Pannexin 1 regulates postnatal neural stem and progenitor cell proliferation

<p>Abstract</p> <p>Background</p> <p>Pannexin 1 forms ion and metabolite permeable hexameric channels and is abundantly expressed in the brain. After discovering pannexin 1 expression in postnatal neural stem and progenitor cells we sought to elucidate its functional role in neuronal development.</p> <p>Results</p> <p>We detected pannexin 1 in neural stem and progenitor cells <it>in vitro</it> and <it>in vivo</it>. We manipulated pannexin 1 expression and activity in Neuro2a neuroblastoma cells and primary postnatal neurosphere cultures to demonstrate that pannexin 1 regulates neural stem and progenitor cell proliferation likely through the release of adenosine triphosphate (ATP).</p> <p>Conclusions</p> <p>Permeable to ATP, a potent autocrine/paracine signaling metabolite, pannexin 1 channels are ideally suited to influence the behavior of neural stem and progenitor cells. Here we demonstrate they play a robust role in the regulation of neural stem and progenitor cell proliferation. Endogenous postnatal neural stem and progenitor cells are crucial for normal brain health, and their numbers decline with age. Furthermore, these special cells are highly responsive to neurological injury and disease, and are gaining attention as putative targets for brain repair. Therefore, understanding the fundamental role of pannexin 1 channels in neural stem and progenitor cells is of critical importance for brain health and disease.</p

p-type Bi2Se3 for topological insulator and low temperature thermoelectric applications

The growth and elementary properties of p-type Bi2Se3 single crystals are reported. Based on a hypothesis about the defect chemistry of Bi2Se3, the p-type behavior has been induced through low level substitutions (1 percent or less) of Ca for Bi. Scanning tunneling microscopy is employed to image the defects and establish their charge. Tunneling and angle resolved photoemission spectra show that the Fermi level has been lowered into the valence band by about 400 meV in Bi1.98Ca0.02Se3 relative to the n-type material. p-type single crystals with ab plane Seebeck coefficients of +180 microVK-1 at room temperature are reported. These crystals show a giant anomalous peak in the Seebeck coefficient at low temperatures, reaching +120 microVK-1 at 7 K, giving them a high thermoelectric power factor at low temperatures. In addition to its interesting thermoelectric properties, p-type Bi2Se3 is of substantial interest for studies of technologies and phenomena proposed for topological insulators.Comment: v2: STM characterization of n and p type Bi2Se3 is adde

Thermoelectric transport in Bi2Te3/Sb2Te3\text{Bi}_2\text{Te}_3/\text{Sb}_2\text{Te}_3 superlattices

The thermoelectric transport properties of $\text{Bi}_2\text{Te}_3/\text{Sb}_2\text{Te}_3$superlattices are analyzed on the basis of first-principles calculations and semi-classical Boltzmann theory. The anisotropy of the thermoelectric transport under electron and hole-doping was studied in detail for different superlattice periods at changing temperature and charge carrier concentrations. A clear preference for thermoelectric transport under hole-doping, as well as for the in-plane transport direction was found for all superlattice periods. At hole-doping the electrical transport anisotropies remain bulk-like for all investigated systems, while under electron-doping quantum confinement leads to strong suppression of the cross-plane thermoelectric transport at several superlattice periods. In addition, insights on the Lorenz function, the electronic contribution to the thermal conductivity and the resulting figure of merit are given

The development of ferromagnetism in the doped topological insulator Bi2-xMnxTe3

The development of ferromagnetism in Mn-doped Bi2Te3 is characterized through measurements on a series of single crystals with different Mn content. Scanning tunneling microscopy analysis shows that the Mn substitutes on the Bi sites, forming compounds of the type Bi2-xMnxTe3, and that the Mn substitutions are randomly distributed, not clustered. Mn doping first gives rise to local magnetic moments with Curie-like behavior, but by the compositions Bi1.96Mn0.04Te3 and Bi1.91Mn0.09Te3 a second order ferromagnetic transition is observed, with Tc ~ 9-12 K. The easy axis of magnetization in the ferromagnetic phase is perpendicular to the Bi2Te3 basal plane. Thermoelectric power and Hall effect measurements show that the Mn-doped Bi2Te3 crystals are p-type. Angle resolved photoemission spectroscopy measurements show that the topological surface states that are present in pristine Bi2Te3 are also present in ferromagnetic Mn-doped Bi2-xMnxTe3, and that the dispersion relations of the surface states are changed in a subtle fashion

