bluuebunny/crossref_metadata_2025 huggingface dataset:
One Step Closer to Enigmatic USCα Methanotrophs: Isolation of a Methylocapsa-like Bacterium from a Subarctic Soil
Authors: Danilova Olga V. , Oshkin Igor Y. , Belova Svetlana E. , Miroshnikov Kirill K. , Ivanova Anastasia A. , Dedysh Svetlana N.
Published: November 2023

The scavenging of atmospheric trace gases has been recognized as one of the lifestyle-defining capabilities of microorganisms in terrestrial polar ecosystems. Several metagenome-assembled genomes of as-yet-uncultivated methanotrophic bacteria, which consume atmospheric CH4 in these ecosystems, have been retrieved in cultivation-independent studies. In this study, we isolated and characterized a representative of these methanotrophs, strain D3K7, from a subarctic soil of northern Russia. Strain D3K7 grows on methane and methanol in a wide range of temperatures, between 5 and 30 °C. Weak growth was also observed on acetate. The presence of acetate in the culture medium stimulated growth at low CH4 concentrations (~100 p.p.m.v.). The finished genome sequence of strain D3K7 is 4.15 Mb in size and contains about 3700 protein-encoding genes. According to the result of phylogenomic analysis, this bacterium forms a common clade with metagenome-assembled genomes obtained from the active layer of a permafrost thaw gradient in Stordalen Mire, Abisco, Sweden, and the mineral cryosol at Axel Heiberg Island in the Canadian High Arctic. This clade occupies a phylogenetic position in between characterized Methylocapsa methanotrophs and representatives of the as-yet-uncultivated upland soil cluster alpha (USCα). As shown by the global distribution analysis, D3K7-like methanotrophs are not restricted to polar habitats but inhabit peatlands and soils of various climatic zones.
Effects of Short-Term Acidification on the Adsorption of Dissolved Organic Matter by Soil Minerals and Its Mechanism of Action
Authors: Chen Yueting , Wang Yue , Wang Xuqin , Luan Yaning , Dai Wei
Published: November 2023

In order to investigate the impact of soil acidification on the adsorption of dissolved organic matter by soil minerals and understand its mechanism, this study selected commonly found minerals in soils, namely illite, kaolin, and hematite, as the research objects. Glucose and tannic acid were considered as the representative compounds for studying the adsorption of dissolved organic matter in soils. By analyzing the effects of the three minerals on the adsorption characteristics of glucose and tannic acid after a short-term acidification treatment, this study aimed to explore the underlying mechanism. To achieve this, scanning electron microscopy and a specific surface area analyzer were utilized. The results of this study indicate that the adsorption modes of the minerals studied were unaffected by short-term acidification. Chemisorption, as well as surface and mesopore diffusion, were found to dominate the adsorption process. In terms of adsorption behavior, the minerals exhibited multilayer inhomogeneous adsorption with glucose and kaolin, while tannic acid showed monolayer adsorption with illite and hematite. When exposed to the same acidification conditions, the saturated adsorption of glucose and tannic acid was found to be illite ≥ hematite > kaolin. The kinetic adsorption processes exhibited three stages: fast adsorption, slow adsorption, and adsorption equilibrium. Interestingly, as the intensity of the acidification increased, the saturated adsorption capacity generally followed the trend of S3 (test minerals with pH adjusted to 3 value) > S5 (test minerals with pH adjusted to 5 value) > CK (the control group). The acidification-induced solvation led to an increase in the specific surface area and the number of active adsorption sites on the minerals. Additionally, the protonation reaction triggered a change in the surface charge, which in turn affected the hydrogen bonding, ligand exchange, and charge transfer between the minerals and glucose and tannic acids. These interactions ultimately enhanced the adsorption capacity.
Methods and Protocols—Aims and Scope Update
Authors: Albericio Fernando , Hublitz Philip
Published: November 2023

As our readers know, Methods and Protocols is a multidisciplinary peer-reviewed scientific journal that provides a forum to the publication of novel approaches in the fields of Life Sciences, Chemistry, and Biomedical Sciences and their intersection with other related scientific fields such as Physics, Earth Sciences, and Environmental Research [...]
A Commercial Clay-Based Material as a Carrier for Targeted Lysozyme Delivery in Animal Feed
Authors: Guagliano Marianna , Cristiani Cinzia , Dell’Anno Matteo , Dotelli Giovanni , Finocchio Elisabetta , Lacalamita Maria , Mesto Ernesto , Reggi Serena , Rossi Luciana , Schingaro Emanuela
Published: November 2023

The controlled supply of bioactive molecules is a subject of debate in animal nutrition. The release of bioactive molecules in the target organ, in this case the intestine, results in improved feed, as well as having a lower environmental impact. However, the degradation of bioactive molecules’ in transit in the gastrointestinal passage is still an unresolved issue. This paper discusses the feasibility of a simple and cost-effective procedure to bypass the degradation problem. A solid/liquid adsorption procedure was applied, and the operating parameters (pH, reaction time, and LY initial concentration) were studied. Lysozyme is used in this work as a representative bioactive molecule, while Adsorbo®, a commercial mixture of clay minerals and zeolites which meets current feed regulations, is used as the carrier. A maximum LY loading of 32 mgLY/gAD (LY(32)-AD) was obtained, with fixing pH in the range 7.5–8, initial LY content at 37.5 mgLY/gAD, and reaction time at 30 min. A full characterisation of the hybrid organoclay highlighted that LY molecules were homogeneously spread on the carrier’s surface, where the LY–carrier interaction was mainly due to charge interaction. Preliminary release tests performed on the LY(32)-AD synthesised sample showed a higher releasing capacity, raising the pH from 3 to 7. In addition, a preliminary Trolox equivalent antioxidant capacity (TEAC) assay showed an antioxidant capacity for the LY of 1.47 ± 0.18 µmol TroloxEq/g with an inhibition percentage of 33.20 ± 3.94%.
Recent Development and Applications of Stretchable SERS Substrates
Authors: Peng Ran , Zhang Tingting , Yan Sheng , Song Yongxin , Liu Xinyu , Wang Junsheng
Published: November 2023

