Effects of silencing hsa_circ_0015326 on proliferation, migration, invasion, and apoptosis of epithelial ovarian cancer cells.

Although the treatment of ovarian cancer has made great progress, there are still many patients who are not timely detected and given targeted therapy due to unknown pathogenesis. Recent studies have found that hsa_circ_0015326 is upregulated in ovarian cancer and is involved in the proliferation, invasion, and migration of ovarian cancer cells. However, whether hsa_circ_0015326 can be used as a new target of ovarian cancer needs further investigation. Therefore, the effect of hsa_circ_0015326 on epithelial ovarian cancer was investigated in this study. At first, si-hsa_circ_0015326 lentivirus was transfected into epithelial ovarian cancer cells. Then real-time fluorescence quantitative PCR (qRT-PCR) was used to detect hsa_circ_0015326 level. The proliferation of ovarian cancer cells was detected by CCK-8 assay. The horizontal and vertical migration abilities of the cells were detected by wound-healing assay and Transwell assay, respectively. Transwell assay was also used to determine the invasion rate. As for the apoptosis rate, it was assessed by flow cytometry. As a result, the expression level of hsa_circ_0015326 in A2780 and SKOV3 was found to be higher than that in IOSE-80. However, after transfecting si-hsa_circ_0015326 and si-NC into the cells, the proliferation, migration, and invasion abilities of A2780 and SKOV3 cells in the si-hsa_circ_0015326 group were significantly reduced in comparison to those in the si-NC and mock groups, while their apoptosis rates were elevated. Collectively, silencing hsa_circ_0015326 bears the capability of inhibiting the proliferation, migration, and invasion of ovarian cancer cells while increasing apoptosis rate. It can be concluded that hsa_circ_0015326 promotes the malignant biological activities of epithelial ovarian cancer cells.

Testing region selection and prognostic analysis of MLH1 promoter methylation in colorectal cancer in China.

Background: MLH1 promoter methylation analysis is recommended in screening for Lynch syndrome (LS) in patients with MLH1-deficient colorectal cancer (CRC). The study aims to identify specific methylation regions in the MLH1 promoter and to evaluate the clinicopathologic characteristics of and prognosis for patients with MLH1 methylation. Methods: A total of 580 CRC cases were included. The DNA mismatch repair (MMR) protein expression was assessed by using immunohistochemistry (IHC). The methylation status of the Regions A, B, C, D, and E in the MLH1 promoter was tested by using bisulfite sequencing PCR. The specificities of the five regions were calculated. Associations between MLH1 methylation and clinicopathologic characteristics were evaluated. Kaplan-Meier analyses for overall survival (OS) were carried out. Results: In 580 CRC cases, the specificities of the methylation test in Regions D and E were both 97.8%. In the MLH1-deficient CRCs, the frequencies of MLH1 methylation and BRAFV600E mutation were 52.6% and 14.6%, respectively; BRAFV600E mutation occurred in 27.7% of patients with MLH1-methylated CRC. In the MMR-deficient patients, compared with MLH1 unmethylation, MLH1 methylation was more common in patients who were aged ≥50 years, female, had no family history of LS-related tumors, and had tumors located at the right colon. In the MMR-deficient patients, the MLH1-methylated cases had lower OS rates than the unmethylated cases with a family history of LS-related tumors (P = 0.047). Conclusions: Regions D and E in the MLH1 promoter are recommended for determining the MLH1 methylation status in screening for LS in MLH1-deficient CRC. In MMR-deficient patients, the MLH1-methylated cases had a worse OS than the unmethylated cases with a family history of LS-related cancer.

Analysis of factors associated with depressive symptoms in stroke patients based on a national cross-sectional study.

