Search Results (4,869)

In the dry–hot valley region of Southwest China, water infiltration exhibits temporal variations due to the combined effects of land use type and the dramatic seasonal dry–wet cycle. To accurately compare and predict the infiltration characteristics, soil water infiltration processes and cumulative infiltration were quantified for five typical land uses—traditional corn (TC), plum orchard (PO), pine forest (PF), grassland (GL), and abandoned cropland (AC)—in a dry–hot valley region during both the rainy (July) and dry (November) seasons using a Mini Disk Infiltrometer (MDI). These data were then statistically analyzed using the Kostiakov, Philip, and Horton models. The results showed that the mean infiltration rate and cumulative infiltration during the rainy season were 1.34 times and 1.31 times higher than in the dry season, respectively. The water infiltration rate and cumulative infiltration for the five land uses generally followed the order of PF > GL/TC > PO/AC during both rainy and dry seasons. The model parameters related to the initial infiltration capability (Kostiakov parameter, a) and the steady infiltration capability (Philip parameter, A; and the Horton parameter, f_c) during the rainy season were all greater than those in the dry season. Compared to the Kostiakov and Horton models, the Philip model achieved the highest mean Nash–Sutcliffe efficiency (NSE) values in fitting soil water infiltration processes, the lowest mean relative error (MRE) values, and the highest determination coefficient values (R²) in predicting the cumulative infiltration, with relatively little difference between the two seasons. These results indicate that PF, GL, and TC exhibit superior soil water infiltration capabilities compared to other land uses during both the rainy and dry seasons. The Philip model is more suitable for estimating soil infiltration capacity in the dry–hot valley region during both seasons. Identification of the superior land use types and accuracy determination of the water infiltration model can help guide effective water conservation and vegetation restoration initiatives in the dry–hot valley region of Southwest China. Full article

The article derives sufficient conditions under which the normalized Rabotnov function becomes q-close-to-convex relative to specific starlike functions on the open unit disk. To enhance the impact of our results, we include some consequences derived from the main theorems, along with graphical illustrations. The starlikeness of the Rabotnov function with respect to different aspects also falls within the scope of this study. Full article

Chronic ulcers are characterized by impaired tissue repair and frequently harbor antimicrobial-resistant microorganisms, worsening clinical outcomes. The objective of this study is to identify microbial agents in chronic ulcers treated at the Lauro de Souza Lima Institute Wound Care Outpatient Clinic and to evaluate their antimicrobial susceptibility profiles and β-lactamase production. Samples (swab and biopsy) from patients treated at the Lauro de Souza Lima Institute were analyzed. Susceptibility was assessed by disk diffusion. ESBL and AmpC production were confirmed by PCR targeting blaTEM, blaSHV, blaCTX-M1, and blaCMY-2. In Staphylococcus spp., oxacillin and clindamycin resistance were evaluated and confirmed by mecA and ermAC. From 33 patients (mean age 63.4 years), 116 isolates were obtained, mainly Pseudomonas aeruginosa (27%), Proteus mirabilis (18%), and Staphylococcus aureus (13%). P. aeruginosa showed high resistance, with 48% MDR and 29% PDR. Among Enterobacterales, 19% were ESBL producers and 17% AmpC, with 56% carrying blaCMY-2. In Staphylococcus, 33% were oxacillin-resistant and 50% expressed MLSb phenotype. P. aeruginosa was identified as the most prevalent pathogen, with frequent MDR/PDR phenotypes. Resistance genes exhibited a discrepancy between genotypic and phenotypic profiles, suggesting the presence of unexpressed resistance that may be inducible during treatment. Full article

