Quadratic Matrix Factorization With Applications to Manifold Learning.

Matrix factorization is a popular framework for modeling low-rank data matrices. Motivated by manifold learning problems, this paper proposes a quadratic matrix factorization (QMF) framework to learn the curved manifold on which the dataset lies. Unlike local linear methods such as the local principal component analysis, QMF can better exploit the curved structure of the underlying manifold. Algorithmically, we propose an alternating minimization algorithm to optimize QMF and establish its theoretical convergence properties. Moreover, to avoid possible over-fitting, we then propose a regularized QMF algorithm and discuss how to tune its regularization parameter. Finally, we elaborate how to apply the regularized QMF to manifold learning problems. Experiments on a synthetic manifold learning dataset and three real datasets, including the MNIST handwritten dataset, a cryogenic electron microscopy dataset, and the Frey Face dataset, demonstrate the superiority of the proposed method over its competitors.

Model-free tracking control of complex dynamical trajectories with machine learning.

Nonlinear tracking control enabling a dynamical system to track a desired trajectory is fundamental to robotics, serving a wide range of civil and defense applications. In control engineering, designing tracking control requires complete knowledge of the system model and equations. We develop a model-free, machine-learning framework to control a two-arm robotic manipulator using only partially observed states, where the controller is realized by reservoir computing. Stochastic input is exploited for training, which consists of the observed partial state vector as the first and its immediate future as the second component so that the neural machine regards the latter as the future state of the former. In the testing (deployment) phase, the immediate-future component is replaced by the desired observational vector from the reference trajectory. We demonstrate the effectiveness of the control framework using a variety of periodic and chaotic signals, and establish its robustness against measurement noise, disturbances, and uncertainties.

Structural position vectors and symmetries in complex networks.

Symmetries, due to their fundamental importance to dynamical processes on networks, have attracted a great deal of current research. Finding all symmetric nodes in large complex networks typically relies on automorphism groups from algebraic-group theory, which are solvable in quasipolynomial time. We articulate a conceptually appealing and computationally extremely efficient approach to finding and characterizing all symmetric nodes by introducing a structural position vector (SPV) for each node in networks. We establish the mathematical result that symmetric nodes must have the same SPV value and demonstrate, using six representative complex networks from the real world, that all symmetric nodes in these networks can be found in linear time. Furthermore, the SPVs not only characterize the similarity of nodes but also quantify the nodal influences in propagation dynamics. A caveat is that the proved mathematical result relating the SPV values to nodal symmetries is not sufficient; i.e., nodes having the same SPV values may not be symmetric, which arises in regular networks or networks with a dominant regular component. We point out with an analysis that this caveat is, in fact, shared by the known existing approaches to finding symmetric nodes in the literature. We further argue, with the aid of a mathematical analysis, that our SPV method is generally effective for finding the symmetric nodes in real-world networks that typically do not have a dominant regular component. Our SPV-based framework, therefore, provides a physically intuitive and computationally efficient way to uncover, understand, and exploit symmetric structures in complex networks arising from real-world applications.

Discovery of novel PRMT5 inhibitors bearing a methylpiperazinyl moiety.

Background: PRMT5 is an epigenetics-related enzyme, which plays a critical role in cancer development. Hence PRMT5 inhibition has been validated as a promising therapeutic strategy. Methods & Results: We synthesized a series of methylpiperazinyl derivatives as novel PRMT5 inhibitors that were achieved by scaffold-hopping from EPZ015666 by virtual screening followed by rational drug design. Among all compounds 43g, bearing a thiourea linker, showed antitumor activity across multiple cancer cell lines and reduced the level of symmetric arginine dimethylation of SmD3 dose-dependently. Moreover, 43g selectively inhibited PRMT5 among protein arginine methyltransferase isoforms. Further proteomics analysis revealed that 43g remarkably reduced the global arginine dimethylation level in a cellular context. Conclusion: This work provides new chemical templates for future structural optimization of PRMT5-related cancer treatments.

Metamorphoses and explosively remote synchronization in dynamical networks.

