bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative Analysis of the Prevalence of Dysphagia in Patients with Mild COVID-19 and Those with Aspiration Pneumonia Alone: Findings of the Videofluoroscopic Swallowing Study
Authors: Kim Junhyung , Ryu Byungju , Kim Yunhee , Choi Yireh , Lee Eunyoung
Published: October 2023

Background and Objectives: Patients recovering from mild coronavirus disease (COVID-19) reportedly have dysphagia or difficulty in swallowing. We compared the prevalence of dysphagia between patients diagnosed with mild COVID-19 and those diagnosed with aspiration pneumonia alone. Materials and Methods: A retrospective study was conducted from January 2020 to June 2023 in 160 patients referred for a videofluoroscopic swallowing study (VFSS) to assess for dysphagia. The cohort included 24 patients with mild COVID-19 and aspiration pneumonia, 30 with mild COVID-19 without aspiration pneumonia, and 106 with aspiration pneumonia alone. We reviewed the demographic data, comorbidities, and VFSS results using the penetration–aspiration scale (PAS) and functional dysphagia scale (FDS). Results: In a study comparing patients with mild COVID-19 (Group A) and those with aspiration pneumonia alone (Group B), no significant differences were observed in the baseline characteristics, including the prevalence of dysphagia-related comorbidities between the groups. Group A showed milder dysphagia, as evidenced by lower PAS and FDS scores, shorter oral and pharyngeal transit times (p = 0.001 and p = 0.003, respectively), and fewer residues in the vallecula and pyriform sinuses (p < 0.001 and p < 0.03, respectively). When Group A was subdivided into those with COVID-19 with (Group A1) and without aspiration pneumonia (Group A2), both subgroups outperformed Group B in terms of specific VFSS metrics, such as oral transit time (p = 0.01), pharyngeal transit time (p = 0.04 and p = 0.02, respectively), and residue in the vallecula (p = 0.04 and p = 0.02, respectively). However, Group B showed improved triggering of the pharyngeal swallowing reflex compared with Group A2 (p = 0.02). Conclusion: Mild COVID-19 patients showed less severe dysphagia than those with aspiration pneumonia alone. This finding was consistent across VFSS parameters, even when the COVID-19 group was subdivided based on the status of aspiration pneumonia.
Rheumatoid Arthritis Has Won the Battle but Not the War: How Many Joints Will We Save Tomorrow?
Authors: Oberemok Volodymyr V. , Andreeva Oksana , Laikova Kateryna , Alieva Edie , Temirova Zenure
Published: October 2023

Rheumatoid arthritis refers to joint diseases of unclear etiology whose final stages can lead to unbearable pain and complete immobility of the affected joints. As one of the most widely known diseases of the joints, it serves as a study target for a large number of research groups and pharmaceutical companies. Modern treatment with anti-inflammatory drugs, including janus kinase (JAK) inhibitors, monoclonal antibodies, and botanicals (polyphenols, glycosides, alkaloids, etc.) has achieved some success and hope for improving the course of the disease. However, existing drugs against RA have a number of side effects which push researchers to elaborate on more selective and effective drug candidates. The avant-garde of research, which aims to develop treatment of rheumatoid arthritis using antisense oligonucleotides along with nonsteroidal drugs and corticosteroids against inflammation, increases the chances of success and expands the arsenal of drugs. The primary goal in the treatment of this disease is to find therapies that allow patients with rheumatoid arthritis to move their joints without pain. The main purpose of this review is to show the victories and challenges for the treatment of rheumatoid arthritis and the tortuous but promising path of research that aims to help patients experience the joy of freely moving joints without pain.
Effect of Different Heat Treatments and Surface Treatments on the Mechanical Properties of Nickel-Titanium Rotary Files
Authors: Hong Jihye , Kwak Sang Won , Ha Jung-Hong , Sigurdsson Asgeir , Shen Ya , Kim Hyeon-Cheol
Published: October 2023

This study aimed to compare the fatigue resistance of files made from different heat treatment methods and surface treatment. Four prototype files were created through heat treatment and titanium coating surface treatment (AT, DT, ER, EN; named arbitrarily by the manufacturer) at different times and temperatures. Artificial canals with curvatures of 45- and 90-degree were used for the fatigue testing. The files were operated at the speed of 500 rpm at 37 °C, and the time until fracture incurred by a 4-mm dynamic pecking motion at a speed of 8 mm/s was measured, and the number of cycles to failure (NCF) was calculated by applying rotation speed and time. The length of the fractured fragment was measured. The fractured specimens were observed under the SEM to compare the characteristics of fatigue fracture patterns. Differential scanning calorimetry analysis was performed to estimate the phase transformation temperature. One-way ANOVA with Duncan’s post-hoc comparison, the Kruskal–Wallis test, and Mann–Whitney U were applied to compare the fatigue resistance among the prototypes at a significance level of 95%. Regardless of the canal angle, the EN showed the highest fatigue resistance (p < 0.05). AT had the lowest NCF at the 90-degree canal (p < 0.05). ER had a higher NCF than the DT at 45 degrees (p < 0.05), but there was no difference at 90 degrees. DSC analysis revealed that the ER and EN groups exhibited two austenite peaks above 40 °C. In conclusion, the file that underwent a specific temperature heat treatment with titanium coating surface treatment showed the highest fatigue resistance.
Brain Regulation of Cardiac Function during Hypoglycemia
Authors: Chambers Matthew E. , Nuibe Emily H. , Reno-Bernstein Candace M.
Published: October 2023

