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1.
Nature ; 601(7892): 201-204, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35022591

RESUMO

The final fate of massive stars, and the nature of the compact remnants they leave behind (black holes and neutron stars), are open questions in astrophysics. Many massive stars are stripped of their outer hydrogen envelopes as they evolve. Such Wolf-Rayet stars1 emit strong and rapidly expanding winds with speeds greater than 1,000 kilometres per second. A fraction of this population is also helium-depleted, with spectra dominated by highly ionized emission lines of carbon and oxygen (types WC/WO). Evidence indicates that the most commonly observed supernova explosions that lack hydrogen and helium (types Ib/Ic) cannot result from massive WC/WO stars2,3, leading some to suggest that most such stars collapse directly into black holes without a visible supernova explosion4. Here we report observations of SN 2019hgp, beginning about a day after the explosion. Its short rise time and rapid decline place it among an emerging population of rapidly evolving transients5-8. Spectroscopy reveals a rich set of emission lines indicating that the explosion occurred within a nebula composed of carbon, oxygen and neon. Narrow absorption features show that this material is expanding at high velocities (greater than 1,500 kilometres per second), requiring a compact progenitor. Our observations are consistent with an explosion of a massive WC/WO star, and suggest that massive Wolf-Rayet stars may be the progenitors of some rapidly evolving transients.

2.
Public Health Nutr ; 24(5): 924-934, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-32838832

RESUMO

OBJECTIVE: To elucidate mechanisms across family function, home environment and eating behaviours within sociocultural context among Hispanic youth. DESIGN: Two models tested via path analysis (youth fruit and vegetable (FV) consumption; empty energy consumption) using data from the Study of Latino Youth (2011-2013). SETTING: Chicago, IL; Miami, FL; Bronx, NY; San Diego, CA. PARTICIPANTS: Youth (8-16-year-olds), n 1466. RESULTS: Youth ate 2·4 servings of FV per d and received 27 % of total energy from empty energies. Perceiving higher acculturative stress was indirectly associated with lower FV consumption via a pathway of low family function and family support for FV (ß = -0·013, P < 0·001) and via lower family closeness and family support (ß = -0·004, P = 0·004). Being >12-year-olds was indirectly associated with lower FV consumption via lower family closeness and family support (ß = -0·006, P < 0·001). Household food security was indirectly associated with greater FV consumption via family closeness and family support (ß = 0·005, P = 0·003). In contrast, perceiving higher acculturative stress was indirectly associated with higher empty energy consumption (via family closeness and family support: ß = 0·003, P = 0·028 and via low family function and low family support: ß = 0·008, P = 0·05). Being older was associated with higher consumption of empty energies via family closeness (related to family support: ß = 0·04, P = 0·016; parenting strategies for eating: ß = 0·002, P = 0·049). CONCLUSIONS: Findings suggest pathways of influence across demographic and sociocultural context, family dynamics and home environment. The directionality of these associations needs confirmation using longitudinal data.


Assuntos
Saúde da Criança , Hispânico ou Latino , Aculturação , Adolescente , Criança , Comportamento Alimentar , Humanos , Poder Familiar , Verduras
3.
Public Health ; 199: 32-33, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34534887

RESUMO

OBJECTIVES: We aimed to assess the evidence on the usefulness of postvaccination testing of COVID-19 antibodies. STUDY DESIGN: We used a descriptive analytical approach. METHODS: We synthesized insights of studies on the immunological responses to SARS-CoV-2 after natural infection or vaccination and recommendations by regulatory institutions, such as the Food and Drug Administration and the Centers for Disease Control and Prevention in the United States. RESULTS: Based on the multiple humoral and cellular responses elicited by either the virus or the vaccines, the high variability of antibodies in blood, and the lack of correlation between the presence of antibodies and active cellular immunity against SARS-CoV-2, there has been explicit advice against assessing immunological status postvaccination. CONCLUSIONS: Postvaccination antibody testing is not warranted to assess immunity status for COVID-19. Patients may misinterpret results, leading to the spread of misinformation regarding vaccine efficacy or the need to continue self-protection or the protection of others. Therefore, public health authorities should actively challenge the promotion and commercialization of this type of tests.


