New fixed point theorems for $${\alpha}$$-$${H\Theta}$$HΘ-contractions in ordered metric spaces

Recently, Jleli and Samet [J. Inequal. Appl. (2014), 2014:38] introduced and studied a new contraction to prove a generalization of the Banach contraction principle. In this paper, we introduce the concept of \({\alpha}\)-\({H\Theta}\)-contraction with respect to a general family of functions H and we establish Jleli–Samet-type fixed point results in metric and ordered metric spaces. As an application of our results we deduce Suzuki-type fixed point results for \({H\Theta}\)-contractions. We also derive certain fixed and periodic point results for orbitally continuous generalized \({\Theta}\)-contractions. Moreover, we present an illustrative example to highlight the obtained improvements.     

A Hydrogel Microneedle Assay Combined with Nucleic Acid Probes for On-Site Detection of Small Molecules and Proteins

Point-of-care testing (POCT) of clinical biomarkers is critical to health monitoring and timely treatment, yet biosensing assays capable of detecting biomarkers without the need for costly external equipment and reagents are limited. Blood-based assays are, specifically, challenging as blood collection is invasive and follow-upprocessing is required. Here, we report a versatile assay that employs hydrogel microneedles (HMNs) to extract interstitial fluid (ISF), in a minimally invasive manner integrated with graphene oxide-nucleic acid (GO.NA)-based fluorescence biosensor to sense the biomarkers of interest in situ. The HMN-GO.NA assay is supplemented with a portable detector, enabling a complete POCT procedure. Our system could successfully measure four clinically important biomarkers (glucose, uric acid (UA), insulin, and serotonin) ex vivo, in addition, to accurately detecting glucose and UA in vivo.     

A new and efficient one-pot procedure for the synthesis of 2-styrylquinolines

A one-pot combination of a modified Friedländer annulation and a Knoevenagel condensation provides 2-styrylquinolines in good to excellent yields. A variety of substrates are reacted in one-pot in the presence of 1-methylimidazolium trifluoroacetate ([Hmim]TFA).     

Super-resolution and Raman chemical imaging: from multiple low resolution images to a high resolution image

Imaging in Raman spectroscopy is a valuable tool for analytical chemistry. Although molecular characterization at micron level is achieved for many applications, it usually fails producing chemical images of micron size samples as expected in chemical, environmental and biological analysis. The aim of the work is to introduce the potential of super-resolution in vibrational spectroscopic imaging. This original chemometrics approach uses several low resolution images of the same sample in order to retrieve a higher resolution chemical image. It is thus possible to overcome in a certain way some physical and instrumentals limitations. To illustrate the methodology, sub-micronic details of a Si/Au sample are retrieved from low resolution images with different super-resolution algorithms. The better results are obtained with Iterative L2/Bilateral Total Variation regularization method. The use of a regularization procedure gives also better results since its first property is to preserve edges during the reconstruction of the super-resolved image. This concept of chemical image data processing should open new analytical opportunities.     

Integrated fuzzy AHP and fuzzy VIKOR model for supplier selection in an agile and modular virtual enterprise

In this ever-changing world, organizations need to outsource parts of their processes for having agile response to market’s needs and varying demands. Because of temporal nature of virtual enterprises (VE’s), the situation of outsourcing process in this kind of organizations is a vital situation. The main idea of this paper aims to present a decision-making framework for specific area that is appropriated for complex states. Its contribution is developing a fuzzy VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) method and combining it with fuzzy analytic hierarchy process (AHP). This extension suitable for decision-making situations which is faced with mixture appraisement that simultaneously regarded to both “group utility” or majority and “individual regret” of the opponent. The Integrated and developed model suits to inconsistent conditions that we face to collection of criteria and subcriteria that should satisfy some of them collectively and simultaneously and in other attainment of some individual criteria is desirable. This framework then extended to a case study with varied criteria for outsourcing process.     

Transetherification of Allylic and Benzylic Ethers in the Presence of Ferric Ion

Alcoholysis of allylic, secondary and tertiary benzylic ethers is proceeded efficiently in the presence of catalytic amounts of ferric ion as anhydrous FeCl₃ and Fe(ClO₄)₃.     

Application of BU4N+HSO4 − as an Ionic Liquid and Acid Catalyst for Thioacetalization of Aldehydes and Ketones

A variety of carbonyl containing compounds have been successfully reacted with 1,2-ethanedithiol in a thioacetylization reaction using tetrabutylammonium hydrogensulfate as a mild and efficient catalyst. Aldehydes and ketones react with good to excellent yields under mild conditions.     

The Schur multiplier of p-groups with large derived subgroup

For any given p-group of order p ⁿ (n ≥ 4) with derived subgroup of order p ^n-2 we will show that the order of its Schur multiplier is less than |G ^'|/2 when p = 2 and |G ^'| in the other cases.     

Homogeneous Liquid–Liquid Microextraction Via Flotation Assistance (HLLME-FA) Method for the Pretreatment of Organochlorine Pesticides in Aqueous Samples and Determination by GC–MS

This work proposes a new, rapid and simple homogeneous liquid–liquid microextraction via flotation assistance technique for the analysis of six organochlorine pesticides in water samples. A special extraction cell was used to facilitate collection of the low-density solvent extract. No centrifugation was required in this procedure. Determination was carried using gas chromatography–mass spectrometry. The water sample solution was then added into the extraction cell containing appropriate mixture of extract and homogeneous solvents. In the first step, a homogeneous solution and then with the continuation of water sample injection, a cloudy solution was formed. Using air flotation, the organic solution was collected at the conical part of the designed cell. The optimized levels of effective parameters were found based on response surface methodology approach. Applying the optimized conditions to the system understudy, the limits of detection of all target analytes were obtained in the range of 1.4–7 ng mL⁻¹, while the precisions were found to be in the range of 11.08–14.87 (RSD, n = 3). The linearity of the method lay in the range of 10–150 ng mL⁻¹ with the coefficients of correlation (r ²) ranging from 0.998 to 0.999.

     

Calix[4]arene-based metal-organic frameworks: towards hierarchically porous materials

An upper rim-functionalised calix[4]arene dicarboxylic acid (H(2)caldc) has been used to prepare four metal-organic frameworks, three of which have been structurally characterised and shown to form two- or three-dimensional network structures. Simulations suggest that such networks are likely to display interesting selectivity to guest molecules.