Structural, Vibrational, and Electronic Study of α‑As2Te3 under Compression

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry C, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/acs.jpcc.6b06049We report a study of the structural, vibrational, and electronic properties of layered monoclinic arsenic telluride (α-As2Te3) at high pressures. Powder X-ray diffraction and Raman scattering measurements up to 17 GPa have been complemented with ab initio total-energy, lattice dynamics, and electronic band structure calculations. Our measurements, which include previously unreported Raman scattering measurements for crystalline α-As2Te3, show that this compound undergoes a reversible phase transition above 14 GPa at room temperature. The monoclinic crystalline structure of α-As2Te3 and its behavior under compression are analyzed by means of the compressibility tensor. Major structural and vibrational changes are observed in the range between 2 and 4 GPa and can be ascribed to the strengthening of interlayer bonds. No evidence of any isostructural phase transition has been observed in α-As2Te3. A comparison with other group 15 sesquichalcogenides allows understanding the structure of α-As2Te3 and its behavior under compression based on the activity of the cation lone electron pair in these compounds. Finally, our electronic band structure calculations show that α-As2Te3 is a semiconductor at 1 atm, which undergoes a trivial semiconducting−metal transition above 4 GPa. The absence of a pressure-induced electronic topological transition in α-As2Te3 is discussed.This work has been performed under financial support from Projects MAT2013-46649-C4-2-P, MAT2013-46649-C4-3-P, MAT2015-71070-REDC, FIS2013-48286-C2-1-P, and FIS2013-48286-C2-2-P of the Spanish Ministry of Economy and Competitiveness (MINECO), and the Department of Education, Universities and Research of the Basque Government and UPV/EHU (Grant No. IT756-13). This publication is also fruit of "Programa de Valoracion y Recursos Conjuntos de I+D+i VLC/CAMPUS" and has been financed by the Spanish Ministerio de Educacion, Cultura y Deporte as part of "Programa Campus de Excelencia Internacional" through Projects SP20140701 and SP20140871. Finally, authors thank ALBA Light Source for beam allocation at beamline MSPD.Cuenca Gotor, VP.; Sans-Tresserras, JÁ.; Ibáñez, J.; Popescu, C.; Gomis, O.; Vilaplana Cerda, RI.; Manjón Herrera, FJ.... (2016). Structural, Vibrational, and Electronic Study of α‑As2Te3 under Compression. Journal of Physical Chemistry C. 120(34):19340-19352. https://doi.org/10.1021/acs.jpcc.6b06049S19340193521203

An integrative review of the factors influencing older nurses’ timing of retirement

Aims: To summarise the international empirical literature to provide a comprehensive understanding of older nurses’ decision making surrounding the timing of their retirement. Background: The global nursing shortage is increasing. Amongst some countries it has become an economic imperative to consider raising the state pension age and to extend working lives. Design: An integrative literature review using an integrated design. Data sources: MEDLINE, CINAHL and Business Source Premier databases were searched for studies between January 2007 ‐ October 2019. Review Methods: Quality appraisal of the studies were conducted. Findings were summarised, grouped into categories and themes extracted. Two models were developed for data representation. Results: 132 studies were identified by the search strategy. Of these, 27 articles were included for appraisal and synthesis. 16 papers were quantitative, seven qualitative and four mixed methods. The research took place in 13 different geographical locations. Most studies were of a questionnaire design, followed by interviews and focus groups. The total participant sample was 35,460. Through a synthesis of the studies, four themes were identified: Health, Well‐being and Family factors; Employer factors; Professional factors; Financial factors. Conclusion: This review revealed the heterogeneity of studies on this subject and confirmed previous findings but also established a ranking of criteria that influences nurses’ decision making: age, followed by personal and organisational factors. Four extracted themes of push and pull factors map onto these factors. No ‘one‐size‐fits‐all’ strategy exists to ensure the extension of older nurses’ working lives. Organisations need to foster an environment where older nurses feel respected and heard and where personal and professional needs are addressed