Temporomandibular disorders (TMDs) are a group of musculoskeletal conditions characterized by pain, restricted mandibular movement, and joint sounds, which may significantly impair quality of life. Among conservative treatment modalities, low-level laser therapy (LLLT) has gained increasing attention due to its noninvasive nature and its documented analgesic and anti-inflammatory effects. Despite growing evidence supporting the clinical effectiveness of LLLT in the management of TMD-related pain and dysfunction, there is still no consensus regarding the optimal energy density parameters to achieve the most favorable therapeutic outcomes. Therefore, the primary objective of this randomized clinical trial was to determine the optimal energy density of low-level laser therapy. This clinical study evaluated the effects of LLLT applied at different energy densities in patients diagnosed with disk displacement with reduction (DDwR) and myofascial pain. A total of 100 patients were divided into two diagnostic groups, each divided into three subgroups: 940 nm, 1.5 W, 90 J; 940 nm, 3 W, 180 J; and a soft diet group. Laser treatment was performed three times per week for three weeks, for a total of nine sessions. Pain intensity, mandibular movements, and joint sounds were assessed at baseline and at one and six months. Comparable and favorable clinical improvements were achieved in both the laser therapy groups and the soft diet group. The 1.5 W-treated group showed the most significant VAS (visual analog scale) parameter reduction at 6 months. Laser treatment outcomes can be summarized as follows: low-level laser therapy was associated with clinical improvement; however, similar positive outcomes were also observed in the soft diet group. These findings indicate that further controlled studies are needed to better clarify the specific role of laser therapy in the management of temporomandibular disorders. Full article

Wilsonosaura Lehr, Moravec, Von May, 2020, was described as a monotypic genus from central Peru, based on genetic and morphological characters. This genus is easily distinguished from other lizards in the gymnophthalmid subfamily Cercosaurini, except for Proctoporus, by the presence of an undivided translucent lower palpebral disk, weakly keeled dorsal scales, and the absence of preanal pores. Morphological synapomorphies to distinguish Wilsonosaura and Proctoporus have not been identified. Consequently, differentiation of both genera continues to require molecular analysis. We describe a new species of Wilsonosaura based on morphological and DNA sequence data and extend the geographic distribution of this genus by 88.53 km to the southeast of Ayacucho, Peru, from the nearest known record to date. The new species is known only from the Ayacucho Department, Huamanga and Huanta Provinces, in the eastern Andes, between 2674 and 2800 m a.s.l., where it inhabits humid areas along riverbanks, urban areas, and farming areas and can be found under rocks, logs, and urban buildings. Wilsonosaura sp. nov. can be distinguished from W. josyi by the absence of fusion of the first superciliary and first supraocular scales, a lower count of scales in the mid-body, a higher scale row count on the side of the neck, a smaller size, and a different coloration pattern. Full article

The worldwide rise in antimicrobial resistance, along with the ongoing prevalence of cancer, underscores the pressing need for novel, safe, and multifunctional therapeutic candidates. Medicinal plants continue to serve as a valuable source of chemically diverse bioactive molecules that modulate multiple biological targets. In this investigation, the preliminary screening of the antibacterial and anticancer activities of an ethanolic extract of Alhagi maurorum (A. maurorum) was comprehensively evaluated using integrated chemical characterization, in vitro bioassays, and in silico approaches. A liquid chromatography–mass spectrometry (LC-MS) analysis demonstrated a rich phytochemical profile including glucosinolates, phenolic acids, gallotannins, fatty acids, alkaloids, carotenoid derivatives, and 2-hexyldecanoic acid-associated constituents. Antibacterial efficacy was assessed by disk diffusion and minimum inhibitory concentration (MIC) testing against Escherichia coli (E. coli ) and Bacillus cereus (B. cereus), with the extract producing inhibition zones similar to those observed with streptomycin. Anticancer effects were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays with MCF-7 breast carcinoma cells and Hs27 normal fibroblasts over 24, 48, and 72 h., revealing a time-dependent, selective decrease in malignant cell viability with relatively limited toxicity towards normal cells. Induction of apoptosis was further verified by propidium iodide (PI) staining. A molecular docking analysis highlighted 2-hexyldecanoic acid as the principal active compound, with a strong binding affinity for critical bacterial targets (GyrA, GyrB, and RpoB). In silico toxicity and ADME (absorption, distribution, metabolism, and excretion) assessments indicated favorable drug-like properties, good gastrointestinal uptake, and acceptable safety profiles. Altogether, these results provide combined experimental and computational support for A. maurorum as a promising source of dual-purpose antibacterial and anticancer agents and lay a mechanistic foundation for subsequent preclinical studies. Full article

