Biphasic Reactions Research Articles

Impact of Treatment on Rate of Biphasic Reaction in Children with Anaphylaxis

Objective: Our goal was to characterize a large group of children presenting to the emergency department (ED) with acute anaphylaxis, treated with intramuscular epinephrine (IM EPI) and a corticosteroid (CS), and to determine the impact of pharmacologic intervention on the rate and timing of biphasic reactions (BPR). Methods: We reviewed consecutive children diagnosed with acute anaphylaxis managed in three EDs during a six-year period. All received IM EPI and CS, followed by monitoring for 4–6 hours post-treatment. We analyzed the rate and timing of BPR, comparing the intervals of 0–4vs4–48 hours after initiating therapy. Results: During the study period, there were 371 cases of anaphylaxis, of which 357 (94%) received both IM EPI and CS. Of these, 49 (14%) manifested BPR [84% had received prehospital IM EPI] requiring at least one additional dose of IM EPI [14% required ≥2 additional doses]. All BPR episodes occurred within the 0–4 hour interval after initiating therapy, whereas no patient manifested a BPR requiring an additional dose of IM EPI during the 4–48 hours after initiating therapy (P =<0.001, 95% CI 0–1.3%). No patient returned to the ED with recurrence of anaphylaxis symptoms within 48 hours after discharge. Conclusion: Approximately 1 in 7 children with anaphylaxis experience a biphasic reaction after receiving intramuscular epinephrine. Children with anaphylaxis who exhibit symptomatic resolution four hours following initiation of therapy have a low risk for subsequently developing BPR. Most BPR cases required only one additional dose of IM EPI to effect resolution. The rate of BPR in those receiving IM EPI and a corticosteroid is significantly lower >4 hours vs <4 hours after initiating therapy.

Unveiling the Influence of Water Molecules on the Structural Dynamics of Prussian Blue Analogues.

3D-framework Prussian blue analogues (PBAs) are appealing as a cost-effective, sustainable cathodes for Na-ion batteries. However, the aqueous-based synthesis of PBAs inherently introduces three different forms of water molecules (surface, interstitial and crystal) into the structure. Removal of water molecules causes phase transformation from monoclinic (M) to rhombohedral (R). This work presents the effects of water molecules on the structure before the phase transformation temperature, employing two promising PBA cathodes, Na2Fe[Fe(CN)6]·1.69H2O and Na2Mn[Fe(CN)6]·1.76H2O. Specifically, the water molecules impact the molecular interactions at the local structure and the electrochemical properties. This work has performed calculations on low-vacancy Na2M[Fe(CN)6] PBAs (where M = Mn, Fe, Co, Ni and Cu) to understand the dehydration energy. Employing in situ high-temperature X-ray diffraction and Raman spectroscopy, this work observes that water removal induces negative thermal expansion and stronger interactions between C≡N and Na ions, resulting in biphasic reactions with sluggish kinetics. Additionally, water molecules play a role in maintaining the open 3D tunnels and facilitating a solid-solution like insertion of Na ions. Calculated phonon-Raman spectra provide insights into cyanide group deformations, revealing the interactions between water molecules, alkali-ions, and transition-metal ions. This study enhances the understanding of the relationship among electronic, vibrational, and electrochemical properties.

CO2/N2 Triggered Aqueous Recyclable Surfactants for Biphasic Catalytic Reactions in the Pickering Emulsions.

The utilization of Pickering emulsions in interfacial catalysis offers a promising environmental platform for biphasic reactions. However, complicated surface coating or chemical grafting methods are always required to prepare the surface-active catalysts for the Pickering emulsions, since most of them are commercially unavailable. Here, we report CO2-switchable Pickering emulsions for biphasic reactions, in which Pd@Al2O3 nanoparticles are in situ modified by a CO2/N2 responsive surfactant. Compared with the chemical grafted methods, the in situ formed Pickering interfacial catalysts avoid complex chemical modification. Furthermore, efficient demulsification and separation of the oil phase and the products without surfactant contaminations can be achieved by CO2 trigger. The Pickering interfacial catalysis system can also be reformed after the aqueous phase containing the catalyst nanoparticles, and the surfactant is recycled and reused. The strategy is universal for nitrobenzene reductions and alcohol oxidations, providing a convenient and green method for the preparation of Pickering catalysts with commercially available nanoparticles, efficient emulsion separation, and recovery of the catalyst nanoparticles and emulsifiers in various two-phase organic reactions.

