Effect of voicing and articulation manner on aerosol particle emission during human speech.

Previously, we demonstrated a strong correlation between the amplitude of human speech and the emission rate of micron-scale expiratory aerosol particles, which are believed to play a role in respiratory disease transmission. To further those findings, here we systematically investigate the effect of different 'phones' (the basic sound units of speech) on the emission of particles from the human respiratory tract during speech. We measured the respiratory particle emission rates of 56 healthy human volunteers voicing specific phones, both in isolation and in the context of a standard spoken text. We found that certain phones are associated with significantly higher particle production; for example, the vowel /i/ ("need," "sea") produces more particles than /ɑ/ ("saw," "hot") or /u/ ("blue," "mood"), while disyllabic words including voiced plosive consonants (e.g., /d/, /b/, /g/) yield more particles than words with voiceless fricatives (e.g., /s/, /h/, /f/). These trends for discrete phones and words were corroborated by the time-resolved particle emission rates as volunteers read aloud from a standard text passage that incorporates a broad range of the phones present in spoken English. Our measurements showed that particle emission rates were positively correlated with the vowel content of a phrase; conversely, particle emission decreased during phrases with a high fraction of voiceless fricatives. Our particle emission data is broadly consistent with prior measurements of the egressive airflow rate associated with the vocalization of various phones that differ in voicing and articulation. These results suggest that airborne transmission of respiratory pathogens via speech aerosol particles could be modulated by specific phonetic characteristics of the language spoken by a given human population, along with other, more frequently considered epidemiological variables

A literature review on beneficial role of vitamins and trace elements: evidence from published clinical studies

COVID-19 is a kind of SARS-CoV-2 viral infectious pneumonia. This research aims to perform a bibliometric analysis of the published studies of vitamins and trace elements in the Scopus database with a special focus on COVID-19 disease. To achieve the goal of the study, network and density visualizations were used to introduce an overall picture of the published literature. Following the bibliometric analysis, we discuss the potential benefits of vitamins and trace elements on immune system function and COVID-19, supporting the discussion with evidence from published clinical studies. The previous studies show that D and A vitamins demonstrated a higher potential benefit, while Selenium, Copper, and Zinc were found to have favorable effects on immune modulation in viral respiratory infections among trace elements. The principles of nutrition from the findings of this research could be useful in preventing and treating COVID-19

Global prevalence of nosocomial infection: A systematic review and meta-analysis

Objectives: Hospital-acquired infections (HAIs) are significant problems as public health issues which need attention. Such infections are significant problems for society and healthcare organizations. This study aimed to carry out a systematic review and a meta-analysis to analyze the prevalence of HAIs globally.   Methods: We conducted a comprehensive search of electronic databases including EMBASE, Scopus, PubMed and Web of Science between 2000 and June 2021. We found 7031 articles. After removing the duplicates, 5430 studies were screened based on the titles/abstracts. Then, we systematically evaluated the full texts of the 1909 remaining studies and selected 400 records with 29,159,630 participants for meta-analysis. Random-effects model was used for the analysis, and heterogeneity analysis and publication bias test were conducted.   Results: The rate of universal HAIs was 0.14 percent. The rate of HAIs is increasing by 0.06 percent annually. The highest rate of HAIs was in the AFR, while the lowest prevalence were in AMR and WPR. Besides, AFR prevalence in central Africa is higher than in other parts of the world by 0.27 (95% CI, 0.22-0.34). Besides, E. coli infected patients more than other micro-organisms such as Coagulase-negative staphylococci, Staphylococcus spp. and Pseudomonas aeruginosa. In hospital wards, Transplant, and Neonatal wards and ICU had the highest rates. The prevalence of HAIs was higher in men than in women.   Conclusion: We identified several essential details about the rate of HAIs in various parts of the world. The HAIs rate and the most common micro-organism were different in various contexts. However, several essential gaps were also identified. The study findings can help hospital managers and health policy makers identify the reason for HAIs and apply effective control programs to implement different plans to reduce the HAIs rate and the financial costs of such infections and save resources

Airborne Infectious Disease Transmission Via Expiratory Aerosol Particles and Aerosolized Fomites

