815 research outputs found

    Localized-Surface-Plasmon Enhanced the 357 nm Forward Emission from ZnMgO Films Capped by Pt Nanoparticles

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    The Pt nanoparticles (NPs), which posses the wider tunable localized-surface-plasmon (LSP) energy varying from deep ultraviolet to visible region depending on their morphology, were prepared by annealing Pt thin films with different initial mass-thicknesses. A sixfold enhancement of the 357 nm forward emission of ZnMgO was observed after capping with Pt NPs, which is due to the resonance coupling between the LSP of Pt NPs and the band-gap emission of ZnMgO. The other factors affecting the ultraviolet emission of ZnMgO, such as emission from Pt itself and light multi-scattering at the interface, were also discussed. These results indicate that Pt NPs can be used to enhance the ultraviolet emission through the LSP coupling for various wide band-gap semiconductors

    Liner Exchange Into A Well Fixed Acetabular Shell In Revision Total Hip Arthroplasty

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    OBJECTIVE To investigate clinical outcomes and complications of isolated polyethylene liner exchange for revision total hip arthroplasty. METHODS From April 1 995 to December 2007, 80 patients (93 hips) underwent revision total hip arthroplasty during which only polyethylene liner was exchanged with reservation of acetabular cup. There were 41 males and 39 females, aged from 27 to 82 years (average, 53.3 years). The duration from the primary THA to the revision surgery ranged from 0.3 to 18.4 years (average, 10.9 years). The reasons for liner exchange included: polyethylene wear with osteolysis (78 hips), polyethylene wear without osteolysis (5 hips), polyethylene wear with stem loosening (4 hips), recurrent dislocation (3 hips), infection (1 hip), periprosthetic fracture (1 hip) and liner dislodgement (1 hip). Forty-seven liners were fixed into the old cup using cement, and 46 were fixed with the original locking mechanism. Sixty cross-linked polyethylene liners and 33 conventional polyethylene liners were used. RESULTS All patients were followed up for 5 to 15 years (average, 7 years). The average Harris hip score improved from preoperative 86.0±16.9 to 89.4±11.6 at final follow-up. Complications included dislocation (10 hips), infection (2 hips), periprosthetic fracture (1 hip) and liner dislodgement (1 hip). Ten hips underwent rerevision due to different reasons: cup exchange (5 hips), conventional polyethylene wear (2 hips), infection (2 hips) and liner dislodgement (1 hip). Using component loosening as the end point, the 10-year survival rate was 100% in the cement fixation group and 84.8% in the original locking group. Using rerevision as the end point, the 10-year survival rate was 90.4% in the cement fixation group and 65.0% in the original locking group. CONCLUSION Liner exchange either with cement or original locking mechanism is a safe and successful method. Highly cross-linked polyethylene has a higher wear resistance, which can reduce incidence of osteolysis and improve survival rate of prosthesis.目的探討保留髖臼杯更換聚乙烯襯墊在全髖關節翻修術中的作用.方法1995年4月至2007年12月,80例(93髖)接受保留髖臼杯更換聚乙烯襯墊手術.男41例,女39例;年齡2782歲,平均53.3歲.初次置換與更換襯墊手術間隔0.318.4年,平均10.9年.翻修原因:聚乙烯磨損及骨溶解78髖,聚乙烯接近完全磨損但無骨溶解5髖,聚乙烯磨損及股骨柄假體鬆動4髖,復發性關節脫位3髖,感染1髖,假體周圍骨折1髖,襯墊脫位1髖.翻修襯墊採用高交聯聚乙烯60髖、普通聚乙烯33髖,以骨水泥固定47髖、原鎖定機制固定46髖.結果隨訪515年,平均7年.術前Harris髖關節評分(86.0±16.9)分,終末隨訪時(89.4±11.6)分.並發症包括脫位10髖,感染2髖,假體周圍骨折1髖,襯墊脫落1髖.10髖再次翻修:髖臼杯翻修5髖,普通聚乙烯磨損2髖,感染2髖,襯墊脫落1髖.普通聚乙烯組新發骨溶解12髖.以假體鬆動為終點,十年生存率骨水泥固定組100%、原鎖定機制固定組84.8 %;以再次翻修為終點,十年生存率分別為90.4%和65.0%.結論以骨水泥或原鎖定機制固定翻修襯墊均安全有效.高交聯聚乙烯耐磨性較好,能降低骨溶解風險,假體存活率更高

