scholarly journals Comparing the Air Abrasion Cutting Efficacy of Dentine Using a Fluoride-Containing Bioactive Glass versus an Alumina Abrasive: AnIn VitroStudy

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Melissa H. X. Tan ◽  
Robert G. Hill ◽  
Paul Anderson
Keyword(s):  
Bioactive Glass ◽  
Health And Safety ◽  
Air Abrasion ◽  
X Ray ◽  
Safety Issues ◽  
Outflow Rate ◽  
Caries Removal ◽  
Cutting Efficacy ◽  
Set Up ◽  
Removal Technique

Air abrasion as a caries removal technique is less aggressive than conventional techniques and is compatible for use with adhesive restorative materials. Alumina, while being currently the most common abrasive used for cutting, has controversial health and safety issues and no remineralisation properties. The alternative, a bioactive glass, 45S5, has the advantage of promoting hard tissue remineralisation. However, 45S5 is slow as a cutting abrasive and lacks fluoride in its formulation. The aim of this study was to compare the cutting efficacy of dentine using a customised fluoride-containing bioactive glass Na0SR (38–80 μm) versus the conventional alumina abrasive (29 μm) in an air abrasion set-up. Fluoride was incorporated into Na0SR to enhance its remineralisation properties while strontium was included to increase its radiopacity. Powder outflow rate was recorded prior to the cutting tests. Principal air abrasion cutting tests were carried out on pristine ivory dentine. The abrasion depths were quantified and compared using X-ray microtomography. Na0SR was found to create deeper cavities than alumina (p<0.05) despite its lower powder outflow rate and predictably reduced hardness. The sharper edges of the Na0SR glass particles might improve the cutting efficiency. In conclusion, Na0SR was more efficacious than alumina for air abrasion cutting of dentine.

Health and safety issues among construction workers in Bangladesh

2019 ◽  
Vol 9 (1) ◽  
pp. 13-18
Author(s):  
Firoz Ahmed Mamin ◽  
Ganesh Dey ◽  
Shazal Kumar Das
Keyword(s):  
Health And Safety ◽  
Cross Sectional Study ◽  
Construction Workers ◽  
Safety Equipment ◽  
Cross Sectional ◽  
Safety Issues ◽  
Work Related ◽  
History Of ◽  
Set Up ◽  
Health And Safety Issues

Background: Bangladesh is a rapidly developing country. Lots of infrastructures are set up every year. A large number of people are working in the construction industry.  Work related injuries and deaths of construction workers are common. The aim of this study was to find the health and safety awareness of informal construction workers. Methodology: This study was a cross sectional study by using a preset questionnaire among the construction workers in Bangladesh. Results: Participants of this study had lower income and education. About 87% of participants did not receive any health and safety training and did not wear safety equipment when they were working. About 57% of the participants had a history of injury. This study also found that the main reasons for the non-use of safety equipment were lack of safety equipment, motivation and training. Conclusion: Construction workers are not adequately aware about health and safety issues that relate to them.

scholarly journals Dental caries: Therapeutic possibilities

2008 ◽  
Vol 136 (11-12) ◽  
pp. 662-666
Author(s):  
Tamara Peric ◽  
Dejan Markovic ◽  
Slavoljub Zivkovic
Keyword(s):  
Dental Caries ◽  
Alternative Methods ◽  
Air Abrasion ◽  
Cavity Preparation ◽  
Dental Tissues ◽  
New Methods ◽  
Rotary Instruments ◽  
Caries Removal ◽  
Removal Technique ◽  
Therapeutic Possibilities

Contemporary tendencies in dentistry are based on the concept of maximal protection of healthy tooth tissues. Caries removal has been done traditionally with mechanical rotary instruments that are fast and precise. However, conventional cavity preparation has potential adverse effects to the pulp due to heat, pressure and vibrations. Moreover, drilling often causes pain and requires local anaesthesia, and these procedures are frequently perceived as unpleasant. Etiology, development and prevention of dental caries are better understood today and new restorative materials that bond micromechanically and/or chemically to dental tissues have been introduced. Thus, development of a new, less destructive caries removal technique is allowed. In the last decades, many alternative methods have been introduced in an attempt to replace rotary instruments. These are claimed to be efficient and selective for diseased tissues and to offer comfortable treatment to the patients. New methods include air abrasion, air polishing, ultrasonic, polymer burs, enzymes, systems for chemo-mechanical caries removal, and lasers. The aim of this paper was to discuss various caries removal techniques and possibilities of their use in clinical practice. Based on the literature review it can be concluded that none of the new caries removal methods can completely replace conventional rotary instruments.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Policy Recommendations to Reduce Toxic Exposures for Nail Salon Workers