Post-stroke depression is commonly experienced by stroke survivors and has a significant negative impact on the physical, cognitive, and social functioning of those affected. This study aims to investigate the prevalence of depressive symptoms and their associated factors in Chinese stroke patients. Research samples were selected from the China Health and Retirement Longitudinal Study 2018 survey. Depression was evaluated using the 10-item Center for Epidemiological Studies Depression Scale, with a score ≥ 10 defined as depression. Univariate and multivariable analyses were performed to examine the associations of depressive symptoms with demographics, family relationships, health status, and lifestyle. A total of 963 stroke patients were included and 57.8% of them had depressive symptoms. Depressive symptoms were significantly associated with female sex (OR 1.762, 95% CI 1.235-2.514), lower education level (non-formal education: OR 2.148, 95% CI 1.235-3.737, primary to secondary school education: OR 1.964, 95% CI 1.272-3.033), dissatisfaction with spouse (OR 1.912, 95% CI 1.075-3.401), dissatisfaction with life (OR 1.779, 95% CI 1.080-2.931), dissatisfaction with health (OR 1.592, 95% CI 1.138-2.226), pain (OR 1.392, 95% CI 1.005-1.928) and abnormal sleep (OR 1.557, 95% CI 1.126-2.152). The findings suggest the need for regular depression screening and evaluation after a stroke, and that a well-functioning support system, effective health management, and lifestyle modifications could potentially improve the mental state of stroke patients.

Prognosis and immunotherapy efficacy in dMMR&MSS colorectal cancer patients and an MSI status predicting model.

The inconsistency between mismatch repair (MMR) protein immunohistochemistry (IHC) and microsatellite instability PCR (MSI-PCR) methods has been widely reported. We aim to investigate the prognosis and the effect of immunotherapy in dMMR by IHC but MSS by MSI-PCR (dMMR&MSS) colorectal cancer (CRC) patients. A microsatellite instability (MSI) predicting model was established to help find dMMR&MSS patients. MMR and MSI states were detected by the IHC and MSI-PCR in 1622 CRC patients (ZS6Y-1 cohort). Logistic regression analysis was used to screen clinical features to construct an MSI-predicting nomogram. We propose a new nomogram-based assay to find patients with dMMR&MSS, in which the MSI-PCR assay only detects dMMR patients with MSS predictive results. We applied the new strategy to a random cohort of 248 CRC patients (ZS6Y-2 cohort). The consistency of MMR IHC and MSI-PCR in the ZS6Y-1 cohort was 95.7% (1553/1622). Both pMMR&MSS and dMMR&MSS groups experienced significantly shorter overall survival (OS) than those in dMMR by IHC and MSI-H by MSI-PCR (dMMR&MSI-H) group (hazard ratio [HR] = 2.429, 95% confidence interval [CI]: 1.89-3.116, p < .01; HR = 21.96, 95% CI: 7.24-66.61, p < .01). The dMMR&MSS group experienced shorter OS than the pMMR&MSS group, but the difference did not reach significance (log rank test, p = .0686). In the immunotherapy group, the progression-free survival of dMMR&MSS patients was significantly shorter than that of dMMR&MSI-H patients (HR = 13.83, 95% CI: 1.508-126.8, p < .05). The ZS6Y-MSI-Pre nomogram (C-index = 0.816, 95% CI: 0.792-0.841, already online) found 66% (2/3) dMMR&MSS patients in the ZS6Y-2 cohort. There are significant differences in OS and immunotherapy effect between dMMR&MSI-H and dMMR&MSS patients. Our prediction model provides an economical way to screen dMMR&MSS patients.

An electron density clustering based adaptive segmentation method for protein Raman spectrum calculation.

Raman spectroscopy is a powerful technique for protein detection, but the calculation of Raman spectrum is a longstanding challenging problem due to the large sizes and complex structures of protein molecules. Dividing proteins into fragments can greatly accelerate the calculation, but this usually introduces large errors originating from ignored interactions between fragments into obtained spectra. In this paper, we proposed a new adaptive segmentation method based on the strength of interactions and molecular shapes and structures, i.e., electron density clustering, to divide proteins. It can reduce errors of obtained Raman spectra by about 20% compared to the uniform segmentation method without a significant increase in computational cost. This method can facilitate the validation and analysis of detected Raman spectra of proteins and promote the application of Raman spectroscopy in biological detection.

