Effects of spatial accessibility of community health services on the activities of daily living among older adults in China: a propensity score matching study.

Background: 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. Methods: 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). Results: 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). Conclusion: 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.

The Effect of Home Care Poverty on the Activities of Daily Living among Older Adults in China: A Propensity Score Matching Study.

Background: In the context of home care being valued by the Chinese government and the increasing number of disabled older adults, it is of great significance to explore the effect of home care poverty of the older adults on their ability to perform activities of daily living. Methods: A research sample of 2583 older adults from the Chinese Longitudinal Healthy Longevity Survey data in 2018 was adopted. There were 422 participants in the treatment group and 2161 participants in the control group. According to the framework of counterfactual analysis, the kernel matching method was used to match the treatment and control groups to calculate the values of average treatment effects on treated (ATT). Results: The results of the kernel matching method showed that the factual ADL score of the treatment group was 6.886, the counterfactual ADL score of the control group was 8.520, and the ATT value was -1.634 (P<0.05). There were gender and urban-rural differences in the relationship between home care poverty and activities of daily living among older people. In gender samples, there was a significant correlation between the two, and the absolute value of ATT in male samples was higher than that in female samples (P<0.05). In the rural samples, there was a significant correlation between the two variables (P<0.05). But in the urban samples, there was no significant correlation between the two variables. Conclusion: Home care poverty could significantly reduce the ability to perform activities of daily living among older adults in China. Based on the conclusions, the study puts forward several suggestions to solve the home care poverty for the older adults in China.

Combining Raman spectroscopy and machine learning to assist early diagnosis of gastric cancer.

Gastric cancers, with gastric adenocarcinoma (GAC) as the most common histological type, cause quite a few of deaths. In order to improve the survival rate after GAC treatment, it is important to develop a method for early detection and therapy support of GAC. Raman spectroscopy is a potential tool for probing cancer cell due to its real-time and non-destructive measurements without any additional reagents. In this study, we use Raman spectroscopy to examine GAC samples, and distinguish cancerous gastric mucosa from normal gastric mucosa. Average Raman spectra of two groups show differences at 750 cm-1, 1004 cm-1, 1449 cm-1, 1089-1128 cm-1, 1311-1367 cm-1 and 1585-1665 cm-1, These peaks were assigned to cytochrome c, phenylalanine, phospholipid, collagen, lipid, and unsaturated fatty acid respectively. Furthermore, we build a SENet-LSTM model to realize the automatic classification of cancerous gastric mucosa and normal gastric mucosa, with all preprocessed Raman spectra in the range of 400-1800 cm-1 as input. An accuracy 96.20% was achieved. Besides, by using masking method, we found the Raman spectral features which determine the classification and explore the explainability of the classification model. The results are consistent with the conclusions obtained from the average spectrum. All results indicate it is potential for pre-cancerous screening to combine Raman spectroscopy and machine learning.

Characteristics, formation, and sources of PM2.5 in 2020 in Suzhou, Yangtze River Delta, China.

Here we present seasonal chemical characteristics, formations, sources of PM2.5 in the year 2020 in Suzhou, Yangtze River Delta, China. Expectedly, organic matter (OM) found to be the most dominant component of PM2.5, with a year-average value of 10.3 ± 5.5 µg m-3, followed by NO3- (6.7 ± 6.5 µg m-3), SO42- (3.3 ± 2.5 µg m-3), NH4+ (3.2 ± 2.8 µg m-3), EC (1.1 ± 1.3 µg m-3), Cl- (0.57 ± 0.56 µg m-3), Ca2+ (0.55 ± 0.91 µg m-3), K+ (0.2 ± 1.0 µg m-3), Na+ (0.18 ± 0.45 µg m-3), and Mg2+ (0.09 ± 0.15 µg m-3). Seasonal variations of PM2.5 showed the highest average value in spring, followed by winter, fall, and summer. Meanwhile, the formation mechanisms of the major PM2.5 species (NO3-, SO42-, and OM) varied in seasons. Interestingly, NO2 may have the highest conversion rate to NO3- in spring, which might be linked with the nighttime chemistry due to the high relative humidity. Moreover, OM in summer was mainly produced by the daytime oxidation of volatile organic compounds, while local primary organic aerosols might play a significant role in other seasons. Source apportionment showed that the more-aged PM2.5 contributed significantly to the PM2.5 mass (42%), followed by the dust-related PM2.5 (38%) and the less-aged PM2.5 (21%). Potential contribution source function (PSCF) results indicated that aged PM2.5 were less affected by transportation than dust-related PM2.5.

