From Bulk to Interface: Solvent Exchange Dynamics and Their Role in Ion Transport and the Interfacial Model of Rechargeable Magnesium Batteries

Multivalent battery chemistries have been explored in response to the increasing demand for high-energy rechargeable batteries utilizing sustainable resources. Solvation structures of working cations have been recognized as a key component in the design of electrolytes; however, most structure-property correlations of metal ions in organic electrolytes usually build upon favorable static solvation structures, often overlooking solvent exchange dynamics. We here report the ion solvation structures and solvent exchange rates of magnesium electrolytes in various solvents by using multimodal nuclear magnetic resonance (NMR) analysis and molecular dynamics/density functional theory (MD/DFT) calculations. These magnesium solvation structures and solvent exchange dynamics are correlated to the combined effects of several physicochemical properties of the solvents. Moreover, Mg2+ transport and interfacial charge transfer efficiency are found to be closely correlated to the solvent exchange rate in the binary electrolytes where the solvent exchange is tunable by the fraction of diluent solvents. Our primary findings are (1) most battery-related solvents undergo ultraslow solvent exchange coordinating to Mg2+ (with time scales ranging from 0.5 μs to 5 ms), (2) the cation transport mechanism is a mixture of vehicular and structural diffusion even at the ultraslow exchange limit (with faster solvent exchange leading to faster cation transport), and (3) an interfacial model wherein organic-rich regions facilitate desolvation and inorganic regions promote Mg2+ transport is consistent with our NMR, electrochemistry, and cryogenic X-ray photoelectron spectroscopy (cryo-XPS) results. This observed ultraslow solvent exchange and its importance for ion transport and interfacial properties necessitate the judicious selection of solvents and informed design of electrolyte blends for multivalent electrolytes.

Understanding the Surprising Ionic Conductivity Maximum in Zn(TFSI)2 Water/Acetonitrile Mixture Electrolytes

Aqueous electrolytes composed of 0.1 M zinc bis(trifluoromethylsulfonyl)imide (Zn(TFSI)2) and acetonitrile (ACN) were studied using combined experimental and simulation techniques. The electrolyte was found to be electrochemically stable when the ACN V% is higher than 74.4. In addition, it was found that the ionic conductivity of the mixed solvent electrolytes changes as a function of ACN composition, and a maximum was observed at 91.7 V% of ACN although the salt concentration is the same. This behavior was qualitatively reproduced by molecular dynamics (MD) simulations. Detailed analyses based on experiments and MD simulations show that at high ACN composition the water network existing in the high water composition solutions breaks. As a result, the screening effect of the solvent weakens and the correlation among ions increases, which causes a decrease in ionic conductivity at high ACN V%. This study provides a fundamental understanding of this complex mixed solvent electrolyte system.

Enhancing CO2 Transport Across a PEEK-Ionene Membrane and Water-Lean Solvent Interface

Efficient direct air capture (DAC) of CO₂ will require strategies to deal with the relatively low concentration in the atmosphere. One such strategy is to employ the combination of a CO₂ -selective membrane coupled with a CO₂ capture solvent acting as a draw solution. Here, the interactions between a leading water-lean carbon-capture solvent, a polyether ether ketone (PEEK)-ionene membrane, CO₂ , and combinations were probed using advanced NMR techniques coupled with advanced simulations. We identify the speciation and dynamics of the solvent, membrane, and CO₂ , presenting spectroscopic evidence of CO₂ diffusion through benzylic regions within the PEEK-ionene membrane, not spaces in the ionic lattice as expected. Our results demonstrate that water-lean capture solvents provide a thermodynamic and kinetic funnel to draw CO₂ from the air through the membrane and into the bulk solvent, thus enhancing the performance of the membrane. The reaction between the carbon-capture solvent and CO₂ produces carbamic acid, disrupting interactions between the imidazolium (Im⁺ ) cations and the bistriflimide anions within the PEEK-ionene membrane, thereby creating structural changes through which CO₂ can diffuse more readily. Consequently, this restructuring results in CO₂ diffusion at the interface that is faster than CO₂ diffusion in the bulk carbon-capture solvent.

Interfacial Engineering with a Nanoparticle-Decorated Porous Carbon Structure on β″-Alumina Solid-State Electrolytes for Molten Sodium Batteries

We present a novel anode interface modification on the β″-alumina solid-state electrolyte that improves the wetting behavior of molten sodium in battery applications. Heat treating a simple slurry, composed only of water, acetone, carbon black, and lead acetate, formed a porous carbon network decorated with PbO_x (0 ≤ x ≤ 2) nanoparticles between 10 and 50 nm. Extensive performance analysis, through impedance spectroscopy and symmetric cycling, shows a stable, low-resistance interface for close to 6000 cycles. Furthermore, an intermediate temperature Na-S cell with a modified β″-alumina solid-state electrolyte could achieve an average stable cycling capacity as high as 509 mA h/g. This modification drastically decreases the amount of Pb content to approximately 3% in the anode interface (6 wt % or 0.4 mol %) and could further eliminate the need for toxic Pb altogether by replacing it with environmentally benign Sn. Overall, in situ reduction of oxide nanoparticles created a high-performance anode interface, further enabling large-scale applications of liquid metal anodes with solid-state electrolytes.

Understanding the Solvation-Dependent Properties of Cyclic Ether Multivalent Electrolytes Using High-Field NMR and Quantum Chemistry

Efforts to expand the technological capability of batteries have generated increased interest in divalent cationic systems. Electrolytes used for these electrochemical applications often incorporate cyclic ethers as electrolyte solvents; however, the detailed solvation environments within such systems are not well-understood. To foster insights into the solvation structures of such electrolytes, Ca(TFSI)2 and Zn(TFSI)2 dissolved in tetrahydrofuran (THF) and 2-methyl-tetrahydrofuran were investigated through multi-nuclear magnetic resonance spectroscopy (17O, 43Ca, and 67Zn NMR) combined with quantum chemistry modeling of NMR chemical shifts. NMR provides spectroscopic fingerprints that readily couple with quantum chemistry to identify a set of most probable solvation structures based on the best agreement between the theoretically predicted and experimentally measured values of chemical shifts. The multi-nuclear approach significantly enhances confidence that the correct solvation structures are identified due to the required simultaneous agreement between theory and experiment for multiple nuclear spins. Furthermore, quantum chemistry modeling provides a comparison of the solvation cluster formation energetics, allowing further refinement of the preferred solvation structures. It is shown that a range of solvation structures coexist in most of these electrolytes, with significant molecular motion and dynamic exchange among the structures. This level of solvation diversity correlates with the solubility of the electrolyte, with Zn(TFSI)2/THF exhibiting the lowest degree of each. Comparisons of analogous Ca2+ and Zn2+ solvation structures reveal a significant cation size effect that is manifested in significantly reduced cation-solvent bond lengths and thus stronger solvent bonding for Zn2+ relative to Ca2+. The strength of this bonding is further reduced by methylation of the cyclic ether ring. Solvation shells containing anions are energetically preferred in all the studied electrolytes, leading to significant quantities of contact ion pairs and consequently neutrally charged clusters. It is likely that the transport and interfacial de-solvation/re-solvation properties of these electrolytes are directed by these anion interactions. These insights into the detailed solvation structures, cation size, and solvent effects, including the molecular dynamics, are fundamentally important for the rational design of electrolytes in multivalent battery electrolyte systems.

