3,433 research outputs found
Variation of Milk Yield and Milk Composition of Pivska Pramenka Sheep Breed Through Lactation
The aim of this paper is to present the research results on the milk traits and variation of milk composition during lactation of Pivska pramenka breed, as one of the most important autochthonous sheep breeds in Montenegro. Investigation was conducted on the family sheep farm located in the municipality of Žabljak, a typical rearing area of Pivska pramenka breed.
The following milk traits were studied: length of lactation, milk yield (daily milk yield – DMY and total milk yield - TMY) and milk composition (Fat, Protein, Lactose, Solid non-fat - SNF and Somatic cells count - SCC).
Based on the data of 68 completed lactations, average length of lactation was 178.5 days and average milk yield 94.1 kg. On the basis of 289 milk samples analysed in 5 consecutive milk recordings, average daily milk yield was 0.549 litres, with 5.71% of fat, 5.75% of protein, 4.47% of lactose, 11.04 % of solid non-fat and 600x103 SCC on average.
Differences in averages for milk composition among test days (days of milk recording) during lactation were significant (P0.01). The largest variation was for milk fat, from 2.95% in the first control to 9.42% in the fifth control, while variation of protein was between 4.5% in the first and 7.4 in the fifth control. The content of lactose exposed decreasing trend during lactation (from 4.7% in first to 3.1% in fifth control)
The time and frequency comparisons via Loran-C and National TV Network in Yugoslavia
Time comparisons were made between cesium clocks in Yugoslavia and other cesium clocks in the country by the Laboratory of Federal Bureau of Measures and Precious Metals. Regional standard frequency and time signals dissemination is over National TV network by so called active TV system. International comparisons are performed via Loran-C system and by clock transportation. The method of calculation and approximation of the time signal propagation delays is given. Settled comparison results of the cesium clocks via TV network, Loran-C, and by clock transportation are also discussed in this paper
Regulation of Suppressors of Cytokine Signaling as a Therapeutic Approach in Autoimmune Diseases, with an Emphasis on Multiple Sclerosis
Multiple sclerosis (MS) is an inflammatory demyelinating, presumably autoimmune disease of the central nervous system (CNS). Among the available MS therapies, interferon (IFN)β and the recently introduced statins have been reported to exert their immunomodulatory effects through the induction of SOCS1 and SOCS3 in various inflammatory cell subsets. The SOCS proteins negatively regulate cytokine and Toll-like receptors- (TLR-) induced signaling in the inflammatory cells. SOCS1 and SOCS3 have been reported to play an important role in the regulation of Th17-cell differentiation through their effects on the cells of the innate and adaptive immune systems. IFNβ and statins inhibit Th17-cell differentiation directly and indirectly via induction of SOCS1 and SOCS3 expression in monocytes, dendritic cells (DCs), and B-cells. Due to their rapid induction and degradation, and SOCS-mediated regulation of multiple cytokine-signaling pathways, they represent an attractive therapeutic target in the autoimmune diseases, and particularly relapsing remitting (RR) MS
Vortices and the mixed state of ultrathin Bi films
Current-voltage (I-V) characteristics of quench condensed, superconducting,
ultrathin Bi films in a magnetic field are reported. These show hysteresis for
all films, grown both with and without thin Ge underlayers. Films on Ge
underlayers, close to superconductor-insulator transition, show a peak in the
critical current, indicating a structural transformation of the vortex solid.
