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1.
Nature ; 603(7899): 52-57, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35236977

RESUMO

All disc-accreting astrophysical objects produce powerful disc winds. In compact binaries containing neutron stars or black holes, accretion often takes place during violent outbursts. The main disc wind signatures during these eruptions are blue-shifted X-ray absorption lines, which are preferentially seen in disc-dominated 'soft states'1,2. By contrast, optical wind-formed lines have recently been detected in 'hard states', when a hot corona dominates the luminosity3. The relationship between these signatures is unknown, and no erupting system has as yet revealed wind-formed lines between the X-ray and optical bands, despite the many strong resonance transitions in this ultraviolet (UV) region4. Here we report that the transient neutron star binary Swift J1858.6-0814 exhibits wind-formed, blue-shifted absorption lines associated with C IV, N V and He II in time-resolved UV spectroscopy during a luminous hard state, which we interpret as a warm, moderately ionized outflow component in this state. Simultaneously observed optical lines also display transient blue-shifted absorption. Decomposing the UV data into constant and variable components, the blue-shifted absorption is associated with the former. This implies that the outflow is not associated with the luminous flares in the data. The joint presence of UV and optical wind features reveals a multi-phase and/or spatially stratified evaporative outflow from the outer disc5. This type of persistent mass loss across all accretion states has been predicted by radiation-hydrodynamic simulations6 and helps to explain the shorter-than-expected duration of outbursts7.

2.
Biol Lett ; 20(6): 20240082, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38889773

RESUMO

Floral longevity, the length of time a flower remains open and functional, is a phylogenetically conserved trait that balances floral costs against the rate at which flowers are pollinated. Floral symmetry has long been considered a key trait in floral evolution. Although zygomorphic (bilaterally symmetric) flowers typically receive fewer floral visitors than actinomorphic (radially symmetric) flowers, it is yet to be determined whether this could be associated with longer floral longevity. Using newly collected field data combined with data from the literature on 1452 species in 168 families, we assess whether floral longevity covaries with floral symmetry in a phylogenetic framework. We find that zygomorphic flowers last on average 1.1 days longer than actinomorphic flowers, a 26.5% increase in longevity, with considerable variation across both groups. Our results provide a basis to discuss the ecological and evolutionary costs of zygomorphy for plants. Despite these costs, zygomorphy has evolved numerous times throughout angiosperm history, and we discuss which rewards may outweigh the costs of slower pollination in zygomorphic flowers.


Assuntos
Evolução Biológica , Flores , Magnoliopsida , Filogenia , Polinização , Flores/anatomia & histologia , Flores/fisiologia , Magnoliopsida/fisiologia , Magnoliopsida/anatomia & histologia
3.
J Dairy Sci ; 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-39004125

RESUMO

The adulteration of milk presents significant challenges in the food industry, promoting the need for efficient detection methods. This study introduces a potentiometric electronic tongue for rapid and accurate milk adulteration detection. Utilizing polymeric membranes integrated with various additives, the electronic tongue distinguishes between different milk types and detects common adulterants. Experimental results demonstrate its effectiveness in discriminating raw, pasteurized, and medicated cow milk, as well as goat milk. Moreover, it successfully identifies adulterants like water and bovine milk in goat milk samples. Chemometric analyses, including Principal Component Analysis and Partial Least Squares regression, correlate sensor responses with traditional milk parameters such as fat, protein, and lactose content with up to a 0.97 R2 on the validation step. Strong correlations validate the electronic tongue's potential for rapid milk quality assessment. This innovative approach offers a cost-effective, reliable solution for detecting milk adulteration in contrast with current techniques that require numerous, time consuming experiments.

