General Synthesis of Large Inorganic Nanosheets via 2D Confined Assembly of Nanoparticles

Assembling nanoparticles to spatially well-defined functional nanomaterials and sophisticated architectures has been an intriguing goal for scientists. However, maintaining a long-range order of assembly to create macrostructures remains a challenge, owing to the reliance on purely interparticle interactions. Here, we present a general strategy to synthesize a class of inorganic nanosheets via a bottom-up directional freezing method. We demonstrate that, by confining a homogeneously dispersed metal-cyano colloidal suspension at the ice-water interface, followed by removal of ice crystals, large nanosheets with a lateral scale of up to several millimeters can be produced. The formation of millimeter-sized nanosheets is attributed to balanced electrostatic forces between dispersed nanoparticles, coupled with an appropriate hydrodynamic size of nanoparticles, potentially favorable lattice matching between nanoparticles and ice crystals, and the intermediate water at the ice-particle interface. The highly anisotropic growth of ice crystals can therefore guide the 2D confined assembly of nanoparticles in a long-range order, leading to well-defined 2D nanosheets. This contribution sheds light on the potential of nanoparticle assembly at larger length scales in designing families of large 2D nanoarchitectures for practical applications.

Emerging Electrochemical Techniques for Probing Site Behavior in Single-Atom Electrocatalysts

Single-atom catalysts (SACs) have aroused tremendous interest over the past decade, particularly in the community of energy and environment-related electrocatalysis. A rapidly growing number of recent publications have recognized it as a promising candidate with maximum atomic utilization, distinct activity, and selectivity in comparison to bulk catalysts and nanocatalysts. However, the complexity of localized coordination environments and the dispersion of isolated sites lead to significant difficulties when it comes to gaining insight into the intrinsic behavior of electrocatalytic reactions. Furthermore, the low metal loadings of most SACs make conventional ensemble measurements less likely to be accurate on the subnanoscale. Thus, it remains challenging to probe the activity and properties of individual atomic sites by available commercial instruments and analytical methods. In spite of this, continuing efforts have lately focused on the development of advanced measurement methodologies, which are very useful to the fundamental understanding of SACs. There have recently been a number of in situ/operando techniques applied to SACs, such as electron microscopy, spectroscopy, and other analysis methods, which support relevant functions to identify the active sites and reaction intermediates and to investigate the dynamic behavior of localized structures of the catalytic sites.This Account aims to present recent electrochemical probing techniques which can be used to identify single-atomic catalytic sites within solid supports. First, we describe the basic principles of molecular probe methods for the study and analysis of electrocatalytic site behavior. In particular, the in situ probing technique enabled by surface interrogation scanning electrochemical microscopy (SI-SECM) can measure the active site density and kinetic rate with high resolution. An alternative electrochemical probing technique is further demonstrated on the basis of single-entity electrochemistry, which allows the unique electrochemical imaging of the size and catalytic rate of single atoms, molecules, and clusters. The merits and limitations of different electrochemical techniques are then discussed, along with perspectives for future prospects. Apart from this, we further showcase the powerful capability of emerging electrochemical probing techniques for determining significant effects and properties of SACs for various electrocatalytic reactions, including oxygen reduction and evolution, hydrogen evolution, and nitrate reduction. Overall, electrochemical techniques with atomic resolution have greatly increased opportunities for observing, measuring, and understanding the surface and interface chemistry during energy conversion. In the future, it is anticipated that the development of electrochemical probing techniques will be advanced with innovative perspectives on the behavior and features of SACs. We hope that this Account can contribute in several ways to promoting the fundamental knowledge and technical progress of emerging electrochemical measurements for studying SACs.

Porous Two-dimensional Iron-Cyano Nanosheets for High-rate Electrochemical Nitrate Reduction