Hypoglycemia occurs frequently in people with type 1 and type 2 diabetes. Hypoglycemia activates the counter-regulatory response. Besides peripheral glucose sensors located in the pancreas, mouth, gastrointestinal tract, portal vein, and carotid body, many brain regions also contain glucose-sensing neurons that detect this fall in glucose. The autonomic nervous system innervates the heart, and during hypoglycemia, can cause many changes. Clinical and animal studies have revealed changes in electrocardiograms during hypoglycemia. Cardiac repolarization defects (QTc prolongation) occur during moderate levels of hypoglycemia. When hypoglycemia is severe, it can be fatal. Cardiac arrhythmias are thought to be the major mediator of sudden death due to severe hypoglycemia. Both the sympathetic and parasympathetic nervous systems of the brain have been implicated in regulating these arrhythmias. Besides cardiac arrhythmias, hypoglycemia can have profound changes in the heart and most of these changes are exacerbated in the setting of diabetes. A better understanding of how the brain regulates cardiac changes during hypoglycemia will allow for better therapeutic intervention to prevent cardiovascular death associated with hypoglycemia in people with diabetes. The aim of this paper is to provide a narrative review of what is known in the field regarding how the brain regulates the heart during hypoglycemia.
A Four Element Stringray-Shaped MIMO Antenna System for UWB Applications
Authors: Savcı Hüseyin Şerif
Published: October 2023

This paper presents a CoPlanar-Waveguide (CPW)-fed stingray-shaped Ultra-WideBand (UWB) Multiple-Input–Multiple-Output (MIMO) antenna system designed for microwave imaging applications. Featuring a diagonal square with four inner lines and a vertical line at the center from toe to tip with a CPW feed line, the unit antenna element looks like a stingray fish skeleton and is, therefore, named as a stingray-shaped antenna. It offers a bandwidth spanning from 3.8 to 12.7 GHz. Fabricated on a 31mil RO5880 RF teflon substrate with a relative permittivity of 2.2, the proposed antenna has dimensions of 26 × 29 × 0.787 mm3. The maximum realized gain achieved is 3.5 dBi with stable omnidirectional radiation patterns. The antenna element is used in a four-antenna MIMO configuration with an isolation-improving structure at the center. The MIMO system has dimensions of 58 × 58 × 0.787 mm3 with a maximum realized gain of 5.3 dBi. The antenna’s performance in terms of MIMO parameters like Envelope Correlation Coefficient (ECC) and Diversity Gain (DG) is within satisfactory limits for medical imaging applications. Time domain analysis also yields positive results, allowing its integration into a breast phantom tumor detection simulation. The simulation and measurement results demonstrate excellent agreement, making this antenna a promising candidate for microwave imaging and biomedical applications.
Highly Selective and Fast Response/Recovery Cataluminescence Sensor Based on SnO2 for H2S Detection
Authors: Fan Bin , Zhang Jing-Ru , Chen Jia-Liang , Yang Ze-Tao , Li Bin , Wang Lin , Ye Mai , Zhang Lu-Lu
Published: October 2023

In the present work, three kinds of nanosized SnO2 samples were successfully synthesized via a hydrothermal method with subsequent calcination at temperatures of 500 °C, 600 °C, and 700 °C. The morphology and structure of the as-prepared samples were characterized using X-ray diffraction, transmission electron microscopy, selected area electron diffraction, Brunauer–Emmett–Teller analysis, and X-ray photoelectron spectroscopy. The results clearly indicated that the SnO2 sample calcined at 600 °C had a higher amount of chemisorbed oxygen than the SnO2 samples calcined at 500 °C and 700 °C. Gas sensing investigations revealed that the cataluminescence (CTL) sensors based on the three SnO2 samples all exhibited high selectivity toward H2S, but the sensor based on SnO2−600 °C exhibited the highest response under the same conditions. At an operating temperature of 210 °C, the SnO2−600 °C sensor showed a good linear response to H2S in the concentration range of 20–420 ppm, with a detection limit of 8 ppm. The response and recovery times were 3.5 s/1.5 s for H2S gas within the linear range. The study on the sensing mechanism indicated that H2S was oxidized into excited states of SO2 by chemisorbed oxygen on the SnO2 surface, which was mainly responsible for CTL emission. The chemisorbed oxygen played an important role in the oxidation of H2S, and, as such, the reason for the SnO2−600 °C sensor showing the highest response could be ascribed to the highest amount of chemisorbed oxygen on its surface. The proposed SnO2-based gas sensor has great potential for the rapid monitoring of H2S.
Radiosynthesis and Early Evaluation of a Positron Emission Tomography Imaging Probe [18F]AGAL Targeting Alpha-Galactosidase A Enzyme for Fabry Disease
Authors: Lohith Talakad G. , Kaittanis Charalambos , Belanger Anthony P. , Ahn Shin Hye , Sandoval Phil , Cohen Lawrence , Rajarshi Girija , Ruangsiriluk Wanida , Islam Rizwana , Winkelmann Christopher T. , McQuade Paul
Published: October 2023

