Members of the solute carrier (SLC) 6 family are of great medicinal value for their crucial role in the transport of small amino acids or amino acids-like substances such as serotonin, dopamine, norepinephrine, GABA, and creatine across membranes. Their dysfunction is strongly associated with a number of human diseases, like schizophrenia, depression, and Parkinson disease. Moreover, this SLC subfamily is characterised by highly similar sequences. The aim of this work is to explore the potential pathogenic effect of missense mutations in this SLC family. Missense mutation data was retrieved via a KNIME workflow from three databases (Uniprot, LitVar, ClinVar) covering multiple protein-coding transcripts with protein residue level assignment. In total, 256 data points were collected. Correspondently, single point mutations were transferred into the canonical or isoform sequence yielding putative mutated sequences. As encoding for the machine learning models, a selection of amino acid descriptors was taken to calculate the overall sequence property for both original and mutated sequences. The pathogenicity labels were transformed into binary vectors based on the descriptions from the data sources (true: likely pathogenic or pathogenic, false: likely benign or benign). Further on, we built a number of classification models using Support Vector Machine (SVM), and Logistic Regression (LR). The hyperparameters were optimized utilizing Grid Search. We used repeated Stratified K-Fold cross-validation to estimate the model performance. As a preliminary result, an accuracy value of 0.69 was achieved from a none linear SVM model based on the parameter optimized by grid search. This study demonstrates the possibility of predicting the pathogenic output of a missense mutation using sequence information.

Predicting the pathogenicity of SLC6 missense mutations with machine learning approaches

Problem-solving, teamwork, communication, work ethic, critical thinking, and chemical literature are some of the skills not always consciously developed in an analytical and instrumental analysis laboratory. Several times we tend to focus on the operation of the UV-vis, FTIR, XRF, or Raman spectrometer, sample preparation, and data analysis due to the wide number of topics that we might have to cover in our courses. However, industrial employers not only consider the technical skills of our students but also prioritize different nontechnical skills. A project-based approach was implemented in the analytical chemistry and instrumental analysis laboratory as part of the update of our chemistry program. Students were divided into teams, and each team had to propose a 5-week plan to design or implement an analytical method applied to a topic or material of their interest. The only considerations were to use some specific techniques studied in the course, to check if the materials were available in the chemistry store, and their proposal should consider relevant literature as a starting point. Developing a proposal from scratch and within a limited time frame helped the students to grasp the importance of experimental design, time management, and specialized articles to formulate and reformulate their hypothesis. Furthermore, choosing a topic of their preference kept them motivated and enthusiastic. They learned better how to use different equipment, the advantages, and limitations of each instrument, some practical considerations, and how important were to keep a good lab book to keep track of their progress. Peer and self-assessment were used to help them improve their teamwork and work ethic skills. After 5 weeks of work, they were asked to present their work to the class and their peers play the role of the reviewers, providing feedback to the other teams so they could improve their final report. This session was very useful for all of them, as it helps them to improve their critical thinking and to provide statements based on the evidence found. The final report was submitted as a manuscript in an analytical chemistry journal, and where they took into consideration all the feedback given by their peers and the instructors. This approach was greatly appreciated by all the students as they felt they no longer follow a “chemical recipe” and considered it would be of great value once they get their first job.

Improving students' research skills in the analytical chemistry and instrumental analysis laboratories with a project-based approach

Within the realm of heterogeneous catalysts, nanocatalysts are preferred due to the elevated activity and efficient utilization of materials. The later becomes very important in case of low reservoir abundance of noble metals in the earth. Since using precious metals is indispensable due to their high reactivity under mild conditions, it is necessary to minimize their use and improve their sustainability by emphasizing recovery and reuse. However, there are major practical challenges in using nanocatalysts because of their easy agglomeration during the catalytic process and the difficulty in separation from products. A strategy to avoid their mobility and improve their separability is anchoring them on a support. While metal foams have been used extensively in electrochemical and electrocatalytic applications, their utility in catalysis is comparatively underexplored. Foams have the potential for direct application in flow processes. Ni foam has the characteristics of easy handling and manipulation, high stability, inherently contiguous macroporous structure, low cost, commercial availability, and environment friendliness. Herein, we report the synthesis of a highly reactive and incredibly robust hierarchical monolith-based catalyst. Pt/Ni@Al2O3 was created through a facile hydrothermal process, followed by encapsulation with a thin layer of ALD Al2O3.The materials possesses a highly disperse Pt sites with ultra-low loading of precious metal (in the ppb range). The catalytic performance of the material was evaluated by hydrogenation of styrene with H2 gas under mild conditions (50 °C, 3 bar H2). Encouragingly, Pt/Ni@Al2O3 presents high TON (~ 160 × 106 for Pt as the active component) for the hydrogenation of styrene. Recyclability trials show negligible loss of reactivity over ten trials as tested. Various structure-reactivity relationships, including choice of Pt precursor and protective overlayer of Al2O3 are tested and discussed, and catalytic substrate scope broadly expanded. Overall, the catalyst system appears robust, facile to handle, and promising as a means of dramatically enhancing Pt catalyst sustainability by enhancing reuse and recovery.