Azo-Enhanced Raman Scattering for Enhancing the Sensitivity and Tuning the Frequency of Molecular Vibrations.

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.

Evaluation of nutrition components in Lanzhou lily bulb by confocal Raman microscopy.

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.

PtSe2/SiH van der Waals type-II heterostructure: a high efficiency photocatalyst for water splitting.

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.

Study of the GaAs/SiH van der Waals type-II heterostructure: a high efficiency photocatalyst promoted by a built-in electric field.

The application of two-dimensional (2D) materials to construct van der Waals (vdW) heterostructures in photocatalysis has attracted extensive attention recently. However, exploration of ways to enhance the photocatalytic efficiency at the interface is relatively limited. In this study, using density functional theory, we prove that GaAs/SiH formed a standard type-II heterojunction with a 2.17 eV direct band gap. The charge transfer across the interface was investigated by the charge density difference and Bader charge analysis. Due to the difference in the work functions, the relative positions of the conduction band (CB) and valence band (VB) of GaAs and SiH present a significant change after the heterostructure is formed. Furthermore, the built-in electric field, formed by charge transfer at the interface of the GaAs/SiH heterojunction, promotes photogenerated carrier separation. The band edge position and the absorption spectrum were calculated and the photocatalytic performance of the GaAs/SiH vdW heterostructure in the visible light region was evaluated. Strong absorption is observed, which predicts promising application in photonic detection across the visible and the UV region. Excitingly, GaAs/SiH has a significant advantage for improving the photocatalytic efficiency under visible light irradiation. Our work can provide guidance for the design of other highly efficiency heterostructures.

Solution-phase vertical growth of aligned NiCo2O4 nanosheet arrays on Au nanosheets with weakened oxygen-hydrogen bonds for photocatalytic oxygen evolution.

Vertical heterojunctions of two-dimensional (2D) semiconducting materials have attracted more and more research interest recently due to their unique optical, electrical, and catalytic properties and potential applications. Although great progress has been made, vertical integration of the layered materials formed by 2D semiconductor nanosheets and 2D plasmatic metal nanosheets remains a huge challenge. Here, we demonstrate for the first time a solution-phase growth of vertical plasmatic metal-semiconductor heterostructures in which aligned NiCo2O4 nanosheet arrays vertically grow on a single Au nanosheet, forming vertically aligned NiCo2O4-Au-NiCo2O4 sandwich-type heterojunctions with hierarchical open channels. Such vertical NiCo2O4-Au-NiCo2O4 heterojunctions can effectively promote the separation and transfer of a photoinduced charge. Density functional theory (DFT) studies and time-resolved transient absorption spectroscopy show that electrons transfer from NiCo2O4 to Au, and the formation of the heterojunction weakens the H-O bond of H2O. Due to the unique structure and superiority of the component, the vertical NiCo2O4-Au-NiCo2O4 heterojunctions exhibit significant activity with an O2 production rate of up to 33 µmol h-1 and long-term stability for photocatalytic water oxidation. We calculated the apparent quantum efficiency (AQE) to be 21.9% for NiCo2O4-Au-NiCo2O4 heterojunctions at the wavelength λ = 450 ± 10 nm, which is higher than that of NiCo2O4 nanosheets (10.9%), Au nanosheets (0.96%) and other photocatalysts. The present study paves the way for the controlled synthesis of novel vertical heterojunctions based on 2D semiconductor nanosheets and 2D metal nanosheets for efficient photocatalysis.

