Types Of Mats Research Articles

Maturation of human cardiomyocytes derived from induced pluripotent stem cells (iPSC-CMs) on polycaprolactone and polyurethane nanofibrous mats

Investigating the potential of human cardiomyocytes derived from induced pluripotent stem cells (iPSC-CMs) in in vitro heart models is essential to develop cardiac regenerative medicine. iPSC-CMs are immature with a fetal-like phenotype relative to cardiomyocytes in vivo. Literature indicates methods for enhancing the structural maturity of iPSC-CMs. Among these strategies, nanofibrous scaffolds offer more accurate mimicry of the functioning of cardiac tissue structures in the human body. However, further research is needed on the use of nanofibrous mats to understand their effects on iPSC-CMs. Our research aimed to evaluate the suitability of poly(ε-caprolactone) (PCL) and polyurethane (PU) nanofibrous mats with different elasticities as materials for the maturation of iPSC-CMs. Analysis of cell morphology and orientation and the expression levels of selected genes and proteins were performed to determine the effect of the type of nanofibrous mats on the maturation of iPSC-CMs after long-term (10-day) culture. Understanding the impact of 3D structural properties in in vitro cardiac models on induced pluripotent stem cell-derived cardiomyocyte maturation is crucial for advancing cardiac tissue engineering and regenerative medicine because it can help optimize conditions for obtaining more mature and functional human cardiomyocytes.

Stimulated Full-Thickness Cutaneous Wound Healing with Bioactive Dressings of Zinc and Cobalt Ion-Doped Bioactive Glass-Coated Eggshell Membranes in a Diabetic Rabbit Model.

Eggshell membrane-based biomedical applications have recently received great attention for their wound-healing properties. However, there are limited studies on diabetic wound healing. In this regard, we devised four types of composite eggshell membrane mats with nanoscale coatings of bioactive glass/Zn/Co-doped bioactive glass (ESM + BAG, ESM + ZnBAG, ESM + CoBAG, and ESM + ZnCoBAG) as wound-dressing materials for chronic nonhealing diabetic wounds. A detailed study of the physicochemical properties of the mats was conducted. In vitro studies demonstrated cytocompatibility and viability of human dermal fibroblasts on all four types of mats. The cells also attached finely on the mats with the help of cellular extensions, as evident from scanning electron microscopy (SEM) and rhodamine-phalloidin and Hoechst 33342 staining of cellular components. Endowed with bioactive properties, these mats influenced all aspects of full-thickness skin wound healing in diabetic animal model studies. All of the mats, especially the ESM + ZnCoBAG mat, showed the earliest wound closure, effective renewal, and restructuring of the extracellular matrix in terms of an accurate and timely accumulation of collagen, elastin, and reticulin fibers. Hydroxyproline and sulfated glycosaminoglycans were significantly (p < 0.01, p < 0.05) higher in ESM-ZnCoBAG-treated wounds in comparison to ESM-BAG-treated wounds, which suggests that these newly developed mats have potential as an affordable diabetic wound care solution in biomedical research.

Microbial mat-induced microfacies in clastic deposits – An overview

Abstract This contribution reviews microbial microfacies recognisable in vertical sections through modern or fossil mat-overgrown sediment. Microfacies are products of endobenthic or epibenthic microbial mats interacting with sediment dynamics. Laminae of such mats form during sediment dynamic quiescence by organisation of filaments to an interwoven mat fabrics (binding), and biomass enrichment (growth) by cell replication and the production of extracellular polymeric substances (EPS). Vertical sections through mat-covered sediment may show buried stacks of subrecent mat laminae (biolaminites) that rose from alternating periods of mat development and sediment deposition. Mat laminae that drape ripple marks are visible as sinoidal structures in sediment core or sections. If the sediment-stabilising properties of a microbial mat is overcome by currents or waves of high strengths, cm-size mat fragments (mat chips and roll-ups) are ripped off and redeposited. Intrasedimenary gases, trapped beneath mat layers, may cause a high secondary porosity (sponge pore sand) in the sandy substrates. The internal build-up (microfabrics) of mat laminae is investigated under high magnification. Endobenthic microbial mat fabrics include filamentous and coccoid cells forming a network, EPS, and sedimentary grains. The grains derived from interaction of the endobenthic mats with bed load. Epibenthic microbial mat fabrics may include also silt-size particles syndepositionally enriched by baffling and trapping of suspension load. The fabrics of these mats commonly also include oriented sedimentary grains. These grains (now aligned bedding parallel) were dragged upward from the substrate during the development and growth of the mat. Overall, microbial microfacies provide insight into the sedimentation pattern of the (paleo-)environment and into the types of the substrate-colonising microbial mats.

