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https://www.readbyqxmd.com/read/29166537/database-of-absorption-and-fluorescence-spectra-of-300-common-compounds-for-use-in-photochemcad
#1
Masahiko Taniguchi, Jonathan S Lindsey
The design of new molecules for photochemical studies typically requires knowledge of spectral features of pertinent chromophores beginning with the absorption spectrum (λabs ) and accompanying molar absorption coefficient (ε, M(-1) cm(-1) ) and often extending to the fluorescence spectrum (λem ) and fluorescence quantum yield (Φf ), where the fluorescence properties may be of direct relevance or useful as proxies to gain insight into the nature of the first excited singlet state. PhotochemCAD databases, developed over a period of 30 years, are described here...
November 22, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/29166121/photoinduced-transformations-of-indole-and-3-formylindole-monomers-isolated-in-low-temperature-matrices
#2
Igor Reva, Leszek Lapinski, A J Lopes Jesus, Maciej J Nowak
Photochemical transformations were studied for monomers of indole and 3-formylindole isolated in low-temperature noble-gas matrices. Upon UV (λ > 270 nm) irradiation of indole trapped in argon and neon matrices, the initial 1H-form of the compound converted into the 3H-tautomer. Alongside this photoinduced hydrogen-atom transfer, an indolyl radical was also generated by photodetachment of the hydrogen atom from the N1-H bond. Excitation of 3-formylindole isolated in an argon matrix with UV (λ > 335 nm) light led to interconversion between the two conformers of the 1H-tautomer, differing from each other in the orientation of the formyl group (cis or trans)...
November 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166109/temperature-and-chain-length-dependence-of-ultrafast-vibrational-dynamics-of-thiocyanate-in-alkylimidazolium-ionic-liquids-a-random-walk-on-a-rugged-energy-landscape
#3
Thomas Brinzer, Sean Garrett-Roe
Ultrafast two-dimensional infrared spectroscopy of a thiocyanate vibrational probe (SCN(-)) was used to investigate local dynamics in alkylimidazolium bis-[trifluoromethylsulfonyl]imide ionic liquids ([Imn,1][Tf2N], n = 2, 4, 6) at temperatures from 5 to 80 °C. The rate of frequency fluctuations reported by SCN(-) increases with increasing temperature and decreasing alkyl chain length. Temperature-dependent correlation times scale proportionally to temperature-dependent bulk viscosities of each ionic liquid studied...
November 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166097/volatility-of-the-catalytic-hydrogenation-products-of-1-4-bis-phenylethynyl-benzene
#4
Hom N Sharma, Elizabeth A Sangalang, Cheng K Saw, Gareth A Cairns, William McLean, Robert S Maxwell, Long N Dinh
Measurements of equilibrium vapor pressures by effusion thermogravimetry and melting points by differential scanning calorimetry reveal that the melting temperature and equilibrium vapor pressures of 1,4-bis(phenylethynyl)benzene (DEB) do not vary monotonically with the hydrogenation extent. Contrary to intuition which suggests increasing volatility with hydrogenation, results indicate decreasing volatility for the first two hydrogenation steps before a non-monotonic upward trend, in which trans-isomers are less volatile...
November 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166047/ortho-para-interconversion-in-cation-water-complexes-the-case-of-v-h2o-and-nb-h2o-clusters
#5
T B Ward, E Miliordos, P D Carnegie, S S Xantheas, M A Duncan
Vanadium and niobium cation-water complexes, V(+)(H2O) and Nb(+)(H2O), are produced by laser vaporization in a pulsed supersonic expansion, mass selected in a time-of-flight spectrometer, and studied with infrared photodissociation spectroscopy using rare gas atom (Ar, Ne) complex predissociation. The vibrational bands measured in the O-H stretching region contain K-type rotational sub-band structure, which provides insight into the structures of these complexes. However, rotational sub-bands do not exhibit the simple patterns seen previously for other metal ion-water complexes...
