Search Results (53)

The mechanisms of vascular tone regulation during early postnatal ontogenesis differ considerably from those in adulthood. We tested the hypothesis that the vasomotor influence of superoxide dismutases is higher in arteries of rats shortly after birth compared to adult animals. Saphenous arteries of 10 to 15 day (“young”) and 3 to 4 month (“adult”) old rats were studied using quantitative PCR, spectrophotometry, Western blotting, and isometric myography. Sod3 mRNA was most abundant in both adult and young saphenous arteries. Total SOD activity, Cu/ZnSODs activity, and SOD3 protein content were higher in young compared to adult arteries. H₂O₂ caused vessel contraction, while elimination of H₂O₂ weakened contractile responses of endothelium-denuded young arteries. The Cu/ZnSOD inhibitor DETC had no influence on contraction of adult arteries, but weakened contraction of endothelium-denuded, but not endothelium-intact arteries of young rats. The latter effect was observed in the presence of the NO-synthase inhibitor L-NNA, but not with the soluble guanylate cyclase inhibitor ODQ. DETC had no effect in the presence of sodium nitroprusside. Thus, Cu/ZnSODs promote contraction of saphenous arteries in the early postnatal period, but not in adult age. This influence of Cu/ZnSODs is counteracted by endothelial NO in early postnatal arteries. Full article

Background: Hypertension is a leading cause of cardiovascular morbidity and mortality. Taxifolin has shown cardiovascular benefits, but its antihypertensive mechanisms remain poorly defined. This study aimed to comprehensively elucidate the molecular mechanisms underlying Taxifolin’s blood pressure-lowering effects by integrating network pharmacology, molecular docking, ex vivo functional studies, and in vivo validation. Methods: Network pharmacology and molecular docking prioritized targets. Ex vivo thoracic aortas were obtained from healthy male Sprague–Dawley (SD) rats, and rings (3–4 mm) were prepared for vasorelaxation studies. Pathway-specific inhibitors, Western blotting, and ELISA were used to investigate mechanisms. In vivo, spontaneously hypertensive rats (SHRs) received oral Taxifolin 15, 30, or 60 mg/kg once daily for 28 days; propranolol (80 mg/kg) served as the positive control. Results: Taxifolin produced robust vasorelaxation in endothelium-intact rings (Rmax ≈ 121%), falling to ~72% after denudation. Relaxation was attenuated by LY294002, ODQ, indomethacin, and glibenclamide. In SHR aorta, Taxifolin increased NO by ~132% and cGMP by ~1.9-fold and upregulated p-Akt and eNOS; LY294002 abolished these effects. In vivo, Taxifolin reduced systolic blood pressure by ≈60 mmHg without adverse changes in hematology, biochemistry, or body weight. Conclusions: Taxifolin lowers blood pressure through multiple vascular mechanisms consistent with PI3K/Akt/eNOS, NO–sGC–cGMP, COX-2/PGI₂ and calcium-handling pathways, supporting its potential as a safe antihypertensive candidate. Full article

