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Infrared light

Kristiina Korhonen, Elina Smolander, Ossi Korhonen, Jarkko Ketolainen, Riikka Laitinen
We evaluated the physical stability of thin polymethacrylate-drug films under three different storage conditions by X-ray powder diffraction, differential scanning calorimetry, scanning electron microscopy, polarized light microscopy, and Fourier transform infrared spectroscopy. Mechanical properties i.e. elongation, mechanical strength, and in vitro drug release from the thin films were also determined during storage. The films consisted of ammonium methacrylate copolymer (RLPO)/dimethylaminoethyl methacrylate copolymer (EPO), polyvinylpyrroline (PVP)/polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus) and perphenazine (PPZ)...
March 22, 2017: European Journal of Pharmaceutical Sciences
Andrew I McNab, Tom Heinze, Alan J McCue, Davide Dionisi, James A Anderson
Absorption coefficients for the asymmetric stretching modes of CH3 and CH2 groups formed by adsorbing alkyl chained species from the vapour phase onto two different adsorbents; a γ-alumina support material and a supported metal catalyst have been determined using a custom made thermogravimetric-infrared cell. Results show that despite variations in the individually calculated absorption coefficients (ca. ±20%), the ratio of the absorption coefficients (CH2:CH3) remained consistent despite employing adsorbates of varying chain length and functionality, and despite the choice of adsorbents which exhibited different surface areas and light scattering characteristics...
March 16, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Zhihua Xie, Yannick Lefier, Miguel Angel Suarez, Mathieu Mivelle, Roland Salut, Jean-Marc Merolla, Thierry Grosjean
Colloidal quantum dots (CQDs) have drawn strong interest in the past for their high prospects in scientific, medical, and industrial applications. However, the full characterization of these quantum emitters is currently restricted to the visible wavelengths, and it remains a key challenge to optically probe single CQDs operating in the infrared spectral domain, which is targeted by a growing number of applications. Here, we report the first experimental detection and imaging at room temperature of single infrared CQDs operating at telecommunication wavelengths...
March 24, 2017: Nano Letters
Mi-Lan Kang, Se-Young Jeong, Gun-Il Im
Synthetic hyaluronic acid (HA) containing a covalently integrated drug is capable of releasing therapeutic molecules and is an attractive candidate for the intra-articular treatment of osteoarthritis (OA). Herein, self-assembled PEGylated kartogenin (PEG/KGN) micelles consisting of hydrophilic polyethylene glycol (PEG) and hydrophobic KGN, which has been shown to induce chondrogenesis in human mesenchymal stem cells, were prepared by covalent crosslinking. HA hydrogels containing PEG/KGN micelles (HA/PEG/KGN) were prepared by covalently bonding PEG chains to HA...
March 24, 2017: Tissue Engineering. Part A
Mohammad Javad Mokhtari, Fatemeh Koohpeima, Hadi Mohammadi
To date, high mortality in women due to malignancy breast cancer related to the metastasis to the bone is a significant challenge. Since, magnetic nanoparticles (MNPs) conjugated with the biocompatible polymers was employed for the delivery of some hydrophobic anti-cancer agents, so the main aim of the current research was to assess whether cisplatin-loaded MNPs enhanced the anti-cancer effect of free cisplatin in breast cancer cells.MNPs decorated with PEG were synthesized by an improved co-precipitation technique, and then cisplatin was loaded onto the MNPs via a simple mixing method...
March 24, 2017: Chemical Biology & Drug Design
J Barbaric, R Abbott, P Posadzki, M Car, L H Gunn, A M Layton, A Majeed, J Car
We undertook a Cochrane review of randomized controlled trials (RCTs) evaluating the effects of light-based interventions for acne vulgaris. We searched the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, ISI Web of Science, and grey literature sources (September 2015). We used the Grading of Recommendations Assessment, Development and Evaluation Working Group approach to assess the quality of evidence (QE). We included 71 RCTs (4211 participants, median sample size 31). Results from a single study (n = 266, low QE) showed little or no difference in effectiveness on participants' assessment of improvement between 20% aminolevulinic acid (ALA) photodynamic therapy (PDT), activated by blue light, versus vehicle plus blue light, whereas another study (n = 180) of a comparison of ALA-PDT (red light) concentrations showed 20% ALA-PDT was no more effective than 15%, but better than 10% and 5% ALA-PDT...
March 24, 2017: British Journal of Dermatology
Yann Bernhard, Bertrand Collin, Richard A Decréau
Cherenkov Radiation (CR), this blue glow seen in nuclear reactors, is an optical light originating from energetic β-emitter radionuclides. CR emitter (90)Y triggers a cascade of energy transfers in the presence of a mixed population of fluorophores (which each other match their respective absorption and emission maxima): Cherenkov Radiation Energy Transfer (CRET) first, followed by multiple Förster Resonance Energy transfers (FRET): CRET ratios were calculated to give a rough estimate of the transfer efficiency...
