Search Results (48)

The dynamic non-equilibrium effect (DNE) describes the non-unique character of saturation–capillary pressure relationships observed under static, steady-state, or monotonic hydrodynamic conditions. Macroscopically, the DNE manifests as variations in soil hydraulic characteristic curves arising from varying hydrodynamic testing conditions and is fundamentally governed by soil matrix particle size distribution. Changes in the DNE across porous media with discrete particle size fractions are investigated via stepwise drying experiments. Through quantification of saturation–capillary pressure hysteresis and DNE metrics, three critical signatures are identified: (1) the temporal lag between peak capillary pressure and minimum water saturation; (2) the pressure gap between transient and equilibrium states; and (3) residual water saturation. In the four experimental sets, with the finest material (Test 1), the peak capillary pressure consistently precedes the minimum water saturation by up to 60 s. Conversely, with the coarsest material (Test 4), peak capillary pressure does not consistently precede minimum saturation, with a maximum lag of only 30 s. The pressure gap between transient and equilibrium states reached 14.04 cm H₂O in the finest sand, compared to only 2.65 cm H₂O in the coarsest sand. Simultaneously, residual water saturation was significantly higher in the finest sand (0.364) than in the coarsest sand (0.086). The results further reveal that the intensity of the DNE scales inversely with particle size and linearly with wetting phase saturation (Sw), exhibiting systematic decay as Sw decreases. Coarse media exhibit negligible hysteresis due to suppressed capillary retention; this is in stark contrast with fine sands, in which the DNE is observed to persist in advanced drying stages. These results establish pore geometry and capillary dominance as fundamental factors controlling non-equilibrium fluid dynamics, providing a mechanistic framework for the refinement of multi-phase flow models in heterogeneous porous systems. Full article

Time-domain (TD) diffuse reflectance can be modeled using diffusion theory (DT) to non-invasively estimate optical transport coefficients of biological media, which serve as markers of tissue physiology. We employ an optimized N-layer DT solver in cylindrical geometry to reconstruct optical coefficients of bilayered media from TD reflectance generated via Monte Carlo (MC) simulations. Optical properties for 384 bilayered tissue models representing human head or limb tissues were obtained from the literature at three near-infrared wavelengths. MC data were fit using the layered DT model to simultaneously recover transport coefficients in both layers. Bottom-layer absorption was recovered with errors under 0.02 cm⁻¹, and top-layer scattering was retrieved within 3 cm⁻¹ of input values. In contrast, recovered bottom-layer scattering had mean errors exceeding 50%. Total hemoglobin concentration and oxygen saturation were reconstructed for the bottom layer to within 10 μM and 5%, respectively. Extracted transport coefficients were significantly more accurate when obtained using layered DT compared to the conventional, semi-infinite DT model. Our results suggest using improved theoretical modeling to analyze TD reflectance analysis significantly improves recovery of deep-layer absorption. Full article

LiTaO₃ crystals doped with Cr³⁺ and Nd³⁺ ions are promising for developing active nonlinear laser media. In this work, the defect structure of LiTaO₃ crystals, including those doped with Cr³⁺ and Nd³⁺, is examined. X-ray patterns of all six investigated LiTaO₃:Cr:Nd crystals are identical and correspond to a highly perfect structure. Using optical microscopy, the presence of defects of various shapes, microinhomogeneities, and lacunae was revealed. The optical absorption and Raman scattering spectra of a series of nonlinear, optical, double-doped LiTaO₃:Cr³⁺:Nd³⁺ (0.06 ≤ [Cr³⁺] ≤ 0.2; 0.2 ≤ [Nd³⁺] ≤ 0.45 wt%) crystals showed that at concentrations of doping Cr³⁺ ions less than 0.09 wt% and Nd³⁺ ions less than 0.25 wt%, the crystal structure is characterized by a low level of defects, and the optical transmission spectra characterized by narrow lines corresponding to electron transitions in Nd³⁺ ions. In this case, for the radiative transition in the cation sublattice, the existence of three nonequivalent neodymium centers is observed, and for the radiative transition, two nonequivalent centers are observed. IR absorption spectroscopy in the OH⁻-stretching vibration range revealed two main spectral regions: 3463–3465 cm⁻¹, associated with stoichiometry changes, and 3486–3490 cm⁻¹, linked to complex defects such as (V^-_Li)-OH and (Ta⁴⁺_Li)-OH. A distinct low-intensity line at ~3504 cm⁻¹ was observed only in doped crystals, attributed to (Nd²⁺_Li)-OH defects that significantly distort the oxygen-octahedral clusters due to the larger ionic radius of Nd³⁺ compared to Ta⁵⁺. In contrast, Cr-related defects cause only minor distortions. The Klauer method indicated that the highest concentration of OH⁻-groups occurs in the LiTaO₃:Cr³⁺ (0.09 wt%):Nd³⁺ (0.25 wt%) crystal, where multiple complex defects are present. Full article

