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Effect of electron correlation on single strand breaks (SSBs) induced by low energy electron (LEE) has been investigated in a fragment excised from a DNA, viz., 2′-deoxycytidine-3′-monophosphate [3′-dCMPH] molecule in gas phase at DFT-B3LYP/6-31+G(d) accuracy level and using local complex potential based time dependent wave packet (LCP-TDWP) approach. The results obtained, in conjunction with our earlier investigation, show the possibility of SSB at very low energy (0.15 eV) where the LEE transfers from π* to σ* resonance state which resembles a SN2 type mechanism. In addition, for the first time, an indication of quantum mechanical tunneling in strand breaking is seen from the highest anionic bound vibrational state (χ5), which may have a substantial role during DNA damage. [ABSTRACT FROM AUTHOR]

Selective cleaving of both O–H and O–D bonds in HOD is achieved using reasonably simple UV pulses to excite the HOD molecule in its ground vibrational state to the repulsive first excited à (1B1) surface. Detailed theoretical analysis of population transfer and flux in theH+O–D/H–O+D channels reveals an important preparatory role for the cross-talk between the participating levels and a possible role for the beat structure of the population transfer oscillations in facilitating selective dissociation. Excitation using a 50 fs single color 67 169 cm-1 laserpulse achieves a branching ratio H+O–D/H–O+D=5.64 with 82% flux in theH+O–D channel and 15% in the H–O+D channel. A two color 50 fs laser pulse with frequencies of 54 920 and 52 303 cm-1 provides a branching ratio of H–O+D/H+O–D=2.83 and 52% flux in the H–O+D channel and 18% in the H+O–D channel. [ABSTRACT FROM AUTHOR]

Vibrational excitation (νf←νi) cross-sections σνf←νi(E) in resonant e-N2 and e-H2 scattering are calculated from transition matrix elements Tνf,νi(E) obtained using Fourier transform of the cross correlation function <[lowercase_phi_synonym]νf(R)|ψνi(R,t)>, where ψνi(R,t)≃e-iHA2-(R)t/h[lowercase_phi_synonym]νi(R) with time evolution under the influence of the resonance anionic Hamiltonian HA2-(A2-=N2-/H2-) implemented using Lanczos and fast Fourier transforms. The target (A2) vibrational eigenfunctions [lowercase_phi_synonym]νi(R) and [lowercase_phi_synonym]νf(R) are calculated using Fourier grid Hamiltonian method applied to potential energy (PE) curves of the neutral target. Application of this simple systematization to calculate vibrational structure in e-N2 and e-H2 scattering cross-sections provides mechanistic insights into features underlying presence/absence of structure in e-N2 and e-H2 scattering cross-sections. The results obtained with approximate PE curves are in reasonable agreement with experimental/calculated cross-section profiles, and cross correlation functions provide a simple demarcation between the boomerang and impulse models. [ABSTRACT FROM AUTHOR]

The Fock space multireference coupled cluster based on an underlying bivariational self-consistent field is applied to the problem of computing complex energy associated with Auger and shape resonances in e-atom scattering. It is concluded that the Fock space multireference coupled cluster based on a bivariational self-consistent field provides a useful and practical approach to calculation of resonance parameters. Numerical results are presented for the [sup 2]P shape resonance of Mg and Auger 1 s-1 hole of Be. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

An examination of the dependence of total flux from competing photodissociation channels on the photolysis field parameters and initial vibrational states for IBr and HI molecules reveals that, for a range of field attributes, considerable selectivity and yield may be obtained by using only the ground or the ground and the first excited vibrational states in the optimal linear combination constituting the field optimized initial state (FOIST). The new simplifications obviate the need for overtone excitations or multicolor photolysis fields making it easier to implement FOIST experimentally. Concrete specifications of field attributes for achieving selective control of IBr photodissociation products is provided. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Quantum dynamical calculations are employed to study the significance of the photolysis frequency in enhancing the selectivity and yield for controlled bond breaking in HOD. The IR/UV pulse combinations are shown to provide extremely high selectivity and yield of the system.

The previous studies on polynitrogen compounds are extended to tautomeric isomers of the azolides by predicting their electron detachment energies and providing an analysis of the corresponding Dyson orbitals. The predicted transition energies have agreed well with low-intensity peaks in anion photoelectron spectra, which are assigned to less stable, tautomeric forms of these anions.

Examines the probability density profiles from the optimal superpositions of the field free vibrational eigenstates which maximize flux out of the desired photodissociation channels for IBr and HI molecules. Structure of the optimal superposition states; Selective flux maximization out of different channels; Absorption spectra and branching ratios.

