Impact of cirrhosis-related complications on posttransplant survival in patients with acute-on-chronic liver failure.

BACKGROUND: Acute-on-chronic liver failure (ACLF) is a life-threatening syndrome defined as acute decompensation in patients with chronic liver disease. Liver transplantation (LT) is the most effective treatment. We aimed to assess the impact of cirrhosis-related complications pre-LT on the posttransplant prognosis of patients with ACLF. METHODS: This was an observational cohort study conducted between January 2018 and December 2020. Clinical characteristics, cirrhosis-related complications at LT and patient survival post-LT were collected. All liver recipients with ACLF were followed for 1 year post-LT. RESULTS: A total of 212 LT recipients with ACLF were enrolled, including 75 (35.4%) patients with ACLF-1, 64 (30.2%) with ACLF-2, and 73 (34.4%) with ACLF-3. The median waiting time for LT was 11 (4-24) days. The most prevalent cirrhosis-related complication was ascites (78.8%), followed by hepatic encephalopathy (57.1%), bacterial infections (48.1%), hepatorenal syndrome (22.2%) and gastrointestinal bleeding (11.3%). Survival analyses showed that patients with complications at LT had a significantly lower survival probability at both 3 months and 1 year after LT than those without complications (all P < 0.05). A simplified model was developed by assigning one point to each complication: transplantation for ACLF with cirrhosis-related complication (TACC) model. Risk stratification of TACC model identified 3 strata (≥ 4, = 3, and ≤ 2) with high, median and low risk of death after LT (P < 0.001). Moreover, the TACC model showed a comparable ability for predicting the outcome post-LT to the other four prognostic models (chronic liver failure-consortium ACLF score, Chinese Group on the Study of Severe Hepatitis B-ACLF score, model for end-stage liver disease score and Child-Turcotte-Pugh score). CONCLUSIONS: The presence of cirrhosis-related complications pre-LT increases the risk of death post-LT in patients with ACLF. The TACC model based on the number of cirrhosis-related complications pre-LT could stratify posttransplant survival, which might help to determine transplant timing for ACLF.

Effects of Lateral Size, Thickness, and Stabilizer Concentration on the Cytotoxicity of Defect-Free Graphene Nanosheets: Implications for Biological Applications.

In this work, we apply liquid cascade centrifugation to highly concentrated graphene dispersions produced by liquid-phase exfoliation in water with an insoluble bis-pyrene stabilizer to obtain fractions containing nanosheets with different lateral size distributions. The concentration, stability, size, thickness, and the cytotoxicity profile are studied as a function of the initial stabilizer concentration for each fraction. Our results show that there is a critical initial amount of stabilizer (0.4 mg/mL) above which the dispersions show reduced concentration, stability, and biocompatibility, no matter the lateral size of the flakes.

Dispersant-assisted liquid-phase exfoliation of 2D materials beyond graphene.

The extensive research on liquid-phase exfoliation (LPE) performed in the last 10 years has enabled a low cost and mass scalable approach to the successful production of a range of solution-processed 2-dimensional (2D) materials suitable for many applications, from composites to energy storage and printed electronics. However, direct LPE requires the use of specific solvents, which are typically toxic and expensive. Dispersant-assisted LPE allows us to overcome this problem by enabling production of solution processed 2D materials in a wider range of solvents, including water. This approach is based on the inclusion of an additive, typically an amphiphilic molecule, designed to interact with both the nanosheet and the solvent, enabling exfoliation and stabilization at the same time. This method has been extensively used for the LPE of graphene and has been discussed in many reviews, whilst little attention has been given to dispersant-assisted LPE of 2D materials beyond graphene. Considering the increasing number of 2D materials and their potential in many applications, from nanomedicine to energy storage and catalysis, this review focuses on the dispersant-assisted LPE of transition metal dichalcogenides (TMDs), hexagonal boron nitride (h-BN) and less studied 2D materials. We first provide an introduction to the fundamentals of LPE and the type of dispersants that have been used for the production of graphene, we then discuss each class of 2D material, providing an overview on the concentration and properties of the nanosheets obtained. Finally, a perspective is given on some of the challenges that need to be addressed in this field of research.

Fluorescence Lifetime-Tunable Water-Resistant Perovskite Quantum Dots for Multidimensional Encryption.

Using temporal dimension in optical multiplexing is a promising method to increase the security of data encryption. However, adjusting the fluorescence lifetime of light-emitting material often results in inevitable changes in their fluorescence spectra, which is unfavorable for confidential information protection. Here, we report the preparation of various perovskite quantum dot/polymer nanospheres (PQD/polymer) with tunable and long fluorescence lifetimes but identical fluorescence spectra, which are ideal multidimensional data encryption materials. This new data encryption strategy utilizes the water sensitivity of perovskite and achieves spatial dimension encryption of information using different water stabilities between uncoated perovskite quantum dots and PQD/polymer. The fluorescence lifetime of PQD/polymer is used as the coding element to achieve temporal dimension data encryption, and the data are decrypted by fluorescence lifetime imaging microscopy and time-gated luminescence imaging techniques. This study shows the potential of PQD/polymer as a new class of materials for advanced data encryption.

