Application of magnetic polymethacrylate‐based microspheres for the isolation of DNA from raw vegetables and processed foods of plant origin

A method for the microextraction of DNA from raw vegetables and highly processed foods of plant origin suitable for PCR analysis was developed. It is based on non‐selective binding of DNA in the presence of PEG 6,000/NaCl to hydrophilic magnetic nonporous poly(2‐hydroxyethyl methacrylate‐co‐glycidyl methacrylate) ‐ P(HEMA‐co‐GMA) microspheres covered by carboxyl groups. The quantitative polymerase chain reaction (qPCR) by in‐house designed primers targeting a highly repetitive rDNA locus allowed for detection of plant DNAs in a wide range of concentrations (0.1 pg/μL to 10 ng/μL). The described procedure is fast and simple. We further demonstrate that relatively mild acidic treatment of vegetable at elevated temperatures resulted in a dramatic reduction of PCR efficiency indicating extensive degradation of DNA during pickling. The described method is suitable for the analysis of highly degraded DNA from pickled food products.

Practical applications

DNA‐based methods, such as the polymerase chain reaction (PCR), represent an important genetic approach for identification of plant species composition of foods. DNA from processed foods varies in both quality and quantity between the protocols used. Plant samples are generally characterised by a complex composition containing various inhibitors of PCR. Current methods have been tailored for specific samples while no universal protocol is available. Development of a simple universal procedure leading to PCR‐ready DNA would be beneficial. Isolation strategies based on solid phase systems have become popular for PCR‐ready DNA isolations from complex matrices. Here we applied magnetic hydrophilic P(HEMA‐co‐GMA) microspheres to extract DNA from raw vegetables and highly processed foods of plant origin. Proposed small scale PCR‐ready DNA extraction protocol was comparable with a silica‐based DNeasy Plant Mini Kit (Qiagen) and classical CTAB extraction methods in quality and amplificability of DNA while it is less costly and time consuming.     

Activated sludge monitoring with combined respirometric-titrimetric measurements

A short review of different respirometric methods is presented, and advantages and disadvantages of different principles are discussed. In this study a combined respirometric-titrimetric set-up was applied to monitor the degradation processes during batch experiments with activated sludge. The respirometer consists of an open aerated vessel and a closed non-aerated respiration chamber. It is operated with two oxygen probes resulting in two sources of information on the oxygen uptake rate; both collected at a high frequency. The respirometer is combined with a titrimetric unit that keeps the pH of the activated sludge sample at a constant value through the addition of acid and/or base. The cumulative amount of added acid and base serves as a complementary information source on the degradation processes. Interpretation of respirometric data resulting from validation experiments (additions of acetate and urea as ammonium source) showed that the set-up provided reliable data. Data interpretation was approached in two ways: (1) via a basic calculation procedure, in which the oxygen uptake rates were obtained by an oxygen mass balance over the respiration chamber, and (2) via a model-based procedure in which substrate transport was included for a more accurate data interpretation. Simulation examples showed that the presence of substrate transport in the model may be crucial for a correct data interpretation, since experimental conditions (e.g. low flow rate) and/or the biodegradation kinetic parameters (e.g. high Ks) may otherwise lead to data interpretation errors. Earlier studies already pointed out that titrimetric data can be related to nitrification, and this was also confirmed in this study. However, in addition, it was shown here for experiments with acetate that the amount of acid dosed was clearly related to the amount of acetate degraded. This indicates that the titrimetric data can be used to study the carbon source degradation. For the titrimetric data in this study, a model-based analysis was however only applied for the nitrification process. For an experiment with ammonium, it was illustrated that the estimation of biodegradation kinetics on a combined respirometric-titrimetric data set significantly improves confidence intervals of the parameters compared to the parameter estimation based on respirometric or titrimetric data separately.     

液晶显示用玻璃的ITO镀层

在LCD生产中,从平板靶溅射ITO已是一项非常成熟的工艺,但如果转而采用旋转柱状靶,则可大大降低镀膜基板的成本。     

Intuitive physics in action and judgment: The development of knowledge about projectile motion.

Contrasts intuitive knowledge about projectile motion expressed in action with knowledge expressed in explicit judgments. In the action condition of Exp 1, children and adults threw a ball horizontally from different heights to hit targets on the floor; in the judgment condition the same Ss rated the respective launch speeds required. All age groups appropriately varied the launch speed with respect to both height of release and target distance in the action condition. In the judgment condition, however, kindergartners failed to integrate the relevant dimensions and even 4th graders and adults showed misconceptions of the speed–height relation. Exp 2 established that the speed gradations in the action condition did not critically depend on visual flight feedback or the availability of outcome information. It is concluded that perceptual-motor knowledge about projectile motion is distinct from naive, verbal-cognitive concepts of projectile motion and follows different developmental courses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phase-retrieval analysis of pre- and post-repair Hubble Space Telescope images

Phase-retrieval measurements of point-spread functions from the pre- and post-repair Hubble Space Telescope are presented. The primary goal was to determine the aberrations present in the second wide-field and planetary camera (WFPC2) to align and validate its corrective optics. With both parametric model-fitting techniques and iterative (Gerchberg-Saxton) methods, accurate measurements have been obtained of the WFPC2 and Hubble Space Telescope optics, including improved maps of the zonal errors in the mirrors. Additional phase-retrieval results were obtained for the aberrated, prerepair cameras and the corrected faint-object camera. The information has been used to improve models produced by point-spread-function simulation programs. On the basis of the measurements a conic constant for the primary mirror of κ = -1.0144 has been derived.     

