An understanding of film stability is useful in crafting predictable film morphologies, which have a wide range of applications extending from self-assembled nanostructures to coatings for engineered materials. The stability of a thin film on a solid support is affected by the nature of the thin film and the underlying substrate as well as their interactions. Thin films are commonly prepared by depositing organic solutions of nonpolar materials onto silicon wafer (SiO2); aqueous solutions are rarely used due to the destabilizing polar interactions during solvent evaporation leading to dewetting. In this study, hydrophilic and semi-crystalline poly(vinyl alcohol) (PVOH) thin films from aqueous solution were fabricated on SiO2 via spin casting. Experimental parameters including PVOH concentration, PVOH degree of hydrolysis, spin rate, and thermal annealing were probed. The PVOH thin films appeared to be continuous under all the conditions examined, demonstrating the stable nature of the PVOH-SiO2 system. The extensive hydrogen bonding between the films and the substrate as well as the crystallization within the thin films appear to play more dominant roles than the destabilizing polar interactions during solvent evaporation in dictating thin film stability.

Preparation of stable poly(vinyl alcohol) thin films from aqueous solution on silicon wafer

We report for the first time the use of electrocatalysis in differentiating DNA polymorphism. In the process of exploring electrocatalytic mechanism between ferricyanide (Fe(CN)63-) and methylene blue (MB), it is discovered that DNA probe dynamics play a role, in addition to the excess factor and the kinetic parameter. As dynamics of electrode-bound nucleic acid is often utilized as a mechanism in electrochemical nucleic acid-based sensors, we thus applied the electrocatalytic reaction in DNA sensing. The electrocatalytic DNA sensor consists of thiolated and methylene blue-labelled liner probe DNA. The electrocatalytic reaction begins with MB reduction, undergoing a two-electron reduction to leucomethylene blue (LMB) at sufficiently negative potentials. Before hybridization, due to the highly flexible DNA probe, MB can be reduced efficiently. The generated LMB reduces 2 equivalents of Fe(CN)63-, regenerating MB and thus results in a large catalytic current. In contrast, attenuated catalytic current is observed after hybridization, as MB reduction becomes sterically hindered. DNA polymorphism such as single-base mismatch, deletion, insertion, and DNA methylation can be differentiated based on the electrocatalytic sensor.

Electrocatalysis in differentiating DNA polymorphism

Hot and cold brew coffee samples brewed using Columbian coffee beans roasted at five different roast temperatures (174°C, 183°C, 194°C, 203°C, and 209°C) were analyzed. Caffeine concentration, total caffeoylquinic acid (CQA) concentration, total antioxidant activity, pH, total titratable acids, and total dissolved solids (TDS) were evaluated. Caffeine concentration ranged from 943.21 mg/L to 1055.60 mg/L and from 417.67 mg/L to 1147.59 mg/L for hot and cold samples respectively. Total CQA concentration ranged from 291.30 mg/L to 3213.21 mg/L and from 311.95 mg/L to 1648.47 mg/L for hot and cold samples respectively. In general, the hot brew method yielded higher caffeine and total CQA concentration than the cold brew method. Hot brew coffee samples exhibited a higher antioxidant capacity over cold brew coffee samples using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) decolorization assay. Coffee pH increased as roast temperature increased. At the same roast level, the pH between hot brew and cold brew coffee samples were comparable. The hot brew coffee samples were also found to have higher concentration of total titratable acids. Total dissolved solids (TDS) was observed to be greater in hot brew coffee samples than in cold brew counterparts. Increases in roasting temperature also led to an increase in TDS across coffee samples for both hot and cold brewing methods, with the highest TDS present in hot brew coffee samples roasted at 209°C. It is noted that with the exception of pH, all attributes of hot brew coffee samples have a direct relationship with roasting temperature, while increasing roast temperature exhibited an inverted u-shaped trend in the cold brew coffee samples. The results suggest that the bean roasting temperature significant impacts the chemistry of the final coffee brew and should not be ignored when crafting cold brew coffee beverages.

