High-Pressure Synthesis, Crystal Structure, and Physical Properties of a Spinel Compound Co0.7Al2S4.

In this paper, we report on the discovery of a spinel compound, Co0.7Al2S4, which was synthesized at high-pressure. The systematic characterizations were carried out by structural, magnetic, and heat capacity measurements. The compound crystallizes into a cubic structure with the space group Fd3̅m (no. 227) and the lattice constant a = 9.9580(1) Å. Magnetic susceptibility measurements suggest that Co0.7Al2S4 exhibits a spin glass ground state, freezing at Tf ∼ 7.2 K with a Weiss temperature Tθ ∼ -115.9 K, which is verified by ac magnetic susceptibility and heat capacity measurements. The frustration parameter f for Co0.7Al2S4 is calculated to be about 16.6, based on the formula f = | Tθ/Tf |, indicating that Co0.7Al2S4 is a high-frustration magnet. Specific heat data displays a T2 dependence below the freezing temperature, which is different from the linear dependence observed in a common spin glass system. Compared with the similar compound CoAl2O4, it is suggested that the vacancies in the Co sites should be responsible for the occurrence of the spin glass behavior of Co0.7Al2S4.

Long-term analysis of the urban heat island effect using multisource Landsat images considering inter-class differences in land surface temperature products.

It is imperative to quantitatively analyze the long-term temporal and spatial characteristics of the urban heat island (UHI) effect on cities for applications, such as urban expansion and environmental protection. Owing to the high spatial resolution and availability of long time-series data, remote sensing images from Landsat satellites are widely used for land surface temperature (LST) retrieval. However, limited by the satellite revisit cycle and image quality, the use of multisource Landsat images in a long-term study of the UHI effect is inevitable. Nonetheless, owing to the differences among multisource sensors, such as Landsat-7 and Landsat-8, there may be apparent deviations in the LST results retrieved from different sensor data, which are obtained from the same area and under similar circumstances. Consequently, it is necessary to build a relationship between the LST results generated from multisource Landsat sensors for future research on the UHI effect. In this study, Shenzhen city was studied to explore the fitting relationship between the corresponding LST products from Landsat-7 and Landsat-8 images obtained from adjacent dates with similar climatic conditions. Furthermore, factors affecting the fitting models, such as land cover types, seasonal and inter-annual differences, were analyzed. The constructed fitting model had a strong relationship with land cover types but a relatively weak relationship with seasonal and inter-annual differences; this indicates that a pseudo Landsat-8-based LST product can be generated from a Landsat-7-based LST product using a model fitted by a Landsat-7/8 pair obtained from adjacent years (or different seasons). Finally, by considering the consistency between LST products from multisource Landsat images, the spatiotemporal variations in the UHI effect in Shenzhen can be accurately explored using long time-series data.

Pingyang Jiangya Fang pretreatment reduces the blood pressure of spontaneously hypertensive rats with Liver-Yang hyperactivity syndrome via ROS/Akt oxidative stress pathway.

BACKGROUND: ROS/Akt pathway oxidative stress refers to a procedural response that activates various stress-sensitive signaling pathways in the cell thereby inducing insulin resistance (IR), and is closely related to high blood pressure. This study aims to investigate the effects of Pingyang Jiangya Fang (PYJYF) on the ROS/Akt pathway oxidative stress response in spontaneously hypertensive rats (SHRs) with Liver-Yang hyperactivity syndrome. METHODS: Except for the Wistar-Kyoto (WKY) and SHR groups, the other groups' rats were administered with Fuzi Decoction, to duplicated the model of hyperactivity of Liver-Yang. These rat's scleral color of deepens and become red, and rat's degree of irritability reached to above II degree. Compared with control group, rat's water consumption increased significantly, rotation tolerance time reduced significantly, pain threshold reduced significantly, rat tail vein systolic blood pressure (SBP) increased significantly. It shows that the model rats with hyperactivity of Liver-Yang have successfully replicated. Then, the corresponding drugs in the positive medicine group (candesartan cilexetil tablets) and the high, middle, and low dose groups of PYJYF (PYJYF-H, PYJYF-M, PYJYF-L) were administered. This work detected and analyzed behavior, SBP, renin-angiotensin system (RASS), expression of skeletal muscle angiotensin II type 1 receptor/angiotensin II type 2 receptor (AT1R/AT2R), IR index, renal/renal vascular/skeletal muscle tissue damage in each group. Moreover, we identified the target effect of point composition in the ROS/Akt signaling pathway. RESULTS: Unlike the WKY and SHR groups, the model group exhibited the phenotype of Liver-Yang hyperactivity syndrome, markedly increased SBP, hyper-RASS system, increased urine N-acetyl-ß-Dglucosidase (NAG) and microalbuminuria (m-ALB), increased AT1R/AT2R ratio of skeletal muscle, IR, concomitant renal and skeletal muscle damage, as well as significant upregulation in the expression of ROS/ Akt signaling factor. PYJYF-H and PYJYF-M improved Liver-Yang hyperactivity syndrome, reduced SBP, the RASS system, urine NAG and m-ALB, AT1R/AT2R ratio, IR index, repair renal, renal vascular, and skeletal muscle tissue injury, as well as downregulated the expression of ROS/Akt signal factor. CONCLUSIONS: PYJYF reduces blood pressure by inhibiting ROS/Akt pathway oxidative stress and reducing IR.

