Au9 nanocluster adsorption and agglomeration control through sulfur modification of mesoporous TiO2.

In the present work phenyl phosphine-protected Au9 nanoclusters were deposited onto (3-mercaptopropyl) trimethoxysilane (MPTMS) modified and unmodified mesoporous screen printed TiO2. The removal of the cluster ligands by annealing was applied to enhance the interaction between Au cluster cores and semiconductor surfaces in the creation of efficient photocatalytic systems. The heat treatment could lead to undesired agglomeration of Au clusters, affecting their unique properties as size specific clusters. To address this challenge, the semiconductor surfaces were modified by MPTMS. Characterization techniques confirm the effectiveness of the modification processes, and XPS demonstrates that S functionalized MTiO2 is more efficient than MTiO2 in increasing Au9 NCs adsorption by a factor of 10 and preventing Au cluster agglomeration even after annealing. Overall, this work contributes valuable insights into photocatalytic systems through controlled modification of semiconductor surfaces and Au nanocluster deposition.

Implementing the IMIST-AMBO tool for paramedic to trauma team handovers: a video review analysis.

OBJECTIVE: Patient handover between paramedics and the trauma team is vulnerable to communication errors that may adversely affect patient care. This study assesses the feasibility of a handover tool, IMIST-AMBO (acronym of categories), implementation in the trauma bay and evaluates the degree to which it improves handover metrics. METHODS: This is a prospective observational cohort study conducted at Canada's largest level-one trauma center. Feasibility of the tool implementation and improvement in handover metrics were assessed. Strategies for implementation included distribution of an educational video and posters, and point-of-care reminders in the trauma bay. Two reviewers independently assessed video recordings of handovers to evaluate handover metrics. Findings were compared to data obtained during a knowledge gap analysis conducted prior to the initiation of this study at the same institution. RESULTS: Over 13 weeks (August to November 2020), 140 videos were recorded, of which 80 used the IMIST-AMBO tool (compliance of 57%). Paramedic adherence to the handover structure occurred in 70.4% of cases, with greater adherence to the IMIST (82.2%) compared to the AMBO (47.1%) section. The mean (± standard deviation) handover duration was shorter (1 min:58 s ± 0:44 s during implementation vs. 2 min:47 s ± 1:14 s pre-implementation, [p < 0.001]). Frequency of parallel conversations and informal handovers improved (61% to 30% and 65% to 13%, [p < 0.001], respectively). Interruptions during the handover decreased from 3.05 (± 1.95) to 1.5 (± 1.7), p < 0.001. The tool was received favorably among study participants. CONCLUSION: The IMIST-AMBO tool reduced the frequency of interruptions, parallel conversations, and informal handovers during paramedic-trauma team handovers at our institution. The quality and amount of information communicated per handover improved, all with a decrease in handover duration. The IMIST-AMBO tool may be applied to other trauma centers across Canada, or more broadly on an international scale.