Assuntos
COVID-19 , Teste para COVID-19 , Humanos , SARS-CoV-2 , Estados Unidos , Vacinação
4.
BMC Plant Biol ; 20(1): 322, 2020 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-32641108

RESUMO

BACKGROUND: Sclerotinia sclerotiorum is a necrotrophic fungus that causes Sclerotinia head rot (SHR) in sunflower, with epidemics leading to severe yield losses. In this work, we present an association mapping (AM) approach to investigate the genetic basis of natural resistance to SHR in cultivated sunflower, the fourth most widely grown oilseed crop in the world. RESULTS: Our association mapping population (AMP), which comprises 135 inbred breeding lines (ILs), was genotyped using 27 candidate genes, a panel of 9 Simple Sequence Repeat (SSR) markers previously associated with SHR resistance via bi-parental mapping, and a set of 384 SNPs located in genes with molecular functions related to stress responses. Moreover, given the complexity of the trait, we evaluated four disease descriptors (i.e, disease incidence, disease severity, area under the disease progress curve for disease incidence, and incubation period). As a result, this work constitutes the most exhaustive AM study of disease resistance in sunflower performed to date. Mixed linear models accounting for population structure and kinship relatedness were used for the statistical analysis of phenotype-genotype associations, allowing the identification of 13 markers associated with disease reduction. The number of favourable alleles was negatively correlated to disease incidence, disease severity and area under the disease progress curve for disease incidence, whereas it was positevily correlated to the incubation period. CONCLUSIONS: Four of the markers identified here as associated with SHR resistance (HA1848, HaCOI_1, G33 and G34) validate previous research, while other four novel markers (SNP117, SNP136, SNP44, SNP128) were consistently associated with SHR resistance, emerging as promising candidates for marker-assisted breeding. From the germplasm point of view, the five ILs carrying the largest combination of resistance alleles provide a valuable resource for sunflower breeding programs worldwide.


Assuntos
Ascomicetos/fisiologia , Resistência à Doença/genética , Helianthus/genética , Doenças das Plantas/imunologia , Alelos , Mapeamento Cromossômico , Estudos de Associação Genética , Genótipo , Helianthus/fisiologia , Repetições de Microssatélites/genética , Fenótipo , Melhoramento Vegetal , Doenças das Plantas/microbiologia , Polimorfismo de Nucleotídeo Único/genética
5.
Dis Aquat Organ ; 141: 127-138, 2020 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-32969345

RESUMO

Caligus rogercresseyi is the dominant sea louse parasite affecting the salmon and trout industry in southern Chile. This parasite has a wide range of native and endemic fish hosts. The Patagonian blenny Eleginops maclovinus, which is parasitized mostly by the caligid species Lepeophtheirus spp. and C. rogercresseyi, is presumably responsible for the transmission of C. rogercresseyi to salmonids. The aim of this study was to characterize the transmission of parasites between different fish species and parasite cohort development under laboratory conditions. Parasite abundances and intensities were quantified. Transmission of parasites from Patagonian blenny to Atlantic salmon Salmo salar was lower (~9%, mainly corresponding to C. rogercresseyi) than from salmon to Patagonian blenny (14.7-26.9%, where only C. rogercresseyi were observed). This suggests that the transmission of C. rogercresseyi from salmon individuals is higher than the transmission from a native fish. Parasite cohorts developed successfully on both fish species, but apparently under different developmental rates. Water temperature, oxygen, and juvenile abundances were the variables that better explained cohort development success and variation in C. rogercresseyi adult abundances over time.


Assuntos
Copépodes , Doenças dos Peixes , Salmo salar , Salmonidae , Animais , Chile/epidemiologia , Doenças dos Peixes/epidemiologia , Salmão
6.
Colorectal Dis ; 21(1): 110-118, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30047611

RESUMO

AIM: Surgical site infection in colorectal surgery is associated with significant healthcare costs, which may be reduced by using a closed-incision negative-pressure therapy device. The aim of this study was to assess the impact of closed-incision negative-pressure therapy on the incidence of surgical site infection. METHOD: In this retrospective cohort study we evaluated all patients who had undergone high-risk open colorectal surgery at a single tertiary care centre from 2012 to 2016. We compared the incidence of surgical site infection between those receiving standard postoperative wound care between 2012 and 2014 and those receiving closed-incision negative-pressure therapy via a customizable device (Prevena Incision Management System, KCI, an Acelity company, San Antonio, Texas, USA) between 2014 and 2016. A validated surgical site infection risk score was used to create a 1:1 matched cohort subset. RESULTS: Negative pressure therapy was used in 77 patients and compared with 238 controls. Negative pressure patients were more likely to have a stoma (92% vs 48%, P < 0.01) and to be smokers (33% vs 15%, P < 0.01). Surgical site infection was higher in control patients (15%, n = 35/238) compared with negative pressure patients (7%, n = 5/77) (P = 0.05). On regression analysis, negative pressure therapy was associated with decreased surgical site infection (OR 0.27; 95% CI 0.09-0.78). These differences persisted in the matched analysis. CONCLUSION: Negative pressure therapy was associated with decreased surgical site infection. Negative pressure therapy offers significant potential for quality improvement.