Organizational configuration of hospitals succeeding in attracting and retaining nurses

Organizational configuration of hospitals succeeding in attracting and retaining nurses. This paper contrasts structural and managerial characteristics of low- and high-turnover hospitals, and describes the organizational configuration of attractive hospitals. In countries facing nurse shortages and turnover, some hospitals succeed in recruiting and retaining nurses. In Magnet Hospitals, managerial practices and environmental characteristics increase nurses\u2019 job satisfaction and their commitment to the organization, which in turn decreases nurse turnover. Such an approach suggests that organizations are best understood as clusters of interconnected structures and practices, i.e. organizational configurations rather than entities whose components can be understood in isolation. From a sample of 12 hospitals whose nurse turnover was studied for 1 year, structural and organizational features of hospitals in the first and fourth quartiles, i.e. attractive (turnover11\uc68%) were contrasted. A questionnaire, including perceptions of health-related factors, job demands, stressors, work schedules, organizational climate, and work adjustments antecedent to turnover, was received from 401 nurses working in attractive hospitals (response rate - 53\uc68%) and 774 nurses in conventional hospitals (response rate \ubc 54\uc65%). Structural characteristics did not differentiate attractive and conventional hospitals, but employee perceptions towards the organization differed strikingly. Differences were observed for risk exposure, emotional demands, role ambiguity and conflicts, work-family conflicts, effort-reward imbalance and the meaning of work, all in favour of attractive hospitals (P < 0.01). Relationships with nursing management, work ability and satisfaction with working time, handover shifts and schedules were also better in attractive hospitals (P < 0.001). Job satisfaction and commitment were higher in attractive hospitals, whereas burnout and intention to leave were lower (P < 0.001). Organizational characteristics are key factors in nurse attraction and retention. Nurses face difficulties in their work situations, but some hospitals are perceived as healthy organizations. The concept of attractive institutions could serve as a catalyst for improvement in nurses\u2019 work environments in Europe

Psychosocial work load and stress in the geriatric care

<p>Abstract</p> <p>Background</p> <p>Due to the decrease in informal care by family members and the demographic development, the importance of professional geriatric care will rise considerably. Aim of this study was to investigate the psychosocial workplace situation for employees in this profession.</p> <p>Methods</p> <p>The German version of the COPSOQ (Copenhagen Psychosocial Questionnaire) was used for the assessment of psychosocial factors at work. The instrument includes 22 scales and 3 single items concerning demands, control, stress, support, and strain.</p> <p>Results between two study groups of geriatric care were compared to each other as well as to employees in general hospital care and a general population mean (COPSOQ database).</p> <p>Statistical analysis included t-tests, ANOVA and multiple comparisons of means. Statistical significance (p < 0.01, two-tailed) and a difference of at least 5 points in mean values were defined as the relevant threshold.</p> <p>Results</p> <p>In total 889 respondents from 36 institutions took part in the study. 412 worked in Home Care (HC), 313 in Geriatric Nursing Homes (GNH), 164 in other professions (e.g. administration).</p> <p>Comparison between HC and GNH showed more favourable values for the first group for the most scales, e.g. lower quantitative and emotional demands and less work-privacy conflict, better possibilities for development etc. Compared to external values from the German COPSOQ database for general hospital care (N = 1.195) and the total mean across all professions, COPSOQ-total (N = 11.168), the results are again positive for HC workers on most of the scales concerning demands and social support. The only negative finding is the very low amount of social relations at work due to the obligation to work alone most of the time. Employees in GNH rate predictability, quality of leadership and feedback higher when compared to general hospital care and show some further favourable mean values compared to the COPSOQ mean value for all professions. A disadvantage for GNH is the high rating for job insecurity.</p> <p>A supplementary subgroup analysis showed that the degree of negative evaluation of psychosocial factors concerning demands was related to the amount of working hours per week and the number of on-call duties.</p> <p>Conclusions</p> <p>Compared to employees in general hospital care and the COPSOQ overall mean value across all professions, geriatric care employees and especially home care workers evaluate their psychosocial working situation more positive for most aspects. However, this seems partly due to the very high proportion of part-time workers. Critical results for the two study groups are the relatively high job insecurity in nursing homes and the lack of social relations for the HCrs.</p