Synthesis of fragments of Salmonella Typhi capsular polysaccharide and their zwitterionic analogues

We will report on the synthesis of oligomers of Salmonella enterica serovar Typhi (often called S. Typhi) CPS, and their zwitterionic analogues. S. Typhi is a motile Gram-negative bacterium, whose CPS (often referred to as Vi antigen) is an anionic polymer composed by \u3b1-(1-4)-linked N-acetyl galactosaminuronic acid repeating units predominantly O-acetylated at position 3. We developed a strategy based on versatile intermediates enabling chain elongation either by iterative single monomer attachment or by faster and more flexible approaches using disaccharide donors. All these intermediates were obtained from commercially available D-galactosamine hydrochloride. The non participating azide group was used to mask C-2 amino functionality, which can be converted into the animo group (ZPS) or into the acetamido function (natural Vi) and allows the formation of 1,2-cis glycosidic linkages. Glycosylation reactions were carried out using N-phenyltrifluoroacetimidates as glycosyl donors, yielding stereoselectively the desired \u3b1 product. C-6 oxidation was done with TEMPO/NaClO2. By orthogonally protecting position 3 we were able to obtain both fully 3-O-acetylated and fully 3-O-deactetylated oligomers. Finally, a suitable l inker was installed at C-1 of the reducing end in order to facilitate a subsequent conjugation to protein carrier and/or multivalents caffolds. The immunological properties of the synthetic oligomers will be also investigated in order to correlate the structural features (in particular 3-O-acetylation) with their biological behaviour

Annual Variation Of Sex Ratio In Twin Births And In Singletons In Brazil

The annual variation of the sex ratio (SR) of 1385 twin births was analyzed and compared to that of 85909 singletons. These births referred not only to live births but also to stillbirths in two southeastern Brazilian maternity hospitals from 1984 to 1993. While the annual variation of the SR of singletons was very small, that of twin births was extremely high, due to the significant heterogeneity of the annual data. It is suggested that the large SR annual variation of the twin birth might be a consequence of the variation of male or female monozygotic twins. The hypothesis that twin births show a lower sex ratio than singletons could not be supported by the present data.This article presents the findings of a study of the annual variation of the sex ratio among twin births compared to singleton births among a maternity population in two urban hospitals in Brazil. Data are obtained from hospital records from a maternity hospital in Campinas and Sao Paulo, Brazil, during 1984-93. There were 1385 twin births and 85,909 singleton births delivered during 1984-93 in these maternity hospitals in Sao Paulo state. Deliveries included stillbirths weighing 500 g or more. Findings indicate that the sex ratio of singletons was 104.6 males per 100 females. The sex ratio of the 763 twins born in Campinas and the 622 twins born in Sao Paulo showed considerable variation from the mean sex ratio of singleton births. The mean sex ratio among twins in Campinas was 107.1 males per 100 females, with a standard deviation of 20.4 in Campinas and 29.7 in Sao Paulo. There were significant differences from the mean sex ratio among twin births in Campinas in 1984 and 1989 and in Sao Paulo in 1984, 1985, 1988, and 1989. There was significant heterogeneity of sex ratios among twin births even with pooled data. The mean of pooled data on twin births was 102.9 males per 100 females, with significant differences from the mean in 1984, 1985, and 1987. The application of Woolf's test indicated heterogeneity in the data and no effect on the sex ratio from twin births. Maternal age was negatively correlated with the sex ratio of twin births. It is argued that monozygotic twins were not primarily females and that twin births did not have a lower sex ratio than singleton births.443-416316

Synthesis of fragments of Salmonella Typhi capsular polysaccharide and their zwitterionic analogues

We will report on the synthesis of oligomers of Salmonella enterica serovar Typhi (often called S. Typhi) CPS, and their zwitterionic analogues. S. Typhi is a motile Gram-negative bacterium, whose CPS (often referred to as Vi antigen) is an anionic polymer composed by \u3b1-(1-4)-linked N-acetyl galactosaminuronic acid repeating units predominantly O-acetylated at position 3. We developed a strategy based on versatile intermediates enabling chain elongation either by iterative single monomer attachment or by faster and more flexible approaches using disaccharide donors. All these intermediates were obtained from commercially available D-galactosamine hydrochloride. The non participating azide group was used to mask C-2 amino functionality, which can be converted into the animo group (ZPS) or into the acetamido function (natural Vi) and allows the formation of 1,2-cis glycosidic linkages. Glycosylation reactions were carried out using N-phenyltrifluoroacetimidates as glycosyl donors, yielding stereoselectively the desired \u3b1 product. C-6 oxidation was done with TEMPO/NaClO2. By orthogonally protecting position 3 we were able to obtain both fully 3-O-acetylated and fully 3-O-deactetylated oligomers. Finally, a suitable l inker was installed at C-1 of the reducing end in order to facilitate a subsequent conjugation to protein carrier and/or multivalents caffolds. The immunological properties of the synthetic oligomers will be also investigated in order to correlate the structural features (in particular 3-O-acetylation) with their biological behaviour

