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  • 1
    Online Resource
    Online Resource
    Springer Science and Business Media LLC ; 2013
    In:  Oecologia Vol. 172, No. 1 ( 2013-5), p. 271-278
    In: Oecologia, Springer Science and Business Media LLC, Vol. 172, No. 1 ( 2013-5), p. 271-278
    Type of Medium: Online Resource
    ISSN: 0029-8549 , 1432-1939
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2013
    detail.hit.zdb_id: 1462019-4
    detail.hit.zdb_id: 123369-5
    SSG: 12
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  • 2
    In: Advanced Engineering Materials, Wiley
    Abstract: The density functional theory (DFT) is applied to systematically investigate the geometrical structure, electronic, mechanical, vibrational, and optical properties of double perovskite Rb 2 LiTlF 6 in its cubic phase. To the best of one's knowledge, many physical properties of this compound are still not well established or not yet investigated; such as phonon properties, mechanical behavior, thermal properties, and so on. In this work, the stability of Rb 2 LiTlF 6 is explored by looking at its thermodynamical behavior through calculation of formation energy, cohesive energy, Goldschmidt tolerance factor, and phonon dispersion. Its mechanical properties are examined based on various characterization descriptors such as the independent elastic coefficients, bulk, shear, and Young's modulus, ratios such as Pugh and Poisson's, Kleinnman parameter, Zener anisotropy factor, Debye temperature, and melting temperature. Sound velocity in this material is predicted from the values of the bulk and shear modulus obtained. Thermal expansion coefficient at finite temperatures are obtained using the approach of quasi‐harmonic approximation. Its electronic property is also investigated using generalized gradient approximation and also hybrid functionals. At a later stage, its optical behavior upon the effect of light excitation is explored using the many body pertubation theory approximation. Having envisioned this material as a wide band gap semiconductor, it can be useful in numerous applications such as designing the top‐cell of tandem photovoltaic configuration, photodetection, and light emitting diodes. It is strongly believed that this work will provide a helpful guidance for future experimental and theoretical investigations of this material.
    Type of Medium: Online Resource
    ISSN: 1438-1656 , 1527-2648
    Language: English
    Publisher: Wiley
    Publication Date: 2024
    detail.hit.zdb_id: 2016980-2
    detail.hit.zdb_id: 1496512-4
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  • 3
    Online Resource
    Online Resource
    IOP Publishing ; 2022
    In:  Materials Research Express Vol. 9, No. 9 ( 2022-09-01), p. 095901-
    In: Materials Research Express, IOP Publishing, Vol. 9, No. 9 ( 2022-09-01), p. 095901-
    Abstract: The most popular semiconductor in dye-sensitized solar cells (DSSCs) is titanium dioxide (TiO 2 ) because of its low cost, non-toxicity, and good stability. However, the DSSCs still have low efficiency due to the low light absorption of TiO 2 in the visible region. Understanding the properties of TiO 2 can contribute to improving the efficiency of DSSCs. In this study, we use density functional theory to investigate the electronic and optical properties of TiO 2 brookite (210) surface mono-doped and co-doped with 4 d transition metals, silver, and molybdenum. Our results show that the band gap energy of brookite (210) surface is 3.514 eV, which reduces to 1.143 eV and 0.183 eV when doped with Ag and Mo, respectively. However, doping with both Ag and Mo yielded a band gap of 0.387 eV. The results suggest the presence of Ag and Mo 4 d states below the conduction band minimum, which could be responsible for the narrowing of the band gap on the brookite (210) surface. Both mono-doped and co-doped brookite (210) surfaces have higher visible light absorbance compared to the undoped brookite (210) surface and extend to the near-infrared region.
