bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiovascular Risk after Kidney Transplantation: Causes and Current Approaches to a Relevant Burden
Authors: Reggiani Francesco , Moroni Gabriella , Ponticelli Claudio
Published: July 2022

Background. Cardiovascular disease is a frequent complication after kidney transplantation and represents the leading cause of mortality in this population. Material and Methods. We searched for the relevant articles in the National Institutes of Health library of medicine, transplant, cardiologic and nephrological journals. Results. The pathogenesis of cardiovascular disease in kidney transplant is multifactorial. Apart from non-modifiable risk factors, such as age, gender, genetic predisposition and ethnicity, several traditional and non-traditional modifiable risk factors contribute to its development. Traditional factors, such as diabetes, hypertension and dyslipidemia, may be present before and may worsen after transplantation. Immunosuppressants and impaired graft function may strongly influence the exacerbation of these comorbidities. However, in the last years, several studies showed that many other cardiovascular risk factors may be involved in kidney transplantation, including hyperuricemia, inflammation, low klotho and elevated Fibroblast Growth Factor 23 levels, deficient levels of vitamin D, vascular calcifications, anemia and poor physical activity and quality of life. Conclusions. The timely and effective treatment of time-honored and recently discovered modifiable risk factors represent the basis of the prevention of cardiovascular complications in kidney transplantation. Reduction of cardiovascular risk can improve the life expectancy, the quality of life and the allograft function and survival.
The Role of Soil Type in Triggering Shallow Landslides in the Alps (Lombardy, Northern Italy)
Authors: Luino Fabio , De Graff Jerome , Biddoccu Marcella , Faccini Francesco , Freppaz Michele , Roccati Anna , Ungaro Fabrizio , D’Amico Michele , Turconi Laura
Published: July 2022

Shallow landslides due to the soil saturation induced by intense rainfall events are very common in northern Italy, particularly in the Alps and Prealps. They are usually triggered during heavy rainstorms, causing severe damage to property, and sometimes causing casualties. A historical study and analysis of shallow landslides and mud-debris flows triggered by rainfall events in Lombardy was carried out for the period of 1911–2010, over an area of 14,019 km2. In this study, intensity–duration rainfall thresholds have been defined using the frequentist approach, considering some pedological characteristics available in regional soil-related databases, such as the soil region, the textural class, and the dominant soil typological units (STU). The soil-based empirical rainfall thresholds obtained considering the soil regions of the study area were significantly different, with a lower threshold for landslide occurrence in the soil region M1 (Alps), where soils developed over siliceous parent material, with respect to the whole study area and the soil region M2 (Prealps), where soils developed over calcareous bedrocks. Furthermore, by considering textural classes, the curves were differentiated, with coarse-textured soils found more likely to triggerlandslides than fine soils. Finally, considering both texture and main soil groups, given the same rainfall duration, the rainfall amount and intensity needed to initiate a landslide increased in the following order: “coarse-skeletal” Cambisols < Umbrisols < Podzols < “fine” Cambisols. The results of this study highlighted the relevant role of pedological conditioning factors in differentiating the activation of rainfall-induced shallow landslides in a definite region. The information on soils can be used to define more precise rainfall–pedological thresholds than empirical thresholds based solely on meteorological conditions, even when they are locally defined. This knowledge is crucial for forecasting and preventing geo-hydrological processes and in developing better warning strategies to mitigate risks and to reduce socio-economic damage.
Dynamic Evolution and Quantitative Attribution of Soil Erosion Based on Slope Units: A Case Study of a Karst Plateau-Gorge Area in SW China
Authors: Shen Chuhong , Xiong Kangning , Shu Tian
Published: July 2022

Exploring the dynamics of soil erosion and identifying its driving mechanisms is key to understanding soil erosion processes, particularly in karst areas. In this study, the RUSLE model, optimized on the basis of rocky desertification factors, was used to estimate soil erosion in a karst plateau gorge area in SW China. The spatial and temporal dynamics of soil erosion in the region over the past 20 years were analyzed on the basis of slope units, while the relationship between soil erosion and elevation, slope, fractional vegetation cover (FVC), karst rocky desertification (KRD), rainfall, and land use cover/change (LUCC) was identified quantitatively by the geographical detector on the basis of spatial heterogeneity. The results showed that: (1) The no erosion area decreased from 2000 to 2020, with the highest proportion of light to medium erosion and an increasing trend of soil erosion. (2) Soil erosion conversion mainly occurred between no erosion, slight erosion, and light erosion. (3) The hotspots of erosion occurred in high slope–low elevation and high slope–high elevation units, while the coldspots of erosion occurred in low slope–low elevation units. (4) Soil erosion was positively correlated with FVC and slope, and negatively correlated with KRD. (5) The dominant factor of soil erosion changed from KRD-slope to LUCC-slope and finally to elevation-slope, while the q value of rainfall-elevation had the most significant increase throughout the study period. This study will help to advance the goal of sustainable development of soil and water conservation in karst areas.
Heterogeneity-Based Management Restores Diversity and Alters Vegetation Structure without Decreasing Invasive Grasses in Working Mixed-Grass Prairie
Authors: Duquette Cameron , McGranahan Devan Allen , Wanchuk Megan , Hovick Torre , Limb Ryan , Sedivec Kevin
Published: July 2022

