Initial measurement of the intracellular glass transition of a mammalian cell type under cryopreservation conditions

A key physical event during the cooling of cells is the temperature at which the intracellular compartment undergoes vitrification. Recently (http://dx. doi.org/10.1371/journal.pone.0066207) we have measured the intracellular glass transition temperature (Tg) of bacteria using differential scanning calorimetry (DSC). Here we report the first data on the intracellular Tg of a mammalian cell cooled with and without a cryoprotectant (Me2SO). Jurkat cells (an immortalized T cell line) were concentrated and a pellet of approximately 30 mg cooled in a DSC, SnowMax was added to induce ice nucleation. On warming an intracellular glass transition was detected by the deviation in the first derivative of the heat flow, associated with a change in heat capacity as the cells devitrify at Tg. The transition temperature measured by DSC is Tg', that is the Tg of the maximally freezeconcentrated intracellular matrix. In the presence of Me2SO intracellular Tg was measured to be - 40 C, in controls (no Me2SO) Tg occurred at higher temperatures. In further experiments the temperature of the lipid phase transitions were analyzed by FTIR, and were measured to occur above freezing temperatures. The implications of the measured values of Tg’ for the basic cryobiology of mammalian cells will be discussed

Less is more

A code generator is a program translating an input model into code. In this paper we focus on template-based code generators in the context of the model view controller architecture (MVC). The language in which the code generator is written is known as a metalanguage in the code generation parlance. The metalanguage should be, on the one side, expressive enough to be of practical value, and, on the other side, restricted enough to enforce the separation between the view and the model, according to the MVC. In this paper we advocate the notion of unparser-complete metalanguages as providing the right level of expressivity. An unparsercomplete metalanguage is capable of expressing an unparser, a code generator that translates any legal abstract syntax tree into an equivalent sentence of the corresponding context-free language. A metalanguage not able to express an unparser will fail to produce all sentences belonging to the corresponding context-free language. A metalanguage able to express more than an unparser will also be able to implement code violating the model/view separation. We further show that a metalanguage with the power of a linear deterministic tree-to-string transducer is unparser-complete. Moreover, this metalanguage has been successfully applied in a nontrivial case study where an existing code generator is refactored using templates

A framework for extended algebraic data types

10.1007/11737414_5Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)3945 LNCS47-6