Search

This work reveals the origin of PL evolution of InSe flake induced by weak and strong laser irradiation and provides a reliable experimental supplement to the photo oxidation study of InSe and opens up a new avenue to regulate the PL of InSe.

To evaluate the predictive value of gadoxetic acid-enhanced MRI features (focused on Liver Imaging Reporting and Data System (LI-RADS) v2018 features and non-LI-RADS imaging features) for microvascular invasion (MVI) of hepatocellular carcinoma (HCC).From October 2018 to December 2020, 134 patients who underwent gadoxetic acid-enhanced MRI with a pathological diagnosis of HCC after hepatectomy were enrolled in this retrospective study. Two radiologists assessed the pre-hepatectomy LI-RADS v2018 imaging features and non-LI-RADS features to identify independent predictors of MVI of HCC with a logistic regression model.Four MRI features were found to be independent predictors of MVI: corona enhancement [odds ratio (OR) 5.787; 95% confidence interval (CI) 1.180, 28.369; p = 0.030], mosaic architecture (OR 7.097; 95% CI 1.299, 38.783; p = 0.024), nonsmooth tumor margin (OR 13.131; 95% CI 3.950, 43.649; p 0.001), and peritumoral hypointensity on hepatobiliary phase (HBP) (OR 33.123; 95% CI 2.897, 378.688; p = 0.005). When one of four imaging features was present, the sensitivity was 93.2% (41/44), and the specificity was 71.1% (64/90).The four imaging features including corona enhancement, mosaic architecture, nonsmooth tumor margin, and peritumoral hypointensity on HBP can be used as preoperative imaging biomarkers for predicting MVI in patients at high risk for HCC. When one of the four imaging features is present, MVI can be predicted with a sensitivity 90%.

It is essential to release annealing induced strain during the crystallization process to realize efficient and stable perovskite solar cells (PSCs), which does not seem achievable using the conventional annealing process. Here we report a novel and facile thermal gradient assisted crystallization strategy by simply introducing a slant angle between the preheated hot plate and the substrate. A distinct crystallization sequence resulted along the in-plane direction pointing from the hot side to the cool side, which effectively reduced the crystallization rate, controlled the perovskite grain growth, and released the in-plane tensile strain. Moreover, this strategy enabled uniform strain distribution in the vertical direction and assisted in reducing the defects and aligning the energy bands. The corresponding device demonstrated champion power conversion efficiencies (PCEs) of 23.70% and 21.04% on the rigid and flexible substrates, respectively. These highly stable rigid devices retained 97% of the initial PCE after 1097 h of storage and more than 80% of the initial PCE after 1000 h of continuous operation at the maximum power point. This novel strategy opens a simple and effective avenue to improve the quality of perovskite films and photovoltaic devices via strain modulation and defect passivation.

Substrates provide the necessary support for scientific explorations of numerous promising features and exciting potential applications in two-dimensional (2D) transition metal dichalcogenides (TMDs). To utilize substrate engineering to alter the properties of 2D TMDs and avoid introducing unwanted adverse effects, various experimental techniques, such as high-frequency Raman spectroscopy, have been used to understand the interactions between 2D TMDs and substrates. However, sample-substrate interaction in 2D TMDs is not yet fully understood due to the lack of systematic studies by techniques that are sensitive to 2D TMD-substrate interaction. This work systematically investigates the interaction between tungsten disulfide (WS2) monolayers and substrates by low-frequency Raman spectroscopy, which is very sensitive to WS2-substrate interaction. Strong coupling with substrates is clearly revealed in chemical vapor deposition (CVD)-grown monolayer WS2 by its low-wavenumber interface mode. It is demonstrated that the enhanced sample-substrate interaction leads to tensile strain on monolayer WS2, which is induced during the cooling process of CVD growth and could be released for monolayer WS2 sample after transfer or fabricated by an annealing-free method such as mechanical exfoliation. These results not only suggest the effectiveness of low-frequency Raman spectroscopy for probing sample-substrate interactions in 2D TMDs, but also provide guidance for the design of high-performance devices with the desired sample-substrate coupling strength based on 2D TMDs.

