bluuebunny/crossref_metadata_2025 huggingface dataset:
Time-Dependent Effect of Seepage Force on Initiation of Hydraulic Fracture around a Vertical Wellbore
Authors: Rim Hyonchol , Chen Youliang , Tokgo Jun , Du Xi , Li Yi , Wang Suran
Published: March 2023

Fluid penetration into the rock during hydraulic fracturing has been an essential issue in studying the mechanism of fracture initiation, especially the seepage force caused by fluid penetration, which has an important effect on the fracture initiation mechanism around a wellbore. However, in previous studies, the effect of seepage force under unsteady seepage on the fracture initiation mechanism was not considered. In this study, a new seepage model that can predict the variations of pore pressure and seepage force with time around a vertical wellbore for hydraulic fracturing was established by using the method of separation of variables and the Bessel function theory. Then, based on the proposed seepage model, a new circumferential stress calculation model considering the time-dependent effect of seepage force was established. The accuracy and applicability of the seepage model and the mechanical model were verified by comparison with numerical, analytical and experimental results. The time-dependent effect of seepage force on fracture initiation under unsteady seepage was analyzed and discussed. The results show that when the wellbore pressure is constant, the circumferential stress induced by seepage force increases over time, and the possibility of fracture initiation also increases. The higher the hydraulic conductivity, the lower the fluid viscosity and the shorter the time required for tensile failure during hydraulic fracturing. In particular, when the tensile strength of rock is lower, the fracture initiation may occur within the rock mass rather than on the wellbore wall. This study is promising to provide a theoretical basis and practical guidance for further research on fracture initiation in the future.
Intercoupling of Cascaded Metasurfaces for Broadband Spectral Scalability
Authors: Zhou Shaolin , Liu Liang , Deng Qinling , Liao Shaowei , Xue Quan , Chan Mansun
Published: March 2023

Electromagnetic metasurfaces have been intensively used as ultra-compact and easy-to-integrate platforms for versatile wave manipulations from optical to terahertz (THz) and millimeter wave (MMW) ranges. In this paper, the less investigated effects of the interlayer coupling of multiple metasurfaces cascaded in parallel are intensively exploited and leveraged for scalable broadband spectral regulations. The hybridized resonant modes of cascaded metasurfaces with interlayer couplings are well interpreted and simply modeled by the transmission line lumped equivalent circuits, which are used in return to guide the design of the tunable spectral response. In particular, the interlayer gaps and other parameters of double or triple metasurfaces are deliberately leveraged to tune the inter-couplings for as-required spectral properties, i.e., the bandwidth scaling and central frequency shift. As a proof of concept, the scalable broadband transmissive spectra are demonstrated in the millimeter wave (MMW) range by cascading multilayers of metasurfaces sandwiched together in parallel with low-loss dielectrics (Rogers 3003). Finally, both the numerical and experimental results confirm the effectiveness of our cascaded model of multiple metasurfaces for broadband spectral tuning from a narrow band centered at 50 GHz to a broadened range of 40~55 GHz with ideal side steepness, respectively.
Effect of Two-Step Sintering on the Mechanical and Electrical Properties of 5YSZ and 8YSZ Ceramics
Authors: Li Yunpeng , Sun Hongqian , Song Jing , Zhang Zhiyu , Lan Hao , Tian Liangliang , Xie Keqiang
Published: March 2023

Yttria-stabilized zirconia (YSZ) has been widely used in structural and functional ceramics because of its excellent physicochemical properties. In this paper, the density, average gain size, phase structure, and mechanical and electrical properties of conventionally sintered (CS) and two-step sintered (TSS) 5YSZ and 8YSZ are investigated in detail. As the grain size of YSZ ceramics became smaller, dense YSZ materials with a submicron grain size and low sintering temperature were optimized in terms of their mechanical and electrical properties. 5YSZ and 8YSZ in the TSS process significantly improved the plasticity, toughness, and electrical conductivity of the samples and significantly suppressed the rapid grain growth. The experimental results showed that the hardness of the samples was mainly affected by the volume density, that the maximum fracture toughness of 5YSZ increased from 3.514 MPa·m1/2 to 4.034 MPa·m1/2 in the TSS process, an increase of 14.8%, and that the maximum fracture toughness of 8YSZ increased from 1.491 MPa·m1/2 to 2.126 MPa·m1/2, an increase of 42.58%. The maximum total conductivity of the 5YSZ and 8YSZ samples under 680 °C increased from 3.52 × 10−3 S/cm and 6.09 × 10−3 S/cm to 4.52 × 10−3 S/cm and 7.87 × 10−3 S/cm, an increase of 28.41% and 29.22%, respectively.
Viscoelastic Properties of Human Facial Skin and Comparisons with Facial Prosthetic Elastomers
Authors: Beatty Mark W. , Wee Alvin G. , Marx David B. , Ridgway Lauren , Simetich Bobby , De Sousa Thiago Carvalho , Vakilzadian Kevin , Schulte Joel
Published: March 2023

