Synthetic Binders Research Articles

An Investigation of the Effects of Manufacturing Parameters On Properties of Binderless Boards Produced from Abura (Mitragyna Ciliata) Sawdust

The production of particleboards without the use of synthetic binders is desirable to prevent environmental problems. This study has produced experimental binderless boards from untreated sawdust from Abura wood using a laboratory press. Response Surface Methodology using Box-Behnken experimental design was utilized to investigate the influenceof pressing variables (pressure, pressing temperature and pressing time). Density of the bioboards produced wasbetween 523.69 and 738 kg/m3which was comparable tomedium density fibreboards. The maximum values for Internal Bonding Strength (IB), Modulus of Rupture (MOR)andModulus of Elasticity (MOE) were 0.049 MPa,1.1 MPaand100.4 MPa, respectively. It was shown that, for the range of factors studied, pressure and the pressing temperature were the more significant factors in determining the density, MOE and IB. This study showed that the sawdust can potentially be used for the manufactureof binderless boards.

Sybodies as Novel Bioreceptors toward Field-Effect Transistor-Based Detection of SARS-CoV-2 Antigens.

The SARS-CoV-2 pandemic has increased the demand for low-cost, portable, and rapid biosensors, driving huge research efforts toward new nanomaterial-based approaches with high sensitivity. Many of them employ antibodies as bioreceptors, which have a costly development process that requires animal facilities. Recently, sybodies emerged as a new alternative class of synthetic binders and receptors with high antigen binding efficiency, improved chemical stability, and lower production costs via animal-free methods. Their smaller size is an important asset to consider in combination with ultrasensitive field-effect transistors (FETs) as transducers, which respond more intensely when biorecognition occurs near their surface. This work demonstrates the immobilization of sybodies against the spike protein of the virus on silicon surfaces, which are often integral parts of the semiconducting channel of FETs. Immobilized sybodies maintain the capability to capture antigens, even at low concentrations in the femtomolar range, as observed by fluorescence microscopy. Finally, the first proof of concept of sybody-modified FET sensing is provided using a nanoscopic silicon net as the sensitive area where the sybodies are immobilized. The future development of further sybodies against other biomarkers and their generalization in biosensors could be critical to decrease the cost of biodetection platforms in future pandemics.

Is Drosophila Dpp/BMP morphogen spreading required for wing patterning and growth?

Secreted signaling molecules act as morphogens to control patterning and growth in many developing tissues. Since locally produced morphogens spread to form a concentration gradient in the surrounding tissue, spreading is generally thought to be the key step in the non-autonomous actions. Here, we review recent advances in tool development to investigate morphogen function using the role of decapentaplegic (Dpp)/bone morphogenetic protein (BMP)-type ligandin the Drosophila wing disc as an example. By applying protein binder tools to distinguish between the roles of Dpp spreading and local Dpp signaling, we found that Dpp signaling in the source cells is important for wing patterning and growth but Dpp spreading from this source cells is not as strictly required as previously thought. Given recent studies showing unexpected requirements of long-range action of different morphogens, manipulating endogenous morphogen gradients by synthetic protein binder tools could shed more light on how morphogens act in developing tissues.

Electrochemical performance of aqueous electrolytes in porous carbon derived cassava peel electrode material-based for sustainable symmetrical supercapacitor

Electrolytes have been generally recognized as one of the most important components in enhancing the electrochemical performance of supercapacitors. On the other hand, aqueous electrolytes are considered prime candidates for the development of the next generation of symmetric supercapacitors due to their low-cost, environmentally friendly, high ionic conductivity, fine ionic size, and high capacitance. Herein, the symmetrical supercapacitor of the sustainable porous carbon-based electrode material was confirmed through various aqueous electrolytes consisting of neutral, basic, and acidic Na2SO4, KOH, and H2SO4. Activated carbon is obtained from high potential biomass sources of cassava peel waste. Activated carbon synthesis was performed with a comprehensive approach in order to obtain abundant pore structure, high porosity, and improved wettability through a combination of high-temperature chemical and physical activation. in addition, the electrode material is designed to resemble a solid disc without the addition of a synthetic binder. The evaluation of the disc dimensions showed high porosity in the obtained activated carbon. Furthermore, the symmetrical supercapacitor of the optimized electrode material exhibit excellent specific capacitances of 112, 150, and 183 F g-1 at 1 mV s-1 in the electrolytes Na2SO4, KOH, and H2SO4, respectively. In addition, the highest rate capability of 70% was confirmed in the H2SO4 acid electrolyte. Moreover, their coulombic efficiency can be maintained around 89% with low equivalent series resistance 0.21-0.42 ?. Therefore, the activated carbon-based supercapacitor symmetric cell device from cassava peel shows high performance for developing high-performance supercapacitor applications with guaranteed stability in aqueous electrolytes.

