Biphasic Reactions Research Articles

Ultrasmall amphiphilic zeolitic nanoreactors for the aerobic oxidation of alcohols in water.

Organic reactors in a green solvent (water) is the goal of sustainable development. Green nanoreactors with excellent amphiphilicity and catalytic activity are strongly desired. Herein, a novel amphiphilic nanoreactor Pd@amZSM-5 with ultrasmall size has been successfully synthesized via a simple one-step oil bath method, subjected to the modification-etching-modification strategy and in situ reduction of Pd2+. Ultrasmall Pd@amZSM-5 nanoreactors (60 nm) with hierarchical structures showed outstanding amphiphilicity for forming Pickering emulsions with fine uniform droplets (50 μm). Fine droplets formed short diffusion distances, which can significantly improve the catalytic activity in biphasic reactions. Moroever, the ultrasmall Pd@amZSM-5 nanoreactors demonstrated excellent catalytic activity for the selective oxidation of alcohols in water using air as the oxidant. Alkali was not present in the reaction system. The hydrophilic aminopropyl groups on the surface of the Pd@amZSM-5 nanoreactors not only changed the affinity of the zeolite surface and provided targeting points for Pd nanoparticles but also provided an alkaline environment for the selective oxidation of alcohols. The ultrasmall Pd@amZSM-5 nanoreactors presented excellent universality for aromatic alcohols (with >90% conversion and >90% selectivity) and allylic alcohols (with 100% conversion and 100% selectivity).

Amphiphilic confined Pt-based nanocatalysts produced by atomic layer deposition with enhanced catalytic performance for biphasic reactions

Confined catalysts with different wettability microenvironments are designed. The amphiphilic microenvironment in nanochannels simultaneously promotes the transport of reactants to active sites and thus improves the performance in biphasic reactions.

The 2020 update on anaphylaxis in paediatric population.

The objective of the review is to present recent updates on anaphylaxis in paediatric population worldwide. The article summarizes the results of epidemiological studies, diagnostic methods and treatments. We present a new WAO definition of anaphylaxis (2019), which broader criteria excluding dermal symptoms should facilitate faster life-saving adrenaline use. Adrenaline remains the best treatment to manage severe symptoms and to prevent biphasic reactions. There is ongoing effort to increase adrenaline use, such as modified autoinjectors, individual training, and diversified dosing. There are five independent risk factors of lethal anaphylaxis in children, including history of asthma, almost immediate onset of symptoms, unwell appearance, tachycardia and hypotension. We also report improvements in diagnostics, like component-resolved diagnostics, and novel therapies stimulating immunotolerance. We signal the development of ICD-11 with updated coding of anaphylaxis, which corresponds better to clinical observations.

Hypersensitivity Reactions and Anaphylaxis

Allergic reactions vary in intensity from mild rash or allergic rhinitis to devastating anaphylactic shock. Anaphylaxis, often underrecognized and undertreated, can be a life-threatening syndrome leading to multiorgan dysfunction. This review covers the etiology, pathophysiology, and treatment of severe allergic reactions and anaphylaxis. It is precipitated by exposure to particular allergens—commonly food, medications, insect stings, and environmental exposures—in a previously sensitized individual. Symptoms develop from an IgE-mediated immune response leading to degranulation of mast cells and basophils and the release of preformed mediators, lipid-derived metabolites, and inflammatory cytokines. First-line treatment for anaphylaxis involves epinephrine. Secondary treatments are antihistamines and corticosteroids. Further treatments for patients refractory to standard therapies involve vasopressor agents, nebulized albuterol, and glucagon. Frequency and duration of biphasic reactions are variable, limiting the development of consensus guidelines for monitoring of anaphylactic reactions. Figures show the immune activity and inflammatory pathways in allergic responses, mast cell degranulation, and a depiction of common organs involved and corresponding clinical manifestations. Tables list the criteria for diagnosis of anaphylaxis, classification of hypersensitivity reactions, common clinical manifestations, and etiology and mediators of anaphylaxis. This review contains 4 highly rendered figures, 11 tables, and 43 references. Key words: allergy, anaphylaxis, antihistamine, corticosteroid, epinephrine, mast cells

