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DNA inverted repeats (IRs) are widespread across many eukaryotic genomes. Their ability to form stable hairpin/cruciform secondary structures is causative in triggering chromosome instability leading to several human diseases. Distance and sequence divergence between IRs are inversely correlated with their ability to induce gross chromosomal rearrangements (GCRs) because of a lesser probability of secondary structure formation and chromosomal breakage. In this study, we demonstrate that structural parameters that normally constrain the instability of IRs are overcome when the repeats interact in single-stranded DNA (ssDNA). We established a system in budding yeast whereby >73 kb of ssDNA can be formed in cdc13-707fs mutants. We found that in ssDNA, 12 bp or 30 kb spaced Alu-IRs show similarly high levels of GCRs, while heterology only beyond 25% suppresses IR-induced instability. Mechanistically, rearrangements arise after cis-interaction of IRs leading to a DNA fold-back and the formation of a dicentric chromosome, which requires Rad52/Rad59 for IR annealing as well as Rad1-Rad10, Slx4, Msh2/Msh3 and Saw1 proteins for nonhomologous tail removal. Importantly, using structural characteristics rendering IRs permissive to DNA fold-back in yeast, we found that ssDNA regions mapped in cancer genomes contain a substantial number of potentially interacting and unstable IRs.

The synthesis capabilities of the translation system (TS) provide engineering and directed evolution potential as well as a system for generating novel polymers. Orthogonal translation systems offer a parallel platform for translation engineering, enabling primary and secondary translation systems to operate independently without interfering with each other. However, current translation platforms for engineering lack complete orthogonality between the primary and secondary systems. Using a combination of indirect modifications through antibiotics, truncations of mito-rProteins mL50 and uL23, and replacement of mito-rProtein uL2, we develop and test the mitochondrial translation system inSaccharomyces cerevisiaeas a fully orthogonal platform forin vivodirected evolution of translation. Our results show that continuous, comprehensive, creative, directed-evolution of a fully orthogonal TSin vivoappears to be a useful approach for technical control of the TS. This study emphasizes the power of system-wide evolutionary approaches over rational design. Evolution is creative and non-linear and can find unexpected solutions to problems.SignificanceAll life operates on the central dogma, information flows from DNA to mRNA to protein. The translation system decodes mRNA and produces proteins. Engineering and evolving the translation system permits full technical control over this process and could lead to the generation of novel polymers. Here we explore the mitochondrial translation system in the budding yeastSaccharomyces cerevisiaefor directed evolution of translation. We modify and evolve the translation system both directly and indirectly using antibiotics and gene editing tools and then measure resulting functionality. Our results show this secondary translation system insideS. cerevisiaemitochondria can be used as an approach for translation engineering.

Hua Ye,1 Mengxia Sun,2 Shiliang Huang,1 Feng Xu,1 Jian Wang,3 Huiwei Liu,1 Liangshun Zhang,1 Wenjing Luo,1 Wenying Guo,1 Zhe Wu,1 Jie Zhu,4 Hong Li4 1Department of Gastroenterology, Ningbo Medical Treatment Center Lihuili Hospital, Medical School of Ningbo University, Ningbo, Zhejiang, 315040, People’s Republic of China; 2Department of Clinical Medicine, Medical School of Ningbo University, Ningbo, Zhejiang, 315211, People’s Republic of China; 3Department of Dermatology, Ningbo Medical Treatment Center Lihuili Hospital, Medical School of Ningbo University, Ningbo, Zhejiang, 315040, People’s Republic of China; 4Department of Hepatobiliary Surgery, Ningbo Medical Treatment Center Lihuili Hospital, Medical School of Ningbo University, Ningbo, Zhejiang, 315040, People’s Republic of ChinaCorrespondence: Hua YeDepartment of Gastroenterology, Ningbo Medical Treatment Center Lihuili Hospital, Medical School of Ningbo University, Ningbo, Zhejiang, 315040, People’s Republic of ChinaTel/Fax +86 57483023687Email yh-med@163.comHong LiDepartment of Hepatobiliary Surgery, Ningbo Medical Treatment Center Lihuili Hospital, Medical School of Ningbo University, Ningbo, Zhejiang, 315040, People’s Republic of ChinaEmail lancet2017@163.comBackground: Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality worldwide. HCC transcriptome has been extensively studied; however, the progress in disease mechanisms, prognosis, and treatment is still slow.Methods: A rank-based module-centric workflow was introduced to analyze important modules associated with HCC development, prognosis, and drug resistance. The currently largest HCC cell line RNA-Seq dataset from the LIMORE database was used to construct the reference modules by weighted gene co-expression network analysis.Results: Thirteen reference modules were identified with validated reproducibility. These modules were all associated with specific biological functions. Differentially expressed module analysis revealed the crucial modules during HCC development. Modules and hub genes are indicative of patient survival. Modules can differentiate patients in different HCC stages. Furthermore, drug resistance was revealed by drug-module association analysis. Based on differentially expressed modules and hub genes, six candidate drugs were screened. The hub genes of those modules merit further investigation.Conclusion: We proposed a reference module-based analysis of the HCC transcriptome. The identified modules are associated with HCC development, survival, and drug resistance. M3 and M6 may play important roles during HCV to HCC development. M1, M3, M5, and M7 are associated with HCC survival. High M4, high M9, low M1, and low M3 may be associated with dasatinib, doxorubicin, CD532, and simvastatin resistance. Our analysis provides useful information for HCC diagnosis and treatment.Keywords: HCV, IC50, microarray, module preservation, WGCNA

