Publications by authors named "Lazarov V"

Objectives: The 2022 US Supreme Court decision dramatically shifted the legal landscape in health care, leaving state legislatures to redefine the ethics of medical practice. As gold-standard medical procedures become banned and criminalized, physicians are facing heightened legal uncertainty and grappling with moral dilemmas of where and how to practice. This study aimed to quantitatively assess trends in legal concern among medical students and identify correlations with decision making regarding future medical training.

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Despite advancements in the field, early diagnosis of multiple endocrine neoplasia type 1 (MEN1) remains unachievable. This letter to the editor highlighted the importance of carefully assessing gastrointestinal symptoms, hypercalcemia, and elevated serum gastrin levels, as suggested by Yuan in their paper. They focused on a patient with recurrent abdominal pain and diarrhea whose diagnostic path led to establishing a MEN1 diagnosis within a year.

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A surfactant-free ammonia and carbamide precursor-modulated engineering of self-assembled flower-like 3D NiO nanostructures based on ordered β-Ni(OH) and turbostratic Ni(OH)(NO) nanoplate-structured intermediates is reported. By employing complementary structural and spectroscopic techniques, fundamental insights into structural and chemical transformations from intermediates to NiO nanoparticles (NPs) are provided. FTIR, Raman and DSC analyses show that the transformation of intermediates to NiO NPs involves subsequent loss of NO and OH species through a double-step phase transformation at 306 and 326 °C corresponding to the loss of free interlayer ions and HO species, respectively, followed by the loss of chemically bonded OH and NO ions.

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Thiol-reactive Michael acceptors are commonly used for the formation of chemically cross-linked hydrogels. In this paper, we address the drawbacks of many Michael acceptors by introducing pyridazinediones as new cross-linking agents. Through the use of pyridazinediones and their mono- or dibrominated analogues, we show that the mechanical strength, swelling ratio, and rate of gelation can all be controlled in a pH-sensitive manner.

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Forming semiconductor heterojunctions is a promising strategy to boost the efficiency of solar-driven photoelectrochemical (PEC) water splitting by accelerating the separation and transport of photogenerated charge carriers via an interfacial electric field. However, there is limited research considering the influence of electrolytes on the band alignment of the heterojunction under PEC conditions. In this work, we use a single crystal NiCoO/SrTiO (NCO/STO) heterojunction with atomic-precision controlled thickness as a model photoelectrode to study the band structure modulations upon getting in contact with the electrolyte and the correlation with the PEC activity.

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First principles modeling of anatase TiO surfaces and their interfacial contacts shows that defect-induced trap states within the band gap arise from intrinsic structural distortions, and these can be corrected by modification with Zr(IV) ions. Experimental testing of these predictions has been undertaken using anatase nanocrystals modified with a range of Zr precursors and characterized using structural and spectroscopic methods. Continuous-wave electron paramagnetic resonance (EPR) spectroscopy revealed that under illumination, nanoparticle-nanoparticle interfacial hole trap states dominate, which are significantly reduced after optimizing the Zr doping.

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Photoelectrochemical (PEC) devices have been developed for direct solar fuel production but the limited stability of submerged light absorbers can hamper their commercial prospects. Here, we demonstrate photocathodes with an operational H evolution activity over weeks, by integrating a BiOI light absorber into a robust, oxide-based architecture with a graphite paste conductive encapsulant. In this case, the activity towards proton and CO reduction is mainly limited by catalyst degradation.

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The spatial distributions of antibonding π^{*} and σ^{*} states in epitaxial graphene multilayers are mapped using electron energy-loss spectroscopy in a scanning transmission electron microscope. Inelastic channeling simulations validate the interpretation of the spatially resolved signals in terms of electronic orbitals, and demonstrate the crucial effect of the material thickness on the experimental capability to resolve the distribution of unoccupied states. This work illustrates the current potential of core-level electron energy-loss spectroscopy towards the direct visualization of electronic orbitals in a wide range of materials, of huge interest to better understand chemical bonding among many other properties at interfaces and defects in solids.

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Background: Few studies have explored the association between stroke thrombectomy (ST) volume and hospital accreditation with clinical outcomes.

Objective: To assess the association of ST case volume and accreditation status with in-hospital mortality and home discharge disposition using the national Medicare Provider Analysis and Review (MEDPAR) database.

Methods: Rates of hospital mortality, home discharge disposition, and hospital stay were compared between accredited and non-accredited hospitals using 2017-2018 MEDPAR data.

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Carbon dots (CDs) are an emerging class of photoluminescent material. Their unique optical properties arise from the discrete energy levels in their electronic states, which directly relate to their crystalline and chemical structure. It is expected that when CDs go through structural changes chemical reduction or thermal annealing, their energy levels will be altered, inducing unique optoelectronic properties such as solid-state photoluminescence (PL).

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Introduction: The Flow Redirection Endoluminal Device (FRED; MicroVention) is a dual-layered flow diverter used for the treatment of intracranial aneurysms. The objective of this systematic review was to compile device-related safety and effectiveness data.

Methods: The literature from January 1, 2013 to April 30, 2021 was searched for studies describing use of the FRED for intracranial aneurysm treatment irrespective of aneurysm location and morphology.

