122 research outputs found
Comparative Effect of Honey Bee Venom and Common Antifungal Agents on Candida albicans
Fungal infections, can cause various symptoms in different forms, and are associated with high morbidity and mortality in vulnerable groups. one of the most significant fungal infection is candidiasis which caused by Candida. In recent years, there has been growing worried about the challenging of fungal diseases treatment and unwanted consequence of synthetic antifungal drugs. This necessitates the searching for new classes of broad-spectrum anti-fungal drugs to bring pharmaceutical characteristics and more efficient treatments. Bee venom (BV) is an antimicrobial agent which has been widely used to treat various diseases. the aim of the current study was to examine the antifungal properties of honey bee venom on Candida albicans to compare it to some common antifungal drugs (ketoconazole and amphotericin B). to perform this assay, the standard strains of C. albicans (ATCC10231) was used for antimicrobial assessment, and Disc diffusion assay and the microbroth dilution method were used to evaluate the anti fungal activity of (BV). The result of this study showed that BV, amphotericin B and ketoconazole had inhibitory effects on C. albicans which MIC of the were measured to be 118.2, 3.3 and 2 respectively, furthermore, Comparison of BV and common antifungal drugs demonstrated that, amphotricin B and ketoconazole have a better effect on C. albicans
Characterization of 1, 4, 7-Trithiacyclononane, [9]aneS3 as a Potential Toxic Heavy Metal Chelator
Toxic heavy metal poisoning with metals including lead, mercury, and cadmium, whether in the environment or through ingestion, remains a persistent problem. Remediation of metal contamination and poisoning has generally been treated with chelating agents that bind metals, rendering them inert, and allow for easier removal. Chelation involves the formation of two or more separate coordinate covalent bonds between a polydentate ligand and a single central atom. However, chelators are not without side effects. Due to the similar size of metal ions and lack of specificity of ligands, chelators can also remove beneficial metals like iron and zinc from the body. This thesis focuses on identifying macrocyclic chelators that will bind specifically to toxic heavy metals and not physiologically important transition metals such as iron and zinc. It is well known that toxic metals have an affinity for sulfurs and therefore macrocyclic thiaethers are potential chelating agents for these toxic metals. The macrocycle 1,4,7-Trithiacyclononane ([9]aneS3) is the ligand of interest for this study due to its small cavity size. Previous studies (unpublished) indicated that [9]aneS3 binds mercury very strongly. This study probes further into the strength of metal-ligand complexes of 1,4,7-Trithiacyclononane with first row transition metals by using absorbance values measured with UV-Visible spectroscopy. Stability constant calculations were performed based on the McConnell-Davidson equation. Molar extinction coefficients (€) of M([9]aneS3)2 2+ complexes were determined to be in the range of 10000 – 34000 M-1 cm-1 . The stability constants (log β) of M([9]aneS3)2 2+ were found to be in the range of 1.4– 4.9 (Table 7). These results show that the chelator, 1,4,7-Trithiacyclononane binds several first row transition metal ions weakly. This weak binding with transition metals yet strong binding with mercury suggests that 1,4,7-Trithiacyclononane may function as a potential selective chelator for mercury. The ratio of metal to ligand complexes was also determined using Job’s plot analysis. Results show that first row transition metals bind to the ligand in a ratio of 1:2. This suggests that the ligand 1,4,7-Trithiacyclononane, presumably binds metal ions in an octahedral geometry, where the metal ion is sandwiched between two molecules of ligands. In this preferential geometry the metal ion is bound to six sulfur atoms from two ligand molecules. Taken together, these results help us understand binding preferences and mechanisms of transition metals and toxic heavy metals towards macrocyclic thiaethers
Galvanic Corrosion between Various Combinations of Orthodontic Brackets and Archwires
Introduction: The purpose of this study was to compare galvanic currents generated by different combinations of commonly used brackets and archwires.
Methods: As-received stainless steel, nickel-titanium, and betatitanium wires were coupled to stainless steel and titanium brackets in an artificial saliva medium. The galvanic current and amount of charge transferred for each pair were monitored with a zero resistance ammeter for 10 hours.
Results: Two-way analysis of variance (ANOVA) showed a significant difference in charge and galvanic currents when factored for type of bracket (P\0.001), but no significant difference between them when factored by type of wire (P .0.05). Specifically, a brazed stainless steel bracket was significantly greater in charge transferred and 10-hour galvanic current than metal injection molded stainless steel and titanium brackets (P\0.001), which were not different from each other (P .0.05).
