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1.
Build Environ ; 92: 756-763, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32288032

RESUMO

Increasing a ceiling fan's speed from its lowest setting of 61 rpm, which resulted in 0.77 m3/s of airflow, to its highest setting of 176 rpm, which resulted in 2.5 m3/s of airflow, or having the fan blow either upward or downward had no statistically significant effect on the efficacy of upper-room ultraviolet germicidal irradiation (UVGI). This outcome suggests that air circulation due to the ceiling fan was sufficient and that any additional increase would not improve efficacy. Numerous experimental studies on upper-room UVGI in which fans were used to provide air mixing have been published. However, none have quantified the air movement produced by these fans or described their tests in sufficient detail to allow results to be compared to predictions using computational fluid dynamics (CFD). The present work provides the required information. In addition to the usual boundary conditions needed for CFD, we made experimental measurements of UV susceptibility of the microorganisms used in the upper-room UVGI tests. We measured UV susceptibilities for Mycobacterium parafortuitum and Bacillus atrophaeus spores to be 0.074 and 0.018 m2/J, respectively. In a previous publication, we reported the spatial distribution of fluence rate, which is also needed for predicting efficacy from CFD. In a companion paper referred to as Part II, upper-room UVGI efficacy was predicted by both Eulerian and Lagrangian CFD and compared to the experimental results from the present study.

2.
Indoor Air ; 24(2): 116-24, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23889191

RESUMO

A novel whole ceiling upper-room ultraviolet germicidal irradiation (UVGI) system [eggcrate ultraviolet (UV)] has been developed that incorporates open-cell 'eggcrate'-suspended ceiling panels and bare UV lamps with a ceiling fan. Upper-room UVGI is more effective for air disinfection than mechanical ventilation at much lower installation and operating costs. Conventional upper-room UVGI fixtures employ multiple tightly spaced horizontal louvers to confine UV to the upper-room. These louvered fixtures protect occupants in the lower-room from UV-induced eye and skin irritation, but at a major cost to fixture efficiency. Using a lamp and ballast from a conventional upper-room UVGI fixture in the eggcrate UV system, the germicidal efficacy was markedly improved even though the UV radiation emitted by the lamp was unchanged. This fundamental change in the application of upper-room UVGI air disinfection should permit wider, more effective application of UVGI globally to reduce the spread of airborne infection.


Assuntos
Microbiologia do Ar , Desinfecção/instrumentação , Ambiente Controlado , Raios Ultravioleta
3.
Indoor Air ; 19(5): 433-41, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19689447

RESUMO

As a first step in conducting studies of airborne influenza transmission, we compared the collection performance of an SKC Biosampler, a compact cascade impactor (CCI), Teflon filters, and gelatin filters by collecting aerosolized influenza virus in a one-pass aerosol chamber. Influenza virus infectivity was determined using a fluorescent focus assay and influenza virus nucleic acid (originating from viable and non-viable viruses) was measured using quantitative PCR. The results showed that the SKC Biosampler recovered and preserved influenza virus infectivity much better than the other samplers - the CCI, Teflon, and gelatin filters recovered only 7-22% of infectious viruses compared with the Biosampler. Total virus collection was not significantly different among the SKC Biosampler, the gelatin, and Teflon filters, but was significantly lower in the CCI. Results from this study show that a new sampler is needed for virus aerosol sampling, as commercially available samplers do not efficiently collect and conserve virus infectivity. Applications for a new sampler include studies of airborne disease transmission and bioterrorism monitoring. Design parameters for a new sampler include high collection efficiency for fine particles and liquid sampling media to preserve infectivity. Practical Implications New air samplers are needed to study infectious airborne viruses and learn about airborne disease transmission. As a first step in designing a new air sampler to collect influenza virus we evaluated four commercial samplers and determined necessary design parameters for a new collector.


Assuntos
Microbiologia do Ar , Orthomyxoviridae/isolamento & purificação , Virologia/instrumentação , Aerossóis , Animais , Sequência de Bases , Linhagem Celular , Efeito Citopatogênico Viral , DNA Viral/genética , Cães , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H1N1/patogenicidade , Influenza Humana/transmissão , Orthomyxoviridae/genética , Orthomyxoviridae/patogenicidade , RNA Viral/genética , RNA Viral/isolamento & purificação
4.
J Occup Med ; 35(1): 57-60, 1993 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8423505

