Search Results (44)

Solar tracking can increase photovoltaic (PV) energy yield, but its contribution to sustainable electricity depends on more than geometric gain. This structured narrative review evaluates flat-plate and low-concentration PV trackers using an integrated three-layer taxonomy covering mechanical architecture, actuation and drivetrain, and control strategy. Tracker classes are compared in terms of annual energy gain, life-cycle cost, parasitic consumption, land-use efficiency, structural resilience, reliability, maintainability, and deployment maturity. Utility-scale horizontal single-axis trackers using astronomical control, backtracking, supervisory monitoring, and weather-dependent stow provide the most mature balance of energy yield, cost, and operational robustness. Dual-axis systems can offer higher output under high-direct-normal-irradiance conditions but impose greater structural and O&M burdens, while passive fluid-based and shape-memory-alloy concepts remain mainly experimental. The review also examines bifacial and terrain-aware tracking, agrivoltaic dual land use, extreme-weather resilience, tracker-specific availability, artificial intelligence, digital twins, predictive maintenance, and end-of-life considerations. A plant-level decision framework and reporting checklist are proposed to support transparent, project-specific choices that maximize lifetime renewable-energy value while limiting material use, land-use conflict, operational risk, and avoidable life-cycle impacts. Full article

Microalgae biophotovoltaic (BPV) systems convert solar energy into electricity through photosynthetic electron transfer (PET) and have emerged as a promising solar-integrated bioenergy technology. However, high-density tubular arrays suffer from the “canyon effect” at low solar angles and from photoinhibition under peak irradiance (>450 W/m²), where non-photochemical quenching (NPQ) and reactive oxygen species (ROS) dissipate bioelectric potential as heat. To address this, a hysteresis-based dual-mode PID controller with hysteresis switching is proposed within an optical–mechanical–biological co-optimization framework, integrating array self-shading, nonlinear microalgal photoresponse, and tracking parasitic losses. In low-light mode, the system actively tracks the sun to minimize shading; in peak-light mode, it defocuses the incident angle to limit irradiance near the saturation threshold, mitigating the risk of photoinhibition. Structural control boundaries, including tube spacing and connecting rod length, are determined numerically. Under the nominal clear-sky design day, the defocusing mode reduces the daily exposure of the culture to irradiance above the saturation threshold (450 W/m²) from 5.28 h to 3.08 h. Numerical simulations indicate a daily net energy yield improvement of +14.9% over continuous dual-axis tracking and +6.3% over the latitude-based fixed-tilt baseline under idealized clear-sky design-day conditions. These values are simulation-derived estimates; experimental validation with a physical prototype is required before the framework can be interpreted as a validated system-level performance gain. Full article

Discrete-time sliding mode controllers that utilize saturation-based reaching laws require a gain that ensures contraction within the boundary layer in the presence of multiplicative gain uncertainty. The conventional fixed-gain approach does not maintain this property at moderate uncertainty levels. This work introduces a family of admissible reaching gains and identifies a unique optimal gain that guarantees a specified worst-case contraction. The proposed method offers a closed-form solution to the worst-case contraction problem over the gain-uncertainty interval and determines the optimal contraction factor for the saturation-based reaching law for any finite uncertainty ratio. The optimal gain is integrated into a discrete-time integral sliding-mode framework, thereby eliminating the reaching phase. Furthermore, a past-step disturbance estimator with a confidence factor is introduced to prevent error amplification, which reduces the quasi-sliding band from first to second order in the sampling period when the realized gain approximates its nominal value. The effectiveness of the proposed approach is validated through its application to a photovoltaic battery-charging system with a DC–DC boost converter, achieving robust inductor-current regulation across three battery banks under varying irradiance conditions in a switching-level model with parasitic elements. Full article

Single-Event Burnout (SEB) is one of the most critical failure mechanisms in silicon power MOSFETs operating in radiation environments, particularly under heavy-ion irradiation, and often limits device operation through excessive voltage derating. In this work, SEB robustness of a silicon VDMOS power device is investigated using detailed electro-thermal transient simulations. The study evaluates two complementary device-level modifications: the introduction of a buffer layer between the epitaxial layer and the substrate, which has been reported in the past, and a new approach considering the incorporation of a novel highly doped boron BOX implant within the P-body region. Heavy-ion impacts are simulated using a physically based model implemented in SENTAURUS TCAD, accounting for ion energy deposition, impact position, and thermal effects. The results show that the buffer layer increases the second breakdown voltage and can suppress high-current operating points, while the BOX implant raises the parasitic BJT activation threshold by reducing the P-body resistance. When combined, both modifications lead to a significant reduction in the peak temperature reached during after-impact transients, without introducing measurable degradation of static electrical characteristics. These results demonstrate that combining buffer layer engineering with localized P-body resistance reduction is an effective strategy to improve SEB robustness in silicon VDMOS power devices without relying on excessive derating. Full article