Prosthesis discomfort and a lack of skin-like quality is a source of patient dissatisfaction with facial prostheses. To engineer skin-like replacements, knowledge of the differences between facial skin properties and those for prosthetic materials is essential. This project measured six viscoelastic properties (percent laxity, stiffness, elastic deformation, creep, absorbed energy, and percent elasticity) at six facial locations with a suction device in a human adult population equally stratified for age, sex, and race. The same properties were measured for eight facial prosthetic elastomers currently available for clinical usage. The results showed that the prosthetic materials were 1.8 to 6.4 times higher in stiffness, 2 to 4 times lower in absorbed energy, and 2.75 to 9 times lower in viscous creep than facial skin (p < 0.001). Clustering analyses determined that facial skin properties fell into three groups—those associated with body of ear, cheek, and remaining locations. This provides baseline information for designing future replacements for missing facial tissues.
Advancements in Laser Wire-Feed Metal Additive Manufacturing: A Brief Review
Authors: Abuabiah Mohammad , Mbodj Natago Guilé , Shaqour Bahaa , Herzallah Luqman , Juaidi Adel , Abdallah Ramez , Plapper Peter
Published: March 2023

Laser Wire-Feed Metal Additive Manufacturing (LWAM) is a process that utilizes a laser to heat and melt a metallic alloy wire, which is then precisely positioned on a substrate, or previous layer, to build a three-dimensional metal part. LWAM technology offers several advantages, such as high speed, cost effectiveness, precision control, and the ability to create complex geometries with near-net shape features and improved metallurgical properties. However, the technology is still in its early stages of development, and its integration into the industry is ongoing. To provide a comprehensive understanding of the LWAM technology, this review article emphasizes the importance of key aspects of LWAM, including parametric modeling, monitoring systems, control algorithms, and path-planning approaches. The study aims to identify potential gaps in the existing literature and highlight future research opportunities in the field of LWAM, with the goal of advancing its industrial application.
Effects of Critical Operation and Cleaning Parameters on Performances and Economic Benefits of Biogas Slurry Concentration by Forward Osmosis Membrane
Authors: Zhang Bangxi , Fu Tianhong , Zhang Qinyu , Wang Xiaomin , Tang Ling , Wei Quanquan , Li Yun , Peng Yutao
Published: March 2023

Forward osmosis membrane technology (FO) shows potential application prospects in biogas slurry concentration, which is conducive to promoting the sustainable development of biogas projects. However, at present, the key influencing factors of membrane concentration using FO are not well understood. Therefore, this study analyzed the influence of draw solution concentration, pH, temperature and cross-flow velocity on the concentration efficiency of FO membrane, and optimized the operation parameters of FO membrane. The results showed that the concentration effect of the NaCl draw solution at pH 5 or 9 was better than that at pH 7. The order of factor influencing the water flux was as follows: draw liquid concentration > cross-flow velocity > operating temperature. The optimal combination obtained by orthogonal analysis was under 45 °C, with a cross-flow velocity of 1 L/min and the use of 1.5 mol/L NaCl as draw solution. The results of the membrane cleaning implied that the recovery rate of the fouled membrane after acid–base cleaning is significantly higher (88%) than other cleaning solutions. This research offers a scientific reference for applying positive osmosis technology to re-utilize biogas slurry resources.
Energetic Valorisation of Saltworks Bitterns via Reverse Electrodialysis: A Laboratory Experimental Campaign
Authors: Abdullah Shah Syed , Cucchiara Roberta , Vicari Fabrizio , Cipollina Andrea , Tamburini Alessandro , Micale Giorgio
Published: March 2023

Concentrated bitterns discharged from saltworks have extremely high salinity, often up to 300 g/L, thus their direct disposal not only has a harmful effect on the environment, but also generates a depletion of a potential resource of renewable energy. Here, reverse electrodialysis (RED), an emerging electrochemical membrane process, is proposed to capture and convert the salinity gradient power (SGP) intrinsically conveyed by these bitterns also aiming at the reduction of concentrated salty water disposal. A laboratory-scale RED unit has been adopted to study the SGP potential of such brines, testing ion exchange membranes from different suppliers and under different operating conditions. Membranes supplied by Fujifilm, Fumatech, and Suez were tested, and the results were compared. The unit was fed with synthetic hypersaline solution mimicking the concentration of natural bitterns (5 mol/L of NaCl) on one side, and with variable concentration of NaCl dilute solutions (0.01–0.1 mol/L) on the other. The influence of several operating parameters has also been assessed, including solutions flowrate and temperature. Increasing feed solutions’ temperature and velocity has been found to lower the stack resistance, which enhances the output performance of the RED stack. The maximum obtained power density (corrected to account for the effect of electrodic compartments, which can be very relevant in five cell pairs laboratory stacks) reached around 10.5 W/m2cellpair, with FUJIFILM Type 10 membranes, temperature of 40 °C, and a fluid velocity of 3 cm s−1 (as empty channel, considering 270 μm thickness). Notably, the present study results confirm the large potential for SGP generation from hypersaline brines, thus providing useful guidance for the harvesting of SGP in seawater saltworks all around the world.
Programmable Physical Properties of Freestanding Chitosan Membranes Electrofabricated in Microfluidics
Authors: Ly Khanh L. , Hu Piao , Raub Christopher B. , Luo Xiaolong
Published: March 2023

