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Yuqing Dong, Guorui Jin, Changchun Ji, Rongyan He, Min Lin, Xin Zhao, Ang Li, Tian Jian Lu, Feng Xu
Tracking the distribution and degradation of hydrogels in vivo is important for various applications including tissue engineering and drug delivery. Among various imaging modalities, fluorescence imaging has attracted intensive attention due to their high sensitivity, low cost and easy operation. Particularly, upconversion nanoparticles (UCNPs) that emit visible lights upon near-infrared (NIR) light excitation as tracking probes are promising in deciphering the fate of hydrogels after transplantation. Herein, we reported a facile and non-invasive in vivo hydrogel tracking method using UCNPs, where the degradation of hydrogels was determined using the decrease in fluorescence intensity from the UCNPs encapsulated in the hydrogels...
April 17, 2017: Acta Biomaterialia
Lu Wei, Zhixing Chen, Lixue Shi, Rong Long, Andrew V Anzalone, Luyuan Zhang, Fanghao Hu, Rafael Yuste, Virginia W Cornish, Wei Min
The ability to visualize directly a large number of distinct molecular species inside cells is increasingly essential for understanding complex systems and processes. Even though existing methods have successfully been used to explore structure-function relationships in nervous systems, to profile RNA in situ, to reveal the heterogeneity of tumour microenvironments and to study dynamic macromolecular assembly, it remains challenging to image many species with high selectivity and sensitivity under biological conditions...
April 19, 2017: Nature
Christopher A Broderick, Shirong Jin, Igor P Marko, Konstanze Hild, Peter Ludewig, Zoe L Bushell, Wolfgang Stolz, Judy M Rorison, Eoin P O'Reilly, Kerstin Volz, Stephen J Sweeney
The potential to extend the emission wavelength of photonic devices further into the near- and mid-infrared via pseudomorphic growth on conventional GaAs substrates is appealing for a number of communications and sensing applications. We present a new class of GaAs-based quantum well (QW) heterostructure that exploits the unusual impact of Bi and N on the GaAs band structure to produce type-II QWs having long emission wavelengths with little or no net strain relative to GaAs, while also providing control over important laser loss processes...
April 19, 2017: Scientific Reports
Zachary A Vesoulis, Amit M Mathur
Improvements in clinical management of the preterm infant have reduced the rates of the two most common forms of brain injury, such as severe intraventricular hemorrhage and white matter injury, both of which are contributory factors in the development of cerebral palsy. Nonetheless, they remain a persistent challenge and are associated with a significant increase in the risk of adverse neurodevelopment outcomes. Repeated episodes of ischemia-reperfusion represent a common pathway for both forms of injury, arising from discordance between systemic blood flow and the innate regulation of cerebral blood flow in the germinal matrix and periventricular white matter...
2017: Frontiers in Pediatrics
Hongseung Yeon, Chenxuan Wang, Reid Van Lehn, Nicholas L Abbott
We report an experimental investigation of the influence of molecular-level order (crystallinity) within non-polar monolayers on hydrophobic interactions. The measurements were performed using gold film-supported monolayers formed from alkanethiols (CH3(CH2)nSH, with n ranging from 3 to 17), which we confirmed by using polarization-modulation infrared reflection-adsorption spectroscopy to exhibit chain-length-dependent order (methylene peak moves from 2926 to 2919 cm-1, corresponding to a transition from liquid- to quasi-crystalline-like order) in the absence of substantial changes in chain-density (constant methyl peak intensity)...
April 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Rizwan Ali Naqvi, Muhammad Arsalan, Kang Ryoung Park
Gaze-based interaction (GBI) techniques have been a popular subject of research in the last few decades. Among other applications, GBI can be used by persons with disabilities to perform everyday tasks, as a game interface, and can play a pivotal role in the human computer interface (HCI) field. While gaze tracking systems have shown high accuracy in GBI, detecting a user's gaze for target selection is a challenging problem that needs to be considered while using a gaze detection system. Past research has used the blinking of the eyes for this purpose as well as dwell time-based methods, but these techniques are either inconvenient for the user or requires a long time for target selection...
April 14, 2017: Sensors
Zigui Kan, Qiang Zhu, Lijiang Yang, Zhixiong Huang, Biao-Bing Jin, Jing Ma
Conformation of cellulose with various degree of polymerization of n = 1~12 in ionic liquid 1,3-dimethylimidazolium chloride ([C1mim]Cl) and the intermolecular interaction between them were studied by means of molecular dynamics (MD) simulations with fixed-charge and charge variable polarizable force fields, respectively. The integrated tempering enhanced sampling method was also employed in the simulations in order to improve the sampling efficiency. Cellulose undergoes significant conformational changes from a gaseous right-hand helical twist along the long axis to a flexible conformation in ionic liquid...
