Showing papers by "Universidade Federal de Minas Gerais published in 2003"
TL;DR: Findings identify Mas as a functional receptor for Ang-(1–7) and provide a clear molecular basis for the physiological actions of this biologically active peptide.
Abstract: The renin-angiotensin system plays a critical role in blood pressure control and body fluid and electrolyte homeostasis. Besides angiotensin (Ang) II, other Ang peptides, such as Ang III [Ang-(2-8)], Ang IV [Ang-(3-8)], and Ang-(1-7) may also have important biological activities. Ang-(1-7) has become an angiotensin of interest in the past few years, because its cardiovascular and baroreflex actions counteract those of Ang II. Unique angiotensin-binding sites specific for this heptapeptide and studies with a selective Ang-(1-7) antagonist indicated the existence of a distinct Ang-(1-7) receptor. We demonstrate that genetic deletion of the G protein-coupled receptor encoded by the Mas protooncogene abolishes the binding of Ang-(1-7) to mouse kidneys. Accordingly, Mas-deficient mice completely lack the antidiuretic action of Ang-(1-7) after an acute water load. Ang-(1-7) binds to Mas-transfected cells and elicits arachidonic acid release. Furthermore, Mas-deficient aortas lose their Ang-(1-7)-induced relaxation response. Collectively, these findings identify Mas as a functional receptor for Ang-(1-7) and provide a clear molecular basis for the physiological actions of this biologically active peptide.
1,639 citations
TL;DR: In this paper, the basic concepts and characteristics of Raman spectra from carbon nanotubes (both isolated and bundled) are presented, with the focus directed toward their use for carbon Nanotube characterization.
Abstract: The basic concepts and characteristics of Raman spectra from carbon nanotubes (both isolated and bundled) are presented. The general characteristics of the radial breathing mode, tangential mode (G band), disorder-induced mode (D-band) and other Raman features are presented, with the focus directed toward their use for carbon nanotube characterization. Polarization analysis, surface enhanced Raman spectroscopy and complementary optical techniques are also discussed in terms of their advantages and limitations.
990 citations
TL;DR: The data suggest that in Brazil, at an individual level, color, as determined by physical evaluation, is a poor predictor of genomic African ancestry, estimated by molecular markers.
Abstract: This work was undertaken to ascertain to what degree the physical appearance of a Brazilian individual was predictive of genomic African ancestry. Using a panel of 10 population-specific alleles, we assigned to each person an African ancestry index (AAI). The procedure was able to tell apart, with no overlaps, 20 males from northern Portugal from 20 males from Sao Tome Island on the west coast of Africa. We also tested 10 Brazilian Amerindians and observed that their AAI values fell in the same range as the Europeans. Finally, we studied two different Brazilian population samples. The first consisted of 173 individuals from a rural Southeastern community, clinically classified according to their Color (white, black, or intermediate) with a multivariate evaluation based on skin pigmentation in the medial part of the arm, hair color and texture, and the shape of the nose and lips. In contrast to the clear-cut results with the African and European samples, our results showed large variances and extensive overlaps among the three Color categories. We next embarked on a study of 200 unrelated Brazilian white males who originated from cosmopolitan centers of the four major geographic regions of the country. The results showed AAI values intermediate between Europeans and Africans, even in southern Brazil, a region predominantly peopled by European immigrants. Our data suggest that in Brazil, at an individual level, color, as determined by physical evaluation, is a poor predictor of genomic African ancestry, estimated by molecular markers.
892 citations
TL;DR: The more significant bioactivities of a variety of semicarbazones (anti-protozoa, anticonvulsant) and thiosemicarbazone and their metal complexes are reviewed together with proposed mechanisms of action and structure-activity relationships.
Abstract: The more significant bioactivities of a variety of semicarbazones (anti-protozoa, anticonvulsant) and thiosemicarbazones (antibacterial, antifungal, antitumoral, antiviral) and their metal complexes are reviewed together with proposed mechanisms of action and structure-activity relationships. Clinical or potential pharmacological applications of these versatile compounds are discussed.