RéSUMé: OBJECTIFS: Le transfert des patients entre les ambulanciers paramédicaux et l'équipe de traumatologie est vulnérable aux erreurs de communication qui peuvent nuire aux soins aux patients. Cette étude évalue la faisabilité d'un outil de transfert, IMIST-AMBO (acronyme des catégories), mis en œuvre dans le service de traumatologie et évalue dans quelle mesure il améliore les paramètres de transfert. MéTHODES: Il s'agit d'une étude de cohorte observationnelle prospective menée dans le plus grand centre de traumatologie de niveau 1 du Canada. La faisabilité de la mise en œuvre de l'outil et l'amélioration des paramètres de transfert ont été évaluées. Les stratégies de mise en œuvre comprenaient la distribution d'une vidéo et d'affiches éducatives, ainsi que des rappels au point de service dans la salle de traumatologie. Deux examinateurs ont évalué indépendamment les enregistrements vidéo des transferts pour évaluer les paramètres de transfert. Les résultats ont été comparés aux données obtenues lors d'une analyse des lacunes en matière de connaissances réalisée avant le lancement de cette étude dans le même établissement. RéSULTATS: Sur 13 semaines (août à novembre 2020), 140 vidéos ont été enregistrées, dont 80 ont utilisé l'outil IMIST-AMBO (conformité de 57%). L'adhésion des ambulanciers paramédicaux à la structure de transfert s'est produite dans 70.4% des cas, avec une plus grande adhésion à l'IMIST (82.2%) que l'AMBO (47,1%). La durée moyenne (± écart-type) du transfert était plus courte (1 min: 58 s ± 0: 44 s pendant la mise en œuvre contre 2 min: 47 s ± 1: 14 s avant la mise en œuvre, p < 0.001). La fréquence des conversations parallèles et des transferts informels s'est améliorée (de 61% à 30% et de 65% à 13%, [p < 0.001], respectivement). Les interruptions pendant le transfert ont diminué de 3.05 (± 1.95) à 1.5 (± 1.7), p < 0.001. L'outil a été accueilli favorablement par les participants à l'étude. CONCLUSION: L'outil IMIST-AMBO a réduit la fréquence des interruptions, des conversations parallèles et des transferts informels pendant les transferts de l'équipe paramédicale de traumatologie dans notre établissement. La qualité et la quantité d'informations communiquées par transfert se sont améliorées, tout en réduisant la durée du transfert. L'outil IMIST-AMBO peut être appliqué à d'autres centres de traumatologie à travers le Canada, ou plus largement à l'échelle internationale.

Impurity profiling of methamphetamine synthesized from methyl α-acetylphenylacetate.

The group of P2P precursors including α-phenylacetoacetonitrile (APAAN), α-phenylacetoamide (APAA) and methyl α-acetylphenylacetate (MAPA) has become increasingly popular in Europe and other parts of the world in the last decade. Previous investigations have reported the use of APAAN in the synthesis of amphetamine and methamphetamine and identified a range of characteristic impurities. This research has expanded upon the current literature by investigating the use of MAPA in the synthesis of methamphetamine. In this study methamphetamine was synthesized via three common clandestine methods: the Leuckart synthesis and two reductive amination methods. We report the identification of seven impurities, four of which are methyl ester equivalents of impurities previously reported for the detection of APAAN. These are methyl 2-phenylbut-2-enoate, methyl 2-phenyl-3-hydroxybutanoate, methyl 3-(methylamino)-2-phenylbut-2-enoate and methyl 3-(methylamino)-2-phenylbutanoate. The other impurities identified are ethyl ester compounds formed via transesterification of the methyl ester due to the reaction solvent. This susceptibility for transesterification suggests that identification of the pre-precursor used may not always be straightforward and may be dependent on the reaction conditions employed. Of the impurities reported, methyl 3-(methylamino)-2-phenylbutanoate was deemed to be a potentially reliable impurity for detection of the use of MAPA; however, it is expected that lower levels of characteristic impurities may be detected in methamphetamine synthesized from MAPA than that from APAAN.

Impurity profiling of methamphetamine synthesised from α-phenylacetoacetonitrile (APAAN).

The rise in popularity of 'designer' precursor compounds for the synthesis of amphetamine-type stimulants poses a significant challenge to law enforcement agencies. One such precursor is α-phenylacetoacetonitrile (APAAN). APAAN emerged in Europe in 2010 and quickly became one of the most popular precursors for amphetamine synthesis in that region. Previous literature has identified four APAAN-specific impurities formed in the synthesis of amphetamine; however, there is currently no research on the use of APAAN in the synthesis of methamphetamine, which is more likely to be employed in a non-European market. In this study methamphetamine was synthesised via three common clandestine methods: the Leuckart method and two reductive amination methods. We report the identification of five new impurities and two previously identified impurities characteristic for the use of APAAN in the synthesis of methamphetamine. The newly identified impurities were characterised by MS and NMR and determined to be (E)-3-(methylamino)-2-phenylbut-2-enenitrile, 3-(methylamino)-2-phenylbutanenitrile, 3-methyl-2,4-diphenylpentanedinitrile, 2-phenylbutyronitrile and 3-hydroxy-2-phenylbutanenitrile.

