Relativistic restricted active space (RAS) second-order multireference perturbation theory (MRPT2) methods, incorporating spin-orbit (SO) coupling perturbatively via state interaction (SO-MRPT2/RASSCF), were used to reproduce the absorption spectra of parent metalloporphyrins containing the Mg, Zn, Co, Ni, Cu, or FeCl ions in the 12,500-40,000 cm region. Particular attention was paid to the interaction between the porphyrin ring and the metal 3 electrons in states of different multiplicities (we used metal 3 and double -shell or 3' orbitals). For this class of compounds, the -electron valence state perturbation theory (NEVPT2) method is superior to the complete active space perturbation theory (CASPT2) and successfully reproduces the energies of all four characteristic transitions (, , , and ) of closed-shell metalloporphyrins.
View Article and Find Full Text PDFUnlabelled: The period of the year from spring to fall, when clocks in most parts of the United States are set one hour ahead of standard time, is called daylight saving time, and its beginning and ending dates and times are set by federal law. The human biological clock is regulated by the timing of light and darkness, which then dictates sleep and wake rhythms. In daily life, the timing of exposure to light is generally linked to the social clock.
View Article and Find Full Text PDFAs the world grapples with global warming, it becomes imperative to carefully examine the sustainable energy technology choices. Solar is the fastest growing clean energy source but today it contributes little to the electricity generated, so future installations will dwarf the existing installed base. There is a factor of 2-4 decrease in the energy payback time from the dominant crystalline silicon technology to thin film technologies.
View Article and Find Full Text PDFBackground: Coronavirus disease 2019 (CoVID-19), primarily thought of as a respiratory system disease is actually a multi-system disease with immunological implications. CNS involvement in COVID has been explained in recent literature mainly for stroke, encephalopathy, encephalitis, acute disseminated encephalomyelitis and myelopathy. There are few studies characterizing clinical spectrum of COVID autoimmune encephalitis.
View Article and Find Full Text PDFCorrection for 'Enhanced 5f-δ bonding in [U(CH)]: C K-edge XAS, magnetism, and calculations' by Yusen Qiao , , 2021, , 9562-9565, DOI: 10.1039/D1CC03414F.
View Article and Find Full Text PDFChem Commun (Camb)
September 2021
5f covalency in [U(CH)] was probed with carbon K-edge X-ray absorption spectroscopy (XAS) and electronic structure theory. The results revealed U 5f orbital participation in δ-bonding in both the ground- and core-excited states; additional 5f ϕ-mixing is observed in the core-excited states. Comparisons with U(CH) show greater δ-covalency for [U(CH)].
View Article and Find Full Text PDFPhys Chem Chem Phys
August 2021
Cyclobutadiene (CBD) is the paradigmatic antiaromatic molecule but is known to form highly stable aromatic complexes, e.g. CBD-Fe(CO)3.
View Article and Find Full Text PDFC-term magnetic circular dichroism (MCD) spectroscopy is a powerful method for probing d-d and f-f transitions in paramagnetic metal complexes. However, this technique remains underdeveloped both experimentally and theoretically for studies of U(v) complexes of Oh symmetry, which have been of longstanding interest for probing electronic structure, bonding, and covalency in 5f systems. In this study, C-term NIR MCD of the Laporte forbidden f-f transitions of [UCl6]- and [UF6]- are reported, demonstrating the significant fine structure resolution possible with this technique including for the low energy Γ7 → Γ8 transitions in [UF6]-.
View Article and Find Full Text PDFA 5-year-old male child of consanguineous parentage, without any adverse perinatal history, presented with progressive cognitive regression predominantly in the language and attention domains, for 2 years. He had simultaneous pyramidal and extrapyramidal involvement, frequent generalised tonic-clonic seizures and recurrent respiratory tract infections. Examination was significant for vertical supranuclear gaze palsy, coarse facial features and splenomegaly.
View Article and Find Full Text PDFYuen K, Strang AR, Flynn-Evans EE, et al. Child and teen sleep and pandemic-era school. 2021;17(4):613–615.
View Article and Find Full Text PDFCharcot-Marie-Tooth (CMT) disease is mainly a disease of peripheral nervous system and patients typically present with features of demyelinating neuropathy or axonal neuropathy or both. Rarely patients present with features of central nervous system involvement. Parkinsonism, aphemia and familial epilepsy syndrome have previously come up as case reports in association with CMT type 4 J.
View Article and Find Full Text PDFThe absorption spectra of the octahedral [UX] (X = Cl, Br; = 1, 2) complexes in the near-infrared (NIR) and UV-vis spectral regions were studied theoretically, using a relativistic restricted active space second-order perturbation theory (RASPT2) wavefunction framework, with the spin-orbit (SO) coupling treated by state interaction, in conjunction with Kohn-Sham density functional theory calculations for determining the vibrational normal modes. The electric-dipole-allowed ligand-to-metal charge-transfer (LMCT) and 5f-to-6d transitions, and the electric-dipole-forbidden 5f-to-5f ligand field (LF) transitions, are thereby obtained within the same theoretical framework. For the 5f-to-5f LF transitions, the observed absorption intensity is mostly due to vibronic coupling with low-energy electric-dipole-allowed transitions, but in some cases, the magnetic dipole intensity of the purely electronic transition has comparable intensity to the vibronic transitions.
