Search Results (34,611)

Data sovereignty has emerged as a critical concern for enterprises, cloud service providers (hyperscalers), end-users, and policymakers at both national and international levels. In response, cloud-based distributed computing models have been proposed as frameworks to enforce data sovereignty requirements. This study aims to evaluate and enhance data sovereignty practices within public cloud environments. Through a comprehensive literature review, we analyze existing reference architectures and solutions that address data sovereignty, identifying the technological and economic constraints they impose, such as increased computational costs associated with specific frameworks and cryptographic measures. To address these challenges, we propose an abstract data sovereignty model designed to aid system designers and architects in developing compliant cloud-based systems. Additionally, we conduct computational experiments assessing the performance of the IDS connector, a key data sovereignty tool, deployed on the Google Cloud Platform and Microsoft Azure. Results reveal that while the geographic location of the software significantly impacts performance, the choice of cloud platform minimally influences the IDS connector’s efficiency. These findings offer insights into optimizing data sovereignty strategies for cloud solutions, with implications for future system design and policy development. Full article

In order to consider the impact of multiple uncertainties on the interaction between the distribution network operator (DNO) and photovoltaic powered charging stations (PVCSs), this paper proposes a regulation strategy for a distribution network with a PVCS based on bi-level stochastic optimization. First, the interaction framework between the DNO and PVCS is established to address the energy management and trading problems of different subjects in the system. Second, considering the uncertainties in the electricity price and PV output, a bi-level stochastic model is constructed with the DNO and PVCS targeting their respective interests. Furthermore, the conditional value-at-risk (CVaR) is introduced to measure the relationship between the DNO’s operational strategy and the uncertain risks. Next, the Karush–Kuhn–Tucker (KKT) conditions and duality theorem are utilized to tackle the challenging bi-level problem, resulting in a mixed-integer second-order cone programming (MISCOP) model. Finally, the effectiveness of the proposed regulation strategy is validated on the modified IEEE 33-bus system. Full article

A discrete time modeling method is employed in this paper to analyze and evaluate the reliability of a discrete time K/N: G repairable retrial system with Bernoulli shocks and two-stage repair. Lifetime and shocks are two factors that lead to component failure, and both of them can lead to the simultaneous failure of multiple components. When the repairman is busy, the newly failed component enters retrial orbit and retries in accordance with the first-in-first-out (FIFO) rule to obtain the repair. The repairman provides two-stage repair for failed components, all of which require basic repair and some of which require optional repair. The discrete PH distribution controls the repair times for two stages. Based on discrete time stochastic model properties, priority rules are defined when multiple events occur simultaneously. The state transition probability matrix and state set analysis are used to evaluate the system performance indexes. Numerical experiments are used to illustrate the main performance indexes of the developed discrete time model, and the impact of each parameter variation on the system indexes is examined. Full article

The combined pressures of climate change and human activities have exacerbated ecological risks in fragile and sensitive areas. Assessing the ecological restoration status of key nature reserves and developing a new conservation and development framework are fundamental for achieving ecological civilization and enhancing sustainability. As an ecological security barrier in the northwestern alpine region, Qilian Mountain National Park (QMNP), is of great significance for maintaining the sustainable ecological environment of western China. By measuring changes in ecological land use and monitoring key vegetation indicator trends in QMNP, we constructed the Regional Ecological Resilience Indicator (RERI) and proposed a new restoration and restoration framework. The results show that: (1) the ecological land restoration in QMNP was remarkable, with a total of 721.76 km² of non-ecological land converted to ecological land, representing a 1.44% increase. Forest restoration covered 110 km², primarily made up of previously unused land from 2000 to 2020. (2) The average NDVI value increased by 0.025. Regions showing productivity growth (NPP) accounted for 51.82% of the total area from 2000 to 2020. The four typical eco-migration zones reduced the building profile area by 47.72% between 2015 and 2019. The distribution of high Composite Vegetation Index (CFI) values overlapped with concentrated forest restoration areas, revealing two main restoration models: forest conservation and population relocation. (3) RERI calculations divided the park into three ecological zones, Priority Conservation Area (PCA), Optimization and Enhancement Area (OEA), and Concerted Development Area (CDA), leading to the proposal of an ecological restoration and development framework for QMNP, characterized by “three zones, two horizontal axes, and one vertical axis”. Our findings contribute to strengthening the ecological security barrier in northwestern China; they offer new insights for the long-term, stable improvement of the ecological environment in QMNP and in other critical protected area systems globally. Full article