June 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29165994/from-graphene-oxide-to-reduced-graphene-oxide-impact-on-physiochemical-and-mechanical-properties-of-graphene%C3%A2-cement-composites
#6
Aliakbar Gholampour, Meisam Valizadeh Kiamahalleh, Diana N H Tran, Togay Ozbakkaloglu, Dusan Losic
Graphene materials have been extensively explored and successfully used to improve performances of cement composites. These formulations were mainly optimized based on different dosages of graphene additives, but with lack of understanding how other parameters such as surface chemistry, size, charge, and defects of graphene structures could impact on physiochemical and mechanical properties of final material. This paper presents the first experimental study to evaluate the influence of oxygen functional groups of graphene and defectiveness of graphene structures on the axial tension and compression properties of graphene-cement mortar composites...
November 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29165992/quantitative-chemical-analysis-at-the-nanoscale-using-the-ptir-technique
#7
Georg Ramer, Vladimir Aksyuk, Andrea Centrone
Photothermal induced resonance (PTIR), also known as AFM-IR, is a scanning probe technique that provides sample composition information with a lateral resolution down to 20 nm. Interest in PTIR stems from its ability to identify unknown samples at the nanoscale thanks, in first approximation, to the direct comparability of PTIR spectra with far-field infrared databases. The development of rapidly tuning quantum cascade lasers has increased the PTIR throughput considerably, making nanoscale hyper-spectral imaging within a reasonable timeframe possible...
November 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29165986/scalable-low-bandgap-sb2se3-thin-film-photocathodes-for-efficient-visible-near-infrared-solar-hydrogen-evolution
#8
Li Zhang, Yanbo Li, Changli Li, Qiao Chen, Zhen Zhen, Xin Jiang, Miao Zhong, Fuxiang Zhang, Hongwei Zhu
A highly efficient low-bandgap (1.2-0.8 eV) photoelectrode is critical for accomplishing efficient conversion of visible-near-infrared sunlight into storable hydrogen. Herein, we report Sb2Se3 polycrystalline thin film photocathode having a low-bandgap (1.2-1.1 eV) for efficient hydrogen evolution for wide solar-spectrum utilization. The photocathode was fabricated by a facile thermal evaporation of single Sb2Se3 powder source onto the Mo-coated soda-lime glass substrate, followed by annealing under Se vapor and surface modification with anti-photocorrosive CdS/TiO2 bilayer and Pt catalyst...
November 22, 2017: ACS Nano
https://www.readbyqxmd.com/read/29165906/noninvasive-high-speed-near-infrared-imaging-of-the-biomolecular-distribution-and-molecular-mechanism-of-embryonic-development-in-fertilized-fish-eggs
#9
Mika Ishigaki, Takashi Nishii, Paralee Puangchit, Yui Yasui, Christian W Huck, Yukihiro Ozaki
In the present study, the distribution of biomaterials and its molecular mechanism of embryonic development in Japanese medaka fish were analyzed nondestructively and noninvasively without staining using near-infrared (NIR) imaging. The microscope NIR imaging system used in this research was a device capable of ultra-high-speed imaging; using this system, one can acquire microscopic imaging data in a few seconds. Therefore, the medaka eggs remained alive throughout measurements and were successfully monitored in vivo...
November 22, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/29165882/single-pixel-black-phosphorus-photodetector-for-near-infrared-imaging
#10
Jinshui Miao, Bo Song, Zhihao Xu, Le Cai, Suoming Zhang, Lixin Dong, Chuan Wang
Infrared imaging systems have wide range of military or civil applications and 2D nanomaterials have recently emerged as potential sensing materials that may outperform conventional ones such as HgCdTe, InGaAs, and InSb. As an example, 2D black phosphorus (BP) thin film has a thickness-dependent direct bandgap with low shot noise and noncryogenic operation for visible to mid-infrared photodetection. In this paper, the use of a single-pixel photodetector made with few-layer BP thin film for near-infrared imaging applications is demonstrated...
