Similar Change Trend Research Articles

Changes in the flow regime of High Arctic catchments with different stages of glaciation, SW Spitsbergen

This study investigates the response of four High Arctic catchments with differing proportions of glacierization to changing climatic conditions. The study area located in SW Spitsbergen, has experienced a warming of 4.5 °C in the last 40 years along with a large increase in autumn rainfall. The changes in flow regime were determined based on available hydro-meteorological data and simulations of a semi-distributed rainfall-runoff model, which allowed reconstruction of streamflow in the period 1979–2020 and trend analyses for each calendar day. Similar trends of change were detected in all studied catchments. These include earlier onset of snowmelt driven floods (by two weeks over the period of analysis), large increases in autumn flows, prolongation of the hydrologically active season (starts earlier and lasts longer), decrease in flows in the latter half of June and the early part of August (except for the Breelva catchment). As a result of increases in autumn precipitation, the flood regime in these catchments has changed from snowmelt-dominated to the bi-modal with peaks in both July/August and September. The results also indicate differences in the magnitude of hydrological response depending on the percentage of glacial coverage in the catchments. The larger the glacierized area is, the larger the changes in the flow regime.The hydrological regime of SW Spitsbergen catchments has undergone dramatic changes over the last four decades. Such a shift in hydro-climatic conditions is larger than that observed in lower latitudes and has significant environmental implications.

Comparisons of Caustics and Strain Gauge Methods for Determining Mixed Mode Fracture Toughness of PMMA

Abstract Both caustics and the strain gauge methods are considered to be effective approaches to study material mixed mode fracture toughness. However, not many studies have recorded quantitative comparisons between these two methods. In this paper, three-point-bend tests are conducted using caustics and the strain gauge method simultaneously to determine the critical mixed mode stress intensity factors of polymethyl methacrylate (PMMA) specimens. The mixed mode fracture toughness is then derived by employing both methods for a thorough comparison and analysis. Besides, the J-integral method in ABAQUS simulation software is also employed for a further illustration of these two methods. According to the results, there is a similar changing trend in toughness calculated by caustics and the strain gauge method when there is an increase in a/b ratio (a is the crack length; b is the specimen width) of PMMA specimens. The differences in terms of mixed mode fracture toughness values between these two methods are quite narrow. Besides, in comparison to KIc, the variations of KIIc obtained by both methods are shown to change drastically as the a/b ratio of the specimen increases. Additionally, by analyzing and comparing these two methods, it is found that the caustic method is more sensitive when measuring the mixed mode fracture toughness, whereas the strain gauge method can satisfy a rough and quick need for calculating key fracture parameters.

MORPHOMETRICAL CHANGES IN THE RATS UTERUS THICKNESS AFTER 30 DAYS OF HEAVY METAL SALTS EXPOSURE

Introduction. Much attention is paid to the global ecological problem of environmental pollution with heavy metals (HM), starting from their production and use and ending with the search for means of their degassing and bioremediation. Particular attention is drawn to the study of the influence of HM on the reproductive system, in particular, the uterus. This is due to the high risk of reproductive ability deterioration and the reflection of the consequences of HM exposure in future generations. Objective. The objective of our study was to perform morphometric measurement of the structural elements of the uterine wall in female rats under the conditions of 30-day exposure to HM salts, as well as to study the protective role of vitamin E. Materials and Methods. For the experimental study, 24 female rats were selected and randomly divided into three series (8 rats in each): series I included control rats that received ordinary drinking water; series II included rats that daily consumed water saturated with HM salts; and series III included rats that were administered vitamin E orally every day against the background of constant consumption of water enriched with a combination of HM. After 30 days of the experiment, the uteri were removed; the sections were stained with hematoxylin and eosin for microscopic examination, followed by morphometric measurement of the structural elements and their statistical analysis. Results. First, we measured the morphometric dimensions of the structural elements of the uterine wall in the control animals. At the same time, in the animals of the experimental series II and III, the morphometric indicators underwent significant changes. Thus, on the 30th day of the study, series II rats showed a significant thickening of the uterine wall by 31.03% (p < 0.001) vs. the indicators of the control series. A similar trend of morphometric changes in the thickness of the uterus was noted in series III animals, where the uterus thickened by 20.58% (p < 0.001). Moreover, a significant difference was also observed between experimental series II and III. The analysis of the organ structural components in the experimental series indicated the predominance of endometrium thickness over myometrium thickness. Сonclusions. The results showed that 30-day exposure to HM led to a statistically significant thickening of the uterine wall. At the same time, the most pronounced changes in morphometric indicators were observed in the endometrium (in comparison with the myometrium and perimetrium) of both experimental models, both under the conditions of HM combination exposure and during the prophylactic use of vitamin E against the background of the action of xenobiotics. It is important to note that with the use of vitamin E, the morphometric indicators of the uterine thickness were characterized by a less pronounced transformation of values, although they still significantly exceeded the values of the control series.

