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Intramuscular connective tissue (IMCT) is mainly composed of several fibrils (known as total collagen (TCol)) linked between each other by different chemical cross-links (CLs), the whole being embedded in a matrix of proteoglycans (PGs). In the field of beef quality, there is limited information on the role of CLs and PGs. Accordingly, several authors suggest that, to investigate the role of IMCT, it is important to investigate them just like TCol and insoluble collagen (ICol). In muscle, there are two other components, the muscle fibres and intramuscular fat (IMF) content. There are limited data on the relationships between these three components of muscle and then on possibility to independently manipulate these characteristics in order to control the final quality of meat. The present study aimed to investigate whether consistent relationships exist between these different components of muscle. Therefore, the present study compared four muscles of two cattle types (dairy and beef) to determine associations between TCol, ICol, CLs and PGs. Data were analysed across and within muscle (M) and animal type (AT) based on residuals. There was a strong M and AT effect for all muscle characteristics and an interaction M × AT for type I muscle fibres and IMF. Correlations between TCol, ICol and their CLs were M- and AT-independent. Total proteoglycans were positively correlated with TCol and ICol in a muscle-dependent manner irrespective of AT, but no correlation was found with CLs. On the contrary, CLs were negatively correlated with the ratio TPGs : TCol in an M-dependent manner, irrespective of AT. TCol, ICol and CLs were positively and negatively correlated with type IIA and IIB+X muscle fibres only in longissimus thoracis (LT) muscle, regardless the AT. Insoluble collagen was the only parameter of IMCT to be correlated with type I muscle fibres but only in LT muscle, irrespective of AT. There was no correlation between PGs and muscle fibre types, but PGs were the only IMCT component to be related with IMF in an M-dependent manner, irrespective of AT. Finally, there was no correlation between muscle fibre types and IMF content within M and AT. This study revealed that there is a strong relationship between IMCT components irrespective of M, an M-dependent relationship between the IMCT components and muscle fibre types and few (only with PGs) or no relationship between IMF and IMCT and muscle fibres.
Introduction: Tourniquets are a mainstay of hemorrhage management. However, there is insufficient evidence to guide device sselection. This review analyses the literature on tourniquets, for the following outcomes: lower-extremity arterial hemostasis, application speed, and pain. Methods: Studies were limited to English. Non-human studies, case series, and intra-operative applications were excluded. A systematic review of MEDLINE, PubMed, Google Scholar, and the Cochrane Database from 1992 to Dec 2017 was performed. Article citations were also assessed. Results: Twenty-one studies met criteria, testing 28 tourniquet devices. The most popular devices for arterial hemostasis were the Combat Application Tourniquet (C-A-T) (662 applications), Special Operations Forces Tactical Tourniquet (SOFTT) (307 applications), blood pressure cuff (80 applications), rubber tubing (58 applications) and the Emergency Medical Tourniquet (EMT) (52 applications). The blood pressure cuff achieved the highest (weighted averages) rate of 99% (95% CI 93 to 100) based on four studies of 80 applications. Followed by the EMT which achieved 83% (95% CI 72 to 93), based on three studies of 52 applications (p<0.01). The fastest device to apply, taking 17 seconds (95% CI 11 to 23), was surgical tubing, based on two studies totalling 30 applications. The next fastest was the blood pressure cuff, requiring 20 seconds (95% CI 18 to 22), based on two studies totaling 58 applications (though there was no statistical difference in application time, p=0.08). Tolerance could not be analyzed, due to heterogeneity of outcome measures. Conclusion: This is the first meta-analysis of tourniquet outcomes. The literature lacks a standard approach to device application. The quality of evidence is of very low due to the small sample sizes, lack of blinding, selective outcome reporting and result inconsistency. Common medical equipment appear to outperform commercial tourniquets for arterial hemostasis and speed of application; however, they are some of the least studied devices.