Highly reactive and robust monolith-supported Pt catalysts for olefin hydrogenation

Alzheimer’s disease  (AD) is a chronic neurodegenerative disease that affects millions of  people worldwide. The causes of AD are complex and not fully  understood, but is widely acknowledged as a multifactorial process.  Therefore, a useful strategy for developing anti-AD agents is to design  multiple-target directed ligands (MTDLs) that can act on different aspects  of the disease. One of these aspects is the cholinergic system, which  regulates cognitive function through acetylcholine (ACh). In AD patients,  ACh levels decline significantly, leading to dementia. Thus, inhibiting  acetylcholinesterase (AChE), an enzyme that breaks down ACh, is a key  target for anti-AD drugs. Moreover, AChE can also modulate oxidative  stress and inflammation, which are also involved in AD pathology. Hence, we proposed a multi-target therapy that combines AChE  inhibitors with antioxidants to achieve a better therapeutic effect. One of  the antioxidants we chose is nuclear factor erythroid 2-related factor 2  (Nrf2), which can activate the expression of antioxidant response elements (AREs) and protect against inflammation and oxidative stress.  Herein, we designed, synthesized, and evaluated one series of hybrids as multifunctional anti-AD agents by fusing the 1,2,4-oxadiazole core from  the Nrf2 activator that we previously reported and the benzylpiperidine  motif from AChE inhibitor donepezil

Design, synthesis, and evaluation of fused hybrids with acetylcholinesterase inhibiting and Nrf2 activating functions for Alzheimer's disease

Porous materials, such as zeolites and metal–organic frameworks (MOFs), or zeolitic-organic frameworks (ZIFs), are frequently considered for shape-selective separations, molecular storage, and catalysis applications, mainly due to their hollow structures. The amount and chemical nature of sorbate molecules that may be fitted inside their cavities depend on their internal structure, that is, on their surface areas, available volumes, and shapes of their porosities. However, while the structure can be elucidated, the access to such precise structural information is somewhat limited both experimentally and computationally. Moreover, the large number of reported structures makes computational geometry-based techniques particularly attractive to identify the most suitable structures for a desired application.
In this context, Delta Chem is both a method and a program designed to quickly analyze porous structures, relying solely on their Cartesian coordinates, and characterize the shapes of their cages using regular convex polyhedra. The program provides a systematic approach to determine the positions of the porosity centers, the atoms that contribute to the internal surfaces, volumes and surface areas. It also includes a routine to compute the irreducible volumes of the cages, i.e., minimal regions of the cavities that can be used to represent the whole porosity shape via symmetry operations. The capabilities of the program are tested on well-studied porous systems, namely, C-60 fullerene, MOF-5, HKUST-1, UiO-66, and ZIF-8.
Our approach is compared against other widely used polyhedra-based approaches for porous materials. Delta Chem is a novel and systematic way of characterizing routinely porous materials and hollow molecules. Besides potential applications to systematically simplify computational studies of shape-dependent properties, Delta Chem can be used in many studies to generate basic geometrical models.

