146 research outputs found
On the concept of sloped motion for free-floating wave energy converters
A free-floating wave energy converter (WEC) concept whose power take-off (PTO) system reacts against water inertia is investigated herein. The main focus is the impact of inclining the PTO direction on the system performance. The study is based on a numerical model whose formulation is first derived in detail. Hydrodynamics coefficients are obtained using the linear boundary element method package WAMIT. Verification of the model is provided prior to its use for a PTO parametric study and a multi-objective optimization based on a multi-linear regression method. It is found that inclining the direction of the PTO at around 50. to the vertical is highly beneficial for the WEC performance in that it provides a high capture width ratio over a broad region of the wave period range
On the concept of sloped motion for free-floating wave energy converters
A free-floating wave energy converter (WEC) concept whose power take-off (PTO) system reacts against water inertia is investigated herein. The main focus is the impact of inclining the PTO direction on the system performance. The study is based on a numerical model whose formulation is first derived in detail. Hydrodynamics coefficients are obtained using the linear boundary element method package WAMIT. Verification of the model is provided prior to its use for a PTO parametric study and a multi-objective optimization based on a multi-linear regression method. It is found that inclining the direction of the PTO at around 50. to the vertical is highly beneficial for the WEC performance in that it provides a high capture width ratio over a broad region of the wave period range
Open chromatin encoded in DNA sequence is the signature of âmasterâ replication origins in human cells
For years, progress in elucidating the mechanisms underlying replication initiation and its coupling to transcriptional activities and to local chromatin structure has been hampered by the small number (approximately 30) of well-established origins in the human genome and more generally in mammalian genomes. Recent in silico studies of compositional strand asymmetries revealed a high level of organization of human genes around 1000 putative replication origins. Here, by comparing with recently experimentally identified replication origins, we provide further support that these putative origins are active in vivo. We show that regions âŒ300-kb wide surrounding most of these putative replication origins that replicate early in the S phase are hypersensitive to DNase I cleavage, hypomethylated and present a significant enrichment in genomic energy barriers that impair nucleosome formation (nucleosome-free regions). This suggests that these putative replication origins are specified by an open chromatin structure favored by the DNA sequence. We discuss how this distinctive attribute makes these origins, further qualified as âmasterâ replication origins, priviledged loci for future research to decipher the human spatio-temporal replication program. Finally, we argue that these âmasterâ origins are likely to play a key role in genome dynamics during evolution and in pathological situations
Hydroponic System: A Promising Biotechnology for Food Production and Wastewater Treatment
Several regions of the world are suffering from water scarcity and available water pollution. Mediterranean countries (such as Portugal, Spain, Italy, Greece, Tunisia, Israel, and Jordan) do not meet the requirements in terms of quantity that have been increasing in the last decades for the various sectors, due to lack of water resources, winters with low rainfalls, and summers with hot and dry conditions. Agriculture is the leading water-consuming sector (70%â80%), followed by industry and domestic use. However, industrial and domestic uses are considered priorities, conditioning the amount of accessible water for the agriculture sector. the use of reclaimed water should be considered in the integrated water management system to avoid damages to the environment (surface and underground water, soil, fauna, and flora) and public health. The use of wastewater for irrigation should be carefully investigated and planned in terms of proper treatment, treated wastewater quality, volume of treated wastewater used, application method, physicochemical characterization of soil, nutritional needs of plants, distance to existing water sources, risk of animal and human contamination, and others. Environmental and economic gains can be achieved by reusing wastewater if the study, planning, and application are performed in a sustainable basis.info:eu-repo/semantics/publishedVersio
Analysis of KLF transcription factor family gene variants in type 2 diabetes
<p>Abstract</p> <p>Background</p> <p>The KrĂŒppel-like factor (<it>KLF</it>) family consists of transcription factors that can activate or repress different genes implicated in processes such as differentiation, development, and cell cycle progression. Moreover, several of these proteins have been implicated in glucose homeostasis, making them candidate genes for involvement in type 2 diabetes (T2D).</p> <p>Methods</p> <p>Variants of nine <it>KLF </it>genes were genotyped in T2D cases and controls and analysed in a two-stage study. The first case-control set included 365 T2D patients with a strong family history of T2D and 363 normoglycemic individuals and the second set, 750 T2D patients and 741 normoglycemic individuals, all of French origin. The SNPs of six <it>KLF </it>genes were genotyped by Taqman<sup>Âź </sup>SNP Genotyping Assays. The other three <it>KLF </it>genes (KLF2, -15 and -16) were screened and the identified frequent variants of these genes were analysed in the case-control studies.</p> <p>Results</p> <p>Three of the 28 SNPs showed a trend to be associated with T2D in our first case-control set (P < 0.10). These SNPs, located in the <it>KLF2, KLF4 </it>and <it>KLF5 </it>gene were then analysed in our second replication set, but analysis of this set and the combined analysis of the three variants in all 2,219 individuals did not show an association with T2D in this French population. As the <it>KLF2</it>, -15 and -16 variants were representative for the genetic variability in these genes, we conclude they do not contribute to genetic susceptibility for T2D.</p> <p>Conclusion</p> <p>It is unlikely that variants in different members of the <it>KLF </it>gene family play a major role in T2D in the French population.</p
On the pulmonary toxicity of oxygen. 4. The thyroid arena
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Experimental and Molecular Pathology 92 (2012): 140-154, doi:10.1016/j.yexmp.2011.11.006.Normally developed thyroid function is critical to the transition from fetal to neonatal life with the
onset of independent thermoregulation, the most conspicuous of the many ways in which thyroid