Microfluidic-integrated freestanding membranes with suitable biocompatibility and tunable physicochemical properties are in high demand for a wide range of life science and biological studies. However, there is a lack of facile and rapid methods to integrate such versatile membranes into microfluidics. A recently invented interfacial electrofabrication of chitosan membranes offers an in-situ membrane integration strategy that is flexible, controllable, simple, and biologically friendly. In this follow-up study, we explored the ability to program the physical properties of these chitosan membranes by varying the electrofabrication conditions (e.g., applied voltage and pH of alginate). We found a strong association between membrane growth rate, properties, and fabrication parameters: high electrical stimuli and pH of alginate resulted in high optical retardance and low permeability, and vice versa. This suggests that the molecular alignment and density of electrofabricated chitosan membranes could be actively tailored according to application needs. Lastly, we demonstrated that this interfacial electrofabrication could easily be expanded to produce chitosan membrane arrays with higher uniformity than the previously well-established flow assembly method. This study demonstrates the tunability of the electrofabricated membranes’ properties and functionality, thus expanding the utility of such membranes for broader applications in the future.
Microstructure and Corrosion Resistance of Ti6Al4V Manufactured by Laser Powder Bed Fusion
Authors: Luo Yiwa , Wang Mingyong , Zhu Jun , Tu Jiguo , Jiao Shuqiang
Published: March 2023

Laser powder bed fusion (LPBF) technology has a dominant position in the preparation of titanium implants with a complex structure and precise size. However, the processing characteristics of rapid melting and solidification lead to the low density and poor corrosion resistance of the alloy. Hereby, the effects of the laser power and scanning rate on the density, hardness, compressive strength, and corrosion resistance of the Ti6Al4V alloy prepared by LPBF technology have been investigated by metallographic microscopy, a mechanical analysis, and electrochemical tests. The results show that increasing the scanning rate and decreasing the laser power decreases the transformation power from the β phase to α′ phase and changes the morphology of the α′ phase from lath shaped to acicular. The hardness of the Ti6Al4V alloy reaches the maximum (480.53 HV) for a scanning rate of 1000 mm/s and laser power of 280 W, owing to the sufficient precipitation of the α′ phase. Unfused holes occur in the titanium alloy when the laser energy density is too low to melt the power. Pores occur when the laser energy density is too high to vaporize the powder. Both defects reduce the compressive strength of the alloy. The maximum relative density of the Ti6Al4V alloy is 99.96% for a scanning rate of 1200 mm/s and laser power of 240 W, and the compressive strength (1964 MPa) and corrosion resistance (3.16 MΩ·cm2) both reached the maximum.
Tapered Optical Fiber Sensor Coated with Single-Walled Carbon Nanotubes for Dye Sensing Application
Authors: Polokhin Aleksandr A. , Shaman Yuri P. , Itrin Pavel A. , Panyaev Ivan S. , Sysa Artem A. , Selishchev Sergey V. , Kitsyuk Evgeny P. , Pavlov Alexander A. , Gerasimenko Alexander Yu.
Published: March 2023

The present study aimed to improve the optical sensing performance of tapered optical fiber sensors toward aqueous Rhodamine B solution of different concentrations by applying single-walled carbon nanotubes (SWCNTs). The functional coating was formed on the surface of the tapered optical fiber sensor using an aerosol layer-by-layer deposition method. Before deposition, the SWCNTs were processed with multistage liquid-phase treatment in order to form a stable dispersion. The effect of SWCNT treatment was investigated through Raman spectroscopy. The deposition of 220 layers caused a reduction of up to 60% of the initial optical power of radiation propagating through the optical fiber core. The optical fiber sensor coated with SWCNTs demonstrated significantly higher sensitivity compared to a non-coated sensor in the range of 2–32 mg/L of Rhodamine B concentration in an aqueous solution. The experimental results demonstrated that the sensitivity was increased 10 times from 32 (mg/L)−1, for the non-coated sensor, up to 317 (mg/L)−1 after SWCNT coating deposition. Moreover, the SWCNT-coated sensor demonstrated high repeatability that allowed for the evaluation of the concentration regardless of the previously analyzed dye concentration.
Analysis of Von Kármán Swirling Flows Due to a Porous Rotating Disk Electrode
Authors: Visuvasam James , Alotaibi Hammad
Published: March 2023

The study of Von Kármán swirling flow is a subject of active interest due to its applications in a wide range of fields, including biofuel manufacturing, rotating heat exchangers, rotating disc reactors, liquid metal pumping engines, food processing, electric power generating systems, designs of multi-pore distributors, and many others. This paper focusses on investigating Von Kármán swirling flows of viscous incompressible fluid due to a rotating disk electrode. The model is based on a system of four coupled second-order non-linear differential equations. The purpose of the present communication is to derive analytical expressions of velocity components by solving the non-linear equations using the homotopy analysis method. Combined effects of the slip λ and porosity γ parameters are studied in detail. If either parameter is increased, all velocity components are reduced, as both have the same effect on the mean velocity profiles. The porosity parameter γ increases the moment coefficient at the disk surface, which monotonically decreases with the slip parameter λ. The analytical results are also compared with numerical solutions, which are in satisfactory agreement. Furthermore, the effects of porosity and slip parameters on velocity profiles are discussed.
Bi2Te3 Thin Films Deposited by the Combination of Bi and Te Plasmas in a PLD Process
Authors: Reyes-Verdugo Laura A. , Gutiérrez-Lazos C. D. , Santos-Cruz J. , Chávez-Chávez A. , Quiñones-Galván J. G.
Published: March 2023