Delta Chem: A new geometric approach of porosity for symmetric porous materials

In pace with emergency of new material and progress of material synthesis process, novel energy solar cells have cells has broader application prospect. Numerical simulation of the theoretical model of these new generation solar cell absolutely involves the unique photoelectric characteristics of materials. Single and conventional simulation method and software can't meet the requirements of analysis based on both innovative device and new materials applied to the device. Consequently, we demonstrate a feasible strategy through combining the simulation method about photovoltaic devices (FDTD, Finite Difference Time Domain) and properties of materials (vasp, Vienna Ab-initio Simulation Package) to make a comprehensive and specific research on organic hybrid heterojunction solar cells (PEDOT:PSS/Si HHSCs). Our core content is related to simulate and calculate the band structure, density of states and carrier mobility of the crystalline part PEDOT and the intermediate product PEDOT:Tos, the result indicates the crystalline- PEDOT part in PEDOT: PSS directly determines its semiconductor characteristics, and also confirms that wash-off the PSS part makes the properties of PEDOT:PSS change from semiconductor characteristics to metallicity. In addition, the results of material simulation are set as input parameters in order to simulate the complete solar cell. Moreover, the etching structure for light trapping is also optimized. Eventually, the HHSCs exhibited a VOC of 0.65V, Jsc of 35.71mA/cm2, FF of 66.88%, and yielding a PCE of 15.70%, which matched with the experimental results.

Numerical simulation and research on material properties and photoelectric performance of PEDOT:PSS/Si solar cells

Recently, the interest in removing contagious viruses from indoor air using ventilation and air filtration systems is increasing rapidly because people spend most of the day indoors. The application of antiviral air filters in air conditioning and purification systems may be an alternative to achieving back-to-normal from the current pandemic because coronavirus infections are ongoing despite the vaccination of a considerable number of people worldwide. On the other hand, the development of an effective platform to regenerate the antiviral function of air filters during use as well as safe abrogation of used filters containing infectious viruses is a challenging task, because an on-demand safe-by-design manufacture system is essential for in-place antiviral coatings, but it has been rarely investigated. With these considerations, an electrically operable dispenser was prepared for decorating continuous ultrafine Fe–Zn, Fe–Ag, or Fe–Cu particles (&lt;5 nm) onto SiO2 nanobeads (ca. 130 nm) to form nanobulges (i.e., nanoroughness for engaging coronavirus spikes) in the aerosol state for 3 min direct deposition on the air filter surfaces. The resulting nanobulges were exposed to human coronaviruses (HCoV; surrogates of SARS-CoV-2) to assess antiviral function. The results were compared with similar-sized individual Zn, Ag, and Cu particles. The nanobulges exhibited comparable antiviral activity to Zn, Ag, and Cu particles while retaining biosafety in both in vitro and in vivo models because of the significantly smaller metallic fractions. This suggests that the bimetallic bulge structures generate reactive oxygen species and Fenton-mediated hydroxyl radicals for inactivating HCoV.

Plug-in aero-manufacture of nanobulges for an in-place anticoronaviral on air filters

Polybenzoxazines are a thermosetting polymer that have superior properties to traditional phenolic resins, including near zero volume shrinkage during cure, high glass transition temperature (Tg) and elevated char yields. These enhanced properties make polybenzoxazines exciting candidates for fiber reinforced polymer composites or as the polymer precursor to carbon-carbon composites. However, the grand challenge in the use of polybenzoxazines for these applications is the difficulty in processing for commercial use. Previous work has shown that monofunctional furan-based benzoxazine may offer solutions to these processing challenges without sacrificing performance. However, the single functionality increases the sensitivity to cure from the formation of linear polymers and the inability to crosslink. The difficulty in curing of these monofunctional materials limits their ability to address the grand challenge. A monofunctional furan-based benzoxazine with gastrodigenin as the phenolic derivative was first synthesized by Yu et al. This monofunctional benzoxazine has been reported to undergo crosslinking at temperatures of above 240°C before thermal degradation (380°C). In this report, the ability for the polymer to crosslink was confirmed using thermomechanical analysis and FTIR. The influence that this crosslinking has on carbon formation during pyrolysis was assessed using thermogravimetric analysis paired with both mass spectroscopy (TGA-MS) and infrared spectroscopy (TGA-IR). The carbon structure was analyzed using scanning electron microscopy (SEM), water absorptivity testing for density and porosity, Raman spectroscopy, and X-ray diffraction (XRD). Increases in crosslinking of the polybenzoxazine structure retained char yields of up to 62 % and a carbon bulk density of 1.47 g cm-3. This work shows that the monofunctional furan-based benzoxazine with gastrodigenin as the phenolic derivative with its ability to crosslink at high temperatures is an encouraging monomer for applications in high temperature composites.

