Recent developments of in-vessel calibration of mid-IR cameras at JET.

Recent improvements in software tools and methodology have allowed us to perform a more comprehensive in-vessel calibration for all mid-infrared camera systems at JET. A comparison of experimental methods to calculate the non-uniformity correction is described as well as the linearity for the different camera systems. Measurements of the temperature are assessed for the different diagnostics.

A rotating directional probe for the measurements of fast ion losses and plasma rotation at Tokamak Experiment for Technology Oriented Research.

This work discusses a new directional probe designed for measurements of fast ion losses and the plasma rotation with a high angular resolution in magnetically confined plasmas. Directional and especially Mach probes are commonly used diagnostics for plasma flow measurements, and their applicability for the fast ion losses detection has been demonstrated. A limitation of static Mach probes is their low angular resolution. At the Tokamak Experiment for Technology Oriented Research, the angular resolution is strongly restricted by the finite number of available measurement channels. In a dynamic plasma, where instabilities can lead to local changes of the field line pitch-angle, plasma flow, or fast ion losses, a low angular resolution makes a precise data analysis difficult and reduces the quality of the measured data. The new probe design, the rotating directional probe, combines the features of early directional probes and Mach probes. It consists of two radially aligned arrays of nine Langmuir probe pins with each array facing opposite directions. During the measurement the probe head rotates along its axis to measure the ion saturation current from all directions. As a result, the rotating directional probe simultaneously provides an angular dependent plasma flow and fast ion losses measurement at different radial positions. Based on the angular dependent data, a precise determination of the current density is made. In addition, the simultaneous measurement of the ion saturation current at different radial positions allows for resolving radially varying field line pitch-angles and identifying the radial dynamic of processes like fast ion losses.

Magnetic topology changes induced by lower hybrid waves and their profound effect on edge-localized modes in the EAST tokamak.

Strong mitigation of edge-localized modes has been observed on Experimental Advanced Superconducting Tokamak, when lower hybrid waves (LHWs) are applied to H-mode plasmas with ion cyclotron resonant heating. This has been demonstrated to be due to the formation of helical current filaments flowing along field lines in the scrape-off layer induced by LHW. This leads to the splitting of the outer divertor strike points during LHWs similar to previous observations with resonant magnetic perturbations. The change in the magnetic topology has been qualitatively modeled by considering helical current filaments in a field-line-tracing code.

Experimental observation of a magnetic-turbulence threshold for runaway-electron generation in the TEXTOR tokamak.

Magnetic turbulence is observed at the beginning of the current quench in intended TEXTOR disruptions. Runaway electron (RE) suppression has been experimentally found at magnetic turbulence larger than a certain threshold. Below this threshold, the generated RE current is inversely proportional to the level of magnetic turbulence. The magnetic turbulence originates from the background plasma and the amplitude depends strongly on the toroidal magnetic field and plasma electron density. These results explain the previously found toroidal field threshold for RE generation and have to be considered in predictions for RE generation in ITER.

Upgrade of the infrared camera diagnostics for the JET ITER-like wall divertor.

For the new ITER-like wall at JET, two new infrared diagnostics (KL9B, KL3B) have been installed. These diagnostics can operate between 3.5 and 5 µm and up to sampling frequencies of ∼20 kHz. KL9B and KL3B image the horizontal and vertical tiles of the divertor. The divertor tiles are tungsten coated carbon fiber composite except the central tile which is bulk tungsten and consists of lamella segments. The thermal emission between lamellae affects the surface temperature measurement and therefore KL9A has been upgraded to achieve a higher spatial resolution (by a factor of 2). A technical description of KL9A, KL9B, and KL3B and cross correlation with a near infrared camera and a two-color pyrometer is presented.

Diffusion in a collisional standard map.