November 22, 2017: Small
https://www.readbyqxmd.com/read/29165872/manganese-dioxide-coated-ws2-fe3-o4-ssio2-nanocomposites-for-ph-responsive-mr-imaging-and-oxygen-elevated-synergetic-therapy
#11
Guangbao Yang, Rui Zhang, Chao Liang, He Zhao, Xuan Yi, Sida Shen, Kai Yang, Liang Cheng, Zhuang Liu
Recently, the development of multifunctional theranostic nanoplatforms to realize tumor-specific imaging and enhanced cancer therapy via responding or modulating the tumor microenvironment (TME) has attracted tremendous interests in the field of nanomedicine. Herein, tungsten disulfide (WS2 ) nanoflakes with their surface adsorbed with iron oxide nanoparticles (IONPs) via self-assembly are coated with silica and then subsequently with manganese dioxide (MnO2 ), on to which polyethylene glycol (PEG) is attached...
November 22, 2017: Small
https://www.readbyqxmd.com/read/29165498/tomographic-magnetic-particle-imaging-of-cancer-targeted-nanoparticles
#12
Hamed Arami, Eric Teeman, Alyssa Troksa, Haydin Bradshaw, Katayoun Saatchi, Asahi Tomitaka, Sanjiv Sam Gambhir, Urs O Häfeli, Denny Liggitt, Kannan M Krishnan
Magnetic Particle Imaging (MPI) is an emerging, whole body biomedical imaging technique, with sub-millimeter spatial resolution and high sensitivity to a biocompatible contrast agent consisting of an iron oxide nanoparticle core and a biofunctionalized shell. Successful application of MPI for imaging of cancer depends on the nanoparticles (NPs) accumulating at tumors at sufficient levels relative to other sites. NPs' physiochemical properties such as size, crystallographic structure and uniformity, surface coating, stability, blood circulation time and magnetization determine the efficacy of their tumor accumulation and MPI signal generation...
November 22, 2017: Nanoscale
https://www.readbyqxmd.com/read/29165472/intracellular-delivery-of-more-than-one-protein-with-spatio-temporal-control
#13
Miguel M Lino, Susana Simões, Sónia Pinho, Lino Ferreira
Transient, non-integrative modulation of cell function by intracellular delivery of proteins has high potential in cellular reprogramming, gene editing and therapeutic medicine applications. Unfortunately, the capacity to deliver multiple proteins intracellularly with temporal and spatial control has not been demonstrated. Here, we report a near infrared (NIR) laser-activatable nanomaterial that allows for precise control over the release of two proteins from a single nanomaterial. The nanomaterial is formed by gold nanorods (AuNRs) modified with single stranded DNA (ssDNA) to which complementary DNA-conjugated proteins are hybridized...
November 22, 2017: Nanoscale
https://www.readbyqxmd.com/read/29165446/up-conversion-luminescence-coupled-to-plasmonic-gold-nanorods-for-light-harvesting-and-hydrogen-production
#14
H AlGhamdi, K Katsiev, A K Wahab, J Llorca, H Idriss
The conversion of infrared light to visible-light which allows a larger fraction of sun-light to be used is needed to improve light-harvesting. In this work a tri-functional material composed of an up-converter (NaYF4-Yb-Tm), plasmonic gold nanorods and CdS was made photocatalytically active using 980 nm wavelength light for the reduction of H(+) to H2.
November 22, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29165380/direct-modification-of-microcrystalline-cellulose-with-ethylenediamine-for-use-as-adsorbent-for-removal-amitriptyline-drug-from-environment
#15
Roosevelt D S Bezerra, Régis C Leal, Mateus S da Silva, Alan I S Morais, Thiago H C Marques, Josy A Osajima, Andréia B Meneguin, Hernane da S Barud, Edson C da Silva Filho
Cellulose derivatives have been widely used as adsorbents for the removal of micropollutants such as drugs, dyes, and metals, due to their abundance, low cost and non-contaminating nature. In this context, several studies have been performed searching for new adsorbents (cellulose derivatives) efficient at contaminant removal from aqueous solutions. Thus, a new adsorbent was synthesized by chemical modification of cellulose with ethylenediamine in the absence of solvent and applied to the adsorption of amitriptyline (AMI) in aqueous solution...