Integrated fast-mass transfer and high Ti-sites utilization into hybrid amphiphilic TS@PMO catalyst towards efficient solvent-free methyl oleate epoxidation

For solvent-free catalytic oxidations, low efficiency resulted from poor mass transfer and insufficient utilization of active centers remains a tough problem. Herein, we demonstrate a novel hybrid core-shell catalyst (TS@PMO) with an amphiphilic shell and a Ti-surface-enriched mesoporous TiO2-SiO2 (TS) core to address this challenge. Such TS@PMO realizes its amphiphilicity via an ex situ formed periodic mesoporous organosilica (PMO) shell. Simultaneously, by a unique etching effect induced by organic precursor growth on [SiO4] tetrahedra in TS core, active Ti sites are facilely enriched in near-surface layer of core and extra mesoporous cavities are introduced for substrate reservation. When applied for solvent-free epoxidation of methyl oleate (MO) with H2O2, TS@PMO exhibits remarkably boosted catalytic activity (X = 90.2%) and epoxide selectivity (S = 70.2%), overwhelming the unmodified titanosilicate (X = 63.7%, S = 49.2%) and Ti-containing organosilica (X = 39.8%, S = 25.0%). Such result benefits from an evidently enhanced interphase mass transfer and sufficiently accessible active Ti sites in TS@PMO. On the one hand, amphiphilic PMO shell can efficiently collect hydrophobic substrate and H2O2, while abundant mesopores in the shell offer open-path for them to access active sites in the core; on the other hand, an increased framework Ti (IV) density and their surface-enrichment in TS core greatly improve the utilization of active Ti sites. This study effectively makes up for the deficiencies of slow mass transfer and insufficient utilization of conventional titanosilicates in biphasic reactions, which paves a new avenue to exploit other hybrid catalysts for high-efficiency solvent-free catalysis.

Characteristics of Anaphylactic Reactions: A Prospective Observational Study in Japan.

Anaphylaxis is a systemic, life-threating, allergic reaction in which the clinical features may vary in different populations or due to the allergic triggers. Moreover, the timing and characteristics of biphasic anaphylactic reactions remain unclear. The purpose of this study was to investigate the clinical characteristics of anaphylaxis cases assessed and treated in Japanese hospitals. This was a prospective observational study of anaphylactic reactions treated in the Emergency Department (ED) of two medical centers from June 2016 to May 2019. All patients diagnosed with anaphylaxis were enrolled in this study. Data collected included patient demographics, symptoms and signs, treatment, clinical course, and suspected triggers. Descriptive statistics and univariate methods were used in the analyses. We enrolled 302 patients. The median age was 32years (interquartile range 13-37) and the sample included 182 (60.3%) women. Of the 302 patients, 179 (59.3%) had a history of allergic reactions. The dermatologic, respiratory, gastrointestinal, and cardiac systems were involved in 297 (98.3%), 248 (82.1%), 150 (49.7%), and 55 (18.2%), respectively. Nineteen patients (6.3%) experienced biphasic anaphylactic reactions. Epinephrine use was associated with a lower incidence of biphasic anaphylactic reaction (odds ratio 0.3, 95% confidence interval 0.1-0.9). Time to recurrence of symptoms ranged from 2 to 48h (median: 10h). In this prospective ED study, foods were the most common triggers of anaphylaxis, and epinephrine administration was associated with a decreased occurrence of biphasic anaphylactic reactions. Over half of patients experiencing biphasic anaphylactic reactions developed symptoms more than 10h after presentation.