Advances in the Rheology of Synthetic Binder for Sustainable Road Pavements: An Improved Protocol for DSR Testing

Bituminous binders are thermal-dependent visco-elastic materials commonly used in pavement engineering. However, synthetic binders represent quite a new family of products that can be used in the substitution of conventional binders with various purposes. Among them, clear synthetic resins recently experienced a quick diffusion since they can be employed in the production of sustainable road pavements (which address aesthetic concerns, thermal aspects, etc.). Since specific studies addressing the rheological modeling of clear synthetic binders cannot be found in the literature, the purpose of this research is setting up an advanced rheological protocol to characterize such materials, bridging the existing knowledge gap. An extensive laboratory investigation with the dynamic shear rheometer was carried out in oscillatory mode (amplitude and frequency sweeps) to analyze the stress–strain state of such binders. An innovative test at a constant strain rate was used to construct non-linear master curves, overcoming various criticisms about the stress state of the binder when subjected to time-dependent deformations. Results indicated that, using non-linear data, horizontal and vertical shift factors (functions of temperature and strain rate) can be modeled through power law equations to obtain the master curves. This method was considered suitable for depicting the rheological response of the binders displaying such complex behaviors.

Investigating Asphalt Self-Healing with Colorless Binder and Pigmented Rejuvenator

Despite asphalt self-healing with encapsulated rejuvenators having been intensively researched over the last decade, there is still uncertainty about the performance advantages granted by this technology. As a way of adding to the existing set of research methodologies, this study aimed to test the feasibility of a visual method to investigate the working mechanism of encapsulated rejuvenators in the bituminous mixture. For this purpose, clear bituminous mixtures were produced using a colorless synthetic binder and a pigment was added to the rejuvenator incorporated in the calcium alginate capsules. The internal structure of the bituminous mixtures containing these capsules was inspected both on loaded and unloaded specimens. The colored rejuvenator was also directly added to cracked specimens and its distribution was studied, along with the interaction between the rejuvenator and the synthetic binder. The results show that the rejuvenator could modify the binder to a limited extent, and the bituminous mixtures containing capsules showed evidence of rejuvenator release. It is demonstrated that the aggregate gradation of mixtures has a significant effect on capsule damage and rejuvenator release. However, the pigment can be filtrated from the rejuvenator by the capsule polymer structure and the asphalt. Even though the methodology presented some constraints, it has been proven to be capable of achieving the initial goal, while also acting as an important first step in the visual study of rejuvenator release in asphalt.

Isoform- and ligand-specific modulation of the adhesion GPCR ADGRL3/Latrophilin3 by a synthetic binder

Adhesion G protein-coupled receptors (aGPCRs) are cell-surface proteins with large extracellular regions that bind to multiple ligands to regulate key biological functions including neurodevelopment and organogenesis. Modulating a single function of a specific aGPCR isoform while affecting no other function and no other receptor is not trivial. Here, we engineered an antibody, termed LK30, that binds to the extracellular region of the aGPCR ADGRL3, and specifically acts as an agonist for ADGRL3 but not for its isoform, ADGRL1. The LK30/ADGRL3 complex structure revealed that the LK30 binding site on ADGRL3 overlaps with the binding site for an ADGRL3 ligand – teneurin. In cellular-adhesion assays, LK30 specifically broke the trans-cellular interaction of ADGRL3 with teneurin, but not with another ADGRL3 ligand – FLRT3. Our work provides proof of concept for the modulation of isoform- and ligand-specific aGPCR functions using unique tools, and thus establishes a foundation for the development of fine-tuned aGPCR-targeted therapeutics.

