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The efficient delivery of reactive and toxic gaseous reagents to organic reactions was studied using metal-organic frameworks (MOFs). The simultaneous cargo vehicle and catalytic capabilities of several MOFs were probed for the first time using the examples of aromatization, aminocarbonylation, and carbonylative Suzuki-Miyaura coupling reactions. These reactions highlight that MOFs can serve a dual role as a gas cargo vehicle and a catalyst, leading to product formation with yields similar to reactions employing pure gases. Furthermore, the MOFs can be recycled without sacrificing product yield, while simultaneously maintaining crystallinity. The reported findings were supported crystallographically and spectroscopically (e.g., diffuse reflectance infrared Fourier transform spectroscopy), foreshadowing a pathway for the development of multifunctional MOF-based reagent-catalyst cargo vessels for reactive gas reagents as an attractive alternative to the use of toxic pure gases or gas generators.
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The synthesis of well-defined heterometallic complexes remains a frontier challenge in inorganic chemistry. We report an approach that relies on the sequential insertion of electrophilic metal fragments into electron-rich Ru-B bonds of the η2-BB-carboryne complex (POBBOP)Ru(CO)2 [POBBOP = 1,7-OP(iPr)2-m-2,6-dehydrocarborane]. Utilizing this synthetic strategy, bimetallic (POBBOP)(Ru)(CO)2[Pd(PtBu3)] and trimetallic (POBBOP)(Ru)(CO)2[Pd(PtBu3)](CuBr) complexes were selectively prepared. Structural and theoretical analysis of the features of chemical bonding within Ru-B-B-Cu and Ru-B-B-Pd fragments is presented.
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Inter-population disparities in a species have been shown to occur as an adaptation to different thermal regimes in the environment. We investigated the thermal sensitivities of the tropical toad Duttaphrynus melanostictus (Asia Common Toad) from two populations at different altitudes: Nuwara-Eliya - 1870 m, and Polonnaruwa - 25 m, above mean sea level. The two locations were separated by what may be considered a short direct distance - 110 km. Thermal sensitivity trials were conducted at six temperatures between 12 and 39 °C. Assessments were made using the performance indicators jump distance, jump force, contact time on the test plate following stimulus to jump, and righting time after being overturned. Optimum performance is taken to be the greatest jump distance and jump force, the least contact time on the test plate, and the least righting time. The populations at the two altitudes had markedly different thermal sensitivities - toads in the cool area (Nuwara-Eliya) performed at an optimal level under low temperatures, whereas the toads in the warm area (Polonnaruwa) performed optimally under high temperatures. The finding that the thermal optima (i.e., the temperatures at which the optimal performance for the four performance indicators was recorded) of the toads in Polonnaruwa were below the mean maximum ambient temperature at this location suggests that these toads would be more susceptible to global warming than those in Nuwara-Eliya whose thermal optima were above the mean maximum ambient temperature in that location. This was consistent with the narrower thermal safety margin (i.e., difference between the mean optimum temperature and mean ambient temperature) of toads in Polonnaruwa, compared to those in Nuwara-Eliya. Importantly, these findings demonstrate that, although thermal sensitivity is considered a conservative trait, differentiation does occur even over a small spatial scale presumably because it offers an adaptive advantage to the population concerned.
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Variação Biológica da População , Bufonidae/fisiologia , Termotolerância , Animais , Bufonidae/genética , Ecossistema , Movimento , Sri LankaRESUMO
OBJECTIVES: Over a quarter of UK births are to women who were born outside of the UK. Black and Minority Ethnic (BME) women are disproportionately affected by poor mental health and inequitable access to mental health care in the perinatal period, yet the influence of the migrant status (mothers' UK vs. non-UK birth) is poorly understood. This study aimed to explore the relationship between ethnicity, migration and mental health indicators among mothers participating in a large nationally representative cohort study. STUDY DESIGN: This is a secondary analysis of data from the Millennium Cohort Study. METHODS: Logistic regression quantified the crude and adjusted effects of self-reported ethnicity and migrant status on prevalence of psychological distress and treatment for anxiety/depression at 9-month and 5-year postpartum. RESULTS: We found substantial variation in the prevalence of distress according to ethnicity and migrant status, with Indian and Pakistani women at greatest risk. Despite equal or greater risk, BME and migrant women were less likely to report treatment for anxiety/depression. Mutually adjusted analyses showed ethnicity to be a stronger predictor of both outcomes than migrant status; however, at 5 years, being a migrant independently predicted lower odds of treatment, for a statistically similar level of distress. CONCLUSIONS: Migrant women are likely to be at high risk of poor mental health in the perinatal period and beyond, yet may face significant barriers to accessing mental health care. A better understanding of ethnicity and migration as interrelated risk factors for perinatal mental ill-health is needed to help National Health Service organisations develop policy and practice that is flexible and responsive to diversity.
