scholarly journals An Ultraviolet C-Band LED device for disinfection of air, articles, and indoor environment

Author(s):  
Anwesh Sahu

<div> <div> <div> <p>Background: Commonly used items like wallets, keys, and phones are both tricky and impractical to disinfect from the dangers of harmful microbes. This study demonstrates the efficacy of UVC-LED technology in creating an efficient, useful, and practical solution.</p><p>Methods: As a demonstration of the efficacy of the UVC-LED light (275 nm), a panel of UVC LEDs was fabricated and was driven with a constant current electronic driver. Staphylococcus aureus and Escherichia coli were placed on Petri dishes, and placed 38 cm away from the UVC-LED panel. UVC flux measured at the petri dishes was 0.093 mW/cm2 . The method involved exposing both the bacteria to UVC treatment for 4 and 8 minutes. For each petri dish, the number of colony forming units were compared before and after the treatment and compared to the control.</p><p>Results: A significant reduction in colony forming unit (cfu) counts was found in all samples for both sets of bacteria: 97.9% in the 4 minutes treat- ment(22.3 mJ/cm2), and 99.9% in the 8 minutes treatment(44.6 mJ/cm2).</p><p>Conclusion: UVC-LED technology offers an effective, simple and inexpensive approach for disinfection. </p> </div> </div> </div>

2021 ◽  
Author(s):  
Anwesh Sahu

<div> <div> <div> <p>Background: Commonly used items like wallets, keys, and phones are both tricky and impractical to disinfect from the dangers of harmful microbes. This study demonstrates the efficacy of UVC-LED technology in creating an efficient, useful, and practical solution.</p><p>Methods: As a demonstration of the efficacy of the UVC-LED light (275 nm), a panel of UVC LEDs was fabricated and was driven with a constant current electronic driver. Staphylococcus aureus and Escherichia coli were placed on Petri dishes, and placed 38 cm away from the UVC-LED panel. UVC flux measured at the petri dishes was 0.093 mW/cm2 . The method involved exposing both the bacteria to UVC treatment for 4 and 8 minutes. For each petri dish, the number of colony forming units were compared before and after the treatment and compared to the control.</p><p>Results: A significant reduction in colony forming unit (cfu) counts was found in all samples for both sets of bacteria: 97.9% in the 4 minutes treat- ment(22.3 mJ/cm2), and 99.9% in the 8 minutes treatment(44.6 mJ/cm2).</p><p>Conclusion: UVC-LED technology offers an effective, simple and inexpensive approach for disinfection. </p> </div> </div> </div>


2013 ◽  
Vol 34 (5) ◽  
pp. 466-471 ◽  
Author(s):  
Deverick J. Anderson ◽  
Maria F. Gergen ◽  
Emily Smathers ◽  
Daniel J. Sexton ◽  
Luke F. Chen ◽  
...  

Objective.To determine the effectiveness of an automated ultraviolet-C (UV-C) emitter against vancomycin-resistant enterococci (VRE),Clostridium difficile, andAcinetobacterspp. in patient rooms.Design.Prospective cohort study.Setting.Two tertiary care hospitals.Participants.Convenience sample of 39 patient rooms from which a patient infected or colonized with 1 of the 3 targeted pathogens had been discharged.Intervention.Environmental sites were cultured before and after use of an automated UV-C-emitting device in targeted rooms but before standard terminal room disinfection by environmental services.Results.In total, 142 samples were obtained from 27 rooms of patients who were colonized or infected with VRE, 77 samples were obtained from 10 rooms of patients withC. difficileinfection, and 10 samples were obtained from 2 rooms of patients with infections due toAcinetobacter. Use of an automated UV-C-emitting device led to a significant decrease in the total number of colony-forming units (CFUs) of any type of organism (1.07 log10reduction;P< .0001), CFUs of target pathogens (1.35 log10reduction;P< .0001), VRE CFUs (1.68 log10reduction;P< .0001), and C.difficileCFUs (1.16 log10reduction;P< .0001). CFUs ofAcinetobacteralso decreased (1.71 log10reduction), but the trend was not statistically significantP= .25). CFUs were reduced at all 9 of the environmental sites tested. Reductions similarly occurred in direct and indirect line of sight.Conclusions.Our data confirm that automated UV-C-emitting devices can decrease the bioburden of important pathogens in real-world settings such as hospital rooms.