The seepage diffusion of cement grouting materials into a sandy medium is influenced by the skeleton’s adsorption and the pore channels’ tortuosity, resulting in heterogeneous retention of cement particles during migration. This study established a theoretical model for the filtration coefficient based on the mass balance equation and linear filtration law. Grouting tests were conducted to determine the density of the cement slurry at various diffusion positions, and the filtration coefficient was calculated using the theoretical model. Results indicate that the filtration coefficient varies dynamically along the diffusion distance rather than remaining constant. The surface filtration range of Grade 42.5 Portland Cement slurry in sample S1 is approximately 30 cm, with a final diffusion distance of 190 cm. In contrast, the surface filtration ranges for the 800 mesh superfine cement in S2 and the 1250 mesh superfine cement in S3 are less than 10 cm, resulting in final diffusion distances of 69 cm and 87 cm, respectively. This demonstrates that a longer surface filtration range in the sand sample corresponds to a farther final diffusion distance of the slurry. Additionally, a larger ratio of sand pore diameter to cement particle size results in a smaller filtration coefficient and a greater slurry diffusion distance. Under a constant water–cement ratio, smaller cement particle sizes are associated with decreased slurry fluidity, which reduces the diffusion of cement slurry within the sandy medium. The research findings provide valuable insights for designing borehole spacing in grouting treatment for sandy media. Full article

Peat is widely used as a soilless growing medium due to its favorable physicochemical properties. However, its extraction has a significant environmental impact, highlighting the need for sustainable alternatives. Repurposing residues from olive oil (OR) and wine (GR) production offers a potential solution to reduce peat dependency and promote agricultural circularity. This study investigated the effects of incorporating different ratios of OR and GR (0, 5, 10, 20, and 40% v/v) into peat-based substrates for the cultivation of chrysanthemum (Chrysanthemum morifolium cv. Pina Colada). The addition of OR and GR altered the physicochemical properties of the substrate mixtures. All mixtures maintained electrical conductivity below the maximum threshold for container media (≤0.5 mS cm⁻¹). While GR increased pH, it remained within suitable ranges at 5–10% incorporation. Adding OR decreased total porosity, while GR addition at ≥20% increased it. OR-amended substrates were associated with reduced plant growth, flower production, chlorophyll fluorescence, and relative chlorophyll content, with these effects intensifying at higher OR levels. These outcomes, combined with increased total phenolics, flavonoids, antioxidant activity, and antioxidant enzyme activities, suggest a high stress response, as indicated by increased malondialdehyde and hydrogen peroxide levels. In contrast, GR at ≤ 20% did not induce oxidative stress or negatively affect growth, physiological, or nutritional indices, making it a viable component of peat-based substrate mixtures. The suboptimal performance of OR highlights the need for improved valorization through composting, optimized application rates, and combination with other substrates or residues to enhance its suitability as a horticultural substrate component. Full article

