415 research outputs found
A Cryogenic Test Station for the Pre-series 2400 W @ 1.8 K Refrigeration Units for the LHC
The cooling capacity below 2 K for the superconducting magnets in the Large Hadron Collider (LHC), at CERN, will be provided by eight refrigeration units at 1.8 K, each of them coupled to a 4.5 K refrigerator. The supply of the series units is linked to successful testing and acceptance of the pre-series delivered by the two selected vendors. To properly assess the performance of specific components such as cold compressors and some process specificities a dedicated test station is necessary. The test station is able to process up to 130 g/s between 4.5 & 20 K and aims at simulating the steady and transient operational modes foreseen for the LHC. After recalling the basic characteristics of the 1.8 K refrigeration units and the content of the acceptance tests of the pre-series, the principle of the test cryostat is detailed. The components of the test station and corresponding layout are described. The first testing experience is presented as well as preliminary results of the pre-series units
Male factor infertility and assisted reproductive technologies. indications, minimum access criteria and outcomes
BackgroundInfertility, which is defined as the inability to conceive after at least 12 months of regular unprotected sexual intercourses, affects about 15-20% of couples worldwide and a male factor is involved in about half of the cases. The development of assisted reproductive technology (ART) made it possible to conceive also to individuals affected from severe oligospermia or azoospermia. However, the impact of the male factor on embryo development, implantation, prevalence of chromosomal abnormalities, genetic and epigenetic alterations, and clinical and obstetric outcomes is still controversial.PurposeThis narrative review examines the indications, minimum access criteria, and outcomes by individual ART technique in relation to the male factor
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Commissioning the Cryogenic System of the First LHC Sector
The LHC machine, composed of eight sectors with superconducting magnets and accelerating cavities requires a complex cryogenic system providing high cooling capacities (18 kW equivalent at 4.5 K and 2.4  W at 1.8 K per sector produced in large cold boxes and distributed via 3.3-km cryogenic transfer lines). After individual reception tests of the cryogenic subsystems (cryogen storages, refrigerators, cryogenic transfer lines and distribution boxes) performed since 2000, the commissioning of the cryogenic system of the first LHC sector has been under way since November 2006. After a brief introduction to the LHC cryogenic system and its specificities, the commissioning is reported detailing the preparation phase (pressure and leak tests, circuit conditioning and flushing), the cool-down sequences including the handling of cryogenic fluids, the magnet powering phase and finally the warm-up. Preliminary conclusions on the commissioning of the first LHC sector will be drawn with the review of the critical points already solved or still pending. The last part of the paper reports on the first operational experience of the LHC cryogenic system in the perspective of the commissioning of the remaining LHC sectors and the beam injection test
Avoiding hot-spots in Microwave-Assisted Pd/C catalysed reactions by using the biomass derived solvent γ-Valerolactone
Herein, we report the use of γ-valerolactone as a new biomass-derived reaction medium for microwave assisted organic synthesis. The interaction of this solvent with microwaves and its heating profile under microwave irradiation has been fully characterized for the first time, demonstrating its stability and the applicability in microwave assisted Pd/C catalysed reactions avoiding the arcing phenomena frequently observed in these conditions. The use of γ-valerolactone demonstrated to be compatible with aliphatic and aromatic amines in the hydrogen transfer Pd/C mediated synthesis of benzimidazoles
Profiling Insulin Like Factor 3 (INSL3) Signaling in Human Osteoblasts
Abstract
BACKGROUND:
Young men with mutations in the gene for the INSL3 receptor (Relaxin family peptide 2, RXFP2) are at risk of reduced bone mass and osteoporosis. Consistent with the human phenotype, bone analyses of Rxfp2(-/-) mice showed decreased bone volume, alterations of the trabecular bone, reduced mineralizing surface, bone formation, and osteoclast surface. The aim of this study was to elucidate the INSL3/RXFP2 signaling pathways and targets in human osteoblasts.
METHODOLOGY/PRINCIPAL FINDINGS:
Alkaline phosphatase (ALP) production, protein phosphorylation, intracellular calcium, gene expression, and mineralization studies have been performed. INSL3 induced a significant increase in ALP production, and Western blot and ELISA analyses of multiple intracellular signaling pathway molecules and their phosphorylation status revealed that the MAPK was the major pathway influenced by INSL3, whereas it does not modify intracellular calcium concentration. Quantitative Real Time PCR and Western blotting showed that INSL3 regulates the expression of different osteoblast markers. Alizarin red-S staining confirmed that INSL3-stimulated osteoblasts are fully differentiated and able to mineralize the extracellular matrix.
CONCLUSIONS/SIGNIFICANCE:
Together with previous findings, this study demonstrates that the INSL3/RXFP2 system is involved in bone metabolism by acting on the MAPK cascade and stimulating transcription of important genes of osteoblast maturation/differentiation and osteoclastogenesis
Commissioning of the cryogenics of the LHC long straight sections
The LHC is made of eight circular arcs interspaced with eight Long Straight
Sections (LSS). Most powering interfaces to the LHC are located in these
sections where the particle beams are focused and shaped for collision,
cleaning and acceleration. The LSSs are constituted of several unique cryogenic
devices and systems like electrical feed-boxes, standalone superconducting
magnets, superconducting links, RF cavities and final focusing superconducting
magnets. This paper presents the cryogenic commissioning and the main results
obtained during the first operation of the LHC Long Straight Sections.Comment: 8 pp. Cryogenic Engineering Conference and International Cryogenic
Materials Conference, 28 Jun - 2 Jul 2009. Tucson, Arizon
FSH treatment improves sperm DNA damage in men with idiopathic infertility carriers of the FSH receptor p.N680S homozygous N genotype: an interim analysis
Study question: To assess whether in men with idiopathic infertility, the sperm DNA fragmentation (sDF) improves depending on the FSH receptor (FSHR) genotype as assessed by the non-synonymous polymorphisms (SNP) rs6166 (wild type or p.N680S).