EVM Loss: A Loss Function for Training Neural Networks in Communication Systems.

Neural networks and their application in communication systems are receiving growing attention from both academia and industry. The authors note that there is a disconnect between the typical objective functions of these neural networks with regards to the context in which the neural network will eventually be deployed and evaluated. To this end, a new loss function is proposed and shown to increase the performance of neural networks when implemented in a communication system compared to previous methods. It is further shown that a 'split complex' approach used by many implementations can be improved via formalisation of the 'concatenated complex' approach described herein. Experimental results using the orthogonal frequency division multiplexing (OFDM) and spectrally efficient frequency division multiplexing (SEFDM) modulation formats with varying bandwidth compression factors over a wireless visible light communication (VLC) link validate the efficacy of the proposed method in a real system, achieving the lowest error vector magnitude (EVM), and thus bit error rate (BER), across all experiments, with a 5 dB to 10 dB improvement in the received symbols EVM overall compared to the baseline implementation, with bandwidth compressions down to 40% compared to OFDM, resulting in a spectral efficiency gain of 67%.

A Tetra-Porphyrin Host Exhibiting Interannular Cooperativity.

Recently identified as another form of cooperativity, interannular cooperativity is rarely observed in supramolecular chemistry. A tetra-porphyrin molecular tweezer with two bis-porphyrin binding sites is reported that exhibits archetypal interannular cooperativity when complexing 1,4-diazabicyclo[2.2.2]octane (DABCO). The UV/Vis titration data best supported a 1:2 plus 2:2 plus 1:4 complexation model (host:guest), giving K12 =6.32×1013  m-2 , K22 =3.04×1020  m-3 , and K14 =1.92×1016  m-4 in CHCl3 . The NMR titration data supported the formation of two sandwich species, including tetra-porphyrin⋅(DABCO)2 as the major species, although there are speciation differences between UV/Vis and NMR concentrations. Using statistical analysis, interannular cooperativity (γ) for tetra-porphyrin⋅(DABCO)2 was determined to be negative (γ=2.41×10-3 ), which may be explained by DABCO being too small to be optimally bound simultaneously at both bis-porphyrin binding sites.

Ranking Oxidant Sensitiveness: A Guide for Synthetic Utility.

Common oxidants used in chemical synthesis, including newly developed perruthenates, were evaluated in the context of understanding (and better appreciating) the sensitiveness and associated potential hazards of these reagents. Analysis using sealed cell differential scanning calorimetry (scDSC) facilitated Yoshida correlations, which were compared to impact sensitiveness and electrostatic discharge experiments (ESD), that enabled sensitiveness ranking. Methyltriphenylphoshonium perruthenate (MTP3, 8), isoamyltriphenylphosphonium perruthenate (ATP3, 7) and tetraphenylphosphonium perruthenate (TP3, 9) were found to be the most sensitive followed by 2-iodoxybenzoic acid (IBX, 2) and benzoyl peroxide (BPO, 10), whereas the most benign were observed to be Oxone (12), manganese dioxide (MnO2 , 13), and N-bromosuccinimide (NBS, 17).

Molecular tweezers with a rotationally restricted linker and freely rotating porphyrin moieties.

The effect of the degree of conformational rigidity and/or flexibility on preorganisation in artificial molecular receptors continues to be actively explored by supramolecular chemists. This work describes a bis-porphyrin architecture, linked via a rigid polycyclic backbone, in which a sterically bulky 2,3,5,6-tetramethylphenyl diimide core restricts rotation to afford two non-interconvertible tweezer conformations; syn- and anti-. After separation, the host-guest chemistry of each conformation was studied independently. The difference in host geometry allows only the syn-conformation to form a strong 1 : 1 bis-porphyrin complex with the diamino ligand 1,4-diazabicyclo[2.2.2]octane (DABCO) (K11 = 1.25 × 108 M-1), with the anti-conformation adopting a 2 : 2 sandwich complex with DABCO (K22 = 5.57 × 1017 M-3).

