Publications by authors named "Havu V"

Hybrid density functional approximations (DFAs) offer compelling accuracy for ab initio electronic-structure simulations of molecules, nanosystems, and bulk materials, addressing some deficiencies of computationally cheaper, frequently used semilocal DFAs. However, the computational bottleneck of hybrid DFAs is the evaluation of the non-local exact exchange contribution, which is the limiting factor for the application of the method for large-scale simulations. In this work, we present a drastically optimized resolution-of-identity-based real-space implementation of the exact exchange evaluation for both non-periodic and periodic boundary conditions in the all-electron code FHI-aims, targeting high-performance central processing unit (CPU) compute clusters.

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The protection of halide perovskites is important for the performance and stability of emergent perovskite-based optoelectronic technologies. In this work, we investigate the potential inorganic protective coating materials ZnO, SrZrO, and ZrO for the CsPbI perovskite. The optimal interface registries are identified with Bayesian optimization.

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The effects of alkali postdeposition treatment (PDT) on the valence band structure of Cu(In,Ga)Se (CIGSe) thin-film solar cell absorbers are addressed from a first-principles perspective. In detail, experimentally derived hard X-ray photoelectron spectroscopy (HAXPES) data [ Handick , E. ; ACS Appl.

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The conductivity of carbon nanotube thin films is mainly determined by carbon nanotube junctions, the resistance of which can be reduced by several different methods. We investigate electronic transport through carbon nanotube junctions in a four-terminal configuration, where two metallic single-wall carbon nanotubes are linked by a group 6 transition metal atom. The transport calculations are based on the Green's function method combined with the density-functional theory.

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Obtaining the eigenvalues and eigenvectors of large matrices is a key problem in electronic structure theory and many other areas of computational science. The computational effort formally scales as O(N(3)) with the size of the investigated problem, N (e.g.

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We derive equations for nonadiabatic Ehrenfest molecular dynamics within the projector augmented-wave (PAW) formalism. The discretization of the electrons is time-dependent as the augmentation functions depend on the positions of the nuclei. We describe the implementation of the Ehrenfest molecular dynamics equations within the real-space PAW method.

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We present an all-electron method for time-dependent density functional theory which employs hierarchical nonuniform finite-element bases and the time-propagation approach. The method is capable of treating linear and nonlinear response of valence and core electrons to an external field. We also introduce (i) a preconditioner for the propagation equation, (ii) a stable way to implement absorbing boundary conditions, and (iii) a new kind of absorbing boundary condition inspired by perfectly matched layers.

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We show that the type 2 Broyden secant method is a robust general purpose mixer for self consistent field problems in density functional theory. The Broyden method gives reliable convergence for a large class of problems and parameter choices. We directly mix the approximation of the electronic density to provide a basis independent mixing scheme.

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We present for static density functional theory and time-dependent density functional theory calculations an all-electron method which employs high-order hierarchical finite-element bases. Our mesh generation scheme, in which structured atomic meshes are merged to an unstructured molecular mesh, allows a highly nonuniform discretization of the space. Thus it is possible to represent the core and valence states using the same discretization scheme, i.

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We have modeled transport properties of nanostructures using Green's-function method within the framework of the density-functional theory. The scheme is computationally demanding, so numerical methods have to be chosen carefully. A typical solution to the numerical burden is to use a special basis-function set, which is tailored to the problem in question, for example, the atomic-orbital basis.

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Laser Doppler flux (LDF) is a product of the concentration of moving blood cells (CMBC) and the blood cell velocity (BCV). In an attempt to obtain more information about the cutaneous microcirculation in legs with venous ulcers and in healthy legs, the dynamics of the curves of the LDF, the CMBC, and the BCV were analyzed in 8 patients with venous leg ulcers and in 10 subjects with healthy legs. The curves of the CMBC and of the BCV were found to be in opposite phases both in the ulcerous legs and in the healthy legs.

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In a randomized, double-blind, double-placebo, multicentre study, terbinafine 250 mg daily for 12 weeks was compared with fluconazole 150 mg once weekly for 12 or 24 weeks in the treatment of onychomycosis. A total of 137 patients with culture-confirmed onychomycosis was divided into three groups: group A received terbinafine for 12 weeks, group B received fluconazole for 12 weeks, while group C received fluconazole for 24 weeks. At completion of the study (week 60), the mycological cure rate was higher in the terbinafine group than in the fluconazole groups: 89% vs.

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A series of 120 biopsies from benign (verruca vulgaris and keratoacanthoma), premalignant (actinic keratosis and extragenital Bowen's disease) and malignant (squamous cell carcinoma) skin lesions were studied immunohistochemically for the expression of cell-cycle proteins p53, p21 (WAF-1), PCNA and Ki-67. The presence of human papillomavirus (HPV) DNA in these samples had been analysed previously using in situ hybridization (ISH) and PCR. Moderate to intense expression of both PCNA and Ki-67 was present in most of the lesions studied.

