Metabolomics assisted by transcriptomics analysis to reveal metabolic characteristics and potential biomarkers associated with treatment response of neoadjuvant therapy with TCbHP regimen in HER2 + breast cancer.

BACKGROUND: This study aimed to explore potential indicators associated with the neoadjuvant efficacy of TCbHP regimen (taxane, carboplatin, trastuzumab, and pertuzumab) in HER2 + breast cancer (BrCa) patients. METHODS: A total of 120 plasma samples from 40 patients with HER2 + BrCa were prospectively collected at three treatment times of neoadjuvant therapy (NAT) with TCbHP regimen. Serum metabolites were analyzed based on LC-MS and GC-MS data. Random forest was used to establish predictive models based on pre-therapeutic differentially expressed metabolites. Time series analysis was used to obtain potential monitors for treatment response. Transcriptome analysis was performed in nine available pre­therapeutic specimens of core needle biopsies. Integrated analyses of metabolomics and transcriptomics were also performed in these nine patients. qRT-PCR was used to detect altered genes in trastuzumab-sensitive and trastuzumab-resistant cell lines. RESULTS: Twenty-one patients achieved pCR, and 19 patients achieved non-pCR. There were significant differences in plasma metabolic profiles before and during treatment. A total of 100 differential metabolites were identified between pCR patients and non-pCR patients at baseline; these metabolites were markedly enriched in 40 metabolic pathways. The area under the curve (AUC) values for discriminating the pCR and non-PCR groups from the NAT of the single potential metabolite [sophorose, N-(2-acetamido) iminodiacetic acid, taurine and 6-hydroxy-2-aminohexanoic acid] or combined panel of these metabolites were greater than 0.910. Eighteen metabolites exhibited potential for monitoring efficacy. Several validated genes might be associated with trastuzumab resistance. Thirty-nine altered pathways were found to be abnormally expressed at both the transcriptional and metabolic levels. CONCLUSION: Serum-metabolomics could be used as a powerful tool for exploring informative biomarkers for predicting or monitoring treatment efficacy. Metabolomics integrated with transcriptomics analysis could assist in obtaining new insights into biochemical pathophysiology and might facilitate the development of new treatment targets for insensitive patients.

Stimulated Raman Scattering Microscopy Reveals Aberrant Triglyceride Accumulation in Lymphatic Metastasis of Papillary Thyroid Carcinoma.

Lipid metabolic alterations are known to play a crucial role in cancer metastasis. As a key hub in lipid metabolism, intracellular neutral lipid accumulation in lipid droplets (LDs) has become a signature of aggressive human cancers. Nevertheless, it remains unclear whether lipid accumulation displays distinctive features in metastatic lesions compared to the primary ones. Here, we integrated multicolor stimulated Raman scattering (SRS) imaging with confocal Raman spectroscopy on the same platform to quantitatively analyze the amount and composition of LDs in intact human thyroid tissues in situ without any processing or labeling. Inspiringly, we found aberrant accumulation of triglycerides (TGs) in lymphatic metastases but not in normal thyroid, primary papillary thyroid carcinoma (PTC), or normal lymph node. In addition, the unsaturation degree of unsaturated TGs was significantly higher in the lymphatic metastases from patients diagnosed with late-stage (T3/T4) PTC compared to those of patients diagnosed with early-stage (T1/T2) PTC. Furthermore, both public sequencing data analysis and our RNA-seq transcriptomic experiment showed significantly higher expression of alcohol dehydrogenase-1B (ADH1B), which is critical to lipid uptake and transport, in lymphatic metastases relative to the primary ones. In summary, these findings unravel the lipid accumulation as a novel marker and therapeutic target for PTC lymphatic metastasis that has a poor response to the regular radioactive iodine therapy.

Quantification of Hepatic Steatosis on Dual-Energy CT in Comparison With MRI mDIXON-Quant Sequence in Breast Cancer.

