bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of Long-Term Performance and Deicing Longevity Prediction of Self-Ice-Melting Asphalt Pavement
Authors: Zhang Haihu , Guo Runhua
Published: September 2022

Based on laboratory tests, the objective of this study is to assess long-term road performance and to predict deicing longevity of self-ice-melting asphalt pavements containing salt-storage materials. Dry–wet cycles and freeze–thaw cycles were used to treat the specimens at different durations. The long-term road performance of self-ice-melting asphalt mixtures was evaluated by freeze–thaw splitting tests, high-temperature rutting tests, and low-temperature beam bending tests. In addition, the influences of coefficients of void ratio, temperature, vehicle load, crack, and Mafilon (MFL) content on salt precipitation were quantified by conductivity tests, and single consumption of snow and ice melt was quantified by total dissolved solids (TDS) tests. The results show that the long-term water stability, long-term high-temperature stability, and long-term low-temperature crack resistance of self-ice-melting asphalt pavements tended to decrease as the number of dry–wet cycles and freeze–thaw cycles increased. Freeze–thaw cycles exerted deeper influences on the deterioration of road performance than dry–wet cycles, especially on water stability. With increased void ratio and temperature, salt precipitation was accelerated by 1.1 times and 1.5~1.8 times, respectively. Under vehicle loads and cracks, salt precipitation was accelerated by 1.5 times and 1.65 times, respectively. With decreased MFL content, salt precipitation slowed down by 0.54 times. Finally, based on the proportion of each factor relative to the whole life cycle of the pavement, a dicing longevity prediction model was established considering the above factors.
Experimental Study on the Influence of a Two-Dimensional Cosine Hill on Wind Turbine Wake
Authors: Yang Junwei , Feng Keru , Yang Hua , Wang Xiangjun
Published: September 2022

The accurate prediction of wind energy distribution on the terrain has been of great significance for wind farm selection. Therefore, this paper evaluated the influence of a two-dimensional hill with a relatively large slope (i.e., 0.83) on wind turbine wake. Firstly, the wakes on flat terrain and wind characteristics around a single hill were investigated by using a hot-wire anemometer. Subsequently, wake distributions combined with the hill were measured when the turbine was located 2D in front and on the hilltop. The results of the hill showed that a flow separation was formed within 6D of the leeward side (where D is the rotor diameter). The turbulence intensity increased initially and then decreased as height increased, leading to a high turbulence region 2.28 times the hill height, according to the experiment of a wind turbine combined with the hill. In conclusion, wake recovery was promoted on the windward side and 4D behind the hilltop. As the longitudinal coordinate increased, the intensity of the turbulence changed to a single peak, and the peak value was more than twice as high as on flat terrain. Based on this, it may be possible to optimize the design of wind turbines for better performance.
Development of a Novel Underactuated Robotic Fish with Magnetic Transmission System
Authors: Romano Donato , Wahi Akshat , Miraglia Marco , Stefanini Cesare
Published: September 2022

In this study, a robotic fish inspired to carangiform swimmers has been developed. The artifact presents a new transmission system that employs the magnetic field interaction of permanent magnets to ensure waterproofness and prevention from any overload for the structure and the actuating motor. This mechanism converts the rotary motion of the motor into oscillatory motion. Such an oscillating system, along with the wire-driven mechanism of the tail, generates the required traveling wave in the robotic fish. The complete free swimming robotic fish, measuring 179 mm in length with a mass of only 77 g, was able to maintain correct posture and neutral buoyancy in water. Multiple experiments were conducted to test the robotic fish performance. It could swim with a maximal speed of 0.73 body lengths per second (0.13 m/s) at a tail beat frequency of 3.25 Hz and an electric power consumption of 0.67 W. Furthermore, the robotic fish touched the upper bound of the efficient swimming range, expressed by the dimensionless Strouhal number: 0.43 at 1.75 Hz tail beat frequency. The lowest energy to travel 1 meter was 4.73 Joules for the final prototype. Future works will focus on endowing the robot with energy and navigation autonomy, and on testing its potential for real-world applications such as environmental monitoring and animal–robot interaction.
A Comprehensive Analysis of Radiosensitization Properties of Metallic Nanoparticles in Brachytherapy of Gastric Adenocarcinoma by I-125 Seed: A Simulation Study by MCNPX and MCNP6 Codes
Authors: Mansouri Elham , Mesbahi Asghar , Hejazi Mohammad Saeid , Tarhriz Vahideh , Hamishehkar Hamed , Seyednejad Farshad
Published: September 2022

