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Photo sensitivity

Yaqi Mei, Qiong Hu, Baojing Zhou, Yonghui Zhang, Minhui He, Ting Xu, Feng Li, Jinming Kong
Simple and fast detection of alkaline phosphatase (ALP) activity is of great importance for diagnostic and analytical applications. In this work, we report a turn-off approach for the real-time detection of ALP activity on the basis of the charge transfer induced fluorescence quenching of the Cu(BCDS)2(2-) (BCDS = bathocuproine disulfonate) probe. Initially, ALP can enzymatically hydrolyze the substrate ascorbic acid 2-phosphate to release ascorbic acid (AA). Subsequently, the AA-mediated reduction of the Cu(BCDS)2(2-) probe, which displays an intense photoluminescence band at the wavelength of 402nm, leads to the static quenching of fluorescence of the probe as a result of charge transfer...
January 1, 2018: Talanta
Jeong Soo Kim, Byung-Man Kim, Un-Young Kim, HyeonOh Shin, Jung Seung Nam, Deok-Ho Roh, Tae-Hyuk Kwon
We developed three types of dithieno[3,2-b;2',3'-d]thiophene (DTT)-based organic sensitizers for high-performance thin photoactive TiO2 films and investigate the simple but powerful molecular engineering of different types of bonding between the triarylamine electron donor and the conjugated DTT π-bridge by the introduction of single, double, and triple bonds. As a result, with only 1.3-μm transparent and 2.5-μm TiO2 scattering layers, the triple bond sensitizer (T-DAHTDTT) shows the highest power conversion efficiency (η = 8...
September 15, 2017: ACS Applied Materials & Interfaces
Melike Karakus, Wen Zhang, Hans Joachim Räder, Mischa Bonn, Enrique Cánovas
The long-term stability of dye sensitized solar cells (DSSCs) is determined to a large extent by the photodegradation of their sensitizers. Understanding the mechanism of light induced decomposition of dyes sensitizing a mesoporous oxide matrix may therefore contribute to solutions to increase the life span of DSSCs. Here, we investigate, using ultrafast terahertz photoconductivity measurements, the evolution of interfacial electron transfer (ET) dynamics in N3 dye-sensitized mesoporous TiO2 electrodes upon dye photodegradation...
September 15, 2017: ACS Applied Materials & Interfaces
Tushar Dhanani, Raghuraj Singh, Satyanshu Kumar
The objective of the present investigation was to optimize extraction conditions for maximum recovery of bioactive phenolics from different parts of Saraca asoca. Extraction recovery was optimized using a mixture of methanol and water in different proportions. For identification and quantification of six analytes, a rapid reversed phase ultra-performance liquid chromatography (UPLC) photo diode array detection method was developed. UPLC separation was achieved in a gradient elution mode on a C18 column with acetonitrile and aqueous phosphoric acid (0...
July 2017: Journal of Food and Drug Analysis
Yohei Yamauchi, Yumiko Kanzaki, Masuo Hayashi, Mami Arai, Hideaki Morita, Tsuyoshi Komori, Masaaki Hoshiga, Nobukazu Ishizaka
BACKGROUND: Attenuation correction using segmentation of scatter and photo-peak window data (SSPAC) enables an evaluation of the attenuation map in a patient-specific manner without additional radiation exposure. We compared the accuracy of SSPAC and non-corrected myocardial perfusion scintigraphy methods for diagnosing the number of stenosed coronary artery vessels. METHODS AND RESULTS: We retrospectively reviewed the data from 183 consecutive patients who underwent (99m)Tc-tetrofosmin stress/rest SPECT examination and a coronary angiography within 3 months...
September 13, 2017: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
Guolin Ma, Shufan Wen, Yun Huang, Yubin Zhou
Ca(2+) signals regulate a plethora of cellular functions that include muscle contraction, heart beating, hormone secretion, lymphocyte activation, gene expression, and metabolism. To study the impact of Ca(2+) signals on biological processes, pharmacological tools and caged compounds have been commonly applied to induce fluctuations of intracellular Ca(2+) concentrations. These conventional approaches, nonetheless, lack rapid reversibility and high spatiotemporal resolution. To overcome these disadvantages, we and others have devised a series of photoactivatable genetically encoded Ca(2+) actuators (GECAs) by installing light sensitivities into a bona fide highly selective Ca(2+) channel, the Ca(2+) release-activated Ca(2+) (CRAC) channel...
