Determination of the Free Radical Scavenging Activity of Lycium Extracts

Lycium species growing in Turkey have not so far been studied sufficiently. For this reason, non-polar and polar extracts obtained from the fruits of Lycium barbarum L. and L. Ruthenicum Murray (Solanaceae) were assessed both in vitro for their potential as free radical scavenger crude extracts and their phenolic composition. Fruits of Lycium species were sequentially extracted with petroleum ether, ethyl acetate, methanol, n-butanol, and water in a Soxhlet extractor. All the extracts were assessed for the scavenging of the nitrogen-centered free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH^.) by in vitro method. Furthermore, the composition of each extract was investigated both in terms of its Folin-Ciocalteau reactive components and its qualitative content. The phenolic compounds within the extracts were determined as benzoic acid and hydroxycinnamic acid derivatives, flavonoids, and anthocyanins according to their retention time and UV spectral data by HPLC-DAD system.     

Hazardous metal geochemistry of sedimentary phosphate rock used for fertilizer (Maz?dag, SE Anatolia, Turkey)

Composition of phosphate rocks mostly depend on their type and origin. Sedimentary rocks contain high concentration of heavy metals. Phosphate rocks are mainly used for the manufacturing of phosphate fertilizers. The contents of heavy metals Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn, as well as rare earth elements Ce, La, and Th were determined in sedimentary phosphate rock used for production of fertilizer in Turkey. The Kasrik-Semikan, Mazidag (Mardin, SE Anatolia, Turkey) high-grade phosphate rock used in this study is situated near the border with Syria and was deposited during the Turonian and Senonian (Cretaceous) ages. Total phosphorus (P) concentration in the rock is 18.5% on the average. Microwave acid digestion (MW-AD) followed by ?nductively Coupled Plasma-Optical Emission Spectrophotometry (ICP-OES) was carried out for the determination of all the elements of interest in phosphate rock. The results revealed that hazardous metal content of the phosphate rock was lower in Mazidag phosphate than that in samples imported from other countries and were within the safety limits.     

A data mining approach to forecast behavior

This study presents a data mining analysis of forecasting patterns in a supply chain. Multiple customers who are auto manufacturers order from a large auto parts supplier. The auto manufacturers provide forecasts for future orders and update them before the due date. The supplier uses these forecasts to plan production in advance. The accuracy of the forecasts varies from customer to customer. We provide a framework to analyze the forecast performance of the customers. There are different complexities in forecasts that are captured from our data set. Daily flow analysis helps to transform data and obtain accuracy ratios of forecasts. Customers are then classified based on their forecast performances. We demonstrate the application of some recent developments in clustering and pattern recognition analysis to performance analysis of customers.     

Effective cut-offs for modes on helical fibres

Every mode of a single-mode or multimode helical fibre is always leaky but, for practical purposes, can be treated as being bound with an effective cut-off wavelength. The leakage loss for each mode is quantified, showing that, for fixed core offset and source wavelength, the cut-off pitch increases with increasing mode order. The value of the cut-off pitch for each mode is in agreement with experimental measurements.     

Combining Modular Ligation and Supramolecular Self‐Assembly for the Construction of Star‐Shaped Macromolecules

A well‐defined random copolymer of styrene (S) and chloromethylstyrene (CMS) featuring lateral chlorine moieties with an alkyne terminal group is prepared (P(S‐co‐CMS), = 5500 Da, PDI = 1.13). The chloromethyl groups are converted into Hamilton wedge (HW) entities (P(S‐co‐HWS), = 6200 Da, PDI = 1.13). The P(S‐co‐HWS) polymer is subsequently ligated with tetrakis(4‐azidophenyl)methane to give HW‐functional star‐shaped macromolecules (P(S‐co‐HWS))₄, = 25 100 Da, PDI = 1.08). Supramolecular star‐shaped copolymers are then prepared via self‐assembly between the HW‐functionalized four‐arm star‐shaped macromolecules ( P(S‐co‐HW )) ₄ and cyanuric acid (CA) end‐functionalized PS (PS–CA, = 3700 Da, PDI = 1.04), CA end‐functionalized poly(methyl methacrylate) (PMMA–CA, = 8500 Da, PDI = 1.13) and CA end‐functionalized polyethylene glycol (PEG–CA, = 1700 Da, PDI = 1.05). The self‐assembly is monitored by ¹H NMR spectroscopy and light scattering analyses.     

Single Chain Folding of Synthetic Polymers by Covalent and Non‐Covalent Interactions: Current Status and Future Perspectives

The present feature article highlights the preparation of polymeric nanoparticles and initial attempts towards mimicking the structure of natural biomacromolecules by single chain folding of well‐defined linear polymers through covalent and non‐covalent interactions. Initially, the discussion focuses on the synthesis and characterization of single chain self‐folded structures by non‐covalent interactions. The second part of the article summarizes the folding of single chain polymers by means of covalent interactions into nanoparticle systems. The current state of the art in the field of single chain folding indicates that covalent‐bond‐driven nanoparticle preparation is well advanced, while the first encouraging steps towards building reversible single chain folding systems by the use of mutually orthogonal hydrogen‐bonding motifs have been made.