We uncover a phenomenon in coupled nonlinear networks with a symmetry: as a bifurcation parameter changes through a critical value, synchronization among a subset of nodes can deteriorate abruptly, and, simultaneously, perfect synchronization emerges suddenly among a different subset of nodes that are not directly connected. This is a synchronization metamorphosis leading to an explosive transition to remote synchronization. The finding demonstrates that an explosive onset of synchrony and remote synchronization, two phenomena that have been studied separately, can arise in the same system due to symmetry, providing another proof that the interplay between nonlinear dynamics and symmetry can lead to a surprising phenomenon in physical systems.

A New Looped Functional to Synchronize Neural Networks With Sampled-Data Control.

This article deals with the problem of sampled-data-based synchronization of neural networks with and without considering time delay. A novel looped functional is introduced in the construction of Lyapunov functional, which adequately utilizes the state information of e(tk) , e(t) , e(tk+1) , e(tk-τc) , e(t-τc) , and e(tk+1-τc) . Then, by using this functional and employing a generalized free-matrix-based integral inequality (GFMBII), several sufficient conditions are derived to ensure that the slave system is synchronous with the master system. Also, the sampled-data controller can be obtained by using the linear matrix inequality (LMI) technique. Finally, two numerical examples are illustrated to show the validity and advantages of the proposed method.

[Research progress of full endoscopic transforaminal lumbar interbody fusion].

Full endoscopic transforaminal lumbar interbody fusion has been used widely in the field of minimally invasive spine surgery in recent years. This paper briefly introduces the development history, technical points, indications, curative effects and complications. Authors believe that the full endoscopic transforaminal lumbar interbody fusion has the same clinical effects as traditional surgery, and can effectively reduce tissue damage and intraoperative bleeding, reduce the incidence of postoperative low back pain, shorten the time to get out of bed, and reduce the average hospitalization time. However, it is still necessary to improve the long-term follow up in order to further evaluate the effectiveness and safety of the procedure.

Radiofrequency Catheter Ablation of Supraventricular Tachycardia in Patients With Pulmonary Hypertension: Feasibility and Long-Term Outcome.

BACKGROUND: Supraventricular tachycardia (SVT) occurs commonly and is strongly correlated with clinical deterioration in patients with pulmonary hypertension (PH). This study aimed to investigate the feasibility and long-term outcome of radiofrequency catheter ablation (RFCA) in PH patients with SVT. MATERIALS AND METHODS: Consecutive PH patients with SVT who were scheduled to undergo electrophysiological study and RFCA between September 2010 and July 2019 were included. The acute results and long-term success of RFCA were assessed after the procedure. RESULTS: In total, 71 PH patients with 76 episodes of SVT were analyzed. Cavotricuspid isthmus-dependent atrial flutter (n = 33, 43.5%) was the most common SVT type, followed by atrioventricular nodal reentrant tachycardia (n = 16, 21.1%). Of the 71 patients, 60 (84.5%) underwent successful electrophysiological study and were subsequently treated by RFCA. Among them, acute sinus rhythm was restored in 54 (90.0%) patients, and procedure-related complications were observed in 4 (6.7%) patients. Univariate logistic regression analysis showed that cavotricuspid isthmus-independent atrial flutter [odds ratio (OR) 25.00, 95% confidence interval (CI) 3.45-180.98, p = 0.001] and wider pulmonary artery diameter (OR 1.19, 95% CI 1.03-1.38; p = 0.016) were associated with RFCA failure. During a median follow-up of 36 (range, 3-108) months, 7 patients with atrial flutter experienced recurrence, yielding a 78.3% 3-year success rate for RFCA treatment. CONCLUSION: The findings suggest that RFCA of SVT in PH patients is feasible and has a good long-term success rate. Cavotricuspid isthmus-independent atrial flutter and a wider PAD could increase the risk for ablation failure.

Erythrocyte-mimicking paclitaxel nanoparticles for improving biodistributions of hydrophobic drugs to enhance antitumor efficacy.

