Radio frequency glow discharge source with integrated voltage and current probes used for sputtering rate and emission yield measurements at insulating samples

Radio frequency glow discharge optical emission spectroscopy (RF-GD-OES) is routinely used for the chemical analysis of solid samples. Two independent electrical signals from the discharge are required for quantification. When sputtering insulating samples, the voltage over the discharge is not directly measurable. The coupling capacity of the sample is required in order to calculate the discharge voltage. A procedure is outlined where the coupling capacity is determined using an electrical measurement without discharge. The calculated time-dependent discharge voltage and current are evaluated using a plasma equivalent circuit. An insulating sample is sputtered at constant cathode voltage and current. The emission yield for an aluminium line is comparable to that of conducting reference material.

Glow discharge mass spectrometry

Over the past twenty years or so, glow discharge mass spectrometry (GDMS) has become the industry standard for the analysis of trace elements in metals and semiconductors. A review of its history is followed by a picture of the present situation and a look to where the future may lie. Applications are summarised, including the ability of GDMS to offer depth-resolved data and non-conductor analysis, and the well-documented quantitative nature of the results is reviewed. The effects resulting from the physical properties of the analyte material are discussed at length. Finally, recent work such as "fast flow" sources and pulsed glow discharges is reviewed.

Early changes in experimental osteoarthritis using the Pond-Nuki dog model: technical procedure and initial results of in vivo MR imaging

The purpose of this study was to prove the feasibility of combining in vivo MR imaging with the Pond-Nuki animal model for the evaluation of osteoarthritis. In an experimental study, 24 beagle dogs underwent transection of the anterior cruciate ligament of the left leg (modified Pond-Nuki model). The dogs were randomly assigned into four groups and examined by MRI after 6, 12, 24 and 48 weeks. MR imaging of both knees was performed under general anesthesia with the contralateral joint serving as control. In group 1 (6 weeks postoperatively), the first sign detected on MRI was subchondral bone marrow edema in the posteromedial tibia. After 12 weeks, erosion of the posteromedial tibial cartilage could be observed, followed by meniscus degeneration and osteophytosis after 24 and 48 weeks. The contralateral knee joint showed transient joint effusion, but no significant signs of internal derangement (P<0.001). By combining in vivo MR imaging with the Pond-Nuki model, it is possible to detect early signs of osteoarthritis. The first sign was posteromedial subchondral bone marrow edema in the tibia followed by progressive cartilage degeneration and joint derangement. The in vivo model therefore seems to be suitable for longitudinal studies or monitoring the therapeutic effects of osteoarthritis.

Small interacting peptides. Part II: Interaction of cyclohexapeptides with immobilised model peptides. Comparison of infrared investigations, principal components analysis and force field calculations

The interaction of cyclic peptides with surface-bound model peptides was investigated by ATR-FTIR spectroscopy, principal components analysis and force field calculations. Information about the interacting functional COOH, COO-, and NH3+ groups and the peptide backbone was gained through a set of cyclohexapeptides (seven of the type c(X1KX2KX3K) (K = L-lysine) and one of the type c(X1KX2KX3k) (k = D-lysine), which are interacting with L-arginine- or tripeptide-coated Si-ATR crystals. All measurements were performed in aqueous solutions. Spectra evaluation in the range 1800-1500 cm(-1) was done by band and principal components analysis (PCA). Only adsorbed molecules were present in these spectra. The coatings were investigated by ATR-FTIR spectroscopy too in order to characterise their functional groups. Based on this knowledge, the spectra of the interacting partners could be evaluated in relation to cyclohexapeptides and coatings. As a result, it was possible to identify the distinct differences in the bonding behaviour of the various peptides.

Comparison of the annealing behavior of thin Ta films deposited onto Si and SiO2 substrates

Structural changes at annealing temperatures (T(an)) of 500-1,100 degrees C were investigated for thin Ta films which were sputter-deposited onto pure Si substrates and onto thermally oxidized Si. In the as-deposited state, the Ta layers predominantly consist of metastable tetragonal beta-Ta, whereby the [001] texture is independent of the substrate material. At lower annealing temperatures, the microstructural evolution is essentially the same for both Ta films. Incorporation of O atoms causes an increase of the intrinsic compressive stress, and diffusion of C atoms into the Ta layer leads to the formation of Ta(2)C. Additionally, a partial transformation of the original beta-Ta phase into a second phase with tetragonal unit cell (denoted as beta'-Ta) occurs. For the Ta/Si system, the formation of a Ta-Si intermixing layer is initiated at T(an)=550 degrees C, and nucleation of crystalline TaSi(2) occurs at T(an)=620 degrees C. The formation of a second Ta silicide was not detected up to T(an)=900 degrees C. In the case of the Ta film deposited onto the SiO(2) substrate, the metastable beta-Ta and the beta'-Ta transform completely into the thermodynamically stable cubic alpha-Ta at T(an)=750 degrees C. A marked reaction with the substrate indicated by the formation of Ta(2)O(5) and Ta(5)Si(3) occurs at T(an)=1,000 degrees C.

