Authors gracefully thank Marc Steen and Natalia Lebedeva for the excellent support reviewing and discussing this manuscript.

The authors have nothing to disclose.

The need of decarbonizing the economy combined with increasing energy demands&#160;&#9472;&#160;resulting from socio-economic developments and from climate change &#9472;&#160;requires a major shift in the energy system to address challenges posed by global warming and fuel shortage1,2. Clean energy technologies such as wind energy and solar energy are regarded as best alternatives to a fossil-fuel dominated energy system3; however, they are intermittent and the storage of energy will help to ensure continuity of energy supply. Properties such as high specific energy density, stable cycling performance and efficiency make lithium-ion batteries (LIBs) promising candidates as electrochemical energy storage system. The cost and the lack of reliable operation of LIBs may hamper a wider application in the power grid, in the form of large stationary battery system4,5. An additional aspect to consider is that the combination of high energetic materials with flammable organic solvent-based electrolytes can lead to hazardous conditions such as fire, release of toxic gases and explosion6,7. Therefore, one must address safety issues in LIBs.
Since early commercialization, a number of accidents in current applications (portable electronic devices, electric cars, and auxiliary power unit in aircraft) were reported in the news8,9. For instance, despite high quality production, the Sony laptop batteries incident10, the two Boeing 787 incidents11,12, Samsung Galaxy Notes 7 incidents13 are assumed to happen by internal short circuits in a cell. Tests have been developed to assess safety hazards14,15,16,17. Overcharge, over-discharge, external heating, mechanical abuse and internal/external short-circuit are failure mechanisms that are known to trigger thermal runaway (TR)18 and have been included in some standards and regulations. During this process, a series of exothermic reactions occur causing a drastic and rapid increase in temperature. When the heat generated cannot be dissipated fast enough, this condition develops into a TR19,20. Additionally, a single cell can then generate sufficient heat to trigger the neighboring cells, within a module or within a pack assembly, into TR; creating a thermal propagation (TP) event. Mitigation strategies such as increasing cell spacing in a module, the use of insulation materials and a specific style of cell interconnecting tab have all proven to curb the propagation phenomenon21. Also, the electrolyte stability and the structure stability of various cathode materials in the presence of electrolyte, at elevated temperature, have been investigated in order to reduce the likelihood of TR22.
Juarez-Robles et al. showed the combined effects of the degradation mechanisms from long-term cycling and over-discharge on LIB cells23. Depending on the severity of the discharge, phenomena like Li plating, cathode particle cracking, dissolution of Cu current collector, cathode particle disintegration, formation of Cu and Li bridges were reported as the main degradation mechanisms observed in these tests. Furthermore, they studied the combined effect resulting from aging and overcharge on a LIB cell to shed light on the degradation mechanisms24. Due to the extent of the overcharge regime, degradation behaviors observed for the cell were capacity fade, electrolyte decomposition, Li plating, delamination of active material, particle cracking and production of gases. These combined abuse conditions may cause the active materials to undergo exothermic reactions that can generate sufficient heat to initiate thermal runaway.
To avoid safety-related problems, lithium-ion batteries have to pass several tests defined in various standards and regulations14. However, variety in cell designs (pouch, prismatic, cylindrical), applicability of tests limited to a certain level (cell, module, pack), different evaluation and acceptance criteria defined, highlight the need to unify guidelines and safety requirements in standards and regulations25,26,27. A reliable, reproducible and controllable methodology, with uniform test conditions to trigger an internal short circuit (ISC) with subsequent TR, along with uniform evaluation criteria, is still under development28. Furthermore, there is not a single agreed protocol to assess the risks associated with the occurrence of TP in a battery during normal operation20,25.
In order to establish a testing protocol that simulates a realistic field failure scenario, a massive number of input parameter combinations (e.g., design parameters of the cell such as capacity, surface to volume ratio, thickness of the electrodes, ISC triggering method, location, etc.) need to be investigated experimentally to determine the best way to trigger TR induced by internal short circuit. This requires prohibitive lab efforts and costs. An alternative approach consists of the use of modeling and simulation to design a suitable triggering method. Nonetheless, 3D-thermal modeling of batteries can be prohibitively computationally expensive, considering the number of assessments needed to cover the effect of all possible combinations of parameters potentially governing TR induced by an internal short circuit.
