the use of LAR -/- neurons. rLARFN5C in solution at low nanomolar concentrations inhibited neurite outgrowth induced by substratum-bound rLARFN5C, consistent with receptor-based function. These studies suggest that a small ectodomain isoform of a PTP receptor can function as a ligand for the same receptor to promote neurite outgrowth