AMMONIA LOSSES ESTIMATED BY AN OPEN COLLECTOR FROM UREA APPLIED TO SUGARCANE STRAW

The quantification of ammonia (NH3) losses from sugarcane straw fertilized with urea can be performed with collectors that recover the NH3 in acid-treated absorbers. Thus, the use of an open NH3 collector with a polytetrafluoroethylene (PTFE)-wrapped absorber is an interesting option since its cost is low, handling easy and microclimatic conditions irrelevant. The aim of this study was to evaluate the efficiency of an open collector for quantifying NH3-N volatilized from urea applied over the sugarcane straw. The experiment was carried out in a sugarcane field located near Piracicaba, Sao Paulo, Brazil. The NH3-N losses were estimated using a semi-open static collector calibrated with N-15 (reference method) and an open collector with an absorber wrapped in PTFE film. Urea was applied to the soil surface in treatments corresponding to rates of 50, 100, 150 and 200 kg ha(-1) N. Applying urea-N fertilizer on sugarcane straw resulted in losses NH3-N up to 24 % of the applied rate. The amount of volatile NH3-N measured in the open and the semi-open static collector did not differ. The effectiveness of the collection system varied non-linearly, with an average value of 58.4 % for the range of 100 to 200 kg ha(-1) of urea-N. The open collector showed significant potential for use; however, further research is needed to verify the suitability of the proposed method.

Ammonia losses estimated by an open collector from urea applied to sugarcane straw

The quantification of ammonia (NH3) losses from sugarcane straw fertilized with urea can be performed with collectors that recover the NH3 in acid-treated absorbers. Thus, the use of an open NH3 collector with a polytetrafluoroethylene (PTFE)-wrapped absorber is an interesting option since its cost is low, handling easy and microclimatic conditions irrelevant. The aim of this study was to evaluate the efficiency of an open collector for quantifying NH3-N volatilized from urea applied over the sugarcane straw. The experiment was carried out in a sugarcane field located near Piracicaba, São Paulo, Brazil. The NH3-N losses were estimated using a semi-open static collector calibrated with 15N (reference method) and an open collector with an absorber wrapped in PTFE film. Urea was applied to the soil surface in treatments corresponding to rates of 50, 100, 150 and 200 kg ha-1 N. Applying urea-N fertilizer on sugarcane straw resulted in losses NH3-N up to 24 % of the applied rate. The amount of volatile NH3-N measured in the open and the semi-open static collector did not differ. The effectiveness of the collection system varied non-linearly, with an average value of 58.4 % for the range of 100 to 200 kg ha-1 of urea-N. The open collector showed significant potential for use; however, further research is needed to verify the suitability of the proposed method.

Validation of models for predicting milk urea nitrogen concentrations, estimating dry matter intake by the NRC (2001)

The objective of this study was to validate three different models for predicting milk urea nitrogen using field conditions, attempting to evaluate the nutritional adequacy diets for dairy cows and prediction of nitrogen excreted to the environment. Observations (4,749) from 855 cows were used. Milk yield, body weight (BW), days in milk and parity were recorded on the milk sampling days. Milk was sampled monthly, for analysis of milk urea nitrogen (MUN), fat, protein, lactose and total solids concentration and somatic cells count. Individual dry matter intake was estimated using the NRC (2001). The three models studied were derived from a first one to predict urinary nitrogen (UN). Model 1 was MUN = UN/12.54, model 2 was MUN = UN/17.6 and model 3 was MUN = UN/(0.0259 × BW), adjusted by body weight effect. To evaluate models, they were tested for accuracy, precision and robustness. Despite being more accurate (mean bias = 0.94 mg/dL), model 2 was less precise (residual error = 4.50 mg/dL) than model 3 (mean bias = 1.41 and residual error = 4.11 mg/dL), while model 1 was the least accurate (mean bias = 6.94 mg/dL) and the least precise (residual error = 5.40 mg/dL). They were not robust, because they were influenced by almost all the variables studied. The three models for predicting milk urea nitrogen were different with respect to accuracy, precision and robustness.

Revised Diagnostic Criteria for Vogt-Koyanagi-Harada Disease: Considerations on the Different Disease Categories