And now for something completely random: spatial distribution of Dickinsonia on the Ediacaran seafloor

The oldest evidence of motile complex benthic multicellular organisms is found in Ediacaran aged rocks. At Nilpena Ediacara National Park (NENP), South Australia, one of the most iconic of such organisms, Dickinsonia, are found in abundance, with over 500 individuals preserved across the site's 33 in situ, fossiliferous beds. These beds vary in mat type and maturity, community diversity and population size. Here, we investigate six beds using spatial point pattern analysis (SPPA) to compare Dickinsonia spatial distributions between populations. Five populations were best-fit to a completely spatially random pattern, with a single outlier (TC-MM3) exhibiting signs of environmental heterogeneity. When distributions were examined in relation to other taxa, no indication of spatial competition was detected. Univariate and bivariate spatial distributions imply that Dickinsonia was generally not impacted by competition with other taxa, meter-scale environmental heterogeneity, or other external factors. These patterns hold when analyses were split between populations of large and small individuals, and these two size cohorts had no measurable effect on each other's spatial distributions. Additionally, we find no indication of intraspecific competition for Dickinsonia or any change in the preferred resources or habitats with growth. These results suggest that the anactualistic environmental conditions produced by ubiquitous organic mats present across Ediacaran seafloors at NENP provided such abundant nutrients that Dickinsonia did not have to compete for resources at the meter scale. These results further inform community-scale dynamics of Earth's earliest complex ecosystem.

Retrofitting of severely damaged RC beams using novel bio-composite-based mat-matrix system

Due to the rapid urbanization and boom in the infrastructure sector, the frequency of repair and retrofitting in major structures has significantly increased in recent times. Hence, it is essential to adopt a repair/retrofit strategy that not only improves the load-carrying capacity but is also ductile, durable, and cost-effective. In this study, efforts are put forth to develop a novel bio-composite-based mat-matrix strengthening system for restoring the overall performance of severely damaged reinforced concrete (RC) beams. In total, eight full-scale RC beams of span 2.2 m were tested under two different shear span (av) to effective depth (d) ratios of 5.0 and 3.9 to understand the efficiency of proposed strengthening schemes under flexure and shear load combinations. The initial loading of RC beams (i.e. damage phase) showed intense opening of tension cracks in the constant moment zone and crushing at the compression face of the beam. After failure, all the beams were surface prepared and retrofitted with the novel bio-composite mat-matrix system using different combinations of bi-directional flax/hemp fiber mat and discrete flax/hemp fiber based UHTCC matrix. The parameters investigated include (i) type of bio-fiber mat, (ii) type of discrete bio-fiber in UHTCC matrix, and (iii) shear span (av) to effective depth (d) ratio. Results revealed that the proposed composite system was able to completely restore the overall performance of severely damaged RC beams at low av/d ratios. However, in the case of beams with flexure-dominant failure (high av/d), the strengthening system was able to restore about 90% of the ultimate load.

Domains in Action: Understanding Ddi1's Diverse Functions in the Ubiquitin-Proteasome System.

