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1.
Front Psychiatry ; 14: 1254147, 2023.
Article in English | MEDLINE | ID: mdl-37840784

ABSTRACT

Introduction: To decrease psychological risk for content moderators, the study initiated the first steps of developing a robust employment screening tool, namely, the Cognitive Adaptability and Resiliency Employment Screener. Method: The study consisted of three phases with 4,839 total participants. Results: In Phase 1, a set of 76 items were developed and tested via exploratory factor analysis, yielding three factors (i.e., Psychological Perseverance & Agility, Rumination & Emotional Lingering, and Expressiveness & Sociability) and also reducing the scale to 68 items. In Phase 2 through confirmatory factor analysis, the three-factor structure showed good fit (CFI = 0.92, RMSEA = 0.05) and demonstrated sufficient overall reliability. In Phase 3, the convergent validity and divergent validity of the tool were established relative to constructs such as resilience, cognitive control and flexibility, emotion regulation, and optimism. Discussion: Altogether, the findings revealed that the scale demonstrated good psychometric properties that, pending future studies, may serve as a promising employment screener for content moderators.

2.
Sci Adv ; 6(34): eabb3188, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32875111

ABSTRACT

Development of the new-generation membranes for tunable molecular separation requires materials with abilities beyond strict separation. Stimuli response could remotely adjust the membrane selectivity. Azobenzene derivatives can be photo-switched between trans and cis isomers under ultraviolet or visible light. Here, the azobenzenes were implanted as light switches to bridge the flexible cyclen building blocks. The smart covalent organic network membranes fold and unfold as origami that can be photo-switched between on-state (large) and off-state (small) pores. The cis membranes with off state under ultraviolet (UV) light have higher dye rejection than trans membranes with on-state channels. By controlling the trans-to-cis azobenzene isomerization via UV/Vis light, the pore size can be remotely controlled at the molecular level and the solvent permeance and dye rejection can be dynamically tuned.

3.
Polymers (Basel) ; 12(6)2020 Jun 25.
Article in English | MEDLINE | ID: mdl-32630598

ABSTRACT

Newer non-ionic amphiphiles have been synthesized using biocompatible materials and by following a greener approach i.e., D-glucitol has been used as a template, and hydrophobic and hydrophilic segments were incorporated on it by using click chemistry. The hydrophilic segments in turn were prepared from glycerol using an immobilized Candida antarctica lipase (Novozym-435)-mediated chemoenzymatic approach. Surface tension measurements and dynamic light scattering studies reflect the self-assembling behavior of the synthesized amphiphilic architectures in the aqueous medium. The results from UV-Vis and fluorescence spectroscopy establish the encapsulation of guests in the hydrophobic core of self-assembled amphiphilic architectures. The results of 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay indicate that the amphiphiles are well tolerated by the used A549 cell lines at all tested concentrations.

4.
Phys Rev Lett ; 124(5): 057201, 2020 Feb 07.
Article in English | MEDLINE | ID: mdl-32083901

ABSTRACT

Magnets with chiral crystal structures and helical spin structures have recently attracted much attention as potential spin-electronics materials, but their relatively low magnetic-ordering temperatures are a disadvantage. While cobalt has long been recognized as an element that promotes high-temperature magnetic ordering, most Co-rich alloys are achiral and exhibit collinear rather than helimagnetic order. Crystallographically, the B20-ordered compound CoSi is an exception due to its chiral structure, but it does not exhibit any kind of magnetic order. Here, we use nonequilibrium processing to produce B20-ordered Co_{1+x}Si_{1-x} with a maximum Co solubility of x=0.043. Above a critical excess-Co content (x_{c}=0.028), the alloys are magnetically ordered, and for x=0.043, a critical temperature T_{c}=328 K is obtained, the highest among all B20-type magnets. The crystal structure of the alloy supports spin spirals caused by Dzyaloshinskii-Moriya interactions, and from magnetic measurements we estimate that the spirals have a periodicity of about 17 nm. Our density-functional calculations explain the combination of high magnetic-ordering temperature and short periodicity in terms of a quantum phase transition where excess-cobalt spins are coupled through the host matrix.

5.
Sci Adv ; 5(11): eaax6976, 2019 11.
Article in English | MEDLINE | ID: mdl-31701005

ABSTRACT

The synthesis of support materials with suitable coordination sites and confined structures for the controlled growth of ultrasmall metal nanoparticles is of great importance in heterogeneous catalysis. Here, by rational design of a cross-linked ß-cyclodextrin polymer network (CPN), various metal nanoparticles (palladium, silver, platinum, gold, and rhodium) of subnanometer size (<1 nm) and narrow size distribution are formed via a mild and facile procedure. The presence of the metal coordination sites and the network structure are key to the successful synthesis and stabilization of the ultrasmall metal nanoparticles. The as-prepared CPN, loaded with palladium nanoparticles, is used as a heterogeneous catalyst and shows outstanding catalytic performance in the hydrogenation of nitro compounds and Suzuki-Miyaura coupling reaction under mild conditions. The CPN support works synergistically with the metal nanoparticles, achieving high catalytic activity and selectivity. In addition, the catalytic activity of the formed catalyst is controllable.