Detailed investigations into the Akabori-Momotani reaction for the synthesis of amphetamine type stimulants: Part 2.

The Akabori-Momotani reaction can be used to synthesise pseudoephedrine in 50% yield from N-methylalanine and benzaldehyde. This paper investigates electronic effects of substituted benzaldehydes on the reaction to synthesise amphetamine type stimulants and identifies several new Akabori-Momotani by-products, 1-[(4-methoxybenzyl)(methyl)amino]ethanol (11c), 2-(4-methoxyphenyl)-3,4-dimethyl-1,3-oxazolidine (12c), 1,2,3,4-tetramethyl-5,6-di-(4-methoxyphenyl)piperazine (13c) and 1,2,4,5-tetramethyl-3,6-di-(4-methoxyphenyl)piperazine (14c). This paper also investigates pseudoephedrine and methamphetamine isomeric distribution from the Akabori-Momotani reaction with the aid of molecular modelling to understand why more pseudoephedrine than ephedrine is produced.

Polysulfides made from re-purposed waste are sustainable materials for removing iron from water.

Water contaminated with Fe3+ is undesirable because it can result in discoloured plumbing fixtures, clogging, and a poor taste and aesthetic profile for drinking water. At high levels, Fe3+ can also promote the growth of unwanted bacteria, so environmental agencies and water authorities typically regulate the amount of Fe3+ in municipal water and wastewater. Here, polysulfide sorbents-prepared from elemental sulfur and unsaturated cooking oils-are used to remove Fe3+ contaminants from water. The sorbent is low-cost and sustainable, as it can be prepared entirely from waste. The preparation of this material using microwave heating and its application in iron capture are two important advances in the growing field of sulfur polymers.

An investigation into artefacts formed during gas chromatography/mass spectrometry analysis of firearms propellant that contains diphenylamine as the stabiliser.

In the course of providing assistance to legal counsel in a matter that involved the analysis of firearms propellant by gas chromatography/mass spectrometry it was noticed that phenoxazine was reported as a component of 0.22 calibre propellant that contained diphenylamine as the stabiliser. The research was conducted to find how phenoxazine was formed. The results showed that the compound was not phenoxazine but a diphenylamine derivative 4-(phenylimino) cyclohexa-2,5-dien-1-one that formed in the injection port of the gas chromatograph. In addition a second artefact was found to form in the ion source of the mass spectrometer. While the presence of the artefacts does not affect the ability to identify particles as propellant they may impact on comparison with source ammunition.

Insights into the complexation of N-Allyl-4-(4-(N-phenylureido)benzylamino)-1,8-naphthalimide with various anions.

A new urea functionalised 4-amino-1,8-naphthalimide based fluorescent anion sensor was synthesised in 64% yield over three steps. Fluorescence and 1H NMR titrations showed that the sensor complexes strongly with acetate and dihydrogen phosphate and to a lesser extent bromide. The corresponding binding stoichiometries were examined using 1H NMR titrations. Results show that the sensor molecule initially forms 1:1 complexes through hydrogen bonding to the urea moiety, followed by secondary complexation to form higher order host:guest stoichiometries. Specifically, oxyanions complex to the sensor via hydrogen bonding through synergistic aryl C-H and N-H anion interactions in a 1:2 sensor:oxyanion arrangement. Furthermore, 2:1 sensor:oxyanion complexes are formed through an oxyanion linkage between two urea functionalities on different host molecules. This contrasts the majority of previous reports for similar hosts, which indicate 1:1 binding stoichiometry.

Double Sequential External Defibrillation and Survival from Out-of-Hospital Cardiac Arrest: A Case Report.

