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1.
Phys Rev Lett ; 125(26): 262301, 2020 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-33449792

RESUMO

Flow coefficients v_{n} of the orders n=1-6 are measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI for protons, deuterons, and tritons as a function of centrality, transverse momentum, and rapidity in Au+Au collisions at sqrt[s_{NN}]=2.4 GeV. Combining the information from the flow coefficients of all orders allows us to construct for the first time, at collision energies of a few GeV, a multidifferential picture of the angular emission pattern of these particles. It reflects the complicated interplay between the effect of the central fireball pressure on the emission of particles and their subsequent interaction with spectator matter. The high precision information on higher order flow coefficients is a major step forward in constraining the equation of state of dense baryonic matter.

2.
Phys Rev Lett ; 123(2): 022002, 2019 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-31386541

RESUMO

We present the first observation of K^{-} and ϕ absorption within nuclear matter by means of π^{-}-induced reactions on C and W targets at an incident beam momentum of 1.7 GeV/c studied with HADES at SIS18/GSI. The double ratio (K^{-}/K^{+})_{W}/(K^{-}/K^{+})_{C} is found to be 0.319±0.009(stat)_{-0.012}^{+0.014}(syst) indicating a larger absorption of K^{-} in heavier targets as compared to lighter ones. The measured ϕ/K^{-} ratios in π^{-}+C and π^{-}+W reactions within the HADES acceptance are found to be equal to 0.55±0.04(stat)_{-0.07}^{+0.06}(syst) and to 0.63±0.06(stat)_{-0.11}^{+0.11}(syst), respectively. The similar ratios measured in the two different reactions demonstrate for the first time experimentally that the dynamics of the ϕ meson in nuclear medium is strongly coupled to the K^{-} dynamics. The large difference in the ϕ production off C and W nuclei is discussed in terms of a strong ϕN in-medium coupling. These results are relevant for the description of heavy-ion collisions and the structure of neutron stars.

3.
BMC Microbiol ; 19(1): 132, 2019 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-31195965

RESUMO

BACKGROUND: Xenorhabdus spp. live in close symbiosis with nematodes of the Steinernema genus. Steinernema nematodes infect an insect larva and release their symbionts into the haemocoel of the insect. Once released into the haemocoel, the bacteria produce bioactive compounds to create a semi-exclusive environment by inhibiting the growth of bacteria, yeasts and molds. The antimicrobial compounds thus far identified are xenocoumacins, xenortides, xenorhabdins, indole derivatives, xenoamicins, bicornutin and a number of antimicrobial peptides. The latter may be linear peptides such as the bacteriocins xenocin and xenorhabdicin, rhabdopeptides and cabanillasin, or cyclic, such as PAX lipopeptides, taxlllaids, xenobactin and szentiamide. Thus far, production of antimicrobial compounds have been reported for Xenorhabdus nematophila, Xenorhabdus budapestensis, Xenorhabdus cabanillasii, Xenorhabdus kozodoii, Xenorhabdus szentirmaii, Xenorhabdus doucetiae, Xenorhabdus mauleonii, Xenorhabdus indica and Xenorhabdus bovienii. Here we describe, for the first time, PAX lipopeptides and xenocoumacin 2 produced by Xenorhabdus khoisanae. These compounds were identified using ultraperformance liquid chromatography, linked to high resolution electrospray ionisation mass spectrometry and tandem mass spectrometry. RESULTS: Cell-free supernatants of X. khoisanae SB10 were heat stable and active against Bacillus subtilis subsp. subtilis, Escherichia coli and Candida albicans. Five lysine-rich lipopeptides from the PAX group were identified in HPLC fractions, with PAX1' and PAX7 present in the highest concentrations. Three novel PAX7 peptides with putative enoyl modifications and two linear analogues of PAX1' were also detected. A small antibiotic compound, yellow in colour and λmax of 314 nm, was recovered from the HPLC fractions and identified as xenocoumacin 2. The PAX lipopeptides and xenocoumacin 2 correlated with the genes and gene clusters in the genome of X. khoisanae SB10. CONCLUSION: With UPLC-MS and MSe analyses of compounds in the antimicrobial complex of X. khoisanae SB10, a number of PAX peptides and a xenocoumacin were identified. The combination of pure PAX1' peptide with xenocoumacin 2 resulted in high antimicrobial activity. Many of the fractions did, however, contain labile compounds and some fractions were difficult to resolve. It is thus possible that strain SB10 may produce more antimicrobial compounds than reported here, as suggested by the APE Ec biosynthetic complex. Further research is required to develop these broad-spectrum antimicrobial compounds into drugs that may be used in the fight against microbial infections.