Bismuth telluride thin films were grown by pulsed laser deposition by implementing a novel method that combines both Te and Bi plasmas resulting from the laser ablation of individual Bi and Te targets. Furthermore, the mean kinetic ion energy and density of the plasmas, as estimated by TOF curves obtained from Langmuir probe measurements, were used as control parameters for the deposition process. The obtained thin films exhibit a metallic mirror-like appearance and present good adhesion to the substrate. Morphology of the thin films was observed by SEM, yielding smooth surfaces where particulates were also observed (splashing). Chemical composition analysis obtained by EDS showed that apparently the films have a Te-rich composition (ratio of Te/Bi of 3); however, Te excess arises from the splashing as revealed by the structural characterization (XRD and Raman spectroscopy). The XRD pattern indicated that depositions have the rhombohedral (D3d5 (R3¯m)) structure of Bi2Te3. Likewise, Raman spectra exhibited the presence of signals that correspond to Eg2, A1u2 and A1g2(LO) vibrational modes of the same rhombohedral phase of Bi2Te3. Additionally, oxidation states, analyzed by XPS, resulted in signals associated to Bi3+ and Te2- that correspond to the Bi2Te3 compound. Finally, surface topology and thickness profiles were obtained from AFM measurements, confirming a combination of a smooth surface with particulates on top of it and a film thickness of 400 nm.
Christian Orthodox Fasting as a Traditional Diet with Low Content of Refined Carbohydrates That Promotes Human Health: A Review of the Current Clinical Evidence
Authors: Giaginis Constantinos , Mantzorou Maria , Papadopoulou Sousana K. , Gialeli Maria , Troumbis Andreas Y. , Vasios Georgios K.
Published: March 2023

Introduction: Christian Orthodox fasting is a pattern high in complex carbohydrates and low in refined carbohydrates. It has been explored in association with its potential health benefits. The present review aims to comprehensively explore the existing available clinical data concerning the potential favorable impact of the dietary pattern of Christian Orthodox fasting on human health. Methods: PubMed database, Web of Science and Google Scholar were extensively searched in order to identify the more appropriate clinical studies that explore the effect of Christian Orthodox fasting on health-related outcomes in humans utilizing relative keywords. We initially retrieved 121 records through database searching. After applying several exclusion criteria, 17 clinical studies were finally included in this review study. Discussion: Christian Orthodox fasting showed beneficial effects concerning glucose and lipid control, whereas the data for blood pressure remain inconclusive. Concerning weight control, fasters were characterized by lower body mass and lower caloric intake in the course of the fasting periods. During fasting, this pattern is higher in fruits and vegetables, showing the absence of dietary deficiencies for iron and folate. Nevertheless, dietary deficiencies were recorded for calcium and vitamin B2, and also hypovitaminosis D has been noticed in monks. Interestingly, the vast majority of monks do present with both good quality of life and mental health. Conclusions: Overall, Christian Orthodox fasting is a dietary pattern low in refined carbohydrates and high in complex carbohydrates and fiber that may be beneficial for human health promotion and chronic disease prevention. However, further studies are strongly recommended on the impact of long-term religious fasting on HDL cholesterol levels and blood pressure.
Estimation of Glomerular Filtration Rate in Obese Patients: Utility of a New Equation
Authors: Fernández Pehuén , Nores María Laura , Douthat Walter , de Arteaga Javier , Luján Pablo , Campazzo Mario , de La Fuente Jorge , Chiurchiu Carlos
Published: March 2023

There is no consensus on the best equation to estimate glomerular filtration rate (eGFR) in obese patients (OP). Objective: to evaluate the performance of the current equations and the new Argentinian Equation (“AE”) to estimate GFR in OP. Two validation samples were used: internal (IVS, using 10-fold cross-validation) and temporary (TVS). OP whose GFR was measured (mGFR) with clearance of iothalamate between 2007/2017 (IVS, n = 189) and 2018/2019 (TVS, n = 26) were included. To evaluate the performance of the equations we used: bias (difference between eGFR and mGFR), P30 (percentage of estimates within ±30% of mGFR), Pearson’s correlation (r) and percentage of correct classification (%CC) according to the stages of CKD. The median age was 50 years. Sixty percent had grade I obesity (G1-Ob), 25.1% G2-Ob and 14.9% G3-Ob, with a wide range in mGFR (5.6–173.1 mL/min/1.73 m2). In the IVS, AE obtained a higher P30 (85.2%), r (0.86) and %CC (74.4%), with lower bias (−0.4 mL/min/1.73 m2). In the TVS, AE obtained a higher P30 (88.5%), r (0.89) and %CC (84.6%). The performance of all equations was reduced in G3-Ob, but AE was the only one that obtained a P30 > 80% in all degrees. AE obtained better overall performance to estimate GFR in OP and could be useful in this population. Conclusions from this study may not be generalizable to all populations of obese patients since they were derived from a study in a single center with a very specific ethnic mixed population.
Focusing on Phosphorus Loads: From Healthy People to Chronic Kidney Disease
Authors: Wang Mengjing , Zhang Jiaying , Kalantar-Zadeh Kamyar , Chen Jing
Published: March 2023

Phosphorus is an essential micromineral with a key role in cellular metabolism and tissue structure. Serum phosphorus is maintained in a homeostatic range by the intestines, bones, and kidneys. This process is coordinated by the endocrine system through the highly integrated actions of several hormones, including FGF23, PTH, Klotho, and 1,25D. The excretion kinetics of the kidney after diet phosphorus load or the serum phosphorus kinetics during hemodialysis support that there is a “pool” for temporary phosphorus storage, leading to the maintenance of stable serum phosphorus levels. Phosphorus overload refers to a state where the phosphorus load is higher than is physiologically necessary. It can be caused by a persistently high-phosphorus diet, renal function decline, bone disease, insufficient dialysis, and inappropriate medications, and includes but is not limited to hyperphosphatemia. Serum phosphorus is still the most commonly used indicator of phosphorus overload. Trending phosphorus levels to see if they are chronically elevated is recommended instead of a single test when judging phosphorus overload. Future studies are needed to validate the prognostic role of a new marker or markers of phosphorus overload.
Circulating Levels of Nesfatin-1 and Spexin in Children with Prader-Willi Syndrome during Growth Hormone Treatment and Dietary Intervention
Authors: Gajewska Joanna , Szamotulska Katarzyna , Klemarczyk Witold , Chełchowska Magdalena , Strucińska Małgorzata , Ambroszkiewicz Jadwiga
Published: March 2023