Investigation On Seasonality Of Twin Births In Brazil

The hypothesis of seasonality of twin births was investigated in two important maternity hospitals in the State of Sao Paulo, Brazil. The study included 1386 twin births that occurred among 154,699 deliveries from 1984 to 1993. No evidence of seasonality has been detected either for the twin birth rate considered as a whole or for dizygotic twinning rate. The distributions of these rates fitted well sinusoidal regression curves but the cyclic trend did not correspond to any specific season.45439740

Annual Variation Of Sex Ratio In Twin Births And In Singletons In Brazil.

The annual variation of the sex ratio (SR) of 1385 twin births was analyzed and compared to that of 85909 singletons. These births referred not only to live births but also to stillbirths in two southeastern Brazilian maternity hospitals from 1984 to 1993. While the annual variation of the SR of singletons was very small, that of twin births was extremely high, due to the significant heterogeneity of the annual data. It is suggested that the large SR annual variation of the twin birth might be a consequence of the variation of male or female monozygotic twins. The hypothesis that twin births show a lower sex ratio than singletons could be supported by the present data.44163-

Estimativa do NDVI utilizando imagens do Sentinel-2 e do SIG SNAP para avaliação de estádios de degradação de pastagens em Alcinópolis-MS.

A pecuária bovina é uma atividade de extrema importância econômica para o Brasil, o que gera preocupação com a qualidade das pastagens disponíveis no nosso país e a sua produtividade. Assim, o objetivo deste estudo foi avaliar, no âmbito do projeto ?Mapeamento de níveis de degradação de pastagens no bioma Cerrado por meio de geotecnologias ? GeoPasto Cerrado?, a utilização do NDVI, obtido a partir de imagens Sentinel-2 e SIG SNAP, na diferenciação de níveis de degradação de pastagens cultivadas no município de Alcinópolis, MS. Foram utilizadas imagens Sentinel-2 de março/abril e agosto de 2019, correspondentes, respectivamente, aos períodos de fim das chuvas/início da seca e de plena seca. Foram adaptados os estádios de degradação das pastagens com intervalos de NDVI. Valores de NDVI apresentaram diferenças substanciais entre os períodos de março/abril e agosto. O NDVI obtido em março/abril possibilitou melhor distinção dos diferentes estádios de degradação das pastagens. A maioria das áreas de pastagens no município de Alcinópolis em 2019 era cultivada nas classes de solo Argissolo Vermelho distrófico e Neossolo Quartzarênico. As pastagens não degradadas eram cultivadas principalmente em Argissolo Vermelho distrófico, enquanto as pastagens no estádio de degradação muito forte estavam predominantemente em Neossolo Quartzarênico. Grande parte das pastagens cultivadas em março/abril não estava degradada, o equivalente a 65,4% das áreas de pastagens em Alcinópolis. Os resultados obtidos deverão ser validados a partir de levantamento em campo, a ser realizado pelo projeto GeoPasto Cerrado

Immediate Effects of Kinesiotaping on Quadriceps Muscle Strength: A Single-Blind, Placebo-Controlled Crossover Trial

OBJECTIVE: To investigate the immediate effects on maximal muscle strength of kinesiotaping (KT) applied to the dominant quadriceps of healthy subjects. DESIGN: Single-blind, placebo-controlled crossover trial. SETTING: "Salvatore Maugeri" Foundation. PARTICIPANTS: With ethical approval and informed consent, a convenience sample of 36 healthy volunteers were recruited. Two subjects did not complete the sessions and were excluded from the analysis. INTERVENTIONS: Subjects were tested across 3 different sessions, randomly receiving 2 experimental KT conditions applied with the aim of enhancing and inhibiting muscle strength and a sham KT application. MAIN OUTCOME MEASURES: Quadriceps muscle strength was measured by means of an isokinetic maximal test performed at 60 and 180 degrees per second. Two secondary outcome measures were performed: the single-leg triple hop for distance to measure limb performance and the Global Rating of Change Scale (GRCS) to calculate agreement between KT application and subjective perception of strength. RESULTS: Compared with baseline, none of the 3 taping conditions showed a significant change in muscle strength and performance (all P > 0.05). Effect size was very low under all conditions (≤0.08). Very few subjects showed an individual change greater than the minimal detectable change. Global Rating of Change Scale scores demonstrated low to moderate agreement with the type of KT applied, but some placebo effects were reported independently of condition. CONCLUSIONS: Our findings indicated no significant effect in the maximal quadriceps strength immediately after the application of inhibition, facilitation, or sham KT. These results do not support the use of KT applied in this way to change maximal muscle strength in healthy peoples