Name: uncovering hidden dynamics of natural photonic structures using holographic imaging
Uploaded: 2022-03-31T14:40:00
Description: Watch this Scientific Journal Video about Uncovering Hidden Dynamics of Natural Photonic Structures Using Holographic Imaging at JoVE.com

M. S. P., D. G., D. V., and B. K. acknowledge support of the Biological and bioinspired structures for multispectral surveillance, funded by NATO SPS (NATO Science for Peace and Security) 2019-2022. B. K., D. V., B. B., D. G., and M. S. P. acknowledge funding provided bythe Institute of Physics Belgrade, through the institutional funding bythe Ministry of Education, Science, and Technological Development of theRepublic of Serbia. Additionally, B. K. acknowledges support from F R S - FNRS. M. P. acknowledges support from the Ministry of Education, Science and Technological Development of the Republic of Serbia, Contract number 451-03-9/2021-14/200026. S. R. M. was supported by a BEWARE Fellowship of the Walloon Region (Convention n&#176;2110034), as a postdoctoral researcher. T. V. acknowledges financial support from the Hercules Foundation. D.V., M.S.P., D.G., M.P., B.B., and B.K. acknowledge the support of the Office of Naval Research Global through the Research Grant N62902-22-1-2024.&#160;This study was conducted in partial fulfillment of the requirements for the PhD degree of Marina Simovi&#263; Pavlovi&#263; at the University of Belgrade, Faculty of Mechanical Engineering.

1. Precharacterization
<ol>
	<li>Perform a full precharacterization of the sample.
	<ol>
		<li>Perform all experiments on dry specimens purchased from a commercial source. Store the samples in the laboratory, in a dry and dark place, at room temperature.</li>
		<li>Prior to holographic measurements, perform a complete sample characterization by scanning electronic microscope (SEM), linear optical spectroscopy, and nonlinear optical microscopy (NOM)10 (Figure...

<ol>
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P., Jankovi&#263;, B. &. #. 3. 8. 1. ;. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+transition+from+low+to+high+iodide+and+iodine+state+in+the+Briggs-Rauscher+oscillatory+reaction+containing+malonic+acid+using+Kolmogorov-Johnson-Mehl-Avrami+(KJMA)+theory.">Analysis of transition from low to high iodide and iodine state in the Briggs-Rauscher oscillatory reaction containing malonic acid using Kolmogorov-Johnson-Mehl-Avrami (KJMA) theory.</a> Reaction Kinetics, Mechanisms and Catalysts. 123 (1), 61-80 (2018).</li><li>Mouchet, S. 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P., Tyler, J. M., Tohline, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shifted+Fresnel+diffraction+for+computational+holography.">Shifted Fresnel diffraction for computational holography.</a> Optical Express. 15 (9), 5631-5640 (2007).</li><li>Pavlovi&#263;, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Naturally+safe:+Cellular+noise+for+document+security.">Naturally safe: Cellular noise for document security.</a> Journal of Biophotonics. 12 (12), 201900218 (2019).</li><li>Bray, W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+periodic+reaction+inhomogeneous+solution+and+its+relation+to+catalysis.">A periodic reaction inhomogeneous solution and its relation to catalysis.</a> Journal of the American Chemical Society. 43 (6), 1262-1267 (1921).</li><li>Nicolis, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-organization+in+nonequilibrium+systems.">Self-organization in nonequilibrium systems.</a> Dissipative Structures to Order through Fluctuations. , 339-426 (1977).</li><li>Prigogine, I., Hiebert, E. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=From+being+to+becoming:+Time+and+complexity+in+the+physical+sciences.">From being to becoming: Time and complexity in the physical sciences.</a> Physics Today. 35 (1), 69 (1982).</li><li>Nikolova, L., Ramanujam, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Polarization Holography. , (2009).</li><li>Haisch, C., Kykal, C., Niessner, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photophoretic+velocimetry+for+the+characterization+of+aerosols.">Photophoretic velocimetry for the characterization of aerosols.</a> Analytical Chemistry. 80 (5), 1546-1551 (2008).</li><li>Kononenko, V. 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In the presented biophotonic study, it is shown that a novel holographic method can be used to detect minimal morphological displacement or deformation caused by low-level thermal radiation.
The most critical step in holographic measurement with biological samples is the preparation step. The preparation of the sample (cutting/gluing to match the size of the holder) depends on the sample&#39;s mechanical properties, and it is not possible to have a standard protocol for this step.
<p class...