Evaluating Practice Patterns of Observation Periods Following Epinephrine Administration for Anaphylaxis Among Pediatric Patients.

Objective Current guidelines recommend that anaphylactic patients be observed for 4-6 hours following epinephrine administration to monitor for biphasic reactions. There is conflicting data regarding the efficacy of these guidelines and the prevalence of biphasic reactions among the pediatric population. This retrospective study aimed to investigate the appropriateness of these guidelines through evaluation of observation periods and patterns of biphasic reaction development among pediatric anaphylactic patients at a single-institution ED. Methods Patients less than 18 years of age who presented to the ED of a tertiary academic medical center between 2017 and 2022 and were treated with epinephrine for anaphylaxis were included in the study. The frequency and timing of biphasic reactions were observed. Duration of ED observation, time between symptom onset and first dose of epinephrine, number and category of anaphylactic symptoms, and allergen type were compared between patients who did and did not experience a biphasic reaction. Additional variables analyzed included persistence of anaphylactic symptoms, additional doses of epinephrine, and adjuvant medications. Contingency tables and two-sample t-tests were used to compare categorical and continuous variables, respectively, between those who did and did not develop a biphasic reaction. Results A total of 292 patients met the inclusion criteria and were included in the analysis. All patients were observed in the ED for a mean of 233.1 minutes. Ten patients (3.4%) developed a biphasic reaction. Six had a reaction within 150 minutes of initial symptom resolution, and four developed one after discharge, within 10 to 33 hours following symptom resolution. There was no significant difference in the length of time observed in the ED (p=0.98) or from symptom onset to the first epinephrine dose (p=0.90) between groups. Presenting with respiratory symptoms was associated with persistent anaphylactic symptoms despite epinephrine administration (p=0.01). Patients with symptoms involving at least two organ systems were 3.45 times more likely to experience persistent symptoms post-epinephrine than those with involvement of only one organ system (OR=3.45; CI: 1.28-9.30). Allergen type, anaphylactic symptoms, or the number of organ systems involved were not linked to developing a biphasic reaction or the need for additional epinephrine doses. Conclusions The patients who developed a biphasic reaction did so either shortly following initial symptom resolution or many hours past the recommended observation period. Extending the observation period of patients within reasonable parameters would not have reduced the number of patients who experienced a biphasic reaction after discharge. The results of this study support potentially adopting a more individualized approach to anaphylaxis management following epinephrine administration. Shortening the observation period for patients at low risk for biphasic reactions could reduce the patient burden on EDs without negatively impacting patient outcomes. Although no significant risk factors for biphasic reactions were identified in this study, closer monitoring of patients with respiratory symptoms and/or involvement of a greater number of organ systems may help mitigate the number of patients who experience persistence of anaphylaxis despite treatment.

Outcomes associated with prehospital epinephrine in adult and pediatric patients with anaphylaxis

