Search Results (12)

Hydrogen sulfide (H₂S) exerts regulatory functions in kidney diseases. However, its protective role against kidney stone formation remains unclear. Here, we demonstrate that hyperoxaluria or oxalate exposure impairs H₂S formation, leading to tubular injury and calcium oxalate (CaOx) crystal deposition in both in vivo and in vitro models. In male rats fed 5% hydroxy-L-proline (HP), time-dependent increases in urinary supersaturation, tubular damage, and renal CaOx deposition were observed compared to controls. These changes were associated with the decreased expression of H₂S-producing enzymes and elevated urinary secretion of osteopontin (OPN) and Tamm–Horsfall protein (THP). Notably, the protein level and activity of specificity protein 1 (Sp1), a transcription factor regulating these enzymes, were markedly decreased in HP-treated kidneys. Chronic supplementation with the H₂S donor GYY4137 (GYY) significantly attenuated HP-induced tubular injury and CaOx deposition by reducing OPN and THP secretion. Consistent with in vivo results, H₂S donors mitigated oxalate-induced tubular cell damage and CaOx formation in MDCK cells. Mechanistically, oxalate activated cyclic AMP/protein kinase A (PKA) signaling, which promoted OPN and THP secretion; these effects were eradicated by the PKA inhibitor H89 or GYY. These findings indicate that hyperoxaluria impairs Sp1 transcriptional activity, resulting in H₂S deficiency and compromised anticrystallization defense in oxalate-induced tubulopathy. Full article

Tunnel drainage pipes are prone to blockage due to mineral crystallization and deposition from water, which seriously affects the long-term stable operation of the drainage system and compromises the safety of tunnel structures. To address this issue, it is imperative to develop efficient anti-crystallization technologies to extend the service life of drainage systems. In this study, a series of anti-crystallization performance experiments on tunnel drainage pipes were designed and conducted based on magnetic treatment technology. The inhibitory effects of magnetic fields on crystal formation and deposition were systematically investigated under various conditions, including different magnetic field intensities, magnetic field coverage angles, magnetic field orientations, and water flow velocities. The results indicate that under magnetic influence, the crystal morphology inside the pipes changed from regular cubic structures to irregular forms with rough surfaces and loose structures, showing a transformation trend from calcite to aragonite and vaterite. Compared with conventional PVC pipes, the anti-crystallization effect was most pronounced under the following conditions: magnetic field intensity of 40 Gs, coverage angle of 90°, vertical magnetic field orientation, and higher water flow velocity. The findings of this study provide a novel approach to mitigating crystallization-induced blockages in tunnel drainage systems and contribute to reducing tunnel-related pathologies such as lining cracks, water seepage, and structural deterioration caused by poor drainage. Full article

Crystallization-induced blockages in tunnel drainage systems pose significant challenges to their functionality and longevity. To address this issue, this study proposes a novel adaptive drainage pipe designed to prevent crystallization. By constructing an indoor experimental model for anti-crystallization tests, combined with scanning electron microscopy (SEM) and molecular dynamics simulations, this study investigates the mechanism and effectiveness of the proposed system. The findings reveal that flexible PVC pipes in dynamic flow and expansion states significantly reduce crystallization compared to conventional PVC pipes. Among tested materials, EVA and TPU demonstrate superior crystallization resistance, with EVA exhibiting the lowest crystallization accumulation (7.13 g/m). Molecular dynamics simulations further elucidated the influence of material properties on the diffusion coefficient and binding energy of calcium carbonate crystals, with EVA showing the lowest binding energy with calcium carbonate at 135.11 kcal/mol, ultimately confirming EVA as the optimal material for crystallization prevention. These results offer new strategies and valuable references for managing crystallization in tunnel drainage systems. Full article

Amorphous phase separation (APS) is ubiquitously found in a large number of glass systems, because the glass can be regarded as solid with a heterogeneous structure at the nanoscale. However, little attention has been paid to the big challenges in utilizing APS in searching novel amorphous glass from above to below, which highlights the meticulous microstructure tunability of glass. Correspondingly, we develop a novel SiO₂-Al₂O₃-P₂O₅-Li₂O-ZrO₂ glass with APS (SAPLZ APS) which has robust crystallization resistance via the APS engineering. A comparative study is conducted to reveal the APS–crystallization property relationship. It can be found that the introduced APS can substantially impede the precipitated crystal growth in the studied glass system. Considering detailed glassy structure and microstructure, a diffusion barrier around each Li-rich droplet is created by the presence of P⁵⁺ concentration surrounding the Li-rich region. Meanwhile, due to the increase in Q⁴ at the expense of Q³, the polymerization degree in the Si-rich amorphous area can be enhanced, further increasing its viscosity and raising the kinetic barrier of Si-related crystal growth. These findings provide a new manner to develop new glass with superior anti-crystallization performance. Full article

