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Pancreatic cancer's high fatality rates stem from its resistance to systemic drug delivery and aggressive metastasis, limiting the efficacy of conventional treatments. In this study, two-dimensional ultrathin silicene nanosheets were initially synthesized and near-infrared-responsive two-dimensional silicene-mesoporous silica nanoparticles (SMSNs) were successfully constructed to load the clinically-approved conventional pancreatic cancer chemotherapeutic drug gemcitabine. Experiments on nanoparticle characterization show that they have excellent photothermal conversion ability and stability. Then silicene-mesoporous silica nanoparticles loaded with gemcitabine nanoparticles (SMSN@G NPs) were employed in localized photothermal therapy to control pancreatic tumor growth and achieve therapeutic effects. Our research confirmed the functionality of SMSN@G NPs through immunoblotting and apoptotic assays, demonstrating its capacity to enhance the nuclear translocation of the NF- κ B p65, further affect the protein levels of apoptosis-related genes, induce the apoptosis of tumor cells, and ultimately inhibit the growth of the tumor. Additionally, the study assessed the inhibitory role of SMSN@G NPs on pancreatic neoplasm growth in vivo, revealing its excellent biocompatibility. SMSN@G NPs have a nice application prospect for anti-pancreatic tumors. [ABSTRACT FROM AUTHOR]

We report an unexplored observation of multi-orbital contribution in the below- and near-threshold harmonic generation of aligned molecules. A typical pump–probe configuration is used in our experiments. By scanning the time delay and crossing angle of polarization directions between the pump and probe pulses, we find that the harmonic yield in this region exhibits abnormal intensity-dependent modulation patterns. Further comparison and analysis show that this observation can be interpreted as due to the contribution of deeper-lying molecular orbitals, which are much more prominent than in the above-threshold region and can overall surpass the contribution of the highest occupied molecular orbital, leading to reversed modulation patterns. The particular importance of the deeper-lying orbitals in this regime is closely related to the multi-photon excitation pathways involved in the generation process. Our work will advance further investigations on the mechanism of below- and near-threshold harmonic generation. [ABSTRACT FROM AUTHOR]

Improvement of contact resonance atomic force microscopy (CR-AFM) frequency sensitivity at a high contact stiffness condition and subsequent enhancement of its subsurface imaging capability were demonstrated by adding an additional mass on the cantilever backside near the free end. The influence of mass and its position on the CR-AFM performances was analytically investigated by using a simplified cantilever vibration model and further compared with finite element analysis. Theoretical results and FEA simulations showed good agreement and they could provide a general guide on the cantilever's modification by attaching a proper mass to improve the CR-AFM capability. As a prototype, a Pt micro-disc with precisely controlled size and position on the cantilever, which served as the attached mass, was deposited by utilizing focused ion beam. The improvement of frequency sensitivity was verified through CR spectroscopy and subsurface imaging on cavities having pre-determined diameters and covered with highly oriented pyrolytic graphite flakes. Compared with the original unmodified cantilever, obvious enhancement of CR-AFM subsurface nano-imaging was obtained. The mass-attached cantilever can benefit characterizing sample's mechanical properties and enhancing subsurface imaging based on tip-generated stress. [ABSTRACT FROM AUTHOR]

Magnetic force microscopy (MFM) has become one of the most important instruments for characterizing magnetic materials with nanoscale spatial resolution. When analyzing magnetic particles by MFM, calibration of the magnetic tips using reference magnetic nanoparticles is a prerequisite due to similar orientation and dimension of the yielded magnetic fields. However, in such a calibration process, errors caused by extra electrostatic interactions will significantly affect the output results. In this work, we evaluate the magnetic moment and dipole radius of the MFM tip on Fe3O4 nanoparticles by considering the associated electrostatic force. The coupling of electrostatic contribution on the measured MFM phase is eliminated by combining MFM and Kelvin probe force microscopy together with theoretical modeling. Numerical simulations and experiments on nickel nanoparticles demonstrate the effectiveness of decoupling. Results show that the calibrated MFM tip can enable a more accurate analysis of micro-and-nano magnetism. In addition, a fast and easy calibration method by using bimodal MFM is discussed, in which the acquisition of multiple phase shifts at different lift heights is not required. [ABSTRACT FROM AUTHOR]

Objective. The arrhythmia identification method based on the U-net has the potential for fast application. The RR-intervals have been proven to improve the performance of single-heartbeat identification methods. However, because both the heartbeats number and location in the input of the U-net are unfixed, the approach based on the U-net cannot use RR-intervals directly. To solve this problem, we proposed a novel method. The proposed method also can identify heartbeats of four classes, including non-ectopic (N), supraventricular ectopic beat (SVEB), ventricular ectopic beat (VEB), and fusion beat (F). Approach. Our method consists of the pre-processing and the two-stage identification framework. In the pre-processing part, we filtered input signals with a band-pass filter and created the auxiliary waveforms by RR-intervals. In the first stage of the framework, we designed a network to handle input signals and auxiliary waveforms. We proposed a masking operation to separate the input signal into two signals according to the result of the network. The first signal contains heartbeats of SVEB and VEB. The second signal includes heartbeats of N and F. The second stage consists of two networks and can further identify the heartbeats of SVEB, VEB, N, and F from these two signals. Main result. We validated our method on the MIT-BIH arrhythmia database with the inter-patient model. For classes N, SVEB, VEB, and F, our approach achieved F1 scores of 98.26, 68.61, 95.99, and 47.75, respectively. Significance. Our method not only can effectively utilize RR intervals but also can identify multiple arrhythmias. [ABSTRACT FROM AUTHOR]

A novel method is proposed for designing optimized three-dimensional computer-generated holograms (CGHs). A series of spherical wave factors are introduced into the conventional optimal rotation angle (ORA) algorithm to achieve a varying amount of defocus along the optical axis, and the distraction terms are minimized during the iterative process. Both numerical simulation and experimental reconstructions are presented to demonstrate that this method is able to yield excellent multilayer patterns with high uniformity and signal-to-noise ratio (SNR). This method is significant for applications in laser 3D printing and multilayer data recording. [ABSTRACT FROM AUTHOR]

To enhance contact resonance atomic force microscopy (CR-AFM) and harmonic AFM imaging simultaneously, we design a multifunctional cantilever. Precise tailoring of the cantilever's dynamic properties is realized by either mass-removing or mass-adding. As prototypes, focused ion beam drilling or depositing is used to fabricate the optimized structures. CR-AFM subsurface imaging on circular cavities covered by a piece of highly oriented pyrolytic graphite validates the improved CR frequency to contact stiffness sensitivity. The detectable subsurface depth and cavity radius increase accordingly by using the multifunctional cantilever. At the same time, the free resonance frequency of the second mode is tuned to an integer multiple of the fundamental one. Harmonic AFM imaging on polystyrene and low-density polystyrene mixture shows the improved harmonic amplitude contrast and signal strength on the two material phases. The multifunctional cantilever can be extended to enhance other similar AFM operation modes and it has potential applications in relevant fields such as mechanical characterization and subsurface imaging. [ABSTRACT FROM AUTHOR]