bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detectors in Capillary Electrophoresis
Authors: Tůma Petr , Opekar František 
Published: November 2015

Abstract

This chapter presents a fundamental overview over current detection systems used in capillary electrophoresis with the focus on modern trends. Attention is paid mainly to
UV
‐
Vis
absorption spectrometric, fluorescence, amperometric, contactless conductivity, and electrochemiluminiscence detectors. Each detection technique is characterized by fundamental physical–chemical principle, designs of detection cells, and examples of typical applications are presented. Special attention is given to combinations of detection techniques used in multidimensional detection systems.
Two‐Dimensional Liquid Chromatography
Authors: Sarrut Morgan , Marchetti Nicola , Heinisch Sabine 
Published: November 2015

Abstract

Two‐dimensional liquid chromatography saw significant developments in handling the need to separate a rising number of highly complex samples. 2
D
‐
LC
is the coupling of the separation of a complex sample by a first
LC
method to a second different
LC
method. This chapter details the different ways to perform such coupling 2
D
‐
LC
methods: heart‐cutting method; offline, online, and stop‐flow methods, and comprehensive
LC
×
LC
. The critical parameter is peak capacity that is defined and calculated in classical
LC
and 2
D
‐
LC
methods. It is linked to the orthogonality of the separation power of the two coupled
LC
methods. From a practical point of view, the effective peak capacity is compared with the theoretical one. Analysis time and dilution are also two critical parameters in 2
D
‐
LC
that need to be considered. All parameters are presented describing a practical method development.
Sampling Strategies: Statistics of Sampling
Authors: Bodnar Małgorzata , Konieczka Piotr , Namieśnik Jacek 
Published: November 2015

Abstract

Each step of the analytical procedure has a significant influence on the final result of the analysis. In the majority of cases the analytical procedure encompasses sampling because the analysis of the entire object (material) is usually not possible. Thus it is necessary to include the uncertainty related to sampling procedure in the uncertainty budget calculations. In the paper:

the most important properties of the analysed object, which influence the method of sample collection and handling,

elements of the sampling strategy,

methods of estimating uncertainty is presented in the EURACHEM Guide and also in the Theory of Sampling (TOS),

were described.
Solid‐Phase Microextraction
Authors: Mehdinia Ali , Aziz‐Zanjani Mohammad Ovais 
Published: November 2015

Abstract

Since its introduction in 1990, solid phase microextraction (SPME) method has been widely applied as a convenient and rapid sample preparation technique. The developments in SPME which make it flexible for different applications could be divided into the following categories: (i) emergence of novel SPME configurations and devices, (ii) application of manifold homemade materials as SPME coatings or sorbents, and (iii) development of different techniques for preparing SPME coatings. The aim of this chapter is to discuss about the fundamentals of the SPME as well as its recent advances. These advances were oriented to address the needs for an efficient, rapid, reproducible and selective extraction, suitable for laboratory and in‐vivo analysis, and on‐site sampling.
Novel Approach for Modeling the Dynamics of Fiber Breakage in Polymer Matrix Composites during Capillary Extrusion
Authors: Sporleder F. , Carella J. M. , Dorao C. A. , Ludueña L. N. 
Published: November 2015

ABSTRACTIn this work, a population balance equation (PBE) model is used to predict the evolution of the fiber breakage in thermoplastic polymer/short‐fiber composites during capillary extrusion. The least squares spectral method was used to solve the resulting integrodifferential equation. The differences found between the experimental and simulated data were attributed to the selected breakage and redistribution functions. An experimental setup is proposed to find accurate breakage functions for this problem. The results indicate that the application of the PBE for such a breakage process could be a powerful tool for the design of injection molding molds.
Dose‐Dependent Response of Personal Glucose Meters to Nicotinamide Coenzymes: Applications to Point‐of‐Care Diagnostics of Many Non‐Glucose Targets in a Single Step
Authors: Zhang Jingjing , Xiang Yu , Wang Miao , Basu Ananda , Lu Yi 
Published: November 2015

AbstractWe report a discovery that personal glucose meters (PGMs) can give a dose‐dependent response to nicotinamide coenzymes, such as the reduced form of nicotinamide adenine dinucleotide (NADH). We have developed methods that take advantage of this discovery to perform one‐step homogeneous assays of many non‐glucose targets that are difficult to recognize by DNAzymes, aptamers, or antibodies, and without the need for conjugation and multiple steps of sample dilution, separation, or fluid manipulation. The methods are based on the target‐induced consumption or production of NADH through cascade enzymatic reactions. Simultaneous monitoring of the glucose and L‐lactate levels in human plasma from patients with diabetes is demonstrated and the results are comparable to those from current standard test methods. Since a large number of commercially available enzymatic assay kits utilize NADH in their detection, this discovery will allow the transformation of almost all of these clinical lab tests into POC tests that use a PGM.
Total Synthesis and Structural Reassignment of Aspergillomarasmine A
Authors: Liao Daohong , Yang Shaoqiang , Wang Jianyu , Zhang Jian , Hong Benke , Wu Fan , Lei Xiaoguang 
Published: November 2015

