Prediction of chromatographic retention and protein identification in liquid chromatography/mass spectrometry

Liquid chromatography coupled on- or off-line with mass spectrometry is rapidly advancing as a tool in proteomics capable of dealing with the inherent complexity in biology and complementing conventional approaches based on two-dimensional gel electrophoresis. Proteins can be identified by proteolytic digestion and peptide mass fingerprinting or by searching databases using short-sequence tags generated by tandem mass spectrometry. This paper shows that information on the chromatographic behavior of peptides can assist protein identification by peptide mass fingerprinting in liquid chromatography/mass spectrometry. This additional information is significant and already available at no extra experimental cost.     

Uzawa Conjugate Gradient Domain Decomposition Methods for Coupled Stokes Flows

This paper deals with nonoverlapping domain decomposition methods for two coupled Stokes flows, based on the duality theory. By introducing a fictitious variable in the transmission condition and using saddle-point equations, the problem is restated as a linearly constrained maximization problem. According to whether constraints are uncoupled Stokes problems or uncoupled Poisson problems, two Uzawa-type domain decomposition algorithms are proposed. The results of some numerical experiments on a model problem are given.     

Abstraction paradigms for computer graphics

In computer graphics we use techniques from different areas of mathematics. Mathematical models are used to simulate real-world objects, as well as natural phenomena. In order to understand these models and pose relevant problems in each particular field of this area, it is important to create levels of abstraction. These levels encapsulate common properties of the different models and allow us to have a global, conceptual view of the methods and techniques in each field. In this paper we study a paradigm for creating abstraction levels that can also be used to characterize more general problems in computational applied mathematics. We apply this paradigm to different areas of computer graphics: modeling, animation, illumination, color theory, image processing and human-computer interface.     

Neurological protection during cardiopulmonary bypass/deep hypothermia

OBJECTIVE: To determine if arthroscopic synovectomy in normal and inflamed joints had temporal or site-related effects on articular cartilage. STUDY DESIGN: Alterations in equine third carpal bone articular cartilage were studied at two time periods: groups 1 and 2 (6 weeks) and groups 3 and 4 (2 weeks) after synovectomy in normal (groups 2 and 4) and inflamed carpi (groups 1 and 3). ANIMAL POPULATION: 16 carpi from eight horses. METHODS: Biochemical and biomechanical properties of dorsal and palmar articular cartilage were determined by radioloabeling, proteoglycan (PG) extraction, chromatography, electrophoresis, and indentation testing. RESULTS: Synovectomy in inflamed joints produced the greatest concentration of newly synthesized PG in articular cartilage by 2 weeks. Synovectomy in normal joints produced significantly greater newly synthesized PG in articular cartilage by 6 weeks. Dorsal sites had greater newly synthesized and endogenous PG in some groups. Chromatographic profiles of newly synthesized PG demonstrated early and late PG peaks. Electrophoresis of late PG peak showed a toluidine blue-positive band that comigrated with human A1D1 PG monomer in the two groups with the most newly synthesized PG> This band was reactive with monoclonal antibody 1C6 specific for the hyaluronic acid-binding region of aggrecan. For the material properties evaluated, only Poisson's ratio was significantly decreased between groups as a function of time (6 weeks < 2 weeks). and this was most pronounced in the thicker dorsal sites. CONCLUSIONS: Synovectomy in inflamed joints produced site-specific, significantly greater responses in articular cartilage as compared with synovectomy in normal joints. CLINICAL RELEVANCE: Synovectomy may not be beneficial to the articular cartilage in inflamed joints.     

Dynamic strain aging and hydrogen-induced softening in alpha titanium

Compression tests were carried out on samples of commercial-purity titanium charged with up to 4.7 at. pct hydrogen. Strain rates of 10⁻³ to 1 s⁻¹ were employed and testing was limited to the α phase field at temperatures of 773 to 973 K. The dependences of the flow stress on strain, strain rate, and temperature were determined. A plateau or bulge appeared in the temperature and strain-rate dependences of the flow stress, and the work-hardening rate also showed peaks. Serrations were observed on some of the stress-strain curves. All these features indicated that dynamic strain aging (DSA) was occurring. Analysis of the results (together with data from other authors) indicates that there are three ranges of DSA behavior in this material within the experimentally investigated temperature range; these appear to be associated with the diffusion of iron, carbon, and oxygen, respectively. Alloying with hydrogen decreases the magnitude of the DSA attributable to these elements and displaces the phenomenon to higher temperatures and/or to lower strain rates. The dependence on strain rate and temperature of the relative softening attributable to hydrogen addition was determined. The results indicate that hydrogen-induced softening is related to the occurrence of DSA in this temperature range. Possible explanations for this relationship are discussed. O.N. SENKOV, on leave from the Institute of Solid State Physics, Russian Academy of Sciences, Moscow Region 142432, Russia     

Results of reconstructive surgery in renal hypertension]

A traumatic macular hole has never been seen immediately after the causal accident. We examined a case of macular hole within half an hour of the injury and photographed it within three hours. We comment on the genesis of traumatic macular edema.