Biexcitons-plasmon coupling of Ag@Au hollow nanocube/MoS2 heterostructures based on scattering spectra.

The strong interaction between light and matter is one of the current research hotspots in the field of nanophotonics, and provides a suitable platform for fundamental physics research such as on nanolasers, high-precision sensing in biology, quantum communication and quantum computing. In this study, double Rabi splitting was achieved in a composite structure monolayer MoS2 and a single Ag@Au hollow nanocube (HNC) in room temperature mainly due to the two excitons in monolayer MoS2. Moreover, the tuning of the plasmon resonance peak was realized in the scattering spectrum by adjusting the thickness of the shell to ensure it matches the energy of the two excitons. Two distinct anticrossings are observed at both excitons resonances, and large double Rabi splittings (90 meV and 120 meV) are obtained successfully. The finite-difference time domain (FDTD) method was also used to simulate the scattering spectra of the nanostructures, and the simulation results were in good agreement with the experimental results. Additionally, the local electromagnetic field ability of the Ag@Au hollow HNC was proved to be stronger by calculating and comparing the mode volume of different nanoparticles. Our findings provides a good platform for the realization of strong multi-mode coupling and open up a new way to construct nanoscale photonic devices.

Semiparametric regression analysis of length-biased and partly interval-censored data with application to an AIDS cohort study.

Length-biased data occur often in many scientific fields, including clinical trials, epidemiology surveys and genome-wide association studies, and many methods have been proposed for their analysis under various situations. In this article, we consider the situation where one faces length-biased and partly interval-censored failure time data under the proportional hazards model, for which it does not seem to exist an established method. For the estimation, we propose an efficient nonparametric maximum likelihood method by incorporating the distribution information of the observed truncation times. For the implementation of the method, a flexible and stable EM algorithm via two-stage data augmentation is developed. By employing the empirical process theory, we establish the asymptotic properties of the resulting estimators. A simulation study conducted to assess the finite-sample performance of the proposed method suggests that it works well and is more efficient than the conditional likelihood approach. An application to an AIDS cohort study is also provided.

Charge transfer effect: a new assignment of the abnormal optical absorption band of gold nanoparticles.

As a significant accompanying phenomenon of surface-enhanced Raman scattering (SERS), the addition of foreign molecules to colloidal gold or silver nanoparticles results in a new abnormal optical absorption (AOA) band, which usually appears in the long-wavelength region. The assignment of this AOA band has long been debated as an important issue that is desired to be addressed in the SERS field, which is crucial for a clear understanding of the SERS enhancement mechanism and beneficial to surface plasmonics. In this study, both the calculated and measured optical absorptions of gold nanoparticle monomers and dimers as well as their interactions with adsorbed molecules, showed that the AOA band in the long-wavelength region which was assigned to the characteristic longitudinal localized surface plasmon resonance (LSPR) effect of gold nanoparticle chain aggregates in conventional SERS electromagnetic theory, should be attributed to the charge-transfer resonance absorption from gold nanoparticles to adsorbed molecules. This was further confirmed by the corresponding SERS effects. As the excitation wavelength at 785 nm was resonant with the broad AOA band centered at 750 nm, the SERS peaks of the adsorbed pyridine molecules could be dramatically enhanced due to the charge-transfer resonance effect. In contrast, under an excitation wavelength of 532 nm, the SERS peaks appeared very weak, although the excitation wavelength was resonant with the LSPR absorption band of the individual gold nanoparticles.

A semi-parametric weighted likelihood approach for regression analysis of bivariate interval-censored outcomes from case-cohort studies.

The case-cohort design was developed to reduce costs when disease incidence is low and covariates are difficult to obtain. However, most of the existing methods are for right-censored data and there exists only limited research on interval-censored data, especially on regression analysis of bivariate interval-censored data. Interval-censored failure time data frequently occur in many areas and a large literature on their analyses has been established. In this paper, we discuss the situation of bivariate interval-censored data arising from case-cohort studies. For the problem, a class of semiparametric transformation frailty models is presented and for inference, a sieve weighted likelihood approach is developed. The large sample properties, including the consistency of the proposed estimators and the asymptotic normality of the regression parameter estimators, are established. Moreover, a simulation is conducted to assess the finite sample performance of the proposed method and suggests that it performs well in practice.