The ubiquitin-proteasome system (UPS) is a pivotal cellular mechanism responsible for the selective degradation of proteins, playing an essential role in proteostasis, protein quality control, and regulating various cellular processes, with ubiquitin marking proteins for degradation through a complex, multi-stage process. The shuttle proteins family is a very unique group of proteins that plays an important role in the ubiquitin-proteasome system. Ddi1, Dsk2, and Rad23 are shuttle factors that bind ubiquitinated substrates and deliver them to the 26S proteasome. Besides mediating the delivery of ubiquitinated proteins, they are also involved in many other biological processes. Ddi1, the least-studied shuttle protein, exhibits unique physicochemical properties that allow it to play non-canonical functions in the cells. It regulates cell cycle progression and response to proteasome inhibition and defines MAT type of yeast cells. The Ddi1 contains UBL and UBA domains, which are crucial for binding to proteasome receptors and ubiquitin respectively, but also an additional domain called RVP. Additionally, much evidence has been provided to question whether Ddi1 is a classical shuttle protein. For many years, the true nature of this protein remained unclear. Here, we highlight the recent discoveries, which shed new light on the structure and biological functions of the Ddi1 protein.

Parameters influencing electrospun nanofiber diameter of polylactide incorporated with cellulose nanofibrils and nanocrystals

The main purpose of this study was to investigate effects of various electrospinning parameters on the morphology and diameter of cellulose nanofibril (CNF) filled polylactide (PLA) nanofibers. For this purpose, first of all effects of three important electrospinning parameters; polymer solution concentration, solution feeding rate and collector distance to feeding tip were studied. Then, effects of using higher amount of CNF, effects of using cellulose nanocrystal (CNC) particles, and effects of adding potassium chloride salt were also investigated. It was observed that when optimum electrospinning parameters were determined, then it was possible to obtain almost “bead-free” morphology and “finest” average diameter of 232 nm for PLA/CNF electrospun fibers. Increasing values of feeding rate and collector distance parameters resulted in bead formation and thicker diameters. On the other hand, increasing CNF amount, using CNC particles and adding KCl salt, all resulted in further decreases in the diameter down to 152 nm; mainly due to increased charge density of the polymer solution. Moreover, in vitro degradation analysis of all types of electrospun nanofiber mats in a simulated body fluid revealed that increasing the immersion period increased their degradation rate in terms of “% weight loss”. It was also observed that, mats with fine diameter fibers had higher degradation rate.

Characterization and prediction of tensile properties of carbon fiber-reinforced thermoplastics composed of hybrid short carbon fiber/PA6 fiber nonwoven mats

Hybrid carbon fiber/resin fiber nonwoven mats are considered as a highly promising application of recycled carbon fibers due to their low cost and simple synthesis process. However, the mechanical properties of hybrid nonwoven mats are subject to uncertainties due to nonuniformity of fiber orientations during production procedures, which restricts their use in structural components. This study investigates the characteristics of various types of hybrid nonwoven mats with different volume fractions and fiber orientation distributions. Notably, the investigation yields noteworthy tensile properties, exemplified by a tensile strength of 367.20 MPa and a stiffness of 32.85 GPa, when the volume fraction is 28.9%. Tensile properties of the hybrid nonwoven mats and their fluctuations are then analyzed through statistical analyses. A three-dimensional microstructure-based fiber network model is established using the Monte Carlo method to represent the statistical and stochastic properties of the material. Furthermore, a prediction method of tensile properties based on microstructural properties in the model is proposed, which shows good agreement with all experimental results for adjustments of the volume fraction of carbon fibers, distribution of fiber lengths, and anisotropy of the materials, significantly reducing the experimental burden for optimization research. The tensile characteristics of composites are reliably anticipated with a nominal error margin below 10%. Additionally, this prediction method enables the prediction of scatter and stable standard deviation, making it possible to apply hybrid nonwoven mats in recycling and industrial processes.

