Characterization of edible oils,butters and margarines by Fourier transform infrared spectroscopy with attenuated total reflectance

The combination of attenuated total reflectance (ATR) and mid-infrared spectroscopy (MIRS) with statistical multidimensional techniques made it possible to extract relevant information from MIR spectra of lipid-rich food products. Wavenumber assignments for typical functional groups in fatty acids were made for standard fatty acids: Absorption bands around 1745 cm⁻¹, 2853 cm⁻¹, 2954 cm⁻¹, 3005 cm⁻¹, 966 cm⁻¹, 3450 cm⁻¹ and 1640 cm⁻¹ are due to absorption of the carbonyl group, C−H stretch, =CH double bonds of lipids and O−H of lipids, respectively. In lipid-rich food products, some bands are modified. Water strongly absorbs in the region of 3600–3000 cm⁻¹ and at 1650 cm⁻¹ in butters and margarines, allowing one to rapidly differentiate the foods as function of their water content. Principal component analysis was used to emphasize the differences between spectra and to rapidly classify 27 commercial samples of oils, butters and margarines. As the MIR spectra contain information about carbonyl groups and double bonds, the foods were classified with ATR-MIR, in agreement with their degree of esterification and their degree of unsaturation as determined from gas-liquid chromatography analysis. However, it was difficult to differentiate the studied food products in terms of their average chainlength.     

Glucose plus insulin infusion improves cerebral outcome after asphyxial cardiac arrest

Hyperglycemia before ischemia worsens cerebral outcome. The aim of this study was to determine the cerebral effects of giving glucose with or without insulin after asphyxial cardiac arrest. Rats underwent 8 min of asphyxial cardiac arrest. After arrest, Group 1 received NaCl; Group 2, insulin; Group 3, glucose; and Group 4, glucose plus insulin, all intravenously. Neurological deficit (ND) scores were 14+/-10%, 22+/-12%, 12+/-10% and 2+/-2% in Groups 1-4, respectively, 72 h after reperfusion. Overall histological damage (HD) scores were 4, 2, 3 and 1, respectively. Group 4 fared significantly better than group 1 on both scores. Glucose after asphyxial cardiac arrest in rats produces no increased brain damage while glucose plus insulin improves cerebral outcome.     

A thermohydrodynamic solution for finite journal bearings under dynamic loading conditions

A numerical solution is developed for the equations governing the thermohydrodynamic flow in a finite journal bearing. Both wedge and squeeze pressure contributions are considered. Lubricant viscosity is taken as a function of the temperature distribution in the fluid film. Computer programs are devised to obtain numerical solutions for the prescribed journal centre locus. Thermal effects are shown to be pronounced in laminar flow bearing under dynamic loading conditions.     

Enzyme-assisted extraction of chicken skin protein hydrolysates and fat: Degree of hydrolysis affects the physicochemical and functional properties

Enzyme-assisted extraction (EAE) of oils/fats involves the disruption of the cell wall of source material using enzymes to facilitate the release of oil. When proteases are used as the enzyme, EAE ends in the extracted oil as well as the protein hydrolysates. Herein, the EAE (using a commercial protease, Alcalase) was exploited to obtain fat and protein hydrolysates from chicken skin. Degree of hydrolysis (DH, the percentage ratio of cleaved peptide bonds), which showed a logarithmic correlation with the reaction time, was found to affect the properties of the products. As the DH increased, the peptide chain length of protein hydrolysates decreased which was confirmed by SDS-PAGE analysis. With the increase of DH, the emulsifying activity index, foaming capacity, and oil holding capacity of the hydrolysates decreased but the solubility and emulsion stability index increased (p < 0.05). The DPPH free radical scavenging activity of the hydrolysates increased with the DH up to DH = 39.62% but decreased thereafter (p < 0.05). EAE resulted in a rise in fat yield and the fat contained a higher amount of unsaponifiables and lower free fatty acids (FFA) content, as compared to the control treatment (No enzyme, 80°C, 2 h, p < 0.05). DH affected the fat yield and the unsaponifiables content of the fat, positively (p < 0.05). However, it did not affect the fat FFA content and iodine value (p > 0.05). Results obtained here showed DH can be used as an effective measure for controlling the physicochemical and functional properties of chicken skin protein hydrolysates and fat in the EAE process.     

Expected values of the number of failures for two populations under joint Type-II progressive censoring

The model in which joint Type-II progressive censoring is implemented on two samples from different populations in a combined manner is considered and the probabilities of failures are discussed. This model may have relevance for practical applications, when an experimenter need to know the expected values of the number of failures for each population. This knowledge plays an important role in the selection of appropriate sampling plans and the construction of efficient estimators for parameters. The formula allowing numerical computation of the expected value of the number of failures for each of the two populations is given. Also, a detailed numerical study of this expected value is carried out for different parametric families of distributions.     

