Comparative study on hydrogen issues of biphenyl/diphenyl oxide and polydimethylsiloxane heat transfer fluids

The formation of hydrogen from new and several used qualities of eutectic biphenyl (BP) and diphenyl oxide (DPO) mixture was investigated with an established lab experiment in the range of 380 – 410 °C and 410 – 430 °C respectively. Kinetic evaluations show that hydrogen formation increases not only with temperature but also with time. Field samples extracted after 5 and 10 years’ operating time confirm an increase of hydrogen formation with operating. A thermal aging study at 430 °C for 480 hours with a series of samples composed of new BP/DPO each doped with a degradation product indicates that the formation of phenol is the mayor driving factor for steadily increase with time. The impact of hydrogen formation on the concentration in the fluids of parabolic trough systems was checked with a simplified model that takes volumetric dimensions, residence time at maximum temperature, back mixing with fluid from overflow vessels and some assumed hydrogen removal step into account. New BP/DPO at 400 °C and polydimethylsiloxane (PDMS) at 425 °C is compared. After initially higher formation of hydrogen, in the long term low hydrogen formation is reported for PDMS. Although PDMS is considered at significantly higher operating temperature lower hydrogen concentrations are to be expected for this fluid after a starting-up phase in the model system. Accordingly, hydrogen control with PDMS is expected to be easier with PDMS fluids like HELISOL® 5A as no steady increase of effort on hydrogen removal will be required

Loss of Cx43 in Murine Sertoli Cells Leads to Altered Prepubertal Sertoli Cell Maturation and Impairment of the Mitosis-Meiosis Switch.

Male factor infertility is a problem in today's society but many underlying causes are still unknown. The generation of a conditional Sertoli cell (SC)-specific connexin 43 (Cx43) knockout mouse line (SCCx43KO) has provided a translational model. Expression of the gap junction protein Cx43 between adjacent SCs as well as between SCs and germ cells (GCs) is known to be essential for the initiation and maintenance of spermatogenesis in different species and men. Adult SCCx43KO males show altered spermatogenesis and are infertile. Thus, the present study aims to identify molecular mechanisms leading to testicular alterations in prepubertal SCCx43KO mice. Transcriptome analysis of 8-, 10- and 12-day-old mice was performed by next-generation sequencing (NGS). Additionally, candidate genes were examined by qRT-PCR and immunohistochemistry. NGS revealed many significantly differentially expressed genes in the SCCx43KO mice. For example, GCspecific genes were mostly downregulated and found to be involved in meiosis and spermatogonial differentiation (e.g., Dmrtb1, Sohlh1). In contrast, SC-specific genes implicated in SC maturation and proliferation were mostly upregulated (e.g., Amh, Fshr). In conclusion, Cx43 in SCs appears to be required for normal progression of the first wave of spermatogenesis, especially for the mitosis-meiosis switch, and also for the regulation of prepubertal SC maturation

Left-Dominant Temporal-Frontal Hypercoupling in Schizophrenia Patients With Hallucinations During Speech Perception

International audienceBackground: Task-based functional neuroimaging studies of schizophrenia have not yet replicated the increased coordinated hyperactivity in speech-related brain regions that is reported with symptom-capture and resting-state studies of hallucinations. This may be due to suboptimal selection of cognitive tasks. Methods: In the current study, we used a task that allowed experimental manipulation of control over verbal material and compared brain activity between 23 schizophrenia patients (10 hallucinators, 13 nonhallucinators), 22 psychiatric (bipolar), and 27 healthy controls. Two conditions were presented, one involving inner verbal thought (in which control over verbal material was required) and another involving speech perception (SP; in which control verbal material was not required). Results: A functional connectivity analysis resulted in a left-dominant temporal-frontal network that included speech-related auditory and motor regions and showed hypercoupling in past-week hallucinating schizophrenia patients (relative to nonhallucinating patients) during SP only. Conclusions: These findings replicate our previous work showing generalized speech-related functional network hypercoupling in schizophrenia during inner verbal thought and SP, but extend them by suggesting that hypercoupling is related to past-week hallucination severity scores during SP only, when control over verbal material is not required. This result opens the possibility that practicing control over inner verbal thought processes may decrease the likelihood or severity of hallucinations

Cross-Kingdom RNAi of Pathogen Effectors Leads to Quantitative Adult Plant Resistance in Wheat

Cross-kingdom RNA interference (RNAi) is a biological process allowing plants to transfer small regulatory RNAs to invading pathogens to trigger the silencing of target virulence genes. Transient assays in cereal powdery mildews suggest that silencing of one or two effectors could lead to near loss of virulence, but evidence from stable RNAi lines is lacking. We established transient host-induced gene silencing (HIGS) in wheat, and demonstrate that targeting an essential housekeeping gene in the wheat powdery mildew pathogen (Blumeria graminis f. sp. tritici) results in significant reduction of virulence at an early stage of infection. We generated stable transgenic RNAi wheat lines encoding a HIGS construct simultaneously silencing three B.g. tritici effectors including SvrPm3(a1/f1), a virulence factor involved in the suppression of the Pm3 powdery mildew resistance gene. We show that all targeted effectors are effectively downregulated by HIGS, resulting in reduced fungal virulence on adult wheat plants. Our findings demonstrate that stable HIGS of effector genes can lead to quantitative gain of resistance without major pleiotropic effects in wheat

