Noise Levels Associated With New York City's Mass Transit Systems

Objectives. We measured noise levels associated with various forms of mass transit and compared them to exposure guidelines designed to protect against noise-induced hearing loss.Methods. We used noise dosimetry to measure time-integrated noise levels in a representative sample of New York City mass transit systems (subways, buses, ferries, tramway, and commuter railways) aboard transit vehicles and at vehicle boarding platforms or terminals during June and July 2007.Results. Of the transit types evaluated, subway cars and platforms had the highest associated equivalent continuous average (L_eq) and maximum noise levels. All transit types had L_eq levels appreciably above 70 A-weighted decibels, the threshold at which noise-induced hearing loss is considered possible.Conclusions. Mass transit noise exposure has the potential to exceed limits recommended by the World Health Organization and the US Environmental Protection Agency and thus cause noise-induced hearing loss among riders of all forms of mass transit given sufficient exposure durations. Environmental noise–control efforts in mass transit and, in cases in which controls are infeasible, the use of personal hearing protection would benefit the ridership''s hearing health.For the first time in history, more than half of the world''s population lives in cities, and it is projected that more than two thirds of the population will live in cities by 2030.¹ An important factor supporting the growth and viability of urban centers is mass transportation, which is rapidly expanding to keep pace with increasing demand. For example, in 2004 there were 95 subway systems worldwide; today there are 167, a 76% increase in only 5 years.² Although there are well-documented environmental and public health benefits associated with mass transit, interest in the health and safety effects of mass transit on urban communities is increasing.^3–5 A particular concern is the potential for mass transit to result in excessive exposure to noise.Noise exposure is a function of 2 main factors: (1) the frequency-weighted exposure level, measured in A-weighted decibels (dBA), and (2) the exposure duration. The causal association between chronic exposure to excessive noise and permanent, irreversible, noise-induced hearing loss (NIHL) is well known, as are the adverse social, psychological, and occupational effects associated with the condition. Nonauditory adverse health effects have also been reported,^6–8 and recent research suggests that excessive noise exposure may be linked to hypertension and ischemic heart disease, disruptions in stress hormones, and sleep disorders.^9–12There are no comprehensive national or international surveillance programs for hearing loss. Worldwide, more than 250 million people are estimated to suffer from hearing loss, of which at least 30 million cases represent NIHL.¹³ In the United States alone, between 3 to 10 million people are estimated to have NIHL.¹⁴ Hearing loss from all causes ranks among the top 10 most common serious health problems worldwide, and NIHL is the leading occupational disease in industrialized nations.^14,15 The limited data available suggest not only that NIHL prevalence and incidence rates are extraordinarily high but also that the associated costs are enormous.^16,17 Importantly, even though US occupational exposure regulations have been in place for decades, rates of NIHL-related workers'' compensation cases remain high. Therefore, nonoccupational sources of exposure are coming under scrutiny, including mass transit.The size of the population exposed to mass transit noise is of considerable magnitude. The US mass transit network, with an infrastructure encompassing subways, buses, commuter and light rail, ferry boats, trolleys, and tramways, is the largest in the world, with 9.7 billion passenger rides in 2006.¹⁸ There are 14 subway systems in the United States, with a combined daily ridership in excess of 10 million people.^19–21 Five of the US systems are more than 75 years old, and the largest, the New York City subway system, with over 4 million riders per weekday,²² is more than 100 years old. These older systems were designed before noise-control technologies were available. Worldwide, there are 2 subway systems with even greater ridership rates: Tokyo''s is the largest at 2.6 billion passenger rides per year, and Moscow''s is the second largest with 2.5 billion.^23,24In a recent sound-level pilot survey on subways,³ we noted levels that potentially exceeded the community exposure limits initially recommended by the US Environmental Protection Agency (EPA) in 1974 and confirmed by the World Health Organization (WHO) in 1998. WHO and EPA recommended daily allowable exposure times are 24 hours at 70 dBA, 8 hours at 75 dBA, 2.7 hours at 80 dBA, 0.9 hours at 85 dBA, and 0.3 hours at 90 dBA. Chronic exposures that exceed these allowable combinations of duration and noise level are expected to produce NIHL in some members of the exposed population.^25,26The amount of NIHL anticipated to result from specific noise-exposure levels can be predicted with a model published by the International Organization for Standardization.²⁷ This model allows users to estimate the amount of NIHL expected to result from chronic 8-hour equivalent continuous average (L_eq) noise exposures between 75 and 100 dBA or 24-hour L_eq exposures between 70 and 95 dBA. The model permits the estimation of median values of expected NIHL as well as values for the 0.05 to 0.95 fractiles among an exposed population for given exposure levels and durations. Based on the WHO and EPA recommendations, chronic exposure to 80.3 dBA for more than 160 minutes per day may be expected to produce hearing loss in some exposed individuals, and a 90.2-dBA level likewise may cause hearing loss with just 18 minutes of exposure per day.Few data involving dosimetry measurements of noise exposures associated with mass transit have been reported previously. In a study of the daily noise exposures experienced by 32 people in Madrid, Spain, Diaz et al.²⁸ measured noise levels associated with a variety of self-reported transportation exposures with noise dosimeters. Zheng et al.²⁹ conducted 24-hour noise dosimetry on 221 residents of Beijing, China, and assessed the noise levels associated with self-reported activities, including commuting. Nearly all other studies that have evaluated noise levels associated with subway equipment are decades old and based on sound level measurements rather than dosimetry. In 1931, Stanton conducted an unpublished noise-level survey of the New York City subways,³⁰ and in 1971, Harris and Aitken³¹ reported levels measured on specific New York City train line platforms and cars. A small sound level survey on a subway system in India was also recently reported.³²Our current study expanded on our pilot study of subway noise and assessed average noise levels on a variety of types of mass transit to further evaluate noise exposure among transit riders.     

