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1.
Opt Express ; 32(4): 5380-5396, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38439266

RESUMO

We present the development of a transportable laser frequency stabilization system with application to both optical clocks and a next-generation gravity mission (NGGM) in space. This effort leverages a 5-cm long cubic cavity with crystalline coatings operating at room temperature and with a center wavelength of 1064 nm. The cavity is integrated in a custom vacuum chamber with dedicated low-noise locking electronics. Our vacuum-mounted cavity and control system are well suited for space applications, exhibiting state-of-the-art noise performance while being resilient to radiation exposure, vibration, shock, and temperature variations. Furthermore, we demonstrate a robust means of automatically (re)locking the laser to the cavity when resonance is lost. We show that the mounted cavity is capable of reaching technology readiness level (TRL) 6, paving the way for high-performance ultrastable laser systems and eventually optical atomic clocks amenable to future satellite platforms.

2.
Mol Cell ; 63(1): 7-20, 2016 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-27392145

RESUMO

In modern molecular biology, RNA has emerged as a versatile macromolecule capable of mediating an astonishing number of biological functions beyond its role as a transient messenger of genetic information. The recent discovery and functional analyses of new classes of noncoding RNAs (ncRNAs) have revealed their widespread use in many pathways, including several in the nucleus. This Review focuses on the mechanisms by which nuclear ncRNAs directly contribute to the maintenance of genome stability. We discuss how ncRNAs inhibit spurious recombination among repetitive DNA elements, repress mobilization of transposable elements (TEs), template or bridge DNA double-strand breaks (DSBs) during repair, and direct developmentally regulated genome rearrangements in some ciliates. These studies reveal an unexpected repertoire of mechanisms by which ncRNAs contribute to genome stability and even potentially fuel evolution by acting as templates for genome modification.


Assuntos
Núcleo Celular/metabolismo , Instabilidade Genômica , RNA não Traduzido/genética , Animais , Quebras de DNA de Cadeia Dupla , Reparo do DNA , Dosagem de Genes , Inativação Gênica , Heterocromatina/genética , Heterocromatina/metabolismo , Humanos , Conformação de Ácido Nucleico , RNA não Traduzido/química , RNA não Traduzido/classificação , RNA não Traduzido/metabolismo , Relação Estrutura-Atividade , Telômero/genética , Telômero/metabolismo
3.
Small ; 19(35): e2207100, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37098606

RESUMO

Materials are more easily damaged during accidents that involve rapid deformation. Here, a design strategy is described for electronic materials comprised of conducting polymers that defies this orthodox property, making their extensibility and toughness dynamically adaptive to deformation rates. This counterintuitive property is achieved through a morphology of interconnected nanoscopic core-shell micelles, where the chemical interactions are stronger within the shells than the cores. As a result, the interlinked shells retain material integrity under strain, while the rate of dissociation of the cores controls the extent of micelle elongation, which is a process that adapts to deformation rates. A prototype based on polyaniline shows a 7.5-fold increase in ultimate elongation and a 163-fold increase in toughness when deformed at increasing rates from 2.5 to 10 000% min-1 . This concept can be generalized to other conducting polymers and highly conductive composites to create "self-protective" soft electronic materials with enhanced durability under dynamic movement or deformation.

4.
Health Expect ; 26(6): 2655-2665, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37697688

RESUMO

OBJECTIVES: To explore the perceptions of patients and healthcare professionals on Raman-faecal immunochemical test (FIT) as an alternative test for colorectal cancer exclusion in primary care. DESIGN: Semi-structured interviews within a feasibility study. SETTING: Patients presenting to primary care with colorectal symptoms and healthcare professionals working in primary and secondary care. PARTICIPANTS: A total of 23 patients and 12 healthcare professionals. METHODS: Patient participants were asked to complete a novel combined Raman-FIT test before being seen in secondary care. This study sought their opinions about the test. We also sought the views of healthcare professionals. FINDINGS: Patients and healthcare professionals agreed that Raman-FIT was a suitable test to be given in primary care. It aligned with routine practice and was a simple test for most patients to complete. CONCLUSIONS: Patients are willing and able to complete the Raman-FIT test in primary care. Raman-FIT may accelerate access to diagnosis with the potential to improve cancer outcomes. PATIENT AND PUBLIC INVOLVEMENT: Lay members (J. H. and I. H.) with experience and knowledge of colorectal cancer and screening contributed to developing, undertaking, and disseminating all aspects of the research. They were supported to collaborate as equal members of the research team. They were involved in developing the study as coapplicants, using personal experience to ensure that the research and its methods were relevant to the patient and public needs. Both prepared participant information sheets, coanalysed data, and contributed to study reporting and dissemination through papers, conference presentations and a lay summary.


