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1.
Science ; 384(6698): 878-884, 2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38781395

RESUMO

Mechanical failure and chemical degradation of device heterointerfaces can strongly influence the long-term stability of perovskite solar cells (PSCs) under thermal cycling and damp heat conditions. We report chirality-mediated interfaces based on R-/S-methylbenzyl-ammonium between the perovskite absorber and electron-transport layer to create an elastic yet strong heterointerface with increased mechanical reliability. This interface harnesses enantiomer-controlled entropy to enhance tolerance to thermal cycling-induced fatigue and material degradation, and a heterochiral arrangement of organic cations leads to closer packing of benzene rings, which enhances chemical stability and charge transfer. The encapsulated PSCs showed retentions of 92% of power-conversion efficiency under a thermal cycling test (-40°C to 85°C; 200 cycles over 1200 hours) and 92% under a damp heat test (85% relative humidity; 85°C; 600 hours).

2.
J Hazard Mater ; 460: 132349, 2023 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-37657324

RESUMO

Cadmium (Cd) pollution of soil occurs worldwide. Phytoremediation is an effective approach for cleaning up Cd polluted soil. Fast growing Populus species with high Cd uptake capacities are desirable for phytoremediation. Thus, it is important to elucidate the molecular functions of genes involved in Cd uptake by poplars. In this study, PcPLAC8-10, a homolog of Human placenta-specific gene 8 (PLAC8) implicated in Cd transport was functionally characterized in Populus × canescens. PcPLAC8-10 was transcriptionally induced in Cd-treated roots and it encoded a plasma membrane-localized transporter. PcPLAC8-10 exhibited Cd uptake activity when expressed in yeast cells. No difference in growth was observed between wild type (WT) and PcPLAC8-10-overexpressing poplars. PcPLAC8-10-overexpressing poplars exhibited increases in net Cd2+ influxes by 192% and Cd accumulation by 57% in the roots. However, similar reductions in biomass were found in WT and transgenic poplars when exposed to Cd. The complete motif of CCXXXXCPC in PcPLAC8-10 was essential for its Cd transport activity. These results suggest that PcPLAC8-10 is a plasma membrane-localized transporter responsible for Cd uptake in the roots and the complete CCXXXXCPC motif of PcPLAC8-10 plays a key role in its Cd transport activity in poplars.


Assuntos
Cádmio , Populus , Humanos , Populus/genética , Transporte Biológico , Transporte de Íons , Proteínas de Membrana Transportadoras , Saccharomyces cerevisiae , Solo , Proteínas
3.
Int J Mol Sci ; 23(14)2022 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-35886940

RESUMO

Poplars are proposed for the phytoremediation of heavy metal (HM) polluted soil. Characterization of genes involved in HM uptake and accumulation in poplars is crucial for improving the phytoremediation efficiency. Here, Natural Resistance-Associated Macrophage Protein 1 (NRAMP1) encoding a transporter involved in cadmium (Cd) uptake and transport was functionally characterized in Populus × canescens. Eight putative PcNRAMPs were identified in the poplar genome and most of them were primarily expressed in the roots. The expression of PcNRAMP1 was induced in Cd-exposed roots and it encoded a plasma membrane-localized protein. PcNRAMP1 showed transport activity for Cd2+ when expressed in yeast. The PcNRAMP1-overexpressed poplars enhanced net Cd2+ influxes by 39-52% in the roots and Cd accumulation by 25-29% in aerial parts compared to the wildtype (WT). However, Cd-induced biomass decreases were similar between the transgenics and WT. Further analysis displayed that the two amino acid residues of PcNRAMP1, i.e., M236 and P405, play pivotal roles in regulating its transport activity for Cd2+. These results suggest that PcNRAMP1 is a plasma membrane-localized transporter involved in Cd uptake and transporting Cd from the roots to aerial tissues, and that the conserved residues in PcNRAMP1 are essential for its Cd transport activity in poplars.


