Magnetic resonance study of a vanadium pentoxide gel

In this work we report results from continuous-wave (CW) and pulsed electron paramagnetic resonance (EPR) and proton nuclear magnetic resonance (NMR) studies of the vanadium pentoxide xerogel V2O5:nH(2)O (n approximate to 1.6). The low temperature CW-EPR spectrum shows hyperfine structure due to coupling of unpaired V4+ electron with the vanadium nucleus. The analysis of the spin Hamiltonian parameters suggests that the V4+ ions are located in tetragonally distorted octahedral sites. The transition temperature from the rigid-lattice low-temperature regime to the high temperature liquid-like regime was determined from the analysis of the temperature dependence of the hyperfine splitting and the V4+ motional correlation time. The Electron Spin Echo Envelope Modulation (ESEEM) data shows the signals resulting from the interaction of H-1 nuclei with V4+ ions. The modulation effect was observed only for field values in the center of the EPR absorption spectrum corresponding to the single crystals orientated perpendicular to the magnetic field direction. At least three protons are identified in the xerogel by our magnetic resonance experiments: (I) the OH groups in the equatorial plane, (ii) the bound water molecules in the axial V=O bond and (iii) the free mobile water molecules between the oxide layers. Proton NMR lineshapes and spin-lattice relaxation times were measured in the temperature range between 150 K and 323 K. Our analysis indicates that only a fraction of the xerogel protons contribute to the measured conductivity.

Molecular Basis of the Thermostability and Thermophilicity of Laminarinases: X-ray Structure of the Hyperthermostable Laminarinase from Rhodothermus marinus and Molecular Dynamics Simulations

Glycosyl hydrolases are enzymes capable of breaking the glycosidic linkage of polysaccharides and have considerable industrial and biotechnological applications. Driven by the later applications, it is frequently desirable that glycosyl hydrolases display stability and activity under extreme environment conditions, such as high temperatures and extreme pHs. Here, we present X-ray structure of the hyperthermophilic laminarinase from Rhodothermus marinus (RmLamR) determined at 1.95 angstrom resolution and molecular dynamics simulation studies aimed to comprehend the molecular basis, for the thermal stability of this class of enzymes. As most thermostable proteins, RmLamR contains a relatively large number of salt bridges, which are not randomly distributed on the structure. On the contrary, they form clusters interconnecting beta-sheets of the catalytic domain. Not all salt bridges, however, are beneficial for the protein thermostability: the existence of charge-charge interactions permeating the hydrophobic core of the enzymes actually contributes to destabilize the structure by facilitating water penetration into hydrophobic cavities, as can be seen in the case of mesophilic enzymes. Furthermore, we demonstrate that the mobility of the side-chains is perturbed differently in each class of enzymes. The side-chains of loop residues surrounding the catalytic cleft in the mesophilic laminarinase gain mobility and obstruct the active site at high temperature. By contrast, thermophilic laminarinases preserve their active site flexibility, and the active-site cleft remains accessible for recognition of polysaccharide substrates even at high temperatures. The present results provide structural insights into the role played by salt-bridges and active site flexibility on protein thermal stability and may be relevant for other classes of proteins, particularly glycosyl hydrolases.

Crystallization and Preliminary Crystallographic Analysis of Laminarinase from Rhodothermus marinus: A Case of Pseudomerohedral Twinning

Thermophilic endo-1,3(4)-beta-glucanase (laminarinase) from Rhodothermus marinus was crystallized by the hanging-drop vapor diffusion method. The needle-like crystals belong to space group P2(1) and contain two protein molecules in the asymmetric unit with a solvent content of 51.75%. Diffraction data were collected to a resolution of 1.95 angstrom and resulted in a dataset with an overall R-merge of 10.4% and a completeness of 97.8%. Analysis of the structure factors revealed pseudomerohedral twinning of the crystals with a twin fraction of approximately 42%.