Structural basis for CorA channel gating using conformation-specific synthetic antigen binders and single-particle cryo-EM.

The magnesium ion (Mg2+) is an abundant divalent cation in living cells, and plays a significant role in many biological processes, including energy metabolism, protein production, nucleotide replication and transcription, and muscle contraction. In prokaryotes CorA is the primary channel for Mg2+ uptake, and functionally complements the mitochondrial magnesium channel, Mrs2, whose dysfunction leads to cell death. Here we employ two different conformation-specific synthetic antigen binders (sABs) and single-particle cryo-EM to solve the structures of nanodisc-reconstituted T. maritima CorA in desaturating amounts of Mg2+ and in the complete absence of magnesium to resolutions of 3.1-3.4Å. We generated these sABs using a phage display library and competitive selections. We show CorA is nearly continuously variable in conformation when magnesium is even slightly depleted, but that discrete conformers can be isolated from our cryo-EM datasets due to our sAB-based approach. The resolutions in our dataset greatly improve on earlier cryo-EM studies, and these high-resolution structures represent the first ones in lipid-filled nanodiscs. These data show two major conformational changes as magnesium is depleted from regulatory cytoplasmic binding sites. One, the rearrangement of the cytoplasmic N-terminal regulatory region due to the absence of bound Mg2+, driven both by charge-based repulsion and compensating interactions. Two, concerted molecular motions driven by electrostatic interactions, leading to dilation of the pore and ostensibly channel activation. We also describe a conformational ensemble, with a population size inversely proportional to environmental [Mg2+], where both apparently inactive and active conformers present in equilibrium. Our new model shows CorA exists as metastable states in solution, with a stochastic relationship between open and closed channels, rather than a traditional deterministic mechanism. We believe our study provides a new template for understanding magnesium homeostasis in homologous systems.

A supramolecular cucurbit[8]uril-based rotaxane chemosensor for the optical tryptophan detection in human serum and urine

Sensing small biomolecules in biofluids remains challenging for many optical chemosensors based on supramolecular host-guest interactions due to adverse interplays with salts, proteins, and other biofluid components. Instead of following the established strategy of developing alternative synthetic binders with improved affinities and selectivity, we report a molecular engineering approach that addresses this biofluid challenge. Here we introduce a cucurbit[8]uril-based rotaxane chemosensor feasible for sensing the health-relevant biomarker tryptophan at physiologically relevant concentrations, even in protein- and lipid-containing human blood serum and urine. Moreover, this chemosensor enables emission-based high-throughput screening in a microwell plate format and can be used for label-free enzymatic reaction monitoring and chirality sensing. Printed sensor chips with surface-immobilized rotaxane-microarrays are used for fluorescence microscopy imaging of tryptophan. Our system overcomes the limitations of current supramolecular host-guest chemosensors and will foster future applications of supramolecular sensors for molecular diagnostics.

Isolation and Characterization of NpCI, a New Metallocarboxypeptidase Inhibitor from the Marine Snail Nerita peloronta with Anti-Plasmodium falciparum Activity

Metallocarboxypeptidases are zinc-dependent peptide-hydrolysing enzymes involved in several important physiological and pathological processes. They have been a target of growing interest in the search for natural or synthetic compound binders with biomedical and drug discovery purposes, i.e., with potential as antimicrobials or antiparasitics. Given that marine resources are an extraordinary source of bioactive molecules, we screened marine invertebrates for new inhibitory compounds with such capabilities. In this work, we report the isolation and molecular and functional characterization of NpCI, a novel strong metallocarboxypeptidase inhibitor from the marine snail Nerita peloronta. NpCI was purified until homogeneity using a combination of affinity chromatography and RP-HPLC. It appeared as a 5921.557 Da protein with 53 residues and six disulphide-linked cysteines, displaying a high sequence similarity with NvCI, a carboxypeptidase inhibitor isolated from Nerita versicolor, a mollusc of the same genus. The purified inhibitor was determined to be a slow- and tight-binding inhibitor of bovine CPA (Ki = 1.1·× 10-8 mol/L) and porcine CPB (Ki = 8.15·× 10-8 mol/L) and was not able to inhibit proteases from other mechanistic classes. Importantly, this inhibitor showed antiplasmodial activity against Plasmodium falciparum in an in vitro culture (IC50 = 5.5 μmol/L), reducing parasitaemia mainly by inhibiting the later stages of the parasite's intraerythrocytic cycle whilst having no cytotoxic effects on human fibroblasts. Interestingly, initial attempts with other related proteinaceous carboxypeptidase inhibitors also displayed similar antiplasmodial effects. Coincidentally, in recent years, a metallocarboxypeptidase named PfNna1, which is expressed in the schizont phase during the late intraerythrocytic stage of the parasite's life cycle, has been described. Given that NpCI showed a specific parasiticidal effect on P. falciparum, eliciting pyknotic/dead parasites, our results suggest that this and related inhibitors could be promising starting agents or lead compounds for antimalarial drug discovery strategies.

