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- ItemNew investigations at Kalambo Falls, Zambia: Luminescence chronology, site formation, and archaeological significance(Amsterdam [u.a.] : Elsevier, 2015) Duller, Geoff A. T.; Tooth, Stephen; Barham, Lawrence; Tsukamoto, SumikoFluvial deposits can provide excellent archives of early hominin activity but may be complex to interpret, especially without extensive geochronology. The Stone Age site of Kalambo Falls, northern Zambia, has yielded a rich artefact record from dominantly fluvial deposits, but its significance has been restricted by uncertainties over site formation processes and a limited chronology. Our new investigations in the centre of the Kalambo Basin have used luminescence to provide a chronology and have provided key insights into the geomorphological and sedimentological processes involved in site formation. Excavations reveal a complex assemblage of channel and floodplain deposits. Single grain quartz optically stimulated luminescence (OSL) measurements provide the most accurate age estimates for the youngest sediments, but in older deposits the OSL signal from some grains is saturated. A different luminescence signal from quartz, thermally transferred OSL (TT-OSL), can date these older deposits. OSL and TT-OSL results are combined to provide a chronology for the site. Ages indicate four phases of punctuated deposition by the dominantly laterally migrating and vertically aggrading Kalambo River (∼500-300 ka, ∼300-50 ka, ∼50-30 ka, ∼1.5-0.49 ka), followed by deep incision and renewed lateral migration at a lower topographic level. A conceptual model for site formation provides the basis for improved interpretation of the generation, preservation, and visibility of the Kalambo archaeological record. This model highlights the important role of intrinsic meander dynamics in site formation and does not necessarily require complex interpretations that invoke periodic blocking of the Kalambo River, as has previously been suggested. The oldest luminescence ages place the Mode 2/3 transition between ∼500 and 300 ka, consistent with other African and Asian sites where a similar transition can be found. The study approach adopted here can potentially be applied to other fluvial Stone Age sites throughout Africa and beyond.
- ItemCan the effect of cold physical plasma-derived oxidants be transported via thiol group oxidation?(Amsterdam [u.a.] : Elsevier, 2019) Heusler, Thea; Bruno, Giuliana; Bekeschus, Sander; Lackmann, Jan-Wilm; Woedtke, Thomas von; Wende, KristianPurpose: Intra- and intercellular redox-signaling processes where found responsible in various physiological and pathological processes with cellular thiol groups as important signal transducers. Using cold atmospheric plasma (CAP), a similar oxidation pattern of thiol groups can be achieved. Hence, it must be clarified which role extracellular thiol groups play in mediating CAP effects and whether or not the effects of short-lived reactive species can be preserved in a molecule like cysteine. Methods: Physiological buffer solutions containing the amino acid cysteine were treated by an MHz argon plasma jet with molecular gas admixtures (kINPen) and transferred to cultured human keratinocytes. Cell proliferation, migratory activity, and metabolism were investigated. High-resolution mass spectrometry was used to estimate the impact of plasma generated species on thiol groups. Results: While treated physiologic cysteine concentrations showed no impact on cell behavior, artificially high concentrations decreased proliferation, migration and lactate secretion. GSH levels inside cells were stabilized. Conclusion: Extracellular thiol groups scavenge plasma-generated species and form a multitude of covalent modifications. Unexpectedly, human keratinocytes show only small functional consequences for treated physiologic cysteine concentrations. Results for high concentrated cysteine solutions indicate an improved cytostatic/cytotoxic impact by plasma treatment suggesting a potential application as a “preserving agent” of the chemical energy of plasma-derived species. © 2019 The Authors