Surface-enhanced Raman scattering (SERS) is a cutting-edge technique for highly sensitive analysis of chemicals and molecules. Traditional SERS-active nanostructures are constructed on rigid substrates where the nanogaps providing hot-spots of Raman signals are fixed, and sample loading is unsatisfactory due to the unconformable attachment of substrates on irregular sample surfaces. A flexible SERS substrate enables conformable sample loading and, thus, highly sensitive Raman detection but still with limited detection capabilities. Stretchable SERS substrates with flexible sample loading structures and controllable hot-spot size provide a new strategy for improving the sample loading efficiency and SERS detection sensitivity. This review summarizes and discusses recent development and applications of the newly conceptual stretchable SERS substrates. A roadmap of the development of SERS substrates is reviewed, and fabrication techniques of stretchable SERS substrates are summarized, followed by an exhibition of the applications of these stretchable SERS substrates. Finally, challenges and perspectives of the stretchable SERS substrates are presented. This review provides an overview of the development of SERS substrates and sheds light on the design, fabrication, and application of stretchable SERS systems.
Sea Cucumber Peptides Ameliorate DSS-Induced Ulcerative Colitis: The Role of the Gut Microbiota, the Intestinal Barrier, and Macrophage Polarization
Authors: Yu Song , Guo Haixiang , Ji Zhonghao , Zheng Yi , Wang Bingbing , Chen Qingqing , Tang Hongyu , Yuan Bao
Published: November 2023

The incidence of ulcerative colitis (UC) is increasing annually. There are few treatments for UC patients, and some drugs have serious side effects. Sea cucumber peptide (SCP) has anti-inflammatory, antioxidant and other biological activities, and various sea cucumber species are in pharmaceutical development. However, relevant studies on the effects of SCP on UC progression are still lacking. In this study, a mouse model of acute colitis was induced by 3% dextran sulfate (DSS), and the effect of 500 mg/kg SCP on colitis was investigated. The results showed that SCP can alleviate DSS-induced colon damage and intestinal barrier damage. SCP significantly inhibited the expression of inflammatory factors and oxidative stress in UC mice. SCP reversed the intestinal microbiota dysregulation induced by DSS, inhibited the growth of Sutterella, Prevotella_9 and Escherichia-Shigella harmful bacteria, and increased the abundance of Lachnospiraceae_NK4A136_group. At the same time, SCP treatment significantly inhibited the LPS-induced polarization of M1 macrophages, which may be mediated by two monopeptides, IPGAPGVP and TGPIGPPGSP, via FPR2. In conclusion, SCP can protect against colitis by modulating the intestinal microbiota composition and the intestinal barrier and inhibiting the polarization of M1 macrophages.
Dietary Polyphenols—Natural Bioactive Compounds with Potential for Preventing and Treating Some Allergic Conditions
Authors: Dębińska Anna , Sozańska Barbara
Published: November 2023

In light of the constantly increasing prevalence of allergic diseases, changes in dietary patterns have been suggested as a plausible environmental explanation for the development and progression of these diseases. Nowadays, much attention has been paid to the development of dietary interventions using natural substances with anti-allergy activities. In this respect, dietary polyphenols have been studied extensively as one of the most prominent natural bioactive compounds with well-documented anti-inflammatory, antioxidant, and immunomodulatory properties. This review aims to discuss the mechanisms underlying the potential anti-allergic actions of polyphenols related to their ability to reduce protein allergenicity, regulate immune response, and gut microbiome modification; however, these issues need to be elucidated in detail. This paper reviews the current evidence from experimental and clinical studies confirming that various polyphenols such as quercetin, curcumin, resveratrol, catechins, and many others could attenuate allergic inflammation, alleviate the symptoms of food allergy, asthma, and allergic rhinitis, and prevent the development of allergic immune response. Conclusively, dietary polyphenols are endowed with great anti-allergic potential and therefore could be used either for preventive approaches or therapeutic interventions in relation to allergic diseases. Limitations in studying and widespread use of polyphenols as well as future research directions are also discussed.
Evaluation of Dietary and Alcohol Drinking Patterns in Patients with Excess Body Weight in a Spanish Cohort: Impact on Cardiometabolic Risk Factors
Authors: Aguas-Ayesa Maite , Yárnoz-Esquiroz Patricia , Olazarán Laura , Perdomo Carolina M. , García-Goñi Marta , Andrada Patricia , Escalada Javier , Silva Camilo , Marcos Ascensión , Frühbeck Gema
Published: November 2023