The monkeypox outbreak has grown beyond the regions in which it was considered endemic. It has spread from central and west Africa to non-endemic regions like Europe, America, and other parts of the world. It has recently been classified as a public health emergency of international concern. This study evaluated the challenges faced globally and equitable access to monkeypox vaccines. Global competition has been observed in the race to obtain vaccines, with low- and middle-income countries being disadvantaged. Great inequity exists in the distribution of vaccines globally through advance purchase agreements, vaccine stockpiling, vaccine nationalism, the inequitable distribution of existing resources, and insufficient surveillance and reporting mechanisms. To address some of these challenges, there is a need for strengthening the global vaccine manufacturing capacity, targeting countries with elevated risk profiles and limited resources, strengthening surveillance systems, and addressing vaccine hesitancy. Full article

With the continuous advancement of urbanization, rural areas are facing increasingly severe environmental pollution, excessive energy consumption, and high carbonization resulting from both daily living and production activities. This study, which is aligned with the low-carbon objectives of “carbon sequestration increase and emissions reduction”, explores the optimization strategies for ecological benefits through the combined application of rooftop photovoltaics and rooftop greening in rural residences. Three design approaches are proposed for integrating rooftop photovoltaics with green roofing: singular arrangement, distributed arrangement, and combined arrangement. Using PVsyst (7.4.7) software, this study simulates the effects of roof inclination, system output, and installation formats on the performance of photovoltaic systems, providing a comprehensive analysis of carbon reduction benefits in ecological rooftop construction. A rural area in East China was selected as a sample for adaptive exploration of ecological roof applications. The results of our research indicate that the optimal tilt angle for rooftop photovoltaic (PV) installations in the sample rural area is 17°. Based on simulations combining the region’s annual solar path and the solar parameters on the winter solstice, the minimum spacing for PV arrays is calculated to be 1.925 m. The carbon reduction benefits of the three arrangement methods are ranked, from highest to lowest, as follows: combined arrangement > singular arrangement > distributed arrangement . The integrated design of rooftop PV systems and green roofing not only meets the energy demands of buildings but also significantly reduces their carbon footprint, achieving the dual objectives of energy conservation and sustainable development. Therefore, the combined application of rooftop PV systems and green roofing in rural spaces can provide data support and strategic guidance for advancing green transformation and ecological civilization in East China, offering significant practical value for promoting low-carbon rural development. Full article

Background: Internal ocular diseases, such as macular edema, uveitis, and diabetic macular edema require precise delivery of therapeutic agents to specific regions within the eye. However, the eye’s complex anatomical structure and physiological barriers present significant challenges to drug penetration and distribution. Traditional eye drops suffer from low bioavailability primarily due to rapid clearance mechanisms. Methods: The novel ocular drug delivery system developed in this study utilizes poly(lactic-co-glycolic acid) (PLGA) nanoparticles modified with cell-penetrating peptides (CPPs). In vitro drug release studies were conducted to evaluate the sustained-release properties of the nanoparticles. Ex vivo experiments using MDCK cells assessed corneal permeability and uptake efficiency. Additionally, in vivo studies were performed in rabbit eyes to determine the nanoparticles’ resistance to elimination by tears and their retention time in the aqueous humor. Results: In vitro drug release studies demonstrated superior sustained-release properties of the nanoparticles. Ex vivo experiments revealed enhanced corneal permeability and increased uptake efficiency by MDCK cells. In vivo studies in rabbit eyes confirmed the nanoparticles’ resistance to elimination by lacrimal fluid and their ability to extend retention time in the aqueous humor. CPP modification significantly improved ocular retention, corneal penetration, and cellular endocytosis efficiency. Conclusions: The CPP-modified PLGA nanoparticles provide an effective and innovative solution for ocular drug delivery, offering improved bioavailability, prolonged retention, and enhanced drug penetration, thereby overcoming the challenges of traditional intraocular drug administration methods. Full article