Test particle evaluation of the diffusion coefficient in the presence of magnetic field fluctuations and binary collisions is presented. Chaotic magnetic field lines originate from resonant magnetic perturbations (RMPs). To lowest order, charged particles follow magnetic field lines. Drifts and interaction (collisions) with other particles decorrelate particles from the magnetic field lines. We model the binary collision process by a constant collision frequency. The magnetic field configuration including perturbations on the integrable Hamiltonian part is such that the single particle motion can be followed by a collisional version of a Chirikov-Taylor (standard) map. Frequent collisions are allowed for. Scaling of the diffusion beyond the quasilinear and subdiffusive behaviour is investigated in dependence on the strength of the magnetic perturbations and the collision frequency. The appearance of the so called Rechester-Rosenbluth regime is verified. It is further shown that the so called Kadomtsev-Pogutse diffusion coefficient is the strong collisional limit of the Rechester-Rosenbluth formula. The theoretical estimates are supplemented by numerical simulations.

Placebo-controlled, randomized, evaluator-blinded endoscopy study of risedronate vs. aspirin in healthy postmenopausal women.

BACKGROUND: Bisphosphonates are effective treatments for osteoporosis. Since some primary amino bisphosphonates are associated with oesophageal injury, we conducted a study of the upper gastrointestinal effects of risedronate, a pyridinyl bisphosphonate. METHODS: Healthy, postmenopausal women received risedronate 5 mg (n=26), aspirin 2600 mg (n=27), or placebo (n=27) daily for 14 days and underwent endoscopy at baseline, Day 8 and Day 15. RESULTS: Oesophageal erosions were noted in one subject in the aspirin group, two in the placebo group, and none in the risedronate group, and an ulcer in one aspirin-treated subject. Gastric erosions and ulcers were observed most frequently in the aspirin group. Gastric ulcers were noted in eight subjects in the aspirin group, one in the placebo group, and none in the risedronate group (P=0.010, placebo vs. aspirin; P=0.002, risedronate vs. aspirin). Duodenal erosions and ulcers were observed in the aspirin group only. Gastroduodenal erosion scores of three or more occurred more frequently in the aspirin than in the risedronate and placebo groups (P < 0.001). CONCLUSIONS: Risedronate 5 mg was not associated with oesophageal or gastroduodenal ulcers in healthy, postmenopausal women, a population representative of patients who will receive risedronate in the clinical setting.

Specific inhibition of cyclooxygenase-2 with MK-0966 is associated with less gastroduodenal damage than either aspirin or ibuprofen.

BACKGROUND: Compared with currently available NSAIDs (which inhibit COX-1 and COX-2 isoforms of cyclooxygenase), MK-0966 (a specific COX-2 inhibitor) is expected to cause less gastrointestinal toxicity. AIM: To compare the effect on the upper gastrointestinal mucosae of a high dose of MK-0966 with that of conventional doses of ibuprofen and aspirin. METHODS: Healthy subjects (n = 170; age range 18-54 years) with endoscopically normal gastric and duodenal mucosa were randomized to either MK-0966 250 mg q.d. (n = 51), ibuprofen 800 mg t.d.s. (n = 51), aspirin 650 mg q.d.s. (n = 17), or placebo (n = 51) in this 7-day, double-blind, parallel-group study. The mucosae were evaluated by endoscopy using a predefined scale; scores could range from 0 to 4. The primary end-point was the percentage of subjects who developed a mucosal score >/= 2 (i.e. the development of one or more erosions). To evaluate COX-1 activity, serum thromboxane B2 levels were determined in a subset of the population. RESULTS: The percentage of subjects who developed a mucosal score >/= 2 in the MK-0966 group (12%) was significantly lower (P < 0.001) than that in the ibuprofen (71%) and aspirin (94%) groups, and was similar to that in the placebo group (8%). Only ibuprofen and aspirin significantly (P < 0.0001) reduced baseline thromboxane B2 levels. All treatments were generally well tolerated. CONCLUSIONS: In this acute short-term endoscopic study, MK-0966 250 mg q.d. (a dose at least 10 times higher than that demonstrated to reduce the signs and symptoms of osteoarthritis) produced significantly less gastrointestinal mucosal damage than either ibuprofen 800 mg t.d.s. or aspirin 650 mg q.d.s. and was comparable to placebo in this regard.