In vitro dermal absorption of methyl salicylate, ethyl parathion, and malathion: first responder safety

In vitro tests with fresh dermatomed (0.3 to 0.4 mm thick) female breast skin and one leg skin specimen were conducted in Bronaugh flow-through Teflon diffusion cells with three chemicals used to simulate chemical warfare agents: 14C-radiolabeled methyl salicylate (MES), ethyl parathion (PT), and malathion (MT), at three dose levels (2, 20, and 200 mM). Tests were conducted at a skin temperature of 29 degrees C using a brief 30-min exposure to the chemical and a 6.5-h receivor collection period. Rapid absorption of all three chemicals was observed, with MES absorbed about 10-fold faster than PT and MT. For MES, PT, and MT, respectively, there was 32%, 7%, and 12% absorption into the receivor solution (Hank's HEPES buffered saline with 4% bovine serum albumin [BSA], pH 7.4) at the low dose (2 mM), 17%, 2%, and 3% at the medium dose (20 mM), and 11%, 1%, and 1% at the high dose (200 mM) levels. Including the skin depot for MES, PT, and MT, respectively, there was 40%, 41%, and 21% (low dose), 26%, 16%, and 8% (medium dose), and 13%, 19%, and 10% (high does) absorption. Efficacy of skin soap washing conducted at the 30 min exposure time ranged from 31% to 86%, varying by chemical and dose level. Skin depot levels were highest for the relatively lipophilic PT. "Pseudo" skin permeability coefficient (K(p)) data declined with dose level, suggesting skin saturation had occurred. An in-depth comparison with literature data was conducted and risk assessment of first responder exposure was briefly considered.     

