1,492 research outputs found

    Insulated ECG electrodes

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    Insulated, capacitively coupled electrode does not require electrolyte paste for attachment. Other features of electrode include wide range of nontoxic material that may be employed for dielectric because of sputtering technique used. Also, electrode size is reduced because there is no need for external compensating networks with FET operational amplifier

    Insulated electrocardiographic electrodes

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    An integrated system is disclosed including an insulated electrode and an impedance transformer which can be assembled in a small plastic housing and used for the acquisition of electrocardiographic data. The electrode may be employed without a paste electrolyte and may be attached to the body for extended usage without producing skin reaction. The electrode comprises a thin layer of suitable nontoxic dielectric material preferably deposited by radio frequency sputtering onto a conductive substrate. The impedance transformer preferably comprises an operational amplifier having an FET input stage connected in the unity gain configuration which provides a very low lower cut-off frequency, a high input impedance with a very small input bias current, a low output impedance, and a high signal-to-noise ratio

    The development of insulated electrocardiogram electrodes

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    An integrated system was developed, consisting of an insulated electrode and an impedance transformer, which can be used for the acquisition of electrocardiographic data. The electrode consists of a thin layer of dielectric material deposited onto a silicon substrate. The impedance transformer is an operational amplifier used in the unity gain configuration. Both electrode and impedance transformer are contained in a plastic housing identical to that used with the NASA Apollo-type electrode. The lower cut off frequency of the electrode system is between 0.01 and 1.0 Hz, depending on the dielectric used and its thickness. Clinical quality electrocardiograms were obtained with these electrodes

    Partially linear censored quantile regression

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    Censored regression quantile (CRQ) methods provide a powerful and flexible approach to the analysis of censored survival data when standard linear models are felt to be appropriate. In many cases however, greater flexibility is desired to go beyond the usual multiple regression paradigm. One area of common interest is that of partially linear models: one (or more) of the explanatory covariates are assumed to act on the response through a non-linear function. Here the CRQ approach of Portnoy (J Am Stat Assoc 98:1001–1012, 2003) is extended to this partially linear setting. Basic consistency results are presented. A simulation experiment and unemployment example justify the value of the partially linear approach over methods based on the Cox proportional hazards model and on methods not permitting nonlinearity

    Patterns of Pathogenesis: Discrimination of Pathogenic and Nonpathogenic Microbes by the Innate Immune System

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    The dominant conceptual framework for understanding innate immunity has been that host cells respond to evolutionarily conserved molecular features of pathogens called pathogen-associated molecular patterns (PAMPs). Here, we propose that PAMPs should be understood in the context of how they are naturally presented by pathogens. This can be experimentally challenging, since pathogens, almost by definition, bypass host defense. Nevertheless, in this review, we explore the idea that the immune system responds to PAMPs in the context of additional signals that derive from common “patterns of pathogenesis” employed by pathogens to infect, multiply within, and spread among their hosts

    RNA Interference Analysis of Legionella in Drosophila Cells: Exploitation of Early Secretory Apparatus Dynamics

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    Legionella pneumophila translocates multiple bacterial effector proteins into host cells to direct formation of a replication vacuole for the bacterium. The emerging consensus is that formation of this compartment involves recruitment of membrane material that traffics between the endoplasmic reticulum (ER) and Golgi. To investigate this model, a targeted approach was used to knock down expression of proteins involved in membrane trafficking, using RNA interference in Drosophila cells. Surprisingly, few single knockdowns of ER–Golgi transport proteins decreased L. pneumophila replication. By analyzing double-stranded RNAs in pairs, combinations were identified that together caused defects in intracellular replication, consistent with the model that membrane traffic funnels into the replication vacuole from multiple sources. In particular, simultaneous depletion of the intermediate compartment and Golgi-tethering factor transport protein particle together with the ER SNARE protein Sec22 reduced replication efficiency, indicating that introduction of lesions at distinct sites in the secretory system reduces replication efficiency. In contrast to knockdowns in secretory traffic, which required multiple simultaneous hits, knockdown of single cytosolic components of ER-associated degradation, including Cdc48/p97 and associated cofactors, was sufficient to inhibit intracellular replication. The requirement for the Cdc48/p97 complex was conserved in mammalian cells, in which replication vacuoles showed intense recruitment of ubiquitinated proteins, the preferred substrates of Cdc48/p97. This complex promoted dislocation of both ubiquitinated proteins and bacterial effectors from the replication vacuole, consistent with the model that maintenance of high-level replication requires surveillance of the vacuole surface. This work demonstrates that L. pneumophila has the ability to gain access to multiple sites in the secretory system and provides the first evidence for a role of the Cdc48/p97 complex in promoting intracellular replication of pathogens and maintenance of replication vacuoles

    Biomarker analysis beyond angiogenesis: RAS/RAF mutation status, tumour sidedness, and second-line ramucirumab efficacy in patients with metastatic colorectal carcinoma from RAISE-a global phase III study