Impact Sound Reduction Performances of Additional Floor Mats for the Retrofitting of an Existing Apartment Building in Accordance with Test-Bed Conditions

Floor mats are commonly used to improve the impact sound performance of existing homes, but actual impact sound reductions do not consistently appear, as they depend on the test-bed conditions used to determine impact sound performance. Therefore, this study evaluated the effects of the environmental conditions of the test bed on the impact sound reduction performances of different floor mats. The Korean industrial standard KS F 2865 specifies the measurement method in the test room and sets the thickness range of the available target floor structure to bare slabs with thicknesses ranging from 120 mm to 210 mm. The evaluation method is ∆L, which is the difference in standardized impact sound levels before and after the installation of the floor finishing material. In this study, a total of eight types of floor mats were tested in four different test beds according to KS F 2865. The impact sources used were tapping, bang machines, and a rubber ball, and we used these sources to consider both light-weight and heavy-weight impact sounds. The results were derived as the impact sound reduction performance for each frequency band and a single-number quantity. The results showed that light impact sound had a similar minimum reduction characteristic of at least 38 dB, regardless of the floor structure on which the mat was installed. However, the heavy-weight impact sound showed different tendencies depending on the floor mat and the characteristics of the floor structure of the test bed when a bang machine and a rubber ball were used. In particular, the reduction achieved by the bang machine showed less than half the tendency of the reduction by the rubber ball, and the tendency of the heavy-weight impact sound was shown to be reducible depending on how the floor mat was maintained, but the reductions differed depending on the test bed. The reductions were larger in the box-type test room than in the real-life-type test room, and among the box-type test rooms, the one with a thicker bare slab showed a relatively larger reduction. In addition, the reliability of the measurement results was evaluated through a correlation analysis between the single-number quantities depending on the thicknesses of the bare slabs of the test beds.

Effects of intercropping on soil greenhouse gas emissions - A global meta-analysis

Diversified cropping systems, such as intercropping, have shown multifunctionality in agronomic productivity promotion, pest control, and soil health improvement. However, the intense interaction between crop species stimulates soil carbon and nitrogen turnover, and intercropping systems cause inexplicit effects on soil greenhouse gas emissions (GHG). Therefore, a comprehensive meta-analysis using 52 published articles (531 paired observations) was conducted to elucidate the effects of intercropping on soil N2O, CO2, and CH4 emissions under different environmental conditions and field practices to identify the primary driving factors, such as climate, soil and field practices. The results showed that intercropping treatment had a non-significant impact on the three GHG emissions on average. However, using a cereal-legume intercropping regime, adopting moderate N application rate or intercropping in alkaline soils could significantly mitigate soil N2O emission. Additionally, intercropping in soils with high soil organic carbon reduce soil CH4 emission. On the contrary, increasing intercropping duration, or adopted in soils with moderate soil total N tended to stimulate CO2 emission. The mixed-effect model selection indicated that initial soil pH, MAP, MAT, tillage regime, and intercropping duration and type were significant moderators in regulating soil GHG emissions. Our findings explicitly elucidated soil GHG responses to intercropping practice. Further studies are warranted on the evaluation of long-term intercropping effects to improve the comprehensive understanding of C and N balance and global warming potential under intercropping.

Bilayer nanofibers loaded with Malva sylvestris extract for enhanced wound healing applications

Addressing the challenges of wound care requires accurate dressing selection. The combination of collagen with nanofibers (NFs) enhances its properties, improving cellular recognition. Multi-layered nanofibrous systems, particularly those with Polycaprolactone (PCL), offer higher mechanical attributes and prolonged substance release. We fabricated four types of nanofibrous bilayer mats (NBMs) using electrospinning (EN), each composed of an active layer containing a mixture of PCL and collagen loaded with and without Malva sylvestris (MS) extract, and an inactive layer with only PCL. The resulting bilayers were neat PCL/PCL-Collagen (PCLC), PCL/PCLC-5% MS, PCL/PCLC-10% MS, and PCL/PCLC-15% MS. Morphological and mechanical properties, porosity, water vapor transmission rate (WVTR), swelling rates, drug release profiles, cytotoxicity, cell attachment, and cytoprotective effect of bilayers were evaluated. FE-SEM imaging revealed smooth and filamentous mats without any beads, with Fiber diameter average (FDA) ranging from 128 ± 41 nm to 140 ± 51 nm. WVTR values of the NFs were comparable to commercial dressings like Tegaderm, Bioclusive, and Op Site. The mats demonstrated significant liquid uptake capacity, indicating their potential to handle wound exudate. They exhibited prolonged extract release, ensuring a sustained supply. All mats showed excellent blood compatibility, with our MS-loaded NBMs displaying rapid blood clotting times, essential for effective wound closure. FE-SEM images confirmed robust cell adhesion and spreading on both loaded and unloaded mats. The study underscored the potent cytoprotective effects of MS extract, in both free and encapsulated forms. The dose-dependent increase in cell viability suggests its potential in mitigating oxidative stress-induced cellular damage. The MTT (4,5-dimethyl- 2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) assay revealed that encapsulating MS extract in bilayer NFs significantly improved cell viability at 48 and 72 h, surpassing free MS extract treatment.