BackgroundPrompt epinephrine administration is important to improve outcomes in anaphylaxis. ObjectiveTo assess the impact of prehospital epinephrine on clinical outcomes of hospital admission, biphasic reactions, and emergency department (ED) length of stay (LOS) in a cohort of ED patients who had anaphylaxis including both children and adults. MethodsWe conducted a single-center prospective and retrospective cohort study of patients who had anaphylaxis from April 2008 to December 2022. Associations between prehospital epinephrine administration with biphasic reactions and ED LOS were assessed with univariable models and the association with ED disposition was assessed with both univariable and multivariable logistic regression. ResultsA total of 1107 patient visits were included for analysis. The median patient age was 29 (IQR: 14-50), 593 (53.6%) patients were of female sex, and 366 (33.1%) were younger than 18 years of age. Patients in the prehospital epinephrine group were also less likely to experience a biphasic reaction (5.4% vs 9.3%; odds ratio [OR] 0.56, 95% CI: 0.34-0.92) and had a decreased ED LOS (median 4.0 hours vs 4.7 hours). There was no difference in hospital admission between patients with and without prehospital epinephrine in both the univariable (19.5% vs 15.7%; OR 1.30, 95% CI: 0.94-1.79) and multivariable (adjusted OR 1.08, 95% CI: 0.71-1.64) models. ConclusionPrehospital epinephrine administration reduced the odds of a biphasic reaction and decreased ED LOS but did not reduce hospitalization in this cohort of ED patients who had anaphylaxis. Our findings suggest that timely administration of prehospital epinephrine is associated with improved patient outcomes.

Modeling and simulation of bi‐continuous jammed emulsion membrane reactors for enhanced biphasic enzymatic reactions

AbstractBi‐continuous jammed emulsion (bijel) membrane reactors, integrating simultaneous reaction and separation, offer a promising avenue for enhancing membrane reactor processes. In this study, we present a comprehensive macroscopic‐scale physicochemical model for tubular bijel membrane reactors and a numerical solution strategy for solving the governing partial differential equations. The model captures the co‐continuous network of two immiscible phases stabilized by nanoparticles at the liquid–liquid interface. We present the derivation of model equations and an efficient numerical solution strategy. The model is validated with experimental results from a conventional enzymatic biphasic membrane reactor for oleuropein hydrolysis, already reported in the literature. Simulation results indicate accurate prediction of reactor behavior, highlighting the potential superiority of bijel membrane reactors over current technologies. This research contributes a valuable tool for scale‐up, design, and optimization of bijel membrane reactors, filling a critical gap in this emerging field.

Lipase grafted on magnetic and CO2 dual-responsive Janus nanoparticles for interfacial catalyzed transesterification

Enzyme-loaded Pickering emulsions are a promising system for biphasic catalytic reactions. The monodisperse core-shell Janus nanoparticles (JNPs) P[xMAOAAO-yDEAEA]@RF@Fe3O4-CRL with magnetic and CO2 dual-responsiveness were synthesized by the wax/water emulsion. The catalysts can perfectly steady the oil/methanol Pickering emulsion and produce biodiesel by static transesterification of soybean oil. There is a synergistic effect between the interfacial activation of CRL realized by amphiphilic Janus supporters and the stability of the Pickering emulsions. Under optimal reaction conditions, the Pickering interfacial biocatalyst exhibits excellent enzymatic activity, reaching a biodiesel yield of 87.33 %. Furthermore, magnetic absorption and introduction of CO2 separate the catalyst P[2MAOAAO-DEAEA]@RF@Fe3O4-CRL from the system, and the biodiesel yield is 86.3 % after 6 cycles.

TEMPO immobilized polymeric Janus dumbbell: Assembly and catalysis at liquid-liquid interface

Pickering interfacial catalysts (PICs) have emerged as a promising solution for simultaneously enhancing and catalyzing liquid-liquid biphasic reactions. In this study, we successfully synthesized dumbbell-shaped Janus structured polymeric nanoparticles with one side anchored imidazolium-TEMPO (im-C4-TEMPO@JPP) as Pickering interfacial catalyst for the oxidation of alcohols using the Anelli-Montanari reaction system. In the Pickering emulsion system, the im-C4-TEMPO@JPPs particles are assembled at the W/O interface due to the hydrophilicity of imidazolium-TEMPO anchored lobe which enables excellent amphiphilic character of the polymeric Janus dumbbell. Moreover, the im-C4-TEMPO@JPPs particles reduce the interfacial tension from 27.82 to 18.43 mN/m. This excellent interfacial adsorption capacity of im-C4-TEMPO@JPPs strongly stabilizes the water/dichloromethane Pickering emulsion over two months (emulsion volume fraction >90 %), thus providing an efficient reaction platform for liquid-liquid biphasic reactions. As a result, the constructed Pickering emulsion system efficiently catalyzes the oxidation of cinnamyl alcohol to cinnamaldehyde under static conditions. After 1 hour of reaction, the conversion of cinnamyl alcohol achieved 97.1 % with a selectivity of 99 %, nearly the same level relative to stirring intensified biphasic reaction. Hence, this novel PIC effectively improves the efficiency and sustainability of liquid-liquid biphasic catalytic reactions.

