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1.
J Pers ; 91(1): 134-149, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-35837853

RESUMO

OBJECTIVE: This psychobiography analyzes the life of Khali Sweeney from Detroit's Downtown Boxing Gym to understand his motivation for and methods as a social change agent. In doing so, the project also considers how to prepare the next generation of youth development leaders as social change agents. METHOD: We conducted a nine-step psychobiography based on recommendations from established psychobiographical methods. Using a team-based, thematic analysis approach we analyzed contextual, first-, second-, and third- person data from the perspective of Phenomenological Variant of Ecological Systems Theory (PVEST). RESULTS: Results suggest Khali is an effective social change agent due to five interrelated factors. Analyzing Khali's life through the lens of PVEST also revealed his experiences resulted in two realizations central to him becoming a social change agent: the people and services that are supposed to serve youth at times do not, and; individuals like him can step up to meet youth needs. CONCLUSIONS: Results point to several important lessons related to transformational leadership theory that can enable YDP leaders to serve as social change agents.


Assuntos
Boxe , Mudança Social , Masculino , Adolescente , Humanos , Liderança , Exercício Físico
2.
J Phys Chem A ; 126(38): 6762-6766, 2022 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-36099399

RESUMO

The thermodynamics of sulfuric acid-water clusters is important for modeling new particle formation in the atmosphere. Particle number densities obtained at 296 K from a photolytic flow reactor are greatly overpredicted by the Sulfuric Acid Water Nucleation (SAWNUC) model. Empirical, temperature-dependent adjustments to the SAWNUC model allow for better agreement with the data obtained at 296 K, while maintaining reasonable agreement with the data of Hanson and Lovejoy at 242 K. Even though these adjustments result in extensive decreases in the modeled particle number densities at room temperature, the changes in the standard Gibbs reaction energies are all less than 1 kcal/mol.

3.
Artigo em Inglês | MEDLINE | ID: mdl-35842552

RESUMO

Previous research on the relationship between parenting style and social anxiety in Chinese youth has been inconsistent, which has made it difficult to consider whether improving parenting may serve as a preventative intervention for social anxiety. The current study aimed to clarify these inconsistencies by examining the strength of the association between positive/negative parenting style and social anxiety among Chinese students and the role of certain moderators in those associations. A meta-analysis was conducted on 53 studies with a total sample of 26,024 Chinese mainland students. Separate analyses were conducted for positive parenting style and social anxiety (N = 24,081), and negative parenting style and social anxiety (N = 24,933). Findings suggest a small negative association exists between positive parenting style and social anxiety, and a small positive association exists between negative parenting style and child social anxiety. Analyses suggested type of social anxiety measures, developmental stage, and gender all moderated the relationships between parenting style and social anxiety. Results clarify the direction of the relationship between parenting and social anxiety amongst Chinese youth and point to particular implications and future directions for policy, practice, and research.

4.
J Community Psychol ; 50(7): 3023-3043, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35139238

RESUMO

The current study uplifts the efforts of community-based college access and success programs (CAS) to support the college preparation, matriculation, and persistence of underserved students during COVID-19. Fifty-eight CAS across the United States completed an online survey that gathered information about organizational demographics, COVID-19 challenges, responses to challenges, and communication with constituents and funding needs during COVID-19. Results suggested CAS faced multiple challenges due to COVID-19 that affected the organization, staff, and constituents. Results also revealed organizations of varying sizes, locations, and demographics responded to challenges by revising existing programming for students, creating new programming for students and caretakers, and updating staff policies to meet ongoing and emergent needs despite limited resources. CAS are essential service providers for students who are under- and mis-served in formal education systems. Recommendations are provided for how such organizations can be invested in and better prepared for future disruptions.


