Chemistry Commons^™

Electrospun Nylon 6,6 Nanofibers Functionalized With Β-Cyclodextrin As Solid Phase Extraction Sorbent For Determination Of Parabens, Tassanee Kuakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this study, electrospun nanofibers of nylon 6,6 functionalized with β-cyclodextrin (nylon 6,6/β-CD) were fabricated and applied as a sorbent in solid-phase extraction (SPE) for determination of parabens in water. The electrospinning parameters such as polymer concentration, nylon 6,6/β-CD ratio, and electric field strength were investigated in order to obtain uniform nanofibers. The morphology and physical properties of obtained fibers were characterized by scanning electron microscope (SEM), Fourier transforms infrared spectroscopy (FTIR), and BET surface area analysis. The electrospun nylon 6,6/β-CD nanofibers were achieved with diameter in the range of 120 - 150 nm. The additional of β-CD slightly increased …

High Magnification Polymeric Lens For Smartphone Microscope, Wisansaya Jaikeandee

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, we present a facile method for fabrication of plano-convex lenses, using high reflective optical polymer (Polydimethylsiloxane, Sylgard 184 by Dow Corning, n ~1.42 and Norland Optical adhesive 61, NOA61 by Norland Products, ~1.56) under the confined sessile drop technique. The confined sessile drop technique is a facile method and an adjustable lens geometry through controlled the weight of liquid polymer on the lens substrate, as PMMA circular disk and Sylgard circular disk, with different diameter (2.5-6.0 mm). The liquid polymer was gradually spread and radially over the surface of the lens substrate, and resistance to spreading of …

Exploring The Molecular Origin Of Jet Fuel Thermal Oxidative Deposition Through Statistical Analysis Of Mass Spectral Data And Pyrolysis Gas Chromatography/Mass Spectrometry Of Deposits, Krege Matthew Christison

University of the Pacific Theses and Dissertations

ASTM D3241 (Standard Test Method for Thermal Oxidation Stability of Aviation Turbine Fuels) measures the thermal oxidative stability of jet fuels under elevated temperature and pressure conditions. When jet fuels fail ASTM D3241, either at the refinery or in the distribution system, there can be supply disruptions and financial losses. Understanding the causes of poor thermal oxidative stability in jet fuels could help prevent or mitigate issues. In order to develop a deeper understanding of the molecular precursors that lead to ASTM D3241 failures, a number of analytical methodologies and data treatment techniques have been developed, applied, and reported here. …

Metallic Systems At The Nano And Micro Scale: Bimetallic Nanoparticles As Catalysts And Mcraly Bond Coats In Thermal Barrier Coatings, Kenneth Kane

Theses and Dissertations

The dissertation is split into two parts. The first part will be focused on changes in material properties found at the nanoscale, as miscibility and electronic structure can change significantly with size. The formation of classically-immiscible bimetallic nanoparticles (BNPs) becomes favorable at the nanoscale and novel catalytic properties can emerge from the bimetallic alloying. The formation of alloyed and non-alloyed BNPs is achieved through pulse laser ablation (PLA) and a significant increase in catalytic activity is observed for both. Recently discovered, the increased activity in the non-alloyed BNPs, deemed multicomponent photocatalysis, is examined and the proposed mechanism discussed. The second …

Development And Characterization Of Stationary Phase Gradients For High Performance Liquid Chromatography, Anna Forzano

Theses and Dissertations

Choosing a stationary phase is the first step in developing a liquid chromatography (LC) separation method, where the selectivity is governed by the differential interactions of the analytes with the stationary and mobile phases. Introducing a gradient in stationary phase functionality allows for tuning of analyte retention, translating to a possible improvement in selectivity and an increase in resolution versus that offered by uniform stationary phases.

