Search

The deposition/stripping behavior of lithium metal is intriguing, and the associated formation of inactive lithium at various temperatures remains elusive, which hinders the practical application of lithium metal batteries. Here, utilizing the variable-temperature operando solid-state nuclear magnetic resonance (SS NMR) technique, we reveal the temperature effects on the lithium microstructure evolution in a carbonate-based electrolyte system. In addition, the mass spectrometry titration (MST) method is used to quantify the evolution of inactive lithium components, including dead lithium, solid electrolyte interface (SEI), and lithium hydride (LiH). Combined SS NMR and MST results show that the morphology of lithium metal is reasonably correlated to the amount of inactive Li formed. At low/ambient temperature, the lithium microstructure has a similar evolution pattern, and its poor morphology leads to a large amount of dead lithium, which dominates capacity loss; however, at high temperature large and dense lithium deposits form with less dead Li detected, and the intensified electrolyte consumption in SEI formation is the major cause for capacity loss. Our phase-field simulation results reveal that the compact lithium deposition formed at higher temperature is due to the more uniformly distributed electric field and Li+concentration. Lastly, two strategies in forming a dense Li deposit are proposed and tested that show performance-enhancing results.

Millimeter wave (mmWave) is a promising future wireless communication technology. To overcome the high path loss in mmWave band, distributed antenna systems (DASs) with each base station (BS) connecting to multiple remote radio units (RRUs) is a candidate solution. To better characterize the small-scale fading of mmWave channels, the fluctuating two-ray (FTR) was recently proposed. In this letter, we study the performance of RRU selection in mmWave DASs over the FTR fading. First, simplified closed-form expressions are, respectively, provided for the probability density function (PDF) and cumulative distribution function (CDF) of signal-to-noise ratio (SNR). Then, we derive the exact closed-form expressions and their high-SNR approximations for the outage probability and ergodic rate, respectively. The effect of RRU number and FTR-fading parameters on the performance are further revealed from these high-SNR approximations. Simulations validate our analytical results.

Photoacoustic imaging (PAI) has attracted great attention in the diagnosis and treatment of diseases due to its noninvasive properties. Especially in the second near-infrared (NIR-II) window, PAI can effectively avoid the interference of tissue spontaneous fluorescence and light scattering, and obtain high resolution images with deeper penetration depth. Because of its ideal spectral absorption and high conversion efficiency, NIR-II PA contrast agents overcome the absorption or emission of NIR-II light by endogenous biomolecules. In recent years, a series of NIR-II PA contrast agents have been developed to improve the performance of PAI in disease diagnosis and treatment. In this paper, the research progress of NIR-II PA contrast agents and their applications in biomedicine are reviewed. PA contrast agents are classified according to their composition, including inorganic contrast agents, organic contrast agents, and hybrid organic–inorganic contrast agents. The applications of NIR-II PA contrast agents in medical imaging are described, such as cancer imaging, inflammation detection, brain disease imaging, blood related disease imaging, and other biomedical application. Finally, the research prospects and breakthrough of NIR-II PA contrast agents are discussed.

This letter investigates the downlink integrated low earth orbit (LEO) satellite-terrestrial millimeter-wave decode-and-forward relay network, where the satellite and terrestrial relays locate in uniform distribution over the spherical cap surface of the LEO and in Poisson point process over the ground, respectively. In order to obtain fine-grained information on the coverage performance, the meta distribution (MD) of signal-to-interference-to-noise ratio (SINR) is adopted for network performance evaluation, which provides the probability that certain percentage of satellite-relays-user links are able to reach a target SINR threshold. The closed-form and analytical expression of the ${b}$ -th moments of the complementary cumulative distribution functions (CCDFs) of SINR for the satellite-to-relay link and relay-to-user link are then derived, respectively. In addition, we further give the analytical MD expression via the beta approximation. Finally, numerical results are provided to validate our analytical results.

