How Reproducible is the Synthesis of Zr-Porphyrin Metal-Organic Frameworks? An Interlaboratory Study.

Metal-organic frameworks (MOFs) are a rapidly growing class of materials that offer great promise in various applications. However, the synthesis remains challenging: for example, a range of crystal structures can often be accessed from the same building blocks, which complicates the phase selectivity. Likewise, the high sensitivity to slight changes in synthesis conditions may cause reproducibility issues. This is crucial, as it hampers the research and commercialization of affected MOFs. Here, it presents the first-ever interlaboratory study of the synthetic reproducibility of two Zr-porphyrin MOFs, PCN-222 and PCN-224, to investigate the scope of this problem. For PCN-222, only one sample out of ten was phase pure and of the correct symmetry, while for PCN-224, three are phase pure, although none of these show the spatial linker order characteristic of PCN-224. Instead, these samples resemble dPCN-224 (disordered PCN-224), which has recently been reported. The variability in thermal behavior, defect content, and surface area of the synthesised samples are also studied. The results have important ramifications for field of metal-organic frameworks and their crystallization, by highlighting the synthetic challenges associated with a multi-variable synthesis space and flat energy landscapes characteristic of MOFs.

Smell disorders evolution after chronic rhinosinusitis with polyps surgery

: The effects of chronic rhino sinusitis with polyps (CRSWP) surgery on smell symptoms have not been sufficiently studied. The aim of this study was to evaluate the impact of CRSWP surgery on smell symptoms over short and long-term follow-up and to identify the factors that might influence their evolution. Patients and methods: This was a retrospective study about 184 patients operated endoscopically for CRSWP. In post operative period, long-term local steroids were prescribed systematically. The sense of smell was evaluated preand post-operatively according to a subjective score (1: good smell, 2: hyposmia, 3: anosmia). Some factors, related to the patient, the CRSWP and the treatment, were tested in order to identify predictors of smell outcome after surgery.. Results: Before surgery, the anosmia and the hyposmia were noted in 90.8% and in 8.7% of cases, respectively. At six months after surgery, the improvement of olfactory score was significant: 84% of patient had the score 1 compared with 0.5% preoperatively (p < 0.0001). This improvement was maintained during the 2 first years and decreased significantly at 3 years, although an average delay of polyps recurrence was 23.4 months. Among the factors studied in our series, only the observance of postoperative corticosteroids was retained as a predictor of smell recovery after surgery (p = 0,011). Conclusion: CRSWP surgery can significantly improve the smell sense, especially during the two first years. This effect can be sustainable if good post operative compliance for local corticosteroid are achieved

Polariton response in the presence of Brownian dissipation from molecular vibrations.

We study the elastic response of a stationarily driven system of a cavity field strongly coupled with molecular excitons, taking into account the main dissipation channels due to the finite cavity linewidth and molecular vibrations. We show that the frequently used coupled oscillator model fails in describing this response especially due to the non-Lorentzian dissipation of the molecules to their vibrations. Signatures of this failure are the temperature dependent minimum point of the polariton peak splitting, the uneven polariton peak height at the minimum splitting, and the asymmetric shape of the polariton peaks even at the experimentally accessed "zero-detuning" point. Using a rather generic yet representative model of molecular vibrations, we predict the polariton response in various conditions, depending on the temperature, molecular Stokes shift and vibration frequencies, and the size of the Rabi splitting. Our results can be used as a sanity check of the experiments trying to "prove" results originating from strong coupling, such as vacuum-enhanced chemical reaction rate.