bluuebunny/crossref_metadata_2025 huggingface dataset:
Bending Fracture of Different Zirconia-Based Bioceramics for Dental Applications: A Comparative Study
Authors: Fischer Peter , Barbu Horia Mihail , Fischer Caroline Adela Ingrid , Pantea Mihaela , Baciu Florin , Vranceanu Diana Maria , Cotrut Cosmin Mihai , Spinu Tudor Claudiu
Published: November 2021

The fabrication of fixed dental prostheses using aesthetic materials has become routine in today’s dentistry. In the present study, three-unit full zirconia fixed prosthetic restorations obtained by computer-aided design/computer-aided manufacturing (CAD/CAM) technology were tested by bending trials. The prostheses were intended to replace the first mandibular left molar and were manufactured from four different types of zirconia bioceramics (KatanaTM Zirconia HTML and KatanaTM Zirconia STML/Kuraray Noritake Dental Inc.; NOVAZir® Fusion float® ml/NOVADENT/Dentaltechnik; and 3D PRO Zirconia/Bloomden Bioceramics). In total, sixteen samples were manufactured—four samples per zirconia material. Additionally, the morphology, grain size area distribution, and elemental composition were analyzed in parallelepiped samples made from the selected types of zirconia in three different areas, noted as the upper, middle, and lower areas. The scanning electron microscope (SEM) analysis highlighted that the grain size area varies with respect to the researched area and the type of material. Defects such as microcracks and pores were also noted to a smaller extent. In terms of grain size area, it was observed that most of the particles in all samples were under 0.5 μm2, while the chemical composition of the investigated materials did not vary significantly. The results obtained after performing the bending tests showed that a zirconia material with fewer structural defects and an increased percentage of grain size area under 0.5 µm2, ranging from ~44% in the upper area to ~74% in the lower area, exhibited enhanced mechanical behavior. Overall, the resulting values of all investigated parameters confirm that the tested materials are suitable for clinical use.
Determination of Friction Performance of High Friction Surface Treatment Based on Alternative Macrotexture Metric
Authors: Zhao Hua , Wei Fulu , Wang Ce , Li Shuo , Shan Jie
Published: November 2021

Surface friction is currently the most common metric for evaluating the performance of high friction surface treatment (HFST). However, friction test methods such as the locked wheel skid tester (LWST) commonly provide a spot measurement. Large variations may arise in the LWST testing on curves. Based on 21 actual HFST projects, a study was performed to use a macrotexture metric, i.e., the mean profile depth (MPD) to evaluate HFST’s performance and improve its quality control (QC)/quality assurance (QA) procedures. The material properties were presented to understand the aspects of HFST. The method for calculating MPD was modified to account for the variations of macrotexture measurements. A vehicle-based test system was utilized to measure MPD periodically over an 18-month period since HFST installation. Statistical analysis was performed on the MPD measurements to identify the effects of influencing factors. Compared with the friction from LWST, MPD was equally effective in evaluating HFST performance. However, the use of MPD eliminated the errors as arisen in LWST testing and made it possible to detect surface distresses, including aggregate loss, delamination, and cracking. The expected overall MPD may be calculated by combining the MPD measurements made three months after installation at different HFST sites and used as a metric for evaluating HFST performance and QC/QA.
Recent Progress in the Application of Hydroxyapatite for the Adsorption of Heavy Metals from Water Matrices
Authors: Brazdis Roxana Ioana , Fierascu Irina , Avramescu Sorin Marius , Fierascu Radu Claudiu
Published: November 2021

Wastewater treatment remains a critical issue globally, despite various technological advancements and breakthroughs. The study of different materials and technologies gained new valences in the last years, in order to obtain cheap and efficient processes, to obtain a cleaner environment for future generations. In this context, the present review paper presents the new achievements in the materials domain with highlights on apatitic materials used for decontamination of water loaded with heavy metals. The main goal of this review is to present the adsorptive removal of heavy metals using hydroxyapatite-based adsorbents, offering a general overview regarding the recent progress in this particular area. Developing the current review, an attempt has been made to give appropriate recognition to the most recent data regarding the synthesis methods and targeted pollutants, including important information regarding the synthesis methods and precursors, morphological characteristics of the adsorbent materials and effectiveness of processes.
Mussel-Inspired Carboxymethyl Chitosan Hydrogel Coating of Titanium Alloy with Antibacterial and Bioactive Properties
Authors: Ren Yanru , Qin Xiaoyan , Barbeck Mike , Hou Yi , Xu Haijun , Liu Luo , Liu Chaoyong
Published: November 2021

Infection-related titanium implant failure rates remain exceedingly high in the clinic. Functional surface coating represents a very promising strategy to improve the antibacterial and bioactive properties of titanium alloy implants. Here, we describe a novel bioactive surface coating that consists of a mussel-inspired carboxymethyl chitosan hydrogel loaded with silver nanoparticles (AgNPs) to enhance the bioactive properties of the titanium alloy. The preparation of hydrogel is based on gallic acid grafted carboxymethyl chitosan (CMCS-GA) catalyzed by DMTMM (4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride). To build a firm bonding between the hydrogel and titanium alloy plate, a polydopamine layer was introduced onto the surface of the titanium alloy. With HRP/H2O2 catalysis, CMCS-GA can simply form a firm gel layer on the titanium alloy plate through the catechol groups. The surface properties of titanium alloy were characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and water contact angle. Silver nanoparticles were loaded into the gel layer by in situ reduction to enhance the antibacterial properties. In vitro antibacterial and cell viability experiments showed that the AgNPs-loaded Ti-gel possesses excellent antibacterial properties and did not affect the proliferation of rabbit mesenchymal stem cells (MSCs).
Characterization of the Vibration and Strain Energy Density of a Nanobeam under Two-Temperature Generalized Thermoelasticity with Fractional-Order Strain Theory
Authors: Alharthi Hamzah Abdulrahman
Published: November 2021