Assuntos
Procedimentos Cirúrgicos do Sistema Digestório/métodos , Tratamento de Ferimentos com Pressão Negativa/métodos , Infecção da Ferida Cirúrgica/prevenção & controle , Ferida Cirúrgica/terapia , Adulto , Idoso , Estudos de Casos e Controles , Colectomia/métodos , Feminino , Humanos , Intestino Delgado/cirurgia , Laparotomia , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Protectomia/métodos , Estudos Retrospectivos , Risco , Estomas Cirúrgicos
7.
BMC Vet Res ; 15(1): 259, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31340824

RESUMO

BACKGROUND: Chlamydia abortus, an obligate intracellular pathogen with an affinity for placenta, causes reproductive failure. In non-pregnant animals, an initial latent infection is established until the next gestation, when the microorganism is reactivated, causing abortion. The precise mechanisms that trigger the awakening of C. abortus are still unknown. Sexual hormones such as estradiol and progesterone have been shown to affect the outcome of infection in other species of the family Chlamydiaceae, while estrogens increase chlamydial infection, progesterone has the opposite effect. To try to establish whether there is a relationship between these events and the latency/ reactivation of C. abortus in the reproductive tract of small ruminants, ovine endometrial (LE) and trophoblastic (AH-1) cells were treated with estradiol or progesterone prior to their infection with C. abortus. The results are compared with those obtained for treatment with penicillin prior to infection, which is a well-established model for studying persistent infection in other chlamydial species. Cells were examined by transmission electron microscopy, and an mRNA expression analysis of 16 genes related to the chlamydial developmental cycle was made. RESULTS: The changes observed in this study by the action of sex hormones seem to depend on the type of cell where the infection develops. In addition, while the changes are morphologically similar to those induced by treatment with penicillin, the patterns of gene expression are different. Gene expression patterns therefore, seem to depend on the persistence induced models of C. abortus used. Hormone treatments induced aberrant forms in infected endometrial cells but did not affect the chlamydial morphology in trophoblast cells. At the genetic level, hormones did not induce significant changes in the expression of the studied genes. CONCLUSIONS: The results suggest that penicillin induces a state of persistence in in vitro cultured C. abortus with characteristic morphological features and gene transcriptional patterns. However, the influence of hormones on the C. abortus developmental cycle is mediated by changes in the host cell environment. Furthermore, a persistent state in C. abortus cannot be characterised by a single profile of gene expression pattern, but may change depending on the model used to induce persistence.


Assuntos
Chlamydia/efeitos dos fármacos , Estradiol/farmacologia , Progesterona/farmacologia , Animais , Linhagem Celular , Chlamydia/crescimento & desenvolvimento , Chlamydia/ultraestrutura , Infecções por Chlamydia/veterinária , Feminino , Expressão Gênica , Microscopia Eletrônica de Transmissão/veterinária , Penicilinas/administração & dosagem , RNA Mensageiro , Ovinos
8.
J Chem Phys ; 150(12): 124301, 2019 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-30927877

