On reduced modeling of mass transport in wavy falling films

In many industrial units such as packing columns, falling film reactors, etc., the liquid phase is designed as a falling film. It is well known that the mass and heat transfer in laminar wavy film flows is significantly enhanced compared to flat films. The kinetic phenomena underlying the increase in mass and heat transfer are, however, still not fully understood. For an efficient design of falling film units, computational models that account for these enhanced transport mechanisms are of key importance. In this article, we present a reduced modeling approach based on a long‐wave approximation to the fluid dynamics of the film. Furthermore, we introduce a new two‐dimensional (2D) high‐resolution laser‐induced luminescence measurement technique. Both in the numerical simulation results and in the high‐resolution 2D‐concentration measurements obtained in the experiments we observe similar patterns of high concentrations locally, especially in the areas close to the wave hump. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2265–2276, 2018     

Absolute Configuration of β- and α-Asymmetric Carbons within β-O-4-Structures in Hardwood Lignin

In this study, we investigated the proportion of erythro- and threo-forms of β-O-4-ether structures and their enantiomeric compositions in hardwood lignin by applying the ozonation method to birch wood meal. Optical activity was not substantially observed in either the erythronic or threonic acids obtained as the ozonation products of β-O-4-structures in birch wood meal. The proportions of the four stereoisomeric forms {(αS,βR)-erythro, (αR,βR)-threo, (αS,βS)-threo, and (αR,βS)-erythro forms} were estimated to be 37-38%, 13-14%, 12-13%, and 36-37% based on the yields of erythronic and threonic acids, and on their optical activities. The proportions suggest that the entire components of β-O-4-ether structures in birch wood lignin have R- and S-configurations at the β-carbon in approximately the same quantities {(βR)-β-O-4-structure: (βS)-β-O-4-structure = 50–52:48–50}; i.e., that the β-ether structures are essentially racemic. This estimation implies that, during lignin biosynthesis, an equal number of enantiomeric forms of β-O-4-bonded quinone methides were formed by radical coupling reactions.     

Nuclear magnetic resonance characterization of high- and ultrahigh-performance concrete: Application to the study of water leaching

In the present study, we show that high-resolution ²⁹Si and ²⁷Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) can be a powerful tool for analyzing actual concrete mixes. The influence of the amount of silica fume and of the type of cement in high-performance concrete (HPC), as well as the influence of the type of silica fume and of the granular packing in ultrahigh-performance concrete (UHPC) were investigated. Significant effects on the amount and shape of C-S-H, on the incorporation of aluminum in the C-S-H structure, and on the distribution of aluminum-containing hydrates were observed. Nuclear magnetic relaxation of protons was also performed and it showed the fractal feature of the pore size distribution in UHPC and the higher amount of larger pores in HPC. The microstructure of the surface of these same formulations leached by mineral water for up to 1 year exhibits slight modifications.     

Single-stage flowing liquid film impactor for continuous on-line particle analysis

A single-stage “wet impactor” is presented, where the impaction occurs on a regenerated water surface. The developed impactor is equipped with an impaction liquid support plate of etched glass and a drain spout providing a continuous liquid flow covering the impaction area. Subsequent transport of the impaction liquid makes an on-line determination possible. With multiple nozzles (74 holes, 0.3 mm i.d.) and an air flow of 101/min the cut-off was determined to 0.41 ± 0.02 μm. The impactor was also investigated for its particle loss. The cut-off function, regarding the consequences of letting impaction occur in a liquid film is discussed and compared to conventional impactors. The analysis technique was tested in an ambient air measurement study with an ion chromatograph attached to the sampling system.     

A novel type of equipment for reactive distillation: Model development,simulation, sensitivity and error analysis

A simulation study of heterogeneously catalyzed reactive distillation experiments carried out with the D + R tray, a novel type of laboratory equipment, is presented. One advantage of the D + R tray is that reaction and distillation are alternating stage‐wise, in a well‐defined way that can be modeled straightforwardly. An equilibrium stage model is used to describe the distillation and a plug flow reactor model to describe the catalyst bed reactors. The model parameters are derived from a systematic experimental characterization of the D + R tray both as a reactor and as a distillation unit. A validated physicochemical fluid property model is used. The primary experimental data are reconciled. Results from the predictive simulations are in good agreement with the experimental results. The influence of errors in the input parameters on the simulation results is investigated by means of a sensitivity and error analysis. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1533–1543, 2013     

Integrative Analysis of Metabolomic,Proteomic and Genomic Data to Reveal Functional Pathways and Candidate Genes for Drip Loss in Pigs

The aim of this study was to integrate multi omics data to characterize underlying functional pathways and candidate genes for drip loss in pigs. The consideration of different omics levels allows elucidating the black box of phenotype expression. Metabolite and protein profiling was applied in Musculus longissimus dorsi samples of 97 Duroc × Pietrain pigs. In total, 126 and 35 annotated metabolites and proteins were quantified, respectively. In addition, all animals were genotyped with the porcine 60 k Illumina beadchip. An enrichment analysis resulted in 10 pathways, amongst others, sphingolipid metabolism and glycolysis/gluconeogenesis, with significant influence on drip loss. Drip loss and 22 metabolic components were analyzed as intermediate phenotypes within a genome-wide association study (GWAS). We detected significantly associated genetic markers and candidate genes for drip loss and for most of the metabolic components. On chromosome 18, a region with promising candidate genes was identified based on SNPs associated with drip loss, the protein “phosphoglycerate mutase 2” and the metabolite glycine. We hypothesize that association studies based on intermediate phenotypes are able to provide comprehensive insights in the genetic variation of genes directly involved in the metabolism of performance traits. In this way, the analyses contribute to identify reliable candidate genes.     

