Single vial kit formulation for preparation of PET radiopharmaceutical: 68Ga-DOTA-TOC

This paper describes the development of a lyophilized cold kit of DOTA-[Tyr³]-Octreotide (DOTA-TOC) for instant compounding of ⁶⁸Ga-DOTA-TOC, suitable for diagnosis of neuroendocrine tumors. The work involved formulation of DOTA-TOC kits, optimization of radiolabeling, quality control of ⁶⁸Ga-DOTA-TOC and animal biodistribution studies. The prepared kits enable a reliable method for preparation of ⁶⁸Ga-DOTA-TOC of high radiochemical purity and excellent stability. Availability of such kits along with ⁶⁸Ge/⁶⁸Ga generators is expected to stimulate the widespread use of ⁶⁸Ga-DOTA-TOC in nuclear medicine practice in developing countries.     

Nano-crystalline zirconia: a viable adsorbent for the column chromatographic separation of 58Co from neutron irradiated nickel targets

Owing to the high chemical reactivity of molten uranium alloys, the use of traditional graphite crucibles for casting fuel slugs for a sodium-cooled fast reactor (SFR) is problematic. Moreover, rare earth (RE) elements retained in the fuel slugs for an SFR, which are extracted from the spent fuel by pyro-processing, are more reactive than uranium melt. Therefore, in this study, Y₂O₃ single-layer coatings with thicknesses of approximately 50, 70, and 120 μm and double-layer coatings of TaC/Y₂O₃ and Y₂O₃/TaC were plasma-sprayed onto niobium substrates and tested for thermal shock resistance and compatibility against U–10 wt% Zr and U–10 wt% Zr–5 wt% RE melt. The Y₂O₃ single-layer coating, regardless of coating thickness, and the TaC/Y₂O₃ double-layer coating showed good contact at the interface between the coating and the niobium substrate, with no deterioration after the thermal cycling test. In the interaction studies, the single- and double-layer coatings showed good compatibility with the U–Zr melt. However, the Y₂O₃ coatings with thicknesses of approximately 50 and 70 μm showed severe penetration of the U–Zr–RE melt and reacted with the niobium substrate. The single-layer Y₂O₃ coating with a thickness of 120 μm and the double-layer TaC/Y₂O₃ coating exhibited the most promising performance among the candidate coatings.     

Magnetic field studies of the frictional drag between coupled two-dimensional electronic systems – Coulomb versus phonon coupling

The coupling between systems of two spatially separated two-dimensional (2D) electron gases and between systems of a separated 2D electron gas and a 2D hole gas is studied as a function of magnetic field . The small barrier (30 nm) separated coupled electron gases showed a transition from a phonon dominated interaction at to a Coulomb dominated one at quantising fields. For large barriers (190 nm) phonons have been found to be the dominant coupling mechanism both at zero and finite fields. However, for all barriers investigated we could observe novel screening effects manifested in a suppression of the coupling at half-filled Landau levels. For the coupled electron–hole gases we have investigated samples with large barriers ( ) so that the coupling is both in zero and finite fields dominated by phonon mediated processes. The enhanced screening effects could not be observed in those samples possibly due to the less pronounced quantisation of the hole gas.     

Coherence of some rings of functions

To say that a commutative ring $\text{R}$ with unit is coherent amounts to saying, in case $\text{R}$ has no divisors of zero, that the intersection of two finitely generated ideals in $\text{R}$ is finitely generated. We prove that the ring H^∞ of bounded analytic functions in the unit disc is coherent, while the disc algebra A is not coherent. For any positive measure μ, L^∞(μ) is coherent.     

Stochastic competitive entries and dynamic pricing

How should firms price new products when they do not know the timing, nor the nature of the next competitive entry? To guide managers’ pricing decisions in such contexts, we propose a dynamic pricing model with two types of randomly timed entry, i.e. imitative and innovative. The characterization of the equilibrium strategies reveals how optimal prices vary with the manager’s knowledge about the timing of future competitive entries. We show that price skimming is not always optimal when entry dates are unknown to managers. Everything else equal, we demonstrate that the randomness of competitive entries make forward looking managers to choose constant prices, even though the characteristics of the market would have justified skimming the demand in the normal course. Moreover, we show that the constant pricing policy remains optimal even when the incumbent’s optimal pricing strategy influences the probability of facing a competitive entry. Finally, we find that uncertainty does not necessarily hurt firms’ profits.     

An Alumina Based 99Mo–99mTc Generator to Produce 99mTc in Organic Medium Suitable for Industrial Radiotracer Applications

An industrial chromatographic ⁹⁹Mo–^99mTc generator has been developed with the aid of chromatographic alumina to obtain ^99mTc in a non-aqueous medium. This generator system takes advantage of tributyl phosphate to extract ^99mTc selectively with appreciable yield and in high radiochemical and radionuclidic purity. This facile, versatile and efficient approach provides ^99mTc at industrial sites in a medium soluble in hydrocarbon solvents, for radiotracer applications.     

Very slowly varying functions

A real-valued functionf of a real variable is said to be?-slowly varying (?-s.v.) if lim _x→∞ ?(x) [f(x+α)?f(x)]=0 for each α. It is said to be uniformly?-slowly varying (u.?-s.v.) if lim _x→∞ sup _{α ∈ I} ?(x) |f(x+α)?f(x)|=0 for every bounded intervalI. It is supposed throughout that ? is positive and increasing. It is proved that if? increases rapidly enough, then every?-s.v. functionf must be u.?-s.v. and must tend to a limit at ∞. Regardless of the rate of increase of?, a measurable functionf must be u.?-s.v. if it is?-s.v. Examples of pairs (?,f) are given that illustrate the necessity for the requirements on? andf in these results.