Search Results (77)

The time-dependent dielectric breakdown (TDDB) degradation mechanism, governed by the synergistic interaction of multiphysics fields, plays a pivotal role in the performance degradation and eventual failure of semiconductor devices and advanced packaging back-end-of-line (BEOL) structures. This work specifically focuses on the dielectric breakdown mechanism driven by metal ion migration within inter-metal dielectric layers, a primary contributor to TDDB degradation. A SPICE-compatible modeling approach is developed to accurately capture the dynamics of this ion migration-induced degradation. The proposed model is rooted in the fundamental physics of metal ion migration and the evolution of conductive filaments (CFs) within the dielectric layer under operational stress conditions. By precisely characterizing the degradation behavior induced by TDDB, a SPICE-compatible degradation model is developed. This model facilitates accurate predictions of resistance changes across a range of operational conditions and lifetime, encompassing variations in stress voltages, temperatures, and structural parameters. The predictive capability and accuracy of the model are validated by comparing its calculated results with numerical ones, thereby confirming its applicability. Furthermore, building upon the established degradation model, the impact of line-edge roughness (LER) is incorporated through a process variation model based on the power spectral density (PSD) function. This PSD-derived model provides a quantitative characterization of LER-induced fluctuations in critical device dimensions, enabling a more realistic representation of process-related variability. By integrating this stochastic variability model into the degradation framework, the resulting lifetime prediction model effectively captures reliability variations arising from real-world fabrication non-uniformities. Validation against simulation data demonstrates that the inclusion of LER effects significantly improves the accuracy of predicted lifetime curves, yielding closer alignment with observed device behavior under accelerated stress conditions. Full article

This study systematically investigates the evolution of vacancy-type defects and heterogeneous Cu nanoprecipitates in an Fe₆₀Cr₁₂Mn₈Cu₁₅Mo₃V₂ (at%) multi-principal element alloy during thermal processing, utilizing Positron annihilation lifetime spectroscopy (PAS), coincidence Doppler broadening (CDB) spectroscopy, and transmission electron microscopy (TEM). The results show that the alloy exhibited a dual-phase coexistence structure of Body-Centered Cubic (BCC) and Face-Centered Cubic (FCC). The CDB results show that the density of heterogeneous Cu precipitates gradually increases with annealing temperature. Compared to the as-cast alloy, the precipitates annealed at 773 K exhibit a significantly reduced size (approximately 33 nm) with higher density. The PAS results demonstrate that gradual migration and aggregation of monovacancies at 573 K form vacancy clusters, while contraction and dissociation of these clusters dominate at 673 K. Within the temperature range of 773–973 K, the dynamic equilibrium between the aggregation and decomposition of vacancy clusters maintains stable annihilation characteristics with minimal lifetime changes. Full article

The multiscale coupling characteristics of the kinematic interface behavior of mechanical transmission systems are the core factors affecting system accuracy and lifetime. In this paper, we propose an innovative framework to achieve multiscale modeling from surface topographic parameters to system-level dynamics response through four stages: microscopic topographic regulation, mesoscopic wear modeling, macroscopic gap evolution, and system vibration prediction. Through the active design of laser-textured surfaces and gradient coatings, the contact stress distribution can be regulated to keep the wear extension; combined with the multiscale physical model and joint simulation technology, the dynamic feedback mechanism of wear–gap–vibration is revealed. Aiming at the challenges of data scarcity and mechanism complexity, we integrate data enhancement and migration learning techniques to construct a hybrid mechanism–data-driven life prediction model. This paper breaks through the limitations of traditional isolated analysis and provides theoretical support for the design optimization and intelligent operation and maintenance of high-precision transmission systems. Full article

Plasticized polyvinyl chloride (PVC-P) geomembranes (GMBs) are applied as anti-seepage materials in membrane-faced rockfill dams and pumped storage power stations. Assessing their lifetime to ensure durability during operation is crucial. This study conducted accelerated aging tests on three PVC-P GMBs immersed in water, along with axial tensile tests to investigate the degradation of mechanical properties. The degradation model was constructed using the Arrhenius equation, and the time to nominal failure (TNF) was predicted based on this model and failure criterion. The prediction model’s accuracy was verified using test data collected over 180 days at 20 °C. The results demonstrate that the TNF of PVC-P GMBs is influenced by water temperature, plasticizer content, and thickness of GMBs. Elevated temperatures accelerate the loss rate of plasticizers. Specifically, at 20 °C in a water environment, the estimated TNFs of Materials A and B with identical thicknesses were 49.05 and 153.76 years, respectively. This suggests that increasing the initial plasticizer content and enhancing its structural stability can significantly extend the TNF. Furthermore, Material C, which has a composition similar to Material B but with increased thickness, exhibited a predicted TNF of 181.30 years, indicating that greater thickness can effectively reduce the migration rate of plasticizers. The findings provide a theoretical basis for evaluating the TNF of PVC-P GMBs in reservoir bottom and below dead water level applications during operation. Full article

