Portable ultrasonic humidifier exacerbates indoor bioaerosol risks by raising bacterial concentrations and fueling pathogenic genera

Indoor Air ◽  
2021 ◽  
Author(s):  
Zili Yang ◽  
Lu‐An Chen ◽  
Chuanjun Yang ◽  
Yuqian Gu ◽  
Rong Cao ◽  
...  
Keyword(s):  
Ultrasonic Humidifier ◽  
Bacterial Concentrations

209. Historic Airborne Fungal and Bacterial Concentrations in the New York City Region

2001 ◽  
Author(s):  
J. Springston ◽  
W. Esposito ◽  
C. Yang
Keyword(s):  
New York ◽  
New York City ◽  
York City ◽  
City Region ◽  
Bacterial Concentrations

Experimental Measurement of Turbulent Diffusion, Initial Dilution and T90

1986 ◽  
Vol 18 (11) ◽  
pp. 131-140
Author(s):  
Edmundo Garcia Agudo ◽  
Jose Leomax dos Santos
Keyword(s):  
Experimental Measurement ◽  
Tracer Technique ◽  
Initial Dilution ◽  
Coastal Cities ◽  
Actual Solution ◽  
The World ◽  
Visual Aid ◽  
Proper Design ◽  
Key Aspects ◽  
Bacterial Concentrations

The final disposal of sewage using submarine outfalls has become an actual solution for coastal cities all over the world. In order to get the best results it is necessary to carry out specific studies for the proper design of the outfall. Dilution and decrease in bacterial concentrations are two key aspects for the design. Radioisotope tracers have been used extensively in studies performed in some Brazilian waterbodies where outfall systems exist or are to be installed. As far as dilution measurement is concerned, both point and continuous radiotracer injections can provide useful results. The T90 measurements can be better accomplished using a combined tracer technique for sampling the sewage field, using the radiotracer for dilution measurement and rhodamine B as a visual aid. Typical results of dilution measurement using both techniques mentioned, as well as a summary of T 90 results obtained for the Santos, Fortaleza and Maceió outfalls are presented.

scholarly journals Development and Evaluation of an Ultrasonic Humidifier to Control Humidity in a Cold Storage Room for Postharvest Quality Management of Dates

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 949
Author(s):  
Maged Mohammed ◽  
Nashi Alqahtani ◽  
Hamadttu El-Shafie
Keyword(s):  
Quality Management ◽  
Cold Storage ◽  
Cooling System ◽  
Positive Impact ◽  
Droplet Diameter ◽  
Postharvest Quality ◽  
Main Element ◽  
Small Scale ◽  
Storage Room ◽  
Ultrasonic Humidifier

Dates are subjected to postharvest losses in quality and quantity caused by water loss, fermentation, insect infestation, and microbial spoilage during storage. Cold storage is the main element in the postharvest quality management used for fruit preservation. Although cold storage is used for dates, precision control of the relative humidity (RH) using ultrasonic applications is not used thus far, or it is applied to other fruits on a small scale. Therefore, we designed and constructed an ultrasonic humidifier (DUH) for RH control in the cold storage room (CSR) of dates. The optimum air velocity of 3 m s−1 at the outlets of the DUH ducts produced a mist amount of 6.8 kg h-1 with an average droplet diameter of 4.26 ± 1.43 µm at the applied voltage of 48 V and frequency of 2600 kHz of the transducers. The experimental validation was carried out by comparing a CSR controlled with the DUH with two conventional CSRs. The three tested CSRs were similar in dimensions, cooling system, and amount of stored dates. The time required for cooling 800 kg of dates in the controlled CSR from 25 °C to the target temperature of 5 °C was approximately 48 h. The DUH precisely controlled the RH at the maximum RH set point of 80% in the tested CSR at 5 °C. The controlled RH at 80% has a positive impact on the physicochemical characteristics of the stored dates. It significantly reduced the weight loss of the fruits and preserved fruit mass, moisture content, water activity, firmness, and color parameters. However, no significant effect was observed on fruit dimensions, sphericity, and aspect ratio. The microbial loads of mesophilic aerobic bacteria, molds, and yeasts fell within the acceptable limits in all tested CSRs. Both stored date fruits and artificially infested dates showed no signs of insect activity in the controlled CSR at the temperature of 5 °C and RH of 80%. The DUH proved to be a promising technology for postharvest quality management for dates during cold storage.