In the literature, thermal decomposition models have been developed to simulate electrochemical reactions and thermal response of different types of lithium-ion batteries under various abuse conditions, such as nail penetration29, overcharge30, or conventional oven test31. In an effort to understand the cathode material stability, Parmananda et al. compiled experimental data of accelerating rate calorimeter (ARC) from the literature32. They have extracted kinetic parameters from these data, developed a model to simulate the calorimetric experiment and use these kinetic parameters for thermal stability&#160;prediction of a range of cathode materials32.
In references29,30,31 and numerous other studies, a combination of the same models33,34,35,36&#160;&#9472;&#160;describing&#160;respectively; heat release from decomposition of anode and solid electrolyte interface (SEI) layer; decomposition of cathode and decomposition of electrolyte&#160;&#9472;&#160;has been used repeatedly during several years as the basis for modeling thermal runaway. The latter has also been improved over time, for instance, by adding venting conditions37. However, this series of model was initially developed to capture the onset temperature of a TR and not for modeling thermal runaway severity.
Since thermal runaway is an uncontrolled thermal decomposition of battery components, it is of utmost importance to identify the decomposition reactions in anode and cathode to be able to design safer Li-ion batteries cells and more accurate testing methodologies. To this purpose, the goal of this study is the investigation of thermal decomposition mechanisms in NMC (111) cathode and graphite anode for the development of a simplified yet sufficiently accurate reaction kinetic model, which can be used in simulation of TR.
Here, we propose the use of coupled analytical equipment: Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA) in a single simultaneous thermal analysis (STA) instrument. This equipment is coupled to the gas analysis system, which consists of Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS). The hyphenated STA/FTIR/GC-MS techniques will allow us to acquire a better understanding of the causes and processes of thermal runaway in a single cell. Moreover, this will help to identify thermal decomposition processes. Hyphenation refers to the online combination of different analytical techniques.
The set-up of this custom-made integrated system is shown in Figure 1. The STA equipment, used in the present study, is located inside a glovebox, which guarantees the handling of components in a protective atmosphere. The latter is coupled with the FTIR and GC-MS via heated transfer lines (150 &#176;C) to avoid the condensation of evaporated materials along the lines. The hyphenation of these analytical techniques allows simultaneous study of thermal properties and identification of released gases, providing information of the mechanisms of the thermally induced decomposition reactions. In order to further reduce the impact of unwanted chemical reactions in the electrodes during sample preparation, sample handling and sample loading are performed inside an argon-filled glove box. The disassembled electrodes are not rinsed nor any additional electrolytes are added to the crucible.
STA allows for the identification of phase transitions during the heating process, along with accurate determination of temperatures and enthalpies associated with these phase transitions, including those without mass change. The combination of on-line FTIR and GC-MS methods with the STA provides a qualitative assessment of gases evolved from the sample during its thermal decomposition. This is the key in identifying thermally induced reaction mechanisms. Indeed, STA/FTIR/GC-MS coupled system allows correlating the mass changes, heat flow, and detected gases.
FTIR and GC-MS each have their advantages and limitations. The high sensitivity of GC-MS allows rapid and easy detection of molecules from peaks of low intensity. Furthermore, FTIR data well complement the information provided by MS spectrum patterns to achieve the structural identification of organic volatile species. However, FTIR is less sensitive. In addition, diatomic molecules, such as H2, N2, O2, do not possess a permanent dipole moment and are not infrared active. Therefore, they cannot be detected using infrared absorption. On the contrary, small molecules such as CO2, CO, NH3, and H2O can be identified to a high degree of certainty38. Altogether, the information provided by these complementary methods makes it possible to gain insight of the gases emitted during thermal characterization.
