Temporal tracking of spectral variations

We propose a data adaptive spectral estimation algorithm which is suitable for nonstationary estimation situations. This algorithm is based on the conventional Fourier transform of the estimated autocorrelation function. The data adaptive feature is implemented into the autocorrelation function estimation. The algorithm is computationally efficient due to its recursive nature. Its frequency tracking performance is tested against another adaptive algorithm based on the frequently used least mean square algorithm (LMS) of Widrow and Hoff (1960). The two algorithms demonstrate similar performance in many situations. Computer simulations indicate that, when applied to a signal composed of two sinusoids with different power levels, the proposed algorithm tracks the lower-powered sinusoid better than the LMS algorithm.     

Modifications of proteoglycans secreted into the growth medium by young and senescent human skin fibroblasts

The properties of proteoglycans (PGs) secreted into the growth medium by normal young and senescent human skin fibroblasts (HFs) were investigated. In both cases, the incorporation per cell of radioactive precursors into total PGs was similar. The polysaccharide chains of PGs from young and senescent HFs were mainly represented by galactosaminoglycuronans and showed a similar range of size distribution. However, galactosaminoglycuronans of PGs secreted by senescent HFs had a lower content of unsulphated disaccharides and a lower proportion of D-glucuronosyl residues. Moreover, senescent HFs released into the growth medium higher relative amounts of small PGs with chondroitin sulphate, dermatan sulphate chains, such as decorin.     

Analysis of conjugated bile acids by high performance liquid chromatography and mass spectrometry

Because of the known advantages of coupling high performance liquid chromatography with mass spectrometry (HPLC-MS) in biological fluids, studies on the reversed-phase HPLC-MS system for direct analysis of conjugated bile acids in human bile samples are described. Ten samples of gallbladder bile of apparently healthy subjects were examined. The amounts of each tauro- and glycoconjugated bile acid as trifluoracetate were determined by mass fragmentography. Quantitation of at least 1 ng of each bile acid was possible.     

Efficient processing of XPath queries using indexes

A number of indexing techniques have been proposed in recent times for optimizing the queries on XML and other semi-structured data models. Most of the semi-structured models use tree-like structures and query languages (XPath, XQuery, etc.) which make use of regular path expressions to optimize the query processing. In this paper, we propose two algorithms called Entry-point algorithm (EPA) and Two-point Entry algorithms that exploit different types of indices to efficiently process XPath queries. We discuss and compare two approaches namely, Root-first and Bottom-first in implementing the EPA. We present the experimental results of the algorithms using XML benchmark queries and data and compare the results with that of traditional methods of query processing with and without the use of indexes, and ToXin indexing approach. Our algorithms show improved performance results than the traditional methods and Toxin indexing approach.     

Flavonol glycosides from whole cottonseed by-product

Cottonseeds are fed to high-producing dairy cows as a source of fat and highly-digestible fibre. Seven flavonol glycosides have been identified from whole cottonseed by-product. Their structures were established as quercetin 3-O-{β-d-apiofuranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside} (1), kaempferol 3-O-{β-d-apiofuranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside} (2), quercetin 3-O-[β-d-apiofuranosyl-(1 → 2)-β-d-glucopyranoside] (3), quercetin 3-O-β-d-glucopyranoside (4), kaempferol 3-O-[α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside] (5), quercetin 3-O-[α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside] (6), and kaempferol 3-O-α-l-rhamnopyranoside (7). Gallic acid (8) and 3,4-dihydroxybenzoic acid (9) were also found. All structures were elucidated by ESI-MS and NMR spectroscopic methods. Total polyphenols were assayed by the Folin–Ciocalteu method.     

Chondroitin 4-sulphate exhibits inhibitory effect during Cu2+-mediated LDL oxidation