PURPOSE: To evalulate the applicability of the Revised Diagnostic Criteria for Vogt-Koyanagi-Harada (VKH) disease to Brazilian patients and to verify the association between different disease categories, clinical parameters, and the presence of HLA-DRB1*0405. DESIGN: A retrospective observational case series. METHODS: Medical charts of 67 patients (10 to 64 years in age; 12 men and 55 women), from the Uveitis Service, Hospital das Clinicas, University of Sao Paulo School of Medicine (HCFMUSP), Sao Paulo, Brazil were reviewed. Patients, previously diagnosed with VKH disease using criteria proposed by the American Uveitis Society, underwent retrospective classification based on the Revised Diagnostic Criteria. The degree of concordance was assessed. At presentation, 46 patients (69%) were in the early phase. In this group, the mean time from disease onset to treatment was 15 days (range, one to 30 days). Forty-eight patients (72%) were typed for HLA-DRB1*0405 by polymerase chain reaction-sequence specific primer and polymerase chain reaction,sequence, specific oligonucleotides primer. Disease categories, phase at initial presentation, and ocular complications were analyzed. RESULTS: There was a 100% of concordance between the two criteria. Disease was classified as complete in 10 patients (15%), incomplete in 37 patients (55%), and probable in 20 patients (30%). In each group, respectively, 90%, 76%, and 45% were in the early phase at presentation (P = .017). There was no association between disease categories, the presence of HLA-DRB1*0405, and clinical parameters. CONCLUSION. The Revised Diagnostic Criteria proved useful for diagnosis of VKH disease in Brazilian patients. The present retrospective study did not find any association between disease category and severity parameters. To better understand the relevance of disease categories, a minimum follow-up period to categorize patients should be included in future prospective studies. (Am J Ophthalmol 2009;147:339-345. (C) 2009 by Elsevier Inc. All rights reserved.)

NONSPECIFIC INFECTIOUS DISEASES IN PREHISTORIC SAN PEDRO DE ATACAMA, NORTHERN CHILE

The region of San Pedro de Atacama, Northern Chile, has undergone several cultural and social changes after humans settled in Atacama Desert around 500 BC. The Atacameno people experienced the highest degree of social and cultural changes between 400 and 900 AD when they were assimilated into the Tiwanaku trade and political web that influenced most of the Central-Southern Andes. Under the influence of Tiwanaku, San Pedro de Atacama experienced its greatest economic development. Prior analyses of local human skeletal remains have shown a significant increase in the stature of the local population during the same period. In this paper, we investigate the impact of the Tiwanaku influence on the local epidemiological profile using the incidence of periostitis and osteomyelitis as indicators of biological stress. Surprisingly, the best epidemiological condition occurred during the final phase of influence of Tiwanaku (910-960 AD), and not during the apex influence (480-920 AD), as expected by the archaeological context. We suggest that population growth and aggregation may have counteracted the benefits of improved nutrition during the peak Tiwanaku influence. A severe drought occurred between 1,100 and 1,400 AD in Northern Chile. This could also explain the marked increase of bone infections in the post-Tiwanaku period (920-1,240 AD).

A New Species of Fissurella from Sao Pedro e Sao Paulo Archipelago, Brazil (Vetigastropoda, Fissurellidae)

Fissurella mesoatlantica n. sp. is endemic to the Saint Peter and Saint Paul Archipelago, Brazil, located approximately in the middle Atlantic (00 degrees 55N. 29 degrees 20W). The species is very similar to F. clenchi from the mainland Brazilian coast, differing in having a taller. more richly sculptured shell and by anatomical details. such its the papillae of mantle border and epipodial tentacles. A complete anatomical description is included.

On the stability of the extracellular hemoglobin of Glossoscolex paulistus, in two iron oxidation states, in the presence of urea

The stability of the Glossoscolex paulistus hemoglobin (HbGp), in two iron oxidation states (and three forms), as monitored by optical absorption, fluorescence emission and circular dichroism (CD) spectroscopies, in the presence of the chaotropic agent urea, is studied. HbGp oligomeric dissociation, denaturation and iron oxidation are observed. CD data show that the cyanomet-HbGp is more stable than the oxy-form. Oxy- and cyanomet-HbGp show good fits on the basis of a two state model with critical urea concentrations at 220-222 nm of 5.1 +/- 0.2 and 6.1 +/- 0.1 mol/L, respectively. The three-state model was able to reveal a subtle second transition at lower urea concentration (1.0-2.0 mol/L) associated to partial oligomeric dissociation. The intermediate state for oxy- and cyanomet-HbGp is very similar to the native state. For met-HbGp, a different equilibrium, in the presence of urea, is observed. A sharp transition at 1.95 +/- 0.05 mol/L of denaturant is observed, associated to oligomeric dissociation and hemichrome formation. In this case, analysis by a three-state model reveals the great similarity between the intermediate and the unfolded states. Analysis of spectroscopic data, by two-state and three-state models, reveals consistency of obtained thermodynamic parameters for HbGp urea denaturation. (C) 2012 Elsevier Inc. All rights reserved.