Success of gene therapy relies on the durable expression and activity of transgene in target tissues. In vivo molecular imaging approaches using positron emission tomography (PET) can non-invasively measure magnitude, location, and durability of transgene expression via direct transgene or indirect reporter gene imaging in target tissues, providing the most proximal PK/PD biomarker for gene therapy trials. Herein, we report the radiosynthesis of a novel PET tracer [18F]AGAL, targeting alpha galactosidase A (α-GAL), a lysosomal enzyme deficient in Fabry disease, and evaluation of its selectivity, specificity, and pharmacokinetic properties in vitro. [18F]AGAL was synthesized via a Cu-catalyzed click reaction between fluorinated pentyne and an aziridine-based galactopyranose precursor with a high yield of 110 mCi, high radiochemical purity of >97% and molar activity of 6 Ci/µmol. The fluorinated AGAL probe showed high α-GAL affinity with IC50 of 30 nM, high pharmacological selectivity (≥50% inhibition on >160 proteins), and suitable pharmacokinetic properties (moderate to low clearance and stability in plasma across species). In vivo [18F]AGAL PET imaging in mice showed high uptake in peripheral organs with rapid renal clearance. These promising results encourage further development of this PET tracer for in vivo imaging of α-GAL expression in target tissues affected by Fabry disease.
Bifunctional Al-Doped Cobalt Ferrocyanide Nanocube Array for Energy-Saving Hydrogen Production via Urea Electrolysis
Authors: Gao Xiafei , Gao Mengyue , Yu Xueping , Jin Xiaoyong , Ni Gang , Peng Juan
Published: October 2023

The very slow anodic oxygen evolution reaction (OER) greatly limits the development of large-scale hydrogen production via water electrolysis. By replacing OER with an easier urea oxidation reaction (UOR), developing an HER/UOR coupling electrolysis system for hydrogen production could save a significant amount of energy and money. An Al-doped cobalt ferrocyanide (Al-Co2Fe(CN)6) nanocube array was in situ grown on nickel foam (Al-Co2Fe(CN)6/NF). Due to the unique nanocube array structure and regulated electronic structure of Al-Co2Fe(CN)6, the as-prepared Al-Co2Fe(CN)6/NF electrode exhibited outstanding catalytic activities and long-term stability to both UOR and HER. The Al-Co2Fe(CN)6/NF electrode needed potentials of 0.169 V and 1.118 V (vs. a reversible hydrogen electrode) to drive 10 mA cm−2 for HER and UOR, respectively, in alkaline conditions. Applying the Al-Co2Fe(CN)6/NF to a whole-urea electrolysis system, 10 mA cm−2 was achieved at a cell voltage of 1.357 V, which saved 11.2% electricity energy compared to that of traditional water splitting. Density functional theory calculations demonstrated that the boosted UOR activity comes from Co sites with Al-doped electronic environments. This promoted and balanced the adsorption/desorption of the main intermediates in the UOR process. This work indicates that Co-based materials as efficient catalysts have great prospects for application in urea electrolysis systems and are expected to achieve low-cost and energy-saving H2 production.
Green Synthesis of Low-Glycemic Amylose–Lipid Nanocomposites by High-Speed Homogenization and Formulation into Hydrogel
Authors: Khan Nasir Mehmood , Uddin Misbah , Falade Ebenezer Ola , Khan Farman Ali , Wang Jian , Shafique Muhammad , Alnemari Reem M. , Abduljabbar Maram H. , Ahmad Shujaat
Published: October 2023

In this research, we focused on the production of amylose–lipid nanocomposite material (ALN) through a green synthesis technique utilizing high-speed homogenization. Our aim was to investigate this novel material’s distinctive physicochemical features and its potential applications as a low-glycemic gelling and functional food ingredient. The study begins with the formulation of the amylose–lipid nanomaterial from starch and fatty acid complexes, including stearic, palmitic, and lauric acids. Structural analysis reveals the presence of ester carbonyl functionalities, solid matrix structures, partial crystallinities, and remarkable thermal stability within the ALN. Notably, the ALN exhibits a significantly low glycemic index (GI, 40%) and elevated resistance starch (RS) values. The research extends to the formulation of ALN into nanocomposite hydrogels, enabling the evaluation of its anthocyanin absorption capacity. This analysis provides valuable insights into the rheological properties and viscoelastic behavior of the resulting hydrogels. Furthermore, the study investigates anthocyanin encapsulation and retention by ALN-based hydrogels, with a particular focus on the influence of pH and physical cross-link networks on the uptake capacity presenting stearic-acid (SA) hydrogel with the best absorption capacity. In conclusion, the green-synthesized (ALN) shows remarkable functional and structural properties. The produced ALN-based hydrogels are promising materials for a variety of applications, such as medicine administration, food packaging, and other industrial purposes.
Post-Synthetic Modification of an Amino-Functionalized Metal–Organic Framework for Highly In Situ Luminescent Detection of Mercury (II)
Authors: Ji Chen , Pei Li , Qin Junyi , Wu Pengyan , Su Nuo , Zhang Ting , Zhang Yexin , Wang Jian
Published: October 2023

