Conventional Anion Research Articles

Construction of poly (styrene-divinylbenzene)@tris(4-aminophenyl)amine-p-phthalaldehyde-triethylenetetramine core-shell microspheres for the preparation of ion chromatography stationary phase

Core-shell composite microspheres are increasingly favored for the development of stationary phases due to their ability to integrate the monodispersity of inner core with the functional versatility of outer shell. In this study, poly(styrene-divinylbenzene)@(tris(4-aminophenyl)amine-p-phthalaldehyde-triethylenetetramine) (PS-DVB@TAPA-PPA-TETA) core-shell composite microspheres were constructed via an amine-aldehyde condensation reaction. The resultant microspheres were subsequently quaternized using the residual amine groups of TETA in the shell to create an effective anion-exchange stationary phase. The composite microspheres were characterized by SEM, FTIR, N2 adsorption-desorption experiment, et al. According to the results, the surface of PS-DVB microspheres was wholly covered by TAPA-PPA-TETA. The obtained PS-DVB@TAPA-PPA-TETA exhibited good reactivity, mechanical and chemical stability. The customized column exhibited good separation performance for seven conventional anions, five organic acids and three carbohydrates. The results demonstrate that PS-DVB@TAPA-PPA-TETA is a highly suitable material for the preparation of ion chromatographic stationary phase, exhibiting exceptional chemical stability and robust chromatographic performance in practical application. Finally, the customized column was successfully utilized for the determination of phosphate in waste acid sample.

Shielding Fluoride Ion Basicity through Diurea Coordination for Nonaqueous Fluoride Shuttle Batteries.

The strong basicity of fluoride ions leads to detrimental nucleophilic attack on organic components in the electrolytes, such as β-hydrogen elimination reactions with organic cations and solvents, converting "naked" F- into corrosive and unstable bifluoride (HF2-) ions. These reactions significantly constrain the choice of suitable solvents and salts to develop electro(chemical) stable fluoride ion electrolytes. In this work, we replaced the triple water ligands typically present in industrialorganic fluoride salts with dual 1,3-diphenylurea (DPU) coordination via hydrogen bonding interaction. This modification successfully suppressed the Lewis basicity of fluoride ions, providing long-term chemical stability (over 1000 hours) acrossa wide range of aprotic solvents, a broadened electrochemical stability window (-2.5 ~ 0.9 V vs. Ag+/Ag) and high ionic conductivity (1.7 mS cm-1) at room temperature. Additionally, the weaker hydrogen bonding in F--DPU coordination, compared to the conventional boron-based anion acceptor (AA) strategy that relies on intensive Lewis acid-base interactions, facilitates faster (de)fluorination kineticsat the electrode. The proposed room temperature fluoride ion batteries sustain improved electrochemical performance by pairing with the Pb-PbF2 anode and BiF3 or Ag cathode.

Unveiling the synergistic mechanism of Co-Cu catalysts for efficient oxygen evolution reactions

The development of highly active electrocatalysts for Oxygen Evolution Reactions (OER) is critical in the field of energy conversion and storage. Among potential candidates, diatomic catalysts have demonstrated the potential to outperform monoatomic counterparts, though comprehensive studies on their reaction mechanisms remain limited. In this study, a Co-Cu diatomic catalyst was computationally designed using density functional theory (DFT), and four reaction pathways involving multiple intermediates (*O, *OH, *OOH, *2OH, *O + *OH) were calculated. The results indicate that the Co-Cu diatomic catalyst exhibits superior catalytic performance on pathway II (H2O → *OH → *2OH → *OOH → O2) with an overpotential of 0.27 V, overcoming the limitations imposed by the active site of conventional anion exchange membrane (AEM) catalysts. The high catalytic activity is attributed to the synergistic interaction between the metal atoms, bypassing the high-energy barrier step typically observed in conventional pathways. In this mechanism, the Cu d-band center is close to the Fermi energy level, enhancing electron transfer, while Co provides a stable adsorption site and effectively regulates the adsorption and conversion of reaction intermediates. These findings offer new strategies for the rational synthesis of bimetallic catalysts.

