Impact of full-scale brewing processes on lager beer nitrogen compounds

This paper analyses in a full-scale industrial process firstly the nitrogen compounds in all-malt and in maize-adjunct worts, then their fate during the main brewing steps and finally the influence on them of two different separation technologies: mash filter (Meura 2001) and lauter tun (Steinecker FVAS 26). Data showed that (1) maize-adjunct worts have a lower total nitrogen compounds than all-malt worts; (2) assimilable nitrogen represents 20–24% out of the total nitrogen in both all-malt and in adjunct worts; (3) free amino nitrogen nearly doubles in all-malt compared with adjunct worts; (4) proline and asparagine are the most abundant amino acids in both worts; (5) ammonium disappears during fermentation in wort with the lowest nitrogen content, i.e. in maize-adjunct wort. Moreover, the total nitrogen is reduced in all-malt by 80% with the Steinecker FVAS 26 lauter tun and 25% with the Meura 2001 filter, while in adjunct worts by 87% with the Steinecker FVAS 26 lauter tun and 29% with the Meura 2001 filter. After mash filtration, the content of assimilable nitrogen remains to be adequate for an efficient fermentation, but after lauter tun separation, the assimilable nitrogen reaches values that may compromise the regular fermentation process in both all-malt and adjunct worts. Therefore, when using lauter tun, we have to intervene to reduce its impact on nitrogen compounds and/or plan the wort nitrogen supplementation to overcome the stuck and sluggish fermentations.     

Projection method of resolving ambiguities by determining the order of colors in moiré fringes

From the scientific literature there are some well-known methods used to resolve the arising problem of ambiguities in moiré patterns. The main disadvantage of these methods is that for image processing one must use several patterns. It means that it is impossible to work with dynamic objects in a real-time operation mode. We present a projection method to resolve ambiguities by determining the order of colors in moiré patterns. This method is based on the application of color rulings to gratings in a projection moiré technique.     

High-contrast images of semiconductor sites via one-photon optical beam-induced current imaging and confocal reflectance microscopy

We demonstrate a computationally efficient procedure for determining only the semiconductor sites in a confocal reflectance image of an integrated circuit. It utilizes a one-photon optical beam-induced current (1P-OBIC) and confocal reflectance images that are generated from the same focused excitation beam. A 1P-OBIC image is a two-dimensional map of the currents induced by the beam as it is scanned across the circuit surface. A 1P-OBIC is produced by an illuminated semiconductor material if the excitation photon energy exceeds the bandgap. The 1P-OBIC image has no vertical resolution because the 1P-OBIC is linear with the excitation beam intensity. The exclusive high-contrast image of semiconductor sites is generated by the product of the 1P-OBIC image and the confocal image. High-contrast images of the metal sites are also obtained by the product of the complementary OBIC image and the same confocal image.     

Binding mode of TMC-95A analogues to eukaryotic 20S proteasome

The complex thermodynamics that govern noncovalent protein-ligand interactions are still not fully understood, despite the exponential increase in experimental structural data available from X-ray crystallography and NMR spectroscopy. The eukaryotic 20S proteasome offers an ideal system for such studies as it contains in duplicate three proteolytically active sites with different substrate specificities. The natural product TMC-95A inhibits these proteolytic centers noncovalently with distinct affinities. X-ray crystallographic analysis of the complexes of the yeast proteasome core particle with this natural inhibitor and two synthetic analogues clearly revealed highly homologous hydrogen-bonding networks involving mainly the peptide backbone despite the strongly differentiated binding affinities to the three active sites of the 20S proteasome. The natural product and the two analogues are constrained in a rigid beta-type extended conformation by the endocyclic biaryl clamp, which preorganizes the peptide backbone for optimal adaptation of the ligands to the active site clefts and thus favors the binding processes entropically. However, the biaryl clamp also dictates the orientation of the P1 and P3 residues and their mode of interaction with the protein binding subsites. This limitation is optimally solved in TMC-95A with the conformationally restricted (Z)-prop-1-enyl group acting as P1 residue, at least for the chymotrypsin-like active site; however, it critically affects the inhibitory potencies of the analogues, thus suggesting the use of less-rigid endocyclic clamps in the design of proteasome inhibitors that allow for a better presentation of residues interacting with the active site clefts of the enzyme.     

