Article
Materials Science, Multidisciplinary
Ameen Uddin Ammar, Ipek Deniz Yildirim, Mohamad Hasan Aleinawi, Merve Buldu-Akturk, Nur Selin Turhan, Shankari Nadupalli, Arpad Mihai Rostas, Emre Erdem
Summary: The doping of Mn, Fe, and Cu ions into ZnO nanocrystals adds magnetic phenomena to their semiconducting property. However, there is a lack of research on the local lattice structure, spin-exchange phenomena, and interaction between defects and doped metal ions in TM ion-doped ZnO. This study uses multi-frequency (EPR) techniques to investigate ZnO:TM, revealing the localization of the dopant ion, site symmetry, and the formation of intrinsic-extrinsic defect complexes. The incorporation of TM ions modifies the intrinsic defect structure of ZnO nanocrystals, with the appearance of peculiar spin-exchange phenomena from intrinsic-extrinsic defect complexes, and charge selective substitutions in the matrix are observed for Cu2+ compared to Mn2+ and Fe3+.
MATERIALS RESEARCH BULLETIN
(2023)
Article
Chemistry, Analytical
Hideo Utsumi, Toshiki Masumizu, Ryoma Kobayashi, Tomoko Tahira, Fuminori Hyodo, Tatsuya Shimizu, Tatsuya Naganuma, Kazunori Anzai
Summary: Free radicals are key substances in organisms but can also cause oxidative diseases. Dynamic nuclear polarization- magnetic resonance imaging is a noninvasive imaging method that can be used for in vivo free radical imaging.
ANALYTICAL CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Toshinobu Nakajo, Jun Kumagai, Shinpei Kusaka, Akihiro Hori, Yuh Hijikata, Jenny Pirillo, Yunsheng Ma, Ryotaro Matsuda
Summary: Triplet carbenes (TCs) are highly reactive species with unique electronic states, making it challenging to balance reactivity and stability. By confining TCs in the nanospace of a metal-organic framework (MOF), it is possible to enhance their thermal stability while maintaining reactivity, allowing for the stabilization of highly reactive species.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Physics, Applied
Jiri Dolezal, Pablo Merino, Martin Svec
Summary: The study introduces an optical method for determining the frequency-dependent magnitude of the transfer function of a high-frequency line integrated with a scanning probe microscope. By determining the energy cutoff of the plasmonic electroluminescence spectrum, the method is effective in linking to the energies of the electrons inelastically tunneling across the junction. The research demonstrates that the method shows good agreement with conventional fully electronic calibration in compensating for radio frequency line and determining the transfer function magnitude in the GHz range.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Yuri E. Kandrashkin, Art van der Est
Summary: This paper presents a model that describes the effect of incoherent state hopping on spin-polarized transient EPR signals. It shows that the size of the spin state space can be reduced by half and the system dynamics result in a redistribution of population among its eigenstates. Analytical expressions are derived for population redistribution rates and line shapes, and the calculated EPR signals are in good agreement with numerical solutions. The model is then used to investigate the influence of exciton hopping on triplet state transient EPR spectra.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
A. Solodovnyk, O. Laguta, A. Prokhorov, M. Segantini, B. Naydenov, P. Neugebauer, S. Greulich-Weber, E. Kalabukhova, D. Savchenko
Summary: This study investigates nitrogen-doped 15R silicon carbide monocrystals using multifrequency electron paramagnetic resonance (EPR) and electrically detected magnetic resonance (EDMR) spectroscopic methods. The results show the existence of an intensive S line related to nitrogen doping in 15R SiC. The analysis indicates different interaction processes occurring at different temperature ranges. The results from MW conductivity measurements agree with EPR and EDMR data, suggesting that the temperature variation is mainly controlled by electron hopping processes.
Article
Chemistry, Inorganic & Nuclear
Anthony J. Campanella, Manh-Thuong Nguyen, Jun Zhang, Thacien Ngendahimana, William E. Antholine, Gareth R. Eaton, Sandra S. Eaton, Vassiliki-Alexandra Glezakou, Joseph M. Zadrozny
Summary: This work investigates how variations in ligand structures affect the EPR spectroscopic properties of five Cr(III) complexes, indicating that the spectral broadening is correlated to rigidity in the inner coordination sphere and reflected in ligand-dependent distribution of Cr-N bond distances.