Is the Second Phase of the Formalin Test Useful to Predict Activity in Chronic Constriction Injury Models? A Pharmacological Comparison in Different Species

This study presents data of several reference drugs in rats and gerbils for both the second phase of the formalin test and the cold allodynia in animals with a constriction injury of the sciatic nerve. A pharmacological validation of the formalin test and the CCI model in gerbils was performed. It was evaluated whether the second phase of the formalin test could be used as a pharmacological screening to predict outcome in the cold plate test in CCI animals. Male Sprague Dawley and Wistar rats and male gerbils were used for both tests. For the formalin test, animals were injected in the right hind paw (5% formalin rat: 0.05 microl; gerbil: 0.01 microl) and flinching and licking or biting were recorded. For CCI testing, a Bennett operation was performed on the left hind paw 7 days before testing. Cold plate allodynia was evaluated before and after drug treatment. In rats, a good correlation between both test conditions for morphine, fentanyl, MK-801 and flunarizine was found. Clonidine tends to have more activity in the second phase of the formalin test, whereas baclofen, tramadol, amitryptiline, ketamine and topiramate demonstrate to be more active in the cold plate. In gerbils, a good correlation between both test conditions for fentanyl and ketoprofen was found. Tramadol and CP-96345 tend to have more activity in the second phase of the formalin test, whereas morphine, SR-48968, SR-142801 and R116301 demonstrates to be more active in the cold plate test. In the present acute test conditions, there is a correlation in the pharmacological activity in rats and gerbils for the tested compounds a correlation between the second phase of the formalin test and the cold allodynia in CCI animals is found. Comparing to human data the screening drugs tested in this study show a correlation between animal and human studies in these specific circumstances. Further validation studies are needed to make these correlations clinical applicable.

Internal and External Factors Affecting the Development of Neuropathic Pain in Rodents. Is It All About Pain?

It is important to know the factors that will influence animal models of neuropathic pain. A good reproducibility and predictability in different strains of animals for a given test increases the clinical relevance and possible targeting. An obligatory requirement for enabling comparisons of results of different origin is a meticulous definition of the specific sensitivities of a model for neuropathic pain and a description of the test conditions. Factors influencing neuropathic pain behavior can be subdivided in external and internal factors. The most important external factors are; timing of the measurement of pain after induction of neuropathy, circadian rhythms, seasonal influences, air humidity, influence of order of testing, diet, social variables, housing and manipulation, cage density, sexual activity, external stress factors, and influences of the experimenter. The internal factors are related to the type of animal, its genetic background, gender, age, and the presence of homeostatic adaptation mechanisms to specific situations or stress. In practice, the behavioral presentations to pain depend on the combination of genetic and environmental factors such as accepted social behavior. It also depends on the use of genetic manipulation of the animals such as in transgenic animals. These make the interpretation of data even more difficult. Differences of pain behavior between in- and outbred animals will be better understood by using modern analysis techniques. Substrains of animals with a high likelihood for developing neuropathic pain make the unraveling of specific pathophysiological mechanisms possible. Concerning the effect of stress on pain, it is important to differentiate between external and internal stress such as social coping behavior. The individual dealing with this stress is species sensitive, and depends on the genotype and the social learning. In the future, histo-immunological and genetic analysis will highlight similarities of the different pathophysiological mechanisms of pain between different species and human subjects. The final objective for the study of pain is to describe the genetics of the eliciting pain mechanisms in humans and to look for correlations with the knowledge from basic research. Therefore, it is necessary to know the genetic evolution of the different mechanisms in chronic pain. In order to be able to control the clinical predictability of a putative treatment the evolutionary pharmacogenomic structure of specific transmitters and receptors must be clarified.