2017: Advances in Experimental Medicine and Biology
Zheng Qi Bai, Ze Wen Liu
A broadband photodetector has been developed on the basis of ZnO nanowires (NWs)/Rhodamine B (RhB) hybrid system. The device is fabricated by spraying NWs on to gold interdigital electrodes followed by modifying the NWs via an RhB solution-casting process. Measurements show that the as-fabricated device demonstrates photoresponsivity ranging from 300 nm to 700 nm with a bandwidth as large as 400 nm. The role of the dye sensitizer adsorbed on the surface of NWs is modeled to alter the transportation path of photo-generated carriers...
September 12, 2017: Scientific Reports
Ping Hou, Na Zhang, Ruxia Wu, Weiwei Xu, Zhaosheng Hou
In this paper, a novel kind of photo-cross-linked biodegradable hydrogels based on n-arm-poly(ethylene glycol) ( n = 2, 3, and 4) and poly(ɛ-caprolactone) was prepared by ultraviolet-initiated free radical polymerization. The resulting n-arm-poly(ethylene glycol)-poly(ɛ-caprolactone) and n-arm-poly(ethylene glycol)-poly(ɛ-caprolactone) acrylate (n-arm-PEG-PCL-AC, macromer) were characterized by proton nuclear magnetic resonance and fourier transform infrared spectra. The influences of arm numbers and concentration of macromer on the properties of hydrogel were researched systematically, and the results showed that the gelation time, equilibrium swelling ratio, in vitro degradation, and drug release rate decreased with the increase of arm numbers and concentration of macromer...
January 1, 2017: Journal of Biomaterials Applications
Ricardo Enrique Alvarado, Hoang Thanh Nguyen, Brigitte Pépin-Donat, Christian Lombard, Yoann Roupioz, Loïc Leroy
Protein surface patterning is employed in a broad spectrum of applications ranging from protein micro-array analysis to 2D cell organization. However, limitations arise due to the highly sensitive nature of proteins requiring careful handling to ensure their structural and functional integrity during the grafting process. Here we describe a patterning protocol that keeps proteins in an aqueous environment during their immobilization, avoiding loss of their biological activity. The procedure is based on the UV-mediated removal of Poly-Ethylene Glycol (PEG) Self-Assembled Monolayers (SAMs) in a transparent microfluidic chamber, giving access to micrometric motifs of predefined geometries...
September 13, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Daniel J Carbaugh, Sneha G Pandya, Jason T Wright, Savas Kaya, Faiz Rahman
We describe techniques for performing photolithography and electron beam lithography in succession on the same resist-covered substrate. Larger openings are defined in the resist film through photolithography whereas smaller openings are defined through conventional electron beam lithography. The two processes are carried out one after the other and without an intermediate wet development step. At the conclusion of the two exposures, the resist film is developed once to reveal both large and small openings...
September 12, 2017: Nanotechnology
Meingold H M Chan, Chia-Huei Tseng
Contagious yawning-the urge to yawn when thinking about, listening to, or viewing yawning-is a well-documented phenomenon in humans and animals. The reduced yawn contagion observed in the autistic population suggested that it might be empathy related; however, it is unknown whether such a connection applies to nonclinical populations. We examined influences from both empathy (i.e., autistic traits) and nonempathy factors (i.e., individuals' perceptual detection sensitivity to yawning, happy, and angry faces) on 41 nonclinical adults...
July 2017: I-Perception
Richard B Cooley, Holger Sondermann
Fundamental to all living organisms is the ability of proteins to interact with other biological molecules at the right time and location, with the proper affinity, and to do so reversibly. One well-established technique to study protein interactions is chemical cross-linking, a process in which proteins in close spatial proximity are covalently tethered together. An emerging technology that overcomes many limitations of traditional cross-linking methods is one in which photoactivatable cross-linking noncanonical amino acids are genetically encoded into a protein of interest using the cell's native translational machinery...
2017: Methods in Molecular Biology
Nishanthan Ramachandran, Hong Sheng Chiong, Mary Jane Sime, Graham A Wilson
Importance There is a burgeoning interest in the use of deep neural network in diabetic retinal screening. BACKGROUND: To determine whether a deep neural network could satisfactorily detect diabetic retinopathy that requires referral to an ophthalmologist from a local diabetic retinal screening programme and an international database. Design Retrospective audit Samples Diabetic retinal photos from Otago database photographed during October 2016 (485 photos); and 1200 photos from Messidor international database...
September 7, 2017: Clinical & Experimental Ophthalmology
Cansu Ergene, Edmund F Palermo
Self-immolative polymers (SIMPs) are macromolecules that spontaneously undergo depolymerization into small molecules when triggered by specific external stimuli. We report here the first examples of antimicrobial SIMPs with potent, rapid, broad-spectrum bactericidal activity. Their antibacterial and hemolytic activities are examined as a function of cationic functionality. Polymers bearing primary ammonium cationic groups showed more potent bactericidal activity against E. coli, relative to tertiary and quaternary ammonium counterparts, whereas the quaternary ammonium polymers showed the lowest hemolytic toxicity...
