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51.
Germ-line mutations in the RET proto-oncogene are associated with multiple endocrine neoplasia type 2A (MEN 2A) and with familial medullary thyroid carcinoma (FMTC). Detection of these mutations allows the identification of the affected kindred members, who will develop medullary thyroid carcinoma (MTC) in 100% of cases. We studied 24 patients of two kindreds (MEN 2A and FMTC). Basal calcitonin levels and pentagastrin-stimulated calcitonin were measured in all patients. The RET mutations were detected by DNA analysis. The RET mutations were identified in 14 patients. Two of them had been operated in the past, 2 refused operation and 4 were living abroad. In the 6 remaining, only one showed a thyroid mass, basal calcitonin was normal in all patients except one, and pentagastrin-stimulated calcitonin was negative in 2 patients. Total thyroidectomy was performed in all cases. Histology showed C-cell hyperplasia in all patients and MTC in 5 of them. In MEN 2A and FMTC DNA analysis allows the identification of RET mutation carriers, in which presymptomatic thyroidectomy allows and improvement in survival.  相似文献   
52.
Modern construction has been characterized as a complex and fragmented process. These characteristics have produced a decrease in the quality and cost efficiency of projects. It has been proven that this problem can be partially overcome by implementing constructability, which is based on the integration of construction knowledge into design (as was done in the past). The implementation of constructability is not easy because it represents a change in the way things have been done in the last century. Prior research has found a lack of constructability efforts among participants in the construction industry, especially general contractors. Because builders can play an important role in implementing constructability, this paper assesses constructability practices among general contractors. The data were obtained from a mailed survey. It was found that contractors applied constructability concepts and participated during the earliest phase of the projects more often than is thought. In addition, the findings showed that constructability practices differed depending on the characteristics of the organization, the type of work performed, and the type of contractual arrangement.  相似文献   
53.
Growing economies have the dual challenge of economical and industrial growing, but in a sustainable way and with protection of Ecosystems, all prior requirements are a must that are either satisfied or Human Kind will suffer the irreparable loss of Earth Biosphere. Prospective studies show that for the period 1990–2010 the petroleum will be heavier and richer in sulphur. In order to make a more sustainable use of Mexican heavy petroleum the actual “Life Cycle” of Mexican Bottom of Barrel crude oil can be modified through the proposal of producing an activated carbon (CAFOB) from Mexican petroleum vacuums residue and Mexican petroleum coke applied in the flue gases desulphuration, therefore, experimental activated carbon was made from Mexican petroleum vacuums residue and petroleum coke and desulphuration adsorption tests of a synthetic flue gas mixture similar in composition to flue gases produced from the burning of Mexican heavy fuel oil were made. Commercial activated carbons were used as reference materials. The CAFOB180M experimental activated carbon showed a good desulphuration capacity compared to commercial activated carbon, showing its potentiality in the process of evolving the actual “Life Cycle” of Mexican Bottom of Barrel crude oil to a more sustainable one.  相似文献   
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Under COH2O systems at initial pH values s> 12.6, an Illinois No. 6 coal, PSOC-26, was converted to a fully pyridine-soluble product, with benzene and hexane solubilities of 50% and 18%, respectively. The product gases were H2 and CO2. However, the expected H2CO2 ratio of 1.0 based on the water gas shift reaction was not observed, but the deficit in hydrogen was found in the increased hydrogen content of the coal product. 95% coal carbon recovery and good hydrogen balances were obtained, and the coal products were found to be very similar to those from conventional tetralin systems. The results suggest an efficient base-catalysed process, and that COH2O systems are useful for coal studies.  相似文献   
56.