Conclusions: The method of bracket manufacturing might be of equal or more relevance to galvanic corrosion susceptibility than bracket composition
Determinants of hookah smoking among men in the coffee houses : an application of socio-ecological approach
Background: Tobacco smoking is the second leading cause of death and is closely linked to fatal diseases. Hookah Smoking (HS) is a traditional way to smoke tobacco, especially in the Eastern Mediterranean region that is constantly rising around the world. This study aimed to evaluate the different levels of personal, interpersonal and social HS in Iranian urban men and determine the most important predictors of the levels through applying the socio-ecological approach (SEA).
Methods: This study was conducted in the coffee houses of Hashtrud and Qarah Aghaj counties in East Azerbaijan, Iran. Data collection was conducted from the entire coffee house (n = 18) from April to June 2017. Systematic sampling was employed to recruit 266 men in the coffee house. A valid and reliable instrument was used to investigate the frequency of HS and its determinants based on SEA. The SEA consists of three levels: personal (age, education, employment, income, and perceived severity and sensitivity), interpersonal (perceived reward), and social level (social support) intended to assess HS determinants. Hierarchical regression was used to determine the predictive value of SEA levels and frequency of HS.
Results: The mean age of daily hookah smokers (once per day and more than once per day) were (26.8) significantly lower than those (30.4) smokes weekly (once a week or more than once a week). The hierarchical logistic regression model showed that in the first step individual variables significantly predict 25.1% HS. In the second and third level interpersonal and social levels of SEA explained HS 30.1 and 30.8%, respectively.
Conclusion: This study found that age, income, education, and perceived reward were all important factors influencing HS among men youth. Application of SEA to determine the factors associated with HS could contribute in the development of a holistic prevention program
Experimental Racetrack Shaped Jet Impingement on a Roughened Leading-Edge Wall With Film Holes,”
study are: (a) for a given jet Reynolds number, the racetrack crossover jets produce a higher impingement heat transfer coefficient than the circular jets, (b) the overall heat transfer performance of 0 o racetrack crossover jets is superior to that of 45 o racetrack crossover jets and (c) there is a heat transfer enhancement benefit in roughening the target surface. With the presence of showerhead holes, the enhancement is due to both the impingement heat transfer coefficient and the heat transfer area increase. NOMENCLATURE ABSTRACT Compatible with the external contour of the turbine airfoils at their leading edge, the leading-edge cooling cavities have a complex cross-sectional shape. To enhance the heat transfer coefficient on the leading-edge wall of these cavities, the cooling flow in some designs enters the leadingedge cavity from the adjacent cavity through a series of crossover holes on the partition wall between the two cavities. The crossover jets then impinge on the concave leading-edge wall and exit through the showerhead film holes, gill film holes on the pressure and suction sides, and, in some cases, form a crossflow in the leading-edge cavity and move toward the airfoil tip. The main objective of this investigation was to study the effects that racetrack crossover jets, in the presence of film holes on the target surface, have on the impingement heat transfer coefficient. Available data in open literature are mostly for impingement on a flat smooth surface with no representation of the film holes. This investigation covered new features in airfoil leading-edge cooling concept such as impingement with racetrack shaped holes on a roughened target surface with a row of holes representing the leading-edge showerhead film holes. Results of the circular crossover jets impinging on these leading-edge surface geometries with and without showerhead holes were reported by these authors previously. In this paper, however, the experimental results are presented for the impingement of racetrack-shaped crossover jets on a concave surface with showerhead film holes. The investigated target surface geometries were : (1) a smooth wall, (2) a wall roughened with big conical bumps, (3) a wall roughened with smaller conical bumps and (4) a wall roughened with tapered radial ribs. The tests were run for a range of flow arrangements and jet Reynolds numbers and the results were compared with those of round crossover jets. The major conclusions of thi
Risk perception related to COVID-19 among the Iranian general population : an application of the extended parallel process model
Background
The novel coronavirus disease 2019 (COVID-19) has emerged as a major global public health challenge. This study aimed to investigate on how people perceive the COVID-19 outbreak using the components of the Extended Parallel Process Model (EPPM) and to find out how this might contribute to possible behavioral responses to the prevention and control of the disease.
