Matrix Formula of Differential Resultant for First Order Generic Ordinary Differential Polynomials

In this paper, a matrix representation for the differential resultant of two generic ordinary differential polynomials $f_1$ and $f_2$ in the differential indeterminate $y$ with order one and arbitrary degree is given. That is, a non-singular matrix is constructed such that its determinant contains the differential resultant as a factor. Furthermore, the algebraic sparse resultant of $f_1, f_2, \delta f_1, \delta f_2$ treated as polynomials in $y, y', y"$ is shown to be a non-zero multiple of the differential resultant of $f_1, f_2$. Although very special, this seems to be the first matrix representation for a class of nonlinear generic differential polynomials

Minimizing the surface effect of PDMS–glass microchip on polymerase chain reaction by dynamic polymer passivation

Polydimethyl siloxane (PDMS)–glass microchip has a very strong surface effect on polymerase chain reaction (PCR), leading to a very poor PCR yield. In the work reported here, practical dynamic passivation of surfaces of PDMS–glass microchip using polyethylene glycol (PEG) or polyvinylpyrrolidone (PVP) was achieved using a conventional thermocycler. The passivation procedure was cost-effective and easy to conduct. The effects of polymer molecular weight and polymer concentration on tube PCR efficiency were investigated primarily to prescreen out suitable polymers and polymer concentrations in the PCR mixture. The result from tube PCR indicated that both PEG and PVP could affect the performance of Taq polymerase. A final concentration of 0.025% (w/v) or 0.4% (w/v) polymer in the PCR mixture can enhance the tube PCR, while 1% (w/v) polymer was found to inhibit the reaction. PEG was more effective in tube PCR, although PVP performed better in chip PCR. Instead of employing the polymer directly in the PCR mixture, i.e. the conventional in situ passivation approach, another approach of dynamic passivation by pre-injecting polymers into the microchip achieved better performance. The efficiency of pre-passivation was found to follow the order: PVP10000>PVP55000, PEG8000> PEG10000>PEG400. After pre-passivation with PVP10000, PVP55000 and PEG8000, the PCR efficiency can recover to 93%, 86% and 83%, respectively, of that obtained from tube PCR. Copyright © 2006 Society of Chemical IndustryPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55877/1/1631_ftp.pd

Pseudogap, Superconducting Energy Scale, and Fermi Arcs in Underdoped Cuprate Superconductors

Through the measurements of magnetic field dependence of specific heat in $La_{2-x}Sr_xCuO_4$ in zero temperature limit, we determined the nodal slope $v_\Delta$ of the quasiparticle gap. It is found that $v_\Delta$ has a very similar doping dependence of the pseudogap temperature $T^*$ or value $\Delta_p$. Meanwhile the virtual maximum gap at ($\pi,0$) derived from $v_\Delta$ is found to follow the simple relation $\Delta_q=0.46k_BT^*$ upon changing the doping concentration. This strongly suggests a close relationship between the pseudogap and superconductivity. It is further found that the superconducting transition temperature is determined by both the residual density of states of the pseudogap phase and the nodal gap slope in the zero temperature limit, namely, $T_c \approx \beta v_\Delta \gamma_n(0)$, where $\gamma_n(0)$ is the extracted zero temperature value of the normal state specific heat coefficient which is proportional to the size of the residual Fermi arc $k_{arc}$. This manifests that the superconductivity may be formed by forming a new gap on the Fermi arcs near nodes below $T_c$. These observations mimic the key predictions of the SU(2) slave boson theory based on the general resonating-valence-bond (RVB) picture.Comment: 6 pages, 6 figures, to be published in Phys. Rev.

Overexpression of immunoglobulin G prompts cell proliferation and inhibits cell apoptosis in human urothelial carcinoma