Effects of Inorganic and Organic Fertilization on Physicochemical Parameters, Bacterial Concentrations, and Shrimp Growth inLitopenaeus vannameiCultures with Zero Water Exchange

2013 ◽  
Vol 44 (4) ◽  
pp. 499-510 ◽  
Author(s):  
Guillermo F. Lara-Anguiano ◽  
Héctor M. Esparza-Leal ◽  
Juan C. Sainz-Hernández ◽  
Jesús T. Ponce-Palafox ◽  
Wenceslao Valenzuela-Quiñónez ◽  
...  
Keyword(s):  
Physicochemical Parameters ◽  
Water Exchange ◽  
Organic Fertilization ◽  
Bacterial Concentrations ◽  
Inorganic And Organic

Simple fabrication of a three-dimensional porous polymer film as a diffuser for organic light emitting diodes

Nanoscale ◽  
2014 ◽  
Vol 6 (23) ◽  
pp. 14446-14452 ◽  
Author(s):  
Byung Wan Lim ◽  
Min Chul Suh
Keyword(s):  
Polymer Film ◽  
Spin Coating ◽  
Three Dimensional ◽  
Cost Effective ◽  
Porous Polymer ◽  
Organic Light Emitting Diodes ◽  
Coating Process ◽  
Light Emitting ◽  
Organic Light ◽  
Ultrasonic Humidifier

We have investigated a simple and cost-effective fabrication method for a porous polymer film employing the spin-coating process during continuous supply of water droplets by an ultrasonic humidifier.

scholarly journals Acanthamoeba-Campylobacter Coculture as a Novel Method for Enrichment of Campylobacter Species

2007 ◽  
Vol 73 (21) ◽  
pp. 6864-6869 ◽  
Author(s):  
Diana Axelsson-Olsson ◽  
Patrik Ellstr�m ◽  
Jonas Waldenstr�m ◽  
Paul D. Haemig ◽  
Lars Brudin ◽  
...  
Keyword(s):  
Culture Medium ◽  
Bacterial Species ◽  
Oxygen Quenching ◽  
Free Living ◽  
Promising Tool ◽  
Low Concentrations ◽  
Novel Method ◽  
Selective Antibiotics ◽  
Different Sources ◽  
Bacterial Concentrations

ABSTRACT In this study, we present a novel method to isolate and enrich low concentrations of Campylobacter pathogens. This method, Acanthamoeba-Campylobacter coculture (ACC), is based on the intracellular survival and multiplication of Campylobacter species in the free-living protozoan Acanthamoeba polyphaga. Four of the Campylobacter species relevant to humans and livestock, Campylobacter jejuni, C. coli, C. lari, and C. hyointestinalis, were effectively enriched by the coculture method, with growth rates comparable to those observed in other Campylobacter enrichment media. Studying six strains of C. jejuni isolated from different sources, we found that all of the strains could be enriched from an inoculum of fewer than 10 bacteria. The sensitivity of the ACC method was not negatively affected by the use of Campylobacter-selective antibiotics in the culture medium, but these were effective in suppressing the growth of seven different bacterial species added at a concentration of 104 CFU/ml of each species as deliberate contamination. The ACC method has advantages over other enrichment methods as it is not dependent on a microaerobic milieu and does not require the use of blood or other oxygen-quenching agents. Our study found the ACC method to be a promising tool for the enrichment of Campylobacter species, particularly from water samples with low bacterial concentrations.

The distribution and abundance of viruses in the Southern Ocean during spring

2000 ◽  
Vol 12 (4) ◽  
pp. 414-417 ◽  
Author(s):  
Harvey Marchant ◽  
Andrew Davidson ◽  
Simon Wright ◽  
John Glazebrook
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Surface Waters ◽  
Significant Relationship ◽  
Polar Front ◽  
Open Ocean ◽  
Bacterial Concentration ◽  
Viral Abundance ◽  
Chroococcoid Cyanobacteria ◽  
Bacterial Concentrations

The concentrations of viruses, bacteria, chroococcoid cyanobacteria and chlorophyll a were determined in surface waters of the Southern Ocean during spring. Viral concentrations declined southward from around 4 × 106 ml−1 near Tasmania to a minimum of around 1 × 106 ml−1 at the Polar Front. South of the Front, virus concentrations increased again, reaching around 4 × 106 ml−1 in the sea-ice zone south of 60°S. Bacterial concentration decreased southwards across the Southern Ocean from around 6.5 × 105 ml−1 near Tasmania to < 1.0 × 105 ml−1 in the sea-ice zone. Cyanobacteria accounted for < 8% of the prokaryotes. There was no significant relationship between viral abundance and eithercyanobacterial or chl a concentration. Viral and bacterial concentrations were not significantly correlated north (P {0.10 < r < 0.20}) or south (P {0.20 < r < 0.5}) of the Polar Front. The virus to bacteria ratio (VBR) was between 3 and 15 in the open ocean but varied between 15 and 40 in the sea-ice region. These virus concentrations and VBRs indicate that viruses are no less important in Southern Ocean ecosystems than elsewhere in the world's oceans.

scholarly journals Stable neutralization of virulent bacteria using temperate phage in the mammalian gut

