A human serum albumin-binding-based fluorescent probe for monitoring hydrogen sulfide and bioimaging.

In this work, a fluorescent probe, TPABF-HS, was developed for detecting hydrogen sulfide (H2S) using a human serum albumin (HSA)-binding-based approach for amplifying the fluorescence signal and extending the linear correlation range. Compared to the most recent probes for H2S, the most interesting feature of the detection system developed herein was the especially wide linear range (0-1000 µM (0-100 eq.)), which covered the physiological and pathological levels of H2S. TPABF-HS could be used in applications high sensitivity and selectivity with an LOD value of 0.42 µM. Further, site-competition experiments and molecular docking simulation experiments indicated that signal amplification was realized by the binding of the TPABF fluorophore to the naproxen-binding site of HSA. Moreover, the extension of the measurement span could allow for applications in living cells and Caenorhabditis elegans for imaging both exogenous and endogenous H2S. This work brings new information to the strategy of signal processing by exploiting fluorescent probes.

Multistage Filtration Desalination via Ion Self-Rejection Effect in Cation-Controlled Graphene Oxide Membrane under 1 Bar Operating Pressure.

By building a thin graphene oxide membrane with Na+ self-rejection ability, high permeability, and multistage filtration strategy, we obtained fresh water from a saline solution under 1 bar of operating pressure. After five and 11 cycles of the multistage filtration, the Na+ concentration decreased from 0.6 to 0.123 mol/L (below physiological concentration) and 0.015 mol/L (fresh water), respectively. In comparison with the performance of commercial reverse osmosis membranes, energy consumption was only 10% and water flux was higher by a factor of 10. Interestingly, the energy consumption of this multistage filtration strategy is close to the theoretical lowest energy consumption. Theoretical calculations showed that such Na+ self-rejection is attributed to the lower transportation rate of the Na+ than that of water within the graphene oxide membrane for the hydrated cation-π interaction. Our findings present a viable desalination strategy for graphene-based membranes and improve the mechanistic understanding of water/ion transportation behaviors in confined spaces.

Unexpected higher corrosion in the gas phase region of metals caused by calcium and magnesium ions compared to sodium ions.

In the marine environment, Na+ ions have been the focus of attention owing to their high content, which is one of the important factors causing marine corrosion. With reference to the content of macro ions in seawater, circular iron samples were semi-immersed in 0.04 M MgCl2 and 0.6 M NaCl solutions containing different proportions of ethanol. Unexpectedly, we observed more severe corrosion effects in the gas phase region and at the gas-liquid interface of metal samples semi-immersed in the MgCl2 solution. Although the concentration of the MgCl2 solution was only 1/15 of that of the NaCl solution, the iron corrosion induced by MgCl2 was significantly more severe than that caused by NaCl when the ethanol content was increased. Mg2+ ions outperform Na+ ions in metal gas phase corrosion. Especially in the oxygen content of the gas phase corrosion product, MgCl2 caused an increase by up to 52.7%, while NaCl only resulted in a 10.3% increase. Ethanol is normally regarded as a corrosion inhibitor and exists in the liquid phase. Interestingly, in the gas phase and at the gas-liquid interface, ethanol aggravated rather than reducing iron corrosion, particularly in the presence of Mg2+ ions. In addition, we observed that Ca2+ ions produced more severe corrosion effects.

Development of epimedin A complex drugs for treating the osteoporosis.

Osteoporosis is the most common disease involving bone degeneration. As the age of the population increases, the prevalence of the disease is expected to rise. However, current treatment methods do not provide a desirable solution for the restoration of the function of degenerated bones in patients with osteoporosis. This led to emergence of controlled delivery systems to increase drug bioavailability and efficacy specifically at the bone regeneration. In this study, an epimedin A (EA) complex drug system was prepared by solution blending method. In vitro cell-based experiments showed that the EA complex drug could significantly promote the differentiation and proliferation of osteoblasts and increase the alkaline phosphatase activity, calcium nodule formation, and the expression of osteogenesis-related genes and proteins. In vivo experiments further demonstrated that this novel drugs remarkably enhanced bone regeneration. These results suggest that EA may be used for the treatment of osteoporosis.

Characterization and pathogenicity of fowl adenovirus serotype 4 isolated from eastern China.

