Search Results (1,311)

Tungsten is an extremely durable metal with a wide range of industrial applications and its toxicity is relatively low, although chronic exposure to its compounds can lead to adverse health effects. This paper proposes a method for the determination of trace amounts of tungsten using cathodic stripping voltammetry (CSV). A hybrid structure based on a mixture of multi-walled carbon nanotubes and spherical glassy carbon was used as the working electrode, on the surface of which a film of lead was formed during the measurement to increase the efficiency of the determination. A comprehensive optimization of the analytical parameters, including accumulation potential and time, signal recording conditions and electrolyte solution composition, was carried out to maximize sensitivity and improve the signal-to-noise ratio. The method developed achieved a detection limit for tungsten of 3 × 10⁻¹⁰ mol L⁻¹, demonstrating its high sensitivity. The working electrode showed selectivity, signal reproducibility and resistance to the presence of potential interferences. The reliability and applicability of the proposed solution were confirmed by applying the method to the analysis of real environmental samples and certified reference materials, with satisfactory results. The presented analytical procedure represents a promising tool for the routine determination of tungsten in complex real matrices. Full article

Friction in sheet metal forming processes is a key factor determining the material flow behavior and surface quality of products. Controlling friction conditions is crucial for ensuring the stability of the forming process. This article focuses on evaluating the influence of strip sample orientation, tool surface roughness, and contact forces on the coefficient of friction in the strip drawing test. Low-carbon, deep-drawing-quality steel sheets produced by rolling were used as the test material. Due to the complex influence of numerous parameters on the coefficient of friction, analysis of variance (ANOVA) was employed to evaluate the experimental results. A two-factor interaction model was used to analyze the data from the strip drawing test. An adequate precision of approximately 104.74 and coefficients of determination of R² = 0.9367, an adjusted R² = 0.9350, and a predicted R² = 0.9331 indicated that the regression model was sufficiently fitted to provide reliable predictions. It was found that the influence of sheet orientation on the coefficient of friction, under a varying load force, was minor; the difference in the CoF between the two sample orientations did not exceed about 0.01. On the other hand, among all the parameters of the strip drawing test, the load force was the decisive factor affecting the CoF. A trend was observed in which the coefficient of friction increased with a decreasing average roughness of the countersamples and load force. Full article

The tortured and mutilated bodies of seven virgin martyrs stand side by side in an antependium woven around 1430 in Nuremberg. The Virgin Martyrs Tapestry is a striking representation of female saints’ martyrdoms that has yet to be fully analyzed for its potential contributions to discourses about hagiographic iconography, suffering and pain, religious constructs of gender, and sexualized violence in the fifteenth century. Nuanced interpretations of the iconography, with reference to images of Christ, enlighten and recontextualize the tapestry’s brutal depiction of the virgin martyrs. My analysis of the tapestry engages with this unusual presentation of virgin martyrs, stripped and statically accepting brutal torture that far exceeds their textual legends by weapons wielded by disembodied hands, as avenues for imitatio Christi. This interpretation considers the tapestry’s visual program, its enigmatic portrayal of torturing hands, late medieval attitudes toward pain and suffering, and the phenomenon of Christian women “becoming male” to transcend their femininity. Theologically and iconographically, the martyrs’ portrayals in the tapestry mirror the human and divine aspects of Christ. Full article

Feline conjunctivitis is a common ocular disorder; however, the molecular composition of feline tear fluid and its alterations during ocular surface inflammation remain poorly characterized. This pilot study aimed to explore the tear proteome of cats with conjunctivitis using matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI–TOF/TOF MS) and to compare findings with those from clinically healthy cats. Tear samples were collected using Schirmer tear test strips from healthy cats and cats diagnosed with conjunctivitis. Total protein concentration was measured by ultraviolet absorbance spectrophotometry, and tear proteins were separated by SDS–polyacrylamide gel electrophoresis, followed by in-gel trypsin digestion and MALDI–TOF/TOF MS analysis. Nine distinct tear proteins were identified, including antimicrobial and immune-related components such as lactoperoxidase, lactotransferrin, albumin, and immunoglobulin A constant region. Lactoperoxidase and SBP1 were identified in feline tear fluid for the first time. No proteins uniquely associated with conjunctivitis were detected. The mean total tear protein concentration was numerically higher in cats with conjunctivitis (13.06 ± 0.75 mg/mL) than in healthy cats (9.69 ± 0.67 mg/mL); however, this difference did not reach statistical significance (p = 0.095) and should be interpreted cautiously given the limited sample size. This pilot study provides preliminary insights into tear protein profiles in cats with conjunctivitis and highlights the need for larger quantitative investigations. These findings provide a preliminary framework for future studies aimed at further characterizing molecular alterations associated with feline ocular surface disorders. Full article

