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1.
Nature ; 580(7805): 621-627, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32179876

RESUMO

Frequently referred to as the 'magic methyl effect', the installation of methyl groups-especially adjacent (α) to heteroatoms-has been shown to dramatically increase the potency of biologically active molecules1-3. However, existing methylation methods show limited scope and have not been demonstrated in complex settings1. Here we report a regioselective and chemoselective oxidative C(sp3)-H methylation method that is compatible with late-stage functionalization of drug scaffolds and natural products. This combines a highly site-selective and chemoselective C-H hydroxylation with a mild, functional-group-tolerant methylation. Using a small-molecule manganese catalyst, Mn(CF3PDP), at low loading (at a substrate/catalyst ratio of 200) affords targeted C-H hydroxylation on heterocyclic cores, while preserving electron-neutral and electron-rich aryls. Fluorine- or Lewis-acid-assisted formation of reactive iminium or oxonium intermediates enables the use of a mildly nucleophilic organoaluminium methylating reagent that preserves other electrophilic functionalities on the substrate. We show this late-stage C(sp3)-H methylation on 41 substrates housing 16 different medicinally important cores that include electron-rich aryls, heterocycles, carbonyls and amines. Eighteen pharmacologically relevant molecules with competing sites-including drugs (for example, tedizolid) and natural products-are methylated site-selectively at the most electron rich, least sterically hindered position. We demonstrate the syntheses of two magic methyl substrates-an inverse agonist for the nuclear receptor RORc and an antagonist of the sphingosine-1-phosphate receptor-1-via late-stage methylation from the drug or its advanced precursor. We also show a remote methylation of the B-ring carbocycle of an abiraterone analogue. The ability to methylate such complex molecules at late stages will reduce synthetic effort and thereby expedite broader exploration of the magic methyl effect in pursuit of new small-molecule therapeutics and chemical probes.


Assuntos
Produtos Biológicos/química , Produtos Biológicos/síntese química , Carbono/química , Técnicas de Química Sintética , Hidrogênio/química , Preparações Farmacêuticas/química , Preparações Farmacêuticas/síntese química , Androstenos/síntese química , Androstenos/química , Catálise , Agonismo Inverso de Drogas , Elétrons , Flúor/química , Hidroxilação , Ácidos de Lewis/química , Manganês/química , Metilação , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/agonistas , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/antagonistas & inibidores , Oxazolidinonas/síntese química , Oxazolidinonas/química , Oxirredução , Receptores de Esfingosina-1-Fosfato/antagonistas & inibidores , Tetrazóis/síntese química , Tetrazóis/química
2.
Proc Natl Acad Sci U S A ; 120(29): e2300315120, 2023 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-37428920

RESUMO

An emerging trend in small-molecule pharmaceuticals, generally composed of nitrogen heterocycles (N-heterocycles), is the incorporation of aliphatic fragments. Derivatization of the aliphatic fragments to improve drug properties or identify metabolites often requires lengthy de novo syntheses. Cytochrome P450 (CYP450) enzymes are capable of direct site- and chemo-selective oxidation of a broad range of substrates but are not preparative. A chemoinformatic analysis underscored limited structural diversity of N-heterocyclic substrates oxidized using chemical methods relative to pharmaceutical chemical space. Here, we describe a preparative chemical method for direct aliphatic oxidation that tolerates a wide range of nitrogen functionality (chemoselective) and matches the site of oxidation (site-selective) of liver CYP450 enzymes. Commercial small-molecule catalyst Mn(CF3-PDP) selectively effects direct methylene oxidation in compounds bearing 25 distinct heterocycles including 14 out of 27 of the most frequent N-heterocycles found in U.S. Food and Drug Administration (FDA)-approved drugs. Mn(CF3-PDP) oxidations of carbocyclic bioisostere drug candidates (for example, HCV NS5B and COX-2 inhibitors including valdecoxib and celecoxib derivatives) and precursors of antipsychotic drugs blonanserin, buspirone, and tiospirone and the fungicide penconazole are demonstrated to match the major site of aliphatic metabolism obtained with liver microsomes. Oxidations are demonstrated at low Mn(CF3-PDP) loadings (2.5 to 5 mol%) on gram scales of substrate to furnish preparative amounts of oxidized products. A chemoinformatic analysis supports that Mn(CF3-PDP) significantly expands the pharmaceutical chemical space accessible to small-molecule C-H oxidation catalysis.