Background and Aims: Endoscopic submucosal dissection (ESD) has become the primary option for the treatment of early gastric cancer (EGC). Thus, it is necessary to diagnose whether residual cancer cells exist in the ESD specimen margins, which can affect tumor recurrence and survival rates in the future. Multiphoton microscopy (MPM) can be suitably used for nondestructive imaging of biological tissue on a cellular level to enable real-time guidance during endoscopic therapy. Considering this, the objective of this study is to explore the practicality of MPM for the diagnosis of ESD specimen margins in the case of EGC. Methods: First, a total of 20 surgical samples was imaged using the proposed MPM technique to obtain two-photo excited fluorescence signal from the intrinsic fluorescent substances within cells and second-harmonic generation signal from collagen; these signals were used to determine MPM pathological features for margin diagnosis. Then, a double-blind study of 50 samples was conducted to evaluate the diagnosis results based on the obtained MPM pathological features. Results: Multiphoton microscopy can accurately identify the cytological and morphological differences between tissue in the negative and positive margin. The sensitivity, specificity, accuracy, negative predictive, and positive predictive values of MPM in the diagnosis of ESD specimen margins were 97.62, 75.00, 94.00, 95.35, and 85.71%, respectively. Conclusion: These results indicate that MPM can be used as an effective, real-time, and label-free novel method to determine intraoperative resection margins.

Monitoring and quantifying the evolution of inactive lithium is the key to understanding the failure mechanism of lithium metal anodes. In this article, we comprehensively review the quantitative analysis techniques and related research of inactive lithium, and compare the characteristics and limitations of different techniques, further exploring how to accurately understand the intricate failure modes of lithium metal anodes.

Operando monitoring of internal and local electrochemical processes within lithium-ion batteries (LIBs) is crucial, necessitating a range of non-invasive, real-time imaging characterization techniques including nuclear magnetic resonance (NMR) techniques. This review provides a comprehensive overview of the recent applications and advancements of non-invasive magnetic resonance imaging (MRI) techniques in LIBs. It initially introduces the principles and hardware of MRI, followed by a detailed summary and comparison of MRI techniques used for characterizing liquid/solid electrolytes, electrodes and commercial batteries. This encompasses the determination of electrolytes' transport properties, acquisition of ion distribution profile, and diagnosis of battery defects. By focusing on experimental parameters and optimization strategies, our goal is to explore MRI methods suitable to a variety of research subjects, aiming to enhance imaging quality across diverse scenarios and offer critical physical/chemical insights into the ongoing operation processes of LIBs.

Photodynamic therapy (PDT), with its advantages of high targeting, minimally invasive, and low toxicity side effects, has been widely used in the clinical therapy of various tumors, especially superficial tumors. However, the tumor microenvironment (TME) presents hypoxia due to the low oxygen (O2) supply caused by abnormal vascularization in neoplastic tissues and high O2consumption induced by the rapid proliferation of tumor cells. The efficacy of oxygen‐consumping PDT can be hampered by a hypoxic TME. To address this problem, researchers have been developing advanced nanoplatforms and strategies to enhance the therapeutic effect of PDT in tumor treatment. This review summarizes recent advanced PDT therapeutic strategies to against the hypoxic TME, thus enhancing PDT efficacy, including increasing O2content in TME through delivering O2to the tumors and in situ generations of O2; decreasing the O2consumption during PDT by design of type I photosensitizers. Moreover, recent synergistically combined therapy of PDT and other therapeutic methods such as chemotherapy, photothermal therapy, immunotherapy, and gas therapy is accounted for by addressing the challenging problems of mono PDT in hypoxic environments, including tumor resistance, proliferation, and metastasis. Finally, perspectives of the opportunities and challenges of PDT in future clinical research and translations are provided. This review emphatically focuses on the strategic design in conquering tumor hypoxia for enhanced photodynamic therapy (PDT). The oxygenation modes are categorized as “oxygen‐carrying” and “oxygen‐generating.” Then synergistic effects of combining PDT with other therapeutics to achieve hypoxia tolerance therapy are comprehensively discussed. It is hoped that these inspirations in hypoxia‐associated anti‐tumor therapy will provide perspectives in designing new oxygenation nanomaterials in this promising field.

