This research was funded by the Austrian Science Fund (FWF): P23681-B16.

1. Preparation of Plant Materials
<ol>
	<li>Use either leaves or whole plants of subject plant material (Hosta spp. or Phaseolus vulgaris).</li>
</ol>
2. Preparation of Water Solutions Containing Ice Nucleation Active (INA) Bacteria
<ol>
	<li>Culture the INA bacterium, Pseudomonas syringae (Strain Cit-7) in petri dishes at 25 &#176;C on Pseudomonas Agar F prepared with 10 g/L of 100% glycerol per the manufacturer&#8217;s direction.</li>
	<li>After cultures have grown sufficiently, place at 4 &#176;C until needed but keep at 4 &#176;C for two days prior to ensure a high level of ice nucleation activity.</li>
	<li>Scrape bacteria from a single plate from the surface of the agar with a plastic, disposable or re-usable metal spatula at the time of use and place in 10-15 ml of deionized water in a 25 ml disposable cuvette. The concentration should be in the range of 1 x 107 to 1 x 109 &#183; ml -1. The solution will appear cloudy. There is no need to confirm the concentration using a hemocytometer or spectrophotometer, as concentration need only be approximate.</li>
	<li>Vortex the cuvette for a minimum of 10 sec to distribute the bacteria. 
	Note: The specific concentration of the resulting INA mixture is not important and the protocol described will provide more than an adequate level of ice nucleation activity. This mixture of INA bacteria and water will be used later in the nucleation experiments.</li>
</ol>
3. Setting Up a Freezing Experiment
<ol>
	<li>Place the high resolution infrared camera (SC-660) inside the protective acrylic box so that the lens projects through the opening in the front of the box and the wires connecting the camera to a laptop or recording device exit through the rear opening of the box. Secure the lid of the box and place the box inside the environmental chamber or freezer in a location that will allow the subject plant material to be seen.
	<ol>
		<li>Provide a dark background around the plant material by lining the walls of the chamber with black construction paper to prevent interference from reflected infrared energy.</li>
		<li>Fit the chamber with LED lighting to minimize heating from the light source when recording images in visible wavelengths is required. Only a minimum of lighting, such as a battery-operated closet light or other small LED device, is required for the plants to be visible by the camera.
		<ol>
			<li>Once visible images of the subject plant material are taken, turn off the LED lighting. Distribute all external wired connections (firewire connection to computer, power cord, etc.) to the camera via a port or other opening in the chamber.</li>
		</ol>
		</li>
		<li>Fill any extra space in the port or opening with insulating foam material to avoid or reduce temperature gradients within the chamber. Set the initial temperature of the chamber at 1 &#176;C.</li>
	</ol>
	</li>
	<li>Align plants or plant parts so that the plant material is in the field-of-view of the camera and the plant material is visible on the remote viewing screen or within the chosen software.</li>
	<li>Allow plants to equilibrate at 1 &#176;C for 30 min to 1 hr, depending on the size of the plant material, prior to initiating a controlled freezing experiment. This ensures that the temperature of the plant will not lag behind air temperature by many degrees once the freezing experiment is initiated. Equilibration is achieved when the temperature of the plant material is within 0.5 &#176;C of air temperature.
	<ol>
		<li>Place a layer of Styrofoam insulation on top of the soil of potted plants if potted plants are used. Once the plants have equilibrated, commence cooling of the chamber. 
		Note: The layer of insulation on the soil surface of the pot reduces the amount of continued heat loss from the pot to the air surrounding the plant, and prevents the roots from freezing, as this would not typically occur during a frost event in nature due to the massive reservoir of residual heat present in the soil.</li>
	</ol>
	</li>
	<li>Set the desired camera parameters (color palette, temperature range, specific areas of interest, etc.), as discussed in 3.4.1-3.4.4.
	<ol>
		<li>Select the rainbow palette to display the temperature variations while viewing the live image.</li>
		<li>Set the temperature span to 5 &#176;C by adjusting the temperature bar located just below the image in the software.</li>
		<li>Choose the linear scale (algorithm) for converting the infrared data into the false color image as defined by the selected palette (rainbow) and set the range of temperature to 5 &#176;C and to track automatically based on the image. Alternatively, adjust the set range manually while conducting the experiment.
		<ol>
			<li>Use the temperature of a specific point or an average temperature within the defined area of interest provided by the software. Retrieve the temperature data of all pixels from the recorded video sequence or from the information embedded in the image file. Figure 3 shows a typical screenshot from within ResearchIR software.</li>
		</ol>
		</li>
		<li>Place a cursor on a location on the plant tissue that represents a specific point of interest. Define the area of interest as points (1 -3 pixels in size), boxes, lines, ellipses, or circles. Multiple combinations of points or shapes can be located over the image.</li>
	</ol>
	</li>
	<li>Recording a video sequence
	<ol>
		<li>Set the camera to record at 60 Hz and for the recording to be stopped manually.</li>
		<li>Indicate the location on the computer or external drive where the recorded video file will be placed.</li>
		<li>Commence recording. 
		Note: Recording to an external hard drive is highly recommended since large video files will be generated. Recorded video files can be later edited to contain only the portion containing the necessary information. This will greatly reduce the file size.</li>
		<li>Lower the temperature of the chamber incrementally by 0.5 -1.0 &#176;C. Wait until the plant temperature equilibrates with air temperature and then lower the temperature again by 0.5-1.0 &#176;C. Depending on the mass of the plant tissue being observed and its morphology, equilibration can take 10 to 15 min. Thus, giving a cooling rate of about 4 &#176;C/hr.</li>
		<li>Continue in this manner until the plant freezes and observations are completed. End the recording when the freezing process has been completed. 
		Note: The plant tissue has equilibrated with air temperature when the plant material and background are the same color since they are at the same temperature. Since the background temperature and the temperature of the plant tissue are the same, it may be difficult to visualize the plant material until you again lower the temperature and there is temperature differential between the plant tissue and air temperature.</li>
	</ol>
	</li>
</ol>

