Over the past 10 years, the Peruvian National Tuberculosis (TB) Program, the National Reference Laboratory (NRL), Socios en Salud, and US partners have worked to strengthen the national TB laboratory...Full Text Available
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One hundred and fifty patients requiring maintenance haemodialysis were investigated to determine the incidence and pattern of tuberculosis. Twenty patients were found to have tuberculosis, giving an...Full Text Available
Personas en alto riesgo Adultos de 65 años y mayores Asma Cáncer Diabetes VIH/ SIDA Embarazadas Niños pequeños Padres Trabajadores de cuidados de salud Escuelas y...
Personas en alto riesgo Adultos de 65 años y mayores Asma Cáncer Diabetes VIH/ SIDA Embarazadas Niños pequeños Padres Trabajadores de cuidados de salud Escuelas y...
BackgroundTo identify the differential tuberculosis (TB) characteristics within the immigrant population with respect to natives in Spain.Methodology/Principal...Full Text Available
BACKGROUNDNew diagnostic tools are urgently needed to interrupt the transmission of tuberculosis and multidrug-resistant tuberculosis. Rapid,...Full Text Available
The study of genetic variability within natural populations of pathogens may provide insight into their evolution and pathogenesis. We used a Mycobacterium tuberculosis high-density...Full Text Available
BackgroundGhana has not conducted a national tuberculin survey or tuberculosis prevalence survey since the establishment of the National Tuberculosis Control Programme. The primary...Full Text Available
We reported three cases of acute intracranial tuberculosis including miliary tuberculosis, basal meningitis, tuberculomas and neuritis of cranial nerves. All patients had native and contrast enhanced CT and MRI scans. MRI revealed more granulomas and a better imaging contrast in the detection of basal meningitis. Neuritis was diagnosed only with the MRI. MRI scans should be prefered as the imaging procedure in clinically presumed intracranial tuberculosis. (orig.).
-Estudio sobre la fijacion de nitrogeno, fotosintesis y reconolizacion ... - Fotosintesis y relaciones hidricas en liquenes nanofruticulosos antarticos. ...
We ran a comparative analysis of all patients for whom a positive culture of Mycobacterium tuberculosis complex was available between April 2004 and October 2005 and whose HIV serology...Full Text Available
Mycobacterium tuberculosis is one of the strongest reducers of nitrate in the genus Mycobacterium. Under microaerobic conditions, whole cells exhibit upregulation of...Full Text Available
BackgroundRifampin is a key drug in antituberculosis chemotherapy because it rapidly kills the majority of bacilli in tuberculosis lesions, prevents relapse and thus enables 6-month...Full Text Available
Multidrug-resistant tuberculosis is an increasing public health concern in many parts of the world, especially in low-income countries, where most cases occur. Traditional drug susceptibility testing...Full Text Available
We have evaluated the performance of two rapid, low-cost methods for the detection of ofloxacin (OFX) resistance with 95 Mycobacterium tuberculosis isolates from countries with high...Full Text Available
Mycolic acids are key cell wall components for the survival, pathogenicity, and antibiotic resistance of the human tubercle bacillus. Although it was thought that Mycobacterium tuberculosis...Full Text Available
Mycobacterium tuberculosis is the etiologic agent of tuberculosis and can be accurately detected by laboratories using commercial genetic tests. Nontuberculosis mycobacteria (NTM) causing other mycobacterioses...Full Text Available
To confirm that Mycobacterium tuberculosis chaperonin 10 (Cpn10) is secreted outside the live bacillus, infected macrophages were examined by electron microscopy. This revealed that...Full Text Available
Purpose of reviewPhysicians, researchers and policy makers must understand the myriad consequences of multidrug and extensively drug-resistant tuberculosis (TB) within...Full Text Available
Background The scale-up of treatment for HIV and multidrug-resistant tuberculosis (MDR-TB) in developing countries requires a long-term relationship with the...Full Text Available
SummaryMycobacterium tuberculosis has 10 universal stress proteins, whose function is unknown. However, proteomic and transcriptomic analyses have shown that a number...Full Text Available