These underlayers, used to make the films more homogeneous, are found to be
more effective in pinning the vortices. The upper critical fields () of
these films are determined from the resistive transitions in perpendicular
magnetic field. The temperature dependence of the upper critical field is found
to differ significantly from Ginzburg-Landau theory, after modifications for
disorder.Comment: Submitted to LT23 Proceeding
Transient down-regulation of beta1 integrin subtypes on kidney carcinoma cells is induced by mechanical contact with endothelial cell membranes
Adhesion molecules of the integrin beta1 family are thought to be involved in the malignant progression renal cell carcinoma (RCC). Still, it is not clear how they contribute to this process. Since the hematogenous phase of tumour dissemination is the rate-limiting step in the metastatic process, we explored beta1 integrin alterations on several RCC cell lines (A498, Caki1, KTC26) before and after contacting vascular endothelium in a tumour-endothelium (HUVEC) co-culture assay. Notably, alpha2, alpha3 and alpha5 integrins became down-regulated immediately after the tumour cells attached to HUVEC, followed by re-expression shortly thereafter. Integrin down-regulation on RCC cells was caused by direct contact with endothelial cells, since the isolated endothelial membrane fragments but not the cell culture supernatant contributed to the observed effects. Integrin loss was accompanied by a reduced focal adhesion kinase (FAK) expression, FAK activity and diminished binding of tumour cells to matrix proteins. Furthermore, intracellular signalling proteins RCC cells were altered in the presence of HUVEC membrane fragments, in particular 14-3-3 epsilon, ERK2, PKCdelta, PKCepsilon and RACK1, which are involved in regulating tumour cell motility. We, therefore, speculate that contact of RCC cells with the vascular endothelium converts integrin-dependent adhesion to integrin-independent cell movement. The process of dynamic integrin regulation may be an important part in tumour cell migration strategy, switching the cells from being adhesive to becoming motile and invasive
Vertex routing models
A class of models describing the flow of information within networks via
routing processes is proposed and investigated, concentrating on the effects of
memory traces on the global properties. The long-term flow of information is
governed by cyclic attractors, allowing to define a measure for the information
centrality of a vertex given by the number of attractors passing through this
vertex. We find the number of vertices having a non-zero information centrality
to be extensive/sub-extensive for models with/without a memory trace in the
thermodynamic limit. We evaluate the distribution of the number of cycles, of
the cycle length and of the maximal basins of attraction, finding a complete
scaling collapse in the thermodynamic limit for the latter. Possible
implications of our results on the information flow in social networks are
discussed.Comment: 12 pages, 6 figure
Gravitational Collapse with a Cosmological Constant
We consider the effect of a positive cosmological constant on spherical
gravitational collapse to a black hole for a few simple, analytic cases. We
construct the complete Oppenheimer-Snyder-deSitter (OSdS) spacetime, the
generalization of the Oppenheimer-Snyder solution for collapse from rest of a
homogeneous dust ball in an exterior vacuum. In OSdS collapse, the cosmological
constant may affect the onset of collapse and decelerate the implosion
initially, but it plays a diminishing role as the collapse proceeds. We also
construct spacetimes in which a collapsing dust ball can bounce, or hover in
unstable equilibrium, due to the repulsive force of the cosmological constant.
We explore the causal structure of the different spacetimes and identify any
cosmological and black hole event horizons which may be present.Comment: 7 pages, 10 figures; To appear in Phys. Rev.
The corticotrophin-releasing factor/urocortin system regulates white fat browning in mice through paracrine mechanisms
Objectives:
The corticotrophin-releasing factor (CRF)/urocortin system is expressed in the adipose tissue of mammals, but its functional role in this tissue remains unknown.
Methods:
Pharmacological manipulation of the activity of CRF receptors, CRF1 and CRF2, was performed in 3T3L1 white pre-adipocytes and T37i brown pre-adipocytes during in vitro differentiation. The expression of genes of the CRF/urocortin system and of markers of white and brown adipocytes was evaluated along with mitochondrial biogenesis and cellular oxygen consumption. Metabolic evaluation of corticosterone-deficient or supplemented Crhr1-null (Crhr1−/−) mice and their wild-type controls was performed along with gene expression analysis carried out in white (WAT) and brown (BAT) adipose tissues.
Results:
Peptides of the CRF/urocortin system and their cognate receptors were expressed in both pre-adipocyte cell lines. In vitro pharmacological studies showed an inhibition of the expression of the CRF2 pathway by the constitutive activity of the CRF1 pathway. Pharmacological activation of CRF2 and, to a lesser extent, inhibition of CRF1 signaling induced molecular and functional changes indicating transdifferentiation of white pre-adipocytes and differentiation of brown pre-adipocytes. Crhr1−/− mice showed increased expression of CRF2 and its agonist Urocortin 2 in adipocytes that was associated to brown conversion of WAT and activation of BAT. Crhr1−/− mice were resistant to diet-induced obesity and glucose intolerance. Restoring physiological circulating corticosterone levels abrogated molecular changes in adipocytes and the favorable phenotype of Crhr1−/− mice.
Conclusions:
Our findings suggest the importance of the CRF2 pathway in the control of adipocyte plasticity. Increased CRF2 activity in adipocytes induces browning of WAT, differentiation of BAT and is associated with a favorable metabolic phenotype in mice lacking CRF1. Circulating corticosterone represses CRF2 activity in adipocytes and may thus regulate adipocyte physiology through the modulation of the local CRF/urocortin system. Targeting CRF receptor signaling specifically in the adipose tissue may represent a novel approach to tackle obesity
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