2020 ◽  
Vol 7 (1) ◽  
pp. 49-52
Author(s):  
Elisângela De Souza Loureiro ◽  
Luis Gustavo Amorim Pessoa ◽  
Thayla Christiane Putrick ◽  
Ariane De Andréa Pantaleão ◽  
Pamella Mingotti Dias

Compatibility studies are essential for the integration and simultaneous use of chemical and biological pest control methods since they are necessary for an Integrated Pest Management (IPM) program. In this work, the aim was to evaluate the compatibility of insecticides used in soybean and cotton crops for pest control with Bacillus thuringiensis (Bt). The in vitro inoculation technique was used with B. thuringiensis var. kurstaki and B. thuringiensis var. aizawai, in culture medium containing the following insecticides: beta-cyfluthrin (Bulldock®), methomyl (Bazuka®), thiamethoxam + lambda-cialotrina (Engeo Pleno®), zeta-cypermethrin (Fury 200®), acetamiprid (Saurus®), bifenthrin + carbosulfano (Talisman®) and bifenthrin (Talstar®), in Petri dishes. The Petri dishes were taken to the B.O.D. (Biological Oxygen Demand), at a temperature of 30 ± 1 ºC, 70 ± 10% RH (relative humidity) and a photophase of 12 h, for 24 hours. Colony growth was measured, and Colony Forming Units (CFU) counted in the total area of the Petri dish. The product that allowed growth to be significantly equal to or higher than the control was established as compatible, and the one that did not allow growth or was significantly less than the control was incompatible. It was found that all insecticides were classified as incompatible with the bioinsecticide.


Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 194
Author(s):  
Yung-Chih Wang ◽  
Yao-Hung Tsai ◽  
Ching-Fen Shen ◽  
Ming-Yao He ◽  
Yi-Chen Fu ◽  
...  

Escherichia coli has been known to cause a variety of infectious diseases. The conventional enzyme-linked immunosorbent assay (ELISA) is a well-known method widely used to diagnose a variety of infectious diseases. This method is expensive and requires considerable time and effort to conduct and complete multiple integral steps. We previously proposed the use of paper-based ELISA to rapidly detect the presence of E. coli. This approach has demonstrated utility for point-of-care (POC) urinary tract infection diagnoses. Paper-based ELISA, while advantageous, still requires the execution of several procedural steps. Here, we discuss the design and experimental implementation of a turntable paper-based device to simplify the paper-based ELISA protocols for the detection of E. coli. In this process, antibodies or reagents are preloaded onto zones of a paper-based device and allowed to dry before use. We successfully used this device to detect E. coli with a detection limit of 105 colony-forming units (colony-forming unit [CFU])/mL.


Author(s):  
Giuseppina Di Martino ◽  
Salvatore Pasqua ◽  
Bruno Douradinha ◽  
Francesco Monaco ◽  
Chiara Di Bartolo ◽  
...  

To evaluate and validate the efficacy of disinfectants used in our cleaning procedure, in order to reduce pharmaceutical hospital surfaces’ contaminations, we tested the action of three commercial disinfectants on small representative samples of the surfaces present in our hospital cleanrooms. These samples (or coupons) were contaminated with selected microorganisms for the validation of the disinfectants. The coupons were sampled before and after disinfection and the microbial load was assessed to calculate the Log10 reduction index. Subsequently, we developed and validated a disinfection procedure on real surfaces inside the cleanrooms intentionally contaminated with microorganisms, using approximately 107–108 total colony forming units per coupon. Our results showed a bactericidal, fungicidal, and sporicidal efficacy coherent to the acceptance criteria suggested by United States Pharmacopeia 35 <1072>. The correct implementation of our cleaning and disinfection procedure, respecting stipulated concentrations and contact times, led to a reduction of at least 6 Log10 for all microorganisms used. The proposed disinfection procedure reduced the pharmaceutical hospital surfaces’ contaminations, limited the propagation of microorganisms in points adjacent to the disinfected area, and ensured high disinfection and safety levels for operators, patients, and treated surfaces.


Author(s):  
Surinder Kaur M. S. Pada ◽  
Poh Lishi ◽  
Kim Sim Ng ◽  
Sarathamani Rethenam ◽  
Lilibeth Silagan Alenton ◽  
...  

Abstract Background Computerisation of various processes in hospitals and reliance on electronic devices raises the concern of contamination of these devices from the patient environment. We undertook this study to determine if an attached hand hygiene device that unlocks the screen of a computer on wheels (COW) on usage can be effective in decreasing the microbiological burden on computer keyboards. Methods An electronic hand sanitizer was integrated onto the COW. A prospective cohort study with a crossover design involving 2 control and 2 intervention wards was used. The study end point was the number of colony forming units found on the keyboards. Bacteria were classified into 4 main groups; pathogenic, skin flora, from the environment or those thought to be commensals in healthy individuals. We then used a mixed effects model for the statistical analysis to determine if there were any differences before and after the intervention. Results Thirty-nine keyboards were swabbed at baseline, day 7 and 14, with 234 keyboards cultured, colony forming units (CFUs) counted and organisms isolated. By mixed model analysis, the difference of mean bacteria count between intervention and control for week 1 was 32.74 (− 32.74, CI − 94.29 to 28.75, p = 0.29), for week 2 by 155.86 (− 155.86, CI − 227.45 to − 83.53, p < 0.0001), and after the 2-week period by 157.04 (− 157.04, CI − 231.53 to − 82.67, p < 0.0001). In the sub-analysis, there were significant differences of pathogenic bacteria counts for the Intervention as compared to the Control in contrast with commensal counts. Conclusion A hand hygiene device attached to a COW may be effective in decreasing the microbiological burden on computer keyboards.