Formation of a crosslinked network in a monofunctional furan-based benzoxazine and its effect on thermal stability

The students chapters of the local Puerto Rico session have suffered from the pandemic, earthquakes, and hurricanes in the last five years. This has caused instability in the social interactions of the students. For this reason, the Student Chapter from the University of Puerto Rico at Aguadilla Campus (ACS-SC-UPRAG) worked this academic year under the motto: "Bonds of Transformation and Brotherhood”, which expresses that, like every molecule, the community can form different types of bonds. Every student longs to be a molecule to form other bonds with those close to them. The members are like elements with pairs of electrons that want to develop new molecules. Through interactive, social, and psychosocial development activities, they are able to develop fundamental skills for their emotional intelligence and professional growth. Workshops such as professional interviews, community service to help the vulnerable communities and social activities such as neon game nights were used to achieve our goals. In addition, the “tree of elements” activity gives the students an opportunity to write motivational phrases in the form of an element that is placed on a tree to strengthen the emotions of our students in times of crisis. ACS-SC-UPRAG sought to enable its members with functional elements with a professional character full of scientific and socio-cultural values for the community's good, making this the ideal project. These activities complement the vision of our student chapter to preserve the diversity and emotional and professional empowerment to contribute to the development of tomorrow's scientist.

Bonds of transformation and brotherhood as sources of change

Polymer networks are renowned for their excellent thermal and dimensional stability, mechanical strength, and chemical resistance. However, due to the irreversible nature of their network structures, such materials are not recyclable. Thermosetting systems used in polymer matrix composite (PMC) applications are often confronted with this problem. PMCs are lightweight materials which combine costly reinforcements, such as carbon or glass fibers, within a continuous thermoset phase. Conventional end-of-life processes for PMCs include mechanical grinding, pyrolysis, and landfilling. In all cases, the lack of recyclability of matrix materials results in value loss of reinforcements and increases the amount of petrol-derived plastic waste in the environment. Recyclable polymer networks have been designed by incorporating labile functionalities, such as esters, imines, or acetals, onto precursor molecules. The labile nature of these chemical groups induces degradable sites within a polymer network for eventual recycling at end-of-life. Resultant materials developed from previous studies are typically thermoplastics or elastomers which exhibit insufficient thermomechanical properties of many PMC applications. In this work, acetal linkages are introduced to the main structure of bio-derived dimethacrylate monomers to create readily recyclable thermosets from renewable feedstocks which exhibit high-performance characteristics. Acetal bonds are ubiquitous protecting groups used in organic synthesis known to readily hydrolyze under acidic conditions. By this method, recovery of natural carbon and mitigated loss of high-value materials from the current linearized economy of thermosets and PMCs can be realized. Acetal linkages were successfully formed by reacting the aldehyde on methacrylated vanillin with glycerol, a highly abundant, low-value, industrial waste product. Monomer structure was characterized by several spectroscopic techniques to confirm the reaction of aldehyde groups (90-95%) and formation of cyclic acetal units. Dynamic mechanical analysis showed that homopolymerized materials formed resins exhibited excellent storage modulus (2.9 GPa @ 35°C) and glass-transition temperature (183°C by tan delta). Finally, exposure of the polymer networks to 0.1 M HCl solution at 40°C resulted in complete hydrolysis, and degradation byproducts were analyzed for reuse.

Recyclable and renewable thermosetting polymers based on acetal linkages

The ongoing pandemic has substantial lack in preparation to fight a major pandemic. Among many ways to minimize human-to-human transmission of highly contagious diseases including vaccination and social distancing, the use of mask in social gatherings have been proven to be effective. The commercial disposable masks are commonly known to be less effective to reduce transmission of microbes. Further, it is a nuisance to wear them for many hours. Disposable masks are also a threat to the environment because of producing nano and microplastics from their million tons of plastic waste as estimated since the start of COVID-19. One of many ways to promote face masks is enhancing the functionality of the mask and making them more aesthetically appealing. The use of antimicrobial surfaces on face masks, wearable devices, and publicly used surfaces are getting attention in research community. However, their large-scale use is limited due to cost, toxicity of materials used in the coating, lack of broad-band antimicrobial effectiveness and reusability for long periods. We report a low-cost, easily fabricable, and reusable antimicrobial surface (MAC) coating that provides a broadband effectiveness against bacteria (gram-positive and gram-negative), virus, and fungi. The broadband deactivation of the MAC coating is due to in-situ generation of reactive oxygen species (ROS) including H2O2, OH., and O2. Both ROS and metallic species are known to be toxic to broadband microbes. We demonstrate that the MAC treatment on the bacteria resulted in the deformation of the cell wall and formation of the nanoscale pores in the membrane. The experimental data suggested that a decrease in six log scale of bacteria was achieved within five minutes of the MAC treatment. We will also describe the role of shape, size, and morphology of nanoparticles (Ag, Cu, Au, Pd) in the microbial deactivation.

