Synthesis, thermal analysis, and spectroscopic and structural characterizations of zinc(II) complexes with salicylaldehydes

In this study, three new zinc(II) complexes with 5-substituted salicylaldehyde ligands (X-saloH) (X = 5-chloro, 5-nitro and 5-methyl) with the general formula [Zn(X-salo)₂(CH₃OH)n], (n = 0 or 2) were synthesized. An octahedral geometry was found for both the complexes [Zn(5-NO₂-salo)₂(CH₃OH)₂] and [Zn(5-Cl-salo)₂(CH₃OH)₂] by single-crystal X-ray diffraction analysis. These complexes were characterized also by spectroscopy (IR and ¹H-NMR). Simultaneous TG/DTG–DTA techniques were used to analyze their thermal behavior under inert atmosphere, with particular attention to determine their thermal degradation pathways, which was found to be a multi-step decomposition accompanied by the release of the ligand molecules. Finally, the kinetic analysis of the decomposition processes was performed by applying both the isoconversional Ozawa–Flynn–Wall (OFW) and the Kissinger–Akahira–Sunose (KAS) methods.     

C7‐Indole Amidations and Alkenylations by Ruthenium(II) Catalysis

C7?H‐functionalized indoles are ubiquitous structural units of biological and pharmaceutical compounds for numerous antiviral agents against SARS‐CoV or HIV‐1. Thus, achieving site‐selective functionalizations of the C7?H position of indoles, while discriminating among other bonds, is in high demand. Herein, we disclose site‐selective C7?H activations of indoles by ruthenium(II) biscarboxylate catalysis under mild conditions. Base‐assisted internal electrophilic‐type substitution C?H ruthenation by weak O‐coordination enabled the C7?H functionalization of indoles and offered a broad scope, including C?N and C?C bond formation. The versatile ruthenium‐catalyzed C7?H activations were characterized by gram‐scale syntheses and the traceless removal of the directing group, thus providing easy access to pharmaceutically relevant scaffolds. Detailed mechanistic studies through spectroscopic and spectrometric analyses shed light on the unique nature of the robust ruthenium catalysis for the functionalization of the C7?H position of indoles.     

Microfluidic ion-sensing devices

Quantitative determinations of ions in a variety of media have been performed traditionally via one of three approaches: optical instrumental methods (e.g., atomic absorption, and inductively-coupled plasma-optical emission or mass spectrometry), “wet” methods, or ion-selective sensors. Each of the approaches, though, possesses limitations including: power/reagent consumption and lack of portability for instrumental techniques; laborious sample-treatment steps for wet methods; and lack of selectivity and sensitivity with sensors when employed with complex samples. Microfluidic device have emerged as a solution to some of these challenges associated with ion analysis. Such systems can integrate multiple sample handling, calibration, and detection steps (“lab-on-a-chip” concept) into a footprint amenable to portability, while requiring small amounts of sample and power. Furthermore, devices can be constructed for multi-analyte detection, either through multiple parallel fluidic architectures or by using arrays of detection elements. This paper reviews recent progress in the development of total-analysis systems for ionic species. Fabrication techniques and various fluid-handling operations are discussed briefly, followed by a number of more mature strategies for microfluidic ion analysis. A variety of approaches expected to comprise the next generation of devices are also presented.     

Novel methodology for 3D reconstruction of carotid arteries and plaque characterization based upon magnetic resonance imaging carotid angiography data

In this study, we present a novel methodology that allows reliable segmentation of the magnetic resonance images (MRIs) for accurate fully automated three-dimensional (3D) reconstruction of the carotid arteries and semiautomated characterization of plaque type. Our approach uses active contours to detect the luminal borders in the time-of-flight images and the outer vessel wall borders in the T(1)-weighted images. The methodology incorporates the connecting components theory for the automated identification of the bifurcation region and a knowledge-based algorithm for the accurate characterization of the plaque components. The proposed segmentation method was validated in randomly selected MRI frames analyzed offline by two expert observers. The interobserver variability of the method for the lumen and outer vessel wall was -1.60%±6.70% and 0.56%±6.28%, respectively, while the Williams Index for all metrics was close to unity. The methodology implemented to identify the composition of the plaque was also validated in 591 images acquired from 24 patients. The obtained Cohen's k was 0.68 (0.60-0.76) for lipid plaques, while the time needed to process an MRI sequence for 3D reconstruction was only 30 s. The obtained results indicate that the proposed methodology allows reliable and automated detection of the luminal and vessel wall borders and fast and accurate characterization of plaque type in carotid MRI sequences. These features render the currently presented methodology a useful tool in the clinical and research arena.     