Only B lymphocytes can express immunoglobulins according to the traditional immunological theories, and the expression of immunoglobulin G (IgG) messenger RNA (mRNA) and protein was found in certain human cancer cells recently. However, the expression pattern of IgG and its possible role in human urothelial carcinoma are still elusive. In this study, we investigated the expression of IgG in two human urothelial carcinoma cell lines, T24 and BIU-87, and in 56 cases of clinical urothelial carcinoma tissues. The mRNA of IgG was positively detected by in situ hybridization and reverse transcription PCR; furthermore, IgG protein was also positively detected by immunohistochemistry and Western blot. Moreover, blockade of tumor-derived IgG by either antihuman IgG antibody or antisense oligonucleotides increased cell apoptosis and inhibited cell growth in bladder cancer cell lines in vitro, and antihuman IgG antibody could suppress the growth of xenotransplant tumor in vivo. In addition, either antihuman IgG antibody or antisense oligonucleotides enhanced the sensitivity to mitomycin C in bladder cancer cell line T24. Furthermore, blockade of IgG in bladder cancer cell T24 resulted in upregulation of cleaved caspase-3 and cleaved poly(ADP-ribose) polymerase. Our results indicated that bladder cancer cells were capable of expressing IgG, and blockade of IgG expression induced cell apoptosis through activation of caspase-dependent pathway. A novel potential targeted therapy for bladder cancer will be possibly developed based on these data. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s13277-013-0717-z) contains supplementary material, which is available to authorized users

Scientometric trends and knowledge maps of global health systems research

Background: In the last few decades, health systems research (HSR) has garnered much attention with a rapid increase in the related literature. This study aims to review and evaluate the global progress in HSR and assess the current quantitative trends. Methods: Based on data from the Web of Science database, scientometric methods and knowledge visualization techniques were applied to evaluate global scientific production and develop trends of HSR from 1900 to 2012. Results: HSR has increased rapidly over the past 20 years. Currently, there are 28,787 research articles published in 3,674 journals that are listed in 140 Web of Science subject categories. The research in this field has mainly focused on public, environmental and occupational health (6,178, 21.46%), health care sciences and services (5,840, 20.29%), and general and internal medicine (3,783, 13.14%). The top 10 journals had published 2,969 (10.31%) articles and received 5,229 local citations and 40,271 global citations. The top 20 authors together contributed 628 papers, which accounted for a 2.18% share in the cumulative worldwide publications. The most productive author was McKee, from the London School of Hygiene \& Tropical Medicine, with 48 articles. In addition, USA and American institutions ranked the first in health system research productivity, with high citation times, followed by the UK and Canada. Conclusions: HSR is an interdisciplinary area. Organization for Economic Co-operation and Development countries showed they are the leading nations in HSR. Meanwhile, American and Canadian institutions and the World Health Organization play a dominant role in the production, collaboration, and citation of high quality articles. Moreover, health policy and analysis research, health systems and sub-systems research, healthcare and services research, health, epidemiology and economics of communicable and non-communicable diseases, primary care research, health economics and health costs, and pharmacy of hospital have been identified as the mainstream topics in HSR fields. These findings will provide evidence of the current status and trends in HSR all over the world, as well as clues to the impact of this popular topic; thus, helping scientific researchers and policy makers understand the panorama of HSR and predict the dynamic directions of research

A systemic administration of liposomal curcumin inhibits radiation pneumonitis and sensitizes lung carcinoma to radiation

Radiation pneumonitis (RP) is an important dose-limiting toxicity during thoracic radiotherapy. Previous investigations have shown that curcumin is used for the treatment of inflammatory conditions and cancer, suggesting that curcumin may prevent RP and sensitize cancer cells to irradiation. However, the clinical advancement of curcumin is limited by its poor water solubility and low bioavailability after oral administration. Here, a water-soluble liposomal curcumin system was developed to investigate its prevention and sensitizing effects by an intravenous administration manner in mice models. The results showed that liposomal curcumin inhibited nuclear factor-κB pathway and downregulated inflammatory factors including tumor necrosis factor-α, interleukin (IL)-6, IL-8, and transforming growth factor-β induced by thoracic irradiation. Furthermore, the combined treatment with liposomal curcumin and radiotherapy increased intratumoral apoptosis and microvessel responses to irradiation in vivo. The significantly enhanced inhibition of tumor growth also was observed in a murine lung carcinoma (LL/2) model. There were no obvious toxicities observed in mice. The current results indicate that liposomal curcumin can effectively mitigate RP, reduce the fibrosis of lung, and sensitize LL/2 cells to irradiation. This study also suggests that the systemic administration of liposomal curcumin is safe and deserves to be investigated for further clinical application

Enhancement of cisplatin sensitivity in lewis lung carcinoma by liposome-mediated delivery of a survivin mutant