Accelerated deactivation of broad-range microbes via in-situ generation of reactive oxygenated species for wearable devices

Certain organic compounds with heteroatomic systems form a protective film on transitional metal surfaces instantaneously through physisorption and chemisorption mechanisms, which reduces the corrosive attack in a conductive liquid. Analytical identification of potential corrosion inhibitors is extremely time consuming, resource consuming, costly, and still mostly based on trial-and-error experimentation. Therefore, it is urgent to investigate the influence of the structure of a compound on corrosion inhibition efficiency as it will provide theoretical guidance for designing effective corrosion inhibitors. In this work, a Quantitative Structure-Activity Relationship (QSAR) approach is applied to investigate the structure-corrosion inhibition relationship, to be able to better understand the corrosion mechanism and discover effective corrosion inhibitors. A preliminary QSAR model has been developed based on in-house data correlating the molecular structure and corrosion inhibition efficiency of a set of organic compounds representing multiple classes of organic compounds. Applied molecular descriptors are generated by a mathematical procedure which provides exclusive chemical and physical information about compounds such as fragment-based descriptors, electronegativity, atom types, molar refractivity, and HOMO-LUMO gap. The QSAR model developed in this study is found to be correlating well with specific physical and chemical properties of organic compounds. With further improvement, this model can play an important role in the investigation of potential corrosion inhibitors. Experimental determination of corrosion of steel in the presence of corrosion inhibitors has been carried out by electrochemical Linear Polarization Resistance testing.

Combined experimental and computational assessment of the corrosion inhibition efficiency of organic compounds by predictive QSAR modeling

Metal corrosion is a global problem in industries such as construction, petroleum, and production. One common corrosion prevention is the application of polymeric coatings, acting as a physical barrier to inhibit/delay the permeation of the corrosive media. Thus, there is an opportunity to search for efficient and high-performance coatings. Composites usually performed better than the pristine matrix (e.g., polymer). Therefore, this study aimed to create a novel polymeric composite coating by insulating the metal from the corrosive environment with an inert matrix and macro fillers to make a tortuous path. Herein, Nylon 12 (PA-12) particles were dispersed as the fillers into a poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix. PVDF-HFP has fluorine atoms which endow the polymer with superior chemical resistance as well as poor adhesion properties. In contrast, PA-12 can absorb water thereby changing its size and can improve the adhesion owing to the amide groups willing to interact with the metal surface. The corrosion resistance was evaluated by Electrochemical impedance analysis (EIS) and Potentiodynamic Polarization in a 3.5 wt% NaCl test solution with Mild Steel (MS) as a substrate. Results from electrochemical measurements indicated that small amounts of PA-12 (ranging from 0 to1 wt.%) are needed to enhance, by a synergistic effect, the overall protection performance of the PVDF-HFP composite coatings. After seven days of immersion, the PVDF-HFP/PA 12 dip-coated samples (thickness &lt; 1 mil) were able to protect MS from corrosion attack. The results were supported by Microscopy, Dielectric spectroscopy, and mechanical testing (ASTM D3359-Adhesion and ASTM D3363-Hardness). The coatings with an optimum PA-12 loading increased the resistance of the coating with time and the corrosion inhibition, reduced the corrosion rate and dielectric constant, and increased the adhesion of the film with the substrate.

Enhanced corrosion resistance of PVDF-HFP/PA-12 composite coatings

Biochar has shown to be an effective adsorbent for environmental heavy metal remediation. Modifying the surface of biochar with negatively charged functional groups improves the electrostatic adsorption of the positively charged heavy metal ions. In the present research we have used three distinct methods to introduce thiol groups on the surface of biochar samples derived from different sources of biomass. We will present the physicochemical, electronic microscope, and X-ray photoelectron surface analysis data of all the thiolated biochar samples. Our study evaluates the effect of chemical methods and experimental conditions on the extent of surface functionalization of the biochar.

