ABSTRACT
The recent availability of large volume cerium bromide crystals raises the possibility of substantially improving gamma-ray spectrometer limiting flux sensitivities over current systems based on the lanthanum tri-halides, e.g., lanthanum bromide and lanthanum chloride, especially for remote sensing, low-level counting applications or any type of measurement characterized by poor signal to noise ratios. The Russian Space Research Institute has developed and manufactured a highly sensitive gamma-ray spectrometer for remote sensing observations of the planet Mercury from the Mercury Polar Orbiter (MPO), which forms part of ESA's BepiColombo mission. The Flight Model (FM) gamma-ray spectrometer is based on a 3-in. single crystal of LaBr3(Ce(3+)) produced in a separate crystal development programme specifically for this mission. During the spectrometers development, manufacturing, and qualification phases, large crystals of CeBr3 became available in a subsequent phase of the same crystal development programme. Consequently, the Flight Spare Model (FSM) gamma-ray spectrometer was retrofitted with a 3-in. CeBr3 crystal and qualified for space. Except for the crystals, the two systems are essentially identical. In this paper, we report on a comparative assessment of the two systems, in terms of their respective spectral properties, as well as their suitability for use in planetary mission with respect to radiation tolerance and their propensity for activation. We also contrast their performance with a Ge detector representative of that flown on MESSENGER and show that: (a) both LaBr3(Ce(3+)) and CeBr3 provide superior detection systems over HPGe in the context of minimally resourced spacecraft and (b) CeBr3 is a more attractive system than LaBr3(Ce(3+)) in terms of sensitivities at lower gamma fluxes. Based on the tests, the FM has now been replaced by the FSM on the BepiColombo spacecraft. Thus, CeBr3 now forms the central gamma-ray detection element on the MPO spacecraft.
ABSTRACT
Hydrogen has been inferred to occur in enhanced concentrations within permanently shadowed regions and, hence, the coldest areas of the lunar poles. The Lunar Crater Observation and Sensing Satellite (LCROSS) mission was designed to detect hydrogen-bearing volatiles directly. Neutron flux measurements of the Moon's south polar region from the Lunar Exploration Neutron Detector (LEND) on the Lunar Reconnaissance Orbiter (LRO) spacecraft were used to select the optimal impact site for LCROSS. LEND data show several regions where the epithermal neutron flux from the surface is suppressed, which is indicative of enhanced hydrogen content. These regions are not spatially coincident with permanently shadowed regions of the Moon. The LCROSS impact site inside the Cabeus crater demonstrates the highest hydrogen concentration in the lunar south polar region, corresponding to an estimated content of 0.5 to 4.0% water ice by weight, depending on the thickness of any overlying dry regolith layer. The distribution of hydrogen across the region is consistent with buried water ice from cometary impacts, hydrogen implantation from the solar wind, and/or other as yet unknown sources.
Subject(s)
Moon , Extraterrestrial Environment , Hydrogen , Spectrum AnalysisABSTRACT
Combined approach (surgery and chemotherapy) have been acknowledged as the optimal treatment scheme in oncology. The purpose of this case study was to detect and compare the changes in metabolism emerging in combined treatment method for the purpose of working out, later, a therapeutic correction scheme to correct such changes. Two groups of patients, 20 subjects in each, were examined to establish a basic higher degree of the protein-and-energetic insufficiency and a changed immune response, due to which metabolism in patients with combined treatment normalizes slower than in patient with surgical treatment. Special scheme, worked out for the purpose, are needed to correct the progressing lesions.
Subject(s)
Gastrectomy/methods , Protein-Energy Malnutrition/metabolism , Proteins/metabolism , Stomach Neoplasms/metabolism , Aged , Blood Proteins/analysis , Body Composition , Combined Modality Therapy , Energy Metabolism , Female , Humans , Male , Middle Aged , Nutritional Status , Protein-Energy Malnutrition/blood , Protein-Energy Malnutrition/etiology , Stomach Neoplasms/blood , Stomach Neoplasms/radiotherapy , Stomach Neoplasms/surgeryABSTRACT
In patients with diffuse purulent peritonitis, the total pool of an acid-soluble blood plasma fraction (ABPF) considerably increases as compared to that in normals (donors). The present paper is concerned with the role of proteolytic activity and lysis of bacterial cells and cells of different human tissues in the formation of the ABPF in patients with peritonitis. For this purpose the normals' blood and its separate components were treated with various enzymes (trypsin, pronase, chemotrypsin, papain, elastase, alpha-amylase) to measure the ABPF. The pattern of changes detectable on such a treatment was compared with the tendency of changes seen in patients with peritonitis. Measurements were also made of acid-soluble fractions in suspensions of bacterial cells and cells of the pancreas, liver and heart muscle tissue of man. It has been found that on proteolysis of plasma proteins and membrane proteins of blood cells there form products contained by the ABPF. Such products formed in the greatest amount as a result of treatment with pronase. Products of the lysis of bacterial cells may be also contained by the ABPF of peritonitis patients. The possibility of detecting proteolytic degradation and cellular disintegration according to the spectral characteristics of separate fractions of the ABPF is discussed.