Role of eye movements in chromatic induction

There exist large interindividual differences in the amount of chromatic induction [Vis. Res. 49, 2261 (2009)]. One possible reason for these differences between subjects could be differences in subjects' eye movements. In experiment 1, subjects either had to look exclusively at the background or at the adjustable disk while they set the disk to a neutral gray as their eye position was being recorded. We found a significant difference in the amount of induction between the two viewing conditions. In a second experiment, subjects were freely looking at the display. We found no correlation between subjects' eye movements and the amount of induction. We conclude that eye movements only play a role under artificial (forced looking) viewing conditions and that eye movements do not seem to play a large role for chromatic induction under natural viewing conditions.     

Engineered humanized diabodies for microPET imaging of prostate stem cell antigen-expressing tumors

We have previously demonstrated preclinical in vivo targeting of prostate stem cell antigen (PSCA) using a humanized anti-PSCA 2B3 monoclonal antibody (mAb). However, humanization resulted in 5-fold loss of apparent affinity relative to the parental mAb (1 nM). In this study, diabodies (scFv dimers of 55 kDa) were generated from 2B3 including variants with different linker lengths as well as back-mutations to original murine residues to improve affinity. Parental 2B3 (p2B3) and back-mutated 2B3 (bm2B3) diabodies (Dbs) with five- or eight-amino acid linkers (p2B3-Db5, p2B3-Db8, bm2B3-Db5 and bm2B3-Db8) were evaluated for binding to PSCA by flow cytometry and affinities were determined by surface plasmon resonance. Back-mutation restored the affinity from 5.4 to 1.9 nM. Stability, evaluated by size exclusion, revealed that diabodies with eight-residue linkers existed as a mixture of dimeric and monomeric species at low concentrations (相似文献   

Determination of structural building blocks in heavy petroleum systems by collision-induced dissociation Fourier transform ion cyclotron resonance mass spectrometry

Collision-induced dissociation Fourier Transform ion cyclotron resonance mass spectrometry (CID-FTICR MS) was developed to determine structural building blocks in heavy petroleum systems. Model compounds with both single core and multicore configurations were synthesized to study the fragmentation pattern and response factors in the CID reactions. Dealkylation is found to be the most prevalent reaction pathway in the CID. Single core molecules exhibit primarily molecular weight reduction with no change in the total unsaturation of the molecule (or Z-number as in chemical formula C(c)H(2c+Z)N(n)S(s)O(o)VNi). On the other hand, molecules containing more than one aromatic core will decompose into the constituting single cores and consequently exhibit both molecular weight reduction and change in Z-numbers. Biaryl linkage, C(1) linkage, and aromatic sulfide linkage cannot be broken down by CID with lab collision energy up to 50 eV while C(2)+ alkyl linkages can be easily broken. Naphthenic ring-openings were observed in CID, leading to formation of olefinic structures. Heavy petroleum systems, such as vacuum resid (VR) fractions, were characterized by the CID technology. Both single-core and multicore structures were found in VR. The latter is more prevalent in higher aromatic ring classes.     

Metabolomics: a valuable tool for stem cell monitoring in regenerative medicine

Metabolomics is a method for investigation of changes in the global metabolite profile of cells. This paper discusses the technical application of the approach, considering metabolite extraction, separation, mass spectrometry and data interpretation. A particular focus is on the application of metabolomics to the study of stem cell physiology in the context of biomaterials and regenerative medicine. Case studies are used to illustrate key points, focusing on the use of metabolomics in the examination of mesenchymal stem cell responses to titania-nanopillared substrata designed for orthopaedic applications.     

