Observation of the ABC effect and final-state isospin

Despite the number of inclusive measurements of the pionic fusion reactions, the nature of the ABC effect discovered in 1960 was not completely established. Exclusive measurements of the doublepion-production reactions leading to either fused d, ³He and ⁴He nuclear final states or pp pairs are analyzed. A significant ABC effect—enhancement in the region of low ππ mass—is found only in the isoscalar ππ channel while in the isovector channels it is small or absent. For the reaction with isovector pp final state an ABC effect was not observed even at the special kinematic conditions to reproduce a quasi-bound two-proton state. The total cross sections for the d and 4He fusion reactions show similar resonance-like energy dependence.     

A one pot synthesis of annulated carbazole analogs

A ZnBr₂-mediated arylation of N-protected 2/3-bromomethylindoles containing an electron-deficient malonylidene unit with arenes at 80 °C led to the formation of arylated products, which on unprecedented 1,5-sigmatropic rearrangement followed by electrocyclization and subsequent aromatization with loss of diethylmalonate furnished the corresponding annulated carbazoles in reasonable yields.     

Eigensolutions,virial theorem and molecular study of nonrelativistic Krazer-Fues potential

A Kratzer-Fues potential is coupled with its self to form a double Kratzer-Fues potential. The solutions of the radial Schrödinger equation with the combined potential are obtained via two different methodologies. Using the supersymmetric approach, the energy equation for a non-approximated centrifugal term is obtained. The energy equation for the approximated centrifugal term is obtained using the parametric Nikiforov-Uvarov method. Numerical results are computed for five molecules using MATLAB software program. The computed numerical values are compared with the experimental values and the ground state energy obtained from Herzberg's energy level equation. The study revealed that the results of the approximated centrifugal term are better than the results of the non-approximated centrifugal term for four molecules.     

Amino‐Functionalized Cellulose Nanoparticles: Preparation,Characterization, and Interactions with Living Cells

Spherical nanoparticles with sizes from 80 to 200 nm are obtained by self‐assembly of highly functionalized 6‐deoxy‐6‐(ω‐aminoalkyl)aminocellulosecarbamates. The particles are very stable, nontoxic, and possess primary amino groups that are accessible to further modifications in aqueous suspension. The particles can be labeled with rhodamine B isothiocyanate without changing their size, stability, and shape. The nanoparticles obtained are investigated by means of photo correlation spectroscopy, zeta potential measurements, SEM and fluorescence spectroscopy. Incorporation of the nanoparticles in human foreskin fibroblasts BJ‐1‐htert and breast carcinoma MCF‐7 cells without any transfection reagent is proved by means of confocal laser scanning microscopy.

     

Explicit time-reversal violating interactions for nuclear physics

Starting from a T-violating Lagrangian involving the nucleon, meson and electro magnetic fields interacting at a point, we calculate the one meson exchange diagram and obtain the longest range part of a two-nucleon electromagnetic operator. The cases when the meson is scalar, pseudoscalar and vector are considered. For the radiation of a real photon the multipole expansions of the transition operators are obtained. The properties and expected magnitudes of the resulting explicit two-nucleon transition operators are examined and compared to the normal operators. With the interactions at ‘maximal’ strength any contributions from the vector operators are negligible and violations from the other operators are only likely to reach the order of 10^?3 where the normal transitions are strongly inhibited.When the photon is virtual the interactions lead to explicit T-violating three-nucleon potentials. These potentials give practically no contributions to optical model potentials. The best reciprocity experiments appear to be nucleon transfer reactions, and there could be violations of the order of 10^?3 in (d ? p) reactions from the pseudoscalar potential. This potential is shown to give a stripping amplitude with angular properties very different from the normal one.     