Liver changes induced by cadmium poisoning distinguished by confocal Raman imaging.

Heavy metal pollution has become an important issue threatening human health and the liver is a very important metabolic organ. Here, we use label-free Raman confocal imaging to study the alterations of the liver tissue after cadmium pollution. Raman imaging has been performed on 100µmx100µm liver tissues to study the distribution of important macromolecules and the average Raman spectrum of the entire region has been used to characterize and quantize the change of biochemical compositions in liver tissue. The poisoned livers displayed a significant decrease in the intensity of 748 cm-1, 1128 cm-1 and 1585 cm-1 bands of cytochrome C, in comparison to the control. The collagen peak at 1082 cm-1 is significantly higher than that of control, suggesting the increasing fibrosis of Cd liver tissues. To confirm the results, we selected a 30µmx15µm liver cell area for high-resolution Raman imaging. We observed a substantial increase of lipids and proteins at specific points of hepatocytes. The confocal Raman imaging of liver tissues provided a unique tool to better understand disease-induced changes in the biochemical phenotype of primary liver tissues. Our study provides valuable references as in vitro models for studying Cd accumulation and toxicity in human liver.

Photoninduced charge redistribution of graphene determined by edge structures in the infrared region.

By using the ab initio density-functional theory method, we investigated the charge redistribution of monolayer graphene with ZigZag and/or ArmChair edges upon infrared excitation. The photoinduced charge redistribution is strongly dependent on edge types. The priority of electrons transfer has been revealed by charge density difference. To further investigate the influence of edge types on optical properties, the dielectric constants and absorption coefficient of graphene with various edge types have been calculated. The edge types have a non-negligible influence on optical properties of graphene, and the Zigzag edge graphene owns stronger optical absorption in infrared region. Our results are potentially beneficial for designing graphene nanodevices in the infrared region.

Investigation of the mechanism of overall water splitting in UV-visible and infrared regions with SnC/arsenene vdW heterostructures in different configurations.

Monolayer arsenene presents good stability and high photogenic carrier mobility. However, a high photogenic electron and hole pair recombination rate seriously reduces its photocatalytic activity. The photocatalytic activity can be effectively improved by building type II heterostructures. In this work, SnC/arsenene heterostructures in three configurations are studied using first-principles calculations. Their structure, stability, and electronic and photocatalytic properties are investigated. It is found that all SnC/arsenene heterostructures are stable, and form type-II band edges, which effectively promote the transfer of photogenerated electrons from the SnC monolayer to the arsenene sheet. The charge transfer between SnC and arsenene leads to a built-in electric field in the interface region, which is favorable for inhibiting photogenic electron and hole pair recombination. Compared with the monolayer arsenene, the photocatalytic activity is greatly improved and the absorption spectrum of SnC/arsenene heterostructures is expanded. Attractively, these three heterostructures present two different photocatalytic mechanisms. H1 and H3 configurations were taken as examples to study their photocatalytic properties for overall water splitting at varying pH values and external strains. We found that alkaline conditions were more favorable for photocatalysis of SnC/arsenene heterostructures. In particular, H3 can still achieve full photocatalytic water decomposition in the near infrared region. These results show that the SnC/arsenene heterostructures are a prospective material for photocatalysis application.

Ex vivo detection of cadmium-induced renal damage by using confocal Raman spectroscopy.