In this work, fractional-order strain theory was applied to construct a novel model that introduces a thermal analysis of a thermoelastic, isotropic, and homogeneous nanobeam. Under supported conditions of fixed aspect ratios, a two-temperature generalized thermoelasticity theory based on one relaxation time was used. The governing differential equations were solved using the Laplace transform, and their inversions were found by applying the Tzou technique. The numerical solutions and results for a thermoelastic rectangular silicon nitride nanobeam were validated and supported in the case of ramp-type heating. Graphs were used to present the numerical results. The two-temperature model parameter, beam size, ramp-type heat, and beam thickness all have a substantial influence on all of the investigated functions. Moreover, the parameter of the ramp-type heat might be beneficial for controlling the damping of nanobeam energy.
A Fast Bubble Detection Method in Microtubes Based on Pulsed Ultrasound
Authors: Li Yiqing , Wu Junwu , Fu Leijie , Wang Jinju
Published: November 2021

In the process of biological microfluidic manipulation, the bubbles generated in the tube will seriously reduce the gauging accuracy. This paper introduces an improving method that can estimate the size of microbubbles in real time. Hence, the measurement data of the liquid volume can be modified according to this method. A microbubble detector based on the pulsed-ultrasound method was studied, including the device structure and the working principle. The assessment formula of the microbubbles in the tube was derived from the simulation results, which adopted the two-phase theory. The digital image processing method was applied to fulfill the microbubble calibration. This detection method was applied to measure the microbubbles in the tube and to modify the flow volume in a timely manner. The results of the experiments showed that this method is effective at improving the microflow gauging accuracy.
Impact of O-Acetylation on S. flexneri 1b and 2a O-Antigen Immunogenicity in Mice
Authors: Arato Vanessa , Oldrini Davide , Massai Luisa , Gasperini Gianmarco , Necchi Francesca , Micoli Francesca
Published: November 2021

Shigellosis is a diarrheal disease caused prevalently by Shigella flexneri and S. sonnei and representing a major global health risk, particularly in developing countries. Bacterial O-antigen (OAg) is the primary target of the host immune response and modifications of its oligosaccharide units, including O-acetylation, are responsible for the variability among the circulating S. flexneri serotypes. No vaccines are widely available against shigellosis and the understanding of the immunogenicity induced by the OAg is fundamental for the design of a vaccine that could cover the most prevalent Shigella serotypes. To understand whether a different O-acetylation pattern could influence the immune response elicited by S. flexneri OAg, we employed as a vaccine technology GMMA purified from S. flexneri 2a and 1b strains that were easily engineered to obtain differently O-acetylated OAg. Resulting GMMA were tested in mice, demonstrating not only no major impact of O-acetyl decorations on the immune response elicited by the two OAg against the homologous strains, but also that the O-acetylation of the Rhamnose III residue (O-factor 9), shared among serotypes 1b, 2a and 6, does not induce cross-reactive antibodies against these serotypes. This work contributes to the optimization of vaccine design against Shigella, providing indication about the ability of shared epitopes to elicit broad protection against S. flexneri serotypes and supporting the identification of critical quality attributes of OAg-based vaccines.
Schisandrin B Attenuates Hepatic Stellate Cell Activation and Promotes Apoptosis to Protect against Liver Fibrosis
Authors: Li Zhiman , Zhao Lijuan , Xia Yunshi , Chen Jianbo , Hua Mei , Sun Yinshi
Published: November 2021

The activation of hepatic stellate cells (HSC) plays a key role in the progression of hepatic fibrosis, it is essential to remove activated HSC through apoptosis to reverse hepatic fibrosis. Schisandrin B (Sch B) is the main chemical component of schisandrin lignan, and it has been reported to have good hepatoprotective effects. However, Schisandrin B on HSC apoptosis remains unclear. In our study, we stimulated the HSC-T6 and LX-2 cell lines with TGF-β1 to induce cell activation, and the proliferation and apoptosis of the activated HSC-T6 and LX-2 cells were detected after treatment with different doses of Schisandrin B. Flow cytometry results showed that Sch B significantly reduced the activity of activated HSC-T6 and LX-2 cells and significantly induced apoptosis. In addition, the cleaved-Caspase-3 levels were increased, the Bax activity was increased, and the Bcl-2 expression was decreased in HSC-T6 and LX-2 cells treated with Sch B. Our study showed that Sch B inhibited the TGF-β1-induced activity of hepatic stellate cells by promoting apoptosis.
Cascade Transformations of 1-R-Ethynyl-9,10-anthraquinones with Amidines: Expanding Access to Isoaporphinoid Alkaloids
Authors: Vasilevsky Sergey , Krivenko Ol’ga , Sorokina Irina , Baev Dmitry , Tolstikova Tatyana , Alabugin Igor
Published: November 2021