In this work, C₁₈-silica, phenylbutyl-silica, and phenylbutyl-ammonium opposed continuous stationary phase gradients were fabricated using controlled rate infusion (CRI) on particle packed LC columns. Characterization of the stationary phase was carried out …

Non-Covalent And Covalent Interactions Between Phenylacetylene And Quinoline Radical Cations With Polar And Non-Polar Molecules In The Gas Phase, Adam C. Pearcy

Theses and Dissertations

Gas phase molecular clusters present an ideal medium for observing factors that drive chemical reactions without outside interferences from excessive solvent molecules. Introducing an ion into the cluster promotes ion-molecule interactions that may manifest in a variety of non-covalent or even covalent binding motifs and are of significant importance in many fields including atmospheric and astronomical sciences. For instance, in outer space, molecules are subject to ionizing radiation where ion-molecule reactions become increasingly competitive to molecule-molecule interactions. To elucidate individual ion-molecule interaction information, mass spectrometry was used in conjunction with appropriate theoretical calculations.

Three main categories of experiment were conducted …

Metal Nanoparticle Synthesis By Photochemical Reduction With A High-Intensity Focused Laser Beam, Victoria K. Meader

Theses and Dissertations

Colloidal, metallic nanoparticles have myriad applications, but they are most ideal when they are monodisperse, and demonstrate maximum catalytic utility when they are small (< 5 nm) and uncoated; because their surface area is accessible and maximized. Laser- assisted metal nanoparticle synthesis is a ‘green’ method that has become a topic of active research because it is able to produce uncoated or ‘naked’ products. The nanoparticles synthesized in this work were formed through the reduction of metal salts in aqueous solutions; but the reducing agent is an electron-dense microplasma generated by the laser pulse interacting with the media. Because no chemical reducing agents or stabilizers are needed, the products have no surfactants.

The underlying reaction mechanisms that drive this type of synthesis are generally understood, however, there is insufficient detail that would allow control over the formation of ultimate product morphologies and size distributions. The metals examined in this thesis are: gold, whose formation follows an autocatalytic rate law; and silver, whose formation follows a first-order rate law. Through my research, I was able to …

2nd Tier Assay For The Detection Of Congenital Adrenal Hyperplasia By Virginia’S Newborn Screening Laboratory: Steroid Profile By Hplc-Ms/Ms, Christopher E. Nixon

Theses and Dissertations

Congenital Adrenal Hyperplasia (CAH) encompasses several disorders related to disruptions in the adrenal steroid production pathway. These disruptions may cause virilization of the external female sex organs, incorrect gender assignment, precocious puberty, and in the most severe form, may cause life-threatening salt wasting and adrenal crisis if not detected and treated early in the newborn period.

17α-Hydroxyprogesterone (17-OHP) is the primary target for immunofluorescence detection of CAH from dried blood spots in newborn screening (NBS). Unfortunately, current immunoassay techniques for the detection of CAH suffer from high false positive rates. The primary factors contributing to false positive determinations can include …

Adhesion At Solid/Liquid Interfaces, Neda Ojaghlou

Theses and Dissertations

The adhesion at solid/liquid interface plays a fundamental role in diverse fields and helps explain the structure and physical properties of interfaces, at the atomic scale, for example in catalysis, crystal growth, lubrication, electrochemistry, colloidal system, and in many biological reactions. Unraveling the atomic structure at the solid/liquid interface is, therefore, one of the major challenges facing the surface science today to understand the physical processes in the phenomena such as surface coating, self-cleaning, and oil recovery applications. In this thesis, a variety of theory/computational methods in statistical physics and statistical mechanics are used to improve understanding of water adhesion …

Non-Target Analyses Of Novel Psychoactive Substances; Inherent Variation In Gcms Relative Abundances And Gas Phase Hydrogen Deuterium Exchange Isomer Discrimination, Kristin Michelle Kelly

Graduate Theses, Dissertations, and Problem Reports (ETD)

