Operational Characterization of Pressure Regulating Valves.

The functionality of pressure regulating valves (PRVs) is important for proper uniformity and efficiency of irrigation during center pivot irrigation, especially when the center pivot operates on sloping terrain. In practice, the regulated pressure at the PRV outlet is slightly influenced by its inlet pressure, the flow rate through it, and hysteresis effects. The objectives of this work were (a) to evaluate operational characteristics of PRVs based on requirements stated by ISO 10522 (1993) and (b) to model the regulated pressure as a function of inlet pressure and flow rate through the valve considering hysteresis. We carried out tests to evaluate regulation uniformity, regulation curve, hysteresis, and the regulated pressure as function of flow rate and inlet pressure. The following three models of PRVs were evaluated: 10 PSI, 15 PSI, and 20 PSI. For each model, three samples were tested under increasing and decreasing conditions of inlet pressure, within the range from 49.03 to 784.53 kPa, with increments of 49.03 kPa. In addition, flow rates were tested within the range of 0 and 4 m3 h-1. From the gathered data, models to predict outlet pressure as a function of inlet pressure and flow rate were fitted.

Sustained magnetization oscillations in polyaniline-Fe3O4 nanocomposites.

We report experiments with polyaniline-Fe3O4 (PANI-Fe3O4) nanocomposites synthesized under several different conditions. With a reaction carried out at room temperature and assisted by intense ultra-violet (UV) irradiation, we observe sustained oscillations in the magnetization with a period of about 25 min. The oscillations are interpreted as the result of an oscillatory chemical reaction in which part of the Fe(+2) ions of magnetite, Fe3O4, are oxidized by the UV irradiation to form Fe(+3) so that a fraction of the magnetite content transforms into maghemite, γ-Fe2O3. Then, Fe(+3) ions at the nanoparticle surfaces are reduced and transformed back into Fe(+2), when acting as an oxidizing agent for polyaniline in the polymerization process. Since maghemite has smaller magnetization than magnetite, the oscillating chemical reaction results in the oscillatory magnetization. The observations are interpreted with the Lotka-Volterra nonlinear coupled equations with parameters that can be adjusted to fit very well the experimental data.

Genotoxic effect of a keto-aldehyde produced by thermal degradation of reducing sugars.

Reductone (HOCH2-CO-CHO), a keto-aldehyde formed, in alkaline pH, by thermal degradation of reducing sugars, blocks cellular respiration and macromolecular biosynthesis, inactivates far-UV (254 nm)-irradiated wild-type E. coli cells, and causes DNA strand breaks. So it may be supposed to be an inducer of SOS functions. Indeed, when Salmonella tester strains TA98, TA100 and TA102 were treated with reductone solutions, without metabolization, a mutagenic effect was detected for all of them. Besides, reductone induced lysogenic E. coli cells and cell filamentation, as measured by the Inductest and the SOS Chromotest. So reductone must be considered a genotoxic drug.

Evaluation of potential genotoxicity of stannous chloride: inactivation, filamentation and lysogenic induction of Escherichia coli.

Because of the importance of stannous chloride in various fields of human endeavour, the potential genotoxicity of this reducing agent was evaluated by measurement of either the inactivation or the induction of SOS responses in bacteria. Escherichia coli strains used in this work (wild type, uvrA, recA, lexA and uvrA recA) were treated with stannous chloride; the wild type was found to be the most resistant and the double mutant, the most sensitive strain. As these strains present mutations on specific genes for the repair of DNA, stannous chloride would appear to be capable of inducing and/or producing lesions in DNA and, thus, can be considered to be a potential genotoxic agent. This capability was confirmed by the lysogenic induction of E. coli K12 (lambda) (Inductest) and by microscopic observation of E. coli B filamentation.

Cell-mediated immunity in the acquired immunodeficiency syndrome.

The present study evaluates the in vitro cellular immunity response in cases of suspected Acquired Immunodeficiency Syndrome (AIDS). The immunological features of 111 patients were correlated with those from eleven healthy controls. Patients were divided into three groups: RISK, LAS/ARC and AIDS, using CDC criteria. The AIDS showed leucopenia, lymphopenia, diminished number of T and B lymphocytes, normal number of thermostable E-rosette forming cells (TE), decreased helper-inducer T cell, elevated suppressor-cytotoxic T cell, reversed helper T cell/suppressor T cell ratio and depressed proliferative response using mitogens like phytohemagglutinin (PHA), concanavalin-A (Con-A), pokeweed mitogen (PWM) and purified protein derivative antigen (PPD). These findings confirm a severe deficiency in cellular immunity and permit to establish an immune cellular profile, characteristic of the AIDS patients.

