Synthetic Materials Research Articles

Knoevenagel reaction promoted by functional ionic liquids with primary and tertiary amines

ABSTRACT Functional ionic liquids have been widely used in the fields of synthetic chemistry, analytical chemistry, electrochemistry and material chemistry owing to their excellent properties such as easy structure modification and adjustable properties. In this work, a series of basic functionalized ionic liquids were prepared from 1, 4-diazabicyclo [2.2.2] octane (DABCO) or hexamethylenetetramine (HMTA) with various halogenated hydrocarbons, then these functional ionic liquids and water were used as solvent-catalyst system in the Knoevenagel reaction of various aldehydes with ethyl cyanoacetate or malononitrile, the influence of the structure of the ionic liquid and the content of water was investigated. The results showed that the composite solvent-catalyst system mixed by the functional ionic liquid N-(3-aminopropyl)-1,4-diazabicyclo [2.2.2] octane bromide with water can effectively promote the Knoevenagel reaction and the alkalinity of amine and hydrogen bond play an important role. Aromatic aldehydes with electron-donating or electron-withdrawing groups can obtain the target product at an excellent yield (79-99%). It is worth noting that the polycyclic aromatic aldehydes with high steric hindrance, 86%-95% yields of the object products were also obtained after 15 h-25 h. Furthermore, the catalyst could be reused for 6 times without any loss in its catalytic activity. The composite solvent-catalyst system mixed by the Functional ionic liquid N-(3-aminopropyl)-1,4-diazabicyclo[2.2.2]octane bromide with water can effectively promote the Knoevenagel reaction, even for the electron-rich aromatic aldehydes with poor reactivity, high yields of the target products and fast reaction rate were also obtained at room temperature.

Wildlife fencing at German highways and federal roads – requirements and management implications

In Germany, the high risk of wildlife–vehicle collisions (WVC) is further increasing due to increasing traffic volumes and road densities as well as the growing population densities of common ungulate species. As a result, threats to human health and property as well as wildlife mortality of widely spread and rare species increase. Currently, three basic types of wildlife fences are used in Germany: type A, a conventional galvanized‐high tensile deer fence (made of knot braid); type B, a chain wire (mesh wire) fence; type C, a rigid welded wire mesh fence panels. Since fencing needs to restrict access of many different species with different behaviours (e.g. jumping, climbing, digging), fencing needs to be multifaceted to be effectively. Furthermore, the occurrence of wildlife species with habits such as jumping, climbing or digging determines the optimal (functional) fence design per location. We surveyed road managers in combination with a personal assessment of road sections in Germany and derived the following recommendations for optimal fencing to reduce WVC: 1) To deter digging, use plates made of recycled synthetic materials or a concrete foundation, instead of barbed wire. 2) Fencing should be made of chain wire (mesh wire, type B) fence or rigid welded wire mesh fence panels (type C) instead of knot braid mesh (type A). 3) To restrict climbing, use angled chain wire fence or rigid welded wire mesh fence panels at the top of the fences. 4) Maintain fences so that they are kept free from ingrown vegetation/woods. Maintenance conditions should be considered while planning and building the fence, especially to ensure sufficient space on both sides for accessibility. 5) Fencing should be established preferably near the roadside and moved away from property lines. In conclusion, wildlife fencing could be a very effective mitigation measure to prevent WVC with common as well as protected species, when proper designed and recommendations of the survey will be consequently considered. Currently many wildlife fences lack functionality due to an inappropriate design and maintenance issues in Germany.

A Concise Overview of Ultrasound-Assisted Techniques for the Production of 2D Materials

The production of low-dimensional materials is the key topic of nanoscience. The development of new routes to downsize organic and inorganic materials has focused the attention of a great part of the scientific community that is still debating on the best route to pursue. Among nanostructures, 2D species have been investigated since the discovery of graphene. Nonetheless, the production of 2D materials is very complex, and the discussion on which is the most profitable way is still open. Ultrasound-assisted techniques represent one of the best routes for the production of 2D materials with minimum consumption of energy and best performances. Accordingly, we present a concise and exhaustive discussion about the use of ultrasound-assisted techniques for the production of both organic and inorganic 2D materials, also providing a theoretical overview of the mechanism behind the use of ultrasounds in synthetic material science.

