bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and In Vitro-In Vivo Evaluation of Luteolin Loaded Gastroretentive Microsponge for the Eradication of Helicobacter pylori Infections
Authors: Jafar Mohammed , Salahuddin Mohammed , Khan Mohd Sajjad Ahmad , Alshehry Yasir , Alrwaili Nazar Radwan , Alzahrani Yazeed Ali , Imam Syed Sarim , Alshehri Sultan
Published: December 2021

The current study aimed to develop a luteolin gastric floating microsponge for targeting Helicobacter pylori. The microsponge formulations were prepared by a quasi-emulsion method, and then evaluated for various physicochemical variables. The best microsponge was further assessed for drug-polymer interactions, surface morphology, in vivo floating, and in vitro anti H. pylori activity. The formulation which exhibited comparatively good production yield (64.45% ± 0.83), high entrapment efficiency (67.33% ± 3.79), prolonged in vitro floating time (>8 h), and sustained in-vitro drug release was selected as the best microsponge. The SEM study revealed that the best microsponge was spherical in shape and has a porous surface with interconnecting channels. DSC and XRD studies demonstrated the dispersion of luteolin in the polymeric matrix of the microsponge. Ultrasonography confirmed that the best microsponge could in the rat stomach for 4 h. The in vitro MIC results indicate that the anti H. pylori activity of the best microsponge was almost doubled and more sustained compared to pure luteolin. To conclude, it can be said that the developed luteolin gastric floating microsponge could be a better option to effectively eradicate H. pylori infections and the histopathological and pharmacodynamic assessments of our best microsponge can be expected to provide a rewarding outcome.
In Vitro Activity of Monofunctional Pt-II Complex Based on 8-Aminoquinoline against Human Glioblastoma
Authors: Coccè Valentina , Rimoldi Isabella , Facchetti Giorgio , Ciusani Emilio , Alessandri Giulio , Signorini Lucia , Sisto Francesca , Giannì Aldo , Paino Francesca , Pessina Augusto
Published: December 2021

A new cationic Pt(II) complex bearing 8-aminoquinoline as chelating ligand (called Pt-8AQ) was evaluated against two human carcinomas, one mesothelioma, and three glioblastoma cell lines. The in vitro comparison to the clinically approved CisPt showed a minor activity of Pt-8AQ against carcinoma and mesothelioma, whereas a significant activity of Pt-8AQ was observed on the proliferation of the three glioblastoma cell lines (U87-MG IC50 = 3.68 ± 0.69 µM; U373-MG IC50 = 11.53 ± 0.16 µM; U138-MG IC50 = 8.05 ± 0.23 µM) that was higher than that observed with the clinically approved CisPt (U87-MG IC50 = 7.27 + 1.80 µM; U373-MG IC50 = 22.69 ± 0.05 µM; U138-MG IC50 = 32.1 ± 4.44 µM). Cell cycle analysis proved that Pt-8AQ significantly affected the cell cycle pattern by increasing the apoptotic cells represented by the sub G0/G1 region related with a downregulation of p53 and Bcl-2. Moreover, an NMR investigation of Pt-8AQ interaction with 9-EtG, GSH, and Mets7 excluded DNA as the main target, suggesting a novel mechanism of action. Our study demonstrated the high stability of Pt-8AQ after incubation at 37 °C and a significant antineoplastic activity on glioblastomas. These features also make Pt-8AQ a good candidate for developing a new selective advanced cell chemotherapy approach in combination with MSCs.
Pharmacokinetics and Pharmacodynamics of T-Cell Bispecifics in the Tumour Interstitial Fluid
Authors: Eigenmann Miro Julian , Karlsen Tine Veronica , Wagner Marek , Tenstad Olav , Weinzierl Tina , Fauti Tanja , Grimm Hans Peter , Skogstrand Trude , Klein Christian , Sam Johannes , Umana Pablo , Bacac Marina , Wiig Helge , Walz Antje-Christine
Published: December 2021

The goal of this study is to investigate the pharmacokinetics in plasma and tumour interstitial fluid of two T-cell bispecifics (TCBs) with different binding affinities to the tumour target and to assess the subsequent cytokine release in a tumour-bearing humanised mouse model. Pharmacokinetics (PK) as well as cytokine data were collected in humanised mice after iv injection of cibisatamab and CEACAM5-TCB which are binding with different binding affinities to the tumour antigen carcinoembryonic antigen (CEA). The PK data were modelled and coupled to a previously published physiologically based PK model. Corresponding cytokine release profiles were compared to in vitro data. The PK model provided a good fit to the data and precise estimation of key PK parameters. High tumour interstitial concentrations were observed for both TCBs, influenced by their respective target binding affinities. In conclusion, we developed a tailored experimental method to measure PK and cytokine release in plasma and at the site of drug action, namely in the tumour. Integrating those data into a mathematical model enabled to investigate the impact of target affinity on tumour accumulation and can have implications for the PKPD assessment of the therapeutic antibodies.
Polymeric Nanomaterials for Efficient Delivery of Antimicrobial Agents
Authors: Wang Yin , Sun Hui
Published: December 2021