Assuntos
Neoplasias Colorretais , Sangue Oculto , Humanos , Neoplasias Colorretais/diagnóstico , Atenção à Saúde , Atenção Primária à Saúde , Detecção Precoce de Câncer/métodos
5.
Prev Med ; 164: 107240, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36063876

RESUMO

Maternity Care Homes (MCHs) intend to address clinical and psychosocial needs for perinatal patients and are commonly implemented for Medicaid beneficiaries. Rigorous evidence supporting MCHs' effectiveness for improving birth outcomes is thin, but most studies consider only clinical and demographic factors from administrative data. To assess birth outcomes with controls for psychosocial variables known to affect them, this paper considers quantitative participant-level data from the Strong Start for Mothers and Newborns prenatal care initiative, with qualitative case study data to further contextualize results. From 2013 to 2017, Strong Start served over 45,000 Medicaid beneficiaries in 32 states, D.C., and Puerto Rico though MCHs, group prenatal care, or freestanding birth centers. Participant data included risks screens for food insecurity, depression, anxiety, pregnancy intention, and intimate partner violence, in addition to clinical and demographic information. After clinical, demographic and psychosocial risks were controlled in a regression model, Strong Start birth center participants showed significantly lower rates of preterm birth, low birthweight, and cesarean section relative to MCH participants (p < .01). In group prenatal care, White participants showed lower rates of preterm birth (p < .01) and Black participants showed lower rates of low birthweight (p < .05) relative to MCH participants. Strong Start participants reported appreciation for MCH care managers' support, but community and clinical referrals often had long waiting lists or were inaccessible. Transformative care models focusing on provider continuity, relationship building, and patient activation may offer more promise for improving birth outcomes than supplementing medical models with care management and other resources.


Assuntos
Serviços de Saúde Materna , Nascimento Prematuro , Recém-Nascido , Feminino , Gravidez , Estados Unidos , Humanos , Cuidado Pré-Natal , Medicaid , Cesárea , Peso ao Nascer
6.
Opt Express ; 29(22): 36758-36768, 2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34809079

RESUMO

We describe a 'clock control unit' based on a dual-axis cubic cavity (DACC) for the frequency stabilisation of lasers involved in a strontium optical lattice clock. The DACC, which ultimately targets deployment in space applications, provides a short-term stable reference for all auxiliary lasers-i.e. cooling, clear-out, and optical lattice-in a single multi-band cavity. Long-term cavity drift is compensated by a feed-forward scheme exploiting a fixed physical relation to an orthogonal second cavity axis; either by reference to an ultrastable 698 nm clock laser, or by exploiting the differential drift between orthogonal axes extracted by a single laser in common view. Via a change of mirror set in the cavity axis accessed by the clock laser, the system could also provide stabilisation for sub-Hz linewidths at the 698 nm clock wavelength, fulfilling all stabilisation requirements of the clock.

7.
J Surg Res ; 264: 490-498, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33857793

RESUMO

BACKGROUND: Surgical instrument tray reduction attempts to minimize intraoperative inefficiency and processing costs. Previous reduction methods relied on trained observers manually recording instrument use (i.e. human ethnography), and surgeon and/or staff recall, which are imprecise and inherently limited. We aimed to determine the feasibility of radiofrequency identification (RFID)-based intraoperative instrument tracking as an effective means of instrument reduction. METHODS: Instrument trays were tagged with unique RFID tags. A RFID reader tracked instruments passing near RFID antennas during 15 breast operations performed by a single surgeon; ethnography was performed concurrently. Instruments without recorded use were eliminated, and 10 additional cases were performed utilizing the reduced tray. Logistic regression was used to estimate odds of instrument use across cases. Cohen's Kappa estimated agreement between RFID and ethnography. RESULTS: Over 15 cases, 37 unique instruments were used (median 23 instruments/case). A mean 0.64 (median = 0, range = 0-3) new instruments were added per case; odds of instrument use did not change between cases (OR = 1.02, 95%CI 1.00-1.05). Over 15 cases, all instruments marked as used by ethnography were recorded by RFID tracking; 7 RFID-tracked instruments were never recorded by ethnography. Tray size was reduced 40%. None of the 25 eliminated instruments were required in 10 subsequent cases. Cohen's Kappa comparing RFID data and ethnography over all cases was 0.82 (95%CI 0.79-0.86), indicating near perfect agreement between methodologies. CONCLUSIONS: Intraoperative RFID instrument tracking is a feasible, data-driven method for surgical tray reduction. Overall, RFID tracking represents a scalable, systematic, and efficient method of optimizing instrument supply across procedures.