Studying the effect of different thiolation methods on functionalizing biochar surface from various sources

Chemical vapor deposition (CVD) is a versatile technique for the synthesis of polymer thin films, including acrylates, methacrylates, vinyls, silicones, fluoropolymers, and conjugated polymers. Dicyanate ester polymers are thermosets that have better thermal stability, lower shrinkage, lower water adsorption, and lower dielectric constant than other thermosets such as epoxies. Due to their high strength-to-weight ratio and excellent thermal and mechanical stability, dicyanate ester thin films are of interest for use in high temperature electronic substrates and scratch resistant coatings. This work describes the first synthesis of dicyanate ester thin films using CVD. Two different monomers have been utilized, one a commercial bisphenol E resin, and the second 1,4-dicyanatobenzene, synthesized in-house. Curing studies compare the effect of the substrate on network formation and monomer to polymer conversion, and include silicon, copper, and room-temperature ionic liquid (RTIL) substrates. ATR-FTIR spectroscopy was used to determine conversion extent through the presence of triazine ring bonds and disappearance of cyanate ester bonds, while XPS also confirms the bonding environments present. SEM was used to study the morphology of the thin films. Future work includes using TGA, DSC, DMA, and AFM nanoindentation to study the thermal and mechanical properties of the thin films, where the more rigid network is expected to have improved properties over the commercial resin.

Chemical vapor deposition of dicyanate ester polymer films

Global anthropogenic pollution has caused extensive damage to the soil ecosystem. At low concentrations, metallic chemicals, such as heavy metals, cause soil contamination. Some plants possess the ability to carry out phytoremediation to decontaminate soils. Using wild plants such as Sida rhombifolia L. for this would be a feasible way to prevent the bioaccumulation of heavy metals. However, one concern is that it is a slow process, which requires time to remediate the contaminated soil. For this reason, bacteria labeled as Plant Growth Promoters (PGP) are used to help increase the storage capacity of the plant. Our research proposed using Pseudomonas fluorescens as PGP to accelerate the phytoremediation process. Furthermore, we are evaluating the possible mechanism of heavy metal transportation into the plant cells using metallothioneins. For this purpose, a group of Sida rhombifolia L. species were planted in agricultural areas located on the west coast of Puerto Rico. In the analysis of bacterial microbiology, it was possible to isolate four bacterias from the soil. According to biochemical tests, these isolated colonies are not classified as Pseudomonas fluorescens. The analysis of metallothioneins is carried out using metal affinity chromatography and electrophoresis techniques to purify the samples and confirm the presence of metallothionein in the leaf of Sida rhombifolia L. The metallothioneins have a large number of cysteines available to form heavy metal bonds. In this way they can form a low molecular weight complex outside the vacuole and high molecular weight complex inside the vacuole to improve the heavy metals stabilization in plant cells. This research looks to find an effective way to extract the heavy metals from the soil, to inhibit the entrance of heavy metals in the food web, to improve sustainable agriculture growing healthy and secure food.

Metallothioneins complex-agent and Pseudomonas fluorescens as transformants for phytoremediation in soil by Sida rhombifolia L.

The melt-reprocessing of thermosets such as polyurethanes (PUs) and epoxy network materials has been a constant technical challenge. Here we report, for the first time, melt-reprocessing of mixed PUs made of aliphatic and aromatic feedstocks. Our methodology consists of using Zn (II) catalysts combined with a slight excess of diols. The use of diols was sufficient to partially reverse the gel-point and reclaim the melt-processability as demonstrated for aliphatic, aromatic, and mixed PUs. Zinc acetate was not effective in imparting melt-processability to PU samples. Furthermore, the mixed PU samples were successfully melt-processed in an extruder on a large scale. This work holds the promise to facilitate the recycling of post-consumer mixed PUs with immense benefits for science, the economy, and the environment.

