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Superconducting flip-chip devices using indium microspheres on Au-passivated Nb or NbN as under-bump metallization layer
Superconducting flip-chip interconnects are crucial for the three-dimensional integration of superconducting circuits in sensing and quantum technology applications. We demonstrate a simplified approach for a superconducting flip-chip device using commercially available indium microspheres and an in-house-built transfer stage for bonding two chips patterned with superconducting thin films. We use a gold-passivated niobium or niobium nitride layer as an under-bump metallization (UBM) layer between an aluminum-based superconducting wiring layer and the indium interconnect. At millikelvin temperatures, our flip-chip assembly can transport a supercurrent with tens of milliamperes, limited by the smallest geometric feature size and critical current density of the UBM layer and not by the indium interconnect. We show that the pressed indium interconnect itself can carry a supercurrent exceeding 1 A due to its large size of about 500 μm diameter. Our flip-chip assembly does require neither electroplating nor patterning of indium. The assembly process does not need a flip-chip bonder and can be realized with a transfer stage using a top chip with transparency or through-vias for alignment. These flip-chip devices can be utilized in applications that require few superconducting interconnects carrying large currents at millikelvin temperatures.
Resurgence of common respiratory viruses and mycoplasma pneumoniae after ending the zero-COVID policy in Shanghai
A synaptic transistor with a stacked layer of SiNx and SiO2 deposited from hexamethyldisiloxane/O2
Herein, we employed inductively coupled plasma enhanced chemical vapor deposition using a hexamethyldisiloxane/O2 precursor to deposit SiO2 with electrical double layer capacitance on SiNx forming SiO2/SiNx stacked films as a dielectric layer, achieving high-performance synaptic transistors. The effect of O2 concentration during SiO2 deposition on the transistor performance was investigated. The results of Fourier transform infrared spectroscopy and x-ray photoemission spectroscopy confirm that increasing O2 concentration during deposition boosts the amounts of protons moving between the bridging oxygen in the Si–O–Si network, improving the electrical double layer capacitance of SiO2. Furthermore, SiNx in the stacked structure exhibits a higher relative permittivity than SiO2, resulting in a more concentrated electric field within the SiO2 layer, facilitating proton ionization. SiO2/SiNx stacked film with SiO2 deposited at the oxygen flow rate of 150 sccm exhibited the maximum capacitance of 2.87 μF/cm2 at 4 Hz. The transistor with SiO2 deposited at the oxygen flow rate of 150 sccm achieved the maximum paired pulse facilitation index of 132.9% and the maximum A50/A1 index of 155.4%. This work demonstrates that SiO2 deposited via inductively coupled plasma enhanced chemical vapor deposition using a hexamethyldisiloxane/O2 precursor for application potential in artificial neuromorphic computing.
Temperature dynamics and mechanical properties analysis of carbon fiber epoxy composites radiated by nuclear explosion simulated light source
Geometric effects in the measurement of the remanent ferroelectric polarization at the nanoscale
A resurgence of research on ferroelectric materials has recently occurred due to their potential to enhance the performance of memory and logic. For the design and commercialization of such technologies, it is important to understand the physical behavior of ferroelectrics and the interplay with device size, geometry, and fabrication processes. Here, we report a study of geometric factors that can influence the measurement of the remanent ferroelectric polarization, an important measurement for understanding wakeup, retention, and endurance in ferroelectric technologies. The areal size scaling of W/Hf0.5Zr0.5O2/W capacitors is compared in two typical structures: an island top electrode with a continuous ferroelectric layer and an island top electrode/ferroelectric layer (etched ferroelectric layer). Error in the evaluation of the switched area leads to anomalous scaling trends and increasing apparent remanent polarization as capacitor sizes decrease, most strongly in continuous ferroelectric layer capacitors. Using TEM and electric field simulations, this is attributed to two effects: a processing artifact from ion milling that creates a foot on the top electrode and a fringe electric field penetrating outside of the capacitor area. With the correction of the switching area, the 2Pr for both samples agree (∼32 μC cm−2) and is invariant in the capacitor sizes used (down to 400 nm diameter). Our work demonstrates that the determination of the actual capacitor structure and local electric field is needed to evaluate the intrinsic ferroelectric behavior at the nanoscale.