Microsized Pore Structure Determination in EPDM Rubbers Using High-Pressure 129Xe NMR Techniques

Microsized pore parameters, such as pore size and distance between pores in a series of model EPDM rubbers, were determined in situ under the pressure of 500 psi using ¹²⁹Xe nuclear magnetic resonance (NMR) techniques: spin-lattice (T₁) and spin-spin (T₂) relaxation measurements, pulsed-field gradient (PFG) NMR, and two-dimensional exchange spectroscopy (2D EXSY). The T₁/T₂ (≫1) ratio for the xenon confined in the pores is larger than that for nonconfined free xenon. This suggests that almost the entire pore surface interacts with xenon atoms like a closed pore. While these pores still connect each other through very narrow diffusion/exchange channels, it is possible to observe the echo decay in PFG-NMR and cross-peaks in 2D EXSY. The results show that both diffusion (D_pore ≈ 2.1 × 10^-10 m²/s) and exchange (exchange rate, τ_exch = a few tens of milliseconds) of xenon between a pore within the material and outer surface are prolonged. The exchange distances (l), which correspond to the xenon gas penetration depth, were estimated to be 70-100 μm based on the measured diffusion coefficients and exchange rate (1/τ_exch). NMR diffraction analysis reveals that pore size (a) and pore distance (b) are on the order of magnitude of micrometers and tens of micrometers, while the diffusion coefficients of xenon gas in the diffusion channels (D_eff) are about 10^-8 m²/s. Overall, this study suggests that the pores with a few micrometers connected through very narrow flowing channels with the length of several tens of micrometers are developed 70 to 100 μm below the rubber surface. Furthermore, the overall steady-state diffusion of xenon is slower, approximately 2 orders of magnitudes, than the diffusion in the channel between the pores. The pore and exchange distances correlated with the composition of rubbers showed that the properties of EPDM rubber as a high-pressure gas barrier could be improved by reducing the size of cracks and the depth of gas penetration by the addition of both carbon black and silica fillers.

Body mass index at diagnosis of a childhood brain tumor; a reflection of hypothalamic-pituitary dysfunction or lifestyle?

PURPOSE

Childhood brain tumor survivors (CBTS) are at risk of becoming overweight, which has been shown to be associated with hypothalamic-pituitary (HP) dysfunction during follow-up. Body mass index (BMI) at diagnosis is related to BMI at follow-up. It is uncertain, however, whether aberrant BMI at brain tumor diagnosis reflects early hypothalamic dysfunction or rather reflects genetic and sociodemographic characteristics. We aimed to examine whether BMI at childhood brain tumor diagnosis is associated with HP dysfunction at diagnosis or its development during follow-up.

METHODS

The association of BMI at diagnosis of a childhood brain tumor to HP dysfunction at diagnosis or during follow-up was examined in a Dutch cohort of 685 CBTS, excluding children with craniopharyngioma or a pituitary tumor. Individual patient data were retrospectively extracted from patient charts.

RESULTS

Of 685 CTBS, 4.7% were underweight, 14.2% were overweight, and 3.8% were obese at diagnosis. Being overweight or obese at diagnosis was not associated with anterior pituitary deficiency or diabetes insipidus at diagnosis or during follow-up. In children with suprasellar tumors, being obese at diagnosis was associated with central precocious puberty.

CONCLUSION

Overweight or obesity at diagnosis of a childhood brain tumor seems not to be associated with pituitary deficiencies. These results suggest that genetics and lifestyle may be more important etiologic factors for higher BMI at diagnosis in these children than hypothalamic dysfunction. To improve the long-term outcome of CBTS with regards to overweight and obesity, more attention should be given to lifestyle already at the time of brain tumor treatment.

An automated framework for high-throughput predictions of NMR chemical shifts within liquid solutions

Identifying stable speciation in multi-component liquid solutions is fundamentally important to areas from electrochemistry to organic chemistry and biomolecular systems. Here we introduce a fully automated, high-throughput computational framework for the accurate prediction of stable species in liquid solutions by computing the nuclear magnetic resonance (NMR) chemical shifts. The framework automatically extracts and categorizes hundreds of thousands of atomic clusters from classical molecular dynamics simulations, identifies the most stable species in solution and calculates their NMR chemical shifts via density functional theory calculations. Additionally, the framework creates a database of computed chemical shifts for liquid solutions across a wide chemical and parameter space. We compare our computational results to experimental measurements for magnesium bis(trifluoromethanesulfonyl)imide Mg(TFSI)2 salt in dimethoxyethane solvent. Our analysis of the Mg2+ solvation structural evolutions reveals key factors that influence the accuracy of NMR chemical shift predictions in liquid solutions. Furthermore, we show how the framework reduces the performance of over 300 13C and 600 1H density functional theory chemical shift predictions to a single submission procedure.

Concentration-dependent ion correlations impact the electrochemical behavior of calcium battery electrolytes

Ion interactions strongly determine the solvation environments of multivalent electrolytes even at concentrations below that required for practical battery-based energy storage. This statement is particularly true of electrolytes utilizing ethereal solvents due to their low dielectric constants. These solvents are among the most commonly used for multivalent batteries based on reactive metals (Mg, Ca) due to their reductive stability. Recent developments in multivalent electrolyte design have produced a variety of new salts for Mg²⁺ and Ca²⁺ that test the limits of weak coordination strength and oxidative stability. Such electrolytes have great potential for enabling full-cell cycling of batteries based on these working ions. However, the ion interactions in these electrolytes exhibit significant and non-intuitive concentration relationships. In this work, we investigate a promising exemplar, calcium tetrakis(hexafluoroisopropoxy)borate (Ca(BHFIP)₂), in the ethereal solvents 1,2-dimethoxyethane (DME) and tetrahydrofuran (THF) across a concentration range of several orders of magnitude. Surprisingly, we find that effective salt dissociation is lower at relatively dilute concentrations (e.g. 0.01 M) than at higher concentrations (e.g. 0.2 M). Combined experimental and computational dielectric and X-ray spectroscopic analyses of the changes occurring in the Ca²⁺ solvation environment across these concentration regimes reveals a progressive transition from well-defined solvent-separated ion pairs to de-correlated free ions. This transition in ion correlation results in improvements in both conductivity and calcium cycling stability with increased salt concentration. Comparison with previous findings involving more strongly associating salts highlights the generality of this phenomenon, leading to important insight into controlling ion interactions in ether-based multivalent battery electrolytes.

Role of a Multivalent Ion-Solvent Interaction on Restricted Mg2+ Diffusion in Dimethoxyethane Electrolytes

The diffusion behavior of Mg²⁺ in electrolytes is not as readily accessible as that from Li⁺ or Na⁺ utilizing PFG NMR, due to the low sensitivity, poor resolution, and rapid relaxation encountered when attempting ²⁵Mg NMR. In MgTFSI₂/DME solutions, "bound" DME (coordinating to Mg²⁺) and "free" DME (bulk) are distinguishable from ¹H NMR. With the exchange rates between them obtained from 2D ¹H EXSY NMR, we can extract the self-diffusivities of free DME and bound DME (which are equal to that of Mg²⁺) before the exchange occurs using PFG diffusion NMR measurements coupled with analytical formulas describing diffusion under two-site exchange. The high activation enthalpy for exhange (65-70 kJ/mol) can be explained by the structural change of bound DME as evidenced by its reduced C-H bond length. Comparison of the diffusion behaviors of Mg²⁺, TFSI^-, DME, and Li⁺ reveals a relative restriction to Mg²⁺ diffusion that is caused by the long-range interaction between Mg²⁺ and solvent molecules, especially those with suppressed motions at high concentrations and low temperatures.

Prevalence and risk factors of hypothalamic-pituitary dysfunction in infant and toddler childhood brain tumor survivors

OBJECTIVE

Childhood brain tumor survivors (CBTS) are at risk to develop hypothalamic-pituitary (HP) dysfunction (HPD). The risk for HPD may vary between different age groups due to maturation of the brain and differences in oncologic treatment protocols. Specific studies on HPD in infant brain tumor survivors (infant-BTS, 0-1 years at diagnosis) or toddler brain tumor survivors (toddler-BTS, ≥1-3 years) have not been performed.

PATIENTS AND METHODS

A retrospective nationwide cohort study in CBTS was performed. Prevalence and risk factors for HPD were compared between infant-, toddler-, and older-BTS. Subgroup analysis was performed for all non-irradiated CBTS (n = 460).

RESULTS

In total, 718 CBTS were included, with a median follow-up time of 7.9 years. Overall, despite the less frequent use of radiotherapy (RT) in infants, no differences in the prevalence of HPD were found between the three groups. RT (OR: 16.44; 95% CI: 8.93-30.27), suprasellar tumor location (OR: 44.76; 95% CI: 19.00-105.49), and younger age (OR: 1.11; 95% CI: 1.05-1.18) were associated with HP dysfunction. Infant-BTS and toddler-BTS showed more weight gain (P < 0.0001) and smaller height SDS (P = 0.001) during follow-up. In non-irradiated CBTS, infant-BTS and toddler-BTS were significantly more frequently diagnosed with TSH-, ACTH-, and ADH deficiency, compared to older-BTS.

