This work was supported by the BOF grant for SG from Ghent University. AL is supported by the Rutgers University NSF Fuels-IGERT. SA is supported by the European Union Framework Programme 7 project &#8220;ProEthanol 2G.&#8221; SA and KR are supported by Ghent University Multidisciplinary Research Partnership (MRP)&#8212;Biotechnology for a sustainable economy (01 MRA 510W). JD is supported by an IOF Advanced grant (F2012/IOF-Advanced/094). KR is supported by by the ERC Starter Grant &#8220;Electrotalk&#8221;. The authors thank Tim Lacoere for designing the TOC art figure, Robin Declerck for building the strip and absorption columns and Kun Guo for providing the inoculum source.

<ol>
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The authors have nothing to disclose.

Diese Handschrift stellt die notwendigen Werkzeuge zur Einrichtung einer bioelektrochemische und eine elektrochemische Zelle für Ammonium Erholung. Die im Abschnitt Ergebnisse vorgestellt Berechnungen liefern die Parameter für die Bewertung der Systemleistung. Die biologischen und elektrochemische Systeme ähneln in Aufbau und Funktion. Der Hauptunterschied zwischen den zwei Systemen ist die Wahl eines festen Strom für die elektrochemische Zelle gegenüber einem festen Anodenpotential für die bio-elektrochemischen E...

Rückgewinnung von Wertstoffen aus Abwasser gewinnt an Bedeutung als wertvolle Ressourcen knapp und die Behandlung ohne Rückgewinnung werden nur einen Preis. Abwasser enthält sowohl Energie und Nährstoffe, die wiederhergestellt werden können, und Nährstoffrückgewinnung kann helfen, den Produktionskreislauf 1 zu schließen. Rückgewinnung von Energie durch anaerobe Vergärung ist ein gut etabliertes Verfahren, während die Rückgewinnung von Nährstoffen ist weniger verbreitet. Verwertung von Nährstoffen aus der flüssigen Abfallströmen, wie Urin und Dung wurde umfassend untersucht, beispielsweise durch die Produktion von Struvit und direkte Ammoniakstrippung 2,3. Die Notwendigkeit einer chemischen Zusatz ist jedoch ein Nachteil dieser Verfahren 4. Hier präsentieren wir eine Technik zur Gewinnung von kationischen Nährstoffen aus Abfallströmen, einschließlich Kalium und Ammonium. Die kationische Form dieser Nährstoffe ermöglicht die Wiederherstellung unter Verwendung einer ionenselektiven Membran, die in einem elektrochemischen System. In diesem Fall wird die electrochemical-System besteht aus einer Anodenkammer (wo Oxidation stattfindet), eine Kathodenkammer (wo die Reduktion stattfindet) und eine ionenselektive Membran, die Räume trennen. Eine Spannung wird an die Zelle angelegt, um einen Stromfluss von der Anode zur Kathode zu erzeugen. Diese Spannung kann durch eine externe Energiequelle, um Wasser Oxidations- und Reduktionsreaktionen fahren erzeugt werden. Alternativ kann die anodische Oxidation, beispielsweise aus organischen Verbindungen, können durch elektro Bakterien, weniger Leistung benötigt, katalysiert werden. Um die Schaltung für den Ladungsausgleich zu schließen und zu halten, muß ein geladener Spezies zwischen den Elektroden für jeden erzeugten Elektronen migrieren. Ammoniumtransport aus der Anodenkammer in die Kathodenkammer durch eine Kationenaustauschmembran (CEM) können so kompensiert den Fluss der Elektronen 4,5. Die hier vorgestellte Technik entfernt nicht nur Ammonium aus Abfallströmen, sondern ermöglicht auch die Erholung. Gesamtammoniakstickstoff (TAN) im Gleichgewicht sowohl ammon bestehtium (NH 4 +) und Ammoniak (NH 3), und ist abhängig von pH-Wert und Temperatur 6. NH 4 + ist reichlich durch hohe TAN Konzentration und in der Nähe von neutralem pH-Wert in der Anodenkammer und diese positiv geladene Spezies kann daher durch den Strom über die CEM in den Kathodenraum gefahren werden zur Verfügung. Der Strom treibt die Reduktion von Wasser an der Kathode, was zu der Erzeugung von Hydroxidionen und Wasserstoffgas. Die TAN Gleichgewicht verschiebt sich nahezu 100% NH 3 durch den hohen pH-Wert in der Kathodenkammer (&gt; 10,0). NH 3 ist ein Gas, das leicht durch Luftzirkulation von der Destillationseinheit in die Absorptionskolonne, wo er eingeschlossen und in einer Säurelösung konzentriert übertragen werden kann. Diese Technologie hat das Potenzial, Ammonium Toxizität während der anaeroben Vergärung von N-reichen Strömen wie Gülle zu verringern, wodurch die Energierückgewinnung aus diesen Abfallströmen, während gleichzeitigWiederherstellen Nährstoffe 4. Elektrochemische und bioelektrochemische Extraktion von Ammonium kann auch als Nährstoffrückgewinnungstechnik für Abfallströme mit hoher TAN Inhalte wie beispielsweise Urin, wodurch Kosten für Nährstoffentfernung in einer Kläranlage 7 Vermeidung angewendet werden. Die hier vorgestellte Protokoll kann als Basis für viele verschiedene elektrochemische und bioelektrochemische Experimenten dienen, wie wir eine modulare Reaktor. Verschiedene Elektrodenarten, Membranen und Rahmenstärken können kombiniert werden, wie in der nachstehenden Protokoll erläutert. Das Ziel des Protokolls ist es, ein Mittel für den Vergleich des elektrochemischen Ammonium Verwertung und bioelektrochemische Ammoniumrückgewinnung unter Verwendung einer Elektrolysezelle bereitzustellen. Die Systeme sind in Bezug auf die Extraktionseffizienz, Stromaufnahme und Reproduzierbarkeit bewertet.

