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Immune checkpoint inhibitors (ICIs) achieve a milestone in cancer treatment. Despite the great success of ICI, ICI therapy still faces a big challenge due to heterogeneity of tumor, and therapeutic response is complicated by possible immune-related adverse events (irAEs). Therefore, it is critical to assess the systemic immune response elicited by ICI therapy to guide subsequent treatment regimens. Positron emission tomography (PET) molecular imaging is an optimal approach in cancer diagnosis, treatment effect evaluation, follow-up, and prognosis prediction. PET imaging can monitor metabolic changes of immunocytes and specifically identify immuno-biomarkers to reflect systemic immune responses. Here, we briefly review the application of PET molecular imaging to date of systemic immune responses following ICI therapy and the associated rationale.

Alzheimer’s disease (AD) is the most common dementia worldwide. The exact etiology of AD is unclear as yet, and no effective treatments are currently available, making AD a tremendous burden posed on the whole society. As AD is a multifaceted and heterogeneous disease, and most biomarkers are dynamic in the course of AD, a range of biomarkers should be established to evaluate the severity and prognosis. Positron emission tomography (PET) offers a great opportunity to visualize AD from diverse perspectives by using radiolabeled agents involved in various pathophysiological processes; PET imaging technique helps to explore the pathomechanisms of AD comprehensively and find out the most appropriate biomarker in each AD phase, leading to a better evaluation of the disease. In this review, we discuss the application of PET in the course of AD and summarized radiolabeled compounds with favorable imaging characteristics.

Nanostructured mental-semiconductor-mental photodetectors (MSM-PDs) can assist in future high-speed communication devices for achieving high responsivity characteristics. However, such devices suffer from low responsivity due to low absorption, and the large band gap limits its detection range. Herein, we propose a GaAs-based photodetector with enhanced photoresponse by plasmonic Au-GaAs grating structure. The design of a grating structure on the surface of n-GaAs can excite a plasmon mode to enhance the photoelectric performance of photodetectors. Consequently, under 795 nm incident light irradiation, the grating hybrid detector exhibits a nearly 4.2-fold increase in photocurrent compared to the bare GaAs device. The enhanced absorption can be up to 99% and a specific responsivity of 240 mA/W is realized. These results can thus provide a potential scheme to fabricate high-performance GaAs detector for numerous applications.

A multi-exposures with dose modulation method is presented to fabricate SU-8 mold which is used for microfluidic channels. The method used a maskless digital lithography device with a 405 nm LED source. Digital micromirror device (DMD) maskless lithograph can reach higher precision to meet the requirements of microfluidic chips. For a thick SU-8 layer, multi-exposures with low dose method can effectively suppress the T-shaped structure formed due to top overexposed and bottom underexposed. Two SU-8 molds were fabricated with 55 μm and 25 μm in height in this work. The number of exposures is 62 and 55, respectively. The actual contour of SU-8 structures closely matches the design contour. The PDMS microchannel structure was fabricated using the SU-8 mold. The minimum width of a single microchannel achieved 10 μm. This method provides a more flexible method for fabricating SU-8 molds with higher precision and is well suited for on-chip cell isolation.

The projection lens is the core component of DMD-based maskless lithography and its imaging quality directly affects the transferal of exposure pattern. Based on the traditional projection lens system, we have designed diffractive optical element (DOE) and aspheric surfaces to optimize the refractive/diffractive hybrid projection lens system to improve its imaging quality. We found that the best effect is obtained when DOE is very close to the front lens group before the diaphragm of the hybrid system. Compared with the traditional projection lens system, this hybrid projection lens system has lower wave aberration with the help of DOE, and higher image quality owing to the modulation transfer function (MTF) value being improved. Finally, a hybrid projection lens system with working distance of 29.07 mm, image Space NA of 0.45, and total length of 196.97 mm is designed. We found that the maximum distortion and field curvature are 1.36 × 10−5% and 0.91 μm, respectively.

Aging is an inevitable process that all individuals experience, of which the extent differs among individuals. It has been recognized as the risk factor of neurodegenerative diseases by affecting gut microbiota compositions, microglia, and cognition abilities. Aging-induced changes in gut microbiota compositions have a critical role in orchestrating the morphology and functions of microglia through the gut-brain axis. Gut microbiota communicates with microglia by its secreted metabolites and neurotransmitters. This is highly associated with age-related cognitive declines. Here, we review the main composition of microbiota in the aged individuals, outline the changes of the brain in age-related cognitive decline from a neuroinflammation perspective, especially the changes of morphology and functions of microglia, discuss the crosstalk between microbiota and microglia in the aged brain and further highlight the role of microbiota-microglia connections in neurodegenerative diseases (Alzheimer's disease and Parkinson's disease).