CONCLUSION

Infant and toddler brain tumor survivors seem to be more vulnerable to develop HP dysfunction than older children. These results emphasize the importance of special infant and toddler brain tumor treatment protocols and the need for endocrine surveillance in children treated for a brain tumor at a young age.

Concentration-Dependent Solvation Structure and Dynamics of Aqueous Sulfuric Acid Using Multinuclear NMR and DFT

Sulfuric acid is a ubiquitous compound for industrial processes, and aqueous sulfate solutions also play a critical role as electrolytes for many prominent battery chemistries. While the thermodynamic literature on it is quite well-developed, comprehensive studies of the solvation structure, particularly molecular-scale dynamical and transport properties, are less available. This study applies a multinuclear nuclear magnetic resonance (NMR) approach to the elucidation of the solvation structure and dynamics over wide temperature (-10 to 50 °C) and concentration (0-18 M) ranges, combining the ¹⁷O shift, line width, and T₁ relaxation measurements, ³³S shift and line width measurements, and ¹H pulsed-field gradient NMR measurements of proton self-diffusivity. In conjunction, these results indicate a crossover between two regimes of solvation structure and dynamics, occurring above the concentration associated with the deep eutectic point (∼4.5 M), with the high-concentration regime dominated by a strong water-sulfate correlation. This description was borne out in detail by the activation energy trends with increasing concentration derived from the relaxation of both the H₂O/H₃O⁺ and H₂SO₄/HSO₄^-/SO₄^{2- 17}O resonances and the ¹H self-diffusivity. However, the ¹⁷O chemical shift difference between the H₂O/H₃O⁺ and H₂SO₄/HSO₄^-/SO₄^2- resonances across the entire temperature range is nevertheless strikingly linear. A computational approach coupling molecular dynamics simulations and density functional theory NMR shift calculations to reproduce this trend is presented, which will be the subject of further development. This combination of multinuclear, dynamical NMR, and computational methods, and the results furnished by this study, will provide a platform for future studies on battery electrolytes where aqueous sulfate chemistry plays a central role in the solution structure.

Advanced Low-Flammable Electrolytes for Stable Operation of High-Voltage Lithium-Ion Batteries

Despite being an effective flame retardant, trimethyl phosphate (TMP_a ) is generally considered as an unqualified solvent for fabricating electrolytes used in graphite (Gr)-based lithium-ion batteries as it readily leads to Gr exfoliation and cell failure. In this work, by adopting the unique solvation structure of localized high-concentration electrolyte (LHCE) to TMP_a and tuning the composition of the solvation sheaths via electrolyte additives, excellent electrochemical performance can be achieved with TMP_a -based electrolytes in Gr∥LiNi_0.8 Mn_0.1 Co_0.1 O₂ cells. After 500 charge/discharge cycles within the voltage range of 2.5-4.4 V, the batteries containing the TMP_a -based LHCE with a proper additive can achieve a capacity retention of 85.4 %, being significantly higher than cells using a LiPF₆ -organocarbonates baseline electrolyte (75.2 %). Meanwhile, due to the flame retarding effect of TMP_a , TMP_a -based LHCEs exhibit significantly reduced flammability compared with the conventional LiPF₆ -organocarbonates electrolyte.

Quantifying Species Populations in Multivalent Borohydride Electrolytes

Multivalent batteries represent an important beyond Li-ion energy storage concept. The prospect of calcium batteries, in particular, has emerged recently due to novel electrolyte demonstrations, especially that of a ground-breaking combination of the borohydride salt Ca(BH₄)₂ dissolved in tetrahydrofuran. Recent analysis of magnesium and calcium versions of this electrolyte led to the identification of divergent speciation pathways for Mg²⁺ and Ca²⁺ despite identical anions and solvents, owing to differences in cation size and attendant flexibility of coordination. To test these proposed speciation equilibria and develop a more quantitative understanding thereof, we have applied pulsed-field-gradient nuclear magnetic resonance and dielectric relaxation spectroscopy to study these electrolytes. Concentration-dependent variation in anion diffusivities and solution dipole relaxations, interpreted with the aid of molecular dynamics simulations, confirms these divergent Mg²⁺ and Ca²⁺ speciation pathways. These results provide a more quantitative description of the electroactive species populations. We find that these species are present in relatively small quantities, even in the highly active Ca(BH₄)₂/tetrahydrofuran electrolyte. This finding helps interpret previous characterizations of metal deposition efficiency and morphology control and thus provides important fundamental insight into the dynamic properties of multivalent electrolytes for next-generation batteries.

Vacancy-Enabled O3 Phase Stabilization for Manganese-Rich Layered Sodium Cathodes

Manganese-rich layered oxide materials hold great potential as low-cost and high-capacity cathodes for Na-ion batteries. However, they usually form a P2 phase and suffer from fast capacity fade. In this work, an O3 phase sodium cathode has been developed out of a Li and Mn-rich layered material by leveraging the creation of transition metal (TM) and oxygen vacancies and the electrochemical exchange of Na and Li. The Mn-rich layered cathode material remains primarily O3 phase during sodiation/desodiation and can have a full sodiation capacity of ca. 220 mAh g^-1 . It delivers ca. 160 mAh g^-1 specific capacity between 2-3.8 V with >86 % retention over 250 cycles. The TM and oxygen vacancies pre-formed in the sodiated material enables a reversible migration of TMs from the TM layer to the tetrahedral sites in the Na layer upon de-sodiation and sodiation. The migration creates metastable states, leading to increased kinetic barrier that prohibits a complete O3-P3 phase transition.

Enabling Ether-Based Electrolytes for Long Cycle Life of Lithium-Ion Batteries at High Charge Voltage

Lithium-ion batteries (LIBs) with high-nickel (Ni) content LiNi_xMn_yCo_zO₂ (x + y + z = 1) (NMC with Ni ≥ 0.6) cathodes operated at high charge voltages have been considered as one of the most promising candidates for addressing the challenge of increasing energy density demand. Conventional LiPF₆-organocarbonate electrolytes exhibit incompatibility with such cell chemistries under certain testing conditions because of the instability of electrode/electrolyte interphases. In response to this challenge, ether-based electrolytes with finely tuned structure and composition of solvation sheaths were developed and evaluated in graphite (Gr)∥NMC811 cell chemistry in 2.5-4.4 V, despite ethers being conventionally considered to be unfavorable electrolyte solvents for LIBs because of their anodic instability above 4.0 V and cointercalation into Gr electrodes. The functional ether-based electrolytes in this work enable both excellent cycle life and high rate capability of Gr∥NMC811 cells. Mechanistic studies reveal that the unique structure and composition of the solvation sheath of the functional ether electrolytes are the main reasons behind their excellent anodic stability and effective protection of the Gr electrode and, consequently, the extraordinary cell performances when operated at high charge cutoff voltages. This work also provides a feasible approach in developing highly stable functional electrolytes for high-energy density LIBs.

An Ultra-Microporous Metal-Organic Framework with Exceptional Xe Capacity

Molecular confinement plays a significant effect on trapped gas and solvent molecules. A fundamental understanding of gas adsorption within the porous confinement provides information necessary to design a material with improved selectivity. In this regard, metal-organic framework (MOF) adsorbents are ideal candidate materials to study confinement effects for weakly interacting gas molecules, such as noble gases. Among the noble gases, xenon (Xe) has practical applications in the medical, automotive and aerospace industries. In this Communication, we report an ultra-microporous nickel-isonicotinate MOF with exceptional Xe uptake and selectivity compared to all benchmark MOF and porous organic cage materials. The selectivity arises because of the near perfect fit of the atomic Xe inside the porous confinement. Notably, at low partial pressure, the Ni-MOF interacts very strongly with Xe compared to the closely related Krypton gas (Kr) and more polarizable CO₂ . Further ¹²⁹ Xe NMR suggests a broad isotropic chemical shift due to the reduced motion as a result of confinement.

