BOE

G. O’Connell, D. Graff, Carl D. D'Ruiz

Abstract Changes in fifteen urine, blood and exhaled breath BoEs of HPHCs representing classes of compounds reported by FDA to be significant contributors to smoking-associated disease risks were measured in 105 clinical-confined subjects following randomization and a five-day forced-switch from usual brand conventional combustible cigarettes to: (i) exclusive commercial e-cigarette use; (ii) dual-use of commercial e-cigarettes and the subject’s usual cigarette brand; or (iii) discontinued use of all tobacco or nicotine products. Levels of urinary biomarkers in subjects that completely substituted their usual cigarette with e-cigarettes were significantly lower (29–95%) after 5 days. Percent reductions in eight of nine urinary BoEs were indistinguishable to smokers who had quit smoking, except for nicotine equivalents, which declined by 25–40%. Dual users who halved self-reported daily cigarette consumption with e-cigarettes exhibited reductions (7–38%) in eight of nine urinary biomarkers, but had increase (1–20%) in nicotine equivalents. Reductions were broadly proportional to the reduced numbers of cigarettes smoked. Dual user urinary nicotine equivalents were slightly higher, but not statistically significant. After 5 days, blood nicotine biomarker levels were lower in the cessation (75–96%) and exclusive use groups (11–83%); with dual users experiencing no significant reductions. All subjects experienced significant decreases in exhaled CO. Decreases in the cessation and exclusive groups ranged from 88–89% and 27–32% in dual users. Exhaled NO increased in the cessation and exclusive groups (46–63% respectively), whereas the dual users experienced minimal changes. Overall, smokers who completely or partially substituted conventional cigarettes with e-cigarettes over five days, experienced reductions in HPHCs.

T. G. Konstantinova, M. Andronic, D. A. Baklykov, V. E. Stukalova, D. Ezenkova, E. V. Zikiy, M. V. Bashinova, A. Solovev, E. Lotkov, I. A. Ryzhikov, I. A. Rodionov

Fused silica glass is a material of choice for micromechanical, microfluidic, and optical devices due to its chemical resistance, optical, electrical, and mechanical performance. Wet etching is the key method for fabricating of such microdevices. Protective mask integrity is a big challenge due extremely aggressive properties of etching solution. Here, we propose multilevel microstructures fabrication route based on fused silica deep etching through a stepped mask. First, we provide an analysis of a fused silica dissolution mechanism in buffered oxide etching (BOE) solution and calculate the main fluoride fractions like $${HF}_{2}^{-}$$ HF 2 - , $${F}^{-}$$ F - , $${(HF)}_{2}$$ ( H F ) 2 as a function of pH and NH_4F:HF ratio. Then, we experimentally investigate the influence of BOE composition (1:1–14:1) on the mask resistance, etch rate and profile isotropy during deep etching through a metal/photoresist mask. Finally, we demonstrate a high-quality multilevel over-200 μm etching process with the rate up to 3 μm/min, which could be of a great interest for advanced microdevices with flexure suspensions, inertial masses, microchannels, and through-wafer holes.

Meng Liu, S. Liang, Dongfang Shi, Siyuan Yang, Yu Lei, Tie Li, Yuelin Wang

Nanoscale air/vacuum channel devices have shown great potential in extreme environments, high speed and low power consumption applications. Progress in fabrication, structure and material optimization keeps emerging. However, it remains challenging to achieve a stable large current emission at low voltages, which limit the practical application of nanoscale air/vacuum channel devices. Here, a vertical structure consisting of two asymmetric flat emitters and a sub-100 nm air channel is proposed and fabricated by a low-cost and IC compatible BOE etching process. Typical diode characteristics have been demonstrated and controlled by the channel length. More importantly, emission currents up to several hundreds of microamp have been achieved in air with voltages lower than 2 volts and remain stable under sweep, fixed and periodic voltages. Along with the stable emission, a rise/fall time of 25 ns has been achieved for 1 MHz input signal. The present study provides an emission-stable nanoscale air channel diode with good manufacturing and integration possibilities, which can be an element for the future logic circuits of nanoscale air/vacuum channel electronics.

Until recently, few efforts have been made to systematically measure and aggregate the nominal value of the different types of sovereign government debt in default. To help fill this gap, the Bank of Canada (BoC) developed a comprehensive database of sovereign defaults that is posted on its website and updated in partnership with the Bank of England (BoE). Our database draws on previously published datasets compiled by various public and private sector sources. It combines elements of these, together with new information, to develop comprehensive estimates of stocks of government obligations in default. These include bonds and other marketable securities, bank loans and official loans, valued in US dollars, for the years 1960 to 2018 on both a country-by-country and a global basis. This update of the BoC-BoE database, and future updates, will be useful to researchers analyzing the economic and financial effects of individual sovereign defaults and, importantly, the impact on global financial stability of episodes involving multiple sovereign defaults.

J. Bailón-Elvira, M. Cobo, E. Herrera-Viedma, A. G. López-Herrera

Abstract Since Internet was born most people can access fully free to a lot sources of information. Every day a lot of web pages are created and new content is uploaded and shared. Never in the history the humans has been more informed but also uninformed due the huge amount of information that can be access. When we are looking for something in any search engine the results are too many for reading and filtering one by one. Recommended Systems (RS) was created to help us to discriminate and filter these information according to ours preferences. This contribution analyses the RS of the official agency of publications in Spain (BOE), which is known as "Mi BOE". The way this RS works was analysed, and all the meta-data of the published documents were analysed in order to know the coverage of the system. The results of our analysis show that more than 89% of the documents cannot be recommended, because they are not well described at the documentary level, some of their key meta-data are empty. So, this contribution proposes a method to label documents automatically based on Latent Dirichlet Allocation (LDA). The results are that using this approach the system could recommend (at a theoretical point of view) more than twice of documents that it now does, 11% vs 23% after applied this approach.