Self-Supervised Learning for Time Series Analysis: Taxonomy, Progress, and Prospects.

Self-supervised learning (SSL) has recently achieved impressive performance on various time series tasks. The most prominent advantage of SSL is that it reduces the dependence on labeled data. Based on the pre-training and fine-tuning strategy, even a small amount of labeled data can achieve high performance. Compared with many published self-supervised surveys on computer vision and natural language processing, a comprehensive survey for time series SSL is still missing. To fill this gap, we review current state-of-the-art SSL methods for time series data in this article. To this end, we first comprehensively review existing surveys related to SSL and time series, and then provide a new taxonomy of existing time series SSL methods by summarizing them from three perspectives: generative-based, contrastive-based, and adversarial-based. These methods are further divided into ten subcategories with detailed reviews and discussions about their key intuitions, main frameworks, advantages and disadvantages. To facilitate the experiments and validation of time series SSL methods, we also summarize datasets commonly used in time series forecasting, classification, anomaly detection, and clustering tasks. Finally, we present the future directions of SSL for time series analysis.

Outcome expectations and working alliance may be more important for patients from rural areas during the transition to college life: An exploratory within-patient analysis.

OBJECTIVE: Research has given limited attention to the distinction between patients from rural and urban areas, especially concerning the frequent overlap between rural living and low socio-economic status (SES). To shed more light on this, we explored the differential treatment processes between patients from rural and urban areas. METHOD: Seven hundred and fourteen patients recruited from a university counseling center in China filled out the questionnaires for Outcome Expectation (OE), Session Alliance Inventory (SAI) and Clinical Outcomes in Routine Evaluation-Outcome Measure (CORE-OM) each session. Data was analyzed using the disaggregated cross-lagged panel model and the asymmetric fixed-effect model. RESULTS: The findings indicated a reciprocal within-patient relation between OE and SAI for the whole sample. SAI mediated the effect of OE on next-session CORE-OM for patients from rural areas, with a significantly greater indirect effect than for patients from the urban areas. Asymmetric effects were found for OE among patients from urban areas, for whom drops in OE predicted worse next-session CORE-OM more strongly than improvements in OE predicted improved CORE-OM. CONCLUSION: This study provided preliminary evidence for differential OE-alliance-outcome predictions between patients with different SES and affirmed a reciprocal OE-alliance relation in a Chinese sample during the transition period of college.

Purification, characterization, antioxidant and moisture-preserving activities of polysaccharides from Rosa rugosa petals.

The present study, we prepared polysaccharides from Rosa rugosa petals (RRPS) using hot-water extraction and purified the polysaccharides by chromatography to obtain RRPS-1 and RRPS-2. Preliminary structural features of RRPS were characterized by different instrumental methods, such as HPGPC, FT-IR, and GC analysis. The average molecular weights of RRPS-1 and RRPS-2 were 8.8 kDa and 443.8 kDa, respectively. Then, antioxidant and moisture-preserving activities of RRPS were determined in vitro. The analysis of antioxidant activities suggested that RRPS-2 had good potential for scavenging activity of radicals. We also found that the RRPS-2 has strong moisture-preserving activity in vitro. These results clearly indicated that RRPS-2 might have a good potential to be utilized in pharmaceutical, food and cosmetics industries.

Long-term effects of neoadjuvant radiotherapy, adjuvant radiotherapy, and chemotherapy-only on survival of locally advanced non-small cell lung Cancer undergoing surgery: a propensity-matched analysis.

BACKGROUND: The optimal timing of radiotherapy (RT) with respect to surgery remains controversial for locally advanced non-small cell lung cancer (LA NSCLC) undergoing surgery and the long-term effect of neoadjuvant RT, adjuvant RT, and chemotherapy-only on survival is unknown. METHODS: A retrospective study with Greedy 5 → 1 Digit propensity score matching technique was performed for locally advanced NSCLC patients identified from the Surveillance, Epidemiology, and End Results (SEER) database during 2004 to 2012. Kaplan-Meier and the log-rank test were conducted to compare NSCLC-specific survival. Cox proportional hazards multivariable regression was performed to assess the impact of different treatment regimens on cancer-specific mortality after adjustment for demographic factors, histology type, tumor grade, tumor size, nodal stage, and extent of resection. RESULTS: One thousand, two hundred and seventy-eight locally advanced NSCLC patients undergoing surgery were identified after propensity matching. Cox regression analyses showed the risk of cancer-specific mortality is not significantly different among neoadjuvant RT, adjuvant RT, and chemotherapy-only. Subgroup analyses showed that for patients with T1/2 & N2/3, the surgery plus chemotherapy-only group showed markedly higher mortality risk (HR = 1.42, 95%CI:1.10-1.83) than the neoadjuvant RT group. Other risk factors include older age, higher tumor grade, larger tumor size, and greater lymph node involvement. CONCLUSIONS: The findings of this study suggest that the benefit of additional neoadjuvant or adjuvant RT to chemotherapy may be linked to a proper selection of LA NSCLC patients who undergo surgery. The timing of radiotherapy should be decided on the premise of fully considering patients' condition and the quality of life after treatment.

Synthesis and affinities of C3-symmetric thioglycoside-containing trimannosides.