BACKGROUND: Fowl adenovirus outbreaks have occurred in China since June 2015. This virus is an emerging infectious disease that causes hydropericardium syndrome and inclusion body hepatitis (HPS-IBH), resulting in significant economic loss to poultry farmers. Five fowl adenovirus (FAdV) strains (HN, AQ, AH726, JS07 and AH712) were isolated from Jiangsu and Anhui provinces. RESULTS: Phylogenetic analysis revealed that the five isolates belonged to species C fowl adenovirus serotype 4. An 11 amino-acid deletion in ORF29, relative to an older viral isolate, JSJ13, was observed for all five strains described here. In chicken experiments, 80-100% birds died after intramuscular inoculation and displayed lesions characteristic of HPS-IBH. The viral DNA copies were further detected by hexon-probe based real-time polymerase chain reaction (PCR) in the chicken samples. The viral loads and cytokine profiles were recorded in all the organs after infections. Despite minor genetic differences, the 5 strains displayed significantly different tissue tropisms and cytokine profiles. CONCLUSIONS: Our data enhance the current understanding some of the factors involved in the pathogenicity and genetic diversity of the FAdV serotype 4 (FAdV-4) in China. Our work provides theoretical support for the prevention and control of HPS-IBH in chickens.

Debonding Damage Detection in CFRP Plate-Strengthened Steel Beam Using Electromechanical Impedance Technique.

Carbon fiber reinforced polymer materials are widely applied in structure strengthened engineering because of the many advantages of carbon fiber reinforced polymer. However, the debonding damage between the carbon fiber reinforced polymer and host structures occurs frequently, which might lead to the brittle failure of structure components, especially flexural ones. In this paper, an electromechanical impedance-based method, an important technique in structural health monitoring, was adopted to detect the debonding damage of carbon fiber reinforced polymer plate-strengthened steel beam by using lead zirconate titanate (PZT) transducers. A carbon fiber reinforced polymer plate-strengthened steel beam specimen was fabricated in the laboratory and two PZT sensors were attached at different locations on the carbon fiber reinforced polymer plate. The impedance signatures with variation of the different degrees of the debonding damage were measured by an impedance analyzer. The root-mean-square deviation method and the cross-correlation coefficient method were used to quantify the correlation between the electromechanical impedance and the debonding damage degree. The results reflect that an electromechanical impedance-based structural health monitoring technique can serve as a good method to detect the debonding damage of carbon fiber reinforced polymer plate-strengthened steel structures.

Prevention and treatment effect of total flavonoids in Stellera chamaejasme L. on nonalcoholic fatty liver in rats.

BACKGROUND: The incidence of nonalcoholic fatty liver disease (NAFLD) has been increasing worldwide in parallel with the obesity epidemic. This study aims to investigate the effects of the total flavonoids in Stellera chamaejasme L. (TFSC) on the experimental NAFLD in high fat diet fed (HFD) rats. METHODS: NAFLD model was induced in male Wistar rats by high-fat diet, and the rats in NAFLD group were randomized into NAFLD group (n = 20) and TFSC-treated group (n = 60). Both groups were given high-fat diet, and the normal group (n = 20) was given normal diet. In addition, the TFSC treated group was administered TFSC orally once a day at a low dose of 100 mg/kg (n = 20), medium dose of 200 mg/kg (n = 20), and high dose of 400 mg/kg (n = 20) for 6 weeks. Subsequently, the rats were sacrificed and body weight changes, lipid profiles in plasma and liver pathology were examined. The relative levels of fatty acid synthesis and ß-oxidation gene expression in hepatic tissues were measured by quantitative real-time polymerase chain reaction (RT-PCR). RESULTS: After the HFD administration for 4 weeks, the body weight,serum TC and TG levels in the rat of model group were significantly higher than in normal group (P < 0.05), and which Showed that the experimental NAFLD model was successfully established. While continual feeding with HFD deteriorated NAFLD and hyperlipidemia, and treatment with the different doses of TFSC effectively improved serum and liver lipid metabolism and liver function. A linear relationship between the dose of TFSC and blood lipid level was observed. The mRNA expression of hepatic acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), Leptin (LEP) and sterol regulatory element binding protein (SREBP)-1c as well as peroxisome proliferator-activated receptor (PPAR) -γ were significantly lower in high-dose group compared to the positive control group (P < 0.05). The hepatic mRNA expression of Cholesterol 7α-hydroxylase1 (CYP7A1), Carnitine palmitoyltransferase-1 (CPT1) and peroxisome proliferator-activated receptor (PPAR) -α were significantly higher in the high-dose group compared to the positive control group (P < 0.05). However, no difference was detected in the middle-dose group or the low-dose group compared to the positive control group (P > 0.05). CONCLUSION: TFSC treatment effectively improved NAFLD-related hyperlipidemia and inhibited liver steatosis in rats, and accompanied by modulating the expression of genes for regulating lipid metabolism.