Recent decades have witnessed several nanocrystal-based hydrophobic drug formulations because of their excellent performance in improving drug loading and controlling drug release as mediate drug forms in tablets or capsules. However, the intravenous administration of drug nanocrystals was usually hampered by their hydrophobic surface properties, causing short half-life time in circulation and low drug distribution in tumor. Here, we proposed to enclose nanocrystals (NC) of hydrophobic drug, such as paclitaxel (PTX) into erythrocyte membrane (EM). By a series of formulation optimizations, spherical PTX nanoparticles (PN) with the particle size of around 280 nm were successfully cloaked in erythrocyte membrane, resulting in a PTX-NP-EM (PNM) system. The PNM could achieve high drug loading of PTX (>60%) and stabilize the particle size significantly compared to PN alone. Besides, the fluorescence-labeling PNM presented better tumor cell uptake, stronger cytotoxicity, and higher drug accumulation in tumor compared to PN. Finally, the PNM was found to be the most effective against tumor growth among all PTX formulations in tumor-bearing mice models, with much lower system toxicity than control formulation. In general, the PNM system with high drug-loading as well as superior bio-distributions in vivo could be served as a promising formulation.

π-Expanded Coumarins: One-Pot Photo Synthesis of 5H-Benzo[12,1]tetrapheno[7,6,5-cde]chromen-5-ones and Photophysical Properties.

The synthesis of a unique type of π-expanded coumarin derivatives, bearing six fused phenyl rings, was achieved via one-pot Suzuki reaction and visible light-driven electrocyclization. The large π-expanded 5H-benzo[12,1]tetrapheno[7,6,5-cde]chromen-5-ones were obtained in good to high yields from 1-bromo-2H-phenaleno[1,2,3-de]chromen-2-ones, and the intriguing optical properties were explored by altering the attached functional groups. 2-Arylaminosubstituted-5H-benzo[12,1]tetrapheno[7,6,5-cde]chromen-5-ones showed a large Stokes shift (4005 cm-1) or excellent fluorescence quantum yield (Φf = 0.75) along with significant bathochromic shift in tetrahydrofuran.

Design, synthesis and biological evaluation of novel dithiocarbamate-substituted diphenylaminopyrimidine derivatives as BTK inhibitors.

Bruton's tyrosine kinase (BTK) has emerged as an attractive target related to B-lymphocytes dysfunctions, especially hematologic malignancies and autoimmune diseases. In our study, a series of diphenylaminopyrimidine derivatives bearing dithiocarbamate moieties were designed and synthesized as novel BTK inhibitors for treatment of B-cell lymphoma. Among all these compounds, 30ab (IC50 = 1.15 ±â€¯0.19 nM) displays similar or more potent inhibitory activity against BTK than spebrutinib (IC50 = 2.12 ±â€¯0.32 nM) and FDA approved drug ibrutinib (IC50 = 3.89 ±â€¯0.57 nM), which is attributed to close binding of 30ab with BTK predicted by molecular docking. In particular, 30ab exhibits enhanced anti-proliferative activity against B-lymphoma cell lines at the IC50 concentration of 0.357 ±â€¯0.02 µM (Ramos) and 0.706 ±â€¯0.05 µM (Raji), respectively, almost 10-fold better than ibrutinib and spebrutinib. In addition, 30ab displays stronger selectivity on B-cell lymphoma over other cancer cell lines than spebrutinib. Furthermore, 30ab efficiently blocks BTK downstream pathways and results in apoptosis of cancer cells. In vivo xenograft model evaluation demonstrates the significant efficacy and broad safety margin of 30ab in treatment of B-cell lymphoma. We propose that compound 30ab is a candidate for further study and development based on our current findings.

Glutathione-Priming Nanoreactors Enable Fluorophore Core/Shell Transition for Precision Cancer Imaging.

In an attempt to develop an imaging probe with ultra-high sensitivity for a broad range of tumors in vivo and inspired by the concept of chemical synthetic nanoreactors, we designed a type of glutathione-priming fluorescent nanoreactor (GPN) with an albumin-coating shell and hydrophobic polymer core containing disulfide bonds, protonatable blocks, and indocyanine green (ICG), a near-infrared fluorophore. The albumin played multiple roles including biocompatible carriers, hydrophilic stabilizer, "receptor" of the fluorophores, and even targeting molecules. The protonation of the hydrophobic core triggered the outside-to-core transport of acidic glutathione (GSH), as well as the core-to-shell transference of ICGs after the disulfide bond cleavage by GSH, which induced strong binding of fluorophores with albumins on the GPN shell, initiating intensive fluorescence signals. As a result, the GPNs demonstrated extremely high response sensitivity and imaging contrast, proper time window, and broad cancer specificity. In fact, an orthogonal activation pattern was found in vitro with an ON/OFF ratio up to 24.7-fold. Furthermore, the nanoprobes specifically amplified the tumor signals in five cancer-bearing mouse models and actualized tumor margin delineation with a contrast up to 20-fold, demonstrating much better imaging efficacy than the other four commercially available probes. Therefore, the GPNs provide a new paradigm in developing high-performance bioresponsive nanoprobes.