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The authors have no competing financial interests or conflicts of interest.

Water has the ability to supercool to temperatures well below 0 &#176;C and the temperature at which water will freeze can be quite variable.36 The temperature limit for supercooling of pure water is about -40 &#176;C and is defined as the homogeneous nucleation point. When water freezes at temperatures warmer than -40 &#176;C it is brought about by the presence of heterogenous nucleators that enable small ice embryos to form which then serve as a catalyst for ice formation and growth.37 There are a...

Freezing temperatures that occur when plants are actively growing can be lethal, particularly if the plant has little or no freezing tolerance. Such frost events often have devastating effects on agricultural production and can also play an important role in shaping community structure in natural populations of plants, especially in alpine, sub-arctic and arctic ecosystems 1-6. Episodes of severe spring frosts have had major impacts on fruit production in the USA and South America in recent years 7-9 and have been exacerbated by the early onset of warm weather followed by more typical mean low temperatures. The early warm weather induces buds to break, activating the growth of new shoots, leaves, and flowers all of which have very little to no frost tolerance 1,3,10-12. Such erratic weather patterns have been reported to be a direct reflection of ongoing climate change and are expected to be a common weather pattern for the foreseeable future 13. Efforts to provide economical, effective, and environmentally-friendly management techniques or agrochemicals that can provide increased frost tolerance have had limited success for a host of reasons but this can be partly attributed to the complex nature of freezing tolerance and freezing avoidance mechanisms in plants. 14
The adaptive mechanisms associated with frost survival in plants have traditionally been divided into two categories, freezing tolerance and freezing avoidance. The former category is associated with biochemical mechanisms regulated by a specific set of genes that allow plants to tolerate the stresses associated with the presence and the dehydrative effect of ice in its tissues. While the latter category is typically, but not solely, associated with structural aspects of a plant that determine if, when, and where ice forms in a plant 14. Despite the prevalence of freeze avoidance as an adaptive mechanism, little research has been devoted in recent times to understanding the underlying mechanisms and regulation of freeze avoidance. The reader is referred to a recent review 15 for greater details on this subject.
While the formation of ice at low temperatures may seem like a simple process, many factors contribute to determining the temperature at which ice nucleates in plant tissues and how it spreads within the plant. Parameters such as the presence of extrinsic and intrinsic ice nucleators, heterogeneous vs. homogeneous nucleation events, thermal-hysteresis (antifreeze) proteins, the presence of specific sugars and other osmolytes, and a host of structural aspects of the plant can all play a significant role in the freezing process in plants. Collectively, these parameters influence the temperature at which a plant freezes, where ice is initiated and how it grows. They can also affect the morphology of the resulting ice crystals. Various methods have been used to study the freezing process in plants under laboratory conditions, including nuclear magnetic resonance spectroscopy (NMR) 16, magnetic resonance imaging (MRI) 17, cryo-microscopy 18-19, and low-temperature scanning electron microscopy (LTSEM). 