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https://www.readbyqxmd.com/read/29150729/effect-of-microemulsion-structure-on-fluorescence-and-nonlinear-optical-properties-of-rhodamine-6g
#1
M Pourtabrizi, N Shahtahmassebi, A Kompany, S Sharifi
This study is conducted to investigate the effect of nano-droplets concentration and size on linear and nonlinear optical properties of Rhodamine 6G by UV-Vis, spectrofluorometer and Z-Scan techniques. Nano-droplets were prepared by mixture of AOT, n-Decane and Water at three different water to surfactant molar ratios (W = 3, 6.7 and 40) and two dye to water mass ratios (R). At high enough dye concentration, the fluorescence intensity and its red shift depend on the concentration of dye in water nano-droplets (R)...
November 18, 2017: Journal of Fluorescence
https://www.readbyqxmd.com/read/29148717/raman-spectroscopy-of-single-light-absorbing-carbonaceous-particles-levitated-in-air-using-an-annular-laser-beam
#2
Masaru Uraoka, Keisuke Maegawa, Shoji Ishizaka
A laser trapping technique is a powerful means to investigate the physical and chemical properties of single aerosol particles in a non-contact manner. However, optical trapping of strongly light-absorbing particles such as black carbon or soot is quite difficult because the repulsive force caused by heat is orders of magnitude larger than the attractive force of radiation pressure. In this study, a laser trapping and Raman microspectroscopy system using an annular laser beam was constructed to achieve non-contact levitation of single light-absorbing particles in air...
November 17, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29144756/controlling-graphene-bio-interface-dispersions-in-animal-sera-for-enhanced-stability-and-reduced-toxicity
#3
Ajith Pattammattel, Paritosh Pande, Deepa Kuttappan, Megan Puglia, Ashis K Basu, Mary Amalaradjou, Challa V Kumar
Controlling the graphene-bio interface is important for biological applications of graphene, which is touted as the wonder material of the new century. Graphene samples made in animal sera indicated low toxicity to cells and nematodes, due to the adsorption of the serum proteins on the nascent graphene sheets. The graphite samples were exfoliated in 6 different animal sera, using three different methods, shear reactor, the kitchen blender and by ultrasonication, and maximum efficiency was noted with the kitchen blender...
November 16, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29143054/amidoboranes-of-rubidium-and-caesium-the-last-missing-members-of-the-alkali-metal-amidoborane-family
#4
Rafał Owarzany, Tomasz Jaroń, Piotr J Leszczyński, Karol J Fijalkowski, Wojciech Grochala
We report the synthesis and physicochemical characterization of two ammonia borane derivatives: rubidium amidoborane (RbNH2BH3) and caesium amidoborane (CsNH2BH3). Both compounds undergo solid-solid phase transition upon heating and then evolve pure hydrogen at temperatures lower than 125 °C. The phase transition is clearly seen in the Raman spectra. We present crystal structures of both low- and high-temperature forms of the title compounds which were solved from powder X-ray data.
November 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29140342/fiber-format-dual-comb-coherent-raman-spectrometer
#5
Nicola Coluccelli, Christopher R Howle, Kenneth McEwan, Yuchen Wang, Toney Teddy Fernandez, Alessio Gambetta, Paolo Laporta, Gianluca Galzerano
We demonstrate a fiber-format system for dual-comb coherent anti-Stokes Raman scattering spectroscopy. The system is based on two ytterbium fiber (Yb) femtosecond lasers at repetition frequencies of 94 MHz, a Yb amplifier, and a photonic crystal fiber for spectral broadening and generation of pulses with a central wavelength of 1040 nm and durations in the sub-20-fs regime. We observed Raman spectra of acetonitrile and ethyl acetate with spectral coverage from 100 to 1300  cm(-1), resolution of 8  cm(-1), and a signal-to-noise ratio of around 100, when averaging over 10 acquisitions...