September 7, 2017: Biomacromolecules
Minako Wakasugi, Junichiro James Kazama, Kazuko Kawamura, Suguru Yamamoto, Masaaki Nagai, Kentaro Omori, Saori Yokota, Hirokazu Fujikawa, Ikuo Aoike, Tsukasa Omori, Ichiei Narita
Earlobe creases are surrogate markers for high risk of cardiovascular disease. There is no data concerning earlobe creases among hemodialysis patients, who have an increased risk of cardiovascular disease. A cross-sectional study was conducted to determine the prevalence of earlobe creases and their association with prevalent cardiovascular disease among hemodialysis patients. Patients undergoing hemodialysis were recruited from five outpatient hemodialysis centers. Both earlobes were photographed during a dialysis session with the patient in a supine position and the photos evaluated independently by two experienced nephrologists blinded to the participants' clinical characteristics...
September 7, 2017: Therapeutic Apheresis and Dialysis
Bing Yu, Hailin Cong, Zhen Yang, Shujing Yang, Yuezhong Wang, Feng Zhai, Yifan Wang
Humidity-sensitive poly(ethylene glycol) (PEG) inverse opals with micropatterns of 2 μm wide anti-swell-broken grooves were prepared using polystyrene (PS) colloidal crystals as templates and colloidal lithography. Monodisperse PS colloids were deposited in an ordered manner onto glass slides using a double-substrate vertical deposition method to form colloidal crystal templates. Poly(ethylene glycol) diacrylate (PEGDA) with photoinitiator was infiltrated into the interspaces of the colloidal crystals and photo-crosslinked by UV irradiation through a photomask...
September 5, 2017: Materials
Anne-Helen Lutter, Jenny Scholka, Heiko Richter, Ursula Anderer
BACKGROUND: Tetrazolium-based assays are optimized to assess proliferation/toxicity of monolayer or suspension cells in microtiter plates. With regard to tissue engineering and regenerative medicine the need for in vivo like 3D microtissues has an increasing relevance. Applying tetrazolium-based assays to 3D culture systems is technically more challenging. The composed microenvironment may influence the assay standards, e.g. equal distribution of tetrazolium. OBJECTIVE: Evaluation of membrane-impermeable tetrazolium salt-based assays with regard to spheroid culture (3D) of human chondrocytes...
August 28, 2017: Clinical Hemorheology and Microcirculation
Spyros Foteinis, Jose Maria Monteagudo, Antonio Durán, Efthalia Chatzisymeon
The environmental sustainability of a semi-industrial solar photo-Fenton reactor, treating real effluents emanating from a pharmaceutical laboratory, is assessed herein. The life cycle assessment/analysis (LCA) methodology was employed and real life cycle inventory (LCI) data was collected from a ferrioxalate-assisted homogeneous solar photo-Fenton wastewater treatment plant (WWTP), at Ciudad Real, Spain. Electricity was provided by photovoltaic (PV) panels in tandem with a battery bank, making the plant autonomous from the local grid...
August 31, 2017: Science of the Total Environment
P Pinot, Z Silvestri
This paper presents a preliminary study of an elementary device consisting of a small plate made from pyrolytic carbon levitated above a magnet array which is sensitive to any irradiating laser power. This device might provide an interesting alternative to power meters based on thermal measurement techniques via the Stefan-Boltzmann law or the photon-electron interaction. We show that the photo-response of a pyrolytic carbon plate in terms of levitation height versus irradiation power in the range of 20 mW to 1 W is sufficiently linear, sensitive, and reproducible to be used as a laser power sensor...
August 2017: Review of Scientific Instruments
Marc Robert, Heng Rao, Julien Bonin
We used an iron substituted tetraphenyl porphyrin bearing positively charged trimethylammonio groups at the para position of each phenyl ring for the photoinduced conversion of CO2. This complex is water soluble and acts as a molecular catalyst to selectively reduce CO2 into CO under visible light irradiation in aqueous solutions (acetonitrile:water 1:9 v:v) with the assistance of purpurin, a simple organic photosensitizer. CO is produced with a catalytic selectivity of 95% and turnover up to 120, illustrating the possibility of photo-catalysing the reduction of CO2 in aqueous solution using visible light, a simple organic sensitizer coupled to an amine as sacrificial electron donor and an earth abundant metal based molecular catalyst...
September 1, 2017: ChemSusChem
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