Non-native plants can reduce grassland biodiversity, degrade wildlife habitat, and threaten rural livelihoods. Management can be costly, and the successful eradication of undesirable species does not guarantee the restoration of ecosystem service delivery. An alternative to the eradication of invasive species in rangelands is to target the restoration of diversity and heterogeneous plant structure, which have direct links to ecosystem function. In this study, we evaluate patch-burn grazing (PBG) with one and two fires per year and variably stocked rotational grazing in Poa pratensis- and Bromus inermis-invaded grasslands using traditional (cover) and process-based (diversity and vegetation structural heterogeneity) frameworks in central North Dakota, USA. Within 3–4 years of initiating management, we found little evidence of decreased Poa pratensis and Bromus inermis cover compared to continuous grazing (Poa pratensis F3,12 = 0.662, p = 0.59; Bromus inermis F3,12 = 0.13, p = 0.13). However, beta diversity increased over time in all treatments compared to continuous grazing (tPBG1 = 2.71, tPBG2 = 3.45, tRotational = 3.72), and variably stocked rotational treatments had greater increases in spatial heterogeneity in litter depth and vegetation structure than continuously grazed pastures (tvisual obstruction= 2.42, p = 0.03; tlitter depth = 2.59, p = 0.02) over the same time period. Alternative frameworks that promote grassland diversity and heterogeneity support the restoration of ecological services and processes in invaded grasslands.
Analyzing Spatial Location Preference of Urban Activities with Mode-Dependent Accessibility Using Integrated Land Use–Transport Models
Authors: Raza Asif , Safdar Muhammad , Zhong Ming , Hunt John Douglas
Published: July 2022

Accessibility is the ease of reaching opportunities (goods, services, activities, and destinations). Accessibility of desirable locations such as households and commercial locations, is typically scaffolded by land use patterns and transportation infrastructure. It can reflect people’s travel convenience, cities’ viability, sustainability, and mitigate the negative effects on the environment and public safety. Consequently, it is recognized as a fundamental principle in urban sustainable development policies worldwide. In the literature, most of the studies have used a static or partially dynamic approach with a single mode such as a car or public transportation by using conventional models. These “static” models assume that household locations are static and that transportation supply and opportunities for social practice activities are fixed in time and space, which can lead to biased or even misleading assumptions in accessibility models. Therefore, the aim of this study is to evaluate the impact of dynamic spatial accessibility through Mode-Dependent Accessibility (MDA) on the location choice behaviors of urban activities such as households and commercialin the City of Wuhan, China. This study employed the Mode-Dependent Travel Demand Model (M-TDM) to measure the impact of short-term MDA on household and commercial activities for the years 2012 and 2015. Additionally, an integrated spatial economic (ISE) model such as PECAS (Production, Exchange, Consumption, Allocation, System) in order to investigate location preferences of urban activities over space and time. Regarding household and commercial location choice, the ISE modeling results revealed that households and commercial activities are sensitive to MDA, especially using transit. The ISE method predicted that the R2 for household and commercial location choice models was 0.84 to 0.90 for transit-based accessibility, whereas the R2 for logsum-based static models was 0.48 to 0.72. In addition, their findings suggest that highly accessible locations that are well served by auto are more appealing for household and commercial activities. The findings of this study will help urban planners, transportation planners, and policymakers take into account the dynamic nature of short-term MDA when zoning and allocating urban activities and public amenities, instead of using static accessibility.
Characterization of In Vivo Damage on Retrieved Total Shoulder Glenoid Liners
Authors: Cheatwood Eric , Simon Gerard , Crosby Lynn , Goswami Tarun
Published: July 2022

An attempt was made to retrieve glenoid liners from revision surgery to undertake a retrospective study to measure the resulting in vivo damage. Since the glenoid liners are circumferential, the curvature changes at every point in the component, an “assisting arm” was designed to hold the liner firmly, thus allowing accurate microscopic measurements. We characterized the damage in terms of pitting, embedded debris, complete fracture, abrasion, deformation, delamination, burnishing, grooving, and scratching that took place mutually exclusively. This study of 26 liners showed embedded debris was the most underrated damage mode found on the liners, followed by pitting and abrasion, representing 65.2% and 52.2% of the liners, respectively. The prevalence of pitting in over half the samples examined is indicative of free-radical oxidation, resulting in a decrease in physical strength from morphological changes in the microstructure. These may initiate from different pathways, however, they may interact with other processes in which other damage initiates and grows, resulting in higher damage causing premature failure due to wear. A probabilistic approach was developed to generate survival time for these liners and may provide a statistical removal time of the glenoid liners in the future.
Role of Gypsum Content on the Long-Term Performance of Lime-Stabilised Soil
Authors: Ebailila Mansour , Kinuthia John , Oti Jonathan
Published: July 2022