Band ogives are a striking and enigmatic feature of Mer de Glace glacier flow. The surface mass balances (SMBs) of these ogives have been thoroughly investigated over a period of 12 years. We find similar cumulative SMBs over this period, ranging between −64.1 and −66.2 m w.e., on the dark and light ogives even though the dark ogive albedo is ~40% lower than that of the light ogives. We, therefore, looked for another process that could compensate for the large difference of absorbed short-wave radiation between dark and light ogives. Based on in situ roughness measurements, our numerical modeling experiments demonstrate that a significant difference in turbulent flux over the dark and light ogives due to different surface roughnesses could compensate for the difference in radiative forcing. Our results discard theories for the genesis of band ogives that are based on the assumption of a strong ice ablation contrast between dark and light ogives. More generally, our study demonstrates that future roughness changes are as important to analyze as the radiative impacts of a potential increase of aerosols or debris at the surface of glaciers.
Bacteraemia caused by Escherichia coli are particularly frequent and severe, contrasting with the commensal character of the strains found in the digestive tract. A better understanding of the relationships between strains of both origins is needed to unravel the pathogenesis of this disease. Two hundred and forty-three commensal strains were compared to 243 bacteraemic strains isolated from adult hosts matched in terms of gender and age, and from similar location and epoch. Phylogenetic grouping, O-type determination, virulence factor content and antibiotic resistance were compared. Compared to commensal strains, the bacteraemic strains were characterized by a higher proportion of B2, C and D phylogroups, and a lower proportion of A, E and F phylogroups. They also had a lower proportion of the B2 subgroup IV (STc141), a higher proportion of virulence factors, and a higher frequency of antibiotic resistance. These differences were more marked for the bacteraemic strains of urinary tract origin with the presence of specific clones, whereas the bacteraemic strains of digestive origin remained non-significantly different from the commensal strains, except for their antibiotic resistance. Thus, two levels of specialization from commensal strains were demonstrated in the bacteraemic strains: resistance to antibiotics in all cases, and virulence for those of urinary tract origin.
This paper is devoted to the definition, analysis and implementation of semi-Lagrangian methods as they result from particle methods combined with remeshing. We give a complete consistency analysis of these methods, based on the regularity and momentum properties of the remeshing kernels, and a stability analysis of a large class of second and fourth order methods. This analysis is supplemented by numerical illustrations. We also describe a general approach to implement these methods in the context of hybrid computing and investigate their performance on GPU processors as a function of their order of accuracy.
The aim of this paper was to identify pre-slaughter factors that modify total and insoluble collagen contents in bovine muscle to construct a model of collagen dynamics. The meta-analyses were performed with primary data of total (n = 1165) and insoluble (n = 1145) collagen contents from INRA experiments obtained from different muscles in young bulls, cows and steers. According to both the bibliography and meta-analyses, total collagen content and solubility were greatly affected by the muscle (type). Moreover, the pattern of the evolution of collagen characteristics was similar among Longissimus, Semitendinosus and Triceps brachii muscles in young bulls. In cows, collagen contents in the Triceps brachii muscle had delayed dynamics compared with the other muscles. Collagen characteristics differed among breeds because of variation in the maturity of the breed. Similarly, according to the meta-analyses, total and insoluble collagen content evolutions with the degree of maturity (DOM; proportion of adult weight reached at slaughter) were different in dairy and rustic breeds from those of beef breeds, especially in bulls. Although the relationships between collagen content and DOM were quantified in different muscles and sexes, the precision of the fitted equations was not sufficient for prediction. Consequently, relying on the hypotheses raised by the meta-analysis and the literature, an approach to further develop a dynamic mechanistic model of soluble and insoluble collagen content is proposed.
The Franco-Algerian Monitor of Solar Images (MISOLFA) was developped in order to study
the effect of optical turbulence on diameter measurements from ground-based solar
observations. Some first results obtained with MISOLFA are presented.