Primary immunodeficiency diseases: a presentation of 6 cases.

The peripheral blood leukocytes of 6 children with clinical data suggestive of primary cellular immunodeficiencies were studied in an attempt to define the cellular basis of these disorders. The phenotype and function of T and B cells were investigated. According to the clinical and laboratory features, the patients were classified as one case of severe combined immunodeficiency (SCID), two of ataxia-telangiectasia (AT), one of Wiskott-Aldrich syndrome (WAS), one of DiGeorge syndrome (DSG), and one of cellular immunodeficiency (CID). The laboratory investigations together with the clinical manifestations permitted a diagnosis of primary immunodeficiency diseases.

Neutropenia in an infant: possible autoimmune etiology.

The present study was undertaken to determine if the serum of a child with severe neutropenia contained antibodies against parental neutrophils. The presence of IgG antibodies to granulocytes from both parents was demonstrated using the indirect immunofluorescence technique. These data suggest an autoimmune etiology for the neutropenia of this patient.

[The nurse--construction of a behavior model, based on the medical discourse at the beginning of the century]. / Enfermeira--a construção de um modelo de comportamento a partir dos discursos médicos do início do século.

The purpose of this study is to trace a parallel between the medical discourse content and the expected and stereotyped nurses behavior at the beginning of the twentieth century. It is a historic-social approach in which authors analysed the speeches used by nurses and physicians at nursing and medicine schools. The analysis of the physicians discourse compared to nurses discourse revealed the formation of a mentality shaped by the medical power that wanted them "holy" and servile.

[Nursing--construction of a model based on the medical discourse]. / Enfermeira--a construção de um modelo a partir do discurso médico.

The purpose is to trace a parallel between the medical discourse contents and the expected and stereotyped nurses behavior at the beginning of the twentieth century. It is a historic-social approach in which was made use of speeches uttered by nurses and physicians at nursing and medicine schools. The analysis of physicians discourse compared to nurses discourse disclose the formation of a mentality shaped and turned docile by the medical power which wanted them holy and servile.

Systematization, distribution and territory of the middle cerebral artery on the brain surface in chinchilla (Chinchilla lanigera).

The aim of the present study was to analyse thirty chinchilla (Chinchilla lanigera) brains, injected with latex, and to systematize and describe the distribution and the vascularization territories of the middle cerebral artery. This long vessel, after it has originated from the terminal branch of the basilar artery, formed the following collateral branches: rostral, caudal and striated (perforating) central branches. After crossing the lateral rhinal sulcus, the middle cerebral artery emitted a sequence of rostral and caudal convex hemispheric cortical collateral branches on the convex surface of the cerebral hemisphere to the frontal, parietal, temporal and occipital lobes. Among the rostral convex hemispheric branches, a trunk was observed, which reached the frontal and parietal lobes and, in a few cases, the occipital lobe. The vascular territory of the chinchilla's middle cerebral artery included, in the cerebral hemisphere basis, the lateral cerebral fossa, the caudal third of the olfactory trigone, the rostral two-thirds of the piriform lobe, the lateral olfactory tract, and most of the convex surface of the cerebral hemisphere, except for a strip between the cerebral longitudinal fissure and the vallecula, which extended from the rostral to the caudal poles bordering the cerebral transverse fissure.

Prevalence of pulmonary hypertension in patients with schistosomal liver fibrosis.