Flavonoids are secondary metabolites that are widely distributed in plants with numerous biological functions. This study focused on Liquidambar formosana, a tree species rich in flavonoids that are used for ornamental and medicinal purposes. To better understand the chemical processes leading to seasonal variation in leaf color in L. formosana ‘Nanlinhong,’ we selected four colors of leaves in three seasons from the same individual trees, bright red in early spring, red in middle spring, green in summer, and dark red in autumn. The three-year-old trees of this variety were grown in the greenhouse under natural light with day and night temperatures from 30 to 23 ℃, and fully expanded leaves from the top of each individual were employed in flavonoid analyses. The results showed that the total flavonoid content was highest in spring, while anthocyanidin content was highest in autumn leaves. A total of 148 flavonoid metabolites were found using the Ultra-Performance Liquid Chromatography–Electrospray Ionization–Tandem Mass Spectrometry (UPLC-ESI–MS/MS) method; the compounds comprised 58 flavones, 33 flavonols, 18 flavanones, 16 polyphenols, 15 anthocyanins, six isoflavones, and two proanthocyanins. Through clustering analysis, a total of 122 types of metabolites were found in spring with higher expression levels, and 104 metabolites were found in autumn, indicating that flavonoids were more predominant in spring. To date, only 23 flavonoid compounds had been identified in this tree species, but the present study revealed 100 new compounds. In addition, our findings provide strong support for a differentiated use of L. formosana ‘‘s leaves from different seasons in targeting a wide range of medical conditions.

Objectives: This study evaluated the feasibility and safety of zone 1 thoracic endovascular aortic repair (TEVAR) with fenestrated surgeon-modified stent-graft (SMSG) for aortic arch pathologies. Methods: Between March 2016 and November 2020, 34 consecutive patients underwent zone 1 TEVAR with fenestrated SMSG for aortic arch pathologies. Outcomes included technical success, perioperative, and follow-up morbidity and mortality. Results: During the study period, 34 patients were treated with zone 1 TEVAR with fenestrated SMSG. Twenty-four (70.6%) patients presented with type B aortic dissections, 9 (26.5%) patients presented with aneurysms (7 located on the lesser curvature side of aortic arch), 1 (2.9%) patient presented with type Ia endoleak after previous TEVAR owing to traumatic aortic dissection. The proximal landing zone for all patients were in zone 1, and all supra-aortic trunks were reconstructed, except for one left subclavian artery. Technical success was achieved in all cases. The 30-day estimated survival (±SE) was 90.9% ± 5.0% [95% confidence interval (CI): 77.0%–97.0%]. The 30-day estimated freedom from reintervention (±SE) was 87.9% ± 5.7% (95% CI: 73.4%–95.3%). At a median follow-up of 48 months (range, 12–68 months), 2 patients died, including 1 aortic-related death and 1 non-aortic-related death. One patient had reintervention 13 months after the operation owing to type Ia endoleak. All supra-aortic trunks were patent. The estimated survival (±SE) during follow-up was 85.1% ± 6.2% (95% CI: 69.9%–93.6%). One (2.7%) patient had stroke. The estimated freedom from reintervention (±SE) during follow-up was 84.2% ± 6.5% (95% CI: 69.9%–93.5%). Conclusions: Zone 1 TEVAR with fenestrated SMSG is an alternate option for treatment of aortic arch pathologies in experienced centers.

