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OBJECTIVE: To investigate the active compounds from Saussurea involucrata on the heart and brain of mice at simulated high altitude. METHODS: Fifty healthy male adult BALB/c mice were randomly divided into normal control group, hypoxic model group, acetazolamide group, petroleum ether extract of Saussurea involucrata (PESI) group and octacosan group with 10 mice in each group. Acetazolamide group, PESI group and octacosan group were treated with acetazolamide (200 mg/kg), PESI (200 mg/kg) or octacosan (100 mg/kg) by single tail vein injection, respectively. Except normal control group, the mice were exposed to a simulated high altitude of 6000 m for 8 h in an animal decompression chamber. After the mice were sacrificed by cervical dislocation, the heart and brain were histologically observed by HE staining; superoxide dismutase (SOD) activity, total anti-oxidant capacity (T-AOC) and the content of malondialdehyde (MDA) in plasma, heart and brain tissues were detected by WST-1 method, ABTS method and TBA method, respectively; lactic acid and lactate dehydrogenase (LDH) activity in plasma, heart and brain tissues were detected by colorimetric method and microwell plate method, respectively; ATP content and ATPase activity in heart and brain tissues were detected by colorimetric method. RESULTS: PESI and octacosane significantly attenuated the pathological damages of heart and brain tissue at simulated high altitude; increased SOD activity, T-AOC and LDH activity, and decreased the contents of MDA and lactic acid in plasma, heart and brain tissues; increased the content of ATP in heart and brain tissues; increased the activities of Na (+)-K (+) ATPase, Mg (2+) ATPase, Ca (2+) ATPase and Ca (2+)-Mg (2+) ATPase in myocardial tissue; and increased the activities of Mg (2+) ATPase, Ca (2+)-Mg (2+) ATPase in brain tissue. CONCLUSION: PESI and octacosan exert anti-hypoxic activity by improving the antioxidant capacity, reducing the free radical levels, promoting the anaerobic fermentation, and alleviating the energy deficiency and metabolic disorders caused by hypoxia in mice.

The Houtman Sub-basin lies adjacent to the Wallaby-Zenith Transform Margin, an under-explored region of Australia’s continental margin located at the transition between the non-volcanic margin of t...

SUMMARY Traditional methods for processing low magnetic latitude data below ±25° magnetic latitude do not fully resolve anomaly location and may distort the anomaly shape leading to misinterpretation of the data, as well as loss of certain directional anomalies. The principal objective of our research was to develop a new filter that would better position anomalies, reduce anomaly distortion and provide good anomaly shape while attempting to recover structures parallel to the declination direction. The MTC-LML Filter (Modulus of Total Component at low magnetic latitudes) is based on the calculation of the Modulus of the three magnetic components of the main field (one vertical and two orthogonal horizontal). To test the MTC-LML Filter, a set of synthetic models were constructed composed of complicated magnetic bodies each with different strike directions and depths. Each model was designed to address a specific aspect of the low magnetic latitude problem. The results of synthetic modelling for the MTC-LML Filter were compared with synthetic models of standard transformations and techniques for dealing with low magnetic latitude data. Practical applications of the MTC-LML Filter were then made using survey data. The filter results for synthetic model and survey data, show better location and shape of model source bodies when compared to the existing standard transformations and techniques. The MTC-LML Filter provides an improved transformation of the data with reliable location and shape of the anomalies above the source, reduced anomaly distortion and better recovery of structure parallel to the declination direction.

Two types of filters have been developed for the purpose of enhancing weak magnetic anomalies from near-surface sources while simultaneously enhancing low-amplitude, long-wavelength magnetic anomalies from deep-seated or regional sources. The Edge filter group highlights edges surrounding both shallow and deeper magnetic sources. The results are used to infer the location of the boundaries of magnetised lithologies. The Block filter group has the effect of transforming the data into ``zones' which, similar to image classification systems, segregate anomalous zones into apparent lithological categories. Both filter groups change the textural character of a dataset and thereby facilitate interpretation of geological structures. The effect of each filter is demonstrated using theoretical model studies. The models include both shallow and deep sources with a range of magnetisations. Comparative studies are made with traditional filters using the same theoretical models. In order to simulate real conditions, Gaussian noise has been added to the model response. Techniques for noise reduction and geological signature enhancement are discussed in the paper. The new approaches are applied to actual magnetic survey data covering part of the Goulburn 1:100 000 scale map sheet area, New South Wales. Some new geological inferences revealed by this process are discussed.

SUMMARY The pseudo-gravity transform is one of many possible FFT techniques that can be applied to aeromagnetic data. It enhances the anomalies associated with deep magnetic sources at the expense of the dominating shallow magnetic sources. This transform is an excellent interpretation tool for the detection of deep, magnetic igneous plutons and volcanic piles and the transformed data can be modelled using conventional gravity modelling tools. It is a suitable tool for interpreting deep-seated mineral plumbing systems associated with known, shallow mineral occurrences. The pseudo-gravity transform is derived by an integration of the total magnetic intensity grid data using conventional FFT tools. Padding of the grid around the region covered by the survey introduces long wavelength artefacts into the transformed grids. These long wavelength artefacts can obscure the targets that are the object of investigation. A variety of regional residual separation procedures is applied to the transformed grid to minimise the impact of the long wavelength artifacts. The improved pseudo-gravity transform is applied to the Goulburn 1:250 000 survey in the Lachlan Fold Belt of New South Wales to demonstrate the clear separation of deep sources that are difficult to detect or understand in the context of conventional magnetic image analysis. The results are contrasted with other filter techniques. Interpretive modelling of both the magnetic and the gravity transform data show how to derive more relevant geological information from magnetic surveys. By comparing the pseudo-gravity transform results with lower resolution ground gravity data, it is possible to obtain additional geological information by analysing the correlations.

Research into the development of an expert computer system for 3D magnetic modelling has yielded a methodology that can be applied to a wide range of magnetic exploration problems. The research focussed on the development of a semi-automated method for realistic 3D modelling of magnetic units truncated by an unconformity. Using the models produced by this process it is possible to map depth variations at the unconformity surface, map irregular geological boundaries of magnetic units and estimate magnetic susceptibility values. The objective of the research was the development of an interactive tool that would allow an interpreter to select a magnetic anomaly with a mouse and have the expert system produce a complete 3D model of the magnetic source distribution. In addition, the interpreter is required to select a geological constraint that biases the model creation in a geologically plausible manner. The research required the development of an expert system that emulates the procedures used by an experienced interpreter and an inversion methodology that could resolve complex 3D objects with fuzzy geological constraints. The system had to be suitable for inclusion in popular mapping systems. For appropriate anomalies, this process replaces innumerable individual steps that are normally required to manually construct a complex 3D magnetic model. As a result it is possible to replace a lengthy manual process that may take hours with one that can take less than a minute on a desktop PC.