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1.
Phys Chem Chem Phys ; 26(8): 6977-6983, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38344751

RESUMO

Covalent organic frameworks can be used for next-generation rechargeable metal-ion batteries due to their controllable spatial and chemical architectures and plentiful elemental reserves. In this study, the arsenic-based covalent organic framework (As-COF) is designed by employing the geometrical symmetry of a semiconducting phosphazene-based covalent organic framework that uses p-phenylenediamine as a linker and hexachorocyclotriphosphazene as an As-containing monomer in a C3-like spatial configuration. The As-COF with engineered nanochannels demonstrates exceptional anodic behavior for potassium (K) and calcium (Ca) ion batteries. It exhibits a high storage capacity of about 914(2039) mA h g-1, low diffusion barriers of 0.12(0.26) eV, low open circuit voltage of 0.23(0.18) V, and a minimal volume expansion of 2.41(2.32)% for K (Ca) ions. These attributes collectively suggest that As-COF could significantly advance high-capacity rechargeable batteries.

2.
Cureus ; 13(11): e19768, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34950547

RESUMO

Background and aim For years, interferon-based treatment has been offered to patients with chronic hepatitis C virus (HCV) infection; however, the complexity of the treatment, efficacy, and adverse effects were the primary concerns. All these concerns were addressed with the introduction of directly acting antivirals (DAAs) to treat chronic HCV. Sofosbuvir and velpatasvir are second-generation DAAs used in combination for the treatment of chronic HCV infection. The aim of our study was to determine and compare the efficacy and safety profile of the sofosbuvir and velpatasvir combination in treating patients with chronic hepatitis C with or without cirrhosis. Materials and methods This descriptive study was conducted at the Department of Medicine, Khyber Teaching Hospital, Peshawar, from March 15th to September 15th, 2021 after approval from the Institution Research and Ethical Review Board (IREB). Diagnosis of HCV was based on the detection of hepatitis C ribonucleic acid (RNA) fragments by reverse transcription-polymerase chain reaction (RT-PCR). Liver status was assessed with liver function tests and imaging. Sofosbuvir (400 mg) and velpatasvir (100 mg) were administered once daily for 12 weeks, followed by polymerase chain reaction (PCR) for HCV RNA after 12 weeks of completion of treatment for determination of sustained virologic response at 12 weeks (SVR12). Patients with cirrhosis also received weight-based ribavirin. Adverse events experienced by the study participants during the course of treatment were recorded. Data were collected regarding patients' demographics, laboratory parameters, SVR12, and adverse events, and were then analyzed using SPSS, version 22 (IBM SPSS Statistics, Armonk, NY). Results A total of 58 patients with cirrhosis and 58 patients without cirrhosis with chronic HCV were enrolled. The rate of SVR12 in patients with cirrhosis was 89.7% (52 patients achieved SVR12), compared to 98.3% in patients without cirrhosis (57 patients achieved SVR12). Subgroup analysis of patients with cirrhosis revealed that patients who have failed to achieve SVR12 were mostly males, had prolonged disease duration, and low hemoglobin at baseline; however, the association of these factors with SVR12 was not significant. The incidence of adverse events among all study participants was 46.5%. Among the cirrhotic cohort, 37 (63.8%) patients experienced adverse events, while only 17 (29.3%) patients among the non-cirrhotic cohort had adverse events. A total of 24 patients with cirrhosis (41.37%) reported mild complaints. The most commonly reported adverse event was gastrointestinal (GI) upsets (46.2%), followed by fatigue (33.9%), while 19.9% developed miscellaneous adverse events such as headaches, rash, and insomnia. Conclusion The combination of sofosbuvir and velpatasvir is highly effective and safe in patients with HCV with or without cirrhosis. However, this combination's efficacy was slightly higher in non-cirrhotic patients (98.3%) than in cirrhotic patients (89.7%).

3.
J Phys Condens Matter ; 33(21)2021 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-33684897

RESUMO

Two-dimensional heterostructures formed by stacking layered materials play a significant role in condensed matter physics and materials science due to their potential applications in high-efficiency nanoelectronic and optoelectronic devices. In this paper, the structural, electronic, and optical properties of SiC/CrS2van der Waals heterostructure (vdWHs) have been investigated by means of density functional theory calculations. It is confirmed that the SiC/CrS2vdWHs is energetically and thermodynamically stable indicating its great promise for experimental realization. We find that the SiC/CrS2vdWHs has a direct-band gap and type-II (staggered) band alignment, which can effectively separate the photo-induced electrons and holes pairs and extend their life time. The carrier mobilities of electrons and holes along the armchair and zigzag directions are as high as 6.621 × 103and 6.182 × 104 cm2 V-1 s-1, respectively. Besides, the charge difference and potential drop across the interface can induce a large built-in electric field across the heterojunction, which will further hinder the electron and hole recombination. The SiC/CrS2vdWHs has enhanced optical absorption capability compared to individual monolayers. This study demonstrates that the SiC/CrS2vdWHs is a good candidate for application in the nanoelectronic and optoelectronic devices.

4.
Phys Chem Chem Phys ; 22(38): 21858-21871, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-32966442

RESUMO

Crystal growth with various patterns, hexagonal, circular, square, rectangular, star-like, and faceted, was investigated using the one-mode approximation of phase-field crystal (PFC) modeling. The simulations were carried out at different temperatures and average densities of the diverse patterns. The pattern selection of crystal growth is caused by the competition between undercooling temperature ε and average density ψ. When the undercooling temperature reaches ε = -0.75, the crystal evolves into a stable striped phase. Further increasing from ε = -0.75 to -0.25, a combination of a triangular-striped coexistence pattern, a triangular-liquid coexistence phase and a stable triangular pattern forms with average densities ψ = -0.130, -0.185 and -0.285, respectively. In particular, when the time, undercooling temperature and average density increase, the crystal grows to a secondary pattern. The introduction of noise terms breaks the symmetry in the growth morphology. For a hexagonal lattice, a large undercooling temperature ε leads to faster crystallization. Finally, a morphological phase diagram under the effect of ε and ψ with star-like dendrite and compact spherical shape (CSS) is constructed as a function of the phase-field crystal parameters.

