Capacitive Touch Panel with Low Sensitivity to Water Drop employing Mutual-coupling Electrical Field Shaping Technique

This paper proposes a novel method to reduce the water interference on the touch panel based on mutual-capacitance sensing in human finger detection. As the height of a finger (height >10 mm) is far larger than that of a water-drop (height 10 mm) and low in the low-height space (height <1 mm), the sensing cell can be designed to distinguish the finger from the water-drop. To achieve this density distribution of the electrical field, the mutual-coupling electrical field shaping (MEFS) technique is employed to build the sensing cell. The drawback of the MEFS sensing cell is large parasitic capacitance, which can be overcome by a readout IC with low sensitivity to parasitic capacitance. Experiments show that the output of the IC with the MEFS sensing cell is 1.11 V when the sensing cell is touched by the water-drop and 1.23 V when the sensing cell is touched by the finger, respectively. In contrast, the output of the IC with the traditional sensing cell is 1.32 and 1.33 V when the sensing cell is touched by the water-drop and the finger, respectively. This demonstrates that the MEFS sensing cell can better distinguish the finger from the water-drop than the traditional sensing cell does.National Research Foundation (NRF)Accepted versionThis work was supported in part by the National Natural Science Foundation of China (NSFC) under Grant 61771363, in part by the China Scholarship Council (CSC) under Grant 201706960042, and in part by the National Research Foundation of Singapore under Grant NRF-CRP11-2012-01

Self-assembled albumin nanoparticles induce pyroptosis for photodynamic/photothermal/immuno synergistic therapies in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is characterized by a high degree of malignancy, early metastasis, limited treatment, and poor prognosis. Immunotherapy, as a new and most promising treatment for cancer, has limited efficacy in TNBC because of the immunosuppressive tumor microenvironment (TME). Inducing pyroptosis and activating the cyclic guanosine monophosphate-adenosine monophosphate synthase/interferon gene stimulator (cGAS/STING) signaling pathway to upregulate innate immunity have become an emerging strategy for enhancing tumor immunotherapy. In this study, albumin nanospheres were constructed with photosensitizer-IR780 encapsulated in the core and cGAS–STING agonists/H2S producer-ZnS loaded on the shell (named IR780-ZnS@HSA). In vitro, IR780-ZnS@HSA produced photothermal therapy (PTT) and photodynamic therapy (PDT) effects. In addition, it stimulated immunogenic cell death (ICD) and activated pyroptosis in tumor cells via the caspase-3–GSDME signaling pathway. IR780-ZnS@HSA also activated the cGAS–STING signaling pathway. The two pathways synergistically boost immune response. In vivo, IR780-ZnS@HSA + laser significantly inhibited tumor growth in 4T1 tumor-bearing mice and triggered an immune response, improving the efficacy of the anti-APD-L1 antibody (aPD-L1). In conclusion, IR780-ZnS@HSA, as a novel inducer of pyroptosis, can significantly inhibit tumor growth and improve the efficacy of aPD-L1

SIRT1 Functions as an Important Regulator of Estrogen-Mediated Cardiomyocyte Protection in Angiotensin II-Induced Heart Hypertrophy

Background. Sirtuin 1 (SIRT1) is a member of the sirtuin family, which could activate cell survival machinery and has been shown to be protective in regulation of heart function. Here, we determined the mechanism by which SIRT1 regulates Angiotensin II- (AngII-) induced cardiac hypertrophy and injury in vivo and in vitro. Methods. We analyzed SIRT1 expression in the hearts of control and AngII-induced mouse hypertrophy. Female C57BL/6 mice were ovariectomized and pretreated with 17β-estradiol to measure SIRT1 expression. Protein synthesis, cardiomyocyte surface area analysis, qRT-PCR, TUNEL staining, and Western blot were performed on AngII-induced mouse heart hypertrophy samples and cultured neonatal rat ventricular myocytes (NRVMs) to investigate the function of SIRT1. Results. SIRT1 expression was slightly upregulated in AngII-induced mouse heart hypertrophy in vivo and in vitro, accompanied by elevated cardiomyocyte apoptosis. SIRT1 overexpression relieves AngII-induced cardiomyocyte hypertrophy and apoptosis. 17β-Estradiol was able to protect cardiomyocytes from AngII-induced injury with a profound upregulation of SIRT1 and activation of AMPK. Moreover, estrogen receptor inhibitor ICI 182,780 and SIRT1 inhibitor niacinamide could block SIRT1’s protective effect. Conclusions. These results indicate that SIRT1 functions as an important regulator of estrogen-mediated cardiomyocyte protection during AngII-induced heart hypertrophy and injury