In order to check the state of the art in terms of thermal decomposition reactions identified for Lithium Nickel Manganese Cobalt oxide (NMC (111)) cathode, graphite (Gr) anode and 1M LiPF6 in ethylene carbonate (EC)/dimethyl carbonate (DMC) = 50/50 (v/v) electrolyte, a literature review was performed. Table 1, Table 2, and Table 3 summarize the main findings.
In the field of thermal characterization of battery components, the sample preparation method has a significant effect on DSC experimental results since this has an influence on the DSC signal. Many studies have reported different approaches in terms of electrode handling. Some variations include 1) scratching active material from electrode without prior rinsing nor adding extra amount of electrolyte, e.g.,54,55; 2) rinsing/drying/scratching active material and adding a given amount of electrolyte with it in the crucible e.g.,55,56; 3) rinsing/drying/scratching active material without adding electrolyte at a later stage (e.g., see reference57). However, in the literature, there is no general agreement on the sample preparation techniques. Washing the electrode affects the integrity and the reactants in the SEI58, which in turn, modify the amount of heat generated from its decomposition34,59. On the other hand, there is no clear indication or sufficient details on the amount of added electrolyte to the harvested materials prior to thermal analysis.
In this work, the SEI modification is minimized by not washing the electrode and excluding electrolyte addition, in an attempt to characterize the electrode material in its original state, while keeping its residual electrolyte content. Realizing that SEI thermal decomposition is a potential trigger to thermal runaway, this preparation method is expected to allow for a better understanding of the thermal properties of the electrode, under test conditions, without the dissolution of some SEI products. Indeed, the breakdown of SEI layer on the anode is generally the first stage of battery failure that initiates a self-heating process39,41,60.
Another important issue in thermal analysis is the measurement conditions (type of crucible, open/closed crucible, atmosphere) that are affecting the DSC signal to be measured. In this case, the use of a hermetically closed crucible is clearly not suitable for the hyphenated STA/GC-MS/FTIR techniques, which implies the identification of evolved gases. In a semi-closed system, the size of the opening in the perforated crucible lid can have a strong influence on the measurement results. If the size is small, the thermal data is comparable to a sealed crucible61. On the contrary, a large hole in the lid is expected to decrease the measured thermal signal because of the early release of low temperature decomposition products. As a result, these species would not be involved in higher temperature processes61. Indeed, a closed or semi-closed system allows longer residence time of the species, transformed from condensed to vapor phase inside the crucible. A laser-cut vent hole of 5 &#181;m in the crucible lid has been selected for the investigation of thermal behavior and evolved gases of graphite anode and NMC (111) cathode. Considering the size of the laser-cut hole, we assume the system inside the crucible may most probably depict, a simple but reasonable approximation of the dynamic inside both, a closed battery cell and a battery cell venting.
This present work is built upon an earlier publication by the same authors48. However, this paper focuses in more detail on the experimental part, highlighting the benefits of the used techniques and testing conditions to reach the goal of this work.
To the best of the authors&#39; knowledge, there is limited research published on the thermal behavior of electrode material, using of the exact combination of these analytical instruments STA/FTIR/GC-MS, analytical parameters and sample preparation/ handling to elucidate chemical reaction mechanisms at material level during thermal decomposition. At the cell level, Fernandes et al. investigated the evolved gases in a continuous way, using FTIR and GC-MS, in a battery cylindrical cell undergoing an overcharged abuse test, in a closed chamber62. They have identified and quantified the gases during this test, but the understanding of reaction mechanisms still remains unclear. Furthermore, to develop a TR runaway model, Ren et al. have also conducted DSC experiments at material level to calculate kinetic triplet parameters of exothermic reactions55. They have identified six exothermic processes, but the reaction mechanisms were not determined, and they did not use coupled gas analysis techniques.
On the other hand, Feng et al. have proposed a three-stage TR mechanism in LIB cell with three characteristic temperatures that can be used as indexes to assess thermal safety of battery63. For this purpose, they have used a thermal database with data from ARC. Nevertheless, details of the chemical reactions underlying these three mechanisms are not provided.
