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1.
Pediatr Cardiol ; 2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-39134678

RESUMO

To investigate the relationship between quantitative tracheal geometry and clinical course among various types of vascular ring and to identify factors correlating with symptom presentation. Patients with vascular ring diagnosed between April 2010 and December 2022 were included. All the patients were classified as type 1 (complete double aortic arch); type 2 (incomplete double aortic arch); type 3 (circumflex aorta); type 4 (right aortic arch and aberrant left subclavian artery with a left retroesophageal diverticulum of Kommerell); or type 5 (mirror-imaged right aortic arch with retroesophageal aortic diverticulum). Their clinical characteristics and quantitative variables on computed tomography (CT) were compared. Of the 50 patients enrolled, those with type 1 tended to have a smaller luminal tracheal diameter at the level of the ring. The median symptom-free survival time was shortest in this group (16.0 days [95% confidence interval (CI): 9.4-51.0]), followed by type 3 (138.0 days [95% CI: 0.0-851.4]). Type 1 (hazard ratio [HR]: 9.0; 95% CI: 2.3-35.0; P = 0.001), type 3 (HR: 4.2; 95% CI: 1.4-13.2; P = 0.013), and the percentage of tracheal narrowing in the anteroposterior projection (HR: 0.87; 95% CI: 0.78-0.96; P = 0.008) were significantly associated with symptom presentation in the time-dependent course. The aortic arch encircling the entire circumference in type 1 and high-pressure vasculature in front of the vertebral body in types 1 and 3 may contribute to raising the risk of symptom presentation.

2.
Proc Natl Acad Sci U S A ; 114(31): 8169-8174, 2017 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28716940

RESUMO

Photochemical oxidation of aromatic hydrocarbons leads to tropospheric ozone and secondary organic aerosol (SOA) formation, with profound implications for air quality, human health, and climate. Toluene is the most abundant aromatic compound under urban environments, but its detailed chemical oxidation mechanism remains uncertain. From combined laboratory experiments and quantum chemical calculations, we show a toluene oxidation mechanism that is different from the one adopted in current atmospheric models. Our experimental work indicates a larger-than-expected branching ratio for cresols, but a negligible formation of ring-opening products (e.g., methylglyoxal). Quantum chemical calculations also demonstrate that cresols are much more stable than their corresponding peroxy radicals, and, for the most favorable OH (ortho) addition, the pathway of H extraction by O2 to form the cresol proceeds with a smaller barrier than O2 addition to form the peroxy radical. Our results reveal that phenolic (rather than peroxy radical) formation represents the dominant pathway for toluene oxidation, highlighting the necessity to reassess its role in ozone and SOA formation in the atmosphere.

3.
J Phys Chem A ; 119(30): 8261-8, 2015 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-26126155

RESUMO

Addition reaction of a radical to the double bond of a monomer, which is important at early stage of photopolymerization, has been studied by time-resolved (TR-) and pulsed electron paramagnetic resonance (EPR) spectroscopic methods. Reactions of one phosphorus-centered and three carbon-centered radicals attacking to several monomers have been employed. Intermediate radicals were identified by analyzing the recorded TR-EPR spectra, and the reaction rate constants were determined by the electron spin-echo detection method proposed by Weber and Turro [J. Phys. Chem. A, 2003, 107 (18), 3326 - 3334]. The quantum chemical calculation shows that the rate constants for the addition reactions are well-explained by introducing two factors of "enthalpy effect" and "polar effect" to control the activation barrier height. It was observed that the rate constants of the phosphorus-centered radical were larger than those of carbon-centered radicals for some monomers. The difference in the rate constants was argued on the basis of frequency factor and activation barrier both of which are influenced by an atom of radical center.

4.
J Phys Chem A ; 118(18): 3280-7, 2014 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-24724531

RESUMO

Several protic ionic liquids (PILs) with a wide range of pK(a) differences (ΔpK(a)) between the parent acid and base molecules were thermally evaporated in vacuum, trapped on a CsI plate by a cryogenic neon matrix-isolation method, and studied by Fourier transform infrared spectroscopy and density functional theory calculations. The parent neutral molecules and proton-transferred cation-anion pair species were identified as chemical components evaporated from the PILs with lower and higher ΔpK(a) values, respectively. The ΔpK(a)-dependent vaporization mechanism is discussed in terms of thermodynamic equilibrium between acid-base and anion-cation systems in the liquid phase.