Assuntos
Salas Cirúrgicas/provisão & distribuição , Dispositivo de Identificação por Radiofrequência , Instrumentos Cirúrgicos/provisão & distribuição , Oncologia Cirúrgica/organização & administração , Redução de Custos , Estudos de Viabilidade , Humanos , Salas Cirúrgicas/economia , Salas Cirúrgicas/organização & administração , Projetos Piloto , Instrumentos Cirúrgicos/economia , Oncologia Cirúrgica/economia , Oncologia Cirúrgica/instrumentação
8.
Milbank Q ; 98(4): 1091-1113, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32930433

RESUMO

Policy Points Birth center services must be covered under Medicaid per federal mandate, but reimbursement and other policy barriers prevent birth centers from serving more Medicaid patients. Midwifery care provided through birth centers improves maternal and infant outcomes and lowers costs for Medicaid beneficiaries. Birth centers offer an array of birth options and have resources to care for patients with medical and psychosocial risks. Addressing the barriers identified in this study would promote birth centers' participation in Medicaid, leading to better outcomes for Medicaid-covered mothers and newborns and significant savings for the Medicaid program. CONTEXT: Midwifery care, particularly when offered through birth centers, has shown promise in both improving pregnancy outcomes and containing costs. The national evaluation of Strong Start for Mothers and Newborns II, an initiative that tested enhanced prenatal care models for Medicaid beneficiaries, found that women receiving prenatal care at Strong Start birth centers experienced superior birth outcomes compared to matched and adjusted counterparts in typical Medicaid care. We use qualitative evaluation data to investigate birth centers' experiences participating in Medicaid, and identify policies that influence Medicaid beneficiaries' access to midwives and birth centers. METHODS: We analyzed data from more than 200 key informant interviews and 40 focus groups conducted during four case study rounds; a phone-based survey of Medicaid officials in Strong Start states; and an Internet-based survey of birth center sites. We identified themes related to access to midwives and birth centers, focusing on influential Medicaid policies. FINDINGS: Medicaid beneficiaries chose birth center care because they preferred midwife providers, wanted a more natural birth experience, or in some cases sought certain pain relief methods or birth procedures not available at hospitals. However, Medicaid enrollees currently have less access to birth centers than privately insured women. Many birth centers have difficulty contracting with managed care organizations and participating in Medicaid value-based delivery system reforms, and birth center reimbursement rates are sometimes too low to cover the actual cost of care. Some birth centers significantly limit Medicaid business because of low reimbursement rates and threats to facility sustainability. CONCLUSIONS: Medicaid beneficiaries do not have the same access to maternity care providers and birth settings as their privately insured counterparts. Medicaid policy barriers prevent some birth centers from serving more Medicaid patients, or threaten the financial sustainability of centers. By addressing these barriers, more Medicaid beneficiaries could access care that is associated with positive birth outcomes for mothers and newborns, and the Medicaid program could reap significant savings.


Assuntos
Centros de Assistência à Gravidez e ao Parto , Acessibilidade aos Serviços de Saúde , Serviços de Saúde Materno-Infantil/economia , Medicaid , Tocologia , Cuidado Pré-Natal , Feminino , Humanos , Serviços de Saúde Materno-Infantil/normas , Gravidez , Estados Unidos
9.
J Bacteriol ; 201(20)2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31358608