April 18, 2017: Journal of Physical Chemistry. B
Jiaoliang Wang, Liping Long, Li Xia, Fang Fang
A near-infrared fluorescent probe NIR-Hg ,for detection of Hg2+ ion, has been synthesized directly by condensing Changsha dye with 4-Phenyl-3-thiosemicarbazide and the structure has fully characterized by 1HNMR, 13CNMR, and ESI-MS. The probe has been designed, on the basis of the reaction that Hg2+ ion promotes thiosemicarbazide to oxazole in aqueous media and had been induced to produce turn-on fluorescence via an irreversible spirolactam ring-opening process. The probe NIR-Hg has exhibited fast response (1 min), high sensitivity with 44-fold fluorescence intensity enhancement under 6 equivalent of Hg2+ added, high selectivity over other related metal ions and the low detection limit of 5...
April 18, 2017: Methods and Applications in Fluorescence
Alexander Bauer, Otto Hertzberg, Arne Küderle, Dominik Strobel, Miguel A Pleitez, Werner Mäntele
We have reported two methods to analyze glucose in the interstitial fluid of skin based on mid-infrared excitation with a tunable quantum cascade laser and photoacoustic or photothermal detection. These methods were evaluated for optimum skin locations to obtain reproducible glucose information. The lower part of the arm, the hypothenar, the tips of the index finger and the thumb were tested. The thumb appears to be the optimal skin location, followed by the index finger. Basic requirements for an optimum site are good capillary blood perfusion, low Stratum corneum thickness and the absence of fat layers...
April 18, 2017: Journal of Biophotonics
Jorge Medina, Carlos Monreal, Denise Chabot, Sebastián Meier, María Eugenia González, Esteban Morales, Rita Parillo, Fernando Borie, Pablo Cornejo
We characterized humic substances (HS) extracted from a Cu-contaminated soil without compost addition (C) or amended with a wheat straw-based compost (WSC) (H1), co-composted with Fe2O3 (H2), or co-composted with an allophane-rich soil (H3). Extracted HS were characterized under electron microscopy (SEM/TEM), energy-dispersive X-ray (X-EDS), and Fourier transform infrared (FTIR) spectroscopy. In addition, HS extracted from WSC (H4) were characterized at pH 4.0 and 8.0 with descriptive purposes. At pH 4.0, globular structures of H4 were observed, some of them aggregating within a large network...
April 17, 2017: Environmental Science and Pollution Research International
António Jorge Lopes Jesus, Rui Fausto, Igor Reva
The molecule of 5-methoxyindole (5MOI) may adopt two conformational states, syn and anti, with respect to the relative orientation of the NH and OCH3 groups. Structure of monomeric 5MOI was characterized spectroscopically, in mid- and near-infrared domains. The conformational composition of 5MOI could be controlled in three different ways. Thermally, two conformers of 5MOI could be trapped in xenon matrixes at 16 K. Upon annealing the xenon matrix to temperatures about 30-40 K, the higher energy syn form converted to the ground state anti conformer...
April 14, 2017: Journal of Physical Chemistry. A
Rishabh Jain, Reza Abbasi, Kevin Nelson, David Busche, David M Lynn, Nicholas L Abbott
We report that thin films of solid sodium chlorite (NaClO2) can be photochemically activated by irradiation with ultraviolet (UV) light to generate gaseous chlorine dioxide (ClO2) upon subsequent exposure to moisture. The limiting role of water in the reaction is evidenced by an increase in yield of ClO2 with relative humidity of the gas stream passed over the UV-activated salt. The UV-activated state of the NaClO2 was found to possess a half-life of 48 hours, revealing the presence of long-lived UV activated species that subsequently react with water to produce gaseous ClO2...
April 14, 2017: ACS Applied Materials & Interfaces
Ajanta Barh, Christian Pedersen, Peter Tidemand-Lichtenberg
In this Letter, we demonstrate efficient room temperature detection of ultra-broadband mid-wave-infrared (MWIR) light with an almost flat response over more than 1200 nm, exploiting an efficient nonlinear upconversion technique. Black-body radiation from a hot soldering iron rod is used as the IR test source. Placing a 20 mm long periodically poled lithium niobate crystal in a compact intra-cavity setup (>20  W CW pump at 1064 nm), MWIR wavelengths ranging from 3.6 to 4.85 μm are upconverted to near-infrared (NIR) wavelengths (820-870 nm)...
April 15, 2017: Optics Letters
Atsuto Onoda, Takayasu Kawasaki, Koichi Tsukiyama, Ken Takeda, Masakazu Umezawa
Environmental stimulation during brain development is an important risk factor for the development of neurodegenerative disease. Clinical evidence indicates that prenatal exposure to particulate air pollutants leads to diffuse damage to the neurovascular unit in the developing brain and accelerates neurodegeneration. Maternal exposure to carbon black nanoparticles (CB-NPs), used as a model for particulate air pollution, induces long-lasting diffuse perivascular abnormalities. We aimed to comprehensively characterize the perivascular abnormalities related to maternal NPs exposure using Fourier transform infrared microspectroscopy (in situ FT-IR) and classical staining analysis...