This study reports the metabolic and morphological characteristics of bovine intermuscular adipose tissue (AT) throughout foetal growth. Our hypothesis was that the histological and molecular features of intermuscular AT would be different from those previously reported for foetal perirenal AT, based on its anatomical location near the muscle and the recent identification of two distinct adipocyte precursors in mouse AT depending on their locations. To address this question, intermuscular AT was sampled from Charolais and Blond d'Aquitaine foetuses at 180, 210 and 260 days post conception (dpc). The two bovine breeds were chosen because of the higher adiposity of Charolais than Blond d'Aquitaine cattle during the postnatal life. Regardless of the breed, adipocyte volume increased slightly (+38%, P < 0.01) with increasing foetal age. This was concomitant with a decrease (P < 0.05) in the activity of enzymes involved in de novo fatty acid (FA) synthesis (FA synthase and glucose-6-phosphate dehydrogenase) and FA esterification (glycerol-3-phosphate dehydrogenase) when expressed per million adipocytes, and with an increase (P ⩽ 0.01) in mRNA abundances for uncoupling protein 1, adiponectin and leptin (LEP) between 180 and 260 dpc. No difference was observed in the adipocyte volume between breeds, which was consistent with the lack of major between-breed differences in mRNA abundances or activities of enzymes involved in lipid metabolism. The mRNA abundance of lipoprotein lipase was maintained across ages, suggesting a storage of circulating FA rather than of FA synthesized de novo. Plasma LEP increased with foetal age, but only in the Charolais breed (+71%, P ⩽ 0.01), and was two- to threefold higher in Charolais than Blond d'Aquitaine foetuses. Regardless of the breed, bovine intermuscular AT contained predominantly unilocular adipocytes believed to be white adipocytes that were larger at 260 dpc than at 180 dpc. These data thus challenge current concepts of the largely brown nature of bovine foetal AT (based on histological and metabolic features of perirenal AT as previously reported a few days before or after birth).
Some proteins have been revealed as biomarkers for beef tenderness by previous studies. These markers could be used in immunological tests to predict beef tenderness, in living animals as well as in carcasses. It is well known that rearing practices modify the amounts of mRNA and proteins. Therefore, the reliability of protein tests could be affected by livestock and biological effects such as production systems, breed, muscle and animal type. This study analysed the effects of animal and muscle type on 24 proteins. The animals studied were 67 young bulls and 44 steers of the Charolais breed, and muscles were Longissimus thoracis and Semitendinosus. Protein amounts were determined by Dot blot, an immunological technique. Results showed that expressions of 20 proteins were influenced by animal and/or muscle type. These results could lead to modifications and adaptations of prediction tests according to rearing practice, bovine breed and beef cut.
We have recently shown that the expression of the DNAJA1 gene encoding a heat shock protein (Hsp40) is a negative marker of meat tenderness in Charolais bulls. To acquire knowledge on the regulation of DNAJA1 expression, we analysed the abundance of DNAJA1 transcripts and protein during development and according to management factors (e.g. feeding treatments, growth path and stress status) in different bovine muscles during postnatal life. We report here a developmental expression profile for DNAJA1 with decreased levels of transcript and protein during the progression of myogenesis. During postnatal life, we found the highest expression of DNAJA1 in the most oxidative muscles. No effect was detected for dietary treatment (pasture v. maize-based diet), growth path (compensatory growth after a restriction period) or pre-slaughter stress status. Therefore, the genetic background and muscle type could be considered as the main factors regarding the level of DNAJA1. Integration of the knowledge gained from this study should help to predict muscle metabolic properties and the ability of the live animals to give high sensory quality meat.