Role of roast on chemical characteristics of cold brew coffee

Proper oxidation modeling is essential in developing useful tests performed in a reasonably short time. It is shown that one of the assuptions utilized in modeling, called the constant substrate concentration hypothesis (CSCH), is a weak, unrealistic proposition that is incompatible with the generally accepted basic autoxidation scheme. More reliable results can be achieved when the CSCH is replaced by the inherent, easily understandable relation between the substrate and hydroperoxide concentrations. Furthermore, utilization of the latter relationship plays a key role in the development of the chemiluminescence (CL) methodology for the experimental assessment of two major oxidation parameters - the induction time and the oxidation rate constant. The intrinsic connection between the former parameter and the commonly used in practice graphically acquired oxidation induction time is demonstrated. The procedures presented in the study are applicable to both unstabilized and stabilized systems. Conducting the isothermal CL experiment on a series of the phenolic-stabilized PP samples at somewhat higher temperature (1600C) than the standard oven temperature (1500C) and under pure oxygen allowed us to keep good correlation with the oven testing results and, at the same time, essentially shorten duration of the test. Comparative study of a great variety of the ABS formulations revealed CL superior sensitivity and permitted experiments at significantly lower temperatures than differential scanning calorimetry (DSC). Consequently, the DSC oxidative stability data can be related to resistance to oxidation during processing while the CL results are expected to be useful in evaluating durability at service conditions.

Oxidation modeling and evaluation of the thermal oxidative stability by means of chemiluminescence

The Library of Congress holds nearly 200,000 reels of audio tape, spanning recordings of popular musicians, the American Folklife Center, and NPR broadcast archives. These tapes are generally comprised of a multilayer polyester-urethane material containing various additives and lubricants, and over the past few decades, many archival tapes have been observed to show signs of surface degradation resulting in unplayability. The most common treatment for an unplayable audio tape is a thermal remediation “baking” treatment where the tape is exposed to temperatures near 50 °C for multiple hours. While this thermal treatment usually succeeds in allowing for clean playback of the degraded tapes, the mechanisms underlying the thermal treatment have remained unclear. The Library’s Preservation Research and Testing Division has used modulated differential scanning calorimetry, heat-stage microscopy, and artificial aging to study the thermal transitions which occur during remedial tape baking. In most cases of tape degradation, crystalline polyester-like residues were observed on the surface of the tapes’ polymeric binder layer, and these residues were observed to melt back into the bulk polymer binder. However, as noted by seasoned audio technicians and archivists, thermal baking treatments are not permanent. Baked tapes are known to slowly revert back to unplayable condition. Additional time-based experiments identified phase separation in these treated tapes over time, with melted residues eventually blooming and re-appearing at the tape surface. Thermal transitions were also identified in both the magnetic layer and the PET support film, indicating that one single component cannot be attributed for tape breakdown and that the detrimental residues were not isolated to the tape binder layer. Learnings from these lab-scale experiments, undertaken on small samples of audio tape, are now being used on full-sized audio tape reels to understand how these thermal processed may proceed in tightly-wound real-world tapes to better inform preservation processes.

Towards understanding the thermal remediation of degraded archival reel-to-reel audio tapes

The elution behavior of bivalent bispecific antibodies (BiSAb) comprising an immunoglobulin G framework genetically fused to a pair of single chain variable fragments (scFvs) was studied on hydrophobic interaction chromatography (HIC) columns using ammonium sulfate gradients. Each of the BiSAb molecules studied exhibited a three-peak elution behavior regardless of the location of scFv attachment to the framework IgG. Collecting and re-injecting each of the isolated peaks and eluting with the same gradient resulted in the same three-peak profile indicating that the behavior is reversible. Analogous behavior was observed for HIC resins with different functional ligands, matrix structures, and particle sizes. Residence time, operating temperature, and hold time were shown, to affect the elution behavior. While three peaks were obtained at short residence times and room temperature, residence times longer than about 27 min or at 45 °C resulted in a single merged peak indicating that the underlying mechanism occurs on time scales comparable to that of chromatographic separation. Holding the protein on the resins prior to elution enriched the late eluting peak indicating that multiple binding states formed on the chromatographic surface are responsible for this behavior. Tryptophan autofluorescence measurements show that stronger binding forms have increased solvent exposure indicating that surface-catalyzed conformational changes play a role. A model was developed to describe the interplay of chromatographic separation and slow conformational changes.