How to Defeat Multidrug-Resistant Bacteria in Intensive Care Units. A Lesson from the COVID-19 Pandemic. Prevention, Reservoirs, and Implications for Clinical Practice.

Background: Intensive care unit (ICU) patients are at high risk of infection due to multiple invasive procedures, malnutrition, or immunosuppression. The rapid increase in infections with multidrug-resistant organisms (MDRO) during the COVID-19 pandemic caused a dilemma, as the rules of the sanitary regime in ICU rooms were strictly adhered to in the prevailing epidemiological situation. The combat to reduce the number of infections and pathogen transmission became a priority for ICU staff. This study aimed to assess whether eliminating environmental reservoirs and implementing improved procedures for patient care and decontamination and washing equipment in the ICU reduced the incidence of infections caused by MDR strains. Material and methods: The study retrospectively analyzed data in the ICU during the COVID-19 pandemic. The samples were collected based on microbiological culture and medical records in the newly opened ICU (10 stations) and hospital wards where COVID-19 patients were hospitalized. Environmental inoculations were performed during the COVID-19 pandemic every 4-6 weeks unless an increase in the incidence of infections caused by MDR strains was observed. Through microbiological analysis, environmental reservoirs of MDR pathogens were identified. The observation time was divided into two periods, before and after the revised procedures. The relationship between isolated strains of Klebsiella pneumoniae NDM from patients and potential reservoirs within the ICU using ERIC-PCR and dice methods was analyzed. Results: An increased frequency of infections and colonization caused by MDRO was observed compared to the preceding years. A total of 23,167 microbiological tests and 6,985 screening tests for CPE and MRSA bacilli were collected. The pathogen spread was analyzed, and the findings indicated procedural errors. Assuming that the transmission of infections through the staff hands was significantly limited by the restrictive use of personal protective equipment, the search for a reservoir of microorganisms in the environment began. MDR strains were grown from the inoculations collected from the hand-wash basins in the wards and from inside the air conditioner on the ceiling outside the patient rooms. New types of decontamination mats were used in high-risk areas with a disinfectant based on Glucoprotamine. Active chlorine-containing substances were widely used to clean and disinfect surfaces. Conclusions: Infections with MDR strains pose a challenge for health care. Identification of bacterial reservoirs and comprehensive nursing care significantly reduce the number of nosocomial infections.

Enhancing mechanical performance of TiO2 filler with Kevlar/epoxy-based hybrid composites in a cryogenic environment: a statistical optimization study using RSM and ANN methods

