404 research outputs found

    Identifying the Optimal Age to Perform Newborn Screening for Hearing Loss in Uganda

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    Background: Permanent congenital hearing loss affects up to 6/1000 births in developing countries. Currently, in Uganda there is no newborn screening for hearing loss (NSHL) program and no published work on this topic. Within the existing healthcare system there are two opportunities to deliver screening, at birth or 6 weeks of age when infants receive their immunizations. Aim: This study explored the outcomes of otoacoustic emission (OAE) testing in infants at birth and 6 weeks of age, to identify the optimal age for screening. Subjects and Methods: This cross‑sectional pilot study recruited 60 consecutive infants from two health centres in Kampala, Uganda. Thirty infants were newborns recruited from the postnatal ward and 30 were aged 4–8 weeks from the immunization clinic, we performed OAE testing on all infants. Results: The results showed 56.7% (17/30) of newborn infants passed OAE testing compared with 90.0% (27/30) of the immunization infants, P < 0.01. Furthermore, of the 11 newborn infants aged ≄24 h of age 90.9% (10/11) passed, compared with the 19 infants <24 h of age where 37% (7/19) passed, P < 0.01. Conclusions: This study demonstrates a higher pass rate for OAE testing for infants ≄24 h of age compared to those <24 h of age. The overall lower pass rate of the newborn infants could be due to external ear debris and middle ear fluid compromising the OAE testing. These findings would support a NSHL programme in Uganda that offers screening to infants ≄24 h of age, to maximize the cost‑effectiveness of the program.Keywords: Hearing loss, Newborn, Screenin

    Synthesis and conformational studies of chiral macrocyclic [1.1.1]metacyclophanes containing benzofuran rings

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    Macrocyclic [1.1.1]metacyclophanes (MCPs) containing benzene and benzofuran rings linked by methylene bridges and which can be viewed as calixarene analogues, have been synthesized by demethylation of [3.3.1]MCP-diones with trimethylsilyl iodide (TMSI) in MeCN. The [3.3.1]MCP-diones are synthesized by using (p-tolylsulfonyl)methyl isocyanide (TosMIC) as the cyclization reagent in N,N-dimethylformamide (DMF) with an excess of sodium hydride. ÂčH NMR spectroscopy revealed that the remaining hydroxyl group on the phenyl ring is involved in intramolecular hydrogen bonding with the oxygen of one of the benzofuran rings. O-Methylation at the lower rim of monohydroxy[1.1.1]MCP in the presence of K₂CO₃ in acetone afforded a novel and inherently chiral calixarene analogue, namely the macrocyclic [1.1.1]MCP, possessing C₁ symmetry. The inherent chirality of the two conformers was characterized by ÂčH NMR spectroscopy by addition of an excess of Pirkle's chiral shift reagent, which caused a splitting of the corresponding methylene protons to AB patterns. Single crystal X-ray analysis revealed the adoptation of a hemisphere-shaped cone isomer. DFT calculations were carried out to investigate the energy-minimized structures and the hydrogen bonds of the synthesized MCPs

    Synthesis and conformations of [2.n]metacyclophan-1-ene epoxides and their conversion to [n.1]metacyclophanes

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    A series of syn- and anti-[2.n]metacyclophan-1-enes have been prepared in good yields by McMurry cyclizations of 1,n-bis(5-tert-butyl-3-formyl-2-methoxyphenyl)alkanes. Significantly, acid catalyzed rearrangements of [2.n]metacyclophan-1-enes afforded [n.1]metacyclophanes in good yield. The ratios of the products are strongly regulated by the number of methylene bridges present. The percentages of the rearrangement products increase with increasing length of the carbon bridges. Characterization and the conformational studies of these products are described. Single crystal X-ray analysis revealed the adoption of syn- and anti-conformations. DFT calculations were carried out to estimate the energy-minimized structures of the synthesized metacyclophanes

