Fetal weight estimation based on deep neural network: a retrospective observational study.

BACKGROUND: Improving the accuracy of estimated fetal weight (EFW) calculation can contribute to decision-making for obstetricians and decrease perinatal complications. This study aimed to develop a deep neural network (DNN) model for EFW based on obstetric electronic health records. METHODS: This study retrospectively analyzed the electronic health records of pregnant women with live births delivery at the obstetrics department of International Peace Maternity & Child Health Hospital between January 2016 and December 2018. The DNN model was evaluated using Hadlock's formula and multiple linear regression. RESULTS: A total of 34824 live births (23922 primiparas) from 49896 pregnant women were analyzed. The root-mean-square error of DNN model was 189.64 g (95% CI 187.95 g-191.16 g), and the mean absolute percentage error was 5.79% (95%CI: 5.70%-5.81%), significantly lower compared to Hadlock's formula (240.36 g and 6.46%, respectively). By combining with previously unreported factors, such as birth weight of prior pregnancies, a concise and effective DNN model was built based on only 10 parameters. Accuracy rate of a new model increased from 76.08% to 83.87%, with root-mean-square error of only 243.80 g. CONCLUSIONS: Proposed DNN model for EFW calculation is more accurate than previous approaches in this area and be adopted for better decision making related to fetal monitoring.

Realizing Holism in Traditional Chinese Medicine (TCM) Consultations through the Voice of TCM (VOTCM): An Interactional Analytical Approach.

In recent years, doctor-patient communication in the context of traditional Chinese medicine (TCM) has attracted increasing attention. Highly influenced by ancient Chinese philosophy, TCM is unique in its exemplification of Chinese wisdom, particularly with respect to how the idea of zhengtǐguan () (lit. whole body concept), realized as "the idea of the whole" or simply "holism," is valued and realized in TCM consultations. Adopting an interactional analytical approach, our study aims to illustrate how TCM doctors and patients co-construct a medical consultation that can exemplify the idea of holism. Based on a spoken corpus of Mandarin Chinese totaling 443 minutes in length, this paper identifies instances of what can be labeled as the voice of TCM (VOTCM) in a typical TCM consultation that reflect the idea of holism and describes and analyzes the communicative routines that are specific to these TCM consultations. It is observed that the steps and strategies involved in the consultation not only illustrate the collaborative co-construction of holism but also point to the holistic aspect of TCM philosophy, particularly topics related to the different body parts and the lifeworld. The diagnostic explanations provided by doctors and the co-topical talks between doctors and patients at various stages of the consultation also play an important role in the co-construction and realization of holism.

Construction of a HPLC-SERS hyphenated system for continuous separation and detection based on paper substrates.

The achievement of high-throughput separation and high-sensitivity detection of complex samples has been one of the most challenging issues in the field of analytical science. The application of a single technology alone could not satisfy the above requirements. The combination of technologies with the capability of high-efficiency separation and high-sensitivity structural-recognition is highly desired to meet the technical requirements. Herein, an automatic high-performance liquid chromatography (HPLC)-surface enhanced Raman spectroscopy (SERS) hyphenated system using paper substrates as the "interface" was constructed to achieve efficient separation and real-time detection. A homogeneous Au nanoparticle was printed on the hydrophobic filter paper with the inkjet technology. The prepared substrates served as a linkage for the continuous realization of HPLC and SERS functions. The complex system was separated by HPLC, and the effluents were loaded onto automatically and continuously replaceable paper substrates for real time SERS measurements. The continuous rapid separation and real-time detection of various two-component mixtures were achieved with the separation efficiency and detection sensitivity of each technology. The results demonstrated that the HPLC-SERS hyphenated system exhibited the complementary capability of the on-line separation and continuous structural identification of illegal additives in real samples. The detection sensitivity was increased by an order of magnitude to reach 10-5 mol dm-3, and the efficiency and accuracy for the separation and identification on the multi-components samples were higher than those of the individual HPLC or SERS technology. It is believed that the continuous paper substrate-based HPLC-SERS hyphenated system would be developed as a promising technique for the separation and identification of multi-components mixtures with high throughput.

Antepartum sleep quality, mental status, and postpartum depressive symptoms: a mediation analysis.