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In an attempt to clarify the pathophysiology of haemodynamics in legs with venous ulcer we investigated the effect of a single intermittent pneumatic compression treatment on the peripheral resistance of leg arteries and the cutaneous laser Doppler flux in the leg. Eight patients with venous leg ulcers and 10 subjects with healthy legs were investigated. Doppler waveforms of the leg arteries and laser Doppler flux of the leg skin were recorded before and after a single intermittent pneumatic compression treatment with the subjects in a recumbent position.

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This multicentre, double-blind, randomized study compared the pharmacokinetics of itraconazole given at 200 mg once daily for 3 months and intermittently at 200 mg twice daily for 1 week per month followed by a 3-week drug-free period for 3 months in the treatment of onychomycosis. Patients were followed for 9 months after treatment. Itraconazole and hydroxy-itraconazole plasma concentrations and itraconazole nail tip concentrations were determined at regular intervals.

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In this multicentre, double-blind, parallel group study, we evaluated the efficacy and safety of continuous treatment with itraconazole, 200 mg daily for 3 months, in comparison with itraconazole pulse therapy, 400 mg daily 1 week per month for 3 months, in the treatment of toe-nail onychomycosis. The study included 129 patients with distal subungual onychomycosis of the toe-nails, confirmed by microscopy and positive for dermatophyte culture; 65 received continuous treatment and 64 received pulse therapy. Patients were followed up for 9 months after treatment.

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Background: Onychomycosis of the toenail caused by nondermatophyte molds alone or in combination with dermatophytes is difficult to eradicate with standard antifungal therapy.

Objective: Our purpose was to determine the effectiveness of itraconazole in the treatment of toenail onychomycosis caused by molds alone or in combination with dermatophytes.

Methods: We treated 36 patients with this drug given as continuous dosing (100 or 200 mg/ day) for 6 to 20 weeks or as a 1-week pulse dosing (200 mg twice daily for 1 week per month) for two to four pulses.

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There are conflicting reports in the literature about the existence of arteriovenous shunting in legs with chronic venous insufficiency. Using duplex scanning, we have earlier shown that there is lowered peripheral resistance in the arteries of legs with venous ulcer together with premature venous filling in angiography. In the present study we investigated the peripheral resistance in the arteries of 16 legs with chronic venous insufficiency without present ulcer.

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To assess the role of human papillomavirus (HPV) in the aetiology of extragenital Bowen's disease (EBD), a series of 91 cases were analysed using in situ hybridization (ISH) with whole genomic DNA probes of HPV types 1, 2, 4, 6, 7, 11, 12, 15, 16, 18, 26, 36, 37, 39, 42, 55 and 59. No HPV DNA was found in any of the samples tested. A polymerase chain reaction (PCR) was also used to analyse 37 of the 91 samples, using both the consensus primers MY09/MY11 which amplify a large number of HPV types from the L1 region and the degenerate primers CP65/CP70, which amplify the complete set of epidermodysplasia verruciformis (EV) HPV types.

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A series of 90 excised cutaneous warts (verrucae vulgaris) were studied for the presence of HPV (human papillomavirus) DNA using in situ hybridization (ISH) with biotinylated full genomic DNA probes of HPV types 1, 2, 3, and 4. The expression of PCNA (proliferating cell nuclear antigen) was examined using conventional immunohistochemistry. The aim was to test the hypothesis that HPV can reactivate PCNA, including in the host replication machinery.

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Certain HPV types have been linked to the genesis and development of premalignant and malignant skin diseases. There have been several contradictory reports on the role of HPV infections in the development of keratoacanthomas (KAs). To further study the involvement of HPVs in the aetiology of KAs, we investigated paraffin-embedded specimens of 80 biopsies of KAs for the presence of HPV 1, 2, 3, 4, 5, 7, 26, 37, 38, 47 and 59 DNA by in situ hybridization (ISH) with biotinylated probes under high stringency conditions (Tm-10 degrees C).

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Human papillomaviruses (HPVs) are involved in premalignant and malignant skin diseases as well as in a variety of benign cutaneous and mucosal lesion disease. Its association with HPV infection has recently been evaluated in a few studies, but the results are contradictory. For further assessment of the role of HPVs in AK, a series of 100 paraffin-embedded biopsy specimens taken from subjects with AK were studied for the presence of HPV types 1, 2, 3, 4, 5, 7, 12, 15, 26, 36, 37 and 59 DNA using in situ hybridization (ISH) under high stringency conditions (Tm -10 degrees C).

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In the literature there is disagreement concerning the existence of arteriovenous shunting in legs with venous ulcer(s). The aim of this study was to find out if there are differences in resistance in the arteries of ulcer legs and non-ulcer legs and if it is possible to investigate this with a non-invasive Doppler method. Eleven patients, aged 34-87 years, with venous ulcer only in one leg, were investigated using angiography and duplex scanning.

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