Background: Despite observable improvement in the treatment outcomes of patients with Prader-Willi syndrome (PWS), adequate weight control is still a clinical problem. Therefore, the aim of this study was to analyze the profiles of neuroendocrine peptides regulating appetite—mainly nesfatin-1 and spexin—in children with PWS undergoing growth hormone treatment and reduced energy intake. Methods: Twenty-five non-obese children (aged 2–12 years) with PWS and 30 healthy children of the same age following an unrestricted age-appropriate diet were examined. Serum concentrations of nesfatin-1, spexin, leptin, leptin receptor, total adiponectin, high molecular weight adiponectin, proinsulin, insulin-like growth factor-I, and total and functional IGF-binding protein-3 concentrations were determined using immunoenzymatic methods. Results: The daily energy intake in children with PWS was lower by about 30% (p < 0.001) compared with the controls. Daily protein intake was similar in both groups, but carbohydrate and fat intakes were significantly lower in the patient group than the controls (p < 0.001). Similar values for nesfatin-1 in the PWS subgroup with BMI Z-score < −0.5 and the control group, while higher values in the PWS subgroup with BMI Z-score ≥ −0.5 (p < 0.001) were found. Spexin concentrations were significantly lower in both subgroups with PWS than the controls (p < 0.001; p = 0.005). Significant differences in the lipid profile between the PWS subgroups and the controls were also observed. Nesfatin-1 and leptin were positively related with BMI (p = 0.018; p = 0.001, respectively) and BMI Z-score (p = 0.031; p = 0.027, respectively) in the whole group with PWS. Both neuropeptides also correlated positively in these patients (p = 0.042). Conclusions: Altered profiles of anorexigenic peptides—especially nesfatin-1 and spexin—in non-obese children with Prader-Willi syndrome during growth hormone treatment and reduced energy intake were found. These differences may play a role in the etiology of metabolic disorders in Prader-Willi syndrome despite the applied therapy.
Impact of Prenatal Health Conditions and Health Behaviors in Pregnant Women on Infant Birth Defects in the United States Using CDC-PRAMS 2018 Survey
Authors: Shelke Girish Suresh , Marwaha Rochisha , Shah Pankil , Challa Suman N.
Published: March 2023

Objective: To assess both individual and interactive effects of prenatal medical conditions depression and diabetes, and health behaviors including smoking during pregnancy on infant birth defects. Methods: The data for this research study were collected by the Pregnancy Risk Assessment Monitoring System (PRAMS) in 2018. Birth certificate records were used in each participating jurisdiction to select a sample representative of all women who delivered a live-born infant. Complex sampling weights were used to analyze the data with a weighted sample size of 4,536,867. Descriptive statistics were performed to explore frequencies of the independent and dependent variables. Bivariate and multivariable analyses were conducted to examine associations among the independent and dependent variables. Results: The results indicate significant interaction between the variables smoking and depression and depression and diabetes (OR = 3.17; p-value < 0.001 and OR = 3.13; p-value < 0.001, respectively). Depression during pregnancy was found to be strongly associated with delivering an infant with a birth defect (OR = 1.31, p-value < 0.001). Conclusion: Depression during pregnancy and its interaction with smoking and diabetes are vital in determining birth defects in infants. The results indicate that birth defects in the United States can be reduced by lowering depression in pregnant women.
Impact of Duodenal Pathology on Oral Drug Bioavailability and Disease Outcomes in Pediatric Crohn’s Disease
Authors: Casini Rebecca , Vyhlidal Carrie A. , Bracken Julia M. , Sherman Ashley K. , Ahmed Atif , Singh Vivekanand , Williams Veronica , Shakhnovich Valentina
Published: March 2023