DALTON TRANSACTIONS
(2021)
Article
Materials Science, Multidisciplinary
V. V. Ogloblichev, S. V. Verkhovskii, A. Mirmelstein, Y. Piskunov, A. Y. Germov, A. M. Potapov, A. F. Gubkin, A. Andreev
Summary: The study investigated the spin susceptibility and low-frequency dynamics of uranium 5f electrons using nuclear magnetic resonance (NMR) on uranium mononitride (UN) single crystalline and polycrystalline samples in paramagnetic and magnetically ordered phases. The joint analysis of NMR and magnetic susceptibility data allowed to determine the temperature dependence of spin fluctuation energy of the uranium 5f electrons. In the magnetically ordered UN phase, the N-14 NMR spectra consist of several lines that can be explained in terms of the model of type I antiferromagnetic order corresponding to 1k structure in the presence of magnetic domains.
Article
Materials Science, Multidisciplinary
Ushnish Chaudhuri, Debendra Prasad Panda, A. Sundaresan, R. Mahendiran
Summary: The study investigated the frequency-dependent microwave absorption of La2NiMnO6 using two cavity-less methods. The results showed variations in the material's behavior at different frequencies, with resonance fields increasing linearly with frequency. Analysis of the resonance fields supported the presence of Ni2+ cation with strong spin-orbit coupling.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Multidisciplinary Sciences
Patryk Kuleta, Jonathan Lasham, Marcin Sarewicz, Iwona Ekiert, Vivek Sharma, Robert Ekiert, Artur Osyczka
Summary: This study identifies a dual role of hydrogen bonding in regulating the redox potential of heme in cytochrome bc1, which is essential for maintaining proper function of energy-conserving systems. By stabilizing this hydrogen bond, both the redox potential of the heme and its spin state can be influenced, potentially leading to changes in electron transfer rates and interactions with redox partners. These findings suggest a delicate balance between H-bond stability and heme-protein interactions in fine-tuning the redox properties of heme proteins.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Multidisciplinary Sciences
Juvinch R. Vicente, Amanda Durkin, Kristina Shrestha, Mihaela Balu
Summary: Melanin plays a significant role in skin homeostasis and protection. The two-photon excited fluorescence lifetime detection method allows for selective and quantitative measurement of melanin. Previous studies lacked consideration of skin heterogeneity due to limited field of view. In this work, a fast large-area multiphoton exoscope was used to evaluate the 3D distribution of epidermal melanin content, improving measurement reliability.
SCIENTIFIC REPORTS
(2022)
Article
Materials Science, Multidisciplinary
S. A. Rodriguez, S. S. Gomez, J. Fernandez-Rossier, A. Ferron
Summary: Electron-spin resonance carried out with scanning tunneling microscopes (ESR-STM) is a recently developed experimental technique that is attracting enormous interest on account of its potential to carry out single-spin on-surface resonance with subatomic resolution. In this theoretical study, we investigate the role of tip-adatom interactions in order to optimize spin resonance measurements. We provide guidelines for optimizing the tip-sample distance to cancel the effective magnetic field created by the tip on the surface spin, for reducing the voltage dependence of the surface-spin resonance frequency, and for inferring the detuning angle between the applied field and the tip magnetization.
Article
Physics, Applied
T. D. Gustafson, N. C. Giles, B. C. Holloway, C. A. Lenyk, J. Jesenovec, J. S. McCloy, M. D. McCluskey, L. E. Halliburton
Summary: In this study, electron paramagnetic resonance (EPR) and optical absorption were used to characterize Cu2+ and Cu3+ ions in Cu-doped beta-Ga2O3. Different EPR spectra and optical absorption bands were observed for Cu2+ and Cu3+ ions. The results showed that Cu2+(A) ions occupy defect-free octahedral Ga sites, while Cu2+(B) ions have adjacent defects, possibly OH- ions, oxygen vacancies, or H- ions trapped within oxygen vacancies. Additionally, exposure of the crystals to 275 nm light at room temperature produced Cu3+ ions and reduced the number of Cu2+(A) and Cu2+(B) ions. Thermal annealing studies showed that Cu3+ ions decay, and Cu2+ ions recover.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Santina S. Cruz, Vadim Tanygin, Benjamin J. Lear
Summary: Using electron spin resonance spectroscopy, it has been demonstrated that morphological asymmetries in small spheroidal metallic nanoparticles significantly affect the electronic behavior of states near the metal's Fermi energy. The study found that morphological effects were more important than size distributions in explaining the asymmetry in electronic behavior, and this was consistent across various particles made from different metals. Additionally, the study also showed that morphological changes can tune the electronic properties of even small particles, as evidenced by the modeling used to explain asymmetries in both electron spin resonance spectra and plasmon spectra.
