Parameter identification for discrete element simulation of vertical filling: in-situ bulk calibration for realistic granular foods

Vertical filling of granular media is influenced by resistance of the surrounding medium, especially in the case of a dilute process with relatively large distances between particles and relatively low particle densities. Discrete Element simulations were carried out to calibrate models of such a filling process for two granular food goods. The aim was to perform bulk calibration in-situ, meaning in the process of interest itself, rather than a second setup. To account for the air drag but keep computational cost practical, the computationally cheap free fall was modeled with the Schiller-Naumann correlation for drag force. The predictions where compared to simulations without fluid influence. The results show that the predictive quality of the models was increased with the simple drag model. It is shown that with the expanded model, calibration can be performed in the filling process itself, which might be useful especially for industry application

Bildkontraste im menschlichen Muskelgewebe und Beugungsphänomene in der 1H-NMR infolge individueller und kollektiver Dipol-Dipol-Wechselwirkungen von Wasserprotonen in flüssiger Phase

Individuelle und kollektive 1H-Dipol-Dipol-Wechselwirkungen in der NMR von Flüssigkeiten eröffnen neue Ansätze zur Untersuchung von mikroskopischen Strukturen. In der CRAZED-Pulssequenz (zwei HF-Pulse, Zeitintervall τ, Gradient G) führen kollektive Dipol-Dipol-Wechselwirkungen zwischen Protonen mit einem Abstand d= π/(γGτ) zu intermolekularen Mehrquantenkohärenzen. Die Korrelationsdistanz d ist über die Stärke eines Gradienten einstellbar und beträgt typischerweise 1mm…0,1mm. Die variable Abstandsabhängigkeit eröffnet prinzipiell die Möglichkeit, strukturierte Proben zu vermessen. Mit Hilfe von periodisch strukturierten Phantomen konnte die Abstandsabhängigkeit verifiziert werden. Weiterhin konnte gezeigt werden, daß die CRAZED-Signale das Fourierspektrum der untersuchten Probe reflektieren. Ähnlich wie bei konventionellen Streuexperimenten erhält man Information über die Wellenzahlen der untersuchten Struktur. Um das CRAZED-Experiment für MRT-Studien verfügbar zu machen, wurden verschiedene CRAZED-MR-Bildgebungstechniken auf einem klinischen 1,5T-Ganzkörper-Tomographen implementiert, mit denen In-vivo-Bilder vom Kopf von Probanden aufgenommen werden konnten. Die CRAZED-Pulssequenz bietet für die MRT einen neuen, vom Abstand zweier Kernspins abhängigen Kontrastparameter. In verschiedenen biologischen Gewebstypen (z.B. Sehnen, Muskelgewebe, Knorpelgewebe, Nervengewebe) resultieren individuelle 1H-Dipol-Dipol-Wechselwirkungen aus bewegungsgehemmten Protonen. Ursache der Bewegungshemmung sind kurzeitige Bindungen der Protonen an eine makromolekulare Matrix (z.B. Proteine) oder chemischer Austausch mit dieser. Um den Anteil der bewegungsgehemmten Protonen in einer MR-Bildgebung selektiv aufzunehmen, wurde der Unterschied zwischen den beiden transversalen Relaxationszeiten T2 und T2 ρ genutzt. Die Technik basiert auf der Signaldifferenz einer synchronisierten Spinecho- und „Magic Sandwich Echo“-Aufnahme. Mit Hilfe von Agar-Gel-Phantomen konnte das Verfahren verifiziert werden. In-vivo-Aufnahmen an der Wade von Probanden konnten damit aufgenommen werden. In Untersuchungen der oben genannten Gewebstypen könnte dieses Verfahren von Nutzen für die Diagnostik sein

Complex Evolution of a Y-Chromosomal Double Homeobox 4 (DUX4)-Related Gene Family in Hominoids

