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Sample records for photoinduced wolff rearrangement

  1. Photo-Wolff Rearrangement of 2-Diazo-1,2-naphthoquinone: Stern-Volmer Analysis of the Stepwise Reaction Pathway.

    PubMed

    Ladinig, Manfred; Ramseier, Markus; Wirz, Jakob

    2015-01-01

    2-Diazo-1,2-naphthoquinone (1) and its derivatives are the photoactive components in Novolak photoresists. A femtosecond infrared study has established that the photoreaction of 1 proceeds largely by a concerted Wolff rearrangement yielding the ketene 1H-inden-1-ylidene-methanone (3) within 300 fs after excitation, but earlier trapping studies gave evidence for a minor reaction path via a carbene intermediate 1-oxo-2(1H)-naphthalenylidene (2) with a lifetime of about 10 ps. Here, we provide a quantitative assessment of the stepwise pathway by Stern-Volmer analysis of the trapping of 2 by methanol to yield 2-methoxy-1-naphthol (4). We conclude that the lifetime of the carbene 2 is at least 200 ps. Moreover, [3 + 2]cycloaddition of 2 and acetonitrile yielding 2-methylnaphth[2,1-d]oxazole (5) was observed. A comparison of the yields of 5 formed upon photolysis and upon thermolysis of 1 in acetonitrile provides evidence that a substantial part of the hot nascent carbene 2 formed photolytically rearranges to the ketene 3 during its vibrational relaxation (hot ground-state reaction). PMID:25196741

  2. Reaction Mechanisms of a Photo-Induced [1,3] Sigmatropic Rearrangement via a Nonadiabatic Pathway

    NASA Astrophysics Data System (ADS)

    Wu, Weiqiang; Liu, Kunhui; Yang, Chunfan; Zhao, Hongmei; Wang, Huan; Yu, Youqing; Su, Hongmei

    2009-11-01

    Time-resolved Fourier transform infrared absorption spectroscopy measurements and B3LYP/cc-pVDZ calculations have been conducted to characterize the reaction dynamics of a remarkable photoinduced 1,3-Cl sigmatropic rearrangement reaction upon 193 or 266 nm excitation of the model systems acryloyl chloride (CH2CHCOCl) and crotonyl chloride (CH3CHCHCOCl) in solution. The reaction is elucidated to follow nonadiabatic pathways via two rapid ISC processes, S1 → T1 and T1 → S0, and the S1/T1 and T1/S0 surface intersections are found to play significant roles leading to the nonadiabatic pathways. The S1 → T1 → S0 reaction pathway involving the key participation of the T1 state is the most favorable, corresponding to the lowest energy path. It is also suggested that the photoinduced 1,3-Cl migration reaction of RCHCHCOCl (R = H, CH3) proceeds through a stepwise mechanism involving radical dissociation-recombination, which is quite different from the generally assumed one-step concerted process for pericyclic reactions.

  3. Wolff-Parkinson-White syndrome

    MedlinePlus

    Wolff-Parkinson-White syndrome is a condition in which there is an extra electrical pathway of the heart. The ... to periods of rapid heart rate ( tachycardia ). Wolff-Parkinson-White syndrome is one of the most common ...

  4. Genetics Home Reference: Wolff-Parkinson-White syndrome

    MedlinePlus

    ... Home Health Conditions Wolff-Parkinson-White syndrome Wolff-Parkinson-White syndrome Enable Javascript to view the expand/ ... Download PDF Open All Close All Description Wolff-Parkinson-White syndrome is a condition characterized by abnormal ...

  5. Wolff-Parkinson-White syndrome.

    PubMed

    Morscher, J H

    1992-02-01

    Wolff-Parkinson-White (WPW) syndrome is a cardiac conduction disorder that presents with potentially life-threatening consequences. Wolff-Parkinson-White syndrome-induced dysrhythmias account for 20% of all supraventricular tachycardias that occur in the general population. Clinical presentations range from no symptoms to a sudden cardiac arrest. The risk of sudden death is always present with WPW syndrome, and it is the motivating force in the evaluation and treatment of this syndrome. Current diagnostic modalities are accurate in identifying patients with WPW syndrome, but lack the sensitivity to predict sudden cardiac death. This article reviews the history of WPW syndrome, as well as its general characteristics, diagnostic criteria, treatment modalities, and nursing implications. PMID:1554559

  6. REMARKS ON THE MAX WOLFF REPORT.

    ERIC Educational Resources Information Center

    GORDON, EDMUND W.

    STRENGTHS AND WEAKNESSES OF THE WOLFE REPORT (SIX MONTHS LATER. STUDY I. PS 000 281) ARE NOTED. WEAKNESSES ARE JUDGED TO BE THAT WOLFF DID NOT CONTROL VARIATIONS IN TEACHER EFFECTIVENESS, CURRICULUM, OR STUDENT CHARACTERISTICS. STRENGTHS ARE (1) PARENT INTERVIEWS, (2) ASSESSMENT OF HEAD START-KINDERGARTEN TRANSITION, (3) RECOGNITION OF THREE…

  7. Photoinduced hydrogen-bonding dynamics.

    PubMed

    Chu, Tian-Shu; Xu, Jinmei

    2016-09-01

    Hydrogen bonding dynamics has received extensive research attention in recent years due to the significant advances in femtolaser spectroscopy experiments and quantum chemistry calculations. Usually, photoexcitation would cause changes in the hydrogen bonding formed through the interaction between hydrogen donor and acceptor molecules on their ground electronic states, and such transient strengthening or weakening of hydrogen bonding could be crucial for the photophysical transformations and the subsequent photochemical reactions that occurred on a time scale from tens of femtosecond to a few nanoseconds. In this article, we review the combined experimental and theoretical studies focusing on the ultrafast electronic and vibrational hydrogen bonding dynamics. Through these studies, new mechanisms and proposals and common rules have been put forward to advance our understanding of the hydrogen bondings dynamics in a variety of important photoinduced phenomena like photosynthesis, dual fluorescence emission, rotational reorientation, excited-state proton transfer and charge transfer processes, chemosensor fluorescence sensing, rearrangements of the hydrogen-bond network including forming and breaking hydrogen bond in water. Graphical Abstract We review the recent advances on exploring the photoinduced hydrogen bonding dynamics in solutions through a joint approach of laser spectroscopy and theoretical calculation. The reviewed studies have put forward a new mechanism, new proposal, and new rule for a variety of photoinduced phenomena such as photosynthesis, dual fluorescence emission, rotational reorientation, excited-state proton transfer and charge transfer, chemosensor fluorescence sensing, and rearrangements of the hydrogen-bond network in water. PMID:27491849

  8. Redesigning Regional Accreditation: An Interview with Ralph A. Wolff

    ERIC Educational Resources Information Center

    Smith, Virginia B.; Finney, Joni E.

    2008-01-01

    This article presents an interview with Ralph Wolff, the president and executive director of the Western Association of Schools and Colleges since 1996 and the 2008 recipient of the Virginia B. Smith (VBS) Innovative Leadership Award for his work in the redesign of regional accreditation. In this interview, Wolff discusses the creation of a new…

  9. Generalized model for photoinduced surface structure in amorphous thin films.

    PubMed

    Lu, Chao; Recht, Daniel; Arnold, Craig

    2013-09-01

    We present a generalized model to explain the spatial and temporal evolution of photoinduced surface structure in photosensitive amorphous thin films. The model describes these films as an incompressible viscous fluid driven by a photoinduced pressure originating from dipole rearrangement. This derivation requires only the polarizability, viscosity and surface tension of the system. Using values of these physical parameters, we check the validity of the model by fitting to experimental data of As2S3 and demonstrating good agreement. PMID:25166680

  10. [Overlooked Wolff-Parkinson-White syndrome].

    PubMed

    Nielsen, Trine Skov; Dalager, Søren; Larsen, Maiken Kudahl; Jensen, Henrik Kjaerulf; Lundemose, Jytte Banner

    2010-09-13

    An autopsy in a 28-year-old man did not explain the cause of sudden unexpected death. However, a history of episodes with tachycardia and dizziness and a reassessed previous electrocardiogram exhibiting ventricular pre-excitation was consistent with Wolff-Parkinson-White (WPW) syndrome. In this patient we believe that the occurrence of atrial fibrillation caused sudden cardiac death from ventricular fibrillation due to a short refractory period of an accessory atrioventricular pathway and a very rapid ventricular rate in atrial fibrillation. PMID:20836960

  11. Biographical sketch: Julius Wolff, 1836-1902.

    PubMed

    Brand, Richard A

    2010-04-01

    This biographical sketch on Julius Wolff corresponds to a translation of the historic text, Zur Lehre von der Fracturenheilung, available at DOI 10.1007/s11999-010-1240-9 ; and a translation and abridgement of the historic text, Ueber die Innere Architectur der Knochen und ihre Bedeutung für die Frage vom Knochenwachstum, available at DOI 10.1007/s11999-010-1239-2 . (Supplemental materials are available with the online version of CORR.) An accompanying Editorial is available at DOI 10.1007/s11999-010-1238-3 . PMID:20151232

  12. Microwave Assisted Wolff-Kishner Reduction Reaction

    NASA Astrophysics Data System (ADS)

    Parquet, Eric; Lin, Qun

    1997-10-01

    A Wolff-Kishner reduction of a carbonyl group was carried out in a household microwave oven. Isatin was first converted to the hydrazone with 55% hydrazine and ethylene glycol by irradiation in the microwave oven at medium power for 30 seconds. Then, isatin 3-hydrazone was mixed with ethylene glycol and potassium hydroxide and irradiated in the microwave oven for only 10 seconds. After simple work-up and recrystallization, oxindole was obtained in a yield of 32.4%. The two step syntheses described here offer several advantages: (1) very short reaction time with no need for special microscale glassware, (2) mild experimental conditions (hot oil baths and heating mantles are not required), (3) the reagents are easy to handle (students do not need to prepare sodium ethoxide from sodium metal and absolute ethanol).

  13. History of Wolff-Parkinson-White syndrome.

    PubMed

    Scheinman, Melvin M

    2005-02-01

    While Drs. Wolff, Parkinson, and White fully described the syndrome that bears their names in 1930, prior case reports had already described the essentials. Over the ensuing century this syndrome has captivated the interest of anatomists, clinical cardiologists, and cardiac surgeons. Stanley Kent described lateral muscular connections over the atrioventricular (AV) groove, which he felt were the normal AV connections. The normal AV connections were, however, clearly described by His and Tawara. True right-sided AV connections were initially described by Wood et al., while Ohnell first described left free wall pathways. David Scherf is thought to be the first to describe our current understanding of the pathogenesis of the Wolff-Parkinson-White (WPW) syndrome in terms of a reentrant circuit involving both the AV node--His axis as well as the accessory pathway. This hypothesis was not universally accepted and many theories were applied to explain the clinical findings. The basics of our understandings were established by the brilliant work of Pick, Langendorf, and Katz who by using careful deductive analysis of ECGs were able to define the basic pathophysiological processes. Subsequently, Wellens and Durrer applied invasive electrical stimulation to the heart in order to confirm the pathophysiological processes. Sealy and his colleagues at Duke University Medical Center were the first to successfully surgically divide an accessory pathway and ushered in the modern area for curative therapy for these patients. Morady and Scheinman were the first to successfully ablate an accessory pathway (posteroseptal) using high-energy direct-current shocks. Subsequently, Jackman, Kuck, Morady, and a number of groups proved the remarkable safety and efficiency of catheter ablation for pathways in all locations using radiofrequency energy. More recently, Gallob et al. first described the gene responsible for a familial form of WPW. The current ability to cure patients with WPW is

  14. On the mechanism of photoinduced refractive index changes in phosphosilicate glass

    SciTech Connect

    Larionov, Yu V; Sokolov, V O; Plotnichenko, V G

    2010-05-26

    The photoinduced growth of the refractive index of phosphosilicate glass during Bragg grating inscription and the thermal decay of the grating have a number of unusual features. The observed index variations are interpreted in terms of a new model for photoinduced glass network rearrangement. The model assumes the formation of photoinduced voids (nanopores) in the glass network near point defects. The nanopores may migrate through the network via bond switching when the network is in a 'soft' state. The photoinduced variations in network density lead to index variations. (fibres)

  15. Wolff-Parkinson-white syndrome mimics a conduction disease.

    PubMed

    Marrakchi, S; Kammoun, I; Kachboura, S

    2014-01-01

    Background. It is important to recognise Wolff-Parkinson-White (WPW) syndrome in electrocardiograms (ECG), as it may mimic ischaemic heart disease, ventricular hypertrophy, and bundle branch block. Recognising WPW syndrome allows for risk stratification, the identification of associated conditions, and the institution of appropriate management. Objective. The present case showed that electrophysiological study is indicated in patients with abnormal ECG and syncope. Case Report. A 40-year-old man with Wolff-Parkinson-White syndrome was presented to emergency with syncope. A baseline ECG was a complete right branch block and posterior left hemiblock. He was admitted to the cardiac care unit for pacemaker implantation. The atypical figure of complete right branch block and posterior left hemiblock was thought to be a "false positive" of conduction abnormality. But the long anterograde refractory period of the both accessory pathway and atrioventricular conduction may cause difficulty in diagnosing Wolff-Parkinson-White syndrome, Conclusion. A Wolff-Parkinson-White Syndrome may mimic a conduction disease. No reliable algorithm exists for making an ECG diagnosis of a preexcitation syndrome with conduction disorders. This can lead to diagnostic and therapeutic dilemmas in the context of syncope. PMID:25114686

  16. Wolff-Parkinson-White Syndrome Mimics a Conduction Disease

    PubMed Central

    Marrakchi, S.; Kammoun, I.; Kachboura, S.

    2014-01-01

    Background. It is important to recognise Wolff-Parkinson-White (WPW) syndrome in electrocardiograms (ECG), as it may mimic ischaemic heart disease, ventricular hypertrophy, and bundle branch block. Recognising WPW syndrome allows for risk stratification, the identification of associated conditions, and the institution of appropriate management. Objective. The present case showed that electrophysiological study is indicated in patients with abnormal ECG and syncope. Case Report. A 40-year-old man with Wolff-Parkinson-White syndrome was presented to emergency with syncope. A baseline ECG was a complete right branch block and posterior left hemiblock. He was admitted to the cardiac care unit for pacemaker implantation. The atypical figure of complete right branch block and posterior left hemiblock was thought to be a “false positive” of conduction abnormality. But the long anterograde refractory period of the both accessory pathway and atrioventricular conduction may cause difficulty in diagnosing Wolff-Parkinson-White syndrome, Conclusion. A Wolff-Parkinson-White Syndrome may mimic a conduction disease. No reliable algorithm exists for making an ECG diagnosis of a preexcitation syndrome with conduction disorders. This can lead to diagnostic and therapeutic dilemmas in the context of syncope. PMID:25114686

  17. Caring for the Student with Wolff-Parkinson-White Syndrome

    ERIC Educational Resources Information Center

    Prenni, Patricia G.

    2009-01-01

    Wolff-Parkinson-White syndrome is a cardiac condition in which an extra electrical pathway within the heart causes an abnormal increase in heart rate. It affects one to three people of every 1,000 people worldwide, occurring more often in males. Diagnosis usually occurs during young adulthood, so it is important for school nurses to be familiar…

  18. Molecular rearrangements of superelectrophiles

    PubMed Central

    2011-01-01

    Summary Superelectrophiles are multiply charged cationic species (dications, trications, etc.) which are characterized by their reactions with weak nucleophiles. These reactive intermediates may also undergo a wide variety of rearrangement-type reactions. Superelectrophilic rearrangements are often driven by charge–charge repulsive effects, as these densely charged ions react so as to maximize the distances between charge centers. These rearrangements involve reaction steps similar to monocationic rearrangements, such as alkyl group shifts, Wagner–Meerwein shifts, hydride shifts, ring opening reactions, and other skeletal rearrangements. This review will describe these types of superelectrophilic reactions. PMID:21512598

  19. The patient with Wolff-Parkinson-White syndrome.

    PubMed

    Berry, V A

    1994-03-01

    Wolff-Parkinson-White (WPW) syndrome is characterized by a classic ECG pattern and a history of palpitations, syncope, pre-syncope, or tachyarrhythmias. An electrophysiology study is an integral part of the diagnosis and treatment of this disease, and with the advent of catheter ablative techniques, WPW syndrome is now considered a curable disease. The critical care nurse needs to be aware of the acute and chronic treatment of this syndrome, the complications of therapy, and the educational needs of the patient and family. PMID:8192882

  20. Asymptomatic Wolff-Parkinson-White Syndrome Should be Ablated.

    PubMed

    Pappone, Carlo; Santinelli, Vincenzo

    2012-09-01

    Wolff-Parkinson-White syndrome (WPW) is associated with a small but lifetime risk of cardiac arrest and/or sudden cardiac death (SCD). However, the exact risk is not well defined, particularly in asymptomatic persons. Over recent years the authors have collected and reported new follow-up data among a large number of asymptomatic WPW patients, particularly children, intensively followed. These data have significantly contributed to the knowledge and definition of the natural history of WPW from childhood to adulthood. The risk of SCD is higher in asymptomatic children than in adults, and early ablation can be offered only to selected subjects after electrophysiologic testing. PMID:26939947

  1. Photoinduced diffusion molecular transport

    NASA Astrophysics Data System (ADS)

    Rozenbaum, Viktor M.; Dekhtyar, Marina L.; Lin, Sheng Hsien; Trakhtenberg, Leonid I.

    2016-08-01

    We consider a Brownian photomotor, namely, the directed motion of a nanoparticle in an asymmetric periodic potential under the action of periodic rectangular resonant laser pulses which cause charge redistribution in the particle. Based on the kinetics for the photoinduced electron redistribution between two or three energy levels of the particle, the time dependence of its potential energy is derived and the average directed velocity is calculated in the high-temperature approximation (when the spatial amplitude of potential energy fluctuations is small relative to the thermal energy). The thus developed theory of photoinduced molecular transport appears applicable not only to conventional dichotomous Brownian motors (with only two possible potential profiles) but also to a much wider variety of molecular nanomachines. The distinction between the realistic time dependence of the potential energy and that for a dichotomous process (a step function) is represented in terms of relaxation times (they can differ on the time intervals of the dichotomous process). As shown, a Brownian photomotor has the maximum average directed velocity at (i) large laser pulse intensities (resulting in short relaxation times on laser-on intervals) and (ii) excited state lifetimes long enough to permit efficient photoexcitation but still much shorter than laser-off intervals. A Brownian photomotor with optimized parameters is exemplified by a cylindrically shaped semiconductor nanocluster which moves directly along a polar substrate due to periodically photoinduced dipole moment (caused by the repetitive excited electron transitions to a non-resonant level of the nanocylinder surface impurity).

  2. The functional integral formulation of the Schrieffer–Wolff transformation

    NASA Astrophysics Data System (ADS)

    Zamani, Farzaneh; Ribeiro, Pedro; Kirchner, Stefan

    2016-06-01

    We revisit the Schrieffer–Wolff transformation and present a path integral version of this important canonical transformation. The equivalence between the low-energy sector of the Anderson model in the so-called local moment regime and the spin-isotropic Kondo model is usually established via a canonical transformation performed on the Hamiltonian, followed by a projection. Here we present a path integral formulation of the Schrieffer–Wolff transformation which relates the functional integral form of the partition function of the Anderson model to that of its effective low-energy model. The resulting functional integral assumes the form of a spin path integral and includes a geometric phase factor, i.e. a Berry phase. Our approach stresses the underlying symmetries of the model and allows for a straightforward generalization of the transformation to more involved models. It thus not only sheds new light on a classic problem, it also offers a systematic route of obtaining effective low-energy models and higher order corrections. This is demonstrated by obtaining the effective low-energy model of a quantum dot attached to two ferromagnetic leads.

  3. Degradations and Rearrangement Reactions

    NASA Astrophysics Data System (ADS)

    Zhang, Jianbo

    This section deals with recent reports concerning degradation and rearrangement reactions of free sugars as well as some glycosides. The transformations are classified in chemical and enzymatic ways. In addition, the Maillard reaction will be discussed as an example of degradation and rearrangement transformation and its application in current research in the fields of chemistry and biology.

  4. [Sudden death in intermittent Wolff Parkinson White syndrome].

    PubMed

    Medeiros, A; Iturralde, P; Guevara, M; Mendoza, C; Colín, L

    2001-01-01

    Sudden death is a rare condition in asymptomatic patients with asymptomatic intermittent Wolff Parkinson syndrome (WPW); for this reason it is believed that these patients should not undergo to radiofrequency ablation. We report an asymptomatic 44 year old man who developed ventricular fibrillation with a pre-excited RR interval less than 200 msec during atrial fibrillation, as a first manifestation of WPW syndrome. The Holter monitoring showed intermittent pre-excitation at low heart rate (70 bpm). During the electrophysiological study a successfully radiofrequency catheter ablation of a right posteroseptal accessory pathway was performed. We concluded that intermittent pre-excitation may not be used to identify patients who are at risk of sudden death. Radiofrequency catheter ablation should be recommended in those patients with a very high success rate, and a low incidence of serious complications. PMID:11565363

  5. Evaluation and Management of Wolff-Parkinson-White in Athletes

    PubMed Central

    Rao, Ashwin L.; Salerno, Jack C.; Asif, Irfan M.; Drezner, Jonathan A.

    2014-01-01

    Context: Wolff-Parkinson-White (WPW) is a cardiac conduction system disorder characterized by abnormal accessory conduction pathways between the atria and the ventricles. Symptomatic patients classically present with palpitations, presyncope, or syncope that results from supraventricular tachycardia. While rare, sudden cardiac death may be the first manifestation of underlying disease and occurs more frequently in exercising individuals. Evidence Acquisition: Medline and PubMed databases were evaluated through 2012, with the following keywords: WPW, Wolff-Parkinson-White, pre-excitation, sudden cardiac death, risk stratification, and athletes. Selected articles identified through the primary search, along with relevant references from those articles, were reviewed for pertinent clinical information regarding the identification, evaluation, risk stratification, and management of WPW as they pertained to the care of athletes. Study Design: Systematic review. Level of Evidence: Level 1. Results: Diagnosis of WPW is confirmed by characteristic electrocardiogram changes, which include a delta wave, short PR interval, and widened QRS complex. Utilization of the electrocardiogram as part of the preparticipation physical evaluation may allow for early identification of asymptomatic individuals with a WPW pattern. Risk stratification techniques identify individuals at risk for malignant arrhythmias who may be candidates for curative therapy through transcatheter ablation. Conclusion: WPW accounts for at least 1% of sudden death in athletes and has a prevalence of at least 1 to 4.5 per 1000 children and adults. The risk of lethal arrhythmia appears to be higher in asymptomatic children than in adults, and sudden cardiac death is often the sentinel event. The athlete with WPW should be evaluated for symptoms and the presence of intermittent or persistent pre-excitation, which dictates further consultation, treatment, and monitoring strategies as well as return to play. PMID

  6. Photoinduced phase transitions.

    PubMed

    Bennemann, K H

    2011-02-23

    Optically induced ultrafast electronic excitations with sufficiently long lifetimes may cause strong effects on phase transitions like structural and nonmetal→metal ones and on supercooling, supersaturation, etc. Examples are the transitions diamond→graphite, graphite→graphene, non-metal→metal, solid→liquid and vapor→liquid, solid. Photoinduced formation of graphene and water condensation of saturated or supersaturated vapor due to increased bonding amongst water molecules are of particular interest. These nonequilibrium transitions are an ultrafast response, on a few hundred fs time scale, to the fast low to large energy electronic excitations. The energy of the photons is converted into electronic energy via electronic excitations changing the cohesive energy. This changes the chemical potential controlling the phase transition. In view of the advances in laser optics photon induced transitions are expected to become an active area in nonequilibrium physics and phase transition dynamics. Conservation laws like energy or angular momentum conservation control the time during which the transitions occur. Since the photon induced effects result from weakening or strengthening of the bonding between the atoms or molecules transitions like solid/liquid, etc can be shifted in both directions. Photoinduced transitions will be discussed from a unified point of view. PMID:21411879

  7. Rearrangements of Cycloalkenyl Aryl Ethers.

    PubMed

    Törincsi, Mercedesz; Nagy, Melinda; Bihari, Tamás; Stirling, András; Kolonits, Pál; Novak, Lajos

    2016-01-01

    Rearrangement reactions of cycloalkenyl phenol and naphthyl ethers and the acid-catalyzed cyclization of the resulting product were investigated. Claisen rearrangement afforded 2-substituted phenol and naphthol derivatives. Combined Claisen and Cope rearrangement resulted in the formation of 4-substituted phenol and naphthol derivatives. In the case of cycloocthylphenyl ether the consecutive Claisen and Cope rearrangements were followed by an alkyl migration. The mechanism of this novel rearrangement reaction is also discussed. PMID:27104504

  8. Wolff-Parkinson-White syndrome and sudden cardiac death.

    PubMed

    Prystowsky, E N; Fananapazir, L; Packer, D L; Thompson, K A; German, L D

    1987-01-01

    Every year, individuals with no history of heart disease succumb to sudden cardiac death (SCD). Pathologic examination of the hearts usually reveals various forms of heart disease as hypertrophic cardiomyopathy or coronary artery disease. In other cases, however, there is no obvious structural heart disease, and it is possible that some of these individuals died because of a cardiac arrhythmia involving an accessory pathway. If this were the case, the most likely scenario would be onset of atrioventricular reciprocating tachycardia (AVRT), degeneration of the AVRT into atrial fibrillation with a rapid ventricular response over the accessory pathway, and subsequent death caused by the development of ventricular fibrillation. Although these events have been documented, albeit rarely, during intracardiac electrophysiologic studies, in reality very little is known about the natural history of asymptomatic and untreated patients with Wolff-Parkinson-White (WPW) syndrome. In fact, SCD in a previously asymptomatic patient with WPW syndrome is probably relatively rare. Whether asymptomatic WPW patients should undergo electrophysiologic or pharmacologic testing to determine their 'potential' to develop serious cardiac arrhythmias is controversial. The present paucity of data concerning the natural history of WPW syndrome in asymptomatic patients militates against successful identification of those patients who are at risk for sudden death. Long-term prospective studies are necessary to clarify which asymptomatic patients with WPW syndrome require treatment. PMID:3621280

  9. [Sudden death in the Wolff-Parkinson-White syndrome].

    PubMed

    García-Cosío Mir, F

    1989-04-01

    Clinical electrophysiologic studies in patients with Wolff-Parkinson-White syndrome (WPW) suffering from ventricular fibrillation have shown a high prevalence of short anterograde refractory period of the accessory pathway (less than or equal to 250 ms), short preexcited RR intervals during atrial fibrillation (less than or equal to 250 ms), and multiple accessory pathways. Unfortunately the specificity of these findings is low, as they are present in almost 50% of patients with WPW without a history of ventricular fibrillation, and in 17% of patients with asymptomatic WPW. Pharmacologic and exercise testing detect a population of WPW with a low probability of having a short anterograde refractory period of the accessory pathway, but don't rule-out the ability of these patients to develop very short RR intervals during atrial fibrillation. Natural history studies show that sudden death in WPW occurs with an incidence less than or equal to 1:1,000 per year. The low predictive value of electrophysiologic and noninvasive studies for sudden death, makes then a poor means for screening patients at risk. Some clinical factors, such as the frequency of tachycardias and/or the detection of episodes of atrial flutter or fibrillation are markers of higher sudden death risk, and indications for aggressive electrophysiologic evaluation. PMID:2675223

  10. Parallelization of the Wolff single-cluster algorithm.

    PubMed

    Kaupuzs, J; Rimsāns, J; Melnik, R V N

    2010-02-01

    A parallel [open multiprocessing (OpenMP)] implementation of the Wolff single-cluster algorithm has been developed and tested for the three-dimensional (3D) Ising model. The developed procedure is generalizable to other lattice spin models and its effectiveness depends on the specific application at hand. The applicability of the developed methodology is discussed in the context of the applications, where a sophisticated shuffling scheme is used to generate pseudorandom numbers of high quality, and an iterative method is applied to find the critical temperature of the 3D Ising model with a great accuracy. For the lattice with linear size L=1024, we have reached the speedup about 1.79 times on two processors and about 2.67 times on four processors, as compared to the serial code. According to our estimation, the speedup about three times on four processors is reachable for the O(n) models with n> or =2. Furthermore, the application of the developed OpenMP code allows us to simulate larger lattices due to greater operative (shared) memory available. PMID:20365669

  11. The cubyl cation rearrangements.

    PubMed

    Jalife, Said; Mondal, Sukanta; Cabellos, Jose Luis; Martinez-Guajardo, Gerardo; Fernandez-Herrera, Maria A; Merino, Gabriel

    2016-02-25

    Born-Oppenheimer molecular dynamics simulations and high-level ab initio computations predict that the cage-opening rearrangement of the cubyl cation to the 7H(+)-pentalenyl cation is feasible in the gas phase. The rate-determining step is the formation of the cuneyl cation with an activation barrier of 25.3 kcal mol(-1) at the CCSD(T)/def2-TZVP//MP2/def2-TZVP level. Thus, the cubyl cation is kinetically stable enough to be formed and trapped at moderate temperatures, but it may be rearranged at higher temperatures. PMID:26880646

  12. [Ventricular fibrillation in Wolff-Parkinson-White syndrome. Predictive factors].

    PubMed

    Attoyan, C; Haissaguerre, M; Dartigues, J F; Le Métayer, P; Warin, J F; Clémenty, J

    1994-07-01

    The incidence of sudden death in the Wolff-Parkinson-White (WPW) syndrome is not well documented and probably underestimated. This retrospective study concerned 28 consecutive patients presenting with ventricular fibrillation either spontaneously (20) or during electrophysiological investigation (8) but whose characteristics allowed them to be assimilated into a single group. Their clinical and electrophysiological characteristics were compared with those of 60 consecutive patients with the WPW syndrome who had documented atrial fibrillation (and even reciprocating tachycardia) but never ventricular fibrillation. There were no significant differences between the two groups with respect to the following clinical parameters: sex, duration of symptoms, the type of tachycardia previously recorded, history of syncope and presence of underlying cardiac disease. With respect to the electrophysiological data, there were no differences in the point of anterograde block, the effective anterograde refractory period of the accessory pathway, the effective and functional refractory periods of the right atrium and atrial vulnerability. On the other hand, a significant difference was observed in the age of patients with ventricular fibrillation (29 +/- 13 years vs 36 +/- 12 years; p < 0.02), the prevalence of multiple accessory pathways (25% vs 7%; p < 0.04) with a dominant localisation in the postero-septal region (75% vs 47%, p < 0.026), preexcitation during exercise stress testing and under antiarrhythmic therapy (95% vs 68%, p < 0.037). The most discriminating parameter was the shorter RR interval during atrial fibrillation (172 +/- 23 ms vs 230 +/- 50 ms, p < 0.008). Multivariate analysis only showed one independent predictive factor: the minimum preexcited RR interval.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7702432

  13. The history of the wolff-Parkinson-white syndrome.

    PubMed

    Scheinman, Melvin M

    2012-07-01

    While Drs Wolff, Parkinson, and White fully described the syndrome in 1930, prior case reports had described the essentials. Over the ensuing century this syndrome has captivated the interest of anatomists, clinical cardiologists, and cardiac surgeons. Stanley Kent described lateral muscular connections over the atrioventricular (AV) groove which he felt were the normal AV connections. The normal AV connections were, however, clearly described by His and Tawara. True right-sided AV connections were initially described by Wood et al., while Öhnell first described left free wall pathways. David Scherf is thought to be the first to describe our current understanding of the pathogenesis of the WPW syndrome in terms of a re-entrant circuit involving both the AV node-His axis as well as the accessory pathway. This hypothesis was not universally accepted, and many theories were applied to explain the clinical findings. The basics of our understanding were established by the brilliant work of Pick, Langendorf, and Katz who by using careful deductive analysis of ECGs were able to define the basic pathophysiological processes. Subsequently, Wellens and Durrer applied invasive electrical stimulation to the heart in order to confirm the pathophysiological processes. Sealy and his colleagues at Duke University Medical Center were the first to successfully surgically divide an accessory pathway and ushered in the modern era of therapy for these patients. Morady and Scheinman were the first to successfully ablate an accessory pathway (posteroseptal) using high-energy direct-current shocks. Subsequently Jackman, Kuck, Morady, and a number of groups proved the remarkable safety and efficiency of catheter ablation for pathways in all locations using radiofrequency energy. More recently, Gollob et al. first described the gene responsible for a familial form of WPW. The current ability to cure patients with WPW is due to the splendid contributions of individuals from diverse

  14. Nature and mechanism of the photoinduced spin transition in [Fe(PM-BiA){sub 2}(NCS){sub 2}

    SciTech Connect

    Ichiyanagi, K.; Hebert, J.; Toupet, L.; Cailleau, H.; Collet, E.