Thickness and width of the menisci of adult knee joint: a descriptive cross-sectional observational study in cadavers.

The goal was to determine the thickness and width of the knee joint meniscus at their different regions. The objective was to compare the dimensions at these regions and over the right- and left-sided specimens. The present study included 50 adult cadaveric knee joints, and 100 menisci (50 medial menisci and 50 lateral menisci) were studied. The meniscus was distributed into anterior, middle and posterior parts. Thickness and width at the mid-point of these three parts were determined by using the Vernier caliper. The breadth of the medial meniscus was 8.38 ± 1.64 mm, 7.68 ± 1.92 mm and 13.93 ± 2.69 mm at the anterior, middle and posterior one-third regions. Same measurements for the lateral menisci at these regions were 9.84 ± 1.78 mm, 8.82 ± 2.01 mm and 10.18 ± 2.23 mm, respectively. The thickness of the medial meniscus was 4.49 ± 0.78 mm, 4.07 ± 0.81 mm and 4.79 ± 0.93 mm at these regions. The lateral meniscus thickness was 3.82 ± 0.69 mm, 4.43 ± 0.98 mm and 4.36 ± 0.8 mm, respectively. It is believed that this data is enlightening to the arthroscopic surgeon during the meniscus transplantation either by using synthetic material or allograft as the proper sizing of the meniscus is important to prevent complications due to inaccurate sizing.

Contribution of the ELRs to the development of advanced in vitro models.

Developing in vitro models that accurately mimic the microenvironment of biological structures or processes holds substantial promise for gaining insights into specific biological functions. In the field of tissue engineering and regenerative medicine, in vitro models able to capture the precise structural, topographical, and functional complexity of living tissues, prove to be valuable tools for comprehending disease mechanisms, assessing drug responses, and serving as alternatives or complements to animal testing. The choice of the right biomaterial and fabrication technique for the development of these in vitro models plays an important role in their functionality. In this sense, elastin-like recombinamers (ELRs) have emerged as an important tool for the fabrication of in vitro models overcoming the challenges encountered in natural and synthetic materials due to their intrinsic properties, such as phase transition behavior, tunable biological properties, viscoelasticity, and easy processability. In this review article, we will delve into the use of ELRs for molecular models of intrinsically disordered proteins (IDPs), as well as for the development of in vitro 3D models for regenerative medicine. The easy processability of the ELRs and their rational design has allowed their use for the development of spheroids and organoids, or bioinks for 3D bioprinting. Thus, incorporating ELRs into the toolkit of biomaterials used for the fabrication of in vitro models, represents a transformative step forward in improving the accuracy, efficiency, and functionality of these models, and opening up a wide range of possibilities in combination with advanced biofabrication techniques that remains to be explored.

Room Temperature-Built Gas Sensors from Green Carbon Derivative: A Comparative Study between Pristine SnO2 and GO-SnO2 Nanocomposite

Room temperature-built gas sensors were fabricated from graphene oxide (GO), pristine and doped SnO2 nanostructures. The as-synthesized green carbon derivative (GO) nanomaterials were prepared from waste plastic precursor using Modified Hummer’s methodology. Pristine SnO2 and GO-SnO2 nanocomposite were synthesized employing a wet synthesis technique known as co-precipitation. The as-prepared nanoparticles were investigated for structural crystallographic and morphological features using X-ray diffractometry (XRD) and Transmission electron microscopy (TEM) analytical techniques. High-angle annular dark field (HAADF) and elemental quantifications of the nanopowders were investigated with the Energy dispersive X-ray spectroscopy (EDX). Textural features were determined with the assistance of Brunauer-Emmett-Teller (BET) analyzer. Thermogravimetric analysis (TGA) was performed to ascertain the material stability and degradability of the synthetic materials. Functional group and bond structure analysis was conducted using Fourier-transform infrared (FTIR) spectroscopy. Gas sensor devices were tested for responses towards CH4, H2, LPG, and CO2 gases at 20 ppm concentrations of each. GO-SnO2 nanocomposite sensing device showed optimal detection response towards the respective analyte gases with values of 5.00, 5.08, 4.90 and 3.41 respectively. The prepared nanocomposite showed stability and selectivity towards the target gases in an order of magnitude of H2 > CH4 > LPG > CO2. The optimal gas sensor device’s dynamic gas sensing response was ascribed to the GO doping effect which relatively increased its surface area (46.48 m2g-1) and absorption sites.