Novel psychoactive substances (NPSs) are synthetically derived compounds designed to mimic the effects of other illicit drugs. An endless cycle of NPSs continually reach the drug market due to limitations in drug legislation creating two problems: (1) non-availability of standards and (2) multiple isobars indistinguishable even to high resolution mass spectrometry. Gas chromatography-mass spectrometry (GCMS) is the most common instrument used for compound identification in non-targeted seized drug analysis. Compound identification using this technique relies on mass spectra where the percent relative abundances (%RAs) of all m/z values are compared manually or searched against a library database. Lacking standards, laboratories …

Copper-Catalyzed Regioselective Boracarboxylation Of Vinyl Arenes: Catalytic Efficiency And Synthetic Utility, Trina M. Perrone

Graduate Theses, Dissertations, and Problem Reports (ETD)

Hetero(element) carboxylation is an appealing transformation that involves the installation of CO2 and another hetero(element) in one step. This transition metal-catalyzed one-pot synthesis provides a route to achieve highly functionalized carboxylic acid products with an abundant and cheap C1 feedstock. This difunctionalization also avoids the use of reactive metal hydride species, which is a prominent limitation of hydrocarboxylation chemistry. A copper-catalyzed regioselective boracarboxylation of vinyl arenes has been developed to access pharmaceutically relevant β-boryl-α-aryl propionic acid products. One drawback of this reaction is the necessity for high catalyst loading to achieve catalytic turnover. To circumvent this issue, the reduction of …

Thermostable Phytase In Feed And Fuel Industries, Ushasree Mrudula Vasudevan, Amit Jaiswal, Shyam Krishna, Ashok Pandey

Articles

Phytase with wide ranging biochemical properties has long been utilized in a multitude of industries, even so, thermostability plays a crucial factor in choosing the right phytase in a few of the sectors. Mesophilic phytases are not considered to be a viable option in the feed industry owing to its limited stability in the required feed processing temperature. In the recent past, inclusion of thermostable phytase in fuel ethanol production from starch based raw material has been demonstrated with economic benefits. Therefore, considerable emphasis has been placed on using complementary approaches such as mining of extremophilic microbial wealth, encapsulation and …

Electrochemical Detection Of Fentanyl Using Screen-Printed Carbon Electrodes With Confirmatory Analysis Of Fentanyl And Its Analogs In Oral Fluid Using Liquid Chromatography-Tandem Mass Spectrometry, Colby E. Ott

Graduate Theses, Dissertations, and Problem Reports (ETD)

Utilizing screen-printed carbon electrodes (SPCEs), a fast, simple, and sensitive approach toward the detection, identification, and quasi-quantitation of fentanyl was achieved both in an electrochemical cell and as a drop on the electrode surface. Electro-oxidation of fentanyl at the electrode was demonstrated using adsorptive stripping square-wave voltammetry between -0.5 V and +1.6 V with 100 mM Tris-HCl buffer at pH 8.5 as supporting electrolyte. Parameter optimization was conducted during method development to include supporting electrolyte and pH, electrochemical technique, pre-treatment and equilibration time, and various surface modifications. The simplest method utilizing an unmodified SPCE was determined to be appropriate for …

Improving Extraction Processes Of Crustacean Chitin Using Solid State Analytical Techniques, Fionn O'Fearghail, Michelle Giltrap, Christine O'Connor, Patrice Behan

Articles

Solid state analytical techniques are becoming more widely used for the analysis of a range of organic products which demonstrate very poor solubility in both common organic and polar solvents and as such cannot be accurately characterised using solution based techniques. Primarily used as a secondary technique for qualitative analysis of insoluble intermediates and products in organic synthesis, 13C CP-MAS NMR can be utilised in tandem with a targeted extraction and clean up procedure for accurate quantitative analysis of insoluble bio-molecules of interest. Here solid state 13C CP-MAS NMR is utilised as the primary analytical technique in the characterisation of …

Investigation Of Coastal Sea-Fog Formation Using The Wibs (Wide Band Integrated Bioaerosol Sensor) Technique, Shane M. Daly, David O'Connor, David A. Healy, Stig Hellebust, Jovanna Arndt, Eoinj. Mcgillicuddy, Patrick Feeney, Michael Quirke, John C. Wenger, John R. Sodeau