    2006-02-01

    We report the investigation of a prototype cooperative photoinduced spin transition in [Fe(PM-BiA){sub 2}(NCS){sub 2}] by x-ray diffraction. The structural rearrangement accompanying the change of an electronic state between the low spin and the photoinduced out-of-equilibrium high spin phases is similar to the one occurring around the phase transition at thermal equilibrium. The cooperative behavior of the light-induced optical hysteresis and light-induced thermal hysteresis phenomena investigated here show a strong similarity with thermal hysteresis around first-order phase transitions, since they are driven by a domain nucleation process.

  15. Phosphonate–phosphinate rearrangement.

    PubMed

    Qian, Renzhe; Roller, Alexander; Hammerschmidt, Friedrich

    2015-01-16

    LiTMP metalated dimethyl N-Boc-phosphoramidates derived from 1-phenylethylamine and 1,2,3,4-tetrahydronaphthalen-1-ylamine highly selectively at the CH3O group to generate short-lived oxymethyllithiums. These isomerized to diastereomeric hydroxymethylphosphonamidates (phosphate–phosphonate rearrangement). However, s-BuLi converted the dimethyl N-Boc-phosphoramidate derived from 1-phenylethylamine to the N-Boc α-aminophosphonate preferentially. Only s-BuLi deprotonated dimethyl hydroxymethylphosphonamidates at the benzylic position and dimethyl N-Boc α-aminophosphonates at the CH3O group to induce phosphonate–phosphinate rearrangements. In the former case, the migration of the phosphorus substituent from the nitrogen to the carbon atom followed a retentive course with some racemization because of the involvement of a benzyllithium as an intermediate. PMID:25525945

  16. Photoinduced Biohydrogen Production from Biomass

    PubMed Central

    Amao, Yutaka

    2008-01-01

    Photoinduced biohydrogen production systems, coupling saccharaides biomass such as sucrose, maltose, cellobiose, cellulose, or saccharides mixture hydrolysis by enzymes and glucose dehydrogenase (GDH), and hydrogen production with platinum colloid as a catalyst using the visible light-induced photosensitization of Mg chlorophyll-a (Mg Chl-a) from higher green plant or artificial chlorophyll analog, zinc porphyrin, are introduced. PMID:19325796

  17. Photo-induced isotopic fractionation

    NASA Astrophysics Data System (ADS)

    Miller, Charles E.; Yung, Yuk L.

    2000-12-01

    This paper presents a systematic method for the analysis of photo-induced isotopic fractionation. The physical basis for this fractionation mechanism centers on the fact that isotopic substitution alters the energy levels, molecular symmetries, spin statistical weights and other fundamental molecular properties, producing spectroscopic signatures distinguishable from that of the parent isotopomer. These mass-dependent physical properties are identical to those invoked by Urey to explain stable isotope fractionation in chemical systems subject to thermodynamic equilibrium. Photo-induced isotopic fractionation is a completely general phenomenon and should be observable in virtually all gas phase photochemical systems. Water photo-induced isotopic fractionation has been examined in detail using experimental and theoretical data. These results illustrate the salient features of this fractionation mechanism for molecules possessing continuous UV absorption spectra and unit photodissociation quantum yields. Using the photo-induced isotopic fractionation methodology in conjunction with standard photochemical models, we predict substantial deuterium enrichment of water vapor in the planetary atmospheres of Earth and Mars.

  18. [A concise history of the Wolff-Parkinson-White syndrome].

    PubMed

    Fazekas, Tamás

    2006-01-01

    In a paper entitled Bundle-branch block with short P-R interval in healthy young people prone to paroxysmal tachycardia (Am Heart J 1930; 5: 685-704), Dr. Louis Wolff (1898-1972), Sir John Parkinson (1885-1976) and Paul Dudley White (1886-1973) described an intricate syndrome. Prior case reports had already pointed out the essentials of this entity, which has borne the eponym (WPW syndrome) since the publication by Levine and Beeson (Am Heart J 1941; 22: 401-409). It was long thought that the first patient with a short PR interval, delta-wave-induced widening of the QRS complex and paroxysmal supraventricular tachycardia (PSVT) was described by Cohn and Fraser in the prestigious cardiological journal edited by Sir Thomas Lewis (1881-1945) in London, UK (Heart 1913/1914; 5: 93-107). Shortly afterwards, Dr János Angyán (1886-1969), a school-founder chairman of medicine (1923-1959) at the University of Pécs, Hungary, also published a clear-cut case of intermittent WPW syndrome in the German periodical Zentralblatt für Herz- und Gefässkrankheiten (1914; 6: 345-349]. In fact, Angyán should be considered the first Hungarian "cardiologist" who dealt steadily with heart diseases and rhythm disturbances. Quite reently, thanks to the activities of Dr Georg von Knorre, Rostock (PACE 2005; 28: 228-230) we have learnt that the earliest documented case of ECGs with ventricular preexcitation and PSVT ("Herzjagen") was published by August Hoffmann (1862-1929) in the 2 Nov 1909 issue of Münchener Medizinische Wochenschrift (56: 2259-2262; Figures 10 and 11). Hoffmann worked as an internist/neurologist and was director of the university hospital in Düsseldorf, Germany. The first successful surgical division of an atrioventricular accessory pathway (bundle of Kent), by Sealy and his coworkers at the Duke University Medical Center in 1967, led to the modern era of curative transcatheter ablation for WPW patients by radiofrequency alternative current or, nowadays, by

  19. Wolff-Michael Roth's passibility: at the limits of the constructivist metaphor: a book review

    NASA Astrophysics Data System (ADS)

    Brendel, Michelle

    2014-12-01

    Wolff-Michael Roth deconstructs the preeminent role conceded to constructivism in Science Education and demonstrates how we learn and know through pain, suffering, love or passion. This review explores his book "Passibility: At the Limits of the Constructivist Metaphor" through the eyes of an outsider to the world of science education.

  20. Studies in a newborn infant with supraventricular tachycardia and Wolff-Parkinson-White syndrome.

    PubMed Central

    Kaye, H H; Reid, D S; Tynan, M

    1975-01-01

    A neonatal patient with Wolff-Parkinson-White type A and supraventricular tachycardia is described. Demonstration of the mechanism of the tachycardia and its termination were achieved using intracardiac electrography and cardiac pacing. Quantitative left ventricular angiography and echocardiography showed impaired left ventricular function following the arrhythmia. Serial echocardiograms demonstrated the subsequent return to normal left ventricular performance. Images PMID:1138737

  1. Subjectivity and Cultural Adjustment in Mathematics Education: A Response to Wolff-Michael Roth

    ERIC Educational Resources Information Center

    Brown, Tony

    2012-01-01

    In this volume, Wolff-Michael Roth provides a critical but partial reading of Tony Brown's book "Mathematics Education and Subjectivity". The reading contrasts Brown's approach with Roth's own conception of subjectivity as derived from the work of Vygotsky, in which Roth aims to "reunite" psychology and sociology. Brown's book, however, focuses on…

  2. Alternating Wolff-Parkinson-White syndrome associated with attack of angina

    SciTech Connect

    Mangiafico, R.A.; Petralito, A.; Grimaldi, D.R. )

    1990-07-01

    In a patient with Wolff-Parkinson-White syndrome and an inferior-posterior bypass tract, transient restoration of normal conduction occurred during an attack of angina. The ECG pattern of inferior posterior ischemia was present when the conduction was normal. Thallium scintigraphy showed a reversible posterolateral perfusion defect. The possible mechanisms for production of intermittent preexcitation are discussed.

  3. Normalization of reverse redistribution of thallium-201 with procainamide pretreatment in Wolff-Parkinson-White syndrome

    SciTech Connect

    Nii, T.; Nakashima, Y.; Nomoto, J.; Hiroki, T.; Ohshima, F.; Arakawa, K. )

    1991-03-01

    Stress thallium-201 myocardial perfusion imaging was performed in a patient with Wolff-Parkinson-White syndrome. Reverse redistribution phenomenon was observed in the absence of coronary artery disease. This seems to be the first report of normalization of this phenomenon in association with reversion of accessory pathway to normal atrioventricular conduction after pretreatment with procainamide.

  4. How to maintain the oral health of a child with Wolff-Parkinson-White syndrome: a case report

    PubMed Central

    2014-01-01

    Introduction Wolff-Parkinson-White syndrome is one of the most important disorders of the heart conduction system. It is caused by the presence of an abnormal accessory electrical conduction pathway between the atria and the ventricles. Case presentation In the present report, we describe the correct oral health management of a 12-year-old Caucasian girl with Wolff-Parkinson-White syndrome. Conclusions We successfully undertook the dental care of a girl with Wolff-Parkinson-White syndrome, which we describe here. PMID:25269932

  5. Photoinduced transformation of UVR8 monitored by vibrational and fluorescence spectroscopy.

    PubMed

    Heilmann, Monika; Christie, John M; Kennis, John T M; Jenkins, Gareth I; Mathes, Tilo

    2015-02-01

    Tryptophan residues at the dimer interface of the plant photoreceptor UVR8 promote monomerisation after UV-B absorption via a so far unknown mechanism. Using FTIR spectroscopy we assign light-induced structural transitions of UVR8 mainly to amino acid side chains without major transformations of the secondary structure of the physiologically relevant C-terminal extension. Additionally, we assign the monomerisation associated increase and red shift of the UVR8 tryptophan emission to a photoinduced rearrangement of tryptophan side chains and a relocation of the aspartic acid residues D96 and D107, respectively. By illumination dependent emission spectroscopy we furthermore determined the quantum yield of photoinduced monomerisation to 20 ± 8%. PMID:25274012

  6. Utility of unipolar recordings for complex Wolff-Parkinson-White ablation.

    PubMed

    Sundaram, Ponnusamy Shunmuga; Sra, Jasbir

    2015-01-01

    Radiofrequency ablation has been shown to be a safe and effective treatment strategy for the management of symptomatic patients with Wolff-Parkinson-White syndrome. It is supported by a success rate of 95% and a recurrence rate of less than 5%. However, ablation of accessory pathways can be challenging at times. The causes for failure can be grouped into three categories - unusual location of the pathway, technical difficulties in delivering the ablation and localization error [1]. In this case report we are reporting a case of a young male who presented to us with symptomatic Wolff-Parkinson-White syndrome with two failed prior ablations at another institution. This case illustrates the importance of knowing accurate localization and course of the accessory pathway by utilizing the unipolar and bipolar electrograms simultaneously during radiofrequency ablation. PMID:26937099

  7. Multiple cardiac rhabdomyomas, wolff-Parkinson-white syndrome, and tuberous sclerosis: an infrequent combination.

    PubMed

    Castilla Cabanes, Elena; Lacambra Blasco, Isaac

    2014-01-01

    Cardiac rhabdomyomas are benign cardiac tumours and are often associated with tuberous sclerosis. They are often asymptomatic with spontaneus regresion but can cause heart failure, arrhythmias, and obstruction. There have also been a few isolated reports of Wolff-Parkinson-White syndrome occurring in association with tuberous sclerosis and the great majority has been detected in patients with concomitant rhabdomyomas. We report a 12-day-old infant girl with tuberous sclerosis who presented with intraparietal and intracavitary rhabdomyomas with a Wolff-Parkinson-White syndrome (WPW). She represents one of the few published cases of WPW syndrome and tuberous sclerosis and particularly interesting because of intramural rhabdomyomas regression with persistent intracavitary rhabdomyomas after two years of followup. PMID:25328743

  8. [WPW cases in the literature prior to the publication of Wolff, Parkinson and White in 1930].

    PubMed

    von Knorre, G H

    2006-03-01

    In 1930, Wolff, Parkinson and White described the clinical entity of what is today known as the preexcitation or WPW syndrome. In the preceding literature, the authors found four comparable cases. Later on, seven further cases published prior to 1930 were discovered. An analysis of the altogether eleven cases displays that, in addition to the anomalous ECG in sinus rhythm, nearly all typical electrocardiographic findings during the tachyarrhythmias are found in this early literature. As tachycardia ECGs especially help to understand the mechanism of the WPW syndrome, the question is discussed whether already Wolff, Parkinson and White would have been able to give the correct interpretation of the mechanism if they had taken into consideration their own tachycardia ECGs as well as those known to them from the literature. PMID:16547659

  9. [Atrioventricular and ventriculoatrial conduction in patients operated on for the Wolff-Parkinson-White syndrome].

    PubMed

    Colín, L; Dorado, M; Iturralde, P; Romero, L; Kershenovich, S; de Micheli, A; Barragán, R; Ramírez, S; González-Hermosillo, J A

    1992-01-01

    Over the last decade the surgical treatment of the Wolff-Parkinson-White syndrome has been well accepted. It is important to make an early diagnosis for surgical success. For this purpose we utilized programmed electrical stimulation to assess the functional characteristics of atrioventricular and ventriculoatrial conduction in our post-operative patients. In 55% of the cases we found accelerated nodal conduction. Programmed electrical stimulation correctly identified 90% of successfully treated patients. We did not found any false positive curve, therefore, this method has a high specificity. We concluded that in post-operative patients with the Wolff-Parkinson-White syndrome: 1- There is a high incidence of accelerated nodal conduction and 2- programmed electrical stimulation can correctly identify most of the patients who were successfully treated. PMID:1632713

  10. The Discovery of Binary Asteroid 5674 Wolff at Isaac Aznar Observatory

    NASA Astrophysics Data System (ADS)

    Aznar Macias, Amadeo; Pravec, Petr; Oey, Julian; Groom, Roger

    2016-07-01

    We report on the discovery that minor planet 5674 Wolff is a fully-synchronous binary system with an orbital period of 93.7 ± 0.2 h. The combined primary+secondary rotation amplitude is 0.52 ± 0.02 mag. A lower limit on the secondary-to-primary mean diameter ratio is D2/D1 = 0.80.

  11. A case of surgically corrected Wolff-Parkinson-White syndrome. Clinical and histological data.

    PubMed Central

    Rossi, L; Thiene, G; Knippel, M

    1978-01-01

    A case of type B Wolff-Parkinson-White syndrome, with intractable atrial fibrillation, underwent surgical division of a right-sided accessory atrioventricular bundle of Kent. Pre-excitation and complicating tachyarrhythmias were henceforth abolished for 6 weeks, when the patient died of infective endocarditis. Histological examination showed a divided Kent's accessory atrioventricular pathway and apparently functionless James and Mahaim fibres. Images PMID:656230

  12. Photoinduced molecular reorientation of absorbing liquid crystals

    NASA Astrophysics Data System (ADS)

    Marrucci, L.; Paparo, D.

    1997-08-01

    The phenomenon of photoinduced molecular reorientation of absorbing nematic liquid crystals is analyzed in a macroscopic general framework and with a specific molecular model. The photoinduced torque responsible for the reorientation is shown to describe a transfer of angular momentum from the molecule center-of-mass degrees of freedom to the rotational ones, mediated by molecular friction. As a consequence, a photoinduced stress tensor is predicted to develop together with the torque in the illuminated fluid. A molecular expression of the photoinduced torque is derived with a rigorous procedure, valid both for a pure material and for a dye-liquid-crystal mixture. This torque expression corrects those reported in previous works on the same subject. The photoinduced torque is evaluated analytically in a simple approximate limit.

  13. Claisen thermally rearranged (CTR) polymers.

    PubMed

    Tena, Alberto; Rangou, Sofia; Shishatskiy, Sergey; Filiz, Volkan; Abetz, Volker

    2016-07-01

    Thermally rearranged (TR) polymers, which are considered the next-generation of membrane materials because of their excellent transport properties and high thermal and chemical stability, are proven to have significant drawbacks because of the high temperature required for the rearrangement and low degree of conversion during this process. We demonstrate that using a [3,3]-sigmatropic rearrangement, the temperature required for the rearrangement of a solid glassy polymer was reduced by 200°C. Conversions of functionalized polyimide to polybenzoxazole of more than 97% were achieved. These highly mechanically stable polymers were almost five times more permeable and had more than two times higher degrees of conversion than the reference polymer treated under the same conditions. Properties of these second-generation TR polymers provide the possibility of preparing efficient polymer membranes in a form of, for example, thin-film composite membranes for various gas and liquid membrane separation applications. PMID:27482538

  14. Claisen thermally rearranged (CTR) polymers

    PubMed Central

    Tena, Alberto; Rangou, Sofia; Shishatskiy, Sergey; Filiz, Volkan; Abetz, Volker

    2016-01-01

    Thermally rearranged (TR) polymers, which are considered the next-generation of membrane materials because of their excellent transport properties and high thermal and chemical stability, are proven to have significant drawbacks because of the high temperature required for the rearrangement and low degree of conversion during this process. We demonstrate that using a [3,3]-sigmatropic rearrangement, the temperature required for the rearrangement of a solid glassy polymer was reduced by 200°C. Conversions of functionalized polyimide to polybenzoxazole of more than 97% were achieved. These highly mechanically stable polymers were almost five times more permeable and had more than two times higher degrees of conversion than the reference polymer treated under the same conditions. Properties of these second-generation TR polymers provide the possibility of preparing efficient polymer membranes in a form of, for example, thin-film composite membranes for various gas and liquid membrane separation applications. PMID:27482538

  15. Radical Smiles Rearrangement: An Update.

    PubMed

    Allart-Simon, Ingrid; Gérard, Stéphane; Sapi, Janos

    2016-01-01

    Over the decades the Smiles rearrangement and its variants have become essential synthetic tools in modern synthetic organic chemistry. In this mini-review we summarized some very recent results of the radical version of these rearrangements. The selected examples illustrate the synthetic power of this approach, especially if it is incorporated into a domino process, for the preparation of polyfunctionalized complex molecules. PMID:27399654

  16. Immunoglobulin λ Gene Rearrangement Can Precede κ Gene Rearrangement

    DOE PAGESBeta

    Berg, Jörg; Mcdowell, Mindy; Jäck, Hans-Martin; Wabl, Matthias

    1990-01-01

    Imore » mmunoglobulin genes are generated during differentiation of B lymphocytes by joining gene segments. A mouse pre-B cell contains a functional immunoglobulin heavy-chain gene, but no light-chain gene. Although there is only one heavy-chain locus, there are two lightchain loci: κ and λ .It has been reported that κ loci in the germ-line configuration are never (in man) or very rarely (in the mouse) present in cells with functionally rearranged λ -chain genes. Two explanations have been proposed to explain this: (a) the ordered rearrangement theory, which postulates that light-chain gene rearrangement in the pre-B cell is first attempted at the κ locus, and that only upon failure to produce a functional κ chain is there an attempt to rearrange the λ locus; and (b) the stochastic theory, which postulates that rearrangement at the λ locus proceeds at a rate that is intrinsically much slower than that at the κ locus. We show here that λ -chain genes are generated whether or not the κ locus has lost its germ-line arrangement, a result that is compatible only with the stochastic theory.« less

  17. Natural history of Wolff-Parkinson-White syndrome diagnosed in childhood.

    PubMed

    Cain, Nicole; Irving, Claire; Webber, Steven; Beerman, Lee; Arora, Gaurav

    2013-10-01

    Wolff-Parkinson-White (WPW) syndrome carries a risk for symptomatic arrhythmias and sudden death. The aim of this study was to examine the natural history of patients with Wolff-Parkinson-White syndrome diagnosed in childhood followed longitudinally at a single institution. The study population consisted of 446 patients. The median age of diagnosis was 7 years, and 61% were male. Associated heart disease was present in 40 patients (9%). Modes of presentation included supraventricular tachycardia (38%), palpitations (22%), chest pain (5%), syncope (4%), atrial fibrillation (0.4%), sudden death (0.2%), and incidental findings (26%); data were unavailable in 4%. During the study period, a total of 243 patients (54%) had supraventricular tachycardia, and 7 patients (1.6%) had atrial fibrillation. Of patients who presented at ≤3 months of age, 35% had resolution of manifest preexcitation compared with 5.8% who presented at >3 months of age (p <0.0001). There were 6 sudden deaths (1.3%), with an incidence of 2.8 per 1,000 patient-years. Two of these patients had structurally normal hearts (incidence 1.1 per 1,000 patient-years). Four of these patients had associated heart disease (incidence 27 per 1,000 patient-years) (p <0.01). In conclusion, in a large population of patients with Wolff-Parkinson-White syndrome diagnosed in childhood, 64% had symptoms at presentation, and an additional 20% developed symptoms during follow-up. There were 6 sudden deaths (1.3%), with an overall incidence of 1.1 per 1,000 patient-years in patients with structurally normal hearts and 27 per 1,000 patient-years in patients with associated heart disease. PMID:23827401

  18. Radiofrequency catheter ablation in patients with Wolff-Parkinson-White syndrome.

    PubMed Central

    Thakur, R K; Klein, G J; Yee, R

    1994-01-01

    OBJECTIVE: To report on the experience with radiofrequency catheter ablation of accessory atrioventricular pathways in patients with Wolff-Parkinson-White syndrome in terms of the duration of fluoroscopy exposure to the patient and the operator and the effect of accessory-pathway location and operator experience on the success rate. DESIGN: Retrospective review. SETTING: Tertiary care university hospital. PATIENTS: Two hundred consecutive patients with Wolff-Parkinson-White syndrome who underwent radiofrequency catheter ablation between September 1990 and June 1992. INTERVENTIONS: Electrophysiologic study and radiofrequency catheter ablation. MAIN OUTCOME MEASURES: Success rate, duration of fluoroscopy, complications and long-term follow-up. RESULTS: Of the 224 accessory pathways in the 200 patients 135 were left free wall, 47 posteroseptal, 32 right free wall and 10 anteroseptal. The overall success rate increased from 53% in the first 3 months of the study period to 96% in the last 3 months. The success rate depended on the location of the accessory pathway. The duration of fluoroscopic exposure decreased from 50 (standard deviation [SD] 21) minutes in the first 3 months to 40 (SD 15) minutes in the last 3 months (p < 0.05). Complications occurred in 3.5% of the patients; they included hemopericardium, cerebral embolism, perforation of the right atrial wall, air embolism in a coronary artery and hematoma at the arterial perforation site. None of the complications resulted in death. CONCLUSIONS: With experience, radiofrequency catheter ablation of accessory pathways can have an overall success rate of more than 95% and a complication rate of less than 4%. Such rates make this procedure suitable for first-line therapy for patients with Wolff-Parkinson-White syndrome. Images Fig. 1 PMID:8087753

  19. Capturing ultrafast photoinduced local structural distortion of BiFeO3

    SciTech Connect

    Wen, Haidan; Sassi, Michel; Luo, Zhenlin; Adamo, Carolina; Schlom, Darrell G.; Rosso, Kevin M.; Zhang, Xiaoyi

    2015-10-14

    The interaction of light with materials is an intensively studied research forefront, in which the coupling of radiation energy to selective degrees of freedom offers contact-free tuning of functionalities on ultrafast time scales. Capturing the fundamental processes and understanding the mechanism of photoinduced structural rearrangement are essential to applications such as photo-active actuators and efficient photovoltaic devices. Using ultrafast x-ray absorption spectroscopy aided by density functional theory calculations, we reveal the local structural arrangement around the transition metal atom in a unit cell of the photoferroelectric archetype BiFeO3 film. The out-of-plane elongation of the unit cell is accompanied by the in-plane shrinkage with minimal change of interaxial lattice angles upon photoexcitation. This anisotropic elastic deformation of the unit cell is driven by localized electric field as a result of photoinduced charge separation, in contrast to a global lattice constant increase and lattice angle variations as a result of heating. The finding of a photoinduced elastic unit cell deformation elucidates a microscopic picture of photocarrier-mediated non-equilibrium processes in polar materials.

  20. Capturing ultrafast photoinduced local structural distortions of BiFeO3

    DOE PAGESBeta

    Wen, Haidan; Sassi, Michel JPC; Luo, Zhenlin; Adamo, Carolina; Schlom, Darrell; Rosso, Kevin M.; Zhang, Xiaoyi

    2015-10-14

    The interaction of light with materials is an intensively studied research forefront, in which the coupling of radiation energy to selective degrees of freedom offers contact-free tuning of functionalities on ultrafast time scales. Capturing the fundamental processes and understanding the mechanism of photoinduced structural rearrangement are essential to applications such as photo-active actuators and efficient photovoltaic devices. Using ultrafast x-ray absorption spectroscopy aided by density functional theory calculations, we reveal the local structural arrangement around the transition metal atom in a unit cell of the photoferroelectric archetype BiFeO3 film. The out-of-plane elongation of the unit cell is accompanied by themore » in-plane shrinkage with minimal change of interaxial lattice angles upon photoexcitation. This uniaxial elastic deformation of the unit cell is driven by localized electric field as a result of photoinduced charge separation, in contrast to a global lattice constant increase and lattice angle variations as a result of heating. The finding of a photoinduced elastic unit cell deformation elucidates a microscopic picture of photocarrier-mediated nonequilibrium processes in polar materials.« less

  1. Capturing ultrafast photoinduced local structural distortions of BiFeO3

    SciTech Connect

    Wen, Haidan; Sassi, Michel JPC; Luo, Zhenlin; Adamo, Carolina; Schlom, Darrell; Rosso, Kevin M.; Zhang, Xiaoyi

    2015-10-14

    The interaction of light with materials is an intensively studied research forefront, in which the coupling of radiation energy to selective degrees of freedom offers contact-free tuning of functionalities on ultrafast time scales. Capturing the fundamental processes and understanding the mechanism of photoinduced structural rearrangement are essential to applications such as photo-active actuators and efficient photovoltaic devices. Using ultrafast x-ray absorption spectroscopy aided by density functional theory calculations, we reveal the local structural arrangement around the transition metal atom in a unit cell of the photoferroelectric archetype BiFeO3 film. The out-of-plane elongation of the unit cell is accompanied by the in-plane shrinkage with minimal change of interaxial lattice angles upon photoexcitation. This uniaxial elastic deformation of the unit cell is driven by localized electric field as a result of photoinduced charge separation, in contrast to a global lattice constant increase and lattice angle variations as a result of heating. The finding of a photoinduced elastic unit cell deformation elucidates a microscopic picture of photocarrier-mediated nonequilibrium processes in polar materials.

  2. Capturing ultrafast photoinduced local structural distortions of BiFeO3

    PubMed Central

    Wen, Haidan; Sassi, Michel; Luo, Zhenlin; Adamo, Carolina; Schlom, Darrell G.; Rosso, Kevin M.; Zhang, Xiaoyi

    2015-01-01

    The interaction of light with materials is an intensively studied research forefront, in which the coupling of radiation energy to selective degrees of freedom offers contact-free tuning of functionalities on ultrafast time scales. Capturing the fundamental processes and understanding the mechanism of photoinduced structural rearrangement are essential to applications such as photo-active actuators and efficient photovoltaic devices. Using ultrafast x-ray absorption spectroscopy aided by density functional theory calculations, we reveal the local structural arrangement around the transition metal atom in a unit cell of the photoferroelectric archetype BiFeO3 film. The out-of-plane elongation of the unit cell is accompanied by the in-plane shrinkage with minimal change of interaxial lattice angles upon photoexcitation. This anisotropic elastic deformation of the unit cell is driven by localized electric field as a result of photoinduced charge separation, in contrast to a global lattice constant increase and lattice angle variations as a result of heating. The finding of a photoinduced elastic unit cell deformation elucidates a microscopic picture of photocarrier-mediated non-equilibrium processes in polar materials. PMID:26463128

  3. Capturing ultrafast photoinduced local structural distortions of BiFeO3

    NASA Astrophysics Data System (ADS)

    Wen, Haidan; Sassi, Michel; Luo, Zhenlin; Adamo, Carolina; Schlom, Darrell G.; Rosso, Kevin M.; Zhang, Xiaoyi

    2015-10-01

    The interaction of light with materials is an intensively studied research forefront, in which the coupling of radiation energy to selective degrees of freedom offers contact-free tuning of functionalities on ultrafast time scales. Capturing the fundamental processes and understanding the mechanism of photoinduced structural rearrangement are essential to applications such as photo-active actuators and efficient photovoltaic devices. Using ultrafast x-ray absorption spectroscopy aided by density functional theory calculations, we reveal the local structural arrangement around the transition metal atom in a unit cell of the photoferroelectric archetype BiFeO3 film. The out-of-plane elongation of the unit cell is accompanied by the in-plane shrinkage with minimal change of interaxial lattice angles upon photoexcitation. This anisotropic elastic deformation of the unit cell is driven by localized electric field as a result of photoinduced charge separation, in contrast to a global lattice constant increase and lattice angle variations as a result of heating. The finding of a photoinduced elastic unit cell deformation elucidates a microscopic picture of photocarrier-mediated non-equilibrium processes in polar materials.