<table border="0" cellpadding="0" cellspacing="0" width="876">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Name of Material/ Equipment</td>
			<td style="width:192px;">Company</td>
			<td style="width:301px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Carbon Felt 3.18 mm Thick&#160;</td>
			<td style="width:192px;">Alfa Aesar</td>
			<td style="width:301px;">ALFA43199</td>
			<td>Used as bioanode, 110 mm x 110 mm</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Ti electrode coated with Ir MMO&#160;</td>
			<td style="width:192px;">Magneto Special Anodes (The Netherlands)</td>
			<td style="width:301px;"></td>
			<td>Used as stable anode for electrochemical tests</td>
		</tr>
		<tr height="73">
			<td height="73" style="height:74px;width:216px;">Stainless steel mesh</td>
			<td style="width:192px;">Solana (Belgium)</td>
			<td style="width:301px;">RVS 554/64: material AISI 316L, mesh width: 564 micron, wire thickness: 140 micron, mesh number: 36,6</td>
			<td>Used as cathode, 110 mm x 110 mm</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:216px;">Stainless steel plate</td>
			<td style="width:192px;">Solana (Belgium)</td>
			<td style="width:301px;">inox 304 sheet, thickness: 0,5mm</td>
			<td>Used as current collector for the bioanode</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ag/AgCl Reference Electrode</td>
			<td style="width:192px;">Bio-Logic (France)</td>
			<td style="width:301px;">A-012167 RE-1B</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Potentiostat (VSP Multipotentiostat)&#160;</td>
			<td style="width:192px;">Bio-Logic (France)</td>
			<td style="width:301px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">EC Lab</td>
			<td style="width:192px;">Bio-Logic (France)</td>
			<td style="width:301px;"></td>
			<td>software for performing electrochemistry measurements</td>
		</tr>
		<tr height="44">
			<td height="44" style="height:44px;width:216px;">Cation Exchange Membrane</td>
			<td style="width:192px;">Membranes International (USA)</td>
			<td style="width:301px;">Ultrex CMI-7000</td>
			<td>Pretreated according to the manufacturers&#39; instructions</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Turbulence Promotor mesh</td>
			<td style="width:192px;">ElectroCell Europe A/S (Tarm, Denmark)</td>
			<td style="width:301px;">EPC20432-PP-2</td>
			<td>spacer material, 110 mm x 110 mm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Connectors</td>
			<td style="width:192px;">Serto</td>
			<td style="width:301px;">1,281,161,120</td>
			<td>Other sizes possible, dependant on tubing type and size of holes in frames</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Strip and absorption column</td>
			<td style="width:192px;"></td>
			<td style="width:301px;"></td>
			<td>In house design</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tubing</td>
			<td style="width:192px;">Masterflex</td>
			<td style="width:301px;">HV-06404-16</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Gas bag</td>
			<td style="width:192px;">Keika Ventures</td>
			<td style="width:301px;"></td>
			<td>Kynar gas bag with Roberts valve</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Rashig Rings</td>
			<td style="width:192px;">Glasatelier Saillart (Belgium)</td>
			<td style="width:301px;">Raschig rings 4 x 4 mm</td>
			<td>Put inside the strip and absorption column to improve the air/liquid contact. Available with many suppliers</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Rubber sheet</td>
			<td style="width:192px;"></td>
			<td style="width:301px;"></td>
			<td>Cut to fit on the perspex frames</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Perspex reactor frames</td>
			<td style="width:192px;">Vlaeminck, Beernem</td>
			<td style="width:301px;"></td>
			<td>In-house design, see tab &#34;reactor frames&#34; in this file</td>
		</tr>
	</tbody>
</table>