Chromatographic behavior of bivalent bispecific antibodies on hydrophobic interaction chromatography columns

The water pollution due to oil and organic contaminants has emerged as a major environmental issue. Oil and organic pollution are contributed by various industries, household activities, and offshore oil production. History has witnessed some major devastating oil spill incidents during the rapid offshore oil movement. The oil-related contaminants can stay for a longer time and have a severe adverse effect on marine and human life. The conventional methods are facing problems due to their high cost, inefficiency, and source of secondary contaminants. There is a dire need to develop new efficient materials that can effectively separate the oil from water and has the capacity to scale up. One of the possible ways to separate the oil contaminants from the water by using porous hydrophobic and oleophilic surfaces. The hydrophobic and the oleophilic surfaces allow the passage of oil or non-polar organic contaminants from the water. The challenge associated with the development of hydrophobic surfaces is the complexity in synthesis and its stability. Synthesis of material through the naturally available sources is always attractive. The natural sunlight is an abundant natural source that carried out the great potential to drive the chemical reactions under a certain set of conditions. We built an amazing cost-efficient synthetic route by harvesting the natural sunlight to develop the hydrophobic surfaces that allowed the fast passage of the oil and prevented the water to pass. This was achieved by introducing the glass reactor and the suitable monomer that display the capacity to polymerize under the sunlight radiations. In brief, hydrophobic surfaces were prepared by harvesting the natural sunlight that initiated the polymerization of the styrene on the selected porous substrate in a glass reactor. This provides an extremely cost-effective route to prepare the hydrophobic surfaces. The surface area can be improved by adding various nanomaterials. The surfaces prepared by through this route can display the contact angle in the range of 126 ± 4° to 161° ± 2° according to the functionalities. The separation efficiency can be achieved for the various oil/water-based system in the range of 96 to 99 %. The developed porous materials can be used for the continuous separation of the oil spills and the spot absorption of the oil from the water.

Oil/water separation by using the photopolymerized porous hydrophobic and oleophilic materials

Many different pedagogical techniques have been implemented to determine what students understand in real time in the classroom. The goal of this study was to investigate the accuracy of student self-assessments regarding what they know and do not know about muddiest point topics presented at the end of the lecture. This study investigated two sections of General Chemistry I and one section of General Chemistry II. During the two terms, clickers were used to collect muddiest point information in the chemistry classroom. The muddiest point clicker questions give students an opportunity to reflect on their learning and provide feedback to the instructor. Student responses were compared to a follow-up clicker question asked at the start of the following lecture. The results of this study were consistent with the Dunning-Kruger effect, in that high-performing students were more accurate in their self-assessment than low-performing students. When inaccurate, high-performing students tended to underestimate their understanding of a topic. Low-performing students who were inaccurate in their self-assessment tended to overestimate their understanding of a topic. The accuracy of student self-assessments was analyzed as a function of topic type: quantitative vs. qualitative and broad vs. specific.

Investigating the accuracy of student self-assessment on muddiest point questions

Fast scan cyclic voltammetry (FSCV) and carbon-fiber microelectrodes (CFMEs) have been utilized used to detect several important neurochemicals in vivo. However, this method is limited due to the ability to discriminate dopamine from several of its metabolites. Carbon nanotube and polymer modified microelectrodes will be utilized to detect physiologically low levels of neurotransmitters that also resist surface fouling and have high temporal resolution to detect fast changes of neurotransmitters. Furthermore, novel electrode coatings and waveforms will also be utilized to detect several neurotransmitter metabolites such as dopamine, norepinephrine, normetanephrine, 3-methoxytyramine (3-MT), homovanillic acid (HVA), 3,4 dihydroxyphenylacetic acid (DOPAC), and other metabolites. Currently, dopamine is thought to be an important neurotransmitter concerning several disease states such Parkinson’s disease, drug abuse (amphetamine, cocaine, etc.), and even for gambling and sex-disorders. However, dopamine is metabolized on a subsecond timescale, and studies have pointed to the importance of neurotransmitter metabolites in these disease states apart from dopamine. Presently, there is no method to selectively co-detect these neurotransmitter metabolites of dopamine utilizing FSCV. Through several waveform modifications and polymer electrode coatings, we develop a novel method to tune the detection of dopamine and said metabolites, which will help differentiate dopamine and respective metabolites through the shapes and positions of their respective cyclic voltammograms. Preliminary measurements have also been made in zebrafish whole brain ex vivo showing the application of this technique in biological tissue. Discriminating the detection of dopamine from its metabolites will have many implications in better understanding complex disease, behavioral, and pharmacological states.