669 citations
TL;DR: In the case of Brazil, a sharp and widespread fertility decline began by the end of the 1960s and an accelerated population aging process can thus be expected as mentioned in this paper, which will necessarily be faster and with deeper structural changes, demographically speaking, than in First World countries, for two reasons: fertility decline in Brazil was faster, and it took place in a population with a younger age structure.
Abstract: Contrary to common sense, the population aging process is due to the decline in fertility rather than mortality. The aging process began around the end of the 19th century in a number of Western European countries, expanded to the rest of the so-called First World over the past century, and reached several Third World countries afterwards, including Brazil over the last decades. In the Brazilian case, a sharp and widespread fertility decline began by the end of the 1960s, and an accelerated population aging process can thus be expected. This process will necessarily be faster and with deeper structural changes, demographically speaking, than in First World countries, for two reasons: the fertility decline in Brazil was faster, and it took place in a population with a younger age structure.
473 citations
TL;DR: The results show that prevalence rates for at least one chronic disease, hypertension, arthritis, and inability to feed oneself/bathe/use the toilet among Brazilian seniors are very similar to those observed in other populations.
Abstract: The objective of this research was to describe health conditions and health services utilization among Brazilian seniors. The study was based on 28,943 adults > 60 years (99.9%) from an overall National Household Survey (PNAD 1998). The results show that prevalence rates for at least one chronic disease (69.0%), hypertension (43.9%), arthritis (37.5%), and inability to feed oneself/bathe/use the toilet (2.0%) are very similar to those observed in other populations. Physician visits and hospitalization patterns are within the variation reported by different countries. The low prevalence rates of older adults who had interrupted activities because of a health problem (13.9%) or had been bedridden (9.5%) in the previous 2 weeks or hospitalized in the previous year (13.6%) show that the vast majority are not subject to these events. Considering that 50% of this population live on less than or equal to one Brazilian monthly minimum wage, expenditures on medications consume approximately one-fourth (23%) of total income for half of the elderly population.
401 citations
TL;DR: American cutaneous leishmaniasis is endemic in widespread areas of Latin America and is most common in persons working at the edge of the forest and among rural settlers, and for treatment two pentavalent antimony-containing drugs are used.
Abstract: American cutaneous leishmaniasis is endemic in widespread areas of Latin America. The causative agents include L. (V.) braziliensis, L. (L.) mexicana, L. (V.) panamensis, and related species. The spectrum of disease includes single, localized, cutaneous ulcers, diffuse cutaneous leishmaniasis, and mucosal disease. The main reservoirs for L. (V.) braziliensis and other Leishmania (Vianna) spp. are small forest rodents. The vectors are ground-dwelling or arboreal Lutzomyia sandflies, which are abundant in the forest. Disease is most common in persons working at the edge of the forest and among rural settlers. The incubation period of cutaneous leishmaniasis varies from two weeks to several months. A wide variety of skin manifestations ranging from small, dry, crusted lesions to large, deep, mutilating ulcers may be seen. Ulcerative lesions are usually shallow and circular with well-defined, raised borders and a bed of granulation tissue. In L. (V.) braziliensis infection, regional lymphadenopathy often precedes the development of cutaneous lesions by one to 12 weeks. A definite diagnosis depends on the identification of amastigotes in tissue or promastigotes in culture. Antileishmanial antibodies are present in the serum of some patients with cutaneous leishmaniasis as detected by ELISA, immunofluorescent assays, direct agglutination tests or other assays, but the titers are usually low. The leishmanin skin test result usually becomes positive during the course of the disease. For treatment two pentavalent antimony-containing drugs are used: stibogluconate sodium, and meglumine antimoniate (Glucantime). Amphotericin B deoxycholate is an alternative for persons who fail to respond to pentavalent antimony. Immunoprophylaxis and immunotherapy are promising new approaches to prevention and treatment.
394 citations
TL;DR: The findings show that the nucleus contains a nucleoplasmic reticulum with the capacity to regulate calcium signals in localized subnuclear regions and provides a potential mechanism by which calcium can simultaneously regulate many independent processes in the nucleus.