5.
J Phys Chem A ; 117(49): 13105-11, 2013 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-24252115

RESUMO

The photochemistry of ozone-water complexes and the wavelength dependence of the reactions were studied by matrix isolation FTIR spectrometry in neon, argon, and krypton matrixes. Hydrogen peroxide was formed upon the irradiation of UV light below 355 nm. Quantitative analyses of the reactant and product were performed to evaluate the matrix cage effect of the photoreaction. In argon and krypton matrixes, a bimolecular O((1)D) + H2O → H2O2 reaction was found to occur to form hydrogen peroxide, where the O((1)D) atom generated by the photolysis of ozone diffused in the cryogenic solids to encounter water. In a neon matrix, hydrogen peroxide was generated through intracage photoreaction of the ozone-water complex, indicating that a neon matrix medium is most appropriate to study the photochemistry of the ozone-water complex.

6.
J Phys Chem A ; 117(7): 1420-7, 2013 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-23350665

RESUMO

The np gerade Rydberg states of acetylene were analyzed using two-photon resonance fluorescence excitation spectroscopy in the 72,000-93,000 cm(-1) energy region. The npπ(1)Σ(g)(+) and npπ(1)Δ(g) Rydberg series (n = 3-5) were identified in the fluorescence excitation spectrum measured by monitoring the C(2) d(3)Π(g)-a(3)Π(u) Swan system. Some vibronic bands were assigned to the npπ(1)Δ(g)-X̃(1)Σ(g)(+) transition on the basis of rotational analysis. The 5pσ(1)Π(g) state was observed, which is the first such observation in an npσ(1)Π(g) series. Rotational analysis of the 5pσ(1)Π(g)-X̃(1)Σ(g)(+) transition showed e/f-symmetry dependent predissociation of acetylene in the 5pσ(1)Π(g) state. The 0(0)(0) band of the deuterated acetylene (C(2)D(2)) 4pπ(1)Σ(g)(+)-X̃(1)Σ(g)(+) transition exhibits an atypical structure, which was satisfactorily reproduced by a simple model of quantum interference between the discrete and quasi-continuum states. The predissociative lifetimes of the npπgerade Rydberg states were estimated from the spectral profiles. The predissociation mechanism of acetylene in the Rydberg states is discussed.

7.
J Phys Chem A ; 116(9): 2032-8, 2012 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-22309165

RESUMO

Collision-induced near-IR emission of O(2) a(1)Δ(g) was investigated in O(2)/M (M = Ar, Kr, Xe, N(2), or CO(2)) gas mixtures, where the total pressure ranged from 10 to 100 atm, and gaseous O(2) dimol was excited with a pulsed dye laser at 630 nm through the simultaneous two-electron transition to prepare O(2) in the a(1)Δ(g) state. The a(1)Δ(g) → X(3)Σ(g)(-) emission intensity around 1270 nm increased with the number density of foreign gas (M) under constant O(2) number density. Emission enhancement efficiencies were in the order Xe > CO(2) > O(2) > Kr > N(2) > Ar; they are controlled by collisional enhancement during the near-IR emission at 1270 nm but not during photoabsorption at 630 nm. Efficiencies were converted into bimolecular rate constants to enhance the radiative a → X transition for the added gases. The rate constants were estimated as quadratically dependent on the molar refraction (or polarizability) of collision gas. The self-quenching rate constant was determined from the Stern-Volmer plot of the emission lifetimes measured in pure O(2).

8.
J Phys Chem A ; 115(24): 6347-56, 2011 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-21574586

RESUMO

Rotational motion of a nitroxide radical, peroxylamine disulfonate (PADS), dissolved in room temperature ionic liquids (RTILs) was studied by analyzing electron paramagnetic resonance spectra of PADS in various RTILs. We determined physical properties of PADS such as the hyperfine coupling constant (A), the temperature dependence of anisotropic rotational correlation times (τ(∥) and τ(⊥)), and rotational anisotropy (N). We observed that the A values remain unchanged for various RTILs, which indicates negligible interaction between the N-O PADS group and the cation of RTIL. Large N values suggest strong interaction of the negative sulfonyl parts of PADS with the cations of RTILs. Most of the τ(∥), τ(⊥), and (τ(∥)τ(⊥))(1/2) values are within the range calculated on the basis of a hydrodynamic theory with stick and slip boundary conditions. It was deduced that this theory could not adequately explain the measured results in some RTILs with smaller BF(4) and PF(6) anions.


