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  • 1.
    Appadurai, Tamilselvan
    et al.
    Univ Madras, Natl Ctr Nanosci & Nanotechnol, Guindy Campus, Chennai 600025, Tamil Nadu, India..
    Subramaniyam, Chandrasekar M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Kuppusamy, Rajesh
    Univ Madras, Dept Phys Chem, Guindy Campus, Chennai 600025, Tamil Nadu, India..
    Karazhanov, Smagul
    Inst Energy Technol IFE, Dept Solar Energy, N-2027 Kjeller, Norway..
    Subramanian, Balakumar
    Univ Madras, Natl Ctr Nanosci & Nanotechnol, Guindy Campus, Chennai 600025, Tamil Nadu, India..
    Electrochemical Performance of Nitrogen-Doped TiO2 Nanotubes as Electrode Material for Supercapacitor and Li-Ion Battery2019Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, nr 16, artikel-id 2952Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electrochemical anodized titanium dioxide (TiO2) nanotubes are of immense significance as electrochemical energy storage devices owing to their fast electron transfer by reducing the diffusion path and paving way to fabricating binder-free and carbon-free electrodes. Besides these advantages, when nitrogen is doped into its lattice, doubles its electrochemical activity due to enhanced charge transfer induced by oxygen vacancy. Herein, we synthesized nitrogen-doped TiO2 (N-TiO2) and studied its electrochemical performances in supercapacitor and as anode for a lithium-ion battery (LIB). Nitrogen doping into TiO2 was confirmed by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) techniques. The electrochemical performance of N-TiO2 nanotubes was outstanding with a specific capacitance of 835 mu F cm(-2) at 100 mV s(-1) scan rate as a supercapacitor electrode, and it delivered an areal discharge capacity of 975 mu A h cm(-2) as an anode material for LIB which is far superior to bare TiO2 nanotubes (505 mu F cm(-2) and 86 mu A h cm(-2), respectively). This tailor-made nitrogen-doped nanostructured electrode offers great promise as next-generation energy storage electrode material.

  • 2. Bednarska, Joanna
    et al.
    Zalesny, Robert
    Tian, Guangjun
    Natarajan Arul, Murugan
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Bartkowiak, Wojciech
    Nonempirical Simulations of Inhomogeneous Broadening of Electronic Transitions in Solution: Predicting Band Shapes in One- and Two-Photon Absorption Spectra of Chalcones2017Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 22, nr 10, artikel-id 1643Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have examined several approaches relying on the Polarizable Embedding (PE) scheme to predict optical band shapes for two chalcone molecules in methanol solution. The PE-TDDFT and PERI-CC2 methods were combined with molecular dynamics simulations, where the solute geometry was kept either as rigid, flexible or partly-flexible (restrained) body. The first approach, termed RBMD-PE-TDDFT, was employed to estimate the inhomogeneous broadening for subsequent convolution with the vibrationally-resolved spectra of the molecule in solution determined quantum-mechanically (QM). As demonstrated, the RBMD-PE-TDDFT/QM-PCM approach delivers accurate band widths, also reproducing their correct asymmetric shapes. Further refinement can be obtained by the estimation of the inhomogeneous broadening using the RBMD-PERI-CC2 method. On the other hand, the remaining two approaches (FBMD-PE-TDDFT and ResBMD-PE-TDDFT), which lack quantum-mechanical treatment of molecular vibrations, lead to underestimated band widths. In this study, we also proposed a simple strategy regarding the rapid selection of the exchange-correlation functional for the simulations of vibrationally-resolved one-and two-photon absorption spectra based on two easy-to-compute metrics.

  • 3. Diaz-Alvarez, Alba E.
    et al.
    Mesas-Sanchez, Laura
    Dinér, Peter
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi. Uppsala University, Sweden.
    Access to Optically Pure beta-Hydroxy Esters via Non-Enzymatic Kinetic Resolution by a Planar-Chiral DMAP Catalyst2014Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 19, nr 9, s. 14273-14291Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of new approaches to obtain optically pure beta-hydroxy esters is an important area in synthetic organic chemistry since they are precursors of other high value compounds. Herein, the kinetic resolution of racemic beta-hydroxy esters using a planar-chiral DMAP derivative catalyst is presented. Following this procedure, a range of aromatic beta-hydroxy esters was obtained in excellent selectivities (up to s = 107) and high enantiomeric excess (up to 99% ee). Furthermore, the utility of the present method was demonstrated in the synthesis of (S)-3-hydroxy-N-methyl-3-phenylpropanamide, a key intermediate for bioactive molecules such as fluoxetine, tomoxetine or nisoxetine, in its enantiomerically pure form.

