Flavonoid concentrations in the inner leaves of head lettuce genotypes

Typical HPLC profiles of phenolics from head lettuce (butter lettuce) genotypes showed quercetin (Qu) compounds Qu 3-O-glucuronide, Qu 3-O-(6-malonylglucoside), an acidic luteolin (Lu) glycoside, chlorogenic acid and chicoric acid as the main compounds in outer and - except the Lu conjugate - inner leaves.The outer leaves of some genotypes additionally contained cyanidin 3-O-(6-malonylglucoside). The generally marginal flavonoid concentrations of the cores of lettuce heads increased between 10-fold and 20-fold during the illumination of opened inner leaves. This indicated the competence of inner leaves of lettuce heads to perform the light-dependent flavonoid biosynthesis. After hydrolysis of flavonoid extracts from 15 head lettuce varieties, Qu concentrations were detected between 19.4 and 152.1 µg/g dry plant material (DW) in inner leaves and from 417.3 to 2482.7 µg/g DW in outer leaves. While the Qu concentrations of the inner leaves of most genotypes, including the commercial varieties, amounted to about 3% of those found in outer leaves, these proportions were 15% and 19% in two genotypes. Two other varieties showed relatively high Qu values of cores in connection with maximum flavonoid levels of outer leaves. It is indicated that such genotypes may be useful in increasing the flavonoid concentrations in the inner leaves of commercial head lettuce varieties by conventional breeding methods.     

Reaktionen mit Cyclobutendionen. LIII [1]. Neue heterocyclische Systeme durch Umsetzung von 4-[-(z)-Benzyliden]-2,3-diphenyl-cyclobut-2-enon mit Diazomethan

Reaction of Cyclobutendiones. LIII. New Heterocyclic Systems by Reaction of 4-[-(z)-Benzylidenene]-2,3-diphenyl-cyclobut-2-enone with Diazomethane The addition of diazomethane to stable 4-alkylidene-cyclobut-2-enones gives at the same time the 1:1 adducts 2 , and under elimination of 1 mole nitrogene the 1:2 adducts 3 respectively the 1:3 adducts 4 .     

Hydration-Induced Void-Containing Hydrogels for Encapsulation and Sustained Release of Small Hydrophilic Molecules

Efficient encapsulation and sustained release of small hydrophilic molecules from traditional hydrogel systems are challenging due to the large mesh size of 3D networks and high water content. Furthermore, the encapsulated molecules are prone to early release from the hydrogel prior to use, resulting in a short shelf life of the formulation. Here, a hydration-induced void-containing hydrogel (HVH) based on hyperbranched polyglycerol-poly(propylene oxide)-hyperbranched polyglycerol (HPG-PPG-HPG) as a robust and efficient delivery system is presented for small hydrophilic molecules. Specifically, after the HPG-PPG-HPG is incubated overnight at 4 °C in the drug solution, it is hydrated into a hydrogel containing micron-sized voids, which can encapsulate hydrophilic drugs and achieve 100% drug encapsulation efficiency. In addition, the voids are surrounded by a densely packed polymer matrix, which restricts drug transport to achieve sustained drug release. The hydrogel/drug formulation can be stored for several months without changing the drug encapsulation and release properties. HVH hydrogels are injectable due to shear thinning properties. In rats, a single injection of the HPG-PPG-HPG hydrogel containing 8 µg of tetrodotoxin (TTX) produces sciatic nerve block lasting up to 10 h without any TTX-related systemic toxicity nor local toxicity to nerves and muscles.     

Modeling melt conveying and power consumption of co-rotating twin-screw extruder kneading blocks: Part B. Prediction models

Intermeshing co-rotating twin-screw extruders are very versatile because their screw configurations can be tailored both to the application and to the properties of the materials used. Finding the best screw configuration is one of the main purposes of twin-screw extrusion modeling, and requires models that accurately predict conveying and power consumption. The better the process can be predicted, the better the requirements of the final product can be met. We present novel prediction models of the conveying and power-consumption behaviors of intermeshing co-rotating twin-screw extruder kneading blocks for Newtonian fluids. These are based on numerical simulations and therefore consider the complex three dimensional (3D) geometry of this element type without the need for common simplifications. Our models are thus capable of including all leakage flows and gap influences, which are usually ignored, for example, by the flat-plate model. Since our models are derived by symbolic regression based on genetic programming, they consist of algebraic functions and are low-threshold. They can be used to calculate various process parameters for individual kneading blocks or entire screw configurations, as illustrated by a use case.     