    Synthesis, structures and conformational studies of 1,2-dimethyl[2.10]metacyclophane-1-enes

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    A series of 1,2-dimethyl[2.10]metacyclophan-1-enes (MCP-1-enes) containing different substituent groups has been synthesized to illustrate their conformational behavior. 4,22-dimethoxy-1,2-dimethyl[2.10]MCP-1-ene 3 was synthesized by a Grignard coupling reaction, Friedel-Crafts acylation reactions and McMurry coupling reaction from 1,10-dibromodecane. The formation of 4,22-dihydroxy-1,2-dimethyl[2.10]MCP-1-ene 4 was carried out by demethylation of compound 3 with boron tribromide at room temperature. The syn type conformation of 4 was characterized by X-ray diffraction and was found to form both intramolecular and intermolecular hydrogen bonds between the two hydroxyl groups. From this reaction an interesting compound [10]tetrahydrobenzofuranophane 5 was afforded on prolonging the reaction time. 5,21-diformyl-4,22-dihydroxy-1,2-dimethyl[2.10]MCP-1-ene 6 has been prepared from 4,22-dihydroxy-1,2-dimethyl[2.10]MCP-1-ene 4 by using the Duff method in the presence of hexamethylenetetramine. Structural analysis by 1H NMR spectroscopy and X-ray diffraction confirmed that both the solution and the crystalline state of compound 6 adopts an anti-conformation which forms an intramolecular hydrogen bond between the formyl group and the hydroxyl group, which is an interesting finding for long carbon chain MCP compounds

    Fluorescent turn-on sensors based on pyrene-containing Schiff base derivatives for Cu2+ recognition: spectroscopic and DFT computational studies

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    A new fluorescent chemosensor L1, pyrene containing long chain Schiff base derivative in 1-position has been synthesized. Similarly, the receptors L2 and L3 are also designed in order to compare the binding ability for detection of Cu2+. The receptors exhibit very weak fluorescence (Ί = 0.01) due to the photoinduced electron transfer (PET). Upon addition of 10 equiv. of Cu2+, the emission intensity of ligands L1 and L2 are increased 65-fold (Ί = 0.31) and 25-fold (Ί = 0.08) in CH3CN/CH2Cl2 solvents system respectively. NMR titration experiments, spectroscopic and DFT computational studies confirmed the binding phenomena and sensitivity of Cu2+

    Systematic review of qualitative evaluations of reentry programs addressing problematic drug use and mental health disorders amongst people transitioning from prison to communities

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    © 2018, The Author(s). Background: The paper presents a systematic review and metasynthesis of findings from qualitative evaluations of community reentry programs. The programs sought to engage recently released adult prison inmates with either problematic drug use or a mental health disorder. Methods: Seven biomedical and social science databases, Cinahl, Pubmed, Scopus, Proquest, Medline, Sociological abstracts and Web of Science and publisher database Taylor and Francis were searched in 2016 resulting in 2373 potential papers. Abstract reviews left 140 papers of which 8 were included after detailed review. Major themes and subthemes were identified through grounded theory inductive analysis of results from the eight papers. Of the final eight papers the majority (6) were from the United States. In total, the papers covered 405 interviews and included 121 (30%) females and 284 (70%) males. Results: Findings suggest that the interpersonal skills of case workers; access to social support and housing; and continuity of case worker relationships throughout the pre-release and post-release period are key social and structural factors in program success. Conclusion: Evaluation of community reentry programs requires qualitative data to contextualize statistical findings and identify social and structural factors that impact on reducing incarceration and improving participant health. These aspects of program efficacy have implications for reentry program development and staff training and broader social and health policy and services

    Synthesis and evaluation of a novel ionophore based on a thiacalix[4]arene derivative bearing imidazole units

