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101.
Sotirios G. Zarogiannis Aristotelis S. Filippidis Solana Fernandez Asta Jurkuvenaite Namasivayam Ambalavanan Andrei Stanishevsky Yogesh K. Vohra Sadis Matalon 《Respiratory physiology & neurobiology》2013,185(2):454-460
Titanium dioxide engineered nanoparticles (nano-TiO2) are widely used in the manufacturing of a number of products. Due to their size (<100 nm), when inhaled they may be deposited in the distal lung regions and damage Clara cells. We investigated the mechanisms by which short-term (1-h) incubation of human airway Clara-like (H441) cells to nano-TiO2 (6 nm in diameter) alters the ability of H441 cells to adhere to extracellular matrix. Our results show that 1 h post-incubation, there was a 3-fold increase of extracellular H2O2, increased intracellular oxidative stress as demonstrated by 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) oxidation, and a 5-fold increase of phosphor-ERK1/2 as measured by Western blotting. These changes were accompanied by a 25% decrease of H441 adherence to fibronectin (p < 0.05 compared to vehicle incubated H441 cells). Pretreatment with the ERK1/2 inhibitor U0126 for 3 h, partially prevented this effect. In conclusion, short-term exposure of H441 cells to nano-TiO2 appears to reduce adherence to fibronectin due to oxidative stress and activation of ERK1/2. 相似文献
102.
103.
仲伟军 《中国医院建筑与装备》2012,13(10):100-101
医院污水中不同程度地含有多种病毒、病菌、寄生虫卵和其他一些消毒剂、有机溶剂、酸、碱以及放射性等有毒有害物质。加强对医院产生的污水的控制和管理、提高医院污水处理的消毒效果是利国利民的事情,文中针对张家港市第一人民医院的新建工程,具体阐述了污水处理系统使用中的体会。 相似文献
104.
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106.
T. Stober J. L. Bermejo F. S. Schwindling M. Schmitter 《Journal of oral rehabilitation》2016,43(8):621-629
The purpose of this study was to measure enamel wear caused by antagonistic monolithic zirconia crowns and to compare this with enamel wear caused by contralateral natural antagonists. Twenty monolithic zirconia full molar crowns were placed in 20 patients. Patients with high activity of the masseter muscle at night (bruxism) were excluded. For analysis of wear, vinylpolysiloxane impressions were prepared after crown incorporation and at 6‐, 12‐, and 24‐month follow‐up. Wear of the occlusal contact areas of the crowns, of their natural antagonists, and of two contralateral natural antagonists (control teeth) was measured by use of plaster replicas and a 3D laser‐scanning device. Differences of wear between the zirconia crown antagonists and the control teeth were investigated by means of two‐sided paired Student's t‐tests and linear regression analysis. After 2 years, mean vertical loss was 46 μm for enamel opposed to zirconia, 19–26 μm for contralateral control teeth and 14 μm for zirconia crowns. Maximum vertical loss was 151 μm for enamel opposed to zirconia, 75–115 μm for control teeth and 60 μm for zirconia crowns. Statistical analysis revealed significant differences between wear of enamel by zirconia‐opposed teeth and by control teeth. Gender, which significantly affected wear, was identified as a possible confounder. Monolithic zirconia crowns generated more wear of opposed enamel than did natural teeth. Because of the greater wear caused by other dental ceramics, the use of monolithic zirconia crowns may be justified. 相似文献
107.
Orlando Oliveira de Morais érica Freitas Lima Lemos Márcia Carolline dos Santos Sousa Ciro Martins Gomes Izelda Maria Carvalho Costa Carmen Déa Ribeiro de Paula 《Anais brasileiros de dermatologia》2013,88(2):238-242
Melasma represents a pigmentary disorder that is difficult to treat. This study aims
to broadly review the use of ablative lasers (Er:YAG and CO2) in the treatment of
melasma, presenting the level of evidence of studies published to date. A total of 75
patients were enrolled in four case series studies (n=39), one controlled clinical
trial (n=6) and one randomized controlled clinical trial (n=30). Studies on the
Er:YAG laser showed better results with the use of short square-shaped pulses, which
determined low rates of post-inflammatory hyperpigmentation and long-lasting
maintenance of results. Likewise, studies on the CO2 laser proved the benefits of
short pulse duration along with low-density energy. Post-treatment maintenance with
the use of antipigmenting creams was necessary and effective to sustain long-term
results. Ablative lasers may represent another useful and effective tool against
melasma. Postinflammatory hyperpigmentation and difficulty in sustaining long-term
results still represent the main limitations to a broader use of ablative lasers.
Based on actual evidence, the use of this technology should be restricted to patients
with recalcitrant disease. Further studies will help establish optimal laser
parameters and treatment regimens. 相似文献
108.
Influence of Oxynitrided Surface in the Production of a Less Susceptible Titanium Surface to Skin‐Borne Bacterial Adhesion
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Michelle de Medeiros Aires Janine Treter Danilo Cavalcante Braz Cristiano Krug Alexandre José Macedo Clodomiro Alves Júnior 《Artificial organs》2016,40(5):521-526
There is a growing quest for an ideal biomaterial that shows appropriate cellular response and is not susceptible to microbial adhesion. In this study, commercial grade II titanium was submitted to RF/DC plasma surface modification at 2.2 mbar, using gas mixtures of argon, nitrogen, and oxygen at proportions 4:1:2 and 4:1:3. The surfaces were physically and chemically characterized. In order to evaluate bacterial response, the surfaces were exposed to Staphylococcus epidermidis. Oxynitrided samples, although having a higher roughness as compared with untreated samples, exhibited lower bacterial growth. This observation is probably due to the formation of different crystalline phases of nitrides and oxides caused by plasma treatment. The surface with highest contact angle and highest surface tension showed lower bacterial adhesion. These results were confirmed by scanning electron microscopy. The role of nitrogen in reducing bacterial adhesion is clear when this material is compared with untreated titanium, on which only an oxide film is present. 相似文献
109.
Large efforts are invested on the development of in vitro tests to evaluate nanomaterial (NM) toxicity. In order to assess the relevance of the adverse effects identified in in vitro toxicity tests a thorough understanding of the biokinetics of NMs is critical. We used different in vitro and in vivo test methods to evaluate cell uptake and oral absorption of titanium dioxide nanoparticles (TiO2 NPs). These NPs were readily uptaken by A549 cells (carcinomic human alveolar basal epithelial cells) in vitro. Such rapid uptake contrasted with a very low oral absorption in a differentiated Caco-2 monolayer system (human epithelial colorectal adenocarcinoma cells) and after oral gavage administration to rats. In this oral study, no significant increase in the levels of titanium was recorded by ICP-MS in any of the tissues evaluated (including among other: small intestine, Peyer's patches, mesenteric lymph nodes, liver, and spleen). No NPs were observed by TEM in sections of the small intestine, except for several particles in the cytoplasm of a cell from a Peyer's Patch area. The observation of NPs in Peyer's Patch suggests that the Caco-2 monolayer system is likely to underestimate the potential for oral absorption of NPs and that the model could be improved by including M-cells in co-culture. 相似文献
110.
本文介绍了测定二氧化碳结合力的一种新型仪器一快速无水银二氧化碳结合力测定器。该测定器安全无污染,测定结果准确,具有一定的科学创新性和实用性。 相似文献