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Garrison Gibbons opublikował 5 miesięcy, 2 tygodnie temu
(PsycInfo Database Record (c) 2020 APA, all rights reserved).OBJECTIVES Several studies have documented the negative impact of microaggressions on anxiety among Black individuals. However, few investigations have examined the impact of microaggressions on Black college students’ worries about their future employment and potential moderating factors. We examined whether there would be an association between microaggressions and worries about future employment. Furthermore, both social support and academic achievement (measured by grade point average) were purported to moderate this association. METHOD Secondary data analysis was used, with the study sample consisting of Black college students (n = 225) from a predominately White institution. Participants had a mean age of 20.43 years (SD = 1.79), with females comprising 74.80% of the sample. RESULTS Results revealed that social support buffered the effect of microaggressions for low-achieving students, while a buffering effect of social support was not found for high-achieving students. CONCLUSIONS Perceived social support offers some protection against the exposure of racial microaggressions, although high-achieving Black college students (the most vulnerable to potential isolation and academic pressure) may not benefit from overall social support. (PsycInfo Database Record (c) 2020 APA, all rights reserved).Spatial control of surface functionalization and interactions is essential for microarray-based analysis. This study reports the fabrication of two-dimensional molecular films with site-specific functionalities, forming microarrays at discrete locations. Arrays of microsized gold disks were produced on a silicate membrane using microfabrication. On these arrays, orthogonal self-assembly of molecules was performed that can specifically bind to gold or silicate. The gold array elements were functionalized with a range of alkanethiols and the silicate with polymeric poly-l-lysine-grafted-poly(ethylene glycol) (PLL-PEG). The surface functionalization on the gold disk array and the surrounding substrate was characterized at each step using X-ray photoelectron spectroscopy (XPS) to show that alkanethiols are specifically attached to the gold. PLL-PEG was used to provide resistance against nonspecific protein and cell adsorption and attached exclusively to the silicate. The effectiveness of the surface chemistry was validated by the selective self-assembly of a gold nanoparticle monolayer array on the gold regions. In a more sophisticated example, selective adhesion of MCF-7 cells to anti-EpCAM antibody modified gold areas of the gold-silicate surface was demonstrated to give a cell microarray. This study provides a general approach to fabricate chemical patterns on silicon-based devices with the convergence of microfabrication and material-specific surface modification, which may be useful to expand the functionalities and potential applications for patterned biomolecular films. Importantly, the ability to pattern surfaces with different surface chemistries is not limited to planar surfaces using this orthogonal surface-coupling approach.In this work, a separator modified by composite material of graphite fluoride nanosheets and poly(vinylidene difluoride) (GFNs-PVDF) is fabricated to in-situ construct a protective layer on Li metal anodes. The much-improved mechanical properties of this organic/inorganic protecting layer ensure efficient restriction on the growth of Li dendrites. The LiF and graphene nanosheets generated by the reaction of GFNs with lithium metal can not only provide fast transport channels for Li ions but also protect the Li metal anode from continuous corrosion of electrolytes. In addition, GFNs’ lithiophilic nature guarantees the uniform Li nucleation site and perfect contact between li metal and the protecting layer without void space, leading to a low interfacial impedance and layer-by-layer lithium deposition. Together with the scalable method and cheap raw materials, this strategy provides new insights toward practical applications of Li metal batteries.Spin waves can be used as information carriers with low energy dissipation. The excitation and propagation of spin waves along reconfigurable magnonic circuits is the subject of much interest in the field of magnonic applications. Here we experimentally demonstrate an effective excitation of spin waves in reconfigurable magnetic textures at frequencies as high as 15 GHz and wavelengths as short as 80 nm from Ni80Fe20 (Py) nanodisk-film hybrid structures. Most importantly, we demonstrate these spin wave modes, which were previously confined within a nanodisk, can now couple to and propagate along a nanochannel formed by magnetic domain walls at zero magnetic bias field. The tunable high-frequency, short-wavelength, and propagating spin waves may play a vital role in energy efficient and programmable magnonic devices at the nanoscale.Understanding of the structure-function relationships of natural protein channels remains a challenging task because of their unattainable physiological functions in terms of selectivity. To achieve this, a synthetic system of chemically modified channels has been constructed based on helical polymer scaffolds. Here, we report a type of positively charged channels in which multiple quaternary ammonium groups are covalently modified on the lumen surface of helical polymer while the helical conformation is intact. Compared to unmodified channels, the existence of multiple charged groups in the cavity not only makes the lumen size narrower but also essentially changes the channel properties without obstructing channel structure. Our study indicates that positively charged channels preferentially transport anions with size-dependent selectivity, whereas alkali metal ions are almost completely suppressed by electrostatic repulsion. As a consequence, a