The Multi-Objective Optimization Problem (MOOP) in Wireless Sensor Networks (WSNs) is a challenging issue that requires balancing multiple conflicting objectives, such as maintaining coverage, connectivity, and network lifetime all together. These objectives are important for a functioning WSN safety-critical applications, whether in environmental monitoring, military surveillance, or smart cities. To address these challenges, we propose a novel bio-inspired Bird Flocking Node Scheduling algorithm, which takes inspiration from the natural flocking behavior of birds migrating over long distance to optimize sensor node activity in a distributed and energy-efficient manner. The proposed algorithm integrates the Lyapunov function to maintain connected coverage while optimizing energy efficiency, ensuring service availability and reliability. The effectiveness of the algorithm is evaluated through extensive simulations, namely MATLAB R2018b simulator coupled with a Pareto front, comparing its performance with our previously developed BAT node scheduling algorithm. The results demonstrate significant improvements across key performance metrics, specifically, enhancing network coverage by 8%, improving connectivity by 10%, and extending network lifetime by an impressive 80%. These findings highlight the potential of bio-inspired Bird Flocking optimization techniques in advancing WSN dependability, making them more sustainable and suitable for real-world WSN safety-critical systems. Full article

NAND flash memory has been widely adopted as the primary data storage medium in data centers. However, the inherent characteristic of out-of-place updates in NAND flash necessitates garbage collection (GC) operations on NAND flash-based solid-state drives (SSDs), aimed at reclaiming flash blocks occupied by invalid data. GC processes entail additional read and write operations, which can lead to the blocking of user requests, thereby increasing the tail latency. Moreover, frequent execution of GC operations is prone to induce more pages to be written, further reducing the lifetime of SSDs. In light of these challenges, we introduce an innovative GC scheme, termed SplitGC. This scheme leverages the records of data redundancy gathered during periodic read scrub operations within the SSD. By analyzing these features of data duplication, SplitGC enhances the selection strategy for the victim block. Furthermore, it bifurcates the migration of valid data pages into two phases: non-duplicate pages follow standard relocation procedures, whereas the movement of duplicate pages is scheduled during idle periods of the SSD. The experiment results show that our scheme reduces tail latency induced by GC by 8% to 83% at the 99.99th percentile and significantly decreases the amount of valid page migration by 38% to 67% compared with existing schemes. Full article

The long-term usage of polymer products necessitates addressing the appropriate preservation of their low oxidation state that extends the warranty period. The addition of pertinent stabilization components into the composite formulations (synthesis and natural antioxidants, pristine and doped oxides, clays or couples of them) produces an improvement in the kinetic parameters characterizing the accelerated degradation that occurs during high-energy exposures. The competition between the material ageing and the mitigation of oxidation is controlled by the protection efficiency. In this paper, the main advantages of inorganic structures in comparison to classical organic antioxidants are emphasized. A significant improvement in stability, simultaneously associated with the enhancing of functional characteristics, the lack of migration, low cost and easy accessibility, make the reevaluation of certain fillers as stabilizers appropriate. The correlation between the functional properties and the filler nature in polymer materials may be reconsidered for the assessment of the participation capability of inorganic structures in the inhibition of oxidation by the inactivation of free radicals. The lifetimes of degradation intermediates extended by the activities of inorganic compounds are increased by means of electrical interactions involving the unpaired electrons of molecular fragments. These physical contributions are reflected in chemical stability. An essential feature for the presented inorganic options is a strong impact on the recycling technologies of polymers by radiation processing. Plastic products, including all categories of macromolecular materials, can gain an increased durability through the inorganic alternative of protection. Full article

