bluuebunny/crossref_metadata_2025 huggingface dataset:
Vulnerability of Coastal Infrastructure and Communities to Extreme Storms and Rising Sea Levels: An Improved Model for Grenada and Its Dependencies
Authors: Posen Paulette E. , Beraud Claire , Harper Jones Cherry , Tyllianakis Emmanouil , Joseph-Witzig Andre , St. Louis Aria
Published: July 2023

Coastal areas of Grenada in the south-eastern Caribbean are particularly vulnerable to the adverse impacts of climate change. The effects of increasingly powerful hurricanes, sea-level rise, and reef degradation are often compounded by local anthropogenic activities. Many communities reside in low-lying areas, with development and infrastructure concentrated along the coast. Wave/storm surge models based on historic hurricanes Ivan and Lenny, and a hurricane with a predicted 100-year return period, were used to assess coastal inundation under different storm and sea-level rise scenarios. Coupled Tomawac and Telemac models were used in conjunction with high-resolution LiDAR data to provide a full vulnerability assessment across all coastal zones. Results were combined with census data at the Enumeration District level to assess impacts on the built environment. Qualitative and quantitative estimates were derived for the impact on natural features, land use, and infrastructure supporting critical economic activity in Grenada’s coastal zones. Estimation of both spatial extent and inundation depth improved the estimation of likely coastal impacts and associated costs at the national level. A general increase in extent and severity of inundation was predicted with projected future sea-level rise, with the potential for disruption to major coastal infrastructure evident in all scenarios, risking serious social and economic consequences for local communities. Coastal communities using poorer-quality building materials were most severely affected. This integrated method of assessment can guide disaster planning and decision-making to reduce risk and aid resilience in hurricane-prone regions.
Analysis of High-Quality Tourism Destinations Based on Spatiotemporal Big Data—A Case Study of Urumqi
Authors: Chen Bing , Zhu Yiting , He Xiong , Zhou Chunshan
Published: July 2023

Although high-quality tourism destinations directly determine the tourism experiences of tourists and the management focuses of tourism management departments, existing studies have paid little attention to the relationship between tourism destinations of differing quality and tourist experiences. This study analyzed the spatiotemporal distribution of tourists and the quality of tourism destinations in Urumqi based on Tencent migration big data and Weibo sign-in big data and ultimately determined whether there are spatial correlations between the two. The results show that there are large differences in quality between different tourist destinations, and although the spatial and temporal distribution of tourists is not strongly correlated with the quality of tourist destinations, we can divide tourist destinations into four categories based on the correlations between the two (e.g., high-quality tourist destinations with a low number of tourists). The results of this study provide tourists with examples of high-quality tourist destinations, thus improving their holiday experiences, and they also provide a basis by which tourism management departments can manage and develop tourist destinations. The results of this study can also be extended to other regions and play a positive role in promoting the development of the tourism industry.
A Planning Framework for Robotic Insertion Tasks via Hydroelastic Contact Model
Authors: Yang Lin , Ariffin Mohammad Zaidi , Lou Baichuan , Lv Chen , Campolo Domenico
Published: July 2023

Robotic contact-rich insertion tasks present a significant challenge for motion planning due to the complex force interaction between robots and objects. Although many learning-based methods have shown success in contact tasks, most methods need sampling or exploring to gather sufficient experimental data. However, it is both time-consuming and expensive to conduct real-world experiments repeatedly. On the other hand, while the virtual world enables low cost and fast computations by simulators, there still exists a huge sim-to-real gap due to the inaccurate point contact model. Although finite element analysis might generate accurate results for contact tasks, it is computationally expensive. As such, this study proposes a motion planning framework with bilevel optimization to leverage relatively accurate force information with fast computation time. This framework consists of Dynamic Movement Primitives (DMPs) used to parameterize motion trajectories, Black-Box Optimization (BBO), a derivative-free approach, integrated to improve contact-rich insertion policy with hydroelastic contact model, and simulated variability to account for visual uncertainty in the real world. The accuracy of the simulated model is then validated by comparing our contact results with a benchmark Peg-in-Hole task. Using these integrated DMPs and BBO with hydroelastic contact model, the motion trajectory generated in planning is capable of guiding the robot towards successful insertion with iterative refinement.
Posner’s Theorem and ∗-Centralizing Derivations on Prime Ideals with Applications
Authors: Ali Shakir , Alsuraiheed Turki M. , Khan Mohammad Salahuddin , Abdioglu Cihat , Ayedh Mohammed , Rafiquee Naira N.
Published: July 2023

A well-known result of Posner’s second theorem states that if the commutator of each element in a prime ring and its image under a nonzero derivation are central, then the ring is commutative. In the present paper, we extended this bluestocking theorem to an arbitrary ring with involution involving prime ideals. Further, apart from proving several other interesting and exciting results, we established the ∗-version of Vukman’s theorem. Precisely, we describe the structure of quotient ring A/L, where A is an arbitrary ring and L is a prime ideal of A. Further, by taking advantage of the ∗-version of Vukman’s theorem, we show that if a 2-torsion free semiprime A with involution admits a nonzero ∗-centralizing derivation, then A contains a nonzero central ideal. This result is in the spirit of the classical result due to Bell and Martindale (Theorem 3). As the applications, we extended and unified several classical theorems. Finally, we conclude our paper with a direction for further research.
Bifurcation Analysis in a Harvested Modified Leslie–Gower Model Incorporated with the Fear Factor and Prey Refuge
Authors: Vinoth Seralan , Vadivel R. , Hu Nien-Tsu , Chen Chin-Sheng , Gunasekaran Nallappan
Published: July 2023

