For an attractive potential tail consisting of a sum of a 1/r4- and a 1/r5-term we give analytical expressions for tail parameters which determine near-threshold properties such as the reflectivity of the potential tail, the mean scattering length, the quantization rule and the level density.
For an attractive potential tail consisting of a sum of a 1/r4- and a 1/r5-term we give analytical expressions for tail parameters which determine near-threshold properties such as the reflectivity of the potential tail, the mean scattering length, the quantization rule and the level density.
We study the reflectivity of Casimir-van der Waals potentials, which behave as -C-4/r(4) at large distances and as -C-3/r(3) at small distances. The overall behavior of the reflection amplitude R depends crucially on the parameter rho=root2MC(3)/((h) over bar rootC(4)) which determines the relative importance of the -1/r(3) and the -1/r(4) parts of the potential. Near threshold, E=(h) over bar (2)k(2)/(2M)-->0, the reflectivity is given by \R\similar toexp(-2bk), with b depending on rho and the shape of the potential at intermediate distances. In the limit of large energies, ln\R\ is proportional to -k(1/3) with a known constant of proportionality depending only on C-3. For small values of rho, the reflectivity behaves as for a homogeneous -1/r(3) potential in the whole range of energies and does not depend on C-4 or the shape of the potential beyond the -1/r(3) region. For moderate and large values of rho, the reflectivity depends on C-4 and on the potential shape. For sufficiently large values of rho, which are ubiquitous in realistic systems, there is a range of energies beyond the near-threshold region, where the reflectivity shows the high-energy behavior appropriate for a homogeneous -1/r(4) potential, i.e., ln\R\ is proportional to -rootk with a proportionality constant depending only on C-4. This conspicuous and model-independent signature of the Casimir effect is illustrated for the reflectivities of neon atoms scattered off a silicon surface, which were recently measured by Shimizu [Phys. Rev. Lett. 86, 987 (2001)].
For an attractive potential tail consisting of a sum of a 1/r4- and a 1/r5-term we give analytical expressions for tail parameters which determine near-threshold properties such as the reflectivity of the potential tail, the mean scattering length, the quantization rule and the level density.
Radiolabelled granulocytes in chronic inflammatory bowel diseases (CIBD) are able to diagnose the disease extent and assess the disease activity. It may be performed with 111In oxine- and 99Tcm hexamethylpropyleneamineoxime (HMPAO)-labelled cells. The granulocyte scan localizes inflamed bowel segments with an accuracy comparable with radiology and endoscopy including biopsy of the bowel (r = 0.95; P less than 0.001). The specificity of the scan for diseased segments is near 100%, the sensitivity 92%. A three-phase white blood cell scan (imaging: 0.5, 4, 20 h post injection) allows differentiation of diseased bowel segments from abscesses and fistulas. False positive results are possible in necrotic carcinomas. The 99Tcm HMPAO scan shows rapid renal and delayed biliary and intestinal excretion of tracer. In this way diagnostic problems arise in the small pelvis. Because of the intestinal and biliary excretion, early images should be obtained (0.5-2 h post injection). Later scans with 99Tcm HMPAO are of minor importance. The disease activity can very specifically be assessed by the determination of the percentage faecal 111In excretion (96 h faecal collection). Active and non-active diseases can be clearly differentiated. We found no correlation with the subjectively influenced Crohn's disease activity index (CDAI) (r = 0.25; P greater than 0.05), but good correlations with the Dutch Index (van Hees: r = 0.67), ESR (r = 0.69), serum albumin (r = -0.54) and orosomucoid (r = 0.65). The percentage faecal excretion correlates well with the histologically estimated leucocytic bowel infiltration. Because of the intestinal 99Tcm HMPAO excretion the determination of faecal excretion is pointless in 99Tcm studies.(ABSTRACT TRUNCATED AT 250 WORDS)
Bericht über 46 Kinder, von denen etwa die Hälfte mit Vitamin D2, die andere mit D3-Konzentrat behandelt wurde. Im Vergleich weder klinisch, noch röntgenologisch, noch blutchemisch ein greifbarer Unterschied.