Ammonia (NH₃) is an essential ingredient in agriculture and a promising source of clean energy as a hydrogen carrier. The current major method for ammonia production, however, is the Haber-Bosch process that leads to massive energy consumption and severe environmental issues. Compared with nitrogen (N₂) reduction, electrochemical nitrate reduction reaction (NO₃RR), with a higher NH₃ yield rate and Faradaic efficiency, holds promise for efficient NH₃ production under ambient conditions. To achieve efficient NO₃RR, electrocatalysts should exhibit high selectivity and Faradaic efficiency with a high NH₃ yield rate. In this work, we developed two-dimensional (2D) iron-based cyano-coordination polymer nanosheets (Fe-cyano NSs) following in situ electrochemical treatment for high-rate NO₃RR. Owing to the strong adsorption of nitrate on Fe⁰ active sites generated via topotactic conversion and in situ electroreduction, 2D Fe-cyano electrocatalyst exhibits high catalytic activity with a yield rate of 42.1 mg h^-1 mg_cat^-1 and a Faradaic efficiency of over 90% toward NH₃ production at -0.5 V (vs reversible hydrogen electrode, RHE). Further electrochemical characterizations revealed that superhydrophilic surface and enhanced electrochemical surface area of the 2D porous nanostructures also contributed to the high-rate NO₃RR activity. An electrolyzer toward NO₃RR and oxygen evolution reaction (OER) in a two-electrode configuration is constructed based on 2D Fe-cyano, achieving an energy efficiency of 26.2%. This work provides an alternative methodology toward topotactic conversion of transition metal nanosheets for NO₃RR and reveals the often-overlooked contribution of hydrophilicity of the catalysts for high-rate electrocatalysis.

Long Noncoding RNA HAND2-AS1 Suppresses Cell Proliferation, Migration, and Invasion of Bladder Cancer via miR-17-5p/KLF9 Axis

Bladder cancer (BC) is the most common type of malignant tumor in the genitourinary system. Through the microarray analysis of clinical samples, long noncoding RNA HAND2-AS1 expression was found to be downregulated in BC tissues. However, the function of HAND2-AS1 on BC and underlying mechanism are unclear. In this study, the correlations of HAND2-AS1 with clinicopathological parameters in BC patients were determined. The gain- and loss-of-function experiments were conducted to examine the role of HAND2-AS1 in malignant behaviors of BC cells in vitro and in vivo. Then, we paid attention to miR-17-5p/KLF9 axis to illustrate the molecular mechanism. Results showed that HAND2-AS1 was downregulated in BC tissues, and its overexpression significantly inhibited cell proliferation, migration, and invasion in vitro, as well as tumor growth in vivo. Knockdown of HAND2-AS1 caused an opposite effect on BC cell malignancies. Furthermore, miR-17-5p was shown to be a direct target of HAND2-AS1, and it reversed the inhibitory effect of HAND2-AS1 on BC malignancies. Also, as a downstream factor of miR-17-5p, KLF9 silencing was demonstrated to mediate the role of miR-17-5p inhibitor in BC cell proliferation and invasion. Thus, it suggests that HAND2-AS1 acts as a suppressor in BC development through miR-17-5p/KLF9 axis.

The efficacy of 99mTc-rituximab as a tracer for sentinel lymph node biopsy in cutaneous melanoma patients

Background

The sentinel lymph node (SLN) status is a vital prognostic factor for malignant melanoma (MM) patients. There is increasing evidence that a radioactive agent, rather than its combination with blue dye, is sufficient for a SLN biopsy (SLNB). Thus, we discussed the efficacy of ^99mTc-rituximab as a tracer in MM patients.

Methods

A total of 502 consecutive patients with MM who underwent SLNB were enrolled in this study. All participants were peritumorally injected with ^99mTc-rituximab before imaging, and scanned with single-photon emission computed tomography-computed tomography (SPECT-CT) to detect the number and location of the SLN. A gamma detection probe was employed to detect radioactive SLNs in operation. Follow up was conducted to observe whether nodal or distant recurrence occurred.

Results

The SLNs were successfully imaged via SPECT-CT and harvested from all 502 participants. No drainage tube was indwelled and 32 (6.3%) participants experienced the following complications: seroma (n=26, 5.2%), wound infections or lymphangitis (n=6, 1.2%), sensory nerve injuries (n=4, 0.8%). There were 380 patients who were diagnosed as SLN-negative and 122 (24.2%) were SLN-positive. A total of 85 SLN-positive patients received complete lymph node dissection, and 28 (32.9%) had additional positive lymph nodes. During a median follow-up of 24 months, 28 participants were found to have a false negative (FN) SLN. The FN rate was 18.7%. A higher T stage was a predictive factor for FN [odds ratio (OR) 1.77; P<0.05]. There was no significant difference in the positive or FN rate between the acral and cutaneous groups.