In this work, we describe the activity of ACH-702 against clinical isolates of Mycobacterium tuberculosis and six different nontuberculous mycobacteria. The MIC50 and MIC90...Full Text Available
BackgroundDiagnostic delay in patients with tuberculosis (TB) leads to ongoing TB transmission, higher mortality rates and increased patient and government health expenditure. Qualitative...Full Text Available
The aim of this study was to evaluate a nitrate reductase assay (NRA) performed on smear-positive sputa for the direct detection of rifampin resistance in Mycobacterium tuberculosis....Full Text Available
The direct detection of pyrazinamide resistance in Mycobacterium tuberculosis is sufficiently difficult that many laboratories do not attempt it. Most pyrazinamide resistance is caused...Full Text Available
Current methods for drug susceptibility testing of Mycobacterium tuberculosis are either costly or slow. As the prevalence of multidrug-resistant strains increases, the need for fast,...Full Text Available
Exposure of Mycobacterium tuberculosis to hypoxia is known to alter the expression of many genes, including ones thought to be involved in latency, via the transcription factor DevR...Full Text Available
Tuberculosis (TB) is a major threat to global health, recently exacerbated by the emergence of highly drug-resistant forms of the disease-causing pathogen and synergy with HIV/AIDS. In 2006, the Stop...Full Text Available
BackgroundTuberculosis (TB) is the most common opportunistic infection in HIV-infected adults in developing countries. Isoniazid (INH) is recommended for treatment of latent TB infection,...Full Text Available
The distribution of 20 variable regions resulting from insertion-deletion events in the genomes of the tubercle bacilli has been evaluated in a total of 100 strains of Mycobacterium tuberculosis,...Full Text Available
13 Oct 2010 ... Cuando la resina se endureci?, Chen la coloc? en una c?mara de vac?o para depositar una delgada capa de aluminio reflector sobre la ...
Understanding the physical characteristics of the local microenvironment in which Mycobacterium tuberculosis resides is an important goal that may allow the targeting of metabolic processes...Full Text Available
For rapid and low-cost detection of multidrug-resistant (MDR) Mycobacterium tuberculosis, we applied the nitrate reductase assay (NRA) using a liquid medium directly to sputum samples....Full Text Available
BackgroundSouth Africa has a high tuberculosis (TB)-human immunodeficiency virus (HIV) coinfection rate of 73%, yet only 46% of TB patients are tested for HIV. To date, relatively...Full Text Available
Bovine tuberculosis is a major problem in many countries; hence, new and better diagnostic tools are urgently needed. In this work, we have tested ESAT6, CFP10, PE13, PE5, MPB70, TB10.4, and TB27.4...Full Text Available
In monocytes, sulfatide, a lipid from Mycobacterium tuberculosis, blocked priming for enhanced release of superoxide (O2-) by the macrophage activating factors lipopolysaccharide, gamma interferon,...Full Text Available
A total of 204 isoniazid (INH)-resistant strains of Mycobacterium tuberculosis isolated from different patients in the northwestern region of Russia from 1996 to 2001 were screened...Full Text Available
The sensitivity and specificity of the MGIT TBc identification (TBc ID) test for Mycobacterium tuberculosis complex (MTC) detection in positive Bactec MGIT cultures were 95.2% and 99.2%, respectively. When MTC-positive results obtained from two additional molecular methods were included, the sensitivity of the MGIT TBc ID test was 85.4%, while that of culture was 95.7%. PMID:21450949
The gene Rv1885c from the genome of Mycobacterium tuberculosis H37Rv encodes a monofunctional and secreted chorismate mutase (*MtCM) with a 33-amino-acid...Full Text Available
Fifty-six tuberculosis patients and twenty-eight control subjects were evaluated in a comprehensive investigation of cellular and humoral immune function in pulmonary TB. The patient group showed significantly...Full Text Available
The production, principal applications, characteristics and properties, advantages of the gas natural is showed. A sectorial overview of the ceramic industry and the utilization of the natural gas in the ceramic industry is presented. The expectations are systematized and the impact of the natural gas utilization in the ceramic industry is evaluated. Some conclusions are withdrawn and recommendations suggested.
