145 results on '"Siek P"'
Search Results
2. Near surface oxidation of elemental mercury leads to mercury exposure in the Arctic Ocean biota
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Seung Hyeon Lim, Younggwang Kim, Laura C. Motta, Eun Jin Yang, Tae Siek Rhee, Jong Kuk Hong, Seunghee Han, and Sae Yun Kwon
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Science - Abstract
Abstract Atmospheric mercury (Hg(0), Hg(II)) and riverine exported Hg (Hg(II)) are proposed as important Hg sources to the Arctic Ocean. As plankton cannot passively uptake Hg(0), gaseous Hg(0) has to be oxidized to be bioavailable. Here, we measured Hg isotope ratios in zooplankton, Arctic cod, total gaseous Hg, sediment, seawater, and snowpack from the Bering Strait, the Chukchi Sea, and the Beaufort Sea. The Δ200Hg, used to differentiate between Hg(0) and Hg(II), shows, on average, 70% of Hg(0) in all biota and differs with seawater Δ200Hg (Hg(II)). Since Δ200Hg anomalies occur via tropospheric Hg(0) oxidation, we propose that near-surface Hg(0) oxidation via terrestrial vegetation, coastally evaded halogens, and sea salt aerosols, which preserve Δ200Hg of Hg(0) upon oxidation, supply bioavailable Hg(II) pools in seawater. Our study highlights sources and pathways in which Hg(0) poses potential ecological risks to the Arctic Ocean biota.
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- 2024
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3. Statistical Survey of Chemical and Geometric Patterns on Protein Surfaces as a Blueprint for Protein‐Mimicking Nanoparticles
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John M. McBride, Aleksei Koshevarnikov, Marta Siek, Bartosz A. Grzybowski, and Tsvi Tlusty
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charge‐hydrophobicity patterns ,mixed‐charge nanoparticles ,protein surface geometries ,protein surfaces ,protein‐mimicking nanoparticles ,quinary structures ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Despite recent breakthroughs in understanding how protein sequence relates to structure and function, considerably less attention has been paid to the general features of protein surfaces beyond those regions involved in binding and catalysis. This article provides a systematic survey of the universe of protein surfaces and quantifies the sizes, shapes, and curvatures of the positively/negatively charged and hydrophobic/hydrophilic surface patches as well as correlations between such patches. It then compares these statistics with the metrics characterizing nanoparticles functionalized with ligands terminated with positively and negatively charged ligands. These particles are of particular interest because they are also surface patchy and have been shown to exhibit both antibiotic and anticancer activities—via selective interactions against various cellular structures—prompting loose analogies to proteins. The analyses support such analogies in several respects (e.g., patterns of charged protrusions and hydrophobic niches similar to those observed in proteins), although there are also significant differences. Looking forward, this work provides a blueprint for the rational design of synthetic nano‐objects with further enhanced mimicry of proteins’ surface properties.
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- 2024
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4. Active learning guides discovery of a champion four-metal perovskite oxide for oxygen evolution electrocatalysis
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Moon, Junseok, Beker, Wiktor, Siek, Marta, Kim, Jiheon, Lee, Hyeon Seok, Hyeon, Taeghwan, and Grzybowski, Bartosz A.
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- 2024
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5. Decentralized mobility hubs in urban residential neighborhoods improve the contribution of carsharing to sustainable mobility: findings from a quasi-experimental study
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Czarnetzki, Felix and Siek, Florian
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- 2023
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6. TetR-like regulator BP1026B_II1561 controls aromatic amino acid biosynthesis and intracellular pathogenesis in Burkholderia pseudomallei
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Ian A. McMillan, Michael H. Norris, Yun Heacock-Kang, Jan Zarzycki-Siek, Zhenxin Sun, Brooke A. Hartney, Liliana K. Filipowska, M. Nurul Islam, Dean C. Crick, Bradley R. Borlee, and Tung T. Hoang
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bacteriology ,Burkholderia pseudomallei ,melioidosis ,transcriptional regulation ,pathogenesis ,Microbiology ,QR1-502 - Abstract
Burkholderia pseudomallei (Bp) causes the tropical disease melioidosis that afflicts an estimated 165,000 people each year. Bp is a facultative intracellular pathogen that transits through distinct intracellular stages including attachment to host cells, invasion through the endocytic pathway, escape from the endosome, replication in the cytoplasm, generation of protrusions towards neighboring cells, and host cell fusion allowing Bp infection to spread without exiting the intracellular environment. We have identified a TetR-like transcriptional regulator, BP1026B_II1561, that is up-regulated during the late stages of infection as Bp protrudes toward neighboring cells. We have characterized BP1026B_II1561 and determined that it has a role in pathogenesis. A deletional mutant of BP1026B_II1561 is attenuated in RAW264.7 macrophage and BALB/c mouse models of infection. Using RNA-seq, we found that BP1026B_II1561 controls secondary metabolite biosynthesis, fatty acid degradation, and propanoate metabolism. In addition, we identified that BP1026B_II1561 directly controls expression of an outer membrane porin and genes in the shikimate biosynthetic pathway using ChIP-seq. Transposon mutants of genes within the BP1026B_II1561 regulon show defects during intracellular replication in RAW264.7 cells confirming the role of this transcriptional regulator and the pathways it controls in pathogenesis. BP1026B_II1561 also up-regulates the majority of the enzymes in shikimate and tryptophan biosynthetic pathways, suggesting their importance for Bp physiology. To investigate this, we tested fluorinated analogs of anthranilate and tryptophan, intermediates and products of the shikimate and tryptophan biosynthetic pathways, respectively, and showed inhibition of Bp growth at nanomolar concentrations. The expression of these pathways by BP1026b_II1561 and during intracellular infection combined with the inhibition of Bp growth by fluorotryptophan/anthranilate highlights these pathways as potential targets for therapeutic intervention against melioidosis. In the present study, we have identified BP1026B_II1561 as a critical transcriptional regulator for Bp pathogenesis and partially characterized its role during host cell infection.