Articles

Abstract. A wideband integrated bioaerosol sensor (WIBS4) was deployed in Haulbowline Island, Cork Harbour, to detect fluorescence particles in real time during July and September 2011. A scanning mobility particle sizer (SMPS) was also installed providing sizing analysis of the particles over the 10–450nm range. During the campaign, multiple fog formation events occurred; they coincided with dramatic increases in the recorded fluorescent particle counts. The WIBS sizing and fluorescence intensity profiles indicated that the origin of the signals was potentially non-biological in nature (i.e. PBAPs, primary biological aerosol particles). Furthermore, the data did not support the presence of known fluorescing …

Construction Of Trisubstituted Chromone Skeletons Carrying Electron-Withdrawing Groups Via Phio-Mediated Dehydrogenation And Its Application To The Synthesis Of Frutinone A, Qiao Li, Chen Zhuang, Donghua Wang, Wei Zhang, Rongxuan Jia, Fengxia Sun, Yilin Zhang, Yunfei Du

Faculty & Staff Scholarship

Abstract

The construction of the biologically interesting chromone skeleton was realized by PhIO-mediated dehydrogenation of chromanones under mild conditions. Interestingly, this method also found application in the synthesis of the naturally occurring frutinone A.

Effect Of Bulk Composition On The Heterogeneous Oxidation Of Semi-Solid Atmospheric Aerosols, Hanyu Fan, Fabien Goulay

Faculty & Staff Scholarship

Abstract: The OH-initiated heterogeneous oxidation of semi-solid saccharide particles with varying bulk compositions was investigated in an atmospheric pressure flow tube at 30% relative humidity. Reactive uptake coefficients were determined from the rate loss of the saccharide reactants measured by mass spectrometry at different monosaccharide (methyl-β-d-glucopyranoside, C7H14O6) and disaccharide (lactose, C12H22O11) molar ratios. The reactive uptake for the monosaccharide was found to decrease from 0.53 ± 0.10 to 0.05 ± 0.06 as the mono-to-disaccharide molar ratio changed from 8:1 to 1:1. A reaction–diffusion model was developed in order to determine the effect of chemical composition on the reactive uptake. The …

In Situ Infrared Spectroscopic Study Of Iron-Catalyzed Hydromagnesiation Of Vinyl Arenes, Jessica Ann Rogers

Graduate Theses, Dissertations, and Problem Reports (ETD)

Iron catalysis, especially homogeneous catalysis, has been a resurging topic of organometallic chemistry research. Discussions of past and present mechanistic analyses for homogeneous iron catalysis will be discussed in Chapter 1. As an expansion of homogeneous iron catalysis, in situ infrared spectroscopy will be used to develop a full mechanistic study of iron-catalyzed hydromagnesiation of vinyl arenes. The kinetic analyses by both initial and observed rate measurements indicate complex concentration dependencies on the (PDI)iron catalyst as well as sacrificial Grignard reagent and styrene. These complexities are not limited to non-linear catalyst and Grignard initial rate and inhibition by styrene/Grignard at …

Mwcnts-Fe$_{2}$O$_{3}$ Nanoparticle Nanohybrid-Based Highly Sensitive Electrochemical Sensor For The Detection Of Kaempferol In Broccoli Samples, Nomnotho Jiyane, Myalowenkosi I. Sabela, Suvardhan Kanchi, Phumlane S. Mdluli, Mavis Xhakaza, Olayide A. Arodola, Krishna Bisetty