Unhealthy dietary habits and sedentarism coexist with a rising incidence of excess weight and associated comorbidities. We aimed to analyze the dietary and drinking patterns of patients with excess weight, their main characteristics, plausible gender differences and impact on cardiometabolic risk factors, with a particular focus on the potential contribution of beer consumption. Data from 200 consecutive volunteers (38 ± 12 years; 72% females) living with overweight or class I obesity attending the obesity unit to lose weight were studied. Food frequency questionnaires and 24 h recalls were used. Reduced-rank regression (RRR) analysis was applied to identify dietary patterns (DPs). Anthropometry, total and visceral fat, indirect calorimetry, physical activity level, comorbidities and circulating cardiometabolic risk factors were assessed. Study participants showed high waist circumference, adiposity, insulin resistance, dyslipidemia, pro-inflammatory adipokines and low anti-inflammatory factors like adiponectin and interleukin-4. A low-fiber, high-fat, energy-dense DP was observed. BMI showed a statistically significant (p < 0.05) correlation with energy density (r = 0.80) as well as percentage of energy derived from fat (r = 0.61). Excess weight was associated with a DP low in vegetables, legumes and whole grains at the same time as being high in sweets, sugar-sweetened beverages, fat spreads, and processed meats. RRR analysis identified a DP characterized by high energy density and saturated fat exhibiting negative loadings (>−0.30) for green leafy vegetables, legumes, and fruits at the same time as showing positive factor loadings (>0.30) for processed foods, fat spreads, sugar-sweetened beverages, and sweets. Interestingly, for both women and men, wine represented globally the main source of total alcohol intake (p < 0.05) as compared to beer and distillates. Beer consumption cannot be blamed as the main culprit of excess weight. Capturing the DP provides more clinically relevant and useful information. The focus on consumption of single nutrients does not resemble real-world intake behaviors.
Momordica balsamina L.: A Plant with Multiple Therapeutic and Nutritional Potential—A Review
Authors: Thiaw Marème , Samb Issa , Genva Manon , Gaye Mohamed Lamine , Fauconnier Marie-Laure
Published: November 2023

This review seeks to deepen our comprehension of the African plant Momordica balsamina L. by elucidating its therapeutically important molecules and nutrient composition. Commonly referred to as the balsam apple, this plant species is extensively harnessed for its diverse therapeutic potential across its various organs, including leaves, fruits, roots, and stems. Numerous bioactive molecules have been isolated or identified within this plant, notably encompassing polyphenols, flavonoids, terpenes, and carotenoids. These compounds exhibit a wide array of biological activities, ranging from antioxidative, anti-inflammatory, anti-diabetic and anti-carcinogenic to anti-malarial properties, among others. Furthermore, the leaves of Momordica balsamina L. stand out for their abundant micronutrients, proteins, and amino acids. This investigation aims to shed light not only on the botanical characteristics of the Momordica balsamina plant and its potential applications in traditional medicine but also on its chemical composition, biological functionalities, and physicochemical attributes, thus accentuating its nutritional advantages. Nonetheless, an intriguing avenue presents itself for the exploration of strategies to conserve this species, delve deeper into its potential within the cosmetics industry, and innovate methodologies for the synthesis or biosynthesis of these bioactive molecules.
In Vivo Biomechanical Response of the Human Cornea to Acoustic Waves
Authors: Ávila Francisco J. , Marcellán Maria Concepción , Remón Laura
Published: November 2023

The cornea is the optical window to the brain. Its optical and structural properties are responsible for optical transparency and vision. The shape, elasticity, rigidity, or stiffness are due to its biomechanical properties, whose stability results in ocular integrity and intraocular pressure dynamics. Here, we report in vivo observations of shape changes and biomechanical alterations in the human cornea induced by acoustic wave pressure within the frequency range of 50–350 Hz and the sound pressure level of 90 dB. The central corneal thickness (CCT) and eccentricity (e2) were measured using Scheimpflug imaging and biomechanical properties [corneal hysteresis (CH) and intraocular pressure (IOP)] were assessed with air-puff tonometry in six young, healthy volunteers. At the specific 150 Hz acoustic frequency, the variations in e2 and CCT were 0.058 and 7.33 µm, respectively. Biomechanical alterations were also observed in both the IOP (a decrease of 3.60 mmHg) and CH (an increase of 0.40 mmHg).
Cardiac Abnormalities in a Predictive Mouse Model of Chagas Disease
Authors: Francisco Amanda Fortes , Sousa Giovane R. , Vaughan Mhairi , Langston Harry , Khan Archie , Jayawardhana Shiromani , Taylor Martin C. , Lewis Michael D. , Kelly John M.
Published: November 2023

Chronic Chagas cardiomyopathy (CCC) results from infection with the protozoan parasite Trypanosoma cruzi and is a prevalent cause of heart disease in endemic countries. We previously found that cardiac fibrosis can vary widely in C3H/HeN mice chronically infected with T. cruzi JR strain, mirroring the spectrum of heart disease in humans. In this study, we examined functional cardiac abnormalities in this host:parasite combination to determine its potential as an experimental model for CCC. We utilised electrocardiography (ECG) to monitor T. cruzi-infected mice and determine whether ECG markers could be correlated with cardiac function abnormalities. We found that the C3H/HeN:JR combination frequently displayed early onset CCC indicators, such as sinus bradycardia and right bundle branch block, as well as prolonged PQ, PR, RR, ST, and QT intervals in the acute stage. Our model exhibited high levels of cardiac inflammation and enhanced iNOS expression in the acute stage, but denervation did not appear to have a role in pathology. These results demonstrate the potential of the C3H/HeN:JR host:parasite combination as a model for CCC that could be used for screening new compounds targeted at cardiac remodelling and for examining the potential of antiparasitic drugs to prevent or alleviate CCC development and progression.
Advances in Neuropathic Pain Research: Selected Intracellular Factors as Potential Targets for Multidirectional Analgesics
Authors: Ciapała Katarzyna , Mika Joanna
Published: November 2023