To fully understand and notice all the unique phenomena in the nanoworld, it is crucial to employ techniques that are capable of revealing all details regarding structures and dynamics at the nanoscale. On this account, the unique combination of linear and nonlinear methods, combined with the power of holography to reveal the system&#39;s dynamics at the nanoscale are presented.
The described holographic technique can be viewed as the triple rec method (rec is the abbreviation for recording), since at a given time the signal is simultaneously recorded by a photographic camera, a thermal camera, and an interferometer. Linear and nonlinear optical spectroscopy and holography are well-known techniques, the fundamental principles of which are extensively described in the literature1,2.
To cut a long story short, holographic interferometry allows the comparison of wavefronts recorded at different moments in time to characterize the dynamics of the system. It was previously used to measure vibrational dynamics3,4. The power of holography as the simplest interferometry method is based on its ability to detect the smallest displacement within the system. First, we exploited holography to observe and reveal the photophoretic effect5 (i.e., the displacement of deformation of a nanostructure due to a light-induced thermal gradient), in different biological structures. For a true presentation of the method, representative samples were selected from a number of tested biological specimens6. Wings of the Queen of Spain fritillary butterfly, Issoria lathonia (Linnaeus, 1758; I. lathonia), were used in the framework of this study.
After having successfully demonstrated the occurrence of photophoresis at the nanoscale in biological tissues, a similar protocol was applied to monitor the spontaneous symmetry breaking process7 caused by a phase transition in an oscillatory chemical reaction. In this part, the phase transition from a low concentration of iodide and iodine (called state I) to a high concentration of iodide and iodine with solid iodine formation (defined as state II) that occurs in a chemically nonlinear BR reaction was studied8,9. Here, we reported for the first time a holographic approach that allows studying such a phase transition and spontaneous symmetry breaking dynamics at the nanoscale occurring in condensed systems.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Active Vibration Isolation, Four Optical Table Supports</td>
			<td>Thorlabs</td>
			<td>PTR502</td>
			<td>High Load Capacity: 2,500 kg, Height 600 mm</td>
		</tr>
		<tr>
			<td>Cuvette</td>
			<td></td>
			<td></td>
			<td>Standard glass cuvette</td>
		</tr>
		<tr>
			<td>Holographic camera (optical camera for holography)</td>
			<td>Cannon</td>
			<td>EOS 50D</td>
			<td>Sensor Size 22.3 x 14.9 mm; Pixel pitch 4.69 &#181;m; Max. resolution 4752 x 3168; JPEG file format</td>
		</tr>
		<tr>
			<td>Hydrogen peroxide, H2O2</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Laser</td>
			<td>Laser Quantum</td>
			<td>Torus 532 laser</td>
			<td>Wavelength 532 nm; Power 390 mW; Coherence length 10 m</td>
		</tr>
		<tr>
			<td>LED lasers</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Malonic acid, C3H4O4</td>
			<td>Acr<img alt="Equation 10" src="/files/ftp_upload/63676/63676eq10.png" />s Organics (Geel, Belgium)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Manganese sulphate,&#160; MnSO4</td>
			<td>Fluka (Buchs, Switzerlend)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nonlinear optical microscope</td>
			<td>IPB</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Optical accessories</td>
			<td>Thorlab</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Optical spectroscope</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Optical table</td>
			<td>Thorlabs</td>
			<td>TOP450II PTR52509</td>
			<td>dimensions 2000*1250*310 mm</td>
		</tr>
		<tr>
			<td>Perchloric acid, HClO4</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium iodate, KIO3</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Software</td>
			<td></td>
			<td></td>
			<td>Home-build software made by one of the authors: Dusan Grujic. This software was conducted in partial fulfillment of the requirements for the PhD deegree of D.G.</td>
		</tr>
		<tr>
			<td>Thermal camera</td>
			<td>Flir</td>
			<td>A65</td>
			<td>640x512 pixel; Thermal resolution 50 mK</td>
		</tr>
		<tr>
			<td>Video camera</td>
			<td>Nikon</td>
			<td>1v3</td>
			<td>18.4 Mpixel; 60 fps</td>
		</tr>
	</tbody>
</table>

uncovering hidden dynamics of natural photonic structures using holographic imaging