RESUMO

Hfq is an RNA chaperone that serves as a master regulator of bacterial physiology. Here we show that in the opportunistic pathogen Pseudomonas aeruginosa, the loss of Hfq can result in a dramatic reduction in growth in a manner that is dependent upon MexT, a transcription regulator that governs antibiotic resistance in this organism. Using a combination of chromatin immunoprecipitation with high-throughput sequencing and transposon insertion sequencing, we identify the MexT-activated genes responsible for mediating the growth defect of hfq mutant cells. These include a newly identified MexT-controlled gene that we call hilR We demonstrate that hilR encodes a small protein that is acutely toxic to wild-type cells when produced ectopically. Furthermore, we show that hilR expression is negatively regulated by Hfq, offering a possible explanation for the growth defect of hfq mutant cells. Finally, we present evidence that the expression of MexT-activated genes is dependent upon GshA, an enzyme involved in the synthesis of glutathione. Our findings suggest that Hfq can influence the growth of P. aeruginosa by limiting the toxic effects of specific MexT-regulated genes. Moreover, our results identify glutathione to be a factor important for the in vivo activity of MexT.IMPORTANCE Here we show that the conserved RNA chaperone Hfq is important for the growth of the opportunistic pathogen Pseudomonas aeruginosa We found that the growth defect of hfq mutant cells is dependent upon the expression of genes that are under the control of the transcription regulator MexT. These include a gene that we refer to as hilR, which we show is negatively regulated by Hfq and encodes a small protein that can be toxic when ectopically produced in wild-type cells. Thus, Hfq can influence the growth of P. aeruginosa by limiting the toxic effects of MexT-regulated genes, including one encoding a previously unrecognized small protein. We also show that MexT activity depends on an enzyme that synthesizes glutathione.


Assuntos
Fator Proteico 1 do Hospedeiro/genética , Mutação , Pseudomonas aeruginosa/crescimento & desenvolvimento , Transativadores/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Imunoprecipitação da Cromatina , Regulação Bacteriana da Expressão Gênica , Glutationa/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Viabilidade Microbiana , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo , Transativadores/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
10.
Opt Express ; 27(26): 37099-37110, 2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31878496

RESUMO

We demonstrate a new method of cavity-enhanced non-destructive detection of atoms for a strontium optical lattice clock. The detection scheme is shown to be linear in atom number up to at least 2×104 atoms, to reject technical noise sources, to achieve signal to noise ratio close to the photon shot noise limit, to provide spatially uniform atom-cavity coupling, and to minimize inhomogeneous ac Stark shifts. These features enable detection of atoms with minimal perturbation to the atomic state, a critical step towards realizing an ultra-high-stability, quantum-enhanced optical lattice clock.

11.
J Chem Phys ; 151(14): 144702, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31615224

RESUMO

Carrier scattering processes are studied in CH3NH3PbI3 using temperature-dependent four-wave mixing experiments. Our results indicate that scattering by ionized impurities limits the interband dephasing time (T2) below 30 K, with strong electron-phonon scattering dominating at higher temperatures (with a time scale of 125 fs at 100 K). Our theoretical simulations provide quantitative agreement with the measured carrier scattering rate and show that the rate of acoustic phonon scattering is enhanced by strong spin-orbit coupling, which modifies the band-edge density of states. The Rashba coefficient extracted from fitting the experimental results (γc = 2 eV Å) is in agreement with calculations of the surface Rashba effect and recent experiments using the photogalvanic effect on thin films.

12.
Birth ; 46(2): 244-252, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31087393

RESUMO

BACKGROUND: Medicaid pays for approximately half of United States births, yet little research has explored Medicaid beneficiaries' perspectives on their maternity care. Typical maternity care in the United States has been criticized as too medically focused while insufficiently addressing psychosocial risks and patient education. Enhanced care strives for a more holistic approach. METHODS: The perspectives of participants in the Strong Start for Mothers and Newborns II initiative, which provided enhanced prenatal care to women covered by Medicaid or the Children's Health Insurance Program (CHIP) during pregnancy through Birth Centers, Group Prenatal Care, and Maternity Care Homes, are evaluated. Strong Start intended to improve care quality and birth outcomes while lowering costs. We analyzed data from 133 focus groups with 951 pregnant or postpartum women who participated in Strong Start from 2013 to 2017. RESULTS: The majority of focus group participants said that Strong Start's enhanced care offered numerous important benefits over typical maternity care, including considerably more focus on women's psychosocial risk factors and need for education. They praised increased support; nutrition, breastfeeding, and family planning education; community referrals; longer time with practitioners; and involvement of partners in their care. Maternity Care Home participants, however, occasionally voiced concerns over lack of practitioner continuity and short clinical appointments, whereas Group Prenatal Care participants sometimes said they could not attend visits because of lack of childcare. CONCLUSIONS: Medicaid and CHIP beneficiaries reported positive experiences with Strong Start care. If more Medicaid practitioners could adopt aspects of the prenatal care approaches that women praised most, it is likely that women's risk factors could be more effectively addressed and their overall care experiences could be improved.