BACKGROUND: Patients who present in ventricular fibrillation are typically treated with cardiopulmonary resuscitation (CPR), epinephrine, antiarrhythmic medications, and defibrillation. Although these therapies have shown to be effective, some patients remain in a shockable rhythm. Double sequential external defibrillation has been described as a viable option for patients in refractory ventricular fibrillation. OBJECTIVE: To describe the innovative use of two defibrillators used to deliver double sequential external defibrillation by paramedics in a case of refractory ventricular fibrillation resulting in prehospital return of spontaneous circulation and survival to hospital discharge with good neurologic function. CASE: A 28-year-old female sustained a witnessed out-of-hospital cardiac arrest (OHCA). Bystander CPR was performed by her husband followed by paramedics providing high-quality CPR, antiarrhythmic medication, and 6 biphasic defibrillations using standard energy levels. Double sequential external defibrillation was applied and a return of spontaneous circulation was attained on scene and maintained through to arrival to the emergency department. Following admission to hospital the patient was diagnosed with long QT syndrome. An implantable cardioverter defibrillator was placed and the patient was discharged with a Cerebral Performance Category of 2 as well as a modified Rankin Scale of 2 after an 18-day hospital stay. The patient's functional status continued to improve post discharge. CONCLUSION: The addition of double sequential external defibrillation as part of a well-organized resuscitation effort may be a valid treatment option for OHCA patients who present in refractory ventricular fibrillation.

The synthesis and investigation of impurities found in Clandestine Laboratories: Baeyer-Villiger Route Part I; Synthesis of P2P from benzaldehyde and methyl ethyl ketone.

The synthesis of impurities detected in clandestinely manufactured Amphetamine Type Stimulants (ATS) has emerged as more desirable than simple "fingerprint" profiling. We have been investigating the impurities formed when phenyl-2-propanone (P2P) 5, a key ATS precursor, is synthesised in three steps; an aldol condensation of benzaldehyde and methyl ethyl ketone (MEK); a Baeyer-Villiger reaction; and ester hydrolysis. We have identified and selectively synthesised several impurities that may be used as route specific markers for this series of synthetic steps. Specifically these impurities are 3-methyl-4-phenyl-3-buten-2-one 3, 2-methyl-1,5-diphenylpenta-1,4-diene-3-one 9, 2-(methylamino)-3-methyl-4-phenyl-3-butene 16, 2-(Methylamino)-3-methyl-4-phenylbutane 17, and 1-(methylamino)-2-methyl-1,5-diphenylpenta-4-ene-3-one 22.

Mass spectrometry imaging reveals new biological roles for choline esters and Tyrian purple precursors in muricid molluscs.

Despite significant advances in chemical ecology, the biodistribution, temporal changes and ecological function of most marine secondary metabolites remain unknown. One such example is the association between choline esters and Tyrian purple precursors in muricid molluscs. Mass spectrometry imaging (MSI) on nano-structured surfaces has emerged as a sophisticated platform for spatial analysis of low molecular mass metabolites in heterogeneous tissues, ideal for low abundant secondary metabolites. Here we applied desorption-ionisation on porous silicon (DIOS) to examine in situ changes in biodistribution over the reproductive cycle. DIOS-MSI showed muscle-relaxing choline ester murexine to co-localise with tyrindoxyl sulfate in the biosynthetic hypobranchial glands. But during egg-laying, murexine was transferred to the capsule gland, and then to the egg capsules, where chemical ripening resulted in Tyrian purple formation. Murexine was found to tranquilise the larvae and may relax the reproductive tract. This study shows that DIOS-MSI is a powerful tool that can provide new insights into marine chemo-ecology.

SERS and NMR Studies of Typical Aggregation-Induced Emission Molecules.

Over recent decades, aggregation-induced emission (AIE) molecules have attracted increasing attention. Restriction of intramolecular rotation (RIR) has been widely accepted as the cause of the emission when AIE molecules aggregate into clusters. The intramolecular rotation of AIE molecules can be monitored by molecular vibration spectra such as nuclear magnetic resonance (NMR), infrared, and Raman, especially surface-enhanced Raman scattering (SERS) which has high sensitivity down to a single molecule. We employed SERS and NMR to study the AIE emission mechanism and compared experimental results with simulation data to monitor the RIR. Interestingly, we found that intramolecular rotation was also restricted for individual AIE molecules loaded onto SERS substrate surfaces due to the laid-down configuration.