Differentiation and detection of dopamine monoamine metabolites with carbon fiber-microelectrodes and fast scan cyclic voltammetry

Protein arginine methyltransferase 5 (PRMT5) is an important epigenetic enzyme involved in cancer development. It carries out symmetric dimethylation on histone proteins, especially on H4R3, utilizing S-adenosyl-L-methionine (SAM) as a cofactor. PRMT5 is overexpressed in a variety of cancers, especially MTAP-deleted cancers, making it a compelling target for anticancer therapeutics. Here, we report an apo structure of the human PRMT5:MEP50 complex determined at a resolution of 3.4 Å by single-particle cryo-EM. The intrinsic flexibility of the loop region (residues 292–329) at the active site of apo-PRMT5:MEP50 suggests a huge conformational change induced by the binding of a nucleoside-containing molecule at the cofactor-binding site. Based on the structural feature of apo-PRMT5:MEP50, we have optimized our carbazole-based lead compound CMP5 into peptide-competitive inhibitors (e.g. 11-1F, 11-2F and 11-9F) that bind to the substrate-binding site in the presence of a nucleoside-containing molecule, such as 5’-methylthioadenosine (MTA), binding at the cofactor-binding site. The enzyme inhibition IC50 of compound 11-1F was determined in MTase-Glo assays at 1.3 μM, and its mechanism of inhibition was confirmed as SAM-uncompetitive and peptide-competitive. The cryo-EM structure of PRMT5:MEP50 bound with MTA and 11-2F (IC50 = 0.9 μM) was determined at a resolution of 3.3 Å. By structure-based drug design and SAR analysis, we have identified compound 11-9F as a potent and selective inhibitor with an IC50 value of 183 nM. Here we describe the design and characterization of 11-9F as a peptide-competitive, MTA- synergistic PRMT5 inhibitor with anti-proliferative effects in several breast cancer cell lines. Protein-inhibitor binding experiments were performed by Surface Plasmon Resonance (SPR) to analyze the binding preference of 11-9F towards apo and SAM/SAH/MTA-bound forms of PRMT5:MEP50 and the binding affinity KD values were determined. 11-9F showed stabilization of PRMT5 in cellular thermal shift (CETSA) target engagement assay and the melting temperature was shifted by ~2 °C. Treatment of 11-9F with or without MTA in breast cancer cell lines led to inhibition of symmetric dimethylation and cell death with IC50 values in the single-digit micromolar range. The in vivo evaluations are currently underway.

Structural and biochemical study of human PRMT5 and its peptide–competitive MTA–synergistic small molecule inhibitors for cancer therapeutics

The production of chocolate products is a global industry that needs a method to determine the geographic origins of its most essential component, cocoa. Traceability of cocoa is becoming more important for quality control in the chocolate industry, so that consumers can know they are purchasing products that adhere to fair-trade regulations, organic farming practices, etc. Many of the steps in the process of producing cocoa can influence the chemical makeup of the different aspects of the final product including the flavor profile and aroma. Each region where cocoa is gown has variations in soil composition, weather and farming practices that influence the cocoa bean development. Additionally, differences in post-harvest treatments including fermentation and roasting conditions influence the overall chemical composition of the resulting cocoa liquor used to make finished chocolate products. These differences result in unique chemical signatures that can identify cocoa liquors by their country of origin. Many studies have employed GC/MS, ICP/MS, and HPLC to quantify and detect the presence of certain classes of compounds in cocoa, but there are fewer studies focused on provenance determination via chemical signatures. Previous work by this group has been able to accurately determine the country of origin of cocoa samples using ICP/MS to construct a unique elemental profile for each country. Use of LC/MS provides an opportunity to evaluate a wide variety of molecules for generating chemical signatures. The cocoa sample preparation and conditions for UPLC/ESI-TOFMS used to obtain unique chemical signatures from cocoa liquor samples are described. Several classes of compounds were identified from the mass spectral data, and the semi-quantitative analysis method was verified with a cocoa standard reference material. Discriminate analysis was used to identify cocoa liquor samples from five different countries. The method was able to accurately group and identify country of origin in 95% of samples. Future directions include moving beyond country level provenance determination, to regional discrimination within countries, and potentially differences in signatures due to genetic strains of cacao.

