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1.
Nature ; 590(7844): 85-88, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33536647

RESUMO

The transplutonium elements (atomic numbers 95-103) are a group of metals that lie at the edge of the periodic table. As a result, the patterns and trends used to predict and control the physics and chemistry for transition metals, main-group elements and lanthanides are less applicable to transplutonium elements. Furthermore, understanding the properties of these heavy elements has been restricted by their scarcity and radioactivity. This is especially true for einsteinium (Es), the heaviest element on the periodic table that can currently be generated in quantities sufficient to enable classical macroscale studies1. Here we characterize a coordination complex of einsteinium, using less than 200 nanograms of 254Es (with half-life of 275.7(5) days), with an organic hydroxypyridinone-based chelating ligand. X-ray absorption spectroscopic and structural studies are used to determine the energy of the L3-edge and a bond distance of einsteinium. Photophysical measurements show antenna sensitization of EsIII luminescence; they also reveal a hypsochromic shift on metal complexation, which had not previously been observed in lower-atomic-number actinide elements. These findings are indicative of an intermediate spin-orbit coupling scheme in which j-j coupling (whereby single-electron orbital angular momentum and spin are first coupled to form a total angular momentum, j) prevails over Russell-Saunders coupling. Together with previous actinide complexation studies2, our results highlight the need to continue studying the unusual behaviour of the actinide elements, especially those that are scarce and short-lived.

2.
Nature ; 599(7885): 421-424, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34789902

RESUMO

Californium (Cf) is currently the heaviest element accessible above microgram quantities. Cf isotopes impose severe experimental challenges due to their scarcity and radiological hazards. Consequently, chemical secrets ranging from the accessibility of 5f/6d valence orbitals to engage in bonding, the role of spin-orbit coupling in electronic structure, and reactivity patterns compared to other f elements, remain locked. Organometallic molecules were foundational in elucidating periodicity and bonding trends across the periodic table1-3, with a twenty-first-century renaissance of organometallic thorium (Th) through plutonium (Pu) chemistry4-12, and to a smaller extent americium (Am)13, transforming chemical understanding. Yet, analogous curium (Cm) to Cf chemistry has lain dormant since the 1970s. Here, we revive air-/moisture-sensitive Cf chemistry through the synthesis and characterization of [Cf(C5Me4H)2Cl2K(OEt2)]n from two milligrams of 249Cf. This bent metallocene motif, not previously structurally authenticated beyond uranium (U)14,15, contains the first crystallographically characterized Cf-C bond. Analysis suggests the Cf-C bond is largely ionic with a small covalent contribution. Lowered Cf 5f orbital energy versus dysprosium (Dy) 4f in the colourless, isoelectronic and isostructural [Dy(C5Me4H)2Cl2K(OEt2)]n results in an orange Cf compound, contrasting with the light-green colour typically associated with Cf compounds16-22.

3.
Nano Lett ; 23(20): 9272-9279, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37811908

RESUMO

We present a novel method for fabricating highly customizable three-dimensional structures hosting quantum sensors based on nitrogen vacancy (NV) centers using two-photon polymerization. This approach overcomes challenges associated with structuring traditional single-crystal quantum sensing platforms and enables the creation of complex, fully three-dimensional, sensor assemblies with submicroscale resolutions (down to 400 nm) and large fields of view (>1 mm). By embedding NV center-containing nanoparticles in exemplary structures, we demonstrate high sensitivity optical sensing of temperature and magnetic fields at the microscale. Our work showcases the potential for integrating quantum sensors with advanced manufacturing techniques, facilitating the incorporation of sensors into existing microfluidic and electronic platforms, and opening new avenues for widespread utilization of quantum sensors in various applications.