Switchable CO2-Responsive Janus Nanoparticle for Lipase Catalysis in Pickering Emulsion.

The use of convertible immobilized enzyme carriers is crucial for biphasic catalytic reactions conducted in Pickering emulsions. However, the intense mechanical forces during the conversion process lead to enzyme leakage, affecting the stability of the immobilized enzymes. In this study, a CO2-responsive switchable Janus (CrSJ) nanoparticle (NP) was developed using silica NP, with one side featuring aldehyde groups and the other side adsorbing N,N-dimethyldodecylamine. A switchable Pickering emulsion catalytic system for biphasic interface reactions was prepared by covalently immobilizing lipase onto the CrSJ NPs. The CO2-responsive nature of the CrSJ NPs allowed for rapid conversion of the Pickering emulsion, and covalent immobilization substantially reduced lipase leakage while enhancing the stability of the immobilization during the conversion process. Impressively, after repeated transformations, the Pickering emulsion still maintains its original structure. Following 10 consecutive cycles of esterification and hydrolysis reactions, the immobilized enzyme's activity remains at 77.7 and 79.5% of its initial activity, respectively. The Km of the CrSJ catalytic system showed no significant change compared to the free enzyme, while its Vmax values were 1.2 and 1.6 times that of the free enzyme in esterification and hydrolysis reactions, respectively.

Incidence, predictors, and treatment outcomes of biphasic anaphylaxis in the emergency department of a tertiary hospital:A 5-year retrospective study.

Biphasic anaphylaxis despite successful treatment has an incidence of 4-5% based on NIAID/FAAN criteria. Our study aimed to investigate the frequency and predictive factors associated with biphasic reactions within the emergency department (ED) at Siriraj Hospital. This observational study assessed medical records of anaphylaxis and anaphylactic shock patients at Siriraj Hospital's ED from January 2015 to December 2019. Of these, a random sample was reviewed and validated by allergists. Telephone interviews were performed to collect more data. Uni- or biphasic response were analyzed descriptively. Prediction modeling was performed. Among 1888 ED anaphylaxis cases, 601 were randomly sampled; 239 patients completing interviews were analyzed. The incidence of biphasic reactions was 7.1% (17/239) of cases. Common triggers of biphasic responses were foods (57.7%), drugs (31%), other known allergens (5.9%). Shellfish, edible insects, and wheat were the leading food triggers. Biphasic responses were significantly associated with history of drug allergy, any allergic disease, allergic rhinitis, number of prior anaphylactic reactions, angioedema, less generalized erythema, less reaction to shellfish, reaction to NSAIDs, and no epinephrine giving at ED visit (all p < 0.1). From a 3-predictor prognostic model including drug/idiopathic reaction, duration from onset to first epinephrine > 60 minutes, and any cutaneous edema/angioedema with an area under the curve of 0.72 (95%CI 0.54, 0.90). The incidence of biphasic response was 7.1%. Predictors of biphasic response were drug/idiopathic reac- tion, any cutaneous edema/angioedema, and time from onset to first epinephrine > 60 minutes.