A sulfur-containing metal–organic framework, donated as UiO-66-NSMe, was prepared by the post-synthetic modification (PSM) of UiO-66-NH2 with 2-(Methylthio)benzaldehyde, and the successful synthesis of PSM was confirmed by X-ray photoelectron spectroscopy (XPS), FT-IR and 1H NMR studies. According to the characteristics of mercury thiophilic, UiO-66-NSMe could be used as a luminescent sensor for Hg2+ detection with a high selectivity and sensitivity (Ksv = 2.5 × 104 M−1; LOD = 20 nM), which could be attributed to the coordination between sulfur sites and Hg2+ based on XPS results. In practical applications, UiO-66-NSMe yielded satisfactory recovery rates (ranging from 96.1% to 99.5%) when it was employed for detecting Hg2+ in spiked environmental samples. Furthermore, UiO-66-NSMe was successfully employed to detect mercury (II) residues with the in situ rapid nondestructive imaging in simulated fresh agricultural products. Thus, this PSM strategy could provide good guidance for environmental protection methodologies in the future.
Sociodemographic and Health Indicators of Diet Quality in Pre-Frail Older Adults in New Zealand
Authors: Tay Esther , Barnett Daniel , Rowland Maisie , Kerse Ngaire , Edlin Richard , Waters Debra L. , Connolly Martin , Pillai Avinesh , Tupou Evelingi , Teh Ruth
Published: October 2023

This study aimed to identify sociodemographic and health indicators of diet quality in pre-frail community-dwelling older adults. Pre-frail older adults are those at risk of progression to clinical manifestations of frailty and are targets for preventative intervention. We previously reported that pre-frail older adults have reasonably good overall diet quality. However, further analyses found a low intake of energy, protein and several micronutrients. Methods: We collected detailed dietary intake from pre-frail (FRAIL scale 1–2) older adults using NZ Intake24, an online version of 24 h multiple pass dietary recall. Diet quality was ascertained with the Diet Quality Index-International (DQI-I). We used regression generalized linear models to determine predictors of diet quality as well as classification and regression tree (CART) analysis to examine the complex relationships between predictors and identified profiles of sub-groups of older adults that predict diet quality. Results: The median age in this sample (n = 468) was 80.0 years (77.0–84.0). Living with others, a high deprivation index and a higher BMI were independent predictors of poorer diet quality. With CART analysis, we found that those with a BMI > 29 kg/m2, living with others and younger than 80 years were likely to have a lower diet quality. Conclusions: We found that BMI, living arrangement and socioeconomic status were independent predictors of diet quality in pre-frail older adults, with BMI being the most important variable in this sample when the interaction of these variables was considered. Future research is needed to determine the similarities and/or differences in the profile of subgroups of older adults with poorer diet quality.
No Changes in Body Composition and Adherence to the Mediterranean Diet after a 12-Week Aerobic Training Intervention in Women with Systemic Lupus Erythematosus: The EJERCITA-LES Study
Authors: Gavilán-Carrera Blanca , Ruiz-Cobo Alba , Amaro-Gahete Francisco , Soriano-Maldonado Alberto , Vargas-Hitos José
Published: October 2023

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease linked to high cardiovascular risk. To reach an adequate body composition status while maintaining proper dietary habits are effective strategies for reducing cardiovascular risk, both being potentially modified through exercise. This study aimed to evaluate the effects of a 12-week aerobic training intervention on anthropometry, body composition and adherence to the Mediterranean diet in women with SLE. A total of 58 women with SLE were assigned to either an exercise group (EG; n = 26) or a comparison group (CG; n = 32) in this non-randomized controlled trial. The EG comprised 12 weeks of aerobic exercise (two sessions/week) between 40–75% of the individual’s heart rate reserve (calculated as maximum heart rate − resting heart rate) and the CG received usual care. At baseline and after the intervention, the anthropometry (i.e., weight, waist circumference, waist-to-hip ratio, and body mass index) and body composition (i.e., fat mass and lean mass) were assessed using a stadiometer, an anthropometric tape, and a bioimpedance device, respectively. Dietary habits were assessed with the Mediterranean Diet score. There were no between-group differences in neither anthropometric nor body composition parameters (all p > 0.05). Similarly, no between-group differences were obtained in the adherence to the Mediterranean diet after the exercise intervention (all p > 0.05). Contrary to the initial hypothesis, these results suggest that the 12-week aerobic training intervention performed in this study did not improve anthropometry, body composition or adherence to the Mediterranean diet in women with SLE.
Design, Synthesis and Biological Evaluation of Novel N-Arylpiperazines Containing a 4,5-Dihydrothiazole Ring
Authors: Andreozzi Giorgia , Ambrosio Maria Rosaria , Magli Elisa , Maneli Giovanni , Severino Beatrice , Corvino Angela , Sparaco Rosa , Perissutti Elisa , Frecentese Francesco , Santagada Vincenzo , Leśniak Anna , Bujalska-Zadrożny Magdalena , Caliendo Giuseppe , Formisano Pietro , Fiorino Ferdinando
Published: October 2023