Abstract: Calcium is a second messenger in virtually all cells and tissues1. Calcium signals in the nucleus have effects on gene transcription and cell growth that are distinct from those of cytosolic calcium signals; however, it is unknown how nuclear calcium signals are regulated. Here we identify a reticular network of nuclear calcium stores that is continuous with the endoplasmic reticulum and the nuclear envelope. This network expresses inositol 1,4,5-trisphosphate (InsP3) receptors, and the nuclear component of InsP3-mediated calcium signals begins in its locality. Stimulation of these receptors with a little InsP3 results in small calcium signals that are initiated in this region of the nucleus. Localized release of calcium in the nucleus causes nuclear protein kinase C (PKC) to translocate to the region of the nuclear envelope, whereas release of calcium in the cytosol induces translocation of cytosolic PKC to the plasma membrane. Our findings show that the nucleus contains a nucleoplasmic reticulum with the capacity to regulate calcium signals in localized subnuclear regions. The presence of such machinery provides a potential mechanism by which calcium can simultaneously regulate many independent processes in the nucleus.
358 citations
TL;DR: In this article, the adsorption features of clays with the magnetic properties of iron oxides have been combined in a composite to produce a magnetic adsorbent for contaminants in water and can be subsequently removed from the medium by a simple magnetic process.
335 citations
TL;DR: This article presents the functional, information, and physical management architectures that take into account specific characteristics of this type of network and proposes WSN models to guide the management activities and the use of correlation in the WSN management.
Abstract: Wireless sensor networks (WSNs) are becoming an increasingly important technology that will be used in a variety of applications such as environmental monitoring, infrastructure management, public safety, medical, home and office security, transportation, and military. WSNs will also play a key role in pervasive computing where computing devices and people are connected to the Internet. Until now, WSNs and their applications have been developed without considering a management solution. This is a critical problem since networks comprising tens of thousands of nodes are expected to be used in some of the applications above. This article proposes the MANNA management architecture for WSNs. In particular, it presents the functional, information, and physical management architectures that take into account specific characteristics of this type of network. Some of them are restrict physical resources such as energy and computing power, frequent reconfiguration and adaptation, and faults caused by nodes unavailable. The MANNA architecture considers three management dimensions: functional areas, management levels, and WSN functionalities. These dimensions are specified to the management of a WSN and are the basis for a list of management functions. The article also proposes WSN models to guide the management activities and the use of correlation in the WSN management. This is a first step into a largely unexplored research area.
328 citations
TL;DR: Improved understanding of key events occurring during the complex series of host-pathogen interactions leading to enterocolitis is led to an improved understanding of the molecular pathogenesis.
Abstract: Recent studies on the molecular pathogenesis of Salmonella enterica serotype Typhimurium-induced enterocolitis using tissue culture models and the neonatal calf model have led to an improved understanding of key events occurring during the complex series of host-pathogen interactions leading to
Empresa Brasileira de Pesquisa Agropecuária1, Universidade Federal de Santa Catarina2, University of São Paulo3, National Institute of Amazonian Research4, Universidade Federal de Minas Gerais5, Federal University of Rio de Janeiro6, Federal University of Rio Grande do Norte7, University of Brasília8, Universidade Federal de Goiás9, Universidade Católica de Brasília10, Pontifícia Universidade Católica do Rio Grande do Sul11, Ludwig Institute for Cancer Research12, State University of Santa Cruz13, Federal University of Ceará14, State University of Campinas15, Sao Paulo State University16, Federal University of Pernambuco17, Pontifícia Universidade Católica do Paraná18, Federal University of Paraná19, Universidade Federal do Rio Grande do Sul20, Federal University of Alagoas21, Federal University of Pará22
TL;DR: The complete genome sequence reveals extensive alternative pathways for energy generation, complex and extensive systems for stress adaptation and motility, and widespread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism.
Abstract: Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) widespread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications.
TL;DR: An association between theProduction of IFN-γ by CD3+ CD4+ cells and morbidity in Chagas' disease, whereas the production of IL-10 by macrophages/monocytes leads to regulation of the immune response in IND patients is suggested.