Xylosalsola chiwensis (Popov) Akhani & Roalson is listed in the Red Data Book of Kazakhstan as a rare species with a limited distribution, occurring in small populations in Kazakhstan, Uzbekistan, and Turkmenistan. The aim of this study is to deepen the understanding of the ecological conditions of its habitats, the floristic composition of its associated plant communities, the species’ morphological and anatomical characteristics, and its molecular phylogeny, as well as to identify the main threats to its survival. The ecological conditions of the X. chiwensis habitats include coastal sandy plains and the slopes of chinks and denudation plains with gray–brown desert soils and bozyngens on the Mangyshlak Peninsula and the Ustyurt Plateau at altitudes ranging from −3 to 270 m above sea level. The species is capable of surviving in arid conditions (less than 100 mm of annual precipitation) and under extreme temperatures (air temperatures exceeding 45 °C and soil surface temperatures above 65 °C). In X. chiwensis communities, we recorded 53 species of vascular plants. Anthropogenic factors associated with livestock grazing, industrial disturbances, and off-road vehicle traffic along an unregulated network of dirt roads have been identified as contributing to population decline and the potential extinction of the species under conditions of unsustainable land use. The morphometric traits of X. chiwensis could be used for taxonomic analysis and for identifying diagnostic morphological characteristics to distinguish between species of Xylosalsola. The most taxonomically valuable characteristics include the fruit diameter (with wings) and the cone-shaped structure length, as they differ consistently between species and exhibit relatively low variability. Anatomical adaptations to arid conditions were observed, including a well-developed hypodermis, which is indicative of a water-conserving strategy. The moderate photosynthetic activity, reflected by a thinner palisade mesophyll layer, may be associated with reduced photosynthetic intensity, which is compensated for through structural mechanisms for water conservation. The flow cytometry analysis revealed a genome size of 2.483 ± 0.191 pg (2n/4x = 18), and the phylogenetic analysis confirmed the placement of X. chiwensis within the tribe Salsoleae of the subfamily Salsoloideae, supporting its taxonomic distinctness. To support the conservation of this rare species, measures are proposed to expand the area of the Ustyurt Nature Reserve through the establishment of cluster sites. Full article

As an important target for deep marine shale gas exploration, shale reservoirs near denudation areas have enormous resource potential. Based on the impression method, the sedimentary paleogeomorphology near the denudation area is identified as three units: the first terrace, the second terrace, and the third terrace. At the second terrace where Well Z212 is located, the thickness of the Longmaxi Formation first section is only 0.8 m, and the continuous thickness of the target interval is only 4.3 m, making it a typical thin shale reservoir. By integrating petrology, mineralogy and the seismic method, the thin shale reservoir is characterized. Compared to shale reservoirs far away from the denudation area, the Well Z212 (near denudation area) production interval (Wufeng Formation first section) has high porosity (6%–10%), moderate TOC (3%–4%), a high carbonate mineral content (10%–35%), and a high gas content (>7 m³/t). The correlation between the total porosity of shale and the density of high-frequency laminations is the strongest, indicating that the silt laminations have a positive effect on pore preservation. There is a significant positive correlation between carbonate content and the volume of mesopores and macropores, as well as the porosity of inorganic pores. It is suggested that carbonate minerals are the main carrier of inorganic pores in Well Z212, and the pores are mainly composed of mesopores and macropores. Under the condition of being far away from the fault zone, even near the denudation area, it has good shale gas preservation characteristics. The key development technologies consist of integrated geo-steering technology, acidification, and volume fracking technology. Based on geological characteristics, the fracturing process optimization of Well Z212 has achieved shale reservoir stimulation. Full article

Although chloroquine appears to inhibit the alpha-1 adrenoceptor, whether the chloroquine-mediated inhibition of phenylephrine-induced contraction is associated with the blockade of alpha-1 adrenoceptors remains unknown. This study examined the effect of chloroquine on contractions elicited by the alpha-1 adrenoceptor agonist phenylephrine in isolated rat aortas and determined the underlying mechanism. The effects of chloroquine and the alpha-1 adrenoceptor inhibitor prazosin on phenylephrine-elicited contractions were examined. The effects of the irreversible alpha-adrenoceptor inhibitor phenoxybenzamine followed by washout with fresh Krebs solution, as well as combined treatment with chloroquine and phenoxybenzamine followed by washout with fresh Krebs solution, on phenylephrine-induced contraction were investigated. Chloroquine and prazosin inhibited phenylephrine-induced contractions. However, pretreatment with prazosin eliminated the chloroquine-induced inhibition of contractions elicited by phenylephrine. Additionally, pretreatment with chloroquine and phenoxybenzamine followed by washout produced a higher contraction elicited by phenylephrine than pretreatment with phenoxybenzamine alone followed by washout. Although chloroquine did not affect the contraction induced by KCl in the endothelium-denuded aorta, it inhibited phenylephrine-induced protein kinase C (PKC) and myosin light-chain (MLC₂₀) phosphorylation and Rho-kinase membrane translocation. These results suggest that chloroquine inhibits vasoconstriction elicited by phenylephrine via alpha-1 adrenoceptor inhibition, which is mediated by decreased MLC₂₀ phosphorylation, the attenuation of PKC phosphorylation, and Rho-kinase membrane translocation. Full article