Arylpiperazines represent one of the most important classes of 5-HT1AR ligands and have attracted considerable interests for their versatile properties in chemistry and pharmacology, leading to the research of new derivatives that has been focused on the modification of one or more portions of such pharmacophore. An efficient protocol for the synthesis of novel thiazolinylphenyl-piperazines (2a–c) and the corresponding acetylated derivatives was used (3a–c). The new compounds were tested for their functional activity and affinity at 5-HT1A receptors, showing an interesting affinity profile with a Ki value of 412 nM for compound 2b. The cytotoxic activity of novel thiazolinylphenyl-piperazines (2a–c) and corresponding N-acetyl derivatives (3a–c) against human prostate and breast cancer cell lines (LNCAP, DU-145 and PC-3, MCF-7, SKBR-3 and MDA-MB231) was investigated according to the procedure described in the literature. The reported data showed a cytotoxic effect for 2a–c and 3a–c compounds (IC50 values ranging from 15 µM to 73 µM) on the investigated cancer cell lines, with no effect on noncancer cells. Future studies will be aimed to investigate the mechanism of action and therapeutic prospects of these new scaffolds.
1-Piperidine Propionic Acid as an Allosteric Inhibitor of Protease Activated Receptor-2
Authors: Chinellato Monica , Gasparotto Matteo , Quarta Santina , Ruvoletto Mariagrazia , Biasiolo Alessandra , Filippini Francesco , Spiezia Luca , Cendron Laura , Pontisso Patrizia
Published: October 2023

In the last decades, studies on the inflammatory signaling pathways in multiple pathological contexts have revealed new targets for novel therapies. Among the family of G-protein-coupled Proteases Activated Receptors, PAR2 was identified as a driver of the inflammatory cascade in many pathologies, ranging from autoimmune disease to cancer metastasis. For this reason, many efforts have been focused on the development of potential antagonists of PAR2 activity. This work focuses on a small molecule, 1-Piperidine Propionic Acid (1-PPA), previously described to be active against inflammatory processes, but whose target is still unknown. Stabilization effects observed by cellular thermal shift assay coupled to in-silico investigations, including molecular docking and molecular dynamics simulations, suggested that 1-PPA binds PAR2 in an allosteric pocket of the receptor inactive conformation. Functional studies revealed the antagonist effects on MAPKs signaling and on platelet aggregation, processes mediated by PAR family members, including PAR2. Since the allosteric pocket binding 1-PPA is highly conserved in all the members of the PAR family, the evidence reported here suggests that 1-PPA could represent a promising new small molecule targeting PARs with antagonistic activity.
Adjunct Nondamaging Focal Laser Reduces Intravitreal Injection Burden in Diabetic Macular Edema
Authors: Azzouz Lyna , Durrani Asad , Zhou Yunshu , Paulus Yannis M.
Published: October 2023

This study aims to determine the impact of adjunct nondamaging focal laser therapy on the number of anti-vascular endothelial growth factor (anti-VEGF) injections and visual acuity (VA) and imaging in patients with diabetic macular edema (DME). A retrospective analysis of 18 eyes of 14 patients with DME treated with a single session of the PASCAL 532 nm Synthesis Photocoagulator with Endpoint Management was conducted. Demographic data, VA, imaging, laser parameters, and anti-VEGF injection burden six months before and after treatment were collected. Wilcoxon Signed-rank tests were used to assess changes in VA and injection burden before and after treatment. The mean number of intravitreal injections in the six-month period prior to laser treatment was 3.39 ± 2.57 injections compared to 2.33 ± 2.40 injections following laser treatment (p = 0.02). There was no significant difference between the mean VA on the day of treatment logMAR VA of 0.38 ± 0.27 (approx. Snellen equivalent 20/50) and the visual acuity on the most recent follow-up 6 months after laser logMAR VA of 0.35 ± 0.32 (approx. Snellen equivalent 20/40) (p = 0.34). There was also no significant difference in OCT central macular thickness before (311 µm) compared to 6 months after (301 µm, p = 0.64). Adjunct focal macular laser therapy is associated with a statistically and clinically significant decrease in the number of intravitreal injections required in the six-month period immediately following treatment, without compromising visual acuity or macular thickness. Nondamaging focal laser has the potential to alleviate the burden of injections for both patients and clinics.
Effective Properties for the Design of Basalt Particulate–Polymer Composites
Authors: Yun Jong-Hwan , Jeon Yu-Jae , Kang Min-Soo
Published: October 2023

In this study, preliminary simulations were performed to manufacture thermoplastic composites that can be processed by injection. For analysis, a basalt particulate–polymer composite model was manufactured and its elastic modulus, shear modulus, thermal expansion coefficient, and thermal conductivity were predicted using finite-element analysis (FEA) and micromechanics. Polypropylene (PP), polyamide 6, polyamide 66, and polyamide (PA) were employed as the polymer matrix, with the variations in their properties investigated based on the volume fraction of basalt. The polymer–basalt composite’s properties were analyzed effectively using FEA and the micromechanics model. FEA was performed by constructing a 3D model based on the homogenization technique to analyze the effective properties. The micromechanics model was analyzed numerically using the mixture rule, and the Mital, Guth, and Halpin–Tsai models. As a result, it is best to analyze the effective properties of polymer–basalt composites using the Halpin–Tsai model, and it is necessary to conduct a comparative analysis through actual experiments. In the future, actual composite materials need to be developed and evaluated based on the findings of this study.
Impact of Multiple Reprocessing on Properties of Polyhydroxybutyrate and Polypropylene
Authors: Main Priyanka , Petersmann Sandra , Wild Nadine , Feuchter Michael , Duretek Ivica , Edeleva Mariya , Ragaert Peter , Cardon Ludwig , Lucyshyn Thomas
Published: October 2023