RESUMO

The efficiency of the intramolecular energy transfer in light harvesting dendrimers is determined by their well-defined architecture with high degree of order. After photoexcitation, through-space and through-bond energy transfer mechanisms can take place, involving vectorial exciton migration among different chromophores within dendrimer highly branched structures. Their inherent intramolecular energy gradient depends on how the multiple chromophoric units have been assembled, subject to their inter-connects, spatial distances, and orientations. Herein, we compare the photoinduced nonadiabatic molecular dynamics simulations performed on a set of different combinations of a chain of linked dendrimer building blocks composed of two-, three-, and four-ring linear polyphenylene chromophoric units. The calculations are performed with the recently developed ab initio multiple cloning-time dependent diabatic basis implementation of the Multiconfigurational Ehrenfest (MCE) approach. Despite differences in short time relaxation pathways and different initial exciton localization, at longer time scales, electronic relaxation rates and exciton final redistributions are very similar for all combinations. Unlike the systems composed of two building blocks, considered previously, for the larger 3 block systems here we observe that bifurcation of the wave function accounted by cloning is important. In all the systems considered in this work, at the time scale of few hundreds of femtoseconds, cloning enhances the electronic energy relaxation by ∼13% compared to that of the MCE method without cloning. Thus, accurate description of quantum effects is essential for understanding of the energy exchange in dendrimers both at short and long time scales.

9.
Microsc Microanal ; 25(4): 989-997, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31272515

RESUMO

Here, different tissue surfaces of tomato root were characterized employing atomic force microscopy on day 7 and day 21 of growth through Young's modulus and plasticity index. These parameters provide quantitative information regarding the mechanical behavior of the tomato root under fresh conditions in different locations of the cross-section of root [cell surface of the epidermis, parenchyma (Pa), and vascular bundles (Vb)]. The results show that the mechanical parameters depend on the indented region, tissue type, and growth time. Thereby, the stiffness increases in the cell surface of epidermal tissue with increasing growth time (from 9.19 ± 0.68 to 13.90 ± 1.68 MPa) and the cell surface of Pa tissue displays the opposite behavior (from 1.74 ± 0.49 to 0.48 ± 0.55); the stiffness of cell surfaces of Vb tissue changes from 10.60 ± 0.58 to 6.37 ± 0.53 MPa, all cases showed a statistical difference (p < 0.05). Viscoelastic behavior dominates the mechanical forces in the tomato root. The current study is a contribution to a better understanding of the cell mechanics behavior of different tomato root tissues during growth.


Assuntos
Fenômenos Biomecânicos , Microscopia de Força Atômica/métodos , Raízes de Plantas/crescimento & desenvolvimento , Solanum lycopersicum/crescimento & desenvolvimento , Elasticidade , Fatores de Tempo
10.
Phys Chem Chem Phys ; 20(47): 29648-29660, 2018 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-30465570

RESUMO

Photoexcitation of multichromophoric light harvesting molecules induces a number of intramolecular electronic energy relaxation and redistribution pathways that can ultimately lead to ultrafast exciton self-trapping on a single chromophore unit. We investigate the photoinduced processes that take place on a phenylene-ethynylene dendrimer, consisting of nine equivalent linear chromophore units or branches. meta-Substituted links between branches break the conjugation giving rise to weak couplings between them and to localized excitations. Our nonadiabatic excited-state molecular dynamics simulations reveal that the ultrafast internal conversion process to the lowest excited state is accompanied by an inner → outer inter-branch migration of the exciton due to the entropic bias associated with energetically equivalent conjugated segments. The electronic energy redistribution among chromophore units occurs through several possible pathways in which through-bond transport and through-space exciton hopping mechanisms can be distinguished. Besides, triple bond excitations coincide with the localization of the electronic transition densities, suggesting that the intramolecular energy redistribution is a concerted electronic and vibrational energy transfer process.

11.
Rev Sci Tech ; 37(3): 907-924, 2018 Dec.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-30964470

RESUMO

Toxoplasmosis is one of the most widespread zoonoses in the world, due to the existence of a wide variety of Toxoplasma gondii hosts, which include several domestic animal species. In Cuba, there is sustained production of the Bubalus species, which is highly adaptable and disease resistant, although it has been identified as a reservoir for a range of aetiological agents. Several countries have reported buffaloes as the intermediate host of T. gondii, noting the need to carry out epidemiological studies and confirm the possible presence of this parasitic infection in the Bubalus species. The current study was conducted to validate an inhibition enzyme-linked immunosorbent assay (i/ELISA) system for the diagnosis of T. gondii infection in buffaloes (Bubalus bubalis). This involved evaluating its performance in relation to that of a latex agglutination test. With buffalo sera, the i/ELISA assay showed a sensitivity of 100%, a specificity of 99.5%,and a concordance of 0.99 (considered very good) with respect to the reference diagnostic method. The conclusion is that i/ELISA performs extremely well as a serological test for the diagnosis of T. gondii in buffaloes.