Assuntos
Anti-Infecciosos/farmacologia , Benzopiranos/farmacologia , Lipopeptídeos/metabolismo , Xenorhabdus/fisiologia , Anti-Infecciosos/metabolismo , Bacillus subtilis/efeitos dos fármacos , Proteínas de Bactérias , Benzopiranos/metabolismo , Vias Biossintéticas , Candida albicans/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Escherichia coli/efeitos dos fármacos , Espectrometria de Massas por Ionização por Electrospray , Simbiose , Espectrometria de Massas em Tandem , Xenorhabdus/genética , Xenorhabdus/metabolismo
4.
Osteoarthritis Cartilage ; 26(8): 1110-1117, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29803826

RESUMO

OBJECTIVES: The chondrocytes' pericellular matrix acts as a mechanosensor by sequestering growth factors that are bound to heparan sulfate (HS) proteoglycans. Heparanase is the sole mammalian enzyme with HS degrading endoglycosidase activity. Here, we aimed to ascertain whether heparanase plays a role in modulating the anabolic or catabolic responses of human articular chondrocytes. METHODS: Primary chondrocytes were incubated with pro-heparanase and catabolic and anabolic gene expression was analyzed by quantitative polymerase chain reaction (PCR). MMP13 enzymatic activity in the culture medium was measured with a specific fluorescent assay. Extracellular regulated kinase (ERK) phosphorylation was evaluated by Western blot. Human osteoarthritis (OA) cartilage was assessed for heparanase expression by reverse-transcriptase PCR, by Western blot and by a heparanase enzymatic activity assay. RESULTS: Cultured chondrocytes rapidly associated with and activated pro-heparanase. Heparanase induced the catabolic genes MMP13 and ADAMTS4 and the secretion of active MMP13, and down-regulated the anabolic genes ACAN and COL2A1. PG545, a HS-mimetic, inhibited the effects of heparanase. Heparanase expression and enzymatic activity were demonstrated in adult human osteoarthritic cartilage. Heparanase induced ERK phosphorylation in cultured chondrocytes and this could be inhibited by PG545, by fibroblast growth factor 2 (FGF2) neutralizing antibodies and by a FGF-receptor inhibitor. CONCLUSIONS: Heparanase is active in osteoarthritic cartilage and induces catabolic responses in primary human chondrocytes. This response is due, at least in part, to the release of soluble growth factors such as FGF2.


Assuntos
Cartilagem Articular/enzimologia , Condrócitos/enzimologia , Glucuronidase/metabolismo , Osteoartrite/enzimologia , Adulto , Western Blotting , Cartilagem Articular/citologia , Cartilagem Articular/metabolismo , Cartilagem Articular/patologia , Condrócitos/metabolismo , Humanos , Metaloproteinase 13 da Matriz/metabolismo , Osteoartrite/metabolismo , Osteoartrite/patologia , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa
5.
Pathologe ; 36(5): 477-84, 2015 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-26280511

RESUMO

Macrophages are important factors in the pathogenesis and prognosis of malignant tumors and represent a possible target for therapeutic intervention. Depending on the tumor entity and the prevalent polarization status, macrophages can be associated with a favorable or unfavorable clinical outcome. It is becoming clear, however, that the conventional definitions of M1 polarized tumor inhibitory and M2 polarized tumor promoting macrophages do not adequately reflect the heterogeneity and plasticity of macrophages. Macrophages can support tumor growth through direct interactions with the neoplastic cells, by promoting tissue remodeling and angiogenesis and by inhibiting local immune reactions. To achieve comparability of clinical studies, it will be necessary to reach a consensus nomenclature of macrophage polarization. Furthermore, methods for the quantitative characterization of macrophage populations in malignant tumors will have to be standardized. It is unlikely that single marker immunohistochemistry will be adequate in this context. In any case it is necessary to provide unequivocal information regarding the markers or marker combinations used.


