Supercritical fluid extraction for pesticide multiresidue analysis in honey: determination by gas chromatography with electron-capture and mass spectrometry detection

An analytical procedure using supercritical fluid extraction (SFE) and capillary gas chromatography with electron-capture detection was developed to determine simultaneously residues of different pesticides (organochlorine, organophosphorus, organonitrogen and pyrethroid) in honey samples. Fortification experiments were conducted to test conventional extraction (liquid-liquid) and optimize the extraction procedure in SFE by varying the CO2-modifier, temperature, extraction time and pressure. Best efficiency was achieved at 400 bar using acetonitrile as modifier at 90 degreesC. For the clean-up step, Florisil cartridges were used for both methods LLE and SFE. Recoveries for majority of pesticides from fortified samples of honey at fortification level of 0.01-0.10 mg/kg ranged 75-94% from both methods. Limits of detection found were less than 0.01 mg/kg for ECD and confirmation of pesticide identity was performed by gas chromatography-mass spectrometry in selected-ion monitoring mode. The multiresidue methods in real honey samples were applied and the results of developed methods were compared. (C) 2004 Elsevier B.V. All rights reserved.

Multiresidue analysis of pesticides in soil by supercritical fluid extraction/gas chromatography with electron-capture detection and confirmation by gas chromatography-mass spectrometry

The applicability of supercritical fluid extraction (SFE) in pesticide multiresidue analysis (organohalogen, organonitrogen, organophosphorus, and pyrethroid) in soil samples was investigated. Fortification experiments were conducted to test the conventional extraction (solid-liquid) and to optimize the extraction procedure in SFE by varying the CO2 Modifier, temperature, extraction time, and pressure. The best efficiency was achieved at 400 bar using methanol as modifier at 60 degreesC. For the SFE method, C-18 cartridges were used for the cleanup. The analytical screening was performed by gas chromatography equipped with electron-capture detection (ECD). Recoveries for the majority of pesticides from spiked samples of soil at different residence times were 1, 20, and 40 days at the fortification level of 0.04-0.10 mg/kg ranging from 70 to 97% for both methods. The detection limits found were <0.01 mg/kg for ECD, and the confirmation of pesticide identity was performed by gas chromatography-mass spectrometry in a selected-ion monitoring mode. Multiresidue methods were applied in real soil samples, and the results of the methods developed were compared.

A continuously differentiable upwinding scheme for the simulation of fluid flow problems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analysis of the different forms of application and types of cutting fluid used in plunge cylindrical grinding using conventional and superabrasive CBN grinding wheels

The work reported here involved an investigation into the grinding process, one of the last finishing processes carried out on a production line. Although several input parameters are involved in this process, attention today focuses strongly on the form and amount of cutting fluid employed, since these substances may be seriously pernicious to human health and to the environment, and involve high purchasing and maintenance costs when utilized and stored incorrectly. The type and amount of cutting fluid used directly affect some of the main output variables of the grinding process which are analyzed here, such as tangential cutting force, specific grinding energy, acoustic emission, diametrical wear, roughness, residual stress and scanning electron microscopy. To analyze the influence of these variables, an optimised fluid application methodology was developed (involving rounded 5, 4 and 3 turn diameter nozzles and high fluid application pressures) to reduce the amount of fluid used in the grinding process and improve its performance in comparison with the conventional fluid application method (of diffuser nozzles and lower fluid application pressure). To this end, two types of cutting fluid (a 5% synthetic emulsion and neat oil) and two abrasive tools (an aluminium oxide and a superabrasive CBN grinding wheel) were used. The results revealed that, in every situation, the optimised application of cutting fluid significantly improved the efficiency of the process, particularly the combined use of neat oil and CBN grinding wheel. (c) 2005 Elsevier Ltd. All rights reserved.