In this study, the data obtained through these thermal analysis methods are essential for the development of the kinetic model where the main thermal decomposition processes should be determined and properly described. The kinetic thermal triplet, namely the activation energy, frequency factor, and heat of reaction, are calculated for the different sub-processes taking place in both electrodes during thermally induced decomposition, using three different heating rates: 5, 10 and 15 &#176;C /min. When applicable, the Kissinger method64,65 was used for the determination of activation energy and frequency factor, following the Arrhenius equation. The Kissinger method is applicable when DSC peak shifts to higher temperature with increasing heating rate. The reaction enthalpy is obtained by integrating the area of the reaction peak, as measured by DSC. From these thermal data and the measurement uncertainties, a reaction kinetic model is proposed to simulate the dynamics of a thermal runaway. In the second part of this work66, this newly developed model will be used to determine the probability of a TR event as a function of the parameters of an ISC triggering method.
The scheme depicted in Figure 2 summarizes the sequence of steps needed to undertake the protocol. The first step consists of assembling the electrochemical cell with the battery materials under investigation, namely, NMC (111)/Gr.
In order to be able to harvest the battery materials after electrochemical cycling and state of charge (SOC) adjustment to 100%, a re-sealable electrochemical cell supplied by EL-CELL (ECC-PAT-Core) was used. This allowed a smooth cell opening process without damage to the electrodes. Once the battery materials are harvested, thermal characterization is carried out.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Glove box MB 200B</td>
			<td>MBraun</td>
			<td></td>
			<td>Glove box filled with argon to ensure inert atmosphere.&#160; H2O &#60; 0.1 ppm; O2 &#60; 0.1 ppm</td>
		</tr>
		<tr>
			<td>&#160;STA 449 F3 Jupiter&#174;</td>
			<td>Netzsch</td>
			<td></td>
			<td>Simultaneous Thermal Analysis for thermal characterization. The STA equipment is located inside the glove box. Type of furnace used: silver</td>
		</tr>
		<tr>
			<td>Agilent 7820A GC- Agilent 5977E MS</td>
			<td>Agilent</td>
			<td></td>
			<td>Gas Chromatograph equipped with an quadrupole Mass Spectrometer. GC-MS is coupled to STA via heated lines in order to identify the released gases during thermal characterization</td>
		</tr>
		<tr>
			<td>Bruker Vertex 70 V FTIR</td>
			<td>Bruker</td>
			<td></td>
			<td>&#160;Fourier Transform Infrared spectrometer equipped with a TG-IR box. FTIR is coupled to STA via heated lines in order to identify the released gases during thermal characterization</td>
		</tr>
		<tr>
			<td>18mm graphite electrode disc</td>
			<td>Customcell</td>
			<td>363586011</td>
			<td>graphite electrode disc with an area capacity of 2.24 mAh.cm-2</td>
		</tr>
		<tr>
			<td>18mm NMC (111) electrode disc</td>
			<td>Customcell</td>
			<td>363662011</td>
			<td>LiNiMnCoO2 electrode disc with stochiometry ratio 111 and an area capacity of 2.0 mAh.cm-2</td>
		</tr>
		<tr>
			<td>1.0 M LiPF6 in EC/DMC=50/50 (v/v)</td>
			<td>Sigma-Aldrich</td>
			<td>746711-100ML</td>
			<td>Electrolyte</td>
		</tr>
		<tr>
			<td>&#160;2325 trilayer film separator</td>
			<td>Celgard&#174;</td>
			<td></td>
			<td>Film separator. 22 mm diameter discs should be cut from the film</td>
		</tr>
		<tr>
			<td>High precision cutting pliers</td>
			<td>EL Cell</td>
			<td></td>
			<td>1) Used in paragraph 2 for cutting with a fixed 18 mm diameter the bare copper and aluminum foils (non-coated). These current collectors were bought from the same supplier as for the elecrode discs 2) Used for cutting 22 mm diameter Cegard separator discs</td>
		</tr>
		<tr>
			<td>ECC-PAT-Core (2014 version) kit using: a) reusable stainless steel (SS) upper plunger, b) reusable SS lower plunger of type 50 (size in &#181;m), c) single-use PP insulation sleeves</td>
			<td>&#160;EL Cell</td>
			<td></td>
			<td>Electrochemical cell assembly</td>
		</tr>
		<tr>
			<td>&#160;Maccor Series 4000</td>
			<td>Maccor</td>
			<td></td>
			<td>Battery cycler. It was used to cycle 2 times the electrochemical cell and to adjust afterwards the SOC to 100%</td>
		</tr>
		<tr>
			<td>aluminum crucibles with 5 &#181;m laser-pierced lid</td>
			<td>Netzsch</td>
			<td>6.239.2-64.81.00</td>
			<td>Crucible used for the thermal analysis and identification of released gases from cycled electrode material (graphite anode or NMC (111) cathode)</td>
		</tr>
		<tr>
			<td>Precision balance AE240&#160; type AE240-S inside Glove box</td>
			<td>Mettler Toledo</td>
			<td></td>
			<td>Battery materials are measured at &#181;g precision</td>
		</tr>
		<tr>
			<td>Analogue digital multimeter ABB model MetraWatt M2005</td>
			<td>Gossen MetraWatt</td>
			<td></td>
			<td>Used to measure of the freshly assembled electrochemical cell in paragraph 1.2.6</td>
		</tr>
	</tbody>
</table>