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Anti-phase boundaries (APBs) are structural defects which have been shown to be responsible for the anomalous magnetic behavior observed in different nanostructures. Understanding their properties is crucial in order to use them to tune the properties of magnetic materials by growing APBs in a controlled way since their density strongly depends on the synthesis method. In this work we investigate their influence on magnetite (FeO) thin films by considering an atomistic spin model, focussing our study on the role that the exchange interactions play across the APB interface.

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InO is a wide bandgap oxide semiconductor, which has the potential to be used as an active material for transparent flexible electronics and UV photodetectors. However, the high concentration of unintentional background electrons existing in InO makes it hard to be modulated by the electric field or form p-n heterojunctions with a sufficient band-bending width at the interface. In this work, we report the reduction of the background electrons in InO by Mg doping (Mg-InO) and thereby improve the device performance of p-n diodes based on the NiO/Mg-InO heterojunction.

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Properdin is the only positive regulator of the complement system. In this study, we characterize the prevalence, functional consequences and disease associations of autoantibodies against properdin in a cohort of patients with autoimmune disease systemic lupus erythematosus (SLE) suffering from lupus nephritis (LN). We detected autoantibodies against properdin in plasma of 22·5% of the LN patients (16 of 71) by enzyme-linked immunosorbent assay (ELISA).

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FeO nanoparticles are one of the most promising candidates for biomedical applications such as magnetic hyperthermia and theranostics due to their bio-compatibility, structural stability and good magnetic properties. However, much is unknown about the nanoscale origins of the observed magnetic properties of particles due to the dominance of surface and finite size effects. Here we have developed an atomistic spin model of elongated magnetite nanocrystals to specifically address the role of faceting and elongation on the magnetic shape anisotropy.

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Previous first-principles calculations have failed to reproduce many of the key thermoelectric features of FeVAl, e.g. the maximum values of the Seebeck coefficient S and its asymmetry with respect to the chemical potential.

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From simple averaging to more sophisticated registration and restoration strategies, such as super-resolution (SR), there exist different computational techniques that use a series of images of the same object to generate enhanced images where noise and other distortions have been reduced. In this work, we provide qualitative and quantitative measurements of this enhancement for high-angle annular dark-field scanning transmission electron microscopy imaging. These images are compared in two ways, qualitatively through visual inspection in real and reciprocal space, and quantitatively, through the calculation of objective measurements, such as signal-to-noise ratio and atom column roundness.

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Natural killer (NK) cells can discriminate between normal and cancer cells and are known to directly recognize and kill malignant cells or induce apoptosis. Thus, activation of NK cells is considered as a promising strategy for cancer treatment. However, clinical application has been somewhat limited because of difficulties in the preparation of sufficient number of highly cytotoxic/activated NK cells .

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The complement component C3 is at the heart of the complement cascade. It is a complex protein, which generates different functional activated fragments (C3a, C3b, iC3b, C3c, C3d). C3b is a constituent of the alternative pathway C3 convertase (C3bBb), binds multiple regulators, and receptors, affecting thus the functioning of the immune system.

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Magnetic nanoparticles (MNPs) have become increasingly important in biomedical applications like magnetic imaging and hyperthermia based cancer treatment. Understanding their magnetic spin configurations is important for optimizing these applications. The measured magnetization of MNPs can be significantly lower than bulk counterparts, often due to canted spins.

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The depth-resolved chemical structure and magnetic moment of [Formula: see text], thin films grown on Si(1 1 1) have been determined using x-ray and polarized neutron reflectometry. Bulk-like magnetization is retained across the majority of the film, but reduced moments are observed within 45[Formula: see text] of the surface and in a 25[Formula: see text] substrate-interface region. The reduced moment is related to compositional changes due to oxidation and diffusion, which are further quantified by elemental profiling using electron microscopy with electron energy loss spectroscopy.

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Most of the magnetic devices in advanced electronics rely on the exchange bias effect, a magnetic interaction that couples a ferromagnetic and an antiferromagnetic material, resulting in a unidirectional displacement of the ferromagnetic hysteresis loop by an amount called the 'exchange bias field'. Setting and optimizing exchange bias involves cooling through the Néel temperature of the antiferromagnetic material in the presence of a magnetic field. Here we demonstrate an alternative process for the generation of exchange bias.

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Understanding the energetics at the interface, including the alignment of valence and conduction bands, built-in potentials, and ionic and electronic reconstructions, is an important challenge in designing oxide interfaces that have controllable multifunctionalities for novel (opto-)electronic devices. In this work, we report detailed investigations on the heterointerface of wide-band-gap p-type NiO and n-type SrTiO (STO). We show that despite a large lattice mismatch (∼7%) and dissimilar crystal structure, high-quality NiO and Li-doped NiO (LNO) thin films can be epitaxially grown on STO(001) substrates through a domain-matching epitaxy mechanism.

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The structural, chemical, and magnetic properties of magnetite nanoparticles are compared. Aberration corrected scanning transmission electron microscopy reveals the prevalence of antiphase boundaries in nanoparticles that have significantly reduced magnetization, relative to the bulk. Atomistic magnetic modelling of nanoparticles with and without these defects reveals the origin of the reduced moment.

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Halfmetal-semiconductor interfaces are crucial for hybrid spintronic devices. Atomically sharp interfaces with high spin polarisation are required for efficient spin injection. In this work we show that thin film of half-metallic full Heusler alloy CoFeSiAl with uniform thickness and B2 ordering can form structurally abrupt interface with Ge(111).

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