It is of great significance to clarify the corrosion mechanism of rust layers on bronze ware for appropriate conservation measures. In this study, the corrosion behavior of Cu-Sn bronze alloys in a 3.5 wt.% NaCl solution and a simulated archaeological soil solution was studied and compared using electrochemical measurements, microscopic observations, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results showed that the presence of Cl⁻ was the key factor leading to the formation of harmful rust such as Cu₂(OH)Cl₃. In the NaCl solution, the rapid accumulation of Cl-containing corrosion products provided a certain degree of protection to Cu-Sn alloys, but the products easily fell off, thus increasing the continuous corrosion reactions again. This resulted in a significant increase in the corrosion rate of the alloy (i_corr from 4.845 μA·cm⁻² to 27.21 μA·cm⁻²) and a decrease in polarization resistance (R_p from 5.17 kΩ·cm² to 3.27 kΩ·cm²). In contrast, the corrosion reactions of the Cu-Sn alloy were dominated by complex ions other than Cl⁻ in archaeological soil environments, and the corrosion products tended to form stable and dense rust layers (i_corr was always lower than 1.6 μA·cm⁻², and R_p was maintained above 24 kΩ·cm²), which improved corrosion resistance by two orders of magnitude compared to the unstable rust layer that formed in NaCl solution. In addition, Cl-containing corrosion products boosted the wettability of rust layers, thereby facilitating penetration of corrosive media that strengthened corrosion reactions. This study deepens our understanding of the degradation mechanisms of bronze artifacts and provides a scientific basis for developing bronze conservation strategies. Full article

Hydrogen production via water splitting is one of the latest low-cost green hydrogen production technologies. The challenge is to develop inexpensive and highly active catalysts. Herein, we present the preparation of electrocatalysts based on cobalt–phosphorus (Co-P) coatings with different P contents for hydrogen and oxygen evolution reactions (HER and OER). The Co-P coatings were deposited on the copper (Cu) surface using the economical and simple method of electroless metal deposition. The morphology, structure, and composition of the Co-P coatings deposited on the Cu surface were studied via scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), while their activity for HER and OER in 1 M KOH was investigated using linear sweep voltammetry (LSV) and chrono-techniques. It was found that the catalyst activity for both HER and OER depends on the P content of the catalyst and varies based on the highest efficiency for each reaction. The Co-P coating with 11 wt% P exhibited the lowest overpotential value of 98.9 mV for the HER to obtain a current density of 10 mA cm⁻² compared to the Co-P coatings with 8, 5, 1.6, and 0.4 wt% P (107.6, 165.9, 218.2, and 253.9 mV, respectively). In contrast, the lowest OER overpotential (378 mV) was observed for the Co-P coating with 8 wt% P to obtain a current density of 10 mA cm⁻² as compared to the Co-P coatings with 5, 11, 1.6, and 0.4 wt% P (400, 413, 434, and 434 mV, respectively). These results suggest that the obtained catalysts are suitable for HER and OER in alkaline media. Full article

Background: Having a laboratory renal profile for medical imaging examinations requiring contrast media (CM) administration is strongly advised. Creatinine helps identify patients at risk of contrast-induced nephropathy (CIN). The GEM^® Premier™ ChemSTAT (Werfen) is a point-of-care (POC) analyzer with 12 emergency parameters, including a creatinine assay. This study aims to compare ChemSTAT with the central analytical solution of the University Hospital of Clermont-Ferrand and to evaluate the interest in using POC creatinine in the emergency department (ED) to optimize the flow of patients, especially when CM administration is necessary. Methods: More than 200 whole blood (WB) samples from the ED were evaluated on the ChemSTAT analyzer. As comparative methods, the plasma aliquots from the same samples were assayed on an Atellica^® CH (Siemens Healthineers). The clinical concordance was assessed according to the decision cut-offs of the French Society of Radiology for the risk of CIN. The availability times of biological results between ChemSTAT and the central laboratory were studied. Results: WB results from the ChemSTAT analyzer correlated well with those from the Atellica^® CH, except for tCO2 (the known bias between the Siemens and Cobas Roche methods for predicting ChemSTAT values). The results of the creatinine assay allow for identical medical decisions in comparison to the renal-risk cut-offs. The availability of the biological results was reduced by 50 min on average with ChemSTAT vs the central laboratory. Computed tomography (CT) was performed for 44.7% of patients, including the injection of the CM in 68% of cases. For these patients, the availability of creatinine results relative to imaging time is faster with the ChemSTAT by an average of 45.2 min. Conclusions: Great analytical and clinical correlations for creatinine assays allow for the safe identification of patients at risk of CIN, and improve patient flow in ED, especially for those requiring computed tomography with CM. Full article