Assuntos
Diferenciação Celular/fisiologia , Macrófagos/patologia , Macrófagos/fisiologia , Neoplasias/patologia , Neoplasias/fisiopatologia , Plasticidade Celular/fisiologia , Polaridade Celular/fisiologia , Humanos , Tolerância Imunológica/fisiologia , Macrófagos/classificação , Neoplasias/irrigação sanguínea , Neoplasias/imunologia , Neovascularização Patológica/patologia , Neovascularização Patológica/fisiopatologia
6.
J Chem Phys ; 141(22): 22D521, 2014 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-25494792

RESUMO

Chloride anions permeate the bacterial NanC porin in physiological processes. Here we present a DFT-based QM/MM study of this porin in the presence of these anions. Comparison is made with classical MD simulations on the same system. In both QM/MM and classical approaches, the anions are almost entirely solvated by water molecules. However, the average water-Cl(-) distance is significantly larger in the first approach. Polarization effects of protein groups close to Cl(-) anion are sizeable. These effects might modulate the anion-protein electrostatic interactions, which in turn play a central role for selectivity mechanisms of the channel.


Assuntos
Proteínas da Membrana Bacteriana Externa/química , Cloretos/química , Proteínas de Escherichia coli/química , Escherichia coli/química , Porinas/química , Água/química , Sítios de Ligação , Ligação de Hidrogênio , Simulação de Dinâmica Molecular , Teoria Quântica , Termodinâmica
7.
Ann Oncol ; 25(10): 2042-2047, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25057171

RESUMO

BACKGROUND: The prognostic role of persistence of circulating tumor cells (CTC) after upfront tumor surgery for outcome of adjuvant (chemo)radiation in locally advanced squamous cell carcinoma of the head and neck (LASCCHN) was evaluated. PATIENTS AND METHODS: In this prospective study, peripheral blood samples from 144 patients with LASCCHN presenting after tumor resection for adjuvant treatment were analyzed for CTC. Their detection was correlated with tumor site, clinical risk factors, disease-free (DFS) and overall survival (OS). RESULTS: CTC were detected in 42 of 144 patients (29%). CTC detection was higher in cases with nodal involvement and in carcinomas located at the tonsil or base of tongue but was not influenced by age, smoking history, T stage, extracapsular lymph node extension, surgical margins or the human papillomavirus status. Overall, the presence of CTC was not predictive for OS or DFS. However, while in oropharyngeal carcinomas (OPC, n = 63), the detection of CTC was associated per trend with improved DFS [CTC+ versus CTC- (% of patients without evidence of disease at 2 years): 100% versus 79%; log rank: P = 0.059]; the reverse was observed for carcinomas from other sites (non-OPC, n = 81; CTC+ versus CTC-: 29% versus 75%; P = 0.001). In multivariate analysis, CTC remained an independent prognostic marker for DFS [hazard ratio (HR) 4.3, 95% confidence interval (CI) 1.7-10.9, P = 0.002] and OS (HR 2.7, 95% CI 1.2-6.3, P = 0.016) in non-OPC. CONCLUSIONS: Assessment of CTC in non-OPC should prove useful for identification of patients who benefit from treatment intensification. The basis for the good prognostic value of CTC in OPC has to be elucidated in future studies.


