Quick and easy molecular weight determination with Macintosh computers and public domain image analysis software

The program "molecular weights" allows a fast and easy estimation of molecular weights (M(r)), isoelectric point (pI) values and band intensities directly from scanned, polyacrylamide gels, two-dimensional protein patterns and DNA gel images. The image coordinates of M(r) and pI reference standards enable the program to calculate M(r) and pI values in a real time manner for any cursor position. The program requires NIH-Image for Macintosh computers and includes automatic band detection coupled with a densitometric evaluation.     

Alternative resist adhesion and electroplating layers for LIGA process

 The fabrication of high aspect ratio microstructures using the X-ray lithography and electroplating step of the LIGA process requires, that the metal layer on the substrate (plating base) enables a flawless resist adhesion and provides a high conductivity for the following electroplating process. In addition, a flawless metal adhesion after electroplating has to be ensured. Typically metal layers of titanium, but also of copper and gold are used. In case of higher structures, fluorescence radiation generated in the metal layer during exposure reduces the bond strength between the resist and the adhesion layer [7]. Since the fluorescence probability decreases with a decreasing atomic number, the suitability of conductive carbon as the plating base was investigated and compared to results achieved with titanium. The resist adhesion was increased tremendously on the carbon layer but the metal adhesion is insufficient. Therefore, platinum islands were deposited on the conductive carbon to facilitate good metal adhesion. The resulting resist adhesion was still superior compared to titanium. In addition, metal adhesion was achieved on these layers.     

Network Analysis of Commuting Flows: A Comparative Static Approach to German Data

The analysis of complex networks has recently received considerable attention. The work by Albert and Barabási presented a research challenge to network analysis, that is, growth of the network. The present paper offers a network analysis of the spatial commuting network in Germany. First, we study the spatial evolution of the commuting network over time. Secondly, we compare two spatial interaction model (SIM) specifications, in order to replicate the actual network structure. Our findings suggest that the commuting network appeared to become more dense and clustered, while the SIMs seem to require more sophisticated specifications, in order to replicate such a connectivity structure.     

The spatial distribution of new technology-based firms: Empirical results for West-Germany

The focus of the article is to shed some more light on the spatial distribution of new technology-based firms (NTBF) and to discuss location factors which may contribute to the explanation of the variation in the incidence of NTBF between the West-German districts (“Kreise”). Based on theoretical models explaining the location decisions of new firms, hypotheses are derived and tested in an empirical model. The regression results indicate strong correlations between the occurrence of NTBF and the proximity to Research and Development (R&D) facilities comprising universities, technical colleges and non-university institutes as well as private R&D. As expected, the impact of the various facilities varies with respect to their field of specialization, showing major positive correlations with respect to technical disciplines. Moreover, the estimates reveal out differences due to spatial characteristics such as infrastructure and other structural factors. Received: 26 April 1999 / Accepted: 28 November 1999     

Changes in the contents of mono-, di- and oligosaccharides in leek plants stored in cold room

The aim of this work is to present the results of the analysis of composition of mono-, di- and oligosaccharides, including the content of fructooligosaccharides as well as rafinose, stachyose in pseudo stalk of leek plants of the following cultivars: Shelton F1, Belton F1 and Parton F1. Leek plants were stored in cold room at the temperature 0 °C and relative humidity around 98% in the period from December to May. Fructose, glucose, saccharose, fructooligosaccharides (FOS) as well as α-galactosides were determined with the HPLC method with the application of water-alcohol extracts. It was shown that some of the studied parameters have changed during storage, i.e., the glucose content increased from 4.4 ± 0.3 to 16.2 ± 1.6, fructose from 4.7 ± 0.2 to 23.8 ± 0.4, saccharose from 5.1 ± 0.7 to 18.7 ± 0.1, depending on the cultivar and the storage period. The largest increase in the content of fructose and glucose took place between 60th and 90th day of storage which testifies to intensive hydrolysis of fructans. Leek cv. Parton F1 was characterised by the largest content of fructans and the lowest susceptibility to hydrolysis. The amount of kestose, nystose and rafinose after the period of storage changed from 0.3 ± 0.0 to 0.9 ± 0.2, 0.5 ± 0.1 to 1.8 ± 0.1, 0.8 ± 0.1 to 1.8 ± 0.2 g/100 g of dry mass, respectively. The content of stachyose, in turn, remained at a constant level and amounts to around 0.5 g/100 g of dry mass. Leek plants kept in typical refrigeration conditions are characterised by good durability and constitute a valuable merchandise. However, due to ongoing hydrolysis processes, the content of prebiotic substances decreased what lowered the health-promoting value.     