Purpose: In the current study, we aimed to look into the macroscopic and microscopic dose enhancement effect of metallic nanoparticles in interstitial brachytherapy of gastric adenocarcinoma by Iodine-125 source using a nano-lattice model in MCNPX (2.7) and MCNP6.1 codes. Materials and methods: Based on a nano-lattice simulation model containing a radiation source and a tumor tissue with cellular compartments loaded with 7 mg/g spherical nanoparticles, the microscopic and macroscopic levels of energy deposition by the secondary electrons was estimated. Results: The results show that the values of macroscopic DEF are higher than microscopic DEF values and the macroscopic DEF values decrease by increasing the distance from the surface of brachytherapy source. Accordingly, it could be noted that gold nanoparticles have the highest radiosensitization effect among the other nanoparticles and the related DEF value is close to the resultant DEF values for bismuth nanoparticles. Moreover, the results revealed a remarkable discrepancy between the DEF and secondary electron spectra calculated by MCNPX (2.7) and MCNP6.1 codes, which could be justified by the difference in energy cut-off and electron transport algorithms of two codes. Conclusions: According to the both MCNPX (2.7) and MCNP6.1 outputs, it could be concluded that the presence of metallic nanoparticles in the tumor tissue of gastric adenocarcinoma increases the physical effectiveness of brachytherapy by I-125 source. This study aims to provide recommendations for future preclinical studies. Actually, the results presented herein give a physical view of radiosensitization potential of different metallic nanoparticles and could be considered in design of analytical and experimental radiosensitization studies in tumor regions using various radiotherapy modalities in the presence of heavy nanomaterials.
Bayesian Estimation Using MCMC Method of System Reliability for Inverted Topp–Leone Distribution Based on Ranked Set Sampling
Authors: Yousef Manal M. , Hassan Amal S. , Al-Nefaie Abdullah H. , Almetwally Ehab M. , Almongy Hisham M.
Published: September 2022

The current work focuses on ranked set sampling and a simple random sample as sampling approaches for determining stress–strength reliability from the inverted Topp–Leone distribution. Asymptotic confidence intervals are established, along with a maximum likelihood estimator of the parameters and stress–strength reliability. The reliability of such a system is assessed using the Bayesian approach under symmetric and asymmetric loss functions. The highest posterior density credible interval is constructed successively. The results are extracted using Monte Carlo simulation to compare the proposed estimators performance with different sample sizes. Finally, by looking at waiting time data and failure times of insulating fluid, the usefulness of the suggested technique is demonstrated.
COVID-19 Pandemic and Its Impact on Challenges in the Construction Sector: A Case Study of Slovak Enterprises
Authors: Gajdosikova Dominika , Valaskova Katarina , Kliestik Tomas , Machova Veronika
Published: September 2022

The corona crisis has affected not only the economic sphere, but also the sphere of health, health care, employment, safety, and health protection in the workplace, shopping habits, and future expectations, to which people adapt their decisions in various areas of daily life. The COVID-19 pandemic, called a global health crisis, was an unpredictable risk of global proportions that paralyzed the entire world. The main aim of this paper is to quantify the impacts of the COVID-19 pandemic on the construction sector, which is considered a crucial sector of the Slovak economy, to evaluate changes in the development of key indicators using adequate quantitative methods. First, a sample of 2000 businesses were analyzed using the 12 financial indicators that were chosen. Second, using the non-parametric Friedman test, a more thorough study was carried out with a focus on analyzing the existence of statistically significant variations in the values of computed indicators as a result of changes in the development of key financial ratios. The Bonferroni adjustments were employed to pinpoint the areas of stochastic dominance at the conclusion of the study. A detailed analysis of the calculated financial indicators showed that the arrival of the pandemic had a negative impact on many aspects of business in the construction sector and affected the financial and economic situation of companies in the construction sector of the Slovak Republic. However, due to the fact that this sector is characterized by slower reactions to changes in the economy, the most significant impacts will be even more noticeable in the future.
Extension Design Pattern of Requirement Analysis for Complex Mechanical Products Scheme Design
Authors: Wang Tichun , Li Hao , Wang Xianwei
Published: September 2022

Due to the configuration process of a complex product scheme, a design structure often has the characteristics of multi-level, multi-attribute, creativity, and complexity; in order to improve the efficiency and quality of product scheme design, it has important research value to reasonably organize, reason, and reuse design knowledge. In this paper, the extension modeling problem under the extension design mode of complex product scheme is studied, the multitype design knowledge element modeling expression model of complex product scheme design is given, and the extension process model and the implication process model of requirement analysis of complex product scheme design is established. A new demand element weight assignment method based on extension distance is proposed to obtain accurate demand analysis index weight from the perspective of combined qualitative and quantitative analysis. On the basis of constructing the extension correlation degree of demand primitives, this paper puts forward the implementation method of the extension design pattern for the demand analysis of a complex product scheme design and gives the specific implementation algorithm. Finally, an example of product design is given to illustrate the method, and the results show the effectiveness and operability of the method.
Fractional Q-Switched 1064 nm Laser for Treatment of Atrophic Scars in Asian Skin
Authors: Nisticò Steven Paul , Sannino Mario , Fasano Gaia , Marigliano Miriam , Negosanti Francesca , Bennardo Luigi , Cannarozzo Giovanni
Published: September 2022

Background and Objectives: Asian patients with Fitzpatrick skin type III–IV are a less studied subtype of patients in the medical literature. Q-Switched, 1064 nm neodymium-doped yttrium aluminum garnet (Nd: YAG) laser with a fractionated beam profile (QSF) is a new modality that was reported to be effective in the treatment of scars. This study aims to evaluate the efficacy and safety of QSF Nd: YAG laser in treating scars in Asian patients. Materials and Methods: A total of 29 Subjects were treated with 1064 nm QSF laser. Each patients had three treatments with a fractionated microlens array handpiece every 8 weeks). Efficacy of treatment was evaluated using the Goodman and Baron’s quantitative grading scale before and 3 months after the last treatment. Results: All 29 patients treated had significant improvement of acne scars according to Goodman and Baron’s Quantitative Global Acne Scarring Grading System. No side effect has been observed except some minor erythematous reactions in three patients. Conclusions: Our results confirm that the 1064 nm QSF Nd: YAG laser is a safe and effective technique for treating scars in Asians.
Modification of Thin Film Composite Membrane by Chitosan–Silver Particles to Improve Desalination and Anti-Biofouling Performance
Authors: Armendáriz-Ontiveros María Magdalena , Villegas-Peralta Yedidia , Madueño-Moreno Julia Elizabeth , Álvarez-Sánchez Jesús , Dévora-Isiordia German Eduardo , Sánchez-Duarte Reyna G. , Madera-Santana Tomás Jesús
Published: September 2022