Subtle changes in hydrogen bond orientation result in glassification of carbon capture solvents

Water-lean CO₂ capture solvents show promise for more efficient and cost-effective CO₂ capture, although their long-term behavior in operation has yet to be well studied. New observations of extended structure solvent behavior show that some solvent formulations transform into a glass-like phase upon aging at operating temperatures after contact with CO₂. The glassification of a solvent would be detrimental to a carbon-capture process due to plugging of infrastructure, introducing a critical need to decipher the underlying principles of this phenomenon to prevent it from happening. We present the first integrated theoretical and experimental study to characterize the nano-structure of metastable and glassy states of an archetypal single-component alkanolguanidine carbon-capture solvent and assess how minute changes in atomic-level interactions convert the solvent between metastable and glass-like states. Small-angle neutron scattering and neutron diffraction coupled with small- and wide-angle X-ray scattering analysis demonstrate that minute structural changes in solution precipitae reversible aggregation of zwitterionic alkylcarbonate clusters in solution. Our findings indicate that our test system, an alkanolguanidine, exhibits a first-order phase transition, similar to a glass transition, at approximately 40 °C-close to the operating absorption temperature for post-combustion CO₂ capture processes. We anticipate that these phenomena are not specific to this system, but are present in other classes of colvents as well. We discuss how molecular-level interactions can have vast implications for solvent-based carbon-capture technologies, concluding that fortunately in this case, glassification of water-lean solvents can be avoided as long as the solvent is run above its glass transition temperature.

Role of Solvent Rearrangement on Mg2+ Solvation Structures in Dimethoxyethane Solutions using Multimodal NMR Analysis

One of the main impediments faced for predicting emergent properties of a multivalent electrolyte (such as conductivity and electrochemical stability) is the lack of quantitative analysis of ion-ion and ion-solvent interactions, which manifest in solvation structures and dynamics. In particular, the role of ion-solvent interactions is still unclear in cases where the strong electric field from multivalent cations can influence intramolecular rotations and conformal structural evolution (i.e., solvent rearrangement process) of low permittivity organic solvent molecules on solvation structure. Using quantitative ¹H, ¹⁹F, and ¹⁷O NMR together with ¹⁹F nuclear spin relaxation and diffusion measurments, we find an unusual correlation between ion concentration and solvation structure of Mg(TFSI)₂ salt in dimethoxyethane (DME) solution. The dominant solvation structure evolves from contact ion pairs (i.e., [Mg(TFSI)(DME)_1-2]⁺) to fully solvated clusters (i.e., [Mg(DME)₃]²⁺) as salt concentration increases or as temperature decreases. This transition is coupled to a phase separation, which we study here between 0.06 and 0.36 M. Subsequent analysis is based on an explanation of the solvent rearrangement process and the competition between solvent molecules and TFSI anions for cation coordination.

Cotton Fiber-Based Sorbents for Treating Crude Oil Spills

Wood and plant fibers have been studied as natural sorbent materials for treating aquatic oil spills; however, the effectiveness of these materials is limited by their tendency to absorb water as well as oil. Chemical pretreatment of cotton fibers with fatty acids was examined as a means of enhancing the performance of cotton as a sorbent for crude oil. A raw cotton fiber was chemically modified with C18 fatty acid by simple leaving group chemistry. Free surface hydroxyl groups were modified with long alkyl chains to create fibers that displayed increased water contact angles, indicative of a significant decrease in surface energy. The increased affinity for oil and corresponding repulsion of water on the individual modified fibers translated to greater sorption of oil and rejection of water by loose assemblies of fibers (i.e., balls or yarn) when compared with unmodified cotton. X-ray diffraction (XRD) pattern, Fourier transform infrared (FT-IR), ¹³C cross-polarization/magic angle spinning solid-state nuclear magnetic resonance (CP/MAS SSNMR), and scanning electron microscopy (SEM) showed that cotton fibers were significantly exfoliated by the intercalation of C18 fatty acids about 2.4 times in its diameter. In the presence of seawater, the highly oleophilic C18 fatty acid-modified cotton fiber showed a maximum oil sorption capacity of 35.58 g per gram of fiber, about ∼49% greater than that of the corresponding raw cotton fiber.

Metal-Organic Framework-Based Microfluidic Impedance Sensor Platform for Ultrasensitive Detection of Perfluorooctanesulfonate

The growing global concerns to public health from human exposure to perfluorooctanesulfonate (PFOS) require rapid, sensitive, in situ detection where current, state-of-the-art techniques are yet to adequately meet sensitivity standards of the real world. This work presents, for the first time, a synergistic approach for the targeted affinity-based capture of PFOS using a porous sorbent probe that enhances detection sensitivity by embedding it on a microfluidic platform. This novel sorbent-containing platform functions as an electrochemical sensor to directly measure PFOS concentration through a proportional change in electrical current (increase in impedance). The extremely high surface area and pore volume of mesoporous metal-organic framework (MOF) Cr-MIL-101 is used as the probe for targeted PFOS capture based on the affinity of the chromium center toward both the fluorine tail groups as well as the sulfonate functionalities as demonstrated by spectroscopic (NMR and XPS) and microscopic (TEM) studies. Answering the need for an ultrasensitive PFOS detection technique, we are embedding the MOF capture probes inside a microfluidic channel, sandwiched between interdigitated microelectrodes (IDμE). The nanoporous geometry, along with interdigitated microelectrodes, increases the signal-to-noise ratio tremendously. Further, the ability of the capture probes to interact with the PFOS at the molecular level and effectively transduce that response electrochemically has allowed us achieve a significant increase in sensitivity. The PFOS detection limit of 0.5 ng/L is unprecedented for in situ analytical PFOS sensors and comparable to quantification limits achieved using state-of-the-art ex situ techniques.

Adsorption and Thermal Decomposition of Electrolytes on Nanometer Magnesium Oxide: An in Situ 13C MAS NMR Study

Mg batteries have been proposed as potential alternatives to lithium-ion batteries because of their lower cost, higher safety, and enhanced charge density. However, the Mg metal readily oxidizes when exposed to an oxidizer to form a thin MgO passivation surface layer that blocks the transport of Mg²⁺ across the solid electrode-electrolyte interface (SEI). In this work, the adsorption and thermal decomposition of diglyme (G2) and electrolytes containing Mg(TFSI)₂ in G2 on 10 nm-sized MgO particles are evaluated by a combination of in situ ¹³C single-pulse, surface-sensitive ¹H-¹³C cross-polarization (CP) magic-angle spinning (MAS) nuclear magnetic resonance, and quantum chemistry calculations. At 180 °C, neat G2 decomposes on MgO to form surface-adsorbed -OCH₃ groups that are captured as a distinctive peak located at about 50 ppm in the CP/MAS spectrum. At low Mg(TFSI)₂ salt concentration, the main solvation structure in this electrolyte is solvent-separated ion pairs without extensive Mg-TFSI contact ion pairs. G2, likely including a small amount of G2-solvated Mg²⁺, adsorbs onto the MgO surface. At high Mg(TFSI)₂ salt concentrations, contact ion pairs between Mg and TFSI are formed extensively in the solution with the first solvation shell containing one pair of Mg-TFSI and two G2 molecules and the second solvation shell containing up to six G2 molecules, namely, MgTFSI(G2)₂(G2)₆⁺. In the presence of MgO, MgTFSI(G2)₂(G2)₆⁺ adsorbs onto the MgO surface. At 180 °C, the MgO surface stimulates a desolvation process converting MgTFSI(G2)₂(G2)₆⁺ to MgTFSI(G2)₂⁺ and releasing G2 molecules from the second solvation shell of the MgTFSI(G2)₂(G2)₆⁺ cluster into the solution. MgTFSI(G2)₂⁺ and MgTFSI(G2)₂(G2)₆⁺ tightly adsorb onto the MgO surface and are observed by ¹H-¹³C CP/MAS experiments. The results contained herein show that electrolyte composition has a directing role in the species present on the electrode surface, which has implications on the structures and constituents of the solid-electrolyte interface on working electrodes and can be used to better understand its formation and the failure modes of batteries.