identification and quantification of decomposition mechanisms in lithium-ion batteries; input to heat flow simulation for modeling thermal runaway

The risks and possible accidents related to the normal use of lithium-ion batteries remain a serious concern. In order to get a better understanding of thermal runaway (TR), the exothermic decomposition reactions in anode and cathode were studied, using a Simultaneous Thermal Analysis (STA)/Gas Chromatography-Mass Spectrometry (GC-MS)/Fourier Transform Infrared (FTIR) spectrometer system. These techniques allowed the identification of the reaction mechanisms in each electrode, owing to the analysis of evolved gaseous species, the amount of heat released and mass loss. These results provided insight into the thermal events happening within a broader temperature range than covered in previously published models. This allowed the formulation of an improved thermal model to depict TR. The heat of reaction, activation energy, and frequency factor (thermal triplets) for each major exothermic process at material level were investigated in a Lithium Nickel-Manganese-Cobalt-Oxide (NMC (111))-Graphite battery cell. The results were analyzed, and their kinetics were derived. These data can be used to successfully simulate the experimental heat flow.

Watch this Scientific Journal Video about Identification and Quantification of Decomposition Mechanisms in Lithium-Ion Batteries; Input to Heat Flow Simulation for Modeling Thermal Runaway at JoVE.com

Identification and Quantification of Decomposition Mechanisms in Lithium-Ion Batteries; Input to Heat Flow Simulation for Modeling Thermal Runaway

This work aims at determining the reaction kinetics of Li-ion battery cathode and anode materials undergoing thermal runaway (TR). Simultaneous Thermal Analysis (STA)/Fourier Transform Infrared (FTIR) spectrometer/Gas Chromatography Mass Spectrometry (GC-MS) were used to reveal thermal events and to detect evolved gases.

The risks and possible accidents related to the normal use of lithium-ion batteries remain a serious concern. In order to get a better understanding of ...

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4.3K Views.  European Commission, Joint Research Centre (JRC), The Netherlands. This work aims at determining the reaction kinetics of Li-ion battery cathode and anode materials undergoing thermal runaway (TR). Simultaneous Thermal Analysis (STA)/Fourier Transform Infrared (FTIR) spectrometer/Gas Chromatography Mass Spectrometry (GC-MS) were used to reveal thermal events and to detect evolved gases.

Video: Identification and Quantification of Decomposition Mechanisms in Lithium-Ion Batteries; Input to Heat Flow Simulation for Modeling Thermal Runaway

Diffuse Reflectance Infrared Spectroscopic Identification of Dispersant/Particle Bonding Mechanisms in Functional Inks

In additive manufacturing, or 3D printing, material is deposited drop by drop, to create micron to macroscale layers. A typical inkjet ink is a colloidal dispersion containing approximately ten components including solvent, the nano to micron scale particles which will comprise the printed layer, polymeric dispersants to stabilize the particles, and polymers to tune layer strength, surface tension and viscosity. To rationally and efficiently formulate such an ink, it is crucial to know how the components interact. Specifically, which polymers bond to the particle surfaces and how are they attached? Answering this question requires an experimental procedure that discriminates between polymer adsorbed on the particles and free polymer. Further, the method must provide details about how the functional groups of the polymer interact with the particle. In this protocol, we show how to employ centrifugation to separate particles with adsorbed polymer from the rest of the ink, prepare the separated samples for spectroscopic measurement, and use Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS) for accurate determination of dispersant/particle bonding mechanisms. A significant advantage of this methodology is that it provides high level mechanistic detail using only simple, commonly available laboratory equipment. This makes crucial data available to almost any formulation laboratory. The method is most useful for inks composed of metal, ceramic, and metal oxide particles in the range of 100 nm or greater. Because of the density and particle size of these inks, they are readily separable with centrifugation. Further, the spectroscopic signatures of such particles are easy to distinguish from absorbed polymer. The primary limitation of this technique is that the spectroscopy is performed ex-situ on the separated and dried particles as opposed to the particles in dispersion. However, results from attenuated total reflectance spectra of the wet separated particles provide evidence for the validity of the DRIFTS measurement.

Formulation of stable, functional inks is critical to expanding the applications of additive manufacturing. In turn, knowledge of the mechanisms of dispersant/particle bonding is required for effective ink formulation. Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS) is presented as a simple, inexpensive way to gain insight into these mechanisms.

In additive manufacturing, or 3D printing, material is deposited drop by drop, to create micron to macroscale layers.  A typical inkjet ink is a colloidal ...

Optimization of Synthetic Proteins: Identification of Interpositional Dependencies Indicating Structurally and/or Functionally Linked Residues

Protein alignments are commonly used to evaluate the similarity of protein residues, and the derived consensus sequence used for identifying functional units (e.g., domains). Traditional consensus-building models fail to account for interpositional dependencies &#8211; functionally required covariation of residues that tend to appear simultaneously throughout evolution and across the phylogentic tree. These relationships can reveal important clues about the processes of protein folding, thermostability, and the formation of functional sites, which in turn can be used to inform the engineering of synthetic proteins. Unfortunately, these relationships essentially form sub-motifs which cannot be predicted by simple &#8220;majority rule&#8221; or even HMM-based consensus models, and the result can be a biologically invalid &#8220;consensus&#8221; which is not only never seen in nature but is less viable than any extant protein. We have developed a visual analytics tool, StickWRLD, which creates an interactive 3D representation of a protein alignment and clearly displays covarying residues. The user has the ability to pan and zoom, as well as dynamically change the statistical threshold underlying the identification of covariants. StickWRLD has previously been successfully used to identify functionally-required covarying residues in proteins such as Adenylate Kinase and in DNA sequences such as endonuclease target sites.