Abstract: The role of interleukin 10 (IL-10) and gamma interferon (IFN-γ) on the development of pathology in human Chagas' disease was investigated. Two categories of patients, low and high producers of IFN-γ, were identified based on the levels of secretion of this cytokine in the supernatant of peripheral blood mononuclear cell (PBMC) cultures. Eighty-three percent of the patients presenting with cardiac disease (CARD) of different degrees and 59% of the patients with the indeterminate form of disease (IND) were identified as high IFN-γ producers. PBMC from IND patients classified as low IFN-γ producers secreted significantly higher amounts of IL-10 than did those from other groups. Flow cytometry analysis demonstrated that in PBMC from the IND group, the majority of the IL-10-producing cells were monocytes (CD14High+ cells), whereas in the CARD group, the major sources of IFN-γ were T lymphocytes (CD3+ CD4+ cells). These results suggest an association between the production of IFN-γ by CD3+ CD4+ cells and morbidity in Chagas' disease, whereas the production of IL-10 by macrophages/monocytes leads to regulation of the immune response in IND patients. We hypothesize that an exacerbated production of IFN-γ against Trypanosoma cruzi antigens favors the development of a strong Th1 response in CARD patients, which leads to progression of heart disease.
TL;DR: In this paper, the authors present a catalog of 108 Herbig Ae/Be candidate stars identified in the Pico dos Dias Survey, together with 19 previously known candidates and four objects selected from the IRAS Faint Source Catalog.
Abstract: We present a new catalog of 108 Herbig Ae/Be candidate stars identified in the Pico dos Dias Survey, together with 19 previously known candidates and four objects selected from the IRAS Faint Source Catalog. These 131 stars were observed with low- and/or medium-resolution spectroscopy, and we complement these data with high-resolution spectra of 39 stars. The objects present a great variety of Hα line profiles and were separated according to them. Our study suggests that most of the time a Herbig Ae/Be star will present a double peak Hα line profile. Correlations among different physical parameters, such as spectral type and v sin i with Hα line profiles were searched. We found no correlation among Hα line profiles and spectral type or v sin i except for stars with P Cygni profiles, where there is a correlation with v sin i. We also use preliminary spectral energy distributions to seek for any influence of the circumstellar medium in the Hα line profiles. The presence of [O I] and [S II] forbidden lines is used together with the Hα line profiles and these preliminary spectral energy distributions to discuss the circumstellar environment of the Herbig Ae/Be candidates. The distribution of the detected [O I] and [S II] forbidden lines among different spectral types points to a significantly higher occurrence of these lines among B stars, whereas the distribution among different Hα profile types indicates that forbidden lines are evenly distributed among each Hα line-profile type. Combining the distance estimates of the Herbig candidates with the knowledge of the interstellar medium distribution, we have found that 84 candidates can be associated with some of the more conspicuous SFRs, being in the right direction and at a compatible distance. As a further means of checking the properties of the HAeBe candidates, as well as their present evolutionary status, the derived luminosities and effective temperatures of the stars with possible association to the star-forming regions and/or Hipparcos distances were plotted together with a set of pre–main-sequence evolutionary tracks on an HR diagram. A set of 14 stars were found out of their expected positions in the HR diagram.
TL;DR: The current evidence indicates that the resting activity of RVLM presympathetic neurons is determined by the balance of powerful tonic excitatory and inhibitory synaptic inputs.
Abstract: Aim: Neurons in the rostral ventrolateral medulla (RVLM) that project directly to sympathetic preganglionic neurons in the spinal cord play a critical role in maintaining tonic activity in sympathetic vasomotor nerves. Intracellular recordings in vivo from putative RVLM presympathetic neurons have demonstrated that under resting conditions these neurons display an irregular tonic firing rate, and also receive both excitatory and inhibitory synaptic inputs. This paper will briefly review some recent findings on the role of glutamate, GABA and angiotensin II (Ang II) receptors in maintaining the tonic activity of RVLM presympathetic neurons. Results: Based on these findings, the following hypotheses will be discussed: (1) RVLM neurons receive tonic glutamatergic excitatory inputs, which originate from both medullary and supramedullary sources; (2) at least some neurons that project to and tonically inhibit RVLM presympathetic neurons are themselves tonically inhibited by GABAergic inputs originating from neurons in the caudalmost part of the ventrolateral medulla (caudal pressor area); (3) under normal conditions, Ang II receptors in the RVLM do not contribute significantly to the tonic activity of RVLM presympathetic neurons, but may do so in abnormal conditions such as heart failure or neurogenic hypertension; (4) RVLM presympathetic neurons maintain a significant level of tonic resting activity even when glutamate, GABA and Ang II receptors on the neurons are completely blocked. Under these conditions, the tonic activity is a consequence either of the intrinsic membrane properties of the neurons (autoactivity) or of synaptic inputs mediated by receptors other than glutamate, GABA or Ang II receptors. Conclusion: The current evidence indicates that the resting activity of RVLM presympathetic neurons is determined by the balance of powerful tonic excitatory and inhibitory synaptic inputs. Ang II receptors also contribute to the raised resting activity of these neurons in some pathological conditions.