BACKGROUND: Poor sleep quality and maternal mood disturbances are common during pregnancy and may play pivotal roles in the development of postpartum depression. We aim to examine the trajectories of sleep quality and mental health in women from early pregnancy to delivery and explore the mediating effects of sleep quality and mental status on the link between antepartum depressive symptoms and postpartum depressive symptoms. METHODS: In an ongoing prospective birth cohort, 1301 women completed questionnaires in the first, second and third trimesters and at 6 weeks postpartum. In each trimester, sleep quality was measured utilizing the Pittsburgh Sleep Quality Index (PSQI), and mental health was assessed with the Center for Epidemiologic Studies Depression Scale (CES-D), the Self-Rating Anxiety Scale (SAS) and the Perceived Stress Scale (PSS). Postpartum depressive symptoms were evaluated by the Edinburgh Postnatal Depression Scale (EPDS). The bootstrap method was used to test the mediation effect. RESULTS: The PSQI, CES-D, and SAS scores presented U-shaped curves across the antenatal period while the PSS score followed a descending trend. Antenatal sleep quality, depressive symptoms, anxiety symptoms and perceived stress all predicted depressive symptoms at 6 weeks postpartum. The influence of antepartum depressive symptoms on postpartum depressive symptoms was mediated by antepartum sleep quality and anxiety symptoms, which accounted for 32.14%, 39.25% and 31.25% in the first, second and third trimesters (P = 0.002, P = 0.001, P = 0.001, respectively). CONCLUSIONS: Poor sleep quality and anxiety symptoms in pregnancy mediated the relationship between antepartum depressive symptoms and postpartum depressive symptoms. Interventions aimed at detecting and managing sleep quality and elevated anxiety among depressed women in pregnancy warrant further investigation as preventative strategies for postpartum depression.

Effect of an individualised nutritional intervention on gestational diabetes mellitus prevention in a high-risk population screened by a prediction model: study protocol for a multicentre randomised controlled trial.

BACKGROUND: The ability of a preventive nutritional intervention to reduce the morbidity of gestational diabetes mellitus (GDM) remains controversial. We aim to assess whether GDM can be prevented by an individualised nutritional intervention in pregnant women who are at high risk for the disease based on a prediction model. METHODS/DESIGN: A multicentre randomised controlled trial was designed to assess the efficacy of an individualised nutritional intervention for the prevention of GDM in a high-risk population screened by a novel prediction model in the first trimester. Pregnant women evaluated to be at high risk for GDM by the prediction model at less than 14 gestational weeks will be included. Women with pre-existing chronic diseases, including pregestational diabetes, or who are currently prescribed medicines that affect glucose values will be excluded. Allocation to intervention/control at a ratio of 1:1 will be conducted by a computerized randomisation system. The intervention group will complete 3-day food records and receive 3 individualised nutritional consultations with professional dieticians before the oral glucose tolerance test. The primary intention of the intervention is to promote a long-term healthy dietary pattern and prevent excessive gestational weight gain throughout pregnancy. The control group will complete 3-day food records at designated gestational weeks and receive standard antenatal care according to local health care provisions. The primary outcome is the incidence of GDM according to the criteria of the International Association of Diabetes and Pregnancy Study Group (IADPSG). A sample of 464 participants will provide 80% power to detect a 30% reduction in GDM incidence (α = 0.05 two tailed, 10% dropout). A total of 500 participants will be recruited. DISCUSSION: To date, this is the first randomised controlled trial aimed to evaluate the protective effect of an individualised nutritional intervention against GDM based on a logistic regression prediction model. Eligibility is not limited to obese women or singleton pregnancies, as in previous studies. This pragmatic trial is expected to provide valuable information on early screening and effective GDM prevention methods. TRIAL REGISTRATION NUMBER: ChiCTR, ChiCTR1900026963 . Registered 27 October 2019.

Associations between Maternal Sleep Quality Throughout Pregnancy and Newborn Birth Weight.

Objective: Poor sleep quality is common during pregnancy. Although a few studies have investigated the associations between maternal sleep quality and fetal birth weight (BW), no evidence has been clearly demonstrated. Our aim was to investigate the effects of sleep quality during pregnancy on the newborn BW z-scores. Participants: 1466 mother-infant pairs were included in the present study based on an ongoing prospective cohort. Methods: Questionnaires including the Pittsburgh Sleep Quality Index (PSQI) and scales for psychosocial status were administered at each trimester. BW z-scores were calculated based on the INTERGROWTH-21st standard. A generalized estimating equation model was applied to evaluate the associations between trimester-specific sleep quality and newborn BW after adjusting for potential confounders. Multivariable logistic regression models were applied to examine the impacts of maternal sleep quality on small-for-gestational-age (SGA) or low birth weight (LBW). Results: We found that maternal PSQI scores in the first and third trimesters were negatively associated with BW z-scores among female newborns (ß = -0.032, 95% CI: -0.063, -0.001, P= .043; ß = -0.031, 95% CI: -0.060, -0.003, P= .033, respectively). However, no relationship was observed between maternal sleep quality and BW in male neonates. Additionally, poor sleep quality in late pregnancy was a risk factor for LBW (OR = 1.501, 95% CI: 1.082-2.082). Conclusions: The BW z-scores of female newborns decreased as maternal sleep quality in the first and third trimesters worsened. This finding suggests that sleep during pregnancy may influence fetal weight in a trimester- and gender-specific manner.