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População Negra/psicologia , Etnicidade/psicologia , Transtornos Mentais/epidemiologia , Transtornos Mentais/terapia , Grupos Minoritários/psicologia , Mães/psicologia , Migrantes/psicologia , Adulto , Ansiedade/epidemiologia , Ansiedade/etnologia , Ansiedade/terapia , População Negra/estatística & dados numéricos , Estudos de Coortes , Depressão/epidemiologia , Depressão/etnologia , Depressão/terapia , Etnicidade/estatística & dados numéricos , Feminino , Acessibilidade aos Serviços de Saúde , Humanos , Transtornos Mentais/etnologia , Serviços de Saúde Mental , Grupos Minoritários/estatística & dados numéricos , Mães/estatística & dados numéricos , Período Pós-Parto , Gravidez , Prevalência , Fatores de Risco , Autorrelato , Migrantes/estatística & dados numéricos , Reino Unido/epidemiologiaRESUMO
BACKGROUND: Learning and memory impairments in older adults with depression are linked to hippocampal atrophy. However, other subcortical regions may also be contributing to these deficits. We aimed to examine whether anterior caudate nucleus volume is significantly reduced in older adults with depression compared to controls; whether anterior caudate volume is associated with performance on tasks of episodic learning and memory, and if so, whether this association is independent of the effects of the hippocampus. METHOD: Eighty-four health-seeking participants meeting criteria for lifetime major depressive disorder (mean age = 64.2, s.d. = 9.1 years) and 27 never-depressed control participants (mean age = 63.9, s.d. = 8.0 years) underwent neuropsychological assessment including verbal episodic memory tests [Rey Auditory Verbal Learning Test and Logical Memory (WMS-III)]. Magnetic resonance imaging was conducted, from which subregions of the caudate nucleus were manually demarcated bilaterally and hippocampal volume was calculated using semi-automated methods. RESULTS: Depressed subjects had smaller right anterior caudate (RAC) (t = 2.3, p = 0.026) and poorer memory compared to controls (t = 2.5, p < 0.001). For depressed subjects only, smaller RAC was associated with poorer verbal memory (r = 0.3, p = 0.003) and older age (r = -0.46, p < 0.001). Multivariable regression showed that the RAC and hippocampus volume uniquely accounted for 5% and 3% of the variance in memory, respectively (ß = 0.25, t = 2.16, p = 0.033; ß = 0.19, t = 1.71, p = 0.091). CONCLUSIONS: In older people with depression, the anterior caudate nucleus and the hippocampus play independent roles in mediating memory. While future studies examining this structure should include larger sample sizes and adjust for multiple comparisons, these findings support the critical role of the striatum in depression.
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Núcleo Caudado/patologia , Transtorno Depressivo Maior/patologia , Transtorno Depressivo Maior/fisiopatologia , Hipocampo/patologia , Transtornos da Memória/patologia , Transtornos da Memória/fisiopatologia , Memória Episódica , Aprendizagem Verbal/fisiologia , Idoso , Núcleo Caudado/diagnóstico por imagem , Transtorno Depressivo Maior/complicações , Transtorno Depressivo Maior/diagnóstico por imagem , Feminino , Hipocampo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino , Transtornos da Memória/diagnóstico por imagem , Transtornos da Memória/etiologia , Pessoa de Meia-IdadeRESUMO
Coupling of octahedral, terminal d1 molybdenum(v) nitrido complexes supported by a dianionic pentadentate ligand via N-N bond formation to give µ-dinitrogen complexes was found to be thermodynamically feasible but faces significant kinetic barriers. However, upon oxidation, a kinetically favored nucleophilic/electrophilic N-N bond forming mechanism was enabled to give monocationic µ-dinitrogen dimers. Computational and experimental evidence for this "oxidation-induced ambiphilic nitrido coupling" mechanism is presented. The factors influencing release of dinitrogen from the resulting µ-dinitrogen dimers were also probed and it was found that further oxidation to a dicationic species is required to induce (very rapid) loss of dinitrogen. The mechanistic path discovered for N-N bond formation and dinitrogen release follows an ECECC sequence (E = "electrochemical step"; C = "chemical step"). Experimental evidence for the intermediacy of a highly electrophilic, cationic d0 molybdenum(vi) nitrido in the N-N bond forming mechanism via trapping with an isonitrile reagent is also discussed. Together these results are relevant to the development of molecular catalysts capable of mediating ammonia oxidation to dihydrogen and dinitrogen.