Design of a high sensitivity and low power ultrasound receiver with a high-resolution SAR ADC for photoacoustic sensing and imaging

Photoacoustic (PA) imaging and sensing based on optical excitation and acoustic detection are emerging recently. The main issue of the PA systems is the poor SNR at the output of the sensors. The power consumption and size of the receiver are also crucial for the systems. Thus, several techniques are proposed in the analog front-end (AFE) and the analog-to-digital convertor (ADC) to improve the output SNR and power efficiency of the receiver. A resonant noise matching (RNM) technique is proposed to improve the sensitivity of ultrasound transducers. Diverse from the power matching which aims to maximize the output power from transducer in conventional electrical impedance matching (EIM) technique, the RNM maximizes the output voltage. The advantage of RNM is that it can also equivalently reduce the LNA’s input-referred noise and thus minimize the noise figure (NF) of the ultrasound receiver. Measurement results show that, the output signal is improved by 5 times through the proposed RNM technique, which is 66.7% larger than that of conventional methods. In addition, the sensitivity of the receiver is significantly improved by more than 10.4 dB which is beneficial for a variety of applications of piezoelectric ultrasound transducers. Thereafter, a high sensitivity and high dynamic range AFE is developed and fabricated in TSMC 65 nm CMOS process. An LNA with 30 dB gain and low input-referred noise (1 nV/Hz) is designed to amplify the input signal and suppress the noise from subsequent stages. Then a 3rd order Butterworth low-pass filter (LPF) with 5-20 MHz cut-off frequency is connected behind the LNA to reduce the out-of-band noise. Finally, a variable gain amplifier (VGA) which covers a gain range 0-45 dB with 20 MHz bandwidth are implemented in the AFE. The AFE is also applied in a photoacoustic sensor system which can achieve coherent lock-in function to detect weak PA signals noninvasively at in-vivo environments. An asynchronous SAR ADC with a novel mismatch error shaping (MES) technique is designed and fabricated. The power dissipation of the SAR ADC is dominated by the comparator, DAC and digital logic circuits. To reduce digital power consumption, the asynchronous timing sequence is adopted. As known, the resolution of SAR ADC is limited by the non-linearity of DAC and noise of comparator. The linearity of the DAC can be efficiently improved by the MES technique. The proposed novel MES technique can remove the flash ADC and DWA digital circuits in the convention MES technique, and thus improve the power efficiency. Noise shaping technique is also applied in the SAR ADC to reduce the comparator noise and improve the output SNR. In addition, another MES technique based on a double input range SAR ADC is also proposed. Through this method, the input signal is not necessary to be reduced by 2 times, which happens in the first proposed MES. Consequently, the output SNR can be improved by 3 dB. Overall, the main contributions of the thesis are: a) the RNM technique which is designed to improve the sensor’s sensitivity, b) A 0.18µVrms super-sensitivity photoacoustic imager based on coherent detection for deep in-vivo imaging and c) a low power and high-resolution SAR ADC with improved MES technique.Doctor of Philosoph

A high-speed 2-bit/cycle SAR ADC with time-domain quantization

This brief presents a 2-bit/cycle successive approximation register (SAR) analog-to-digital converter (ADC) with time-domain quantization, which only needs one capacitive digital-to-analog converter (DAC) array. A duplicated dynamic comparator is adopted to generate the time references. To quantize the time value, a dynamic latch-based high precision time-domain comparator is proposed. Moreover, a redundancy technique is utilized to overcome the effect of nonideal factors, such as incomplete DAC settling, reference scale mismatch, and offset of comparators. A design example of 9-bit 700 MS/s SAR ADC in 65-nm CMOS technology is presented. Simulation results show that with a differential 600-mVp-p input, the spurious free dynamic range at Nyquist input is above 65 dB. The simulated effective number of bit is up to 8.3 bits at 10-MHz input with the presence of noise and mismatches calibration