Bacterial infections have threatened the lives of human beings for thousands of years either as major diseases or complications. The elimination of bacterial infections has always occupied a pivotal position in our history. For a long period of time, people were devoted to finding natural antimicrobial agents such as antimicrobial peptides (AMPs), antibiotics and silver ions or synthetic active antimicrobial substances including antimicrobial peptoids, metal oxides and polymers to combat bacterial infections. However, with the emergence of multidrug resistance (MDR), bacterial infection has become one of the most urgent problems worldwide. The efficient delivery of antimicrobial agents to the site of infection precisely is a promising strategy for reducing bacterial resistance. Polymeric nanomaterials have been widely studied as carriers for constructing antimicrobial agent delivery systems and have shown advantages including high biocompatibility, sustained release, targeting and improved bioavailability. In this review, we will highlight recent advances in highly efficient delivery of antimicrobial agents by polymeric nanomaterials such as micelles, vesicles, dendrimers, nanogels, nanofibers and so forth. The biomedical applications of polymeric nanomaterial-based delivery systems in combating MDR bacteria, anti-biofilms, wound healing, tissue engineering and anticancer are demonstrated. Moreover, conclusions and future perspectives are also proposed.
Novel Naproxen Salts with Increased Skin Permeability
Authors: Świątek Ewelina , Ossowicz-Rupniewska Paula , Janus Ewa , Nowak Anna , Sobolewski Peter , Duchnik Wiktoria , Kucharski Łukasz , Klimowicz Adam
Published: December 2021

The paper presents the synthesis, full identification, and characterization of new salts-L-proline alkyl ester naproxenates [ProOR][NAP], where R was a chain from ethyl to butyl (including isopropyl). All obtained compounds were characterized by Nuclear Magnetic Resonance (NMR), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffractometry (XRD), and in vitro dissolution studies. The specific rotation, phase transition temperatures (melting point), and thermal stability were also determined. In addition, their lipophilicity, permeability, and accumulation in pigskin were determined. Finally, toxicity against mouse L929 fibroblast cells was tested. The obtained naproxen derivatives showed improved solubility and higher absorption of drug molecules by biological membranes. Their lipophilicity was lower and increased with the increase in the alkyl chain of the ester. The derivative with isopropyl ester had the best permeability through pigskin. The use of L-proline isopropyl ester naproxenate increased the permeation of naproxen through the skin almost four-fold. It was also shown that the increase in permeability is not associated with additional risk: all compounds had a similar effect on cell viability as the parent naproxen.
Undoing Wh-Movement: On the Need for Multiple Copies
Authors: Witkoś Jacek
Published: December 2021

This contribution presents an outline of the current scholarly discussion of reconstruction with wh-movement, focussing on the Lebeaux Effect (LE) and wider aspects of reconstruction with wh-movement. It presents empirical problems for both the proposals based on the LE and the novel account of movement and reconstruction based on the notion of Minimal Copy. It points out that particular copies may differ not only in size (i.e., they do or do not include the adjunct as a relative clause or PP) but also in content. It refers to an analysis, where copies left by movement are levelled with copies left by ellipsis and subject to the mechanism of Vehicle Change. An account of reconstruction including multiple copies and Vehicle Change predicts that the structural complexity of the wh-phrase and its distance from the offending c-commanding pronoun (embedding and obviation effects) should contribute to an amelioration of Condition C in addition to the LE.
High-Yield Production of Receptor Binding Domain of SARS-CoV-2 Linked to Bacterial Flagellin in Plants Using Self-Replicating Viral Vector pEff
Authors: Mardanova Eugenia S. , Kotlyarov Roman Y. , Ravin Nikolai V.
Published: December 2021

The development of recombinant vaccines against SARS-CoV-2 is required to eliminate the COVID-19 pandemic. We reported the expression of a recombinant protein Flg-RBD comprising receptor binding domain of SARS-CoV-2 spike glycoprotein (RBD) fused to flagellin of Salmonella typhimurium (Flg), known as mucosal adjuvant, in Nicotiana benthamiana plants. The fusion protein, targeted to the cytosol, was transiently expressed using the self-replicating vector pEff based on potato virus X genome. The recombinant protein Flg-RBD was expressed at the level of about 110–140 μg per gram of fresh leaf tissue and was found to be insoluble. The fusion protein was purified using metal affinity chromatography under denaturing conditions. To increase the yield of Flg-RBD, the flow-through fraction obtained after loading of the protein sample on the Ni-NTA resin was re-loaded on the sorbent. The yield of Flg-RBD after purification reached about 100 μg per gram of fresh leaf tissue and the purified protein remained soluble after dialysis. The control flagellin was expressed in a soluble form and its yield after purification was about 300 μg per gram of fresh leaf biomass. Plant-produced Flg-RBD protein could be further used for the development of intranasal recombinant mucosal vaccines against COVID-19.
An Improved Method for the Extraction of Nucleic Acids from Plant Tissue without Grinding to Detect Plant Viruses and Viroids
Authors: Hataya Tatsuji
Published: December 2021

Gene amplification techniques such as polymerase chain reaction (PCR) are widely used for the diagnosis of plant diseases caused by viruses and viroids. It is preferable that sample preparation methods for PCR or reverse transcription (RT) PCR are rapid, straightforward, and inexpensive. We previously reported a method for the extraction of nucleic acids without mechanical tissue grinding using a buffer containing potassium ethyl xanthogenate (PEX) to detect viroid RNAs. In the present report, the previous PEX method was improved and simplified. In the simplified PEX (SPEX) method, the process of PEX buffer treatment for plant cell wall disruption is improved to one step of incubation at 80 °C for 10 min, instead of three steps that took more than 26 min at 65 °C in the previous method. Total nucleic acids could be extracted from fresh, frozen, or dried leaves of a cultivar or wild species of tobacco, tomato, citron, hop plants, and pericarps of persimmon fruits by the SPEX method. Several RNA viruses and viroids were successfully detected from the extracted nucleic acids together with an internal mRNA by RT-PCR. The SPEX method may be useful for detecting not only viruses and viroids, but also other plant pathogens.
High Antioxidant Ability Confer Resistance to Atrazine in Commelina communis L.
Authors: Yang Juan , Yu Haiyan , Cui Hailan , Chen Jingchao , Li Xiangju
Published: December 2021

