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Context: In the realm of quantum chemistry, the accurate prediction of electronic structure and properties of nanostructures remains a formidable challenge. Density functional theory (DFT) and density matrix renormalization group (DMRG) have emerged as two powerful computational methods for addressing electronic correlation effects in diverse molecular systems. We compare ground-state energies ( e 0 ), density profiles ( n ), and average entanglement entropies ( S ¯ ) in metals, insulators and at the transition from metal to insulator, in homogeneous, superlattices, and harmonically confined chains described by the fermionic one-dimensional Hubbard model. While for the homogeneous systems, there is a clear hierarchy between the deviations, D % (S ¯) < D % (e 0) < D ¯ % (n) , and all the deviations decrease with the chain size; for superlattices and harmonic confinement, the relation among the deviations is less trivial and strongly dependent on the superlattice structure and the confinement strength considered. For the superlattices, in general, increasing the number of impurities in the unit cell represents lower precision in the DFT calculations. For the confined chains, DFT performs better for metallic phases, while the highest deviations appear for the Mott and band-insulator phases. This work provides a comprehensive comparative analysis of these methodologies, shedding light on their respective strengths, limitations, and applications. Methods: The DFT calculations were performed using the standard Kohn-Sham scheme within the BALDA approach. It integrated the numerical Bethe-Ansatz (BA) solution of the Hubbard model as the homogeneous density functional within a local-density approximation (LDA) for the exchange-correlation energy. The DMRG algorithms were implemented using the ITensor library, which is based on the matrix product states (MPS) ansatz. The calculations were performed until the energy reaches convergence of at least 10 - 8 . [ABSTRACT FROM AUTHOR]

Several new direct-acting antiviral ( DAA) drugs are in development for chronic hepatitis C viral ( HCV) infection, and NS3- NS4A serine protease and the NS5B RNA-dependent RNA polymerase have been the major targets. HCV variants displaying drug-resistant phenotypes have been observed both in vitro and during clinical trials. Our aim was to characterize amino acid changes at positions previously associated with resistance in protease ( NS3) and polymerase ( NS5B) regions from treatment-naïve HCV patients infected with genotypes 1a, 1b and 3a. All 1383 NS3 protease sequences (genotype 1a = 680, 1b = 498 and 3a = 205) and 806 NS5B polymerase sequences (genotypes 1a = 471, 1b = 329, 3a = 6) were collected from Los Alamos databank. Genotype 3a protease sequences showed the typical low-level resistance mutation V36L. NS3 sequences from other genotypes presented mutations on positions 36, 39, 41, 43, 54, 80, 109, 155 and 168 in a frequency lower than 2%, except for the mutation Q80R found in 35% of genotype 1a isolates. Polymerase sequences from genotype 3a patients showed five typical mutations: L419I, I424V, I482L, V499A and S556G. Two positions presented high polymorphism in the NS5B region from genotype 1a (V499A) and genotype 1b (C316N) subjects. Our results demonstrated a natural profile of genotype 3a that can be associated with the pre-existence of HCV variants resistant to first-generation protease inhibitors and to non-nucleoside polymerase inhibitors. Likewise, genotype 1b isolates and genotype 1a sequences exhibited pre-existing mutations associated with resistance to Palm II and Thumb I polymerase inhibitors, respectively. [ABSTRACT FROM AUTHOR]

OBJECTIVES:: To determine the prevalence of the medial depression of mandibular ramus (MDMR) in dry human mandibles and in clinical panoramic radiographs and to compare the prevalence in dentoskeletal deformities with Angle Class I occlusion. METHODS:: Two hundred and fifty-one dry skulls and three groups of patients were used for this study: Group 1 consisted of 1358 panoramic radiographs from a general population, Group 2, 426 radiographs from individuals with Angle class I occlusion and Group 3283 individuals with dentoskeletal deformities. The prevalence of MDMR was determined in the skulls and each group and the shape from the radiographs alone. RESULTS:: The prevalence of MDMR in dry mandibles was 33.9% (bilateral in 13.1% and unilateral in 20.8%). MDMR was found in 276 radiographs (20.3% – Group 1 – bilateral in 40% and unilateral in 59.5%). MDMR was more common in Group 3 compared with Group 2 (χ2=35.98 P<0.01). A triangular MDMR was the most frequent (39.7%). CONCLUSION:: MDMR is a relatively common finding in panoramic radiographs. Patients with dentoskeletal deformities have a higher prevalence of MDMR and this should be taken into consideration if orthognathic surgery is proposed. [ABSTRACT FROM AUTHOR]

We study the local thermal entanglement in a spin-1/2 Ising-XXZ diamond structure with two impurities. In this spin chain, we have two impurities with an isolated XXZ dimer between them. We focus on the study of the thermal entanglement in this dimer. The main goal of this paper is to provide a good understanding of the effect of impurities in the entanglement of the model. This model is exactly solved by a rigorous treatment based on the transfer-matrix method. Our results show that the entanglement can be tuned by varying the impurities parameters in this system. In addition, it is shown that the thermal entanglement for such a model exhibits a clear performance improvement when we control and manipulate the impurities compared to the original model without impurities. Finally, the impurities can be manipulated to locally control the thermal entanglement, unlike the original model where it is done globally. [ABSTRACT FROM AUTHOR]