The intriguing recovery of an extremely Cu-rich cupropearceite crystal (Cu = 7.62 a.p.f.u.) from Tsumeb, Namibia, allowed us to study the effect of the entry of Cu in the positions usually occupied by Ag in the B module layer in the structure of the minerals belonging to the pearceite-polybasite group. Electron microprobe analysis yields the formula [Cu6(As1.89Fe0.01) Σ=1.90S7.05][(Ag8.36Cu0.62...

Somatic embryogenesis was initiated in C. sativus L. from shoot meristems on LS medium containing BAP (2×10-5 M)+NAA (2×10-5 M). Various stages of somatic embryogenesis were observed in the same medium and the development was asynchronous. Somatic embryo development proceeded through well recognized sequences (globular to embryoids) with clearly discernible bipolar regions. Matured embryos coul...

somatic embryogenesis was initiated in c. sativus l. from shoot meristems on ls medium containing bap (2×10-5 m)+naa (2×10-5 m). various stages of somatic embryogenesis were observed in the same medium and the development was asynchronous. somatic embryo development proceeded through well recognized sequences (globular to embryoids) with clearly discernible bipolar regions. matured embryos coul...

In vitro culture systems using bone marrow cells from BALB/C mice were set up in medium supplemented with spleen-derived medium. Bone marrow cells grown in spleen-derived medium gave rise to cultures containing >97% mast cells. The cells were used in polarisation chemotaxis assays with the intention of determining the effect of nerve tissue-derived neurotransmitters on mast cell migration. ...

Freshly enucleated rabbit eyes were refrigerated at +4 degrees C under standard eye bank conditions for 2, 6, 9, and 21 days. One group of corneas with a scleral rim were excised and placed in M-K medium, stored for 18, 24, or 48 hr at +4 degrees C; they were then removed, and endothelial cell viability was evaluated with nitroblue tetrazolium. The cells were examined by light microscopy and sc...

The electrochemical oxidation behavior of m-nitrophenol (m-NP) was studied comparatively on glassy carbon electrode, Pt electrode, PbO2 electrode, SnO2 electrode, and graphite electrode using cyclic voltammetry. The cyclic voltammetry measurements were performed in acidic (1 M H2SO4, pH 0.4), neutral (1 M Na2SO4, pH 6.8), and...

We consider a continuum model of dendritic spines with active membrane dynamics uniformly distributed along a passive dendritic cable. By considering a systematic reduction of the HodgkinHuxley dynamics that is valid on all but very short time-scales we derive 2 dimensional and 1 dimensional systems for excitable tissue, both of which may be used to model the active processes in spine-heads. In...