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Background: Members of the Malassezia genus are often lipophilic, observed as budding yeasts and found as commensals in the skin of humans. This genus opportunistically reside in several areas including scalp where under the influence of particular predisposing factors, their proliferation is increased (e.g., high activation of sebaceous glands), and leads to dandruff and seborrheic dermatitis, which together affects >50% of human beings. The proliferation of yeasts in scalp creates health and hair hygiene problems. In this study we determined the type and frequency of Malassezia species in scalp dandruff in order to have epidemiologic and therapeutic understanding. Materials and Methods: Differentiation tests were done for scalp samples, including: morphology, Tween 20, 40 and 80 assimilation tests, hydrolysis of bile-esculin, catalase and growth on Sabouraud dextrose agar with chloramphenicol and cycloheximide (SCC) and sediment production on mDixon agar medium. Results: Frequency of various Malassezia species from 140 scalp samples from volunteers of both gender were found as: M. globosa (46.5%), followed by M. furfur (27.0%), M. restricta (12.7%), M. sympodialis (6.5%) and M. slooffiae (0.8%). Conclusion: In view of high prevalence ofM. globosa, its invasive characteristics and the role of predisposing factors in the more proliferation of this species in scalp should be considered.

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Background: Many comprehensive epidemiological studies have been done about fungal infections, which areone of the publichealth and therapeutic problemsin different communities. Since prevalence rate of fungal diseases and their etiological agents are changing over time,the aim of this study was to provide additional information about visceral fungal infections (VFIs) in order to understand the ways of their dissemination, to prevent disease transmission, to eliminate contamination sources and predisposing factors, and to provide effective ways for their treatment.
Materials and Methods: Samples were taken from the lesion of patients referred to medical mycology laboratory of Tehran University of Medical Sciences from 2014 to 2015. After providing direct wet mount of Potassium hydroxide (KOH) smears from these samples and samples sent from other medical centers, culturing on Sabouraud Dextrose agar with chloramphenicol (SC) and brain heart infusion agar (BHI) media was performed. After growth, species were identified.
Results: From a total of 295 suspected samples, VFI was proved in 69 cases (23%). Aspergillosis was the most prevalent infection among VFIs. Candidiasis, cryptococcosis and mucormycosis were in the late orders, respectively. Two patients were also infected by Trichosporon. The predominant species in aspergillosis infections was Aspergillus flavus, and the predominant species in candidiasis infections was Candida albicans.
Conclusion: According to the obtained results on the prevalence rate and incidence of VFIs between male and female patients in different age groups and also by taking into account the prevalent type of fungi and infectious site of patients’ bodies, it is possible to take appropriate action for the prevention and treatment of these kinds of diseases by using the important keys of these results to research and study etiological and underlying factors involved in these diseases.

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Background: Many studies have been conducted on fungal infections which are known as public health and therapeutic problems. Since the prevalence rate of the fungal diseases and their etiological factors are changing over time, the purpose of this study was to identify the prevalence rate of superficial-cutaneous fungal infections (SCFIs) in order to understand the ways of their dissemination, to prevent diseases transmission, to eliminate contamination sources and predisposing factors, and to take appropriate action for their treatment.
Materials and Methods: After referral to medical mycology laboratory of Tehran University of Medical Science from 2014 to 2015, the patients were subjected to mycological examinations, and sampling of patients’ lesions was performed. Directsmears were prepared with Potassium hydroxide. Samples were cultured on Sabouraud dextrose agar medium, and species were identified.
Results: From a total of 916 suspected patients, 334 cases (36.5%) had SCFIs. Dermatophytosis was the most prevalent SCFI (55.7%), followed by cutaneous candidiasis (19%), tinea versicolor (14.3%), and non-dermatophytic molds (11%).Tineapedis was the frequent site of involvement. Trichophytonmentagrophytes was the predominant species of dermatophytosis.
Conclusion: According to the obtained results on the prevalence rate of SCFIs between male and female patients in different age groups and also by taking into account the type of the prevalent fungi and the involvement site of the fungal infection, it is possible to take appropriate action for prevention and treatment of these kind of diseases by using important keys of the results to research etiological and underlying factors involved in these diseases.

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Tinea versicolor (TV) is a common superficial fungal infection of the skin, characterized by scaling and mild disturbance of the skinpigmentation. It typically affects the chest, upper back, and shoulders. However, the involvement of more unusual regions of the body such as the face and scalp, arms and legs, genitalia, groin and palms and soles has been reported. This report is a case of groin TV caused by Malassezia furfur affecting a 25-year-old man in Iran. After sampling, direct smears with 15% Potassium hydroxide (KOH) and staining with methylene blue were prepared. In direct microscopic examination, budding yeast cells with typical scar and short curved mycelium were observed. To identifying the strains of M. furfur, differential tests and culture on Sabouraud dextrose agar and mDixon agar media were performed. The clinician must be aware of these variations in the location of TV and perform an appropriate diagnostic workup when lesions have the mor­phological characteristics of TV despite an unusual location.