  4. Capturing ultrafast photoinduced local structural distortions of BiFeO3.

    PubMed

    Wen, Haidan; Sassi, Michel; Luo, Zhenlin; Adamo, Carolina; Schlom, Darrell G; Rosso, Kevin M; Zhang, Xiaoyi

    2015-01-01

    The interaction of light with materials is an intensively studied research forefront, in which the coupling of radiation energy to selective degrees of freedom offers contact-free tuning of functionalities on ultrafast time scales. Capturing the fundamental processes and understanding the mechanism of photoinduced structural rearrangement are essential to applications such as photo-active actuators and efficient photovoltaic devices. Using ultrafast x-ray absorption spectroscopy aided by density functional theory calculations, we reveal the local structural arrangement around the transition metal atom in a unit cell of the photoferroelectric archetype BiFeO3 film. The out-of-plane elongation of the unit cell is accompanied by the in-plane shrinkage with minimal change of interaxial lattice angles upon photoexcitation. This anisotropic elastic deformation of the unit cell is driven by localized electric field as a result of photoinduced charge separation, in contrast to a global lattice constant increase and lattice angle variations as a result of heating. The finding of a photoinduced elastic unit cell deformation elucidates a microscopic picture of photocarrier-mediated non-equilibrium processes in polar materials. PMID:26463128

  5. Catheter ablation of the accessory pathways of the Wolff-Parkinson-White syndrome and its variants.

    PubMed

    Plumb, V J

    1995-01-01

    The basis of arrhythmias in the Wolff-Parkinson-White (WPW) syndrome and its variants is the presence of accessory atrioventricular connections. Those variants include the concealed form of the WPW syndrome, the permanent form of junctional reciprocating tachycardia, and Mahaim preexcitation. In all forms of symptomatic WPW syndrome, catheter ablation of the accessory atrioventricular connections using radiofrequency current has become the treatment of choice. This review traces the development of this therapy, outlines the basics of the technique, summarizes the results reported in the largest series, indicate remaining areas of controversy, and discusses the indications and limitations of radiofrequency ablation therapy. PMID:7871178

  6. Ebstein's anomaly presenting as Wolff-Parkinson white syndrome in a postpartum patient.

    PubMed

    Mathew, S T; Matthew, S T; Federico, G F; Singh, B K

    2003-01-01

    Ebstein's anomaly is a common congenital abnormality in the Wolff-Parkinson white syndrome (WPW). The term WPW is applied to patients with both preexcitation on ECG and paroxysmal tachycardias. In this case review, we describe a female with a history of intermittent palpitations who presented in the postpartum period with WPW. Subsequent testing revealed an underlying Ebstein's anomaly. In the United States, heart disease is responsible for 10% of maternal deaths. Although pregnancy is well known to exacerbate symptoms in patients with WPW, postpartum exacerbation has not been clearly described. This unusual case suggests that monitoring beyond the peurperium would be advisable in patients at risk to develop malignant tachyarrhythmias. PMID:12852798

  7. Spinal Anaesthesia is Safe in a Patient with Wolff-Parkinson-White Syndrome Undergoing Evacuation of Molar Pregnancy

    PubMed Central

    Pujari, Vinayak S

    2016-01-01

    Wolff-Parkinson-White (WPW) syndrome is an uncommon cardiac condition where there is an abnormal band of atrial tissue connecting atria and ventricles which can electrically bypass atrioventricular node. The anaesthetic management in these patients is challenging as life threatening complications can occur perioperatively like paroxysmal supraventricular tachycardia and atrial fibrillation. Also, regional anaesthetic technique like subarachnoid block is a safe and cost effective alternative to general anaesthesia as it avoids polypharmacy. We report the successful anaesthetic management of Wolff Parkinson White syndrome in a primi with hydatiform mole posted for suction and evacuation. PMID:27042562

  8. Spinal Anaesthesia is Safe in a Patient with Wolff-Parkinson-White Syndrome Undergoing Evacuation of Molar Pregnancy.

    PubMed

    Deviseti, Pravalika; Pujari, Vinayak S

    2016-02-01

    Wolff-Parkinson-White (WPW) syndrome is an uncommon cardiac condition where there is an abnormal band of atrial tissue connecting atria and ventricles which can electrically bypass atrioventricular node. The anaesthetic management in these patients is challenging as life threatening complications can occur perioperatively like paroxysmal supraventricular tachycardia and atrial fibrillation. Also, regional anaesthetic technique like subarachnoid block is a safe and cost effective alternative to general anaesthesia as it avoids polypharmacy. We report the successful anaesthetic management of Wolff Parkinson White syndrome in a primi with hydatiform mole posted for suction and evacuation. PMID:27042562

  9. Concomitant Wolff-Parkinson-White and Atrioventricular Nodal Reentrant Tachycardia: Which Pathway to Ablate?

    PubMed Central

    Sarsam, Sinan; Sidiqi, Ibrahim; Shah, Dipak; Zughaib, Marcel

    2015-01-01

    Patient: Male, 54 Final Diagnosis: WPW and AVNRT Symptoms: Palpitations • shorthness of breath Medication: — Clinical Procedure: EP Study/Radiofrequency Ablation Specialty: Cardiology Objective: Rare co-existance of disease or pathology Background: Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common form of supraventricular tachycardia. In contrast, Wolff-Parkinson-White (WPW) pattern consists of an accessory pathway, which may result in the development of ventricular arrhythmias. Frequent tachycardia caused by AVNRT and accessory pathways may play a role in left ventricular systolic dysfunction. Case Report: A 54-year-old man presented with palpitations and acute decompensated congestive heart failure. His baseline EKG showed Wolff-Parkinson-White (WPW) pattern. While hospitalized, he had an episode of atrioventricular nodal reentrant tachycardia (AVNRT). He underwent radiofrequency catheter ablation for AVNRT, and his accessory pathway was also ablated even though its conduction was found to be weak. He was clinically doing well on follow-up visit, with resolution of his heart failure symptoms and normalization of left ventricular function on echocardiography. Conclusions: This case raises the question whether the accessory pathway plays a role in the development of systolic dysfunction, and if there is any role for ablation in patients with asymptomatic WPW pattern. PMID:26655223

  10. Photoinduced toxicity of engineered nanomaterials

    NASA Astrophysics Data System (ADS)

    Jones, Philip Scott

    Engineered nanomaterials including metal, metal oxide and carbon based nanomaterials are extensively used in a wide variety of applications to the extent that their presence in the environment is expected to increase dramatically over the next century. These nanomaterials may be photodegraded by solar radiation and thereby release metal ions into the environment that can produce cytotoxic and genotoxic effects. Photoinduced toxicity experiments are performed exposing human lung epithelial carcinoma cells [H1650] to engineered semiconductor nanoparticles such as CdSe quantum dots and ZnO nanoparticles after exposure to 3, 6, and 9 hours of solar simulated radiation. Cytotoxicity and genotoxicity of the metal ions are evaluated using ZnSO4 and CdCl2 solutions for the MTT assay and Comet assay respectively. The objective of the dissertation is to obtain quantitative information about the environmental transformation of engineered nanomaterials and their mechanism of toxicity. This information is critical for addressing the environmental health and safety risks of engineered nanomaterials to workers, consumers and the environment.

  11. Photoinduced magnetic force between nanostructures

    NASA Astrophysics Data System (ADS)

    Guclu, Caner; Tamma, Venkata Ananth; Wickramasinghe, Hemantha Kumar; Capolino, Filippo

    2015-12-01

    Photoinduced magnetic force between nanostructures, at optical frequencies, is investigated theoretically. Till now optical magnetic effects were not used in scanning probe microscopy because of the vanishing natural magnetism with increasing frequency. On the other hand, artificial magnetism in engineered nanostructures led to the development of measurable optical magnetism. Here two examples of nanoprobes that are able to generate strong magnetic dipolar fields at optical frequency are investigated: first, an ideal magnetically polarizable nanosphere and then a circular cluster of silver nanospheres that has a looplike collective plasmonic resonance equivalent to a magnetic dipole. Magnetic forces are evaluated based on nanostructure polarizabilities, i.e., induced magnetic dipoles, and magnetic-near field evaluations. As an initial assessment on the possibility of a magnetic nanoprobe to detect magnetic forces, we consider two identical magnetically polarizable nanoprobes and observe magnetic forces on the order of piconewtons, thereby bringing it within detection limits of conventional atomic force microscopes at ambient pressure and temperature. The detection of magnetic force is a promising method in studying optical magnetic transitions that can be the basis of innovative spectroscopy applications.

  12. Photoinduced reactions of 1-(dimethylethyl)-2,2-dimethylpropyl and cyclohexyl radicals in low-temperature solids

    NASA Astrophysics Data System (ADS)

    Koizumi, Hitoshi; Takada, Tomoya; Ichikawa, Tsuneki; Lund, Anders

    2001-06-01

    Photoinduced reactions of 1-(dimethylethyl)-2,2-dimethylpropyl and cyclohexyl radicals in 77 K solids were studied by the ESR method. 1-(Dimethylethyl)-2,2-dimethylpropyl is converted to 2,2,4,4-tetramethylpentyl radical with photoirradiation of 254 nm light. A hydrogen atom of methyl groups can hence directly transfer to the radical site at a carbon atom other than an adjacent one in the photoinduced reactions of alkyl radicals. Cyclohexyl radical is converted to cyclopentylmethyl radical with irradiation of 254 nm light. The photolysis of cyclohexyl radical causes C-C bond scission, and results in the formation of 5-hexenyl radical. It is then converted to cyclopentylmethyl radical through intramolecular rearrangement.

  13. Biotransformation and Rearrangement of Laromustine.

    PubMed

    Nassar, Alaa-Eldin F; Wisnewski, Adam V; King, Ivan

    2016-08-01

    This review highlights the recent research into the biotransformations and rearrangement of the sulfonylhydrazine-alkylating agent laromustine. Incubation of [(14)C]laromustine with rat, dog, monkey, and human liver microsomes produced eight radioactive components (C-1 to C-8). There was little difference in the metabolite profile among the species examined, partly because NADPH was not required for the formation of most components, which instead involved decomposition and/or hydrolysis. The exception was C-7, a hydroxylated metabolite, largely formed by CYP2B6 and CYP3A4/5. Liquid chromatography-multistage mass spectrometry (LC-MS(n)) studies determined that collision-induced dissociation, and not biotransformation or enzyme catalysis, produced the unique mass spectral rearrangement. Accurate mass measurements performed with a Fourier-transform ion cyclotron resonance mass spectrometer (FTICR-MS) significantly aided determination of the elemental compositions of the fragments and in the case of laromustine revealed the possibility of rearrangement. Further, collision-induced dissociation produced the loss of nitrogen (N2) and methylsulfonyl and methyl isocyanate moieties. The rearrangement, metabolite/decomposition products, and conjugation reactions were analyzed utilizing hydrogen-deuterium exchange, exact mass, (13)C-labeled laromustine, nuclear magnetic resonance spectroscopy (NMR), and LC-MS(n) experiments to assist with the assignments of these fragments and possible mechanistic rearrangement. Such techniques produced valuable insights into these functions: 1) Cytochrome P450 is involved in C-7 formation but plays little or no role in the conversion of [(14)C]laromustine to C-1 through C-6 and C-8; 2) the relative abundance of individual degradation/metabolite products was not species-dependent; and 3) laromustine produces several reactive intermediates that may produce the toxicities seen in the clinical trials. PMID:27278961

  14. Sensitivity as a Privileged Predictor of Attachment: A Second Perspective of De Wolff and van IJzendoorn's Meta-Analysis

    ERIC Educational Resources Information Center

    Nievar, M. Angela; Becker, Betsy Jane

    2004-01-01

    This secondary analysis of De Wolff and van IJzendoorn's (1997) meta-analysis of maternal behavior and attachment reexamined their conclusion that sensitivity was not a preferred predictor of attachment security. The meta-analysis included 66 studies with 123 effect sizes sorted through a combination of personal choice and homogeneity analysis…

  15. The cytogenetics of mammalian autosomal rearrangements

    SciTech Connect

    Daniel, A.

    1988-01-01

    Combining data from animal and clinical studies with classical cytogenetic observations, the volume provides information on various aspects of mammalian autosomal rearrangements. Topics range from the reproductive consequences to carriers of autosomal rearrangements to the application of structural rearrangements and DNA probes to gene mapping. In addition, the book presents an overview of new perspectives and future directions for research.

  16. Sugammadex Use in a Patient with Wolff-Parkinson-White (WPW) Syndrome

    PubMed Central

    Şahin, Sevtap Hekimoğlu; Öztekin, İlhan; Kuzucuoğlu, Aytuna; Aslanoğlu, Ayça

    2015-01-01

    Background: Wolff-Parkinson-White (WPW) syndrome is a disease associated with episodes of supraventricular tachycardia and ventricular pre-excitation or atrial fibrillation. WPW is characterized by an aberrant electrical conduction pathway between atria and ventricles. Case Report: The major anesthetic problem connected with WPW syndrome is the risk of tachyarrhythmias due to accessory pathway. Therefore, it has been proposed that the aim of anesthetic management should be the avoidance of tachyarrhythmia and sympathetic stimulation. Sugammadex was administered as a neuromuscular reversal agent in this case. To our knowledge, this is the first case report of sugammadex use in a patient with WPW. This report presents a case of general anesthesia management in a patient with WPW syndrome. Conclusion: We think that it is appropriate to use sugammadex to reverse rocuronium for the prevention of sudden hemodynamic changes in patients with WPW who underwent general anesthesia. PMID:26185726

  17. Systemic sclerosis sine scleroderma associated with Wolff-Parkinson-White syndrome.

    PubMed

    Park, Y-W; Woo, H; Yoon, H-J; Park, H-W; Cho, J-G; Shin, S-S; Lee, S-S

    2007-01-01

    The term "systemic sclerosis sine scleroderma" (ssSSc) has been used to designate a rare progressive systemic sclerosis of visceral organs without skin manifestations. A variety of visceral organs, including the gastrointestinal tract, lung, heart, and kidney, can be involved. We describe a case of 59-year-old female patient with both Wolff-Parkinson-White (WPW) syndrome and ssSSc. She was diagnosed as having ssSSc with Raynaud's phenomenon, anti-nuclear antibody (ANA) and anti-topoisomerase antibody positivity, interstitial pulmonary infiltrates, suspected pulmonary hypertension, subclinical oesophageal dysmotility but no skin thickening. She had a history of paroxysmal tachycardia together with Raynaud's phenomenon and exercise-induced dyspnoea. Electrophysiological study confirmed WPW syndrome with left posterior bypass tract. This case highlights cardiac arrhythmia caused by WPW syndrome as a clinical manifestation of the heart in ssSSc. PMID:17454939

  18. [A case of intermittent Wolff-Parkinson-White syndrome caused by high spinal anesthesia].

    PubMed

    Shiroyama, K; Nakagawa, I; Izumi, H; Kurokawa, H; Kuroda, M

    1994-04-01

    We experienced a case of intermittent Wolff-Parkinson-White (WPW) syndrome following spinal anesthesia. This patient had neither any past history of cardiac symptoms nor any abnormal finding in the preoperative electrocardiogram. Soon after spinal anesthesia, the level of anesthesia spread to C6. Both abbreviated PR intervals and delta waves characteristic of WPW syndrome appeared on the electrocardiogram monitor. These abnormal wave-forms continued throughout the operation, but disappeared after three days. This case was diagnosed as intermittent WPW syndrome based upon these observations. High spinal anesthesia effectively blocks the cardiac sympathetic nerve and suppresses the normal atrioventricular conduction. Further, conduction by the accessory pathway is facilitated by the relative excitement of parasympathetic nerve. In the present case, the conduction by the accessory pathway, which had originally been very poor, was transiently promoted by the above-mentioned mechanism, and abnormal wave-forms characteristic of WPW syndrome appeared temporarily in the electrocardiogram. PMID:8189627

  19. Anaesthetic management of a case of Wolff-Parkinson-White syndrome.

    PubMed

    Kabade, Savitri D; Sheikh, Safiya; Periyadka, Bhavya

    2011-07-01

    We report a case of fibroid uterus with Wolff-Parkinson-White (WPW) syndrome in a 48-year-old female, posted for elective hysterectomy. Patient gave history of short recurrent episodes of palpitation and electrocardiograph confirmed the diagnosis of WPW syndrome. The anaesthetic management of these patients is challenging as they are known to develop life threatening tachyarrhythmia like paroxysmal supra-ventricular tachycardia (PSVT) and atrial fibrillation (AF). Epidural anaesthesia is preferred compared to general anaesthesia to avoid polypharmacy, noxious stimuli of laryngoscopy and intubation. To deal with perioperative complications like PSVT and AF, anti-arrhythmic drugs like adenosine, beta blockers and defibrillator should be kept ready. Perioperative monitoring is essential as patients can develop complications. PMID:22013256

  20. Syncope in the Wolff-Parkinson-White syndrome: incidence and electrophysiologic correlates.

    PubMed

    Yee, R; Klein, G J

    1984-05-01

    Syncope in the patient with Wolff-Parkinson-White (WPW) syndrome raises the specter of rapid tachyarrhythmias and the possibility of sudden cardiac death. We reviewed the records of 55 consecutive WPW patients referred for electrophysiologic evaluation of known or suspected arrhythmias to determine the incidence and significance of syncope. Twelve patients (22.6%) reported the occurrence of at least one episode of syncope. In eleven (20%) of these, syncope was preceded by rapid palpitations. Forty-three patients (77.4%) had no syncopal episodes. These two groups did not differ significantly with regard to age, sex, presence of associated cardiac or neurologic disease, drug history or accessory pathway location. There was no significant difference in cycle length of reciprocating tachycardia (syncope = 295.6 +/- 59.8 vs non-syncope = 334.5 +/- 59.6 ms, p less than .5), shortest R-R intervals between preexcited beats (260 +/- 78.6 vs 246.7 +/- 55.4 ms, p less than .5) and average R-R interval (364.4 +/- 37.9 vs 367.4 +/- 77.5 ms, p less than .5) measured during atrial fibrillation. The anterograde effective refractory period of the accessory pathway (292.1 +/- 31.9 vs 299 +/- 58.1 ms, p less than .5) and the shortest cycle length with 1:1 conduction over the accessory pathway (306.7 +/- 75 vs 289.1 +/- 77.5 ms, p less than .5) similarly did not differ. We conclude that syncope occurs in approximately 20% of patients with the Wolff-Parkinson-White syndrome referred for assessment of tachycardia. Patients with syncope do not have distinct clinical features or a more malignant electrophysiologic profile, suggesting that other extracardiac factors may play an important role in the genesis of syncope in this group. PMID:6204291

  1. Photoinduced tellurium precipitation in CdTe

    NASA Astrophysics Data System (ADS)

    Sugai, Shunji

    1991-06-01

    Tellurium precipitation in CdTe is found to be induced by photoirradiation with energy higher than the energy gap at 240 W/sq cm. It is suggested that this photoinduced precipitation is related with the strong electron-phonon interactions, possibly self-trapped excitons. This irreducible tellurium precipitation may cause a serious problem for the life of semiconductor devices.

  2. Programmed Rearrangement in Ciliates: Paramecium.

    PubMed

    Betermier, Mireille; Duharcourt, Sandra

    2014-12-01

    Programmed genome rearrangements in the ciliate Paramecium provide a nice illustration of the impact of transposons on genome evolution and plasticity. During the sexual cycle, development of the somatic macronucleus involves elimination of ∼30% of the germline genome, including repeated DNA (e.g., transposons) and ∼45,000 single-copy internal eliminated sequences (IES). IES excision is a precise cut-and-close process, in which double-stranded DNA cleavage at IES ends depends on PiggyMac, a domesticated piggyBac transposase. Genome-wide analysis has revealed that at least a fraction of IESs originate from Tc/mariner transposons unrelated to piggyBac. Moreover, genomic sequences with no transposon origin, such as gene promoters, can be excised reproducibly as IESs, indicating that genome rearrangements contribute to the control of gene expression. How the system has evolved to allow elimination of DNA sequences with no recognizable conserved motif has been the subject of extensive research during the past two decades. Increasing evidence has accumulated for the participation of noncoding RNAs in epigenetic control of elimination for a subset of IESs, and in trans-generational inheritance of alternative rearrangement patterns. This chapter summarizes our current knowledge of the structure of the germline and somatic genomes for the model species Paramecium tetraurelia, and describes the DNA cleavage and repair factors that constitute the IES excision machinery. We present an overview of the role of specialized RNA interference machineries and their associated noncoding RNAs in the control of DNA elimination. Finally, we discuss how RNA-dependent modification and/or remodeling of chromatin may guide PiggyMac to its cognate cleavage sites. PMID:26104450

  3. Transposable elements as catalysts for chromosome rearrangements.

    PubMed

    Zhang, Jianbo; Yu, Chuanhe; Krishnaswamy, Lakshminarasimhan; Peterson, Thomas

    2011-01-01

    Barbara McClintock first showed that transposable elements in maize can induce major chromosomal rearrangements, including duplications, deletions, inversions, and translocations. More recently, researchers have made significant progress in elucidating the mechanisms by which transposons can induce genome rearrangements. For the Ac/Ds transposable element system, rearrangements are generated when the termini of different elements are used as substrates for transposition. The resulting alternative transposition reaction directly generates a variety of rearrangements. The size and type of rearrangements produced depend on the location and orientation of transposon insertion. A single locus containing a pair of alternative transposition-competent elements can produce a virtually unlimited number of genome rearrangements. With a basic understanding of the mechanisms involved, researchers are beginning to utilize both naturally occurring and in vitro-generated configurations of transposable elements in order to manipulate chromosome structure. PMID:21181539

  4. Extracorporeal life support for cardiac arrest in a 13-year-old girl caused by Wolff-Parkinson-White syndrome.

    PubMed

    Song, Kyoung Hwan; Lee, Byung Kook; Jeung, Kyung Woon; Lee, Dong Hun

    2015-10-01

    Generally, Wolff-Parkinson-White (WPW) syndrome presents good prognosis. However, several case reports demonstrated malignant arrhythmia or sudden cardiac death as WPW syndrome's first presentation. Cardiopulmonary resuscitation using extracorporeal life support is a therapeutic option in refractory cardiac arrest. We present a WPW syndrome patient who had sudden cardiac arrest as the first presentation of the disease and treated it using extracorporeal life support with good neurologic outcome. PMID:26314214

  5. A rare manifestation of atrial fibrillation in the presence of Wolff-Parkinson-White syndrome: tachycardia-induced cardiomyopathy.

    PubMed

    Değirmencioğu, Aleks; Karakuş, Gültekin; Baysal, Erkan; Zencirci, Ertuğrul; Çakmak, Nazmiye

    2014-03-01

    We report a 68-year-old man who presented with heart failure and atrial fibrillation (AF) with rapid ventricular response and wide QRS complexes. Tachycardia-induced cardiomyopathy (TIC) due to persistent AF developing on the basis of Wolff-Parkinson-White (WPW) syndrome was considered. Signs and symptoms of heart failure improved with restoration of sinus rhythm. This case suggested that persistent AF in a patient with WPW syndrome is one of the rare causes of TIC. PMID:24643151

  6. Regulation of immunoglobulin gene rearrangement and expression.

    PubMed

    Taussig, M J; Sims, M J; Krawinkel, U

    1989-05-01

    The molecular genetic events leading to Ig expression and their control formed the topic of a recent EMBO workshop. This report by Michael Taussig, Martin Sims and Ulrich Krawinkel discusses contributions dealing with genes expressed in early pre-B cells, the mechanism of rearrangement, aberrant rearrangements seen in B cells of SCID mice, the feedback control of rearrangement as studied in transgenic mice, the control of Ig expression at the transcriptional and post-transcriptional levels, and class switching. PMID:2787158

  7. Synthesis of a tricyclic lactam via Beckmann rearrangement and ring-rearrangement metathesis as key steps

    PubMed Central

    Ravikumar, Ongolu; Majhi, Jadab

    2015-01-01

    Summary A tricyclic lactam is reported in a four step synthesis sequence via Beckmann rearrangement and ring-rearrangement metathesis as key steps. Here, we used a simple starting material such as dicyclopentadiene. PMID:26425207

  8. Structural studies of photoinduced intramolecular electron transfer in cyclopentadienylnickelnitrosyl

    SciTech Connect

    Chen, L.X.; Bowman, M.K.; Wang, Zhiyu; Norris, J.R. |; Montano, P.A. |

    1994-03-01

    A structural study based on EXAFS, FTIR, and optical absorption spectroscopies has been conducted on a photogenerated, metastable state of cyclopentadienylnickelnitrosyl (CpNiNO) produced by a reversible photochemical reaction. The photogenerated, metastable state with distinctively different EXAFS, IR, and optical absorption spectra from those of the ground state molecules was created by irradiating the sample with the 365 nm line of a mercury lamp at 20K . At the same temperature, the reverse reaction was induced by irradiation with the 313 nm line from the mercury lamp. Based on the analysis of the EXAFS data, the photogenerated, metastable state of CpNiNO has undergone considerable nuclear rearrangements compared to its ground state. The nuclear movement is characterized by a 0.12{angstrom} elongation of Ni-N bond and by a bending of Ni-N-O. A shift of the N-O stretching frequency from 1824 to 1387 cm{sup {minus}1} was observed in the photoinduced reaction with 365 nm light, implying that a NO{sup {minus}} like species results from intramolecular electron transfer from Ni to NO. The changes in the absorption spectra for the same reaction showed reduced absorption of the 385 nm band and a newly generated broad band near IR region. Temperature dependence of the Debye-Waller factor of CpNiNO was in good agreement with the diatomic harmonic oscillator for the Ni-N bond, but deviated for the Ni-O and the Ni-C bonds. Based on the structures obtained from EXAFS, ZINDO calculations for both the ground state and the photogenerated, metastable state of CpNiNO reproduced the general features of the observed absorption spectra and qualitatively explained the wavelength dependence of the reaction. The calculated partial charges on each atom in the ground state and the photogenerated, metastable state of CpNiNO are consistent with intramolecular electron transfer upon photoexcitation by 365 nm light.

  9. Photoinduced mass transport in azo compounds

    NASA Astrophysics Data System (ADS)

    Klismeta, K.; Teteris, J.; Aleksejeva, J.

    2013-12-01

    The photoinduced changes of optical properties in azobenzene containing compound thin films were studied under influence of polarized and non-polarized 532 nm laser light. Under influence of light azo compounds experience trans-cis isomerisation process, that can be observed in the absorbance spectrum of the sample. If the light is linearly polarized, molecules align perpendicularly to the electric field vector and as a result photoinduced dichroism and birefringence is obtained. If a known lateral polarization modulation of the light beam is present, mass transport of the azobenzene containing compound occurs. By measuring the surface relief with a profilometer the direction of mass transport can be determined. The studies of this work show that direct holographic recording of surface relief gratings can be used in optoelectronics, telecommunications and data storage.

  10. Photoinduced Anomalous Hall Effects in Weyl Semimetals

    NASA Astrophysics Data System (ADS)

    Chan, Ching-Kit; Lee, Patrick A.; Burch, Kenneth S.; Han, Jung Hoon; Ran, Ying

    We examine theoretically the interplay between chiral photons and chiral electrons in Weyl semimetals. Owing to its monopole nature, a three-dimensional Weyl node is topologically-robust against a circularly polarized light. A driven Weyl system exhibits node shifts in the momentum space, in sharp contrast to the gap opening in a driven two-dimensional Dirac system. We show that the node shift leads to a change of the Chern vector which gives arise to a net photoinduced anomalous Hall conductivity, in the plane perpendicular to the light propagation. We shall describe the basic idea behind this generic photoinduced Hall effect, illustrate it with a concrete microscope model, and estimate its feasibility based on current optical experimental techniques.

  11. Fractionation, rearrangement and subgenome dominance

    PubMed Central

    Sankoff, David; Zheng, Chunfang

    2012-01-01

    Motivation: Fractionation is arguably the greatest cause of gene order disruption following whole genome duplication, causing severe biases in chromosome rearrangement-based estimates of evolutionary divergence. Results: We show how to correct for this bias almost entirely by means of a ‘consolidation’ algorithm for detecting and suitably transforming identifiable regions of fractionation. We characterize the process of fractionation and the performance of the algorithm through realistic simulations. We apply our method to a number of core eudicot genomes, we and by studying the fractionation regions detected, are able to address topical issues in polyploid evolution. Availability and implementation: Code for the consolidation algorithm, and sample data, is available at: http://137.122.149.195/Software/Fractionation/fractionation.html Contact: sankoff@uottawa.ca PMID:22962459

  12. Interpolation schemes for peptide rearrangements

    NASA Astrophysics Data System (ADS)

    Bauer, Marianne S.; Strodel, Birgit; Fejer, Szilard N.; Koslover, Elena F.; Wales, David J.

    2010-02-01

    A variety of methods (in total seven) comprising different combinations of internal and Cartesian coordinates are tested for interpolation and alignment in connection attempts for polypeptide rearrangements. We consider Cartesian coordinates, the internal coordinates used in CHARMM, and natural internal coordinates, each of which has been interfaced to the OPTIM code and compared with the corresponding results for united-atom force fields. We show that aligning the methylene hydrogens to preserve the sign of a local dihedral angle, rather than minimizing a distance metric, provides significant improvements with respect to connection times and failures. We also demonstrate the superiority of natural coordinate methods in conjunction with internal alignment. Checking the potential energy of the interpolated structures can act as a criterion for the choice of the interpolation coordinate system, which reduces failures and connection times significantly.

  13. Interpolation schemes for peptide rearrangements.

    PubMed

    Bauer, Marianne S; Strodel, Birgit; Fejer, Szilard N; Koslover, Elena F; Wales, David J

    2010-02-01

    A variety of methods (in total seven) comprising different combinations of internal and Cartesian coordinates are tested for interpolation and alignment in connection attempts for polypeptide rearrangements. We consider Cartesian coordinates, the internal coordinates used in CHARMM, and natural internal coordinates, each of which has been interfaced to the OPTIM code and compared with the corresponding results for united-atom force fields. We show that aligning the methylene hydrogens to preserve the sign of a local dihedral angle, rather than minimizing a distance metric, provides significant improvements with respect to connection times and failures. We also demonstrate the superiority of natural coordinate methods in conjunction with internal alignment. Checking the potential energy of the interpolated structures can act as a criterion for the choice of the interpolation coordinate system, which reduces failures and connection times significantly. PMID:20136299

  14. Rearrangement of sulfonamidyl radicals with hydrogen migration

    SciTech Connect

    Troyanskii, E.I.; Lazareva, M.I.; Nikishin, G.I.

    1987-01-20

    One-step outlying oxidative chlorination of alkanesulfonamides by the action of the Na/sub 2/S/sub 2/O/sub 8/-CuCl/sub 2/ system via intermediate sulfonamidyl radicals gives 3- and 4-chloroalkanesulfonamides. Rearrangements of sulfonamidyl radicals with H atom migration from the sulfonyl segment predominates over rearrangement with H atom migration from the amide segment.

  15. Inspiring Examples in Rearrangements of Infinite Products

    ERIC Educational Resources Information Center

    Ramasinghe, W.

    2007-01-01

    It is well known that simple examples are really encouraging in the understanding of rearrangements of infinite series. In this paper a similar role is played by simple examples in the case of infinite products. Iterated products of double products seem to have a similar spirit of rearrangements of products, although they are not the same.…

  16. Thyroid storm in a patient with Wolff-Parkinson-White syndrome.

    PubMed

    Naqvi, Syed Yaseen; Luebbert, Jeffrey J; Rosen, Stephen G

    2015-01-01

    A 44-year-old woman with no medical history presented to the emergency department with a 2 h history of sudden onset chest pressure, palpitations, diaphoresis and shortness of breath. She reported a 90-pound unintentional weight loss, increased appetite, irritability, night sweats and palpitations for 2 months. Physical examination revealed a heart rate (HR) of 269 bpm and a blood pressure of 116/94 mm Hg. Her ECG revealed a wide-complex tachycardia with right bundle branch morphology and an HR of 265 bpm. Intravenous adenosine was administered with resolution of the arrhythmia and symptoms. Her subsequent ECG revealed sinus tachycardia with δ waves, which was consistent with Wolff-Parkinson-White (WPW) syndrome. Laboratory findings confirmed thyroid storm and treatment began with intravenous hydrocortisone, methimazole, metoprolol, amiodarone and iodine drops. Graves' disease was confirmed based on the presence of serum thyroid-stimulating hormone receptor antibody. The patient underwent successful WPW accessory tract ablation 6 weeks after initial presentation. PMID:26670895

  17. Exercise testing in children with Wolff-Parkinson-White syndrome: what is its value?

    PubMed

    Dalili, M; Vahidshahi, K; Aarabi-Moghaddam, M Y; Rao, J Y; Brugada, P

    2014-10-01

    This study was conducted to evaluate the accuracy of exercise testing for predicting accessory pathway characteristics in children with Wolff-Parkinson-White (WPW) syndrome. The study enrolled 37 children with WPW syndrome and candidates for invasive electrophysiologic study (EPS). Exercise testing was performed for all the study participants before the invasive study. Data from the invasive EPS were compared with findings from the exercise testing. The sudden disappearance of the delta (Δ) wave was seen in 10 cases (27 %). No significant correlation was found between the Δ wave disappearance and the antegrade effective refractory period of the accessory pathway (AERP-AP) or the shortest pre-excited RR interval (SPERRI). The sensitivity, specificity, and positive and negative predictive values of Δ wave disappearance, based on AERP-AP as gold standard, were respectively 29.4, 80, 71.4, and 40 %. The corresponding values with SPERRI as the gold standard were respectively 23.8, 71.4, 71.4 and 23.8 %. Exercise testing has a medium to low rate of accuracy in detecting low-risk WPW syndrome patients in the pediatric age group. PMID:24728424

  18. Exercise testing in Wolff-Parkinson-White syndrome: case report with ECG and literature review.

    PubMed

    Jezior, Matthew R; Kent, Steven M; Atwood, J Edwin

    2005-04-01

    ECG changes during exercise stress testing, such as false-positive ST-segment depression and disappearance of the delta wave, are reported in patients with the Wolff-Parkinson-White (WPW) pattern. We present a case of exercise testing in a 53-year-old man with WPW syndrome with ischemic-appearing ECG changes and normal nuclear stress perfusion study findings who was thought to be at clinically low risk for having significant coronary disease. A literature review is discussed. Although ST-segment depression typical for ischemia occurs in half of the patients in whom WPW syndrome is reported, exercise testing is still an important tool in their evaluation. Data other than ECG response can be interpreted in the context of clinical history and physical examination findings to stratify the risk of coronary disease. Complete and sudden disappearance of the delta wave has been seen during exercise in 20% of patients with WPW syndrome and can identify those who are at low risk for sudden arrhythmic death. PMID:15821231

  19. [Prognostic significance of syncope in patients with Wolff-Parkinson-White syndrome].

    PubMed

    Auricchio, A; Klein, H; Trappe, H J; Troester, J

    1990-12-01

    The prognostic value of syncope in symptomatic patients with Wolff-Parkinson-White syndrome (WPW) is unknown. Therefore, in order to evaluate the sensibility, specificity, positive and negative predictive value of syncope and compare those values with the one obtained for the shortest RR interval (less than or equal to 250 msec) as well as for the anterograde refractory period of the accessory pathway (less than 270 msec), we reviewed the clinical and electrophysiological data of 158 symptomatic patients with WPW. Fourty-eight patients (30%) reported at least one episode of syncope, and 24 out of 158 patients experienced an aborted sudden death, probably due to rapid conduction via the accessory pathway during atrial fibrillation. Syncope has poor sensibility but high specificity in recognizing an aborted sudden death. However, the syncope demonstrated it had a lower prognostic value when compared with other electrophysiological parameters in correctly identifying patients with a history of ventricular tachycardia and/or fibrillation. In conclusion, the data of this study propose the symptom "syncope" as a frequent event in the history of symptomatic patients with WPW referred to electrophysiological study. Generally its presence does not correctly identify patients who experienced an aborted sudden death. Furthermore, its prognostic value is significantly lower than a shorter RR interval (less than or equal to 250 msec) during atrial fibrillation and an anterograde effective refractory period less than 270 msec. PMID:2083811

  20. Should radiofrequency current ablation be performed in asymptomatic patients with the Wolff-Parkinson-White syndrome?