Interference Cancellation Based Spectrum Sharing for Massive MIMO Communication Systems.

Cellular network operators are predicting an increase in space of more than 200 percent to carry the move and tremendous increase of total users in data traffic. The growing of investments in infrastructure such as a large number of small cells, particularly the technologies such as LTE-Advanced and 6G Technology, can assist in mitigating this challenge moderately. In this paper, we suggest a projection study in spectrum sharing of radar multi-input and multi-output, and mobile LTE multi-input multi-output communication systems near m base stations (BS). The radar multi-input multi-output and mobile LTE communication systems split different interference channels. The new approach based on radar projection signal detection has been proposed for free interference disturbance channel with radar multi-input multi-output and mobile LTE multi-input multi-output by using a new proposed interference cancellation algorithm. We chose the channel of interference with the best free channel, and the detected signal of radar was projected to null space. The goal is to remove all interferences from the radar multi-input multi-output and to cancel any disturbance sources from a chosen mobile Communication Base Station. The experimental results showed that the new approach performs very well and can optimize Spectrum Access.

Ability of Lactobacillus plantarum lipoteichoic acid to inhibit Vibrio anguillarum-induced inflammation and apoptosis in silvery pomfret (Pampus argenteus) intestinal epithelial cells.

Lipoteichoic acid (LTA) is a major constituent of the cell wall of Gram-positive bacteria. The structure and immunomodulation of LTA vary greatly between different species. LTA from Lactobacillus plantarum has been shown to exert anti-pathogenic effects. Vibrio anguillarum is a major causative agent of vibriosis, one of the most prevalent fish diseases. The purpose of this study was to examine the effects of L. plantarum LTA on V. anguillarum growth, adhesion, and induced inflammation and apoptosis in intestinal epithelial cells of silvery pomfret (Pampus argenteus). Our results showed that L. plantarum LTA was unable to inhibit V. anguillarum growth; however, it significantly inhibited adhesion of V. anguillarum. It also showed significant inhibitory effects on EHEC-induced inflammation and apoptosis by modulating the expression of NF-κB (nuclear factor kappa B), IκB (inhibitor of NF-κB), Bcl2 (B-cell leukemia/lymphoma-2), BAX (Bcl-2-associated X protein), IL-8 (interleukin 8) and TNF-α (tumor necrosis factor-α), and via inhibition of caspase-9 and caspase-3 activation. These data extend our understanding of the beneficial effects of L. plantarum LTA, which is related to the inhibition of V. anguillarum, and suggest that L. plantarum LTA has potential as a new therapeutic agent against V. anguillarum-caused vibriosis in fish.

Molecular characterization and expression analysis of toll-like receptor 2 in response to bacteria in silvery pomfret intestinal epithelial cells.

Toll-like receptor 2 (TLR2) has been shown to play a crucial role in the host defense of pathogenic microbes in innate immunity. In this study, the full-length cDNA of TLR2 in silvery pomfret (Pampus argenteus) was cloned by homology cloning and the rapid amplification of cDNA ends (RACE) technique. The complete cDNA sequence of TLR2 was 2932 bp, containing an open reading frame (ORF) of 2469 bp encoding 822 amino acids. A multiple alignment analysis of the silvery pomfret TLR2 protein-coding sequence with other known TLR2 sequences from Oplegnathus fasciatus, Epinephelus coioides, Larimichthys crocea, Miichthys miiuy, Oreochromis niloticus, Paralichthys olivaceus, Trematomus bernacchii, Sparus aurata, and Chionodraco hamatus exhibited a high degree of homology of 78.83%, 75.91%, 74.21%, 74.94%, 71.95%, 72.57%, 73.68%, 75%, and 72.52 respectively, between these fish. Analysis of the TLR2 domain structures indicated that TLR2 from the silvery pomfret has the typical structural features of proteins that belong to the TLR family, including one transmembrane domain, eleven leucine-rich repeats (LRRs), and one Toll/IL-1 receptor homology domain (TIR). In vitro immunostimulation experiments revealed that Lactobacillus plantarum and Clostridium butyricum induce high levels of TLR2 mRNA and protein expression, but they induce only moderate levels of IL-8 and TNF-α production compared to Vibrio anguillarum. This suggests that TLR2 might play a vital role in the L. plantarum and C. butyricum-mediated immune response. In contrast, V. anguillarum significantly increased the secretion of IL-8 and TNF-α and induced cell apoptosis and necrosis. Due to the lower expression of TLR2 and higher levels of IL-8 and TNF-α induced by V. anguillarum, we hypothesize that a V. anguillarum infection is independent of the TLR2-induced production of pro-inflammatory cytokines. These results indicate that TLR2 may be involved in molecular interactions between the host and commensal bacteria, that exist in the silvery pomfret intestinal tract.

