Strain analysis at flat surfaces of loaded members using digital image correlation technique

This research examines the applicability of the planned Digital Image Correlation (DIC) system to measure the strains in tensile experiments. DIC is a low-cost optical technique, and is an appropriate measurement used to measure surface displacement, strain and stress map distribution without any contact with the tested surfaces. In the present research, the tensile test is conducted on two different flat samples, which are painted in a speckle pattern on the tested surface to use DIC features in stain measurements. To guarantee the efficiency of the planned DIC system, the DIC code has been built using MATLAB programming language.  The obtained results from DIC technique is compared with the results from open-source software (Ncorr), the finite element analysis (ANSYS) as well as the exact and analytical solutions. The comparison results showed that there was A quite acceptable and agreement achieved between them. According to the exact solution, the percentage of accuracy of the obtained results for the Aluminum without hole plate was around (89-93) % whereas the accuracy with the NCORR was about 96 %. For the second copper plate with a central hole, the accuracy has been obtained to be (80.7-99) % with the analytical solution wherein its value has reached (81-97) % with Ncorr software

Case report: Unusual cause of difficulty in intubation and ventilation with asthmatic-like presentation of Endobronchial Tuberculosis

Endobronchial Tuberculosis is hazardous in causing circumferential narrowing of tracheobronchial tree despite the eradication of tubercle bacilli in the initial insult from Pulmonary Tuberculosis. They may present as treatment resistant bronchial asthma and pose challenge to airway management in the acute setting. We present a 25 year-old lady who was newly diagnosed bronchial asthma with a past history of Pulmonary Tuberculosis that had completed treatment. She presented with sudden onset of difficulty breathing associated with noisy breathing for 3 days and hoarseness of voice for 6 months. Due to resistant bronchospasm, attempts were made to secure the airway which led to unanticipated difficult intubation and ventilation. Subsequent investigations confirmed the diagnosis of Endobronchial Tuberculosis and patient was managed successfully with anti TB medication, corticosteroids and multiple sessions of tracheal dilatation for tracheal stenosis. This case highlights the unusual cause of difficulty in intubation and ventilation due to Endobronchial Tuberculosis, which required medical and surgical intervention to improve the condition

Noise risk assessment on noise exposure among urban rail maintenance worker using personal monitoring method

Urban Rail maintenance work usually involves a lot of daily mainte-nance work as proper maintenance must always be a priority for the rail industry to ensure the passengers are always comfortable and safe. These maintenance activities expose the technician to noise as they handle a lot of hand tools and machinery while performing their tasks. Noise Induced Hearing Loss (NIHL) is a major compensable occupational disease in Malaysia due to excessive noise-exposed above the permissible daily noise exposure limit. This study aimed to conduct Personal Monitoring as a part of Noise Risk Assessment (NRA) to meas-ure the level of noise exposure received among maintenance technicians in the excessive noise area. This study focuses on the areas and tasks involved in the Track Network Maintenance Hall (TNMH) and Track Vehicle Storage Building (TVSB) at one of the urban rail companies. Noise Risk Assessment was the se-lected method to measure the level of noise exposure among maintenance tech-nicians in the excessive noise area. The Personal Monitoring method was con-ducted as suggested in the ICOP provided by DOSH Malaysia. Data recorded shows that a total of 2 out of 3 technicians were exposed with a daily noise ex-posure limit exceeding 85dB(A) for 8 hours working shift. The exposure level was currently controlled by practicing the usage of a Personal Hearing Protector (PHP). Thus, this study confirmed that maintenance workers were exposed to high noise levels when performing their maintenance task

Noise risk assessment on noise exposure among urban rail maintenance worker using personal monitoring method

Urban Rail maintenance work usually involves a lot of daily mainte-nance work as proper maintenance must always be a priority for the rail industry to ensure the passengers are always comfortable and safe. These maintenance activities expose the technician to noise as they handle a lot of hand tools and machinery while performing their tasks. Noise Induced Hearing Loss (NIHL) is a major compensable occupational disease in Malaysia due to excessive noise-exposed above the permissible daily noise exposure limit. This study aimed to conduct Personal Monitoring as a part of Noise Risk Assessment (NRA) to meas-ure the level of noise exposure received among maintenance technicians in the excessive noise area. This study focuses on the areas and tasks involved in the Track Network Maintenance Hall (TNMH) and Track Vehicle Storage Building (TVSB) at one of the urban rail companies. Noise Risk Assessment was the se-lected method to measure the level of noise exposure among maintenance tech-nicians in the excessive noise area. The Personal Monitoring method was con-ducted as suggested in the ICOP provided by DOSH Malaysia. Data recorded shows that a total of 2 out of 3 technicians were exposed with a daily noise ex-posure limit exceeding 85dB(A) for 8 hours working shift. The exposure level was currently controlled by practicing the usage of a Personal Hearing Protector (PHP). Thus, this study confirmed that maintenance workers were exposed to high noise levels when performing their maintenance task