Article
Physics, Multidisciplinary
K. Lamonova, S. Orel, Yu. Pashkevich, B. Bekirov, M. Hidulianov, I. Ivanchenko, N. Popenko, N. Kovalenko, A. Prokhorov, Yu. Hizhnyi, S. Nedilko, N. Klyui
Summary: In this study, we collected the EPR spectra of Fe ions in zinc selenide single crystals and investigated the effects of temperature on charge transfer and EPR spectrum formation mechanism. A theoretical model of EPR spectrum formation was established using complex theoretical methods, and the impact of structural defects during the doping process on the EPR spectrum was analyzed.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Biochemistry & Molecular Biology
Osha Roopnarine, David D. Thomas
Summary: The study found that ten actin-binding compounds affect the interaction between cardiac myosin subfragment 1 (S1) and pyrene-labeled F-actin (PFA), increasing ATP affinity for actin-bound myosin and slowing the transition of actin-myosin interaction in the early ATPase cycle. This work elucidates the mechanisms of action for these compounds, providing valuable insights for potential treatments of hypercontractile forms of cardiomyopathy and future drug discovery efforts for heart failure.
JOURNAL OF BIOLOGICAL CHEMISTRY
(2021)
Article
Biochemistry & Molecular Biology
Ang Li, Samantha L. Yuen, Daniel R. Stroik, Evan Kleinboehl, Razvan L. Cornea, David D. Thomas
Summary: The study demonstrates that DWORF enhances SERCA2a function by competing with PLB for binding, potentially offering a novel therapeutic approach for heart failure.
JOURNAL OF BIOLOGICAL CHEMISTRY
(2021)
Article
Biochemistry & Molecular Biology
Abir Majumdar, David J. Burban, Joseph M. Muretta, Andrew R. Thompson, Tiffany A. Engel, Damien M. Rasmussen, Manu V. Subrahmanian, Gianluigi Veglia, David D. Thomas, Nicholas M. Levinson
Summary: CDKs are master regulators of the eukaryotic cell cycle, requiring regulatory phosphorylation and cyclin binding for activation. The study explores the activation process of Cdk2 and its allosteric coupling with different regulators, revealing differences between Cdk2 and Cdk4 in allosteric wiring and substrate specificity.
NATURE CHEMICAL BIOLOGY
(2021)
Article
Biology
Cristina Olivieri, Caitlin Walker, Adak Karamafrooz, Yingjie Wang, V. S. Manu, Fernando Porcelli, Donald K. Blumenthal, David D. Thomas, David A. Bernlohr, Simon M. Sandford, Susan S. Taylor, Gianluigi Veglia
Summary: The fusion of the dynamic J-domain to PKA-C disrupts the internal allosteric network, causing attenuation of nucleotide/PKI binding cooperativity. This reduced allosteric cooperativity alters specific recognitions and interactions between substrates and regulatory partners, contributing to dysregulation exhibited by PKA-C-DNAJB1.
COMMUNICATIONS BIOLOGY
(2021)
Article
Biology
Daniel K. Weber, U. Venkateswara Reddy, Songlin Wang, Erik K. Larsen, Tata Gopinath, Martin B. Gustavsson, Razvan L. Cornea, David D. Thomas, Alfonso De Simone, Gianluigi Veglia
Summary: Phospholamban (PLN) regulates cardiac Ca2+ transport response by phosphorylation or increased Ca2+ concentration, disrupting inhibitory contacts on the SERCA binding interface and enhancing Ca2+ transport. This study sheds light on the signal transduction mechanism operated by posttranslationally modified bitopic membrane proteins, addressing longstanding questions about SERCA regulation.
Correction
Biology
Cristina Olivieri, Caitlin Walker, Adak Karamafrooz, Yingjie Wang, V. S. Manu, Fernando Porcelli, Donald K. Blumenthal, David D. Thomas, David A. Bernlohr, Sanford M. Simon, Susan S. Taylor, Gianluigi Veglia
COMMUNICATIONS BIOLOGY
(2021)
Article
Biochemistry & Molecular Biology
Thomas A. Bunch, Piyali Guhathakurta, Victoria C. Lepak, Andrew R. Thompson, Rhye-Samuel Kanassatega, Anna Wilson, David D. Thomas, Brett A. Colson
Summary: This study identified small-molecule inhibitors that affect the binding between cMyBP-C and actin, providing potential targets for heart failure drugs that mimic phosphorylation or disrupt interactions with actin/myosin. The fluorescence lifetime assay allowed for the detection of pharmacologically active compounds that interfere with cMyBP-C-actin binding. This validated high-throughput screen focused on cMyBP-C, a regulator of cardiac muscle contractility and a key factor in heart failure, for the first time.