Evaluation of coexistence of the Human Herpesvirus type 8 (HHV‐8) infection and pemphigus

Background Human Herpesvirus type 8 (HHV‐8) is a new member of the herpes virus family, first found in the tissue of acquired immune deficiency syndrome (AIDS)‐related Kaposi’s sarcoma. Environmental factors including viral infection may play a role in the onset and/or development of pemphigus. Some studies based on polymerase chain reaction findings suggest an association between HHV‐8 and pemphigus. The aim of this study is investigation of the association of pemphigus with HHV‐8 and the relationship between inflammatory and acantholytic cells with HHV‐8 infection. Methods Tissue‐extracted DNA from 41 paraffin‐embedded skin tissues from patients first presenting with pemphigus was tested using nested PCR for the presence of HHV‐8. A total of 37 cases had pemphigus vulgaris (PV) and 4 patients had pemphigus foliaceus (PF). For our control group, normal skin of 21 cosmetic surgery patients were included. Furthermore, microscopic slides with H&E staining were evaluated for the number of inflammatory and acantholytic cells per microscopic field. Results Skin lesions from 13 of 37 patients (35.1%) with PV and 2 of 4 cases (50%) with PF were positive for HHV‐8 DNA. All specimens in our control group were negative for this virus. Conclusion HHV‐8 infection might be a contributing factor in the initiation or development of pemphigus.     

Neutrophil activation and neutrophil extracellular traps (NETs) in COVID-19 ARDS and immunothrombosis

Acute respiratory distress syndrome (ARDS) is an acute inflammatory condition with a dramatic increase in incidence since the beginning of the coronavirus disease 19 (COVID-19) pandemic. Neutrophils play a vital role in the immunopathology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by triggering the formation of neutrophil extracellular traps (NETs), producing cytokines including interleukin-8 (CXCL8), and mediating the recruitment of other immune cells to regulate processes such as acute and chronic inflammation, which can lead to ARDS. CXCL8 is involved in the recruitment, activation, and degranulation of neutrophils, and therefore contributes to inflammation amplification and severity of disease. Furthermore, activation of neutrophils also supports a prothrombotic phenotype, which may explain the development of immunothrombosis observed in COVID-19 ARDS. This review aims to describe hyperinflammatory ARDS due to SARS-CoV-2 infection. In addition, we address the critical role of polymorphonuclear neutrophils, inflammatory cytokines, and the potential targeting of CXCL8 in treating the hyperinflammatory ARDS population.     

Resistance to new chemical insecticides in the house fly, Musca domestica L., from dairies in Punjab, Pakistan

The house fly, Musca domestica L., is one of the major pests in dairy operations that has developed resistance to a number of insecticides with different modes of action. Adult house fly populations from six dairies in Punjab, Pakistan were evaluated for resistance to insecticides with novel modes of action (abamectin, emamectin benzoate, fipronil, imidacloprid, indoxacarb, and spinosad). Significant levels of resistance to most of the insecticides tested were observed in the present study. For avermectins at LC₅₀ level, the resistance ratios were in the range of 38.40 to 94.44-fold for abamectin and 13.16 to 36.30-fold for emamectin benzoate. Fipronil LC₅₀ resistance ratios exceeded 10-fold in three house fly populations, while all the populations had >10-fold resistance ratios for imidacloprid. Indoxacarb and spinosad had the lowest resistance ratios that ranged from 3.02 to 7.12-fold for indoxacarb and 2.91 to 9.0-fold for spinosad. As the resistance to fipronil, indoxacarb, and spinosad are emerging, therefore these chemicals should be used cautiously in management programs to retain the efficacy for longer times.     

Survivin as a diagnostic and therapeutic marker for thyroid cancer

Thyroid cancer (TC) is known as the most prevalent form of endocrine malignancy. With regard to high heterogeneity of the nodules, problem of discriminating between benign and malignant ones in terms of pathological characteristics, as well as lack of appropriate molecular markers; significant efforts are being made to identify molecular markers that able to detect tumorous lesions. Survivin, the newest member of the family of proteins inhibiting cell apoptosis, has been recently considered as a novel molecule marker for cancer. Studies on TC have also demonstrated distinctive expression of survivin and its splice variants in cancer cells compared to normal ones. Therefore, detection of survivin expression and its new splice variants can be utilized to identify tumor nodules and distinguish them from non-cancerous ones, along with other routine laboratory methods.