Underwater smart glasses: A visual-tactile fusion hazard detection system.

Marine activities typically face various risk factors such as marine animal attacks or unexpected collisions. In this paper, we develop underwater smart glasses (USGs) based on visual-tactile fusion for underwater hazard detection in real-time, ensuring operational safety. The proposed USG is composed of the vision module by artificial intelligence (AI)-enabled optical sensing and the tactile module by triboelectric metamaterials-enabled mechanical sensing. The vision module is obtained based on the underwater target detection algorithm you only look once-underwater hazard (YOLO-UH) developed by the dataset to detect toxic marine organisms in the visual field. The tactile module is designed with the kirigami tribo-materials (KTMs) to sensitively detect and warn of collisions outside the visual field. Through numerical simulations, laboratory tests, and real-world experiments, we validated the performance of both modules. The reported USG with its visual-tactile fusion concept enables near-far all-around hazard detection and reduces the danger for divers working underwater.

Improving insight into the localized electrochemical Volmer reaction based on surface enhanced Raman spectroscopy and collisions.

An operando EC-SERS strategy was successfully developed for monitoring the Volmer reaction based on dynamic collisions. Its feasibility and universality were verified, and it provided a promising approach for visualizing a localized surface reaction.

Insight into Impacts of π-π Assembly on Phthalocyanine Based Heterogeneous Molecular Electrocatalysis.

Electrochemical CO2 reduction (CO2R) to feedstocks competes with the hydrogen evolution reaction (HER). Cobalt phthalocyanine (CoPc) immobilized onto carbon driven by π-π interaction represents a classical type of heterogeneous molecular catalyst for CO2R. However, the impacts of π conjugation on the electrocatalysis have not been clarified. Herein, the electrochemical properties of CoPc were investigated by comparison of its analogue to 2,3-naphthalocyanine cobalt (NapCo) having extended π conjugation. It is found that CoPc is redox-active on carbon to provide low oxidized Co sites for improving the CO2R activity and selectivity, while NapCo on carbon turned out to be redox-inert leading to lower performance. In addition, the redox-mediated mechanism for CO2R on CoPc tends to operate with increasing electrolyte alkalinity, which further enhances the reaction selectivity. We speculated that moderate π conjugation allows the redox-mediated mechanism on CoPc, which is critical to promote CO2R performance while depressing the competing HER.

Association of serum folic acid levels in response to fasting blood glucose in early pregnancy with the risk of gestational diabetes mellitus: A retrospective cohort study.