A sustainable alternative for cooling the machining processes using a refrigerant fluid in recirculation inside the toolholder

This article presents a cooling system for cutting tool in turning based in a toolholder with cooling fluid flowing inside its body being that this fluid must necessarily be able to phase change due to heat generated from machining processes. In this way, the fluid evaporates just under the cutting tool allowing a heat transfer more efficient than if were used a fluid without phase change once the latent heat of evaporation is beneficial for removal heat. Following, the cooling fluid evaporated passes through a condenser located out of the toolholder where it is condensated and returns to the toolholder again and a new cycle is started. In this study, the R-123, a hydrochlorofluorocarbon (HCFC) fluid, was selected for the turning of a Cr-Ni-Nb-Mn-N austenitic steel of hard machinability. The machining tests were carried out under three different machining conditions: dry machining, external cutting fluid (conventional method), and with the toolholder proposed. As result, the developed system allows a surface roughness up to 10% better than dry machining and a tool life close to the conventional method, but 32% superior to dry machining; moreover, there are environmental and economics advantages once the cooling fluid is maintained in a loop circuit.

Detection of antibody to Toxocara vitulorum perieneteric fluid antigens (Pe) in the colostrum and serum of buffalo calves and cows by Western blotting

Toxocara vitulorum, a nematode parasite in the small intestine of cattle and water buffaloes, causes high morbidity and mortality of 1-3 months old buffalo calves. This research evaluated the specific perieneteric antigens (Pe) reactivity of anti-T. vitulorum-Pe antibody (Tv-Pe-Ab) in both immune sera and colostrum from buffalo cows immediately post-partum from buffalo cows. The presence of Tv-Pe-Ab in sera of buffalo newborn calves was also examined at 1 day before and after suckling the colostrum as well as in sera from naturally infected calves at the beginning and peak of the maximum infection and then again during the period of rejection and post-rejection of the parasite. Pe antigens were characterized for Tv-Pe-Ab by SDS-PAGE and Western blot (WB). The SDS-PAGE showed that Pe contained nine protein bands (11, 14, 31, 38, 58, 76, 88,112 and 165 kDa). All Pe bands were recognized by Tv-Pe-Ab in sera and colostrum of buffalo cows. Only the serum antibodies of buffalo calves at 1 day of age after suckling the colostrum and during the beginning of T. vitulorum infection recognized Pe antigen's nine bands. In contrast, serum antibodies from 1-day-old buffalo calves, taken before suckling colostrum, did not react with any protein band. In suckling calves, which reached peak egg output, rejection and post-rejection stages of the infection, serum Tv-Pe-Ab reactivity with lower molecular weight protein bands (11-76 kDa) was lost and only reactivity with the Pe protein bands of higher molecular weight (88, 112 and 165 kDa) remained. (c) 2005 Elsevier B.V. All rights reserved.

New geopolymeric binder based on fluid catalytic cracking catalyst residue (FCC)

This paper provides information about the synthesis and mechanical properties of geopolymers based on fluid catalytic cracking catalyst residue (FCC). FCC was alkali activated with solutions containing different SiO2/Na2O ratios. The microstructure and mechanical properties were analysed by using several instrumental techniques. FCC geopolymers are mechanically stable, yielding compressive strength about 68 MPa when mortars are cured at 65 degrees C during 3 days. The results confirm the viability of producing geopolymers based on FCC. (C) 2012 Elsevier B.V. All rights reserved.

Numerical analysis of refrigerant flow along non-adiabatic capillary tubes using a two-fluid model

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of fluid volume variations on the calculated value of the left ventricular mass measured by echocardiogram in patients submitted to hemodialysis

The left ventricular mass (LVM) measurement is of major importance for renal patients, as ventricular hypertrophy is an important prognostic index. The echo-cardiogram of the ventricular mass is larger before than it is after hemodialysis, which can confuse data interpretation. The aim of this work is to study the influence of alterations in fluid volume on the variations in measurements of ventricular mass observed during the course of a hemodialysis. Sixteen patients with chronic renal insufficiency in hemodialysis were evaluated at the Dialysis Unit of the University Hospital-UNESP, Botucatu, São Paulo State. The left ventricular mass was calculated from echocardiograms taken before and after hemodialysis and simultaneous ultra-filtration (12 patients: UF GROUP) and before and after hemodialysis isovolemic phase with sequential ultra-filtration (10 patients: ISO GROUP). Six of these patients were submitted to measurements of left ventricular mass before and after hemodialysis in both isovolemic and simultaneous ultra-filtration procedures. In the UF group, there was significant reduction in the following parameters before and after dialysis: diastolic diameter from 54.0 +/- 6.0 mm to 45.6 +/- 7.6 mm; left ventricular mass from 342 +/- 114 g to 265 +/- 117 g; and its respective index (IMVE) from 214 +/- 68 g/m(2) to 168 +/- 71 g/m(2). The ISO group showed no statistically significant variation. The behavior of the variables of six patients submitted to both observations confirm these results. In conclusion, the variations in echocardiogram measurements of the left ventricular mass relating to hemodialysis appear to be induced by alterations of the volemic condition.

