Investigation of sialylation aberration in N-linked glycopeptides by lectin and tandem labeling (LTL) quantitative proteomics

The accuracy in quantitative analysis of N-linked glycopeptides and glycosylation site mapping in cancer is critical to the fundamental question of whether the aberration is due to changes in the total concentration of glycoproteins or variations in the type of glycosylation of proteins. Toward this goal, we developed a lectin-directed tandem labeling (LTL) quantitative proteomics strategy in which we enriched sialylated glycopeptides by SNA, labeled them at the N-terminus by acetic anhydride ((1)H(6)/(2)D(6)) reagents, enzymatically deglycosylated the differentially labeled peptides in the presence of heavy water (H(2)(18)O), and performed LC/MS/MS analysis to identify glycopeptides. We successfully used fetuin as a model protein to test the feasibility of this LTL strategy not only to find true positive glycosylation sites but also to obtain accurate quantitative results on the glycosylation changes. Further, we implemented this method to investigate the sialylation changes in prostate cancer serum samples as compared to healthy controls. Herein, we report a total of 45 sialylated glycopeptides and an increase of sialylation in most of the glycoproteins identified in prostate cancer serum samples. Further quantitation of nonglycosylated peptides revealed that sialylation is increased in most of the glycoproteins, whereas the protein concentrations remain unchanged. Thus, LTL quantitative technique is potentially an useful method for obtaining simultaneous unambiguous identification and reliable quantification of N-linked glycopeptides.     

Experimental Investigation of Heat Transfer Enhancement in Rectangular Duct with Pentagonal Ribs

Rib turbulators are extensively used in augmentation of convective heat transfer in several applications related to heat exchange and cooling in thermal energy systems. Present experimental investigation examines the local heat transfer and friction factor characteristics of pentagonal ribs mounted on bottom heated wall of a rectangular channel. The emphasis is towards assessing and analysing the potential impact of varying chamfering angle (0 to 20°) and rib pitch to height ratio (6 to 12) on the overall heat transfer enhancement and its distribution on the surface. Experiments are performed at different Reynolds numbers ranging from 9400 to 58850. Liquid crystal thermography is applied to measure surface temperature distribution and finally to demonstrate the local heat transfer coefficient over the ribbed surface. The results depict that the local augmentation Nusselt number distribution is axisymmetric and shows 2-dimensionalty in heat transfer distribution. Pentagonal ribs show a significant improvement for the low heat transfer zones in leeward vicinity of the square rib, specially prominent at higher Reynolds number, and therefore seen as the potential benefit in terms of obviating the hotspots. It is observed that the pentagonal ribs lead to superior heat transfer enhancement in conjunction with significant reduction in pressure penalty as compared to square ribs and thus ensures an enhanced thermo-hydraulic performance.     

Genetic analysis of Fourier transform infrared milk spectra in Danish Holstein and Danish Jersey

Fourier transform infrared milk spectral data are routinely used for milk quality control and have been revealed to be driven by genetics. This study aimed to (1) estimate heritability for 1,060 wavenumbers in the infrared region from 5,008 to 925 cm^?1, (2) estimate genomic correlations between wavenumbers with increased heritability, and (3) compare results between Danish Holstein and Danish Jersey cows. For Danish Holstein, 3,275 cows and 19,656 milk records were available. For Danish Jersey, 3,408 cows and 20,228 milk records were available. We used a hierarchical mixed model, with a Bayesian approach. Heritability of individual wavenumbers ranged from 0.00 to 0.31 in Danish Holstein, and from 0.00 to 0.30 in Danish Jersey. Genomic correlation was calculated between 15 selected wavenumbers, and varied from weak to very strong, in both Danish Holstein and Danish Jersey (0.03 to 0.97, and ?0.11 to ?0.97). Within the 15 selected wavenumbers, a subdivision into 2 groups of wavenumbers was observed, where genomic correlations were negative between groups, and positive within groups. Heritability and genomic correlations were higher in Danish Holstein compared with Danish Jersey, but followed a similar pattern in both breeds. Breed differences were most pronounced in the mid-infrared region that interacts with lactose and the spectral region that interacts with protein. In conclusion, heritability for individual wavenumbers of Fourier transform milk spectra was moderate, and strong genomic correlations were observed between wavenumbers across the spectrum. Heritability and genomic correlations were higher in Danish Holstein, with the strongest breed differences showing in spectral regions interacting with protein or lactose.     

Effect of temperature and flow nonuniformity on transient behaviour of crossflow heat exchanger

The transient temperature response of a crossflow heat exchanger is carried out using finite difference method accounting for the effect of temperature and flow nonuniformity at different input conditions. Beta flow maldistribution model has been introduced for the flow nonuniformity. The responses are found dependent on the relative position of the individual temperature streams and the position of the fluid moving device for the temperature and flow nonuniformity, respectively. Combined effect of temperature and flow nonuniformity has also been analysed and compared with the other cases.     

Extreme-Value Statistics Analysis of Fracture Strengths of a Sintered Silicon Nitride Failing from Pores

Statistical analysis and correlation between pore-size distribution and fracture strength distribution using the theory of extreme-value statistics is presented for a sintered silicon nitride. The pore-size distribution on a polished surface of this material was characterized, using an automatic optical image analyzer. The distribution measured on the two-dimensional plane surface was transformed to a population (volume) distribution, using the Schwartz–Saltykov diameter method. The population pore-size distribution and the distribution of the pore size at the fracture origin were correlated by extreme-value statistics. Fracture strength distribution was then predicted from the extreme-value pore-size distribution, using a linear elastic fracture mechanics model of annular crack around pore and the fracture toughness of the ceramic. The predicted strength distribution was in good agreement with strength measurements in bending. In particular, the extreme-value statistics analysis explained the nonlinear trend in the linearized Weibull plot of measured strengths without postulating a lower-bound strength.     