Joint Charge Storage for High-Rate Aqueous Zinc-Manganese Dioxide Batteries

Aqueous rechargeable zinc-manganese dioxide batteries show great promise for large-scale energy storage due to their use of environmentally friendly, abundant, and rechargeable Zn metal anodes and MnO₂ cathodes. In the literature various intercalation and conversion reaction mechanisms in MnO₂ have been reported, but it is not clear how these mechanisms can be simultaneously manipulated to improve the charge storage and transport properties. A systematical study to understand the charge storage mechanisms in a layered δ-MnO₂ cathode is reported. An electrolyte-dependent reaction mechanism in δ-MnO₂ is identified. Nondiffusion controlled Zn²⁺ intercalation in bulky δ-MnO₂ and control of H⁺ conversion reaction pathways over a wide C-rate charge-discharge range facilitate high rate performance of the δ-MnO₂ cathode without sacrificing the energy density in optimal electrolytes. The Zn-δ-MnO₂ system delivers a discharge capacity of 136.9 mAh g^-1 at 20 C and capacity retention of 93% over 4000 cycles with this joint charge storage mechanism. This study opens a new gateway for the design of high-rate electrode materials by manipulating the effective redox reactions in electrode materials for rechargeable batteries.

Enhanced Capacities of Mixed Fatty Acid-Modified Sawdust Aggregators for Remediation of Crude Oil Spill

Mixed fatty acid-modified aggregators have been developed as potential crude oil sorbents. Cheap pine wood flour was first modified with oleic acid (OA) and further modified with a second fatty acid by a leaving group chemistry, where a surface hydroxyl group is first replaced by p-toluenesulfonyl group and a fatty acid forms a covalent bond on sawdust surface through esterification at the elevated temperature (55 °C). Two OA-modified base materials, pine/OA-106 and pine/OA-124, with different OA-coverages were first prepared and the second fatty acids with C3, C6, C8, C10, C12, C14, or C16 alkyl chains were applied to cover the remaining surface hydroxyl groups. The crude oil sorption capacities of the mixed fatty acid-modified aggregators were studied and compared with those of the base materials. The results showed that mixed fatty acid-modified aggregators increased up to 45.6% more crude oil sorption than those of OA-modified base materials. A correlation between surface property and sorption capacity was studied by moisture sorption, Fourier transform infrared spectroscopy, X-ray diffraction, 13C cross polarization and magic angle spinning nuclear magnetic resonance, thermal gravimetric analysis, and scanning electron microscopy. To our knowledge, no report has been published for mixed fatty acid-modified herders or aggregators in the environmental remediation.

Electrode Edge Effects and the Failure Mechanism of Lithium-Metal Batteries

The very high specific capacity of Li metal makes it an ideal anode for high-energy batteries. However, Li dendrite growth and the formation of isolated (or "dead") Li during repeated Li plating/stripping processes leads to a low coulombic efficiency (CE). In this work, we discovered, for the first time, that electrode edge effects play an important role in the failure of Li-metal batteries. The dead Li formed on the edge of Cu substrate was systematically investigated through SEM, energy-dispersive X-ray (EDX) spectroscopy, and 2D X-ray photoelectron spectroscopy (XPS). To minimize the Li loss at the edge of the Cu exposed to pressure-free space, a modified Li∥Cu cell configuration with a Cu electrode smaller than Li metal is preferred. It was clearly demonstrated that using an electrode configuration with a minimal open space or pressure-free space across electrodes can reduce accumulation of dead Li during cycling and increase Li CE. This phenomenon was also verified in Li-metal batteries (Li∥LiNi_1/3 Mn_1/3 Co_1/3 O₂ ) and should be considered in the design of practical Li-metal batteries.

Controlled Synthesis of Sulfur-Rich Polymeric Selenium Sulfides as Promising Electrode Materials for Long-Life, High-Rate Lithium Metal Batteries

High-energy lithium/sulfur (Li/S) batteries still suffer from unsatisfactory cycle life and poor rate capability caused by the polysulfides shuttle and insulating nature of S cathodes. Here, we report our findings in the controlled synthesis of selenium (Se)-containing S-rich co-polymers of various compositions as novel cathode materials through a facile inverse vulcanization of S with selenium disulfide (SeS₂) and 1,3-diisopropenylbenzene (DIB) as co-monomers. Nuclear magnetic resonance and X-ray photoelectron spectroscopy results show that divinyl functional groups of DIB were chemically cross-linked with S/SeS₂ chain radicals through a ring-opening polymerization. The newly formed bonds of C-S, C-Se, and S-Se in novel S-SeS₂-DIB co-polymers effectively alleviate the shuttle effects of polysulfides/polyselenides. Furthermore, various electrochemical techniques confirm the positive roles of Se-containing co-polymers in enhancing the electrode reaction kinetics and the formation of stable solid electrolyte interphase layer with low charge-transfer resistance, leading to improved high-rate performances. The as-synthesized co-polymer was then infiltrated into well-interconnected, porous nanocarbon networks (Ketjenblack EC600JD, KB600) to provide effective paths for the fast electron transport. Due to the synergistic combination of chemical and physical confinement of the reaction intermediates during cycling, good reversibility for 500 cycles with a low decay rate of 0.0549% per cycle was achieved at 1000 mA g^-1. These encouraging results suggest that the combination of chemical incorporation of SeS₂ into S-rich co-polymer and the physical confinement of carbon networks is a promising strategy for advancing Li/S batteries and their viability for practical applications.

Management and consequences of postoperative fluctuations in plasma sodium concentration after pediatric brain tumor surgery in the sellar region: a national cohort analysis

PURPOSE

Severe fluctuations in plasma sodium concentration and plasma osmolarity, including central diabetes insipidus (CDI), may have significant influence on postoperative morbidity and mortality after pediatric brain tumor surgery.The aim of this study was to describe the frequency, severity and neurological consequences of these fluctuations in pediatric brain tumor survivors.

METHODS

A retrospective, multi-institutional chart review was conducted among all children who underwent brain tumor surgery in the sellar or suprasellar region in seven university hospitals in the Netherlands between January 2004 and December 2013.

RESULTS

Postoperative CDI was observed in 67.5% of 120 included children. Fluctuations of plasma sodium concentration ≥ 10 mmol/L/24 h during the first ten postoperative days were seen in 75.3% of patients with CDI, with a maximum delta of 46 mmol/L/24 h. When compared to patients without CDI, altered mental status occurred more frequently in patients with postoperative CDI (5.1 vs. 23.5% respectively, p = 0.009). Low plasma sodium concentration was related to altered mental status and the occurrence of seizures. Frequency and severity of fluctuations in plasma sodium concentration during the first ten postoperative days were significantly higher in patients with permanent CDI at last follow-up than in patients with transient CDI or without CDI (p = 0.007).

CONCLUSION

Postoperative CDI is a common complication after pediatric brain tumor surgery in the sellar or suprasellar region. Extreme plasma sodium concentrations and large intra-day fluctuations still occur and seem to influence the postoperative neurological course. These results illustrate the need for intensive monitoring in a highly experienced center.

High-Voltage Lithium-Metal Batteries Enabled by Localized High-Concentration Electrolytes

Rechargeable lithium-metal batteries (LMBs) are regarded as the "holy grail" of energy-storage systems, but the electrolytes that are highly stable with both a lithium-metal anode and high-voltage cathodes still remain a great challenge. Here a novel "localized high-concentration electrolyte" (HCE; 1.2 m lithium bis(fluorosulfonyl)imide in a mixture of dimethyl carbonate/bis(2,2,2-trifluoroethyl) ether (1:2 by mol)) is reported that enables dendrite-free cycling of lithium-metal anodes with high Coulombic efficiency (99.5%) and excellent capacity retention (>80% after 700 cycles) of Li||LiNi_1/3 Mn_1/3 Co_1/3 O₂ batteries. Unlike the HCEs reported before, the electrolyte reported in this work exhibits low concentration, low cost, low viscosity, improved conductivity, and good wettability that make LMBs closer to practical applications. The fundamental concept of "localized HCEs" developed in this work can also be applied to other battery systems, sensors, supercapacitors, and other electrochemical systems.