4.
J Neural Transm (Vienna) ; 130(12): 1579-1599, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37391573

RESUMO

Methylphenidate (MPD) is a psychostimulant used to treat attention deficit hyperactivity disorder. MPD exerts its neurocognitive effects through increasing concentrations of dopamine (DA), norepinephrine (NE), and serotonin (5-HT) in the neuronal synapse. This study recorded from adult freely behaving rats a total of 1170 neurons, 403 from the ventral tegmental area (VTA), 409 from locus coeruleus (LC), and 356 from dorsal raphe (DR) nucleus, which are the main sources of DA, NE, and 5-HT to the mesocorticolimbic circuitry, respectively. Electrophysiological and behavioral activities were recorded simultaneously following acute and repetitive (chronic) saline or 0.6, 2.5, or 10.0 mg/kg MPD. The uniqueness of this study is the evaluation of neuronal activity based on the behavioral response to chronic MPD. Animals received daily saline or MPD administration on experimental days 1-6 (ED1-6), followed by a 3-day wash-out period, and then MPD rechallenge on ED10. Each chronic MPD dose elicits behavioral sensitization in some animals, while in others, behavioral tolerance. Neuronal excitation following chronic MPD was observed in brains areas of animals exhibiting behavioral sensitization, while neuronal attenuation following chronic MPD was observed in those animals expressing behavioral tolerance. DR neuronal activity was most affected in response to acute and chronic MPD administration and responded differently compared to the neurons recorded from VTA and LC neurons at all doses. This suggests that although not directly related, DR and 5-HT are involved in the acute and chronic effects of MPD in adult rats, but exhibit a different role in response to MPD.


Assuntos
Estimulantes do Sistema Nervoso Central , Metilfenidato , Ratos , Animais , Metilfenidato/farmacologia , Área Tegmentar Ventral , Núcleo Dorsal da Rafe , Locus Cerúleo , Serotonina/farmacologia , Ratos Sprague-Dawley , Relação Dose-Resposta a Droga , Estimulantes do Sistema Nervoso Central/farmacologia , Neurônios
5.
Inorg Chem ; 62(27): 10528-10538, 2023 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-37379331

RESUMO

Modern molten salt reactor design and the techniques of electrorefining spent nuclear fuels require a better understanding of the chemical and physical behavior of lanthanide/actinide ions with different oxidation states dissolved in various solvent salts. The molecular structures and dynamics that are driven by the short-range interactions between solute cations and anions and long-range solute and solvent cations are still unclear. In order to study the structural change of solute cations caused by different solvent salts, we performed first-principles molecular dynamics simulations in molten salts and extended X-ray absorption fine structure (EXAFS) measurements for the cooled molten salt samples to identify the local coordination environment of Eu2+ and Eu3+ ions in CaCl2, NaCl, and KCl. The simulations reveal that with the increasing polarizing the outer sphere cations from K+ to Na+ to Ca2+, the coordination number (CN) of Cl- in the first solvation shell increases from 5.6 (Eu2+) and 5.9 (Eu3+) in KCl to 6.9 (Eu2+) and 7.0 (Eu3+) in CaCl2. This coordination change is validated by the EXAFS measurements, in which the CN of Cl- around Eu increases from 5 in KCl to 7 in CaCl2. Our simulation shows that the fewer Cl- ions coordinated to Eu leads to a more rigid first coordination shell with longer lifetime. Furthermore, the diffusivities of Eu2+/Eu3+ are related to the rigidity of their first coordination shell of Cl-: the more rigid the first coordination shell is, the slower the solute cations diffuse.

6.
J Appl Microbiol ; 134(8)2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37505452

RESUMO

AIMS: This study aimed to evaluate the effects of storage and different temperatures on the antibacterial activity and physicochemical characteristics of several types of honey. METHODS AND RESULTS: Honeys stored for 16 weeks at 37 and 45°C showed significant declines in antibacterial activity determined by minimum inhibitory concentrations, the loss of hydrogen peroxide, decreases in honey pH, and increases in honey colour, with changes most pronounced at 45°C. In contrast, honeys stored for 16 weeks at ambient (∼22°C) and cold (4, -20, and -80°C) temperatures showed only minor changes. In a second set of 12 honeys stored for 16-32 months at ambient temperature and then 4°C, honeys showed minor changes in antibacterial activity, increases in colour, and decreases in pH. For a third set of 17 honeys stored for five years at ambient temperature, the honeys showed almost complete loss of hydrogen peroxide and were all significantly darker in colour, but showed varied changes in antibacterial activity. CONCLUSIONS: Heat was detrimental to the antibacterial activity of honeys, as was long-term storage at ambient temperatures for some honeys but not others.


