916 resultados para Expanded austenite
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Includes bibliography
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Neuromyelitis optica (NMO) has been traditionally described as the association of recurrent or bilateral optic neuritis and longitudinally extensive transverse myelitis (LETM). Identification of aquaporin-4 antibody (AQP4-IgG) has deeply changed the concept of NMO. A spectrum of NMO disorders (NMOSD) has been formulated comprising conditions which include both AQP4-IgG seropositivity and one of the index events of the disease (recurrent or bilateral optic neuritis and LETM). Most NMO patients harbor asymptomatic brain MRI lesions, some of them considered as typical of NMO. Some patients with aquaporin-4 autoimmunity present brainstem, hypothalamic or encephalopathy symptoms either preceding an index event or occurring isolatedly with no evidence of optic nerve or spinal involvement. On the opposite way, other patients have optic neuritis or LETM in association with typical lesions of NMO on brain MRI and yet are AQP4-IgG seronegative. An expanded spectrum of NMO disorders is proposed to include these cases.
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This study evaluated linear alkylbenzene sulfonate removal in an expanded granular sludge bed reactor with hydraulic retention times of 26 h and 32 h. Sludge bed and separator phase biomass were phylogenetically characterized (sequencing 16S rRNA) and quantified (most probable number) to determine the total anaerobic bacteria and methanogenic Archaea. The reactor was fed with a mineral medium supplemented with 14 mg l(-1) LAS, ethanol and methanol. The stage I-32 h consisted of biomass adaptation (without LAS influent) until reactor stability was achieved (COD removal >97%). In stage II-32 h, LAS removal was 74% due to factors such as dilution, degradation and adsorption. Higher HRT values increased the LAS removal (stage III: 26 h - 48% and stage IV: 32 h - 64%), probably due to increased contact time between the biomass and LAS. The clone libraries were different between samples from the sludge bed (Synergitetes and Proteobacteria) and the separator phase (Firmicutes and Proteobacteria) biomass. (C) 2011 Elsevier Ltd. All rights reserved.
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CONTEXT: Orthotopic liver transplantation is an excellent treatment approach for hepatocellular carcinoma in well-selected candidates. Nowadays some institutions tend to Expand the Milan Criteria including tumor with more than 5 cm and also associate with multiple tumors none larger than 3 cm in order to benefit more patients with the orthotopic liver transplantation. METHODS: The data collected were based on the online database PubMED. The key words applied on the search were "expanded Milan criteria" limited to the period from 2000 to 2009. We excluded 19 papers due to: irrelevance of the subject, lack of information and incompatibility of the language (English only). We compiled patient survival and tumor recurrence free rate from 1 to 5-years in patients with hepatocellular carcinoma submitted to orthotopic liver transplantation according to expanded the Milan criteria from different centers. RESULTS: Review compiled data from 23 articles. Fourteen different criteria were found and they are also described in detail, however the University of California - San Francisco was the most studied one among them. CONCLUSION: Expanded the Milan criteria is a useful attempt for widening the preexistent protocol for patients with hepatocellular carcinoma in waiting-list for orthotopic liver transplantation. However there is no significant difference in patient survival rate and tumor recurrence free rate from those patients that followed the Milan criteria.
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Neuromyelitis optica (NMO) has been traditionally described as the association of recurrent or bilateral optic neuritis and longitudinally extensive transverse myelitis (LETM). Identification of aquaporin-4 antibody (AQP4-IgG) has deeply changed the concept of NMO. A spectrum of NMO disorders (NMOSD) has been formulated comprising conditions which include both AQP4-IgG seropositivity and one of the index events of the disease (recurrent or bilateral optic neuritis and LETM). Most NMO patients harbor asymptomatic brain MRI lesions, some of them considered as typical of NMO. Some patients with aquaporin-4 autoimmunity present brainstem, hypothalamic or encephalopathy symptoms either preceding an index event or occurring isolatedly with no evidence of optic nerve or spinal involvement. On the opposite way, other patients have optic neuritis or LETM in association with typical lesions of NMO on brain MRI and yet are AQP4-IgG seronegative. An expanded spectrum of NMO disorders is proposed to include these cases.
