Asymmetric Synthesis of α‐Amino Acids under Operationally Convenient Conditions

A new multipurpose glycine equivalent for the general asymmetric synthesis of α‐amino acids is introduced. The chiral reagent can be transformed to various amino acids by alkylations with alkyl halides as well as aldol and Michael addition reactions under operationally convenient reaction conditions at room temperature with virtually complete stereochemical control.

     

Betriebliches Energiemanagement – Analysen, Methoden und Bewertungsmodelle zur Effizienzsteigerung

In recent years, the EU has been trying to increase political awareness of the energy problem. In 2007 and 2009, the first European energy strategy was adopted, the energy management standard EN 16001, which has been replaced by ISO 50001, was introduced in 2011. The introduction of an energy management standard in a company can contribute significantly to an increase of efficiency – already fixed in the Energy Efficiency Directive of the EU. The development of the Energy Pentagon – a model based on the decision-oriented business administration – allows individual industries to implement a customized holistic energy management. The model takes into account the three levels of management, namely the normative, strategic, and operational planning, and the five management functions, namely organization, personnel management, information, and control as well as the dynamic element of the development. The importance of enterprise energy management system is increasingly due to higher energy costs and a strong environmental awareness. In the future the focus should be increasingly on the implementation in SMEs and on a cost-effective analysis and evaluation of the efficiency gains particularly through the advancements in operational energy controlling.     

Dealcoholized red wine reverse vascular remodeling in an experimental model of metabolic syndrome: role of NAD(P)H oxidase and eNOS activity

The present study examines the effect of chronic administration of dealcoholized red wine Malbec (DRW) on vascular remodeling and NAD(P)H oxidase and endothelial nitric oxide synthase activity (eNOS) in an experimental model of metabolic syndrome induced by fructose administration. Thirty-day old male Wistar rats were fed a normal rat diet (control) or the same diet plus 10% fructose in drinking water (FFR). During the last 4 weeks of a 10-week period of the corresponding diet, a subgroup of control and FFR (n=8 each) received DRW in their drinking water. Systolic blood pressure (SBP), a homeostasis model assessment of insulin resistance (HOMA-IR), aortic NAD(P)H oxidase and eNOS activity in the heart and vascular tissue were evaluated. Vascular remodeling was evaluated in the left carotid artery (CA) and interlobar, arcuate and interlobular renal arteries (RA) through lumen to media (L/M) ratio determination. At the end of the study FFR increased the SBP (p < 0.001), HOMA-IR (p < 0.001), and aortic NAD(P)H oxidase activity (p < 0,05) but reduced cardiac and vascular eNOS activity (p < 0.01), L/M ratio in CA (p < 0.001) and RA (p < 0.01) compared with the C group. DRW reduced SBP (p < 0.05), aortic NAD(P)H oxidase (p < 0.05), and recovered eNOS activity (p < 0.001) and L/M in CA (p < 0.001) and RA (p < 0.001) compared with FFR. This study provides new data about the beneficial effect of DRW on oxidative stress and vascular remodeling in the experimental model of metabolic syndrome. Data suggest the participation of mechanisms involving oxidative stress in FFR alterations and the usefulness of natural antioxidant substances present in red wine in the reversion of these changes.     

Validation and application of an LC-MS/MS method for the determination of cyclic oligomers originating from polyamide 6 and polyamide 66 in food simulant