    PubMed

    Steinbeck, G

    1993-03-01

    The exiting new method of ablation of accessory pathways using radiofrequency current applied by catheters will dramatically change our therapeutic decisions in these patients in the near future. This brief survey reviews the existing literature about the risk of the disease as well as of the procedure of catheter ablation. From these data, the risk of sudden death appears to be extremely low in asymptomatic Wolff-Parkinson-White (WPW) individuals. Side effects of catheter ablation may result from the invasive procedure as well as from radiation exposure (the latter to the patient as well as to operating physicians). While the complication rate in experienced centers is extremely low, a multicenter registry of the success and complication rate is urgently needed in view of the many centers starting with catheter ablation. Based on a subjective benefit-to-risk analysis, asymptomatic WPW individuals should be offered catheter ablation only under special circumstances (high risk profession, athletes, family history of sudden death). On the other hand, catheter ablation need not be and should not be considered generally in asymptomatic individuals with WPW pattern. Finally, this author cannot imagine that the energy, time, and money spent for mass screening and eventual catheter ablation of asymptomatic WPW individuals with its attending risks can be outweighed by the potential benefits for these asymptomatic individuals. PMID:7681970

  1. Catheter ablation of Wolff-Parkinson-White syndrome associated with congenital absence of inferior vena cava.

    PubMed

    Inama, G; Vergara, G; Gramegna, L; Rillo, M; Fuochi, C; Furlanello, F

    1998-09-01

    In the present report we describe a patient (a 36-year-old woman with 15 year history of supraventricular tachyarrhythmias) with congenital absence of inferior vena cava (IVC) revealed during radiofrequency (RF) catheter ablation procedure for right postero-septal Wolff-Parkinson-White syndrome (WPW). For the absence of IVC, the ablation procedure was more difficult, because we had to perform the ablation with the catheters (the ablator catheter and the coronary sinus catheter) introduced both through the superior vena cava. The application of RF energy (35 Watt for 60 seconds) at successful site abolished accessory pathway conduction. The following day was performed the venous angiography, showing the absence of the IVC and a venous return via paravertebral venous plexus to the azygous vein and superior vena cava into the right atrium. Computer tomography confirmed the absence of the IVC with azygous continuation. The drainage via the azygous system modified the radiological image on chest roentgenogram of the right mediastinal silhouette. During cardiogenesis fusion of the IVC and organisation of the heart occur between the 33rd to 40th embryonic days. It is therefore possible that some unknown teratogenic mechanism at this critical period might have caused, in the patient, both the developmental arrest of IVC and failure of regression of atrio-ventricular anatomical and electrical continuity in the right postero-septal region. PMID:9870026

  2. Trabecular bone of precocials at birth; Are they prepared to run for the wolf(f)?

    PubMed

    Gorissen, Ben M C; Wolschrijn, Claudia F; van Vilsteren, Anouk A M; van Rietbergen, Bert; van Weeren, P René

    2016-07-01

    Bone is a dynamic tissue adapting to loading according to "Wolff's law of bone adaptation." During very early life, however, such a mechanism may not be adequate enough to adapt to the dramatic change in environmental challenges in precocial species. Their neonates are required to stand and walk within hours after birth, in contrast to altricial animals that have much more time to adapt from the intrauterine environment to the outside world. In this study, trabecular bone parameters of the talus and sagittal ridge of the tibia from stillborn but full-term precocials (calves and foals) were analyzed by micro-CT imaging in order to identify possible anticipatory mechanisms to loading. Calculated average bone volume fraction in the Shetland pony (49-74%) was significantly higher compared to Warmblood foals (28-51%). Bovine trabecular bone was characterized by a low average bone volume fraction (22-28%), however, more directional anisotropy was found. It is concluded that anticipatory strategies in skeletal development exist in precocial species, which differ per species and are most likely related to anatomical differences in joint geometry and related loading patterns. The underlying regulatory mechanisms are still unknown, but they may be based on a genetic blueprint for the development of bone. More knowledge, both about a possible blueprint and its regulation, will be helpful in understanding developmental bone and joint diseases. J. Morphol. 277:948-956, 2016. © 2016 Wiley Periodicals, Inc. PMID:27098190

  3. The use of sugammadex in a pregnant patient with Wolff-Parkinson-White syndrome.

    PubMed

    Sengul, Turker; Saracoglu, Ayten; Sener, Sibel; Bezen, Olgac

    2016-09-01

    Wolff-Parkinson-White (WPW) syndrome is a rare pre-excitation syndrome which develops when atrioventricular conduction occurs through a pathologic accessory pathway known as the bundle of Kent instead of atrioventricular node, hence resulting in tachycardia. Patients with WPW syndrome may experience various symptoms arising from mild-to-moderate chest disease, palpitations, hypotension, and severe cardiopulmonary dysfunction. These patients are most often symptomatic because of cardiac arrhythmias. In this case report, we present an uneventful anesthetic management of a pregnant patient with WPW syndrome undergoing cesarean delivery. A 23-year-old American Society of Anesthesiologists class 2 pregnant patient was diagnosed with WPW syndrome. Her preoperative 12-lead electrocardiogram showed a sinus rhythm at 82 beats per minute, a delta wave, and a short PR interval. After an uneventful surgery, sugammadex 2mg/kg was administered as a reversal agent instead of neostigmine. Then she was discharged to her obstetrics service. Serious hemodynamic disorders may occur in patients with WPW syndrome due to development of fatal arrhythmias. Neostigmine used as a reversal agent in general anesthesia can trigger such fatal arrhythmias by leading changes in cardiac conduction. We believe that sugammadex, which is safely used in many areas in the scope of clinical practice, can be also used for patients diagnosed with WPW syndrome. PMID:27555124

  4. Exome analysis of a family with Wolff-Parkinson-White syndrome identifies a novel disease locus.

    PubMed

    Bowles, Neil E; Jou, Chuanchau J; Arrington, Cammon B; Kennedy, Brett J; Earl, Aubree; Matsunami, Norisada; Meyers, Lindsay L; Etheridge, Susan P; Saarel, Elizabeth V; Bleyl, Steven B; Yost, H Joseph; Yandell, Mark; Leppert, Mark F; Tristani-Firouzi, Martin; Gruber, Peter J

    2015-12-01

    Wolff-Parkinson-White (WPW) syndrome is a common cause of supraventricular tachycardia that carries a risk of sudden cardiac death. To date, mutations in only one gene, PRKAG2, which encodes the 5'-AMP-activated protein kinase subunit γ-2, have been identified as causative for WPW. DNA samples from five members of a family with WPW were analyzed by exome sequencing. We applied recently designed prioritization strategies (VAAST/pedigree VAAST) coupled with an ontology-based algorithm (Phevor) that reduced the number of potentially damaging variants to 10: a variant in KCNE2 previously associated with Long QT syndrome was also identified. Of these 11 variants, only MYH6 p.E1885K segregated with the WPW phenotype in all affected individuals and was absent in 10 unaffected family members. This variant was predicted to be damaging by in silico methods and is not present in the 1,000 genome and NHLBI exome sequencing project databases. Screening of a replication cohort of 47 unrelated WPW patients did not identify other likely causative variants in PRKAG2 or MYH6. MYH6 variants have been identified in patients with atrial septal defects, cardiomyopathies, and sick sinus syndrome. Our data highlight the pleiotropic nature of phenotypes associated with defects in this gene. PMID:26284702

  5. The complete chloroplast genome sequence of Ledebouriella seseloides (Hoffm.) H. Wolff.

    PubMed

    Lee, Hyun Oh; Kim, Kyunghee; Lee, Sang-Choon; Lee, Junki; Lee, Jonghoon; Kim, Soonok; Yang, Tae-Jin

    2016-09-01

    Ledebouriella seseloides (Hoffm.) H.Wolff is a traditional medicinal herb belonging to Apiaceae family, whose dried roots and rhizomes have been used as traditional medicine in East Asian countries. The complete chloroplast genome of L. seseloides was obtained by de novo assembly using the small amount of whole genome sequencing data. The chloroplast genome of L. seseloides was 147 880 bp in length, which consisted of large single copy region (93 222 bp), small single copy region (17 324 bp), and a pair of inverted repeat regions (18 667 bp). The overall GC contents of the chloroplast genome were 37.5%. A total of 113 genes were annotated, which included 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. Phylogenetic analysis with the reported chloroplast genomes revealed that L. seseloides is most closely related to Petroselinum crispum (parsley), an herb widely used in cooking. PMID:26218226

  6. Lack of feedback inhibition of V kappa gene rearrangement by productively rearranged alleles.

    PubMed

    Harada, K; Yamagishi, H

    1991-02-01

    Circular DNAs excised by immunoglobulin kappa chain gene rearrangements were cloned and characterized. 16 of 17 clones examined were double recombination products containing a V kappa-J kappa rearrangement (coding joint) as well as the reciprocal element (signal joint) of another V kappa-J kappa rearrangement. These products suggested multiple recombination, primary inversion, and secondary excision. In primary events, 5 of 16 translational reading frames were in-phase. Thus, V kappa gene rearrangement may not be inhibited by the presence of a productively rearranged allele. An unusually large trinucleotide (P) insertion forming a palindrome of 12 nucleotides was also observed in one of the coding joints. PMID:1988542

  7. Rearrangements of organic peroxides and related processes

    PubMed Central

    Yaremenko, Ivan A; Vil’, Vera A; Demchuk, Dmitry V

    2016-01-01

    Summary This review is the first to collate and summarize main data on named and unnamed rearrangement reactions of peroxides. It should be noted, that in the chemistry of peroxides two types of processes are considered under the term rearrangements. These are conventional rearrangements occurring with the retention of the molecular weight and transformations of one of the peroxide moieties after O–O-bond cleavage. Detailed information about the Baeyer−Villiger, Criegee, Hock, Kornblum−DeLaMare, Dakin, Elbs, Schenck, Smith, Wieland, and Story reactions is given. Unnamed rearrangements of organic peroxides and related processes are also analyzed. The rearrangements and related processes of important natural and synthetic peroxides are discussed separately. PMID:27559418

  8. Kinetics of a photoinduced NH tautomerism of free-base porphyrins in crystalline matrices at low temperatures: Computer simulations and experiment

    NASA Astrophysics Data System (ADS)

    Stanishevsky, I. V.; Solovyov, K. N.

    2004-03-01

    Photoinduced NH tautomerism, along with the reaction pathways of phototautomerization in tetrabenzoporphin and porphin free bases in n-octane polycrystalline matrices at 77 K, is studied by simulation of kinetic processes and their experimental observation. The simulation of the processes is performed by the numerical solution of the system of kinetic equations describing the populations of electronic levels and transitions between them. Kinetic dependences are obtained by measuring the perturbation of stationary fluorescence of one component of the 0-0 doublet origin upon pulsed selective photoexcitation of the other component. For two tautomeric forms related by the reversibility of the photochemical reaction, under the assumption of synchronism of the NH rearrangement, (i) analytical solutions governing the reaction rate are found, (ii) a method of measuring the rate constants of the proton rearrangement is suggested and the constants themselves are estimated, and (iii) direct evidence of the participation of T 1 levels in the photochemical reaction is obtained. With the aid of numerical simulations, the specific features of kinetic manifestation of an asynchronous mechanism of the photoinduced NH rearrangement are studied.

  9. Chromosome rearrangements and transposable elements.

    PubMed

    Lonnig, Wolf-Ekkehard; Saedler, Heinz

    2002-01-01

    There has been limited corroboration to date for McClintock's vision of gene regulation by transposable elements (TEs), although her proposition on the origin of species by TE-induced complex chromosome reorganizations in combination with gene mutations, i.e., the involvement of both factors in relatively sudden formations of species in many plant and animal genera, has been more promising. Moreover, resolution is in sight for several seemingly contradictory phenomena such as the endless reshuffling of chromosome structures and gene sequences versus synteny and the constancy of living fossils (or stasis in general). Recent wide-ranging investigations have confirmed and enlarged the number of earlier cases of TE target site selection (hot spots for TE integration), implying preestablished rather than accidental chromosome rearrangements for nonhomologous recombination of host DNA. The possibility of a partly predetermined generation of biodiversity and new species is discussed. The views of several leading transposon experts on the rather abrupt origin of new species have not been synthesized into the macroevolutionary theory of the punctuated equilibrium school of paleontology inferred from thoroughly consistent features of the fossil record. PMID:12429698

  10. The speed of topological rearrangements in foam

    NASA Astrophysics Data System (ADS)

    Thoroddsen, S. T.; Tan, E.

    1999-11-01

    Coarsening of dry foam is characterized by a slow diffusion of gas across the fluid films separating adjacent foam cells, punctuated by rapid topological rearrangements of the polyhedral network. In this work we measure and model the speed of a typical rearrangement event, which has been reproduced on an adjustable metal frame. The interstitial liquid viscosity is varied by adding glycerin to the water/soap solution and is found to reduce the speed only at high viscosities. Marangoni effects play on the other hand a pivotal role for the lowest soap concentrations, greatly slowing down the rearrangements.

  11. Untangling Membrane Rearrangement in the Nidovirales

    PubMed Central

    Angelini, Megan Mary; Neuman, Benjamin William

    2014-01-01

    All known positive sense single-stranded RNA viruses induce host cell membrane rearrangement for purposes of aiding viral genome replication and transcription. Members of the Nidovirales order are no exception, inducing intricate regions of double membrane vesicles and convoluted membranes crucial for the production of viral progeny. Although these structures have been well studied for some members of this order, much remains unclear regarding the biogenesis of these rearranged membranes. Here, we discuss what is known about these structures and their formation, compare some of the driving viral proteins behind this process across the nidovirus order, and examine possible routes of mechanism by which membrane rearrangement may occur. PMID:24410069

  12. Photoinduced spinodal decomposition in stratifying solutions

    NASA Astrophysics Data System (ADS)

    Bunkin, F. V.; Podgaetskii, V. I.; Semin, V. N.

    1988-01-01

    The effect of photoinduced spinodal decomposition in stratifying solutions is examined with particular reference to experimental results obtained for an aqueous solution of butyl Cellosolve of critical concentration (30.14 percent by mass). At the late stages of spinodal decomposition, the coalescence of similar microheterophase inhomogeneities leads to the formation of small-scale (up to 5 microns) grains of each of the phases, which are then grouped into larger-scale (up to 100 microns) segregations. Such multilevel self-organization of the stratifying phases leads to the formation of a granular-cellular structure. This effect can be used for the quick interruption of chemical reactions in a stratifying solution.

  13. [Should the Isuprel test be performed systematically in Wolff-Parkinson-White syndrome?].

    PubMed

    Brembilla-Perrot, B; Terrier de la Chaise, A; Marçon, F; Cherrier, F; Pernot, C

    1988-10-01

    The isoprenaline (Is) test was designed by Wellens et al. in 1982 to evaluate the effect of catecholamines on the effective refractory period (ERP) of Kent's bundle (K). The purpose of our study was to assess the value of this test in the prognosis of Wolff-Parkinson-White syndrome (WPW), to define its criteria of severity and to determine the usefulness of the test. Out of 33 patients with WPW syndrome, 10 (group I) had a clinical history of severe arrhythmia and 23 (group II) were asymptomatic or had paroxysmal nodal tachycardia. The prognosis of WPW syndrome was evaluated by measuring Kent's bundle ERP under coupled atrial stimulation (S1 S2) and the shortest cycle conducted by K during induced atrial fibrillation (AF) and atrial pacing (AP) both in the basal state (B) and under a 20-30 micrograms Is infusion. (table; see text). Analysis of the results showed constant shortening of ERP in group I and reproduction of the clinical tachycardia in 6 cases. In group II patients isoprenaline unmasked the WPW syndrome in 3 cases and reproduced the clinical tachycardia in 5 cases. The ERP of Kent's bundle evaluated by S1 S2 became smaller or equal to 220 ms in 70 p. 100 of the cases, and this shortening was not specific. The shortest cycle in AF or AP became inferior of equal to 220 ms in only 6 cases, the history being concordant with clinical findings in 4 of them. Altogether, the most reliable and simplest way of evaluating the severity of WPW syndrome is the highest frequency conducted by Kent's bundle in atrial pacing during the Is test which should be performed in all patients in view of its specificity, simplicity and safety. PMID:3146959

  14. [Syncope in patients with Wolff-Parkinson-White syndrome: clinical data, electrophysiologic substrate and prognostic value].

    PubMed

    Auricchio, A; Klein, H; Trappe, H J; Becht, I; Wenzlaff, P; Iacono, A

    1989-10-01

    Syncope in Wolff-Parkinson-White (WPW) patients might be considered a premonitory event heralding the future development of sudden death. Therefore, we reviewed the clinical and electrophysiologic data of 91 WPW patients referred for invasive evaluation of known arrhythmias, in order to assess the incidence and clinical relevance of syncope. Thirty-four patients (37%, Group I) reported the occurrence of 1 or more syncopal episodes, while 57 patients (63%, Group II) had no syncope. These 2 groups did not differ significantly with regard to age, sex, incidence and characteristics of arrhythmias, clinical history and frequency of arrhythmic events, presence of associated cardiac diseases. Eleven patients in Group I and 9 in Group II were resuscitated from a cardiac arrest. The sensitivity (40%), the specificity (64%) as well as the positive predictive value (32%) and the negative predictive value (71%) of syncope vs a cardiac arrest were not significant. There were no statistical differences in the effective refractory period of the right atrium, atrioventricular node, accessory pathway and right ventricle between the 2 groups. Furthermore, no differences were noted in the cycle length of tachycardia (327 +/- 60 ms in Group I and 335 +/- 46 ms in Group II) and in the minimum RR interval during atrial fibrillation (248 +/- 49 ms and 244 +/- 43 ms, in Group I and II, respectively) as well as in the number of patients who had a minimum RR interval during atrial fibrillation less than or equal to 250 ms (15 patients--65%--in Group I and 21 patients--62%--in Group II).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2605574

  15. [Atrial fibrillation in Wolff-Parkinson-White syndrome. Development and therapy].

    PubMed

    Duckeck, W; Kuck, K H

    1993-02-01

    In patients with Wolff-Parkinson-White syndrome the accessory pathway may participate in various tachyarrhythmias thereby influencing symptoms and prognosis. Atrial fibrillation occurs in 10 to 32% of patients and may have life-threatening consequences by precipitating ventricular fibrillation in patients with rapid conduction due to an accessory pathway with short anterograde refractory period (< 250 ms). Pathogenesis of atrial fibrillation in the WPW syndrome and therapeutic options are reviewed in this presentation. Spontaneous degeneration of atrioventricular reentrant tachycardia has been reported to represent the most frequent mode of initiation of atrial fibrillation during electrophysiologic study (up to 64% of episodes). Hemodynamic changes during tachycardia may lead to increased sympathetic tone, hypoxemia or increased tension of the atrial wall, thus, triggering atrial fibrillation. Induction of reentrant tachycardia during electrophysiologic study also has shown to be strongly correlated to its clinical prevalence and is inducible in up to 77% of patients with atrial fibrillation. The pathogenesis and high incidence of atrial fibrillation in patients with WPW syndrome is related to presence and functional properties of the accessory pathway. After surgical excision or catheter ablation more than 90% of patients are free of this arrhythmia. Anterograde conduction properties of the pathway appear to be more important than retrograde properties. High incidence of atrial fibrillation is related to short anterograde refractory periods, and of note, this arrhythmia is rare (3%) in patients with concealed pathways. With intracardiac recordings, Jackman et al. could demonstrate atrial fibrillation due to micro-reentry originating in accessory pathway networks.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8454253

  16. Electrophysiology testing and catheter ablation are helpful when evaluating asymptomatic patients with Wolff-Parkinson-White pattern: the con perspective.

    PubMed

    Skanes, Allan C; Obeyesekere, Manoj; Klein, George J

    2015-09-01

    The association between asymptomatic Wolff-Parkinson-White (WPW) syndrome and sudden cardiac death (SCD) has been well documented. The inherent properties of the accessory pathway determine the risk of SCD in WPW, and catheter ablation essentially eliminates this risk. An approach to WPW syndrome is needed that incorporates the patient's individualized considerations into the decision making. Patients must understand that there is a trade-off of a small immediate risk of an invasive approach for elimination of a small lifetime risk of the natural history of asymptomatic WPW. Clinicians can minimize the invasive risk by only performing ablation for patients with at-risk pathways. PMID:26304516

  17. Electrophysiology testing and catheter ablation are helpful when evaluating asymptomatic patients with Wolff-Parkinson-White pattern: the pro perspective.

    PubMed

    Pappone, Carlo; Santinelli, Vincenzo

    2015-09-01

    Important advances in the natural history and diagnosis of, and therapy for, asymptomatic Wolff-Parkinson-White (WPW) syndrome have been made in the last decade by our group. These data have necessitated revisiting current practice guidelines to decide on the optimal management of the asymptomatic WPW population. There has also been an emphasis on identifying initially asymptomatic individuals who are at risk by nationwide screening programs using the electrocardiogram for prophylactic catheter ablation to prevent the lifetime risk of sudden cardiac death, particularly in young asymptomatic people, because only a subgroup of them is at high risk, requiring early catheter ablation. PMID:26304515

  18. Ventricular fibrillation development following atrial fibrillation after the ingestion of sildenaphil in a patient with Wolff-Parkinson-White syndrome.

    PubMed

    Inci, Sinan; Izgu, Ibrahim; Aktas, Halil; Dogan, Pinar; Dogan, Ali

    2015-08-01

    Complications in the accessory pathway in Wolff-Parkinson-White (WPW) syndrome could cause different clinical conditions by inducing different arrhythmias. Atrial fibrillation (AF) is one of these arrhythmias and is important as it causes life-threatening arrhythmias. It is known that some drugs, underlying cardiac diseases, and the number of accessory pathways, cause a predisposition to this condition. In the current report, we presented a patient with WPW who was admitted to the emergency department with AF, wide QRS and a rapid ventricular response that progressed to ventricular fibrillation. PMID:26361569

  19. Ventricular fibrillation development following atrial fibrillation after the ingestion of sildenaphil in a patient with Wolff-Parkinson-White syndrome

    PubMed Central

    Inci, Sinan; Izgu, Ibrahim; Aktas, Halil; Dogan, Pinar; Dogan, Ali

    2015-01-01

    Summary Complications in the accessory pathway in Wolff-Parkinson-White (WPW) syndrome could cause different clinical conditions by inducing different arrhythmias. Atrial fibrillation (AF) is one of these arrhythmias and is important as it causes life-threatening arrhythmias. It is known that some drugs, underlying cardiac diseases, and the number of accessory pathways, cause a predisposition to this condition. In the current report, we presented a patient with WPW who was admitted to the emergency department with AF, wide QRS and a rapid ventricular response that progressed to ventricular fibrillation. PMID:26361569

  20. Association of a Wolff-Parkinson-White syndrome and a fistula from the coronary to the pulmonary artery.

    PubMed

    Fonteyne, W; Van Nooten, G; Jordaens, L

    1993-01-01

    We report the case history of a 52-year-old man with the Wolff-Parkinson-White syndrome and a fistula from the left anterior descending artery to the pulmonary artery. He had a left lateral bypass tract. To our knowledge, this is the first reported case of this association. Arterial malformations, along with vascular malformations of the coronary sinus, can be present in patients with a WPW syndrome. Coronary angiography with attention to the possible presence of arterial and venous malformations is indicated when atypical symptoms or signs are present in the WPW syndrome. PMID:8447186

  1. Spontaneous Transition of Double Tachycardias with Atrial Fusion in a Patient with Wolff-Parkinson-White Syndrome

    PubMed Central

    Kim, Dongmin

    2016-01-01

    Among patients with Wolff-Parkinson-White syndrome, atrioventricular reciprocating tachycardia (AVRT) and atrioventricular nodal reentrant tachycardia (AVNRT) can coexist in a single patient. Direct transition of both tachycardias is rare; however, it can occur after premature atrial or ventricular activity if the cycle lengths of the two tachycardias are similar. Furthermore, persistent atrial activation by an accessory pathway (AP) located outside of the AV node during ongoing AVNRT is also rare. This article describes a case of uncommon atrial activation by an AP during AVNRT and gradual transition of the two supraventricular tachycardias without any preceding atrial or ventricular activity in a patient with preexcitation syndrome. PMID:27482269

  2. Pd-catalyzed Semmler-Wolff reactions for the conversion of substituted cyclohexenone oximes to primary anilines.

    PubMed

    Hong, Wan Pyo; Iosub, Andrei V; Stahl, Shannon S

    2013-09-18

    Homogeneous Pd catalysts have been identified for the conversion of cyclohexenone and tetralone O-pivaloyl oximes to the corresponding primary anilines and 1-aminonaphthalenes. This method is inspired by the Semmler-Wolff reaction, a classic method that exhibits limited synthetic utility owing to its forcing conditions, narrow scope, and low product yields. The oxime N-O bond undergoes oxidative addition to Pd(0)(PCy3)2, and the product of this step has been characterized by X-ray crystallography and shown to undergo dehydrogenation to afford the aniline product. PMID:23987212

  3. The cytogenetics of mammalian autosomal rearrangements

    SciTech Connect

    Daniel, A. )

    1988-01-01

    This book is covered under the following topics: Ascertainment and risks of recombinant progeny; Infertility, gametic selection, and fetal loss; origin of chromosome rearrangements; and Some implications of chromosome breakpoints.

  4. Glycolytic regulation of cell rearrangement in angiogenesis

    PubMed Central

    Cruys, Bert; Wong, Brian W.; Kuchnio, Anna; Verdegem, Dries; Cantelmo, Anna Rita; Conradi, Lena-Christin; Vandekeere, Saar; Bouché, Ann; Cornelissen, Ivo; Vinckier, Stefan; Merks, Roeland M. H.; Dejana, Elisabetta; Gerhardt, Holger; Dewerchin, Mieke; Bentley, Katie; Carmeliet, Peter

    2016-01-01

    During vessel sprouting, endothelial cells (ECs) dynamically rearrange positions in the sprout to compete for the tip position. We recently identified a key role for the glycolytic activator PFKFB3 in vessel sprouting by regulating cytoskeleton remodelling, migration and tip cell competitiveness. It is, however, unknown how glycolysis regulates EC rearrangement during vessel sprouting. Here we report that computational simulations, validated by experimentation, predict that glycolytic production of ATP drives EC rearrangement by promoting filopodia formation and reducing intercellular adhesion. Notably, the simulations correctly predicted that blocking PFKFB3 normalizes the disturbed EC rearrangement in high VEGF conditions, as occurs during pathological angiogenesis. This interdisciplinary study integrates EC metabolism in vessel sprouting, yielding mechanistic insight in the control of vessel sprouting by glycolysis, and suggesting anti-glycolytic therapy for vessel normalization in cancer and non-malignant diseases. PMID:27436424

  5. Thermal rearrangement of tert-butylsulfinamide

    PubMed Central

    Gorentla, Laxminarasimhulu; Dubey, Pramod Kumar

    2011-01-01

    Summary tert-Butylsulfinamides are unstable above room temperature, and in chlorinated solvents they undergo rearrangement to form the more stable N-(tert-butylthio)-tert-butylsulfonamide. PMID:21286388

  6. Glycolytic regulation of cell rearrangement in angiogenesis.

    PubMed

    Cruys, Bert; Wong, Brian W; Kuchnio, Anna; Verdegem, Dries; Cantelmo, Anna Rita; Conradi, Lena-Christin; Vandekeere, Saar; Bouché, Ann; Cornelissen, Ivo; Vinckier, Stefan; Merks, Roeland M H; Dejana, Elisabetta; Gerhardt, Holger; Dewerchin, Mieke; Bentley, Katie; Carmeliet, Peter

    2016-01-01

    During vessel sprouting, endothelial cells (ECs) dynamically rearrange positions in the sprout to compete for the tip position. We recently identified a key role for the glycolytic activator PFKFB3 in vessel sprouting by regulating cytoskeleton remodelling, migration and tip cell competitiveness. It is, however, unknown how glycolysis regulates EC rearrangement during vessel sprouting. Here we report that computational simulations, validated by experimentation, predict that glycolytic production of ATP drives EC rearrangement by promoting filopodia formation and reducing intercellular adhesion. Notably, the simulations correctly predicted that blocking PFKFB3 normalizes the disturbed EC rearrangement in high VEGF conditions, as occurs during pathological angiogenesis. This interdisciplinary study integrates EC metabolism in vessel sprouting, yielding mechanistic insight in the control of vessel sprouting by glycolysis, and suggesting anti-glycolytic therapy for vessel normalization in cancer and non-malignant diseases. PMID:27436424

  7. Nanoscale chemical imaging by photoinduced force microscopy.

    PubMed

    Nowak, Derek; Morrison, William; Wickramasinghe, H Kumar; Jahng, Junghoon; Potma, Eric; Wan, Lei; Ruiz, Ricardo; Albrecht, Thomas R; Schmidt, Kristin; Frommer, Jane; Sanders, Daniel P; Park, Sung

    2016-03-01

    Correlating spatial chemical information with the morphology of closely packed nanostructures remains a challenge for the scientific community. For example, supramolecular self-assembly, which provides a powerful and low-cost way to create nanoscale patterns and engineered nanostructures, is not easily interrogated in real space via existing nondestructive techniques based on optics or electrons. A novel scanning probe technique called infrared photoinduced force microscopy (IR PiFM) directly measures the photoinduced polarizability of the sample in the near field by detecting the time-integrated force between the tip and the sample. By imaging at multiple IR wavelengths corresponding to absorption peaks of different chemical species, PiFM has demonstrated the ability to spatially map nm-scale patterns of the individual chemical components of two different types of self-assembled block copolymer films. With chemical-specific nanometer-scale imaging, PiFM provides a powerful new analytical method for deepening our understanding of nanomaterials. PMID:27051870

  8. Nanoscale chemical imaging by photoinduced force microscopy

    PubMed Central

    Nowak, Derek; Morrison, William; Wickramasinghe, H. Kumar; Jahng, Junghoon; Potma, Eric; Wan, Lei; Ruiz, Ricardo; Albrecht, Thomas R.; Schmidt, Kristin; Frommer, Jane; Sanders, Daniel P.; Park, Sung

    2016-01-01

    Correlating spatial chemical information with the morphology of closely packed nanostructures remains a challenge for the scientific community. For example, supramolecular self-assembly, which provides a powerful and low-cost way to create nanoscale patterns and engineered nanostructures, is not easily interrogated in real space via existing nondestructive techniques based on optics or electrons. A novel scanning probe technique called infrared photoinduced force microscopy (IR PiFM) directly measures the photoinduced polarizability of the sample in the near field by detecting the time-integrated force between the tip and the sample. By imaging at multiple IR wavelengths corresponding to absorption peaks of different chemical species, PiFM has demonstrated the ability to spatially map nm-scale patterns of the individual chemical components of two different types of self-assembled block copolymer films. With chemical-specific nanometer-scale imaging, PiFM provides a powerful new analytical method for deepening our understanding of nanomaterials. PMID:27051870

  9. Infrared-photoinduced-absorption studies in soluble trans-polyacetylene

    NASA Technical Reports Server (NTRS)

    Dorsinville, R.; Tubino, R.; Krimchansky, S.; Alfano, R. R.; Birman, J. L.

    1985-01-01

    The observation of photoinduced excitations in trans-polyacetylene in its liquid form in the frequency range from 2000 to 6000/cm is reported on. These measurements strongly suggest that transpolyacetylene is capable of supporting charged solitons even in solution.

  10. Photo-induced electron transfer method

    DOEpatents

    Wohlgemuth, Roland; Calvin, Melvin

    1984-01-01

    The efficiency of photo-induced electron transfer reactions is increased and the back transfer of electrons in such reactions is greatly reduced when a photo-sensitizer zinc porphyrin-surfactant and an electron donor manganese porphyrin-surfactant are admixed into phospho-lipid membranes. The phospholipids comprising said membranes are selected from phospholipids whose head portions are negatively charged. Said membranes are contacted with an aqueous medium in which an essentially neutral viologen electron acceptor is admixed. Catalysts capable of transfering electrons from reduced viologen electron acceptor to hydrogen to produce elemental hydrogen are also included in the aqueous medium. An oxidizable olefin is also admixed in the phospholipid for the purpose of combining with oxygen that coordinates with oxidized electron donor manganese porphyrin-surfactant.