Comparison of mechanical and comfort properties of natural fiber-based spacer fabrics for shoe insole

The objective of this study is to develop an improved shoe insole that enhances heat and moisture transmission (thermo-physiological comfort) qualities, as well as its mechanical characteristics, through the utilization of weft knitting spacer fabric. Two samples were prepared. One sample was comprised of Tri-Blend knitted fabric layers, while the other sample was made using cotton knitted fabrics in both layers. These layers, in both samples, were connected by spacer yarns of monofilament nylon. Tri-blend fabric was made from Bamboo (80%), flax (15%), and polypropylene (5%). Monofilament nylon was used in spacer layer. Thermo-physiological comfort testing i.e., air permeability, moisture management and thermal resistance test were performed for all the samples. The investigation also established the correlation between the mechanical properties, such as puncture resistance and tactile comfort, of footwear materials and their interaction with the human body. The prepared samples of shoe insole were also compared with the commercially available insoles made from synthetic materials. The outcome of the study suggests that the natural fiber spacer fabric can be used as an alternative to rubber. In conclusion, the results of this study offer valuable insights for product developers seeking sustainable alternatives that can meet consumer demands for both wearability and comfort.

New Composites Derived from the Natural Fiber Polymers of Discarded Date Palm Surface and Pineapple Leaf Fibers for Thermal Insulation and Sound Absorption.

New composites made of natural fiber polymers such as wasted date palm surface fiber (DPSF) and pineapple leaf fibers (PALFs) are developed in an attempt to lower the environmental impact worldwide and, at the same time, produce eco-friendly insulation materials. Composite samples of different compositions are obtained using wood adhesive as a binder. Seven samples are prepared: two for the loose natural polymers of PALF and DPSF, two for the composites bound by single materials of PALF and DPSF using wood adhesive as a binder, and three composites of both materials and the binder with different compositions. Sound absorption coefficients (SACs) are obtained for bound and hybrid composite samples for a wide range of frequencies. Flexural moment tests are determined for these composites. A thermogravimetric analysis test (TGA) and the moisture content are obtained for the natural polymers and composites. The results show that the average range of thermal conductivity coefficient is 0.042-0.06 W/(m K), 0.052-0.075 W/(m K), and 0.054-0.07 W/(m K) for the loose fiber polymers, bound composites, and hybrid composites, respectively. The bound composites of DPSF have a very good sound absorption coefficient (>0.5) for almost all frequencies greater than 300 Hz, followed by the hybrid composite ones for frequencies greater than 1000 Hz (SAC > 0.5). The loose fiber polymers of PALF are thermally stable up to 218 °C. Most bound and hybrid composites have a good flexure modulus (6.47-64.16 MPa) and flexure stress (0.43-1.67 Mpa). The loose fiber polymers and bound and hybrid composites have a low moisture content below 4%. These characteristics of the newly developed sustainable and biodegradable fiber polymers and their composites are considered promising thermal insulation and sound absorption materials in replacing synthetic and petrochemical insulation materials in buildings and other engineering applications.

Shaping sustainable pathways: Enhancing mechanical properties of biocomposite through tannic acid treatment of flax fabrics