Asiatic dayflower (Commelina communis L.) is a detrimental weed that mainly infests corn and soybean fields in China. Recently, some C. communis populations have exhibited resistance to atrazine, intensifying the difficulties in controlling the weed. However, little is known on the mechanism underlying C. communis resistance to atrazine. Therefore, two populations collected from Jilin (JL-1) and Jiangsu (JS-10) provinces of China were used to evaluate their growth responses to atrazine. The results showed that the JL-1 population displayed a low level of resistance to atrazine compared with JS-10 population, with the resistant index (RI) value of 2.9. To determine if a mutation in the psbA gene was the basis for varied resistance to this herbicide, the full-length gene encoding 353 amino acids with no intron was sequenced by using genome-walking techniques. No mutation known to confer resistance to atrazine was observed in either JL-1 or JS-10 populations. The malondialdehyde (MDA) contents relative to the control group were significantly higher in JS-10 population than in JL-1 population at 7 days after treatment with atrazine, suggesting that atrazine induced severer oxidant damage on JS-10 population. Additionally, significantly enhanced activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX), were detected in the JL-1 population, which was most likely to confer resistance to atrazine. To the best of our knowledge, this is the first investigation into the potential genetic and enzymatic differences contributing to atrazine resistance in this population.
Preliminary Phytochemical Screening, In Vitro Antidiabetic, Antioxidant Activities, and Toxicity of Leaf Extracts of Psychotria malayana Jack
Authors: Nipun Tanzina Sharmin , Khatib Alfi , Ahmed Qamar Uddin , Nasir Mohd Hamzah Mohd , Supandi Farahaniza , Taher Muhammad , Saiman Mohd Zuwairi
Published: December 2021

Psychotria malayana Jack belongs to the Rubiacea and is widespread in Southeast Asian countries. It is traditionally used to treat diabetes. Despite its potential medicinal use, scientific proof of this pharmacological action and the toxic effect of this plant are still lacking. Hence, this study aimed to investigate the in vitro antidiabetic and antioxidant activities, toxicity, and preliminary phytochemical screening of P. malayana leaf extracts by gas chromatography-mass spectrometry (GC-MS) after derivatization. The antidiabetic activities of different extracts of this plant were investigated through alpha-glucosidase inhibitory (AGI) and 2-NBDG glucose uptake using 3T3-L1 cell line assays, while the antioxidant activity was evaluated using DPPH and FRAP assays. Its toxicological effect was investigated using the zebrafish embryo/larvae (Danio rerio) model. The mortality, hatchability, tail-detachment, yolk size, eye size, beat per minute (BPM), and body length were taken into account to observe the teratogenicity in all zebrafish embryos exposed to methanol extract. The LC50 was determined using probit analysis. The methanol extract showed the AGI activity (IC50 = 2.71 ± 0.11 μg/mL), insulin-sensitizing activity (at a concentration of 5 µg/mL), and potent antioxidant activities (IC50 = 10.85 μg/mL and 72.53 mg AAE/g for DPPH and FRAP activity, respectively). Similarly, the water extract exhibited AGI activity (IC50 = 6.75 μg/mL), insulin-sensitizing activity at the concentration of 10 μg/mL, and antioxidant activities (IC50 = 27.12 and 33.71 μg/mL for DPPH and FRAP activity, respectively). The methanol and water extracts exhibited the LC50 value higher than their therapeutic concentration, i.e., 37.50 and 252.45 µg/mL, respectively. These results indicate that both water and methanol extracts are safe and potentially an antidiabetic agent, but the former is preferable since its therapeutic index (LC50/therapeutic concentration) is much higher than for methanol extracts. Analysis using GC-MS on derivatized methanol and water extracts of P. malayana leaves detected partial information on some constituents including palmitic acid, 1,3,5-benzenetriol, 1-monopalmitin, beta-tocopherol, 24-epicampesterol, alpha-tocopherol, and stigmast-5-ene, that could be a potential target to further investigate the antidiabetic properties of the plant. Nevertheless, isolation and identification of the bioactive compounds are required to confirm their antidiabetic activity and toxicity.
Impacts of Carbon Dioxide Enrichment on Landrace and Released Ethiopian Barley (Hordeum vulgare L.) Cultivars
Authors: Gardi Mekides Woldegiorgis , Malik Waqas Ahmed , Haussmann Bettina I. G.
Published: December 2021

