Grinding-Induced Texture in Ferroelastic Tetragonal Zirconia

Ceria- and yttria-doped tetragonal polycrystalline zirconia ceramics were ground at temperatures as high as 1100°C. X-ray diffraction revealed that the intensity ratio I ₍₀₀₂₎/ I ₍₂₀₀₎ increased (to as high as ∼4.5) compared with that from the as-sintered surfaces (∼0.55). The enhancement in I ₍₀₀₂₎/ I ₍₂₀₀₎ at temperatures well above the m → t transition temperature shows that it is not related to transformation, reversible or otherwise, but can be explained by ferroelastic domain switching.     

UDP-GlcNAc:Ser-protein N-acetylglucosamine-1-phosphotransferase from Dictyostelium discoideum recognizes serine-containing peptides and eukaryotic cysteine proteinases

Phosphoglycosylation catalyzed by UDP-GlcNAc:Ser-protein N-acetylglucosamine-1-phosphotransferase (Ser:GlcNAc phosphotransferase) adds GlcNAcalpha-1-P to peptidyl-Ser of selected Dictyostelium discoideum proteins. Lysosomal cysteine proteinase (CP), proteinase-1(CP7), is the major phosphoglycosylated protein in bacterially grown amoebae. GlcNAc-1-P is added within a Ser-rich domain containing SSS, SGSG, or SGSQ repeated motifs that are not found in other papain-like CPs. We studied the substrate specificity of the transferase using peptides containing these motifs and 12 other peptides with one or more Ser residues. Phosphoglycosylation is comparable for all three Dictyostelium CP motifs, but it is not restricted to them. Flanking residues in the other peptides strongly influence phosphoglycosylation efficiency. Dictyostelium microsomal membranes also phosphoglycosylate endogenous acceptors, and some of these acceptors occur as an 18 S complex with the transferase. CP-serine motif peptides inhibit endogenous acceptor phosphoglycosylation weakly (30-40%) at 800 microM, whereas catalytically inactive proteinase-1(CP7) and other non-phosphoglycosylated eukaryotic CPs, lacking the serine domain, inhibit transferase activity at 1-4 microM. SDS denaturation destroys the inhibitory potential of all CPs showing that transferase recognizes a conformation-dependent feature that is shared by all. Proteinase-1(CP7) expressed in Escherichia coli lacks GlcNAc-1-P, but it is a substrate for Ser:GlcNAc phosphotransferase, Km = 5.6 microM. Thus, Ser:GlcNAc phosphotransferase recognizes both acceptor peptide sequences and a conformational feature of eukaryotic CPs. This may be physiologically important for establishing or maintaining non-overlapping groups of GlcNAc-1-P- and Man-6-P-modified Dictyostelium proteins that reside in functionally distinct endo-lysosomal vesicles.     

Preparation of PAM/PVA blending films by solution-cast technique and its characterization: a spectroscopic study

Polyacrylamide (PAM) and poly(vinyl alcohol) (PVA) were blended with different weight percentages (70/30, 50/50, 30/70) using solution-cast technique. The prepared films were studied by different characterization techniques. The effect of PVA content on PAM blends was investigated by Fourier transform infrared (FTIR), ultra violet visible (UV–vis), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Different mechanical properties of blends were also studied. Significant changes were observed in FTIR, UV–vis, TGA, SEM and mechanical analysis which revealed interactions between the two polymers. FTIR spectra showed the presence of hydrogen bonding between PAM and PVA and hydrophilic nature of the blends. Different optical properties were studied by UV–vis spectroscopy. The weight loss, as a function of temperature of blends, was analyzed by TGA. The results obtained from different experimental techniques were supported by SEM image analysis. FTIR analysis confirmed the conclusion on the specific hydrogen bonding between –CONH₂ groups in PAM and –OH group in PVA. These results showed the change in the thermal stability and mechanical properties. FTIR analysis revealed that a blend ratio of 50/50 wt% had maximum intermolecular interaction between two polymers. It was finally concluded that blend films with the above ratio display higher thermal stability and improved mechanical properties. Due to changes in interactions, the optical parameters were also changed.     

Ag and O ion irradiation induced improvement in dielectric properties of the Ba(Co1/3Nb2/3)O3 thin films

We present the preliminary results of temperature and frequency dependent dielectric measurements on Ba(Co_1/3Nb_2/3)O₃ (BCN) thin films. These films were prepared on indium tin oxide (ITO) coated glass substrates by the pulse laser deposition (PLD) technique. It exhibits single-phase hexagonal symmetry. These films were irradiated with Ag¹⁵⁺ (200 MeV) and O⁷⁺ (100 MeV) beams at the fluence 1 × 10¹¹, 1 × 10¹², and 1 × 10¹³ ions/cm². On irradiating these films, its dielectric constant (?′) and dielectric loss (tan δ) parameters improve compared to un-irradiated film. Compared to O⁷⁺ irradiation induced point/cluster defects Ag¹⁵⁺ induced columnar defects are more effective in reducing/pinning trapped charges within grains. The present paper highlights the role of swift heavy ion irradiation in engineering the dielectric properties of conductive samples to enable them to be useful for microwave device applications.     