Biobased plastics have the potential to be sustainable, but to explore their circularity further, current end-of-life options need to be broadened. Mechanical recycling is one of the most accepted methods to bring back plastics into the loop. Polyhydroxybutyrates (PHBs) are biobased and biodegradable in nature with promising properties and varied applications in the market. This study focuses on their potential for mechanical recycling by multiple extrusion cycles (E1–E5) and multi-faceted characterization of the virgin (V) and reprocessed materials from E1 to E5. The behavior is compared to polypropylene (PP) as a reference with a similar property profile, which has also been reprocessed five times. The thermal properties of both series showed a stable melting point and thermal decomposition temperature from thermal analyses (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)). However, a steady increase in the degree of crystallinity was observed which could counterbalance the decrease in molecular weight due to repeated extrusion measured by gel permeation chromatography and resulted in similar values of tensile strength across the cycles. The strain at break was impacted after the first extrusion, but no significant change was observed thereafter; the same was observed for impact strength. Even in scanning electron microscopy (SEM) images, virgin and E5 samples appeared similar, showing the stability of morphological characteristics. Fourier transform infrared spectroscopy (FTIR) results revealed that no new groups are being formed even on repeated processing. The deviation between the PHB and PP series was more predominant in the melt mass flow rate (MFR) and rheology studies. There was a drastic drop in the MFR values in PHB from virgin to E5, whereas not much difference was observed for PP throughout the cycles. This observation was corroborated by frequency sweeps conducted with the parallel plate method. The viscosity dropped from virgin to E1 and E2, but from E3 to E5 it presented similar values. This was in contrast to PP, where all the samples from virgin to E5 had the same values of viscosity. This paper highlights the possibilities of mechanical recycling of PHB and explains why future work with the addition of virgin material and other additives is an area to be explored.
Investigation of Dielectric, Mechanical, and Thermal Properties of Epoxy Composites Embedded with Quartz Fibers
Authors: Haider Imran , Gul Iftikhar Hussain , Faraz Muhammad Iftikhar , Aziz Shahid , Jaffery Syed Husain Imran , Khan Muhammad Ali , Jung Dong-Won
Published: October 2023

Polymer matrix wave transparent composites are used in a variety of high-speed communication applications. One of the applications of these involves making protective enclosures for antennas of microwave towers, air vehicles, weather radars, and underwater communication devices. Material performance, structural, thermal, and mechanical degradation are matters of concern as advanced wireless communication needs robust materials for radomes that can withstand mechanical and thermal stresses. These polymer composite radomes are installed externally on antennas and are exposed directly to ambient as well as severe conditions. In this research, epoxy resin was reinforced with a small amount of quartz fibers to yield an improved composite radome material compared to a pure epoxy composite with better thermal and mechanical properties. FTIR spectra, SEM morphology, dielectric constant (Ɛr) and dielectric loss (δ), thermal degradation (weight loss), and mechanical properties were determined. Compared to pure epoxy, the lowest values of Ɛr and δ were 3.26 and 0.021 with 30 wt.% quartz fibers in the composite, while 40% less weight loss was observed which shows its better thermal stability. The mechanical characteristics encompassing tensile and bending strength were improved by 42.8% and 48.3%. In high-speed communication applications, compared to a pure epoxy composite, adding only a small quantity of quartz fiber can improve the composite material’s dielectric performance, durability, and thermal and mechanical strength.
Silica NPs in PLA-Based Electrospun Nanofibrous Non-Woven Protective Fabrics with Dual Hydrophilicity/Hydrophobicity, Breathability, and Thermal Insulation Characteristics for Individuals with Disabilities
Authors: Aijaz Muhammad Omer , Karim Mohammad Rezaul , Alnaser Ibrahim A. , Siddiqui Md Irfanul Haque , Assaifan Abdulaziz K.
Published: October 2023

A perfect protective fabric for handicapped individuals must be lightweight, waterproof, breathable, and able to absorb water. We present a multifunctional protective fabric in which one side is hydrophobic based on the intrinsic hydrophobic biopolymer polylactic acid (PLA) to keep the disabled person from getting wet, while the other side is super-hydrophilic due to embedded silica nanoparticles (NPs) to keep the disabled person safe from a sudden spill of water or other beverage on their skin or clothes. The porosity of the electrospun nanofibrous structure allows the fabric to be breathable, and the silica NPs play an important role as a perfect infrared reflector to keep the person’s clothing cool on warm days. Adding white NPs, such as silicon dioxide, onto or into the textile fibers is an effective method for producing thermally insulated materials. Due to their ability to efficiently block UV light, NPs in a network keep the body cool. Such a multifunctional fabric might be ideal for adult bibs and aprons, outdoor clothing, and other amenities for individuals with disabilities.
Pressure Swing Adsorption Plant for the Recovery and Production of Biohydrogen: Optimization and Control
Authors: Brizuela-Mendoza Jorge A. , Sorcia-Vázquez Felipe D. J. , Rumbo-Morales Jesse Y. , Ortiz-Torres Gerardo , Torres-Cantero Carlos Alberto , Juárez Mario A. , Zatarain Omar , Ramos-Martinez Moises , Sarmiento-Bustos Estela , Rodríguez-Cerda Julio C. , Mixteco-Sánchez Juan Carlos , Buenabad-Arias Hector Miguel
Published: October 2023