A novel chip-scale metal-dielectric-metal (MDM) refractive-index sensor is proposed and investigated in this paper by using finite-difference time-domain (FDTD) method and multimode interference coupled-mode theory (MICMT), respectively. A slot cavity with an embedded tooth-shape cavity and a side-coupled semi-ring cavity are inserted between the input and output MDM waveguides. According to the simulation results, dual ultra-sharp and asymmetrical Fano peaks emerge in transmission spectrum with high performances. Besides, the transmission responses for the primary parameters of this structure are also investigated. To focus on developing integrated photonic devices, the original structure is successfully expanded by two additional semi-ring cavities through an innovative coupling approach, generating up to eight Fano peaks with outstanding characteristics. It is believed that this novel MDM structure will be a guideline for designing the chip-scale plasmonic devices.

Microstructures are fabricated with a fast fabrication speed, submicron-scale precision and a minimum feature size of 1.5 μm. The proposed rapid prototyping fabrication method takes advantage of the maskless lithography technique based on a digital mirror device (DMD) and photocurable resin, which has a broad range of uses in three-dimensional (3D) printing. To illustrate the feasibility of this method, a Dammann grating is fabricated. Using a series of experiments and optimized designs, we analyze the characteristics of the photocurable resin, quantify the dose modulation for lithography and redesign the mask pattern. Consequently, a Dammann grating with a 50% diffraction efficiency is successfully fabricated, which can not only guarantee the precision but also maintain the fabrication speed. This work demonstrates the potential of this method to rapidly and directly manufacture binary optical elements or structures at the nanoscale based on photocurable resin and DMD-based maskless lithography.

In this paper, we proposed polarization-dependent terahertz reflective beam splitters under normal incidence, in which resonance-domain diffraction gratings with period comparable to incident wavelength are adopted to achieve multi-channel beam separation, appropriate total diffraction efficiency, and good efficiency uniformity. At the frequency of 2.5200 THz (correspondingly the wavelength λ = 118.83 μm), the beam splitters can implement energy output varying from dual- to seven-port. For transverse electric (TE) polarization, the total efficiency of the beam splitters can reach ~ 95% (assuming the values 96.04%, 96.84%, 94.71%, 96.32%, 96.47%, and 95.08%, respectively, when the splitter’s output ports change from two to seven). For transverse magnetic (TM) polarization, under different structural parameters (namely the heights of the grating ridges h1 and h2) from TE polarization, the corresponding values are 96.62%, 95.23%, 92.81%, 93.11%, 92.99%, and 93.19%, respectively. Our results ( Table 2 ) demonstrate that all splitters, irrespective of the number of output ports, can provide appropriate total diffraction efficiency and good uniformity. Through rigorous coupled-wave analysis (RCWA), we derived the fabrication tolerance of the incident wavelength and period, which highlights the reliability of the proposed terahertz beam splitters.

In this paper, we investigate and analyze numerically and theoretically a coupled plasmonic resonant system by using finite-difference time-domain (FDTD) method and multimode interference coupled-mode theory (MICMT), respectively. First, by employing an end-coupled cavity associated with two side-coupled cavities, three ultra-sharp and asymmetrical Fano resonant peaks are observed in the transmission spectrum. High refractive index sensitivities and high figure of merits are achieved for all the peaks. In the interest of highly integrated optical devices, up to seven Fano peaks with asymmetrical line shapes are achieved when the composite structure is successfully extended by two additional cavities, whereas most of the reported results are about 1-4 Fano resonances in a single structure. Preferred performances are also obtained for this chip-scale structure. This proposed structure may have great potential applications for on-chip optical sensing and optical communication in highly integrated photonic circuits.

In this paper, multiple Fano resonances based on semi-ring-rectangular composite cavity (SRRCC) structure are numerically investigated and explained by the finite-difference time-domain method and the multiple interference coupled mode theory method. High refractive-index sensitivities and high figure of merits (FOMs) are obtained in SRRCC system, and thus it may be preferred in the chip-scale optical sensing area. Besides, the phase response and the delay time within the Fano resonant windows are also investigated. Additionally, two more Fano resonances with high sensitivities and FOMs emerge through adding a new semi-ring cavity. These structures show widely applications in the sensing area and promote development of on-chip integrated photonics.

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder associated with both genetic and environmental risks. Neuroimaging approaches have been widely employed to parse the neurophysiological mechanisms underlying ASD, and provide critical insights into the anatomical, functional, and neurochemical changes. We reviewed recent advances in neuroimaging studies that focused on ASD by using magnetic resonance imaging (MRI), positron emission tomography (PET), or single-positron emission tomography (SPECT). Longitudinal structural MRI has delineated an abnormal developmental trajectory of ASD that is associated with cascading neurobiological processes, and functional MRI has pointed to disrupted functional neural networks. Meanwhile, PET and SPECT imaging have revealed that metabolic and neurotransmitter abnormalities may contribute to shaping the aberrant neural circuits of ASD. Future large-scale, multi-center, multimodal investigations are essential to elucidate the neurophysiological underpinnings of ASD, and facilitate the development of novel diagnostic biomarkers and better-targeted therapy.