Blockade of Brain Adrenoreceptors Delays Seizure Development during Hyperbaric Oxygen Breathing

The main prodromal sign of seizures developing when breathing hyperbaric oxygen is a high activity of sympathetic outflow, as manifested in altered external respiration, impaired cardiac and vascular activity. We tested the hypothesis that the brain adrenergic receptors, as part of the central adrenergic system, are involved in the development of sympathetic hyperactivity and generalized seizures during hyperbaric oxygen breathing. In experiments on rats, α- and β-adrenoreceptors were blocked by non-selective and selective antagonists (propranolol, atenolol, phentolamine and prazosin) injected into the cerebral ventricles. Reactions of the CNS and autonomic nervous system to oxygen breathing at 5 ATA were evaluated. We found that in animals with intact adrenoreceptors, hyperbaric oxygen caused convulsions preceded by biphasic reactions of the cardiovascular system, external respiration and cerebral blood flow. All antagonists used in experiments attenuated visceral reactions and the development of oxygen convulsions, although propranolol showed most pronounced antihypertensive and anticonvulsant properties. The data obtained indicate the involvement of brain adrenergic receptors in the ANS reactions to hyperoxia and in the mechanisms underlying the development of oxygen seizures during hyperbaric oxygen breathing. Our results can be used to develop new methods for the prevention of seizures under extreme hyperoxia and to ensure the safe use of hyperbaric oxygen in clinical practice and diving.

Persistent, refractory, and biphasic anaphylaxis: A multidisciplinary Delphi study

The use of inconsistent definitions for anaphylaxis outcomes limits our understanding of the natural history and epidemiology of anaphylaxis, hindering clinical practice and research efforts. Our aim was to develop consensus definitions for clinically relevant anaphylaxis outcomes by utilizing a multidisciplinary group of clinical and research experts in anaphylaxis. Using Delphi methodology, we developed agenda topics and drafted questions to review during monthly conference calls. Through online surveys, a 19-member panel consisting of experts in allergy and/or immunology and emergency medicine rated their level of agreement with the appropriateness of statements on a scale of 1 to 9. Amedian value of 1.0 to 3.4 was considered inappropriate, a median value of 3.5 to 6.9 was considered uncertain, and a median value of 7.0 to 9.0 was considered appropriate. Adisagreement index was then calculated, with values less than 1.0 categorized as "consensus reached." If consensus was not reached after the initial survey, subsequent surveys incorporating the aggregate de-identified responses from prior surveys were sent to panel members. This process was repeated until consensus was reached or 4 survey rounds had been completed, after which the question was categorized as "no consensus reached." The panel developed outcome definitions for persistent, refractory, and biphasic anaphylaxis, as well as for persistent and biphasic nonanaphylactic reactions. There was also consensus among panel members regarding the need to develop an anaphylaxis severity grading system. Dissemination and application of these definitions in clinical care and research will help standardize the terminology used to describe anaphylaxis outcomes and serve asthe foundation for future research, including research aimedat development of an anaphylaxis severity grading system.

Emergence and Rearrangement of Dynamic Supramolecular Aggregates Visualized by Interferometric Scattering Microscopy.

Studying dynamic self-assembling systems in their native environment is essential for understanding the mechanisms of self-assembly and thereby exerting full control over these processes. Traditional ensemble-based analysis methods often struggle to reveal critical features of the self-assembly that occur at the single particle level. Here, we describe a label-free single-particle assay to visualize real-time self-assembly in aqueous solutions by interferometric scattering microscopy. We demonstrate how the assay can be applied to biphasic reactions yielding micellar or vesicular aggregates, detecting the onset of aggregate formation, quantifying the kinetics at the single particle level, and distinguishing sigmoidal and exponential growth of aggregate populations. Furthermore, we can follow the evolution in aggregate size in real time, visualizing the nucleation stages of the self-assembly processes and record phenomena such as incorporation of oily components into the micelle or vesicle lumen.