Cadmium (Cd) is a toxic heavy metal which is harmful to environment and organisms. The reabsorption of Cd in kidney leads it to be the main damaged organ in animals under the Cd exposure. In this work, we applied confocal Raman spectroscopy to map the pathological changes in situ in normal and Cd-exposed mice kidney. The renal tissue from Cd-exposed group displayed a remarkable decreasing in the intensity of typical peaks related to mitochondria, DNA, proteins and lipids. On the contrary, the peaks of collagen in Cd-exposed group elevated significantly. The components in each tissue were identified and distinguished by principal component analysis. Furthermore, all the biological investigations in this study were consistent with the Raman spectrum detection, which revealed the progression and degree of lesion induced by Cd. The confocal Raman spectroscopy provides a new perspective for in situ monitoring of substances changes in tissues, which exhibits more comprehensive understanding of the pathogenic mechanisms of heavy metals in molecular toxicology.

Physical mechanism on edge-dependent electrons transfer in graphene in mid infrared region.

In this paper, we report nanophotonic properties of single layer graphene with Zigzag and/or armchair edge in the region of Mid Infrared (Mid-IR). The photoinduced charge transfer of graphene can occur in electronic state transition of Mid-IR region, and then the transferred electrons can interact with the phonon of graphene at Mid-IR. The coupling excitation of photon and phonon (graphene plasmon) can results in photon-electron-phonon interactions, which can significantly enhance resonance Raman scattering of Mid-IR region, which is so called "graphene plasmon-enhanced resonance Raman scattering of Mid-IR region". The photoinduced charge transfers are strongly dependent on the kinds of edge structures of Zigzag and/or armchair, which are revealed by charge difference density. It is found that the edge structures of Zigzag and/or armchair play the most important role on the orientation of charge transfer. The analysis of molecular orbital Pipek-Mezey localization reveals the nature of edge structure on the occurrence or not photoinduced charge transfer. Our results can promote deeper understanding nanophotonic mechanism of Mid Infrared graphene and can be potentially used in the design of optical device based on Mid Infrared graphene.

A Novel Pre-Processing Algorithm Based on the Wavelet Transform for Raman Spectrum.

Noise and fluorescent background are two major problems for acquiring Raman spectra from samples, which blur Raman spectra and make Raman detection or imaging difficult. In this paper, a novel algorithm based on wavelet transform that contains denoising and baseline correction is presented to automatically extract Raman signals. For the denoising section, the improved conventional-scale correlation denoising method is proposed. The baseline correction section, which is performed after denoising, basically consists of five aspects: (1) detection of the peak position; (2) approximate second derivative calculation based on continuous wavelet transform is performed using the Haar wavelet function to find peaks and background areas; (3) the threshold is estimated from the peak intensive area for identification of peaks; (4) correction of endpoints, spectral peaks, and peak position; and (5) determine the endpoints of the peak after subtracting the background. We tested this algorithm for simulated and experimental Raman spectra, and a satisfactory denoising effect and a good capability to correct background are observed. It is noteworthy that this algorithm requires few human interventions, which enables automatic denoising and background removal.

Formation of porous Cu hydroxy double salt nanoflowers derived from metal-organic frameworks with efficient peroxidase-like activity for label-free detection of glucose.

Currently, nanomaterials with peroxidase activity have become an important colorimetric tool for biomolecular detection. However, compared with natural enzymes, the efficiency of most nanozymes is still lower. Here, with a leaf-like metal-organic-framework-5 as both a precursor and a template and copper acetate as a second precursor, hierarchical Cu hydroxy double salt (HDS) nanoflowers have been prepared and used as a label-free glucose colorimetric detection platform. We have demonstrated a scalable and facile synthesis of hierarchical Cu HDS nanoflowers, and density functional theory (DFT) calculations confirmed that there exists a hydrogen bond between the terephthalate anions and the layer OH group. The composition of Cu hydroxyl double salt is [Cu4(OH)6][BDC]·2H2O. Importantly, for the first time, the as-prepared Cu HDSs were demonstrated as peroxidase mimics to catalyze the oxidation of the enzyme substrate, 3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2, which accompanies a color change from colorless to blue and followed classic Michaelis-Menten models. Based on these findings, a colorimetric method based on Cu HDSs that is highly sensitive and selective for the detection of glucose was developed, with a low detection limit of 0.5 µM. The clinical applicability of the sensor is also proven to be suitable for sensing glucose in blood, suggesting that Cu HDSs could be used in the construction of portable sensors for point-of-care diagnosis and on-site tests.