Sample approach for the reprocessing of cross-linked and mixed polyurethanes

With the increasing environmental awareness of the public, government and industry seek to replace nonrenewable energy sources with renewable ones to lower greenhouse gas emissions. At the same time, energy demand continues to increase due to the development of industry and the exponential growth of the population. These concerns have the potential to be balanced with the use of wood as a fuel source. Wood is a sustainable, renewable, and low-cost resource and unlike conventional fuel sources, the use of wood for energy applications limits CO2 emissions, thus the negative impact on the atmosphere. The thermal properties of wood in energy can be improved by torrefaction, which is thermal treatment at 200-300°C in an inert atmosphere. Thermochemical conversion processes are efficient methods to produce biofuels from biomass; of these methods, torrefaction has the lowest global warming potential. Torrefied biomass is known to have higher calorific values, higher bulk and energy densities, lower biological degradation, and higher hydrophobicity. Potassium (K) is a mineral naturally present in wood and responsible for the plant’s growth. Past studies have shown K to have catalytic effects on the thermal degradation of wood powder. Since it has a major role in the degradation of lignocellulosic biomass, it is of interest to see the effect of K impregnation on the torrefaction of wood blocks instead of powder. Consequently, 14 x 6 x 2 cm3 blocks of beech were impregnated with demineralized water, 0.004 M, 0.008 M, and 0.012 M of K2CO3 solutions and torrefied at four different durations:  5 min, 15 min, 30 min, and 60 min at 275 °C. Pre-torrefaction, atomic emission spectroscopy (ICP-AES) was used to check the diffusion of K throughout the wood block's thickness and found that the surface has more K than the heart of the wood. This finding spurred interest in the examination of the effect of K and the thermal treatment throughout the wood’s thickness. Post-torrefaction, samples from the surface and core of the wood were pyrolyzed using thermogravimetric analysis (TGA) to obtain TG and DTG profiles. Likewise, X-Ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the effect of K and heat treatment on crystallinity and the char’s porosity.

Effect of potassium impregnation and torrefaction on the thermal degradation of wood blocks

The development of single-molecule techniques provides opportunities to investigate the properties and heterogeneities of individual molecules, which are almost impossible to be obtained in ensemble measurements. Recently, single-molecule fluorescence microscopy is being applied more and more to study chemical reactions in organic solvents. However, little has been done to optimize the surface preparation procedures for single-molecule fluorescence imaging in organic solvents. In this work, we developed a method to prepare the surface for single-molecule fluorescence imaging in organic solvents with a well-controlled surface density of chemically immobilized dye molecules and a low density of non-specifically adsorbed impurities. We also compared the surfaces prepared by two different procedures and studied the impacts of the polarities of the solvent and the surface functionality on the quality of prepared surface.

Surface preparation for single-molecule fluorescence imaging in organic solvents

Since 2010, our lab has disclosed several successful methodologies for the asymmetric halofunctionalization of olefins, including chlorolactonization of alkene amides and alkene carbamates, chlorocyclization of alkene amides, chlorocyclization of alkene carbamates, chloroetherification of alkene amides, chloroamidation of alkene amides and dichlorination of alkene amides. Despite advancements, mechanistic understanding of these reactions remains largely underdeveloped. the aforementioned halogenation chemistry can be achieved with DCDMH as the chlorenium source. In this study, we explored the effect of the halenium source on reaction rate, to gain a better mechanistic understanding of the interaction between the chlorenium source with other components of the reaction. Match-mismatch behaviors were interrogated as well, using chiral chlorohydantoins. Furthermore, kinetic analysis with different aryl substituted chlorohydantoin showed linear relationship ΔΔG‡ [=RT ln(kAr/kPh)] and HalA, which suggests chlorine transfer in an early transition state. Nonetheless, intermolecular halofunctionalization reactions, seem to behave differently, as evident of radically altered kinetic parameters.

Mechanistic studies of asymmetric chloroetherification reactions

As we will proceed to move away from fossil fuels, an environmentally friendly, and industrially relevant fabrication of sustainable electronic devices is as topical than ever. Spray deposition is a fast and easy-to-implement technique, and already highly used in the industry to deposit thin, homogeneous films on a large scale. Functional nanocomposites are of high interest, as they combine favorable properties of different materials in a hybrid material. Here, we explore spray deposition to fabricate two types of thin, and transparent nanocomposite electrodes consisting of wood-based, lightweight, and flexible cellulose nanofibrils (CNFs) as sustainable matrix material and highly conductive silver nanowires (AgNWs). Type I is a layered structure of an AgNW network sprayed on top of a thin CNF layer, while type II consists of a mixed layer of CNF and AgNW. We correlate the structural, morphological and electrical properties of both types using UV-Vis, SEM, AFM, grazing incidence small-angle X-ray scattering (GISAXS), and four-point conductivity measurements. Our results demonstrate that the mixed type II has a lower roughness, allows for earlier onset of conductivity and shows a lower sheet resistance than type I. Hence, the addition of CNFs to the AgNWs-solution upon spraying has beneficial templating effects on the electronic properties of the resulting AgNW network.