Effects of alendronate on gastric and duodenal mucosa.

OBJECTIVES: This single-center, double-blind, randomized study assessed the effect of alendronate 5 and 10 mg on the gastroduodenal mucosa. METHODS: Overall, 95 postmenopausal women without a recent history of major upper gastrointestinal (GI) disease and not taking gastric-irritant drugs, were screened with an upper GI endoscopy. Fourteen women (15% of the total) were found to have baseline endoscopic gastric and/or duodenal abnormalities, including mucosal hemorrhages (n = 4), erosions (n = 11), and ulcers (n = 3). Two additional women had baseline esophageal abnormalities. Thus, 79 postmenopausal women (mean age 51 yr, range 41-64 yr), free of esophageal, gastric and/or duodenal erosions or ulcer, were enrolled. Subjects received placebo, alendronate 5 mg/day or 10 mg/day, or aspirin 650 mg q.i.d. for 14 days. Endoscopy was repeated on Day 8 and on Day 15. Gastric and duodenal mucosae were graded separately using a 5-point scale for erosive mucosal injury. RESULTS: The proportions of subjects with a gastric or duodenal erosion score > or = 2 (presence of at least one mucosal erosion) on either Day 8 or 15 were four of 22 (18.2%) in the placebo group; four of 22 (18.2%) in the alendronate 5 mg group; five of 21 (23.8%) in the alendronate 10 mg group; and 14 of 14 (100.0%) in the aspirin group. Thirty-five of 76 (46%) subjects were H. pylori-positive (Pyloritek test), and were equally distributed across treatment groups. CONCLUSIONS: Alendronate 5 and 10 mg/day for 2 wk was associated with a lower incidence of gastric erosions than aspirin. The incidence of gastric erosions in the alendronate groups did not differ significantly from the placebo group. In this study, unlike aspirin, alendronate did not induce gastric erosions.

Cytochemical localization of guanylate cyclase in photoreceptor cells of the mouse.

BACKGROUND: Light-stimulated excitation causes a decrease of the cGMP concentration in vertebrate photoreceptor cells. The cGMP content is restored by the catalytic action of a guanylate cyclase (EC 4.6.1.2). METHODS: The spatial distribution of guanylate cyclase was determined cytochemically in rod visual cells of the mouse. RESULTS: In retinal tissue of the mouse guanylate cyclase was found throughout the photoreceptor cells, in the outer and the inner segments, and was especially prominent in the cilia and in elongations of cilia extending into the outer segments. A reaction product of adenylate cyclase (EC 4.6.1.1) could not be demonstrated in vertebrate rod outer segments. CONCLUSION: The relatively high amount of guanylate cyclase in the inner segments and the cilia may contribute-at least in part-to the actual concentration and the time course of concentration changes of the cGMP concentration in rod outer segments.

Interaction of guanosine 5'-triphosphate binding protein Gq from Sepia officinalis with illuminated rhodopsin bound to concanavalin A.

The heterotrimeric guanosine 5'-triphosphate (GTP)-binding protein Gq was suggested to couple the light receptor rhodopsin with the effector phospholipase C in visual cells of invertebrates. We indirectly linked Gq from Sepia officinalis to a concanavalin A-sepharose column via rhodopsin. Rhodopsin had been solubilized previously with 10 mM n-dodecyl-beta-maltoside from the purified photosensory membrane under illumination. All three subunits of the Gq were released almost pure by elution with 100 microM GTP. The alpha and beta subunits were identified by specific antipeptide antisera. The alpha subunit has a relative molecular mass of 46 kDa, and the beta subunit of 35 kDa. The gamma subunit corresponds to a 9 kDa polypeptide owing to the molecular mass, which is similar to the G gamma subunit of squid. The use of specific antibodies shows that neither actin nor G-protein related to transducin were in the fractions eluted with GTP or alpha-methyl mannoside. We demonstrate that all three subunits of Gq were associated with rhodopsin of invertebrates. Such use of a lectin column might be useful for further investigations of the interaction of rhodopsin and Gq.