The clear and accurate understanding of the degree of hepatocellular-carcinoma (HCC) differentiation plays a key role in the determination of the patient prognosis and development of a treatment plan by the clinician. However, label-free and automated classification of the HCC grading is challenging. Here, we demonstrate second-harmonic generation (SHG) microscopy for label-free classification of HCC grading in paraffin-embedded specimens. A total of 217 images from 113 patients were obtained using SHG microscopy, and the SHG signals from the collagen within the tumor were analyzed using feature extraction and selection, the Mann–Whitney test, and the receiver operating characteristic curves. The results exhibit good correlation between the software analysis and the diagnosis by experienced pathologists. Combining the image features and clinical information, an adaptive quantification algorithm is generated for automatically determining the HCC grade. The results suggest that SHG microscopy might be a promising automated diagnostic method for clinical use, without requiring time for tissue processing and staining.

Synthetic micro/nanomotors have great potential in deep tissue imaging and in vivodrug delivery because of their active motion ability. However, applying nanomotors with a size less than 100 nm to in vivoimaging and therapy is one of the core changes in this field. Herein, a nanosized hydrogen peroxide (H2O2)-driven Janus gold nanorod-platinum (JAuNR-Pt) nanomotor is developed for enhancing the second near-infrared region (NIR-II) photoacoustic (PA) imaging of deep tissues of tumors and for effective tumor treatment. The JAuNR-Pt nanomotor is prepared by depositing platinum (Pt) on one end of a gold nanorod with varying proportions of Pt shell coverage, including 10%, 25%, 50%, 75%, and 100%. The JAuNR-Pt nanomotor with Pt shell coverage proportions of 50% exhibits the highest diffusion coefficient (De), and it can rapidly move in the presence of H2O2. The self-propulsion of JAuNR-Pt nanomotor enhances cellular uptake, accelerates lysosomal escape, and facilitates continuous release of cytotoxic Pt2+ions to the nucleus, causing DNA damage and cell apoptosis. The JAuNR-Pt nanomotor presents deep penetration and enhanced accumulation in tumors as well as high tumor treatment effect. Therefore, this work displays deep tumor imaging and an excellent antitumor effect, providing an effective tool for accurate diagnosis and treatment of diseases.

As key characteristic molecules, several H2S-activated probes have been explored for colon cancer studies. However, a few ratiometric fluorescence (FL) probes with NIR-II emissions have been reported for the quantitative detection of H2S in colon cancer in vivo. Here, we developed an in situH2S-activatable ratiometric nanoprobe with two NIR-II emission signals for the detection of H2S and intelligently lighting up colon cancer. The nanoprobe comprised a down conversion nanoparticle (DCNP), which emitted NIR-II FL at 1550 nm on irradiation with a 980 nm laser (F1550Em, 980Ex). Further, human serum albumin (HSA) was combined with Ag+on the surface of DCNP to form a DCNP@HSA-Ag+nanoprobe. In the presence of H2S, Ag2S quantum dots (QDs) were formed in coated HSA, which emitted FL at approximately 1050 nm on irradiation with an 808 nm laser (F1050Em, 808Ex) through an H2S-induced chemical reaction between H2S and Ag+; however, the FL signal of DCNP was stable at 1550 nm (F1550Em, 980Ex), generating a H2S concentration-dependent ratiometric F1050Em, 808Ex/F1550Em, 980Exsignal. The NIR-II ratiometric nanoprobe was successfully used for the accurate quantitative detection of H2S and the detection of the precise location of colon cancer through an endogenous H2S-induced in situreduction reaction to form Ag2S QDs. Thus, these findings provide a new strategy for the specific detection of targeted molecules and diagnosis of disease based on the in situ-activatable NIR-II ratiometric FL nanoprobe.