Background: The “streamline flow” of the portal vein (PV) is a controversial yet well-known theory presented almost 125 years ago. It states that blood from the superior mesenteric vein (SMV) goes preferentially to the right liver lobe, while splenic and inferior mesenteric veins divert blood predominantly to the left lobe, affecting this way the metastatic distribution of colorectal cancer (CRC). The aim of this systematic review is to assess its validity by examining and combining all the relevant literature with a critical eye. Materials and methods: This study constitutes a systematic review of the literature and adheres to all PRISMA system criteria. Three search engines (PubMed, Google Scholar, and the Cochrane Library) were used, and 11 out of 435 studies between 1984 and 2024 were finally included in this meta-analysis. All statistical analysis was conducted using RevMan Web, Version: 7.12.0, and Jamovi v 2.3.260 software. Results: The meta-analysis revealed that regardless of the primary location of the tumor, the metastases preferentially migrate to the right lobe due to various possible reasons. The prevalence of metastases from right colon cancer to the right liver lobe was 75%, while the prevalence of left colon cancer metastases to the right lobe was 68%. This difference was not found statistically significant. Conclusions: The theory has been proven inaccurate, at least from the perspective of the origin-associated distribution of CRC metastases in the liver lobes, and therefore bears no clear predictive value. Further research under different perspectives is essential for determining more definite conclusions. Full article

The Sacramento–San Joaquin Delta (Delta) is a critical hub of California’s statewide water distribution system. Located at the confluence of California’s two largest rivers, the Sacramento River and the San Joaquin River, the Delta features a complex network of braided channels and over a hundred islands, most of which are located below sea level. The Delta’s complex nature and low-lying topography make it a unique hydrological area pertinent to climate change studies. This paper aims to estimate and explore the potential effects of climate change on the hydrological features of the Delta, especially Net Channel Depletion (NCD), which is one of the main contributors to the Net Delta Outflow (NDO). Downscaled CMIP6 General Circulation Model outputs are used to generate plausible future climate data. The Delta Channel Depletion model (DCD) is used to simulate daily hydrological processes for 61 plausible future climate scenarios. Simulation models are applied to the historical period (1930–2014) and projected future periods (2016–2100). A thorough water balance is computed in the DCD simulation model, offering insights into various elements in the hydrological cycle. Key hydrological features such as crop evapotranspiration, seepage, drainage, and runoff are simulated. Potential changes in NCD, calculated as the sum of diversions and seepage minus drainage, are also examined. The study identified a wide range of increases in NCD across all scenarios in the future period relative to the average of the historical period. These increases are projected to vary from 0.3% up to 20%. Moreover, a spatial analysis conducted across diverse regions of the Delta highlights notable variations in depletion across these areas. The results of this research indicate an anticipated increased stress on water resources, necessitating the adoption of innovative strategies to manage extreme events effectively and ensure the sustainability and resilience of water resource management. Full article

The requirement for the development of advanced technologies is the need to create new functional thermostable soluble polysilsesquioxanes. Combining the potential of organosilicon chemistry and the chemistry of heterocyclic compounds is a promising direction for the formation of novel organosilicon polymer systems with new properties and new possibilities for their practical application. Using the classical method of hydrolysis and polycondensation of previously unknown trifunctional (trimethoxysilylpropyl)glutarimide in the presence or absence of an acid or base catalyst, a universal approach to the formation of new thermostable soluble polysilsesquioxanes with glutarimide side-chain groups is proposed, which forms the basis for the synthesis of polysilsesquioxane polymers with different functionality. The weight average molecular weight of silsesquioxanes, determined by gel permeation chromatography, is practically independent of the reaction conditions and is 10–12 kDa; at the same time, the molecular weight distribution remains low and amounts to 1.38–1.47. According to thermogravimetric analysis, the resulting polysiloxanes have high thermal stability up to 335 °C. By the dynamic light scattering method, it was established that in an aqueous solution, silsesquioxane macromolecules are in an associated state, forming supramolecular structures due to the intermolecular interaction of individual macromolecules. The average hydrodynamic diameter of the particles was 46 nm. X-ray diffraction analysis showed the amorphous nature of the polymer. Polymer film coatings based on synthesized silsesquioxanes are characterized by 98% transmission in the visible spectrum and resistance to ultraviolet radiation, which is promising for the creation of functional transparent film coatings. Full article