Assuntos
Mel , Peróxido de Hidrogênio , Peróxido de Hidrogênio/farmacologia , Mel/análise , Austrália , Temperatura , Cor , Testes de Sensibilidade Microbiana , Antibacterianos/farmacologia , Antibacterianos/química
7.
Int J Mol Sci ; 24(23)2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-38068951

RESUMO

Methylphenidate (MPD), known as Ritalin, is a psychostimulant used to treat children, adults, and the elderly. MPD exerts its effects through increasing concentrations of dopamine (DA), norepinephrine (NE), and serotonin (5-HT) in the synaptic cleft. Concomitant behavioral and neuronal recording from the ventral tegmental area (VTA), locus coeruleus (LC), and from the dorsal raphe (DR) nucleus, which are the sources of DA, NE, and 5-HT to the mesocorticolimbic circuit, were investigated following acute and repetitive (chronic) saline, 0.6, 2.5, or 10.0 mg/kg MPD. Animals received daily saline or MPD administration on experimental days 1 to 6 (ED1-6), followed by a 3-day washout period and MPD rechallenge on ED10. Each chronic MPD dose elicits behavioral sensitization in some animals while inducing behavioral tolerance in others. The uniqueness of this study is in the evaluation of neuronal activity based on the behavioral response to chronic MPD. Neuronal excitation was observed mainly in brain areas of animals exhibiting behavioral sensitization, while neuronal attenuation following chronic MPD was observed in animals expressing behavioral tolerance. Different ratios of excitatory/inhibitory neuronal responses were obtained from the VTA, LC, or DR following chronic MPD. Thus, each brain area responds differently to each MPD dose used, suggesting that DA, NE, and 5-HT in the VTA, LC, and DR exert different effects.


Assuntos
Metilfenidato , Humanos , Criança , Ratos , Animais , Idoso , Metilfenidato/farmacologia , Serotonina/farmacologia , Área Tegmentar Ventral , Dopamina/farmacologia , Núcleo Dorsal da Rafe , Locus Cerúleo , Norepinefrina/farmacologia , Ratos Sprague-Dawley
8.
Int J Mol Sci ; 24(18)2023 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-37762483

RESUMO

Cotton (Gossypium spp.) is the primary source of natural textile fiber in the U.S. and a major crop in the Southeastern U.S. Despite constant efforts to increase the cotton fiber yield, the yield gain has stagnated. Therefore, we undertook a novel approach to improve the cotton fiber yield by altering its growth habit from perennial to annual. In this effort, we identified genotypes with high-expression alleles of five floral induction and meristem identity genes (FT, SOC1, FUL, LFY, and AP1) from an Upland cotton mini-core collection and crossed them in various combinations to develop cotton lines with annual growth habit, optimal flowering time, and enhanced productivity. To facilitate the characterization of genotypes with the desired combinations of stacked alleles, we identified molecular markers associated with the gene expression traits via genome-wide association analysis using a 63 K SNP Array. Over 14,500 SNPs showed polymorphism and were used for association analysis. A total of 396 markers showed associations with expression traits. Of these 396 markers, 159 were mapped to genes, 50 to untranslated regions, and 187 to random genomic regions. Biased genomic distribution of associated markers was observed where more trait-associated markers mapped to the cotton D sub-genome. Many quantitative trait loci coincided at specific genomic regions. This observation has implications as these traits could be bred together. The analysis also allowed the identification of candidate regulators of the expression patterns of these floral induction and meristem identity genes whose functions will be validated.

9.
Biochemistry ; 61(5): 319-326, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-35129961

RESUMO

Coiled coils are among the most abundant tertiary and quaternary structures found in proteins. A growing body of evidence suggests that long-range synergistic interactions among solvent-exposed residues can contribute substantially to coiled-coil conformational stability, but our understanding of the key sequence and structural prerequisites of this effect is still developing. Here, we show that the strength of synergistic interaction involving a b-position Glu (i), an f-position Tyr (i + 4), and a c-position Lys (i + 8) depends on the identity of the f-position residue, the length and stability of the coiled coil, and its oligomerization stoichiometry/surface accessibility. Combined with previous observations, these results map out predictable sequence- and structure-based criteria for enhancing coiled-coil stability by up to -0.58 kcal/mol per monomer (or -2.32 kcal/mol per coiled-coil tetramer). Our observations expand the available tools for enhancing coiled coil stability by sequence variation at solvent-exposed b-, c-, and f-positions and suggest the need to exercise care in the choice of substitutions at these positions for application-specific purposes.