Kinetic and thermodynamic investigation of Arthrospira (Spirulina) platensis fed-batch cultivation in a tubular photobioreactor using urea as nitrogen source

BACKGROUND: Fed-batch culture allows the cultivation of Arthrospira platensis using urea as nitrogen source. Tubular photobioreactors substantially increase cell growth, but the successful use of this cheap nitrogen source requires a knowledge of the kinetic and thermodynamic parameters of the process. This work aims at identifying the effect of two independent variables, temperature (T) and urea daily molar flow-rate (U), on cell growth, biomass composition and thermodynamic parameters involved in this photosynthetic cultivation. RESULTS: The optimal values obtained were T = 32 degrees C and U = 1.16 mmol L-1 d-1, under which the maximum cell concentration was 4186 +/- 39 mg L-1, cell productivity 541 +/- 5 mg L-1 d-1 and yield of biomass on nitrogen 14.3 +/- 0.1 mg mg-1. Applying an Arrhenius-type approach, the thermodynamic parameters of growth (?H* = 98.2 kJ mol-1; ?S* = - 0.020 kJ mol-1 K-1; ?G* = 104.1 kJ mol-1) and its thermal inactivation (Delta H-D(0) =168.9 kJ mol-1; Delta S-D(0) = 0.459 kJ mol-1 K-1; Delta G(D)(0) =31.98 kJ mol-1) were estimated. CONCLUSIONS: To maximize cell growth T and U were simultaneously optimized. Biomass lipid content was not influenced by the experimental conditions, while protein content was dependent on both independent variables. Using urea as nitrogen source prevented the inhibitory effect already observed with ammonium salts. Copyright (c) 2012 Society of Chemical Industry

CHARACTERIZATION OF THE MICRO-SITE CONDITIONS FROM RESTORED AREAS WITH DIFFERENT AGES

Regeneration microsites are characterized by diverse combinations of attributes which assure the best conditions for seed germination and seedling establishment. By understanding these attributes, we can contribute to determining better management methodologies for reestablishing ecological process in sites under restoration. Thus, we sought to characterize and differentiate the micro-site conditions of restoration plantings to indentify likely physical-chemical limitations for the establishment of native tree species in the forest understory. This study was carried out in reforestation plantings with different ages (10, 22 and 55 years). The physical-chemical characterization of the micro-site of regeneration of the study areas was carried out by evaluating the soil compression level, porosity, humidity, organic matter and nutrients content and granulometry, as well as litter dry mass and canopy cover. An increase on the canopy cover and soil porosity, humidity, clay and organic matter content were observed in the oldest restored areas, as well as a decrease in soil compression. Thus, these findings demonstrated that the evaluated microsite properties are in process of restoration. Therefore, microsite conditions for seedling establishment become even more similar to reference ecosystems as restoration planting evolve.

Tailoring the structure, composition, optical properties and catalytic activity of Ag-Au nanoparticles by the galvanic replacement reaction

This Letter reports on the synthesis of Ag-Au nanoparticles (NPs) with controlled structures and compositions via a galvanic replacement reaction between Ag NPs and AuCl4(aq)- followed by the investigation of their optical and catalytic properties. Our results showed the formation of porous walls, hollow interiors and increased Au content in the Ag-Au NPs as the volume of AuCl4(aq)- employed in the reaction was increased. These variations led to a red shift and broadening of the SPR peaks and an increase of up to 10.9-folds in the catalytic activity towards the reduction of 4-nitrophenol relative to Ag NPs. (C) 2012 Elsevier B.V. All rights reserved.

Metabolic assessment of elderly men with urolithiasis

OBJECTIVE: To assess the presence of metabolic disorders in elderly men with urolithiasis. METHODS: We performed a case-control study. The inclusion criteria were as follows: (1) men older than 60 years of age and either (2) antecedent renal colic or an incidental diagnosis of urinary lithiasis after age 60 (case arm) or (3) no antecedent renal colic or incidental diagnosis of urolithiasis (control arm). Each individual underwent an interview, and those who were selected underwent all clinical protocol examinations: serum levels of total and ionized calcium, uric acid, phosphorus, glucose, urea, creatinine and parathyroid hormone, urine culture, and analysis of 24-hour urine samples (levels of calcium, citrate, creatinine, uric acid and sodium, pH and urine volume). Each case arm patient underwent two complete metabolic urinary investigations, whereas each control arm individual underwent one examination. ClinicalTrials.gov: NCT01246531. RESULTS: A total of 51 subjects completed the clinical investigation: 25 in the case arm and 26 in the control arm. In total, 56% of the case arm patients had hypocitraturia (vs. 15.4% in the control arm; p = 0.002). Hypernatriuria was detected in 64% of the case arm patients and in 30.8% of the controls (p = 0.017). CONCLUSION: Hypocitraturia and hypernatriuria are the main metabolic disorders in elderly men with urolithiasis.

