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Incomplete lipid chain freezing of sonicated vesicular dispersions of double-tailed ionic surfactants

Lipid freezing in dilute sonicated vesicular dispersions was studied using differential scanning calorimetry (DSC) and H-1 NMR. For charged, anionic, or cationic lipids, approximately half of the lipids remain in a fluid state when cooled 20 degrees C below the main chain melting temperature. With a zwitterionic phospholipid, on the other hand, essentially no supercooling of the liquid state was o

Optimization and application of homogeneous liquid-liquid extraction in preconcentration of copper (II) in a ternary solvent system

In this study a homogeneous liquid-liquid extraction based on the Ph-dependent phase-separation process was investigated using a ternary solvent system (water-acetic acid-chloroform) for the preconcentration of Cu2+ ions. 8-Hydroxy quinoline was used as the chelating agent prior to its extraction. Flame atomic absorption spectro photometry using acetylene-air flame was used for the quantitation of

Semiclassical Theory of Bardeen-Cooper-Schrieffer Pairing-Gap Fluctuations

uperfluidity and superconductivity are genuine many-body manifestations of quantum coherence. For finite-size systems the associated pairing gap fluctuates as a function of size or shape. We provide a theoretical description of the zero temperature pairing fluctuations in the weak-coupling BCS limit of mesoscopic systems characterized by order or chaos dynamics. The theory accurately describes exp

The VpreB1 enhancer drives developmental stage-specific gene expression in vivo

In adult mice, the VpreB genes are expressed in bone marrow progenitor (pro-) and precursor (pre-) B cells. As part of the pre-B cell receptor, the proteins are crucial for the proliferation of these cells and consequently normal B lymphocyte development. Using cell lines, we identified a lineage- and developmental-stage-specific VpreB1 enhancer. Here, we analyze its specificity in vivo by generat

Gas transfer rate and CO2 flux between an unproductive lake and the atmosphere in northern Sweden

Measurements of the gas transfer rate of CO2 between lake water and the atmosphere present a critical problem for the understanding of lake ecosystem carbon balances and landscape carbon budgets. We present calculations of the gas transfer rate of CO2 from direct measurements of the CO2 flux using an eddy covariance system and concurrent measurements of the concentration of CO2 in the surface wate

The influence of production systems on self-reported arousal, sleepiness, physical exertion and fatigue-consequences of increasing mechanization

The present study examined the capability of a real-time assessment routine to sort out the individual impact of three production systems on psychological activation as measured by the Stress/Energy Inventory, Karolinska Sleepiness Scale, Borg's CR-10 Perceived Exertion scale, and the Swedish Occupational Fatigue Inventory. Sixteen women between the ages of 26 and S7 years (mean 43 years) rotated

Segmentation of medical images using three-dimensional active shape models

In this paper a fully automated segmentation system for the femur in the knee in Magnetic Resonance Images and the brain in Single Photon Emission Computed Tomography images is presented. To do this several data sets were first segmented manually. The resulting structures were represented by unorganised point clouds. With level set methods surfaces were fitted to these point clouds. The iterated c

Abdominal injury from sporting activities

The frequency of abdominal injury is rising. In an analysis of 1,354 cases of closed abdominal trauma sustained during a 30-year period (1950-1979) in Skaraborg County, Sweden, a distinct increase was found in the numbers associated with sporting activities. The severity of the injuries caused by sports likewise showed an increase. The representation of injured organs was of the same order as in t

Recommendations for the standardization and interpretation of the electrocardiogram. Part I: The electrocardiogram and its technology. A scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society

This statement examines the relation of the resting ECG to its technology. Its purpose is to foster understanding of how the modern ECG is derived and displayed and to establish standards that will improve the accuracy and usefulness of the ECG in practice. Derivation of representative waveforms and measurements based on global intervals are described. Special emphasis is placed on digital signal

Temperature constraints on the growth and functioning of root organ cultures with arbuscular mycorrhizal fungi

(.) In this study we investigated the effects of temperature on fungal growth and tested whether the differences in fungal growth were related to the effects of temperature on carbon movement to, or within, the fungus. (.) Growth curves and C uptake-transfer-translocation measurements were obtained for three arbuscular mycorrhizal fungi (AMF) isolates cultured within a 6-30 degrees C temperature r

Increased cystatin C expression in the pre-eclamptic placenta.

Trophoblast invasion is regulated by proteinases and their inhibitors. Cystatin C inhibits cysteine proteinases. The serum concentration of cystatin C is increased in late pregnancy and pre-eclampsia. We aimed to investigate whether the expression of cystatin C is increased in the pre-eclamptic placenta and to investigate the expression pattern of cystatin C mRNA and protein in placental tissue. T

CART-peptide immunoreactivity in enteric nerves in patients with Hirschsprung's disease

Aims: Cocaine- and amphetamine-regulated transcript (CART)-peptide is found in the brain and participates in the control of feeding behavior. It is also expressed in the peripheral nervous system and is suggested to have neuromodulatory and/or neurotrophic effects in rat intestine. The aims of this study were to investigate the presence of CART-peptide in the normal ganglionic as well as aganglion

Surface-plasmon-enhanced optical forces in silver nanoaggregates

We use extended Mie theory to investigate optical forces induced by and acting on small silver nanoparticle aggregates excited at surface plasmon resonance. It is shown that single molecules can be trapped at junctions between closely spaced nanoparticles, which are simultaneously pulled together by optical forces. These effects could significantly influence surface-enhanced Raman scattering and r

Multifocal optical systems and pupil dynamics in birds.

In animal eyes of the camera type longitudinal chromatic aberration causes defocus that is particularly severe in species with short depth of focus. In a variety of vertebrates, multifocal optical systems compensate for longitudinal chromatic aberration by concentric zones of different refractive powers. Since a constricting circular pupil blocks peripheral zones, eyes with multifocal optical syst

Topographic representation of the pharyngoesophageal segment during swallowing

Motility of the pharyngoesophageal segment (PES) was monitored by cineradiography (50 frames a second) during barium swallow and analyzed by a computerized topographic mapping of sagittal wall motion. Through measurement of wall displacement on 20 consecutive levels of the PES, distention, contraction, and peristalsis were studied. Topographic mapping of three patients with normal PES motility, de

The gender differences in growth hormone-binding protein and leptin persist in 80-year-old men and women and is not caused by sex hormones.

objective Leptin and growth hormone-binding protein (GHBP) both show gender differences that might be explained by sex hormones. To study the potential relevance of oestradiol and testosterone, we have examined 80-year-old subjects in whom oestradiol is higher in men than in women. The interrelationships between leptin, insulin, GHBP and fat mass in this age group were also investigated. design a