Assuntos
Sistema Enzimático do Citocromo P-450 , Fígado , Oxirredução , Sistema Enzimático do Citocromo P-450/química , Preparações Farmacêuticas/química , Catálise , Microssomos Hepáticos , Nitrogênio
3.
Int J Behav Nutr Phys Act ; 20(1): 64, 2023 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-37259093

RESUMO

BACKGROUND: There is limited evidence on what shapes the acceptability of population level dietary and active-travel policies in England. This information would be useful in the decision-making process about which policies should be implemented and how to increase their effectiveness and sustainability. To fill this gap, we explored public and policymakers' views about factors that influence public acceptability of dietary and active-travel policies and how to increase public acceptability for these policies. METHODS: We conducted online, semi-structured interviews with 20 members of the public and 20 policymakers in England. A purposive sampling frame was used to recruit members of the public via a recruitment agency, based on age, sex, socioeconomic status and ethnicity. Policymakers were recruited from existing contacts within our research collaborations and via snowball sampling. We explored different dietary and active-travel policies that varied in their scope and focus. Interviews were transcribed verbatim and analysed using thematic reflexive analysis with both inductive and deductive coding. RESULTS: We identified four themes that informed public acceptability of dietary and active-travel policies: (1) perceived policy effectiveness, i.e., policies that included believable mechanisms of action, addressed valued co-benefits and barriers to engage in the behaviour; (2) perceived policy fairness, i.e., policies that provided everyone with an opportunity to benefit (mentioned only by the public), equally considered the needs of various population subgroups and rewarded 'healthy' behaviours rather than only penalising 'unhealthy' behaviours; (3) communication of policies, i.e., policies that were visible and had consistent and positive messages from the media (mentioned only by policymakers) and (4) how to improve policy support, with the main suggestion being an integrated strategy addressing multiple aspects of these behaviours, inclusive policies that consider everyone's needs and use of appropriate channels and messages in policy communication. CONCLUSIONS: Our findings highlight that members' of the public and policymakers' support for dietary and active-travel policies can be shaped by the perceived effectiveness, fairness and communication of policies and provide suggestions on how to improve policy support. This information can inform the design of acceptable policies but can also be used to help communicate existing and future policies to maximise their adoption and sustainability.


Assuntos
Dieta , Política de Saúde , Humanos , Pesquisa Qualitativa , Formulação de Políticas , Comunicação
4.
J Public Health (Oxf) ; 45(2): e266-e274, 2023 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-36321614

RESUMO

BACKGROUND: Screening options for pancreatic ductal adenocarcinoma (PDAC) are limited. New-onset type 2 diabetes (NoD) is associated with subsequent diagnosis of PDAC in observational studies and may afford an opportunity for PDAC screening. We evaluated this association using a large administrative database. METHODS: Patients were identified using claims data from the OptumLabs® Data Warehouse. Adult patients with NoD diagnosis were matched 1:3 with patients without NoD using age, sex and chronic obstructive pulmonary disease (COPD) status. The event of PDAC diagnosis was compared between cohorts using the Kaplan-Meier method. Factors associated with PDAC diagnosis were evaluated with Cox's proportional hazards modeling. RESULTS: We identified 640 421 patients with NoD and included 1 921 263 controls. At 3 years, significantly more PDAC events were identified in the NoD group vs control group (579 vs 505; P < 0.001). When controlling for patient factors, NoD was significantly associated with elevated risk of PDAC (HR 3.474, 95% CI 3.082-3.920, P < 0.001). Other factors significantly associated with PDAC diagnosis were increasing age, increasing age among Black patients, and COPD diagnosis (P ≤ 0.05). CONCLUSIONS: NoD was independently associated with subsequent diagnosis of PDAC within 3 years. Future studies should evaluate the feasibility and benefit of PDAC screening in patients with NoD.