PITX2 regulates steroidogenesis in granulosa cells of dairy goat by the WNT/ß-catenin pathway.

Paired-like homeodomain transcription factor 2 (PITX2), a major driver of multiple tissue development, is a transcription factor that regulates gene expression in organisms. However, it is unknown if PITX2 regulates goat granulosa cell (GC) steroidogenesis. Therefore, we investigated the role and mechanism of PITX2 in GC steroidogenesis. In our study, PITX2 significantly facilitated the secretion level of estrogen and progesterone through increasing CYP11A1, CYP19A1, and STAR mRNA and protein expressions in GCs. Furthermore, PITX2 participated in the WNT pathway, enhancing the production of E2 and P4 in GCs. PITX2 in GCs increased the DVL-1 and CTNNB1 expression, involved in the WNT/ß-catenin signaling pathway related to steroidogenesis. Moreover, GC steroidogenesis-related gene translation was decreased by CTNNB1-siRNA but enhanced when transfected with PITX2. PITX2 regulates secretion of E2 and P4 from GCs via the WNT/ß-catenin pathway and alters GC proliferation and steroidogenesis. These findings will help understand the role of PITX2 in goat ovarian follicular development and oocyte maturation.

Surgical outcomes of two different reconstruction routes for esophagectomy in esophageal cancer patients: a meta-analysis.

To evaluate the effects of two different reconstruction routes (the posterior mediastinal route (PR) and the retrosternal route (RR)) on the surgical outcomes of patients after esophagectomy for esophageal carcinoma. PubMed, Embase, Web of Science and Scopus were searched from database inception to March 2021. Randomized controlled trials (RCTs) and case-control trials on the surgical outcomes of patients undergoing esophagectomy via one of the two routes were included. RevMan 5.3 software was used for the meta-analysis. In total, 19 studies were included, 8 were RCTs and 11 were case-control studies. The meta-analysis showed that among the case-control trials, the PR had reduced rates of anastomotic leakage [odds ratio (OR) = 0.56, 95% confidence interval (CI) (0.43, 0.74), P < 0.01]. In addition, it had reduced rates of anastomotic stenosis [OR = 0.42, 95% CI (0.30, 0.59), P < 0.01] and pulmonary complications [OR = 0.63, 95% CI (0.47, 0.84), P < 0.01]. However, there was no significant difference in cardiac complications [RCTs, relative risk (RR) = 0.57, 95% CI (0.29, 1.11), P = 0.10; case-control trials, OR = 1.06, 95% CI (0.70, 1.62), P = 0.78] or postoperative mortality [RCTs, RR = 0.47, 95% CI (0.19, 1.16), P = 0.10; case-control trials, OR = 0.68, 95% CI (0.32, 1.44), P = 0.31]. Compared with the RR, the PR had reduced rates of anastomotic leakage, anastomotic stenosis and pulmonary complications.

Comparison of single-port vs. two-port VATS technique for primary spontaneous pneumothorax.

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) has been used for thoracic surgery for about two decades. As the trend in VATS is to use fewer ports to decrease postoperative complications, we compared the results of our experience with single-port and two-port VATS for primary spontaneous pneumothorax (PSP). MATERIAL AND METHODS: This is a non-randomized retrospective study. From January 2017 to December 2018, 104 patients with PSP underwent VATS. Fifty-six patients received single-port VATS and 48 patients received two-port VATS. Operation time, blood loss, number of staplers used, drainage time, postoperative hospital stay, complications, chest wall paresthesia, visual analog scale (VAS) pain scores, and patient satisfaction scale scores were compared between the two groups. RESULTS: There was no difference in age, gender, body mass index (BMI), smoking status, surgical indication, and involved side between the two groups. The procedures performed in the single-port group were similar to those performed in the two-port group. No significant difference was found in operation time, blood loss, number of staplers used, drainage time, and recurrence rate. The rate of chest wall paresthesia was lower in the single-port group than in the two-port group (28.6 vs. 52.1%, p = .014). The VAS scores in the single-port group were lower than those in the two-port group at 24 and 48 h (p = .032 and p = .004). CONCLUSIONS: Compared with two-port VATS, single-port VATS for PSP showed more favorable results in terms of postoperative paresthesia and pain. The single-port procedure may be considered a good alternative to the standard thoracoscopic treatment of PSP. Abbreviations: VATS: Video-assisted thoracic surgery; PSP: primary spontaneous pneumothorax.