Synthetic protein sequences based on consensus motifs typically ignore co-evolving residues, that imply interpositional dependencies (IPDs). IPDs can be essential to activity, and designs that disregard them may result in suboptimal results. This protocol uses StickWRLD to identify IPDs and help inform rational protein design, resulting in more efficient results.

Protein alignments are commonly used to evaluate the similarity of protein residues, and the derived consensus sequence used for identifying functional ...

Radiolabeling and Quantification of Cellular Levels of Phosphoinositides by High Performance Liquid Chromatography-coupled Flow Scintillation

Phosphoinositides (PtdInsPs) are essential signaling lipids responsible for recruiting specific effectors and conferring organelles with molecular identity and function. Each of the seven PtdInsPs varies in their distribution and abundance, which are tightly regulated by specific kinases and phosphatases. The abundance of PtdInsPs can change abruptly in response to various signaling events or disturbance of the regulatory machinery. To understand how these events lead to changes in the amount of PtdInsPs and their resulting impact, it is important to quantify PtdInsP levels before and after a signaling event or between control and abnormal conditions. However, due to their low abundance and similarity, quantifying the relative amounts of each PtdInsP can be challenging. This article describes a method for quantifying PtdInsP levels by metabolically labeling cells with 3H-myo-inositol, which is incorporated into PtdInsPs. Phospholipids are then precipitated and deacylated. The resulting soluble 3H-glycero-inositides are further extracted, separated by high-performance liquid chromatography (HPLC), and detected by flow scintillation. The labeling and processing of yeast samples is described in detail, as well as the instrumental setup for the HPLC and flow scintillator. Despite losing structural information regarding acyl chain content, this method is sensitive and can be optimized to concurrently quantify all seven PtdInsPs in cells.

Phosphoinositides are signaling lipids whose relative abundance rapidly changes in response to various stimuli. This article describes a method to measure the abundance of phosphoinositides by metabolically labeling cells with 3H-myo-inositol, followed by extraction and deacylation. Extracted glycero-inositides are then separated by high-performance liquid chromatography and quantified by flow scintillation.

Phosphoinositides (PtdInsPs) are essential signaling lipids responsible for recruiting specific effectors and conferring organelles with molecular ...

Immunostaining Phospho-epitopes in Ciliated Organs of Whole Mount Zebrafish Embryos

The rapid proliferation of cells, the tissue-specific expression of genes and the emergence of signaling networks characterize early embryonic development of all vertebrates. The kinetics and location of signals - even within single cells - in the developing embryo complements the identification of important developmental genes. Immunostaining techniques are described that have been shown to define the kinetics of intracellular and whole animal signals in structures as small as primary cilia. The techniques for fixing, imaging and processing images using a laser-scanning confocal compound microscope can be completed in as few as 36 hr.
Zebrafish (Danio rerio) is a desirable organism for investigators who seek to conduct studies in a vertebrate species that is affordable and relevant to human disease. Genetic knockouts or knockdowns must be confirmed by the loss of the actual protein product. Such confirmation of protein loss can be achieved using the techniques described here. Clues into signaling pathways can also be deciphered by using antibodies that are reactive with proteins that have been post-translationally modified by phosphorylation. Preserving and optimizing the phosphorylated state of an epitope is therefore critical to this determination and is accomplished by this protocol.
This study describes techniques to fix embryos during the first 72 hr of development and co-localize a variety of relevant epitopes with cilia in the Kupffer&#39;s Vesicle (KV), the kidney and the inner ear. These techniques are straightforward, do not require dissection and can be completed in a relatively short period of time. Projecting confocal image stacks into a single image is a useful means of presenting these data.

Techniques are described to immunostain phospho-epitopes in whole zebrafish embryos and then conduct two-color fluorescent confocal localization in cellular structures as small as primary cilia. The techniques for fixing and imaging can define the location and kinetics of the appearance or activation of specific proteins.