Evidence suggests that insertion of the IS6110 element is not without consequence to the biology of Mycobacterium tuberculosis complex strains. Thus, mapping of multiple IS6110 insertion sites in the genome of biomedically relevant clinical isolates would result in a better understanding of the role of this mobile element, particularly with regard to transmission, adaptability and virulence. In the present paper, we describe a versatile strategy, referred to as GL-PCR, that amplifies IS6110-flanking sequences based on the construction of a genomic library. M. tuberculosis chromosomal DNA is fully digested with HincII and then ligated into a plasmid vector between T7 and T3 promoter sequences. The ligation reaction product is transformed into Escherichia coli and selective PCR amplification...
BackgroundBuruli ulcer, the third mycobacterial disease after tuberculosis and leprosy, is caused by the environmental mycobacterium M. ulcerans. Various modes of...Full Text Available
BackgroundSurrogate immunologic markers for natural and vaccine-mediated protection against tuberculosis (TB) have not been identified.MethodsHIV-infected...Full Text Available
We reported three cases of acute intracranial tuberculosis including miliary tuberculosis, basal meningitis, tuberculomas and neuritis of cranial nerves. All patients had native and contrast enhanced CT and MRI scans. MRI revealed more granulomas and a better imaging contrast in the detection of basal meningitis. Neuritis was diagnosed only with the MRI. MRI scans should be prefered as the imaging procedure in clinically presumed intracranial tuberculosis. (orig.) [Deutsch] Die Befunde von drei Patienten mit intrakranieller Tuberkulose (intrakranielle Miliartuberkulose, Meningitis tuberculosa, Neuritis und Tuberkulome) in der Magnetresonanztomographie (MRT) wurden mit der Computertomographie (CT) verglichen. Sowohl die MRT als auch die CT wurden nativ und nach Kontrastmittelgabe durchgefuehrt. Die MRT zeigte sich im Nachweis von Granulomen insbesondere im Bereich des Hirnstamms ueberlegen. Ebenso wurde ein hoeherer ...
We used computerized tomography (CT) in the study of eight patients with macronodular splenic tuberculosis prior to the microbiological diagnosis. These patients underwent additional CT controls during and after tuberculostatic therapy. All the patients studed presented the acquired immunodeficiency syndrome (AIDS). Splenomegaly and numerosous round, hypodense lesions that showed no contrast uptake were found in all the subjects. Only three patients presented evidence of tuberculosis in plain radiography and/or chest X-ray. Two patients presented abdominal lymph nodes. None of them showed evidence of hepatic lesions or ascites. follow-up CT scans revealed a progressive reduction of the lesions, which eventually disappeared completely, and splenomegaly was considerably reduced. Anthough it is uncommon, we should suspect splenic involvement in tuberculosis if the clinical and radiological contexts are appropriate. CT provides ...
