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Full-Text Articles in Physical Sciences and Mathematics

Mitocans Induce Lipid Flip-Flop And Permeabilize The Membrane To Signal Apoptosis, Stuart R. Castillo, Michael H.L. Nguyen, Mitchell Dipasquale, Elizabeth G. Kelley, Drew Marquardt Jun 2023

Mitocans Induce Lipid Flip-Flop And Permeabilize The Membrane To Signal Apoptosis, Stuart R. Castillo, Michael H.L. Nguyen, Mitchell Dipasquale, Elizabeth G. Kelley, Drew Marquardt

Chemistry and Biochemistry Publications

Pancratistatin (PST) and narciclasine (NRC) are natural therapeutic agents that exhibit specificity toward the mitochondria of cancerous cells and initiate apoptosis. Unlike traditional cancer therapeutic agents, PST and NRC are effective, targeted, and have limited adverse effects on neighboring healthy, noncancerous cells. Currently, the mechanistic pathway of action for PST and NRC remains elusive, which in part inhibits PST and NRC from becoming efficacious therapeutic alternatives. Herein, we use neutron and x-ray scattering in combination with calcein leakage assays to characterize the effects of PST, NRC, and tamoxifen (TAM) on a biomimetic model membrane. We report an increase in lipid …


Boron Neutron Capture Therapy In The New Age Of Accelerator-Based Neutron Production And Preliminary Progress In Canada, Dominik Dziura, Sana Tabbassum, Amanda Macneil, Dalini D. Maharaj, Robert Laxdal, Oliver Kester, Ming Pan, Hiroaki Kumada, Drew Marquardt Jun 2023

Boron Neutron Capture Therapy In The New Age Of Accelerator-Based Neutron Production And Preliminary Progress In Canada, Dominik Dziura, Sana Tabbassum, Amanda Macneil, Dalini D. Maharaj, Robert Laxdal, Oliver Kester, Ming Pan, Hiroaki Kumada, Drew Marquardt

Chemistry and Biochemistry Publications

Each year more than 3000 Canadians are diagnosed with brain cancers like glioblastoma multiforme or recurrent head and neck cancers, which are difficult to treat with conventional radiotherapy techniques. One of the most clinically promising treatments for these cancers is boron neutron capture therapy (BNCT). This procedure involves selectively introducing a boron delivery agent into tumor cells and irradiating them with a neutron beam, which kills the cancer cells due to the high-linear energy transfer radiation produced by the 10B(n,α)7Li capture reaction. The theory of BNCT has been around for a long time since 1936, but has historically been limited …


Investigating The Effect Of Medium Chain Triglycerides On The Elasticity Of Pulmonary Surfactant, Maksymilian Dziura, Stuart R. Castillo, Mitchell Dipasquale, Omotayo Gbadamosi, Piotr Zolnierczuk, Michihiro Nagao, Elizabeth G. Kelley, Drew Marquardt Apr 2023

Investigating The Effect Of Medium Chain Triglycerides On The Elasticity Of Pulmonary Surfactant, Maksymilian Dziura, Stuart R. Castillo, Mitchell Dipasquale, Omotayo Gbadamosi, Piotr Zolnierczuk, Michihiro Nagao, Elizabeth G. Kelley, Drew Marquardt

Chemistry and Biochemistry Publications

In recent years, vaping has increased in both popularity and ease of access. This has led to an outbreak of a relatively new condition known as e-cigarette/vaping-associated lung injury (EVALI). This injury can be caused by physical interactions between the pulmonary surfactant (PS) in the lungs and toxins typically found in vaping solutions, such as medium chain triglycerides (MCT). MCT has been largely used as a carrier agent within many cannabis products commercially available on the market. Pulmonary surfactant ensures proper respiration by maintaining low surface tensions and interface stability throughout each respiratory cycle. Therefore, any impediments to this system …


Investigating The Cut-Off Effect Of N-Alcohols On Lipid Movement: A Biophysical Study, Michael H.K. Nguyen, Dominik Dziura, Mitchell Dipasquale, Stuart R. Castillo, Elizabeth G. Kelley, Drew Marquardt Jan 2023

Investigating The Cut-Off Effect Of N-Alcohols On Lipid Movement: A Biophysical Study, Michael H.K. Nguyen, Dominik Dziura, Mitchell Dipasquale, Stuart R. Castillo, Elizabeth G. Kelley, Drew Marquardt