Spezifische Bedarfe bei zahnärztlichen Patienten mit Demenz und ihre ethischen Implikationen

Definition of the problem

The central foundations of successful dental treatment consist of a trustful patient-dentist relationship, the professional and psychosocial expertise of the team treating the patient, and consideration of ethical aspects both during the therapeutic decision-making process and during the subsequent execution of therapy. This is especially true of the dental treatment of (mostly elder) persons with dementia, calling for an in-depth assessment of the various normative implications.

Arguments

In geriatric dentistry in particular, situational dilemmas regarding treatment often arise from specific constellations (e.?g. greatly reduced potential for dental therapy, lack of ability regarding oral hygiene and lack of individual patient responsibility) combined with an acute need for treatment and the necessary involvement of third parties. These dilemmas frequently place additional professional and normative demands on the dentist. The current contribution discusses this specific situation, first by way of theoretical discourse and subsequently with a case-related approach on the basis of two case histories.

Conclusion

It becomes clear here that classic state-of-the-art therapies are replaced by “compromise treatment” in many cases in geriatric dentistry. Such treatment follows divergent diagnostic and therapeutic rules, poses changed requirements in terms of communication and presents specific ethical challenges and pitfalls.

     

AlMnFeSi合金退火过程中的微观组织及力学性能的演变

通过2种不同的均匀化热处理及随后的冷轧,使一种3xxx系模型合金获得不同尺寸和分布的弥散析出相,并使铝基体含有不同含量的Mn。系统研究不同均匀化热处理组织和冷轧变形量对退火过程中模型合金的回复与再结晶行为的影响。根据实验结果,绘制出弥散析出相和再结晶过程的相互作用时间-温度-转变曲线（TTT）。TTT曲线显示固溶体中Mn的含量和弥散析出相的颗粒密度对软化行为有强烈的影响。在再结晶退火过程中或再结晶退火之前析出的高密度、细小、弥散析出相显著阻碍软化过程,并形成粗大的再结晶组织。在没有细小、稠密的弥散相影响下的再结晶退火,可以获得均匀、细小的等轴晶。而且,弥散析出相对再结晶过程的阻碍作用取决于再结晶过程的持续时间和弥散析出相的数量。在持续时间长的再结晶过程中,细小、稠密的弥散相对再结晶有着强烈的影响,而在其他情况下影响则有限。不管再结晶过程中是否受到弥散相析出的影响,在再结晶退火之前已经存在于组织中的细小、稠密的弥散相（平均尺寸0.1μm）也会导致再结晶退火之后形成粗大的再结晶组织。     

Increased in vitro Anti-HIV Activity of Caffeinium-Functionalized Polyoxometalates

Polyoxometalates (POMs), molecular metal oxide anions, are inorganic clusters with promising antiviral activity. Herein we report increased anti-HIV-1 activity of a POM when electrostatically combined with organic counter-cations. To this end, Keggin-type cerium tungstate POMs have been combined with organic methyl-caffeinium (Caf) cations, and their cytotoxicity, antiviral activity and mode of action have been studied. The novel compound, Caf₄K[β₂-CeSiW₁₁O₃₉]×H₂O, exhibits sub-nanomolar antiviral activity and inhibits HIV-1 infectivity by acting on an early step of the viral infection cycle. This work demonstrates that combination of POM anions and organic bioactive cations can be a powerful new strategy to increase antiviral activity of these inorganic compounds.     

Mediator-Related Symptoms and Anaphylaxis in Children with Mastocytosis

Mastocytosis is characterized by the pathological accumulation of mast cells (MC) in various organs. In these patients, MC may degranulate and thereby contribute to clinical symptoms, especially when a concomitant allergy is present. However, MC activation can not only be induced by high-affinity receptors for IgE, but also by anaphylatoxins, neuropeptides, IgG immune complexes, complement-components, drugs, products of bacteria or parasites, as well as physical factors such as heat, cold, vibration, stress, sun, or physical effort. Symptoms due to mediators released by activated MC may develop in adults suffering from systemic mastocytosis, but also evolve in children who usually have cutaneous mastocytosis (CM). Clinically, CM is otherwise characterized by typical brown, maculopapular skin lesions or mastocytoma associated with a positive Darier’s sign. Pruritus and flushing are common and blistering may also be recorded, especially in diffuse CM (DCM). Pediatric patients with mastocytosis may also have gastrointestinal, respiratory, and neurologic complaints. Although anaphylaxis is not a typical finding, pediatric patients with massive skin involvement and high tryptase levels have a relatively high risk to develop anaphylaxis. This paper reviews MC mediator-related symptoms and anaphylaxis in children with mastocytosis, with special emphasis on risk factors, triggers, and management.