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Biomedical subjects

J Niemeyer

Publications and source records attributed to J Niemeyer.

16 recordsLinked to original sources
PubMed2002

Application of the Weibull distribution to describe the vertical distribution of cesium-137 on a slope under permanent pasture in Luxembourg.

The application of solutions of the Advection-Dispersion-Equation (ADE) for soil profiles is sometimes questionable. An alternative method, based on the Weibull distribution, has been developed, which can approximate the vertical distribution of radiocesium (137Cs) and allows extrapolation to account for the complete inventory. The structure of the equation allows simple parameters describing the soil depth profile to be derived. Reliable estimates of the total 137Cs inventory can help to explain the lateral distribution. This equation was used to analyse the 137Cs-activities of Chernobyl fall-out measured on a slope under permanent pasture in Luxembourg.

Cesium Radioisotopes↗
PubMed2001

Gas-phase structures of acetyl peroxynitrate and trifluoroacetyl peroxynitrate.

The molecular structures and conformational properties of acetyl peroxynitrate (PAN, CH3C(O)OONO2) and trifluoroacetyl peroxynitrate (FPAN, CF3C(O)OONO2) were investigated in the gas phase by electron diffraction (GED), microwave spectroscopy (MW), and quantum chemical methods (HF/3-21G, HF/6-31G*, MP2/6-31G*, B3PW91/6-31G*, and B3PW91/6-311+G*). All experimental and theoretical methods show the syn conformer (C=O bond of acetyl group syn to O-O bond) to be strongly predominant relative to the anti conformer. The O-NO2 bonds are extremely long, 1.492(7) A in PAN and 1.526(10) A in FPAN, which correlates with their low bond energy and the easy formation of CX3C(O)OO* and *NO2 radicals in the atmosphere. The O-O bonds (1.418(12) A in PAN and 1.408(8) A in FPAN) are shorter than that in hydrogen peroxide (1.464 A). In both compounds the C-O-O-N dihedral angle is close to 85 degrees.

Journal Article↗
PubMed2000

Suicides by sharp force: typical and atypical features.

A total of 65 consecutive cases of suicide by sharp force were investigated by evaluating the autopsy and prosecution department records. Suicides constituted 17% of all fatalities from sharp force autopsied between 1967 and 1996. Young males and persons with a psychiatric history predominated among the persons who chose this "hard" method of suicide. The most common implements used were knives (62%) and razor blades (15%). Cutting injuries in isolation were present in 26, stab injuries in isolation in 24 and a combination of both in 15 fatalities. The number of injuries per case varied from 1 to 37 but 1/3 showed one injury. More than 85% of the cutting injuries were located at the wrist, elbow crease or neck whereas 79% of the stab injuries involved the ventral aspect of the trunk. Perforation of clothing was present in 16 (52%) out of 31 stab injuries to the trunk. Injuries to more than one body region were observed in 34 (52%) cases. Tentative marks were present in 50 (77%) fatalities and the number varied from 1 to 60 per case. Superficial incisions of the fingers were found in 15% with razor blades constituting the weapon in half of these cases. Deviations from these typical patterns occurred not infrequently. The utter determination of the victim to carry it through or the use of unusual weapons resulted in a few bizarre cases which are outlined briefly.

Abdominal Injuries↗
PubMed1999

Physical activity following fatal injury from sharp pointed weapons.

Cases of suicide from sharp pointed weapons (n = 12) witnessed by one or more persons are reported with regard to the potential for physical activity. One case each involved the ulnar artery, the great saphenous vein and the periphery of the lung and liver and the physical activity following these injuries lasted for several hours. In one case, the left carotid and vertebral arteries were transected and the physical activity lasted for approximately 10 s. An extraordinary case involved a protracted incapacitation due to heart tamponade from a small myocardial injury caused by a cannula. In the remaining seven cases, a stab wound to the heart was present. With regard to the physical activity, a long-term group (2-10 min, n = 4) can be differentiated from a short-term group (approximately 10 s, n = 2) and one case of immediate incapacitation. The size of the myocardial perforation was 7-10 mm in length in the long-term group compared to 1.4-2 cm in the short-term group. So small perforations of the heart or incisions of the carotid artery offer a potential for considerable physical activity. Large perforations of the heart or a transection of the carotid and vertebral arteries can result in short-term activity.

Adult↗
PubMed1993

Collaborative practice: a shared success.

A community hospital reflects on changes made when implementing a collaborative practice theory. Using a philosophy that called both professional groups to "share and work together to provide thorough and consistent patient care," a successful joint practice was operational within a year.

Colorado↗
PubMed1992

Increased oxygen radical and eicosanoid formation in immune-mediated mesangial cell injury.

To evaluate whether monocytes/macrophages derived from glomeruli could be a source of increased eicosanoid and free oxygen radical formation in glomerular disease, monocytes/macrophage (M/M) were isolated from nephritic glomeruli and their in vitro generation of eicosanoids and superoxides were measured. Glomerular immune injury was induced by i.v. injection of a rabbit-anti-rat thymocyte antiserum (ATS). Kidneys were removed two, five, and 24 hours, and three and eight days after ATS. Adhesive glomerular macrophages were obtained by isolation of glomeruli, enzymatic digestion and incubation of the single cell suspensions in culture dishes. O2-production was evaluated by superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome C; PGE2 and TxB2 release was assessed by direct RIA. Glomerular macrophage infiltration was maximal 24 hours after intravenous antibody (35.9 +/- 5.1 M/M per glomerulus). In vitro production of superoxide was significantly enhanced (P less than 0.001) five hours after ATS administration (51.6 +/- 4.4 nmol O2/10(6) MM/hr), when compared with M/M from controls (30.4 +/- 2.0 nmol O2/10(6) MM/hr). TxB2 formation of glomerular M/M was increased (P less than 0.001) two hours and five hours after ATS administration (1056 +/- 75 and 1182 +/- 112 pg TxB2/10(6) MM/hr) compared with controls (390 +/- 34 pg TxB2/10(6) MM/hr). PGE2 synthesis, however, was decreased (P less than 0.01) at five hours after ATS (629 +/- 43 pg PGE2/10(6) MM/hr) compared with controls (950 +/- 125 pg PGE2/10(6) MM/hr). Furthermore, there was release of leukotriene B4 (LTB4) in monocytes of nephritic glomeruli five hours after ATS administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Phenomenal and operationalized classification of psychiatric disorders in children and adolescents with ICD-9 and ICD-10, on the basis of a field study.

In connection with the implementation of ICD-10, a further multicenter field study was conducted with 33 raters from 9 facilities for child and adolescent psychiatry. Each rater evaluated the same 29 case studies, resulting in a total of 957 ratings. When coding was done with 4-character ICD-10 codes interrater agreement on a given diagnosis averaged 50.3% (ICD-9: 47.3%); with 3-character ICD-10 codes the figure was 61.0% (ICD-9: 66.5%). When alternative diagnoses were also considered, agreement improved by about 7% (4-character codes) and 7.4% (3-digit codes), respectively. The highest levels of agreement were found for monosymptomatic disorders (F94, F95 and F98), the lowest for mixed disorders of conduct and emotions (F92) and depressive disorders (F31, F43). These results indicate that, on the whole, psychiatric disorders in children and adolescents can be classified reliably with the ICD-10, even when the raters have had no experience with the scheme.

Adolescent↗