Rankamaite from the Urubu pegmatite, Itinga, Minas Gerais, Brazil: Crystal chemistry and Rietveld refinement

A new occurrence of rankamaite is here described at the Urubu pegmatite, Itinga municipality, Minas Gerais, Brazil. The mineral forms cream-white botryoidal aggregates of acicular to fibrous crystals, intimately associated with simpsonite, thoreaulite, cassiterite, quartz, elbaite, albite, and muscovite. The average of six chemical analyses obtained by electron microprobe is (range in parentheses, wt%): Na(2)O 2.08 (1.95-2.13), K(2)O 2.61 (2.52-2.74), Al(2)O(3) 1.96 (1.89-2.00), Fe(2)O(3) 0.01 (0.00-0.03), TiO(2) 0.02 (0.00-0.06), Ta(2)O(5) 81.04 (79.12-85.18), Nb(2)O(5) 9.49 (8.58-9.86), total 97.21 (95.95-101.50). The chemical formula derived from this analysis is (Na(1.55)K(1.28))(Sigma 2.83)(Ta(8.45)Nb(1.64)Al(0.89)Fe(0.01)(3+)Ti(0.01))(Sigma 11.00)[O(25.02)(OH)(5.98)](Sigma 31.00). Rankamaite is an orthorhombic ""tungsten bronze"" (OTB), crystallizing in the space group Cmmm. Its unit-cell parameters refined from X-ray diffraction powder data are: a = 17.224(3), b = 17.687(3), c = 3.9361(7) angstrom, V = 1199.1(3) angstrom(3), Z = 2. Rietveld refinement of the powder data was undertaken using the structure of LaTa(5)O(14) as a starting model for the rankamaite structure. The structural formula obtained with the Rietveld analyses is: (Na(2.21)K(1.26))Sigma(3.37)(Ta(9.12)NB(1.30) Al(0.59))(Sigma 11.00)[O(26.29)(OH)(4.71)](Sigma 31.00). The tantalum atoms are coordinated by six and seven oxygen atoms in the form of distorted TaO(6) octahedra and TaO(2) pentagonal bipyramids, respectively. Every pentagonal bipyramid shares edges with four octahedra, thus forming Ta(5)O(14) units. The potassium atom is in an 11-fold coordination, whereas one sodium atom is in a 10-fold and the other is in a 12-fold coordination. Raman and infrared spectroscopy were used to investigate the room-temperature spectra of rankamaite.

Prevalence of hepatitis B and C serological markers among first-time blood donors in Brazil: A multi-center serosurvey

Little data are available on the seroprevalence of, and risk factors for hepatitis B and C viruses (HBV and HCV) infection in Latin American countries. A multi-center serosurvey was conducted among 3,598 first-time blood donors (65% men) from Sao Paulo, Salvador and Manaus in Brazil. The gender-specific seroprevalences of antibodies against hepatitis B core antigen (anti-HBc) and of the hepatitis B surface antigen (HBsAg) in anti-HBc-positive sera were measured, and risk factors analyzed by gender. The gender-specific seroprevalences of antibodies against HCV (anti-HCV) were measured, but risk factors for HCV were not determined. Anti-HBc and HBsAg seroprevalences were not significantly different in men [101/2,341 (4.31%) and 4/2,229 (0.18%), respectively] and women [65/1,237 (5.25%) and 8/ 1,169 (0.68%), respectively], whereas the seroprevalence of anti-HCV was higher in women (12/1,238 [0.97%] vs. 9/2,353 [0.38%]; odds ratio [OR] = 2.49; 95% confidence interval [Cl]: 1.0-6.0). No significant difference for HBV infection was found across the three study sites or by ethnic group. The seroprevalence of anti-HBc increased with age, but decreased with education level in both genders. Lifetime number of sexual partners was associated with anti-HBc prevalence among men (OR = 1.95; 95% Cl: 1.2-3.1), but not women. The seroprevalence of HBV and HCV was low among Brazilian blood donors, and exposure increased with age in both genders.

