Quantisation Noise in Fixed-Point Multiplications

A new model to predict the quantization error after the multiplication of two quantized signals is presented. The proposed model is compared against a simplified model and a simple rule for the output wordlength is given. In addition the proposed model is applied to improve the signal-to-noise ratio (SNR) of accumulated multiplication results.     

Polymer Film Heat Transfer Surfaces in Seawater Desalination: Fouling Layer Formation and Technology

The emerging polyether ether ketone (PEEK) films were evaluated as future heat exchanger materials in seawater thermal desalination processes. Fouling resistance curves were measured in a pilot plant for pure PEEK films, talcum-filled PEEK films, and stainless-steel films with artificial seawater, showing that pure PEEK films have the advantage of weaker forces of adhesion or cohesion between the scaling materials and the film surface. Increasing the flow rate from 18 to 24 L min⁻¹ results in decreases of both the fouling rate and the asymptotic values. This was attributed to the lower polarity of 10.4 %, the lower arithmetic average roughness of 0.06 μm, and the homogeneous topography of the PEEK film. This polymer film is adaptable to in situ cleaning in thermal seawater desalination processes.     

Fusion of a recombinant antibody fragment with a homo-amino-acid polymer: effects on biophysical properties and prolonged plasma half-life

Chemical conjugation of small recombinant proteins with polyethylene glycol (PEG) is an established strategy to extend their typically short circulation times to a therapeutically useful range. We have investigated the production of a genetic fusion with a glycine-rich homo-amino-acid polymer (HAP) as an alternative way to attach a solvated random chain with large hydrodynamic volume. The anti-HER2 Fab fragment 4D5 was used as a model system and fused with either 100 or 200 residue polymers of the repetitive sequence (Gly(4)Ser)(n) to its light chain. Both fusion proteins were successfully produced in the periplasm of Escherichia coli and obtained as homogeneous preparations after two-step affinity chromatography via the His(6) tag fused to the heavy chain and the Strep-tag II fused to the extended light chain. Both modified Fab fragments showed binding activity towards the HER2 antigen indistinguishable from the conventional recombinant Fab fragment. When compared with the unfused Fab fragment, a significantly increased hydrodynamic volume, by ca. 120%, was observed during gel filtration for the 200 residue HAP fusion protein and, to a lesser extent, in the case of the 100 residue HAP. Difference CD measurements revealed a characteristic random coil spectrum for the 100 and 200 residue HAP fusion moieties. Finally, pharmacokinetic experiments were carried out in mice after radioiodination of the recombinant Fab fragments. Although the 100 residue HAP fusion showed a behavior very similar to the unfused Fab fragment, with a terminal plasma half-life of ca. 2 h, the 200 residue HAPylated Fab fragment gave rise to a significantly prolonged half-life of ca. 6 h. While this moderate effect may so far be most beneficial for specialized medical applications, such as in vivo imaging, the genetic engineering of optimized HAP sequences should yield pharmacokinetic properties similar to PEGylation, yet without necessitating in vitro modification steps.     

Tripodal polyamines: Adjustable receptors for cation extraction

ABSTRACT

Extraction experiments of a series of tris(2-aminoethyl)amine-based ligands with different aromatic substituents act as efficient extractants for transition metals. Octanol-water distribution measurements, determined stability constants of Ag(I) complexes and Zn(II) extraction studies with different counterions point to the extraction efficiency in dependence of the ligand lipophilicity and the specific structure of the ligand. Competitive extraction experiments showed a selective extraction of Cu(II) from a mixture of Co(II), Ni(II), Cu(II), Zn(II), and Cd(II). Additional hydroxyl groups in (tris(2-hydroxybenzylaminoethyl)amine lead to a loss of this selectivity with extraction yields of 46%, 86% and 97% for Co(II), Ni(II) and Cd(II) ions.     

Entrainment Control Using a Newly Developed Telecentric Inline Probe

This contribution presents a novel approach to investigate entrainment in distillation and absorption columns. An image-based probe allows precise droplet detection at various radial and axial positions above trays. Validations achieve an average error of 6.4 % (monospheres 9.2–114.4 µm) and 3 % (monodisperse droplet stream up to 19 m s⁻¹ and 74.5 µm). Experiments in a DN 450 cold flow test rig show an increasing (decreasing) share of larger droplets with higher gas (liquid) loads. Locally measured droplet sizes depend on probe position as well as tray design and enable an extrapolation to integral entrainment rates.     

