Nondestructive Evaluation in Quality Assurance

An attempt is made to discuss in brief the current philosophy and trends in quality assurance through nondestructive testing. The techniques currently in use and those being developed for newer and advanced materials such as composites are reviewed. 27 ref.--AA

Local variability and base sequence effects in DNA crystal structures.

The importance and usefulness of local doublet parameters in understanding sequence dependent effects has been described for A- and B-DNA oligonucleotide crystal structures. Each of the two sets of local parameters described by us in the NUPARM algorithm, namely the local doublet parameters, calculated with reference to the mean z-axis, and the local helical parameters, calculated with reference to the local helix axis, is sufficient to describe the oligonucleotide structures, with the local helical parameters giving a slightly magnified picture of the variations in the structures. The values of local doublet parameters calculated by NUPARM algorithm are similar to those calculated by NEWHELIX90 program, only if the oligonucleotide fragment is not too distorted. The mean values obtained using all the available data for B-DNA crystals are not significantly different from those obtained when a limited data set is used, consisting only of structures with a data resolution of better than 2.4 A and without any bound drug molecule. Thus the variation observed in the oligonucleotide crystals appears to be independent of the quality of their crystallinity. No strong correlation is seen between any pair of local doublet parameters but the local helical parameters are interrelated by geometric relationships. An interesting feature that emerges from this analysis is that the local rise along the z-axis is highly correlated with the difference in the buckle values of the two basepairs in the doublet, as suggested earlier for the dodecamer structures (Bansal and Bhattacharyya, in Structure & Methods: DNA & RNA, Vol. 3 (Eds., R.H. Sarma and M.H. Sarma), pp. 139-153 (1990)). In fact the local rise values become almost constant for both A- and B-forms, if a correction is applied for the buckling of the basepairs. In B-DNA the AA, AT, TA and GA basepair sequences generally have a smaller local rise (3.25 A) compared to the other sequences (3.4 A) and this seems to be an intrinsic feature of basepair stacking interaction and not related to any other local doublet parameter. The roll angles in B-DNA oligonucleotides have small values (less than +/- 8 degrees), while mean local twist varies from 24 degrees to 45 degrees. The CA/TG doublet sequences show two types of preferred geometries, one with positive roll, small positive slide and reduced twist and another with negative roll, large positive slide and increased twist.(ABSTRACT TRUNCATED AT 400 WORDS)

Common epitopes of serum retinol-binding proteins: a study with monoclonal antibodies

Monoclonal antibodies were raised against purified chicken retinol-binding protein. These were characterised extensively with respect to their ability to recognize retinol-binding proteins from different species. The monoclonal antibodies exhibited differential recognition characteristics. Though the majority presented restricted reactivities, one out of the four monoclonal antibodies studied cross-reacted with retinol-binding proteins from all species tested so far.

Characterization of poly- and monoclonal antibodies to physalis mottle (tymo) virus

Polyclonal antibodies were raised against the Physalis mottle virus (PhMV) and its denatured coat protein (PhMV-P). Analysis of the reactivity of the polyclonal antibodies with tryptic peptides of PhMV-P in dot-blot assays revealed that many of the epitopes were common to intact virus and denatured coat protein. Five monoclonal antibodies to the intact virus were obtained using hybridoma technology. These monoclonal antibodies reacted well with the denatured coat protein. Epitope analysis suggested that probably these monoclonal antibodies recognize overlapping epitopes. This was substantiated by epitope mapping using the CNBr digest of PhMV-P in western blots. All the five monoclonals recognized the N-terminal 15 K fragment. Attempts to further delineate the specific region recognized by the monoclonals by various enzymatic cleavages resulted in the loss of reactivity in all the cases. The results indicate that these monoclonals probably recognize epitopes within the N-terminal 15 K fragment of the coat protein.

Identification of collagenolytic MMP networks as potential biomarkers in progressive chronic periodontitis subjects and MMP-8 null allele model