Complex functions which are harmonic in the unit disk can be represented by the sum of a power series and the conjugate of a power series. In geometric theory, classes of functions with some condition imposed on the coefficients of these power series have often been considered. In particular, Silverman introduced and studied harmonic functions with various coefficients or negative coefficients. In the present paper we introduce and study harmonic functions with fixed argument of coefficients. We should notice here that there is a certain symmetry between these problems and the analogous ones of the theory of analytic functions, i.e., problems considered in the geometric theory of analytic functions are adapted to the theory of harmonic functions. Full article

Lubricant additive optimisation, such as using an Organic Friction Modifier (OFM), often relies on empirical methods because the role of interfacial energetics in boundary lubrication remains uncertain. This study explores how interfacial energy interactions affect the tribological performance of glycerol monooleate (GMO)–polyalphaolefin-4 (PAO4) blends using ball-on-disk friction and wear tests. The 7 wt% GMO blend showed the best results, with friction reduced by about 4 times and the wear scar diameter by nearly 6 times compared to neat PAO4. Film-thickness estimates indicate that all tests operated within the boundary-to-mixed lubrication regime, suggesting that friction reduction is associated with interfacial interactions rather than hydrodynamic film formation. The Owens–Wendt–Kaelble surface energy analysis reveals that increasing GMO concentration shifts the lubricant’s dispersive–polar balance, with the 7 wt% formulation exhibiting dispersive–polar characteristics closer to those of the steel substrate. Low friction persisted as sliding velocity increased, and rupture-threshold analysis is consistent with improved tribological response under increasing load and sliding conditions. These findings suggest that the favourable tribological response observed for the investigated formulations may be associated with balanced interfacial energetic characteristics, particularly between dispersive and polar interactions. The observed friction and wear behaviour under increasing sliding conditions is interpreted in terms of friction and wear responses under boundary-dominated conditions, rather than through direct structural characterisation of boundary films. These trends are interpreted in relation to changes in dispersive and polar interactions at the interface. The results provide an interpretive framework for designing OFM systems that may be relevant to high-shear environments, including applications such as hydrogen internal combustion engines. Full article

In this paper, we introduce two novel subclasses, ${\mathcal{MS}}_{\kappa }^{*}(\delta ,\beta ,\mu )$ and ${\mathcal{NS}}_{\kappa }^{*}\left(\phi \right)$, of analytic and bi-univalent functions associated with generalized Mathieu-type power series in the open unit disk. By employing coefficient-based techniques, we derive new bounds for the initial Taylor–Maclaurin coefficients and the Fekete–Szegö functional for functions belonging to these subclasses. The obtained results contribute to the ongoing development of coefficient problems in geometric function theory and provide a unified framework that extends several known results in the literature. Additionally, we present a range of special cases that recover previously studied function classes, thereby highlighting the flexibility and applicability of the proposed approach. Full article

This paper presents a comprehensive investigation of the effects of atmospheric plasma treatment (APT) on the surface morphology, microhardness, chemical composition, and tribological performance of alloy steel used in railway applications. A novel mathematical model is proposed to describe the dependence of the maximum surface asperity height on the APT parameters and material properties. Experimental validation was performed using a series of alloy steel specimens treated under controlled APT conditions. The surfaces were characterized by roughness measurements, microhardness testing, scanning electron microscopy, and energy-dispersive spectroscopy. Tribological properties were evaluated under dry sliding conditions using ball-on-disk tests with steel counterbodies (grades 1.3529 and 1.3505). Tribological testing showed that APT leads to a 6–7% reduction in the steady-state friction coefficient, eliminates the long running-in stage, and improves stability by lowering the coefficient of variation by up to 43%. Overall, this study demonstrates that APT provides a dual benefit: improving tribological performance through surface smoothing and stabilization of the friction regime, and preserving the mechanical and chemical integrity of the material. Full article