OBJECTIVE: The study aimed to evaluate the correlation and diagnostic value of liver fat quantification in unenhanced dual-energy CT (DECT) using quantitative magnetic resonance imaging (MRI) mDIXON-Quant sequence as reference standard in patients with breast cancer. METHODS: Patients with breast cancer were prospectively recruited between June 2018 and April 2020. Each patient underwent liver DECT and MRI mDIXON-Quant examination. The DECT-fat volume fraction (FVF) and liver-spleen attenuation differences were compared with the MRI-proton density fat fraction using scatterplots, Bland-Altman plots, and concordance correlation coefficient. Receiver operating characteristic curves were established to determine the diagnostic accuracy of hepatic steatosis by DECT. RESULTS: A total of 216 patients with breast cancer (mean age, 50.08 ± 9.33 years) were evaluated. The DECT-FVF correlated well with MRI-proton density fat fraction ( r2 = 0.902; P < 0.001), which was higher than the difference in liver-spleen attenuation ( r2 = 0.728; P < 0.001). Bland-Altman analysis revealed slight positive bias; the mean difference was 3.986. The DECT-FVF yielded an average concordance correlation coefficient of 0.677, which was higher than the difference of liver-spleen attenuation (-0.544). The DECT-FVF and the difference in liver-spleen attenuation both lead to mild overestimation of hepatic steatosis. The areas under the curve of DECT-FVF (0.956) were higher than the difference in liver-spleen attenuation (0.807) in identifying hepatic steatosis ( P < 0.001). CONCLUSIONS: Dual-energy CT-FVF may serve as a reliable screening and quantitative tool for hepatic steatosis in patients with breast cancer.

Correlation Between Preoperative and Postoperative Alignment and Kinematic Gait in Total Knee Arthroplasty.

Objective: Maintaining the lower limb in a neutral posture following total knee arthroplasty (TKA) has long been a concept maintained by operators. This study aimed to investigate the relationship between changes in lower limb alignment and the dynamics of knee gait before and after TKA to understand the impact of alignment on gait better and offer a theoretical foundation for correcting lower limb alignment in TKA. Methods: Our study included a group of 20 participants. The cohort consisted of 1 male and 19 females, 11 left and 9 right knees, ages 58 to 81. Using the Opti_Knee® Knee Motion Test System with infrared reflective markers and a high-speed camera, the step length and 6 degrees of freedom of the knee were recorded. Following that, we investigated the association between HKA angle and knee kinematic gait before and after surgery. Results: For preoperative HKA angles ranging from -28° to -3°, we observed increased step length, flexion-extension rotation, and varus-valgus rotation with an increase in HKA angle. Conversely, an increase in HKA angle from -3 ° to 15° corresponded with decreased step length, flexion-extension rotation, and varus-valgus rotation. An increase in HKA angle from 1° to 3° postoperatively increased step length, flexion-extension rotation, and varus-valgus rotation. In contrast, increasing the HKA angle from 3° to 5° resulted in less flexion-extension rotation. The flexion-extension rotation was at its maximum when the HKA angle was 3°. A 3° postoperative varus resulted in improved kinematic gait. Step length, varus-valgus rotation, and flexion-extension rotation increased with increasing HKA angle in the neutral alignment group. In contrast, the non-neutral alignment group exhibited decreased flexion-extension rotation as the HKA angle increased, while step length and varus-valgus rotation increased as the HKA angle increased. The varus-valgus rotation was statistically significant (P < .05) in the preoperative versus early postoperative period in the 6 degrees of freedom. Conclusions: A 3° varus alignment was found to have a superior postoperative knee kinematic gait, implying that a 3° varus alignment may be more suitable as a new gold standard for TKA than the traditional "0°" alignment. The neutral alignment group demonstrated a better knee kinematic gait than the non-neutral alignment group. During early postoperative walking, significant improvements in varus-valgus rotation were found in the 6 degrees of knee freedom.

Floquet Engineering of Nonequilibrium Valley-Polarized Quantum Anomalous Hall Effect with Tunable Chern Number.