Dynamic Correlation in Driven Vortex Phases

We describe transport experiments where the spatial gradient of the driving Lorentz force is controlled. The velocity profiles induced by the Lorentz force gradient in the driven liquid and lattice vortex phases are characteristic of hydrodynamic, plastic, and elastic motion.     

Power transistors fabricated using isotopically purified silicon (/sup 28/Si)

It is well known that isotopic purification of group IV elements can lead to substantial increases in thermal conductivity due to reduced scattering of the phonons. The magnitude of the increase in thermal conductivity depends on the level of isotopic purification, the chemical purity, as well as the test temperature. For isotopically pure silicon (/sup 28/Si) thermal conductivity improvements as high as sixfold at 20 K and 10%-60% at room temperature have been reported. Device heating during operation results in degradation of performance and reliability (electromigration, gate oxide wearout, thermal runaway). In this letter, we discuss the thermal performance of packaged RF LDMOS power transistors fabricated using /sup 28/Si. A novel technique allows the cost effective deployment of this material in integrated circuit manufacturing. A clear reduction of about 5/spl deg/C-7/spl deg/C in transistor average temperature and a corresponding 5%-10% decrease in overall packaged device thermal resistance is consistently measured by infrared microscopy in devices fabricated using /sup 28/Si over natural silicon.     

Obtaining full-diversity space-frequency codes from space-time codes via mapping

This paper considers the problem of space-frequency code design for frequency-selective multiple-input-multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) modulation. We show that space-time codes achieving full diversity in quasistatic flat fading environment can be used to construct space-frequency codes that can achieve the maximum diversity available in frequency-selective MIMO fading channels. Since the codes are constructed via a simple mapping from space-time codes to space-frequency codes, the abundant classes of existing space-time block and trellis codes can be used for full diversity transmission in MIMO-OFDM systems. The proposed mapping provides a tradeoff between the achieved diversity order and the symbol rate. Moreover, we characterize the performance of the space-frequency codes obtained via the mapping by finding lower and upper bounds on their coding advantages as functions of the coding advantages of the underlying space-time codes. This result will allow us to investigate the effects of the delay distribution and the power distribution of the channel impulse responses on the performance of the resulting space-frequency codes. Extensive simulation results are also presented to illustrate and support the theory.     

Role of angiotensin II and bradykinin on aortic collagen following converting enzyme inhibition in spontaneously hypertensive rats

We previously showed that chronic angiotensin-converting enzyme (ACE) inhibition prevented the increase in aortic collagen in spontaneously hypertensive rats (SHRs) independently of blood pressure reduction. The aim of the present study was to determine whether the effects of ACE inhibition on aortic fibrosis were due to inhibition of angiotensin II formation, preservation of bradykinin, or a combination of both. Four week-old SHRs were treated for 4 months with the ACE inhibitor quinapril, quinapril with the bradykinin B2 receptor antagonist Hoe 140, or the angiotensin II AT1 receptor antagonist CI996. Control SHR and Wistar-Kyoto (WKY) rats received a placebo for the same period of time. At the end of the treatment, as compared to conscious SHR and WKY controls, quinapril completely prevented the development of hypertension, whereas quinapril-Hoe 140 and the AT1 receptor antagonist produced only a partial reduction of blood pressure. In relation with blood pressure changes, aortic hypertrophy was significantly prevented by quinapril but not by quinapril-Hoe 140 or CI996. In contrast, aortic collagen accumulation was completely prevented by all three treatments. The study provides evidence that in young live SHRs, the prevention of aortic collagen accumulation is independent of blood pressure changes and bradykinin preservation and involves exclusively angiotensin II inhibition through AT1 receptors.     

Measurement of the vascular mass of the human radial artery by ultrasonics

OBJECTIVE: To determine the reproducibility of radial artery mass (RAM), in hypertensive patients. DESIGN AND METHODS: In 49 patients, RAM was measured using a high resolution echotracking device (Nius-02) which allows noninvasive measurement of diameter and wall thickness of the radial artery. RAM was validated in vitro by comparing weight of arterial segments to ultrasonographic measurement and determined as RAM = r (pi Re2-pi Ri2) where r is the arterial wall density (1.06 g/cm3), and Re and Ri are values of internal and external radii, respectively. Repeatability coefficient (RC2 = SDi2/n) was 1.3 mg. RESULTS: Blood pressure was (mean +/- SD) 146 +/- 19/85 +/- 15 mmHg, radial arterial diameter was 2,449 +/- 376 microns, radial wall thickness was 302 +/- 68 microns, RAM was 28 +/- 9 mg (range 13-43 mg). CONCLUSION: These results indicate that radial artery mass can be measured using a high resolution echotracking device.