聚甲基丙烯酸甲酯強化和修復椎弓根螺釘的生物力學研究

Objective To evaluate pedicle screw fixation strength following augmentation and restoration with polymethylmethacrylate (PMMA). Methods Compact CD (CCD) screws of 6.0 mm diameter was implanted into the pedicle unilaterally. And a pilot hole was created using 3.5 mm drill contralaterally on eight fresh human lower lumbar vertebrae (L 3-5).Neither the screws nor the drillings penetrated the anterior cortex of the vertebral bodies. The screws were pulled out from the vertebrae at 5 mm/min. The screw track and the pilot hole were filled with 3-5 ml of PMMA. Then, the screws were implanted bilaterally, and the PMMA was allowed to harden for 1 hour. Morphology of PMMA around the screws was observed by section of the vertebrae along the screw. Results Pullout force of pedicle screw fixation in normal vertebrae was (825.5±254.7) N and (1 711.1±488.8)N following augmentation with PMMA. Restoration of a pullout pedicle screw fixation with PMMA was able to salvage pullout force to (1 832.4±497.4) N. The pullout forces following augmentation and restoration were significantly greater than that in normal vertebrae. Morphology of PMMA around the screws was related to the viscosity of PMMA during injection. No PMMA was found in vertebral canal or surface of pedicle. Conclusion Augmentation and restoration with PMMA offered a significantly increase of strength for pedicle screw fixation, and could be used clinically in case of failure of pedicle screw fixation. 目的 評價聚甲基丙烯酸甲酯(polymethylmethacrylate ,PMMA)強化和修復椎弓根螺釘固定的生物力學效果。方法8具成人新鮮腰椎骨L3～5,隨機選擇一側椎弓根放置直徑為6.0mm的CCD(compactCD)椎弓根螺釘 ,另一側以直徑為3.5mm的鉆頭導孔 ,均不穿透椎體前皮質。在材料試驗機上進行椎弓根螺釘拔出實驗 ,拔出速率為5mm/min。然后沿椎弓根孔道注入PMMA粉和水按體積1∶2混合的PMMA強化修復材料3～5ml,雙側椎弓根分別使用與前相同的CCD椎弓根螺釘 ,室溫下1h后再行前述拔出實驗。沿椎弓根螺釘長度方向鋸開標本 ,觀察PMMA在螺釘孔道中的分布范圍。結果CCD椎弓根螺釘在正常椎弓根內的最大拔出力為 (825.5±254.7)N ;在經強化后的正常椎弓根內和在修復失效的椎弓根內 ,CCD椎弓根螺釘最大拔出力分別為 (1711.1±488.8)N和 (1832.4±497.4)N ,高于正常椎弓根螺釘的最大拔出力 ,差異有顯著性意義(P<0.01)。PMMA在螺釘周圍的分布與其注入時的粘稠度有關 ,未見椎管內或椎弓根外有PMMA分布。結論沿椎弓根孔道注入PMMA可顯著增加椎弓根螺釘的拔出力 ,適用于螺釘松動和拔出的修復固

Smoking and health-related quality of life in English general population: Implications for economic evaluations

Copyright @ 2012 Vogl et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This article has been made available through the Brunel Open Access Publishing Fund.Background: Little is known as to how health-related quality of life (HRQoL) when measured by generic instruments such as EQ-5D differ across smokers, ex-smokers and never-smokers in the general population; whether the overall pattern of this difference remain consistent in each domain of HRQoL; and what implications this variation, if any, would have for economic evaluations of tobacco control interventions. Methods: Using the 2006 round of Health Survey for England data (n = 13,241), this paper aims to examine the impact of smoking status on health-related quality of life in English population. Depending upon the nature of the EQ-5D data (i.e. tariff or domains), linear or logistic regression models were fitted to control for biology, clinical conditions, socio-economic background and lifestyle factors that an individual may have regardless of their smoking status. Age- and gender-specific predicted values according to smoking status are offered as the potential 'utility' values to be used in future economic evaluation models. Results: The observed difference of 0.1100 in EQ-5D scores between never-smokers (0.8839) and heavy-smokers (0.7739) reduced to 0.0516 after adjusting for biological, clinical, lifestyle and socioeconomic conditions. Heavy-smokers, when compared with never-smokers, were significantly more likely to report some/severe problems in all five domains - mobility (67%), self-care (70%), usual activity (42%), pain/discomfort (46%) and anxiety/depression (86%) -. 'Utility' values by age and gender for each category of smoking are provided to be used in the future economic evaluations. Conclusion: Smoking is significantly and negatively associated with health-related quality of life in English general population and the magnitude of this association is determined by the number of cigarettes smoked. The varying degree of this association, captured through instruments such as EQ-5D, may need to be fed into the design of future economic evaluations where the intervention being evaluated affects (e.g. tobacco control) or is affected (e.g. treatment for lung cancer) by individual's (or patients') smoking status