Head-to-head comparative study: evaluating three panels for MSI-PCR testing in patients with colorectal and gastric cancer.

AIMS: Due to the lack of large clinical cohorts in the Chinese populations with colorectal cancer (CRC) and gastric cancer (GC), there is no consensus among the preferred panel for microsatellite instability (MSI)-PCR testing. This study aims to evaluate a more appropriate panel. METHODS: We tested the MSI status of 2572 patients with CRC and GC using the NCI panel and 2 mononucleotide panels (5 and 6 mononucleotide panels). Immunohistochemistry (IHC) was employed to perform mismatch repair protein testing in 1976 samples. RESULTS: We collected 2572 patients with CRC and GC. The National Cancer Institute (NCI) panel failed to detect 13 cases. Of the 2559 cases that received results from all three panels, 2544 showed consistent results. In the remaining 15 cases, 9 showed discrepancies between MSI-H and MSI-L, and 6 showed discrepancies between MSI-L and microsatellite stability (MSS). The misdiagnosis rate of MSI-L was significantly lower in two mononucleotide panels than in the NCI panel (12.5% vs 87.5%, p=0.010) in CRC. In patients with GC, only the NCI panel detected three MSI-L cases, while the results of the two mononucleotide panels were one MSI-H and two MSS. Based on their IHC results, the MSI-L misdiagnosis rate of the NCI panel was 33.3%. Furthermore, compared with two mononucleotide panels, the NCI panel had a much lower rate of all loci instability in CRC (90.8% and 90.3% vs 25.2%) and GC (89.5% and 89.5% vs 12.0%). CONCLUSION: In Chinese patients with CRC and GC, the five and six mononucleotide panels have advantages for detecting MSI over the NCI panel.

Rapid Detection of SARS-CoV-2 in Clinical and Environmental Samples via a Resonant Cavity SERS Platform within 20 min.

The coronavirus disease 2019 (COVID-19) epidemic has given a warning that it is important to explore the rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in clinical specimens or environmental samples for public health strategies and future variants. The surface-enhanced Raman spectroscopy (SERS) technique was demonstrated to achieve this goal. However, the consistency of signals originating from the poor compatibility of virions with SERS hotspots remains a key scientific challenge for the practical applications of SERS. Herein, we develop a SERS platform for the ultrasensitive and rapid detection of SARS-CoV-2 antigen within 20 min by the combination of a highly consistent SERS substrate and a supervised deep learning algorithm. A V-shaped resonant cavity array (VRC) substrate was fabricated to trap SARS-CoV-2 virions in the periodic V cavity array and stimulate the integral SERS signal of the virus via a resonance coupling effect. Benefiting from the unique architecture of the VRC substrate, we were able to directly detect the SARS-CoV-2 virus with high sensitivity and high consistency. These excellent performances enabled us to identify five different kinds of SARS-CoV-2 variants and detect SARS-CoV-2 from clinical and environmental samples with high accuracies.

Application of essential oils as slow-release antimicrobial agents in food preservation: Preparation strategies, release mechanisms and application cases.

Food spoilage caused by foodborne microorganisms will not only cause significant economic losses, but also the toxins produced by some microorganisms will also pose a serious threat to human health. Essential oil (EOs) has significant antimicrobial activity, but its application in the field of food preservation is limited because of its volatile, insoluble in water and sensitive to light and heat. Therefore, in order to solve these problems effectively, this paper first analyzed the antibacterial effect of EOs as an antimicrobial agent on foodborne bacteria and its mechanism. Then, the application strategies of EOs as a sustained-release antimicrobial agent in food preservation were reviewed. On this basis, the release mechanism and application cases of EOs in different antibacterial composites were analyzed. The purpose of this paper is to provide technical support and solutions for the preparation of new antibacterial packaging materials based on plant active components to ensure food safety and reduce food waste.