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    O-Alkylation of the flexible thiacalix[4]arene 1 with 2-chloromethyl-1-methyl-1H-imidazole 2 in the presence of Na₂CO₃ or K₂CO₃ afforded mono-O-alkylation product 3 in 29–51% yield, along with recovery of the starting compound. In contrast, the same reaction in the presence of Cs₂CO₃ gave only one pure stereoisomer, namely 1,3-alternate-4; other possible isomers were not observed. Alkali metal salts such as Na₂CO₃ and Cs₂CO₃ can play an important role in the conformer distribution via a template effect. The conformations of the receptors, mono-O-alkylation product 3 and that of 1,3-alternate-4, have been confirmed by X-ray crystallography. Furthermore, the complexation properties of the receptor 1,3-alternate-4 toward selected alkali/transition metal cations are reported. The two-phase solvent extraction data indicated that 1,3-alternate-4 exhibited a stronger extraction efficiency for transition metals over alkali metals. The dichromate anion extraction ability of 1,3-alternate-4 showed that it could serve as an efficient extractor of HCr₂O₇⁻/Cr₂O₇ÂČ⁻ anions at low pH

    Selective ethylene trimerization by titanium complexes bearing phenoxy-imine ligands: NMR and EPR Spectroscopic studies of the reaction intermediates

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    The catalyst systems (FI)TiCl₃/MAO (FI = phenoxyimine ligand with an additional aryl–O–CH₃ donor) display exceptionally high activity in selective ethylene trimerization. By means of NMR and EPR spectroscopy, the nature of the Ti species formed in the catalyst systems (FI)TiCl₃/MAO, (FI)TiCl₃/MMAO, and (FI)TiCl₃/AlR₃/[Ph₃C]âș[B(C₆F₅)₄]⁻ (R = Me, Et, ⁱBu) has been studied. It was shown that outer-sphere ion pairs of the type [(FI)TiIVMe₂]âș[A]⁻ ([A]− = [MeMAO]⁻, [MeMMAO]⁻, [B(C₆F₅)₄]⁻) are formed at the initial stage of the reaction of (FI)TiCl₃ with MAO, MMAO, and AlMe₃/[Ph₃C]âș[B(C₆F₅)₄]⁻. These ion pairs further partially convert into TiIII and TiII species. In the systems (FI)TiCl₃/MAO and (FI)TiCl₃/AlMe₃/[Ph₃C]âș[B(C₆F5)₄]⁻, complexes with the proposed structures (FI)TiIIIMe₂, (FI)TiIICl, and [(FI)TiII(S)]âș[A]⁻ ([A]− = [MeMAO]⁻, [B(C₆F₅)4)]⁻, S = solvent, vacancy) were observed (concentrations of TiIII species was lower than those of the TiII congeners). In contrast, in the system (FI)TiCl₃/MMAO, the concentrations of TiIII species (ion pairs of the type [(FI)TiIII(ÎŒ-H)(ÎŒ-Cl)AlⁱBu₂]âș[MeMMAO]⁻) were higher than those of the TiII counterparts (ion pairs [(FI)TiII(S)]âș[MeMMAO]⁻). The system (FI)TiCl₃/MMAO displays lower activity and selectivity in 1-hexene formation, in comparison to (FI)TiCl₃/MAO, due to undesirable PE generation. Probably, TiII and TiIV ion pairs are those participating in ethylene trimerization

    QED calculation of the n=1 and n=2 energy levels in He-like ions

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    We perform ab initio QED calculations of energy levels for the n=1n=1 and n=2n=2 states of He-like ions with the nuclear charge in the range Z=12Z = 12-100. The complete set of two-electron QED corrections is evaluated to all orders in the parameter \aZ. Uncalculated contributions to energy levels come through orders \alpha^3 (\aZ)^2, \alpha^2 (\aZ)^7, and higher. The calculation presented is the first treatment for excited states of He-like ions complete through order \alpha^2 (\aZ)^4. A significant improvement in accuracy of theoretical predictions is achieved, especially in the high-ZZ region.Comment: 23 pages, 5 figure
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