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Photo sensitivity

Ying Chen, Yu Li, Dongmei Deng, Haibo He, Xiaoxia Yan, Zhenxin Wang, Chunhai Fan, Liqiang Luo
A novel and sensitive sandwich immunosensor for amperometric determination of carcinoembryonic antigen (CEA) was designed using Au nanoparticles-titanium dioxide-graphene (AuNPs-TiO2-graphene) nanocomposites. Dopamine-functionalized graphene was firstly prepared by π-stacking interaction, and TiO2 was then attached to the surface of dopamine-graphene by the specificity and high affinity of enediol ligands to Ti (IV). Afterwards, AuNPs-TiO2-graphene nanocomposites were synthesized with photo-reduction approach under ultraviolet irradiation...
November 17, 2017: Biosensors & Bioelectronics
Sahar E Abo-Neima
Cancer treatment is one of the main challenges that face the scientific centers all over the world. The cancer incidence percentage increases year after year. The most used treatment for cancer is chemotherapy which is an application of systemic cytotoxic drug inside the patient. There are two main problems in chemotherapy that the cytotoxic drug is given systematically and cannot be localized in the tumor region in most cases that lead to killing the cancer cells as well as normal cells; and that cause the chemotherapy side effects like anemia, decrease in all blood cells count and platelets, nausea, vomiting, diarrhea, hair and nails loss and may cause a kind of blood toxicity...
November 14, 2017: Progress in Biophysics and Molecular Biology
Radka Vágnerová, Alena Lukešová, Martin Lukeš, Petra Rožnovská, Marcela Holá, Jana Fulnečková, Jiří Fajkus, Karel J Angelis
Research in algae usually focuses on the description and characterization of morpho-and phenotype as a result of adaptation to a particular habitat and its conditions. To better understand the evolution of lineages we characterized responses of filamentous streptophyte green algae of the genera Klebsormidium and Zygnema, and of a land plant-the moss Physcomitrellapatens-to genotoxic stress that might be relevant to their environment. We studied the induction and repair of DNA double strand breaks (DSBs) elicited by the radiomimetic drug bleomycin, DNA single strand breaks (SSB) as consequence of base modification by the alkylation agent methyl methanesulfonate (MMS) and of ultra violet (UV)-induced photo-dimers, because the mode of action of these three genotoxic agents is well understood...
November 17, 2017: Genes
Ismail Hakki Baltacioglu, Kaan Orhan
BACKGROUND: Although numerous studies have used digital intraoral imaging, only a few studies have used photo-optical methods for the diagnosis of caries. Moreover, several limitations exist in terms of observers (experience and specialty) and the caries lesion itself. Hence, the aims of this study were to evaluate the diagnostic capability of near-infrared light transillumination (NILT) and PSP-Bitewing radiographs and to compare the interobserver and intraobserver differences in addition to observers' experience level to detect early interproximal caries lesions in vivo...
November 16, 2017: BMC Oral Health
Claudia Colesie, Burkhard Büdel, Vaughan Hurry, T G Allan Green
The Antarctic Peninsula, a tundra biome dominated by lichens and bryophytes, is an ecozone undergoing rapid temperature shifts. Such changes may demand a high physiological plasticity of the local lichen species in order for them to maintain their role as key drivers in this pristine habitat. This study examines the response of net photosynthesis and respiration to increasing temperatures for three Antarctic lichen species with different ecological response amplitudes. We hypothesise that negative effects caused by increased temperatures can be mitigated by thermal acclimation of respiration and/or photosynthesis...
November 15, 2017: Global Change Biology
Murtaza Sameen, Muhammad Saim Khan, Asad Habib, Muhammad Amer Yaqub, Mazhar Ishaq
Objective: To compare post-operative pain relieving effect of topical diclofenac 0.1% versus ketorolac 0.5% in Corneal Collagen Cross Linking (CXL) for patients diagnosed with keratoconus. Methods: This randomized controlled trial was carried out for six months from October 2016 to March 2017. We included young patients having keratoconus with k-readings greater than 47D and central corneal thickness more than 400 microns. All the patients received single dose one drop of topical diclofenac 0...
September 2017: Pakistan Journal of Medical Sciences Quarterly
Jie Song, Shuo Wu, Xinlan Yang, Jingli Yuan
Graphene nanodisks with good conductivity and plenty of edge sites were synthesized to load glucose oxidase (GRD-GOD) and coupled with a Mn(2+) doped CdS quantum dot (QD) modified TiO2 electrode (CdS:Mn/TiO2) for a highly sensitive photoelectrochemical (PEC) immunoassay. The specific immune-recognition behaviour can bring the GRD-GOD labelled antigen into the antibody immobilized CdS:Mn/TiO2 interface and dramatically enhance the photocurrent response via a dual signal amplification strategy. First, graphene nanodisks with a strong electron transfer capacity can improve the conductivity of both the insulating protein layers and the CdS:Mn/TiO2 matrix, thus facilitating the regeneration of trapped carriers and hot electrons in the CdS:Mn QD films and enhancing the PEC performance...