November 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/29140287/interaction-between-diethyldithiocarbamate-and-cu-ii-on-gold-in-non-cyanide-wastewater
#6
Nguyễn Hoàng Ly, Thanh Danh Nguyen, Kyung-Duk Zoh, Sang-Woo Joo
A surface-enhanced Raman scattering (SERS) detection method for environmental copper ions (Cu(2+)) was developed according to the vibrational spectral change of diethyldithiocarbamate (DDTC) on gold nanoparticles (AuNPs). The ultraviolet-visible (UV-Vis) absorption spectra indicated that DDTC formed a complex with Cu(2+), showing a prominent peak at ~450 nm. We found Raman spectral changes in DDTC from ~1490 cm(-1) to ~1504 cm(-1) on AuNPs at a high concentration of Cu(2+) above 1 μM. The other ions of Zn(2+), Pb(2+), Ni(2+), NH₄⁺, Mn(2+), Mg(2+), K⁺, Hg(2+), Fe(2+), Fe(3+), Cr(3+), Co(2+), Cd(2+), and Ca(2+) did not produce such spectral changes, even after they reacted with DDTC...
November 15, 2017: Sensors
https://www.readbyqxmd.com/read/29140085/electronic-structure-of-anilinopyridinate-supported-ru2-5-paddlewheel-compounds
#7
Amanda R Corcos, Michael D Roy, Michelle M Killian, Stephanie Dillon, Thomas C Brunold, John F Berry
The electronic structures of the diruthenium compounds Ru2(ap)4Cl (1, ap = 2-anilinopyridinate) and Ru2(ap)4OTf (2) were investigated with UV-vis, resonance Raman, and magnetic circular dichroism (MCD) spectroscopies; SQUID magnetometry; and density functional theory (DFT) calculations. Both compounds have quartet spin ground states with large axial zero-field splitting of ∼60 cm(-1) that is characteristic of Ru2(5+) compounds having a (π*, δ*)(3) electron configuration and a Ru-Ru bond order of ∼2.5...
November 15, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29139244/raman-exfoliative-cytology-for-oral-precancer-diagnosis
#8
Aditi Sahu, Poonam Gera, Venkatesh Pai, Abhishek Dubey, Gunjan Tyagi, Mandavi Waghmare, Sandeep Pagare, Manoj Mahimkar, C Murali Krishna
Oral premalignant lesions (OPLs) such as leukoplakia, erythroplakia, and oral submucous fibrosis, often precede oral cancer. Screening and management of these premalignant conditions can improve prognosis. Raman spectroscopy has previously demonstrated potential in the diagnosis of oral premalignant conditions (in vivo), detected viral infection, and identified cancer in both oral and cervical exfoliated cells (ex vivo). The potential of Raman exfoliative cytology (REC) in identifying premalignant conditions was investigated...
November 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/29137201/review-on-sers-of-bacteria
#9
REVIEW
Pamela A Mosier-Boss
Surface enhanced Raman spectroscopy (SERS) has been widely used for chemical detection. Moreover, the inherent richness of the spectral data has made SERS attractive for use in detecting biological materials, including bacteria. This review discusses methods that have been used to obtain SERS spectra of bacteria. The kinds of SERS substrates employed to obtain SERS spectra are discussed as well as how bacteria interact with silver and gold nanoparticles. The roll of capping agents on Ag/Au NPs in obtaining SERS spectra is examined as well as the interpretation of the spectral data...
November 13, 2017: Biosensors
https://www.readbyqxmd.com/read/29137126/carbon-nanotubes-effect-on-mitochondrial-oxygen-flux-dynamics-polarography-experimental-study-and-machine-learning-models-using-star-graph-trace-invariants-of-raman-spectra
#10
Michael González-Durruthy, Jose M Monserrat, Bakhtiyor Rasulev, Gerardo M Casañola-Martín, José María Barreiro Sorrivas, Sergio Paraíso-Medina, Víctor Maojo, Humberto González-Díaz, Alejandro Pazos, Cristian R Munteanu
This study presents the impact of carbon nanotubes (CNTs) on mitochondrial oxygen mass flux (Jm) under three experimental conditions. New experimental results and a new methodology are reported for the first time and they are based on CNT Raman spectra star graph transform (spectral moments) and perturbation theory. The experimental measures of Jm showed that no tested CNT family can inhibit the oxygen consumption profiles of mitochondria. The best model for the prediction of Jm for other CNTs was provided by random forest using eight features, obtaining test R-squared (R²) of 0...
