No abstract

No abstract

Hydrosol of Au nanoparticles was prepared by citrate reduction of chloroauric acid. The synthesized nanoparticles were characterized through transmission electron microscopy (TEM) and UV–Visible spectroscopy. The prepared nanoparticles were almost spherical in shape with their mean diameter ∼6 nm and possessed face-centred-cubic (fcc) structure. The absorption spectrum of the as-prepared nanoparticles shows the SPR peak at 530 nm in agreement with that predicted from calculations based on Mie theory. These nanoparticles were dispersed in poly(vinyl alcohol) (PVA) using the sol–gel method to prepare PVA–Au nanocomposite films with different concentrations of Au. Optical and structural properties of these nanocomposites were studied using UV–Visible spectroscopy, x-ray diffraction (XRD) and FTIR spectroscopy. The value of optical band gap deduced from the UV–Visible absorption spectroscopy is found to be reduced from 4.98 eV (for pure PVA) to 3.85 eV after embedding 0.074 wt% of Au nanoparticles. Further, the refractive index behaviour for pure PVA and PVA–Au nanocomposite films was studied through transmission and reflection behaviour. The induced structural changes, revealed through XRD and FTIR spectroscopy, are responsible for the observed changes in optical behaviour of PVA after embedding Au nanoparticles in it.

No abstract

Seminal plasma aids sperm by inhibiting premature capacitation, helping in the intracervical transport and formation of an oviductal sperm reservoir, all of which appear to be important in the fertilization process. Epitopes such as Lewis x and y are known to be present on seminal plasma glycoproteins, which can modulate the maternal immune response. It is suggested by multiple studies that seminal plasma glycoproteins play, largely undiscovered, important roles in the process of fertilization. We have devised a strategy to analyze glycopeptides from a complex, unknown mixture of protease-digested proteins. This analysis provides identification of the glycoproteins, glycosylation sites, glycan compositions, and proposed structures from the original sample. This strategy has been applied to human seminal plasma total glycoproteins. We have elucidated glycan compositions and proposed structures for 243 glycopeptides belonging to 73 N-glycosylation sites on 50 glycoproteins. The majority of the proposed glycan structures were complex type (83%) followed by high-mannose (10%) and then hybrid (7%). Most of the glycoproteins were either sialylated, fucosylated, or both. Many Lewis x/a and y/b epitopes bearing glycans were found, suggesting immune-modulating epitopes on multiple seminal plasma glycoproteins. The study also shows that large scale N-glycosylation mapping is achievable with current techniques and the depth of the analysis is roughly proportional to the prefractionation and complexity of the sample.