Biocomposites developed using natural fibers serve as a sustainable alternative to synthetic composite materials. However, narrowing the performance gap between synthetic composites and biocomposites requires serious efforts. A promising approach is the modification of natural fibers using various chemical treatments. This paper investigates the potential of tannic acid (TA) treatment as a sustainable approach to enhance mechanical performance and reduce moisture absorption of flax fabric-reinforced biocomposites. The methodology involves the treatment of flax woven fabric with tannic acid, a naturally occurring polyphenolic compound, followed by the fabrication of biocomposite using a green epoxy matrix. The variables studied during treatment are TA concentration and processing time. Characterization of untreated and treated flax fabric and its composites was done using various analytical techniques such as FTIR spectroscopy, moisture absorption and mechanical testing (tensile strength, flexural strength, and impact resistance). FTIR spectroscopy of TA-treated flax confirmed attachment of aromatic rings and carbon double bond formation, thus serving for properties enhancement. The mechanical characterization of composites showed that properties are enhanced up to an optimum limit of concentration and processing time i.e., 1 % concentration and 30 min of processing. Moisture absorption of the TA-treated composite also reduced significantly as compared to untreated composites. These findings contribute towards the advancement in sustainable biocomposites and pave the way for their utilization in various applications.

Developing Green Sorbents Derived from Natural Materials for Microextraction and Determination of Emerging Contaminants

Microextraction technologies emerged as an attractive and eco-efficient alternative in sample preparation with the advent of solid-phase microextraction (SPME).1 The sensitivity and precision of methodologies based on microextraction are improving due to the ease of preconcentration and automation capacity that they provide, respectively. Furthermore, the miniaturization and eco-efficiency have improved considerably by using less space and avoiding the use of toxic reagents and high volumes of organic solvents. From the 1990s until the present, SPME has continued to evolve, becoming commercially available for many chromatographic applications. Also in this period, stir bar sorptive extraction (SBSE) has become another commercially available alternative,2 with the extraction device offering a greater volume of sorbent phase compared to SPME. Simultaneously, other novel microextraction techniques have emerged that complement some of the drawbacks of SBSE.3 Among these microextraction techniques, rotating-disk sorptive extraction (RDSE) was proposed by our research group in 2009 and has been recently reviewed, considering all its advances and applications.4,5 The heart of all microextraction technologies is the nature of the sorbent phase. In the context of solid sorbents, they can be classified as synthetic or natural materials according to their origin (Figure 1). Typical examples of synthetic sorbents range from the most hydrophobic octadecyl (C18) to the ion exchange phases, most of them being commercially available. Sorbents of intermediate polarity (hydrophilic–lipophilic balance) and hydrophilic-like silica-based sorbents are also commercially available. In the specific case of emerging contaminants, the copolymer of divinylbenzene and N-vinylpyrrolidone (OasisTM HLB) has largely been used, considering that its hydrophilic–lipophilic balance allows various sorption interactions with emerging contaminants. Among them, hydrophobic interactions occur through -stacking and polar interactions occur via hydrogen bonding. The hydrophilic–lipophilic balance typical of OasisTM HLB has encouraged its use in RDSE as a sorbent in multiresidue analysis.6,7 Although sorbents based on these commercial polymers are being used in different microextraction techniques, some trends are currently being claimed in the design of solid sorbents by considering new synthetic materials. In this context, micro- and nanomaterials have been tested, such as carbon nanotubes, graphene and fullerenes.8 Interactions via delocalized -electrons are especially important for molecules containing aromatic rings, as in the case of emerging contaminants. Other nonconventional materials9 that are being actively studied as synthetic sorbents are porous solids such as metal organic frameworks, covalent organic frameworks and layered double hydroxides. Together with these sorbent developments, the innovation in materials of natural origin, which can be recycled, is another parallel trend in analytical chemistry and is the central idea to be addressed in the current research of our team. As mentioned previously, a current challenge in analytical chemistry is to emphasize the use of eco-efficient or green analytical processes, positioning this characteristic at the same level as the sensitivity and selectivity of the measurement. Microextraction technology is green per se, given the minimization of the consumption of organic solvents in the sample preparation stage. However, an even higher level of analytical eco-efficiency (or greenness) is achieved when the sorbent phase used is of natural origin; in this way, the use of natural materials is in line with the change of the paradigm of typical production models (take–make–dispose) towards a circular model of waste reuse.10 Sorbents of natural origin can be classified according to their chemical composition as inorganic and organic sorbents. Clay is an example of an inorganic sorbent that plays an important role in the retention/mobility behavior of chemicals in the soil. Consequently, materials based on clay have been proposed as sorbents in different microextraction devices.11 Clays can also be modified to decrease their polarity for use in the sorption of hydrophobic analytes.11,12 Natural organic sorbents, also called biopolymeric sorbents, can be classified by their origin as natural polymers of plant origin (polysaccharides, proteins, polyesters), animal origin (polysaccharides, proteins, resins) and microbial origin (polysaccharides, polyesters, polyamides, polyanhydrides).13 All these materials prepared from natural biopolymers have been studied and proposed primarily in water treatment technologies; however, they could also be considered in the field of analytical chemistry as microextraction/extraction sorbents. The main novelty of this idea is that it is only recently, and in only a few cases, that these sorbents been used in microextraction technology, with wide future perspectives being expected.10,13 These natural materials can also be modified through known reactions of functionalization (selective oxidation, esterification, crosslinking, copolymerization, etc.). Such modifications reinforce the potential of the functional group and the number of active sites of the sorption material.14 In addition, modification of the natural materials can be achieved by pyrolysis to produce biochar. During the pyrolysis process, the components are thermally decomposed at different temperatures and times, expanding their porosity. Besides to increase the degree of aromatic condensation and aromaticity, typical functionalities present on the biochar surface include hydroxyl, carboxylic, lactone, amine and amide moieties, which are the key to its sorptive properties15 and the retention of pollutants of different natures. Similarly, from these natural materials, activated carbon can be generated at a significantly lower cost than from the same commercial substrate. To prepare activated carbon from these natural materials, two basic steps are required: pyrolysis of the raw material; and activation. Pyrolysis in the temperature range of 300–900 °C produces biochar with the required porosity associated with high carbon content. The activation step then provides a material with a higher surface area, generating additional porosity, and allows adjustment of the chemical surface to produce unique characteristics.16 During recent years, our research group has been contributing to this research field by designing new natural sorbent phases to be applied in the microextraction of emerging contaminants from wastewater and river water. Some examples of natural sorbent phases implemented in our laboratory are peanut shells,17 cork,18 avocado seed19 and chitosan.20 In various instances, these materials or their derivatives have shown comparative sorption behavior with commercial sorbents such as OasisTM HLB. By using these natural sorbents, emerging contaminants have been quantified in wastewater and river water samples from the metropolitan region of Chile.