Light non-aqueous phase liquids (LNAPLs), which include various petroleum products, are a significant source of groundwater contamination globally. Once introduced into the subsurface, these contaminants tend to accumulate in the vadose zone, causing chronic soil and water pollution. The vadose zone often contains lens-shaped bodies with diverse properties that can significantly influence the migration and distribution of LNAPLs. Understanding the interaction between LNAPLs and these lens-shaped bodies is crucial for developing effective environmental management and remediation strategies. Prior research has primarily focused on LNAPL behavior in homogeneous media, with less emphasis on the impact of heterogeneous conditions introduced by lens-shaped bodies. To investigate the impact of lens-shaped structures on the migration of LNAPLs and to assess the specific effects of different types of lens-shaped structures on the distribution characteristics of LNAPL migration, this study simulates the LNAPL leakage process using an indoor two-dimensional sandbox. Three distinct test groups were conducted: one with no lens-shaped aquifer, one with a low-permeability lens, and one with a high-permeability lens. This study employs a combination of oil front curve mapping and high-density resistivity imaging techniques to systematically evaluate how the presence of lens-shaped structures affects the migration behavior, distribution patterns, and corresponding resistivity anomalies of LNAPLs. The results indicate that the migration rate and distribution characteristics of LNAPLs are influenced by the presence of a lens in the gas band of the envelope. The maximum vertical migration distances of the LNAPL are as follows: high-permeability lens (45 cm), no lens-shaped aquifer (40 cm), and low-permeability lens (35 cm). Horizontally, the maximum migration distances of the LNAPL to the upper part of the lens body decreases in the order of low-permeability lens, high-permeability lens, and no lens-shaped aquifer. The low-permeability lens impedes the vertical migration of the LNAPL, significantly affecting its migration path. It creates a flow around effect, hindering the downward migration of the LNAPL. In contrast, the high-permeability lens has a weaker retention effect and creates preferential flow paths, promoting the downward migration of the LNAPL. Under conditions with no lens-shaped aquifer and a high-permeability lens, the region of positive resistivity change rate is symmetrical around the axis where the injection point is located. Future research should explore the impact of various LNAPL types, lens geometries, and water table fluctuations on migration patterns. Incorporating numerical simulations could provide deeper insights into the mechanisms controlling LNAPL migration in heterogeneous subsurface environments. Full article

Background: Our study aims to provide an overview of existing evidence regarding the image quality of dual-energy CT (DECT) employing reduced contrast media (CM) volumes, in comparison to single-energy CT (SECT) with standard CM loads. The advantages, indications, and possible applications of DECT were investigated from the perspective of providing better patient care, minimizing CM volume and managing CM shortage. Methods: In this systematic review (PRISMA methodology), PubMed and WOS were searched from January 2010 to January 2023 by two independent reviewers. The scan and CM characteristics, radiation dose, and results of quantitative (contrast to noise ratio, CNR, and signal to noise ratio, SNR) and qualitative assessment of image quality were collected. Sixty non-duplicated records eligible for full-text screening were examined. Results: Finally, 22 articles (1818 patients) were included. The average CM reduction with DECT ranged between 43.4 ± 11%. Despite the wide variability in CT scan protocols, no differences were found in radiation doses between DECT and SECT. Conclusions: DECT scanners allow the employment of lower CM volumes with equal or better image quality evaluated by quantitative and qualitative analyses and similar dose radiation compared to SECT. Using image reconstructions at low monochromatic energy levels, DECT increases iodine conspicuity and attenuation contributing to CM containment measures. Full article