Chemistry and Biochemistry Publications

Cellular membranes are responsible for absorbing the effects of external perturbants for the cell’s survival. Such perturbants include small ubiquitous molecules like n-alcohols which were observed to exhibit anesthetic capabilities, with this effect tapering off at a cut-off alcohol chain length. To explain this cut-off effect and complement prior biochemical studies, we investigated a series of nalcohols (with carbon lengths 2-18) and their impact on several bilayer properties, including lipid flip-flop, intervesicular exchange, diffusion, membrane bending rigidity and more. To this end, we employed an array of biophysical techniques such as time-resolved small angle neutron scattering (TRSANS), small angle X-ray …


Guanidinium–Amino Acid Hydrogen-Bonding Interactions In Protein Crystal Structures: Implications For Guanidinium-Induced Protein Denaturation, Indu Negi, Raman Jangra, Amit Gharu, John F. Trant, Purshotam Sharma Dec 2022

Guanidinium–Amino Acid Hydrogen-Bonding Interactions In Protein Crystal Structures: Implications For Guanidinium-Induced Protein Denaturation, Indu Negi, Raman Jangra, Amit Gharu, John F. Trant, Purshotam Sharma

Chemistry and Biochemistry Publications

In the present work, 86 available high resolution X-ray structures of proteins that contain one or more guanidinium ions (Gdm+) are analyzed for the distribution and nature of noncovalent interactions between Gdm+ and amino-acid residues. A total of 1044 hydrogen-bonding interactions were identified, of which 1039 are N–H⋯O, and five are N–H⋯N. Acidic amino acids are more likely to interact with Gdm+ (46% of interactions, 26% Asp and 20% Glu), followed by Pro (19% of interactions). DFT calculations on the identified Gdm+–amino acid hydrogen-bonded pairs reveal that although Gdm+ interacts primarily with the backbone amides of nonpolar amino acids, Gdm+ …


A Nanodiamond Chemotherapeutic Folate Receptor-Targeting Prodrug With Triggerable Drug Release, Jiangtao Wu, Xiangbin Du, Dongmei Zhang, Jicheng Cui, Xiaoxia Zhang, Xine Duan, John F. Trant, Yingqi Li Nov 2022

A Nanodiamond Chemotherapeutic Folate Receptor-Targeting Prodrug With Triggerable Drug Release, Jiangtao Wu, Xiangbin Du, Dongmei Zhang, Jicheng Cui, Xiaoxia Zhang, Xine Duan, John F. Trant, Yingqi Li

Chemistry and Biochemistry Publications

No abstract provided.


Vitamin E Does Not Disturb Polyunsaturated Fatty Acid Lipid Domains, Mitchell Dipasquale, Michael H.L. Nguyen, Stuart R. Castillo, Isabelle J. Dib, Elizabeth G. Kelley, Drew Marquardt Nov 2022

Vitamin E Does Not Disturb Polyunsaturated Fatty Acid Lipid Domains, Mitchell Dipasquale, Michael H.L. Nguyen, Stuart R. Castillo, Isabelle J. Dib, Elizabeth G. Kelley, Drew Marquardt

Chemistry and Biochemistry Publications

The function of vitamin E in biomembranes remains a prominent topic of discussion. As its limitations as an antioxidant persist and novel functions are discovered, our understanding of the role of vitamin E becomes increasingly enigmatic. As a group of lipophilic molecules (tocopherols and tocotrienols), vitamin E has been shown to influence the properties of its host membrane, and a wealth of research has connected vitamin E to polyunsaturated fatty acid (PUFA) lipids. Here, we use contrast-matched small-angle neutron scattering and differential scanning calorimetry to integrate these fields by examining the influence of vitamin E on lipid domain stability in …


Partial Volumes Of Phosphatidylcholines And Vitamin E: Α-Tocopherol Prefers Disordered Membranes, Mitchell Dipasquale, Michael H.L. Nguyen, Georg Pabst, Drew Marquardt Sep 2022

Partial Volumes Of Phosphatidylcholines And Vitamin E: Α-Tocopherol Prefers Disordered Membranes, Mitchell Dipasquale, Michael H.L. Nguyen, Georg Pabst, Drew Marquardt

Chemistry and Biochemistry Publications

Despite its discovery over 95 years ago, the biological and nutritional roles of vitamin E remain subjects of much controversy. Though it is known to possess antioxidant properties, recent assertions have implied that vitamin E may not be limited to this function in living systems. Through densitometry measurements and small-angle X-ray scattering we observe favorable interactions between α-tocopherol and unsaturated phospholipids, with more favorable interactions correlating to an increase in lipid chain unsaturation. Our data provide evidence that vitamin E may preferentially associate with oxygen sensitive lipids-an association that is considered innate for a viable membrane antioxidant.