Assuntos
Aminas/química , Líquidos Iônicos/química , Peróxidos/química , Teoria Quântica , Temperatura , Difusão , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Rotação , Solubilidade
9.
J Phys Chem A ; 114(48): 12662-6, 2010 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-21069996

RESUMO

The matrix-isolation infrared spectrum of a thermally evaporated ionic liquid, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([Emim][OTf]), was measured by FTIR spectroscopy and analyzed with the aid of DFT calculations. The main chemical species in the observed IR spectrum was mainly identified as the 1:1 cation-anion pair, which corresponds to the second stable ion-pair structure bonded through five hydrogen bonds between three O atoms of the anion side and four H atoms of the cation.


Assuntos
Imidazóis/química , Líquidos Iônicos/química , Mesilatos/química , Teoria Quântica , Ligação de Hidrogênio , Íons/química , Estrutura Molecular , Espectroscopia de Infravermelho com Transformada de Fourier , Volatilização
10.
J Phys Chem B ; 113(14): 4756-62, 2009 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-19281187

RESUMO

Low-temperature infrared spectra of thermally evaporated ionic liquids, 1-ethyl- and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and bis(trifluoromethanesulfonyl)amide have been measured in a cryogenic Ne matrix. The experimental IR spectrum of bis(trifluoromethanesulfonyl)amide can be reproduced theoretically by not B3LYP/6-31G* but MP2/6-31G* calculation, which suggests that the vibrational analysis for ionic liquids composed of bis(trifluoromethanesulfonyl)imide anion would be more successfully performed using the MP2 calculation. By comparison of the matrix-isolation spectra of the ionic liquids with the MP2 calculation, their geometrical structures in the gas phase are determined to be of C(2-position)-H(+)...N(-) interaction structure, which corresponds to the geometry of the energetically second-lowest ion-pair structure. The present study may provide a valuable clue to understand a vaporization mechanism of ionic liquid.


Assuntos
Imidazóis/química , Líquidos Iônicos/química , Sulfonamidas/química , Ânions/química , Cátions/química , Simulação por Computador , Gases/química , Modelos Químicos , Estrutura Molecular , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
11.
J Phys Chem A ; 113(37): 9945-51, 2009 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-19689151

RESUMO

Infrared spectra of OH-(H2O)n (n = 1, 2) isolated in solid Ne were measured by FT-IR spectroscopy. Complexes of OH-(H2O)n were prepared by vacuum ultraviolet (VUV) photolysis of water clusters, and the OH radical stretch and HOH bending vibrations of OH-H2O and OH-(H2O)2 complexes were identified with the aid of quantum chemical calculations. Observation of the recombination reaction OH-H2O + H --> (H2O)2 under dark conditions provides undisputed evidence for our spectroscopic assignment. Quantum chemical calculations predict the cyclic structure to be the most stable for OH-(H2O)2 and OH-(H2O)3. The strength of the hydrogen bond within OH-(H2O)n depends on cluster size.


Assuntos
Radical Hidroxila/química , Modelos Químicos , Teoria Quântica , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química , Ligação de Hidrogênio , Vibração
12.
Restor Dent Endod ; 44(4): e45, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31799172

RESUMO

OBJECTIVES: Self-adhesive resin cements contain functional monomers that enable them to adhere to the tooth structure without a separate adhesive or etchant. One of the most stable functional monomers used for chemical bonding to calcium in hydroxyapatite is 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP). The aim of this study was to evaluate the influence of the10-MDP concentration on the bond strength and physical properties of self-adhesive resin cements. MATERIALS AND METHODS: We used experimental resin cements containing 3 different concentrations of 10-MDP: 3.3 wt% (RC1), 6.6 wt% (RC2), or 9.9 wt% (RC3). The micro-tensile bond strength of each resin cement to dentin and a hybrid resin block (Estenia C&B, Kuraray Noritake Dental) was measured, and the fractured surface morphology was analyzed. Further, the flexural strength of the resin cements was measured using the three-point bending test. The water sorption and solubility of the cements following 30 days of immersion in water were measured. RESULTS: The bond strength of RC2 was significantly higher than that of RC1. There was no significant difference between the bond strength of RC2 and that of RC3. The water sorption of RC3 was higher than that of any other cement. There were no significant differences in the three-point bending strength or water solubility among all three types of cements. CONCLUSIONS: Within the limitations of this study, it is suggested that 6.6 wt% 10-MDP showed superior properties than 3.3 wt% or 9.9 wt% 10-MDP in self-adhesive resin cement.