The human Y chromosome carries four human Y-chromosomal euchromatin/heterochromatin transition regions, all of which are characterized by the presence of interchromosomal segmental duplications. The Yq11.1/Yq11.21 transition region harbours a peculiar segment composed of an imperfectly organized tandem-repeat structure encoding four members of the double homeobox (DUX) gene family. By comparative fluorescence in situ hybridization (FISH) analysis we have documented the primary appearance of Y-chromosomal DUX genes (DUXY) on the gibbon Y chromosome. The major amplification and dispersal of DUXY paralogs occurred after the gibbon and hominid lineages had diverged. Orthologous DUXY loci of human and chimpanzee show a highly similar structural organization. Sequence alignment survey, phylogenetic reconstruction and recombination detection analyses of human and chimpanzee DUXY genes revealed the existence of all copies in a common ancestor. Comparative analysis of the circumjacent beta-satellites indicated that DUXY genes and beta-satellites evolved in concert. However, evolutionary forces acting on DUXY genes may have induced amino acid sequence differences in the orthologous chimpanzee and human DUXY open reading frames (ORFs). The acquisition of complete ORFs in human copies might relate to evolutionary advantageous functions indicating neo-functionalization. We propose an evolutionary scenario in which an ancestral tandem array DUX gene cassette transposed to the hominoid Y chromosome followed by lineage-specific chromosomal rearrangements paved the way for a species-specific evolution of the Y-chromosomal members of a large highly diverged homeobox gene family

SMATASY - A program for the model independent description of the Z resonance

SMATASY is an interface for the ZFITTER package and may be used for the model independent description of the Z resonance at LEP 1 and SLC. It allows the determination of the Z mass and width and its resonance shape parameters r and j for cross-sections and their asymmetries. The r describes the peak height and j the interference of the Z resonance with photon exchange in each scattering channel and for $\sigma_T$, $\sigma_{FB}$, $\sigma_{lr}$, $\sigma_{pol}$ etc. separately. Alternatively, the helicity amplitudes for a given scattering channel may be determined. We compare our formalism with other model independent approaches. The model independent treatment of QED corrections in SMATASY is applicable also far away from the Z peak.Comment: 25 pages (LaTeX), 5 figures, 1 table, see also http://www-zeuthen.desy.de/~riemann/ or http://hpl3sn02.cern.ch/homepages/gruenew

Electron localization by self-assembled GaSb/GaAs quantum dots.

We have studied the photoluminescence from type-II GaSb/GaAs self-assembled quantum dots in magnetic fields up to 50 T. Our results show that at low laser power, electrons are more weakly bound to the dots than to the wetting layer, but that at high laser power, the situation is reversed. We attribute this effect to an enhanced Coulomb interaction between a single electron and dots that are multiply charged with holes

Applicability of correlated digital image correlation and infrared thermography for measuring mesomechanical deformation in foams and auxetics

Cellular materials such as metal foams or auxetic metamaterials are interesting microheterogeneous materials used for lightweight construction and as energy absorbers. Their macroscopic behavior is related to their specific mesoscopic deformation by a strong structure-property-relationship. Digital image correlation and infrared thermography are two methods to visualize and study the local deformation behavior in materials. The present study deals with the full-field thermomechanical analysis of the mesomechanical deformation in Ni/PU hybrid foams and Ni/polymer hybrid auxetic structures performing a correlative digital image correlation and infrared thermography. Instead of comparing and correlating only the primary output variables of both methods, strain and temperature, also strain rates and temperature rates occurring during deformation were compared. These allow for a better correlation and more conclusive results than obtained using only the primary output variables

Development of human antibody fragments using antibody phage display for the detection and diagnosis of Venezuelan equine encephalitis virus (VEEV)