Cell membranes and the cytoskeleton play crucial roles in the regulation of cellular responses by mediating mechanical forces and physical stimuli from the microenvironment through their viscoelastic properties. Investigating these properties provides valuable insights into disease mechanisms and therapeutic strategies. Gold nanorods (GNRs), especially under irradiation, exhibit lethal effects against Leishmania parasites through plasmonic photothermal conversion. In this study, we focus on evaluating the effects of non-irradiated GNRs on macrophage properties to better understand their intrinsic interactions with cells and support the development of future phototherapy applications. Here, defocusing microscopy (DM), a quantitative phase microscopy technique, was used to analyze membrane fluctuations in macrophages ($M\varnothing s$) exposed to GNRs (average length of $43\pm 8 \mathrm{n}\mathrm{m}$ and diameter of $20\pm 4 \mathrm{n}\mathrm{m}$) and infected with Leishmania amazonensis. By quantifying membrane–cytoskeleton fluctuation from defocused images, we extracted viscoelastic parameters, including bending modulus ($k_c$) and viscosity ($\eta$), to characterize membrane behavior in detail. Our results show that infection increases both $k_c$ and $\eta$, while treatment at IC₅₀ reduces infection and selectively increases $k_c$ without affecting $\eta$. In healthy macrophages, exposure to GNRs resulted in a reduction in both parameters, indicative of increased membrane fluidity and cytoskeletal rearrangement. These findings provide new insights into the biomechanical effects of GNRs on macrophages and may enlighten the design of future phototherapeutic approaches. Full article

The age-dependent reproductive behavior of parasitoid females under mass-rearing conditions may influence the quality of the biocontrol agents produced. Therefore, this study assessed the egg allocation behavior of Diachasmimorpha longicaudata (Ashmead) females at different ages under mass-rearing conditions. This parasitoid native to Southeast Asia is mass-reared on irradiated Anastrepha ludens (Loew) larvae at the Moscafrut Program facility in Mexico and is released in crop areas to suppress fruit fly pest species. Parasitoid females aged 5–10 days were used to assess quality control parameters, such as parasitized host mortality, parasitoid emergence, offspring sex ratio, and superparasitism. Anastrepha ludens puparia were checked and dissected 72 h after being exposed to female parasitoids to determine the number of scars on the puparium of first-instar parasitoids, respectively. Parasitized puparia were kept under lab conditions to assess adult emergence and offspring sex ratio. Host mortality, superparasitism, and parasitoid offspring sex ratio were affected by female age. The highest host mortality and superparasitism were caused by 5–7-day-old females, which also produced a significantly higher female-to-male offspring ratio with improved fitness-related parameters. The use of cages with females of these ages may improve the quality parameters of parasitoids and result in higher female-to-male offspring sex ratios. Furthermore, production costs could be lowered by reducing the quantity of hosts and rearing commodities. These findings are a useful contribution to improving the current method used for the mass rearing of D. longicaudata at the Moscafrut Program facility. Full article

Trichomonas vaginalis, the protozoan responsible for trichomoniasis, encounters fluctuating levels of metal cations in the male urogenital tract, notably zinc (Zn²⁺) and cadmium (Cd²⁺), which may induce genotoxic stress. While zinc is a key physiological component of the male reproductive tract, both Zn²⁺ and Cd²⁺ can become genotoxic at elevated concentrations. However, their effect on DNA repair mechanisms in T. vaginalis remains poorly understood. This study characterizes, for the first time, the expression and modulation of the recombinase TvRAD51, a homologous recombination (HR) key enzyme, in response to UV irradiation and sublethal concentrations of Zn²⁺ (1.6 mM) and Cd²⁺ (0.1 mM). In silico analyses confirmed the presence and conserved structure of the tvrad51 gene and its interaction with HR-related proteins, such as TvBLM and TvBRCA2. Quantitative RT-PCR, Western blot, and immunofluorescence assays revealed that TvRAD51 is upregulated at both transcript and protein levels following UV- and cation-induced DNA damage, with distinct temporal expression patterns for Zn²⁺ and Cd²⁺ exposure. Notably, TvRAD51 showed nuclear localization at early time points post-exposure, suggesting active participation in DNA repair processes. These findings demonstrate that TvRAD51 is a central component of the genotoxic stress response in T. vaginalis, potentially contributing to parasite survival and adaptation in hostile environments through homologous recombination repair pathways. Full article