Simple, accurate formula for the average bit error probability of multiple-input multiple-output free-space optical links over negative exponential turbulence channels

In this Letter we investigate the error performance of multiple-input multiple-output free-space optical communication systems employing intensity modulation/direct detection and operating over strong atmospheric turbulence channels. Atmospheric-induced strong turbulence fading is modeled using the negative exponential distribution. For the considered system, an approximate yet accurate analytical expression for the average bit error probability is derived and an efficient method for its numerical evaluation is proposed. Numerically evaluated and computer simulation results are further provided to demonstrate the validity of the proposed mathematical analysis.     

Anti-Cancer Activity and Phenolic Content of Extracts Derived from Cypriot Carob (Ceratonia siliqua L.) Pods Using Different Solvents

Extracts derived from the Ceratonia siliqua L. (carob) tree have been widely studied for their ability to prevent many diseases mainly due to the presence of polyphenolic compounds. In this study, we explored, for the first time, the anti-cancer properties of Cypriot carobs. We produced extracts from ripe and unripe whole carobs, pulp and seeds using solvents with different polarities. We measured the ability of the extracts to inhibit proliferation and induce apoptosis in cancer and normal immortalized breast cells, using the MTT assay, cell cycle analysis and Western Blotting. The extracts’ total polyphenol content and anti-oxidant action was evaluated using the Folin–Ciocalteu method and the DPPH assay. Finally, we used LC-MS analysis to identify and quantify polyphenols in the most effective extracts. Our results demonstrate that the anti-proliferative capacity of carob extracts varied with the stage of carob maturity and the extraction solvent. The Diethyl-ether and Ethyl acetate extracts derived from the ripe whole fruit had high Myricetin content and also displayed specific activity against cancer cells. Their mechanism of action involved caspase-dependent and independent apoptosis. Our results indicate that extracts from Cypriot carobs may have potential uses in the development of nutritional supplements and pharmaceuticals.     

Quantitative Steiner/Schwarz-type symmetrizations

We establish some new quantitative results on Steiner/Schwarz-type symmetrizations, continuing the line of results from [Bourgain et al. (Lecture Notes in Math. 1376 (1988), 44–66)] on Steiner symmetrizations. We show that if we symmetrize high-dimensional sections of convex bodies, then very few steps are required to bring such a body close to a Euclidean ball.     

A Cassels-Schmidt theorem for non-homogeneous Markov chains

Let r be an integer not less than 2. Suppose that we have a (not necessarily homogeneous) Markov chain with state space {0,1,…,r−1} given by the sequence of r×r transition matrices

     

Thermodynamics of micellization of tapered statistical copolymers of ethylene oxide and propylene oxide in water

Two tapered statistical copolymers were prepared by the oxyanionic polymerization of ethylene oxide and propylene oxide and characterized by gel permeation chromatography and 13C NMR spectroscopy. We denote the copolymers t-E/P38 and t-E/P30, where E = oxyethylene, OCH2CH2, and P = oxypropylene, OCH2CH(CH3), and the number denotes the mole percentage P. In each case the copolymer chain length was ca. 100 oxyalkylene units. The association of the copolymers to form micelles in aqueous solution was checked by dynamic light scattering. The critical micelle temperatures (cmt) of the copolymers at several concentrations were determined by static light scattering and dye solubilization, and values of the apparent standard enthalpy of micellization (DeltamicHapp0) were obtained. For both copolymers, a low value of DeltamicHapp0 was found when the copolymer concentration exceeded ca. 150 g dm(-3).     

Building a new mind set in tomorrow fashion development through circular strategy models in the framework of waste management

Energy, food, and clothing are the three main components of humanity. Each one individually and all together contribute to climate change and CO₂ emissions, to the consumption of natural resources, as well as influencing social attitude and behaviour. The global trends of the fashion industry are projected to expand in value from $1.5 trillion in 2020 to about $2.25 trillion by 2025, presenting that the fashion request is on continual growth. As natural resources (e.g., water) to produce clothes and shoes are limited nowadays, more resource-efficient production pathways must be identified; moreover, natural materials must replace plastic fibres, natural colours must replace synthetic ones, and ‘buy-and throw-way philosophy’ must turn into ‘buy-less-and-these-are-needed’ as so to reduce the environmental footprint of the fashion sector. This work emphasized the necessity of developing a new business circular model for the fashion industry with the potential of providing plethora of economic opportunities in the framework of waste management. Clear vision and new strategy development in the fashion sector is proposed, including the involvement of customers, businesses and policy makers, driven by the promotion of circular economy through knowledge exchange, education as well as regulatory relief measures for a synergic transition towards the circularity of the fashion industry.