Topochemical Polymerization at Diacetylene Metal-Organic Framework Thin Films for Tuning Nonlinear Optics.

Developing the topochemical polymerization of metal-organic frameworks (MOFs) is of pronounced significance for expanding their functionalities but is still a challenge on third-order nonlinear optics (NLO). Here, we report diacetylene MOF (CAS-1-3) films prepared using a stepwise deposition method and film structural transformation approach, featuring dynamic structural diversity. The MOF structures were determined by the three-dimensional electron diffraction (3D ED) method from nanocrystals collected from the films, which provides a reliable strategy for determining the precise structure of unknown MOF films. We demonstrate the well-aligned diacetylene groups in the MOFs can promote topological polymerization to produce a highly conjugated system under thermal stimulation. As a result, the three MOF films have distinct NLO properties: the CAS-1 film exhibits saturable absorption (SA) while CAS-2 and CAS-3 films exhibit reverse saturable absorption (RSA). Interestingly, due to the topochemical polymerization of the MOF films, a transition from SA to RSA response was observed with increasing temperatures, and the optical limiting effect was significantly enhanced (∼46 times). This study provides a new strategy for preparing NLO materials and thermally regulation of nonlinear optics.

Chiral Liquid Crystalline Metal-Organic Framework Thin Films for Highly Circularly Polarized Luminescence.

Combining metal-organic frameworks (MOFs) with liquid crystals to construct liquid crystalline MOFs (LCMOF) offers the advantage of endowing and enhancing their functionality, yet it remains a challenging task. Herein, we report chiral liquid crystalline MOF (CLCMOF) thin films by cross-linking the chiral liquid crystals (CLC) with MOF thin films to realize highly circular polarization luminescence (CPL) performance with photo and thermal switching. By layer by layer cross-linking stilbene-containing CLC with stilbene-based MOF (CLC/MOF) thin film, the CLCMOF thin films were successfully obtained after UV irradiation due to the abundant [2 + 2] photocycloaddition. The resulted CLCMOF thin films have strong chirality, obvious photochromic fluorescent, and strong CPL performance (the asymmetry factor reaches to 0.4). Furthermore, due to the photochromic fluorescent MOF and thermotropic CLC, the CPL can be reversed and red-shifted after heating and UV irradiation treatment, showing photo- and thermal CPL switching. Such MOF-based CPL thin films with photo/thermal CPL switching were prepared to patterns and codes for the demonstration of potential application in advanced information anticounterfeit and encryption. This study not only opens a strategy for developing chiral thin films combining MOFs and liquid crystals but also offers a new route to achieve CPL switching in optical applications.

Age-related severity and distribution of haemophilic arthropathy of the knee, ankle and elbow among Chinese patients with haemophilia.

INTRODUCTION AND AIMS: Age-related severity and distribution of haemophilic arthropathy (HA) among Chinese patients with haemophilia using the Haemophilia Early Detection with Ultrasound (HEAD-US) system have not been extensively studied. METHODS: In our study, 89 patients with moderate and severe haemophilia were recruited. A total of 534 joints (knees, ankles and elbows on both sides included) were evaluated using musculoskeletal ultrasound (MSKUS) and scored using the HEAD-US system. RESULTS: Prevalence and average number of HA were 39.1% and 0.7, 90.6% and 3.2, 94.1% and 4.5, and 100% and 4.3 for ages ≤10, 11-20, 21-30 and 31-40 years, respectively. Prevalence and mean number of knee, ankle and elbow arthropathies also increased with age, although joint damages progressed in unparallel patterns. A significant difference in synovium subscores was observed between patients aged <10 and >10 years. An increasing tendency was observed in cartilage and subchondral bone subscores along with age before 30 years. No significant difference in mean joint scores was found between patients receiving on-demand therapy and those receiving on-demand to low-dose prophylactic therapy. CONCLUSIONS: Haemophilic arthropathy developed in early childhood and progressed mainly before 30 years of age among Chinese patients with haemophilia, although in different ways among the knee, ankle and elbow.