In this method, the potential of optics and holography to uncover hidden details of a natural system's dynamical response at the nanoscale is exploited. In the first part, the optical and holographic studies of natural photonic structures are presented as well as conditions for the appearance of the photophoretic effect, namely, the displacement or deformation of a nanostructure due to a light-induced thermal gradient, at the nanoscale. This effect is revealed by real-time digital holographic interferometry monitoring the deformation of scales covering the wings of insects induced by temperature. The link between geometry and nanocorrugation that leads to the emergence of the photophoretic effect is experimentally demonstrated and confirmed. In the second part, it is shown how holography can be potentially used to uncover hidden details in the chemical system with nonlinear dynamics, such as the phase transition phenomenon that occurs in complex oscillatory Briggs-Rauscher (BR) reaction. The presented potential of holography at the nanoscale could open enormous possibilities for controlling and molding the photophoretic effect and pattern formation for various applications such as particle trapping and levitation, including the movement of unburnt hydrocarbons in the atmosphere and separation of different aerosols, decomposition of microplastics and fractionation of particles in general, and assessment of temperature and thermal conductivity of micron-size fuel particles.

A photophoretic effect was induced and monitored in a first experiment on the wing of a Morpho menelaus butterfly5. The effect was initiated by the action of LED lasers of different wavelengths (450 nm, 532 nm, 660 nm, and 980 nm). Here, the wings from an I. lathonia butterfly14 were used. After the recording procedure, the hologram image was reconstructed.
<img alt="Figure 3" class="xf...

Watch this Scientific Journal Video about Uncovering Hidden Dynamics of Natural Photonic Structures Using Holographic Imaging at JoVE.com

Uncovering Hidden Dynamics of Natural Photonic Structures Using Holographic Imaging

The paper is primarily focused on the combined power of optical (linear and nonlinear) and holographic methods used to reveal phenomena at the nanoscale. The results obtained from the biophotonic and oscillatory chemical reactions' studies are given as representative examples, highlighting holography's ability to reveal dynamics at a nanoscale.

In this method, the potential of optics and holography to uncover hidden details of a natural system's dynamical response at the nanoscale is exploited. ...

This is the first time, to the best of our knowledge, that holographic technique was used to monitor photo for races in insect twins and face transition in non-equilibrium conditions. The advantage of this non-invasive technique lies in the fact, that it does not cause any significant disturbance to the system. This is of high importance, for instance, for non-equilibrium studies.Nonlinear optics and holography provide insight in complex organized structures that we encounter in all scientific disciplines. These are non-destructive techniques able to interrogate such structures on a submicron scale. Knowledge of wave and geometric optics is necessary to prepare the setup, while the analysis is based on the knowledge of physics, the experiment itself, it's simpler to perform.Since the presented experiments are perform incomplete darkness, the opportunity to follow visual signature has critical importance for the described study To begin, perform a complete sample characterization by scanning electron microscope, linear optical spectroscopy, and non-linear optical microscopy. After adjusting the room temperature, turn on the laser and check the alignment of the optical elements. Then, align the laser beam perfectly with the concave mirror.Afterward, check and adjust the position of the optical beam expander. Next, determine the beam part that impinges on the sample, and ensure that it forms a reflex beam. Check if the rest of the beam is collected on a spherical mirror to be used to generate the reference beam.And also, the detector is placed within the interference zone of the two specified beams. Set up an optical photographic camera for the holographic experiment. And another one to view visible changes in the Briggs-Rauscher reaction.Additionally, set a thermal camera with a thermal resolution of 50 milli Kelvins, and a focal length of 13 millimeters. To prepare the sample for chemical reaction monitoring, place support with a flat adhesive surface on the optical table upon which the cuvette, or vessel will be placed. Then, fill the reactants into the cuvette, and mix in the cuvette, having different volumes and concentrations, ensuring that the total volume in the cuvette is 2.5 milliliters.Next, place it on the support in the setup. After switching off the external lights, synchronize the cameras by using a chosen interval. Then, press the recording buttons and induce dynamical changes in the system of interest.Next, observe the holographic experiment. Then, pronounce the end of the process and save the results. To check the probe hologram for appropriate settings, choose one hologram and make a reconstruction by clicking on the reconstruct button.Afterward, change the settings to achieve the best image, and make the reconstruction again, while repeating the steps until the best settings are defined. To perform the reconstructions, choose all the holograms and apply the desired parameters for numerical reconstruction of holograms. Then, carry out the reconstructions using the reconstruct button and the interferogram by inserting the file names in the Start with/End with field, and then, by clicking the button, Batch.Perform a visual analysis by looking for visible changes in the interference pattern. And try to match the changes in the interference pattern with results obtained by optical and thermal measurements. Next, perform a cross examination by thoroughly analyzing the images visually from both the optical and thermal cameras with the holographic reconstructions in order to reveal dynamics at the Nano scale.In the case of the B.R reaction, the analysis of interferograms, reveals a change in the fringe pattern at the exact moment of a phase transition. The results are of particular importance, as the optical interferometric method does not cause any significant disturbance to the system, which is a vital importance for the non-equilibrium studies. Additionally, the holographic reconstruction was performed for Wings of Butterfly, Azoria Lithonia, irradiated by lasers light at 450, 532, and 980 nanometers.The results clearly show, that the interaction of nano structures with light, generates displacement at the Nano scale within the tissues, that affect the interferometric pattern. This presented technique, opens the possibility to reveal various dynamics and self-assembly processes for the different systems at the nano and meso scale.