Assuntos
Quimiorradioterapia Adjuvante , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Recidiva Local de Neoplasia/tratamento farmacológico , Células Neoplásicas Circulantes/patologia , Prognóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/sangue , Carcinoma de Células Escamosas , Terapia Combinada , Intervalo Livre de Doença , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/patologia , Células Epiteliais/efeitos da radiação , Feminino , Neoplasias de Cabeça e Pescoço/sangue , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/sangue , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/radioterapia , Células Neoplásicas Circulantes/efeitos dos fármacos , Células Neoplásicas Circulantes/efeitos da radiação , Estudos Prospectivos , Carcinoma de Células Escamosas de Cabeça e Pescoço
8.
Surgeon ; 8(1): 20-7, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20222399

RESUMO

Professionalism has been identified as one of four domains of competency for surgical trainees in the UK. This implies that professionalism can be learned and assessed. The priorities of different professions and healthcare systems influence the value placed on different components of professionalism and UK surgeons need to identify the characteristics they would most value as part of an effective assessment process. The success of developing a taxonomy of non-technical skills for surgeons (NOTSS) can guide a similar process for a taxonomy for professionalism assessment. A multitude of assessment instruments for professionalism have been described in the literature but very few are valid, reliable or practical. For surgical trainees a number of assessment tools should be considered. A quantifiable tool using multi-source feedback could be the most practical for clinical surgeons to use. It is important, however, that it is not used to assess isolated behaviours but assess conduct within a surgical community of practice, and that the thinking process behind (un)professional behaviour is also understood, especially in stressful situations.


Assuntos
Competência Clínica/normas , Cirurgia Geral/normas , Médicos/normas , Especialidades Cirúrgicas/normas , Atitude do Pessoal de Saúde , Avaliação Educacional , Avaliação de Desempenho Profissional , Humanos
9.
Appl Microbiol Biotechnol ; 83(3): 521-7, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19333594

RESUMO

Novel thermophilic and alkaliphilic bacteria for the processing of bast fibres were isolated using hemp pectin as substrate. The strain PB94A, which showed the highest growth rate (micro = 0.5/h) was identified as Geobacillus thermoglucosidasius (DSM 21625). The strain grew optimally at 60 degrees C and pH 8.5. During growth on citrus pectin, the strain produced pectinolytic lyases, which were excreted into the medium. In contrast to the commercially available pectinase Bioprep 3000 L, the enzymes from G. thermoglucosidasius PB94A converted pectin isolated from hemp fibres. In addition to hemp pectin, the culture supernatant also degraded citrus, sugar beet and apple pectin and polygalacturonic acid. When hemp fibres were incubated with the cell-free fermentation broth of G. thermoglucosidasius PB94A, the fineness of the fibres increased. The strain did not produce any cellulases, which is important in order to avoid damaging the fibres during incubation. Therefore, these bacteria or their enzymes can be used to produce fine high-quality hemp fibres.


Assuntos
Álcalis/metabolismo , Bactérias/isolamento & purificação , Bactérias/metabolismo , Cannabis/química , Pectinas/metabolismo , Bactérias/química , Bactérias/genética , Proteínas de Bactérias/metabolismo , Cannabis/metabolismo , Temperatura Alta , Dados de Sequência Molecular , Poligalacturonase/metabolismo
10.
Neuroscience ; 159(1): 47-58, 2009 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-19135135

RESUMO

Multiple theories have been proposed for sensation seeking and vulnerability to impulse-control disorders [Zuckerman M, Kuhlman DM (2000) Personality and risk-taking: Common biosocial factors. J Pers 68:999-1029], and many of these rely on a dopamine system deficit. Available animal models reproduce only some behavioral symptoms and seem devoid of construct validity. We used lentivirus tools for over-expressing or silencing the dopamine transporter (DAT) and we evaluated the resulting behavioral profiles in terms of motivation and self-control. Wistar adult rats received stereotaxic inoculation of a lentivirus that allowed localized intra-accumbens delivery of a DAT gene enhancer/silencer, or the green fluorescent protein, GFP. These animals were studied for intolerance to delay, risk proneness and novelty seeking. As expected, controls shifted their demanding from a large reward toward a small one when the delivery of the former was increasingly delayed (or uncertain). Interestingly, in the absence of general locomotor effects, DAT over-expressing rats showed increased impulsivity (i.e. a more marked shift of demanding from the large/delayed toward the small/soon reward), and increased risk proneness (i.e. a less marked shift from the large/uncertain toward the small/sure reward), compared with controls. Rats with enhanced or silenced DAT expression did not show any significant preference for a novel environment. In summary, consistent with literature on comorbidity between attention-deficit/hyperactivity disorder and pathological gambling, we demonstrate that DAT over-expression in rats' nucleus accumbens leads to impulsive and risk prone phenotype. Thus, a reduced dopaminergic tone following altered accumbal DAT function may subserve a sensation-seeker phenotype and the vulnerability to impulse-control disorders.