A pairwise pseudo-likelihood approach for left-truncated and interval-censored data under the Cox model.

Left truncation commonly occurs in many areas, and many methods have been proposed in the literature for the analysis of various types of left-truncated failure time data. For the situation, a common approach is to conduct the analysis conditional on truncation times, and the method is relatively simple but may not be efficient. In this paper, we discuss regression analysis of such data arising from the proportional hazards model that also suffer interval censoring. For the problem, a pairwise pseudo-likelihood approach is proposed that aims to recover some missing information in the conditional methods. The resulting estimator is shown to be consistent and asymptotically normal. A simulation study is conducted to assess the performance of the proposed method and suggests that it works well in practical situations and is indeed more efficient than the existing method. The approach is also applied to a set of real data arising from an AIDS cohort study.

The smart growth of self-assembled silver nanoloops.

Enclosed silver nanoloops have unique features in manipulating and controlling light. However, even the conception of their growth mechanism has not been established. The intermediate structure at the growth stage were revealed as the crucial issue for studying their smart growth mechanism of silver nanoloops and nanowires. Early growth stage showed that silver nanorods and nanoparticles were grown in their respective polyvinylpyrrolidone micelles. Then, the silver nanorods and nanoparticles were assembled in a rod-particle-rod pattern via micelle-micelle coupling, forming linear silver nanowires. These silver nanowires were attracted by Van der Waals forces forming the initial nanoloop. Notably, there was a silver nanoparticle between the ends of two adjacent nanowires. This silver nanoparticle acted like solder and played a crucial role in connecting the two adjacent nanowires; consequently, a silver nanoloop was formed. This finding also suggested that similar smart growth patterns might exist for other one-dimensional and looped nanomaterials.

MicroRNA-145 performs as a tumor suppressor in human esophageal squamous cell carcinoma by targeting phospholipase C epsilon 1.

Esophageal squamous cell carcinoma (ESCC) is the leading pathologic type in China. miR-145 has been reported to be downregulated in multiple tumors. This study was aimed to investigate the role of miR-145 in ESCC. miR-145 expression was investigated in 65 ESCC samples as well as four ESCC cell lines by quantitative real-time polymerase chain reaction (qRT-PCR). Targetscan 6.2 website (http://www.targetscan.org/) was used to predict the targets of miR-145. Expression of phospholipase C epsilon 1 (PLCE1) messenger RNA and protein was detected by qRT-PCR or Western blot. MTT and wound healing assay were conducted to explore the effects of miR-145 on the proliferation and migration of ESCC cell lines, respectively. miR-145 was significantly decreased in ESCC tissues. An inverse correlation between miR-145 and invasion depth and TNM stage were observed. PLCE1 was a direct target of miR-145, and the expression of PLCE1 was inversely correlated with miR-145 expression in ESCC tissues. In addition, overexpression of miR-145 suppressed cell proliferation and migration in ESCC cells. The enforced expression of PLCE1 partially reversed the suppressive effect of miR-145. These results prove that miR-145 may perform as a tumor suppressor in ESCC by targeting PLCE1.

Surface-Nanostructured Single Silver Nanowire: A New One-Dimensional Microscale Surface-Enhanced Raman Scattering Interface.

One-dimensional microscale surface-enhanced Raman scattering (SERS)-active interfaces have been intriguing as a newly emerging class of SERS interfaces compared to conventional macroscale SERS substrates. In this work, a stable surface-nanostructured single silver nanowire was fabricated. The nanostructures on the nanowire are formed by nanoscale silver crystal dots with diameters of 20-50 nm. The SERS signals of the crystal violet probe molecules adsorbed on the nanostructures are dramatically enhanced by both electromagnetic and chemical effects. The hot spots generated at the junctions of adjacent nanoscale dots yield highly efficient surface plasmon resonance. Simultaneously, the charge transfer on the atomic-scale silver cluster located at the nanostructured interface causes an enhancement similar to Raman resonance. The intensity distributions of the SERS peaks on the surface-nanostructured single nanowire are characterized by SERS mapping. It is found that, although the intensities of the SERS peaks are different, their SERS mapping images show uniform SERS enhancement distributions, whereas the noticeable SERS intensity distributions on the single smooth silver nanowire are mainly located on the two ends of the nanowire. A large number of nanoscale crystal dots along with the atomic-scale silver clusters are uniformly and densely distributed on the surface of the single roughened nanowire; these structural attributes induce a uniform and large surface plasmon resonance and charge transfer enhancements on the entire surface of the nanowire. This work indicates that the surface-nanostructured single silver nanowire, synthesized using a quite simple preparation method, performs as an excellent one-dimensional microscale SERS substrate with uniform and high enhancement characteristics, which shows high potential for applications as a new class of SERS-active substrates. Furthermore, the higher enhancement factor of the microscale SERS interfaces can be achieved by introducing other roughened nanowires to assemble a dimer and a trimer as micro-SERS substrates, which is consistent with the dark-field measurements.