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- 2024
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7. Recent Development of High-PCE CMOS RF-DC Rectifier With Wide PIN Dynamic Range: Strategies and Trends—Review
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Boon Chiat Terence Teo, Wu Cong Lim, Xian Yang Lim, Venkadasamy Navaneethan, and Liter Siek
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CMOS ,energy harvesting ,wireless power transfer (WPT) ,RF-DC converter ,rectifier ,efficiency ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
This review explores the various strategies used to widen the input power (P $_{\mathrm {IN}}$ ) dynamic range of an RF-DC rectifier and analyzes the recent developments reported in the literature. This development is insightful as the PIN dynamic range is crucial for systems adopting wireless power transfer (WPT) or wireless energy harvesting (EH) for both near- and far-field applications to mitigate the reliance on the battery as its primary power source. However, the RF-DC rectifier exhibits non-linear characteristics, resulting in a narrow PIN band for reasonable power conversion efficiency (PCE). The different strategies reported in the literature are discussed and classified into three main concepts: reconfigurable, multi-path, and self-biased rectifiers. Despite having different design constraints and considerations during the inception of the reported work in the literature, this article analyzes and provides the general development trend, merits, and demerits.
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- 2024
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8. International Education within ASEAN and the Rise of Asian Century
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Yodpet, Worapot, Salvador Quetzal, Amelio, Siek, Nguon, Vebrina Sihite, Fenny, Alegado, Paul John Edrada, Balakrishnan, Vishalache, Green, Benjamin, and Hollings, Stephanie
- Abstract
This collective writing paper brings together writers from Southeast Asia and the Western world to highlight challenges and opportunities for ASEAN (Association of Southeast Asian Nations) and its education in the rising of the Asian Century. The inspiration for this project was started by Michael A. Peters' conception of collective writing and the Asian Century. ASEAN is diverse in terms of economy and society; a look from different angles will help to improve policy and practice of ASEAN. Multiple scholars have contributed to creating a series of arguments and explications towards a philosophical stance, and collaboration in higher education to build novel solutions regarding contemporary knowledge and ASEAN practices. Overall, this article illustrates ASEAN International Education (IE) circumstances and possibilities considering statistical data and past experience from transregional perspectives and diverse academic institutions.
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- 2023
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9. Application of clusterization algorithms for analysis of semivolatile pollutants in Arkhangelsk snow
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Mazur, D. M., Sosnova, A. A., Latkin, T. B., Artaev, B. V., Siek, K., Koluntaev, D. A., and Lebedev, A. T.
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- 2023
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10. Unexpected nascent atmospheric emissions of three ozone-depleting hydrochlorofluorocarbons
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Vollmer, Martin K, Mühle, Jens, Henne, Stephan, Young, Dickon, Rigby, Matthew, Mitrevski, Blagoj, Park, Sunyoung, Lunder, Chris R, Rhee, Tae Siek, Harth, Christina M, Hill, Matthias, Langenfelds, Ray L, Guillevic, Myriam, Schlauri, Paul M, Hermansen, Ove, Arduini, Jgor, Wang, Ray HJ, Salameh, Peter K, Maione, Michela, Krummel, Paul B, Reimann, Stefan, O’Doherty, Simon, Simmonds, Peter G, Fraser, Paul J, Prinn, Ronald G, Weiss, Ray F, and Steele, L Paul
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Montreal Protocol ,atmospheric composition ,ozone depletion - Abstract
Global and regional atmospheric measurements and modeling can play key roles in discovering and quantifying unexpected nascent emissions of environmentally important substances. We focus here on three hydrochlorofluorocarbons (HCFCs) that are restricted by the Montreal Protocol because of their roles in stratospheric ozone depletion. Based on measurements of archived air samples and on in situ measurements at stations of the Advanced Global Atmospheric Gases Experiment (AGAGE) network, we report global abundances, trends, and regional enhancements for HCFC-132b ([Formula: see text]), which is newly discovered in the atmosphere, and updated results for HCFC-133a ([Formula: see text]) and HCFC-31 ([Formula: see text]ClF). No purposeful end-use is known for any of these compounds. We find that HCFC-132b appeared in the atmosphere 20 y ago and that its global emissions increased to 1.1 Gg⋅y-1 by 2019. Regional top-down emission estimates for East Asia, based on high-frequency measurements for 2016-2019, account for ∼95% of the global HCFC-132b emissions and for ∼80% of the global HCFC-133a emissions of 2.3 Gg⋅y-1 during this period. Global emissions of HCFC-31 for the same period are 0.71 Gg⋅y-1 Small European emissions of HCFC-132b and HCFC-133a, found in southeastern France, ceased in early 2017 when a fluorocarbon production facility in that area closed. Although unreported emissive end-uses cannot be ruled out, all three compounds are most likely emitted as intermediate by-products in chemical production pathways. Identification of harmful emissions to the atmosphere at an early stage can guide the effective development of global and regional environmental policy.
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- 2021
11. Charge mosaics on contact-electrified dielectrics result from polarity-inverting discharges
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Sobolev, Yaroslav I., Adamkiewicz, Witold, Siek, Marta, and Grzybowski, Bartosz A.
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- 2022
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12. Potential impact of the sea-ice ecosystem to the polar seas biogeochemistry
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Young Shin Kwon, Tae Siek Rhee, and Karsten Bolding
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sympagic diatoms ,sympagic ecosystem model ,polar marine ecosystem ,POC flux ,ERSEM ,SPBM ,Science ,General. Including nature conservation, geographical distribution ,QH1-199.5 - Abstract
We used a one-dimensional vertical transport model, the sympagic-pelagic-benthic vertical transport model (SPBM) to explore the impact of sea-ice presence on phytoplankton phenology and biogeochemical dynamics. In the model, we introduced new parameter values for sympagic diatoms using ERSEM (European Regional Seas Ecosystem Model) in addition to the existing phytoplankton groups in the sea-ice model. We found that different groups of primary producers exhibit distinct spatial and temporal variabilities in both the sea-ice and water column depending on their physiological and biogeochemical properties. In particular, we discovered that the biomass of pelagic diatoms during the bloom season is strongly influenced by the release of sympagic algal cells during the early spring. This suggests the potential significance of sympagic algae seeding for the occurrence of pelagic diatom blooms in the Amundsen Sea. Notably, our model also indicates a potential connection between the earlier peak in particulate organic carbon flux and the release of sympagic-algae-associated particles from the sea ice, followed by their rapid sinking. Previous studies relying solely on observational data did not fully account for this mechanism. Our findings emphasize the importance of understanding the role of sympagic algae in the polar ecosystem and carbon cycle, and shed light on the complex biogeochemical dynamics associated with the sea-ice ecosystem in the polar seas.
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- 2023
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13. Last-use opacity: a strong safety property for transactional memory with prerelease support
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Siek, Konrad and Wojciechowski, Paweł T.
