Search Results (1,548)

This paper introduces a novel fractional-order model using the Caputo derivative operator to investigate the virus dynamics of adaptive immune responses. Two infection routes, namely cell-to-cell and virus-to-cell transmissions, are incorporated into the dynamics. Our research establishes the existence and uniqueness of positive and bounded solutions through the application of the generalized mean-value theorem and Banach fixed-point theory methods. The fractional-order model is shown to be Ulam–Hyers stable, ensuring the model’s resilience to small errors. By employing the normalized forward sensitivity method, we identify critical parameters that profoundly influence the transmission dynamics of the fractional-order virus model. Additionally, the framework of optimal control theory is used to explore the characterization of optimal adaptive immune responses, encompassing antibodies and cytotoxic T lymphocytes (CTL). To assess the influence of memory effects, we utilize the generalized forward–backward sweep technique to simulate the fractional-order virus dynamics. This study contributes to the existing body of knowledge by providing insights into how the interaction between virus-to-cell and cell-to-cell dynamics within the host is affected by memory effects in the presence of optimal control, reinforcing the invaluable synergy between fractional calculus and optimal control theory in modeling within-host virus dynamics, and paving the way for potential control strategies rooted in adaptive immunity and fractional-order modeling. Full article

This pilot study investigated the metabolic responses of five selected bacteria to physiological stress. Surface-enhanced Raman spectroscopy was used to analyze spectral changes associated with the release of adenine, a key metabolite indicative of stress conditions. Laboratory-synthesized spherical silver and gold nanoparticles, which remained stable over an extended period, were employed as enhanced surfaces. Bacterial cultures were analyzed under standard conditions and in the presence of a selected stressor—demineralized water—inducing osmotic stress. The results showed that the adenine signal originated from metabolites released into the surrounding environment rather than directly from the bacterial cell wall. The study confirms the suitability of these cost-effective and easily synthesized stable nanoparticles for the qualitative detection of bacterial metabolites using a commercially available Raman instrument. Full article

Nowadays, there is special interest in promoting the consumption of ancestral crops and minimally processed foods with high nutritional value. However, besides nutritional issues, safety assessments must be addressed. This study aimed to evaluate mycotoxin contamination in five minimally processed traditional Ecuadorian foods: ochratoxin A (OTA), fumonisin B₁ (FB₁), and aflatoxins (AFs) in brown rice, lupin, and quinoa; OTA, FB₁, and deoxynivalenol (DON) in whole-wheat flour; and OTA and AFs in peanuts. Samples (45 samples of peanuts and whole-wheat flour, 47 of brown rice, 46 of quinoa, and 36 of lupin) were collected from local markets and supermarkets in the three most populated cities in Ecuador. Mycotoxins were determined by RP-HPLC with fluorescence and detection. Results were compared with the maximum permitted levels (MPLs) of European Regulation 2023/915/EC. Overall contamination reached up to 59.8% of the analyzed samples (38.4% with one mycotoxin and 21.5% with co-occurrence). OTA was the most prevalent mycotoxin (in 82.6% of quinoa, 76.7% of whole-wheat flour, 53.3% of peanuts, 48.6% of lupin, and 25.5% of brown rice), and a modest number of quinoa (17%) and lupin (5.7%) samples surpassed the MPLs. DON was found in 82.2% of whole-wheat flour (28.9% > MPL). FB₁ was detected in above 25% of brown rice and whole-wheat flour and in 9% of the quinoa samples. FB₁ levels were above the MPLs only for whole-wheat flour (17.8%). AFB₁ and AFG₁ showed similar prevalence (about 6.5 and 8.5%, respectively) in quinoa and rice and about 27% in peanuts. Overall, these findings underscore the importance of enhancing fungal control in the pre- and post-harvest stages of these foods, which are recognized for their high nutritional value and ancestral worth; consequently, the results present key issues related to healthy diet promotion and food sovereignty. This study provides compelling insights into mycotoxin occurrence in minimally processed Ecuadorian foods and highlights the need for further exposure assessments by combining population consumption data. Full article