Assuntos
COVID-19 , Humanos , Organizações , Estudantes , Estados Unidos , Universidades
5.
J Community Psychol ; 50(2): 778-796, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34358349

RESUMO

Nearly 30% of all U.S. youth attend summer camp each year, making it one of the broadest reaching out-of-school-time interventions in the country. Camp provides a space for seasonal employees, who are often emerging adults, to explore work values and identity, engage in mentoring and support opportunities, and stay connected to a community larger than themselves. However, research on camp experiences also suggests camp settings and expectations around emotional and physical care can cause counselors to experience burnout, compassion fatigue, and reduced job satisfaction. Using participatory culture-specific consultation, the current study addressed a gap in the literature about systemic interventions to manage camp counselor mental health by designing, implementing, and evaluating a mental health consultation model at one of the largest YMCA summer camps in the country. Results suggest the intervention effectively addressed certain administrator and staff needs; results also suggest the model could be refined to more effectively respond to the particular contextual challenges of summer camps. Implications and recommendations for other summer camps are discussed.


Assuntos
Acampamento , Tutoria , Adolescente , Adulto , Acampamento/psicologia , Humanos , Satisfação no Emprego , Saúde Mental , Encaminhamento e Consulta
6.
J Neurochem ; 136 Suppl 1: 49-62, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25708596

RESUMO

Microglia are a specialized population of myeloid cells that mediate CNS innate immune responses. Efforts to identify the cellular and molecular mechanisms that regulate microglia behaviors have been hampered by the lack of effective tools for manipulating gene expression. Cultured microglia are refractory to most chemical and electrical transfection methods, yielding little or no gene delivery and causing toxicity and/or inflammatory activation. Recombinant adeno-associated viral (rAAVs) vectors are non-enveloped, single-stranded DNA vectors commonly used to transduce many primary cell types and tissues. In this study, we evaluated the feasibility and efficiency of utilizing rAAV serotype 2 (rAAV2) to modulate gene expression in cultured microglia. rAAV2 yields high transduction and causes minimal toxicity or inflammatory response in both neonatal and adult microglia. To demonstrate that rAAV transduction can induce functional protein expression, we used rAAV2 expressing Cre recombinase to successfully excise a LoxP-flanked miR155 gene in cultured microglia. We further evaluated rAAV serotypes 5, 6, 8, and 9, and observed that all efficiently transduced cultured microglia to varying degrees of success and caused little or no alteration in inflammatory gene expression. These results provide strong encouragement for the application of rAAV-mediated gene expression in microglia for mechanistic and therapeutic purposes. Neonatal microglia are functionally distinct from adult microglia, although the majority of in vitro studies utilize rodent neonatal microglia cultures because of difficulties of culturing adult cells. In addition, cultured microglia are refractory to most methods for modifying gene expression. Here, we developed a novel protocol for culturing adult microglia and evaluated the feasibility and efficiency of utilizing Recombinant Adeno-Associated Virus (rAAV) to modulate gene expression in cultured microglia.


Assuntos
Técnicas de Cultura de Células/métodos , Dependovirus/genética , Vetores Genéticos/genética , Microglia/fisiologia , Transdução Genética/métodos , Animais , Animais Recém-Nascidos , Células Cultivadas , Feminino , Vetores Genéticos/administração & dosagem , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos
7.
Brain ; 138(Pt 7): 2005-19, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25981964

RESUMO

Endophilin-B1, also known as Bax-interacting factor 1 (Bif-1, and encoded by SH3GLB1), is a multifunctional protein involved in apoptosis, autophagy and mitochondrial function. We recently described a unique neuroprotective role for neuron-specific alternatively spliced isoforms of endophilin-B1. To examine whether endophilin-B1-mediated neuroprotection could be a novel therapeutic target for Alzheimer's disease we used a double mutant amyloid precursor protein and presenilin 1 (APPswe/PSEN1dE9) mouse model of Alzheimer's disease and observed that expression of neuron-specific endophilin-B1 isoforms declined with disease progression. To determine if this reduction in endophilin-B1 has a functional role in Alzheimer's disease pathogenesis, we crossed endophilin-B1(-/-) mice with APPswe/PSEN1dE9 mice. Deletion of endophilin-B1 accelerated disease onset and progression in 6-month-old APPswe/PSEN1dE9/endophilin-B1(-/-) mice, which showed more plaques, astrogliosis, synaptic degeneration, cognitive impairment and mortality than APPswe/PSEN1dE9 mice. In mouse primary cortical neuron cultures, overexpression of neuron-specific endophilin-B1 isoforms protected against amyloid-ß-induced apoptosis and mitochondrial dysfunction. Additionally, protein and mRNA levels of neuron-specific endophilin-B1 isoforms were also selectively decreased in the cerebral cortex and in the synaptic compartment of patients with Alzheimer's disease. Flow sorting of synaptosomes from patients with Alzheimer's disease demonstrated a negative correlation between amyloid-ß and endophilin-B1 levels. The importance of endophilin-B1 in neuronal function was further underscored by the development of synaptic degeneration and cognitive and motor impairment in endophilin-B1(-/-) mice by 12 months. Our findings suggest that endophilin-B1 is a key mediator of a feed-forward mechanism of Alzheimer's disease pathogenesis where amyloid-ß reduces neuron-specific endophilin-B1, which in turn enhances amyloid-ß accumulation and neuronal vulnerability to stress.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Doença de Alzheimer/metabolismo , Neurônios/patologia , Idoso de 80 Anos ou mais , Doença de Alzheimer/patologia , Animais , Western Blotting , Células Cultivadas , Modelos Animais de Doenças , Feminino , Citometria de Fluxo , Imunofluorescência , Humanos , Immunoblotting , Masculino , Aprendizagem em Labirinto , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sinaptossomos/metabolismo , Sinaptossomos/patologia
8.
Phys Chem Chem Phys ; 18(48): 32999-33008, 2016 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-27886282