6.
Adv Mater ; 30(51): e1803477, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30368920

ABSTRACT

The development of stable and efficient hydrogen evolution reaction (HER) catalysts is essential for the production of hydrogen as a clean energy resource. A combination of experiment and theory demonstrates that the normally inert basal planes of 2D layers of MoS2 can be made highly catalytically active for the HER when alloyed with rhenium (Re). The presence of Re at the ≈50% level converts the material to a stable distorted tetragonal (DT) structure that shows enhanced HER activity as compared to most of the MoS2 -based catalysts reported in the literature. More importantly, this new alloy catalyst shows much better stability over time and cycling than lithiated 1T-MoS2 . Density functional theory calculations find that the role of Re is only to stabilize the DT structure, while catalysis occurs primarily in local Mo-rich DT configurations, where the HER catalytic activity is very close to that in Pt. The study provides a new strategy to improve the overall HER performance of MoS2 -based materials via chemical doping.

7.
Arch Pharm (Weinheim) ; 350(3-4)2017 Apr.
Article in English | MEDLINE | ID: mdl-28317151

ABSTRACT

In view of potent kinase inhibitors for the treatment of myriad human disorders, we synthesized some structurally variant amide/cyclic amide derivatives based on pyridylpyrimidinylaminophenyl amine, the key pharmacophore of the kinase inhibitor drug molecule, imatinib, and evaluated their kinase inhibition potency. Among the various synthesized amides, compound 20, a cyclic amide/pyridin-2(1H)-one derivative, exhibited an IC50 value comparable to that of the drug imatinib against c-Src kinase, and another compound (14) containing a 2-((4-methyl-2-oxo-2H-chromen-6-yl)oxy)acetamide demonstrated an IC50 value of 8.39 µM. Furthermore, the constitution of the cyclic amide derivative was confirmed by the single-crystal X-ray diffraction technique. These results may serve as a gateway for developing novel next-generation kinase inhibitors.


Subject(s)
Amides/pharmacology , Drug Design , Protein Kinase Inhibitors/pharmacology , src-Family Kinases/antagonists & inhibitors , Amides/chemical synthesis , Amides/chemistry , CSK Tyrosine-Protein Kinase , Dose-Response Relationship, Drug , Humans , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Structure-Activity Relationship , src-Family Kinases/metabolism
8.
ACS Omega ; 2(8): 4480-4487, 2017 Aug 31.
Article in English | MEDLINE | ID: mdl-31457740

ABSTRACT

Magnetic nanoparticles are widely used in biomedical and oil-well applications in aqueous, often harsh environments. The pursuit for high-saturation magnetization together with high stability of the molecular coating that prevents agglomeration and oxidation remains an active research area. Here, we report a detailed analysis of the criteria for the stability of molecular coatings in aqueous environments along with extensive first-principles calculations for magnetite, which has been widely used, and cementite, a promising emerging candidate. A key result is that the simple binding energies of molecules cannot be used as a definitive indicator of relative stability in a liquid environment. Instead, we find that H+ ions and water molecules facilitate the desorption of molecules from the surface. We further find that, because of differences in the geometry of crystal structures, molecules generally form stronger bonds on cementite surfaces than they do on magnetite surfaces. The net result is that molecular coatings of cementite nanoparticles are more stable. This feature, together with the better magnetic properties, makes cementite nanoparticles a promising candidate for biomedical and oil-well applications.

9.
Nano Lett ; 16(2): 1132-7, 2016 Feb 10.
Article in English | MEDLINE | ID: mdl-26756914

ABSTRACT

Mn-based silicides are fascinating due to their exotic spin textures and unique crystal structures, but the low magnetic ordering temperatures and/or small magnetic moments of bulk alloys are major impediments to their use in practical applications. In sharp contrast to bulk Mn5Si3, which is paramagnetic at room temperature and exhibits low-temperature antiferromagnetic ordering, we show ferromagnetic ordering in Mn5Si3 nanoparticles with a high Curie temperature (Tc ≈ 590 K). The Mn5Si3 nanoparticles have an average size of 8.6 nm and also exhibit large saturation magnetic polarizations (Js = 10.1 kG at 300 K and 12.4 kG at 3 K) and appreciable magnetocrystalline anisotropy constants (K1 = 6.2 Mergs/cm(3) at 300 K and at 12.8 Mergs/cm(3) at 3 K). The drastic change of the magnetic ordering and properties in the nanoparticles are attributed to low-dimensional and quantum-confinement effects, evident from first-principle density-functional-theory calculations.