Classification of Coronavirus Spike Proteins by Deep-Learning-Based Raman Spectroscopy and its Interpretative Analysis.

The outbreak of COVID-19 has spread worldwide, causing great damage to the global economy. Raman spectroscopy is expected to become a rapid and accurate method for the detection of coronavirus. A classification method of coronavirus spike proteins by Raman spectroscopy based on deep learning was implemented. A Raman spectra dataset of the spike proteins of five coronaviruses (including MERS-CoV, SARS-CoV, SARS-CoV-2, HCoVHKU1, and HCoV-OC43) was generated to establish the neural network model for classification. Even for rapidly acquired spectra with a low signal-to-noise ratio, the average accuracy exceeded 97%. An interpretive analysis of the classification results of the neural network was performed, which indicated that the differences in spectral characteristics captured by the neural network were consistent with the experimental analysis. The interpretative analysis method provided a valuable reference for identifying complex Raman spectra using deep-learning techniques. Our approach exhibited the potential to be applied in clinical practice to identify COVID-19 and other coronaviruses, and it can also be applied to other identification problems such as the identification of viruses or chemical agents, as well as in industrial areas such as oil and gas exploration.

Combined Morphological and Spectroscopic Diagnostic of HER2 Expression in Breast Cancer Tissues Based on Label-Free Surface-Enhanced Raman Scattering.

Breast cancer is the most commonly diagnosed cancer type worldwide. Overexpression of human epidermal growth factor receptor 2 (HER2) is an important subtype of breast cancer and results in an increased risk of recurrence and metastasis in patients. At present, immunohistochemistry (IHC) is used to detect the expression of HER2 in breast cancer tissues as the golden standard. However, IHC has some shortcomings, such as large subjective impact, long time consumption, expensive reagents, etc. In this paper, a combined morphological and spectroscopic diagnostic method based on label-free surface-enhanced Raman scattering (SERS) for HER2 expression in breast cancer is proposed. It can not only quantitively detect HER2 expression in breast cancer tissues by spectroscopic measurements but also give morphological images reflecting the distribution of HER2 in tissues. The results show that the consistency between this method and IHC is 95% and achieves the annotation of tumor regions on tissue sections. This method is time-consuming, quantifiable, intuitive, scalable, and easy to understand. Combined with deep learning approaches, it is expected to promote the development of clinical detection and diagnosis technology for breast cancer and other cancers.

Human amniotic mesenchymal stem cells promote endometrium regeneration in a rat model of intrauterine adhesion.

Human amniotic transplantation has been proposed to improve the therapeutic efficacy of intrauterine adhesions (IUAs). Human amniotic mesenchymal stem stromal cells (hAMSCs) can differentiate into multiple tissue types. This study aimed to investigate the mechanism by which hAMSCs transplantation promotes endometrial regeneration. The rat models with IUA were established through mechanical and infective methods, and PKH26-labeled hAMSCs were transplanted through the tail vein (combined with/without estrogen). Under three different conditions, hAMSCs differentiated into endometrium-like cells. HE and Mason staining assays, and immunohistochemistry were used to compare the changes in rat models treated with hAMSCs and/or estrogen transplantation. To define the induction of hAMSCs to endometrium-like cells in vitro, an induction medium (cytokines, estrogen) was used to investigate the differentiation of hAMSCs into endometrium-like cells. qRT-polymerase chain reaction (PCR) and western blotting were performed to detect the differentiation of hAMSCs into endometrium-like cells. A greater number of glands, fewer endometrial fibrotic areas, and stronger expression of vascular endothelial growth factor and cytokeratin in the combined group (hAMSCs transplantation combined with estrogen) than in the other treatment groups were observed. hAMSCs could be induced into endometrium-like cells by cytokine treatment (TGF-ß1, EGF, and PDGF-BB). Transplantation of hAMSCs is an effective alternative for endometrial regeneration after injury in rats. The differentiation protocol for hAMSCs will be useful for further studies on human endometrial regeneration.