Patent medicine vendors (PMVs) are a ubiquitous feature of the informal health sector in Nigeria. A previous study on healthcare-seeking behaviour of persons with chronic cough in southern Nigeria found...Full Text Available
Mycobacterium ulcerans is the causative agent of Buruli ulcer, the third most common mycobacterial disease after tuberculosis and leprosy. It is an emerging infectious disease that...Full Text Available
BackgroundSeveral diseases, many of which nowadays pandemic, consist of multifactorial pathologies. Paradigmatic examples come from the immune response to pathogens, in which cases...Full Text Available
PknB is a member of the newly discovered eukaryotic-like protein serine/threonine kinase (PSTK) family of proteins. The pknB gene was cloned and expressed in Escherichia coli....Full Text Available
BackgroundTraumatic pneumothoraces are common. Many are managed with tube thoracostomy. However, there is a high complication rate from chest tube placement, particularly in patients...Full Text Available
Summary The steadily growing epidemic of diabetes mellitus poses a threat for global tuberculosis (TB) control. Previous studies have identified an important association between diabetes mellitus and TB. However, these studies have limitations: very few were carried out in low-income countries, with none in Africa, raising uncertainty about the strength of the diabetes mellitus-TB association in these settings, and many critical questions remain unanswered. An expert meeting was held in November 2009 to discuss where there was sufficient evidence to make firm recommendations about joint management of both diseases, to address research gaps and to develop a research agenda. Ten key research questions were identified, of which 4 were selected as high priority: (i) whether, when and how to sc...
Summary Objective To evaluate the cost-effectiveness of an educational outreach intervention to improve primary respiratory care by South African nurses. Methods Cost-effectiveness analysis alongside a pragmatic cluster randomised controlled trial, with individual patient data. The intervention, the Practical Approach to Lung Health in South Africa (PALSA), comprised educational outreach based on syndromic clinical practice guidelines for tuberculosis, asthma, chronic obstructive pulmonary disease, pneumonia and other respiratory diseases. The study included 1999 patients aged 15 or over with cough or difficult breathing, attending 40 primary care clinics staffed by nurses in the Free State province. They were interviewed at first presentation, and 1856 (93%) were interviewed 3 months late...
TH1 cytokine secretion was examined in response to synthetic peptides of the 85A component of the major secreted, fibronectin-binding antigen 85 complex from Mycobacterium tuberculosis in seven different...Full Text Available
ObjectivesThe aim of this study was to comprehensively evaluate the antibacterial activity and MurE inhibition of a set of N-methyl-2-alkenyl-4-quinolones found...Full Text Available
This document contains the technical proceedings of the 19 national seminar on the rational use of energy and exposition of equipment and services, organized by the Asociacion de Tecnicos y Pofesionistas en Aplicacion Energetica (ATPAE) (Association of Technicians and Professionals on Energy Application) conducted in Mexico City on September 21-25, 1998. This seminar encompassed subjects such as: energy saving in the energy sector, energy efficiency in industrial processes and practical developments, practical cases of energy saving in industry, energy saving in buildings, transportation, non-renewable energy utilization and environmental impact and eco-energies. [Espanol] Este documento contiene la memoria tecnica del 19 seminario nacional sobre el uso racional de la energia y exposicion de equipos y servicios, organizado por la Asociacion de Tecnicos y Profesionistas en Aplicacion Energetica (ATPAE), en Mexico, D.F, los dias 21-25 de septiembre de 1998. Este ...
The present study was aimed to investigate antimicrobial potential of Glycyrrhiza glabra roots. Antimycobacterial activity of Glycyrrhiza glabra was found at 500mg/mL concentration. Bioactivity guided phytochemical analysis identified glabridin as potentially active against both Mycobacterium tuberculosis H37Ra and H37Rv strains at 29.16mg/mL concentration. It exhibited antimicrobial activity against both Gram-positive and Gram-negative bacteria. Our results indicate potential use of licorice as antitubercular agent through systemic experiments and sophisticated anti-TB assay.
The authors carried out a retrospective study on 4 years' work on a series of patients with proved active tuberculosis examined in the Departments of Bronchopneumology and Infectious Disease of the Arezzo Civil Hospital. The population was heterogenerous from the immunologic viewpoint. This paper compared the effectiveness of Computed Tomography (CT) with that of conventional chest radiography (CR) in the diagnosis and prognosis of tuberculosis. All patients underwent chest CR in double projection and conventional CT studies of the chest; 16 patients were also submitted to high resolution CT (HRCT). Consolidation was the most frequent parenchymal lesion in immunocompetent patients; it was often associated with cavitation, with no clear topographic prevalence in the upper lobes. Pleural effusion, as the only sign of disease and with empyema features, was found in 10 immunocompetent patients. No predominant pattern was found in the other two ...
