Effects of Chlorhexidine and Sodium Hypochlorite on the Setting Time of Calcium-Enriched Mixture Cement

Introduction: The aim of the present study was to evaluate whether adding 2% chlorhexidine (CHX) and 2.6% sodium hypochlorite (NaOCl) to calcium-enriched mixture (CEM) cement would affect its setting time (ST), or not. Methods and Materials: In this study, the setting time of CEM cement was evaluated in three groups (n=9) as follows: group 1; CEM cement, group 2; CEM cement+2% CHX and group 3; CEM cement+2.6% NaOCl. Then the mean values of ST were calculated and the Kolmogorov-Smirnov test was used to evaluate the normal distribution of data. The Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis. Statistical significance was set at 0.05. Results: The mean ST for groups 1, 2 and 3 were 105, 120 and 220 min, respectively. There was a significant increase in the duration of ST in group 3 (NaOCl) in comparison with the two other groups (P<0.05). Conclusion: NaOCl significantly increased the ST of CEM cement, whereas chlorhexidine did not alter the ST.Keywords: Calcium-Enriched Mixture; CEM Cement; Chlorhexidine; Setting Time; Sodium Hypochlorit

Investigating the Trend of Dust Changes in The Eastern Half of Iran

IntroductionThe impact of dust storms on the ecosystem, human health, and economy is significant in the affected areas. In arid and semi-arid regions, dust is a natural occurrence that covers about one third of the earth's surface. This phenomenon is caused by wind erosion and factors such as the size of soil particles and their adhesion force, surface roughness, weather conditions such as long-term droughts cause it to intensify. To understand the impact of the dust phenomenon on humans and the environment, it is essential to evaluate the spatial and temporal distribution of dust and its changes and effects. Numerous studies have been carried out in the field of evaluating dust changes using different methods. For example, using CMIP5 models, synoptic fog systems are predicted to increase during the 21st century in the Middle East. In addition, using AOD obtained from MODIS and MERRA-2 sensors, researchers showed a significant upward trend in dust changes from 2000 to 2010. A significant upward trend was shown in Iran's winter AOD values during the period 2000 to 2010, and a decreasing trend during the period 2010 to 2018. A point can be spotted by examining various studies in the Middle East and Iran that evaluate the spatio-temporal changes of dust. Statistical tests of time series study, such as Mann-Kendall spatially and pixel by pixel, have been used in limited research to evaluate the trend of dust changes. In Iran, there is a research gap in not using spatial and pixel-by-pixel statistical tests to evaluate the trend of dust changes, as stated. This research aimed to provide a solution and address the problem by analyzing the spatial and temporal changes of dust using the AOD index in the eastern half of the country. Material and Methods In this research, in order to evaluate the temporal-spatial changes of dust, the AOD data of the blue band (470 nm) of the MCD19A2 product of the MODIS sensor was used. AOD parameter is known as one of the most key factors in studying the climatic effects of aerosols and atmospheric pollution. In order to extract AOD data, monthly data from 2001 to 2022 were obtained in the Google Earth Engine system by averaging the daily AOD data. Over a 22-year period, the average of each month was calculated. The months that had the highest average AOD values were chosen and their changes were evaluated. In this research, the Mann-Kendall test was used to evaluate the change process. Menkendall's ZM coefficient was calculated for months in the Earth Trend Modeler (ETM) of the TerrSet software to achieve this. In the next step, the intensity of monthly AOD changes per time unit was calculated for 22 years in selected months. To simulate the process of changes, linear regression analysis can be utilized for this purpose. This method is used to determine the linear relationship between all the data of a dependent variable and the corresponding data of the independent index. If the slope is higher than zero, the dependent variable will change in the same direction as the independent variable. The dependent variable changes in the opposite direction of the independent variable if the slope is smaller than zero. The steeper the slope of changes, the greater the impact of the independent variable on the dependent variable. The Earth Trend Modeler (ETM) of TerrSet software also carried out this step. Results and DiscussionBased on the evaluation of the monthly average AOD changes in the studied area, the trend and intensity of AOD changes from 2001 to 2022 were assessed in April, May, June, and July. In most areas of the studied area, AOD is increasing with a probability of more than 70%, and the intensity of changes is mostly high and very high in April. It can be concluded that AOD is experiencing a strong increase in April. This is despite the fact that in May, June and July, respectively, a considerable part of the western half, northern half and eastern half is increasing with different intensities with a probability of more than 70%. It can be concluded that the trend and intensity of AOD changes in the above-mentioned months follow a different spatial pattern. The dispersion of dust production centers inside and outside Iran, and the local and regional synoptic conditions governing dust production centers is the cause of changes in the spatio-temporal patterns of dust storms. The unprincipled extraction of water resources by humans, land degradation, soil moisture reduction, and the loss of vegetation due to climate change all affect these factors in turn. The results showed that the monitoring of monthly average AOD changes can help to identify new hotspots and evaluate the results of wind and dust erosion control and management activities. Therefore, it can be suggested that a system based on remote sensing must be designed and presented to monitor dust changes, so that the management of the dust phenomenon in Iran becomes more. We need to pay attention to the factors that influence these changes and evaluate their impact on the dust phenomenon.  On the other hand, by modeling the environmental factors affecting on the trend of dust changes in each region by using methods such as dust evaluation, it is possible to determine the role of each factor and the most important factor affecting the trend of dust changes in each region