Assuntos
Estrutura Secundária de Proteína , Sequência de Aminoácidos , Dicroísmo Circular , Desnaturação Proteica , Solventes
10.
Inorg Chem ; 61(33): 12948-12953, 2022 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-35939562

RESUMO

Historic perspectives describing f-elements as being redox "inactive" are fading. Researchers continue to discover new oxidation states that are not as inaccessible as once assumed for actinides and lanthanides. Inspired by those contributions, we studied americium(III) oxidation in aqueous media under air using NaBiO3(s). We identified selective oxidation of Am3+(aq) to AmO22+(aq) or AmO21+(aq) could be achieved by changing the aqueous matrix identity. AmO22+(aq) formed in H3PO4(aq) (1 M) and AmO21+(aq) formed in dilute HCl(aq) (0.1 M). These americyl products were stable for weeks in solution. Also included is a method to recover 243Am from the americium and bismuth mixtures generated during these studies.

11.
Biochemistry ; 60(26): 2064-2070, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34137579

RESUMO

Here we show that an NH-π interaction between a highly conserved Asn and a nearby Trp stabilizes the WW domain of the human protein Pin1. The strength of this NH-π interaction depends on the structure of the arene, with NH-π interactions involving Trp or naphthylalanine being substantially more stabilizing than those involving Tyr or Phe. Calculations suggest arene size and polarizability are key structural determinants of NH-π interaction strength. Methylation or PEGylation of the Asn side-chain amide nitrogen each strengthens the associated NH-π interaction, though likely for different reasons. We hypothesize that methylation introduces steric clashes that destabilize conformations in which the NH-π interaction is not possible, whereas PEGylation strengthens the NH-π interaction via localized desolvation of the protein surface.


Assuntos
Asparagina/química , Ligação de Hidrogênio/efeitos dos fármacos , Peptidilprolil Isomerase de Interação com NIMA/química , Polietilenoglicóis/química , Triptofano/química , Domínios WW/efeitos dos fármacos , Sequência de Aminoácidos , Humanos , Metilação , Modelos Moleculares , Mutação , Peptidilprolil Isomerase de Interação com NIMA/genética , Conformação Proteica , Termodinâmica , Domínios WW/genética
12.
Langmuir ; 37(30): 9222-9231, 2021 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-34279965

RESUMO

Functionalization of diamond surfaces with TEMPO and other surface paramagnetic species represents one approach to the implementation of novel chemical detection schemes that make use of shallow quantum color defects such as silicon-vacancy (SiV) and nitrogen-vacancy (NV) centers. Yet, prior approaches to quantum-based chemical sensing have been hampered by the absence of high-quality surface functionalization schemes for linking radicals to diamond surfaces. Here, we demonstrate a highly controlled approach to the functionalization of diamond surfaces with carboxylic acid groups via all-carbon tethers of different lengths, followed by covalent chemistry to yield high-quality, TEMPO-modified surfaces. Our studies yield estimated surface densities of 4-amino-TEMPO of approximately 1.4 molecules nm-2 on nanodiamond (varying with molecular linker length) and 3.3 molecules nm-2 on planar diamond. These values are higher than those reported previously using other functionalization methods. The ζ-potential of nanodiamonds was used to track reaction progress and elucidate the regioselectivity of the reaction between ethenyl and carboxylate groups and surface radicals.