Fear and prey refuges are two significant topics in the ecological community because they are closely associated with the connectivity of natural resources. The effect of fear on prey populations and prey refuges (proportional to both the prey and predator) is investigated in the nonlinear-type predator-harvested Leslie–Gower model. This type of prey refuge is much more sensible and realistic than the constant prey refuge model. Because there is less research on the dynamics of this type of prey refuge, the current study has been considered to strengthen the existing literature. The number and stability properties of all positive equilibria are examined. Since the calculations for the determinant and trace of the Jacobian matrix are quite complicated at these equilibria, the stability of certain positive equilibria is evaluated using a numerical simulation process. Sotomayor’s theorem is used to derive a precise mathematical confirmation of the appearance of saddle-node bifurcation and transcritical bifurcation. Furthermore, numerical simulations are provided to visually demonstrate the dynamics of the system and the stability of the limit cycle is discussed with the help of the first Lyapunov number. We perform some sensitivity investigations on our model solutions in relation to three key model parameters: the fear impact, prey refuges, and harvesting. Our findings could facilitate some biological understanding of the interactions between predators and prey.
Study on Vehicle Supply Chain Operation Mode Selection Based on Battery Leasing and Battery Swapping Services
Authors: Yuan Kaifu , Li Chao , Wu Guangqiang
Published: July 2023

Considering the impact of the battery leasing service and battery swapping service on the vehicle supply chain operation mode, a vehicle supply chain with a vehicle manufacturer and a battery asset company is investigated. Decision models are formulated in three cases: (a) both battery leasing and battery swapping services are provided by the vehicle manufacturer; (b) both services are provided by the battery asset company; (c) the battery swapping service is provided by the vehicle manufacturer and the battery leasing service by the battery asset company. The optimal decisions for the vehicle manufacturer and the battery asset company in the three cases are derived and compared. The results show that: (1) When the battery leasing increasing time cost coefficient is smaller, it is advisable for the vehicle manufacturer to provide both services; otherwise, the vehicle manufacturer should only provide the battery swapping service. (2) The battery asset company should actively provide-the battery swapping service, since the provision of the battery swapping service can increase its profit. (3) The mode of the vehicle manufacturer providing both services is optimal for the supply chain. (4) When the battery asset company provides battery leasing service, the vehicle manufacturer can “free ride” to enjoy the benefits of the battery asset company extending battery leasing time. (5) With the high cost of new energy vehicles (NEVs) limiting their development in China, extending the battery leasing increasing time is an effective measure to facilitate the diffusion of new energy vehicles (NEVs).
Coarse Sheaf Cohomology
Authors: Hartmann Elisa
Published: July 2023

A certain Grothendieck topology assigned to a metric space gives rise to a sheaf cohomology theory which sees the coarse structure of the space. Already constant coefficients produce interesting cohomology groups. In degree 0, they see the number of ends of the space. In this paper, a resolution of the constant sheaf via cochains is developed. It serves to be a valuable tool for computing cohomology. In addition, coarse homotopy invariance of coarse cohomology with constant coefficients is established. This property can be used to compute cohomology of Riemannian manifolds. The Higson corona of a proper metric space is shown to reflect sheaves and sheaf cohomology. Thus, we can use topological tools on compact Hausdorff spaces in our computations. In particular, if the asymptotic dimension of a proper metric space is finite, then higher cohomology groups vanish. We compute a few examples. As it turns out, finite abelian groups are best suited as coefficients on finitely generated groups.
Study on the Influence of an Under-Crossing Parallel Double-Line Shield Tunnel on the Existing Tunnel Structure
Authors: Zeng Linhai , Zhang Daobing , Lian Changjiang , Zhang Jiahua , Yin Huadong
Published: July 2023

Extra care should be taken when new tunnels pass through an existing tunnel. If it is not handled properly, this will affect the operation safety of the existing line, and bring security risks to the train’s operation. In order to study the impact of an under-crossing parallel double-line shield tunnel on the existing shield tunnel structure, the influence of tunnel construction on the deformation of overlying strata was analyzed, and the formula for estimating the formation settlement at depth Z below the surface, caused by the excavation of a double-tunnel parallel tunnel, was deduced. Then, a series of three-dimensional finite element numerical simulations were carried out. We analyzed and systematically studied the adverse effects of the tunnel structure of Guangzhou subway Line 5, caused by the tunneling of subway Line 18, evaluated its structure and operational safety, and provided suggestions for site construction. This research demonstrates the following conclusions. (1) The tunnel structures of subway Line 5 and Line 18 are mainly in the strongly weathered argillaceous siltstone stratum, and lightly weathered argillaceous siltstone stratum, respectively, and the stratum where the Line 18 tunnel is located is relatively safe. (2) According to three-dimensional finite element numerical simulation analysis, during the shield-tunneling process of subway Line 18, the maximum X horizontal displacement, the maximum Y horizontal displacement, and the maximum Z vertical displacement of the tunnel structure in subway Line 5 are 1.09, 3.50, and 4.55 mm, respectively. It is considered that the impact of the shield-tunnel penetration of subway Line 18 on the tunnel structure of subway Line 5 is relatively controllable, and does not affect the structure and operational safety. (3) It is suggested that settlement monitoring should be strengthened within the range of 12 m (about 1.5 tunnel diameter D). before and after the excavation axis of the underpass tunnel, and it is necessary to carry out local reinforcement treatment, to prevent adverse effects on the operation of the existing tunnel.
A GA-Based Scheduling Method for Civil Aircraft Distributed Production with Material Inventory Replenishment Consideration
Authors: Qi Xumai , Zhang Dongdong , Lu Hu , Li Rupeng
Published: July 2023