- ItemFirst insights on plasma orthodontics - Application of cold atmospheric pressure plasma to enhance the bond strength of orthodontic brackets(Amsterdam [u.a.] : Elsevier, 2016) Metelmann, Philine H.; Quooß, Alexandra; Woedtke, Thomas von; Krey, Karl-FriedrichObjective: The development of an ideal adhesive system has long been subject of research. Recent studies show that treatment with cold atmospheric pressure plasma (CAP) positively affects the bonding properties of enamel. Conditioning with CAP could therefore improve the mechanical and physical properties of bracket adhesives, e.g. Glass ionomer cement (GIC). Material and methods: Laser-structured brackets (Dentaurum, Ispringen) were bonded onto 60 bovine mandibular incisors using different orthodontic adhesives. For 20 specimens FujiOrthoLC (GC America Corp, Alsip, USA) was used according to manufacturer's instructions. Another 20 specimens received a 60 s CAP-treatment (kINPen med, Neoplas tool, Greifswald, Germany) before bracket bonding, of which 10 were re-moistened before applying FujiOrthoLC and 10 remained dry. Onto 20 specimens, brackets were bonded with the Composite Transbond XT (3M/Unitek, St. Paul, USA) following manufacturer's instructions. The shear bond strength of brackets on the teeth was determined with the universal testing machine Zwick BZ050/TH3A (Zwick, Ulm, Germany). Results: Brackets bonded with FujiOrthoLC in standard method, showed average shear bond strength of 5.58±0.46 MPa. Specimens treated with plasma showed clinically unacceptable adhesion values (re-moistened group: 2.79±0.38 MPa, dry group: 1.01±0.2 MPa). Bonding onto dried out teeth also led to spontaneous bracket losses (4 of 10 specimens). The composite group (Transbond XT) showed clinically acceptable adhesion values (7.9±1.03 MPa). Conclusions: Despite promising potential, surface conditioning with CAP could not improve the adhesive properties of GIC. By contrast, a decrease in shear bond strength was noticed after CAP treatment. Further investigations have to show whether it is possible to increase the retention values of other orthodontic adhesives by CAP application and thus take advantage of positive characteristics and reduce side effects.
- ItemCold physical plasma-induced oxidation of cysteine yields reactive sulfur species (RSS)(Amsterdam [u.a.] : Elsevier, 2019) Bruno, Giuliana; Heusler, Thea; Lackmann, Jan-Wilm; Woedtke, Thomas von; Weltmann, Klaus-Dieter; Wende, KristianPurpose: Studying plasma liquid chemistry can reveal insights into their biomedical effects, i.e. to understand the direct and indirect processes triggered by the treatment in a model or clinical application. Due to the reactivity of the sulfur atom, thiols are potential targets for plasma- derived reactive species. Being crucial for protein function and redox signaling pathways, their controllable modification would allow expanding the application range. Additionally, models to control and standardize CAP sources are desired tools for plasma source design. Methods: Cysteine, a ubiquitous amino acid, was used as a tracer compound to scavenge the reactive species produced by an argon plasma jet (kINPen). The resulting product pattern was identified via high-resolution mass spectrometry. The Ellman´s assay was used to screen CAP derived thiol consumption, and long-lived species deposition (hydrogen peroxide, nitrite, nitrate) was monitored in relation to the presence of cysteine. Results: The intensity of cysteine oxidation increased with treatment time and availability of oxygen in the feed gas. A range of products from cysteine was identified, in part indicative for certain treatment conditions. Several non-stable products occur transiently during the plasma treatment. Bioactive reactive sulfur species (RSS) have been found for mild treatment conditions, such as cysteine sulfoxides and cysteine-S-sulfonate. Considering the number of cysteine molecules in the boundary layer and the achieved oxidation state, short-lived species dominate in cysteine conversion. In addition, a boundary layer depletion of the tracer was observed. Conclusion: Translating these data into the in-vivo application, strong direct oxidation of protein thiol groups with subsequent changes in protein biochemistry must be considered. Plasma-derived RSS may in part contribute to the observed biomedical effects of CAP. Care must be taken to control the discharge parameter tightly as chemical dynamics at or in the liquid are subject to change easily. © 2019
- ItemIntegrating data and analysis technologies within leading environmental research infrastructures: Challenges and approaches(Amsterdam [u.a.] : Elsevier, 2021) Huber, Robert; D'Onofrio, Claudio; Devaraju, Anusuriya; Klump, Jens; Loescher, Henry W.; Kindermann, Stephan; Guru, Siddeswara; Grant, Mark; Morris, Beryl; Wyborn, Lesley; Evans, Ben; Goldfarb, Doron; Genazzio, Melissa A.; Ren, Xiaoli; Magagna, Barbara; Thiemann, Hannes; Stocker, MarkusWhen researchers analyze data, it typically requires significant effort in data preparation to make the data analysis ready. This often involves cleaning, pre-processing, harmonizing, or integrating data from one or multiple sources and placing them into a computational