Heterogeneous ultrastructure of melanosome formation in the goldfish induced by osmotic stress.

In this study, melanophore cytodifferentiation in the fins of xanthic goldfish that had been exposed to osmotic stress for 18 days was investigated. It was found that multi-vesicular bodies (MVB) are not the only type of premelanosome. Granules having a homogeneous matrix also function as premelanosomes. The presence of acid phosphatase reaction product inside the melanin granules indicated that these organelles in this animal were also related to lysosomes. DOPA-oxidase of tyrosinase, the key enzyme in melanogenesis, was surprisingly not only detected in melanocytes but also in the Golgi stacks of dermal cells. Due to the mechanisms of premelanosome formation it is evident that cytoplasmic material also serves as substrate for melanogenesis. EDX microanalysis was performed to measure the ionic composition of the melanin granules. After aldehyde fixation the newly-formed melanin granules did not contain Na, but had accumulated Ca.

Immunoelectron-microscopic study of G-protein distribution in photoreceptor cells of the cephalopod Sepia officinalis.

Previous studies suggest that more than one single light-stimulated transduction pathway seems to be present in photoreceptor cells of invertebrates. Accordingly, more than one light-dependent G-protein has been detected in squid photoreceptor cells. Two different antibodies were used to locate the distribution of G-proteins in Sepia photoreceptors. One antiserum (anti-G alpha-common) has been raised against the peptide CGAGESGKSTIVKQMK. This sequence is found in most G alpha-protein subunits, it is also present in transducin of vertebrates. This sequence however, is conserved only partially in G alpha q from photosensory membranes of the squid. The second antiserum (anti-G alpha q) has been raised against the peptide QLNLKEYNLV. This sequence is present at the C-terminus of e.g. G alpha q from mouse brain and is identical also in squid. Anti-G alpha q very strongly interacted with the rhabdomeres of the photoreceptor cells from Sepia. In the non-rhabdomeric cytoplasm of the photoreceptor cells gold granules (bound to the second antibody) were almost absent. With anti-G alpha-common, only a small number of gold particles could be found at the rhabdomeres. The non-rhabdomeric cytoplasm was not labelled. Thus, further G-proteins that might be involved in a light dependent phototransduction mechanism besides the phosphoinositide pathway can hardly be expected to belong to the group of 'common' G-proteins.

On the Ca(2+)-dependence of inositol-phospholipid-specific phospholipase C of microvillar photoreceptors from Sepia officinalis.

The breakdown of phosphatidylinositol 4,5-bisphosphate (PIP2) by the action of a phosphoinositide-specific phospholipase C is a key event in the signal transduction mechanism of microvillar photoreceptors. The enzymatic activity of phospholipase C from photoreceptor cell membranes of the cuttlefish Sepia officinalis was measured at different concentrations of free calcium. A bell-shaped curve with a maximum of enzyme activity at about 0.2 to 0.7 microM of free calcium was obtained. In the range of 10 to 90 microM free Ca2+, the activity of the phospholipase C decreased to about 30%. The activity of the phospholipase was also modulated by strontium ions. The presence of 10 microM Sr2+ strongly reduced the dependence of the phospholipase from a given calcium concentration. Similarly to 10 mM EGTA, the presence of 10 microM La3+ reduced the enzymatic activity more than ten-fold. A comparison of these values with the changes of the calcium concentration measured in ventral photoreceptor cells of Limulus polyphemus in the dark (approximately 0.5 microM Ca2+) and under illumination (up to 30-100 microM Ca2+) indicates that in microvillar photoreceptor cells an elevation of the calcium concentration in the physiological range reduces the activity of the phospholipase C. The IP3 produced by the action of phospholipase C is known to elevate the intracellular Ca2+ concentration transiently, which in turn will be able to reduce the further IP3 formation. A negative feedback in this early part of the enzyme cascade of vision in invertebrates may substantially contribute to the process of adaptation.