Here, we propose that Floquet engineering offers a strategy to realize the nonequilibrium quantum anomalous Hall effect (QAHE) with tunable Chern number. Using first-principles calculations and Floquet theorem, we unveil that QAHE related to valley polarization (VP-QAHE) is formed from the hybridization of Floquet sidebands in the two-dimensional family MSi2Z4 (M = Mo, W, V; Z = N, P, As) by irradiating circularly polarized light (CPL). Through the tuning of frequency, intensity, and handedness of CPL, the Chern number of VP-QAHE is highly tunable and up to C = ±4, which attributes to light-induced trigonal warping and multiple-band inversion at different valleys. The chiral edge states and quantized plateau of Hall conductance are visible inside the global band gap, thereby facilitating the experimental measurement. Our work not only establishes Floquet engineering of nonequilibrium VP-QAHE with tunable Chern number in realistic materials but also provides an avenue to explore emergent topological phases under light irradiation.

Real-time evolution dynamics during transitions between different dissipative soliton states in a single fiber laser.

Various dissipative soliton solutions exist in the parameter space of mode-locked fiber lasers, including both coherent and incoherent pulses. Novel ultrafast laser designs can lead to distinctive dissipative soliton solutions formed by unique pulse shaping dynamics in the same cavity. However, transitionary states in between steady-state mode-locked regimes remain largely unexplored. Here, we investigate the intermediate transition dynamics in a versatile Tm-doped fiber laser capable of emitting both dissipative solitons with anomalous-dispersion and normal-dispersion pulse-shaping mechanisms by adjusting an intracavity polarization controller. Real-time pulse dynamics during mode-locking transitions are analyzed with a modified dispersive Fourier transform setup, illustrating characteristic pulse shaping mechanisms typically reserved for different dispersion regimes. Combined with a spectral intensity correlation analysis, the coherence evolution between two distinct mode-locked states is fully resolved for the first time.

Chiral-Flux-Phase-Based Topological Superconductivity in Kagome Systems with Mixed Edge Chiralities.

Recent studies have attracted intense attention on the quasi-2D kagome superconductors AV_{3}Sb_{5} (A=K, Rb, and Cs) where the unexpected chiral flux phase (CFP) associates with the spontaneous time-reversal symmetry breaking in charge density wave states. Here, commencing from the 2-by-2 charge density wave phases, we bridge the gap between topological superconductivity and time-reversal asymmetric CFP in kagome systems. Several chiral topological superconductor (TSC) states featuring distinct Chern numbers emerge for an s-wave or a d-wave superconducting pairing symmetry. Importantly, these CFP-based TSC phases possess unique gapless edge modes with mixed chiralities (i.e., both positive and negative chiralities), but with the net chiralities consistent with the Bogoliubov-de Gennes Chern numbers. We further study the transport properties of a two-terminal junction, using Chern insulator or normal metal leads via atomic Green's function method with Landauer-Büttiker formalism. In both cases, the normal electron tunneling and the crossed Andreev reflection oscillate as the chemical potential changes, but together contribute to plateau transmissions (1 and 3/2, respectively) that exhibit robustness against disorder. These behaviors can be regarded as the signature of a TSC hosting edge states with mixed chiralities.

Berry-Curvature Engineering for Nonreciprocal Directional Dichroism in Two-Dimensional Antiferromagnets.

In two-dimensional antiferromagnets, we find that the mixed Berry curvature can be attributed as the geometrical origin of the nonreciprocal directional dichroism (NDD), which refers to the difference in light absorption between opposite propagation directions. This Berry curvature is closely related to the uniaxial strain in accordance with the symmetry constraint, leading to a highly tunable NDD, whose sign and strength can be tuned via strain direction. We choose the lattice model of MnBi_{2}Te_{4} as a concrete example. The coupling between mixed Berry curvature and strain also suggests the magnetic quadrupole of the Bloch wave packet as the macroscopic order parameter probed by the NDD in two dimensions, which is distinct from the multiferroic order P×M or the spin toroidal and quadrupole order within a unit cell in previous studies. Our work paves the way for the Berry-curvature engineering for optical nonreciprocity in two-dimensional antiferromagnets.