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Protein conformation and dynamics are key to understanding the relationship between protein structure and function. Hydrogen exchange coupled with high-resolution mass spectrometry is a versatile method to study the conformational dynamics of proteins as well as characterizing protein-ligand and protein-protein interactions, including contact interfaces and allosteric effects.

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In nature, complex functional structures are formed by the self-assembly of biomolecules under mild conditions. Understanding the forces that control ...

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Nanoparticles, as one of the key materials in nanotechnology and nanomedicine, have gained significant importance during the past decade. While ...

Laboratory Production of Biofuels and Biochemicals from a Rapeseed Oil through Catalytic Cracking Conversion

The work is based on a reported study which investigates the processability of canola oil (bio-feed) in the presence of bitumen-derived heavy gas oil (HGO) for production of transportation fuels through a fluid catalytic cracking (FCC) route. Cracking experiments are performed with a fully automated reaction unit at a fixed weight hourly space velocity (WHSV) of 8 hr-1, 490-530 &#176;C, and catalyst/oil ratios of 4-12 g/g. When a feed is in contact with catalyst in the fluid-bed reactor, cracking takes place generating gaseous, liquid, and solid products. The vapor produced is condensed and collected in a liquid receiver at -15 &#176;C. The non-condensable effluent is first directed to a vessel and is sent, after homogenization, to an on-line gas chromatograph (GC) for refinery gas analysis. The coke deposited on the catalyst is determined in situ by burning the spent catalyst in air at high temperatures. Levels of CO2 are measured quantitatively via an infrared (IR) cell, and are converted to coke yield. Liquid samples in the receivers are analyzed by GC for simulated distillation to determine the amounts in different boiling ranges, i.e., IBP-221 &#176;C (gasoline), 221-343 &#176;C (light cycle oil), and 343 &#176;C+ (heavy cycle oil). Cracking of a feed containing canola oil generates water, which appears at the bottom of a liquid receiver and on its inner wall. Recovery of water on the wall is achieved through washing with methanol followed by Karl Fischer titration for water content. Basic results reported include conversion (the portion of the feed converted to gas and liquid product with a boiling point below 221 &#176;C, coke, and water, if present) and yields of dry gas (H2-C2's, CO, and CO2), liquefied petroleum gas (C3-C4), gasoline, light cycle oil, heavy cycle oil, coke, and water, if present.

This paper presents an experimental method to produce biofuels and biochemicals from canola oil mixed with a fossil-based feed in the presence of a catalyst at mild temperatures. Gaseous, liquid, and solid products from a reaction unit are quantified and characterized. Conversion and individual product yields are calculated and reported.

The work is based on a reported study which investigates the processability of canola oil (bio-feed) in the presence of bitumen-derived heavy gas oil ...

Fabrication and Testing of Photonic Thermometers

In recent years, a push for developing novel silicon photonic devices for telecommunications has generated a vast knowledge base that is now being leveraged for developing sophisticated photonic sensors. Silicon photonic sensors seek to exploit the strong confinement of light in nano-waveguides to transduce changes in physical state to changes in resonance frequency. In the case of thermometry, the thermo-optic coefficient, i.e., changes in refractive index due to temperature, causes the resonant frequency of the photonic device such as a Bragg grating to drift with temperature. We are developing a suite of photonic devices that leverage recent advances in telecom compatible light sources to fabricate cost-effective photonic temperature sensors, which can be deployed in a wide variety of settings ranging from controlled laboratory conditions, to the noisy environment of a factory floor or a residence. In this manuscript, we detail our protocol for the fabrication and testing of photonic thermometers.