2D bismuthene fabricated via acid-intercalated exfoliation showing strong nonlinear near-infrared responses for mode-locking lasers.

The rediscovery of black phosphorus (BP) has expanded the 2D family into Group 15 (Nitrogen Group) elements, among which bismuthene is the latest member with extraordinary opto-electronic, catalytic and biocompatible properties and potential as a 2D topological insulator. However, bulk Bi is not easily mechanically exfoliated as its counterpart of BP. Thus, to date, the reports on 2D Bi fabrication are rare, and investigations on its nonlinear optical properties are even less. Herein, we rationally designed a new strategy combining acid-interaction and liquid exfoliation to successfully transform metal bulk Bi into few-layer semiconductor, which resulted in unseen opto-electronic properties, such as tunable nonlinear responses all the way to the near-infrared (NIR) region. This band is critical for telecommunication and military purposes, but currently, functioning materials are extremely scarce. The origin of this strong saturable absorption was thoroughly explored through time-resolved spectroscopy spanning from the fs to µs timescale, which indicated ultrafast fs to ps carrier dynamics in the early stage and long exciton bleaching recovery up to µs. As a proof-of-concept application, the as-prepared 2D Bi was employed as a saturable absorber to mode-lock a Tm-doped fiber laser and successfully realized a 2 µm NIR-wavelength output. This study not only offers an effective and scalable method to fabricate the new 2D family member bismuthene with extraordinary stability, but also explores its strong and broad nonlinear responses extending into the NIR region and fundamental photoinduced dynamics, which demonstrate the full potential of 2D Bi for application in opto-electronic devices and nonlinear optics.

Medium-Bandgap Small-Molecule Donors Compatible with Both Fullerene and Nonfullerene Acceptors.

Much effort has been devoted to the development of new donor materials for small-molecule organic solar cells due to their inherent advantages of well-defined molecular weight, easy purification, and good reproducibility in photovoltaic performance. Herein, we report two small-molecule donors that are compatible with both fullerene and nonfullerene acceptors. Both molecules consist of an (E)-1,2-di(thiophen-2-yl)ethane-substituted (TVT-substituted) benzo[1,2-b:4,5-b']dithiophene (BDT) as the central unit, and two rhodanine units as the terminal electron-withdrawing groups. The central units are modified with either alkyl side chains (DRBDT-TVT) or alkylthio side chains (DRBDT-STVT). Both molecules exhibit a medium bandgap with complementary absorption and proper energy level offset with typical acceptors like PC71BM and IDIC. The optimized devices show a decent power conversion efficiency (PCE) of 6.87% for small-molecule organic solar cells and 6.63% for nonfullerene all small-molecule organic solar cells. Our results reveal that rationally designed medium-bandgap small-molecule donors can be applied in high-performance small-molecule organic solar cells with different types of acceptors.

Small molecule-assisted fabrication of black phosphorus quantum dots with a broadband nonlinear optical response.

Ultrathin BP QDs with a uniform size of ∼3.4 nm were prepared via small molecule-assisted liquid phase exfoliation and they exhibited superior broadband nonlinear saturable absorption promising for nonlinear optical applications. Laser photolysis measurement implied that the nonlinear response origin was related to the long-lived electron-hole pairs delocalized within the BP QDs.

Preparation of large size, few-layer black phosphorus nanosheets via phytic acid-assisted liquid exfoliation.

Ultrathin uniform BP nanosheets with lateral dimensions of up to several tens of micrometers were prepared via a small molecule-assisted liquid phase exfoliation method, which exhibited attractive electron accepting abilities from photosensitizers and was thus promising in diverse applications such as photocatalysis and photovoltaics.

Developing carbon-nitride nanosheets for mode-locking ytterbium fiber lasers.

Graphitic carbon nitrides (CNs) have appeared as a new type of photocatalyst for water splitting, but their optical properties (e.g., nonlinear absorption), to the best of our knowledge, have been seldom explored. Here, we report the saturable absorption effects of novel 2D carbon-nitride-type nanosheets and use them as saturable absorbers to passively mode-lock Yb-doped fiber lasers. The CN-based saturable absorber is manufactured by solution coating of 2D CN nanosheets on a gold mirror and has a modulation depth and saturation intensity of 12.5% and 7.5 MW/cm2, respectively. Two different output couplers are employed to construct ring laser cavities. With the 10% coupler, the mode-locked fiber laser produces pulses with duration of ∼310 ps, average power of 1.24 mW, and repetition rate of 7.65 MHz. The laser spectrum is centered at 1066 nm with a bandwidth of 2.4 nm. Increasing the coupling ratio to 50% improves the output power to 2.58 mW but at the same time broadens the pulse width to 420 ps. As a new kind of 2D material with strong saturable absorption, CN nanosheets will open a new way for novel photonic and optoelectronic devices.