Technology Teacher: Navigating by Good Gyrations

This activity describes some simple, yet impressive gyroscopic demonstrations using only a bike wheel with a quick-release hub. Then, itIt explains both the angular momentum principle that tends to keep the wheel in a rigid plane and the effects of the external forces that create precession. And all without a single equation!No equations are used during the activity. Understanding the forces at work on a gyroscope will raise your students' consciousness of all kinds of devices and phenomena, from how and why a football, a rifle, and a Frisbee disk work to how an aircraft or a spacecraft can keep itself on course. Educational levels: Middle school, High school

Technology Teacher: Listening for Rings from Space

This activity introduces gravitational waves and the NASA technology being developed to detect them in space. It involves building a metaphorical interferometer that demonstrates how the mission (and all interferometry) works. Educational levels: Middle school, High school

Results of measurements of PM10 at a kerbside location in Breda, the Netherlands

De gemeente Breda heeft geconstateerd dat de meetwaarden van fijn stof (PM10) bij de Tilburgseweg te Breda hoog zijn in vergelijking met de andere meetpunten van het Landelijk Meetnet Luchtkwaliteit (LML) van het RIVM. Dit is zichtbaar in de lijst met geconstateerde overschrijdingsdagen zoals die continu wordt bijgehouden op de website van het LML. Op verzoek van de gemeente Breda heeft de provincie Noord-Brabant de fijnstofconcentraties in de periode van augustus tot en met oktober 2006 gemeten. In de periode augustus tot en met oktober 2006 heeft het RIVM eveneens fijnstofreferentiemetingen verricht. Uit de referentiemetingen volgt dat de metingen van het RIVM en de provincie Noord-Brabant met elkaar in overeenstemming zijn. De meetresultaten van de automatische metingen zijn in overeenstemming met de in Europa geldende kwaliteitscriteria. Uit het equivalentieonderzoek dat in 2006 door het LML heeft plaatsgevonden, volgt dat het aantal gerapporteerde overschrijdingsdagen van het meetstation aan de Tilburgseweg te Breda is aangepast.The Breda local authority has ascertained a higher concentration of particulate matter on the kerbside of the Tilburgseweg (a road running through Breda) than concentrations measured at other locations across the country. These measurements were performed by the Dutch National Air Monitoring Network of the National Institute for Public Health and the Environment (RIVM), which observed the highest concentrations at a kerbside location in the city itself. On the request of the Breda local authorities, the provincial authorities measured the particulate matter concentrations (PM10) from September till October 2006. In the same period, RIVM's Laboratory for Environmental Monitoring performed measurements on particulate matter (PM10) using reference techniques from the European guideline. According to the reference measurements, the measurements done by RIVM (with uncertainties taken into consideration) and the province of Noord-Brabant turned out to be in agreement. The routine measurements performed were shown to satisfy the European quality criteria for PM10 measurement. Finally, judging from the 2006 validation and equivalence study, it was obvious that the reported number of days in which concentrations were exceeded at the kerbside location of the Tilburgseweg in Breda had been adjusted.Gemeente Bred

HD 40307g

An undated print of planet HD 4307g by the NASA JPL team in a series titled Visions of the Future.https://scholarworks.moreheadstate.edu/university_art_collection/1223/thumbnail.jp

c-di-AMP, a likely master regulator of bacterial K + homeostasis machinery, activates a K + exporter

bis-(3',5')-cyclic diadenosine monophosphate (c-di-AMP) is a second messenger with roles in virulence, cell wall and biofilm formation, and surveillance of DNA integrity in many bacterial species, including pathogens. Strikingly, it has also been proposed to coordinate the activity of the components of K+ homeostasis machinery, inhibiting K+ import, and activating K+ export. However, there is a lack of quantitative evidence supporting the direct functional impact of c-di-AMP on K+ transporters. To gain a detailed understanding of the role of c-di-AMP on the activity of a component of the K+ homeostasis machinery in B. subtilis, we have characterized the impact of c-di-AMP on the functional, biochemical, and physiological properties of KhtTU, a K+/H+ antiporter composed of the membrane protein KhtU and the cytosolic protein KhtT. We have confirmed c-di-AMP binding to KhtT and determined the crystal structure of this complex. We have characterized in vitro the functional properties of KhtTU and KhtU alone and quantified the impact of c-di-AMP and of pH on their activity, demonstrating that c-di-AMP activates KhtTU and that pH increases its sensitivity to this nucleotide. Based on our functional and structural data, we were able to propose a mechanism for the activation of KhtTU by c-di-AMP. In addition, we have analyzed the impact of KhtTU in its native bacterium, providing a physiological context for the regulatory function of c-di-AMP and pH. Overall, we provide unique information that supports the proposal that c-di-AMP is a master regulator of K+ homeostasis machinery.We acknowledge the SOLEIL and ALBA synchrotrons for access and thank their staff for help with data collection. Support of the Biochemical and Biophysical Technologies, Cell Culture and Genotyping and X-ray Crystallography scientific platforms of i3S (Porto, Portugal) is also acknowledged. Mass spectrometry analysis was performed by Hugo Osório at the i3S Proteomics Scientific Platform. This work had support from the Portuguese Mass Spectrometry Network, integrated in the National Roadmap of Research Infrastructures of Strategic Relevance (ROTEIRO/0028/2013; LISBOA-01-0145-FEDER-022125). Work was supported by FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020-Operational Programme for Competitiveness and Internationalization (POCI), Portugal 2020, and by Portuguese funds through FCT - Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior in the framework of the projects POCI-01–0145-FEDER-029863(PTDC/BIABQM/29863/2017) and by Fundação Luso-Americana para o Desenvolvimento through the FLAD Life Science 2020 award ‘Bacterial K+ transporters are potential antimicrobial targets: mechanisms of transport and regulation’