1995 ◽  
Vol 20 (1) ◽  
pp. 329-329
Author(s):  
E. Guerrero-Rodriguez ◽  
S. Davalos-Luna ◽  
J. Corrales-Reynaga

Abstract Populations of MCR of commercial field corn from Arenal, Jalisco were exposed to nine insecticides of organophosphorous (OP), cabamate, organo chlorinated and pyrethroid groups. Larvae were collected from the roots of corn plants daily, and confined in polyethylene black bags of two kg capacity with humidity and germinated corn as food for larvae. Insects were taken to the laboratory of Sanidad Vegetal in Guadalajara, Jalisco. Dilutions of the insecticides tested were prepared using acetone from 500 to 5000 ppm (6 to 9 dosage/product). For this study 20 larvae of last instar were selected and 1 u, liter of the solution was placed topically on the thorax, after this, each larva was placed in a petri dish with a moistened paper towel and the petri dishes confined in a cardboard box to eliminate light. Mortality counts were carried out at 24 hours. Percent mortality was corrected by Abbott’s formula. The mortality data were analyzed by probit to obtain LC50 and LC,5 values for each insecticide.


2020 ◽  
Vol 10 (2) ◽  
pp. 335-346
Author(s):  
Arnold Landry Fotseu Kouam ◽  
Gideon Aghaindum Ajeagah

Abstract The aim of this study is to determine the effectiveness of disinfectant on the viability of eggs from three nematode species (Ascaris, Trichuris, Ankylostoma). It was conducted in a microcosm from June 2018 to June 2019. The wastewater scan was sampled using 5 L sterile containers, the sample was arranged in four replicas, three tests and one control. The test samples received three disinfectants (Moringa, calcium hypochlorite and Moringa associated with calcium hypochlorite) at varying concentrations. The physical and chemical parameters were measured before and after the application of each disinfectant. The samples were then observed under an optical microscope. The viability of the eggs was determined by incubating the Petri dish samples at 30 °C for 30 days. The analyses show that some physicochemical parameters can significantly influence the efficacy of disinfectant on the eggs. The calcium hypochlorite associated with Moringa at 0.6 g/L showed greater efficacy on reducing viability and inactivation of eggs with 100% efficacy yield rates on Ankylostoma and Trichuris trichiuria and 97% on Ascaris lumbricoides eggs; this efficacy is significantly different from that observed on samples treated with Moringa and simple calcium hypochlorite. Of the three parasites tested, A. lumbricoides showed greater resistance to the disinfectant.


2018 ◽  
Vol 29 (5) ◽  
pp. 459-464 ◽  
Author(s):  
Larissa Tais Soligo ◽  
Ediléia Lodi ◽  
Ana Paula Farina ◽  
Matheus Albino Souza ◽  
Cristina de Mattos Pimenta Vidal ◽  
...  

Abstract The aim of this study was to compare the efficacy of grape seed extract (GSE), calcium hypochlorite [Ca(ClO)2], and sodium hypochlorite (NaOCl) irrigant solutions with rotary or reciprocating instrumentation for disinfection of root canals inoculated with Enterococcus faecalis. The mesiobuccal root canals of mandibular molars were prepared and inoculated with Enterococcus faecalis for 21 days. The roots were then randomly divided into the following eight experimental groups (n=11) according to the instrumentation technique and disinfection protocol: ProTaper Next or Reciproc R25 with sodium chloride (control group), 6% NaOCl, 6% Ca(ClO)2, or 50% GSE used for irrigation during instrumentation. The antimicrobial activity was determined on the basis of a reduction in colony-forming units (CFUs) counted on bacterial samples collected before and after root canal instrumentation and expressed as a percentage of reduction. Data were evaluated by two-way ANOVA followed by Tukey HSD post-hoc tests (p<0.05). No significant differences were observed in bacterial reduction between the ProTaper Next and Reciproc R25 systems (p>0.05), regardless of the irrigant solution used. Furthermore, all active solutions (6% NaOCl, 50% GSE, and 6% Ca(ClO)2) showed similar potential to reduce bacterial counts (p>0.05) and were significantly more effective than sodium chloride (control) (p<0.05). The results suggest that the GSE and Ca(ClO)2 have potential clinical application as irrigant solutions in endodontic therapy since they present bactericidal efficacy against Enterococcus faecalis.


1998 ◽  
Vol 23 (1) ◽  
pp. 372-372
Author(s):  
Nihat Demirel ◽  
Whitney Cranshaw

Abstract Trials were conducted with adult, field collected migratory grasshoppers to determine susceptibility to ingestion expo sure to Beauveria bassiana Strain GHA (BotaniGard WP), spinosad (Conserve SC) a garlic-derived insecticide/repellent (Garlic Barrier), neem oil (Tril ogy) and a neem extract (BioNeem). Field collected late instar grasshoppers were confined, 8 per petri dish (100 mm X 15 mm), with 6 petri dishes usetl per treatment. Treatments involved dipping alfalfa leaves into the insecticide solutions and allowing them to air dry before feeding these to the grasshop pers. After the originally treated foliage were consumed, untreated foliage was used to maintain grasshoppers in all treatments. Mortality was assessed a 24, 48, 96, and 192 h after exposure.


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