<p>Abstract</p> <p>Background</p> <p>A high concentration of cisplatin (CDDP) induces apoptosis in many tumor cell lines. CDDP has been administered by infusion to avoid severe toxicity. Recently, it has been reported that changes in survivin expression or function may lead to tumor sensitization to chemical and physical agents. The aim of this study was to determine whether a dominant-negative mouse survivin mutant could enhance the anti-tumor activity of CDDP.</p> <p>Methods</p> <p>A plasmid encoding the phosphorylation-defective dominant-negative mouse survivin threonine 34→alanine mutant (survivin T34A) complexed to a DOTAP-chol liposome (Lip-mS) was administered with or without CDDP in Lewis Lung Carcinoma (LLC) cells and in mice bearing LLC tumors, and the effects on apoptosis, tumor growth and angiogenesis were assessed. Data were analyzed using one-way analysis of variance(ANOVA), and a value of <it>P </it>< 0.05 was considered to be statistically significant.</p> <p>Results</p> <p>LLC cells treated with a combination of Lip-mS and CDDP displayed increased apoptosis compared with those treated with Lip-mS or CDDP alone. In mice bearing LLC tumors and treated with intravenous injections of Lip-mS and/or CDDP, combination treatment significantly reduced the mean tumor volume compared with either treatment alone. Moreover, the antitumor effect of Lip-mS combined with CDDP was greater than their anticipated additive effects.</p> <p>Conclusion</p> <p>These data suggest that the dominant-negative survivin mutant, survivin T34A, sensitized LLC cells to chemotherapy of CDDP. The synergistic antitumor activity of the combination treatment may in part result from an increase in the apoptosis of tumor cells, inhibition of tumor angiogenesis and induction of a tumor-protective immune response.</p

Phylogeny and biogeography of Fagus (Fagaceae) based on 28 nuclear single/low-copy loci

Fagus L. is a key component in temperate deciduous broadleaf forests of the Northern Hemisphere. However, its biogeographic history has not been examined under the framework of a fully resolved and reasonably time-calibrated phylogeny. In this study, we sequenced 28 nuclear single/low-copy loci (18 555 bp in total) of 11 Fagus species/segregates and seven outgroups. Phylogenetic trees were reconstructed using both concatenation-based (maximum parsimony, maximum likelihood, and Bayesian inference) and coalescent-based methods (StarBEAST2, ASTRAL). The monophyly of two subgenera (Fagus and Engleriana) and most sections was well supported, except for sect. Lucida, which was paraphyletic with respect to sect. Longipetiolata. We also found a major phylogenetic conflict among North American, East Asian, and West Eurasian lineages of subgen. Fagus. Three segregates that have isolated distribution (F. mexicana, F. multinervis, and F. orientalis) were independent evolutionary units. Biogeographic analysis with fossils suggested that Fagus could have originated in the North Pacific region in late early Eocene. Major diversifications coincided with a climate aberration at the Eocene/Oligocene boundary and the global cooling since mid-Miocene. The late Miocene accelerated global cooling and the Pleistocene glaciations would have driven beeches into East Asia, North America, and West Eurasia. Meanwhile, range reduction and extinction in high latitudes, central Asia, and western North America converged to form the beech modern distribution pattern. This study provides a first attempt to disentangle the biogeographic history of beeches in the context of a nearly resolved and time-calibrated phylogeny, which could shed new insights into the formation of the temperate biome in the Northern Hemisphere.This work was supported by the National Natural Science Foundation of China (Grant Nos. 31770236, 30760016, and 31560064) and the Strategic Priority Research Program of Chinese Academy of Sciences (XDB31000000).1 Introduction 2 Material and Methods 2.1 Taxon sampling 2.2 Screening of nuclear single/low-copy orthologous locus 2.3 DNA extraction, PCR protocol, and sequencing 2.4 Phylogenetic analyses and molecular dating 2.5 Ancestral area reconstruction 3 Results 3.1 Concatenated tree 3.2 Species tree and molecular dating 3.3 Ancestral area reconstruction 4 Discussion 4.1 Nearly resolved and well supported phylogeny of Fagus 4.2 Species delimitation of three segregates within Fagus 4.3 Biogeographic history of beech species Acknowledgement