RESUMO

We investigate the Ã-band photodissociation of CHBrCl2 at 215, 225, 235, 245, 255, and 265 nm. Following C-Br bond cleavage, resonance enhanced multiphoton ionization and time of flight mass spectrometry provide selective detection of the two product channels, from which we quantify the relative quantum yield of Br/Br* production. Velocity-map imaging of the photofragments allows us to determine the energy partitioning as a function of the photolysis energy for different exit channels. The anisotropy present in the imaging data suggests that absorption to the 3Q0+(A') state is important throughout the entire region we study, though competition with other excited states is evident. The 3Q0+(A') state forms an avoided crossing with the 1Q1(A') state, and we find that the propensity for adiabatic passage through this crossing region dictates the Br yield at longer wavelengths. At shorter wavelengths, Br production from excited states not subject to the crossing is more evident. While we find that spin-orbit excitation comes largely at the expense of the CHCl2 internal energy, both channels still produce highly excited CHCl2 photofragments. Impulsive modeling and comparison with similar halomethane dissociations suggests that a high degree of rotational excitation is present, dictated by the torque inherent in Cs-symmetry dissociation and the angular dependence of the potential.

9.
J Chem Phys ; 142(1): 014310, 2015 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-25573564

RESUMO

We investigate the vibrational predissociation dynamics of the hydrogen-bonded 3-aminophenol-ammonia cluster (3-AP-NH3) in the OH and NH stretching regions. Vibrational excitation provides enough energy to dissociate the cluster into its constituent 3-AP and NH3 monomers, and we detect the 3-AP fragments via (1 + 1) resonance-enhanced multiphoton ionization (REMPI). The distribution of vibrational states of the 3-AP fragment suggests the presence of two distinct dissociation pathways. The first dissociation channel produces a broad, unstructured feature in the REMPI-action spectrum after excitation of any of the OH or NH stretching vibrations, pointing to a nearly statistical dissociation pathway with extensive coupling among the vibrations in the cluster during the vibrational predissociation. The second dissociation channel produces distinct, resolved features on top of the broad feature but only following excitation of the OH or symmetric NH3 stretch in the cluster. This striking mode-specificity is consistent with strong coupling of these two modes to the dissociation coordinate (the O-H⋯N bond). The presence of clearly resolved transitions to the electronic origin and to the 10a(2) + 10b(2) state of the cis-3-AP isomer shows that vibrational excitation is driving the isomerization of the trans-3-AP-NH3 isomer to the cis-3-AP-NH3 isomer in the course of the dissociation.