    STUDY ON TOTAL LUMINESCENCE SPECTRA - APPLICATION OF THE MONTE-CARLO METHOD TO 3-DIMENSIONAL SYNCHRONOUS FLUORESCENCE SPECTROMETRY

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    Three-dimensional synchronous fluorescence spectrometry (TDSFS, a combination of synchronous fluorescence spectrometry and three-dimensional fluorescence spectrometry) is a new method which has been developed recently. The method has usually been used as an efficient tool to select the best Delta lambda value for synchronous fluorescence spectra. This paper studies the sensitivity of the method, which was not been done in the past. The total fluorescence intensity has been used instead of the conventional single point intensity, calculated by the Monte-Carlo method, as the experimental parameter to determine fluorescein and tryptophan. The sensitivity of the total fluorescence method is nearly one hundred times better than that of the single point method. The new method has been used to simultaneously determine naphthalene, pyrene and perylene successfully. The mechanism of the method has also been studied

    Phase Separation and Magnetic Order in K-doped Iron Selenide Superconductor

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    Alkali-doped iron selenide is the latest member of high Tc superconductor family, and its peculiar characters have immediately attracted extensive attention. We prepared high-quality potassium-doped iron selenide (KxFe2-ySe2) thin films by molecular beam epitaxy and unambiguously demonstrated the existence of phase separation, which is currently under debate, in this material using scanning tunneling microscopy and spectroscopy. The stoichiometric superconducting phase KFe2Se2 contains no iron vacancies, while the insulating phase has a \surd5\times\surd5 vacancy order. The iron vacancies are shown always destructive to superconductivity in KFe2Se2. Our study on the subgap bound states induced by the iron vacancies further reveals a magnetically-related bipartite order in the superconducting phase. These findings not only solve the existing controversies in the atomic and electronic structures in KxFe2-ySe2, but also provide valuable information on understanding the superconductivity and its interplay with magnetism in iron-based superconductors

    Selection of reference genes for gene expression studies in ultraviolet B-irradiated human skin fibroblasts using quantitative real-time PCR

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    <p>Abstract</p> <p>Background</p> <p>Reference genes are frequently used to normalise mRNA levels between different samples. The expression level of these genes, however, may vary between tissues or cells and may change under certain circumstances. Cytoskeleton genes have served as multifunctional tools for experimental studies as reference genes. Our previous studies have demonstrated that the expression of vimentin, one cytoskeletal protein, was increased in ultraviolet B (UVB)-irradiated fibroblasts. Thus, we examined the expression of other cytoskeleton protein genes, <it>ACTB </it>(<it>actin, beta</it>), <it>TUBA1A </it>(<it>tubulin, alpha 1a</it>), and <it>TUBB1 </it>(<it>tubulin, beta 1</it>), in human dermal fibroblasts irradiated by UVB to determine which of these candidates were the most appropriate reference genes.</p> <p>Results</p> <p>Quantitative real-time PCR followed by analysis with the NormFinder and geNorm software programmes was performed. The initial screening of the expression patterns demonstrated that the expression of <it>VIM </it>was suppressed after UVB irradiation at doses ≥25 mJ/cm<sup>2 </sup>and that the expression of <it>TUBA1A </it>was significantly reduced by UVB doses ≥75 mJ/cm<sup>2 </sup>in cultured human dermal fibroblasts. The analysis of the experimental data revealed <it>ACTB </it>to be the most stably expressed gene, followed by <it>GAPDH </it>(<it>aglyceraldehyde-3-phosphate dehydrogenase</it>), under these experimental conditions. By contrast, <it>VIM </it>was found to be the least stable gene. The combination of <it>ACTB </it>and <it>TUBB1 </it>was revealed to be the gene pair that introduced the least systematic error into the data normalisation.</p> <p>Conclusion</p> <p>The data herein provide evidence that <it>ACTB </it>and <it>TUBB1 </it>are suitable reference genes in human skin fibroblasts irradiated by UVB, whereas <it>VIM </it>and <it>TUBA1A </it>are not and should therefore be excluded as reference genes in any gene expression studies involving UVB-irradiated human skin fibroblasts.</p

    Loss of LMOD1 impairs smooth muscle cytocontractility and causes megacystis microcolon intestinal hypoperistalsis syndrome in humans and mice

