Infrared Jntensities of Liquids IV: Recent Measurements of Infrared Optical Constants and Absolute Infrared Absorption Intensities of Liquids by Multiple Attenuated Total Reflectance

Recent refinements are described to the CIRCLE, multiple attenuated total reflection method for measuring infrared optical and dielectric constants, absolute integrated intensities and, hence, molecular dipole derivatives. Attention is focussed on the accuracy of the method, which is estimated from measurements on H20 (1) and D20 (1).The real and imaginary optical constants agree with literature values to < 1.5% and about 6%, respectively, which is about the agreement of the literature values. The integrated areas agree with literature values to < 2%, and OH and OD bond dipole derivatives for H20 and D20 agree to < 10f0. pATR, refractive index, dielectric constant, and absorption cross section spectra are reported from 8000to 350 cm? for 2-butanol, and integrated absolute absorption intensities and bond dipole derivatives are presented for 2-butanol, 2-hexanol, and 2-octanol and compared with those for primary alcohols and water

Infrared Jntensities of Liquids IV: Recent Measurements of Infrared Optical Constants and Absolute Infrared Absorption Intensities of Liquids by Multiple Attenuated Total Reflectance

Recent refinements are described to the CIRCLE, multiple attenuated total reflection method for measuring infrared optical and dielectric constants, absolute integrated intensities and, hence, molecular dipole derivatives. Attention is focussed on the accuracy of the method, which is estimated from measurements on H20 (1) and D20 (1).The real and imaginary optical constants agree with literature values to < 1.5% and about 6%, respectively, which is about the agreement of the literature values. The integrated areas agree with literature values to < 2%, and OH and OD bond dipole derivatives for H20 and D20 agree to < 10f0. pATR, refractive index, dielectric constant, and absorption cross section spectra are reported from 8000to 350 cm? for 2-butanol, and integrated absolute absorption intensities and bond dipole derivatives are presented for 2-butanol, 2-hexanol, and 2-octanol and compared with those for primary alcohols and water

Assessment of nerve involvement in the lumbar spine: agreement between magnetic resonance imaging, physical examination and pain drawing findings

<p>Abstract</p> <p>Background</p> <p>Detection of nerve involvement originating in the spine is a primary concern in the assessment of spine symptoms. Magnetic resonance imaging (MRI) has become the diagnostic method of choice for this detection. However, the agreement between MRI and other diagnostic methods for detecting nerve involvement has not been fully evaluated. The aim of this diagnostic study was to evaluate the agreement between nerve involvement visible in MRI and findings of nerve involvement detected in a structured physical examination and a simplified pain drawing.</p> <p>Methods</p> <p>Sixty-one consecutive patients referred for MRI of the lumbar spine were - without knowledge of MRI findings - assessed for nerve involvement with a simplified pain drawing and a structured physical examination. Agreement between findings was calculated as overall agreement, the p value for McNemar's exact test, specificity, sensitivity, and positive and negative predictive values.</p> <p>Results</p> <p>MRI-visible nerve involvement was significantly less common than, and showed weak agreement with, physical examination and pain drawing findings of nerve involvement in corresponding body segments. In spine segment L4-5, where most findings of nerve involvement were detected, the mean sensitivity of MRI-visible nerve involvement to a positive neurological test in the physical examination ranged from 16-37%. The mean specificity of MRI-visible nerve involvement in the same segment ranged from 61-77%. Positive and negative predictive values of MRI-visible nerve involvement in segment L4-5 ranged from 22-78% and 28-56% respectively.</p> <p>Conclusion</p> <p>In patients with long-standing nerve root symptoms referred for lumbar MRI, MRI-visible nerve involvement significantly underestimates the presence of nerve involvement detected by a physical examination and a pain drawing. A structured physical examination and a simplified pain drawing may reveal that many patients with "MRI-invisible" lumbar symptoms need treatment aimed at nerve involvement. Factors other than present MRI-visible nerve involvement may be responsible for findings of nerve involvement in the physical examination and the pain drawing.</p

Oxidative stress in the developing brain: effects of postnatal glucocorticoid therapy and antioxidants in the rat.

