1,241 research outputs found
Recommended from our members
Meteorological and chemical factors controlling ozone formation in Seoul during MAPS-Seoul 2015
To understand the chemical mechanisms of controlling factors in ozone (O3) formation in early summer in Seoul, a comprehensive study encompassing measurement and modeling was conducted under the Megacity Air Pollution Study-Seoul (MAPS-Seoul) campaign. From May 18 to June 12, 2015, O3 and peroxyacetyl nitrate (PAN) were measured, along with their precursors, including NOx and volatile organic compounds (VOCs), at the Korea Institute of Science and Technology, located in northeast Seoul. VOCs were sampled in a canister twice a day (at 09:30 and 15:00) and analyzed via gas chromatography. The meteorological conditions and chemical regimes of the air masses were clearly distinguished during the study period. In May, NOx concentrations were higher with more pronounced diurnal cycles of precursors and O3 under constant westerly winds. By contrast, stagnant conditions developed in June, which reduced the inflow of primary emissions from the downtown area but increased the influence from the neighboring forest under high temperatures. As a result, the ratio of O3 to odd oxygen was higher in June, indicating a less efficient removal of O3 by NOx. In the same context, the air mass was chemically more aged with a higher NO2/NOx ratio and enhanced OH reactivity of oxygenated and biogenic VOCs in June. The overall measurement results suggest that O3 formation is slightly more sensitive to VOCs than to NOx in Seoul during this season, when O3 concentrations are the highest of the year
Synthesis and NOx removal performance of anatase S-TiO2/g-CN heterojunction formed from dye wastewater sludge.
In this study, sludges generated from Ti-based flocculation of dye wastewater were used to retrieve photoactive titania (S-TiO2). It was heterojunctioned with graphitic carbon nitride (g-CN) to augment photoactivity under UV/visible light irradiance. Later the as-prepared samples were utilized to remove nitrogen oxides (NOx) in the atmospheric condition through photocatalysis. Heterojunction between S-TiO2 and g-CN was prepared through facile calcination (@550 °C) of S-TiO2 and melamine mix. Advanced sample characterization was carried out and documented extensively. Successful heterojunction was confirmed from the assessment of morphological and optical attributes of the samples. Finally, the prepared samples' level of photoactivity was assessed through photooxidation of NOx under both UV and visible light irradiance. Enhanced photoactivity was observed in the prepared samples irrespective of the light types. After 1 h of UV/visible light-based photooxidation, the best sample STC4 was found to remove 15.18% and 9.16% of atmospheric NO, respectively. In STC4, the mixing ratio of S-TiO2, to melamine was maintained as 1:3. Moreover, the optical bandgap of STC4 was found as 2.65 eV, where for S-TiO2, it was 2.83 eV. Hence, the restrained rate of photogenerated charge recombination and tailored energy bandgap of the as-prepared samples were the primary factors for enhancing photoactivity
A mutate-and-map protocol for inferring base pairs in structured RNA
Chemical mapping is a widespread technique for structural analysis of nucleic
acids in which a molecule's reactivity to different probes is quantified at
single-nucleotide resolution and used to constrain structural modeling. This
experimental framework has been extensively revisited in the past decade with
new strategies for high-throughput read-outs, chemical modification, and rapid
data analysis. Recently, we have coupled the technique to high-throughput
mutagenesis. Point mutations of a base-paired nucleotide can lead to exposure
of not only that nucleotide but also its interaction partner. Carrying out the
mutation and mapping for the entire system gives an experimental approximation
of the molecules contact map. Here, we give our in-house protocol for this
mutate-and-map strategy, based on 96-well capillary electrophoresis, and we
provide practical tips on interpreting the data to infer nucleic acid
structure.Comment: 22 pages, 5 figure
Genotoxic agents promote the nuclear accumulation of annexin A2: role of annexin A2 in mitigating DNA damage