Chronic periodontitis results from a complex aetiology, including the formation of a subgingival biofilm and the elicitation of the host s immune and inflammatory response. The hallmark of chronic periodontitis is alveolar bone loss and soft periodontal tissue destruction. Evidence supports that periodontitis progresses in dynamic states of exacerbation and remission or quiescence. The major clinical approach to identify disease progression is the tolerance method, based on sequential probing. Collagen degradation is one of the key events in periodontal destructive lesions. Matrix metalloproteinase (MMP)-8 and MMP-13 are the primary collagenolytic MMPs that are associated with the severity of periodontal inflammation and disease, either by a direct breakdown of the collagenised matrix or by the processing of non-matrix bioactive substrates. Despite the numerous host mediators that have been proposed as potential biomarkers for chronic periodontitis, they reflect inflammation rather than the loss of periodontal attachment. The aim of the present study was to determine the key molecular MMP-8 and -13 interactions in gingival crevicular fluid (GCF) and gingival tissue from progressive periodontitis lesions and MMP-8 null allele mouse model. In study (I), GCF and gingival biopsies from active and inactive sites of chronic periodontitis patients, which were determined clinically by the tolerance method, and healthy GCF were analysed for MMP-13 and tissue inhibitor of matrix metalloproteinases (TIMP)-1. Chronic periodontitis was characterised by increased MMP-13 levels and the active sites showed a tendency of decreased TIMP-1 levels associated with increments of MMP-13 and total protein concentration compared to inactive sites. In study (II), we investigated whether MMP-13 activity was associated with TIMP-1, bone collagen breakdown through ICTP levels, as well as the activation rate of MMP-9 in destructive lesions. The active sites demonstrated increased GCF ICTP levels as well as lowered TIMP-1 detection along with elevated MMP-13 activity. MMP-9 activation rate was enhanced by MMP-13 in diseased gingival tissue. In study (III), we analysed the potential association between the levels, molecular forms, isoenzyme distribution and degree of activation of MMP-8, MMP-14, MPO and the inhibitor TIMP-1 in GCF from periodontitis progressive patients at baseline and after periodontal therapy. A positive correlation was found for MPO/MMP-8 and their levels associated with progression episodes and treatment response. Because MMP-8 is activated by hypochlorous acid in vitro, our results suggested an interaction between the MPO oxidative pathway and MMP-8 activation in GCF. Finally, in study (IV), on the basis of the previous finding that MMP-8-deficient mice showed impaired neutrophil responses and severe alveolar bone loss, we aimed to characterise the detection patterns of LIX/CXCL5, SDF-1/CXCL12 and RANKL in P. gingivalis-induced experimental periodontitis and in the MMP-8-/- murine model. The detection of neutrophil-chemoattractant LIX/CXCL5 was restricted to the oral-periodontal interface and its levels were reduced in infected MMP-8 null mice vs. wild type mice, whereas the detection of SDF-1/CXCL12 and RANKL in periodontal tissues increased in experimentally-induced periodontitis, irrespectively from the genotype. Accordingly, MMP-8 might regulate LIX/CXCL5 levels by undetermined mechanisms, and SDF-1/CXCL12 and RANKL might promote the development and/or progression of periodontitis.

Numerical and experimental study of the thermal behaviour of coining and upsetting processes

A numerical simulation technique has been employed to study the thermal behavior of hot-forging type forming processes. Experiments on the coining and upsetting of an aluminum billet were conducted to validate the numerical predictions. Typical forming conditions for both the coining and upsetting processes were then studied in detail. an electrical analogy scheme was used to determine the thermal contact resistance. This scheme can conviniently provide the interface characteristics for typical processing conditions, which normally involve high pressures and temperatures. A single forging cycle was first considered, and then a batch of twenty-five forgings was studied. Each forging cycle includes the billet mounting, ascent, loading, dwelling, unloading, descent, and billet removal stages. The temperature distribution in the first forging to be formed is found to be significantly different from that at the end of the batch. In industry, forging is essentially a batch operation. The influence of forming speed and reduction on thermal characteristics was investigated also. The variations that can occur in the process design by considering differences in temperature characteristics are discussed also.

Correlations, quantum entanglement and interference in nanoscopic systems

Several of the most interesting quantum effects can or could be observed in nanoscopic systems. For example, the effect of strong correlations between electrons and of quantum interference can be measured in transport experiments through quantum dots, wires, individual molecules and rings formed by large molecules or arrays of quantum dots. In addition, quantum coherence and entanglement can be clearly observed in quantum corrals. In this paper we present calculations of transport properties through Aharonov-Bohm strongly correlated rings where the characteristic phenomenon of charge-spin separation is clearly observed. Additionally quantum interference effects show up in transport through pi-conjugated annulene molecules producing important effects on the conductance for different source-drain configurations, leading to the possibility of an interesting switching effect. Finally, elliptic quantum corrals offer an ideal system to study quantum entanglement due to their focalizing properties. Because of an enhanced interaction between impurities localized at the foci, these systems also show interesting quantum dynamical behaviour and offer a challenging scenario for quantum information experiments.