Chemical signatures from UPLC/MS for cocoa provenance determination

Per- and polyfluoroalkyl substances (PFAS) are class of thousands of synthetic fluorinated organic chemicals that have unique beneficial chemical and mechanical attributes including chemical and thermal stability. Thus, they have been used in a wide variety of industrial and commercial applications including aqueous film forming foams (AFFFs). Use of AFFFs by firefighters to extinguish hydrocarbon fires tends to contaminate water and soil with PFAS near application sites. Furthermore, several groups of PFAS have been detected in the blood serum of firefighters that have been exposed to AFFFs. Exposure to PFAS can lead to adverse health outcomes in humans. Although dermal exposure may be one route for their presence in the serum, inhalation of volatile PFAS could be another major contributor, however, less is known about the volatile PFAS released by AFFFs. The primary objective of this study is to determine the presence of volatile PFAS in the headspace of AFFF concentrates.  We investigated the presence of volatile PFAS in the headspace above agitated AFFF using two analytical techniques. One method utilized polyurethane foam and XAD resin with liquid chromatography mass spectrometry to quantify 30 PFAS. A second, more exploratory approach used a thermal desorption sampler and gas chromatography mass spectrometry to measure 22 PFAS.  16 PFAS were detected in the headspace including 5 fluorotelomer alcohols (1.1 to 38.1 ng/L), 10 perfluorinatedperflourinated carboxylic acids (1.2 to 13,668 ng/L) and 1 fluorotelomer sulfonate (72.1 ng/L). The most abundant PFAS detected in the headspace was perfluorooctanoic acid (13,668 ng/L). Additionally, a total of five saturated, iodinated, and ethenyl fluorocarbons were identified, which may be derived in the AFFF manufacturing process as precursors to other PFAS. The results of this research provide novel information about identity, concentration and rate of volatile PFAS released by AFFFs concentrates.

Volatile per- and polyfluoroalkyl substances released from aqueous film-forming foam

Marijuana is listed as a Schedule I substance under the American Controlled Substances Act of 1970. As more U.S. states and countries beyond the U.S. seek legalization, demands grow for identifying individuals driving under the influence (DUI) of marijuana. Currently no roadside DUI test exists for determining marijuana impairment, thus the merit lies in detecting the primary and the most sought psychoactive compound tetrahydrocannabinol (THC) in marijuana. Salivary THC levels are correlated to blood THC levels making it a non-invasive medium for rapid THC testing. Affinity biosensing is leveraged for THC biomarker detection through the chemical reaction between target THC and THC specific antibody to a measure signal output related to the concentration of the targeted biomarker. Here, we propose a novel, rapid, electrochemical biosensor for the detection of THC in saliva as a marijuana roadside DUI test with a lower detection limit of 1200 picogram per milliliter and a dynamic range ranging from 100 picogram per milliliter to 100 nanogram per milliliter in human saliva. The developed biosensor is the first of its kind to utilize affinity-based detection through impedimetric measurements with a rapid detection time of less than a minute. Fourier transform infrared spectroscopy analysis confirmed the successful immobilization of the THC immobilization assay on the biosensing platform. Zeta potential studies provided information regarding the stability and the electrochemical behavior of THC immunoassay in varying salivary pH buffers. We have demonstrated stable, dose dependent biosensing in varying salivary pH’s. The biosensor on integration with low-power electronics and a portable saliva swab serves as a roadside DUI hand-held platform for rapid identification of THC in saliva samples obtained from human subjects.

Rapid response electrochemical biosensor for detecting THC in saliva

Many ceramic coatings contain high levels of heavy metal elements as colorants that are environmentally unfriendly and toxic to users. Metallic nanoparticles, including gold and silver, have been proposed as an alternative to these metal colorants due to their versatile color profiles, benign nature, and more efficient color mechanism via surface plasmon resonance. This research explores the effects of common ceramic sintering processes on nanoparticles within glazes in common studio reductive and oxidative kilns. This work also employs direct application of gold and silver salts in glazes to probe and better understand the mechanistic processes for nanoparticle-laced glazes that are viable in the art community. These processes avoid the need for complicated reductants, glassware, or preliminary heating elements, thus allowing for environmentally friendlier yet economically viable applications of nanoparticle colorants.