Barley (Hordeum vulgare L.) is an important food security crop due to its high-stress tolerance. This study explored the effects of CO2 enrichment (eCO2) on the growth, yield, and water-use efficiency of Ethiopian barley cultivars (15 landraces, 15 released). Cultivars were grown under two levels of CO2 concentration (400 and 550 ppm) in climate chambers, and each level was replicated three times. A significant positive effect of eCO2 enrichment was observed on plant height by 9.5 and 6.7%, vegetative biomass by 7.6 and 9.4%, and grain yield by 34.1 and 40.6% in landraces and released cultivars, respectively. The observed increment of grain yield mainly resulted from the significant positive effect of eCO2 on grain number per plant. The water-use efficiency of vegetative biomass and grain yield significantly increased by 7.9 and 33.3% in landraces, with 9.5 and 42.9% improvement in released cultivars, respectively. Pearson’s correlation analysis revealed positive relationships between grain yield and grain number (r = 0.95), harvest index (r = 0.86), and ear biomass (r = 0.85). The response of barley to eCO2 was cultivar dependent, i.e., the highest grain yield response to eCO2 was observed for Lan_15 (122.3%) and Rel_10 (140.2%). However, Lan_13, Land_14, and Rel_3 showed reduced grain yield by 16, 25, and 42%, respectively, in response to eCO2 enrichment. While the released cultivars benefited more from higher levels of CO2 in relative terms, some landraces displayed better actual values. Under future climate conditions, i.e., future CO2 concentrations, grain yield production could benefit from the promotion of landrace and released cultivars with higher grain numbers and higher levels of water-use efficiency of the grain. The superior cultivars that were identified in the present study represent valuable genetic resources for future barley breeding.
Wrinkling on Stimuli-Responsive Functional Polymer Surfaces as a Promising Strategy for the Preparation of Effective Antibacterial/Antibiofouling Surfaces
Authors: González-Henríquez Carmen M. , Rodríguez-Umanzor Fernando E. , Alegría-Gómez Matías N. , Terraza-Inostroza Claudio A. , Martínez-Campos Enrique , Cue-López Raquel , Sarabia-Vallejos Mauricio A. , García-Herrera Claudio , Rodríguez-Hernández Juan
Published: December 2021

Biocompatible smart interfaces play a crucial role in biomedical or tissue engineering applications, where their ability to actively change their conformation or physico-chemical properties permits finely tuning their surface attributes. Polyelectrolytes, such as acrylic acid, are a particular type of smart polymers that present pH responsiveness. This work aims to fabricate stable hydrogel films with reversible pH responsiveness that could spontaneously form wrinkled surface patterns. For this purpose, the photosensitive reaction mixtures were deposited via spin-coating over functionalized glasses. Following vacuum, UV, or either plasma treatments, it is possible to spontaneously form wrinkles, which could increase cell adherence. The pH responsiveness of the material was evaluated, observing an abrupt variation in the film thickness as a function of the environmental pH. Moreover, the presence of the carboxylic acid functional groups at the interface was evidenced by analyzing the adsorption/desorption capacity using methylene blue as a cationic dye model. The results demonstrated that increasing the acrylic acid in the microwrinkled hydrogel effectively improved the adsorption and release capacity and the ability of the carboxylic groups to establish ionic interactions with methylene blue. Finally, the role of the acrylic acid groups and the surface topography (smooth or wrinkled) on the final antibacterial properties were investigated, demonstrating their efficacy against both gram-positive and gram-negative bacteria model strains (E. coli and S. Aureus). According to our findings, microwrinkled hydrogels presented excellent antibacterial properties improving the results obtained for planar (smooth) hydrogels.
Thermoplastic Starch-Based Blends with Improved Thermal and Thermomechanical Properties
Authors: Estrada-Monje Anayansi , Alonso-Romero Sergio , Zitzumbo-Guzmán Roberto , Estrada-Moreno Iván Alziri , Zaragoza-Contreras Erasto Armando
Published: December 2021

This research focused on the development of biomaterials based on cassava starch and corn starch and on the effect of the incorporation of polycaprolactone (PCL) on the thermal and thermomechanical properties of the blends. The results indicated partial compatibility in the blends, especially with cassava starch at a content of 20 wt% as reflected by the maintenance of tensile strength and elongation. In addition, the changes in the crystal quality of PCL and the displacement of the absorption bands of the carbonyl groups of PCL in the infrared (989–1000 cm−1), attributed to the formation of hydrogen bonds between these groups and the hydroxyl groups of starches, were also associated with compatibility. It was observed that the crystallinity of PLC in the presence of cassava and corn starch was 38% and 62%, respectively; a crystallinity greater than that of PCL was related to an improved nucleation at the interface. Based on these properties, the blends are expected to be functional for the manufacture of short-term use products by conventional thermoplastic processing methods.
Analysis and Calculation of Stability Coefficients of Cross-Laminated Timber Axial Compression Member
Authors: Ye Qi , Gong Yingchun , Ren Haiqing , Guan Cheng , Wu Guofang , Chen Xu
Published: December 2021

Cross-laminated timber (CLT) elements are becoming increasingly popular in multi-storey timber-based structures, which have long been built in many different countries. Various challenges are connected with constructions of this type. One such challenge is that of stabilizing the structure against vertical loads. However, the calculations of the stability bearing capacity of the CLT members in axial compression in the structural design remains unsolved in China. This study aims to determine the stability bearing capacity of the CLT members in axial compression and to propose the calculation method of the stability coefficient. First, the stability coefficient calculation theories in different national standards were analyzed, and then the stability bearing capacity of CLT elements with four slenderness ratios was investigated. Finally, based on the stability coefficient calculation formulae in the GB 50005-2017 standard and the regression method, the calculation method of the stability coefficient for CLT elements was proposed, and the values of the material parameters were determined. The result shows that the average deviation between fitting curve and calculated results of European and American standard is 5.43% and 3.73%, respectively, and the average deviation between the fitting curve and the actual test results was 8.15%. The stability coefficients calculation formulae could be used to predict the stability coefficients of CLT specimens with different slenderness ratios well.
Facile Molecular Weight Determination of Polymer Brushes Grafted from One-Dimensional Diffraction Grating by SI-ATRP Using Reflective Laser System
Authors: Chen Jem-Kun , Lin Feng-Ping , Chang Chi-Jung , Lu Chien-Hsing , Huang Chih-Feng
Published: December 2021

