Lanzhou lily is a famous lily variety in China, which has many advantages different from other lily varieties. It is rich in nutrients and can be used as medicine or food. The present study is ...performed to evaluate the quality of Lanzhou lily by Raman spectroscopy. Here, Raman spectra of lily bulbs were collected by confocal Raman microscopy. Through study of a variety of samples, we found that Raman peaks of several important nutrients including starch, sucrose and amino acids were clearly observed from scales of lily bulb, while strong characteristic peaks of ferulic acid were observed at the epidermis of the same scale due to the stimulation of the external environment. We also compared lily bulbs with various sizes and shapes using an average Raman spectrum of selected area. Then, changes of nutrients were quantitively analyzed in different storage period. The results show that the nutrient components including starch, sucrose, amino acids and ferulic acid can be evaluated by Raman spectroscopy. Then the quality of Lanzhou lily can be evaluated by Raman spectroscopy. This is valuable for quality evaluation of lily using non-destructive methods.
Our study is performed to evaluate the quality of Lanzhou lily by Raman spectroscopy. We found that Raman peaks of several important nutrients including starch, sucrose and amino acids were clearly observed from scales of lily bulb, while strong characteristic peaks of ferulic acid were observed at the epidermis. We also investigated the distribution of starch and protein using confocal Raman imaging, and the results were consistent with previous reports. Display omitted
•Raman spectroscopy are used to analyze the compositions of Lanzhou lily.•The sample preparation process is simple and nondestructive to biological tissue.•A series of samples with different sizes, storage time and harvest time show significant differences in Raman spectra.•The starch grains are clearly imprinted by Raman imaging, with the birefringence reflected.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The Chinese government proposes to establish a hierarchical diagnosis and treatment system, and attaches great importance to community health services. Under the background of population aging and ...the increase of older adults with disability, this study aimed to analyze the effect of spatial accessibility of community health services on the activities of daily living (ADL) among older adults in China.BackgroundThe Chinese government proposes to establish a hierarchical diagnosis and treatment system, and attaches great importance to community health services. Under the background of population aging and the increase of older adults with disability, this study aimed to analyze the effect of spatial accessibility of community health services on the activities of daily living (ADL) among older adults in China.A research sample of 7,922 older adults from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) data in 2018 was adopted. There were 2,806 participants in the treatment group and 5,116 participants in the control group. The propensity score matching method was adopted to match the treatment and control groups to calculate the values of average treatment effects on treated (ATT).MethodsA research sample of 7,922 older adults from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) data in 2018 was adopted. There were 2,806 participants in the treatment group and 5,116 participants in the control group. The propensity score matching method was adopted to match the treatment and control groups to calculate the values of average treatment effects on treated (ATT).The results of kernel density matching method showed that the factual ADL score of the treatment group was 10.912, the counterfactual ADL score of the control group was 10.694, and the ATT value was 0.218 (p < 0.01). The spatial accessibility of community health services could significantly improve the activities of daily living among older adults in China. Meanwhile, there was urban-rural heterogeneity in the impact of spatial accessibility of community health services on the activities of daily living of older adults in China. The effect value in urban samples (ATT = 0.371, p < 0.01) was higher than that in rural samples (ATT = 0.180, p < 0.01).ResultsThe results of kernel density matching method showed that the factual ADL score of the treatment group was 10.912, the counterfactual ADL score of the control group was 10.694, and the ATT value was 0.218 (p < 0.01). The spatial accessibility of community health services could significantly improve the activities of daily living among older adults in China. Meanwhile, there was urban-rural heterogeneity in the impact of spatial accessibility of community health services on the activities of daily living of older adults in China. The effect value in urban samples (ATT = 0.371, p < 0.01) was higher than that in rural samples (ATT = 0.180, p < 0.01).Spatial accessibility of community health services could improve the activities of daily living among older adults in China. The Chinese government should take actions to improve the distribution of community health service resources.ConclusionSpatial accessibility of community health services could improve the activities of daily living among older adults in China. The Chinese government should take actions to improve the distribution of community health service resources.