Preparation of supported Pt(0) nanoparticles as efficient recyclable catalysts for hydrogenation of alkenes and ketones

A magnetically recoverable Pt(0) catalyst was prepared by in situ H(2) reduction of Pt(2+) species bound to an amino modified silica-coated magnetic nanoparticles. Compared to ordinary silica (maximum uptake Pt 0.03 wt%), the amino-functionalized silica surfaces were loaded with 1.95 wt% of metal. The supported Pt(0) nanoparticles exhibit high catalytic activity in the hydrogenation of alkenes and ketones under solventless mild reaction conditions. Partially hydrogenated products could also be isolated. The magnetic property of the catalyst grants a fast and efficient product isolation compared to traditional methods used in heterogeneous systems that generally make use of time- and solvent-consuming procedures. (C) 2009 Elsevier B.V. All rights reserved.

Acupuncture for labour pain

Background: Acupuncture involves puncturing the skin with thin sterile needles at defined acupuncture points. Previous studies are inconclusive regarding the effect of acupuncture on labour pain, but some studies have found a reduction in the use of pharmacological pain relief when acupuncture is administered. The appropriate dose of acupuncture treatment required to elicit a potential effect on labour pain has not been fully explored. The dose is determined by many different factors, including the number of needles used and the intensity of the stimulation. In Sweden, manual stimulation of the needles is common practice when acupuncture is used for labour pain, but electrical stimulation of the needles, which gives a higher dose, could possibly be more effective. The overall aim of this thesis was to evaluate the effectiveness of acupuncture with manual stimulation (MA) of the needles as well as acupuncture with a combination of manual and electrical stimulation (EA) in reducing labour pain, compared with standard care without any form of acupuncture (SC). Methods: The study was designed as a three-armed randomised controlled trial in which 303 nulliparous women with normal pregnancies were randomised to MA, EA, or SC. The primary outcome was labour pain, assessed using the Visual Analogue Scale (VAS). Secondary outcomes were relaxation during labour, use of obstetric pain relief, and associations between maternal characteristics and labour pain and use of epidural analgesia respectively. Also, labour and infant outcomes, recollection of labour pain, and maternal experiences, such as birth experience and experience of the midwife, were investigated two months after the birth. The sample size calculation was based on the potential to discover a difference of 15 mm on the VAS. Data were collected during labour before the interventions, the day after birth, and two months later. Besides using the VAS, information was collected by means of study specific protocol, questionnaires and medical records. Results: The mean VAS scores were 66.4 in the MA group, 68.5 in the EA group, and 69.0 in the SC group (mean differences: MA vs. SC 2.6 95% CI -1.7 to 6.9, and EA vs. SC 0.6 95% CI -3.6 to 4.8). Other methods of pain relief were used less frequently in the EA group, including epidural analgesia, MA 61.4%, EA 46%, and SC 69.9%. (EA vs. SC OR 0.4 95% CI 0.2 to 0.7). No statistically significant differences were found in the recollection of labour pain between the three groups two months after birth (mean VAS score: MA 69.3, EA 68.7 and SC 70.1). A few maternal characteristics were associated with labour pain (age, dysmenorrhea, and cervix dilatation), but none of the investigated characteristics predicted the outcome of the acupuncture treatment in MA or EA. Women in the EA group experienced acupuncture as being effective for labour pain to a higher extent than women who received MA, MA 44.4%, EA 67.1% (EA vs. MA OR 2.4 95% CI 1.2 to 4.8). Women in the EA group also spent less time in labour (mean 500 min) than those who received MA (mean 619 min) and SC (mean 615 min) (EA vs. MA HR 1.4 95% CI 1.0 to1.9, EA vs. SC HR 1.4, 95% CI 1.1 to 2.0), and had less blood loss than women receiving SC, (EA vs. SC OR 0.1 95% CI 0.3 to 0.7). The women’s assessment of the midwife as being supportive during labour (MA 77.2%, EA 83.5%, SC 80%), overall satisfaction with midwife care (MA 100%, EA 97.5%, SC 98.7%), and having an overall positive childbirth experience (MA 64.6%, EA 61.0%, SC 54.3%) did not differ statistically. No serious side effects of the acupuncture treatment were reported. Conclusion: Acupuncture, regardless of type of stimulation, did not differ from standard care without acupuncture in terms of reducing women’s experience of pain during labour, or their memory of pain and childbirth overall two months after the birth. However, other forms of obstetric pain relief were less frequent in women receiving a combination of manual and electrical stimulation, suggesting that this method could facilitate coping with labour pain.