Construction of amine-rich coating utilizing amine curing reaction of triglycidyl isocyanate with triethylenetetramine on the surface of poly(styrene-divinylbenzene) microspheres for preparation of anion exchange stationary phase.

Epoxy resins, as important thermosetting polymers, exhibit excellent adhesion to various substrates. In view of this, reticulate coating of triglycidyl isocyanate with triethylenetetramine was introduced onto the surface of poly(styrene-divinylbenzene) utilizing amine curing reaction to obtain poly(styrene-divinylbenzene)@triglycidyl isocyanate-triethylenetetramine composite microspheres. The amino groups and epoxy groups of triglycidyl isocyanate-triethylenetetramine endowed poly(styrene-divinylbenzene) with good reactivity, which could be quaternized under mild conditions to obtain an anion exchange chromatographic stationary phase. The quaternized poly(styrene-divinylbenzene)@triglycidyl isocyanate-triethylenetetramine was characterized by scanning electron microscope, Fourier-transform infrared spectroscopy, N2 adsorption-desorption experiment, etal. The chromatographic performance of the customized column was evaluated by separating seven conventional anions, organic weak acids, and carbohydrates. Poly(styrene-divinylbenzene)@triglycidyl isocyanate-triethylenetetramine possesses the uniform size of poly(styrene-divinylbenzene) microspheres and good reactivity of triglycidyl isocyanate-triethylenetetramine, which offers a flexible strategy for the preparation of anion exchange stationary phase. The column exhibits excellent chemical and mechanical stability and chromatographic performance. Finally, the column was successfully applied for the determination of nitrite in pickles.

(Invited) Accelerated Three Electrode Cell (TEC) Testing for Optimizing Electrodes in Conventional Alkaline Electrolysis and Anion Exchange Membrane Water Electrolysis

The merging of conventional Alkaline Electrolysis (AEL) and Proton Exchange Membrane Water Electrolysis (PEMWE) has led to the development of Anion Exchange Membrane Water Electrolysis (AEMWE). At this juncture, both AEL and AEMWE technologies offer an advantage over PEMWE as they do not require critical raw components and materials (CRM).[1] While AEMWE has demonstrated higher efficiencies than AEL with thin membranes and low concentrations of KOH, AEL technology addresses the significant stability challenge posed by anionic membranes by employing KOH electrolyte with novel zero-gap configurations, relying on stable diaphragms. Consequently, AEL technology offers a more cost-effective and scalable solution for current large-scale hydrogen production, while AEMWE remains a promising solution that will most probably be implemented on larger scales in the following decade. In any case, both technologies require more efficient and scalable catalysts for lowering the overall cell voltage of electrolyzers. Along this front, Matteco’s patented processes stand at the forefront of manufacturing highly active and stable catalysts and electrodes crafted from Layered Double Hydroxides (LDHs), which have gained increasing attention due to their low overpotentials and promising stabilities.[2] However, Beyond the intrinsic qualities of the catalysts, a myriad of factors —electrolyte concentration, substrate type, and the catalyst/substrate interface— play pivotal roles in determining electrolyzer activity and stability, forming a complex multiparameter matrix that will condition the final performance of the electrolysers. Contrary to three-electrode catalyst testing conditions for PEMWE, in which acids are used to simulate the real conditions of electrolyzers, AEL- and AEMWE-TEC testing can be performed using realistic conditions, from 0.1 to 7M alkaline electrolytes.Thus, this work presents the results of Matteco’s accelerated TEC testing to decipher the complex multiparameter alkaline electrolysis matrix, obtaining the most promising catalysts, substrates, and processes that deliver the best performances and stabilities of AEL and AEMWE technologies.