Gelatin was immobilized selectively on the amide groups-modified bottom of a trench array of a photoresist template with 2 μm resolution by the ethyl(dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide reaction. The gelatin-immobilized line array was brominated to generate a macroinitiator for atom transfer radical polymerization. Poly(methacrylic acid) (PMAA) brushes were grafted from the macroinitiator layer as line arrays of one-dimensional diffraction gratings (DGs) for various grafting polymerization times. A laser beam system was employed to analyze the optical feature with a characteristic diffraction effect of the PMAA DGs at a 45° incident angle along the transverse magnetic and transverse electric polarization. The growth of the PMAA brush lines increased both their heights and widths, leading to a change in the reflective diffraction intensity. The PMAA brushes under various grafting polymerization times were cleaved from the substrate by digestion of gelatin with trypsin, and their molecular weights were obtained by gel permeation chromatography. The change degree of the diffraction intensity varied linearly with the molecular weight of the PMAA brushes over a wide range, from 135 to 1475 kDa, with high correlation coefficients. Molecular weight determination of polymer brushes using the reflective diffraction intensity provides a simple method to monitor their growth in real time without polymer brush cleavage.
Expanding Poly(lactic acid) (PLA) and Polyhydroxyalkanoates (PHAs) Applications: A Review on Modifications and Effects
Authors: Naser Ahmed Z. , Deiab Ibrahim , Defersha Fantahun , Yang Sheng
Published: December 2021

The high price of petroleum, overconsumption of plastic products, recent climate change regulations, the lack of landfill spaces in addition to the ever-growing population are considered the driving forces for introducing sustainable biodegradable solutions for greener environment. Due to the harmful impact of petroleum waste plastics on human health, environment and ecosystems, societies have been moving towards the adoption of biodegradable natural based polymers whose conversion and consumption are environmentally friendly. Therefore, biodegradable biobased polymers such as poly(lactic acid) (PLA) and polyhydroxyalkanoates (PHAs) have gained a significant amount of attention in recent years. Nonetheless, some of the vital limitations to the broader use of these biopolymers are that they are less flexible and have less impact resistance when compared to petroleum-based plastics (e.g., polypropylene (PP), high-density polyethylene (HDPE) and polystyrene (PS)). Recent advances have shown that with appropriate modification methods—plasticizers and fillers, polymer blends and nanocomposites, such limitations of both polymers can be overcome. This work is meant to widen the applicability of both polymers by reviewing the available materials on these methods and their impacts with a focus on the mechanical properties. This literature investigation leads to the conclusion that both PLA and PHAs show strong candidacy in expanding their utilizations to potentially substitute petroleum-based plastics in various applications, including but not limited to, food, active packaging, surgical implants, dental, drug delivery, biomedical as well as antistatic and flame retardants applications.
Low-Temperature Mechano-Chemical Rubber Reclamation Using Terpinene as a Swelling Agent to Enhance Bond-Breaking Selectivity
Authors: Guo Lei , Ren Donghui , Wang Wenchao , Hao Kuanfa , Guo Xiurui , Liu Fumin , Xu Yuan , Liu Miaomiao , Liu Haichao
Published: December 2021

Common swelling agents used in the mechano-chemical rubber devulcanization process usually require high temperatures to achieve satisfactory swelling effects, which results in severe production of pollutants and reduces the selectivity of bond scissions. This work presents an environmentally friendly swelling agent, terpinene, which can swell the rubber crosslink structures at low temperatures. Both a rubber swelling experiment and a rubber reclaiming experiment with a mechano-chemical devulcanization method are conducted to explore the swelling effects of terpinene. After soaking in terpinene at 60 °C for 90 min, the length elongation of the rubber sample reaches 1.55, which is much higher than that in naphthenic oil and is comparable to that in toluene. When adding 3 phr of terpinene for every 100 phr of waste rubber during the reclaiming process, the bond scissions exhibit high selectivity. After revulcanization, the reclaimed rubbers have a tensile strength of 17 MPa and a breaking elongation of 400%. Consequently, the application of terpinene as the swelling agent in the LTMD method can greatly improve the properties of reclaimed rubbers, thereby enhancing the dual value for the economy and environment.
Development of a New Formulation Based on In Situ Photopolymerized Polymer for the Treatment of Spinal Cord Injury
Authors: Novais Gabrielle B. , dos Santos Stefane , Santana Robertta J. R. , Filho Rose N. P. , Cunha John L. S. , Lima Bruno S. , Araújo Adriano A. S. , Severino Patricia , Júnior Ricardo L. C. Albuquerque , Cardoso Juliana C. , Souto Eliana B. , Gomes Margarete Z.
Published: December 2021