One Pot Synthesis of Nanofiber-Coated Magnetic Composites as Magnetic Dispersive Solid-Phase Extraction Adsorbents for Rapid Determination of Tetracyclines in Aquatic Food Products.

A magnetic adsorbent based on a C-nanofiber (Fe3O4@C-NFs) nanocomposite was synthesized using a simple one-pot co-precipitation method. The characterized results showed that the obtained C-nanofiber-coated magnetic nanoparticles had many attractive features such as a large specific surface area and a highly interwoven and branched mesoporous structure, as well as distinguished magnetism. The nanocomposite was then used as an adsorbent in the magnetic solid phase extraction (MSPE) of four typical tetracyclines (oxytetracycline, tetracycline, chlortetracycline, and doxycycline) in aquatic products. The TCs in the extract were determined using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Experimental variables of MSPE, including the sorbent amount, pH condition, adsorption and desorption time, and desorption solvent, were investigated and optimized systematically. The method validation indicated that the developed method showed good linearity (R2 > 0.995) in the range of 1.0-200 ng/mL. The average recoveries at the spiked levels ranged from 90.7% to 102.7% with intra-day and inter-day relative standard deviations (RSDs, n = 6) ranging from 3.72% to 8.17% and 4.20% to 9.69%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) for the four kinds of TCs were 0.7 µg/kg and 2.0 µg/kg, respectively. Finally, MSPE based on C-nanofiber-coated magnetic nanoparticles was successfully applied to TC analysis in real aquatic products (grass carp, large yellow croaker, snakehead, mandarin fish, Penaeus vannamei, swimming crab, etc.). Compared with traditional extraction methods, the proposed method for TC analysis in aquatic products is more sensitive, effective, recyclable, and environmentally friendly.

Real-time observation of chaotic and periodic explosions in a mode-locked Tm-doped fiber laser.

We experimentally characterize the dynamics of soliton explosions in a transient chaotic state between a single and double pulsing state, as well as periodic explosions induced by soliton collisions in a dual wavelength soliton state. These explosions occurring in a thulium-doped linear fiber laser with net anomalous dispersion are characterized with real-time measurements based on a modified time-stretched dispersive Fourier transform method relying on second-harmonic generation.

Mesenchymal Stem Cell-Derived Exosome-Containing Linc00632 Regulates GATA Binding Protein-3 Expression in Allergic Rhinitis by Interacting with Enhancer of Zeste Homolog 2 to Inhibit T Helper Cell 2 Differentiation.

BACKGROUND: Allergic rhinitis (AR) is regarded as one of the most common allergic disease of nasal mucosa affecting many people worldwide. Long noncoding RNAs are critical modulators affecting AR progression, whereas the pathogenesis of Linc00632 in the development of AR remains unclear. METHODS: T helper cell 2 (Th2) differentiation of CD4+ T cells was measured by flow cytometry. Real-time quantitative PCR assay and Western blot were applied to determine the levels of RNA and proteins, respectively. The interleukin (IL)-4 and IL-13 levels were quantitatively assessed through ELISA. Subcellular fractionation was conducted to detect the cellular localization of Linc00632. RNA immunoprecipitation experiment was employed to validate the interaction relationship between Linc00632 and enhancer of zeste homolog 2 (EZH2). Chromatin immunoprecipitation assay was used for determination of protein-DNA interactions. RESULTS: The expression of Linc00632 was significantly decreased by 4 times in nasal mucosa of AR patients. Human umbilical cord mesenchymal stem cell-derived exosome dramatically inhibited Th2 differentiation, decreased GATA binding protein-3 (GATA-3) protein expressions and IL-4 levels by about 2 times in CD4+ T cells. Knockdown Linc00632 partially reversed the effects of exosomes on Th2 differentiation, IL-4 and IL-13 levels, and GATA-3 expression. Linc00632 overexpression could suppress Th2 differentiation of CD4+ T cells, reduced IL-4 and IL-13 levels, and GATA-3 expressions roughly 2 times. Linc00632 repressed the expression of GATA-3 by interacting with EZH2. GATA-3 overexpression partially reversed the effect of Linc00632 on Th2 differentiation of CD4+ T cells. CONCLUSION: Linc00632 acted as a suppression factor in Th2 differentiation by inhibiting the expression of GATA-3 via interacting with EZH2, which might provide a new insight for understanding the action mechanism of Linc00632 in AR.

