A Sex-Specific Metabolite Identified in a Marine Invertebrate Utilizing Phosphorus-31 Nuclear Magnetic Resonance

Hormone level differences are generally accepted as the primary cause for sexual dimorphism in animal and human development. Levels of low molecular weight metabolites also differ between men and women in circulating amino acids, lipids and carbohydrates and within brain tissue. While investigating the metabolism of blue crab tissues using Phosphorus-31 Nuclear Magnetic Resonance, we discovered that only the male blue crab (Callinectes sapidus) contained a phosphorus compound with a chemical shift well separated from the expected phosphate compounds. Spectra obtained from male gills were readily differentiated from female gill spectra. Analysis from six years of data from male and female crabs documented that the sex-specificity of this metabolite was normal for this species. Microscopic analysis of male and female gills found no differences in their gill anatomy or the presence of parasites or bacteria that might produce this phosphorus compound. Analysis of a rare gynandromorph blue crab (laterally, half male and half female) proved that this sex-specificity was an intrinsic biochemical process and was not caused by any variations in the diet or habitat of male versus female crabs. The existence of a sex-specific metabolite is a previously unrecognized, but potentially significant biochemical phenomenon. An entire enzyme system has been synthesized and activated only in one sex. Unless blue crabs are a unique species, sex-specific metabolites are likely to be present in other animals. Would the presence or absence of a sex-specific metabolite affect an animal's development, anatomy and biochemistry

Vacuum microdevices

In the paper MEMS-type microsystems working in vacuum conditions are described. All the benefits and drawbacks of vacuum generated in microcavities are discussed. Different methods are used to produce vacuum in microcavity of MEMS. Some bonding techniques, sacrificial layer method or getter materials are presented. It is concluded that the best solution would be to invent some kind of vacuum micropump integrated with MEMS structure. Few types of already existing vacuum micropumps are shown, but they are not able to generate high vacuum. As the most promising candidate for miniaturization an orbitron pump was selected. The working principle and novel concepts of its construction are described. The most important part of the micropump, used for gas ionization, is a field-emission electron source. Results of a research on a lateral electron source with gold emissive layer for integration with a micropump are presented