153 research outputs found
Streptococcus sanguis adhesins mediating attachment to saliva-coated hydroxyapatite beads
No full textStreptococcus sanguis 12 adhesins mediating attachment to saliva-coated hydroxyapatite beads (S-HA) were isolated and characterized. Cell surface fibrils were released from this organism by a method of freeze-thawing followed by brief homogenization. Fibrils in the homogenate were precipitated by ultracentrifugation or ammonium sulphate precipitation. This precipitate was shown to contain fibrils by electron microscopy. Sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis (PAGE) analysis of fibrils showed a single band which stained with Coomassie blue and periodate-Schiff. The molecule had a Mr in excess of 300,000. This protein has been given the name long-fibril protein (LFP). Antibody raised against the LFP reacted with long fibrils of S. sanguis 12. LFP was degraded by subtilisin, pronase, papain, and trypsin, but not by chymotrypsin and muramidases. Fibrils were hydrolyzed by subtilisin into discrete lower Mr protein bands which reacted with both anti-fibril and anti-LFP serum. F(ab')₂ prepared from anti-fibril IgG inhibited adhesion of S. sanguis 12 to pH modified S-HA, indicating that fibrils were acting as an adhesin mediating attachment via the neuraminidase-sensitive receptor on S-HA.
Five recombinant clones expressing surface antigens of S. sanguis 12 were isolated by ligating a partial digest of S. sanguis 12 chromosomal DNA with the plasmid vector pUC 18, and transforming into Escherichia coli JM83. Recombinant clones were screened by a colony immunoassay with antisera raised against either S. sanguis 12 whole cells or with anti-fibril serum. Positive clones were then analyzed by SDS-PAGE, Western blotting and restriction endonuclease digestion of recombinant plasmids. One recombinant plasmid, pSA2 expressed two proteins of Mrs of 20,000 and 36,000. The 36,000-Mr protein has been designated as SsaB (S. sanguis adhesin B). Both proteins were purified to homogeneity by gel filtration and ion exchange chromatography. Anti-SsaB serum was used in an immunogold bead labelling experiment to demonstrate that this protein was present on the surfaces of S. sanguis 12 and in the non-saliva-aggregating variant 12na, but not on the non-adhering non-aggregating hydrophilic variant 12L. Western blot analysis with anti-SsaB and anti-20 kd sera showed that both SsaB and the 20 kd proteins were present in cell extracts of S. sanguis 12 and its variants. SsaB inhibited adhesion of S. sanguis 12na to S-HA, indicating that it was the adhesin which mediates the binding to the pH-sensitive receptor. SsaB was found to be present on all S. sanguis strains tested, but not on other oral streptococci. Chemical cross-linking studies of SsaB on S. sanguis 12 cell surface suggested that this protein may be present in a higher Mr complex.
This study provides direct evidence that binding of S. sanguis 12 to S-HA involves at least two adhesin-receptor interactions. The adhesin mediating binding to the neuraminidase-sensitive receptor on S-HA involves the long fibrils and the adhesin binding to the acid labile receptor is a 36,000 Mr protein.Science, Faculty ofMicrobiology and Immunology, Department ofGraduat
Systematic reviews and meta-analysis: Understanding the best evidence in primary healthcare
No full textHealthcare decisions for individual patients and for public health policies should be informed by the best available research evidence. The practice of evidence-based medicine is the integration of individual clinical expertise with the best available external clinical evidence from systematic research and patient′s values and expectations. Primary care physicians need evidence for both clinical practice and for public health decision making. The evidence comes from good reviews which is a state-of-the-art synthesis of current evidence on a given research question. Given the explosion of medical literature, and the fact that time is always scarce, review articles play a vital role in decision making in evidence-based medical practice. Given that most clinicians and public health professionals do not have the time to track down all the original articles, critically read them, and obtain the evidence they need for their questions, systematic reviews and clinical practice guidelines may be their best source of evidence. Systematic reviews aim to identify, evaluate, and summarize the findings of all relevant individual studies over a health-related issue, thereby making the available evidence more accessible to decision makers. The objective of this article is to introduce the primary care physicians about the concept of systematic reviews and meta-analysis, outlining why they are important, describing their methods and terminologies used, and thereby helping them with the skills to recognize and understand a reliable review which will be helpful for their day-to-day clinical practice and research activities
Exploring the Potential of Integrating Machine Tool Wear Monitoring and ML for Predictive Maintenance - A Review
No full textThis research review article explores the potential of integrating machine tool wear monitoring and ML algorithms for predictive maintenance. It synthesizes the latest research in the field, while discussing the benefits and challenges of various approaches. Specifically, this review examines the applications of sensors in machine tool condition monitoring, the use of ML algorithms to detect wear patterns and predict maintenance needs, and the potential of integrating ML and predictive maintenance. The article also evaluates the potential of using ML algorithms in conjunction with sensor data to improve tool performance and reduce maintenance costs. Finally, the article provides scope for future research to expand the potential of ML for predictive maintenance in machine tools. Overall, this review highlights the potential of integrating ML with predictive maintenance for machine tool applications