TL;DR: In this paper, the optical absorption spectra of graphite and carbon nanotubes are calculated for a single-wall carbon nanophase and the chirality dependence of the absorption matrix element is analyzed analytically.
Abstract: The optical absorption spectra of \ensuremath{\pi} electrons are calculated for graphite and carbon nanotubes. Particular attention is paid to the processes contributing to the optical absorption as a function of the electron wave vector k and light polarization direction. The optical absorption amplitude around the K point in the Brillouin zone has a node in the two-dimensional Brillouin zone of graphite. The formula for the absorption scattering matrix around the K point is given analytically by expanding the matrix element into a Taylor series. The chirality dependence of the absorption matrix element of a single-wall carbon nanotube is presented.
Joseph Fourier University1, Academy of Sciences of Uzbekistan2, Universidade Federal de Minas Gerais3, Spanish National Research Council4, University of California, Berkeley5, National Council for Scientific and Technological Development6, Isaac Newton Institute7, International Trademark Association8
TL;DR: In this article, the authors report the results of a synoptic study of the photometric and spectroscopic variability of the T Tauri star AA Tau on timescales ranging from a few hours to several weeks.
Abstract: We report the results of a synoptic study of the photometric and spectroscopic variability of the classical T Tauri star AA Tau on timescales ranging from a few hours to several weeks. The AA Tau light curve had been previously shown to vary with a 8.2 d period, exhibiting a roughly constant brightness level, interrupted by quasi-cyclic fading episodes, which we interpreted as recurrent eclipses of the central star by the warped inner edge of its accretion disk (Bouvier et al. 1999). Our observations show the system is dynamic and presents non-stationary variability both in the photometry and spectroscopy. The star exhibits strong emission lines that show substantial variety and variability in their profile shapes and fluxes. Emission lines such as H and H show both infall and outflow signatures and are well reproduced by magnetospheric accretion models with moderate mass accretion rates (10 8 10 9 M yr 1 ) and high inclinations (i 60). The veiling shows variations that indicate the presence of 2 rotationally modulated hot spots corresponding to the two magnetosphere poles. It correlates well with the Hei line flux, with B V and the V excess flux. We have indications of a time delay between the main emission lines (H ,H and Hei) and veiling, the lines formed farther away preceding the veiling changes. The time delay we measure is consistent with accreted material propagating downwards the accretion columns at free fall velocity from a distance of about 8 R?. In addition, we report periodic radial velocity variations of the photospheric spectrum which might point to the existence of a 0.02 M object orbiting the star at a distance of 0.08 AU. During a few days, the eclipses disappeared, the variability of the system was strongly reduced and the line fluxes and veiling severely depressed. We argue that this episode of quiescence corresponds to the temporary disruption of the magnetic con- figuration at the disk inner edge. The smooth radial velocity variations of inflow and outflow diagnostics in the H profile yield further evidence for large scale variations of the magnetic configuration on a timescale of a month. These results may provide the first clear evidence for large scale instabilities developping in T Tauri magnetospheres as the magnetic field lines are twisted by dierential rotation between the star and the inner disk.The interaction between the inner accretion disk and the stellar magnetosphere thus appears to be a highly dynamical and time dependent process.
TL;DR: This is the first investigation to perform a more detailed and comprehensive study of the testis structure and function in domestic cats and the first report in the literature showing Sertoli and Leydig cell number per gram of testis and the daily sperm production in any kind of feline species.