This paper designs a five-port transmission grating under normal incidence. Rigorous coupled-wave approach is used to optimize the grating parameters. The energy of the grating is mainly dispersed to the 0th, ±1st and ±2nd orders. The efficiency of each diffraction order under both polarizations is close to 20%. The modal method is used to describe the propagation mechanism of the two polarized lights in the grating, and the diffraction behavior of the grating is analyzed. In addition, the grating has a wide range of incident characteristics and a large process tolerance. Therefore, this five-port beam splitter with a connecting layer will be a good polarization-independent beam splitting device.

We propose a new kind of compound optical vortex (COV) generator in this paper. The device consists of an inner spiral phase plate (SPP) and an outer annular spiral phase plate. There is an opaque band between two SPPs. Under the flat-top beam irradiation, concentric multi-ring COV rings with different topological charges in different radial radii can be generated. The theoretical analysis lays a theoretical foundation for the design of the COV generator, and the simulation results prove the effectiveness of the design. The unique characteristics of COV are discussed and some of its potential application scenarios are presented. This work provides a design method for generating COV using compound SPPs, and the advanced COV structure can help to expand the scope of utilization of vortex beam in optical tweezers, optical communication and other fields.

Wearable fiber-shaped supercapacitor (SC) is a kind of one-dimensional flexible devices that can be directly knitted or sewn into various kinds of textile soft-substrate for wearable energy storage. Herein, acid-pretreated stainless steel yarn (SSY) has been developed to support electrodeposition of active materials of nickel/cobalt composite and polypyrrole (PPy) as the positive and negative electrodes, respectively. The asymmetric all-solid-state supercapacitors (AASs) showed both high electrochemical properties and excellent mechanical flexibility under various degrees of deformation. The highest volumetric capacitance reached 14.69 F cm−3 at the current density of 25 mA cm−3, and the maximum energy density was 3.83 mWh·cm−3 (0.032 mWh·cm−2) at a power density of 18.75 mW cm−3 (0.284 mW cm−2). The AASs were highly flexible and durable for directly being sewn into textile fabrics, and exhibited a good electrochemical stability under 6000 charging/discharging cycles. This work uses the common materials and facile methods to fabricate the flexible and wearable AASs with enhanced electrochemical properties, showing a decent way in developing flexible SC devices.

Through adding a groove to an end-coupled perfect ring (PR) resonator, a ring-groove (RG) joint metal-insulator-metal (MIM) structure is proposed. Destructive interference for the expected surface plasmon mode will occur due to the phase differences between two optical paths, leading to the plasmonic-induced absorption response with abnormal dispersion, which is analogous to the electromagnetically induced absorption in the three-level atomic system. A transmission dip is achieved at the former-peak wavelength of the PR resonator, while two transmission peaks arise around the window. The proposed structure, which benefits from -0.3 ps group delay time, will be preferred in the ultrafast-light applications. Due to the same interference effect, plasmonic-induced transparency response with slow-light characteristic is also investigated by arranging the RG joint resonator to be a side-coupled configuration. Therefore, a new approach for on-chip light-speed control can be developed by using the proposed structures, whose performances are investigated by the finite-difference time-domain (FDTD) method and the coupled mode theory.

On the basis of single metal-insulator-metal (MIM) ring resonator (RR) structure, which acts as a band-stopped filter, a dual RR (DRR) system is proposed to obtain the plasmon-induced transparency (PIT) effect. By rotating the second RR an angle, double PIT windows are achieved due to the dual interference effects, which are attributed to different excitation pathways from the first RR to the second RR. In addition, triple PIT peaks are also achieved by adding an extra inclined RR to the DRR system. Phase shifts, which will occur at each transparency window, are also achieved and analyzed. These compact MIM waveguide structures may be used in the highly integrated optical circuits for biochemical sensors optical signal processing, and optical data storage.

Truly knitted textiles based supercapacitors (SCs) are receiving great attention owing to their inherent flexibility and electrochemical performance. Here, the one-pot knitted conductive 3D spacer fabric (3DSF) was, for the first time, used as the frame supporting the highly pseudocapacitive materials. MnO2 and the electrochemically reduced graphene oxide (ErGO) are grown on the top and bottom layer of the 3DSF respectively, realizing a 3D all-textile asymmetric SC (3DAS) with a functional and structural integrity. Both water-proof and wear-resistant properties are readily rendered after encapsulating with the flexible multifunctional polyurethane (PU) film. A high specific capacitance of 1.02 F cm−2 (36.59 F g−1) is achieved at the current density of 7.5 mA cm−2 (0.275 A g−1), and the maximum areal energy density is nearly 1.02 mWh·cm−2 at a power density of 5.27 mW cm−2. The approach of coupling the advanced computerized technology with the chemical synthesis opens new avenues for the development of the truly flexible and wearable energy storage devices.