Amplifying the electrochemical footprint of

The ability of analytical strategies to detect and positively identify molecules under extremely dilute conditions is important for the growth and expansion of analytical techniques and instrumentation. At present, few measurement science techniques can robustly approach the measurement of just a few thousand molecules. Here, we present an electrochemical platform for the detection and positive identification of fewer than 1000 molecules of decamethylferrocene ((Cp*)2FeII). We achieve this remarkable detection threshold by trapping (Cp*)2FeII in a 1,2-dichloroethane microdroplet, which is allowed to dissolve into an aqueous continuous phase while on a gold microelectrode (radius ∼6.25 μm). Because electrochemistry is not sensitive enough to observe the charge of less than 1000 molecules, we dissolved μM amounts hexacyanoferrate(III) in the aqueous continuous phase. The biphasic reaction between hexacyanoferrate(III) and Cp2*(Fe)II allows for a feedback loop when the microelectrode is biased sufficiently negative to reduce Cp2*(Fe)III. This feedback loop, a typical EC' catalytic mechanism, amplifies the electrochemical signal of Cp2*(Fe)II when the droplet is of small enough dimensions for feedback to occur. Our results demonstrate that clever biphasic reactions can be coupled with dissolving microdroplets to access extremely low limits of quantitation in electroanalysis.

Anaphylaxis in children: Effect of age and atopic status.

Anaphylaxis is a life-threatening allergic reaction with rising incidence worldwide. Young children's limited ability to express symptoms adds unique diagnostic challenges. To study on anaphylaxis in children, including triggers, symptoms, treatment, atopic status impact, and adrenaline injection time intervals. In-patient medical records of children who were diagnosed with anaphylaxis during 2014-2021 were reviewed. One hundred thirty-three anaphylaxis events were identified. Food (47%) was the most common trigger, followed by drugs (31%), blood components (17%), insects (3%), and idiopathic causes (2%). Ten cases of refractory anaphylaxis, 2 cases of biphasic reactions, and 1 case of persistent anaphylaxis were found. There were no reported fatalities. The most common presentations involved the skin (94%), followed by the respiratory (73%), gastrointestinal (47%), and cardiovascular (42%) systems. In atopic patients, wheezing was more prominent than in those without atopy (p-value = 0.017). In the non-atopic patients, there was a higher incidence of cardiovascular symptoms, particularly hypotension (p-value = 0.001), compared to individuals with atopy. Children under 5 years old with mild-moderate anaphylaxis required more time to reach the hospital (147.0 vs. 45.0 minutes, p = 0.033) and to receive adrenaline injections (35.0 vs. 9.0 minutes, p-value = 0.017) than those with severe anaphylaxis. Childhood anaphylaxis is prevalent. Children with mild-moderate anaphylaxis experienced delays in hospital visits and adrenaline administration. Education on allergies is needed to improve the identification and prompt response to anaphylactic reactions, especially in young children.

D-Idose-Based Monoaza-15-Crown-5 Lariat Ethers: Synthesis of an Elusive d-Hexose and Application of Derived Macrocycles in Enantioselective Syntheses

Carbohydrate-based macrocycles can be enantioselective catalysts in certain reactions. Previously, it was proven that the carbohydrate moiety could affect the catalytic activity of the monoaza-15-crown-5 type macrocycles derived from sugars. According to our experiments so far, the most effective enantioselective catalysts were the d-glucose- and the d-galactose-based crown ethers. To obtain more information about the effect of the carbohydrate unit, a rare monosaccharide, d-idose was incorporated into the monoaza-15-crown-5 structure. The key intermediates were methyl 4,6-O-benzylidene-α-d-idopyranoside and methyl 4,6-O-benzylidene-β-d-idopyranoside, which were synthesized from d-galactose. The efficiency of the idopyranoside-based crown compounds synthesized was investigated in asymmetric phase transfer reactions. In liquid-liquid biphasic reactions the highest enantioselectivity was 81% ee, while in solid-liquid phase systems the highest asymmetric induction was 67% ee. It was observed that the enantiodiscrimination was strongly dependent on the configuration of the anomeric center, on the side arm of the nitrogen, and on the structure of the substrate.