Risk Factors and Characteristics of Biphasic Anaphylaxis

Anaphylaxis is an immediate hypersensitivity reaction. However, a biphasic course with the second onset of symptoms can occur hours after the initial phase. Little is known about the causes of biphasic anaphylaxis making the identification of patients at risk difficult. To identify factors predisposing for biphasic anaphylaxis for the better understanding of these reactions. Data from the Anaphylaxis Registry (from 11 countries) including 8736 patients with monophasic and 435 biphasic anaphylaxis were analyzed. The rate of biphasic reactions in this large cohort was 4.7%. The identified risk factors were reaction severity (grade III/IV vs grade II: odds ratio [OR]= 1.34; 95% confidence interval [CI]: 1.1-1.62); multiorgan involvement; skin, gastrointestinal, severe respiratory, and cardiac symptoms; anaphylaxis caused by peanut/tree nut (OR= 1.78; 95% CI: 1.38-2.23) or an unknown elicitor (OR= 1.96; 95% CI: 1.41-2.72); exercise as a cofactor (OR= 1.44; 95% CI: 1.17-1.78); chronic urticaria as a comorbidity (OR= 2.12; 95% CI: 1.19-3.78); a prolonged interval between the contact with the elicitor and start of primary symptoms (OR for >30 vs <30 min: 1.38; 95% CI: 1.08-1.76); and antihistamine treatment (OR=1.52; 95% CI: 1.14-2.02). A biphasic course of anaphylaxis occurs more frequently in severely affected patients with multiorgan involvement. However, we identified multiple additional predictors, suggesting that the pathogenesis of biphasic reactions is more complex than being a rebound of a severe primary reaction.

Enzyme-Adsorbed Chitosan Nanogel Particles as Edible Pickering Interfacial Biocatalysts and Lipase-Responsive Phase Inversion of Emulsions.

Here, a simple food-grade Pickering emulsion system is prepared and adopted for biphasic biocatalytic reactions. The chitosan nanogels were prepared with strong dispersion of chitosan aggregates approaching neutral pH and then used as the particle emulsifiers to produce oil-in-water Pickering emulsions. The chitosan nanogel exhibited high affinity to negatively charged lipase. As a result of increasing the biphasic interfacial area and loading amount on the oil-water interface, the catalysis activity of lipase and recycling and pH stability were highly enhanced through colorimetric determination of p-nitrophenol (the hydrolysis product of p-nitrophenyl palmitate). A general strategy was proposed to obtain stimulus-responsive Pickering emulsions that can undergo phase inversion. The in situ modification of the wettability of chitosan nanogel could be attributed to the interaction between nanogel and free fatty acids, which was triggered by lipase hydrolysis. This would permit a rapid and controlled release of hydrophobic active components in response to enzymatic triggers.

Risk Factors for Severe Anaphylaxis in Children

To identify risk factors associated with severe anaphylaxis in children. We carried out a multicenter prospective observational study including children less than 18years old diagnosed with anaphylaxis in 7 Spanish pediatric emergency departments (EDs) between May 2016 and April 2018. Children were considered to have severe anaphylaxis if they met one or more of the following criteria: requirement for 2 or more doses of epinephrine, clinically important biphasic reaction, endotracheal intubation, intensive care unit admission, and/or death. We included 453 episodes of anaphylaxis. Of these, 61 were classified as severe anaphylaxis (13.5%, 95% CI [10.6-16.9]): 53 (11.7%) required more than 1 dose of epinephrine, and there were 14 (3.1%) cases of clinically important biphasic reactions, 2 (0.4%) intubations in the ED, and 6 (1.3%) admissions to the intensive care unit. No patients died. In the multivariable regression, we identified 5 independent risk factors for severe anaphylaxis: history of asthma (P=.002; OR 2.705, 95% CI [1.431-5.113]), onset of the symptoms less than 5minutes after the allergen exposure (P=.002; OR 2.619, 95% CI [1.410-4.866]), non-well appearance (P=.005; OR 2.973, 95% CI [1.380-6.405]), tachycardia (P=.014; OR 2.339, 95% CI [1.191-4.959]), and hypotension (P=.036; OR 3.725, 95% CI [1.087-12.762]). Childhood anaphylaxis is usually well controlled in the ED. Children with a history of asthma, rapid onset of the symptoms, who are non-well appearing, or have tachycardia or hypotension upon arrival to the ED are more likely to have severe episodes.

Scaling continuous API synthesis from milligram to kilogram: extending the enabling benefits of micro to the plant

The signature benefits of continuous flow are largely a result of a reactor’s micro-sized features. However, as the technology gains industrial traction in the synthesis of active pharmaceutical ingredients (API), the reactors must be scaled to larger size to meet production demands. Often, the micro-features cannot be preserved, and thus the challenge is in transferring the benefits of micro to the pilot plant and beyond. This review presents solutions to typical problems encountered in plug flow reactors (PFR) related to heat transfer, mixing, handling biphasic reactions, and photochemistry. Lessons are taken from kilogram level syntheses developed in pharmaceutical process chemistry groups.