Assuntos
Medicaid , Satisfação do Paciente/estatística & dados numéricos , Nascimento Prematuro/prevenção & controle , Cuidado Pré-Natal/métodos , Adulto , Centros de Assistência à Gravidez e ao Parto , Centers for Medicare and Medicaid Services, U.S. , Feminino , Grupos Focais , Humanos , Recém-Nascido , Serviços de Saúde Materno-Infantil/organização & administração , Mães , Período Pós-Parto , Gravidez , Pesquisa Qualitativa , Fatores de Risco , Estados Unidos , Adulto Jovem
13.
Matern Child Health J ; 23(2): 285, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30506125

RESUMO

The original version of this article unfortunately contained a mistake in the order of authors. The co-author "Sarah Benatar" should be the second author and "Brigette Courtot" should be the third author of the article.

14.
Matern Child Health J ; 22(11): 1607-1616, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29956128

RESUMO

Objectives Strategies to prevent preterm birth are limited. 17 Alpha-Hydroxyprogesterone Caproate (17P) injections have been shown to be effective, but the intervention is under-used. This mixed methods study investigates barriers and facilitators to 17P administration among Medicaid and CHIP participants enrolled in Strong Start for Mothers and Newborns, a federal preterm birth prevention program. Methods Twenty-seven awardees with more than 200 sites in 30 states, the District of Columbia, and Puerto Rico enrolled approximately 46,000 women in Strong Start from 2013 to 2016. Participant data, including data on preterm birth and 17P, was collected for each woman. Intensive interviews (n = 211) conducted with Strong Start program staff and providers (n = 314) included questions about 17P provision. Results Of women whose data included a valid response regarding 17P initiation, 3919 had a prior preterm birth and current singleton pregnancy; 14.95% received 17P. Barriers to 17P administration include late entry to prenatal care, administrative burden of preauthorization, cost risks to providers, limits in scope of practice for non-physician providers, and social barriers among participants. Facilitators for provision include streamlined work flows and the option of home administration. Conclusions for Practice A universal insurance authorization process could mitigate many barriers to 17P use. Providers need continuing education regarding the effectiveness of 17P, and expanding scope of practice for non-physician prenatal care providers would increase access. Targeted program interventions can help to overcome social barriers Medicaid participants face in accessing care. Streamlined work processes and the option of home health services are two effective program-based facilitators for providing 17P to a Medicaid population.


Assuntos
Hidroxiprogesteronas/administração & dosagem , Medicaid/estatística & dados numéricos , Nascimento Prematuro/prevenção & controle , Cuidado Pré-Natal/métodos , Caproato de 17 alfa-Hidroxiprogesterona , Adulto , District of Columbia , Feminino , Disparidades em Assistência à Saúde , Humanos , Recém-Nascido , Mães , Gravidez , Porto Rico , Fatores Socioeconômicos , Estados Unidos
15.
Matern Child Nutr ; 14(2): e12550, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29098763

RESUMO

Suboptimal breastfeeding practices, early initiation of complementary feeding, and monotonous cereal-based diets have been implicated as contributors to continuing high rates of child undernutrition in sub-Saharan Africa. Nutrition-sensitive interventions, including agricultural programs that increase access to nutrient-rich vegetables, legumes, and animal-source foods, have the potential to achieve sustainable improvements in children's diets. In the quest to evaluate the efficacy of such programs in improving growth and development in the first 2 years of life, there is a role for mixed methods research to better understand existing infant and young child feeding practices. This analysis forms part of a longitudinal study assessing the impact of improvements to poultry health and crop production on diets and growth of 503 randomly selected children from eight rural communities in Manyoni District in central Tanzania. Using an explanatory sequential design, the quantitative phase of data collection was conducted between May 2014 and May 2016, comprising six monthly structured questionnaires, four monthly household-level documentation of chicken and egg consumption, and fortnightly records of children's breastfeeding status. The subsequent qualitative phase involved in-depth interviews with a subset of 39 mothers in October 2016. Breastfeeding was almost universal (96.8%) and of long duration (mean = 21.7 months, SD = 3.6), but early initiation of complementary feeding was also common (74.4%; mean = 4.0 months, SD = 1.8), overwhelmingly driven by maternal perceptions of insufficient milk supply (95.0%). Chicken and eggs were infrequently eaten, but close associations between maternal and child consumption patterns (p < .001) suggest the potential for strategies that increase household-level consumption to bring nutritional benefits to young children.