Schiff bases synthesized in our laboratory have demonstrated pain-relieving effects through both peripheral and central nervous system pathways. Considering that centrally acting analgesics often affect the muscle tone of the gastrointestinal tract (GIT) and related deep internal organs, this study was conducted to examine potential relaxant effects on blood vessels and GIT smooth muscles. The possible relaxant effects of Schiff bases (SB1 and SB2) on isolated rabbit aortic strips were evaluated. The experiments involved assessing their impact on contractions induced by 80 mM potassium chloride (KCL) and 1 µM norepinephrine (NE). Norepinephrine concentration response curves (N. ECRCs) were constructed in the absence and presence of three different concentrations of SB1 and SB2, using N. ECRCs as a negative control. Terazosin served as a standard α1 receptor blocker. Docking studies were employed to validate the mechanism of action for SB1 and SB2. The study outcomes suggest that SB1 is more potent than SB2, demonstrating lower EC₅₀ values for NE-induced contractions in intact (5.50 × 10⁻⁵ ± 2.23 M) and denuded (5.81 × 10⁻⁵ ± 3.80 M) aortae. For NE-induced contractions, SB1 showed percent relaxation values of 48% and 41% in intact and denuded aortae, respectively. In comparison, SB2 exhibited values of 82.5% and 74%, showing that SB1 is more efficacious than SB2. The rightward shift of N. ECRCs for both SB1 and SB2 confirms their inhibition of α1 receptors. Additive effects of SB1 and SB2 were seen in the presence of verapamil (p < 0.0001). Docking analysis revealed that the compounds can properly bind to the target receptor Gq 1D (P25100). Findings show that both Schiff base SB1 and SB2 produce significant (p < 0.05) vasorelaxation via the α1 receptor blocking mechanism. Full article

Hainan Island is the only large island located on the northern margin of the South China Sea and is surrounded by Cenozoic graben basins, including the Qiongdongnan, Yinggehai, and Beibuwan basins. The uplift and denudation history of the Jianfeng pluton on southwestern Hainan Island is significant for understanding the formation of the regional geomorphology and adjacent basin evolution. This paper presents apatite and zircon fission-track (FT) analyses conducted on the Jianfeng pluton. The zircon FT (ZFT) ages of the pluton range are from 63 ± 4 to 108 ± 8 Ma, and the apatite FT (AFT) ages are from 19.4 ± 1.8 to 43.9 ± 4.4 Ma. The average confined track lengths in apatite are relatively short (11.9–12.8 μm). An age–elevation plot indicates that two rapid cooling events occurred during 73–63 and 44–40 Ma. Thermal modeling revealed four stages of 73–63 Ma, 44–40 Ma, 40–11 Ma, and 11–0 Ma. From the Late Cretaceous to the middle Eocene (73–40 Ma), the Jianfeng area underwent episodic rapid uplift and denudation. At the end of the Late Cretaceous (73–63 Ma), the area was affected by mid-ocean ridge spreading in the Proto-South China Sea. During the middle Eocene (44–40 Ma), the Yinggehai Basin underwent abrupt expansion and subsidence, which increased the elevation difference between the Jianfeng area and the Yinggehai Basin. From the middle Eocene to the middle Miocene (40–11 Ma), the Jianfeng area underwent slow denudation, and the Yinggehai Basin was rapidly infilled, which eliminated the original elevation difference between the two areas. From the middle Miocene to the present (11–0 Ma), the Jianfeng area has undergone reactivated rapid uplift and denudation, which was driven by the remote effects of the India–Eurasia collision. Full article