Cognitive improvement effect of nervonic acid and essential fatty acids on rats ingesting Acer truncatum Bunge seed oil revealed by lipidomics approach.

Acer truncatum Bunge seed oil (ASO) is rich in ω-9 (53.93%) and ω-6 (30.7%) fatty acids (FAs) and characterized by 3-7% nervonic acid (NA, C24:1ω-9). Evidence suggests that ω-9 FAs such as NA participate in processes of cognitive improvement; however, their mechanism remains ambiguous. In this study, we investigated the effect of ASO on rat memory and the change in lipid profiling and underlying metabolism. After ASO was administrated to rats for one, three and seven days, their capacity for learning and memory significantly increased via the MWM test. Lipid profiling showed alterations in a wide range of metabolic features after ASO was administrated to the rats, in which sphingolipids (SP) in the serum and glycerophospholipids (GP) in the brain were regulated significantly. The changes in the fatty acids in the serum and brain showed the synergetic effects of NA, EA, OA and DHA, where NA, EA and OA exhibited similar change trends. The enrichment analysis based on KEGG indicated that ASO supplementation evoked the pathways of neurotrophin signaling, glycerophospholipid metabolism and sphingolipid metabolism, which are related to memory and cognition improvement. Among the metabolites with different molecular forms, the biomarkers with C24:1ω-9 chains exhibited a positive correlation with others both in the serum SP and brain GP. These results suggest the synergistic effects of ω-9 FAs and that their conversion into each other may result in enhanced cognition in rats ingesting Acer truncatum Bunge seed oil.

A highly accurate delta check method using deep learning for detection of sample mix-up in the clinical laboratory.

Delta check (DC) is widely used for detecting sample mix-up. Owing to the inadequate error detection and high false-positive rate, the implementation of DC in real-world settings is labor-intensive and rarely capable of absolute detection of sample mix-ups. The aim of the study was to develop a highly accurate DC method based on designed deep learning to detect sample mix-up. A total of 22 routine hematology test items were adopted for the study. The hematology test results, collected from two hospital laboratories, were independently divided into training, validation, and test sets. By selecting six mainstream algorithms, the Deep Belief Network (DBN) was able to learn error-free and artificially (intentionally) mixed sample results. The model's analytical performance was evaluated using training and test sets. The model's clinical validity was evaluated by comparing it with three well-recognized statistical methods. When the accuracy of our model in the training set reached 0.931 at the 22nd epoch, the corresponding accuracy in the validation set was equal to 0.922. The loss values for the training and validation sets showed a similar (change) trend over time. The accuracy in the test set was 0.931 and the area under the receiver operating characteristic curve was 0.977. DBN demonstrated better performance than the three comparator statistical methods. The accuracy of DBN and revised weighted delta check (RwCDI) was 0.931 and 0.909, respectively. DBN performed significantly better than RCV and EDC. Of all test items, the absolute difference of DC yielded higher accuracy than the relative difference for all methods. The findings indicate that input of a group of hematology test items provides more comprehensive information for the accurate detection of sample mix-up by machine learning (ML) when compared with a single test item input method. The DC method based on DBN demonstrated highly effective sample mix-up identification performance in real-world clinical settings.