Annexin A2 is an abundant cellular protein that is mainly localized in the cytoplasm and plasma membrane, however a small population has been found in the nucleus, suggesting a nuclear function for the protein. Annexin A2 possesses a nuclear export sequence (NES) and inhibition of the NES is sufficient to cause nuclear accumulation. Here we show that annexin A2 accumulates in the nucleus in response to genotoxic agents including gamma-radiation, UV radiation, etoposide and chromium VI and that this event is mediated by the nuclear export sequence of annexin A2. Nuclear accumulation of annexin A2 is blocked by the antioxidant agent N-acetyl cysteine (NAC) and stimulated by hydrogen peroxide (H2O2), suggesting that this is a reactive oxygen species dependent event. In response to genotoxic agents, cells depleted of annexin A2 show enhanced phospho-histone H2AX and p53 levels, increased numbers of p53-binding protein 1 nuclear foci and increased levels of nuclear 8-oxo-2'-deoxyguanine, suggesting that annexin A2 plays a role in protecting DNA from damage. This is the first report showing the nuclear translocation of annexin A2 in response to genotoxic agents and its role in mitigating DNA damage.Natural Sciences and Engineering Research Council of Canada (NSERC); European Union [PCOFUND-GA-2009-246542]; Foundation for Science and Technology of Portugal; Beatrice Hunter Cancer Research Institute; Terry Fox Foundationinfo:eu-repo/semantics/publishedVersio
Non-L\'evy mobility patterns of Mexican Me'Phaa peasants searching for fuelwood
We measured mobility patterns that describe walking trajectories of
individual Me'Phaa peasants searching and collecting fuelwood in the forests of
"La Monta\~na de Guerrero" in Mexico. These one-day excursions typically follow
a mixed pattern of nearly-constant steps when individuals displace from their
homes towards potential collecting sites and a mixed pattern of steps of
different lengths when actually searching for fallen wood in the forest.
Displacements in the searching phase seem not to be compatible with L\'evy
flights described by power-laws with optimal scaling exponents. These findings
however can be interpreted in the light of deterministic searching on heavily
degraded landscapes where the interaction of the individuals with their scarce
environment produces alternative searching strategies than the expected L\'evy
flights. These results have important implications for future management and
restoration of degraded forests and the improvement of the ecological services
they may provide to their inhabitants.Comment: 15 pages, 4 figures. First version submitted to Human Ecology. The
final publication will be available at http://www.springerlink.co
SMEs' Confidentiality Concerns for Security Information Sharing
Small and medium-sized enterprises are considered an essential part of the EU
economy, however, highly vulnerable to cyberattacks. SMEs have specific
characteristics which separate them from large companies and influence their
adoption of good cybersecurity practices. To mitigate the SMEs' cybersecurity
adoption issues and raise their awareness of cyber threats, we have designed a
self-paced security assessment and capability improvement method, CYSEC. CYSEC
is a security awareness and training method that utilises self-reporting
questionnaires to collect companies' information about cybersecurity awareness,
practices, and vulnerabilities to generate automated recommendations for
counselling. However, confidentiality concerns about cybersecurity information
have an impact on companies' willingness to share their information. Security
information sharing decreases the risk of incidents and increases users'
self-efficacy in security awareness programs. This paper presents the results
of semi-structured interviews with seven chief information security officers of
SMEs to evaluate the impact of online consent communication on motivation for
information sharing. The results were analysed in respect of the Self
Determination Theory. The findings demonstrate that online consent with
multiple options for indicating a suitable level of agreement improved
motivation for information sharing. This allows many SMEs to participate in
security information sharing activities and supports security experts to have a
better overview of common vulnerabilities. The final publication is available
at Springer via https://doi.org/10.1007/978-3-030-57404-8_22Comment: 10 pages, 2 figures, 14th International Symposium on Human Aspects of
Information Security & Assurance (HAISA 2020
Automating the Communication of Cybersecurity Knowledge: Multi-Case Study
Cybersecurity is essential for the protection of companies against cyber
threats. Traditionally, cybersecurity experts assess and improve a company's
capabilities. However, many small and medium-sized businesses (SMBs) consider