Reverse osmosis (RO) desalination is a technology that is commonly used to mitigate water scarcity problems; one of its disadvantages is the bio-fouling of the membranes used, which reduces its performance. In order to minimize this problem, this study prepared modified thin film composite (TFC) membranes by the incorporation of chitosan–silver particles (CS–Ag) of different molecular weights, and evaluated them in terms of their anti-biofouling and desalination performances. The CS–Ag were obtained using ionotropic gelation, and were characterized by Fourier transform infrared spectroscopy (FTIR), high-resolution scanning electron microscopy (HR-SEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA) and dynamic light scattering (DLS). The modified membranes were synthetized by the incorporation of the CS–Ag using the interfacial polymerization method. The membranes (MCS–Ag) were characterized by Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and contact angle. Bactericidal tests by total cell count were performed using Bacillus halotolerans MCC1, and anti-adhesion properties were confirmed through biofilm cake layer thickness and total organic carbon (%). The desalination performance was defined by permeate flux, hydraulic resistance, salt rejection and salt permeance by using 2000 and 5000 mg L−1 of NaCl. The MCS–Ag-L presented superior permeate flux and salt rejection (63.3% and 1% higher, respectively), as well as higher bactericidal properties (76% less in total cell count) and anti-adhesion capacity (biofilm thickness layer 60% and total organic carbon 75% less, compared with the unmodified membrane). The highest hydraulic resistance value was for MCS–Ag-M. In conclusion, the molecular weight of CS–Ag significantly influences the desalination and the antimicrobial performances of the membranes; as the molecular weight decreases, the membranes’ performances increase. This study shows a possible alternative for increasing membrane useful life in the desalination process.
Investigation of Scaling and Inhibition Mechanisms in Reverse Osmosis Spiral Wound Elements
Authors: Pervov Alexei
Published: September 2022

Understanding of crystal formation and growth conditions in reverse osmosis membrane channels enables us to develop efficient tools to control scaling in membrane facilities and increase their recoveries. Crystals are formed in “dead areas” and subsequently get out of them and sediment on membrane surface. Adsorption of polymeric inhibitor molecules to crystal surface was investigated as well as antiscalant behaviour throughout nucleation in “dead areas” and growth of crystals sedimented on membrane surface. Experimental dependencies of antiscalant adsorption rates on the antiscalant dosage values were determined. Examination of SEM images of crystals demonstrated that their size and amount depend on the supersaturation value reached in the “dead areas”. More efficient antiscalants delay the beginning of nucleation and reduce the rate of crystal growth due to adsorption and blockage of crystal growth process. Antiscaling property of inhibitors is also attributed to their ability to provide certain amount of adsorbent to block crystal growth during nucleation. A test procedure is described that enables us to predict concentrate composition in the “dead areas” and calculate supersaturation values that correspond to beginning of nucleation.
Antifungal Activity, Structural Stability, and Immunomodulatory Effects on Human Immune Cells of Defensin from the Lentil Lens culinaris
Authors: Finkina Ekaterina I. , Bogdanov Ivan V. , Ignatova Anastasia A. , Kanushkina Marina D. , Egorova Ekaterina A. , Voropaev Alexander D. , Stukacheva Elena A. , Ovchinnikova Tatiana V.
Published: September 2022

An increase in the frequency of mycoses and spreading of multidrug-resistant fungal pathogens necessitates the search for new antifungal agents. Earlier, we isolated the novel defensin from lentil Lensculinaris seeds, designated as Lc-def, which inhibited the growth of phytopathogenic fungi. Here, we studied an antifungal activity of Lc-def against human pathogenic Candida species, structural stability of the defensin, and its immunomodulatory effects that may help to prevent fungal infection. We showed that Lc-def caused 50% growth inhibition of clinical isolates of Candida albicans, C. krusei, and C. glabrata at concentrations of 25–50 μM, but was not toxic to different human cells. The lentil defensin was resistant to proteolysis by C. albicans and was not cleaved during simulated gastroduodenal digestion. By using the multiplex xMAP assay, we showed for the first time for plant defensins that Lc-def increased the production of such essential for immunity to candidiasis pro-inflammatory cytokines as IL-12 and IL-17 at the concentration of 2 μM. Thus, we hypothesized that the lentil Lc-def and plant defensins in general may be effective in suppressing of mucocutaneous candidiasis due to their antifungal activity, high structural stability, and ability to activate a protective immune response.
The Transport Properties of Semi-Crystalline Polyetherimide BPDA-P3 in Amorphous and Ordered States: Computer Simulations
Authors: Dobrovskiy Alexey , Nazarychev Victor , Volgin Igor , Lyulin Sergey
Published: September 2022