electrochemically and bioelectrochemically induced ammonium recovery

Streams such as urine and manure can contain high levels of ammonium, which could be recovered for reuse in agriculture or chemistry. The extraction of ammonium from an ammonium-rich stream is demonstrated using an electrochemical and a bioelectrochemical system. Both systems are controlled by a potentiostat to either fix the current (for the electrochemical cell) or fix the potential of the working electrode (for the bioelectrochemical cell). In the bioelectrochemical cell, electroactive bacteria catalyze the anodic reaction, whereas in the electrochemical cell the potentiostat applies a higher voltage to produce a current. The current and consequent restoration of the charge balance across the cell allow the transport of cations, such as ammonium, across a cation exchange membrane from the anolyte to the catholyte. The high pH of the catholyte leads to formation of ammonia, which can be stripped from the medium and captured in an acid solution, thus enabling the recovery of a valuable nutrient. The flux of ammonium across the membrane is characterized at different anolyte ammonium concentrations and currents for both the abiotic and biotic reactor systems. Both systems are compared based on current and removal efficiencies for ammonium, as well as the energy input required to drive ammonium transfer across the cation exchange membrane. Finally, a comparative analysis considering key aspects such as reliability, electrode cost, and rate is made.
This video article and protocol provide the necessary information to conduct electrochemical and bioelectrochemical ammonia recovery experiments. The reactor setup for the two cases is explained, as well as the reactor operation. We elaborate on data analysis for both reactor types and on the advantages and disadvantages of bioelectrochemical and electrochemical systems.

Chronoamperometrie resultiert aus Bioreaktor Die Chronoamperometrie Ergebnisse nach Gleichung 1 berechnet wird, zeigen eine typische Kurve für einen kontinuierlichen Reaktor (Abbildung 4). Zu Beginn des Experiments wurden die Anode und die Kathode im Umluftbetrieb betrieben. Dies ermöglicht einen Biofilm zu entwickeln und den Beginn der aktuellen Produktion. Nach 5 Tagen Betrieb die Stromdichte ein Maximum erreicht, gefolgt von einer Abnahme in der laufend...

Watch this Scientific Journal Video about Electrochemically and Bioelectrochemically Induced Ammonium Recovery at JoVE.com

Electrochemically and Bioelectrochemically Induced Ammonium Recovery

We demonstrate the extraction of ammonium from an ammonium-rich stream using an electrochemical and a bioelectrochemical system. The reactor setup, operation and data analysis are discussed.