10.
J Phys Condens Matter ; 28(6): 064002, 2016 Feb 17.
Article in English | MEDLINE | ID: mdl-26794410

ABSTRACT

Density-functional theory is used to investigate the phase-segregation behavior of two-dimensional transition-metal dichalcogenides, which are of current interest as beyond-graphene materials for optoelectronic and spintronic applications. Our focus is on the behavior of W1-x V x Se2 monolayers, whose end members are semiconducting WSe2 and ferromagnetic VSe2. The energetics favors phase segregation, but the spinodal decomposition temperature is rather low, about 420 K. The addition of V leads to a transition from a nonmagnetic semiconductor to a metallic ferromagnet, with a ferromagnetic moment of about 1.0 µ B per V atom. The transition is caused by a p-type doping mechanism, which shifts the Fermi level into the valence band. The finite-temperature structure and magnetism of the diselenide systems are discussed in terms of Onsager-type critical fluctuations and Bruggeman effective-medium behavior.

11.
Curr Top Med Chem ; 14(22): 2552-75, 2014.
Article in English | MEDLINE | ID: mdl-25478881

ABSTRACT

Chromones (1-benzopyran-4-ones) are natural occurring compounds present in representative amounts in a normal human diet and are associated with interesting physiological activities such as antiinflammatory, antidiabetic, antitumor, anticancer etc. These biological activities are thought to be related to the antioxidant properties of chromones i.e. to neutralize active oxygen and to cut off free radicals processes that can delay or inhibit cell impairment which leads to various diseases. In this review, we have summarized the literature reports published in about 70 research articles during the period January 2004 to March 2014 on more than 400 naturally as well as the synthetically derived chromone derivatives having antioxidant potential. The literature reports suggest that the double bond, a carbonyl group of chromone and 3´,4´-dihydroxy group (catechol) in ring B along with the C-3 and C-5 hydroxyl groups are important for radical scavenging activity. In turn, a decrease in the radical scavenging potential has been observed upon methylation / glycosylation of the hydroxyl groups on chromone nucleus.


Subject(s)
Chromones/chemistry , Free Radical Scavengers/chemistry , Humans
12.
Sci Rep ; 4: 6265, 2014 Sep 02.
Article in English | MEDLINE | ID: mdl-25179756

ABSTRACT

Nanoscience has been one of the outstanding driving forces in technology recently, arguably more so in magnetism than in any other branch of science and technology. Due to nanoscale bit size, a single computer hard disk is now able to store the text of 3,000,000 average-size books, and today's high-performance permanent magnets--found in hybrid cars, wind turbines, and disk drives--are nanostructured to a large degree. The nanostructures ideally are designed from Co- and Fe-rich building blocks without critical rare-earth elements, and often are required to exhibit high coercivity and magnetization at elevated temperatures of typically up to 180 °C for many important permanent-magnet applications. Here we achieve this goal in exchange-coupled hard-soft composite films by effective nanostructuring of high-anisotropy HfCo7 nanoparticles with a high-magnetization Fe65Co35 phase. An analysis based on a model structure shows that the soft-phase addition improves the performance of the hard-magnetic material by mitigating Brown's paradox in magnetism, a substantial reduction of coercivity from the anisotropy field. The nanostructures exhibit a high room-temperature energy product of about 20.3 MGOe (161.5 kJ/m(3)), which is a record for a rare earth- or Pt-free magnetic material and retain values as high as 17.1 MGOe (136.1 kJ/m(3)) at 180°C.

13.
ACS Nano ; 8(8): 8113-20, 2014 Aug 26.
Article in English | MEDLINE | ID: mdl-25010729

ABSTRACT

Formation of chemically ordered compounds of Fe and Au is inhibited in bulk materials due to their limited mutual solubility. However, here we report the formation of chemically ordered L12-type Fe3Au and FeAu3 compounds in Fe-Au sub-10 nm nanoparticles, suggesting that they are equilibrium structures in size-constrained systems. The stability of these L12-ordered Fe3Au and FeAu3 compounds along with a previously discovered L10-ordered FeAu has been explained by a size-dependent equilibrium thermodynamic model. Furthermore, the spin ordering of these three compounds has been computed using ab initio first-principle calculations. All ordered compounds exhibit a substantial magnetization at room temperature. The Fe3Au had a high saturation magnetization of about 143.6 emu/g with a ferromagnetic spin structure. The FeAu3 nanoparticles displayed a low saturation magnetization of about 11 emu/g. This suggests a antiferromagnetic spin structure, with the net magnetization arising from uncompensated surface spins. First-principle calculations using the Vienna ab initio simulation package (VASP) indicate that ferromagnetic ordering is energetically most stable in Fe3Au, while antiferromagnetic order is predicted in FeAu and FeAu3, consistent with the experimental results.

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