March 24, 2017: Scientific Reports
F Pelayo García de Arquer, Xiwen Gong, Randy P Sabatini, Min Liu, Gi-Hwan Kim, Brandon R Sutherland, Oleksandr Voznyy, Jixian Xu, Yuangjie Pang, Sjoerd Hoogland, David Sinton, Edward Sargent
Quantum dot and well architectures are attractive for infrared optoelectronics, and have led to the realization of compelling light sensors. However, they require well-defined passivated interfaces and rapid charge transport, and this has restricted their efficient implementation to costly vacuum-epitaxially grown semiconductors. Here we report solution-processed, sensitive infrared field-emission photodetectors. Using quantum-dots-in-perovskite, we demonstrate the extraction of photocarriers via field emission, followed by the recirculation of photogenerated carriers...
March 24, 2017: Nature Communications
Nelson A M Pereira, Mafalda Laranjo, João Casalta-Lopes, Arménio C Serra, Marta Piñeiro, João Pina, J Sérgio Seixas de Melo, Mathias O Senge, M Filomena Botelho, Liliana Martelo, Hugh D Burrows, Teresa M V D Pinho E Melo
Novel near-infrared luminescent compounds based on platinum(II) 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-fused chlorins are described. These compounds have high photostability and display light emission, in particular simultaneous fluorescence and phosphorescence emission in solution at room temperature, in the biologically relevant 700-850 nm red and near-infrared (NIR) spectral region, making them excellent materials for biological imaging. The simultaneous presence of fluorescence and phosphorescence emission at room temperature, with the phosphorescence strongly quenched by oxygen whereas fluorescence remains unaffected, allows these compounds to be used as ratiometric oxygen sensors in chemical and biological media...
March 9, 2017: ACS Medicinal Chemistry Letters
Julián David Correa, Pedro Alejandro Orellana, Mónica Pacheco
The search for new optical materials capable of absorbing light in the frequency range from visible to near infrared is of great importance for applications in optoelectronic devices. In this paper, we report a theoretical study of the electronic and optical properties of hybrid structures composed of fullerenes adsorbed on graphene and on graphene nanoribbons. The calculations are performed in the framework of the density functional theory including the van der Waals dispersive interactions. We found that the adsorption of the C 60 fullerenes on a graphene layer does not modify its low energy states, but it has strong consequences for its optical spectrum, introducing new absorption peaks in the visible energy region...
March 20, 2017: Nanomaterials
Guanying Song, Zhenjiang Li, Kaihua Li, Lina Zhang, Alan Meng
In this work, SiO2/ZnO composite hollow sub-micron fibers were fabricated by a facile single capillary electrospinning technique followed by calcination, using tetraethyl orthosilicate (TEOS), polyvinylpyrrolidone (PVP) and ZnO nanoparticles as raw materials. The characterization results of the scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) spectra indicated that the asprepared composite hollow fibers consisted of amorphous SiO2 and hexagonal wurtzite ZnO...
February 24, 2017: Nanomaterials
Li-Na Qiao, Huan-Chun Wang, Yang Shen, Yuan-Hua Lin, Ce-Wen Nan
A novel Cu1.8Se/Cu₃Se₂ composite photocatalyst was prepared by the simple precipitation method. This composite possesses a wide photoabsorption until the range of near-infrared light, and exhibits significantly enhanced photocatalytic activity for methyl orange degradation under visible and near-infrared light irradiation compared with bare Cu1.8Se and Cu₃Se₂. The mechanism of this outstanding photocatalytic behavior can be explained by the calculated energy band positions. The efficient charge separation via a phase junction of Cu1...
January 18, 2017: Nanomaterials
Prathap Pathi, Akshit Peer, Rana Biswas
Thick wafer-silicon is the dominant solar cell technology. It is of great interest to develop ultra-thin solar cells that can reduce materials usage, but still achieve acceptable performance and high solar absorption. Accordingly, we developed a highly absorbing ultra-thin crystalline Si based solar cell architecture using periodically patterned front and rear dielectric nanocone arrays which provide enhanced light trapping. The rear nanocones are embedded in a silver back reflector. In contrast to previous approaches, we utilize dielectric photonic crystals with a completely flat silicon absorber layer, providing expected high electronic quality and low carrier recombination...
January 13, 2017: Nanomaterials
Jayachandran Venkatesan, Se-Kwon Kim, Min Suk Shim
Green synthesis of silver nanoparticles (AgNPs) has gained great interest as a simple and eco-friendly alternative to conventional chemical methods. In this study, AgNPs were synthesized by using extracts of marine algae Ecklonia cava as reducing and capping agents. The formation of AgNPs using aqueous extract of Ecklonia cava was confirmed visually by color change and their surface plasmon resonance peak at 418 nm, measured by UV-visible spectroscopy. The size, shape, and morphology of the biosynthesized AgNPs were observed by transmission electron microscopy and dynamic light scattering analysis...