Hematological and cerebrospinal fluid changes in cattle naturally and experimentally infected with the bovine herpesvirus 5

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of maternal hydration on the increase of amniotic fluid index

The objective of this study was to determine the effect of maternal hydration with oral isotonic solution and water on the amniotic fluid (AF) index of women with normohydramnios. Women with a normal AF index and gestational age between 33 and 36 weeks without maternal complications were randomized into three groups [isotonic solution (Gatorade (R)), water, control]. The isotonic solution and water groups were instructed to drink 1.5 L of the respective solution and the control group was instructed to drink 200 mL water over a period of 2 to 4 h. AF index was measured before and after hydration by Doppler ultrasonography. The investigator performing the AF index measurement was blind to the subject's group. Ninety-nine women completed the study without any adverse maternal effects. The median increase in AF index after hydration was significantly greater for the isotonic solution and water groups than for the control group. There was no significant difference between the isotonic solution and water groups. Hydration with isotonic solution and water caused a 10-fold (95% CI: 2.09-49.89) and 6-fold (95% CI: 1.16-30.95) increase in the chance of a 20% increase of AF index, respectively. Maternal hydration with isotonic solution or water increased the AF index in women with normohydramnios.

Fatty acid composition of mid-trimester amniotic fluid in women of different ethnicities

Objective: To determine whether the fatty acid composition of mid-trimester amniotic fluid differs by ethnicity and pregnancy outcome. Methods: Fatty acid composition was analyzed by gas chromatography in 198 women undergoing amniocentesis at 15-19 weeks gestation. Cytokine levels were determined by ELISA in a subgroup of 52 subjects. Results: The major fatty acids detected were palmitic acid (31.8%) and stearic acid (31.5%). The n-6 polyunsaturated fatty acids (PUFA), linoleic acid (LA, 18: 2) and arachidonic acid (AA, 20: 4), were 11.3%, while the n-3 PUFA fatty acids, alpha linolenic acid (ALA, 18: 3) and docosahexaenoic acid (DHA, 22: 6), were 3.8% of the total. Palmitic acid was a higher percentage in Asians (40.5%) and Whites (34.5%) than in Blacks (22.2%) and Hispanics (23.7%) (p <= 0.0012). Oleic acid (18:1 n-9) was a higher percentage in Blacks (12.2%) and Hispanics (12.1%) than in Whites (9.2%) or Asians (7.5%) (<= 0.0002). LA and AA were higher in Blacks (9.0%, 5.4%) and Hispanics (8.6%, 4.1%) than in Whites (6.1%, 3.7%) and Asians (5.5%, 2.9%) (p <= 0.0002). DHA did not differ among the ethnic groups or according to pregnancy outcome. A reduced palmitic acid percentage was identified in the six women with preeclampsia (p = 0.0233). Tumor necrosis factor-alpha levels were inversely proportional to the palmitic acid percentage (p = 0.0275) and positively associated with the percentages of stearic (18:0) (p = 0.0132) and oleic (p = 0.0290) acids. Conclusions: Amniotic fluid fatty acid composition differed among the ethnic groups and may influence inflammatory mediator production and susceptibility to preeclampsia.

Amniotic Fluid Interleukin-1 Beta and Interleukin-6, but not Interleukin-8 Correlate with Microbial Invasion of the Amniotic Cavity in Preterm Labor

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)