  11. Photo-induced electron transfer method

    DOEpatents

    Wohlgemuth, R.; Calvin, M.

    1984-01-24

    The efficiency of photo-induced electron transfer reactions is increased and the back transfer of electrons in such reactions is greatly reduced when a photo-sensitizer zinc porphyrin-surfactant and an electron donor manganese porphyrin-surfactant are admixed into phospholipid membranes. The phospholipids comprising said membranes are selected from phospholipids whose head portions are negatively charged. Said membranes are contacted with an aqueous medium in which an essentially neutral viologen electron acceptor is admixed. Catalysts capable of transferring electrons from reduced viologen electron acceptor to hydrogen to produce elemental hydrogen are also included in the aqueous medium. An oxidizable olefin is also admixed in the phospholipid for the purpose of combining with oxygen that coordinates with oxidized electron donor manganese porphyrin-surfactant.

  12. Photoinduced Charge Separation in Molecular Silicon.

    PubMed

    Zhou, Jiawang; Surampudi, Sravan K; Bragg, Arthur E; Klausen, Rebekka S

    2016-04-25

    Interest in molecular silicon semiconductors arises from the properties shared with bulk silicon like earth abundance and the unique architectures accessible from a structure distinctly different than rigid π-conjugated organic semiconductors. We report ultrafast spectroscopic evidence for direct, photoinduced charge separation in molecular silicon semiconductors that supports the viability of molecular silicon as donor materials in optoelectronic devices. The materials in this study are σ-π hybrids, in which electron-deficient aromatic acceptors flank a σ-conjugated silicon chain. Transient absorption and femtosecond-stimulated Raman spectroscopy (FSRS) techniques revealed signatures consistent with direct, optical charge transfer from the silane chain to the acceptor; these signatures were only observed by probing excited-state structure. Our findings suggest new opportunities for controlling charge separation in molecular electronics. PMID:26919126

  13. [Development and synthetic application of epoxysilane rearrangement].

    PubMed

    Sasaki, Michiko

    2008-08-01

    O-Silyl cyanohydrins of beta-silyl-alpha,beta-epoxyaldehyde can function as a highly functionalized homoenolate equivalent via a tandem sequence involving base-promoted ring opening, Brook rearrangement, and alkylation at the allylic position. We named this rearrangement epoxysilane rearrangement. Based on results of mechanistic studies involving competitive experiments using diastereomeric cyanohydrins, we propose a reaction pathway involving a silicate intermediate formed by a concerted process via an anti-opening of the epoxide followed by the formation of an O-Si bond. Moreover, results of mechanistic studies on the rearrangement led to a conceptually novel approach to the chirality transfer in which epoxide chirality can be transferred into carbanion. We demonstrate the usefulness of the rearrangement through application to the following reactions: (1) reaction of gamma-p-toluenesulfonyl-alpha,beta-epoxysilane with alkyl halides and aldehydes followed by treatment with n-Bu4NF, which affords alpha,beta-unsaturated aldehydes (2) reaction of gamma-phosphonio-alpha,beta-epoxysilane with aldehydes, which affords dienol silyl ether derivatives (3) reaction of an enoate bearing an eposysilane moiety at the alpha-position with lithium enolate of 2-chloroacetamide, which affords highly functionalized cyclopropane derivatives. PMID:18670182

  14. FLNA genomic rearrangements cause periventricular nodular heterotopia

    PubMed Central

    Clapham, K.R.; Yu, T.W.; Ganesh, V.S.; Barry, B.; Chan, Y.; Mei, D.; Parrini, E.; Funalot, B.; Dupuis, L.; Nezarati, M.M.; du Souich, C.; van Karnebeek, C.

    2012-01-01

    Objective: To identify copy number variant (CNV) causes of periventricular nodular heterotopia (PNH) in patients for whom FLNA sequencing is negative. Methods: Screening of 35 patients from 33 pedigrees on an Affymetrix 6.0 microarray led to the identification of one individual bearing a CNV that disrupted FLNA. FLNA-disrupting CNVs were also isolated in 2 other individuals by multiplex ligation probe amplification. These 3 cases were further characterized by high-resolution oligo array comparative genomic hybridization (CGH), and the precise junctional breakpoints of the rearrangements were identified by PCR amplification and sequencing. Results: We report 3 cases of PNH caused by nonrecurrent genomic rearrangements that disrupt one copy of FLNA. The first individual carried a 113-kb deletion that removes all but the first exon of FLNA. A second patient harbored a complex rearrangement including a deletion of the 3′ end of FLNA accompanied by a partial duplication event. A third patient bore a 39-kb deletion encompassing all of FLNA and the neighboring gene EMD. High-resolution oligo array CGH of the FLNA locus suggests distinct molecular mechanisms for each of these rearrangements, and implicates nearby low copy repeats in their pathogenesis. Conclusions: These results demonstrate that FLNA is prone to pathogenic rearrangements, and highlight the importance of screening for CNVs in individuals with PNH lacking FLNA point mutations. Neurology® 2012;78:269–278 PMID:22238415

  15. Direct laser photo-induced fluorescence determination of bisphenol A.

    PubMed

    Maroto, Alicia; Kissingou, Prosnick; Diascorn, Alexandre; Benmansour, Badr; Deschamps, Laure; Stephan, Ludovic; Cabon, Jean-Yves; Giamarchi, Philippe

    2011-11-01

    Classical photo-induced fluorescence methods are conducted in two steps: a UV irradiation step in order to form a photo-induced compound followed by its fluorimetric determination. Automated flow injection methods are frequently used for these analyses. In this work, we propose a new method of direct laser photo-induced fluorescence analysis. This new method is based on direct irradiation of the analyte in a fluorimetric cell in order to form a photo-induced fluorescent compound and its direct fluorimetric detection during a short irradiation time. Irradiation is performed with a tuneable Nd:YAG laser to select the optimal excitation wavelength and to improve the specificity. It has been applied to the determination of bisphenol A, an endocrine disrupter compound that may be a potential contaminant for food. Irradiation of bisphenol A at 230 nm produces a photo-induced compound with a much higher fluorescence quantum yield and specific excitation/emission wavelengths. In tap water, the fluorescence of bisphenol A increases linearly versus its concentration and, its determination by direct laser photo-induced fluorescence permits to obtain a low limit of detection of 17 μg L(-1). PMID:21904798

  16. Photoinduced electro-optics measurements of biosilica transformation to cristobalite

    SciTech Connect

    Fuchs, Ido; Aluma, Yaniv; Ilan, Micha; Kityk, Iwan; Mastai, Yitzhak

    2015-03-15

    In this paper we studied the photoinduced electro optics effects in the thermal transformation process of biosilica to cristobalite, at a relatively low temperature and ambient pressure. This process was characterized by a variety of standards techniques with emphasis on linear electro optic effect measurements. Overall we demonstrated that photoinduced electro optics measurements are very sensitive to the transformation from amorphous structure of silica in the natural sponge samples to laminar string morphology of cristobalite. With this technique we could probe the change in the samples chirality from achiral bio silica to chiral cristobalite structure. Furthermore it is shown that natural biosilica have photoinduced linear electro optics respond indicating the chiral natural of biosilica. - Graphical abstract: The phase transformation of biosilica from marine sponges to Cristobalite under thermal treatment was investigated using photoinduced electro optics measurements. The figure shows the changes of the electro-optic coefficient of cristobalite and biosilica. - Highlights: • We examine phase transformation of biosilica. • We report transition from amorphous biosilica to crystalline Cristobalite. • Biosilica transformation to Cristobalite at temperature of 850 °C. • Biosilica transformation is studied with photoinduced measurements. • We examine changes in the photoinduced linear electro optics properties.

  17. Tyrosine kinase gene rearrangements in epithelial malignancies

    PubMed Central

    Shaw, Alice T.; Hsu, Peggy P.; Awad, Mark M.; Engelman, Jeffrey A.

    2014-01-01

    Chromosomal rearrangements that lead to oncogenic kinase activation are observed in many epithelial cancers. These cancers express activated fusion kinases that drive the initiation and progression of malignancy, and often have a considerable response to small-molecule kinase inhibitors, which validates these fusion kinases as ‘druggable’ targets. In this Review, we examine the aetiologic, pathogenic and clinical features that are associated with cancers harbouring oncogenic fusion kinases, including anaplastic lymphoma kinase (ALK), ROS1 and RET. We discuss the clinical outcomes with targeted therapies and explore strategies to discover additional kinases that are activated by chromosomal rearrangements in solid tumours. PMID:24132104

  18. Algorithm to search for genomic rearrangements

    NASA Astrophysics Data System (ADS)

    Nałecz-Charkiewicz, Katarzyna; Nowak, Robert

    2013-10-01

    The aim of this article is to discuss the issue of comparing nucleotide sequences in order to detect chromosomal rearrangements (for example, in the study of genomes of two cucumber varieties, Polish and Chinese). Two basic algorithms for detecting rearrangements has been described: Smith-Waterman algorithm, as well as a new method of searching genetic markers in combination with Knuth-Morris-Pratt algorithm. The computer program in client-server architecture was developed. The algorithms properties were examined on genomes Escherichia coli and Arabidopsis thaliana genomes, and are prepared to compare two cucumber varieties, Polish and Chinese. The results are promising and further works are planned.

  19. Thermal Claisen rearrangement of N-allylanilines

    SciTech Connect

    Abdrakhmanov, I.B.; Saraeva, Z.N.; Nigmatullin, N.G.; Tolstikov, G.A.

    1986-08-20

    Thermal Claisen rearrangement of N-allylanilines in undecane is accompanied by a parallel reaction involving elimination of the allyl fragment. The former reaction proceeds according to a (3,3)-sigmatropic mechanism with a varied structure of transition state, depending on the nature of the allyl substituent. The rearrangement of N-(2-chloro-1-methyl-2-butenyl)aniline has an autocatalytic nature on account of the HCl formed on elimination of the allyl fragment. The initial formation of an unreactive complex with composition (amine):(HCl) = 2:1, which decomposes by the action of a second HCl molecule, is postulated.

  20. Osteosarcoma With Apparent Ewing Sarcoma Gene Rearrangement.

    PubMed

    Mathias, Melissa D; Chou, Alexander J; Meyers, Paul; Shukla, Neerav; Hameed, Meera; Agaram, Narasimhan; Wang, Lu; Berger, Michael F; Walsh, Michael; Kentsis, Alex

    2016-07-01

    Poorly differentiated round cell sarcomas present diagnostic challenges because of their variable morphology and lack of specific immunophenotypic markers. We present a case of a 15-year-old female with a tibial tumor that exhibited features of Ewing-like sarcoma, including apparent rearrangement of the EWSR1 gene. Hybridization capture-based next-generation DNA sequencing showed evidence of complex genomic rearrangements, absence of known pathogenic Ewing-like chromosome translocations, and deletions RB1, PTCH1, and ATRX, supporting the diagnosis of osteosarcoma. This illustrates the potential of clinical genomic profiling to improve diagnosis and enable specifically targeted therapies for cancers with complex pathologies. PMID:27352193

  1. Synthesis of cationic dibenzosemibullvalene-based phase-transfer catalysts by di-π-methane rearrangements of pyrrolinium-annelated dibenzobarrelene derivatives

    PubMed Central

    Luo, Jia

    2011-01-01

    Summary Dibenzobarrelene derivatives, that are annelated with a pyrrolinium unit [N,N-dialkyl-3,4-(9',10'-dihydro-9',10'-anthraceno-3-pyrrolinium) derivatives], undergo a photo-induced di-π-methane rearrangement upon triplet sensitization to give the corresponding cationic dibenzosemibullvalene derivatives [N,N-dialkyl-3,4-{8c,8e-(4b,8b-dihydrodibenzo[a,f]cyclopropa[cd]pentaleno)}pyrrolidinium derivatives]. Whereas the covalent attachment of a benzophenone functionality to the pyrrolinium nitrogen atom did not result in an internal triplet sensitization, the introduction of a benzophenone unit as part of the counter ion enables the di-π-methane rearrangement of the dibenzobarrelene derivative in the solid-state. Preliminary experiments indicate that a cationic pyrrolidinium-annelated dibenzosemibullvalene may act as phase-transfer catalyst in alkylation reactions. PMID:21448242

  2. Overexpression of G100S mutation in PRKAG2 causes Wolff-Parkinson-White syndrome in zebrafish.

    PubMed

    Zhang, B L; Ye, Z; Xu, R L; You, X H; Qin, Y W; Wu, H; Cao, J; Zhang, J L; Zheng, X; Zhao, X X

    2014-09-01

    The Wolff-Parkinson-White (WPW) syndrome was believed to be associated with PRKAG2 gene mutations. In this study, we verified the pathopoiesis of G100S mutation, a novel mutation only discovered in Chinese patients with WPW, in cardiac disorder. Similar to R302Q, when overexpressed PRKAG2 G100S mutant in zebrafish, we observed a thicker heart wall, detected a decreased AMPK enzymatic activity by tissue AMPK kinase activity colorimetric technique, as well as examined an increased glycogen storage in heart wall using the method for periodic acid-Schiff staining, in comparison with the zebrafish without exogenous PRKAG2 (mock) or with wild-type PRKAG2 (WT). Taken together, we concluded PRKAG2 G100S mutation might contribute to impair the AMP-activated protein kinase function, which resulted in increased cardiac glycogen storage, serving as a pathogenesis for WPW syndrome in Chinese. PMID:23992123

  3. Familial Hypertrophic cardiomyopathy with Wolff-Parkinson-White syndrome maps to a locus on chromosome 7q3.

    PubMed Central

    MacRae, C A; Ghaisas, N; Kass, S; Donnelly, S; Basson, C T; Watkins, H C; Anan, R; Thierfelder, L H; McGarry, K; Rowland, E

    1995-01-01

    We have mapped a disease locus for Wolff-Parkinson-White syndrome (WPW) and familial hypertrophic cardiomyopathy (FHC) segregating in a large kindred to chromosome 7 band q3. Although WPW syndrome and FHC have been observed in members of the same family in prior studies, the relationship between these two diseases has remained enigmatic. A large family with 25 surviving individuals who are affected by one or both of these conditions was studied. The disease locus is closely linked to loci D7S688, D7S505, and D7S483 (maximum two point LOD score at D7S505 was 7.80 at theta = 0). While four different FHC loci have been described this is the first locus that can be mutated to cause both WPW and/or FHC. PMID:7657794

  4. Wolff-Parkinson-White syndrome type B and left bundle-branch block: electrophysiologic and radionuclide study

    SciTech Connect

    Rakovec, P.; Kranjec, I.; Fettich, J.J.; Jakopin, J.; Fidler, V.; Turk, J.

    1985-01-01

    Coinciding left bundle-branch block and Wolff-Parkinson-White syndrome type B, a very rare electrocardiographic occurrence, was found in a patient with dilated cardiomyopathy. Electrophysiologic study revealed eccentric retrograde atrial activation during ventricular pacing, suggesting right-sided accessory pathway. At programmed atrial pacing, effective refractory period of the accessory pathway was 310 ms; at shorter pacing coupling intervals, normal atrioventricular conduction with left bundle-branch block was seen. Left bundle-branch block was seen also with His bundle pacing. Radionuclide phase imaging demonstrated right ventricular phase advance and left ventricular phase delay; both right and left ventricular phase images revealed broad phase distribution histograms. Combined electrophysiologic and radionuclide investigations are useful to disclose complex conduction abnormalities and their mechanical correlates.

  5. Facility rearrangement scoping study: Draft letter report

    SciTech Connect

    Not Available

    1987-04-17

    We assessed the feasibility of designing the salt repository layouts so that shafts, surface structures and facilities would be totally within the north-east (NE) and center-east (CE) (one square mile) sections of the 9 square mile Deaf Smith site. With the latest version of the SCP-Conceptual Design as the basis, rearrangement analyses were conducted for the surface and subsurface layouts. For the rearranged layouts that were workable, impact assessments, relative to the SCP-Conceptual Design, were performed. This study concluded that, on a qualitative basis, the salt repository surface facilities can be relocated to within the north-east and center-east sections of the site. A suitable subsurface layout can be designed to accommodate this rearrangement. The resultant surface rearrangement is depicted. The two study sections (NE and CE) are emphasized on this figure. For reference, the location of the surface facilities in the SCP-Conceptual Design is also shown. 11 refs., 1 tab.

  6. Dynamics of Genome Rearrangement in Bacterial Populations

    PubMed Central

    Darling, Aaron E.; Miklós, István; Ragan, Mark A.

    2008-01-01

    Genome structure variation has profound impacts on phenotype in organisms ranging from microbes to humans, yet little is known about how natural selection acts on genome arrangement. Pathogenic bacteria such as Yersinia pestis, which causes bubonic and pneumonic plague, often exhibit a high degree of genomic rearrangement. The recent availability of several Yersinia genomes offers an unprecedented opportunity to study the evolution of genome structure and arrangement. We introduce a set of statistical methods to study patterns of rearrangement in circular chromosomes and apply them to the Yersinia. We constructed a multiple alignment of eight Yersinia genomes using Mauve software to identify 78 conserved segments that are internally free from genome rearrangement. Based on the alignment, we applied Bayesian statistical methods to infer the phylogenetic inversion history of Yersinia. The sampling of genome arrangement reconstructions contains seven parsimonious tree topologies, each having different histories of 79 inversions. Topologies with a greater number of inversions also exist, but were sampled less frequently. The inversion phylogenies agree with results suggested by SNP patterns. We then analyzed reconstructed inversion histories to identify patterns of rearrangement. We confirm an over-representation of “symmetric inversions”—inversions with endpoints that are equally distant from the origin of chromosomal replication. Ancestral genome arrangements demonstrate moderate preference for replichore balance in Yersinia. We found that all inversions are shorter than expected under a neutral model, whereas inversions acting within a single replichore are much shorter than expected. We also found evidence for a canonical configuration of the origin and terminus of replication. Finally, breakpoint reuse analysis reveals that inversions with endpoints proximal to the origin of DNA replication are nearly three times more frequent. Our findings represent the

  7. Deep cytoplasmic rearrangements in ventralized Xenopus embryos

    NASA Technical Reports Server (NTRS)

    Brown, E. E.; Denegre, J. M.; Danilchik, M. V.

    1993-01-01

    Following fertilization in Xenopus, dramatic rearrangements of the egg cytoplasm relocalize maternally synthesized egg components. During the first cell cycle the vegetal yolk mass rotates relative to the egg surface, toward the sperm entry point (SEP) (J. P. Vincent, G. F. Oster, and J. C. Gerhart, 1986, Dev. Biol. 113, 484-500), while concomitant deep cytoplasmic rearrangements occur in the animal hemisphere (M. V. Danilchik and J. M. Denegre, 1991, Development 111, 845-856). In this paper we examine the role of vegetal yolk mass rotation in producing the animal cytoplasmic rearrangements. We inhibited rotation by uv-irradiating embryos during the first cell cycle, a treatment that yields an extremely ventralized phenotype. Both uv-irradiated embryos and unirradiated control embryos show cytoplasmic rearrangements in the animal hemisphere during the first cell cycle. Cytoplasmic rearrangements on the SEP side of the embryo associated with the path of the sperm pronucleus, plus a swirl on the anti-SEP (dorsal) side, are seen, whether or not yolk mass rotation has occurred. This result suggests a role for the expanding sperm aster in directing animal hemisphere cytoplasmic movements. In unirradiated control embryos the anti-SEP (dorsal) swirl is larger than that in uv-irradiated embryos and often extends into the vegetal hemisphere, consistent with the animal cytoplasm having been pulled dorsally and vegetally by the sliding vegetal yolk mass. Thus the yolk mass rotation may normally enhance the dorsalward cytoplasmic movement, begun by the sperm aster, enough to induce normal axis formation. We extended our observations of unirradiated control and uv-irradiated embryos through early cleavages. The vegetal extent of the anti-SEP (dorsal) swirl pattern seen in control embryos persists through the early cleavage period, such that labeled animal cytoplasm extends deep into dorsal third-tier blastomeres at the 32-cell stage. Significantly, in uv-irradiated embryos

  8. The nature and role of bridged carbonyl intermediates in theultrafast photo-induced rearrangement of Ru3(CO)12.

    SciTech Connect

    Glascoe, Elizabeth A.; Kling, Matthias F.; Shanoski, Jennifer E.; Harris, Charles B.

    2005-09-18

    The photochemistry of the trimetal cluster,Ru(3)(CO)12, was investigated on the ultrafast timescale using UV-vis pump, infrared probe spectroscopy in order to study the transient intermediates formed upon photoexcitation.

  9. Methods for Detecting Chromosome Rearrangements in Gibberella Zeae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chromosome rearrangements between fungal strains may reduce fertility in sexual crosses through the production of genetically inviable recombinant progeny. As such, rearrangements can be important postzygotic reproductive barriers that contribute to the speciation process. The presence of chromosom...

  10. Photoinduced anchoring on a chalcogenide surface

    NASA Astrophysics Data System (ADS)

    Sheremet, N.; Kurioz, Yu.; Klebanov, M.; Lyubin, V.; Slyusarenko, K.; Reznikov, Yu.

    2012-05-01

    We present basic characteristics and a model of photoinduced anchoring of liquid crystals (LCs) on a chalcogenide surface. It was found that characteristics of the alignment strongly depend on the LC material for the same chalcogenide glass. The photoalignment is partially reversible and can be controlled by changing the light polarization direction. We propose a model in which the existence of dichroic units on the chalcogenide surface and competition between two mechanisms of the photoalignment is suggested. The first mechanism is related to the light-induced anisotropy on the chalcogenide surface and results in an easy orientation axes of a LC parallel to the polarization of the incident light. The second mechanism is attributed to an energy transfer from the dichroic units after the light absorption to the LC molecules adsorbed on the chalcogenide surface. The transferred energy causes polarization-sensitive desorption of the LC molecules from the chalcogenide surface and the light-induced easy orientation axis of a LC perpendicular to the incident light polarization. The competition between these mechanisms leads to the observed change of the direction of the easy axis with the exposure.

  11. Photoinduced electron transfer in ordered polymers

    SciTech Connect

    Jones, G. II.

    1991-12-01

    Long range photoinduced electron transfer between electron donor and acceptor groups is of considerable current interest in terms of strategies for artificial photosynthesis and studies regarding the redox properties of proteins. As part of an extensive study of long range electron transfer involving biopolymers, we have carried out this year investigations of the assembly of electron transfer agents in a system of model short peptides. Also studied is a polyelectrolyte that can adopt a helical conformation when electrostatically complexed with organic dye counter-ions. The principal interest in these systems has to do with the well ordered secondary structures adopted by peptide polymers, and the capabilities for synthetic modification of peptide side chains and end groups with chromophores or electroactive substituents. The present report gives a brief account of the following elements of work related to photochemical electron transfer themes: (1) the synthesis and photochemical characterization of chromophore-bound peptides and amino acid model compounds based on the amino acids, tryptophan and the spacer residue, alanine (Ala); (2) the study of binding of the cationic organic dye to a peptide electrolyte, for which cooperative dye loading and helix formation is important; and (3) completion of the synthesis of a new series of acridinium chromophores that have rod-like'' arrangements of inked aryl rings for assembly of electron donor-acceptor systems that will exhibit especially long lived charge separation.

  12. Photoinduced electron transfer in a porphyrin dyad

    SciTech Connect

    Gust, D.; Moore, T.A.; Moore, A.L.; Leggett, L.; Lin, S.; DeGraziano, J.M.; Hermant, R.M.; Nicodem, D.; Craig, P.; Seely, G.R.; Nieman, R.A. )

    1993-07-29

    A prophyrin dyad designed to facilitate vectorial interporphyrin electron transfer has been synthesized and studied using steady-state and time-resolved absorption and emission spectroscopies. The dyad features a zinc tetraaylporphyrin bearing electron-donating substituents linked by an amide bond to a free base porphyrin carrying electron-withdrawing groups. Excitation of the zinc porphyrin moiety in dichloromethane solution is followed by singlet energy transfer to the free base and concurrent electron transfer to the same moiety to yield a charge-separated state. The free base first excited singlet state decays by accepting an electron from the zinc porphyrin to form the same charge-separated state. Similar results are observed in butyronitrile. Transient absorption studies in butyronitrile verify the formation of a short-lived (8 ps) charge-separated state from the porphyrin first excited singlet states. The results support the suggestion that fluorescence quenching in related porphyrin dyads and carotenoid--diporphyrin triads is due to photoinduced electron transfer, rather than some other decay process. 17 refs., 8 refs.

  13. Photoinduced Energy Transfer in Artificial Photosynthetic Systems

    NASA Astrophysics Data System (ADS)

    Imahori, H.; Umeyama, T.

    Artificial photosynthesis is a current topic of intensive investigations, both in order to understand the reactions that play a central role in natural photosynthesis as well as to develop highly efficient solar energy conversion systems and molecular optoelectronic devices [1-34]. Artificial photosynthesis is defined as a research field that attempts to mimic the natural process of photosynthesis. Therefore, the outline of natural photosynthesis is described briefly for the better understanding of artificial photosynthesis . Natural photosynthetic system is regarded as one of the most elaborate nanobiological machines [35,36]. It converts solar energy into electrochemical potential or chemical energy, which is prerequisite for the living organisms on the earth. The core function of photosynthesis is a cascade of photoinduced energy and electron transfer between donors and acceptors in the antenna complexes and the reaction center. For instance, in purple photosynthetic bacteria (Rhodopseudomonas acidophila and Rhodopseudomonas palustris) there are two different types of antenna complexes: a core light-harvesting antenna (LH1) and peripheral light-harvesting antenna (LH2) [37-39]. LH1 surrounds the reaction center where charge separation takes place.

  14. Dynamics of photoinduced cell plasma membrane injury.

    PubMed Central

    Thorpe, W P; Toner, M; Ezzell, R M; Tompkins, R G; Yarmush, M L

    1995-01-01

    We have developed a video microscopy system designed for real-time measurement of single cell damage during photolysis under well defined physicochemical and photophysical conditions. Melanoma cells cultured in vitro were treated with the photosensitizer (PS), tin chlorin e6 (SnCe6) or immunoconjugate (SnCe6 conjugated to a anti-ICAM monoclonal antibody), and illuminated with a 10 mW He/Ne laser at a 630 nm wavelength. Cell membrane integrity was assessed using the vital dye calcein-AM. In experiments in which the laser power density and PS concentration were varied, it was determined that the time lag before cell rupture was inversely proportional to the estimated singlet oxygen flux to the cell surface. Microscopic examination of the lytic event indicated that photo-induced lysis was caused by a point rupture of the plasma membrane. The on-line nature of this microscopy system offers an opportunity to monitor the dynamics of the cell damage process and to gain insights into the mechanism governing photolytic cell injury processes. Images FIGURE 2 FIGURE 3 FIGURE 6 FIGURE 7 PMID:7612864

  15. Photoinduced carrier annihilation in silicon pn junction

    NASA Astrophysics Data System (ADS)

    Sameshima, Toshiyuki; Motoki, Takayuki; Yasuda, Keisuke; Nakamura, Tomohiko; Hasumi, Masahiko; Mizuno, Toshihisa

    2015-08-01

    We report analysis of the photo-induced minority carrier effective lifetime (τeff) in a p+n junction formed on the top surfaces of a n-type silicon substrate by ion implantation of boron and phosphorus atoms at the top and bottom surfaces followed by activation by microwave heating. Bias voltages were applied to the p+ boron-doped surface with n+ phosphorus-doped surface kept at 0 V. The values of τeff were lower than 1 × 10-5 s under the reverse-bias condition. On the other hand, τeff markedly increased to 1.4 × 10-4 s as the forward-bias voltage increased to 0.7 V and then it leveled off when continuous-wave 635 nm light was illuminated at 0.74 mW/cm2 on the p+ surface. The carrier annihilation velocity S\\text{p + } at the p+ surface region was numerically estimated from the experimental τeff. S\\text{p + } ranged from 4000 to 7200 cm/s under the reverse-bias condition when the carrier annihilation velocity S\\text{n + } at the n+ surface region was assumed to be a constant value of 100 cm/s. S\\text{p + } markedly decreased to 265 cm/s as the forward-bias voltage increased to 0.7 V.

  16. Inactivation of tyrosinase photoinduced by pterin

    SciTech Connect

    Laura Dantola, M.; Gojanovich, Aldana D.; Thomas, Andres H.

    2012-08-03

    Highlights: Black-Right-Pointing-Pointer Under UV-A radiation, tirosinase is photoinactivated by pterin. Black-Right-Pointing-Pointer The mechanism involves an electron transfer-initiated process. Black-Right-Pointing-Pointer The photochemical process affects both activities of tyrosinase. -- Abstract: Tyrosinase catalyzes in mammals the first and rate-limiting step in the biosynthesis of the melanin, the main pigment of the skin. Pterins, heterocyclic compounds able to photoinduce oxidation of DNA and its components, accumulate in the skin of patients suffering from vitiligo, a chronic depigmentation disorder in which the protection against UV radiation fails due to the lack of melanin. Aqueous solutions of tyrosinase were exposed to UV-A irradiation (350 nm) in the presence of pterin, the parent compound of oxidized pterins, under different experimental conditions. The enzyme activity in the irradiated solutions was determined by spectrophotometry and HPLC. In this work, we present data that demonstrate unequivocally that the enzyme is photoinactivated by pterin. The mechanism of the photosensitized process involves an electron transfer from tyrosinase to the triplet excited state of pterin, formed after UV-A excitation of pterin. The biological implications of the results are discussed.

  17. Manipulating photoinduced voltage in metasurface with circularly polarized light.

    PubMed

    Bai, Qiang

    2015-02-23

    Recently, the concept of metasurface has provided one an unprecedented opportunity and ability to control the light in the deep subwavelength scale. However, so far most efforts are devoted to exploiting the novel scattering properties and applications of metasurface in optics. Here, I theoretically and numerically demonstrate that longitudinal and transverse photoinduced voltages can be simultaneously realized in the proposed metasurface utilizing the magnetic resonance under the normal incidence of circularly polarized light, which may extend the concept and functionality of metasurface into the electronics and may provide a potential scheme to realize a nanoscale tunable voltage source through a nanophotonic roadmap. The signs of longitudinal and transverse photoin-duced voltages can be manipulated by tuning the resonant frequency and the handedness of circularly polarized light, respectively. Analytical formulae of photoinduced voltage are presented based on the theory of symmetry of field. This work may bridge nanophotonics and electronics, expands the capability of metasurface and has many potential applications. PMID:25836566

  18. Photoinduced electro-optics measurements of biosilica transformation to cristobalite

    NASA Astrophysics Data System (ADS)

    Fuchs, Ido; Aluma, Yaniv; Ilan, Micha; Kityk, Iwan; Mastai, Yitzhak

    2015-03-01

    In this paper we studied the photoinduced electro optics effects in the thermal transformation process of biosilica to cristobalite, at a relatively low temperature and ambient pressure. This process was characterized by a variety of standards techniques with emphasis on linear electro optic effect measurements. Overall we demonstrated that photoinduced electro optics measurements are very sensitive to the transformation from amorphous structure of silica in the natural sponge samples to laminar string morphology of cristobalite. With this technique we could probe the change in the samples chirality from achiral bio silica to chiral cristobalite structure. Furthermore it is shown that natural biosilica have photoinduced linear electro optics respond indicating the chiral natural of biosilica.

  19. Dynamics of a photoinduced phase transition in polydiacetylene crystals

    NASA Astrophysics Data System (ADS)

    Koshihara, S.; Tokura, Y.; Takeda, K.; Koda, T.

    1995-09-01

    The dynamical process of the photoinduced phase transition in polydiacetylene (PDA) single crystals has been investigated by time-resolved spectroscopy with varying temperature, excitation photon energy, and intensity. The photoinduced phase transition can be driven bidirectionally between the two (A and B) phases by dichromatic irradiation of a laser pulse, when the temperature of the PDA crystal is kept around the phase transition temperature (Tc). It was found that primary process of the photoinduced phase transition is mostly completed within 50 ns. In addition, occurrence of a transient domain injection has been confirmed at temperatures far below and above Tc. Together with the time-resolved measurement of photocurrent, we have found a close correlation between the photocurrent intensity and the phase conversion efficiency. This suggests that the domain walls separating the A and B phases can carry the charge.

  20. [Wolff-Parkinson-White syndrome with orthodromic supraventricular tachycardia associated with a "hyper-conductor" atrio-ventricular node. A therapeutic challenge].