Background: Crohn’s disease with upper gastrointestinal tract involvement occurs more often in children than adults and has the potential to interfere with oral drug absorption. We aimed to compare disease outcomes in children receiving oral azathioprine for the treatment of Crohn’s disease with (DP) and without (NDP) duodenal pathology at diagnosis. Methods: Duodenal villous length, body mass index (BMI), and laboratory studies were compared in DP vs. NDP during the first year post-diagnosis, using parametric/nonparametric tests and regression analysis (SAS v9.4); the data are reported as the median (interquartile range) or the mean ± standard deviation. Thiopurine metabolite concentration (pmol/8 × 108 erythrocytes) 230–400 was considered therapeutic for 6-thioguanine nucleotides (6-TGN), and >5700 was considered hepatotoxic for 6-methylmercaptopurine (6-MMPN). Results: Twenty-six of the fifty-eight children enrolled (29 DP, 29 NDP) started azathioprine for standard medical care, including nine DP and ten NDP who had normal thiopurine methyltransferase activity. Duodenal villous length was significantly shorter in DP vs. NDP (342 ± 153 vs. 460 ± 85 μm; p < 0.001) at diagnosis; age, sex, hemoglobin, and BMI were comparable between groups. A trend toward lower 6-TGN was observed in the DP vs. NDP subset receiving azathioprine (164 (117, 271) vs. 272 (187, 331); p = 0.15). Compared to NDP, DP received significantly higher azathioprine doses (2.5 (2.3, 2.6) vs. 2.2 (2.0, 2.2) mg/kg/day; p = 0.01) and had an increased relative risk of sub-therapeutic 6-TGN. At 9 months post-diagnosis, children with DP had significantly lower hemoglobin (12.5 (11.7, 12.6) vs. 13.1 (12.7, 13.3) g/dL; p = 0.01) and BMI z-scores (−0.29 (−0.93, −0.11) vs. 0.88 (0.53, 0.99); p = 0.02) than children with NDP. Conclusion: For children with Crohn’s disease, duodenal pathology, marked by villous blunting, increased the risk of sub-therapeutic 6-TGN levels, despite higher azathioprine dosing during the first year post-diagnosis. Lower hemoglobin and BMI z-scores at 9 months post-diagnosis suggest the impaired absorption/bioavailability of nutrients, as well as oral drugs, in children with duodenal disease.
Effect of Polymer Matrix on Inelastic Strain Development in PI- and PEI-Based Composites Reinforced with Short Carbon Fibers under Low-Cyclic Fatigue
Authors: Panin Sergey V. , Bogdanov Alexey A. , Eremin Alexander V. , Buslovich Dmitry G. , Shilko Ivan S.
Published: March 2023

Since the inelastic strain development plays an important role in the low-cycle fatigue (LCF) of High-Performance Polymers (HPPs), the goal of the research was to study the effect of an amorphous polymer matrix type on the resistance to cyclic loading for both polyimide (PI)- and polyetherimide (PEI)-based composites, identically loaded with short carbon fibers (SCFs) of various lengths, in the LCF mode. The fracture of the PI and PEI, as well as their particulate composites loaded with SCFs at an aspect ratio (AR) of 10, occurred with a significant role played by cyclic creep processes. Unlike PEI, PI was less prone to the development of creep processes, probably because of the greater rigidity of the polymer molecules. This increased the stage duration of the accumulation of scattered damage in the PI-based composites loaded with SCFs at AR = 20 and AR = 200, causing their greater cyclic durability. In the case of SCFs 2000 µm long, the length of the SCFs was comparable to the specimen thickness, causing the formation of a spatial framework of unattached SCFs at AR = 200. The higher rigidity of the PI polymer matrix provided more effective resistance to the accumulation of scattered damage with the simultaneously higher fatigue creep resistance. Under such conditions, the adhesion factor exerted a lesser effect. As shown, the fatigue life of the composites was determined both by the chemical structure of the polymer matrix and the offset yield stresses. The essential role of the cyclic damage accumulation in both neat PI and PEI, as well as their composites reinforced with SCFs, was confirmed by the results of XRD spectra analysis. The research holds the potential to solve problems related to the fatigue life monitoring of particulate polymer composites.
3,4-Enhanced Polymerization of Isoprene Catalyzed by Side-Arm Tridentate Iminopyridine Iron Complex with High Activity: Optimization via Response Surface Methodology
Authors: Han Zhenyu , Zhang Yongqiang , Wang Liang , Zhu Guangqian , Kuang Jia , Zhu Guangyu , Xu Guangqiang , Wang Qinggang
Published: March 2023

3,4-Enhanced polymerization of isoprene catalyzed by late transition metal with high activity remains one of the great challenges in synthetic rubber chemistry. Herein, a library of [N, N, X] tridentate iminopyridine iron chloride pre-catalysts (Fe 1–4) with the side arm were synthesized and confirmed by the element analysis and HRMS. All the iron compounds served as highly efficient pre-catalysts for 3,4-enhanced (up to 62%) isoprene polymerization when 500 equivalent MAOs were utilized as co-catalysts, delivering the corresponding high-performance polyisoprenes. Furthermore, optimization via single factor and response surface method, it was observed that the highest activity was obtained by complex Fe 2 with 4.0889 × 107 g·mol(Fe)−1·h−1 under the following conditions: Al/Fe = 683; IP/Fe = 7095; t = 0.52 min.
The Use of Kenaf Fibre as a Natural Anti-Degradant in Recycled High-Density Polyethylene and Natural Rubber-Based Thermoplastic Elastomers
Authors: Hayeemasae Nabil , Viet Cao Xuan , Masa Abdulhakim , Shuib Raa Khimi , Ismail Hanafi , Surya Indra
Published: March 2023

As most plastic materials disintegrate without being properly reused after they are discarded, this present study developed a novel thermoplastic elastomer (TPE) using recycled high-density polyethylene (rHDPE) and natural rubber (NR) with kenaf fibre as a sustainable filler. Apart from being used as filler, this present study aimed to examine the use of kenaf fibre as a natural anti-degradant as well. The results indicated that the tensile strength of the samples was found to have significantly decreased after 6 months of natural weathering and had decreased by a further 30% after 12 months due to the chain scission of the polymeric backbones and the degradation of the kenaf fibre. However, the composites that contained kenaf fibre significantly retained their properties post-natural weathering. In terms of tensile strength and elongation at the break, the addition of only 10 phr of kenaf increased the retention properties by 25% and 5%, respectively. This is noteworthy as kenaf fibre also contains a certain amount of natural anti-degradants. Therefore, as the kenaf fibre improves the weather resistance of composites, plastic manufacturers could use it as either a filler or a natural anti-degradant.
Centrifugal Force-Spinning to Obtain Multifunctional Fibers of PLA Reinforced with Functionalized Silver Nanoparticles
Authors: Martín-Alonso María Dolores , Salaris Valentina , Leonés Adrián , Hevilla Víctor , Muñoz-Bonilla Alexandra , Echeverría Coro , Fernández-García Marta , Peponi Laura , López Daniel
Published: March 2023

