Impactos das atividades humanas sobre a dinâmica do fósforo no meio ambiente e seus reflexos na saúde pública

O fósforo é um nutriente com fontes finitas e não renováveis, cuja velocidade de exploração é atualmente muito superior às suas taxas de retorno ao seu ciclo natural, sendo que já existem previsões a respeito de um provável colapso nas suas fontes disponíveis e conhecidas, com impactos econômicos, sociais e ambientais graves e irreversíveis. Diante desse cenário, o presente trabalho busca apresentar informações sobre a dinâmica do fósforo no meio ambiente, avaliando os impactos causados pelas atividades humanas e verificando as ações que podem auxiliar na preservação do ciclo do nutriente. Visando contribuir para uma melhor visualização do assunto, foi analisada a evolução dos dados relativos à concentração populacional, número de industriais e extensão das áreas cultivadas em uma bacia hidrográfica, em relação às concentrações de fósforo nos compartimentos água e sedimento, ao longo de 22 anos. Para tanto, utilizou-se o rio Tietê como estudo de caso. Os resultados obtidos indicam que o controle das fontes domésticas, principalmente da quantidade de tripolifosfato de sódio (STPP) utilizada nos detergentes, é de grande importância para melhoria da qualidade das águas, proteção ao meio ambiente e garantia da saúde pública

Toll-like receptor 4 (TLR4) expression in human and murine pancreatic beta-cells affects cell viability and insulin homeostasis

Background: Toll-like receptor 4 (TLR4) is widely recognized as an essential element in the triggering of innate immunity, binding pathogen-associated molecules such as Lipopolysaccharide (LPS), and in initiating a cascade of pro-inflammatory events. Evidence for TLR4 expression in non-immune cells, including pancreatic beta-cells, has been shown, but, the functional role of TLR4 in the physiology of human pancreatic beta-cells is still to be clearly established. We investigated whether TLR4 is present in beta-cells purified from freshly isolated human islets and confirmed the results using MIN6 mouse insulinoma cells, by analyzing the effects of TLR4 expression on cell viability and insulin homeostasis. Results: CD11b positive macrophages were practically absent from isolated human islets obtained from nondiabetic brain-dead donors, and TLR4 mRNA and cell surface expression were restricted to beta-cells. A significant loss of cell viability was observed in these beta-cells indicating a possible relationship with TLR4 expression. Monitoring gene expression in beta-cells exposed for 48h to the prototypical TLR4 ligand LPS showed a concentration-dependent increase in TLR4 and CD14 transcripts and decreased insulin content and secretion. TLR4-positive MIN6 cells were also LPS-responsive, increasing TLR4 and CD14 mRNA levels and decreasing cell viability and insulin content. Conclusions: Taken together, our data indicate a novel function for TLR4 as a molecule capable of altering homeostasis of pancreatic beta-cells.

Visual Feedforward Control in Human Locomotion During Avoidance of Obstacles that Change Size

The purpose of the current study was to understand how visual information about an ongoing change in obstacle size is used during obstacle avoidance for both lead and trail limbs. Participants were required to walk in a dark room and to step over an obstacle edged with a special tape visible in the dark. The obstacle's dimensions were manipulated one step before obstacle clearance by increasing or decreasing its size. Two increasing and two decreasing obstacle conditions were combined with seven control static conditions. Results showed that information about the obstacle's size was acquired and used to modulate trail limb trajectory, but had no effect on lead limb trajectory. The adaptive step was influenced by the time available to acquire and process visual information. In conclusion, visual information about obstacle size acquired during lead limb crossing was used in a feedforward manner to modulate trail limb trajectory.