such services not to be affordable. We explore an alternative do-it-yourself
(DIY) approach to bringing cybersecurity to SMBs. Our method and tool, CYSEC,
implements the Self-Determination Theory (SDT) to guide and motivate SMBs to
adopt good cybersecurity practices. CYSEC uses assessment questions and
recommendations to communicate cybersecurity knowledge to the end-user SMBs and
encourage self-motivated change. In this paper, the operationalisation of SDT
in CYSEC is presented and the results of a multi-case study shown that offer
insight into how SMBs adopted cybersecurity practices with CYSEC. Effective
automated cybersecurity communication depended on the SMB's hands-on skills,
tools adaptedness, and the users' willingness to documenting confidential
information. The SMBs wanted to learn in simple, incremental steps, allowing
them to understand what they do. An SMB's motivation to improve security
depended on the fitness of assessment questions and recommendations with the
SMB's business model and IT infrastructure. The results of this study indicate
that automated counselling can help many SMBs in security adoption. The final
publication is available at Springer via
https://link.springer.com/chapter/10.1007%2F978-3-030-59291-2_8Comment: 14 pages, 1 figure, 13th World Conference on Information Security
Educatio
A novel 3-hydroxypropionic acid-inducible promoter regulated by the LysR-type transcriptional activator protein MmsR of Pseudomonas denitrificans
MmsR (33.3 kDa) is a putative LysR-type transcriptional activator of Pseudomonas denitrificans. With the help of 3-hydroxypropionic acid (3-HP), an important platform chemical, MmsR positively regulates the expression of mmsA, which encodes methylmalonylsemialdehyde dehydrogenase, the enzyme involved in valine degradation. In the present study, the cellular function of MmsR and its binding to the regulatory DNA sequence of mmsA expression were investigated both in vivo and in vitro. Transcription of the mmsA was enhanced >140-fold in the presence of 3-HP. In the MmsR-responsive promoter region, two operators showing dyad symmetry, designated O-1 and O-2 and centered at the -79 and -28 positions, respectively, were present upstream of the mmsA transcription start site. An electrophoretic mobility shift assay indicated that MmsR binds to both operator sites for transcription activation, probably in cooperative manner. When either O-1 or O-2 or both regions were mutated, the inducibility by the MmsR-3-HP complex was significantly reduced or completely removed, indicating that both sites are required for transcription activation. A 3-HP sensor was developed by connecting the activation of MmsR to a green fluorescent readout. A more than 50-fold induction by 25 mM 3-HP was observed
The metabolic syndrome is not associated with homocysteinemia: The Persian Gulf Healthy Heart Study
Background: It is uncertain whether homocysteine
and the metabolic syndrome or its components are related
in the general population, as studies investigating the
association between homocysteine levels and insulin resistance
have shown conflicting results. Methods: In an ancillary
study to the Persian Gulf Healthy Heart Study, a cohort
study of Iranian men and women aged ≥25 yr, a random sample
of 1754 subjects were evaluated for the association of
plasma homocysteine levels and the metabolic syndrome using
National Cholesterol Education Program (NCEP)-Adult
Treatment Panel (ATP)-III criteria. Total homocysteine levels
and high sensitivity C-reactive protein (CRP) were determined
by enzyme-linked immunosorbent assays. Results: Subjects
with lower HDL-cholesterol and higher blood pressure
showed significantly higher homocysteine levels (p=0.001
and p<0.0001; respectively). There was no significant difference
in serum levels of homocysteine between subjects with
and without the metabolic syndrome. In multiple logistic regression
analysis, the metabolic syndrome did not show a
significant association with serum homocysteine levels after
adjusting for sex, age, smoking, fruit and vegetable intake
pattern, body mass index, and physical inactivity. Concurrent
elevated CRP levels and the metabolic syndrome also did not
show a significant association with serum homocysteine levels
after adjusting for sex, age, and lifestyle cardiovascular
risk factors. Conclusions: There was no association between
the metabolic syndrome using NCEP-ATPIII criteria and homocysteinemia
in this study. These data refute the hypothesis
that homocysteine levels are influenced by the metabolic
syndrome, at least in general healthy population
- …