Photobiomodulation (PBM) therapy, a therapeutic approach utilizing low-level light, has garnered significant attention for its potential to modulate various biological processes. This study aimed at optimizing and investigating the effects of PBM on angiogenesis and mitochondrial metabolic activity. In vitro experiments using human umbilical vein endothelial cells (HUVECs) and vascular smooth muscle cells (VSMCs) were performed to assess PBM’s impacts on cell migration, proliferation, endogenous protoporphyrin IX production, mitochondrial membrane potential, Rhodamine 123 fluorescence lifetime, mitochondrial morphology, and oxygen consumption. Our findings demonstrated that the PBM approach significantly stimulates HUVECs and VSMCs, highlighting the importance of precise light dosimetry for optimal outcomes. Interestingly, our results indicate that in our conditions, the optimal radiometric and spectral parameters are similar for HUVECs and VSMCs for the different endpoints mentioned above. In conclusion, our study strongly suggests that PBM holds promise as a therapeutic intervention for conditions characterized by impaired angiogenesis, such as wound healing, ischemia, and cardiovascular disease. Further research is necessary to fully elucidate the underlying mechanisms and optimize the radiometric and spectral parameters for clinical applications. Full article

Background/Objectives: Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer, with a lifetime risk of 14–20% that is rising every year. Although prognosis for cSCC is generally good, certain high-risk features of cSCC portend increased rates of nodal and distant metastasis, recurrence, and disease-specific mortality. One such high-risk factor is perineural invasion (PNI), which is broadly defined as the invasion of cancer into and around nerves. Compared to other high-risk factors, PNI presence is associated with the highest risk for locoregional and distant metastasis. Still, the mechanisms underlying the pathogenesis of PNI remain poorly understood. Recent studies suggest the migration and invasion of tumors into nerves is a result of complex molecular crosstalk within the tumor-nerve microenvironment, wherein the milieu of signaling molecules simultaneously promote neuronal growth and tumor cell invasion. Methods: Understanding the molecular and cellular mechanisms that promote PNI will lead to future developments of targeted therapies that may improve locoregional control and survival. Results/Conclusions: In our article, we aim to provide a comprehensive review of recent findings about the pathogenesis of PNI, clinical implications of PNI-positive disease in cSCC, available treatment modalities, and potential future therapeutic targets. Full article

Groundwater contamination was studied at several hotspot sites in the Majdanpek copper mining area (Serbia). These sites include a milling facility, a metallurgical wastewater treatment plant, a heavy vehicle service area, and a waste disposal site. In addition to Cu, high concentrations of As and heavy metals (Cd and Pb) were detected in groundwater and soil at the same sampling points. Mining operations and heavy vehicle transport activities have been identified as the main sources of pollution. The migration of metals from soil to groundwater, expressed as a concentration ratio, were the highest for Co and the lowest for Mn. The environmental implications of groundwater pollution were studied using the heavy metal pollution index (HPI), Nemerov pollution index (NPI), hazard index (HI), and incremental lifetime cancer risk (ILCR). HPI and NPI show the high potential of groundwater to have adverse environmental effects. HPI ranges in the following descending order of metals: Cd > Pb > As > Mn > Ni > Cr > Hg > Cu > Zn. NPI exceeds the threshold of 0.7 in 66.7% of the samples. Potential human exposure to the studied groundwater may cause severe health problems in adults, with HI ranging from 0.61 to 5.45 and ILCR from 1.72 × 10⁻⁴ to 1.27 × 10⁻³. Children were more susceptible to non-carcinogenic risk than adults, with HI ranging from 0.95 to 8.27. However, the results indicated that children were less prone to carcinogenic risks, with ILCR ranging from 5.35 × 10⁻⁵ to 3.98 × 10⁻⁴. Arsenic is the most contributing element to both risks. This research imposes the need for enhanced groundwater monitoring at hotspots in the mining area and the adoption of remediation plans and measures. Full article

