BackgroundElectronic cigarettes (EC) deliver aerosol by heating fluid containing nicotine. Cartomizer EC combine the fluid chamber and heating element in a single unit. Because EC do not burn tobacco, they may be safer than conventional cigarettes. Their use is rapidly increasing worldwide with little prior testing of their aerosol.ObjectivesWe tested the hypothesis that EC aerosol contains metals derived from various components in EC.MethodsCartomizer contents and aerosols were analyzed using light and electron microscopy, cytotoxicity testing, x-ray microanalysis, particle counting, and inductively coupled plasma optical emission spectrometry.ResultsThe filament, a nickel-chromium wire, was coupled to a thicker copper wire coated with silver. The silver coating was sometimes missing. Four tin solder joints attached the wires to each other and coupled the copper/silver wire to the air tube and mouthpiece. All cartomizers had evidence of use before packaging (burn spots on the fibers and electrophoretic movement of fluid in the fibers). Fibers in two cartomizers had green deposits that contained copper. Centrifugation of the fibers produced large pellets containing tin. Tin particles and tin whiskers were identified in cartridge fluid and outer fibers. Cartomizer fluid with tin particles was cytotoxic in assays using human pulmonary fibroblasts. The aerosol contained particles >1 µm comprised of tin, silver, iron, nickel, aluminum, and silicate and nanoparticles (<100 nm) of tin, chromium and nickel. The concentrations of nine of eleven elements in EC aerosol were higher than or equal to the corresponding concentrations in conventional cigarette smoke. Many of the elements identified in EC aerosol are known to cause respiratory distress and disease.ConclusionsThe presence of metal and silicate particles in cartomizer aerosol demonstrates the need for improved quality control in EC design and manufacture and studies on how EC aerosol impacts the health of users and bystanders.

a b s t r a c tElectronic cigarettes (EC) and refill fluids are distributed with little information on their pre-and postnatal health effects. This study compares the cytotoxicity of EC refill fluids using embryonic and adult cells and examines the chemical characteristics of refill fluids using HPLC. Refill solutions were tested on human embryonic stem cells (hESC), mouse neural stem cells (mNSC), and human pulmonary fibroblasts (hPF) using the MTT assay, and NOAELs and IC 50 s were determined from dose-response curves. Spectral analysis was performed when products of the same flavor had different MTT outcomes. hESC and mNSC were generally more sensitive to refill solutions than hPF. All products from one company were cytotoxic to hESC and mNSC, but non-cytotoxic to hPF. Cytotoxicity was not due to nicotine, but was correlated with the number and concentration of chemicals used to flavor fluids. Additional studies are needed to fully assess the prenatal effect of refill fluids.

a b s t r a c tIn a prior study on electronic cigarette (EC) refill fluids, Cinnamon Ceylon was the most cytotoxic of 36 products tested. The purpose of the current study was to determine if high cytotoxicity is a general feature of cinnamon-flavored EC refill fluids and to identify the toxicant(s) in Cinnamon Ceylon. Eight cinnamon-flavored refill fluids, which were screened using the MTT assay, varied in their cytotoxicity with most being cytotoxic. Human embryonic stem cells were generally more sensitive than human adult pulmonary fibroblasts. Most products were highly volatile and produced vapors that impaired survival of cells in adjacent wells. Cinnamaldehyde (CAD), 2-methoxycinnamaldehyde (2MOCA), dipropylene glycol, and vanillin were identified in the cinnamon-flavored refill fluids using gas chromatography-mass spectrometry and high-pressure liquid chromatography (HPLC). When authentic standards of each chemical were tested using the MTT assay, only CAD and 2MOCA were highly cytotoxic. The amount of each chemical in the refill fluids was quantified using HPLC, and cytotoxicity correlated with the amount of CAD/ product. Duplicate bottles of the same product were similar, but varied in their concentrations of 2MOCA. These data show that the cinnamon flavorings in refill fluids are linked to cytotoxicity, which could adversely affect EC users.

Objective The aim of this study was to evaluate the distribution, concentration and toxicity of cinnamaldehyde in electronic cigarette (e-cigarette) refill fluids and aerosols. Methods The distribution and concentration of cinnamaldehyde were determined in 39 e-cigarette refill fluids plus 6 duplicates using gas chromatography and mass spectrometry (GC/MS). A cinnamaldehyde toxicity profile was established for embryonic and adult cells using a live cell imaging assay, immunocytochemistry, the comet assay and a recovery assay. Results Twenty of the 39 refill fluids contained cinnamaldehyde at concentrations that are cytotoxic to human embryonic and lung cells in the MTT assay. Cinnamon Ceylon aerosol produced in a cartomizer-style e-cigarette was cytotoxic. Cinnamon Ceylon aerosols and refill fluid aerosols (80% propylene glycol or cinnamaldehyde/propylene glycol) made using a tank/boxmod e-cigarette were more cytotoxic at 5 V than 3 V. Using GC/MS, aerosols produced at 5 V contained 10 additional peaks not present in aerosol generated at 3 V. One of these, 2,3-butandione (diacetyl), was confirmed with an authentic standard. Cinnamaldehyde depolymerised microtubules in human pulmonary fibroblasts. At concentrations that produced no effect in the MTT assay, cinnamaldehyde decreased growth, attachment and spreading; altered cell morphology and motility; increased DNA strand breaks; and increased cell death. At the MTT IC50 concentration, lung cells were unable to recover from cinnamaldehyde after 2 hours of treatment, whereas embryonic cells recovered after 8 hours. Conclusions Cinnamaldehyde-containing refill fluids and aerosols are cytotoxic, genotoxic and low concentrations adversely affect cell processes and survival. These data indicate that cinnamaldehyde in e-cigarette refill fluids/aerosols may impair homeostasis in the respiratory system.

Users with anomalous behaviors in online communication systems (e.g. email and social medial platforms) are potential threats to society. Automated anomaly detection based on advanced machine learning techniques has been developed to combat this issue; challenges remain, though, due to the difficulty of obtaining proper ground truth for model training and evaluation. Therefore, substantial human judgment on the automated analysis results is often required to better adjust the performance of anomaly detection. Unfortunately, techniques that allow users to understand the analysis results more efficiently, to make a confident judgment about anomalies, and to explore data in their context, are still lacking. In this paper, we propose a novel visual analysis system, TargetVue, which detects anomalous users via an unsupervised learning model and visualizes the behaviors of suspicious users in behavior-rich context through novel visualization designs and multiple coordinated contextual views. Particularly, TargetVue incorporates three new ego-centric glyphs to visually summarize a user's behaviors which effectively present the user's communication activities, features, and social interactions. An efficient layout method is proposed to place these glyphs on a triangle grid, which captures similarities among users and facilitates comparisons of behaviors of different users. We demonstrate the power of TargetVue through its application in a social bot detection challenge using Twitter data, a case study based on email records, and an interview with expert users. Our evaluation shows that TargetVue is beneficial to the detection of users with anomalous communication behaviors.