20 Freezing of whole plants in laboratory and field settings, however, has mainly been monitored with thermocouples. The use of thermocouples to study freezing is based on the liberation of heat (enthalpy of fusion) when water undergoes a phase transition from a liquid to a solid. Freezing is then recorded as an exothermic event. 21-23 Even though thermocouples are the typical method of choice in studying freezing in plants, their use has many limitations that limit the amount of information obtained during a freezing event. For instance, with thermocouples it is difficult to nearly impossible to determine where ice is initiated in plants, how it propagates, if it propagates at an even rate, and if some tissues remain free of ice.
Advances in high-resolution infrared thermography (HRIT) 24-27, however, have significantly increased the ability to obtain information about the freezing process in whole plants, especially when used in a differential imaging mode. 28-33 In the present report, we describe the use of this technology to study various aspects of the freezing process and various parameters that affect where and and at what temperature ice is initiated in plants. A protocol will be presented that will demonstrate the ability of the ice-nucleation-active (INA) bacterium, Pseudomonas syringae (Cit-7) to act as an extrinsic nucleator initiating freezing in a herbaceous plant at a high, subzero temperature.
High-resolution Infrared Camera
The protocol and examples documented in this report utilize a high resolution infrared video radiometer. The radiometer (Figure 1) supplies a combination of infrared and visible spectrum images and temperature data. The spectral response of the camera is in the range of 7.5 to 13.5 &#181;m and provides 640 x 480 pixel resolution. Visible spectrum images generated by the built-in camera can be fused with IR-images in real time, which facilitates the interpretation of complex, thermal images. A range of lenses for the camera can be used to make close-up and microscopic observations. The camera can be used in a stand-alone mode, or interfaced and controlled with a laptop using propietary software. The software can be used to obtain a variety of thermal data embedded in the recorded videos. It is important to note that a wide variety of infrared radiometers are commercially available. Therefore, it is essential that the researcher discuss their intended application with a knowledgeable product engineer and that the researcher test the ability of any specific radiometer to provide the information needed. The imaging radiometer used in the described protocol is placed in an acrylic box (Figure 2) insulated with Styrofoam in order to deter exposure to condensation during the warming and cooling protocols. This protection is not needed for all cameras or applications.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Infrared Camera</td>
			<td>FLIR</td>
			<td>SC-660</td>
			<td>Many models available depending on application</td>
		</tr>
		<tr>
			<td>Infrared Analytical Software</td>
			<td>FLIR</td>
			<td>ResearchIR 4.10.2.5</td>
			<td align="right">$3,500</td>
		</tr>
		<tr>
			<td rowspan="2">Pseudomonas syringae (strain Cit-7)</td>
			<td rowspan="2"></td>
			<td rowspan="2"></td>
			<td rowspan="2"><a href="mailto:icelab@berkeley.edu">Kindly provided by Dr. Steven Lindow, University of California&#160; Berkeley icelab@berkeley.edu</a></td>
		</tr>
		<tr>
		</tr>
		<tr>
			<td>Pseudomonas Agar F</td>
			<td>Fisher Scientific</td>
			<td>DF0448-17-1</td>
			<td></td>
		</tr>
	</tbody>
</table>

the use of high-resolution infrared thermography (hrit) for the study of ice nucleation and ice propagation in plants