Spatial-Temporal Features of Coordination Relationship between Regional Urbanization and Rail Transit-A Case Study of Beijing.

Urban rail transit is an important transportation infrastructure that mitigates the congestion of the central city and realizes compact city space development. However, the literature on the spatiotemporal coupling of urbanization and rail transit from the urban scale and its influencing factors is still uncommon. Taking Beijing as an example, based on the theory of coupling coordination, we have constructed a comprehensive indicator system for regional urbanization (hereafter RU) (including population, economy, and spatial urbanization) and rail transit (hereafter RT). On this basis, we use the entropy method, coupling coordination degree model, and spatial autocorrelation analysis method to explore the spatiotemporal characteristics of the overall and pairwise coupling coordination between population, economy, spatial urbanization, and rail transit. Finally, we analyze the spatial correlation and standard deviational ellipse analysis of the coupling coordination degree between RU and RT. The results indicate the following: (1) In addition to population urbanization, the other urbanization indicators and the RT level all show a downward–rising–falling trend from 2006 to 2017, among which the level of economic urbanization is the highest. The degree of coupling coordination between RU and RT is unbalanced development and shows a trend of first rising and then falling. (2) The degree of coupling coordination between RU and RT presents an imbalanced distribution in various regions, and the coupling coordination degree in the central urban areas is significantly higher than that in the outer suburbs. (3) From 2006 to 2017, the spatial correlation of the coupling coordination degree between the various systems has a similar changing trend. Moreover, the distribution of the spatial agglomeration points of the coupling coordination degree between RU and the RT is similar, showing a decreasing trend from the central urban area to the surrounding urban area. Therefore, relevant departments can rationally plan the construction of urban rail transit according to the coordination relationship between RU and RT and the spatial aggregation degree to realize the benign and sustainable development between urban especially suburbanization and rail transit.

The effect of an extended agricultural reclamation on changes in physical properties of technosols in post-lignite-mining areas: A case study from central Europe

Opencast mining destroys soils that have formed over many thousands of years. Their place is taken by post-mining areas such as external and internal dumps with materials whose physical and chemical properties are unfavorable from the point of view of plant growth and development. In order to minimize the negative effects of opencast mining, reclamation is necessary. In this work, we examined the impact of 42-year agricultural reclamation, in which three variants of mineral fertilization (0NPK, 1NPK, and 2NPK) were applied in the cultivation of alfalfa with the addition of orchard grass on changes in physical properties of Technosols. After forty-two years of agricultural reclamation, there has clearly been a differentiation of post-mining material into genetic horizons that differ in physical properties. The surface part of Technosols was converted to a humus-enriched surface horizon (Ap), which consisted of two subhorizons: Ap1 and Ap2, differing in structure, color, and consistency. In the 1978–2020 period in Ap1 of fertilized soils, there was a decrease in bulk density (BD, 9.0–10.9%) and particle density (PD, 1.5%), but an increase in structural stability index (SI, 243–337%), soil porosity (SP, 15.5–19.2%), air-filled porosity (AFP, 10.8–11.7%), field capacity (FC, 49–21.6%), plant available water capacity (PAWC, 46.4–48.0%) and S-index (46.9–50%). In the Ap2 subhorizon, there was a similar trend of changes; however, BD (for 2NPK), FC (for 1NPK), and PAWC (for 1NPK and 2NPK) were not significant. BD (5.4–14.3%) increased in most horizons of parent material (Cd) between 1978 and 2020, and SP (10.9–29%), AFP (16. 2–73.9%), and S-index values (9.4–34.4%) decreased. On the other hand, PD, SI, FC, and PAWC values did not change significantly.Cultivation o alfalfa with orchard grass in the 1978–2020 period significantly affected the profile variation in physical properties of Technosols, which was not observed when the field experiment was set up (1978). In the Ap horizon, DB and PD had significantly lower values, while SI, SP, AFP, FC, PAWC, and S had significantly higher values compared to parent materials (Cd). This is related to the indirect effect of soil organic carbon (SOC), which was beneficial to improving the surface horizon properties of developing Technosols. The diversity of physical properties of the 42-years old post-mining Technosols in the Ap was dependent on fertilization, especially in the Ap1 subhorizon. In fertilized Technosols, the BD and PD values were lower, and SP, DP, AFP, FC, PAWC, and S values were higher compared to unfertilized Technosols. Parent material (Cd) horizons after 42 years of reclamation had similar physical properties regardless of fertilization.