Conclusions

The radiopharmaceutical ^99mTc-rituximab could be employed as a simple and safe tracer in acral and cutaneous melanoma SLN biopsies.

On-chip microdisk laser on Yb3+-doped thin-film lithium niobate

We demonstrate an on-chip Yb³⁺-doped lithium niobate (LN) microdisk laser. The intrinsic quality factors of the fabricated Yb³⁺-doped LN microdisk resonator are measured up to 3.79×10⁵ at a 976 nm wavelength and 1.1×10⁶ at a 1514 nm wavelength. The multi-mode laser emissions are obtained in a band from 1020 to 1070 nm pumped by a 984 nm laser and with the low threshold of 103µW, resulting in a slope efficiency of 0.53% at room temperature. Furthermore, both the second-harmonic frequency of pump light and the sum frequency of the pump light and laser emissions are generated in the on-chip Yb³⁺-doped LN microdisk, benefiting from the strong χ⁽²⁾ nonlinearity of LN. These microdisk lasers are expected to contribute to the high-density integration of a lithium niobate on insulator-based photonic chip.

Super-Resolution Velocity Reconstruction and Control of Ultrasonic Motors

Accurate and fast velocity feedback signal is essential for the velocity control of ultrasonic motors (USMs). However, the low operating velocity of USMs results in a long velocity detection dead time (VDDT) of incremental encoders, which seriously restricts the dynamic control performance of USMs. Therefore, this article presents a super-resolution velocity control (SRVC) scheme based on the velocity reconstruction for the USM. First, the mathematical model of the USM is derived from the mechanical characteristics and the electromechanical coupling characteristics. Then, the velocity reconstruction method is proposed by combining the model estimated velocity and the encoder measured velocity. The closed-loop control scheme using the reconstructed velocity is implemented by a self-designed driving circuit. Experimental results show the velocity reconstruction method not only can break through the limitation of the encoder resolution to reduce the VDDT but also has a high-velocity accuracy. Furthermore, compared with the existing encoder-based control scheme, the proposed SRVC scheme has a faster velocity response under different loads.

High-Throughput Identification of Allergens in a Food System via Hybridization Probe Cluster-Targeted Next-Generation Sequencing

Food allergies (FAs) are a crucial public health problem and a severe food safety issue, resulting in an urgent need for an accurate method to detect all of the hidden allergens that exist in food systems. Current methods for detecting allergens typically utilize ELISA, PCR, or LC-MS, which are suitable for the confirmatory analysis of allergens from ingredients rather than unintended contaminants. In this study, we demonstrate a hybridization probe cluster-targeted next-generation sequencing (HPC-NGS) platform for high-throughput screening of potential allergens in food systems. The HPC-NGS successfully captured target DNA fragments and identified 19 allergenic ingredients in a complex food system. Additionally, the HPC-NGS provided expected allergenic species matching rates of 94.24-100% in single food materials and 99.87-99.98% in processed food products. Thus, HPC-NGS enables the accurate characterization of allergenic ingredients and unintended allergenic contaminants in foods. Our results provide new perspectives on the use of HPC-NGS in the accuracy of high-throughput detection technologies for allergens imposed by the complex matrix effect.

KIF18B promotes tumor progression in osteosarcoma by activating β-catenin

Objective: Osteosarcoma is a common primary highly malignant bone tumor. Kinesin family member 18B (KIF18B) has been identified as a potential oncogene involved in the development and metastasis of several cancer types. While KIF18B overexpression in osteosarcoma tissue is clearly detected, its specific function in the disease process remains to be established.

Methods:KIF18B expression was assessed in osteosarcoma tissues and cells. We additionally evaluated the effects of KIF18B on proliferation, migration, and invasion of osteosarcoma cells, both in vitro and in vivo.

Results: Our results showed overexpression of KIF18B in osteosarcoma tissues and cells. Knockdown of KIF18B induced G1/S phase arrest and significantly inhibited proliferation, migration, and invasion of osteosarcoma cells, both in vitro and in vivo. KIF18B regulated β-catenin expression at the transcriptional level by controlling nuclear aggregation of ATF2 and at the post-transcriptional level by interacting with the adenomatous polyposis coli (APC) tumor suppressor gene in osteosarcoma cells.