Abstract: There is very little information regarding the testis structure and function in domestic cats, mainly data related to the cycle of seminiferous epithelium and sperm production. The testis weight in cats investigated in the present study was 1.2 g. Compared with most mammalian species investigated, the value of 0.08% found for testes mass related to the body mass (gonadosomatic index) in cats is very low. The tunica albuginea volume density (%) in these animals was relatively high and comprised about 19% of the testis. Seminiferous tubule and Leydig cell volume density (%) in cats were approximately 90% and 6%, respectively. The mean tubular diameter was 220 mm, and 23 m of seminiferous tubule were found per testis and per gram of testis. The frequencies of the eight stages of the cycle, characterized according to the tubular morphology system, were as follows: stage 1, 24.9%; stage 2, 12.9%; stage 3, 7.7%; stage 4, 17.6%; stage 5, 7.2%; stage 6, 11.9%; stage 7, 6.8%; and stage 8, 11 %. The premeiotic and postmeiotic stage frequency was 46% and 37%, respectively. The duration of each cycle of seminiferous epithelium was 10.4 days and the total duration of spermatogenesis based on 4.5 cycles was 46.8 days. The number of round spermatids for each pachytene primary spermatocytes (meiotic index) was 2.8, meaning that significant cell loss (30%) occurred during the two meiotic divisions. The total number of germ cells and the number of round spermatids per each Sertoli cell nucleolus at stage 1 of the cycle were 9.8 and 5.1, respectively. The Leydig cell volume was approximately 2000 mm 3 and the nucleus volume 260 mm 3 . Both Leydig and Sertoli cell numbers per gram of testis in cats were approximately 30 million. The daily sperm production per gram of testis in cats (efficiency of spermatogenesis) was approximately 16 million. To our knowledge, this is the first investigation to perform a more detailed and comprehensive study of the testis structure and function in domestic cats. Also, this is the first report in the literature showing Sertoli and Leydig cell number per gram of testis and the daily sperm production in any kind of feline species. In this regard, besides providing a background for comparative studies with other felids, the data obtained in the present work might be useful in future studies in which the domestic cat could be utilized as an appropriate receptor model for preservation of genetic stock from rare or endangered wild felines using the germ cell transplantation technique. Leydig cells, Sertoli cells, spermatogenesis, testis
TL;DR: In this article, a review of double resonance Raman spectroscopy is presented, where non-zone center phonon modes in solids can be observed in the double-resonance Raman spectrum, in which weak Raman signals appear in a wide frequency region and their combination or overtone modes can be assigned.
Abstract: A review of double resonance Raman spectroscopy is presented. Non-zone centre phonon modes in solids can be observed in the double resonance Raman spectra, in which weak Raman signals appear in a wide frequency region and their combination or overtone modes can be assigned. By changing the excitation laser energy, we can derive the phonon dispersion relations of a single nanotube.
TL;DR: A structure for simulating urban change based on estimating land use transitions using elementary probabilistic methods which draw their inspiration from Bayes’ theory and the related ‘weights of evidence’ approach is proposed.
Journal Article•
TL;DR: The potential for bioremediation applications of the microbial mer operon has been long recognized; consequently, Escherichia coli and other wild and genetically engineered organisms for the biOREmediation of Hg2+-contaminated environments have been assayed by several laboratories as mentioned in this paper.
Abstract: Mercury is present in the environment as a result of natural processes and from anthropogenic sources. The amount of mercury mobilized and released into the biosphere has increased since the beginning of the industrial age. Generally, mercury accumulates upwards through aquatic food chains, so that organisms at higher trophic levels have higher mercury concentrations. Some bacteria are able to resist heavy metal contamination through chemical transformation by reduction, oxidation, methylation and demethylation. One of the best understood biological systems for detoxifying organometallic or inorganic compounds involves the mer operon. The mer determinants, RTPCDAB, in these bacteria are often located in plasmids or transposons and can also be found in chromosomes. There are two classes of mercury resistance: narrow-spectrum specifies resistance to inorganic mercury, while broad-spectrum includes resistance to organomercurials, encoded by the gene merB. The regulatory gene merR is transcribed from a promoter that is divergently oriented from the promoter for the other mer genes. MerR regulates the expression of the structural genes of the operon in both a positive and a negative fashion. Resistance is due to Hg2+ being taken up into the cell and delivered to the NADPH-dependent flavoenzyme mercuric reductase, which catalyzes the two-electron reduction of Hg2+ to volatile, low-toxicity Hg0. The potential for bioremediation applications of the microbial mer operon has been long recognized; consequently, Escherichia coli and other wild and genetically engineered organisms for the bioremediation of Hg2+-contaminated environments have been assayed by several laboratories.
