Hysteretic phenomena in Xe-doped C₆₀ from x-ray diffraction

Polycrystalline fullerite С₆₀ intercalated with Xe atoms at 575 K and a pressure of 200 MPa was studied by powder x-ray diffraction. The integrated intensities of a few brighter reflections have been utilized to evaluate the occupancy of the octahedral interstitial sites in С₆₀ crystals, which turned out to be (34±4) %, and in good agreement with another independent estimate. It is found that reflections of the (h00) type become observable in Xe-doped С₆₀. The presence of xenon in the octahedral sites affects both the orientational phase transition as well as the glassification process, decreasing both characteristic temperatures as well as smearing the phase transition over a greater temperature range. Considerable hysteretic phenomena have been observed close to the phase transition and the glassification temperature. The signs of the two hysteresis loops are opposite. There is reliable evidence that at lowest temperatures studied the thermal expansion of the doped crystal is negative under cool-down

Academic freedom: in justification of a universal ideal

This paper examines the justification for, and benefits of, academic freedom to academics, students, universities and the world at large. The paper surveys the development of the concept of academic freedom within Europe, more especially the impact of the reforms at the University of Berlin instigated by Wilhelm von Humboldt. Following from this, the paper examines the reasons why the various facets of academic freedom are important and why the principle should continue to be supported

Radiation therapy for nodal disease in malignant melanoma

Radiation therapy has been widely used for palliative management of inoperable metastatic malignant melanoma. For patients with nodal disease, response rates of approximately 70% have been reported. There are limited data concerning the role of adjuvant irradiation following therapeutic lymph node dissection. In this review, 57 patients with isolated resectable and nonresectable nodal disease have been treated with radiation. The overall response rate is 84% for bulky disease. Large fractions are beneficial. The median disease-free survivals were 11 months after adjuvant treatment and 7 months for those with inoperable disease. The median overall survivals were 20 months and 18 months, respectively. Local control in long-term survivors was excellent. Sixty-five percent of patients developed distant metastases. There is a need for additional studies with the use of adjuvant radiation therapy following lymph node dissection