A comparison between manual and artificial intelligence-based automatic positioning in CT imaging for COVID-19 patients.

OBJECTIVE: To analyze and compare the imaging workflow, radiation dose, and image quality for COVID-19 patients examined using either the conventional manual positioning (MP) method or an AI-based automatic positioning (AP) method. MATERIALS AND METHODS: One hundred twenty-seven adult COVID-19 patients underwent chest CT scans on a CT scanner using the same scan protocol except with the manual positioning (MP group) for the initial scan and an AI-based automatic positioning method (AP group) for the follow-up scan. Radiation dose, patient positioning time, and off-center distance of the two groups were recorded and compared. Image noise and signal-to-noise ratio (SNR) were assessed by three experienced radiologists and were compared between the two groups. RESULTS: The AP operation was successful for all patients in the AP group and reduced the total positioning time by 28% compared with the MP group. Compared with the MP group, the AP group had significantly less patient off-center distance (AP 1.56 cm ± 0.83 vs. MP 4.05 cm ± 2.40, p < 0.001) and higher proportion of positioning accuracy (AP 99% vs. MP 92%), resulting in 16% radiation dose reduction (AP 6.1 mSv ± 1.3 vs. MP 7.3 mSv ± 1.2, p < 0.001) and 9% image noise reduction in erector spinae and lower noise and higher SNR for lesions in the pulmonary peripheral areas. CONCLUSION: The AI-based automatic positioning and centering in CT imaging is a promising new technique for reducing radiation dose and optimizing imaging workflow and image quality in imaging the chest. KEY POINTS: • The AI-based automatic positioning (AP) operation was successful for all patients in our study. • AP method reduced the total positioning time by 28% compared with the manual positioning (MP). • AP method had less patient off-center distance and higher proportion of positioning accuracy than MP method, resulting in 16% radiation dose reduction and 9% image noise reduction in erector spinae.

Integrate Candidate Answer Extraction with Re-Ranking for Chinese Machine Reading Comprehension.

Machine Reading Comprehension (MRC) research concerns how to endow machines with the ability to understand given passages and answer questions, which is a challenging problem in the field of natural language processing. To solve the Chinese MRC task efficiently, this paper proposes an Improved Extraction-based Reading Comprehension method with Answer Re-ranking (IERC-AR), consisting of a candidate answer extraction module and a re-ranking module. The candidate answer extraction module uses an improved pre-training language model, RoBERTa-WWM, to generate precise word representations, which can solve the problem of polysemy and is good for capturing Chinese word-level features. The re-ranking module re-evaluates candidate answers based on a self-attention mechanism, which can improve the accuracy of predicting answers. Traditional machine-reading methods generally integrate different modules into a pipeline system, which leads to re-encoding problems and inconsistent data distribution between the training and testing phases; therefore, this paper proposes an end-to-end model architecture for IERC-AR to reasonably integrate the candidate answer extraction and re-ranking modules. The experimental results on the Les MMRC dataset show that IERC-AR outperforms state-of-the-art MRC approaches.

Extraskeletal Ewing sarcoma of thyroid gland: A case report. / ç”²çŠ¶è ºéª¨å¤–å°¤å› è‚‰ç˜¤1ä¾‹å¹¶æ–‡çŒ®å¤ä¹ .

