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排序方式: 共有238条查询结果,搜索用时 15 毫秒
31.
Investigating heavy metal resistance, bioaccumulation and metabolic profile of a metallophile microbial consortium native to an abandoned mine 总被引:1,自引:0,他引:1
Sprocati AR Alisi C Segre L Tasso F Galletti M Cremisini C 《The Science of the total environment》2006,366(2-3):649-658
Contaminated sites represent new ecological niches where historical pollution has originated an unusual microbial biodiversity. The knowledge of these microorganisms contributes to the discovery of new pathways and metabolic networks and may offer potential solutions for damaged areas. In the present work seven microbial consortia have been isolated from an abandoned mine of blend and galena (Ingurtosu, Italy) through a selection for resistance to zinc (tested up to 40 mM in solution). All the consortia were able to accumulate zinc and the best accumulator, named Ing5, has been studied for the following characteristics: resistance and accumulation of Zn, Cd, Hg, bioaccumulation mechanisms of Zn, and influence of Zn and Cd on the metabolic profile. The results indicate that the consortium Ing5 bears resistance systems for Cd and Hg as well as Zn and that, for some of the 5 isolates belonging to Ing5, the resistance thresholds are higher in consortium than in pure culture. The prevalent mechanism for zinc accumulation can be reasonably considered to be metabolism-dependent, inducible and regulated by metal concentrations. The study on the metabolic profile, carried out by the Biolog system, shows that Zn exerts a very low influence on the metabolic profile and that this influence can also be positive; Cd has a stronger negative influence but that, despite this, the consortium is able to maintain a wide metabolic potential in the presence of heavy metals. These features of Ing5 make it a good candidate for biotechnological applications and for further investigation of the degradation of organic pollutants in the presence of metals. 相似文献
32.
目的探讨单发肿块型肺部炎性假瘤(IPT)的CT影像学特征。方法收集术后经病理及纤维镜活检证实的37例IPT患者的临床及CT资料,对其CT表现进行回顾性分析。结果①病灶位于肺的外围25例,其中宽基底伴邻近胸膜肥厚23例。②病灶形态不一(球形9例,方形或楔形14例,不规则形14例),特征性表现(刀切征13例,桃尖征11例)。③密度不均匀26例,周围淡薄渗出35例,空气支气管征14例,血管纠集增粗,血管穿行于病灶之中,但未见中断14例;增强明显均匀持续强化12例。结论 IPT影像学表现多样,全面分析,综合CT影像新技术,有助于提高本病诊断的准确性。 相似文献
33.
Photonic crystals are ordered nanostructures that are designed to manipulate the propagation of light. The periodicity of a photonic crystal can be engineered to be highly reflective at selected wavelengths. In this work, a mono-layer and double-layer colloidal photonic crystal film were self-assembled on a glass substrate to be used as backreflectors in a dye-sensitized solar cell (DSSC). The colloidal photonic crystal film consists of different polystyrene monodispersed particles with sizes between 200 nm and 290 nm. Making use of flow controlled vertical deposition (FCVD) method, opaline films of Bragg's reflection wavelength between 450 nm to 750 nm were achieved. These wavelengths were designed to match the absorption spectrum of the Ruthenium-complex dye used in DSSC. An enhancement in incident photon-to-current conversion efficiency (IPCE) of the opaline backreflector DSSC of about 30% at Bragg's peak wavelength has been achieved. 相似文献
34.
Susana Díaz‐Amaya Min Zhao Li‐Kai Lin Carlos Ostos Jan P. Allebach George T.‐C. Chiu Amanda J. Deering Lia A. Stanciu 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(24)
The increasing incidence of infectious outbreaks from contaminated food and water supply continues imposing a global burden for food safety, creating a market demand for on‐site, disposable, easy‐to‐use, and cost‐efficient devices. Despite of the rapid growth of biosensors field and the generation of breakthrough technologies, more than 80% of the platforms developed at lab‐scale never will get to meet the market. This work aims to provide a cost‐efficient, reliable, and repeatable approach for the detection of foodborne pathogens in real samples. For the first time an optimized inkjet printing platform is proposed taking advantage of a carefully controlled nanopatterning of novel carboxyl‐functionalized aptameric ink on a nitrocellulose substrate for the highly efficient detection of E. coli O157:H7 (25 colony forming units (CFU) mL?1 in pure culture and 233 CFU mL?1 in ground beef) demonstrating the ability to control the variation within ±1 SD for at least 75% of the data collected even at very low concentrations. From the best of the knowledge this work reports the lowest limit of detection of the state of the art for paper‐based optical detection of E. coli O157:H7, with enough evidence (p > 0.05) to prove its high specificity at genus, species, strain, and serotype level. 相似文献
35.
36.