In premature infants, glucocorticoids ameliorate chronic lung disease, but have adverse effects on long-term neurological function. Glucocorticoid excess promotes free radical overproduction. We hypothesised that the adverse effects of postnatal glucocorticoid therapy on the developing brain are secondary to oxidative stress and that antioxidant treatment would diminish unwanted effects. Male rat pups received a clinically-relevant tapering course of dexamethasone (DEX; 0.5, 0.3, and 0.1 mg x kg(-1) x day(-1)), with or without antioxidant vitamins C and E (DEXCE; 200 mg x kg(-1) x day(-1) and 100 mg x kg(-1) x day(-1), respectively), on postnatal days 1-6 (P1-6). Controls received saline or saline with vitamins. At weaning, relative to controls, DEX decreased total brain volume (704.4±34.7 mm(3) vs. 564.0±20.0 mm(3)), the soma volume of neurons in the CA1 (1172.6±30.4 µm(3) vs. 1002.4±11.8 µm(3)) and in the dentate gyrus (525.9±27.2 µm(3) vs. 421.5±24.6 µm(3)) of the hippocampus, and induced oxidative stress in the cortex (protein expression: heat shock protein 70 [Hsp70]: +68%; 4-hydroxynonenal [4-HNE]: +118% and nitrotyrosine [NT]: +20%). Dexamethasone in combination with vitamins resulted in improvements in total brain volume (637.5±43.1 mm(3)), and soma volume of neurons in the CA1 (1157.5±42.4 µm(3)) and the dentate gyrus (536.1±27.2 µm(3)). Hsp70 protein expression was unaltered in the cortex (+9%), however, 4-HNE (+95%) and NT (+24%) protein expression remained upregulated. Treatment of neonates with vitamins alone induced oxidative stress in the cortex (Hsp70: +67%; 4-HNE: +73%; NT: +22%) and in the hippocampus (NT: +35%). Combined glucocorticoid and antioxidant therapy in premature infants may be safer for the developing brain than glucocorticoids alone in the treatment of chronic lung disease. However, antioxidant therapy in healthy offspring is not recommended

Raman spectra, absolute Raman intensities and electro-optical parameters of pertechnetate, perrhenate and periodate ions in aqueous solution

NRC publication: Ye

Polarized Raman spectra and intensities of aromatic amino acids phenylalanine, tyrosine and tryptophan

NRC publication: Ye

L-triangular matrices in the theory of molecular vibrations

The properties and applications of the normal coordinate transformation matrix L (S = LQ) and of its reciprocal L-1 are discussed with respect to the general parametric form L = L° R (where L° is lower triangular). An iterative computational procedure of L° and of K° = (L°)-1 is given in detail. Moreover, the application to the determination of various molecular constants is given for problems of order two

Infrared spectra of joint fluids

The present study demonstrates the application of infrared spectroscopy to the diagnosis of arthritic conditions by analysis of joint fluids. The detection of carbon dioxide clathrates, their origin and the nature of the host material is discussed. The analytical sensitivity of mid IR second derivative spectra is demonstrated with the detection of the local anaesthetic lidocaine in some of the samples. Linear discriminant analysis and hierarchical clustering are successfully used to classify the spectra according to their respective clinical diagnosis.Peer reviewed: YesNRC publication: Ye

Carbon dioxide in tissues, cells, and biological fluids detected by FTIR spectroscopy

Previous studies from this lab have demonstrated the presence of a novel absorption in infrared spectra of synovial fluid films (2337 122343 cm-1) which was suggested to arise from CO2 trapped within the organic matrix left after drying. In the present paper, we establish the presence of this absorption in a wide range of biological fluids, tissues, and cell suspensions. Results of studies with a range of common biological materials suggest that the CO2 interacts nonspecifically with the protein components of cells and fluids. Experiments with 13C-labeled glucose clearly demonstrate that this ubiquitous absorption is attributable to CO2 produced by glucose breakdown within cells, presenting the interesting possibility of monitoring cellular metabolism by infrared spectroscopy.Peer reviewed: YesNRC publication: Ye