Deep high-temperature hydrothermal circulation in a detachment faulting system on the ultra-slow spreading ridge.

Coupled magmatic and tectonic activity plays an important role in high-temperature hydrothermal circulation at mid-ocean ridges. The circulation patterns for such systems have been elucidated by microearthquakes and geochemical data over a broad spectrum of spreading rates, but such data have not been generally available for ultra-slow spreading ridges. Here we report new geophysical and fluid geochemical data for high-temperature active hydrothermal venting at Dragon Horn area (49.7°E) on the Southwest Indian Ridge. Twin detachment faults penetrating to the depth of 13 ± 2 km below the seafloor were identified based on the microearthquakes. The geochemical composition of the hydrothermal fluids suggests a long reaction path involving both mafic and ultramafic lithologies. Combined with numerical simulations, our results demonstrate that these hydrothermal fluids could circulate ~ 6 km deeper than the Moho boundary and to much greater depths than those at Trans-Atlantic Geotraverse and Logachev-1 hydrothermal fields on the Mid-Atlantic Ridge.

Neural logic molecular, counter-intuitive.

A hypothesis is proposed that multiple "LOGIC" genes control Boolean logic in a neuron. Each hypothetical LOGIC gene encodes a transcription factor that regulates another LOGIC gene(s). Through transcription regulation, LOGIC genes connect into a complex circuit, such as a XOR logic gate or a two-input flip-flop logic circuit capable of retaining information. LOGIC gene duplication, mutation and recombination may result in the diversification of Boolean logic gates. Creative thinking may sometimes require counter-intuitive reasoning, rather than common sense. Such reasoning is likely to engage novel logic circuits produced by LOGIC somatic mutations. An individual's logic maturates by a mechanism of somatic hypermutation, gene conversion and recombination of LOGIC genes in precursor cells followed by selection of neurons in the brain for functional competence. In this model, a single neuron among billions in the brain may contain a unique logic circuit being the key to a hard intellectual problem. The output of a logic neuron is likely to be a neurotransmitter. This neuron is connected to other neurons in the spiking neural network. The LOGIC gene hypothesis is testable by molecular techniques. Understanding mechanisms of authentic human ingenuity may help to invent digital systems capable of creative thinking.

Mouse models of efficient and inefficient anti-tumor immunity, with emphasis on minimal residual disease and tumor escape.

Tumor escape from the host immune response remains the major problem holding the development of immunotherapies for cancer. In this review, congenic mouse lines are discussed that differ dramatically in their ability to respond to tumors tested and, thereby, to survive or to succumb to the tumor and/or its metastases. This ability is under the control of either MHC class I or nontrivial MHC class II beta genes expressed in a small subpopulation of antigen-presenting cells. Two hypotheses can explain the results obtained so far: (1) emergence of tumor cell variants that escape the host immune response in morbid mice but are eliminated in survivors, and (2) tumor-induced immunosuppression, which is either efficient or not, depending on the congenic line used. It is argued that further experimentation on these congenics will allow to choose the correct hypothesis, and to characterize the mechanism(s) of elimination of minimal residual disease and prevention of tumor escape by the immune system of survivors as well as the reason(s) for its failure in morbid mice. It is also argued that the use of these models will substantially increase the chance to resolve the controversy of poor correlation of immunotherapy testing in mice with clinical results.