Palindromic sequences are a potent source of chromosomal instability in many organisms and are implicated in the pathogenesis of human diseases. In this study, we investigate which nucleases are responsible for cleavage of the hairpin and cruciform structures and generation of double-strand breaks at inverted repeats in Saccharomyces cerevisiae. We demonstrate that the involvement of structure-specific nucleases in palindrome fragility depends on the distance between inverted repeats and their transcriptional status. The attack by the Mre11 complex is constrained to hairpins with loops

DNA double-stranded breaks (DSBs) trigger human genome instability, therefore identifying what factors contribute to DSB induction is critical for our understanding of human disease etiology. Using an unbiased, genome-wide approach, we found that genomic regions with the ability to form highly stable DNA secondary structures are enriched for endogenous DSBs in human cells. Human genomic regions predicted to form non-B-form DNA induced gross chromosomal rearrangements in yeast and displayed high indel frequency in human genomes. The extent of instability in both analyses is in concordance with the structure forming ability of these regions. We also observed an enrichment of DNA secondary structure-prone sites overlapping transcription start sites (TSSs) and CCCTC-binding factor (CTCF) binding sites, and uncovered an increase in DSBs at highly stable DNA secondary structure regions, in response to etoposide, an inhibitor of topoisomerase II (TOP2) re-ligation activity. Importantly, we found that TOP2 deficiency in both yeast and human leads to a significant reduction in DSBs at structure-prone loci, and that sites of TOP2 cleavage have a greater ability to form highly stable DNA secondary structures. This study reveals a direct role for TOP2 in generating secondary structure-mediated DNA fragility, advancing our understanding of mechanisms underlying human genome instability.

Background: Liriodendron chinense ranges widely in subtropical China and northern Vietnam; however, it inhabits several small, isolated populations and is now an endangered species due to its limited seed production. The objective of this study was to develop a set of nuclear SSR (simple sequence repeats) and multiple chloroplast genome markers for genetic studies in L. chinense and their characterization in diverse germplasm. Results: We performed low-coverage whole genome sequencing of the L. chinense from four genotypes, assembled the chloroplast genome and identified nuclear SSR loci by searching in contigs for SSR motifs. Comparative analysis of the four chloroplast genomes of L. chinense revealed 45 SNPs, 17 indels, 49 polymorphic SSR loci, and five small inversions. Most chloroplast intraspecific polymorphisms were located in the interspaces of single-copy regions. In total, 6147 SSR markers were isolated from low-coverage whole genome sequences. The most common SSR motifs were dinucleotide (70.09%), followed by trinucleotide motifs (23.10%). The motif AG/TC (33.51%) was the most abundant, followed by TC/AG (25.53%). A set of 13 SSR primer combinations were tested for amplification and their ability to detect polymorphisms in a set of 109 L. chinense individuals, representing distinct varieties or germplasm. The number of alleles per locus ranged from 8 to 28 with an average of 21 alleles. The expected heterozygosity (He) varied from 0.19 to 0.93 and the observed heterozygosity (Ho) ranged from 0.11 to 0.79. Conclusions: The genetic resources characterized and tested in this study provide a valuable tool to detect polymorphisms in L. chinense for future genetic studies and breeding programs.

In this study, a strategy was developed to directly recover high-purity Ag and other metals (especially Cu) from WECs to reduce the leaching of precious metals and promote the leaching of Cu and other metals. The results of SEM, EDS, XRD and ICP-OES clearly suggested that Ag and Cu were effectively released from WECs below 0.15 mm size, which contributed to the regulation of metals crystal types. The zero-valent copper from WECs was changed by roasting to form CuO and Cu2O, and the suitable samples of roasting at 400 °C for 3 h were confirmed experimentally. After the leaching processing under H2SO4 (1 M) and H2O2 (30%), the roasted particles were directly obtained, including Ag with 99.53 wt.% purity and more than 99.99% recovered, and Cu, Sn, Ni and Zn extracted by 99.67%, 90.71%, 73.05% and 99.32%, respectively. However, the unroasted particles would generate lower grade of Ag because other metals (e.g. Cu, Sn, Ni and Zn) were difficult to be leached from WECs. The leaching solution primarily included Cu ions (98.3%) and a little of the nickel (0.83%) and tin (0.86%) ions, which could recover copper by evaporation crystallization to form CuSO4 (99.48 wt. %). The reaction mechanism of the process could be concluded that the copper state was transformed by mechanical separation and roasting to promote the leaching of various metals from Ag.