Methods
This cross-sectional study was conducted in Iran during March and April 2020. Participants were recruited via online applications using a number of platforms such as Telegram, WhatsApp, and Instagram asking people to take part in the study. To collect data an electronic self-designed questionnaire based on the EPPM was used in order to measure the risk perception (efficacy, defensive responses, perceived treat) related to the COVID-19. Descriptive statistics, chi-square, t-test and analysis of variance (ANOVA), were used to explore the data.
Results
A total of 3727 individuals with a mean age (SD) of 37.0 (11.1) years participated in the study. The results revealed significant differences in efficacy, defensive responses and perceived treat among different population groups particularly among those aged 60 and over. Women had significantly higher scores than men on some aspects such as self-efficacy, reactance, and avoidance but men had higher perceived susceptibility scores compared to women. Overall 56.4% of participants were engaged in danger control (preventive behavior) while the remaining 43.6% were engaged in fear control (non-preventive behavior) process.
Conclusion
More than half of all participants motivated by danger control. This indicated that more than half of participants had high perceived efficacy (i.e., self-efficacy and response efficacy). Self-efficacy scores were significantly higher among participants who were older, female, single, lived in rural areas, and had good economic status. The results suggest that socioeconomic and demographic factors are the main determinants of the COVID-19 risk perception. Indeed, targeted interventions are essential for controlling the pandemic
Depression and anxiety in sterilised women in Iran
Sterilisation is an effective and convenient means of contraception and has become increasingly popular as a birth control technique throughout the world during the past 40 years. However some women who choose sterilisation may suffer a neurotic syndrome, which is manifested in the form of pain, depression and loss of libido.1We undertook a study designed to investigate depression, anxiety and post-operation regret rate in sterilised women referred to health centres in Tabriz, Iran in 2006. The study design was descriptive-analytical. The study participants comprised 300 women in the age range 25–45 years, of whom 150 women were sterilized between 1 and 10 years ago and 150 were a control group of non-sterilised women who used condoms, withdrawal or safe period methods for contraception. The control group was selected by a cluster random sampling method. Fifteen health centres were selected as a cluster from 96 health centres located in Tabriz. Ten women were selected randomly from each health centre using health documents. Women were eligible for inclusion in the study if they were aged between 25 and 45 years at the time of sampling, and if they had no history of psychological disorders and no recent sorrowful events. There were no differences between the two groups as regards the number of children, income or demographic characteristics. The women were contacted by telephone at
their last known address and were asked to complete questionnaires. Data collection was done using Zung’s self-rating depression and anxiety scale in addition to questions about post-sterilisation regret. Data were collected from the subjects anonymously and analysed using SPSS (v. 11.5) statistics software. Analysis employed t-test, Chi-square test and
descriptive statistics. The comparison of the means for depression in the two groups was not significantly different
(p = 0.96), however the mean of anxiety in the case group was remarkably greater than the control group (p = 0.03). Insufficient poststerilisation rest was a significant risk factor for depression and anxiety (p = 0.008 and p = 0.02,
respectively). Requesting information about reversal after tubal sterilisation was 2.7% and the post-sterilisation regret rate was 6%, which was significantly related to women’s conflict with their husbands about the decision-making process
prior to sterilisation (p<0.001). The study findings as regards psychological disorders of sterilisation suggested that women undergoing sterilisation should ensure that they have a good rest after their operation in order to reduce the extent of psychological disorders. Unlike studies undertaken in other countries,2–4 women’s age, parity, marriage duration and the timing of sterilisation was unrelated to the women’s regret in our study. The earlier the sterilisation is carried out, the longer the woman’s remaining period of fertile life and the greater the chances of changes in her marital status and/or
the loss of a child, both circumstances that may lead to a change in the desired family size and expression of regret. In our study, probably one of the reasons why women’s regret did not appear to be significantly related to young age of
sterilisation was the infrequency of divorce or remarriage in our study population. Consistent with our study, Jamieson et al. reported that women who had substantial conflict with their husbands or partners prior to sterilisation were