The role of gypsum level on the long-term strength and expansion of soil stabilised with different lime contents is not well understood. This research, therefore, studied the effect of varying gypsum concentrations of 0, 3, 6, and 9 wt% (equivalent to the sulfate contents of 0, 1.4, 2.8, and 4.2%, respectively) on the performance of sulfate soil stabilised with two lime levels (4 and 6 wt%). This was carried out to establish the threshold level of gypsum/lime (G/L) at which the increase in G/L ratio does not affect the performance of lime-stabilised sulfate soil. Both unconfined compressive strength (UCS) and expansion, along with the derivative thermogravimetric (DTG) analysis, were adopted to accomplish the present objective. Accordingly, the result indicated that the strength and expansion were proportional to the lime and sulfate content, of which a G/L ratio of 1.5 was the optimum case scenario for UCS, and at the same time, the worst-case scenario for expansion. This discovery is vital, as it is anticipated to serve as a benchmark for future research related to the design of effective binders for suppressing the sulfate-induced expansion in lime-stabilised gypseous soil.
Glass Fibers Reinforced Concrete: Overview on Mechanical, Durability and Microstructure Analysis
Authors: Ahmad Jawad , González-Lezcano Roberto Alonso , Majdi Ali , Ben Kahla Nabil , Deifalla Ahmed Farouk , El-Shorbagy Mohammed A.
Published: July 2022

Prior studies in the literature show promising results regarding the improvements in strength and durability of concrete upon incorporation of glass fibers into concrete formulations. However, the knowledge regarding glass fiber usage in concrete is scattered. Moreover, this makes it challenging to understand the behavior of glass fiber-reinforced concrete. Therefore, a detailed review is required on glass fiber-reinforced concrete. This paper provides a compressive analysis of glass fiber-reinforced composites. All-important properties of concrete such as flowability, compressive, flexural, tensile strength and modulus of elasticity were presented in this review article. Furthermore, durability aspects such as chloride ion penetration, water absorption, ultrasonic pulse velocity (UPV) and acid resistance were also considered. Finally, the bond strength of the fiber and cement paste was examined via scanning electron microscopy. Results indicate that glass fibers improved concrete’s strength and durability but decreased the concrete’s flowability. Higher glass fiber doses slightly decreased the mechanical performance of concrete due to lack of workability. The typical optimum dose is recommended at 2.0%. However, a higher dose of plasticizer was recommended for a higher dose of glass fiber (beyond 2.0%). The review also identifies research gaps that should be addressed in future studies.
Magnetic and Microwave Properties of Nanocomposites Containing Iron Particles Encapsulated in Carbon
Authors: Rinkevich Anatoly B. , Perov Dmitry V. , Tolmacheva Elena A. , Kuznetsov Evgeny A. , Nemytova Olga V. , Uimin Mikhail A.
Published: July 2022

The magnetic and microwave properties of nanocomposites containing iron particles encapsulated in a carbon shell (Fe@C), as well as carbon nanotubes (CNT), have been experimentally studied. The examination of magnetic properties of composites shows that the materials under study contain a ferromagnetic component. The availability of ferromagnetic ordering for the dielectric matrix-based nanocomposite sample with Fe@C particles has been confirmed by the measurement results of the transmission and the reflection coefficients of the microwaves, since the ferromagnetic resonance has been observed. Furthermore, in the fields less than the field of ferromagnetic resonance, there are the signs of the presence of ferromagnetic antiresonance. The ferromagnetic resonance leads to minima in the transmission and reflection coefficients, whereas the antiresonance, conversely, leads to maxima in the reflection coefficient. The measurement results have been compared with the theoretical calculations of the field dependence of microwave transmission and reflection coefficients.
Addition of Two Substantial Side-Branch Silencers to the Interference Silencer by Incorporating a Zero-Mass Metamaterial
Authors: Sakamoto Shuichi , Shin Juung , Abe Shota , Toda Kentaro
Published: July 2022

Zero-mass metamaterials comprise an orifice and a thin film. The resonance between the film and the air mass of the orifice hole is caused by sound waves, which significantly decreases the transmission loss at a specific frequency. The study novelly incorporates acoustic metamaterials in the delay tube of an interference silencer. In this case, it is determined that an interference silencer and a “side-branch silencer with two different branch pipe lengths” can be realized in a single silencer. At certain frequencies, the acoustic mass of the acoustic metamaterial approaches zero, which results in an interference silencer with the full length of the delay tube applied. At other frequencies, the acoustic metamaterial acts as a rigid wall with high transmission loss, thereby reflecting sound waves at the zero-mass metamaterial location. In this case, it is a side-branch silencer with two different tube lengths, corresponding to the tube lengths from the entrance and exit of the delay tube to the zero-mass metamaterial, respectively. The incorporation of zero-mass metamaterial into an interference-type silencer can introduce the silencing effect of a side-branch silencer with two different branch tube lengths without increasing the volume of the interference-type silencer. Theoretical values were obtained using the transfer matrix. Consequently, the theoretical and experimental values were close, enabling us to predict the transmission loss of the proposed silencer.
Correction: García et al. Service Life and Early Age Durability Enhancement due to Combined Metakaolin and Nanosilica in Mortars for Marine Applications. Materials 2020, 13, 1169
Authors: García Ramiro , Reyes Encarnación , Villanueva Paula , de la Rubia Miguel Ángel , Fernández Jaime , Moragues Amparo
Published: July 2022

The authors would like to make a correction in a recently published paper [...]
COVID-19 Associated Guillain–Barré Syndrome: A Report of Nine New Cases and a Review of the Literature
Authors: Ivan Andreea Paula , Odajiu Irina , Popescu Bogdan Ovidiu , Davidescu Eugenia Irene
Published: July 2022