4.
Scand J Rheumatol ; 52(3): 268-275, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-35343366

RESUMO

OBJECTIVE: To investigate the relationship between pain extent, as a clinical sign of central sensitization, and clinical, psychological, and pressure sensitivity in women with fibromyalgia syndrome (FMS). METHOD: In this study, 126 females with FMS completed demographic (age, gender, body mass index, height, weight), clinical (pain history, and pain intensity at rest and during daily living activities), psychological (depression and anxiety levels), and neurophysiological [pressure pain threshold (PPT)] assessments. The Central Sensitization Inventory (CSI) was also used to collect self-reported symptoms of sensitization. Pain extent and frequency maps were obtained from pain drawings using customized software. After conducting a multivariable correlation analysis to determine the relationships between variables, a stepwise linear regression model analysis was performed to identify variables associated with pain extent. RESULTS: Pain extent was positively associated with age (r = 0.17), years with pain (r = 0.27), pain during daily life activities (r = 0.27), and CSI (r = 0.42) (all p < 0.05). The stepwise regression analysis revealed that 27.8% of the pain extent was explained by CSI, age, and years with pain. CONCLUSIONS: This study found that larger pain extent was associated with self-reported outcomes, i.e. CSI, but not neurophysiological outcomes, i.e. PPTs, of sensitization in women with FMS. Older age and a longer history with pain symptoms were also associated with larger pain extent.


Assuntos
Fibromialgia , Humanos , Feminino , Fibromialgia/diagnóstico , Fibromialgia/psicologia , Limiar da Dor/fisiologia , Sensibilização do Sistema Nervoso Central , Medição da Dor , Autorrelato
5.
BMC Cardiovasc Disord ; 23(1): 13, 2023 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-36635626

RESUMO

BACKGROUND: Right ventricular (RV) dysfunction in patients with non-ischemic dilated cardiomyopathy (NICM) is associated with cardiovascular events. To analyze the feasibility of assessing RV myocardial deformation by feature tracking (FT)-cardiac magnetic resonance (CMR), and its usefulness as a prognostic marker. METHODS: Retrospective study of NICM patients undergoing CMR. Longitudinal FT-RV free wall (LFT-RVFW) and fractional area change (FAC) were obtained. Correlation with standard RV parameters was studied. An association with combined event (heart failure (HF), ICD implantation or cardiovascular death) was assessed using a logistic regression model. RESULTS: 98 patients (64 ± 13 years) were included. Left ventricular (LV) systolic function (LVEF 29.5 ± 9.6%, 47% with LVEF ≥ 30%) and RV (RVEF 52.2 ± 14.6%, 72% with RVEF ≥ 45%). Follow-up of 38 ± 17 months, 26.5% presented at least one admission for HF. An excellent correlation of LFT-RVFW (r = 0.82) and FAC (r = 0.83) with RVEF was evident. No association of RV-FT parameters with prognosis entire study population was found. However, in patients with LVEF ≥ 30%, admissions for HF were associated with lower LFT-RVFW (-21.6 ± 6.6% vs -31.3 ± 10%; p = 0.006) and FAC (36.6 ± 9.6% vs 50.5 ± 13.4%; p < 0.001) values. Similar differences were observed when only patients with RVEF ≥ 45% were considered. An LFT-RVFW cut-off point of -19.5% and FAC of 36.5% showed good prognostic performance. Decreased LFT-RVFW or FAC represented an independent predictor of combined event in patients with LVEF ≥ 30%. CONCLUSIONS: In NICM patients without severe LV dysfunction, decreased values of LFT-RVFW and/or FAC were associated with HF admissions, independently of RVEF.


Assuntos
Cardiomiopatia Dilatada , Insuficiência Cardíaca , Disfunção Ventricular Direita , Humanos , Estudos Retrospectivos , Imagem Cinética por Ressonância Magnética , Disfunção Ventricular Direita/diagnóstico por imagem , Disfunção Ventricular Direita/etiologia , Cardiomiopatia Dilatada/diagnóstico por imagem , Espectroscopia de Ressonância Magnética , Função Ventricular Direita , Volume Sistólico
6.
New Phytol ; 235(5): 2022-2033, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35579884

RESUMO

Plant litter decomposition is a key process for carbon (C) turnover in terrestrial ecosystems. Sunlight has been shown to cause and accelerate C release in semiarid ecosystems, yet the dose-response relationships for these effects have not been evaluated. We conducted a two-phase experiment where plant litter of three species was subjected to a broad range of cumulative solar radiation (CSR) exposures under field conditions. We then evaluated the relationships between CSR exposure and abiotic mass loss, litter quality and the subsequent biotic decomposition and microbial activity in litter. Dose-response relationships demonstrated that CSR exposure was modestly correlated with abiotic mass loss but highly significantly correlated with lignin degradation, saccharification, microbial activity and biotic decay of plant litter across all species. Moreover, a comparison of these dose-response relationships suggested that small reductions in litter lignin due to exposure to sunlight may have large consequences for biotic decay. These results provide strong support for a model that postulates a critical role for lignin photodegradation in the mechanism of photofacilitation and demonstrate that, under natural field conditions, biotic degradation of plant litter is linearly related with the dose of solar radiation received by the material before coming into contact with decomposer microorganisms.