In the area of biomaterials, fibers not only offer increased mechanical response, but also serve as an extracellular matrix mimicking morphology to direct cellular attachment and proliferation. While biologically similar in morphology, soft, and flexible hydrogel materials have low mechanical properties. For applications in tissue engineering, the lack of directional cues and attachment regions within the biogels is undesired as cells require a guide for adequate attachment and organized proliferation. In this work, we have investigated the role of poly(lactic acid) (PLA) fiber length and concentration as a reinforcement phase in a gelatin hydrogel matrix and the resultant mechanical and cellular responses. With increasing fiber length and concentration, the ultimate tensile strength, modulus, and toughness increased for the samples. Similarly, for shorter fiber lengths, the loss and storage modulus increased with fiber concentration. After seeding human mesenchymal stem cells (hMSCs) onto the neat fibrous scaffolds it was found that the fabrication process imparted no cytotoxicity. Furthermore, it was the concentrations and lengths of fiber both caused discernable differences in cell viability at the extreme values. Fibers of all lengths, when in a 4.0 wt % concentration, had a decrease in cell viability after 10 days while the 12.7 mm fibers showed a similar response at 2.0 wt %, but all stayed about 90% viability. With increased incubation time, hMSCs became elongated with increased proliferation. These results indicate that the wet‐lay process is a rapid and scalable method by which fibrous 3D‐scaffolds can be produced to reinforce hydrogel matrices. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 332–341, 2019. [ABSTRACT FROM AUTHOR]

The zeroth (Σ0), second order (Σ2), quasiparticle second order (Σ2q), diagonal two-particle one-hole Tamm Dancoff approximation (Σ2ph-TDA) and the quasiparticle diagonal 2ph-TDA (Σq2ph-TDA) decouplings have been applied to investigate the 2Π CO- and 2B2g C2H4- shape resonances. An examination of the resonant roots and the corresponding Feynman Dyson amplitudes (FDAs) reveals that the most economic and effective description is offered by the second order decoupling. The more demanding diagonal two-particle one-hole Tamm Dancoff approximation (2ph-TDA) is shown to be less effective and the quasiparticle decouplings are shown to be no better than the zeroth order (bivariational self-consistent field) approximation in the description of molecular shape resonances. The correlation and relaxation effects incorporated by the Σ2 and Σ2ph-TDA decouplings are shown to assist resonance formation by lowering the antibonding nature of the lowest unoccupied molecular orbitals (LUMOs) on the real line and by turning these into anionic diffuse orbitals suitable for metastable electron attachment for the optimal value of the complex scaling parameter. The use of complex resonance energies calculated here to construct a nonempirical optical potential for the investigation of vibrational dynamics of these resonances is suggested. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A new two-step procedure for laser control of photodissociation is presented. In the first step of the procedure, we show that control of photodissociation product yields can be exerted through preparation of the initial wave function prior to application of the photodissociation field in contrast to previous laser control studies where attention has focused on the design of the field which induces dissociation. Specifically, for a chosen channel from which maximum product yield is desired and a given photodissociation field, the optimal linear combination of vibrational eigenstates which comprise the initial wave function is found using a straightforward variational calculation. Any photodissociation pulse shape and amplitude can be assumed since the Schrödinger equation is solved directly. Application of this method to control of product yields in the photodissociation of hydrogen iodide is demonstrated. The second step of the control procedure involves the preparation of the coherent superposition of discrete levels obtained from the previous step; design of the preparatory field can be done analytically for two or three level systems as demonstrated here or with other well-studied iterative field design methods. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A general iterative inversion algorithm based on first-order functional sensitivity analysis and Tikhonov regularization is extended for the determination of diabatic coupling potentials from inelastic scattering data. For simplicity, the two-state case is presented here, and it is assumed that the (diagonal) diabatic potentials are known. ‘‘Noisy’’ and ‘‘noise-free’’ numerically simulated data, calculated from model potentials for He++Ne and Li+I, are used to illustrate the method. Various coupling potential trial functions are used, ranging from a constant multiple of the model to a step function. For most cases, the important regions of the coupling potential (i.e., those regions which are most sensitive to the inelastic scattering data, including the region of crossing) are recovered to high precision within four to seven iterations. Those cases which show a small range for convergence may indicate a limit of the present algorithm, based solely on first-order functional derivatives, and the need to extend it to include higher-order terms. [ABSTRACT FROM AUTHOR]

The orbital picture of shape resonances is investigated by examining the radial charge density distributions calculated from resonant Feynman–Dyson amplitudes for the 2P shape resonances in e-Be, e-Mg, and e-Ca scattering using the zeroth (bivariational self-consistent field), second order and the diagonal two particle one hole-Tamm–Dancoff approximation decouplings of the dilated electron propagator. A comparison between the radial density distributions from the highest occupied and the resonant orbital/Feynman–Dyson amplitude(s) reveals an accumulation of the electron density near the target for optimal value of the complex scaling parameter. The nodal pattern of the radial distributions differs from that expected for the lowest unoccupied p orbitals but their dominant contribution to the charge density distribution is clearly seen. A study of the difference between the radial densities obtained from various decoupling schemes highlights the role of correlation and relaxation in the characterization of these resonances. The role of coordinate space span of the primitive Gaussian-type orbital basis in characterization of these resonances is discussed. [ABSTRACT FROM AUTHOR]