13.
Nihon Rinsho Meneki Gakkai Kaishi ; 40(2): 124-130, 2017.
Artigo em Japonês | MEDLINE | ID: mdl-28603203

RESUMO

Neonatal lupus (NL), a passively-acquired autoimmune disease associated with maternal anti-SSA antibody, presents both cardiac manifestations such as cardiac NL and non-cardiac manifestations including rashes, cytopenia, and hepatic abnormalities. Cardiac NL, occurring in 1-2% of anti-SS-A antibody-positive mothers, is a life-threatening complication with a mortality rate of 20% and a pacemaker implantation rate of 70%. In contrast, cutaneous NL, which is more common than cardiac NL, usually resolves in six months. Since half of NL cases occur in asymptomatic mothers, if an infant presents characteristic cutaneous or cardiac manifestations of NL, the mother should be tested for anti-SS-A antibody. In mothers positive for anti-SS-A antibody, the risk of having a child with cardiac NL increases ten-fold and five-fold for a previous child with cardiac NL and cutaneous NL, respectively. A joint American, British, and French retrospective study of NL registries showed that hydroxychloroquine (HCQ) reduced the cardiac NL risk in subsequent pregnancies in mothers who previously had a child with cardiac NL. A prospective open-label study to confirm this effect is being undertaken in the USA. A similar prospective multi-center study will be undertaken in Japan. Establishing a Japanese registry of children with NL and subsequent pregnancies of their mothers will help promote clinical research in NL in Japan.


Assuntos
Lúpus Eritematoso Sistêmico/congênito , Anticorpos Antinucleares/sangue , Autoanticorpos/sangue , Biomarcadores/sangue , Feminino , Humanos , Hidroxicloroquina/administração & dosagem , Recém-Nascido , Lúpus Eritematoso Cutâneo/diagnóstico , Lúpus Eritematoso Sistêmico/diagnóstico , Lúpus Eritematoso Sistêmico/epidemiologia , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/prevenção & controle , Gravidez , Estudos Prospectivos , Sistema de Registros , Estudos Retrospectivos , Risco
14.
Int J Oncol ; 47(1): 211-9, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25955490

RESUMO

Previously, we found that the injection of zoledronic acid (ZOL) into mice bearing tumor induced changes of the vascular structure in the tumor. In this study, we examined whether ZOL treatment could decrease interstitial fluid pressure (IFP) via change of tumor vasculature, and enhance the antitumor efficacy of liposomal doxorubicin (Doxil®). When ZOL solution was injected at 40 µg/mouse per day for three consecutive days into mice bearing murine Lewis lung carcinoma LLC tumor, depletion of macrophages in tumor tissue and decreased density of tumor vasculature were observed. Furthermore, ZOL treatments induced inflammatory cytokines such as interleukin (IL)-10 and -12, granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor (TNF)-α in serum of LLC tumor-bearing mice, but not in normal mice, indicating that ZOL treatments might induce an inflammatory response in tumor tissue. Furthermore, ZOL treatments increased antitumor activity by Doxil in mice bearing a subcutaneous LLC tumor, although they did not significantly increase the tumor accumulation of doxorubicin (DXR). These results suggest that ZOL treatments might increase the therapeutic efficacy of Doxil via improvement of DXR distribution in a tumor by changing the tumor vasculature. ZOL treatment can be an alternative approach to increase the antitumor effect of liposomal drugs.


Assuntos
Antibióticos Antineoplásicos/administração & dosagem , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Difosfonatos/administração & dosagem , Doxorrubicina/análogos & derivados , Líquido Extracelular/efeitos dos fármacos , Imidazóis/administração & dosagem , Animais , Antibióticos Antineoplásicos/uso terapêutico , Carcinoma Pulmonar de Lewis/genética , Carcinoma Pulmonar de Lewis/imunologia , Linhagem Celular Tumoral , Citocinas/sangue , Citocinas/genética , Difosfonatos/farmacologia , Doxorrubicina/administração & dosagem , Doxorrubicina/uso terapêutico , Sinergismo Farmacológico , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Imidazóis/farmacologia , Macrófagos/efeitos dos fármacos , Camundongos , Polietilenoglicóis/administração & dosagem , Polietilenoglicóis/uso terapêutico , Ácido Zoledrônico
15.
PLoS One ; 10(5): e0128189, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26010099