Nanoparticles as ceramic glaze colorant alternatives

Acetophenone was reduced using sodium borohydride to recieve the product, 1-phenylethanol. The reaction was performed using mechanochemistry without a solvent to improve green chemistry of the reaction. This is designed to reduce the amount of waste and improve energy efficiency. The reaction creates a new chiral center where the hydroxl group replaces the carbonyl group. In many applications, including the pharmaceutical community, there is a demand for control of chirality. Enantiomers can affect varying physiological pathways and lead to vastly different adverse effects on a cell which might not be competent to respond to the drug as intended. Biomolecules such as starch, glucose, and agar were investigated as chiral auxiliaries in the reduction under mechanochemical conditions.

Solvent-free asymetric reduction of acetophenone to 1-phenylethanol with sodium borohydride using mechanochemistry

Autodock Vina (AD Vina) is a widely used and freely available software for molecular docking to predict protein-ligand interaction. However, AD Vina is limited to run in CPU environment, although it provides the parallel docking in high performance computing. Recently, GPU-accelerated computing becomes more accessible in molecular simulations such as molecular dynamics. Here, we introduce a GPU-accelerated Autodock Vina, called Viking (Standigm Vina Docking on GPU). We ported the orginal Vina code and optimized it to run on GPU environment. Based on the analysis of the Vina code, it revealed most time determining process of Vina was the “pose search” which is expected. Therefore, we re-wrote “pose search” in order to be run on GPU processor for parallelization. In the application, we performed cross-docking application to identify ligand protein interactions predictions which typically require very large docking calculation. For example, a single query ligand for the cross-docking requires more than 10K docking calculations which correspond to the number of target proteins having 3D X-ray structures. We expect the Viking has capability of docking more than 100K ligands on a single standalone computing environment which is faster than an order of magnitude of the original Autodock Vina.

GPU-accelerated autodock vina: Viking

Point-scan 3D fluorescence imaging requires long acquisition times due to the large number of voxels which must be scanned when using the conventional method where a motorized stage is stepped between image planes to acquire raster-scanned frames in sequence. Introduction of a continuous focal change during the frame scanning process creates 3D patterns which are repeatable and tile without multiply sampling voxels when appropriately timed. The sparse distribution of scanned voxels when using this pattern enables incompletely scanned volumes to be interpolated to completion using an inpainting algorithm. This method, called 3D Fast Acquisition Scan via z-Translating Raster (3D-FASTR) is shown to provide up to a 4x speed increase as compared to conventional stage-step acquisition. This theoretical framework was implemented into a modified commercial confocal microscope using an ultrafast laser for two-photon excitation and an electrically-tunable lens to implement this method and image live cells and capture diffusive motion in 3D.

Speeding up 3D laser scanning fluorescence microscopy for live cell imaging

Development for refreshable braille devices has recently shifted to electroactive polymers (EAP). This paradigm benefits from greater precision, smaller size, and lower cost associated with modern electronics, opening the door for higher resolution and less expensive devices. Displays with resolution finer than required to display braille characters will enable representation of non-text information such as figures, tables, or diagrams. However, adoption of EAPs for responsive displays has encountered problems such as high required field strength (kV/cm), insufficient pressure (2 kPa generated), and poor durability. This work presents a new type of electroactive polymers, based on poly ionic complexes. In contrast to previously reported electroactive polymers, these gels do not rely on a solvent bath, respond to a field that is on the order of V/cm, and expand in a direction parallel to the applied electric field. Ultimately, the expansion is driven by electrostatic interactions: The polyionic gels are overall charge neutral, however, when an electric field of sufficient strength is applied, the ionic bonds are broken and the polycation is drawn towards the plate. This reveals the charged backbone of both the polyanions and the polycations, which causes the repeat units to repel one another and the gel to expand. This mechanism is confirmed using cyclic voltammetry and impedance spectroscopy. With the understanding of the mechanism, the gels are made to expand rapidly and tolerate 100s of cycles. These properties are controlled through the identity of the ionic repeat units and further tuning the crosslinking and processing of the gels. The ionic crosslinks within the gel impart desirable qualities such as self-healing and high toughness a through a cooperative effect, yielding durable gels that are the much stronger than their component parts. The low power requirements and resilient nature of these EAPs make them attractive for use as refreshable braille displays. This methodology could be adapted to other actuators such as soft robotic joints or grippers.