Ochratoxin A (OTA), as a mycotoxin, can contaminate a variety of feeds and foods. Existing studies have shown that the main toxicity of OTA to organisms is nephrotoxicity, but the toxic mechanism to other organs is still worthy of further study. Whether OTA causes intestinal damage through the necroptosis pathway mediated by RIPK1/RIPK3/MLKL remains to be elucidated. Astaxanthin (AST), a feed additive with strong antioxidant properties, was used as an antidote to evaluate the alleviation effect on OTA-induced intestinal injury and the underlying mechanism in this research. Chickens are the most sensitive animals to OTA except pigs. Therefore, 70 white-feathered chickens (n = 15) and Chicken Small Intestinal Epithelial Cells (CSIECs) were used as experimental subjects. Experimental models were established by single or combined exposure of OTA (1.0 mg/kg on chickens for 21 d; 2 μM on CSIEC for 24 h) and AST (100 mg/kg on chickens for 21 d; 40 μM on CSIEC for 24 h). In this study, AST significantly ameliorated OTA-induced intestinal damage by restoring the expression of tight junction proteins (Occludin-1, Claudin-1, and ZO-1), attenuating severe histopathological alterations, mitigating the inflammatory response (elevated pro-inflammatory cytokines and reduced anti-inflammatory mediators), and suppressing necroptosis through downregulation of RIPK1, RIPK3 and MLKL expression. Combined evidence from animal experiments and cell culture experiments demonstrated that AST alleviated the necroptosis and inflammation caused by OTA in CSIECs and the intestine of chickens through the RIPK1/RIPK3/MLKL signaling pathway, thereby reducing the damage caused by OTA. Full article

In this study, the aim was to determine the levels of aflatoxins and ochratoxin A (OTA) in baby food consumed in Hatay using fluorescence-detector HPLC (HPLC-FLD) and to reveal the health risks that may occur in babies through consumption of these foods. To determine the dietary intake and to reveal the health risk assessment, the estimated daily intake (EDI) for all mycotoxins, the margin of exposure (MOE) for aflatoxin B₁ (AFB₁), aflatoxin M₁ (AFM₁) and OTA, the hazard index (HI) and the consumption-related hepatocellular cancer risk for AFM₁ were calculated. It was reported that 11.5% and 8.2% of the analyzed samples exceeded the legal limit set for AFB₁ and OTA, respectively. However, it was found that AFM₁ concentrations in all samples did not exceed the legal limit. Based on the estimated consumption amounts of the baby foods, the HI values calculated for AFM₁ were below 1, and the MOE values calculated for AFB₁ and AFM₁ were above 10.000, indicating that the consumption of baby foods does not pose a risk regarding AFB₁ and AFM₁ for babies. However, it was determined in all other products, except for toddler formula, that the MOE values calculated for OTA were below 10.000, indicating that their consumption may pose serious health problems in babies. Full article

Mycotoxins are toxic secondary metabolites produced by various fungi that contaminate livestock feed, posing serious threats to animal health, productivity, and food safety. Although historical research has often examined individual mycotoxins in isolation, real-world conditions typically involve the simultaneous presence of multiple mycotoxins, resulting in additive or synergistic toxic effects that are often more severe than those observed with single toxin exposures. This review comprehensively synthesizes recent findings on multi-mycotoxin contamination in livestock feed, highlighting their physiological effects, mechanisms of action, and implications for regulatory frameworks. Multi-mycotoxin interactions exacerbate oxidative stress, immune suppression, impaired reproduction, and organ damage across species, leading to reduced growth performance, decreased milk and egg production, compromised carcass and wool quality, and increased mortality rates. A major concern is that current international regulatory standards mainly address individual mycotoxins, overlooking the compounded risks of co-occurrence. Global surveillance studies consistently reveal high prevalence rates of mycotoxin mixtures in feedstuffs, especially combinations involving DON, ZEN, AFB₁, FB₁, and OTA. Understanding these interactions and their underlying cellular mechanisms is critical for improving risk assessment models, formulating integrated mitigation strategies, and safeguarding both livestock productivity and human food security. Full article

This study presents transistor-level simulation results for a novel memristor emulator circuit. The design incorporates an inverter and a current-mode-controlled operational transconductance amplifier to stabilize the output voltage. Transient performance is evaluated across a 20 MHz to 100 MHz frequency range. Simulations using 0.18 μm TSMC technology confirm the circuit’s functionality, demonstrating a power consumption of 0.1 mW at a 1.2 V supply. The memristor model’s reliability is verified through corner simulations, along with Monte Carlo and temperature variation tests. Furthermore, the emulator is applied in a Memristive Integrate-and-Fire neuron circuit, a CMOS-based system that replicates biological neuron behavior for spike generation, enabling ultra-low-power computing and advanced processing in retinal prosthesis applications. Full article

