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IntroductionAlthough numerous studies have estimated the inhalation dose of metals emitted from electronic cigarettes (e-cigs), the impact of factors including aerosol size and the atomising power of e-cig aerosols on estimating the inhalation dose of metals remains underexplored. A comprehensive understanding of these determinants is essential to assess the health risks associated with inhaling e-cig aerosols, which may contain potentially harmful metals.ObjectivesThe aim of this study is to elucidate the mass and inhalation doses of potentially harmful metals in e-cig aerosols by different particle size and their association with the various atomising powers of e-cig devices and flavours.MethodsSize-segregated e-cig aerosols were generated and collected in a exposure chamber, using an 11-stage cascade impactor for the analyses of aerosol mass and metals. The metal deposition dose in the human respiratory tract was calculated using a mathematical respiratory deposition estimation model and metal mass concentration by the size of aerosols.ResultsIn this study, the results showed that neither an increase in atomising power (from 5 to 20 W) nor e-cig flavours resulted in a significant increase in a metal deposition in the respiratory tracts. Although the factors did not significantly affect the calculated respiratory deposition of harmful metals under typical e-cig usage assumption, the estimated hazard index exceeded 1.0.ConclusionThe calculated health risks suggest substantial risks of inhalation of metal aerosols from e-cig use.

The use of electronic nicotine delivery systems (ENDS), including disposable e-cigarettes, has been prevalent. Existing chemical analyses of ENDS focused on e-liquids rather than aerosols and failed to consider particle sizes and aerosol respiratory deposition fractions, which are key factors for inhalation doses. This study investigated the organic chemical and metal constituents in size-segregated ENDS aerosol and assessed the deposited doses and health risks of these substances. Aerosol chemical analyses were conducted on two popular disposable ENDS products: Puff Bar (Grape) and Air Bar (Watermelon Ice). An ENDS aerosol was generated and delivered into a Micro-Orifice Uniform Deposit Impactor to collect size-segregated aerosol samples, in which organic chemicals and metals were analyzed. Daily and lifetime doses for each chemical were estimated. Cancer and non-cancer risk assessments were conducted based on the deposited doses. We found that e-cigarette aerosol contains certain harmful organic chemicals and metals documented to result in respiratory problems. Estimated respiratory cancer risks corresponding to chromium from both ENDS products and nickel from Air Bar (Watermelon Ice) were substantially above the conventionally acceptable risk. The method, findings, and implications can contribute to the extant literature of ENDS toxicity studies as well as inform tobacco regulation and future large-scale studies.

In the late 1990s, despite years of efforts to understand and reduce coal worker’s pneumoconiosis (CWP) prevalence from more than 30% in 1970 to less than 4.2%, the level of occurrence among the US coal miners increased unexpectedly. The recent resurgence of lung diseases has raised concerns in the scientific and regulatory communities. In 2014, the United States Mine Safety and Health Administration (MSHA) issued a new dust rule changing the respirable coal mine dust (RCMD) exposure limits, measurement technology, and sampling protocol. The analysis for probable causes for the substantial increase in the CWP incidence rate is rather complicated. This paper aims to conduct a review of RCMD respiratory deposition, health effects, monitoring, regulations, and particle characteristics. The primary sources of RCMD along with the health risks from potential exposure are highlighted, and the current RCMD exposure regulations of the major coal producer countries are compared. A summary of RCMD characterization studies from 1972 to the present is provided. A review of the literature revealed that numerous factors, including geological and mining parameters, advancements in mining practices, particle characteristics, and monitoring approaches are considered to contribute to the recent resurgence of RCMD lung diseases. However, the root causes of the problem are still unknown. The effectiveness of the new dust rules in the United States will probably take years to be correctly assessed. Therefore, future research is needed to understand the relationship between RCMD particle characteristics and lung deposition, and the efficacy of current monitoring practices to measure the true dose of RCMD exposure.

We have, so far as we know, proposed and demonstrated the first 30 Gb/s four-level pulse amplitude modulation (PAM4) underwater wireless laser transmission (UWLT) system with an optical beam reducer/expander over 12.5-m piped underwater channel/2.5-m high-turbidity harbour underwater channel. In piped underwater links, the performances of PAM4 UWLT systems get better with beam reduction given a small amount of light absorbed by the piped water. In highly turbid harbour underwater links, the performances of PAM4 UWLT systems get better with beam expansion given a large amount of scattered light received by the optical receiver. The effect of high-turbidity harbour water that induces scattering angle (beam divergence) on beam diameter is analyzed and optimised to enhance the transmission performances. This proposed PAM4 UWLT system, which uses an optical beam reducer/expander, provides a practical choice for high transmission capacity and considerably develops clarity and high-turbidity scenarios. It presents promising features for affording a high-transmission-rate underwater optical wireless transmission and opening an access to accelerate wide applications of UWLT systems.