Freezing events that occur when plants are actively growing can be a lethal event, particularly if the plant has no freezing tolerance. Such frost events often have devastating effects on agricultural production and can also play an important role in shaping community structure in natural populations of plants, especially in alpine, sub-arctic, and arctic ecosystems. Therefore, a better understanding of the freezing process in plants can play an important role in the development of methods of frost protection and understanding mechanisms of freeze avoidance. Here, we describe a protocol to visualize the freezing process in plants using high-resolution infrared thermography (HRIT). The use of this technology allows one to determine the primary sites of ice formation in plants, how ice propagates, and the presence of ice barriers. Furthermore, it allows one to examine the role of extrinsic and intrinsic nucleators in determining the temperature at which plants freeze and evaluate the ability of various compounds to either affect the freezing process or increase freezing tolerance. The use of HRIT allows one to visualize the many adaptations that have evolved in plants, which directly or indirectly impact the freezing process and ultimately enables plants to survive frost events.

Ice-nucleating activity of the Ice+ bacterium, Pseudomonas syringae (strain Cit-7)
A 10 &#181;l drop of water and 10 &#181;l of water containing P. syringae (Cit-7) were placed on the abaxial surface of a Hosta leaf (Hosta spp.) (Figure 4). As illustrated, the drop of water containing the INA bacteria froze first and was responsible for inducing the leaf to freeze while the drop of water on the leaf surface remained unfrozen.
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Watch this Scientific Journal Video about The Use of High-resolution Infrared Thermography HRIT for the Study of Ice Nucleation and Ice Propagation in Plants at JoVE.com

The Use of High-resolution Infrared Thermography HRIT for the Study of Ice Nucleation and Ice Propagation in Plants

Here we present a protocol that allows one to visualize sites of ice formation and avenues of ice propagation in plants utilizing high resolution infrared thermography (HRIT).

The Use of High-resolution Infrared Thermography (HRIT) for the Study of Ice Nucleation and Ice Propagation in Plants

Freezing events that occur when plants are actively growing can be a lethal event, particularly if the plant has no freezing tolerance. Such frost events ...

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9.5K Views.  Agricultural Research Service (USDA-ARS), Kearneysville, WV. Here we present a protocol that allows one to visualize sites of ice formation and avenues of ice propagation in plants utilizing high resolution infrared thermography (HRIT).

Video: The Use of High-resolution Infrared Thermography HRIT for the Study of Ice Nucleation and Ice Propagation in Plants

Expression of Recombinant Cellulase Cel5A from Trichoderma reesei in Tobacco Plants

Cellulose degrading enzymes, cellulases, are targets of both research and industrial interests. The preponderance of these enzymes in difficult-to-culture organisms, such as hyphae-building fungi and anaerobic bacteria, has hastened the use of recombinant technologies in this field. Plant expression methods are a desirable system for large-scale production of enzymes and other industrially useful proteins. Herein, methods for the transient expression of a fungal endoglucanase, Trichoderma reesei Cel5A, in Nicotiana tabacum are demonstrated. Successful protein expression is shown, monitored by fluorescence using an mCherry-enzyme fusion protein. Additionally, a set of basic tests are used to examine the activity of transiently expressed T. reesei Cel5A, including SDS-PAGE, Western blotting, zymography, as well as&#160;fluorescence and dye-based substrate degradation assays. The system described here can be used to produce an active cellulase in a short time period, so as to assess the potential for further production in plants through constitutive or inducible expression systems.

Expression of Recombinant Cellulase Cel5A from Trichoderma reesei in Tobacco Plants

Tobacco plants were used to produce a fungal cellulase, TrCel5A, via a transient expression system. The expression could be monitored using a fluorescent fusion protein, and the protein activity was characterized post-expression.