Estudos eletroquímicos de permeação de hidrogênio e determinação de concentrações críticas de hidrogênio em um aço de alta dureza

Estudou-se, através do método eletroquímico de permeação, a difusão de hidrogênio no ferro puro e no aço DIN 90MnV8. Observou-se nestes materiais, que o coeficiente aparente de difusão de hidrogênio diminui no decorrer dos transientes de permeação, tendo-se interpretado este comportamento como causado pela presença de armadilhas reversíveis. Deduziu-se, para transientes de permeação obtidos entre dois estados estacionários de difusão, que a variação da concentração de hidrogênio preso a armadilhas reversiveis é dada por: Delta Ca = Na. In [(1+alfa)1/2 dividido por (1+beta)1/2], alfa = K.Co/p beta=K.Cl/p sendo Na a densidade de armadilhas; k e p, os parâmetros de captura e de liberação de uma armadilha e Co e Cl, a concentrasão inicial e final de H. Mediu-se, no ferro recozido, um coeficiente médio de difusão de hidrogênio de 6,4.10-5 cm²/s. A deformação com 50% de trabalho a frio no ferro reduz este valor em aproximadamente uma ordem de grandeza. Verificou-se no aço DIN 90MnV8 que o coeficiente de difusão de hidrogênio aumenta com o aumento dn temperatura de revenimento após a têmpera, atingindo o valor máximo de 7,0.10-6 cm²/s no aço esferoidizado. A dependência térmica do coeficiente de difusão no aço DIN 90MnV8 esferoidizado pode ser expressa por: D = 1,95 (+0,49) exp (-30,43kJ/mol.R.T.) (cm²/s) e neste mesmo aço temperado e revenido com 55RC de dureza por : D=0,29 (+- 0,05 ) exp (-28,47kJ/mol.R.T.) ( cm²/s). Uma nova metodolagia fractomecânica foi introduzida, a qual permite a determinação da cnncentração crítica de hidrogênio necessária para provocar o avanço de uma trinca estacionária. Observou-se no aço DIN 9OMnV8, que a concentração crítica de hidrogênio diminui com o aumento da dureza do aço e é menor quando um valor maior de KI é aplicado. O modo de fratura apresentado Por este aço revelou ser independente da concentração de hidrogênio e do valor de KI, sendo função unicamente de sua dureza.

Oxidação e eficiência agronômica do enxofre elementar em solos do Brasil

O uso do enxofre (S) elementar como fertilizante, isoladamente ou associado a fórmulas NPK, pode reduzir os custos de adubação em solos deficientes de enxofre. Com o objetivo de avaliar a viabilidade de utilização do S elementar como fonte de nutriente para as plantas, foram realizados cinco estudos com 42 amostras de solos de vários estados do Brasil. A incubação das amostras dos solos com S elementar a 27o C demonstrou que estes solos têm capacidade de oxidar S elementar a S-sulfato, forma disponível à planta. As taxas de oxidação obtidas variaram entre 1,95 µg S0 cm-2 dia-1 e 65,70 µg S0 cm-2 dia-1 e apresentaram, entre os atributos dos solos estudados, correlação positiva com o teor de matéria orgânica e correlação negativa com o teor de alumínio e com o teor de enxofre. Porém, a interação entre os atributos dos solos foi o que melhor explicou a oxidação do S elementar. Métodos que determinam o teor de sulfato no solo, após seis dias de incubação com S elementar, foram inadequados para estimar a taxa de oxidação quando comparados aos métodos que utilizam, para esta estimativa, o S elementar remanescente no solo. Estudos em casa-de- vegetação com quatro cultivos consecutivos de milho para comparar a eficiência de fontes de S indicaram que fertilizantes granulados apenas com S elementar e com aditivos dispersantes apresentaram índice de eficiência agronômica menor do que 50%. Fontes em que o S elementar foi adicionado ao superfosfato triplo, tiveram sua eficiência aumentada com o decorrer dos cultivos, destacando-se o fertilizante em que o S elementar, na forma de pó, foi incorporado, antes da granulação, ao superfosfato, que atingiu um índice de eficiência agronômica acima de 160% no quarto cultivo.