2011 ◽  
Vol 9 (1-2) ◽  
pp. 43-50 ◽  
Author(s):  
Julia Liou ◽  
Catherine Porter ◽  
Thu Quach
Keyword(s):  
National Level ◽  
Safety Information ◽  
Health And Safety ◽  
Policy Recommendations ◽  
Safety Issues ◽  
Government Oversight ◽  
Regulatory Perspective ◽  
Nail Salon ◽  
Health And Safety Issues ◽  
Nail Salon Workers

The nail salon sector is growing rapidly. Nail salon workers are predominantly Vietnamese immigrant women who are exposed to numerous harmful chemicals in nail care products. The situation is exacerbated by limited safety information, language barriers to information, and lack of government oversight. This brief discusses the health and safety issues faced by workers at the nexus of environmental and worker justice and the policy recommendations by which to address these issues from a public health and regulatory perspective. Although these policy recommendations pertain to California where the sector is largest, they also have far-reaching implications at the national level.

scholarly journals More than XRF Mapping: STEAM (Statistically Tailored Elemental Angle Mapper) a Pioneering Analysis Protocol for Pigment Studies

2021 ◽  
Vol 11 (4) ◽  
pp. 1446
Author(s):  
Jacopo Orsilli ◽  
Anna Galli ◽  
Letizia Bonizzoni ◽  
Michele Caccia
Keyword(s):  
Cultural Heritage ◽  
Element Distribution ◽  
Elemental Distribution ◽  
X Rays ◽  
Spectral Angle Mapper ◽  
X Ray ◽  
Fluorescence Radiation ◽  
Set Up ◽  
Non Destructive ◽  
Analysis Protocol

Among the possible variants of X-Ray Fluorescence (XRF), applications exploiting scanning Macro-XRF (MA-XRF) are lately widespread as they allow the visualization of the element distribution maintaining a non-destructive approach. The surface is scanned with a focused or collimated X-ray beam of millimeters or less: analyzing the emitted fluorescence radiation, also elements present below the surface contribute to the elemental distribution image obtained, due to the penetrative nature of X-rays. The importance of this method in the investigation of historical paintings is so obvious—as the elemental distribution obtained can reveal hidden sub-surface layers, including changes made by the artist, or restorations, without any damage to the object—that recently specific international conferences have been held. The present paper summarizes the advantages and limitations of using MA-XRF considering it as an imaging technique, in synergy with other hyperspectral methods, or combining it with spot investigations. The most recent applications in the cultural Heritage field are taken into account, demonstrating how obtained 2D-XRF maps can be of great help in the diagnostic applied on Cultural Heritage materials. Moreover, a pioneering analysis protocol based on the Spectral Angle Mapper (SAM) algorithm is presented, unifying the MA-XRF standard approach with punctual XRF, exploiting information from the mapped area as a database to extend the comprehension to data outside the scanned region, and working independently from the acquisition set-up. Experimental application on some reference pigment layers and a painting by Giotto are presented as validation of the proposed method.

scholarly journals Evaluation of Self-Reported Agricultural Tasks, Safety Concerns, and Health and Safety Behaviors of Young Adults in U.S. Collegiate Agricultural Programs

Safety ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 44
Author(s):  
J. L. Gibbs ◽  
K. Walls ◽  
C. Sheridan ◽  
D. Sullivan ◽  
M. Cheyney ◽  
...  
Keyword(s):  
Young Adults ◽  
Healthcare Providers ◽  
Health And Safety ◽  
Safety Behaviors ◽  
Medical Provider ◽  
Near Misses ◽  
Safety Issues ◽  
Agricultural Health ◽  
Safety Concerns ◽  
Agricultural Programs