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- 2022
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14. Analysis of energy consumption bounds in CMOS current-steering digital-to-analog converters
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Morales Chacón, Oscar, Wikner, J. Jacob, Svensson, Christer, Siek, Liter, and Alvandpour, Atila
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- 2022
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15. Seismic airgun sound propagation in shallow water of the East Siberian shelf and its prediction with the measured source signature
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Dong-Gyun Han, Sookwan Kim, Martin Landrø, Wuju Son, Dae Hyeok Lee, Young Geul Yoon, Jee Woong Choi, Eun Jin Yang, Yeonjin Choi, Young Keun Jin, Jong Kuk Hong, Sung-Ho Kang, Tae Siek Rhee, Hyoung Chul Shin, and Hyoung Sul La
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seismic airgun sound ,underwater ambient noise ,sound propagation ,transmission loss ,source signature ,acoustic modeling ,Science ,General. Including nature conservation, geographical distribution ,QH1-199.5 - Abstract
Seismic airgun sound was measured with an autonomous passive acoustic recorder as a function of distance from 18.6 to 164.2 km in shallow water (
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- 2023
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16. The miscarriage circle of care: towards leveraging online spaces for social support
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Alqassim, Mona Y., Kresnye, K. Cassie, Siek, Katie A., Lee, John, and Wolters, Maria K.
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- 2022
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17. Heat inactivation of clinical COVID-19 samples on an industrial scale for low risk and efficient high-throughput qRT-PCR diagnostic testing
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Delpuech, Oona, Douthwaite, Julie A., Hill, Thomas, Niranjan, Dhevahi, Malintan, Nancy T., Duvoisin, Hannah, Elliott, Jane, Goodfellow, Ian, Hosmillo, Myra, Orton, Alexandra L., Taylor, Molly A., Brankin, Christopher, Pitt, Haidee, Ross-Thriepland, Douglas, Siek, Magdalena, Cuthbert, Anna, Richards, Ian, Ferdinand, John R., Barker, Colin, Shaw, Robert, Ariani, Cristina, Waddell, Ian, Rees, Steve, Green, Clive, Clark, Roger, Upadhyay, Abhishek, and Howes, Rob
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- 2022
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18. Heat inactivation of clinical COVID-19 samples on an industrial scale for low risk and efficient high-throughput qRT-PCR diagnostic testing
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Oona Delpuech, Julie A. Douthwaite, Thomas Hill, Dhevahi Niranjan, Nancy T. Malintan, Hannah Duvoisin, Jane Elliott, Ian Goodfellow, Myra Hosmillo, Alexandra L. Orton, Molly A. Taylor, Christopher Brankin, Haidee Pitt, Douglas Ross-Thriepland, Magdalena Siek, Anna Cuthbert, Ian Richards, John R. Ferdinand, Colin Barker, Robert Shaw, Cristina Ariani, Ian Waddell, Steve Rees, Clive Green, Roger Clark, Abhishek Upadhyay, and Rob Howes
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Medicine ,Science - Abstract
Abstract We report the development of a large scale process for heat inactivation of clinical COVID-19 samples prior to laboratory processing for detection of SARS-CoV-2 by RT-qPCR. With more than 266 million confirmed cases, over 5.26 million deaths already recorded at the time of writing, COVID-19 continues to spread in many parts of the world. Consequently, mass testing for SARS-CoV-2 will remain at the forefront of the COVID-19 response and prevention for the near future. Due to biosafety considerations the standard testing process requires a significant amount of manual handling of patient samples within calibrated microbiological safety cabinets. This makes the process expensive, effects operator ergonomics and restricts testing to higher containment level laboratories. We have successfully modified the process by using industrial catering ovens for bulk heat inactivation of oropharyngeal/nasopharyngeal swab samples within their secondary containment packaging before processing in the lab to enable all subsequent activities to be performed in the open laboratory. As part of a validation process, we tested greater than 1200 clinical COVID-19 samples and showed less than 1 Cq loss in RT-qPCR test sensitivity. We also demonstrate the bulk heat inactivation protocol inactivates a murine surrogate of human SARS-CoV-2. Using bulk heat inactivation, the assay is no longer reliant on containment level 2 facilities and practices, which reduces cost, improves operator safety and ergonomics and makes the process scalable. In addition, heating as the sole method of virus inactivation is ideally suited to streamlined and more rapid workflows such as ‘direct to PCR’ assays that do not involve RNA extraction or chemical neutralisation methods.
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- 2022
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19. The miscarriage circle of care: towards leveraging online spaces for social support
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Mona Y. Alqassim, K. Cassie Kresnye, Katie A. Siek, John Lee, and Maria K. Wolters
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Miscarriage ,Pregnancy loss ,Social support ,Care network ,Circle of care ,eHealth ,Gynecology and obstetrics ,RG1-991 ,Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background Lack of social support during and after miscarriage can greatly affect mental wellbeing. With miscarriages being a common experience, there remains a discrepancy in the social support received after a pregnancy is lost. Method 42 people who had experienced at least one miscarriage took part in an Asynchronous Remote Community (ARC) study. The study involved 16 activities (discussions, creative tasks, and surveys) in two closed, secret Facebook groups over eight weeks. Descriptive statistics were used to analyse quantitative data, and content analysis was used for qualitative data. Results There were two main miscarriage care networks, formal (health care providers) and informal (friends, family, work colleagues). The formal care network was the most trusted informational support source, while the informal care network was the main source of tangible support. However, often, participants’ care networks were unable to provide sufficient informational, emotional, esteem, and network support. Peers who also had experienced miscarriage played a crucial role in addressing these gaps in social support. Technology use varied greatly, with smartphone use as the only common denominator. While there was a range of online support sources, participants tended to focus on only a few, and there was no single common preferred source. Discussion We propose a Miscarriage Circle of Care Model (MCCM), with peer advisors playing a central role in improving communication channels and social support provision. We show how the MCCM can be used to identify gaps in service provision and opportunities where technology can be leveraged to fill those gaps.
