Studies of the Structural Boundaries of Solid-State Photodimerization Reactions via Isocoumarins and Heteromeric Assemblies

The study of molecules in crystals has gained considerable attention in the field of structural chemistry. Much interest has focused on the use of molecular crystals for the construction of materials with specific functional properties. Because the design of such materials requires a critical understanding of intermolecular interactions, use of the building-block approach continues to offer an important strategy to multimolecular frameworks. Though the use of template and metal-ligand interactions has provided successful opportunities to organize chemical reactions in solids, these methods require secondary molecules and are limited to achiral starting materials. As such, exploring chiral synthesis with simplified precursors holds much promise to the design of next generation materials. Recent research conducted in Dr. Wheeler\u27s group focused on [2+2] photodimerization reactions of olefins by investigating a family of cinnamylsulfonamides that self-assemble to give photoreactive dimers. Though photodimerization in solids has been extensively studied, photobehavior of cocrystalline systems constructed from two chemically distinct molecules and chiral materials are rare. This thesis focuses on a cocrystalline approach for the construction of multicomponent assemblies to study solid-state [2+2] photodimerization reactions. Racemic alanine sulfonamidecinnamic acid (a fish hook shaped molecule) successfully cocrystallized with co-formers 4,4\u27-dipyridyl, 4,4\u27-dipyridyl-N,N\u27-dioxide dehydrate, and trans-1,2-bis(4-pyridyl)ethylene by use of the complementary features of hydrogen bonds and molecular shape to form supramolecular tetramers. The co-former (E)-but-2-enediamide did not result in cocrystal formation. Though cocrystals obtained from co-former trans-1,2-bis(4-pyridyl)ethylene effectively organized adjacent olefins for [2+2] photodimerization reaction via an inter-dimer route, UV illumination did not result in the cyclobutane photoproduct. In a second study, racemic and chiral syntheses of sulfonamide isocoumarin compounds and their [2+2] photodimerization reactions were examined. Two fish-hook shape molecules were synthesized by use of racemic and homochiral sulfonamide isocoumarin compounds. All synthetic steps were analyzed using NMR techniques, and where possible, X-ray crystallography. Racemic isocoumarin was crystallized by use of hydrogen bonds to form a supramolecular homodimer. These homodimers aligned with favorable olefin· · · olefin spacing for UV initiated single-crystal-to-single-crystal (SCSC) [2+2] photodimerization reactions to give cyclobutane photoproduct in 100% conversion. While homochiral isocoumarin could not be processed as a SCSC reaction, photoirradiation of a powdered sample gave cyclobutane photoproduct in 64.6% conversion as revealed by NMR studies

Spectral signatures of thermal spin disorder and excess Mn in half-metallic NiMnSb

Effects of thermal spin disorder and excess Mn on the electronic spectrum of half-metallic NiMnSb are studied using first-principles calculations. Temperature-dependent spin disorder, introduced within the vector disordered local moment model, causes the valence band at the $\Gamma$ point to broaden and shift upwards, crossing the Fermi level and thereby closing the half-metallic gap above room temperature. The spectroscopic signatures of excess Mn on the Ni, Sb, and empty sites (Mn$_\mathrm{Ni}$, Mn$_\mathrm{Sb}$, and Mn$_\mathrm{E}$) are analyzed. Mn$_\mathrm{Ni}$ is spectroscopically invisible. The relatively weak coupling of Mn$_\mathrm{Sb}$ and Mn$_\mathrm{E}$ spins to the host strongly deviates from the Heisenberg model, and the spin of Mn$_\mathrm{E}$ is canted in the ground state. While the half-metallic gap is preserved in the collinear ground state of Mn$_\mathrm{Sb}$, thermal spin disorder of the weakly coupled Mn$_\mathrm{Sb}$ spins destroys it at low temperatures. This property of Mn$_\mathrm{Sb}$ may be the source of the observed low-temperature transport anomalies.Comment: 5 pages, 7 figures, updated version with minor revisions and an additional figure, accepted in Phys. Rev. B (Rapid Communication

Pressure Thresholds and Stiffness on the Plantar Surface of the Human Foot

The objective was to develop a methodology to assess Pressure Discomfort Thresholds (PDT), Pressure Pain Thresholds (PPT), and tissue stiffness on the plantar surface of the foot. Ten male and ten female participants volunteered for the study. Foot landmarks were used to create a standardized grid-type template of 95 points. For each test point, PPT and PDT values were obtained, and stiffness was calculated for each of the twenty participants. Cluster analyses were performed to determine the regions of similarity for the three dependent variables, PPT, PDT and stiffness. Moran’s-I-index was used to determine the spatial auto correlations. The use of k-means clustering showed five distinct clusters while the three dependent variables showed strong correlations to each other. Morisita’s similarity index was used to check the similarity of the grid among all participants. Both male and female participants showed a Morisita’s index greater than 0.7 confirming the reliability of the foot template

Prevalence of frailty and prefrailty among community-dwelling older adults in low-income and middle-income countries: a systematic review and meta-analysis