Assuntos
Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Comportamento Impulsivo/genética , Comportamento Impulsivo/fisiopatologia , Núcleo Accumbens/metabolismo , Análise de Variância , Animais , Comportamento de Escolha/fisiologia , Condicionamento Operante , Proteínas da Membrana Plasmática de Transporte de Dopamina/genética , Comportamento Exploratório/fisiologia , Regulação da Expressão Gênica/genética , Proteínas de Fluorescência Verde/genética , Lentivirus/metabolismo , Masculino , Mutação/genética , Probabilidade , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Wistar , Recompensa , Assunção de Riscos , Estatística como Assunto
11.
J Chem Phys ; 130(3): 034505, 2009 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-19173529

RESUMO

Mode-selective vibrational redistribution after spectrally selective excitation within the highly structured N-H stretching band of the 7-azaindole dimer was observed by subpicosecond infrared-pump/anti-Stokes Raman-probe spectroscopy. Measurements after relaxation of the N-H stretching vibration indicate ultrafast initial population transfer to vibrations with pronounced N-H bending character. From these modes energy is transferred to modes of frequencies below 1000 cm(-1) on a slower time scale of about 3 ps. Tuning the spectrally narrow infrared excitation to the different substructures of the N-H stretching band influences the distribution of populations between the fingerprint modes. Their relative populations are correlated with the contributions of the modes forming the different coupled combination tones of the N-H stretching band. These results provide experimental support to a Fermi resonance model previously used for simulations of the N-H stretching infrared absorption band shape and insight into relaxation from the initially excited combination bands.


Assuntos
Ligação de Hidrogênio , Hidrogênio/química , Nitrogênio/química , Análise Espectral Raman/métodos , Físico-Química/métodos , DNA/química , Dimerização , Luz , Modelos Teóricos , Espalhamento de Radiação , Software , Espectrofotometria/métodos , Fatores de Tempo
12.
Genes Brain Behav ; 7(2): 244-56, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17680802

RESUMO

Urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) are extracellular proteases that play a role in synaptic plasticity and remodeling. Psychostimulants induce both tPA and uPA in acute and chronic drug delivery, but cocaine induces preferentially uPA, whereas morphine and amphetamine induce preferentially tPA. Specific doxycline-regulatable lentiviruses expressing these extracellular proteases have been prepared and stereotaxically injected into the nucleus accumbens. We show that tPA-overexpressing animals show greater locomotor activity and behavioral sensitization upon morphine and amphetamine treatments. These effects could be fully suppressed by doxycycline or when tPA had been silenced using small interfering RNAs (siRNAs)-expressing lentiviruses. Furthermore, animals infected with lentiviruses expressing uPA show enhanced conditional place preference for cocaine compared with tPA-overexpressing animals. In contrast, tPA-overexpressing animals when administered amphetamine or morphine showed greater place preference compared with uPA-overexpressing animals. The effects are suppressed when tPA has been silenced using specific siRNAs-expressing vectors. Tissue-type plasminogen activator and uPA possibly induce distinct behaviors, which may be interpreted according to their differential pattern of activation and downstream targets. Taken together, these data add further evidence for a significant function of extracellular proteases tPA and uPA in addiction and suggest a differential role of plasminogen activators in this context.