Durable, low-voltage electroactive polymers formed from polyionic complexes

Coffee adulteration and declining supply of quality coffee create a tremendous pressure for the industry to sustain the escalating (3.2 billion-kg, currently) global coffee demand. Widespread adulteration becomes more prevalent along the commercial chain as a strategy to gain profit causing negative economic impact. Moreover, adulterated coffee causes significant roasting and brewing inconsistencies resulting in poor product quality and sensory characteristics. Thus, effective analytical tools for detecting adulterated coffee are a critical need for the coffee industry. To address this challenge, we developed a high-throughput and on-line SIFT-MS based analytical system for the authentication and adulteration analysis of coffee beans from single geographical origins. Single-origin green coffee beans (16 commercial varieties) from South America, Africa, Asia, and Pacific Hawaii, were roasted (230±3oC) using a drum-type roaster. Off-gas volatile compounds were measured in real-time during the entire roasting duration (25 min) using an online SIFT-MS with 15 to 220 m/z+ mass spectral range for each H3O+, NO+, and O2+ ion reaction channels. The air temperature in the roasting chamber and off-gas vents were monitored using K- and T-type thermocouples. Using time-series data analysis, emission profiles were characterized and key masses were identified for differentiating coffee types and origin-based cultivars. Classification model schemes were subsequently developed to classify coffee beans by origin and type (Arabica or Robusta) using Principal Component Analysis and Discriminant Analysis. Emission profiles revealed that specific volatile compounds form and decay at different times during roasting and that the occurrence and intensity of a compound’s peak maxima or plateau were variety-specific. Such information are key discriminant factors and basis for building predictive classification model schemes for a high throughput analysis of adulteration and authentication of single-origin coffee beans. Thus, online SIFT-MS is an effective analytical tool for the real-time analysis of volatile compounds during coffee roasting.

Novel detection of adulteration and authentication of single-origin coffee beans using on-line selected-ion flow tube-mass spectrometry (SIFT-MS)

Coordination compounds with 1,2-ethylenediamine (en) ligands have played vital roles in the development of inorganic chemistry and stereochemistry. Nobel laureate Alfred Werner synthesized and resolved both enantiomers of [Co(en)3]3+ into their respective Λ and Δ forms over a century ago. Despite this rich background, these complexes have remained dormant in terms of synthetic utility until recently. This is largely due to the strong field amine ligands that are difficult to displace and their low spin d6 electron configuration, rendering these octahedral complexes kinetically substitution inert. Conversely, these attributes, in addition to the quantity and quality of NH units, lend Werner complexes to serve as effective chiral H-bond donating catalysts, featuring potential applications in the synthesis of pharmaceuticals and agrichemicals. Central to this goal are the anion metathesis reactions conducted for the substitution of commonly paired halide anions with lipophilic anions. These reactions enhance the solubility of the complexes in organic solvents and decrease the competition between anions and substrates for NH donor sites. Amongst the latest discoveries, lipophilic cobalt cage complexes have led us to deduce that high enantioselectivity is predicated on the substrates’ ability to hydrogen bond with the C3 faces of the catalysts. Additionally, the variation of [M(en)3]n+ to include Mn+ = Cr3+, Rh3+, Ir3+, and Pt4+ has furnished complexes with variable thermal stabilities. Finally, the ligands have been further decorated with functionalized phenyl rings via simple, stereospecific synthetic routes resulting in catalysts with a breadth of steric bulk, NH unit acidities, and solubility profiles.

Syntheses of Werner complexes: Applications as chiral hydrogen bond donors in enantioselective catalysis

Hybridization of atomic orbitals to form hybrid orbitals is a tough concept for students to grasp. Until recently, instructors have been limited to how they could illustrate this abstract model. Predominantly static 2-dimensional images have been used. More creative methods utilized balloons or toothpicks and marshmallows to help students with the 3-dimensional aspects. With the widespread availability of touch-screen devices and the rise in use of online textbooks, Alchemie saw the opportunity to develop a hybridization explorer. This explorer has three modes, present, explore, and assess. In the present mode, students are able to view atomic or hybrid orbitals and rotate them. In the explore mode, students choose atomic orbitals then select hybridize to morph into a visual of resulting hybrid orbitals. In the assess mode students are given various prompts and have to form the correct hybrid orbital in response. The goal of this interactive is to lead to a more intuitive understanding of the geometrical and bonding explanations that result from hybridization theory. In this poster, the features of the hybridization explorer will be presented. Additionally, initial research into the impacts of the explorer on student understanding will be presented.