Coffee Melanoidin‐Based Multipurpose Film Formation: Application to Single‐Cell Nanoencapsulation

AbstractThe melanoidin from soluble coffee is utilized as a material‐independent, multipurpose coating material. Instantaneous complexation of the coffee melanoidin (CM) with ferric ion (Fe3+) leads to surface‐adhesive aggregates, inducing sequential film deposition. Various chemical groups of the CM also allow for post‐functionalizations of the CM film, including surface‐initiated, ring‐opening polymerization and bioinspired silicification. In addition, the CM‐based coating is applied to single‐cell nanoencapsulation with a strategy of biphasic interfacial reactions. The method is highly cytocompatible (viability &gt;98%), and the CM shell is cytoprotective against lytic enzymes. The coated cells inherit the characterictics of the CM, such as post‐functionalizability and antioxidant property. Considering that surface‐coating technologies with cytocompatible natural polymers have widely been used for engineering bioentities, the CM‐based coating strategy would provide an advanced option for biomedical applications.

Association between biphasic reactions and the systems of symptoms and treatment in patients with anaphylaxis hospitalized from the emergency department.

Anaphylaxis is a severe, life-threatening, generated or systemic reaction, and biphasic reaction could occur in some cases. We investigated the clinical course of anaphylaxis in our hospital and studied the relationship between biphasic reactions and the symptoms and treatments for predicting the onset of biphasic reactions. We retrospectively reviewed the medical records of 120 patients with anaphylaxis who were admitted to our hospital from the emergency department during April 2008-October 2015. The incidence of biphasic reactions of anaphylaxis in our hospital was 10.8% (13 patients) without significant difference when compared with that in previous reports. Regarding the development of biphasic reactions, symptoms, the number of systems of symptoms and severity of the initial reaction, and treatment with adrenaline and corticosteroid were not clearly related with biphasic reaction. Use of adrenaline in the initial treatment was approximately 60%. Of the 13 biphasic reactions, 11 (84.5%) were as equal/mild as the original symptoms. This study could not show the factors predicting the onset of biphasic reactions. Further prospective and nationwide studies are required to research biphasic reactions.

Speeding up biphasic reactions with surface nanodroplets.

Biphasic chemical reactions compartmentalized in small droplets offer advantages, such as streamlined procedures for chemical analysis, enhanced chemical reaction efficiency and high specificity of conversion. In this work, we experimentally and theoretically investigate the rate for biphasic chemical reactions between acidic nanodroplets on a substrate surface and basic reactants in a surrounding bulk flow. The reaction rate is measured by droplet shrinkage as the product is removed from the droplets by the flow. In our experiments, we determine the dependence of the reaction rate on the flow rate and the solution concentration. The theoretical analysis predicts that the life time τ of the droplets scales with Peclet number Pe and the reactant concentration in the bulk flow cre,bulk as τ∝ Pe-3/2cre,bulk-1, in good agreement with our experimental results. Furthermore, we found that the product from the reaction on an upstream surface can postpone the droplet reaction on a downstream surface, possibly due to the adsorption of interface-active products on the droplets in the downstream. The time of the delay decreases with increasing Pe of the flow and also with increasing reactant concentration in the flow, following the scaling same as that of the reaction rate with these two parameters. Our findings provide insight for the ultimate aim to enhance droplet reactions under flow conditions.

Band gap engineering of lead halide perovskite nanocrystals via room temperature bi-phasic anion exchange reactions