Elektrochemisch und Bioelectrochemically Induzierte Ammonium Erholung

Streams such as urine and manure can contain high levels of ammonium, which could be recovered for reuse in agriculture or chemistry. The extraction of ...

electrochemically-and-bioelectrochemically-induced-ammonium-recovery

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Chemistry

Chemical Equilibrium

SCIENTISTS IN ACTION

12.6K Aufrufe.  Ghent University. We demonstrate the extraction of ammonium from an ammonium-rich stream using an electrochemical and a bioelectrochemical system. The reactor setup, operation and data analysis are discussed. 

Serie: Electrochemically and Bioelectrochemically Induced Ammonium Recovery

Dependence of Laser-induced Breakdown Spectroscopy Results on Pulse Energies and Timing Parameters Using Soil Simulants

The dependence of some LIBS detection capabilities on lower pulse energies (&lt;100 mJ) and timing parameters were examined using synthetic silicate samples. These samples were used as simulants for soil and contained minor and trace elements commonly found in soil at a wide range of concentrations. For this study, over 100 calibration curves were prepared using different pulse energies and timing parameters; detection limits and sensitivities were determined from the calibration curves. Plasma temperatures were also measured using Boltzmann plots for the various energies and the timing parameters tested. The electron density of the plasma was calculated using the full-width half maximum (FWHM) of the hydrogen line at 656.5 nm over the energies tested. Overall, the results indicate that the use of lower pulse energies and non-gated detection do not seriously compromise the analytical results. These results are very relevant to the design of field- and person-portable LIBS instruments.

LIBS detection capabilities on soil simulants were tested using a range of pulse energies and timing parameters. Calibration curves were used to determine detection limits and sensitivities for different parameters. Generally, the results showed that there was not a significant reduction in detection capabilities using lower pulse energies and non-gated detection.

Abhängigkeit der Laser-induzierten Breakdown Spectroscopy Ergebnisse auf Pulsenergien und Timing-Parameter Mit Boden Simulanten

The  dependence of some LIBS detection capabilities on lower pulse energies (&lt;100  mJ) and timing parameters were examined using synthetic silicate ...

Forschung

Chemie

Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid phase by using combinatorial chemistry. One of the most well studied classes of peptidomimetics is peptoids. Peptoids are easy to synthesize and have been shown to be proteolysis-resistant and cell-permeable. Over the past decade, many useful protein ligands have been identified through screening of peptoid libraries. However, most of the ligands identified from peptoid libraries do not display high affinity, with rare exceptions. This may be due, in part, to the lack of chiral centers and conformational constraints in peptoid molecules. Recently, we described a new synthetic route to access peptide tertiary amides (PTAs). PTAs are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. With side chains on both &#945;-carbon and main chain nitrogen atoms, the conformation of these molecules are greatly constrained by sterical hindrance and allylic 1,3 strain. (Figure 1) Our study suggests that these PTA molecules are highly structured in solution and can be used to identify protein ligands. We believe that these molecules can be a future source of high-affinity protein ligands. Here we describe the synthetic method combining the power of both split-and-pool and sub-monomer strategies to synthesize a sample one-bead one-compound (OBOC) library of PTAs.

Peptide tertiary amides (PTAs) are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. Here we describe a synthetic method which combines&#160;both split-and-pool and sub-monomer strategies to synthesize a one-bead one-compound library of PTAs.

Split-and-Pool-Synthese und Charakterisierung von Peptid-Amid-Tertiär-Bibliothek

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid ...

Preparation of Mica and Silicon Substrates for DNA Origami Analysis and Experimentation

The designed nature and controlled, one-pot synthesis of DNA origami provides exciting opportunities in many fields, particularly nanoelectronics. Many of these applications require interaction with and adhesion of DNA nanostructures to a substrate. Due to its atomically flat and easily cleaned nature, mica has been the substrate of choice for DNA origami experiments. However, the practical applications of mica are relatively limited compared to those of semiconductor substrates. For this reason, a straightforward, stable, and repeatable process for DNA origami adhesion on derivatized silicon oxide is presented here. To promote the adhesion of DNA nanostructures to silicon oxide surface, a self-assembled monolayer of 3-aminopropyltriethoxysilane (APTES) is deposited from an aqueous solution that is compatible with many photoresists. The substrate must be cleaned of all organic and metal contaminants using Radio Corporation of America (RCA) cleaning processes and the native oxide layer must be etched to ensure a flat, functionalizable surface. Cleanrooms are equipped with facilities for silicon cleaning, however many components of DNA origami buffers and solutions are often not allowed in them due to contamination concerns. This manuscript describes the set-up and protocol for in-lab, small-scale silicon cleaning for researchers who do not have access to a cleanroom or would like to incorporate processes that could cause contamination of a cleanroom CMOS clean bench. Additionally, variables for regulating coverage are discussed and how to recognize and avoid common sample preparation problems is described.