Spatio-temporal distribution and evolution of the Tujia traditional settlements in China.

The rapid modernization in China has aggravated the reduction of the traditional settlements and aroused concern about the protection and research. This study aims to examine the spatial-temporal variations Tujia traditional settlements in China and to delineate the driving mechanism of the settlement distribution. Previous studies have focused on the characteristics of settlements in provincial or smaller areas, providing lacked information regarding spatial distribution heterogeneity of Tujia traditional settlements in China. In this study, the spatial heterogeneity and influence factors of the distribution of traditional Tujia settlements were examined using the GIS platform and statistical methods. The results reveal that the spatial distribution of settlements exhibits clustering with the pattern of "scattered distribution in a large region, while concentrated in small areas". The settlements were generally built in low hills, gentle slopes, sunny slopes and low-relief terrain areas, with elevation, relief degree of land surface (RDLS), slope and aspect were the key factors affecting the distribution. In Song, Yuan, Ming and Qing dynasties, settlements showed significant clustering all through, though the location and number of clustering center kept changing. In this process, the history of the Tujia chieftain and the transportation and marketing lines of Sichuan salt had a profound influence on the historical evolution of the settlement.

Spatial distribution characteristics and influencing factors of traditional villages based on geodetector: Jiarong Tibetan in Western Sichuan, China.

Jiarong Tibetan is a regional group with distinctive regional characteristics and possess precious traditional village resources. Studying the spatial distribution and influencing factors of traditional villages is of vital significance for the protection and renewal of villages and the revitalization of cultural heritage. Nevertheless, due to the fact that the Jiarong Tibetan inhabited area has not been clearly defined for a long time, there is a lack of holistic discussion on the distribution features and driving mechanisms of traditional villages in this region. In order to fill this research gap, the paper is the first to break away from the existing county administrative divisions to define the study area. Moreover, the analysis is carried out by using the nearest neighbor index, kernel density, GoeDa and Geodetector, etc. for traditional villages at national-level and provincial-level. The results show that the spatial distribution of the traditional villages of Jiarong Tibetan is characterized by typical aggregation, with the core intensive area in Danba County and the sub-core intensive area in the central and northern parts. The results of factor detection show that the spatial distribution pattern of the traditional villages is the consequence of the synergistic effect of multiple factors, and the interaction effect is significantly enhanced. The economic level and climatic conditions play a controlling role, and population, elevation, intangible cultural heritage and rivers also have notable effects. The findings of study can offer scientific guidance and suggestions for the inheritance and development of traditional villages in Jiarong Tibetan settlement area.

A structural optimized fluorescent probe for monitoring hydrogen sulfide in cells and zebrafish.

In this work, we reported a fluorescent probe Fur-SH, a derivative of benzofuranone, which was used to detect H2S in living cells and zebrafish. Based on the three structural characteristics of the probe, the effects of different structural modifications on the optical properties of the fluorophore were compared. Then, the fluorophore Fur-OH was synthesized by modifying diethylamino group with benzofuranone as the main skeleton. With 2,4-dinitrofluorobenzene as the recognition group and diethylamino as the electron donor, the push-pull electron effect occurred with nitro group, which led to fluorescence quenching, and an openable fluorescent probe Fur-SH was formed. The probe Fur-SH (λex = 510 nm; λem = 570 nm) had the advantages of smaller full width at half maxima, rapid response (5 min) and wide pH window. The quantitative properties of the probe were excellent, reaching saturation at 50 equivalents of substrate. The probe Fur-SH showed high sensitivity to H2S, with LOD of 48.9 nM and LOQ of 50 nM. At present, the probe Fur-SH had been applied to fluorescence imaging of MCF-7 cells and zebrafish. By comparing the effects of different structures on the optical properties of fluorophores, this work was expected to be helpful to the development of fluorescent probes in the future.

Different crystallographic Ni(OH)2 as highly efficient Fenton-like catalysts for sulfate radical activation.

By a simple hydrothermal method, a phase boundary between α- and ß-Ni(OH)2 can be obtained. The Fenton-like performance of α@ß-Ni(OH)2 is 1.56 times higher than that of single ß-Ni(OH). α@ß-Ni(OH)2 displays superior stability compared to α-Ni(OH)2, ß-Ni(OH)2, and amorphous Ni(OH)2, which makes significant contributions to developing advanced catalysts in diverse fields.