November 11, 2017: Nanomaterials
https://www.readbyqxmd.com/read/29136881/monitoring-of-tablet-coating-processes-with-colored-coatings
#11
Shirin Barimani, Peter Kleinebudde
Endpoints of coating processes for colored tablets were determined using in-line Raman spectroscopy. Coatings were performed with six commercially available formulations of pink, yellow, red, beige, green and blue color. The coatings were comprising pigments and/or dyes, some causing fluorescence and interfering the Raman signal. Using non-contact optics, a Raman probe was used as process analytical technology (PAT) tool, and acquired spectra were correlated to the sprayed mass of aqueous coating suspension...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136829/au-pt-bimetallic-nanoparticles-decorated-on-sulfonated-nitrogen-sulfur-co-doped-graphene-for-simultaneous-determination-of-dopamine-and-uric-acid
#12
Kangning Zhang, Xiaoling Chen, Zhuang Li, Yan Wang, Sen Sun, Li'na Wang, Tong Guo, Dongxia Zhang, Zhonghua Xue, Xibin Zhou, Xiaoquan Lu
In this work, a novel nanohybrid (AuPtNPs/S-NS-GR) of well-defined Au-Pt bimetallic nanoparticles (Au-PtNPs) decorated on sulfonated nitrogen sulfur co-doped graphene (S-NS-GR) was developed. Firstly, nitrogen sulfur co-doped graphene (NS-GR) was synthesized by one-step thermal annealing method. Secondly, phenyl SO3H- group was introduced onto the surface of NS-GR via diazotization reaction, which could provide more binding sites for the formation of metal nanoparticles. Finally, Au-Pt bimetallic nanoparticles were anchored on the surface of S-NS-GR by using electrochemical deposition...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136825/determining-moisture-content-in-pasta-by-vibrational-spectroscopy
#13
Tomasz Czaja, Ewelina Kuzawińska, Aldona Sobota, Roman Szostak
Pasta aside from bread is the most consumed cereal-based product in the world. Its taste and cooking ease makes it the basis of many cuisines. The pasta dough formed by mixing flour and water is extruded through an extrusion die to mould the appropriate pasta form and is dried to obtain a stable product. The concentration of moisture in the pasta dough is a one of key parameters determining the final quality of the product. Monitoring the moisture content of pasta after extrusion is also critically important...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136591/direct-comparison-of-low-and-mid-frequency-raman-spectroscopy-for-quantitative-solid-state-pharmaceutical-analysis
#14
Tiina Lipiäinen, Sara J Fraser-Miller, Keith C Gordon, Clare J Strachan
This study considers the potential of low-frequency (terahertz) Raman spectroscopy in the quantitative analysis of ternary mixtures of solid-state forms. Direct comparison between low-frequency and mid-frequency spectral regions for quantitative analysis of crystal form mixtures, without confounding sampling and instrumental variations, is reported for the first time. Piroxicam was used as a model drug, and the low-frequency spectra of piroxicam forms β, α2 and monohydrate are presented for the first time...
November 11, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/29136472/thickness-dependent-phonon-renormalization-and-enhanced-raman-scattering-in-ultrathin-silicon-nanomembranes
#15
Seonwoo Lee, Kangwon Kim, Krishna P Dhakal, Hyunmin Kim, Won Seok Yun, Jae Dong Lee, Hyeonsik Cheong, Jong-Hyun Ahn
We report on the thickness-dependent Raman spectroscopy of ultrathin silicon (Si) nanomembranes (NMs) whose thicknesses range from 2 to 18 nm using several excitation energies. We observe that the Raman intensity depends on the thickness and the excitation energy due to the combined effects of interference and resonance from the band-structure modulation. Furthermore, confined acoustic phonon modes in the ultrathin Si NMs were observed in ultralow-frequency Raman spectra, and strong thickness dependence was observed near the quantum limit, which was explained by calculations based on a photoelastic model...