We aimed to investigate the role of the quantitative parameters of dual-energy computed tomography (DECT) in evaluating patients with hepatocellular carcinoma (HCC) treated by transarterial chemoembolization (TACE). We retrospectively identified 80 HCC patients (mean age, 56 years; 61 men) treated by TACE who received contrast-enhanced DECT and were retreated by TACE within 7 days between November 2018 and December 2019. Taking digital subtraction angiography (DSA) and CT images as reference standard, two readers measured and calculated the values of normalized iodine concentration at arterial phase (NICAP), normalized iodine concentration at portal venous phase (NICPP), iodine concentration difference (ICD), arterial iodine fraction (AIF) and slope of the spectral Hounsfield unit curve (λHu) by placing matched regions of interests (ROIs) within the tumor active area (TAA), adjacent normal hepatic parenchyma (ANHP) and tumor necrotic area (TNA). Differences between the parameters were analyzed by the Kruskal–Wallis H test. Receiver operating characteristic analysis of the parameters performance in differentiating the three tissues types was performed. AIF exhibited a good performance in distinguishing TAA (0.93 ± 0.31) and ANHP (0.18 ± 0.14), the areas under the receiver operating characteristic curve (AUC) was 0.989, while the λHu exhibited an excellent performance in distinguishing TAA (3.32 ± 1.24) and TNA (0.29 ± 0.27), with an AUC of 1.000. In conclusion, quantitative DECT can be effectively used to evaluate the tumor viability in HCC patients treated by TACE.

The development of quantitative metabolomics approaches for future standardized and translational applications has become increasingly important. Data-independent targeted quantitative metabolomics (DITQM) is a newly proposed method providing ion pair information on 1324 metabolites. However, the quantification of more than 1000 metabolites in large sample sizes has still not been implemented. In this study, on the basis of the DITQM concept, scheduled multiple reaction monitoring (MRM) methods for both high-abundant and low-abundant metabolites were established to broaden the quantification coverage, and an open-source program "Quanter_1.0" was coded to facilitate efficient data handling. Our results demonstrated that 1015 metabolites in human plasma met the quantitative requirements and could be relatively determined in an effective manner. The method was then applied to a large-scale sample study of lung cancer consisting of three distinct analytical batches. It was obvious that data quality that originated from quantitative metabolomics was improved, with substantially lower intra- and inter-batch data variation, resulting in a more effective multivariate statistical model. Finally, 26 potential biomarkers of lung cancer were discovered. Collectively, our approach provides a promising tool for quantitative metabolomics research involving large-scale sample sizes and clinical application.

Accurate, reproducible, noninvasive determination of left ventricular (LV) volumes and ejection fraction (EF) is important for clinical assessment, selection of therapy, and serial monitoring of patients with hypertrophic cardiomyopathy (HCM). Current clinical Two-dimensional echocardiography (2DE) may cause inaccurate measurements in patients with HCM because of their asymmetric ventricles and limitations of 2DE technology. Three-dimensional echocardiography (3DE) have demonstrated significantly greater accuracy. However, the time-consuming workflow limits the clinical utility of 3DE.We aim to compare the performance of a novel automated 3DE system (HeartModel, Philips Healthcare) with 2DE in a group of patients with HCM. Cardiac magnetic resonance (CMR) was reference standard.Fifty-three patients with HCM were examined by automated 3DE (3DEA), two-dimensional biplane Simpson's method (2DBP), manual 3DE method, and CMR, respectively. For patients with poor automated quantification, manual correction was performed. The Pearson correlation coefficient and Bland-Altman analysis and paired Student t tests were used to assess inter-technique agreement.3DEA measurements with contour editing correlate well with CMR and manual 2DE and 3DE measurements (r = .80-.96). The analysis time of 3DEA was shorter than that of 2DBP (3DEA, 141 ± 15s; 2DBP, 174 ± 17 s). Inter-observer variability was reduced significantly with use of 3DEA.Compared with current clinical 2DBP method, the analysis time of automated 3DE was much shorter with the added benefit of enhanced accuracy and reproducibility. Patients with asymmetric chamber may rely more on the timesaving automated 3DE quantification in the future.