The Total Synthesis Of Glycolipids From Streptococcus Pneumoniae And A Re-Evaluation Of Their Immunological Activity**, Seyed Iraj Sadraei, Greg Yousif, S. Maryamdokht Taimoory, Maryam Kosar, Samaneh Mehri, Raghd Alolabi, Emmanuel Igbokwe, Jason Toma, Mir Munir A. Rahim, John F. Trant Jul 2022

The Total Synthesis Of Glycolipids From Streptococcus Pneumoniae And A Re-Evaluation Of Their Immunological Activity**, Seyed Iraj Sadraei, Greg Yousif, S. Maryamdokht Taimoory, Maryam Kosar, Samaneh Mehri, Raghd Alolabi, Emmanuel Igbokwe, Jason Toma, Mir Munir A. Rahim, John F. Trant

Chemistry and Biochemistry Publications

Invariant natural killer (iNK) T cells, Type I iNKTs, are responsible for the production of pro-inflammatory cytokines which induce a systemic immune response. They are distinctive in possessing an semi-invariant T-cell receptor that recognizes glycolipid antigens presented by CD1d, a protein closely related to the class I major histocompatibility complex, conserved across multiple mammalian species in a class of proteins well-renowned for their high degree of polymorphism. This receptor's first potent identified antigen is the α-galactosylceramide, KRN7000, a synthetic glycosphingolipid closely related to those isolated from bacteria that were found on a Japanese marine sponge. A corresponding terrestrial antigen remained …


The Interaction And Orientation Of Peptide Kl4 In Model Membranes, Drew Marquardt, Brad Van Oosten, Maksymilian Dziura, Joanna R. Long, Thad A. Harroun Jul 2022

The Interaction And Orientation Of Peptide Kl4 In Model Membranes, Drew Marquardt, Brad Van Oosten, Maksymilian Dziura, Joanna R. Long, Thad A. Harroun

Chemistry and Biochemistry Publications

We report on the orientation and location of synthetic pulmonary surfactant peptide KL4, (KLLLL)4K, in model lipid membranes. The partitioning depths of selectively deuterated leucine residues within KL4 were determined in DPPC:POPG (4:1) and POPC:POPG (4:1) bilayers by oriented neutron diffraction. These measurements were combined with an NMR-generated model of the peptide structure to determine the orientation and partitioning of the peptide at the lipid–water interface. The results demonstrate KL4 adopting an orientation that interacts with a single membrane leaflet. These observations are consistent with past 2H NMR and EPR studies (Antharam et al., 2009; Turner et al., 2014).


Probing The Link Between Pancratistatin And Mitochondrial Apoptosis Through Changes In The Membrane Dynamics On The Nanoscale, Stuart R. Castillo, Brett W. Rickeard, Mitchell Dipasquale, Michael H.L. Nguyen, Aislyn Lewis-Laurent, Milka Doktorova, Batuhan Kav, Markus S. Miettinen, Michihiro Nagao, Elizabeth G. Kelley, Drew Marquardt Jun 2022

Probing The Link Between Pancratistatin And Mitochondrial Apoptosis Through Changes In The Membrane Dynamics On The Nanoscale, Stuart R. Castillo, Brett W. Rickeard, Mitchell Dipasquale, Michael H.L. Nguyen, Aislyn Lewis-Laurent, Milka Doktorova, Batuhan Kav, Markus S. Miettinen, Michihiro Nagao, Elizabeth G. Kelley, Drew Marquardt

Chemistry and Biochemistry Publications

Pancratistatin (PST) is a natural antiviral alkaloid that has demonstrated specificity toward cancerous cells and explicitly targets the mitochondria. PST initiates apoptosis while leaving healthy, noncancerous cells unscathed. However, the manner by which PST induces apoptosis remains elusive and impedes the advancement of PST as a natural anticancer therapeutic agent. Herein, we use neutron spin-echo (NSE) spectroscopy, molecular dynamics (MD) simulations, and supporting small angle scattering techniques to study PST's effect on membrane dynamics using biologically representative model membranes. Our data suggests that PST stiffens the inner mitochondrial membrane (IMM) by being preferentially associated with cardiolipin, which would lead to …


Naphthalene-Functionalized Resorcinarene As Selective, Fluorescent Self-Quenching Sensor For Kynurenic Acid†, Anna Karle, Kwaku Twum, Noorhan Sabbagh, Alise Haddad, S. Maryamdokht Taimoory, Małgorzata M. Szczęśniak, Evan Trivedi, John F. Trant, Ngong Kodiah Beyeh Apr 2022