RESUMO

Adverse effects of antineoplastic drug exposure have been well documented in therapeutically treated patients and proposed as a potential hazard for occupationally exposed populations. Concern stems from accrued evidence of mutagenicity, carcinogenicity, and teratogenicity of many of these drugs. While the clinical significance of occupational exposure is controversial, OSHA issued handling guidelines for these agents in 1986, principally suggesting usage of a vertical laminar airflow biological safety cabinet and good work practices. Industrial hygiene measures of workplace antineoplastic exposure have been few and are limited to air sampling, addressing only the inhalation exposure route. We report here air and surface cyclophosphamide sampling results in a hospital oncology pharmacy and outpatient clinic where OSHA guidelines are in place. Results reveal rare air samples with detectable cyclophosphamide, but multiple surface wipe samples with measurable cyclophosphamide concentrations. Occupational health personnel, therefore, must consider work practices as determinants of surface contamination and recognize the potential importance of dermal and ingestion routes of exposure.


Assuntos
Ciclofosfamida , Exposição Ocupacional , Recursos Humanos em Hospital , Serviço de Farmácia Hospitalar , Poluentes Ocupacionais do Ar/análise , Ciclofosfamida/análise , Humanos , Recursos Humanos de Enfermagem Hospitalar , Ambulatório Hospitalar , Farmacêuticos
5.
Gastroenterology ; 72(3): 434-9, 1977 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-319036

RESUMO

Previous studies have shown in a qualitative manner that endotoxin can cross gut epithelium, but precise quantitation has not been possible. The present studies were undertaken to measure quantitatively the mucosal to serosal unidirectional flux of endotoxin with the use of an in vitro rat gut sac preparation. 51Cr-Labeled endotoxin was placed in the mucosal bath in concentrations ranging from 0.05 to 2.0 mg per ml. Over a 2-hr period of time, a small amount of endotoxin was transported transmurally, which was shown chromatographically to be similar to the starting material and which retained its toxic and immunogenic properties. It was first shown that the presence of 2.0 mg per ml of endotoxin in the mucosal bath did not significantly alter the tissue's histology or permeability to 3-O-methyl-D-glucose. When unidirectional fluxes were measured, it was found that the flux was not proportional to the endotoxin concentration as would be expected with a passively permeable solute, but rather its transport system became "saturated," displaying a maximum transport rate of 4.72 (mug per cm) per 2 hr and a Km of 0.425 mg per ml. The isolated gut sac provides an excellent model for the precise study of factors involved in endotoxin absorption.


Assuntos
Endotoxinas/metabolismo , Absorção Intestinal , Animais , Relação Dose-Resposta a Droga , Escherichia coli , Feminino , Mucosa Intestinal/metabolismo , Cinética , Modelos Biológicos , Ratos , Membrana Serosa/metabolismo
8.
Proc Soc Exp Biol Med ; 149(3): 766-70, 1975 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1096167

RESUMO

Cholestyramine (Dowex 1-X2), a strongly basic anion-exchange resin, has previously been shown to bind bacterial endotoxin, preventing both its toxicity and intestinal absorption. Because hemoperfusion through charged and uncharged resins is practical, a study was undertaken to test the endotoxin-binding characteristics of a number of resins. The resin to be tested was washed and swelled overnight, and 1 mg/ml of 51Cr-labeled endotoxin was added and the mixture, agitated and incubated at 37 degrees for a specific time period. In the Dowex 1 series, the 1-X2 was superior to the 1-X4 and 1-X8 in its ability to bind E. coli endotoxin, removing about 90% from solution in 15 min. Increasing mesh size seemed to offer more binding sites for each Dowex 1 resin. Activated charcoal adsorbed about 90% of the endotoxin also, but Amberlite XAD-2 showed little binding capacity. Injection of filtrate from unlabeled E. coli and S. typhosa resin-treated solution into rats, demonstrated that both Dowex 1-X2 and activated charcoal prevented the transaminase rise noted in animals injected with solutions not so treated. It is concluded that Dowex 1-X2 resin and activated charcoal efficiently remove endotoxin in vitro, and may offer a unique method for removing circulating endotoxin in vivo.


Assuntos
Endotoxinas , Resinas Sintéticas , Alanina Transaminase/sangue , Animais , Aspartato Aminotransferases/sangue , Carvão Vegetal/análise , Endotoxinas/análise , Escherichia coli , Feminino , Lipopolissacarídeos , Conformação Molecular , Peso Molecular , Polissacarídeos Bacterianos , Ratos , Resinas Sintéticas/farmacologia , Salmonella typhi , Fatores de Tempo
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