Assuntos
Carcinoma Ductal Pancreático , Diabetes Mellitus Tipo 2 , Neoplasias Pancreáticas , Adulto , Humanos , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/complicações , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/epidemiologia , Neoplasias Pancreáticas/complicações , Carcinoma Ductal Pancreático/diagnóstico , Carcinoma Ductal Pancreático/epidemiologia , Carcinoma Ductal Pancreático/complicações , Estudos Retrospectivos , Neoplasias Pancreáticas
5.
Nature ; 537(7619): 214-219, 2016 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-27479323

RESUMO

Secondary metabolites synthesized by non-ribosomal peptide synthetases display diverse and complex topologies and possess a range of biological activities. Much of this diversity derives from a synthetic strategy that entails pre- and post-assembly oxidation of both the chiral amino acid building blocks and the assembled peptide scaffolds. The vancomycin biosynthetic pathway is an excellent example of the range of oxidative transformations that can be performed by the iron-containing enzymes involved in its biosynthesis. However, because of the challenges associated with using such oxidative enzymes to carry out chemical transformations in vitro, chemical syntheses guided by these principles have not been fully realized in the laboratory. Here we report that two small-molecule iron catalysts are capable of facilitating the targeted C-H oxidative modification of amino acids and peptides with preservation of α-centre chirality. Oxidation of proline to 5-hydroxyproline furnishes a versatile intermediate that can be transformed to rigid arylated derivatives or flexible linear carboxylic acids, alcohols, olefins and amines in both monomer and peptide settings. The value of this C-H oxidation strategy is demonstrated in its capacity for generating diversity: four 'chiral pool' amino acids are transformed to twenty-one chiral unnatural amino acids representing seven distinct functional group arrays; late-stage C-H functionalizations of a single proline-containing tripeptide furnish eight tripeptides, each having different unnatural amino acids. Additionally, a macrocyclic peptide containing a proline turn element is transformed via late-stage C-H oxidation to one containing a linear unnatural amino acid.


Assuntos
Aminoácidos/química , Aminoácidos/síntese química , Ferro/química , Ferro/farmacologia , Peptídeos/química , Peptídeos/síntese química , Catálise/efeitos dos fármacos , Hidroxilação/efeitos dos fármacos , Compostos Macrocíclicos/química , Estrutura Molecular , Prolina/química , Estereoisomerismo
6.
Appetite ; 174: 106045, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35427706

RESUMO

Interventions that promote responsive feeding in early childhood have been shown to reduce obesity risks. However, interventions mostly target parent-child dyads without considering the complexities of implementing responsive feeding across multiple children within a family unit. This scoping review aims to assess the extent and nature of current literature examining feeding in the context of siblings. Six electronic databases were searched (APA PsycINFO, CINAHL, Embase, Medline, ProQuest Dissertations & Theses Global, and Scopus) for articles published up until November 25, 2021. Studies were included if they compared the use of parent feeding practices and/or styles for two or more siblings aged ≤18 years. Data were extracted from relevant studies and analysed using basic descriptive statistics. A total of 18 studies from North America (n = 12) and Europe (n = 6) were included, with the majority targeting children between 6 and 18 years of age (n = 12). All studies were cross-sectional, with most designed to test differences in parent-reported feeding practices for siblings, primarily restriction and/or pressure to eat, in relation to differences in their characteristics (n = 12). The studies provide some evidence that parents may modify certain feeding practices or styles for siblings in response to differences in their characteristics, such as weight status and eating behaviours. Future research should examine processes that underlie feeding decisions in the context of siblings, including the contexts and consequences of differential feeding, with particular focus on early childhood when feeding interventions may be most effective.


Assuntos
Poder Familiar , Irmãos , Adolescente , Criança , Pré-Escolar , Comportamento Alimentar , Humanos , Pais , Verduras
7.
Ecotoxicology ; 31(2): 341-356, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35000026

RESUMO

Thiamethoxam is a neonicotinoid insecticide widely applied in the Canadian Prairies. It has been detected in surface waters of agro-ecosystems, including wetlands, but the potential effects on non-target invertebrate communities in these wetlands have not been well characterized. In an effort to understand better the fate of thiamethoxam in wetlands and the response of invertebrates (zooplankton and emergent insects), model systems were used to mimic wetland flooding into planted fields. Outdoor mesocosms were treated with a single application of thiamethoxam-treated canola seeds at three treatment levels based on a recommended seeding rate (i.e., 6 kg/ha; 1×, 10×, and 100× seeding rate) and monitored over ten weeks. The mean half-life of thiamethoxam in the water column was 6.2 d. There was no ecologically meaningful impact on zooplankton abundances or community structure among treatments. Statistically significant differences were observed in aquatic insect abundance between control mesocosms and the two greatest thiamethoxam treatments (10× and 100× seeding rate). The observed results indicate exposure to thiamethoxam at environmentally relevant concentrations likely does not represent a significant ecological risk to abundance and community structure of wetland zooplankton and emergent insects.