Simultaneous quantification of opiates, cocaine, and metabolites in hair by LC-APCI-MS/MS

A quantitative LC-APCI-MS/MS method for simultaneous measurement of opiates, cocaine, and metabolites in hair was developed and validated. Cocaine and opiates were extracted from pulverized hair via sonication in methanol at 37 degrees C for 3 h. Samples were cleaned up using solid-phase extraction. LC separation was achieved in 20 min with identification and quantification by selected reaction monitoring. Calibration by linear regression analysis utilized deuterated internal standards and a weighting factor of 1/x (R(2) > 0.998). Limits of quantification (LOQ) ranged from 17 to 50 pg/mg for cocaine and metabolites and were 83 pg/mg for opiates. Standard curves were linear from the LOQ to 5000 pg/mg for cocaine and metabolites, except benzoylecgonine (2500 pg/mg). Opiate standard curves were linear from the LOQ to 12500 pg/mg. Accuracy ranged from 84 to 115% for all quantitative analytes. Precision, % relative standard deviation, was less than 11.0% for all analytes. Methanolic sonication produced less than 5% hydrolysis of cocaine and 6-acetylmorphine. The method should be useful for studying cocaine and opiate distribution into hair.     

OPAX: A new transfer path analysis method based on parametric load models

Since its first publication in the beginning of the 1980s, transfer path analysis (TPA) has evolved into a widely used tool for noise and vibration troubleshooting and internal load estimation, for single source and multivariate problems. One of the main bottlenecks preventing its even more widespread use in the vehicle development process is the test time needed to build the full data model, requiring not only in-operation tests but also extensive frequency response function (FRF) measurements.As a consequence, several new approaches, such as operational TPA, have appeared over the past years attempting to circumvent this limitation. These methods attract quite some attention as they only require operational data measured at the path references and target locations. However, despite being time-efficient, these methods suffer from several limitations that can lead to incorrect path contribution interpretations and wrong engineering decisions.Hence, a new TPA approach is proposed, providing a good compromise between path accuracy and measurement time. The method is referred to as OPAX as it essentially uses in-operation data complemented with a minimal set of extra tests with forced excitation. The key idea of OPAX is the use of parametric models for identifying the operational loads. This makes the method scalable, enabling the engineer to use a simple model based on a small amount of measurement data for quick troubleshooting or increase accuracy using a more complex model together with additional measurements.     

Communicating Particles: Identification Taggant and Temperature Recorder in One Single Supraparticle

“Communicating particles” are reported that combine an identification (ID) taggant and a temperature recorder in one single entity—a micron-scaled supraparticle. The optical information carriers within the hybrid inorganic-organic supraparticles are three different types of luminescent nanoparticles, which can be read-out using single-wavelength excitation. These three nanoparticle types are assembled into a core-satellite structure via a two-step droplet evaporation technique. The core is built-up from Tb³⁺ and Eu³⁺-doped nanophosphors, providing an environmentally stable ID that is easily tunable through ratiometric spectral coding. This core is surrounded by organic, dye-doped polymer nanoparticle satellites, acting as thermal-history-recorders of their environment. Exposed to a threshold temperature, the luminescence of the utilized 7-diethylamino-4-methylcoumarin-doped polymer nanoparticles is irreversibly quenched. This “turn-off ” signal response is attributed to conformational changes in the dyes’ excited state and an alteration of their molecular environment, respectively, triggered by the polymer nanoparticles’ glass transition. Thus, the sensitivity of the temperature recorder can be configured over a wide temperature range by varying the dye-hosting polymer. At the same time, the ID of the particle, stemming from its inorganic building blocks, stays unaffected, thus stable against thermal changes. The idea of communicating particles introduces a promising concept for smart additives.     

The 2nd Alpine Winter Conference on Medicinal and Synthetic Chemistry

The second biannual Alpine Winter Conference on Medicinal and Synthetic Chemistry (short: Alpine Winter Conference) took place January 19–23, 2020, in St. Anton in western Austria. There were roughly 180 attendees from around the globe, making this mid-sized conference particularly conducive to networking and exchanging ideas over the course of four and a half days. This report summarizes the key events and presentations given by researchers working in both industry and academia.