La toxoplasmose est l'une des zoonoses les plus répandues dans le monde, ce qui s'explique par le très large spectre d'hôtes de Toxoplasma gondii, dont plusieurs espèces d'animaux domestiques. À Cuba, les buffles font l'objet d'un élevage durable et présentent de bonnes aptitudes d'adaptation et de résistance aux maladies, bien que cette espèce joue un rôle avéré de réservoir pour un certain nombre d'agents pathogènes. Des rapports émanant de plusieurs pays ont fait état du rôle joué par les buffles en tant qu'hôtes intermédiaires de T. gondii, d'où la nécessité d'effectuer des études épidémiologiques afin de confirmer la présence éventuelle de cette parasitose chez cette espèce. Les auteurs présentent des résultats d'une étude de validation d'une méthode immuno-enzymatique d'inhibition des anticorps pour le diagnostic de T. gondii chez le buffle (Bubalusbubalis). Pour ce faire, les performances de cette méthode ont été évaluées par rapport à celles du test d'agglutination au latex. La comparaison à partir de sérums de buffles a montré que la sensibilité de l'épreuve immuno-enzymatique était de 100 % et sa spécificité de 99,5%, avec une concordance par rapport à la méthode de référence de 0,99, ce qui est considéré un très bon résultat. Cette étude démontre l'aptitude de l'ELISA d'inhibition pour le diagnostic sérologique de T. gondii chez le buffle et conclut à son excellente performance diagnostique.


La toxoplasmosis es una de las zoonosis más difundidas en el mundo debido a que existe una amplia variedad de hospedadores de Toxoplasma gondii, entre los que se encuentran varias de las especies de animales domésticos. En Cuba, la especie bufalina se produce de manera sostenida con buena adaptabilidad y resistencia a las enfermedades, aunque se ha identificado como reservorio de diversos agentes etiológicos. En varios países se ha informado que los búfalos son hospedadores intermediarios de T. gondii y se ha indicado la necesidad derealizar estudios epidemiológicos y de comprobar la posible presencia de dicha parasitosis en esta especie. Este trabajo se realizó para validar un sistema inmunoenzimático de inhibición de un anticuerpo (ELISA/i) para el diagnósticode infección por T. gondii en búfalos (Bubalus bubalis). Para ello, se evaluó su rendimiento respecto a una prueba de aglutinación por látex. Frente a sueros de búfalo, el sistema inmunoenzimático demostró tener una sensibilidad del 100%, una especificidad del 99,5% y una concordancia de 0,99, considerada muy buena, respecto al método de diagnóstico de referencia. Se concluye que el ELISA/i permite el diagnóstico serológico de T. gondii en búfalos con un excelente rendimiento diagnóstico.


Assuntos
Toxoplasmose Animal , Animais , Anticorpos Antiprotozoários , Búfalos , Ensaio de Imunoadsorção Enzimática
12.
Bull Environ Contam Toxicol ; 101(4): 423-427, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30132017

RESUMO

Limited studies indicate that mussels are generally insensitive to organic chemicals; however, these studies were conducted in acute or short-term exposures, and little is known about the chronic sensitivity of mussels to organic chemicals. We evaluated the chronic (28 days) toxicity of 4-nonylphenol (4-NP) to two commonly tested species of mussels: fatmucket (Lampsilis siliquoidea) and rainbow mussel (Villosa iris). By the end of the 28 days chronic exposures, mean survival was ≥93% in all treatments, but the mean dry weight and biomass of mussels at the highest exposure concentrations were significantly reduced relative to the control. The 20% effect concentrations were similar between the two species. When compared to all other tested species, fatmucket and rainbow mussels are among the top four most sensitive species to 4-NP. However, U.S. Environmental Protection Agency chronic water quality criterion of 6.6 µg 4-NP/L should protect the two mussel species.