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    Carcinoma colorrectal; Ramucirumab; BRAFCarcinoma colorrectal; Ramucirumab; BRAFColorectal carcinoma; Ramucirumab; BRAFBackground Second-line treatment with ramucirumab+FOLFIRI improved overall survival (OS) versus placebo+FOLFIRI for patients with metastatic colorectal carcinoma (CRC) [hazard ratio (HR)=0.84, 95% CI 0.73–0.98, P = 0.022]. Post hoc analyses of RAISE patient data examined the association of RAS/RAF mutation status and the anatomical location of the primary CRC tumour (left versus right) with efficacy parameters. Patients and methods Patient tumour tissue was classified as BRAF mutant, KRAS/NRAS (RAS) mutant, or RAS/BRAF wild-type. Left-CRC was defined as the splenic flexure, descending and sigmoid colon, and rectum; right-CRC included transverse, ascending colon, and cecum. Results RAS/RAF mutation status was available for 85% of patients (912/1072) and primary tumour location was known for 94.4% of patients (1012/1072). A favourable and comparable ramucirumab treatment effect was observed for patients with RAS mutations (OS HR = 0.86, 95% CI 0.71–1.04) and patients with RAS/BRAF wild-type tumours (OS HR = 0.86, 95% CI 0.64–1.14). Among the 41 patients with BRAF-mutated tumours, the ramucirumab benefit was more notable (OS HR = 0.54, 95% CI 0.25–1.13), although, as with the other genetic sub-group analyses, differences were not statistically significant. Progression-free survival (PFS) data followed the same trend. Treatment-by-mutation status interaction tests (OS P = 0.523, PFS P = 0.655) indicated that the ramucirumab benefit was not statistically different among the mutation sub-groups, although the small sample size of the BRAF group limited the analysis. Addition of ramucirumab to FOLFIRI improved left-CRC median OS by 2.5 month over placebo (HR = 0.81, 95% CI 0.68–0.97); median OS for ramucirumab-treated patients with right-CRC was 1.1 month over placebo (HR = 0.97, 95% CI 0.75–1.26). The treatment-by-sub-group interaction was not statistically significant for tumour sidedness (P = 0.276). Conclusions In the RAISE study, the addition of ramucirumab to FOLFIRI improved patient outcomes, regardless of RAS/RAF mutation status, and tumour sidedness. Ramucirumab treatment provided a numerically substantial benefit in BRAF-mutated tumours, although the P-values were not statistically significant.This work was supported by Eli Lilly and Company. No grant number is applicable

    CP and related phenomena in the context of Stellar Evolution

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    We review the interaction in intermediate and high mass stars between their evolution and magnetic and chemical properties. We describe the theory of Ap-star `fossil' fields, before touching on the expected secular diffusive processes which give rise to evolution of the field. We then present recent results from a spectropolarimetric survey of Herbig Ae/Be stars, showing that magnetic fields of the kind seen on the main-sequence already exist during the pre-main sequence phase, in agreement with fossil field theory, and that the origin of the slow rotation of Ap/Bp stars also lies early in the pre-main sequence evolution; we also present results confirming a lack of stars with fields below a few hundred gauss. We then seek which macroscopic motions compete with atomic diffusion in determining the surface abundances of AmFm stars. While turbulent transport and mass loss, in competition with atomic diffusion, are both able to explain observed surface abundances, the interior abundance distribution is different enough to potentially lead to a test using asterosismology. Finally we review progress on the turbulence-driving and mixing processes in stellar radiative zones.Comment: Proceedings of IAU GA in Rio, JD4 on Ap stars; 10 pages, 7 figure

    Centerscope

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    Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.

    Gene expression in developing watermelon fruit

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    <p>Abstract</p> <p>Background</p> <p>Cultivated watermelon form large fruits that are highly variable in size, shape, color, and content, yet have extremely narrow genetic diversity. Whereas a plethora of genes involved in cell wall metabolism, ethylene biosynthesis, fruit softening, and secondary metabolism during fruit development and ripening have been identified in other plant species, little is known of the genes involved in these processes in watermelon. A microarray and quantitative Real-Time PCR-based study was conducted in watermelon [<it>Citrullus lanatus </it>(Thunb.) Matsum. & Nakai var. lanatus] in order to elucidate the flow of events associated with fruit development and ripening in this species. RNA from three different maturation stages of watermelon fruits, as well as leaf, were collected from field grown plants during three consecutive years, and analyzed for gene expression using high-density photolithography microarrays and quantitative PCR.</p> <p>Results</p> <p>High-density photolithography arrays, composed of probes of 832 EST-unigenes from a subtracted, fruit development, cDNA library of watermelon were utilized to examine gene expression at three distinct time-points in watermelon fruit development. Analysis was performed with field-grown fruits over three consecutive growing seasons. Microarray analysis identified three hundred and thirty-five unique ESTs that are differentially regulated by at least two-fold in watermelon fruits during the early, ripening, or mature stage when compared to leaf. Of the 335 ESTs identified, 211 share significant homology with known gene products and 96 had no significant matches with any database accession. Of the modulated watermelon ESTs related to annotated genes, a significant number were found to be associated with or involved in the vascular system, carotenoid biosynthesis, transcriptional regulation, pathogen and stress response, and ethylene biosynthesis. Ethylene bioassays, performed with a closely related watermelon genotype with a similar phenotype, i.e. seeded, bright red flesh, dark green rind, etc., determined that ethylene levels were highest during the green fruit stage followed by a decrease during the white and pink fruit stages. Additionally, quantitative Real-Time PCR was used to validate modulation of 127 ESTs that were differentially expressed in developing and ripening fruits based on array analysis.</p> <p>Conclusion</p> <p>This study identified numerous ESTs with putative involvement in the watermelon fruit developmental and ripening process, in particular the involvement of the vascular system and ethylene. The production of ethylene during fruit development in watermelon gives further support to the role of ethylene in fruit development in non-climacteric fruits.</p
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