scholarly journals Helium Nanodroplet Isolation Spectroscopy in an Undergraduate Teaching Laboratory

2020 ◽  
Author(s):  
Paul Raston
Keyword(s):  
Low Temperature ◽  
Small Molecules ◽  
Undergraduate Students ◽  
Undergraduate Teaching ◽  
Helium Nanodroplets ◽  
Teaching Laboratory ◽  
Undergraduate Chemistry ◽  
Infrared Spectral ◽  
Upper Level ◽  
First Time

<div><p>A home-built helium nanodroplet isolation spectrometer has been utilized by undergraduate students in course-based experiments to investigate the rovibrational dynamics of small molecules. Helium nanodroplets are well known to simplify the spectroscopy of embedded molecules owing to their low temperature (0.4 K) and weakly interacting nature. In the infrared spectral region, this results in a small number of rotationally resolved lines that can often be collected and analyzed in several lab periods. We demonstrate the advantages of using this technique in an upper-level undergraduate chemistry course for which the laser spectroscopy of helium solvated <sup>13</sup>C-labelled formic acid was investigated for the first time.</p></div>

scholarly journals Helium Nanodroplet Isolation Spectroscopy in an Undergraduate Teaching Laboratory

2020 ◽  
Author(s):  
Paul Raston
Keyword(s):  
Low Temperature ◽  
Small Molecules ◽  
Undergraduate Students ◽  
Undergraduate Teaching ◽  
Helium Nanodroplets ◽  
Teaching Laboratory ◽  
Undergraduate Chemistry ◽  
Infrared Spectral ◽  
Upper Level ◽  
First Time

<div><p>A home-built helium nanodroplet isolation spectrometer has been utilized by undergraduate students in course-based experiments to investigate the rovibrational dynamics of small molecules. Helium nanodroplets are well known to simplify the spectroscopy of embedded molecules owing to their low temperature (0.4 K) and weakly interacting nature. In the infrared spectral region, this results in a small number of rotationally resolved lines that can often be collected and analyzed in several lab periods. We demonstrate the advantages of using this technique in an upper-level undergraduate chemistry course for which the laser spectroscopy of helium solvated <sup>13</sup>C-labelled formic acid was investigated for the first time.</p></div>

scholarly journals Helium Nanodroplet Isolation Spectroscopy in an Undergraduate Teaching Laboratory

2020 ◽  
Author(s):  
Paul Raston
Keyword(s):  
Low Temperature ◽  
Small Molecules ◽  
Undergraduate Students ◽  
Undergraduate Teaching ◽  
Helium Nanodroplets ◽  
Teaching Laboratory ◽  
Undergraduate Chemistry ◽  
Infrared Spectral ◽  
Upper Level ◽  
First Time

<div>A home-built helium nanodroplet isolation spectrometer has been utilized by</div><div>undergraduate students in course-based experiments to investigate the rovibrational dynamics</div><div>of small molecules. Helium nanodroplets are well known to simplify the spectroscopy of</div><div>embedded molecules owing to their low temperature (0.4 K) and weakly interacting nature.</div><div>In the infrared spectral region, this results in a small number of rotationally resolved lines that</div><div>can often be collected and analyzed in several lab periods. We demonstrate the advantages of</div><div>using this technique in an upper-level undergraduate chemistry course for which the laser</div><div>spectroscopy of helium solvated 13C-labelled formic acid was investigated for the first time.</div><div><br></div>

scholarly journals Exploratory Research on Curriculum Construction of Medical Metrology Education in Colleges and Universities

2020 ◽  
Vol 10 (11) ◽  
pp. 859-864
Author(s):  
Ze-Dong Yan ◽  
◽  
Wei Guo ◽  
Juan Liu ◽  
Er-Ping Luo ◽  
...  
Keyword(s):  
Undergraduate Students ◽  
Colleges And Universities ◽  
Basic Knowledge ◽  
Exploratory Research ◽  
Cultivation System ◽  
Teaching Laboratory ◽  
National Medical ◽  
Cultivation Mode ◽  
Curriculum Construction ◽  
First Time

Canonical and systematic quality-oriented education of medical metrology for undergraduate students has not been started in colleges and universities. The standardized training and professional cultivation system are also deficient for most medical metrological employees at present. In this study, special funds were invested to develop the teaching laboratory based on the establishment standards of national medical metrology stations. Experienced experts were also invited for the argumentation of curriculum construction and optimization of medical metrology. As a result, two undergraduate courses of medical metrology for the students majoring in Biomedical Engineering (BME) were developed for the first time based on the talent cultivation mode “basic knowledge + practical ability”. An internationally-advanced teaching laboratory for medical metrology was established, and the series textbooks were compiled and published. It is of vital significance to strengthen the curriculum construction of medical metrology for undergraduate students of BME, which may provide beneficial reference for further medical metrological talent cultivation.

scholarly journals Structure of the master regulator Rns reveals an inhibitor of enterotoxigenic Escherichia coli virulence regulons

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charles R. Midgett ◽  
Kacey Marie Talbot ◽  
Jessica L. Day ◽  
George P. Munson ◽  
F. Jon Kull
Keyword(s):  
Escherichia Coli ◽  
Small Molecules ◽  
Family Member ◽  
Shigella Flexneri ◽  
Decanoic Acid ◽  
Enterotoxigenic Escherichia Coli ◽  
Gram Negative Bacteria ◽  
Enteric Infections ◽  
First Time ◽  
Arac Family