Diagnostic accuracy of the anion gap to identify toxic lithium concentrations: a single-center retrospective observational study

Introduction Lithium exhibits a narrow margin between therapeutic doses and toxic blood concentrations, which can pose a substantial risk of toxic effects. Reportedly, lithium toxicity may be associated with a reduced anion gap; however, the precise relationship remains unclear. This study examined several different anion gap calculation methods to detect toxic lithium concentrations without directly measuring blood lithium concentrations. Methods Our retrospective study analyzed blood samples collected for lithium concentration measurements. The anion gap was determined using three different methods, both with and without albumin and lactate concentration corrections. Samples were categorized into two groups based on lithium concentration (<1.5 or ≥1.5 mmol/L), and anion gap values were compared. Correlation and logistic regression analyses were used to assess the relationship between each anion gap indicator and lithium concentration. Receiver operating characteristic curves were used for diagnostic analysis. Results Overall, 24 measurements were collected, with 41.7% of samples falling within the toxic range. The high-lithium concentration group exhibited significantly smaller anion gaps. Correlation and logistic regression analyses revealed a significant association between anion gap values and lithium concentrations. Areas under the receiver operating characteristic curve were: conventional anion gap 0.77 (95% CI: 0.55–0.94); albumin-corrected anion gap 0.85 (95% CI: 0.66–1.00); and both albumin- and lactate-corrected anion gap 0.86 (95% CI: 0.66–1.00). Discussion The anion gap is calculated as the difference between measured cations and anions. Accumulation of lithium (a cation) may decrease measured cations and decrease the calculated anion gap. Abnormal albumin and lactate concentrations may also alter the anion gap and affect its usefulness as a diagnostic marker for elevated serum lithium concentrations. A negative likelihood ratio of 0.1 suggests that the anion gap might be valuable in excluding toxicity. Conclusions The corrected anion gap, accounting for albumin and lactate concentrations, may be beneficial in suggesting the possibility of toxic lithium concentrations.

Improving anion exchange membrane fuel cell performance via enhanced ionomer–carbon interaction in cathode catalyst layers with carbon-supported Pt catalyst using a pyrene carboxyl acid coating

While there have been substantial strides in anion exchange membrane and ionomer, engineering the catalyst layers (CLs) of anion exchange membrane fuel cells (AEMFCs) is still an unexplored domain despite its significance. Conventional anion exchange ionomers (AEIs) tend to be locally agglomerated in the CLs due to their weak interaction with the carbon support of catalyst, resulting in pore clogging in the CLs. Herein, we report that the coating of pyrene carboxyl acid (PCA) on the carbon surface increases ionomer–carbon interaction. PCA has a strong interaction with carbon surface via π–π interaction and with AEI via coulombic interaction. The use of PCA prevents the aggregation of ionomer chains, leading to homogeneous ionomer distribution and meso-porous CL structure. Due to the expanded catalyst/ionomer interface and promoted O2 transport, PCA coating improves the electrochemical performance of AEMFC. Controlling the ionomer–carbon interaction opens a new avenue for realizing high-performance AEMFCs.

A four-fold interpenetrated MOF for efficient perrhenate/pertechnetate removal from alkaline nuclear effluents

The sequestration of 99Tc represents one of the most challenging tasks in nuclear waste decontamination. In the event of a radioactive waste leak, 99TcO4– (a main form of 99Tc) would spread into the groundwater, a scenario difficult to address with conventional anion exchange materials like resin and inorganic cationic sorbents. Herein, we present a nickel(II) metal-organic framework (MOF), TNU-143, featuring 3D four-fold interpenetrated networks. TNU-143 exhibits efficient ReO4– (a nonradioactive analogue of 99TcO4–) removal with fast anion exchange kinetics (<1 min), high sorption capacity (844 mg/g for ReO4–), and outstanding selectivity over common anions. More importantly, TNU-143 shows superior stability in alkaline solution and can remove 91.6% ReO4– from simulated alkaline high-level waste (HLW) streams with solid-liquid ratio of 40 g/L. The uptake mechanism is elucidated by the single-crystal structure of TNU-143(Re), showing that ReO4– anions are firmly coordinated to nickel cation to result in a 2D layered structures. Density functional theory (DFT) calculations confirm the transformation from TNU-143 to TNU-143(Re) is a thermodynamically favorable process. This work presents a new approach to the removal of ReO4–/99TcO4– from alkaline nulcear fuel using MOF sorbents.