10.
J Am Chem Soc ; 136(29): 10361-72, 2014 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-25009990

RESUMO

We use gas-phase negative ion photoelectron spectroscopy to study the quasilinear carbene propargylene, HCCCH, and its isotopologue DCCCD. Photodetachment from HCCCH­ affords the X̃(3B) ground state of HCCCH and its ã(1A), b̃ (1B), d̃(1A2), and B̃(3A2) excited states. Extended, negatively anharmonic vibrational progressions in the X̃(3B) ground state and the open-shell singlet b̃ (1B) state arise from the change in geometry between the anion and the neutral states and complicate the assignment of the origin peak. The geometry change arising from electron photodetachment results in excitation of the ν4 symmetric CCH bending mode, with a measured fundamental frequency of 363 ± 57 cm(­1) in the X̃(3B) state. Our calculated harmonic frequency for this mode is 359 cm(­1). The Franck­Condon envelope of this progression cannot be reproduced within the harmonic approximation. The spectra of the ã(1A), d̃(1A2), and B̃(3A2) states are each characterized by a short vibrational progression and a prominent origin peak, establishing that the geometries of the anion and these neutral states are similar. Through comparison of the HCCCH­ and DCCCD­ photoelectron spectra, we measure the electron affinity of HCCCH to be 1.156 ± (0.095)(0.010) eV, with a singlet­triplet splitting between the X̃(3B) and the ã(1A) states of ΔEST = 0.500 ± (0.01)(0.10) eV (11.5 ± (0.2)(2.3) kcal/mol). Experimental term energies of the higher excited states are T0 [b̃(1B)] = 0.94 ± (0.20)(0.22) eV, T0 [d̃(1A2)] = 3.30 ± (0.02)(0.10) eV, T0 [B̃(3A2)] = 3.58 ± (0.02)(0.10) eV. The photoelectron angular distributions show significant π character in all the frontier molecular orbitals, with additional σ character in orbitals that create the X̃(3B) and b̃(1B) states upon electron detachment. These results are consistent with a quasilinear, nonplanar, doubly allylic structure of X̃(3B) HCCCH with both diradical and carbene character.

11.
J Chem Phys ; 141(8): 084305, 2014 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-25173012

RESUMO

The photofragmentation dynamics of BrCN(-) in the 270-355 nm and the 430-600 nm wavelength regions is explored both experimentally and theoretically. In the case of excitation between 430 nm and 600 nm, it is found that the molecular ion accesses two dissociation channels with a measured 60:40 branching ratio that is nearly constant over this range of photon energies. The dominant product channel corresponds to Br(-) + CN, while the second channel correlates to spin-orbit excited Br(*) with CN(-). A larger wavelength dependence of the branching ratio is observed at shorter wavelengths, where the fraction of Br(-) based products ranges from 80% to 95% at 355 nm and 270 nm, respectively. These branching ratios are reproduced and the mechanisms are explored by quantum dynamics calculations based on ground and excited state potential energy surfaces for BrCN(-), evaluated at the SO-MRCISD level of theory. It is found that the electronic states that correlate to the two observed product channels are coupled through the spin-orbit terms in the electronic Hamiltonian. The strength of this coupling displays a strong dependence on the Br-CN angle. Specifically, after promotion to the excited state that is energetically accessible with 430-600 nm photons, it is found that when the wave packet accesses Br-CN separations of between 4 Å and 6 Å, predominantly the Br(-) + CN products are formed when the Br-CN angle is smaller than 120°. For larger values of the Br-CN angle, the Br(*) + CN(-) channel dominates. At the shorter wavelength excitation, the dynamics is complicated by a pair of states that correlate to electronically excited CN(*) + Br(-) products that borrow oscillator strength from the bright state, leading to an increase in the amount of Br(-) relative to CN(-). The implications of these findings are discussed and compared to the experimentally measured product branching ratios for the photodissociation of BrCN(-).

