VOC

VOC
  • 文章类型: Journal Article
    自2020年12月以来,公共卫生机构实施了各种疫苗接种策略,以遏制SARS-CoV-2的传播,以及现有的非药物干预措施(NPI)。最初的策略侧重于为老年人接种疫苗,以防止住院和死亡,但是随着疫苗的普及,确定最佳策略以安全解除NPI,同时避免病毒死灰复燃变得很重要。
    我们扩展了经典的确定性SIR隔室疾病传播模型,以模拟不同疫苗推出场景下NPI的提升。使用多伦多的病例和疫苗接种数据,加拿大在2020年12月28日至2021年5月19日期间,我们估计了NPI升级/放松的过去阶段的传播,以比较在不同日期取消NPI对病例的影响。住院治疗,和死亡,根据20岁年龄组不同程度的疫苗覆盖率,解释免疫力下降的原因。
    我们发现,一旦老年人的覆盖率足够高(至少一次剂量为80%),目标的主要年龄组是20-39岁和40-59岁,其中,如果要在夏季取消NPI,则到2021年6月中旬需要至少70%的第一剂覆盖率,以最大程度地减少死灰复燃的可能性。虽然NPI取消的每一种情况都有复苏,我们还发现,在乐观的疫苗接种覆盖率下(到6月中旬70%的覆盖率,以及将2021年8月的重新开放推迟到2021年9月)可以在2021年12月31日之前将病例数和严重结果减少约57%。
    我们的结果表明,将疫苗接种策略集中在工作年龄人群上可以遏制SARS-CoV-2的传播。然而,即使成年人的疫苗接种覆盖率很高,增加接触和放松个人保护性行为是不可取的,因为预计会出现复苏,尤其是早些时候重新开放。
    Since December 2020, public health agencies have implemented a variety of vaccination strategies to curb the spread of SARS-CoV-2, along with pre-existing Nonpharmaceutical Interventions (NPIs). Initial strategies focused on vaccinating the elderly to prevent hospitalizations and deaths, but with vaccines becoming available to the broader population, it became important to determine the optimal strategy to enable the safe lifting of NPIs while avoiding virus resurgence.
    We extended the classic deterministic SIR compartmental disease-transmission model to simulate the lifting of NPIs under different vaccine rollout scenarios. Using case and vaccination data from Toronto, Canada between December 28, 2020, and May 19, 2021, we estimated transmission throughout past stages of NPI escalation/relaxation to compare the impact of lifting NPIs on different dates on cases, hospitalizations, and deaths, given varying degrees of vaccine coverages by 20-year age groups, accounting for waning immunity.
    We found that, once coverage among the elderly is high enough (80% with at least one dose), the main age groups to target are 20-39 and 40-59 years, wherein first-dose coverage of at least 70% by mid-June 2021 is needed to minimize the possibility of resurgence if NPIs are to be lifted in the summer. While a resurgence was observed for every scenario of NPI lifting, we also found that under an optimistic vaccination coverage (70% coverage by mid-June, along with postponing reopening from August 2021 to September 2021) can reduce case counts and severe outcomes by roughly 57% by December 31, 2021.
    Our results suggest that focusing the vaccination strategy on the working-age population can curb the spread of SARS-CoV-2. However, even with high vaccination coverage in adults, increasing contacts and easing protective personal behaviours is not advisable since a resurgence is expected to occur, especially with an earlier reopening.
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  • 文章类型: Letter
    要确定最佳隔离持续时间,我们评估了107例严重急性呼吸综合征冠状病毒2Omicron变异型病例患者密切接触者从暴露到诊断的时间.从暴露到诊断的平均时间为3.7天;70%的诊断在第5天进行,99.1%在第10天进行,建议隔离10天。
    To determine optimal quarantine duration, we evaluated time from exposure to diagnosis for 107 close contacts of severe acute respiratory syndrome coronavirus 2 Omicron variant case-patients. Average time from exposure to diagnosis was 3.7 days; 70% of diagnoses were made on day 5 and 99.1% by day 10, suggesting 10-day quarantine.