Background: Proximal tibial fractures can lead to post-traumatic osteoarthritis (PTOA), and subsequent total knee arthroplasty (TKA) in such patients is associated with elevated complication rates. A two-stage approach, involving the elective removal of osteosynthetic hardware prior to TKA, is recommended. The utility of microbiological sampling from macroscopically unremarkable tissue during TKA implantation remains controversial. Objective: To retrospectively evaluate the rate of periprosthetic joint infection (PJI) following TKA after PTOA and to assess the potential benefit of intraoperative microbiological sampling. The secondary objective was to evaluate the presence of prior colonization in osteosynthetic hardware among the affected cases. Patients and Methods: A retrospective screening of the hospital database was conducted between 2008 and 2022, including only AO/OTA type 41-B and 41-C fractures. Patients were assigned to a sampling group (with microbiological sampling during TKA) or a control group (without sampling). All patients received structured follow-up to assess postoperative complications. Results: A total of 40 patients met the screening criteria. In the sampling group (n = 29), 17.24% required surgical revision, and the rate of PJI was 3.45%. In the control group (n = 11), 18.14% underwent revision surgery, with a PJI rate of 9.09%. The average follow-up period was 4.35 years (range 2–11.6 years). Discussion: TKA in patients with PTOA is associated with a heightened risk of complications. A noteworthy possible correlation between systematic microbiological sampling and reduced PJI incidence was observed. While the small sample size limits definitive conclusions regarding causality, the findings support the potential value of consistent intraoperative sampling. Full article

To clarify the current status of physical assessment education in Japan, this study analyzed publicly available syllabi from nursing universities. Syllabi from 299 member universities of the Japan Association of Nursing Universities were analyzed, and data on course classification methods, learning content, and practice methods were tabulated. The Body System Approach was the most common classification (used by 244 universities). Implementation rates were high for core systems like the respiratory system (98.0%) and cardiovascular system (95.2%), but lower for others, such as the otolaryngology system (41.5%). The use of simulation was noted in 21.4% of courses, and in 71.0% of syllabi, the role of the patient in practice exercises was not described. A discrepancy exists between the implemented content and the Model Core Curriculum for Nursing Education, which includes a wider range of systems. Furthermore, few syllabi described specific teaching methods, indicating that future curriculum revisions will require re-evaluation to ensure educational quality. Full article

Some additives currently used to enhance drilling mud’s rheological qualities have a substantial economic impact on society. Carboxymethyl cellulose (CMC) and calcium carbonate (CaCO₃) are currently imported. Food crops have influences on food security; hence, this research explored the potential of utilizing cow bone powder (CBP), a bio-waste product and a renewable resource, as an environmentally friendly fluid-loss additive for drilling applications, in comparison with CaCO₃. Both samples (CBP and CaCO₃) were evaluated to determine the most efficient powder sizes (coarse, medium, and fine powder), concentrations (5–15 g), and aging conditions (before or after aging) that would offer improved rheological and fluid-loss control. The results obtained showed that CBP had a significant impact on mud rheology when compared to CaCO₃. Decreasing the particle size (coarse to fine particles) and increasing the concentration from 5 to 15 g positively impacted mud rheology. Among all the conditions analyzed, fine-particle CBP with a 15 g concentration produced the best characteristics, including in the apparent viscosity (37 cP), plastic viscosity (29 cP), and yield point (25.5 lb/100 ft²), and a gel strength of 16 lb/100 ft² (10 s) and 28 lb/100 ft² (10 min). The filtration control ability of CaCO₃ was observed to be better than that of the coarse and medium CBP particle sizes; however, fine-particle-size CBP demonstrated a 6.1% and 34.6% fluid-loss reduction at 10 g and 15 g concentrations when compared to respective amounts of CaCO₃. The thermal behavior of the Mud Samples demonstrated that it positively impacted rheology before aging. In contrast, after aging, it exhibited a negative effect where samples grew more viscous and exceeded the API standard range for mud properties. Therefore, CBP’s excellent rheological and fluid-loss control ability makes it a potential, sustainable, and economically viable alternative to conventional materials. This superior performance enhances the thinning properties of drilling muds in stationary and circulating conditions. Full article