13.
J Am Chem Soc ; 141(43): 17370-17381, 2019 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-31584807

RESUMO

The reductive cleavage of aryl ether linkages is a key step in the disassembly of lignin to its monolignol components, where selectivity is determined by the kinetics of multiple parallel and consecutive liquid-phase reactions. Triphasic hydrogenolysis of 13C-labeled benzyl phenyl ether (BPE, a model compound for the major ß-O-4 linkage in lignin), catalyzed by Ni/γ-Al2O3, was observed directly at elevated temperatures (150-175 °C) and pressures (79-89 bar) using operando magic-angle spinning NMR spectroscopy. Liquid-vapor partitioning in the NMR rotor was quantified using the 13C NMR resonances for the 2-propanol solvent, whose chemical shifts report on the internal reactor temperature. At 170 °C, BPE is converted to toluene and phenol with k1 = 0.17 s-1 gcat-1 and an apparent activation barrier of (80 ± 8) kJ mol-1. Subsequent phenol hydrogenation occurs much more slowly (k2 = 0.0052 s-1 gcat-1 at 170-175 °C), such that cyclohexanol formation is significant only at higher temperatures. Toluene is stable under these reaction conditions, but its methyl group undergoes facile H/D exchange (k3 = 0.046 s-1 gcat-1 at 175 °C). While the source of the reducing equivalents for both hydrogenolysis and hydrogenation is exclusively H2/D2(g) rather than the alcohol solvent at these temperatures, the initial isotopic composition of adsorbed H/D on the catalyst surface is principally determined by the solvent isotopic composition (2-PrOH/D). All reactions are preceded by a pronounced induction period associated with catalyst activation. In air, Ni nanoparticles are passivated by a surface oxide monolayer, whose removal under H2 proceeds with an apparent activation barrier of (72 ± 13) kJ mol-1. The operando NMR spectra provide molecularly specific, time-resolved information about the multiple simultaneous and sequential processes as they occur at the solid-liquid interface.

14.
Inorg Chem ; 58(13): 8739-8749, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31198031

RESUMO

Thiolates are a widely used ligand class for the stabilization of M(0)-containing gold and silver nanoclusters. Curiously, though, very few thiolate-stabilized Cu nanoclusters are known. Herein, we report an examination of the reactivity of RSH (R = CH2CH2Ph, n-Bu, n-C12H25) with Cu2+ under anhydrous conditions. These reactions result in the formation of fluorescent "Atlas-sphere"-type copper thiolate nanoclusters, including [Cu12(SR')6Cl12][(Cu(R'SH))6] (2, R' = nBu) and [H(THF)2]2[Cu17(SR'')6Cl13(THF)2(R''SH)3] (3, R'' = CH2CH2Ph), which were characterized by X-ray crystallography, electrospray ionization mass spectrometry, NMR spectroscopy, as well as X-ray absorption near-edge structure and extended X-ray absorption fine structure (EXAFS) spectroscopies. Consistent with our X-ray crystallographic results, the edge energies of 2 and 3 suggest they are constructed exclusively with Cu(I) ions. Similarly, EXAFS of 2 and 3 reveals long Cu-Cu pathlengths, which is also consistent with their X-ray crystal structures. Given these results, as well as past work on Cu2+/thiol reactivity, we suggest that Cu(0) is unlikely to be formed by the reaction of Cu2+ with a thiol and that previous reports of Cu(0)-containing nanoclusters synthesized by reaction of Cu2+ with thiols are likely erroneous.

15.
Hosp Pharm ; 54(3): 175-179, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31205328

RESUMO

Purpose: The United States has seen an increased consumption of carbapenem antibiotics in recent years. The increased utilization of these agents has potential negative consequences, including the increasing incidence of carbapenem-resistant Enterobacteriaceae. Reasons for the rise in carbapenem use among providers in acute care hospitals are not well elucidated in literature. The objectives of this study were to identify factors that influence empiric carbapenem use among providers in a single academic medical center, and to assess therapeutic knowledge pertaining to carbapenem use. Methods: A cross-sectional, single-center, 9-item electronic research survey was developed independently and validated by an infectious diseases pharmacist and infectious diseases physician. The survey was distributed to email accounts of providers at a single academic medical center. Demographic data, factors affecting carbapenem prescription, and baseline therapeutic knowledge were assessed. Results: Ninety-five of 416 providers responded to the survey (response rate of 22.8%). Respondents were well distributed across all levels of training with primary roles in internal medicine and surgery. The most important factors influencing empiric carbapenem use were suspected pathogens at the site of infection, drug allergies, history of multidrug resistant organisms, severity of illness, type of infection, and local resistance rates. A recommendation from a pharmacist was selected as the most likely factor for deterring carbapenem use. Misconceptions pertaining to penicillin drug allergy and beta-lactam cross reactivity, knowledge of local resistance rates according to the institutional antibiogram, and comparative efficacy data for carbapenems were apparent across all levels of training. Conclusions: Provider misconceptions regarding several factors appear to contribute to unnecessary use of carbapenems. An opportunity exists for hospital pharmacists to improve the prescribing patterns of carbapenems by correcting provider misconceptions through education.