Trichopria drosophilae is a globally distributed pupal parasitoid that targets various species within the Drosophilidae family, including the invasive Drosophila suzukii. The mass rearing of T. drosophilae is a crucial step in ensuring their successful application for field D. suzukii control. The pupae of Drosophila melanogaster are currently used as a host for the mass rearing of T. drosophilae. After irradiation, the immune system function of Drosophila pupae was weakened, leading to an increase in the parasitism efficiency of the T. drosophilae. Our results showed that irradiated pupae had a significant impact on the parasitism rate, offspring eclosion rate, offspring number, and female body size of F1 T. drosophilae, all of which were significantly lower than those in the normal group. However, there was no significant difference in the parasitism rate, body size, offspring eclosion rate, offspring number, or offspring sex ratio between F2 T. drosophilae emerging from treated or untreated Drosophila pupae. Compared with F2, F1 had a significantly higher net reproductive rate (R₀), mean generation time (T), and doubling time (DT), while the intrinsic rate of increase (r) was significantly lower. Using irradiated D. melanogaster pupae provides an efficient method for the mass rearing of T. drosophilae and offers valuable insights into its potential effectiveness in field D. suzukii control. Full article

Ivermectin (IVM) is a pharmaceutical antiparasitic agent with a broad range of medicinal properties that are comparable in impact to those of penicillin and aspirin. The molecule’s structural composition includes functional groups that indicate the potential for photoreactivity. However, there is a paucity of information regarding its photostability, particularly in tropical regions where parasitic diseases and intense solar radiation intersect. It would be beneficial to investigate the chemical transformation of this compound in a variety of natural aqueous environments under different irradiation sources. This knowledge gap motivated this study. Therefore, the chemical alterations of IVM were investigated in various natural aqueous media when exposed to solar radiation (UVA-Vis). In particular, an evaluation of its photostability was conducted at wavelengths of 350 and 254.5 nm. It is noteworthy that photodegradation occurred primarily at 350 nm. Additionally, IVM demonstrated photohemolytic effects on human erythrocytes, indicating phototoxicity. This suggests the presence of photoinduced mechanisms by this drug for the generation of free radicals, including singlet oxygen (¹O₂, type II mechanism), superoxide anion, and hydroxyl radical (^.O₂ and ^.OH, type I mechanism). The latter would also entail the interaction of the IVM molecule with the membrane of human red blood cells, which would signify a considerable biological impact. Furthermore, through computational calculations, potential photoproducts formed during IVM irradiation were deduced, simulating experimental conditions. Our findings contribute to an enhanced comprehension of IVM’s behavior under solar exposure, particularly in tropical contexts. Additional research is imperative to address its emerging biological activity status and potential implications for biomedical applications. Full article

Amid the shift away from fossil fuels, third-generation perovskite solar cells (PSCs) have become pivotal due to their high efficiency and low production costs. This review concentrates on semi-transparent perovskite solar cells (ST-PSCs), highlighting their power conversion efficiency (PCE) and average visible transmittance (AVT). We address strategies to optimize ST-PSC performance, tackling inherent challenges, such as optical losses from reflection, parasitic absorption, and thermalization loss, which impact the operational efficiency under variable environmental conditions. ST-PSCs are distinguished by their lightweight, flexible, and translucent properties, allowing for diverse applications in urban building integration, agricultural greenhouses, and wearable technology. These cells integrate seamlessly into various settings, enhancing energy harnessing without compromising on aesthetic or structural elements. However, the scalability of ST-PSCs involves challenges related to stability and efficiency in large-scale deployments. The tropical urban landscape of Singapore provides a unique case study for ST-PSC application, blending architectural aesthetics with high solar irradiance to optimize energy efficiency. While the potential for ST-PSCs to contribute to sustainable urban development is immense, significant technological hurdles must be overcome to realize their full potential. Continued advancements in material science and engineering are essential to address these challenges, ensuring the scalability and long-term deployment of ST-PSCs in global energy solutions. Full article

The carnivorous fungus Drechslerella dactyloides can form constricting rings through hyphal specialization to capture nematodes. The formation of constricting rings is a prerequisite for capturing nematodes and a characteristic of entering the carnivorous stage. Currently, there is limited research on the molecular mechanism of constricting ring formation. In this study, two D. dactyloides mutants unable to form constricting rings were obtained through UV irradiation mutagenesis, and their growth and development phenotypes were compared with the wild-type strain. Transcriptome comparisons revealed differences between the mutants and the wild-type strain in metabolic pathways related to cell wall structure, peroxisomes, lipid metabolism, and MAPK signal transduction, which we validated through qPCR. We further deleted one differentially expressed gene, DdSTE2, of the MAPK pathway and confirmed its role in conidiogenesis and trap formation in D. dactyloides. Together, our results indicate that the remodeling of cell wall structure, peroxisomes, lipid metabolism, and MAPK signal transduction pathways are involved in the formation and maturation of D. dactyloides constricting rings. We discuss the implications of these results for utilizing these fungi to control animal and plant parasitic nematodes. Full article