The aging process involves a decline in certain cognitive abilities. Cognitive aging progresses more quickly with obesity and more slowly with exercise and fasting. All of these conditions have strong impacts on white adipose tissue, which suggests that this tissue may play a pivotal role in the progression of cognitive aging. Brain-derived neurotrophic factor (BDNF), a neurotrophin indispensable for maintaining brain functions, becomes insufficient with age. Obesity also decreases the BDNF level in the hippocampus. This deficiency not only results in cognitive impairment but increases susceptibility to obesity. Both exercise and fasting increase the BDNF level in the hippocampus. Our study demonstrates that the chemokine ligand CX3CL1 in white adipose tissue is involved in the regulation of the BDNF level in the hippocampus. Aging reduces CX3CL1 expression, interfering with the mechanisms. Other studies have suggested that obesity increases adipose CX3CL1 expression; however, CX3CL1 augmented under obese condition may not contribute to the promotion of the BDNF level in the hippocampus. This suggests that the malfunction of the adipose CX3CL1-mediated mechanism could be involved in the downregulation of the hippocampus BDNF level under obese conditions. Studies have also suggested that the adipose CX3CL1-mediated mechanism appears to be involved in the exercise-induced promotion of BDNF expression in the hippocampus. Its involvement in the fasting-induced BDNF promotion is still unknown. Therefore, aging, obesity, and exercise appear to affect white adipose tissue to regulate the hippocampus BDNF level. While further studies are required to elucidate the precise role of the adipose CX3CL1-mediated regulation of BDNF expression, studies on white adipose tissue may provide new therapeutic targets for preventing age-associated cognitive decline. Full article

Online travel agencies (OTAs) function as e-commerce platforms that facilitate transactions between accommodation providers and consumers, enabling users to efficiently search for, compare, and book travel and lodging services. As the number of OTAs continues to grow, delivering superior service quality has become essential for increasing customer repurchase intentions. Despite its significance, existing research has primarily focused on factors such as website quality, pricing strategies, brand image, and perceived value as determinants of repurchase intention. However, relatively little attention has been paid to the alignment between online information disclosure and customers’ actual offline experiences. To address this gap, the present study introduces the concept of the information disclosure gap and examines its effects on search cost, customer satisfaction, and trust, as well as the subsequent influence of these variables on repurchase intention. A questionnaire-based survey method was conducted with individuals in Taiwan who had prior experience using OTAs, yielding 365 valid responses. This study offers practical insights and recommendations for both OTAs and accommodation providers aimed at reducing the information disclosure gap and strengthening customer repurchase intention. Full article

Accurate estimation of the leaf area index (LAI), a key indicator of canopy development and light interception, is essential for improving productivity in greenhouse tomato cultivation. This study presents a non-destructive LAI estimation method using side-view images captured by a vertical scanning system. The system recorded the full vertical profile of tomato plants grown under two deleafing strategies: modifying leaf height (LH) and altering leaf density (LD). Vegetative and leaf areas were extracted using color-based masking and semantic segmentation with the Segment Anything Model (SAM), a general-purpose deep learning tool. Regression models based on leaf or all vegetative pixel counts showed strong correlations with destructively measured LAI, particularly under LH conditions (R² > 0.85; mean absolute percentage error ≈ 16%). Under LD conditions, accuracy was slightly lower due to occlusion and leaf orientation. Compared with prior 3D-based methods, the proposed 2D approach achieved comparable accuracy while maintaining low cost and a labor-efficient design. However, the system has not been tested in real production, and its generalizability across cultivars, environments, and growth stages remains unverified. This proof-of-concept study highlights the potential of side-view imaging for LAI monitoring and calls for further validation and integration of leaf count estimation. Full article