Naphthalene-Functionalized Resorcinarene As Selective, Fluorescent Self-Quenching Sensor For Kynurenic Acid†, Anna Karle, Kwaku Twum, Noorhan Sabbagh, Alise Haddad, S. Maryamdokht Taimoory, Małgorzata M. Szczęśniak, Evan Trivedi, John F. Trant, Ngong Kodiah Beyeh

Chemistry and Biochemistry Publications

Kynurenic acid is a by-product of tryptophan metabolism in humans, with abnormal levels indicative of disease. There is a need for water-soluble receptors that selectively bind kynurenic acid, allowing for detection and quantification. We report here the high-affinity binding of kynurenic acid in aqueous media to a resorcinarene salt receptor decorated with four flexible naphthalene groups at the upper rim. Experimental results from 1H NMR, isothermal titration calorimetry, and electronic absorption and fluorescence spectroscopies all support high-affinity binding and selectivity for kynurenic acid over tryptophan. The measured binding constant (K = 1.46 ± 0.21 × 105 M−1) is one …


Effect Of Mono-Vacant Defects On The Adsorption Properties Of Deep Eutectic Solvents Onto Hexagonal Boron-Nitride Nanoflakes, Mehdi Shakourian-Fard, S. Maryamdokht Taimoory, Hamid Reza Ghenaatian, Ganesh Kamath, John F. Trant Mar 2022

Effect Of Mono-Vacant Defects On The Adsorption Properties Of Deep Eutectic Solvents Onto Hexagonal Boron-Nitride Nanoflakes, Mehdi Shakourian-Fard, S. Maryamdokht Taimoory, Hamid Reza Ghenaatian, Ganesh Kamath, John F. Trant

Chemistry and Biochemistry Publications

Hexagonal boron nitride is a promising material for a variety of electronic, optical, and material science applications. Both the synthesis of the material through exfoliation, and its various applications almost inevitably require its solvation. Deep eutectic solvents (DES) are extremely useful solvents for these types of applications due to their non-volatility, inflammability, biocompatibility, and reasonable cost. There are many different deep eutectic solvents available, and their suitability for any given application is particularly dependent on the specific of their structure. DES have been examined computationally for use with boron nitride, but these calculations use idealized, perfect boron nitride sheets instead …


Flexible And Printed Electronics: A Transition In Leadership - Reflecting On Our Successes And Looking Forward To The Future, Tricia Breen Carmichael, Ronald Österbacka Mar 2022

Flexible And Printed Electronics: A Transition In Leadership - Reflecting On Our Successes And Looking Forward To The Future, Tricia Breen Carmichael, Ronald Österbacka

Chemistry and Biochemistry Publications

No abstract provided.


Giving Preparative Thin-Layer Chromatography Some Tender ­Loving Care, John J. Hayward, Lavleen Mader, John F. Trant Feb 2022

Giving Preparative Thin-Layer Chromatography Some Tender ­Loving Care, John J. Hayward, Lavleen Mader, John F. Trant

Chemistry and Biochemistry Publications

Preparative thin-layer chromatography (prepTLC) is a commonly used method of purification suitable for small-scale reactions. However, descriptions of the preferred methodology to load, run, and recover samples from prepTLC are non-standard and varied, making it part of the ‘hidden curriculum’ of laboratory techniques. In this article we report on the simple, cost-effective methods we use to load and collect samples from a plate, which enhance the convenience, speed, and precision of this technique.


Fabrication And Characterization Of Autonomously Self-Healable And Stretchable Soft Microfluidics, Hualong Wang, Susanna Vu, Julia Pignanelli, Tamer Abdel Fatah, John F. Trant, Sara Mahshid, Simon Rondeau-Gagné, Mohammed Jalal Ahamed Feb 2022

Fabrication And Characterization Of Autonomously Self-Healable And Stretchable Soft Microfluidics, Hualong Wang, Susanna Vu, Julia Pignanelli, Tamer Abdel Fatah, John F. Trant, Sara Mahshid, Simon Rondeau-Gagné, Mohammed Jalal Ahamed

Chemistry and Biochemistry Publications

In this paper, a novel self-healable and stretchable microfluidics system for next generation wearable lab-on-a-chip is presented. An imine-based precursor with various metal sources (Co(II), Fe(II), and Zn(II)) is used for the development of an intrinsically autonomous self-healing microfluidic device. Microfluidics fabrication is performed on the self-healing substrate layer using a mold transfer method. The mechanical properties of the resulting layer are evaluated using tensile strain pull testing. Microfluidic characteristics including fluid flow, wettability, leak, and fluorescence compatibility are investigated to understand its performance in classical microfluidic applications. The new microfluidic devices are also characterized using scanning-electron microscopy to evaluate …