RESUMO

Kawasaki disease (KD), an acute vasculitis that preferentially affects coronary arteries, is still the leading cause of acquired heart disease in children. Although the involvement of immune system malfunction in the onset of KD is suggested, its etiology still remains to be clarified. We investigated autoantibodies in KD patients, which are frequently found in sera from patients with autoimmune diseases, vasculitides and arteritides. We performed two-dimensional western blotting and LC-MS/MS to analyze the antigens of autoantibodies, detected two protein spots with 4 out of 24 sera from KD patients but not with 6 control sera, and identified the antigens as 4-trimethylaminobutyraldehyde dehydrogenase (TMABA-DH). A slot blot analysis with TMABA-DH as an antigen also revealed higher reactivities of patients' sera than control sera (positive rates: 18/43 vs 3/41). Using an enzyme-linked immunosorbent assay (ELISA), we found that the reactivity of anti-TMABA-DH antibodies in sera from KD patients was significantly higher than that in sera from age-matched controls. The optimal cut-off value of 0.043 had a sensitivity of 83.7% and a specificity of 80.0% in detecting KD patients (positive rates: 37/43 for KD patients, 9/41 for controls). Immunohistochemistry performed on thin sections of rat heart revealed that TMABA-DH colocalized with myosin light chains in cardiac myocytes. Patient sera with high reactivity gave similar immunostaining pattern. These results suggest that the detection of anti-TMABA-DH autoantibody could be a potential strategy for a diagnosis of KD.


Assuntos
Aldeído Oxirredutases/imunologia , Autoanticorpos/imunologia , Autoantígenos/imunologia , Síndrome de Linfonodos Mucocutâneos/imunologia , Miócitos Cardíacos/imunologia , Aldeído Oxirredutases/sangue , Animais , Autoanticorpos/sangue , Autoantígenos/sangue , Criança , Pré-Escolar , Feminino , Células HEK293 , Células Endoteliais da Veia Umbilical Humana , Humanos , Lactente , Masculino , Síndrome de Linfonodos Mucocutâneos/sangue , Síndrome de Linfonodos Mucocutâneos/diagnóstico , Miócitos Cardíacos/metabolismo , Cadeias Leves de Miosina/imunologia , Cadeias Leves de Miosina/metabolismo , Ratos
16.
Surgery ; 132(1): 86-92, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12110800

RESUMO

BACKGROUND: The purpose of this study was to clarify the still poorly understood dynamics of peritoneal inflammatory cells (PICs) in acute pancreatitis. METHODS: Acute pancreatitis of 3 different degrees of severity was induced in male Wistar rats. Peritoneal lavage was performed at 1, 6, 12, and 24 hours after the induction, and the fluids collected were analyzed for the number and subpopulation of PICs. The levels of apoptosis and necrosis, cytokines, and bacterial infection were also investigated. RESULTS: The number of PICs was increased in mild and moderate pancreatitis, and the infiltration of inflammatory cells had occurred. In severe pancreatitis, the number of PICs increased until 6 hours after the induction, but thereafter the number decreased. Infiltration of neutrophils occurred 6 hours after the induction, but it was not sustained thereafter and infiltration of peritoneal macrophages did not occur. Cytokines in the lavage fluid increased in all 3 models during the first 6 hours after the induction. Subsequently, cytokines were reduced in mild and moderate pancreatitis but significantly increased in severe pancreatitis. The level of bacterial infection increased according to the severity. CONCLUSIONS: The relationship between the PIC dynamics and cytokine levels in severe pancreatitis is very different from that observed in mild or moderate pancreatitis.