Differences of gut microbiota and lipid metabolism in Chinese perch ( Siniperca chuatsi ) with different growth rates

This study is aimed to explore the differences of gut microbiota and lipid metabolism in Chinese perch (Siniperca chuatsi) with different growth rates. After 180 days post-fertilization, among the population of Chinese perch (1,275 fish in total), 36 fish with different growth rates were selected from the low growth rate group (L group, initial weight 87 ± 2 g), the medium growth rate group (M group, initial weight 223 ± 4 g) and the high growth rate group (H group, initial weight 468 ± 13 g), respectively, with a total of 108 fish. The microbial species abundance and evenness in both M and H groups were obviously higher than those in the L group. The activities of lipase and trypsin in the gut showed a similar changing trend to the intestinal microbial diversity in L, M and H groups. The M and H groups showed a similar microbial composition, but they had different main functional bacteria. There were more microbial species in the H group than in the M group. Butyricicoccus might be used as an indicator to distinguish the growth rate of the M and H group. The intraperitoneal fat ratio and levels of triglyceride and total cholesterol in the plasma increased gradually with the increase in the growth rate. A large amount of fat accumulation was observed in the liver and gut of the H group, and the H group showed significantly higher levels of low-density lipoprotein and high-density lipoprotein in the plasma compared with the L and M groups. It was also found that the fat of the L and M groups mainly accumulated in the liver and gut, respectively, and the level of low-density lipoprotein in the plasma of the M group than that in the L group. The mRNA level of fas and srebp1 decreased gradually with the increase in the growth rate. The M and H group had high mRNA levels of pparα and cpt1 than the L group. The mRNA levels of lpl and hl were higher in the H group than those in the L and M groups.

The drivers of energy intensity changes in Chinese cities: A production-theoretical decomposition analysis

Quantifying the drivers of energy intensity change could provide valuable information for policy analysis and making. This study applied production-theoretical decomposition analysis to investigate the driving forces behind the energy intensity changes in Chinese cities between 2006 and 2017. The empirical results show that technological change and capital-energy substitutions were responsible for 6% and 4% of the fall in energy intensity on average, respectively, while technical efficiency contributed to about 2% of the increase in energy intensity, with significantly different magnitude across various cities. We further classified the sample cities based on the simultaneous effect of decomposition results, identifying the effective combinations of drivers on energy intensity reduction for different types of cities. The classification reveals that double-drivers and triple-drivers of energy intensity change prevail, which explains why energy intensity significantly fell in eastern and central regions but increased in the western region. Furthermore, the cities were categorized into four groups based on the differences in changes in energy intensity and energy efficiency. It reveals the key measures used to reduce energy intensity, and identifies that over a half of the cities with similar changing trends of energy intensity might be misjudged by policymakers with respect to energy efficiency performance.

Effects of escitalopram therapy on resting-state functional connectivity of subsystems of the default mode network in unmedicated patients with major depressive disorder