Some of well known F{sub 2} layer anomalies might have their origin in lower atmosphere and some have extra terrestrial sources. It has been suggested that the phenomena occurring below the ionosphere such as thunderstorms, lightning/sprites, volcanic eruptions and earthquakes and above the phenomena like corona mass ejection, solar flares and extra terrestrial events may produce F{sub 2} layer signatures. In the present paper we have tried to summarize the effect of some phenomena occurring below the ionosphere like thunderstorms, lightning/sprites and seismic activity and the phenomena such as solar flares which occur above the ionosphere, on the ionospheric electron and ion temperatures. The paper also discusses possibilities. The ionospheric electron and ion temperatures were measured by the RrPAa payload aboard the Iindian SRrOSS-C2 satellite. The normal day's ion and electron temperatures have been compared to the temperatures recorded during the disturbed day. The ...
Introduccion y objetivos Aunque los bloqueos de rama (BR) se consideran hallazgos frecuentes, la informacion sobre su prevalencia real en la poblacion general es escasa, y es inexistente en los pacientes en dialisis. El objetivo es establecer la prevalencia del BR completo en la poblacion que inicia dialisis y los factores relacionados con su aparicion. Como analisis adicional, se explora su asociacion con la mortalidad y con la aparicion de un evento cardiovascular. Metodos Se incluyo a los pacientes que iniciaron dialisis en nuestro centro entre el 1 de noviembre de 2003 y el 31 de diciembre de 2006. Todos fueron sometidos a valoracion cardiologica al inicio de dialisis. Determinamos el BR y su relacion con factores clinicos y parametros ecocardiograficos y bioquimicos. Los pacientes fue...
The United Nations Framework Convention on Climate Change (UNFCCC) was approved in 1992 to respond to the worl-wide concern about the warming of the planet. The primary target was the stabilization of the concentration of greenhouse gases in the atmosphere, in an attempt to reduce to the minimum the degradation of the environment caused by humans. By virtue of the Convention, the Parts2 are committed to reach their objectives in the reduction of the emissions. A Conference of the Parts was stablished to promote the effective application of the Convention. The third Conference of the Parts, celebrated in Kyoto (Japan, 1997) approved, by consensus, the denominated Kyoto Protocol, in which 39 developed countries and countries with economies in transition were committed to reduce their emissions of greenhouse gases between years 2008 and 2012 in a 5.2 global percent with respect to the 1990 levels. Three {sup f}lexibility mechanisms{sup w}ere stablished to help the Parts to reach their ...
In order to evaluate the effects of radioactivity on active vegetal substances, samples of Fennel (Foeniculum vulgare Miller., fructus), Guarana (Paulinia cupana, Kunth, semen), Gingko (gingko biloba, L., folium), and Kawa-Kawa (Piper methysticum G. Forst, rhizoma), were treated with scaling doses (0 to 25 KGy) of gamma radiation (Co{sup 60}). The 'blind test' methodology was used. The active substances from each sample were analysed by qualitative and quantitative methods after radiation. There were no significant differences seen between the control sample (0 KGy) and the irradiated samples. Microbe contamination was significantly reduced, about 10000 CFU/g, with the initial 5 KGy dose. It was concluded that gamma radiation can be used as an alternative procedure to reduce microbiologic contamination in medicinal plants. Before this procedure can be extended to other medicinal plants, more specific analytical methods are recommended to verify possible structural ...