Skin simulants for wound ballistic investigation - an experimental study.

Gunshot wound analysis is an important part of medicolegal practice, in both autopsies and examinations of living persons. Well-established and studied simulants exist that exhibit both physical and biomechanical properties of soft-tissues and bones. Current research literature on ballistic wounds focuses on the biomechanical properties of skin simulants. In our extensive experimental study, we tested numerous synthetic and natural materials, regarding their macromorphological bullet impact characteristics, and compared these data with those from real bullet injuries gathered from medicolegal practice. Over thirty varieties of potential skin simulants were shot perpendicularly, and at 45°, at a distance of 10m and 0.3m, using full metal jacket (FMJ) projectiles (9 × 19mm Luger). Simulants included ballistic gelatine at various concentrations, dental silicones with several degrees of hardness, alginates, latex, chamois leather, suture trainers for medical training purposes and various material compound models. In addition to complying to the general requirements for a synthetic simulant, results obtained from dental silicones shore hardness 70 (backed with 20% by mass gelatine), were especially highly comparable to gunshot entry wounds in skin from real cases. Based on these results, particularly focusing on the macroscopically detectable criteria, we can strongly recommend dental silicone shore hardness 70 as a skin simulant for wound ballistics examinations.

Bioinspired Polymers: Bridging Nature’s Ingenuity with Synthetic Innovation

This review delves into the cutting-edge field of bioinspired polymer composites, tackling the complex task of emulating nature’s efficiency in synthetic materials. The research is dedicated to creating materials that not only mirror the strength and resilience found in natural structures, such as spider silk and bone, but also prioritize environmental sustainability. The study explores several critical aspects, including the design of lightweight composites, the development of reversible adhesion methods that draw inspiration from nature, and the creation of high-performance sensing and actuation devices. Moreover, it addresses the push toward more eco-friendly material practices, such as ice mitigation techniques and sustainable surface engineering. The exploration of effective energy storage solutions and the progress in biomaterials for biomedical use points to a multidisciplinary approach to surpass the existing barriers in material science. This paper highlights the promise held by bioinspired polymer composites to fulfill the sophisticated needs of contemporary applications, highlighting the urgent call for innovative and sustainable advancements.

