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The X chromosome of Drosophila provides a unique system for the study of modulation of eukaryotic gene activity.

Syntheses of 1-tert-butyl-(1a), 1-trimethylsilyl-(1b) and 1-trimethylgermanyl-4,4-dimethylcyclohexene (1c) are described as are those of 6-tert-butyl- (2a), 6-trimethylsilyl- (2b) and 6-trimethylgermanyl-3,3-dimethylcyclohexene (2c). The stereochemistry of the hydroboration of these alkenes is examined. The stereochemistry is governed, on the one hand, by the steric influence of the various substituents and on the other by the steric and electronic effects of the trimethylsilyl and trimethylgermanyl groups. [Journal translation]

Si stabiliscono alcune relazioni numeriche fra i caratteri di un sistema algebrico di ∞1curve, appartenente ad una superficie algebrica. Si stabilisce inoltre, una relazione funzionale che intercede fra certe curve strettamente collegate al sistema algebrico, e una curva canonica della superficie.

Isolated spermatozoa incubated in the presence of serum or plasma are chemotactic in vitrofor guinea-pig peritoneal macrophages. On the other hand, seminal fluid with or without spermatozoa, when incubated with serum or plasma, attracts only neutrophils, even from exudates where macrophages are the predominant cell-type.

The vertical intensities of μ+- and μ−-mesons have been measured by means of a counter apparatus with magnetic discrimination for the sign of charge. The mean daily counting rates are 5 500 μ+and 4 600 μ−extended over 18 months. The coefficients for correlation between the intensities of the μ+and μ−with the atmospheric pressure at sea-level (α+and α−) and with the height of the 100 mb layer (γ+and γ−) have been obtained. There is a difference between the coefficients for the two types of mesons which is beyond the statistical errors; in fact |α−| > |α+| and |γ+| > |γ−|. The results have been interpreted by means of a particular integral of the diffusion equation, considering the mesons as being produced by two distinct sources: one due to the collisions between the primary component with the nuclei of the upper atmosphere and the other due to the secondary nucleonic component.

The chemotactic activity for neutrophil leucocytes of the isolated spermatozoa and of the sperm-free seminal fluid was studied by a modification of Boyden's technique. Both spermatozoa and seminal fluid were found to attract neutrophils in the presence of serum or plasma, but not in their absence. The activity of seminal fluid is probably mediated in part by the complement system but it is unlikely that the classical haemolytic complement reaction is responsible for the activity of spermatozoa.

Raman spectra are reported for gaseous BiBr3and PbCl2at temperatures just above their boiling points. The strong resonance fluorescence due to subhalide species that is normally observed in these vapors (with 4880 Å excitation) was suppressed by addition of equimolar amounts of the corresponding mercuric halide. The observed Raman bands for the BiBr3-HgBr2sample, which are attributable to BiBr3, confirm a pyramidal structure having C3Vpoint symmetry. The spectrum attributable to PbCl2in the case of the PbCl2-HgCl2sample is consistent with a symmetric bent structure.