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High serum levels of Interleukin-6 (IL-6) correlate with poor outcome in breast cancer patients. However no data are available on the relationship between IL-6 and stem/progenitor cells which may fuel the genesis of breast cancer in vivo. Herein, we address this issue in mammospheres (MS), multi-cellular structures enriched in stem/progenitor cells of the mammary gland, and also in MCF-7 breast cancer cells. We show that MS from node invasive breast carcinoma tissues express IL-6 mRNA at higher levels than MS from matched non-neoplastic mammary glands. We find that IL-6 mRNA is detectable only in basal-like breast carcinoma tissues, an aggressive variant showing stem cell features. Our results reveal that IL-6 triggers a Notch-3-dependent up-regulation of the Notch ligand Jagged-1, whose interaction with Notch-3 promotes the growth of MS and MCF-7 derived spheroids. Moreover, IL-6 induces a Notch-3-dependent up-regulation of the carbonic anhydrase IX gene, which promotes a hypoxia-resistant/invasive phenotype in MCF-7 cells and MS. Finally, an autocrine IL-6 loop relies upon Notch-3 activity to sustain the aggressive features of MCF-7-derived hypoxia-selected cells. In conclusion, our data support the hypothesis that IL-6 induces malignant features in Notch-3 expressing, stem/progenitor cells from human ductal breast carcinoma and normal mammary gland.
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Zusammenfassung:rnDie vorliegende Arbeit beschreibt das Design und die Synthese neuartiger Porphyrinoide anhand der Modifikation und der π-Systemausdehnung an der Peripherie des Porphyrin-Gerüsts. Die Darstellung künstlicher Porphyrine ist von Interesse, da neue physiko-chemischen Eigenschaften erhalten und untersucht werden können. Die in dieser Arbeit vorgestellten Porphyrinoide wurden mit Hilfe von modernen Synthesemethoden wie den metallkatalysierten Kreuzkupplungen und somit durch Aryl-Aryl Verknüpfungen aufgebaut.rnDer erste Teil dieser Arbeit befasst sich mit der Modifikation des Porphyrin-Gerüsts. Porphyrine bestehen aus jeweils zwei Pyrrol- und Pyrrolenin-Einheiten, welche systematisch ausgetauscht wurden. Die Pyrrol-Einheiten wurden durch Carbazol ersetzt, das sich formal vom Pyrrol durch Anfügen von zwei Benzogruppen ableitet und deshalb besonders gut geeignet ist. Die Pyrrolenin-Einheiten wurden aus folgenden Gründen durch andere Heterozyklen wie Pyridin, Pyrrol oder Triazol ersetzt: rn* Nachbildung des stabilen Porphyrin trans-NH-Tautomers (Carbazol und Pyridin)rn* Nachbildung von (NH)4-Liganden wie Calix[4]pyrrol (Carbazol und Pyrrol)rn* Vereinigung von N-H und C-H Wasserstoffbrücken-Donor-Einheiten in einem Makrozyklus (Carbazol und Triazol)rnDie Synthese eines drei-Zentren Porphyrinoids mit ausgedehntem π-System wird im zweiten Teil der vorliegenden Arbeit beschrieben. Dieses Thema basiert auf der aktuellen Entwicklung von nicht-Edelmetall basierten Katalysatoren für die Reduktion von Sauerstoff. Hier werden derzeit N4 makrozyklische Metallkomplexe, die mehrere katalytisch aktive Stellen aufweisen, untersucht. In diesem Zusammenhang, hat die Gruppe von Prof. Müllen einen neuartigen drei-Zentren-Komplex entwickelt. Ausgehend von diesen Erkenntnissen, dient diese Arbeit zur Verbesserung der katalytischen Aktivität des drei-Zentren-Komplex durch die Variation von verschieden Substituenten. Hierbei wurden zwei wesentliche Konzepte verfolgt:rn* Vernetzung durch die Bildung von Netzwerken oder durch Pyrolyse in der Mesophasern* Verbesserung des Katalysator-Trägermaterial-KontaktsrnNeben den Synthesen wurden die Eigenschaften und möglichen Anwendungen dieser neuartigen Materialen untersucht, wie z.B. als Liganden für Übergangsmetalle, als Anionenrezeptoren oder als Elektrokatalysatoren für die Reduktion von Sauerstoff. rn
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Herein, we report a technically simple method for isolation and culture of human follicular melanocytes based on explant cultures of epilated hair follicles. This technique does not require any surgical intervention and allows the isolation and cultivation of follicular melanocytes from a comparatively small amount of raw material. Generally, 30-60 human anagen hair follicles have been plucked from the scalp of healthy donors and cultivated under low oxygen pressure (5%). After a short period of time cells of various types were growing out from the outer root sheath (ORS) of the hair follicles. Under the selected culture conditions, most of the cells other than melanocytes have been eliminated and a nearly 100% pure population of melanocytes has been achieved, as confirmed by immunohistochemical analyses for melanocyte-specific markers, for example, Tyrosinase-1, S-100 and premelanosomal antigens. These melanocytes derived from the ORS were proliferating for up to 2 months.