TL;DR: In this article, a simple scheme for complete Bell-state measurement of photons using hyperentangled states was proposed, which requires only linear optics and single photon detectors, and is realizable with current technology.
Abstract: We propose a simple scheme for complete Bell-state measurement of photons using hyperentangled states---entangled in multiple degrees of freedom. In addition to hyperentanglement, our scheme requires only linear optics and single photon detectors, and is realizable with current technology. At the cost of additional classical communication, our Bell-state measurement can be implemented nonlocally. We discuss the possible application of these results to quantum dense coding and quantum teleportation.
TL;DR: A2, but not LACK, fits the requirements for a safe vaccine against American leishmaniasis, and the association between rA2 and rLACK antigens in the same vaccine completely inhibited the rA 2-specific IFN-γ and humoral responses and, consequently, the protective effect of the r a2 antigen against L. amazonensis infection.
Abstract: Leishmania amazonensis is one of the major etiologic agents of a broad spectrum of clinical forms of leishmaniasis and has a wide geographical distribution in the Americas, which overlaps with the areas of transmission of many other Leishmania species. The LACK and A2 antigens are shared by various Leishmania species. A2 was previously shown to induce a potent Th1 immune response and protection against L. donovani infection in BALB/c mice. LACK is effective against L. major infection, but no significant protection against L. donovani infection was observed, in spite of the induction of a potent Th1 immune response. In an attempt to select candidate antigens for an American leishmaniasis vaccine, we investigated the protective effect of these recombinant antigens (rLACK and rA2) and recombinant interleukin-12 (rIL-12) against L. amazonensis infection in BALB/c mice. As expected, immunization with either rA2-rIL-12 or rLACK-rIL-12 induced a robust Th1 response prior to infection. However, only the BALB/c mice immunized with rA2-rIL-12 were protected against infection. Sustained gamma interferon (IFN-γ) production, high levels of anti-A2 antibodies, and low levels of parasite-specific antibodies were detected in these mice after infection. In contrast, mice immunized with rLACK-rIL-12 displayed decreased levels of IFN-γ and high levels of both anti-LACK and parasite-specific antibodies. Curiously, the association between rA2 and rLACK antigens in the same vaccine completely inhibited the rA2-specific IFN-γ and humoral responses and, consequently, the protective effect of the rA2 antigen against L. amazonensis infection. We concluded that A2, but not LACK, fits the requirements for a safe vaccine against American leishmaniasis.
TL;DR: In this paper, the structure and properties of bismuth nanowires and carbon nanotubes are discussed and compared with those of carbon nanostructures and nanoscience concepts.
TL;DR: Examining subcellular mechanisms of Ca2+ release in the HepG2 liver cell line found enriched expression of type II InsP3R in the nucleus results in greater sensitivity of the nucleus toInsP3, thus providing a mechanism for independent regulation of Ca1+-dependent processes in this cellular compartment.
Abstract: Nuclear calcium (Ca2+) regulates a number of important cellular processes, including gene transcription, growth, and apoptosis. However, it is unclear whether Ca2+ signaling is regulated differently in the nucleus and cytosol. To investigate this possibility, we examined subcellular mechanisms of Ca2+ release in the HepG2 liver cell line. The type II isoform of the inositol 1,4,5-trisphosphate (InsP3) receptor (InsP3R) was expressed to a similar extent in the endoplasmic reticulum and nucleus, whereas the type III InsP3R was concentrated in the endoplasmic reticulum, and the type I isoform was not expressed. Ca2+ signals induced by low InsP3 concentrations started earlier or were larger in the nucleus than in the cytosol, indicating higher sensitivity of nuclear Ca2+ stores for InsP3. Nuclear InsP3R channels were active at lower InsP3 concentrations than InsP3R from cytosol. Enriched expression of type II InsP3R in the nucleus results in greater sensitivity of the nucleus to InsP3, thus providing a mechanism for independent regulation of Ca2+-dependent processes in this cellular compartment.
