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Biomedical subjects

M Shifman

Publications and source records attributed to M Shifman.

At least 19 recordsLinked to original sources

Supersymmetry relics in one-flavor QCD from a new 1/N expansion.

We suggest a new large-N(c) limit for multiflavor QCD. Since fundamental and two-index antisymmetric representations are equivalent in SU(3), we have the option to define SU(N(c)) QCD keeping quarks in the latter. We can then define a new 1/N(c) expansion (at a fixed number of flavors N(f)) that shares appealing properties with the topological (fixed N(f)/N(c)) expansion while being more suitable for theoretical analysis. In particular, for N(f)=1, our large-N(c) limit gives a theory that we recently proved to be equivalent, in the bosonic sector, to N=1 supersymmetric gluodynamics. Using known properties of the latter, we derive several qualitative and semiquantitative predictions for N(f)=1 massless QCD that can be easily tested in lattice simulations. Finally, we comment on possible applications for pure SU(3) Yang-Mills theory and real QCD.

Journal Article↗

The effect of gangliosides upon recovery of aspartate/glutamatergic synapses in striatum after lesions of the rat sensorimotor cortex.

Changes in neuronal uptake of glutamate/aspartate were studied in the striatum after unilateral destruction of the sensorimotor cortex and injection of GM1 ganglioside. A 75% decrease of uptake of [3H]D-aspartate in the striatum ipsilateral to the cortical lesion was detected at 10 days postlesion compared to the contralateral striatum. We have demonstrated that injection of gangliosides during 10 days returned the uptake of [3H]D-aspartate to control level and compensated loss of the synapses in the striatum after the cortical lesion and thereby can prevent aberrant axonal overgrowth in the contralateral striatum.

Animals↗

Progressive hepatic injury in prolonged parenteral alimentation.

A morphologic sequence of progressive hepatic injury is demonstrated in an immature infant who received TPN for 148 days. Because immature infants are susceptible to multiple pathophysiologic insults, it is presently impossible to isolate a single etiologic agent responsible for hepatic dysfunction. It is important for physicians caring for immature infants to establish through biochemical and morphologic monitoring that appropriate duration for TPN which is not likely to lead to irreversible hepatic injury.

Humans↗

Portability issues for a structured clinical vocabulary: mapping from Yale to the Columbia medical entities dictionary.

OBJECTIVE: To examine the issues involved in mapping an existing structured controlled vocabulary, the Medical Entities Dictionary (MED) developed at Columbia University, to an institutional vocabulary, the laboratory and pharmacy vocabularies of the Yale New Haven Medical Center. DESIGN: 200 Yale pharmacy terms and 200 Yale laboratory terms were randomly selected from database files containing all of the Yale laboratory and pharmacy terms. These 400 terms were then mapped to the MED in three phases: mapping terms, mapping relationships between terms, and mapping attributes that modify terms. RESULTS: 73% of the Yale pharmacy terms mapped to MED terms. 49% of the Yale laboratory terms mapped to MED terms. After certain obsolete and otherwise inappropriate laboratory terms were eliminated, the latter rate improved to 59%. 23% of the unmatched Yale laboratory terms failed to match because of differences in granularity with MED terms. The Yale and MED pharmacy terms share 12 of 30 distinct attributes. The Yale and MED laboratory terms share 14 of 23 distinct attributes. CONCLUSION: The mapping of an institutional vocabulary to a structured controlled vocabulary requires that the mapping be performed at the level of terms, relationships, and attributes. The mapping process revealed the importance of standardization of local vocabulary subsets, standardization of attribute representation, and term granularity.

Clinical Laboratory Information Systems↗