Assuntos
Populus , Poluentes do Solo , Biodegradação Ambiental , Transporte Biológico/genética , Cádmio/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Populus/metabolismo , Poluentes do Solo/metabolismo
4.
Tree Physiol ; 42(9): 1799-1811, 2022 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-35313352

RESUMO

To investigate the pivotal physiological processes modulating lead (Pb) tolerance capacities of poplars, the saplings of two contrasting poplar species, Populus × canescens with high Pb sensitivity and Populus nigra with relatively low Pb sensitivity, were treated with either 0 or 8 mM Pb for 6 weeks. Lead was absorbed by the roots and accumulated massively in the roots and leaves, leading to overproduction of reactive oxygen species, reduced photosynthesis and biomass in both poplar species. Particularly, the tolerance index of P. × canescens was significantly lower than that of P. nigra. Moreover, the physiological responses including the concentrations of nutrient elements, thiols, organic acids, phytohormones and nonenzymatic antioxidants, and the activities of antioxidative enzymes in the roots and leaves were different between the two poplar species. Notably, the differences in concentrations of nutrient elements, organic acids and phytohormones were remarkable between the two poplar species. A further evaluation of the Pb tolerance-related physiological processes showed that the change of 'sulfur (S) metabolism' in the roots was greater, and that of 'organic acid accumulation' in the roots and 'phytohormone regulation' in the leaves were markedly smaller in P. × canescens than those in P. nigra. These results suggest that there are differences in Pb tolerance capacities between P. × canescens and P. nigra, which is probably associated with their contrasting physiological responses to Pb stress, and that S metabolism, organic acid accumulation and phytohormone regulation are probably the key physiological processes modulating the different Pb tolerance capacities between the two poplar species.


Assuntos
Fenômenos Fisiológicos , Populus , Antioxidantes/metabolismo , Chumbo/metabolismo , Reguladores de Crescimento de Plantas , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Populus/metabolismo , Estresse Fisiológico , Enxofre/metabolismo
5.
Technol Health Care ; 30(S1): 143-153, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35124592

RESUMO

BACKGROUND: Acne vulgaris is one of the most prevalent skin conditions, which harms not only the patients' physiological conditions, but also their mental health. Early diagnosis and accurate continuous self-monitoring could help control and alleviate their discomfort. OBJECTIVE: We focus on the development and comparison of deep learning models for locating acne lesions on facial images, thus making estimations on the acne severity on faces via medical criterion. METHODS: Different from most existing literature on facial acne analysis, the considered models in this study are object detection models with convolutional neural network (CNN) as backbone and has better interpretability. Thus, they produce more credible results of acne detection and facial acne severity evaluation. RESULTS: Experiments with real data validate the effectiveness of these models. The highest mean average precision (mAP) is 0.536 on an open source dataset. Corresponding error of acne lesion counting can be as low as 0.43 ± 6.65 on this dataset. CONCLUSIONS: The presented models have been released to public via deployed as a freely accessible WeChat applet service, which provides continuous out-of-hospital self-monitoring to patients. This also aids the dermatologists to track the progress of this disease and to assess the effectiveness of treatment.


Assuntos
Acne Vulgar , Redes Neurais de Computação , Humanos , Acne Vulgar/diagnóstico , Acne Vulgar/patologia
6.
Environ Pollut ; 271: 116346, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33387784

RESUMO

To explore whether lead (Pb)-induced defense responses are responsible for the low root-to-shoot Pb translocation, we exposed saplings of the two contrasting poplar species, Populus × canescens with relatively high root-to-shoot Pb translocation and P. nigra with low Pb translocation, to 0 or 8 mM PbCl2. Pb translocation from the roots to aboveground tissues was lower by 57% in P. nigra than that in P. × canescens. Lower Pb concentrations in the roots and aerial tissues, greater root biomass, and lower ROS overproduction in the roots were found in P. nigra than those in P. × canescens treated with Pb. P. nigra roots had higher proportions of cell walls (CWs)-bound Pb and water insoluble Pb compounds, and higher transcript levels of some pivotal genes related to Pb vacuolar sequestration, such as phytochelatin synthetase 1.1 (PCS1.1), ATP-binding cassette transporter C1.1 (ABCC1.1) and ABCC3.1 than P. × canescens roots. Pb exposure induced defense responses including increases in the contents of pectin and hemicellulose, and elevated oxalic acid accumulation, and the transcriptional upregulation of PCS1.1, ABCC1.1 and ABCC3.1 in the roots of P. nigra and P. × canescens. These results suggest that the stronger defense barriers in P. nigra roots are probably associated with the lower Pb translocation from the roots to aerial tissues, and that Pb exposure-induced defense responses can enhance the barriers against Pb translocation in poplar roots.