Unexpected iron corrosion by excess sodium in two-dimensional Na-Cl crystals of abnormal stoichiometries at ambient conditions.

At ambient conditions, we found salt crystals formed from unsaturated solutions on an iron surface; these salt crystals had abnormal stoichiometries (i.e. Na2Cl and Na3Cl), and these abnormal crystals with Cl:Na of 1/2-1/3 could enhance iron corrosion. Interestingly, we found that the ratio of abnormal crystals, Na2Cl or Na3Cl, with ordinary NaCl was relative to the initial NaCl concentration of the solution. Theoretical calculations suggest that this abnormal crystallisation behaviour is attributed to the different adsorption energy curves between Cl--iron and Na+-iron, which not only promotes Na+ and Cl- adsorbing on the metallic surface to crystallise at unsaturated concentration but also induces the formation of abnormal stoichiometries of Na-Cl crystals for different kinetic adsorptionprocess. These abnormal crystals could also be observed on other metallic surfaces, such as copper. Our findings will help elucidate some fundamental physical and chemical views, including metal corrosion, crystallisation and electrochemical reactions.

Analysis of the meteorological factors affecting the short-term increase in O3 concentrations in nine global cities during COVID-19.

Surface ozone (O3) is a major air pollutant around the world. This study investigated O3 concentrations in nine cities during the Coronavirus disease 2019 (COVID-19) lockdown phases. A statistical model, named Generalized Additive Model (GAM), was also developed to assess different meteorological factors, estimate daily O3 release during COVID-19 lockdown and determine the relationship between the two. We found that: (1) Daily O3 significantly increased in all selected cities during the COVID-19 lockdown, presenting relative increases from -5.7% (in São Paulo) to 58.9% (in Guangzhou), with respect to the average value for the same period in the previous five years. (2) In the GAM model, the adjusted coefficient of determination (R2) ranged from 0.48 (Sao Paulo) to 0.84 (Rome), and it captured 51-85% of daily O3 variations. (3) Analyzing the expected O3 concentrations during the lockdown, using GAM fed by meteorological data, showed that O3 anomalies were dominantly controlled by meteorology. (4) The relevance of different meteorological variables depended on the cities. The positive O3 anomalies in Beijing, Wuhan, Guangzhou, and Delhi were mostly associated with low relative humidity and elevated maximum temperature. Low wind speed, elevated maximum temperature, and low relative humidity were the leading meteorological factors for O3 anomalies in London, Paris, and Rome. The two other cities had different leading factor combinations.

Graphitic-like Hexagonal Phase of Alkali Halides in Quasi-Two-Dimensional Confined Space under Ambient Conditions.

The discovery of specific matter phases with abnormal physical properties in low-dimensional systems and/or on particular substrates, such as the hexagonal phase of ice and two-dimensional (2D) CaCl with an abnormal valence state, continuously reveals more fundamental mechanisms of the nature. Alkali halides, represented by NaCl, are one of the most common compounds and usually thought to be well-understood. In the past decades, many theoretical studies suggested the existence of one particular phase, that is, the graphitic-like hexagonal phase of alkali halides at high pressure or in low-dimension states, with the expectation of improved properties of this matter phase but lacking experimental evidence due to severe technical challenges. Here, by optimized cryo-electron microscopy, we report the direct atomic-resolution observation and in situ characterization of the prevalent and stable graphitic-like alkali halide hexagonal phases, which were spontaneously formed by unsaturated NaCl and LiCl solution, respectively, in the quasi-2D confined space between reduced graphene oxide layers under ambient conditions. Combined with a control experiment, density functional theory calculations, and previous theoretical studies, we believe that a delicate balance among the cation-π interaction of the solute and substrate, electrostatic interactions of anions and cations, solute-solvent interactions, and thermodynamics under confinement synergistically results in the formation of such hexagonal crystalline phases. These findings highlight the effects of the substrate and the confined space on the formation of specific matter phases and provide a universal scheme for the preparation of special graphitic-like hexagonal phases of alkali halides.

Characterization of Co-infection With Fowl Adenovirus Serotype 4 and 8a.