November 22, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29165376/preparation-of-vitexin-nanoparticles-by-combining-the-antisolvent-precipitation-and-high-pressure-homogenization-approaches-followed-by-lyophilization-for-dissolution-rate-enhancement
#16
Chengbo Gu, Ziwei Liu, Xiaohan Yuan, Wang Li, Yuangang Zu, Yujie Fu
Vitexin, a natural flavonoid found in many medicinal plants, is well known for its rich pharmacological activities. However, the poor water solubility of vitexin has limited its therapeutic application. The aim of this study was to prepare the nanoparticles of vitexin by combining the antisolvent precipitation (ASP) and high pressure homogenization (HPH) approaches followed by lyophilization for improving the dissolution rate of this poorly water-soluble drug. The effects of main factors influencing the mean particle size (MPS) of vitexin were investigated and optimized...
November 22, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29165336/comparison-of-benchtop-fourier-transform-ft-and-portable-grating-scanning-spectrometers-for-determination-of-total-soluble-solid-contents-in-single-grape-berry-vitis-vinifera-l-and-calibration-transfer
#17
Hui Xiao, Ke Sun, Ye Sun, Kangli Wei, Kang Tu, Leiqing Pan
Near-infrared (NIR) spectroscopy was applied for the determination of total soluble solid contents (SSC) of single Ruby Seedless grape berries using both benchtop Fourier transform (VECTOR 22/N) and portable grating scanning (SupNIR-1500) spectrometers in this study. The results showed that the best SSC prediction was obtained by VECTOR 22/N in the range of 12,000 to 4000 cm(-1) (833-2500 nm) for Ruby Seedless with determination coefficient of prediction (Rp²) of 0.918, root mean squares error of prediction (RMSEP) of 0...
November 22, 2017: Sensors
https://www.readbyqxmd.com/read/29164925/express-mid-infrared-standoff-spectroscopy-using-a-combination-of-supercontinuum-radiation-with-compact-fabry-p%C3%A3-rot-filter-spectrometer
#18
Jakob Kilgus, Kristina Duswald, Gregor Langer, Markus Brandstetter
No abstract text is available yet for this article.
January 1, 2017: Applied Spectroscopy
https://www.readbyqxmd.com/read/29164901/co-amorphous-formation-of-high-dose-zwitterionic-compounds-with-amino-acids-to-improve-solubility-and-enable-parenteral-delivery
#19
Saijie Zhu, Huisheng Gao, Sreehari Babu, Sudhakar Garad
Solubilization of parenteral drugs is a high unmet need in both pre-clinical and clinical drug development. Recently, co-amorphous drug formulation has emerged as a new strategy to solubilize orally dosed drugs. The aim of the present study is to explore the feasibility of using the co-amorphous strategy to enable the dosing of parenteral zwitterionic drugs at a high concentration. A new screening procedure was established with solubility as the indicator for co-amorphous co-former selection, and lyophilization was established as the method for co-amorphous formulation preparation...
November 22, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/29164900/theory-of-transient-excited-state-absorptions-in-pentacene-and-derivatives-the-triplet-triplet-biexciton-versus-free-triplets
#20
Souratosh Khan, Sumit Mazumdar
Recent experiments in several singlet-fission materials have found that the triplet-triplet biexciton is either the primary product of photoexcitation, or has much longer lifetime than believed until now. It thus becomes essential to determine the difference in the spectroscopic signatures of the bound triplet-triplet and free triplets to distinguish between them optically. We report calculations of excited state absorptions (ESAs) from the singlet and triplet excitons and from the triplet-triplet biexciton for pentacene crystal with the herringbone structure and for nanocrystals of bis(triisopropylsilylethynyl) (TIPS)-pentacene...
November 22, 2017: Journal of Physical Chemistry Letters
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