Post-synthetic structural/chemical transformations of lead halide perovskites by anion exchange reaction has been considered as one of the versatile methods for engineering the band gap at the nanoscale. Herein, we discuss the tuning of the band gap of CsPbX3 (X = Cl, Br, I) perovskite nanocrystals by a bi-phasic anion exchange method. This was achieved by the controlled reaction between KCl/KI with CsPbBr3 perovskites at room temperature under an inert atmosphere. The molar equivalents of the reaction precursors, as well as the reaction time play a crucial role in deciding the band gap of perovskites. Treatment of KCl with CsPbBr3 perovskites resulted in the systematic blue shift of the absorption and emission spectrum. In contrast to this, a red shift in the absorption and emission was observed upon treating CsPbBr3 perovskites with KI. Moreover, by adjusting the precursor concentrations, from a single reaction, we can synthesize lead halide perovskites emitting covering the whole visible region. The whole reaction was carried out by a bi-phasic method, where the CsPbBr3 perovskite nanocrystals dispersed in chloroform was allowed to react with KCl/KI in the solid state. By engineering the band gap, suitable perovskite nanocrystals can be obtained for various applications in light harvesting, display devices, and photovoltaics.

Anaphylaxis: Ten-year retrospective study from a tertiary-care hospital in Asia.

The study of anaphylaxis in different geographic areas raises the awareness to improve prevention and medical care. To investigate the incidence, causes, characteristics, and management of anaphylaxis in Chiang Mai, Thailand. We performed a retrospective review, based on ICD-10 electronic medical records of patients who attended the Out-Patient and Emergency Departments at Chiang Mai University Hospital from January 2007 to December 2016. A total of 441 episodes of anaphylaxis in 433 patients were analyzed. Three-hundred and sixty-two (84%) were adults and 71 (16%) were children. Anaphylaxis was common in the second and third decades of life. The incidence rate for all causes of anaphylaxis was 3.9 episodes per 100,000 out-patient and emergency visits per year. The rate in children was more frequent than in adults. Foods were the most common culprit (47%), followed by insect stings (23%) and drugs (18%). Severe anaphylaxis, defined as the loss of consciousness, hypotension, respiratory failure, or cyanosis were found in 163 events (37%). The time lapses between exposure with an allergen and the onset of symptom less than 30 minutes and triggered by insect stings were significantly associated with severe anaphylaxis. Biphasic reactions occurred in 6 patients (1.4%). Adrenaline injections were prescribed in most of patients (90%). There were no fatality cases in the past 10 years. The incidence of anaphylaxis in our hospital appears more often in children than in adults. The frequency in adults trends to be increasing. Food and insect stings are the common causative agents.

Biphasic Reactions in Emergency Department Anaphylaxis Patients: A Prospective Cohort Study

Biphasic reaction rates and potential associated risk factors are not well understood. To evaluate biphasic reaction rates and associated risk factors. We prospectively enrolled patients with anaphylaxis at 2 Midwestern academic emergency departments (EDs). We gathered data using patient and ED provider surveys and a structured health record review. Biphasic reaction rates and clinically significant biphasic reaction rates, defined as recurrent reactions that met anaphylaxis diagnostic criteria or were treated with epinephrine, were calculated. Characteristics associated with biphasic reactions were assessed with logistic regression and reported with odds ratios (ORs) and 95% CIs. Of 430 ED anaphylaxis visits, 31 (7.2%) patients had biphasic reactions; 22 (5.1%) had clinically significant biphasic reactions. The median time from anaphylaxis onset to first epinephrine dose was longer for patients with biphasic (78 minutes) than uniphasic courses (45 minutes) (P= .005). A biphasic course was associated with an ED setting of first epinephrine dose (OR, 3.72; 95% CI, 1.36-10.14) and a delay of more than 30 minutes from symptom onset to first epinephrine dose (OR, 3.39; 95% CI, 1.13-10.18), and was inversely associated with arrival by ambulance (OR, 0.18; 95% CI, 0.05-0.61). A clinically significant biphasic reaction was associated with an ED setting of first epinephrine dose (OR, 3.32; 95% CI, 1.08-10.25) and inversely associated with arrival by ambulance (OR, 0.08; 95% CI, 0.01-0.61). Biphasic reactions and clinically significant biphasic reactions occurred in 7.2% and 5.1% of ED anaphylaxis patients, respectively. Delayed epinephrine administration was associated with biphasic reactions.

Using an Automated Monitoring Platform for Investigations of Biphasic Reactions

Insights and mechanistic studies into biphasic reactions are often challenging due to difficulty in deploying in situ reaction-monitoring or sampling procedures. Herein, we describe the development...