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- 2022
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20. A virulence activator of a surface attachment protein in Burkholderia pseudomallei acts as a global regulator of other membrane-associated virulence factors
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Zhenxin Sun, Yun Heacock-Kang, Ian A. McMillan, Darlene Cabanas, Jan Zarzycki-Siek, and Tung T. Hoang
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Burkholderia pseudomallei ,transposon mutagenesis ,Tn-Seq ,RNA-Seq ,bacterial cell envelope ,gene regulation ,Microbiology ,QR1-502 - Abstract
Burkholderia pseudomallei (Bp), causing a highly fatal disease called melioidosis, is a facultative intracellular pathogen that attaches and invades a variety of cell types. We previously identified BP1026B_I0091 as a surface attachment protein (Sap1) and an essential virulence factor, contributing to Bp pathogenesis in vitro and in vivo. The expression of sap1 is regulated at different stages of Bp intracellular lifecycle by unidentified regulator(s). Here, we identified SapR (BP1026B_II1046) as a transcriptional regulator that activates sap1, using a high-throughput transposon mutagenesis screen in combination with Tn-Seq. Consistent with phenotypes of the Δsap1 mutant, the ΔsapR activator mutant exhibited a significant reduction in Bp attachment to the host cell, leading to subsequent decreased intracellular replication. RNA-Seq analysis further revealed that SapR regulates sap1. The regulation of sap1 by SapR was confirmed quantitatively by qRT-PCR, which also validated the RNA-Seq data. SapR globally regulates genes associated with the bacterial membrane in response to diverse environments, and some of the genes regulated by SapR are virulence factors that are required for Bp intracellular infection (e.g., type III and type VI secretion systems). This study has identified the complex SapR regulatory network and its importance as an activator of an essential Sap1 attachment factor.
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- 2023
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21. Fate of Tebuconazole in Polish Mineral Soils – Results of Simulations with FOCUS PELMO
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Marcin Maciej Siek and Tadeusz Paszko
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leaching ,retention ,tebuconazole ,focus pelmo simulations ,Environmental technology. Sanitary engineering ,TD1-1066 ,Environmental sciences ,GE1-350 - Abstract
The degradation of tebuconazole in the majority of Polish mineral soils with low organic carbon content is slow, and its adsorption is especially low in subsoils. Therefore, the fate of tebuconazole in these soils cannot be predicted based on results of adsorption and degradation experiments carried out in typical soils of the European Union. For this reason, simulations of tebuconazole accumulation in Polish soils and its leaching to groundwater were carried out. The cultivation of winter cereals and winter oilseed rape was simulated using FOCUS PELMO in six Arenosol, Luvisol, and Chernozem profiles, representing 59% of Polish arable mineral soils. The simulations indicated that almost all fungicide that reached the soil surface was retained in the topsoil layer of 0–15 cm. The highest concentrations (range of 0.069–0.320 mg/kg) were estimated for the layer 0–5 cm. The results suggested that runoff can be the principal source of tebuconazole in surface water. It was found that the majority of tebuconazole that reached the soils was microbiologically degraded. However, in years with weather conditions that were unfavorable for degradation, up to 11% of tebuconazole that reached the soils remain undegraded. In addition to the accumulation of tebuconazole in the topsoils, the simulations indicated its very slow but constant penetration into the subsoils. The estimated concentrations of tebuconazole in percolate water were low: < 0.02 μg/L at the depth of 25 cm, < 0.002 μg/L at the depth of 75 cm, and trace concentrations at the depth of 1 m in one profile. The obtained results were consistent with results of monitoring studies available in literature.
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- 2021
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22. Identification of ventilated and submarine glacial meltwaters in the Amundsen Sea, Antarctica, using noble gases
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DongYoub Shin, Doshik Hahm, Tae-Wan Kim, Tae Siek Rhee, SangHoon Lee, Keyhong Park, Jisoo Park, Young Shin Kwon, Mi Seon Kim, and Tongsup Lee
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glacial meltwater ,noble gases ,optimum multiparameter analysis ,Amundsen Sea ,basal melting ,meteoric water ,Science ,General. Including nature conservation, geographical distribution ,QH1-199.5 - Abstract
To delineate the glacial meltwater distribution, we used five noble gases for optimum multiparameter analysis (OMPA) of the water masses in the Dotson-Getz Trough (DGT), Amundsen Sea. The increased number of tracers allowed us to define potential source waters at the surface, which have not been possible with a small set of tracers. The highest submarine meltwater (SMW) fraction (~0.6%) was present at the depth of ~450 m near the Dotson Ice Shelf. The SMW appeared to travel beyond the continental shelf break along an isopycnal layer. Air-equilibrated freshwater (up to 1.5%), presumably ventilated SMW (VMW) and surface melts, was present in the surface layer (
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- 2022
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23. Transcriptomic landscape of blood platelets in healthy donors
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Anna Supernat, Marta Popęda, Krzysztof Pastuszak, Myron G. Best, Peter Grešner, Sjors In ’t Veld, Bartłomiej Siek, Natalia Bednarz-Knoll, Matthew T. Rondina, Tomasz Stokowy, Thomas Wurdinger, Jacek Jassem, and Anna J. Żaczek
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Medicine ,Science - Abstract
Abstract Blood platelet RNA-sequencing is increasingly used among the scientific community. Aberrant platelet transcriptome is common in cancer or cardiovascular disease, but reference data on platelet RNA content in healthy individuals are scarce and merit complex investigation. We sought to explore the dynamics of platelet transcriptome. Datasets from 204 healthy donors were used for the analysis of splice variants, particularly with regard to age, sex, blood storage time, unit of collection or library size. Genes B2M, PPBP, TMSB4X, ACTB, FTL, CLU, PF4, F13A1, GNAS, SPARC, PTMA, TAGLN2, OAZ1 and OST4 demonstrated the highest expression in the analysed cohort, remaining substantial transcription consistency. CSF3R gene was found upregulated in males (fold change 2.10, FDR q
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- 2021
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24. The Influence of National Cultural Attributes on Locally Produced Designs: Case Study of Malaysian Design
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Hwee Ling Siek and Cheng Ean Lee
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national cultural attributes ,malaysian design ,multicultural society ,Ethnology. Social and cultural anthropology ,GN301-674 - Abstract
This paper examines the influence of national cultural attributes on locally produced designs (i.e. comics, animation, commercial advertisements, printed materials and graphics). Drawing from the inconsistent results of past literature on influences of national cultural attributes on design; it is considered an under-researched area of the important role of cultural values on designs, specifically in the Malaysia context, in which cultural differences among different ethnic groups exist. Because of the paucity of research in this area, this study adopted a quantitative research approach with results derived from the content-analysis of 18 Malaysian designs using a visual preference survey by six experts from the design industry in Malaysia. This study incorporates two stages of sample screenings of a visual preference survey with brief interviews; results show that Malaysian designs need to adhere strictly to requirements and specifications set by the Malaysian authorities; incorporation of Islamic values and code of conduct to reflect the racial harmony and national ideology; and some unique characteristics of the respective ethnic groups in Malaysia were not upheld, thus, they gradually disappeared and/or were blended in the designs. The results and discussion from this study extend the literature on Malaysian design and provide practical implications on how local design industries could produce designs which abide by the boundaries of a Malaysian pluralistic society.