Network alignment plays a significant role in network analysis and benefits a wide range of applications. However, existing methods are sensitive to structural noises and do not consider the one-to-one constraint on the anchor links. In this paper, to tackle this problem, we propose a novel framework called embedding-based network Alignment using Neural Tensor Networks (AlignNTN). It considers the one-to-one constraint and uses the neural tensor networks to learn the relationship between nodes in two networks. The proposed method provides a powerful way to learn the relationship between nodes and does not necessarily rely on demographic features. What is more, our model can easily incorporate with node attributes to improve the effectiveness of network alignment. Extensive experiments have been conducted on four real-world datasets, and the results demonstrate that the proposed method outperforms state-of-the-art methods by a significant margin.

Stance classification in tweet aims at detecting whether the author of the tweet is in FAVOR of, AGAINST, or NONE towards a pre-chosen target entity. Recently proposed Densely Connected BI-LSTM can effectively relieve overfitting and vanishing-gradient problems as well as dealing with long-term dependencies during multi-layer LSTM training. Based on this, we propose a two-stage deep attention neural network(T-DAN) for target-specific stance detection. This model employs densely connected BI-LSTM to encode tweet tokens and traditional bidirectional LSTM to encode target tokens. Besides, we decompose this ternary classification problem into two binary classification problems to mitigating the imbalanced distribution of labels. In the first stage, we find out the tweet is neutral or subjective about the specific target. In the second stage, we classify the stance of a given subjective tweet’s stance. Moreover, we propose a novel method of attention calculation based on the semantic similarity of tweet tokens and target tokens which can locate the crucial words related to target. Experimental results on English and Chinese datasets demonstrate that our proposed method surpasses some strong baselines and achieves the stateof-the-art performance.

Pre-trained language model can express the semantics of word or text span, is widely applied in many NLP tasks, and text summarization is no exception. It is created using fine-tuning or feature-based method on pre-training model. Since Bidirectional Encoder Representations from Transformers (BERT; Devlin et al. 2019), many works model text summarization based on BERT, and fine tune all the parameters end-to-end. Notably, multiple research proposed different strategies to create enhanced versions of BERT further, which achieve the state-of-the-art performance in many NLP tasks. In this paper, we explore the potential of multiple versions of BERT to handle text summarization. We present a two-stage encoder model (TSEM) for extractive summarization. The first stage applies A Lite BERT (ALBERT; Lan et al. 2019) to secure sentence-level embedding, identify valuable content based on A Lite BERT (ALBERT; Lan et al. 2019). The second stage proposes a new strategy to fine-tune BERT deriving meaningful document embedding, then select the best-matched combination of important sentences with source document to compose summarization. Experimental result on the CNN/Daily Mail dataset demonstrates that our model is competitive with the state-of-the-art result.

Combining chemotherapy with immunotherapy improves the therapeutic outcome for first-line (1L) patients with advance nonsmall-cell lung cancer (NSCLC). Two cohorts of a phase 1b study (NCT02937116) aimed to evaluate the safety and efficacy of sintilimab, a PD-1 inhibitor, plus chemotherapy in 1L patients with nonsquamous and squamous NSCLC (nsqNSCLC/sqNSCLC); and to identify potential biomarkers for treatment response. Treatment-naïve patients with nsqNSCLC were enrolled and intravenously given sintilimab (200 mg), pemetrexed (500 mg/m2), and cisplatin (75 mg/m2), every 3 weeks (Q3W) for 4 cycles in cohort D. Treatment-naïve patients with sqNSCLC were enrolled and intravenously given sintilimab (200 mg), gemcitabine (1250 mg/m2), and cisplatin (75 mg/m2), Q3W, for 6 cycles in cohort E. The primary objective was to evaluate the safety and efficacy of the treatment. The additional objective was to explore biomarkers for the treatment efficacy. Twenty-one patients with nsqNSCLC, and 20 patients with sqNSCLC were enrolled in cohort D and cohort E, respectively. By the data cutoff (April 17, 2019), 8 (38.1%) patients in cohort D and 17 (85.0%) patients in cohort E experienced grade 3–4 adverse events. The median follow-up duration was 16.4 months (14.8–23.0) in cohort D and 15.9 months (11.7–17.7) in cohort E. The objective response rate was 68.4% (95% CI 43.4%, 87.4%) in cohort D and 64.7% (95% CI 38.3%, 85.8%) in cohort E. Neither PD-L1 expression nor tumor mutation burden value was significantly associated with an improved treatment response. Sintilimab plus chemotherapy exhibited manageable toxicity and an encouraging antitumor activity in patients with nsqNSCLC and sqNSCLC. Electronic supplementary material The online version of this article (10.1007/s00262-020-02738-x) contains supplementary material, which is available to authorized users.