The application of machine learning (ML) methods enables the modeling of sheet metal friction phenomena based on experimental data, allowing for the prediction of the coefficient of friction (CoF) under various operating conditions. The aim of this article is to compare the predictive capability of a wide range of ML algorithms trained on the results of the strip drawing test. The variable parameters in the strip drawing test were sheet orientation, load, sample orientation relative to the sheet rolling direction, and the drawing quality of the low-carbon steel sheet metal. Based on the coefficient of determination (R²) and the root mean squared error (RMSE), it was determined that the best predictive performance was achieved by a trilayer neural network (R² = 0.986, RMSE = 0.0025). It was found that the CoF decreased with increasing countersample surface roughness and load. Meanwhile, the orientation of strip samples relative to the sheet rolling direction had a statistically insignificant effect on the CoF. Based on SHapley Additive exPlanations (SHAP) values, it was shown that the average roughness of the countersamples and the load had the most significant influence on the friction coefficient. This was also confirmed using the F-test and permutation importance analysis of the friction process parameters. Full article

Steel jackets are widely used for the seismic retrofitting of reinforced concrete (RC) beam–column joints. However, the details and efficiencies of steel jackets are directly impacted by the presence of transverse beams. An in-depth understanding of this issue has been lacking so far. In this study, using realistic configurations of transverse beams, the seismic performance of exterior RC beam–column joints retrofitted according to the modified steel jacketing method were investigated numerically and theoretically. The refined nonlinear three-dimensional finite element approach was adopted and verified against experimental observations. A series of parameters were considered, including the number of transverse beams; the thickness, width and spacing of the steel strips at joint panels; and the axial compression ratio of columns. The results obtained from twenty specimens in terms of load response, cracking pattern, stress distribution, stiffness degradation and energy dissipation confirmed the effectiveness of the modified steel jacketing method. Significant differences among the roles of the parameters were revealed, and the reasons behind the differences were analyzed. Moreover, by means of significance analysis, the width and thickness of the steel strips were identified as the most influential parameters on the shear capacities of the joint panels with single- and double-sided transverse beams, respectively. Furthermore, based on the softened strut-and-tie model, a design approach for predicting the shear contribution of steel jackets in the presence of transverse beams was proposed for engineering applications. Full article

Trioctyl(alkyl)phosphonium chloride ionic liquids ([P_888n][Cl], n = 8, 14, and 16) were synthesized, characterized, and investigated for the extraction of Co, Ni, Mn, Mg, Zn, and Ca from chloride solutions. The three ionic liquids were very effective for the extraction of cobalt (over 95%) from solutions containing 1 g/L of Co(II) and 4 M HCl or NaCl. Equilibrium cobalt extraction was attained in less than 10 min at 25 °C using the most viscous ionic liquid [P₈₈₈₁₆][Cl]. Based on a speciation diagram for cobalt–chloride species and ultraviolet–visible spectrometric analysis of the phases, it was concluded that Co(II) extraction involved the extraction of the neutral species CoCl₂. Only at high chloride concentration, the anionic exchange mechanism involving $\mathrm{C}\mathrm{o}{\mathrm{C}\mathrm{l}}_4^{2-}$ was the most dominant. The stripping of the loaded ionic liquids can be carried out with water, and the stripped ionic liquids can be recycled up to five times maintaining their extraction effectiveness. In all of the conditions tested, the selectivity of [P_888n][Cl] ionic liquids for the extraction of cobalt over nickel was great, with a separation factor over 25,000 for 5M HCl solutions. Furthermore, very good selectivity for Co(II) over Mg(II) and Ca(II) extraction was also obtained. Conversely, Zn(II) can be selectively extracted over Co(II) and Mn(II) using only diluted [P₈₈₈₁₄][Cl]. Full article

Metabolic control is poor in East Africa for youth with type1 diabetes (T1D). Self-monitoring of blood glucose (SMBG) by fingerstick 2–3 times daily is routine care. This randomized controlled trial (RCT) will test the hypothesis that providing continuous glucose monitoring (CGM) to Ugandan youth with T1D will improve glucose time-in-range (TIR glucose 3.9–10.0 mmol/L) and be cost effective in this setting. Ugandan youth with T1D (n = 180, age 4–26 years) will be divided into four 12-month cohorts (August 2022–August 2027). Half will receive unblinded Freestyle Libre 2 Flash CGM for 12 months. For six months, control subjects received sufficient test strips for SMBG three times daily while wearing blinded Freestyle Libre Pro CGM (for endpoint assessment), and then they switch to unblinded CGM for six months. Everyone receives monthly diabetes education. The primary endpoints are as follows: (1) the six-month change from baseline in glucose TIR, unblinded CGM versus SMBG; (2) a cost analysis of CGM versus SMBG. The TIR hypothesis will be tested by linear mixed effects models. Cost analysis assumptions include direct material and indirect costs like hospitalizations, missed school/work, and diabetes complications. The study will inform T1D management guidelines in a low resource setting using evidence-based recommendations. Full article