The interaction of acetamidine and phenylamidine with peri-R-ethynyl-9,10-anthraquinones in refluxing n-butanol leads to the formation of cascade transformations products: addition/elimination/cyclization―2-R-7H-dibenzo[de,h]quinolin-7-ones and(or) 2-R-3-aroyl-7H-dibenzo[de,h]quinolin-7-ones. The anti-inflammatory and antitumor properties of the new 2-R-7H-dibenzo[de,h]quinolin-7-ones were investigated in vivo, in vitro, and in silico. The synthesized compounds exhibit high anti-inflammatory activity at dose 20 mg/kg (intraperitoneal injection) in the models of exudative (histamine-induced) and immunogenic (concanavalin A-induced) inflammation. Molecular docking data demonstrate that quinolinones can potentially intercalate into DNA similarly to the antitumor drug doxorubicin.
Narrow Segment Driven Multistep Magnetization Reversal Process in Sharp Diameter Modulated Fe67Co33 Nanowires
Authors: García Javier , Fernández-Roldán Jose A. , González Roque , Méndez Miguel , Bran Cristina , Vega Víctor , González Silvia , Vázquez Manuel , Prida Víctor M.
Published: November 2021

Magnetic nanomaterials are of great interest due to their potential use in data storage, biotechnology, or spintronic based devices, among others. The control of magnetism at such scale entails complexing the nanostructures by tuning their composition, shape, sizes, or even several of these properties at the same time, in order to search for new phenomena or optimize their performance. An interesting pathway to affect the dynamics of the magnetization reversal in ferromagnetic nanostructures is to introduce geometrical modulations to act as nucleation or pinning centers for the magnetic domain walls. Considering the case of 3D magnetic nanowires, the modulation of the diameter across their length can produce such effect as long as the segment diameter transition is sharp enough. In this work, diameter modulated Fe67Co33 ferromagnetic nanowires have been grown into the prepatterned diameter modulated nanopores of anodized Al2O3 membranes. Their morphological and compositional characterization was carried out by electron-based microscopy, while their magnetic behavior has been measured on both the nanowire array as well as for individual bisegmented nanowires after being released from the alumina template. The magnetic hysteresis loops, together with the evaluation of First Order Reversal Curve diagrams, point out that the magnetization reversal of the bisegmented FeCo nanowires is carried out in two steps. These two stages are interpreted by micromagnetic modeling, where a shell of the wide segment reverses its magnetization first, followed by the reversal of its core together with the narrow segment of the nanowire at once.
Fluorescence Based Comparative Sensing Behavior of the Nano-Composites of SiO2 and TiO2 towards Toxic Hg2+ Ions
Authors: Ekta  , Utreja Divya
Published: November 2021

We have synthesized sulfonamide based nano-composites of SiO2 and TiO2 for selective and sensitive determination of toxic metal ion Hg2+ in aqueous medium. Nano-composites (11) and (12) were morphologically characterized with FT-IR, solid state NMR, UV-vis, FE SEM, TEM, EDX, BET, pXRD and elemental analysis. The comparative sensing behavior, pH effect and sensor concentrations were carried out with fluorescence signaling on spectrofluorometer and nano-composites (11) and (12), both were evaluated as “turn-on” fluorescence detector for the toxic Hg2+ ions. The LODs were calculated to be 41.2 and 18.8 nM, respectively of nano-composites (11) and (12). The detection limit of TiO2 based nano-composites was found comparatively lower than the SiO2 based nano-composites.
Surface Properties and Adherence of Bradyrhizobium diazoefficiens to Glycine max Roots Are Altered When Grown in Soil Extracted Nutrients
Authors: Sandhu Armaan Kaur , Subramanian Senthil , Brözel Volker S.
Published: November 2021

Soybean roots are colonized and nodulated by multiple strains of compatible nitrogen-fixing rhizobia primarily belonging to the Genus Bradyrhizobium. Motility towards the root and attachment to root hairs are key determinants of competitive colonization and subsequent nodulation. Bacterial surface properties and motility are known to vary with chemical composition of the culture medium, and root adhesion and nodulation occur in a soil environment rather than laboratory medium. We asked whether the nodulation-promoting factors motility, surface hydrophobicity and surface adhesion of Bradyrhizobium are affected by growth in a soil nutrient environment. B. diazoefficiens USDA 110, 126, 3384, and B. elkanii USDA 26 were grown in mineral salt medium with peptone, yeast extract and arabinose (PSY), and in a soil extracted soluble organic matter (SESOM) medium. Surface hydrophobicity was determined by partitioning into hydrocarbon, motility by transition through soft agar, and surface-exposed saccharides by lectin profiling, followed by biofilm formation and soybean root adhesion capacity of populations. SESOM-grown populations were generally less motile and more hydrophobic. They bound fewer lectins than PSY-grown populations, indicating a simpler surface saccharide profile. SESOM populations of USDA 110 did not form detectable biofilm, but showed increased binding to soy roots. Our results indicate that growth in a soil environment impacts surface properties, motility, and subsequent soy root adhesion propensity. Hence, evaluation of Bradyrhizobium for nodulation efficiency should be performed using soil from the specific field where the soybeans are to be planted, rather than laboratory culture media.
Effect of Dapagliflozin and Magnesium Supplementation on Renal Magnesium Handling and Magnesium Homeostasis in Metabolic Syndrome
Authors: Ng Hwee-Yeong , Kuo Wei-Hung , Tain You-Lin , Leung Foong-Fah , Lee Wen-Chin , Lee Chien-Te
Published: November 2021