Identification Of Alternative Protein Targets Of Glutamate-Ureido-Lysine Associated With Psma Tracer Uptake In Prostate Cancer Cells, Martin K. Bakht, John J. Hayward, Farsheed Shahbazi-Raz, Magdalena Skubal, Ryo Tamura, Keith F. Stringer, Daniel Meister, Varadha Balaji Venkadakrishnan, Hui Xue, Adam Pillon, Mathew Stover, Adam Tronchin, Bre Anne Fifield, Lavleen Mader, Sheng Yu Ku, Gi Jeong Cheon, Keon Wook Kang, Yuzhuo Wang, Xuesen Dong, Himisha Beltran, Jan Grimm, Lis A. Porter, John F. Trant Jan 2022

Identification Of Alternative Protein Targets Of Glutamate-Ureido-Lysine Associated With Psma Tracer Uptake In Prostate Cancer Cells, Martin K. Bakht, John J. Hayward, Farsheed Shahbazi-Raz, Magdalena Skubal, Ryo Tamura, Keith F. Stringer, Daniel Meister, Varadha Balaji Venkadakrishnan, Hui Xue, Adam Pillon, Mathew Stover, Adam Tronchin, Bre Anne Fifield, Lavleen Mader, Sheng Yu Ku, Gi Jeong Cheon, Keon Wook Kang, Yuzhuo Wang, Xuesen Dong, Himisha Beltran, Jan Grimm, Lis A. Porter, John F. Trant

Chemistry and Biochemistry Publications

Prostate-specific membrane antigen (PSMA) is highly overexpressed in most prostate cancers and is clinically visualized using PSMA-specific probes incorporating glutamate-ureido-lysine (GUL). PSMA is effectively absent from certain high-mortality, treatment-resistant subsets of prostate cancers, such as neuroendocrine prostate cancer (NEPC); however, GUL-based PSMA tracers are still reported to have the potential to identify NEPC metastatic tumors. These probes may bind unknown proteins associated with PSMA-suppressed cancers. We have identified the up-regulation of PSMA-like aminopeptidase NAALADaseL and the metabotropic glutamate receptors (mGluRs) in PSMA-suppressed prostate cancers and find that their expression levels inversely correlate with PSMA expression and are associated with GUL-based …


Identifying Membrane Lateral Organization By Contrast-Matched Small Angle Neutron Scattering, Mitchell Dipasquale, Michael H.L. Nguyen, Stuart R. Castillo, Frederick A. Heberle, Drew Marquardt Jan 2022

Identifying Membrane Lateral Organization By Contrast-Matched Small Angle Neutron Scattering, Mitchell Dipasquale, Michael H.L. Nguyen, Stuart R. Castillo, Frederick A. Heberle, Drew Marquardt

Chemistry and Biochemistry Publications

Lipid domains in model membranes are routinely studied to provide insight into the physical interactions that drive raft formation in cellular membranes. Using small angle neutron scattering, contrast-matching techniques enable the detection of lipid domains ranging from tens to hundreds of nanometers which are not accessible to other techniques without the use of extrinsic probes. Here, we describe a probe-free experimental approach and model-free analysis to identify lipid domains in freely floating vesicles of ternary phase separating lipid mixtures.


Influence Of Ceramide On Lipid Domain Stability Studied With Small-Angle Neutron Scattering: The Role Of Acyl Chain Length And Unsaturation, Mitchell Dipasquale, Tye G. Deering, Dhimant Desai, Arun K. Sharma, Shantu Amin, Todd E. Fox, Mark Kester, John Katsaras, Drew Marquardt, Frederick A. Heberle Jan 2022

Influence Of Ceramide On Lipid Domain Stability Studied With Small-Angle Neutron Scattering: The Role Of Acyl Chain Length And Unsaturation, Mitchell Dipasquale, Tye G. Deering, Dhimant Desai, Arun K. Sharma, Shantu Amin, Todd E. Fox, Mark Kester, John Katsaras, Drew Marquardt, Frederick A. Heberle

Chemistry and Biochemistry Publications

Ceramides and diacylglycerols are groups of lipids capable of nucleating and stabilizing ordered lipid domains, structures that have been implicated in a range of biological processes. Previous studies have used fluorescence reporter molecules to explore the influence of ceramide acyl chain structure on sphingolipid-rich ordered phases. Here, we use small-angle neutron scattering (SANS) to examine the ability of ceramides and diacylglycerols to promote lipid domain formation in the well-characterized domain- forming mixture DPPC/DOPC/cholesterol. SANS is a powerful, probe-free technique for interrogating membrane heterogeneity, as it is differentially sensitive to hydrogen's stable isotopes protium and deuterium. Specifcally, neutron contrast is generated …