This research aims to investigate the mechanical performance of the different weight proportions of nano-TiO2 combined with Kevlar fiber-based hybrid composites under cryogenic conditions. The following parameters were thus considered: (i) Kevlar fiber mat type (100 and 200 gsm); (ii) weight proportions of TiO2 nanofiller (2 and 6 wt%); and (iii) cryogenic processing time (10–30 min at −196°C). The composites were fabricated through compression molding techniques. After fabrication, the mechanical characteristics of the prepared nanocomposites—such as tensile, bending, and impact properties—were evaluated. The optimal mechanical strength of nanofiller-based composites was analyzed using response surface methodology (RSM) and artificial neural networks (ANNs). Compositions, such as four weight percentages of nano-TiO2 filler, 200 gsm of the Kevlar fiber mat, and 20 min of cryogenic treatment, were shown to produce the maximum mechanical strength (65.47 MPa of tensile, 97.34 MPa of flexural, and 52.82 J/m2 of impact). This is because residual strains are produced at low temperatures (cryogenic treatment) due to unstable matrices and fiber contraction. This interfacial stress helps maintain a relationship between the reinforcement and resin and improves adhesion, leading to improved results. Based on statistical evaluation, the ratio of correlation (R2), mean square deviation, and average error function of the experimental and validation data sets of the experimental models were analyzed. The ANN displays 0.9864 values for impact, 0.9842 for flexural, and 0.9764 for tensile. ANN and RSM models were used to forecast the mechanical efficiency of the suggested nanocomposites with up to 95% reliability.

Bidirectional fabric evolution in Hamelin Pool microbialites, Shark Bay, Western Australia

AbstractHamelin Pool, Shark Bay, Western Australia hosts the world's largest and most extensive assemblages of living marine microbialites, comparable in size and shape to ancient structures found throughout the fossil record. Documented here are the internal fabrics of modern microbialites collected throughout Hamelin Pool. Mesoscale and microscale observations of microbialite polished slabs and thin section scans, optical microscopy and scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy formed the basis for a fabric classification system that combines accretionary mat type with microfabric. Accretionary mat types included pustular, smooth, colloform, as well as ‘transitional’ mats that are a cross between pustular and smooth mats. Mapping of fabrics in 45 microbialite heads indicated bidirectional evolution. An upward progression of fabrics corresponded to changes in mat type as the head grew upward into shallower water. A downward evolution of microfabrics occurred as surface mats transitioned into the subsurface of the microbialite structure. Downward microfabric evolution occurred as a result of early taphonomic processes, and involved a progression from the original depositional architecture to subsequent stages of “Micritic Thickening”, and finally, “Cement Infilling”. The observed bidirectional evolution of microbialite microfabrics within Hamelin Pool offers a conceptual framework for the study of modern microbialites, not simply as the sole product of accretionary mat types but rather as the combined result of the activity of surface mats and their taphonomic evolution. Early taphonomic processes induce further lithification of the microbialites which may enhance preservation potential in the geological record.

A study on the evaluation of impact sound reduction performance of floor mats for reducing floor impact sound in apartment buildings

This is a study on the performance evaluation of floor mats used to reduce floor impact sound in apartment houses in South of Korea. A total of 8 types of floor mats and 5 or more test rooms with different floor structures were used to measure and evaluate impact sound reduction performance. The impact source is a Bang machine (heavy-weight impact sound 1), a rubber ball (drop of height 100 cmHeavy-weight impact sound 2) tapping machine (light-weight impact sound), and a rubber ball drop height of 40cm that simulates the actual impact force. As a result of the test, the impact sound reduction performance for the light-weight impact sound was evaluated as excellent. It was evaluated at the level of ambient background noise. Also, the reduction performance of the bang machine was somewhat different depending on the floor structure. In addition, there are cases where it is rather amplified in the low frequency band (63 Hz). In the case of rubber ball (drop of height 100 cm), the reduction performance was different depending on the floor structure. However, the impact sound reduction performance was evaluated to be sufficiently reduced. The impact noise reduction performance at the rubber ball drop height of 40 cm was found to be slightly higher than that at the drop height of 100 cm.