Assuntos
Fenóis/toxicidade , Unionidae/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais
13.
Plant Dis ; 101(11): 1941-1948, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30677319

RESUMO

Sclerotinia head rot (SHR) is one of the most serious constraints to sunflower (Helianthus annuus L. var. macrocarpus) production worldwide. Here, we evaluated the response to SHR in a sunflower inbred panel from a large INTA germplasm collection, consisting of 137 inbred lines (ILs). Field trials were performed over five consecutive seasons using a twice-replicated randomized complete-block design. Disease incidence, disease severity, incubation period, and area under disease progress curve for disease incidence and severity were determined after controlled inoculation with the pathogen. Statistical analysis using mixed-effect models detected significant differences among ILs for all variables (P < 0.001). In addition, principal component analysis (PCA) and distance-based methods were used to classify the ILs according to their response to SHR, with ILs ALB2/5261 and 5383 emerging as the most resistant. Broad-sense heritability estimates ranged from 20.64% for disease severity to 10.58% for incubation period. The ample phenotypic variability of our collection, along with the moderate heritability estimates, highlight the importance of molecular breeding approaches to gain new insights into the genetic basis of sunflower resistance to SHR. The exhaustive phenotypic characterization presented here provides a reliable set of variables to comprehensively evaluate the disease and identifies two new sources of resistance to SHR.


Assuntos
Ascomicetos , Helianthus , Melhoramento Vegetal , Doenças das Plantas , Resistência à Doença/genética , Helianthus/microbiologia , Humanos , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle
16.
Clin Genet ; 89(4): 461-465, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26346709

RESUMO

Over 5% of the world's population has varying degrees of hearing loss. Mutations in GJB2 are the most common cause of autosomal recessive non-syndromic hearing loss (ARNHL) in many populations. The frequency and type of mutations are influenced by ethnicity. Guatemala is a multi-ethnic country with four major populations: Maya, Ladino, Xinca, and Garifuna. To determine the mutation profile of GJB2 in a ARNHL population from Guatemala, we sequenced both exons of GJB2 in 133 unrelated families. A total of six pathogenic variants were detected. The most frequent pathogenic variant is c.131G>A (p.Trp44*) detected in 21 of 266 alleles. We show that c.131G>A is associated with a conserved haplotype in Guatemala suggesting a single founder. The majority of Mayan population lives in the west region of the country from where all c.131G>A carriers originated. Further analysis of genome-wide variation of individuals carrying the c.131G>A mutation compared with those of Native American, European, and African populations shows a close match with the Mayan population.

17.
Phys Chem Chem Phys ; 18(36): 25080-25089, 2016 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-27711661

RESUMO

Dendrimers are arrays of coupled chromophores, where the energy of each unit depends on its structure and conformation. The light harvesting and energy funneling properties are strongly dependent on their highly branched conjugated architecture. Herein, the photoexcitation and subsequent ultrafast electronic energy relaxation and redistribution of a first generation dendrimer (1) are analyzed combining theoretical and experimental studies. Dendrimer 1 consists of three linear phenylene-ethynylene (PE) units, or branches, attached in the meta position to a central group opening up the possibility of inter-branch energy transfer. Excited state dynamics are explored using both time-resolved spectroscopy and non-adiabatic excited state molecular dynamics simulations. Our results indicate a subpicosecond loss of anisotropy due to an initial excitation into several states with different spatial localizations, followed by exciton self-trapping on different units. This exciton hops between branches. The absence of an energy gradient leads to an ultrafast energy redistribution among isoenergetic chromophore units. At long times we observe similar probabilities for each branch to retain significant contributions of the transition density of the lowest electronic excited-state. The observed unpolarized emission is attributed to the contraction of the electronic wavefunction onto a single branch with frequent interbranch hops, and not to its delocalization over the whole dendrimer.

18.
Public Health Nutr ; 19(18): 3256-3264, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27339078

RESUMO

OBJECTIVE: Measurement error in self-reported total sugars intake may obscure associations between sugars consumption and health outcomes, and the sum of 24 h urinary sucrose and fructose may serve as a predictive biomarker of total sugars intake. DESIGN: The Study of Latinos: Nutrition & Physical Activity Assessment Study (SOLNAS) was an ancillary study to the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) cohort. Doubly labelled water and 24 h urinary sucrose and fructose were used as biomarkers of energy and sugars intake, respectively. Participants' diets were assessed by up to three 24 h recalls (88 % had two or more recalls). Procedures were repeated approximately 6 months after the initial visit among a subset of ninety-six participants. SETTING: Four centres (Bronx, NY; Chicago, IL; Miami, FL; San Diego, CA) across the USA. SUBJECTS: Men and women (n 477) aged 18-74 years. RESULTS: The geometric mean of total sugars was 167·5 (95 % CI 154·4, 181·7) g/d for the biomarker-predicted and 90·6 (95 % CI 87·6, 93·6) g/d for the self-reported total sugars intake. Self-reported total sugars intake was not correlated with biomarker-predicted sugars intake (r=-0·06, P=0·20, n 450). Among the reliability sample (n 90), the reproducibility coefficient was 0·59 for biomarker-predicted and 0·20 for self-reported total sugars intake. CONCLUSIONS: Possible explanations for the lack of association between biomarker-predicted and self-reported sugars intake include measurement error in self-reported diet, high intra-individual variability in sugars intake, and/or urinary sucrose and fructose may not be a suitable proxy for total sugars intake in this study population.