Formulas for the renormalized full two-particle one hole-Tamm-Dancoff approximation (2ph-TDA) decoupling of the dilated biorthogonal electron propagator based on complex scaled bivariational self-consistent-field (SCF) procedure are derived and the diagonal 2ph-TDA approximation is implemented for the first time. The 2P shape resonances in e-Be, e-Mg, and e-Ca scattering are characterized using the diagonal 2ph-TDA, the second-order and the zeroth-order (bivariational SCF) approximations to the dilated electron propagator. A comparative investigation of these different decouplings reveals that although the resonance energies and widths depend on the level of correlation employed, greater correlation need not lead to sharper resonances. [ABSTRACT FROM AUTHOR]

Aim: This study aims to investigate the altered expression signature of long non-coding RNAs, mRNAs and deregulated pathways related to diabetic cardiomyopathy disease pathogenesis. Method: We utilize the previously established in vitro diabetic cardiomyopathy model of human induced pluripotent stem cell–derived human cardiomyocytes to perform long non-coding RNA and mRNA expression analysis on glucose (11 mM), endothelin-1 (10 nM) and cortisol (1 µM) stimulated human induced pluripotent stem cell–derived human cardiomyocytes to interrogate diabetic cardiomyopathy associated RNA expression profile. Result: Out of 20,730 mRNAs and 40,173 long non-coding RNAs being screened, 2046 long non-coding RNAs and 1582 mRNAs were differentially regulated (fold change > 2, p < 0.05) between diabetic cardiomyopathy and control group, of which more than half were intergenic and antisense long non-coding RNAs. Most of the coding transcripts were associated with processes like inflammation, structural reorganization, metabolism, smooth muscle contraction, focal adhesion and repair contributing towards the development of diabetic cardiomyopathy. The subgroup analysis further revealed 411 long non-coding RNAs being co-expressed with neighbouring genes. However, our coding–non-coding co-expression analysis showed an overall 48,155 co-expression network connections. In addition to that, the long non-coding RNAs with highest network connections were profoundly enriched for focal adhesion, cell-matrix adhesion and muscle contraction. Conclusion: These results provide comprehensive data about the pathways and regulatory mechanisms associated with diabetic cardiomyopathy and indicate that long non-coding RNAs may play a crucial role in diabetic cardiomyopathy. [ABSTRACT FROM AUTHOR]

Numerous adult diseases involving tissues consisting primarily of nondividing cells are associated with changes in DNA methylation. It suggests a pathophysiological role for de novo methylation or demethylation of DNA, which is catalyzed by DNA methyltransferase 3 and ten-eleven translocases. However, the contribution of DNA de novo (de)methylation to these diseases remains almost completely unproven. Broad changes in DNA methylation occurred within days in the renal outer medulla of Dahl SS rats fed a high-salt diet, a classic model of hypertension. Intrarenal administration of anti-DNA methyltransferase 3a/ten-eleven translocase 3 GapmeRs attenuated high salt-induced hypertension in SS rats. The high-salt diet induced differential expression of 1712 genes in the renal outer medulla. Remarkably, the differential expression of 76% of these genes was prevented by anti-DNA methyltransferase 3a/ten-eleven translocase 3 GapmeRs. The genes differentially expressed in response to the GapmeRs were involved in the regulation of metabolism and inflammation and were significantly enriched for genes showing differential methylation in response to the GapmeRs. These data indicate a significant role of DNA de novo (de)methylation in the kidney in the development of hypertension in SS rats. The findings should help to shift the paradigm of DNA methylation research in diseases involving nondividing cells from correlative analysis to functional and mechanistic studies. [ABSTRACT FROM AUTHOR]

Abstract: Bone marrow derived mesenchymal stem cells (BM‐MSC) is a promising alternative cell source to primary hepatocytes because of their ability to differentiate into hepatocyte‐like cells. However, their inability to differentiate efficiently and potential to turn into myofibroblasts restrict their applications. This study developed a plate coating from the liver extracellular matrix (ECM) and investigated its ability in facilitating the BM‐MSCs proliferation, hepatic differentiation, and hepatocyte‐specific functions during in vitro culture. After 28‐day culture, BM‐MSCs on the ECM coating showed hepatocyte‐like morphology, and certain cells took up low‐density lipoprotein. Synthesis of albumin, urea, and anti‐alpha‐fetoprotein, as well as expression of certain hepatic markers, in cells cultured on ECM were higher than cells cultured on non‐coated and Matrigel‐coated plates. mRNA levels of CYP3A4, albumin, CK18, and CYP7A1 in cells on ECM coating were significantly higher than cells cultured on the non‐coating environment. In conclusion, viability and hepatogenic differentiation of BM‐MSCs cultured on both Matrigel and ECM coating were significantly enhanced compared with those cultured on non‐coated plates. Moreover, the liver ECM coating induced additional metabolic functions relative to the Matrigel coating. The liver ECM hydrogel preserves the natural composition, promotes simple gelling, induces efficient stem cell hepatogenic differentiation, and may have uses as an injectable intermedium for hepatocytes. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 829–838, 2018. [ABSTRACT FROM AUTHOR]