Cloning and sequence of a cDNA encoding a novel hybrid prolme-rich protein associated with cytokinin-induced haustoria formation in Cuscuta reflexa

A complete cDNA encoding a novel hybrid Pro-rich protein (HyPRP) was identified by differentially screening 3x10(4) recombinant plaques of a Cuscuta reflexa cytokinin-induced haustorial cDNA library constructed in lambda gt10. The nucleotide (nt) sequence consists of: (i) a 424-bp 5'-non coding region having five start codons (ATGs) and three upstream open reading frames (uORFs); (ii) an ORF of 987 bp with coding potential for a 329-amino-acid (aa) protein of M(r), 35203 with a hydrophobic N-terminal region including a stretch of nine consecutive Phe followed by a Pro-rich sequence and a Cys-rich hydrophobic C terminus; and (iii) a 178-bp 3'-UTR (untranslated region). Comparison of the predicted aa sequence with the NBRF and SWISSPROT databases and with a recent report of an embryo-specific protein of maize [Jose-Estanyol et al., Plant Cell 4 (1992) 413-423] showed it to be similar to the class of HyPRPs encoded by genes preferentially expressed in young tomato fruits, maize embryos and in vitro-cultured carrot embryos. Northern analysis revealed an approx. 1.8-kb mRNA of this gene expressed in the subapical region of the C. reflexa vine which exhibited maximum sensitivity to cytokinin in haustorial induction.

Diacylglycerol Kinase Is Stimulated by Arachidonic Acid in Neural Membranes.

The effect of arachidonic acid (AA) on the activity of diacylglycerol (DG) kinase in neural membranes was investigated. When rat brain cortical membranes were incubated with 0.5 mM dipalmitin and [gamma-P-32]ATP, formation of phosphatidic acid (PA) was observed. It was linear up to 5 min, and the initial rate was similar to 1.0 nmol/min/mg of protein. The DG kinase activity was stimulated twofold by 0.25 mM AA. The stimulation was apparent at the earliest time point measured (1 min) and with the lowest concentration of AA tested (62.5 mu M). The stimulation was proportional to the concentration of AA up to 250 mu M. AA was the most potent stimulator of DG kinase, and linolenic acid showed similar to 40% stimulation. Oleic acid showed no effect, whereas linoleic and the saturated fatty acids tested were inhibitory. AA stimulation of DG kinase was observed only with membranes of cerebrum, cerebellum, and myelin and not with brain cytosol or liver membranes. AA also stimulated the formation of PA in the absence of added dipalmitin (endogenous activity) with membranes prepared from whole brain. DG kinase of neural membranes was extracted with 2 M NaCl, which on dialysis yielded a precipitate. Both the precipitate and the supernatant showed DG kinase activity, but only the enzyme in the precipitate was stimulated by AA at concentrations as low as 25 mu M. It is suggested that AA, through its effect on DG kinase, regulates the level of DG in neural membranes, which in turn regulates protein kinase C activity.

Inhibition of nuclear protein import by a monoclonal antibody against a novel class of nuclear pore proteins

Nuclear import of proteins is mediated by the nuclear pore complexes in the nuclear envelope and requires the presence of a nuclear localization signal (NLS) on the karyophilic protein. In this paper, we describe studies with a monoclonal antibody, Mab E2, which recognizes a class of nuclear pore proteins of 60-76 kDa with a common phosphorylated epitope on rat nuclear envelopes. The Mab Ea-reactive proteins fractionated with the relatively insoluble pore complex-containing component of the envelope and gave a finely punctate pattern of nuclear staining in immunofluorescence assays. The antibody did not bind to any cytosolic proteins. Mab E2 inhibited the interaction of a simian virus 40 large T antigen NLS peptide with a specific 60-kDa NLS-binding protein from rat nuclear envelopes in photoaffinity labeling experiments. The antibody blocked the nuclear import of NLS-albumin conjugates in an in vitro nuclear transport assay with digitonin-permeabilized cells, but did not affect passive diffusion of a small nonnuclear protein, lysozyme, across the pore. Mab E2 may inhibit protein transport by directly interacting with the 60-kDa NLS-binding protein, thereby blocking signal-mediated nuclear import across the nuclear pore complex. (C) 1994 Academic Press, Inc.

Squeezed vacuum as an eigenstate of two-photon annihilation operator

We introduce the inverse annihilation and creation operators a-1 and a(dagger-1) by their actions on the number states. We show that the squeezed vacuum exp(1/2xia(dagger2)]\0] and squeezed first number state exp[1.2xia(dagger2)]\n = 1] are respectively the eigenstates of the operators (a(dagger-1)a) and (aa(dagger-1)) with the eigenvalue xi.