The production of civil aircrafts is confronted with a significant demand for the interconnectivity of production resources among distributed factories, while the complex coupling relationships among various production resources might restrict the improvement of production efficiency. Therefore, researching scheduling methods for civil aircraft distributed production is necessary, but previous studies have not taken material inventory into account sufficiently. This article proposes a scheduling method for civil aircraft distributed production that aims to minimize the production time to complete all the jobs in a large production station under the condition of material inventory replenishment. Firstly, we analyze the factors constraining civil aircraft production efficiency, and formulize the production scheduling problem into the Resource-Constrained Project Scheduling Problem model with Inventory Replenishment (RCPSP-IR). Precedence constraints and resource constraints, especially the inventory constraints, are mainly considered in RCPSP-IR. To solve the corresponding scheduling problem, the Genetic Algorithm (GA) is applied and multiple approaches are introduced to handle the complex constraints and avoid local optimum. Finally, we applied the proposed scheduling method to a case study of a jet twin-engine civil aircraft production of COMAC. The results of the case study show that the proposed method can give a nearly optimal scheduling strategy to be applied to actual civil aircraft production.
A New Semi-Inner Product and pn-Angle in the Space of p-Summable Sequences
Authors: Nur Muh , Bahri Mawardi , Islamiyati Anna , Batkunde Harmanus
Published: July 2023

In this paper, we propose a definition for a semi-inner product in the space of p-summable sequences equipped with an n-norm. Using this definition, we introduce the concepts of pn-orthogonality and the pn-angle between two vectors in the space of p-summable sequences. For the special case n = 1, these concepts are identical to previous studies. We also introduce the notion of the pn-angle between one-dimensional subspaces and arbitrary-dimensional subspaces. The authors believe that the results obtained in this paper are very significant, especially in the theory of n-normed space in functional analysis.
A Method of Qualitative Analysis for Determining Monotonic Stability Regions of Particular Solutions of Differential Equations of Dynamic Systems
Authors: Lyubimov Vladislav V.
Published: July 2023

Developing stability analysis methods for modern dynamical system solutions has been a significant challenge in the field. This study aims to formulate a qualitative analysis approach for the monotone stability region of a specific solution to a single differential equation within a dynamical system. The system in question comprises two first-order nonlinear ordinary differential equations of a particular kind. The method proposed hinges on applying elements of combinatorics to the traditional mathematical investigation of a function with a single independent variable. This approach enables the exact determination of the different qualitative scenarios in which the desired solution changes, under the assumption that the function values monotonically diminish from a specified value down to a finite zero. This paper outlines the creation and decomposition of the monotone stability region associated with the solution under consideration.
Influence of Torque on Platform Deformity of the Tri-Channel Implant: Two- and Three-Dimensional Analysis Using Micro-Computed Tomography
Authors: de Morais Renata Costa , Simionato Anselmo Agostinho , Moris Izabela Cristina Maurício , Leoni Graziela Bianchi , Faria Adriana Cláudia Lapria , Rodrigues Renata Cristina Silveira , Ribeiro Ricardo Faria
Published: July 2023

Background and Objectives: The insertion of the dental implant in the bone is an essential step in prosthetic rehabilitation. The insertion torque has the potential to distort the prosthetic platform, which can cause future biomechanical problems with the continuous action of occlusal forces. The aim of this study is to evaluate different insertion torques in the deformation of tri-channel platform connections through two- and three-dimensional measurements with micro-CT. Materials and Methods: A total of 164 implants were divided into groups (platform diameter and type): 3.5, 3.75, and 4.3 mm NP (narrow platform), and 4.3 mm RP (regular platform). Each implant–platform group was then divided into four subgroups (n = 10) with different torques: T45 (45 Ncm), T80 (80 Ncm), T120 (120 Ncm), and T150 (150 Ncm). The implant–abutment–screw assemblies were scanned and the images obtained were analyzed. Results: A significant difference was observed for the linear and volume measures between the different platforms (p < 0.01) and the different implant insertion torques (p < 0.01). Qualitative analysis suggested a higher deformation resistance for the 3.75 NP compared to the 3.5 NP, and RP was more resistant compared to the NP. Conclusions: The 0.25 mm increment in the implant platform did not increase the resistance to the applied insertion torques; the 4.3 mm implant was significantly stronger compared to the 3.5 mm implant; and the proposed micro-CT analysis was considered valid for both the 2D and 3D analyses of micro-gaps, qualitatively and quantitatively.
The Clinical Significance of LDL-Cholesterol on the Outcomes of Hemodialysis Patients with Acute Coronary Syndrome
Authors: Cohen-Hagai Keren , Benchetrit Sydney , Wand Ori , Grupper Ayelet , Shashar Moshe , Solo Olga , Pereg David , Zitman-Gal Tali , Haskiah Feras , Erez Daniel
Published: July 2023

