[en] This report is based on 282 patients without prior treatment, treated with curative intention for cancer of the larynx and hypopharynx at the ENT Dept. of the Univ. of Erlangen/Nurnberg. Patients were treated with laser microsurgery plus/minus neck dissection, plus/minus postoperative radiotherapy. Low locoregional recurrences, a high adjusted survival rate, a low rate of complications and side effects, and the fact of avoiding total laryngectomy(with partial pharyngectomy) in many cases favor function preserving surgery of the primary and of the neck. Accounting for certain conditions and respecting certain limitations this concept of minimally invasive therapy represents a real progress in the treatment of cancer of the larynx and hypopharynx with respect to oncology, function and economy

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[en] Moessbauer measurements are performed on rhombohedral Y₂Fe₁₇ in the temperature range 5 to 300 K and in fields up to 20 kOe. The dipole fields and the crystalline electric field gradients are calculated for both structure types. From this a subdivision of the four crystallographically non-equivalent lattice sites into seven (eight) groups for the Th₂Zn¹⁷ (Th₂Ni¹₇) compounds is concluded, by neglecting all contributions of the asymmetry parameter. An exact allocation of the resulting subspectra to these different Fe sites is only possible for the c (f)- and a fraction of the d (g)-sites. The field and the temperature dependence of the hyperfine interactions of the distinguishable Fe sites are discussed. (author)

[en] Crystallographic and magnetic investigations of alloys with the nominal composition Gd₂(Fe sub(1-x)Ni sub(x))₁₇ are reported. Up to x=0.4 a statistical substitution of Fe by Ni atoms is possible, if at the same time an increasing excess of Gd over the stoichiometric composition is used. For 0.5<=x<=0.9, two-phase samples were obtained consisting of Gd(Fe,Ni)₅ together with either α-Fe or γ-(Fe,Ni), depending upon the value of x. The magnetic measurements show ferrimagnetic coupling between the spins of the Gd and the 3d atoms. Up to x=0.4, the shape of the mean-3d-moment vs. x curve is simular to that in the binary (Fe,Ni) system and can be explained by the filling up of the 3d bands. The influence of the conduction electrons on the mean 3d moments is small in this concentration region, but strong for Gd₂Ni₁₇, where 0.34 μsub(B) was found for a Ni atom. The curie temperatures increase with increasing x values and show a maximum for x=0.3. (Auth.)

[en] YRh₂ can be characterized as a Pauli-paramagnet. At 4 K no ordering temperatures could be detected for Y(Fe, Rh)₂ from bulk magnetic measurements, whereas at 5 K the ⁵⁷Fe Moessbauer investigations reveal magnetic hyperfine interactions. For RE = Gd, Dy, Ho a ferrimagnetic coupling is observed in the Fe substituted compounds. The Curie temperatures can be analyzed for constant x using a de Gennes function. The concentration dependence of Tsub(c) might be explained by a distance dependent Fe-Fe interaction

[en] Crystallographic and magnetic investigations on ternary alloys with the nominal composition R.E.₂(Fesub(1-x)Nisub(x))₁₇, R.E.=Y, Dy, are reported. Solid solubility was found up to x=0.5 and 0.3 for Y₂(Fe,Ni)₁₇ and Dy₂(Fe,Ni)₁₇, respectively. Single-phase samples could only be prepared by using an increasing excess of R.E. over the stoichiometric composition, with increasing Ni content. At higher Ni concentrations, an R.E.(Fe,Ni)₅ mixed crystal and α-Fe, or a γ-(Fe,Ni) alloy can be detected, depending on the nominal composition. The results of the magnetic measurements can be explained by means of a rigid-band model in analogy with the binary (Fe,Ni) alloys. The influence on the mean 3d moment of the conduction electrons contributed by the R.E. atoms is small in the mixed crystals with the Th₂Ni₁₇-type structure but strong for the binary R.E.₂Ni₁₇ compounds where a decrease of the Ni moment can be detected. The Curie temperatures increase with increasing x and show a maximum for x approximately 0.4 in the mixed crystals, Y₂(Fe,Ni)₁₇. (Auth.)

[en] Moessbauer measurement are performed on RE₂(Fesub(1-x)Cosub(x))₁₇, RE = Y, Gd, Dy compounds. The spectra are analyzed using 7 (8) subspectra for samples with Th₂Zn₁₇(Th₂Ni₁₇) structure. The differences between Fe sites, caused by the Co substitution, are neglected. A maximum value of the hyperfine field is obtained at x approximately 0.3. This agrees with the concentration dependence of the mean 3d moment and will be discussed by means of the model of two common, partially filled 3d subbands and a model involving a portion of negative exchange. From the concentration dependence of the isomer shift charge transfers to the Fe atoms may be excluded. This is supported by the results obtained for the quadrupole splittings for 0< x<0.5. For 0.5<=x<=0.9 a rotation of the easy axis into the c-direction is obtained from the ratio of the quadrupole splitting, which agrees very well with the theoretically predicted ratio of (-1) : 2. (author)

[en] Moessbauer measurements were carried out on the mixed crystal series Y(Fesub(x)Cosub(1-x))₂ in the temperature range 5 to 300 K. The direction of the electric field gradient and the values of the asymmetry parameter were calculated with the help of a point charge model. For 0.5 >= x >= 0.2 an analysis of the spectra can be performed by means of a binomial distribution and [100] as the direction of the easy magnetization. In agreement with the bulk magnetic measurements an increasing magnetic hyperfine interaction with increasing x can be observed for different Fe-positioning. For spectra with pure quadrupole interaction it is possible to make an analysis with two subspectra and a medium intensity ratio of 0.88:0.12. At low temperatures the characteristics of the spectra change strongly; it is only possible to make an analysis by the assumption of spectra with pure quadrupole interaction and those with additional hyperfine interaction. These assumptions are supported by different spectra obtained on cooling with or without an applied magnetic field but measuring in the same field. The results point to a magnetic interaction substantially influenced by the positioning of the neighbouring Fe atoms. (author)

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No abstract available