Assuntos
Inseticidas , Tiametoxam , Poluentes Químicos da Água , Animais , Canadá , Ecossistema , Inseticidas/análise , Inseticidas/toxicidade , Invertebrados , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Dinâmica Populacional , Tiametoxam/análise , Tiametoxam/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
8.
Metrologia ; 59(4)2022.
Artigo em Inglês | MEDLINE | ID: mdl-36733421

RESUMO

We have developed generalized methods for electrical substitution optical measurements, as well as cryogenic detectors which can be used to implement them. The new methods detailed here enable measurement of arbitrary periodic waveforms by an electrical substitution radiometer (ESR), which means that spectral and dynamic optical power can be absolutely calibrated directly by a primary standard detector. Cryogenic ESRs are not often used directly by researchers for optical calibrations due to their slow response times and cumbersome operation. We describe two types of ESRs with fast response times, including newly developed cryogenic bolometers with carbon nanotube absorbers, which are manufacturable by standard microfabrication techniques. These detectors have response times near 10 ms, spectral coverage from the ultraviolet to far-infrared, and are ideal for use with generalized electrical substitution. In our first tests of the generalized electrical substitution method with FTS, we have achieved uncertainty in detector response of 0.13 % (k=1) and total measurement uncertainty of 1.1 % (k=1) in the mid-infrared for spectral detector responsivity calibrations. The generalized method and fast detectors greatly expand the range of optical power calibrations which can be made using a wideband primary standard detector, which can shorten calibration chains and improve uncertainties.

9.
Public Health ; 211: 1-4, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35985222

RESUMO

OBJECTIVES: We aimed to identify when and how integration should take place within evaluations of complex population health interventions (PHIs). STUDY DESIGN: Descriptive analytical approach. METHODS: We draw on conceptual insights that emerged through (1) a working group on integration and (2) a diverse range of literature on case studies, small-n evaluations and mixed methods evaluation studies. RESULTS: We initially sought techniques to integrate analyses at the end of a complex PHI evaluation. However, this conceptualization of integration proved limiting. Instead, we found value in conceptualizing integration as a process that commences at the beginning of an evaluation and continues throughout. Many methods can be used for this type of integration, including process tracing, realist evaluation, congruence analysis, general elimination methodology/modus operandi, pattern matching and contribution analysis. Clearly signposting when integrative methods should commence within an evaluation should be of value to the PHI evaluation community, as well as to funders and related stakeholders. CONCLUSIONS: Rather than being a tool used at the end of an evaluation, we propose that integration is more usefully conceived as a process that commences at the start of an evaluation and continues throughout. To emphasize the importance of this timing, integration can be described as comprising 'Work Package Zero' within evaluations of complex PHIs.


Assuntos
Saúde da População , Projetos de Pesquisa , Atenção à Saúde , Humanos , Inquéritos e Questionários
10.
J Am Chem Soc ; 143(37): 14969-14975, 2021 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-34514799

RESUMO

Allylic amination enables late-stage functionalization of natural products where allylic C-H bonds are abundant and introduction of nitrogen may alter biological profiles. Despite advances, intermolecular allylic amination remains a challenging problem due to reactivity and selectivity issues that often mandate excess substrate, furnish product mixtures, and render important classes of olefins (for example, functionalized cyclic) not viable substrates. Here we report that a sustainable manganese perchlorophthalocyanine catalyst, [MnIII(ClPc)], achieves selective, preparative intermolecular allylic C-H amination of 32 cyclic and linear compounds, including ones housing basic amines and competing sites for allylic, ethereal, and benzylic amination. Mechanistic studies support that the high selectivity of [MnIII(ClPc)] may be attributed to its electrophilic, bulky nature and stepwise amination mechanism. Late-stage amination is demonstrated on five distinct classes of natural products, generally with >20:1 site-, regio-, and diastereoselectivity.