Transdermal nicotine use in postmenopausal women: does the treatment efficacy differ in women using and not using hormone replacement therapy?

This study of postmenopausal female smokers (N = 94) asked: During short-term smoking abstinence, do the beneficial effects of transdermal nicotine replacement therapy (NRT) on acute symptomatology (i.e., withdrawal, cigarette craving, smoking urges, mood, depressive symptoms, motor speed, and reaction time) differ in women who use and do not use hormone replacement therapy (HRT)? Participants were recruited according to HRT and non-HRT use (self-selecting), then randomized within strata to active nicotine or placebo nicotine patch. After 1 baseline week of smoking, participants quit smoking for 2 weeks. Women received cessation counseling and were monitored for abstinence. Dependent measures were collected during five clinic visits. Two-way analysis of covariance (ANCOVA) were run on change scores for dependent variables, with nicotine patch group (active/placebo) and HRT group (HRT/non-HRT) as independent variables and age as a covariate. No interactions were found between HRT and patch condition, but both showed specific effects. During the first abstinent week, women on active nicotine patch (compared with placebo) experienced less severe withdrawal, greater reductions in cigarette cravings, and lower (more favorable) Factor 1 scores on the Questionnaire of Smoking Urges. During the second abstinent week, women using HRT (compared with the non-HRT group) exhibited better mood (Profile of Mood States scores) and less depression (Beck Depression Inventory scores). These results suggest the following: First, the efficacy of transdermal nicotine replacement is not adversely modified by women's HRT use; second, ovarian hormones might influence women's responses to smoking cessation, and thus should be considered in developing effective strategies for women to quit smoking.     

Experimental evaluation of insulation material in roofing system under tropical climate

The objective of this study is to determine the influence of radiant barriers on conductive and radiative heat transfers when they are integrated to a building envelope and to compare their efficiency to traditional insulation material (mineral wools, polystyrene). It is also about determining which insulation material and process can lead to a better heat flux reduction through a building roof. For this study four identical small-scale test cells were used. Their respective roof was equipped with the insulation material to be tested: One with polystyrene, the second with a radiant barrier the third one with fibber glass and the last one with no insulation material was considered as the reference cell. Different test were performed with a view to evaluate the influence of parameters such as roof absorptivity and roof air layer ventilation on the heat flux reduction through the roof. With the measured temperature, the conductive and radiative heat fluxes were calculated. With a white corrugated iron roof top the heat flux reduction provided by the radiant barrier is 37%. With a black one this material allows a reduction of 33%. It is shown that whatever the roof absorptivity value, the radiative heat flux is predominant over the conductive one. With no ventilation, the radiant barrier is comparable to polystyrene and fiber glass; when the airspace is ventilated the radiant barrier provides a better insulation.     

Arteriovenous malformation of the base of tongue: case report and literature review

Arteriovenous malformations of the head and neck pose a challenging therapeutic and reconstructive problem. In this report we describe a rare case of an arteriovenous malformation of the base of tongue. The patient, a young adult female, was treated with embolization followed by surgical resection using a lateral pharyngotomy approach. Reconstruction of the extensive base of tongue defect was accomplished using a radial forearm free flap. Currently, the patient is decannulated, articulates clearly, tolerates a normal diet, and is without recurrence. Our treatment approach is discussed in detail and compared with alternative techniques.     

Inhibition of monoamineoxidase and day-night-rhythm: correlation of physiological and biochemical parameters (author's transl)

The motor activity of rats following medication with monoamine-oxidase inhibitors was registered continuously over a period of nine days. At the same time the enzyme activity of monoamineoxidase (MAO) form A and B and the concentration of serotonin, tryptophan, 5-hydroxyindolacetic acid and norepinephrine were measured in brain stem and hippocampi. We draw the following conclusions: 1. The rhythmic changes in the levels of serotonin and norepinephrine play a minor role in the circadian rhythm. 2. MAO-inhibitors influence the timing mechanism. A relationship between this finding and the therapeutic effect on depressed patients is discussed. 3 Dopaminergic neurons antagonize the activation by adrenergic neurons during the dark-period.