    PubMed

    Hernández González, D; Iturralde Torres, P; Romero, L; Colín, L; Villarreal, A; González Hermosillo, J A

    1990-01-01

    One case of Wolff-Parkinson-White Syndrome with paroxysmal supraventricular tachycardia related to orthodromic atrioventricular reentry using an accessory pathway for retrograde conduction an a rapidly conducting AV node for anterograde conduction is present. The pharmacological therapy with Digoxin, Propranolol, Quinidine, Disopyramide and Propafenone was not effective. An electrophysiologic study showed a reciprocating tachycardia induced by spontaneous ventricular beats. Both the effective refractory period of the AV node and the anterograde effective refractory period of the accessory pathway were minor or equal to 220 msec which made the control of the arrhythmia difficult. Amiodarone was able to suppress the premature ventricular beats, depress conduction and prolong refractoriness in both, the AV node and accessory pathway to prevent recurrences of atrioventricular reentry. In this patient a false positive test with ajmaline was documented. The electrophysiologic study showed the association of Wolff-Parkinson-White Syndrome with an enhanced atrioventricular nodal-conduction and allowed the selection of an appropriate antiarrhythmic agent. PMID:2378538

  1. Sampling and counting genome rearrangement scenarios

    PubMed Central

    2015-01-01

    Background Even for moderate size inputs, there are a tremendous number of optimal rearrangement scenarios, regardless what the model is and which specific question is to be answered. Therefore giving one optimal solution might be misleading and cannot be used for statistical inferring. Statistically well funded methods are necessary to sample uniformly from the solution space and then a small number of samples are sufficient for statistical inferring. Contribution In this paper, we give a mini-review about the state-of-the-art of sampling and counting rearrangement scenarios, focusing on the reversal, DCJ and SCJ models. Above that, we also give a Gibbs sampler for sampling most parsimonious labeling of evolutionary trees under the SCJ model. The method has been implemented and tested on real life data. The software package together with example data can be downloaded from http://www.renyi.hu/~miklosi/SCJ-Gibbs/ PMID:26452124

  2. Rearrangements in 2-Dimensional Foam Simulations

    NASA Astrophysics Data System (ADS)

    Schiemann, Dylan; Tewari, Shubha; Liu, Andrea; Knobler, Charles; Durian, Douglas; Dennin, Michael; Langer, Stephen

    1998-03-01

    Foam is a collection of densely-packed polydisperse gas bubbles in liquid. Upon shear, the total interaction energy between bubbles fluctuates: it builds up and then is released via intermittent rearrangements of the bubbles. There is presently no effective experimental method for measuring these energy releases. However, it is possible to observe the relaxation of sheared foam through the analysis of topological rearrangements, or neighbor-switching events (T1 events) footnote A.D. Gopal and D.J. Durian, Phys. Rev. Lett. 75 2610 (1995) footnote M. Dennin and C.M. Knobler, Phys. Rev. Lett. 78 2485 (1997) We have used a simple two-dimensional model of foam proposed by Durian footnote D.J. Durian, Phys. Rev. Lett. 75 4780 (1995) to study rearrangements under steady-state shear flow. The aim is to study the connection between T1 events, which are typically measured experimentally, and the distribution of energy releases, which is typically measured from simulations. We find that T1 events tend to correspond to the largest energy releases. We present results as a function of strain rate and area fraction of bubbles.

  3. Photoinduced charge-separation in DNA.

    PubMed

    Kawai, Kiyohiko; Majima, Tetsuro

    2015-01-01

    DNA site-specifically modified with a photosensitizer (Sens) was synthesized and the charge-separation and charge-recombination dynamics in DNA were studied. We specifically focused on the formation of the long-lived charge-separated state whose lifetime (τ) is longer than 0.1 μs. The quantum yields of the formation of the charge-separated states (Φ) upon the photoexcitation of the Sens, and the τ were measured using the laser flash photolysis technique. We utilized naphthalimide (NI), naphthaldiimide (ND), and anthraquinone (AQ) as a Sens to investigate the mechanism of the formation of the charge-separated state in DNA via rapid positive charge (hole) transfer between adenine and thymine (A-T) base-pairs. By replacing some T bases in the A-T stretch with 5-bromouracil ((br)U), the charge-separation was shown to occur via the photoinduced charge-injection into the second and further neighboring As to the Sens. On the other hand, the generation of a hole on A nearest to Sens ends up with the rapid charge-recombination within a contact ion pair. A long-lived charge-separated state was also generated in DNA when a commonly used fluorophore such asTAMRA, Alexa 532, and ATTO 655, which can only oxidize guanine-cytosine (G-C) base-pair, but not A-T, was used as a Sens. These results suggested that the charge-separation in DNA is a general phenonmenon for fluorescent dyes which fluorescence is quenched only by G-C. PMID:24577608

  4. Photoinduced structural changes to protein kinase A

    NASA Astrophysics Data System (ADS)

    Rozinek, Sarah C.; Thomas, Robert J.; Brancaleon, Lorenzo

    2014-03-01

    The importance of porphyrins in organisms is underscored by the ubiquitous biological and biochemical functions that are mediated by these compounds and by their potential biomedical and biotechnological applications. Protoporphyrin IX (PPIX) is the precursor to heme and has biomedical applications such as its use as a photosensitizer in phototherapy and photodetection of cancer. Among other applications, our group has demonstrated that low-irradiance exposure to laser irradiation of PPIX, Fe-PPIX, or meso-tetrakis (4-sulfonatophenyl) porphyrin (TSPP) non-covalently docked to a protein causes conformational changes in the polypeptide. Such approach can have remarkable consequences in the study of protein structure/function relationship and can be used to prompt non-native protein properties. Therefore we have investigated protein kinase A (PKA), a more relevant protein model towards the photo-treatment of cancer. PKA's enzymatic functions are regulated by the presence of cyclic adenosine monophosphate for intracellular signal transduction involved in, among other things, stimulation of transcription, tumorigenesis in Carney complex and migration of breast carcinoma cells. Since phosphorylation is a necessary step in some cancers and inflammatory diseases, inhibiting the protein kinase, and therefore phosphorylation, may serve to treat these diseases. Changes in absorption, steady-state fluorescence, and fluorescence lifetime indicate: 1) both TSPP and PPIX non-covalently bind to PKA where they maintain photoreactivity; 2) absorptive photoproduct formation occurs only when PKA is bound to TSPP and irradiated; and 3) PKA undergoes secondary structural changes after irradiation with either porphyrin bound. These photoinduced changes could affect the protein's enzymatic and signaling capabilities.

  5. Nonlinearity in the dynamics of photoinduced nucleation process.

    PubMed

    Ishida, Kunio; Nasu, Keiichiro

    2008-03-21

    Coherent nonlinear dynamics of photoinduced cooperative phenomena at 0 K is studied by numerical calculations on a model of molecular crystals. We found that the photoinduced nucleation process is triggered only when a certain amount of excitation energy is supplied in a narrow part of the system; i.e., there exists the smallest size of the cluster of excited molecules which makes the nucleation possible. As a result, the portion of the cooperatively converted molecules is nonlinearly dependent on the photoexcitation strength, which has been observed in various materials. PMID:18517805

  6. Photoinduced charge separation by polymer-bound chromophores

    SciTech Connect

    Rodgers, M.A.J.

    1991-09-01

    This project has examined the photodynamic behavior of water-soluble polymers that have covalently linked hydrophobic chromophores spaced along the chains. These polymeric systems have been examined for photoinduced charge separation with electron-accepting ions having different total charge. Focus has been on the excited singlet (S{sub 1}) state formed by laser flash absorption. The effects of pH and ionic strength -- factors that govern the conformational nature of the polymer in solution -- have been studied. A second major effort has been to study photoinduced redox processes involving excited states of water-soluble variants of anthracene and acridine. 27 refs., 16 figs., 2 tabs.

  7. Photoinduced electron transfer in binary blends of conjugated polymers

    SciTech Connect

    Jenekhe, A.A.; Paor, L.R. de; Chen, X.L.; Tarkka, R.M.

    1996-10-01

    The authors report observations concerning the intermolecular photoinduced electron transfer through blends of n-type/p-type {pi}-conjugated organic polymers. The results of transient absorption spectroscopy, fluorescence quenching analysis, and delocalized radical ion pair generation studies imply that these materials are supramolecular materials.

  8. Spectra of thermoprogrammed annealing of photoinduced color centers

    NASA Astrophysics Data System (ADS)

    Glazkova, N. I.; Mikhaylov, R. V.; Kuznetsov, V. N.

    2015-04-01

    The kinetics of photoinduced formation and thermoprogrammed annealing of color centers in photochromic rutile ceramics has been studied in situ with the aid of a specially designed attachment for a spectrofluorimeter. Using a regime of constant heating rate, the spectra of color center annealing have been measured and the energy depths of hole traps responsible for the annealing of these centers have been determined.

  9. Photoinduced Bending of Self-Assembled Azobenzene-Siloxane Hybrid.

    PubMed

    Guo, Sufang; Matsukawa, Kimihiro; Miyata, Takashi; Okubo, Tatsuya; Kuroda, Kazuyuki; Shimojima, Atsushi

    2015-12-16

    A novel azobenzene-siloxane hybrid material displaying photoinduced macroscopic motions has been prepared by one-step organosilane self-assembly. Two types of alkoxysilane precursors with either pendant or bridging azobenzene groups were synthesized via thiol-ene click reactions. Hybrid films with well-ordered lamellar structures were obtained by hydrolysis and polycondensation of these precursors. The film with solely pendant azobenzene groups showed reversible and rapid d-spacing variation upon UV-vis irradiation, which was induced by the trans-cis isomerization of azobenzene moieties. The flexible, free-standing film obtained by co-condensation of two types of precursors showed reversible bending-unbending motions upon UV-vis irradiation. The partial cross-linking between the siloxane layers by bridging azobenzene groups was crucial for photoinduced distortion of the film. This film possesses high elastic modulus, good thermal stability, and shows large amplitude of photoinduced bending-unbending over a wide temperature range. This is the first report on photoinduced macroscopic motions of azobenzene-containing siloxane-based materials. These materials possess great potential for applications in smart devices and energy conversion systems. PMID:26575345

  10. Measurements of Photo-induced Changes in Conjugated Polymers

    DOE R&D Accomplishments Database

    Seager, C. H.; Sinclair, M. B.; Mc Branch, D.; Heeger, A. J.; Baker, G. L.

    1991-01-01

    We have used the highly sensitive technique of Photothermal Deflection Spectroscopy (PDS) to measure changes in the infrared absorption spectra of MEHPPV, P3HT and Polydiacetylene-4BCMU induced by pumping these polymers with light above the {pi} - {pi}* transition energy. In contrast to previous chopped light transmission measurements of these effects, the PDS technique can directly measure the buildup or decay of the absorption coefficient, {alpha}, on the time scale of second to days. In the case of MEHPPV we observe that the time scale of seconds to days. In the case of MEHPPV we observe that above-gap light causes the appearance of a broad infrared peak in {alpha}, which continues to grow-in hours after the pump light is first applied. For this polymer the general shape of the absorption spectra in the unpumped state mimics the photo-induced changes, suggesting that remnant photo-induced states determine the maximum transparency observed under normal experimental conditions. For P3HT and to a lesser extent, MEHPPV, we also observe irreversible photo-induced absorption components which we tentatively identify with photo-induced oxidation of the polymer matrix.

  11. Effect of humidity and temperature on photoinduced reactions in cellulose

    NASA Astrophysics Data System (ADS)

    Murtagh, James; Thomas, J. Kerry

    1988-07-01

    Pulsed laser studies and phosphorimetry have been used to investigate the reaction of O 2 and methyl viologen with the triplet excited state of tetramethylbenzidene in cellophane. Small amounts of water markedly affect the photoinduced reactions. In the case of methyl viologen, electron transfer via tunnelling is observed to give reduced methyl viologen.

  12. A general heuristic for genome rearrangement problems.

    PubMed

    Dias, Ulisses; Galvão, Gustavo Rodrigues; Lintzmayer, Carla Négri; Dias, Zanoni

    2014-06-01

    In this paper, we present a general heuristic for several problems in the genome rearrangement field. Our heuristic does not solve any problem directly, it is rather used to improve the solutions provided by any non-optimal algorithm that solve them. Therefore, we have implemented several algorithms described in the literature and several algorithms developed by ourselves. As a whole, we implemented 23 algorithms for 9 well known problems in the genome rearrangement field. A total of 13 algorithms were implemented for problems that use the notions of prefix and suffix operations. In addition, we worked on 5 algorithms for the classic problem of sorting by transposition and we conclude the experiments by presenting results for 3 approximation algorithms for the sorting by reversals and transpositions problem and 2 approximation algorithms for the sorting by reversals problem. Another algorithm with better approximation ratio can be found for the last genome rearrangement problem, but it is purely theoretical with no practical implementation. The algorithms we implemented in addition to our heuristic lead to the best practical results in each case. In particular, we were able to improve results on the sorting by transpositions problem, which is a very special case because many efforts have been made to generate algorithms with good results in practice and some of these algorithms provide results that equal the optimum solutions in many cases. Our source codes and benchmarks are freely available upon request from the authors so that it will be easier to compare new approaches against our results. PMID:24969750

  13. A new class of rearrangeable interconnection networks

    SciTech Connect

    Douglass, B.G.

    1989-01-01

    With the current interest in general purpose multiprocessing systems and distributed processing networks, a need exists for rearrangeable interconnection networks. These networks can simultaneously transmit information from all sources to all destinations, for all possible combinations of destinations. Such networks exist, and among these the Benes network is of asymptotically optimal hardware complexity. However, this network requires excessive time to recompute the switch settings each time a new set of transmissions is requested by the source processors. Some algorithms exist to reduce this time overhead but they require excessive hardware to compute the settings. This thesis introduces a new class of rearrangeable networks, called reduced networks, based on an extension of Clos three-stage networks. It is shown that the switches in the first and third stages of Clos networks can be constructed as unique path logarithmic networks. Only the center-stage switches must be rearrangeable. This fact is then used to develop a compact network structure. The routing properties of this structure are defined, and it is shown that there is a connectivity in the setting of the switches for any Clos network. An upper and lower bound on this connectivity are established, leading to a fast routing algorithm, with a trade off between the routing time and the network hardware complexity. This can be exploited by the network designer to achieve the best combination of hardware cost and data transfer rate for the particular application. For network sizes contemplated within the foreseeable future, the resulting design will in most cases be closer to the ideal combination than any other network.

  14. Nonclassical 21-Homododecahedryl Cation Rearrangement Revisited.

    PubMed

    Jalife, Said; Mondal, Sukanta; Osorio, Edison; Cabellos, José Luis; Martínez-Guajardo, Gerardo; Fernández-Herrera, María A; Merino, Gabriel

    2016-03-01

    The degenerate rearrangement in the 21-homododecahedryl cation (1) has been studied via density functional theory computations and Born-Oppenheimer Molecular Dynamics simulations. Compound 1 can be described as a highly fluxional hyperconjugated carbocation. Complete scrambling of 1 can be achieved by the combination of two unveiled barrierless processes. The first one is a "rotation" of one of the six-membered rings via a 0.8 kcal·mol(-1) barrier, and the second one is a slower interconvertion between two hyperconjomers via an out-of-plane methine bending (ΔG(⧧) = 4.0 kcal·mol(-1)). PMID:26862680

  15. Catalytic Environmentally Friendly Protocol for Achmatowicz Rearrangement.

    PubMed

    Li, Zhilong; Tong, Rongbiao

    2016-06-01

    The increasing interest in Achmatowicz rearrangement in organic synthesis calls for a more environmentally friendly protocol since the most popular oxidants m-CPBA and NBS produced stoichiometric organic side product (m-chlorobenzoic acid or succinimide). Mechanism-guided analysis enables us to develop a new catalytic method (Oxone/KBr) for AchR in excellent yield with K2SO4 as the only side product, which greatly facilitates the purification. This protocol was integrated with other transformations, leading to a rapid access to the highly functionalized dihydropyranones. PMID:27167167

  16. A young patient with atypical type-B Wolff-Parkinson-White syndrome accompanied by left ventricular dysfunction.

    PubMed

    Takeuchi, Takahiro; Tomita, Takeshi; Kasai, Hiroki; Kashiwagi, Daisuke; Yoshie, Koji; Yaguchi, Tomonori; Oguchi, Yasutaka; Kozuka, Ayako; Gautam, Milan; Motoki, Hirohiko; Okada, Ayako; Shiba, Yuji; Aizawa, Kazunori; Izawa, Atsushi; Miyashita, Yusuke; Koyama, Jun; Hongo, Minoru; Ikeda, Uichi

    2015-02-01

    A 15-year-old asymptomatic male patient presented with an electrocardiographic abnormality and left ventricular (LV) dysfunction (left ventricle ejection fraction of 40%) in a physical examination performed 2 years previously. LV dysfunction did not improve despite optimal medical therapy for dilated cardiomyopathy. Twelve-lead electrocardiography revealed a normal PR interval (138 ms) with a small delta-like wave in V2, but not a typical diagnostic wave that could be diagnosed as Wolff-Parkinson-White (WPW) syndrome by an electrocardiogram auto-analysis. Transthoracic echocardiography showed a remarkable asynchronous septal motion. An electrophysiological study was performed to exclude WPW syndrome. An accessory pathway (AP) was revealed on the lateral wall of the right ventricle, and radiofrequency catheter ablation was successfully performed to disconnect the AP. Thereafter, the dyssynchrony disappeared, and LV function improved. The intrinsic atrioventricular nodal conduction was very slow (A-H, 237 ms). The results of electrocardiogram auto-analysis could not be used to confirm the diagnosis of WPW syndrome because of the atypical delta wave. Conduction via the right lateral AP caused electrical dyssynchrony in the LV. This case suggests that atypical delta waves should be evaluated without depending on electrocardiographic auto-analyses in patients with LV dysfunction accompanied by dyssynchrony. PMID:26336525

  17. [Cardioversion for paroxysmal supraventricular tachycardia during lung surgery in a patient with concealed Wolff-Parkinson-White syndrome].

    PubMed

    Sato, Yoshiharu; Nagata, Hirofumi; Inoda, Ayako; Miura, Hiroko; Watanabe, Yoko; Suzuki, Kenji

    2014-10-01

    We report a case of paroxysmal supraventricular tachycardia (PSVT) that occurred during video-assisted thoracoscopic (VATS) lobectomy in a patient with concealed Wolff-Parkinson-White (WPW) syndrome. A 59-year-old man with lung cancer was scheduled for VATS lobectomy under general anesthesia. After inserting a thoracic epidural catheter, general anesthesia was induced with intravenous administration of propofol. Anesthesia was maintained with inhalation of desfurane in an air/oxygen mixture and intravenous infusion of remifentanil. Recurrent PSVT occurred three times, and the last episode of PSVT continued for 50 minutes regardless of administration of antiarrhythmic drugs. Synchronized electric shock via adhesive electrode pads on the patient's chest successfully converted PSVT back to normal sinus rhythm. The remaining course and postoperative period were uneventful. An electrophysiological study performed after hospital discharge detected concealed WPW syndrome, which had contributed to the development of atrioventricular reciprocating tachycardia. Concealed WPW syndrome is a rare, but critical complication that could possibly cause lethal atrial tachyarrhythmias during the perioperative period. In the present case, cardioversion using adhesive electrode pads briefly terminated PSVT in a patient with concealed WPW syndrome. PMID:25693338

  18. Mutation of mitochondrial DNA G13513A presenting with Leigh syndrome, Wolff-Parkinson-White syndrome and cardiomyopathy.

    PubMed

    Wang, Shi-Bing; Weng, Wen-Chin; Lee, Ni-Chung; Hwu, Wuh-Liang; Fan, Pi-Chuan; Lee, Wang-Tso

    2008-08-01

    Mutation of mitochondrial DNA (mtDNA) G13513A, encoding the ND5 subunit of respiratory chain complex I, can cause mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) and Leigh syndrome. Wolff-Parkinson-White (WPW) syndrome and optic atrophy were reported in a high proportion of patients with this mutation. We report an 18-month-old girl, with an 11-month history of psychomotor regression who was diagnosed with WPW syndrome and hypertrophic cardiomyopathy, in association with Leigh syndrome. Supplementation with coenzyme Q10, thiamine and carnitine prevented further regression in gross motor function but the patient's heart function deteriorated and dilated cardiomyopathy developed 11 months later. She was found to have a mutation of mtDNA G13513A. We suggest that mtDNA G13513A mutation is an important factor in patients with Leigh syndrome associated with WPW syndrome and/or optic atrophy, and serial heart function monitoring by echocardiography is recommended in this group of patients. PMID:19054921

  19. Phase analysis in the Wolff-Parkinson-White syndrome with surgically proven accessory conduction pathways: concise communication

    SciTech Connect

    Nakajima, K.; Bunko, H.; Tada, A.; Taki, J.; Tonami, N.; Hisada, K.; Misaki, T.; Iwa, T.

    1984-01-01

    Twenty-one patients with the Wolff-Parkinson-White (WPW) syndrome who underwent surgical division of the accessory conduction pathway (ACP) were studied by gated blood-pool scintigraphy. In each case, a functional image of the phase was generated, based on the fundamental frequency of the Fourier transform. The location of the ACP was confirmed by electrophysiologic study, epicardial mapping, and surgery. Phase analysis identified the side of preexcitation correctly in 16 out of 20 patients with WPW syndrome with a delta wave. All patients with right-cardiac type (N=9) had initial contraction in the right ventricle (RV). In patients with left-cardiac type (N=10), six had initial movement in the left ventricle (LV); but in the other four the ACPs in the anterior or lateral wall of the left ventricle (LV) could not be detected. In patients with multiple ACPs (N=2), one right-cardiac type had initial contraction in the RV, while in the other (with an intermittent WPW syndrome) the ACP was not detected. These observations indicate that abnormal wall motion is associated with the conduction anomalies of the WPW syndrome. We conclude that phase analysis can correctly identify the side of initial contraction in the WPW syndrome before and after surgery. However, as a method of preoperative study, it seems difficult to determine the precise site of the ACP by phase analysis alone.

  20. Parametric imaging of experimentally simulated Wolff-Parkinson-White syndrome conduction abnormalities in dogs: a concise communication

    SciTech Connect

    Weismueller, P.H.; Henze, E.; Adam, W.E.; Roth, J.; Bitter, F.; Stauch, M.

    1986-01-01

    In order to test the diagnostic potential of phase analysis of radionuclide ventriculography (RNV) for localizing accessory bundles in Wolff-Parkinson-White (WPW) syndrome, 24 experimental runs were performed in three open chest instrumented dogs. After a baseline study, WPW syndrome was simulated by stimulation at seven different sites around the base of the ventricles, and RNV's were obtained. Subsequent data processing including Fourier transformation allowed the localization of the site of the first inward motion of the ventricles by an isophasic wave display. In sinus rhythm, the septum contracted first. During ectopic premature ventricular stimulation by triggering the atrial signal, the phase scan was altered only when the stimulus was applied earlier than 20 ms before the expected QRS complex during sinus rhythm. During stimulation with fixed frequency, only the left lateral positions of the premature stimulation were detected by phase analysis with a sensitivity of 86%. Neither the antero- or posteroseptal nor the right ventricular premature contraction pattern could be exactly localized.

  1. Structures of Local Rearrangements in Soft Colloidal Glasses

    NASA Astrophysics Data System (ADS)

    Yang, Xiunan; Liu, Rui; Yang, Mingcheng; Wang, Wei-Hua; Chen, Ke

    2016-06-01

    We image local structural rearrangements in soft colloidal glasses under small periodic perturbations induced by thermal cycling. Local structural entropy S2 positively correlates with observed rearrangements in colloidal glasses. The high S2 values of the rearranging clusters in glasses indicate that fragile regions in glasses are structurally less correlated, similar to structural defects in crystalline solids. Slow-evolving high S2 spots are capable of predicting local rearrangements long before the relaxations occur, while fluctuation-created high S2 spots best correlate with local deformations right before the rearrangement events. Local free volumes are also found to correlate with particle rearrangements at extreme values, although the ability to identify relaxation sites is substantially lower than S2. Our experiments provide an efficient structural identifier for the fragile regions in glasses and highlight the important role of structural correlations in the physics of glasses.

  2. Structures of Local Rearrangements in Soft Colloidal Glasses.

    PubMed

    Yang, Xiunan; Liu, Rui; Yang, Mingcheng; Wang, Wei-Hua; Chen, Ke

    2016-06-10

    We image local structural rearrangements in soft colloidal glasses under small periodic perturbations induced by thermal cycling. Local structural entropy S_{2} positively correlates with observed rearrangements in colloidal glasses. The high S_{2} values of the rearranging clusters in glasses indicate that fragile regions in glasses are structurally less correlated, similar to structural defects in crystalline solids. Slow-evolving high S_{2} spots are capable of predicting local rearrangements long before the relaxations occur, while fluctuation-created high S_{2} spots best correlate with local deformations right before the rearrangement events. Local free volumes are also found to correlate with particle rearrangements at extreme values, although the ability to identify relaxation sites is substantially lower than S_{2}. Our experiments provide an efficient structural identifier for the fragile regions in glasses and highlight the important role of structural correlations in the physics of glasses. PMID:27341261

  3. The Stereochemical Course of the α-Hydroxyphosphonate–Phosphate Rearrangement

    PubMed Central

    Pallitsch, Katharina; Roller, Alexander; Hammerschmidt, Friedrich

    2015-01-01

    The phosphonate–phosphate rearrangement is an isomerisation of α-hydroxyphosphonates bearing electron-withdrawing substituents at the α-carbon atom. We studied the stereochemical course of this rearrangement with respect to phosphorus. A set of four diastereomeric α-hydroxyphosphonates was prepared by a Pudovik reaction from two diastereomeric cyclic phosphites. The hydroxyphosphonates were separated and rearranged with Et3N as base. In analogy to trichlorphon, which was the first reported compound undergoing this rearrangement. All four hydroxyphosphonates could be rearranged to 2,2-dichlorovinyl phosphates. Single-crystal X-ray structure analyses of the α-hydroxyphosphonates and the corresponding phosphates allowed us to show that the rearrangement proceeds with retention of configuration on the phosphorus atom. PMID:26059025

  4. Programmed genome rearrangements in the ciliate Oxytricha

    PubMed Central

    Yerlici, V. Talya; Landweber, Laura F.

    2015-01-01

    The ciliate Oxytricha is a microbial eukaryote with two genomes, one of which experiences extensive genome remodeling during development. Each round of conjugation initiates a cascade of events that construct a transcriptionally active somatic genome from a scrambled germline genome, with considerable help from both long and small noncoding RNAs. This process of genome remodeling entails massive DNA deletion and reshuffling of remaining DNA segments to form functional genes from their interrupted and scrambled germline precursors. The use of Oxytricha as a model system provides an opportunity to study an exaggerated form of programmed genome rearrangement. Furthermore, studying the mechanisms that maintain nuclear dimorphism and mediate genome rearrangement has demonstrated a surprising plasticity and diversity of non-coding RNA pathways, with new roles that go beyond conventional gene silencing. Another aspect of ciliate genetics is their unorthodox patterns of RNA-mediated, epigenetic inheritance, that rival Mendelian inheritance. This review takes the reader through the key experiments in a model eukaryote that led to fundamental discoveries in RNA biology and pushes the biological limits of DNA processing. PMID:26104449

  5. Exceptional complex chromosomal rearrangements in three generations.

    PubMed

    Kartapradja, Hannie; Marzuki, Nanis Sacharina; Pertile, Mark D; Francis, David; Suciati, Lita Putri; Anggaratri, Helena Woro; Ambarwati, Debby Dwi; Idris, Firman Prathama; Lesmana, Harry; Trimarsanto, Hidayat; Paramayuda, Chrysantine; Harahap, Alida Roswita

    2015-01-01

    We report an exceptional complex chromosomal rearrangement (CCR) found in three individuals in a family that involves 4 chromosomes with 5 breakpoints. The CCR was ascertained in a phenotypically abnormal newborn with additional chromosomal material on the short arm of chromosome 4. Maternal karyotyping indicated that the mother carried an apparently balanced CCR involving chromosomes 4, 6, 11, and 18. Maternal transmission of the derivative chromosome 4 resulted in partial trisomy for chromosomes 6q and 18q and a partial monosomy of chromosome 4p in the proband. Further family studies found that the maternal grandmother carried the same apparently balanced CCR as the proband's mother, which was confirmed using the whole chromosome painting (WCP) FISH. High resolution whole genome microarray analysis of DNA from the proband's mother found no evidence for copy number imbalance in the vicinity of the CCR translocation breakpoints, or elsewhere in the genome, providing evidence that the mother's and grandmother's CCRs were balanced at a molecular level. This structural rearrangement can be categorized as an exceptional CCR due to its complexity and is a rare example of an exceptional CCR being transmitted in balanced and/or unbalanced form across three generations. PMID:25722897

  6. Exceptional Complex Chromosomal Rearrangements in Three Generations

    PubMed Central

    Kartapradja, Hannie; Marzuki, Nanis Sacharina; Pertile, Mark D.; Francis, David; Suciati, Lita Putri; Anggaratri, Helena Woro; Ambarwati, Debby Dwi; Idris, Firman Prathama; Lesmana, Harry; Trimarsanto, Hidayat; Paramayuda, Chrysantine; Harahap, Alida Roswita

    2015-01-01

    We report an exceptional complex chromosomal rearrangement (CCR) found in three individuals in a family that involves 4 chromosomes with 5 breakpoints. The CCR was ascertained in a phenotypically abnormal newborn with additional chromosomal material on the short arm of chromosome 4. Maternal karyotyping indicated that the mother carried an apparently balanced CCR involving chromosomes 4, 6, 11, and 18. Maternal transmission of the derivative chromosome 4 resulted in partial trisomy for chromosomes 6q and 18q and a partial monosomy of chromosome 4p in the proband. Further family studies found that the maternal grandmother carried the same apparently balanced CCR as the proband's mother, which was confirmed using the whole chromosome painting (WCP) FISH. High resolution whole genome microarray analysis of DNA from the proband's mother found no evidence for copy number imbalance in the vicinity of the CCR translocation breakpoints, or elsewhere in the genome, providing evidence that the mother's and grandmother's CCRs were balanced at a molecular level. This structural rearrangement can be categorized as an exceptional CCR due to its complexity and is a rare example of an exceptional CCR being transmitted in balanced and/or unbalanced form across three generations. PMID:25722897

  7. TERT rearrangements are frequent in neuroblastoma and identify aggressive tumors.

    PubMed

    Valentijn, Linda J; Koster, Jan; Zwijnenburg, Danny A; Hasselt, Nancy E; van Sluis, Peter; Volckmann, Richard; van Noesel, Max M; George, Rani E; Tytgat, Godelieve A M; Molenaar, Jan J; Versteeg, Rogier

    2015-12-01

    Whole-genome sequencing detected structural rearrangements of TERT in 17 of 75 high-stage neuroblastomas, with five cases resulting from chromothripsis. Rearrangements were associated with increased TERT expression and targeted regions immediately up- and downstream of TERT, positioning a super-enhancer close to the breakpoints in seven cases. TERT rearrangements (23%), ATRX deletions (11%) and MYCN amplifications (37%) identify three almost non-overlapping groups of high-stage neuroblastoma, each associated with very poor prognosis. PMID:26523776

  8. Dynamic behavior of rearranging carbocations – implications for terpene biosynthesis

    PubMed Central

    Hare, Stephanie R

    2016-01-01

    Summary This review describes unexpected dynamical behaviors of rearranging carbocations and the modern computational methods used to elucidate these aspects of reaction mechanisms. Unique potential energy surface topologies associated with these rearrangements have been discovered in recent years that are not only of fundamental interest, but also provide insight into the way Nature manipulates chemical space to accomplish specific chemical transformations. Cautions for analyzing both experimental and theoretical data on carbocation rearrangements are included throughout. PMID:27340434

  9. Dispersion-Energy-Driven Wagner–Meerwein Rearrangements in Oligosilanes

    PubMed Central

    2016-01-01

    The installation of structural complex oligosilanes from linear starting materials by Lewis acid induced skeletal rearrangement reactions was studied under stable ion conditions. The produced cations were fully characterized by multinuclear NMR spectroscopy at low temperature, and the reaction course was studied by substitution experiments. The results of density functional theory calculations indicate the decisive role of attractive dispersion forces between neighboring trimethylsilyl groups for product formation in these rearrangement reactions. These attractive dispersion interactions control the course of Wagner–Meerwein rearrangements in oligosilanes, in contrast to the classical rearrangement in hydrocarbon systems, which are dominated by electronic substituent effects such as resonance and hyperconjugation. PMID:27195490

  10. Dispersion-Energy-Driven Wagner-Meerwein Rearrangements in Oligosilanes.

    PubMed

    Albers, Lena; Rathjen, Saskia; Baumgartner, Judith; Marschner, Christoph; Müller, Thomas

    2016-06-01

    The installation of structural complex oligosilanes from linear starting materials by Lewis acid induced skeletal rearrangement reactions was studied under stable ion conditions. The produced cations were fully characterized by multinuclear NMR spectroscopy at low temperature, and the reaction course was studied by substitution experiments. The results of density functional theory calculations indicate the decisive role of attractive dispersion forces between neighboring trimethylsilyl groups for product formation in these rearrangement reactions. These attractive dispersion interactions control the course of Wagner-Meerwein rearrangements in oligosilanes, in contrast to the classical rearrangement in hydrocarbon systems, which are dominated by electronic substituent effects such as resonance and hyperconjugation. PMID:27195490

  11. Photoinduced molecular dissociation and photoinduced recombination mediated by superfluid helium nanodroplets.

    PubMed

    Kautsch, Andreas; Koch, Markus; Ernst, Wolfgang E

    2015-05-14

    We have investigated photoinduced chemical reaction dynamics of cold, isolated Cr2 molecules in helium nanodroplets (HeN), exploiting the quantum state specific spatial separation of solvated and surface locations on the droplet. The molecules are excited to achieve dissociation to a ground state (a(7)S3) and a metastable state (a(5)S2) atom. State specific spatial separation, in combination with efficient translational cooling to avoid ejection, causes the ground state atom to be solvated inside the droplet while the metastable atom migrates to the surface. A barrier between the two reactants formed by the HeN prevents recombination. We apply a resonance-enhanced multiphoton ionization scheme including the y(5)P°(1,2,3) <-- a(5)S(2) transition of the surface atom as well as a two-laser scheme including the y(7)P°(2,3,4) <-- a(7)S(3) transition of the solvated atom in order to verify the locations and separation of the dissociation products. Furthermore, ionization of the a(5)S2 surface atom triggers solvation followed by geminate recombination with the a(7)S3 atom, which is verified by the detection of Cr2(+) molecular ions. For small Cr clusters, our results indicate that they may be composed of chromium dimers that exhibit the same dissociation behavior. PMID:25894482

  12. Common Gene Rearrangements in Prostate Cancer

    PubMed Central

    Rubin, Mark A.; Maher, Christopher A.; Chinnaiyan, Arul M.