December 6, 2016: Nanomaterials
Sadia Saif, Arifa Tahir, Tayyaba Asim, Yongsheng Chen
Research on green production methods for metal oxide nanoparticles (NPs) is growing, with the objective to overcome the potential hazards of these chemicals for a safer environment. In this study, facile, ecofriendly synthesis of copper oxide (CuO) nanoparticles was successfully achieved using aqueous extract of Pterospermum acerifolium leaves. P. acerifolium-fabricated CuO nanoparticles were further characterized by UV-Visible spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS)...
November 9, 2016: Nanomaterials
Xiaojun Tao, Yongchao Xie, Qiufang Zhang, Ximin Qiu, Liming Yuan, Yi Wen, Min Li, Xiaoping Yang, Ting Tao, Minghui Xie, Yanwei Lv, Qinyi Wang, Xing Feng
To search for nano-drug preparations with high efficiency in tumor treatment, we evaluated the drug-loading capacity and cell-uptake toxicity of three kinds of nanoparticles (NPs). Pullulan was grafted with ethylenediamine and hydrophobic groups to form hydrophobic cholesterol-modified amino-pullulan (CHAP) conjugates. Fourier transform infrared spectroscopy and nuclear magnetic resonance were used to identify the CHAP structure and calculate the degree of substitution of the cholesterol group. We compared three types of NPs with close cholesterol hydrophobic properties: CHAP, cholesterol-modified pullulan (CHP), and cholesterol-modified carboxylethylpullulan (CHCP), with the degree of substitution of cholesterol of 2...
September 8, 2016: Nanomaterials
Wenbin Liu, Jianfa Zhang, Zhihong Zhu, Xiaodong Yuan, Shiqiao Qin
In this paper, anisotropic graphene plasmonic structures are explored for light trapping and absorption enhancement in surrounding media. It is shown that electrically tunable and versatile spectral and polarization selectivity can be realized. Particularly, it is possible to control absorption of the incident light's polarization component at a specific wavelength by varying the Fermi energy with suitable geometric designs. It may find applications for new types of infrared and THz photodetectors and will promote the research of other novel polarization devices...
August 23, 2016: Nanomaterials
Yangyang Zhao, Jing Zhao, Guiye Shan, Dongmei Yan, Yanwei Chen, Yichun Liu
It is important to control drug release and detect the distribution of drug molecules before and after release. In this work, liposome@AgAu nanocomposite is prepared for drug delivery, which not only can control drug release by near infrared laser irradiation but also can monitor drug molecules by surface enhanced Raman scattering (SERS) and fluorescence signal during the release process. The liposome@AgAu core/shell nanocomposite prepared by the galvanic replacement reaction (GRR) shows tunable localized surface plasmon resonance (LSPR) absorption peaks from visible to near-infrared region and good biocompatibility...
March 8, 2017: Colloids and Surfaces. B, Biointerfaces
Bangbang Li, Peng Zhang, Jianwei Du, Xiao Zhao, Youxiang Wang
Multifunctional nanoprobe was drawing increased attention in tumor diagnosis and therapy. The simple and effective establishment of the theranostic nanoplatforms was still under urgent need. Meanwhile, the targeting ability and morphology of nanoprobe were essential for the effective endocytosis, which could further affect the diagnosis. In this work, two morphologies of nanoprobes were fabricated using gold nanorods (AuNRs) and gold nanospheres (AuNSs). Thiolated-hyaluronic acid labeled with nile blue (HS-HA-NB), a near-infrared (NIR) fluorescence dye, was coated on the surface of the gold nanoparticles to form stable nanoprobes (AuNR@HS-HA-NB, AuNS@HS-HA-NB)...
March 9, 2017: Colloids and Surfaces. B, Biointerfaces
Claudia Woess, Seraphin Hubert Unterberger, Clemens Roider, Monika Ritsch-Marte, Nadin Pemberger, Jan Cemper-Kiesslich, Petra Hatzer-Grubwieser, Walther Parson, Johannes Dominikus Pallua
Due to the influence of many environmental processes, a precise determination of the post-mortem interval (PMI) of skeletal remains is known to be very complicated. Although methods for the investigation of the PMI exist, there still remains much room for improvement. In this study the applicability of infrared (IR) microscopic imaging techniques such as reflection-, ATR- and Raman- microscopic imaging for the estimation of the PMI of human skeletal remains was tested. PMI specific features were identified and visualized by overlaying IR imaging data with morphological tissue structures obtained using light microscopy to differentiate between forensic and archaeological bone samples...
2017: PloS One
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