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Berthold Seitz, Achim Langenbucher, Tobias Hager, Edgar Janunts, Moatasem El-Husseiny, Nora Szentmáry
BACKGROUND: In case of keratoconus, rigid gas-permeable contact lenses as the correction method of first choice allow for a good visual acuity for quite some time. In a severe stage of the disease with major cone-shaped protrusion of the cornea, even specially designed keratoconus contact lenses are no more tolerated. In case of existing contraindications for intrastromal ring segments, corneal transplantation typically has a very good prognosis. METHODS: In case of advanced keratoconus - especially after corneal hydrops due to rupture of Descemet's membrane - penetrating keratoplasty (PKP) still is the surgical method of first choice...
2017: Open Ophthalmology Journal
A D Cabral, B I Murcar-Evans, K Toutah, M Bancerz, D Rosa, K Yuen, T B Radu, M Ali, A Penkul, D Kraskouskaya, P T Gunning
Chemosensors for the detection of phosphate-containing biological species are in high need. Detection of proximally phosphorylated sites of PPi and those found in peptides and proteins has been demonstrated using chemosensors containing pyrene, as a fluorescent reporter, and a Zn(2+)-chelate, as a phosphate-binding group. Using these sensors, detection of proximal phosphate groups is afforded by binding of at least two of the sensor molecules to the adjacent phosphates, via the Zn(2+) centres, leading to excimer formation between the pyrene groups and the corresponding shift in emission from 376 to 476 nm...
September 20, 2017: Analyst
Mohammad Ghoreishi, Mohammad-Ali Abtahi, Iman Seyedzadeh, Hamid Fesharaki, Mohadeseh Mohammadnia, Hamidreza Jahanbani-Ardakani, Seyed-Hossein Abtahi
BACKGROUND: The aim of this study is to evaluate the results of photorefractive keratectomy (PRK) in the management of postoperative hyperopia and astigmatism in patients with history of radial keratotomy (RK). MATERIALS AND METHODS: This prospective nonrandomized noncomparative interventional case series enrolled consecutive eyes treated with PRK after RK. In cases, in which (1) wavefront (WF) scan was undetectable during primary examinations; and/or, (2) WF data were not transferable to the excimer laser device, patients were treated with the tissue-saving (TS) mode...
2017: Journal of Research in Medical Sciences: the Official Journal of Isfahan University of Medical Sciences
Ayako Okada, Morio Shoda, Hiroaki Tabata, Wataru Shoin, Hideki Kobayashi, Takahiro Okano, Koji Yoshie, Yasutaka Oguchi, Takahiro Takeuchi, Ken Kato, Koichiro Kuwahara
BACKGROUND: The estimated incidence of infected cardiac implantable electric devices (CIED) has recently increased to 1-2% in Japan. Extraction of long-term implanted devices is generally difficult. There are few reports about lead extraction in Japan. We describe our experience with and outcomes of lead extraction using excimer lasers, mechanical sheaths, and manual extraction. METHODS: We retrospectively analyzed the characteristics, types of devices, and indications for extraction in 29 patients with 67 leads who required CIED lead extraction at Shinshu University Hospital between April 2014 and October 2016...
September 13, 2017: Journal of Cardiology
Qi Wan, Dan Wang, HongQuan Ye, Jing Tang, Yu Han
PURPOSE: The aim of this study was to review the safety and stability of cornea cross-linking (CXL) for the treatment of keratectasia after Excimer Laser Refractive Surgery. METHODS: Eligible studies were identified by systematically searching PubMed, Embase, Web of Science and reference lists. Meta-analysis was performed using Stata 12.1 software. The primary outcome parameters included the changes of corrected distant visual acuity (CDVA), uncorrected visual acuity (UCVA), the maximum keratometry value (Kmax) and minimum keratometry value (Kmin), the surface regularity index (SRI), the surface asymmetry index (SAI), the keratoconus prediction index (KPI), corneal thickness, and endothelial cell count...
September 2017: Journal of Current Ophthalmology
Fei Ma, Wen-Jing Liu, Qianyi Zhang, Chun-Yang Zhang
Herein, we develop a simple fluorescence method for the sensitive detection of microRNAs based on duplex specific nuclease-assisted target recycling and pyrene excimer switching. This method is extremely sensitive with a detection limit of 0.58 fM, and it can be applied to absolutely detect endogenous microRNAs in cancer cells, holding great potential for clinical diagnosis and biomedical research studies.
September 21, 2017: Chemical Communications: Chem Comm
Justin C Johnson, Josef Michl
In this review we first provide an introductory description of the singlet fission phenomenon and then describe the ground and electronically excited states of the parent 1,3-diphenylisobenzofuran chromophore (1) and about a dozen of its derivatives. A discussion of singlet fission in thin polycrystalline layers of these materials follows. The highest quantum yield of triplet formation by singlet fission, 200% at 80 K, is found in one of the two known crystal modification of the parent. In the other modification and in many derivatives, excimer formation competes successfully and triplet yields are low...