Induction of Apoptosis of CD4+ T Cells by Immunomodulatory Therapy of Multiple Sclerosis with Glatiramer Acetate

Glatiramer acetate (GA), a mixture of synthetic polypeptides, has beneficial effects on the clinical course and the MRI-defined disease activity of patients with multiple sclerosis (MS). In MS, evidence has been provided that the apoptosis of disease-relevant T cells is dysregulated. In this study, we investigated the effect of GA on T cell apoptosis, T cell activation, and cytokine profile of lymphocytes derived from 19 relapsing-remitting MS patients during the first year of GA therapy. Analysis of blood samples obtained every 6 weeks showed an increase in apoptotic T helper cells after 30 weeks of therapy. This effect remained until the end of the study and was accompanied by an increase in activated T cells and interleukin-4-producing lymphocytes. Thus, in addition to the established effect of GA on the cytokine network, GA-mediated immunomodulation might involve the apoptotic elimination of T helper cells.

Efficacy and safety of repeated intrathecal triamcinolone acetonide application in progressive multiple sclerosis patients

Available immunomodulatory and conventional steroid treatment options for patients with progressive multiple sclerosis (MS) only provide limited symptomatic benefit. We performed an open trial on the short-term and long-term efficacy and safety of repeated intrathecal application of the sustained release steroid triamcinolone acetonide (TCA) in 36 progressive MS patients. Six TCA administrations, performed every third day, reduced the EDSS score (initial: 5.6+/-0.93 [mean+/-S.D.]; end: 4.9+/-1.0; p<0.001) and increased the walking distance (WD) (initial: 294+/-314 m; end: 604+/-540 m; p<0.001). Twenty MS patients continued intrathecal TCA treatment with one TCA injection performed with a variable frequency ranging from 6 to 12 weeks. Both EDSS and walking distance remained stable in these patients until the end of the follow-up investigation period. No serious side effects occurred. We conclude that repeated intrathecal TCA injection provides substantial benefit for progressive MS patients with predominantly spinal symptoms.

Improvement of image quality of non-invasive coronary artery imaging with magnetic resonance by the use of the intravascular contrast agent Clariscan (NC100150 injection) in patients with coronary artery disease

PURPOSE

To assess the feasibility of Clariscan, an intravascular contrast agent, for free breathing, navigator assisted, high resolution, three-dimensional-magnetic resonance coronary angiography (MRCA) in patients, as extracellular contrast agents are unfavorable for the improvement of image quality.

MATERIALS AND METHODS

MRCA was performed in 10 patients with known coronary artery disease (CAD) with (1-5 mg Fe/kg body weight) and without contrast agent.

RESULTS

Compared to unenhanced images, Clariscan did not improve signal-to-noise (SNR) or contrast-to-noise ratios (CNR) compared to fat or myocardium in the proximal parts of the coronary arteries. However, when analyzing the peripheral parts (>4 cm from origin), CNR(fat) and CNR(myo) improved up to a factor of 1.81 and 5.85, respectively, at a dose of 3 mg Fe/kg body weight, while SNR did not reach statistical significance. The visible length of the coronary arteries was improved from 49 +/- 18 mm to 73 +/- 33 mm. The proximal diameter was reduced from 3.6 +/- 0.8mm to 3.2 +/- 0.8 mm, representing more closely the diameter of 3.1 +/- 0.7 mm measured by quantitative coronary angiography. Of 11 significant stenoses (>50%), eight were identified in the enhanced compared to six in the unenhanced images.

CONCLUSION

The use of Clariscan at a dose of 2-3 mg Fe/kg body weight improves image quality of three-dimensional-MRCA, especially in the peripheral segments, and, thus, the diagnostic accuracy for the detection of CAD.

Crystal structure of Thermotoga maritima alpha-glucosidase AglA defines a new clan of NAD+-dependent glycosidases

Glycoside hydrolase family 4 represents an unusual group of glucosidases with a requirement for NAD+, divalent metal cations, and reducing conditions. The family is also unique in its inclusion of both alpha- and beta-specific enzymes. The alpha-glucosidase A, AglA, from Thermotoga maritima is a typical glycoside hydrolase family 4 enzyme, requiring NAD+ and Mn2+ as well as strongly reducing conditions for activity. Here we present the crystal structure of the protein complexed with NAD+ and maltose, refined at a resolution of 1.9 A. The NAD+ is bound to a typical Rossman fold NAD+-binding site, and the nicotinamide moiety is localized close to the maltose substrate. Within the active site the conserved Cys-174 and surrounding histidines are positioned to play a role in the hydrolysis reaction. The electron density maps indicate that Cys-174 is oxidized to a sulfinic acid. Most likely, the strongly reducing conditions are necessary to reduce the oxidized cysteine side chain. Notably, the canonical set of catalytic acidic residues common to other glucosidases is not present in the active site. This, combined with a high structural homology to NAD-dependent dehydrogenases, suggests an unusual and possibly unique mechanism of action for a glycoside-hydrolyzing enzyme.