Assuntos
Ecossistema , Exposição à Radiação , Lignina/metabolismo , Fotólise , Folhas de Planta/metabolismo , Plantas/metabolismo
7.
J Assist Reprod Genet ; 39(8): 1759-1767, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35904669

RESUMO

PURPOSE: There is increasing evidence that the ovarian extracellular matrix (ECM) plays a critical role in follicle development. The rigidity of the cortical ECM limits expansion of the follicle and consequently oocyte maturation, maintaining the follicle in its quiescent state. Quiescent primordial, primary, and secondary follicles still exist in primary ovarian insufficiency (POI) patients, and techniques as in vitro activation (IVA) and drug-free IVA have recently been developed aiming to activate these follicles based on the Hippo signaling disruption that is essential in mechanotransduction. In this context, we analyze the effect of drug-free IVA in POI patients, comparing the relationship between possible resumption ovarian function and biomechanical properties of ovarian tissue. METHODS: Nineteen POI patients according to ESHRE criteria who underwent drug-free IVA by laparoscopy between January 2018 and December 2019 and were followed up for a year after the intervention. A sample of ovarian cortex taken during the intervention was analyzed by atomic force microscopy (AFM) in order to quantitatively measure tissue stiffness (Young's elastic modulus, E) at the micrometer scale. Functional outcomes after drug-free were analyzed. RESULTS: Resumption of ovarian function was observed in 10 patients (52.6%) and two of them became pregnant with live births. There were no differences in clinical characteristics (age and duration of amenorrhea) and basal hormone parameters (FSH and AMH) depending on whether or not there was activation after surgery. However, ovarian cortex stiffness was significantly greater in patients with ovarian activity after drug-free IVA: median E = 5519 Pa (2260-11,296) vs 1501 (999-3474); p-value < 0.001. CONCLUSIONS: Biomechanical properties of ovarian cortex in POI patients have a great variability, and higher ovarian tissue stiffness entails a more favorable status when drug-free IVA is applied in their treatment. This status is probably related to an ovary with more residual follicles, which would explain a greater possibility of ovarian follicular reactivations after treatment.


Assuntos
Insuficiência Ovariana Primária , Amenorreia , Feminino , Humanos , Mecanotransdução Celular , Folículo Ovariano , Gravidez , Insuficiência Ovariana Primária/genética
8.
J Helminthol ; 96: e77, 2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36268741

RESUMO

In order to identify types of forage that inhibit pasture contamination, an evaluation was performed of the effect of the forage legumes Trifolium repens (white clover), Trifolium pratense (red clover) and Lotus corniculatus (bird's-foot-trefoil) on the survival and migration of infective larvae (L3) of gastrointestinal nematodes (GIN) of sheep. An experimental area of 441 m2 was divided into four blocks, subdivided into areas of 1.20 × 1.20 in which the three forage legumes were separately overseeded. After growth of the forage in each subdivision, experimental units were established that were later artificially contaminated with sheep faeces containing GIN eggs. Between October and December 2018, pasture, faecal and soil samples were collected on four occasions during weeks 1, 2, 4 and 8 after the deposition of faeces. In week 6, the forage legumes in all the experimental units were mown to simulate grazing. The number of L3 was quantified to determine their survival in the pasture, faeces and soil. In addition, the horizontal migration of L3 was measured at two distances from the faecal pellets (10 and 30 cm), as well as their vertical migration at two heights of the plant stems, that is, lower half and upper half. Larvae vertical migration was affected by the forage species (P < 0.001), in that bird's-foot-trefoil contained fewer larvae in the upper stratum. Bird's-foot-trefoil restricted the migration of L3 to the upper stratum of the plant, which could potentially decrease the risk of infection by intestinal nematodes in grazing sheep.