Prevalência de sintomas do climatério em mulheres dos meios rural e urbano no Rio Grande do Norte, Brasil

OBJETIVO: avaliar a sintomatologia climatérica e fatores relacionados entre mulheres dos meios urbano e rural do Rio Grande do Norte. MÉTODOS: estudo transversal, descritivo, envolvendo casuística de 261 mulheres climatéricas residentes em Natal e Mossoró (grupo urbano; n=130) e Uruaçu, em São Gonçalo do Amarante (grupo rural; n=131). A sintomatologia climatérica foi avaliada pelo Índice Menopausal de Blatt-Kupperman (IMBK) e Escala Climatérica de Greene (ECG). A análise estatística constou de comparações das medianas dos escores entre os grupos e regressão logística. Defi niram-se como “muito sintomáticas” as pacientes com escores ≥20, para ambos instrumentos (variável dependente). As variáveis independentes foram: idade, procedência, alfabetização, obesidade e prática de atividade física. RESULTADOS: o grupo urbano apresentou escores signifi cativamente superiores ao grupo rural, tanto para o IMBK (medianas de 26,0 e 17,0, respectivamente; p<0,0001), quanto para a ECG (medianas de 27,0 e 16,0, respectivamente; p<0,0001). Na amostra total, evidenciou-se que 56,3% (n=147) das mulheres foram classifi cadas como “muito sintomáticas”. Na comparação intergrupos, essa prevalência foi signifi cativamente mais elevada nas mulheres urbanas em relação às rurais (79,2 e 33,6%, respectivamente; p<0,05). Pela análise de regressão logística, evidenciou-se que a chance de pertencer ao grupo defi nido como “muito sintomáticas” foi maior para mulheres do meio urbano [odds ratio ajustado (OR)=7,1; 95% intervalo de confi ança a 95% (IC95%)=3,69-13,66] e alfabetizadas (OR=2,19; IC95%=1,16-4,13). A idade superior a 60 anos associou-se com menor chance de ocorrência de sintomas signifi cativos (OR=0,38; IC95%=0,17-0,87). CONCLUSÕES: a prevalência de sintomas climatéricos signifi cativos é menor em mulheres do meio rural, demonstrando que fatores socioculturais e ambientais estão fortemente relacionados ao surgimento dos sintomas climatéricos em nossa população.___________________________________ABSTRACT PURPOSE: to evaluate climacteric symptoms and related factors in women living in rural and urban areas of Rio Grande do Norte, Brazil. METHODS: a cross-sectional study involving 261 women in the climacteric was performed. A total of 130 women from Natal and Mossoró (urban group) and 131 from Uruaçu, in São Gonçalo do Amarante (rural group), were studied. Climacteric symptoms were assessed by the Blatt-Kupperman Menopausal Index (BKMI) and Greene Climacteric Scale (GCE). Statistical analysis involved comparison of median between groups and logistic regression analysis. Patients were defi ned as “very symptomatic” when the climacteric score was ≥20 for both questionnaires (dependent variable). Independent variables were: age, living area, schooling, obesity and physical activity. RESULTS: the urban group had signifi cantly higher scores than those of the rural group, both for BKMI (median of 26.0 and 17.0, respectively; p<0.0001) and for GCE (median of 27.0 and 16.0, respectively; p<0.0001). For the entire sample, a total of 56.3% (n=147) of the women were classifi ed as “very symptomatic”. This prevalence was signifi cantly higher in urban than in rural women (79.2 and 33.6%, respectively; p<0.05). Logistic regression analysis showed that the likelihood of belonging to the group defi ned as “very symptomatic” was greater for urban women [adjusted odds ratio (OR)=7.1; confi dence interval at 95% (95%CI)=3.69-13.66] who were literate (OR=2.19; 95%CI=1.16- 4.13). Individuals over the age of 60 years had less chance of having signifi cant symptoms (OR=0.38; 95%CI=0.17-0.87). CONCLUSIONS: the prevalence of signifi cant climacteric symptoms is less in women from a rural environment, showing that sociocultural and environmental factors are strongly related to the appearance of climacteric symptoms in our population