Assuntos
Populus , Poluentes do Solo , Chumbo/toxicidade , Fitoquelatinas , Raízes de Plantas , Populus/genética , Poluentes do Solo/toxicidade
7.
Chemosphere ; 263: 128250, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297195

RESUMO

Copper(II) phthalocyanine (CuPc) and non-peripheral octamethyl-substituted copper(II) phthalocyanine (N-CuMe2Pc) were combined with reduced graphene oxide (rGO) via a precipitation method to form CuPc/rGO and N-CuMe2Pc/rGO nanocomposites, respectively. CuPc nanorods are distributed on rGO, and N-CuMe2Pc exists as nanorods and nanoparticles on rGO. The Cr(VI) removal ratio of N-CuMe2Pc/rGO exposed in simulated sunlight is 99.0% with a fast photocatalytic reaction rate of 0.0320 min-1, which is approximately 1.5 times faster than that of CuPc/rGO (0.0215 min-1) and far surpasses that of pristine phthalocyanine and rGO. As an electron acceptor, rGO can suppress the recombination of photo-induced electron-hole pairs and also can provide a large surface area for Cr(VI) removal, both of which are beneficial to the reducing capacity of the nanocomposites. The higher removal efficiency of N-CuMe2Pc/rGO compared with that of CuPc/rGO is attributed to the higher specific surface area, higher light harvesting, higher conductivity and more negative lowest unoccupied molecular orbital level of N-CuMe2Pc/rGO. The N-CuMe2Pc/rGO nanocomposite shows excellent photochemical recyclability which is essential for application in wastewater treatment.


Assuntos
Grafite , Nanocompostos , Poluentes Químicos da Água , Catálise , Cromo , Indóis , Compostos Organometálicos
8.
Plant Cell Physiol ; 61(9): 1614-1630, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32678905

RESUMO

The process of cadmium (Cd) accumulation and detoxification under different sulfur levels remains largely unknown in woody plants. To investigate the physiological and transcriptomic regulation mechanisms of poplars in response to different sulfate (S) supply levels and Cd exposure, we exposed Populus deltoides saplings to one of the low, moderate and high S levels together with either 0 or 50 µM Cd. Cd accumulation was decreased in low S-treated poplar leaves, and it tended to be increased in high S-supplied leaves under the Cd exposure condition. Sulfur nutrition was deficient in low S-supplied poplars, and it was improved in high S-treated leaves. Cd exposure resulted in lower sulfur level in the leaves supplied with moderate S, it exacerbated a Cd-induced sulfur decrease in low S-treated leaves and it caused a higher sulfur concentration in high S-supplied leaves. In line with the physiological changes, a number of mRNAs and microRNAs (miRNAs) involved in Cd accumulation and sulfur assimilation were identified and the miRNA-mRNA networks were dissected. In the networks, miR395 and miR399 members were identified as hub miRNAs and their targets were ATP sulfurylase 3 (ATPS3) and phosphate 2 (PHO2), respectively. These results suggest that Cd accumulation and sulfur assimilation are constrained by low and enhanced by high S supply, and Cd toxicity is aggravated by low and relieved by high S in poplar leaves, and that miRNA-mRNA regulatory networks play pivotal roles in sulfur-mediated Cd accumulation and detoxification in Cd-exposed poplars.


Assuntos
Cádmio/metabolismo , MicroRNAs/fisiologia , Folhas de Planta/metabolismo , Populus/metabolismo , RNA Mensageiro/fisiologia , RNA de Plantas/fisiologia , Enxofre/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Redes Reguladoras de Genes/genética , Redes Reguladoras de Genes/fisiologia , MicroRNAs/metabolismo , Populus/genética , RNA Mensageiro/metabolismo , RNA de Plantas/metabolismo
9.
Sci Total Environ ; 736: 139185, 2020 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-32485365