Regression analysis of interval-censored failure time data with possibly crossing hazards.

Interval-censored failure time data occur in many areas, especially in medical follow-up studies such as clinical trials, and in consequence, many methods have been developed for the problem. However, most of the existing approaches cannot deal with the situations where the hazard functions may cross each other. To address this, we develop a sieve maximum likelihood estimation procedure with the application of the short-term and long-term hazard ratio model. In the method, the I-splines are used to approximate the underlying unknown function. An extensive simulation study was conducted for the assessment of the finite sample properties of the presented procedure and suggests that the method seems to work well for practical situations. The analysis of an motivated example is also provided.

A semiparametric regression cure model for doubly censored data.

This paper discusses regression analysis of doubly censored failure time data when there may exist a cured subgroup. By doubly censored data, we mean that the failure time of interest denotes the elapsed time between two related events and the observations on both event times can suffer censoring (Sun in The statistical analysis of interval-censored failure time data. Springer, New York, 2006). One typical example of such data is given by an acquired immune deficiency syndrome cohort study. Although many methods have been developed for their analysis (De Gruttola and Lagakos in Biometrics 45:1-12, 1989; Sun et al. in Biometrics 55:909-914, 1999; 60:637-643, 2004; Pan in Biometrics 57:1245-1250, 2001), it does not seem to exist an established method for the situation with a cured subgroup. This paper discusses this later problem and presents a sieve approximation maximum likelihood approach. In addition, the asymptotic properties of the resulting estimators are established and an extensive simulation study indicates that the method seems to work well for practical situations. An application is also provided.

Unified Treatment for Plasmon-Exciton Co-driven Reduction and Oxidation Reactions.

Revealing the nature of plasmon-exciton co-driven surface catalytic reactions is important and urgent for developing potential applications in energy and environmental science. In this work, we propose a mechanism for plasmon-exciton co-driven surface catalytic reactions based on our experimental results. We provide a method for a unified treatment for reduction and oxidation reactions, which not only strongly supports our proposed mechanism but also promotes a deeper understanding of plasmon-exciton co-driven surface catalytic reactions.

Regression analysis of case K interval-censored failure time data in the presence of informative censoring.

Interval-censored failure time data occur in many fields such as demography, economics, medical research, and reliability and many inference procedures on them have been developed (Sun, 2006; Chen, Sun, and Peace, 2012). However, most of the existing approaches assume that the mechanism that yields interval censoring is independent of the failure time of interest and it is clear that this may not be true in practice (Zhang et al., 2007; Ma, Hu, and Sun, 2015). In this article, we consider regression analysis of case K interval-censored failure time data when the censoring mechanism may be related to the failure time of interest. For the problem, an estimated sieve maximum-likelihood approach is proposed for the data arising from the proportional hazards frailty model and for estimation, a two-step procedure is presented. In the addition, the asymptotic properties of the proposed estimators of regression parameters are established and an extensive simulation study suggests that the method works well. Finally, we apply the method to a set of real interval-censored data that motivated this study.

Intramolecular Enantiomerism in S(+)2,2-dimethyl -1,3-dioxolane-4-methanol: The Interpretation of Raman Optical Activity Intensity.

