Studio dell'espressione del gene SREBP-1 e sue relazioni con la componente lipidica del latte ovino

Sterol Regulator Element Binding Proteins (SREBPs) are a family of transcription factors that plays a central role in lipids synthesis in mammary gland. The main aims of this research were: to develop a method for RNA extraction from milk somatic cells without damaging the mammary gland; to study SREBP-1 gene expression in the Sarda breed sheep in the first stage of lactation; and to correlate it to fatty acids in milk. In order to develop extraction method 4 milk samples were collected weekly from 15 sheep. The first 3 samples were analysed within 4 hours of collection, while the last one was divided into 2 aliquots of 150ml; one of this was analysed within 4 h and the other one at 24h. Twenty sheep have been used for the SREBP1 gene expression study with RTqPCR and from each ewe two milk samples at 40 and 70 days of lactation were collected. These samples were used for RNA extraction and for fatty acids quantification with gas chromatography method. The developed method has shown to be reliable and repeatable; 150ml of milk are enough to provide good amount and quality of RNA, suitable for study of gene expression. SREBP -1 gene expression showed a positive correlation with the fat yield (P<0,001) while no correlation with the range of fatty acid was found. The relationship between SREBP-1 gene and the amount of fat yield suggests the importance of this gene for lipids synthesis mechanism in mammary gland

Genotype of Melatonin Receptor MT1 (MTNR1A) and Puberty in Mediterranean Italian Buffalo

In adult buffaloes, polymorphism of the MT1 receptor gene has shown to influence the reproductive seasonality. The aim of study was to assess whether the polymorphism of the MTNR1A gene may influence puberty in Mediterranean Italian buffalo. The study was conducted using 50 prepubertal buffalo cows that at the age of 15 months were placed into the group where there was the male. Estrus detection was performed by observing estrous-behaviour and pregnancy checking by palpation per rectum and/or ultrasound between days 40 and 60 post-mating. Also of each animal dates of calving was recorded. From each buffalos a blood sample was collected and used for DNA extraction. PCR analysis was performed using 100-150 ng of DNA to amplify the second exon of the MTNRA1 gene. All PCR products were digested with 2U of enzyme HpaI to highlight the polymorphism at position 82 (characterized by a C to a T substitution) of the MTNR1A gene. Frequency of C and T alleles was respectively 0.42 and 0.58 in the analyzed population which resulted in Hardy Weinberg equilibrium. The genotypic frequency was 28% for genotype C/C, 38% for C/T and 34% for T/T. The registration of reproductive data showed that the first heat is around the age of 20 months and the first calving around 32 months. Our data show that the genotype of the MTNR1A does not influence the onset of reproductive activity in prepubertal buffalo cows

A δ∑ Dithering-Amplification-Based Identification Technique for Online SMPS

A novel nonparametric system identification (SI) algorithm is described, focusing on PID-based control loops for buck converters with effective series resistance (ESR) in the output filter. Dithering amplification effects on the control path are exploited during the steady-state converter operation. The noise injected is used to stimulate the loop reaction and to identify the output filter configuration. Oversampling-dithering features of third-order δ σ modulators are used to increase the DPWM resolution during the converter nominal operation and, moreover, as the core key to compute the SI algorithm. A modified structure of a noise shaper is used to handle the resolution of the SI algorithm over a range of the desired frequencies during the nonparametric identification. The SI algorithm comprises two steps: The first processing step extracts the resonant frequency, and the second extracts the ESR zero from the power spectrum density computation of the control feedback error. The SI method has been validated with different buck converter configurations, and has successfully been integrated and measured into a digitally controlled buck converters prototype for automotive safety application