16.
J Am Chem Soc ; 140(1): 394-400, 2018 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-29211459

RESUMO

The development of atomically precise nanoclusters (APNCs) protected by organometallic ligands, such as acetylides and hydrides, is an emerging area of nanoscience. In principle, these organometallic APNCs should not require harsh pretreatment for activation toward catalysis, such as calcination, which can lead to sintering. Herein, we report the synthesis of the mixed-valent organometallic copper APNC, [Cu20(CCPh)12(OAc)6)] (1), via reduction of Cu(OAc) with Ph2SiH2 in the presence of phenylacetylene. This cluster is a rare example of a two-electron copper superatom, and the first to feature a tetrahedral [Cu4]2+ core, which is a unique "kernel" for a Cu-only superatom. Complex 1 can be readily immobilized on dry, partially dehydroxylated silica, a process that cleanly results in release of 1 equiv of phenylacetylene per Cu20 cluster. Cu K-edge EXAFS confirms that the immobilized cluster 2 is structurally similar to 1. In addition, both 1 and 2 are effective catalysts for [3+2] cycloaddition reactions between alkynes and azides (i.e., "Click" reactions) at room temperature. Significantly, neither cluster requires any pretreatment for activation toward catalysis. Moreover, EXAFS analysis of 2 after catalysis demonstrates that the cluster undergoes no major structural or nuclearity changes during the reaction, consistent with our observation that supported cluster 2 is more stable than unsupported cluster 1 under "Click" reaction conditions.


Assuntos
Química Click , Cobre/química , Nanoestruturas/química , Compostos Organometálicos/síntese química , Dióxido de Silício/química , Reação de Cicloadição , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/química
17.
J Am Chem Soc ; 140(30): 9458-9465, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29986130

RESUMO

Uridine diphosphate N-acetyl muramic acid (UDP NAM) is a critical intermediate in bacterial peptidoglycan (PG) biosynthesis. As the primary source of muramic acid that shapes the PG backbone, modifications installed at the UDP NAM intermediate can be used to selectively tag and manipulate this polymer via metabolic incorporation. However, synthetic and purification strategies to access large quantities of these PG building blocks, as well as their derivatives, are challenging. A robust chemoenzymatic synthesis was developed using an expanded NAM library to produce a variety of 2 -N-functionalized UDP NAMs. In addition, a synthetic strategy to access bio-orthogonal 3-lactic acid NAM derivatives was developed. The chemoenzymatic UDP synthesis revealed that the bacterial cell wall recycling enzymes MurNAc/GlcNAc anomeric kinase (AmgK) and NAM α-1 phosphate uridylyl transferase (MurU) were permissive to permutations at the two and three positions of the sugar donor. We further explored the utility of these derivatives in the fluorescent labeling of both Gram (-) and Gram (+) PG in whole cells using a variety of bio-orthogonal chemistries including the tetrazine ligation. This report allows for rapid and scalable access to a variety of functionalized NAMs and UDP NAMs, which now can be used in tandem with other complementary bio-orthogonal labeling strategies to address fundamental questions surrounding PG's role in immunology and microbiology.


Assuntos
Parede Celular/metabolismo , Peptidoglicano/biossíntese , Uridina Difosfato Ácido N-Acetilmurâmico/análogos & derivados , Uridina Difosfato Ácido N-Acetilmurâmico/metabolismo , Bacillus subtilis/metabolismo , Escherichia coli/enzimologia , Escherichia coli/metabolismo , Lactatos/síntese química , Lactobacillus acidophilus/metabolismo , Estrutura Molecular , Nucleotidiltransferases/química , Proteínas Quinases/química , Staphylococcus aureus/metabolismo , Especificidade por Substrato , Uridina Difosfato Ácido N-Acetilmurâmico/síntese química
18.
J Couns Psychol ; 64(6): 724-738, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28541058