Comparison of coupled chemical pretreatment and mechanical refining of spruce sawdust: fiber network properties and initial production of lignin-bonded biocomposites

AbstractAround 50% of sawn wood remains as a by-product during the processing into timber. A large part of these by-products consists of sawdust, which still contains a lot of intact fibers and would have great potential to be used for biocomposite materials. This study investigates the influence of different pretreatments on spruce sawdust in a two-step process, where chemical pretreatments like liquid hot water (LHW), organosolv (OS), and alkali (NaOH) are coupled with a mechanical pretreatment (refining). The idea is to customize a suitable fibrous material for creating a biocomposite with a natural binder as lignin instead of synthetic binders. The first part of the study focused on comparing the different chemical pretreatments and the influence of the refining time. Each chemical pretreatment resulted in a different partially solubilized lignocellulosic matrix profile, making the matrix’s fibers less or more accessible. In the second step, the material was treated in a refiner to fibrillate the embedded fibers, enhancing the flexibility and bonding properties. Paper sheets were produced to evaluate the mechanical properties of the obtained fibrous materials. Based on the results, the most promising material was selected for further investigation. The second part of the study focused on the initial testing of the produced fibrous materials as composites. First, the fibers produced in the first part were impregnated with lignin, forming composite bars through hot-compression molding. Finally, the tensile strength of the composites was determined. Especially with higher pretreatment temperatures and longer refining times, several promising combinations could be found for the two-step process.

Mechanical and physical properties of synthetic sustainable geopolymer binders manufactured using rockwool, granulated slag, and silica fume

The substantial target of this work is to manufacture sustainable geopolymers by recycling low cost industrial wastes (granulated slag, GS; rockwool, RW; and silica fume, SF). To reveal the mineral and chemical compositions of these industrial solid wastes, they were investigated using X-ray diffraction (XRD), Fourier transform Infrared spectroscopy (FTIR), and X-ray fluorescence (XRF). The granulated slag, rockwool and silica fume were blended with the convenient quantity of alkaline reactor to formulate a hydrated pattern of geopolymers. The phase configuration, physico-mechanical effects [compressive strength (CS), porosity and bulk density] and the microstructural form of the geopolymers were studied via the X-ray diffraction, hydraulic mechanical testing device, helium pycnometer, and Field emission Scanning electron microscope (FE-SEM), respectively. The results declared that the partial substitution of RW by various ratios of SF in presence of GS affect successfully on the physico-mechanical properties of hardened geopolymers. Implication of 2 % SF boosts the physico-mechanical features of the 50GS-48RW hardened geopolymers at all curing ages especially at the age of 28 days. Therefore, the geopolymer 50GS-48RW-2SF displayed the best physico-mechanical characteristics especially the CS at 28-days (39.12 MPa) owing to the formation of diverse hydration products like CSHS, CAHS and NASHs. These results were confirmed via FE-SEM/EDX images that exhibited compact and dense microstructure rod-like crystals of CSHs and three dimensional framework structures of NASHs.

Synthetic DNA binders for fluorescent sensing of thymine glycol-containing DNA duplexes and inhibition of endonuclease activity.

Dimethyllumazine (DML)-thiazole orange (TO) conjugates were developed for fluorescence sensing of thymine glycol (Tg)-containing DNAs based on the selective recognition of the A nucleobase opposite the Tg residue. Additionally, this conjugate has demonstrated an inhibitory activity towards endonuclease III, a DNA repair enzyme, through its competitive binding to Tg-containing DNAs.