In this study, the photoluminescence (PL) behavior of two aluminosilicate glass series containing alkali-niobates ranging from 0.4 to 20 mol% was investigated. The glasses exhibit an intense visible emission centered at ~18,400 cm⁻¹ for the peralkaline series and at higher energies (~19,300 cm⁻¹) for the metaluminous glasses. However, the photoluminescence emission intensity varies significantly with the niobate content and the bulk chemistry. PL and fluorescence lifetime measurements indicate that the broad emission bands result from the overlap of different niobate populations, whose distribution changes with niobate content. The distinct PL behavior in the two glass series was related to the structural evolution of the niobate units upon niobium addition. An enhancement of the visible emission was observed for a higher fraction of distorted [NbO₆] units. Eu-doping was carried out as a structural probe of the glass network, and also to determine if these glasses could be used as potential rare earth element (REE) activators. The crystal field strength around Eu ions is strongly dependent on the bulk chemistry and the niobate content. Furthermore, the peralkaline series showed energy transfer from the host [NbO₆] to Eu³⁺, confirming the feasibility of exploring niobate glasses and glass-ceramics as lanthanide ion-activated luminescent materials. In addition, glass-ceramics (GCs) containing alkali-niobate phases with a perovskite-like structure were developed and studied to verify the optical performance of these materials. It was verified that the bulk chemistry influences crystallization behavior, and also the photoluminescence response. The transparent GC from the metaluminous series exhibits a quenching of the Eu³⁺ emission, whereas an enhanced emission intensity is observed for the peralkaline GC. The latter shows a strong excitation-dependent PL emission, suggesting energy transfer and migration of electronic excitation from one Eu population to another. Additionally, Eu³⁺ emissions arising from the $D_1_5^{}$ and $D_2_5^{}$ excited states were observed, highlighting the low phonon energy achievable in niobo-aluminosilicate hosts. Full article

This investigation explores the structural and electronic properties of low-temperature-grown (InAs)₄(GaAs)₃/Be-doped InAlAs and InGaAs/Be-doped InAlAs multiple quantum wells (MQWs), utilizing migration-enhanced epitaxy (MEE) and conventional molecular beam epitaxy (MBE) growth mode. Through comprehensive characterization methods including transmission electron microscopy (TEM), Raman spectroscopy, atomic force microscopy (AFM), pump–probe transient reflectivity, and Hall effect measurements, the study reveals significant distinctions between the two types of MQWs. The (InAs)₄(GaAs)₃/Be-doped InAlAs MQWs grown via the MEE mode exhibit enhanced periodicity and interface quality over the InGaAs/Be-InAlAs MQWs grown through the conventional molecule beam epitaxy (MBE) mode, as evidenced by TEM. The AFM results indicate lower surface roughness for the (InAs)₄(GaAs)₃/Be-doped InAlAs MQWs by using the MEE mode. Raman spectroscopy reveals weaker disorder-activated modes in the (InAs)₄(GaAs)₃/Be-doped InAlAs MQWs by using the MEE mode. This originates from utilizing the (InAs)₄(GaAs)₃ short period superlattices rather than InGaAs, which suppresses the arbitrary distribution of Ga and In atoms during the InGaAs growth. Furthermore, pump–probe transient reflectivity measurements show shorter carrier lifetimes in the (InAs)₄(GaAs)₃/Be-doped InAlAs MQWs, attributed to a higher density of antisite defects. It is noteworthy that room temperature Hall measurements imply that the mobility of (InAs)₄(GaAs)₃/Be-doped InAlAs MQWs grown at a low temperature of 250 °C via the MEE mode is superior to that of InGaAs/Be-doped InAlAs MQWs grown in the conventional MBE growth mode, reaching 2230 cm²/V.s. The reason for the higher mobility of (InAs)₄(GaAs)₃/Be-doped InAlAs MQWs is that this short-period superlattice structure can effectively suppress alloy scattering caused by the arbitrary distribution of In and Ga atoms during the growth process of the InGaAs ternary alloy. These results exhibit the promise of the MEE growth approach for growing high-performance MQWs for advanced optoelectronic applications, notably for high-speed optoelectronic devices like THz photoconductive antennas. Full article

