NEW FREQUENCY STEP-TUNABLE ECRH SYSTEM FOR ASDEX UPGRADE

A new broadband ECRH (Electron Cyclotron Resonance Heating) system is currently under construction at the ASDEX Upgrade tokamak. This system will employ multi-frequency gyrotrons step-tunable in the range 105–140 GHz. In its final stage the system will consist of 4 gyrotrons with a total power of 4 MW and a pulse length of 10 s. It employs a fast steerable launcher for feedback controlled deposition that allows for poloidal steering of 10° within 100 ms. Transmission line elements, such as corrugated waveguides, polarizer mirrors and vacuum windows, are designed to cope for this frequency band.     

A fluorine scan at the catalytic center of thrombin: C--F, C--OH, and C--OMe bioisosterism and fluorine effects on pKa and log D values

A series of 16 tricyclic thrombin inhibitors was prepared by using the 1,3-dipolar cycloaddition of azomethine ylides derived from 3- or 4-hydroxyproline and 4-bromobenzaldehyde, with N-(4-fluorobenzyl)maleimide as the key step. The terminal pyrrolidine ring of the inhibitors was systematically substituted to explore the potential bioisosteric behavior of C-F, C-OH, and C-OMe residues pointing into the environment of the catalytic center of a serine protease. X-ray crystal structure analyses revealed a distinct puckering preference of this ring. Substitution by F, HO, and MeO has a strong effect on the basicity of the adjacent pyrrolidine nitrogen center which originates from two sigma-inductive pathways between this center and the electronegative O and F atoms. gem-Difluorination decreases the pKa value of this tertiary amine center to <2, making the conjugated ammonium ion a moderately strong acid. Unexpectedly, F substitution next to the nitrogen center reduced the lipophilicity of the ligands, as revealed by measurements of the logarithmic partition coefficient log D. The biological assays showed that all compounds are thrombin inhibitors with activities between Ki=0.08 and 2.17 microM. Bioisosteric behavior of F, HO, and MeO substituents was observed. Their electronegative F and O atoms undergo energetically similar polar interactions with positively polarized centers, such as the N atom of His 57 which is hydrogen bonded to the catalytic Ser 195. However, for energetically similar polar interactions of C-F, C-OH, and C-OMe to occur, sufficient space is necessary for the accommodation of the Me group of the C-OMe residue, and a H-bond acceptor must be present to prevent unfavorable desolvation of the C-OH residue.     

Mechanics of thin-film transistors and solar cells on flexible substrates

When devices are fabricated on thin foil substrates, any mismatch strain in the device structure makes the work piece curve. Any change of the radius of curvature produces a change in the size of the work piece, and thereby misalignment between individual device layers. To achieve tight tolerances, changes of curvature must be minimized throughout the fabrication process.Amorphous silicon thin-film transistors and solar cells respond differently to externally applied tensile strain. The elastic deformation of the transistor is correlated with small increase in the electron mobility. When the tensile strain reaches 0.34%, crack formation starts and causes an abrupt change in the transistor performance. The performance of solar cells, on the other hand, does not change for tensile strain up to 0.7%. At larger strain the short-circuit current, open-circuit voltage, fill factor, and the efficiency gradually decrease.     

Effect of analgesia during hoof trimming on gait, weight distribution, and activity of dairy cattle

Sixty-six lactating cows were either injected with flunixin meglumine (2.2 mg/kg of BW) immediately before hoof trimming (n = 28), injected with a saline solution immediately before hoof trimming (n = 28), or injected with a saline solution immediately before sham hoof trimming (control; n = 10). Gait scores, time spent lying down, frequency of steps, and how cows distributed their weight among their legs when standing before, during, and after injections were measured to assess whether automated measures of activity and weight distribution can detect lameness and the effects of pain mitigation during hoof trimming. The overall gait score was positively correlated with the variability of the weight applied the rear legs (r = 0.32) and negatively correlated with the rear leg weight ratio (LWR; r = −0.52) and the frequency of steps (r = −0.43). The rear LWR was the best predictor of cows being lame (NRS >3), accounting for 27% of the variation in the likelihood of a cow being lame and 11% of the variation in the likelihood of a cow having an infectious hoof lesion. For each 5% increase in the rear LWR, the likelihood of being lame decreased by 30% (odds ratio = 0.71; 95% confidence interval = 0.56, 0.90) and the likelihood of being afflicted with an infectious hoof disease decreased by 20% (odds ratio = 0.81; 95% confidence interval = 0.67, 0.98). Neither hoof trimming nor a combination of hoof trimming and analgesia significantly affected gait score or any measure of weight distribution. Daily lying time increased during the 2 d following hoof trimming independently of the flunixin meglumine injection. However, this increase was not sustained for longer than 2 d when cows were injected with flunixin meglumine. Measures of weight shifting between legs while cows are standing and measures of activity show great potential as automated methods of detecting lameness and may also provide a tool for future evaluation of lameness therapies, such as hoof trimming and pain mitigation.     

Automated methods for detecting lameness and measuring analgesia in dairy cattle

The objective was to assess gait, automated measures of weight distribution among the legs, and daily activity as methods for detecting lameness in dairy cows and measuring pain mitigation by nonsteroidal antiinflammatory drugs. Fifty-seven lactating cows (28 of which were lame) were injected twice with ketoprofen (3.0 mg/kg i.m.) or isotonic saline solution. Gait scores (numerical rating system, NRS), time spent lying down, frequency of steps, and weight distribution among legs when standing before, during, and after injections were measured to assess whether automated measures of activity can detect lameness and the effect of analgesic drugs in cows. Lame cows (NRS >3) shifted weight between contralateral legs more often (SD of the weight applied: 31.1 ± 2.1 vs. 24.5 ± 1.9 kg), had a greater asymmetry in the weight applied to the rear legs (leg weight ratio = 0.78 ± 0.02 vs. 0.87 ± 0.02), had longer lying bouts (94.0 ± 4.9 vs. 78.2 ± 5.8 min), and walked slower (1.28 ± 0.3 vs. 1.42 ± 0.3 m/s) than nonlame cows. Variability over time (SD) of the weight applied to the rear legs was the most accurate predictor of whether a cow was lame or not (area under the curve = 0.71). The SD of the weight applied to the rear legs decreased on the days when ketoprofen was given compared with the day before and after (18 and 12% decrease for lame and nonlame cows, respectively). Ketoprofen did not affect any other measure. Measures of weight shifting between legs while cows are standing have potential as an automated method of detecting lameness and analgesia.     

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Tribological behaviour of W–Ti–N coatings in semi-industrial strip-drawing tests

W–Ti–N sputtered coatings were tested in semi-industrial conditions by strip drawing to access their ability for sheet metal forming. Both laboratory and industrially developed coatings were tested. In a first part of the study the upscale of the deposition of the W–Ti–N coatings was achieved. The main difference between the two types of coatings was the evolution of the chemical composition with the N content. However, similar trends in the hardness and scratch-test results were encountered being the best compromise of these properties reached for ∼40 at.% N in the industrially deposited films against the 35 at.% N for laboratory deposited ones.