RESUMO

Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) are among the contaminants of concern in aquaculture ponds due to their frequent detection and high bioaccumulation in aquatic products and hence high dietary risks to human beings. In this study, magnetic activated carbon (MAC) was added as a stabilization and removal adsorbent to native pond sediment with known contamination of HMs and PAHs to reduce the tissue residues and dietary risks of HMs and PAHs in a model aquaculture species (Venerupis philippinarum) in the course of a 28-day bioaccumulation experiment. Meanwhile, passive sampling techniques based on diffusive gradient in thin films (DGT) and polydimethylsiloxane (PDMS) were applied to sense the bioavailable fraction of HMs and PAHs in sediment during the stabilization process. The results showed that 3% dosage of MAC to sediment achieved the most cost-effective stabilization for HMs and PAHs. A remarkable decrease was observed with the tissue residues of HMs and PAHs in V. philippinarum (28-47% for HMs and ~76% for ∑PAHs), which was quantitatively linked to the decline in their bioavailable concentrations in sediment pore water (31-46% for HMs and ~76% for ∑PAHs). Consequently, the target hazard quotients (THQs) posed by HMs and incremental lifetime cancer risks (ILCRs) by PAHs in V. philippinarum were reduced by 38% and 46%, respectively. Along with the magnetic recovery of ~70% MAC from the sediment, HMs (4.8-13%) and PAHs (2-60%) can be effectively removed. We further established a multi-domain equilibrium sorption model that was able to predict the optimal amendment of MAC for quantitative mitigation of bioavailable PAHs in sediment pore water within a certain range of MAC dosage. Future studies are warranted to explore the applicability domain of MAC for in situ remediation in aquaculture ponds to ensure the quality of farming organisms or to serve other purposes in aquatic systems.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Animais , Aquicultura , Disponibilidade Biológica , Carvão Vegetal , Monitoramento Ambiental , Sedimentos Geológicos , Humanos , Fenômenos Magnéticos , Lagoas
10.
Plant Cell Physiol ; 60(11): 2478-2495, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31368491

RESUMO

Although poplar plantations are often established on nitrogen (N)-poor soil, the physiological and molecular mechanisms underlying wood properties of poplars in acclimation to low N availability remain largely unknown. To investigate wood properties of poplars in acclimation to low N, Populus � canescens saplings were exposed to either 50 (low N) or 500 (normal N) �M NH4NO3 for 2 months. Low N resulted in decreased xylem width and cell layers of the xylem (the number of cells counted along the ray parenchyma on the stem cross section), narrower lumina of vessels and fibers, greater thickness of double fiber walls (the walls between two adjacent fiber cells), more hemicellulose and lignin deposition, and reduced cellulose accumulation in poplar wood. Consistently, concentrations of gibberellins involved in cell size determination and the abundance of various metabolites including amino acids, carbohydrates and precursors for cell wall biosynthesis were decreased in low N-supplied wood. In line with these anatomical and physiological changes, a number of mRNAs, long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) were significantly differentially expressed. Competing endogenous RNA regulatory networks were identified in the wood of low N-treated poplars. Overall, these results indicate that miRNAs-lncRNAs-mRNAs networks are involved in regulating wood properties and physiological processes of poplars in acclimation to low N availability.


Assuntos
Aminoácidos/metabolismo , Metabolômica/métodos , Reguladores de Crescimento de Plantas/metabolismo , Populus/metabolismo , Aminoácidos/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Populus/genética , Xilema/genética , Xilema/metabolismo
11.
Sci Total Environ ; 687: 679-686, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31220721