    Type of Medium: Online Resource
    ISSN: 2053-1591
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 2760382-9
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  • 4
    Online Resource
    Online Resource
    International Journal of Innovative Research & Development (GlobeEdu) ; 2023
    In:  The International Journal of Business & Management ( 2023-08-18)
    In: The International Journal of Business & Management, International Journal of Innovative Research & Development (GlobeEdu), ( 2023-08-18)
    Abstract: This study investigated the influence of collective bargaining on organizational performance in tea factories managed by KTDA. The Kenyan tea industry faces numerous challenges that have impacted its overall performance and one potential explanation that has gained increased attention is the role of trade unions in enhancing the industry's fortunes. The study determined the relationship between Organizational Performance and Collective Bargaining. A Descriptive Survey design was adopted to conduct the study in the sixty-six (66) tea factories managed by the KTDA, which operates in all the tea-growing regions within Kenya. The factories were categorized into seven strata based on their regional location, and a sample size of 30% was randomly drawn from each stratum. This resulted in a total of 23 factories being selected for the study. Thereafter, the Human Resource and Administration Manager and Union Official were selected using purposive sampling, whereas Union Members were chosen randomly, resulting in three (3) respondents from each of the 23 sampled factories, totaling 69 respondents. Both primary and secondary data were used in this study, with primary data being collected using structured questionnaires. The questionnaires were tested and revised, and reliability was assessed, yielding a Cronbach's alpha coefficient of 0.786 that affirmed the reliability of the measure. The collected data underwent both descriptive and inferential statistical analysis. The analysis revealed that collective bargaining (Beta = 0.347, t = 3.296, p =0.002) had a significant positive effect on organizational performance. The study recommended that organizations should improve the quality of collective bargaining practices in the workplace for improved organizational performance.
    Type of Medium: Online Resource
    ISSN: 2321-8916
    Language: Unknown
    Publisher: International Journal of Innovative Research & Development (GlobeEdu)
    Publication Date: 2023
    detail.hit.zdb_id: 2739114-0
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  • 5
    In: The FASEB Journal, Wiley, Vol. 23, No. S1 ( 2009-04)
    Type of Medium: Online Resource
    ISSN: 0892-6638 , 1530-6860
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2009
    detail.hit.zdb_id: 1468876-1
    SSG: 12
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  • 6
    Online Resource
    Online Resource
    Association Marocaine pour l'Amelioration de la Qualite de l'Enseignement ; 2020
    In:  The Journal of Quality in Education Vol. 10, No. 16 ( 2020-11-11), p. 144-164
    In: The Journal of Quality in Education, Association Marocaine pour l'Amelioration de la Qualite de l'Enseignement, Vol. 10, No. 16 ( 2020-11-11), p. 144-164
    Abstract: Many stakeholders have expressed concern about the many graduates from Kenyan universities who after qualifying, not only fail to get jobs but also fail to venture into alternative forms of engagement to earn their livelihood, a scenario that raises question as to the quality and relevance of University education they got. The concerns being raised calls for rethinking of the quality and relevance of university education in Kenya. This study, therefore, sought to investigate the propensity of university education in Kenya to inculcate entrepreneurial culture in graduates. The theory of planned behaviour formed the theoretical foundation of the study. The study adopted a triangular design approach where views relating to entrepreneurial culture were sought from final year students from one public and one private university. The study targeted 3146 final year students drawn from University of Kabianga, (2272) and Kabarak University (874). From this, a sample of 614 students proportionately distributed among the two universities was drawn. Entrepreneurial environment was found to be more or less the same in both private and public universities recording moderate score. However, public university scored slightly higher. In conclusion, there is no significant difference in the levels of preference for entrepreneurship when comparison is made between public and private universities in Kenya. Arising from the current finding, the study recommends provision of better entrepreneurial support system.
    Type of Medium: Online Resource
    ISSN: 2028-1897
    URL: Issue
    Language: English
    Publisher: Association Marocaine pour l'Amelioration de la Qualite de l'Enseignement
    Publication Date: 2020
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  • 7
    Online Resource
    Online Resource
    American Scientific Publishers ; 2022
    In:  Materials Express Vol. 12, No. 1 ( 2022-01-01), p. 114-122
    In: Materials Express, American Scientific Publishers, Vol. 12, No. 1 ( 2022-01-01), p. 114-122
    Abstract: Harnessing solar energy with the help of cheaper, more abundant and environmentally-friendly materials is a major research thrust currently. Health hazards emanating from fossil fuel combustion, depletion of nonrenewable sources, global warming and environmental degradation are some of the push factors towards clean, non-toxic and environmentally friendly methods of producing electrical energy. To harvest solar energy, the Cu 2 ZnSnS 4 (CZTS) semiconductor is currently a foremost candidate, which can supply encouraging amounts of energy. Some of its advantages are the optical direct band gap and high absorption coefficients. In this study, CZTS is investigated as a material for solar cells using first principles method. Thus, structural, electronic and optical properties of pure CZTS and doped CZTS (1 1 2) surface were investigated using the DFT as implemented in the CASTEP code. Alkaline earth metals, calcium (Ca) and barium (Ba) were adsorbed on the CZTS (1 1 2) surface using the adsorption locator module. Our results suggest that doping with barium rather than calcium could improve the photocatalytic activity of the device.