JOURNAL OF BIOLOGICAL CHEMISTRY
(2021)
Article
Biochemistry & Molecular Biology
Sami Chu, Joseph M. Muretta, David D. Thomas
Summary: The study aimed to test whether the IHM structure is the structural basis for the SRX state, and the results indicated that the IHM structure is sufficient but not necessary to produce the SRX kinetic state.
JOURNAL OF BIOLOGICAL CHEMISTRY
(2021)
Article
Biochemistry & Molecular Biology
Mark D. Rustad, Osha Roopnarine, Razvan L. Cornea, David D. Thomas
Summary: Insufficient activity of SERCA, the integral transmembrane Ca2+ pump, contributes significantly to heart failure, a leading cause of death worldwide. The novel DWORF micropeptide has been identified as a muscle-specific SERCA effector that can reverse the inhibitory effects of PLB and activate SERCA independently. However, the structural basis for these functions has not yet been determined.
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
(2023)
Article
Biochemistry & Molecular Biology
Philip A. A. Bidwell, Samantha L. L. Yuen, Ji Li, Kaja Berg, Robyn T. T. Rebbeck, Courtney C. C. Aldrich, Osha Roopnarine, Razvan L. L. Cornea, David D. D. Thomas
Summary: The sarco/endoplasmic reticulum Ca-ATPase (SERCA) is a critical ion pump for muscle function, and increasing its activity could alleviate muscle dysfunction. Through high-throughput screening, several compounds were discovered that can activate SERCA and improve calcium uptake in both cardiac and skeletal muscles.
Article
Biochemistry & Molecular Biology
Bengt Svensson, Florentin R. Nitu, Robyn T. Rebbeck, Lindsey M. Mcgurran, Tetsuro Oda, David D. Thomas, Donald M. Bers, Razvan L. Cornea
Summary: Current studies have shown that Ca2+ leakage from cardiomyocyte sarcoplasmic reticulum through hyperactive resting cardiac ryanodine receptor channels (RyR2) has a pro-arrhythmic effect. An exogenous peptide (DPc10) binding promotes leaky RyR2 in cardiomyocytes and reports on the endogenous state. Conversely, binding of calmodulin (CaM) inhibits RyR2 leak and low CaM affinity is indicative of leaky RyR2. These findings have led to the development of a FRET biosensor for drug discovery targeting RyR2.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Biochemistry & Molecular Biology
Elisa Bovo, Robyn T. Rebbeck, Osha Roopnarine, David D. Thomas, Razvan L. Cornea, Aleksey Zima
Summary: This study reveals that Compound 6 exhibits promising characteristics that can improve intracellular Ca2+ dynamics by selectively enhancing SERCA2a Ca2+ uptake.
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
(2023)
Article
Veterinary Sciences
Joseph M. Autry, Bengt Svensson, Samuel F. Carlson, Zhenhui Chen, Razvan L. Cornea, David D. Thomas, Stephanie J. Valberg
Summary: The enzymatic activity of SERCA from horse muscle was analyzed, and it was found that horse SR vesicles have a higher Ca2+ transport rate and increased luminal Ca2+ stores compared to rabbit SR vesicles. This may be due to a reduced SLN inhibition of SERCA and abundant expression of CASQ in horse myofibers.
VETERINARY SCIENCES
(2021)
Article
Biochemical Research Methods
Adak Karamafrooz, Jack Brennan, David D. Thomas, Laurie L. Parker
Summary: The DNAJB1-PRKACA fusion is a signature genetic event of FL-HCC, potentially upregulating oncogenic pathways through redirecting substrate recognition. By integrating cell-based and in vitro phosphoproteomics, substrates directly targeted by PKA and J-PKA(ca) were identified, with inhibitors showing differential effects on substrates in the presence of the fusion protein.
JOURNAL OF PROTEOME RESEARCH
(2021)
Article
Biochemistry & Molecular Biology
Robyn T. Rebbeck, Anna K. Andrick, Sarah A. Denha, Bengt Svensson, Piyali Guhathakurta, David D. Thomas, Thomas S. Hays, Adam W. Avery
Summary: This study established a high-throughput screening method for discovering potential disrupters of the interaction between mutant beta-III-spectrin ABD and actin in live cells, showing its effectiveness.
JOURNAL OF BIOLOGICAL CHEMISTRY
(2021)