Mechanistic insights into the luminescent sensing of organophosphorus chemical warfare agents and simulants using trivalent lanthanide complexes.

Organophosphorus chemical warfare agents (OP CWAs) are potent acetylcholinesterase inhibitors that can cause incapacitation and death within minutes of exposure, and furthermore are largely undetectable by the human senses. Fast, efficient, sensitive and selective detection of these compounds is therefore critical to minimise exposure. Traditional molecular-based sensing approaches have exploited the chemical reactivity of the OP CWAs, whereas more recently supramolecular-based approaches using non-covalent interactions have gained momentum. This is due, in part, to the potential development of sensors with second-generation properties, such as reversibility and multifunction capabilities. Supramolecular sensors also offer opportunities for incorporation of metal ions allowing for the exploitation of their unique properties. In particular, trivalent lanthanide ions are being increasingly used in the OP CWA sensing event and their use in supramolecular sensors is discussed in this Minireview. We focus on the fundamental interactions of simple lanthanide systems with OP CWAs and simulants, along with the development of more elaborate and complex systems including those containing nanotubes, polymers and gold nanoparticles. Whilst literature investigations into lanthanide-based OP CWA detection systems are relatively scarce, their unique and versatile properties provide a promising platform for the development of more efficient and complex sensing systems into the future.

Morphine glucuronidation and glucosidation represent complementary metabolic pathways that are both catalyzed by UDP-glucuronosyltransferase 2B7: kinetic, inhibition, and molecular modeling studies.

Morphine 3-ß-D-glucuronide (M3G) and morphine 6-ß-D-glucuronide (M6G) are the major metabolites of morphine in humans. More recently, morphine-3-ß-d-glucoside (M-3-glucoside) was identified in the urine of patients treated with morphine. Kinetic and inhibition studies using human liver microsomes (HLM) and recombinant UGTs as enzyme sources along with molecular modeling were used here to characterize the relationship between morphine glucuronidation and glucosidation. The M3G to M6G intrinsic clearance (C(Lint)) ratio (∼5.5) from HLM supplemented with UDP-glucuronic acid (UDP-GlcUA) alone was consistent with the relative formation of these metabolites in humans. The mean C(Lint) values observed for M-3-glucoside by incubations of HLM with UDP-glucose (UDP-Glc) as cofactor were approximately twice those for M6G formation. However, although the M3G-to-M6G C(Lint) ratio remained close to 5.5 when human liver microsomal kinetic studies were performed in the presence of a 1:1 mixture of cofactors, the mean C(Lint) value for M-3-glucoside formation was less than that of M6G. Studies with UGT enzyme-selective inhibitors and recombinant UGT enzymes, along with effects of BSA on morphine glycosidation kinetics, were consistent with a major role of UGT2B7 in both morphine glucuronidation and glucosidation. Molecular modeling identified key amino acids involved in the binding of UDP-GlcUA and UDP-Glc to UGT2B7. Mutagenesis of these residues abolished morphine glucuronidation and glucosidation. Overall, the data indicate that morphine glucuronidation and glucosidation occur as complementary metabolic pathways catalyzed by a common enzyme (UGT2B7). Glucuronidation is the dominant metabolic pathway because the binding affinity of UDP-GlcUA to UGT2B7 is higher than that of UDP-Glc.

VX and VG chemical warfare agents bidentate complexation with lanthanide ions.

Investigations into V-agent interaction with 1,10-phenanthroline nitrate Ln(III) complexes (Eu and Tb) were carried out using luminescence and UV-Vis spectroscopy. Addition of several equivalents of agent resulted in the loss of luminescence intensity and the observation of free 1,10-phenanthroline by UV-Vis. We propose a displacement mechanism in which the V-agent acts as a bidentate ligand to the lanthanide ion. Association constants were determined by luminescence titrations and found to be 10(5) mol(-1) dm(3).