OBJECTIVE: To systematically review the research conducted on prevalence of frailty and prefrailty among community-dwelling older adults in low-income and middle-income countries (LMICs) and to estimate the pooled prevalence of frailty and prefrailty in community-dwelling older adults in LMICs. DESIGN: Systematic review and meta-analysis. PROSPERO registration number is CRD42016036083. DATA SOURCES: MEDLINE, EMBASE, AMED, Web of Science, CINAHL and WHO Global Health Library were searched from their inception to 12 September 2017. SETTING: Low-income and middle-income countries. PARTICIPANTS: Community-dwelling older adults aged ≥60 years. RESULTS: We screened 7057 citations and 56 studies were included. Forty-seven and 42 studies were included in the frailty and prefrailty meta-analysis, respectively. The majority of studies were from upper middle-income countries. One study was available from low-income countries. The prevalence of frailty varied from 3.9% (China) to 51.4% (Cuba) and prevalence of prefrailty ranged from 13.4% (Tanzania) to 71.6% (Brazil). The pooled prevalence of frailty was 17.4% (95% CI 14.4% to 20.7%, I²=99.2%) and prefrailty was 49.3% (95% CI 46.4% to 52.2%, I²=97.5%). The wide variation in prevalence rates across studies was largely explained by differences in frailty assessment method and the geographic region. These findings are for the studies with a minimum recruitment age 60, 65 and 70 years. CONCLUSION: The prevalence of frailty and prefrailty appears higher in community-dwelling older adults in upper middle-income countries compared with high-income countries, which has important implications for healthcare planning. There is limited evidence on frailty prevalence in lower middle-income and low-income countries

The Psychological Impact of Austerity: A Briefing Paper

This report directly links cuts to public services with mental health problems. Well-established psychological research that explains these links already exists. However, this knowledge has been missing from the debate on austerity so far. Psychologists are often in a position to see the effects that social and economic changes have on people. We also occupy a relatively powerful position as professionals and therefore have an ethical responsibility to speak out about these effects. Key conclusions: Austerity policies have damaging psychological costs. Mental health problems are being created in the present, and further problems are being stored for the future. We have identified five ‘Austerity Ailments’. These are specific ways in which austerity policies impact on mental health: 1. Humiliation and shame 2. Fear and distrust 3. Instability and insecurity 4. Isolation and loneliness 5. Being trapped and powerless These experiences have been shown to increase mental health problems. Prolonged humiliation following a severe loss trebles the chance of being diagnosed with clinical depression. Job insecurity is as damaging for mental health as unemployment. Feeling trapped over the long term nearly trebles the chances of being diagnosed with anxiety and depression. Low levels of trust increase the chance of being diagnosed with depression by nearly 50 per cent. These five ‘ailments’ are indicators of problems in society, of poisonous public policy, weakness of social cohesion and inequalities in power and wealth. We also know what kind of society promotes good health. Key markers are that societies are equal, participatory and cohesive. Some important indicators of a psychologically healthy society are: 1. Agency 2. Security 3. Connection 4. Meaning 5. Trust Mental health isn’t just an individual issue. To create resilience and promote wellbeing, we need to look at the entirety of the social and economic conditions in which people live

Association between frailty and disability among rural community-dwelling older adults in Sri Lanka: a cross-sectional study

OBJECTIVE: We examined the association between frailty and disability in rural community-dwelling older adults in Kegalle district of Sri Lanka. DESIGN: A population-based cross-sectional study. PARTICIPANTS: A total of 746 community-dwelling adults aged ≥60 years. PRIMARY AND SECONDARY OUTCOME MEASURES: Frailty was assessed using the Fried phenotype. Disability was operationalised in terms of having one or more activity limitation/s in instrumental activities of daily living (IADL) and basic activities of daily living (BADL). RESULTS: The median age of the sample was (median 68; IQR 64-75) years and 56.7% were female. 15.2% were frail and 48.5% were prefrail. The prevalence of ≥1 IADL limitations was high, 84.4% among frail adults. 38.7% of frail adults reported ≥1 BADL limitations. Over half of frail older adults (58.3%) reported both ≥1 physical and cognitive IADL limitations. Being frail decreased the odds of having no IADL limitations, and was associated with a higher count of IADL limitations. No significant association was found between prefrailty and number of IADL limitations. CONCLUSIONS: The prevalence of ≥1 IADL limitations was high among rural community-dwelling frail older adults. Findings imply the greater support and care required for rural Sri Lankan frail older adults to live independently in the community

An Overlapping Case of Lupus Nephritis and IgG4-Related Kidney Disease

We report a case of a 71-year-old Filipino female who was admitted to the hospital for abdominal pain, vomiting and diarrhea of 8 days duration. The patient was found to have marked acute kidney injury (AKI), which required hemodialysis in the next 3 days. Extensive workup revealed hematuria, subnephrotic range proteinuria, elevated anti-nuclear antibody (ANA) and elevated total immunoglobulin G (IgG) levels, with normal IgG4 and anti-dsDNA levels. On kidney biopsy, mild membranous glomerulonephritis was found, along with autoimmune tubulointerstitial nephritis (TIN) with a full-house pattern of immune deposits. These findings were suggestive of lupus interstitial nephritis. However, IgG4+ plasma cells were detected in the interstitium by immunostaining, favoring a diagnosis of IgG4-related kidney disease (IgG4-RKD). Our case highlights the difficulty in differentiating lupus nephritis (LN) from IgG4-RKD in some patients, raising the suspicion that these two entities can co-exist