Antidepressants are often the first-line medications prescribed for patients with major depressive disorder (MDD). Given the critical role of the default mode network (DMN) in the physiopathology of MDD, the current study aimed to investigate the effects of antidepressants on the resting-state functional connectivity (rsFC) within and between the DMN subsystems. We collected resting-state functional magnetic resonance imaging (rs-fMRI) data from 36 unmedicated MDD patients at baseline and after escitalopram treatment for 12 weeks. The rs-fMRI data were also collected from 61 matched healthy controls at the time point with the same interval. Then, we decomposed the DMN into three subsystems based on a template from previous studies and computed the rsFC within and between the three subsystems. Finally, repeated measures analysis of covariance was conducted to identify the main effect of group and time and their interaction effect. We found that the significantly reduced within-subsystem rsFC in the DMN core subsystem in patients with MDD at baseline was increased after escitalopram treatment and became comparable with that in the healthy controls, whereas the reduced within-subsystem rsFC persisted in the DMN dorsal medial prefrontal cortex (dMPFC) and medial temporal subsystems in patients with MDD following escitalopram treatment. In addition, the reduced between-subsystem rsFC between the core and dMPFC subsystem showed a similar trend of change after treatment in patients with MDD. Moreover, our main results were confirmed using the DMN regions from another brain atlas. In the current study, we found different effects of escitalopram on the rsFC of the DMN subsystems. These findings deepened our understanding of the neuronal basis of antidepressants’ effect on brain function in patients with MDD. The trial name: appropriate technology study of MDD diagnosis and treatment based on objective indicators and measurement. URL: http://www.chictr.org.cn/showproj.aspx?proj=21377. Registration number: ChiCTR-OOC-17012566.

Study on dynamic properties of 1–3 cement-based piezoelectric composites

In this paper, Hopkinson compression bar technology is used to test the related properties of 1–3 cement-based piezoelectric composites under dynamic load. The research results prove that the stress and electric displacement of 1–3 cement-based piezoelectric composites have similar changing trends under dynamic action, that is, the response state of mechanical and electrical properties of the specimens is good. At the same time, due to the action of force, the phenomenon of electrical domain deflection and depolarization occurs, and the piezoelectric properties of the material also weaken with the increase of the number of loading.

Regulation of Phosphorus Supply on Nodulation and Nitrogen Fixation in Soybean Plants with Dual-Root Systems

Phosphorus (P) is an important nutrient affecting nodulation and nitrogen fixation in soybeans. To further investigate the relationship of phosphorus with soybean nodulation and nitrogen fixation, the seedling grafting technique was applied in this study to prepare dual-root soybean systems for a sand culture experiment. From the unfolded cotyledon stage to the initial flowering stage, one side of each dual-root soybean system was irrigated with nutrient solution containing 1 mg/L, 31 mg/L, or 61 mg/L of phosphorus (phosphorus-application side), and the other side was irrigated with a phosphorus-free nutrient solution (phosphorus-free side), to study the effect of local phosphorus supply on nodulation and nitrogen fixation in soybean. The results are described as follows: (1) Increasing the phosphorus supply increased the nodules weight, nitrogenase activity, ureide content, number of bacteroids, number of infected cells, and relative expression levels of nodule nitrogen fixation key genes (GmEXPB2, GmSPX5, nifH, nifD, nifK, GmALN1, GmACP1, GmUR5, GmPUR5, and GmHIUH5) in root nodules on the phosphorus-application side. Although the phosphorus-application and phosphorus-free sides demonstrated similar changing trends, the phosphorus-induced increases were more prominent on the phosphorus-application side, which indicated that phosphorus supply systematically regulates nodulation and nitrogen fixation in soybean. (2) When the level of phosphorus supply was increased from 1 mg/L to 31 mg/L, the increase on the P– side root was significant, and nodule phosphorus content increased by 57.14–85.71% and 68.75–75.00%, respectively; ARA and SNA were 218.64–383.33% and 11.41–16.11%, respectively, while ureide content was 118.18–156.44%. When the level of phosphorus supply was increased from 31mg/L to 61mg/L, the increase in the regulation ability of root and nodule phosphorus content, ARA, SNA, and ureide content were low for roots, and the value for nodules was lower than when the phosphorus level increased from 1 mg/L to 31 mg/L. (3) A high-concentration phosphorus supply on one side of a dual-root soybean plant significantly increased the phosphorus content in the aboveground tissues, as well as the roots and nodules on both sides. In the roots on the phosphorus-free side, the nodules were prioritized for receiving the phosphorus transported from the aboveground tissues to maintain their phosphorus content and functionality.