Background: Acute kidney injury (AKI) as a result of iodinated contrast media (CM) has been linked to CM-induced renal ischemia and toxic effects on endothelial cells (EC). The recombinant human C1 inhibitor (rhC1INH) has been shown to influence EC activation. Methods: Secondary analysis of 74/77 (96%) participants of a double-blind, randomized, and placebo-controlled study that assessed the effect of rhC1INH on AKI. E-selectin, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule (VCAM-1), and CC-chemokin-ligand-5 (CCL5) were determined in frozen blood samples over 48 h and analyzed according to the treatment group and renal outcomes. Results: The mean age was 76.7 years, and 37 patients each received rhC1INH and placebo, respectively. In the entire study population, minor differences in median EC activation markers/CCL5 concentrations during the first 48 h compared to baseline were observed (e.g., E-selectin 27.5 ng/mL at baseline vs. 29.7 ng/mL on day 1, CCL5: 17.7 ng/mL at baseline vs. 32.2 ng/mL on day 2). Absolute changes in ICAM-1/E-selectin concentrations correlated with a higher peak change in urinary NGAL concentrations. However, AKI was not associated with significant changes in EC markers/CCL5. Last, no significant differences in serum concentrations of EC activation markers/CCL5 were evident between the placebo and the rhC1INH group. Conclusions: CM administration during coronary angiography only mildly activated ECs within the first 48 h, which does not explain subsequent AKI. The administration of rhC1INH was not associated with a reduction of EC activation or CCL5. Full article

Flow induced by an orbital shaker is known to produce shear stress and oscillatory flow, but the utility of this model for studying mechanical loading effects in osteoblasts is not well defined. To test this, osteoblasts derived from the long bones of adult male C57BL/6J mice were plated on 6-well plates and subjected to orbital shaking at various frequencies (0.7, 1.4, and 3.3 Hz) for 30 and 60 min in serum-free differentiation media. The shear stress on cells produced by 0.7, 1.4, and 3.3 Hz shaking frequencies were 1.6, 4.5, and 11.8 dynes/cm², respectively. ALP activity measured 72 h after shaking (orbital flow) showed a significant increase at 0.7 and 1.4 Hz, but not at 3.3 Hz, compared to static controls. Orbital flow-induced mechanical stress also significantly increased (25%) osteoblast proliferation at a 0.7 Hz flow compared to static controls. Additionally, expression levels of bone formation markers Osf2, Hif1a, Vegf, and Cox2 were significantly increased (1.5- to 3-fold, p < 0.05) in cells subjected to a 0.7 Hz flow compared to non-loaded control cells. We also evaluated the effect of orbital flow on key signaling pathways (mTOR, JNK, and WNT) known to mediate mechanical strain effects on osteoblasts. We found that blocking mTOR and WNT signaling with inhibitors significantly reduced (20–30%) orbital flow-induced ALP activity compared to cells treated using a vehicle. In contrast, inhibition of JNK signaling did not affect flow-induced osteoblast differentiation. In conclusion, our findings show that the flow produced by an orbital shaker at a lower frequency is an appropriate inexpensive model for studying the molecular pathways mediating mechanical strain effects on primary cultures of osteoblasts in vitro. Full article