Luminescent Organic–Inorganic Hybrids of Functionalized Mesoporous Silica SBA-15 by Thio-Salicylidene Schiff Base

Novel organic–inorganic mesoporous luminescent hybrid material N, N′-bis(salicylidene)-thiocarbohydrazide (BSTC-SBA-15) has been obtained by co-condensation of tetraethyl orthosilicate and the organosilane in the presence of Pluronic P123 surfactant as a template. N,N′-bis(salicylidene)-thiocarbohydrazide (BSTC) grafted to the coupling agent 3-(triethoxysilyl)-propyl isocyanate (TESPIC) was used as the precursor for the preparation of mesoporous materials. In addition, for comparison, SBA-15 doped with organic ligand BSTC was also synthesized, denoted as BSTC/SBA-15. This organic–inorganic hybrid material was well-characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (HRTEM), and photoluminescence spectra, which reveals that they all have high surface area, uniformity in the mesostructure. The resulting materials (BSTC-SBA-15 and BSTC/SBA-15) exhibit regular uniform microstructures, and no phase separation happened for the organic and the inorganic compounds was covalently linked through Si–O bonds via a self-assemble process. Furthermore, the two materials have different luminescence range: BSTC/SBA-15 presents the strong dominant green luminescence, while BSTC-functionalized material BSTC-SBA-15 shows the dominant blue emission

Bilayer manganites: polarons in the midst of a metallic breakdown

The exact nature of the low temperature electronic phase of the manganite materials family, and hence the origin of their colossal magnetoresistant (CMR) effect, is still under heavy debate. By combining new photoemission and tunneling data, we show that in La{2-2x}Sr{1+2x}Mn2O7 the polaronic degrees of freedom win out across the CMR region of the phase diagram. This means that the generic ground state is that of a system in which strong electron-lattice interactions result in vanishing coherent quasi-particle spectral weight at the Fermi level for all locations in k-space. The incoherence of the charge carriers offers a unifying explanation for the anomalous charge-carrier dynamics seen in transport, optics and electron spectroscopic data. The stacking number N is the key factor for true metallic behavior, as an intergrowth-driven breakdown of the polaronic domination to give a metal possessing a traditional Fermi surface is seen in the bilayer system.Comment: 7 pages, 2 figures, includes supplementary informatio

Robust nonfullerene solar cells approaching unity external quantum efficiency enabled by suppression of geminate recombination

Nonfullerene solar cells have increased their efficiencies up to 13%, yet quantum efficiencies are still limited to 80%. Here we report efficient nonfullerene solar cells with quantum efficiencies approaching unity. This is achieved with overlapping absorption bands of donor and acceptor that increases the photon absorption strength in the range from about 570 to 700 nm, thus, almost all incident photons are absorbed in the active layer. The charges generated are found to dissociate with negligible geminate recombination losses resulting in a short-circuit current density of 20 mA cm−2 along with open-circuit voltages >1 V, which is remarkable for a 1.6 eV bandgap system. Most importantly, the unique nano-morphology of the donor:acceptor blend results in a substantially improved stability under illumination. Understanding the efficient charge separation in nonfullerene acceptors can pave the way to robust and recombination-free organic solar cells

Erratum to: Synthesis and Magnetic Properties of Nearly Monodisperse CoFe2O4 Nanoparticles Through a Simple Hydrothermal Condition

<p>Abstract</p> <p>Nearly monodisperse cobalt ferrite (CoFe₂O₄) nanoparticles without any size-selection process have been prepared through an alluring method in an oleylamine/ethanol/water system. Well-defined nanospheres with an average size of 5.5 nm have been synthesized using metal chloride as the law materials and oleic amine as the capping agent, through a general liquid&#8211;solid-solution (LSS) process. Magnetic measurement indicates that the particles exhibit a very high coercivity at 10 K and perform superparamagnetism at room temperature which is further illuminated by ZFC/FC curves. These superparamagnetic cobalt ferrite nanomaterials are considered to have potential application in the fields of biomedicine. The synthesis method is possible to be a general approach for the preparation of other pure binary and ternary compounds.</p