Assuntos
Anfetamina/farmacologia , Comportamento Animal/fisiologia , Cocaína/farmacologia , Doxiciclina/farmacologia , Morfina/farmacologia , Núcleo Accumbens/fisiologia , Ativadores de Plasminogênio/genética , Recompensa , Ativador de Plasminogênio Tecidual/genética , Animais , Sequência de Bases , Comportamento Animal/efeitos dos fármacos , Primers do DNA , Lentivirus/efeitos dos fármacos , Lentivirus/genética , Masculino , Dados de Sequência Molecular , Núcleo Accumbens/efeitos dos fármacos , Reação em Cadeia da Polimerase , RNA Interferente Pequeno/genética , RNA Viral/genética , Ratos , Ratos Wistar , Proteínas Virais/genética
13.
J Chem Phys ; 127(23): 234505, 2007 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-18154398

RESUMO

Applying a combined experimental and theoretical approach we demonstrate that doublets of the nu(s)(NO(2)) band of 4-nitroaniline which have been observed in several environments originate from Fermi resonances. Changes of the line shapes typical for Fermi resonances are reported also for other isotopomers of 4-nitroaniline, however, for each of them in different solvents and solvent mixtures. Simulations of the infrared spectra based on the solvatochromic frequency shifts of the nu(s)(NO(2)) vibration determined experimentally together with calculated cubic couplings with overtones and combination bands account for the experimental findings.


Assuntos
Compostos de Anilina/química , Solventes/química , Espectrofotometria Infravermelho/métodos , Vibração
14.
Phys Rev Lett ; 98(24): 248301, 2007 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-17677998

RESUMO

Femtosecond photoexcitation of organic chromophores in a molecular crystal induces strong changes of the electronic dipole moment via intramolecular charge transfer as is evident from transient vibrational spectra. The structural response of the crystal to the dipole change is mapped directly for the first time by ultrafast x-ray diffraction or diffuse scattering. Changes of diffracted and transmitted x-ray intensity demonstrate an angular rearrangement of molecules around excited dipoles following the 10 ps kinetics of charge transfer and leaving lattice plane spacings unchanged. Transient x-ray scattering is governed by solvation, masking changes of the chromophore molecular structure.


Assuntos
Cristalização , Modelos Químicos , Soluções/química , Modelos Moleculares , Nitrilas/química , Difração de Raios X
15.
Phys Rev Lett ; 97(22): 221101, 2006 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-17155787

RESUMO

On 27 December 2004, a giant gamma flare from the Soft Gamma-Ray Repeater 1806-20 saturated many satellite gamma-ray detectors, being the brightest transient event ever observed in the Galaxy. AMANDA-II was used to search for down-going muons indicative of high-energy gammas and/or neutrinos from this object. The data revealed no significant signal, so upper limits (at 90% C.L.) on the normalization constant were set: 0.05(0.5) TeV-1 m;{-2} s;{-1} for gamma=-1.47 (-2) in the gamma flux and 0.4(6.1) TeV-1 m;{-2} s;{-1} for gamma=-1.47 (-2) in the high-energy neutrino flux.

17.
Phys Rev Lett ; 95(14): 147402, 2005 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-16241692

RESUMO

The multilevel structure and vibrational couplings of O-H stretching transitions in intermolecular hydrogen bonds of acetic acid dimers are determined by femtosecond two-dimensional photon-echo spectroscopy in the infrared. Combining experiment and theoretical calculations, we separate Fermi resonances with combination tones of fingerprint modes from anharmonic couplings to underdamped low-frequency modes of the dimer. A multilevel density matrix approach based on density functional theory calculations reproduces the experimental results and reveals coupling strengths of both mechanisms on the order of 40-150 cm(-1).

