1,577 research outputs found

    A 0.8 V T Network-Based 2.6 GHz Downconverter RFIC

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    A 2.6 GHz downconverter RFIC is designed and implemented using a 0.18 μm CMOS standard process. An important goal of the design is to achieve the high linearity that is required in WiMAX systems with a low supply voltage. A passive T phase-shift network is used as an RF input stage in a Gilbert cell to reduce supply voltage. A single supply voltage of 0.8 V is used with a power consumption of 5.87 mW. The T network-based downconverter achieves a conversion gain (CG) of 5 dB, a single-sideband noise figure (NF) of 16.16 dB, an RF-to-IF isolation of greater than 20 dB, and an input-referred third-order intercept point (IIP3) of 1 dBm when the LO power of -13 dBm is applied

    Cloning, purification, and functional characterization of Carocin S2, a ribonuclease bacteriocin produced by Pectobacterium carotovorum

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    <p>Abstract</p> <p>Background</p> <p>Most isolates of <it>Pectobacterium carotovorum subsp. carotovorum </it>(Pcc) produce bacteriocins. In this study, we have determined that Pcc strain F-rif-18 has a chromosomal gene encoding the low-molecular-weight bacteriocin, Carocin S2, and that this bacteriocin inhibits the growth of a closely related strain. Carocin S2 is inducible by ultraviolet radiation but not by mutagenic agents such as mitomycin C.</p> <p>Results</p> <p>A carocin S2-defective mutant, TF1-2, was obtained by Tn5 insertional mutagenesis using F-rif-18. A 5706-bp DNA fragment was detected by Southern blotting, selected from a genomic DNA library, and cloned to the vector, pMS2KI. Two adjacent complete open reading frames within pMS2KI were sequenced, characterized, and identified as caroS2K and caroS2I, which respectively encode the killing protein and immunity protein. Notably, carocin S2 could be expressed not only in the mutant TF1-2 but also in <it>Escherichia coli </it>DH5α after entry of the plasmid pMS2KI. Furthermore, the C-terminal domain of CaroS2K was homologous to the nuclease domains of colicin D and klebicin D. Moreover, SDS-PAGE analysis showed that the relative mass of CaroS2K was 85 kDa and that of CaroS2I was 10 kDa.</p> <p>Conclusion</p> <p>This study shown that another nuclease type of bacteriocin was found in <it>Pectobacterium carotovorum</it>. This new type of bacteriocin, Carocin S2, has the ribonuclease activity of CaroS2K and the immunity protein activity of CaroS2I.</p

    Spatial modelling and mapping of teen birth rates in Taiwan in the period 1995-2010

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    Geographical variations in teen birth rates (TBR) still persist despite controlling for contextual factors. The aim of this research was to identify spatial patterns of TBR in Taiwan and to examine spatial relationships among different contextual factors. Using townships as the unit of analysis (N=359), this research used social and demographic variables for the years 1995, 2000, 2005 and 2010 and conducted spatial modelling of TBR. Geographical maps of TBR were presented, and Local Indicator of Spatial Autocorrelations was used to identify TBR clustering. Comparisons were made between ordinary least-squares models and spatial lag models, in which township-level TBRs were regressed on other township-level contextual characteristics. Our study found that townships with a high TBR were mostly in eastern, central and some southern regions of Taiwan, while townships with a low TBR were in the vicinity of metropolitan areas. The significant spatial lag indicated that townships would have a higher expected prevalence rate if adjacent townships have had higher rates. Results also indicated that the percentage of aborigines and the percentage of college-educated people were consistently associated with TBR over the years. Interventions aimed at reducing TBR in Taiwan should consider the presence of spatial correlations and should incorporate neighbouring townships

    A screen-printed carbon electrode modified with a chitosan-based film for in situ heavy metal ions measurement

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    SEM images and FTIR data of the working electrode surface showed that Mn+ ions were adsorbed on chitosan (Chit) and crosslinked chitosan-carbon nanotube (Chit-CNT) films. XPS revealed that chelation of Mn+ ions with the –NH2/–OH groups from chitosan, –COOH group from carbon nanotubes, and aqua ligands represents a possible structure of the active Mn+ species in the Chit-based film. The electrochemical behaviors of the Chit-based film modified screen-printed carbon electrode (SPCE) were characterized for individual and simultaneous detection of Cu2+, Pb2+, Hg2+, Zn2+, Cd2+, and As3+ ions. For individual detection, the concentration range was 0.50–3.00 ppm with a detection limit of 0.4 ppm for Cu2+; 1.0–4.0 ppm with a detection limit of 0.5 ppm for Pb2+; 1.0–5.0 ppm with a detection limit of 0.8 ppm for Hg2+. For simultaneous detection, the lab chip sensor was successfully used to determine the concentrations of Pb2+, Cu2+, Hg2+, and As3+ ions simultaneously

    Contextual factors and spatial patterns of childhood malnutrition in provinces of Burkina Faso