The design and development of multifunctional fibers awakened great interest in biomaterials and food packaging materials. One way to achieve these materials is by incorporating functionalized nanoparticles into matrices obtained by spinning techniques. Here, a procedure for obtaining functionalized silver nanoparticles through a green protocol, using chitosan as a reducing agent, was implemented. These nanoparticles were incorporated into PLA solutions to study the production of multifunctional polymeric fibers by centrifugal force-spinning. Multifunctional PLA-based microfibers were obtained with nanoparticle concentrations varying from 0 to 3.5 wt%. The effect of the incorporation of nanoparticles and the method of preparation of the fibers on the morphology, thermomechanical properties, biodisintegration, and antimicrobial behavior, was investigated. The best balance in terms of thermomechanical behavior was obtained for the lowest amount of nanoparticles, that is 1 wt%. Furthermore, functionalized silver nanoparticles confer antibacterial activity to the PLA fibers, with a percentage of killing bacteria between 65 and 90%. All the samples turned out to be disintegrable under composting conditions. Additionally, the suitability of the centrifugal force-spinning technique for producing shape-memory fiber mats was tested. Results demonstrate that with 2 wt% of nanoparticles a good thermally activated shape-memory effect, with high values of fixity and recovery ratios, is obtained. The results obtained show interesting properties of the nanocomposites to be applied as biomaterials.
Investigation on the Effect of Calcium on the Properties of Geopolymer Prepared from Uncalcined Coal Gangue
Authors: Wang Qingping , Zhu Longtao , Lu Chunyang , Liu Yuxin , Yu Qingbo , Chen Shuai
Published: March 2023

In this paper, the influence of calcium on coal gangue and fly ash geopolymer is explored, and the problem of low utilization of unburned coal gangue is analyzed and solved. The experiment took uncalcined coal gangue and fly ash as raw materials, and a regression model was developed with the response surface methodology. The independent variables were the CG content, alkali activator concentration, and Ca(OH)2 to NaOH ratio (CH/SH). The response target value was the coal gangue and fly-ash geopolymer compressive strength. The compressive strength tests and the regression model obtained by the response surface methodology showed that the coal gangue and fly ash geopolymer prepared with the content of uncalcined coal gangue is 30%, alkali activator content of 15%, and the value of CH/SH is 1.727 had a dense structure and better performance. The microscopic results demonstrated that the uncalcined coal gangue structure is destroyed under an alkali activator’s action, and a dense microstructure is formed based on C(N)-A-S-H and C-S-H gel, which provides a reasonable basis for the preparation of geopolymers from the uncalcined coal gangue.
Dynamic Wetting Properties of Silica-Poly (Acrylic Acid) Superhydrophilic Coatings
Authors: Turkoglu Sevil , Zhang Jinde , Dodiuk Hanna , Kenig Samuel , Ratto Jo Ann , Mead Joey
Published: March 2023

Superhydrophilic coatings based on a hydrophilic silica nanoparticle suspension and Poly (acrylic acid) (PAA) were prepared by dip coating. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) were used to examine the morphology of the coating. The effect of surface morphology on the dynamic wetting behavior of the superhydrophilic coatings was studied by changing the silica suspension concentration from 0.5% wt. to 3.2% wt. while keeping the silica concentration in the dry coating constant. The droplet base diameter and dynamic contact angle with respect to time were measured using a high-speed camera. A power law was found to describe the relationship between the droplet diameter and time. A significantly low experimental power law index was obtained for all the coatings. Both roughness and volume loss during spreading were suggested to be responsible for the low index values. The water adsorption of the coatings was found to be the reason for the volume loss during spreading. The coatings exhibited good adherence to the substrates and retention of hydrophilic properties under mild abrasion.
Experimental Analysis of Fiber Reinforcement Rings’ Effect on Tensile and Flexural Properties of Onyx™–Kevlar® Composites Manufactured by Continuous Fiber Reinforcement
Authors: Moreno-Núñez Benjamín Alberto , Abarca-Vidal César Gustavo , Treviño-Quintanilla Cecilia D. , Sánchez-Santana Ulises , Cuan-Urquizo Enrique , Uribe-Lam Esmeralda
Published: March 2023

Additive manufacturing of composite materials is progressing in the world of 3D printing technologies; composite materials allow the combination of the physical and mechanical properties of two or more constituents to create a new material that meets the required properties of several applications. In this research, the impact of adding Kevlar® reinforcement rings on the tensile and flexural properties of the Onyx™ (nylon with carbon fibers) matrix was analyzed. Parameters such as infill type, infill density and fiber volume percentage were controlled to determine the mechanical response in tensile and flexural tests of the additive manufactured composites. The tested composites showed an increment of four times the tensile modulus and 1.4 times the flexural modulus of pure Onyx™ matrix when compared with that of the Onyx™–Kevlar®. The experimental measurements demonstrated that Kevlar® reinforcement rings can increase the tensile and flexural modulus of Onyx™–Kevlar® composites using low fiber volume percentages (lower than 19% in both samples) and 50% of rectangular infill density. However, the appearance of some defects, such as delamination, was observed and should be further analyzed to obtain products that are errorless and can be reliable for real functions as in automotive or aeronautical industries.
Constancy and Changes in the Distribution of Religious Groups in Contemporary China: Centering on Religion as a Whole, Buddhism, Protestantism and Folk Religion
Authors: Li Feng , Wang Qian
Published: March 2023