Sensitivity to Antibiotics of Bacteria Exposed to Gamma Radiation Emitted from Hot Soils of the High Background Radiation Areas of Ramsar, Northern Iran

Background: Over the past several years our laboratories have investigated different aspects of the challenging issue of the alterations in bacterial susceptibility to antibiotics induced by physical stresses. Objective: To explore the bacterial susceptibility to antibiotics in samples of Salmonella enterica subsp. enterica serovar Typhimurium (S. typhimurium), Staphylococcus aureus, and Klebsiella pneumoniae after exposure to gamma radiation emitted from the soil samples taken from the high background radiation areas of Ramsar, northern Iran. Methods: Standard Kirby-Bauer test, which evaluates the size of the zone of inhibition as an indicator of the susceptibility of different bacteria to antibiotics, was used in this study. Results: The maximum alteration of the diameter of inhibition zone was found for K. pneumoniae when tested for ciprofloxacin. In this case, the mean diameter of no growth zone in non-irradiated control samples of K. pneumoniae was 20.3 (SD 0.6) mm; it was 14.7 (SD 0.6) mm in irradiated samples. On the other hand, the minimum changes in the diameter of inhibition zone were found for S. typhimurium and S. aureus when these bacteria were tested for nitrofurantoin and cephalexin, respectively. Conclusion: Gamma rays were capable of making significant alterations in bacterial susceptibility to antibiotics. It can be hypothesized that high levels of natural background radiation can induce adaptive phenomena that help microorganisms better cope with lethal effects of antibiotics

Effect of pre-wetted perlite and fibers on autogenous and plastic shrinkage of high strength concrete

This thesis deals with the mitigation of plastic shrinkage in high strength concrete through internal curing and fiber reinforcement. In addition, the effects of mixture proportioning, internal curing and fiber reinforcement on elimination of autogenous shrinkage in mortar were studied. Internal curing can prevent cement paste from self-desiccation by providing small water reservoirs within the mortar or concrete. Fiber reinforcement can potentially increase the early age tensile strength. Plastic shrinkage cracks were observed only on the control concrete specimens. That is, the addition of fibers and partial replacement of fines with pre-wetted perlite both provided viable mechanisms to mitigate or reduce plastic shrinkage in high strength concrete. The fibers had a negligible effect on compressive strength. However, there was a significant decrease in compressive strength for mixes containing 25% perlite by volume of fine aggregate. Based on these results, 0.15% fibers by volume appears to be more useful than 25% perlite by volume for mitigating plastic shrinkage in high strength concrete. The mixes without pre-wetted perlite underwent autogenous shrinkage; while the internally cured mixes underwent some swelling. That is, partial replacement of fines with pre-wetted perlite provided viable mechanism to completely eliminate autogenous shrinkage in high strength mortar. The mortar mix with fly ash exhibited the least amount of autogenous shrinkage. Therefore, in cases where addition of pre-wetted perlite is not desirable due to the loss in mechanical properties, sacrifices, fly ash can be considered as a good replacement for internal curing agent.Applied Science, Faculty ofCivil Engineering, Department ofGraduat