Controllable mitochondrial aggregation and fusion by a programmable DNA binder.

DNA nanodevices have been feasibly applied for various chemo-biological applications, but their functions as precise regulators of intracellular organelles are still limited. Here, we report a synthetic DNA binder that can artificially induce mitochondrial aggregation and fusion in living cells. The rationally designed DNA binder consists of a long DNA chain, which is grafted with multiple mitochondria-targeting modules. Our results indicated that the DNA binder-induced in situ self-assembly of mitochondria can be used to successfully repair ROS-stressed neuron cells. Meanwhile, this DNA binder design is highly programmable. Customized molecular switches can be easily implanted to further achieve stimuli-triggered mitochondrial aggregation and fusion inside living cells. We believe this new type of DNA regulator system will become a powerful chemo-biological tool for subcellular manipulation and precision therapy.

Preparation of spent coffee grounds-rubber composites using natural rubber latex as binder

The aim of this work was to explore the use of natural rubber latex (NRL) as a natural binder (according to the BCG concept) to replace commercial synthetic binders such as polyurethane resin. A composite sheet of spent coffee ground (SCG) and natural rubber (NR) was prepared by mixing of SCG in NRL compounds having concentrations of 30% and 60% dry rubber content (DRC). The amount of SCG in the composites was varied from 33 to 167 part per hundred rubber (phr). The mixture was cast in a mold to form a thin sheet then left drying at room temperature for 24 h. TGA thermogram shows 3 decomposition stages composed of moisture (including volatile matters), polysaccharide and lipid at 44%, 42% and 13% weight, respectively. Hardness (Shore A) increases gradually with increasing the amount of SCG, while tensile strength and elongation at break tend to decrease. Tensile strength decreases from 2.6 MPa to 1.2 MPa for the composites containing 33 phr and 133 phr of SCG, respectively. Alkaline surface treatment of SCG could improve the adhesion between SCG and NR as evidenced by the increase in tensile strength, elongation at break and compression set properties.

Laboratory design and evaluation of a functional color micro-surfacing with synthetic resin-based binder

ABSTRACT In this study light color asphalt with different resins, extract oil, and modifier usage was subjected to mechanical stirring and penetration, softening point, and ductility tests. The colloid mill prepared light color emulsified asphalt, and the emulsifying effect of different emulsifier usage on light color asphalt, waterborne epoxy resin (WER) usage and fiber-reinforced material influence color micro-surfacing modification were studied. The results showed that the light color asphalt prepared by Resin b has better low temperature performance and the optimum dose of SBS modifier content is 5% ∼ 6%. The influence degree on the mixing time of micro-surfacing is in the following order: cement > light color emulsified asphalt > water > mineral powder. The optimal emulsified asphalt consumption is 10.5%, and the corresponding pre-wetting water consumption is 6.6% through the one-hour wet track abrasion test (WTAT) and loaded wheel test (LWT). The results showed that WER could significantly enhance the wear resistance, water damage resistance, and durability of color micro-surfacing mixture but has adverse effects on the low-temperature performance of the mixture. Polypropylene fiber has better anti-wear performance, while basalt fiber has better anti-rutting performance.

A DARPin-based molecular toolset to probe gephyrin and inhibitory synapse biology.

Neuroscience currently requires the use of antibodies to study synaptic proteins, where antibody binding is used as a correlate to define the presence, plasticity, and regulation of synapses. Gephyrin is an inhibitory synaptic scaffolding protein used to mark GABAergic and glycinergic postsynaptic sites. Despite the importance of gephyrin in modulating inhibitory transmission, its study is currently limited by the tractability of available reagents. Designed Ankyrin Repeat Proteins (DARPins) are a class of synthetic protein binder derived from diverse libraries by in vitro selection and tested by high-throughput screening to produce specific binders. In order to generate a functionally diverse toolset for studying inhibitory synapses, we screened a DARPin library against gephyrin mutants representing both phosphorylated and dephosphorylated states. We validated the robust use of anti-gephyrin DARPin clones for morphological identification of gephyrin clusters in rat neuron culture and mouse brain tissue, discovering previously overlooked clusters. This DARPin-based toolset includes clones with heterogenous gephyrin binding modes that allowed for identification of the most extensive gephyrin interactome to date and defined novel classes of putative interactors, creating a framework for understanding gephyrin's nonsynaptic functions. This study demonstrates anti-gephyrin DARPins as a versatile platform for studying inhibitory synapses in an unprecedented manner.