Correlation coefficient-directed label-free characterization of native proteins by surface-enhanced Raman spectroscopy.

Investigation of proteins in their native state is the core of proteomics towards better understanding of their structures and functions. Surface-enhanced Raman spectroscopy (SERS) has shown its unique advantages in protein characterization with fingerprint information and high sensitivity, which makes it a promising tool for proteomics. It is still challenging to obtain SERS spectra of proteins in the native state and evaluate the native degree. Here, we constructed 3D physiological hotspots for a label-free dynamic SERS characterization of a native protein with iodide-modified 140 nm Au nanoparticles. We further introduced the correlation coefficient to quantitatively evaluate the variation of the native degree, whose quantitative nature allows us to explicitly investigate the Hofmeister effect on the protein structure. We realized the classification of a protein of SARS-CoV-2 variants in 15 min, which has not been achieved before. This study offers an effective tool for tracking the dynamic structure of proteins and biomedical research.

Autonomous Control of the Large-Angle Spacecraft Maneuvers in a Non-Cooperative Mission.

Aiming at the large-angle maneuver control problem of tracking spacecraft attitude in non-cooperative target rendezvous and proximity tasks, under the condition that the target spacecraft attitude information is unknown and the actuator output has physical limitations, a limited-time autonomous control method is proposed. First, an end-to-end pose estimation network is designed based on adaptive dual-channel feature extraction and dual attention. The information around the target is obtained through the adaptive dual-channel feature extraction module. The addition of spatial attention and channel attention allows the network to learn the target's characteristics more accurately. Secondly, based on the improved adaptive update law, a finite-time saturation controller is designed using the hyperbolic tangent function and the auxiliary system. The hyperbolic tangent function can strictly ensure that the control torque of the control system is bounded. Finally, the simulation results show that the proposed autonomous control method can accurately estimate the attitude of the non-cooperative target spacecraft and can maneuver to the target attitude within 20 s under the condition that the actuator's output is physically limited.

Ethanol Electrooxidation on an Island-Like Nanoporous Gold/Palladium Electrocatalyst in Alkaline Media: Electrocatalytic Properties and an In Situ Surface-Enhanced Raman Spectroscopy Study.

The design of electrocatalysts with high activity and the understanding of the reaction mechanism for the ethanol oxidation reaction (EOR) are pivotal for commercializing direct ethanol fuel cells (DEFCs). Herein, island-like nanoporous gold/palladium (INPG/Pd) is designed as a highly efficient EOR electrocatalyst. For a better understanding of the reaction mechanism, in situ surface-enhanced Raman spectroscopy (SERS) in conjunction with H-D isotope replacement is used to investigate the dissociation and oxidation of CH3CH2OH on the INPG/Pd electrode, with a focus on identifying significant intermediate species in the reaction process. The results show that INPG/Pd has a higher electrocatalytic performance than INPG and indium-tin oxide (ITO) glass/palladium (Pd) due to the synergistic effect of NPG and Pd. INPG/Pd-10 shows the highest specific activity, the strongest charge-transfer ability, and relatively good stability. INPG/Pd presents better SERS sensitivity than ITO glass/Pd because of the plasma enhancement effect of nanoporous Au. The in situ Raman spectral results suggest that the oxidation of ethanol proceeds via a dual-pathway (C1 and C2) reaction mechanism. Dehydrogenation of ethanol can form acetaldehyde (CH3CHO) at -0.4 V. Meanwhile, the adsorbed acetaldehyde is oxidized to acetate from approximately -0.4 V, with the potential moving positively, which is the so-called C2 pathway. Alternatively, in the C1 pathway, CH3CHO and CH3CH2OH decomposed to intermediate species (adsorbed CO) on the INPG/Pd electrode due to C-C bond breaking at potentials of approximately -0.2 V. Subsequently, the CO species is oxidized to CO2 at more positive potentials.