<p>Abstract</p> <p>Background</p> <p>Venezuelan equine encephalitis virus (VEEV) belongs to the Alphavirus group. Several species of this family are also pathogenic to humans and are recognized as potential agents of biological warfare and terrorism. The objective of this work was the generation of recombinant antibodies for the detection of VEEV after a potential bioterrorism assault or an natural outbreak of VEEV.</p> <p>Results</p> <p>In this work, human anti-VEEV single chain Fragments variable (scFv) were isolated for the first time from a human naïve antibody gene library using optimized selection processes. In total eleven different scFvs were identified and their immunological specificity was assessed. The specific detection of the VEEV strains TC83, H12/93 and 230 by the selected antibody fragments was proved. Active as well as formalin inactivated virus particles were recognized by the selected antibody fragments which could be also used for Western blot analysis of VEEV proteins and immunohistochemistry of VEEV infected cells. The anti-VEEV scFv phage clones did not show any cross-reactivity with Alphavirus species of the Western equine encephalitis virus (WEEV) and Eastern equine encephalitis virus (EEEV) antigenic complex, nor did they react with Chikungunya virus (CHIKV), if they were used as detection reagent.</p> <p>Conclusion</p> <p>For the first time, this study describes the selection of antibodies against a human pathogenic virus from a human naïve scFv antibody gene library using complete, active virus particles as antigen. The broad and sensitive applicability of scFv-presenting phage for the immunological detection and diagnosis of Alphavirus species was demonstrated. The selected antibody fragments will improve the fast identification of VEEV in case of a biological warfare or terroristic attack or a natural outbreak.</p

Concepts and clinical aspects of active implants for the treatment of bone fractures

Nonunion is a complication of long bone fractures that leads to disability, morbidity and high costs. Early detection is difficult and treatment through external stimulation and revision surgery is often a lengthy process. Therefore, alternative diagnostic and therapeutic options are currently being explored, including the use of external and internal sensors. Apart from monitoring fracture stiffness and displacement directly at the fracture site, it would be desirable if an implant could also vary its stiffness and apply an intervention to promote healing, if needed. This could be achieved either by a predetermined protocol, by remote control, or even by processing data and triggering the intervention itself (self-regulated ‘intelligent’ or ‘smart’ implant). So-called active or smart materials like shape memory alloys (SMA) have opened up opportunities to build active implants. For example, implants could stimulate fracture healing by active shortening and lengthening via SMA actuator wires; by emitting pulses, waves, or electromagnetic fields. However, it remains undefined which modes of application, forces, frequencies, force directions, time durations and periods, or other stimuli such implants should ideally deliver for the best result. The present paper reviews the literature on active implants and interventions for nonunion, discusses possible mechanisms of active implants and points out where further research and development are needed to build an active implant that applies the most ideal intervention

Single chain Fab (scFab) fragment

BACKGROUND: The connection of the variable part of the heavy chain (VH) and and the variable part of the light chain (VL) by a peptide linker to form a consecutive polypeptide chain (single chain antibody, scFv) was a breakthrough for the functional production of antibody fragments in Escherichia coli. Being double the size of fragment variable (Fv) fragments and requiring assembly of two independent polypeptide chains, functional Fab fragments are usually produced with significantly lower yields in E. coli. An antibody design combining stability and assay compatibility of the fragment antigen binding (Fab) with high level bacterial expression of single chain Fv fragments would be desirable. The desired antibody fragment should be both suitable for expression as soluble antibody in E. coli and antibody phage display. RESULTS: Here, we demonstrate that the introduction of a polypeptide linker between the fragment difficult (Fd) and the light chain (LC), resulting in the formation of a single chain Fab fragment (scFab), can lead to improved production of functional molecules. We tested the impact of various linker designs and modifications of the constant regions on both phage display efficiency and the yield of soluble antibody fragments. A scFab variant without cysteins (scFabΔC) connecting the constant part 1 of the heavy chain (CH1) and the constant part of the light chain (CL) were best suited for phage display and production of soluble antibody fragments. Beside the expression system E. coli, the new antibody format was also expressed in Pichia pastoris. Monovalent and divalent fragments (DiFabodies) as well as multimers were characterised. CONCLUSION: A new antibody design offers the generation of bivalent Fab derivates for antibody phage display and production of soluble antibody fragments. This antibody format is of particular value for high throughput proteome binder generation projects, due to the avidity effect and the possible use of common standard sera for detection