Neuropathic pain is a complex and debilitating condition that affects millions of people worldwide. Unlike acute pain, which is short-term and starts suddenly in response to an injury, neuropathic pain arises from somatosensory nervous system damage or disease, is usually chronic, and makes every day functioning difficult, substantially reducing quality of life. The main reason for the lack of effective pharmacotherapies for neuropathic pain is its diverse etiology and the complex, still poorly understood, pathophysiological mechanism of its progression. Numerous experimental studies, including ours, conducted over the last several decades have shown that the development of neuropathic pain is based on disturbances in cell activity, imbalances in the production of pronociceptive factors, and changes in signaling pathways such as p38MAPK, ERK, JNK, NF-κB, PI3K, and NRF2, which could become important targets for pharmacotherapy in the future. Despite the availability of many different analgesics, relieving neuropathic pain is still extremely difficult and requires a multidirectional, individual approach. We would like to point out that an increasing amount of data indicates that nonselective compounds directed at more than one molecular target exert promising analgesic effects. In our review, we characterize four substances (minocycline, astaxanthin, fisetin, and peimine) with analgesic properties that result from a wide spectrum of actions, including the modulation of MAPKs and other factors. We would like to draw attention to these selected substances since, in preclinical studies, they show suitable analgesic properties in models of neuropathy of various etiologies, and, importantly, some are already used as dietary supplements; for example, astaxanthin and fisetin protect against oxidative stress and have anti-inflammatory properties. It is worth emphasizing that the results of behavioral tests also indicate their usefulness when combined with opioids, the effectiveness of which decreases when neuropathy develops. Moreover, these substances appear to have additional, beneficial properties for the treatment of diseases that frequently co-occur with neuropathic pain. Therefore, these substances provide hope for the development of modern pharmacological tools to not only treat symptoms but also restore the proper functioning of the human body.
N-Succinylaspartic-Acid-Conjugated Riluzole Is a Safe and Potent Colon-Targeted Prodrug of Riluzole against DNBS-Induced Rat Colitis
Authors: Kim Jaejeong , Kang Changyu , Yoo Jin-Wook , Yoon In-Soo , Jung Yunjin
Published: November 2023

In our previous study, riluzole azo-linked to salicylic acid (RAS) was prepared as a colon-targeted prodrug of riluzole (RLZ) to facilitate the repositioning of RLZ as an anticolitic drug. RAS is more effective against rat colitis than RLZ and sulfasalazine, currently used as an anti-inflammatory bowel disease drug. The aim of this study is to further improve colon specificity, anticolitic potency, and safety of RAS. N-succinylaspart-1-ylRLZ (SAR) and N-succinylglutam-1-ylRLZ (SGR) were synthesized and evaluated as a “me-better” colon-targeted prodrug of RLZ against rat colitis. SAR but not SGR was converted to RLZ in the cecal contents, whereas both conjugates remained intact in the small intestine. When comparing the colon specificity of SAR with that of RAS, the distribution coefficient and cell permeability of SAR were lower than those of RAS. In parallel, oral SAR delivered a greater amount of RLZ to the cecum of rats than oral RAS. In a DNBS-induced rat model of colitis, oral SAR mitigated colonic damage and inflammation and was more potent than oral RAS. Moreover, upon oral administration, SAR had a greater ability to limit the systemic absorption of RLZ than RAS, indicating a reduced risk of systemic side effects of SAR. Taken together, SAR may be a “me-better” colon-targeted prodrug of RLZ to improve the safety and anticolitic potency of RAS, an azo-type colon-targeted prodrug of RLZ.
Aerogels as Carriers for Oral Administration of Drugs: An Approach towards Colonic Delivery
Authors: Illanes-Bordomás Carlos , Landin Mariana , García-González Carlos A.
Published: November 2023

Polysaccharide aerogels have emerged as a highly promising technology in the field of oral drug delivery. These nanoporous, ultralight materials, derived from natural polysaccharides such as cellulose, starch, or chitin, have significant potential in colonic drug delivery due to their unique properties. The particular degradability of polysaccharide-based materials by the colonic microbiota makes them attractive to produce systems to load, protect, and release drugs in a controlled manner, with the capability to precisely target the colon. This would allow the local treatment of gastrointestinal pathologies such as colon cancer or inflammatory bowel diseases. Despite their great potential, these applications of polysaccharide aerogels have not been widely explored. This review aims to consolidate the available knowledge on the use of polysaccharides for oral drug delivery and their performance, the production methods for polysaccharide-based aerogels, the drug loading possibilities, and the capacity of these nanostructured systems to target colonic regions.
Effects of Light Intensity on the Growth and Biochemical Composition in Various Microalgae Grown at High CO2 Concentrations
Authors: Chunzhuk Elizaveta A. , Grigorenko Anatoly V. , Kiseleva Sophia V. , Chernova Nadezhda I. , Vlaskin Mikhail S. , Ryndin Kirill G. , Butyrin Aleksey V. , Ambaryan Grayr N. , Dudoladov Aleksandr O.
Published: November 2023