  • 4.
    García-Gallego, Sandra
    et al.
    KTH, Skolan för kemivetenskap (CHE).
    Franci, Gianluigi
    Falanga, Annarita
    Gómez, Rafael
    Folliero, Veronica
    Galdiero, Stefania
    de la Mata, Francisco Javier
    Galdiero, Massimiliano
    Function Oriented Molecular Design: Dendrimers as Novel Antimicrobials.2017Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 22, nr 10, artikel-id E1581Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In recent years innovative nanostructures are attracting increasing interest and, among them, dendrimers have shown several fields of application. Dendrimers can be designed and modified in plentiful ways giving rise to hundreds of different molecules with specific characteristics and functionalities. Biomedicine is probably the field where these molecules find extraordinary applicability, and this is probably due to their multi-valency and to the fact that several other chemicals can be coupled to them to obtain desired compounds. In this review we will describe the different production strategies and the tools and technologies for the study of their characteristics. Finally, we provide a panoramic overview of their applications to meet biomedical needs, especially their use as novel antimicrobials.

  • 5.
    Karimiyan, Hanieh
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Univ Mazandaran, Dept Chem, Babol Sar 4741695447, Iran.
    Hadjmohammadi, Mohammad Reza
    Univ Mazandaran, Dept Chem, Babol Sar 4741695447, Iran..
    Laxman, Karthik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Moein, Mohammad Mahdi
    Karolinska Univ Hosp, Dept Radiopharm, S-17176 Stockholm, Sweden..
    Dutta, Joydeep
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Abdel-Rehim, Mohamed
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet, SE-171 76 Stockholm, Sweden.
    Graphene Oxide/Polyethylene Glycol-Stick for Thin Film Microextraction of beta-Blockers from Human Oral Fluid by Liquid Chromatography-Tandem Mass Spectrometry2019Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, nr 20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A wooden stick coated with a novel graphene-based nanocomposite (Graphene oxide/polyethylene glycol (GO/PEG)) is introduced and investigated for its efficacy in solid phase microextraction techniques. The GO/PEG-stick was prepared and subsequently applied for the extraction of beta -blockers, acebutolol, and metoprolol in human oral fluid samples, which were subsequently detected by liquid chromatography tandem mass spectrometry (LC-MS/MS). Experimental parameters affecting the extraction protocol including sample pH, extraction time, desorption time, appropriate desorption solvent, and salt addition were optimized. Method validation for the detection from oral fluid samples was performed following FDA (Food and Drug Administration) guidelines on bioanalytical method validation. Calibration curves ranging from 5.0 to 2000 nmol L-1 for acebutolol and 25.0 to 2000 nmol L-1 for metoprolol were used. The values for the coefficient of determination (R-2) were found to be 0.998 and 0.996 (n = 3) for acebutolol and metoprolol, respectively. The recovery of analytes during extraction was 80.0% for acebutolol and 62.0% for metoprolol, respectively. The limit of detections (LODs) were 1.25, 8.00 nmol L-1 for acebutolol and metoprolol and the lower limit of quantifications (LLOQ) were 5.00 nmol L-1 for acebutolol and 25.0 nmol L-1 for metoprolol. Validation experiments conducted with quality control (QC) samples demonstrated method accuracy between 80.0% to 97.0% for acebutolol and from 95.0% to 109.0% for metoprolol. The inter-day precision for QC samples ranged from 3.6% to 12.9% for acebutolol and 9.5% to 11.3% for metoprolol. Additionally, the GO/PEG-stick was demonstrated to be reusable, with the same stick observed to be viable for more than 10 extractions from oral fluid samples.