Pyogenic Liver Abscess of Biliary Origin: The Existing Problems and Their Strategies.

Pyogenic liver abscess (PLA) of biliary origin in Southeast Asia mainly occurs in patients with intrahepatic bile duct stone (IBDS) and extrahepatic bile duct stone (EBDS), bilioenteric anastomosis, or biliary stent. IBDS, as an endemic to Southeast Asia, remains a frequent etiology of acute cholangitis and PLA. PLA related to IBDS is characterized by high incidences of PLA recurrence and death related to infection, and difficulties in diagnosis of concomitant cholangicarcinoma. PLA of biliary origin is more likely caused by Escherichia coli, more often presented as polymicrobial infections, and more associated with extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae isolates. In this review, the authors summarize the differences on the presumed causes, pathogens, multidrug resistance, treatment, and prognosis of PLA between biliary origin and cryptogenic origin, the latter serving as a first and foremost presumed etiology of PLA. The authors also discuss the existing problems on early diagnosis of concomitant cholangicarcinoma related to IBDS.

Transrectal microwave thermotherapy causing a short-time influence on sperm quality in Chinese chronic nonbacterial prostatitis patients.

Chronic prostatitis can affect the sperm's quality. Previous studies have shown that transrectal microwave thermotherapy (TRMT) results in symptomatic relief in patients with chronic prostatitis, but the effects on sperm have not been carefully investigated. This study evaluates the impact of TRMT on the relief or decrease of symptoms and quality of sperm when used to treat patients with chronic nonbacterial prostatitis. Sixty patients were enrolled in the study. TRMT treatment was administered over 5 days, 1 h per day. Semen examination was carried out pretreatment and immediately at the conclusion of the 5-day treatment. Also, it was repeated 1 month, 3 months, and 6 months later. The treatment's symptom relief efficacy was evaluated using the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI). After the treatment, the overall NIH-CPSI scores were lower compared to those of pretreatment. In addition, the white blood cells and lecithin in expressed prostatic secretion were normal after the treatment. The sperm count was decreased by 23.8% 3 months after the treatment, sperm motility was reduced by 10.3% immediately after treatment, and sperm deformity was increased by 17.2%. The sperm volume and PH were not affected. However, the sperm quality recovered after treatment and the malformation rate was also lower at 6 months after treatment. TRMT is a favorable and safe treatment option for patients with nonbacterial chronic prostatitis. It could relieve the patient's symptoms and impact on sperm quality in the short-term.

Hepatic schwannoma: A case report and an updated 40-year review of the literature yielding 30 cases.

Hepatic schwannoma is a rare benign disease with a good prognosis. Early diagnosis is difficult due to the absence of specific clinical presentations and its rarity. The present study briefly described a 64-year-old female patient with hepatic schwannoma mimicking intrahepatic cholangiocarcinoma. Furthermore, the clinical data of 30 patients with hepatic schwannoma were also reviewed and analyzed. The mean age of the 30 patients was 51.7 years (range, 21-83 years) and ~2/3 were female. All patients in the benign group underwent surgical treatment and survived until the last follow-up, of whom 19 received complete resection and the remaining 1 underwent liver transplantation. However, in the malignant group, only three cases who underwent the surgical resection remained alive at last follow-up. Another seven cases were succumbed to mortality, 4 cases of whom had deteriorated to have no operation opportunity by the time they saw a doctor, and among the remaining three cases with hepatectomy, 1 died of liver dysfunction at 21 days postoperatively, 2 succumbed to recurrences at 18 and 23 months postoperatively. In conclusion, hepatic schwannoma is a rare benign disease with a good prognosis. However, once the malignant transformation occurs, the prognosis is not satisfied. Complete resection is the mainstay for cure and liver transplantation is often necessary.

Carcinosarcoma of the Lesser Omentum: A Unique Case Report and Literature Review.

