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The effect of the preparation conditions on the in vitro stability of99mTc (Sn)-pyrophosphate kit solution has been examined. To extend the shelf-life of the preparation, different methods of protection were tested. Nitrogen purging stabilizes the kit for at least 6 h after labeling when the content of99mTc-pertechnetate raises to about 5%. However, this method is ineffective in the presence of hydrogen peroxide. The protecting ability of two chemicals was also determined. Gentisic acid gave good results. In the presence of 50 g of gentisic acid per ml of the kit the content of pertechnetate was 1–2% throughout the examined time interval. To eliminate the influence of hydrogen peroxide (6 g per ml of the kit) about 100 g of gentisic acid is needed. N, N-diphenyl-p-phenylenediamine (DPPD) performs some protecting effect only when used in the samples protected by nitrogen purging. However its protecting ability is lower that in the case of gentisic acid.  相似文献   
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The possible effects of several protecting procedures on the quality of99mTc eluates were investigated. The content of99Mo in the eluates (99Mo breakthrough) was expressed in (%) with respect to the total adsorbed99Mo radioactivity and in () i.e. as the ratio of99Mo and99mTc radioactivities in each particular eluate. The radiochemical purity was expressed in (%) of99mTc(VII) in the eluates. The content of Al3+ and Cu2+ as chemical impurities was also determined.  相似文献   
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Mobilities of H+ and H? in He and in H2, and of H+2 and H+3 in He, are calculated from ion-neutral potentials derived from theory and ion-beam scattering. Agreement with experiment is reasonable except for H? in H2 and H+2 in He, which present unexplained puzzles.  相似文献   
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A general, practical and efficient one-pot synthesis of cyclic enecarbamates is described. The protocol proceeds via reduction of lactam carbamate with Super-Hydride®, followed by in situ dehydration with trifluoroacetic anhydride (TFAA) and diisopropylethylamine (DIPEA).  相似文献   
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Hepatitis B core antigen (HBcAg) expressed in Escherichia coli is able to self‐assemble into large and small capsids comprising 240 (triangulation number T = 4) and 180 (triangulation number T = 3) subunits, respectively. Conventionally, sucrose density gradient ultracentrifugation and SEC have been used to separate these capsids. However, good separation of the large and small particles with these methods is never achieved. In the present study, we employed a simple, fast, and cost‐effective method to separate the T = 3 and T = 4 HBcAg capsids by using native agarose gel electrophoresis followed by an electroelution method (NAGE‐EE). This is a direct, fast, and economic method for isolating the large and small HBcAg particles homogenously based on the hydrodynamic radius of the spherical particles. Dynamic light scattering analysis demonstrated that the T = 3 and T = 4 HBcAg capsids prepared using the NAGE‐EE method are monodisperse with polydispersity values of ~15% and ~13%, respectively. ELISA proved that the antigenicity of the capsids was not affected in the purification process. Overall, NAGE‐EE produced T = 3 and T = 4 capsids with a purity above 90%, and the recovery was 34% and 50%, respectively (total recovery of HBcAg is ~84%), and the operation time is 15 and 4 times lesser than that of the sucrose density gradient ultracentrifugation and SEC, respectively.  相似文献   
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