Wire Arc Additive Manufacturing (WAAM) has emerged as a cost-effective and high-deposition-rate technique for fabricating large-scale metallic components; however, the complex thermal history inherent to the process leads to heterogeneous microstructures that can significantly influence tribological performance. In this study, the dry sliding wear behavior of WAAM-fabricated austenitic stainless steel 308L (SS308L) was systematically investigated using a pin-on-disk configuration. The influence of applied normal load (1.5–15 N) and sliding speed (0.03–0.229 m/s) on wear volume, specific wear rate, coefficient of friction (COF), and tangential force was evaluated. Optical microstructural observations indicated features consistent with a ferritic–austenitic solidification structure, including regions resembling polygonal ferrite, Widmanstätten ferrite, and austenitic dendritic morphologies. Wear results showed that wear volume and cross-sectional area increased monotonically with increasing load, while the effect of sliding speed was comparatively less significant. The specific wear rate remained on the order of 10⁻⁴ mm³/N·m with minor variations across test conditions. The COF decreased with increasing load up to 10 N, followed by a speed-dependent response at higher loads. The findings demonstrate that load is the dominant factor governing wear behavior in WAAM SS308L, while microstructural heterogeneity may contribute to frictional stability and wear resistance. This study provides valuable insight into the structure–tribology relationship of WAAM stainless steels and supports the optimization of process parameters for wear-critical applications. Full article

Background: The emergence and spread of urinary carbapenem-resistant organisms (CROs) are a major public health concern, particularly in Sri Lanka. Therefore, we aimed to detect and genotypically characterize CROs in urinary tract infections (UTIs) and their clinical outcomes. Methods: Urinary CROs were collected from two hospitals in Sri Lanka from January to December, 2023. Among 7640 urine samples, 100 CROs were identified by disk diffusion method, and 99 were detected by BD Pheonix^TM automated system. The presence of eight carbapenemase genes; bla_KPC, bla_NDM, bla_VIM, bla_IMP, bla_OXA-23, bla_OXA-48, bla_OXA-51, and bla_OXA-58, among 97 CROs was detected by a multiplex PCR kit. Results: Out of 99 urinary CROs, K. pneumoniae (33.3%; n = 33/97) was the most common species. Among the 97 isolates tested by PCR, a single carbapenemase gene was detected in 35.05% (34/97), while two or more genes co-occurred in 39.18% (38/97). The most frequently identified gene was bla_OXA-51 (47.4%), followed by bla_OXA-58 (41.2%). Most patients (95.74%; n = 90/97) showed clinical improvement within seven days of treatment. Among the 93 patients discharged and followed for three months, 74.20% (n = 69/93) experienced at least one mild UTI recurrence. A total of 10 patients died during the study period. Of which, four (40%) during hospitalization and six (60%) during follow-up, though none of the deaths were attributed to UTIs. Conclusions: K. pneumoniae, showed the highest carbapenemase gene diversity. Recurrent UTIs were observed during the follow-up period. Continuous surveillance and implementation of targeted infection control programs are needed to minimize further emergence and spread of carbapenemase genes. Full article