Assuntos
Fenômenos Fisiológicos da Nutrição Infantil/fisiologia , Dieta/métodos , Alimentos Infantis/estatística & dados numéricos , Fenômenos Fisiológicos da Nutrição do Lactente/fisiologia , Produtos Avícolas/estatística & dados numéricos , População Rural/estatística & dados numéricos , Pré-Escolar , Humanos , Lactente , Estudos Longitudinais , Masculino , Tanzânia
16.
Clin Sci (Lond) ; 131(21): 2643-2653, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28982725

RESUMO

Leucine modulates muscle protein synthesis (MPS), with potential to facilitate accrual/maintenance of muscle mass. Animal models suggest that leucine boluses shortly after meals may prolong MPS and delay onset of a "muscle-full" state. However, the effects of nutrient "top-ups" in humans, and particularly older adults where deficits exist, have not been explored. We determined the effects of a leucine top-up after essential amino acid (EAA) feeding on anabolic signaling, MPS, and muscle energy metabolism in older men. During 13C6-phenylalanine infusion, 16 men (∼70 years) consumed 15 g of EAA with (n=8, FED + LEU) or without (n=8, FED) 3 g of leucine top-up 90 min later. Repeated blood and muscle sampling permitted measurement of fasting and postprandial plasma EAA, insulin, anabolic signaling including mTOR complex 1 (mTORC1) substrates, cellular ATP and phosphorylocreatine, and MPS. Oral EAA achieved rapid insulinemia (12.5 iU·ml-1 25 min post-feed), essential aminoacidemia (3000 µM, 45-65 min post-feed), and activation of mTORC1 signaling. Leucine top-up prolonged plasma EAA (2800 µM, 135 min) and leucine availability (1050 µM, 135 min post-feed). Fasting FSRs of 0.046 and 0.056%·h-1 (FED and FED + LEU respectively) increased to 0.085 and 0.085%·h-1 90-180 min post-feed and returned to basal rates after 180 min in both groups. Phosphorylation of mTORC1 substrates returned to fasting levels 240 min post-feed in both groups. Feeding had limited effect on muscle high-energy phosphates, but did induce eukaryotic elongation factor 2 (eEF2) phosphorylation. We demonstrate the refractoriness of muscle to nutrient-led anabolic stimulation in the postprandial period; thus, leucine supplements should be taken outside of meals, or with meals containing suboptimal protein in terms of either amount or EAA composition.


Assuntos
Envelhecimento/metabolismo , Anabolizantes/administração & dosagem , Suplementos Nutricionais , Metabolismo Energético/efeitos dos fármacos , Leucina/administração & dosagem , Músculo Esquelético/efeitos dos fármacos , Período Pós-Prandial , Biossíntese de Proteínas/efeitos dos fármacos , Trifosfato de Adenosina/metabolismo , Fatores Etários , Idoso , Envelhecimento/sangue , Anabolizantes/sangue , Humanos , Insulina/sangue , Leucina/sangue , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina , Complexos Multiproteicos/metabolismo , Músculo Esquelético/metabolismo , Fosfocreatina/metabolismo , Fosforilação , Estudos Prospectivos , Fatores Sexuais , Serina-Treonina Quinases TOR/metabolismo , Fatores de Tempo
17.
Br J Nutr ; 116(10): 1709-1719, 2016 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-27821202

RESUMO

Animal-source foods (ASF) have the potential to enhance the nutritional adequacy of cereal-based diets in low- and middle-income countries, through the provision of high-quality protein and bioavailable micronutrients. The development of guidelines for including ASF in local diets requires an understanding of the nutrient content of available resources. This article reviews food composition tables (FCT) used in sub-Saharan Africa, examining the spectrum of ASF reported and exploring data sources for each reference. Compositional data are shown to be derived from a small number of existing data sets from analyses conducted largely in high-income nations, often many decades previously. There are limitations in using such values, which represent the products of intensively raised animals of commercial breeds, as a reference in resource-poor settings where indigenous breed livestock are commonly reared in low-input production systems, on mineral-deficient soils and not receiving nutritionally balanced feed. The FCT examined also revealed a lack of data on the full spectrum of ASF, including offal and wild foods, which correspond to local food preferences and represent valuable dietary resources in food-deficient settings. Using poultry products as an example, comparisons are made between compositional data from three high-income nations, and potential implications of differences in the published values for micronutrients of public health significance, including Fe, folate and vitamin A, are discussed. It is important that those working on nutritional interventions and on developing dietary recommendations for resource-poor settings understand the limitations of current food composition data and that opportunities to improve existing resources are more actively explored and supported.