Evolution of magnetic properties and crystallographic texture in electrical steel with large plastic deformation

Deformation leads to a hardening of steel due to an increase in the density of dislocations and a reduction in their mobility, giving rise to a state of elevated residual stresses in the crystal lattice. In the microstructure, one observes an increase in the contribution of crystalline orientations which are unfavorable to the magnetization, as seen, for example, by a decrease in B(50), the magnetic flux density at a field of 50 A/cm. The present study was carried out with longitudinal strips of fully processed non-oriented (NO) electrical steel, with deformations up to 70% resulting from cold rolling in the longitudinal direction. With increasing plastic deformation, the value of B(50) gradually decreases until it reaches a minimum value, where it remains even for larger deformations. On the other hand, the coercive field H(c) continually increases. Magnetometry results and electron backscatter diffraction results are compared and discussed. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3560895]

Vibration-induced extra torque during electrically-evoked contractions of the human calf muscles

Background: High-frequency trains of electrical stimulation applied over the lower limb muscles can generate forces higher than would be expected from a peripheral mechanism (i.e. by direct activation of motor axons). This phenomenon is presumably originated within the central nervous system by synaptic input from Ia afferents to motoneurons and is consistent with the development of plateau potentials. The first objective of this work was to investigate if vibration (sinusoidal or random) applied to the Achilles tendon is also able to generate large magnitude extra torques in the triceps surae muscle group. The second objective was to verify if the extra torques that were found were accompanied by increases in motoneuron excitability. Methods: Subjects (n = 6) were seated on a chair and the right foot was strapped to a pedal attached to a torque meter. The isometric ankle torque was measured in response to different patterns of coupled electrical (20-Hz, rectangular 1-ms pulses) and mechanical stimuli (either 100-Hz sinusoid or gaussian white noise) applied to the triceps surae muscle group. In an additional investigation, M(max) and F-waves were elicited at different times before or after the vibratory stimulation. Results: The vibratory bursts could generate substantial self-sustained extra torques, either with or without the background 20-Hz electrical stimulation applied simultaneously with the vibration. The extra torque generation was accompanied by increased motoneuron excitability, since an increase in the peak-to-peak amplitude of soleus F waves was observed. The delivery of electrical stimulation following the vibration was essential to keep the maintained extra torques and increased F-waves. Conclusions: These results show that vibratory stimuli applied with a background electrical stimulation generate considerable force levels (up to about 50% MVC) due to the spinal recruitment of motoneurons. The association of vibration and electrical stimulation could be beneficial for many therapeutic interventions and vibration-based exercise programs. The command for the vibration-induced extra torques presumably activates spinal motoneurons following the size principle, which is a desirable feature for stimulation paradigms.

Prevalence of Human T-Cell Lymphotropic Virus (HTLV-1/2) in Individuals from Public Health Centers in Mozambique

The prevalence of human T-cell lymphotropic viruses types 1 and 2 (HTLV-1/2) in Mozambique is not known. The present study examined blood samples from 208, 226, and 318 individuals from Northern, Central, and Southern Mozambique, respectively, of all socioeconomic and demographic strata attending public health centers in Mozambique for HTLV-1/2-specific antibodies. Serum samples were assessed for HIV- and HTLV-1/2-specific antibodies by using enzyme immunoassays, and infections with HTLV-1 and -2 were confirmed by using Western blot. An overall HTLV-1/2 prevalence of 2.3% (2.9% in female and 1.1% in male subjects) was observed, and the prevalence of infection increased with age. Regional variation in the prevalence of HIV and HTLV-1/2 was observed; 32.2%, 65.5%, and 44% of individuals tested HIV positive in Northern, Central, and Southern Mozambique, respectively, and 2.4%, 3.9%, and 0.9% tested HTLV-1/2 positive in the same regions. HTLV-1 infection was confirmed in these individuals. No association between HTLV-1 infection and socio-demographic variables or HIV status was detected, although the low number of HTLV-1-positive cases did not allow robust statistical analyses. The results obtained suggest different risk factors and epidemiologic correlates of HIV and HTLV-1 transmission in Mozambique. Furthermore, our results suggested that North and Central Mozambique should be considered endemic regions for HTLV-1 infection. As no cases of HTLV-2 were detected, HTLV-2 appears to have not been introduced into Mozambique.