Panax notoginseng saponins mitigate cisplatin induced nephrotoxicity by inducing mitophagy via HIF-1α.

We investigated the role of HIF-1α in the mitigation of cisplatin-induced nephrotoxicity by Panax notoginseng saponins (PNS) in a rat model. Serum creatinine (Scr), blood urea nitrogen (BUN) and urinary N-acetyl-ß-D-glucosaminidase (NAG) levels were all elevated in cisplatin treated rats. PNS reduced Scr, BUN and NAG levels in the presence or absence of the HIF-1α inhibitor 2-methoxyestradiol (2ME2). PNS also reduced the high tubular injury scores, which corresponded to renal tubular damage in cisplatin-treated rats and which were exacerbated by 2ME2. Renal tissues from PNS-treated rats showed increased HIF-1α mRNA and nuclear localized HIF-1α protein. Moreover, PNS treatment increased BNIP3 mRNA as well as LC3-II, BNIP3 and Beclin-1 proteins and the LC3-II/LC3-I ratio in rat renal tissues. This suggested that PNS treatment enhanced HIF-1α, which in turn increased autophagy. This was confirmed in transmission electron micrographs of renal tissues that showed autophagosomes in PNS-treated renal tissues. These findings demonstrate that PNS mitigates cisplatin-induced nephrotoxicity by enhancing mitophagy via a HIF-1α/BNIP3/Beclin-1 signaling pathway.

Raman tags: Novel optical probes for intracellular sensing and imaging.

Optical labels are needed for probing specific target molecules in complex biological systems. As a newly emerging category of tags for molecular imaging in live cells, the Raman label attracts much attention because of the rich information obtained from targeted and untargeted molecules by detecting molecular vibrations. Here, we list three types of Raman probes based on different mechanisms: Surface Enhanced Raman Scattering (SERS) probes, bioorthogonal Raman probes, and Resonance Raman (RR) probes. We review how these Raman probes work for detecting and imaging proteins, nucleic acids, lipids, and other biomolecules in vitro, within cells, or in vivo. We also summarize recent noteworthy studies, expound on the construction of every type of Raman probe and operating principle, sum up in tables typically targeting molecules for specific binding, and provide merits, drawbacks, and future prospects for the three Raman probes.

[Driving force analysis of land use change in the developed area based on Probit regression model: A case study of Nanjing City, China].

Based on the remote sensing image in 1996, 2002 and 2010, with the help of RS and GIS technology, and using the Probit regression model, this paper analyzed the characteristics of land use change in Nanjing City from 1996 to 2010, and the driving factors of land use change. The results showed that the cultivated land and woodland decreased, constructive land, garden plot and grassland continued to increase, and the comprehensive land use change rate was rising since 1996. The results of regression model for cultivated land and woodland change indicated that the change of cultivated land in the years 1996-2002 was mainly affected by the factors of "distance to the nearest rural settlement" and "farmers' population density". However, in the years 2002-2010 it was mainly affected by the factors of "change of per area GDP", "distance to the rural settlement" and "distance to the nearest road". The change of woodland in the years 1996-2002 was mainly affected by the factors of "the elevation" and "distance to the rural settlement". However, in the years 2002-2010 it was mainly affected by the factors of "change of per area GDP", "population density" and "distance to the nearest road". By comparison, the early driving factors of land use change were mainly natural factors, but in recent years, they were mainly social, economic and demographic factors.

Resonance Raman enhancement optimization in the visible range by selecting different excitation wavelengths.

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.