Proteus mirabilis urinary tract infections can lead to serious complications such as development of urinary stones. Lactobacillus spp., belonging to the natural microbiota of the urinary tract, exhibit a number of antagonistic mechanisms against uropathogens, including the secretion of organic acids. In this study, we determined the anti-adhesion, anti-cytotoxicity and anti-crystallization properties of the substances secreted by Lactobacillus. For this purpose, membrane inserts with a pore diameter 0.4 μm were used, which prevent mixing of cultured cells, simultaneously enabling the diffusion of metabolic products. The intensity of crystallization was assessed by measuring the levels of Ca²⁺, Mg²⁺ and NH₃ and by observing crystals using microscopic methods. The cytotoxicity of the HCV-29 cell line was determined using the LDH and MTT assays, and the impact of lactobacilli on P. mirabilis adhesion to the bladder epithelium was assessed by establishing CFU/mL after cell lysis. It was shown that in the presence of L. gasseri the adhesion of P. mirabilis and the cytotoxicity of the cells decreased. The degree of crystallization was also inhibited in all experimental models. Moreover, it was demonstrated that L. gasseri is characterized by the secretion of a high concentration of L-lactic acid. These results indicate that L-lactic acid secreted by L. gasseri has a significant impact on the crystallization process and pathogenicity of P. mirabilis. Full article

The poor opening dynamic characteristics of molten salt check valves, used in concentrating solar thermal systems, constitute the main cause of valve disc oscillation and low pressure difference difficulty in opening during molten salt delivery. A molten salt swing check valve is designed to meet the requirements of high-temperature and high-pressure sealing and anti-crystallization flow channels. A transient dynamics model of the valve motion components is established, dynamic mesh and UDF (user-defined function) techniques are used to simulate the non-constant flow of hot molten salt and the opening process of the check valve and to analyze the dynamic characteristics of the opening process. Topological optimization of the valve motion components is proposed for the first time in order to improve the opening performance of the check valve, and the topological optimization of the valve motion components is based on the solid isotropic material penalty (SIMP) model with the variable density method and thermal–fluid–mechanical coupling method. The design is also verified for the dangerous working condition of a molten salt hammer. The results show that the mass of the valve motion component is reduced by 57.76% after optimization while meeting the requirements of strength and stiffness. The optimized molten salt check valve achieves a larger angle and faster opening, the full opening angle is increased by 6°, the positive resting pressure difference of the valve is reduced by 5 kPa, the minimum opening pressure difference is reduced by 8.9 kPa, the optimized flow characteristics are smoother, and the valve disc oscillation problem is avoided. The study provides a method for researchers to use to optimize the design of a molten salt swing check valve and its dynamic characteristics for concentrating solar power, which is of great significance in efforts to improve the stability of the molten salt transport system. Full article

Transverse drainage pipe, one of the main channels of groundwater behind the lining of subway tunnels, plays an important role in the safety and stability of the tunnel lining structure. For the problem of blocked transverse drainage pipe in a subway tunnel, a fault tree model of blocked transverse drainage pipe in Chongqing subway tunnel was constructed in this paper, the quantitative and qualitative analysis of fault tree was conducted, and countermeasures for maintenance of transverse drainage pipe were proposed. The study finds that, (1) the chemical type of groundwater was mainly CaHCO₃; most of the groundwater is strongly alkaline with pH greater than 8; the groundwater temperature is 20 ± 3 °C; (2) the basic events of blocked transverse drainage pipe have 3 minimum cut sets, and the basic events concrete slurry enters the drainage pipe; groundwater temperature, groundwater pH value, and concentration of anions and cations in groundwater were the main fault factors of blocked transverse drainage pipe; (3) preventive maintenance of transverse drainage pipe during tunnel construction includes construction quality control of drainage pipe and application of anti-crystallized blocking drainage pipe; preventive maintenance of transverse drainage pipe during tunnel operation includes monitoring of groundwater ion concentration, pH, and temperature; and maintenance treatment of transverse drainage pipe during tunnel operation includes physical treatment techniques, such as ultrasonic resonance, and chemical treatment techniques, such as acid-base neutralization reaction. The results of the study have certain guiding significance for the design, construction, and operation of transverse drainage pipe in subway tunnels. Full article

Crystal blockage of tunnel drainage pipes is one of the main causes of problems such as lining cracking and water leakage. The study of the crystal development rule is of great significance for the design of tunnel drainage systems and the long-term safety of tunnel support structures. In this paper, a series of experimental studies on the crystallization development law of drain pipes are conducted. The effects of the connection method of the drain, the diameter of the pipe, the spacing of the circular drain, and the material of the drain on the crystallization development pattern are investigated. The results show that the groundwater environment has a great influence on the crystallization development of the drain pipe. As the drain diameter and the spacing between two adjacent circular drains increased, the time for complete blockage of the drain is prolonged. The rate of crystallization on the drainage pipe can be effectively reduced by changing the material of the drainage pipe from polyamide (PA) to polypropylene (PP). The present study provides a reference for research work related to crystallization blockage in tunnel drainage pipes. Full article