High-resolution full-field optical coherence microscopy using a Mirau interferometer for the quantitative imaging of biological cells

In this paper quantitative imaging of biological cells using high-resolution full-field optical coherence microscopy (FF-OCM) is reported. The FF-OCM was realized using a swept-source system, a Mirau interferometer, and a CCD camera (a two-dimensional detection unit). A Mirau-interferometric objective lens was used to generate the interferometric signal. The signal was analyzed by a Fourier analysis technique. Optically sectioned amplitude images and a quantitative phase map of biological cells such as onion skin and red blood cells (RBCs) are demonstrated. Further, the refractive index profile of the RBCs is also presented. For the 50× Mirau objective, the experimentally achieved axial and transverse resolution of the present system are 3.8 and 1.2 μm, respectively. The CCD provides parallel detection and measures enface images without X, Y, Z mechanical scanning.     

Adsorption isotherms for red chilli (Capsicum annum L.)

The adsorption equilibrium moisture contents for red chilli were determined experimentally in relative humidity range of 11–97% at the temperatures of 20, 30, 40, and 50°C. Six equilibrium moisture content models were fitted to the experimental data. The modified Oswin model was the best fitted equation for relative humidity range of 11–97% for the adsorption data of red chilli.     

Change in colony morphology influences the virulence as well as the biochemical properties of the Mycobacterium avium complex

Factors that influence colony morphology are of crucial importance for drug development as well as for understanding the virulence of Mycobacterium avium complex (MAC) strains. The MAC 101 strain used in the present study grows as smooth transparent (SmT) colonies that tend to become opaque and pigmented when incubated for long periods of time. However, when MAC was passaged in animals, two types of colonies were recovered. The new rough transparent (RgT) colony morphology appeared more flat and transparent, having a central spot, irregular edges at times, and a dry, granular appearance like that of the rough mutants. In animal studies, the RgT bacilli multiplied at a much faster rate than that of the SmT bacilli, causing 60-80% mortality compared with the 10% mortality observed in mice infected with SmT. In vitro studies indicated that the SmT MAC did not grow and multiply as well in resident peritoneal macrophages as the RgT MAC did. The two morphotypes did not differ in their growth ratesin vitro but the RgT MAC failed to reduce dimethylthiazol-diphenyltetrazolium bromide (MTT), alamar blue and neutral red, suggesting that there might be significant changes in the cell wall or elsewhere causing changes in cellular permeability. These two morphotypes could serve as models for studying the biochemical markers or the identification of factors responsible for the virulence of the MAC.     

Use of evidence in the process of practice change in a clinical team: a study-forming part of the Autocontrol Project

The Autocontrol Project is concerned with the accessing, processing and communication of high quality information so that a clinical team can make and implement decisions for practice change, and then evaluate if improvement has been achieved. High quality information is used as evidence for change. In this study, we have evaluated how evidence is used by a clinical team to explain an identified problem of inappropriate use of blood gas tests. In an experimental study of the Surgical Intensive Care Unit, video recordings of team meetings of nurses and doctors were undertaken, structured according to a problem-based format. Evidence of current practice patterns derived from the hospital information system, as well as the results of a questionnaire to the unit's staff about knowledge and use of blood gas measurements, were supplied to the participants beforehand. At the second meeting, the output of the first meetings and a summarised analysis of pertinent literature were made available. This second meeting was required to finalise the list of causes of inappropriate blood gas use and propose pragmatic strategies for practice change. The video data of the meetings were coded to analyse the use of evidence, the categories of causes, issues and solutions proposed, and the quality of team interaction. The results indicate that in order to achieve consensus, the team used different types of evidence, including objective evidence of practice patterns, personal experience about direct and indirect organisational influences, and literature-based research evidence of best practice. Furthermore, group dynamics were favoured by the problem-based meeting structure, and a high level of cognitive critiquing between team members was observed. This research suggests that a combination of approaches involving identification of both operational factors (e.g. appropriate access to different types of evidence and meeting structure) and cognitive and behavioural approaches (e.g. ensuring expression of different viewpoints) is needed to support strategic decision-making for practice change in a clinical unit. This combined approach should favourably influence the provision of an effective and efficient evidence support environment for the clinical team.