The prevalence of metabolic syndrome (MetS) is increasing, and patients with MetS are at an increased risk of cardiovascular disease and diabetes. There is a close link between hypomagnesemia and MetS. Administration of sodium-glucose transporter 2 (SGLT2) inhibitors has been reported to increase serum magnesium levels in patients with diabetes. We investigated the alterations in renal magnesium handling in an animal model of MetS and analyzed the effects of SGLT2 inhibitors. Adult rats were fed a fructose-rich diet to induce MetS in the first 3 months and were then treated with either dapagliflozin or magnesium sulfate-containing drinking water for another 3 months. Fructose-fed animals had increased insulin resistance, hypomagnesemia, and decreased urinary magnesium excretion. Dapagliflozin treatment improved insulin resistance by decreasing glucose and insulin levels, increased serum magnesium levels, and reduced urinary magnesium excretion. Serum vitamin D and parathyroid hormone levels were decreased in fructose-fed animals, and the levels remained low despite dapagliflozin and magnesium supplementation. In the kidney, claudin-16, TRPM6/7, and FXDY expression was increased in fructose-fed animals. Dapagliflozin increased intracellular magnesium concentration, and this effect was inhibited by TRPM6 blockade and the EGFR antagonist. We concluded that high fructose intake combined with a low-magnesium diet induced MetS and hypomagnesemia. Both dapagliflozin and magnesium sulfate supplementation improved the features of MetS and increased serum magnesium levels. Expression levels of magnesium transporters such as claudin-16, TRPM6/7, and FXYD2 were increased in fructose-fed animals and in those administered dapagliflozin and magnesium sulfate. Dapagliflozin enhances TRPM6-mediated trans-epithelial magnesium transport in renal tubule cells.
Effect of a Remotely Delivered Weight Loss Intervention in Early-Stage Breast Cancer: Randomized Controlled Trial
Authors: Reeves Marina M. , Terranova Caroline O. , Winkler Elisabeth A. H. , McCarthy Nicole , Hickman Ingrid J. , Ware Robert S. , Lawler Sheleigh P. , Eakin Elizabeth G. , Demark-Wahnefried Wendy
Published: November 2021

Limited evidence exists on the effects of weight loss on chronic disease risk and patient-reported outcomes in breast cancer survivors. Breast cancer survivors (stage I–III; body mass index 25–45 kg/m2) were randomized to a 12-month, remotely delivered (22 telephone calls, mailed material, optional text messages) weight loss (diet and physical activity) intervention (n = 79) or usual care (n = 80). Weight loss (primary outcome), body composition, metabolic syndrome risk score and components, quality of life, fatigue, musculoskeletal pain, menopausal symptoms, fear of recurrence, and body image were assessed at baseline, 6 months, 12 months (primary endpoint), and 18 months. Participants were 55 ± 9 years and 10.7 ± 5.0 months post-diagnosis; retention was 81.8% (12 months) and 80.5% (18 months). At 12-months, intervention participants had significantly greater improvements in weight (−4.5% [95%CI: −6.5, −2.5]; p < 0.001), fat mass (−3.3 kg [−4.8, −1.9]; p < 0.001), metabolic syndrome risk score (−0.19 [−0.32, −0.05]; p = 0.006), waist circumference (−3.2 cm [−5.5, −0.9]; p = 0.007), fasting plasma glucose (−0.23 mmol/L [−0.44, −0.02]; p = 0.032), physical quality of life (2.7 [0.7, 4.6]; p = 0.007; Cohen’s effect size (d) = 0.40), musculoskeletal pain (−0.5 [−0.8, −0.2]; p = 0.003; d = 0.49), and body image (−0.2 [−0.4, −0.0]; p = 0.030; d = 0.31) than usual care. At 18 months, effects on weight, adiposity, and metabolic syndrome risk scores were sustained; however, significant reductions in lean mass were observed (−1.1 kg [−1.7, −0.4]; p < 0.001). This intervention led to sustained improvements in adiposity and metabolic syndrome risk.
N-3 Polyunsaturated Fatty Acids Ameliorate Neurobehavioral Outcomes Post-Mild Traumatic Brain Injury in the Fat-1 Mouse Model
Authors: Lecques Jessica-Dominique , Kerr Brynna J. K. , Hillyer Lyn M. , Kang Jing X. , Robinson Lindsay E. , Ma David W. L.
Published: November 2021

Concussions and mild traumatic brain injury (m-TBI) have been identified as a consequential public health concern because of their potential to cause considerable impairments in physical, cognitive, behavioral, and social functions. Given their prominent structural and functional roles in the brain, n-3 polyunsaturated fatty acids (PUFA) have been identified as a potentially viable prophylactic agent that may ameliorate the deleterious effects of m-TBI on brain function. The purpose of the present pilot study was to investigate the effect of n-3 PUFA on neurologic function using a weight drop injury (WDI) model. Fat-1 mice, capable of synthesizing n-3 PUFA endogenously from n-6 PUFA, and their wild-type (WT) counterparts, were subjected to a mild low-impact WDI on the closed cranium, and recovery was evaluated using the neurological severity score (NSS) to assess the motor and neurobehavioral outcomes. In comparison to the WT mice, the fat-1 mice had a significantly (p ≤ 0.05) lower NSS at all time points post-WDI, and significantly greater neurological restoration measured as the time to first movement. Overall, these findings demonstrate the protective effect of n-3 PUFA against mild brain injury.
Genetic Diversity of Genes Controlling Unilateral Incompatibility in Japanese Cultivars of Chinese Cabbage
Authors: Takada Yoshinobu , Mihara Atsuki , He Yuhui , Xie Haolin , Ozaki Yusuke , Nishida Hikari , Hong Seongmin , Lim Yong-Pyo , Takayama Seiji , Suzuki Go , Watanabe Masao
Published: November 2021

