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https://read.qxmd.com/read/30763517/in-situ-nanoscale-redox-mapping-using-tip-enhanced-raman-spectroscopy
#1
Gyeongwon Kang, Muwen Yang, Michael Mattei, George C Schatz, Richard P Van Duyne
Electrochemical atomic force microscopy tip-enhanced Raman spectroscopy (EC-AFM-TERS) was used for the first time to spatially resolve local heterogeneity in redox behavior on an electrode surface in-situ and at the nanoscale. A structurally well-defined Au(111) nanoplate located on a polycrystalline ITO substrate was studied to examine nanoscale redox contrast across the two electrode materials. By monitoring the TERS intensity of adsorbed Nile Blue (NB) molecules on the electrode surface, TERS maps were acquired with different applied potentials...
February 14, 2019: Nano Letters
https://read.qxmd.com/read/30762369/c3n5-a-low-bandgap-semiconductor-containing-an-azo-linked-carbon-nitride-framework-for-photocatalytic-photovoltaic-and-adsorbent-applications
#2
Pawan Kumar, Ehsan Vahidzadeh, Ujwal Kumar Thakur, Piyush Kar, Kazi Mohammad Alam, Ankur Goswami, Najia Mahdi, Kai Cui, Guy M Bernard, Vladimir K Michaelis, Karthik Shankar
Modification of carbon nitride based polymeric 2D materials for tailoring their optical, electronic and chemical properties for various applications has gained significant interest. The present report demonstrates the synthesis of a novel modified carbon nitride framework with a remarkable 3:5 C:N stoichiometry (C3N5) and an electronic bandgap of 1.76 eV, by thermal deammoniation of melem hydrazine precursor. Characterization revealed that in C3N5 polymer, two s-heptazine units are bridged together with azo linkage, which constitutes an entirely new and different bonding fashion from g-C3N4 where three heptazine units are linked together with tertiary nitrogen...
February 14, 2019: Journal of the American Chemical Society
https://read.qxmd.com/read/30759840/the-recent-advances-in-raman-microscopy-and-imaging-techniques-for-biosensors
#3
Alexander Rzhevskii
Raman microspectroscopy is now well established as one of the most powerful analytical techniques for a diverse range of applications in physical (material) and biological sciences. Consequently, the technique provides exceptional analytical opportunities to the science and technology of biosensing due to its capability to analyze both parts of a biosensor system-biologically sensitive components, and a variety of materials and systems used in physicochemical transducers. Recent technological developments in Raman spectral imaging have brought additional possibilities in two- and three-dimensional (2D and 3D) characterization of the biosensor's constituents and their changes on a submicrometer scale in a label-free, real-time nondestructive method of detection...
February 12, 2019: Biosensors
https://read.qxmd.com/read/30759690/three-tesla-multiparametric-magnetic-resonance-imaging-comparison-of-performance-with-and-without-endorectal-coil-for-prostate-cancer-detection-pi-rads%C3%A2-version-2-category-and-staging-with-whole-mount-histopathology-correlation
#4
Sohrab Afshari Mirak, Sepideh Shakeri, Amirhossein Mohammadian Bajgiran, Ely R Felker, Kyung Hyun Sung, Nazanin Hajarol Asvadi, Pooria Khoshnoodi, Daniela Markovic, Danielle Ponzini, Preeti Ahuja, Anthony Sisk, Robert E Reiter, David Lu, Steven S Raman
PURPOSE: We investigated the performance of 3 Tesla multiparametric magnetic resonance imaging with and without an endorectal coil to detect prostate cancer with a whole mount histopathology reference. MATERIALS AND METHODS: This retrospective HIPAA (Health Insurance Portability and Accountability Act) compliant, institutional review board approved, case-control study included patients who underwent 3 Tesla multiparametric magnetic resonance imaging with and without an endorectal coil from July 2009 to December 2016 prior to prostatectomy...
March 2019: Journal of Urology
https://read.qxmd.com/read/30758186/multi-color-raman-beads-for-multiplexed-tumor-cell-and-tissue-imaging-and-in-vivo-tumor-spectral-detection
#5
Qingqing Jin, Xinli Fan, Changmai Chen, Lei Huang, Jing Wang, XinJing Tang
Developing new nanomaterials with strong and distinctive Raman vibrations in the biological Raman-silent region (1800-2800 cm -1) were highly desirable for Raman hyper-spectral detection and imaging in living cells and animals. Herein, polymeric nanoparticles with monomers containing alkyne, cyanide, azide and carbon-deuterate were prepared as Raman-active nanomaterials (Raman Beads) for bioimag-ing applications. Intense Raman signals were obtained due to the high density of alkyne, cyanide, azide and carbon-deuterate in single nanoparticles, in absence of metal (such as Au or Ag) as Raman enhancers...