The effect of polymer chain ordering on the transport properties of the polymer membrane was examined for the semi-crystalline heterocyclic polyetherimide (PEI) BPDA-P3 based on 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and diamine 1,4-bis [4-(4-aminophenoxy)phenoxy]benzene (P3). All-atom Molecular Dynamics (MD) simulations were used to investigate the gas diffusion process carried out through the pores of a free volume several nanometers in size. The long-term (~30 μs) MD simulations of BPDA-P3 were performed at T = 600 K, close to the experimental value of the melting temperature (Tm ≈ 577 K). It was found during the simulations that the transition of the PEI from an amorphous state to an ordered one occurred. We determined a decrease in solubility for both gases examined (CO2 and CH4), caused by the redistribution of free volume elements occurring during the structural ordering of the polymer chains in the glassy state (Tg ≈ 487 K). By analyzing the diffusion coefficients in the ordered state, the presence of gas diffusion anisotropy was found. However, the averaged values of the diffusion coefficients did not differ from each other in the amorphous and ordered states. Thus, permeability in the observed system is primarily determined by gas solubility, rather than by gas diffusion.
Machining Distortion for Thin-Walled Superalloy GH4169 Caused by Residual Stress and Manufacturing Sequences
Authors: Zhu Pingzhong , Liu Zhanqiang , Ren Xiaoping , Cai Yukui
Published: September 2022

The residual stress generated in the machining process has a passive influence on the machining accuracy of a thin-walled workpiece. Annealing treatment can release the residual stress induced in the machining process and suppress the machining distortion. However, there is no unified standard for whether annealing treatment is arranged after machining. In this paper, an analytical model for predicting the distortion caused by residual stress of thin-walled superalloy GH4169 is established. Then, the finite element method is applied to analyze the prediction results of the proposed model. It is found that the residual stress generated in the manufacturing process chain can cause large distortion for the thin-walled workpiece. Finally, combined with the law and principle of workpiece distortion, the annealing process planning of multiple manufacturing sequences of thin-walled superalloy GH4169 is formulated to suppress the machining distortion. For the machining process on one side of the workpiece, it is necessary to release residual stress. This is not necessary for the double-sided machining process. Research results can be used to optimize the manufacturing sequence of thin-walled components.
Assessing the Sensitivity of Multi-Distance Hyperspectral NIRS to Changes in the Oxidation State of Cytochrome C Oxidase in the Brain
Authors: Suwalski Marianne , Shoemaker Leena N. , Shoemaker J. Kevin , Diop Mamadou , Murkin John M. , Chui Jason , St. Lawrence Keith , Milej Daniel
Published: September 2022

Near-infrared spectroscopy (NIRS) measurements of tissue oxygen saturation (StO2) are frequently used during vascular and cardiac surgeries as a non-invasive means of assessing brain health; however, signal contamination from extracerebral tissues remains a concern. As an alternative, hyperspectral (hs)NIRS can be used to measure changes in the oxidation state of cytochrome c oxidase (ΔoxCCO), which provides greater sensitivity to the brain given its higher mitochondrial concentration versus the scalp. The purpose of this study was to evaluate the depth sensitivity of the oxCCO signal to changes occurring in the brain and extracerebral tissue components. The oxCCO assessment was conducted using multi-distance hsNIRS (source-detector separations = 1 and 3 cm), and metabolic changes were compared to changes in StO2. Ten participants were monitored using an in-house system combining hsNIRS and diffuse correlation spectroscopy (DCS). Data were acquired during carotid compression (CC) to reduce blood flow and hypercapnia to increase flow. Reducing blood flow by CC resulted in a significant decrease in oxCCO measured at rSD = 3 cm but not at 1 cm. In contrast, significant changes in StO2 were found at both distances. Hypercapnia caused significant increases in StO2 and oxCCO at rSD = 3 cm, but not at 1 cm. Extracerebral contamination resulted in elevated StO2 but not oxCCO after hypercapnia, which was significantly reduced by applying regression analysis. This study demonstrated that oxCCO was less sensitive to extracerebral signals than StO2.
Iron Metabolism in the Disorders of Heme Biosynthesis
Authors: Ricci Andrea , Di Betto Giada , Bergamini Elisa , Buzzetti Elena , Corradini Elena , Ventura Paolo
Published: September 2022

Given its remarkable property to easily switch between different oxidative states, iron is essential in countless cellular functions which involve redox reactions. At the same time, uncontrolled interactions between iron and its surrounding milieu may be damaging to cells and tissues. Heme—the iron-chelated form of protoporphyrin IX—is a macrocyclic tetrapyrrole and a coordination complex for diatomic gases, accurately engineered by evolution to exploit the catalytic, oxygen-binding, and oxidoreductive properties of iron while minimizing its damaging effects on tissues. The majority of the body production of heme is ultimately incorporated into hemoglobin within mature erythrocytes; thus, regulation of heme biosynthesis by iron is central in erythropoiesis. Additionally, heme is a cofactor in several metabolic pathways, which can be modulated by iron-dependent signals as well. Impairment in some steps of the pathway of heme biosynthesis is the main pathogenetic mechanism of two groups of diseases collectively known as porphyrias and congenital sideroblastic anemias. In porphyrias, according to the specific enzyme involved, heme precursors accumulate up to the enzyme stop in disease-specific patterns and organs. Therefore, different porphyrias manifest themselves under strikingly different clinical pictures. In congenital sideroblastic anemias, instead, an altered utilization of mitochondrial iron by erythroid precursors leads to mitochondrial iron overload and an accumulation of ring sideroblasts in the bone marrow. In line with the complexity of the processes involved, the role of iron in these conditions is then multifarious. This review aims to summarise the most important lines of evidence concerning the interplay between iron and heme metabolism, as well as the clinical and experimental aspects of the role of iron in inherited conditions of altered heme biosynthesis.
An Upper Ocean Thermal Field Metrics Dataset
Authors: Sampson Charles R. , Cummings James , Knaff John A. , DeMaria Mark , Serra Efren A.
Published: September 2022