In recent years, unilateral incompatibility (UI), which is an incompatibility system for recognizing and rejecting foreign pollen that operates in one direction, has been shown to be closely related to self-incompatibility (SI) in Brassica rapa. The stigma- and pollen-side recognition factors (SUI1 and PUI1, respectively) of this UI are similar to those of SI (stigma-side SRK and pollen-side SP11), indicating that SUI1 and PUI1 interact with each other and cause pollen-pistil incompatibility only when a specific genotype is pollinated. To clarify the genetic diversity of SUI1 and PUI1 in Japanese B. rapa, here we investigated the UI phenotype and the SUI1/PUI1 sequences in Japanese commercial varieties of Chinese cabbage. The present study showed that multiple copies of nonfunctional PUI1 were located within and in the vicinity of the UI locus region, and that the functional SUI1 was highly conserved in Chinese cabbage. In addition, we found a novel nonfunctional SUI1 allele with a dominant negative effect on the functional SUI1 allele in the heterozygote.
Substituted Organotin Complexes of 4-Methoxybenzoic Acid for Reduction of Poly(vinyl Chloride) Photodegradation
Authors: Hadi Angham G. , Baqir Sadiq J. , Ahmed Dina S. , El-Hiti Gamal A. , Hashim Hassan , Ahmed Ahmed , Kariuki Benson M. , Yousif Emad
Published: November 2021

Poly(vinyl chloride) suffers from degradation through oxidation and decomposition when exposed to radiation and high temperatures. Stabilizers are added to polymeric materials to inhibit their degradation and enable their use for a longer duration in harsh environments. The design of new additives to stabilize poly(vinyl chloride) is therefore desirable. The current study includes the synthesis of new tin complexes of 4-methoxybenzoic acid and investigates their potential as photostabilizers for poly(vinyl chloride). The reaction of 4-methoxybenzoic acid and substituted tin chlorides gave the corresponding substituted tin complexes in good yields. The structures of the complexes were confirmed using analytical and spectroscopic methods. Poly(vinyl chloride) was doped with a small quantity (0.5%) of the tin complexes and homogenous thin films were made. The effects of the additives on the stability of the polymeric material on irradiation with ultraviolet light were assessed using different methods. Weight loss, production of small polymeric fragments, and drops in molecular weight were lower in the presence of the additives. The surface of poly(vinyl chloride), after irradiation, showed less damage in the films containing additives. The additives, in particular those containing aromatic (phenyl groups) substitutes, inhibited the photodegradation of polymeric films significantly. Such additives act as efficient ultraviolet absorbers, peroxide quenchers, and hydrogen chloride scavengers.
Effective Young’s Modulus Estimation of Natural Fibers through Micromechanical Models: The Case of Henequen Fibers Reinforced-PP Composites
Authors: Serra-Parareda Ferran , Vilaseca Fabiola , Aguado Roberto , Espinach Francesc X. , Tarrés Quim , Delgado-Aguilar Marc
Published: November 2021

In this study, Young’s modulus of henequen fibers was estimated through micromechanical modeling of polypropylene (PP)-based composites, and further corroborated through a single filament tensile test after applying a correction method. PP and henequen strands, chopped to 1 mm length, were mixed in the presence of maleic anhydride grafted polypropylene (MAPP). A 4 wt.% of MAPP showed an effective enhancement of the interfacial adhesion. The composites were mold-injected into dog-bone specimens and tensile tested. The Young’s modulus of the composites increased steadily and linearly up to 50 wt.% of fiber content from 1.5 to 6.4 GPa, corresponding to a 327% increase. Certainly, henequen fibers showed a comparable stiffening capacity of PP composites than glass fibers. The intrinsic Young’s modulus of the fibers was predicted through well established models such as Hirsch or Tsai-Pagano, yielding average values of 30.5 and 34.6 GPa, respectively. The single filament test performed to henequen strands resulted in values between 16 and 27 GPa depending on the gauge length, although, after applying a correction method, a Young’s modulus of 33.3 GPa was obtained. Overall, the present work presents the great potential for henequen fibers as PP reinforcement. Moreover, relationships between micromechanics models and filament testing to estimate Young’s modulus of the fibers were explored.
Process Intensification in Photocatalytic Decomposition of Formic Acid over a TiO2 Catalyst by Forced Periodic Modulation of Concentration, Temperature, Flowrate and Light Intensity
Authors: Ellwood Thomas , Živković Luka A. , Denissenko Petr , Abiev Rufat Sh. , Rebrov Evgeny V. , Petkovska Menka
Published: November 2021