February 13, 2019: Analytical Chemistry
https://read.qxmd.com/read/30755663/chromophore-binding-to-two-cysteines-increases-quantum-yield-of-near-infrared-fluorescent-proteins
#6
David Buhrke, Neslihan N Tavraz, Daria M Shcherbakova, Luisa Sauthof, Marcus Moldenhauer, Francisco Vélazquez Escobar, Vladislav V Verkhusha, Peter Hildebrandt, Thomas Friedrich
Phytochromes are red/far-red light sensing photoreceptors employing linear tetrapyrroles as chromophores, which are covalently bound to a cysteine (Cys) residue in the chromophore-binding domain (CBD, composed of a PAS and a GAF domain). Recently, near-infrared (NIR) fluorescent proteins (FPs) engineered from bacterial phytochromes binding biliverdin IXα (BV), such as the iRFP series, have become invaluable probes for multicolor fluorescence microscopy and in vivo imaging. However, all current NIR FPs suffer from relatively low brightness...
February 12, 2019: Scientific Reports
https://read.qxmd.com/read/30744770/low-surface-energy-and-ph-effect-on-sno%C3%A2-nanoparticles-formation-for-supercapacitor-applications
#7
B Saravanakumar, G Ravi, V Ganesh, S Ravichandran, A Sakunthala, R Yuvakkumar
The SnO₂ nanoparticles formation by hydrothermal method at different experimental conditions such as temperature, pH, reaction time, and capping agent (cetyltrimethylammonium bromide), was studied. X-ray diffraction results confirmed regular rutile crystal structure of SnO₂. The characteristic Raman peak observed at 635 cm-1 corresponded to A1g modes of Sn-O vibrations. The study of optical property using photoluminescence confirmed the emissive spectra of SnO₂. The infrared peak observed at 618 cm-1 corresponded to E u modes of Sn-O vibrations of TO phonon because of E ⊥ to c -axis...
June 1, 2019: Journal of Nanoscience and Nanotechnology
https://read.qxmd.com/read/30742986/a-study-on-the-applicability-of-multiple-process-analysers-in-the-production-of-coated-pellets
#8
Klemen Korasa, Franc Vrečer
Process analytical technology (PAT) has become an important factor in design, analysis and control of complex technological processes. In the present study, pellet coating process was monitored using four different PAT approaches, i.e. near-infrared (NIR) spectroscopy, Raman spectroscopy, in-line image analysis, and spatial filtering technique (SFT).Robustness and accuracy of a novel in-line image analyser was studied during the active ingredient coating process on the pilot scale in the first part of the study...
February 8, 2019: International Journal of Pharmaceutics
https://read.qxmd.com/read/30741306/uv-raman-chemical-imaging-using-compressed-sensing
#9
Markus Nordberg, Lars Landström
Different chemical (hyperspectral) imaging techniques have proven to be powerful tools to provide and illustrate insightful data within a broad range of research areas. The present communication includes proof-of-principle results of UV Raman hyperspectral imaging, achieved via compressed sensing measurements using coded apertures (CA) and a reconstruction algorithm. The simple and cheap CA set up, obtained by a 50% overall transmissive random binary mask (chromium on fused silica with 100 μm × 100 μm pixel size) positioned at the entrance plane of an imaging spectrograph, resulted in an overall high throughput for the UV region of interest...
February 11, 2019: Analyst
https://read.qxmd.com/read/30739618/neural-predictors-and-effects-of-cognitive-behavioral-therapy-for-depression-the-role-of-emotional-reactivity-and-regulation
#10
Harry Rubin-Falcone, Jochen Weber, Ronit Kishon, Kevin Ochsner, Lauren Delaparte, Bruce Doré, Sudha Raman, Bryan T Denny, Maria A Oquendo, J John Mann, Jeffrey M Miller
BACKGROUND: Cognitive behavioral therapy (CBT) is an effective treatment for many patients suffering from major depressive disorder (MDD), but predictors of treatment outcome are lacking, and little is known about its neural mechanisms. We recently identified longitudinal changes in neural correlates of conscious emotion regulation that scaled with clinical responses to CBT for MDD, using a negative autobiographical memory-based task. METHODS: We now examine the neural correlates of emotional reactivity and emotion regulation during viewing of emotionally salient images as predictors of treatment outcome with CBT for MDD, and the relationship between longitudinal change in functional magnetic resonance imaging (fMRI) responses and clinical outcomes...