Conclusions: KIF18B plays a carcinogenic role in osteosarcoma by regulating expression of β-catenin transcriptionally via decreasing nuclear aggregation of ATF2 or post-transcriptionally through interactions with APC. Our collective findings support the potential utility of KIF18B as a novel prognostic biomarker for osteosarcoma.

GmoDetector: An accurate and efficient GMO identification approach and its applications

The rapid increase of genetically modified organisms (GMOs) entering the food and feed markets, and the contamination of donor (micro)organisms of transgenic elements make it more challenging for the existing GMO detection. In this study, we developed a high-throughput and contamination-removal GMO detection approach named as GmoDetector. GmoDetector targeted 64 common transgenic elements and 76 GMO-specific events collected from 251 singular GM events, and combined with next generation sequencing (NGS) and target enrichment technology to detect various GMOs. As a result, GmoDetector was able to exclude the donor (micro)organism contamination, and detect the authorized and unauthorized GMOs (UGMOs) in any forms of food or feed, such as processed or unprocessed. The sensitivity of GmoDetector is as low as 0.1% (GMO content), which has met the GMO labeling threshold for all countries. Therefore, GmoDetector is a robust tool for accurate and efficient detection of the authorized and UGMOs.

High-Q microresonators on 4H-silicon-carbide-on-insulator platform for nonlinear photonics

The realization of high-quality (Q) resonators regardless of the underpinning material platforms has been a ceaseless pursuit, because the high-Q resonators provide an extreme environment for confining light to enable observations of many nonlinear optical phenomenon with high efficiencies. Here, photonic microresonators with a mean Q factor of 6.75 × 10⁶ were demonstrated on a 4H-silicon-carbide-on-insulator (4H-SiCOI) platform, as determined by a statistical analysis of tens of resonances. Using these devices, broadband frequency conversions, including second-, third-, and fourth-harmonic generations have been observed. Cascaded Raman lasing has also been demonstrated in our SiC microresonator for the first time, to the best of our knowledge. Meanwhile, by engineering the dispersion properties of the SiC microresonator, we have achieved broadband Kerr frequency combs covering from 1300 to 1700 nm. Our demonstration represents a significant milestone in the development of SiC photonic integrated devices.

Monolithically integrated electro-optic modulator fabricated on lithium niobate on insulator by photolithography assisted chemo-mechanical etching

Integrated electro-optic (EO) modulators are one of the building blocks of photonic integrated circuits. Here, we design and fabricate an EO Mach–Zehnder waveguide modulator on lithium niobate on insulator using photolithography assisted chemo-mechanical etching technology. We optimize the performance of multi-mode interferometer which serves as the 3 dB splitter as well as that of the inverse taper to achieve efficient fiber-waveguide coupling, resulting in a fiber-to-fiber insert loss of 7.6 dB for the fabricated device, with a half wave voltage (HWV) (Vπ ) of 0.84 V and a HWV-length product (Vπ × L) of 3.4 V cm. The all-optical-lithography fabrication approach holds the promising potential for mass production of EO modulators of cost-effectiveness and low Vπ .

Structurally Dynamic Hydrogels for Biomedical Applications: Pursuing a Fine Balance between Macroscopic Stability and Microscopic Dynamics

Owing to their unique chemical and physical properties, hydrogels are attracting increasing attention in both basic and translational biomedical studies. Although the classical hydrogels with static networks have been widely reported for decades, a growing number of recent studies have shown that structurally dynamic hydrogels can better mimic the dynamics and functions of natural extracellular matrix (ECM) in soft tissues. These synthetic materials with defined compositions can recapitulate key chemical and biophysical properties of living tissues, providing an important means to understanding the mechanisms by which cells sense and remodel their surrounding microenvironments. This review begins with the overall expectation and design principles of dynamic hydrogels. We then highlight recent progress in the fabrication strategies of dynamic hydrogels including both degradation-dependent and degradation-independent approaches, followed by their unique properties and use in biomedical applications such as regenerative medicine, drug delivery, and 3D culture. Finally, challenges and emerging trends in the development and application of dynamic hydrogels are discussed.