Extraskeletal Ewing sarcoma is a rare event, and extraskeletal Ewing sarcoma of the thyroid gland is even rarer. It has non-specific clinical manifestation and difficulty in early diagnosis. The diagnosis mainly depends on histology and immunohistochemistry. It possesses the features of high malignancy, high rate of local recurrence, and distant metastasis. Currently, the aggressive multimodal treatment contains surgery, chemotherapy, and radiotherapy. This study presented a case of extraskeletal Ewing sarcoma arising in the thyroid gland of a 30-year-old woman, who presented with supraclavicular mass and sense of dysphagia obstruction in Department of Otolaryngology, Head and Neck Surgery, Second Xiangya Hospital, Central South University in 2018. Imaging studies demonstrated a cystic-solid mass in inferior of the left leaf of thyroid gland and in the posterior of the trachea and esophagus. The patient underwent localized tumor resection. The pathological diagnosis revealed that it was a small round cell tumor, and the immunohistochemistry results were considered to be extraskeletal Ewing sarcoma. Subsequently, the patient was given chemotherapy and local radiation therapy. There was no evidence of tumor recurrence or metastasis.

Effect of gastric cancer stem cell on gastric cancer invasion, migration and angiogenesis.

Purpose: Using the gastric cancer cell line SGC7901 and gastric cancer stem cell (CSC-G), we conducted this study to investigate the role of cancer stem cells in invasion, metastasis and tumor angiogenesis. Methods: Stem cell markers (OCT4, SOX2, C-Myc and Klf4) expression was detected by RT-PCR and Western blotting. The proliferation, migration, invasion abilities, L-OHP and 5-FU resistance, angiogenesis were assessed using in vitro spherical clone formation assays, plate cloning experiments, transwell migration, transwell invasion, drug resistance, scratch-wound migration, ring formation assay, and their tumorigenic and ability were assessed using a tumor formation experiment in mice. Results: Compared with the SGC7901, the expression of Oct4, Sox2, Klf4 and CD44 mRNA was significantly higher in CSC-G, the mRNA relative expression of E-cadherin in CSC-G was lower than SGC7901, while the expression of c-Myc did not significantly change. The proliferation, drug resistance, migration, and invasion abilities were significantly higher in CSC-G, and the tumorigenic ability in mice was also significantly higher. Conclusion: The proliferation, drug resistance, migration, invasion, and tumorigenic abilities of CSC-G significantly were higher than SGC7901. CSC-G plays important roles in proliferation, migration, invasion, and tumorigenicity.

Laparoscopic versus open approach in gastrectomy for advanced gastric cancer: a systematic review.

BACKGROUND: Additional studies comparing laparoscopic gastrectomy (LG) versus open gastrectomy (OG) for advanced gastric cancer (AGC) have been published, and it is necessary to update the systematic review of this subject. OBJECTIVE: We conducted the meta-analysis to find some proof for the use of LG in AGC and evaluate whether LG is an alternative treatment for AGC. METHOD: Randomized controlled trials (RCT) and high-quality retrospective studies (NRCT) compared LG and OG for AGC, which were published in English between January 2010 and May 2019, were search in PubMed, Embase, and Web of Knowledge by three authors independently and thoroughly. Some primary endpoints were compared between the two groups, including intraoperative time, intraoperative blood loss, harvested lymph nodes, first flatus, first oral intake, first out of bed, post-operative hospital stay, postoperative morbidity and mortality, rate of disease recurrence, and 5-year over survival (5-y OS). Besides, considering for this 10-year dramatical surgical material development between 2010 and 2019, we furtherly make the same analysis based on recent studies published between 2016 and 2019. RESULT: Thirty-six studies were enrolled in this systematic review and meta-analysis, including 5714 cases in LAG and 6094 cases in OG. LG showed longer intraoperative time, less intraoperative blood loss, and quicker recovery after operations. The number of harvested lymph nodes, hospital mortality, and tumor recurrence were similar. Postoperative morbidity and 5-y OS favored LG. Furthermore, the systemic analysis of recent studies published between 2016 and 2019 revealed similar result. CONCLUSION: A positive trend was indicated towards LG. LG can be performed as an alternative to OG for AGC.

Prognostic value of ZEB-1 in solid tumors: a meta-analysis.