Sub-telomere directed gene expression during initiation of invasive aspergillosis

Aspergillus fumigatus is a common mould whose spores are a component of the normal airborne flora. Immune dysfunction permits developmental growth of inhaled spores in the human lung causing aspergillosis, a significant threat to human health in the form of allergic, and life-threatening invasive infections. The success of A. fumigatus as a pathogen is unique among close phylogenetic relatives and is poorly characterised at the molecular level. Recent genome sequencing of several Aspergillus species provides an exceptional opportunity to analyse fungal virulence attributes within a genomic and evolutionary context. To identify genes preferentially expressed during adaptation to the mammalian host niche, we generated multiple gene expression profiles from minute samplings of A. fumigatus germlings during initiation of murine infection. They reveal a highly co-ordinated A. fumigatus gene expression programme, governing metabolic and physiological adaptation, which allows the organism to prosper within the mammalian niche. As functions of phylogenetic conservation and genetic locus, 28% and 30%, respectively, of the A. fumigatus subtelomeric and lineage-specific gene repertoires are induced relative to laboratory culture, and physically clustered genes including loci directing pseurotin, gliotoxin and siderophore biosyntheses are a prominent feature. Locationally biased A. fumigatus gene expression is not prompted by in vitro iron limitation, acid, alkaline, anaerobic or oxidative stress. However, subtelomeric gene expression is favoured following ex vivo neutrophil exposure and in comparative analyses of richly and poorly nourished laboratory cultured germlings. We found remarkable concordance between the A. fumigatus host-adaptation transcriptome and those resulting from in vitro iron depletion, alkaline shift, nitrogen starvation and loss of the methyltransferase LaeA. This first transcriptional snapshot of a fungal genome during initiation of mammalian infection provides the global perspective required to direct much-needed diagnostic and therapeutic strategies and reveals genome organisation and subtelomeric diversity as potential driving forces in the evolution of pathogenicity in the genus Aspergillus.

Transcriptional profiling reveals the expression of novel genes in response to various stimuli in the human dermatophyte Trichophyton rubrum

Background: Cutaneous mycoses are common human infections among healthy and immunocompromised hosts, and the anthropophilic fungus Trichophyton rubrum is the most prevalent microorganism isolated from such clinical cases worldwide. The aim of this study was to determine the transcriptional profile of T. rubrum exposed to various stimuli in order to obtain insights into the responses of this pathogen to different environmental challenges. Therefore, we generated an expressed sequence tag (EST) collection by constructing one cDNA library and nine suppression subtractive hybridization libraries. Results: The 1388 unigenes identified in this study were functionally classified based on the Munich Information Center for Protein Sequences (MIPS) categories. The identified proteins were involved in transcriptional regulation, cellular defense and stress, protein degradation, signaling, transport, and secretion, among other functions. Analysis of these unigenes revealed 575 T. rubrum sequences that had not been previously deposited in public databases. Conclusion: In this study, we identified novel T. rubrum genes that will be useful for ORF prediction in genome sequencing and facilitating functional genome analysis. Annotation of these expressed genes revealed metabolic adaptations of T. rubrum to carbon sources, ambient pH shifts, and various antifungal drugs used in medical practice. Furthermore, challenging T. rubrum with cytotoxic drugs and ambient pH shifts extended our understanding of the molecular events possibly involved in the infectious process and resistance to antifungal drugs.

State-of-the-Art and Future Directions for Green Human Resource Management: Introduction to the Special Issue

The topic of environmental sustainability is generating increased concern among business executives, governments, consumers, and management scholars. As these stakeholders struggle with the challenges and opportunities presented by an array of environmental issues, HRM scholars and practitioners alike have been relatively slow to engage in the ongoing discussions and debates. Through this special issue on Green FIRM, we seek to stimulate the field of HRM to expand its role in the pursuit of environmentally sustainable business. In this introduction to the special issue, we first provide an overview of the articles that appear in the special issue. Next we present a detailed discussion of research questions that arise from a consideration of several functional HRM practices, including performance management; training, development, and learning; compensation and rewards; and organizational culture. We conclude by describing opportunities for research at the intersection of strategic HRM and environmental management. If pursued with vigor, research addressing this extensive agenda could begin to establish a healthy field of Green FIRM scholarship.