5.
J Mol Graph Model ; 98: 107620, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32311661

RESUMO

Exploring highly spin-polarized materials is crucial for the development of spin-based devices. In this paper, we investigate the atomic structure, electronic, half-metallic and magnetic properties of the CsCrZ2 (Z = O, S, Se or Te) Heusler alloys, by performing first-principles calculations based on density functional theory (DFT). The geometry optimization process shows that the alloys are more stable in Cu2MnAl type structure than in Hg2CuTi one. To find a magnetic ground state, the total energy of the alloys is calculated in the non-magnetic (NM), ferromagnetic (FM) and anti-ferromagnetic (AFM) ordering. We find that, the FM ordering yields the lowest energy, thereby confirming that the alloys are FM in the ground state. On computing the cohesive and formation energy in the ground state, it is found that alloys are chemically and thermodynamically stable, respectively. Spin polarized band structures and density of states (DOS) demonstrate that the CsCrO2, CsCrS2 and CsCrSe2 alloys are true half-metals with 100% spin-polarization at the Fermi level, while the CsCrTe2 alloy is predicted as highly spin polarized material. Furthermore, the CsCrO2, CsCrS2 and CsCrSe2 alloys possess 2.529, 2.250 and 2.050 eV gaps in the spin down band structure, respectively. The calculated total magnetic moments reveal that half-metallic alloys have an integral total magnetic moment of 3.000 µB, which satisfies the Slater-Pauling rule Mt = Zt-16. The main contribution to the total magnetic moment comes from the Cr atoms (about 3.9 µB). Furthermore, the Curie temperature TC calculated within classical Heisenberg model is estimated to be about 822 K (CsCrO2), 685 K (CsCrS2), 753 K (CsCrSe2) and 636 K (CsCrTe2). The obtained high spin polarization and above room temperature FM ordering make the materials as promising materials to be used in spintronic technology.


Assuntos
Ligas , Imãs , Eletrônica , Magnetismo , Metais
6.
J Phys Condens Matter ; 32(32): 325001, 2020 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-32209744

RESUMO

Thin films with stable half-metallic (HM) character and 100% spin-polarization (SP) are required to be used in spintronic devices. The HM character has been predicted theoretically in many Heusler alloys thin films and confirmed by experiments. Full-Heusler alloy Ti2FeSn has been studied extensively. It has been reported that their (001)-oriented thin films with TiFe or TiSn terminations preserve 100% SP, but the HM character is unstable because the edge of the bandgap is closed to the Fermi level E F. Therefore, we investigate the effects of the Co-doping on the structural, electronic and magnetic properties of the bulk full-Heusler alloys Ti2Fe1-x Co x Sn (x = 0.00, 0.25, 0.50, 0.75 or 1.00) and their (001)-oriented thin films. The bulk Ti2Fe1-x Co x Sn (x = 0.00, 0.25, 0.50, 0.75 or 1.00) alloys are all HM ferromagnets. We investigate twelve possible terminations and show that five of them preserve HM character with 100% SP at the Fermi level E F, while in the remaining seven, surface states emerge in the spin-down channel at the Fermi level E F, significantly reducing their SP. The Co-doping significantly increases the stability of the TiSn slab, also increases its spin-down bandgap [Formula: see text] and HM gap [Formula: see text] at x = 0.50. The stable HM character makes it is a slab of maximum benefit in the applications of spintronic devices, especially in magnetic tunnel junctions.

7.
Cureus ; 12(1): e6537, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32042516

RESUMO

Background In Pakistan, there is a paucity of published clinical data regarding the efficacy of sofosbuvir-velpatasvir in the management of patients with hepatitis C without cirrhosis or with compensated cirrhosis. Methods A prospective, open-label, multicenter, interventional trial was conducted in patients with hepatitis C without cirrhosis or with compensated cirrhosis. Hepatitis C patients without cirrhosis or with compensated cirrhosis were screened, and 133 patients were enrolled in the study. They received sofosbuvir 400 mg plus velpatasvir 100 mg combination once daily for 12 weeks. Patients were followed up for six months after the start of therapy. Hepatitis C viral load was assessed at baseline, at week 12, and after 24 weeks following the start of the treatment. The trial was prospectively registered with the Iranian Registry of Clinical Trials (IRCT) with the identification number IRCT20170614034526N4. Results Among enrolled patients, 79 were male, and 54 were female. Ninety-five (71.4%) patients were without cirrhosis, and 38 had compensated cirrhosis. Patients without cirrhosis had a mean age of 45.90 ±10.99 years, and patients with compensated cirrhosis had a mean age of 52.60 ±12.29 years. As per the intention-to-treat analysis, all patients without cirrhosis and 35 (92.1%) patients with compensated cirrhosis achieved undetectable viral load hepatitis C virus (HCV) ribonucleic acid (RNA) of <15 IU/mL at 12 weeks from the start of treatment. Eighty-six (90.5%) patients without cirrhosis achieved sustained virologic response 12 weeks after the end of therapy. Patients with compensated cirrhosis experienced more adverse events (31.5%) than patients without cirrhosis (20.15%). Conclusion Direct-acting antiviral therapy using sofosbuvir and velpatasvir combination is effective and safe in HCV patients without cirrhosis and patients with compensated cirrhosis.

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