environment in a form suitable for analysis. Research infrastructures and their data repositories host data and make them available to researchers, but rarely offer a computational environment for data analysis. Published data are often persistently identified, but such identifiers resolve onto landing pages that must be (manually) navigated to identify how data are accessed. This navigation is typically challenging or impossible for machines. This paper surveys existing approaches for improving environmental data access to facilitate more rapid data analyses in computational environments, and thus contribute to a more seamless integration of data and analysis. By analysing current state-of-the-art approaches and solutions being implemented by world‑leading environmental research infrastructures, we highlight the existing practices to interface data repositories with computational environments and the challenges moving forward. We found that while the level of standardization has improved during recent years, it still is challenging for machines to discover and access data based on persistent identifiers. This is problematic in regard to the emerging requirements for FAIR (Findable, Accessible, Interoperable, and Reusable) data, in general, and problematic for seamless integration of data and analysis, in particular. There are a number of promising approaches that would improve the state-of-the-art. A key approach presented here involves software libraries that streamline reading data and metadata into computational environments. We describe this approach in detail for two research infrastructures. We argue that the development and maintenance of specialized libraries for each RI and a range of programming languages used in data analysis does not scale well. Based on this observation, we propose a set of established standards and web practices that, if implemented by environmental research infrastructures, will enable the development of RI and programming language independent software libraries with much reduced effort required for library implementation and maintenance as well as considerably lower learning requirements on users. To catalyse such advancement, we propose a roadmap and key action points for technology harmonization among RIs that we argue will build the foundation for efficient and effective integration of data and analysis.
- ItemEffectiveness of myAirCoach: A mHealth Self-Management System in Asthma(Amsterdam [u.a.] : Elsevier, 2020) Khusial, Rishi J.; Honkoop, Persijn J.; Usmani, Omar; Soares, Marcia; Simpson, Andrew; Biddiscombe, Martyn; Meah, Sally; Bonini, Matteo; Lalas, Antonios; Polychronidou, Eleftheria; Koopmans, Julia G.; Moustakas, Konstantinos; Snoeck-Stroband, Jiska B.; Ortmann, Steffen; Votis, Konstantinos; Tzovaras, Dimitrios; Chung, Kian Fan; Fowler, Stephen; Sont, Jacob K.Background: Self-management programs have beneficial effects on asthma control, but their implementation in clinical practice is poor. Mobile health (mHealth) could play an important role in enhancing self-management. Objective: To assess the clinical effectiveness and technology acceptance of myAirCoach-supported self-management on top of usual care in patients with asthma using inhalation medication. Methods: Patients were recruited in 2 separate studies. The myAirCoach system consisted of an inhaler adapter, an indoor air-quality monitor, a physical activity tracker, a portable spirometer, a fraction exhaled nitric oxide device, and an app. The primary outcome was asthma control; secondary outcomes were exacerbations, quality of life, and technology acceptance. In study 1, 30 participants were randomized to either usual care or myAirCoach support for 3 to 6 months; in study 2, 12 participants were provided with the myAirCoach system in a 3-month before-after study. Results: In study 1, asthma control improved in the intervention group compared with controls (Asthma Control Questionnaire difference, 0.70; P = .006). A total of 6 exacerbations occurred in the intervention group compared with 12 in the control group (hazard ratio, 0.31; P = .06). Asthma-related quality of life improved (mini Asthma-related Quality of Life Questionnaire difference, 0.53; P = .04), but forced expiratory volume in 1 second was unchanged. In study 2, asthma control improved by 0.86 compared with baseline (P = .007) and quality of life by 0.16 (P = .64). Participants reported positive attitudes toward the system. Discussion: Using the myAirCoach support system improves asthma control and quality of life, with a reduction in severe asthma exacerbations. Well-validated mHealth technologies should therefore be further studied. © 2020 The Authors