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Background: Cardiac troponins are highly sensitive and specific biomarkers for cardiac injury. Previous studies evaluating the effect of positive airway pressure (PAP) on cardiac troponins in patients with sleep‐disordered breathing (SDB) have yielded conflicting results. The meta‐analysis was performed to examine the effect of PAP on cardiac troponins in SDB patients. Methods: PubMed, Web of Science, and EMBASE before September 2021 on original English language studies were searched. The data on cardiac troponins in both baseline and post‐PAP treatment were extracted from all studies. The data on the change of cardiac troponins in both PAP and control group were extracted from randomized controlled trials. Standardized mean difference (SMD) was used to synthesize quantitative results. Results: A total of 11 studies were included. PAP treatment was not associated with a significant change in cardiac troponin T between the baseline and post‐PAP treatment (SMD = −0.163, 95% confidence interval [CI] = −0.652 to 0.326, z = 0.65, p =.514). The pooled estimate of SMD of cardiac troponin I between the pre‐ and post‐PAP treatment was 0.287, and the 95% CI was −0.586 to 1.160 (z = 0.64, p =.519). The pooled SMD of change of cardiac troponin T between the PAP group and control group was −0.473 (95% CI = −1.198 to 0.252, z = 1.28, p =.201). Conclusions: This meta‐analysis revealed that PAP treatment was not associated with any change of cardiac troponin in SDB patients. [ABSTRACT FROM AUTHOR]

Multi‐functionalized lead‐free organic‐inorganic hybrid ferroelectrics have recently realized diverse applications especially for optoelectronics and photovoltaics. Herein, the chiral Zn‐based organic−inorganic hybrids are discovered: [(R)‐(−)‐2‐methylpiperazine‐1,4‐diium][Zn(H2O)6]•(SO4)2 (RMPZnS2, space group P21) and [(S)‐(+)‐2‐methylpiperazine‐1,4‐diium]2[Zn(H2O)6]•(SO4)3 (SMP2ZnS3, space group P21212). Through experimental and computational investigations, it is found that RMPZnS2 is a ferroelectric with considerable large polarization value (P ≈ 9.5 µC cm−2) along b–axis, and its ferroelectric‐paraelectric phase transition is switched by rotation of organic cations. Meanwhile, it also possesses a fascinating photovoltaic effect driven by the polar charges at solar‐blind UV region, endowing it with the potential of self‐driven photodetection. In addition, white‐light emissions of the RMPZnS2 and SMP2ZnS3 are observed. The enhanced luminescence by heating is especially suitable for the application in white light‐emitting diodes. Overall, these chiral emission ferroelectrics at the supramolecular level will largely expand their applications in multidisciplinary fields. [ABSTRACT FROM AUTHOR]

A new piperidyl‐based molecular ferroelectric piperidine‐4‐ylmethanaminium perchlorate (compound 1) has been successfully synthesized, which undergoes a reversible phase transition around Tc = 258.8 K. The spontaneous polarization of compound 1 is about 0.63 μC/cm2 and coercive field as small as 1.14 kV/cm at 192 K. The variable‐temperature single‐crystal X‐ray diffraction reveals that the space group transforms from a polar space group of P21 at 173 K to a centrosymmetric space group of P212121 at 293 K. Especially, the dielectric anomaly at the phase transition temperature increases more than 4 times, which indicates potential applications in switchable dielectric devices. The molecular ferroelectric piperidine‐4‐ylmethanaminium perchlorate (compound 1) with superior switchable dielectric properties, which can be an underlying candidate for switchable dielectric devices. The spontaneous polarization of compound 1 is about 0.63 μC/cm2 and coercive field as small as 1.14 kV/cm at 192 K. The variable‐temperature single‐crystal X‐ray diffraction reveals that the space group transforms from a polar space group of P21 at 173 K to a centrosymmetric space group of P212121 at 293 K. [ABSTRACT FROM AUTHOR]

In the title compound, C(8)H(9)N(+)·H(2)PO(4) (-), both the cation and anion have crystallographically imposed mirror symmetry (all atoms apart from one O atom lie on the mirror plane). In the crystal, anions and cations are linked by O-H⋯O and π-π stacking inter-actions [centroid-centroid distance = 3.4574 (6) Å], forming chains parallel to the b axis. Adjacent chains are further connected by N-H⋯O hydrogen bonds into a two-dimensional network.

In the title compound, (C(5)H(7)N(2))(2)[ZnCl(4)], the pyridine N atoms are protonated and the [ZnCl(4)](2-) anions adopt a slightly distorted tetra-hedral configuration. In the crystal, weak N-H⋯Cl hydrogen bonds link the mol-ecules into layers, while weak π-π inter-actions [centroid-centroid distance = 4.2758 (18) Å] also help to stabilize the packing.

In the title compound, [Zn(C(11)H(8)N(5)O)(N(3))](n), the Zn atom is hexa-coordinated by five N atoms and one O atom in a distorted octa-hedral geometry. The chelating 5-(8-quinolyloxymeth-yl)tetra-zolate ligands are approximately planar, with a dihedral angle of 3.6 (2)° between the quinoline and tetra-zole planes. Adjacent Zn atoms are linked by two bridging azide ligands across a centre of inversion, and further coordination by one N atom of an adjacent tetra-zole unit forms two-dimensional frameworks in (100). C-H⋯N inter-actions exist between ligands in neighbouring layers.