    2011-01-01

    Prostate cancer is a common heterogeneous disease, and most patients diagnosed in the post prostate-specific antigen (PSA) era present with clinically localized disease, the majority of which do well regardless of treatment regimen undertaken. Overall, those with advanced prostate cancer at time of diagnosis do poorly after androgen withdrawal therapy. Understanding the biologic underpinning of prostate cancer is necessary to best determine the risk of disease progression and would be advantageous for the development of novel therapeutic approaches to impede or prevent disease. This review focuses on the recently identified common ETS and non-ETS gene rearrangements in prostate cancer. Although multiple molecular alterations have been detected in prostate cancer, a detailed understanding of gene fusion prostate cancer should help explain the clinical and biologic diversity, providing a rationale for a molecular subclassification of the disease. PMID:21859993

  13. Minimal distortion pathways in polyhedral rearrangements.

    PubMed

    Casanova, David; Cirera, Jordi; Llunell, Miquel; Alemany, Pere; Avnir, David; Alvarez, Santiago

    2004-02-18

    A definition of minimum distortion paths between two polyhedra in terms of continuous shape measures (CShM) is presented. A general analytical expression deduced for such pathways makes use of one parameter, the minimum distortion constant, that can be easily obtained through the CShM methodology and is herein tabulated for pairs of polyhedra having four to eight vertexes. The work presented here also allows us to obtain representative model molecular structures along the interconversion pathways. Several commonly used polytopal rearrangement pathways are shown to be in fact minimum distortion pathways: the spread path leading from the tetrahedron to the square, the Berry pseudorotation that interconverts a square pyramid and a trigonal bipyramid, and the Bailar twist for the interconversion of the octahedron and the trigonal prism. Examples of applications to the analysis of the stereochemistries of several families of metal complexes are presented. PMID:14871107

  14. Cytoplasmic rearrangements associated with amphibian egg symmetrization

    NASA Technical Reports Server (NTRS)

    Malacinski, G. M.

    1984-01-01

    Cytoplasmic rearrangements which follow fertilization were mentioned in normal and inverted eggs. A set of yolk compartments was resolved by cytological analyses of both normally oriented and inverted eggs. Those compartments were characterized by their yolk platelet compositions and movement during egg inversion. It is found that during egg inversion the yolk compartments shift minor cytoplasmic compartments which line the egg cortex. Those yolk mass shifts occurred only after the inverted egg was activated. The direction of shift of the major yolk components, rather than the sperm entrance site, determines the dorsal/ventral polarity of the inverted egg. Among different spawnings the rate of shift varied. Eggs that displayed the fastest rate of shift exhibited the highest frequency of developmental abnormalities during organogenesis. Interpretation of novel observations on cytoplasmic organization provide criticism of some earlier models. A new density compartment model is presented as a coherent way to view the organization of the egg cytoplasm and the development of bilateral symmetry.

  15. New progress in snake mitochondrial gene rearrangement.

    PubMed

    Chen, Nian; Zhao, Shujin

    2009-08-01

    To further understand the evolution of snake mitochondrial genomes, the complete mitochondrial DNA (mtDNA) sequences were determined for representative species from two snake families: the Many-banded krait, the Banded krait, the Chinese cobra, the King cobra, the Hundred-pace viper, the Short-tailed mamushi, and the Chain viper. Thirteen protein-coding genes, 22-23 tRNA genes, 2 rRNA genes, and 2 control regions were identified in these mtDNAs. Duplication of the control region and translocation of the tRNAPro gene were two notable features of the snake mtDNAs. These results from the gene rearrangement comparisons confirm the correctness of traditional classification schemes and validate the utility of comparing complete mtDNA sequences for snake phylogeny reconstruction. PMID:19479623

  16. Tomographic phase analysis to detect the site of accessory conduction pathway in Wolff-Parkinson-White syndrome

    SciTech Connect

    Nakajima, K.; Bunko, H.; Tada, A.; Tonami, N.; Taki, J.; Nanbu, I.; Hisada, K.; Misaki, T.; Iwa, T.

    1984-01-01

    Phase analysis has been applied to Wolff-Parkinson-White syndrome (WPW) to detect the site of accessory conduction pathway (ACP); however, there was a limitation to estimate the precise location of ACP by planar phase analysis. In this study, the authors applied phase analysis to gated blood pool tomography. Twelve patients with WPW who underwent epicardial mapping and surgical division of ACP were studied by both of gated emission computed tomography (GECT) and routine gated blood pool study (GBPS). The GBPS was performed with Tc-99m red blood cells in multiple projections; modified left anterior oblique, right anterior oblique and/or left lateral views. In GECT, short axial, horizontal and vertical long axial blood pool images were reconstructed. Phase analysis was performed using fundamental frequency of the Fourier transform in both GECT and GBPS images, and abnormal initial contractions on both the planar and tomographic phase analysis were compared with the location of surgically confirmed ACPs. In planar phase analysis, abnormal initial phase was identified in 7 out of 12 (58%) patients, while in tomographic phase analysis, the localization of ACP was predicted in 11 out of 12 (92%) patients. Tomographic phase analysis is superior to planar phase images in 8 out of 12 patients to estimate the location of ACP. Phase analysis by GECT can avoid overlap of blood pool in cardiac chambers and has advantage to identify the propagation of phase three-dimensionally. Tomographic phase analysis is a good adjunctive method for patients with WPW to estimate the site of ACP.

  17. Relation of syncope in young patients with Wolff-Parkinson-White syndrome to rapid ventricular response during atrial fibrillation.

    PubMed

    Paul, T; Guccione, P; Garson, A

    1990-02-01

    Syncope in patients due to Wolff-Parkinson-White (WPW) syndrome may be related either to a rapid rate of supraventricular tachycardia or to rapid ventricular response over the accessory pathway during atrial fibrillation (AF). From 1982 to 1987, 74 patients less than or equal to 25 years old (mean age 12.6 years) with WPW syndrome on electrocardiogram underwent electrophysiologic study. Of the 74 patients, 14 (19%) had a history of syncope. During electrophysiologic study 9 of 14 patients with syncope had sustained (greater than 5 minutes or requiring termination due to hypotension) AF. Of the remaining 5 patients, 3 had inducible nonsustained AF and 2 had no AF. None of the 60 patients without syncope developed sustained AF; 34 had nonsustained and 26 had no AF. Occurrence of sustained AF had a sensitivity of 64% and specificity of 100% for history of syncope. All patients with syncope and AF (12) had a short RR interval between 2 consecutive preexcited QRS complexes during AF at less than or equal to 220 ms, in contrast to 9 of 34 patients without syncope (p less than 0.001, sensitivity 100%, specificity 74%). No patient with a short RR interval between 2 consecutive preexcited QRS complexes during AF of greater than 220 ms had a history of syncope. Thus, in these young patients with WPW syndrome, occurrence of AF with a rapid ventricular response during electrophysiologic study correlated well with a history of syncope and may be the cause of syncope in most patients. Electrophysiologic study may be helpful in identification of young patients with WPW at risk for syncope. PMID:2301260

  18. Exercise testing and thallium-201 myocardial perfusion scintigraphy in the clinical evaluation of patients with Wolff Parkinson White syndrome

    SciTech Connect

    Poyatos, M.E.; Suarez, L.; Lerman, J.; Guibourg, H.; Camps, J.; Perosio, A.

    1986-10-01

    In 58 patients with Wolff Parkinson White syndrome (WPW), we performed exercise stress testing in order to investigate the incidence of normalization of the auriculo-ventricular conduction and the ST-segment changes. For a more accurate evaluation of the latter, exercise and redistribution radionuclide images with Thallium-201 were obtained in 18 cases. Forty-nine had type A and nine had type B of WPW. Forty-eight had permanent, four had alternant and six had no pre-excitation (PE) when they started the test. Mean maximal functional capacity, mean maximal heart rate and mean maximal double product were not different when compared to an age-matched control group. Of the 48 patients who began the test with PE, in 23 (48%) it disappeared while PE persisted in 25 (52%). In 16 cases the disappearance of the PE was sudden and in seven it was progressive. Pre-excitation persisted in 39.5% of patients with type A and in 88.8% with type B (p less than 0.01). ST-segment depression was observed in 76.6% of patients with PE and in 28.6% of cases without PE (p less than 0.01). ST-segment depression occurred in 44.8% of patients with type A and in 100% of cases with type B (p less than 0.05). Transient abnormal Thallium-201 scans were observed in 62.5% of patients without PE and in 20% with PE. No patients showed exertional arrhythmias. This study suggests the possibility of measuring the duration of the refractory period of the accessory pathway in those patients n which the PE disappears suddenly, at a given heart rate.

  19. [Usefulness of the thoracic circle in localizing the pre-excitation zone in Wolff-Parkinson-White syndrome].

    PubMed

    Iturralde, P; de Micheli, A; Romero, L; Hernández, D; Méndez, A; Gutiérrez, A; Colin, L; González Hermosillo, J A

    1989-01-01

    In this study thoracic circle lead electrocardiogram were recorded during sinus rhythm in 50 patients with Wolff Parkinson White Syndrome. We analyzed: delta wave polarity, QRS axis in the frontal plane, ventricular preexcitation, the pattern of precordial R wave transition and QRS morphology in the unipolar leads, also concordance between electrocardiographic patterns and the site of the accessory pathway determined during electrophysiological study. Electrocardiograms from patients with left lateral sites showed negative delta waves in leads LI or a VL, V7 to V9, positive delta waves in V3R to V9R, a normal QRS axis and early precordial R wave transition (20 of 23 patients). Left posterior sites manifested negative Delta waves in L3, a VF, V7 to V9, V7R to V9R and a prominent R wave in V1 (4 of 5 patients). Left posteroparaseptal sites had the same pattern plus negative delta waves in L2, a superior QRS axis, and RS or Rs morphology in V1 (3 of 3 patients). Right posteroparaseptal sites had negative delta waves in L2, L3, a VF, V3R to V9R, positive delta waves in V7 to V9, a superior QRS axis and an R greater than S in V1 (10 of 11 patients). Right free wall locations manifested negative delta waves in L3, a VR, V3R to V9R, positive delta waves in V7 to V9, a normal QRS axis and R wave transition in V3 to V5 with QS morphology since V3R to V9R (6 of 7 patients).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2624501

  20. Dynamical properties of nucleus boundaries in photoinduced structural change

    NASA Astrophysics Data System (ADS)

    Ishida, Kunio; Nasu, Keiichiro

    2014-01-01

    Dynamics of the boundaries of photoinduced nuclei in electron-phonon systems is theoretically studied. By regarding the spatial distribution of the excited electronic state population as a geometric pattern, we applied the multifractal analysis to it and calculated the temporal behavior of the fractal dimension f(α) as a function of the Lipschitz-Hölder exponent α, which is an appropriate method for understanding the cooperative relaxation process of photoexcited states. We found that the incubation period observed in various types of photoinduced cooperative phenomena corresponds to the formation of embryonic nuclei which is driven by nonadiabatic/adiabatic transition between electronic states during the relaxation of the Franck-Condon state.

  1. The time of a photoinduced spin-Peierls phase transition

    SciTech Connect

    Semenov, A. L.

    2015-02-15

    The time τ of the spin-Peierls phase transition is analyzed theoretically as a function of the duration τ{sub p} of the exciting light pulse and the average number x{sub 0} of absorbed photons per magnetic ion after the transmission of the pulse. It is shown that the phase transition occurs at x{sub 0} > x{sub c}. The critical value x{sub c} is determined as a function of the duration τ{sub p} of the light pulse. A photoinduced variation in the optical reflection coefficient R is calculated as a function of time t. The results of calculation are compared with experimental data on ultrafast photoinduced melting of the low-temperature spin-Peierls phase into potassium tetracyanoquinodimethan (K-TCNQ)

  2. Dynamics of photoinduced dichroism and birefringence in optically thick azopolymers

    SciTech Connect

    Ponomarev, Yu V; Ivanov, Yu V; Rumyantsev, Yu A; Gromchenko, A A

    2009-01-31

    Dynamics of photoinduced dichroism and birefringence have been studied experimentally and theoretically (with the help of the Dumont model) by using some comb-shaped azopolymers. It is shown that the dynamics of trans-isomer concentration and their angular distribution anisotropy can be restored from the experimentally found dichroism dynamics, with the concentration and anisotropy being averaged over the thickness for optically thick samples. At the initial stage of photoinduced anisotropy when the active role of the polymer matrix can be neglected, the experimental time dependence of dichroism is shown to comply well with the Dumont model even if the orientation memory is neglected, provided that only a part of trans-isomers participates in trans-isomerisation. (nonlinear optical phenomena)

  3. Photo-induced anisotropic photoelectric response in oriented bacteriorhodopsin films

    NASA Astrophysics Data System (ADS)

    Xu, J.; Bhattacharya, P.; Váró, G.

    2003-06-01

    The photo-induced anisotropic properties of the chromophore protein bacteriorhodopsin (bR) are of interest for possible applications in optical image processing and spatial filtering. Here we report experimental results on the photo-induced anisotropic photoelectric response of dried oriented bR films. A polarization dependent photovoltage is measured across an ITO/bR/ITO photodetector. The anisotropy is introduced by a 632.8 nm linearly polarized pump beam and is detected with a 594.1 nm polarized probe beam. The influence of the pump light intensity on the photovoltage anisotropy has also been investigated. A model, based on the polarization dependent photoselection of the bR molecules reasonably explains the behavior of the measured data. The observed effect can be used to construct a polarization sensitive bR-based bio-photoreceiver.

  4. Photoinduced translational molecular mobility in solid nanostructured azo dye films

    SciTech Connect

    Ezhov, A A; Kozenkov, V M; Magnitskii, Sergey A; Nagorskii, Nikolay M; Panov, Vladimir I

    2011-11-30

    A new mechanism controlling the molecular motion in thin azo-containing films during a photoinduced change in the surface nanorelief is found. It is shown experimentally that exposure of a solid AD-1 azo dye, deposited on a glass substrate, to incoherent linearly polarised light leads to formation of nanostructures with a characteristic size of 200 nm, which are similar to droplets of melt of this dye on the same substrate. It is shown that photoinduced mass transport in a solid AD-1 azo dye film can be explained by the mobility of molecules related to their trans-cis-photoisomerisation, which leads to film softening with subsequent formation of spherical protrusions under surface tension forces.

  5. Photoinduced 1,2,3,4-tetrahydropyridine ring conversions.

    PubMed

    Turovska, Baiba; Lund, Henning; Lūsis, Viesturs; Lielpētere, Anna; Liepiņš, Edvards; Beljakovs, Sergejs; Goba, Inguna; Stradiņš, Jānis

    2015-01-01

    Stable heterocyclic hydroperoxide can be easily prepared as a product of fast oxidation of a 1,2,3,4-tetrahydropyridine by (3)O2 if the solution is exposed to sunlight. The driving force for the photoinduced electron transfer is calculated from electrochemical and spectroscopic data. The outcome of the reaction depends on the light intensity and the concentration of O2. In the solid state the heterocyclic hydroperoxide is stable; in solution it is involved in further reactions. PMID:26664638

  6. Photoinduced 1,2,3,4-tetrahydropyridine ring conversions

    PubMed Central

    Lund, Henning; Lūsis, Viesturs; Lielpētere, Anna; Liepiņš, Edvards; Beljakovs, Sergejs; Goba, Inguna; Stradiņš, Jānis

    2015-01-01

    Summary Stable heterocyclic hydroperoxide can be easily prepared as a product of fast oxidation of a 1,2,3,4-tetrahydropyridine by 3O2 if the solution is exposed to sunlight. The driving force for the photoinduced electron transfer is calculated from electrochemical and spectroscopic data. The outcome of the reaction depends on the light intensity and the concentration of O2. In the solid state the heterocyclic hydroperoxide is stable; in solution it is involved in further reactions. PMID:26664638

  7. Uniparental disomy analysis in carriers of balanced chromosome rearrangements

    SciTech Connect

    May, K.M.; Pettay, D.; Muralidharan, K.

    1994-09-01

    Although most individuals who carry a balanced familial chromosome rearrangement are phenotypically normal, those who are clinically abnormal raise the question of whether or not the rearrangement plays a causative role. One possible mechanism involves meiotic segregation of a normal homolog along with the rearranged chromosome(s) such that a trisomic conception occurs. Subsequent loss by mitotic nondisjunction of the structurally normal chromosome contributed by the non-carrier parent would then result in uniparental disomy (UPD) in a conceptus carrying a balanced rearrangement. UPD for chromosomes 14 and 15 has been demonstrated in several clinically abnormal individuals who carry a familial Robertsonian translocation. We have extended this type of analysis to include other forms of balanced chromosome rearrangements. We report the results of UPD analysis of 14 families who have a phenotypically abnormal child with an apparently balanced rearrangement. The series includes 4 reciprocal translocations, 4 Robertsonian translocations, 2 X;autosome translocations, and 4 inversions. High resolution chromosomes were used to compare breakpoints between parent and offspring to exclude the possibility of further rearrangements. Parental origin of the chromosome(s) involved was determined by DNA polymorphism analysis using PCR or Southern blotting techniques. We found no evidence of UPD in any of the 14 cases. Our data suggest that UPD is not a common explanation for phenotypically abnormal carriers of balanced chromosome rearrangements.

  8. Enantioselective Claisen rearrangements with a hydrogen-bond donor catalyst.

    PubMed

    Uyeda, Christopher; Jacobsen, Eric N

    2008-07-23

    N,N'-Diphenylguanidinium ion associated with the noncoordinating BArF counterion is shown to be an effective catalyst for the [3,3]-sigmatropic rearrangement of a variety of substituted allyl vinyl ethers. Highly enantioselective catalytic Claisen rearrangements of ester-substituted allyl vinyl ethers are then documented using a new C2-symmetric guanidinium ion derivative. PMID:18576616

  9. Plasmonic, excitonic and exciton-plasmonic photoinduced nanocomposites

    NASA Astrophysics Data System (ADS)

    Bityurin, N.; Ermolaev, N.; Smirnov, A. A.; Afanasiev, A.; Agareva, N.; Koryukina, T.; Bredikhin, V.; Kamensky, V.; Pikulin, A.; Sapogova, N.

    2016-03-01

    UV irradiation of materials consisting of a polymer matrix that possesses precursors of different kinds can result in creation of nanoparticles within the irradiated domains. Such photoinduced nanocomposites are promising for photonic applications due to the strong alteration of their optical properties compared to initial non-irradiated materials. We report our results on the synthesis and investigation of plasmonic, excitonic and exciton-plasmonic photoinduced nanocomposites. Plasmonic nanocomposites contain metal nanoparticles of noble metals with a pronounced plasmon resonance. Excitonic nanocomposites possess semiconductor nanoclusters (quantum dots). We consider the CdS-Au pair because the luminescent band of CdS nanoparticles enters the plasmon resonance band of gold nanoparticles. The obtaining of such particles within the same composite materials is promising for the creation of media with exciton-plasmon resonance. We demonstrate that it is possible to choose appropriate precursor species to obtain the initially transparent poly(methyl methacrylate) (PMMA) films containing both types of these molecules either separately or together. Proper irradiation of these materials by a light-emitting diode operating at the wavelength of 365 nm provides material alteration demonstrating light-induced optical absorption and photoluminescent properties typical for the corresponding nanoparticles. Thus, an exciton-plasmonic photoinduced nanocomposite is obtained. It is important that here we use the precursors that are different from those usually employed.

  10. Smartphones in the Operating Room: Distraction or Diagnostic Aid? A Case of Newly Diagnosed Wolff-Parkinson White in a Pediatric Patient Having Bronchoscopy Under General Anesthesia.

    PubMed

    Esenther, Brandon; Ko, Riva

    2015-08-01

    A 4-year-old boy presented for elective bronchoscopy after years of pharmacologically unresponsive reactive airway disease that limited physical activity. After mask induction with nitrous oxide and sevoflurane, the patient was noted to be intermittently in a hemodynamically stable tachyarrhythmia. The anesthesia machine, though equipped with electrocardiogram (ECG) recording capabilities, malfunctioned during the case and was not able to print a rhythm strip. As a substitute, a smartphone picture and video were recorded. In the recovery room, initial 12-lead ECG showed sinus tachycardia. Shortly after, a presumptive diagnosis of Wolff-Parkinson White was given upon review of the smartphone recordings by the pediatric cardiologist on service. Twelve lead ECG was repeated which showed intermittent Wolff-Parkinson White. This case highlights 2 points. First, any prolonged or sustained pediatric dysrhythmia revealed during anesthesia warrants further investigation and should not be assumed secondary to an anesthetic drug. Second, ubiquitous smartphones are an excellent tool for capturing data that the monitor is unable to capture. PMID:26230306

  11. Ants cushion applied stress by active rearrangements

    NASA Astrophysics Data System (ADS)

    Liu, Zhongyang; Hyatt, John; Mlot, Nathan; Gerov, Michael; Fernandez-Nieves, Alberto; Hu, David

    2013-11-01

    Fire ants, Solenopsis invicta, link their bodies together to form waterproof rafts, which in turn drip, spread, and coagulate, demonstrating properties of an active material that can change state from a liquid to a solid. This soft-matter phase transition is important when the raft interacts with environmental forces such as raindrops and crashing waves. We study this active behavior through plate-on-plate rheology on the ants, extracting the active components by comparison with the rheological behavior of a collection of dead ants. In controlled shear tests, both and live and dead ants show properties of a non-Newtonian fluid, specifically, shear-thinning behavior. In oscillatory tests, live ants exhibit a rare behavior in which their storage modulus (G') and loss modulus (G'') have approximately the same value over three orders magnitudes of frequency and two orders of magnitude of strain, indicating the ants are neither fluid nor solid. In comparison, dead ants are more solid-like, with a storage modulus twice as large as their loss modulus. This striking active behavior arises from rearrangement of their bodies and storage and dissipation of energy with the ants' muscles.

  12. Photoinduced surface reactions on TiO{sub 2} and SrTiO{sub 3} films: Photocatalytic oxidation and photoinduced hydrophilicity

    SciTech Connect

    Miyauchi, Masahiro; Nakajima, Akira; Fujishima, Akira; Hashimoto, Kazuhito; Watanabe, Toshiya

    2000-01-01

    In the present study, the authors have evaluated photocatalytic activities and photoinduced wettabilities for TiO{sub 2} and SrTiO{sub 3} films. Although both types of films had almost the same photocatalytic oxidation activity, photoinduced wettabilities of these films showed different phenomena. The photoinduced hydrophilicity peculiar to TiO{sub 2} is not caused by the photocatalytic oxidation of organic compounds adsorbed on the surface. The highly hydrophilic surface of TiO{sub 2} is ascribed to photogenerated Ti{sup 3+} defect sites that are favorable for dissociative water absorption. The yield of this photoinduced hydrophilic reaction is not clear at the present time. It is noted that this reaction involves a surface structural change, which should not require a high quantum efficiency as compared to conventional photocatalytic oxidation.

  13. Photoinduced dichroism in Bacteriorhodopsin and its application to optical computing and information processing

    NASA Astrophysics Data System (ADS)

    Denis, Kevin; Aranda, Francisco J.

    1998-03-01

    The intensity dependence of the photoinduced dichroism in Bacteriorhodopsin (bR) films has potential application in optical image processing and optical computing. Under the illumination of linearly polarized actinic light of 570 nm wavelength, the photoinduced dichroism in a Bacteriorhodopsin film induces polarization rotation for a probe beam of the same wavelength. This behavior is a function of the life time of the M state in the Bacteriorhodopsin photocycle. We studied the dependence of the photoinduced dichroism on the pH environment in which the bR molecules are and on genetic mutation by replacement of the Aspartic amino acid in position 96 by Asparagine. The photoinduced probe polarization rotation can be exploited for optical Fourier processing and logic operations. The intensity dependence of the photoinduced dichroism in the different films has important implications on the applications for which they are suitable.

  14. Photoinduced "stick-slip" on superhydrophilic semiconductor surfaces.

    PubMed

    Denison, Kieth R; Boxall, Colin

    2007-04-10

    Transparent mesoporous TiO2 (M-TiO2) thin films were prepared on quartz via a reverse micelle, sol-gel, spin-coating technique. Films were characterized by atomic force microscopy (AFM) and Raman and UV-vis spectroscopies and were found to be mostly anatase with low surface roughness (Rt approximately 5 nm). The time dependence of film photoinduced superhydrophilicity (PISH) was measured by observation of the spreading of a sessile water drop using a new, continuous measurement technique wherein the drop was first applied to the semiconductor surface and then was filmed while it and the underlying substrate were illuminated by 315 nm ultraband gap light. Results obtained at 100% relative humidity (RH) at 293 K showed that drops on M-TiO2 surfaces exhibited a photoinduced "stick-slip" behavior, the first time such an effect has been observed. The thermodynamic driving force for this photoinduced stick-slip was the departure of the system from capillary equilibrium as, with increasing illumination time, the concentration of surface Ti-OH groups increased and the equilibrium contact angle of the drop, theta0, decreased. A simple theoretical description of photoinduced stick-slip is derived and is used to calculate a value of the potential energy barrier associated with surface inhomogeneities that oppose onset of movement of the triple line, U = 6.63 x 10(-6) J m(-1). This is the first time that U has been quantified for a surface with photoinduced superhydrophilicity. Triple line retreat measurements on an evaporating drop on M-TiO2 in the dark, RH = 60%, T = 293 K, gave a value of U = 9.4 x 10(-6) J m(-1), indicating that U decreases upon UV illumination and that U in the light is primarily associated with inhomogeneities that are unaffected by an increase in the surface Ti-OH population, such as the physical roughness of the surface. In the dark evaporation experiment, the drop was found to retreat with an areal velocity of 1.48 x 10(-8) m2 s(-1). However, under UV

  15. Polyion complex vesicles for photoinduced intracellular delivery of amphiphilic photosensitizer.

    PubMed

    Chen, Huabing; Xiao, Ling; Anraku, Yasutaka; Mi, Peng; Liu, Xueying; Cabral, Horacio; Inoue, Aki; Nomoto, Takahiro; Kishimura, Akihiro; Nishiyama, Nobuhiro; Kataoka, Kazunori

    2014-01-01

    Polymer vesicles formed by a pair of oppositely charged poly(ethylene glycol) (PEG)-based block aniomer and homocatiomer, termed "PICsomes", have tunable size, and are characterized by unique semipermeable property due to the flexible and tunable hydrophilicity of polyion complex (PIC) membranes. The PICsomes can encapsulate a variety of molecules in an inner aqueous phase just by a simple vortex mixing of solution, expecting their utility as nanocontainers of substances with biomedical interests. Here, we report on a new functionality of the PICsomes: photoinduced release of photoactive agents for intracellular drug delivery. A potent photosensitizer, Al(III) phthalocyanine chloride disulfonic acid (AlPcS2a), was efficiently incorporated into the PICsomes (11%(w/w)), and its quick release was induced by photoirradiation possibly due to the photochemical damage of the PIC membranes. The combination of a high-resolution fluorescent confocal microscopy and a lysosome membrane-specific staining method revealed that such photoinduced release of AlPcS2a occurred even in the lysosomes of living cells after endocytic internalization. Simultaneously, the released AlPcS2a photochemically affected the integrity of the lysosomal membranes, leading to the translocation of AlPcS2a and PICsomes themselves to the cytoplasm. Consequently, the AlPcS2a-encapsulated PICsomes (AlPcS2a-PICsomes) exhibited appreciably stronger photocytotoxicity compared with free AlPcS2a alone. Thus, the AlPcS2a-PICsomes have promising feasibility for the photodynamic therapy or the photoinduced cytoplasmic delivery of therapeutic molecules. PMID:24283288

  16. : a database of ciliate genome rearrangements

    PubMed Central

    Burns, Jonathan; Kukushkin, Denys; Lindblad, Kelsi; Chen, Xiao; Jonoska, Nataša; Landweber, Laura F.

    2016-01-01

    Ciliated protists exhibit nuclear dimorphism through the presence of somatic macronuclei (MAC) and germline micronuclei (MIC). In some ciliates, DNA from precursor segments in the MIC genome rearranges to form transcriptionally active genes in the mature MAC genome, making these ciliates model organisms to study the process of somatic genome rearrangement. Similar broad scale, somatic rearrangement events occur in many eukaryotic cells and tumors. The (http://oxytricha.princeton.edu/mds_ies_db) is a database of genome recombination and rearrangement annotations, and it provides tools for visualization and comparative analysis of precursor and product genomes. The database currently contains annotations for two completely sequenced ciliate genomes: Oxytricha trifallax and Tetrahymena thermophila. PMID:26586804

  17. Asymmetric Organocatalytic Wittig [2,3]-Rearrangement of Oxindoles.

    PubMed

    Ošeka, Maksim; Kimm, Mariliis; Kaabel, Sandra; Järving, Ivar; Rissanen, Kari; Kanger, Tõnis

    2016-03-18

    A highly enantioselective organocatalytic [2,3]-rearrangement of oxindole derivatives is presented. The reaction was catalyzed by squaramide, and this provides access to 3-hydroxy 3-substituted oxindoles in high enantiomeric purities. PMID:26937554

  18. 2 CFR 200.462 - Rearrangement and reconversion costs.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... rearrangement and alteration of facilities are allowable as indirect costs. Special arrangements and alterations... Agreements OFFICE OF MANAGEMENT AND BUDGET GUIDANCE Reserved UNIFORM ADMINISTRATIVE REQUIREMENTS, COST PRINCIPLES, AND AUDIT REQUIREMENTS FOR FEDERAL AWARDS Cost Principles General Provisions for Selected...

  19. Photoinduced Electron Transfer Based Ion Sensing within an Optical Fiber

    PubMed Central

    Englich, Florian V.; Foo, Tze Cheung; Richardson, Andrew C.; Ebendorff-Heidepriem, Heike; Sumby, Christopher J.; Monro, Tanya M.

