Electronic spectra of dithieno analogues of phenanthrene

The magnetic circular dichroism (MCD) spectra of some dithieno analogues of phenanthrene: benzo [2,1-b;3,4-b′] dithiophene (I) benzo [1,2-b;4,3-b′] dithiophene (II), benzo [1,2-c;3,4-c′] dithiophene (III) and benzo [1,2-b;3,4-b′] dithiophene (IV) are reported. For I–III the spectra corresponding to two different transition moment directions could be obtained from low-temperature linear dichroism spectra. The results compare well with theoretical energies, oscillator strengths, moment directions and MCD B-terms which were obtained from semi-empirical quantum mechanical calculations in the π-electron approximation.     

Mass spectral fragmentation patterns of heterocycles. IV . Tetracyclic phenothiazines. IX. Electron impact promoted mass spectral fragmentation of pyrrolo[3,2,1-kl]phenothiazine

The mass spectral fragmentation patterns of pyrrolo[3, 2, 1-kl]phenothiazine ( 1 ) and its 1, 10-dideuterioderi-vative [2] are reported. The site of deuterium substitution in 2 was established by examination of its ¹³C nuclear magnetic resonance spectrum. The heteroaromatic stability of 1 to electron impact is exemplified by the occurrence of the molecular ion as the base peak and the formation of a reasonably intense M²⁺ ion. An intense M-1 ion is also observed. The more abundant fragment ions appear to result from sulfur ionization. Fragment ions arising from ionization of the nitrogen constitute only a small fraction of the total ion current. Proposed fragmentation pathways of 1 are supported by the detection of appropriate metastable ions, exact mass measurements, and electron impact spectrum of 2 .     

An experimental study of the 9Be(p, π+)10Be and 9Be(p, π−)10C reactions at 185 MeV

A magnetic spectrometer was used for the momentum analysis of pions produced by 185 MeV protons on a ⁹Be target. The obtained energy resolution (0.55 MeV FWHM) made it possible to resolve a number of discrete final states in ¹⁰Be and ¹⁰C. Energy spectra were measured in the angular region 15°–130° (lab). Angular distributions for six peaks in ¹⁰Be and four peaks in ¹⁰C are presented in tables and graphs. A peak corresponding to a not previously reported level in ¹⁰Be was observed at 11.75 ±0.11 MeV excitation energy. The measured $\text{π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}$ ratio for the ground state analogues was found to be angular dependent and varied from 30 at 35° (lab) to 2 at 125° (lab). The results are compared with theoretical predictions and discussed in terms of one- and two-nucleon models.     

Experimental and theoretical studies of positive pion production on 10B and 40Ca by 163–186 MeV protons

The reactions ${}^{10}\text{B(p}\text{,π}{}^{\mathrm{+}}\text{)}{}^{11}\text{B}$ and ${}^{40}\text{Ca(p}\text{,π}{}^{\mathrm{+}}\text{)}{}^{41}\text{Ca}$ have been studied for proton energies between 163 and 186 MeV. Angular distributions for the ground states and the excited state at 2.13 MeV in ¹¹B are presented. Cross sections calculated in the one-nucleon model, under different assumptions about the interaction Hamiltonian as well as the pion and proton optical potentials, are compared with the experimental distribution from the $\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ state in ⁴¹Ca.     

Perfusion and chemical monitoring of living cells on a microfluidic chip

A microfluidic device that incorporates continuous perfusion and an on-line electrophoresis immunoassay was developed, characterized, and applied to monitoring insulin secretion from single islets of Langerhans. In the device, a cell chamber was perfused with cell culture media or a balanced salt solution at 0.6 to 1.5 microL min(-1). The flow was driven by gas pressure applied off-chip. Perfusate was continuously sampled at 2 nL min(-1) by electroosmosis through a separate channel on the chip. The perfusate was mixed on-line with fluorescein isothiocyanate-labeled insulin (FITC-insulin) and monoclonal anti-insulin antibody and allowed to react for 60 s as the mixture traveled down a 4 cm long reaction channel. The cell chamber and reaction channel were maintained at 37 degrees C. The reaction mixture was injected onto a 1.5 cm separation channel as rapidly as every 6 s, and the free FITC-insulin and the FITC-insulin-antibody complex were separated under an electric field of 500 to 600 V cm(-1). The immunoassay had a detection limit of 0.8 nM and a relative standard deviation of 6% during 2 h of continuous operation with standard solutions. Individual islets were monitored for up to 1 h while perfusing with different concentrations of glucose. The immunoassay allowed quantitative monitoring of classical biphasic and oscillatory insulin secretion with 6 s sampling frequency following step changes in glucose from 3 to 11 mM. The 2.5 cm x 7.6 cm microfluidic system allowed for monitoring islets in a highly automated fashion. The technique should be amenable to studies involving other tissues or cells that release chemicals.     

Extending the Ree-Eyring generalized flow theory to non-equilibrium conditions

Summary It is stated that theRee-Eyring treatment of the entanglement-disentanglement transition does not satisfactorily describe the non-equilibrium states. By introducing theKubát theory of relaxation theRee-Eyring flow theory can be extended to those states, in agreement with experimental observations.

---

Zusammenfassung Es wird gezeigt, da? dieRee-Eyringsche Behandlung der Verflechtungs-Entfleohtungs-Umlagerung die Nicht-Gleichgewichtszust?nde nicht befriedigend beschreibt. Durch Einführung derKubátschen Theorie der Relaxation wird dieRee-Eyringsche Flie?theorie in übereinstimmung mit experimentellen Beobachtungen an solchen Zust?nden erweitert.

     

COMPARISON BETWEEN THE LUMINOL-DEPENDENT CHEMILUMINESCENCE OF POLYMORPHONUCLEAR LEUKOCYTES AND OF THE MYELOPEROXIDASE-HOOH SYSTEM: INFLUENCE OF pH, CATIONS AND PROTEIN

Abstract— Measurements of luminol-dependent chemiluminescence (CL) from normal human polymorphonuclear leukocytes (PMNL) were carried out and the results were compared to the CL obtained from a cell-free myeloperoxidase(MPO)-HOOH-system.
The chemotactic peptide formylmethionyl-leucyl-phenyl-alanine (fMLP) induced a bimodal luminol-dependent CL response in PMNL, while phorbol myristate acetate (PMA) induced a one-peak response. Calcium was found to be required for the fMLP but not for the PMA induced response. The absence of glucose reduced the PMA but not the fMLP induced PMNL CL response. Neither calcium nor glucose had any effect on the light emitted from a cell-free MPO-HOOH-system.
The PMNL CL response to both fMLP and PMA was affected by the pH-value, in that at a low pH (6.3) the response was decreased and at a high pH (8.0) the response was increased. These effects were also obtained in cell-free MPO-HOOH-systems. The presence of human serum albumin (HSA) totally inhibited the CL of a cell-free MPO-HOOH-system while, in PMNL CL, HSA reduced only the first phase of the fMLP induced response.
The results are discussed in view of the fact that CL is increasingly used as a clinical instrument to study defects in PMNL function and the effects on PMNL function of various agents such as drugs.