Assuntos
Fabaceae , Helmintos , Nematoides , Doenças dos Ovinos , Ovinos , Animais , Fezes , Larva , Verduras , Solo
9.
Osteoarthritis Cartilage ; 29(12): 1709-1719, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34653605

RESUMO

OBJECTIVE: Post-traumatic osteoarthritis (PTOA) is a degenerative joint disease initiated by injury. Early phase (0-7 days) treatments often include rest (unloading) and anti-inflammatory medications, but how those early interventions impact PTOA progression is unknown. We hypothesized that early unloading and anti-inflammatory treatment would diminish joint inflammation and slow PTOA progression. DESIGN: Mice were injured with non-invasive ACL rupture followed by hindlimb unloading (HLU) or normal cage activity (ground control: GC) for 7 days, after which all mice were allowed normal cage activity. HLU and GC mice were treated with daily celecoxib (CXB; 10 mg/kg IP) or vehicle. Protease activity was evaluated using in vivo fluorescence imaging, osteophyte formation and epiphyseal trabecular bone were quantified using micro-computed tomography, and synovitis and articular cartilage were evaluated using whole-joint histology at 7, 14, 21, and 28 days post-injury. RESULTS: HLU significantly reduced protease activity (-22-30% compared to GC) and synovitis (-24-50% relative to GC) at day 7 post-injury (during unloading), but these differences were not maintained at later timepoints. Similarly, trabecular bone volume was partially preserved in HLU mice at during unloading (-14-15% BV/TV for HLU mice, -21-22% for GC mice relative to uninjured), but these differences were not maintained during reloading. Osteophyte volume was reduced by both HLU and CXB, but there was not an additive effect of these treatments (HLU: -46%, CXB: -30%, HLU + CXB: -35% relative to vehicle GC at day 28). CONCLUSIONS: These data suggest that early unloading following joint injury can reduce inflammation and potentially slow PTOA progression.


Assuntos
Lesões do Ligamento Cruzado Anterior/complicações , Osteoartrite do Joelho/prevenção & controle , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Catepsinas/metabolismo , Celecoxib/farmacologia , Modelos Animais de Doenças , Fibrinolisina/metabolismo , Elevação dos Membros Posteriores , Camundongos Endogâmicos C57BL , Imagem Óptica , Osteófito/diagnóstico por imagem , Sinovite/patologia , Microtomografia por Raio-X
10.
Neurocase ; 27(1): 64-71, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33390066

RESUMO

Cotard syndrome is a clinical condition defined by the presence of nihilistic delusions. We report two patients with Cotard syndrome in whom anti-NMDAR encephalitis (ANMDARE) was confirmed. Both cases showed features of affective psychosis, developed catatonic syndrome, and worsened after the use of antipsychotics. 18F-FDG PET brain studies showed a bilateral hemispheric pattern of hypometabolism in posterior regions, mainly in the cingulate cortex and in the medial aspects of parietal and occipital lobes. A more severe hypometabolism was observed in the right hemisphere of both patients. Both cases remitted with the use of specific immunotherapy for ANMDARE.


Assuntos
Encefalite Antirreceptor de N-Metil-D-Aspartato , Encefalite Antirreceptor de N-Metil-D-Aspartato/complicações , Encefalite Antirreceptor de N-Metil-D-Aspartato/diagnóstico por imagem , Delusões , Fluordesoxiglucose F18 , Humanos , Imagem Molecular , Tomografia por Emissão de Pósitrons
11.
J Appl Microbiol ; 131(3): 1162-1176, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33547847

RESUMO

AIM: Analysing the antimicrobial activity-against food-borne micro-organisms-of modified chitosan-starch films using formic and acetic acid as chitosan solvents and Melicoccus bijugatus leaves and fruit extracts. METHODS AND RESULTS: The films' antimicrobial activity against mesophilic aerobic bacteria, total coliform and fungi were also analysed, in accordance with the Mexican Official Norms (NOM-092-SSA1-1994, NOM-111-SSA1-1994 and NOM-113-SSA1-1994). The pH values of the films and extracts were measured, and the volatile compounds of the extracts and two films were determined by Gas Chromatography-Mass Spectrometry (GC-MS) considering the relationship among the type of compounds, extracts concentration, films' pH and the antimicrobial activity against bacteria and fungi. The best results are obtained by films with formic acid and 10% (v/v) of leaf and fruit extracts, in comparison with untreated chitosan-starch films. CONCLUSIONS: The extracts' compounds improved the films' antimicrobial capacity and inhibited the growth of micro-organisms with no previous sterilization required. It is correlated to the pH of the media, the combination of solvent/extract used and its concentration. SIGNIFICANCE AND IMPACT OF THE STUDY: This is one of the few researches where the antimicrobial activity of M. bijugatus extracts is studied. It was found that the presence of these extracts is capable of improving the antimicrobial activities of chitosan-starch films. The performance of the modified films suggests their potential application as novel food packaging materials and encourages further research.


