Continuous addition kinetic elucidation: catalyst and reactant order, rate constant, and poisoning from a single experiment.

Kinetic analysis of catalytic reactions is a powerful tool for mechanistic elucidation but is often challenging to perform, limiting understanding and therefore development of these reactions. Establishing order in a catalyst is usually achieved by running several reactions at different loadings, which is both time-consuming and complicated by the challenge of maintaining consistent run-to-run experimental conditions. Continuous addition kinetic elucidation (CAKE) was developed to circumvent these issues by continuously injecting a catalyst into a reaction, while monitoring reaction progress over time. For reactions that are mth order in a single yield-limiting reactant and nth order in catalyst, a plot of reactant concentration against time has a shape dependent only on the orders m and n. Therefore, fitting experimental CAKE data (using open access code or a convenient web tool) allows the reactant and catalyst orders, rate constant, and the amount of complete catalyst inhibition to be determined from a single experiment. Kinetic information obtained from CAKE experiments showed good agreement with the literature.

Canadian family members' experiences with guilt, judgment and secrecy during medical assistance in dying: a qualitative descriptive study.

BACKGROUND: Although research briefly mentions that family members have encountered unexpected experiences during the medical assistance in dying (MAiD) process, from keeping MAiD a secret, to being judged and feeling guilty, the potential implications of these are less understood. This study's aim was to examine guilt, judgment and secrecy as part of the MAiD experiences of family members in Canada. METHODS: We conducted a qualitative descriptive study with 1-hour semistructured interviews by telephone or video from December 2020 to December 2021. Through local and national organizations, we recruited Canadian family members with MAiD experience. A subset analysis of unexpected experiences was conducted, which identified 3 categories: guilt, judgment and secrecy. Similar codes were grouped together within each category into themes. Participants were sent the draft manuscript and their suggestions were integrated. RESULTS: A total of 45 family members from 6 provinces who experienced MAiD from 2016 to 2021 participated. Many people who had MAiD were diagnosed with cancer, comorbidities or neurologic disease. Some participants unexpectedly found themselves managing guilt, judgment and/or secrecy, which may complicate their grieving and bereavement. Numerous participants experienced judgment from relatives, friends, religious people and/or health care professionals. Many kept MAiD secret because they were not allowed to tell or for religious reasons, and/or selectively told others. INTERPRETATION: Family members said they were ill-prepared to manage their experiences of guilt, judgment and secrecy during the MAiD process. MAiD programs and assessors/providers could provide family-specific information to help lessen these burdens and better prepare relatives for common, yet unexpected, experiences they may encounter.

Coupling Perovskite Quantum Dot Pairs in Solution using a Nanoplasmonic Assembly.

Perovskite quantum dots (PQDs) provide a robust solution-based approach to efficient solar cells, bright light emitting devices, and quantum sources of light. Quantifying heterogeneity and understanding coupling between dots is critical for these applications. We use double-nanohole optical trapping to size individual dots and correlate to emission energy shifts from quantum confinement. We were able to assemble a second dot in the trap, which allows us to observe the coupling between dots. We observe a systematic red-shift of 1.1 ± 0.6 meV in the emission wavelength. Theoretical analysis shows that the observed shift is consistent with resonant energy transfer and is unusually large due to moderate-to-large quantum confinement in PQDs. This demonstrates the promise of PQDs for entanglement in quantum information applications. This work enables future in situ control of PQD growth as well as studies of the coupling between small PQD assemblies with quantum information applications in mind.

Tuning the dielectric response in a nanocomposite material through nanoparticle morphology.

Ceramic materials such as metal oxides, mixed metal oxides and silicates, constitute a broadly-used, high-performance technology for electronic insulators. The introduction of metal cluster dopants and molecular-scale inclusions in a dielectric matrix provides an opportunity for manufacturing new high-κ solid-state dielectrics with tunable field-response properties. The quantum properties of these metallic nanoparticles depend strongly on their size and shape, a characteristic that can be exploited in changing the response properties of a material, whereas the small nanoparticle size can help limit the issues of conduction and current leakage. Here, we model the polarization of molecular-scale silver inclusions in a magnesium oxide matrix, using the Modern Theory of Polarization and Car-Parrinello Molecular Dynamics (CPMD). Details of the implementation are laid out, including handling of current jumps due to the distortion of the matrix during the simulation. Several trends in the dielectric response are considered in this work, including the effects of nanoparticle size, shape and orientation relative to the applied field. Dielectric permittivity enhancements of 30-100% are observed with inclusion sizes varying from 8 to 32 atoms, considering both rod-like and disk-like inclusions, with alignment either parallel or perpendicular to the external field.

Intramuscular dirofilariasis mimicking an orbital metastasis in a patient with breast cancer.

We present the unusual case of a 74 year-old female with a history of breast cancer who presented with acute painless orbital swelling and vertical diplopia. MRI revealed a focal enhancing mass within the superior rectus muscle. As the concern for metastatic disease was high, surgical biopsy was performed and revealed an unusual mimicker of metastatic disease, the parasitic infection dirofilariasis.

A new heat source for thermochemical ablation based on redox chemistry: initial studies using permanganate.

PURPOSE: To evaluate exothermic permanganate redox chemistry for utility in tumour ablation. MATERIALS AND METHODS: Sodium permanganate (1-3 mL, 1 or 2 M) and glycerol (1 mL, 1 M) were injected in triplicate into a beaker using three injection orders: (1) simultaneous, (2) glycerol injection then permanganate injection, (3) permanganate injection then glycerol injection. Selected experiments were repeated with glucose, sucrose, dextrin, maltodextrin, different polysaccharides, and polyvinyl alcohol as substrates. Simultaneous injections of permanganate (0.5 and 1 mL, 2 M) and glucose (1 mL, 1 M) into explanted porcine muscle were also performed. Temperatures were recorded with a thermocouple probe or an infrared camera. RESULTS: With optimal conditions of 2 M permanganate and 1 M glycerol at 1 mL each, an average maximum temperature of 97.4 degrees C was obtained for all three injection orders. When glucose and sucrose were used as the substrates, similar temperatures were achieved but at different rates. Dextrin and maltodextrin (180 g/L) led to maximum temperatures of 42.5 degrees and 51.1 degrees C respectively when simultaneously injected with permanganate (1 mL, 2 M). Polysaccharides and polyvinyl alcohols under the same conditions resulted in a minimal temperature increase. Intramuscular injections of glucose (0.5 mL, 1 M) and permanganate (0.5 mL, 2 M) reached an average temperature of 76.5 degrees C at the lesion site. CONCLUSIONS: The permanganate redox reaction is a powerful system with potential to reach tumouricidal temperatures. The reagent volumes, concentrations, injection order, and substrate choice allow a measure of control over the reaction.