Comparative Study of Dynamic Stall between an Aircraft Airfoil and a Wind Turbine Airfoil in an Air–Particle Flow

Dynamic stall in clean air flow has been well studied, but its exploration in air–particle (air–raindrop or air–sand) flow is still lacking. The aerodynamic performance loss of aircraft (NACA0012) and wind turbine (S809) airfoils and their differences during the hysteresis loop at different pitching parameters are also poorly understood. As shown in this paper, the reduced frequency has little effect on the value of the maximum lift coefficient increment caused by particles, but a larger one can enhance the hysteresis effect and drag the angle of attack, at which the maximum increment is obtained, from the up stroke to the down stroke. The large lift coefficient increments of two airfoils and their difference also have a similar change trend with the reduced frequency. Compared to that of NACA0012 airfoil, the increments of S809 airfoil are obviously greater at three mean angles of attack, especially at 8°, which is the commonly used operating angle. In addition, the angle of attack, at which the maximum lift coefficient is obtained, can be significantly changed by particles in two regions: one is under the effect of deep stall, the other is under the effect of light stall at a low, reduced frequency.

Varves in the Yixian Formation, western Liaoning: Constraining the palaeoclimate in the Early Cretaceous

The study of the palaeoenvironment of the Early Cretaceous has been a significant research topic, largely due to the “Jehol Biota” in western Liaoning and the important prospect of fossils in Dakangpu Layer. Based on the sedimentology of Dakangpu Layer, it is helpful to get a deeper understanding of the living environment of the “Jehol Biota.” Varves are highly developed in the Dakangpu Bed of lower Cretaceous Yixian Basin in western Liaoning, China, supplying reliable and high‐quality proxies to explore the palaeoclimate. This paper reconstructs the palaeo‐lake environment and palaeoclimate, using petrography, facies associations, varves components, and geochemistry. Detailed petrographic studies helped to recognize 11 lithofacies which were grouped into two facies associations: Shallow lake and deep to semi‐deep lake sequences. The delicate structure of varves in the Dakangpu Bed were divided into two categories: Clastic and endogenic. Additionally, two sub‐types of clastic varves have been discovered, with distinct components, thickness, and distribution in vertical sequence. Nineteen representative samples of varves reveal that rare earth and trace elements have a similar change trend. The composition, formation, and preservation of the varves in the Dakangpu Bed depicted a deep lake, with stratified water and oxygen‐depleted bottom layer environment. The U/Th ratios and V/Cr ratios are in the ranges of 0.37–1.55 and 0.97–10.47 respectively, supporting the redox environment's minor fluctuation. The varve thickness, flood frequency, sporopollenin collections, and geochemical data indicated that precipitation and humidity decreased gradually in the sedimentary period, and the climate changed to warmer and drier, with fluctuations in the middle to later periods.

Characteristic identification of extracellular polymeric substances and sludge flocs affected by microalgae in microalgal-bacteria aggregates treating wastewater

The microalgal-bacterial aggregates (MABAs) treating wastewater have gained more attention. However, the introduce effect of microalgae on extracellular polymeric substances (EPS) and sludge flocs is not well clarified, which presents great impact on the operation stability of MABAs. This study selected the algae-based sequencing batch suspended biofilm reactor (A-SBSBR, Ra) as model to achieve both suspended (i.e., sludge phase) and fixed (i.e., biofilm phase) MABAs. Results showed that compared to control SBSBR, although the content of LB-EPS in suspended MABAs of Ra was reduced by 15.23%, the content of total EPS was increased by 4.54%, besides, both the types and contents of functional groups were enriched. Microalgal-bacteria biofilms (MABBs, i.e., fixed MABAs) showed similar change trends. In addition, sludge flocs in Ra presented better settleability and smaller particles, with the decrease rate of sludge volume index (SVI) and particle size of 14.76% and 9.17%. Morphology analysis proved that microalgae cells were mainly absorbed on LB-EPS layer. And this adhesion process made LB-EPS easier to fall off and form more soluble microbial products, with the increase rate of 16.67%. Moreover, oxygen produced by microalgae photosynthesis was favorable for enhancing the activity of bacteria, and then the production of EPSs was improved. It is expected that the characteristic identification of EPSs and variation evaluation of sludge flocs can provide some new insights for MABAs treating wastewater.