Small interacting peptides. Part I. Interaction of cyclohexapeptides with an unspecific SiOH surface: comparison of infrared investigations and force field calculations

The interaction of cyclohexapeptides c(X(1)(1)K(2)X(2)(3)K(4)X(3)(5)K(6)) in water with hydrolysed silicon surfaces were studied by attenuated total reflection Fourier transform infrared (ATR FTIR) spectroscopy and by force field calculations. The band sequences (1800-1500 cm(-1)) for dissolved and adsorbed cyclohexapeptides were recorded and compared with those obtained after flushing with distilled water in order to eliminate the background signal of the peptides in solution. Band analyses and principal component analyses were carried out for the characteristic peptide vibrations in order to evaluate the spectra. In addition, force field calculations were performed to study the binding energies to the surface and to illustrate the possible structures of the cyclohexapeptides. The positively charged lysine side chains of the cyclohexapeptides interact with the OH groups of the surface, as indicated by band shifts. This also was verified by the force field calculations. The bonding stability increases with the number of interacting sites (lysine side chains and other peptide residues) to the surface. These sites are determined by structure and polarity of the cyclohexapeptides.

Three-dimensional magnetic resonance coronary angiography using a new blood pool contrast agent: initial experience

OBJECTIVE

The aim of this feasibility study was to assess the effect of a new blood pool contrast agent on magnetic resonance coronary angiography (MRCA) in patients suspected of having coronary artery disease.

METHODS

Nine patients referred for diagnostic x-ray coronary angiography in the evaluation of chest pain underwent MRCA using a thin-slab three-dimensional (3D) breath-hold segmented gradient echo technique at 1.5 T before and after intravenous administration of feruglose, a new blood pool contrast agent.

RESULTS

A total of 36 coronary arteries, including 15 stenoses were evaluated. Overall agreement of visually assessed stenoses > 50% was 86%. The mean signal-to-noise ratio in the left anterior descending artery (LAD) did not change significantly after contrast administration, a relative improvement of 1.2 +/- 0.4 (p = 0.1), whereas the mean contrast-to-noise ratio of blood to myocardium improved by 3 +/- 2 (p = 0.01).

CONCLUSION

A thin-slab 3D breath-hold scan combined with feruglose allows rapid localization and coverage of the proximal coronary arteries.

Initial experience with the intravascular contrast agent NC100150-injection (Clariscan) for breath-hold and navigator-gated magnetic resonance coronary artery imaging

PURPOSE

To examine magnetic resonance coronary artery imaging after NC100150-Injection.

MATERIALS AND METHODS

Breath-hold and navigator-gated images were acquired in five patients.

RESULTS

Breath-hold image quality, coronary artery-fat SDNR, and coronary artery SNR improved. Respiratory artifacts due to reduced liver signal intensity degraded navigator-gated image quality.

CONCLUSION

NC100150-Injection improves breath-hold coronary artery imaging. Navigator-gated acquisitions should use techniques that are insensitive to T2* effects.

Piroxicam versus tenoxicam in spine surgery: a placebo controlled study

In double-blind trial 60 patients undergoing spine surgery were randomized to receive either placebo, tenoxicam 40 mg intravenously (i.v.), tenoxicam 40 mg intramuscularly (i.m.) or piroxicam 40 mg i.m., immediately following the induction of general anesthesia. As compared to placebo, the 24 hour morphine consumption was reduced in all groups. This reduction was only statistically significant (p = 0.023) in the i.v. group (21.7 +/- 11.27 versus 36.53 +/- 20.33 mg). Rest and dynamic pain scores were significantly lower in both tenoxicam groups but more consistently in the i.v. group. With piroxicam only rest pain scores at 24 hours were lower. Less urinary retention was noticed in the i.v. tenoxicam group. This study shows that, following spine surgery, i.v. tenoxicam induces a morphine sparing effect (41%) while offering lower rest and dynamic pain scores and a lower incidence of urinary retention.