The utilization of nano zero valent iron is recognized as a potential approach for debromination of Tetrabromobisphenol A (TBBPA). In this study, Pycnoporus sanguineus cells were employed for biosupported Au nano particles (bio-AuNPs) preparation, then calcinated for obtaining porous carbon doped with Au nano particles (Au@biocarbon) and generated Au@biocarbon supported zero-valent iron nanoparticles (Au/Fe@biocarbon). The role of Au/Fe@biocarbon during debromination was evaluated by comparing with Au@biocarbon, biocarbon and Fe@biocarbon. Results showed that Fe 0 and Au 0 are successfully loaded on the surface of porous biocarbon with well-dispersion and higher specific surface area. The removal and debromination efficiency of TBBPA driven by Au/Fe@biocarbon was up to about 99.85% and 97.18% within 100 min, respectively. Higher dosage and acidic condition were more beneficial to removal of TBBPA with the most appropriated Au/Fe molar ratio of 2%, where the complete removal of TBBPA only took 20 min. The mechanism of TBBPA debromination by Au/Fe@biocarbon was the joint function of adsorption of biocarbon and galvanic cell of biosupported Au/Fe bimetals. Therefore, Au/Fe@biocarbon could be an alternative to effectively boost rapid and complete debromination of TBBPA.

Gold nanoparticles (GNPs) were deposited directly onto the surface of indium tin oxide (ITO) thin film-coated glass by electrochemical method. It was used as a photoanode in a photoelectrochemical (PEC) cell for sensitive detection of hydroquinone (HQ) at an applied bias potential of 0.15 V vs. saturated calomel electrode. This heterostructure showed dramatically enhanced PEC properties due to the introduction of the Au/ITO interface. Under the irradiation, the marked photocurrent response was observed at the GNPs/ITO photoelectrode compared with bare ITO electrode. The anodic photocurrent could be further largely enhanced by HQ. A new PEC strategy for sensitive detection of HQ at a relative low potential was developed. The linear range for HQ determination was 0.25 to 150 μM, with a detection limit of 0.1 μM. The sensitivity on the GNPs/ITO electrode at the irradiation was ~ 3.3 times higher than that in dark. These results demonstrate that the simple GNPs/ITO electrodes have great potential for PEC analysis application.

Novel NaBi(MoO4)2 nanorods were synthesized facilely by a one-step solvothermal method. The results showed the NaBi(MoO4)2 nanorods were composed of nanoparticles in linear arrangement. The mean crystal size of the NaBi(MoO4)2 nanoparticles was of 18.8 nm. The sensor based on NaBi(MoO4)2 nanorods exhibited good gas-sensing properties towards alcohols especially n-butanol. The highest sensitivity to 100 ppm n-butanol was 30 at the optimal operating temperature of 370 °C without cross response to acetone, xylene and toluene. The sensor is a promising candidate for fast, sensitive and selective detection of n-butanol.

Instability of trinucleotide and inverted repeats is a causative factor in the development of a number of neurological diseases, hereditary syndromes, and cancer. To understand the mechanisms that lead to repeat-induced genome destabilization it is important to identify factors that affect repeat metabolism. Here we present an approach that utilizes systematic and unbiased genome-wide screen in yeast Saccharomyces cerevisiae aimed to find genes that govern GAA/TTC and inverted repeat instability. These screens allowed for the identification of more than 30 mutants with increased fragility of both repeat motifs.

Sound from different spatial directions yields different loudness, which is of importance with respect to spatial sound perception as well as the evaluation of industrial noise. This work investigated the median-plane directional loudness characteristics based upon the head-related transfer functions (HRTFs) of human subjects in conjunction with the Moore's loudness model. Results show that (1) the value of loudness spectra is comparatively small at low and high frequencies, and dramatically varies with elevation in the median frequency range; (2) the loudness spectra reach minimal values in the frequency range of 5kHz ~ 10.8kHz, roughly corresponding to the pinna-related notches in HRTFs; (3) the maximal difference in loudness spectra among individuals mainly appears in elevations -30° ~ 10° and 170° ~ 210°; (4) the slight left-right asymmetry in anatomical structures leads to left-right asymmetry in loudness spectra with the mean of the maximal differences reaching about 0.43sone/ERB.