Antifungal mechanism of essential oil against foodborne fungi and its application in the preservation of baked food.

Baked food is one of the most important staple foods in people's life, but its shelf life is limited. In addition, the spoilage of baked food caused by microbial deterioration will not only cause huge economic losses, but also pose a serious threat to human health. At present, due to the improvement of consumers' health awareness, the use of chemical preservatives has been gradually restricted. Compared with other types of synthetic preservatives, essential oils are becoming more and more popular because they are in line with the current development trend of "green," "safety" and "health" of food additives. Therefore, in this paper, we first summarized the main factors affecting the fungal contamination of baked food. Then analyzed the antifungal activity and mechanism of essential oil. Finally, we comprehensively summarized the application strategy of essential oil in the preservation of baked food. This review is of great significance for fully understanding the antifungal mechanism of essential oils and promoting the application of essential oils in the preservation of baked food.

Identification and validation of PGLS as a metabolic target for early screening and prognostic monitoring of gastric cancer.

BACKGROUND: Gastric cancer is the third leading cause of cancer-related death in the world. The purpose of the present study is to investigate the expression and prognostic significance of 6-phosphogluconolactonase (PGLS) in gastric cancer. METHODS: The protein extracted from a panel of four pairs of gastric cancer tissues and adjacent tissues, labeled with iTRAQ (8-plex) reagents, and followed by LC-ESI-MS/MS. The expressions of proteins were further validated by immunohistochemistry analysis. The expression levels of mRNA were analyzed and validated in the Oncomine database. The correlations of PGLS with prognostic outcomes were evaluated with Kaplan-Meier plotter database. RESULTS: The present study found that PGLS was significantly up-regulated in gastric cancer by using iTRAQ-based proteomics and immunohistochemistry analysis. The sensitivity of PGLS in gastric cancer was 72.9%. The high expression of PGLS was significantly correlated with TNM staging in gastric cancer (p = 0.02). The overexpression of PGLS predicts worse overall survival (OS) and post-progression survival (PPS) for gastric cancer (OS, HR = 1.48, p = 2.1e-05; PPS, HR = 1.35, p = 0.015). Specifically, the high PGLS expression predicts poor OS, PPS in male gastric cancer patients, in patients with lymph node metastasis and in patients with Her-2 (-). CONCLUSIONS: These findings suggested that PGLS was aberrantly expressed in gastric cancer and predicts poor overall survival, post-progression survival for gastric cancer patients. The present study collectively supported that PGLS is an important target for early determining and follow-up monitoring for gastric cancer.

On-Site Detection of SARS-CoV-2 Antigen by Deep Learning-Based Surface-Enhanced Raman Spectroscopy and Its Biochemical Foundations.

A rapid, on-site, and accurate SARS-CoV-2 detection method is crucial for the prevention and control of the COVID-19 epidemic. However, such an ideal screening technology has not yet been developed for the diagnosis of SARS-CoV-2. Here, we have developed a deep learning-based surface-enhanced Raman spectroscopy technique for the sensitive, rapid, and on-site detection of the SARS-CoV-2 antigen in the throat swabs or sputum from 30 confirmed COVID-19 patients. A Raman database based on the spike protein of SARS-CoV-2 was established from experiments and theoretical calculations. The corresponding biochemical foundation for this method is also discussed. The deep learning model could predict the SARS-CoV-2 antigen with an identification accuracy of 87.7%. These results suggested that this method has great potential for the diagnosis, monitoring, and control of SARS-CoV-2 worldwide.

The Spectrum, Tendency and Predictive Value of PIK3CA Mutation in Chinese Colorectal Cancer Patients.