In modern energy, various technologies for absorbing carbon dioxide from the atmosphere are being considered, including photosynthetic microalgae. An important task is to obtain maximum productivity at high concentrations of CO2 in gas–air mixtures. In this regard, the aim of the investigation is to study the effect of light intensity on the biomass growth and biochemical composition of five different microalgae strains: Arthrospira platensis, Chlorella ellipsoidea, Chlorella vulgaris, Gloeotila pulchra, and Elliptochloris subsphaerica. To assess the viability of microalgae cells, the method of cytochemical staining with methylene blue, which enables identifying dead cells during microscopy, was used. The microalgae were cultivated at 6% CO2 and five different intensities: 80, 120, 160, 200, and 245 μmol quanta·m−2·s−1. The maximum growth rate among all strains was obtained for C. vulgaris (0.78 g·L−1·d−1) at an illumination intensity of 245 µmol quanta·m−2·s−1. For E. subsphaerica and A. platensis, similar results (approximately 0.59 and 0.25 g·L−1·d−1 for each strain) were obtained at an illumination intensity of 160 and 245 µmol quanta·m−2·s−1. A decrease in protein content with an increase in illumination was noted for C. vulgaris (from 61.0 to 46.6%) and A. platensis (from 43.8 to 33.6%), and a slight increase in lipid content was shown by A. platensis (from 17.8 to 21.4%). The possibility of increasing microalgae biomass productivity by increasing illumination has been demonstrated. This result can also be considered as showing potential for enhanced lipid microalgae production for biodiesel applications.
Taxonomic Reinstatement of the Endemic Chinese Species Iris thoroldii (Iridaceae) from I. potaninii and Reassessment of I. zhaoana
Authors: Boltenkov Eugeny V.
Published: November 2023

Iris thoroldii is a perennial herbaceous plant with yellow, blue, or purple flowers. The species is native to the Tibetan Plateau and adjacent areas. In the literature and databases, I. thoroldii has long been treated in synonymy with I. potaninii. Currently, yellow-flowered plants of I. thoroldii are considered I. potanii, and blue-flowered plants are considered I. zhaoana, a replacement name for I. potaninii var. ionantha. This study aimed to clarify the taxonomic identity of I. thoroldii. A critical examination of original material, herbarium specimens, images of living plants, and the literature has shown I. thoroldii to be different from I. potaninii in some previously neglected macromorphological traits and to be conspecific with I. zhaoana. Thus, I. thoroldii is removed here from the synonymy of I. potaninii and accepted as a distinct species. This is endemic to China (central Gansu, Qinghai, and northwestern Sichuan provinces, and also Xinjiang Uygur and Tibet autonomous regions) and reaches the highest elevations compared with all other species in the genus Iris s.l. A revised taxonomy of I. thoroldii is provided, and two color forms, often co-occurring, are accepted: the autonymic yellow-flowered form (including a new synonym I. tigridia var. flavescens for which a lectotype was designated) and a form with blue or purple colors is proposed here, I. thoroldii f. ionantha. In addition, images of type specimens and detailed photographs of living plants for easy identification, along with the list of specimens of I. thoroldii that were examined, and also, comments on its distribution and habitats are provided.
Is Sellaphora the New Navicula? Cymbosellaphora (Cymbellales), a New Genus Based on Taxa Previously Assigned to Sellaphora
Authors: Kulikovskiy Maxim S. , Glushchenko Anton M. , Genkal Sergei I. , Kuznetsova Irina V. , Maltsev Yevhen I. , Kociolek John Patrick
Published: November 2023

A new diatom genus Cymbosellaphora Kulikovskiy, Glushchenko, Genkal and Kociolek gen. nov., was described with species Cymbosellaphora vietnamensis Glushchenko, Kulikovskiy and Kociolek sp. nov. C. vietnamensis sp. nov. was described from Vietnam and characterized by the presence of morphological features such as valves with naviculoid symmetry, slight dorsiventrality, the presence of tectula as pore occlusions, uniseriate striae, and a very broad mantle. Four species were transferred to the new genus. These are C. absoluta comb. nov., C. circumborealis comb. nov., C. geisslerae comb. nov., and C. laterostrata comb. nov. Previously, these species were members of genera Navicula Bory, Sellaphora Mereschkowsky, and Naviculadicta Lange-Bertalot. The taxonomic history of these species and genera are discussed. The tectulum is known only from the cymbelloid diatoms, and our new genus is placed within the Cymbellaceae. The presence of a tectulum demonstrates that these species cannot be placed in Sellaphora, as indicated in the literature. The recent proposal to transfer a large number of species with different morphologies to the genus Sellaphora is also discussed. Additionally, we compare pore occlusions with tectula between different genera of the Cymbellaceae with naviculoid symmetry.
A Novel Fused SiO2 and h-BN Modified Quartz Fiber/Benzoxazine Resin Ceramizable Composite with Excellent Flexural Strength and Ablation Resistance
Authors: Deng Zongyi , Lv Yunfei , Shi Minxian , Huang Zhixiong , Huang Wenchao
Published: November 2023