Características físico-qímicas da carne de caprinos submetidos a diferentes níveis de substituição do leite por soro de queijo durante o aleitamento

Fifty six crossbred kids Parda Alpina x Gurgueia were separeted into four groups of 14 (seven male and seven female) and submited to four treatments with different levels of milk goat substitution by cheese serum. The treatments were : T1=milk goat (testify); T2=15% serum at 23 days and 33% at 55 days; T3=15% serum starting from 16 days, 33% on 23 days and 51% on 72 days of age; and T4=33% on 16 days and 69% of liquid diet in the final fase. At 92 days of age, all animals were slaughtered for carcass evaluation. Pallete were separeted from 20 male animals (five by treatment) and the physical and chemical analysis of the meat were realized using these materials. The studied characteristics were: total weight (TW), meat weight (MW), bone weigth (BW) of the pallete, and percentage of umidity (U), ashes (A), protein (P), fat (F) and pH of the pallete meat. There was significant effect of the treatment over F. Means of PW, A and BW were, respectively 491, 342 and 149.8 g. The meal represented 69,6% of total pallete weight. Means of U, A, P and F were 73, 1.0, 19 and 1.95%, respectively. The pH was 6.7. Results allow to conclude that only the fat percentage of the meat was modified, due to the administration of serun milk on the liquid diet of the kids, during the milking fase.

Results of 23 years of selection for post-weaning weight in a Caracu beef herd

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influência de lâminas de água e adubação mineral na nutrição e produtividade de arroz de terras altas

Para recomendações de adubação mais racionais, é fundamental o conhecimento das exigências nutricionais da cultura do arroz, nos diversos sistemas de cultivo. Objetivando estudar a influência de lâminas de água na nutrição e exportação de nutrientes pelo arroz de terras altas, cultivar IAC 201, sob dois níveis de adubação, foram instalados experimentos em um Latossolo Vermelho distrófico, em Selvíria (MS), nos anos agrícolas de 1994/95 e 1995/96. O delineamento foi de blocos casualizados, com quatro repetições. Os tratamentos constituíram-se da precipitação natural e de quatro lâminas de água fornecidas por aspersão. A lâmina L2 foi baseada no coeficiente de cultura (Kc) do arroz de terras altas. As lâminas L1 e L3 foram definidas como 0,5 e 1,5 vez os Kcs utilizados em L2, respectivamente, e na lâmina L4 foi adotado Kc = 1,95 durante todo o ciclo da cultura. em 1995/96, foram utilizados os mesmos tratamentos em parcelas subdivididas, sendo as subparcelas constituídas por duas doses de adubação (AD1 - 12 kg ha-1 de N, 90 de P2O5 e 30 de K2O, e AD2 - 24 kg ha-1 de N, 180 de P2O5 e 60 de K2O). A menor disponibilidade de água durante a fase vegetativa e reprodutiva proporcionou redução na produção de matéria seca, nos teores e quantidades de nutrientes acumuladas na parte aérea. O sistema irrigado por aspersão, independentemente da lâmina utilizada, proporcionou maior produtividade de grãos e exportação de nutrientes. em solos com teores adequados de nutrientes para o sistema de sequeiro, não há resposta ao aumento da adubação mineral pelo arroz no sistema irrigado por aspersão, apesar da maior extração de nutrientes.

