Studies of intercellular Ca2+ signaling and gap-junction coupling in the developing cochlea of mouse models affected by congenital hearing loss

Connexin 26 (Cx26) and connexin 30 (Cx30) form gap junction channels that allow the intercellular diffusion of the Ca2+ mobilizing second messenger IP3. They also form hemichannels that release ATP from the endolymphatic surface of cochlear supporting and epithelial cells. Released ATP in turn activates G-protein coupled P2Y2 and P2Y4 receptors, PLC-dependent generation of IP3, release of Ca2+ from intracellular stores, permitting the regenerative propagation of intercellular Ca2+ signals. In the course of this work, we found that cochlear non-sensory cells of the greater and lesser epithelial ridge (GER and LER, respectively) share the same PLC- and IP3R-dependent signal transduction cascade activated by ATP. In addition, we demonstrated that ATP-dependent Ca2+ signaling activity in cochlear non-sensory cells is spatially graded from the apex to the base of the cochlea during the first postnatal week. Ca2+ signaling under these conditions depends on inositol-1,4,5-trisphosphate generation from phospholipase C (PLC)-dependent hydrolysis of PI(4,5)P(2). Thus we analyzed mice with defective expression of PIPKIγ and found that (i) this enzyme is essential for the acquisition of hearing; (ii) it is primarily responsible for the synthesis of the receptor-regulated PLC-sensitive PI(4,5)P(2) pool in the cell syncytia that supports auditory hair cells and; (iii) spatially graded impairment of the PIP2-IP3-Ca2+ signaling pathway in cochlear non-sensory cells affects the level of gap junction coupling. Vice versa, we found defective gap junction coupling and intercellular IP3-dependent Ca2+ signaling the cochlea of mice with targeted ablation Cx26 or Cx30, as well as in mice knock in for a point mutation (Cx30T5M) associated with human congenital deafness. Altogether, our findings link bidirectionally defective hearing acquisition to Ca2+ signaling impairment and decreased biochemical coupling in the developing cochlea. Transduction of connexin deficient cochlear cultures with a bovine adeno associated virus vectors encoding Cx26 or Cx30 restored protein expression, rescued both gap junction coupling and Ca2+ signaling. Based on this work, we conclude that in vivo connexin gene delivery to the inner ear is a route worth exploring to rescue hearing function in mouse models of deafness and, in future, may lead to the development of therapeutic interventions in humans

Heavy metals partioning in three French forest soils by sequential extraction procedure

To know the concentration of heavy metal associated to chemical compounds is important to evaluate the environmental risks on soils, particularly regarding ion bioavailability. The relative mobility and strength of binding of heavy metals to the soil components can be studied using a sequential extraction procedure which provides a meaningful comparison between different soil profiles. The heavy metals partitioning bas been identified in three different french forest soils : one cambic podzol, one calcaric cambisol and one mollic andosol, using a new sequential extraction method. Results show that metal fractionation is metal and site specific. The water leaching phase does not contain any metals. The proportion of heavy metal leached in the exchangeable and the acid — soplhuabslee is significant for Cd. The residual phase is important for Cr, Pb, and to a lesser extend for Ni. The organic matter fraction is dominant for Zn and Cu. Thus, the considered heavy metals are mainly bounded to iron oxides, to the organic matter and to the mineral residue. The order of heavy metals availability in the three soils would be : Zn>Cd>Cu>Pb>NiL&egatd;C r.i sotopes in some extracts of the extraction procedure corroborate the anthropogenic inputs for two soils. These both infomations allow to trace the origin, the mobility and the distribution of Pb in the soil

Strengths and Challenges of Distance Learning Modalities in the New Normal: Basis for Intervention Program

The study was conducted to identify the strengths and challenges of distance learning modalities as a basis for intervention programs from a memorial high school in a schools’ division in Bulacan, Philippines. The researcher used a descriptive survey type of study. For the sample of the study, it employed eight (8) teachers and 39 learners from a junior high school chosen randomly. A self-made checklist survey questionnaire was created by the researcher which was validated by a panel of experts. Descriptive statistics were used to analyze the collected data with the help of a Microsoft Excel sheet. Results revealed that teachers and learners have a variety of strengths in distance learning modalities. In addition, teachers and learners also stressed the different challenges they encountered for distance learning modalities. Based on these findings of the study, the researcher used them for a possible formulation of an intervention program that aimed to providing solutions for the challenges of distance learning and also enhancing the strengths for both the teachers and learners