Use of steric encumbrance to develop conjugated nanoporous polymers for metal-free catalytic hydrogenation

The design and synthesis of metal-free heterogeneous catalysts for efficient hydrogenation remains a great challenge. Here we report a novel approach to create conjugated nanoporous polymers with efficient hydrogenation activities toward unsaturated ketones by leveraging the innate steric encumbrance. The steric bulk of the framework as well as the local sterics of the Lewis basic sites within the polymeric skeleton result in the generation of the putative catalyst. This approach opens up new possibilities for the development of innovative metal-free heterogeneous catalysts.

Improving Lithium-Sulfur Battery Performance under Lean Electrolyte through Nanoscale Confinement in Soft Swellable Gels

Li-S batteries have been extensively studied using rigid carbon as the host for sulfur encapsulation, but improving the properties with a reduced electrolyte amount remains a significant challenge. This is critical for achieving high energy density. Here, we developed a soft PEO₁₀LiTFSI polymer swellable gel as a nanoscale reservoir to trap the polysulfides under lean electrolyte conditions. The PEO₁₀LiTFSI gel immobilizes the electrolyte and confines polysulfides within the ion conducting phase. The Li-S cell with a much lower electrolyte to sulfur ratio (E/S) of 4 g_E/g_S (3.3 mL_E/g_S) could deliver a capacity of 1200 mA h/g, 4.6 mA h/cm², and good cycle life. The accumulation of polysulfide reduction products, such as Li₂S, on the cathode, is identified as the potential mechanism for capacity fading under lean electrolyte conditions.

Ammonium Additives to Dissolve Lithium Sulfide through Hydrogen Binding for High-Energy Lithium-Sulfur Batteries

In rechargeable Li-S batteries, the uncontrollable passivation of electrodes by highly insulating Li₂S limits sulfur utilization, increases polarization, and decreases cycling stability. Dissolving Li₂S in organic electrolyte is a facile solution to maintain the active reaction interface between electrolyte and sulfur cathode, and thus address the above issues. Herein, ammonium salts are demonstrated as effective additives to promote the dissolution of Li₂S to 1.25 M in DMSO solvent at room temperature. NMR measurements show that the strong hydrogen binding effect of N-H groups plays a critical role in dissolving Li₂S by forming complex ligands with S^2- anions coupled with the solvent's solvating surrounding. Ammonium additives in electrolyte can also significantly improve the oxidation kinetics of Li₂S, and therefore enable the direct use of Li₂S as cathode material in Li-S battery system in the future. This provides a new approach to manage the solubility of lithium sulfides through cation coordination with sulfide anion.

Rectal tube drainage reduces major anastomotic leakage after minimally invasive rectal cancer surgery

AIM

Anastomotic leakage is the most serious complication following low anterior resection for rectal cancer and is a major cause of postoperative morbidity and mortality. The object of the present study was to investigate whether rectal tube drainage can reduce anastomotic leakage after minimally invasive rectal cancer surgery.

METHOD

Three hundred and seventy-four patients who underwent laparoscopic or robotic LAR for tumours located ≤ 15 cm above the anal verge between 1 April 2012 and 31 October 2014 were assessed retrospectively. Of these, 107 with intermediate risk of anastomotic leakage received transanal rectal tube drainage. The rectal tube group was matched by propensity score analysis with patients not having rectal tube drainage, giving 204 patients in the study. Covariates for propensity score analysis included age, sex, body mass index, tumour height from the anal verge and preoperative chemoradiation.

RESULTS

Patient demographics, tumour location, preoperative chemoradiation and operative results were similar between the two groups. The overall leakage rate was 10.8% (22/204), with no significant difference between the rectal tube group (9.8%) and the nonrectal tube group (11.8%, P = 0.652). Of the patients with anastomotic leakage, major leakage requiring reoperation developed in 11.8% of those without and 3.9% of those with a rectal tube. On multivariate analysis, age over 65 years and nonuse of a rectal tube were found to be independent risk factors for major anastomotic leakage.

CONCLUSION

Rectal tube placement may be a safe and effective method of reducing the rate of major anastomotic leakage, alleviating the clinical course of leakage following minimally invasive rectal cancer surgery.

Facilitated Ion Transport in Smectic Ordered Ionic Liquid Crystals

A novel ionic mixture of an imidazolium-based room-temperature ionic liquid containing ethylene-oxide-functionalized phosphite anions is fabricated, which, when doped with lithium salt, self-assembles into a smectic-ordered ionic liquid crystal through Coulombic interactions between the ion species. Interestingly, the smectic order in the ionic-liquid-crystal ionogel facilitates ionic transport.

Long-term outcomes of locally or radically resected T1 colorectal cancer

AIM

Little is known about the long-term outcome of T1 colorectal cancer (CRC) following curative resection. The present study addressed the long-term outcome of locally or radically resected T1 CRCs.

METHOD

A total of 430 patients with T1 CRC who underwent local or radical resection were considered. Unfavourable histological factors were defined as positive resection margin, deep submucosal invasion, vascular invasion, Grade 3 and budding. The patients were classified as low-risk (unfavourable histological factor negative, n = 65) or high-risk (unfavourable histological factor positive, n = 365).

RESULTS

Over a median follow-up of 78.4 months, disease recurred in 16 (3.7%) patients in the high-risk group, and no recurrence in the low-risk group. Resection type and vascular invasion were significantly associated with recurrence. In the vascular invasion (+) high-risk group, both 5-year disease-free survival rate and 5-year overall survival rate were significantly associated with resection type (radical 94.6%, local 43.8%, P < 0.001, and radical 99.1%, local 66.7%, P < 0.001). In the vascular invasion (-) high-risk group, 5-year disease-free survival rate was also significantly associated with resection type (radical 98.9%, local 84.7%, P = 0.001). However, 5-year overall survival rate was not associated with resection type (radical 98.9%, local 95.2%, P = 0.816).

CONCLUSION

Local resection may be effective and oncologically safe in low-risk T1 CRC. Although additional surgery should be recommended for the locally resected high-risk T1 CRC cases, intensive surveillance without additional surgery and timely salvage operation may offer another treatment option, if vascular invasion is negative.

Toward the design of high voltage magnesium–lithium hybrid batteries using dual-salt electrolytes

We report a design of high voltage magnesium–lithium (Mg–Li) hybrid batteries through rational control of the electrolyte chemistry, electrode materials and cell architecture.

Highly active electrolytes for rechargeable Mg batteries based on a [Mg2(μ-Cl)2](2+) cation complex in dimethoxyethane

A novel [Mg2(μ-Cl)2](2+) cation complex, which is highly active for reversible Mg electrodeposition, was identified for the first time in this work. This complex was found to be present in electrolytes formulated in dimethoxyethane (DME) through dehalodimerization of non-nucleophilic MgCl2 by reacting with either Mg salts (such as Mg(TFSI)2, TFSI = bis(trifluoromethane)sulfonylimide) or Lewis acid salts (such as AlEtCl2 or AlCl3). The molecular structure of the cation complex was characterized by single crystal X-ray diffraction, Raman spectroscopy and NMR. The electrolyte synthesis process was studied and rational approaches for formulating highly active electrolytes were proposed. Through control of the anions, electrolytes with an efficiency close to 100%, a wide electrochemical window (up to 3.5 V) and a high ionic conductivity (>6 mS cm(-1)) were obtained. The understanding of electrolyte synthesis in DME developed in this work could bring significant opportunities for the rational formulation of electrolytes of the general formula [Mg2(μ-Cl)2][anion]x for practical Mg batteries.

Solvation structure and transport properties of alkali cations in dimethyl sulfoxide under exogenous static electric fields

A combination of molecular dynamics simulations and pulsed field gradient nuclear magnetic resonance spectroscopy is used to investigate the role of exogenous electric fields on the solvation structure and dynamics of alkali ions in dimethyl sulfoxide (DMSO) and as a function of temperature. Good agreement was obtained, for select alkali ions in the absence of an electric field, between calculated and experimentally determined diffusion coefficients normalized to that of pure DMSO. Our results indicate that temperatures of up to 400 K and external electric fields of up to 1 V nm(-1) have minimal effects on the solvation structure of the smaller alkali cations (Li(+) and Na(+)) due to their relatively strong ion-solvent interactions, whereas the solvation structures of the larger alkali cations (K(+), Rb(+), and Cs(+)) are significantly affected. In addition, although the DMSO exchange dynamics in the first solvation shell differ markedly for the two groups, the drift velocities and mobilities are not significantly affected by the nature of the alkali ion. Overall, although exogenous electric fields induce a drift displacement, their presence does not significantly affect the random diffusive displacement of the alkali ions in DMSO. System temperature is found to have generally a stronger influence on dynamical properties, such as the DMSO exchange dynamics and the ion mobilities, than the presence of electric fields.