New biofuels are in demand and necessary to address the climate problems caused by the gases generated by fossil fuels. Biohydrogen, which is a clean biofuel with great potential in terms of energy capacity, is currently impacting our world. However, to produce biohydrogen, it is necessary to implement novel processes, such as Pressure Swing Adsorption (PSA), which raise the purity of biohydrogen to 99.99% and obtain a recovery above 50% using lower energy efficiency. This paper presents a PSA plant to produce biohydrogen and obtain a biofuel meeting international criteria. It focuses on implementing controllers on the PSA plant to maintain the desired purity stable and attenuate disturbances that affect the productivity, recovery, and energy efficiency generated by the biohydrogen-producing PSA plant. Several rigorous tests were carried out to observe the purity behavior in the face of changes in trajectories and combined perturbations by considering a discrete observer-based LQR controller compared with a discrete PID control system. The PSA process controller is designed from a simplified model, evaluating its performance on the real nonlinear plant considering perturbations using specialized software. The results are compared with a conventional PID controller, giving rise to a significant contribution related to a biohydrogen purity stable (above 0.99 in molar fraction) in the presence of disturbances and achieving a recovery of 55% to 60% using an energy efficiency of 0.99% to 7.25%.
Investigating the Storm Surge and Flooding in Shenzhen City, China
Authors: Bai Peng , Wu Liangchao , Chen Zhoujie , Xu Jianjun , Li Bo , Li Peiliang
Published: October 2023

Tropical cyclones affecting Shenzhen city have shown a remarkable tendency to increase in both intensity and quantity, highlighting the urgency of accurate forecasts of storm surges and flooding for effective planning and mitigation. Utilizing satellite and field observations together with the advanced high-resolution baroclinic wave–current model (SCHISM), a comprehensive investigation aimed at storm surge and flooding in Shenzhen was conducted. Statistical work of historical tropical cyclones revealed that Shenzhen was most vulnerable to cyclones propagating from the southeast toward the northwest and passing Shenzhen down the Pearl River Estuary. Thus, a representative, i.e., super typhoon Hato (2017), was selected for further study. Validations of numerical results suggested satisfactory model performance in mapping the wave, tide, and surge processes. Remarkable differences in spatiotemporal distribution and intensity of storm surge and flooding were found along the Shenzhen coast, which was dominated by the propagation of far-field surge and tidal waves, cooperation between wind direction and coastline orientation, estuary morphology, and the land terrain. Intervention of wave–current interaction improved the simulation of the surge and flooding and triggered an earlier occurrence time of the maximum surge in specific areas. The Pearl River discharge significantly elevated the sea level height inside the estuary and contributed to a more severe surge. Given the extremely complicated river networks and huge freshwater flux of Pearl River and the increasing trend of concurrent heavy precipitation of tropical cyclones, future investigations on compound flooding were suggested.
Effects of Irrigation Projects on the Classification of Yellow River Terrace Landslides and their Failure Modes: A Case Study of Heitai Terrace
Authors: Zhang Zonglin , Zeng Runqiang , Zhao Shufen , Meng Xingmin , Ma Jianhua , Yin Hailong , Long Zhao
Published: October 2023

The study of the classification and failure modes of Yellow River terrace landslides under the influence of irrigation projects is of key importance to alleviate the paradox between the rapid evolution of terrace landscapes caused by landslides and the survival of local residents. However, such studies remain controversial, despite it being widely recognized that a rise in groundwater level caused by irrigation is a key factor associated with landslide failure modes. In this paper, we take the Heitai terrace as a case study. Using aerial images and field investigations, we classify landslides in the Heitai loess layer into type A landslides (not related to groundwater) and type B1 and B2 landslides (related to groundwater). We analyze the failure modes and disaster-causing characteristics of each type of landslide, and our results indicate that the attenuation in soil strength is a key factor common to both type A and type B landslides, based on which type A landslides with small volume and short sliding distance are able to block the previous spring discharge, causing a rise in localized groundwater, which further contributes to type B landslides; the location of previous type B1 landslides with a large volume and long sliding distance and type A landslides may be more susceptible to type B2 landslides with a small volume and short sliding distance, where there are low confining pressures during the lower soil shear process. Therefore, we believe that the inevitable interaction effects between the failure modes of landslides during landslide evolution, which govern the geomorphological evolution of the Heitai terrace, are unavoidable. Combining these data with numerical analyses, we further demonstrate that a rise in groundwater level and discontinuous attenuation of soil strength caused by changes in soil properties during irrigation together control terrace landslides and their failure modes. From the results of interferometric synthetic aperture radar time-series monitoring of Yellow River terrace activity with and without irrigation projects, and electrical resistivity tomography groundwater detection, we conclude that in the future, Heitai terrace will continue to experience a high intensity of landslide activity, and conditions for the most catastrophic type of landslide (type B1) will remain, including the high localized groundwater caused by previous landslides, and the discontinuous attenuation of soil strength caused by the deterioration in soil properties. In this context, we believe that slope-cutting engineering will be one of the most economical means to achieve future landslide-type transformation on the Heitai terrace; this will mitigate the process of geomorphological evolution and improve the human living environment.
Hyperspectral Prediction Model of Nitrogen Content in Citrus Leaves Based on the CEEMDAN–SR Algorithm
Authors: Gao Changlun , Tang Ting , Wu Weibin , Zhang Fangren , Luo Yuanqiang , Wu Weihao , Yao Beihuo , Li Jiehao
Published: October 2023