  • 6. Klein, Michael
    et al.
    Krainz, Karin
    Redwan, Itedale Namro
    Dinér, Peter
    Grøtli, Morten
    Synthesis of chiral 1,4-disubstituted-1,2,3-triazole derivatives from amino acids2009Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 14, nr 12, s. 5124-Artikel i tidskrift (Refereegranskat)
  • 7.
    Kosina, Pavel
    et al.
    Palacky Univ, Fac Med & Dent, Dept Med Chem & Biochem, Hnevotinska 3, Olomouc 77515, Czech Republic..
    Paloncyova, Marketa
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi. Palacky Univ, Fac Sci, Dept Phys Chem, Reg Ctr Adv Technol & Mat, Tr 17 Listopadu 12, Olomouc 77146, Czech Republic..
    Svobodova, Alena Rajnochova
    Palacky Univ, Fac Med & Dent, Dept Med Chem & Biochem, Hnevotinska 3, Olomouc 77515, Czech Republic..
    Zalesak, Bohumil
    Univ Hosp Olomouc, Dept Plast & Aesthet Surg, IP Pavlova 6, Olomouc 77900, Czech Republic..
    Biedermann, David
    Acad Sci Czech Republ, Inst Microbiol, Lab Biotransformat, Videnska 1083, Prague 14220, Czech Republic..
    Ulrichova, Jitka
    Palacky Univ, Fac Med & Dent, Dept Med Chem & Biochem, Hnevotinska 3, Olomouc 77515, Czech Republic..
    Vostalova, Jitka
    Palacky Univ, Fac Med & Dent, Dept Med Chem & Biochem, Hnevotinska 3, Olomouc 77515, Czech Republic..
    Dermal Delivery of Selected Polyphenols from Silybum marianum. Theoretical and Experimental Study2019Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, nr 1, artikel-id 61Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Silymarin is a well-known standardized extract from the seeds of milk thistle (Silybum marianum L., Asteraceae) with a pleiotropic effect on human health, including skin anticancer potential. Detailed characterization of flavonolignans properties affecting interactions with human skin was of interest. The partition coefficients log P-ow of main constitutive flavonolignans, taxifolin and their respective dehydro derivatives were determined by a High Performance Liquid Chromatography (HPLC) method and by mathematical (in silico) approaches in n-octanol/water and model lipid membranes. These parameters were compared with human skin intake ex vivo. The experimental log P-ow values for individual diastereomers were estimated for the first time. The replacement of n-octanol with model lipid membranes in the theoretical lipophilicity estimation improved the prediction strength. During transdermal transport, all the studied compounds permeated the human skin ex vivo; none of them reached the acceptor liquid. Both experimental/theoretical tools allowed the studied polyphenols to be divided into two groups: low (taxifolin, silychristin, silydianin) vs. high (silybin, dehydrosilybin, isosilybin) lipophilicity and skin intake. In silico predictions can be usefully applied for estimating general lipophilicity trends, such as skin penetration or accumulation predictions. However, the theoretical models cannot yet provide the dermal delivery differences of compounds with very similar physico-chemical properties; e.g., between diastereomers.

  • 8. Kosychova, L.
    et al.
    Karalius, Antanas
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Staniulyte, Z.
    Sirutkaitis, R. A.
    Palaima, A.
    Laurynenas, A.
    Anusevičius, Ž.
    New 1-(3-nitrophenyl)-5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1,5]benzodiazepines: Synthesis and computational study2015Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 20, nr 4, s. 5392-5408Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Triazole derivatives constitute an important group of heterocyclic compounds have have been the subject of extensive study in the recent past. These compounds have shown a wide range of biological and pharmacological activities. In this work, new fused tricyclic 1-(3-nitrophenyl)-5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1,5]-benzodiazepines have been synthesized by the thermal cyclization of N′-(2,3-dihydro-1H-1,5-benzodiazepin-4-yl)-3-nitrobenzohydrazides. After screening ethanol, toluene and 1-butanol as solvents, butanol-1 was found to be the best choice for the cyclization reaction in order to obtain the highest yields of tricyclic derivatives. The chemical structures of the synthesized compounds were elucidated by the analysis of their IR, 1H- and 13C-NMR spectral data. For tentative rationalization of the reaction processes, the global and local reactivity indices of certain compounds, taking part in the reaction pathway, were assessed by means of quantum mechanical calculations using the conceptual density functional theory (DFT) approach. This work could be useful for the synthesis of new heterocyclic compounds bearing a fused triazole ring.

