Nonlinear relationship between platelet count and 30-day in-hospital mortality in ICU acute respiratory failure patients: a multicenter retrospective cohort study.

BACKGROUND: Limited evidence exists regarding the link between platelet count and 30-day in-hospital mortality in acute respiratory failure (ARF) patients. Thus, this study aims to investigate this association among ICU patients experiencing acute respiratory failure. METHODS: We conducted a retrospective cohort study across multiple centers, utilizing data from the US eICU-CRD v2.0 database covering 22,262 patients with ARF in the ICU from 2014 to 2015. Our aim was to investigate the correlation between platelet count and 30-day in-hospital mortality using binary logistic regression, subgroup analyses, and smooth curve fitting. RESULTS: The 30-day in-hospital mortality rate was 19.73% (4393 out of 22,262), with a median platelet count of 213 × 109/L. After adjusting for covariates, our analysis revealed an inverse association between platelet count and 30-day in-hospital mortality (OR = 0.99, 95% CI 0.99, 0.99). Subgroup analyses supported the robustness of these findings. Furthermore, a nonlinear relationship was identified between platelet count and 30-day in-hospital mortality, with the inflection point at 120 × 109/L. Below the inflection point, the effect size (OR) was 0.89 (0.87, 0.91), indicating a significant association. However, beyond this point, the relationship was not statistically significant. CONCLUSION: This study establishes a clear negative association between platelet count and 30-day in-hospital mortality among ICU patients with ARF. Furthermore, we have identified a nonlinear relationship with saturation effects, indicating that among ICU patients with acute respiratory failure, the lowest 30-day in-hospital mortality rate occurs when the baseline platelet count is approximately 120 × 109/L.

Tunable Optical Rotation in Twisted Black Phosphorus.

Black phosphorus (BP) is a typical two-dimensional (2D) layered material with strong in-plane anisotropy and large birefringence, making it possible to manipulate the light field with atomically controlled devices for various optoelectronic and photonic applications-for instance, atomic thickness waveplates. The twist angle in twisted black phosphorus (TBP) can be presented as a new tunable dimension to control BP's optical anisotropy. Here, we report a large and tunable optical rotation effect in TBP, the result of regulating the twist angle and BP thickness. To accurately study the optical rotation and the impact of the twist angle, we developed a new method to prepare TBP. A lab-made polarimeter microscope was used to visualize the optical rotation mapping of TBP. A large polarization-plane rotation (PORA) of 0.49° per atomic layer was observed from an air/BP/SiO2/Si Fabry-Pérot cavity at 600 nm, an order of magnitude higher than the PORA of 0.05° per atomic layer reported earlier. For the same thickness, the PORA of TBP can be tuned from 0.48° to 7.75° based on the twist angle from 0° to 90°. Our work provides an efficient method to investigate the anisotropy of 2D materials and their heterojunctions. TBP could help us design novel optical and optoelectronic devices such as tunable nanoscale polarization controllers.

Critical Strain-Induced Photoresponse in Folded Graphene Superlattices.

Strain engineering is the most effective method to break the symmetry of the graphene lattice and achieve graphene band gap tunability. However, a critical strain (>20%) is required to open the graphene band gap, and it is very difficult to achieve such a large strain. This limits the development of experimental research and optoelectronic devices based on graphene strain. In this work, we report a method for preparing large-strain graphene superlattices via surface energy engineering. The maximum strain of the curved lattice could reach 50%. In particular, our pioneering work reports the behavior of an ultrafast (as short as 6 ps) photoresponse in a strained folded graphene superlattice. The photocurrent map shows a large increase (up to 102) of the photoresponsivity in the tensile graphene lattice, which is generated by the interaction between the strained and pristine graphene. Through Raman spectroscopy, Kelvin probe force microscopy, and high-resolution transmission electron microscopy, we demonstrate that the ultrathreshold strain in the graphene bends triggers the opening of the graphene band gap and results in a unique photovoltaic effect. This work deepens the understanding of the strain-induced change of the photoelectrical properties of graphene and proves the potential of strained graphene as a platform for the generation of novel high-speed, miniaturized graphene-based photodetectors.

Layer contribution to optical signals of van der Waals heterostructures.

The optical signals (such as Raman scattering, absorption, reflection) of van der Waals heterostructures (vdWHs) are very important for structural analysis and the application of optoelectronic devices. However, there is still a lack of research on the effect of each layer of two-dimensional materials on the optical signals of vdWHs. Here, we investigated the contribution from different layers to the optical signal of vdWHs by using angle-resolved polarized Raman spectroscopy (ARPRS) and angle-dependent reflection spectroscopy. A suitable theoretical model for the optical signal of vdWHs generated by different layers was developed, and vdWHs stacked by different two-dimensional (2D) materials were analyzed. The results revealed a strong dependence of the relative strengths of the optical signals of the upper and lower layers on the thicknesses of 2D materials and the SiO2 layer on the Si/SiO2 substrate. Interestingly, on the 285 nm SiO2/Si substrate, the contribution to the optical signal by the underlying 2D material was much greater than that by the upper layer. Furthermore, optical signals originating from different layers of twisted black phosphorus (BP) for different twist angles were studied. There is great significance for optical spectroscopy to study vdWHs, as well as the development of better twisted 2D materials and moiré physics.

Photoresponse in a Strain-Induced Graphene Wrinkle Superlattice.

Applied strain introduces significant changes in the carbon-carbon bond of graphene and thereby forms electronic superlattices. The electron/phonon coupling and existence of pseudogauge fields within these superlattices render unique electronic and magnetism properties. However, the interfacial interactions between strained and pristine graphene have rarely been studied. Herein, we report a prominent increase in photocurrent at the interface between pristine graphene and the strain-induced superlattice (i.e., the graphene wrinkle). The photocurrent distribution indicates a large increase in the bending lattice of graphene. These results demonstrate that the photocurrent enhancement is due to the difference in the Seebeck coefficient between pristine graphene and deformed superlattices, resulting in a significant increase in the photothermoelectric effect at the interface.

(E)-N'-[(2-Hydroxynaphthalen-1-yl)methylidene]nicotinohydrazide.

In the mol-ecule of the title compound, C(17)H(13)N(3)O(2), the naphthyl ring system and the pyridine ring form a dihedral angle of 12.2 (3)°. An intra-molecular O-H⋯N hydrogen bond generates a six-membered ring with an S(6) ring motif. This also contributes to the relative overall near planarity of the mol-ecule [r.m.s. deviation of all 22 non-H atoms = 0.107 (5) Å]. In the crystal, mol-ecules are linked through inter-molecular N-H⋯N hydrogen bonds, forming chains along the a axis.