Spatiotemporal spread pattern of the COVID-19 cases in China.

The COVID-19 pandemic is currently spreading widely around the world, causing huge threats to public safety and global society. This study analyzes the spatiotemporal pattern of the COVID-19 pandemic in China, reveals China's epicenters of the pandemic through spatial clustering, and delineates the substantial effect of distance to Wuhan on the pandemic spread. The results show that the daily new COVID-19 cases mostly occurred in and around Wuhan before March 6, and then moved to the Grand Bay Area (Shenzhen, Hong Kong and Macau). The total COVID-19 cases in China were mainly distributed in the east of the Huhuanyong Line, where the epicenters accounted for more than 60% of the country's total in/on 24 January and 7 February, half in/on 31 January, and more than 70% from 14 February. The total cases finally stabilized at approximately 84,000, and the inflection point for Wuhan was on 14 February, one week later than those of Hubei (outside Wuhan) and China (outside Hubei). The generalized additive model-based analysis shows that population density and distance to provincial cities were significantly associated with the total number of the cases, while distances to prefecture cities and intercity traffic stations, and population inflow from Wuhan after 24 January, had no strong relationships with the total number of cases. The results and findings should provide valuable insights for understanding the changes in the COVID-19 transmission as well as implications for controlling the global COVID-19 pandemic spread.

SCRMS: An RFID and Sensor Web-Enabled Smart Cultural Relics Management System.

Cultural relics represent national or even global resources of inestimable value. How to efficiently manage and preserve these cultural relics is a vitally important issue. To achieve this goal, this study proposed, designed, and implemented an RFID and Sensor Web-enabled smart cultural relics management system (SCRMS). In this system, active photovoltaic subtle energy-powered Radio Frequency Identification (RFID) is used for long-range contactless identification and lifecycle management of cultural relics during their storage and circulation. In addition, different types of ambient sensors are integrated with the RFID tags and deployed around cultural relics to monitor their environmental parameters, helping to ensure that they remain in good condition. An Android-based smart mobile application, as middleware, is used in collaboration with RFID readers to collect information and provide convenient management for the circulation of cultural relics. Moreover, multiple sensing techniques are taken advantage of simultaneously for preservation of cultural relics. The proposed system was successfully applied to a museum in the Yongding District, Fujian Province, China, demonstrating its feasibility and advantages for smart and efficient management and preservation of cultural relics.

Cyber-physical geographical information service-enabled control of diverse in-situ sensors.

Realization of open online control of diverse in-situ sensors is a challenge. This paper proposes a Cyber-Physical Geographical Information Service-enabled method for control of diverse in-situ sensors, based on location-based instant sensing of sensors, which provides closed-loop feedbacks. The method adopts the concepts and technologies of newly developed cyber-physical systems (CPSs) to combine control with sensing, communication, and computation, takes advantage of geographical information service such as services provided by the Tianditu which is a basic geographic information service platform in China and Sensor Web services to establish geo-sensor applications, and builds well-designed human-machine interfaces (HMIs) to support online and open interactions between human beings and physical sensors through cyberspace. The method was tested with experiments carried out in two geographically distributed scientific experimental fields, Baoxie Sensor Web Experimental Field in Wuhan city and Yemaomian Landslide Monitoring Station in Three Gorges, with three typical sensors chosen as representatives using the prototype system Geospatial Sensor Web Common Service Platform. The results show that the proposed method is an open, online, closed-loop means of control.

[Effect of Dahuang Zhechong pills on arterial thrombosis in rabbits].