September 11, 2017: Topics in Current Chemistry (Journal)
Sureshbabu Nagarajan, Lisa Jill Lapidus
The aggregation of intrinsically disordered and misfolded proteins in the form of oligomers and fibrils plays a crucial role in a number of neuro and non-neurodegenerative diseases. Currently, most probes and biophysical techniques that detect and characterize fibrils to high resolution fail to show sensitivity and binding for oligomers. Here we show 9-(dicyano-vinyl) julolidine (DCVJ), a class of molecular rotor, binds Aβ early aggregates and reports on the kinetics as well as packing of oligomer formation...
September 11, 2017: Chembiochem: a European Journal of Chemical Biology
Taj M Khan, Mubarak M Mujawar, Katarzyna E Siewerska, Anuj Pokle, Tony Donnelly, Niall McEvoy, Georg S Duesberg, James G Lunney
A new method for pulsed laser deposition of plasmonic silver nanoparticle films in flowing gas at atmospheric pressure is described. The ablation was done using an excimer laser at 248 nm. Fast optical imaging shows that the ablation plume is captured by the flowing gas, and is expected to form a nanoparticle aerosol, which is carried 5 - 20 mm to the substrate. The dependence of the deposition rate on laser fluence, gas flow velocity, and target-substrate distance was investigated using electron microscopy and absorption spectroscopy of the deposited films...
September 8, 2017: Nanotechnology
Yilei Wu, Jiawang Zhou, Brian T Phelan, Catherine M Mauck, J Fraser Stoddart, Ryan M Young, Michael R Wasielewski
Facile exciton transport within ordered assemblies of π-stacked chromophores is essential for developing molecular photonic and electronic materials. Excimer states having variable charge transfer (CT) character are frequently implicated as promoting or inhibiting exciton mobility in such systems. However, determining the degree of CT character in excimers as a function of their structure has proven challenging. Herein, we report on a series of cyclophanes in which the interplanar distance between two phenyl-extended viologen (<b>ExV<sup>2+</b>) </sup>chromophores is varied systematically using a pair of o-, m-, or p-xylylene (<b>o-</b>, <b>m-</b>, or <b>p-Xy</b>) covalent linkers to produce <b>o-ExBox<sup>4+</sup></b> (3...
September 7, 2017: Journal of the American Chemical Society
Joscha Hoche, Hans-Christian Schmitt, Alexander Humeniuk, Ingo Fischer, Roland Mitrić, Merle I S Röhr
The understanding of excimer formation in organic materials is of fundamental importance, since excimers profoundly influence their functional performance in applications such as light-harvesting, photovoltaics or organic electronics. We present a joint experimental and theoretical study of the ultrafast dynamics of excimer formation in the pyrene dimer in a supersonic jet, which is the archetype of an excimer forming system. We perform simulations of the nonadiabatic photodynamics in the frame of TDDFT that reveal two distinct excimer formation pathways in the gas-phase dimer...
September 20, 2017: Physical Chemistry Chemical Physics: PCCP
Tae-Il Kim, Hanyong Jin, Jeehyeon Bae, Youngmi Kim
A fluorescent probe based on an excimer-forming benzothiazolyl-cyanovinylene (CV) dye was developed to target the apoptotic protease caspase-3. Upon the action of caspase-3, the water-soluble fluorescent probe Ac-DEVD-NH-CV, which is weakly green emissive in aqueous solution, is converted to hydrophobic CV-NH2, which spontaneously aggregates. Aggregation of CV-NH2 promotes excimer emission of the CV dye, which allows for the study of caspase-3 activity in vitro and for imaging the activity of the enzyme in living cells because of the large red shift and enhanced fluorescence signal of the probe...
September 12, 2017: Analytical Chemistry
Eric R Kennehan, Christopher Grieco, Alyssa N Brigeman, Grayson S Doucette, Adam Rimshaw, Kayla Bisgaier, Noel C Giebink, John B Asbury
Ultrafast vibrational spectroscopy in the mid-infrared was used to directly probe the delocalization of excitons in two different perylenediimide (PDI) derivatives that are predicted to preclude the formation of excimers, which can act as trap sites for excited state energy in organic semiconductors. We identified vibrational modes within the conjugated C-C stretch modes of PDI molecules whose frequencies reported the interactions of molecules within delocalized excitonic states. The vibrational linewidths of these modes, which we call intermolecular coordinate coupled (ICC) modes, provided a direct probe of the extent of exciton delocalization among the PDI molecules, which was confirmed using X-ray diffraction and electro-absorption spectroscopy...
September 20, 2017: Physical Chemistry Chemical Physics: PCCP
Mark D Mifflin, Xavier M Mortensen, Brent S Betts, Cole Gross, Brian Zaugg
PURPOSE: To study the accuracy and reliability of optical pachymetry using the Alcon WaveLight EX500 during laser-assisted in situ keratomileusis (LASIK). MATERIALS AND METHODS: This was a retrospective chart review of 90 eyes from 45 patients who had undergone LASIK (mean age 35.2±8.2 years; 19 males, 26 females). The WaveLight FS200 femtosecond laser was programmed to cut LASIK flaps at a desired depth of 120 μm. Optical low-coherence reflectometry (WaveLight EX500) was used to measure central corneal thickness prior to lifting the flap, and the residual stromal bed immediately after excimer ablation...