First Report of Choanephora Rot Caused by Choanephora cucurbitarum on Hosta plantaginea in Korea

Hosta plantaginea (Lam.) Asch. is an herbaceous perennial plant with ornamental value. In August 2013, water-soaked spots and wet rot were found on flowers of H. plantaginea in a garden bedded out for landscaping in Hongcheon County, Korea. Symptoms initially appeared as water-soaked spots at the tips of flowers. Dark gray spots on flower petals often coalesced and led to rotting of flowers, with abundant sporulation. However, no symptoms were found on the leaves. Approximately 30% of the flowers were affected in the landscape bed. A fungal isolate was obtained by plating surface-disinfested diseased flower tissue on potato dextrose agar (PDA). Fungal colonies covering the plate (diam. 90 mm) in 48 h were white at first, with abundant aerial mycelia, but later turned pale yellow with abundant sporangiola. Sporangiophores bearing sporangiola were aseptate, hyaline, and usually arose from infected tissue. Sporangiola were ellipsoid to ovoid, indehiscent, brown to dark brown, pediculate, 7 to 12 μm wide and 9 to 20 μm high, and showed longitudinal striations at high magnification. Sporangia were few-spored to multispored, pale brown to brown, and 50 to 150 μm. Sporangiospores from sporangia were broadly ellipsoid, brown to pale brown, with hyaline polar appendages, 8 to 10 μm wide and 15 to 22 μm high. Zygospores were not observed. The morphological and cultural characteristics, especially based on shape and striation of sporangiola, were identical with those of Choanephora cucurbitarum (Berk. & Ravenel) Thaxt. (2,3). A representative specimen was deposited in the Korea University Herbarium (KUS-F27540). Genomic DNA was extracted using a DNeasy Plant Mini Kit (Qiagen Inc., Valencia, CA). The primers ITS1/ITS4 and NL1/LR3 were used to amplify the internal transcribed spacer (ITS) region of rDNA and the D1/D2 region of the large subunit (LSU), respectively (4). The PCR products were purified and directly sequenced. The resulting 594-bp ITS and 680-bp D1/D2 sequences were submitted to GenBank (Accession Nos. KM200034 and KM200035). A GenBank BLAST search of the fungal database showed that the sequences of ITS and D1/D2 regions matched those of C. cucurbitrarum (JN943006 and JN939195) with 100% similarity. A pathogenicity test was conducted by spraying three healthy potted plants (2 months old) with a sporangiola suspension (2 × 10⁴ conidia/ml). Another three potted plants of the same age were treated with sterile water and served as controls. The plants were kept in humid chambers for 2 days and placed in a greenhouse (28°C and 60 to 80% RH). After 4 to 5 days, water-soaked spots were evident on the flowers of inoculated plants. No symptoms were observed on control plants. A pathogenicity test was conducted twice with the same results, fulfilling Koch's postulates. C. cucurbitarum has a wide host range but has not been previously reported to cause disease on H. plantaginea (1). To our knowledge, this is the first report of C. cucurbitarum on H. plantaginea globally as well as in Korea. Choanephora rot of flowers is an issue under high-moisture conditions, so allowing for adequate airflow and a dry plant canopy should aid in disease suppression. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab. Online publication, ARS, USDA, retrieved July 11, 2014. (2) P. M. Kirk. Mycol. Pap. 152:1, 1984. (3) A. Saroj et al. Plant Dis. 96:293, 2012. (4) G. Walther et al. Persoonia 30:11, 2013.

First Report of Choanephora Blight Caused by Choanephora infundibulifera on Hibiscus rosa-sinensis in Korea

Hibiscus rosa-sinensis L., commonly known as Chinese hibiscus, is an evergreen flowering shrub belonging to the Malvaceae and is widely cultivated throughout Asia including Korea. In August 2013, blight was observed on Chinese hibiscus in a commercial flower nursery in Seoul, Korea. Initial symptoms began as reddish purple spots at the tip of flowers and expanded to encompass entire flowers. Infected lesions appeared water-soaked, reddish brown, and were followed by rapid rotting of infected tissues. Approximately 50% of the plants surveyed were affected. Monosporous sporangiola formed on infected tissue were transferred to potato dextrose agar (PDA). Fungal colonies were obtained that were at first white with abundant aerial mycelium, and then became yellowish with the appearance of sporangiola. Sporangiophores bearing sporangiola were erect to slightly curved, unbranched, and hyaline. Funnel-shaped secondary vesicles formed on the primary vesicles. Sporangiola were indehiscent, ovoid to subglobose, smooth, non-striated, brown to dark brown, 10 to 27.5 × 8.5 to 17 μm, and sometimes germinated in culture. The fungus was identified as Choanephora infundibulifera (Curr.) D.D. Cunn. based on the morphological and cultural characteristics (2). Voucher specimens were housed in the Korea University Herbarium (KUS). An isolate obtained from KUS-F27535 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC47643) and used for a pathogenicity test and molecular analyses. To confirm identity of the fungus, genomic DNA was extracted with DNeasy Plant Mini Kits (Qiagen Inc., Valencia, CA). The internal transcribed spacer (ITS) region of rDNA and the D1/D2 region of the large subunit (LSU) were amplified with the primers ITS1/ITS4 and NL1/LR3, respectively (3), and sequenced. The resulting 635-bp ITS and 680-bp D1/D2 sequences were deposited in GenBank (Accession Nos. KF486539 and KF486538). A GenBank BLAST search revealed that the ITS sequences showed 100% similarity with that of C. infundibulifera (JN943009) and D1/D2 sequences also showed 100% identity with that of C. infundibulifera (JN939193). A sporangiola suspension (2 × 10⁴ cells/ml) was sprayed over three pots of the shrub, kept in a humid chamber for 2 days, and placed in greenhouse (28°C and 80 to 100% RH). Another three potted plants of the same age were sprayed with sterile water and served as controls. After 4 days, typical blossom blight symptoms, identical to the ones observed in the nursery, developed on the inoculated flowers. No symptoms were observed on controls. C. infundibulifera was re-isolated from inoculated plants. Pathogenicity test was conducted twice with the same results, fulfilling Koch's postulates. Choanephora blight caused by C. infundibulifera on H. rosa-sinenesis has been reported in Japan, Myanmar, Nepal, Guinea, and the United States (1). In Korea, there was one record of this fungus on H. syriacus (1). To our knowledge, this is the first report of C. infundibulifera on H. rosa-sinensis in Korea. This pathogen could be a potential threat to the production of this ornamental shrub over a prolonged period of hot and humid weather. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved February 28, 2014. (2) P. M. Kirk. Mycol. Pap. 152:1, 1984. (3) G. Walther et al. Persoonia 30:11, 2013.