Background Lysophosphatidylcholine (LPC) plays pivotal roles in several physiological processes and their disturbances are closely associated with various disorders. In this study, we described the development and validation of a reliable and simple flow injection analysis–tandem mass spectrometry (FIA‐MS/MS)‐based method using dried blood spots (DBS) for quantification of four individual LPC (C20:0, C22:0, C24:0, and C26:0). Methods Lysophosphatidylcholines were extracted from 3.2 mm DBS with 85% methanol containing 60 ng/ml internal standard using a rapid (30 min) and simple procedure. The analytes and the internal standard were directly measured by triple quadrupole tandem mass spectrometry in multiple reactions monitoring mode via positive electrospray ionization. Results Method validation results showed good linearity ranging from 50 to 2000 ng/ml for each LPC. Intra‐ and inter‐day precision and accuracy were within the acceptable limits at four quality control levels. Recovery was from 70.5% to 107.0%, and all analytes in DBS were stable under assay conditions (24 h at room temperature and 72 h in autosampler). The validated method was successfully applied to assessment of C20:0‐C26:0LPCs in 1900 Chinese neonates. C26:0‐LPC levels in this study were consistent with previously published values. Conclusion We propose a simple FIA‐MS/MS method for analyzing C20:0‐C26:0LPCs in DBS, which can be used for first‐tier screening., We proposed a reliable and simple flow injection analysis–tandem mass spectrometry (FIA‐MS/MS)‐based method using dried blood spots (DBS) for quantification of four individual LPC (C20:0, C22:0, C24:0, and C26:0). The elaborated method was successfully applied to assessment of C20:0‐C26:0LPCs in 1900 Chinese neonates.

Realization of remote wearable health monitoring (RWHM) technology for the flexible photodiodes is highly desirable in remote-sensing healthcare systems used in space stations, oceans, and forecasting warning, which demands high external quantum efficiency (EQE) and detectivity in NIR region. Traditional inorganic photodetectors (PDs) are mechanically rigid and expensive while the widely reported solution-processed mixed tin-lead (MSP) perovskite photodetectors (PPDs) exhibit a trade-off between EQE and detectivity in the NIR region. Herein, a novel functional passivating antioxidant (FPA) strategy has been introduced for the first time to simultaneously improve crystallization, restrain Sn

Objective To evaluate the relationship between pancreatic parenchyma loss and early postoperative hyperglycemia in patients with benign pancreatic diseases. Methods A total of 171 patients with benign pancreatic tumors or chronic pancreatitis, whose preoperative fasting blood glucose (FBG) was normal and who underwent partial pancreatectomy were reviewed. The pancreatic volume was measured by CT imaging before and after the operation. According to their different pancreatic resection volume (PRV), 171 patients were divided into five groups: < 30%, 30%–39%, 40%–49%, 50%–59%, and ≥ 60%. The correlation between the PRV and postoperative FBG was investigated. According to the postoperative FBG value, the patients were divided into a hyperglycemia group (HG) and nonhyperglycemia group (non-HG) to explore the best cutoff value of the PRV between the two groups. Results There were significant differences in the postoperative FBG among the five groups (PRV < 30%, 30%–39%, 40%–49%, 50%–59%, and ≥ 60%). The PRV was positively correlated with postoperative FBG in the benign tumor group and chronic pancreatitis group (R = 0.727 and 0.651, respectively). ROC curve analysis showed that the best cutoff value of the PRV between the HG (n = 84) and non-HG (n = 87) was 39.95% with an AUC = 0.898; the sensitivity was 89.29%, and the specificity was 82.76%. Conclusion There was a linear positive correlation between the postoperative FBG level and PRV. Patients with a PRV ≥ 40% are more likely to develop early postoperative hyperglycemia.

Predicting the runtime of distributed iterative jobs can help reduce the deployment cost of clusters and optimize their resource allocation and scheduling strategies, but the runtime depends on various factors which are difficult to be acquired before execution. In this paper, we propose a generalized online prediction method for the runtime of distributed iterative jobs, which is centered on a series of online machine learning models. The method consists of three phases: 1) estimating the number of iterations for the current iterative job. 2) predicting the runtime metrics of each iteration by an online polynomial regression model. 3) Runtime metrics sequence is analyzed using an LSTM trained with online learning to predict the runtime of each iteration. We conducted experiments on typical Flink iterative jobs, and the experimental results show that our method improves the accuracy by 4.79% compared to the state-of-the-art methods, while for the improvement in accuracy for delta iterative jobs is even more than 15%.