This study examined associations between two strip-cropping innovations, cereal–legume (Mbili-Mbili) and legume–legume (doubled-up legume, DUL), and intra-household decision-making, labor allocation, and control over production benefits among smallholder farmers in Babati, northern Tanzania. Household survey data were collected from 157 households using a multi-stage cluster sampling approach, capturing variation by gender, age groups, and household characteristics. Across technologies, households were predominantly male-headed (91.7%), with men comprising 71.3% of respondents and managing 66.9% of trial plots. Decision-making on production, marketing, and income use was predominantly led by men, with joint decision-making accounting for approximately 24–32% of income-related decisions. Women contributed a larger share of field labor across both systems, providing 17.7% more labor than men under Mbili-Mbili and 29.7% more under DUL. Economically, Mbili-Mbili was associated with higher average net benefits (US$731 ha⁻¹) and benefit–cost ratios (2.5) than DUL (US$213 ha⁻¹; BCR = 0.7). More than half of Mbili-Mbili participants (53.3%) reported modifying the trial design, compared with 18.4% of DUL participants; Mbili-Mbili farmers trained more non-project farmers on average (4.0 vs. 0.9) and allocated larger areas for expansion (0.5 vs. 0.3 ha). Exploratory analysis suggested descriptive associations between productivity and economic outcomes and selected household characteristics, including labor availability and education. Overall, Mbili-Mbili exhibited stronger economic performance but higher labor requirements, with women contributing disproportionately to field operations under both technologies. These findings highlight the need for gender-responsive design, labor-saving options, and inclusive decision-making arrangements to support equitable and sustainable adoption of diversified strip-cropping innovations. Full article

Strengthening square reinforced concrete (RC) columns with full ultra-high-performance fiber-reinforced concrete (UHPFRC) jacketing is highly effective, but such complete wrapping is often impractical due to architectural or geometric constraints. Previous studies have not systematically examined the performance of partial-coverage UHPFRC patterns for these sections. This study numerically investigates the axial performance of square RC columns strengthened with strategically arranged UHPFRC elements—including horizontal shortcuts, vertical strips, and hybrid configurations—using finite element analysis in ABAQUS. Key parameters include jacket thickness, element dimensions, column height, and reinforcement details. Results show that a 10 mm full UHPFRC jacket more than doubles axial capacity (+105.9% for 800 mm columns), with significant gains in stiffness. Vertical strips enhance strength but reduce ductility; horizontal shortcuts improve post-peak stability; and hybrids offer a balanced response. With full jacketing, internal steel details have minimal impact on peak capacity, while column height chiefly influences energy dissipation. This work establishes that optimized partial UHPFRC layouts—specifically strips, shortcuts, and their combinations—can achieve tailored performance improvements, introducing a novel, practical, and material-efficient design strategy for strengthening square columns where full wrapping is not feasible. Full article

In this paper, aiming at the aging problem of rubber sealing strips in key parts of hydropower units under long-term load, this study proposes a quantitative aging-feature-extraction technique centered on the ratio of the short-axis length to the original diameter (b/D) of serviced rubber strips. Through a systematic approach combining theoretical analysis, numerical simulation, and measured data calculations, the research first derives from energy principles that the elastic modulus (E) and yield stress (σ_s) are key physical parameters characterizing rubber aging, reflecting the material’s energy storage capacity and irreversible deformation threshold, respectively. Based on this, a radial compression simulation model of rubber strips is established, focusing on the cross-sectional deformation laws under 25% and 30% compression ratios in serviced conditions. It is found that the short-axis diameter ratio b/D exhibits a significant linear relationship with the dimensionless yield stress (σ_s/E), and a quadratic relationship with the dimensionless unit-length reaction force (F/ED). Using measured data, fluororubber (FKM) and nitrile rubber (NBR) specimens after 17 years of service are selected for radial compression experiments to extract the elastic modulus. The calculated results are compared with elasticity modulus estimates based on hardness empirical formulas (Gent’s and Qi’s formulas), showing consistency, particularly with Qi’s formula for NBR. This method enables rapid and accurate assessment of rubber aging, demonstrating the effectiveness and practicality of using b/D as a feature parameter. The study provides a quantitative and convenient tool for condition monitoring and life prediction of industrial equipment seals, especially suitable for the operation and maintenance of rubber components in complex environments such as hydropower units. Full article

