Third Earth Resources Technology Satellite Symposium. Volume 2: Summary of results

Summaries are provided of significant results taken from presentations at the symposium along with some typical examples of the applications of ERTS-1 data for solving resources management problems at the national, state, and local levels

Third Earth Resources Technology Satellite Symposium. Volume 3: Discipline summary reports

Presentations at the conference covered the following disciplines: (1) agriculture, forestry, and range resources; (2) land use and mapping; (3) mineral resources, geological structure, and landform surveys; (4) water resources; (5) marine resources; (6) environment surveys; and (7) interpretation techniques

Scanning tunneling microscopy of deoxyribonucleic acid during replication

Scanning tunneling microscopy was used to produce topographic images of uncoated and unlabeled deoxyribonucleic acid (DNA) in air, on a graphite substrate. The images show for the first time a DNA molecule that had been isolated while it was replicating

Atomic Force Microscopy of Neuron Networks

We imaged uncoated neuron networks by an atomic force microscope in the repulsive regime of contact mode. Images of granule cells and their axons have been clearly revealed with details smaller than 20 nm. The good stability of the sample and the mechanical reproducibility of the microscope allowed the imaging of a neuron culture area of several square microns. By combining tens of images, we were able to reconstruct a highly defined neuronal network. Furthermore, the images were very reproducible over repeated scanning acquisition, demonstrating the mechanical and thermal stability of the instrument-sample system

Feasibility tests of transmission x-ray photoelectron emission microscopy of wet samples

We performed feasibility tests of photoelectron emission spectromicroscopy of wet samples in the water window (285-532 eV) soft x-ray spectral region. Water was successfully confined in an ultrahigh vacuum compatible compartment with x-ray transparent sides. This water cell was placed in the MEPHISTO spectromicroscope in a transmission geometry, and complete x-ray absorption spectra of the water window region were acquired. We also show micrographs of test samples, mounted outside of the compartment, and imaged through the water. This technique can be used to study liquid chemistry and, at least to the micron level, the microstructure of wet samples. Possibilities include cells in water or buffer, proteins in solution, oils of tribological interest, liquid crystals, and other samples not presently accessible to the powerful x-ray photoelectron emission spectromicroscopy technique

Does the term 'trophic' actually mean anti-amyloidogenic? The case of NGF.

The term trophic is widely used to indicate a general pro-survival action exerted on target cells by different classes of extracellular messengers, including neurotrophins (NTs), a family of low-molecular-weight proteins whose archetypal member is the nerve growth factor (NGF). The pro-survival action exerted by NTs results from a coordinated activation of multiple metabolic pathways, some of which have only recently come to light. NGF has been shown to exert a number of different, experimentally distinguishable effects on neurons, such as survival, differentiation of target neurons, growth of nerve fibers and their guidance (tropism) toward the source of its production. We have proposed a more complete definition of the NGF trophic action that should also include its newly discovered property of inhibiting the amyloidogenic processing of amyloid precursor protein (APP), which is among the first hypothesized primary trigger of Alzheimer's disease (AD) pathogenesis. This inhibitory action appears to be mediated by a complex series of molecular events and by interactions among NGF receptors (TrkA and p75), APP processing and tau metabolic fate and fun