The effect of forced periodic modulation of several input parameters on the rate of photocatalytic decomposition of formic acid over a TiO2 thin film catalyst has been investigated in a continuously stirred tank reactor. The kinetic model was adopted based on the literature and it includes acid adsorption, desorption steps, the formation of photocatalytic active sites and decomposition of the adsorbed species over the active titania sites. A reactor model was developed that describes mass balances of reactive species. The analysis of the reactor was performed with a computer-aided nonlinear frequency response method. Initially, the effect of amplitude and frequency of four input parameters (flowrate, acid concentration, temperature and light intensity) were studied. All single inputs provided only a minor improvement, which did not exceed 4%. However, a modulation of two input parameters, inlet flowrate and the acid molar fraction, considerably improved the acid conversion from 80 to 96%. This is equivalent to a factor of two increase in residence time at steady-state operation at the same temperature and acid concentration.
Automated Low-Cost LED-Based Sun Photometer for City Scale Distributed Measurements
Authors: Garrido Cristobal , Toledo Felipe , Diaz Marcos , Rondanelli Roberto
Published: November 2021

We propose a monochromatic low-cost automatic sun photometer (LoCo-ASP) to perform distributed aerosol optical depth (AOD) measurements at the city scale. This kind of network could fill the gap between current automatic ground instruments—with good temporal resolution and accuracy, but few devices per city and satellite products—with global coverage, but lower temporal resolution and accuracy-. As a first approach, we consider a single equivalent wavelength around 408 nm. The cost of materials for the instrument is around 220 dollars. Moreover, we propose a calibration transfer for a pattern instrument, and estimate the uncertainties for several units and due to the internal differences and the calibration process. We achieve a max MAE of 0.026 for 38 sensors at 408 nm compared with AERONET Cimel; a mean standard deviation of 0.0062 among our entire sensor for measurement and a calibration uncertainty of 0.01. Finally, we perform city-scale measurements to show the dynamics of AOD. Our instrument can measure unsupervised, with an expected error for AOD between 0.02 and 0.03.
A Time-Frequency Joint Time-Delay Difference Estimation Method for Signal Enhancement in the Distorted towed Hydrophone Array
Authors: Zhu Chuanqi , Fang Shiliang , Wu Qisong , An Liang , Luo Xinwei , Cao Hongli
Published: November 2021

To acquire the enhanced underwater ship-radiated noise signal in the presence of array shape distortion in a passive sonar system, the phase difference of the line-spectrum component in ship-radiated noise is often exploited to estimate the time-delay difference for the beamforming-based signal enhancement. However, the time-delay difference estimation performance drastically degrades with decreases of the signal-to-noise ratio (SNR) of the line-spectrum component. Meanwhile, although the time-delay difference estimation performance of the high-frequency line-spectrum components is generally superior to that of the low-frequency one, the phase difference measurements of the high-frequency line-spectrum component often easily encounter the issue of modulus 2π ambiguity. To address the above issues, a novel time-frequency joint time-delay difference estimation method is proposed in this paper. The proposed method establishes a data-driven hidden Markov model with robustness to phase difference ambiguity by fully exploiting the underlying property of slowly changing the time-delay difference over time. Thus, the phase difference measurements available for time-delay difference estimation are extended from that of low-frequency line-spectrum components in a single frame to that of all detected line-spectrum components in multiple frames. By jointly taking advantage of the phase difference measurements in both time and frequency dimensions, the proposed method can acquire enhanced time-delay difference estimates even in a low SNR case. Both simulation and at-sea experimental results have demonstrated the effectiveness of the proposed method.
Vegetation Resilience under Increasing Drought Conditions in Northern Tanzania
Authors: Verhoeve Steye L. , Keijzer Tamara , Kaitila Rehema , Wickama Juma , Sterk Geert
Published: November 2021

East Africa is comprised of many semi-arid lands that are characterized by insufficient rainfall and the frequent occurrence of droughts. Drought, overgrazing and other impacts due to human activity may cause a decline in vegetation cover, which may result in land degradation. This study aimed to assess drought occurrence, vegetation cover changes and vegetation resilience in the Monduli and Longido districts in northern Tanzania. Satellite-derived data of rainfall, temperature and vegetation cover were used. Monthly precipitation (CenTrends v1.0 extended with CHIRPS2.0) and monthly mean temperatures (CRU TS4.03) were collected for the period of 1940–2020. Eight-day maximum value composite data of the normalized difference vegetation index (NDVI) (NOAA CDR—AVHRR) were obtained for the period of 1981–2020. Based on the meteorological data, trends in rainfall, temperature and drought were determined. The NDVI data were used to determine changes in vegetation cover and vegetation resilience related to the occurrence of drought. Rainfall did not significantly change over the period of 1940–2020, but mean monthly temperatures increased by 1.06 °C. The higher temperatures resulted in more frequent and prolonged droughts due to higher potential evapotranspiration rates. Vegetation cover declined by 9.7% between 1981 and 2020, which is lower than reported in several other studies, and most likely caused by the enhanced droughts. Vegetation resilience on the other hand is still high, meaning that a dry season or year resulted in lower vegetation cover, but a quick recovery was observed during the next normal or above-normal rainy season. It is concluded that despite the overall decline in vegetation cover, the changes have not been as dramatic as earlier reported, and that vegetation resilience is good in the study area. However, climate change predictions for the area suggest the occurrence of more droughts, which might lead to further vegetation cover decline and possibly a shift in vegetation species to more drought-prone species.
A Novel 3D Node Deployment Inspired by Dusty Plasma Crystallization in UAV-Assisted Wireless Sensor Network Applications
Authors: Tang Rongxin , Tao Yuhao , Li Jiahao , Hu Zhiming , Yuan Kai , Wu Zhiping , Liu Shiyun , Wang Yuhao
Published: November 2021