Sharing The Salt Bowl: Counterion Identity Drives N-Alkyl Resorcinarene Affinity For Pyrophosphate In Water, Kwaku Twum, Seyed Iraj Sadraei, Jordan Feder, S. Maryamdokht Taimoory, Kari Rissanen, John F. Trant, Ngong Kodiah Beyeh Dec 2021

Sharing The Salt Bowl: Counterion Identity Drives N-Alkyl Resorcinarene Affinity For Pyrophosphate In Water, Kwaku Twum, Seyed Iraj Sadraei, Jordan Feder, S. Maryamdokht Taimoory, Kari Rissanen, John F. Trant, Ngong Kodiah Beyeh

Chemistry and Biochemistry Publications

N-Alkyl ammonium resorcinarene chloride receptors, NARX4, have been shown to act as high-sensitivity detectors of pyrophosphate (PPi), a biomarker of disease, in aqueous media through the chloride-to-PPi exchange [NAR(Cl)4 to NARPPi]. The nature of the anion of the macrocyclic NARX4 (X = Cl−, Br−, triflate OTf−) receptor greatly influences the PPi-affinity in aqueous media. The binding affinity for [NAR (Cl)4] is 3.61 × 105 M−1, while the NAR (Br)4 and NAR (OTf)4 show stronger binding of 5.30 × 105 M−1, and 6.10 × 105 M−1, respectively. The effects of upper rim ammonium cation, –N+H2R substituents (R = 3-hydroxypropyl, cyclohexyl, …


Reaction Of Alkynyl- And Alkenyltrifluoroborates With Propargyldicobalt Cations: Alkynylation, Alkenylation, And Cyclopropanation Product Pathways, Brent St Onge, S. Maryamdokht Taimoory, Jeffrey Battersby, John F. Trant, James R. Green Dec 2021

Reaction Of Alkynyl- And Alkenyltrifluoroborates With Propargyldicobalt Cations: Alkynylation, Alkenylation, And Cyclopropanation Product Pathways, Brent St Onge, S. Maryamdokht Taimoory, Jeffrey Battersby, John F. Trant, James R. Green

Chemistry and Biochemistry Publications

The Lewis acid-mediated Nicholas reactions of propargyl acetate–Co2(CO)6 complexes with a series of potassium alkynyltrifluoroborates and potassium alkenyltrifluoroborates are described. Alkynyltrifluoroborates directly alkynylate the intermediate propargyldicobalt cations. In contrast, alkenyltrifluoroborates proceed through one of the three modes of dominant reactivity: C-2-substituted alkenyltrifluorobrates directly alkenylate, predominantly with the retention of stereochemistry. C-1-substituted alkenyltrifluoroborates alkenylate at C-2. Potassium vinyltrifluoroborate incorporates a cyclopropane at the site propargyl to alkynedicobalt. Computational analysis of these systems explains the differential modes of reactivity of alkenyltrifluoroborates and outlines the probable mechanisms for the formation of each product.


Protocol For Fabricating Electroless Nickel Immersion Gold Strain Sensors On Nitrile Butadiene Rubber Gloves For Wearable Electronics, Sara S. Mechael, Yunyun Wu, Yiting Chen, Tricia Breen Carmichael Dec 2021

Protocol For Fabricating Electroless Nickel Immersion Gold Strain Sensors On Nitrile Butadiene Rubber Gloves For Wearable Electronics, Sara S. Mechael, Yunyun Wu, Yiting Chen, Tricia Breen Carmichael

Chemistry and Biochemistry Publications

This protocol describes the fabrication of patterned conductive gold films on nitrile butadiene rubber (NBR) gloves for wearable strain sensors using electroless nickel immersion gold (ENIG) plating, a solution-based metallization technique. The resulting NBR/ENIG films are strain sensitive; resistance measurements of a patterned sensing array can be used to map human hand motions. This protocol also describes challenges related to the ENIG process and troubleshooting steps to achieve conformal gold films for strain sensing over a large working range. For complete details on the use and execution of this protocol, please refer to Mechael et al. (2021).


