151 research outputs found

    First Experimental Demonstration of Gate-all-around III-V MOSFET by Top-down Approach

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    The first inversion-mode gate-all-around (GAA) III-V MOSFETs are experimentally demonstrated with a high mobility In0.53Ga0.47As channel and atomic-layer-deposited (ALD) Al2O3/WN gate stacks by a top-down approach. A well-controlled InGaAs nanowire release process and a novel ALD high-k/metal gate process has been developed to enable the fabrication of III-V GAA MOSFETs. Well-behaved on-state and off-state performance has been achieved with channel length (Lch) down to 50nm. A detailed scaling metrics study (S.S., DIBL, VT) with Lch of 50nm - 110nm and fin width (WFin) of 30nm - 50nm are carried out, showing the immunity to short channel effects with the advanced 3D structure. The GAA structure has provided a viable path towards ultimate scaling of III-V MOSFETs.Comment: IEEE IEDM 2011 pp. 769-772; Structures are valuable for low-dimensional physics stud

    Herb-resistant UPEC strains have different biofilm formation abilities and different expression of certain biofilm related genes

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    Background: The mechanisms and patterns of drug resistances of E. coli strains that cause uncomplicated urinary tract infections (UTIs) vary considerably. The emerging herbresistance of uropathogenic Escherichia coli (UPEC) has been a serious health problem, yet with unknown underlying mechanisms.Methods: To explore the potential herb-resistance mechanisms of E. coli strains that cause uncomplicated UTIs, three clinically isolated herb-resistant UPEC strains (1351, 4996, 5028) were analyzed for their abilities to form biofilms and the expressions of the pga ABCD and luxS genes.Results: We found that the expression of pgaA and pgaB are very different between 1351 and 5028, and the loss-offunction of luxS in 4996 has impact on biofilm formation.Conclusions: 1. Herb-resistance of the strains is related to their abilities of biofilm formation. 2. Biofilm formation capabilities of herb-resistant strains show different responses to the presence of glucose. 3. luxS encoded AI-2 is not essential for biofilm formation in this strain but may help with more biofilm formation.Keywords: Herb-resistance; Biofilm formation; Uropathogenic Escherichia coli (UPEC); pga ABCD; lux

    Ameliorative Effect and Underlying Mechanisms of Total Triterpenoids from Psidium guajava Linn (Myrtaceae) Leaf on High-Fat Streptozotocin-induced Diabetic Peripheral Neuropathy in Rats

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    Purpose: To investigate whether the total triterpenoids extracted from Psidium Guajava leaves (TTPGL) attenuate the development of diabetic peripheral neuropathy in rats by regulating the NF-κB pathway of the inflammatory process and its signaling mediators.Methods: All the Sprague Dawley rats used were maintained in a clean environment on a 12 h light/12h dark cycle. High-fat feeding and intraperitoneal injection of 40 mg/kg streptozotocin (STZ) were used to induce diabetes in the rats. The rats were randomly divided into 5 groups: diabetic mellitus (DM) group; TTPGL - 30 group, TTPGL - 60 group and TTPGL - 120 group treated by intragastric administration (i.g) with 30, 100 and 120 mg/kg/day TTPGL, respectively. The well-established drug, rosiglitazone (RSG, 3 mg/k/d, i.g.), was used as positive control. Normal rats served as control group. Nerve conduction velocity and sensitive tests were measured on weeks 1, 4 and 8. After 8 weeks administration, expression of pro-inflammatory molecules (TNF - α, IL - 6 and iNOS) and tissue proteins (Akt, IKKα, and NF – κB - p65) were evaluated to assess biochemical changes.Results: Compared to DM group, TTPGL (especially 120 mg / kg dose) treatment improved (p < 0.05) physical functions and provided neuronal protection in high - fat/streptozotocin - induced peripheral neuropathy rats. We found that the expressions of several pro - inflammatory factors such as tumor necrosis factor - α (TNF - α), IL - 6 and inducible nitric oxide synthase (iNOS) were highly suppressed (p < 0.05 or p < 0.01) by TTPGL in sciatic nerve. Mechanism analysis indicated that the ameliorative effect of TTPGL, in part, is through suppression of the expression of pro - inflammatory cytokines by NF - κB pathway mediation.Conclusion: TTPGL offers a potential therapeutic approach for the treatment of diabetic peripheral neuropathy.Keywords: Triterpenoids, Psidium Guajava, Diabetic peripheral neuropathy, Pro inflammatory cytokines, NF-κB pathwa