Isolation and characterization of riboflavin carrier protein from human amniotic fluid

A specific protein exhibiting immunological cross-reactivity with chicken riboflavin carrier protein has been purified to homogeneity from human amniotic fluid by use of ion-exchange and affinity chromatography. The protein is similar to its avian counterpart in terms of molecular size, distribution of 125I-labelled tryptic peptides during finger printing, and preferential binding to riboflavin. Immunologically, they are homologous since most of the monoclonal antibodies raised against the avian protein cross-react with the purified human vitamin carrier.

Establishment of the functional importance of thiamin carrier protein in pregnant rats by using monoclonal antibodies

Monoclonal antibodies (mAbs) to chicken thiamin carrier protein (TCP) have been produced by hybridoma technology to identify the crucial epitopes involved in bioneutralization of the vitamin carrier. The monoclonality of these mAbs (A4C4, F3H6, H8H3, C8C1 and G7H10) was sought to be confirmed by sub-class isotyping; they all belong to IgG1, k type. The epitopes recognized by all the five mAbs are conserved in TCP from the chicken to the rat as assessed by liquid phase RIA and immunoprecipitation of I-125-labelled proteins from pregnant rat serum. Among these mAbs, passive immunization of pregnant rats with the mAb C8C1 only on three consecutive days (day 10, 11 and 12) resulted in embryonic resorption. These results demonstrate the importance of epitopic structure specified by the mAb C8C1 on TCP during pregnancy in rats.

Comparative Nucleotide and Amino Acid Sequence Analysis of the Sequence-Specific RNA-Binding Rotavirus Nonstructural Protein NSP3

NSP3, an acidic nonstructural protein, encoded by gene 7 has been implicated as the key player in the assembly of the 11 viral plus-strand RNAs into the early replication intermediates during rotavirus morphogenesis. To date, the sequence or NSP3 from only three animal rotaviruses (SA11, SA114F, and bovine UK) has been determined and that from a human strain has not been reported. To determine the genetic diversity among gene 7 alleles from group A rotaviruses, the nucleotide sequence of the NSP3 gene from 13 strains belonging to nine different G serotypes, from both humans and animals, has been determined. Based on the amino acid sequence identity as well as phylogenetic analysis, NSP3 from group A rotaviruses falls into three evolutionarily related groups, i.e., the SA11 group, the Wa group, and the S2 group. The SA 11/SA114F gene appears to have a distant ancestral origin from that of the others and codes for a polypeptide of 315 amino acids (aa) in length. NSP3 from all other group A rotaviruses is only 313 aa in length because of a 2-amino-acid deletion near the carboxy-terminus, While the SA114F gene has the longest 3' untranslated region (UTR) of 132 nucleotides, that from other strains suffered deletions of varying lengths at two positions downstream of the translational termination codon. In spite of the divergence of the nucleotide (nt) sequence in the protein coding region, a stretch of about 80 nt in the 3' UTR is highly conserved in the NSP3 gene from all the strains. This conserved sequence in the 3' UTR might play an important role in the regulation of expression of the NSP3 gene. (C) 1995 Academic Press, Inc.

DNA Condensation by the Rat Spermatidal Protein TP2 Shows GC-Rich Sequence Preference and Is Zinc Dependent

Transition protein-2 (TP2), isolated from rat testes, was recently shown to be a zinc metalloprotein. We have now carried out a detailed analysis of the DNA condensing properties of TP2 with various polynucleotides using circular dichroism spectroscopy. The condensation of the alternating copolymers by TP2 (incubated with 10 mu M ZnSO4), namely, poly(dG-dC). poly(dG-dC) and poly(dA-dT). poly(dA-dT), was severalfold higher than condensation of either of the homoduplexes poly(dG). poly-(dC) and poly(dA). poly(dT) or rat oligonucleosomal DNA. Between the two alternating copolymers, poly(dG-dC). poly(dG-dC) was condensed 3.2-fold more effectively than poly(dA-dT). poly(dA-dT). Preincubation of TP2 with 5 mM EDTA significantly reduced its DNA-condensing property. Interestingly, condensation of the alternating copolymer poly(dI-dC). poly(dI-dC) by TP2 was much less as compared to that of poly(dG-dC). poly(dG-dC). The V8 protease-derived N-terminal fragment (88 aa) condensed poly(dA-dT). poly(dA-dT) to a very small extent but did not have any effect on poly(dG-dC). poly-(dG-dC). The C-terminal fragment (28 aa) was able to condense poly(dA-dT) . poly(dA-dT) more effectively than poly(dG-dC). poly(dG-dC). These results suggest that TP2 in its zinc-coordinated form condenses GC-rich polynucleotides much more effectively than other types of polynucleotides. Neither the N-terminal two-thirds of TP2 which is the zinc-binding domain nor the C-terminal basic domain are as effective as intact TP2 in bringing about condensation of DNA.