November 15, 2017: Analyst
Brandon Hardie, Mark Roll
Polyoxometalate (POM) hybrid materials have shown potential as spin-coatable, patternable dielectric thin-films and components for lithographic resists. In particular, the octamolybdate cluster has been shown to possess good spin-coating properties and the patterning capabilities of hybrid octamolybdate thin-films were explored using a combination of broadband UV and electron beam lithography (EBL) techiniques. Dielectric properties of these films were determined by ellipsometry, and octamolybdate clusters were subsequently investigated as negative resists in various blends for potential uses in next-generation photolithography, where contrast, sensitivity, and line edge roughness characteristics were determined...
November 15, 2017: Materials
Stéphanie Mendes Marinho, Minh-Huong Ha-Thi, Van-Thai Pham, Annamaria Quaranta, Thomas Pino, Christophe Lefumeux, Thierry Chamaillé, Winfried Leibl, Ally Aukauloo
Biomimetic models that contain elements of photosynthesis are fundamental in the development of synthetic systems that can use sunlight to produce fuel. The critical task consists of running several rounds of light-induced charge separation, which is required to accumulate enough redox equivalents at the catalytic sites for the target chemistry to occur. Long-lived first charge-separated state and distinct electronic signatures for the sequential charge accumulated species are essential features to be able to track these events on a spectroscopic ground...
November 15, 2017: Angewandte Chemie
Eun Bi Kang, Cheong A Choi, Zihnil Adha Islamy Mazrad, Sung Han Kim, Insik In, Sung Young Park
The tumor-specific sensitive fluorescence sensing of cellular alkaline phosphatase (ALP) activity based on host-guest specific and pH sensitive by ere conducted on coated surfaces and aqueous states. Cross-linked fluorescent nanoparticles (C-FNP) consisting of β-cyclodextrin (β-CD)/boronic acid (BA) and fluorescent hyaluronic acid [FNP(HA)] were conjugated to fluorescent polydopamine [FNP(pDA)]. To determine the quenching effect of this system, hydrolysis of 4-nitrophenyl phosphate (NPP) to 4-nitrophenol (NP) was performed in the cavity of β-CD in the presence of ALP activated photo-induced electron transfer (PET) between NP and C-FNP...
November 15, 2017: Analytical Chemistry
Xiaofang Ma, Yali Wu, Samrat Devaramani, Caizhong Zhang, Qixia Niu, Mahgoub Ibrahim Shinger, Wenqi Li, Duoliang Shan, Xiaoquan Lu
The GO-COOH/AuNPs/ZnAPTPP nanocomposites were constructed using zinc monoamino porphyrin (ZnAPTPP) through π-π conjugation with carboxylated graphene oxide (GO-COOH) loaded with Au nanoparticles (AuNPs). Prepared materials were characterized by (1)H NMR spectra, UV-vis absorption spectroscopy and electrochemical impedance spectroscopy. ITO electrode surface was modified with the prepared nanocomposites showed a good photocurrent response when the bias potential, -0.1V was applied. Nanocomposites modified ITO electrode exhibited good photo-response to the 4-nitrophenol (4-NP)...
February 1, 2018: Talanta
Prabhat Kumar Singh, Ankur Awasthi
Photo-induced intermolecular excited-state proton transfer (ESPT) reactions are ubiquitous in chemistry and biology. ESPT reactions are extremely sensitive to the nature of water molecules in its microenvironment and thus serve as a sensitive reporter for the water structure and dynamics in a system. Herein, the photo-induced intermolecular ESPT reaction of 8-Hydroxy pyrene-1, 3, 5-trisulfonic acid (HPTS, also known as Pyranine) has been investigated in various DMSO-water mixtures using steady-state and time-resolved emission spectroscopy...
November 14, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
F Flament, R Bazin
BACKGROUND: To study capacity of skin to being imprinted by a marking head rapidly applied (10 seconds) onto the skin under a standardized pressure (15 kPa). MATERIAL AND METHODS: Referential photographs of skin markings, resulting from different times of application serve at grading the extent of skin imprints. The imprinting tool, equipped with 5 linear bulbs of different sizes but same thickness (1 mm), was applied onto the cheeks of 641 women of different ages (18-80 years) of 3 different ethnic groups...