Field characterization of therapeutic ultrasound phased arrays through forward and backward planar projection

Spatial planar projection techniques propagate field measurements from a single plane in front of a transmitter to arbitrary new planes closer to or further away from the source. A linear wave vector frequency-domain projection algorithm is applied to the acoustic fields measured from several focused transducer arrays designed for ultrasound therapy. A polyvinylidene difluoride hydrophone is first scanned in a water tank over a plane using a three-dimensional positioning system to measure the complex pressure field as a function of position. The field is then projected to a series of new planes using the algorithm. Results of the projected fields are compared with direct measurements taken at corresponding distances. Excellent correlation is found between the projected and measured data. The method is shown to be accurate for use with phase-controlled field patterns, providing a rapid and accurate method for obtaining field information over a large spatial volume. This method can significantly simplify the characterization procedure required for phased-array application used for therapy. Most significantly, the wavefront propagated back to a phased array can be used to predict the field produced by different phase and amplitude settings of the array elements. A field back-projected to the source could be used as an improved source function in acoustic modeling.     

On the production of \pi^{+}_{} \pi^{+}_{} pairs in pp collisions at 0.8 GeV

Data accumulated recently for the exclusive measurement of the pp $ \rightarrow$ pp $ \pi^{+}_{}$ $ \pi^{-}_{}$ reaction at a beam energy of 0.793GeV using the COSY-TOF spectrometer have been analyzed with respect to possible events from the pp $ \rightarrow$ nn $ \pi^{+}_{}$ $ \pi^{+}_{}$ reaction channel. The latter is expected to be the only $ \pi$ $ \pi$ production channel, which contains no major contributions from resonance excitation close to threshold and hence should be a good testing ground for chiral dynamics in the $ \pi$ $ \pi$ production process. No single event has been found, which meets all conditions for being a candidate for the pp $ \rightarrow$ nn $ \pi^{+}_{}$ $ \pi^{+}_{}$ reaction. This gives an upper limit for the cross-section of 0.16μb (90% C.L.), which is more than an order of magnitude smaller than the cross-sections of the other two-pion production channels at the same incident energy.     

Poor Voice Quality in Future Elite Vocal Performers and Professional Voice Users

The voice quality of 86 occupational voice users, i.e., students of a high school for audiovisual communication, was assessed by means of a multidimensional test battery containing: the GRBAS scale, videolaryngostroboscopy, maximum phonation time, jitter, lowest intensity, highest frequency, dysphonia severity index (DSI), and voice handicap index (VHI). In a questionnaire on daily habits the prevalence of smoking, eating habits, and vocal abuse were recorded. A comparison of the voice characteristics of the future occupational voice users with a control group revealed significant differences. The results of the VHI and the DSI of these students revealed significantly worse scores than the score of a control group characterized by no vocal complaints. Moreover, the questionnaire on daily habits showed that the future elite vocal performers and professional voice users take less precautions for the care of their voices. These findings support the importance of a good balanced vocal coaching.     

Isomerisation et polymerisation du cis-pentadiene-1,3

Cis-1,3-pentadiene can be polymerized in benzene solution by a catalyst formed from triethylaluminium and n-butylorthotitanate. When the molar ration Al/Ti is below 6, polymerization proceeds through a previous cis-trans isomerization of the diene. It has been possible to measure the two rate constants (k_t and k_p) which characterize the isomerization and the polymerization steps, respectively. The first one reaches its highest value when Al/Ti equals 2·6 and k_p is maximum when Al/Ti equals 6. Chloroform, which is a very efficient inhibitor for the polymerization, does not affect isomerization. Data are given on the microstructures of the polydienes so obtained.     

Methylating peptides to prevent adduct ion formation also directs cleavage in collision-induced dissociation mass spectrometry

We investigated the effect of N-terminal amino group and carboxyl group methylation on peptide analysis by electrospray mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Permethylation of the N-terminal amino group and the carboxyl groups can reduce metal ion adducts but does not enhance sensitivity in electrospray as previously observed for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. N-terminal trimethylated peptides exhibit collision-induced dissociation (CID) tandem mass spectra that differ from their unmodified analogs; the results support the mobile proton hypothesis of peptide fragmentation. A permanent positive charge at the N-terminus leads to competition between permanent-charge directed processes and loss of the N-terminal trimethyl amino group. Carboxyl methylation has no effect on fragmentation behavior other than to shift the mass of fragments containing methylated carboxyl groups. Comparison of regular and tandem mass spectra of different methylated peptides allowed probing the location of incomplete methylation, the proton displaced by alkali metal ions and the purity of a mass-selected methylated peptide ion.