    MICROORGANISMS FROM HANDS OF TRADITIONAL CHINESE MEDICAL DOCTORS IN A CENTRAL HOSPITAL ENVIRONMENT

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    Background: In a central hospital, the heavy clinical workload makes one to overlook its hazard to health and can to a large extent promote the transmission of pathogenic microorganisms. It is not uncommon however, to observe practices that deviate from normal standards of hygiene. Hand contact between doctors of TCM and patients may lead to nosocomial infections. Materials and Methods: Samples were sourced and collected from hands of TCM doctors in a central hospital. The fungal isolates were identified by colonial morphology and microscopic examination. Sensitivity test were performed on each of the identified isolates using the Multiple Disc Diffusion method. Results: A total of 265 samples were collected from the fingers, palm and back of hands of TCM doctors. Seven organisms were isolated, with S. aureus being the most common bacterium with frequency of 55.9% in the hospital environment. Other bacteria isolated included P. aeruginosa, E. coli and K. aerogenes. S. cerevisae was the most common fungus isolated with frequency of 61.8%. Fungi isolated included P. chrysogenum and A. niger. Conclusion: The study showed clearly that hand contact between TCM doctors and patients may lead to infection of exposed susceptible patients. Results of antibiotic susceptibility pattern show that isolates in this study are mostly resistant to augmentin and most antibiotics of old generation, while gentamycin and pefloxacin were highly active against most of isolates. Considering the possibility of transmission of contamination, special attention should be directed towards disinfection of TCM doctors’ hands

    HERB-RESISTANT UPEC STRAINS HAVE DIFFERENT BIOFILM FORMATION ABILITIES AND DIFFERENT EXPRESSION OF CERTAIN BIOFILM RELATED GENES

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    Background: The mechanisms and patterns of drug resistances of E. coli strains that cause uncomplicated urinary tract infections (UTIs) vary considerably. The emerging herbresistance of uropathogenic Escherichia coli (UPEC) has been a serious health problem, yet with unknown underlying mechanisms. Methods: To explore the potential herb-resistance mechanisms of E. coli strains that cause uncomplicated UTIs, three clinically isolated herb-resistant UPEC strains (1351, 4996, 5028) were analyzed for their abilities to form biofilms and the expressions of the pga ABCD and luxS genes. Results: We found that the expression of pgaA and pgaB are very different between 1351 and 5028, and the loss-offunction of luxS in 4996 has impact on biofilm formation. Conclusions: 1. Herb-resistance of the strains is related to their abilities of biofilm formation. 2. Biofilm formation capabilities of herb-resistant strains show different responses to the presence of glucose. 3. luxS encoded AI-2 is not essential for biofilm formation in this strain but may help with more biofilm formation

    Thingking and utilization technology of coalbed methane in soft and low permeability coal seams in Huainan Mining Area

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    In order to solve the problems that restrict the efficient development of coalbed methane resources under the conditions of soft and low permeability outburst coal seams in Huainan Mining Area, such as complex coal seam structure, multi-source gas emission, rapid decline of drainage flow, high rock roadway and drilling costs, and low (ultra-low) concentration coalbed methane utilization rate, six key technologies suitable for the coordinated development mode of coal and coalbed methane under the condition of coal seam group mining in Huainan mining area are put forward, namely: coalbed methane extraction technology of ground level staged fracturing wells, shield rapid construction technology of coalbed methane extraction roadways, enhanced extraction technology of underground soft coalbed methane, coalbed methane extraction technology of pressure relief in ground mining area, the construction technology of "replacing roadways with holes", and cascade utilization technology of low concentration coalbed methane. The application of supporting key technologies shows that staged fracturing technology and refined drainage and production technology of roof horizontal wells in broken and soft coal seam have effectively improved the pre pumping production of coalbed methane; The full face hard rock roadheader in deep coal mine roadway greatly improves the roadway excavation efficiency, realizing the automation and less humanization of hard rock excavation; Sand adding of hydraulic fracturing and ultra-high hydraulic slotting have realized pressure relief and permeability enhancement in large areas underground coal mine; Type III and IV surface mining area wells can replace the roof high drainage roadway in the treatment of pressure relief gas in coal seam group mining, and reduce the coalbed methane drainage intensity of other measures; The technology of "replacing roadways with holes" has significantly improved the quality of successful directional drilling at middle and high levels in complex roof; Cascade utilization technology of low concentration coalbed methane has greatly reduced the emission of coalbed methane. The six key technologies have guaranteed the safe production in Huainan mining area, and comprehensively improved the output of coal and coalbed methane and the utilization level of coalbed methane. Six key technologies ensure the safe production in Huainan mining area, and comprehensively improved the output of coal and coalbed methane and the utilization level of coalbed methane. Finally, in view of the problems such as high operation cost, low production, small scope of hydraulic fracturing coal reservoir reconstruction technology for surface horizontal wells, and the risk of breakage of mining wells, and small scale of cascade utilization of ultra-low concentration coalbed methane, the development direction of deep CBM precise geological guidance, super large scale efficient reservoir volume transformation, pumping effect evaluation technology, stable and continuous pumping technology of surface wells in mining areas, underground large area intelligent hydraulic enhanced permeability technology, "one well with multiple uses" collaborative pumping CBM technology, and full concentration CBM comprehensive utilization technology are proposed
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