Airborne particulate matter (PM) is one of the most urgent urban environment problems in the world today. The urban ecosystem has been identified as a potentially promising solution to reduce the airborne PM based on the ability of plants to retain PM. Numerous studies have been conducted to explore the process and mechanism of atmospheric PM retention by plant leaves in the past. In this study, in order to better summarize previous research, particularly the impact of leaf traits on PM retention, and to provide guidance for the selection of tree species for nature-based urban PM solutions, a systematic review was carried out using the method recommended in the PRISMA, and a total of 49 articles were selected. It was found that: 1. Asian countries contribute the majority of the proportion (32, 65%). Following behind are European countries (13, 26.5%). The American countries contribute two cases. 2. Among all the tree species, Ginkgo biloba (16), Euonymus japonicus (11), Magnolia denudate (9), Styphnolobium japonicum (9), Magnolia grandiflora (8), and Prunus cerasifera (8) emerged as hot species in research. 3. Leaf area and shape emerged as the two most frequently discussed macro-indicators, while roughness, hairiness, and stomatal characteristics were the top three micro-indicators explored. 4. Roughness and stomata, respectively, play crucial roles in capturing larger PM particles and retaining fine and ultrafine PM through their recessed structures. Trichomes decrease the likelihood of particle resuspension and boosts the efficiency of PM retention. 5. Leaves with high rigidity and complex multi-faceted leaf shapes are typically presumed to exhibit higher PM retention efficiency for higher edge effects and increased interleaf turbulence. Furthermore, with rigidity and edge effects ensured, a larger leaf area is beneficial for retaining PM. Full article

This paper reports the results of two-years’ monitoring of sand evacuation from a sandstone tableland through fissure systems and discusses the findings in the context of geomorphic evolution of tablelands, especially addressing the role of subterranean processes. A field experiment using specially designed sand collectors and involving sampling in approximately monthly intervals was carried out at six sites in SW Poland, representing two adjacent but contrasting settings: a mesa and a cuesta front. Data about sand deposition were then analyzed against precipitation data from a station located next to the sites. Sediment volumes deposited during the monitoring period were considerably different between the sites, with those at the mesa much higher than those at the cuesta. This is attributed to strong structural control influencing groundwater circulation pathways and the size of underground drainage systems, which were much smaller next to the cuesta front. Relationships between denudation and precipitation are complex, although the role of very high rainfall events appears clear, especially for the mesa. In general, precipitation in excess of 70 mm during a few consecutive days typically resulted in a considerable outflow of sand. This study highlights the role of mechanical underground erosion in sandstone tablelands, long neglected, and quantifies the denudation process. Full article

Shale gas is a prospective cleaner energy resource and the exploration and development of shale gas has made breakthroughs in many countries. Structure deformation is one of the main controlling factors of shale gas accumulation and enrichment in complex tectonic areas in southern China. In order to estimate the shale gas capacity of structurally deformed shale reservoirs, it is necessary to understand the systematic evolution of organic pores in the process of structural deformation. In particular, as the main storage space of high-over-mature marine shale reservoirs, the organic matter pore system directly affects the occurrence and migration of shale gas; however, there is a lack of systematic research on the fractal characteristics and deformation mechanism of organic pores under the background of different tectonic stresses. Therefore, to clarify the above issues, modular automated processing system (MAPS) scanning, low-pressure gas adsorption, quantitative evaluation of minerals by scanning (QEMSCAN), and focused ion beam scanning electron microscopy (FIB-SEM) were performed and interpreted with fractal and morphology analyses to investigate the deformation mechanisms and structure of organic pores from different tectonic units in Silurian Longmaxi shale. Results showed that in stress concentration areas such as around veins or high-angle fractures, the organic pore length-width ratio and the fractal dimension are higher, indicating that the pore is more obviously modified by stress. Under different tectonic backgrounds, the shale reservoir in Weiyuan suffered severe denudation and stronger tectonic compression during burial, which means that the organic pores are dominated by long strip pores and slit-shaped pores with high fractal dimension, while the pressure coefficient in Luzhou is high and the structural compression is weak, resulting in suborbicular pores and ink bottle pores with low fractal dimension. The porosity and permeability of different forms of organic pores are also obviously different; the connectivity of honeycomb pores with the smallest fractal dimension is the worst, that of suborbicular organic pores is medium, and that of long strip organic pores with the highest fractal dimension is the best. This study provides more mechanism discussion and case analysis for the microscopic heterogeneity of organic pores in shale reservoirs and also provides a new analysis perspective for the mechanism of shale gas productivity differences in different stress–strain environments. Full article

