Sökresultat

Filtyp

Din sökning på "*" gav 534164 sökträffar

Thermoresponsive properties of sugar sensitive copolymer of N-isopropylacrylamide and 3-(acrylamido)phenylboronic acid

The copolymer of N-isopropylacrylamide and 3-(acrylamido)phenylboronic acid (82:18, (M) over bar (n)=47000 g. mol(-1)) was prepared by free radical polymerization. The copolymer showed typical thermal precipitation behavior in aqueous solutions, its precipitation temperature (T-P) being increased from 23 to 32degreesC by increasing the pH from 6.5 to 9.7, because of ionization of the phenylboronat

Carotenoid to chlorophyll energy transfer in the peridinin-chlorophyll-a-protein complex involves an intramolecular charge transfer state

Carotenoids are, along with chlorophylls, crucial pigments involved in light-harvesting processes in photosynthetic organisms. Details of carotenoid to chlorophyll energy transfer mechanisms and their dependence on structural variability of carotenoids are as yet poorly understood. Here, we employ femtosecond transient absorption spectroscopy to reveal energy transfer pathways in the peridinin-chl

Blood velocity in the fetal vein of Galen and the outcome of high-risk pregnancy

BACKGROUND: Pulsation in the flow velocity waveform in the umbilical vein is related to perinatal mortality but the flow velocity waveform in the fetal vein of Galen is normally even and without fluctuation. OBJECTIVES: To establish whether blood flow velocity pulsations in the vein of Galen in high-risk pregnancies are related to outcome. STUDY DESIGN: The vein of Galen was located by colour Dopp

Short-term results of a randomized clinical trial comparing Lichtenstein open repair with totally extraperitoneal laparoscopic inguinal hernia repair

Background: Laparoscopic herniorrhaphy has emerged as a recognized operative method for inguinal hernia repair. This study compared the short-term results of two tension-free methods of repair: totally extraperitoneal (TEP) laparoscopic patch repair and the open Lichtenstein mesh technique. Methods: A total of 1513 men from 11 hospitals who presented with a primary unilateral inguinal hernia were

Citral a fragrance allergen and irritant

Citral is a well known contact allergen and a contact irritant. Routine patch testing in the past may have been restricted because of possible irritant (IR) patch test responses. 586 consecutive patients, with hand eczema, were patch tested with a selection of fragrances including citral 2% petrolatum and the European standard series. 28 of the patients showed a positive patch test reaction (+ to

Dispersed lipid liquid crystalline phases stabilized by a hydrophobically modified cellulose

Aqueous dispersions of monoolein (MO) with a commercial hydrophobically modified ethyl hydroxyethyl cellulose ether (HMEHEC) have been investigated with respect to the morphologies of the liquid crystalline nanoparticles. Only very low proportions of HMEHEC are accepted in the cubic and lamellar phases of the monoolein-water system. Due to the broad variation of composition and size of the commerc

Four-wave mixing with non-resonant pump and resonant probe for OH detection in flames

A new type of two-color four-wave mixing spectroscopy is theoretically and experimentally demonstrated. By employing a non-resonant pumping and resonant probing scheme, OH radicals are detected in a laminar, atmospheric pressure methane/air flame as a proof-of-principle experiment. Two 532 nm laser beams from a multi-mode Nd:YAG laser are utilized to create an electrostrictive grating in the flame

Linkage mapping of AFLP markers in a wild population of great reed warblers: importance of heterozygosity and number of genotyped individuals

Amplified fragment length polymorphisms (AFLP) are dominant markers frequently used to build linkage maps where heterozygosity could be inferred by a backcross breeding strategy. In the present study, we describe the utilization of an unmanipulated great reed warbler, Acrocephalus arundinaceus pedigree to infer heterozygous genotypes of AFLP markers in order to map these markers to a partial linka

Analysis of phase composition in aqueous two-phase systems using a two-column chromatographic method: Application to lactic acid production by extractive fermentation

A new chromatographic system for the simultaneous analysis of polyethylene glycol, dextran, sugars, and low-molecular-weight fatty acids was developed. The system is based on a gel exclusion column which allows a first separation between high- and low-molecular-weight compounds, and a cationic exchange column used to further separate the low-molecular-weight compounds. Two applications of the syst

Rhopalia are integrated parts of the central nervous system in box jellyfish

In cubomedusae, the central nervous system (CNS) is found both in the bell (the ring nerve) and in the four eye-bearing sensory structures (the rhopalia). The ring nerve and the rhopalia are connected via the rhopalial stalks and examination of the structure of the rhopalial stalks therefore becomes important when trying to comprehend visual processing. In the present study, the rhopalial stalk of

Soft-x-ray spectroscopic investigation of ferromagnetic Co-doped ZnO

The electronic properties of cobalt-doped ZnO were investigated through site-selective and element-sensitive x-ray-absorption spectroscopy in the vicinity of the Co L-2,L-3 edge, the oxygen K edge, and at the Zn L-3 edge. The spectroscopic measurements of the ferromagnetic cobalt-doped ZnO films appear to have additional components in the O K edge x-ray-absorption spectrum not observed in the undo

Cell harvesting by cross-flow microfiltration using a shear-enhanced module

Protein, produced by a bacterial culture of recombinant Vibrio cholerae, was separated from cells in a fermentation broth by cross-flow microfiltration. A new, mechanically agitated (rotational) shear filter, the DMF(TM) filter from Pall, was used to perform the separation. Higher protein recovery and permeate flux than commonly obtained during cell harvesting were demonstrated using sixfold conce

Consequences of maternal yolk testosterone for offspring development and survival: experimental test in a lizard.

1. Hormone-mediated maternal effects and developmental plasticity are important sources of phenotypic variation, with potential consequences for trait evolution. Yet our understanding of the importance of maternal hormones for offspring fitness in natural populations is very limited, particularly in non-avian species. 2. We experimentally elevated yolk testosterone by injection of a physiologica

pH dependence of the four individual transitions in the catalytic S-cycle during photosynthetic oxygen evolution.

We have investigated the pH dependence for each individual redox transition in the S-cycle of the oxygen evolving complex (OEC) of photosystem II by electron paramagnetic resonance (EPR) spectroscopy. In the experiments, OEC is advanced to the appropriate S-state at normal pH. Then, the pH is rapidly changed, and a new flash is given. The ability to advance to the next S-state in the cycle at diff

Isochromosome 17q in blast crisis of chronic myeloid leukemia and in other hematologic malignancies is the result of clustered breakpoints in 17p11 and is not associated with coding TP53 mutations

An isochromosome of the long arm of chromosome 17, i(17q), is the most frequent genetic abnormality observed during the disease progression of Philadelphia chromosome-positive chronic myeloid leukemia (CML), and has been described as the sole anomaly in various other hematologic malignancies. The i(17q) hence plays a presumably important pathogenetic role both in leukemia development and progressi

Microcirculation-derived factors in airway epithelial repair in vivo

Airway epithelial repair, by cell migration over a denuded, intact basement membrane, occurs rapidly in vivo. The present study examines microcirculation-derived factors in the reepithelialization process in the guinea pig. A well-defined tracheal zone was gently deepithelialized; no bleeding occurred and the basement membrane was left intact. Plasma exudation was visualized by use of iv colloidal

Metal toxicity affects fungal and bacterial activities in soil differently

Although the toxic effect of heavy metals on soil microorganism activity is well known, little is known about the effects on different organism groups. The influence of heavy metal addition on total, bacterial, and fungal activities was therefore studied for up to 60 days in a laboratory experiment using forest soil contaminated with different concentrations of Zn or Cu. The effects of the metals