Controlled optical transition rates in nanodroplets

The time-resolved fluorescence measurements of 3,3′-diethyl-5,5′-dichloro-9-phenylthiacarbocyanine (DDPT) in bulk solvents and methanol-in-oil reverse micellar systems is presented which include nano-sized methanol droplets stabilized with anionic surfactant aerosol-OT (AOT) in n-heptane, at room temperature. Relative fluorescence intensities of DDPT increase with a factor of 16 in m/o reverse micelles in comparison to those in bulk methanol. The radiative and nonradiative rate constants decreases in methanol dispersions, indicating that internal motions of DDPT in the droplets is reduced due to strong electrostatic interactions between the positively charged DDPT and the negatively charged sulfonate head-groups of AOT

Factors affecting the outcome of surgically treated non-iatrogenic traumatic cervical esophageal perforation: 28 years experience at a single center

<p>Abstract</p> <p>Background</p> <p>We reviewed our experience with non-iatrogenic traumatic cervical esophageal perforations, paying particular attention to factors affecting the outcome of such cases.</p> <p>Methods</p> <p>In total, 30 patients treated surgically between 1980 and 2008 for non-iatrogenic traumatic cervical esophageal perforation in our clinic were reviewed.</p> <p>Results</p> <p>There were 25 male and 5 female patients with a median age of 27.5 years. The type of injury was external trauma in 21 (70%) patients and endoluminal injury in the remaining 9 (30%) patients. The mechanism of injury was gunshot in 16 patients, stabbing in 4, falling in 1 (extraluminal injury), and foreign body in 9 (endoluminal injuries). The overall mortality rate was 16.6% (5/30). The mortality rate for extraluminal injuries was 19%, and for endoluminal injuries was 11.1%. Mortality in patients treated within 24 h of sustaining injury was substantially less than in those for whom diagnosis and treatment were delayed (12.5 and 21.4%, respectively). The mortality rate was 33.3% (3/9) for patients with tracheal injuries and 9.5% (2/21) for those without tracheal injuries.</p> <p>Conclusions</p> <p>A treatment delay greater than 24 h, the presence of tracheal injury, or extraluminal perforation significantly affected the outcome of surgically treated non iatrogenic traumatic cervical esophageal perforation.</p

Probing nanoscale domains of J-aggregates deposited on a mica surface

J-aggregates of 1, 1',3,3'-tetraethyl-5,5',6,6'-tetrachlorobenzimidazolocarbocyanine (TTBC) were deposited on a mica surface and probed by atomic force microscopy operated at tapping mode in air. Optical spectra showed that J-aggregates were formed in aqueous solutions. Atomic force microscopy images revealed that J-aggregates deposited on mica surfaces mainly present single domains with a mean height of 2.00 +/- 0.25 nm and an average diameter of 100 +/- 20 nm. Quantitative analysis of the morphology of images indicated that the single domain of J-aggregates exhibits very uniform height and diameter distributions with polydispersity indices of 1.02 and 1.04, respectively. Based on the results, we propose a two-dimensional nanostructure in which TTBC J-aggregates could be arranged in a monolayer

Controlled formation of the two-dimensional TTBC J-aggregates in an aqueous solution

Strong experimental and theoretical evidence was provided on the controlled formation of the two-dimensional J-aggregates that were assembled in the herringbone morphology. The exciton-band structure formation of 1,1',3,3'-tetraethyl-5,5',6,6'-tetrachlorobenzimidazolocarbocyanine (TTBC) J-aggregates was investigated in ionic ( NaOH) aqueous solution at room temperature. The control was achieved by changing the [TTBC] at a given [NaOH], or vice versa, and was monitored through the changes in the absorption, fluorescence excitation, and emission spectra. Specific attention was paid to expose the excited-state structure and dynamics through simulations of the excitonic properties, which included diagonal energetic disorder and phonon-assisted exciton relaxation. Aggregates were characterized by an asymmetrically split Davydov pair, an H-band (similar to 500 nm, 1300 cm(-1) wide, Lorentzian-like) and a J-band (similar to 590 nm, 235 cm(-1) wide, with a band shape typical of a one-dimensional J-aggregate), whose relative intensities showed a strong dependence on the [TTBC]/[NaOH]. The H-band is favored by high [TTBC] or high [NaOH]. An explanation of the control on the aggregate formation was given by correlating the changes in the absorption with the structural modifications and the subsequent changes in the dynamics, which were induced by variations in the dye and NaOH concentrations. The J-band shape/width was attributed to disorder and disorder-induced intraband phonon-assisted exciton relaxation. The intraband processes in both bands were estimated to occur in the same time scale (about a picosecond). It has been suggested that the wide energetic gap between the Davydov split bands (3000 cm(-1)) could get bridged by the excitonic states of the loosely coupled chains, in addition to the monomeric species at low [TTBC]. Phonon-assisted interband relaxation, through the band gap states and/or directly from the H- to the J-band, are suggested for accounting the difference between the bandwidths and shapes of the two bands. Energy transfer between the H- band and the monomeric species is suggested as crucial for tuning the relative strengths of the two bands

