Biomedical subjects

Michael Neumann

Publications and source records attributed to Michael Neumann.

6 recordsLinked to original sources

PubMed2003

A qualitative sampling method for monitoring water quality in temporary channels or point sources and its application to pesticide contamination.

A water-sampling device to monitor the quality of water periodically and temporarily flowing out of concrete tubes, sewers or channels is described. It inexpensively and easily enables a qualitative characterization of contamination via these point-source entry routes. The water sampler can be reverse engineered with different sizes and materials, once installed needs no maintenance, passively samples the first surge, and the emptying procedure is short. In an agricultural catchment area in Germany we monitored an emergency overflow of a sewage sewer, an outlet of a rainwater sewer and two small drainage channels as input sources to a small stream. Seven inflow events were analysed for 20 pesticide agents (insecticides, fungicides and herbicides). All three entry routes were remarkably contaminated. We found parathion-ethyl concentrations of 0.3 microg l(-1), diuron up to 17.3 microg l(-1), ethofumesate up to 51.1 microg l(-1), metamitron up to 92 microg l(-1) and prosulfocarb up to 130 microg l(-1).

Engineering↗

PubMed2002

The significance of entry routes as point and non-point sources of pesticides in small streams.

In an agricultural catchment area in Germany we analyzed water samples from five entry routes for 2 insecticides. 5 fungicides and 13 herbicides. The sewage plant outlet and the emergency overflow of a sewage sewer contained only herbicides. In each farmyard runoff we found on average 24 g pesticides during application period, presumably caused by cleaning the spraying equipment. In comparison, the field runoff and the rainwater sewer contained less load, but also insecticides, fungicides and herbicides. The sewage plant caused 65.9% of the total herbicide load, the sewage sewer 19.8% and the farmyard runoff 12.8%. The farmyards also caused 83.7% of total insecticide and 83.8% of fungicide load. The total load of all entry routes is correlated with the amount of pesticides applied in the catchment area and the Ko/w value for each pesticide (mult. regress. r2: 0.82; p<0.0001; n = 14). In stream A the sewage plant caused a slight but continuous contamination by herbicides with 82% of the total load found during low-water phases. In comparison, stream B had only farmyard runoff and non-point sources, which caused high peaks of herbicide and a contamination by insecticides. Consequently, high-water phases generated 70% of the total pesticide load.

Agriculture↗

PubMed2002

The impact of agricultural runoff on stream benthos in Hong Kong, China.

We investigated three small streams in the New Territories of Hong Kong, China. In each stream, we compared the benthic macroinvertebrate fauna of one site immediately upstream of an area of agricultural land (market gardening) with a second site immediately downstream. Each pair of sites was < 300 m apart. Samples were taken at the end of the dry season (March 2000) and again (April 2000) just after heavy rainfall had caused runoff from the fields. The total number of taxa at the downstream sites was the same as that in the upstream sites in March. In April, the total taxon richness was lower at the downstream localities although this difference was statistically significant in only one stream. The acute toxic effect of runoff became clearer when focusing on the group of sensitive benthic fauna. The grouping was done by ranking the relatively physiological tolerance to organotoxins following the relevant literature (Bull. Environ. Contam. Toxicol. 67 (2001) 360). All streams showed a significant downstream decrease in the number of sensitive taxa in April, while in two of three streams the number of relatively tolerant taxa increased. Ordination (by n-MDS) confirmed this pattern. It revealed a marked temporal trend in all streams resulting from a decrease of sensitive taxa downstream that was not apparent at the upstream sites. The size of the observed effects varied among streams, and may have reflected differences in the composition of the agricultural runoff.

Agriculture↗

PubMed2002

DICOM--current status and future developments for radiotherapy.

Today, DICOM is one of the most successful standards in medicine. The standard was developed based on the increasing need for the transfer of digital images between systems of different vendors. Furthermore these images needed to be archived in a system independent format. DICOM has been continuously evolving since the early 80s and is today the main standard in radiology. After the IEC had started an initiative to develop a communication standard for radiotherapy in the late 80s, they joined forces with the DICOM Committee. This led to the foundation of a new working group (Working Group 7--Radiotherapy Objects) that deals with the radiotherapy extensions of DICOM. In 1997 and 1999 the so-called RT extension of DICOM was published, containing seven new objects and related services. Since then all major vendors of systems for radiotherapy have implemented DICOM interfaces that support the DICOM RT extensions. Working Group 7 is currently working on extending the Workflow support for the RT objects. This extension will increase the available services and will improve the handling of DICOM RT data. The developments so far are encouraging and it is hoped that DICOM will be as indispensable in radiotherapy as in radiology.

Germany↗

PubMed2002

Determination of the subcellular distribution of mercaptoundecahydro-closo-dodecaborate (BSH) in human glioblastoma multiforme by electron microscopy.

The subcellular distribution of mercaptoundecahydro-closo-dodecaborate (BSH) in glioblastoma multiforme tissue sections of several patients having received BSH prior to surgery was investigated by transmission electron microscopy (TEM) using antibodies against BSH and electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI). These microscopic techniques show that BSH is associated with extracellular structures, the cell membrane as well as with the chromatin in the nucleus.

Borohydrides↗

PubMed2002

Simple method for reduction of autofluorescence in fluorescence microscopy.

Autofluorescence of aldehyde-fixed neural tissue often complicates the use of fluorescence microscopy. Background fluorescence can be notably reduced or eliminated by irradiation with light before treatment with fluorescence probes, resulting in a higher contrast without adversely affecting the staining probabilities.

Animals↗