Reproducible cleaning processes for substrates used in DNA origami research are described, including bench-top RCA cleaning and derivatization of silicon oxide. Protocols for surface preparation, DNA origami deposition, drying parameters, and simple experimental set-ups are illustrated.

Herstellung von Mica und Siliziumsubstraten für die DNA-Origami-Analyse und Experimentieren

The designed nature and controlled, one-pot synthesis of DNA origami provides exciting opportunities in many fields, particularly nanoelectronics. Many of ...

Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar concentration forming hydrophobic cores surrounded by hydrophilic shells in aqueous environments. The core of these micelles can be utilized to load hydrophobic, poorly water soluble drugs like docetaxel (DTX) and everolimus (EVR). Systematic characterization of the micelle structure and drug loading capabilities are important before in vitro and in vivo studies can be conducted. The goal of the protocol described herein is to provide the necessary characterization steps to achieve standardized micellar products. DTX and EVR have intrinsic solubilities of 1.9 and 9.6 &#181;g/ml respectively Preparation of these micelles can be achieved through solvent casting which increases the aqueous solubility of DTX and EVR to 1.86 and 1.85 mg/ml, respectively. Drug stability in micelles evaluated at room temperature over 48 hr indicates that 97% or more of the drugs are retained in solution. Micelle size was assessed using dynamic light scattering and indicated that the size of these micelles was below 50 nm and depended on the molecular weight of the polymer. Drug release from the micelles was assessed using dialysis under sink conditions at pH 7.4 at 37 oC over 48 hr. Curve fitting results indicate that drug release is driven by a first order process indicating that it is diffusion driven.

The goal of this protocol is to describe the preparation and characterization of physically entrapped, poorly water soluble drugs in micellar drug delivery systems composed of amphiphilic block copolymers.

Herstellung und Charakterisierung von Einzel-und Multi-Wirkstoff beladen Körperlich Eingeschlossene Polymermicellen

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar ...

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes

Enzyme catalysis evolved in an aqueous environment. The influence of solvent dynamics on catalysis is, however, currently poorly understood and usually neglected. The study of water dynamics in enzymes and the associated thermodynamical consequences is highly complex and has involved computer simulations, nuclear magnetic resonance (NMR) experiments, and calorimetry. Water tunnels that connect the active site with the surrounding solvent are key to solvent displacement and dynamics. The protocol herein allows for the engineering of these motifs for water transport, which affects specificity, activity and thermodynamics. By providing a biophysical framework founded on theory and experiments, the method presented herein can be used by researchers without previous expertise in computer modeling or biophysical chemistry. The method will advance our understanding of enzyme catalysis on the molecular level by measuring the enthalpic and entropic changes associated with catalysis by enzyme variants with obstructed water tunnels. The protocol can be used for the study of membrane-bound enzymes and other complex systems. This will enhance our understanding of the importance of solvent reorganization in catalysis as well as provide new catalytic strategies in protein design and engineering.

Channels for the transportation of water molecules in enzymes influence active site solvation and catalysis. Herein we present a protocol for the engineering of these additional catalytic motifs based on in silico computer modeling and experiments. This will enhance our understanding of the influence of solvent dynamics on enzyme catalysis.

Entwirren Entropic Reaktionsbeschleunigung durch Solvent Dynamics in Membranenzyme induziert

Enzyme catalysis evolved in an aqueous environment. The influence of solvent dynamics on catalysis is, however, currently poorly understood and usually ...