Background and objectives: Dyslipidemia is one of the most important modifiable risk factors in the pathogenesis of cardiovascular disease in the general population, but its importance in the hemodialysis (HD) population is uncertain. Materials and Methods: This retrospective cohort study includes HD patients hospitalized due to acute coronary syndrome (ACS) in the period 2015–2020 with lipid profile data during ACS. A control group with preserved kidney function was matched. Risk factors for 30-day and 1-year mortality were assessed. Results: Among 349 patients included in the analysis, 246 were HD-dependent (“HD group”). HD group patients had higher prevalence of diabetes, hypertension, and heart disease than the control group. At ACS hospitalization, lipid profile and chronic statin treatment were comparable between groups. Odds ratios for 30-day mortality in HD vs. control group was 5.2 (95% CI 1.8–15; p = 0.002) and for 1-year, 3.4 (95% CI 1.9–6.1; p <0.001). LDL and LDL < 70 did not change 30-day and 1-year mortality rates in the HD group (p = 0.995, 0.823, respectively). However, survival after ACS in HD patients correlated positively with nutritional parameters such as serum albumin (r = 0.368, p < 0.001) and total cholesterol (r = 0.185, p < 0.001), and inversely with the inflammatory markers C-reactive protein (CRP; r = −0.348, p < 0.001) and neutrophils-to-lymphocytes ratio (NLR; r = −0.181, p = 0.019). Multivariate analysis demonstrated that heart failure was the only significant predictor of 1-year mortality (OR 2.8, p = 0.002). LDL < 70 mg/dL at ACS hospitalization did not predict 1-year mortality in the HD group. Conclusions: Despite comparable lipid profiles and statin treatment before and after ACS hospitalization, mortality rates were significantly higher among HD group. While malnutrition–inflammation markers were associated with survival of dialysis patients after ACS, LDL cholesterol was not. Thus, our study results emphasize that better nutritional status and less inflammation are associated with improved survival among HD patients.
Effect of TiC Particle Size on Processing, Microstructure and Mechanical Properties of an Inconel 718/TiC Composite Material Made by Binder Jetting Additive Manufacturing
Authors: Sufiiarov Vadim , Borisov Artem , Popovich Anatoly , Erutin Danil
Published: July 2023

In this paper, the effect of TiC particle size on the microstructure and mechanical properties of an Inconel 718/TiC composite material fabricated using binder jetting additive manufacturing was investigated. Vacuum sintering, hot isostatic pressing and heat treatment as post-processing were applied to the samples. The addition of 1 wt% micron-sized TiC to the Inconel 718 matrix resulted in a significant increase in strength and relative elongation during tensile tests at both room temperature and 700 °C. The distribution of micron-sized TiC particles in the matrix was uniform, and the MC phase precipitated after HT was located along the grain boundaries and near the micron-sized TiC particles, which contributed to the strengthening. The hardness increased insignificantly with the addition of micron-sized TiC. The nano-sized TiC particles added to the matrix were located on the surfaces of the Inconel 718 particles of the initial powders, which obstructed sintering and resulted in a porous structure and, consequently, low mechanical properties.
Experimental Study of Crack Propagation through Cladded 316L/S355 Steel Produced by the Hot-Roll Bonding Process
Authors: Bjelajac Edvard , Skumavc Andrej , Smaili Fidan , Lojen Gorazd , Predan Jožef , Vuherer Tomaž
Published: July 2023

A hot-rolled clad plate made of 316L stainless steel and S355 carbon steel was produced in a real industrial environment via GMAW welding, vacuuming, preheating to 1240 °C, and hot-roll bonding on four stand plate mills in nine passes with reduction rates between 20-6% per pass. The clad plates were solution annealed to achieve the usual delivery condition. Ultrasound testing showed a bonding rate of 100%. Metallographic examination revealed predominantly low concentrations of oxides at the interface. The tensile strength of the bond reached 155 MPa. The shear strength always satisfied the requirements of ASTM A264. It was observed that the concentration of oxide particles influenced the shear strength strongly. The lowest measured value was 172 MPa. Specimens notched in the base material and specimens notched in the clad layer were used in the Charpy impact test. In every case, only the notched layer broke, while the other layer was only bent. The absorbed energies were always higher than those of each material alone. Fracture mechanic tests gave similar results. The crack could not propagate from the notched layer into the other one, regardless of the material of the notched layer. Instead, delamination occurred. Due to delamination, K1c could not be determined, so KQ was given instead.
Numerical Simulation of Heat and Mass Transfer Behavior during Iron Ore Sintering: A Review
Authors: Liu Zhengjian , Li Zhen , Wang Yaozu , Zhang Jianliang , Wang Jiabao , Niu Lele , Li Sida , Feng Ben
Published: July 2023

Accurate computational models of sintering behavior would assist to enhance sinter quality and are anticipated to play a role in yield prediction. Sintering is a vital process in the manufacturing of iron and steel. As a consequence, the primary objective of these models will be a thorough simulation of mass and heat transport during the sintering process. In this paper, based on the examination and integration of previous studies, the fundamental physical formula and chemical reactions of the numerical simulation of the sintering process are introduced in depth with mechanism analysis. Furthermore, in view of the current numerical simulation methods and sintering process technology innovation development, the studies on sintering numerical simulation are reviewed from different angles, of which the main methods and assumptions are discussed. Finally, the current state of sintering simulation including the numerical simulation of innovative algorithm and optimized sintering technology is discussed in detail, along with potential implications for model development.
Stepwise Laser Cladding of TiNbZr and TiTaZr Medium-Entropy Alloys on Pure Ti Substrate
Authors: Lv Hao , Gao Mingyu , Liu Xinying , Liu Jiabin , Dong Weiping , Fang Youtong
Published: July 2023