February 11, 2019: Psychological Medicine
https://read.qxmd.com/read/30735037/native-nano-electrospray-differential-mobility-analyzer-nes-gemma-enables-size-selection-of-liposomal-nanocarriers-combined-with-subsequent-direct-spectroscopic-analysis
#11
Victor U Weiss, Karin Wieland, Andreas Schwaighofer, Bernhard Lendl, Günter Allmaier
Gas-phase electrophoresis employing a nano Electrospray Differential Mobility Analyzer (nES DMA) aka Gas-phase Electrophoretic Mobility Molecular Analyzer (nES GEMMA) enables nanoparticle separation in the gas-phase according to their surface-dry diameter with number-based detection. Moreover, particles in the nanometer size range can be collected after size-selection on supporting materials. It has been shown by subsequent analyses employing orthogonal methods, for instance microscopic or antibody-based techniques, that the surface integrity of collected analytes remains intact...
February 8, 2019: Analytical Chemistry
https://read.qxmd.com/read/30734871/molecular-modeling-and-experimental-study-of-a-new-peptide-based-microextraction-fiber-for-preconcentrating-morphine-in-urine-samples
#12
Bamdad Riahi-Zanjani, Mahdi Balali-Mood, Zarrin Es'haghi, Ahmad Asoodeh, Adel Ghorani-Azam
Antimicrobial peptides (AMPs) are best known for their bactericidal properties; however, due to their unique and flexible structures, they have also been proposed as potential selective sorbents for specific molecules. In the present study, we aimed to design and produce a new peptide-based microextraction fiber for preconcentrating morphine in urine samples. The binding of morphine to the peptide was first evaluated by computational simulation using the Molecular Operating Environment (MOE) 2015.10 software...
February 8, 2019: Journal of Molecular Modeling
https://read.qxmd.com/read/30732809/effects-of-regenerated-cellulose-fiber-on-the-characteristics-of-myofibrillar-protein-gels
#13
Yinyu Zhao, Guanghong Zhou, Wangang Zhang
The study investigated the role of regenerated cellulose (RC) fiber (0, 5 g, 10 g, 15 g and 20 g/100 g) on water holding capacity (WHC), texture, dynamic rheological, secondary structures and microstructure of myofibrillar protein (MP) gels. It was found that the gel WHC and texture properties were enhanced with increased RC fiber. The rheological results indicated that RC fiber did not destroy the normal cross-link of MP, but enhanced the viscoelasticity. The microstructure images proved that RC fiber was filled in the gel network leading to uniform and compact gel structure...
April 1, 2019: Carbohydrate Polymers
https://read.qxmd.com/read/30732392/hyperspectral-spatially-offset-raman-spectroscopy-in-a-microfluidic-channel
#14
Moritz Matthiae, Anders Kristensen
Spatially offset Raman spectroscopy (SORS) enables one to distinguish chemical fingerprints of top and subsurface layers. In this paper, we apply SORS to a microfluidic two-layer system consisting of transparent liquid in a microchannel as the surface layer and microfluidic PDMS chip material as the sublayer. By using an imaging spectrograph connected to a microscope, we perform hyperspectral SORS acquisitions. Furthermore, the focus position z is translated. Thus, we combine the two methods of hyperspectral SORS and defocusing micro-SORS, which leads to an integral characterization of the layered system...
February 4, 2019: Optics Express
https://read.qxmd.com/read/30724262/the-effects-of-insoluble-dietary-fiber-on-myofibrillar-protein-gelation-microstructure-and-molecular-conformations
#15
Xinbo Zhuang, Minyi Han, Xiping Jiang, Yun Bai, Hengyue Zhou, Chunbao Li, Xing-Lian Xu, Guang-Hong Zhou
The effects of insoluble dietary fiber (IDF) on heat-induced gelation properties, such as microstructural changes and the molecular conformation of myofibrillar proteins (MP), were analyzed by image analyses and Raman spectroscopy. Scanning electron microscopy revealed that pure MP gelation contained a loose and dispersed network with interconnected water channels. With IDF addition, the lacunarity and the particle size of water pores both significantly decreased (P < 0.05) and fractal dimension significantly increased (P < 0...
