3,516 research outputs found

    Challenges in biotechnology of reproduction in dairy cattle: the antral follicle counting as a fertility parameter

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    Dairy farming plays an important role in the socioeconomic scenario, and several characteristics point to an enormous potential for growth in the productivity of the herd. This is a complex activity that needs to be carried out efficiently in all the links that integrate it. Moreover, due to the physiological and metabolic aspects of the animals with the aptitude for the milk production, several challenges arise, especially in the reproductive scope. In this context, breeding biotechniques appear as a good alternative to the increase in reproductive rates and genetic improvement of dairy cattle. In addition, ovarian antral follicle counts (AFC) have been studied as a way to improve the selection of females to compose reproductive programs, because it has been shown to be a factor of high repeatability over the reproductive life in the same animal. Although studies have shown controversial results regarding the relationship between AFC and fertility, it is still necessary to investigate the possible variables that may interfere with the performance of donors in each biotechnology used. Thus, this review intends to gather and discuss the relationship of AFC with physiological aspects of dairy cows, its application as a parameter of selection of animals with good fertility and, the challenges for the application of reproductive biotechniques in dairy cattle

    Unraveling the structure of sugarcane bagasse after soaking in concentrated aqueous ammonia (SCAA) and ethanol production by Scheffersomyces (Pichia) stipitis

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    Abstract\ud \ud \ud \ud Background\ud Fuel ethanol production from sustainable and largely abundant agro-residues such as sugarcane bagasse (SB) provides long term, geopolitical and strategic benefits. Pretreatment of SB is an inevitable process for improved saccharification of cell wall carbohydrates. Recently, ammonium hydroxide-based pretreatment technologies have gained significance as an effective and economical pretreatment strategy. We hypothesized that soaking in concentrated aqueous ammonia-mediated thermochemical pretreatment (SCAA) would overcome the native recalcitrance of SB by enhancing cellulase accessibility of the embedded holocellulosic microfibrils.\ud \ud \ud \ud Results\ud In this study, we designed an experiment considering response surface methodology (Taguchi method, L8 orthogonal array) to optimize sugar recovery from ammonia pretreated sugarcane bagasse (SB) by using the method of soaking in concentrated aqueous ammonia (SCAA-SB). Three independent variables: ammonia concentration, temperature and time, were selected at two levels with center point. The ammonia pretreated bagasse (SCAA-SB) was enzymatically hydrolysed by commercial enzymes (Celluclast 1.5 L and Novozym 188) using 15 FPU/g dry biomass and 17.5 Units of β-glucosidase/g dry biomass at 50°C, 150 rpm for 96 h. A maximum of 28.43 g/l reducing sugars corresponding to 0.57 g sugars/g pretreated bagasse was obtained from the SCAA-SB derived using a 20% v/v ammonia solution, at 70°C for 24 h after enzymatic hydrolysis. Among the tested parameters, pretreatment time showed the maximum influence (p value, 0.053282) while ammonia concentration showed the least influence (p value, 0.612552) on sugar recovery. The changes in the ultra-structure and crystallinity of native SCAA-SB and enzymatically hydrolysed SB were observed by scanning electron microscopy (SEM), x-ray diffraction (XRD) and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. The enzymatic hydrolysates and solid SCAA-SB were subjected to ethanol fermentation under separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) by Scheffersomyces (Pichia) stipitis NRRL Y-7124 respectively. Higher ethanol production (10.31 g/l and yield, 0.387 g/g) was obtained through SSF than SHF (3.83 g/l and yield, 0.289 g/g).\ud \ud \ud \ud Conclusions\ud SCAA treatment showed marked lignin removal from SB thus improving the accessibility of cellulases towards holocellulose substrate as evidenced by efficient sugar release. The ultrastructure of SB after SCAA and enzymatic hydrolysis of holocellulose provided insights of the degradation process at the molecular level.Financial support provided by Bioenergy-Fundação de Amparo a Pesquisa do Estado de São Paulo (BIOEN/FAPESP-Project Numbers: 2008/57926-4, 2010/11258-0) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) is gratefully acknowledged. We thank Dr. Durval Rodrigues Jr. from Engineering School of Lorena, University of São Paulo, Dr. Igor Polikarpov from University of São Paulo -São Carlos for SEM and XRD analysis respectively. Authors also thank Dr. Eduardo R. de Azevedo and Mr. Oigres D. Bernardinelli from University of São Paulo -São Carlos for NMR analysis.Financial support provided by BioenergyFundação de Amparo a Pesquisa do Estado de São Paulo (BIOEN/FAPESPProject Numbers: 2008/579264, 2010/112580) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) is gratefully acknowledged. We thank Dr. Durval Rodrigues Jr. from Engineering School of Lorena, University of São Paulo, Dr. Igor Polikarpov from University of São Paulo São Carlos for SEM and XRD analysis respectively. Authors also thank Dr. Eduardo R. de Azevedo and Mr. Oigres D. Bernardinelli from University of São Paulo São Carlos for NMR analysis

    SEASONAL VARIATIONS, METAL DISTRIBUTION AND WATER QUALITY IN THE TODOS OS SANTOS RIVER, SOUTHEASTERN BRAZIL: A MULTIVARIATE ANALYSIS

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    In aquatic habitats, metal contamination from natural and anthropogenic sources continues to pose a concern for human and environmental health. Thus, it is important to complete monitoring studies to assess patterns and the extent of metal contamination in these ecosystems. The objective of this study was to determine the concentrations of 31 chemical elements and water quality parameters of the Todos os Santos River located in the Mucuri Valley, Minas Gerais, Brazil and use multivariate statistical analyses to determine any seasonal and spatial patterns in the data. Results demonstrated that metals including Al, Fe, and Ni exceeded Brazilian and international guidelines for these elements with nutrients such as P also exceeding water quality standards. Principal components analysis indicated distinct geographical and seasonal patterns for multiple elements with hierarchical cluster analysis confirming the observed spatial patterns of contamination in the Todos os Santos River

    Dynapenia, abdominal obesity or both: which accelerates the gait speed decline most?