This work aimed to fabricate two varieties of near-equiatomic TiNbZr and TiTaZr medium-entropy alloy (MEA) claddings on pure Ti as protective layers by stepwise laser cladding. Their stratified component distribution, microstructural characteristics, and phase constitutions were analyzed, with their hardness and wear resistance were compared with that of pristine Ti. It was found that a single body-centered-cubic solid-solution phase in both MEA claddings were realized on the hexagonal closed-packed pure Ti substrates. The subgrain structures in the TiNbZr cladding were cellular grains, while the ones in the TiTaZr cladding were much denser dendrite arms, which led to increased residual stress. The results showed that the hardness of the TiNbZr and TiTaZr claddings were 450 ± 30 HV0.2 and 513 ± 27 HV0.2, respectively, 2.6 times and 3 times that of the pure Ti (170 ± 11 HV0.2). Also, the consequent wear rates decreased from 2.08 × 10−4 mm3·N−1·m−1 (pure Ti) to 0.49 × 10−4 mm3·N−1·m−1 (TiNbZr) and 0.32 × 10−4 mm3·N−1·m−1 (TiTaZr). Such high hardness and enhanced wear resistance are attributed to the solid-solution strengthening of the body-centered-cubic phase and the residual stress in the claddings. The realization of hard MEA layers by stepwise laser cladding offers a flexible and effective way for protecting pure Ti.
The Effect of Severe Plastic Deformation on the Microstructure and Mechanical Properties of Composite from 5056 and 1580 Aluminum Alloys Produced with Wire Arc Additive Manufacturing
Authors: Mavlyutov Aydar , Evstifeev Alexey , Volosevich Darya , Gushchina Marina , Voropaev Artem , Zotov Oleg , Klimova-Korsmik Olga
Published: July 2023

In this study, a composite with alternate layers of 5056 and 1580 alloys was manufactured with wire arc additive manufacturing technology. It is shown that increased strength characteristics of composite material can be obtained with deformation treatment using a high-pressure torsion (HPT) technique. The microstructure and mechanical properties of the HPT-processed material in different structural states were investigated. The HPT-processed material exhibits a high value of ultimate tensile strength (~770 MPa) but low ductility. Short-term annealing at 250 °C and additional deformation with HPT to 0.25 of revolution at room temperature resulted in a slight decrease in the material’s strength to ~700 MPa but provided ductility of ∼9%. Physical mechanisms to improve plasticity in correlation with microstructure evolution are discussed.
Photocatalytic Degradation, Anticancer, and Antibacterial Studies of Lysinibacillus sphaericus Biosynthesized Hybrid Metal/Semiconductor Nanocomposites
Authors: Narayanan Kannan Badri , Bhaskar Rakesh , Seok Yong Joo , Han Sung Soo
Published: July 2023

The biological synthesis of nanocomposites has become cost-effective and environmentally friendly and can achieve sustainability with high efficiency. Recently, the biological synthesis of semiconductor and metal-doped semiconductor nanocomposites with enhanced photocatalytic degradation efficiency, anticancer, and antibacterial properties has attracted considerable attention. To this end, for the first time, we biosynthesized zinc oxide (ZnO) and silver/ZnO nanocomposites (Ag/ZnO NCs) as semiconductor and metal-doped semiconductor nanocomposites, respectively, using the cell-free filtrate (CFF) of the bacterium Lysinibacillus sphaericus. The biosynthesized ZnO and Ag/ZnO NCs were characterized by various techniques, such as ultraviolet-visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The photocatalytic degradation potential of these semiconductor NPs and metal-semiconductor NCs was evaluated against thiazine dye, methylene blue (MB) degradation, under simulated solar irradiation. Ag/ZnO showed 90.4 ± 0.46% photocatalytic degradation of MB, compared to 38.18 ± 0.15% by ZnO in 120 min. The cytotoxicity of ZnO and Ag/ZnO on human cervical HeLa cancer cells was determined using an MTT assay. Both nanomaterials exhibited cytotoxicity in a concentration- and time-dependent manner on HeLa cells. The antibacterial activity was also determined against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus). Compared to ZnO, Ag/ZnO NCs showed higher antibacterial activity. Hence, the biosynthesis of semiconductor nanoparticles could be a promising strategy for developing hybrid metal/semiconductor nanomaterials for different biomedical and environmental applications.
Acinetobacter baumannii Bloodstream Infections in the COVID-19 Era: A Comparative Analysis between COVID-19 and Non-COVID-19 Critically Ill Patients
Authors: Andrianopoulos Ioannis , Maniatopoulou Theodora , Lagos Nikolaos , Kazakos Nikolaos , Papathanasiou Athanasios , Papathanakos Georgios , Koulenti Despoina , Kittas Christos , Koulouras Vasilios
Published: July 2023