The success in developing of the oil industry operating in offshore-onshore terminals, connected by pipelines with the facilities of the coastal zone, can be attributed partially to the beach morpho dynamic monitoring. This study represents a solution to the concerns of the technical operations in coastal zones because it minimizes the impact of the petroleum production and it assures the environmental protection associated to the risks of the pipelines breaking. This impact type results mainly of the vertical and horizontal displacements of the beach, from the coastal dunes to the shore face. The mobility of the profile is associated to the magnitude of the sedimentary processes, which reproduce naturally or not, in scale of time that can vary among few days, years or decades. For the monitoring and interpretation of the beach profile mobility the following methods are recommended: calculation of the closure depth with base in the wave data; bathymetric survey with sled; calculation ...
Tumour necrosis factor-alpha (TNF-?) antagonist drugs have been associated with increased risk of tuberculosis (TB). Tuberculin skin test (TST) is the most frequently used tool for identification of latent TB infection. We herein aimed to analyse the effect of TNF-? antagonists on the TST responses in a prospective study. The study group consisted of 182 patients (99 female, 83 male) who received TNF-? antagonists for various rheumatic disorders. All patients were evaluated with TST along with other parameters on the day of referral and on the 12th month visit. For those patients with a response of <5?mm induration at the initial evaluation, the TST was repeated to observe the booster effect. Out of 182 patients, 87 patients (48%) had a negative (0?4?mm) and 95 (52%) had a positive (?5?mm)...
Exposure to crystalline silica dust causes multiple diseases, but silicosis and silica dust-associated tuberculosis (TB), in particular, are the two diseases that remain high on the list of occupational health priorities in low-income countries and that still occur in some high-income countries. The prevalence of silica-related TB is exacerbated by the human immunodeficiency virus (HIV) epidemic in low-income countries. This review describes the morphology of silica and the variable potency of the different forms. Sources of crystalline silica are discussed, with emphasis on less commonly recognised sources, such as small-scale mining operations and agriculture. Trends in the prevalence of silicosis are also presented. Although efforts have been made for many years in most countries to reduce silica dust levels, silicosis continues to occur even in young people. The clinical and pathological features and diagnosis of silicosis, with emphasis on chest radiography, ...
Both solvent extraction and spectrophotometric techniques were used to show the alterations that gamma radiation causes in the behavior of tetracycline molecule as far as its extracting and complexing power are concerned. The effect of gamma radiation on the solid tetracycline molecule, benzyl alcohol and on the solution of both was examined in solvent extraction systems whose aqueous phases were made up by {sup 152} Eu-{sup 154}Eu radioactive tracer solutions and whose organic phases were constituted by tetracycline-benzyl alcohol solutions. Experiments were performed in order to determine whether or not the water used for the pre-saturation of benzyl alcohol would influence the radiolysis of tetracycline. Solvent extraction and spectrophotometry were the techniques used to obtain the necessary data. Absorption spectra of irradiated tetracycline benzyl alcohol solutions submitted to several gamma radiation doses were examined and the alterations shown by these spectra were examined. ...
The number of ERP (Enterprise Resource Planning) implementations within the oil industry has increased substantially in the past years. PETROBRAS has recently developed a business case, a 10 steps methodology developed by Symnetics-Benchmarking Partners (management consultancy), aimed at enhancing strategic and tangible ROI - Return on Investment of IT projects. The Business Case has not only provided alignment of PETROBRAS strategies with ERP capabilities, but also identified process gaps and opportunities for improvement as well as developing a high level implementation plan including timing, costs and potential benefits. Anticipated economic gains were mainly focused on the following business processes: materials management (30%), planning and controlling (25%), project management (24%) and order fulfillment (14%). PETROBRAS has chosen a phased approach for implementing the ERP. Two scenarios were considered: time, cost, risk and scope were the key issues regarding the ERP ...