BACKGROUND: PIK3CA is a high-frequency mutation gene in colorectal cancer, while its prognostic value remains unclear. This study evaluated the mutation tendency, spectrum, prognosis power and predictive power in cetuximab treatment of PIK3CA in Chinese CRC cohort. METHODS: The PIK3CA exon 9 and 20 status of 5763 CRC patients was detected with Sanger sequencing and a high-resolution melting test. Clinicopathological characteristics of 5733 patients were analyzed. Kaplan-Meier method and nomogram were used to evaluate the overall survival curve and disease recurrence, respectively. RESULTS: Fifty-eight types of mutations in 13.4% (771/5733) of the patients were detected. From 2014 to 2018, the mutation rate of PIK3CA increased from 11.0% to 13.5%. At stage IV, exon 20 mutated patients suffered shorter overall survival time than wild-type patients (multivariate COX regression analysis, HR = 2.72, 95% CIs = 1.47-5.09; p-value = 0.012). At stage III, PIK3CA mutated patients were more likely to relapse (multivariate Logistic regression analysis, exon 9: OR = 2.54, 95% CI = 1.34-4.73, p = 0.003; exon 20: OR = 3.89, 95% CI = 1.66-9.10, p = 0.002). The concordance index of the nomogram for predicting the recurrence risk of stage III patients was 0.685. After cetuximab treatment, the median PFS of PIK3CA exon 9 wild-type patients (n = 9) and mutant patients (n = 5) did not reach a significant difference (3.6 months vs. 2.3 months, Log-rank test, p-value = 0.513). CONCLUSIONS: We found that PIK3CA mutation was an adverse predictive marker for the overall survival of stage IV patients and recurrence of stage III patients, respectively. Further more, we suggested that PIK3CA exon 9 mutations are not negative predictors of cetuximab treatment in KRAS, NRAS, and BRAF wild-type mCRC patients.

Toward the Limitation of Dealloying: Full Spectrum Responsive Ultralow Density Nanoporous Gold for Plasmonic Photocatalytic SERS.

Plasmon-mediated chemical reaction has a great potential to create self-cleaning surface-enhanced Raman scattering (SERS) substrates. However, few works have been reported to promote this goal. Here, we report ultralow density nanoporous gold (ULDNPG) that possesses an impressive full spectrum responsive characteristic with a reflectivity lower than 5% in the waveband of 300-900 nm. ULDNPG was fabricated by a sandwich dealloying strategy from ultradilute Au-Ag solid solutions with the Au content as low as 1-5 at.%. The prepared ULDNPG presents excellent SERS properties, including high sensitivity, high uniformity, and reproducibility. The full spectrum responsive characteristic of ULDNPG leads to an obvious plasmonic photocatalytic activity. The short lifetime of the SP-excited hot carriers causes a restricted self-cleaning SERS property and a strong photothermal effect for ULDNPG structures.

A 13-Bit, 12-ps Resolution Vernier Time-to-Digital Converter Based on Dual Delay-Rings for SPAD Image Sensor.

A three-dimensional (3D) image sensor based on Single-Photon Avalanche Diode (SPAD) requires a time-to-digital converter (TDC) with a wide dynamic range and fine resolution for precise depth calculation. In this paper, we propose a novel high-performance TDC for a SPAD image sensor. In our design, we first present a pulse-width self-restricted (PWSR) delay element that is capable of providing a steady delay to improve the time precision. Meanwhile, we employ the proposed PWSR delay element to construct a pair of 16-stages vernier delay-rings to effectively enlarge the dynamic range. Moreover, we propose a compact and fast arbiter using a fully symmetric topology to enhance the robustness of the TDC. To validate the performance of the proposed TDC, a prototype 13-bit TDC has been fabricated in the standard 0.18-µm complementary metal-oxide-semiconductor (CMOS) process. The core area is about 200 µm × 180 µm and the total power consumption is nearly 1.6 mW. The proposed TDC achieves a dynamic range of 92.1 ns and a time precision of 11.25 ps. The measured worst integral nonlinearity (INL) and differential nonlinearity (DNL) are respectively 0.65 least-significant-bit (LSB) and 0.38 LSB, and both of them are less than 1 LSB. The experimental results indicate that the proposed TDC is suitable for SPAD-based 3D imaging applications.