OBJECTIVE: To investigate the effect of Dahuang Zhechong pills (DZ) on arterial thrombotic model in vivo. METHODS: Sixty-five rabbits were randomly divided into 7 groups: normal, model (collagen encapsulated thread-drawing),model+aspirin (ASA), model+clopidogrel (CP),model+ASA+CP, model+ low dosage DZ (DZL), and model+high dosage DZ (DZH). All rabbits except the normal group were fed with the drugs repectively for 8 days,and sacrificed at 2 hours after the last feeding, obtained aortae. The pathological changes in the aortae were observed under microscope,and the level of FDP, D-dimer and tissue factor (TF) were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: The vascular vessels were filled with thrombi in the model group and the elastic membranes of the vessel wall were seriously injured. The arterial thrombi were observed around the vascular wall in the DZL group, but some of the thrombi were dissolved. The number of thrombi was remarkably decreased in the DZH group, and most thrombi were dissolved and the vascular intimal membranes were intact. Compared with the model group, the dry and wet weight of the thrombi and the level of D-dimer, FDP, and TF in the plasma were significantly attenuated (P<0.01) in all the treatment groups. There were no significant difference between the DZL group and the ASA group in the dry weight, D-Dimer, and FDP (P>0.05). The pathological changes in the vascular vessel and the elevation of plasma parameters in the DZL group were similar to those in the ASA and CP groups (P>0.05). The dry and wet weight, D-dimer, FDP, and TF in the plasma in the DZH group were significantly lower than those in the DZL group (P<0.01 or P<0.05, separatively), and closed to those in the ASA+CP group. CONCLUSION: Dahuang Zhechong pills are potential novel anti-thromobotic agent for arterial thrombosis.

[Establishment and evaluation of a rabbit model of arterial thrombosis by collagen encapsulated thread-drawing].

OBJECTIVE: To establish and evaluate a rabbit model of arterial thrombosis by modified thread-drawing. METHODS: Fifty-three rabbits were randomly divided into 6 groups: a normal group, a ligating group,a collagen encapsulated thread-drawing group,a aspirin group,a clopidogrel group, and an aspirin clopidogral group. The endovascular pathological changes in the rabbits were observed, and D-fructose-1,6-diphosphate trisodium salt octahydrate (FDP), D-Dimer and tissue factor (TF) were detected with enzyme linked immunosorbent assay. RESULTS: In the thread-drawing group, thrombus was obvious, and the endovascular elastic membrane was injured seriously compared with the ligating group. After being treated with aspirin and clopidogrel, most arterial thrombus was softened, dissolved and absorbed. Compared with that in the modified thread-drawing group,wet and dry weight of thrombus increased,and the level of D-Dimer, FDP and TF also increased in the modified thread-drawing group (P<0.01). After being treated by aspirin and/or clopidogrel, the wet and dry weight of thrombus and the level of D-Dimer, FDP and TF decreased compared with the control (P<0.01). Aspirin plus clopidogral could obviously reduce the wet and dry weight of thrombus, and reduce the level of D-Dimer and FDP (P<0.01). Aspirin plus clopidogral could obviously inhibit the formation of TF compared with aspirin (P<0.05). CONCLUSION: Arterial thrombosis model by collagen encapsulated thread-drawing which is visible, repeatable and effective is better than thread-drawing. It is suitable for screening anti-thrombosis drugs and evaluating their effect.

[Raman studies of nanocrystalline BaTiO3 ceramics].

High pressure can significantly increase the densification. Further, during the high pressure assisted sintering, the nucleation rate is increased due to reduced energy barrier and the growth rate is suppressed due to the decreased diffusivity. Thus high pressure enables the specimen to be fabricated with relatively lower temperature and shorter sintering period that assures to obtain dense nanocrystalline ceramics. Dense nanocrystalline BaTiO3 ceramics with uniform grain sizes of 60 and 30 nm, respectively, were obtained by pressure assisted sintering. The crystal structure and phase transitions were investigated by Raman scattering at temperatures ranging from -190 to 200 degrees C. The Raman results indicated that the evolution of Raman spectrum with grain size is characterized by an intensity decrease, a broadening of the line width, a frequency shift, and the disappearance of the Raman mode. With increasing temperature, similar to 3 mm BaTiO3 normal ceramics, the successive phase transitions from rhombohedral to orthorhombic, orthorhombic to tetragonal, and tetragonal to cubic were also observed in nanocrystalline BaTiO3 ceramics. In addition, when particle size is reduced to the nanoscale, one will find some unusual physical properties in nanocrystalline ceramics, compared with those of coarse-grained BaTiO3 ceramics. The different coexistences of multiphase were found at different temperature. Especially, the ferroelectric tetragonal and orthorhombic phase can coexist at room temperature in nanocrystalline BaTiO3 ceramics. The phenomenon can be explained by the internal stress. The coexistences of different ferroelectric phases at room temperature indicate that the critical grain size for the disappearance of ferroelectricity in nanocrystalline BaTiO3 ceramics fabricated by pressure assisted sintering is below 30 nm.