Background To study the prevalence of the exposure of pregnant women to antimicrobials, a sensitive and reliable liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method was developed and validated to determine nine antimicrobials, namely sulfadimidine, sulfapyridine, sulfadiazine, sulfathiazole, ofloxacin, ciprofloxacin, norfloxacin, tetracycline, and lincomycin, in human serum. Methods The sample preparation procedure included protein precipitation followed by a cleanup step with solid phase extraction (SPE). Separation was carried out using a CORTECS T3 column (100 × 2.1 mm, 2.7 µm) by gradient elution with a runtime of 8.0 min. Detection was performed on a triple quadruple tandem mass spectrometer with scheduled multiple reaction monitoring (sMRM) in positive ion scan mode. Results The calibration curves were linear over the concentration range of 0.5–50 ng/ml, and the limit of quantitation was between 0.01 and 0.2 ng/ml. For each level of quality control samples, the inter‐ and intra‐assay precision values were less than 12.0%, and the accuracy ranged from 86.1% to 109.0%. No significant matrix effect or carryover was observed. The antimicrobials of interest were stable under all investigated conditions. The validated method was applied to analyze clinical samples from pregnant women in China, and 10 out of 500 samples showed the presence of antimicrobial residues. Moreover, compared with the time‐resolved fluoro‐immunoassay (TRFIA) method, the developed method showed greater sensitivity and specificity. Conclusion This study provides a simple and rapid LC‐MS/MS method for the simultaneous measurement of nine antimicrobials in serum samples, which could be a useful tool in clinical utilization., We proposed a simple SPE LC‐MS/MS method for the analysis of nine antimicrobials in serum. The elaborated method was applied to investigate the exposure of antimicrobials in Chinese pregnant women, and the results have been compared with those obtained from TRFIA method.

Background Phe-restricted diets have been the basis of therapy for phenylketonurics; however, little is known how this treatment effects homeostasis of other important amino acids. This study aimed to describe blood amino acid patterns in neonates with phenylketonuria (PKU) and identify any effects of Phe restriction on these patterns in young children.Methods Neonate group (age 0-4 weeks): 45 PKU patients, 45 age-/sex-matched controls without PKU; 1-4 year-old group: 27 diet-treated PKU patients, 27 age-/sex-matched children without PKU. Concentrations of 11 amino acids were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS) performed on dried blood spots.Results Elevated blood phenylalanine (Phe), arginine (Arg), citrulline (Cit), valine (Val) and methionine (Met) concentrations were observed in PKU neonates relative to controls (Phe, Arg, Cit, Val: P < 0.001; Met: P < 0.05), of which Phe, Arg, and Met levels could be either partially or completely restored with dietary intervention. Diet had no effect on elevated Cit and Val. Decreased blood tyrosine (Tyr) and proline (Pro) concentrations were observed in PKU neonates compared to controls (P < 0.001). Both amino acids could be near completely restored to normal with dietary treatment. No significant differences in alanine (Ala), leucine (Leu), ornithine (Orn) and glycine (Gly) concentrations were found in the PKU neonates and 1-4 year-old groups (P > 0.05).Conclusions Blood amino acid homeostasis is disrupted in neonates and young children with PKU. Although dietary intervention adjusts amino acid homeostasis in the direction of a healthy equilibrium, complete restoration is not achieved. This persistent disruption may represent a clinically significant barrier to achieving the best possible therapy for those with PKU. Use of laboratory technologies such as LC-MS/MS enable characterization of persistent blood amino acid disequilibrium in the treated phenylketonuric. Testing of this kind presents opportunity for customized treatment feedback that may allow even greater optimization of therapy for neonates and children with PKU.

Two-dimensional van der Waals heterostructures (vdWHs) are drawing growing interest in the investigation of their valley polarization properties of localized excitons. However, most of the reported vdWHs were made by micro-mechanical peeling, limiting their large-scale production and practical applications. Furthermore, the circular polarization characters of localized excitons in WSe