Asthma is one of the most common respiratory disease that affects both children and adults worldwide, with diverse phenotypes and underlying pathogenetic mechanisms poorly understood. As technology in genome sequencing progressed, scientific efforts were made to explain and predict asthma’s complexity and heterogeneity, and genome-wide association studies (GWAS) quickly became the preferred study method. Several gene markers and loci associated with asthma susceptibility, atopic and childhood-onset asthma were identified during the last few decades. Markers near the ORMDL3/GSDMB genes were associated with childhood-onset asthma, interleukin (IL)33 and IL1RL1 SNPs were associated with atopic asthma, and the Thymic Stromal Lymphopoietin (TSLP) gene was identified as protective against the risk to TH2-asthma. The latest efforts and advances in identifying and decoding asthma susceptibility are focused on epigenetics, heritable characteristics that affect gene expression without altering DNA sequence, with DNA methylation being the most described mechanism. Other less studied epigenetic mechanisms include histone modifications and alterations of miR expression. Recent findings suggest that the DNA methylation pattern is tissue and cell-specific. Several studies attempt to describe DNA methylation of different types of cells and tissues of asthmatic patients that regulate airway remodeling, phagocytosis, and other lung functions in asthma. In this review, we attempt to briefly present the latest advancements in the field of genetics and mainly epigenetics concerning asthma susceptibility.  相似文献   
57.
Magnetic resonance imaging (MRI) and scanning microbeam nuclear reaction analysis (NRA) were used to monitor changes of water ingress into polyglycolide (PGA) disks with degradation time. MRI detects H2O, whereas NRA is sensitive to D2O. The acid-catalysed hydrolysis of the ester is significantly slower in D2O than H2O because of the kinetic isotope effect. This behaviour was investigated in Part I. In this paper, NRA was used to investigate PGA hydration in buffers made from D2O, and NRA and MRI experiments were performed on samples degraded buffers made from a 50% mixture of D2O and H2O (D2O/H2O 50:50) to allow a comparison between the two techniques. The NRA and MRI results provide direct evidence in support of the four-stage reaction-erosion model reported in previous literature, and show that this model applies to polymer degradation in heavy water and in a buffer made from D2O/H2O 50:50. It is believed that this is the first time that NRA and MRI have been compared for the same hydrating system.  相似文献   
58.
Nitric oxide (NO) is involved in many biological processes. Aromatic ortho-diamine derivatives are commonly used in the fluorescence imaging of NO in living cells. ortho-diamino (o-diamino) compounds are believed to react with NO in an oxygenated medium leading to the formation of a triazole derivative. One such o-diamino compound, 1,2-diaminoanthraquinone (DAA), is a nontoxic probe for the detection of NO in living tissues and cells. The formation of the DAA triazole derivative (DAA-TZ) upon reaction of DAA with NO/O(2) within cells has not been demonstrated previously. The aim of this study was to confirm that DAA-TZ is the species formed intracellularly when DAA reacts with NO in the presence of oxygen. The chemical synthesis and characterisation of DAA-TZ was performed together with intracellular studies of DAA and DAA-TZ. Raw 264.7 macrophages were loaded with the DAA or DAA-TZ under conditions of no-stimulation or stimulation with interferon-γ and lipopolysaccharide to produce NO. Confocal microscopy was used to image the DAA-loaded macrophage cells. Analysis of the emission spectra allowed precise discrimination of the fluorescence of each species in the macrophage cells, and confirmed the identity of DAA-TZ as the intracellular reaction product between DAA and NO in the presence of oxygen.  相似文献   
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60.
Wet oxidation of phenol aqueous solutions was carried out in a fixed bed reactor operating in trickle flow regime. Mild conditions of temperature (140°C) and oxygen partial pressure (1–9 bar) were used. Three active carbons and one commercially available supported copper catalyst were tested as catalytic material. Previous studies demonstrated that active carbon gives higher phenol conversion than conventional oxidation catalysts, although significant loss of active carbon due to combustion was also found. In the present study, the combustion of the active carbon during the process is highly reduced by lowering the oxygen partial pressure from 9 to 2 bar, maintaining an acceptable phenol conversion. The comparison of the performance of three different active carbons shows that their physical and chemical characteristics largely influence on the phenol conversion achieved.  相似文献   
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