Cellulose degrading enzymes, cellulases, are targets of both research and industrial interests. The preponderance of these enzymes in difficult-to-culture ...

Enhancement of the Initial Growth Rate of Agricultural Plants by Using Static Magnetic Fields

Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing seeds of Garden Balsam (Impatiens balsamina), Mizuna (Brassica rapa var. japonica), Komatsuna (Brassica rapa var. perviridis), and Mescluns (Lepidium sativum). We applied magnets under the culture dish. During the 4 days of application, we observed that the stem and root length increased. The group subjected to magnetic field treatment (n = 10) showed a 1.4 times faster rate of growth compared with the control group (n = 11) in a total of 8 days (p &#60;0.0005). This rate is 20% higher than that reported in previous studies. The tubulin complex lines did not have connecting points, but connecting points occur upon the application of magnets. This shows complete difference from the control, which means abnormal arrangements. However, the exact cause remains unclear. These results of growth enhancement of applying magnets suggest that it is possible to enhance the growth rate, increase productivity, or control the speed of germination of plants by applying static magnetic fields. Also, magnetic fields can cause physiological changes in plant cells and can induce growth. Therefore, stimulation with a magnetic field can have possible effects that are similar to those of chemical fertilizers, which means that the use of fertilizers can be avoided.

The goal of this protocol is to demonstrate the acceleration of the initial growth rate of plants by applying static magnetic fields with no external energy.

Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing ...

Use of a Battery of Chemical and Ecotoxicological Methods for the Assessment of the Efficacy of Wastewater Treatment Processes to Remove Estrogenic Potency

Endocrine Disrupting Compounds pose a substantial risk to the aquatic environment. Ethinylestradiol (EE2) and estrone (E1) have recently been included in a watch list of environmental pollutants under the European Water Framework Directive. Municipal wastewater treatment plants are major contributors to the estrogenic potency of surface waters. Much of the estrogenic potency of wastewater treatment plant (WWTP) effluents can be attributed to the discharge of steroid estrogens including estradiol (E2), EE2 and E1 due to incomplete removal of these substances at the treatment plant. An evaluation of the efficacy of wastewater treatment processes requires the quantitative determination of individual substances most often undertaken using chemical analysis methods. Most frequently used methods include Gas Chromatography-Mass Spectrometry (GCMS/MS) or Liquid Chromatography-Mass Spectrometry (LCMS/MS) using multiple reaction monitoring (MRM). Although very useful for regulatory purposes, targeted chemical analysis can only provide data on the compounds (and specific metabolites) monitored. Ecotoxicology methods additionally ensure that any by-products produced or unknown estrogenic compounds present are also assessed via measurement of their biological activity. A number of in vitro bioassays including the Yeast Estrogen Screen (YES) are available to measure the estrogenic activity of wastewater samples. Chemical analysis in conjunction with in vivo and in vitro bioassays provides a useful toolbox for assessment of the efficacy and suitability of wastewater treatment processes with respect to estrogenic endocrine disrupting compounds. This paper utilizes a battery of chemical and ecotoxicology tests to assess conventional, advanced and emerging wastewater treatment processes in laboratory and field studies.

Endocrine Disrupting Compounds (EDC) pose a substantial risk to the aquatic environment. Municipal wastewater treatment plants are major contributors to the estrogenic potency of surface waters. The methodology provided in this paper allows for an assessment of the efficacy and suitability of wastewater treatment processes with respect to EDC removal.

Endocrine Disrupting Compounds pose a substantial risk to the aquatic environment. Ethinylestradiol (EE2) and estrone (E1) have recently been included in ...