Nitrogen content is one of the essential elements in citrus leaves (CL), and many studies have been conducted to determine the nutrient content in CL using hyperspectral technology. To address the key problem that the conventional spectral data-denoising algorithms directly discard high-frequency signals, resulting in missing effective signals, this study proposes a denoising preprocessing algorithm, complete ensemble empirical mode decomposition with adaptive noise joint sparse representation (CEEMDAN–SR), for CL hyperspectral data. For this purpose, 225 sets of fresh CL were collected at the Institute of Fruit Tree Research of the Guangdong Academy of Agricultural Sciences, to measure their elemental nitrogen content and the corresponding hyperspectral data. First, the spectral data were preprocessed using CEEMDAN–SR, Stein’s unbiased risk estimate and the linear expansion of thresholds (SURE–LET), sparse representation (SR), Savitzky–Golay (SG), and the first derivative (FD). Second, feature extraction was carried out using principal component analysis (PCA), uninformative variables elimination (UVE), and the competitive adaptive re-weighted sampling (CARS) algorithm. Finally, partial least squares regression (PLSR), support vector regression (SVR), random forest (RF), and Gaussian process regression (GPR) were used to construct a CL nitrogen prediction model. The results showed that most of the prediction models preprocessed using the CEEMDAN–SR algorithm had better accuracy and robustness. The prediction models based on CEEMDAN–SR preprocessing, PCA feature extraction, and GPR modeling had an R2 of 0.944, NRMSE of 0.057, and RPD of 4.219. The study showed that the CEEMDAN–SR algorithm can be effectively used to denoise CL hyperspectral data and reduce the loss of effective information. The prediction model using the CEEMDAN–SR+PCA+GPR algorithm could accurately obtain the nitrogen content of CL and provide a reference for the accurate fertilization of citrus trees.
A Multiple-False-Target ISAR Shape Deception Jamming Method Based on Improved Template Multiplication Modulated Time-Delay Algorithm and Sub-Nyquist Sampling
Authors: Liu Ying-Xi , Zhang Qun , Xiong Shi-Chao , Wang Hao-Bo , Yuan Hang , Luo Ying
Published: October 2023

In recent decades, the deception jamming approach based on digital radio frequency memory (DRFM) for inverse synthetic aperture radar (ISAR) has been a well-researched topic. Various types of jamming signals based on interrupted-sampling repeater jamming (ISRJ) can induce one-dimensional multiple high-resolution range profile (HRRP) false targets or two-dimensional realistic multiple ISAR false targets for deception. However, these existing methods generate false targets that are identical to the real target. The ISRJ false target also generates a main false target whose energy is much higher than other sub-false targets. Thus, it is easy to discover that the radar has suffered jamming. In order to generate better, more confusing jamming signals, this paper proposes a jamming method based on sub-Nyquist sampling jamming to induce realistic, multiple false targets on ISAR images. It improves a template multiplication modulated time-delay method to eliminate and add scatterers on the selected false target to change its ISAR shape. The frequency-shift parameters of the template jamming signal are analyzed and derived in detail for eliminating and adding scatterers at the specified location. Thus, multiple false targets with different ISAR shapes and similar energy are generated, which can create better deception effects. Meanwhile, this method can adjust the number of false targets and the location of changed-shape false targets. Furthermore, the resolution of the false target can adaptively change with the radar pulse width and the accumulated pulse number. The simulation results show that the proposed deception jamming strategy works.
Technical-Economic Analysis of Energy Efficiency Solutions for the Industrial Steam System of a Natural Gas Processing Plant
Authors: Salimi Mohsen , Amidpour Majid , Moradi Mohammad Ali , Hajivand Marjan , Siahkamari Ebrahim , Shams Mehrzad
Published: October 2023

Steam, which is primarily employed as a heat transfer medium in process plants, is one of the most widely utilized energy carriers in the industrial sector. One of the factors that affects the cost of steam is how well the condensate collection, steam supply, and return systems of industrial steam systems perform. In a case study, the steam systems of a natural gas processing plant were simulated. The amount of demineralized water loss and, consequently, the identification of various solutions to improve the system were analyzed. The whole steam system was simulated using the MEASUR software platform (v 1.2), and by placing the operational information of the steam system, it was possible to create a baseline for the system, model saving solutions, and finally, provide a technical and economic evaluation of the solutions. Due to the high loss of steam condensate in the SRU steam system (more than 3000 kg per hour), solutions to improve the energy efficiency of the SRU steam system in the form of a maximum recovery of steam condensate (replacement of defective steam traps, redesign of the low-pressure condensate collection network, and high-pressure waste condensate collection) were evaluated with two price assumptions of current energy prices and real prices (the energy saving value of one cubic meter of natural gas is equal to 13 cents). The results show that, for current prices, the investment return period will be between 11.8 and 3.8 months. Moreover, in the main steam system of the refinery (unit 9200), there are three solutions: replacing and repairing defective steam traps, installing an expansion turbine instead of a steam pressure relief valve (PRV), and other solutions (including increasing boiler efficiency, automatic control of the boiler, and energy recovery boiler blowdown) under two price assumptions, the current and real prices of natural gas and demineralized water, were evaluated, and the modeling results show that the investment return period for each of the above solutions at the current prices is 10.2, 186, and 13.3, respectively. The investment return period is based on assuming real fuel and BFW prices are equal to 2.0, 37.6, and 1.7, respectively.