Spatial light modulator-controlled alignment and spinning of birefringent particles optically trapped in an array

We demonstrate the use of a phase-only liquid-crystal spatial light modulator (SLM) for polarization-controlled rotation and alignment of an array of optically trapped birefringent particles. A collimated beam incident upon a two-dimensional lenslet array yields multiple foci, scaled to produce optical gradient traps with efficient three-dimensional trapping potentials. The state of polarization of each trapping beam is encoded by the SLM, which acts as a matrix of wave plates with computer-controlled phase retardations. Control of the rotation frequency and alignment direction of the particles is achieved by the transfer of tunable photon spin angular momentum.     

Comment: Influence of illuminating beyond the object support on Zernike-type phase contrast filtering

In this comment, we clarify some serious misinterpretations that can arise from an uncritical use of the results presented in [Appl. Opt. 41, 2607, (2002)]. In particular, we point out that their suggestion of using "illumination beyond the object support" for measuring phase disturbances can result in distorted or strongly inaccurate interference patterns. We also point out that Llave and Castillo have misinterpreted our previous work describing the effect of phase object fill factor on the output interference patterns, which is in fact one of the key factors considered in the generalized phase contrast (GPC) method. Unlike the Zernike method, the GPC method results in an optimized visualization of the phase disturbance by the achievement of a matching condition between the applied filter and the spatial average of a given phase disturbance, thereby implying the optimal use of fill factor information.     

Clinical and biochemical features of muscle dysfunction in subclinical hypothyroidism

Alterations in muscle structure and function have been reported in overt hypothyroidism, with decreased activity of enzymes involved in anaerobic and oxidative glucose metabolism. To test whether similar changes in muscle energy metabolism are present in subclinical hypothyroidism (sHT), we studied 12 patients with sHT who complained of mild neuromuscular symptoms. The control group included 10 sex- and age-matched healthy volunteers. Skeletal muscle lactate and pyruvate production were determined in the resting state and during dynamic arm exercise. During exercise, blood lactate was significantly higher in sHT patients than in controls from the third exercise step onward (P = 0.02 at 30%, p = 0.008 at 40%, and P = 0.002 at 50% of maximal voluntary contraction). Moreover, the mean increment in blood lactate during exercise was positively related (r2 = 0.44; P = 0.02) to the duration of sHT, but not to serum levels of TSH, free T3, or free T4. No significant difference was found in blood pyruvate concentrations between the two groups at baseline or during exercise. Thus, the lactate/pyruvate ratio curve paralleled the lactate curve in patients as well as controls. We conclude that muscle energy metabolism is impaired in sHT in rough proportion to the known duration of the disease. Early L-T4 therapy may be useful not only to provide specific treatment for such metabolic changes, but also to avoid progression to frank hypothyroidism.     

The Tricept robot: dynamics and impedance control

The Tricept is a novel industrial robot characterized by a hybrid kinematic design featuring a three-degrees-of-freedom (3-DOF) structure of parallel type and a 3-DOF spherical wrist. In this work the authors focus on the derivation of a dynamic model to be used for both simulation and control purposes. Two different approaches are discussed and compared in terms of inverse dynamics computation. Then, a model-based control is derived aimed at enforcing a 6-DOF impedance behavior at the end effector to manage interaction with the environment. Simulation results are presented to evaluate the accuracy of an approximate dynamic model computation as well as to test the effectiveness of the proposed impedance control strategy.     

An output feedback parallel force/position regulator for a robot manipulator in contact with a compliant environment

In this paper the problem of regulating force and position for a robot manipulator in contact with an elastically compliant environment is considered. In the framework of parallel force/position control, an output feedback regulator with gravity compensation and desired force feedforward is proposed which only requires measurements of force and position. Semiglobal stability of the closed-loop system around the equilibrium is shown via a Lyapunov argument.