From the abstract to manipulable: Impacts of a touch-screen based hybridization explorer

Estrogens are known endocrine-disrupting agents which have emerged as a class of pollutants that pose danger to aquatic organisms at low concentrations. Among their negative impacts on aquatic life is their effect on reproductive behavior, which can ultimately move up trophic levels of the ecosystem resulting in a compounding environmental effect. Estrogenic compounds detected in wastewater effluents and surface water at nanogram to picogram per liter concentrations include estrone (E1), 17β-estradiol (E2), 17α-ethinylestradiol (EE2), and estriol (E3). Despite their known risks, concentrations in the Northeastern United States have remained largely unknown. We have developed and validated an SPE-GC-MS method for the quantification of these estrogenic compounds in the Whippany River and Loantaka Brook (NJ, USA). Estrogens extracted from water samples via SPE are subsequently derivatized using BSFTA + 2% TMCS and successfully separated and quantified at ppb levels using this GC-MS method.

Quantification of estrogenic compounds by SPE-GC-MS in New Jersey natural and wastewater sources

Artificial intelligence has emerged in many areas of pharmaceutical research, particularly in early drug discovery, such as bioactivity prediction, retrosynthetic reaction prediction, and de novo drug design. Parkinson’s disease is a movement disorder by impairment of nerve cells. The leucine-rich repeat kinase 2 (LRRK2) mutations are a major cause of inherited PD, however only a few drugs are reported in early clinical trials. In the present study, we employed a deep generative model to identify potent (LRRK2) inhibitors for PD treatment. To enable this, we developed an automated workflow with minimal human assistance. The workflow consists of four steps; 1)training chemical structural features with bioactivities, 2)generating structures, 3)filtering with novelty check, 4)post-processing for structure prioritization for screening. In the results, ~1600 known LRRK2 inhibitors are compiled from ChEMBL for training and we successfully generated ~40,000 novel structures. We then performed docking screening to prioritize compounds and finally selected 11 compounds. One of the potential hit compounds exhibited only Tanimoto coefficient of 0.4 with reported LRRK2 inhibitors. The selected 11 compounds were synthesized and currently being biological evaluated in vitro.

De novo drug design with AI in the application to identify potent LRRK2 inhibitors

Research on the use of transition metal (TM) complexes for the reduction of dinitrogen has proliferated in recent years. In particular, great progress has been made in the past decade in the use of pincer-ligated TM complexes in this context. Such complexes, however, have required ‘pre-activation’ by a strong reducing agent like Na/Hg or KC8 to achieve reductive N2 splitting. In this study, non-innocent pincer molybdenum(III) trihalide complexes, (PhPN5P)MoCl3 and (tBuPPHP)MoBr3, bearing acidic E–H (E = N or P) protons on the ligand periphery, have been utilized to investigate deprotonative N2 splitting. These complexes can be activated in the presence of KOtBu, without the need for a strong reductant. Reaction with KOtBu presumably affords (PhPN5P*)MoCl2 and (tBuPPP)MoBr2 respectively, through the loss of HX across the E-M bond. N2 binding at the vacant coordination site on the metal is followed by splitting of N2 to afford nitrides (PhPN5P*)MoVI(N)Cl2 and (tBuPPP)MoV(N)Br. Previous studies have demonstrated the reduction of molybdenum nitrides to ammonia in the presence of chemical reductants and proton sources but little is known about the relative reactivity of various nitrides and the detailed sequence of events leading to ammonia formation and regeneration of the active species. We, therefore, have begun an investigation of such catalytic cycles for ammonia formation. Mechanistic studies of the new complex (iPrPSP)Mo and of Nishibayashi’s (tBuPNpyP)Mo systems, including DFT and electrochemical studies, revealed characteristic roles of the halides in splitting dinitrogen. A new pathway leading to the formation of ammonia and regeneration of the catalyst was elucidated.

(PXP)Mo pincer complexes for catalytic dinitrogen reduction: Synthesis, characterization and mechanistic studies

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