Wall NMR in the weak ferromagnets YCrO3 and LuCrO3

Complex NMR spectra, consisting of a maximum of six resonance lines, were observed in the domain walls of YCrO₃ and LuCrO₃ and studied as a function of temperature and the in-plane magnetic field. The distribution of the NMR frequency across the domain wall was calculated taking into account the anisotropy of hyperfine fields and quadrupolar interactions. The calculated frequency distribution was used to simulate the shape of the NMR spectra in YCrO₃. The analysis of theoretical spectra in the centext of our experimental results and in particular the asymmetric behaviour of resonance lines in a magnetic field indicate the critical importance of the relaxation processes on the shape of NMR spectra. This conclusion was confirmed by an experiment in which the relaxation was simulated in YFeO₃. The NMR spectrum in LuCrO₃ can be explained by the same model.     

An equity approach to stream water quality management

A model for stream water quality management with particular emphasis on applicability in Turkey is developed via mathematical programming. A new criterion of equity is introduced and the model is formulated as a quadratic programming problem with two objectives, namely equity among dischargers and minimization of total cost. The model is also applied to a hypothetical stream and compared with other more common water quality management programs.     

Bestimmung der Geschwindigkeitskonstante der Bromierungsreaktion von Acetanilid mittels Titrationsmethode in diffuser Schicht an der rotierenden Ring-Scheiben-Elektrode

The kinetics of the bromination of acetanilide has been studied with the diffusion layer titration method. The results have been obtained using the apparatus which consists of the ring-disc electrode and an amperostat-potentiostat system. Dependence of the ring current on the disc current has been determined as a function of rotation speeds of the electrode, of the solution concentration and temperature. It has been shown the bromination reaction of acetanilide exhibits by first order kinetics. In that case Br₂ and Br₃ ^? are the brominating species. The rate of bromination changes with the concentration of the Br^? ions. This reaction rate depends on reactions of molecular bromine with acetanilide. For 0.033<[Br^?]<0.173M the rate constant changes in the following range: $$17530M^{ - 1} s^{ - 1}< k< 6400M^{ - 1} s^{ - 1} ([H + ] = 1,34;T = 298K)$$      

Studies on poly(ethylene terephthalate)/cotton blends by differential scanning calorimetry

DSC curves of polyster/cotton blends indicate that the glass transition temperature,T _g, of cotton varies with the blend composition. Standard curves for quality control purposes are presented and are based on either the cotton or PET transition peak areas. Factors that contribute to the size of the peak areas were determined: a composition coefficient factor and a thermal coefficient factor.

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Zusammenfassung Die DSC-Kurven von Polyster/Baumwoll-Gemischen zeigen, dass die Glas-Übergangstemperatur (T _g der Baumwolle sich mit der Zusammensetzung des Gemisches ändert. Standardkurven für Qualitätskontrollen werden gezeigt, welche auf den Übergangspeakflächen der Baumwolle oder des PETs beruhen. Die zur Grösse der Peakfläche beitragenden Faktoren wurden bestimmt: ein Zusammensetzungskoeffizient und ein thermischer Koeffizient.

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Résumé Les courbes DSC des combinaisons polyester/coton indiquent que la température de transition vitreuseT _g du coton varie avec la composition. On présente des courbes types pour le contrôle de la qualité d'après les surfaces des pics de transition du coton ou du PET. On a déterminé les facteurs qui influencent la dimension des surfaces des pics: l'un est en rapport avec la composition et l'autre avec le coefficient thermique.

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Snakes and perturbed random walks

We study some properties of random walks perturbed at extrema, which are generalizations of the walks considered, e.g., by Davis (1999) and Tóth (1996). This process can also be viewed as a version of an excited random walk, recently studied by many authors. We obtain several properties related to the range of the process with infinite memory and prove the strong law, the central limit theorem, and the criterion for the recurrence of the perturbed walk with finite memory. We also state some open problems. Our methods are predominantly combinatorial and do not involve complicated analytic techniques.     

Synthetically Tuning the 2‐Position of Halogenated Quinolines: Optimizing Antibacterial and Biofilm Eradication Activities via Alkylation and Reductive Amination Pathways

Agents capable of eradicating bacterial biofilms are of great importance to human health as biofilm‐associated infections are tolerant to our current antibiotic therapies. We have recently discovered that halogenated quinoline (HQ) small molecules are: 1) capable of eradicating methicillin‐resistant Staphylococcus aureus (MRSA), methicillin‐resistant Staphylococcus epidermidis (MRSE) and vancomycin‐resistant Enterococcus faecium (VRE) biofilms, and 2) synthetic tuning of the 2‐position of the HQ scaffold has a significant impact on antibacterial and antibiofilm activities. Here, we report the chemical synthesis and biological evaluation of 39 HQ analogues that have a high degree of structural diversity at the 2‐position. We identified diverse analogues that are alkylated and aminated at the 2‐position of the HQ scaffold and demonstrate potent antibacterial (MIC≤0.39 μm ) and biofilm eradication (MBEC 1.0–93.8 μm ) activities against drug‐resistant Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecium strains while demonstrating <5 % haemolysis activity against human red blood cells (RBCs) at 200 μm . In addition, these HQs demonstrated low cytotoxicity against HeLa cells. Halogenated quinolines are a promising class of antibiofilm agents against Gram‐positive pathogens that could lead to useful treatments against persistent bacterial infections.     

On-tissue protein identification and imaging by MALDI-Ion mobility mass spectrometry

MALDI imaging mass spectrometry (MALDI-IMS) has become a powerful tool for the detection and localization of drugs, proteins, and lipids on-tissue. Nevertheless, this approach can only perform identification of low mass molecules as lipids, pharmaceuticals, and peptides. In this article, a combination of approaches for the detection and imaging of proteins and their identification directly on-tissue is described after tryptic digestion. Enzymatic digestion protocols for different kinds of tissues—formalin fixed paraffin embedded (FFPE) and frozen tissues—are combined with MALDI-ion mobility mass spectrometry (IM-MS). This combination enables localization and identification of proteins via their related digested peptides. In a number of cases, ion mobility separates isobaric ions that cannot be identified by conventional MALDI time-of-flight (TOF) mass spectrometry. The amount of detected peaks per measurement increases (versus conventional MALDI-TOF), which enables mass and time selected ion images and the identification of separated ions. These experiments demonstrate the feasibility of direct proteins identification by ion-mobility-TOF IMS from tissue. The tissue digestion combined with MALDI-IM-TOF-IMS approach allows a proteomics “bottom-up” strategy with different kinds of tissue samples, especially FFPE tissues conserved for a long time in hospital sample banks. The combination of IM with IMS marks the development of IMS approaches as real proteomic tools, which brings new perspectives to biological studies.     

Proteomic maps-toxicity relationship of halocarbons studied with similarity index and genetic algorithm

In this work we analyzed proteomic maps obtained from hepatocytes, which were treated with 14 halocarbons. A similarity index was introduced as a robust measure of similarity between two maps or between two selections of spots within the maps. A searching algorithm was used to identify the spots that may play an important role in toxicity mechanism. The highest correlation coefficients obtained between the similarity index and biological parameter were larger than 0.9.