The coronavirus disease (COVID-19) pandemic increased the incidence of severe infections caused by multidrug-resistant (MDR) pathogens among critically ill patients, such as Acinetobacter baumannii (AB), whose bloodstream infections (BSIs) have been associated with significant mortality. Whether there is any difference in outcome between COVID-19 and non-COVID-19 patients with AB BSI still remains unknown. We conducted a retrospective study comparing clinical characteristics and outcomes of COVID-19 versus non-COVID-19 critically ill patients with AB BSI. Overall, 133 patients with AB BSI (102 COVID-19, 31 non-COVID-19) were studied. The 28-day mortality rate was high and did not differ significantly (69.6% COVID-19 vs. 61.3% non-COVID-19, p = 0.275). Patients with septic shock had a higher mortality rate irrespective of their status with the majority of deaths occurring during the first 7 days. COVID-19 patients were more likely to have ventilator-associated pneumonia (VAP) as the source of BSI (55.8% vs. 22.3%, respectively, p = 0.0001) and were more likely to develop acute respiratory distress syndrome (ARDS) (78.4% vs. 48.4%, respectively, p = 0.001), sepsis (86.3% vs. 67.7%, respectively, p = 0.03), and septic shock (88.3% vs. 58.1%, respectively, p = 0.007) compared to the non-COVID-19 patient group. In conclusion, COVID-19 patients with A. baumannii BSI have a high rate of mortality and more often develop septic shock, while VAP is the main origin of their BSI.
Effects of Algal Extracellular Polysaccharides on the Formation of Filamentous Manganese Oxide Particles in the Near-Bottom Layer of Lake Biwa
Authors: Furuta Seiko , Ikegaya Hisato , Fujibayashi Megumu , Hashimoto Hideki , Suzuki Shiro , Okano Kunihiro , Ichise Satoshi , Miyata Naoyuki
Published: July 2023

Filamentous manganese (Mn) oxide particles, which occur in the suboxic zone of stratified waterbodies, are important drivers of diverse elemental cycles. These particles are considered to be bacteriogenic; despite the importance of biogeochemical implications, however, the environmental factor responsible for their formation has not been identified. The aim of this study was to demonstrate the involvement of algal extracellular polysaccharides in Mn oxide particle formation. Based on this study of laboratory cultures of a model Mn(II)-oxidizing bacterium, the supply of algal extracellular mucilage was shown to stimulate Mn(II) oxidation and thus the production of filamentous Mn oxide particles. This observation was consistent with the results obtained for naturally occurring particles collected from a near-bottom layer (depth of approximately 90 m) in the northern basin of Lake Biwa, Japan, that is, most Mn particles resembling δ-MnO2 were associated with an extracellular mucilage-like gelatinous matrix, which contained dead algal cells and was lectin-stainable. In the lake water column, polysaccharides produced by algal photosynthesis sank to the bottom layer. The analysis of the quality of water samples, which have been collected from the study site for 18 years, reveals that the annual average total phytoplankton biovolume in the surface layer correlates with the density of filamentous Mn particles in the near-bottom layer. Among different phytoplankton species, green algae appeared to be the key species. The results of this study suggest that algal extracellular polysaccharides serve as an important inducer for the formation of filamentous Mn oxide particles in the near-bottom layer of the northern basin of Lake Biwa.
Hydrogel-Containing Biogenic Silver Nanoparticles: Antibacterial Action, Evaluation of Wound Healing, and Bioaccumulation in Wistar Rats
Authors: Scandorieiro Sara , Kimura Angela Hitomi , de Camargo Larissa Ciappina , Gonçalves Marcelly Chue , da Silva João Vinícius Honório , Risso Wagner Ezequiel , de Andrade Fábio Goulart , Zaia Cássia Thaïs Bussamra Vieira , Lonni Audrey Alesandra Stinghen Garcia , dos Reis Martinez Claudia Bueno , Durán Nelson , Nakazato Gerson , Kobayashi Renata Katsuko Takayama
Published: July 2023

Wound infections are feared complications due to their potential to increase healthcare costs and cause mortality since multidrug-resistant bacteria reduce treatment options. This study reports the development of a carbomer hydrogel containing biogenic silver nanoparticles (bioAgNPs) and its effectiveness in wound treatment. This hydrogel showed in vitro bactericidal activity after 2 h, according to the time–kill assay. It also reduced bacterial contamination in rat wounds without impairing their healing since the hydrogel hydrophilic groups provided hydration for the injured skin. The high number of inflammatory cells in the first days of the skin lesion and the greater degree of neovascularization one week after wound onset showed that the healing process occurred normally. Furthermore, the hydrogel-containing bioAgNPs did not cause toxic silver accumulation in the organs and blood of the rats. This study developed a bioAgNP hydrogel for the treatment of wounds; it has a potent antimicrobial action without interfering with cicatrization or causing silver bioaccumulation. This formulation is effective against bacteria that commonly cause wound infections, such as Pseudomonas aeruginosa and Staphylococcus aureus, and for which new antimicrobials are urgently needed, according to the World Health Organization’s warning.
Association between High Interferon-Gamma Production in Avian Tuberculin-Stimulated Blood from Mycobacterium avium subsp. paratuberculosis-Infected Cattle and Candidate Genes Implicated in Necroptosis
Authors: Badia-Bringué Gerard , Canive María , Vázquez Patricia , Garrido Joseba M. , Fernández Almudena , Juste Ramón A. , Jiménez José Antonio , González-Recio Oscar , Alonso-Hearn Marta
Published: July 2023