Assuntos
Anti-Infecciosos , Quitosana , Contaminação de Alimentos/prevenção & controle , Extratos Vegetais , Sapindaceae/química , Ácidos , Anti-Infecciosos/farmacologia , Quitosana/farmacologia , Microbiologia de Alimentos , Embalagem de Alimentos , Frutas/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Solventes , Amido
12.
J Sci Food Agric ; 101(1): 101-109, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32613642

RESUMO

BACKGROUND: Phytosterols are plant components with health benefits. Oleaginous seed hybridization can be relevant to increase phytosterols in diet through enriched oils. Sunflower oils obtained by press (PO) and subsequent solvent extraction (SO) from three types of phytosterol-enriched seeds were characterized. One presented a phytosterol composition of common sunflower seeds, whereas the other two were rich in campesterol and Δ7-stigmasterol, respectively. Seeds from two different harvests, 2015 and 2017, were studied. RESULTS: The type of extraction did not have a significant influence on the fatty acid composition. However, considerable differences were found between harvests. The oleic-to-linoleic ratio decreased from 0.71 in 2015 to 0.47 in 2017. The phytosterol compositions of the PO were similar to their SO homologues and no substantial differences were found between harvests. However, the SO presented higher total contents of phytosterols (4849-9249 mg kg-1 ) than the PO (2839-5284 mg kg-1 ) and the oils of 2017 showed higher levels (4476-9249 mg kg-1 ) compared to 2015 (2839-5754 mg kg-1 ). Unlike phytosterols, no significant differences were found in the tocopherol contents between the PO and SO or between harvests. The PO met Codex specifications for edible oils, except for trace metals, with concentrations close or above the limits for Cu, Fe, Pb and As. CONCLUSIONS: Differences in environmental and/or cultivation conditions between harvests may result in substantial differences in the fatty acid composition and phytosterol content in oils from the new sunflower seeds. Rigorous measures and controls to avoid trace metal contamination are required so that the PO can be considered as edible virgin oils. © 2020 Society of Chemical Industry.


Assuntos
Fracionamento Químico/métodos , Manipulação de Alimentos/métodos , Helianthus/química , Fitosteróis/química , Óleo de Girassol/química , Ácidos Graxos/química , Ácidos Graxos/isolamento & purificação , Fitosteróis/isolamento & purificação , Sementes/química , Vitamina E/análise , Vitamina E/isolamento & purificação
13.
Alzheimers Dement ; 16(1): 91-105, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31914227

RESUMO

INTRODUCTION: Leisure activities impact brain aging and may be prevention targets. We characterized how physical and cognitive activities relate to brain health for the first time in autosomal dominant frontotemporal lobar degeneration (FTLD). METHODS: A total of 105 mutation carriers (C9orf72/MAPT/GRN) and 69 non-carriers reported current physical and cognitive activities at baseline, and completed longitudinal neurobehavioral assessments and brain magnetic resonance imaging (MRI) scans. RESULTS: Greater physical and cognitive activities were each associated with an estimated >55% slower clinical decline per year among dominant gene carriers. There was also an interaction between leisure activities and frontotemporal atrophy on cognition in mutation carriers. High-activity carriers with frontotemporal atrophy (-1 standard deviation/year) demonstrated >two-fold better cognitive performances per year compared to their less active peers with comparable atrophy rates. DISCUSSION: Active lifestyles were associated with less functional decline and moderated brain-to-behavior relationships longitudinally. More active carriers "outperformed" brain volume, commensurate with a cognitive reserve hypothesis. Lifestyle may confer clinical resilience, even in autosomal dominant FTLD.