Summary answer: FSH treatment improves sDF in a subgroup of idiopathic infertile men, although 40% of these men do not show any significant improve- ment. The response of sDF, a surrogate marker of sperm quality, together with the evaluation of FSHR SNP p.N680S might be useful to predict the response to FSH treatment.
What is known already: FSH is fundamental for spermatogenesis and is em- pirically used to treat male idiopathic infertility. Several studies suggest that sDF could be a candidate predictor of response to FSH treatment, in terms of probability to conceive. Furthermore, it is widely accepted that the FSHR SNP p.N680S influences ovarian response in women and testicular volume in men. Study design, size, duration: Multicenter, longitudinal, prospective, open-la- bel, two-arms clinical trial. Subjects enrolled were idiopathic infertile men and received 150 IU of recombinant FSH (Gonal f®) every other day for 12 weeks and were then followed-up for further 12 weeks after FSH-withdrawal. Patients were evaluated at baseline and at the end of the two phases. Participants/materials, setting, methods: Eighty-eight men with idiopathic male infertility carrier of the homozygous FSHR p.N680S N or S genotype, FSH 15%, were enrolled. 66 patients completed the sDF analysis. sDF was centrally evaluated by TUNEL/PI assay coupled to flow cy- tometry, resolving two different sperm populations, namely: PIbrighter and PIdimmer.
Main results and the role of chance: Thirty-seven men (56%) were carriers of the p.N680S homozygous-N and 29 (44%) of the homozygous-S genotype, respectively. Total sDF (PIbrighter + PIdimmer) was significantly lower at the end of the study in patients carriers of the p.N680S-N allele than patients carri- ers of p.N680S-S allele (p = 0.008). Only in patients carriers of the p.N680S-N allele, total sDF decreased significantly from baseline to the end of the study (p = 0.021) and this decrease was entirely sustained by the sperm population containing vital sperms (i.e., PIbrighter fraction) (p = 0.008). PIdimmer frac- tion, including only non-vital sperms, was significantly higher in patients car- riers of the p.N680S-S allele than in carriers of N allele (p = 0.018). Total sDF was inversely related to total sperm number (p = 0.020) and progressive sperm motility (p = 0.014).
Limitations, reason for caution: The statistical power of the results obtained so far is 86.9%, with alpha-error 0.05. This is an interim-analysis.
Wider implications of the findings: The study suggests that FSH treatment induces a significant improvement of total sDF in men carriers of the p.N680S homozygous N allele. This sDF decrease awaits confirmation, since the study will be completed by June 2015.
Study funding/competing interest(s): Funding by commercial/corporate company(ies) – The study was supported by unrestricted grant by Merck Serono.
Trial registration number: EudraCT number 2010-020240-35.
Keywords: FSH treatment, male infertility, Sperm-DNA fragmentatio
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Tissue Proteome of 2-Hydroxyacyl-CoA Lyase Deficient Mice Reveals Peroxisome Proliferation and Activation of ω-Oxidation
Peroxisomal fatty acid α-oxidation is an essential pathway for the degradation of β-carbon methylated fatty acids such as phytanic acid. One enzyme in this pathway is 2-hydroxyacyl CoA lyase (HACL1), which is responsible for the cleavage of 2-hydroxyphytanoyl-CoA into pristanal and formyl-CoA. Hacl1 deficient mice do not present with a severe phenotype, unlike mice deficient in other α-oxidation enzymes such as phytanoyl-CoA hydroxylase deficiency (Refsum disease) in which neuropathy and ataxia are present. Tissues from wild-type and Hacl1−/− mice fed a high phytol diet were obtained for proteomic and lipidomic analysis. There was no phenotype observed in these mice. Liver, brain, and kidney tissues underwent trypsin digestion for untargeted proteomic liquid chromatography-mass spectrometry analysis, while liver tissues also underwent fatty acid hydrolysis, extraction, and derivatisation for fatty acid gas chromatography-mass spectrometry analysis. The liver fatty acid profile demonstrated an accumulation of phytanic and 2-hydroxyphytanic acid in the Hacl1−/− liver and significant decrease in heptadecanoic acid. The liver proteome showed a significant decrease in the abundance of Hacl1 and a significant increase in the abundance of proteins involved in PPAR signalling, peroxisome proliferation, and omega oxidation, particularly Cyp4a10 and Cyp4a14. In addition, the pathway associated with arachidonic acid metabolism was affected; Cyp2c55 was upregulated and Cyp4f14 and Cyp2b9 were downregulated. The kidney proteome revealed fewer significantly upregulated peroxisomal proteins and the brain proteome was not significantly different in Hacl1−/− mice. This study demonstrates the powerful insight brought by proteomic and metabolomic profiling of Hacl1−/− mice in better understanding disease mechanism in fatty acid α-oxidation disorders
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