In the Ni-Ti shape memory alloy system, Cu elements are used to replace Ni elements. A NiTiCu alloy with a molar ratio of 45:50:5 was prepared using laser selective melting technology. The density, composition, microstructure, and mechanical properties of the NiTiCu alloy were investigated. The results indicate that the highest density, exceeding 99.7%, was achieved when processing NiTiCu with parameters of 115 mm/s and 90 W. X-ray diffraction (XRD) analysis revealed that the primary phases of the sample are B2 and a minor amount of NiTi0.8Cu0.2. Energy-dispersive X-ray spectroscopy (EDS) observations of the NiTiCu alloy in the X-Y and X-Z planes show that Ni, Ti, and Cu elements are distributed nearly uniformly. Electron backscatter diffraction (EBSD) analysis revealed fine grain sizes, with grain sizes ranging from 140 μm to 160 μm. The X-Y plane predominantly exhibits equiaxed grains with a grain orientation between <111> and <101>, and a texture strength of 1.312; the X-Z plane predominantly exhibits columnar grains with grain orientations between <001> and <101>, and a texture strength of 1.427. The sample demonstrates good mechanical properties at room temperature, with a tensile strength of 375 MPa, exhibiting a ductile–brittle mixed fracture mode. The average microhardness is 240 HV for the X-Y plane and 235 HV for the X-Z plane. Full article

Background: The adolescent- and youth-friendly services (AYFS) programme has the potential to address several diverse problems within adolescents’ healthcare systems by improving the quality, accessibility, efficiency, and effectiveness of healthcare services. The country continues to suffer from structural and systemic factors that hinder the effective provision and implementation of AYFS despite its comprehensive legal and policy framework and commitment to enhancing young people’s health. Vhembe District has not been evaluated regarding the implementation of AYFS based on WHO global standards. Therefore, the objective of this study was to evaluate the implementation of AYFS against the World Health Organization (WHO) global standards for quality healthcare services for adolescents to strengthen these services in Vhembe District, Limpopo. Methods: A cross-sectional study was used to evaluate the implementation of AYFS against the WHO global standards for quality healthcare services for adolescents in Vhembe District, Limpopo. Evaluating the implementation of AYFS was conducted through questionnaires distributed to healthcare providers in the selected primary healthcare facilities in Vhembe District. For descriptive statistical analysis, research data were analysed using Statistical Package for the Social Sciences (SPSS). Results: The AYFS have been evaluated in depth across eight WHO global standards for quality health-care services for adolescents, with areas of success and areas for improvement identified. Provider competency reveals a disparity, with a majority (67.0%) of healthcare providers trained in effective communication with adolescents. In comparison, significantly fewer have received specific training in AYFS (16%) or on Pre-Exposure Prophylaxis (PrEP) (25.9%), underscoring the need for a more balanced approach to training focus. Conclusion: Research findings highlight the strengths and gaps of AYFS in Vhembe District, aligned with government and WHO priorities for adolescent health. Addressing the identified gaps is vital to ensuring that healthcare facilities are adolescent- and youth-friendly, easily accessible, and can be implemented effectively to address adolescent and youth health challenges in Vhembe District. Full article