Turkish Journal of Chemistry

This work reports an electrochemical sensor with a modified glassy carbon electrode for the detection of kaempferol. The method was tailored by the immobilization of multiwalled carbon nanotubes (MWCNTs) assimilated with Fe$_{2}$O$_{3}$ nanoparticles (NPs) onto the electrode surface to detect kaempferol using differential pulse voltammetry. Thermogravimetric, transmission electron microscopic, cyclic, and differential voltammetric techniques were employed to characterize the developed electrochemical sensor. The kaempferol produces an anodic quasireversible peak at pH 6.6 in phosphate buffer with Fe$_{2}$O$_{3}$NPs/MWCNTs/GCE. The current of the anodic peak at 0.32 V increases linearly upon addition of kaempferol standard, resulting in Ip($\mu $A) = 1.577($\mu $M) …

Extraction Of High-Purity Silica From Rice Husk Via Hydrochloric Acid Leaching Treatment, Seitkhan Azat, Zhanar Sartova, Kalampyr Bekseitova, Kydyr Askaruly

Turkish Journal of Chemistry

The present paper aimed at the investigation of the effect of preliminary acid treatment on the structure and purity of extracted silica. In this study, the acid leaching of rice husk (RH) in 2 M hydrochloric acid solution before the calcination process at 600 $^{\circ}$C was proposed to achieve completely white silica with high specific surface area and low content of impurities. RH, selected from the Almaty Region, Kyzylorda Region, and Turkestan Region was used as the main silica source. The results confirmed that the highest purity (98.2%-99.7%) amorphous silica with a specific surface area between 120 and 980 m$^{2}$ …

Magnetic Solid-Phase Extraction Based On Coriolus Versicolor-Immobilized $\Gamma $-Fe$_{2}$O$_{3}$ Nanoparticles For Preconcentration And Determination Of Al(Iii) In Water And Food Samples, Sadi̇n Özdemi̇r, Mustafa Serkan Yalçin, Ersi̇n Kilinç, Mustafa Soylak

Turkish Journal of Chemistry

A method for preconcentration of Al(III) prior to its determination by inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed because the sensitivity of ICP-OES is insufficient for trace-level measurement of Al(III). The method is based on the use of Coriolus versicolor}-immobilized $\gamma $-Fe$_{2}$O$_{3}$ magnetic nanoparticles as a solid phase sorbent. The best experimental conditions were found as pH 6.0, 2.0 mL/min flow rate, 100 mg amount of C. versicoloron 150 mg of $\gamma $-Fe$_{2}$O$_{3}$ nanoparticles, and 500 mL of sample volume. The Al(III) absorbed on biosorbent was eluted with 5.0 mL of 1.0 mol/L HCl. Limit of detection, limit of …

Design, Synthesis, Biological Evaluation And Molecular Docking Of Novel Molecules To Parp-1 Enzyme, Fati̇h Tok, Bedi̇a Kaymakçioğlu, Recep İlhan, Si̇nem Yilmaz, Petek Ballar Kirmizibayrak, Tuğba Taşkin Tok

Turkish Journal of Chemistry

Poly (ADP-ribose) polymerase (PARP) enzyme catalyzes the transfer of ADP-ribose into target proteins. Therefore, PARP is responsible for DNA repair, cell proliferation, and cell death. In this study, potential PARP enzyme inhibitors were designed and synthesized. The synthesized compounds were elucidated by Fourier-transform infrared spectroscopy, $^{1}$H NMR, $^{13}$C NMR, heteronuclear single-quantum correlation, and mass spectrometry, and their purity was checked via thin-layer chromatography, high-performance liquid chromatography, and elemental analysis. A total of 63 newly synthesized compounds were screened in terms of PARP inhibition by cellular PARylation assay in the HeLa cell line. It was found that 19 compounds significantly inhibited …

The Effect Of Starting Material Types On The Structure Of Graphene Oxide And Graphene, Fi̇li̇z Boran, Sevi̇l Çeti̇nkaya Gürer