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Background: Adverse effects of synthetic pigments used in pharmaceutical andfoodindustriesand etc,have created a tendency toward the application of natural pigments. Environmental conditions are important factors in the growth and physiological function of different organisms. The aim of this study was to evaluate the growth rate of fungal biomass and production rate of black pigment (melanin) in fungus Exophialacrusticola under different incubation time, temperature, and light conditions to obtain an optimal condition for their production.
Materials and Methods: After obtaining an optimal incubation temperature, cultured fungus in potato dextrose agar and broth media was exposed to blue, yellow, white, red, green, and darknesslight conditions with 14-35 daysof incubation times. The averageamount of produceddry weight of fungal biomass and pigmentweremeasured, and the results were statistically analyzed with SPSS software ver.22.
Results:Suitable incubation temperature for fungal growthwas 22°C.The maximum average amount of fungal biomass (0.17 g)and pigment production (OD = 0.94) were after 35 days of incubation (p< .05) and under yellow light (0.135 g) (OD= 0.98), respectively (p< .05).
Conclusion: By optimization the incubation time, temperature, and light for the growth and production of pigmentinfungusE.crusticola, it is possible to produce a large amount of fungus and its related pigmentin order to be utilized in a variety of industrialand pharmaceutical use, and etc. Also, due to the fungus rapid growth in response to the yellow light, it is possible to use this feature in isolation and early diagnosis of this fungusin suspected pathogenesiscases.

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Background:Survival of dermatophytesinskin scales and nail scraps sampled from human lesions could have ecological and epidemiologicalimportance.The aim of this study was to store humanskin scale and nail lesions infected with dermatophyteagents,at -20°C for a long timeand to investigate the re-isolation rate of dermatophytes species from such samples after storage.
Materials and Methods:After referral to Medical Mycology Laboratory of Tehran University of Medical Science, the patients were subjected to sampling. Confirmation of dermatophytepositive result in direct smears was done with Potassium hydroxide, then culturing on Sabouraud dextrose agar media was performed, and species were identifiedusing standard procedures, and remaining samples were stored at -20°C. After 10 years, samples were re-examined for the presence and re-isolation of intended fungi according to the standard procedures.
Results:From a total of 5 species enrolled in this study, Epidermophyton floccosum, Trichophyton mentagrophytes, andTricholosporumviolaceum survived, andTrichophyton rubrum andTrichophytonverrucosumlost their viability at -20°C after 10 years. There was a significant difference between the re-isolation rate and the type of dermatophytes (p<.05). E. floccosum had the highest re-isolation rate (66.7%), followed by T. mentagrophytes (27%). All of the re-isolated dermatophytes were taken from scales samples, but none from nailscraps samples.
Conclusion: Some dermatophytes species including E. floccosum are able to maintain their ability to survive for a long time in human scale samples in certain time and temperature conditions (10 years at -20 °C) and to grow in appropriate conditions. These findings should be considered in ecological and epidemiological studies.

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Aims: In imbalanced conditions, Candida species colonization as a normal microflora of human skin and some mucosal surfaces is replaced by invasive forms (budding yeast cells, pseudohyphae, and true hyphae). This study aimed to investigate the frequency of Candida species and candidiasis with emphasis on the presence and propensity of different Candida species for pseudohyphae and true hyphae formation  in clinical samples taken from various clinical forms of candidiasis.
Materials & Methods: In this cross-sectional study (2018 to 2019), sampling was done from 492  patients suspected to candidiasis, referred to the Medical Mycology Laboratory. Employing direct microscopy and culturing methods, the Candida species were identified using morphological and biochemical characteristics and also PCR-RFLP and DNA sequencing.
Findings: From a total of 96 candidiasis patients, 44.9% were identified with superficial-cutaneous and 55.1% with visceral candidiasis. The most clinical strains were isolated from fingernail scrapings (33.2%), followed by bronchoalveolar lavage samples (17%). The mycelium was found in 55.2% of the cases, and the highest frequency was related to the nail specimens (34%, p <.05). C. albicans was the predominant species forming mycelium (69.8%), followed by C. tropicalis, but no mycelium was found in C. guilliermondii cases. Mycelium formation was observed more in patients with an underlying disease such as AIDS and organ transplantation (p <.05).
Conclusion: Non-albicans Candida species have also the propensity to induce an invasive form of mycelial in the skin and to increase internal organs temperature, exacerbating clinical symptoms. This finding is important for choosing proper antifungal treatments and should be taken into account by clinicians.