Assuntos
Inquéritos sobre Dietas , Sacarose Alimentar/administração & dosagem , Hispânico ou Latino , Açúcares/administração & dosagem , Adolescente , Adulto , Idoso , Biomarcadores/urina , Sacarose Alimentar/urina , Ingestão de Energia , Feminino , Frutose/urina , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Autorrelato , Estados Unidos , Adulto Jovem
19.
Med Oral Patol Oral Cir Bucal ; 21(3): e385-91, 2016 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-26946205

RESUMO

BACKGROUND: The existing information on oral rehabilitations with dental implants in VIH-positive patients is scarce and of poor quality. Moreover, no long-term follow-up studies are available. Hence, the aims of this study were to describe the long-term survival and success rates of dental implants in a group of HIV-positive patients and to identify the most common postoperative complications, including peri-implant diseases. MATERIAL AND METHODS: A retrospective case series of HIV-positive subjects treated with dental implants at the School of Dentistry of the University of Barcelona (Spain) was studied. Several clinical parameters were registered, including CD4 cell count, viral load and surgical complications. Additionally, the patients were assessed for implant survival and success rates and for the prevalence of peri-implant diseases. A descriptive statistical analysis of the data was performed. RESULTS: Nine participants (57 implants) were included. The patients' median age was 42 years (IQR=13.5 years). The implant survival and success rates were 98.3% and 68.4%, respectively, with a mean follow-up of 77.5 months (SD=16.1 months). The patient-based prevalence of peri-implant mucositis and peri-implantitis were 22.2% and 44.4% respectively at the last appointment. Patients that attended regular periodontal maintenance visits had significantly less mean bone loss than non-compliant patients (1.3 mm and 3.9 mm respectively). CONCLUSIONS: Oral rehabilitation with dental implants in HIV-positive patients seems to provide satisfactory results. In order to reduce the considerably high prevalence of peri-implant diseases, strict maintenance programmes must be implemented.


Assuntos
Implantes Dentários , Falha de Restauração Dentária , Infecções por HIV , Perda do Osso Alveolar , Seguimentos , Humanos , Peri-Implantite , Estudos Retrospectivos , Espanha , Resultado do Tratamento
20.
Med Intensiva ; 40(3): 139-44, 2016 Apr.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-26725105

RESUMO

OBJECTIVES: Due to the increase in isolation of Candida spp. in critically ill patients, and the high mortality and economic costs which this infection entails, a study was made of the risk factors associated to candidemia in critically ill patients from 7 intensive care units in Colombia. MATERIALS AND METHODS: A multicenter matched case-control study was conducted in 7 intensive care units of 3 university hospitals. Data on overall length of hospital stay (including both general wards and the intensive care unit) were recorded. RESULTS: A total of 243 subjects (81 cases and 162 controls) between January 2008 and December 2012 were included. In order of frequency, C. albicans, C. tropicalis and C. parapsilosis were isolated. The main identified risk factors were: overall length of hospital stay>25 days (OR 5.33, 95% CI 2.6-10.9), use of meropenem (OR 3.75, 95% CI 1.86-7.5), abdominal surgery (OR 2.9, 95% CI 1.39-6.06) and hemodialysis (OR 3.35, 95% CI 1.5-7.7). No differences in mortality between patients with candidemia and controls were found (39.5 vs. 36.5%, respectively, P=.66) were found. CONCLUSIONS: In Colombia, a long hospital stay, abdominal surgery, the use of meropenem and hemodialysis were identified as risk factors for candidemia.


Assuntos
Candidemia/etiologia , Candidíase/etiologia , Estado Terminal , Antifúngicos/uso terapêutico , Candidíase/tratamento farmacológico , Estudos de Casos e Controles , Colômbia , Infecção Hospitalar , Humanos , Incidência , Tempo de Internação , Fatores de Risco
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