Empirical, Metagenomic, and Computational Techniques Illuminate the Mechanisms by which Fungicides Compromise Bee Health

Growers often use fungicide sprays during bloom to protect crops against disease, which exposes bees to fungicide residues. Although considered &#34;bee-safe,&#34; there is mounting evidence that fungicide residues in pollen are associated with bee declines (for both honey and bumble bee species). While the mechanisms remain relatively unknown, researchers have speculated that bee-microbe symbioses are involved. Microbes play a pivotal role in the preservation and/or processing of pollen, which serves as nutrition for larval bees. By altering the microbial community, it is likely that fungicides disrupt these microbe-mediated services, and thereby compromise bee health. This manuscript describes the protocols used to investigate the indirect mechanism(s) by which fungicides may be causing colony decline. Cage experiments exposing bees to fungicide-treated flowers have already provided the first evidence that fungicides cause profound colony losses in a native bumble bee (Bombus impatiens). Using field-relevant doses of fungicides, a series of experiments have been developed to provide a finer description of microbial community dynamics of fungicide-exposed pollen. Shifts in the structural composition of fungal and bacterial assemblages within the pollen microbiome are investigated by next-generation sequencing and metagenomic analysis. Experiments developed herein have been designed to provide a mechanistic understanding of how fungicides affect the microbiome of pollen-provisions. Ultimately, these findings should shed light on the indirect pathway through which fungicides may be causing colony declines.

Microbial consortia within bumble bee hives enrich and preserve pollen for bee larvae. Using next generation sequencing, along with laboratory and field-based experiments, this manuscript describes protocols used to test the hypothesis that fungicide residues alter the pollen microbiome, and colony demographics, ultimately leading to colony loss.

Growers often use fungicide sprays during bloom to protect crops against disease, which exposes bees to fungicide residues. Although considered ...

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx

Nitrogen oxides (NOx = NO + NO2) are a family of atmospheric trace gases that have great impact on the environment. NOx concentrations directly influence the oxidizing capacity of the atmosphere through interactions with ozone and hydroxyl radicals. The main sink of NOx is the formation and deposition of nitric acid, a component of acid rain and a bioavailable nutrient. NOx is emitted from a mixture of natural and anthropogenic sources, which vary in space and time. The collocation of multiple sources and the short lifetime of NOx make it challenging to quantitatively constrain the influence of different emission sources and their impacts on the environment. Nitrogen isotopes of NOx have been suggested to vary amongst different sources, representing a potentially powerful tool to understand the sources and transport of NOx. However, previous methods of collecting atmospheric NOx integrate over long (week to month) time spans and are not validated for the efficient collection of NOx in relevant, diverse field conditions. We report on a new, highly efficient field-based system that collects atmospheric NOx for isotope analysis at a time resolution between 30 min and 2 hr. This method collects gaseous NOx in solution as nitrate with 100% efficiency under a variety of conditions. Protocols are presented for collecting air in urban settings under both stationary and mobile conditions. We detail the advantages and limitations of the method and demonstrate its application in the field. Data from several deployments are shown to 1) evaluate field-based collection efficiency by comparisons with in situ NOx concentration measurements, 2) test the stability of stored solutions before processing, 3) quantify in situ reproducibility in a variety of urban settings, and 4) demonstrate the range of N isotopes of NOx detected in ambient urban air and on heavily traveled roadways.

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx

Previous work suggests that the nitrogen isotopic composition of atmospheric nitrogen oxides might distinguish the influence of different sources in the environment. We report on an automated, mobile, field-based method for the high collection efficiency of atmospheric NOx for N isotopic analysis at an hourly time resolution.

Nitrogen oxides (NOx = NO + NO2) are a family of atmospheric trace gases that have great impact on the environment. NOx concentrations directly influence ...