Desenvolvimento de protótipo de coletor automático destinado à coleta de amostras de água em corpos aquáticos para análise em laboratório

The aim of this approach is to describe the design and construction of a low-cost automated water sampler prototype. In recent years, there is an increasing need on the use of automated equipments for hydro climatic variables to be use in urban and rural environments. Such devices are always used to provide measured information which is of crucial importance on the development of water resources strategies at watershed scale. Actually, many research and water public institutions have been using these kinds of equipments. In most of the cases, automated equipments are expensive and need to be imported, generating a situation of technologic dependency. The prototype is based on an electronic system which controls a peristaltic pump functioning, five solenoid valves and an ultrasonic sensor connected to a datalloger. An interface with the user allows communication with a PC, when the equipment functioning parameters can be provided. The equipment has a hydraulic module composed by a 12V peristaltic pump connected to a distribution circuit composed by five solenoid valves, one of them being used to clean the circuit before each sampling procedure. Samples are collected by four 1.95 polyethylene bottles. The sampler body was made of acrylic material, with a cylindrical shape, and dimensions 0.72 m and 0.38 m height and diameter, respectively. The weight of the equipment without samples is approximately 15 kg, which infers to its portability. The prototype development total cost budget was approximately US$ 1,560.00. Laboratory tests aimed to evaluate the equipment performance and functioning demonstrated satisfactory results

Effects of different disinfection treatments on the natural microbiota of lettuce

In this study, water and eight sanitizing solutions (vinegar at 6, 25, and 50%; acetic acid at 2 and 4%; peracetic acid at 80 ppm, sodium hypochlorite at 200 ppm, and sodium dichloroisocyanurate at 200 ppm) were compared in terms of their effectiveness against the natural microbiota of lettuce. All of the samples were kept in contact with the sanitizing solutions for 15 min, and the effectiveness of a sanitizing agent was evaluated on the basis of the number of decimal reductions of the total aerobic mesophilic count, the mold and yeast count, the total coliform count, and the Escherichia coli count. The average initial levels of these organisms in the samples were 6.94 log(10) CFU/g for aerobic mesophilic microorganisms, 5.62 log(10) CFU/g for molds and yeasts, and 3.25 log(10) CFU/g for total coliforms. of 10 samples analyzed, only 4 contained E. coli, and the average initial level of this microorganism in these 4 samples was 1.64 log(10) CFU/g. Salmonella was not detected in any of the samples tested. The decimal reductions of the populations of aerobic mesophilic microorganisms, molds and yeasts, total coliforms, and E. coli were 0.78, 0.87, 0.82, and >0.14 log(10) CFU/g, respectively, in water; 2.89, >3.41, >2.21, and >0.26 log(10) CFU/g, respectively, in 50% vinegar; 2.42, >3.20, >1.99, and >0.26 log(10) CFU/g, respectively, in 25% vinegar; 1.83, 2.57, 1.58, and >0.26 log(10) CFU/g, respectively, in 6% vinegar; 3.91, >3.58, >2.25, and >0.26 log(10) CFU/g, respectively, in 4% acetic acid; 3.37, >3.53, >2.25, and >0.26 log(10) CFU/g, respectively, in 2% acetic acid; 1.85, 2,32, 1.44, and >0.20 log(10) CFU/g, respectively, in 80 ppm of peracetic acid; 2.63, 2.75, 1.91, and >0.26 log(10) CFU/g, respectively, in 200 ppm of sodium hypochlorite; and 3.23, >3.08, >1.95, and >0.26 log(10) CFU/g, respectively, in 200 ppm of sodium dichloroisocyanurate. Statistical analysis of the results showed that the effectiveness levels for all of the sanitizing agents tested were equivalent to or higher than that for sodium hypochlorite at 200 ppm.