A bond polarizability algorithm was developed and applied to interpret the Raman optical activity (ROA) intensity. It is demonstrated that for the chiral molecule such as S(+)2,2-dimethyl-1,3-dioxolane-4-methanol there exists approximate (or symmetry breaking) mirror reflection that reverses the signs of the differential bond polarizabilities of the pair bond coordinates that are related to each other by the mirror reflection, just like that between the right and left enantiomers. The magnitude difference of the differential bond polarizabilities of the pair bond coordinates becomes smaller as they are farther away from the asymmetric atom. Hence, that the asymmetric atom (center) plays a central role in ROA is confirmed from a spectroscopic viewpoint. Meanwhile, the concept of intramolecular enantiomerism is proposed.

Regression analysis of informative current status data with the additive hazards model.

This paper discusses regression analysis of current status failure time data arising from the additive hazards model in the presence of informative censoring. Many methods have been developed for regression analysis of current status data under various regression models if the censoring is noninformative, and also there exists a large literature on parametric analysis of informative current status data in the context of tumorgenicity experiments. In this paper, a semiparametric maximum likelihood estimation procedure is presented and in the method, the copula model is employed to describe the relationship between the failure time of interest and the censoring time. Furthermore, I-splines are used to approximate the nonparametric functions involved and the asymptotic consistency and normality of the proposed estimators are established. A simulation study is conducted and indicates that the proposed approach works well for practical situations. An illustrative example is also provided.

Stereostructural implication by the differential bond polarizability: ROA intensity study of chiral s 2-amino 1-propanol.

The bond polarizability and differential bond polarizability are introduced to interpret the Raman and Raman optical activity (ROA) intensities, calculated by the ab initio method. Chiral S 2-amino 1-propanol is taken as a model molecule. Through these bond polarizabilities, we observe that symmetric and antisymmetric coordinates are, respectively, more significant in Raman and ROA. It is noted that in S 2-amino 1-propanol those bonds lying on a common plane share the same differential bond polarizability sign while that of the asymmetric C-H bond which protrudes out of the plane possesses the opposite sign. We conclude that ROA can offer more stereostructural implications than Raman and that the differential bond polarizability is potentially the appropriate parameter in interpreting the 3D configuration of a molecule.

Recent progress in hierarchical nanostructures for Ni-based industrial-level OER catalysts.

Exploring efficient and low-cost oxygen evolution reaction (OER) electrocatalysts reaching the industrial level current density is crucial for hydrogen production via water electrolysis. In this feature article, we summarize the recent progress in hierarchical nanostructures for the industrial-level OER. The contents mainly concern (i) the design of a hierarchical structure; (ii) a Ni-based hierarchical structure for the industrial current density OER; and (iii) the surface reconstruction of the hierarchical structure during the OER process. The work provides valuable guidance and insights for the manufacture of hierarchical nanomaterials and devices for industrial applications.

Localized surface plasmon resonance (LSPR) excitation on single silver nanoring with nanoscale surface roughness.

With the expansion of the application of high-sensitivity Surface-enhanced Raman scattering (SERS) technique, micro SERS-active substrates with rich optical properties and high-level functions are desired. In this study, silver nanorings with nanoscale surface roughness were fabricated as a new type of enclosed quasi-2D micro-SERS-active substrate. Highly-crystalline spherical and hemispherical silver nanoprotrusions were densely and uniformly distributed over the entire surface of the nanorings. The SERS signals were significantly enhanced on the roughened silver nanorings which were mainly derived from the maximal localized surface plasmon resonance (LSPR) points at the junctions between adjacent coupled nanoprotrusions on the roughened nanorings. The mapping image shows a uniform and intense LSPR enhancement over the nanorings, owing to the uniform and dense distribution of silver nanoprotrusions and the resulting uniform distribution of maximal LSPR points on the roughened nanorings. The dark-field spectra further indicated that the single roughened silver nanoring had significant LSPR enhancement, a wide LSPR frequency-range response, and adaptability for SERS enhancement. Notably, both the measured and simulated results demonstrate that the maximal LSPR enhancement at the junctions between the nanoprotrusions, which are distributed on the inner surface of the silver nanoring, is higher than that on the outer surface because of the plasmon-focusing effect of the enclosed silver nanoring, which leads to the lateral asymmetrical distribution of LSPR intensity, indicating more LSPR and SERS features. These results indicate that single roughened silver nanorings exhibit excellent performance as a new type of enclosed quasi-2D silver nanoring micro-SERS-active substrate, microzone LSPR catalysis, and micro/nanodevices.