A Medium‐Entropy Phosphate Cathode with Multielectron Redox Reaction for Advanced Sodium‐Ion Batteries

AbstractAchieving multi‐sodium storage and high operating voltage is key to boosting energy density of NASICON‐type materials. However, the activation of more redox couples is usually accompanied by asymmetric and irreversible electrochemical reactions, thus causing fast capacity fading. To address this issue, a medium‐entropy concept is proposed, and a novel medium‐entropy Na3Mn2/3V2/3Ti2/3(PO4)3/C@CNTs (ME‐NMVTP) cathode is designed. The as‐prepared ME‐NMVTP achieves a successive redox reaction, delivering a highly reversible specific capacity of 147.9 mA h g−1 at 50 mA g−1 together with a long‐term lifespan of 1000 cycles at 500 mA g−1 (capacity retention of 88.3%), which is superior to low‐entropy cathodes such as Na4MnV(PO4)3/C@CNTs (LE‐NMVP) and Na3MnTi(PO4)3/C@CNTs (LE‐NMTP). Moreover, benefiting from the entropy effect, solid‐solution and biphasic reactions with reversible structure evolution and small volume change are achieved during the multi‐sodium storage process. First‐principles calculation and kinetic analysis results affirm the enhanced electronic conductivity and facilitated Na+ migration of the ME‐NMVTP cathode derived from the synergistic effect of the three transition‐metal elementals in a medium‐entropy crystalline state. The strategy of engineering medium‐entropy to construct cathodes with superior performance is expected to be widely applicable to other electrode materials.

Amphiphilic heteropolyacid-based sulfonic acid-functionalised ionic liquids as efficient catalysts for biodiesel production

Aiming to address the mass transfer limitation in biphasic transesterification reactions for biodiesel production, as well as the poor affinity between conventional catalysts and feedstock oils, a series of amphiphilic heteropolyacid-based sulfonic acid-functionalised ionic liquids (AHPA-SFILs) were synthesised. Impressively, the solid-state AHPA-SFILs as catalysts would dissolve in the reaction medium during the transesterification of palm oil with methanol, enabling efficient homogeneous catalysis. Subsequently, the AHPA-SFILs could be easily precipitated and recovered by evaporating the methanol. Under the reaction temperature of 140 °C, methanol/oil molar ratio of 20, catalyst dosage of 7 wt%, and reaction time of 1.8 h determined by response surface methodology, the optimum AHPA-SFIL, namely [C16N-‍PS]-HPMo-1, exhibited a 95.86% yield of biodiesel. As revealed by experiments and quantum chemical calculations, the C16 chain of [C16N-PS]-HPMo-1 on one hand enhanced the mass transfer by promoting the dissolution of methanol in oil phase, and on the other hand facilitated the enrichment of triglycerides through intensified van der Waals interaction, thereby triggering the remarkable catalytic performance. This reaction intensification effect derived from long alkyl groups provided a theoretical basis for the design of future ILs. Furthermore, [C16N-PS]-HPMo-‍1 AHPA-SFIL showed satisfactory generality in the biodiesel production from different oils, signifying its promising application potential.

Unexpected Kinetic Solvent Effects Enhance Activity and Selectivity in Biphasic Systems

Biphasic dehydration of fructose to 5-hydroxymethylfurfural (HMF) has shown unprecedented increases in productivity, but a mechanistic understanding is lacking. Herein, we couple fast experimental reaction kinetics, multiscale modeling (phase behavior, classical molecular dynamics(MD), and quantum mechanics/molecular mechanics MD), in situ sampling, and IR and 13C-NMR spectroscopy to elucidate the complex effects of nonpolar extracting organic solvents on the kinetics of fructose dehydration. We show that these organic solvents can reach significant mutual solubility with water at reaction temperatures, enabling the partition of the sugar and catalyst into the extracting phase. In the organic-rich environment, the dehydration of fructose proceeds faster and more selectively than in water due to increased relative abundance of the reactive furanose isomer, enhanced water–catalyst–substrate interactions driven by nanophase separation, and higher product stability stemming from preferential solvation. We demonstrate that these solvent effects impact other critical biphasic reactions in biomass upgrading and provide qualitative principles for solvent selection.