specific artificial channel with high Cl-/Na+ selectivity ratio of 411 is obtained.A simple iridium catalytic system was developed that allows for a variety of 2-borylthioanisoles to be easily synthesized via ortho-selective C-H borylation of thioanisole derivatives. Once introduced, boryl and methylthio groups were converted by palladium-catalyzed transformations. Density functional theory calculations revealed that weak interactions, such as hydrogen bonding between the C-H bond of the SCH3 group and the oxygen atom of the boryl ligand, control the ortho-selectivity.Spiroseoflosterol (1), a 7(8→9)-abeo-ergostane steroid with a unique spiro[4.5]decan-6-one system, was isolated from the fruiting bodies of Butyriboletus roseoflavus. Its structure was determined by interpretation of comprehensive spectroscopic, X-ray, and computational data. A plausible biogenetic pathway for spiroseoflosterol (1) was postulated based on a key semipinacol rearrangement. Compound 1 was cytotoxic to HepG2 and Huh7/S (sorafenib-resistant Huh7) with IC50 values of 9.1 and 6.2 μM, respectively.The remarkable biological activity of the dolastatin 10 structural modifications quinstatins and isoquinstatins prompted further investigation into drug hybrids containing biologically active isoquinoline moieties. In this study, the isoquinoline alkaloid emetine was selected as one of the structural domains of a hybrid molecule. That was accomplished by covalently bonding the Dov-Val-Dil-Dap peptide sequence of dolastatin 10 peptide at the N-2′ secondary amine of emetine. Three new hybrids were synthesized, 5, 9, and 10. Comparison of the biological activity of these new peptide-emetine analogues with emetine showed complete retention of activity for 5 and a 10-fold decrease for hybrids 9 and 10. The result was surprising, as the activity of emetine is usually lost or greatly reduced when substituted at the N-2′ position.The rotational spectrum of 1,3,5-trisilapentane was observed on a chirped-pulse Fourier transform microwave spectrometer and is reported. During assignment, multiple conformations of the molecule were identified in the molecular beam. Prior quantum-chemical calculations performed on the molecule show that the identified spectra correspond to the lowest three calculated energetic structures. These structures are of C2 (Conf.1), C2v (Conf.2), and C1 (Conf.3) symmetry, with relative energy ordering of Conf.1 less then Conf.3 less then Conf.2, which is in stark contrast to n-pentane and all known silicon-substituted n-pentane derivatives. This is found to most likely arise from the elongation of the Si-C bond and the size of the silicon atoms providing for the C2 and C1 structures relieving steric hindrance in comparison to that of the C2v. In the C2v and C1 conformers, splitting in the spectra due to internal rotation of the -SiH3 end groups of 1,3,5-trisilapentane was observed and determined. The C2v equivalent V3 values are 368.46(33) cm-1, and the C1V3 values are 347.78(21) and 360.18(88) cm-1, respectively. These barriers are compared to similar species in order to help verify their veracity and are determined to be accurate based on similar molecular silyl rotors.To clarify the odorants responsible for a rancid off-flavor in olive oils, first, the key aroma compounds in a premium extra virgin olive oil (PreOO1) were characterized by the sensomics approach and were then compared to those present in a certified rancid off-flavor olive oil (RanOO1) obtained from the International Olive Council (IOC). By application of an aroma extract dilution analysis, 46 odorants were detected and subsequently identified in PreOO1 and 35 odorants in RanOO1, respectively. After quantitation by stable isotope dilution assays, calculation of odor activity values (OAV; ratio of concentration to odor threshold) revealed only five odorants with OAVs > 10 in PreOO1, while 13 odorants showed OAVs > 500 in RanOO1 with hexanoic acid, (E,Z)-2,4-decadienal, octanal, hexanal, (E)-2-octenal, and (Z)-2-nonenal being among the most odor-active compounds. Thus, marker aroma compounds for this off-flavor type could be suggested. Additionally, based on the OAVs obtained, the overall aroma profiles of both oils were mimicked by aroma recombination experiments. As proof of concept, 16 marker odorants were quantitated in two additional extra virgin olive oils and in eight further olive oils eliciting a rancid off-flavor. Application of a principal component analysis (PCA) and a hierarchical cluster analysis successfully discriminated both categories of olive oils. In the twelve olive oils used, acetic acid showed the highest Pearson coefficient between the perceived intensity of the rancid defect and the odorant concentration. In particular, (E,Z)- and (E,E)-2,4-decadienal and (Z)-2-nonenal can be suggested as chemical markers for olive oil rancidity in combination with positive aroma markers, for example, acetaldehyde and (Z)-3-hexenal.Tomato chlorosis virus (ToCV) has caused great harm to the production of tomato worldwide. To develop efficient anti-ToCV agents, some novel 4(3H)-quinazolinone derivatives containing dithioacetal were designed and synthesized, and their anti-ToCV activities were evaluated by microscale thermophoresis (MST) using ToCV coat protein (ToCV-CP) as a new target. The results showed that some compounds had a strong binding capacity to ToCV-CP. In particular, compounds C5 and C22 have an excellent binding capacity to ToCV-CP, with binding constant values of 0.24 and 0.25 μM, respectively. Additionally, reduced ToCV-CP gene expression levels of 81.05 and 87.59% could be achieved when tomato was treated with compounds C5 and C22, respectively, which were obviously higher than the levels after ningnanmycin (NNM) treatment (43.88%) and lead compound Xiangcaoliusuobingmi (XCLSBM) treatment (63.56%). Therefore, this work indicates that 4(3H)-quinazolinone derivatives containing dithioacetal moiety can be used as novel anti-ToCV agents.