With the rapid progress of hardware and software, a wireless sensor network has been widely used in many applications in various fields. However, most discussions for the WSN node deployment mainly concentrated on the two-dimensional plane. In such a case, some large scale applications, such as information detection in deep space or deep sea, will require a good three dimensional (3D) sensor deployment scenario and also attract most scientists’ interests. Excellent deployment algorithms enable sensors to be quickly deployed in designated areas with the help of unmanned aerial vehicles (UAVs). In this paper, for the first time, we present a three dimensional network deployment algorithm inspired by physical dusty plasma crystallization theory in large-scale WSN applications. Four kinds of performance evaluation methods in 3D space, such as the moving distance, the spatial distribution diversion, system coverage rate, and the system utilization are introduced and have been carefully tested.Furthermore, in order to improve the performance of the final deployment, we integrated the system coverage rate and the system utilization to analyze the parameter effects of the Debye length and the node sensing radius. This criterion attempts to find the optimal sensing radius with a fixed Debye length to maximize the sensing range of the sensor network while reducing the system redundancy. The results suggest that our 3D algorithm can quickly complete an overall 3D network deployment and then dynamically adjust parameters to achieve a better distribution. In practical applications, engineers may choose appropriate parameters based on the sensor’s hardware capabilities to achieve a better 3D sensor network deployment. It may be significantly used in some large-scale 3D WSN applications in the near future.
Development and Characterization of Novel Conductive Sensing Fibers for In Vivo Nerve Stimulation
Authors: Richter Bertram , Mace Zachary , Hays Megan , Adhikari Santosh , Pham Huy , Sclabassi Robert , Kolber Benedict , Yerneni Saigopalakrishna , Campbell Phil , Cheng Boyle , Tomycz Nestor , Whiting Donald , Le Trung , Nelson Toby , Averick Saadyah
Published: November 2021

Advancements in electrode technologies to both stimulate and record the central nervous system’s electrical activities are enabling significant improvements in both the understanding and treatment of different neurological diseases. However, the current neural recording and stimulating electrodes are metallic, requiring invasive and damaging methods to interface with neural tissue. These electrodes may also degrade, resulting in additional invasive procedures. Furthermore, metal electrodes may cause nerve damage due to their inherent rigidity. This paper demonstrates that novel electrically conductive organic fibers (ECFs) can be used for direct nerve stimulation. The ECFs were prepared using a standard polyester material as the structural base, with a carbon nanotube ink applied to the surface as the electrical conductor. We report on three experiments: the first one to characterize the conductive properties of the ECFs; the second one to investigate the fiber cytotoxic properties in vitro; and the third one to demonstrate the utility of the ECF for direct nerve stimulation in an in vivo rodent model.
Human Gait Recognition: A Single Stream Optimal Deep Learning Features Fusion
Authors: Saleem Faizan , Khan Muhammad Attique , Alhaisoni Majed , Tariq Usman , Armghan Ammar , Alenezi Fayadh , Choi Jung-In , Kadry Seifedine
Published: November 2021

Human Gait Recognition (HGR) is a biometric technique that has been utilized for security purposes for the last decade. The performance of gait recognition can be influenced by various factors such as wearing clothes, carrying a bag, and the walking surfaces. Furthermore, identification from differing views is a significant difficulty in HGR. Many techniques have been introduced in the literature for HGR using conventional and deep learning techniques. However, the traditional methods are not suitable for large datasets. Therefore, a new framework is proposed for human gait recognition using deep learning and best feature selection. The proposed framework includes data augmentation, feature extraction, feature selection, feature fusion, and classification. In the augmentation step, three flip operations were used. In the feature extraction step, two pre-trained models were employed, Inception-ResNet-V2 and NASNet Mobile. Both models were fine-tuned and trained using transfer learning on the CASIA B gait dataset. The features of the selected deep models were optimized using a modified three-step whale optimization algorithm and the best features were chosen. The selected best features were fused using the modified mean absolute deviation extended serial fusion (MDeSF) approach. Then, the final classification was performed using several classification algorithms. The experimental process was conducted on the entire CASIA B dataset and achieved an average accuracy of 89.0. Comparison with existing techniques showed an improvement in accuracy, recall rate, and computational time.
Integrative Medicine—Acupuncture on Yourself?
Authors: Litscher Gerhard
Published: November 2021

The aim of this editorial is to demonstrate publications on self-acupuncture from both the East (China) and the West and to bring new variants such as self-applied laser medicine into the focus of interest. Self-acupuncture with needles may of course only be carried out according to the applicable laws of the respective country and these are naturally very different. However, important evidence from the studies published so far has not yet been clearly proven. The answer to a question resulting from the editorial, how tradition and innovation in the field of self-acupuncture can be efficiently combined, will have to be proven by future studies.
SPI-Based Hybrid Hidden Markov–GA, ARIMA–GA, and ARIMA–GA–ANN Models for Meteorological Drought Forecasting
Authors: Alquraish Mohammed , Ali. Abuhasel Khaled , S. Alqahtani Abdulrahman , Khadr Mosaad
Published: November 2021