Assuntos
Aminas , Complexos de Coordenação , Aminação , Aminas/síntese química , Aminas/química , Catálise , Estrutura Molecular , Complexos de Coordenação/química
11.
Adv Exp Med Biol ; 1269: 45-49, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33966193

RESUMO

This case report describes a major surgical procedure for a protein C-deficient, hypercoagulable patient who underwent two back-to-back invasive surgeries, hip replacement, and spinal stenosis correction. The patient, an 84-year-old male with a history of deep vein thromboses (DVT) and pulmonary emboli (PE), was treated pre-, peri-, and postoperatively with zymogen protein C (ZPC-Baxter, International) and recovered without clotting or increased bleeding. During the procedure, the patient was not administered any other anticoagulants. There have now been several case reports on different patients with unrelated teams in various locations worldwide using zymogen protein C during surgical procedures. Thus, this procedure is becoming a viable choice for patients with a high probability of clotting during and after invasive surgery. This case focuses on accomplishing safer surgery and reducing costs, by using less ZPC while accomplishing two surgeries in one procedure. As a result, this procedure might be useful for many medical situations where acquired protein C deficiency could be a problem (e.g., sepsis, pregnancy, etc.). This approach may have greater application to medical conditions other than protein C deficiency, where clotting and inflammation can become issues.


Assuntos
Deficiência de Proteína C , Proteína C , Idoso de 80 Anos ou mais , Anticoagulantes/uso terapêutico , Precursores Enzimáticos , Humanos , Masculino , Segurança do Paciente
12.
Proc Natl Acad Sci U S A ; 115(22): E5243-E5249, 2018 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-29760065

RESUMO

NF-κB signaling plays a pivotal role in control of the inflammatory response. We investigated how the dynamics and function of NF-κB were affected by temperature within the mammalian physiological range (34 °C to 40 °C). An increase in temperature led to an increase in NF-κB nuclear/cytoplasmic oscillation frequency following Tumor Necrosis Factor alpha (TNFα) stimulation. Mathematical modeling suggested that this temperature sensitivity might be due to an A20-dependent mechanism, and A20 silencing removed the sensitivity to increased temperature. The timing of the early response of a key set of NF-κB target genes showed strong temperature dependence. The cytokine-induced expression of many (but not all) later genes was insensitive to temperature change (suggesting that they might be functionally temperature-compensated). Moreover, a set of temperature- and TNFα-regulated genes were implicated in NF-κB cross-talk with key cell-fate-controlling pathways. In conclusion, NF-κB dynamics and target gene expression are modulated by temperature and can accurately transmit multidimensional information to control inflammation.


Assuntos
Regulação da Expressão Gênica/fisiologia , NF-kappa B/metabolismo , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Linhagem Celular Tumoral , Células Cultivadas , Citocinas/metabolismo , Regulação da Expressão Gênica/genética , Técnicas de Silenciamento de Genes , Humanos , Inflamação , Camundongos , NF-kappa B/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Temperatura , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/análise , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/genética
13.
Opt Express ; 28(10): 15331-15346, 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32403563

RESUMO

We demonstrate the capability to measure the absolute power responsivity of optical fiber-coupled detectors at an expanded uncertainty of 0.1%, by direct comparison with a cryogenic primary standard. To facilitate synchronous power measurements, commercial all-fiber beam-splitters direct laser diode light simultaneously to the device under test and the primary standard. We investigate the use of single-mode, polarisation maintaining, and photonic crystal fibers to access the cryogenic standard, and report a reduction in the temperature dependent effective refractive index of these fibers of 0.1%, 0.15% and 0.3% respectively in going from room temperature to 5 K. We also evaluate the polarisation dependent loss of the beam-splitters, the stability of the beam-splitter ratio between the cryogenic detector and the device under test and the temporal and modal stability of the Fabry-Pérot laser diode sources. It is shown that the stability of the optical fiber beam-splitters limits the overall performance of the measurement system to an expanded uncertainty of 0.1%.