Livestock grazing may weaken N deposition effects on soil C:N:P stoichiometry in alpine grassland of the Qinghai-Tibetan Plateau

Increased nitrogen (N) deposition is expected to impact the grassland ecosystem by changing soil C:N:P stoichiometry. However, N deposition effects on soil C:N:P stoichiometry is still in debate. In addition, we still know less about how N deposition affects soil C:N:P stoichiometry in grazed grassland as most studies focus on natural grassland. Hence, it is necessary to examine N deposition effects on both ungrazed and grazed grassland and clarify the disparity. We conducted a simulated N deposition experiment in ungrazed and grazed grassland of two grassland types including alpine meadow (AM) and alpine steppe (AS) to test such effects. Results showed that N deposition effects on ungrazed and grazed grassland varied. Soil C, soil N, soil P, soil C:N, soil N:P and soil C:P were significantly affected by N deposition in ungrazed grassland while only soil N, soil P, soil C:N, soil N:P were significantly affected by N deposition in grazed grassland. Soil C and soil N:P were not sensitive to N deposition in grazed grassland. N deposition negatively affects soil P in ungrazed grassland yet positively affected soil P in grazed grassland. N deposition effects accounted for 30% in ungrazed grassland, while significantly decreased to 12% when grazing effects were considered suggesting that livestock grazing might weaken N deposition effects on soil C:N:P stoichiometry. In addition, other climate and environmental factors such as MAT, MAP, and grassland type can also mediate N deposition effects on soil C:N:P stoichiometry in both ungrazed and grazed grasslands. On the whole, our findings suggested that there existed a disparity of N deposition effects on soil C:N:P stoichiometry between ungrazed and grazed grassland, and livestock grazing may weaken N deposition effects on soil C:N:P stoichiometry in alpine grassland of the Qinghai-Tibetan Plateau.

The effect of κ-carrageenan and ursolic acid on the physicochemical properties of the electrospun nanofibrous mat for biomedical application

Wound dressing materials such as nanofiber (NF) mats have gained a lot of attention in recent years owing to their wonderful effect on accelerating the healing process and protection of wounds. In this regard, three different types of NF mats were fabricated using pure polyvinylpyrrolidone (PVP), PVP/κ-carrageenan (KG), and ursolic acid (UA) in the optimal PVP/KG ratio by electrospinning method to apply them as wound dressings. The morphology, chemical structure, degradation, porosity, mechanical properties and antioxidant activity of the produced NFs were investigated. Moreover, cell studies (e.g., cell proliferation, adhesion, and migration) and their antibacterial properties were evaluated. Adding KG and UA reduced the mean diameter size of the PVP-based NFs to ∼98 nm in the optimal sample, with defect-free morphology. The PVP/KG/UA 0.25 % exhibited the highest porosity, hydrophilicity, and degradation rate and a wound closure rate of 60 %, 2.5 times higher than that of the control group. Furthermore, this sample's proliferation and antibacterial ability were significantly higher than the other groups. These findings confirmed that the produced UA-loaded NFs have excellent properties as wound dressing.

Investigation of the performance of needle-punched nonwoven fabrics using Triumfetta cordifolia and thermoplastic fibers, compared to other commercial bast fibers used in preformed biosourced composites

In an attempt to increase biodiversity in natural plant fiber nonwovens, new sources of natural fibers must be discovered. Nonwoven fabric is a promising commercial product for upgrading the new bast fiber Triumfetta cordifolia (TCF) and giving it an opportunity to be used in composite nonwoven applications. Two types of TCF nonwoven mats blended with polylactide fibers for one and polypropylene fibers for the other at a mass ratio of 50 : 50 were manufactured using carding and needling technology. The aim of the present work is to compare the different types of TCF-based nonwovens with other nonwovens based on commercial bast fibers, namely flax and hemp, known for their use in automotive interiors. The nonwoven fabrics were characterized in terms of weight per unit area, thickness, tensile strength and flexural rigidity. In addition, morphological aspects of fiber organization, density and distribution within the nonwoven reinforcement were observed using Scanning Electron Microscopy. The results revealed great variability in terms of surface density and thickness. Increasing the surface mass of nonwovens led to an increase in mechanical performance in terms of strength and stiffness, while retaining anisotropy in terms of fiber orientation, which has a significant effect on mechanical behavior due to the preferential fiber orientation generated during carding. In addition, the type of thermoplastic polymer fiber in the nonwoven mat has an influence on the characteristics evaluated. The results obtained showed that TCFs are good candidates, given their competitive performance and availability compared with flax and hemp fibers, and that they can be used in the same composite applications. Such a non-woven mattress based on TCFs from the tropical African region, manufactured using carding and needling technology, could open up opportunities to create new value-added products that can benefit these countries from an economic and ecological point of view.