2017: Clinical Ophthalmology
Kavita Goyal, Michael O Nguyen, Rachel V Reynolds, Arash Mostaghimi, Cara Joyce, Jeffrey M Cohen, Elizabeth A Buzney
BACKGROUND/PURPOSE: Phototherapy utilization has declined over the last 20 years despite its efficacy and cost-effectiveness. Adequacy of phototherapy training in residency may be a contributing factor. The purpose of this study was to evaluate perceptions of U.S. dermatology residency program directors (PDs) regarding the effectiveness of their programs' phototherapy training and what constitutes adequate phototherapy education. METHODS: A questionnaire was sent to PDs to assess phototherapy training within their program; aspects such as dedicated time, exposure to different modalities, and barriers to resident education were surveyed...
August 30, 2017: Photodermatology, Photoimmunology & Photomedicine
Ilya Aparin, Gleb V Proskurin, Andrey V Golovin, Alexey V Ustinov, Andrey A Formanovsky, Timofei S Zatsepin, Vladimir A Korshun
Oligonucleotide probes labeled with pyrene pairs that form excimers have a number of applications in hybridization analysis of nucleic acids. A long excited state lifetime, large Stokes shift and chemical stability make pyrene excimer an attractive fluorescent label. Here we report synthesis of a chiral phosphoramidite building blocks based on (R)-4-amino-2,2-dimethylbutane-1,3-diol, easily available from an inexpensive D-(-)-pantolactone. 1-Pyreneacetamide, 1-pyrenecarboxamide and Dabcyl derivatives have been used in preparation of molecular beacon (MB) probes labeled with one or two pyrenes/quenchers...
August 31, 2017: Journal of Organic Chemistry
Franz Trautinger
Mycosis fungoides (MF), the most common variant of among cutaneous T cell lymphomas (CTCL), is characterised in its early stages by clonal proliferation of malignant T-cells in the skin manifesting as erythematous patches and plaques with a chronic course and progression to cutaneous tumors and extracutaneous organs in some patients. Skin directed therapies (SDT) are primarily used for effective palliation in early stage disease. Phototherapy with ultraviolet A radiation combined with 8-methoxypsoralen (PUVA) and with ultraviolet B radiation (UVB) has a longstanding history in the treatment of MF and are highly effective in inducing remissions...
July 28, 2017: Giornale Italiano di Dermatologia e Venereologia: Organo Ufficiale, Società Italiana di Dermatologia e Sifilografia
Takayo Moriuchi-Kawakami, Youji Hisada, Akihisa Higashikado, Tsubasa Inoue, Keiichi Fujimori, Toshiyuki Moriuchi
A new malonate possessing two pyrene moieties was synthesized as a fluoroionophore, and its structure and fluorescence spectroscopic properties were investigated. When excited at 344 nm in acetonitrile/chloroform (9:1, v/v), the synthesized bispyrenyl malonate has the fluorescence of intramolecular excimer (λem = 467 nm) emissions and not a pyrene monomer emission (λem = 394 nm). A large absolute fluorescence quantum yield was obtained in the solid state (ΦPL = 0.65) rather than in solution (ΦPL = 0.13)...
August 25, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Ariadne Prigipaki, Katerina Papanikolopoulou, Estelle Mossou, Edward P Mitchell, V Trevor Forsyth, Alexandros Selimis, Anthi Ranella, Anna Mitraki
In this study, we propose a photostructuring approach for protein films based on a treatment with nanosecond pulses of a KrF excimer laser. As a model protein we used an amyloid fibril-forming protein. Laser treatment induced a foaming of the sample surface exhibiting an interconnected fibrous mesh with a high degree of control and precision. The surface foaming was well characterized by scanning electron microscopy, atomic force microscopy, laser induced fluorescence and contact angle measurements. The laser irradiated areas of the protein films acquired new morphological and physicochemical properties that could be exploited to fulfill unmet challenges in the tissue engineering field...
September 7, 2017: Biofabrication
Wei-Bing Liu, Li-Wei Sun, Hua Yang, Yan-Fei Wang
Oral lichen planus (OLP) is a chronic inflammatory disease, has prolonged courses, repeated attacks and resistance to treatment. The traditional narrow spectrum UVB treatment has an established efficacy on skin lichen planus, and high safety. However, most of ultraviolet phototherapy devices have a huge volume, thereby cannot be used in the treatment of OLP. Lymphocytic infiltration is evident in the lesions of lichen planus, and the direct irradiation of 308-nm excimer laser can induce apoptosis of the T lymphocytes in skin lesions, thereby has a unique therapeutic effect on the diseases involving T lymphocytes...
August 23, 2017: Dermatologic Therapy
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