Ultrafine particle (i.e., smaller than 100 nm) in the ambient air is a significant public health issue. The inhalation and deposition of ultrafine particles in the human airways can lead to various adverse health effects. Loose-fitting types of masks are commonly used by the general public in some developing countries for protecting against ultrafine particles in the ambient environment. This research conducted a series of laboratory chamber experiments using two sets of particle sizers and two mannequin heads to study the mask efficiency of selected loose-fitting masks. Results acquired demonstrated that the cloth mask showed a low mask efficiency against ultrafine particles with the mask efficiency generally less than 0.4. The KN95 presented a better mask efficiency among all tested masks with the mask efficiency overall larger than 0.5. In addition, the effect of mask-wearing on the change of ultrafine particle airway deposition efficiency was also investigated in this study. The ultrafine particle deposition efficiency in the airway section studied was found to decrease due to mask-wearing, and the decreases of the deposition efficiencies were similar among all loose-fitting masks tested.

BackgroundExisting studies on the health effects of e-cigarettes focused on e-cigarette users themselves. To study the corresponding effects on passive vapers, it is crucial to quantify e-cigarette chemicals deposited in their airways.ObjectiveThis study proposed an innovative approach to estimate the deposited dose of e-cigarette chemicals in the passive vapers’ airways. The effect of the distance between active and passive vapers on the deposited dose was also examined.MethodsThe chemical constituent analysis was conducted to detect Nicotine and flavoring agents in e-cigarette aerosol. The Mobile Aerosol Lung Deposition Apparatus (MALDA) was employed to conduct aerosol respiratory deposition experiments in real-life settings to generate real-time data.ResultsFor e-cigarette aerosol in the ultrafine particle regime, the deposited doses in the alveolar region were on average 3.2 times higher than those in the head-to-TB airways, and the deposited dose in the passive vaper’s airways increased when being closer to the active vaper.SignificanceWith prolonged exposure and close proximity to active vapers, passive vapers may be at risk for potential health effects of harmful e-cigarette chemicals. The methodology developed in this study has laid the groundwork for future research on exposure assessment and health risk analysis for passive vaping.

The United States has witnessed a concerning surge in the incidence of diseases like Coal Workers’ Pneumoconiosis (CWP), despite numerous efforts aimed at prevention. This study delves into the realm of respiratory health by investigating the deposition of dust particles within the respiratory tract and lungs. By analyzing particles of varying sizes, shapes, velocities, and aerodynamic diameters, we aim to gain a comprehensive understanding of their impact on deposition patterns. This insight could potentially drive changes in dust exposure protocols within mining environments and improve monitoring practices. The interplay of several critical factors, including particle characteristics and an individual’s breathing patterns, plays a pivotal role in determining whether particles settle in the lungs or are exhaled. This paper provides a comprehensive literature review on Respirable Coal Mine Dust (RCMD), with a specific focus on examining particle deposition across different regions of the airway system and lungs. Additionally, we explore the utility of Computational Fluid Dynamics (CFD) in simulating particle behavior within the respiratory system. Predicting the precise behavior of dust particles within the respiratory airway poses a significant challenge. However, through numerical simulations, we aspire to enhance our understanding of strategies to mitigate total lung deposition by comprehensively modeling particle interactions within the respiratory system.