Digital Twin Technology for Tool Condition Monitoring: A Review of Recent Research
No full textThis research review article examines the use of Digital Twin technology (DT) in Tool Condition Monitoring (TCM). DT is a powerful technology that enables the creation of an exact digital replica of real-world entities, such as machines and tools, providing an integrated representation of various physical and virtual components. By combining real-time data with digital models of the tools, DT can be used to monitor tool condition and detect potential issues before they become serious. This review article surveys recent research on the use of DT in TCM and discusses the challenges that need to be addressed in order to make DT a viable solution for industrial tool monitoring. It also provides insight into future directions for research in this field. The results of this review suggest that DT has great potential to revolutionize tool monitoring in the manufacturing industry
Cell surface of hydrophobic and hydrophilic strains of Streptococcus sanguis
No full textCell surfaces of aggregation, adherence or hydrophilic variants of Streptococcus sanguis were compared to cell surfaces of the parent strain with regard to their protein and antigenic constituents. Cell surface molecules were released by digestion with mutanolysin. Extraction with SDS-BME, urea, lithium chloride and boiling water did not solubilize any material which stained with silver nitrate in an SDS-polyacrylamide gel. The parent organism S. sanguis 12 which aggregates in saliva, adheres to saliva coated hydroxyapatite (S-HA) and is hydrophobic was found to possess a prominently staining 160,000 MW protein. This protein was almost completely absent from strain I2na, a hydrophobic non-aggregating variant, and was completely absent from the hydrophilic non-aggregating, non-adherent strain 12L. Trypsinization of strain 12 resulted in the coincident loss of the 160,000 MW protein and the ability to aggregate in saliva. Trypsin treatment reduced, but did not eliminate the hydrophobic character of the cells. Boiling destroyed the ability to aggregate but did not alter hydrophobicity. Cell wall digests of strain 12 contained a large number of proteins which were absent from strains 12na and 12L. Mutanolysin digests of the hydrophilic strains contained no material that was visible in a silver stained SDS-polyacrylamide gel. Electron microscopy of phosphotungstic acid stained cells showed a thick capsular material spread evenly over the cell surface of the parent strain 12. This layer was thinner around the cells of strain 12na and appeared patchy on hydrophilic strains. Electron microscopy of uranyl acetate stained cells revealed that strain 12 had short fibrillar structures evenly distributed over the cell surface, and long fibrils which were more concentrated at the end of the cell. The hydrophilic strain 12L lacked both types of fibrils. Crossed immunoelectrophoresis confirmed that the major cell surface antigens were located in the 160,000 MW region. Cell wall digests of strain 12 and 12na inhibited adherence of strain 12 to S-HA by 36% and 19% respectively. The digests of hydrophilic strain 12L were not inhibitory. The inhibitory activity was sensitive to heat and SDS.Science, Faculty ofMicrobiology and Immunology, Department ofGraduat
Comparative study of Proportional Integral and Backstepping controller for Buck converter
No full textSecure and efficient transmission in wireless network using key authentication based secured multicasting technique
No full textAn Approach to Implement Cryptographic Protocol Version Downgrade Within a Secure Internal Network: TLS 1.x to SSL
No full textThe end to end encryption of connections over the internet have evolved from SSL to TLS 1.3 over the years. Attacks have exposed vulnerabilities on each upgraded version of the cryptographic protocols used to secure connections over the internet. Organisations have to keep updating their web based applications to use the latest cryptographic protocol to ensure users are protected and feel comfortable using their web applications. But, the problem is that, web applications are not always standalone systems, there is usually a maze of systems that are integrated to provide services to the end user. The interactions between these systems happens within the controlled internal private network environment of the organisation. While only the front ending web application is visible to the end user. It is not often feasible to upgrade all internal systems to use the latest cryptographic protocol for internal interfaces/integration due to prohibitive cost of redevelopment and upgrades to infra and systems. Here we define an algorithm to setup internal & external firewalls to downgrade to a lower version of the cryptographic protocol (SSL) within the internal network for the integration/interfacing connections of internal systems while mandating the latest cryptographic protocol (TLS 1.x) for end user connections to the web application
Author Commitment and Social Power: Automatic Belief Tagging to Infer the Social Context of Interactions
No full text- …
