488 research outputs found

    Early growth performances of various seed sources of black (Prunus serotina Erhr.) and wild cherry (Prunus avium L.) seedlings on low and high elevation sites in the western Black Sea Region of Turkey

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    The growth performances of one-year old seedlings of various black cherry (BC) and wild cherry (WC) seed sources (SSs) that were planted on low elevation sites (LES) and high elevation sites (HES) in the western Black Sea Region (BSR) of Turkey were assessed one and five years after planting (YAP). Significance between and within-species variations were found for seedling growth. On species basis, WC was superior to BC for seedling groundline diameter and height growth for the low elevation sites(LES) of one and five years after planting (YAP), whereas no substantial survival and growth differences were found between the species for the high elevation sites (HES) of five YAP. Generally, seedlings averaged a greater survival on the LES, when compared with those on the HES. Local WC SSs (Tefen, Yayla and Dirgine) demonstrated an enhanced seedling survival and growth on LES than the other SSs. Unlike the LES results, a collection of BC (Michigan 1 and Ukraine) and WC SSs (Dirgine, Germany, and Tefen) displayed the best seedling growth over five years. The HES seedlings frequently experienced diebacks and forking due to heavy snow fall and wildlife browsing. Selection of the local WC SSs was vital for the LES. However, BC SSs may present a potential for planting on the HES with harsher environmental conditions.Keywords: Black cherry, provenance test, seedling growth and survival, wild cherry

    Photoelectrochemical cells based on emeraldine base form of polyaniline

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    Photoelectrochemical cells (PECs) have been fabricated using the emeraldine base form of polyaniline (EB) as a photoactive material and Eu2+/Eu3+ redox couple in methanol as an electrolyte. A PEC with a structure: Glass/ITO/EB/electrolyte/Pt produces an open-circuit voltage (V OC) of -0.132 V and a short-circuit current (I SC) of 0.64 µA cm-2 under 50 mW cm-2 white light illumination from Xe lamp. In an effort to increase the photoresponse, a PEC with a structure: Glass/ITO/EB:Nc-TiO2/Electrolyte/Pt has been devised in which a composite film of EB and nanocrystalline TiO2 (Nc-TiO2) is used as a photoactive material. The cell shows a V OC of -0.205 V and an I SC of 105 µA cm-2 when illuminated under the same conditions

    Long-range potential fluctuations and 1/f noise in hydrogenated amorphous silicon

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    We present a microscopic theory of the low-frequency voltage noise (known as "1/f" noise) in micrometer-thick films of hydrogenated amorphous silicon. This theory traces the noise back to the long-range fluctuations of the Coulomb potential produced by deep defects, thereby predicting the absolute noise intensity as a function of the distribution of defect activation energies. The predictions of this theory are in very good agreement with our own experiments in terms of both the absolute intensity and the temperature dependence of the noise spectra.Comment: 8 pages, 3 figures, several new parts and one new figure are added, but no conceptual revision

    A snapshot of the organization and provision of primary care in Turkey

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    Contains fulltext : 96599.pdf (publisher's version ) (Open Access)BACKGROUND: This WHO study aimed to support Turkey in its efforts to strengthen the primary care (PC) system by implementing the WHO Primary Care Evaluation Tool (PCET). This article provides an overview of the organization and provision of primary care in Turkey. METHODS: The WHO Primary Care Evaluation Tool was implemented in two provinces (Bolu and Eskisehir) in Turkey in 2007/08. The Tool consists of three parts: a national questionnaire concerning the organisation and financing of primary care; a questionnaire for family doctors; and a questionnaire for patients who visit a family health centre. RESULTS: Primary care has just recently become an official health policy priority with the introduction of a family medicine scheme. Although the supply of family doctors (FDs) has improved, they are geographically uneven distributed, and nationwide shortages of primary care staff remain. Coordination of care could be improved and quality control mechanisms were lacking. However, patients were very satisfied with the treatment by FDs. CONCLUSIONS: The study provides an overview of the current state of PC in Turkey for two provinces with newly introduced family medicine, by using a structured approach to evaluate the essential functions of PC, including governance, financing, resource generation, as well as the characteristics of a "good" service delivery system (as being accessible, comprehensive, coordinated and continuous)

    Telomerase and pluripotency factors jointly regulate stemness in pancreatic cancer stem cells

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    To assess the role of telomerase activity and telomere length in pancreatic CSCs we used different CSC enrichment methods (CD133, ALDH, sphere formation) in primary patient-derived pancreatic cancer cells. We show that CSCs have higher telomerase activity and longer telomeres than bulk tumor cells. Inhibition of telomerase activity, using genetic knockdown or pharmacological inhibitor (BIBR1532), resulted in CSC marker depletion, abrogation of sphere formation in vitro and reduced tumorigenicity in vivo. Furthermore, we identify a positive feedback loop between stemness factors (NANOG, OCT3/4, SOX2, KLF4) and telomerase, which is essential for the self-renewal of CSCs. Disruption of the balance between telomerase activity and stemness factors eliminates CSCs via induction of DNA damage and apoptosis in primary patient-derived pancreatic cancer samples, opening future perspectives to avoid CSC-driven tumor relapse. In the present study, we demonstrate that telomerase regulation is critical for the “stemness” maintenance in pancreatic CSCs and examine the effects of telomerase inhibition as a potential treatment option of pancreatic cancer. This may significantly promote our understanding of PDAC tumor biology and may result in improved treatment for pancreatic cancer patientsThis research was funded by a Max Eder Fellowship of the German Cancer Aid (111746), a German Cancer Aid Priority Program ‘Translational Oncology’ 70112505, by a Collaborative Research Centre grant (316249678—SFB 1279) of the German Research Foundation, and by a Hector Foundation Cancer Research grant (M65.1) to P.C.H., B.S.J. is supported by a Rámon y Cajal Merit Award (RYC- 2012-12104) from the Ministerio de Economía y Competitividad, Spain and a Coordinated grant (GC16173694BARB) from the Fundación Asociación Española Contra el Cáncer (AECC). K.W. is supported by a Baustein 3.2 by Ulm University

    Functionalized Poly(3-hexylthiophene)s via Lithium–Bromine Exchange

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    Poly(3-hexylthiophene) (P3HT) is one of the most extensively investigated conjugated polymers and has been employed as the active material in many devices including field-effect transistors, organic photovoltaics and sensors. As a result, methods to further tune the properties of P3HT are desirable for specific applications. Herein, we report a facile postpolymerization modification strategy to functionalize the 4-position of commercially available P3HT in two simple steps–bromination of the 4-position of P3HT (Br–P3HT) followed by lithium−bromine exchange and quenching with an electrophile. We achieved near quantitative lithium–bromine exchange with Br–P3HT, which requires over 100 thienyl lithiates to be present on a single polymer chain. The lithiated-P3HT is readily combined with functional electrophiles, resulting in P3HT derivatives with ketones, secondary alcohols, trimethylsilyl (TMS) group, fluorine, or an azide at the 4-position. We demonstrated that the azide-modified P3HT could undergo Cu-catalyzed or Cu-free click chemistry, significantly expanding the complexity of the structures that can be appended to P3HT using this method.National Science Foundation (U.S.) (ECCS-0939514
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