Carcinosarcoma is a rare tumor consisting of epithelial and mesenchymal components, both of which are histologically malignant. It usually runs an aggressive clinical course, with higher metastatic potential than other kinds of carcinomas or sarcomas.Here, we present an extremely uncommon case of carcinosarcoma occurred in the lesser omental bursa in a 65-year-old Chinese man. Metastasis was observed 2 months after operation and disappeared completely after chemotherapy. Until now, 3 years after surgery, the patient is still alive without any signs or symptoms of recurrence.To our knowledge, this is the first case of carcinosarcoma originated from lesser omentum. Surgical resection and the ifosfamide-based combination chemotherapy may be effective to carcinosarcoma in the lesser omentum.

Porta hepatic schwannoma: case report and a 30-year review of the literature yielding 15 cases.

BACKGROUND: Schwannomas located in the periportal region are extremely rare. Only 14 cases have been reported in the medical literature worldwide. Cases of porta hepatic schwannomas reported in the literature worldwide were reviewed. As a result, it is very challenging for surgeons to make a preoperative diagnosis due to its rarity and nonspecific imaging manifestations. CASE PRESENTATION: A 57-year-old Chinese female was admitted to our institution with complaint of upper abdominal distension and the abdominal CT in the local hospital revealed a hypodense mass in the porta hepatis. A fine needle aspiration (FNA) was made to confirm the diagnosis, but the result was just suggestive of spindle cell neoplasia. Eventually, the patient underwent surgery and postoperative pathology confirmed schwannoma in porta hepatis. The patient recovered uneventfully with no evidence of recurrence after a follow-up period of 41 months. CONCLUSIONS: It is essential for the final diagnosis of porta hepatic schwannomas to combine histological examination with immunohistochemistry after surgery. The main treatment of porta hepatic schwannomas is complete excision with free margins and no lymph node dissection. In some cases, biliary reconstruction or the proper hepatic and the gastroduodenal artery resection was performed because the tumor was inseparably attached to the extrahepatic bile duct or the proper hepatic and the gastroduodenal artery. Malignant transformation of schwannomas is very rare and the overall prognosis is satisfactory.

[The Effect of Hydrogen Bonding on the Spectrum of HPAM in Various Systems].

IR and UV-Vis was employed to analyzed the spectrum effect of hydrogen bonding on the partially hydrolyzed polyacrylamide polymer(HPAM). The study reveals that, the characteristic absorption peak of free amino group moves to the low frequency due to the formation of intramolecular hydrogen bonding between amide group and carboxyl group. In the water solution, intramolecular hydrogen bonding is the main factor that shifted maximal absorption towards long wavelength. Intramolecular hydrogen bonding and intermolecular hydrogen bonds exist at the same time in the water solution contains intermediate sodium and calcium ions. While in the high concentration solution, the main form between amide group and carboxyl group is intermolecular hydrogen bonding. The effect of hydrogen bonding on the spectrum of HPAM demonstrates different extent in various systems. In the water solution, the maximum absorption wavelength red shifts 8 nm. In the system contains sodium ions, this shift is 4 nm. And this shift is only 2 nm in the solution contains both sodium ions and calcium ions.

Band-gap energy as a descriptor of catalytic activity for propene oxidation over mixed metal oxide catalysts.

The development of a descriptor or descriptors that can relate the activity of catalysts to their physical properties is a major objective of catalysis research. In this study, we have found that the apparent activation energy for propene oxidation to acrolein over scheelite-structured, multicomponent, mixed metal oxides (Bi3FeMo2O12, Bi2Mo2.5W0.5O12, and Bi1-x/3V1-xMoxO4, where 0 ≤ x ≤ 1) correlates with the band gap of the catalyst measured at reaction temperature. We show through theoretical analysis of the energy components comprising the activation energy why the band-gap energy is the primary component dependent on catalyst composition and, hence, why one should expect the activation energy for propene oxidation to correlate with the band-gap energy. We also demonstrate that the change in band-gap energy with composition arises from the interplay between the sizes and energies of the V 3d, Fe 3d, Mo 4d, and W 5d orbitals, which give rise to the lowest unoccupied crystal orbitals. Both the utility of the band-gap energy as a descriptor for catalytic activity and the role of orbital overlap in determining the band gap are likely to be general features in mixed metal oxide oxidation catalysts, enabling the rational design of catalysts with greater activity for oxidation reactions.