Between the April and July of 2007, patients undergoing treatment for schistosomal liver fibrosis, at a university hospital in north-eastern Brazil, were examined by transthoracic Doppler echocardiography (TTE). The main aim was to determine the prevalence of pulmonary hypertension in the patients. The thorax of each patient who had such hypertension, as indicated by an estimated pulmonary arterial systolic pressure (PASP) in excess of 35 mmHg, was then investigated by contrast-enhanced multidetector-row computed tomography (MDCT). The 84 patients (53 women and 31 men) enrolled in the study had a mean (S.D.) age of 50.06 (12.25) years. Nine (10.7%, with a 95% confidence interval of 5.0%-19.4%) of the patients were found to have pulmonary hypertension, with PASP ranging from 40-126 mmHg, and a median (S.D.) PASP of 58.78 (28.01) mmHg. The contrast-enhanced thoracic MDCT indicated that most of the patients with pulmonary hypertension had a pulmonary artery trunk that was unusually wide (67%) and more than 1.1-fold wider than the ascending aorta (56%), dilatation of the main pulmonary arteries (100%), a segmental artery that, in diameter, was more than 1.1-fold larger than the adjacent bronchi (89%), tapering of the peripheral pulmonary arteries (78%), and cardiac enlargement (78%). No patient suffered pulmonary embolism as a result of the investigations. The prevalence of pulmonary hypertension in the patients with schistosomal liver fibrosis (10.7%) justifies the screening of such patients by TTE.

Near-UV light protection effect against lethality induced by stannous chloride in Escherichia coli.

Stannous chloride (SnCl2) is a reducing agent largely employed in industry and in medical procedures. To evaluate its potential genotoxicity, several Escherichia coli strains were treated with SnCl2 and their survival rates determined. Results showed that the double mutant on specific genes for the repair of deoxyribonucleic acid damage was the most sensitive strain. Simultaneous near-UV illumination inhibited the lethal effect of SnCl2 in the wild type strain. Although the nature of the induced lesions are not known these results indicate the potential genotoxicity of SnCl2.

HTLV-I and HTLV-II infections among HIV-1 seropositive patients in Sao Paulo, Brazil.

To estimate the presence of, and the risk factors for HTLV-I and HTLV-II infections among HIV-1 infected subjects in Sao Paulo, Brazil, a serosurvey was performed in 471 HIV-1 infected patients, including 216 intravenous drug addicts (IVDA), 229 homosexual/bisexual men, and 26 with other risk factors. Serum samples were screened for HTLV seroreactivity by ELISA; reactive samples were analyzed by Western Blot (WB), using whole HTLV-I lysate as antigen. To confirm and discriminate HTLV-I and HTLV-II infections, sera presenting any bands on WB were further analyzed by a WB containing recombinant HTLV-I and HTLV-II proteins (WB 2.3), and by enzyme immunoassays using synthetic peptides specific for envelope proteins (Synth-EIA). In 22 cases, cell samples were available for polymerase chain reaction (PCR) studies. On WB, 114 sera were reactive and, of these, 37 and 25 were concordantly positive on both WB 2.3 and Synth-EIA procedures for HTLV-I and HTLV-II specific antibodies, respectively; 37 specimens were negative on both assays, and 15 gave discordant or indeterminate results. PCR findings confirmed concordant results obtained in the discriminatory serological assays. The prevalence rates of HTLV-I and HTLV-II infections were 15.3% and 11.1% in IVDA, and 0.9% and 0.4% in homosexual/bisexual men, respectively. No case of HTLV-I/HTLV-II co-infection was found.

PIP: HTLV-I is associated with adult T-cell leukemia/lymphoma and a neurological disorder known as HTLV-I-associated myelopathy or tropical spastic paraparesis. HTLV-II was initially isolated from subjects with a T-cell variant of hairy cell leukemia, but its etiological role in that or other diseases is unclear. HTLV infections, like HIV, are transmitted sexually, via blood transfusion and contaminated needles, and from mother to infant. Many reports indicate that HTLVs are present in the same populations at risk for HIV-1, and the cofactorial role of HTLVs in AIDS progression has been suggested by in vitro studies and epidemiological data. The authors report findings from a serosurvey conducted among 216 HIV-seropositive male and female intravenous drug users (IVDU), 229 HIV-seropositive homosexual and bisexual men, and 7 HIV-seropositive men and women who had had multiple transfusions, and 19 HIV-seropositive heterosexual men with multiple partners to estimate the presence of and the risk factors for HTLV-I and HTLV-II infections among HIV-1 infected individuals in Sao Paulo, Brazil. 70.9% of the subjects were classified according to CDC criteria as having AIDS. ELISA, Western blot, and polymerase chain reaction methods were used. The prevalence rates of HTLV-I and HTLV-II infections were 15.3% and 11.1% in IVDUs, and 0.9% and 0.4% in homosexual and bisexual men, respectively. No case of HTLV-I/HTLV-II co-infection was observed.