Background: Guillain–Barré syndrome (GBS)—a rare condition characterized by acute-onset immune-mediated polyneuropathy—has been registered as a neurological manifestation of COVID-19, suggesting a possible link between these two conditions. Methods: We report a case series of patients with COVID-19-related GBS hospitalized in the Neurology Department of Colentina Clinical Hospital, Bucharest, Romania, between March 2020 and March 2021. Several variables were analyzed, such as the mean interval between the onset of COVID-19 symptoms and neurological ones, clinical features, treatment course, and outcome. Further on, we conducted a thorough literature review based on the PubMed and ScienceDirect scientific databases. Results: A total of 9 COVID-19 patients developed symptoms of GBS, out of which in 7, it manifested as an acute inflammatory demyelinating polyneuropathy (AIDP). Five patients presented respiratory failure, 2 requiring mechanical ventilation. All patients received a course of intravenous immunoglobulins, 2 additionally requiring plasma exchange. Upon discharge, all but 1 patient (who had not regained the ability to walk) had a positive outcome, and 1 died during admission. In the literature review, we analyzed the published sources at the time of writing. Conclusions: A link between COVID-19 and GBS might be possible; therefore, increased vigilance is required in the early identification of these cases for prompt diagnosis and treatment. Some notable differences such as an earlier onset of GBS symptoms, higher respiratory dysfunction, and higher mortality rates in COVID-19 patients have been observed between the presentation of GBS in the context of COVID-19 and GBS of other causes.
Improved Artificial Neural Network Training Based on Response Surface Methodology for Membrane Flux Prediction
Authors: Ibrahim Syahira , Abdul Wahab Norhaliza
Published: July 2022

This paper presents an improved artificial neural network (ANN) training using response surface methodology (RSM) optimization for membrane flux prediction. The improved ANN utilizes the design of experiment (DoE) technique to determine the neural network parameters. The technique has the advantage of training performance, with a reduced training time and number of repetitions in achieving good model prediction for the permeate flux of palm oil mill effluent. The conventional training process is performed by the trial-and-error method, which is time consuming. In this work, Levenberg–Marquardt (lm) and gradient descent with momentum (gdm) training functions are used, the feed-forward neural network (FFNN) structure is applied to predict the permeate flux, and airflow and transmembrane pressure are the input variables. The network parameters include the number of neurons, the learning rate, the momentum, the epoch, and the training functions. To realize the effectiveness of the DoE strategy, central composite design is incorporated into neural network methodology to achieve both good model accuracy and improved training performance. The simulation results show an improvement of more than 50% of training performance, with less repetition of the training process for the RSM-based FFNN (FFNN-RSM) compared with the conventional-based FFNN (FFNN-lm and FFNN-gdm). In addition, a good accuracy of the models is achieved, with a smaller generalization error.
Functional Analysis of Gastric Tight Junction Proteins in Xenopus laevis Oocytes
Authors: Stein Laura , Brunner Nora , Amasheh Salah
Published: July 2022

The epithelial barrier is crucial for proper gastrointestinal function, preventing the unwanted passage of solutes and therefore representing a prerequisite for vectorial transport. Claudin-4 and claudin-18.2, two critical tight junction proteins of the gastric epithelium, seal neighboring cells in a physically and mechanically challenging environment. As the Xenopus laevis oocyte allows the functional and molecular analyses of claudin interaction, we have addressed the hypothesis that this interaction is not only dependent on mechanical force but also on pH. We expressed human claudin-4 and claudin-18 in Xenopus oocytes, and analyzed them in a two-cell model approach. Cells were clustered in pairs to form contact areas expressing CLDN18 + CLDN18, CLDN4/18 + CLDN4/18, and compared to controls, respectively. Contact areas in cells incubated in medium at pH 5.5 and 7.4 were quantified by employing transmitted light microscopy. After 24 h at pH 5.5, clustering of CLDN18 + CLDN18 and CLDN4/18 + CLDN4/18-expressing oocytes revealed a contact area reduced by 45% and 32%, compared with controls, respectively. A further approach, high-pressure impulse assay, revealed a stronger tight junction interaction at pH 5.5 in oocyte pairs expressing CLDN18 + CLDN18 or CLDN4/18 + CLDN4/18 indicating a protective role of claudin-18 for tight junction integrity during pH challenge. Thus, our current analysis of gastric tight junction proteins further establishes oocytes as an expression and two-cell screening model for tight junction integrity analysis of organ- and tissue-specific claudins by the characterization of homo- and heterophilic trans-interaction dependent on barrier effectors.
Relation between Mechanical Milling Parameters in Phase Transformation and Oxygen Content in Ti–Nb–Mo Powders for Posterior Sintering
Authors: Gouvea Eber de Santi , Rossi Mariana Correa , Escuder Angel Vicente , Afonso Conrado Ramos Moreira , Borrás Vicente Amigó
Published: July 2022

The influence of open vessels during milling for 12, 24, 40 and 60 h on microstructure homogeneity and oxygen content effect in the β Ti–Nb–Mo system microstructure were studied. The β phase increased with longer milling times and the strain hardening on particles was verified at 60 h when agglomeration was greater and was also noticed after 40 h in the continuous mode. Oxygen content dropped slightly until 40 h and increased after 60 h, a result linked with the observed hardening. For 40 h in the continuous mode, the oxygen content was noted near 12 h, 24 h and 40 h with high hardness values. For the sintered parts, the α phase and oxygen content significantly increased in all samples. Microhardness-sintered samples decreased compared to sample powders due to grain growth during the sintering. Bending strength was higher at 60 h with more oxygen and α phase content. After 40 h in the continuous mode, more suitable mechanical properties were reached because hardness and bending strength were closer to bone tissue, which was associated with strain hardening and a small crystallite size.
In Silico Contact Pressure of Metal-on-Metal Total Hip Implant with Different Materials Subjected to Gait Loading
Authors: Jamari J. , Ammarullah Muhammad Imam , Santoso Gatot , Sugiharto S. , Supriyono Toto , van der Heide Emile
Published: July 2022