12.
J Neurochem ; 127(5): 592-9, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23952003

RESUMO

Microglia, the resident innate immune cells of the CNS, are the primary defenders against microbes and critical to CNS remodeling. Dysregulation of microglial behavior can lead to unchecked pro-inflammatory activity and subsequent neurodegeneration. The molecular mechanisms leading to chronic inflammation and microglial dysfunction in neurodegenerative diseases are not well-understood. It is known that patients with Presenilin 2 (PS2) mutations develop autosomal dominant Alzheimer disease. We have shown that a lack of normal PS2 function is associated with exaggerated microglia pro-inflammatory responses in vitro. To identify pathways by which PS2 regulates microglia and determine how PS2 dysfunction may lead to altered inflammatory pathways, we pursued an unbiased array approach to assess differential expression of microRNAs between murine PS2 knockout (KO) and wild-type microglia. We identified miR146, a negative regulator of monocyte pro-inflammatory response, as constitutively down-regulated in PS2 KO microglia. Consistent with a state of miR146 suppression, we found that PS2 KO microglia express higher levels of the miR146 target protein interleukin-1 receptor-associated kinase-1, and have increased NFκB transcriptional activity. We hypothesize that PS2 impacts microglial responses through modulation of miR146a. PS2 dysfunction, through aging or mutation, may contribute to neurodegeneration by influencing the pro-inflammatory behavior of microglia. Presenilin 2 (PS2), a membrane associated protease, has been implicated in the pathogenesis of Alzheimer disease. We have previously shown that PS2 plays an important role in curbing the proinflammatory response in microglia. Here, we report the novel finding that PS2 participates in maintaining the basal and cytokine induced expression of the innate immunity regulating microRNA, miR146. These data suggest one mechanism by which PS2 works to reign in proinflammatory microglial behavior and that PS2 dysfunction or deficiency could thus result in unchecked proinflammatory activation contributing to neurodegeneration.


Assuntos
MicroRNAs/metabolismo , Microglia/imunologia , Presenilina-2/genética , Animais , Animais Recém-Nascidos , Quinases Associadas a Receptores de Interleucina-1/genética , Quinases Associadas a Receptores de Interleucina-1/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , MicroRNAs/imunologia , Microglia/citologia , NF-kappa B/imunologia , NF-kappa B/metabolismo , Presenilina-2/imunologia , Cultura Primária de Células , Transcrição Gênica/imunologia
13.
J Phys Chem A ; 117(50): 13310-8, 2013 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-23819777

RESUMO

The ultraviolet (UV) photodissociation of mass-selected ICN(-)Ar(n) and ICN(-)(CO2)n clusters (n = 0-5) is studied using a secondary reflectron mass spectrometer. Relative photodissociation cross sections of bare ICN(-) show the dominance of the I(-) photoproduct from 270 to 355 nm, the entire wavelength range studied. UV excitation populates both the (2)Σ(+) state that produces I* + CN(-) and the (2)Π states that produce I(-) + CN*. While the excited (2)Π states directly produce I(-), excitation to the (2)Σ(+) state also produces some I(-) product via nonadiabatic transitions to the (2)Π(1/2) state, which produces I(-) + CN. Partial solvation of the anion by Ar atoms or CO2 molecules alters the UV-branching percentages between the various dissociation channels: I* + CN(-) and I(-) + CN or I(-) + CN*. In addition, solvation by two or more Ar atoms or three or more CO2 molecules results in recombination, reforming ICN(-). Examination of the potential surfaces and transition moments in combination with the results of quantum dynamics calculations performed on the relevant excited states assist in the analysis of the experimental results.

14.
J Chem Phys ; 139(6): 064315, 2013 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-23947863

RESUMO

Photodissociation of ICN(-)(CO2)n, n = 0-18, with 500-nm excitation is investigated using a dual time-of-flight mass spectrometer. Photoabsorption to the (2)Π(1/2) state is detected using ionic-photoproduct action spectroscopy; the maximum absorption occurs around 490 nm. Ionic-photoproduct distributions were determined for ICN(-)(CO2)n at 500 nm. Following photodissociation of bare ICN(-) via 430-650 nm excitation, a small fraction of CN(-) is produced, suggesting that nonadiabatic effects play a role in the photodissociation of this simple anion. Electronic structure calculations, carried out at the MR-SO-CISD level of theory, were used to evaluate the potential-energy surfaces for the ground and excited states of ICN(-). Analysis of the electronic structure supports the presence of nonadiabatic effects in the photodissociation dynamics. For n ≥ 2, the major ionic photoproduct has a mass corresponding to either partially solvated CN(-) or partially solvated [NCCO2](-).