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- 2021
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25. Johannes Schmiedt (1623–1690)
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Pekacka-Falkowska, Katarzyna and Siek, Bartlomiej
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- 2021
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26. Identification of a PadR-type regulator essential for intracellular pathogenesis of Burkholderia pseudomallei
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Ian A. McMillan, Michael H. Norris, Jan Zarzycki-Siek, Yun Heacock-Kang, Zhenxin Sun, Bradley R. Borlee, and Tung T. Hoang
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Medicine ,Science - Abstract
Abstract Burkholderia pseudomallei (Bp) is the causative agent of melioidosis, a disease endemic to the tropics. Melioidosis manifests in various ways ranging from acute skin lesions to pneumonia and, in rare cases, infection of the central nervous system. Bp is a facultative intracellular pathogen and it can infect various cell types. The Bp intracellular lifecycle has been partially elucidated and is highly complex. Herein, we have identified a transcriptional regulator, BP1026B_II1198, that is differentially expressed as Bp transits through host cells. A deletion mutant of BP1026B_II1198 was attenuated in RAW264.7 cell and BALB/c mouse infection. To further characterize the function of this transcriptional regulator, we endeavored to determine the regulon of BP1026B_II1198. RNA-seq analysis showed the global picture of genes regulated while ChIP-seq analysis identified two specific BP1026B_II1198 binding regions on chromosome II. We investigated the transposon mutants of these genes controlled by BP1026B_II1198 and confirmed that these genes contribute to pathogenesis in RAW264.7 murine macrophage cells. Taken together, the data presented here shed light on the regulon of BP1026B_II1198 and its role during intracellular infection and highlights an integral portion of the highly complex regulation network of Bp during host infection.
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- 2021
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27. The Burkholderia pseudomallei intracellular ‘TRANSITome’
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Yun Heacock-Kang, Ian A. McMillan, Michael H. Norris, Zhenxin Sun, Jan Zarzycki-Siek, Andrew P. Bluhm, Darlene Cabanas, Robert E. Norton, Natkunam Ketheesan, Jeff F. Miller, Herbert P. Schweizer, and Tung T. Hoang
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Science - Abstract
Prokaryotic cell transcriptomics has been limited to mixed or sub-population dynamics and individual cells within heterogeneous populations. Here the authors develop a ‘TRANSITomic’ approach to profile transcriptomes of single Burkholderia pseudomallei cells as they transit through host cell infection.
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- 2021
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28. A Low-Power Quadrature LO Generator With Mutual Power-Supply Rejection Technique
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Ao Zhou, Xin Ding, Chirn Chye Boon, Liter Siek, Yuan Liang, and Yangtao Dong
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CMOS ,current-mode-logic (CML) ,frequency divider (FD) ,low-power consumption ,mutual power-supply rejection (M-PSR) ,supply sensitivity ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
This paper presents a supply-insensitive low-power quadrature local oscillation (LO) generator based on the current-reused voltage-controlled oscillator (VCO) and divide-by-two frequency divider (FD). By utilizing the mutual power-supply rejection (M-PSR) technique, a voltage regulator is embedded into the FD to provide a supply-insensitive voltage for VCO. Meanwhile, the feedback loop provides a supply-insensitive current and time constant compensation for FD. The M-PSR technique does not require extra voltage headroom, thus the proposed quadrature LO generator can work under the supply of 0.9 V. A prototype of the proposed quadrature LO generator is implemented in a 28-nm CMOS process. Measurement results indicate that the LO generator achieves a phase noise of −110.5 dBc/Hz@1MHz at the carrier of 5.9 GHz and the power consumption is 1.8 mW. This work has a competitive figure of merit in supply sensitivity or in area (FOMss or FOMa respectively) among the state-of-the-art works.
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- 2021
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29. Sea spray aerosol as a unique source of ice nucleating particles
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DeMott, Paul J, Hill, Thomas CJ, McCluskey, Christina S, Prather, Kimberly A, Collins, Douglas B, Sullivan, Ryan C, Ruppel, Matthew J, Mason, Ryan H, Irish, Victoria E, Lee, Taehyoung, Hwang, Chung Yeon, Rhee, Tae Siek, Snider, Jefferson R, McMeeking, Gavin R, Dhaniyala, Suresh, Lewis, Ernie R, Wentzell, Jeremy JB, Abbatt, Jonathan, Lee, Christopher, Sultana, Camille M, Ault, Andrew P, Axson, Jessica L, Martinez, Myrelis Diaz, Venero, Ingrid, Santos-Figueroa, Gilmarie, Stokes, M Dale, Deane, Grant B, Mayol-Bracero, Olga L, Grassian, Vicki H, Bertram, Timothy H, Bertram, Allan K, Moffett, Bruce F, and Franc, Gary D
- Subjects
Climate Action ,Life Below Water ,marine aerosols ,ice nucleation ,clouds - Abstract
Ice nucleating particles (INPs) are vital for ice initiation in, and precipitation from, mixed-phase clouds. A source of INPs from oceans within sea spray aerosol (SSA) emissions has been suggested in previous studies but remained unconfirmed. Here, we show that INPs are emitted using real wave breaking in a laboratory flume to produce SSA. The number concentrations of INPs from laboratory-generated SSA, when normalized to typical total aerosol number concentrations in the marine boundary layer, agree well with measurements from diverse regions over the oceans. Data in the present study are also in accord with previously published INP measurements made over remote ocean regions. INP number concentrations active within liquid water droplets increase exponentially in number with a decrease in temperature below 0 °C, averaging an order of magnitude increase per 5 °C interval. The plausibility of a strong increase in SSA INP emissions in association with phytoplankton blooms is also shown in laboratory simulations. Nevertheless, INP number concentrations, or active site densities approximated using "dry" geometric SSA surface areas, are a few orders of magnitude lower than corresponding concentrations or site densities in the surface boundary layer over continental regions. These findings have important implications for cloud radiative forcing and precipitation within low-level and midlevel marine clouds unaffected by continental INP sources, such as may occur over the Southern Ocean.
- Published
- 2016
30. Rare prints that survived the turmoil of history and wars – selected collections of the Main Library of the Medical University of Gdańsk
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Małgorzata Florianowicz, Małgorzata Gorczewska, and Bartłomiej Siek
- Subjects
medical university of gdańsk ,gdańsk medical academy ,akademia lekarska in gdańsk ,main library of the gdańsk medical academy ,library of the akademia lekarska in gdańsk ,medical libraries ,medical books ,old books ,Bibliography. Library science. Information resources - Abstract
The collections of the Main Library of the Medical University of Gdańsk both chronologically and in terms of content go beyond the University’s existence and exceed the area of medical topics. The three main components of the historical collections are the prints that came from Vilnius, the acquired post-German collections and the gifts that went to the Library as part of international aid. Apart from typical library documents, the evidence of modernising medical education, such as films on the treatment of selected diseases, is also noteworthy. The paper will present the most interesting items from MUG’s Library collections in the context of the history of books and libraries.