BACKGROUND: Zinc-finger E-box binding homeobox 1 (ZEB-1) plays crucial roles in epithelial-to-mesenchymal transition during tumor carcinogenesis. Published studies have examined the potential value of ZEB-1 as a biomarker for the prognosis of cancer. Nevertheless, the prognostic significance of ZEB-1 in human solid tumor remains inconclusive. Therefore, we performed the present meta-analysis to evaluate the prognostic value of ZEB-1 in patients with solid tumors. METHODS: The 13 included studies (1616 patients) were exact electronic searched from Web of Science, PubMed and EBSCO until September 2018. Pooled hazard ratios (HR) and the corresponding 95% confidence intervals (CI) for overall survival (OS) were analyzed through random or fixed effects models. Univariate and multivariate analyses were independently performed. Subgroup analyses, heterogeneity and publication bias were investigated to further enhance reliability. RESULTS: This research indicated that elevated expression of ZEB-1 significantly predicted worse OS in patients with solid tumors. In the univariate analysis, the pooled HR for OS was 1.66 (95% CI: 1.45-1.90; P < 0.01). Meanwhile, in multivariate analysis, the pooled HR for OS was 2.28 (95% CI: 1.58-3.30; P < 0.01). Begg's funnel plot and Begg's test did not show evidence of significant publication bias, both in univariate analysis and multivariate analysis. CONCLUSIONS: High expression of ZEB-1 was associated with poorer OS, suggesting that ZEB-1 may be a potential biomarker for the prediction of prognosis, and a novel therapeutic target in human solid tumors.

Navigation in Unknown Dynamic Environments Based on Deep Reinforcement Learning.

In this paper, we propose a novel Deep Reinforcement Learning (DRL) algorithm which can navigate non-holonomic robots with continuous control in an unknown dynamic environment with moving obstacles. We call the approach MK-A3C (Memory and Knowledge-based Asynchronous Advantage Actor-Critic) for short. As its first component, MK-A3C builds a GRU-based memory neural network to enhance the robot's capability for temporal reasoning. Robots without it tend to suffer from a lack of rationality in face of incomplete and noisy estimations for complex environments. Additionally, robots with certain memory ability endowed by MK-A3C can avoid local minima traps by estimating the environmental model. Secondly, MK-A3C combines the domain knowledge-based reward function and the transfer learning-based training task architecture, which can solve the non-convergence policies problems caused by sparse reward. These improvements of MK-A3C can efficiently navigate robots in unknown dynamic environments, and satisfy kinetic constraints while handling moving objects. Simulation experiments show that compared with existing methods, MK-A3C can realize successful robotic navigation in unknown and challenging environments by outputting continuous acceleration commands.

Deep Reinforcement Learning-Based Traffic Signal Control Using High-Resolution Event-Based Data.

Reinforcement learning (RL)-based traffic signal control has been proven to have great potential in alleviating traffic congestion. The state definition, which is a key element in RL-based traffic signal control, plays a vital role. However, the data used for state definition in the literature are either coarse or difficult to measure directly using the prevailing detection systems for signal control. This paper proposes a deep reinforcement learning-based traffic signal control method which uses high-resolution event-based data, aiming to achieve cost-effective and efficient adaptive traffic signal control. High-resolution event-based data, which records the time when each vehicle-detector actuation/de-actuation event occurs, is informative and can be collected directly from vehicle-actuated detectors (e.g., inductive loops) with current technologies. Given the event-based data, deep learning techniques are employed to automatically extract useful features for traffic signal control. The proposed method is benchmarked with two commonly used traffic signal control strategies, i.e., the fixed-time control strategy and the actuated control strategy, and experimental results reveal that the proposed method significantly outperforms the commonly used control strategies.

Scaling the repetition rate of thulium-doped ultrafast soliton fiber lasers to the GHz regime.

GHz high repetition rate compact sources with femtosecond pulse durations and stable performance can enable a wide range of applications. In this paper, several high repetition rate ultrafast thulium fiber lasers with repetition rates varying between 532 MHz to 1.25 GHz are demonstrated with femtosecond pulse durations down to 426 fs. An approach of maintaining comparable pulse energies while scaling the repetition rates allows high-quality femtosecond mode-locking performance with low noise performance in thulium soliton lasers for the first time.