15.
J Chem Phys ; 136(12): 124310, 2012 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-22462860

RESUMO

Infrared-action spectroscopy of small ammonia clusters obtained by detecting ammonia fragments from vibrational predissociation provides an estimate of the dissociation energy of the trimer. The product detection uses resonance enhanced multiphoton ionization (REMPI) of individual rovibrational states of ammonia identified by simulations using a consistent set of ground-electronic-state spectroscopic constants in the PGOPHER program. Comparison of the infrared-action spectra to a less congested spectrum measured in He droplets [M. N. Slipchenko, B. G. Sartakov, A. F. Vilesov, and S. S. Xantheas, J. Phys. Chem. A 111, 7460 (2007)] identifies the contributions from the dimer and the trimer. The relative intensities of the dimer and trimer features in the infrared-action spectra depend on the amount of energy available for breaking the hydrogen bonds in the cluster, a quantity that depends on the energy content of the detected fragment. Infrared-action spectra for ammonia fragments with large amounts of internal energy have almost no trimer component because there is not enough energy available to break two bonds in the cyclic trimer. By contrast, infrared-action spectra for fragments with low amounts of internal energy have a substantial trimer component. Analyzing the trimer contribution quantitatively shows that fragmentation of the trimer into a monomer and dimer requires an energy of 1700 to 1800 cm(-1), a range that is consistent with several theoretical estimates.

16.
J Chem Phys ; 136(4): 044313, 2012 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-22299877

RESUMO

Negative-ion photoelectron spectroscopy of ICN(-) (X̃ (2)Σ(+)) reveals transitions to the ground electronic state (X̃ (1)Σ(+)) of ICN as well as the first five excited states ((3)Π(2), (3)Π(1), Π(0(-) ) (3), Π(0(+) ) (3), and (1)Π(1)) that make up the ICN A continuum. By starting from the equilibrium geometry of the anion, photoelectron spectroscopy characterizes the electronic structure of ICN at an elongated I-C bond length of 2.65 Å. Because of this bond elongation, the lowest three excited states of ICN ((3)Π(2), (3)Π(1), and Π(0(-) ) (3)) are resolved for the first time in the photoelectron spectrum. In addition, the spectrum has a structured peak that arises from the frequently studied conical intersection between the Π(0(+) ) (3) and (1)Π(1) states. The assignment of the spectrum is aided by MR-SO-CISD calculations of the potential energy surfaces for the anion and neutral ICN electronic states, along with calculations of the vibrational levels supported by these states. Through thermochemical cycles involving spectrally narrow transitions to the excited states of ICN, we determine the electron affinity, EA(ICN), to be 1.34(5) (+0.04∕-0.02) eV and the anion dissociation energy, D(0)(X̃ (2)Σ(+) I-CN(-)), to be 0.83 (+0.04/-0.02) eV.

17.
J Chem Phys ; 136(13): 134312, 2012 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-22482557

RESUMO

A joint experimental-theoretical study has been carried out on electronic states of propadienylidene (H(2)CCC), using results from negative-ion photoelectron spectroscopy. In addition to the previously characterized X(1)A(1) electronic state, spectroscopic features are observed that belong to five additional states: the low-lying ã(3)B(1) and b(3)A(2) states, as well as two excited singlets, Ã(1)A(2) and B(1)B(1), and a higher-lying triplet, c(3)A(1). Term energies (T(0), in cm(-1)) for the excited states obtained from the data are: 10,354±11 (ã(3)B(1)); 11,950±30 (b(3)A(2)); 20,943±11 (c(3)A(1)); and 13,677±11 (Ã(1)A(2)). Strong vibronic coupling affects the Ã(1)A(2) and B(1)B(1) states as well as ã(3)B(1) and b(3)A(2) and has profound effects on the spectrum. As a result, only a weak, broadened band is observed in the energy region where the origin of the B(1)B(1) state is expected. The assignments here are supported by high-level coupled-cluster calculations and spectral simulations based on a vibronic coupling Hamiltonian. A result of astrophysical interest is that the present study supports the idea that a broad absorption band found at 5450 Å by cavity ringdown spectroscopy (and coincident with a diffuse interstellar band) is carried by the B(1)B(1) state of H(2)CCC.