Hypersonic vehicles encounter hostile service environments of thermal/mechanical/chemical coupling, so thermal protection materials are crucial and essential. Ceramizable composites have recently attracted intensive interest due to their ability to provide large-area thermal protection for hypersonic vehicles. In this work, a novel ceramizable composite of quartz fiber/benzoxazine resin modified with fused SiO2 and h-BN was fabricated using a prepreg compression molding technique. The effects of the fused SiO2 and h-BN contents on the thermal, mechanical, and ablative properties of the ceramizable composite were systematically investigated. The ceramizable composite with an optimized amount of fused SiO2 and h-BN exhibited superb thermal stability, with a peak degradation temperature and residue yield at 1400 °C of 533.2 °C and 71.5%, respectively. Moreover, the modified ceramizable composite exhibited excellent load-bearing capacity with a flexural strength of 402.2 MPa and superior ablation resistance with a linear ablation rate of 0.0147 mm/s at a heat flux of 4.2 MW/m2, which was significantly better than the pristine quartz fiber/benzoxazine resin composite. In addition, possible ablation mechanisms were revealed based on the microstructure analysis, phase transformation, chemical bonding states, and the degree of graphitization of the ceramized products. The readily oxidized pyrolytic carbon (PyC) and the SiO2 with a relatively low melting point were converted in situ into refractory carbide. Thus, a robust thermal protective barrier with SiC as the skeleton and borosilicate glass as the matrix protected the composite from severe thermochemical erosion and thermomechanical denudation.
Influence of Processing Conditions on the Generation of Surface Defects in a Heat-and-Cool Hybrid Injection Molding Technique for Carbon Fiber-Reinforced Thermoplastic Sheets and Development of a Suitable Mold Heated by Far-Infrared Radiation
Authors: Murata Yasuhiko , Machiya Ryunosuke , Komori Takuma
Published: November 2023

Recently, hybrid injection molding—a type of overmolding technology in which a short carbon fiber-reinforced thermoplastic is injection molded over a compression-molded carbon fiber-reinforced thermoplastic (CFRTP) sheet—has been introduced. A heat-and-cool hybrid injection molding technique has also been introduced for practical use. The technique yields high-quality molded products. This is achieved through the heating of the mold cavity surface to a temperature higher than the melting point of the base polymer impregnated into the carbon fiber fabric. However, few experimental analyses of the molding phenomena in heat-and-cool hybrid injection molding have been reported. In particular, the effect of the processing conditions on the transfer of the mold cavity surface shape to the CFRTP sheet has not been clarified in detail. Therefore, it has been impossible to take extensive measures when defects are generated in molded products. In this study, a mold is designed and fabricated for use with far-infrared radiation heating, a variotherm technology that is suitable for the experimental analysis of the heat-and-cool hybrid injection molding phenomenon. In particular, a mold is designed and fabricated to continuously perform the following three processes using only an injection molding machine: (1) the radiation heating of both the CFRTP sheet and the mold cavity surface using a far-infrared radiation heater, (2) the compression molding of the CFRTP sheet, and (3) the injection molding of the melt. The effects of the heating conditions of the mold and the injection molding process conditions on the appearance characteristics of the molded products are clarified using this mold and a far-infrared radiation heater.
Magnetic Resonance-Based Analytical Tools to Study Polyvinylpyrrolidone–Hydroxyapatite Composites
Authors: Petrova Alina , Mamin Georgy , Gnezdilov Oleg , Fadeeva Inna , Antonova Olga , Forysenkova Anna , Antoniac Iulian V. , Rau Julietta V. , Gafurov Marat
Published: November 2023

The synthesis of biocompatible and bioresorbable composite materials, such as a “polymer matrix-mineral constituent,” stimulating the natural growth of living tissues and the restoration of damaged parts of the body, is one of the challenging problems in regenerative medicine and materials science. Composite films of bioresorbable polymer of polyvinylpyrrolidone (PVP) and hydroxyapatite (HA) were obtained. HA was synthesized in situ in the polymer solution. We applied electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) approaches to study the composite films’ properties. The application of EPR in two frequency ranges allowed us to derive spectroscopic parameters of the nitrogen-based light and radiation-induced paramagnetic centers in HA, PVP and PVP-HA with high accuracy. It was shown that PVP did not significantly affect the EPR spectral and relaxation parameters of the radiation-induced paramagnetic centers in HA, while light-induced centers were detected only in PVP. Magic angle spinning (MAS) 1H NMR showed the presence of two signals at 4.7 ppm and −2.15 ppm, attributed to “free” water and hydroxyl groups, while the single line was attributed to 31P. NMR relaxation measurements for 1H and 31P showed that the relaxation decays were multicomponent processes that can be described by three components of the transverse relaxation times. The obtained results demonstrated that the applied magnetic resonance methods can be used for the quality control of PVP-HA composites and, potentially, for the development of analytical tools to follow the processes of sample treatment, resorption, and degradation.
Additive Manufactured Parts Produced Using Selective Laser Sintering Technology: Comparison between Porosity of Pure and Blended Polymers
Authors: Morano Chiara , Pagnotta Leonardo
Published: November 2023

For different manufacturing processes, porosity occurs in parts made using selective laser sintering (SLS) technology, representing one of the weakest points of materials produced with these processes. Even though there are different studies involving many polymeric materials employed via SLS, and different manuscripts in the literature that discuss the porosity occurrence in pure or blended polymers, to date, no researcher has reported a systematic and exhaustive comparison of the porosity percentage. A direct comparison of the available data may prove pivotal in advancing our understanding within the field of additively manufactured polymers. This work aims to collect and compare the results obtained by researchers who have studied SLS’s applicability to different amorphous or semi-crystalline polymers and pure or blended materials. In particular, the porosity values obtained by different researchers are compared, and tables are provided that show, for each material, the process parameters and the measured porosity values.
Hair-Reinforced Elastomer Matrix Composites: Formulation, Mechanical Testing, and Advanced Microstructural Characterization
Authors: Statnik Eugene S. , Cvjetinovic Julijana , Ignatyev Semen D. , Wassouf Loujain , Salimon Alexey I. , Korsunsky Alexander M.
Published: November 2023