Young adults enrolled in collegiate agricultural programs are a critical audience for agricultural health and safety training. Understanding the farm tasks that young adults engage in is necessary for tailoring health and safety education. The project analyzed evaluation survey responses from the Gear Up for Ag Health and Safety™ program, including reported agricultural tasks, safety concerns, frequency of discussing health and safety concerns with healthcare providers, safety behaviors, and future career plans. The most common tasks reported included operation of machinery and grain-handling. Most participants intended to work on a family-owned agricultural operation or for an agribusiness/cooperative following graduation. Reported safety behaviors (hearing protection, eye protection, and sunscreen use when performing outdoor tasks) differed by gender and education type. Male community college and university participants reported higher rates of “near-misses” and crashes when operating equipment on the roadway. One-third of participants reported discussing agricultural health and safety issues with their medical provider, while 72% were concerned about the health and safety of their family and co-workers in agriculture. These findings provide guidance for better development of agricultural health and safety programs addressing this population—future trainings should be uniquely tailored, accounting for gender and educational differences.

scholarly journals Simple low dose radiography allows precise lung volume assessment in mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amara Khan ◽  
Andrea Markus ◽  
Thomas Rittmann ◽  
Jonas Albers ◽  
Frauke Alves ◽  
...  
Keyword(s):  
Lung Function ◽  
Whole Body ◽  
Acquisition Time ◽  
Micro Ct ◽  
Lung Volumes ◽  
X Ray ◽  
Promising Tool ◽  
Volume Assessment ◽  
Set Up ◽  
Time Required

AbstractX-ray based lung function (XLF) as a planar method uses dramatically less X-ray dose than computed tomography (CT) but so far lacked the ability to relate its parameters to pulmonary air volume. The purpose of this study was to calibrate the functional constituents of XLF that are biomedically decipherable and directly comparable to that of micro-CT and whole-body plethysmography (WBP). Here, we developed a unique set-up for simultaneous assessment of lung function and volume using XLF, micro-CT and WBP on healthy mice. Our results reveal a strong correlation of lung volumes obtained from radiographic XLF and micro-CT and demonstrate that XLF is superior to WBP in sensitivity and precision to assess lung volumes. Importantly, XLF measurement uses only a fraction of the radiation dose and acquisition time required for CT. Therefore, the redefined XLF approach is a promising tool for preclinical longitudinal studies with a substantial potential of clinical translation.

scholarly journals Mass outflow of the X-ray emission line gas in NGC 4151

2020 ◽  
Vol 15 (S359) ◽  
pp. 131-135
Author(s):  
S. B. Kraemer ◽  
T. J. Turner ◽  
D. M. Crenshaw ◽  
H. R. Schmitt ◽  
M. Revalski ◽  
...  
Keyword(s):  
Emission Line ◽  
Total Mass ◽  
High Energy ◽  
Model Parameters ◽  
Zeroth Order ◽  
Space Telescope ◽  
X Ray ◽  
Ngc 4151 ◽  
Outflow Rate ◽  
Mass Outflow

AbstractWe have analyzed Chandra/High Energy Transmission Grating spectra of the X-ray emission line gas in the Seyfert galaxy NGC 4151. The zeroth-order spectral images show extended H- and He-like O and Ne, up to a distance r ˜ 200 pc from the nucleus. Using the 1st-order spectra, we measure an average line velocity ˜230 km s–1, suggesting significant outflow of X-ray gas. We generated Cloudy photoionization models to fit the 1st-order spectra; the fit required three distinct emission-line components. To estimate the total mass of ionized gas (M) and the mass outflow rates, we applied the model parameters to fit the zeroth-order emission-line profiles of Ne IX and Ne X. We determined an M ≍ 5.4 × 105Mʘ. Assuming the same kinematic profile as that for the [O III] gas, derived from our analysis of Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra, the peak X-ray mass outflow rate is approximately 1.8 Mʘ yr–1, at r ˜ 150 pc. The total mass and mass outflow rates are similar to those determined using [O III], implying that the X-ray gas is a major outflow component. However, unlike the optical outflows, the X-ray emitting mass outflow rate does not drop off at r > 100pc, which suggests that it may have a greater impact on the host galaxy.

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