AbstractThe increase and spread of Gram‐negative bacteria that resistant are to almost all currently available β‐lactam antibiotics is a major global health problem. The primary cause for drug resistance is the acquisition of metallo‐β‐lactamases such as metallo‐β‐lactamase‐1 (NDM‐1). The fungal natural product aspergillomarasmine A (AMA), a fungal natural product, is an inhibitor of NDM‐1 and has shown promising in vivo therapeutic potential in a mouse model infected with NDM‐1‐expressing Gram‐negative bacteria. The first total synthesis and stereochemical configuration reassignment of aspergillomarasmine A is reported. The synthesis highlights a flexible route and an effective strategy to achieve the required oxidation state at a late stage. This modular route is amenable to the efficient preparation of analogues for the development of metallo‐β‐lactamase inhibitors to potentiate β‐lactam antibiotics.
Accelerated weathering properties of compatibilized composites made from recycled HDPE and nonmetallic printed circuit board waste
Authors: Muniyandi Shantha Kumari , Sohaili Johan , Hassan Azman 
Published: November 2015

ABSTRACTThe main aim of this work is to examine the influence of the contents of nonmetallic printed circuit board (PCB) waste component on the photodegradation of recycled high‐density polyethylene (rHDPE) composites. The properties tested were chemical changes, flexural properties, color stability, water absorption, leaching properties, and crystallinity changes of the composites after exposure to 2,000 h of accelerated weathering. Surface degradation for composites with nonmetallic PCB was less compared to unfilled rHDPE mainly because glass fibers covered almost the whole surface of specimens, acting as a protective layer, thus, slowing down the photodegradation reaction. Incorporation of compatibilizer in rHDPE/PCB composites had played an important role in resisting degradation due to UV exposure. All the composite samples became lighter in the early stages of weathering exposure; however, compatibilized composites showed less lightening and reduction on strength and modulus. Carbonyl index increases with exposure time indicating that the oxidation reaction continuously occurred during the aging process. Incorporation of compatibilizer had successfully reduced the water absorption uptake by the composites and effectively delayed some degradation properties of weathering. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43110.
Assessment of learning gains in a flipped biochemistry classroom
Authors: Ojennus Deanna Dahlke 
Published: November 2015

AbstractThe flipped classroom has become an increasingly popular pedagogical approach to teaching and learning. In this study, learning gains were assessed in a flipped biochemistry course and compared to gains in a traditional lecture. Although measured learning gains were not significantly different between the two courses, student perception of learning gains did differ and indicates a higher level of satisfaction with the flipped lecture format. © 2015 by The International Union of Biochemistry and Molecular Biology, 44:20–27, 2016.
Flexibility of C3h‐Symmetrical Linkers in Tris‐oligonucleotide‐Based Tetrahedral Scaffolds
Authors: Panagiotidis Christos , Kath‐Schorr Stephanie , von Kiedrowski Günter 
Published: November 2015

AbstractFlexibility of tris‐oligonucleotides is determined by the length of their connecting hydrocarbon chains. Tris‐oligonucleotides are branched DNA building blocks with three oligonucleotide arms attached to a C3h‐symmetrical linker core at these chains. Four tris‐oligonucleotides hybridise into a tetrahedral nanocage by sequence‐determined self‐assembly. The influence of methylene, ethylene and propylene chains was studied by synthesising sets of tris‐oligonucleotides and analysing the relative stability of the hybridisation products against digestion by mung bean nuclease by using gel electrophoresis. Linkers with ethylene chains showed sufficient flexibility, whereas methylene‐chain linkers were too rigid. Tris‐oligonucleotides based on the latter still formed tetrahedral scaffolds in intermixing experiments with linkers of higher flexibility. Thus, a new generation of versatile isocyanurate‐based linkers was established.
Bottom‐Up Fabrication of Single‐Layered Nitrogen‐Doped Graphene Quantum Dots through Intermolecular Carbonization Arrayed in a 2D Plane
Authors: Li Rui , Liu Yousong , Li Zhaoqian , Shen Jinpeng , Yang Yuntao , Cui Xudong , Yang Guangcheng 
Published: November 2015