Lipid emulsions are used as adjuvant drugs to alleviate intractable cardiovascular collapse induced by drug toxicity. We aimed to examine the effect of lipid emulsions on labetalol-induced vasodilation and the underlying mechanism in the isolated rat aorta. We studied the effects of endothelial denudation, N^W-nitro-l-arginine methyl ester (l-NAME), calmidazolium, methylene blue, 1H-[1,2,4]oxadiazolo[4,3-a] quinoxalin-1-one (ODQ), and lipid emulsions on labetalol-induced vasodilation. We also evaluated the effects of lipid emulsions on cyclic guanosine monophosphate (cGMP) formation, endothelial nitric oxide synthase (eNOS) phosphorylation, and endothelial calcium levels induced by labetalol. Labetalol-induced vasodilation was higher in endothelium-intact aortas than that in endothelium-denuded aortas. l-NAME, calmidazolium, methylene blue, and ODQ inhibited labetalol-induced vasodilation in endothelium-intact aortas. Lipid emulsions inhibited labetalol-induced vasodilation in endothelium-intact and endothelium-denuded aortas. l-NAME, ODQ, and lipid emulsions inhibited labetalol-induced cGMP formation in endothelium-intact aortas. Lipid emulsions reversed the stimulatory and inhibitory eNOS (Ser1177 and Thr495) phosphorylation induced by labetalol in human umbilical vein endothelial cells and inhibited the labetalol-induced endothelial calcium increase. Moreover, it decreased labetalol concentration. These results suggest that lipid emulsions inhibit vasodilation induced by toxic doses of labetalol, which is mediated by the inhibition of endothelial nitric oxide release and reduction of labetalol concentration. Full article

Given the recent evidence in the clinical application of regenerative medicine, mostly on integumentary systems, we focused our interests on recent bladder regeneration approaches based on mesenchymal stem cells (MSCs), platelet-rich plasma (PRP), and hyaluronic acid (HA) in the treatment of interstitial cystitis/bladder pain syndrome (IC/BPS) in humans. IC/BPS is a heterogeneous chronic disease with not-well-understood etiology, characterized by suprapubic pain related to bladder filling and urothelium dysfunction, in which the impairment of immunological processes seems to play an important role. The histopathological features of IC include ulceration of the mucosa, edema, denuded urothelium, and increased detection of mast cells and other inflammatory cells. A deeper understanding of the molecular mechanism underlying this disease is essential for the selection of the right therapeutic approach. In fact, although various therapeutic strategies exist, no efficient therapy for IC/BPS has been discovered yet. This review gives an overview of the clinical and pathological features of IC/BPS, with a particular focus on the molecular pathways involved and a special interest in the ongoing few investigational therapies in IC/BPS, which use new regenerative medicine approaches, and their synergetic combination. Good knowledge of the molecular aspects related to stem cell-, PRP-, and biomaterial-based treatments, as well as the understanding of the molecular mechanism of this pathology, will allow for the selection of the right and best use of regenerative approaches of structures involving connective tissue and epithelia, as well as in other diseases. Full article