Preparation of a novel adsorbent with amino-rich carbon quantum dots for efficiently separating Zn(II) from Fe(II) in zinc deplating waste liquid

Zinc deplating waste liquid is considered hazardous due to the presence of heavy metal Zn(II) and hydrochloric acid, along with Fe(II). This study aims to develop a new adsorbent for efficient separation of zinc (II) from deplating waste liquid in a real factory. The novel adsorbent, PSCL-CQDs-NH2, was prepared by grafting home-made amino-rich carbon quantum dots (CQDs-NH2) onto a chloromethyl polystyrene resin matrix. It has been observed that amino groups can be protonated under strongly acidic conditions, enabling them to adsorb negatively charged Zn(II)-Cl complexes while repelling positively charged Fe(II)-Cl complexes. The grafted nano-size CQDs-NH2 can offer more adsorption positions to improve the adsorption properties. The results shown that PSCL-CQDs-NH2 presented higher Zn(II) adsorption capacity and better performance in separating Zn(II) from Fe(II) compared to the conventional anion exchange resin (717). At 298 K, PSCL-CQDs-NH2 showed a maximum Zn(II) adsorption capacity of 201.77 mg/g, and a selective Zn(II)/Fe(II) separation factor of 3033.72, which were 54.7% and 45.4 times higher than those of 717 resin. In the fixed bed adsorption process, PSCL-CQDs-NH2 exhibited 61.5% higher adsorption performance than 717 resin when treating actual zinc deplating waste liquid. Moreover, the water consumption during regeneration of PSCL-CQDs-NH2 is reduced by 10.3% compared to the 717 resin. These findings indicate that PSCL-CQDs-NH2 is an effective material for the treatment of industrial zinc deplating waste liquid.

Band engineering of layered oxyhalide photocatalysts for visible-light water splitting.

The band structure offers fundamental information on electronic properties of solid state materials, and hence it is crucial for solid state chemists to understand and predict the relationship between the band structure and electronic structure to design chemical and physical properties. Here, we review layered oxyhalide photocatalysts for water splitting with a particular emphasis on band structure control. The unique feature of these materials including Sillén and Sillén-Aurivillius oxyhalides lies in their band structure including a remarkably high oxygen band, allowing them to exhibit both visible light responsiveness and photocatalytic stability unlike conventional mixed anion compounds, which show good light absorption, but frequently encounter stability issues. For band structure control, simple strategies effective in mixed-anion compounds, such as anion substitution forming high energy p orbitals in accordance with its electronegativity, is not effective for oxyhalides with high oxygen bands. We overview key concepts for band structure control of oxyhalide photocatalysts such as lone-pair interactions and electrostatic interactions. The control of the band structure of inorganic solid materials is a crucial challenge across a wide range of materials chemistry fields, and the insights obtained by the development of oxyhalide photocatalysts are expected to provide knowledge for diverse materials chemistry.

Highly Fluorinated and Boron Containing Anion Derived Stable Anode and Cathode Interfaces for Long Cycle and High Voltage Sodium Metal Batteries

Sodium metal is a propitious anode for the development of next generation metal batteries owing to its low reduction potential (-2.71 V) and high theoretical capacity (1165 mAh g-1)1. Among various electrolytes, carbonate solvents can be useful to develop high voltage metal batteries with wide temperature range2. However, the aggressive reactivity of sodium metal in carbonate electrolytes lead to the formation of unstable solid electrolyte interface on the metal anode which renders poor long cycling performance to the battery3. In this work, we have fabricated thin and inorganic components (F and B rich) rich solid electrolyte interface (SEI) on Na metal anode and cathode electrolyte interface (CEI) on oxide-based cathode to improve long cycling stability of sodium metal battery. Here, fluorine (F) and boron (B) containing anion is compared with conventional hexafluorophosphate anion (PF6-) in binary carbonate solvent system (EC:EMC). The stable stripping/plating behaviour of both symmetric (Na/Na) and asymmetric cell (Al/Na) in case of F and B containing anion is found compared to the PF6 - anion.The excellent long-term cycling stability of full cell (Na/Na0.67Fe0.5Mn0.5O2) is further attributed to the improved electrochemical stability window and better aluminium passivation on employing F and B containing anion in the electrolyte system as compared to PF6 - anion. The dual role of F and B containing anion to form stable interfaces on both the anode and cathode side provides a pathway in the development of fluorinated electrolytes for high voltage sodium metal batteries.