  • 9.
    Liu, Min
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. University of Science and Technology Beijing, National Center for Materials Service Safety.
    Jin, Ying
    University of Science and Technology Beijing, National Center for Materials Service Safety.
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Co-adsorption of H2O, OH, and Cl on aluminum and intermetallic surfaces and its effects on the work function studied by DFT calculations2019Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049Artikel i tidskrift (Refereegranskat)
  • 10.
    Moein, Mohammad Mahdi
    et al.
    Karolinska Univ Hosp, Dept Radiopharm, S-17176 Stockholm, Sweden..
    Abdel-Rehim, Abbi
    Univ Manchester, Fac Sci & Engn, Manchester M13 9PL, Lancs, England..
    Abdel-Rehim, Mohamed
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Karolinska Inst, Karolinska Hosp, Ctr Psychiat Res, Dept Clin Neurosci, S-17176 Stockholm, Sweden..
    Recent Applications of Molecularly Imprinted Sol-Gel Methodology in Sample Preparation2019Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, nr 16, artikel-id 2889Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Due to their selectivity and chemical stability, molecularly imprinted polymers have attracted great interest in sample preparation. Imprinted polymers have been applied for the extraction and the enrichment of different sorts of trace analytes in biological and environmental samples before their analysis. Additionally, MIPs are utilized in various sample preparation techniques such as SPE, SPME, SBSE and MEPS. Nevertheless, molecularly imprinted polymers suffer from thermal (stable only up to 150 degrees C) and mechanical stability issues, improper porosity and poor capacity. The sol-gel methodology as a promising alternative to address these limitations allowing the production of sorbents with controlled porosity and higher surface area. Thus the combination of molecularly imprinted technology and sol-gel technology can create influential materials with high selectivity, high capacity and high thermal stability. This work aims to present an overview of molecularly imprinted sol-gel polymerization methods and their applications in analytical and bioanalytical fields.

  • 11.
    Rostami, Jowan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Mathew, A. P.
    Edlund, Ulrica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Zwitterionic acetylated cellulose nanofibrils2019Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, nr 17, artikel-id 3147Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A strategy is devised to synthesize zwitterionic acetylated cellulose nanofibrils (CNF). The strategy included acetylation, periodate oxidation, Schiff base reaction, borohydride reduction, and a quaternary ammonium reaction. Acetylation was performed in glacial acetic acid with a short reaction time of 90 min, yielding, on average, mono-acetylated CNF with hydroxyl groups available for further modification. The products from each step were characterized by FTIR spectroscopy, ζ-potential, SEM-EDS, AFM, and titration to track and verify the structural changes along the sequential modification route.

  • 12.
    Stenström, Patrik
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Andrén, Oliver C. J.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Malkoch, Michael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Fluoride-promoted esterification (FPE) chemistry: A robust route to Bis-MPA dendrons and their postfunctionalization2016Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 21, nr 3, artikel-id 366Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bifunctional dendrons based on 2,2-bis(methylol)propionic acid (bis-MPA) are highly desirable scaffolds for biomedical applications. This is due to their flawless nature and large and exact number of functional groups as well as being biodegradable and biocompatible. Herein, we describe a facile divergent growth approach to their synthesis from monobenzylated tetraethylene glycol and post functionalization utilizing fluoride-promoted esterification (FPE) chemistry protocols. The scaffolds, presenting selectively deprotectable hydroxyls in the periphery and at the focal point, were isolated on a multigram scale with excellent purity up to the fourth generation dendron with a molecular weight of 2346 Da in seven reactions with a total yield of 50%. The third generation dendron was used as a model compound to demonstrate its functionalizability. Selective deprotection of the dendron's focal point was achieved with an outstanding yield of 94%, and biotin as well as azido functionalities were introduced to its focal point and periphery, respectively, through FPE chemistry. Bulky disperse red dyes were clicked through CuAAC to the dendron's azido groups, giving a biotinylated dendron with multivalent dyes with a molecular weight of 6252 Da in a total yield of 37% in five reactions with an average yield of 82% starting from the third generation focally and peripherally protected dendron. FPE chemistry proved to be a superb improvement over previous protocols towards bis-MPA dendrons as high purity and yields were obtained with less toxic solvents and greatly improved monomer utilization.

  • 13.
    Stenström, Patrik
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Manzanares, D.
    Zhang, Yuning
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ceña, V.
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Evaluation of amino-functional polyester dendrimers based on Bis-MPA as nonviral vectors for siRNA delivery2018Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 23, nr 8, artikel-id 2028Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Herein, we present the first evaluation of cationic dendrimers based on 2,2-bis(methylol)propionic acid (bis-MPA) as nonviral vectors for transfection of short interfering RNA (siRNA) in cell cultures. The study encompassed dendrimers of generation one to four (G1-G4), modified to bear 6-48 amino end-groups, where the G2-G4 proved to be capable of siRNA complexation and protection against RNase-mediated degradation. The dendrimers were nontoxic to astrocytes, glioma (C6), and glioblastoma (U87), while G3 and G4 exhibited concentration dependent toxicity towards primary neurons. The G2 showed no toxicity to primary neurons at any of the tested concentrations. Fluorescence microscopy experiments suggested that the dendrimers are highly efficient at endo-lysosomal escape since fluorescently labeled dendrimers were localized specifically in mitochondria, and diffuse cytosolic distribution of fluorescent siRNA complexed by dendrimers was observed. This is a desired feature for intracellular drug delivery, since the endocytic pathway otherwise transfers the drugs into lysosomes where they can be degraded without reaching their intended target. siRNA-transfection was successful in C6 and U87 cell lines using the G3 and G4 dendrimers followed by a decrease of approximately 20% of target protein p42-MAPK expression.