The mechanisms underlying host resistance to Mycobacterium avium subsp. paratuberculosis (MAP) infection are largely unknown. In the current study, we hypothesize that cows with an ability to produce higher levels of interferon-gamma (IFNɣ) might control MAP infection more successfully. To test this hypothesis, IFNɣ production was measured using a specific IFNɣ ELISA kit in avian purified protein derivative (aPPD)-stimulated blood samples collected from 152 Holstein cattle. DNA isolated from peripheral blood samples of the animals included in the study was genotyped with the EuroG Medium-Density Bead Chip, and the genotypes were imputed to whole-genome sequencing. A genome-wide association analysis (GWAS) revealed that high levels of IFNɣ in response to the aPPD were associated with a specific genetic profile (heritability = 0.64) and allowed the identification of 71 SNPs, 40 quantitative trait loci (QTL), and 104 candidate genes. A functional analysis using the 104 candidate genes revealed a significant enrichment of genes involved in the innate immune response and, more specifically, in necroptosis. Taken together, our results define a heritable and distinct immunogenetic profile associated with the production of high IFNɣ levels and with the capacity of the host to lyse MAP-infected macrophages by necroptosis.
Changes in the Microbial Composition of the Rhizosphere of Hop Plants Affected by Verticillium Wilt Caused by Verticillium nonalfalfae
Authors: Gallego-Clemente Elena , Moreno-González Víctor , Ibáñez Ana , Calvo-Peña Carla , Ghoreshizadeh Seyedehtannaz , Radišek Sebastjan , Cobos Rebeca , Coque Juan José R.
Published: July 2023

Verticillium wilt is a devastating disease affecting many crops, including hops. This study aims to describe fungal and bacterial populations associated with bulk and rhizosphere soils in a hop field cultivated in Slovenia with the Celeia variety, which is highly susceptible to Verticillium nonalfalfae. As both healthy and diseased plants coexist in the same field, we focused this study on the detection of putative differences in the microbial communities associated with the two types of plants. Bacterial communities were characterized by sequencing the V4 region of the 16S rRNA gene, whereas sequencing of the ITS2 region was performed for fungal communities. The bacterial community was dominated by phyla Proteobacteria, Acidobacteriota, Bacteroidota, Actinobacteriota, Planctomycetota, Chloroflexi, Gemmatimonadota, and Verrucomicrobiota, which are typically found in crop soils throughout the world. At a fungal level, Fusarium sp. was the dominant taxon in both bulk and rhizosphere soils. Verticillium sp. levels were very low in all samples analyzed and could only be detected by qPCR in the rhizosphere of diseased plants. The rhizosphere of diseased plants underwent important changes with respect to the rhizosphere of healthy plants where significant increases in potentially beneficial fungi such as the basidiomycetes Ceratobasidium sp. and Mycena sp., the zygomycete Mortierella sp., and a member of Glomeralles were observed. However, the rhizosphere of diseased plants experienced a decrease in pathogenic basidiomycetes that can affect the root system, such as Thanatephorus cucumeris (the teleomorph of Rhizoctonia solani) and Calyptella sp.
The Volatile Organic Compounds of Streptomyces spp.: An In-Depth Analysis of Their Antifungal Properties
Authors: Cuervo Lorena , Álvarez-García Samuel , Salas José A. , Méndez Carmen , Olano Carlos , Malmierca Mónica G.
Published: July 2023

The study of volatile organic compounds (VOCs) has expanded because of the growing need to search for new bioactive compounds that could be used as therapeutic alternatives. These small molecules serve as signals to establish interactions with other nearby organisms in the environment. In this work, we evaluated the antifungal effect of VOCs produced by different Streptomyces spp. This study was performed using VOC chamber devices that allow for the free exchange of VOCs without physical contact between microorganisms or the diffusible compounds they produce. Antifungal activity was tested against Escovopsis weberi, a fungal pathogen that affects ant nest stability, and the results showed that Streptomyces spp. CS014, CS057, CS131, CS147, CS159, CS207, and CS227 inhibit or reduce the fungal growth with their emitted VOCs. A GS-MS analysis of volatiles produced and captured by activated charcoal suggested that these Streptomyces strains synthesize several antifungal VOCs, many of them produced because of the presence of E. weberi, with the accumulation of various VOCs determining the growth inhibition effect.
Volatile Organic Compound Assessment as a Screening Tool for Early Detection of Gastrointestinal Diseases
Authors: Dalis Costa , Mesfin Fikir M. , Manohar Krishna , Liu Jianyun , Shelley W. Christopher , Brokaw John P. , Markel Troy A.
Published: July 2023