To enrich the molecular data of Pinus bungeana Zucc. ex Endl. and study the regulating factors of different morphology controled by apical dominance. In this study, de novo assembly of transcriptome annotation was performed for two varieties of Pinus bungeana Zucc. ex Endl. that are obviously different in morphology. More than 147 million reads were produced, which were assembled into 88,092 unigenes. Based on a similarity search, 11,692 unigenes showed significant similarity to proteins from Picea sitchensis (Bong.) Carr. From this collection of unigenes, a large number of molecular markers were identified, including 2829 simple sequence repeats (SSRs). A total of 158 unigenes expressed differently between two varieties, including 98 up-regulated and 60 down-regulated unigenes. Furthermore, among the differently expressed genes (DEGs), five genes which may impact the plant morphology were further validated by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The five genes related to cytokinin oxidase/dehydrogenase (CKX), two-component response regulator ARR-A family (ARR-A), plant hormone signal transduction (AHP), and MADS-box transcription factors have a close relationship with apical dominance. This new dataset will be a useful resource for future genetic and genomic studies in Pinus bungeana Zucc. ex Endl.

We developed a localized surface plasmon resonance (LSPR)-based label-free optical biosensor for detection of salbutamol (Sal). Hollow gold nanoparticles (HGNs) which deposited on transparent indium tin oxide (ITO) film coated glass was used to sensing platform. Antibody against Sal was immobilized on HGN surface to recognize the target Sal molecules. Thus, the change of LSPR peak was proportional to the concentration of Sal in the solution. The experimental results demonstrated that the LSPR immunosensor possessed a good sensitivity and a high selectivity for Sal. The detection range for Sal was from 0.05 to 0.8 μg/mL with a correlation coefficient of 0.996. The biosensor was applied for the detection for Sal in spiked animal feed and pork liver samples, and the recoveries were in the range of 97-105 %. Therefore, it is expected that this approach may offer a new method in designing label-free LSPR immunosensor for detection of small molecules.

Gold–silver core–shell triangular nanoprisms (Au/AgTNPs) were grown onto transparent indium tin oxide (ITO) thin film-coated glass substrate through a seed-mediated growth method without using peculiar binder molecules. The resulting Au/AgTNPs were characterized by scanning electron microscopy, atomic force microscopy, X-ray diffraction, UV–vis spectroscopy, and cyclic voltammograms. The peak of dipolar plasmonic resonance was located at near infrared region of ∼700 nm, which showed the refractive index (RI) sensitivity of 248 nm/RIU. Moreover, thin gold shells were electrodeposited onto the surface of Au/AgTNPs in order to stabilize nanoparticles. Compared with the Au/AgTNPs, this peak of localized surface plasmon resonance (LSPR) was a little red-shift and decreased slightly in intensity. The refractive index sensitivity was estimated to be 287 nm/RIU, which showed high sensitivity as a LSPR sensing platform. Those triangular nanoprisms deposited on the ITO substrate could be further functionalized to fabricate LSPR biosensors. Results of this research show a possibility of improving LSPR sensor by using core–shell nanostructures.

A significant phenomenon is observed when indium tin oxide (ITO) glass is used as the anode in electrochemical studies. Notable luminescent signals are observed when a pulse potential is applied to an ITO electrode in alkaline solution in the absence of a luminescent reagent. This paper discusses the mechanism of this luminescence effect in detail. The investigation reveals that the reactive oxygen species (ROSs) generated during the electrolysis are O 2 − , OH and H 2 O 2. It was also found that the singlet oxygen ( 1 O 2 ) produced subsequently acted as the indispensable light-emitting entity and the ITO was a critical intensification determinant.

In this work, the intensification of luminol electrochemiluminescence (ECL) by metallic oxide nanoparticles (MONPs), as ZnO, MnO2, In2O3 and TiO2, under alkaline condition is reported and the related mechanism is studied. It is found that all four types of those MONPs exhibit the effect toward the ECL intensification of luminol. Furthermore, the silica sol-gel film is taken to immobilize the MONPs onto the platinum electrodes. The so-obtained modified electrodes also show the enhanced ECL and better signal/noise ratio, as well improved signal stability. Finally, the ECL reagent, luminol, is immobilized together with the MONPs onto the electrode surface to perform as the ECL sensor. On resulting sensors, good linear responses are obtained toward hydrogen peroxide. The mechanism of intensification of luminol ECL by MONPs is discussed in this paper. It is proposed that the ECL intensification can be attributed to the production of reactive oxygen species, as well as the adsorption of luminol on surface of MONPs.