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    OBJECTIVE: to investigate whether the combination of dynapenia and abdominal obesity is worse than these two conditions separately regarding gait speed decline over time. METHODS: a longitudinal study was conducted involving 2,294 individuals aged 60 years or older free of mobility limitation at baseline (gait speed >0.8 m/s) who participated in the English Longitudinal Study of Ageing. Dynapenia was determined as a grip strength 102 cm for men and >88 cm for women. The participants were divided into four groups: non-dynapenic/non-abdominal obese (ND/NAO); only abdominal obese (AO); only dynapenic (D) and dynapenic/abdominal obese (D/AO). Generalised linear mixed models were used to analyse gait speed decline (m/s) as a function of dynapenia and abdominal obesity status over an 8-year follow-up period. RESULTS: over time, only the D/AO individuals had a greater gait speed decline (-0.013 m/s per year, 95% CI: -0.024 to -0.002; P < 0.05) compared to ND/NAO individuals. Neither dynapenia nor abdominal obesity only was associated with gait speed decline. CONCLUSION: dynapenic abdominal obesity is associated with accelerated gait speed decline and is, therefore, an important modifiable condition that should be addressed in clinical practice through aerobic and strength training for the prevention of physical disability in older adults

    Usefulness of Tissue Doppler Imaging to Predict Arrhythmic Events in Adults with Repaired Tetralogy of Fallot

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    INTRODUCTION: Adults with repaired tetralogy of Fallot (TOF) may be at risk for progressive right ventricular (RV) dilatation and dysfunction, which is commonly associated with arrhythmic events. In frequently volume-overloaded patients with congenital heart disease, tissue Doppler imaging (TDI) is particularly useful for assessing RV function. However, it is not known whether RV TDI can predict outcome in this population. OBJECTIVE: To evaluate whether RV TDI parameters are associated with supraventricular arrhythmic events in adults with repaired TOF. METHODS: We studied 40 consecutive patients with repaired TOF (mean age 35 +/- 11 years, 62% male) referred for routine echocardiographic exam between 2007 and 2008. The following echocardiographic measurements were obtained: left ventricular (LV) ejection fraction, LV end-systolic volume, LV end-diastolic volume, RV fractional area change, RV end-systolic area, RV end-diastolic area, left and right atrial volumes, mitral E and A velocities, RV myocardial performance index (Tei index), tricuspid annular plane systolic excursion (TAPSE), myocardial isovolumic acceleration (IVA), pulmonary regurgitation color flow area, TDI basal lateral, septal and RV lateral peak diastolic and systolic annular velocities (E' 1, A' 1, S' 1, E' s, A' s, S' s, E' rv, A' rv, S' rv), strain, strain rate and tissue tracking of the same segments. QRS duration on resting ECG, total duration of Bruce treadmill exercise stress test and presence of exercise-induced arrhythmias were also analyzed. The patients were subsequently divided into two groups: Group 1--12 patients with previous documented supraventricular arrhythmias (atrial tachycardia, fibrillation or flutter) and Group 2 (control group)--28 patients with no previous arrhythmic events. Univariate and multivariate analysis was used to assess the statistical association between the studied parameters and arrhythmic events. RESULTS: Patients with previous events were older (41 +/- 14 vs. 31 +/- 6 years, p = 0.005), had wider QRS (173 +/- 20 vs. 140 +/- 32 ms, p = 0.01) and lower maximum heart rate on treadmill stress testing (69 +/- 35 vs. 92 +/- 9%, p = 0.03). All patients were in NYHA class I or II. Clinical characteristics including age at corrective surgery, previous palliative surgery and residual defects did not differ significantly between the two groups. Left and right cardiac chamber dimensions and ventricular and valvular function as evaluated by conventional Doppler parameters were also not significantly different. Right ventricular strain and strain rate were similar between the groups. However, right ventricular myocardial TDI systolic (Sa: 5.4+2 vs. 8.5 +/- 3, p = 0.004) and diastolic indices and velocities (Ea, Aa, septal E/Ea, and RV free wall tissue tracking) were significantly reduced in patients with arrhythmias compared to the control group. Multivariate linear regression analysis identified RV early diastolic velocity as the sole variable independently associated with arrhythmic history (RV Ea: 4.5 +/- 1 vs. 6.7 +/- 2 cm/s, p = 0.01). A cut-off for RV Ea of < 6.1 cm/s identified patients in the arrhythmic group with 86% sensitivity and 59% specificity (AUC = 0.8). CONCLUSIONS: Our results suggest that TDI may detect RV dysfunction in patients with apparently normal function as assessed by conventional echocardiographic parameters. Reduction in RV early diastolic velocity appears to be an early abnormality and is associated with occurrence of arrhythmic events. TDI may be useful in risk stratification of patients with repaired tetralogy of Fallot
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