The upper ocean provides a source of thermal energy for tropical cyclone development and maintenance through a series of complex interactions. In this work, we develop a seventeen-year dataset of upper ocean thermal field metrics for use in tropical cyclone studies and development of tropical cyclone intensity prediction models. These metrics include the surface temperature, two different measures of vertically integrated heat content, and four different measures of vertically averaged temperature. Some metrics have been used to study upper-ocean energy response to tropical cyclone passage, while others have been employed to improve operational tropical cyclone intensity prediction models. The vertically integrated ocean heat content has been used to improve tropical cyclone intensity forecasts at U.S. tropical cyclone forecast centers and is an integral part of several operational intensity forecast models. A static 2005–2021 dataset that includes all twelve metrics described within is available on the Naval Research Laboratory web server, and a subset of six metrics have been produced in real-time at Fleet Numerical Meteorology and Oceanography Center and provided to the public via the GODAE server since 2021.
Critical Salt Loading in Flexible Poly(vinyl alcohol) Sensors Fabricated by an Inkjet Printing and Plasma Reduction Method
Authors: Chou Evan , Sui Yongkun , Chong Hao , Brancel Christina , Lewandowski John J. , Zorman Christian A. , Wnek Gary E.
Published: September 2022

We report a low-temperature inkjet printing and plasma treatment method using silver nitrate ink that allows the fabrication of conductive silver traces on poly(vinyl alcohol) (PVA) film with good fidelity and without degrading the polymer substrate. In doing so, we also identify a critical salt loading in the film that is necessary to prevent the polymer from reacting with the silver nitrate-based ink, which improves the resolution of the silver trace while simultaneously lowering its sheet resistance. Silver lines printed on PVA film using this method have sheet resistances of around 0.2 Ω/□ under wet/dry and stretched/unstretched conditions, while PVA films without prior treatment double in sheet resistance upon wetting or stretching the substrate. This low resistance of printed lines on salt-treated films can be preserved under multiple bending cycles of 0–90° and stretching cycles of 0–6% strain if the polymer is prestretched prior to inkjet printing.
Effects of Side Profile on Acoustic Streaming by Oscillating Microstructures in Channel
Authors: Lin Lin , Dang Haojie , Zhu Rongxin , Liu Ying , You Hui
Published: September 2022

In microchannels, microstructure-induced acoustic streaming can be achieved at low frequencies, providing simple platforms for biomedicine and microfluidic manipulation. Nowadays, microstructures are generally fabricated by photolithography or soft photolithography. Existing studies mainly focused on the projection plane, while ignoring the side profile including microstructure’s sidewall and channel’s upper wall. Based on the perturbation theory, the article focuses on the effect of microstructure’s sidewall errors caused by machining and the viscous dissipation of upper wall on the streaming. We discovered that the side profile parameters, particularly the gap (gap g between the top of the structure and the upper wall of the channel), have a significant impact on the maximum velocity, mode, and effective area of the streaming.To broaden the applicability, we investigated boundary layer thickness parameters including frequency and viscosity. Under different thickness parameters, the effects of side profile parameters on the streaming are similar. But the maximum streaming velocity is proportional to the frequency squared and inversely proportional to the viscosity. Besides, the ratio factor θ of the maximum streaming velocity to the vibration velocity is affected by the side profile parameter gap g and sidewall profile angle α.
Quartz Crystal Microbalance-Based Aptasensors for Medical Diagnosis
Authors: Akgönüllü Semra , Özgür Erdoğan , Denizli Adil
Published: September 2022

Aptamers are important materials for the specific determination of different disease-related biomarkers. Several methods have been enhanced to transform selected target molecule-specific aptamer bindings into measurable signals. A number of specific aptamer-based biosensors have been designed for potential applications in clinical diagnostics. Various methods in combination with a wide variety of nano-scale materials have been employed to develop aptamer-based biosensors to further increase sensitivity and detection limit for related target molecules. In this critical review, we highlight the advantages of aptamers as biorecognition elements in biosensors for target biomolecules. In recent years, it has been demonstrated that electrode material plays an important role in obtaining quick, label-free, simple, stable, and sensitive detection in biological analysis using piezoelectric devices. For this reason, we review the recent progress in growth of aptamer-based QCM biosensors for medical diagnoses, including virus, bacteria, cell, protein, and disease biomarker detection.
Prevalence of New and Established Avian Chlamydial Species in Humans and Their Psittacine Pet Birds in Belgium
Authors: De Meyst Anne , Aaziz Rachid , Pex Joachim , Braeckman Lutgart , Livingstone Morag , Longbottom David , Laroucau Karine , Vanrompay Daisy
Published: September 2022