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores.

The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.

Synthese, Charakterisierung und Funktionalisierung von Hybrid Au / CdS und Au / ZnS Kern / Schale-Nanopartikel

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large ...

Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates

Functions of clusters in nano or sub-nano scale significantly depend on not only kinds of their components but also arrangements, or symmetry, of their components. Therefore, the arrangements in the clusters have been precisely characterized, especially for metal complexes. Contrary to this, characterizations of molecular arrangements in supramolecular clusters composed of organic molecules are limited to a few cases. This is because construction of the supramolecular clusters, especially obtaining a series of the supramolecular clusters, is difficult due to low stability of non-covalent bonds compare to covalent bonds. From this viewpoint, utilization of organic salts is one of the most useful strategies. A series of the supramolecules could be constructed by combinations of a specific organic molecule with various counter ions. Especially, primary ammonium carboxylates are suitable as typical examples of supramolecules because various kinds of carboxylic acids and primary amines are commercially available, and it is easy to change their combinations. Previously, it was demonstrated that primary ammonium triphenylacetates using various kinds of primary amines specifically construct supramolecular clusters, which are composed of four ammoniums and four triphenylacetates assembled by charge-assisted hydrogen bonds, in crystals obtained from non-polar solvents. This study demonstrates an application of the specific construction of the supramolecular clusters as a strategy to conduct systematical symmetric study for clarification of correlations between molecular arrangements in supramolecules and kinds and numbers of their components. In the same way with binary salts composed of triphenylacetates and one kind of primary ammoniums, ternary organic salts composed of triphenylacetates and two kinds of ammoniums construct the supramolecular clusters, affording a series of the supramolecular clusters with various kinds and numbers of the components.

This article describes construction of a series of hydrogen-bonding supramolecular clusters in crystals using primary ammonium triphenylacetates, which are recrystallized from non-polar solvents. This selective construction of the supramolecular clusters leads to effective systematical symmetric studies about a correlation between the supramolecular clusters and their components.

Ausbau und Systematische Symmetric Studien auf eine Serie von supramolekularen Cluster mit binären oder ternären Ammonium Triphenylacetates

Functions of clusters in nano or sub-nano scale significantly depend on not only kinds of their components but also arrangements, or symmetry, of their ...

Green and Low-cost Production of Thermally Stable and Carboxylated Cellulose Nanocrystals and Nanofibrils Using Highly Recyclable Dicarboxylic Acids

Here we demonstrate potentially low cost and green productions of high thermally stable and carboxylated cellulose nanocrystals (CNCs) and nanofibrils (CNF) from bleached eucalyptus pulp (BEP) and unbleached mixed hardwood kraft pulp (UMHP) fibers using highly recyclable dicarboxylic solid acids. Typical operating conditions were acid concentrations of 50 - 70 wt% at 100 &#176;C for 60 min and 120 &#176;C (no boiling at atmospheric pressure) for 120 min, for BEP and UMHP, respectively. The resultant CNCs have a higher thermal degradation temperature than their corresponding feed fibers and carboxylic acid group content from 0.2 - 0.4 mmol/g. The low strength (high pKa of 1.0 - 3.0) of organic acids also resulted in CNCs with both longer lengths of approximately 239 - 336 nm and higher crystallinity than CNCs produced using mineral acids. Cellulose loss to sugar was minimal. Fibrous cellulosic solid residue (FCSR) from the dicarboxylic acid hydrolysis was used to produce carboxylated CNFs through subsequent mechanical fibrillation with low energy input.

Here we demonstrate a novel method for green and sustainable productions of highly thermally stable and carboxylated cellulose nanocrystals (CNC) and nanofibrils (CNF) using highly recyclable solid dicarboxylic acids.

Grüne und Low-Cost-Produktion von thermisch stabil und carboxylierte Cellulose-Nanokristalle und Nanofibrillen Mit Recycelbares Dicarbonsäuren

Here we demonstrate potentially low cost and green productions of high thermally stable and carboxylated cellulose nanocrystals (CNCs) and nanofibrils ...

Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy

Water/solid interfaces are ubiquitous and play a key role in many environmental, biophysical, and technological processes. Resolving the internal structure and probing the hydrogen-bond (H-bond) dynamics of the water molecules adsorbed on solid surfaces are fundamental issues of water science, which remains a great challenge owing to the light mass and small size of hydrogen. Scanning tunneling microscopy (STM) is a promising tool for attacking these problems, thanks to its capabilities of sub-&#197;ngstr&#246;m spatial resolution, single-bond vibrational sensitivity, and atomic/molecular manipulation. The designed experimental system consists of a Cl-terminated tip and a sample fabricated by dosing water molecules in situ onto the Au(111)-supported NaCl(001) surfaces. The insulating NaCl films electronically decouple the water from the metal substrates, so the intrinsic frontier orbitals of water molecules are preserved. The Cl-tip facilitates the manipulation of the single water molecules, as well as gating the orbitals of water to the proximity of Fermi level (EF) via tip-water coupling. This paper outlines the detailed methods of submolecular resolution imaging, molecular/atomic manipulation, and single-bond vibrational spectroscopy of interfacial water. These studies open up a new route for investigating the H-bonded systems at the atomic scale.

Here, we present a protocol to investigate the structure and dynamics of interfacial water at the atomic scale, in terms of submolecular resolution imaging, molecular manipulation, and single-bond vibrational spectroscopy.

Erforschung der Struktur und Dynamik von Grenzflächen Wasser mit Scanning Tunneling-Mikroskopie und Spektroskopie

Water/solid interfaces are ubiquitous and play a key role in many environmental, biophysical, and technological processes. Resolving the internal ...

Constructing Thioether/Vinyl Sulfide-tethered Helical Peptides Via Photo-induced Thiol-ene/yne Hydrothiolation

Here, we describe a detailed protocol for the preparation of thioether-tethered peptides using on-resin intramolecular/intermolecular thiol-ene hydrothiolation. In addition, this protocol describes the preparation of vinyl-sulfide-tethered peptides using in-solution intramolecular thiol-yne hydrothiolation between amino acids that possess alkene/alkyne side chains and cysteine residues at i, i+4 positions. Linear peptides were synthesized using a standard Fmoc-based solid-phase peptide synthesis (SPPS). Thiol-ene hydrothiolation is carried out using either an intramolecular thio-ene reaction or an intermolecular thio-ene reaction, depending on the peptide length. In this research, an intramolecular thio-ene reaction is carried out in the case of shorter peptides using on-resin deprotection of the trityl groups of cysteine residues following the complete synthesis of the linear peptide. The resin is then set to UV irradiation using photoinitiator 4-methoxyacetophenone (MAP) and 2-hydroxy-1-[4-(2-hydroxyethoxy)-phenyl]-2-methyl-1-propanone (MMP). The intermolecular thiol-ene reaction is carried out by dissolving Fmoc-Cys-OH in an N,N-dimethylformamide (DMF) solvent. This is then reacted with the peptide using the alkene-bearing residue on resin. After that, the macrolactamization is carried out using benzotriazole-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBop), 1-hydroxybenzotriazole (HoBt), and 4-Methylmorpholine (NMM) as activation reagents on the resin. Following the macrolactamization, the peptide synthesis is continued using standard SPPS. In the case of the thio-yne hydrothiolation, the linear peptide is cleaved from the resin, dried, and subsequently dissolved in degassed DMF. This is then irradiated using UV light with photoinitiator 2,2-dimethoxy-2-phenylacetophenone (DMPA). Following the reaction, DMF is evaporated and the crude residue is precipitated and purified using high-performance liquid chromatography (HPLC). These methods could function to simplify the generation of thioether-tethered cyclic peptides due to the use of the thio-ene/yne click chemistry that possesses superior functional group tolerance and good yield. The introduction of thioether bonds into peptides takes advantage of the nucleophilic nature of cysteine residues and is redox-inert relative to disulfide bonds.

We present a protocol for the construction of thioether/vinyl sulfide-tethered helical peptides using photo-induced thiol-ene/thiol-yne hydrothiolation.