140 research outputs found
The Spectroscopic Orbits of Three Double-lined Eclipsing Binaries: I. BG Ind, IM Mon, RS Sgr
We present the spectroscopic orbit solutions of three double-lines eclipsing
binaries, BG Ind, IM Mon and RS Sgr. The first precise radial velocities (RVs)
of the components were determined using high resolution echelle spectra
obtained at Mt. John University Observatory in New Zealand. The RVs of the
components of BG Ind and RS Sgr were measured using Gaussian fittings to the
selected spectral lines, whereas two-dimensional cross-correlation technique
was preferred to determine the RVs of IM Mon since it has relatively short
orbital period among the other targets and so blending of the lines is more
effective. For all systems, the Keplerian orbital solution was used during the
analysis and also circular orbit was adopted because the eccentricities for all
targets were found to be negligible. The first precise orbit analysis of these
systems gives the mass ratios of the systems as 0.894, 0.606 and 0.325,
respectively for BG Ind, IM Mon and RS Sgr. Comparison of the mass ratio
values, orbital sizes and minimum masses of the components of the systems
indicates that all systems should have different physical, dynamical and
probable evolutionary status.Comment: 17 pages, 6 figures and 4 tables, accepted for publication in New
Astronom
Energy-efficient vertical handover parameters, classification and solutions over wireless heterogeneous networks: a comprehensive survey
In the last few decades, the popularity of wireless networks has been growing dramatically for both home and business networking. Nowadays, smart mobile devices equipped with various wireless networking interfaces are used to access the Internet, communicate, socialize and handle short or long-term businesses. As these devices rely on their limited batteries, energy-efficiency has become one of the major issues in both academia and industry. Due to terminal mobility, the variety of radio access technologies and the necessity of connecting to the Internet anytime and anywhere, energy-efficient handover process within the wireless heterogeneous networks has sparked remarkable attention in recent years. In this context, this paper first addresses the impact of specific information (local, network-assisted, QoS-related, user preferences, etc.) received remotely or locally on the energy efficiency as well as the impact of vertical handover phases, and methods. It presents energy-centric state-of-the-art vertical handover approaches and their impact on energy efficiency. The paper also discusses the recommendations on possible energy gains at different stages of the vertical handover process
Bi-allelic GAD1 variants cause a neonatal onset syndromic developmental and epileptic encephalopathy.
Developmental and epileptic encephalopathies are a heterogeneous group of early-onset epilepsy syndromes dramatically impairing neurodevelopment. Modern genomic technologies have revealed a number of monogenic origins and opened the door to therapeutic hopes. Here we describe a new syndromic developmental and epileptic encephalopathy caused by bi-allelic loss-of-function variants in GAD1, as presented by 11 patients from six independent consanguineous families. Seizure onset occurred in the first 2 months of life in all patients. All 10 patients, from whom early disease history was available, presented with seizure onset in the first month of life, mainly consisting of epileptic spasms or myoclonic seizures. Early EEG showed suppression-burst or pattern of burst attenuation or hypsarrhythmia if only recorded in the post-neonatal period. Eight patients had joint contractures and/or pes equinovarus. Seven patients presented a cleft palate and two also had an omphalocele, reproducing the phenotype of the knockout Gad1-/- mouse model. Four patients died before 4 years of age. GAD1 encodes the glutamate decarboxylase enzyme GAD67, a critical actor of the γ-aminobutyric acid (GABA) metabolism as it catalyses the decarboxylation of glutamic acid to form GABA. Our findings evoke a novel syndrome related to GAD67 deficiency, characterized by the unique association of developmental and epileptic encephalopathies, cleft palate, joint contractures and/or omphalocele
ATRAS: adaptive MAC protocol for efficient and fair coexistence between radio over fiber-based and CSMA/CA-based WLANs
A new hope for obesity management: Boron inhibits adipogenesis in progenitor cells through the Wnt/β-catenin pathway
© 2017Obesity is a worldwide medical problem resulting in serious morbidity and mortality involving differentiation of pre-adipocytes into mature adipocytes (adipogenesis). Boron treatment has been reported to be associated with weight reduction in experimental animals; however, its effects on pre-adipocyte differentiation and anti-adipogenic molecular mechanisms are unknown. In this study, we demonstrate the inhibitory activities of boric acid (BA) and sodium pentaborate pentahydrate (NaB) on adipogenesis using common cellular models. Boron treatment repressed the expression of adipogenesis-related genes and proteins, including CCAAT-enhancer-binding protein α and peroxisome proliferator-activated receptor γ, by regulating critical growth factors and the β-catenin, AKT, and extracellular signal-regulated kinase signaling pathways. In addition, although boron treatment did not induce apoptosis in pre-adipocytes, it depressed mitotic clonal expansion by regulation of cell cycle genes. Overall, these data offer promising insights into the prevention/treatment of obesity and associated diseases
CLP1 Founder Mutation Links tRNA Splicing and Maturation to Cerebellar Development and Neurodegeneration
SummaryNeurodegenerative diseases can occur so early as to affect neurodevelopment. From a cohort of more than 2,000 consanguineous families with childhood neurological disease, we identified a founder mutation in four independent pedigrees in cleavage and polyadenylation factor I subunit 1 (CLP1). CLP1 is a multifunctional kinase implicated in tRNA, mRNA, and siRNA maturation. Kinase activity of the CLP1 mutant protein was defective, and the tRNA endonuclease complex (TSEN) was destabilized, resulting in impaired pre-tRNA cleavage. Germline clp1 null zebrafish showed cerebellar neurodegeneration that was rescued by wild-type, but not mutant, human CLP1 expression. Patient-derived induced neurons displayed both depletion of mature tRNAs and accumulation of unspliced pre-tRNAs. Transfection of partially processed tRNA fragments into patient cells exacerbated an oxidative stress-induced reduction in cell survival. Our data link tRNA maturation to neuronal development and neurodegeneration through defective CLP1 function in humans
Genes for hereditary sensory and autonomic neuropathies: a genotype–phenotype correlation
Hereditary sensory and autonomic neuropathies (HSAN) are clinically and genetically heterogeneous disorders characterized by axonal atrophy and degeneration, exclusively or predominantly affecting the sensory and autonomic neurons. So far, disease-associated mutations have been identified in seven genes: two genes for autosomal dominant (SPTLC1 and RAB7) and five genes for autosomal recessive forms of HSAN (WNK1/HSN2, NTRK1, NGFB, CCT5 and IKBKAP). We performed a systematic mutation screening of the coding sequences of six of these genes on a cohort of 100 familial and isolated patients diagnosed with HSAN. In addition, we screened the functional candidate gene NGFR (p75/NTR) encoding the nerve growth factor receptor. We identified disease-causing mutations in SPTLC1, RAB7, WNK1/HSN2 and NTRK1 in 19 patients, of which three mutations have not previously been reported. The phenotypes associated with mutations in NTRK1 and WNK1/HSN2 typically consisted of congenital insensitivity to pain and anhidrosis, and early-onset ulcero-mutilating sensory neuropathy, respectively. RAB7 mutations were only found in patients with a Charcot-Marie-Tooth type 2B (CMT2B) phenotype, an axonal sensory-motor neuropathy with pronounced ulcero-mutilations. In SPTLC1, we detected a novel mutation (S331F) corresponding to a previously unknown severe and early-onset HSAN phenotype. No mutations were found in NGFB, CCT5 and NGFR. Overall disease-associated mutations were found in 19% of the studied patient group, suggesting that additional genes are associated with HSAN. Our genotype–phenotype correlation study broadens the spectrum of HSAN and provides additional insights for molecular and clinical diagnosis
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