- Published
- 2020
- Full Text
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31. The [S ii] Spectral Images of the Planetary Nebula NGC 7009. II. Major Axis
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Siek Hyung, Seong-Jae Lee, and Masaaki Otsuka
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Planetary nebulae ,H II regions ,Interstellar medium ,Post-asymptotic giant branch ,Astrophysics ,QB460-466 - Abstract
We derived position–velocity density distribution diagrams along the major (PA = 77°) axis of the elliptical planetary nebula NGC 7009 with the Keck HIRES [S ii ] 6716/6731 Å doublet spectral images. The average densities of the main shell and knots of NGC 7009 derived from the [S ii ] 6716/6731 Å fluxes integrated over the line of sight indicate a density range of N _e = 10 ^3.4 to 10 ^3.9 cm ^−3 , while the local densities from the volume fraction resolved in radial velocities along the line of sight show a considerably large range of about 10 ^2.8 –10 ^4.7 cm ^−3 . The derived projection angle of the major axis of the main shell is ψ ∼ 18.3° (±2°). Assuming that the main shell is an ellipsoidal shell with a ≃ 16″ and b ≃ 6″, we found the range of the expansion velocity, radius, and latitude of four knots and a hot bubble. The four knots at points in symmetrical positions are roughly aligned with the same axis of expansion of latitudes ϕ ∼ ±34.5° (±0.6°): one pair expands at about 35 km s ^−1 close to the main ellipsoidal shell, and the other expands rapidly at about 60 km s ^−1 at a distance of r ∼ 16″. In the latitude range ϕ = 65°–75°, the hot bubble of a relatively large structure expands rapidly with a velocity of 130–150 km s ^−1 . The four knots and hot bubble points, which expand faster than the main shell, appear to have been formed by two to three eruptions at a different epoch from the primary structure formation.
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- 2023
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32. Transcriptomic landscape of blood platelets in healthy donors
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Supernat, Anna, Popęda, Marta, Pastuszak, Krzysztof, Best, Myron G., Grešner, Peter, Veld, Sjors In ’t, Siek, Bartłomiej, Bednarz-Knoll, Natalia, Rondina, Matthew T., Stokowy, Tomasz, Wurdinger, Thomas, Jassem, Jacek, and Żaczek, Anna J.
- Published
- 2021
- Full Text
- View/download PDF
33. Identification of a PadR-type regulator essential for intracellular pathogenesis of Burkholderia pseudomallei
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McMillan, Ian A., Norris, Michael H., Zarzycki-Siek, Jan, Heacock-Kang, Yun, Sun, Zhenxin, Borlee, Bradley R., and Hoang, Tung T.
- Published
- 2021
- Full Text
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34. The Burkholderia pseudomallei intracellular ‘TRANSITome’
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Heacock-Kang, Yun, McMillan, Ian A., Norris, Michael H., Sun, Zhenxin, Zarzycki-Siek, Jan, Bluhm, Andrew P., Cabanas, Darlene, Norton, Robert E., Ketheesan, Natkunam, Miller, Jeff F., Schweizer, Herbert P., and Hoang, Tung T.
- Published
- 2021
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35. Acute hypersensitivity pneumonitis in woodworkers caused by inhalation of birch dust contaminated with Pantoea agglomerans and Microbacterium barkeri
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Barbara Mackiewicz, Jacek Dutkiewicz, Jan Siwiec, Tomasz Kucharczyk, Elżbieta Siek, Angelina Wójcik-Fatla, Grażyna Cholewa, Alicja Cholewa, Mariola Paściak, Krzysztof Pawlik, Bogumiła Szponar, and Janusz Milanowski
- Subjects
hypersensitivity pneumonitis ,wood dust ,bacteria ,pantoea agglomerans ,microbacterium barkeri ,inhalation challenge ,occupational exposure ,Agriculture ,Environmental sciences ,GE1-350 - Abstract
Case description Five workers (2 males and 3 females) employed in a furniture factory located in eastern Poland developed hypersensitivity pneumonitis (HP) after the pine wood used for furniture production was replaced by birch wood. All of them reported onset of respiratory and general symptoms (cough, shortness of breath, general malaise) after inhalation exposure to birch dust, showed crackles at auscultation, ground-glass attenuations in HRCT examination, and lymphocytosis in the BAL examination. The diagnosis of acute HP was set in 4 persons and the diagnosis of subacute HP in one. Identification of specific allergen Samples of birch wood associated with evoking disease symptoms were subjected to microbiological analysis with the conventional and molecular methods. Two bacterial isolates were found to occur in large quantities (of the order 10 8 CFU/g) in examined samples: Gram-negative bacterium of the species Pantoea agglomerans and a non-filamentous Gram-positive actinobacterium of the species Microbacterium barkeri . In the test for inhibition of leukocyte migration, 4 out of 5 examined patients showed a positive reaction in the presence of P. agglomerans and 2 in the presence of M. barkeri . Only one person showed the presence of precipitins to P. agglomerans and none to M. barkeri . In the inhalation challenge, which is the most relevant allergological test in the HP diagnostics, all patients reacted positively to P. agglomerans and only one to M. barkeri . The results indicate that P. agglomerans developing in birch wood was the main agent causing HP in the workers exposed to the inhalation of dust from this wood, while the etiologic role of M. barkeri is probably secondary. Conclusion The results demonstrate that apart from fungi and filamentous actinobacteria, regarded until recently as causative agents of HP in woodworkers, Gram-negative bacteria and non-filamentous actinobacteria may also elicit disease symptoms in the workers processing wood infected with large amounts of these microorganisms. The results obtained also seem to indicate that cellular-mediated reactions are more significant for causing disease symptoms compared to those that are precipitin-mediated.
- Published
- 2019
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36. A 12-bit branching time-to-digital converter with power saving features and digital based resolution tuning for PVT variations
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Teh, Jian Sen and Siek, Liter
- Published
- 2020
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37. Concentric liquid reactors for chemical synthesis and separation
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Cybulski, Olgierd, Dygas, Miroslaw, Mikulak-Klucznik, Barbara, Siek, Marta, Klucznik, Tomasz, Choi, Seong Yeol, Mitchell, Robert J., Sobolev, Yaroslav I., and Grzybowski, Bartosz A.