TESTS OF SELECTED PROPERTIES OF CONSTRUCTION MORTARS MODIFIED WITH WASTE GYPSUM BINDER OBTAINED IN THE FLUE GAS DESULPHURIZATION PROCESS

The article presents the results of tests of selected properties of plastering mortars that are based on natural gypsum binder, as well as on synthetic gypsum binder from the flue gas desulphurization process. The mortars were analyzed with regards to their durability. For the purpose of the publication, the recipe (quantitative) compositions of the plastering mortars, which differed in terms of the type of used setting retarder (PlastRetard PE and tartaric acid A200), were designed. The mortar recipes were determined experimentally, assuming that the beginning of the setting time was 120 min (the average beginning of the setting time for currently available building mortars), and that the content of the binder was 70%. The assumed research program included tests of flexural and compressive strength, surface hardness, and the adhesion to the substrate. The results of the research confirmed the possibility of modifying the recipe compositions of gypsum plastering mortars.

Analysis and Research on the Use of Bulk Recycled Materials for Sound Insulation Applications

The application of recycled materials from the automotive industry in the field of the construction industry is a suitable alternative application for these materials and the use of their acoustic and thermal insulation properties. The output of recycling is granular, or chopped materials that can be used as a substitute for conventional materials. One of the important features of building materials is their acoustic properties. The measurement and evaluation of acoustic properties is carried out using an impedance tube as equipment. Measuring compact materials is quite simple and requires the preparation of a sample. Measuring the acoustic properties of granular bulk materials is more complicated and requires the development and production of a special test cartridge. Recycled bulk materials from the automotive industry such as rubber granules and chopped textiles can be applied as fillings for dividing structures. The aim of this paper was to assess the acoustic properties of different fractions of recycled rubber granules and textile chopped material and to compare acoustic properties with compact rubber and textile panels. To evaluate and compare sound absorption coefficient (α) and sound transmission loss (R) parameters, we used basic statistical methods and hypothesis testing methods. The production of compact panels is quite expensive since it is necessary to use special synthetic binders in production, and the content of these substances can also have negative effects on the environment. Based on the results of measuring the acoustic properties of bulk recycled materials and comparing them with compact materials, we can conclude that bulk recycled rubber and textile materials have very good values for their acoustic properties, which enables them to be used in several areas of industry.

Canola Meal as Raw Material for the Development of Bio-Adhesive for Medium Density Fiberboards (MDFs) and Particleboards Production.

In the context of natural resource scarcity, environmental challenges and human health concerns, the development of alternative solutions becomes crucial to sustainable development. Sustainable and renewable protein-containing materials such as soy or canola have proved to have wood bonding properties comparable to those of synthetic binders. In addition, the availability of canola meal offers a great possibility for the development of bio-adhesives for the wood-based panel industry. Furthermore, direct utilization of canola meal helps to avoid expensive and low-yield protein isolation processes. Using three different solvent solutions (water and 1 mol and 2 mol sodium hydroxide), canola-based bio-adhesives were prepared and used for the production of medium-density fiberboards (with 10 mm thickness and 800 kg/m3 target density) and three-layer particleboards (with 15 mm thickness and 640 kg/m3 target density). The produced boards were tested for their mechanical properties and dimensional stability according to European norms. With the MDFs’ bending strength values above 40 N/mm2 and internal bonding strength greater than 0.5 N/mm2, the results show that there is indeed a possibility to achieve good mechanical properties using canola meal as a binder. The use of NaOH solutions as denaturants, as well as the addition of colasol, helped improve the bonding properties of the boards by 35.49% and 64.52% for 1 mol and 2 mol NaOH solutions, respectively. The obtained results show that the developed canola-based bio-adhesive can compete with conventional ones. However, despite the good mechanical properties of the produced boards, their poor dimensional stability due to the low water resistance of natural proteins suggests further improvement for industrial application.