The use of material for implant bearing has a vital role in minimizing failures that endanger implant recipients. Evaluation of contact pressure of bearing material can be the basis for material selection and have correlations with wear that contribute to the need of revision operations. The current paper aims to investigate three different metallic materials, namely cobalt chromium molybdenum (CoCrMo), stainless steel 316L (SS 316L), and titanium alloy (Ti6Al4V) for application in metal-on-metal bearing of total hip implant in terms of contact pressure. In silico model based on finite element simulation has been considered to predict contact pressure of metal-on-metal bearings under normal walking conditions. It is found that the use of Ti6Al-4V-on-Ti6Al4V is superior in its ability to reduce contact pressure by more than 35% compared to the other studied metal-on-metal couple bearings.
Thermal Stability of the Precipitates in Dilute Al-Er-Zr/Hf Alloys at Elevated Temperature
Authors: Wu Hao , Zhang Qi , Li Li , Huang Mingdong , Zheng Zhikai , Wen Shengping
Published: July 2022

The temporal evolution of microhardness and Al3(Er,Zr/Hf) precipitates are investigated in Al-Er-Zr/Hf alloys during annealing at 450 °C and 500 °C. The microhardness of the alloys decreases continuously with the prolonged annealing time due to the coarsening of the precipitates. Different weakening amplitudes are observed because of the disparity of the precipitate coarsening rate that is related to the disparity in their intrinsic diffusivities of Er, Zr, and Hf solute atoms in an Al matrix. The addition of Hf element is beneficial to enhancing the coarsening resistance, thus improving the thermal stability of the alloys. Introducing such elements to improve the thermal stability of precipitates can provide a new idea or choice for the development of heat-resistant aluminum alloys.
Metabolic Syndrome, BMI, and Polymorphism of Estrogen Receptor-α in Peri- and Post-Menopausal Polish Women
Authors: Krakowiak Jan , Raczkiewicz Dorota , Humeniuk Ewa , Wdowiak Artur , Wróbel Andrzej , Bojar Iwona
Published: July 2022

The study aimed to investigate the association between the estrogen receptor alpha (ERα) polymorphism and the prevalence of metabolic syndrome (MetS) and obesity, as well as the coexistence of MetS and obesity, in peri- and post-menopausal Polish women. The study group consisted of 202 peri-menopausal and 202 post-menopausal women. ERα polymorphism: Xba I and Pvu II, MetS, BMI, and serum estrogen concentration were analyzed. MetS was found in 29% of the peri-menopausal women and in 21% of the post-menopausal women. BMI did not significantly differ between the peri- and post-menopausal women (≈42% were normal weight, ≈40% were overweight, and ≈18% were obese), (p = 0.82). Serum estrogen concentration in the peri-menopausal women was 91 ± 75 pg/mL, while that in the post-menopausal women was 17 ± 9. pg/mL, on average. Peri-menopausal women with AA and TT genotypes of the ERα polymorphism have a lower risk of obesity and MetS and the co-existence of obesity and MetS, whereas those women with the G or C allele have a higher risk of those health problems.
Calculated Elasticity of Al-Bearing Phase D
Authors: Thompson Elizabeth C. , Campbell Andrew J. , Tsuchiya Jun
Published: July 2022

Using first-principles calculations, this study evaluates the structure, equation of state, and elasticity of three compositions of phase D up to 75 GPa: (1) the magnesium endmember [MgSi2O4(OH)2], (2) the aluminum endmember [Al2SiO4(OH)2], and (3) phase D with 50% Al-substitution [AlMg0.5Si1.5O4(OH)2]. We find that the Mg-endmember undergoes hydrogen-bond symmetrization and that this symmetrization is linked to a 22% increase in the bulk modulus of phase D, in agreement with previous studies. Al2SiO4(OH)2 also undergoes hydrogen-bond symmetrization, but the concomitant increase in bulk modulus is only 13%—a significant departure from the 22% increase of the Mg-endmember. Additionally, Al-endmember phase D is denser (2%–6%), less compressible (6%–25%), and has faster compressional (6%–12%) and shear velocities (12%–15%) relative to its Mg-endmember counterpart. Finally, we investigated the properties of phase D with 50% Al-substitution [AlMg0.5Si1.5O4(OH)2], and found that the hydrogen-bond symmetrization, equation of state parameters, and elastic constants of this tie-line composition cannot be accurately modeled by interpolating the properties of the Mg- and Al-endmembers.
Molecular Dynamics Study on the Effect of SiO2/Al2O3 Mass Ratio on the Structural Properties and Viscosity of Molten Fused Red Mud
Authors: Xu Bo , Cao Yaran , Wang Zhengzheng , Du Peipei , Long Yue
Published: July 2022