- Published
- 2020
- Full Text
- View/download PDF
38. A Differential Diagnosis of Osteolytic Lesions in the Curated Skeletal Remains of a Tantalus Monkey (Chlorocebus tantalus)
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Siek, Thomas, Hirst, Cara S., and Waldron, Tony
- Published
- 2020
- Full Text
- View/download PDF
39. Targeted crystallization of mixed-charge nanoparticles in lysosomes induces selective death of cancer cells
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Borkowska, Magdalena, Siek, Marta, Kolygina, Diana V., Sobolev, Yaroslav I., Lach, Slawomir, Kumar, Sumit, Cho, Yoon-Kyoung, Kandere-Grzybowska, Kristiana, and Grzybowski, Bartosz A.
- Published
- 2020
- Full Text
- View/download PDF
40. Honeycomb sterna: an unusual case of a developmental abnormality in the sternum
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Hirst, Cara Stella, White, S., Siek, T., and Gasparik, A.
- Published
- 2020
- Full Text
- View/download PDF
41. Exploring an Alternative Material of Holy Book Stand Holder through Malaysian Muslim Perspectives on the Design of Rehal
- Author
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Xiao Hao Gu and Hwee Ling Siek
- Subjects
rehal ,ceramic ,Malaysian Muslims ,design ,General Works - Abstract
The existing holy book stand holder (rehal) made from wood or plastic is a product commonly used by Muslims. Its purpose is to hold and preserve the sanctity of the holy book during recitation. For this study, the researcher formed an understanding of the meaning and cultural value of the rehal from a Malaysian Muslim’s perspective. The materials used to make rehals, their optimum height, as well as acceptable colours, designs, and ornamentations were all analysed. The data collected serves as a guideline by integrating craftsmanship, eco-friendly materials, and relevant design ornaments to create new ceramic rehals that can provide a comfortable user experience.
- Published
- 2022
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42. Chronic maxillary sinusitis in palaeopathology: A review of methods.
- Author
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Lee, Matthew James, Siek, Thomas J., and Hirst, Cara Stella
- Abstract
This study reviews the palaeopathological literature discussing maxillary sinusitis to examine current trends and issues within the study of this condition, and to make recommendations for future research in this area. Seventy-five studies were identified through a literature search of digital and physical sources. Information regarding study metadata, the populations investigated, sinusitis diagnostic criteria, and sinusitis prevalence was examined. Populations from the UK and Europe were the most studied, reflecting both palaeopathology's systemic colonialism and academic legacies. Most studies used diagnostic criteria published in the mid‐1990s, with some subsequent studies modifying these criteria. The diagnostic criteria from 1995 are widely used but do not include all possible bone changes seen within sinusitis. There is also a need for researchers to engage in issues of data reductionism when using descriptive categories for archaeological sites and populations. This paper provides considerations as to how the 1995 diagnostic criteria may be revised by future researchers and synthesises much of the published sinusitis prevalence data to assist researchers interested in the palaeopathology of respiratory disease. More general osteological research, which includes palaeopathological information, was likely missed from this review due to the choice of key terms and languages used in the literature search. Additional research into sinusitis in archaeological populations outside of Western Europe is required. Further work examining the ability to compare pathological data from macroscopic observation and medical imaging would be advantageous to palaeopathology as a whole. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
43. Strategies for Teaching Diversity, Equity, and Inclusion in Principles of Nursing.
- Author
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Victor, Joyce, Gangaware, Ashley, and Siek, Jacob
- Abstract
Background: Nursing programs need to identify creative teaching strategies, guiding students to reflect on individual value systems and consider the values of others as they apply diversity, equity, and inclusion (DEI) in the provision of individualized nursing care. Purpose: The purpose of this project was to develop teaching strategies related to DEI content and examine how first clinical semester, prelicensure baccalaureate nursing students perceived these strategies. Methods: Participants engaged in self-reflection on topics related to DEI, using guided questions in discussion boards, a written paper, and a simulation-based experience. Thirteen students completed an anonymous survey with consideration of these activities and their perceived impact on DEI in their personal nursing practice. Outcomes: Three investigators analyzed survey responses by employing Word Clouds, word counts, and interdependent content analysis and found that using the existing syllabi for the Principles of Nursing course and modifying it to address DEI concepts resulted in perceived increases in awareness, sensitivity, knowledge, competence, and holism. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Epicardial adipose tissue and right ventricular dysfunction in patients with acute pulmonary embolism
- Author
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Grzegorz Staśkiewicz, Piotr Piech, Elżbieta Siek, Piotr Przybylski, Jacek Baj, Piotr Olechowski, Ryszard Maciejewski, Elżbieta Czekajska-Chehab, and Andrzej Drop
- Subjects
epicardial adipose tissue ,right ventricular dysfunction ,pulmonary embolism ,Education ,Sports ,GV557-1198.995 ,Medicine - Abstract
Epicardial adipose tissue has been linked with increased cardiovascular morbidity. Its correlation with right ventriclar morphology and physiology is a recent concept. The aim of the study was to analyze severity of right ventricular dysfunction in the course of acute pulmonary embolism with the amount of epicardial adipose tissue. Retrospective analsis of 192 computed tomography studies with confirmed pulmonary embolism was performed. Patients were divided into two groups with low and high amount of epicardial adipose tissue. Although no significant differences of BMI and severity of pulmonary embolism were observed between the groups, in patients with high amount of epicardial fat, right ventricular dysfunction was significantly more severe.
- Published
- 2019
- Full Text
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45. Digital Dilemma 2018: Digital Presentations in Biological Anthropology and Bioarchaeology
- Author
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Lisa Monetti, Michael B C Rivera, Rachael M Carew, Suzanna White, and Thomas J Siek
- Subjects
Digital Presentation Methods ,Diversity ,Demographics ,Conference Attendance ,Archaeology ,CC1-960 - Abstract
In academia, funding for conference attendance is limited, and both students and early-career researchers are therefore only able to attend a limited number of conferences. This means that, typically, researchers need to choose between attending multiple local and, at times, more affordable conferences, or one or two large, expensive, international conferences. Local and less expensive conferences may be research-specific but will have a smaller audience and lower networking potential. In biological anthropology and bioarchaeology, the majority of these larger annual conferences are held in North America and Western Europe where travel and accommodation costs can be very high for those outside of these regions. These costs, in addition to visa restrictions, reduce the diversity of participants at academic conferences, skewing attendance to students and researchers from the host countries. Not only does this disadvantage individuals outside of the typical host-countries, but it also limits the breadth of academic dialogue, with inclusion in academic conferences determined all too often by financial resources rather than academic value. This paper discusses the demographics and lack of diversity at some of these large conferences and the factors that are known to limit international conference travel. It then presents the benefits of digital presentation methods using Digital Dilemma 2018 as a case study for how digital presentation methods can be combined with physical presentations at minimal cost and time. We hope that this will encourage more conferences to offer a digital presentation option in the future.