Unraveling the influence of channel size and shape in 3D printed ceramic scaffolds on osteogenesis

Bone has the capacity to regenerate itself for relatively small defects; however, this regenerative capacity is diminished in critical-size bone defects. The development of synthetic materials has risen as a distinct strategy to address this challenge. Effective synthetic materials to have emerged in recent years are bioceramic implants, which are biocompatible and highly bioactive. Yet nothing suitable for the repair of large bone defects has made the transition from laboratory to clinic. The clinical success of bioceramics has been shown to depend not only on the scaffold's intrinsic material properties but also on its internal porous geometry. This study aimed to systematically explore the implications of varying channel size, shape, and curvature in tissue scaffolds on in vivo bone regeneration outcomes. 3D printed bioceramic scaffolds with varying channel sizes (0.3 mm to 1.5 mm), shapes (circular vs rectangular), and curvatures (concave vs convex) were implanted in rabbit femoral defects for 8 weeks, followed by histological evaluation. We demonstrated that circular channel sizes of around 0.9 mm diameter significantly enhanced bone formation, compared to channel with diameters of 0.3 mm and 1.5 mm. Interestingly, varying channel shapes (rectangular vs circular) had no significant effect on the volume of newly formed bone. Furthermore, the present study systematically demonstrated the beneficial effect of concave surfaces on bone tissue growth in vivo, reinforcing previous in silico and in vitro findings. This study demonstrates that optimizing architectural configurations within ceramic scaffolds is crucial in enhancing bone regeneration outcomes. Statement of significanceDespite the explosion of work on developing synthetic scaffolds to repair bone defects, the amount of new bone formed by scaffolds in vivo remains suboptimal. Recent studies have illuminated the pivotal role of scaffolds’ internal architecture in osteogenesis. However, these investigations have mostly remained confined to in silico and in vitro experiments. Among the in vivo studies conducted, there has been a lack of systematic analysis of individual architectural features. Herein, we utilized bioceramic 3D printing to conduct a systematic exploration of the effects of channel size, shape, and curvature on bone formation in vivo. Our results demonstrate the significant influence of channel size and curvature on in vivo outcomes. These findings provide invaluable insights into the design of more effective bone scaffolds.

Development of Zeolite‐Loaded Air‐Brushed Nanofibers for Oral Use and Its Characterization

AbstractZeolites are commercially available and naturally occurring minerals and synthetic materials, they are crystalline aluminosilicates with distinctive chemical and structural properties. Zeolites have a wide range of uses, including catalysis, gas separation, agronomy, animal feed additives, ecology, medicine, and cosmetics. The antibacterial activity of zeolite‐based nanofibers is fabricated and investigated in the current work utilizing a novel airbrushing method. Airbrushing is used to create zeolite‐loaded nanofibers with two groups of 5% and 10% zeolite, respectively. Scanning electron microscopy (SEM), Attenuation of Reflectance Fourier Transform Infrared Spectroscopy (ATR‐FT‐IR), contact angle measurement and an antibacterial test against Streptococcus mutans are used to characterize the fabricated zeolite‐loaded nanofibers. The SEM pictures demonstrate that the innovative strategy used in the study—air brushing—to effectively produce zeolite‐loaded nanofibers is a success. The morphology and diameter in nanometers is verified by SEM images for both groups. The ATR‐FT‐IR peaks confirm the blended compound and its chemical structure. The water contact angle measurement of the nanofibers of both groups show the hydrophobic qualities based on wettability. The findings of the zeolite nanofiber antibacterial test show a zone of inhibition (ZOI) of 19 mm compared to a positive control groups ZOI of 28 mm, indicating superior antibacterial activity against gram‐positive S. mutans. Based on the findings, it can be stated that zeolite nanofiber can be created by airbrushing and has antibacterial properties that can be utilized to stop dental caries, where S. mutans is the primary pathogenic organism.