RESUMO

To assess the remediation effectiveness of ecological restoration in the transition period from construction to operation of Yangshan Port, the largest deepwater port of East China Sea, we employed equilibrium passive sampling and partitioning theory to assess the changing bioavailability and flux of polycyclic aromatic hydrocarbons (PAHs) in relation to bioaccumulation and ecological risks in marine organisms. Due to the ecological restoration efforts, both the bulk and bioavailable concentrations of PAHs in sediment and surface seawater samples decreased dramatically after the port entered the operation phase, as compared with those reported during the last construction phase. PAH concentrations in the marine organisms also showed a dramatic decline, and corresponded to the change in the freely dissolved fractions of PAHs in sediment/surface water according to their thermodynamic potential for bioaccumulation. While trophic magnification of ΣPAHs was observed in the pelagic communities, concentrations of PAHs in benthic species were relatively consistent across multiple trophic levels, and were generally higher than those in pelagic species. The differing bioaccumulation between benthic and pelagic species may be related to the habitat-specific bioavailability of PAHs and the prey-predator relations among different species. The incremental lifetime cancer risks (ILCR) of PAHs in marine organisms also dropped by nearly three orders of magnitude, and were lower than the guideline (1 × 10-6) proposed by the U.S. EPA, except for several species at higher trophic levels. Overall, our study highlights an integrated use of passive sampling and equilibrium partitioning theory as a robust tool that can be applied to assess the effectiveness of ecological remediation in the port environment with quantitative, mechanistic insights from bioavailability to bioaccumulation.


Assuntos
Monitoramento Ambiental , Recuperação e Remediação Ambiental , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Sedimentos Geológicos
12.
J Hazard Mater ; 362: 275-285, 2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30243250

RESUMO

To shed light on physiological mechanisms underlying abscisic-acid (ABA)-mediated lead (Pb) uptake, translocation and detoxification, we exposed Populus × canescens saplings to either 0 or 3 mM Pb2+ in combination with either 0 or 10 µM exogenous ABA. Pb was taken up by the roots and accumulated mainly in the cortex. A fraction of the Pb in the roots was translocated to the leaves, thereby resulting in decreased photosynthesis and biomass. Pb accumulation caused a burst of reactive oxygen species (ROS), with higher concentrations of total thiols, glutathione, and ascorbate in the roots and/or leaves. Exogenous ABA stimulated Pb uptake, decreased Pb deposition in the cortex, and enhanced Pb vascular loading in the roots. Exogenous ABA alleviated the Pb-induced reductions in photosynthesis and root biomass, and decreased Pb-triggered ROS overproduction in the roots and/or leaves. Correspondingly, exogenous ABA stimulated the mRNA levels of a few genes involved in Pb uptake, transport, and detoxification, including NRAMP1.4, ABCG40, FRD3.1, PCS1.1, and ABCC1.1. These results suggest that exogenous ABA enhances Pb uptake and translocation, and alleviates Pb toxicity in poplars through the ABA-induced movement of Pb from the root cortex to the vascular stele, and transcriptionally regulated key genes involved in Pb tolerance.


Assuntos
Ácido Abscísico/química , Chumbo/toxicidade , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Populus/metabolismo , Adsorção , Antioxidantes/metabolismo , Ácido Ascórbico/metabolismo , Regulação da Expressão Gênica de Plantas , Glutationa/metabolismo , Estresse Oxidativo , Fotossíntese , Filogenia , Espécies Reativas de Oxigênio/metabolismo , Compostos de Sulfidrila/química
13.
J Phys Chem Lett ; 7(19): 3990-4000, 2016 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-27681200

RESUMO

An important challenge in the study of conjugated organic materials is to relate the properties of transient states underlying macroscopic material responses directly with intra- and intermolecular structure. We discuss recent efforts using the vibrational sensitivity of time-resolved Raman spectroscopy to interrogate structural properties of transient excited and charge-separated states in conjugated oligomers and polymers in order to relate them to molecular conformations and material microstructures. We focus on recent work with excited-state Raman spectroscopy that provides mode-specific signatures of structural relaxation in oligo- and polythiophenes, examination of structural heterogeneities associated with exciton localization in different structural motifs of amorphous polymers, and interrogation of correlations between microstructure and properties and dynamics of charge-separated states within polymer aggregates. On the basis of these recent efforts, we provide an outlook for further applying this method to elucidate relationships between the structure and properties of transient states and the photoresponses of conjugated materials.