18.
Phys Chem Chem Phys ; 18(18): 12476-85, 2016 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-27087259

RESUMO

Bulk-heterojunction (BHJ) molecular blends prepared from small molecules based on diketopyrrolopyrrole (DPP) and perylene-diimide (PDI) chromophores have been studied using optical absorption, cyclic voltammetry, photoluminescence quenching, X-ray diffraction, atomic force microscopy, and current-voltage measurements. The results provided useful insights into the use of DPP and PDI based molecules as donor-acceptor composites for organic photovoltaic (OPV) applications. Beside optoelectronic compatibility, the choice of active layer processing conditions is of key importance to improve the performance of BHJ solar cells. In this context, post-production treatments, viz. thermal and solvent vapour annealing, and the use of 1,8-diiodooctane as a solvent additive were employed to optimize the morphology of blend films. X-ray diffraction and atomic force microscopy indicated that the aforementioned processing strategies led to non-optimal composite morphologies with significantly large crystallites in comparison to exciton diffusion lengths. Although the open circuit voltage of the OPV devices was satisfactory (0.78 V), it was anticipated that the bulky domains hamper charge dissociation and transport, which resulted in low photovoltaic performance.

19.
Biochim Biophys Acta ; 1839(12): 1385-94, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24954181

RESUMO

Cells can adapt to their environment and develop distinct identities by rewiring their transcriptional networks to regulate the output of key biological pathways without concomitant mutations to the underlying genes. These alterations, called epigenetic changes, persist stably through mitotic or, in some instances, meiotic cell divisions. In eukaryotes, heritable changes to chromatin structure are a prominent, but not exclusive, mechanism by which epigenetic changes are mediated. These changes are initiated by sequence-specific events, which trigger a cascade of molecular interactions resulting in feedback mechanisms, alterations in chromatin structure, histone posttranslational modifications (PTMs), and ultimately establishment of distinct transcriptional states. In recent years, advances in next generation sequencing have led to the discovery of several novel classes of noncoding RNAs (ncRNAs). In addition to their well-established cytoplasmic roles in posttranscriptional regulation of gene expression, ncRNAs have emerged as key regulators of epigenetic changes via chromatin-dependent mechanisms in organisms ranging from yeast to man. They function by affecting chromatin structure, histone PTMs, and the recruitment of transcriptional activating or repressing complexes. Among histone PTMs, lysine methylation serves as the binding substrate for the recruitment of key protein complexes involved in the regulation of genome architecture, stability, and gene expression. In this review, we will outline the known mechanisms by which ncRNAs of different origins regulate histone methylation, and in doing so contribute to a variety of genome regulatory functions in eukaryotes.


Assuntos
Epigênese Genética , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/metabolismo , Processamento de Proteína Pós-Traducional/genética , RNA não Traduzido/fisiologia , Animais , Cromatina/genética , Cromatina/metabolismo , Histona Metiltransferases , Humanos , Metilação
20.
Nat Mater ; 13(8): 822-8, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24907929

RESUMO

Colloidal quantum dots (CQDs) offer promise in flexible electronics, light sensing and energy conversion. These applications rely on rectifying junctions that require the creation of high-quality CQD solids that are controllably n-type (electron-rich) or p-type (hole-rich). Unfortunately, n-type semiconductors made using soft matter are notoriously prone to oxidation within minutes of air exposure. Here we report high-performance, air-stable n-type CQD solids. Using density functional theory we identify inorganic passivants that bind strongly to the CQD surface and repel oxidative attack. A materials processing strategy that wards off strong protic attack by polar solvents enabled the synthesis of an air-stable n-type PbS CQD solid. This material was used to build an air-processed inverted quantum junction device, which shows the highest current density from any CQD solar cell and a solar power conversion efficiency as high as 8%. We also feature the n-type CQD solid in the rapid, sensitive, and specific detection of atmospheric NO2. This work paves the way for new families of electronic devices that leverage air-stable quantum-tuned materials.

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