Drought is a severe environmental disaster that results in significant social and economic damage. As such, efficient mitigation plans must rely on precise modeling and forecasting of the phenomenon. This study was designed to enhance drought forecasting through developing and evaluating the applicability of three hybrid models—the hidden Markov model–genetic algorithm (HMM–GA), the auto-regressive integrated moving average–genetic algorithm (ARIMA–GA), and a novel auto-regressive integrated moving average–genetic algorithm–ANN (ARIMA–GA–ANN)—to forecast the standard precipitation index (SPI) in the Bisha Valley, Saudi Arabia. The accuracy of the models was investigated and compared with that of classical HMM and ARIMA based on a performance evaluation and visual inspection. Furthermore, the multi-class Receiver Operating Characteristic-based Area under the Curve (ROC–AUC) was applied to evaluate the ability of the hybrid model to forecast drought events. We used data from 1968 to 2008 to train the models and data from 2009 to 2019 for validation. The performance evaluation results confirmed that the hybrid models provided superior results in forecasting the SPI one month in advance. Furthermore, the results demonstrated that the GA-induced improvement in the HMM forecasts was matched by an approximate 16.40% and 23.46% decrease in the RMSE in the training and testing results, respectively, compared to the classical HMM model. Consequently, the RMSE values of the ARIMA–GA model were reduced by an average of 10.06% and 9.36% for the training and testing processes, respectively. Finally, the ARIMA–GA–ANN, which combined the strengths of the linear stochastic model ARIMA and a non-linear ANN, achieved a greater reduction values in RMSE by an average of 32.82% and 27.47% in comparison with ARIMA in the training and testing phases, respectively. The ROC–AUC results confirmed the capability of the developed models to distinguish between events and non-events with reasonable accuracy, implying the appropriateness of these models as a tool for drought mitigation and warning systems.
Pressurized Liquid Extraction of Polyphenols and Anthocyanins from Saffron Processing Waste with Aqueous Organic Acid Solutions: Comparison with Stirred-Tank and Ultrasound-Assisted Techniques
Authors: Pappas Vasileios M. , Athanasiadis Vassilis , Palaiogiannis Dimitrios , Poulianiti Konstantina , Bozinou Eleni , Lalas Stavros I. , Makris Dimitris P.
Published: November 2021

Fοllow up with our previous study on the extraction of saffron processing waste polyphenols using deep eutectic solvents, the objective of this examination was a comparative evaluation of pressurized liquid extraction (PLE), stirred-tank extraction (STE) and stirred-tank extraction with ultrasonication pretreatment (STE/UP) with respect to the recovery of pigments and antioxidant polyphenols from saffron processing waste. Aqueous solutions of citric and lactic acids at two different concentrations were used as green solvents. The extracts obtained under the specified conditions were analyzed for total pigment and total polyphenol yields as well as for their ferric-reducing power and antiradical activity. Furthermore, each produced extract was analyzed with liquid chromatography–mass spectrometry to profile its analytical polyphenolic composition. In all cases, PLE provided inferior results compared to the two other techniques, producing extracts with lower polyphenolic concentration and weaker antioxidant properties. On the other hand, no specific pattern was detected concerning the effect of ultrasonication, acid type and acid concentration. Hierarchical cluster analysis indicated that stirred-tank extraction with 1% (w/v) lactic acid and ultrasonication pretreatment might be the highest-performing combination, providing extracts with increased polyphenol and pigment concentration; however, it also enhanced antioxidant activity. It was also concluded that the significantly shorter extraction time when using PLE might be an important element in further optimizing the process, buttressing the use of this technique for the establishment of innovative and sustainable-by-design extraction methodologies.
Examination of Extracellular Polymer (EPS) Extraction Methods for Anaerobic Membrane Bioreactor (AnMBR) Biomass
Authors: Galib Mohammed A. , Abbott Timothy , Lee Hyung-Sool
Published: November 2021

Membrane bioreactor fouling is a complex process, which is typically driven by extracellular polymeric substances (EPS), a complex mixture of polysaccharides, proteins, lipids, humic substances, and other intercellular polymers. While much is known about fouling in aerobic membrane reactors, far less is known about fouling in anaerobic membrane bioreactors (AnMBR). Much of this knowledge, including EPS extraction methods, has been extrapolated from aerobic processes and is commonly assumed to be comparable. Therefore, several extraction methods commonly used for aerobic EPS quantification, including ultrasonication, ethylenediaminetetraacetic acid (EDTA), and formaldehyde plus sodium hydroxide (CH2O+NaOH), were evaluated to determine the most suitable extraction method for EPS of anaerobic microorganisms in an AnMBR. To maximize EPS yields, each extraction was performed four times. Experimental results showed that the EDTA method was best for EPS quantification, based on chemical oxygen demand (COD), dissolved organic carbon (DOC), and protein yields: 1.43 mg COD/mg volatile suspended solids (VSS), 0.14 mg DOC/mg VSS, and 0.11 mg proteins/mg VSS. In comparison, the CH2O+NaOH method maximized the extraction of carbohydrates (0.12 mg carbohydrates/mg VSS). However, multiple extraction cycles with EDTA and ultrasonication exhibited lower extracellular adenosine triphosphate (ATP) concentrations compared to CH2O+NaOH extractions, indicating lower levels of released intracellular substances. Successive EPS extractions over four cycles are better able to quantify EPS from anaerobic microorganisms, since a single extraction may not accurately reflect the true levels of EPS contents in AnMBRs, and possibly in other anaerobic processes.