Life cycle assessment of Frederic Lasserre Building at University of British Columbia

The LCA analysis of Frederick Lasserre building was conducted using the OnScreen TakeOff Pro software to perform analysis on the structural drawing of the Frederick Lasserre building. The data collected from OnScreen TakeOff pro are then entered into the Impact Estimator (IE). The environmental impact of the data is then quantified through IE which uses the Athena LCI database and the TRACI impact assessment methodology. Bill of Material (BoM), Summary Measures and Absolute Energy reports which were generated by IE were used in the environmental impact analysis of the Frederick Lassere building. These reports were used to perform sensitivity analysis and building performance on the Frederick Lasserre building. BoM report which is a list of the materials which were used in construction of the building and summary measure report data were used in sensitivity analysis. Through this analysis it was found that rebar has the highest environmental impact out of five other materials which were chosen from the Lasserre building for the purpose of sensitivity analysis. The building performance analysis was done on the original Frederick Lasserre building and the upgraded Lasserre building. The upgraded Lasserre building surface areas where insulated so that the building meets the REAP standards. It was found that the energy payback period of the improved Lassere building would be 4 months. From the analysis, it is recommended that further research be conducted into envelope performance upgrades. Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”Applied Science, Faculty ofCivil Engineering, Department ofUnreviewedUndergraduat

Intercomparisons of some dust models over West Asia

Evaluation and assessment of dust model results is of primary importance to get a better understanding of the models' performance, and therefore, enhancing the models' set up and structure. Besides some SDS-WAS dust models, two other high resolution WRF-Chem runs have been carried out for two dust episodes over the West Asia with alterations in the soil erodibility fields as one of the primary criteria of dust sources. The main aim of this article was to investigate the high resolution WRF-Chem modeling with the default and altered soil erosion, against the WMO SDS-WAS models. In this paper we investigated the application of WRF-Chem dust modeling for the region of interest (Iran), which cannot be seen entirely by the SDS-WAS models' domains. Comparisons of modelled dust surface concentrations with ground based measurements on 8 air quality stations show that the high resolution WRF-Chem could more or less lead to better predictions. For some cases, the results of the high resolution WRF-Chem unexpectedly presented a declined performance, which indicate that the improvements in the horizontal resolution and soil erodibility could not always lead to improved dust predictions, and more factors such as the model set-up and structure should be considered

A Novel Multiplex LAMP Assay for the Rapid and Accurate Diagnosis of Visceral Leishmaniasis Caused by Leishmania infantum from Iran