The four hexamerin genes in the honey bee: structure, molecular evolution and function deduced from expression patterns in queens, workers and drones

Background: Hexamerins are hemocyanin-derived proteins that have lost the ability to bind copper ions and transport oxygen; instead, they became storage proteins. The current study aimed to broaden our knowledge on the hexamerin genes found in the honey bee genome by exploring their structural characteristics, expression profiles, evolution, and functions in the life cycle of workers, drones and queens. Results: The hexamerin genes of the honey bee (hex 70a, hex 70b, hex 70c and hex 110) diverge considerably in structure, so that the overall amino acid identity shared among their deduced protein subunits varies from 30 to 42%. Bioinformatics search for motifs in the respective upstream control regions (UCRs) revealed six overrepresented motifs including a potential binding site for Ultraspiracle (Usp), a target of juvenile hormone (JH). The expression of these genes was induced by topical application of JH on worker larvae. The four genes are highly transcribed by the larval fat body, although with significant differences in transcript levels, but only hex 110 and hex 70a are re-induced in the adult fat body in a caste-and sex-specific fashion, workers showing the highest expression. Transcripts for hex 110, hex 70a and hex70b were detected in developing ovaries and testes, and hex 110 was highly transcribed in the ovaries of egg-laying queens. A phylogenetic analysis revealed that HEX 110 is located at the most basal position among the holometabola hexamerins, and like HEX 70a and HEX 70c, it shares potential orthology relationship with hexamerins from other hymenopteran species. Conclusions: Striking differences were found in the structure and developmental expression of the four hexamerin genes in the honey bee. The presence of a potential binding site for Usp in the respective 5' UCRs, and the results of experiments on JH level manipulation in vivo support the hypothesis of regulation by JH. Transcript levels and patterns in the fat body and gonads suggest that, in addition to their primary role in supplying amino acids for metamorphosis, hexamerins serve as storage proteins for gonad development, egg production, and to support foraging activity. A phylogenetic analysis including the four deduced hexamerins and related proteins revealed a complex pattern of evolution, with independent radiation in insect orders.

A molecular phylogeny and the evolution of nest architecture and behavior in Trigona s.s. (Hymenoptera : Apidae : Meliponini)

Stingless bees exhibit extraordinary variation in nest architecture within and among species. To test for phylogenetic association of behavioral traits for species of the Neotropical stingless bee genus Trigona s.s., a phylogenetic hypothesis was generated by combining sequence data of 24 taxa from one mitochondrial (16S rRNA) and four nuclear gene fragments (long-wavelength rhodopsin copy 1 (opsin), elongation factor-1 alpha copy F2, arginine kinase, and 28S rRNA). Fifteen characteristics of the nest architecture were coded and tested for phylogenetic association. Several characters have significant phylogenetic signal, including type of nesting substrate, nest construction material, and hemipterophily, the tending of hemipteroid insects in exchange for sugar excretions. Phylogenetic independent habits encountered in Trigona s.s. include coprophily and necrophagy.

ProbFAST: Probabilistic Functional Analysis System Tool

Background: The post-genomic era has brought new challenges regarding the understanding of the organization and function of the human genome. Many of these challenges are centered on the meaning of differential gene regulation under distinct biological conditions and can be performed by analyzing the Multiple Differential Expression (MDE) of genes associated with normal and abnormal biological processes. Currently MDE analyses are limited to usual methods of differential expression initially designed for paired analysis. Results: We proposed a web platform named ProbFAST for MDE analysis which uses Bayesian inference to identify key genes that are intuitively prioritized by means of probabilities. A simulated study revealed that our method gives a better performance when compared to other approaches and when applied to public expression data, we demonstrated its flexibility to obtain relevant genes biologically associated with normal and abnormal biological processes. Conclusions: ProbFAST is a free accessible web-based application that enables MDE analysis on a global scale. It offers an efficient methodological approach for MDE analysis of a set of genes that are turned on and off related to functional information during the evolution of a tumor or tissue differentiation. ProbFAST server can be accessed at http://gdm.fmrp.usp.br/probfast.