AbstractA single‐layered intermolecular carbonization method was applied to synthesize single‐layered nitrogen‐doped graphene quantum dots (N‐GQDs) by using 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB) as the only precursor. In this method, the gas produced in the pyrolysis of TATB assists with speeding up of the reactions and expanding the layered distance, so that it facilitates the formation of single‐layered N‐GQDs (about 80 %). The symmetric intermolecular carbonizations of TATB arrayed in a plane and six nitrogen‐containing groups ensure small, uniform sizes (2–5 nm) of the resulting products, and provide high nitrogen‐doping concentrations (N/C atomic ratio ca. 10.6 %). In addition to release of the produced gas, TATB is almost completely converted into aggregated N‐GQDs; thus, relatively higher production rates are possible with this approach. Investigations show that the as‐produced N‐GQDs have superior fluorescent characteristics; high water solubility, biocompatibility, and low toxicity; and are ready for potential applications, such as biomedical imaging and optoelectronic devices.
Tuning the Electron Acceptor in Phthalocyanine‐Based Electron Donor–Acceptor Conjugates
Authors: Sekita Michael , Jiménez Ángel J. , Marcos M. Luisa , Caballero Esmeralda , Rodríguez‐Morgade M. Salomé , Guldi Dirk M. , Torres Tomás 
Published: November 2015

AbstractZinc phthalocyanines (ZnPc) have been attached to the peri‐position of a perylenemonoimide (PMI) and a perylenemonoanhydride (PMA), affording electron donor–acceptor conjugates 1 and 2, respectively. In addition, a perylene‐monoimide‐monoanhydride (PMIMA) has been connected to a ZnPc through its imido position to yield the ZnPc‐PMIMA conjugate 10. The three conjugates have been studied for photoinduced electron transfer. For ZnPc‐PMIMA 10, electron transfer occurs upon both ZnPc and PMIMA excitation, giving rise to a long‐lived (340 ps) charge‐separated state. For ZnPc‐PMI 1 and ZnPc‐PMA 2, stabilization of the radical ion pair states by using polar media is necessary. In THF, photoexcitation of either ZnPc or PMI/PMA produces charge‐separated states with lifetimes of 375 and 163 ps, respectively.
Discovery of 3‐Hydroxy‐3‐phenacyloxindole Analogues of Isatin as Potential Monoamine Oxidase Inhibitors
Authors: Tripathi Rati K. P. , Krishnamurthy Sairam , Ayyannan Senthil R. 
Published: November 2015

AbstractA series of 3‐hydroxy‐3‐phenacyloxindole analogues of isatin were designed, synthesized, and evaluated in vitro for their inhibitory activity toward monoamine oxidase (MAO) A and B. Most of the synthesized compounds proved to be potent and selective inhibitors of MAO‐A rather than MAO‐B. 1‐Benzyl‐3‐hydroxy‐3‐(4′‐hydroxyphenacyl)oxindole (compound 18) showed the highest MAO‐A inhibitory activity (IC50: 0.009±0.001 μm, Ki: 3.69±0.003 nm) and good selectivity (selectivity index: 60.44). Kinetic studies revealed that compounds 18 and 16 (1‐benzyl‐3‐hydroxy‐3‐(4′‐bromophenacyl)oxindole) exhibit competitive inhibition against MAO‐A and MAO‐B, respectively. Structure–activity relationship studies suggested that the 3‐hydroxy group is an essential feature for these analogues to exhibit potent MAO‐A inhibitory activity. Computational studies revealed the possible molecular interactions between the inhibitors and MAO isozymes. The computational data obtained are congruent with experimental results. Further studies on the lead inhibitors, including co‐crystallization of inhibitor–MAO complexes and in vivo evaluations, are essential for their development as potential therapeutic agents for the treatment of MAO‐associated neurological disorders.
Identification of HDAC6‐Selective Inhibitors of Low Cancer Cell Cytotoxicity
Authors: Gaisina Irina N. , Tueckmantel Werner , Ugolkov Andrey , Shen Sida , Hoffen Jessica , Dubrovskyi Oleksii , Mazar Andrew , Schoon Renee A. , Billadeau Daniel , Kozikowski Alan P. 
Published: November 2015

