Investigation of Design Space for Freeze-Drying: Use of Modeling for Primary Drying Segment of a Freeze-Drying Cycle

In this work, we explore the idea of using mathematical models to build design space for the primary drying portion of freeze-drying process. We start by defining design space for freeze-drying, followed by defining critical quality attributes and critical process parameters. Then using mathematical model, we build an insilico design space. Input parameters to the model (heat transfer coefficient and mass transfer resistance) were obtained from separate experimental runs. Two lyophilization runs are conducted to verify the model predictions. This confirmation of the model predictions with experimental results added to the confidence in the insilico design space. This simple step-by-step approach allowed us to minimize the number of experimental runs (preliminary runs to calculate heat transfer coefficient and mass transfer resistance plus two additional experimental runs to verify model predictions) required to define the design space. The established design space can then be used to understand the influence of critical process parameters on the critical quality attributes for all future cycles.     

Locating the broad-spectrum wheat leaf rust resistance gene Lr52 (LrW) to chromosome 5B by a new cytogenetic method

This study was conducted to genetically map a potentially new wheat leaf rust resistance gene (LrW) using a novel genetic method and to test its effectiveness against current races of leaf rust (Puccinia triticina Eriks.) in Canada. Undoubled haploids of a near-isogenic line of Thatcher carrying the resistance gene (RL6107) were pollinated with a contrasting susceptible cultivar to generate an array of hybrids with random deficiencies arising from irregular meiosis of the haploid. Genetic analysis of the deficiencies in such populations can be used to locate qualitative traits by which the two parents differ through a process that we have called haploid deficiency mapping. In the present case, 5/417 hybrids were both susceptible to leaf rust (i.e. lacked the resistance gene) and also lacked several polymorphic microsatellite alleles from RL6107 that are specific to chromosome 5B. This correlated failed transmission of the resistance gene and deficiency for chromosome 5B. Analysis of an F₂ population showed that the factor conditioning resistance was located on the short arm of 5B, 16.5 cM distal to the locus of the microsatellite Xgwm443. Since no other leaf rust resistance genes have been mapped to this region, LrW was re-designated Lr52. RL6107 was tested with 29 isolates of P. triticina, encompassing a diversity of virulence found in North America, with none showing virulence. The effectiveness and novelty of Lr52 make it a promising source of resistance for North American wheat cultivars.     

A radioimmunoprecipitation method in the serodiagnosis of HIV infection: the development of the optimal conditions for its performance and the evaluation of the possibilities for its use

The optimum conditions for using the method of radioimmunoprecipitation (RIP) for the detection of human immunodeficiency virus (HIV) in serum samples have been established. Out of several available cell lines persistently infected with HIV, specially selected line 17 has been chosen. The characteristic feature of this is the high and stable (under the conditions of prolonged cultivation) accumulation of virus-specific proteins in infected cells. The optimum conditions for making the test and its evaluation have also been established. The data of literature on the advantages of the method of RIP over such traditional methods as the enzyme immunoassay and immunoblotting have been confirmed. Thus, the presence of specific antibodies in several serum samples registered as false negative has been established. The intertypical reactivity of two serotypes of the virus, HIV-1 and HIV-2, has been studied. Cross reactivity of antibodies with respect to the HIV gene gag, but not with respect to viral glycoproteids, has been established. Ideas on the expediency and prospects of using RIP for the serological control of HIV infection are presented.