OBJECTIVE: With increasingly prevalent folic acid consumption in early pregnancy, concerns about its potentially negative effect on maternal metabolism have been raised. Recent findings regarding folic acid levels in the first trimester and the risk of gestational diabetes mellitus have been inconclusive. The aim of this study was to investigate the association of folic acid status in early pregnancy with gestational diabetes mellitus as well as examine whether glucose levels can be modulated by folic acid status during the same first trimester. METHODS: This was a retrospective cohort study based on 27 128 Chinese pregnant women who registered during their first prenatal visit from January 2015 to December 2019. Serum folic acid and fasting blood glucose concentrations were measured during the 9th to 13th gestational weeks. Binary logistic regression was applied to estimate the odds ratios of gestational diabetes mellitus by using the serum folic acid levels quartiles with adjustment for major confounders. To investigate the potential effect of modifying key risk factors for gestational diabetes mellitus, we established subgroups, in which analyses were stratified by age (<25, 25-29, 30-34, and ≥35 y), parity (nulliparous and parous), prepregnancy body mass index (< 18.5, 18.5-23.9, and ≥ 24 kg/m2), and family history of diabetes (yes and no). RESULTS: The positive association between maternal folate concentrations and fasting blood glucose was observed: the risk for hyperglycemia was higher in those in the middle (Q3) and higher (Q4) quartiles compared with those in Q1 and Q2. A higher risk for gestational diabetes mellitus was found in hyperglycemia of early pregnant women with high folate concentrations (Q3: odds ratio = 5.63; 95% CI, 4.56-6.95, and Q4: odds ratio = 5.57; 95% CI, 4.68-6.64) compared with normal fasting glucose mothers with folate concentrations in Q1 and Q2 after accounting for multiple covariables. Similar patterns were observed for different subgroups. Restricted cubic spline plots had a positive correlation of serum folic acid level with fasting blood glucose concentration as well as risk of gestational diabetes mellitus in a nonlinear pattern, with 32.5 nmol/L as the cutoff point for folic acid level. CONCLUSIONS: Our findings underscore the importance of maintaining an appropriate folic acid concentration for preserving a lower risk of gestational diabetes mellitus, especially in women with relatively higher blood glucose in early pregnancy. Additionally, folic acid concentration > 32.5 nmol/L may be considered a risk factor for gestational diabetes mellitus. This research suggested that folic acid levels should be monitored during the first trimester from the first prenatal checkup to prevent adverse effects of excessive folic acid intake.

Rh-Catalyzed C-H Alkynylation of Indole Derivatives with Silver(I)-Controlled Regiodivergence.

We have disclosed silver(I)-induced switching of regioselectivity in rhodium-catalyzed C-H alkynylation of indole derivatives with the help of a pivaloyl directing group by tuning C-H metalation modes. The judicious choice of AgOAc, Ag2O, and Ag2CO3 affords an array of C2-alkynylated indoles, C4-alkynylated indoles, and C2,C4-dialkynylated indoles, respectively. The synthetic utility of the alkyne fragment is demonstrated by derivatization into valuable indole-based compounds.

YOLOX-DG robotic detection systems for large-scale underwater concrete structures.

Large-scale complex underwater concrete structures have structural damage and the traditional damage detection method mostly uses manual identification, which is inaccurate and inefficient. Therefore, robotic detection systems have been proposed to replace manual identification for underwater concrete structures in ocean engineering. However, the highly corrosive and disruptive environment of the ocean poses great difficulties for the application. Here, we develop a manta ray-inspired underwater robot with well controllability to establish the damage datasets of underwater concrete structures, proposing the YOLOX-DG algorithm to improve the damage detection accuracy, and integrating the model into the robotic detection systems for underwater concrete damages. Eventually, the system is used for ocean testing in real applications (i.e., underwater marine harbors around the East China Sea), and satisfactory detection performance is obtained. The reported manta ray-inspired robotic detection system can be used to accurately monitor and analyze the underwater regions.

Identification of Floral Volatile Components and Expression Analysis of Controlling Gene in Paeonia ostii 'Fengdan' under Different Cultivation Conditions.

In order to explore the release rule of floral volatile substances and the diurnal variation of different flower development stages of Paeonia ostii 'Fengdan' in potted and ground-planted conditions, dynamic headspace adsorption combined with gas chromatography-mass spectrometry(GC-MS) was used to analyze the dynamic changes in floral volatile components and contents. Quantitative real-time PCR (qRT-PCR) was used to analyze changes in flower fragrance-regulating genes PsPAL, PsTPSs, and PsbHLH at different flower development stages and a daily change process at the full-blooming stage. The results show that there were differences in aroma components and contents of Paeonia ostii 'Fengdan' at different flower development stages and different time quantum of every day. There were 25 and 28 aroma components identified in 7 flower development stages of tree peonies planted in pots and in the field, respectively, and 23 and 22 aroma components identified at different time quantum of the day, of which the largest and highest content was alkanes. The main characteristic aroma substances were (E)-ß-ocimene, 1,3,5-trimethoxybenzene, 2,4-di-tert-butylphenol, methyl jasmonate, nerol, and cinnamyl alcohol; released amounts of the abovementioned substances varied depending on the development stage and the time of the day. The expression of flower fragrance-controlling genes (PsPAL, PsTPSs, and PsbHLH) in tree peonies varied greatly in different conditions. The results of this study provide a valuable resource to investigate floral fragrance formation in tree peonies.

Real-time tracking of colloidal stability based on collision behaviors probed by surface-enhanced Raman spectroscopy.