Spinal Cord Injury (SCI) promotes a cascade of inflammatory events that are responsible for neuronal death and glial scar formation at the site of the injury, hindering tissue neuroregeneration. Among the main approaches for the treatment of SCI, the use of biomaterials, especially gelatin methacryloyl (GelMA), has been proposed because it is biocompatible, has excellent mechanical properties, favoring cell adhesion and proliferation. In addition, it can act as a carrier of anti-inflammatory drugs, preventing the formation of glial scars. The present work presents the development and in situ application of a light-curing formulation based on GelMA containing a natural extract rich in anti-inflammatory, antioxidant and neuroprotective substances (hydroalcoholic extract of red propolis—HERP) in an experimental model of SCI in rats. The formulations were prepared and characterized by time of UV exposition, FTIR, swelling and degradation. The hydrogels containing 1 mg/mL of HERP were obtained by the exposure to UV radiation of 2 μL of the formulation for 60 s. The locomotor evaluation of the animals was performed by the scale (BBB) and demonstrated that after 3 and 7 days of the injury, the GelMA-HERP group (BBB = 5 and 7) presented greater recovery compared to the GelMA group (BBB = 4 and 5). Regarding the inflammatory process, using histomorphological techniques, there was an inflammation reduction in the groups treated with GelMA and GelMA-HERP, with decreases of cavitation in the injury site. Therefore, it is possible to conclude that the use of GelMA and GelMA-HERP hydrogel formulations is a promising strategy for the treatment of SCI when applied in situ, as soon as possible after the injury, improving the clinical and inflammatory conditions of the treated animals.
Properties of Biocomposite Film Based on Whey Protein Isolate Filled with Nanocrystalline Cellulose from Pineapple Crown Leaf
Authors: Fitriani Fitriani , Aprilia Sri , Arahman Nasrul , Bilad Muhammad Roil , Suhaimi Hazwani , Huda Nurul
Published: December 2021

Among the main bio-based polymer for food packaging materials, whey protein isolate (WPI) is one of the biopolymers that have excellent film-forming properties and are environmentally friendly. This study was performed to analyse the effect of various concentrations of bio-based nanocrystalline cellulose (NCC) extracted from pineapple crown leaf (PCL) on the properties of whey protein isolate (WPI) films using the solution casting technique. Six WPI films were fabricated with different loadings of NCC from 0 to 10 % w/v. The resulting films were characterised based on their mechanical, physical, chemical, and thermal properties. The results show that NCC loadings increased the thickness of the resulting films. The transparency of the films decreased at higher NCC loadings. The moisture content and moisture absorption of the films decreased with the presence of the NCC, being lower at higher NCC loadings. The water solubility of the films decreased from 92.2% for the pure WPI to 65.5% for the one containing 10 % w/v of NCC. The tensile strength of the films peaked at 7% NCC loading with the value of 5.1 MPa. Conversely, the trend of the elongation at break data was the opposite of the tensile strength. Moreover, the addition of NCC produced a slight effect of NCC in FTIR spectra of the WPI films using principal component analysis. NCC loading enhanced the thermal stability of the WPI films, as shown by an increase in the glass transition temperature at higher NCC loadings. Moreover, the morphology of the films turned rougher and more heterogeneous with small particle aggregates in the presence of the NCC. Overall, the addition of NCC enhanced the water barrier and mechanical properties of the WPI films by incorporating the PCL-based NCC as the filler.
Impact of Vapor Barrier on Moisture Content of Fiberboard Insulation in Log Structure
Authors: Jochim Stanislav , Uhrín Róbert , Schmidtová Jarmila , Sedlák Pavol , Búryová Dominika , Střelcová Katarína
Published: December 2021

The paper is focused on a verification of the moisture content of fiberboard insulations in the multilayer loadbearing log wall designed with and without the vapor barrier. Experimental verification was done using a sample of the multilayer loadbearing log wall built in a research timber structure building under in-situ conditions. Indoor properties of the building met conditions for human occupancy. The experiment was performed for 2 years and 3 months. Aims of the fiberboard insulations moisture content verification in the walls were to verify the effect of vapor barrier in various periods of the year and verify excessive moisture in the fiberboard insulations, which is undesirable in terms of biodegradation. The results of measuring the moisture content showed that after a certain period, the difference of insulation moisture content in the wall including and excluding vapor barrier is negligible, as well as other results and conclusions for designing the composition of multilayer loadbearing log walls.
Electrospun Structural Hybrids of Acyclovir-Polyacrylonitrile at Acyclovir for Modifying Drug Release
Authors: Lv He , Guo Shiri , Zhang Gaoyi , He Wanli , Wu Yonghui , Yu Deng-Guang
Published: December 2021

In traditional pharmaceutics, drug–crystalline nanoparticles and drug–polymer composites are frequently explored for their ability to modify drug release profiles. In this study, a novel sort of hybrid with a coating of acyclovir crystalline nanoparticles on acyclovir-polyacrylonitrile composites was fabricated using modified, coaxial electrospinning processes. The developed acyclovir-polyacrylonitrile at the acyclovir nanohybrids was loaded with various amounts of acyclovir, which could be realized simply by adjusting the sheath fluid flow rates. Compared with the electrospun composite nanofibers from a single-fluid blending process, the nanohybrids showed advantages of modifying the acyclovir release profiles in the following aspects: (1) the initial release amount was more accurately and intentionally controlled; (2) the later sustained release was nearer to a zero-order kinetic process; and (3) the release amounts at different stages could be easily allocated by the sheath fluid flow rate. X-ray diffraction results verified that the acyclovir nanoparticles were in a crystalline state, and Fourier-transform infrared spectra verified that the drug acyclovir and the polymer polyacrylonitrile had a good compatibility. The protocols reported here could pave the way for developing new types of functional nanostructures.
Evaluation of the Sensitivity of Various Reinforcement Patterns for Structural Carbon Fibers to Open Holes during Tensile Tests
Authors: Strungar Elena , Lobanov Dmitrii , Wildemann Valery
Published: December 2021