In this study, molecular dynamics simulation was used to study the effect of SiO2/Al2O3 mass ratio on the structural properties and viscosity of molten fused red mud. The stability of various T–O bonds in the melt was elucidated by analyzing the bond angle and coordination number; the degree of polymerization, and the stability of the melt were explored by analyzing the number of T–O–T bridging oxygen (BO) and the distribution of QSin and QAln of [SiO4]4− as well as that of QSin and QAln  of [AlO4]5−; the self-diffusion coefficient of each atom was determined by mean square displacement (MSD) analysis; and the trend of the melt viscosity was analyzed according to the relationship between diffusion and viscosity. The results show that as the ratio of SiO2/Al2O3 increases, the viscosity of molten fused red mud first increases, then decreases, and finally increases. This is because Ti4 and Fe3+ combine with O2− to form [TiO6]8− octahedron and [FeO4]5− tetrahedra, which increase the degree of depolymerization of the melt.
Characterization of Respirable Dust Generated from Full Scale Cutting Tests in Limestone with Conical Picks at Three Stages of Wear
Authors: Slouka Syd , Brune Jürgen , Rostami Jamal , Tsai Candace , Sidrow Evan
Published: July 2022

Respirable rock dust poses serious long-term health complications to workers in environments where mechanical rock excavation is utilized. The purpose of this study is to characterize respirable dust generated by cutting limestone with new, partially worn, and fully worn conical pick wears. Characterizing limestone respirable dust can aid in decision making for respirable dust suppression levels and exposures throughout the lifetime of a pick in underground mining and engineering activities. The methods include full scale cutting of a limestone sample in the laboratory with three conical picks at different stages of wear. Dust samples were collected during cutting with various instruments connected to pumps and subsequently analyzed to determine the concentrations, mineralogy, particle shapes, and particle size distributions. The results show that the worn pick generated the highest concentration of dust, all picks generated dust containing quartz, all three picks generated dust particles of similar shapes, and all three picks generated various particle size distributions. In conclusion, a preliminary suite of respirable dust characteristics is available and with further future additional studies, results could be used for the evaluation of possible strategies and methods of dust suppression and exposures during mining, tunneling, or drilling activities.
Experimental Study on the Thermal Conductivity of Compacted SPV200 Bentonite
Authors: Ren Guo-Liang , Chung Chih-Chung , Tsai Chia-En , Cuo Che-Jui , Huang Wei-Hsing
Published: July 2022

This study employed two thermal conductivity measuring techniques, including the needle probe-based transient needle-probe method in accordance with ASTM 5334-14 and the surface probe-based transient plane source method in compliance with ISO 22007-2:2015, to examine the thermal conductivity of compacted SPV200 bentonite. The effects of temperature, water content, and dry density on the thermal behavior of SPV200 bentonite were extensively investigated. The test results indicate: (1) thermal conductivity measured by the two methods agreed well, while the transient plane source method exhibited good efficiency; (2) the thermal conductivity of compacted SPV200 increases with water content, dry density, and temperature; (3) three-dimensional representations of the thermal conductivity of SPV200 bentonite as functions of dry density, water content, and temperature were generated to illustrate a clear relationship among them; (4) two multi-parameter models for predicting thermal conductivity of compacted SPV200 bentonite were proposed, and both showed good fits to the experimental data. The results provide a practical approach to the prediction of thermal properties of compacted bentonite, which can be helpful in the coupled thermo-hydro-mechanical analysis of buffer materials.
A Study on the Direct Esterification of Monoalkylphosphates and Dialkylphosphates; The Conversion of the Latter Species to Trialkylphosphates by Alkylating Esterification
Authors: Ábrányi-Balogh Péter , Harsági Nikoletta , Drahos László , Keglevich György
Published: July 2022

The microwave (MW)-assisted direct esterification of certain P-acids is a green method. Quantum chemical calculations revealed that the activation enthalpy (ΔH#) for the exothermic monoalkylphosphate → dialkylphosphate transformation was on the average 156.6 kJ mol−1, while ΔH# for the dialkylphosphate → trialkylphosphate conversion was somewhat higher, 171.2 kJ mol−1, and the energetics of the elemental steps of this esterification was less favorable. The direct monoesterification may be performed on MW irradiation in the presence of a suitable ionic liquid additive. However, the second step, with the less favorable energetics as a whole, could not be promoted by MWs. Hence, dialkylphosphates had to be converted to triesters by another method that was alkylation. In this way, it was also possible to synthesize triesters with different alkyl groups. Eventually a green, P-chloride free MW-promoted two-step method was elaborated for the synthesis of phosphate triesters.
Syntheses and Applications of 1,2,3-Triazole-Fused Pyrazines and Pyridazines
Authors: Hoffman Gavin R. , Schoffstall Allen M.
Published: July 2022

Pyrazines and pyridazines fused to 1,2,3-triazoles comprise a set of heterocycles obtained through a variety of synthetic routes. Two typical modes of constructing these heterocyclic ring systems are cyclizing a heterocyclic diamine with a nitrite or reacting hydrazine hydrate with dicarbonyl 1,2,3-triazoles. Several unique methods are known, particularly for the synthesis of 1,2,3-triazolo[1,5-a]pyrazines and their benzo-fused quinoxaline and quinoxalinone-containing analogs. Recent applications detail the use of these heterocycles in medicinal chemistry (c-Met inhibition or GABAA modulating activity) as fluorescent probes and as structural units of polymers.
Effect of Different Processing Methods on the Chemical Constituents of Scrophulariae Radix as Revealed by 2D NMR-Based Metabolomics
Authors: Duan Xiaohui , Zhang Mina , Du Huan , Gu Xiu , Bai Caihong , Zhang Liuqiang , Chen Kaixian , Hu Kaifeng , Li Yiming
Published: July 2022