Turkish Journal of Chemistry

In this study, the effects of starting material types on graphene oxide (GO) are reported with the aim of developing graphene (GR) synthesis. The GOs were prepared from natural graphite (NG) powder and graphite nanoplate (GNp) based on the Hummers method. Two kinds of GR were successfully synthesized using GOs, which were prepared from NG and GNp in the presence of hydrazine and ammonia for 24 h at a 100 $^{\circ}$C reaction temperature. The synthesized GOs and GRs were characterized by X-ray diffraction (XRD) techniques, Fourier transform infrared, high-contrast transmission electron microscopy (HCTEM), dispersive Raman spectroscopic analyses, and elemental analyses. …

Density Functional Theory-Supported Studies Of Structural And Electronic Properties Of Substituted-Phenol Derivatives Synthesized By Efficient O- Or C-Arylation Via Chan--Lam Or Suzuki Cross-Coupling Reactions, Hafiz Mansoor Ikram, Nasir Rasool, Muhammad Ali Hashmi, Muhammad Arfan Anjum, Kulsoom Ghulam Ali, Muhammad Zubair, Gulraiz Ahmad, Tariq Mahmood

Turkish Journal of Chemistry

The present study reports the efficient synthesis and computational studies of the structural and electronic properties of some interesting substituted phenol derivatives. Efficient and versatile procedures to synthesize a series of diaryl ether derivatives (2a-2c, 4a-4h) and bis-arylated products (5a-5c) are described. In this manuscript, using the commercially available starting material 1 and 3, a 1-step approach was developed by means of Cu(II)-mediated Chan-Lam and Pd-catalyzed Suzuki cross-coupling reactions to synthesize diaryl ether and bis-arylated products with moderate to good yields. The starting substrates, 2-bromo-4-methylphenol 1 or 2,4-dibromophenol 3, were both treated with several arylboronic acids, which led to the …

In Silico And In Vitro Evaluation Of The Biological Activity Of Some Organic Sulfur-Containing Compounds, Victoria Osipova, Maria Polovinkina, Anastasia Osipova, Yulia Gracheva, Andrey Okhlobystin

Turkish Journal of Chemistry

It was predicted, using the Prediction of Activity Spectra for Substances online software, that organic sulfur-containing compounds 2,6-di-tert-butyl-4-mercaptophenol (1), 2,6-di-tert-butyl-4-(3-mercaptopropyl)phenol (2), bis-3-[3,5-di-tert-butyl-4-hydroxyphenyl)propyl] sulfide (3), bis(3,5-di-tert- butyl-4-hydroxyphenyl) disulfide (4), diphenyl disulfide (5), dibenzyl disulfide (6), dibutyl disulfide (7), di-tert-butyl disulfide (8), diallyl disulfide (9), and methyl propyl trisulfide (10) could possess antioxidant activity and act as active scavengers of oxygen metabolites. The antiradical activity of these species was analyzed and it was shown that they were able to react with electrochemically generated the superoxide anion radical. The rate constants for reactions of 1-10 with the superoxide anion radical were calculated. The …

Acetylene-Bridged Triazine Π-Conjugated Structures: Synthesis And Liquid Crystalline Properties, Ni̇hat Akkurt, Mohammed Hadi Ali Al-Jumaili, Belkiz Bi̇lgi̇n Eran, Hale Ocak, Lokman Torun

Turkish Journal of Chemistry

We report the synthesis and liquid crystalline properties of a new type of tribranched compound built up from triazine as the central core and electron-rich triazine rings as peripheral groups. An equimolar mixture of the star-shaped compound based on the 1,3,5-triazine core with 4-dodecyloxybenzoic acid produced an organic salt exhibiting a columnar mesophase with a dendritic growing texture at low temperatures. The liquid crystalline properties of the triazine-based compound and organic salt were investigated by differential scanning calorimetry and polarizing optical microscopy.