Polyamides (PAs) are used in the production of various food contact materials (FCMs) and articles such as kitchen utensils and packaging material. Cyclic oligomers have been identified as potential migrants from PA. This study describes the development, validation and application of a multi-oligomer analytical method based on LC-ESI-MS/MS for the identification and quantification of eight cyclic oligomers of PA 6 and four PA 66 migrating from FCMs into food simulant B (3% acetic acid) and beverages. It was proved that doubly charged precursor ions of the cyclic PA 6 and PA 66 oligomers above a mass of 500 Da are formed during the ionisation process of the electrospray technique used. Direct injection of a diluted food simulant into the LC-ESI-MS/MS system after migration makes the validated method a valuable tool for investigating migration of cyclic PA oligomers. The validation results demonstrate that the multi-oligomer method is applicable for the analysis of cyclic PA 6 and PA 66 oligomers in food simulant B. For all investigated cyclic PA oligomers, detection limits were in the range of 0.1–1.1 µg/l. Linearity (r² ≥ 0.99), trueness values between 91% and 122%, and intra-day (RSD_r < 10%) and inter-day precision (RSD_R < 19%) were determined and satisfied validation criteria set out by the European Reference Laboratory for FCMs. The method was extended to tap water and tea. Finally, the multi-oligomer method was successfully applied to determine cyclic PA oligomers in migration solutions originating from different PA FCMs. In all migration solutions, concentrations of cyclic PA oligomers were determined above the LOQ. A preliminary risk assessment based on in silico tools was performed. The results demonstrate the urgent need for toxicological data that would facilitate the evaluation of the health risk of cyclic PA oligomers.     

Calculation of the high-temperature strength of complexly alloyed nickel alloys using equations of the system of nonpolarized ionic radii

Modern complexly alloyed high-temperature nickel-base alloys contain up to 14 alloying elements. The complex composition ensures fulfillment of strict and often contradictory requirements imposed on the materials of critical parts of gas turbine engines (GTE). However, multi-component alloying creates considerable difficulties in the development of new compositions with specified characteristics or in the optimization of existing alloys. The present work is devoted to calculating the high-temperature strength of nickel alloys by means of the system of nonpolarized ionic radii (SNIR).Translated from Metallovedenie i Terrilicheskaya Obrabotka Metallov, No. 6, pp. 9–11, June, 1995.     

An experimental system for evaluation of well-defined catalysts on nonporous electrodes in realistic DMFC environment

This paper reports on an experimental setup wich enables us to investigate planar model catalysts in an environment closely resembling the environment found in an actual direct methanol fuel cell. The working electrodes were nano-structured catalyst particles immobilised on planar supports, reducing many of the commonly present non-catalyst related effects in conventional porous electrodes. Colloidal lithography was used for nano-structuring the samples. Nafion was used as electrolyte. Results are presented for the oxidation of methanol, formaldehyde, formic acid and carbon monoxide at temperatures between 30 and 70 ° C on Pt particles supported on glassy carbon disks.     

Comparison of histomorphometrical data obtained with two different image analysis methods

A common way to determine tissue acceptance of biomaterials is to perform histomorphometrical analysis on histologically stained sections from retrieved samples with surrounding tissue, using various methods. The “time and money consuming” methods and techniques used are often “in house standards”. We address light microscopic investigations of bone tissue reactions on un-decalcified cut and ground sections of threaded implants. In order to screen sections and generate results faster, the aim of this pilot project was to compare results generated with the in-house standard visual image analysis tool (i.e., quantifications and judgements done by the naked eye) with a custom made automatic image analysis program. The histomorphometrical bone area measurements revealed no significant differences between the methods but the results of the bony contacts varied significantly. The raw results were in relative agreement, i.e., the values from the two methods were proportional to each other: low bony contact values in the visual method corresponded to low values with the automatic method. With similar resolution images and further improvements of the automatic method this difference should become insignificant. A great advantage using the new automatic image analysis method is that it is time saving—analysis time can be significantly reduced.     

Methoden zum Einsatz diskreter,webbasierter Wetterprognosen in Gebäudetechnik und Lastmanagement

Using Discrete Online Weather Forecasts for Building Services Applications and Load Management. Usually, commercially used hourly weather forecasts of national weather institutes are implemented for predictive control strategies. Energy demand and energy loads are calculated by utilizing adequate models with predicted air temperatures. However, on the internet, numerous providers offer freely available weather forecasts. Mostly forecasts of maximum and minimum outside air temperatures are available for five to nine days in advance. Many applications in building services do require hourly or quarter‐hourly data. This paper describes a method for generating weather data of any resolution for freely available weather forecasts issued by online services. Ice storage and load prediction of a building are cited as examples of predictive control strategies using web‐based weather forecasts.