Bipolar Membrane with Porous Anion Exchange Layer for Efficient and Long‐Term Stable Electrochemical Reduction of CO2 to CO

AbstractBipolar membranes in forward bias have the potential to address several challenges of alkaline zero‐gap CO2 electrolyzers. However, the inevitable gas evolution of CO2 at the membrane junction typically leads to delamination and failure of the membrane after a few hours, limiting its applicability in electrolyzers so far. In this work, a bipolar membrane with a perforated anion exchange layer is presented that allows the CO2 gas to flow back to the cathode and thus preventing accumulation of gas at the junction. This configuration for the first time enables stable operation of a forward bias bipolar membrane showing a degradation rate of 0.5 mV h−1 in a 200 h constant current hold at 100 mA cm−2 and 3.1 V. Highest reported energy efficiency of EECO = 39% and Faradaic efficiency of FECO = 96% at 200 mA cm−2 among forward bipolar membranes prove that the perforated membrane does not compromise efficiency. A maximum CO2 single‐pass conversion of 52% at 0.75 mLCO2 min−1 cm−2 and a low specific energy consumption of 665 kJ mol−1 CO2 shows that this concept is superior not only to other bipolar membranes in the literature, but potentially also to conventional anion exchange membrane‐based electrolyzers.

Construction of polydopamine-polyethyleneimine composite coating on the surface of poly (styrene–divinylbenzene) microspheres followed by quaternization for preparation of anion exchangers

As a mussel-inspired material, dopamine (DA) is widely applied for the surface modification of various bulk materials based on its self-polymerization properties. Whereas, polydopamine (PDA) modified poly (styrene–divinylbenzene) (PS-DVB) microsphere is still hard to be quaternized under mild conditions. In this work, polyethyleneimine (PEI) is selected as the comonomer to participate in the crosslinking with PDA to form PDA-PEI composite coating on the surface of PS-DVB microsphere. Then, PS-DVB@PDA-PEI microsphere is further quaternized utilizing PDA-PEI coating as the secondary functionalized platform to prepare anion exchanger. The anion exchanger is characterized by scanning electron microscope, fourier transform infrared spectroscopy, nitrogen adsorption–desorption measurement, X-ray photoelectron spectroscopy, elemental analysis, thermogravimetric analysis. The chromatographic performance is evaluated by separating seven conventional anions, organic weak acids, et. al. The results indicate that PDA-PEI shows higher reactivity than PDA due to the present of abundant amine groups. The introduce of PDA-PEI coating makes PS-DVB microspheres can be quaternized under mild conditions. The strategy presented here is very suitable for the preparation of anion exchangers.

Spectroscopy of Radicals, Clusters, and Transition States Using Slow Electron Velocity-Map Imaging of Cryogenically Cooled Anions

Slow electron velocity-map imaging of cryogenically cooled anions (cryo-SEVI) is a high-resolution variant of anion photoelectron spectroscopy that has been applied with considerable success over the years to the study of radicals, size-selected clusters, and transition states for unimolecular and bimolecular reactions. Cryo-SEVI retains the versatility of conventional anion photoelectron spectroscopy while offering sub-meV resolution, thereby enabling the resolution of vibrational structure in the photoelectron spectra of complex anions. This Feature Article describes recent experiments in our laboratory using cryo-SEVI, including a new research direction in which anions are vibrationally pre-excited with an infrared laser pulse prior to photodetachment.