Scrophulariae Radix (SR) is one of the oldest and most frequently used Chinese herbs for oriental medicine in China. Before clinical use, the SR should be processed using different methods after harvest, such as steaming, “sweating”, and traditional fire-drying. In order to investigate the difference in chemical constituents using different processing methods, the two-dimensional (2D) 1H-13C heteronuclear single quantum correlation (1H-13C HSQC)-based metabolomics approach was applied to extensively characterize the difference in the chemical components in the extracts of SR processed using different processing methods. In total, 20 compounds were identified as potential chemical markers that changed significantly with different steaming durations. Seven compounds can be used as potential chemical markers to differentiate processing by sweating, hot-air drying, and steaming for 4 h. These findings could elucidate the change of chemical constituents of the processed SR and provide a guide for the processing. In addition, our protocol may represent a general approach to characterizing chemical compounds of traditional Chinese medicine (TCM) and therefore might be considered as a promising approach to exploring the scientific basis of traditional processing of TCM.
Isolating Fe-O2 Intermediates in Dioxygen Activation by Iron Porphyrin Complexes
Authors: Lu Xiaoyan , Wang Shuang , Qin Jian-Hua
Published: July 2022

Dioxygen (O2) is an environmentally benign and abundant oxidant whose utilization is of great interest in the design of bioinspired synthetic catalytic oxidation systems to reduce energy consumption. However, it is unfortunate that utilization of O2 is a significant challenge because of the thermodynamic stability of O2 in its triplet ground state. Nevertheless, nature is able to overcome the spin state barrier using enzymes, which contain transition metals with unpaired d-electrons facilitating the activation of O2 by metal coordination. This inspires bioinorganic chemists to synthesize biomimetic small-molecule iron porphyrin complexes to carry out the O2 activation, wherein Fe-O2 species have been implicated as the key reactive intermediates. In recent years, a number of Fe-O2 intermediates have been synthesized by activating O2 at iron centers supported on porphyrin ligands. In this review, we focus on a few examples of these advances with emphasis in each case on the particular design of iron porphyrin complexes and particular reaction environments to stabilize and isolate metal-O2 intermediates in dioxygen activation, which will provide clues to elucidate structures of reactive intermediates and mechanistic insights in biological processes.
Bridging the Chemical Profiles and Biological Effects of Spathodea campanulata Extracts: A New Contribution on the Road from Natural Treasure to Pharmacy Shelves
Authors: Świątek Łukasz , Sieniawska Elwira , Sinan Kouadio Ibrahime , Zengin Gokhan , Uba Abdullahi Ibrahim , Bene Kouadio , Maciejewska-Turska Magdalena , Rajtar Barbara , Polz-Dacewicz Małgorzata , Aktumsek Abdurrahman
Published: July 2022

Spathodea campanulata is an important medicinal plant with traditional uses in the tropical zone. In the current work, we aimed to determine the chemical profiles and biological effects of extracts (methanolic and infusion (water)) from the leaves and stem bark of S. campanulata. The chemical components of the tested extracts were identified using LC-ESI-QTOF-MS. Biological effects were tested in terms of antioxidant (radical scavenging, reducing power, and metal chelating), enzyme inhibitory (cholinesterase, amylase, glucosidase, and tyrosinase), antineoplastic, and antiviral activities. Fifty-seven components were identified in the tested extracts, including iridoids, flavonoids, and phenolic acids as the main constituents. In general, the leaves-MeOH extract was the most active in the antioxidant assays (DPPH, ABTS, CUPRAC, FRAP, metal chelating, and phosphomolybdenum). Antineoplastic effects were tested in normal (VERO cell line) and cancer cell lines (FaDu, HeLa, and RKO). The leaf infusion, as well as the extracts obtained from stem bark, showed antineoplastic activity (CC50 119.03–222.07 µg/mL). Antiviral effects were tested against HHV-1 and CVB3, and the leaf methanolic extract (500 µg/mL) exerted antiviral activity towards HHV-1, inhibiting the viral-induced cytopathic effect and reducing the viral infectious titre by 5.11 log and viral load by 1.45 log. In addition, molecular docking was performed to understand the interactions between selected chemical components and viral targets (HSV-1 DNA polymerase, HSV-1 protease, and HSV-1 thymidine kinase). The results presented suggest that S. campanulata may be a bright spot in moving from natural sources to industrial applications, including novel drugs, cosmeceuticals, and nutraceuticals.
First Example of Fluorinated Phenanthroline Diamides: Synthesis, Structural Study, and Complexation with Lanthanoids
Authors: Avagyan Nane A. , Lemport Pavel S. , Lysenko Konstantin A. , Gudovannyy Alexey O. , Roznyatovsky Vitaly A. , Petrov Valentine S. , Vokuev Mikhail F. , Ustynyuk Yuri A. , Nenajdenko Valentine G.
Published: July 2022