18.
Angew Chem Int Ed Engl ; 51(11): 2651-3, 2012 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-22298354

RESUMO

In a spin: the dynamics of photoexcited ICN(-) (Ar)(0-5) are presented. Photodetachment produces quasi-thermal electron emission that leaves ICN with up to 2.85 eV of internal energy. Photodissociation at 2.5 eV leads to one-atom caging and highly solvated anion products. Calculations indicate efficient energy transfer into CN rotation upon excitation to the (2)Π(1/2) excited state. CN rotation is vital to explain the unique dynamics observed.

19.
Glia ; 59(10): 1402-13, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21598312

RESUMO

Several neurodegenerative diseases are influenced by the innate immune response in the central nervous system (CNS). Microglia have proinflammatory and subsequently neurotoxic actions as well as anti-inflammatory functions that promote recovery and repair. Very little is known about the transcriptional control of these specific microglial behaviors. We have previously shown that in HIV-associated neurocognitive disorders (HAND), the transcription factor p53 accumulates in microglia and that microglial p53 expression is required for the in vitro neurotoxicity of the HIV coat glycoprotein gp120. These findings suggested a novel function for p53 in regulating microglial activation. Here, we report that in the absence of p53, microglia demonstrate a blunted response to interferon-γ, failing to increase expression of genes associated with classical macrophage activation or secrete proinflammatory cytokines. Microarray analysis of global gene expression profiles revealed increased expression of genes associated with anti-inflammatory functions, phagocytosis, and tissue repair in p53 knockout (p53(-/-)) microglia compared with those cultured from strain matched p53 expressing (p53(+/+)) mice. We further observed that p53(-/-) microglia demonstrate increased phagocytic activity in vitro and expression of markers for alternative macrophage activation both in vitro and in vivo. In HAND brain tissue, the alternative activation marker CD163 was expressed in a separate subset of microglia than those demonstrating p53 accumulation. These data suggest that p53 influences microglial behavior, supporting the adoption of a proinflammatory phenotype, while p53 deficiency promotes phagocytosis and gene expression associated with alternative activation and anti-inflammatory functions.


Assuntos
Córtex Cerebral/patologia , Regulação da Expressão Gênica/genética , Microglia/metabolismo , Fenótipo , Proteína Supressora de Tumor p53/metabolismo , Análise de Variância , Animais , Antígenos CD/metabolismo , Apoptose/efeitos dos fármacos , Apoptose/genética , Linhagem Celular Transformada , Córtex Cerebral/citologia , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/metabolismo , Transtornos Cognitivos/virologia , Ensaio de Imunoadsorção Enzimática/métodos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Proteína gp120 do Envelope de HIV/farmacologia , Infecções por HIV/induzido quimicamente , Ataque Isquêmico Transitório/metabolismo , Ataque Isquêmico Transitório/patologia , Masculino , Camundongos , Camundongos Knockout , Microglia/efeitos dos fármacos , Análise de Sequência com Séries de Oligonucleotídeos , Fagocitose/efeitos dos fármacos , Fatores de Tempo , Proteína Supressora de Tumor p53/deficiência , Proteína Supressora de Tumor p53/genética
20.
J Chem Phys ; 135(8): 084312, 2011 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-21895190

RESUMO

Experiments using infrared excitation of either the intramolecular symmetric N-H stretch (ν(NH,S)) or the intramolecular antisymmetric N-H stretch (ν(NH,A)) of the ammonia dimer ((NH(3))(2)) in combination with velocity-map ion imaging provide new information on the dissociation energy of the dimer and on the energy disposal in its dissociation. Ion imaging using resonance enhanced multiphoton ionization to probe individual rovibrational states of one of the ammonia monomer fragments provides recoil speed distributions. Analyzing these distributions for different product states gives a dissociation energy of D(0) = 660 ± 20 cm(-1) for the dimer. Fitting the distributions shows that rotations are excited up to their energetic limit and determines the correlation of the fragment vibrations. The fragments NH(3)(ν(2) = 3(+)) and NH(3)(ν(2) = 2(+)) have a vibrational ground-state partner NH(3)(ν = 0), but NH(3)(ν(2) = 1(+)) appears in partnership with another fragment in ν(2) = 1. This propensity is consistent with the idea of minimizing the momentum gap between the initial and final states by depositing a substantial fraction of the available energy into internal excitation.


Assuntos
Amônia/química , Dimerização , Vibração
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