Ventilation and Pollutant Concentration for the Pedestrian Zone, the Near-Wall Zone, and the Canopy Layer at Urban Intersections.

To gain further insight into the ventilation at urban street intersections, this study conducted 3D simulations of the ventilation at right- and oblique-angled intersections under eight wind directions by using the Reynolds-averaged Navier–Stokes (RANS) -ε turbulence model. The divergent responses of ventilation and pollution concentration for the pedestrian zone (ped), the near-wall zone (nwz), and the canopy layer to the change in intersection typology and wind direction were investigated. The flow characteristics of the intersections, taken as the air flow hub, were explored by employing indices such as the minimum flow ratio (β) between horizontal openings. The results show that oblique wind directions lead to a lower total volumetric flow rate (Qtotal) but a higher β value for right-angled intersections. For T-shaped intersections, a larger cross-sectional area for the outflow helps to increase Qtotal. Oblique-angled intersections, for example, the X-shaped intersection, experience a more significant difference in Qtotal but a steady value of β when the wind direction changes. The vertical air-exchange rate for the intersection was particularly significant when the wind directions were parallel to the street orientation or when there was no opening in the inflow direction. The spatially averaged normalized pollutant concentration and age of air () for the pedestrian zone and the canopy layer showed similar changing trends for most of the cases, while in some cases, only the or changed obviously. These findings reveal the impact mechanism of intersection configuration on urban local ventilation and pollutant diffusion.

Inhibition of RAS components attenuates progression of heart failure and its adverse consequences on myocardial remodeling in both normotensive and hypertensive rats

Abstract Rationale and purpose Prevention or attenuation of heart failure (HF) is persistent task in clinic as well as challenge for progress in research. Both, intercellular connexin-43 (Cx43) channels and extracellular matrix (ECM) exert high impact on heart function. Thus, we aimed to explore whether HF due to volume overload (VO) induces alterations in myocardial Cx43, ECM proteins MMP2, SMAD2/3, TGFβ1 and PKC signaling as well as changes that may be revealed by enzyme histochemistry. Moreover, we tested the impact of treatment suppressing RAS on examined targeted proteins. Methods VO-HF was induced in male normotensive Hannover Sprague- Dawley (HSD) and mRen-2 transgenic hypertensive (TGR) rats by creating an aorto-caval fistula (ACF) and heart response was examined 20-weeks later. Sham-rats were compared with non-treated rats with ACF and those treated for 15-weeks with ACEI (trandolapril, 6mg/l, p.o.) or ARB (losartan (200mg/l, p.o.). Left ventricular heart (LV) tissue was analyzed using western blot, zymography and enzyme histochemistry. Key results Echocardiography confirmed an increase in cardiac output and a decrease in ejection fraction in both strains of rats. BW was higher in TGR vs HSD and it was not affected by VO. HW and LVW were higher in TGR vs HSD and VO increased both parameters regardless the strain while ACEI>ARB attenuated it. In parallel, myocardial pro-hypertrophic PKCd expression was higher in TGR vs HSD and increased in both strains due to VO while both drugs prevent it. Glycogen phosphorylase and capillary associated 5-nucleotidase, alkaline phospatase and dipeptidyl peptidase IV activities were reduced due to VO in HSD and TGR and it was attenuated by treatment. Cx43 expression and its functional phosphorylation status were lower in TGR vs HSD and suppressed in both strains due to VO but ACEI>ARB prevented it. Similar trend of changes was observed in PKCe expression, which phosphorylates Cx43. Profibrotic TGFβ1-Smad2/3 pathway was suppressed along with reduced MMP2 activity in TGR comparing to HSD. VO reduced SMAD2/3 in HSD and TGFβ1 in TGR as well as MMP2 expression in both strains, whereby treatment abolished these changes. VO decreased MMP2 (63kDa) activity only in TGR and ARB prevented it. VO did not affect collagen deposition in either strain vs sham rats. Conclusions Hypertrophic and hypofibrotic phenotypes are induced by volume overload in both rat strains. Together with deterioration of Cx43 mediated intercellular coupling it may contribute to heart dysfunction. Inhibition of RAS components attenuates progression of VO and its adverse consequences. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic VEGA 2/0158/19, 2/0002/20

Electroacupuncture in promoting neural repair after spinal cord injury: Inhibiting the Notch signaling pathway and regulating downstream proteins expression.