Fast fabrication of hybrid nanocellulose fibril-silver nanowire transparent electrodes via spray deposition

Corrosion is a global problem that results in substantial economic loss and is life-threatening as well. Currently, the utilization of self-healing coatings involving smart carriers encapsulated with the appropriate self-healing agents is a topic of great interest. Following this strategy, our work reports the synergistic corrosion inhibition performance of Polyolefin-based smart coatings containing modified hybrid-based particles. The hybrid particles (ZnO@β-CD) comprising zinc oxide (ZnO) and β-Cyclodextrin (β-CD) were synthesized and modified with 2-mercaptobenzothiazole (2-MBT). The synthesized unmodified and modified hybrid particles were characterized by numerous techniques. TGA analysis confirmed that 2MBT is effectively loaded into ZnO@β-CD with almost 43% loading. UV-vis spectroscopic analysis results suggest that the self-release behavior of 2MBT is more pronounced in the acidic medium compared to the basic and neutral medium due to the dissociation of ZnO in the acidic medium. In the next stage, the synthesized unmodified (ZnO@β-CD) and modified (ZnO@β-CD-2MBT) hybrid particles were uniformly reinforced into a polyolefin matrix, followed by its application on steel substrate via dip-coating technique to formulate smart composite coatings. The Electrochemical impedance spectroscopy (EIS) results conducted on the developed smart composite coatings demonstrate that polyolefin coatings reinforced with modified hybrid particles (ZnO@β-CD-2MBT) display improved corrosion inhibition performance (98 GΩ.cm2 ) when compared to the composite coatings (87 GΩ.cm2) containing unmodified particles (ZnO@β-CD) in 0.56 M NaCl solution after 20 days of immersion. This decent improvement in corrosion resistance behavior is attributed to the synergistic corrosion inhibition effect experienced due to the combined corrosion inhibition effect of ZnO and 2MBT.

Corrosion inhibition performance of polyolefin smart self-healing coatings modified with ZnO@β-Cyclodextrin hybrid particles

Lignin is a natural polymer and an agricultural byproduct of biorefinery industries. Lignin is the second largest renewable material on earth after cellulose. There are 50-70 million tons of lignin produced globally every year. However, lignin is underutilized and mostly burnt to generate electricity and heat. Our research valorizes this low-cost biobased feedstock to produce value-added materials. We use intrinsic chemistry and three-dimensional molecular characteristics of lignin to create both covalent and non-covalent dynamic structures to produce the materials having excellent thermo-responsive properties. We utilize molecular dynamics to manipulate thermally adaptive mechanical strength of the materials for a wide range of applications. In this talk, I will discuss the uses of advanced characterization techniques, including in-situ rheology, neutron and X-ray scattering to discover the fundamentals of these dynamic structures.

Transformation of an agricultural byproduct to thermally adaptive materials

As per the estimates of American Cancer Society, 1,918,030 new cancer cases are projected to occur in USA alone in 2022. Hence, the overall increase in cancer cases throughout the globe is alarming that warrants effective therapeutic strategy. Although, platinum based drugs like cisplatin, carboplatin, oxaliplatin, are used for treatment of cancer, they have potential side effects. Hence, the aim of the study was to develop a green route for synthesizing bioactive principles functionalized magnetic nanomaterial with promising anticancer activity. Curcumin functionalized citric acid capped iron oxide nanoparticles (IONPs) were synthesized that inhibited Agrobacterium tumefaciens induced tumors. Further a potent bioactive saponin, diosgenin from Dioscorea bulbifera was functionalized onto magnetic iron oxide nanoparticles (IONPs) core via citric acid linker molecule. FTIR analysis of IONPs-D exhibited signature peaks of diosgenin at 2914, 1166 and 1444 cm-1, confirming the efficient functionalization of diosgenin. IONPs-D exhibited high (above 50 %) antiproliferative activity against MCF7, which was found to be superior to free citric acid and free diosgenin. Least cell migration (approximately 40 %) on IONPs-D treatment supported its ability to inhibit motility of MCF7 cells as compared to both bare IONPs, and IONPs-CA. Confocal microscopy confirmed that IONPs-D and free diosgenin induced apoptosis which was evident from Alexa Fluor 488 annexin V/PI double-stained cells indicating extensive cell membrane damage coupled with PI influx leading to nuclear staining in treated cells. PARP cleavage was also observed among the treated cells. In view of this background, functionalized IONPs can be considered as novel magnetic nanomaterial with antiproliferative potential against cancer cells that can not only inhibit its migration but also induce apoptosis in breast cancer cells.

Bioactive principle functionalized nanomaterials for anticancer applications

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ACS Spring 2023

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