Molten Salt Electrolytes for Electrodeposition of CdTe Films

We report preliminary investigation of several molten salt electrolytes containing CdCl2 and TeCl4 for the electrodeposition of CdTe films at temperatures well above (\u3e250 °C) those used with aqueous and organic electrolytes. These high temperatures have potential todramatically increase the crystallite size (Poole, Engelken, et al., 1994), as is important for optoelectronic device applications of CdTe, a leading II-VIsemiconductor. This paper willsurvey the results obtained withelectrolytes such as B2O,/HBO2 (m.p. - 230\u27C), NaCH3COO (m.p. » 324°C), ZnCl2 (m.p. - 283*C), and LiCl/KCl (m.p. * 350 °C), with an emphasis on the latter two. Key material to be presented includes 1) voltammetric data for the solutions, 2) x-ray diffractometry data for deposited films, 3) a discussion of the numerous practical problems associated withhigh temperature electrochemistry, especially incorrosive, volatile systems, and 4) emphasis of the value of an operationally feasible high temperature plating system to the commercial viabilityof electrodeposited semiconductor films

Diagnostics of CdTe Electrodeposition by Rest Potential Voltammetry

Due to the extreme sensitivity of the partial elemental currents (i.e.,iCd, iTe) and, hence, stoichiometry to deposition voltage, temperature, mass transport, and ambient light intensity during electrodeposition of semiconductor films, it is important to implement in-situ methods for monitoring the stoichiometry and related semiconductor efficacy of the growing film. We report investigation of open circuit rest potential (Eoc) voltammetry as one such method during electrodeposition of CdTe from aprotic electrolytes such as ethylene glycol. Plots of transient open circuit potential versus sweep voltage exhibit distinct transition and plateau structures corresponding to Te, CdTe, and Cd phases and correlating with the appearance/disappearance of photocurrent, x-ray diffraction evidence of the three phases, and optical obsorption spectroscopy. In particular, the Eoc plateau corresponding to deposition of near-stoichiometric CdTe can be used to monitor and control the deposition process

The effects of environmental temperature and alerting stimuli on prolonged search.

PsychologyDoctor of Philosophy (PhD

Conformational Propensities of a DNA Hairpin with a Stem Sequence from the c-MYC Promoter

G-quadruplexes and i-motifs are four-stranded non-canonical structures of DNA. They exist in the cell, where they are implicated in the conformational regulation of cellular events, such as transcription, translation, DNA replication, telomere homeostasis, and genomic instability. Formation of the G-quadruplex and i-motif conformations in the genome is controlled by their competition with the pre-existing duplex. The fate of that competition depends upon the relative stabilities of the competing conformations, leading ultimately to a distribution of double helical, tetrahelical, and coiled conformations that coexist in dynamic equilibrium with each other. We previously developed a CD spectroscopy-based procedure to characterize the distribution of conformations adopted by equimolar mixtures of complementary G- and C-rich DNA strands from the promoter regions of the c-MYC, VEGF, and Bcl-2 oncogenes. In those bimolecular systems, duplex-to-tetraplex and duplex-to-coil transitions are accompanied by strand separation and an associated entropic cost. This situation is distinct from the pseudo-monomolecular nature of conformational transformations within the genome, where strand separation does not occur. To mimic better the situation in the genome, we here extend our studies to a monomolecular DNA construct—a hairpin—in which complementary G- and C-rich strands featuring sequences from the promoter region of the c-MYC oncogene are linked by a dT11 loop. We used our CD-based procedure to quantify the distribution of conformational states sampled by the hairpin at pH 5.0 and 7.0 as a function of temperature and the concentration of KCl. The data were analyzed according to a thermodynamic model based on equilibria between the different conformational states to evaluate the thermodynamic properties of the duplex-to-coil, G-quadruplex-to-coil, and i-motif-to-coil transitions of the hairpin. The results have implications for the modulation of such transitions as a means of therapeutic intervention