Synergistic Broad-Spectrum Antibacterial Activity Of Hypoxis Hemerocallidea-Derived Silver Nanoparticles And Streptomycin Against Respiratory Pathobionts, Oluwole S. Aremu, T. Qwebani-Ogunleye, Lebogang Katata-Seru, Zimbili Mkhize, John F. Trant Dec 2021

Synergistic Broad-Spectrum Antibacterial Activity Of Hypoxis Hemerocallidea-Derived Silver Nanoparticles And Streptomycin Against Respiratory Pathobionts, Oluwole S. Aremu, T. Qwebani-Ogunleye, Lebogang Katata-Seru, Zimbili Mkhize, John F. Trant

Chemistry and Biochemistry Publications

Respiratory tract infections arise due to the introduction of microbes into the airway, disrupting the normal, healthy, complex interdependent microbiome. The selective disruption of this community can be either beneficial or dangerous. Nanoparticles are a potential tool for modifying this population. Coated silver nanoparticles (AgNPs) were synthesized using ethanolic extracts of Hypoxis hemerocallidea (EEHH), a Southern African plant used extensively in traditional medicine and the source of many bioactive secondary metabolites. The room temperature reaction between silver nitrate and EEHH forms largely spherical AgNPs with an average diameter of 6–20 nm. These nanoparticles show similar levels of antibacterial activity as …


New Isolate From Salvinia Molesta With Antioxidant And Urease Inhibitory Activity, Nadra Naheed, Saima Maher, Farooq Saleem, Ajmal Khan, Abdul Wadood, Saima Rasheed, M. Iqbal Choudhary, Matheus Froeyen, Iskandar Abdullah, Muhammad Usman Mirza, John F. Trant, Sarfraz Ahmad Dec 2021

New Isolate From Salvinia Molesta With Antioxidant And Urease Inhibitory Activity, Nadra Naheed, Saima Maher, Farooq Saleem, Ajmal Khan, Abdul Wadood, Saima Rasheed, M. Iqbal Choudhary, Matheus Froeyen, Iskandar Abdullah, Muhammad Usman Mirza, John F. Trant, Sarfraz Ahmad

Chemistry and Biochemistry Publications

Urease plays a significant role in the pathogenesis of urolithiasis pyelonephritis, urinary catheter encrustation, hepatic coma, hepatic encephalopathy, and peptic acid duodenal ulcers. Salvinia molesta was explored to identify new bioactive compounds with particular emphasis on urease inhibitors. The aqueous methanol extract was fractionated using solvents of increasing polarity. A series of column chromatography and later HPLC were performed on butanol extract. The structures of the resulting pure compounds were resolved using NMR (1D and 2D), infrared, and mass spectroscopy. The novel isolate was evaluated for antioxidant activity (using DPPH, superoxide anion radical scavenging, oxidative burst, and Fe+2 chelation assays), …


From Fat To Bilayers: Understanding Where And How Vitamin E Works, Jeffrey Atkinson, Drew Marquardt, Mitchell Dipasquale, Thad Harroun Nov 2021

From Fat To Bilayers: Understanding Where And How Vitamin E Works, Jeffrey Atkinson, Drew Marquardt, Mitchell Dipasquale, Thad Harroun

Chemistry and Biochemistry Publications

Vitamin E was one of the last fat-soluble vitamins to be discovered. We provide here an historical review of the discovery and the increasingly more detailed understanding of the role of α-tocopherol both as an antioxidant and as a structural component of phospholipid bilayer membranes. Despite the detailed descriptions now available of the orientation, location, and dynamics of α-tocopherol in lipid bilayers, there are still gaps in our knowledge of the effect of α-tocopherol and its potential receptors than control gene transcription.


Efficient And Reproducible Synthesis Of An Fmoc-Protected Tn Antigen, Sabrina M. Piazza, Michael R. Reynolds, Jonathan Chiaramonte, Peihan Xu, Fabiola A. Chapa-Villarreal, John F. Trant Nov 2021

Efficient And Reproducible Synthesis Of An Fmoc-Protected Tn Antigen, Sabrina M. Piazza, Michael R. Reynolds, Jonathan Chiaramonte, Peihan Xu, Fabiola A. Chapa-Villarreal, John F. Trant

Chemistry and Biochemistry Publications

This concise total synthesis of the Thomsen-Nouveau (Tn) glycoconjugate was accomplished using a palladium-catalyzed coupling between the glycosyl donor and Fmoc-protected serine acceptor. This is, to the best of our knowledge, the shortest synthesis reported from galactose for preparing this essential building block for large-scale solid phase peptide synthesis.