Selective breeding is an effective tool to improve livestock. Several selection experiments have been conducted to study direct selection responses as well as correlated responses in traits of skeletal muscle growth and function. Moreover, comparisons of domestic with wild-type species and of extreme breeds provide information on the genetic background of the skeletal muscle phenotype. Structural muscular components that differed with increasing distance in lean growth or meat quality in mammals were found to be myofibre number, myofibre size, proportions of fibre types as well as the numbers and proportions of secondary and primary fibres. Furthermore, markers of satellite cell proliferation, metabolic enzyme activities, glycogen and fat contents, the expression of myosin heavy chain isoforms, of activated AMPKα and other proteins in skeletal muscle tissue and circulating IGF1 and IGF-binding proteins have been identified to be involved in selection responses observed in pigs, cattle and/or chicken. The use of molecular methods for selective breeding of fish has only recently been adopted in aquaculture and studies of the genetic basis of growth and flesh quality traits are scarce. Some of the molecular markers of muscle structure/metabolism in livestock have also been identified in fish, but so far no studies have linked them with selection response. Genome scans have been applied to identify genomic regions exhibiting quantitative trait loci that control traits of interest, for example, muscle structure and meat quality in pigs and growth rate in chicken. As another approach, polymorphisms in candidate genes reveal the relationship between genetic variation and target traits. Thus, in large-scale studies with pigs’ associations of polymorphisms in the HMGA2, CA3, EPOR, NME1 and TTN genes with traits of carcass and meat quality were detected. Other studies revealed the significance of mutations in the IGF2 and RYR1 genes for carcass lean and muscle fibre traits in pigs. Mutations in the myostatin (MSTN) gene in fish were also examined. Advances in research of the genetic and environmental control of traits related to meat quality and growth have been made by the application of holistic ‘omics’ techniques that studied the whole muscle-specific genome, transcriptome and proteome in relation to muscle and meat traits, the development of new methods for muscle fibre typing and the adaptation of biophysical measures to develop parameters of muscle fibre traits as well as the application of in vitro studies. Finally, future research priorities in the field are defined.
Skeletal muscle development in vertebrates – also termed myogenesis – is a highly integrated process. Evidence to date indicates that the processes are very similar across mammals, poultry and fish, although the timings of the various steps differ considerably. Myogenesis is regulated by the myogenic regulatory factors and consists of two to three distinct phases when different fibre populations appear. The critical times when myogenesis is prone to hormonal or environmental influences depend largely on the developmental stage. One of the main mechanisms for both genetic and environmental effects on muscle fibre development is via the direct action of the growth hormone–insulin-like growth factor (GH–IGF) axis. In mammals and poultry, postnatal growth and function of muscles relate mainly to the hypertrophy of the fibres formed during myogenesis and to their fibre-type composition in terms of metabolic and contractile properties, whereas in fish hyperplasia still plays a major role. Candidate genes that are important in skeletal muscle development, for instance, encode for IGFs and IGF-binding proteins, myosin heavy chain isoforms, troponin T, myosin light chain and others have been identified. In mammals, nutritional supply in utero affects myogenesis and the GH–IGF axis may have an indirect action through the partitioning of nutrients towards the gravid uterus. Impaired myogenesis resulting in low skeletal myofibre numbers is considered one of the main reasons for negative long-term consequences of intrauterine growth retardation. Severe undernutrition in utero due to natural variation in litter or twin-bearing species or insufficient maternal nutrient supply may impair myogenesis and adversely affect carcass quality later in terms of reduced lean and increased fat deposition in the progeny. On the other hand, increases in maternal feed intake above standard requirement seem to have no beneficial effects on the growth of the progeny with myogenesis not or only slightly affected. Initial studies on low and high maternal protein feeding are published. Although there are only a few studies, first results also reveal an influence of nutrition on skeletal muscle development in fish and poultry. Finally, environmental temperature has been identified as a critical factor for growth and development of skeletal muscle in both fish and poultry.