2017: Frontiers in Cellular Neuroscience
Shin-Ichiro Inoue, Nozomi Iwashita, Yohei Takahashi, Eiji Gotoh, Eiji Okuma, Maki Hayashi, Ryohei Tabata, Atsushi Takemiya, Yoshiyuki Murata, Michio Doi, Toshinori Kinoshita, Ken-Ichiro Shimazaki
Stomata within the plant epidermis regulate CO2 uptake for photosynthesis and water loss through transpiration. Stomatal opening in Arabidopsis thaliana is determined by various factors, including blue light as a signal and multiple phytohormones. Plasma membrane transporters, including H+-ATPase, K+ channels, and anion channels in guard cells mediate these processes, and the activities and expression levels of these components determine stomatal aperture. However, the regulatory mechanisms involved in these processes are not fully understood...
April 12, 2017: Plant & Cell Physiology
Xiao-Yang Liu, Wei Chen, Chen Qian, Han-Qing Yu
The production and use of ionic liquids (ILs) increase the potential risk after their emission into the environment. After entering the environment, ILs will readily interact with dissolved organic matter (DOM), and their environmental behavior will be impacted by DOM, which is abundant in the environment and has various functional groups. However, to date, the interaction between DOM and ILs, especially long-chain ILs, remains unclear. In this work, the interaction between long-chain ILs and humic acid (HA), a representative DOM, was investigated using synchronous fluorescence, Fourier transform infrared spectroscopy, dynamic light scattering and zeta potential techniques, which were integrated with two-dimensional correlation spectroscopy (2DCOS), hetero-2DCOS and perturbation-correlation moving-window analyses...
April 13, 2017: Environmental Science & Technology
Zhipeng He, Tingting Zhao, Xiaofeng Zhou, Zhao Liu, He Huang
Whether the process of protein folding/unfolding is fully cooperative or it contains sequential elements has long been a fundamental issue in protein science. This issue seemingly became straightforward since the appearance of generalized two-dimensional (2D) correlation spectroscopy in 1990s, because 2D correlation analysis has been considered as a convenient and powerful analytical tool to determine the sequential order of events under external physical or chemical perturbations. In this work, the sequential order of the secondary structure transitions of regenerated silk fibroin under thermal treatment from 130 to 220 oC was first studied using generalized 2D correlation spectroscopy, but an apparently doubtful sequential order was obtained; β-sheet was the first one to change at low temperature, then the random coil, followed by the non-amide C=O, and finally the α-helix...
April 13, 2017: Analytical Chemistry
Xiaoyun Chen, Qing Min Wang, Luke Bu
A two-step synthesis of polyimide reaction from dianhydride and diamine was followed by both infrared (IR) and Raman spectroscopy in situ in this case study. In the first step, the two reactants form poly(amide acid), which resulted in substantial spectral changes easily detected by both spectroscopic techniques. The reaction was found to occur rapidly and reached completion within tens of minutes at room temperature. In the second step, trimethylamine (catalyst) and acetic anhydride (dehydration agent) were added to form the five-member imide ring...
January 1, 2017: Applied Spectroscopy
Yu Wang, Xue Bai, Tongyu Wang, Long Yan, Tieqiang Zhang, Yu Zhang, William Yu
Recently, near-infrared light-emitting diodes (NIR LEDs) based on PbSe quantum dots (QDs) have attracted considerable attention due to their facilely tunable emission wavelength, as well as high quantum yield. However, the low external quantum efficiency (EQE) of these LEDs has restricted their actual applications because of the non-radiative recombination caused by the aggregation in the solid-state QD films. Therefore, we proposed in this work to employ the liquid-type structure in NIR LEDs base on PbSe QDs, which exhibited the main advantages relying on the fact that the liquid structure could prevent the active layer from self-aggregation and improve the device stability...
April 12, 2017: Nanotechnology
Sung Ho Jang, Jung Pyo Seo, Seung-Hyun Lee, Sang-Hyun Jin, Sang Seok Yeo
Bilateral arm raising movements have been used in brain rehabilitation for a long time. However, no study has been reported on the effect of these movements on the cerebral cortex. In this study, using functional near infrared spectroscopy (fNIRS), we attempted to investigate cortical activation generated during bilateral arm raising movements. Ten normal subjects were recruited for this study. fNIRS was performed using an fNIRS system with 49 channels. Bilateral arm raising movements were performed in sitting position at the rate of 0...
February 2017: Neural Regeneration Research
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