[Contrast-enhanced ultrasonography in the diagnosis of venous erectile dysfunction].

OBJECTIVE: To investigate the effect and safety of contrast-enhanced ultrasonography (CEUS) in the diagnosis of venous erectile dysfunction (VED). METHODS: From June 2015 to March 2016, 43 ED patients underwent corpus cavernography, of whom 23 were diagnosed with and the other 20 without corpus cavernosal venous leakage (CCVL). All the patients received intracorporal injection of a vasoactive drug and CEUS. RESULTS: Of the 23 patients with CCVL, 21 were confirmed by CEUS, including 12 cases of double venous leakage, 2 cases of single venous leakage, 5 cases of crural venous leakage, and 2 cases of the mixed type, while the other 2 showed no CCVL on CEUS. Of the 20 patients with CCVL, 2 presented CCVL on CEUS. CONCLUSIONS: CEUS has the advantages of accuracy, safety, and less invasiveness in the diagnosis of VED.

Photo-Curable 3D Printing of Circularly Polarized Afterglow Metal-Organic Framework Monoliths.

Developing coordination complexes (such as metal-organic frameworks, MOFs) with circularly polarized luminescence (CPL) is currently attracting tremendous attention and remains a significant challenge in achieving MOF with circularly polarized afterglow. Herein, MOFs-based circularly polarized afterglow is first reported by combining the chiral induction approach and tuning the afterglow times by using the auxiliary ligands regulation strategy. The obtained chiral R/S-ZnIDC, R/S-ZnIDC(bpy), and R/S-ZnIDC(bpe)(IDC = 1H-Imidazole-4,5-dicarboxylate, bpy = 4,4'-Bipyridine, bpe = trans-1,2-Bis(4-pyridyl) ethylene) containing a similar structure unit display different afterglow times with 3, 1, and <0.1 s respectively which attribute to that the longer auxiliary ligand hinders the energy transfer through the hydrogen bonding. The obtained chiral complexes reveal a strong chiral signal, obvious photoluminescence afterglow feature, and strong CPL performance (glum up to 3.7 × 10-2). Furthermore, the photo-curing 3D printing method is first proposed to prepare various chiral MOFs based monoliths from 2D patterns to 3D scaffolds for anti-counterfeiting and information encryption applications. This work not only develops chiral complexes monoliths by photo-curing 3D printing technique but opens a new strategy to achieve tunable CPL afterglow in optical applications.

Characterization of anisotropy of elastic modulus with three-dimensional freehand scan shear wave elasticity imaging.

Purpose: The purpose of this study is to develop a freehand scan three-dimensional (3D) shear wave elasticity imaging (SWEI) method for characterizing the anisotropy of elastic properties in biological tissues. The motivation behind this work lies in addressing the limitations of traditional two-dimensional (2D) SWEI, which only measures shear wave speeds in a single direction, as well as fulfilling the clinical demand for improved medical imaging. Approach: Our imaging system utilizes a high-definition optical camera to continuously track the ultrasonic transducer, collecting spatial position-angle data of the transducer and corresponding two-dimensional SWEI data. By reconstructing three-dimensional SWEI images using these data, we achieved freehand SWEI. Results: We validated the accuracy of 2D SWEI on a standard elastic phantom, and then performed 3D SWEI on the pork tenderloin and the triceps brachii of two volunteers. We obtained shear wave speed of 1.82 to 3.12 m/s in the pork tenderloin, shear wave speed of 1.16 to 2.36 m/s in the triceps brachii of non-exercising volunteers, and shear wave speed of 0.55 to 1.63 m/s in the triceps brachii of exercising volunteers, and the maximum shear wave speed directions were generally aligned with the orientation of muscle fibers. Conclusions: We proposed a method that can overcome the limitations of 2D-SWEI regarding imaging angle while also extending the imaging angle of 3D-SWEI, which could have significant implications for improving the accuracy and safety of medical diagnoses.