Assuntos
Interleucina-1/análise , Macrófagos Peritoneais/patologia , Neutrófilos/patologia , Pancreatite/patologia , Fator de Necrose Tumoral alfa/análise , Doença Aguda , Animais , Líquido Ascítico/química , Líquido Ascítico/patologia , Contagem de Células , Citometria de Fluxo , Macrófagos Peritoneais/metabolismo , Masculino , Neutrófilos/metabolismo , Pâncreas/patologia , Pancreatite/metabolismo , Pancreatite/fisiopatologia , Lavagem Peritoneal , Peritônio/patologia , Ratos , Ratos Wistar
17.
Echocardiography ; 15(2): 121-126, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11175020

RESUMO

Ultrasonic tissue characterization by integrated backscatter is a sensitive tool to detect myocardial changes related to specific diseases. Cardiotoxicity related to doxorubicin use is well known and remains a major concern. To determine if ultrasonic tissue characterization of the myocardium is abnormal in patients receiving doxorubicin, we studied the myocardium of pediatric patients receiving doxorubicin by a real-time integrated backscatter (IB) imaging system. Three values of IB parameters were averaged from the left ventricular posterior wall at the level of the tip of the mitral valve. In addition to standard echo parameters, we obtained the following IB parameters: peak, nadir, cyclic variation (CV), end-diastole, heart-rate corrected delay of nadir (Delay(c)), and the ratio of CV over end-diastole. IB parameters were normalized as Z scores from multiple linear regression equations including echo wall thickness and functional indices from a normal control group of 72 children. We evaluated 27 patients at a median age of 11.6 years (1.6 years to 20.3 years) and median time of 1.7 m (2 days to 7.2 years) after a mean cumulative dose of doxorubicin of 188 +/- 120 mg/m(2) for treatment of neoplasm. Mean (+/-SD) Z scores for IB variables were as follows: zPeak 0.15 +/- 1.07, P = 0.47; zNadir 0.41 +/- 1.16, P = 0.08; zCV -0.49 +/- 0.95, P = 0.01; zEnd-diastole 0.17 +/- 0.94, P = 0.38; zDelay(c) 0.33 +/- 0.80, P = 0.06, and zCV/Peak -0.59 +/- 1.06, P = 0.009. This study shows that ultrasonic IB of the myocardium of children receiving doxorubicin is abnormal and is independent of the cumulative dosage of doxorubicin or the amount of time since the last dose.

18.
Echocardiography ; 15(4): 353-362, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-11175048

RESUMO

Normal values in adults for ultrasonic tissue characterization by integrated backscatter have been reported previously and subsequently applied to patients with specific diseases. Factors influencing integrated backscatter values in a pediatric population are not clearly defined. To obtain normal values for myocardial ultrasonic integrated backscatter in a pediatric population, we studied 72 children with normal cardiac anatomy using an ultrasonic integrated backscatter imaging system. The parameters measured were at peak, nadir, and end-diastole in eight different regions with two different settings: fixed and variable. We subsequently calculated cyclic variation, the ratios of cyclic variation to end-diastole and to peak. Age ranged from 1 day to 17.4 years (median 4.4 years). More than 90% of data curves from the two regions in the left ventricular posterior wall in long-axis view had normal patterns, whereas more than 50% of curves for the other regions had abnormal patterns. Comparing the two posterior wall positions, there were no differences in cyclic variation between the two regions, with little effect of setting. Less effect of regions and settings was noted for the ratios of cyclic variation to end-diastole or peak. There was no relation between backscatter variables and age, gender, or height, and some variables correlated weakly with body surface area. The assessment of integrated backscatter in children is optimal with interrogation of the left ventricular posterior wall imaged in the long-axis view. More stable estimates are obtained when the cyclic variation is related to the peak or end-diastolic value.

20.
J Phys Chem B ; 117(28): 8547-54, 2013 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-23789875

RESUMO

The charge-transfer (CT) absorption bands of ion pairs composed of 1-ethylpyridinium (Epy(+)) and halogen anions (X(-): Cl, Br, or I) were measured in dichloromethane solutions of EpyX. The CT band of the Epy(+)I(-) ion pair shows clear splitting because of spin-orbit interaction in the excited state. The CT transition energy of an Epy(+)X(-) ion pair in a dichloromethane solution is related to electron affinity of X, which is in accordance with the Mulliken theory for CT bands. Extinction coefficients for the CT bands of the Epy(+)X(-) ion pairs in dichloromethane were determined using the measured absorbance, and the ion-pair concentration was estimated on the basis of electroconductivity. Structures of Epy(+)X(-) ion pairs were also evaluated on the basis of both quantum-chemical calculations and NMR spectroscopy. In addition, in the absorption spectrum measured for neat EpyI liquid, a broad band appeared at a longer wavelength side of the S1(ππ*) band. This new band has been assigned to the CT band of the Epy(+)I(-) ion pair formed in neat EpyI liquid.

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