Epoxy matrix composites reinforced with high-performance fibers, such as carbon, Kevlar, and glass, exhibit excellent specific stiffness and strength in many mechanical applications. However, these composites are disappointingly non-recyclable and are usually disposed of in landfill sites, with no realistic prospect for biodegradation in a reasonable time. In contrast, moldable composites with carbonized elastomeric matrices developed in the last decades possess attractive mechanical properties in final net-shape products and can also be incinerated or recycled. Many carbon and inorganic fillers have recently been evaluated to adjust the properties of carbonized elastomeric composites. Renewable organic fillers, such as human or animal hair, offer an attractive fibrous material with substantial potential for reinforcing composites with elastomeric matrices. Samples of unidirectional fiber composites (with hair volume fractions up to 7%) and quasi-isotropic short fiber composites (with hair volume fractions up to 20%) of human hair-reinforced nitrile butadiene rubbers (HH-NBRs) were produced in the peroxide-cured and carbonized states. The samples were characterized using scanning electron microscopy (SEM), Raman spectroscopy, and photoacoustic microscopy. Mechanical tests were performed under tension using a miniature universal testing machine. The expected effect of fiber reinforcement on the overall mechanical performance was demonstrated for both cured and carbonized composites. Considerable enhancement of the elastic modulus (up to ten times), ultimate tensile strength (up to three times), and damage tolerance was achieved. The evidence of satisfactory interfacial bonding between hair and rubber was confirmed via SEM imaging of fracture surfaces. The suitability of photoacoustic microscopy was assessed for 3D reconstructions of the fiber sub-system’s spatial distribution and non-destructive testing.
Effect of Heat Treatment Process on Microstructure and Mechanical Properties of High-Carbon H13 Steel
Authors: Du Kunda , Lv Zhifeng , Fan Weichao , Zhang Ruikong , Li Xuexian , Xu Lipeng
Published: November 2023

This paper investigated the mechanical properties and microstructures of different samples of H13 steel after they underwent various heat treatment processes. It provided a detailed analysis of the microstructure and mechanical properties under different processes and approached the topic from a theoretical perspective. The phase composition of each sample remained unchanged after undergoing different heat treatment processes. Despite the vacuum gas quenching (H1) sample being guaranteed a hardness of 58.47 HRC, its toughness fell below expectations at a mere 46.75 J. Notably, the microstructure of the sample which underwent the H1 process and the cryogenic (H2) treatment exhibited a finer grain size and higher toughness compared to the sample which only underwent the H1 process without the cryogenic treatment. Its toughness was 70.19 J, but its hardness slightly decreased to 57.47 HRC. Following the application of oil quenching and cryogenic treatment (H3), the hardness of the sample significantly increased, reaching a remarkable 58.38 HRC. Additionally, the sample exhibited good impact resistance, with a measurement of 74.25 J. Before the H2 process, the sample which underwent the spheroidizing annealing process (H4) had a higher hardness compared to the sample without spheroidizing annealing. At the same time, when comparing the above four samples, the sample that underwent the H4 process exhibited the best toughness, with a value of 86.94 J, while still maintaining a hardness of 57.85 HRC; thus, it achieved an ideal balance between strength and toughness. Therefore, the optimal heat treatment process for high-carbon H13 steel was spheroidizing annealing followed by vacuum gas quenching and then cryogenic treatment.
Maximum Power Point Tracking Constraint Conditions and Two Control Methods for Isolated Photovoltaic Systems
Authors: Fan Jingxun , Li Shaowu , Liu Sanjun , Deng Xiaoqing , Zhu Xianping
Published: November 2023

A maximum power point (MPP) always exists in photovoltaic (PV) cells, but a mismatch between PV system circuit parameters, weather conditions and system structure leads to the possibility that the MPP may not be tracked successfully. In addition, the introduction of an isolation transformer into a basic PV system allows for moderate values of the converter duty cycle and electrical isolation. However, there is no comprehensive research on MPPT (maximum power point tracking) constraint conditions for different isolated PV systems, which seriously hinders the application of isolated PV systems and the development of a related linear control theory. Therefore, in this paper, the overall mathematical models of different isolated PV systems are first established based on the PV cell engineering model and the MPP linear model, and then, two sets of constraint conditions are found for the successful realization of MPPT. These MPPT constraint conditions (MCCs) describe in detail the direct mathematical relationships between PV cell parameters, weather conditions and circuit parameters. Finally, based on the MPP linear model and MCCs, two new MPPT methods are designed for isolated PV systems. Considering the MCCs proposed in this paper, a suitable range of load and transformer ratios can be estimated from the measured data of irradiance and temperature in a certain area, and the range of MPPs existing in PV systems with different structures can be estimated, which is a good guide for circuit design, theoretical derivation and product selection for PV systems. Meanwhile, comparative experiments confirm the rapidity and accuracy of the two proposed MPPT methods, with the MPPT time improving from 0.23 s to 0.03 s, and they have the advantages of a simple program, small computational volume and low hardware cost.
Subjective Effects of a Single Dose of Ayahuasca among College Students with Harmful Alcohol Use: Qualitative Analysis of Participant Accounts
Authors: Vicentini Anna Beatriz , Rodrigues Lucas Silva , Rossi Giordano Novak , Rocha Juliana Mendes , Guerra Lorena T. L. , Reis José Augusto Silva , Maekawa Renan Massanobu , Osório Flávia de Lima , Bouso José Carlos , Santos Fabiana Pereira , Paranhos Beatriz Aparecida Passos Bismara , Yonamine Mauricio , Hallak Jaime Eduardo Cecilio , dos Santos Rafael Guimarães
Published: November 2023

