Selective Functionalization of Microstructured Surfaces by Laser‐Assisted Particle Transfer

Microcavity arrays represent millions of different reaction compartments to screen, for example, molecular interactions, exogenous factors for cells or enzymatic activity. A novel method is presented to selectively synthesize different compounds in arrays of microcavities with up to 1 000 000 cavities per cm². In this approach, polymer microparticles with embedded pre‐activated monomers are selectively transferred into microcavities with laser radiation. After particle patterning, heating of the particle matrix simultaneously leads to diffusion and coupling of the monomers inside each microcavity separately. This method exhibits flexibility, not only in the choice of compounds, but also in the choice of particle matrix material, which determines the chemical reaction environment. The laser‐assisted selective functionalization of microcavities can be easily combined with the intensively growing number of laser applications for patterning of molecules and cells, which is useful for the development of novel biological assays.     

Analytical study of apple liqueurs

In the present work the composition of apple liqueurs has been analysed, since the consumption of these beverages in Spain has increased during the last years. Twenty-five samples, belonging to the most representative five brands of the Spanish market have been analysed. The following determinations were carried out: alcoholic grade, total acidity, methanol, furfurol, dry extract, reducing sugars, sucrose, ash contact, macroelements (Na, K, Ca, Mg) and microelements (Cu, Fe, Mn, Zn). These parameters enable the quality evaluation of these beverages and contribute to their characterization with respect to the fruit used in their elaboration. To complete the experimental study, a BMDP 7M discriminant statistical analysis has been applied to the results obtained. The variables that best discriminate the groups have been determined and all the samples have been classified and differentiated.

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Analytisches Studium der Apfelsaftliköre

Zusammenfassung Es wurde die Zusammensetzung von Apfelsaftlikören analysiert, weil diese Getränke öfter in Spanien getrunken werden. Fünfundzwanzig Proben von fünf bestimmten, spanischen Markengetränken wurden analysiert. Es wurden folgende Bestimmungen ausgeführt: Alkoholkonzentration, Gehalt an Säure, Methanol, Extrakt, Zucker, Sucrose, Asche, Macroelemente (Na, K, Ca, Mg) und Mikroelemente (Cu, Fe, Mn, Zn). Diese Parameter erlauben die Qualität dieser Getränke zu schätzen und ihre Charakterisierung auf Grund des Fruchtgehaltes. Weiterhin wurde eine BMDP 7M diskriminant-statistische Analyse der Resultate angewandt. Die diskriminant-Variablen der Gruppe wurden bestimmt und alle Proben konnten klassifiziert und unterschieden werden.

     

Debonding analysis of thin plates from curved substrates

This paper is focused on the analytical modeling of the interface between a rigid substrate with constant curvature and a thin bonded plate. In a previous investigation, an analytical cohesive zone (CZ) model capable of predicting the interfacial behavior prior to the onset of debonding has been proposed by the authors. As a follow-up, this paper presents a new analytical model, which is able to predict both the load at onset of debonding and the subsequent evolution of the debonding process. The study clarifies the essential differences in behavior between joints with flat and curved substrates during debonding. The new analytical model is based on linear-elastic fracture mechanics (LEFM) and is developed under two distinct assumptions: a mode-independent fracture energy, and a fracture energy dependent on the mode mixity, according to a simple mixed-mode fracture criterion. The model is applied to the determination of the load at onset of debonding, and to the prediction of the load-displacement behavior during the entire debonding process. The relationship between the predictions of the CZ and LEFM models regarding the load at initiation of debonding is also established.     

Combined Nano‐ and Micro‐Scale Topographic Cues for Engineered Vascular Constructs by Electrospinning and Imprinted Micro‐Patterns

The major cause of synthetic vessel failure is thrombus and neointima formation. To prevent these problems the creation of a continuous and elongated endothelium inside lumen vascular grafts might be a promising solution for tissue engineering. Different micro‐ and nano‐surface topographic cues including grooved micro‐patterns and electrospun fibers have been previously demonstrated to guide the uniform alignment of endothelial cells (ECs). Here, with a very simple and highly versatile approach we combined electrospinning with soft lithography to fabricate nanofibrous scaffolds with oriented fibers modulated by different micro‐grooved topographies. The effect of these scaffolds on the behavior of the ECs are analyzed, including their elongation, spreading, proliferation, and functioning using unpatterned random and aligned nanofibers (NFs) as controls. It is demonstrated that both aligned NFs and micro‐patterns effectively influence the cellular response, and that a proper combination of topographic parameters, exploiting the synergistic effects of micro‐scale and sub‐micrometer features, can promote EC elongation, allowing the creation of a confluent ECs monolayer in analogy with the natural endothelium as assessed by the positive expression of vinculin. Combining different micro‐ and nano‐topographic cues by complementary soft patterning and spinning technologies could open interesting perspectives for engineered vascular replacement constructions.     