14.
J Phys Chem B ; 120(22): 5093-102, 2016 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-27167593

RESUMO

Transient hole-burning and resonantly enhanced Raman spectroscopies are used to probe heterogeneities among localized singlet excitons of poly(3-hexylthiophene) in solution. Transient hole-burning spectroscopy facilitated by population dumping through wavelength-selective stimulated emission exposes inhomogeneous broadening of the exciton absorption band in the near-infrared, as reflected by correlations between stimulated emission and excited-state absorption transition energies. Dump-induced spectral diffusion of the exciton absorption band reflects structural fluctuations in the locally excited polymer. This diffusion is observed to occur slightly faster or slower than the nonequilibrium relaxation that follows direct excitation of the polymer (8-9 ps), with the time scale for diffusion varying with subpopulation: dumping across small vs large band gaps results in diffusion over 5 vs 35 ps, respectively. Furthermore, incomplete spectral relaxation of transient holes reflects that subsets of locally excited structural motifs prepared through photoexcitation cannot interchange through structural fluctuations that occur over the singlet-exciton lifetime. Raman spectra of the C═C/C-C stretching region collected in resonance at energies across the exciton absorption band exhibit frequency and intensity trends (Raman "dispersion") ascribed to variation in the local effective conjugation length. Together, results explicitly reveal heterogeneities among excitonic states associated with variations and fluctuations in local conformational order.

15.
J Phys Chem Lett ; 6(17): 3496-502, 2015 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-26291543

RESUMO

Ultrafast structural relaxation of photoexcited 2,2':5',2″:5″,2‴-quaterthiophene (4T) and 3,3‴-Dihexyl-2,2':5',2″:5″,2‴-quaterthiophene (DH4T) in solution were interrogated with femtosecond stimulated Raman spectroscopy (FSRS). Relaxation was observed through time-dependent evolution in frequencies and intensity ratios of out-of-phase (Z) and in-phase (Я) intraring C═C stretching features. Frequency shifts occurred on time scales of 0.4 and 0.86 ps, respectively, dominated by a blue shift in the Z mode (6.2 and 11.5 cm(-1) shifts for 4T and DH4T, respectively). Intensity ratios evolved on similar time scales due to correlated intensity decreases and increases of Z- and Я-mode features. Excited-state quantum-chemical calculations with bithiophene demonstrate that mode frequencies are coupled to the torsional dihedral, such that the spectral evolution observed reflects excited-state relaxation toward a planar conformation. This work demonstrates the power of ultrafast Raman spectroscopy for probing dynamics in photoexcited conjugated materials with structural detail given the parametric dependence of intraring vibrational modes on interring torsional dihedrals.

16.
Food Chem ; 186: 239-43, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-25976816

RESUMO

The paper study the functional properties of hemicellulose B (RBHB) and rice bran insoluble dietary fibre (RBDF) to develop an acceptable low fat meat product enriched with high content fibre from defatted rice bran. Meatballs were produced with three different formulations including 2%, 4% and 6% RBHB or RBDF addition. The total trans fatty acids were lower and the ratio of total unsaturated fatty acids to total saturated fatty acids was higher in the samples with added RBHB than in the control meatballs. Meatballs containing RBHB had lower concentrations of total fat and total trans fatty acids than the control samples. Sensory evaluations revealed that meatballs with 2%, 4% and 6% RBHB were overall acceptable. This confirms that the RBHB preparation from defatted rice bran has great potential in food applications, especially in development of functional foods including functional meat products.


Assuntos
Celulose/análise , Fibras na Dieta/análise , Carne/análise , Oryza/química , Celulose/administração & dosagem , Celulose/isolamento & purificação , Gorduras na Dieta/análise , Manipulação de Alimentos , Alimentos Fortificados , Alimento Funcional , Humanos , Ácidos Graxos trans
17.
J Chem Phys ; 141(4): 044201, 2014 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-25084903