Background/Objectives: Provisional restorations are widely used in fixed prosthodontics, and polymethyl methacrylate (PMMA) remains one of the most commonly used materials. Discoloration during intraoral service may compromise their esthetic acceptability. Graphene-reinforced PMMA has been introduced to improve material performance, although its color stability under simulated oral conditions remains insufficiently characterized. This study aimed to compare the color changes in conventional PMMA and graphene-reinforced PMMA after exposure to salivary pH variations and coffee, combined with simulated masticatory movements. Methods: Forty PMMA and forty graphene-reinforced PMMA (G-CAM) disk-shaped specimens (8 mm × 2 mm) were allocated to eight original experimental groups according to material and condition (pH 7, coffee, pH change, or pH change plus coffee), under simulated chewing movements. Color was recorded before and after the procedures using an imaging system, and values were converted into CIELAB coordinates. Statistical analysis included Wilcoxon, Mann–Whitney U, Kruskal–Wallis, and Bonferroni-adjusted pairwise comparisons, with a significance level set at p < 0.05. Results: Both materials exhibited measurable color changes after the experimental procedures. PMMA showed higher median ΔE values than graphene-reinforced PMMA in the coffee and pH change plus coffee conditions, where the differences between materials were statistically significant. The highest color changes were observed in PMMA exposed to coffee and to the combined pH change plus coffee protocol, exceeding the clinical acceptability threshold. Conclusions: Graphene-reinforced PMMA (G-CAM) showed greater color stability than conventional PMMA, although neither material can be considered completely color stable. The greatest color variation was observed in the groups exposed to pH change followed by coffee immersion, as reflected by ΔE values. Full article

The ionosphere is the ionized region of the atmosphere, extending roughly from 60 km to 1000 km in altitude. During flares, the near-Earth space is subjected to high-energy X-ray and EUV (extreme ultraviolet radiation) radiation, which also impacts the ionosphere. The changes in the ionospheric parameters measured by ionosondes, namely the f_min (minimum frequency) and foF2 (F2-layer ordinary-mode critical frequency) values, were examined during solar flares that occurred in geomagnetically quiet conditions (Dst (Disturbance Storm Time index) > −40 nT, Kp (planetary K-index) < 4). The necessary data were obtained by manually evaluating ionograms recorded by the Czech DPS4D ionosonde at Pruhonice (PQ052). The degree of variation was compared to quiet reference days, allowing for the determination of the deviations in the required values (df_min, dfoF2). The time series of the deviations were investigated. Furthermore, the relationship between the deviations and a “geoeffectiveness” parameter of the solar flare was also examined. The X-ray flux, the solar zenith angle of the station at the time of the event, and the position of the flare on the solar disk were also taken into account for the determination of the “geoeffectiveness” parameter. A positive correlation was observed between df_min and the geoeffectiveness parameter of the flare, which was more significant than the correlation between the dfoF2 and the geoeffectiveness parameter. Full article

HT250 grey cast iron is a material of significance in the manufacture of precision machine tool guideways. The performance of guideways is significantly affected by the wear resistance of the machined surface. The present paper studies comparative grinding experiments conducted on HT250 using CBN and SiC wheels. The aim was to investigate the potential benefits of CBN grinding in enhancing surface wear resistance and to illuminate the underlying mechanisms. The results of these experiments demonstrate that, compared with SiC grinding, CBN grinding produces guideway specimens’ subsurface layer with finer grains (refined by approximately 15%) and notably higher microhardness (peak value of 382 HV). These microstructural improvements directly enhance the wear resistance of the ground surface. Within the tested parameter range, the optimal wear-resistant surfaces were obtained at a grinding speed of v_s = 30 m/s, a feed rate of v_f = 2000 mm/min, and a depth of cut of a_p = 6 μm. Under these conditions, surface roughness is better than R_a 0.4 μm, and surface microhardness achieves its maximum value. The wear tests were conducted using a ball-on-disk configuration under room temperature, oil lubrication, and applied loads ranging from 20 N to 80 N. The results show that, under the same loading and wear testing conditions, the wear depth of specimens machined with CBN wheels is reduced to 80–50% of that of specimens processed with conventional SiC wheels. Full article