View Article and Find Full Text PDFMyelin oligodendrocyte glycoprotein antibody (MOG-Ab) is involved in the pathogenesis of central nervous system (CNS) demyelination disorders. We aimed to explore the spectrum of MOG-Ab-associated diseases in eastern India. A single-center, prospective observational study was done over a period of 2 years in a tertiary care hospital of eastern India.
View Article and Find Full Text PDFAnn Indian Acad Neurol
February 2020
Background And Aims: To study the clinical profile of genetically proven Huntington's disease (HD) patients from eastern India.
Methods: This cross sectional study selected patients of HD after genetic confirmation of expanded CAG repeats in Huntingtin () gene. We performed detail clinical evaluation including cognitive and neuropsychological assessment, and imaging of brain.
Relativistic multireference ab initio wave function calculations with the restricted active space second-order perturbation theory (RASPT2) were performed on thorocene and uranocene to determine the actinide N -edge and carbon K-edge X-ray absorption near-edge structure (XANES) intensities and the metal-ligand orbital mixing in the ground state and core-excited states. Calculated spectral intensities show very good agreement with the experiments and therefore allow detailed and unambiguous assignment of the observed spectral features. φ-type covalent bonding or antibonding interactions are observed for thorocene in the core-excited states, though not in the ground state.
View Article and Find Full Text PDFThe cytotoxicity of dopamine on cultured cells of neural origin has been used as a tool to explore the mechanisms of dopaminergic neurodegeneration in Parkinson's disease. In the current study, we have shown that dopamine induces a dose-dependent (10-40 μM) and time-dependent (up to 96 h) loss of cell viability associated with mitochondrial dysfunction and increased intra-cellular accumulation of α-synuclein in cultured SH-SY5Y cells. Dopamine-induced mitochondrial dysfunction and the loss of cell viability under our experimental conditions could be prevented by cyclosporine, a blocker of mitochondrial permeability transition pore, as well as the antioxidant N-acetylcysteine.
View Article and Find Full Text PDFA mononuclear iron(II) complex [Fe(N4Py)(OTf)](OTf)(1), supported by a new pentadentate ligand, bis(6-methylpyridin-2-yl)- N, N-bis((pyridin-2-yl)methyl)methanamine (N4Py), has been isolated and characterized. Introduction of methyl groups in the 6-position of two pyridine rings makes the N4Py a weaker field ligand compared to the parent N4Py ligand. Complex 1 is high-spin in the solid state and converts to [Fe(N4Py)(CHCN)](OTf) (1a) in acetonitrile solution.
View Article and Find Full Text PDFThe aging of brain in the absence of neurodegenerative diseases, usually called non-pathological brain aging or normal cognitive aging, is characterized by an impairment of memory and cognitive functions. The underlying cellular and molecular changes in the aging brain that include oxidative damage, mitochondrial impairment, changes in glucose-energy metabolism and neuroinflammation have been reported widely from animal experiments and human studies. The cognitive deficit of non-pathological brain aging is the resultant of such inter-dependent and reinforcing molecular pathologies which have striking similarities with those operating in Alzheimer's disease which causes progressive, irreversible and a devastating form of dementia and cognitive decline in the elderly people.
View Article and Find Full Text PDFMolecular solar thermal storage (MOST) systems have been largely limited to three classes of molecular motifs: azo-benzene, norbornadiene, and transition metal based fulvalene-tetracarbonyl systems. Photodimerization of anthracene has been known for a century; however, this photoprocess has not been successfully exploited for MOST purposes due to its poor energy storage. Using well-calibrated theoretical methods on a series of [n.
View Article and Find Full Text PDFPeripheral neuropathy (PN) is a common disorder and presents as diagnostic and therapeutic challenge to physicians and neurologists. In epidemiological studies from India from various regions the overall prevalence of PN varied from 5 to 2400 per 10,000 population in various community studies. India is composed of a multiethnic, multicultural population who are exposed to different adverse environmental factors such as arsenic and lead.
View Article and Find Full Text PDFAlzheimer's disease and Parkinson's disease are two common neurodegenerative diseases of the elderly people that have devastating effects in terms of morbidity and mortality. The predominant form of the disease in either case is sporadic with uncertain etiology. The clinical features of Parkinson's disease are primarily motor deficits, while the patients of Alzheimer's disease present with dementia and cognitive impairment.
View Article and Find Full Text PDFThe breaking of bonds by catalytic electrons has gained prominence very recently but has been limited to cases where electrons from external sources have been used. Here, we show that upon photoexcitation, an electron of intramolecular origin is transferred from one part of a molecule to another followed by bond cleavage and then returns to its original moiety on completion of its catalytic function. By a proper assessment of the dramatic changes in aromaticity in excited-state intermediates along the photoreaction coordinate captured by the magnetically induced current density (MICD) technique, we show that in 5-phenyltetrazole, an excited electron, which migrates from the phenyl ring to the tetrazole ring, induces bond cleavage catalytically.
View Article and Find Full Text PDFAnn Indian Acad Neurol
August 2016
Introduction: Spinocerebellar ataxias (SCAs) are hereditary, autosomal dominant progressive neurodegenerative disorders showing clinical and genetic heterogeneity. They are usually manifested clinically in the third to fifth decade of life although there is a wide variability in the age of onset. More than 36 different types of SCAs have been reported so far and about half of them are caused by pathological expansion of the trinucleotide, Cytosine Alanine Guanine (CAG) repeat.
View Article and Find Full Text PDF