We are exposed to a mixture of environmental man-made and natural xenobiotics. We experience a wide spectrum of environmental exposure in our lifetime, including the effects of xenobiotics on gametogenesis and gametes that undergo fertilization as the starting point of individual development and, moreover, in utero exposure, which can itself cause the first somatic or germline mutation necessary for breast cancer (BC) initiation. Most xenobiotics are metabolized or/and bioaccumulate and biomagnify in our tissues and cells, including breast tissues, so the xenobiotic metabolism plays an important role in BC initiation and progression. Many considerations necessitate a more valuable explanation regarding the molecular mechanisms of action of xenobiotics which act as genotoxic and epigenetic carcinogens. Thus, exposomics and the exposome concept are based on the diversity and range of exposures to physical factors, synthetic chemicals, dietary components, and psychosocial stressors, as well as their associated biologic processes and molecular pathways. Existing evidence for BC risk (BCR) suggests that food-borne chemical carcinogens, air pollution, ionizing radiation, and socioeconomic status are closely related to breast carcinogenesis. The aim of this review was to depict the dynamics and kinetics of several xenobiotics involved in BC development, emphasizing the role of new omics fields related to BC exposomics, such as environmental toxicogenomics, epigenomics and interactomics, metagenomics, nutrigenomics, nutriproteomics, and nutrimiRomics. We are mainly focused on food and nutrition, as well as endocrine-disrupting chemicals (EDCs), involved in BC development. Overall, cell and tissue accumulation and xenobiotic metabolism or biotransformation can lead to modifications in breast tissue composition and breast cell morphology, DNA damage and genomic instability, epimutations, RNA-mediated and extracellular vesicle effects, aberrant blood methylation, stimulation of epithelial–mesenchymal transition (EMT), disruption of cell–cell junctions, reorganization of the actin cytoskeleton, metabolic reprogramming, and overexpression of mesenchymal genes. Moreover, the metabolism of xenobiotics into BC cells impacts almost all known carcinogenic pathways. Conversely, in our food, there are many bioactive compounds with anti-cancer potential, exerting pro-apoptotic roles, inhibiting cell cycle progression and proliferation, migration, invasion, DNA damage, and cell stress conditions. We can conclude that exposomics has a high potential to demonstrate how environmental exposure to xenobiotics acts as a double-edged sword, promoting or suppressing tumorigenesis in BC. Full article

Tunneling nanotubes (TNTs) are fine, nanometer-sized membrane connections between distant cells that provide an efficient communication tool for cellular organization. TNTs are thought to play a critical role in cellular behavior, particularly in cancer cells. The treatment of aggressive cancers such as glioblastoma remains challenging due to their high potential for developing therapy resistance, high infiltration rates, uncontrolled cell growth, and other aggressive features. A better understanding of the cellular organization via cellular communication through TNTs could help to find new therapeutic approaches. In this study, we investigate the properties of TNTs in two glioblastoma cell lines, U87 MG and LN229, including measurements of their diameter by high-resolution live-cell stimulated emission depletion (STED) microscopy and an analysis of their length, morphology, lifetime, and formation by live-cell confocal microscopy. In addition, we discuss how these fine compounds can ideally be studied microscopically. In particular, we show which membrane-labeling method is suitable for studying TNTs in glioblastoma cells and demonstrate that live-cell studies should be preferred to explore the role of TNTs in cellular behavior. Our observations on TNT formation in glioblastoma cells suggest that TNTs could be involved in cell migration and serve as guidance. Full article

The growth of InGaAs quantum wells (QWs) epitaxially on InP substrates is of great interest due to their wide application in optoelectronic devices. However, conventional molecular beam epitaxy requires substrate temperatures between 400 and 500 °C, which can lead to disorder scattering, dopant diffusion, and interface roughening, adversely affecting device performance. Lower growth temperatures enable the fabrication of high-speed optoelectronic devices by increasing arsenic antisite defects and reducing carrier lifetimes. This work investigates the low-temperature epitaxial growth of InAs/GaAs short-period superlattices as an ordered replacement for InGaAs quantum wells, using migration-enhanced epitaxy (MEE) with low growth temperatures down to 200–250 °C. The InAs/GaAs multi-quantum wells with InAlAs barriers using MEE grown at 230 °C show good single crystals with sharp interfaces, without mismatch dislocations found. The Raman results reveal that the MEE mode enables the growth of (InAs)₄(GaAs)₃/InAlAs QWs with excellent periodicity, effectively reducing alloy scattering. The room temperature (RT) photoluminescence (PL) measurement shows the strong PL responses with narrow peaks, revealing the good quality of the MEE-grown QWs. The RT electron mobility of the sample grown in low-temperature MEE mode is as high as 2100 cm²/V∗s. In addition, the photoexcited band-edge carrier lifetime was about 3.3 ps at RT. The high-quality superlattices obtained confirm MEE’s effectiveness for enabling advanced III-V device structures at reduced temperatures. This promises improved performance for applications in areas such as high-speed transistors, terahertz imaging, and optical communications. Full article