  • 14. Zhang, M.
    et al.
    Song, Ce
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Tian, Y.
    Comprehensive theoretical studies on the reaction of 1-bromo-3,3,3- trifluoropropene with OH free radicals2013Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 18, nr 7, s. 7873-7885Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The potential energy surfaces (PES) for the reaction of 1-bromo-3,3,3- trifluoropropene (CF3CHCBrH) with hydroxyl (OH) free radicals is probed theoretically at the CCSD/aug-cc-pVDZ//B3LYP/6-311++G(d,p) level of theory. All the possible stationary and first-order saddle points along the reaction paths were verified by the vibrational analysis. The calculations account for all the product channels. Based on the calculated CCSD/aug-cc-pVDZ potential energy surface, the possible reaction mechanism is discussed. Six distinct reaction pathways of 1-bromo-3,3,3-trifluoropropene (BTP) with OH are investigated. The geometries, reaction enthalpies and energy barriers are determined. Canonical transition-state theory with Wigner tunneling correction was used to predict the rate constants for the temperature range of 290-3,000 K without any artificial adjustment, and the computed rate constants for elementary channels can be accurately fitted with three-parameter Arrhenius expressions. OH addition reaction channel and the H atom abstraction channels related to the carbon-carbon double bond are found to be the main reaction channels for the reaction of 1-bromo-3,3,3-trifluoropropene (CF3CHCBrH) with hydroxyl (OH) free radicals while the products leading to CF3CHCH + BrOH and COHF 2CHCBrH + F play a negligible role.

  • 15.
    Zohdi, Zeynab
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Karolinska Inst, Dept Clin Neurosci, Ctr Psychiat Res, SE-17176 Solna, Sweden ; Univ Bu Ali Sina, Dept Chem, Hamadan 65174, Iran.
    Hashemi, Mahdi
    Univ Bu Ali Sina, Dept Chem, Hamadan 65174, Iran..
    Uheida, Abdusalam
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Moein, Mohammad Mahdi
    Karolinska Inst, Dept Clin Neurosci, Ctr Psychiat Res, SE-17176 Solna, Sweden..
    Abdel-Rehim, Mohamed
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Karolinska Inst, Dept Clin Neurosci, Ctr Psychiat Res, SE-17176 Solna, Sweden Dept Appl Phys, SE-16440 Stockholm, Sweden..
    Graphene Oxide Tablets for Sample Preparation of Drugs in Biological Fluids: Determination of Omeprazole in Human Saliva for Liquid Chromatography Tandem Mass Spectrometry2019Ingår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, nr 7, artikel-id 1191Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, a novel sort of sample preparation sorbent was developed, by preparing thin layer graphene oxide tablets (GO-Tabs) utilizing a mixture of graphene oxide and polyethylene glycol on a polyethylene substrate. The GO-Tabs were used for extraction and concentration of omeprazole (OME) in human saliva samples. The determination of OME was carried out using liquid chromatography-tandem mass spectrometry (LC-MS/MS) under gradient LC conditions and in the positive ion mode (ESI+) with mass transitions of m/z 346.3 -> 198.0 for OME and m/z 369.98 -> 252.0 for the internal standard. Standard calibration for the saliva samples was in the range of 2.0-2000 nmol L-1. Limits of detection and quantification were 0.05 and 2.0 nmol L-1, respectively. Method validation showed good method accuracy and precision; the inter-day precision values ranged from 5.7 to 8.3 (%RSD), and the accuracy of determinations varied from -11.8% to 13.3% (% deviation from nominal values). The extraction recovery was 60%, and GO-Tabs could be re-used for more than ten extractions without deterioration in recovery. In this study, the determination of OME in real human saliva samples using GO-Tab extraction was validated.

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