Background: Preeclampsia (PE) is one of the main causes of maternal and fetal morbidity and mortality worldwide. This study was aimed to explore the potential metabolic alterations in women diagnosed with PE and reveal the underlying pathogenesis of disease.Methods: Healthy pregnant women and patients diagnosed with PE were recruited from August 2017 to February 2018. The metabolomic analysis of serum (n=90) and placenta (n=9) samples collected from the two groups were performed with the high performance liquid chromatography coupled with quadrupole-time-of light mass spectrometry (HPLC-QTOF-MS).Results: In serum, 16 metabolites that were present in different concentrations between the two groups were identified, of which pyroglutamic acid (pGlu), methionine, glutamine and taurocholic acid may be used as potential PE diagnosis biomarkers with the area under ROC curve of 0.901, 0.909, 0.892 and 0.873 respectively. Furthermore, the metabolic pathways analysis with differential metabolites in serum and placenta samples showed that linoleic acid and alpha- linolenic acid metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, D-glutamine/D-glutamate metabolism, phenylalanine metabolism, glutathione (GSH) metabolism and tryptophan metabolism were significantly altered and might be involved in PE pathogenesis.Conclusions: These results showed the altered metabolic pathways could contribute to the pathophysiologic mechanisms of PE.

Interlayer excitons (IX) are produced by the spatially separated electron-hole pairs due to the robust Coulomb interactions in van der Waals transition metal dichalcogenide (TMDC) heterostructures (HS

Targeted quantification and untargeted global profiling are the two mainstream approaches, a merging of which could provide enhanced analytical potential in metabolomics research. Here, a simultaneous targeted quantification and untargeted metabolomics (STQUM) strategy was developed for more efficient, accurate and comprehensive metabolomics research by using ultra-high-performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UPLC-HRMS/MS). First, we selected 110 cancer-related metabolites as targets and established a dual LC sequential separation method for simultaneous analysis of strong and weak polar metabolites. In order to achieve efficient acquisition for synchronous qualitative and quantitative analysis, high-resolution, data-dependent parallel reaction monitoring (PRM) method and data-independent all ion fragmentation (AIF) method were established. Their performance in targeted confirmation and quantification, and untargeted analysis were systematically investigated and assessed. In total, 78 metabolites were confidently confirmed in positive ion mode in both PRM and AIF assays, in which 73 metabolites can be accurately quantified. In addition, simultaneously untargeted profiling of 4651 features of high reliability and validity were achieved. Both AIF and PRM methods revealed high confidence, sensitivity and accuracy. In the STQUM approach, another 15 metabolites could be accurately quantified in negative ion mode. The method offers a new perspective for merging the hypothesis-based targeted quantitative validation and untargeted biomarkers discovery in one run for improved analysis efficiency and integrity.

The processes of single droplet freezing, frost accumulation and droplets flooding during condensation were analyzed and compared for surfaces of different morphologies. Four samples were first fabricated – a micro-cubes silicon, a micro-cylinders silicon, a hierarchically-structured silicon and a smooth silicon. After measuring the static contact angles and roll angles, the sessile water droplet freezing and frost accumulation under a series of surface temperature were studied. The droplets condensation processes were for the first time compared through environmental scanning electron microscopy (ESEM). The results showed that the droplet freezing time on hierarchically-structured silicon was 4 times longer than that of uncoated silicon. Micro-pillared and hierarchically-structured silicons could minimize the frost thickness only in the initial stage of frost formation and had quite different frost growth patterns. The ESEM images can facilitate explain the different patterns of freezing and frosting on micro-pillared and hierarchically-structured samples.

Gliomas are the most common and lethal primary malignant brain tumors. Recent studies implicate an important role for a rare population of glioma stem cells (GSCs) in glioma maintenance and recurrence. New therapeutic strategies are desperately needed requiring insights into the biological and molecular mechanisms underlying the self-renewal and differentiation of GSCs. We now investigate the metabolic signatures of three glioma cell lines with different stemness using a liquid chromatography-mass spectrometry (LC-MS)-based metabolomics approach. Cellular metabolites differentially expressed in U87MG stem-like cells (SLCs) relative to U87 malignant glioma cells (GCs) and U87MG stem-like cell differentiation cells (SLCDCs) were identified. The specific and significant alterations including nucleotide metabolism, glycerophospholipid metabolism, glutathione metabolism, carnitine metabolism and tryptophan metabolism were characterized. Cell function assays were further used to evaluate the self-renewal ability of SLCs treated with differential metabolites, indicating that these metabolites are involved in the maintenance of stemness. The results provide valuable information on the association of the significantly altered metabolites and metabolic pathways with SLC self-renewal and differentiation.