Cyclic 3',5'-nucleotide phosphodiesterase: cytochemical localization in photoreceptor cells of the fly Calliphora erythrocephala.

The distribution of cyclic 3',5'-nucleotide phosphodiesterase activity was determined in photoreceptor cells of the fly Calliphora erythrocephala. With cAMP as substrate, staining was most intense within the phototransducing region of these cells, the rhabdomeral microvilli and also in the extracellular space surrounding the microvilli and in the mitochondria. With cGMP as substrate, the intensity within the rhabdomeres was less marked, while their extracellular surroundings were stained heavily. Thus, compared to cGMP, cAMP is the better substrate for the phosphodiesterase in the rhabdomeres of the fly. For comparison, the same cytochemical method was used to localize the well-known phosphodiesterase activity in retinal tissue of the mouse. Under the same conditions as used for fly photoreceptors, a very intense reaction product was obtained in rod outer segments. With regard to the conflicting reports concerning the light-stimulated changes of cyclic nucleotides in invertebrate photoreceptor cells, the results presented here further argue for an important role of a cyclic nucleotide in the process of phototransduction of invertebrates.

Isolation of the rhabdomeral microvillar cytoskeleton of the crayfish (Orconectes limosus) photoreceptor by a crosslinking reagent.

1. Rhabdomeral microvilli of photoreceptor cells of invertebrates contain a labile central cytoskeleton. For stabilization of the rhabdomeral cytoskeleton of the crayfish Orconectes limosus the crosslinking reagent suberic acid bis (N-hydroxysuccinimide ester) was used. 2. It was found that this crosslinking reagent can be successfully used to stabilize and isolate the microvillar cytoskeleton of crayfish photoreceptors. 3. After detergent treatment cytosolic proteins and the cell membranes were removed. 4. By the combined use of crosslinker and detergent the accessibility of antibodies or other markers to the microvillar cytoskeleton is possible. 5. This method may be useful, because at present little is known about the proteins associated with the central filament of invertebrate photoreceptors.

Endoscopic comparison of cimetidine and sucralfate for prevention of naproxen-induced acute gastroduodenal injury. Effect of scoring method.

Nonsteroidal antiinflammatory drug-induced gastroduodenal mucosal damage observed endoscopically is usually categorized as hemorrhages, erosions, or ulcerations. We undertook this study to determine whether the injury produced by a commonly prescribed NSAID, naproxen, could be reduced by cotherapy with sucralfate or cimetidine and to determine how dependent the differences in the degree of protection against mucosal injury measured were on the scoring system used. Four groups of 20 healthy volunteers with endoscopically normal gastric and duodenal mucosa received naproxen (500 mg twice a day) plus cimetidine (300 mg four times a day or 400 mg twice a day), sucralfate (1 g four times a day), or placebo for seven days. After seven days of therapy, a second endoscopy was performed. Separate scoring systems were used for the presence of hemorrhages, erosions, and a combination of both types of injury. There were significantly fewer mucosal hemorrhages present when naproxen and cimetidine were administered than when naproxen was administered with placebo or sucralfate (placebo vs 300 mg cimetidine, P = 0.04, and placebo vs 400 mg cimetidine, P = 0.006, placebo vs sucralfate, P = 0.26). Both cimetidine dosages resulted in significantly fewer hemorrhages than were present following cotherapy of naproxen and sucralfate (P less than 0.05). In contrast, there was no discernible difference in the mucosal injury between placebo and any drug or between any two active therapies when the injury was evaluated based on the presence of gastric erosions.(ABSTRACT TRUNCATED AT 250 WORDS)

An endoscopic comparison of the gastroduodenal injury seen with salsalate and naproxen.

