A bench arc-furnace facility for fullerene and single-wall nanotubes synthesis

A metallic-sample arc-furnace was modified to synthesize fullerenes and nanotubes. The (reversible) changes and the process for producing single-wall nanotubes (SWNTs) are described.

Síntese de nanotubos de carbono de parede simples por sublimação de grafite em atmosfera de hélio

Macroscopic samples of fullerene nanostructures are obtained in a modified arc furnace using the electric arc method with a Helium atmosphere at low pressures. High purity graphite rods are used as electrodes but, when drilled and the orifices filled with powders of transition metals (Fe, Co, Ni) acting as catalysts, the resulting particles are carbon nanostructures of the fullerene family, known as Single Wall Nanotubes (SWNTs). They have typical diameters of 1.4 nm, lengths up to tenths of microns and they are arranged together in bundles containing several SWNTs. Those samples are observed and analyzed using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques.

Block of the Mitral-pulmonary Isthmus During Ablation of a Single Left-sided Accessory Pathway Causing Different Patterns of Retrograde Atrial Activation

The case of a 16-year-old patient with atrioventricular tachycardia caused by a single left anterolateral accessory pathway is reported. When the patient underwent radiofrequency ablation, a lesion on the mitral annulus lateral wall produced changes in the retrograde atrial activation pattern determined by that pathway; changes ranged from a delay in depolarization of the annulus posterior portions to full left atrium counterclockwise activation. Such phenomena were probably caused by a block in the isthmus between the annulus and the lower left pulmonary vein ostium. This case illustrates the importance of the mitral-pulmonary isthmus in the process of left atrium activation, an alert to changes induced by its unintentional block during accessory pathway ablation.

Open abdomen management: single institution experience

OBJECTIVE: to evaluate the outcome of abdominal wall integrity of both techniques. METHODS: a retrospective study was carried out at the Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, identifying the patients undergoing temporary abdominal closure (TAC) from January 2005 to December 2011. Data were collected through the review of clinical charts. Inclusion criteria were indication of TAC and survival to definitive abdominal closure. In the post-operative period only a group of three surgeons followed all patients and performed the reoperations. RESULTS: Twenty eightpatients were included. The difference in primary closure rates and mean time for fascial closure did not reach statistical significance (p=0.98 and p=0.23, respectively). CONCLUSION: VAC and Bogota Bag do not differ significantly regarding the outcome of abdominal wall integrity, due to the monitoring of a specific team and the adoption of progressive closure

Soybean growth and yield after single tillage and species mixture of cover plants

The use of cover crops is important for the agricultural crop and soil management in order to improve the system and, consequently, to increase yield. Therefore, the present study analyzed the effect of crop residues of black oat (Avena strigosa Schreb.) (BO) and a cocktail (CO) of BO, forage turnip (Raphanus sativus L.) (FT) and common vetch (Vicia sativa L.) (V) on the emergence speed index (ESI), seedling emergence speed (SES) plant height and soybean yield in different intervals between cover crop desiccation with glyphosate 480 (3 L ha-1) and BRS 232 cultivar sowing. Plots of 5 x 2.5 m with 1 m of border received four treatments with BO cover crops and four with CO as well as a control for each cover crop, at random, with five replications. The plots were desiccated in intervals of 1, 10, 20 and 30 days before soybean seeding. The harvest was manual while yield was adjusted to 13% of moisture content. The experimental design was completely randomized with splitplots and means compared by the Scott and Knott test at 5% of significance. The results showed that CO of cover crops can be recommended for soybean to obtain a more vigorous seedling emergence, from 10 days after cover crop desiccation.

Urease inhibitor (NBPT) and efficiency of single or split application of urea in wheat crop

NBPT (N-(n-butyl) thiophosphoric triamide), a urease inhibitor, has been reported as one of the most promising compounds to maximize urea nitrogen use in agricultural systems. The objective of this study was to evaluate the performance of irrigated wheat fertilized with urea or urea + NBPT as single or split application. The experiment was conducted from June to October 2006 in Viçosa, MG, Brazil. The experimental design followed a 2×2 factorial scheme, in which urea or urea + NBPT were combined with two modes of application: full dose at sowing (60kg ha-1) or split (20kg ha-1 at sowing + 40kg ha-1 as topdressing at tillering), in randomized blocks with ten replications. The split application of nitrogen fertilization does not improve the yield wheat under used conditions. The use of urease inhibitor improves the grain yield of wheat crop when urea is applied in topdressing at tillering, but its use does not promote difference when urea is applied in the furrow at planting.

WHAT IS THE USE OF A SINGLE-CASE STUDY IN MANAGEMENT RESEARCH?

The purpose of this article is to present a defense of the use of single case studies in management research. The defense is necessary because this type of research has been relegated to a secondary role, or even rejected, by many researchers, who consider it unscientific. Evidence of this low status is the fact that most reputable academic journals in management publish few articles based on single-case studies. In this paper, we examine in detail the objections to the use of such cases in management research. We show the efforts made by some researchers to answer these objections and we show quality criteria for research that are alternatives to the criteria used in the so-called "scientific method." Our analysis suggests that a better understanding - by researchers with different methodological preferences - of the arguments for each particular use of the single-case study as a research method would allow a better dialogue between researchers and benefit management research as a whole.