more than three times as likely to regret their decision and more than five times more likely to request a reversal than women who did not report such conflict.5 In our study, pre-sterilisation counseling was reported by 29.3% of subjects. With respect to personality and adaptability differences in facing the changes, pre-sterilisation counseling and post-sterilisation follow-up systems have an important role to play in women’s psychological and psychosexual health promotion
Borehole Geology and Alteration Mineralogy of Well NWS-4, Mt.Sabalan Geothermal Field, NW-Iran Masoud Eshaghpour Renewable Energy Organization of Iran (SUNA)
ABSTRACT Drilling of well NWS-4 was finished in 29 March 2004 during 98 day at western side of Sabalan Volcano in Northwest of Iran. Refer to MT results, there is <4Ωm anomaly beneath the western side of Moil valley with about 500m thickness. Lithology of the well consists of Lava flows and volcanic ash and hypabyssal rocks in the lower parts of the well. Surface deposits are unaltered and in lower parts, secondary hydrothermal minerals mainly consist of clays, Silica, Pyrite and in lower parts and quartz, clay, magnetite and epidote in high temperature zone. Heat up test in 4rth day survey shows the maximum temperature at T.D (211 o C) and also behind of production casing there is high enough (about 205 o C). After 1612 m depth there is tectonized permeable zone due to encountered faults. At 1220m depth and 1620m there are 2 cooler zones created by faults. At 950m depth there is a clear increase in high temperature hydrothermal minerals as epidote that 4th heat up test emphasized it. Correlation between measured temperature and alteration temperature indicates that alteration temperature is close to measured temperature at maximum of about 230oC in interval 950-1170m depth
Comparison of antibacterial activity of essential oils of Foeniculum vulgare Mill, Mentha arvensis and Mentha piperita against Streptococcus mutans
Background and aims: Tooth decay is one of the most common chronic diseases around
the world and this problem is the result of variety of different bacteria. Streptococcus
mutants is one of the most important bacteria which is related to this disease. Finding
new effective antibacterial agents is an important area in bioscience for fighting and
controlling bacterial infections. Essential oils are most important natural sources of
antibacterial agents, particularly against drug-resistant bacteria.
Methods: The aim of this study was to evaluate and compare the antibacterial activity of
three essential oils Mentha arvensis, Mentha piperita and Foeniculum vulgare Mill
against Streptococcus mutants. Disk diffusion method was carried out and the minimum
inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were
measured.
Results: The results showed that all three essential oils have antibacterial activity against
S. mutants. With a constant concentration of 100 µg/µl, the efficiency of Mentha piperita
and then Foeniculum vulgare Mill was higher than the efficiency of Mentha arvensis at
all 3 given time points (24, 48 and 72 hours). The most effective MIC and MBC were
related to Streptococcus mutants using Foeniculum vulgare essential oil which were
equal to 8.4 and 14.9 µg/ml, respectively. MIC and MBC for Mentha piperita essential
oil were measured 10.5 and 16.3 µg/ml, respectively.
Conclusion: The Essential oils used in present study with different components showed
antibacterial activity and therefore they can be used as new antibacterial substances
Chemical composition and antibacterial activity of some herbal essential oils against Streptococcus mutans
Background and aims: One of the most common chronic diseases in the world is tooth decay. A variety of bacteria are involved in this disorder of which Streptococcus mutants is the most common. Essential oils are considered as new natural compounds for use in combating drug-resistant bacteria. This study was aimed to evaluate the antibacterial activity of some essential oils prepared from Eucalyptus caesia Benth, Cuminum cyminum L. and Satureja hortensis L. on S. mutants. Methods: In this study, essential oils were extracted by hydrodistillation method. E. caesia Benth, C. cyminum L. and S. hortensis L. were characterized by using gas chromatography‒mass spectrophotometry (GC‒MS). Antibacterial activity indices including minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and zone of inhibition for the above essential oils against Streptococcus mutans were determined using broth macro-dilution and disk diffusion methods. Data analysis was performed using one-way ANOVA and Tukey test. Results:Results showed that all three extracts had antibacterial activity against S. mutants. S. hortensis L. essential oil with the lowest MIC and MBC value (13.2 and 18.4 µg/ml, respectively) and the biggest inhibition zone showed the strongest antibacterial effect against S. mutants in all exposure times and at all concentrations, compared with two other essential oils. Furthermore, C. cyminum L. essential oil had higher anti-bacterial activity against S. mutant than E. caesia Benth essential oil. Conclusions:The essential oils used in the present study with different components showed antibacterial activity (especially S. hortensis L essential oil), and therefore they can be used as a new antibacterial substance. Keywords: Dental caries, Streptococcus mutans, Essential oils, Antimicrobial
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