HYPOTHESIS: The dynamic behaviors of colloidal particles have already been considered as one of the key issues in their practical application, such as aggregation and dispersion. However, it is still remained significant challenge in developing the real time techniques to capture their dynamic tracks. The nano/subnanometer scale gap generated during the colloidal collisions served as the critical location for amplifying the Raman signal, so called as gap ("hot spots") based surface enhanced Raman spectroscopy (SERS). The alternating reversible "spike" of SERS intensity and irreversible step in baseline intensity are contributed to the preferred stability and the aggregation of colloid respectively. EXPERIMENTS: A facile approach is developed to track colloidal stability in real-time based on collisions and SERS. The effects of particle concentration, the dispersion medium, and solution pH on colloidal stability are systematically investigated, and the SERS intensity of a simulated single-like "hot spot" was calculated by combining a SEM position with SERS mapping technology to estimate the intensity of single-particle collision. FINDINGS: The colloidal particles exhibited higher stability in the solution with lower particle concentration, higher viscosity and neutral medium. The SERS intensity of single-particle collision was estimated to be about 2.06 × 10-7 counts, and the average number of collisions for the 0.13 mmol/dm3 SiO2@Ag solution was about 1.11 × 108 times/spike in the "spikes" with SERS intensity of 23.0 cps. It is believed that the SERS based strategy would be developed as a promising tool for obtaining the deeper insight into the nature of collisions in the colloidal science.

MoS2/Au Heterojunction Catalyst for SERS Monitoring of a Fenton-like Reaction.

Fenton technology is one of advanced oxidation process (AOP) methods to treat wastewater through chemical oxidation. Due to the limitations of classical iron-based catalysts, it is still challenging to find suitable catalysts for Fenton-like reactions. Here, MoS2/Au heterojunctions were successfully synthesized by reduction of chloroauric acid in the solution of layered MoS2 prepared by hydrothermal method. As a model molecule, methylene blue (MB) was used as the species to be degraded to evaluate the performance of the catalyst. It was determined by UV-visible spectra that the optimal catalyst can be obtained when MoS2 (mg): HAuCl4 (wt. % mL) is 2:2. The Fenton-like reaction process was monitored by introducing highly sensitive surface enhanced Raman spectroscopy (SERS). The results show that MB can be degraded by 83% in the first 10 min of the reaction, indicating that MoS2/Au has good catalytic performance. In addition, as a fingerprint spectrum, SERS was used to preliminarily analyze the molecular structure changes during the degradation process. The result showed that C-N-C bond was easier to break than the C-S-C bond. NH2 group and the fused ring were destroyed at the comparable speed at the first 30 min. In terms of application applicability, it was showed that MB degradation had exceeded 95% at all the three pH values of 1.4, 5.0, and 11.1 after the reaction was carried out for 20 min. The test and analysis of the light environment showed that the catalytic efficiency was significantly improved in the natural light of the laboratory compared to dark conditions. The possible mechanism based on ·OH and ·O2- from ESR data was proposed. In addition, it was demonstrated to be a first-order reaction from the perspective of kinetics. This study made a positive contribution to broaden of the applicable conditions and scope of Fenton-like reaction catalysts. It is expected to be used as a non-iron catalyst in practical industrial applications. From the perspective of detection method, we expect to develop SERS as a powerful tool for the in situ monitoring of Fenton-like reactions, and to further deepen our understanding of the mechanism.

Resolving nanostructure and chemistry of solid-electrolyte interphase on lithium anodes by depth-sensitive plasmon-enhanced Raman spectroscopy.

The solid-electrolyte interphase (SEI) plays crucial roles for the reversible operation of lithium metal batteries. However, fundamental understanding of the mechanisms of SEI formation and evolution is still limited. Herein, we develop a depth-sensitive plasmon-enhanced Raman spectroscopy (DS-PERS) method to enable in-situ and nondestructive characterization of the nanostructure and chemistry of SEI, based on synergistic enhancements of localized surface plasmons from nanostructured Cu, shell-isolated Au nanoparticles and Li deposits at different depths. We monitor the sequential formation of SEI in both ether-based and carbonate-based dual-salt electrolytes on a Cu current collector and then on freshly deposited Li, with dramatic chemical reconstruction. The molecular-level insights from the DS-PERS study unravel the profound influences of Li in modifying SEI formation and in turn the roles of SEI in regulating the Li-ion desolvation and the subsequent Li deposition at SEI-coupled interfaces. Last, we develop a cycling protocol that promotes a favorable direct SEI formation route, which significantly enhances the performance of anode-free Li metal batteries.