Sentinel eggs used to monitor field parasitism of stink bug pests (Hemiptera: Pentatomidae) can only be deployed for a few days to avoid releasing the pest in the monitored area. Using sterile eggs removes the risk of accidental pest introduction and extends deployment time. Freezing the eggs before deployment is one common method of sterilizing sentinel eggs. However, some egg parasitoid species have low or no parasitism on frozen eggs. In this study, X-ray irradiation was used to sterilize Bagrada hilaris sentinel eggs intended for monitoring parasitism by Gryon aetherium (Hymenoptera: Scelionidae), the most promising biological control candidate. In this case, freezing sentinel eggs is not recommended because G. aetherium has low levels of parasitism on frozen eggs. Doses as low as 10 Gy induced 100% sterility. Irradiated eggs successfully sustained the development of G. aetherium and Ooencyrtus californicus (Hymenoptera: Encyrtidae), another egg parasitoid attacking B. hilaris, and parasitism levels were comparable to that of fresh eggs up to seven days old. In addition, G. aetherium showed no preference for fresh non-irradiated eggs over seven-day-old irradiated eggs. Our results indicate that X-ray irradiation is a suitable alternative to produce safe and reliable sentinel eggs to monitor the egg parasitism of B. hilaris and possibly other species. Full article

The incessant threat posed by the Varroa destructor mite to bee colonies has spurred extensive research into control strategies. One of these strategies involves ultraviolet radiation, aiming to harness the damaging effects that this type of radiation induces in arthropods. This study focuses on investigating the potential influence of near ultraviolet (UVA) radiation on the surface damage incurred by Varroa destructor. To address this inquiry, multiple specimens were continuously irradiated with UVA while digital holograms were recorded. To assess surface damage, these holographic records were processed and analyzed. It was found that exposure to radiation induces subtle swelling, around a few tenths of micrometers, which is more pronounced around the anal shield and genital shield of the mite. These alterations could impact the health and viability of this parasitic mite. This is the first time that the measurement and quantification of this superficial damage is reported, contributing to the understanding of the impact of UVA irradiation on the external structure of the mite. Full article

In present times, with increasing emphasis on circular economies, municipal wastewater treatment plants (WWTPs) are considered resource recovery facilities. The targeted resources are water, biogas, and sludge, organic residuals containing nutrients and elements needed by plants (nitrogen and phosphorus). Sludge is a byproduct that constitutes the largest volume of all other byproducts obtained in wastewater treatment plants. Its processing and disposal are challenging for environmental engineers because of its complexity. Thus, quick development and implementation in industrial practice of sludge valorization and utilization technologies is required, where high nutrient content must be taken into account. Also, the occurrence of a variety of pathogens in sewage sludge is a matter of concern, even in the case of developed countries. The use of untreated sludge or wastewater in agricultural activities poses a serious risk of bacterial and parasitic infection in human beings. To overcome such issues, the application of ionizing radiation processing, especially electron beam (EB), can be considered a promising method. Its effectiveness in pathogen removal has been proven by researchers. Water radiolysis products created during irradiation of water are highly reactive and cause some effects such as DNA damage, ${}_{ }{}^{•}OH$ radical production, etc. Additionally, ionizing radiation technologies in sewage sludge treatment enhance the efficiency of the methane fermentation process. Depending on specific needs, different types of ionizing radiation sources can be discussed. Based on the review information and our research results, the basic engineering parameters of hybrid installation have been presented as the conclusion of the report. In this technical solution, a notably effective additional step would be the use of EB irradiation, combined with conventional wastewater treatment, to achieve efficient removal of pollutants. Full article

Antimicrobial photodynamic inactivation (aPDI) is a method that specifically kills target cells by combining a photosensitizer and irradiation with light at the appropriate wavelength. The natural amino acid, 5-aminolevulinic acid (5-ALA), is the precursor of endogenous porphyrins in the heme biosynthesis pathway. This review summarizes the recent progress in understanding the biosynthetic pathways and regulatory mechanisms of 5-ALA synthesis in biological hosts. The effectiveness of 5-ALA-aPDI in destroying various groups of pathogens (viruses, fungi, yeasts, parasites) was presented, but greater attention was focused on the antibacterial activity of this technique. Finally, the clinical applications of 5-ALA in therapies using 5-ALA and visible light (treatment of ulcers and disinfection of dental canals) were described. Full article