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The aim of this study was to investigate the interconnection between the processes of proliferation, dedifferentiation, and intrinsic redifferentiation (chondrogenic) capacities of human articular chondrocyte (HAC), and to identify markers linking HAC dedifferentiation status with their chondrogenic potential. Cumulative population doublings (PD) of HAC expanded in monolayer culture were determined, and a threshold range of 3.57-4.19 PD was identified as indicative of HAC loss of intrinsic chondrogenic capacity in pellets incubated without added chondrogenic factors. While several specific gene and surface markers defined early HAC dedifferentiation process, no clear correlation with the loss of intrinsic chondrogenic potential could be established. CD90 expression during HAC monolayer culture revealed two subpopulations, with sorted CD90-negative cells showing lower proliferative capacity and higher chondrogenic potential compared to CD90-positive cells. Although these data further validated PD as critical for in vitro chondrogenesis, due to the early shift in expression, CD90 could not be considered for predicting chondrogenic potential of HAC expanded for several weeks. In contrast, an excellent mathematically modeled correlation was established between PD and the decline of HAC expressing the intracellular marker S100, providing a direct link between the number of cell divisions and dedifferentiation/loss of intrinsic chondrogenic capacity. Based on the dynamics of S100-positive HAC during expansion, we propose asymmetric cell division as a potential mechanism of HAC dedifferentiation, and S100 as a marker to assess chondrogenicity of HAC during expansion, of potential value for cell-based cartilage repair treatments.
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Incorporation of enediynes into anticancer drugs remains an intriguing yet elusive strategy for the design of therapeutically active agents. Density functional theory was used to locate reactants, products, and transition states along the Bergman cyclization pathways connecting enediynes to reactive para-biradicals. Sum method correction to low-level calculations confirmed B3LYP/6-31G(d,p) as the method of choice in investigating enediynes. Herein described as MI:Sum, calculated reaction enthalpies differed from experiment by an average of 2.1 kcal·mol−1 (mean unsigned error). A combination of strain energy released across the reaction coordinate and the critical intramolecular distance between reacting diynes explains reactivity differences. Where experimental and calculated barrier heights are in disagreement, higher level multireference treatment of the enediynes confirms lower level estimates. Previous work concerning the chemically reactive fragment of esperamcin, MTC, is expanded to our model system MTC2.
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Allograft acceptance and tolerance can be achieved by different approaches including inhibition of effector T cell responses through CD28-dependent costimulatory blockade and induction of peripheral regulatory T cells (Tregs). The observation that Tregs rely upon CD28-dependent signals for development and peripheral expansion, raises the intriguing possibility of a counterproductive consequence of CTLA4-Ig administration on tolerance induction. We have investigated the possible negative effect of CTLA4-Ig on Treg-mediated tolerance induction using a mouse model of single MHC class II-mismatched skin grafts in which long-term acceptance was achieved by short-term administration of IL-2/anti-IL-2 complex. CTLA4-Ig treatment was found to abolish Treg-dependent acceptance in this model, restoring skin allograft rejection and Th1 alloreactivity. CTLA4-Ig inhibited IL-2-driven Treg expansion, and prevented in particular the occurrence of ICOS(+) Tregs endowed with potent suppressive capacities. Restoring CD28 signaling was sufficient to counteract the deleterious effect of CTLA4-Ig on Treg expansion and functionality, in keeping with the hypothesis that costimulatory blockade inhibits Treg expansion and function by limiting the delivery of essential CD28-dependent signals. Inhibition of regulatory T cell function should therefore be taken into account when designing tolerance protocols based on costimulatory blockade. Copyright 2012 The American Society of Transplantation and the American Society of Transplant Surgeons