In this paper, we focus on coordinated motion planning of dual-arm robot. The kinematics model of the robotic arm is established by Denavit-Hartenberg (D-H) coordinate method and the mathematical model of the cooperative motion planning problem is established. The rapidly-exploring random trees (RRT) algorithm and the deep deterministic policy gradient (DDPG) algorithm are used to carry out dual-arm coordinated motion planning, respectively. The simulation results show that these algorithms can effectively complete the robot arm motion planning task, but the RRT improved algorithm cannot balance the planning efficiency and result optimization. Compared with the RRT algorithm, the DDPG algorithm trains the model through continuous trial and error to optimize its planning strategy. The trained model can be used to obtain an optimized path and it can ensure the efficiency of the planning with the optimized strategy.

A cellulose sulfonate catalyst (HS-cellulose sulfonate) with high stability, excellent catalytic activity and high acidity value (about 1.55 mmol g−1) was successfully prepared by SO3 gas phase sulfonation. The basic morphology and nanostructure of the catalyst were determined by HRTEM, XRD, IR, TG, etc. In addition, the catalyst was applied to the catalytic reaction of a dihydroquinazolinone derivative and a xanthene compound, and very valuable results were obtained. The development and preparation of cellulose sulfonate catalysts provide a good approach for the development and application of cellulose, and also an important application of green organic catalytic synthesis methodology.

In this research, the effects of black silicon and two-stage black silicon surface structures on the characteristics of wetting, icing process of a single water droplet, and frost accumulation under natural convection conditions were investigated. Black silicon and two-stage black silicon surfaces were first designed and fabricated, and then examined by means of scanning electron microscopy (SEM). Wetting behavior was measured by contact angle measurement system. The icing and frosting processes were acquired through high-speed photography. The test surfaces were cooled down from room temperature to well below 0 °C by circulating ethyl alcohol via a constant temperature system. The results show that compared with uncoated silicon, black silicon and two-stage black silicon surfaces can largely increase the surface hydrophobicity, reduce the freezing thickness deformation and show anti-frosting performance. This study provides a new type of hydrophobic surface structure and plays an important role in designing anti-icing/anti-frosting surfaces for practical applications.

The excitonic effects in two-dimensional transition metal dichalcogenides and their heterostructures have been extensively investigated. Significantly, the moire excitons, induced by a moire superlattice in a twisted heterostructure, have triggered tremendous attention, demonstrating the practicability of artificial excitonic crystals. Besides, recent works have shown that the excitonic states in homostructures also exhibit novel properties worthy of further development. Here, we present a tear-and-stack technique for fabricating a regular or a twisted homostructure. Such a strategy was utilized to reassemble a monolayer WSe2 into a twisted homostructure, and various excitons from this structure have been identified in the photoluminescence spectra. Interestingly, the unusual equidistant splitting was first observed in the defect-bound excitons. It is believed that this phenomenon is attributed to the various defect states and the local stacking patterns. This interpretation is supported by theoretical calculations, which show the dependence of the energy band structure on different defect states and local stacking patterns. These unconventional defect-bound excitons are key building blocks in the research of homostructures that highlight the feasibility of artificially manipulating local excitons for practical applications.

Two-dimensional van der Waals heterostructures (vdWHs) are drawing growing interest in the investigation of their valley polarization properties of localized excitons. However, most of the reported vdWHs were made by micro-mechanical peeling, limiting their large-scale production and practical applications. Furthermore, the circular polarization characters of localized excitons in WSe2/WS2 heterostructures remain elusive. Here, a bidirectional-flow physical vapor deposition technique was employed for the synthesis of the WSe2/WS2 type-II vertical heterostructures. The interfaces of such heterojunctions are sharp and clean, making the neutral excitons of the constituent layers quenched, which significantly highlights the luminescence of the local excitons. The circular polarization of localized excitons in this WSe2/WS2 heterostructure was demonstrated by circularly-polarized PL spectroscopy. The degree of the circular polarization of the localized excitons was determined as 7.17% for σ- detection and 4.78% for σ+ detection. Such local excitons play a critical role in a quantum emitter with enhanced spontaneous emission rate that could lead to the evolution of LEDs. Our observations provide valuable information for the exploration of intriguing excitonic physics and the applications of innovative local exciton devices.