The Calibration and Use of Capacitance Sensors to Monitor Stem Water Content in Trees

Water transport and storage through the soil-plant-atmosphere continuum is critical to the terrestrial water cycle, and has become a major research focus area. Biomass capacitance plays an integral role in the avoidance of hydraulic impairment to transpiration. However, high temporal resolution measurements of dynamic changes in the hydraulic capacitance of large trees are rare. Here, we present procedures for the calibration and use of capacitance sensors, typically used to monitor soil water content, to measure the volumetric water content in trees in the field. Frequency domain reflectometry-style observations are sensitive to the density of the media being studied. Therefore, it is necessary to perform species-specific calibrations to convert from the sensor-reported values of dielectric permittivity to volumetric water content. Calibration is performed on a harvested branch or stem cut into segments that are dried or re-hydrated to produce a full range of water contents used to generate a best-fit regression with sensor observations. Sensors are inserted into calibration segments or installed in trees after pre-drilling holes to a tolerance fit using a fabricated template to ensure proper drill alignment. Special care is taken to ensure that sensor tines make good contact with the surrounding media, while allowing them to be inserted without excessive force. Volumetric water content dynamics observed via the presented methodology align with sap flow measurements recorded using thermal dissipation techniques and environmental forcing data. Biomass water content data can be used to observe the onset of water stress, drought response and recovery, and has the potential to be applied to the calibration and evaluation of new plant-level hydrodynamics models, as well as to the partitioning of remotely sensed moisture products into above- and belowground components.

The hydraulic capacitance of biomass is a key component of the vegetation water budget, which serves as a buffer against short and long-term drought stresses. Here, we present a protocol for the calibration and use of soil moisture capacitance sensors to monitor water content in the stems of large trees.

Water transport and storage through the soil-plant-atmosphere continuum is critical to the terrestrial water cycle, and has become a major research focus ...

Stress Distribution During Cold Compression of Rocks and Mineral Aggregates Using Synchrotron-based X-Ray Diffraction

We report detailed procedures for performing compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus (D-DIA) coupled with synchrotron X-radiation. A cube-shaped sample assembly is prepared and compressed, at room temperature, by a set of four X-ray transparent sintered diamond anvils and two tungsten carbide anvils, in the lateral and the vertical planes, respectively. All six anvils are housed within a 250-ton hydraulic press and driven inward simultaneously by two wedged guide blocks. A horizontal energy dispersive X-ray beam is projected through and diffracted by the sample assembly. The beam is commonly in the mode of either white or monochromatic X-ray. In the case of white X-ray, the diffracted X-rays are detected by a solid-state detector array that collects the resulting energy dispersive diffraction pattern. In the case of monochromatic X-ray, the diffracted pattern is recorded using a two-dimensional (2-D) detector, such as an imaging plate or a charge-coupled device (CCD) detector. The 2-D diffraction patterns are analyzed to derive lattice spacings. The elastic strains of the sample are derived from the atomic lattice spacing within grains. The stress is then calculated using the predetermined elastic modulus and the elastic strain. Furthermore, the stress distribution in two-dimensions allow for understanding how stress is distributed in different orientations. In addition, a scintillator in the X-ray path yields a visible light image of the sample environment, which allows for the precise measurement of sample length changes during the experiment, yielding a direct measurement of volume strain on the sample. This type of experiment can quantify the stress distribution within geomaterials, which can ultimately shed light on the mechanism responsible for compaction. Such knowledge has the potential to significantly improve our understanding of key processes in rock mechanics, geotechnical engineering, mineral physics, and material science applications where compactive processes are important.

We report detailed procedures for compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus coupled with synchrotron X-radiation. Such experiments allow quantification of the stress distribution within samples, that ultimately sheds light on compaction processes in geomaterials.

We report detailed procedures for performing compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus (D-DIA) ...

Protocol for Producing Three-Dimensional Infrared Video of Freezing in Plants

Freezing in plants can be monitored using infrared (IR) thermography, because when water freezes, it gives off heat. However, problems with color contrast make 2-dimensions (2D) infrared images somewhat difficult to interpret. Viewing an IR image or the video of plants freezing in 3 dimensions (3D) would allow a more accurate identification of sites for ice nucleation as well as the progression of freezing. In this paper, we demonstrate a relatively simple means to produce a 3D infrared video of a strawberry plant freezing. Strawberry is an economically important crop that is subjected to unexpected spring freeze events in many areas of the world. An accurate understanding of the freezing in strawberry will provide both breeders and growers with more economical ways to prevent any damage to plants during freezing conditions.
The technique involves a positioning of two IR cameras at slightly different angles to film the strawberry freezing. The two video streams will be precisely synchronized using a screen capture software that records both cameras simultaneously. The recordings will then be imported into the imaging software and processed using an anaglyph technique. Using red-blue glasses, the 3D video will make it easier to determine the precise site of ice nucleation on leaf surfaces.