Analysis of volatile compounds and triacylglycerol composition of fatty seed oil gained from flax and false flax

Linseed (Linum usitatissimum, L.) and camelina (Camelina sativa, L.) are ancient crops containing seed oils with a high potential for nutritional, medicinal, pharmaceutical and technical applications. In the present study, linseed and camelina oils of plant varieties grown under Central European climate conditions were examined with respect to their volatile and triacylglycerol (TAG) components. Solid‐phase microextraction was applied to the study of volatile compounds of several linseed and camelina oils, which have not been described prior to this publication. Hexanol (6.5–20.3% related to the total level of volatiles), trans‐2‐butenal (1.3–5.0%) and acetic acid (3.6–3.8%) could be identified as the main volatile compounds in the linseed oil samples. Trans‐2‐butenal (9.8%) and acetic acid (9.3%), accompanied by trans,trans‐3,5‐octadiene‐2‐one (3.8%) and trans,trans‐2,4‐heptadienal (3.6%), dominated the headspace of the examined camelina oil samples. TAG were analysed by MALDI‐RTOF‐MS and ESI‐IT‐MS, providing information about the total TAG composition of the oils as well as the fatty acid composition of the individual components. More than 20 TAG could be identified directly from whole linseed oil samples, mainly composed of linolenic (18:3), linoleic (18:2) and oleic (18:1) acid, and to a lesser degree of stearic (18:0) and palmitic (16:0) acid. While in linseed these TAG comprise more than 60% of the oils, Camelina sativa exhibited a wider range of more than 50 constituents, with a considerable amount (>35%) of TAG containing gadoleic (20:1) and eicosadienoic (20:2) acid.     

Integration of hydrogels with hard and soft microstructures

Hydrogels, i.e., water-swollen polymer networks, have been studied and utilized for decades. These materials can either passively support mass transport, or can actively respond in their swelling properties, enabling modulation of mass and fluid transport, and chemomechanical actuation. Response rates increase with decreasing hydrogel dimension. In this paper, we present three examples where incorporation of hydrogels into solid microstructures permits acceleration of their response, and also provides novel functional capabilities. In the first example, a hydrogel is immobilized inside microfabricated pores within a thin silicon membrane. This hydrogel does not have a swelling response under the conditions investigated, but under proper conditions it can be utilized as a part of an electrolytic diode. In the second example, hydrogels are polymerized under microcantilever beams, and their swelling response to pH or glucose concentration causes variable deflection of the beam, observable under a microscope. In the third example, swelling and shrinking of a hydrogel embedded in a microfabricated valve structure leads to chemical gating of fluid motion through that valve. In all cases, the small size of the system enhances its response rate.     

Volatile compounds and triacylglycerol composition of original Indian fatty plant oils

Some typical original Indian edible and non‐edible fatty plant oils were subject of our investigations. Fundamental research was done on analyzing volatile compounds using HS‐SPME‐GC‐MS. In addition, a sensorial evaluation was applied to receive data on the smell of the samples. Furthermore, the typical and prevailing triacylglycerols (TAG) were investigated by MALDI‐TOF‐MS. Mass spectra reflect the TAG profiles of the whole oil samples based on the detection of [M+Na]⁺ ions. Oil samples exhibit quite unique TAG profiles, which are suitable for rapid characterization of the original plant oils. The fatty acid composition of the corresponding TAG structures was calculated using lipid analysis software based on the known fatty acid composition. Relative quantification of TAG components was in good agreement with the literature, in case appropriate data are available so far.     

Synthesis,characterization and thermal analysis of Fe-doped boehmite nanofibres and nanosheets

It is important that one should have knowledge of the thermal stability of synthesized nanomaterials. In this research, thermal analyses of both dynamic and controlled rate thermal analysis (CRTA) combined with infrared emission spectroscopy have been used to determine the thermal stability of iron-doped boehmite. Iron-doped boehmite nanofibres with varying iron contents have been prepared at low temperature using hydrothermal treatment in the presence of non-ionic poly (ethylene oxide) surfactant. The TEM images show that the resulting nanostructures are predominantly nanofibres when Fe doping is less than 5%; in contrast, nanosheets are the dominant for 10% Fe-doped boehmite. No nanofibre was observed in the case of 20% Fe-doped boehmite, instead, nanotubes, nanosheets and iron-rich nanoparticles were formed. Both dynamic thermal analysis and CRTA show that Fe-doped boehmite nanomaterials dehydroxylate at higher temperatures than pure boehmite nanofibres. In general, the higher the doped Fe %, the higher the dehydroxylation temperature. The dehydroxylation temperature indicated in the infrared emission spectroscopy of doped boehmite nanomaterials is in harmony with those in other thermal analysis studies.     

Cucurbit[n]urils-related Multitopic Supramolecular Components: Design,Properties, and Perspectives

Cucurbit[n]urils (CBns) are an intriguing family of macrocyclic hosts whose chemistry has undergone rapid developments in recent decades. The initial interest in the synthesis, modifications and binding properties has shifted to areas focused on applications in drug storage, delivery, and release, external-stimuli responsive devices, and molecular nano-reactors. Since CBns are fruitfully complemented by cyclodextrins (CDs) in such systems, guest molecules that contain several binding sites are needed. These multitopic guests provide not only a scaffold for holding CBns and CDs together in appropriate arrangements but also allow for manipulation with supramolecular aggregates, e. g., reorganization or release of macrocycles. In this review, we summarize recent studies related to the design of multitopic guests. Binding motifs properties, the role of attractive or repulsive lateral interactions, the competition-compensation effect, and rotaxane versus pseudorotaxane manner are discussed.