    Type of Medium: Online Resource
    ISSN: 2158-5849
    Language: English
    Publisher: American Scientific Publishers
    Publication Date: 2022
    detail.hit.zdb_id: 2905325-0
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  • 8
    Online Resource
    Online Resource
    Wiley ; 2010
    In:  The FASEB Journal Vol. 24, No. S1 ( 2010-04)
    In: The FASEB Journal, Wiley, Vol. 24, No. S1 ( 2010-04)
    Type of Medium: Online Resource
    ISSN: 0892-6638 , 1530-6860
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2010
    detail.hit.zdb_id: 1468876-1
    SSG: 12
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  • 9
    In: Materials Express, American Scientific Publishers, Vol. 10, No. 7 ( 2020-10-01), p. 1127-1134
    Abstract: Hybrid perovskites are organometal halide materials that are attractive to the researchers owing to impressive physical properties like absorption coefficients. Controlled formation of perovskite crystal during the preparation process is key to achieving better morphological features, thereby influencing the material's properties. In this paper, we examined the impact of two synthesis techniques as well as new material composition on the properties of the perovskite materials. These perovskite materials were produced by one- and two-step solution processes and the kinetics of the composition of perovskite were characterized by the following techniques: UV-vis spectroscopy, X-ray diffraction (XRD) and Thermo gravimetric analysis. The electrochemical properties were examined by cyclic voltammetry using the two-electrode system. All samples exhibited an absorption onset around 850 nm which corresponded well with the energy gap (∼1.55 eV). The two-step process resulted in smooth XRD patterns, hence exhibiting improved crystallinity owing to sharper peaks than those from one-step process. The sample crystallite sizes ranged of 44–81 nm. We conclude that two synthesis techniques together with new materials composition showed better thermal stability compared with previous reports. Cyclic voltammetry indicated that the perovskite electrodes exhibited stable electrochemical performance and easy charge transfer during the reaction. Our results suggest better electrochemical properties with possible capacitance which is beneficial for energy storage devices.
    Type of Medium: Online Resource
    ISSN: 2158-5849
    Language: English
    Publisher: American Scientific Publishers
    Publication Date: 2020
    detail.hit.zdb_id: 2905325-0
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  • 10
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2009
    In:  Cancer Research Vol. 69, No. 14 ( 2009-07-15), p. 5743-5751
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 69, No. 14 ( 2009-07-15), p. 5743-5751
    Abstract: Aberrant signaling through G-protein coupled receptors promotes metastasis, the major cause of breast cancer death. We identified regulator of G-protein signaling 4 (RGS4) as a novel suppressor of breast cancer migration and invasion, important steps of metastatic cascades. By blocking signals initiated through Gi-coupled receptors, such as protease-activated receptor 1 and CXC chemokine receptor 4, RGS4 disrupted Rac1-dependent lamellipodia formation, a key step involved in cancer migration and invasion. RGS4 has GTPase-activating protein (GAP) activity, which inhibits G-protein coupled receptor signaling by deactivating G-proteins. An RGS4 GAP-deficient mutant failed to inhibit migration and invasion of breast cancer cells in both in vitro assays and a mouse xenograft model. Interestingly, both established breast cancer cell lines and human breast cancer specimens showed that the highest levels of RGS4 protein were expressed in normal breast epithelia and that RGS4 down-regulation by proteasome degradation is an index of breast cancer invasiveness. Proteasome blockade increased endogenous RGS4 protein to levels that markedly inhibit breast cancer cell migration and invasion, which was reversed by an RGS4-targeted short hairpin RNA. Our findings point to the existence of a mechanism for posttranslational regulation of RGS4 function, which may have important implications for the acquisition of a metastatic phenotype by breast cancer cells. Preventing degradation of RGS4 protein should attenuate aberrant signal inputs from multiple Gi-coupled receptors, thereby retarding the spread of breast cancer cells and making them targets for surgery, radiation, and immune treatment. [Cancer Res 2009;69(14):5743–51]
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2009
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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