Assuntos
Cognição/fisiologia , Exercício Físico , Degeneração Lobar Frontotemporal , Atividades de Lazer , Testes Neuropsicológicos/estatística & dados numéricos , Idoso , Atrofia/patologia , Feminino , Degeneração Lobar Frontotemporal/genética , Degeneração Lobar Frontotemporal/patologia , Humanos , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade
14.
Arch Ital Biol ; 158(2): 45-56, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-33462798

RESUMO

Spatial reference memory in rodents is commonly performed in the Morris Water Maze (MWM). The use of control groups on this task is essential in order to subtract brain activity not related to learning. To study the functional contribution of selected brain areas, we assessed neuronal metabolic activity thorough quantitative cytochrome c oxidase histochemistry. This technique allows the measurement of the oxidative metabolism responsible for ATP production. Our objective is to analyse if the swimming control group is an optimal control for the evaluation of spatial reference memory task. To do so, we explore the behaviour in the MWM and the neuronal metabolic activity of motor cortex and its layers, in addition to hippocampus. For this purpose, three groups of Wistar rats were used: reference memory group, swimming control, and cage control. The behavioural results show significant differences between the experimental group and the swimming control group in time spent in the quadrants and swimming speed. In addition, higher neuronal hippocampal metabolic activity (CA1 subfield) was found in the experimental when compared to both controls. However, there are no differences in the motor cortex neuronal metabolic activity of the groups. Therefore, we can assume that the swimming control group effectively isolates the motor activity during the swim and the behavioural results are due to the hippocampal activity related to learning itself and not the physical activity performed in the labyrinth.


Assuntos
Aprendizagem em Labirinto , Memória , Córtex Motor/metabolismo , Condicionamento Físico Animal , Natação , Animais , Região CA1 Hipocampal/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Ratos , Ratos Wistar
16.
Proc Natl Acad Sci U S A ; 113(16): 4392-7, 2016 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-27044070

RESUMO

A mechanistic understanding of the controls on carbon storage and losses is essential for our capacity to predict and mitigate human impacts on the global carbon cycle. Plant litter decomposition is an important first step for carbon and nutrient turnover, and litter inputs and losses are essential in determining soil organic matter pools and the carbon balance in terrestrial ecosystems. Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in arid lands; however, the global significance of this process as a control on carbon cycling in terrestrial ecosystems is not known. Here we show that, across a wide range of plant species, photodegradation enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility to plant litter carbohydrates for microbial enzymes. Photodegradation of plant litter, driven by UV radiation, and especially visible (blue-green) light, reduced the structural and chemical bottleneck imposed by lignin in secondary cell walls. In leaf litter from woody species, specific interactions with UV radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized effect of sunlight exposure on subsequent microbial activity, mediated by increased accessibility to cell wall polysaccharides, suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release, and the carbon balance in a broad range of terrestrial ecosystems.


Assuntos
Lignina/química , Processos Fotoquímicos , Humanos
17.
Indoor Air ; 28(3): 426-440, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29377266

RESUMO

The characteristics of indoor light (intensity, spectral, spatial distribution) originating from outdoors have been studied using experimental and modeling tools. They are influenced by many parameters such as building location, meteorological conditions, and the type of window. They have a direct impact on indoor air quality through a change in chemical processes by varying the photolysis rates of indoor pollutants. Transmittances of different windows have been measured and exhibit different wavelength cutoffs, thus influencing the potential of different species to be photolysed. The spectral distribution of light entering indoors through the windows was measured under different conditions and was found to be weakly dependent on the time of day for indirect cloudy, direct sunshine, partly cloudy conditions contrary to the light intensity, in agreement with calculations of the transmittance as a function of the zenithal angle and the calculated outdoor spectral distribution. The same conclusion can be drawn concerning the position within the room. The impact of these light characteristics on the indoor chemistry has been studied using the INCA-Indoor model by considering the variation in the photolysis rates of key indoor species. Depending on the conditions, photolysis processes can lead to a significant production of radicals and secondary species.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Gases/química , Iluminação/métodos , Luminescência , Luz Solar , Planejamento Ambiental , Monitoramento Ambiental/métodos , Modelos Teóricos , Análise Espacial , Análise Espectral , Tempo (Meteorologia)
18.
Biochem Biophys Res Commun ; 492(4): 631-642, 2017 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-28343993