Natural and Synthetic Drugs Approached for the Treatment of Recurrent Aphthous Stomatitis Over the Last Decade.

Recurrent aphthous stomatitis (RAS) refers to a sore and frequently recurring inflammation of the oral tissues, distinguished by the presence of small ulcers that cause significant discomfort and cannot be attributed to any underlying disease. Different treatments have been used for RAS. This review aims to provide a comprehensive overview of the treatment options over the past decade for recurrent aphthous stomatitis (RAS), encompassing both natural and synthetic treatments. It will utilize clinical efficacy studies conducted in vivo and in vitro, along with a focus on the pharmaceutical approach through advancements in drug delivery development. We conducted a thorough literature search from 2013 to 2023 in prominent databases such as PubMed, Scopus, and Cochrane, utilizing appropriate keywords of recurrent aphthous stomatitis, and treatment. A total of 53 clinical trials with 3022 patients were included, with 35 using natural materials in their research and a total of 16 articles discussing RAS treatment using synthetic materials. All the clinical trials showed that natural and synthetic medicines seemed to benefit RAS patients by reducing pain score, ulcer size, and number of ulcers and shortening the healing duration.

Fabrication of magnesium-doped biphasic calcium phosphate granules with sea urchin spine-derived porous structure

In bone regeneration, synthetic materials are required to replace autogenous bone grafts. The shape, composition, surface, and porous structure of the material are key factors in bone formation and material resorption. In this study, we describe the fabrication of Mg-doped biphasic calcium phosphate (Mg-BCP) granules comprising hydroxyapatite (HAp) and beta-tricalcium phosphate (β-TCP) by exploiting the structural and chemical characteristics of sea urchin spines. The Mg-BCP granules were cylinders with a 1.2–1.8 mm diameter and height of 1.4–1.7 mm. The β-TCP/HAp ratio and Mg content in the Mg-BCP granules were controlled within the ranges of 0.36–0.45 and 2.40–6.21 mol%, respectively. Controlling the β-TCP/HAp ratio and Mg content may contribute to controlling the material resorption rate and promoting osteogenesis and angiogenesis. The Mg-BCP granules maintained the structural characteristics of the sea urchin spines. The granules comprised radial wedges termed septa, and a meshwork termed stereom. The interseptal gaps, or micropores, decreased from the granular exterior (24–29 μm) to the interior (14–28 μm). The septa in the outermost layer provide concavities on the sides of the cylindrical granules. The stereom meshworks in the core and outer layers involved micropores in the ranges of 3–15 and 3–10 μm, respectively. These multiscale pores and surface undulations may improve cell penetration and attachment, bodily fluid permeability, and protein adsorption. The compressive strengths of the Mg-BCP granules were in the range of 45.2–46.1 MPa, which are useful as bone grafts. Due to their rounded shapes, the Mg-BCP granules filled a mold more densely than the clinically used and irregularly shaped granules. These findings demonstrated that Mg-BCP granules are promising materials for bone regeneration.

One-Stage Lateral Sinus Floor Elevation Using Different Grafts: A Systematic Review of Controlled Clinical Trials.

The purpose of this systematic review was to assess histological and imaging outcomes related to new bone formation around implants, inserted simultaneously with sinus augmentation, comparing different types of grafts. Systematic Review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta- Analysis (PRISMA), and the Cochrane Handbook for Systematic Reviews of Interventions. LILACS/BVS, Medline/PubMed, Cochrane Library and Embase databases, including gray literature and manual investigation, were searched to identify clinical trials reporting human histological and imaging data of bone formation around implants, inserted into the maxillary sinus at the same moment of the elevation and augmentation procedure, using several materials. Study selection, risk of bias (Rob 2.0 or ROBINS I), quality of evidence (GRADE), and data collection were performed by two independent reviewers. Of the 1101 potentially eligible articles, 44 were retrieved, 12 were assessed for eligibility and 5 were included in this systematic review (4 randomized and one controlled clinical trials). As a result, 130 grafted sinuses with 179 installed implants in 103 patients, aged between 24 and 79 years and followed up from 6 to 15 months, were analyzed. The heterogeneity between studies did not allow the data to be combined for meta-analyses. All graft materials proved to be viable options for the intervention. The use of BCP was related to higher bone-to-implant contact. All the assessed grafts are viable options for the intervention addressed. The use of some material is justified to maintain the sinus volume and allow bone formation in the apical site of implants under the sinus membrane. Longer chair time and the morbidity of the donor site should be considered when choosing autogenous bone. Synthetic biphasic materials can be selected for this intervention due to superior values of %BIC when compared to DBB.