Synthesis and Photophysical Characterizations of Thermal -Stable Naphthalene Benzimidazoles

WOS: 000293188900032PubMed ID: 21279540Microwave-assisted synthesis, photophysical and electrochemical properties of thermal-stable naphthalene benzimidazoles and naphthalimides are studied in this paper. Microwave-assisted synthesis of naphthalene benzimidazoles provide higher yields than the conventional thermal synthesis. Comparative photophysical properties of naphthalene benzimidazoles and naphthalimides are revealed that conjugation of electron-donating group onto naphthalimide moiety increases fluorescence quantum yields. Fluorophore-solvent interactions are also investigated using Lippert-Mataga equation for naphthalimides and naphthalene benzimidazoles. Thermal stabilities of naphthalene benzimidazoles are better than naphthalimides due to increased aromaticity. The experimental E-LUMO levels of naphthalene benzimidazoles are found to be between 3.15 and 3.28 eV. Therefore, naphthalene benzimidazole derivatives consisting of anchoring groups are promising materials in organic dye sensitized solar cells.Scientific and Technological Research Council of Turkey, TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TBAG_106T061]; Alexander von Humboldt Foundation of GermanyAlexander von Humboldt Foundation; European Science Foundation (ESF)European Science Foundation (ESF)We acknowledge financial support from Scientific and Technological Research Council of Turkey, TUBITAK, TBAG_106T061 and the Alexander von Humboldt Foundation of Germany and European Science Foundation (ESF) for research supports. I thank Mechanical Engineer DI. Cagatay Ela for proof-reading

Efficiency in Centralized DC Systems Compared with Distributed DC Systems in Photovoltaic Energy Conversion

Photovoltaic (PV) systems produce a significant amount of electrical energy used around the world. The performance of a PV array is affected by temperature, solar insolation, shading and array configuration. Obtainable maximum power generation from PV based energy production systems is only possible with Maximum Power Point Tracking (MPPT) methods. In order to maximize the efficiency of PV energy conversion systems, solar panels and arrays should be operated at maximum power points. At maximum power point, solar arrays generate the electric energy at maximum efficiency and minimum losses. This paper discusses the following issues: (1) what is the effect of MPPT unit in PV systems, (2) two connection methods between solar arrays and buck-boost DC/DC converter with MPPT unit, (3) determine behaviours of PV power generation systems in cloudy and sunny conditions

Engineered silica nanoparticles are biologically safe vehicles to deliver drugs or genes to liver cells

Tuncel, Ozge/0000-0002-0873-133X; Atabey, Nese/0000-0003-4966-2980; BAGCI, GULSUN/0000-0002-3901-6275WOS:000600872000003PubMed: 33321631Engineered silica nanoparticles (SiNP) are emerging materials for medical applications. Evaluating biological responses of specific cells treated with engineered silica nanoparticles is however essential. We synthesized and characterized the physicochemical properties of silica nanoparticles with two different sizes of 10 and 100 nm (10SiNP and 100SiNP) dispersed in cell culture medium. HuH-7, an epithelial-like human hepatoblastoma cell line and SK-HEP-1, a liver sinusoidal endothelial cell line (LSEC) are employed to evaluate their biological responses for the SiNP treatment. Primary human lymphocytes are used to assess genotoxicity recommended by OECD guidelines while erythrocytes are used to assess hemolytic activity. The engineered silica nanoparticles are not able to produce radical species, to alter the mitochondrial membrane potential, and induce any adverse effects on cell proliferation. The colony formation ability of HuH-7 hepatoblastoma cells was not affected following the SiNP treatment. Furthermore, SiNPs do not induce hemolysis of red blood cells and are not genotoxic. These findings suggest that SiNPs regardless of the size, amount, and incubation time are biologically safe vehicles to deliver drugs or genes to the liver.Izmir Institute of TechnologyIzmir Institute of Technology [2012IYTEBAP06]This work was supported by the Izmir Institute of Technology [grant number 2012IYTEBAP06]

Human papillomavirus frequency of women at-low risk of developing cervical cancer: a preliminary study from a Turkish university hospital

Purpose: To investigate the frequency of human papillomavirus (HPV) infection among low-risk women for cervical cancer in our region

Evaluation of Patients Undergoing Removal of Glass Fragments From Injured Hands A Retrospective Study

WOS: 000292505600006PubMed ID: 21372675The hand is the body part most frequently injured by broken glass. Glass fragments lodged in soft tissues may result in numerous complications, such as infection, delayed healing, persistent pain, and late injury as a result of migration. Between 2005 and 2010, we removed 46 glass particles from the hands of 26 patients. The injuries were caused by the following: car windows broken during motor vehicle accidents in 11 patients (42%); fragments from broken glasses, dishes, or bottles in 9 (35%); the hand passing through glass in 5 (19%); and a fragment from a broken fluorescent lamp in 1 (4%) patient. Despite the efficacy of plain radiographs in detecting glass fragments, these are sometimes not obtained. Given the relatively low cost, accessibility, and efficacy of radiographs, and the adverse consequences of retained foreign bodies, the objections to obtaining radiographs should be few in diagnosing glass-related injuries of the hand