Essential and recurrent roles for hairpin RNAs in silencing \u3ci\u3ede novo sex\u3c/i\u3e chromosome conflict in \u3ci\u3eDrosophila simulans\u3c/i\u3e

Meiotic drive loci distort the normally equal segregation of alleles, which benefits their own transmission even in the face of severe fitness costs to their host organism. However, relatively little is known about the molecular identity of meiotic drivers, their strategies of action, and mechanisms that can suppress their activity. Here, we present data from the fruitfly Drosophila simulans that address these questions. We show that a family of de novo, protamine- derived X-linked selfish genes (the Dox gene family) is silenced by a pair of newly emerged hairpin RNA (hpRNA) small interfering RNA (siRNA)-class loci, Nmy and Tmy. In the w[XD1] genetic background, knockout of nmy derepresses Dox and MDox in testes and depletes male progeny, whereas knockout of tmy causes misexpression of PDox genes and renders males sterile. Importantly, genetic interactions between nmy and tmy mutant alleles reveal that Tmy also specifically maintains male progeny for normal sex ratio. We show the Dox loci are functionally polymorphic within D. simulans, such that both nmy-associated sex ratio bias and tmy-associated sterility can be rescued by wild-type X chromosomes bearing natural deletions in different Dox family genes. Finally, using tagged transgenes of Dox and PDox2, we provide the first experimental evidence Dox family genes encode proteins that are strongly derepressed in cognate hpRNA mutants. Altogether, these studies support a model in which protamine-derived drivers and hpRNA suppressors drive repeated cycles of sex chromosome conflict and resolution that shape genome evolution and the genetic control of male gametogenesis

Silent voices of the midwives: factors that influence midwives’ achievement of successful neonatal resuscitation in sub-Saharan Africa: a narrative inquiry

Background: In Tanzania, birth asphyxia is a leading cause of neonatal death. The aim of this study was to identify factors that influence successful neonatal resuscitation to inform clinical practice and reduce the incidence of very early neonatal death (death within 24 h of delivery). Methods: This was a qualitative narrative inquiry study utilizing the 32 consolidated criteria for reporting qualitative research (COREQ). Audio-recorded, semistructured, individual interviews with midwives were conducted. Thematic analysis was applied to identify themes. Results: Thematic analysis of the midwives’ responses revealed three factors that influence successful resuscitation: 1. Hands-on training ('HOT') with clinical support during live emergency neonatal resuscitation events, which decreases fear and enables the transfer of clinical skills; 2. Unequivocal commitment to the Golden Minute® and the mindset of the midwife; and. 3. Strategies that reduce barriers. Immediately after birth, live resuscitation can commence at the mother’s bedside, with actively guided clinical instruction. Confidence and mastery of resuscitation competencies are reinforced as the physiological changes in neonates are immediately visible with bag and mask ventilation. The proclivity to perform suction initially delays ventilation, and suction is rarely clinically indicated. Keeping skilled midwives in labor wards is important and impacts clinical practice. The midwives interviewed articulated a mindset of unequivocal commitment to the baby for one Golden Minute®. Heavy workload, frequent staff rotation and lack of clean working equipment were other barriers identified that are worthy of future research. Conclusions: Training in resuscitation skills in a simulated environment alone is not enough to change clinical practice. Active guidance of 'HOT' real-life emergency resuscitation events builds confidence, as the visible signs of successful resuscitation impact the midwife’s beliefs and behaviors. Furthermore, a focused commitment by midwives working together to reduce birth asphyxia-related deaths builds hope and collective self-efficacy

Monitoring Water Diversity and Water Quality with Remote Sensing and Traits

Changes and disturbances to water diversity and quality are complex and multi-scale in space and time. Although in situ methods provide detailed point information on the condition of water bodies, they are of limited use for making area-based monitoring over time, as aquatic ecosystems are extremely dynamic. Remote sensing (RS) provides methods and data for the cost-effective, comprehensive, continuous and standardised monitoring of characteristics and changes in characteristics of water diversity and water quality from local and regional scales to the scale of entire continents. In order to apply and better understand RS techniques and their derived spectral indicators in monitoring water diversity and quality, this study defines five characteristics of water diversity and quality that can be monitored using RS. These are the diversity of water traits, the diversity of water genesis, the structural diversity of water, the taxonomic diversity of water and the functional diversity of water. It is essential to record the diversity of water traits to derive the other four characteristics of water diversity from RS. Furthermore, traits are the only and most important interface between in situ and RS monitoring approaches. The monitoring of these five characteristics of water diversity and water quality using RS technologies is presented in detail and discussed using numerous examples. Finally, current and future developments are presented to advance monitoring using RS and the trait approach in modelling, prediction and assessment as a basis for successful monitoring and management strategies.This research received no external funding.Peer Reviewe