The rapid proliferation of cells, the tissue-specific expression of genes and the emergence of signaling networks characterize early embryonic development ...

Preparation of Biopolymer Aerogels Using Green Solvents

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers (gelatin, agar, cellulose), only recently have biomasses been recognized as an abundant source of chemically diverse macromolecules for functional aerogel materials. Biopolymer aerogels (pectin, alginate, chitosan, cellulose, etc.) exhibit both specific inheritable functions of starting biopolymers and distinctive features of aerogels (80-99% porosity and specific surface up to 800 m2/g). This synergy of properties makes biopolymer aerogels promising candidates for a wide gamut of applications such as thermal insulation, tissue engineering and regenerative medicine, drug delivery systems, functional foods, catalysts, adsorbents and sensors. This work demonstrates the use of pressurized carbon dioxide (5 MPa) for the ionic cross linking of amidated pectin into hydrogels. Initially a biopolymer/salt dispersion is prepared in water. Under pressurized CO2 conditions, the pH of the biopolymer solution is lowered to 3 which releases the crosslinking cations from the salt to bind with the biopolymer yielding hydrogels. Solvent exchange to ethanol and further supercritical CO2 drying (10 - 12 MPa) yield aerogels. Obtained aerogels are ultra-porous with low density (as low as 0.02 g/cm3), high specific surface area (350 - 500 m2/g) and pore volume (3 - 7 cm3/g for pore sizes less than 150 nm).

A new way for the production of biopolymer-based aerogels by carbon dioxide (CO2) induced gelation is shown. The technique utilizes pressurized carbon dioxide (5 MPa) for the production of biopolymer hydrogels and supercritical CO2 (12 MPa) to convert gels into aerogels. The only solvents needed besides CO2 are water and ethanol.

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers ...

Detection and Quantification of Plasmodium falciparum in Aqueous Red Blood Cells by Attenuated Total Reflection Infrared Spectroscopy and Multivariate Data Analysis

We demonstrate a method of quantification and detection of parasites in aqueous red blood cells (RBCs) by using a simple benchtop Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectrometer in conjunction with Multivariate Data Analysis (MVDA). 3D7 P. falciparum were cultured to 10% parasitemia ring stage parasites and used to spike fresh donor isolated RBCs to create a dilution series between 0&#8211;1%. 10 &#181;L of each sample were placed onto the center of the ATR diamond window to acquire the spectrum. The sample data was treated to improve the signal to noise ratio and to remove the contribution of water, and then the second derivative was applied to resolve spectral features. The data were then analyzed using two types of MVDA: first Principal Component Analysis (PCA) to determine any outliers and then Partial Least Squares Regression (PLS-R) to build the quantification model.

Detection and Quantification of Plasmodium falciparum in Aqueous Red Blood Cells by Attenuated Total Reflection Infrared Spectroscopy and Multivariate Data Analysis

Here, we present a protocol for the detection and quantification of Plasmodium falciparum in infected aqueous red blood cells using an attenuated total reflection infrared spectrometer and multivariate data analysis.

We demonstrate a method of quantification and detection of parasites in aqueous red blood cells (RBCs) by using a simple benchtop Attenuated Total ...

Elemental-sensitive Detection of the Chemistry in Batteries through Soft X-ray Absorption Spectroscopy and Resonant Inelastic X-ray Scattering

Energy storage has become more and more a limiting factor of today's sustainable energy applications, including electric vehicles and green electric grid based on volatile solar and wind sources. The pressing demand of developing high-performance electrochemical energy storage solutions, i.e., batteries, relies on both fundamental understanding and practical developments from both the academy and industry. The formidable challenge of developing successful battery technology stems from the different requirements for different energy-storage applications. Energy density, power, stability, safety, and cost parameters all have to be balanced in batteries to meet the requirements of different applications. Therefore, multiple battery technologies based on different materials and mechanisms need to be developed and optimized. Incisive tools that could directly probe the chemical reactions in various battery materials are becoming critical to advance the field beyond its conventional trial-and-error approach. Here, we present detailed protocols for soft X-ray absorption spectroscopy (sXAS), soft X-ray emission spectroscopy (sXES), and resonant inelastic X-ray scattering (RIXS) experiments, which are inherently elemental-sensitive probes of the transition-metal 3d and anion 2p states in battery compounds. We provide the details on the experimental techniques and demonstrations revealing the key chemical states in battery materials through these soft X-ray spectroscopy techniques.

Here, we present a protocol for typical experiments of soft X-ray absorption spectroscopy (sXAS) and resonant inelastic X-ray scattering (RIXS) with applications in battery material studies.