First Report of Anthracnose Caused by Colletotrichum lupini on Yellow Lupin in Korea

Yellow lupin (Lupinus luteus L.) is native to the Mediterranean region of southern Europe. In Korea, yellow lupins are cultivated for ornamental purposes. In May 2013, hundreds of yellow lupins that were grown in pots for 7 weeks in polyethylene-film-covered greenhouses were observed severely damaged by a previously unknown disease with about 30% disease incidence in a flower farm in Yongin City, Korea. Voucher specimens were deposited in the Korea University Herbarium (KUS). Early symptoms on petioles and stems appeared as small, slightly sunken, water-soaked, and circular spots. Lesions increased in size (4 to 12 μm in diameter), became more depressed, with a darkened central portion. As the disease progressed, affected areas sometimes girdled the stem and killed the shoot. Leaves were partly blighted, but less damaged. The darkened areas contained blackish acervuli from which masses of pale salmon-colored conidia were released in moist weather. Acervuli were circular to ellipsoid, 80 to 400 μm in diameter. Acervular setae were not observed. Conidia (n = 30) were long obclavate to oblong-elliptical, aguttulate, hyaline, and 10 to 18 × 3.6 to 5.2 μm with a length/width ratio of 2.6 to 3.6. Appressoria were single or occasionally in small dense clusters, medium brown, elliptical to round in outline with a smooth to lobate margin, and 8 to 14 × 6 to 9 μm. These characters were consistent with the description of Colletotrichum lupini (Bondar) Damm, P.F. Cannon & Crous (1,3). An isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC47254). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting 545-bp sequence was deposited in GenBank (Accession No. KJ447119). The sequence showed 100% identity with sequences of C. lupini (e.g., GenBank AJ301968, JN943480, JQ948162, and KF207599). To confirm pathogenicity, inoculum was prepared by harvesting conidia with sterile distilled water from 3-week-old cultures on potato dextrose agar. A conidial suspension (2 × 10⁵ conidia/ml) was sprayed until runoff onto the aerial parts of five healthy plants. Control plants were sprayed with sterile water. The plants were covered with plastic bags to maintain a relative humidity of 100% for 48 h and then transferred to a greenhouse. Typical symptoms of necrotic spots appeared on the inoculated leaves 6 days after inoculation, and were identical to the ones observed in the field. C. lupini was re-isolated from symptomatic leaf tissues. No symptoms were observed on control plants. The pathogenicity test was repeated twice. Anthracnose associated with C. lupini on lupins has been known from Europe (Germany, Ukraine, Austria, and Netherlands), North America (Canada and the United States), South America (Bolivia and Brazil), and Oceania (Australia and New Zealand) (2,4). To our knowledge, this is the first report of C. lupini on yellow lupins in Asia as well as in Korea. The presence of C. lupini on lupins in Asia can be considered as a potentially new and serious threat to this ornamental plant. References: (1) U. Damm et al. Stud. Mycol. 73:37, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved February 17, 2014. (3) H. I. Nirenberg et al. Mycologia 94:307, 2002. (4) E. Rosskopf et al. Plant Dis. 98:161, 2014.

First Report of White Blister Rust Caused by Albugo candida on Wasabi in Korea

Wasabi (Wasabia japonica (Miq.) Matsum.), a member of the Brassicaceae family, is a commercially important crop in East Asian countries such as China, Japan, Korea, and Taiwan. In Korea, wasabi is under commercial development since it has become popular as a condiment due to its strong pungent constituents. In May 2013, wasabi plants showing typical symptoms of white blister rust disease were first observed in plastic greenhouses in Taebaek City, Korea. Leaves of infected plants had whitish sori on the lower surfaces and chlorotic blotches on the corresponding upper leaf surfaces. Later, sori changed to creamy to light tan with necrosis of leaf lesion. New infections might occur anytime during the growing season. A representative sample was deposited in the Korea University Herbarium (KUS-F27596). Microscopic examination of fresh materials was performed under a light microscope. The grouped sporangiophores were hyaline, clavate or cylindric, and measured 20 to 35 × 10 to 14 μm. The sporangia were arranged in basipetal chains, hyaline, globose to subglobose, with uniform wall thickness and measured 16 to 21 × 13 to 18 μm. The primary sporangia were morphologically similar to the secondary sporangia, although the former exhibited a slightly thicker wall than the latter. No resting organs were observed. Previously, the white blister rust pathogen on wasabi has been considered either Albugo candida or A. wasabiae, although the latter name is often considered a synonym of A. candida. Based on the morphological characteristics and the specific host plant, the causal agent of this disease was identified as A. candida (2). To confirm this morphological identification, genomic DNA was extracted from infected plant tissue, and the amplification and sequencing of the internal transcribed spacer (ITS) region of rDNA of the Korean specimen were performed using procedures outlined by Choi et al. (1), with oomycete-specific primer set, DC6 and LR0. The resulting 835-bp sequence of the region was deposited in GenBank (Accession No. KF887494). Since this was the first ITS sequence submitted for A. candida on wasabi, comparable data were not available. A comparison with the ITS sequences available in the GenBank database revealed that it is identical to A. candida found on Capsella bursa-pastoris (AF271231), and shows a high similarity of 99% with many A. candida sequences originating from other brassicaceous plants. Therefore, the pathogen found in Korea was confirmed to be A. candida. In Korea, it has been reported that A. candida attacks Brassica juncea, B. campestris subsp. penikensis, and B. napus (3), but to our knowledge this is the first record of A. candida on wasabi (4). The white blister rust caused by A. candida is one of the most devastating diseases of wasabi in Japan and Taiwan where the crop is widely cultivated. On the other hand, in the United States, Canada, and New Zealand, where wasabi is a new crop on a commercial scale, there is no record of this disease. These facts taken together suggest that wasabi white blister rust be not only currently spreading in East Asia, but it also poses a new and serious threat to production of this crop in countries in which it is currently absent. References: (1) Y. J. Choi et al. Mol. Phylogenet. Evol. 40:400, 2006. (2) Y. J. Choi et al. Fungal Divers. 27:11, 2007. (3) Y. J. Choi et al. Plant Pathol. J. 27: 192, 2011. (4) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved November 15, 2013.

First Report of Powdery Mildew Caused by Erysiphe heraclei on Chervil in Korea

Chervil (Anthriscus cerefolium (L.) Hoffm.), belonging to the family Apiaceae, is an aromatic annual herb that is native to the Caucasus. It is widely used as a flavoring agent for culinary purposes. This herb was recently introduced in Korea. In April 2013, plants showing typical symptoms of powdery mildew disease were observed in a polyethylene film-covered greenhouse in Seoul, Korea. White mycelium bearing conidia formed irregular patches on leaves and stems. Mycelial growth was amphigenous. Severe infections caused leaf withering and premature senescence. Voucher specimens were deposited in the Korea University Herbarium (KUS). Hyphae were septate, branched, with moderately lobed appressoria. Conidiophores presented 3 to 4 cells and measured 85 to 148 × 7 to 9 μm. Foot-cells of conidiophores were 37 to 50 μm long. Conidia were produced singly, oblong-elliptical to oblong, measured 30 to 50 × 13 to 18 μm with a length/width ratio of 2.0 to 3.3, lacked conspicuous fibrosin bodies, and with angular/rectangular wrinkling of the outer walls. Germ tubes were produced in the subterminal position of conidia. Chasmothecia were not found. These structures are typical of the powdery mildew Pseudoidium anamorph of the genus Erysiphe. The specific measurements and morphological characteristics were consistent with those of E. heraclei DC. (1). To confirm identity of the causal fungus, the complete internal transcribed spacer (ITS) region of rDNA of KUS-F27279 was amplified with primers ITS5 and P3 (4) and sequenced directly. The resulting 561-bp sequence was deposited in GenBank (Accession No. KF111807). A GenBank BLAST search of this sequence showed >99% similarity with those of many E. heraclei isolates, e.g., Pimpinella affinis (AB104513), Anethum graveolens (JN603995), and Daucus carota (EU371725). Pathogenicity was confirmed through inoculation by gently pressing a diseased leaf onto leaves of five healthy potted chervil plants. Five non-inoculated plants served as a control treatment. Plants were maintained in a greenhouse at 22 ± 2°C. Inoculated plants developed signs and symptoms after 6 days, whereas the control plants remained healthy. The fungus present on the inoculated plants was identical morphologically to that originally observed on diseased plants. Chervil powdery mildews caused by E. heraclei have been reported in Europe (Bulgaria, France, Germany, Hungary, Italy, Romania, Switzerland, and the former Soviet Union) and the United States (2,3). To our knowledge, this is the first report of powdery mildew caused by E. heraclei on chervil in Asia as well as in Korea. The plant is cultivated in commercial farms for its edible leaves in Korea. Occurrence of powdery mildew is a threat to quality and marketability of this herb, especially those grown in organic farming where chemical control options are limited. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11, CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Syst. Mycol. Microbiol. Lab., Online publication. ARS, USDA. Retrieved July 29, 2013. (3) S. T. Koike and G. S. Saenz. Plant Dis. 88:1163, 2004. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.