Incorporation of recombinant proteins into extracellular vesicles by Lactococcus cremoris
Abstract Extracellular vesicles (EVs) are nanosized lipid bilayer particles released by various cellular organisms that carry an array of bioactive molecules. EVs have diagnostic potential, as they play a role in intercellular interspecies communication, and could be applied in drug delivery. In contrast to mammalian cell-derived EVs, the study of EVs from bacteria, particularly Gram-positive bacteria, received less research attention. This study aimed to investigate the production of EVs by lactic acid bacterium Lactococcus cremoris NZ9000 and to examine the impact of recombinant protein expression on their formation and protein content. Four different recombinant proteins were expressed in L. cremoris NZ9000, in different forms of expression and combinations, and the produced EVs were isolated using the standard ultracentrifugation method. The presence of vesicular structures (50–200 nm) in the samples was confirmed by transmission electron microscopy and by flow cytometry using membrane-specific stain. Mass spectrometry analyses confirmed the presence of recombinant proteins in the EVs fraction, with amounts ranging from 13.17 to 100%, highlighting their significant incorporation into the vesicles, together with intrinsic L. cremoris NZ9000 proteins that were either more abundant in the cytoplasm (ribosomal proteins, metabolic enzymes) or present in the membrane. The presence of the most abundant lactococcal proteins in EVs fraction suggests that protein cargo-loading of EVs in L. cremoris NZ9000 is not regulated. However, our data suggests that L. cremoris NZ9000 genetically engineered to express recombinant proteins can produce EVs containing these proteins in scalable manner. As L. cremoris NZ9000 is considered safe bacterium, EVs from L. cremoris NZ9000 could have several advantages over EVs from other bacteria, implying possible biotechnological applications, e.g. in therapeutic protein delivery.
Magnon signatures of multidimensional reconfigurations in multilayer square artificial spin ices
We present an all-electrical, broadband spin-wave spectroscopy study of three-dimensional square artificial spin ices composed of dipolarly coupled ferromagnetic layers of varying thicknesses separated by a non-magnetic spacer. Our experiments, in the saturated regime, reveal that the spin-wave spectra exhibit a strong dependence on both the angle of the applied magnetic field and the geometrical aspect ratio of the ferromagnetic layers. Micromagnetic simulations and analytical calculations, utilizing the Smit–Beljers formalism, demonstrate good agreement with our experimental findings. In the magnetic switching regime, the spin-wave spectra indicate an antiparallel alignment between the two ferromagnetic layers. This configuration is highly sensitive to the field angle, suggesting the presence of multidimensional reconfigurations within the multilayer artificial spin ice. Furthermore, employing a minor loop field protocol, we show that the spin-wave modes associated with the antiparallel alignment remain reproducible, even after 100 minor loop cycles, providing intriguing possibilities for magnonic engineering.
A combinatory approach of non-chain ring and henon map for image encryption application
Design of spike-timing-dependent plasticity synapses based on CoPt-SOT device and its application in all-spin spiking neural network
Spintronic could be used to simulate synapses or neurons due to its multistate storage characteristics. In this work, a reliable design of all-spin spiking neural networks (SNN) based on spin–orbit torque (SOT) devices has been proposed in A1 CoPt single layer. The CoPt-SOT devices exhibited field-free SOT switching, and the magnetization reversal mechanism was inferred to be a combination of domain nucleation and domain-wall propagation as observed through magneto-optical Kerr microscopy images. Moreover, the current-induced SOT switching process of the device exhibited stable multistate magnetic switching behavior, which can be controlled by varying the amplitude and pulse width of the current pulse. Meanwhile, the spike-timing-dependent plasticity (STDP) curve was inverted when the SOT switching polarity was reversed by different magnetic fields, and the change in anomalous Hall resistances (ΔRH) in the STDP curve was linearly related to the SOT switching ratio. In addition, at the zero magnetic field, we constructed an all-spin SNN using STDP synapses and leaky integrate-and-fire neurons of CoPt-SOT devices. The handwritten digits recognition rate of this all-spin SNN network was 89.9%. These results substantiate that the CoPt single layer represents a promising hardware solution for high-performance neuromorphic computing, with applicability in the domain of SNN.