RESUMO

The NS2B-NS3 protease is essential for the Dengue Virus (DENV) replication process. This complex constitutes a target for efficient antiviral discovery because a drug could inhibit the viral polyprotein processing. Furthermore, since the protease is highly conserved between the four Dengue virus serotypes, it is probable that a drug would be equally effective against all of them. In this article, a strategy is reported that allowed us to identify influential residues on the function of the Dengue NS2b-NS3 Protease. Moreover, this is a strategy that could be applied to virtually any protein for the search of alternative influential residues, and for non-competitive inhibitor development. First, we incorporated several features derived from computational alanine scanning mutagenesis, sequence, structure conservation, and other structure-based characteristics. Second, these features were used as variables to obtain a multilayer perceptron model to identify defined groups (clusters) of key residues as possible candidate pockets for binding sites of new leads on the DENV protease. The identified residues included: i) amino acids close to the beta sheet-loop-beta sheet known to be important in its closed conformation for NS2b ii) residues close to the active site, iii) several residues evenly spread on the NS2b-NS3 contact surface, and iv) some inner residues most likely related to the overall stability of the protease. In addition, we found concordance on our list of residues with previously identified amino acids part of a highly conserved peptide studied for vaccine development.


Assuntos
Vírus da Dengue/enzimologia , Desenho de Fármacos , Inibidores Enzimáticos/química , Modelos Químicos , Simulação de Acoplamento Molecular/métodos , Análise de Sequência de Proteína/métodos , Proteínas não Estruturais Virais/química , Proteínas não Estruturais Virais/ultraestrutura , Sítios de Ligação , Ligação Proteica , Conformação Proteica , Domínios Proteicos
19.
Indoor Air ; 27(2): 434-442, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27317507

RESUMO

OH and HO2 profiles measured in a real environment have been compared to the results of the INCA-Indoor model to improve our understanding of indoor chemistry. Significant levels of both radicals have been measured and their profiles display similar diurnal behavior, reaching peak concentrations during direct sunlight (up to 1.6×106 and 4.0×107  cm-3 for OH and HO2 , respectively). Concentrations of O3 , NOx , volatile organic compounds (VOCs), HONO, and photolysis frequencies were constrained to the observed values. The HOx profiles are well simulated in terms of variation for both species (Pearson's coefficients: pOH =0.55, pHO2 =0.76) and concentration for OH (mean normalized bias error: MNBEOH =-30%), HO2 concentration being always underestimated (MNBEHO2 =-62%). Production and loss pathways analysis confirmed HONO photolysis role as an OH precursor (here up to 50% of the production rate). HO2 formation is linked to OH-initiated VOC oxidation. A sensitivity analysis was conducted by varying HONO, VOCs, and NO concentrations. OH, HO2 , and formaldehyde concentrations increase with HONO concentrations; OH and formaldehyde concentrations are weakly dependent on NO, whereas HO2 concentrations are strongly reduced with increasing NO. Increasing VOC concentrations decreases OH by consumption and enhances HO2 and formaldehyde.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Radical Hidroxila/análise , Compostos Orgânicos Voláteis/análise , Poluentes Atmosféricos/química , Monitoramento Ambiental , Formaldeído/análise , Radical Hidroxila/química , Oxirredução
20.
Indoor Air ; 27(2): 443-451, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27410050

RESUMO

The photolysis of HONO has been found to be the oxidation driver through OH formation in the indoor air measurement campaign SURFin, an extensive campaign carried out in July 2012 in a classroom in Marseille. In this study, the INCA-Indoor model is used to evaluate different HONO formation mechanisms that have been used previously in indoor air quality models. In order to avoid biases in the results due to the uncertainty in rate constants, those parameters were adjusted to fit one representative day of the SURFin campaign. Then, the mechanisms have been tested with the optimized parameters against other experiments carried out during the SURFin campaign. Based on the observations and these findings, we propose a new mechanism incorporating sorption of NO2 onto surfaces with possible saturation of these surfaces. This mechanism is able to better reproduce the experimental profiles over a large range of conditions.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Dióxido de Nitrogênio/química , Óxidos de Nitrogênio/química , Compostos Orgânicos Voláteis/análise , Oxirredução
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