Resonance enhancement of Raman spectroscopy (RS) has been used to significantly improve the sensitivity and selectivity of detection for specific components in complicated environments. Resonance RS ...gives more insight into the biochemical structure and reactivity. In this field, selecting a proper excitation wavelength to achieve optimal resonance enhancement is vital for the study of an individual chemical/biological ingredient with a particular absorption characteristic. Raman spectra of three azo derivatives with absorption spectra in the visible range are studied under the same experimental conditions at 488, 532, and 633 nm excitations. Universal laws in the visible range have been concluded by analyzing resonance Raman (RR) spectra of samples. The long wavelength edge of the absorption spectrum is a better choice for intense enhancement and the integrity of a Raman signal. The obtained results are valuable for applying RR for the selective detection of biochemical constituents whose electronic transitions take place at energies corresponding to the visible spectra, which is much friendlier to biologial samples compared to ultraviolet.
Raman scattering provides stable narrow-banded signals that potentially allow for multicolor microscopic imaging. The major obstacle for the applications of Raman spectroscopy and microscopy is the ...small cross section of Raman scattering that results in low sensitivity. Here, we report a new concept of azo-enhanced Raman scattering (AERS) by designing the intrinsic molecular structures using resonance Raman and concomitant fluorescence quenching strategies. Based on the selection of vibrational modes and the enhancing unit of azobenzenes, we obtained a library of AERS molecules with specific Raman signals in the fingerprint and silent frequency regions. The spectral characterization and molecular simulation revealed that the azobenzene unit conjugated to the vibrational modes significantly enhanced Raman signals due to the mechanism of extending the conjugation system, coupling the electronic–vibrational transitions, and improving the symmetry of vibrational modes. The nonradiative decay of azobenzene from the excited state quenched the commitment fluorescence, thus providing a clean background for identifying Raman scattering. The most sensitive AERS molecules produced Raman signals of more than 4 orders of magnitude compared to 5-ethynyl-2′-deoxyuridine (EdU). In addition, a frequency tunability of 10 distinct Raman bands was achieved by selecting different types of vibrational modes. This methodology of AERS allows for designing small-molecule Raman probes to visualize various entities in complex systems by multicolor spontaneous Raman imaging. It will open new prospects to explore innovative applications of AERS in interdisciplinary research fields.
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IJS, KILJ, NUK, PNG, UL, UM, UPUK
China is a considerable grain importer in the world. However, the sustainability of China’s grain imports has been greatly challenged by its increasing economic policy uncertainty (EPU).This paper ...constructs the indicators of economic and environmental sustainability of China’s net grain imports and analyzes the impact of its EPU index on these indicators with a Time-Varying Parameter Stochastic Volatility Vector Autoregression (TVP-SV-VAR) model to explore how China’s EPU affects the sustainability of its net grain imports. The main conclusions are as follows.(1) The sustainability of China’s net grain imports fluctuated from 2001 to 2019. (2) China’s EPU has a negative impact on the economic sustainability of its net grain imports. A higher EPU index leads to a lower net import potential ratio and higher trade cost. (3) China’s EPU has a significant negative impact on the environmental sustainability of its net grain imports. It has the greatest negative impact on virtual water imports and smaller impact on virtual land imports and embodied carbon emission. Therefore, China’s EPU affects the sustainability of its net grain imports negatively through its impact on its net grain import potential ratio, trade cost, and virtual land, virtual water, and embodied carbon emissions in net grain imports.
The construction of type-II van der Waals heterostructure is an effective method to design efficient photocatalysts. In this study, we constructed the PtSe2/SiH van der Waals heterojunction, ...investigated its structural, electronic and optical properties, and discussed its application in photocatalysis. The PtSe2/SiH heterostructure is an indirect bandgap heterojunction with a 1.553 eV bandgap. The phonon dispersion curves and electron localization functions are calculated to investigate the stability of the heterojunction and the bonding mechanism between layers. According to projected density of state, it is known that PtSe2/SiH is a type-II band alignment. By calculating the work functions, the charge density difference and the plane-averaged electrostatic potential drop across the interface, we explored and discussed the interface charge transfer. In order to investigate the photocatalytic application of the PtSe2/SiH heterostructure, the band edge position and absorption coefficient were calculated. The band edge position of the heterojunction crosses the redox potential of water, indicating that it has the ability for photocatalytic water splitting. Moreover, the excellent absorption coefficient of the PtSe2/SiH heterojunction is higher than that of almost all previous studies. The absorption coefficient spans the whole region of visible light and has a peak value of 3.34 × 105 cm−1. Meanwhile, there was a peak of 4 × 105 cm−1 in the near ultraviolet region. Our results demonstrate that PtSe2/SiH has excellent properties and is a promising photocatalytic candidate.