Applications of Scaffolds in Tissue Engineering: Current Utilization and Future Prospective.

Current regenerative medicine tactics focus on regenerating tissue structures pathologically modified by cell transplantation in combination with supporting scaffolds and biomolecules. Natural and synthetic polymers, bioresorbable inorganic and hybrid materials, and tissue decellularized were deemed biomaterials scaffolding because of their improved structural, mechanical, and biological abilities.Various biomaterials, existing treatment methodologies and emerging technologies in the field of Three-dimensional (3D) and hydrogel processing, and the unique fabric concerns for tissue engineering. A scaffold that acts as a transient matrix for cell proliferation and extracellular matrix deposition, with subsequent expansion, is needed to restore or regenerate the tissue. Diverse technologies are combined to produce porous tissue regenerative and tailored release of bioactive substances in applications of tissue engineering. Tissue engineering scaffolds are crucial ingredients. This paper discusses an overview of the various scaffold kinds and their material features and applications. Tabulation of the manufacturing technologies for fabric engineering and equipment, encompassing the latest fundamental and standard procedures.

Selective recovery of palladium from wastewater by modified PVC waste pipe

Green, efficient, and cost effective methods of recycling palladium (Pd) from wastewater have attracted increasing attention. In the present study, polyvinyl chloride (PVC) was utilized as a backbone for N-(3-aminopropyl)-imidazole to graft onto and yield an adsorbent suited for selective Pd recovery from wastewater by chlorine coordination. Batch experiments showed that the self-synthesized adsorbent had a Pd(II) adsorption rate of >99% at pH 1.0–3.0 and >93% in 4 min. The selectivity of the adsorbent in a complex mixed system containing high concentrations of typical base metals (CCu(II):CZn(II):CPd(II) = 66:33:1) was investigated, and the adsorbent demonstrated much higher selectivity for Pd (97.59%) than for Cu (0.52%) and Zn (2.96%). The adsorbent can also be reused as the adsorption rate remained above 99% after five cycles. Furthermore, waste PVC pipes also could be used as the synthetic raw material. The adsorbent demonstrated a high adsorption rate even when synthesized from discarded PVC pipes and the adsorption rate reached over 93% in 2 h and reached 95.15% at equilibrium in 4 h. Scanning electron microscopy and energy-dispersive spectrometry, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used to analyze the adsorption mechanism, which was attributed to electrostatic interaction and intermolecular interaction. The self-synthesized adsorbent is potentially applicable to the green recovery of Pd from wastewater owing to its high adsorption rate and selectivity.

Recent advances in the design and development of bioink formulations for various biomedical applications

Creating functioning tissue constructions via bioprinting holds great promise for replacing diseased or damaged tissues, which employs precise control over the geometry and composition of the build. This is an emerging technique that offers highly reproducible and accurate computerized oversight over the constructed structures, potentially opening the door to high-throughput production. Tissue constructions are made by the bioprinting method using a solution of a biomaterial or a combination of multiple biomaterials in the hydrogel form, known as the bioink, which often encapsulates the appropriate cell types. Hydrogels' aqueous and three-dimensional networked environment has made them an attractive contender for the bio-ink formulation of 3D printing in recent times. Bio ink-based composites have however made significant progress in treating wounds, repairing muscles, bone, and tissue, and delivering drugs. The current review offers a cutting-edge update on the creation of various bio ink formulations and their uses in the biomedical industry. The various methods of fabrication—laser-based, extrusion-based, and inkjet-based bioprinting—are explained, illustrated, and contrasted. Benefits and drawbacks of every method are discussed along with the bioprinting approach's difficulties, restrictions, and potential future directions. Natural, synthetic, and hybrid materials utilized as bioinks are also examined.