The presence and zoonotic transfer of four different avian Chlamydia spp. was assessed in an epidemiological study in a psittacine bird population and its owners. Fecal swabs from 84 pet birds and pharyngeal swabs from 22 bird owners were collected from 21 locations in Flanders. Samples were examined using established and novel PCR platforms combined with culture on PCR-positive samples. Chlamydiaceae DNA was detected in 33 of 84 (39.3%) birds. The predominant part of the avian infections could be attributed to C. psittaci (22 of 84; 26.2%), followed by C. avium (11 of 84; 13.1%). C. gallinacea and C. abortus were not detected in birds or humans. C. psittaci was the only species detected in pet bird owners (4 of 22; 18.2%), stressing its zoonotic importance. This study showed that C. psittaci and the more recently discovered novel avian species C. avium are undoubtedly present in the Flemish psittacine bird population. Our results justify additional research in a larger psittacine bird population and its owners, focusing on C. psittaci and C. avium. In the meantime, increased awareness among pet bird owners and the implementation of preventive measures in the pet bird industry is advised to limit the circulation of established and novel emerging avian chlamydial species.
Diversity of Culturable Alkaliphilic Nitrogen-Fixing Bacteria from a Soda Lake in the East African Rift Valley
Authors: Ali Yordanos , Simachew Addis , Gessesse Amare
Published: September 2022

Lake Chitu is a highly productive soda lake found in the East African Rift Valley, where Arthrospira fusiformis (Spirulina platensis) is the main primary producer. High biomass accumulation requires an adequate supply of nitrogen. However, Lake Chitu is a closed system without any external nutrient input. A recent study has also demonstrated the presence of a diverse group of denitrifying bacteria, indicating a possible loss of nitrate released from the oxidation of organic matter. The aim of this study was to isolate culturable nitrogen-fixing alkaliphiles and evaluate their potential contribution in the nitrogen economy of the soda lake. A total of 118 alkaliphiles belonging to nine different operational taxonomic units (OTUs) were isolated using a nitrogen-free medium. Nineteen isolates were tested for the presence of the nifH gene, and 11 were positive. The ability to fix nitrogen was tested by co-culturing with a non-nitrogen-fixing alkaliphile, Alkalibacterium sp. 3.5*R1. When inoculated alone, Alkalibacterium sp. 3.5*R1 failed to grow on a nitrogen-free medium, but grew very well when co-cultured with the nitrogen-fixing alkaliphile NF10m6 isolated in this study, indicating the availability of nitrogen. These results show that nitrogen fixation by alkaliphiles may have an important contribution as a source of nitrogen in soda lakes.
Land-Use Change and Management Intensification Is Associated with Shifts in Composition of Soil Microbial Communities and Their Functional Diversity in Coffee Agroecosystems
Authors: Carrasco-Espinosa Karen , Avitia Morena , Barrón-Sandoval Alberto , Abbruzzini Thalita F. , Salazar Cabrera Ulises Isaac , Arroyo-Lambaer Denise , Uscanga Adriana , Campo Julio , Benítez Mariana , Wegier Ana , Rosell Julieta A. , Reverchon Frédérique , Hernández Gerardo , Boege Karina , Escalante Ana E.
Published: September 2022

Despite the central role of microorganisms in soil fertility, little understanding exists regarding the impact of management practices and soil microbial diversity on soil processes. Strong correlations among soil microbial composition, management practices, and microbially mediated processes have been previously shown. However, limited integration of the different parameters has hindered our understanding of agroecosystem functioning. Multivariate analyses of these systems allow simultaneous evaluation of the parameters and can lead to hypotheses on the microbial groups involved in specific nutrient transformations. In the present study, using a multivariate approach, we investigated the effect of microbial composition (16SrDNA sequencing) and soil properties in carbon mineralization (CMIN) (BIOLOG™, Hayward, CA, USA) across different management categories on coffee agroecosystems in Mexico. Results showed that (i) changes in soil physicochemical variables were related to management, not to region, (ii) microbial composition was associated with changes in management intensity, (iii) specific bacterial groups were associated with different management categories, and (iv) there was a broader utilization range of carbon sources in non-managed plots. The identification of specific bacterial groups, management practices, and soil parameters, and their correlation with the utilization range of carbon sources, presents the possibility to experimentally test hypotheses on the interplay of all these components and further our understanding of agroecosystem functioning and sustainable management.
Revealing a New Family of D-2-Hydroxyglutarate Dehydrogenases in Escherichia coli and Pantoea ananatis Encoded by ydiJ
Authors: Samsonov Victor V. , Kuznetsova Anna A. , Rostova Julia G. , Samsonova Svetlana A. , Ziyatdinov Mikhail K. , Kiriukhin Michael Y.
Published: September 2022

In E. coli and P. ananatis, L-serine biosynthesis is initiated by the action of D-3-phosphoglycerate dehydrogenase (SerA), which converts D-3-phosphoglycerate into 3-phosphohydroxypyruvate. SerA can concomitantly catalyze the production of D-2-hydroxyglutarate (D-2-HGA) from 2-ketoglutarate by oxidizing NADH to NAD+. Several bacterial D-2-hydroxyglutarate dehydrogenases (D2HGDHs) have recently been identified, which convert D-2-HGA back to 2-ketoglutarate. However, knowledge about the enzymes that can metabolize D-2-HGA is lacking in bacteria belonging to the Enterobacteriaceae family. We found that ydiJ encodes novel D2HGDHs in P. ananatis and E. coli, which were assigned as D2HGDHPa and D2HGDHEc, respectively. Inactivation of ydiJ in P. ananatis and E. coli led to the significant accumulation of D-2-HGA. Recombinant D2HGDHEc and D2HGDHPa were purified to homogeneity and characterized. D2HGDHEc and D2HGDHPa are homotetrameric with a subunit molecular mass of 110 kDa. The pH optimum was 7.5 for D2HGDHPa and 8.0 for D2HGDHEc. The Km for D-2-HGA was 208 μM for D2HGDHPa and 83 μM for D2HGDHEc. The enzymes have strict substrate specificity towards D-2-HGA and displayed maximal activity at 45 °C. Their activity was completely inhibited by 0.5 mM Mn2+, Ni2+ or Co2+. The discovery of a novel family of D2HGDHs may provide fundamental information for the metabolic engineering of microbial chassis with desired properties.
Comparative Study of Different Diagnostic Routine Methods for the Identification of Acinetobacter radioresistens
Authors: Bigge Richard , Bunk Boyke , Rudolph Wolfram W. , Gunzer Florian , Coldewey Sina M. , Riedel Thomas , Schröttner Percy
Published: September 2022