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    Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a congenital visceral myopathy characterized by severe dilation of the urinary bladder and defective intestinal motility. The genetic basis of MMIHS has been ascribed to spontaneous and autosomal dominant mutations in actin gamma 2 (ACTG2), a smooth muscle contractile gene. However, evidence suggesting a recessive origin of the disease also exists. Using combined homozygosity mapping and whole exome sequencing, a genetically isolated family was found to carry a premature termination codon in Leiomodin1 (LMOD1), a gene preferentially expressed in vascular and visceral smooth muscle cells. Parents heterozygous for the mutation exhibited no abnormalities, but a child homozygous for the premature termination codon displayed symptoms consistent with MMIHS. We used CRISPR-Cas9 (CRISPR-associated protein) genome editing of Lmod1 to generate a similar premature termination codon. Mice homozygous for the mutation showed loss of LMOD1 protein and pathology consistent with MMIHS, including late gestation expansion of the bladder, hydronephrosis, and rapid demise after parturition. Loss of LMOD1 resulted in a reduction of filamentous actin, elongated cytoskeletal dense bodies, and impaired intestinal smooth muscle contractility. These results define LMOD1 as a disease gene for MMIHS and suggest its role in establishing normal smooth muscle cytoskeletal-contractile coupling

    Follow-Up of Patients with Multidrug Resistant Tuberculosis Four Years after Standardized First-Line Drug Treatment

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    Background: In 2004, an anti-tuberculosis (TB) drug resistance survey in Heilongjiang province, China, enrolled 1574 (79%) new and 421 (21%) retreatment patients. Multi-drug resistant (MDR) TB was detected in 7.2% of new and 30.4% of retreatment patients. All received treatment with standardized first-line drug (FLD) regimens. Methodology/Principal Findings: We report treatment outcomes of the 2004 cohort, and long-term outcomes as assessed in the second half of 2008. The reported cure rate for MDR-TB patients was 83% (94/113) among new and 66% (85/128) among retreatment patients (P<0.001). Ten of the 241 MDR-TB patients died during treatment. Of the remaining 231, 129 (56%) could be traced in 2008. The overall recurrence rates among new and retreatment cases were 46% and 66%, respectively (P=0.03). The overall death rates among new and retreatment cases were 25% and 46%, respectively (P=0.02). Forty percent of the traced new cases and 24% of the retreatment cases were alive and without recurrent TB (P=0.01). Of the 16 patients who failed or defaulted from treatment in 2004, only two patients were not re-diagnosed with TB by 2008. Of the 111 (86%) patients with an initial successful treatment outcome 63 (57%) had developed recurrent TB, 40 (36%) had died, 27 (24%) of them died of TB. The follow-up period of four years precluded follow-up of all patients. In a highly conservative sensitivity analysis in which we assumed that all non-included patients were alive and did not have recurrent TB, the recurrence and death rate were 33% and 21%. Conclusions/Significance: Documentation of cure based on conventional smear microscopy was a poor predictor of long term outcomes. MDR-TB patients in Heilongjiang province in China had high recurrence and death rates four years after treatment with standardized FLD regimens, reinforcing the need for early diagnosis and treatment of MDR-TB, including assessment of treatment outcomes with more sensitive laboratory method

    Hydrothermal Synthesis, Microstructure and Photoluminescence of Eu3+-Doped Mixed Rare Earth Nano-Orthophosphates

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    Eu3+-doped mixed rare earth orthophosphates (rare earth = La, Y, Gd) have been prepared by hydrothermal technology, whose crystal phase and microstructure both vary with the molar ratio of the mixed rare earth ions. For LaxY1–xPO4: Eu3+, the ion radius distinction between the La3+ and Y3+ is so large that only La0.9Y0.1PO4: Eu3+ shows the pure monoclinic phase. For LaxGd1–xPO4: Eu3+ system, with the increase in the La content, the crystal phase structure of the product changes from the hexagonal phase to the monoclinic phase and the microstructure of them changes from the nanorods to nanowires. Similarly, YxGd1–xPO4: Eu3+, Y0.1Gd0.9PO4: Eu3+ and Y0.5Gd0.5PO4: Eu3+ samples present the pure hexagonal phase and nanorods microstructure, while Y0.9Gd0.1PO4: Eu3+ exhibits the tetragonal phase and nanocubic micromorphology. The photoluminescence behaviors of Eu3+ in these hosts are strongly related to the nature of the host (composition, crystal phase and microstructure)
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