Covalent organic framework membranes for acid recovery: The effect of charges

Acid recovery has drawn an intensive interest due to the tremendous consumption of acid chemicals in various industry applications, which produce large amounts of acidic wastewater. For conventional anion exchange membranes (AEMs) via diffusion dialysis, the low selectivity between H+ and monovalent cations restricts the precise recovery of acid. Herein, we develop a self-standing COF (TpTAPA) membrane with high stability both in the acid and base solutions. The as-prepared membrane exhibits excellent separation performance for H+ over other monovalent and multivalent cations, where the selectivities of H+/K+, H+/Na+, H+/Li+, H+/Mg2+, and H+/Fe2+ are 136, 143, 145, 608, and 1499, respectively. Whereafter, the membrane nanochannels are decorated with different charges, where the positively charged Q-TpTAPA nanochannels are beneficial for H+ transport and the negatively charged S-TpTAPA nanochannels are adverse for the transport of H+ compared with the pristine TpTAPA membrane. However, both negatively and positively charged nanochannels can increase the leakage of multivalent cations, resulting in the decline of H+ selectivity. These significant findings shed light on the design of high-efficiency nanoporous membranes for exquisite acid recovery from complex feed system.

Laser‐Triggered Vapor‐Phase Anion Exchange on All‐Inorganic Perovskites for Multicolor Patterns and Microfabrications

AbstractAnion exchange reaction is a facile postsynthesis approach to modulate the bandgaps of perovskites to meet the demands in full visible spectrum. However, conventional anion exchanges are usually conducted in solutions, limiting their applications in fabricating high‐quality blue‐emitting perovskites and multicolor fluorescent patterns. Herein, a laser‐triggered vapor‐phase anion exchange (LTVAE) method is developed to convert CsPbBr3 perovskites with different morphologies (nanocrystal films/solution, microcrystals, and microplatelets) into CsPb(BrxCl1‐x)3 and CsPb(BrxI1‐x)3 perovskites. Thus, the green fluorescence is converted into blue and red fluorescence. Moreover, the deep‐blue fluorescence obtained by LTVAE shows a high quantum yield (QY) of 67.2%. Based on the mask‐assistant LTVAE, multicolor fluorescent patterns are fabricated, which are very significant for anticounterfeit and multicolor displays. Furthermore, a polymer‐assistant LTVAE method is developed to improve the stability of the multicolor fluorescent patterns. More importantly, micro‐heterojunctions with two different fluorescent colors are successfully constructed on a single CsPbBr3 microplatelet, which paves the way for microfabrications.

Glass as a State of Matter—The “newer” Glass Families from Organic, Metallic, Ionic to Non-silicate Oxide and Non-oxide Glasses

OVERVIEWIn theory, any molten material can form a glass when quenched fast enough. Most natural glasses are based on silicates and for thousands of years only alkali/alkaline earth silicate and lead-silicate glasses were prepared by humankind. After exploratory glass experiments by Lomonosov (18th ct) and Harcourt (19th ct), who introduced 20 more elements into glasses, it was Otto Schott who, in the years 1879–1881, melted his way through the periodic table of the elements so that Ernst Abbe could study all types of borate and phosphate glasses for their optical properties. This research also led to the development of the laboratory ware, low alkali borosilicate glasses. Today, not only can the glass former silicate be replaced, partially or fully, by other glass formers such as oxides of boron, phosphorous, tellurium or antimony, but also the oxygen anions can be substituted by fluorine or nitrogen. Chalcogens, the heavier ions in the group of oxygen in the periodic table (S, Se, Te), on their own or when paired with arsenic or germanium, can function as glass formers. Sulfate, nitrate, tungstate and acetate glasses lack the conventional anion and cation classification, as do metallic or organic glasses. The latter can occur naturally—amber predates anthropogenic glass manufacture by more than 200 million years.In this chapter, we are going to provide an overview of the different glass families, how the structure and properties of these different glass types differ from silicate glasses but also what similarities are dictated by the glassy state. Applications and technological aspects are discussed briefly for each glass family.