A photoacoustic-surface-acoustic-wave sensor for ring-stage malaria parasite detection

The detection of malaria parasite (plasmodium falciparum) is investigated by using a novel photoacoustics (PA) excited surface acoustic wave (SAW) sensor. The SAW sensor is designed to resonant around 10 MHz and is fabricated by using standard two-step photolithography. The photoacoustic PA-SAW sensing system is composed of a SAW sensor, cooperating with a pulsed laser, a neutral density filter, a convex lens, two analog front ends (AFEs) and an oscilloscope. PA signals and their spectrums of different materials are obtained for calibration, and the PA signals of normal blood and infected blood are chaterized through the PA-SAW sensing system, subsequently. The infected blood with cultured ring-stage malaria parasites concentrations of 1% can be detected. The demonstration shows that the PA-SAW sensor has good potential in the diagnosis of malaria at early stage.Nanyang Technological UniversityThis work was supported by the NTUHealth-LKCMedince-NHG under Grant IDPOCT17002

A 0.15μ Vrms super-sensitivity photoacoustic imager based on coherent detection for deep in-vivo imaging

Among various multi-wave imaging methods, the photoacoustic imaging (PAI) has attracted more attention because it can achieve higher resolution and contrast through combining advantages of light excitation and ultrasound detection. However, due to low restricted laser fluence, large scattering and attenuation in tissue, and low energy conversion efficiency, high sensitivity is still imperative in the receiver to read out PA signals. A new photoacoustic receiver with mixed-signal coherent detection technique is developed and fabricated for the first time. Co-working with the early-late acquisition and tracking technique, the receiver can lock into the weak PA signal automatically. For the receiver system on chip (SoC), a high performance analog front-end (AFE) with a low noise amplifier (LNA), low-pass filter (LPF), programmable-gain amplifier (PGA), multiplier, successive-approximation analog-to-digital converter (SAR ADC) and digital-to-analog converter (DAC) are implemented on chip. Noise shaping (NS) technique is implemented in the SAR ADC to enhance the signal-to-noise ratio (SNR). Measurement results show that, the LNA achieves 0.23mPa√(mW/Hz) noise efficiency factor (NEF) with the aid of resonant noise matching (RNM) technique, and the NS-SAR ADC can obtain 62.2dB signal-to-noise-and-distortion ratio (SNDR) in 10MHz bandwidth under 100MS/s sampling rate. The single channel receiver can achieve 135dB dynamic range and 0.15μ Vrms sensitivity. The output SNR can be improved by about 6dB after enabling the 4 channels. The power consumption of a single channel is 28.8mW. The contrast-to-noise ratio (CNR) of the images at 1cm depth is 44dB.Ministry of Education (MOE)Published versionThis work was supported by the Singapore Ministry of Education (MOE) under Grant of AcRF Tier 2: MOE2019-T2-2-179

External partial discharge detection of gas-insulated switchgears using a low-noise and enhanced-sensitivity UHF sensor module

Ultrahigh frequency (UHF) partial discharge (PD) detection is essential for routine maintenance of gas-insulated switchgear (GIS). Realizing low-noise detection with cost-effectiveness and ease of installation is promising but challenging. This article presents a novel broadband noise-shaping network (BNSN) integrated with a printed monopole antenna (PMA) sensor to realize sufficient noise rejection and good impedance matching. Moreover, by analyzing the equivalent noise circuit and co-designing a high-speed preamplifier circuit with the proposed sensor, the detection sensitivity and anti-interference of the proposed sensor module are improved. The effectiveness and superiority of the proposed sensor are first verified in accordance with IEC 62478, followed by validations using a PD simulator and a real 24-kV GIS. The experimental results demonstrate that the proposed sensor module has the capability to identify different PD types even in noisy environments.Energy Market Authority (EMA)Nanyang Technological UniversityNational Research Foundation (NRF)This work was supported in part by the SP Group; in part by the National Research Foundation, Singapore; in part by the Energy Market Authority, under its Energy Program (EP) under Award EMA-EP010-SNJL-004; in part by the Nanyang Technological University; and in part by the National Natural Science Foundation of China under Grant 62101104