There are two principal mechanisms of acetylcholine (ACh) release from the resting motor nerve terminal: quantal and non-quantal (NQR); the former being only a small fraction of the total, at least at rest. In the present article we summarize basic research about the NQR that is undoubtedly an important trophic factor during endplate development and in adult neuromuscular contacts. NQR helps to...

A reinvestigation of the nitrogen-14 NQR in thiourea has permitted to record, apparently for the first time, the resonances above 169 K. The first order and second order of the transitions at 169 K and 202 K, respectively, appear clearly from the temperature dependence of the resonance frequencies; the modulated structure, incommensurate or commensurate, is also seen on the N NQR spectrum. This...

Z. Naturforsch. 51a, 793 -796 (1996); received February 1, 1996 We have carried out Ru N M R and NQR measurements in superconductor CeRu 2 having Tc = 6.1 K in the temperature range of 1 . 3 3 0 K. From the 9 y Ru N M R in 10.2 T above H c 2 , T { T c o n s t was found in the measured-T range, and the value of T , T K 2 is almost the same as that in the uncorrelated Korringa relation, suggestin...

An electron spm echo modulation frequency analysis of P*-860 is performed in 14N chromatophores of RhodospiMhn ncbrum, and in “‘N substituted reaction centers from Rhodopseudomonas spheeroides 2.4.1, For the 14N matcnal two sets of nuclear quadrupole parameters are obtained. From the frequencies found for 15N reaction centers the perpendicular, paraIM and isotropic hypcrfime coupling constants ...

The performance of rectangular radio frequency (RF) coils capable of being used to detect nuclear quadrupole resonance (NQR) signals from blister packs of medicines has been compared. The performance of a fixed-pitch RF coil was compared with that from two variable-pitch coils, one based on a design in the literature and the other optimized to obtain the most homogeneous RF field over the whole...

A pulsed NQR spectrometer specifically designed to facilitate real-time tuning of pulse sequence parameters is described. A modular approach based on the interconnection of several rack-mounted blocks provides easy access to all spectrometer signals and simplifies the task of modifying the spectrometer design. We also present experimental data that demonstrates the ability of the spectrometer t...

A mechanism for creating amino acid enantiomerism that always selects the same large-scale chirality is identified, and subsequent chemical replication and galactic mixing that would populate the Galaxy with the predominant species is described. This involves (1) the spin of the 14N in the amino acids, or in precursor molecules from which amino acids might be formed, that couples to the chirali...

The 1 2 7 I-NQR of(HOCH 2 )3 CNH 3 I was determined in the range 77 < T/K<310. At T = 310 K the NQR signal fades out (Tm = 463 K). The 127I spectrum ( T =77 K.): v, =29.195 MHz, v2 = 14.597 MHz, rj(121l)=0, e Q # zz6 _ 1 (1 2 7 I) = 97.315 MHz, is in agreement with the crystal structure. The 127I NQR spectrum of l,3-diammonium-2,2-dimethylpropane diiodide, (H 3 NCH 2 C(CH 3 ) 2 CH 2 N H 3)2+ -2...

A very high sensitivity continuous wave NQR spectrometer was developed to detect pure NQR transitions at low frequencies (down to 200 kHz). A signal-to-noise ratio of more than 100 to 1 has been achieved at about 1.36 MHz for crystalline B 2 0 3 . Two large n B responses have been found in vitreous B 2 0 3 (NMR detected only one site) with linewidths of less than 30 kHz. A1 NQR spectra were obt...

It is demonstrated that deep circulation mixing below the base of the standard convective envelope, and the consequent “cool bottom processing” (CBP) of the CNO isotopes, can reproduce the trend with stellar mass of the 12C/13C observations in low mass red giants. (This trend is opposite to what is expected from standard first dredge-up.) Our models assume that extra mixing always reaches to th...