A wide range of biological properties and a potent therapeutic and prophylactic effect on chronic diseases are all present in Argania spinosa L. press cake. The aim of this research is to valorize the anticrystallization properties against calcium oxalate crystals of Argania spinosa L. press cake fractions and identify its bioactive components. Chemical species identification was performed using GC–MS analysis. The turbidimetric model was used to investigate crystallization inhibition in vitro. Infrared spectroscopy technique was used to characterize the synthesized crystals. Furthermore, both DPPH and FRAP methods were used to assess antioxidant activity. The results show that the fractions are equally important in crystallization inhibition percentages of calcium oxalate crystals. For saponin and polyphenol fractions, the inhibition percentages are in the orders of 83.49% and 82.83%, respectively. The results of the antioxidant activity by DPPH method show that the two fractions are equally important in the elimination of free radicals; the inhibition percentages were 77.87 ± 4.21 and 89.92 ± 1.39 for both polyphenols and saponins, respectively. FRAP method showed that the absorbance increases proportionally with concentration, and the absorbance are almost similar for both fractions and reach maximum values in the orders of 0.52 ± 0.07 and 0.42 ± 0.03, respectively, for saponins and polyphenols. These findings demonstrate that both fractions are rich in bioactive chemicals and have an anticrystallization capacity, allowing them to be employed for the curative and prophylactic effects against urolithiasis. Full article

Crystal blockages of tunnel drainage systems severely undermine the tunnel lining structure and operation safety. In order to reduce the risk of crystal blockages of tunnel drainage systems, the distribution of highway tunnel defects was identified through a field survey, indoor test, and literature analysis, and an optimization method of tunnel drainage structures was proposed. The research suggested the following: (1) Lining water leakage and construction joint water leakage were the most common defects in the tunnel drainage system of Renhua–Xinfeng Expressway and Yingde–Huaiji Expressway in Guangdong Province, accounting for 60% and 32% of total defects, respectively. The number of defects that occurred in the drainage system of the tunnel was larger in the granite formation, with the number of road seepage and inspection chamber crystallization incidents reaching 2.5/km and 2.8/km, respectively. (2) The groundwater was mainly alkaline with a pH value of 8~12, Ca²⁺ (107 mg/L) was the cation with the largest ion concentration, and HCO₃⁻ (165 mg/L) was the anion with the largest ion concentration. The crystals in the tunnel drainage system were predominantly square, spindle, and rhombic calcite and aragonite composed of CaCO₃, mixed with a small amount of sediment. (3) To reduce the risk of crystal blockages of the tunnel drainage system and ensure tunnel lining structure safety, a threefold optimization measure was proposed, namely, setting one-directional drainage pipes between the cable trench and the roadside blind drainage ditch, applying “π” type anti-crystallization drainage water-stop belts at the circular construction joints in the secondary lining, and both increasing the slope of the transverse drainage pipe and using an anti-crystallization drainage pipe. The research results will play an important role in guiding the design, construction, and maintenance of highway tunnel drainage systems in China. Full article

The application of artemisinin (ART) in the treatment of malaria has been restricted to a certain degree due to its inherent limitations, such as short half-life, poor solubility, limited bioavailability, and re-crystallization. Electrospun nanofibers loaded with ART provide an excellent solution to these limitations and yield sustained drug release as well as inhibition of drug re-crystallization. In this study, ART-loaded polycaprolactone (PCL)/collagen (Col) nanofibers with different proportions of polymers were prepared. ART-loaded PCL/Col nanofibers were characterized, and further ART anti-crystallization and release behaviors were studied. SEM was used to observe the morphology of PCL/Col nanofibers. X-ray diffraction (XRD) was used to characterize the physical state of ART in ART-loaded PCL/Col nanofibers. Fourier transform infrared spectroscopy (FTIR), water contact angle measurement, weight loss, degree of swelling, and drug release experiments can verify the differences in performance of ART-loaded PCL/Col nanofibers due to different polymer ratios. The release curve was analyzed by kinetics, showing sustained release for up to 48 h, and followed the Fickian release mechanism, which was shown by the diffusion index value obtained from the Korsmeyer-Peppas equation. Full article

Based on the airflow rotation concept, a new packaging structure was designed to meet the performance requirements of China-VI stage emission regulations. The new structure is a hybrid structure of spiral space with small blades and conical plates. The Computational Fluid Dynamics (CFD) simulation was used to analyze the velocity uniformity and ammonia uniformity of the flow field, and the results showed that velocity uniformity and ammonia uniformity were higher than 0.95, and the possibility of crystallization risk was very low. The actual performance of the new structural prototype was verified by means of engine bench testing. The test results were excellent and the conversion efficiency reached 0.96. The new selective catalytic reduction (SCR) urea mixed structure design greatly improved the conversion efficiency of the after-treatment system and has excellent anti-crystallization performance. Full article