Visceral leishmaniosis (VL) is one of the neglected tropical diseases despite being responsible for serious clinical symptoms, some of which lead to fatal outcomes. Thus, there is a need to apply accurate, rapid, and specific diagnostic measurements in order to control the disease and reduce the mortality rate. We aimed to develop and validate a multiplex LAMP assay for the diagnosis of VL caused by Leishmania infantum (L. infantum). Moreover, a thorough assessment was conducted to determine the effectiveness of multiplex LAMP in identifying various Leishmania species, such as Leishmania tropica (L. tropica) and Leishmania major (L. major) in comparison to Leishmania infantum (L. infantum). The diagnostic performance of the multiplex LAMP method for VL was compared to each LAMP assay, real-time polymerase chain reaction (RT-qPCR), and nested PCR technique. Two separated primers were set and used in a multiplex LAMP assay which was designed based on the ITS2 (internal transcribed spacer II) and were selected on the basis of conserved and high copy number region. Multiplex LAMP primers were designed using an online tool available at https://www.primerexplorer.jp/e. The alignment was performed using MEGA5, and the primers were further adjusted utilizing GENE Runner software. All molecular methods were tested on the serial dilution of cloned plasmid containing ITS region from standard strains of L. infantum, L. tropica, and L. major. Moreover, multiplex LAMP assay was evaluated and compared based on both standard strains and 55 clinical samples from humans as well as dogs. Various approaches were applied to interpret the multiplex LAMP reaction which deciphered a higher sensitivity when compared to the RT-qPCR for L. infantum (one copy number of plasmid, equal to 0.85 femtograms (fg) of plasmid concentration, and 0.004 parasite DNA per μL) detection while these three standard strains of Leishmania were confirmed to contain 40 DNA copies using RT-qPCR. Additionally, the multiplex LAMP detection limit was approximately equivalent to RT-qPCR for L. major and L. tropica, which included 0.342 picograms (pg) and 342 femtograms (fg) of plasmid concentration, 4 × 103 and 4 × 102 copy number of plasmid, and 17.1 and 1.71 parasite DNA per μL for L. major and L. tropica, respectively. Nested PCR exhibited a lower detection limit for L. infantum of 4 × 106 plasmid copy number compared to multiplex LAMP and RT-qPCR. Multiplex LAMP has the potential for accurate and rapid detection of infectious disease, successful treatment, and finding and monitoring asymptomatic cases, especially in low-income countries

Drug-related community issues and the required interventions in open drug scenes in Tehran, Iran: a qualitative study protocol

Background and objectivesMany low-income and middle-income countries experience problems with open drug scenes and drug-related community issues (DRCIs). These experiences occur in settings with varying levels of health and law enforcement initiatives, and accordingly a range of approaches are implemented to curb the problem. Most of the published literature stems from Western and high-income societies. With this concern, the present study aims to describe a planned project to explore DRCIs in the open drug scenes of Tehran, including its typology, and predisposing and reinforcing factors. In addition, the study attempts to investigate the perceptions with respect to the required interventions and barriers to their accessibility.To this end, the current study focuses on the Farahzad drug scene due to its structure and the difficult access to the scene by harm reduction providers. Data collection techniques encompass field observation, indepth interview and focus group discussion. Further, semistructured interviews are conducted with people who use drugs and other key informants who are engaged at this drug scene, including business, community, voluntary and statutory stakeholders, for an average of 90 min (average of 45 min for each part of the study). Furthermore, as a complementary method, field observation is performed regarding the themes of DRCIs at this scene. Then, focus group discussions are held to further describe the themes of DRCIs as well as to explore the required interventions, for an average of 90 min. Finally, the results are evaluated using qualitative content analysis.Ethics and disseminationEthical approval for the study was obtained from the Ethics Committee of Iran University of Medical Sciences, Iran. Additionally, participants are to provide written informed consent. The findings of the study are expected to play a role in promoting the current intervention

Vaccine design and delivery approaches for COVID-19

COVID-19 is still a deadly disease that remains yet a major challenge for humans. In recent times, many large pharmaceutical and non-pharmaceutical companies have invested a lot of time and cost in fighting this disease. In this regard, today's scientific knowledge shows that designing and producing an effective vaccine is the best possible way to diminish the disease burden and dissemination or even eradicate the disease. Due to the urgent need, many vaccines are now available earlier than scheduled. New technologies have also helped to produce much more effective vaccines, although the potential side effects must be taken into account. Thus, in this review, the types of vaccines and vaccine designs made against COVID-19, the vaccination programs, as well as the delivery methods and molecules that have been used to deliver some vaccines that need a carrier will be described