Recent publications indicate that A. radioresistens can cause infections in humans, even though it is rarely reported in routine diagnostics. However, the fact that it is infrequently detected may be explained by the misidentification of the species by conventional methods. It is also likely that A. radioresistens is not considered clinically relevant and therefore not consistently included in diagnostic results. To elucidate the medical significance of this probably clinically underestimated bacterial species, we created a well-documented reference strain collection of 21 strains collected in routine diagnostics. For further analysis of A. radioresistens, it is essential to know which methods can be used to achieve a trustworthy identification. We, therefore, compared three methods widely used in routine diagnostics (MALDI-TOF MS, VITEK 2, and sequencing of housekeeping genes) in terms of secure and reliable identification of A. radioresistens. As reference methods, whole genome-based approaches were applied. VITEK 2 led to misidentification for four strains. However, MALDI-TOF MS and sequencing of housekeeping genes led to reliable and robust identifications.
Hydro-Volcanism in the Longgang Volcanic Field, Northeast China: Insights from Topography, Stratigraphy, Granulometry and Microtexture of Xidadianzi Maar Volcano
Authors: Zhao Bo , Xu Debing , Bai Zhida , Chen Zhengquan
Published: September 2022

Hydro-volcanism in the Longgang volcanic field (LVF) of Northeast China has produced a dozen maars with features of complex sequences. To better understand the formation mechanism of maar volcanos in the LVF, this study focuses on the Xidadianzi (XDDZ) maar volcano, located in the Jinchuan valley of the LVF. Based on detailed stratigraphy analysis, 14C geochronology, grain-size distribution, and scanning electron microscopy (SEM) analysis, the eruptive sequence of the XDDZ volcano, including the South Crater and the North Crater, was constructed. The whole sequence was formed after four eruptive phases, including a wet phreatomagmatic eruption, an explosive magmatic eruption, a dry and hot phreatomagmatic eruption, and a small explosive magmatic eruption. 14C geochronology indicates that the formation age of XDDZ is 15,900 ± 70 years, BP. Topographic and stratigraphic characteristics show that the landforms of two craters were damaged and buried because of the destruction of lava flows and agricultural modification. The NE- trending fissure in the hard rock area is thought to participate in the formation of the XDDZ maar volcano.
Controllable Phase Transformation and Enhanced Photocatalytic Performance of Nano-TiO2 by Using Oxalic Acid
Authors: Chen Jiaqi , Gao Jian , Liu Xiaoyang , Wang Pan , Yu Xue , Zhao Feng , Sun Yan , Feng Wei , Wang Qingyuan
Published: September 2022

Degradation of organic pollutants, especially organic dyes and antibiotics, by semiconductor photocatalysts is an efficient strategy for wastewater treatment. TiO2 nanomaterials are considered to be promising photocatalysts due to their high chemical stability, high efficiency and availability. Anatase TiO2 generally has superior photocatalytic activity to the rutile phase. However, the anatase phase can be irreversibly transformed to rutile phase when calcined at an elevated temperature. Methods to improve the stability of anatase are especially important for the TiO2 gas sensors working at high temperatures. The addition of strong acids can effectively suppress this transformation process. However, these strong acids are relatively expensive, corrosive and environmentally unfriendly. Herein, oxalic acid (OA) as a natural acid was used to control the hydrolysis process of tetrabutyl titanate (TBOT), leading to controllable crystalline phase transformation and reduced crystalline size of TiO2 on the nanoscale. What is more, the photocatalytic degradation performances were enhanced continuously when the molar ratio of OA to TBOT increased. The degradation reaction rate constants of CT650-R25 were about 10 times that of CT650-R0. The mechanism study shows that the enhanced photocatalytic activity can be attributed to the improved dispersibility, increased specific surface area and reduced recombination rates of photo-induced charge carriers and decreased energy bands as the concentration of OA increased. Thus, this work provides a simple, mild and effective method for controlling the crystalline forms of nano-TiO2 with enhanced photocatalytic performance towards waste water treatment.
Excitation-Dependent Photoluminescence of BaZrO3:Eu3+ Crystals
Authors: Gupta Santosh K. , Abdou Hisham , Segre Carlo U. , Mao Yuanbing
Published: September 2022