The effects of storage time on the characteristics of starch in spicy strips were investigated. Techniques including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) were employed to analyze the gelatinization properties, thermal characteristics, crystal structure, moisture distribution, and quality changes of spicy strips under different storage periods (0, 60, 120, and 180 days). The results demonstrated that prolonged storage led to a significant decrease in peak viscosity and an increase in setback value, indicating enhanced starch retrogradation. DSC analysis revealed a continuous increase in enthalpy change (ΔH), confirming the formation of more ordered double-helix structures over time. TGA revealed a shift in thermal degradation profiles, indicating changes in component interactions and moisture-binding capacity over storage. XRD patterns showed a clear transition from A-type to V-type crystals and finally to an amorphous state after 180 days. Consequently, solubility, swelling power, and amylose leaching were markedly inhibited, while the retrogradation rate of amylopectin became dominant during long-term storage. These findings provide insights into starch retrogradation mechanisms in complex snack matrices and offer guidance on mitigating quality deterioration during the shelf life of spicy strips. Full article

Background: This study evaluates short-term skin compatibility and biophysical changes in new cosmetic preparations containing PRF and EGF, conducted through in vivo studies. Material and Methods: The study involved 20 healthy volunteers (aged 20–40) who received three identically packaged creams to be applied for a period of four weeks to specific facial areas: formulation 1: base formulation (control); formulation 2: base formulation human epidermal growth factor (EGF) loaded; and formulation 3: base formulation platelet-rich fibrin (PRF) loaded. Skin assessments were conducted at baseline (week 0) and at weeks 1, 2, and 4. Transepidermal water loss (TEWL), skin hydration using corneometry to determine the moisture content of the stratum corneum, skin elasticity using a cutometer to measure the skin’s ability to return to its original state after deformation, and dermal bioavailability were measured. EGF concentration in the stratum corneum will be measured using the tape-stripping method followed by HPLC (high-performance liquid chromatography) analysis. Results: A significant decrease in TEWL was observed for all tested formulations (24%, 37%, and 34%, for formulations 1, 2, and 3, respectively), indicating improved skin barrier function. Formulation 3 showed the highest increase in skin hydration (by 95%), followed by formulation 2. Both formulations 2 and 3 demonstrated improvements in skin elasticity, with formulation 3 showing the greatest enhancement. EGF concentration in the stratum corneum increased over the four-week period, reaching equilibrium with the product concentration by week four. Conclusions: The in vivo instrumental compatibility studies confirmed that the new cosmetic formulations were well tolerated and associated with short-term improvement in selected skin parameters. Full article

Programmable photonic integrated circuits implement optical switching and processing by interconnecting reconfigurable 2 × 2 cells in mesh topologies. Directional couplers are widely used in these cells, often combined with phase-shifting mechanisms to enable tunability. However, conventional directional couplers in dense meshes typically require submicron gaps and tight etching tolerances, which increase sensitivity to fabrication variations and can introduce excess loss and variability. In addition, interconnected waveguides (e.g., S-bends and crossings) increase layout complexity, footprint, and bending-related penalties, while thermo-optic control may introduce power consumption and thermal crosstalk. Here, we propose a shallow-rib strip directional coupler in hydrogenated amorphous silicon (a-Si:H) for 1 µm × 1 µm multimode waveguides. The proposed geometry enables efficient coupling for waveguide separations ≥ 1 µm by shifting the coupling control from the lateral gap to the slab height, allowing smoother transitions and a relaxed fabrication flow. The analysis combines coupled-mode theory and beam propagation method simulations. As an application example, the layout of a 4 × 4 thermo-optically reconfigurable switching matrix is designed and simulated using 2 × 2 shallow-rib strip coupler cells. Full article

Early detection of cancer biomarkers in blood is critical for improving patient outcomes; however, conventional immunoassays often rely on complex instrumentation and are not well suited for point-of-care testing or multiplexed analysis. Herein, we present a dual-mode colorimetric–surface-enhanced Raman scattering (SERS) lateral flow immunoassay (LFIA) platform for multiplexed detection of cancer biomarkers, employing elongated rod-shaped silver nanoshells (ERNSs) as SERS nanotags. The ERNS features a rough Ag shell with internally incorporated Raman labeling compounds (RLCs), enabling plasmonic extinction for visual readout and strong SERS signals for quantitative analysis while preserving the external metal surfaces for efficient antibody conjugation. Leveraging these advantages, a multiplex LFIA capable of simultaneously detecting prostate-specific antigen (PSA) and carbohydrate antigen 19-9 (CA19-9) on a single strip was successfully demonstrated. Visual inspection enabled rapid discrimination of samples at or near clinically relevant cut-off levels, while Raman analysis achieved limits of detection of 8.0 × 10⁻³ ng/mL for PSA and 5.4 × 10⁻² U/mL for CA19-9, corresponding to approximately 500-fold and 685-fold lower concentrations than their respective clinical thresholds. This ERNS-based colorimetric–SERS LFIA integrates rapid screening and highly sensitive quantification within a single platform and offers a versatile nanoprobe design strategy for multiplex biomarker detection and liquid biopsy-based diagnostic applications, with potential relevance to point-of-care settings. Full article