Application research of convolutional neural network and its optimization in lightning electric field waveform recognition
Highly selective aptasensor for optical detection of whole cell gastrointestinal pathogen <i>Shigella dysenteriae</i> at label-free liquid crystal–aqueous interface
This paper describes a label-free liquid crystal (LC)-based biosensor for a rapid and straightforward detection of whole cell Shigella dysenteriae at aqueous interfaces using a bacteria-specific aptamer. The stimuli-receptive properties of LCs induce a change in the orientational ordering of molecules at the LC–aqueous interface. This interfacial phenomenon has been utilized to record target binding interactions of the biosensor. The homeotropic LC alignment at the glass–LC and the aqueous–LC interfaces was obtained using the aligning agent dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride and the self-assembling property of the cationic surfactant cetyltrimethylammonium bromide, respectively. The introduction of the negatively charged Shigella aptamer causes the homeotropic molecules to morph to a planar/tilted ordering. Upon adding a small quantity of Shigella cells in liquid media, the aptamer–bacterium interaction causes a redistribution of the surfactant at the LC–aqueous interface, restoring the homeotropic alignment. This results in a bright-to-dark optical change observed under a polarizing optical microscope, thus implying the presence of the microbes. This reported aptasensor demonstrates high specificity, with the limit of detection being 30 CFU/ml within a linear range of 1–105 CFU/ml. To test the utility of this system, the sensor was also tested with close taxonomic relatives S. dysenteriae as well as real samples from the food chain. This proposed LC-based sensor offers several advantages over conventional detection techniques for a quick and convenient way for the detection of whole cell targets.
Therapeutic potential of brentuximab vedotin in breast cancer and lymphoma via targeted apoptosis and gene regulation
Abstract This study was designed to assess the effect of brentuximab vedotin on several breast cancer cell lines in terms of promoting apoptosis and managing cancer progression. Additionally, the study investigated the potential of repurposing this drug for new therapeutic reasons, beyond its original indications. The study evaluates the cytotoxic effects of Brentuximab vedotin across five cell lines: normal human skin fibroblasts (HSF), three breast cancer cell lines (MCF-7, MDA-MB-231, and T-47D), and histiocytic lymphoma (U-937). Brentuximab treatment was administered at four time points (0, 24, 48, and 72 h), with cell viability assessed at each interval. HSF cells, serving as controls, exhibited minimal viability loss (above 70%), indicating limited toxicity in normal fibroblasts. In contrast, MCF-7 and MDA-MB-231 cells demonstrated time-dependent reductions in viability, with a pronounced decline by 72 h, suggesting Brentuximab’s efficacy in both ER-positive and triple-negative breast cancer. T-47D cells also showed decreased viability, though at a slower rate. U-937 cells exhibited the most substantial reduction, highlighting Brentuximab’s potent activity against hematologic malignancies. Wound healing assays further revealed that Brentuximab significantly impaired the migration and healing capacity of cancer cells compared to untreated controls. Additionally, cell cycle analysis indicated G2/M phase arrest in cancer cells, particularly in MCF-7 and MDA-MB-231, while HSF cells remained largely unaffected. Apoptosis detection confirmed Brentuximab-induced cell death, with significant increases in late apoptosis in cancer lines, especially by 72 h. Gene expression analysis revealed upregulation of pro-apoptotic genes (BAX, Caspase 3, and Caspase 9) in cancer cells, alongside a decrease in anti-apoptotic BCL-2 expression. These findings suggest Brentuximab’s selective cytotoxicity against cancer cells and its potential as an effective therapeutic agent, particularly in breast cancer and histiocytic lymphoma.