The elucidation of local structure, excitation-dependent spectroscopy, and defect engineering in lanthanide ion-doped phosphors was a focal point of research. In this work, we have studied Eu3+-doped BaZrO3 (BZOE) submicron crystals that were synthesized by a molten salt method. The BZOE crystals show orange–red emission tunability under the host and dopant excitations at 279 nm and 395 nm, respectively, and the difference is determined in terms of the asymmetry ratio, Stark splitting, and intensity of the uncommon 5D0 → 7F0 transition. These distinct spectral features remain unaltered under different excitations for the BZOE crystals with Eu3+ concentrations of 0–10.0%. The 2.0% Eu3+-doped BZOE crystals display the best optical performance in terms of excitation/emission intensity, lifetime, and quantum yield. The X-ray absorption near the edge structure spectral data suggest europium, barium, and zirconium ions to be stabilized in +3, +2, and +4 oxidation states, respectively. The extended X-ray absorption fine structure spectral analysis confirms that, below 2.0% doping, the Eu3+ ions occupy the six-coordinated Zr4+ sites. This work gives complete information about the BZOE phosphor in terms of the dopant oxidation state, the local structure, the excitation-dependent photoluminescence (PL), the concentration-dependent PL, and the origin of PL. Such a complete photophysical analysis opens up a new pathway in perovskite research in the area of phosphors and scintillators with tunable properties.
Graphene Film Growth on Silicon Carbide by Hot Filament Chemical Vapor Deposition
Authors: Rodríguez-Villanueva Sandra , Mendoza Frank , Weiner Brad R. , Morell Gerardo
Published: September 2022

The electrical properties of graphene on dielectric substrates, such as silicon carbide (SiC), have received much attention due to their interesting applications. This work presents a method to grow graphene on a 6H-SiC substrate at a pressure of 35 Torr by using the hot filament chemical vapor deposition (HFCVD) technique. The graphene deposition was conducted in an atmosphere of methane and hydrogen at a temperature of 950 °C. The graphene films were analyzed using Raman spectroscopy, scanning electron microscopy, atomic force microscopy, energy dispersive X-ray, and X-ray photoelectron spectroscopy. Raman mapping and AFM measurements indicated that few-layer and multilayer graphene were deposited from the external carbon source depending on the growth parameter conditions. The compositional analysis confirmed the presence of graphene deposition on SiC substrates and the absence of any metal involved in the growth process.
The Response of the Human Umbilical Vein Endothelial Cell Transcriptome to Variation in Magnesium Concentration
Authors: Almousa Lujain A. , Salter Andrew M. , Castellanos Marcos , May Sean T. , Langley-Evans Simon C.
Published: September 2022

Vascular endothelial cells have a critical role in the maintenance of cardiovascular function. Evidence suggests that endothelial function may be compromised under conditions of magnesium deficiency, which increases vulnerability to inflammation. Whole genome transcription analysis was used to explore the acute (24 h) effects of magnesium on human umbilical vascular endothelial cells (HUVEC) cultured in low (0.1 mM) or high (5 mM) concentrations. With low magnesium 2728 transcripts were differentially expressed compared to the 1 mM control cultures and 3030 were differentially expressed with high magnesium. 615 transcripts were differentially expressed under both conditions, of which only 34 showed a concentration-dependent response. Analysis indicated that cellular organisation and biogenesis and key cellular processes such as apoptosis were impacted by both low and high conditions. High magnesium also influenced protein binding functions, intracellular signal transduction, metabolic and catalytic processes. Both conditions impacted on stress-related processes, in particular the inflammatory response. Key mediators of calcium-dependent regulation of gene expression were responsive to both high and low magnesium conditions. The HUVEC transcriptome is highly sensitive to acute changes in the concentration of magnesium in culture medium. The findings of this study support the view that whilst inflammation is an important process that is responsive to magnesium, the function of the endothelium may be impacted by other magnesium-induced changes including maintenance of cellular integrity, receptor expression and metabolic functions. The high proportion of transcripts that did not show a concentration-dependent response suggests variation in magnesium may elicit indirect changes, possibly mediated by other ions.
The Additive Values of the Classification of Higher Serum Uric Acid Levels as a Diagnostic Criteria for Metabolic-Associated Fatty Liver Disease
Authors: He Jie , Ye Junzhao , Sun Yanhong , Feng Shiting , Chen Youpeng , Zhong Bihui
Published: September 2022

Serum uric acid (SUA) is regarded as an independent risk factor for nonalcoholic fatty liver disease (NAFLD). However, the role of SUA in the new diagnosis flowchart of metabolic-associated fatty liver disease (MAFLD) remains unclear. A cross-sectional study enrolled consecutive individuals with ultrasonography and magnetic resonance imaging–based proton density fat fraction (MRI-PDFF) measurements in the First Affiliated Hospital of Sun Yat-sen University from January 2015 to December 2021. All patients were divided into four groups according to their baseline SUA levels and sex. Of the 3537 ultrasound-diagnosed and 1017 MRI-PDFF-diagnosed MAFLD patients included, the prevalence of severe steatosis determined with ultrasound or MRI-PDFF increased across the serum SUA quartiles. The SUA cutoffs were identified as ≥478 µmol/L and ≥423.5 µmol/L for severe steatosis in male and female MAFLD, respectively. Furthermore, using these cutoff values, patients with higher SUA levels in the NAFLD–non-MAFLD group had higher liver fat contents than those without (16.0% vs. 9.7%, p < 0.001). The lean/normal-weight NAFLD–non-MAFLD patients with higher SUA levels are still at high risk of severe steatosis. This study supports the rationale for SUA being established as another risk factor for metabolic dysfunctions in lean/normal-weight MAFLD.