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    Background: Approximately 45% of all children's deaths are associated with malnutrition, and sub-Saharan Africa is hardest hit by this phenomenon. However, information on geographical variations of malnutrition in developing countries is limited. This study examined the geographical distribution and community characteristics associated with child malnutrition in Burkina Faso. Design: Data from the 2011 Burkina Faso Demographic Health Survey were analyzed. A general Kriging interpolation method was used to generate spatial malnutrition patterns. The global Moran's I test was used to identify significant malnutrition spatial patterns. Generalized estimating equations (GEEs) were fitted to examine the association between community level factors and malnutrition. Results: Average rates of stunting and wasting in the communities were 32.48% and 15.05%, respectively. Stunting hotspots were observed in the eastern and northeastern parts of Burkina Faso (i.e. Oudolan, Séno and Yagha, among others), while high rates of wasting were observed in the north-central part. The GEE results revealed lower stunting rates in communities with a higher percentage of households with improved sanitation. Communities with higher rates of professionally assisted births were associated with low wasting rates, while communities with higher rates of households with a low wealth index reported higher rates of wasting. Conclusions: Spatial statistical models of malnutrition prevalence are useful for indicating hotspots over wide areas and hence, for guiding intervention strategies. This study revealed significant geographical patterns and community factors associated with childhood malnutrition. These factors should be considered in future programs aimed at reducing malnutrition in Burkina Faso

    Infectious Alopecia in a Dog Breeder After Renal Transplantation

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    Tinea capitis rarely occurs in renal transplant recipients. We report this living-related renal transplant patient receiving cyclosporine-based therapy who initially presented with severe exfoliation of the scalp with yellowish-white scales and marked hair loss. The lesions extended to the frontal area and both cheeks, resulting in several skin ulcers with perifocal erythematous inflammatory changes, and palpable cervical lymph nodes. A biopsy of a skin lesion revealed fungal infection and culture yielded Microsporum canis. The patient mentioned an outbreak of ringworm in her breeding dogs during this period. After adequate treatment of the patient and her infected animals with griseofulvin and disinfection of the environment, her skin lesions resolved dramatically, with regrowth of hair

    Does Long-Term Use of Silver Nanoparticles Have Persistent Inhibitory Effect on H. pylori Based on Mongolian Gerbil’s Model?

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    It is urgent to find alternative agents due to increasing failure rate of Helicobacter pylori (H. pylori) eradication. The study surveyed the long-term effect of silver nanoparticles (AgNP) on H. pylori based on Mongolian gerbil's model

    Decision Theory-Based COI-SNP Tagging Approach for 126 Scombriformes Species Tagging

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    The mitochondrial gene cytochrome c oxidase I (COI) is commonly used for DNA barcoding in animals. However, most of the COI barcode nucleotides are conserved and sequences longer than about 650 base pairs increase the computational burden for species identification. To solve this problem, we propose a decision theory-based COI SNP tagging (DCST) approach that focuses on the discrimination of species using single nucleotide polymorphisms (SNPs) as the variable nucleotides of the sequences of a group of species. Using the example of 126 teleost mackerel fish species (order: Scombriformes), we identified 281 SNPs by alignment and trimming of their COI sequences. After decision rule making, 49 SNPs in 126 fish species were determined using the scoring system of the DCST approach. These COI-SNP barcodes were finally transformed into one-dimensional barcode images. Our proposed DCST approach simplifies the computational complexity and identifies the most effective and fewest SNPs to resolve or discriminate species for species tagging

    Phyllanthus urinaria Induces Apoptosis in Human Osteosarcoma 143B Cells via Activation of Fas/FasL- and Mitochondria-Mediated Pathways

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    Phyllanthus urinaria (P. urinaria), in this study, was used for the treatment of human osteosarcoma cells, which is one of the tough malignancies with few therapeutic modalities. Herein, we demonstrated that P. urinaria inhibited human osteosarcoma 143B cells growth through an apoptotic extrinsic pathway to activate Fas receptor/ligand expression. Both intracellular and mitochondrial reactive oxygen species were increased to lead to alterations of mitochondrial membrane permeability and Bcl-2 family including upregulation of Bid, tBid, and Bax and downregulation of Bcl-2. P. urinaria triggered an intrinsic pathway and amplified the caspase cascade to induce apoptosis of 143B cells. However, upregulation of both intracellular and mitochondrial reactive oxygen species and the sequential membrane potential change were less pronounced in the mitochondrial respiratory-defective 143Bρ0 cells compared with the 143B cells. This study offers the evidence that mitochondria are essential for the anticancer mechanism induced by P. urinaria through both extrinsic and intrinsic pathways

    Endoscopic Balloon Dilatation for Esophageal Strictures in Children Younger Than 6 Years: Experience in a Medical Center

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    Esophageal strictures in children may be caused by congenital anomaly, caustic agent or foreign body ingestion, complication of reflux esophagitis, and after esophageal surgery. Accidental ingestion of alkaline fluid is the most common cause of corrosive esophagitis in children in Taiwan. In this article, we studied 10 pediatric patients who had esophageal strictures and required endoscopic balloon dilatation (EBD) therapy under general anesthesia from January 2003 to June 2009. The median age of the studied children who received their first EBD treatment was 36.2 months (13.4–60.9 months), with a dilator size of 8.0mm (5–12 mm). The interval between injury and initial EBD was 3.0 months (1.3–60.8 months). The treatment duration averaged 16.7 months (3.0–69.3 months), with 13.5 (4–31) instances of EBD therapy per patient. The greater the length of stricture, the more number of times EBD was needed. In these cases, no severe complication was found after the procedure. The result indicated that EBD under general anesthesia was a safe and effective method to resolve the symptom of dysphagia and diet condition. Because of the limited number of study cases, long-term studies are required to further confirm the clinical effect of EBD under general anesthesia
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