UV-LED fluence determination by numerical method for microbial inactivation studies

In this study, a computational method is proposed to calculate irradiance and fluence rate based on the LED’s relative radiation profile and its radiant power, which are two standard pieces of information available in an LED’s datasheet. UV-LED was modeled as a polychromatic point source with a specific radiation profile and the fluence rate was calculated by solving the Radiative Transfer Equation by considering the refraction, reflection, and absorption of the medium. The irradiance and fluence rate predictions on the surface of the water were evaluated successfully by radiometry and actinometry measurements, respectively. The fluence rate imposed by 265-nm UV-LED and 275-nm UV-LED in Petri dishes with internal diameters of 5 cm and 9 cm were measured using biodosimetry with E. coli and MS2, when the UV-LED germicidal factor was obtained by considering the LED emission spectrum and the microorganism action spectra. Biodosimetry experiments using E. coli and MS2 at exposure times over 200 seconds indicated a close agreement between the simulation and experimental data. Such results are indicating the kinetic rate constants of a microorganism can be estimated without performing kinetic study using the action spectrum of microorganisms. Further, the results showed the proposed method can be applied for fluence rate determination for any LED’s radiation profile, LED position, and the experimental apparatus’s regardless of the availability o...
Source: Journal of Photochemistry and Photobiology A: Chemistry - Category: Chemistry Source Type: research

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Conclusion: Our results advance the current mechanistic understanding of the pseurotin-induced inhibition of IgE production in B-cells by linking the effect to STAT signaling, and associated modulation of B-cell proliferation and differentiation. Together with our finding that structurally simpler pseurotin analogs were able to reproduce the effects of natural pseurotins, the presented work has implications for the future research on these secondary metabolites in the context of allergic diseases.Graphical abstact
Source: Phytomedicine - Category: Drugs & Pharmacology Source Type: research
Publication date: Available online 22 February 2020Source: Materials LettersAuthor(s): Li Chen, Hong Pan, Caifeng Zhuang, Mengyao Peng, Li ZhangAbstractTreatment against bacterial infection is of great significance for joint wound healing in medical nursing care. Thus, it is urgent to develop efficient antibacterial agent with excellent wound healing capability. In this research, a two-step strategy was employed for the development of novel chitosan scaffold reinforced by strontium doped TiO2 nanoparticles (CS/Sr-TiO2). The antibacterial activity of CS/Sr-TiO2 against Escherichia coli, and Staphylococcus aureus were evalua...
Source: Materials Letters - Category: Materials Science Source Type: research
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Source: Biotechnology Progress - Category: Biotechnology Authors: Tags: RESEARCH ARTICLE Source Type: research
Publication date: Available online 21 February 2020Source: Protein Expression and PurificationAuthor(s): Brett A. Beaupre, Joseph V. Roman, Graham R. MoranAbstractDihydropyrimidine dehydrogenase (DPD) catalyzes the reduction of uracil and thymine bases with electrons derived from NADPH. The mammalian DPD enzyme is a functional homodimer and has an elaborate cofactor arrangement. Two flavin cofactors (FAD and FMN) reside in two active site cavities that are separated by around 60 Å. The flavins are apparently bridged by four Fe4S4 clusters, two of which are provided by the partner protomer of the dimer. The study of...
Source: Protein Expression and Purification - Category: Biochemistry Source Type: research
This study demonstrated the electrospun fibrous mat with efficient on-demand antibacterial properties is promising for practical application in anti-infective therapy.Graphical abstract
Source: Chemical Engineering Journal - Category: Chemistry Source Type: research
In conclusion, our results suggested that AVNP2 could have an effect on the peri-tumor environment, obviously restraining the growth progress of gliomas, and eventually improving cognitive levels in C6-bearing rats.
Source: Brain, Behavior, and Immunity - Category: Neurology Source Type: research
ConclusionThe probability of virus detection is independent of the time between notification of the outbreak or symptom onset and sample collection. Our results suggest possible defects in cleaning protocols and disinfection in closed and semi-closed settings.
Source: Journal of Hospital Infection - Category: Infectious Diseases Source Type: research
Estimates of acute gastroenteritis (AGE) burden are difficult to compare between studies because of inconsistent definitions describing this illness. AGE definitions used in prospective, community-based childhood cohort studies were identified by searching databases for studies that collected daily observations of AGE symptoms. Disease definitions and refractory periods were extracted. Data from the Australian community-based Observational Research in Childhood Infectious Diseases birth cohort were used to calculate AGE incidence and duration using identified AGE definitions, and the World Health Organization definition fo...
Source: Journal of Pediatric Gastroenterology and Nutrition - Category: Gastroenterology Tags: Short Communications: Gastroenterology Source Type: research
We examined the nutritional composition and chemical resilience of fish roe skeins from the flying fish (Hirundichthys oxycephalus) that are commonly found in temperate and tropical oceans. The air-dried skeins contained 72-74% crude protein, high-quality protein composed of essential and most non-essential amino acids, and very low carbohydrate content. High macro and micro minerals, lipids, albeit at a low amount, composed of saturated and unsaturated fatty acids and water- and lipid-soluble vitamins were also present. The roe skeins were highly durable and resistant to nutrient decomposition through over-desiccation as ...
Source: Journal of Food Composition and Analysis - Category: Food Science Source Type: research
Conclusion: Escherichia coli, the predominant uropathogen, showed significant multidrug resistance to antibiotics commonly prescribed for the management of UTIs. These findings should form a basis for preliminary decision making on the appropriate line of treatment for UTIs.Escherichia coli isolates were highly susceptible to cefotaxime/clavulanic acid (100%) and nitrofurantoin (70%) but showed high resistance to cefuroxime (100%), ceftazidime (100%), nalidixic acid (90%), and ciprofloxacin (90%). PMID: 32076437 [PubMed]
Source: Interdisciplinary Perspectives on Infectious Diseases - Category: Infectious Diseases Tags: Interdiscip Perspect Infect Dis Source Type: research
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