Gastrointestinal (GI) diseases have a high prevalence throughout the United States. Screening and diagnostic modalities are often expensive and invasive, and therefore, people do not utilize them effectively. Lack of proper screening and diagnostic assessment may lead to delays in diagnosis, more advanced disease at the time of diagnosis, and higher morbidity and mortality rates. Research on the intestinal microbiome has demonstrated that dysbiosis, or unfavorable alteration of organismal composition, precedes the onset of clinical symptoms for various GI diseases. GI disease diagnostic research has led to a shift towards non-invasive methods for GI screening, including chemical-detection tests that measure changes in volatile organic compounds (VOCs), which are the byproducts of bacterial metabolism that result in the distinct smell of stool. Many of these tools are expensive, immobile benchtop instruments that require highly trained individuals to interpret the results. These attributes make them difficult to implement in clinical settings. Alternatively, electronic noses (E-noses) are relatively cheaper, handheld devices that utilize multi-sensor arrays and pattern recognition technology to analyze VOCs. The purpose of this review is to (1) highlight how dysbiosis impacts intestinal diseases and how VOC metabolites can be utilized to detect alterations in the microbiome, (2) summarize the available VOC analytical platforms that can be used to detect aberrancies in intestinal health, (3) define the current technological advancements and limitations of E-nose technology, and finally, (4) review the literature surrounding several intestinal diseases in which headspace VOCs can be used to detect or predict disease.
Polyphenols and Neurodegenerative Diseases: Potential Effects and Mechanisms of Neuroprotection
Authors: Arias-Sánchez Raziel Alejandro , Torner Luz , Fenton Navarro Bertha
Published: July 2023

The increase in people’s longevity has, consequently, led to more brain involvement and neurodegenerative diseases, which can become complicated and lead to chronic degenerative diseases, thereby presenting greater public health problems. Medicinal plants have been used since ancient times and contain high concentrations of molecules, including polyphenols. It has been proven that polyphenols, which are present in various natural sources can provide curative effects against various diseases and brain disorders through neuroprotective effects. These neuroprotective effects are mainly attributed to their ability to cross the blood–brain barrier, eliminate reactive oxygen species, and cause the chelation of metal ions. Polyphenols increase the concentration of neurotrophic factors and bind directly to the membrane receptors of these neurotrophic factors, to modulate and activate the signaling cascades that allow the plasticity, survival, proliferation, and growth of neuronal cells, thereby allowing for better learning, memory, and cognition. Moreover, polyphenols have no serious adverse side effects resulting from their consumption.
Cellular, Molecular, Pharmacological, and Nano-Formulation Aspects of Thymoquinone—A Potent Natural Antiviral Agent
Authors: Shoaib Ambreen , Javed Shamama , Wahab Shadma , Azmi Lubna , Tabish Mohammad , Sultan Muhammad H. , Abdelsalam Karim , Alqahtani Saad S. , Ahmad Md Faruque
Published: July 2023

The goal of an antiviral agent research is to find an antiviral drug that reduces viral growth without harming healthy cells. Transformations of the virus, new viral strain developments, the resistance of viral pathogens, and side effects are the current challenges in terms of discovering antiviral drugs. The time has come and it is now essential to discover a natural antiviral agent that has the potential to destroy viruses without causing resistance or other unintended side effects. The pharmacological potency of thymoquinone (TQ) against different communicable and non-communicable diseases has been proven by various studies, and TQ is considered to be a safe antiviral substitute. Adjunctive immunomodulatory effects in addition to the antiviral potency of TQ makes it a major compound against viral infection through modulating the production of nitric oxide and reactive oxygen species, decreasing the cytokine storm, and inhibiting endothelial dysfunction. Nevertheless, TQ’s low oral bioavailability, short half-life, poor water solubility, and conventional formulation are barriers to achieving its optimal pharmacologic benefits. Nano-formulation proposes numerous ways to overcome these obstacles through a small particle size, a big surface area, and a variety of surface modifications. Nano-based pharmaceutical innovations to combat viral infections using TQ are a promising approach to treating surmounting viral infections.
Editorial for Special Issue—‘’Research Progress and Applications of Natural Products”
Authors: Lungu Claudiu N. , Mangalagiu Ionel
Published: July 2023

This Special Issue (S [...]
Catalyzing Benzoxazine Polymerization with Titanium-Containing POSS to Reduce the Curing Temperature and Improve Thermal Stability
Authors: Sun Xiaoyi , Fu Qixuan , Dai Pei , Zhang Caili , Xu Riwei
Published: July 2023

Trisilanolphenyl-polyhedral oligomeric silsesquioxane titanium (Ti-Ph-POSS) was synthesized through the corner-capping reaction, and Ti-Ph-POSS was dispersed in benzoxazine (BZ) to prepare Ti-Ph-POSS/PBZ composite materials. Ti-Ph-POSS could catalyze the ring-opening polymerization (ROP) of BZ and reduce the curing temperature of benzoxazine. In addition, Ti immobilized on the Ti-Ph-POSS cage could form covalent bonds with the N or O atoms on polybenzoxazine, improving the thermal stability of PBZ. The catalytic activity of the Ti-Ph-POSS/BZ mixtures was assessed and identified through 1H nuclear magnetic resonance (1H-NMR) and Fourier-transform infrared (FTIR) analyses, while thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) were used to determine the thermal properties of the composite. It was found that PBZ exhibited a higher glass transition temperature (Tg) and better thermal stability when Ti-Ph-POSS was added. The curing behavior of the Ti-Ph-POSS/BZ mixtures showed that the initial (Ti) and peak (Tp) curing temperatures sharply decreased as the content of Ti-Ph-POSS and the heating rate increased. The curing kinetics of these Ti-Ph-POSS/BZ systems were analyzed using the Kissinger method, and the morphology of Ti-Ph-POSS/PBZ was determined via scanning electron microscopy (SEM). It was found that the Ti-Ph-POSS particles were well distributed in the composites. When the content exceeded 2 wt%, several Ti-Ph-POSS particles could not react with benzoxazine and were only dispersed within the PBZ matrix, resulting in aggregation of the Ti-Ph-POSS molecules.