The Promoted Synthesis Of Minoxidil By Magnetic Nanoparticles Of Cobalt Ferrite (Cofe$_{2}$O$_4$) As A Heterogeneous Reusable Catalyst, Ronak Eisavi, Fateme Ahmadi, Behzad Zeynizadeh, Mehri Kouhkan

Turkish Journal of Chemistry

Minoxidil (2,4-diamino-6-piperidinopyrimidine 3-oxide) was primarily recognized as a drug for reducing vascular resistance to blood flow. It was later introduced as a more important medicine for topical stimulation of hair growth and baldness reverting as well as treatment of androgenic alopecia through increasing prostaglandin endoperoxide synthesis. In this study, magnetic nanoparticles (MNPs) of spinel ferrites (MFe$_{2}$O$_{4}$, M = Co, Ni, Fe, Cu, and Zn) via solid-state grinding procedure were prepared and then characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, and Fourier transform infrared techniques. The prepared nanoferrites were utilized as efficient and green heterogeneous …

Synthesis And Characterization Of Novel Indanone-Based Spiro-Dihydrobenzofuran Derivatives, Meli̇ha Burcu Gürdere, Neşe Dürü, Yakup Budak, Mustafa Ceylan

Turkish Journal of Chemistry

In this study, the synthesis and characterization of novel indanone-based spiro-dihydrobenzofuran derivatives were examined. Firstly, chalcone-like compounds 4a-k, ($E)$-2-benzylidene-2,3-dihydro-1$H$-inden-1-one derivatives, were synthesized by the base-catalyzed addition of benzaldehyde derivatives to 2,3-dihydro-1$H$-inden-1-one. Then Mn(OAc)$_{3}$-mediated addition of dimedone (2) to the chalcone-like compounds gave two novel spiro-dihydrobenzofuran isomers: (3$S)$-6,6-dimethyl-3-aryl-6,7-dihydro-3$H$-spiro [benzofuran-2,2'-indene]-1',4(3'$H$,5$H)$-dione (5a-k) and (2'$S)$-6,6-dimethyl-2-aryl-6,7-dihydro-2$H$-spiro[benzofuran-3,2'-indene]-1',4(3'$H$,5$H)$-dione (6a-k) in good yields. The isomers were separated by column chromatography and their structures were elucidated on the basis of spectral data (NMR, IR) and elemental analysis.

Electrochemical Responses Of Flexible Graphite In H$_2$So$_4$, Mehmet Suha Yazici

Turkish Journal of Chemistry

Asymmetric capacitors are gaining attention due to their hybrid nature with higher power and energy density compared to individual batteries or capacitors. Electrochemical and structural characteristics of flexible graphite in 40% H$_{2}$SO$_{4\, }$electrolyte are investigated using electrochemical and microscopy techniques. There is a correlation between intercalation of electrolyte and the enlargement of interlayer spacing and electrochemical response. Conditions favoring planar orientation are electrochemically less active and more stable in such corrosive electrolytes. There are response variations between plain and resin-impregnated flexible graphite samples. The reaction peak seems to be reversible for resin impregnated samples while plain samples show continuous intercalation. …

Natural Diterpenoid Alysine A Isolated From Teucrium Alyssifolium Exerts Antidiabetic Effect Via Enhanced Glucose Uptake And Suppressed Glucose Absorption, Alaatti̇n Şen, Buket Ayar, Anil Yilmaz, Özden Özgün Acar, Gurbet Çeli̇k Turgut, Gülaçti Topçu

Turkish Journal of Chemistry

Teucrium species have been used in folk medicine as antidiabetic, antiinflammatory, antiulcer, and antibacterial agents. We have explored in vitro antidiabetic impacts of 2 natural diterpenoids, alysine A and alysine B, isolated from Teucrium alyssifolium. The lactate dehydrogenase (LDH) cytotoxicity assay, glucose uptake test, glucose utilization (glycogen content) test, glucose transport test, glucose absorption ($\alpha $-glucosidase activity) test, insulin secretion test, RNA isolation and cDNA synthesis assay, qPCR quantification assays, and statistical analyses were carried out in the present study. Alysine A exerted the following effects at non-cytotoxic doses: . Enhanced the glucose uptake, as much as the insulin in …