The major objective was to investigate the protective capabilities of endophytic bacterial strains isolated from a number of medicinal plant species towards Aspergillus spp. secured from the internal tissues of fungi-infected peanuts. Among 32 fungal isolates surveyed for mycotoxin production in various culture media (PDA, RBCA, YES, CA), 10 isolates qualitatively producing AFB₁, besides 10 OTA-producers, were assayed by HPLC for quantitative toxin production. Aspergillus spp. isolate Be 13 produced an extraordinary quantity of 1859.18 μg mL⁻¹ AFB₁, against the lowest toxin level of 280.40 μg mL⁻¹ produced by the fungus isolate IS 4. The estimated amounts of OTA were considerably lower and fell in the range 0.88–6.00 μg mL⁻¹; isolate Sa 1 was superior, while isolate Be 7 seemed inferior. Based on ITS gene sequencing, the highly toxigenic Aspergillus spp. isolates Be 13 and Sa 1 matched the description of A. novoparasiticus and A. ochraceus, respectively, ochraceus, respectively, which are present in GenBank with identity exceeding 99%. According to 16S rRNA gene sequencing, these antagonists labeled Ar6, Ma27 and So34 showed the typical characteristics of Pseudomonas aeruginosa, Bacillus subtilis and Bacillus velezensis, respectively, with similarity percentages of 99–100. The plant growth-promoting activity measurements of the identified endophytes indicated the production of 16.96–80.00 μg/100 mL culture medium of IAA. Phosphate-solubilizing capacity varied among endophytes from 2.50 to 21.38 μg/100 mL. The polysaccharide production pool of bacterial strains ranged between 2.74 and 6.57 mg mL⁻¹. P. aeruginosa Ar6 and B. velezensis successfully produced HCN, but B. subtilis failed. The in vitro mycotoxin biodegradation potential of tested bacterial endophytes indicated the superiority of B. velezensis in degrading both mycotoxins (AFB₁-OTA) with average percentage of 88.7; B. subtilis ranked thereafter (85.6%). The 30-day old peanut (cv. Giza 6) seedlings grown in gnotobiotic system severely injured due to infection with AFB₁/OTA-producing fungi, an effect expressed in significant reductions in shoot and root growth traits. Simultaneous treatment with the endophytic antagonists greatly diminished the harmful impact of the pathogens; B. velezensis was the pioneer, not P. aeruginosa Ar6. In conclusion, these findings proved that several endophytic bacterial species have the potential as alternative tools to chemical fungicides for protecting agricultural commodities against mycotoxin-producing fungi. Full article

Objective: Most studies concentrate on comparisons between the cleavage stage and blastocyst stage of embryos during in vitro stimulation treatment. We aimed, in this study, to compare the pregnancy rates of day 4 or day 5 blastocyst transfers, all derived from fresh, antagonist-regulated in vitro fertilization (IVF) cycles, and to evaluate the factors affecting pregnancy success. Methods: This retrospective cohort study evaluated 3681 fresh embryo transfer cycles conducted at a private IVF center between 2019 and 2021. Patients were divided into two groups based on the day of embryo transfer: day 4 (Group 1) and day 5 (Group 2). Subgroup analyses were performed according to age (≤40 vs. >40 years) and the number of oocytes retrieved (≤4 vs. >4). All patients underwent ovarian stimulation with FSH alone or in combination with hMG, and GnRH antagonist protocols were used for pituitary suppression. Final oocyte maturation was triggered with recombinant hCG, and fertilization was achieved via intracytoplasmic sperm injection (ICSI) for all cases. Embryos were cultured in sequential media and assessed daily until transfer on day 4 or day 5, based on embryo morphology and clinic logistics. Results: Pregnancy was more likely among women under 40 than among women over 40. There were a total of 1217 women who underwent day 4 transfer and 2464 women who underwent day 5 transfer. A total of 660 (54.2%) of the women transferred on day 4 developed pregnancy. Among those transferred on day 5, 1610 (65.3%) developed pregnancy. When compared to the 4th day, a single embryo transfer on the 5th day enhances pregnancy success by 1.8 times, while two embryo transfers raise it by 1.6 times. Furthermore, when the number of oocytes is greater than four and the number of embryos transferred is two, the pregnancy success rate is 2.5 times higher when embryo transfer is performed on the fifth day versus the fourth day. Regardless of age, oocyte count, or number of embryos transferred, 5th-day fresh embryo transfers enhanced pregnancy success by 1.9 times compared to 4th-day transfer. Conclusions: Transfers of fresh embryos on day 5 are superior to those on day 4 and should be favored, especially for people over the age of 40, regardless of the number of embryos transferred, even if that individual has fewer than four oocytes. Full article