An efficient approach to the synthesis of diamides of 4,7-difluoro-1,10-phenanthroline-2,9-dicarboxylic acid was elaborated. Direct nucleophilic substitution with 4,7-dichloro-1,10-phenanthroline precursors opened access to difluoro derivatives in high yield. As a result, four new fluorinated ligands were prepared in up to 88% yield. Their structure was proved by a combination of spectral methods and X-ray data. A set of lanthanoid complexes was prepared to demonstrate the utility of new ligands. The structure of the complexes was studied in solid state (IR-spectroscopy, X-ray diffraction) and in solution (NMR-spectroscopy).
Wetting Properties of Rhamnolipid and Surfactin Mixtures with Triton X-165
Authors: Rekiel Edyta , Zdziennicka Anna , Szymczyk Katarzyna , Jańczuk Bronisław
Published: July 2022

The wetting properties of the rhamnolipid and surfactin mixtures with Triton X-165 were considered based on the contact angle measurements of their aqueous solution on the polytetrafluoroethylene (PTFE), polymethyl methacrylate (PMMA) and quartz (Q) surfaces. The obtained contact angle isotherms were described by the exponential function of the second order as well as by Szyszkowski equation in some cases. Using the contact angle isotherms of individual biosurfactants and TX165 as well as the earlier obtained isotherms of their surface tension the contact angle isotherms of the biosurfactants mixtures with TX165 were deduced. As follows the presence of the maxima on the contact angle isotherms of the biosurfactants mixtures with TX165 is justified. They do not prove negative adsorption of the biosurfactant and TX165 at the interfaces. However, the mutual exchange of the biosurfactant and TX165 molecules is observed in the layers at the interfaces. The concentration of the studied mixtures at the PTFE-solution interface was established to be close to that at the solution-air one but that at the PTFE-air is equal to zero. However, the concentration of the studied mixtures at the PMMA-solution and quartz-solution is greater than zero. The concentration at the PMMA(quartz)-air and PMMA(quartz)-solution interfaces is smaller than that at the solution-air one.
Biological Evaluation, Phytochemical Screening, and Fabrication of Indigofera linifolia Leaves Extract-Loaded Nanoparticles
Authors: Talha Muhammad , Islam Noor Ul , Zahoor Muhammad , Sadiq Abdul , Nawaz Asif , Khan Farhat Ali , Gulfam Naila , Alshamrani Saleh A. , Nahari Mohammed H. , Alshahrani Mohammed Abdulrahman , Mahnashi Mater H. , Hassan Syed Shams ul
Published: July 2022

Indigofera linifolia is a medicinally important plant, and by virtue of its rich phytochemical composition, this plant is widely used as essential component in traditional medication systems. Due to its wide range of medicinal applications, the extract-loaded chitosan (Ext+Ch), extract-loaded PEG (Ext+PEG), and extract-loaded locust bean gum (Ext+LGB) nanoparticles (NPs) were prepared in the present study. The prepared NPs were then evaluated for their antibacterial, antioxidant, and antidiabetic potentials. Antibacterial activities of the crude extract and the synthesized NPs were performed following standard procedures reported in the literature. The antioxidant capabilities of extract and NPs were evaluated using DPPH free radical scavenging assay. The antidiabetic potential of the samples was evaluated against α-amylase and α-glucosidase. Ext+PEG NPs showed more potent antibacterial activity against the selected strains of bacteria with the highest activity against Escherichia coli. The lowest antibacterial potential was observed for Ext+LGB NPs. The Ext+LGB NPs IC50 value of 39 μg/mL was found to be the most potent inhibitor of DPPH free radicals. Ext+LGB NPs showed a greater extent of inhibition against α-glucosidase and α-amylase with an IC50 of 83 and 78 μg/mL, whereas for the standard acarbose the IC50 values recorded against the mentioned enzymes were 69 and 74 μg/mL, respectively. A high concentration of phenolics and flavonoids in the crude extract was confirmed through TPC and TFC tests, HPLC profiling, and GC–MS analysis. It was considered that the observed antibacterial, antidiabetic, and antioxidant potential might be due the presence of these phenolics and flavonoids detected. The plant could thus be considered as a potential candidate to be used as a remedy of the mentioned health complications. However, further research in this regard is needed to isolate the exact responsible compounds of the observed biological potentials exhibited by the crude extract. Further, toxicity and pharmacological evaluations in animal models are also needed to establish the safety or toxicity profile of the plant.
Increasing Value of Winery Residues through Integrated Biorefinery Processes: A Review
Authors: Rodrigues Rafaela P. , Gando-Ferreira Licínio M. , Quina Margarida J.
Published: July 2022

The wine industry is one of the most relevant socio-economic activities in Europe. However, this industry represents a growing problem with negative effects on the environment since it produces large quantities of residues that need appropriate valorization or management. From the perspective of biorefinery and circular economy, the winery residues show high potential to be used for the formulation of new products. Due to the substantial quantities of phenolic compounds, flavonoids, and anthocyanins with high antioxidant potential in their matrix, these residues can be exploited by extracting bioactive compounds before using the remaining biomass for energy purposes or for producing fertilizers. Currently, there is an emphasis on the use of new and greener technologies in order to recover bioactive molecules from solid and liquid winery residues. Once the bio compounds are recovered, the remaining residues can be used for the production of energy through bioprocesses (biogas, bioethanol, bio-oil), thermal processes (pyrolysis, gasification combustion), or biofertilizers (compost), according to the biorefinery concept. This review mainly focuses on the discussion of the feasibility of the application of the biorefinery concept for winery residues. The transition from the lab-scale to the industrial-scale of the different technologies is still lacking and urgent in this sector.