AbstractThe histone deacetylases (HDACs) occur in 11 different isoforms, and these enzymes regulate the activity of a large number of proteins involved in cancer initiation and progression. The discovery of isoform‐selective HDAC inhibitors (HDACIs) is desirable, as it is likely that such compounds would avoid some of the undesirable side effects found with the first‐generation inhibitors. A series of HDACIs previously reported by us were found to display some selectivity for HDAC6 and to induce cell‐cycle arrest and apoptosis in pancreatic cancer cells. In the present work, we show that structural modification of these isoxazole‐based inhibitors leads to high potency and selectivity for HDAC6 over HDAC1–3 and HDAC10, while unexpectedly abolishing their ability to block cell growth. Three inhibitors with lower HDAC6 selectivity inhibit the growth of cell lines BxPC3 and L3.6pl, and they only induce apoptosis in L3.6pl cells. We conclude that HDAC6 inhibition alone is insufficient for disruption of cell growth, and that some degree of class 1 HDAC inhibition is required. Moreover, the highly selective HDAC6Is reported herein that are weakly cytotoxic may find use in cancer immune system reactivation.
Structure–Activity Relationship Studies of Amino Acid Substitutions in Radiolabeled Neurotensin Conjugates
Authors: Mascarin Alba , Valverde Ibai E. , Mindt Thomas L. 
Published: November 2015

AbstractRadiolabeled derivatives of the peptide neurotensin (NT) and its binding sequence NT(8–13) have been studied as potential imaging probes and therapeutics for NT‐1‐receptor‐positive cancer. However, a direct comparison of reported NT analogues, even if radiolabeled with the same radionuclide, is difficult because different techniques and models have been used for preclinical evaluations. In an effort to identify a suitable derivative of NT(8–13) for radiotracer development, we herein report a side‐by‐side in vitro comparison of radiometallated NT derivatives bearing some of the most commonly reported amino acid substitutions in their sequence. Performed investigations include cell internalization experiments, determinations of receptor affinity, measurements of the distribution coefficient, and blood serum stability studies. Of the [177Lu]‐1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA)‐labeled examples studied, analogues of NT(8–13) containing a short hydrophilic tetraethylene glycol (PEG4) spacer between the peptide and the radiometal complex, and a minimum number of substitutions of amino acid residues, exhibited the most promising properties in vitro.
Photoinduced Isomerization and Hepatoxicities of Semaxanib, Sunitinib and Related 3‐Substituted Indolin‐2‐ones
Authors: Ngai Mun Hong , So Choon Leng , Sullivan Michael B. , Ho Han Kiat , Chai Christina L. L. 
Published: November 2015

Abstract3‐Substituted indolin‐2‐ones are an important class of compounds that display a wide range of biological activities. Sunitinib is an orally available multiple tyrosine kinase inhibitor that has been approved by the US Food and Drug Administration (FDA) for the treatment of renal cell cancer. Sunitinib and a related compound, semaxanib, exist as thermodynamically stable Z isomers, which photoisomerize to E isomers in solution. In this study, 17 3‐substituted indolin‐2‐ones were synthesized, and the kinetics of their photoisomerization were studied by 1H NMR spectroscopy. The rate constants for photoisomerization ranged from 0.009 to 0.048 h−1. Selected compounds were tested for cytotoxicity in the TAMH liver cell line. E/Z mixtures of four compounds were also assessed for toxicity in the TAMH and HepG2 cell lines. In some cases, the stereochemically pure drug was more toxic than the E/Z mixtures, but a general statement cannot be made. Our studies show that each stereoisomer could contribute differently to toxicity, suggesting that stereochemical purity issues that could arise from isomerization cannot be ignored.
Improved Electrochemical Performance of a ZnFe2O4 Nanoflake‐Based Supercapacitor Electrode by Using Thiocyanate‐Functionalized Ionic Liquid Electrolytes
Authors: Vadiyar Madagonda M. , Patil Sandip K. , Bhise Sagar C. , Ghule Anil V. , Han Sung‐Hwan , Kolekar Sanjay S 
Published: November 2015

AbstractThiocyanate‐functionalized ionic liquids (ILs) 1‐butyl‐3‐methylimidazolium thiocyanate [BMIM][SCN], 1‐ethyl‐3‐methylimidazolium thiocyanate [EMIM][SCN], and 3‐methylimidazolium thiocyanate [MIM][SCN], with varying chain lengths, were synthesized by using metathesis followed by ion exchange under reflux conditions. These ILs were investigated for their application as electrolyte with a ZnFe2O4 nanoflake‐based supercapacitor electrode; they exhibited significantly better performance than any other previously reported ILs used as electrolytes. [BMIM][SCN] showed higher specific capacitance (781 F g–1), cycle stability (95 % retention, 3000 cycle), and energy density (156 W h kg–1) than [EMIM][SCN] (590 F g–1, 86 % retention, and 78 W h kg–1) and [MIM][SCN] (250 F g–1, 80 % retention, and 50 W h kg–1). The ZnFe2O4 nanoflake electrodes were able to deliver an energy density of 156 W h kg–1 even at an extra high power density of 7.11 kW kg–1 in [BMIM][SCN] electrolyte, justifying its utility as a potential electrolyte. Furthermore, the effect of how the hydrated ions of the ILs in aqueous media influence the overall performance of the supercapacitor was studied systematically and found to be contrary to the reported trend and use of pure ILs as electrolytes.
Synthesis of the Spiroketal Core of the Pinnatifinoside Family of Natural Products
Authors: Chorley Daniel F. , Furkert Daniel P. , Brimble Margaret A. 
Published: November 2015