An Examination of Consent and Experiences of Sexual Violence Among Queer and Transgender People in Atlanta

INTRODUCTION: Sexual and gender minorities (SGM) experience much higher rates of sexual violence compared to the general population but have been repeatedly overlooked in sexual violence and consent research highlighting the importance of understanding how SGM conceptualize consent and understand their experiences of sexual violence. METHODS: This study was exploratory in nature and utilized a qualitative research design. Data were collected via semi-structured interviews with queer and transgender adults (N=20) between the age of 18 and 30 who reside in Atlanta and have experienced sexual violence. Thematic content analysis was completed using NVivo 12. RESULTS: Participants described similar but distinct definitions and practices of consent that were mostly consistent with the literature. Participants shared the ways lack of knowledge or misunderstanding of consent, influenced by rape myths, affected how they viewed and responded to their experiences of sexual violence. The recreation of heteronormative gender dynamics in queer relationships, masculine gender expression as a protective factor for sexual violence, and the safety of mutual understanding and support in queer community were discussed in findings specific to queerness and consent. DISCUSSION: For many participants, because of societal conceptions of sexual violence, it took years to acknowledge and confront the trauma they experienced, delayed their seeking of support and services, and affected how they approached their future sexual encounters. To adequately address the needs and experiences of this community, sexual violence intervention and prevention efforts must attend to the unique factors that affect sexual and gender minority people who have survived sexual violence

Estimation of the distance and the properties of open clusters with Gaia

Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2017, Tutor: Xavier LuriThe purpose of this research work is to determine the distance and the properties of several open clusters using the Tycho-Gaia Astrometric Solution (TGAS) of the first Gaia Data Release. We have analysed the problem of the membership selection and the data collection using TGAS and the information in other catalogues. We have studied the properties of different clusters using a membership selection done by van Leeuwen (2017) and using the Palmer et al. (2015) algorithm to derive the different properties of the clusters. We have also compared our results with previous values from the bibliography for the studied clusters

Visual awareness negativity and P3: ERP study of the distinctive neural correlates of conscious vision

This research aimed to replicate the previous findings of Koivisto & Grassini (2016). Using event-related potentials (ERPs), we studied the neural correlates of visual consciousness. Specifically, we wanted to study visual awareness negativity, that has been reported as the first ERP correlate of consciousness as its latency seems to be fast enough to be the neural correlate of the phenomenal consciousness, which could be the earliest manifestation of consciousness. We also studied the late positivity, that seems to reflect the cognitive components of the reflective consciousness, as it involves the voluntary operations performed with the object like identify it or recognize it. Surprisingly, and despite the previously reported in literature, in this study we did not observe visual awareness negativity, but found that only late positivity correlated with conscious perception. We conclude that our results do not support the hypothesis about VAN as the correlate of phenomenal consciousness, whilst our observations regarding P3 appear to support the hypothesis about reflective consciousness occurring in this period. We interpret these findings as possibly affected by a different statistical analysis. Also, the fact that phenomenal consciousness can be understood in various ways may lead to contradictory findings. However, more research is necessary to find alternative explanations to our findings as well as other experimental approaches to the study of neural correlates of consciousness

Critical loads for lead in France: First results on forest soils

Within the framework of the United Nation Convention on Long Range Transboundary Air Pollution, France is part of the Working Group on Effect which aims at evaluating the impact of atmospheric deposition on ecosystems by calculating critical loads. The critical loads are the highest deposition of compounds that will not cause chemical changes in soil leading to long-term harmful effects on ecosystem structure and function. A guidance manual for calculation of critical loads for heavy metals (lead and cadmium) has been proposed by the Coordination Center for Effects (executive body of the WGE). French National Focal Center (CNRS and ADEME) aims in this study at evaluating the accuracy of the european methodology for calculation of critical loads for french forest soils. It appears that critical load approach is adapted for France but need to be calibrated at least for calculation of weathering fluxes and determination of critical limits. Stand-still on the contrary is not adequate because of inherent contradictions in the method and too much uncertainties in the transfer functions