We describe the process of fabrication and testing of photonic thermometers.

In recent years, a push for developing novel silicon photonic devices for telecommunications has generated a vast knowledge base that is now being ...

Aerosol-assisted Chemical Vapor Deposition of Metal Oxide Structures: Zinc Oxide Rods

Whilst columnar zinc oxide (ZnO) structures in the form of rods or wires have been synthesized previously by different liquid- or vapor-phase routes, their high cost production and/or incompatibility with microfabrication technologies, due to the use of pre-deposited catalyst-seeds and/or high processing temperatures exceeding 900 &#176;C, represent a drawback for a widespread use of these methods. Here, however, we report the synthesis of ZnO rods via a non-catalyzed vapor-solid mechanism enabled by using an aerosol-assisted chemical vapor deposition (CVD) method at 400 &#176;C with zinc chloride (ZnCl2) as the precursor and ethanol as the carrier solvent. This method provides both single-step formation of ZnO rods and the possibility of their direct integration with various substrate types, including silicon, silicon-based micromachined platforms, quartz, or high heat resistant polymers. This potentially facilitates the use of this method at a large-scale, due to its compatibility with state-of-the-art microfabrication processes for device manufacture. This report also describes the properties of these structures (e.g., morphology, crystalline phase, optical band gap, chemical composition, electrical resistance) and validates its gas sensing functionality towards carbon monoxide.

Columnar zinc oxide structures in the form of rods are synthesized via aerosol-assisted chemical vapor deposition without the use of pre-deposited catalyst-seed particles. This method is scalable and compatible with various substrates based on either silicon, quartz or polymers.

Whilst columnar zinc oxide (ZnO) structures in the form of rods or wires have been synthesized previously by different liquid- or vapor-phase routes, ...

Minimum Burning Pressures of Water-based Emulsion Explosives

This manuscript describes a protocol to measure the minimum pressure required for sustained burning of water-based emulsion explosives. Pumping water-based emulsion explosives for blasting applications can be very hazardous, as demonstrated by a number of pump accidents around the globe in the last decades, including some that resulted in fatalities. In Canada, the recognition of this hazard has led to the development of pumping guidelines that were endorsed by both the explosives industry and the Explosive Regulatory Division of the Canadian government. In these guidelines, it was noted that the minimum burning pressures (MBP) measured in a laboratory would provide a good guide to characterize the behaviour of these products in pumping systems. The same guidelines also call for the design of pump systems that prevent, whenever possible, pressures from exceeding the MBP of the product being pumped. At the time of publication of these guidelines, a methodology existed for measuring such MBP values but it had never been validated to measure the MBP of ammonium nitrate water-based emulsions (AWEs). AWEs are now used much more widely than any other water-based explosives and precursors in on-site bulk loading operations.
The Canadian Explosives Research Laboratory (CanmetCERL) has been conducting research over the last ten years to develop a validated testing protocol to measure and interpret representative MBP values for AWEs. The test, as it is performed today, will be described and the critical components will be justified by reference to recent published data. Results of MBP measurements, for a range of AWE products, will be presented. Inclusion of the MBP test in the test standards for the authorization of high explosives in Canada will also be discussed.

We present an apparatus based on hot-wire ignition in a pressurized enclosure and an associated methodology to measure the minimum pressure required to induce sustained combustion in water-based emulsion explosives. This method improves product characterization to allow one to use them more safely during pumping and mixing operations.

This manuscript describes a protocol to measure the minimum pressure required for sustained burning of water-based emulsion explosives. Pumping ...