A plan has been put forth to strategically thin northern California forests to reduce fire danger and improve forest health. The resulting biomass residue, instead of being open burned, can be converted into ethanol that can be used as a fuel oxygenate or an octane enhancer. Economic potential for a biomass-to-ethanol facility using this softwood biomass was evaluated for two cases: Stand-alone and co-located. The co-located case refers to a specific site with an existing biomass power facility owned by Wheelabrator Environmental Systems Inc. near Martell, California. A two-stage dilute acid hydrolysis process is used for the production of ethanol from softwoods, and the residual lignin is used to generate steam and electricity. For a plant processing 800 dry tonnes per day of feedstock, the co-located case is an economically attractive concept. Total estimated capital investment is approximately $ 70 million for the co-located case. The resulting internal rate of return is about 24% ...
The use of medicinal plants in the treatment of diseases has increased significantly in the last years, as has research concerning chemical characterization of these plants. In this study, inorganic constituents were determined in leaves and in extracts from three medicinal plant species of the Casearia genus (C. sylvestris, C. decandra and C. obliqua) collected in distinct regions of the Atlantic Forest, SP. The elemental compositions of the soils in which these plants were grown were also determined. Traditionally, these plants are used due to their antiinflammatory, antiacid, antiseptic and cicatrizing properties. The antiulcer and the antitumor activities of the Casearia genus and its capacity to neutralize snake and bee venoms, have also been scientifically confirmed. The analytical methodology used was neutron activation analysis. Long and short irradiation periods of the samples and the standards were carried out at IPEN's IEA-R1 nuclear research reactor. In the leaf K ...
The GntR-like protein NorG has been shown to affect Staphylococcus aureus genes involved in the resistance to quinolones and ?-lactams, such as those encoding the NorB and AbcA transporters. To identify the target genes regulated by NorG, we carried out transcriptional profiling assays using S. aureus RN6390 and its isogenic norG::cat mutant. Our data showed that NorG positively affected the transcription of global regulators mgrA, arlS, and sarZ. The three putative drug efflux pump genes most positively affected by NorG were the NorB efflux pump (5.1-fold), the MmpL-like protein SACOL2566 (5.2-fold), and the BcrA-like drug transporter SACOL2525 (5.7-fold). The S. aureus predicted MmpL protein showed 53% homology with the MmpL lipid transporter of Mycobacterium tuberculosis, and the putative SACOL2525 protein showed 87% homology with the bacitracin drug transporter BcrA of Staphylococcus hominis. Two pump genes most negatively affected by NorG were NorC (4-fold) ...
A unique feature of cyanobacteria genomes is the abundance of genes that code for hypothetical proteins containing tandem pentapeptide repeats approximately described by the consensus motif A(N/D)LXX. To date, the structures of two pentapeptide-repeat proteins (PRPs) have been determined, with the tandem pentapeptide-repeat sequences observed to adopt a novel type of right-handed quadrilateral ?-helix, or Rfr-fold, in both structures. One structure, Mycobacterium tuberculosis MfpA, is a 183-residue protein that contains 30 consecutive pentapeptide repeats and appears to offer antibiotic resistance by acting as a DNA mimic. The other structure, Cyanothece 51142 Rfr32, is a 167-residue protein that contains 21 consecutive pentapeptide repeats. The function of Rfr32, like the other 35 hypothetical PRPs identified in the genome of Cyanothece, is unknown. In an effort to understand the role of PRPs in cyanobacteria and to better characterize the structural properties of ...
In the geologic formation where the oil deposits are located, diverse types of rocks perform functions as structural elements, storage containers for hydrocarbon water and calorific energy, as well as impermeable barriers and transport means of the energy and the fluids. Among the most important properties that are used to describe these functions are the porosity, the permeability, the compressibility of the pores volume, the formation resistivity factor, the saturation exponent, the velocity of acoustic waves P and S, the relative permeability, the capillary pressures, the elastic constants and other mechanical properties, the thermal expansion, coefficient, the thermal conductivity, the thermal diffusivity and the specific heat. The execution of an ample variety of activities related to the stages of exploration, location, evaluation and development of the oil deposits, depends strongly on having a good knowledge of the magnitude and the spatial variability of these properties. The ...