AbstractEnteric infections caused by the gram-negative bacteria enterotoxigenic Escherichia coli (ETEC), Vibrio cholerae, Shigella flexneri, and Salmonella enterica are among the most common and affect billions of people each year. These bacteria control expression of virulence factors using a network of transcriptional regulators, some of which are modulated by small molecules as has been shown for ToxT, an AraC family member from V. cholerae. In ETEC the expression of many types of adhesive pili is dependent upon the AraC family member Rns. We present here the 3 Å crystal structure of Rns and show it closely resembles ToxT. Rns crystallized as a dimer via an interface similar to that observed in other dimeric AraC’s. Furthermore, the structure of Rns revealed the presence of a ligand, decanoic acid, that inhibits its activity in a manner similar to the fatty acid mediated inhibition observed for ToxT and the S. enterica homologue HilD. Together, these results support our hypothesis that fatty acids regulate virulence controlling AraC family members in a common manner across a number of enteric pathogens. Furthermore, for the first time this work identifies a small molecule capable of inhibiting the ETEC Rns regulon, providing a basis for development of therapeutics against this deadly human pathogen.

Furil based ionic small molecules for green emitting non-doped LECs with improved color purity

2021 ◽  
Author(s):  
Jino C John ◽  
Kanagaraj Shanmugasundaram ◽  
Archana Puthanveedu ◽  
Hariventhan Ragupathi ◽  
Gopakumar Gopinadhanpillai ◽  
...  
Keyword(s):  
Small Molecules ◽  
Color Purity ◽  
First Time

Two novel furil based small molecules FlBzPy and FlThPy were designed and synthesized with simple synthetic procedures for the first time for the LEC application. The optical, thermal, electronic, electroluminescent,...

Transformation behavior of yttria stabilized tetragonal zirconia polycrystal–TiB2 composites

2001 ◽  
Vol 16 (7) ◽  
pp. 2158-2169 ◽  
Author(s):  
B. Basu ◽  
J. Vleugels ◽  
O. Van Der Biest
Keyword(s):  
Thermal Expansion ◽  
Phase Transformation ◽  
Low Temperature ◽  
Tetragonal Zirconia ◽  
Mechanical Analysis ◽  
Transformation Behavior ◽  
Thermal Expansion Data ◽  
Thermally Induced ◽  
First Time ◽  
Tetragonal Zirconia Polycrystal

The objective of the present article is to study the influence of TiB2 addition on the transformation behavior of yttria stabilized tetragonal zirconia polycrystals (Y-TZP). A range of TZP(Y)–TiB2 composites with different zirconia starting powder grades and TiB2 phase contents (up to 50 vol%) were processed by the hot-pressing route. Thermal expansion data, as obtained by thermo-mechanical analysis were used to assess the ZrO2 phase transformation in the composites. The thermal expansion hysteresis of the transformable ceramics provides information concerning the transformation behavior in the temperature range of the martensitic transformation and the low-temperature degradation. Furthermore, the transformation behavior and susceptibility to low-temperature degradation during thermal cycling were characterized in terms of the overall amount and distribution of the yttria stabilizer, zirconia grain size, possible dissolution of TiB2 phase, and the amount of residual stress generated in the Y-TZP matrix due to the addition of titanium diboride particles. For the first time, it is demonstrated in the present work that the thermally induced phase transformation of tetragonal zirconia in the Y-TZP composites can be controlled by the intentional addition of the monoclinic zirconia particles into the 3Y-TZP matrix.

CO2 hydrogenation into CH4 over Ni–Fe catalysts

2018 ◽  
Vol 11 (03) ◽  
pp. 1850057 ◽  
Author(s):  
Reza Meshkini Far ◽  
Olena V. Ischenko ◽  
Alla G. Dyachenko ◽  
Oleksandr Bieda ◽  
Snezhana V. Gaidai ◽  
...  
Keyword(s):  
Low Temperature ◽  
Synergistic Effect ◽  
Atmospheric Pressure ◽  
High Efficiency ◽  
Co2 Hydrogenation ◽  
Hydrogenation Catalysts ◽  
Fe Catalysts ◽  
First Time ◽  
Supported Ni ◽  
Hydrogenation Of Co

Here, we report, for the first time, on the catalytic hydrogenation of CO2 to methane at atmospheric pressure. For the preparation of hydrogenation catalysts based on Ni and Fe metals, a convenient method is developed. According to this method, low-temperature reduction of the co-precipitated Ni and Fe oxides with hydrogen gives the effective and selective bimetallic Ni[Formula: see text]Fe[Formula: see text], Ni[Formula: see text]Fe[Formula: see text] and Ni[Formula: see text]Fe[Formula: see text] catalysts. At the temperature range of 300–400[Formula: see text]C, they exhibit a high efficiency of CH4 production with respect to monometallic Ni and Fe catalysts. The results imply a synergistic effect between Ni and Fe which caused the superior activity of the Ni[Formula: see text]Fe[Formula: see text] catalyst conversing [Formula: see text]% of CO2 into CH4 at 350[Formula: see text]C. To adapt the Ni–Fe catalysts in the industry, the effect of two different carriers on the efficiency of the alumina-supported Ni[Formula: see text]Fe[Formula: see text] catalyst was investigated. It is found that the Ni[Formula: see text]Fe[Formula: see text]/[Formula: see text]-Al2O3 catalyst effectively conversed CO2 giving 100% methane yield already at 275[Formula: see text]C.

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