TL;DR: In this paper, the depressant effect of corn starch, its polysaccharide components (amylose and amylopectin), the monomer glucose and the dimer maltose were studied on hematite and quartz, by means of infrared spectrometry, adsorption isotherms determination and microflotation tests.
TL;DR: In this paper, the authors discuss the specific roles that science has at initial stages of development, pointing to its contributions for the countries' absorptive capability, and specify the role of science for initiating a positive interaction with technological development.
TL;DR: In this article, the authors studied the conservation status of Atlantic forest birds in 43 forest fragments ranging in size from 1 to 384 ha in the Vicosa region of southeastern Brazil and compared data from 15 years of field work with historical records from the region, mainly originating from specimens collected by Joao Moojen during the 1930s.
Abstract: : We studied the conservation status of Atlantic forest birds in 43 forest fragments ranging in size from 1 to 384 ha in the Vicosa region of southeastern Brazil. We compared data from 15 years of field work with historical records from the region, mainly originating from specimens collected by Joao Moojen during the 1930s. We used published studies associated with museum data and current field work to assess the decline of forest birds during the last 70 years and to relate their disappearance to forest fragmentation and destruction. At least 28 bird species have become locally extinct, 43 are critically endangered, and 25 are vulnerable, representing 60.7% of the original forest bird community known to exist in the region. Vulnerability to fragmentation differed among guilds, forest strata, and endemicity status. Birds that feed on fruit and seeds, and those that feed on insects, were more threatened than omnivores and carnivores. Nectarivorous species were less threatened than other guilds. Moreover, terrestrial and understory birds or birds using only one forest stratum also were more likely to have been threatened. Finally, Atlantic forest endemics were more likely to have become extinct than nonendemic species. In general, sensitivity to environmental disturbance at the local level was similar to the predicted vulnerability to regional disturbance derived from the literature. Our results indicate that a serious decline of Atlantic forest birds is underway and that many other species of birds, not previously recognized as threatened, are of conservation concern.
Resumen: Estudiamos el estado de conservacion de aves de bosque atlantico en 43 fragmentos de 1 a 384 ha en la Region Vicosa, al sureste de Brasil. Comparamos datos de 15 anos de trabajo de campo con registros historicos de la region, principalmente de especimenes colectados por Joao Moojen durante la decada de los anos 30. Utilizamos estudios publicados asociados con datos de museo y de trabajo de campo reciente para analizar la disminuicion de aves de bosque durante los ultimos 70 anos y para relacionar su desaparicion con la fragmentacion y destruccion del bosque. Se han extinguido por lo menos 28 especies de aves localmente, 43 estan criticamente en peligro y 25 son vulnerables, lo cual representa el 60,7% de la comunidad de aves de bosque conocida para la region. La vulnerabilidad a la fragmentacion fue diferente entre gremios, estratos de bosque y estado de endemismo. Las aves que se alimentan de frutos y semillas y aquellas que se alimentan de insectos estan mas amenazadas que las omnivoras y carnivoras. Las especies nectarivoras estan menos amenazadas que otros gremios. Mas aun, las aves terrestres y de sotobosque o las que utilizan solo un estrato del bosque tambien tienen mayor probabilidad de estar amenazadas. Finalmente, las aves endemicas al bosque atlantico tienen mayor probabilidad de extincion que las no endemicas. En general, la sensibilidad a la perturbacion ambiental a nivel local fue similar a la vulnerabilidad a la perturbacion regional predicha, derivada de la bibliografia. Nuestros resultados indican que existe una seria declinacion de aves de bosque atlantico y que muchas otras especies de aves, no reconocidas como amenazadas previamente, son de interes para la conservacion.
TL;DR: The systemic and regional hemodynamics effects of ANG-(1−7) were examined in urethane-anesthetized rats as discussed by the authors, and the blood flow distribution (kidneys, skin, mesentery, lungs, spleen, brain, muscle, and adr...
Abstract: The systemic and regional hemodynamics effects of ANG-(1–7) were examined in urethane-anesthetized rats. The blood flow distribution (kidneys, skin, mesentery, lungs, spleen, brain, muscle, and adr...