Evaluation of cytotoxicity, antimicrobial activity and physicochemical properties of a calcium aluminate-based endodontic material

A calcium aluminate-based endodontic material, EndoBinder, has been developed in order to reduce MTA negative characteristics, preserving its biological properties and clinical applications. OBJECTIVES: The aim of this study was to evaluate the cytotoxicity, antimicrobial activity, pH, solubility and water sorption of EndoBinder and to compare them with those of white MTA (WMTA). MATERIAL AND METHODS: Cytotoxicity was assessed through a multiparametric analysis employing 3T3 cells. Antimicrobial activity against Enterococcus faecalis (ATCC 29212), Staphylococcus aureus. (ATCC 25923) and Candida albicans (ATCC 10556) was determined by the agar diffusion method. pH was measured at periods of 3, 24, 72 and 168 hours. Solubility and water sorption evaluation were performed following ISO requirements. Data were statistically analyzed by ANOVA and Tukey`s test with a significance level of 5%. RESULTS: EndoBinder and WMTA were non-cytotoxic in all tested periods and with the different cell viability parameters. There was no statistical differences between both materials (P>.05). All tested materials were inhibitory by direct contact against all microbial strains tested. EndoBinder and WMTA presented alkaline pH in all tested times with higher values of pH for WMTA (P<.05). Both materials showed values complying with the solubility minimum requirements. However, EndoBinder showed lower solubility than WMTA (P<.05). No statistical differences were observed regarding water sorption (P>.05). CONCLUSION: Under these experimental conditions, we concluded that the calcium aluminate-based endodontic material EndoBinder demonstrated suitable biological and physicochemical properties, so it can be suggested as a material of choice in root resorption, perforations and root-end filling

Extracellular Fibrils of Pathogenic Yeast Cryptococcus gattii Are Important for Ecological Niche, Murine Virulence and Human Neutrophil Interactions

Cryptococcus gattii, an emerging fungal pathogen of humans and animals, is found on a variety of trees in tropical and temperate regions. The ecological niche and virulence of this yeast remain poorly defined. We used Arabidopsis thaliana plants and plant-derived substrates to model C. gattii in its natural habitat. Yeast cells readily colonized scratch-wounded plant leaves and formed distinctive extracellular fibrils (40–100 nm diameter ×500–3000 nm length). Extracellular fibrils were observed on live plants and plant-derived substrates by scanning electron microscopy (SEM) and by high voltage- EM (HVEM). Only encapsulated yeast cells formed extracellular fibrils as a capsule-deficient C. gattii mutant completely lacked fibrils. Cells deficient in environmental sensing only formed disorganized extracellular fibrils as apparent from experiments with a C. gattii STE12α mutant. C. gattii cells with extracellular fibrils were more virulent in murine model of pulmonary and systemic cryptococcosis than cells lacking fibrils. C. gattii cells with extracellular fibrils were also significantly more resistant to killing by human polymorphonuclear neutrophils (PMN) in vitro even though these PMN produced elaborate neutrophil extracellular traps (NETs). These observations suggest that extracellular fibril formation could be a structural adaptation of C. gattii for cell-to-cell, cell-to-substrate and/or cell-to- phagocyte communications. Such ecological adaptation of C. gattii could play roles in enhanced virulence in mammalian hosts at least initially via inhibition of host PMN– mediated killing

Antimicrobial activity of extracts of calcium hydroxide points.

The purpose of this study was to evaluate in vitro the antibacterial effect of calcium hydroxide points by using a broth dilution test. Extracts of calcium hydroxide points and a calcium hydroxide paste (Calasept) were tested by using 2 facultative anaerobic bacteria, Streptococcus mutans (ATCC 27352) and Enterococcus faecalis (ATCC 29212). Saline solution was used as a control. Each tested agent was kept in contact with the bacterial species used for the experiment for 5 minutes, 1 hour, 1 day, 2 days, and 5 days. Results showed that Calasept paste was effective in killing the tested bacteria, whereas calcium hydroxide points and saline showed bacterial survival in all experimental periods. It was concluded that calcium hydroxide points extract is not an effective antimicrobial agent against the tested bacteria.King Saud Universit