Fast Isomerization Before Isomerization‐Hydroformylation: Probing the Neglected Period with A Novel Microfluidic Device

AbstractBy combining the concept of flash chemistry and radial synthesis, a novel microreactor (Flashstop reactor) was designed to study isomerization process of hydroformylation by a Rh/tetraphosphite catalyst in a time scale of seconds. It was found that in the initial 313 seconds, 60–99 % of 1‐octene was isomerized to 2‐ and 3‐octenes before the formation of aldehydes. Within this period, two different types of isomerization reactions were observed. It was proposed that a monohydride complex without CO ligand accounts for the ultrafast isomerization in the initial 30 seconds. The isomerization rate with such monohydride species was calculated much faster than that with the well‐known H(CO)Rh(P−P) species. Both experimental and DFT computational studies were carried out to support this assumption. Fast transformations early on in catalytic cycles have been rarely studied due to the lack of proper tools. We believe that the Flashstop reactor is a powerful tool for analysis of kinetics in gas‐liquid biphasic reactions within a time scale of seconds to minutes.

Fast Isomerization Before Isomerization-Hydroformylation: Probing the Neglected Period with A Novel Microfluidic Device.

By combining the concept of flash chemistry and radial synthesis, a novel microreactor (Flashstop reactor) was designed to study isomerization process of hydroformylation by a Rh/tetraphosphite catalyst in a time scale of seconds. It was found that in the initial 313 seconds, 60~99% of 1-octene was isomerized to 2- and 3-octenes before the formation of aldehydes. Within this period, two different types of isomerization reactions were observed. It was proposed that a monohydride complex without CO ligand accounts for the ultrafast isomerization in the initial 30 seconds. The isomerization rate with such monohydride species was calculated much faster than that with the well-known H(CO)Rh(P-P) species. Both experimental and DFT computational studies were carried out to support this assumption. Fast transformations early on in catalytic cycles have been rarely studied due to the lack of proper tools. We believe that the Flashstop reactor is a powerful tool for analysis of kinetics in gas-liquid biphasic reactions within a time scale of seconds to minutes.

Regioselective Surface Assembly of Mesoporous Carbon on Zeolites Creating Anisotropic Wettability for Biphasic Interface Catalysis

The anisotropic surface functionalization of microporous zeolites with mesoporous materials into hierarchically porous heterostructures with distinctive physical and chemical properties is expected to significantly extend their applicability to catalysis. However, the precise control of the surface chemistry of zeolite crystals through site-specific interconnection with mesoporous materials remains a grand challenge. Here, we report a regioselective surface assembly strategy for the region-specific growth of mesoporous polymer/carbon on zeolite nanocrystals. The approach enables controllable regioselective surface deposition of mesoporous polydopamine on the edges, curved surfaces, or/and flat surfaces of the silicalite-1 nanocrystals into exotic hierarchical nanostructures with diverse surface geometries. Upon carbonization, their derived heterostructures with anisotropic surface wettability show amphiphilic properties. As a proof of concept, Pt nanoparticle-encapsulated silicalite-1/mesoporous carbon nanocomposites are tested to be interface-active for forming Pickering emulsions. Significantly, the catalysts show superior catalytic performance in shape-selective hydrogenation of various nitroarenes in a series of biphasic tandem catalytic reactions, giving ∼100% yield of corresponding amine products. The results pave a path toward rational construction of high levels of surface structural complexity in hierarchically porous heterostructures for specific physical and chemical characteristics in diverse applications.

Retire the advice to send patients to the emergency department after epinephrine use for observation

Food allergy action plans state that if epinephrine is administered to “immediately call 911 and seek care in the nearest medical facility.”1 Such guidance has been based on expert opinion given the risk of persistent (eg, refractory) or biphasic reactions after initial epinephrine use. In addition, practitioners, health care organizations, and policy groups are cognizant of potential litigation if patients have adverse outcomes associated with anaphylaxis management, despite following treatment protocols.