RESUMO

A combination of transient absorption (TAS) and femtosecond stimulated Raman (FSRS) spectroscopies were used to interrogate the photo-induced nuclear relaxation dynamics of poly(3-cyclohexyl,4-methylthiophene) (PCMT). The large difference in inter-ring dihedral angles of ground and excited-state PCMT make it an ideal candidate for studying large-amplitude vibrational relaxation associated with exciton trapping. Spectral shifting in the S1 TA spectra on sub-ps timescales (110 ± 20 and 800 ± 100 fs) is similar to spectroscopic signatures of excited-state relaxation observed with related photoexcited conjugated polymers and which have been attributed to exciton localization and a combination of resonant energy transfer and torsional relaxation, respectively. Measurements made with both techniques reveal fast PCMT S1 decay and triplet formation (τS1 = 25-32 ps), which is similar to the excited-state dynamics of short oligothiophenes and highly twisted polyconjugated molecules. On ultrafast timescales FSRS of S1 PCMT offers a new perspective on the nuclear dynamics that underlie localization of excitons in photoexcited conjugated polymers: Spectral dynamics in the C=C stretching region (1400-1600 cm(-1)) include a red-shift of the in-phase C=C stretching frequency, as well as a change in the relative intensity of in-phase and out-of-phase stretch intensities on a timescale of ∼100 fs. Both changes indicate an ultrafast vibrational distortion that increases the conjugation length in the region of the localized excitation and are consistent with exciton self-localization or trapping. Wavelength-dependent excited-state FSRS measurements further demonstrate that the C=C stretching frequency provides a useful spectroscopic handle for interrogating the degree of delocalization in excited conjugated polymers given the selectivity achieved via resonance enhancement.

18.
PLoS One ; 9(8): e104207, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25166137

RESUMO

Understanding norms is a key challenge in sociology. Nevertheless, there is a lack of dynamical models explaining how one of several possible behaviors is established as a norm and under what conditions. Analysing an agent-based model, we identify interesting parameter dependencies that imply when two behaviors will coexist or when a shared norm will emerge in a heterogeneous society, where different populations have incompatible preferences. Our model highlights the importance of randomness, spatial interactions, non-linear dynamics, and self-organization. It can also explain the emergence of unpopular norms that do not maximize the collective benefit. Furthermore, we compare behavior-based with preference-based punishment and find interesting results concerning hypocritical punishment. Strikingly, pressuring others to perform the same public behavior as oneself is more effective in promoting norms than pressuring others to meet one's own private preference. Finally, we show that adaptive group pressure exerted by randomly occuring, local majorities may create norms under conditions where different behaviors would normally coexist.


Assuntos
Comportamento Cooperativo , Modelos Teóricos , Normas Sociais , Simulação por Computador , Humanos , Punição
19.
Int J Food Sci Nutr ; 64(4): 461-6, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23215624

RESUMO

The objective of this study was to investigate the possibility of using hemicellulose from rice bran to scavenge cholesterol and bile acid in vitro study. This paper demonstrates that rice bran hemicellulose A (RBHA), rice bran hemicellulose B (RBHB) and rice bran hemicellulose C (RBHC) have the potential for binding cholesterol and bile acid. The quantity of cholesterol and bile acid bound varies from one rice bran fibre to another. As it can be inferred from the results of the study, RBHB was characterized by the highest capacity for cholesterol binding, followed by RBHC and RBHA. Binding of cholesterol and bile acid to rice bran insoluble dietary fibre (RBDF) and cellulose from rice bran was found to be poor. Lignin from rice bran was the least active fraction for binding cholesterol and bile acid. This confirms that the RBHB preparation from defatted rice bran has great potential in food applications, especially in the development of functional foods.


Assuntos
Ácidos e Sais Biliares/química , Celulose/química , Colesterol/química , Fibras na Dieta/farmacologia , Oryza/química , Polissacarídeos/química , Sementes/química , Anticolesterolemiantes/química , Anticolesterolemiantes/farmacologia , Ácidos e Sais Biliares/metabolismo , Colesterol/metabolismo , Dieta , Alimento Funcional , Humanos , Lignina/química , Preparações de Plantas/química , Preparações de Plantas/farmacologia
20.
Sci Rep ; 2: 870, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23162694

RESUMO

The use of nanomaterials for strain sensors has attracted attention due to their unique electromechanical properties. However, nanomaterials have yet to overcome many technological obstacles and thus are not yet the preferred material for strain sensors. In this work, we investigated graphene woven fabrics (GWFs) for strain sensing. Different than graphene films, GWFs undergo significant changes in their polycrystalline structures along with high-density crack formation and propagation mechanically deformed. The electrical resistance of GWFs increases exponentially with tensile strain with gauge factors of ~10(3) under 2~6% strains and ~10(6) under higher strains that are the highest thus far reported, due to its woven mesh configuration and fracture behavior, making it an ideal structure for sensing tensile deformation by changes in strain. The main mechanism is investigated, resulting in a theoretical model that predicts very well the observed behavior.

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