The effect of bacterial growth phase and culture concentration on U(VI) removal from aqueous solution

Bacteria play a key role in controlling the mobility of contaminants, such as uranium (U), in the environment. Uranium could be sourced from disposed radioactive waste, derived either from surface disposal trenches for Low Level Waste (LLW) that, because of the waste type and disposal concept, would typically present acidic conditions or from the geological disposal of LLW or Intermediate Level Waste (ILW) that, because of the waste type and the disposal concept, would typically present alkaline conditions. In disposed radioactive waste, there could be variable amounts of cellulosic material. Bacterial cells may be living in a range of different growth phases, depending on the growth conditions and nutrients available at the time any waste-derived U migrated to the cells. A key knowledge gap to date has been the lack of a mechanistic understanding of how bacterial growth phases (exponential, stationary, and death phase) affect the ability of bacteria to remove U(VI) from solution. To address this, we first characterised the cells using potentiometric titrations to detect any differences in proton binding to proton active sites on Pseudomonas putida cells at each growth phase under aerobic conditions, or under anaerobic conditions favourable to U(IV) reoxidation. We then conducted batch U(VI) removal experiments with bacteria at each phase suspended in 1 and 10 ppm U aqueous solutions with the pH adjusted from 2 to 12 as well as with culture concentrations from 0.01 to 10 g/L, to identify the minimal concentration of bacteria in solution necessary to affect U removal. We found that, in death phase, P. putida cells exhibited double the concentration of proton active sites than bacteria grown to exponential and stationary phase. However, we did not see a difference in the extent of U(VI) removal, from a 10 ppm U solution, between the different growth phases as a function of pH (2 to 12). Culture concentration affected U removal between pH 2–8, where U removal decreased with a decreasing concentration of cells in solution. When the pH was 10–12, ≤55% of U precipitated abiotically. The presence of bacteria in solution (0.01–10 g/L), regardless of growth phase, increased the precipitation of U from ≤55% up to 70–90%, accumulating inside the cells and on the cell walls as ~0.2 μm uranyl phosphate precipitates. These precipitates were also found at low pH with the exception of cells at exponential growth phase. This study demonstrates that growth phase affects the proton-active site concentration but not the extent of U bound to P. putida cells and that growth phase dictates the form of U removed from solution. Since the pH of trench-disposed LLW is controlled by the degradation of cellulosic waste, leading to acidic conditions (pH 4–6), bacterial concentrations would be expected to highly affect the extent of U removed from solution. The cement in grouted ILW and LLW, for geologic disposal, will allow for the development of extremely high pH values in solution (pH 9–13), where even the smallest concentrations of bacteria were able to significantly increase the removal of U from solution under aerobic conditions, or under anaerobic conditions favourable to U(IV) reoxidation

Cell surface acid-base properties of the cyanobacterium Synechococcus: Influences of nitrogen source, growth phase and N:P ratios

The distribution of many trace metals in the oceans is controlled by biological uptake. Recently, Liu et al. (2015) demonstrated the propensity for a marine cyanobacterium to adsorb cadmium from seawater, suggesting that cell surface reactivity might also play an important role in the cycling of metals in the oceans. However, it remains unclear how variations in cyanobacterial growth rates and nutrient supply might affect the chemical properties of their cellular surfaces. In this study we used potentiometric titrations and Fourier Transform Infrared (FT-IR) spectrometry to profile the key metabolic changes and surface chemical responses of a Synechococcus strain, PCC 7002, during different growth regimes. This included testing various nitrogen (N) to phosphorous (P) ratios (both nitrogen and phosphorous dependent), nitrogen sources (nitrate, ammonium and urea) and growth stages (exponential, stationary, and death phase). FT-IR spectroscopy showed that varying the growth substrates on which Synechococcus cells were cultured resulted in differences in either the type or abundance of cellular exudates produced or a change in the cell wall components. Potentiometric titration data were modeled using three distinct proton binding sites, with resulting pKa values for cells of the various growth conditions in the ranges of 4.96-5.51 (pKa1), 6.67-7.42 (pKa2) and 8.13-9.95 (pKa3). According to previous spectroscopic studies, these pKa ranges are consistent with carboxyl, phosphoryl, and amine groups, respectively. Comparisons between the titration data (for the cell surface) and FT-IR spectra (for the average cellular changes) generally indicate (1) that the nitrogen source is a greater determinant of ligand concentration than growth phase, and (2) that phosphorus limitation has a greater impact on Synechococcus cellular and extracellular properties than does nitrogen limitation. Taken together, these techniques indicate that nutritional quality during cell growth can noticeably influence the expression of cell surface ligands and their measurable densities. Given that cell surface charge ultimately affects metal adsorption, our results suggest that the cycling of metals by Synechococcus cells in the oceans may vary regionally

Kepler-16b

An undated print of planet Kepler-16b by the NASA JPL team in a series titled Visions of the Future.https://scholarworks.moreheadstate.edu/university_art_collection/1222/thumbnail.jp

PSO J318.5-22

An undated print of planet PSO J318.5-22 by the NASA JPL team in a series titled Visions of the Future.https://scholarworks.moreheadstate.edu/university_art_collection/1221/thumbnail.jp