The use of wide-mesh gauze impregnated with lambda-cyhalothrin covering wall openings in huts as a vector control method in Suriname

An alternative vector control method, using lambda-cyhalothrin impregnated wide-mesh gauze covering openings in the walls of the houses was developed in an area in the Eastern part of the interior of Suriname. Experimental hut observations showed that Anopheles darlingi greatly reduced their biting activity (99-100%) during the first 5 months after impregnation. A model assay showed high mortality both of mosquitoes repelled by the gauze as well as of those that succeeded in getting through it. A field application test in 270 huts showed good acceptance by the population and good durability of the applied gauze. After introducing the method in the entire working area, replacing DDT residual housespraying, the malaria prevalence, of 25-37% before application dropped and stabilized at between 5 and 10% within one year. The operational costs were less than those of the previously used DDT housespraying program, due to a 50% reduction in the cost of materials used. The method using widemesh gauze impregnated with lambdacyhalothrin strongly affects the behavior of An. darlingi. It is important to examine the effect of the method on malaria transmission further, since data indirectly obtained suggest substantial positive results.

Validity of self-reported hearing loss in adults: performance of three single questions

OBJECTIVE: To estimate the validity of three single questions used to assess self-reported hearing loss as compared to pure-tone audiometry in an adult population. METHODS: A validity study was performed with a random sub-sample of 188 subjects aged 30 to 65 years, drawn from the fourth wave of a population-based cohort study carried out in Salvador, Northeastern Brazil. Data were collected in household visits using questionnaires. Three questions were used to separately assess self-reported hearing loss: Q1, "Do you feel you have a hearing loss?"; Q2, "In general, would you say your hearing is 'excellent,' 'very good,' 'good,' 'fair,' 'poor'?"; Q3, "Currently, do you think you can hear 'the same as before', 'less than before only in the right ear', 'less than before only in the left ear', 'less than before in both ears'?". Measures of accuracy were estimated through seven measures including Youden index. Responses to each question were compared to the results of pure-tone audiometry to estimate accuracy measures. RESULTS: The estimated sensitivity and specificity were 79.6%, 77.4% for Q1; 66.9%, 85.1% for Q2; and 81.5%, 76.4% for Q3, respectively. The Youden index ranged from 51.9% (Q2) to 57.0% (Q1) and 57.9% (Q3). CONCLUSIONS: Each of all three questions provides responses accurate enough to support their use to assess self-reported hearing loss in epidemiological studies with adult populations when pure-tone audiometry is not feasible.

A single method to stain Malassezia furfur and Corynebacterium minutissimum in scales

A single and practical method to slain Malassezia furfur and Corynebacterium minutissimum in lesions' scales is described. The scales are collected by pressing small pieces of scotch tape (about 4 cm lenght and 2 cm width) onto the lesions and following withdrawl the furfuraceous scales will remain on the glue side. These pieces are then immersed for some minutes in lactophenol-cotton blue stain. Following absorption of the stain the scales are washed in current water to remove the excess of blue stain, dried with filter paper, dehydrated via passage in two bottles containing absolute alcohol and then placed in xylene in a centrifugation tube. The xylene dissolves the scotch tape glue and the scales fall free in the tube. After centrifugation and decantation the scales concentrated on the bottom of the tube are collected with a platinum-loop, placed in Canada balsam on a microscopy slide and closed with a cover slip. The preparations are then ready to be submitted to microscopic examination. Other stains may also be used instead of lactophenol-cotton blue. This method is simple, easily performed, and offers good conditions to study these fungi as well as being useful for the diagnosis of the diseases that they cause.

CONSTITUTIVE MELANIN IN THE CELL WALL OF THE ETIOLOGIC AGENT OF LOBO'S DISEASE

Lobo's disease is a chronic granulomatous disease caused by the obligate pathogenic fungus, whose cell walls contain constitutive melanin. In contrast, melanin does not occur in the cell walls of Paracoccidioides brasiliensis when stained by the Fontana-Masson stain.

Assessment of chloroquine single dose treatment of malaria due to Plasmodium vivax in Brazilian Amazon

Malaria regions of the Amazon basin have been characterized by difficult access and non-compliance of the patients to treatment. In an attempt to assess the schizonticide efficacy of chloroquine in a single dose of 600 mg, the authors realized a double-blind, placebo-controlled trial in 132 outpatients with vivax malaria. Patients were distributed into two groups: group CPLA, given chloroquine 600 mg (single dose) on the first day of treatment, and two doses of placebo on second and third days. Group CHLO, given chloroquine 600 mg on first day and 450 mg on second and third day. Geometric means of the parasite density during the follow-up was similar in both groups. No differences were observed in the parasitological cure between the two groups (p = 0.442). There was clinical and parasitological efficacy in treatment of patients given a single-dose of chloroquine. This suggests that its restricted use could be indicated in remote areas of Brazilian Amazon Region, nevertheless the inadequate response of three patients indicates the need for further studies.