Hypersonic vehicles encounter hostile service environments of thermal/mechanical/chemical coupling, so thermal protection materials are crucial and essential. Ceramizable composites have recently attracted intensive interest due to their ability to provide large-area thermal protection for hypersonic vehicles. In this work, a novel ceramizable composite of quartz fiber/benzoxazine resin modified with fused SiO₂ and h-BN was fabricated using a prepreg compression molding technique. The effects of the fused SiO₂ and h-BN contents on the thermal, mechanical, and ablative properties of the ceramizable composite were systematically investigated. The ceramizable composite with an optimized amount of fused SiO₂ and h-BN exhibited superb thermal stability, with a peak degradation temperature and residue yield at 1400 °C of 533.2 °C and 71.5%, respectively. Moreover, the modified ceramizable composite exhibited excellent load-bearing capacity with a flexural strength of 402.2 MPa and superior ablation resistance with a linear ablation rate of 0.0147 mm/s at a heat flux of 4.2 MW/m², which was significantly better than the pristine quartz fiber/benzoxazine resin composite. In addition, possible ablation mechanisms were revealed based on the microstructure analysis, phase transformation, chemical bonding states, and the degree of graphitization of the ceramized products. The readily oxidized pyrolytic carbon (PyC) and the SiO₂ with a relatively low melting point were converted in situ into refractory carbide. Thus, a robust thermal protective barrier with SiC as the skeleton and borosilicate glass as the matrix protected the composite from severe thermochemical erosion and thermomechanical denudation. Full article

The aim of this review was to provide dentists with comprehensive information regarding dentin hypersensitivity. This includes presenting its etiology, outlining the process of diagnosis, discussing clinical management strategies, and exploring technical approaches aimed at alleviating sensitivity. Dentin hypersensitivity is characterized by distinctive short, sharp pain arising from exposed cervical dentin in response to various external stimuli. The etiological factors cause two specific changes in teeth. First, the dentin surface must be exposed and denuded, which requires the loss of enamel or gingival recession combined with the loss of cementum. The second condition is the opening of the dentin tubules to allow the sensory mechanisms in the pulpal area following stimulation of the dentin surface. The accurate diagnosis of dentin hypersensitivity before receiving therapies is critical for successful treatment. The diagnosis of the disease starts through investigating the medical history of the patient and examination. In the examination, some techniques such as air stream and water rinsing are used in order to simulate the stimulating factors and to determine the degree of pain of the patient. Numerous materials and methods have been proposed to reduce or alleviate sensitivity. These materials typically exert their effects by either sealing dentin tubules or disrupting the transmission of nerve impulses. Generally, the primary approach in addressing dentin hypersensitivity involves the utilization of toothpaste containing potassium salts and fluoride. Newly introduced materials and in-office methods for treating dentin hypersensitivity include bioactive glasses, iontophoresis, CPP-ACP, and lasers. Full article

Overpressure is an important phenomenon observed in sedimentary basins. To enhance the precision of identifying the origin of overpressure and predicting it accurately, this paper presents four practical methods for analyzing formation overpressure, taking into account various factors, such as burial history, rock properties, mechanical models and data quality. By illustrating the application examples in typical basins, this paper demonstrates the practicality and potential of each model. Based on the analysis of organic matter content and denudation, our understanding of the origin of overpressure in the first member of the Cretaceous Qingshankou Formation in Songliao Basin has been revised. A novel model based on the static equilibrium equation was established, which not only demonstrates theoretical rationality but also exhibits practical advantages in the Junggar Basin and Southeast Hainan Basin. The incorporation of lateral loading in the correction model and the utilization of colored inversion in seismic velocity processing model have significantly enhanced pressure prediction accuracy in Junggar Basin and Southeast Hainan Basin, respectively. In conclusion, these correction models demonstrate a high level of reliability and possess significant potential for widespread adoption. Full article