Thioglycoside-containing trimannose analogs were designed and prepared to mimic the natural N-glycan core trisaccharide α-d-Man-(1→3)-[α-d-Man-(1→6)]-d-Man. (1→6)-S-Linked trimannoside 1 and its trivalent cluster 2 were synthesized in 11 and 15 steps, respectively, taking advantages of the armed mannopyranosyl trichloroacetimidate as glycosyl donor. Hemagglutination inhibition of the two new thiomannotriose analogs was preliminarily examined. Comparing to the parent trimannoside α-d-Man-(1→3)-[α-d-Man-(1→6)]-d-Man-OMe, the cluster mannotrioside 2 presented a comparable binding affinity to Con A, while the monomer 6-S-trimannoside 1 exhibited a slightly lower inhibition ability.

Identification of two novel brominated contaminants in water samples by ultra-high performance liquid chromatography-Orbitrap Fusion Tribrid mass spectrometer.

Tetrabromobisphenol A mono(2-hydroxyethyl ether) (TBBPA-MHEE) and TBBPA mono(glycidyl ether) (TBBPA-MGE), two impurities of TBBPA derivatives, were hypothesized to be novel brominated contaminants with potential toxicity. However, due to lacking of analytical method and pure standards, their environmental behavior and toxicity have not been studied. Herein we developed a sensitive method based on ultra-high performance liquid chromatography-Orbitrap Fusion Tribrid mass spectrometer (UHPLC-Orbitrap Fusion TMS) for simultaneous detection of TBBPA-MHEE and TBBPA-MGE in water samples. The sample pretreatment method and the experimental conditions of UHPLC and Orbitrap Fusion TMS, were optimized in detail. The instrument detection limits (IDLs) for TBBPA-MHEE and TBBPA-MGE were 0.5pg and 0.6pg, respectively. The method detection limits (MDLs) for TBBPA-MHEE and TBBPA-MGE in river water samples were 0.9 and 0.8ng/L. With the proposed method, we were able to detect TBBPA-MHEE and TBBPA-MGE for the first time in water samples and technical products of TBBPA derivatives. Therefore, UHPLC-Orbitrap Fusion TMS is a simple and effective tool for identification and quantification of novel contaminants in the environment.

Identification of tetrabromobisphenol A allyl ether and tetrabromobisphenol A 2,3-dibromopropyl ether in the ambient environment near a manufacturing site and in mollusks at a coastal region.

Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants (BFRs) and has been frequently detected in the environment and biota. Recent studies have found that derivatives of TBBPA, such as TBBPA bis(allyl) ether (TBBPA BAE) and TBBPA bis(2,3-dibromopropyl) ether (TBBPA BDBPE) are present in various environmental compartments. In this work, using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS), TBBPA allyl ether (TBBPA AE) and TBBPA 2,3-dibromopropyl ether (TBBPA DBPE) were identified in environmental samples and further confirmed by synthesized standards. Soil, sediment, rice hull, and earthworm samples collected near a BFR manufacturing plant were found to contain these two compounds. In sediments, the concentrations of TBBPA AE and TBBPA DBPE ranged from 1.0 to 346.6 ng/g of dry weight (dw) and from 0.7 to 292.7 ng/g of dw, respectively. TBBPA AE and TBBPA DBPE in earthworm and rice hull samples were similar to soil samples, which ranged from below the method limit of detection (LOD, <0.002 ng/g of dw) to 0.064 ng/g of dw and from below the LOD (<0.008 ng/g of dw) to 0.58 ng/g of dw, respectively. Furthermore, mollusks collected from the Chinese Bohai Sea were used as a bioindicator to investigate the occurrence and distribution of these compounds in the coastal environment. The detection frequencies of TBBPA AE and TBBPA DBPE were 41 and 32%, respectively, and the concentrations ranged from below LOD (<0.003 ng/g of dw) to 0.54 ng/g of dw, with an average of 0.09 ng/g of dw, for TBBPA AE, and from below LOD (<0.008 ng/g of dw) to 1.41 ng/g of dw, with an average of 0.15 ng/g of dw, for TBBPA DBPE.

Total synthesis of (-)-orthodiffenes A and C.

The efficient and concise synthesis of (-)-orthodiffenes A and C has been accomplished for the first time in eight steps from readily available chiral synthons, D-mannose and D-ethyl lactate. Our work confirmed the complete structure of orthodiffenes A and C, including their absolute stereochemistry. The key steps of our total synthesis involved cis-fused tetrahydrofuran cyclization, one-pot deprotection-lactonization, and intramolecular benzoyl migration according to a biosynthetic hypothesis of orthodiffenes.

Characteristics of osseous septum of split cord malformation in patients presenting with scoliosis: a retrospective study of 48 cases.

BACKGROUND/AIMS: The coexistence of scoliosis and split cord malformation (SCM) is often encountered. The characteristics of the osseous septum of SCM are still unknown to us. Here we try to delineate the configuration and nature of the osseous septa. The correlation between scoliosis and SCM is also discussed. METHODS: 48 patients hospitalized for scoliosis were studied. SCM was subsequently identified in all of the patients. These patients underwent operations and were retrospectively evaluated. RESULTS: The figuration, component, location and nature of osseous septa are described. 47 of the 48 SCMs (98%) were type I. Only 1 case was type II. 43 patients (90%) had 1 osseous septum. The other 5 patients (10%) had 2 osseous septa at different levels. 41 septa (78%) were mainly made of cortical bone, another 6 septa (11%) were mainly made of cancellous bone, while the other 6 (11%) were bone together with soft tissues. The prominent central blood vessels were found in 19 cases (36%). 10 osseous septa (19%) were derived from neural arches. 15 osseous septa (28%) were from both vertebral bodies and neural arches. CONCLUSION: We assumed that SCM might contribute to the progress of scoliosis. It is recommended that removal of the spur be carried out before corrective surgery on the spine.