 

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Backgrounds: A novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has now spread to all countries of the world, including Iran. Although anti-SARS-CoV-2 antibodies may be identified in patients using immunological methods with sufficient sensitivity and specificity, the conclusive diagnosis of the disease is made using the molecular RT-PCR method. A population-based seroepidemiological survey was conducted to quantify the proportion of the exposed population with SARS-CoV-2 antibodies and evaluate whether the antibodies are a marker of total or partial immunity compared to the population that remains susceptible to the virus.
Material & Methods: This cross-sectional study was conducted to investigate the seroprevalence of COVID-19 in Valiasr, Sajad, and Ghaem hospitals in Tehran, the capital of Iran, from April to the end of October 2020. Clotted and heparinized blood specimens (2mL) were collected from the patients. The serum and plasma were separated and stored at −80 °C until use. Anti-SARS-CoV-2 IgG and IgM antibodies were examined in the serum samples of 1375 in-patients admitted to the hospitals using ELISA kits. The obtained data were analyzed using SPSS software Ver.22.0 by employing statistical tests such as Chi-square and Fisher’s exact tests. A p-value <.05 was considered as significant.
Findings: In total, 1375 participants were enrolled in this study, and SARS‐CoV‐2 antibodies were detected in 291 patients using IgM‐IgG antibody assay. Among the seropositive patients studied, 187 were male (64.3%), and 104 were female (35.7%) (p<.05). The mean age of the patients was 49±8.4 years; the majority of whom (27%) were in the age group of 31-40 years. Also, the lowest frequency of infected cases was related to the age group of 1-10 years (p <.05). The seroprevalence of SARS‐CoV‐2 IgM or IgG antibodies was determined to be 21.2%. Diabetes mellitus was the most common underlying disease among SARS‐CoV‐2 patients [p=.05; Odd Ratio=1.61(0.90-2.91)].
Conclusion: The use of conventional serological assays, such as the enzyme-linked immunoassay (ELISA), for detecting specific IgM and IgG antibodies in SARS‐CoV‐2 patients has a high-throughput advantage while minimizing false-negative results obtained using the RT-PCR method. In this study, the seroprevalence of SARS-CoV-2 antibodies was determined to be 21%. Control of diabetes, among other influential factors, plays an important role in the management and control of COVID-19.

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In this work, using finite element method (FEM) the effects of preload factor on the dynamic stability of noncircular two lobe hydrodynamic micropolar lubricated journal bearing based on the linear and nonlinear analytical dynamic models are presented. Assuming that the rotor is solid, the governing Reynolds equations for incompressible lubrication of journal bearing have been modified using micropolar theory. Later, the linear and nonlinear dynamic models, including a certain harmonic disturbances and time dependent trajectory of rotor center are applied to obtain the stability performance of bearing. The 4th order Rung-Kutta method has been used to solve the time dependent equations of rotor motion. Finally, the numerical results for the critical mass parameter and whirl frequency ratio of rotor as the stability characteristics of bearing are evaluated for different values of preload factor and compared together. Results show that the stability performance of two lobe bearing enhances by increasing the amount of bearing noncircularity in terms of the critical mass parameter increase and decrease of the whirl frequency ratio. Also, by comparing two dynamic analysis methods, it is obvious that the results of linear dynamic model are more cautious in different investigated cases. The results of nonlinear dynamic analysis reveal that by increasing the value of preload factor the dynamic response of rotor center involves return to steady state equilibrium position, limit cycle periodic motions and contact between rotor and bearing's shell.

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In first part of this study the methods of direct and indirect entering the effect of induced velocity in blade element theory to achieve lift force in hover flight of Drosophila flapping insect are investigated. Then a new algorithm for Induced velocity correction based on Rankin-Froude jet theory and direct method is presented. The results of previous and new methods to aerodynamic simulation of this insect in hovering flight with combined flapping and pitching angles were compared with published experimental results. The results of this comparison indicate that one of the models based on the indirect method as the best way to predict the experimental results. In second part of this work, the sensitivity of the instantaneous and mean force, produced by insect modeled wing, is examined with change in six wing important motion parameters. This parameters Includes: flapping frequency, phase difference between flapping and pitching angle, flapping and pitching amplitudes and flapping and pitching variations with respect to time in flapping cycle. The results show that with increasing frequency and flapping amplitude lift increasingly increases. Also, range of phase difference percent between flapping and pitching angle that lead to maximum lift of the wings is introduced. Results also show that with tending variation of flapping angle in cycle to sinusoidal trend, the lift force increases.

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The use of biological agents, also known as biological weapons in modern terms, to eliminate enemies and rivals, has been a critical issue in recent decades. The history of political developments in Iran during the Islamic Middle Ages has been witness to many instances of using weaponized biological agents for accomplishing political-military goals. This research employs a historical approach and attempts to identify the functions of biological agents in political and military developments of Iran during the Islamic Middle Ages. The results indicate that in addition to functioning as an instance of deterring propaganda, thus breaking the enemy's morale, biological weapons were able to alter the balance of military power in the battleground and determine the triumphs and defeats. Accordingly, biological agents have had other military and political implications, such as sabotaging enemies' weaponry and equipment and eliminating prominent figures. Iran's history has documented innumerable instances of such applications of biological weapons during the Middle Ages.