2019 ◽  
Author(s):  
Bryan B. Hsu ◽  
Jeffrey C. Way ◽  
Pamela A. Silver
Keyword(s):  
Temperate Phage ◽  
Cascading Effects ◽  
E Coli ◽  
Bacterial Action ◽  
Exogenous Genes ◽  
Selection For ◽  
Mouse Model Of Infection ◽  
Bacterial Concentrations ◽  
New Framework ◽  
Lambdoid Phages

ABSTRACTElimination or alteration of select members of the gut microbiota is key to therapeutic efficacy. However, the complexity of these microbial inhabitants makes it challenging to precisely target bacteria without unexpected cascading effects. Here, we use bacteriophage to deliver exogenous genes to specific bacteria by genomic integration of temperate phage for long-lasting modification. As a real-world therapeutic test, we engineered λ phage to transcriptionally-repress shigatoxin by using genetic hybrids between λ and other lambdoid phages to overcome resistance encoded by the virulent prophage derived from enterohemorrhagic E. coli. We show that a single dose of engineered phage propagates throughout the bacterial community and reduces shigatoxin production in an enteric mouse model of infection without markedly affecting bacterial concentrations. We thus minimize the selection for resistance by relying on anti-virulence and not anti-bacterial action. Our work reveals a new framework for transferring functions to bacteria within their native environment.

scholarly journals Bacillus cereus NVH 0500/00 Can Adhere to Mucin but Cannot Produce Enterotoxins during Gastrointestinal Simulation

2015 ◽  
Vol 82 (1) ◽  
pp. 289-296 ◽  
Author(s):  
Varvara Tsilia ◽  
Frederiek-Maarten Kerckhof ◽  
Andreja Rajkovic ◽  
Marc Heyndrickx ◽  
Tom Van de Wiele
Keyword(s):  
Bacillus Cereus ◽  
Food Poisoning ◽  
Intestinal Bacteria ◽  
Low Ph ◽  
Final Concentration ◽  
Adhesion Assay ◽  
Content Type ◽  
The Stability ◽  
Bacterial Concentrations

ABSTRACTAdhesion to the intestinal epithelium could constitute an essential mechanism ofBacillus cereuspathogenesis. However, the enterocytes are protected by mucus, a secretion composed mainly of mucin glycoproteins. These may serve as nutrients and sites of adhesion for intestinal bacteria. In this study, the food poisoning bacteriumB. cereusNVH 0500/00 was exposedin vitroto gastrointestinal hurdles prior to evaluation of its attachment to mucin microcosms and its ability to produce nonhemolytic enterotoxin (Nhe). The persistence of mucin-adherentB. cereusafter simulated gut emptying was determined using a mucin adhesion assay. The stability of Nhe toward bile and pancreatin (intestinal components) in the presence of mucin agar was also investigated.B. cereuscould grow and simultaneously adhere to mucin duringin vitroileal incubation, despite the adverse effect of prior exposure to a low pH or intestinal components. The final concentration ofB. cereusin the simulated lumen at 8 h of incubation was 6.62 ± 0.87 log CFU ml−1. At that point, the percentage of adhesion was approximately 6%. No enterotoxin was detected in the ileum, due to either insufficient bacterial concentrations or Nhe degradation. Nevertheless, mucin appears to retainB. cereusand to supply it to the small intestine after simulated gut emptying. Additionally, mucin may play a role in the protection of enterotoxins from degradation by intestinal components.

Biomass Retention in Advanced Anaerobic Reactors

1990 ◽  
Vol 22 (1-2) ◽  
pp. 17-24 ◽  
Author(s):  
G. Albagnac
Keyword(s):  
Current Knowledge ◽  
Point Of View ◽  
High Rate ◽  
Efficient Treatment ◽  
Anaerobic Reactors ◽  
Start Up ◽  
Biomass Retention ◽  
Rate Processes ◽  
Bacterial Aggregates ◽  
Bacterial Concentrations

Recognition of the advantages of anaerobic wastewater treatment induced the development of high rate processes, i.e. reactors designed to allow an efficient treatment of even diluted streams. The performance of these advanced reactors is mainly dependent on the retention within the reactor of high bacterial concentrations. The prevailing mechanism is either the formation of bacterial aggregates with good settling characteristics, the development of methanogenic biolayers at the surface of inert carriers or both. During the past decade information on the biology of methanogenic ecosystems became available at an increasing rate. From a practical point of view it can be stated that the biological conversion of organic compounds to methane is reasonably well understood. However the current knowledge on the aggregation and adhesion of methanogenic consortia remains very limited. In most cases reactor start-up procedures are rather long and appear to be more empirical than rational. This paper is a brief presentation on the current knowledge of methanogenic aggregates and biofilms. The fundamental aspects of bacterial adhesion and the modelling of anaerobic biofilms growth are presented elsewhere.

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