Interlayer excitons (IX) are produced by the spatially separated electron-hole pairs due to the robust Coulomb interactions in van der Waals transition metal dichalcogenide (TMDC) heterostructures (HSS). IX is characterized by a larger binding energy, and its lifetime is orders of magnitude longer than that of the direct excitons, providing a significant platform for the manufacture of long-lived exciton devices and the exploration of exciton quantum gas. However, the studies are restricted to the single interlayer exciton, and the simultaneous capture and study of double IX remain challenging in the WSe2/WS2 HS. Here, we demonstrate the existence of double indirect IX in the WSe2/WS2 HS with the emission centers at 1.4585eV (∼25.9meV wide) and 1.4885 eV (∼14.4 meV wide) at cryogenic temperature. Interestingly, the intensities of the double IX emission peaks are almost equal, and the energy difference between them is in a good agreement with the cleavage value of the WS2 conduction band (CB). Additionally, diverse types of excitons in the individual materials were successfully observed in the PL spectra at 8 K. Such unique double IX features, in combination with excellent exciton identification, open up new opportunities for further investigations for new physical properties of TMDCs and explorations for the technological innovation of exciton devices.

The discovery and identification of reliable disease biomarkers and relevant disrupted metabolic pathways is still a major challenge in metabolomics. Here, we proposed a biotransformation-based metabolomics profiling method to identify reliable disease biomarkers by simultaneous quantitation and qualification of cancer-related metabolites and their metabolic pathways via liquid chromatography-tandem mass spectrometry (LC-MS/MS). The approach was based on selecting a subset of known cancer-related metabolites from our previous metabolomics work, cancer research literature and biological significance. The metabolic profiling of pathway-related metabolites was developed by predicted multiple reaction monitoring (MRM) of ion pairs based on their chemical structures and biotransformation. Then, a high-throughput quantitative method was established. Overall, this approach enables the sensitive and accurate detection of cancer-related metabolites and the identification of other relevant metabolites, which facilitates better data quality and in-depth investigation of dysregulated metabolic pathways. As a proof of concept, the approach was applied to a small-cell lung cancer (SCLC) study. The results showed that 43 metabolites were significantly changed, and arginine metabolism was apparently disturbed, which proved the proposed approach could be a powerful tool for discovering reliable disease biomarkers and aberrant metabolic pathways.

Water droplet freezing and melting on three micro- or hierarchically-structured silicon surfaces and a smooth silicon wafer were studied experimentally. The surface temperature was kept at −13.8 °C during freezing and increased gradually to room temperature after turning off the bath circulator. The freezing behaviors including the freezing delay, solidification front movement, and the droplet profile were obtained through the photographic method. The results show that the tiny black silicon particles on hierarchical structures facilitate a longer freezing delay. The solidification stage lasted for 5–17 s depending on the surface structures, during which the freezing rate was larger in the initial seconds. Droplet on three micro-structured surfaces formed a tip with the angle of 122 ± 2°, smaller than that on the smooth silicon which was 136 ± 3°. The melting onset temperature for samples 1–3 was about 4.4 °C while melting happened on smooth silicon needed a smaller degree of superheat.

Usually, insufficient intratumoral concentration of therapeutic drugs is one of the reasons for tumor treatment failure. However, little is known about intratumoral distribution of bromocriptine in non-responding prolactinomas because of extremely low drug concentration and small prolactinoma tissue samples. In this study, a sensitive, rapid and high-throughput quantitative bioanalytical method has been established by using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for the determination of bromocriptine at trace level in human prolactinoma tissue. As little as 20 mg (wet weight) tissue sample was required and total analysis time was 6 min in this method. The assay quantifies over a linear range of 50 fg/mg to 5 pg/mg, and has a 25 fg/mg limit of detection at a signal/noise ratio of 3. This validated method was successfully used to quantitatively determine bromocriptine in clinical post-operative bromocriptine-sensitive and -resistant prolactinomas. The results revealed bromocriptine concentration in resistant prolactinomas (0.49-1.25 pg/mg) was significantly higher than that in sensitive prolactinomas (0.057-0.47 pg/mg). These results provided direct evidence to demonstrate the reseaon for failure of bromocriptine treatment in some patients with prolactinoma was "intrinsic" tumor (cell) resistence, rather than insufficient drug concentration in tumor tissue. Additionaly, this HPLC-MS/MS method has been shown to be suitable for bromocriptine analysis in small amount tissue sample and could be adapted for therapeutic drug monitoring of other clinical medicine.