    2011-01-01

    We combine suspended-core microstructured optical fibers with the photoinduced electron transfer (PET) effect to demonstrate a new type of fluorescent optical fiber-dip sensing platform for small volume ion detection. A sensor design based on a simple model PET-fluoroionophore system and small core microstructured optical fiber capable of detecting sodium ions is demonstrated. The performance of the dip sensor operating in a high sodium concentration regime (925 ppm Na+) and for lower sodium concentration environments (18.4 ppm Na+) is explored and future approaches to improving the sensor’s signal stability, sensitivity and selectivity are discussed. PMID:22163712

  20. The photoinduced polarization in Kapton-H film

    NASA Astrophysics Data System (ADS)

    Quamara, J. K.; Bhardwaj, R. P.; Sharma, B. L.

    1984-12-01

    The photoinduced polarization in Kapton-H thin film has been studied by analysing the isothermal dark decay characteristics of photo- and dark-polarized specimens for different values of the polarizing parameters. The total polarization induced has been found to increase continuously with polarizing temperature but with polarizing field, it approaches a saturation. The behaviour of dark decay currents for photo and dark polarized identical samples changes with operating temperature. The phenomenon is explained in terms of the shift of electrons and hole demarcation levels under variation of temperature and illumination intensity.

  1. Measurements of photoinduced refractive index changes in bacteriorhodopsin films

    NASA Astrophysics Data System (ADS)

    Banyal, Ravinder Kumar; Raghavendra Prasad, B.

    2007-03-01

    We report the pump--probe measurements of nonlinear refractive index changes in photochromic bacteriorhodopsin films. The photoinduced absorption is caused by pump beam at 532 nm and the accompanying refractive index changes are studied using a probe beam at 633 nm. The proposed technique is based on a convenient and accurate determination of optical path difference using digital interferometry-based local fringe shift. The results are presented for the wild-type as well as genetically modified D96N variant of the bacteriorhodopsin.

  2. Inhomogeneity of photo-induced fat cell lipolysis

    NASA Astrophysics Data System (ADS)

    Doubrovsky, V. A.; Yanina, I. Yu.; Tuchin, V. V.

    2010-10-01

    The effect of optical properties changes of adipose tissue cells in vitro as a result of photoaction was found and investigated. The experimental study of photo-induced post action upon the cells of fat tissue by means of digital microscopy was fulfilled. The computer processing of digital photos obtained gave an opportunity to estimate quantitatively the level of photoaction upon tissue. Optical interpretation of photos obtained proves that the phenomenon observed corresponds to the lipolysis of adipose tissue cells, but without their complete destruction.

  3. Inhomogeneity of photo-induced fat cell lipolysis

    NASA Astrophysics Data System (ADS)

    Doubrovsky, V. A.; Yanina, I. Yu.; Tuchin, V. V.

    2011-03-01

    The effect of optical properties changes of adipose tissue cells in vitro as a result of photoaction was found and investigated. The experimental study of photo-induced post action upon the cells of fat tissue by means of digital microscopy was fulfilled. The computer processing of digital photos obtained gave an opportunity to estimate quantitatively the level of photoaction upon tissue. Optical interpretation of photos obtained proves that the phenomenon observed corresponds to the lipolysis of adipose tissue cells, but without their complete destruction.

  4. Photoinduced absolute negative current in a symmetric molecular electronic bridge

    SciTech Connect

    Prociuk, Alexander; Dunietz, Barry D

    2010-09-28

    The study of current induced by photoradiating a molecular-based device under bias is of fundamental importance to the improvement of photoconductors and photovoltaics. In this technology, electron pumps generate an uphill current that opposes a potential drop and thereby recharges a fuel cell. While the modeled molecular electron pump is completely symmetric, the sign of the photocurrent is solely determined by the existing bias and the nature of photoinduced electronic excitations. The photoradiation induces nonequilibrium population of the electrode-coupled system. The dependence of the photocurrent on electrode coupling, photoradiation field strength, and applied bias are studied at a basic model level.

  5. Ultrafast infrared studies of complex ligand rearrangements in solution

    SciTech Connect

    Payne, Christine K.

    2003-05-31

    The complete description of a chemical reaction in solution depends upon an understanding of the reactive molecule as well as its interactions with the surrounding solvent molecules. Using ultrafast infrared spectroscopy it is possible to observe both the solute-solvent interactions and the rearrangement steps which determine the overall course of a chemical reaction. The topics addressed in these studies focus on reaction mechanisms which require the rearrangement of complex ligands and the spectroscopic techniques necessary for the determination of these mechanisms. Ligand rearrangement is studied by considering two different reaction mechanisms for which the rearrangement of a complex ligand constitutes the most important step of the reaction. The first system concerns the rearrangement of a cyclopentadienyl ring as the response of an organometallic complex to a loss of electron density. This mechanism, commonly referred to as ''ring slip'', is frequently cited to explain reaction mechanisms. However, the ring slipped intermediate is too short-lived to be observed using conventional methods. Using a combination of ultrafast infrared spectroscopy and electronic structure calculations it has been shown that the intermediate exists, but does not form an eighteen-electron intermediate as suggested by traditional molecular orbital models. The second example examines the initial steps of alkyne polymerization. Group 6 (Cr, Mo, W) pentacarbonyl species are generated photolytically and used to catalyze the polymerization of unsaturated hydrocarbons through a series of coordination and rearrangement steps. Observing this reaction on the femto- to millisecond timescale indicates that the initial coordination of an alkyne solvent molecule to the metal center results in a stable intermediate that does not rearrange to form the polymer precursor. This suggests that polymerization requires the dissociation of additional carbonyl ligands before rearrangement can occur. Overall

  6. Fault tolerance analysis of the class of rearrangeable interconnection networks

    SciTech Connect

    Pakzad, S. . Dept. of Electrical Engineering)

    1989-08-01

    This paper analyzes the fault tolerance characteristics of a range or rearrangeable {beta}-networks based on the concepts and the framework developed by S. Pakzad and S. Lakshmivarahan. These rearrangeable {beta}-networks include the Benes network, the Waksman network, the Joel network, and the serial network. In addition, this paper presents a comparative analysis of the aforementioned networks according to their hardware cost, performance, and degree of fault tolerance.

  7. Photoinduced Kondo effect in CeZn3P3

    NASA Astrophysics Data System (ADS)

    Kitagawa, J.; Kitajima, D.; Shimokawa, K.; Takaki, H.

    2016-01-01

    The Kondo effect, which originates from the screening of a localized magnetic moment by a spin-spin interaction, is widely observed in nonartificial magnetic materials, artificial quantum dots, and carbon nanotubes. In devices based on quantum dots or carbon nanotubes that target quantum information applications, the Kondo effect can be tuned by a gate voltage, a magnetic field, or light. However, the manipulation of the Kondo effect in nonartificial materials has not been thoroughly studied; in particular, the artificial creation of the Kondo effect remains unexplored. Per this subject study, however, a route for the optical creation of the Kondo effect in the nonartificial material p -type semiconductor CeZn3P3 is presented. The Kondo effect emerges under visible-light illumination of the material by a continuous-wave laser diode and is ultimately revealed by photoinduced electrical resistivity, which clearly exhibits a logarithmic temperature dependency. By contrast, a La-based compound (LaZn3P3 ) displays only normal metallic behavior under similar illumination. The photoinduced Kondo effect, which occurs at higher temperatures when compared with the Kondo effect in artificial systems, provides a potential range of operation for not only quantum information/computation devices but also for operation of magneto-optic devices, thereby expanding the range of device applications based on the Kondo effect.

  8. Photo-induced reduction of flavin mononucleotide in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Song, S.-H.; Dick, B.; Penzkofer, A.

    2007-01-01

    The photo-induced reduction of flavin mononucleotide (FMN) in aqueous solutions is studied by absorption spectra measurement under aerobic and anaerobic conditions. Samples without exogenous reducing agent and with the exogenous reducing agents ethylene-diamine-tetraacetic acid (EDTA) and dithiothreitol (DTT) are investigated. Under anaerobic conditions the photo-induced reduction with and without reducing agents is irreversible. Under aerobic conditions the photo-reduction without added reducing agent is small compared to the photo-degradation, and the photo-reduction of FMN by the reducing agents is reversible (re-oxidation in the dark). During photo-excitation of FMN the dissolved oxygen is consumed by singlet oxygen formation and subsequent chemical reaction. After light switch-off slow re-oxidation (slow absorption recovery) occurs due to air in-diffusion from surface. EDTA degradation by FMN excitation leads to oxygen scavenging. The quantum efficiencies of photo-reduction under aerobic and anaerobic conditions are determined. The re-oxidation of reduced FMN under aerobic conditions and due to air injection is investigated.

  9. Overview of photo-induced therapy for ATP production

    NASA Astrophysics Data System (ADS)

    Abdalla, Mohamed; Nagy, A.; Ye, W. N.; Mussivand, T.

    2012-10-01

    The purpose of this report is to provide a review of the effects of low-power photo-induced therapy using lasers of different device parameters such as intensity, wavelength, lasing mechanism (i.e., pulsed or continuous) on the production of Adenosine triphosphate (ATP) in mammalian cells. This is a very important research topic as it is suggested in literature that there might be a relationship between the ATP levels and specific diseases. It has been shown that the ATP production was enhanced at wavelengths ranging between 600 nm and 1000 nm (also known as the optical window), in particular at 600nm, 632.8nm, 635nm, 650nm, and 904nm. However, certain experiments showed that the effectiveness of the photo-induced therapy was also dependent on the dosage and the duration of the supplied light. We present the research conclusions drawn from the experiments reported within the last decade, and provide a list of potential medical treatment(s) for patients using visible and near infrared (NIR) light.

  10. Photoinduced effect in Ga Ge S based thin films

    NASA Astrophysics Data System (ADS)

    Messaddeq, S. H.; Li, M. Siu; Inoue, S.; Ribeiro, S. J. L.; Messaddeq, Y.

    2006-10-01

    Glassy films of Ga 10Ge 25S 65 with 4 μm thickness were deposited on quartz substrates by electron beam evaporation. Photoexpansion (PE) (photoinduced increase in volume) and photobleaching (PB) (blue shift of the bandgap) effects have been examined. The exposed areas have been analyzed using perfilometer and an expansion of 1.7 μm (Δ V/ V ≈ 30%) is observed for composition Ga 10Ge 25S 65 exposed during 180 min and 3 mW/cm 2 power density. The optical absorption edge measured for the film Ge 25Ga 10S 65 above and below the bandgap show that the blue shift of the gap by below bandgap photon illumination is considerable higher (Δ Eg = 440 meV) than Δ Eg induced by above bandgap illumination (Δ Eg = 190 meV). The distribution of the refraction index profile showed a negative change of the refraction index in the irradiated samples (Δ n = -0.6). The morphology was examined using a scanning electron microscopy (SEM). The chemical compositions measured using an energy dispersive analyzer (EDX) indicate an increase of the oxygen atoms into the irradiated area. Using a Lloyd's mirror setup for continuous wave holography it was possible to record holographic gratings using the photoinduced effects that occur in them. Diffraction efficiency up to 25% was achieved for the recorded gratings and atomic force microscopy images are presented.

  11. Photoinduced development of antibacterial materials derived from isosorbide moiety.

    PubMed

    Lorenzini, Cedric; Haider, Adnan; Kang, Inn-Kyu; Sangermano, Marco; Abbad-Andalloussi, Samir; Mazeran, Pierre-Emmanuel; Lalevée, Jacques; Renard, Estelle; Langlois, Valérie; Versace, Davy-Louis

    2015-03-01

    A straightforward method for immobilizing in situ generated silver nanoparticles on the surface of a photoactivable isosorbide-derived monomer is developed with the objective to design a functional material having antibacterial properties. The photoinduced thiol-ene mechanism involved in these syntheses is described by the electron spin resonance/spin trapping technique. The resulting materials with or without silver nanoparticles (Ag NPs) were used as films or as coatings on glass substrate. The surface of the synthesized materials was characterized by X-ray photoelectron spectroscopy and scanning electron microscopy, and their thermal and mechanical properties were evaluated by dynamic-mechanical thermal tests, differential scanning calorimetry, thermogravimetric analyses, along with pencil hardness, nanoindentation, and scratch resistance tests. The photoinduced formation of Ag NPs is also confirmed by UV spectrophotometry. Finally, a primary investigation demonstrates the antibacterial properties of the isosorbide-derived material against Staphylococcus aureus and Escherichia coli, as well as its cytocompatibility toward NIH 3T3 fibroblastic cells. PMID:25633575

  12. The dynamics of photoinduced defect creation in amorphous chalcogenides: The origin of the stretched exponential function

    SciTech Connect

    Freitas, R. J.; Shimakawa, K.; Wagner, T.

    2014-01-07

    The article discusses the dynamics of photoinduced defect creations (PDC) in amorphous chalcogenides, which is described by the stretched exponential function (SEF), while the well known photodarkening (PD) and photoinduced volume expansion (PVE) are governed only by the exponential function. It is shown that the exponential distribution of the thermal activation barrier produces the SEF in PDC, suggesting that thermal energy, as well as photon energy, is incorporated in PDC mechanisms. The differences in dynamics among three major photoinduced effects (PD, PVE, and PDC) in amorphous chalcogenides are now well understood.

  13. The dynamics of photoinduced defect creation in amorphous chalcogenides: The origin of the stretched exponential function

    NASA Astrophysics Data System (ADS)

    Freitas, R. J.; Shimakawa, K.; Wagner, T.

    2014-01-01

    The article discusses the dynamics of photoinduced defect creations (PDC) in amorphous chalcogenides, which is described by the stretched exponential function (SEF), while the well known photodarkening (PD) and photoinduced volume expansion (PVE) are governed only by the exponential function. It is shown that the exponential distribution of the thermal activation barrier produces the SEF in PDC, suggesting that thermal energy, as well as photon energy, is incorporated in PDC mechanisms. The differences in dynamics among three major photoinduced effects (PD, PVE, and PDC) in amorphous chalcogenides are now well understood.

  14. Photoinduced currents in pristine and ion irradiated kapton-H polyimide

    SciTech Connect

    Sharma, Anu Sridharbabu, Y. Quamara, J. K.

    2014-10-15

    The photoinduced currents in pristine and ion irradiated kapton-H polyimide have been investigated for different applied electric fields at 200°C. Particularly the effect of illumination intensity on the maximum current obtained as a result of photoinduced polarization has been studied. Samples were irradiated by using PELLETRON facility, IUAC, New Delhi. The photo-carrier charge generation depends directly on intensity of illumination. The samples irradiated at higher fluence show a decrease in the peak current with intensity of illumination. The secondary radiation induced crystallinity (SRIC) is responsible for the increase in maximum photoinduced currents generated with intensity of illumination.

  15. Photoinduced in-plane switching of a photochromic nematic liquid crystal

    SciTech Connect

    Komitov, L.; Yamamoto, J.; Yokoyama, H.

    2001-06-15

    Photoinduced fast in-plane switching of the optic axis of a photochromic nematic liquid crystal is found in a sandwich cell with substrates promoting a twofold degenerate anchoring. The switching process is governed by the modification of the anchoring conditions associated with the photoisomerization of the photochromic nematic liquid crystal. Photoinduced in-plane reorientation of the sample optic axis of about 80{degree} has been found. Together with the model of photoinduced in-plane switching, some implementations of this effect are briefly discussed. {copyright} 2001 American Institute of Physics.

  16. USP6 genetic rearrangements in cellular fibroma of tendon sheath.

    PubMed

    Carter, Jodi M; Wang, Xiaoke; Dong, Jie; Westendorf, Jennifer; Chou, Margaret M; Oliveira, Andre M

    2016-08-01

    Fibroma of tendon sheath is a benign (myo)fibroblastic neoplasm of the tenosynovial soft tissues, typically affecting the distal extremities. It is classically described as a paucicellular, densely collagenized tumor; however, cellular variants have been described. A subset of cellular fibromas of tendon sheath shares similar histological features with nodular fasciitis. As nodular fasciitis very frequently harbors rearrangement of ubiquitin-specific peptidase 6 (USP6), we hypothesized that cellular fibromas of tendon sheath with nodular fasciitis-like features may also contain USP6 rearrangements. Cases of fibroma of tendon sheath (n=19), including cellular (n=9) and classic (n=10) variants, were evaluated for USP6 rearrangement by fluorescence in situ hybridization studies. A subset of cases was tested for MYH9 rearrangements and MYH9-USP6 and CDH11-USP6 fusion products. Classic fibroma of tendon sheath occurred in 5 males and 5 females (median age 67 years, range 23-77 years) as soft tissue masses of the hand (n=4), finger (n=3), forearm (n=1) and foot (n=2). Cellular fibroma of tendon sheath occurred in 5 males and 4 females in a younger age group (median age 32 years, range 12-46 years) as small soft tissue masses of the finger (n=5), hand (n=3) and wrist (n=1). USP6 rearrangements were detected in 6/9 cellular fibromas of tendon sheath. Among cellular fibromas of tendon sheath with USP6 rearrangements, no MYH9 rearrangements were detected. By RT-PCR, neither the MYH9-USP6 or the CDH11-USP6 fusion products were detected in any case. Neither USP6 nor MYH9 rearrangement were detected in any classic fibroma of tendon sheath. We report for the first time the presence of USP6 rearrangements in a subset of cellular fibroma of tendon sheath. Based on the similar morphological and molecular genetic features, we suspect that a subset of cellular fibromas of tendon sheath are under-recognized examples of tenosynovial nodular fasciitis, driven by alternate USP6 fusion

  17. Biotinylated Platinum(II) Ferrocenylterpyridine Complexes for Targeted Photoinduced Cytotoxicity.

    PubMed

    Mitra, Koushambi; Shettar, Abhijith; Kondaiah, Paturu; Chakravarty, Akhil R

    2016-06-01

    Biotinylated platinum(II) ferrocenylterpyridine (Fc-tpy) complexes [Pt(Fc-tpy)(L(1))]Cl (1) and [Pt(Fc-tpy)(L(2))]Cl (2), where HL(1) and HL(2) are biotin-containing ligands, were prepared, and their targeted photoinduced cytotoxic effect in cancer cells over normal cells was studied. A nonbiotinylated complex, [Pt(Fc-tpy)(L(3))]Cl (3), was prepared as a control to study the role of the biotin moiety in cellular uptake properties of the complexes. Three platinum(II) phenylterpyridine (Ph-tpy) complexes, viz., [Pt(Ph-tpy)(L(1))]Cl (4), [Pt(Ph-tpy)(L(2))]Cl (5), and [Pt(Ph-tpy)(L(3))]Cl (6), were synthesized and explored to understand the role of a metal-bound Fc-tpy ligand over Ph-tpy as a photoinitiator. The Fc-tpy complexes displayed an intense absorption band near 640 nm, which was absent in their Ph-tpy analogues. The Fc-tpy complexes (1 mM in 0.1 M TBAP) showed an irreversible cyclic voltammetric anodic response of the Fc/Fc(+) couple near 0.25 V. The Fc-tpy complexes displayed photodegradation in red light of 647 nm involving the formation of a ferrocenium ion (Fc(+)) and reactive oxygen species (ROS). Photoinduced release of the biotinylated ligands was observed from spectral measurements, and this possibly led to the controlled generation of an active platinum(II) species, which binds to the calf-thymus DNA used for this study. The biotinylated photoactive Fc-tpy complexes showed significant photoinduced cytotoxicity, giving a IC50 value of ∼7 μM in visible light of 400-700 nm with selective uptake in BT474 cancer cells over HBL-100 normal cells. Furthermore, ferrocenyl complexes resulted in light-induced ROS-mediated apoptosis, as indicated by DCFDA, annexin V/FITC staining, and sub-G1 DNA content determined by fluorescent activated cell sorting analysis. The phenyl analogues 4 and 5 were photostable, served as DNA intercalators, and demonstrated selective cytotoxicity in the cancer cells, giving IC50 values of ∼4 μM. PMID:27171926

  18. Genome rearrangements caused by interstitial telomeric sequences in yeast

    PubMed Central

    Aksenova, Anna Y.; Greenwell, Patricia W.; Dominska, Margaret; Shishkin, Alexander A.; Kim, Jane C.; Petes, Thomas D.; Mirkin, Sergei M.

    2013-01-01

    Interstitial telomeric sequences (ITSs) are present in many eukaryotic genomes and are linked to genome instabilities and disease in humans. The mechanisms responsible for ITS-mediated genome instability are not understood in molecular detail. Here, we use a model Saccharomyces cerevisiae system to characterize genome instability mediated by yeast telomeric (Ytel) repeats embedded within an intron of a reporter gene inside a yeast chromosome. We observed a very high rate of small insertions and deletions within the repeats. We also found frequent gross chromosome rearrangements, including deletions, duplications, inversions, translocations, and formation of acentric minichromosomes. The inversions are a unique class of chromosome rearrangement involving an interaction between the ITS and the true telomere of the chromosome. Because we previously found that Ytel repeats cause strong replication fork stalling, we suggest that formation of double-stranded DNA breaks within the Ytel sequences might be responsible for these gross chromosome rearrangements. PMID:24191060

  19. DNA Oligonucleotide Fragment Ion Rearrangements Upon Collision-Induced Dissociation

    NASA Astrophysics Data System (ADS)

    Harper, Brett; Neumann, Elizabeth K.; Solouki, Touradj

    2015-08-01

    Collision-induced dissociation (CID) of m/z-isolated w type fragment ions and an intact 5' phosphorylated DNA oligonucleotide generated rearranged product ions. Of the 21 studied w ions of various nucleotide sequences, fragment ion sizes, and charge states, 18 (~86%) generated rearranged product ions upon CID in a Synapt G2-S HDMS (Waters Corporation, Manchester, England, UK) ion mobility-mass spectrometer. Mass spectrometry (MS), ion mobility spectrometry (IMS), and theoretical modeling data suggest that purine bases can attack the free 5' phosphate group in w type ions and 5' phosphorylated DNA to generate sequence permuted [phosphopurine]- fragment ions. We propose and discuss a potential mechanism for generation of rearranged [phosphopurine]- and complementary y-B type product ions.

  20. A versatile reporter system for CRISPR-mediated chromosomal rearrangements.

    PubMed

    Li, Yingxiang; Park, Angela I; Mou, Haiwei; Colpan, Cansu; Bizhanova, Aizhan; Akama-Garren, Elliot; Joshi, Nik; Hendrickson, Eric A; Feldser, David; Yin, Hao; Anderson, Daniel G; Jacks, Tyler; Weng, Zhiping; Xue, Wen

    2015-01-01

    Although chromosomal deletions and inversions are important in cancer, conventional methods for detecting DNA rearrangements require laborious indirect assays. Here we develop fluorescent reporters to rapidly quantify CRISPR/Cas9-mediated deletions and inversions. We find that inversion depends on the non-homologous end-joining enzyme LIG4. We also engineer deletions and inversions for a 50 kb Pten genomic region in mouse liver. We discover diverse yet sequence-specific indels at the rearrangement fusion sites. Moreover, we detect Cas9 cleavage at the fourth nucleotide on the non-complementary strand, leading to staggered instead of blunt DNA breaks. These reporters allow mechanisms of chromosomal rearrangements to be investigated. PMID:26018130

  1. Cell Division Drives Epithelial Cell Rearrangements during Gastrulation in Chick.

    PubMed

    Firmino, Joao; Rocancourt, Didier; Saadaoui, Mehdi; Moreau, Chloe; Gros, Jerome

    2016-02-01

    During early embryonic development, cells are organized as cohesive epithelial sheets that are continuously growing and remodeled without losing their integrity, giving rise to a wide array of tissue shapes. Here, using live imaging in chick embryo, we investigate how epithelial cells rearrange during gastrulation. We find that cell division is a major rearrangement driver that powers dramatic epithelial cell intercalation events. We show that these cell division-mediated intercalations, which represent the majority of epithelial rearrangements within the early embryo, are absolutely necessary for the spatial patterning of gastrulation movements. Furthermore, we demonstrate that these intercalation events result from overall low cortical actomyosin accumulation within the epithelial cells of the embryo, which enables dividing cells to remodel junctions in their vicinity. These findings uncover a role for cell division as coordinator of epithelial growth and remodeling that might underlie various developmental, homeostatic, or pathological processes in amniotes. PMID:26859350

  2. Low-Temperature Cationic Rearrangement in a Bulk Metal Oxide.

    PubMed

    Li, Man-Rong; Retuerto, Maria; Stephens, Peter W; Croft, Mark; Sheptyakov, Denis; Pomjakushin, Vladimir; Deng, Zheng; Akamatsu, Hirofumi; Gopalan, Venkatraman; Sánchez-Benítez, Javier; Saouma, Felix O; Jang, Joon I; Walker, David; Greenblatt, Martha

    2016-08-16

    Cationic rearrangement is a compelling strategy for producing desirable physical properties by atomic-scale manipulation. However, activating ionic diffusion typically requires high temperature, and in some cases also high pressure in bulk oxide materials. Herein, we present the cationic rearrangement in bulk Mn2 FeMoO6 at unparalleled low temperatures of 150-300 (o) C. The irreversible ionic motion at ambient pressure, as evidenced by real-time powder synchrotron X-ray and neutron diffraction, and second harmonic generation, leads to a transition from a Ni3 TeO6 -type to an ordered-ilmenite structure, and dramatic changes of the electrical and magnetic properties. This work demonstrates a remarkable cationic rearrangement, with corresponding large changes in the physical properties in a bulk oxide at unprecedented low temperatures. PMID:27203790

  3. Rearrangement Reactions Catalyzed by Cytochrome P450s

    PubMed Central

    Ortiz de Montellano, Paul R.; Nelson, Sidney D.

    2010-01-01

    Cytochrome P450s promote a variety of rearrangement reactions both as a consequence of the nature of the radical and other intermediates generated during catalysis, and of the neighboring structures in the substrate that can interact either with the initial radical intermediates or with further downstream products of the reactions. This article will review several kinds of previously published cytochrome P450-catalyzed rearrangement reactions, including changes in stereochemistry, radical clock reactions, allylic rearrangements, “NIH” and related shifts, ring contractions and expansions, and cyclizations that result from neighboring group interactions. Although most of these reactions can be carried out by many members of the cytochrome P450 superfamily, some have only been observed with select P450s, including some reactions that are catalyzed by specific endoperoxidases and cytochrome P450s found in plants. PMID:20971058

  4. Modeling and experimental study of photoinduced anisotropy in hybrid solgel films

    NASA Astrophysics Data System (ADS)

    Raschellà, Raffaella; Marino, Iari-Gabriel; Razzetti, Carlo; Bersani, Danilo; Lottici, Pier P.

    2007-03-01

    The mechanism of photoinduced anisotropy through photoisomerization has been studied by measuring photoinduced dichroism and birefringence in solgel silica-based glasses containing an azo dye (Disperse Red 1) and a plasticizer (carbazole). The equations commonly adopted to describe the molecular orientation (Sekkat's theory) have been solved numerically and analytically within two different approximations. The results have been applied to photoinduced birefringence measured with expanded beams, and the dominant mechanisms driving the azo-dye molecular orientation in the investigated materials during both illumination and relaxation have been inferred. The experiments of photoinduced dichroism, performed with nonexpanded beams, suggest that the distribution of times describing the kinetics of the anisotropy formation, usually attributed to inhomogeneities in the chromophore environment, may be ascribed instead to the nonuniform profile of the beams.

  5. A Photoinduced Cobalt-Catalyzed Synthesis of Pyrroles through in Situ-Generated Acylazirines.

    PubMed

    Pusch, Stefan; Kowalczyk, Danuta; Opatz, Till

    2016-05-20

    Tetrasubstituted pyrroles can be synthesized in a one-pot procedure from isoxazoles. The process includes the photoinduced in situ formation of acylazirines combined with a subsequent cobalt(II)-catalyzed ring expansion with 1,3-diketones. PMID:27081704

  6. Photoinduced underwater superoleophobicity of TiO2 thin films.

    PubMed

    Sawai, Yusuke; Nishimoto, Shunsuke; Kameshima, Yoshikazu; Fujii, Eiji; Miyake, Michihiro

    2013-06-11

    The photoinduced wettabilities of water, n-hexadecane, dodecane, and n-heptane on a flat TiO2 surface prepared by a sol-gel method-based coating were investigated. An amphiphilic surface produced by UV irradiation exhibited underwater superoleophobicity with an extremely high static oil contact angle (CA) of over 160°. The TiO2 surface almost completely repelled the oil droplet in water. A robust TiO2 surface with no fragile nanomicrostructure was fabricated on a Ti mesh with a pore size of approximately 150 μm. The fabricated mesh was found to be applicable as an oil/water separation filter. PMID:23701360

  7. NA-ESMD modeling of photoinduced dynamics in conjugated molecules

    NASA Astrophysics Data System (ADS)

    Nelson, Tammie; Fernandez-Alberti, Sebastian; Chernyak, Vladimir; Roitberg, Adrian; Tretiak, Sergei

    2011-03-01

    The evolution of electronic excitations in optically active molecules can generally be defined by non-adiabatic (NA) dynamics. A number of fundamental and complex processes are associated with NA dynamics. To treat ultrafast excited state dynamics we have developed a non-adiabatic excited state molecular dynamics (NA-ESMD) framework incorporating quantum transitions. Our calculations combine the Collective Electronic Oscillator (CEO) package with the Tully's fewest switches algorithm for surface hopping, and the actual potential energy surfaces of the excited states are used. This method is applied to model the photoinduced dynamics of distyrylbenzene. Our analysis shows intricate details of vibronic relaxation and identifies specific slow and fast nuclear motions that are strongly coupled to the electronic degrees of freedom. Non-adiabatic relaxation of the highly excited mAg state is predicted to occur on a femtosecond timescale at room temperature and on a picosecond timescale at low temperature.

  8. DNA Intercalated Psoralen Undergoes Efficient Photoinduced Electron Transfer.

    PubMed

    Fröbel, Sascha; Reiffers, Anna; Torres Ziegenbein, Christian; Gilch, Peter

    2015-04-01

    The interaction of psoralens with DNA has been used for therapeutic and research purposes for decades. Still the photoinduced behavior of psoralens in DNA has never been observed directly. Femtosecond transient absorption spectroscopy is used here to gain direct insight into the photophysics of a DNA-intercalated psoralen (4'-aminomethyl-4,5',8-trimethyl-psoralen (AMT)). Intercalation reduces the excited singlet lifetime of AMT to 4 ps compared with 1400 ps for AMT in water. This singlet quenching prohibits the population of the triplet state that is accessed in free AMT. Instead, a DNA to AMT electron transfer takes place. The resulting radical pair decays primarily via charge recombination with a time constant of 30 ps. The efficient electron transfer observed here reveals a completely new aspect of the psoralen-DNA interaction. PMID:26262984

  9. Photo-induced trimming of chalcogenide-assisted silicon waveguides.

    PubMed

    Canciamilla, Antonio; Morichetti, Francesco; Grillanda, Stefano; Velha, Philippe; Sorel, Marc; Singh, Vivek; Agarwal, Anu; Kimerling, Lionel C; Melloni, Andrea

    2012-07-01

    A chalcogenide-assisted silicon waveguide is realized by depositing a thin layer of A(2)S(3) glass onto a conventional silicon on insulator optical waveguide. The photosensitivity of the chalcogenide is exploited to locally change the optical properties of the waveguide through exposure to visible light radiation. Waveguide trimming is experimentally demonstrated by permanently shifting the resonant wavelength of a microring resonator by 6.7 nm, corresponding to an effective index increase of 1.6·10(-2). Saturation effects, trimming range, velocity and temporal stability of the process are discussed in details. Results demonstrate that photo-induced treatments can be exploited for a post-fabrication compensation of fabrication tolerances, as well as to set and reconfigure the circuit response. PMID:22772270

  10. Photo-induced reflectivity in the mid and far infrared

    SciTech Connect

    Haar, P.; Harrington, K.J.; Schwettman, H.A.

    1995-12-31

    Interest in switching FEL beams has motivated studies of photo-induced reflectivity in the mid and far infrared. We are particularly interested in Ge{sup 4}, GaAs, and Si{sup 5}, materials that can be pumped with a visible or near-IR conventional laser and which together cover the wavelengths from 3-100{mu}m. We have made quantitative measurements to determine the induced reflectivity, carrier lifetime, and transient absorption of these materials at several wavelengths across this range using a variety of pump laser wavelengths and pulse lengths. These measurements allow us to determine the feasibility of single pulse selection and cavity dumping with our FELs at high repetition rates.