Distinct mechanisms underlie adaptation of proximal tubule Na+/H+ exchanger isoform 3 in response to chronic metabolic and respiratory acidosis

The Na+/H+ exchanger isoform 3 (NHE3) is essential for HCO3- reabsorption in renal proximal tubules. The expression and function of NHE3 must adapt to acid-base conditions. The goal of this study was to elucidate the mechanisms responsible for higher proton secretion in proximal tubules during acidosis and to evaluate whether there are differences between metabolic and respiratory acidosis with regard to NHE3 modulation and, if so, to identify the relevant parameters that may trigger these distinct adaptive responses. We achieved metabolic acidosis by lowering HCO3- concentration in the cell culture medium and respiratory acidosis by increasing CO2 tension in the incubator chamber. We found that cell-surface NHE3 expression was increased in response to both forms of acidosis. Mild (pH 7.21 +/- 0.02) and severe (6.95 +/- 0.07) metabolic acidosis increased mRNA levels, at least in part due to up-regulation of transcription, whilst mild (7.11 +/- 0.03) and severe (6.86 +/- 0.01) respiratory acidosis did not up-regulate NHE3 expression. Analyses of the Nhe3 promoter region suggested that the regulatory elements sensitive to metabolic acidosis are located between -466 and -153 bp, where two consensus binding sites for SP1, a transcription factor up-regulated in metabolic acidosis, were localised. We conclude that metabolic acidosis induces Nhe3 promoter activation, which results in higher mRNA and total protein level. At the plasma membrane surface, NHE3 expression was increased in metabolic and respiratory acidosis alike, suggesting that low pH is responsible for NHE3 displacement to the cell surface.

Arthrospira platensis biomass with high protein content cultivated in continuous process using urea as nitrogen source

Aims: Arthrospira platensis has been studied for single-cell protein production because of its biomass composition and its ability of growing in alternative media. This work evaluated the effects of different dilution rates (D) and urea concentrations (N0) on A.similar to platensis continuous culture, in terms of growth, kinetic parameters, biomass composition and nitrogen removal. Methods and results: Arthrospira platensis was continuously cultivated in a glass-made vertical column photobioreactor agitated with Rushton turbines. There were used different dilution rates (0.040.44 day-1) and urea concentrations (0.5 and 5 mmol l-1). With N0 = 5 mmol l-1, the maximum steady-state biomass concentration was1415 mg l-1, achieved with D = 0.04 day-1, but the highest protein content (71.9%) was obtained by applying D = 0.12 day-1, attaining a protein productivity of 106.41 mg l-1 day-1. Nitrogen removal reached 99% on steady-state conditions. Conclusions: The best results were achieved by applying N0 = 5 mmol l-1; however, urea led to inhibitory conditions at D = 0.16 day-1, inducing the system wash-out. The agitation afforded satisfactory mixture and did not harm the trichomes structure. Significance and Impact of the Study: These results can enhance the basis for the continuous removal of nitrogenous wastewater pollutants using cyanobacteria, with an easily assembled photobioreactor.

Severity of restless legs syndrome is inversely correlated with echogenicity of the substantia nigra in different neurodegenerative movement disorders. A preliminary observation

Objective: Hyperechogenicity of the substantia nigra is a frequent observation on transcranial sonography in Parkinson's disease and Machado-Joseph disease patients. Additionally, restless legs syndrome is a sleep disorder that is also frequently found in both diseases. Autopsy studies have demonstrated increased SN iron content in hyperechogenic substantia nigra. Iron storage is also known to be involved in restless legs syndrome. We formally compared echogenicity of the substantia nigra with restless legs syndrome in Parkinson's disease and Machado-Joseph disease patients. Methods: Transcranial brain sonography was performed in a sample of Parkinson's disease and Machado-Joseph disease patients, and findings then correlated with the presence and severity of restless legs syndrome. Results: There was a continuum of substantia nigra echogenicity among groups (Parkinson's disease versus Machado-Joseph disease versus controls) and sub-groups (Parkinson's disease with and without restless legs syndrome versus Machado-Joseph disease with and without restless legs syndrome) as well as a statistically significant negative correlation between restless legs syndrome severity and substantia nigra echogenicity (p<0.001). Conclusions: These preliminary observations demonstrate that the severity of RLS may be influenced by nigral iron load reflected by substantia nigra echogenicity in different neurodegenerative movement disorders. (C) 2012 Elsevier B.V. All rights reserved.

Urea-Based Synthesis of Zinc Oxide Nanostructures at Low Temperature

The preparation of nanometer-sized structures of zinc oxide (ZnO) from zinc acetate and urea as raw materials was performed using conventional water bath heating and a microwave hydrothermal (MH) method in an aqueous solution. The oxide formation is controlled by decomposition of the added urea in the sealed autoclave. The influence of urea and the synthesis method on the final product formation are discussed. Broadband photoluminescence (PL) behavior in visible-range spectra was observed with a maximum peak centered in the green region which was attributed to different defects and the structural changes involved with ZnO crystals which were produced during the nucleation process.