Hypothyroidism Exacerbates Thrombophilia in Female Rats Fed with a High Fat Diet

Clotting abnormalities are discussed both in the context with thyroid dysfunctions and obesity caused by a high fat diet. This study aimed to investigate the impact of hypo-, or hyperthyroidism on the endogenous thrombin potential (ETP), a master indicator of clotting activation, on Sprague Dawley rats fed a normal or high fat diet. Female Sprague Dawley rats (n = 66) were grouped into normal diet (ND; n = 30) and high-fat diet (HFD; n = 36) groups and subdivided into controls, hypothyroid and hyperthyroid groups, induced through propylthiouracil or triiodothyronine (T3) treatment, respectively. After 12 weeks of treatment ETP, body weight and food intake were analyzed. Successfully induced thyroid dysfunction was shown by T3 levels, both under normal and high fat diet. Thyroid dysfunction was accompanied by changes in calorie intake and body weight. In detail, compared to euthyroid controls, hypothyroid rats showed significantly increased—and hyperthyroid animals significantly decreased—ETP levels. High fat diet potentiated these effects in both directions. In summary, we are the first to show that hypothyroidism and high fat diet potentiate the thrombotic capacity of the clotting system in Sprague Dawley rats. This effect may be relevant for cardiovascular disease where thyroid function is poorly understood as a pathological contributor in the context of clotting activity and obesogenic nutrition.     

Oxidized LDL Is Strictly Limited to Hyperthyroidism Irrespective of Fat Feeding in Female Sprague Dawley Rats

Metabolic dysfunctions might play a crucial role in the pathophysiology of thyroid dysfunctions. This study aimed to investigate the impact of a controlled diet (normal versus high fat feeding) on hypothyroid and hyperthyroid Sprague Dawley rats. Female Sprague Dawley rats (n = 66) were grouped into normal diet (n = 30) and high-fat diet (n = 36) groups and subdivided into controls, hypothyroid and hyperthyroid groups, induced through propylthiouracil or triiodothyronine (T3) treatment, respectively. After 12 weeks of treatment metabolic parameters, such as oxidized LDL (oxLDL), malondialdehyde (MDA), 4-hydroxynonenal (HNE), the lipid profile, body weight and food intake parameters were analyzed. Successfully induced thyroid dysfunctions were shown by T3 levels, both under normal and high fat diet. Thyroid dysfunctions were accompanied by changes in calorie intake and body weight as well as in the lipid profile. In detail, hypothyroid rats showed significantly decreased oxLDL levels, whereas hyperthyroid rats showed significantly increased oxLDL levels. These effects were seen under high fat diet and were less pronounced with normal feeding. Taken together, we showed for the first time in female SD rats that only hyper-, but not hypothyroidism, is associated with high atherogenic oxidized LDL irrespective of normal or high-fat diet in Sprague Dawley rats.     

Separation Units 4.0 – Trenntechnik in der chemischen Industrie auf dem Weg in die digitale Zukunft. Eindrücke und erste Ergebnisse vom Tutzing-Symposion 2019

In October 2019 the ProcessNet Section „Fluid Dynamics and Separation” invited experts from academia and industry to discuss the status and future developments in the field. In contrast to earlier events considering a whole plant the focus was complementary on apparatus level. In five clusters within several workshops decision makers evaluated opportunities, challenges, and further cross-linking with other branches as a basis for further activities such as white paper, roadmap, etc.     

Metallopolymer Organohydrogels with Photo-Controlled Coordination Crosslinks Work Properly Below 0 °C

Controlling the structures and functions of gels is important for both fundamental research and technological applications. Introducing photoresponsive units into gels enables remote control of their properties with light. However, existing gels show photoresponsiveness only at room temperature or elevated temperatures. The development of photoresponsive gels that work below 0 °C can expand their usage in cold environments. Here, photoresponsive metallopolymer organohydrogels that function even at −20 °C are reported. The organohydrogels are prepared using photoresponsive Ru–thioether coordination bonds as reversible crosslinks to form polymer networks. A water/glycerol mixture is used as an anti-freezing solvent. At −20 °C, the Ru–thioether coordination bonds are dissociated under light irradiation and reformed reversibly in the dark, which result in alternating crosslinking densities in the polymer networks. This process enables inducing reversible gel-to-sol transitions, healing damaged gels, controlling the mechanical properties and volumes of the gels, and rewriting microstructures on the gels below 0 °C.