Thermodynamic Characterization of Non-Canonical DNA Structures

In this work, we discussed the importance of heat capacity in evaluation of thermodynamic parameters such as ΔG, ΔH and ΔS. We used DSC to measure directly changes in heat capacity accompanying unfolding of DNA from the promoters of the c-MYC, VEGF and Bcl-2 oncogenes. The most accurate means of determining heat capacity changes accompanying GQ unfolding is provided by DSC measurements. Although DSC has been used to determine changes in heat capacity accompanying duplex-to-single strand transitions, there has been a lack of similar studies of GQ. This study provided conclusive evidence of the existence of ΔCP in GQ unfolding. To further reiterate the dramatic effect that ΔCP has on thermodynamic parameters, the extrapolated values of ΔG, ΔH and ΔS were compared for ΔCP = 0 and ΔCP ≠ 0. When extrapolated to biologically relevant temperatures, the value of ΔG, when ΔCP is neglected, the error margin may be as large as 140%. Moreover, we designed a hairpin-based monomolecular DNA construct to further understand duplex-tetraplex equilibria. The sequence of the hairpin is derived from the c-MYC oncogene with the G-rich and C-rich strands by a T11 link. We used a CD-based approach to characterize the distribution of conformational states as a function of environmental conditions. Our work further reiterated the notion that both GQs and iM can exist in tandem.M.Sc

The Social Impact of Artificial Intelligence

Artificial intelligence (AI) has become important in modern life. The authors study in this article about the social impact of AI; they also highlight its social importance, as it facilitates community services and satisfies the requirements of societal sectors. Among the prominent advantages of using AI in society are facilitating individual services such as customer service centers, gaining customer satisfaction, and facilitating electronic dealings. Its disadvantages are the unemployment problem such as replacing employees by robots, limited options in the labor market, negative impacts on the youth especially teenagers, and the inability of robots in dealing with the elders for giving them the sympathy and social support. AI also faces many challenges such as concerns about disinformation by fake news, secret surveillance, and lack of solutions for laid-off employees because AI systems have replaced them, which may lead to limited jobs in the future.</jats:p

FORMULATION DEVELOPMENT OF ORAL FAST-DISSOLVING FILMS OF RUPATADINE FUMARATE

Objective: Rupatadine fumarate (RF) is an anti-allergic drug indicated for the treatment of allergic rhinitis. It has low oral bioavailability due to its poor aqueous solubility and extensive hepatic first pass metabolism. In the present work, oral fast-dissolving films (OFDF) have been formulated and evaluated to facilitate dissolution in the oral cavity itself. Methods: Pullulan and HPMC (5, 15 cps) were employed as film formers and six formulations were tried. The physicochemical compatibility between drug and the polymers was studied by FTIR spectroscopy. RF-beta-cyclodextrin (BCD) inclusion complex was initially prepared and evaluated. The inclusion complex was incorporated into the film. OFDF were formulated and prepared by solvent casting method. The film size for one dose was 2 × 2 cm. The films were evaluated for various film parameters including disintegration time and drug release. Results: Preliminary film studies indicated % of film former solution to be between 3 and 5% for good appearance, mechanical strength, and quick disintegration. Solubility enhancement of RF is almost 40-fold from its BCD inclusion complex. Drug content in the films ranged between 83 and 90%. The pH ranged between 6 and 7 for all the formulations. All OFDF of RF disintegrated within one minute. With higher viscosity grade of HPMC, disintegration was comparatively slower and so was the drug release. Pullulan based films also showed desirable properties. F3 had disintegration time was 28 s and % drug release was 92% in 180 s. Conclusion: OFDF of RF could be formulated employing pullulan and HPMC low viscosity grades by solvent casting method. F3 containing HPMC E5 at 37% by weight of dry film showed desirable film properties. Stability studies indicated that there was no significant change in the films with respect to physicochemical properties and in vitro release