Forty endoscopically normal healthy subjects were randomized to receive either BID salsalate (3500 mg/day) or BID naproxen (750 mg/day) for 14 days followed by repeat endoscopic examination. Gastroduodenal lesions were found in 55% (11/20) of the subjects taking naproxen, and 10% (2/20) of those taking salsalate (p = 0.002). Twenty-five percent (5/20) of the subjects taking naproxen and none of the subjects taking salsalate were noted to have severe gastric injury (p = 0.003). There was no difference between the 2 groups in subjective gastrointestinal system adverse experiences. Overall, 95% (19/20) of subjects taking salsalate reported at least 1 adverse experience compared with 60% (12/20) of those taking naproxen (p = 0.02). This was due primarily to the higher number of subjects taking salsalate reporting reversible tinnitus or hearing loss. There was no significant treatment difference in adverse experiences reported for any other organ system. The results of our study support previous observations in patients with rheumatoid arthritis that salsalate produces less gastroduodenal mucosal toxicity than the widely used antiinflammatory agent, naproxen.

The effect of bismuth subsalicylate on the histologic gastritis seen with Campylobacter pylori: a placebo-controlled, randomized study.

In order to assess whether bismuth subsalicylate (BSS) clears Campylobacter pylori and whether this clearance is associated with improvement in histologic gastritis, 20 patients with antral biopsies colonized by C. pylori were randomized to treatment with 30 ml of BSS (525 mg) or placebo q.i.d. for 21 days. After both 2 and 3 wk of treatment, C. pylori was cleared in 70% (7/10) of BSS-treated patients, compared with 10% (1/10) of patients on placebo (p less than 0.05) at 2 wk and 0% (0/10) of patients on placebo at 3 wk (p less than 0.01). A significant improvement in histologic gastritis (p less than 0.05) was noted after 2 and 3 wk of treatment in the group receiving BSS. Gastritis improvement was a result of both reduced polymorphonuclear and mononuclear cell infiltration. Clearance of C. pylori was highly correlated with improvement of histologic gastritis (p less than 0.001). In addition, mucus depletion scores were significantly improved in the BSS-treated group. These data indicate that treatment with BSS provides short-term clearance of C. pylori in antral mucosa, and this clearance is associated with an improvement in histologic gastritis. These findings support the pathogenic role of C. pylori in histologic antral gastritis.

A double-blind placebo-controlled comparison of the efficacy and safety of 50, 100, and 200 micrograms of misoprostol QID in the prevention of ibuprofen-induced gastric and duodenal mucosal lesions and symptoms.

Ibuprofen, a commonly proscribed nonsteroidal anti-inflammatory drug that is also available in many countries, including the United States, without a prescription, is known to cause hemorrhage and erosion of the gastroduodenal mucosa. This study was conducted to compare the efficacy of 200, 100, and 50 micrograms of misoprostol and placebo administered qid for 6 days, with a final dose on the morning of the 7th day, in the prevention of gastric and duodenal lesions induced by the concurrent administration of 800 mg of ibuprofen qid. A total of 120 healthy subjects with endoscopically normal gastric and duodenal mucosae were enrolled in the study. The endoscopic examination was repeated 2 h after the final dose on day 7, and the mucosae were graded on a 0 to 4+ scale. In the stomach, all three misoprostol groups were significantly more protective than placebo and did not differ significantly from each other. In the duodenum, the endoscopic scores of the 200- and 100-micrograms misoprostol groups, but not the 50-micrograms group differed significantly from placebo. The 200- and 100-microgram groups did not differ significantly from each other, but both differed from the 50-micrograms group for duodenal mucosal injury. Subjective symptoms thought to be primarily attributable to the NSAID (e.g., pain, indigestion/heartburn and nausea) were recorded by each subject in a diary. Subjects in the 200-micrograms misoprostol group attained the greatest degree of mucosal protection and had a significantly higher incidence of indigestion/heartburn and abdominal pain than the placebo group. One can conclude that misoprostol in both antisecretory (200- and 100-micrograms) and non-antisecretory (50-micrograms) doses protects the gastric mucosa from injury from high anti-inflammatory doses of ibuprofen (3200 mg/day). Only the antisecretory doses (100 and 200 micrograms qid) were effective in the duodenum, suggesting that acid suppression is necessary for mucosal protection to occur in the duodenum.