Flexible Photonic Crystal Material for Multiple Anticounterfeiting Applications

In this study, a nanoimprinting method was introduced to fabricate polycarbonate films with transparent and flexible photonic crystal (FPC) structures. The fabricated flexible polymer films display a full-color grating because of the nanohemispherical structures on the surface. Through the Bragg diffraction formula, it was confirmed that the FPC polymer films transfer a part of the light energy to the second-order diffraction spectrum. Furthermore, the full-color grating properties can be modulated through geometric deformation because of the film’s elasticity. Additionally, anticounterfeiting features were also successfully achieved when the polymer films were either engraved with drawings and bent or patterned with fluorophores, which can be revealed under ultraviolet light. The most important aspect of this research is that the preparation of this FPC-structured polymer film is inexpensive and convenient, enabling the mass production of a new generation of smart materials

Prefrontal Lobe Brain Reserve Capacity with Resistance to Higher Global Amyloid Load and White Matter Hyperintensity Burden in Mild Stage Alzheimer’s Disease

<div><p>Background</p><p>Amyloid deposition and white matter lesions (WMLs) in Alzheimer's disease (AD) are both considered clinically significant while a larger brain volume is thought to provide greater brain reserve (BR) against these pathological effects. This study identified the topography showing BR in patients with mild AD and explored the clinical balances among BR, amyloid, and WMLs burden.</p><p>Methods</p><p>Thirty patients with AD were enrolled, and AV-45 positron emission tomography was conducted to measure the regional standardized uptake value ratio (SUVr) in 8 cortical volumes-of- interests (VOIs). The quantitative WMLs burden was measured from magnetic resonance imaging while the normalized VOIs volumes represented BR in this study. The cognitive test represented major clinical correlates.</p><p>Results</p><p>Significant correlations between the prefrontal volume and global (r = 0.470, p = 0.024), but not regional (r = 0.264, p = 0.223) AV-45 SUVr were found. AD patients having larger regional volume in the superior- (r = 0.572, p = 0.004), superior medial- (r = 0.443, p = 0.034), and middle-prefrontal (r = 0.448, p = 0.032) regions had higher global AV-45 SUVr. For global WML loads, the prefrontal (r = -0.458, p = 0.019) and hippocampal volume (r = -0.469, p = 0.016) showed significant correlations while the prefrontal (r = -0.417, p = 0.043) or hippocampal volume (r = -0.422, p = 0.04) also predicted better composite memory scores. There were no interactions between amyloid SUVr and WML loads on the prefrontal volume.</p><p>Conclusions</p><p>BR of the prefrontal region might modulate the adverse global pathological burden caused by amyloid deposition. While prefrontal volume positively associated with hippocampal volume, WMLs had an adverse impact on the hippocampal volume that predicts memory performance in mild stage AD.</p></div

Partial correlations between cortical volume and GM AV-45 SUVr in 30 patients.

<p>Partial correlations between cortical volume and GM AV-45 SUVr in 30 patients.</p

Illustration of automatic quantification of 3D white matter (WM) lesion burden.

<p>(1) Individual T1-weighted image were registered to the corresponding FLAIR images using a 12 degrees of freedom affine transformation. (2) To obtain the transformation matrix, the coregistered T1-weighted images were registered to the averaged customized group T1 template in MNI space. (3) The inverse transformation matrix from step 2 was applied to the AAL template to generate corresponding AAL volumes in each individual's 3D T1WI native space for later calculation of normalized 3D WM volume. (4) WM volume of interest (VOI) on FLAIR sequences (5) Transfer the white matter volume of interest to the corresponding T1 image. (6) 3D WM volume constructions.</p

Model of prefrontal brain reserve with related regional volumes, white matter lesions and amyloid pathological load.

<p>Model of prefrontal brain reserve with related regional volumes, white matter lesions and amyloid pathological load.</p

General characteristics of the Alzheimer's disease patients.

<p>General characteristics of the Alzheimer's disease patients.</p

Prefrontal regions showing brain reserve to amyloid burden or white matter lesion loads.

<p>Prefrontal regions showing brain reserve to amyloid burden or white matter lesion loads.</p

Triboluminescence and Metal Phosphor for Organic Light-Emitting Diodes: Functional Pt(II) Complexes with Both 2‑Pyridylimidazol-2-ylidene and Bipyrazolate Chelates

We report the utilization of both pyrid-2-yl-imidazolylidene and dianionic bipz chelates as constituents in syntheses of a new series of charge-neutral Pt­(II) complexes <b>1</b>–<b>4</b>, among which complex <b>4</b> revealed remarkable triboluminescence, i.e., generation of photoemission upon grinding or cracking of the solid sample. The triboluminescence is found to be sensitive to the subtle changes of the associated substituents of pyrid-2-yl-imidazolylidene chelate, as verified by the disappearance of the triboluminescence for complexes <b>1</b>–<b>3</b>. Alternatively, the well-ordered solid packing of <b>3</b>, as indicated by the grazing incidence X-ray scattering experiment, serves as an ideal emitter for the fabrication of highly efficient OLEDs, rendering high external quantum efficienciy (25.9%) and luminesce efficiency (90 cd A^<b>–</b>1) at the practical brightness of 100 cd m^<b>–</b>2. The rather low roll-off in efficiency (24.4%, 85 cd A^<b>–</b>1 at high brightness of 1000 cd m^–2) is attributed to the short excited-state lifetime of <b>3</b> (∼800 ns) in the solid state, which in turn is associated with the MMLCT transition character