November 14, 2017: Nano Letters
https://www.readbyqxmd.com/read/29135254/local-structure-of-li-in-concentrated-ethylene-carbonate-solutions-studied-by-low-frequency-raman-scattering-and-neutron-diffraction-with-6-li-7-li-isotopic-substitution-methods
#16
Shunya Maeda, Yasuo Kameda, Yuko Amo, Takeshi Usuki, Kazutaka Ikeda, Toshiya Otomo, Maho Yanagisawa, Shiro Seki, Nana Arai, Hikari Watanabe, Yasuhiro Umebayashi
Isotropic Raman scattering and time-of-flight neutron diffraction measurements were carried out for concentrated LiTFSA-EC solutions in order to obtain structural insight on solvated Li+ as well as the structure of contact ion pair, Li+…TFSA-, formed in highly concentrated EC solutions. Symmetrical stretching vibrational mode of solvated Li+ and solvated Li+…TFSA- ion pair were observed at ν = 168~177 and 202~224 cm-1, respectively. Detailed structural properties of solvated Li+ and Li+…TFSA- contact ion pair were derived from the least squares fitting analysis of first-order difference function, ΔLi(Q), between neutron scattering cross sections observed for 6Li/7Li isotopically substituted 10 and 25 mol% *LiTFSA-ECd4 solutions...
November 14, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29135238/elucidating-protein-ligand-recognition-with-combined-surface-plasmon-resonance-and-surface-enhanced-raman-spectroscopy
#17
Ju-Young Kim, Zhi-Cong Zeng, Lifu Xiao, Zachary D Schultz
The ability to distinguish between specific and non-specific binding is important for assessing the interactions between protein receptors and ligands. Surface plasmon resonance (SPR) spectroscopy is an advanced tool to measure the binding events, yet the ability to distinguish between specific and non-specific binding remains a limitation. To address this problem, we use SPR spectroscopy correlated with surface enhanced Raman scattering (SERS). The chemical information present in SERS spectra provides insight into the molecular interactions between functionalized nanoparticles and proteins, which are not detectable by SPR alone...
November 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29135232/confocal-raman-microscopy-for-the-determination-of-protein-and-quaternary-ammonium-ion-loadings-in-biocatalytic-membranes-for-electrochemical-energy-conversion-and-storage
#18
Rong Cai, Sofiene Abdellaoui, Jay P Kitt, Cullen Irvine, Joel Harris, Shelley D Minteer, Carol Korzeniewski
The need to immobilize active enzyme, while ensuring high rates of substrate turnover and electronic charge transfer with an electrode, is a centrally important challenge in the field of bioelectrocatalysis. In this work, we demonstrate the use of confocal Raman microscopy as a tool for quantitation and molecular-scale structural characterization of ionomers and proteins within biocatalytic membranes to aid in the development of energy efficient biofuel cells. A set of recently available short side chain Aquivion ionomers spanning a range of equivalent weight (EW) suitable for enzyme immobilization was investigated...
November 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29135230/multidimensional-spectral-fingerprints-of-a-new-family-of-coherent-analytical-spectroscopies
#19
Nathan Andrew Neff-Mallon, John C Wright
Triply Resonant Sum Frequency (TRSF) and Doubly Vibrationally Enhanced (DOVE) spectroscopies are examples of a recently developed family of Coherent Multidimensional Spectroscopies (CMDS) that are analogous to current analytical spectroscopies. They are based on creating quantum mechanical superposition states that are fully coherent and lack intermediate quantum state populations that cause quenching or other relaxation effects. They provide multidimensional spectral fingerprints consisting of mixtures of vibrational and electronic states...
November 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29135226/raman-dip-deuterium-isotope-probing-reveals-microbial-metabolism-at-the-single-cell-level
#20
Jiabao Xu, Di Zhu, Aliyu Ibrahim, Christopher C R Allen, Christopher M Gibson, Patrick William Fowler, Yizhi Song, Wei E Huang
We illustrate that single-cell Raman microspectroscopy, coupled with deuterium isotope probing (Raman-DIP), provides a culture-independent and non-destructive approach to probe metabolic pathways of carbon substrates at the single-cell level. We find a clearly distinguishable C-D vibration band at 2070 - 2300 cm-1 in single-cell Raman spectra (SCRS) when Escherichia coli used deuterated glucose and Pseudomonas sp. used deuterated naphthalene as sole carbon sources. The intensity of the C-D band is proportional to the extent of deuteration in carbon source, and as low as 5% deuteration can be distinguished by analysis of SCRS...
November 14, 2017: Analytical Chemistry
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