Here, we present a protocol to image a strawberry plant freezing in 3 dimensions. Two infrared cameras positioned at slightly different angles are used to produce a red-blue anaglyph video to observe the freezing of the plant in 3 dimensions.

Freezing in plants can be monitored using infrared (IR) thermography, because when water freezes, it gives off heat. However, problems with color contrast ...

Long-term Video Tracking of Cohoused Aquatic Animals: A Case Study of the Daily Locomotor Activity of the Norway Lobster (Nephrops norvegicus)

We present a protocol related to a video-tracking technique based on the background subtraction and image thresholding that makes it possible to individually track cohoused animals. We tested the tracking routine with four cohoused Norway lobsters (Nephrops norvegicus) under light-darkness conditions for 5 days. The lobsters had been individually tagged. The experimental setup and the tracking techniques used are entirely based on the open source software. The comparison of the tracking output with a manual detection indicates that the lobsters were correctly detected 69% of the times. Among the correctly detected lobsters, their individual tags were correctly identified 89.5% of the times. Considering the frame rate used in the protocol and the movement rate of lobsters, the performance of the video tracking has a good quality, and the representative results support the validity of the protocol in producing valuable data for research needs (individual space occupancy or locomotor activity patterns). The protocol presented here can be easily customized and is, hence, transferable to other species where the individual tracking of specimens in a group can be valuable for answering research questions.

Long-term Video Tracking of Cohoused Aquatic Animals: A Case Study of the Daily Locomotor Activity of the Norway Lobster Nephrops norvegicus

Here we present a protocol to individually track animals over a long period of time. It uses computer vision methods to identify a set of manually constructed tags by using a group of lobsters as case study, simultaneously providing information on how to house, manipulate, and mark the lobsters.

We present a protocol related to a video-tracking technique based on the background subtraction and image thresholding that makes it possible to ...

Single-throughput Complementary High-resolution Analytical Techniques for Characterizing Complex Natural Organic Matter Mixtures

Natural organic matter (NOM) is composed of a highly complex mixture of thousands of organic compounds which, historically, proved difficult to characterize. However, to understand the thermodynamic and kinetic controls on greenhouse gas (carbon dioxide [CO2] and methane [CH4]) production resulting from the decomposition of NOM, a molecular-level characterization coupled with microbial proteome analyses is necessary. Further, climate and environmental changes are expected to perturb natural ecosystems, potentially upsetting complex interactions that influence both the supply of organic matter substrates and the microorganisms performing the transformations. A detailed molecular characterization of the organic matter, microbial proteomics, and the pathways and transformations by which organic matter is decomposed will be necessary to predict the direction and magnitude of the effects of environmental changes. This article describes a methodological throughput for comprehensive metabolite characterization in a single sample by direct injection Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), gas chromatography mass spectrometry (GC-MS), nuclear magnetic resonance (NMR) spectroscopy, liquid chromatography mass spectrometry (LC-MS), and proteomics analysis. This approach results in a fully-paired dataset which improves statistical confidence for inferring pathways of organic matter decomposition, the resulting CO2 and CH4 production rates, and their responses to environmental perturbation. Herein we present results of applying this method to NOM samples collected from peatlands; however, the protocol is applicable to any NOM sample (e.g., peat, forested soils, marine sediments, etc.).

This protocol describes a single throughput for complementary analytical and omics techniques culminating in a fully-paired characterization of natural organic matter and microbial proteomics in different ecosystems. This approach permits robust comparisons for identifying metabolic pathways and transformations important for describing greenhouse gas production and predicting responses to environmental change.