Alcohol is the recreational drug most frequently consumed, and its high frequency of use can lead to worsening social, psychological, and domestic issues. The age group most susceptible to alcohol dependence is 18- to 24-year-old youths, demanding interventional tools to target early involvement risks. Ayahuasca seems to be a promising therapeutic tool since evidence suggests it presents potential for the treatment of depression, anxiety, and substance abuse, among other disorders. This study aimed to analyze subjective reports of university students with harmful alcohol use participating in a single-blind study evaluating the effects of one ayahuasca dose (1 mL/kg). Twenty-one days after ayahuasca administration, semi-structured interviews were conducted (n = 6) to identify peer psychological elements linked to its therapeutic potential. Subsequently, content analysis methodology was employed to define the main categories: Self-perception of experience, Positive Impacts (PI), Substances Use Pattern (SUP), Insights (I), Visual Effects, Transient Derealization, and Sleep Pattern. Among these, the most pertinent categories for this study were PI, SUP, and I, as, together, they suggest a potential link between insights and/or positive emotions and reduced alcohol consumption due to their internal transformation potential, which could be linked to a decrease in consumption.
The Impact of the Loss of a Child in the Prenatal Period on Marital and Family Life and the Religiosity of Women after Miscarriage
Authors: Kłos-Skrzypczak Aleksandra
Published: November 2023

Experiencing the death of a child is one of the most difficult things a person can go through. The situation of parents who have lost a child during the prenatal period is burdened with a social taboo. In the public sphere, it is often referred as the “secret problem of women”. The aspect of religiosity is extremely important in experiencing mourning after a miscarriage. The study is of a theoretical–empirical nature. The purpose of this text is to emphasize the value of human life at every stage, including in the situation of miscarriage. Online questionnaire research was conducted on a sample of 77 women, supplemented by content analysis of three of the most popular virtual support groups for parents who have experienced child loss in Poland. The aim of the conducted research was to attempt to illustrate how women cope with the experience of miscarriage and how this experience affects marital and family relationships. The issue of faith and the depth of religious life were highlighted as elements that provide support to parents after miscarriage at various stages of mourning.
An Inverse-Occurrence Sampling Approach for Urban Flood Susceptibility Mapping
Authors: Wang Changpeng , Lin Yangchun , Tao Zhiwen , Zhan Jiayin , Li Wenkai , Huang Huabing
Published: November 2023

Data-driven flood susceptibility modeling is an efficient way to map the spatial distribution of flood likelihood. The quality of the flood susceptibility model relies on the learning technique and the data used for learning. The performance of learning techniques has been extensively examined. However, to date, the impact of data sampling strategies has received limited attention. Random sampling is widely favored because of its ease of use. It treats flood-related data as tabular and excludes their spatial dimensions. Flood occurrence is typically uneven over space. Therefore, non-flood sampling should not be completely random. To represent the impact of the spatial dimension, this study proposed a new sampling approach based on spatial dependence, called inverse-occurrence sampling. It selects more non-flood data in low-risk areas than in high-risk areas. The new sampling approach was compared with random and stratified sampling, using six machine learning techniques in two urban areas in Guangzhou, China, with distinct flood mechanisms, that is, Tianhe (flood density 1.5/km2, clustered distribution, average slope 9.02°, downtown district) and Panyu (flood density 0.15/km2, random distribution, average slope 4.55°, suburban district). Learning techniques include support vector machine (SVM), random forest (RF), artificial neural networks (ANNs), convolutional neural networks (CNNs), CNN-SVM, and CNN-RF. The main findings of this study were as follows: (1) Sampling approaches had a greater impact on model performance than learning techniques in terms of area under the receiver operating characteristic curve (AUC). The AUC variations caused by learning techniques ranged from 0.04 to 0.09. Meanwhile, the AUC variations caused by sampling approaches were between 0.15 and 0.22, all larger than 0.1. (2) The new sampling approach outperformed that of the other two sampling approaches for high average AUC values and small AUC variations. The outperformance is robust in regard to multiple learning techniques and different flooding mechanisms. AUCs in the inverse group had a narrower range (0.14–0.18 in Tianhe and 0.35–0.39 in Panyu) than in the random group (0.24–0.28 in Tianhe and 0.43–0.53 in Panyu) and the stratified group (0.23–0.30 in Tianhe and 0.42–0.48 in Panyu). (3) The most accurate learning technique for AUC was CNN-RF, followed by SVM, CNN-SVM, RF, CNN, and ANN. (4) ANN- and CNN-based models tended to produce polarized patterns in flood susceptibility maps, contradicting the ascending order of flood density with increasing susceptibility levels. Flood density outliers tended to appear in the models derived using RF and CNN-RF. Finally, the newly proposed sampling approach is suggested to be applied to flood susceptibility mapping to reflect the impact of spatial dependence.