A retrospective observational study on the efficacy of colistin by inhalation as compared to parenteral administration for the treatment of nosocomial pneumonia associated with multidrug-resistant Pseudomonas aeruginosa

<p>Abstract</p> <p>Background</p> <p>Colistin is used as last treatment option for pneumonia associated with multidrug-resistant (MDR) <it>Pseudomonas </it>spp.. Literature about the best administration mode (inhalation versus parenteral treatment) is lacking.</p> <p>Methods</p> <p>A retrospective study of 20 intensive care patients with a pneumonia associated with MDR <it>P. aeruginosa </it>receiving colistin sulphomethate sodium (Colistineb^®) between 2007 and 2009 was performed. A strain was considered multidrug-resistant if it was resistant to at least 6 of the following antibiotics: piperacillin-tazobactam, ceftazidime, cefepime, meropenem, aztreonam, ciprofloxacin, and amikacin. The administration mode, predicted mortality based on the SAPS3 score, SOFA score at onset of the colistin treatment, clinical and microbiological response, and mortality during the episode of the infection were analysed. The non parametric Kruskal-Wallis and Fisher's Exact test were used for statistical analysis of respectively the predicted mortality/SOFA score and mortality rate.</p> <p>Results</p> <p>Six patients received colistin by inhalation only, 5 were treated only parenterally, and 9 by a combination of both administration modes. All patients received concomitant beta-lactam therapy. The mean predicted mortalities were respectively 72%, 68%, and 69% (p = 0.91). SOFA scores at the onset of the treatment were also comparable (p = 0.87). Clinical response was favorable in all patients receiving colistin by inhalation (6/6) and in 40% (2/5) of the patients receiving colistin parenterally (p = 0.06). In the patients with colistin administered both via inhalation and parenterally, clinical response was favorable in 78% of the patients (7/9) (p = 0.27 as compared to the treatment group receiving colistin only parenterally). When all patients with inhalation therapy were compared to the group without inhalation therapy, a favorable clinical response was present in respectively 87% and 40% (p = 0.06). In none of the patients, the <it>Pseudomonas </it>spp. was eradicated from the follow-up cultures.</p> <p>All patients in the parenterally treated group died. None of the patients receiving colistin by inhalation, and 3 of 9 patients of the combination group eventually died (p = 0.002 and p = 0.03 respectively as compared to the group receiving colistin only parenterally).</p> <p>Conclusions</p> <p>Aerosolized colistin could be beneficial as adjunctive treatment for the management of pneumonia due to MDR <it>P. aeruginosa</it>.</p

Sparing effects of selenium and ascorbic acid on vitamin C and E in guinea pig tissues

BACKGROUND: Selenium (Se), vitamin C and vitamin E function as antioxidants within the body. In this study, we investigated the effects of reduced dietary Se and L-ascorbic acid (AA) on vitamin C and α-tocopherol (AT) status in guinea pig tissues. METHODS: Male Hartley guinea pigs were orally dosed with a marginal amount of AA and fed a diet deficient (Se-D/MC), marginal (Se-M/MC) or normal (Se-N/MC) in Se. An additional diet group (Se-N/NC) was fed normal Se and dosed with a normal amount of AA. Guinea pigs were killed after 5 or 12 weeks on the experimental diets at 24 and 48 hours post AA dosing. RESULTS: Liver Se-dependent glutathione peroxidase activity was decreased (P < 0.05) in guinea pigs fed Se or AA restricted diets. Plasma total glutathione concentrations were unaffected (P > 0.05) by reduction in dietary Se or AA. All tissues examined showed a decrease (P < 0.05) in AA content in Se-N/MC compared to Se-N/NC guinea pigs. Kidney, testis, muscle and spleen showed a decreasing trend (P < 0.05) in AA content with decreasing Se in the diet. Dehydroascorbic acid concentrations were decreased (P < 0.05) in several tissues with reduction in dietary Se (heart and spleen) or AA (liver, heart, kidney, muscle and spleen). At week 12, combined dietary restriction of Se and AA decreased AT concentrations in most tissues. In addition, restriction of Se (liver, heart and spleen) and AA (liver, kidney and spleen) separately also reduced AT in tissues. CONCLUSION: Together, these data demonstrate sparing effects of Se and AA on vitamin C and AT in guinea pig tissues