March 1, 2019: Food Chemistry
https://read.qxmd.com/read/30721413/raman-spectroscopic-imaging-of-ph-values-in-cancerous-tissue-by-using-polyaniline-gold-nanoparticles
#16
Zicheng Li, Ling Xia, Gongke Li, Yuling Hu
A core-shell nanocomposite consisting of polyaniline and gold nanoparticles (PANI@AuNPs) is shown to enable intracellular monitoring of pH values by surface-enhanced Raman scattering (SERS) spectroscopy. The method exploits the pH-responsive property of PANI and the SERS-enhancing effect of AuNPs. The intensity of the PANI Raman peak at 1164 cm-1 decreases on increasing the pH value from 4.6 to 7.4. This is the pH range encountered in normal cells and in cancer cells. The PANI@AuNPs were incorporated into HeLa cancer cells and 5 other kinds of cells for Raman based imaging of pH values...
February 5, 2019: Mikrochimica Acta
https://read.qxmd.com/read/30717306/deep-subwavelength-scale-light-focusing-and-confinement-in-nanohole-structured-mesoscale-dielectric-spheres
#17
Yinghui Cao, Zhenyu Liu, Oleg V Minin, Igor V Minin
One of the most captivating properties of dielectric mesoscale particles is their ability to form a sub-diffraction limited-field localization region, near their shadow surfaces. However, the transverse size of the field localization region of a dielectric mesoscale particle is usually larger than λ/3. In this present paper, for the first time, we present numerical simulations to demonstrate that the size of the electromagnetic field that forms in the localized region of the dielectric mesoscale sphere can be significantly reduced by introducing a nanohole structure at its shadow surface, which improves the spatial resolution up to λ/40 and beyond the solid immersion diffraction limit of λ/2 n ...
February 1, 2019: Nanomaterials
https://read.qxmd.com/read/30715527/molecular-mechanism-of-high-pressure-processing-for-improving-the-quality-of-low-salt-eucheuma-spinosum-chicken-breast-batters
#18
Dan He, Xixi Wang, Mingyan Ai, Yuting Kong, Lingyun Fu, Baodong Zheng, Hongbo Song, Qun Huang
To confirm the role of high-pressure processing in enhancing the quality of Eucheuma spinosum chicken breast batters, low-field nuclear magnetic resonance, scanning electron microscopy and Raman spectroscopy were used to explore the effect of E. spinosum and high-pressure processing on water migration, protein conformation, and microstructure in chicken breast batters. The water-holding capacity, surface hydrophobicity, and reactive sulfhydryl group content significantly increased as the pressure increased (0...
February 1, 2019: Poultry Science
https://read.qxmd.com/read/30715071/an-aligned-octahedral-core-in-a-nanocage-synthesis-plasmonic-and-catalytic-properties
#19
Evgeniia Khairullina, Kseniia Mosina, Rachelle M Choueiri, Andre Philippe Paradis, Ariel Alcides Petruk, German Sciaini, Elena Krivoshapkina, Anna Lee, Aftab Ahmed, Anna Klinkova
Plasmonic metal nanostructures with complex morphologies provide an important route to tunable optical responses and local electric field enhancement at the nanoscale for a variety of applications including sensing, imaging, and catalysis. Here we report a high-concentration synthesis of gold core-cage nanoparticles with a tethered and structurally aligned octahedral core and examine their plasmonic and catalytic properties. The obtained nanostructures exhibit a double band extinction in the visible-near infrared range and a large area electric field enhancement due to the unique structural features, as demonstrated using finite difference time domain (FDTD) simulations and confirmed experimentally using surface enhanced Raman scattering (SERS) tests...
February 4, 2019: Nanoscale
https://read.qxmd.com/read/30714717/nanomedicine-for-spontaneous-brain-tumors-a-companion-clinical-trial
#20
Hamed Arami, Chirag B Patel, Steven J Madsen, Peter J Dickinson, Ryan M Davis, Yitian Zeng, Beverly K Sturges, Kevin D Woolard, Frezghi G Habte, Demir Akin, Robert Sinclair, Sanjiv S Gambhir
Nanoparticles' enhanced permeation and retention (EPR) variations due to tumor heterogeneity in naturally occurring brain tumors are commonly neglected in preclinical nanomedicine studies. Recent pathological studies have shown striking similarities between brain tumors in humans and dogs, indicating that canine brain tumors may be a valuable model to evaluate nanoparticles' EPR in this context. We recruited canine clinical cases with spontaneous brain tumors to investigate nanoparticles' EPR in different brain tumor pathologies using surface-enhanced Raman spectroscopy (SERS)...
February 4, 2019: ACS Nano
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