Thin films of hard cubic Zr3N4 stabilized by stress

Hard, refractory thin films consisting of group IVB element mono-nitrides deposited using various chemical and physical vapour-deposition techniques are widely used in wear-resistant applications. As the demand for performance exceeds the capabilities of existing materials, new materials with superior properties must be developed. Here we report the realization and characterization of hard cubic Zr3N4 (c-Zr3N4) thin films. The films, deposited using a novel but industrially viable modified filtered cathodic arc (FCA) method, undergo a phase transformation from orthorhombic to cubic above a critical stress level of 9 GPa as determined by X-ray diffraction and Raman spectroscopy. The c-Zr3N4 films are significantly harder (approximately 36 GPa) than both the orthorhombic Zr3N4 (o-Zr3N4) and ZrN films (approximately 27 GPa). The ability to deposit this material directly onto components as a thin film will allow its use in wear- and oxidation-resistant applications.     

Mass transfer studies on ternary systems in a bench-scale liquid-liquid extraction (LLX) column and a comparison with simulations

Mass transfer studies in a laboratory scale extraction column have been conducted for Toluene-Acetone-Water and MIBK-Acetic Acid-Water systems. From these experiments stage-wise solute (Acetone or Acetic-Acid) composition profiles have been obtained for both dispersed and continuous phase. These composition profiles have been compared with those obtained from ASPENPLUS, CHEMSEP and LLXSIM simulators. For liquid-liquid equilibrium calculations all these simulators use UNIFAC and UNIQUAC model. The binary interaction parameters for the UNIFAC are inbuilt in ASPENPLUS and CHEMSEP. UNIQUAC binary parameters were borrowed from DECHEMA. Error square analysis indicates that simulations based onnon-equilibrium option of LLXSIM matchclosely with experimental results. Temperature profiles and hydrodynamic features characterized by number of drops and static holdup on the stages have been compared between the LLXSIM simulated and the experimental results and these match well. However simulations on ASPENPLUS give sum of relative error-squares for all the experimental runs at leastten times higher, in spite of tuning the average stage efficiency.     

The Mukherjee-Islam failure model

This paper provides an extensive discussion on the model given by Mukherjee and Islam [Nav. Res. Log. Quart.30, 487–491 (1983)]. In the first section, a discussion is given on the usefulness of the model as an inventory model, and also the property of forgetfulness is discussed. In the next section, we discuss the range of this distribution, giving some useful suggestions.     

cdc2-like kinase from rat spinal cord specifically phosphorylates KSPXK motifs in neurofilament proteins: isolation and characterization

A protein kinase that phosphorylates a specific KSP sequence [K(S/T)PXK], which is abundant in high molecular weight neurofilament (NF) proteins, was identified and isolated from rat spinal cord. Characterization of this enzyme activity revealed a close relationship with p34cdc2 kinase with respect to its molecular mass (32.5 kDa by SDS/PAGE) and substrate specificities. It could phosphorylate a synthetic peptide analog of the simian virus 40 large tumor antigen, reportedly a specific substrate for p34cdc2 kinase. Histone (H1) and peptide analogs of the KSP sequence present in the C-terminal end of rat and mouse neurofilament proteins were phosphorylated. This kinase did not phosphorylate alpha-casein and peptide substrates of other known second messenger-dependent or -independent kinases. Dephosphorylated rat NF protein NF-H was strongly phosphorylated by the purified enzyme; NF proteins NF-M and native NF-H, but not NF-L, were slightly phosphorylated. Studies on synthetic peptide analogs of KSP repeats with substitution of specific residues, known to be present in the C-terminal regions of NF-H, revealed a consensus sequence of X(S/T)PXK, characteristic of the p34cdc2 kinase substrate. On Western blots, the enzyme was immunoreactive with antibody against the C-terminal end of cdc2 kinase (mouse) and neuronal cdc2-like kinase from rat but not with an antibody against the conserved PSTAIRE region of the p34cdc2 kinase. The antibody against the C-terminal end of cdc2 kinase could immunoprecipitate (immunodeplete) the purified kinase activity. Since the adult nervous system is composed primarily of postmitotic cells, the present observations indicate a nonmitotic role for this cdc2-like kinase activity. The effective phosphorylation of NF-H by this kinase suggests a function in axonal structure.     

Effects of prenatal alcohol exposure on the postnatal morphology of the rat oculomotor nucleus

Morphological development of the rat oculomotor nucleus was investigated on postnatal day 15 following a prenatal ethanol exposure. Analysis of toluidine blue stained plastic sections showed that the prenatal alcohol exposure caused a decrease in the density of neurons and an increase in the density of astrocytes in the center of the nucleus. There was an alcohol-induced reduction in the overall size of the cross-sectional region of the oculomotor nucleus, but no effect on the number of neurons per unit area of that total oculomotor region, indicating a delay or alteration of the migration of neurons to their normal clustered position in the center of the nucleus. The areas of the neuronal cell nucleus and nucleolus were not affected by the alcohol exposure. Analysis of Golgi-Cox-impregnated multipolar neurons showed that the alcohol exposure caused a reduction in area of the cell soma; a reduction in the number of dendritic branches; and a reduction in the complexity of the dendritic arbor relative to distance from the soma, based on concentric ring analysis. The results of this study demonstrate that gestational alcohol exposure can retard the maturation of the oculomotor nucleus.