The Chinese sturgeon (Acipenser sinensis) is an ancient, complex autooctoploid fish species that is currently facing conservation challenges throughout its distribution. To comprehensively characterize the expression profiles of genes and their associated biological functions across different tissues, we performed a transcriptome-scale gene expression analysis, focusing on housekeeping genes (HKGs), tissue-specific genes (TSGs), and co-expressed gene modules in various tissues. We collected eleven tissues to establish a transcriptomic repository, including data from Pacific Biosciences isoform sequencing (PacBio Iso-seq) and RNA sequencing (RNA-seq), and then obtained 25,434 full-length transcripts, with lengths from 307 to 9515 bp and an N50 of 3195 bp. Additionally, 20,887 transcripts were effectively identified and classified as known homologous genes. We also identified 787 HKGs, and the number of TSGs varied from 25 in the liver to 2073 in the brain. TSG functions were mainly enriched in certain signaling pathways involved in specific physiological processes, such as voltage-gated potassium channel activity, nervous system development, glial cell differentiation in the brain, and leukocyte transendothelial migration in the spleen and pronephros. Meanwhile, HKGs were highly enriched in some pathways involved in ribosome biogenesis, proteasome core complex, spliceosome activation, elongation factor activity, and translation initiation factor activity, which have been strongly implicated in fundamental biological tissue functions. We also predicted five modules, with eight hub genes in the brown module, most of which (such as rps3a, rps7, rps23, rpl11, rpl17, rpl27, and rpl28) were linked to ribosome biogenesis. Our results offer insights into ribosomal proteins that are indispensable in ribosome biogenesis and protein synthesis, which are crucial in various cell developmental processes and neural development of Chinese sturgeon. Overall, these findings will not only advance the understanding of fundamental biological functions in Chinese sturgeon but also supply a valuable genetic resource for characterizing this extremely important species. Full article

Background/Objectives: Co-delivering dual-drug systems have proven to be effective in, for example, anticancer therapy or HIV prophylaxis due to a higher target selectivity and therapeutic efficacy from compound synergism. However, various challenges regarding physical stability can arise during the formulation definition when multiple drug compounds are included in the same formulation. In this work, the focus was on aqueous suspensions, which could be applied as long-acting injectable formulations to release the drug compounds over weeks to months after administration. Methods: It was possible to gain insights into dual-drug nano- and microsuspensions containing two acidic compounds (indomethacin and naproxen) prepared by milling with dual centrifugation. Information regarding the physical stability of individual suspensions was subtracted and compared to dual-drug suspensions when prepared with the same milling conditions and stored at elevated temperatures of 40 °C. Results: Distinct particle size profiles after milling were obtained dependent on the stabilizer used in both individual and dual-drug suspensions. Most notably, the combination of indomethacin and naproxen in one formulation resulted in smaller sizes of drug particles compared to individual suspensions under the presence of some stabilizers. The obtained particle size profiles further indicated that at least one of the model compounds needed to be sufficiently stabilized from a stabilizer to obtain physically stable dual-drug suspensions over 28 days when stored at 40 °C. Similarly, the particle size distribution was dependent on the individual distribution of the suspensions, which showed a monomodal distribution could be achieved for dual-drug suspensions when at least one of the individual suspensions demonstrated a monomodal distribution in the presence of the stabilizer alone. Over a 28-day period, the smallest particle size was obtained in dual-drug suspensions stabilized with a combination of polysorbate 85 and poloxamer 338 compared to dual-drug suspensions stabilized with only a single stabilizer during preparation, indicating tendencies towards stabilization synergism from a combination of stabilizers as well as the model compounds. Conclusion: Overall, the study showed insights into the preparation and physical stability of dual-drug suspensions containing indomethacin and naproxen. Full article

Energy transition strategies point to energy systems that rely mostly on renewable sources, with photovoltaics being the most commonly used and emphasised. The transition from the past to the future of electrical system is characterised by the contrast between centralised and distributed generation, as well as the differences between synchronous machines and static converters and thus by their way to deliver services required for proper system operation, frequency regulation and transient stability. This paper compares the two converter control strategies, grid following and grid forming, for providing frequency regulation service while considering bulk photovoltaic generation at the HV level and MV-connected distributed by PV generation. The analyses reveal the equivalence between large plants and distributed resources for frequency regulation purposes, highlighting the relevance of grid-forming converter and their ability to supply inertia to the system. These results are obtained for the IEEE 14-bus system implemented in Dig Silent PowerFactory. Full article