Time-resolved fluorescence spectroscopy of white-spot caries in human enamel

The objective is to differentiate noncavitated caries enamel through time-resolved fluorescence and to find excitation and emission parameters that can be applied in future clinical practice for detection of caries lesions that are not clearly visible to the professional. Sixteen human teeth with noncavitiated white-spot caries were selected for this work. Fluorescence intensity decay was measured by using an apparatus based on the time-correlated single-photon counting method. An optical fiber bundle was employed for sample excitation (440 nm), and the fluorescence collected by the same bundle (500 nm) was registered. The average lifetime for sound enamel was 7: 93 +/- 0: 09, 2: 46 +/- 0: 04, and 0: 51 +/- 0: 02 ns, whereas for the carious enamel the lifetimes were 4: 84 +/- 0: 06, 1: 35 +/- 0: 02, and 0: 16 +/- 0: 01 ns. It was concluded that it is possible to differentiate between carious and sound regions by time-resolved fluorescence and that, although the origin of enamel fluorescence is still uncertain, the lifetime values seem to be typical of fluorophores like collagen I. (C) 2010 Optical Society of America

The non-equilibrium nature of culinary evolution

Food is an essential part of civilization, with a scope that ranges from the biological to the economic and cultural levels. Here, we study the statistics of ingredients and recipes taken from Brazilian, British, French and Medieval cookery books. We find universal distributions with scale invariant behaviour. We propose a copy-mutate process to model culinary evolution that fits our empirical data very well. We find a cultural 'founder effect' produced by the non-equilibrium dynamics of the model. Both the invariant and idiosyncratic aspects of culture are accounted for by our model, which may have applications in other kinds of evolutionary processes.

High Prevalence of Side Effects After Recombinant Human Thyrotropin-Stimulated Radioiodine Treatment with 30 mCi in Patients with Multinodular Goiter and Subclinical/Clinical Hyperthyroidism

Background: Treatment of multinodular goiters (MNGs) is highly controversial. Radioiodine (RAI) therapy is a nonsurgical alternative for the elderly who decline surgery. Recently, recombinant human thyrotropin (rhTSH) has been used to augment RAI uptake and distribution. In this study, we determined the outcome of 30 mCi RAI preceded by rhTSH (0.1 mg) in euthyroid (EU) and hyperthyroid (subclinical/clinical) patients with large MNGs. Methods: This was a prospective cohort study. Forty-two patients (age, 43-80 years) with MNGs were treated with 30 mCi RAI after stimulation with 0.1 mg of rhTSH. Patients were divided into three groups, according to thyroid function: EU (n = 18), subclinically hyperthyroid (SC-H, n = 18), and clinically hyperthyroid (C-H, n = 6). All patients underwent a 90-day low-iodine diet before treatment, and those with clinical hyperthyroidism received methimazole 10 mg daily for 30 days. Serum TSH, free thyroxine (FT4), total triiodothyronine (TT3), and thyroglobulin were measured at baseline and at 24, 48, 72, 168 hours, and 1, 3, 6, 9, 12, 18, 24, and 36 months after therapy. Thyroid volume was assessed by computed tomography at baseline and every 6 months. Results: Patients had high iodine urinary excretion (308 +/- 108 mu g I/L) at baseline. TSH levels at baseline were within the normal range (1.5 +/- 0.7 mu U/mL) in the EU group and suppressed (< 0.3 mu U/mL) in the SC-H and C-H groups. After rhTSH, serum TSH peaked at 24 hours reaching 12.4 +/- 5.85 mu U/mL. After RAI administration, patients in both hyperthyroid groups had a higher increase in FT4 and TT3 compared with those in the EU group (p < 0.001). Thyroglobulin levels increased equally in all three groups until day 7. Thyroid volume decreased significantly in all patients. Side effects were more common in the SC-H and C-H groups (31.4% and 60.4%, respectively) compared with EU patients (17.8%). Permanent hypothyroidism was more prevalent in the EU group (50%) compared with the SC-H (11%) and C-H (16.6%) groups. Conclusions: Patients with MNG may have subclinical and clinical nonautoimmune iodine-induced hyperthyroidism. Despite a low-iodine diet and therapy with methimazole, hyperthyroid patients have a significantly higher increase in FT4 and TT3 levels after RAI ablation. This can lead to important side effects related mostly to the cardiac system. We strongly advise that patients with SC-H and C-H be adequately treated with methimazole and low-iodine diet aiming to normalize their hyperthyroid condition before rhTSH-stimulated treatment with RAI.