Innovative Fibrous Materials Loaded with 5-Nitro-8-hydroxyquinoline via Electrospinning/Electrospraying Demonstrate Antioxidant, Antimicrobial and Anticancer Activities.

A new type of fibrous mat based on a cellulose derivative-cellulose acetate (CA) or CA and water-soluble polymers (polyvinylpyrrolidone, PVP or poly(vinyl alcohol), PVA)-loaded with the model drug 5-nitro-8-hydroxyquinoline (5N) was fabricated via electrospinning or electrospinning in conjunction with electrospraying. Scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FTIR), water contact angle measurements and ultraviolet-visible spectroscopy (UV-Vis) were used for the complex characterization of the obtained novel material. The decoration of CA fibers with a water-soluble polymer containing the drug resulted in the facilitation of wetting and fast drug release. The 5N-containing fibrous material showed antioxidant activity. Moreover, the proposed materials' antibacterial and antifungal properties were tested against S. aureus, E. coli, P. aeruginosa and C. albicans. Well-distinguished, sterile zones with diameters above 3.5 cm were observed around all 5N-containing mats. The mats' cytotoxicity toward HeLa carcinoma cells and normal mouse BALB/c 3T3 fibroblasts was assessed. The 5N-in-CA, PVP,5N-on-(5N-in-CA) and PVA,5N-on-(5N-in-CA) fibrous mats possessed anticancer efficacies and much lower levels of toxicity against normal cells. Therefore, the as-created novel electrospun materials, which are based on polymers loaded with the drug 5N via electrospinning/electrospraying, can potentially be applied for topical wound healing and for local cancer therapy.

Environmental controls on density‐based soil organic carbon fractionations in global terrestrial ecosystems

AbstractCategorization of soil organic carbon (SOC) into different functional subpools according to their recalcitrance and protective mechanisms helps better understand ecosystems organic carbon (OC) dynamics, and various attempts have been made to explore the suitable experimental fractionation method for such purpose. However, most previous studies neglected the influences of environmental factors on the effectiveness of varying fractionation methods. Density fractionation has shown great promise in elucidating SOC immobilization mechanisms. Here, we compared three varying types of density fractionation methods (density, density + dispersion, and density + other procedures) for categorizing the SOC into three functional pools, that is, active OC (OCactive), moderately stable OC (OCm‐stable), and stable OC, (OCstable) using global data compiled for 95 sites in 31 published studies, and examined the influences of climate (mean annual temperature [MAT] and annual precipitation), vegetation type, and soil properties (soil depth, clay content, and soil type) on SOC fractions determined by the three density fractionation methods. The percentage of OCm‐stable fraction was found to be highest using the density method and lowest using the density + dispersion method, due to differential density ranges between the two methods. At a global scale, the contents of total SOC and its OC fractions decreased with temperature. Precipitation had no apparent influences on the subdivided SOC fractions using either the density + dispersion method or the method of density + other procedures, whereas soil type constrained the effect of precipitation on SOC fractions using the density method. The percentage of OCm‐stable determined by the density + dispersion method was more responsive to MAT and vegetation type than that by the other two methods. The percentage of OCstable determined by the method of density + other procedures was significantly and positively related to the clay content as the OCstable based on this method included small particles. For all the three methods of fractionation, soil type had a greater influence than the clay content on the SOC fractions, especially the OCm‐stable and the OCstable. For soil type characterized by rich metal oxides, both the density method and the method of density + other procedures could be used for SOC fractionation. For soil type rich in nutrients, the density + dispersion method would have higher sensitivity for distinguishing the OCm‐stable.