14.
Diabet Med ; 37(3): 401-408, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31797439

RESUMO

Disordered eating is a serious and under-recognized problem in people with diabetes. This narrative review summarizes the research contributions made by psychological science over the past 25 years to the study of disordered eating in people with type 1 or type 2 diabetes, and identifies gaps and future directions relevant to both healthcare professionals and researchers. Key focus areas of psychological research investigating disordered eating in people with diabetes have been: (1) defining and classifying types of disordered eating; (2) identifying demographic, diabetes-specific and psychosocial correlates of disordered eating, and developing theoretical models of disordered eating in people with type 1 diabetes; (3) identifying the physical and psychosocial consequences of disordered eating; and (4) developing screening measures to identify disordered eating in people with type 1 diabetes. Psychological science has made significant contributions over the past 25 years to our understanding of the nature of this problem and the multiple factors which may interrelate with disordered eating in people with diabetes. Key areas for further attention include: (1) a better definition of disordered eating subtypes in people with type 1 diabetes; (2) characterizing disordered eating in people with type 2 diabetes; and (3) developing multidisciplinary, evidence-based prevention and treatment interventions for comorbid disordered eating and diabetes.


Assuntos
Pesquisa Comportamental , Complicações do Diabetes , Transtornos da Alimentação e da Ingestão de Alimentos/complicações , Psicologia , Pesquisa Comportamental/história , Pesquisa Comportamental/métodos , Pesquisa Comportamental/tendências , Pesquisa Biomédica/história , Pesquisa Biomédica/métodos , Pesquisa Biomédica/tendências , Complicações do Diabetes/epidemiologia , Complicações do Diabetes/etiologia , Complicações do Diabetes/psicologia , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/epidemiologia , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/psicologia , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/psicologia , Transtornos da Alimentação e da Ingestão de Alimentos/epidemiologia , Transtornos da Alimentação e da Ingestão de Alimentos/psicologia , História do Século XX , História do Século XXI , Humanos , Psicologia/história , Psicologia/métodos , Psicologia/tendências
15.
Adv Synth Catal ; 362(2): 417-423, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-32165875

RESUMO

Aromatic and heterocyclic functionality are ubiquitous in pharmaceuticals. Herein, we disclose a new Mn(PDP)catalyst system using chloroacetic acid additive capable of chemoselectively oxidizing remote tertiary C(sp 3)-H bonds in the presence of a broad range of aromatic and heterocyclic moieties. Although catalyst loadings can be lowered to 0.1 mol% under a Mn(PDP)/acetic acid system for aromatic and non-basic nitrogen heterocycle substrates, the Mn(PDP)/chloroacetic acid system generally affords 10-15% higher isolated yields on these substrates and is uniquely effective for remote C(sp 3)-H hydroxylations in substrates housing basic nitrogen heterocycles. The demonstrated ability to perform Mn(PDP)/chloroacetic acid C(sp 3)-H oxidations in pharmaceutically relevant complex molecules on multi-gram scales will facilitate drug discovery processes via late-stage functionalization.

16.
J Environ Manage ; 261: 110210, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32148280

RESUMO

A relatively large number of studies have investigated the effectiveness of vegetated buffer strips at reducing the movement of pesticides and nutrients from agriculture fields. This review outlines the observed influence of different factors (e.g., buffer width, slope, runoff intensity, soil composition, plant community) that can influence the efficacy of vegetated buffers in pesticide and nutrient retention. The reported effectiveness of vegetated buffers reducing the movement of pesticides and nutrients ranged from 10 to 100% and 12-100%, respectively. Buffer width is the factor that is most frequently considered by various jurisdictions when making recommendations on vegetated buffer strip implementation. However, the literature clearly illustrates that there is a great deal of variation in pesticide or nutrient reduction for a given buffer width. This indicates that other factors play an important role in buffer efficacy (e.g., ratio of source area to buffer area, soil composition and structure, runoff intensity, plant community structure) in addition to the width of the vegetative buffer area. These factors need to be considered when making recommendations on vegetated buffer strip construction in agroecosystems. This review has also identified a number of other gaps in the understanding of the effectiveness of vegetated buffers at reducing the movement of pesticides and nutrients from the areas of application.