Highly efficient enzyme-functionalized porous zirconia microtubes for bacteria filtration

In contrast to polymer membranes, ceramic membranes offer considerable advantages for safe drinking water provision due to their excellent chemical, thermal, and mechanical endurance. In this study, porous ceramic microtubes made of yttria stabilized zirconia (YSZ) are presented, which are conditioned for bacteria filtration by immobilizing lysozyme as an antibacterial enzyme. In accordance with determined membrane pore sizes of the nonfunctionalized microtube of ≤200 nm, log reduction values (LRV) of nearly 3 (i.e., bacterial retention of 99.9%) were obtained for bacterial retention studies using gram-positive model bacterium Micrococcus luteus. Immobilization studies of lysozyme on the membrane surface reveal an up to six times higher lysozyme loading for the covalent immobilization route as compared to unspecific immobilization. Antibacterial activity of lysozyme-functionalized microtubes was assessed by qualitative agar plate test using Micrococcus luteus as substrate showing that both the unspecific and the covalent lysozyme immobilization enhance the microtubes' antibacterial properties. Quantification of the enzyme activity at flow conditions by photometric assays reveals that the enzyme activities of lysozyme-functionalized microtubes depend strongly on applied flow rates. Intracapillary feeding of bacteria solution and higher flow rates lead to reduced enzyme activities. In consideration of different applied flow rates in the range of 0.2-0.5 mL/min, the total lysozyme activity increases by a factor of 2 for the covalent immobilization route as compared to the unspecific binding. Lysozyme leaching experiments at flow conditions for 1 h show a significant higher amount of washed-out lysozyme (factor 1.7-3.4) for the unspecific immobilization route when compared to the covalent route where the initial level of antibacterial effectiveness could be achieved by reimmobilization with lysozyme. The presented platform is highly promising for sustainable bacteria filtration.     

Fungal resistance and physical–mechanical properties of beech plywood having durable veneers or fungicides in surfaces

Improvement of insufficient fungal resistance of beech plywood for wet conditions was examined by: (1) incorporation of durable oak (Quercus robur) or black locust (Robinia pseudoacacia) surface veneers instead of beech (Fagus sylvatica) ones; (2) primordial treatment of beech surface veneers with 0.5, 1, 1.5 and 3 % solutions of fungicides DDAC, IPBC, Propiconazole and Tebuconazole; (3) additional treatment of beech plywood with the same fungicides. The anti-fungal efficiency of these three methods, applied to five-layer plywood boards glued with phenolic resin, was assessed either by decay test with two brown rot fungi (Coniophora puteana and Serpula lacrymans) and one white rot fungus (Trametes versicolor) using edge protected specimens according to modified ENV 12038, or by mould test with two microscopic fungi (Aspergillus niger and Penicillium brevi-compactum) according to modified EN 15457. The durability of beech plywood significantly increased after incorporation of black locust veneers into the surface layers, and also thanks to organic fungicides (0.5 % IPBC, Propiconazole or Tebuconazole, and 1.5 % DDAC) present in the surfaces. Other selected properties of beech plywood were sometimes influenced positively (e.g., soaking due to less permeable black locust and oak surface veneers) or negatively (e.g., shear strength due to fungicides).     

The anticarcinogenic potential of essential oil and aqueous infusion from caper (Capparis spinosa L.)

The present study assessed the influence of essential oil and aqueous infusion from wild-grown caper (Capparis spinosa L.) on cell growth, NF-κB activation, apoptosis and cell cycle in the human colon carcinoma cell line, HT-29. Methyl isothiocyanate (92.06%), a degradation product of glucosinolate glucocapparin, was detected as major component of essential oil from caper leaves and flower buds. Aqueous infusion of caper showed an interesting and variegate compositional pattern containing several phenolic compounds, among which a flavonol glycoside, rutin (quercetin 3-O-rutinoside, 50.7%) and 5-caffeoyl-quinic acid (chlorogenic acid, 17.5%) were detected as dominant. Caper essential oil and aqueous infusion showed time- and dose-dependent high inhibitory effect on HT-29 cell proliferation. In addition, they induced the inhibition on nuclear factor κB (NF-κB) activity in a dose-dependent manner, while they did not show any effect on apoptosis in HT-29 cells. Flow cytometric analysis indicated that treatment with caper essential oil and aqueous infusion resulted in G₂/M cell cycle arrest in a dose-dependent manner. Presented results suggest that caper contains volatile and non-volatile compounds which potentially can play an important role in colon cancer prevention.     

Wood surface discolouration due to simulated indoor sunlight exposure

Wood surface colour is a very important quality criterion in the utilisation of wood, especially in indoor applications. In this study, an attempt was made to analyse wood surface discolouration due to artificial indoor light irradiation of the most frequently traded wood species in Europe altogether. Sixteen wood species, twelve hardwood and four softwood species, were exposed for 120 hours to a xenon-arc lamp equipped with a 3 mm window glass filter, in order to simulate natural sunlight behind a window glass. Eleven wood species were chosen and further exposed to irradiation for up to 600 hours. Colour measurements were performed by means of a colorimeter device on exposed and non-exposed areas of the samples. Using the CIE-L*a*b* colour measuring system, wood surface discolouration was measured and calculated according to ?L*, ?a*, ?b* and ?E* values. An idea of the different behaviour of these species and how they relate to each other could be given.     

Protective effect of fresh and processed Jalapeño and Serrano peppers against food lipid and human LDL cholesterol oxidation

The potential of fresh and processed Jalapeño and Serrano pepper extracts for the control of lipid oxidation in several systems was investigated. The assays used included β-carotene/linoleate model system, striped corn oil, ground pork meat and Cu(II)-induced oxidation of human low-density lipoprotein (LDL). The results showed that all extracts were effective in at least one system, although their potency varied. Extracts of smoked Jalapeño were particularly effective. The lipid-protective effect of the extracts was mainly due to the presence of phenolic compounds, but other phytochemicals, such as chlorophylls were also involved.