- Published
- 2020
- Full Text
- View/download PDF
46. Successful treatment of disseminated fungal abscess-type lesions in the brain and lungs in the course of aspergillosis in a kidney transplant recipient.
- Author
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Bętkowska-Prokop, Alina, Krzanowski, Marcin, Siek, Katarzyna, Sączek, Anna, Rudnicki, Wojciech, and Krzanowska, Katarzyna
- Published
- 2024
- Full Text
- View/download PDF
47. Gdańska ordynacja dla fizyków miejskich z 1661 roku
- Author
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Katarzyna Pękacka-Falkowska and Bartłomiej Siek
- Subjects
XVII w. ,Prusy Królewskie ,ordynacje medyczne ,medycyna miejska ,policja medyczna (Medizinische Polizey) ,History (General) and history of Europe - Abstract
Lekarze miejscy, zwani fizykami, pełnili w Europie nowożytnej szereg funkcji, różniący się w zależności od kraju i regionu. W dziejach medycyny gdańskiej ich rola nie jest jeszcze dokładnie opisana, ze względu na zniszczenia wojenne, które uszczupliły bazę źródłową. Artykuł prezentuje zakres praw i obowiązków fizyków gdańskich w XVII wieku w świetle nieznanego wcześniejszym badaczom źródła – ordynacji miejskiej z 1661 roku.
- Published
- 2020
- Full Text
- View/download PDF
48. The heritable natural competency trait of Burkholderia pseudomallei in other Burkholderia species through comE and crp
- Author
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Yun Heacock-Kang, Ian A. McMillan, Jan Zarzycki-Siek, Zhenxin Sun, Andrew P. Bluhm, Darlene Cabanas, and Tung T. Hoang
- Subjects
Medicine ,Science - Abstract
Abstract Natural competency requires uptake of exogenous DNA from the environment and the integration of that DNA into recipient bacteria can be used for DNA-repair or genetic diversification. The Burkholderia genus is unique in that only some of the species and strains are naturally competent. We identified and characterized two genes, comE and crp, from naturally competent B. pseudomallei 1026b that play a role in DNA uptake and catabolism. Single-copies of rhamnose-inducible comE and crp genes were integrated into a Tn7 attachment-site in non-naturally competent Burkholderia including pathogens B. pseudomallei K96243, B. cenocepacia K56-2, and B. mallei ATCC23344. Strains expressing comE or crp were assayed for their ability to uptake and catabolize DNA. ComE and Crp allowed non-naturally competent Burkholderia species to catabolize DNA, uptake exogenous gfp DNA and express GFP. Furthermore, we used synthetic comE and crp to expand the utility of the λ-red recombineering system for genetic manipulation of non-competent Burkholderia species. A newly constructed vector, pKaKa4, was used to mutate the aspartate semialdehyde dehydrogenase (asd) gene in four B. mallei strains, leading to the complete attenuation of these tier-1 select-agents. These strains have been excluded from select-agent regulations and will be of great interest to the field.
- Published
- 2018
- Full Text
- View/download PDF
49. N III Bowen Lines and Fluorescence Mechanism in the Symbiotic Star AG Peg
- Author
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Siek Hyung, Seong-Jae Lee, and Kang Hwan Lee
- Subjects
symbiotic nova AG Peg ,line profile ,N III Bowen line ,spectroscopic observation ,Astronomy ,QB1-991 - Abstract
We have investigated the intensities and full width at half maximum (FWHM) of the high dispersion spectroscopic N III emission lines of AG Peg, observed with the Hamilton Echelle Spectrograph (HES) in three different epochs at Mt. Hamilton’s Lick Observatory. The earlier theoretical Bowen line study assumed the continuum fluorescence effect, presenting a large discrepancy with the present data. Hence, we analyzed the observed N III lines assuming line fluorescence as the only suitable source: (1) The O III and N III resonance line profiles near λ 374 were decomposed, using the Gaussian function, and the contributions from various O III line components were determined. (2) Based on the theoretical resonant N III intensities, the expected N III Bowen intensities were obtained to fit the observed values. Our study shows that the incoming line photon number ratio must be considered to balance at each N III Bowen line level in the ultraviolet radiation according to the observed lines in the optical zone. We also found that the average FWHM of the N III Bowen lines was about 5 km·s-1 greater than that of the O III Bowen lines, perhaps due to the inherently different kinematic characteristics of their emission zones.
- Published
- 2018
- Full Text
- View/download PDF
50. Mechanisms of Tebuconazole Adsorption in Profiles of Mineral Soils
- Author
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Marcin Siek, Tadeusz Paszko, Maria Jerzykiewicz, Joanna Matysiak, and Urszula Wojcieszek
- Subjects
tebuconazole ,adsorption ,organic matter fractions ,soil acidity ,FT-IR ,Organic chemistry ,QD241-441 - Abstract
The study attempted to identify the soil components and the principal adsorption mechanisms that bind tebuconazole in mineral soils. The KF values of the Freundlich isotherm determined in 18 soils from six soil profiles in batch experiments after 96 h of shaking ranged from 1.11 to 16.85 μg1−1/n (mL)1/n g−1, and the exponent 1/n values from 0.74 to 1.04. The adsorption of tebuconazole was inversely correlated with the soil pH. Both neutral and protonated forms of this organic base were adsorbed mainly on the fraction of humins. The adsorption of the protonated form increased in the presence of hydrogen cations adsorbed in the soil sorption sites. Fourier transform infrared spectroscopy coupled with the molecular modeling studies and partial least squares regression analysis indicated that the tebuconazole molecule is bound in the organic matter through the formation of hydrogen bonds as well as hydrophobic and π–π interactions. Ion exchange was one of the adsorption mechanisms of the protonated form of this fungicide. The created mathematical model, assuming that both forms of tebuconazole are adsorbed on the organic matter and adsorption of the protonated form is affected by the potential acidity, described its adsorption in soils well.
- Published
- 2021
- Full Text
- View/download PDF
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