Assuntos
Praguicidas , Poluentes Químicos da Água , Agricultura , Nutrientes , Plantas
17.
J Am Chem Soc ; 141(24): 9468-9473, 2019 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-31140795

RESUMO

We report the development of a Pd(II)/(±)-MeO-SOX/2,5-dimethylbenzoquinone system that enables unprecedented access to anti-1,3 amino alcohol motifs in good yields (33 substrates, avg. 66% isolated yield, >20:1 dr) and high selectivities (avg. 10:1 dr). Switching ligands to (±)-CF3-SOX with the use of a less bulky quinone oxidant, the kinetic syn-1,3 amino alcohol motif can be accessed in comparable yields and selectivities. Advantages of the stereodivergent nature of this reaction are seen in the synthesis of anti- and syn-1,3 amino alcohol vitamin D3 analogue intermediates in half the steps and higher overall yield relative to previous routes. Additionally, all eight possible stereoisomers of a chiral diamino alcohol core are generated from two amino acids. Mechanistic studies reveal that the anti-isomer is furnished through concurrent Pd(II)(SOX) catalyzed C-H amination and Pd(0)(SOX) catalyzed isomerization cycles.


Assuntos
Compostos Organoplatínicos/química , Oxazinas/síntese química , Sulfóxidos/química , Alcenos/química , Amino Álcoois/síntese química , Benzoquinonas/química , Catálise , Estereoisomerismo
19.
Opt Express ; 27(14): 19141-19149, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31503677

RESUMO

A cavity ringdown system for probing the spatial variation of optical loss across high-reflectivity mirrors is described. This system is employed to examine substrate-transferred crystalline supermirrors and to quantify the effect of manufacturing process imperfections. Excellent agreement is observed between the ringdown-generated spatial measurements and differential interference contrast microscopy images. A 2-mm diameter ringdown scan in the center of a crystalline supermirror reveals highly uniform coating properties with excess loss variations below 1 ppm.

20.
Br J Surg ; 106(2): e91-e102, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30620076

RESUMO

BACKGROUND: The WHO Surgical Safety Checklist improves surgical outcomes, but evidence and theoretical frameworks for successful implementation in low-income countries remain lacking. Based on previous research in Madagascar, a nationwide checklist implementation in Benin was designed and evaluated longitudinally. METHODS: This study had a longitudinal embedded mixed-methods design. The well validated Consolidated Framework for Implementation Research (CFIR) was used to structure the approach and evaluate the implementation. Thirty-six hospitals received 3-day multidisciplinary training and 4-month follow-up. Seventeen hospitals were sampled purposively for evaluation at 12-18 months. The primary outcome was sustainability of checklist use at 12-18 months measured by questionnaire. Secondary outcomes were CFIR-derived implementation outcomes, measured using the WHO Behaviourally Anchored Rating Scale (WHOBARS), safety questionnaires and focus groups. RESULTS: At 12-18 months, 86·0 per cent of participants (86 of 100) reported checklist use compared with 31·1 per cent (169 of 543) before training and 88·8 per cent (158 of 178) at 4 months. There was high-fidelity use (median WHOBARS score 5·0 of 7; use of basic safety processes ranged from 85·0 to 99·0 per cent), and high penetration shown by a significant improvement in hospital safety culture (adapted Human Factors Attitude Questionnaire scores of 76·7, 81·1 and 82·2 per cent before, and at 4 and 12-18 months after training respectively; P < 0·001). Acceptability, adoption, appropriateness and feasibility scored 9·6-9·8 of 10. This approach incorporated 31 of 36 CFIR implementation constructs successfully. CONCLUSION: This study shows successfully sustained nationwide checklist implementation using a validated implementation framework.


Assuntos
Lista de Checagem/métodos , Atenção à Saúde/normas , Implementação de Plano de Saúde/métodos , Segurança do Paciente/normas , Melhoria de Qualidade/estatística & dados numéricos , Benin , Lista de Checagem/estatística & dados numéricos , Seguimentos , Fidelidade a Diretrizes/estatística & dados numéricos , Hospitais/normas , Humanos , Estudos Longitudinais , Avaliação de Programas e Projetos de Saúde , Inquéritos e Questionários , Organização Mundial da Saúde
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