Since 1978, mass religious conversion has been a prominent feature of Chinese religious life. In the 1980s and 1990s, the “Five types of believers’ distribution (Wuduo, 五多)” were characterized by the inclusion of “more women”, “more elderly”, “more sick people”, “more rural residents”, and “more people with lower socioeconomic status”, as is the academic consensus. In the 21st century, some scholars have proposed the different view of “Three trends in faith stratification (Sanhua, 三化)”, namely urbanization, rejuvenation, and elitism. However, these claims are either based on theoretical analysis or local cases and data analysis. Based on the Chinese General Social Survey (CGSS) data from 2010 to 2017, this study constructed a comprehensive explanatory framework with macroscopic, mesoscopic, and microcosmic levels to verify the authenticity of the two sets of propositions by taking religion as a whole and also examining some representative religions such as Buddhism, Protestantism and folk religion. The results show that they are partially invalid, and thus, need to be further refined to be explained; the distribution of believer groups varies among religions and between urban/rural areas.
Potential Assessment of PRISMA Hyperspectral Imagery for Remote Sensing Applications
Authors: Shaik Riyaaz Uddien , Periasamy Shoba , Zeng Weiping
Published: March 2023

Hyperspectral imagery plays a vital role in precision agriculture, forestry, environment, and geological applications. Over the past decade, extensive research has been carried out in the field of hyperspectral remote sensing. First introduced by the Italian Space Agency ASI in 2019, space-borne PRISMA hyperspectral imagery (PHSI) is taking the hyperspectral remote sensing research community into the next era due to its unprecedented spectral resolution of ≤12 nm. Given these abundant free data and high spatial resolution, it is crucial to provide remote sensing researchers with information about the critical attributes of PRISMA imagery, making it the most viable solution for various land and water applications. Hence, in the present study, a SWOT analysis was performed for PHSI using recent case studies to exploit the potential of PHSI for different remote sensing applications, such as snow, soil, water, natural gas, and vegetation. From this analysis, it was found that the higher reflectance spectra of PHSI, which have comprehensive coverage, have greater potential to extract vegetation biophysical parameters compared to other applications. Though the possible use of these data was demonstrated in a few other applications, such as the identification of methane gases and soil mineral mapping, the data may not be suitable for continuous monitoring due to their limited acquisition, long revisiting times, noisy bands, atmospheric interferences, and computationally heavy processing, particularly when executing machine learning models. The potential applications of PHSI include large-scale and efficient mapping, transferring technology, and fusion with other remote sensing data, whereas the lifetime of satellites and the need for interdisciplinary personnel pose challenges. Furthermore, some strategies to overcome the aforementioned weaknesses and threats are described in our conclusions.
MAFF-HRNet: Multi-Attention Feature Fusion HRNet for Building Segmentation in Remote Sensing Images
Authors: Che Zhihao , Shen Li , Huo Lianzhi , Hu Changmiao , Wang Yanping , Lu Yao , Bi Fukun
Published: March 2023

Built-up areas and buildings are two main targets in remote sensing research; consequently, automatic extraction of built-up areas and buildings has attracted extensive attention. This task is usually difficult because of boundary blur, object occlusion, and intra-class inconsistency. In this paper, we propose the multi-attention feature fusion HRNet, MAFF-HRNet, which can retain more detailed features to achieve accurate semantic segmentation. The design of a pyramidal feature attention (PFA) hierarchy enhances the multilevel semantic representation of the model. In addition, we develop a mixed convolutional attention (MCA) block, which increases the capture range of receptive fields and overcomes the problem of intra-class inconsistency. To alleviate interference due to occlusion, a multiscale attention feature aggregation (MAFA) block is also proposed to enhance the restoration of the final prediction map. Our approach was systematically tested on the WHU (Wuhan University) Building Dataset and the Massachusetts Buildings Dataset. Compared with other advanced semantic segmentation models, our model achieved the best IoU results of 91.69% and 68.32%, respectively. To further evaluate the application significance of the proposed model, we migrated a pretrained model based on the World-Cover Dataset training to the Gaofen 16 m dataset for testing. Quantitative and qualitative experiments show that our model can accurately segment buildings and built-up areas from remote sensing images.
UWB Localization Based on Improved Robust Adaptive Cubature Kalman Filter
Authors: Dong Jiaqi , Lian Zengzeng , Xu Jingcheng , Yue Zhe
Published: March 2023

Aiming at the problems of Non-Line-of-Sight (NLOS) observation errors and inaccurate kinematic model in ultra-wideband (UWB) systems, this paper proposed an improved robust adaptive cubature Kalman filter (IRACKF). Robust and adaptive filtering can weaken the influence of observed outliers and kinematic model errors on filtering, respectively. However, their application conditions are different, and improper use may reduce positioning accuracy. Therefore, this paper designed a sliding window recognition scheme based on polynomial fitting, which can process the observation data in real-time to identify error types. Simulation and experimental results indicate that compared to the robust CKF, adaptive CKF, and robust adaptive CKF, the IRACKF algorithm reduces the position error by 38.0%, 45.1%, and 25.3%, respectively. The proposed IRACKF algorithm significantly improves the positioning accuracy and stability of the UWB system.