A Calorimetric, Volumetric And Combined Sans And Saxs Study Of Hybrid Siloxane Phosphocholine Bilayers, Mark B. Frampton, Doruntina Yakoub, John Katsaras, Paul M. Zelisko, Drew Marquardt Nov 2021

A Calorimetric, Volumetric And Combined Sans And Saxs Study Of Hybrid Siloxane Phosphocholine Bilayers, Mark B. Frampton, Doruntina Yakoub, John Katsaras, Paul M. Zelisko, Drew Marquardt

Chemistry and Biochemistry Publications

Siloxanes are molecules used extensively in commercial, industrial, and biomedical applications. The inclusion of short siloxane chains into phospholipids results in interesting physical properties, including the ability to form low polydispersity unilamellar vesicles. As such, hybrid siloxane phosphocholines (SiPCs) have been examined as a potential platform for the delivery of therapeutic agents. Using small angle X-ray and neutron scattering, vibrating tube densitometry, and differential scanning calorimetry, we studied four hybrid SiPCs bilayers. Lipid volume measurements for the different SiPCs compared well with those previously determined for polyunsaturated PCs. Furthermore, the different SiPC's membrane thicknesses increased monotonically with temperature and, for …


Accident Experiences And Reporting Practices In Canadian Chemistry And Biochemistry Labs: A Pilot Investigation, Dana Ménard, John F. Trant Oct 2021

Accident Experiences And Reporting Practices In Canadian Chemistry And Biochemistry Labs: A Pilot Investigation, Dana Ménard, John F. Trant

Chemistry and Biochemistry Publications

Accidents in chemistry and biochemistry laboratories are a regular occurrence and have been associated with injuries, property damage, and deaths. However, despite a high prevalence rate of accident involvement reported in previous investigations of academic lab personnel (approximately 30%), little is known about the context in which academic lab accidents occur. Previous findings also suggest a high degree of accident underreporting (25–40%), but again, little is known about this phenomenon. Pilot data was gathered from a convenience sample of 104 students and postdoctoral fellows in chemistry-related fields through an online survey. Results showed a high level of accident involvement (56.7%); …


Fabrication Of An Autonomously Self-Healing Flexible Thin-Film Capacitor By Slot-Die Coating, Susanna Vu, Gnanesh Nagesh, Nastaran Yousefi, John F. Trant, David S.K. Ting, M. Jalal Ahamed, Simon Rondeau-Gagné Oct 2021

Fabrication Of An Autonomously Self-Healing Flexible Thin-Film Capacitor By Slot-Die Coating, Susanna Vu, Gnanesh Nagesh, Nastaran Yousefi, John F. Trant, David S.K. Ting, M. Jalal Ahamed, Simon Rondeau-Gagné

Chemistry and Biochemistry Publications

Flexible pressure sensors with self-healing abilities for wearable electronics are being developed, but generally either lack autonomous self-healing properties or require sophisticated material processing methods. To address this challenge, we developed flexible, low-cost and autonomously self-healing capacitive sensors using a crosslinked poly(dimethylsiloxane) through metal-ligand interactions processed into thin films via slot-die coating. These films have excellent self-healing properties, approximately 1.34 × 105 μm3 per hour at room temperature and 2.87 × 105 μm3 per hour at body temperature (37 °C). Similarly, no significant change in capacitance under bending strain was observed on these flexible thin-films when assembled on poly(ethyleneterephthalate) (PET) …


Synthesis, Characterization And Stress-Testing Of A Robust Quillaja Saponin Stabilized Oil-In-Water Phytocannabinoid Nanoemulsion, Abhinandan Banerjee, Justin Binder, Rayan Salama, John F. Trant Sep 2021

Synthesis, Characterization And Stress-Testing Of A Robust Quillaja Saponin Stabilized Oil-In-Water Phytocannabinoid Nanoemulsion, Abhinandan Banerjee, Justin Binder, Rayan Salama, John F. Trant

Chemistry and Biochemistry Publications

Background

This study describes the design, optimization, and stress-testing of a novel phytocannabinoid nanoemulsion generated using high-pressure homogenization.QNaturale®" role="presentation">QNaturale®, a plant-derived commercial emulsifier containing quillaja saponin, was used to stabilize the lipid phase droplets in water. Stress-testing was performed on this nanoemulsion in order to evaluate its chemical and colloidal stability under the influence of different environmental factors, encompassing both physical and chemical stressors.

Methods

Extensive optimization studies were conducted to arrive at an ideal nanoemulsion formulation. A coarse emulsion containing 16.6 wt% CBD-enriched cannabis distillate and 83.4 wt% carrier (soybean) oil dispersed in 10 wt%QNaturale®" role="presentation">QNaturale®

(1.5 …