Contractile and metabolic properties of bovine muscles play an important role in meat sensorial quality, particularly tenderness. Earlier studies based on Myosin heavy chain isoforms analyses and measurements of glycolytic and oxidative enzyme activities have demonstrated that the third trimester of foetal life in bovine is characterized by contractile and metabolic differentiation. In order to complete this data and to obtain a precise view of this phase and its regulation, we performed a proteomic analysis of Semitendinosus muscle from Charolais foetuses analysed at three stages of the third trimester of gestation (180, 210 and 260 days). The results complete the knowledge of important changes in the profiles of proteins from metabolic and contractile pathways. They provide new insights about proteins such as Aldehyde dehydrogenase family, Enolase, Dihydrolipoyl dehydrogenase, Troponin T or Myosin light chains isoforms. These data have agronomical applications not only for the management of beef sensorial quality but also in medical context, as bovine myogenesis appears very similar to human one.
Systematic crosses between various strains of Drosophila melanogaster lead in some cases to partly sterile F1 females (SF females). Two main classes of strain, inducer and reactive, have been denned on the basis of this sterility, which shows very specific physiological features. SF females arise only when reactive females are crossed with inducer males. In contrast, F1 females (RSF) produced by the reciprocal cross between inducer females and reactive males have normal fertility. All wild populations tested are of the inducer category, laboratory strains are either inducer or reactive. Sterility is the result of interaction between two genetic factors denoted I and R, respectively responsible for the inducer and reactive conditions and whose unusual genetic behaviour has been described in other papers. The present paper reports experiments showing that the I–R interaction is also responsible for high levels of X nondisjunction and of mutation in the SF female germ-line. The analogy with the P-M system of Kidwell, Kidwell & Sved (1977b), is discussed as are also the implications of the existence of the I-R system for spontaneous mutation research in D. melanogaster.
Nançay radio astronomy station teams are involved in several aspects of the Research and Development (R&D)
for radio astronomy detectors and systems:
i) Microelectronics: Low Noise Amplifiers (LNA), receiver on chip and
system in package. The long-term goal is to provide sub-systems for
the future Square Kilometer Array and its Pathfinders. A beamformer chip has been integrated
in the FP6 SKADS dense aperture array technology demonstrator EMBRACE. Wide band SiGe LNAs are
developed, beamformers with in-chip control are studied and more
complex integrated receivers are designed for the european Aperture Array
Verification Programme demonstrator.
ii) Digital signal processing: EMBRACE beamforming has been implemented
in the digital backend and RFI-mitigation oriented
signal processing has been designed for realtime systems,
including work for FP6 SKADS and FP7 PrepSKA.
iii) A study of Phased Array Feeds has started in 2008, in order to study
the radio electric properties of PAFs at the focus of large F/D
telescopes, such as the Nançay Radio Telescope, as well as to test PAF
systems in collaboration with the SPP/IRFU and LAL/IN2P3 laboratories.
Muscle contractile and metabolic characteristics were studied on nine cloned and eight non-cloned (control) heifers. The animals were submitted to repeated biopsies of the semitendinosus (ST) muscle at the ages of 8, 12, 18 and 24 months. The contractile type was determined from the proportion of the different myosin heavy chain (MyHC) isoforms separated by electrophoresis. Glycolytic metabolism was assessed by lactate dehydrogenase (LDH) activity, and oxidative metabolism was assessed by isocitrate dehydrogenase (ICDH), cytochrome-c oxidase (COX) and β-hydroxyacyl-CoA dehydrogenase (HAD) activities. In cloned heifers at 8 months of age, there was a greater proportion of MyHC I (slow oxidative isoform) and MyHC IIa (fast oxido-glycolytic isoform), a lower proportion of MyHC IIx (fast glycolytic isoform), greater COX and HAD activity and a lower LDH/ICDH ratio compared with control heifers. Thus, young cloned heifers had slower muscle types associated with a more oxidative muscular metabolism than control heifers. From 12 months of age onwards, no significant differences were observed between cloned and control heifers. A delay in muscle differentiation and maturation in cloned heifers is hypothesised and discussed.