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AIMS: Fulvestrant is a selective oestrogen receptor (ER) degrader used in postmenopausal women with hormone receptor-positive advanced breast cancer. The study aim was to analyse demographics and outcomes of UK patients treated with fulvestrant monotherapy at nine representative centres. MATERIALS AND METHODS: Medical records of 459 patients with locally advanced or metastatic ER-positive, HER2-negative breast cancer treated with fulvestrant between August 2011 and November 2018 at nine UK centres were reviewed. Data were collated on demographics, progression-free survival, overall survival and disease response at first radiological assessment following fulvestrant initiation. Patients still alive by December 2018 were censored. RESULTS: Data from 429 of the 459 patients identified were eligible for inclusion in the analysis. The median age was 69 (range 21-95) and 64% (n = 275) had Eastern Cooperative Oncology Group performance status 0-1. Bone was the most commonly involved metastatic site (72%, n = 306). However, 295 (69%) patients had visceral involvement. Patients had received a median 2 (range 0-5) prior lines of endocrine therapy and median 0 (range 0-6) prior chemotherapies. Fulvestrant was first-line therapy in 43 patients (10%). The median duration of treatment was 5 months (range 1-88). The median progression-free survival was 5.5 months. In 51% of 350 patients radiologically assessed, there was evidence of disease response to fulvestrant. Fifteen per cent of these had a complete/partial response. Fulvestrant was discontinued predominantly due to disease progression, with 3% discontinued solely due to adverse events. The median overall survival for the whole cohort was 22.5 months (range 0-88). CONCLUSIONS: This is one of the largest studied cohorts of breast cancer patients treated with fulvestrant. This heavily endocrine-pretreated population reflects real-life use in the UK. Within this context, our retrospective data show that patients can experience maintained disease response when treated with fulvestrant, supporting the importance of equitable availability for all UK patients.
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Neoplasias da Mama , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/patologia , Estradiol/uso terapêutico , Feminino , Fulvestranto/efeitos adversos , Humanos , Receptor ErbB-2 , Receptores de Estrogênio/uso terapêutico , Receptores de Progesterona/uso terapêutico , Estudos RetrospectivosRESUMO
Carbon atom functionalization via generation of carbanions is the cornerstone of carborane chemistry. In this work, we report the synthesis and structural characterization of free ortho-carboranyl [C2B10H11]-, a three-dimensional inorganic analog of the elusive phenyl anion that features a "naked" carbanion center. The first example of a stable, discrete C(H)-deprotonated carborane anion was isolated as a completely separated ion pair with a crown ether-encapsulated potassium cation. An analogous approach led to the isolation and structural characterization of a doubly deprotonated 1,1'-bis(o-carborane) anion [C2B10H10]2 2-, which is the first example of a discrete molecular dicarbanion. These reactive carbanions are key intermediates in carbon vertex chemistry of carborane clusters.
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Clean water, which is free from pathogens and toxic chemicals, is vital to human health. The blue planet is encountering remarkable challenges in meeting the ever-increasing demands of clean water. The intention of this research study was to develop a water filter material that is capable of removing bacterial contaminants and heavy metals from fresh water using cost effective and easily fabricated biocompatible filter material. For this purpose, granular activated carbon (GAC) was coated with both hydroxyapatite (HAP) nanoflakes and turmeric extract (TE) (HAP/TE/GAC) which had been extracted from natural turmeric powder. In addition, GAC was coated only with HAP nanoflakes to synthesize HAP coated GAC (HAP/GAC) composite. Prepared HAP/GAC and HAP/TE/GAC were characterized using Fourier-transform infrared spectroscopy, X-ray diffractometry, scanning electron microscopy and UV-visible spectrophotometry. Antibacterial effect of the prepared nanocomposites, HAP/GAC and HAP/TE/GAC was compared with neat GAC using Gram-negative bacteria Escherichia coli. Results showed that antibacterial studies of the synthesized nanocomposites exhibit effective antibacterial activity against E. coli compared with neat GAC alone. However, the composite HAP/TE/GAC revealed better activity than HAP/GAC. Heavy metal adsorption ability of the synthesized composites was carried out using Pb2+ ions at room temperature at different time intervals and different pH levels. The equilibrium adsorption data were assessed via Langmuir and Freundlich adsorption isotherm models for neat GAC, HAP/GAC and HAP/TE/GAC at pH 6. The equilibrium adsorption data for GAC, HAP/GAC and HAP/TE/GAC were well fitted with both Freundlich and Langmuir isotherm models in the given Pb2+ concentrations. The HAP/TE/GAC composite is capable of maintaining the natural function of GAC in addition to removal of bacterial contaminants and heavy metals, which can be used as a point-of-use water filter material.