OBJECTIVE: To determine whether the rate of cardiovascular disease is different among parous women with a general practitioner reported history of toxaemia of pregnancy than among those not reported to have experienced toxaemia, or among nulliparous women. DESIGN: Prospective cohort study. SETTING: 1400 general practitioners throughout the United Kingdom. SUBJECTS: Women who had never used oral contraceptives who were recruited to the Royal College of General Practitioners' oral contraception study (original cohort about 23000). MAIN OUTCOME MEASURES: Age, social class, and smoking standardised incidence rates for hypertensive disease, acute myocardial infarction, other acute ischaemic heart disease, other chronic ischaemic heart disease, angina pectoris, total ischaemic heart disease, total cerebrovascular disease, and total venous thromboembolic disease in the three groups. RESULTS: Compared with parous women with no history of toxaemia, those who had experienced toxaemia had a significantly increased risk of hypertensive disease (relative risk (RR) 2.35), acute myocardial infarction (RR 2.24), chronic ischaemic heart disease (RR 1.74), angina pectoris (RR 1.53), all ischaemic heart disease (RR 1.65), and venous thromboembolism (RR 1.62). The rates for all cerebrovascular disease and peripheral vascular disease were also increased but not significantly. Nulliparous women were more likely to develop hypertension or all cerebrovascular disease later in life than parous women without a history of toxaemia. CONCLUSIONS: A history of toxaemia of pregnancy increases the risk of several distinct cardiovascular conditions later in life. Although causality cannot be inferred (other characteristics of the women may account for both an increased risk of toxaemia and a risk of subsequent vascular disease), the findings merit further research because of their potential importance.     

PIXE micro-beam mapping of metals in human peri-implant tissues

Previous investigations did not agree about the possible presence of titanium and other metals in the tissues around endosteal dental implants and joint prostheses. Indeed, while some authors reported diffusion of metals into the tissues, some others did not find evidence of this phenomenon. In the present study, four dental titanium implants, removed with the surrounding tissues from patients at various time intervals after the insertion, were studied by means of the micro-beam proton-induced X-ray emission (PIXE -beam) technique, which draws maps showing the tissue distribution of elements with a detection limit of about 1 ppm. One implant was built in commercially pure titanium, two others in titanium coated with titanium plasma spray, and the fourth in Ti–Al–V alloy. Their composition was confirmed by the PIXE -beam analyses. The removed samples were embedded in epoxy and processed with a cutting–grinding appliance, mounted on plastic holders, and ground up to a thickness of about 35 m. Optical microscope examinations were also carried out, to compare the optical findings with the elemental maps obtained with the PIXE -beam. One implant, removed after 70 days because the patient had developed peri-implantitis, had some inflammatory soft tissue attached, with no evidence of metal leakage. The other three implants had been removed after 6, 7 and 9 years of valid clinical service, because of the fracture of the prosthetic abutment or the implant stem. At the optical microscope, all these fixtures were embedded in mature bone. The elemental maps indicated small titanium deposits in about 5% of the bone bordering the implants, while aluminum, when present in the fixture, leaked diffusely into the surrounding bone and vanadium was not found in the tissues. These results suggest that titanium may be found occasionally in peri-implantar tissues, but has very little tendency to spread, while the presence of aluminum in the implant alloy may cause an important leakage of this metal.     

A single layer hydrogen silsesquioxane (HSQ) based lift-off process for germanium and platinum

Primarily used as etch mask, single layer hydrogen silsesquioxane has never been investigated for lift-off technique. In this article, we propose a new technique where a single layer of hydrogen silsesquioxane, a negative tone electron beam resist, is used to make lift-off of germanium and platinum. Removal of exposed hydrogen silsesquioxane is tested for various concentrations of hydrofluoric acid. Ultrasonic agitation is also used to reduce the formation of flakes due to accumulation of matter (evaporated metal in our case) along the sidewalls of the lift-off narrow slots. Results demonstrate potential in applying the hydrogen silsesquioxane as a negative tone lift-off resist to pattern nanometer scale features into germanium and platinum layers.     

Analysis of polyunsaturated fatty acids in newborn sera: a screening tool for atopic disease?

It has been demonstrated that patients with atopic disease have anomalies of fatty acid composition, as a result of altered metabolism or abnormal incorporation of fatty acids into the tissues. In the present study, in 57 newborns 'at risk' for atopic disease, the polyunsaturated fatty acid (PUFA) levels were found to be lower in cord blood in infants who subsequently developed atopic disease than in non-atopics. In all babies, levels of arachidonic acid and dihomo-gamma-linolenic acid in sera at 1 and 3 months of age were lower than those in cord blood. These changes were more marked in children who subsequently developed atopic disease, and in those who, independently of signs and/or symptoms of atopic disease, were formula-fed. A comparison between IgE and PUFA levels revealed no significant differences at any tested time interval. In conclusion, our data suggest that in children 'at risk' for atopy, PUFA levels may be predictive of atopic disease.