RESUMO

Using multigroup structural equation modeling in a large sample of online-survey respondents (N = 6,744), the present study examined the reliability and dimensionality of the Male Role Norms Inventory-Short Form (MRNI-SF), a popular measurement of traditional masculinity ideology (TMI), and also tested measurement invariance between individuals that do and do not fit the White heterosexual male TMI reference group. Results indicated that (a) it is appropriate to model the MRNI-SF using either a bifactor or unidimensional model but not a second-order model, (b) the raw MRNI-SF total score is a suitable measure of the general TMI construct, (c) the raw self-reliance through mechanical skills and negativity toward sexual minorities subscale scores may be appropriate measures of their respective specific factors (akin to subscale factors), and (d) SEM or ipsatizing procedures should be used to model the 5 other specific factors, given the insufficient model-based reliability of their raw subscale scores. When comparing men to women, White men to Black and Asian men, and gay men to heterosexual men, the MRNI-SF demonstrated configural invariance and at least partial metric invariance (i.e., measured similar constructs). However, scalar and residuals invariance were only supported for Asian men compared to White men. Taken together, these findings suggest that a general TMI factor of the MRNI-SF is best represented by a bifactor model, even in individuals that do not fit the White heterosexual male TMI reference group, but the instrument may be tapping somewhat different constructs in women, Black men, and gay men. (PsycINFO Database Record


Assuntos
Negro ou Afro-Americano/psicologia , Masculinidade , Minorias Sexuais e de Gênero/psicologia , Inquéritos e Questionários/normas , Adulto , Feminino , Identidade de Gênero , Heterossexualidade/psicologia , Humanos , Masculino , Reprodutibilidade dos Testes , População Branca/psicologia
19.
J Neuroinflammation ; 13(1): 260, 2016 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-27716334

RESUMO

Spinal cord injury (SCI) is a devastating event that results in significant physical disabilities for affected individuals. Apart from local injury within the spinal cord, SCI patients develop a variety of complications characterized by multiple organ dysfunction or failure. These disorders, such as neurogenic pain, depression, lung injury, cardiovascular disease, liver damage, kidney dysfunction, urinary tract infection, and increased susceptibility to pathogen infection, are common in injured patients, hinder functional recovery, and can even be life threatening. Multiple lines of evidence point to pathological connections emanating from the injured spinal cord, post-injury systemic inflammation, and immune suppression as important multifactorial mechanisms underlying post-SCI complications. SCI triggers systemic inflammatory responses marked by increased circulation of immune cells and pro-inflammatory mediators, which result in the infiltration of inflammatory cells into secondary organs and persistence of an inflammatory microenvironment that contributes to organ dysfunction. SCI also induces immune deficiency through immune organ dysfunction, resulting in impaired responsiveness to pathogen infection. In this review, we summarize current evidence demonstrating the relevance of inflammatory conditions and immune suppression in several complications frequently seen following SCI. In addition, we highlight the potential pathways by which inflammatory and immune cues contribute to multiple organ failure and dysfunction and discuss current anti-inflammatory approaches used to alleviate post-SCI complications. A comprehensive review of this literature may provide new insights into therapeutic strategies against complications after SCI by targeting systemic inflammation.


Assuntos
Doenças do Sistema Imunitário/etiologia , Doenças do Sistema Imunitário/patologia , Traumatismos da Medula Espinal/complicações , Animais , Doenças Cardiovasculares/etiologia , Gastroenteropatias/etiologia , Humanos , Nefropatias/etiologia , Hepatopatias/etiologia , Doenças Musculares/etiologia
20.
Langmuir ; 32(39): 10113-10119, 2016 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-27607195

RESUMO

Surface patterns over multiple length scales are known to influence various biological processes. Here we report the synthesis and characterization of new, two-component xerogel thin films derived from carboxyethylsilanetriol (COE) and tetraethoxysilane (TEOS). Atomic force microscopy (AFM) reveals films surface with branched and hyper branched architectures that are ∼2 to 30 µm in diameter, that extend ∼3 to 1300 nm above the film base plane with surface densities that range from 2 to 77% surface area coverage. Colocalized AFM and Raman spectroscopy show that these branched structures are COE-rich domains, which are slightly stiffer (as shown from phase AFM imaging) and exhibit lower capacitive force in comparison with film base plane. Raman mapping reveals there are also discrete domains (≤300 nm in diameter) that are rich in COE dimers and densified TEOS, which do not appear to correspond with any surface structure seen by AFM.

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