The utilization of contrast media (CM) in clinical diagnostic imaging and interventional procedures has escalated, leading to a gradual increase in the incidence of contrast-induced acute kidney injury (CI-AKI). Presently, the scarcity of effective pharmacological treatments for CI-AKI poses significant challenges to clinical management. Firstly, we explore the pathogenesis of CI-AKI in this review. Beyond renal medullary ischemia and hypoxia, oxidative stress, cellular apoptosis, and inflammation, emerging mechanisms such as ferroptosis, release of neutrophil extracellular traps (NETs), and nitrosative stress, which offer promising avenues for the management of CI-AKI, are identified. Secondly, a comprehensive strategy for the early prevention of CI-AKI is introduced. Investigating the risk factors associated with CI-AKI is essential for the timely identification of high-risk groups. Additionally, exploring early sensitive biomarkers is crucial for early diagnosis. A synergistic approach that combines these sensitive biomarkers, CI-AKI risk factors, and disease risk prediction models enhances both the accuracy and efficiency of early diagnostic processes. Finally, we explore recent pharmacological and non-pharmacological interventions for the management of Cl-AKI. Beyond the traditional focus on the antioxidant N-acetylcysteine (NAC), we look at active compounds from traditional Chinese medicine, including tetramethylpyrazine (TMP), salvianolic acid B (Sal B), as well as emerging preventive medications like N-acetylcysteine amide (NACA), alprostadil, and others, which all showed potential benefits in animal and clinical studies for CI-AKI prevention. Furthermore, innovative strategies such as calorie restriction (CR), enhanced external counterpulsation (EECP), and mesenchymal stem cell therapy are highlighted as providing fresh insights into Cl-AKI prevention and management. Full article

Contrast-Induced Acute Kidney Injury (CI-AKI) remains a frequent iatrogenic condition since radiological procedures using intra-vascular iodinated contrast media (CM) are being widely administered for diagnostic and therapeutic purposes. Despite the improvement of the medical healthcare system worldwide, CI-AKI is still associated with direct short-term and indirect long-term outcomes including increased morbidity and mortality, especially in patients with underlying pre-existing renal function impairment, cardiovascular disease, or diabetes that could rapidly progress into Chronic Kidney Disease. Although the RIFLE (Risk, Injury, Failure, Loss, End-Stage Kidney Disease), AKIN (Acute Kidney Injury Network), and KDIGO (Kidney Disease Improving Global Outcomes) clinical criteria and recommendation guidelines are based on traditional “gold standard” biomarkers known as serum creatinine, glomerular filtration rate, and urinary output, new reliable serum and urinary biomarkers are still needed for an effective unified diagnostic strategy for AKI. Starting from previous and recent publications on the benefits and limitations of validated biomarkers responding to kidney injury, glomerular filtration, and inflammation among others, this review unravels the role of new emerging biomarkers used alone or in combination as reliable tools for early diagnosis and prognosis of CI-AKI, taking into account patients and procedures-risk factors towards a new clinical perspective. Full article

To control the spread of bacteria and viruses on surfaces in medical environments and everyday life, suitable disinfection methods are required. Visible radiation in the violet or blue spectral range is known to exhibit an antimicrobial impact on microorganisms. However, so far most published studies were performed on liquids. In contrast, the sensitivity of microorganisms to visible radiation on surfaces was only investigated in a few studies. In order to transfer possible conclusions from irradiation in media to irradiation on surfaces and to apply visible light as a possible valid alternative for common disinfection methods, the log reduction doses for surfaces and liquids were compared in this study. The non-pathogenic Staphylococcus carnosus was selected as a surrogate for the ESKAPE pathogen Staphylococcus aureus, as the experiments were performed in an S1 laboratory. The irradiations were performed with wavelengths of 403 nm (violet) and 453 nm (blue). The observed log reduction doses in liquids (literature with the same strain and setup) and on surfaces (this investigation) were 101.8 J/cm² and 14.0 J/cm² at 403 nm and 374.3 J/cm² and 112.8 J/cm² at 453 nm, respectively. The results suggest that the photosensitivity of S. carnosus on surfaces is much higher than in that liquid with a ratio of 7.3 (violet) to 3.3 (blue). On the one hand, this demonstrates that irradiation on surfaces is more efficient than that in liquids, especially in the violet spectral range. On the other hand, depending on the strength of the irradiation source, disinfection with visible irradiation is a useful alternative to conventional disinfection methods. Full article