This paper is devoted to the experimental study of polymeric composite specimens, with various types of reinforcement, in order to evaluate the breaking strength of specimens with open holes when undergoing uniaxial compression and tensile tests. Four types of interlaced 3D woven preforms were considered (orthogonal, orthogonal combined, with pairwise inter-layer reinforcement, and with pairwise inter-layer reinforcement and a longitudinal layer), with a layered preform used for comparison. Tensile tests of solid specimens without a hole, under ASTM D 3039, and of specimens with an open hole, under ASTM D 5766, were carried out using the Instron 5989 universal electromechanical testing system. Movements and strains on the specimen surface were recorded using a Vic-3D contactless optical video system and the digital images correlation method (DIC). For all the series of carbon fiber tension specimens, strain and stress diagrams, mechanical characteristics, and statistical processing for 10 specimens were obtained. The paper evaluated deformation fields for certain points in time; the obtained fields showed an irregular distribution of deformation and dependency on types of reinforcing fibers. A coefficient of strength variation is introduced, which is defined as a ratio of the ultimate stress limits obtained on solid samples with and without open holes. Within the framework of ASTM D 5766, when calculating the ultimate stress, the hole is not taken into account, and the paper shows that for certain structures a hole cannot be excluded. The hole size must not be neglected when calculating the ultimate stress.
Oxidative Coupling of Methane for Ethylene Production: Reviewing Kinetic Modelling Approaches, Thermodynamics and Catalysts
Authors: Da Ros Simoní , Barbalho Fontoura Tahyná , Schwaab Marcio , Castro de Jesus Normando , Pinto José
Published: December 2021

Ethylene production via oxidative coupling of methane (OCM) represents an interesting route for natural gas upscaling, being the focus of intensive research worldwide. Here, OCM developments are analysed in terms of kinetic mechanisms and respective applications in chemical reactor models, discussing current challenges and directions for further developments. Furthermore, some thermodynamic aspects of the OCM reactions are also revised, providing achievable olefins yields in a wide range of operational reaction conditions. Finally, OCM catalysts are reviewed in terms of respective catalytic performances and thermal stability, providing an executive summary for future studies on OCM economic feasibility.
Research and Application of Double-Reheat Boiler in China
Authors: Liu Hu , Yu Pengfei , Xue Jingwen , Deng Lei , Che Defu
Published: December 2021

The ultra-supercritical (USC) double-reheat technology is an immediate area of research focus in China, since the thermal efficiency of USC double-reheat unit is higher than the USC single-reheat unit. The parameters and capacity of USC double-reheat unit in China have made major breakthroughs, and the thermal efficiency of the units are as high as 47–48%, which is the highest in the world. USC double-reheat boiler is one of the most important devices for USC double-reheat unit, and the design concept and precision have a vital effect on the operation of boiler and power station. The most difficult and important factors in the design of double-reheat boiler are the layout of heating surface and the steam temperature regulation method. Therefore, this work summarizes the arrangement of heating surface and temperature regulation method of existing double-reheat boiler in China. It is hoped that the work will set a benchmark for the development of double-reheat boiler and the future 700 °C power generation unit in the world.
Removal of Emerging Pollutants in Horizontal Subsurface Flow and Vertical Flow Pilot-Scale Constructed Wetlands
Authors: Gikas Georgios D. , Papaevangelou Vassiliki A. , Tsihrintzis Vassilios A. , Antonopoulou Maria , Konstantinou Ioannis K.
Published: December 2021

We assessed constructed wetland (CW) performance in the removal of six emerging pollutants (EPs) from university campus wastewater. The EPs considered were: diethyl phthalate (DEP), di-isobutyl phthalate (DIBP), di-n-octyl phthalate (DNOP), bis(2-ehtylxexyl) phthalate (DEHP), tris(1-chloro-2-propyl) phosphate (TCPP) and caffeine (CAF). Six pilot-scale CWs, i.e., three horizontal subsurface flow (HSF) and three vertical flow (VF), with different design configurations were used: two types of plants and one unplanted for both the HSF and the VF, two hydraulic retention times (HRT) for the HSF, and two wastewater feeding strategies for the VF units. The results showed that the median removals in the three HSF-CWs ranged between 84.3 and 99.9%, 79.0 and 95.7%, 91.4 and 99.7%, 72.2 and 81.0%, 99.1 and 99.6%, and 99.3 and 99.6% for DEP, DIBP, DNOP, DEHP, TCPP, and CAF, respectively. In the three VF-CWs, the median removal efficiencies range was 98.6–99.4%, 63.6–98.0%, 96.6–97.8%, 73.6–94.5%, 99.3–99.5% and 94.4–96.3% for DEP, DIBP, DNOP, DEHP, TCPP and CAF, respectively. The study indicates that biodegradation and adsorption onto substrate were the most prevalent removal routes of the target EPs in CWs.
Biocompatible Osmium Telluride-Polypyrrole Nanocomposite Material: Application in Prostate Specific Antigen Immunosensing
Authors: Gupta Riya , Feleni Usisipho , Iwuoha Emmanuel
Published: December 2021