Transmission of 3 keV Ne7+ ions through nanocapillaries etched in polymer foils: evidence for capillary guiding

We report unprecedented transmission experiments of 3 keV Ne7+ ions through capillaries of 100 nm diameter and 10 microm length produced by etching ion tracks in a polymer foil. We studied foils tilted up to +/-20 degrees for which the incident ions are forced to interact with the capillary surface. Surprisingly, the majority of Ne7+ ions were found to survive the surface scattering events in their initial charge state. The angular distributions of the transmitted particles indicate propagation of the Ne7+ ions along the capillary axis. This capillary guiding of the Ne7+ ion provides evidence that the inner walls of the capillaries become charged and electron capture from the surface is suppressed in a self-organizing process.

A null mutation within the ciliary neurotrophic factor (CNTF)-gene: implications for susceptibility and disease severity in patients with multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. Impaired remyelination and axonal degeneration may account for progressive disability in MS patients. As ciliary neurotrophic factor (CNTF) takes part in myelogenesis, we examined the frequency of a CNTF-null mutation in 349 MS patients with respect to their clinical presentation and in comparison with 434 healthy controls. Similar genotype frequencies for the CNTF mutation were obtained in MS patients (genotype 0101=74.8%, 0102=22.3%, 0202=2.9%) and controls (genotype 0101=71.7%, 0102=26.5%, 0202=1.8%) even after stratification for the HLA-DRB1*15 allele. In addition, there was no significant correlation of CNTF genotypes to age at onset, course or severity of the disease. We therefore conclude, that the requirement for CNTF in myelogenesis or cell survival may be bypassed by a second ligand or redundancy of functional activity of other neurotrophic factors.

Multiple sclerosis: modulation of apoptosis susceptibility by glatiramer acetate

OBJECTIVES

We investigated whether therapy of multiple sclerosis (MS) with glatiramer acetate (GA) involves the modulation of programmed cell death (apoptosis) in disease-relevant T-helper lymphocytes.

MATERIAL AND METHODS

Blood was drawn from 15 relapsing-remitting MS patients both before (baseline) as well as 6, 12, and 18 weeks after GA therapy and from 15 healthy controls. Detection of apoptosis was performed in response to in vitro stimulation with GA, myelin basic protein or medium alone.

RESULTS

T-helper lymphocytes from untreated MS patients displayed an overall increased apoptosis susceptibility in vitro, compared to controls. During subsequent GA therapy, apoptosis vulnerability of these T cells in MS patients significantly declined under the initial baseline before treatment, and was finally equal in treated patients and controls. GA itself had no direct apoptosis-modulatory properties in vitro.

CONCLUSION

Our findings indicate that therapy of multiple sclerosis with glatiramer acetate presumably involves the compensation of altered apoptosis in T-helper lymphocytes.

Kinetically assisted potential sputtering of insulators by highly charged ions

A new form of potential sputtering has been found for impact of slow ( < or = 1500 eV) multiply charged Xe ions (charge states up to q = 25) on MgO(x). In contrast to alkali-halide or SiO2 surfaces this mechanism requires the simultaneous presence of electronic excitation of the target material and of a kinetically formed collision cascade within the target in order to initiate the sputtering process. This kinetically assisted potential sputtering mechanism has been identified to be present for other insulating surfaces as well.

Breath-hold 3D MR coronary angiography with a new intravascular contrast agent (feruglose)—first clinical experiences

Demonstration of the initial results of breath-hold 3D MR coronary angiography with patients using a new intravascular contrast agent (feruglose). Contrast-enhanced 3D MR-coronary angiography was performed in 5 patients with coronary artery disease after administration of feruglose in three different doses (0.5 (n = 3), 2, 5 mg Fe/kg body weight for each patient). MR coronary angiography was performed with an ECG-triggered 3D-FLASH-sequence during breath-hold at 1.5 T (TR 6.8 ms, TE 2.5 ms, flip-angle 30 degrees ). To reduce data acquisition time, only the two anterior elements of the phased-array body coil were activated. The data acquisition window within the cardiac cycle ranged between 217-326 ms depending on the matrix. Signal-to-noise (SNR) and contrast-to-noise ratios (CNR) of the coronary arteries were analyzed, and the results for the detection of coronary artery stenoses were compared with those obtained by conventional coronary angiography. SNR and CNR revealed an improved image quality at a dose of 2 mg Fe/kg compared with the lower dose, but no further improvement was obtained by rising the dose to 5 mg Fe/kg. Except for the left circumflex artery of one patient, at minimum the proximal parts of all four main coronary arteries could be imaged for all patients. Within the visible parts of the coronary arteries, six of eight significant coronary stenoses were identified correctly. Imaging of the proximal parts of the coronary arteries including detection of stenoses is possible during breath-hold using an intravascular contrast agent.