Assaf Gal Vlad Brumfeld Steve Weiner Lia Addadi Dan Oron 《Advanced materials (Deerfield Beach, Fla.)》2012,24(10):OP77-OP83
Cystoliths are amorphous calcium carbonate bodies that form in the leaves of some plant families. Cystoliths are regularly distributed in the epidermis and protrude into the photosynthetic tissue, the mesophyll. The photosynthetic pigments generate a steep light gradient in the leaf. Under most illumination regimes the outer mesophyll is light saturated, thus the photosynthetic apparatus is kinetically unable to use the excess light for photochemistry. Here we use micro‐scale modulated fluorometry to demonstrate that light scattered by the cystoliths is distributed from the photosynthetically inefficient upper tissue to the efficient, but light deprived, lower tissue. The results prove that the presence of light scatterers reduces the steep light gradient, thus enabling the leaf to use the incoming light flux more efficiently. MicroCT and electron microscopy confirm that the spatial distribution of the minerals is compatible with their optical function. During the study we encountered large calcium oxalate druses in the same anatomical location as the cystoliths. These druses proved to have similar light scattering functions as the cystoliths. This study shows that certain minerals in the leaves of different plants distribute the light flux more evenly inside the leaf. 相似文献
37.
G Gourdon P Dessen AS Lia C Junien H Hofmann-Radvanyi 《Canadian Metallurgical Quarterly》1997,40(2):73-77
The ultrastructural morphology of the interface region between the stria vascularis (SV) and spiral ligament (SL) was examined in the neonatal rat cochlea via transmission electron microscopy. At postnatal day (PND) 3, morphology of both basal cells and fibrocytes was simple and immature. Only a small number of fibrocytes was observed in the SL. Intercellular junctions between basal cells and fibrocytes, and between adjacent fibrocytes, were few. At PND 7, the number of fibrocytes increased, and more organelles appeared within their cytoplasm. From PND 11 to 14, nuclei of the basal cells appeared to be more spindle-shaped and contained more heterochromatin. The cytoplasm of the fibrocytes was pale, and a greater number of cytoplasmic vesicles and mitochondria emerged. More intercellular junctions were observed between basal cells and fibrocytes at the interface region and between fibrocytes in the SL. By PND 21, the morphology of basal cells and fibrocytes and their intercellular junctions appeared to be adult-like. These morphological observations correlate with previous reports on the functional maturation of the developing rat cochlea. 相似文献
38.
钢铁行业的轧钢加热炉大量采用重油作为燃料;另一方面各企业均不同程度地存在高炉煤气的大量放散。本文通过低热值纯高炉煤气在广钢股份公司高速线材轧钢厂步进式加热炉成功使用的首个例子,说明钢铁企业可以较好地利用高炉煤气,进行余能回收,以大幅提高企业的经济效益。 相似文献
39.
Felice Strollo Lia Pecorelli Giovanna Strollo Massimo Morè Giuseppe Riondino Maria Angela Masini Bianca Maria Uva 《Microgravity science and technology》2006,18(3-4):226-229
A significant reversible decrease in testosterone (T) has been associated with microgravity in male rodents and humans. Urinary T excretion increases in primates under hypergravity. Hypogonadism is somehow related to abnormally high levels of leptin (L), a hormone produced by the adipose tissue which has been found to increase under microgravity simulation conditions like head down bed rest (HDBR). The aim of this study was to assess hemodynamic and pituitary-adrenal and -gonadal adaptation to an acute HDBR test to be eventually used on a routine basis to get better prepared to next space flights. The Authors performed a 1 hour ?12° HDBR in 6 male and 6 female volunteers who underwent heart rate and blood pressure measurement together with a blood draw three times at 30 min intervals from the start to the end of the test for L, T, estradiol (E2), LH, androstenedione (A), cortisol (F), ACTH. 12 age- and sexmatched control subjects followed the same protocol except for keeping the sitting position all the time. According to the ANOVA for repeated measures, no changes occurred in L, T, E2 or LH whereas A, F and ACTH significantly decreased independently of gender. During HDBR systolic blood pressure decreased in both genders, diastolic blood pressure decreased significantly only in men and HR showed a more clear-cut decrease in women than in men. As a conclusion, such an acute steep-slope HDBR protocol may be efficiently used to testing immediate individual haemodynamic or adrenal response to microgravity but is not suitable for studies concerning gonadal adaptation. 相似文献
40.
Supramolecular organized multilayers composed of glucose oxidase (GOx) and osmium-derivatized poly(allylamine) redox polymer have been self-assembled electrostatically from Os-polyelectrolyte solutions of variable pH (5.5-8.8) leading to a decrease of the linear charge density in the PAH-Os with increasing pH. The layer-by-layer enzyme multilayers were studied by ellipsometry, quartz crystal microbalance, AFM, cyclic voltammetry, and electrocatalytic oxidation of beta-D-glucose. At higher adsorption solution pH, an increase in the film thickness, enzyme loading, and redox charge was observed. While the electrocatalytic response increases with the increase of the adsorption solution pH (decrease of the polyelectrolyte linear charge), the FADH2 oxidation bimolecular rate constant has a maximum in the pH range 7.0-7.5 where a change in the film growth mechanism is observed. 相似文献