Prostate cancer is a dominant global threat to society. It affects nearly 4000 men in South Africa annually, making it the second most threatening cancerous disease after lung cancer. A potential serological biomarker to monitor early diagnosis of prostate cancer is prostate specific antigen (PSA). We used the PSA biomarker in our work to develop an extremely sensitive electrochemical immunosensor to achieve low detection limits. The fabrication steps followed with the combination of thioglycolic acid capped osmium telluride quantum dots (TGA-OsTe2QD)-polypyrrole (PPy) nanocomposite and prostate specific antigen modified on a glassy carbon electrode. The UV-Vis signatures of TGA-OsTe2QD-PPy showed an absorption band at 262 nm which is attributed to the PPy and TGA-OsTe2QD composite. This band corresponds to the energy band gap of 4.4 and 5.4 eV. The CV responses of BSA|Ab|TGA-OsTe2QD|PPy|GCE modified electrode to prostate specific antigen (PSA) was studied within a range of 0–16 ng/mL PSA that was linear, herein referred to as liner range (LR), which produced a limit of detection (LOD) value of 0.36 ng/mL PSA. The values of the immunosensor’s calibration parameters (LR and LOD) make them suitable for real sample application, due to their coverage of the PSA concentration range (0–14 ng/mL) that is of clinical importance.
Early–Middle Pleistocene Magnetostratigraphic and Rock Magnetic Records of the Dolynske Section (Lower Danube, Ukraine) and Their Application to the Correlation of Loess–Palaeosol Sequences in Eastern and South-Eastern Europe
Authors: Hlavatskyi Dmytro , Bakhmutov Vladimir
Published: December 2021

We present new palaeomagnetic and rock magnetic results with a stratigraphic interpretation of the late Early–Middle Pleistocene deposits exposed on the left bank of the River Danube at Dolynske, southern Ukraine. A thick succession of water-lain facies is succeeded by reddish-brown clayey soils, topped by a high-resolution loess–palaeosol sequence. These constitute one of the most complete recently discovered palaeoclimate archives in the Lower Danube Basin. The suggested stratigraphy is based on the position of the Matuyama–Brunhes boundary, rock magnetic, palaeopedological and sedimentological proxies, and it is confidently correlated with other loess records in the region (Roksolany and Kurortne), as well as with the marine isotope stratigraphy. The magnetic susceptibility records and palaeosol characteristics at Dolynske show an outstanding pattern that is transitional between eastern and south-eastern European loess records. Our data confirm that the well-developed S4 soil unit in Ukraine, and S5 units in Romania, Bulgaria and Serbia, correlate with the warm MIS 11. Furthermore, we suggest the correlation of rubified S6 palaeosols in Romania and Bulgaria and the V-S7–V-S8 double palaeosol in Serbia with S6 in Ukraine, a strong Mediterranean-type palaeosol which corresponds to MIS 15. Our new results do not support the hypothesis of a large magnetic lock-in depth like that previously interpreted for the Danube loess, and they prove that the Matuyama–Brunhes boundary is located within the palaeosol unit corresponding to MIS 19. The proposed stratigraphic correlation scheme may serve as a potential basis for further regional and global Pleistocene climatic reconstructions.
Introduction to the Special Issue: Theodicy and Challenges of Science: Understanding God, Evil and Evolution
Authors: Roszak Piotr , Horvat Sasa
Published: December 2021

In these “pandemic years” a number of scientific and humanistic questions arise [...]
An Empirical Study on the Nature of the Verbal Responses of Humanist Chaplains
Authors: Vos Jeroen de , Braam Arjan W.
Published: December 2021

There has been a limited amount of empirical research conducted in the past on how chaplains, and humanist chaplains in particular, actually interact with their clients during conversations as a part of spiritual care and counselling. The aim of the current study was to gain insight into the extent to which the verbal responses of humanist chaplains corresponded to Rogers’ nondirective approach during conversations with clients. Rogers’ approach has been commonly embraced since the beginning of the professionalization of humanist chaplains in the Netherlands. The study focused on humanist chaplains working at a general hospital in the Netherlands. Ten humanist chaplains took part in the study by audio recording their conversations with clients. The audio recordings were transcribed and analysed, and the verbal responses of humanist chaplains were compared to Rogers’ approach. Subsequently, the verbal responses were analysed via conversation analysis, which also provided insight into how the humanist chaplains actually conversed with clients. Most of the verbal responses (73%) were consistent with Rogers’ nondirective approach, though the ways in which some of the verbal responses were expressed were different; they were more compassionate and comforting. The remaining 27% of the verbal responses were directive and did not correspond to Rogers’ approach. The study shows that, compared to Rogers’ nondirective approach, the approach of the humanist chaplains was more direct and comforting.
Downside Beta and Downside Gamma: In Search for a Better Capital Asset Pricing Model
Authors: Kazmi Madiha , Noreen Umara , Jadoon Imran Abbas , Shafique Attayah
Published: December 2021

In the financial world, the importance of “downside risk” and “higher moments” has been emphasized, predominantly in developing countries such as Pakistan, for a substantial period. Consequently, this study tests four models for a suitable capital asset pricing model. These models are CAPM’s beta, beta replaced by skewness (gamma), CAPM’s beta with gamma, downside beta CAPM (DCAPM), downside beta replaced by downside gamma, and CAPM with downside gamma. The problems of the high correlation between the beta and downside beta models from a regressand point of view is resolved by constructing a double-sorted portfolio of each factor loading. The problem of the high correlation between the beta and gamma, and, similarly, between the downside beta and downside gamma, is resolved by orthogonalizing each risk measure in a two-factor setting. Standard two-pass regression is applied, and the results are reported and analyzed in terms of R2, the significance of the factor loadings, and the risk–return relationship in each model. The risk proxies of the downside beta/gamma are based on Hogan and Warren, Harlow and Rao, and Estrada. The results indicate that the single factor models based on the beta/downside beta or even gamma/downside gamma are not a better choice among all the risk proxies. However, the beta and gamma factors are rejected at a 5% and 1% significance level for different risk proxies. The obvious choice based on the results is an asset pricing model with two risk measures.