Fowl adenoviruses (FAdVs), which are distributed worldwide, have caused considerable economic losses to poultry farms. Co-infection with FAdVs and other avian pathogens has been reported previously. However, the pathogenicity of different serotypes of FAdVs causing co-infection remains unclear. Herein, strain HN from FAdV species C serotype 4 (FAdV-4) and strain AH720 from species E serotype 8a (FAdV-8a) were used to assess the pathogenicity of their co-infection in specific-pathogen-free (SPF) chickens. Compared with chickens infected with FAdV-4 alone, those co-infected with FAdV-4 and FAdV-8a showed similar clinical symptoms, mortality rates and degree of tissue lesions, and notably decreased viral loads of HN. Conversely, the viral loads of AH720 increased markedly in the co-infection group compared with that in chickens infected with AH720 strain alone. Increased viral loads of AH720 in the liver were suspected to contribute to the pathogenicity of chickens co-infected with the HN and AH720 strains. This was further investigated by histopathology and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining analyses. Collectively, these data indicated that co-infection with FAdV-4 and FAdV-8a suppresses the replication and proliferation of FAdV-4 but enhances the replication and proliferation of FAdV-8a in chicken liver. This study will provide valuable information for the further investigation of the interactions between FAdV-4 and FAdV-8a during co-infection.

Subspace mixed rational time-frequency multiwindow Gabor frames and their Gabor duals.

For a usual multiwindow Gabor system, all windows share common time-frequency shifts. A mixed multiwindow Gabor system is one of its generalizations, for which time-frequency shifts vary with the windows. This paper addresses subspace mixed multiwindow Gabor systems with rational time-frequency product lattices. It is a continuation of (Li and Zhang in Abstr. Appl. Anal. 2013:357242, 2013; Zhang and Li in J. Korean Math. Soc. 51:897-918, 2014). In (Li and Zhang in Abstr. Appl. Anal. 2013:357242, 2013) we dealt with discrete subspace mixed Gabor systems and in (Zhang and Li in J. Korean Math. Soc. 51:897-918, 2014) with L 2 ( R ) ones. In this paper, using a suitable Zak transform matrix method, we characterize subspace mixed multiwindow Gabor frames and their Gabor duals, obtain explicit expressions of Gabor duals, and characterize the uniqueness of Gabor duals. We also provide some examples, which show that there exist significant differences between mixed multiwindow Gabor frames and usual multiwindow Gabor frames.

A time domain characterization of vector-valued subspace weak Gabor bi-frames.

The construction of bi-frames is a fundamental problem in frame theory. Due to their wide applications, the study of vector-valued frames and subspace frames has interested many mathematicians in recent years. In this paper, we introduce the weak Gabor bi-frame (WGBF) in vector-valued subspaces, characterize WGBFs on the time domain, and present some examples.

Some new inequalities for continuous fusion frames and fusion pairs.

This paper addresses continuous fusion frames and fusion pairs which are extensions of discrete fusion frames and continuous frames. The study of equalities and inequalities for various frames has seen great achievements. In this paper, using operator methods we establish some new inequalities for continuous fusion frames and fusion pairs. Our results extend and improve ones obtained by Balan, Casazza and Gavruta.

[Isolation, culture and differentiation of skeletal muscle satellite cells of Luxi cattle embryo].

OBJECTIVE: To isolate and culture skeletal muscle satellite cells of Luxi cattle embryo and study its biological characteristics. METHODS: The skeletal muscles were taken from the limbs of Luxi cattle embryo of 30-50 d old to isolate and culture the skeletal muscle satellite cells by differential adherence method and co-digestion of type I collagenase and trypsin. Satellite cell surface markers, desmin, MyoD, c-Met, Myf5 and pax7 were detected by immunocytochemistry and RT-PCR, and its biological characteristics were researched. RESULTS: The satellite cells were cultured to over passage 15. Cell viability was (97.90 ± 0.96)% after cryopreservation. The immunocytochemical staining showed that the specific surface antigen markers desmin and MyoD were positive, and RT-PCR also indicated the positive expressions of desmin, Myf5, c-Met and pax7. Colony formation was (56.39 ± 1.41)%. The karyotype analysis demonstrated that the isolated satellite cells were all derived from normal cattle embryos. Bovine satellite cells were successfully induced into osteoblasts and neuron-like cells by various inductors, and were positively expressed after alizarin red and toluidine blue staining. The osteoblast specific genes osteopontin and type I collagen and the nerve cell specific genes MAP-2 and nestin were positive by RT-PCR. CONCLUSION: The skeletal muscle satellite cells of the Luxi cattle embryo are successfully isolated and cultured in vitro , They have the ability of being differentiated into osteoblasts and neuron-like cells.