A Bioengineering-Regenerative Medicine Approach for Ocular Surface Reconstruction Using a Functionalized Native Cornea-Derived Bio-Scaffold

Limbal stem cell deficiency (LSCD) is characterized by the loss of limbal epithelial stem cells (LESCs) which compromises corneal transparency, leading to blindness. It cannot be treated with pharmacological or corneal transplantation interventions, instead a specialized stem cell (SC) therapy is needed to restore eye health and sight. Herein, a native cornea-derived biomaterial, a by-product of a laser refractive surgical procedure called small incision lenticule extraction is identified as a new cell delivery matrix. Culture conditions are optimized to facilitate LESC attachment, expansion and stratification, and their identity is immunophenotyped. Using electron microscopy, bio-constructs display stratification, similar to the architectural and cellular organization of a native mammalian cornea with formation of a basement membrane and an orderly array of collagen fibrils. Neuronal growth and depleted CD45⁺/CD14⁺ leukocytes on lenticules are also shown, suggesting that in transplantation experiments, they will re-innervate and not trigger a host-mediated immune response. Finally, human lenticules are geometrically customized to successfully fit them over a LSCD murine cornea ex vivo, during which they maintain curvature. The authors are poised to conduced similar studies in live mice using these and other carriers currently used in the clinic to compare SC therapy outcomes.     

Zur Beurteilung des Ankündigungsverhaltens von Spannbetonbrücken nach dem Riss‐vor‐Bruch‐Kriterium. Vorschläge zur Vorgehensweise bei gefährdeten Brücken

Interpretation of the Preannouncement Behaviour of Prestressed Concrete Bridges by applying the “Crack‐before‐Collapse‐Criterion” Proposals for further Proceeding with Critical Bridges Due to extending lifetimes of prestressed concrete bridges the importance of the durability increases. With numerical calculations and investigations of structures according to DIN 1076 it is intended to recognize and prevent possible failure of the structures in time and to minimize the risk for the owner during the remaining lifetime. Especially older prestressed concrete bridges with tension wires endangered to stress‐corrosion‐cracking need to be numerically investigated and judged concerning their preannouncement behaviour according to the “crack‐before‐collapse‐criterion”. According to the numerical results of the “crack‐before‐collapse‐criterion” and supplemental calculations it is possible to evaluate the existing risk for the owner concerning failure of the structures. The design of the concerned structures will be discussed. Based on results of performed investigations proposals for further proceeding with older critical bridges will be given along with recommendations how to limit the remaining risks. For newer bridges the analysis according to the “crack‐before‐collapse‐criterion” is a measure of a sufficient sturdiness.     

Non‐Racemic Halohydrins via Biocatalytic Hydrogen‐Transfer Reduction of Halo‐Ketones and One‐Pot Cascade Reaction to Enantiopure Epoxides

Biocatalytic hydrogen‐transfer reduction of α‐chloro‐ketones furnished non‐racemic chlorohydrins by employing either Rhodococcus ruber as lyophilized cell catalyst or an alcohol dehydrogenase preparation from Pseudomonas fluorescens DSM 50106 (PF‐ADH). For all substrates investigated, Rhodococcus ruber gave strictly the “Prelog” product, whereas PF‐ADH showed scattered stereopreference. One possibility for a follow‐up reaction of halohydrins is the ring closure to the corresponding epoxide. A novel “one pot‐one step strategy” was employed to obtain the enantiopure epoxide from the α‐chloro‐ketone in a cascade like fashion at pH>12 involving biocatalytic hydrogen transfer reduction and in situ chemo‐catalyzed ring closure.