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  • 文章类型: Journal Article
    本研究依赖于阿维利诺COVID-19大流行期间的空气质量评估,描述了过去几年和连续几年,在这种情况下,意大利最糟糕的城市之一。这份手稿的主要目的是调查检疫和封锁措施对空气污染的影响。主要大气污染物的浓度(一氧化碳(CO),臭氧(O3),细颗粒物(PM2.5和PM10),在2020年1月至12月期间,使用区域环境保护局(ARPAC)的两个固定监测站(AV1和AV2)记录了苯(C6H6)和二氧化氮(NO2)。在封锁期间(2020年3月9日至5月18日),结果表明,仅CO水平显着降低,苯和NO2,而对于PM10,AV1超过8次,AV2超过13次。结果表明,就PM水平而言,交通对Avellino空气质量的影响并不占主导地位,因此有必要对改善空气质量的重要且不可扩展的决策进行认真反思。
    The present study relies on the air quality evaluation during COVID-19 pandemic in Avellino, described in the last years and for several consecutive years, among the worst Italian cities in this context. The main purpose of this manuscript was to investigate the effects of quarantine and lockdown measures on air pollution. The concentrations of the main atmospheric pollutants (Carbon monoxide (CO), Ozone (O3), Fine Particulate (PM2.5 and PM10), Benzene (C6H6) and Nitrogen dioxide (NO2) were recorded during the period January-December 2020 using two stationary monitoring stations (AV1 and AV2) of the Regional Environmental Protection Agency (ARPAC). During the lockdown period (March 9-May 18, 2020), results indicated significant reductions only in the levels of CO, benzene and NO2, while for PM10 the limit of 50 μg m-3 was passed 8 times for AV1 and 13 times for AV2. The results showed the not predominant role of traffic on air quality in Avellino regards to PM levels and make it necessary a serious reflection about important and not extendable decisions to improve the air quality.
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  • 文章类型: Journal Article
    Plant beneficial rhizobacteria may antagonize soilborne plant pathogens by producing a vast array of volatile organic compounds (VOCs). The production of these compounds depends on the medium composition used for bacterial cell growth. Accordingly, Lysobacter capsici AZ78 (AZ78) grown on a protein-rich medium was previously found to emit volatile pyrazines with toxic activity against soilborne phypathogenic fungi and oomycetes. However, the discrepancy between the quantity of pyrazines in the gaseous phase and the minimum quantity needed to achieve inhibition of plant pathogens observed, lead us to further investigate the volatile-mediated inhibitory activity of AZ78. Here, we show that, besides VOCs, AZ78 cells produce ammonia in increased amounts when a protein-rich medium is used for bacterial growth. The production of this volatile compound caused the alkalinization of the physically separated culture medium where Rhizoctonia solani was inoculated subsequently. Results achieved in this work clearly demonstrate that VOC, ammonia and the growth medium alkalinization contribute to the overall inhibitory activity of AZ78 against R. solani. Thus, our findings suggest that the volatile-mediated inhibitory activity of rhizobacteria in protein-rich substrates can be regarded as a result of multiple factors interaction, rather than exclusively VOCs production.
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  • 文章类型: Journal Article
    Improved indoor air quality (IAQ) is one of the critical components of green building design. Green building tax credit (e.g., New York State Green Building Tax Credit (GBTC)) and certification programs (e.g., Leadership in Energy & Environmental Design (LEED)) require indoor air quality measures and compliance with allowable maximum concentrations of common indoor air pollutants. It is not yet entirely clear whether compliance with these programs results in improved IAQ and ultimately human health. As a case in point, annual indoor air quality measurements were conducted in a residential green high-rise building for five consecutive years by an industrial hygiene contractor to comply with the building\'s GBTC requirements. The implementation of green design measures resulted in better IAQ compared to data in references of conventional homes for some parameters, but could not be confirmed for others. Relative humidity and carbon dioxide were satisfactory according to existing standards. Formaldehyde levels during four out of five years were below the most recent proposed exposure limits found in the literature. To some degree, particulate matter (PM) levels were lower than that in studies from conventional residential buildings. Concentrations of Volatile Organic Compounds (VOCs) with known permissible exposure limits were below levels known to cause chronic health effects, but their concentrations were inconclusive regarding cancer health effects due to relatively high detection limits. Although measured indoor air parameters met all IAQ maximum allowable concentrations in GBTC and applicable LEED requirements at the time of sampling, we argue that these measurements were not sufficient to assess IAQ comprehensively because more sensitive sampling/analytical methods for PM and VOCs are needed; in addition, there is a need for a formal process to ensure rigor and adequacy of sampling and analysis methods. Also, we suggest that a comprehensive IAQ assessment should include mixed mode thermal comfort models, semi-volatile organic compounds, assessment of new chemicals, and permissible exposure levels of many known indoor VOCs and bioaerosols. Plus, the relationship between energy consumption and IAQ, and tenant education on health effects of indoor pollutants and their sources may need more attention in IAQ investigations in green buildings.
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