AbstractSynthesis of the benzannulated spiroketal core of the pinnatifinoside family of natural products, via Sonagashira cross‐coupling and gold‐catalysed spirocyclisation of functionalised flavone derivatives is described. These investigations lay the framework for ongoing synthetic studies towards the pinnatifinoside family, and related biologically active derivatives.
Linear and Branched Pyridyl–Oxazole Oligomers: Synthesis and Circular Dichroism Detectable Effect on c‐Myc G‐Quadruplex Helicity
Authors: Rizeq Natalia , Georgiades Savvas N. 
Published: November 2015

AbstractFive unprecedented pyridyl–oxazole oligomers exhibiting either linear or branched connectivity of their subunits were developed as a family of potential G‐quadruplex‐interacting ligands. Our synthesis employed variations of a key Pd/Cu‐mediated C–C cross‐coupling/C–H activation reaction to gain access to the oligomer products from a small set of substituted pyridine building blocks. The effect of the compounds on the conformation of a c‐myc oncogene promoter G‐quadruplex was investigated by circular dichroism under various conditions. Some or all of the compounds induced detectable helicity enhancement in low‐cation and Na+‐rich Tris‐HCl (pH 7.4) buffers, respectively, in which the helix was only partially prefolded.
Synthesis of Functionalized Ring C of Escobarines
Authors: Lechuga‐Eduardo Harim , Romero‐Ortega Moises , Olivo Horacio F. 
Published: November 2015

AbstractA synthetic strategy was developed for the preparation of α‐ethynyl‐α,β‐epoxy‐β‐formyl‐ and α‐ethynyl‐α,β‐epoxy‐β‐(hydroxymethyl)cyclohexanone from cyclohexenone as a model study in a proposed synthesis of escobarines. This highly functionalized ring is found in the anti‐TB cassane‐type diterpenes escobarines A and B. Introduction of the β‐hydroxymethyl group was carried out by reversing the chemical reactivity of the enone using the anion of a sulfonyl group and electrophilic attack of paraformaldehyde. Further functionalization of the β‐(hydroxymethyl)cyclohexenone delivered the desired compounds.
Impact of lifestyle‐related disease on conversion and reversion in patients with mild cognitive impairment: after 12 months of follow‐up
Authors: Osone Akira , Arai Reiko , Hakamada Rina , Shimoda Kazutaka 
Published: November 2015

ObjectiveThe objective of the study is to investigate whether the lifestyle‐related disease (LSRD) hypertension, type II diabetes mellitus, and lipid abnormality are associated with conversion and reversion in patients with mild cognitive impairment (MCI) over 12 months of follow‐up.MethodsOne hundred and thirteen patients with MCI were prospectively enrolled and longitudinally assessed. Methods used include mini‐mental state examination, the Japanese version of the cognitive subscale of the Alzheimer's Disease Assessment Scale, the Clinical Dementia Rating, the Frontal Assessment Battery, the Neuropsychiatric Inventory, magnetic resonance imaging, and quantitative single‐photon emission computed tomography. In addition, laboratory examinations of glucose and lipids were also performed. All measurements were performed at first intake and again at the end of the 12‐month follow‐up. Conversion was identified as a change in Clinical Dementia Rating from 0.5 to 1 and reversion as a change from 0.5 to 0.ResultsPatients with MCI with reversion had lower comorbid lipid abnormality at baseline and higher cognitive and behaviour function across the 12‐month follow‐up compared with those with no change or conversion. Patients without comorbid LSRD had lower systolic pressure and lower glucose and triglyceride levels at baseline, as well as less cognitive decline compared with other groups across the follow‐up period.ConclusionsThe absence of lipid abnormality at baseline may contribute to reversion in patients with MCI. The presence of multiple LSRD was associated with cognitive decline. Our results highlight the contribution of multiple LSRD on increasing conversion and decreasing reversion in patients with MCI. Copyright © 2015 John Wiley & Sons, Ltd.