Electro-optically tunable microring laser monolithically integrated on lithium niobate on insulator

We demonstrate monolithic integration of an electro-optically (EO) tunable microring laser on lithium niobate on insulator (LNOI) platform. The device is fabricated by photolithography assisted chemo-mechanical etching, and the pump laser is evanescently coupled into the erbium (${\rm{E}}{{\rm{r}}^{3 +}}$)-doped lithium niobate (LN) microring laser using an undoped LN waveguide mounted above the microring. The quality factor of the LN microring resonator is measured as high as ${1.54} \times {{1}}{{{0}}^5}$ at the wavelength of 1542 nm. Lasing action can be observed at a pump power threshold below 3.5 mW using a 980 nm continuous-wave pump laser. Finally, tuning of the laser wavelength is achieved by varying the electric voltage on the microelectrodes fabricated in the vicinity of a microring waveguide, showing an EO coefficient of 0.33 pm/V.

Real-world experience with pembrolizumab in patients with advanced soft tissue sarcoma

Background

The goal of this study was to retrospectively analyze the efficacy and safety of pembrolizumab in the real-world treatment of soft tissue sarcoma (STS).

Methods

We analyzed 38 patients who suffered from STS and received pembrolizumab treatment from July 2017 to December 2018 in our hospital. We investigated the influence of clinical characteristics, treatment timing, and treatment protocol on objective response rate (ORR). We also investigated the factors affecting overall survival (OS) and progression-free survival (PFS), as well as the occurrence of severe adverse events (SAEs).

Results

The overall ORR was 19.4% (7/36). The ORRs of patients who received pembrolizumab treatment as first-line, second-line, and third-line therapy were 42.9% (3/7), 25.0% (4/16), and 0% (0/13), respectively, which showed marginal significance (P=0.052). Four patients (11.1%) maintained a complete response (CR) or partial response (PR) for at least 6 months with pembrolizumab monotherapy, or after withdrawal of chemotherapy or targeted therapy regimens. The median PFS was 2.9 months [95% confidence interval (CI): 2.4–3.4 months] and the median OS was 12.0 months (95% CI: 10.2–13.8 months). Cox regression analysis showed that treatment time was an independent factor affecting PFS (P=0.041), while Eastern Cooperative Oncology Group (ECOG) performance status (PS) score was the only independent factor affecting OS (P=0.028).

Conclusions

In the real world, the effectiveness of pembrolizumab in the treatment of STS was low. Some subtypes showed a limited response to pembrolizumab, including alveolar soft part sarcoma (ASPS), undifferentiated pleomorphic sarcoma (UPS), exoskeletal chondrosarcoma (ESCS), and angiosarcoma (AS), while the response in leiomyosarcoma (LMS) was low. Combination therapy may increase the risk of SAEs, especially when combined with pazopanib.

On-chip tunable microdisk laser fabricated on Er3+-doped lithium niobate on insulator

We demonstrate a C-band wavelength-tunable microlaser with an Er³⁺-doped high quality (∼1.8×10⁶) lithium niobate microdisk resonator. With a 976 nm continuous-wave pump laser, lasing action can be observed at a pump power threshold lower than 400 µW at room temperature. Furthermore, the microdisk laser wavelength can be tuned by varying the pump laser power, showing a tuning efficiency of ∼-17.03pm/mW at low pump power below 13 mW, and 10.58 pm/mW at high pump power above 13 mW.

Gel-Derived Amorphous Bismuth-Nickel Alloy Promotes Electrocatalytic Nitrogen Fixation via Optimizing Nitrogen Adsorption and Activation

To achieve the electrochemical nitrogen reduction reaction (NRR) for efficient and sustainable NH₃ production, catalysts should exhibit high selectivity and activity with optimal adsorption energy. Herein we developed a three-dimensional (3D) amorphous BiNi alloy toward a significantly enhanced NRR compared with its crystalline and metal counterparts. Ni alloying enables the chemisorption of nitrogen and the lower free-energy change for the *NNH formation, and the 3D alloy electrocatalyst exhibits high catalytic activity for NH₃ production with a yield rate of 17.5 μg h^-1  mg_cat ^-1 and Faradaic efficiency of 13.8 %. The enhanced electron transfer and increased electrochemical surface area were revealed in the interconnected porous scaffold, affording it sufficiently efficient and stable activity for potential practical applications. This work offers new insights into optimizing the adsorption energy of reactants and intermediates combined with tuning the crystallinity of NRR electrocatalysts.