secretions act throughout the body. A role for thyroid secretions in growth and maturation of the
lungs as part of the preparation for the onset of breathing has been recognized for some time but how
this contributes to tissue and cell processes and defenses under the duress of respiratory distress has
not been well examined. Extensive archival autopsy material was searched for thyroid and adrenal
weights, first by gestational age, and then for changes during the first hours after birth as ratios to
body weight. After a gestational age of 22 weeks the fetal thyroid and adrenal glands at autopsy in
those with hyaline membrane disease are persistently half the size of those in "normal" infants dying
with other disorders. When the thyroid is examined shortly after birth it reveals a post natal loss of
mass per body weight of similar orders of magnitude which does not occur in the control group. A
clinical sample of premature infants with (12) and without (14) hyaline membrane disease was
tested for T4, TSH, TBG, and total serum protein. The results also demonstrate a special subset with
lower birth weights at the same gestational age, and lower serum T4 and total serum protein. Ventilatory distress in newborn rabbits was induced by bilateral cervical vagotomy at 24 hours post
natal following earlier injection of thyroxine (T4) or thyroid stimulating hormone (TSH) and
comparisons were made with untreated animals and by dose. Early life thyroidectomy was
performed followed by exposure to either air or 100% oxygen. A final experiment in air was
vagotomy after thyroidectomy. Composite analysis of these methods indicates that thyroid factors
are both operative and important in the newborn animal with ventilatory distress. This work and
the archival data indicate those infants destined to develop hyaline membrane disease through
respiratory distress are a distinct developmental and clinical subset with the point of departure from
otherwise normal development and maturation in the second or early third trimester. This interval
is known to be a period of marked variation in the overview indicators of fetal progress through
gestational time. The initiating factor or circumstance which then separates this special subset from
normal future development is placed by these observations firmly into the period when human fetal
TSH dramatically rises 7-fold (17.5-25.5 weeks) followed by a lesser 3 to 4 fold increase in T4
which is extended into the early third trimester. The earlier part of this interval is characterized by
the thyrotrophic action of chorionic gonadotropin (hCG). The possibility that abnormalities in the
intrauterine environment secondary to maternal infection play a role within this time frame is
indicated by the demonstration that interleukin-2 (IL-2) induces an anterior pituitary release of
TSH. Since IL-2 has this property and is not an acute phase cytokine, some form of chronic
infection or an immunopathic process seems more likely as a possible active factor in pathogenesis.The work in this report was performed under a grant to the University of Chicago from the John A.
Hartford Foundation
Risques et adaptation nutritionnelle en cancérologie
This article starts with a presentation of Caycedian Sophrology. We then evaluate its impact on stress reduction through a questionnaire on a studentsâ population. It appears that stress level increases between the two sessions in the control group while it decreases in the experimental group
Replication Fork Polarity Gradients Revealed by Megabase-Sized U-Shaped Replication Timing Domains in Human Cell Lines
In higher eukaryotes, replication program specification in different cell types remains to be fully understood. We show for seven human cell lines that about half of the genome is divided in domains that display a characteristic U-shaped replication timing profile with early initiation zones at borders and late replication at centers. Significant overlap is observed between U-domains of different cell lines and also with germline replication domains exhibiting a N-shaped nucleotide compositional skew. From the demonstration that the average fork polarity is directly reflected by both the compositional skew and the derivative of the replication timing profile, we argue that the fact that this derivative displays a N-shape in U-domains sustains the existence of large-scale gradients of replication fork polarity in somatic and germline cells. Analysis of chromatin interaction (Hi-C) and chromatin marker data reveals that U-domains correspond to high-order chromatin structural units. We discuss possible models for replication origin activation within U/N-domains. The compartmentalization of the genome into replication U/N-domains provides new insights on the organization of the replication program in the human genome
Transcriptional Activation of the Adenoviral Genome Is Mediated by Capsid Protein VI
Gene expression of DNA viruses requires nuclear import of the viral genome. Human
Adenoviruses (Ads), like most DNA viruses, encode factors within early
transcription units promoting their own gene expression and counteracting
cellular antiviral defense mechanisms. The cellular transcriptional repressor
Daxx prevents viral gene expression through the assembly of repressive chromatin
remodeling complexes targeting incoming viral genomes. However, it has remained
unclear how initial transcriptional activation of the adenoviral genome is
achieved. Here we show that Daxx mediated repression of the immediate early Ad
E1A promoter is efficiently counteracted by the capsid protein VI. This requires
a conserved PPxY motif in protein VI. Capsid proteins from other DNA viruses
were also shown to activate the Ad E1A promoter independent of Ad gene
expression and support virus replication. Our results show how Ad entry is
connected to transcriptional activation of their genome in the nucleus. Our data
further suggest a common principle for genome activation of DNA viruses by
counteracting Daxx related repressive mechanisms through virion proteins
DMTs and Covid-19 severity in MS: a pooled analysis from Italy and France
We evaluated the effect of DMTs on Covid-19 severity in patients with MS, with a pooled-analysis of two large cohorts from Italy and France. The association of baseline characteristics and DMTs with Covid-19 severity was assessed by multivariate ordinal-logistic models and pooled by a fixed-effect meta-analysis. 1066 patients with MS from Italy and 721 from France were included. In the multivariate model, anti-CD20 therapies were significantly associated (OR = 2.05, 95%CI = 1.39â3.02, p < 0.001) with Covid-19 severity, whereas interferon indicated a decreased risk (OR = 0.42, 95%CI = 0.18â0.99, p = 0.047). This pooled-analysis confirms an increased risk of severe Covid-19 in patients on anti-CD20 therapies and supports the protective role of interferon
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