Abstract Background Atezolizumab plus bevacizumab (atezo-bev) has been recommended for advanced hepatocellular carcinoma (HCC). High-dose external beam radiotherapy (RT) is recognized for its excellent local tumor control. The efficacy and safety of concurrent atezo-bev with RT for highly advanced HCC has been minimally explored. Methods In this preliminary retrospective study, we assessed patients with highly advanced HCC, characterized by Vp4 portal vein thrombosis or tumors exceeding 50% of liver volume, who received concurrent atezo-bev and RT (group A). Group A included 13 patients who received proton radiation at a dose of 72.6 GyE in 22 fractions, and one patient who received photon radiation at a dose of 54 Gy in 18 fractions. This group was compared with 34 similar patients treated atezo-bev alone as a control (group B). The primary objectives were to evaluate the objective response rate (ORR), overall survival (OS), and safety. Results Baseline characteristics were similar between groups, except for a higher incidence of Vp4 portal vein thrombosis in group A (78.6% vs. 21.4%, P = .05). Group A achieved a higher ORR (50.0% vs. 11.8%, P < .01) and a longer OS (not reached vs. 5.5 months, P = .01) after a median follow-up of 5.2 months. Multivariate analysis indicated that concurrent RT independently favored longer OS (hazard ratio: 0.18; 95% CI, 0.05-0.63, P < .01). Group A did not increase any grade adverse events (78.6% vs. 58.8%, P = .19) or severe adverse events of grade ≥ 3 (14.3% vs. 14.7%, P = .97) compared to group B. Conclusions The concurrent high-dose external beam radiotherapy appears to safely enhance the effectiveness of atezolizumab plus bevacizumab for highly advanced patients with HCC. Further studies are warranted to confirm these findings. This preliminary retrospective study assessed patients with highly advanced hepatocellular carcinoma, exploring the efficacy and safety of concurrent atezolizumab plus bevacizumab with high-dose external beam radiotherapy for these patients.

Background Lenvatinib and atezolizumab plus bevacizumab(A + B) have been used for unresectable hepatocellular carcinoma (HCC) as first‐line therapy. Real‐world studies comparison of efficacy and safety in these two regimens are limited, we therefore conduct this study to investigate these issues. Methods We retrospectively reviewed patients received lenvatinib (n = 46) and A + B (n = 46) as first‐line systemic therapy for unresectable HCC in a tertiary medical center. Objective response rate (ORR), progression free survival (PFS), and overall survival (OS) were evaluated according to modified Response Evaluation Criteria in Solid Tumors (mRECIST). Inverse probability weighting (IPW) was performed for baseline clinical features balance. Results A total of 92 patients with median age of 63.8 year‐old, 78.3% male, 85.9% viral hepatitis infected, 67.4% BCLC stage C were enrolled. The median treatment and follow‐up duration were 4.7 months and 9.4 months, respectively. There was no significant difference in ORR (26.1% vs. 41.3%, p = 0.1226), PFS (5.9 vs. 5.3 months, p = 0.4066), and OS (not reached vs. not reached, p = 0.7128) between the lenvatinib and A + B groups. After IPW, the results of survival and response rate were also compared. Subgroup analysis suggested that using lenvatinib was not inferior to A + B in regards of PFS, including those with elder, Child‐Pugh class B, beyond up‐to‐seven, or portal vein invasion VP4 patients. Among the lenvatinib treated patients, multivariate analysis showed patients elder than 65‐year‐old was an independent predictor associated with shorter PFS (adjust HR: 2.085[0.914–4.753], p = 0.0213). The incidence rates of adverse events were similar between two groups (76 vs. 63%, p = 0.1740). Both of two regimens had similarly few impact on liver function by comparison of baseline, third month, and sixth month albumin‐bilirubin index and Child‐Pugh score. Conclusions The efficacy and safety of lenvatinib are similar to A + B as a first‐line systemic therapy for unresectable HCC. This study provides real‐world experience of lenvatinib and A + B as firstline treatment for unresectable HCC. The data showed that compared survival, response rate, and adverse events between two regimens.

It is expected that secondary exposure to e-cigarette aerosol (passive vaping) will soon become an issue of public health. Passive vaping inhales e-cigarette aerosol containing similar harmful substances as active vaping. However, parallel studies on passive vaping are minimal. Therefore, there is a need for passive vaping-related health risk studies to assess the impact of vaping on public health. This research conducted a series of experiments in a room using a puffing machine and the Mobile Aerosol Lung Deposition Apparatus (MALDA) to study e-cigarette aerosol respiratory deposition through passive vaping. The experimental data acquired were applied to estimate the deposited mass and health risks caused by toxic metals contained in e-cigarette aerosol. Five popular e-cigarette products were used in this study to generate e-cigarette aerosol for deposition experiments. In addition, size-segregated e-cigarette aerosol samples were collected, and metal compositions in the e-cigarette aerosol were analyzed. Results obtained showed that estimated non-cancer risks were all acceptable, with hazard quotient and hazard index all less than 1.0. The calculated cancer risks were also found acceptable, with lifetime excess cancer risk generally less than 1E-6. Therefore, the e-cigarettes tested and the passive vaping exposure scenarios studied do not seem to induce any potential for metal-related respiratory health effects.