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals

We discuss in this article the experimental measurements of the molecules in liquid crystal (LC) phase using the time-resolved infrared (IR) vibrational spectroscopy and time-resolved electron diffraction. Liquid crystal phase is an important state of matter that exists between the solid and liquid phases and it is common in natural systems as well as in organic electronics. Liquid crystals are orientationally ordered but loosely packed, and therefore, the internal conformations and alignments of the molecular components of LCs can be modified by external stimuli. Although advanced time-resolved diffraction techniques have revealed picosecond-scale molecular dynamics of single crystals and polycrystals, direct observations of packing structures and ultrafast dynamics of soft materials have been hampered by blurry diffraction patterns. Here, we report time-resolved IR vibrational spectroscopy and electron diffractometry to acquire ultrafast snapshots of a columnar LC material bearing a photoactive core moiety. Differential-detection analyses of the combination of time-resolved IR vibrational spectroscopy and electron diffraction are powerful tools for characterizing structures and photoinduced dynamics of soft materials.

Here, we present the protocols of differential-detection analyses of time-resolved infrared vibrational spectroscopy and electron diffraction which enable observations of the deformations of local structures around photoexcited molecules in a columnar liquid crystal, giving an atomic perspective on the relationship between the structure and the dynamics of this photoactive material.

We discuss in this article the experimental measurements of the molecules in liquid crystal (LC) phase using the time-resolved infrared (IR) vibrational ...

Employing Pressurized Hot Water Extraction (PHWE) to Explore Natural Products Chemistry in the Undergraduate Laboratory

A recently developed pressurized hot water extraction (PHWE) method which utilizes an unmodified household espresso machine to facilitate natural products research has also found applications as an effective teaching tool. Specifically, this technique has been used to introduce second- and third-year undergraduates to aspects of natural products chemistry in the laboratory. In this report, two experiments are presented: the PHWE of eugenol and acetyleugenol from cloves and the PHWE of seselin and (+)-epoxysuberosin from the endemic Australian plant species Correa reflexa. By employing PHWE in these experiments, the crude clove extract, enriched in eugenol and acetyleugenol, was obtained in 4-9% w/w from cloves by second-year undergraduates and seselin and (+)-epoxysuberosin were isolated in yields of up to 1.1% w/w and 0.9% w/w from C. reflexa by third-year students. The former exercise was developed as a replacement for the traditional steam distillation experiment providing an introduction to extraction and separation techniques, while the latter activity featured guided-inquiry teaching methods in an effort to simulate natural products bioprospecting. This primarily derives from the rapid nature of this PHWE technique relative to traditional extraction methods that are often incompatible with the time constraints associated with undergraduate laboratory experiments. This rapid and practical PHWE method can be used to efficiently isolate various classes of organic molecules from a range of plant species. The complementary nature of this technique relative to more traditional methods has also been demonstrated previously.

Employing Pressurized Hot Water Extraction PHWE to Explore Natural Products Chemistry in the Undergraduate Laboratory

Here, we employ a pressurized hot water extraction (PHWE) method, which utilizes an unmodified household espresso machine to introduce undergraduates to natural products chemistry in the laboratory. Two experiments are presented: PHWE of eugenol and acetyleugenol from cloves and PHWE of seselin and (+)-epoxysuberosin from the Australian plant Correa reflexa.

A recently developed pressurized hot water extraction (PHWE) method which utilizes an unmodified household espresso machine to facilitate natural products ...

DNA Origami-Mediated Substrate Nanopatterning of Inorganic Structures for Sensing Applications

Structural DNA nanotechnology provides a viable route for building from the bottom-up using DNA as construction material. The most common DNA nanofabrication technique is called DNA origami, and it allows high-throughput synthesis of accurate and highly versatile structures with nanometer-level precision. Here, it is shown how the spatial information of DNA origami can be transferred to metallic nanostructures by combining the bottom-up DNA origami with the conventionally used top-down lithography approaches. This allows fabrication of billions of tiny nanostructures in one step onto selected substrates. The method is demonstrated using bowtie DNA origami to create metallic bowtie-shaped antenna structures on silicon nitride or sapphire substrates. The method relies on the selective growth of a silicon oxide layer on top of the origami deposition substrate, thus resulting in a patterning mask for following lithographic steps. These nanostructure-equipped surfaces can be further used as molecular sensors (e.g., surface-enhanced Raman spectroscopy (SERS)) and in various other optical applications at the visible wavelength range owing to the small feature sizes (sub-10 nm). The technique can be extended to other materials through methodological modifications; therefore, the resulting optically active surfaces may find use in development of metamaterials and metasurfaces.

Here, we describe a protocol to create discrete and accurate inorganic nanostructures on substrates using DNA origami shapes as guiding templates. The method is demonstrated by creating plasmonic gold bowtie-shaped antennas on a transparent substrate (sapphire).