November 12, 2017: Skin Research and Technology
Rúben F Pereira, Cristina C Barrias, Paulo J Bártolo, Pedro L Granja
Cell-instructive hydrogels are attractive for skin repair and regeneration, serving as interactive matrices to promote cell adhesion, cell-driven remodeling and de novo deposition of extracellular matrix components. This paper describes the synthesis and photocrosslinking of cell-instructive pectin hydrogels using cell-degradable peptide crosslinkers and integrin-specific adhesive ligands. Protease-degradable hydrogels obtained by photoinitiated thiol-norbornene click chemistry are rapidly formed in the presence of dermal fibroblasts, exhibit tunable properties and are capable of modulating the behavior of embedded cells, including the cell spreading, hydrogel contraction and secretion of matrix metalloproteases...
November 8, 2017: Acta Biomaterialia
Jin-Jie Hu, Xiao-Lin Bai, Yi-Ming Liu, Xun Liao
Tyrosinase (TYR) is a key enzyme in melanin biosynthesis and its activity is an important biomarker for dermatological disorders, such as vitiligo, melanoma and actinic damages. Sensitive assay for TYR activity is significant for basic and clinical research. In this work, a facile fluorescent assay for TYR activity based on dopamine functionalized carbon quantum dots (CQDs-Dopa) has been developed. Dopamine (Dopa) was covalently bond to CQDs through a simple one-pot hydrothermal method, and the prepared CQDs-Dopa exhibited a fluorescence emission at 499 nm under exciting wavelength at 310 nm with a quantum yield of approximately 2...
December 1, 2017: Analytica Chimica Acta
Xiaoqian Ge, Jinliang Liu, Lining Sun
Lanthanide-doped upconversion nanoparticles (UCNPs) can convert long wavelength excitation radiation in the near-infrared region to higher energy emission radiation from ultraviolet to near-infrared. The anti-Stokes luminescence process will result in high tissue penetration depth, low background noise and low photo-damage in bioimaging applications. Considering these excellent optical performances, UCNPs have been considered as the next generation of fluorescent probes for sensing and bioimaging based on near-infrared light stimulation...
November 10, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Veerasamy Sathish, Arumugam Ramdass, Murugesan Velayudham, Kuang-Lieh Lu, Pounraj Thanasekaran, Seenivasan Rajagopal
The detection of chemical explosives is a major area of research interest and is essential for the military as well as homeland security to counter the catastrophic effects of global terrorism. In recent years, tremendous effort has been devoted to the development of luminescent materials for the detection of explosives in the vapor, solution, and solid states with a high degree of selectivity and sensitivity and a rapid response time. Apart from the wide range of organic fluorescent chemosensors, transition metal complexes play a prominent role in the sensing of nitroaromatic explosives owing to their rich photophysical characteristics...
November 10, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Jing Lu, Xinglong Tu, Guilin Yin, Hui Wang, Dannong He
In this work, a spot laser modulated resistance switching (RS) effect is firstly observed on n-type Mn-doped ZnO/SiO2/Si structure by growing n-type Mn-doped ZnO film on Si wafer covered with a 1.2 nm native SiO2, which has a resistivity in the range of 50-80 Ω∙cm. The I-V curve obtained in dark condition evidences the structure a rectifying junction, which is further confirmed by placing external bias. Compared to the resistance state modulated by electric field only in dark (without illumination), the switching voltage driving the resistance state of the structure from one state to the other, shows clear shift under a spot laser illumination...
November 9, 2017: Scientific Reports
Stephen W Howell, Isaac Ruiz, Paul S Davids, Richard K Harrison, Sean W Smith, Michael D Goldflam, Jeffrey B Martin, Nicholas J Martinez, Thomas E Beechem
A sensitive optical detector is presented based on a deeply depleted graphene-insulator-semiconducting (D(2)GIS) junction, which offers the possibility of simultaneously leveraging the advantages of both charge integration and localized amplification. Direct read-out and built-in amplification are accomplished via photogating of a graphene field-effect transistor (GFET) by carriers generated within a deeply depleted low-doped silicon substrate. Analogous to a depleted metal-oxide-semiconducting junction, photo-generated charge collects in the potential well that forms at the semiconductor/insulator interface and induces charges of opposite polarity within the graphene film modifying its conductivity...
November 7, 2017: Scientific Reports
Qixing Wang, Jun Guo, Zijing Ding, Dianyu Qi, Jizhou Jiang, Zhuo Wang, Wei Chen, Yuanjiang Xiang, Wenjing Zhang, Andrew T S Wee
Monolayer two-dimensional (2D) transition metal dichalcogenides (TMDs) show interesting optical and electrical properties because of their direct bandgap. However, the low absorption of atomically thin TMDs limits their applications. Here, we report enhanced absorption and optoelectronic properties of monolayer molybdenum disulfide (MoS2) by using an asymmetric Fabry-Perot cavity. The cavity is based on a hybrid structure of MoS2/ hexagonal boron nitride (BN)/Au/SiO2 realized through layer-by-layer vertical stacking...
November 14, 2017: Nano Letters
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