Home care poverty is the inability of older people to access adequate home care services and their unmet needs for home care. With the increasing number of older adults (60 years old and above) with ...disability in China, the Chinese government pays more and more attention to home care. In this case, it is of great significance to explore whether older adults with the disability face home care poverty and its influencing factors. The Chinese Longitudinal Healthy Longevity Survey (CLHLS) data in 2018 were utilized. SPSS 22.0 was used as a data analysis tool to conduct descriptive statistics and multiple logistic regression analysis on the sample (n = 1932). The study found that in 2018, 48.0% of older adults with disability faced home care poverty. Multiple logistic regression results showed that degree of disability, age, rural and non-eastern regions, income poverty, family caregiver, and reluctant caregivers were positive factors that increased the risk of home care poverty in disabled older adults (p < .05). But care duration, care expenditure, social pensions insurance, community daily life care and community medical services are the positive factors to eliminate the home care poverty for older adults with disability (p < .05). In order to solve the problem of home care poverty of older adults with disability, based on the research conclusions, the study proposed to establish a long-term care insurance system, formulate supportive policies for family caregivers or their families, and establish a wide variety of community care services.
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BFBNIB, NUK, PILJ, SAZU, UL, UM, UPUK
A proper excitation wavelength is much important for the application of surface-enhanced Raman spectroscopy (SERS) in the biochemical field. Here, based on a SERS substrate model with an incident ...Gaussian beam, we investigate the dependence of the electric field enhancement on the incident wavelength of the excitation laser for popular nanostructures, including nanosphere dimer, nanorod dimer, and nanorod arrays. The results in the present manuscript indicate that both the nanosphere and nanorod dimer present a much broader plasmonic excitation wavelength range extending to the near-infrared region. The enhancement effect of Nanorod arrays is strongly dependent on the incident direction of excitation light. Finally, according to the conclusions above, a SERS substrate consisting of nanocubes based on the SPP eigen-mode is proposed and the electric field enhancement is homogeneous, and insensitive to the polarization of the incident laser. The enhancement factor is not ultrahigh; however, good homogeneousness permits for quantitative detection of lower concentration components in mixtures.
: By investigating the dependence of the electric field enhancement on the incident wavelength of the excitation laser for popular nanostructures, we propose a SERS substrate consisting of Au nanocubes based on the SPP eigenmode. The electric field enhancement is homogeneous, and insensitive to the polarization of the incident laser. Though the enhancement factor is not ultrahigh, good homogeneousness permits for quantitative detection of lower concentration components in mixtures.
Here, we investigated electronic and optical properties of AlAs/SiH heterostructure by using first principle. It is demonstrated that the AlAs/SiH heterostructure is indirect type-Ⅱ bandgap ...heterostructure with bandgap of 2.395 eV. The work functions of monolayers and heterostructure are calculated and the interface charge transfer is theoretically analyzed. The charge density difference indicates that electrons flow from SiH monolayer to AlAs monolayer, which is consistent with theoretical results of the work functions analysis. The bandedge of AlAs/SiH heterostructure straddle the redox potential of the water in pH 0 to 14, which means that AlAs/SiH has photocatalytic activity in different water environments. Furthermore, the bandgap and absorption coefficient of heterostructure can be well adjusted by changing the interfacial strain. We also found through calculation that AlAs/SiH heterostructure has an absorption peak of 2.2 × 105 cm−1 in the visible region. At −2% compressive stress, AlAs/SiH heterostructure have a peak value of 2.5 × 105 cm−1 at 3.2 eV. At 4% tensile stress, absorption spectrum can span the whole visible region. These fascinating properties indicate that AlAs/SiH heterostructure is a highly efficient photocatalyst.
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•AlAs/SiH can effectively separate photogenerated carriers.•Interfacial strain can be used to tune the optical and electrical properties of heterojunction.•Excellent absorption coefficient in visible light range.•AlAs/SiH has an excellent absorption efficiency and is a promising photocatalyst.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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