Epidemics of infectious disease such as influenza and tuberculosis cause hundreds of thousands of deaths worldwide annually. This annual death rate can increase to millions with sporadic, unpredictable pandemics, such as the 1918 flu pandemic or potentially the ongoing COVID-19 pandemic. The main routes of infectious disease transmission among humans have long been a matter of debate. Transmission may occur via (i) “direct” physical contact with infected individual, (ii) “indirect” contact with contaminated surfaces (i.e. fomites), such as a contaminated door knob, (iii) sprays of virus-laden respiratory droplets, such as from a cough or sneeze, impacting immediately onto the respiratory mucosa of a susceptible individual, or (iv) by the eventual inhalation of the smaller residual solid cores of evaporated respiratory droplets (i.e. aerosol particles) emitted during breathing, talking, coughing, and sneezing. Controversy remains regarding the relative contribution of these different modes (contact, droplet, or aerosol) in transmitting specific respiratory diseases. For example, documented cases of COVID-19 transmission by asymptomatic and presymptomatic individuals, who do not cough or sneeze to any appreciable extent, suggests that aerosol transmission plays an important role, but little is known about aerosol particle production by asymptomatic individuals. This dissertation has two broad themes. First, we focus on aerosol particle emission during human expiratory activities. We show that the rate of particle emission during normal human speech is positively correlated with the loudness (amplitude) of vocalization regardless of the language spoken (English, Spanish, Mandarin, or Arabic), and that a small fraction of individuals behaves as “speech superemitters,” consistently releasing an order of magnitude more particles than their peers. We further investigate the effect of voicing and articulation manner on aerosol emission during human speech, and demonstrate that particle emission rates are positively correlated with the vowel content of a phrase; conversely, particle emission decreases during phrases with a high fraction of voiceless fricatives such as /f/. Next, we tested the efficacy of medical-grade and homemade masks in controlling aerosol particle emission from expiratory activities. We find that surgical and KN95 masks reduce the particle emission rates by 90% and 74% on average during speaking and coughing, respectively, compared to wearing no mask. However, the efficacy of homemade cloth and paper masks is confounded by shedding of non-expiratory micron-scale particulates from friable cellulosic fibers present in homemade masks. These results highlight the importance of regular changing of disposable masks and washing of homemade re-usable masks. The preceding results focused on generation of aerosol particles during human expiratory activities. In the second part of this dissertation, we next consider how aerosol particles can spread through the air in indoor environments. We begin with a theoretical model, using a point source and turbulent diffusivity model valid in the limit of low Stokes numbers. We calculate transmission probabilities versus position and exposure time for different values of the turbulent Péclet number, and we demonstrate that under some certain circumstances speaking can lead to higher probabilities of transmission than coughing. We then turn our attention to experimental animal models of human influenza, performed in collaboration with colleagues at the Icahn School of Medicine at Mt. Sinai. We provide evidence of a mode of transmission seldom considered for infectious disease: airborne virus transport on microscopic particles called “aerosolized fomites.” We show that the airborne particulates produced by infected guinea pigs are mainly non-respiratory in origin by quantitatively characterizing the particles emitted from cages containing guinea pigs using both an Interferometric Mie Imaging system and an Aerodynamic Particle Sizer. Our results surprisingly show that an uninfected, virus-immune animal whose body is contaminated with influenza virus can transmit the virus through the air to a susceptible partner in a separate cage. We further demonstrate that aerosolized fomites can be generated from inanimate objects, such as by manually rubbing a paper tissue contaminated with influenza virus. Our results suggest that besides respiratory droplets and aerosols, aerosolized fomites may contribute to influenza virus transmission in animal models of human influenza, if not among humans themselves, with important but understudied implications for public health. This dissertation concludes with a discussion of potential avenues for future work in the field of airborne infectious disease transmission

Producing Shape-Engineered Alginate Particles Using Viscoplastic Fluids

Journal article on particle engineering with non-Newtonian fluids to form a wide range of particle morphologies.</p

Dust Source Identification in the Middle East by Using Remote Sensing

A dust storm is a common phenomenon in many parts of the world, especially in arid and semiarid regions of the world. Dust storm adverse effects on the agriculture production and gardening, pollution of water and soil resources, a variety of respiratory diseases and the finally on the environmental issues, social challenges, a sharp reduction in horizontal visibility and road accidents. In this research, dust source identification in the Middle East with using MODIS satellite images was used in the period of time 2004-2014. For dust source identification 4 indices BTD3132، BTD2931، NDDI and D for 45 MODIS satellite images were calculated. Then with make a false-color combination (FCC) determined the best of a method dust source identification. The results showed that color combination BTD2931 ، B4 and B3 determined the best color combination for enhancement dust and dust source identification. The results showed that 212 points dust source identified in the case study that 123 points were in Iran and 93 Points in out of the country. The results also show that after Iran, Afghanistan has highest points dust source in the study area. The Middle East arid and semi-arid climates and precipitation in this area rarely exceed 300 mm per year As a result; this area has been poor vegetation cover and precipitation hardening and is susceptible to erosion

The study of the frequency of dyes used in food products delivered at Fasa restaurants using Thin Layer Chromatography and spectrophotometric methods in 1397

Background & Objective: Today, in order to maintain or improve the appearance, composition, flavor and nutritional value for food, compounds called additive are added, that they lead to complications in the human body, which the colors are only one of these substances. The aim of this study was to determine the frequency of consuming colors in saffron foods in Fasa in 1397 by thin layer chromatography and spectrophotometry methods. Materials & Methods: This is a type of Experimental study that was conducted by a cross-sectional study in Fasa. A total of 64 samples of food were collected from restaurants and after color extraction with Hydrochloric acid and purification, the color analysis was performed using thin-layer chromatography and spectrophotometry. The Data were analyzed using Excel software. Results: Out of 64 samples, 36 samples (56.2%) of natural color and 28 samples (43.8%) of artificial color were used. Of this amount, artificial color (57.1%) was non‐permitted artificial color (16 samples) and 42.9% of permitted artificial color (12 samples). Also, 75% of the natural colors used were saffron type. Conclusion: Considering the high level of artificial colors found in the samples of this study, preventive measures are essential because the high consumption of non-edible and edible color in foods and their adverse effects on health, raising the level of awareness of manufacturers and consumers about the complications, the amount of consumption or lack of use of these substances is necessary