Interfacial nanostructure and friction of a polymeric ionic liquid-ionic liquid mixture as a function of potential at Au(1 1 1) electrode interface

HypothesisThe polymeric cations of polymeric ionic liquids (PILs) can adsorb from the bulk of a conventional ionic liquid (IL) to the Au(111) electrode interface and form a boundary layer. The interfacial properties of the PIL boundary layer may be tuned by potential. ExperimentsAtomic force microscopy has been used to investigate the changes of surface morphology, normal and lateral forces of a 5 wt% PIL/IL mixture as a function of potential. FindingsPolymeric cations adsorb strongly to Au(111) and form a polymeric cation-enriched boundary layer at −1.0 V. This boundary layer binds less strongly to the surface at open circuit potential (OCP) and weakly at + 1.0 V. The polymeric cation chains are compressed at −1.0 V and OCP owing to electrical attractions with the electrode surface, but fully stretched at + 1.0 V due to electrical repulsions. The lateral forces of the 5 wt% PIL/IL mixture at −1.0 V and OCP are higher than at + 1.0 V as the polymeric cation-enriched boundary layer is rougher and has stronger interactions with the AFM probe; at + 1.0 V, the lateral force is low and comparable to pure conventional IL due to displacement of polymeric cations with conventional anions in the boundary layer.

Grand scale genome manipulation via chromosome swapping in Escherichia coli programmed by three one megabase chromosomes.

In bacterial synthetic biology, whole genome transplantation has been achieved only in mycoplasmas that contain a small genome and are competent for foreign genome uptake. In this study, we developed Escherichia coli strains programmed by three 1-megabase (Mb) chromosomes by splitting the 3-Mb chromosome of a genome-reduced strain. The first split-chromosome retains the original replication origin (oriC) and partitioning (par) system. The second one has an oriC and the par locus from the F plasmid, while the third one has the ori and par locus of the Vibrio tubiashii secondary chromosome. The tripartite-genome cells maintained the rod-shaped form and grew only twice as slowly as their parent, allowing their further genetic engineering. A proportion of these 1-Mb chromosomes were purified as covalently closed supercoiled molecules with a conventional alkaline lysis method and anion exchange columns. Furthermore, the second and third chromosomes could be individually electroporated into competent cells. In contrast, the first split-chromosome was not able to coexist with another chromosome carrying the same origin region. However, it was exchangeable via conjugation between tripartite-genome strains by using different selection markers. We believe that this E. coli-based technology has the potential to greatly accelerate synthetic biology and synthetic genomics.

Stewart (physicochemical) approach versus conventional anion gap approach for resolution of metabolic acidosis in diabetic ketoacidosis

Diabetic ketoacidosis (DKA) frequently requires emergency admission. The anion gap approach is conventionally used for the diagnosis and documenting the resolution of acidosis during treatment. However, it fails to detect hyperchloremic acidosis during the resolution and may result in the prolongation of treatment. To determine the role of the Stewart approach of acid-base disorder during DKA management for the prediction of an earlier resolution. A prospective comparative study was conducted between January 2017 and December 2017 at a single academic hospital in north India. Patients aged above 12 years with a diagnosis of DKA were randomly divided into two groups—the conventional group and the Stewart group, according to the approach used for DKA resolution. The primary outcome was the time duration required for resolution. The secondary outcomes were the therapeutic requirement of intravenous fluid, insulin, and potassium, Acute Physiology and Chronic Health Evaluation II (APACHE II) score at the time of resolution, and hospital stay. Forty-four DKA patients were equally distributed in the two groups with comparable baseline parameters. The Stewart group had early resolution of DKA (mean, 32.4±17.5 h versus 41.7±19.6 h; p value <0.001) at similar APACHE II scores. The duration of hospital stay was reduced but was not statistically significant (mean, 5.6±3.2 days versus 7.0±3.8 days; p value 0.16). The therapeutic requirement of fluid, insulin, and potassium was similar in groups. The Stewart approach may be a better alternative to the conventional anion gap approach for guiding the resolution of DKA.