Energy storage has become more and more a limiting factor of today's sustainable energy applications, including electric vehicles and green electric grid ...

Chemical Synthesis of Porous Barium Titanate Thin Film and Thermal Stabilization of Ferroelectric Phase by Porosity-Induced Strain

Barium titanate (BaTiO3, hereafter BT) is an established ferroelectric material first discovered in the 1940s and still widely used because of its well-balanced ferroelectricity, piezoelectricity, and dielectric constant. In addition, BT does not contain any toxic elements. Therefore, it is considered to be an eco-friendly material, which has attracted considerable interest as a replacement for lead zirconate titanate (PZT). However, bulk BT loses its ferroelectricity at approximately 130 &#176;C, thus, it cannot be used at high temperatures. Because of the growing demand for high-temperature ferroelectric materials, it is important to enhance the thermal stability of ferroelectricity in BT. In previous studies, strain originating from the lattice mismatch at hetero-interfaces has been used. However, the sample preparation in this approach requires complicated and expensive physical processes, which are undesirable for practical applications.
In this study, we propose a chemical synthesis of a porous material as an alternative means of introducing strain. We synthesized a porous BT thin film using a surfactant-assisted sol-gel method, in which self-assembled amphipathic surfactant micelles were used as an organic template. Through a series of studies, we clarified that the introduction of pores had a similar effect on distorting the BT crystal lattice, to that of a hetero-interface, leading to the enhancement and stabilization of ferroelectricity. Owing to its simplicity and cost effectiveness, this fabrication process has considerable advantages over conventional methods.

Here, we present a protocol for the synthesis of porous barium titanate (BaTiO3) thin film by a surfactant-assisted sol-gel method, in which self-assembled amphipathic surfactant micelles are used as an organic template.

Barium titanate (BaTiO3, hereafter BT) is an established ferroelectric material first discovered in the 1940s and still widely used because of its ...

Extending the Lifespan of Soluble Lead Flow Batteries with a Sodium Acetate Additive

In this report, we present a method for the construction of a soluble lead flow battery (SLFB) with an extended cycle life. By supplying an adequate amount of sodium acetate (NaOAc) to the electrolyte, a cycle life extension of over 50% is demonstrated for SLFBs via long-term galvanostatic charge/discharge experiments. A higher quality of the PbO2 electrodeposit at the positive electrode is quantitatively validated for NaOAc-added electrolyte by throwing index (TI) measurements. Images acquired by scanning electron microscopy (SEM) also exhibit more integrated PbO2 surface morphology when the SLFB is operated with the NaOAc-added electrolyte. This work indicates that electrolyte modification can be a plausible route to economically enable SLFBs for large-scale energy storage.

A protocol for the construction of a soluble lead flow battery with an extended lifespan, in which sodium acetate is supplied in the methanesulfonic electrolyte as an additive, is presented.

In this report, we present a method for the construction of a soluble lead flow battery (SLFB) with an extended cycle life. By supplying an adequate ...

Quantification of Metal Leaching in Immobilized Metal Affinity Chromatography

Contamination of enzymes with metals leached from immobilized metal affinity chromatography (IMAC) columns poses a major concern for enzymologists, as many of the common di-and trivalent cations used in IMAC resins have an inhibitory effect on enzymes. However, the extent of metal leaching and the impact of various eluting and reducing reagents are poorly understood in large part due to the absence of simple and practical transition metal quantification protocols that use equipment typically available in biochemistry labs. To address this problem, we have developed a protocol to quickly quantify the amount of metal contamination in samples prepared using IMAC as a purification step. The method uses hydroxynaphthol blue (HNB) as a colorimetric indicator for metal cation content in a sample solution and UV-Vis spectroscopy as a means to quantify the amount of metal present, into the nanomolar range, based on the change in the HNB spectrum at 647 nm. While metal content in a solution has historically been determined using atomic absorption spectroscopy or inductively coupled plasma techniques, these methods require specialized equipment and training outside the scope of a typical biochemistry laboratory. The method proposed here provides a simple and fast way for biochemists to determine the metal content of samples using existing equipment and knowledge without sacrificing accuracy.

We present an assay for easy quantification of metals introduced to samples prepared using immobilized metal affinity chromatography. The method uses hydroxynaphthol blue as the colorimetric metal indicator and a UV-Vis spectrophotometer as the detector.

Contamination of enzymes with metals leached from immobilized metal affinity chromatography (IMAC) columns poses a major concern for enzymologists, as ...