In this paper, we report on a type of SU-8 microstructure with vertical sidewalls used for polydimethydiloxane (PDMS) microchannels. Multi-layer lithography using focal plane changing approach is proposed to expose the SU-8 photoresist based on a digital micromirror device (DMD) maskless lithography system. We used a light-emitting diode source with a wavelength of 405 nm. The thickness of the SU-8 is divided into multi-layers according to the depth of focus. Each layer corresponds to a depth of focus, and then, a virtual mask is designed for the layer. Finally, each layer is exposed to changes in the focal plane. The results indicate that the actual profile of the SU-8 mold shows good agreement with the design profile without any T-profiles. Additionally, there is better linewidth in the proposed method compared with multi-exposure by a single fixed focal plane. The PDMS microchannels result also demonstrate the stability of the SU-8 mold.

In this study, a method is proposed for the rapid fabrication of a hexagonal compound eye microlens array (HCE-MLA) using maskless lithography technique based on digital micromirror device (DMD), in which a hexahedron array is lithographed, and subsequently, a microlens structure is lithographed layer by layer upon the hexahedron. Owing to the high filling rate of the hexagon and the aspheric surface of the paraboloid profile of the microlens, after the distribution of the required exposure dose of HCE-MLA was calculated based on dose modulation, a series of circular pattern with different radius could be obtained by equal-arc-mean slicing strategy that can adapt to the variable curvature of the target contour and improve its reconstruction precision. Then, after a hexagonal photoresist island was fabricated on the substrate, and the dose accumulated over multiple exposures, the required exposure dose profiles were reconstructed on the hexagonal photoresist island. Finally, a high-quality HCE-MLA with a smooth surface was fabricated via thermal reflow. The fabrication of the designed HCE-MLA using this method was demonstrated in experiments. The results indicate that the actual profile of HCE-MLA shows good agreement with the design profile and that simultaneously increasing the number of the slicing layers can improve the quality of the profile. The research indicated that this method is feasible and convenient for the fabrication of high-quality HCE-MLA.

In this paper, multiple Fano resonances preferred in the refractive index sensing area are achieved based on sub-wavelength metal-insulator-metal (MIM) waveguides. Two slot cavities, which are placed between or above the MIM waveguides, can support the bright modes or the dark modes, respectively. Owing to the mode interferences, dual Fano resonances with obvious asymmetrical spectral responses are achieved. High sensitivity and high figure of merit are investigated by using the finite-difference time-domain (FDTD) method. In view of the development of chip-scale integrated photonics, two extra slot cavities are successively added to the structure, and consequently, three and four ultra-sharp Fano peaks with considerable performances are obtained, respectively. It is believed that this proposed structure can find important applications in the on-chip optical sensing and optical communication areas.

A plasmonic end-coupled composite-square cavity (CSC) structure is proposed by adding two horizontal and normal slot cavities into a perfect square cavity (PSC) structure that is regarded as a Fabry-Perot resonator. Owing to the interference effect between the bright and dark modes, which is supported by the PSC and the slot cavities, respectively, a single plasmonic induced absorption (PIA) response with large abnormal dispersion is achieved at the former transmission peak in the CSC structure. The induced absorption window can be tuned to the wavelength of the first or second mode by using the horizontal and normal slot cavities. By changing the refractive index of the insulator inside the horizontal slot cavity, dual PIA responses are also obtained in the CSC structure. The performances of the proposed CSC structure are analyzed and investigated by using the finite-difference time-domain method.

An end-coupled composite-slot-cavity resonator (CSCR) is proposed based on the subwavelength metal-insulator-metal (MIM) waveguides. When compared with the perfect slot cavity, which acts as a Fabry–Perot resonator, plasmonic-induced absorption effect is achieved in the CSCR system. Single or dual absorption windows will arise at the former transmission peaks by arranging the position of vertical-slot cavity in the CSCR. According to the analyses on the phase responses, abnormal dispersions will be achieved inside the windows. Therefore, one can manipulate the fast-light applications in the nano-scale integrated circuits. Furthermore, based on the same interference effect, plasmonic-induced transparency response with normal dispersion is also obtained by changing the end-coupled CSCR system to a side-coupled one. The performances of the proposed structure are analyzed and investigated using the coupled mode theory and the finite-difference time-domain method, respectively.