Significant negative differential resistance and current limiting effects of cyclo[14]carbon-based molecular devices with graphene electrodes
Through tip-induced dehalogenation and retro-Bergman ring-opening reaction of fully chlorinated anthanthrene (C14Cl10), the cyclo[14]carbon (C14) was prepared. Owing to its distinctive physical properties, C14 holds the potential to serve as the core unit of functional electronic devices. Herein, the density functional theory combined with the non-equilibrium Green's function technique was used to investigate the electronic transport properties of molecular devices composed of C14 molecules and graphene electrodes, systematically. We find that molecular devices composed of polyynic and cumulenic structures of C14 exhibit a significant negative differential resistance effect and effective current limiting ability at low bias voltages, respectively. Moreover, by calculating and analyzing the transmission function and projected density of states under different biases, a reasonable explanation of those effects is provided.
From ideation to real context of use of a digital solution to promote physical and cognitive training for older adults
Realization and simulation of silicon-on-sapphire mid-infrared one-dimensional photonic crystal cavities
The mid-infrared (MIR) waveband is significant for chemical and biological sensing since it covers several atmospheric windows and molecular fingerprint regions. On-chip photonic integrated one-dimensional (1D) microcavities have great potential for high-performance mid-IR sensing because of their high sensitivity and compact structure. However, high-performance 1D microcavities based on the promising silicon-on-sapphire (SoS) MIR platform have not yet been designed or realized. Based on the photonic band structure induced by 1D photonic crystals (PhC), a high-performance Bragg reflector, an inward apodized Bragg grating, and a free spectral range (FSR)-free PhC microcavity integrated system operating in the MIR waveband were developed on the SoS platform. By carefully designing the period and penetration depth of the corrugation in the Bragg reflector, a stopband of 45 nm and an extinction ratio of −12 dB were achieved. The inward apodized Bragg grating was optimized by adjusting the apodization depth and the number of periods, resulting in a quality factor of 1043 at a wavelength of 3088.4 nm. Furthermore, introducing a Fabry–Pérot (F-P) cavity between two Bragg reflectors (with side-coupled light) and precisely tuning the stopband of the Bragg reflector and the FSR of the F-P cavity enabled the realization of an FSR-free PhC microcavity. This microcavity exhibited a single deep resonance dip with subnanometer bandwidth across a record-wide operational waveband from 3025 to 3200 nm, achieving a quality factor of approximately 5090. The MIR 1D PhC microcavities on the SoS platform hold great promise for high-performance gas detection and molecular sensing in future applications.
Age-related trends in trabecular bone scores and bone mineral density in Chinese men with type 2 diabetes mellitus: a cross-sectional study
Non-contact electroacoustic tomography with optical interferometer for electroporation therapy monitoring
Electroacoustic imaging is an imaging modality used to detect electric field energy distribution during electroporation, offering valuable guidance for clinical procedures, particularly in deep tissues. Traditionally, single-element piezoelectric transducers or arrays have been employed for this purpose. However, these piezoelectric sensors are sensitive to electromagnetic interference and require physical contact with the sample through a coupling medium, raising concerns for both clinical and preclinical applications. To overcome these limitations, a multi-channel random quadrature ultrasonics system has been developed, enabling non-contact detection of electroacoustic signals. In this study, we demonstrated that this non-contact technique effectively detects electroacoustic signals, identifies electroporation regions, and reconstructs electric energy distribution, offering a promising approach for monitoring electroporation therapy.
Spectroscopic aspects of underwater digital holography of plankton
Tailoring dynamics of thermally activated delayed fluorescence molecules embedded in cavity by forming coupling-induced hybrid states
Light–matter coupling-induced hybrid states provide the potential to tune the emission dynamics of molecular chromophores having multilevel systems. We demonstrate the alteration of delayed fluorescence dynamics by hybrid states formation through the interaction of light with a thermally activated delayed fluorescence molecule embedded in a conventional Fabry–Pérot cavity. The proximity of cavity resonance with the excited state absorption is modified by manipulating the incident angles (with sample) instead of varying the active layer thickness. The coupling-induced hybrid states are observed by angle-dependent emission spectroscopy and lifetime measurements. The variation in average emission lifetime with respect to incident angle is over 10 μs and is accompanied by significant changes in the full width at half maxima (factor of three). The control of emission via a barrier-free route or reverse intersystem crossing transition is demonstrated from these measurements. These findings suggest the possibility of tailoring intermediate states for lasing, where exciton density inversion can enhance spontaneous emission.