18.
Mar Environ Res ; 59(4): 367-80, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15589987

RESUMO

When Hurricane Iniki struck the Hawaiian Islands in September 1992, it provided a rare opportunity to examine the immediate effects of a hurricane on two intertidal benthic communities off the reefs of O'ahu, Hawai'i. The Niu Beach site contained large, obvious aggregations of the tube building polychaete Diopatra dexiognatha, and the Wailupe Beach site was without obvious tubiculous fauna at the surface. Ten replicate sediment cores were taken before and after the hurricane with a 7.6 cm PVC corer and organisms were identified to family and enumerated. There were no substantial depletions or loss of taxa after the hurricane. Oligochaetes were the most dominant taxa pre-and post-hurricane. The abundance of all dominant polychaete families increased post-hurricane. The three most abundant polychaetes were capitellids and D. dexiognatha (Onuphidae) at Niu Beach and Pygospio muscularis (Spionidae) at Wailupe Beach. We suggest that D. dexiognatha and P. muscularis help stabilize the sediments since they both form dense tube mats while capitellids and oligochaetes are considered highly adaptive surface burrowers that can take advantage of newly disturbed sediments. Overall, there was no substantial effect observed on the intertidal fauna exposed to this severe disturbance. It is suggested here that invertebrate communities in this area are adapted to survive and thrive in high-energy environments and possibly benefit from dense aggregations of tube building polychaetes.


Assuntos
Desastres , Poliquetos/crescimento & desenvolvimento , Animais , Classificação , Ecossistema , Sedimentos Geológicos , Havaí , Dinâmica Populacional
20.
JAMA ; 286(15): 1841-8, 2001 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-11597285

RESUMO

CONTEXT: High levels of variation and inefficiency exist in current clinical practice regarding use of cervical spine (C-spine) radiography in alert and stable trauma patients. OBJECTIVE: To derive a clinical decision rule that is highly sensitive for detecting acute C-spine injury and will allow emergency department (ED) physicians to be more selective in use of radiography in alert and stable trauma patients. DESIGN: Prospective cohort study conducted from October 1996 to April 1999, in which physicians evaluated patients for 20 standardized clinical findings prior to radiography. In some cases, a second physician performed independent interobserver assessments. SETTING: Ten EDs in large Canadian community and university hospitals. PATIENTS: Convenience sample of 8924 adults (mean age, 37 years) who presented to the ED with blunt trauma to the head/neck, stable vital signs, and a Glasgow Coma Scale score of 15. MAIN OUTCOME MEASURE: Clinically important C-spine injury, evaluated by plain radiography, computed tomography, and a structured follow-up telephone interview. The clinical decision rule was derived using the kappa coefficient, logistic regression analysis, and chi(2) recursive partitioning techniques. RESULTS: Among the study sample, 151 (1.7%) had important C-spine injury. The resultant model and final Canadian C-Spine Rule comprises 3 main questions: (1) is there any high-risk factor present that mandates radiography (ie, age >/=65 years, dangerous mechanism, or paresthesias in extremities)? (2) is there any low-risk factor present that allows safe assessment of range of motion (ie, simple rear-end motor vehicle collision, sitting position in ED, ambulatory at any time since injury, delayed onset of neck pain, or absence of midline C-spine tenderness)? and (3) is the patient able to actively rotate neck 45 degrees to the left and right? By cross-validation, this rule had 100% sensitivity (95% confidence interval [CI], 98%-100%) and 42.5% specificity (95% CI, 40%-44%) for identifying 151 clinically important C-spine injuries. The potential radiography ordering rate would be 58.2%. CONCLUSION: We have derived the Canadian C-Spine Rule, a highly sensitive decision rule for use of C-spine radiography in alert and stable trauma patients. If prospectively validated in other cohorts, this rule has the potential to significantly reduce practice variation and inefficiency in ED use of C-spine radiography.


Assuntos
Traumatismos Craniocerebrais/diagnóstico por imagem , Técnicas de Apoio para a Decisão , Serviços Médicos de Emergência/normas , Lesões do Pescoço/diagnóstico por imagem , Traumatologia/normas , Ferimentos não Penetrantes/diagnóstico por imagem , Adulto , Idoso , Canadá , Vértebras Cervicais/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Processos e Resultados em Cuidados de Saúde , Estudos Prospectivos , Radiografia/normas , Análise de Regressão , Medição de Risco , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X
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