Spinal cord injury (SCI) is one of the serious central nervous system injuries and the incidence of SCI continues to increase. Previous studies have indicated that electroacupuncture (EA) is beneficial for promoting recovery after SCI. In the present study, we attempted to evaluate how EA can promote the neural repair in SCI model rats by observing changes in the Notch signaling pathway. Experimental rats were randomly divided into four groups. Each group had its own intervention period: 1 day, 7 days, 14 days, and 28 days, and five randomized subgroups: blank control (B) group, blank electroacupuncture (BE) group, sham operation (S) group, model control (M) group and EA group. Animals in the EA group and the BE group were treated with EA at Dazhui (GV14) and Mingmen (GV4) acupoints for 20 min. After the intervention period, the Basso-Beattie-Bresnahan (BBB) score was used to evaluate the neurological function. We found that BBB score increased in EA-treated groups. Hematoxylin and eosin staining was used to observe pathological changes in the injured spinal cord and the results showed that EA therapy could promote the repair of injured spinal cord tissue. Immunohistochemistry and Western blot methods were used to detect the expression of proteins Delta1, Presenilin1, Hes1, and Hes5 in the injured spinal cord. The results showed that the expression levels of Delta1, Presenilin1, Hes1, and Hes5 increased significantly after SCI and decreased after EA treatment. Our study suggested that the possible mechanism by which EA could benefit the recovery after SCI in rats may include inhibiting the Notch signaling pathway and regulating the downstream proteins expression. In addition, our study can provide reference for selecting acupoints and treatment cycle in the treatment of SCI.

Movement and acoustic radiation of a rising bubble from combustion of pyrotechnic mixtures using experiment and image processing method

Bubble volume and bubble geometry are key parameters that affect the movement and acoustic radiation performance of bubble columns. This paper proposes an image processing method to study the movement and acoustic radiation characteristics of the rising bubbles originating from the combustion of a pyrotechnic composition based on high-speed photography. Results showed that during the rise of bubbles, their shape gradually changed from spherical to irregular, and their rising trajectory presented a curvilinear form. After the rising velocities of the bubbles in the z and x directions were compared, the results revealed that the rising velocity of the bubbles was unstable. The velocity of the rising bubbles in the direction of the z axis was much higher than that of the x axis. Meanwhile, the acceleration of bubble volume decreased first and then increased. This process was repeated; however, the amplitude of increase or decrease was inconsistent, which led to the generation of a certain amount of acoustic radiation effect, and it had a similar trend of change with the acceleration of bubble volume.

Estimating fractional cover of non-photosynthetic vegetation for various grasslands based on CAI and DFI

Non-photosynthetic vegetation (NPV) is a vital component of terrestrial ecosystems and an important indicator of grassland degradation, therefore, it is of great significance to realize its accurate evaluation. Here, we analyzed spectral characteristics of NPV of different biomass types in undisturbed vegetation (herb, subshrub and shrub), and established relationship models among dead fuel index (DFI), cellulose absorption index (CAI) and fractional cover of NPV (fNPV) based on ground hyperspectral data; then, fNPV of four grassland types were evaluated based on the models. Our results showed that: (1) NPV reflectance exhibited similar change trends for herb, subshrub, shrub, and a mixed type, although there were significant differences among values, (2) DFI and CAI, CAI and fNPV, DFI and fNPV were significantly positively correlated (p < 0.001), (3) the maximum fNPV estimation accuracy of CAI was higher than that of DFI, and the values were 85 and 75%, respectively, (4) fNPV differed significantly among the four grasslands, with highest in meadow grassland (77%) and lowest in desert grassland (43%). We conclude that fNPV has obvious heterogeneity among different vegetation types, and both CAI and DFI can be used to reflect fNPV although there is difference in evaluation performance.