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242
result(s) for
"Xu, Mengwei"
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Relaxed constant positive linear dependence constraint qualification and its application to bilevel programs
2020
Relaxed constant positive linear dependence constraint qualification (RCPLD) for a system of smooth equalities and inequalities is a constraint qualification that is weaker than the usual constraint qualifications such as Mangasarian Fromovitz constraint qualification and the linear constraint qualification. Moreover RCPLD is known to induce an error bound property. In this paper we extend RCPLD to a very general feasibility system which may include Lipschitz continuous inequality constraints, complementarity constraints and abstract constraints. We show that this RCPLD for the general system is a constraint qualification for the optimality condition in terms of limiting subdifferential and limiting normal cone and it is a sufficient condition for the error bound property under the strict complementarity condition for the complementarity system and Clarke regularity conditions for the inequality constraints and the abstract constraint set. Moreover we introduce and study some sufficient conditions for RCPLD including the relaxed constant rank constraint qualification. Finally we apply our results to the bilevel program.
Journal Article
Digital non-Foster-inspired electronics for broadband impedance matching
2024
Narrow bandwidths are a general bottleneck for applications relying on passive, linear, subwavelength resonators. In the past decades, several efforts have been devoted to overcoming this challenge, broadening the bandwidth of small resonators by the means of analog non-Foster matching networks for radiators, antennas and metamaterials. However, most non-Foster approaches present challenges in terms of tunability, stability and power limitations. Here, by tuning a subwavelength acoustic transducer with digital non-Foster-inspired electronics, we demonstrate five-fold bandwidth enhancement compared to conventional analog non-Foster matching. Long-distance transmission over airborne acoustic channels, with approximately three orders of magnitude increase in power level, validates the performance of the proposed approach. We also demonstrate convenient reconfigurability of our non-Foster-inspired electronics. This implementation provides a viable solution to enhance the bandwidth of sub-wavelength resonance-based systems, extendable to the electromagnetic domain, and enables the practical implementation of airborne and underwater acoustic radiators.
Resonance-based systems such as electroacoustic transducers are often limited by narrow bandwidth. Here, authors report a digital non-Foster inspired circuit demonstrating significant bandwidth and power level enhancement with greater reconfigurability than conventional analog non-Foster approaches.
Journal Article
Relaxed Constant Positive Linear Dependence Constraint Qualification for Disjunctive Systems
2023
The disjunctive system is a system involving a disjunctive set which is the union of finitely many polyhedral convex sets. In this paper, we introduce a notion of the relaxed constant positive linear dependence constraint qualification (RCPLD) for the disjunctive system. For a disjunctive system, our notion is weaker than the one we introduced for a more general system recently (J. Glob. Optim. 2020) and is still a constraint qualification. To obtain the local error bound for the disjunctive system, we introduce the piecewise RCPLD under which the error bound property holds if all inequality constraint functions are subdifferentially regular and the rest of the constraint functions are smooth. We then specialize our results to the ortho-disjunctive program, which includes the mathematical program with equilibrium constraints (MPEC), the mathematical program with vanishing constraints (MPVC) and the mathematical program with switching constraints (MPSC) as special cases. For MPEC, we recover MPEC-RCPLD, an MPEC variant of RCPLD and propose the MPEC piecewise RCPLD to obtain the error bound property. For MPVC, we introduce new constraint qualifications MPVC-RCPLD and the piecewise RCPLD, which also implies the local error bound. For MPSC, we show that both RCPLD and the piecewise RCPLD coincide and hence it leads to the local error bound.
Journal Article
Ubiquitous memory augmentation via mobile multimodal embedding system
2025
Forgetting is inevitable in human memory. Recently, multimodal embedding models have been proposed to vectorize multimodal reality into a unified embedding space. Once generated, these embeddings allow mobile users to quickly retrieve relevant information, effectively augmenting their memory. However, as the model’s capacity increases, its resource consumption also rises. The resulting slow throughput and significant computational resource requirements hinder its deployment on mobile devices. In this paper, we present Reminisce, an efficient on-device multimodal embedding system that enables high-throughput embedding and precise retrieval on resource-constrained mobile devices. The core design draws inspiration from the memory functions of the human brain, utilizing coarse-grained embeddings to identify likely candidates, which are then refined through query-driven fine-grained retrieval. A series of algorithm-hardware orchestrated optimizations automatically navigates this process and strengthen the embedding quality. Experiments show that Reminisce provides high-quality embedding representation with high throughput while operating silently in the background with negligible memory usage and reduced energy consumption.
AI applications on mobile devices are constrained by the high resource demands of large models. Here, the authors developed an efficient on-device multimodal embedding system.
Journal Article
Research overview on the genetic mechanism underlying the biosynthesis of polysaccharide in tuber plants
2024
Tuber plants are of great significance in the world as human food crops. Polysaccharides, important metabolites in tuber plants, also serve as a source of innovative drugs with significant pharmacological effects. These drugs are particularly known for their immunomodulation and antitumor properties. To fully exploit the potential value of tuber plant polysaccharides and establish a synthetic system for their targeted synthesis, it is crucial to dissect their metabolic processes and genetic regulatory mechanisms. In this article, we provide a comprehensive summary of the basic pathways involved in the synthesis of various types of tuber plant polysaccharides. We also outline the key research progress that has been made in this area in recent years. We classify the main types and functions of tuber plant polysaccharides and analyze the biosynthetic processes and genetic regulation mechanisms of key enzymes involved in the metabolic pathways of starch, cellulose, pectin, and fructan in tuber plants. We have identified hexokinase and glycosyltransferase as the key enzymes involved in the polysaccharide synthesis process. By elucidating the synthesis pathway of polysaccharides in tuber plants and understanding the underlying mechanism of action of key enzymes in the metabolic pathway, we can provide a theoretical framework for enhancing the yield of polysaccharides and other metabolites in plant culture cells. This will ultimately lead to increased production efficiency.
Journal Article
Optimizing Adsorption of 17α-Ethinylestradiol from Water by Magnetic MXene Using Response Surface Methodology and Adsorption Kinetics, Isotherm, and Thermodynamics Studies
2021
Magnetic MXene composite Fe3O4@Ti3C2 was successfully prepared and employed as 17α-ethinylestradiol (EE2) adsorbent from water solution. The response surface methodology was employed to investigate the interactive effects of adsorption parameters (adsorption time, pH of the solution, initial concentration, and the adsorbent dose) and optimize these parameters for obtaining maximum adsorption efficiency of EE2. The significance of independent variables and their interactions were tested by the analysis of variance (ANOVA) and t-test statistics. Optimization of the process variables for maximum adsorption of EE2 by Fe3O4@Ti3C2 was performed using the quadratic model. The model predicted maximum adsorption of 97.08% under the optimum conditions of the independent variables (adsorption time 6.7 h, pH of the solution 6.4, initial EE2 concentration 0.98 mg L−1, and the adsorbent dose 88.9 mg L−1) was very close to the experimental value (95.34%). pH showed the highest level of significance with the percent contribution (63.86%) as compared to other factors. The interactive influences of pH and initial concentration on EE2 adsorption efficiency were significant (p < 0.05). The goodness of fit of the model was checked by the coefficient of determination (R2) between the experimental and predicted values of the response variable. The response surface methodology successfully reflects the impact of various factors and optimized the process variables for EE2 adsorption. The kinetic adsorption data for EE2 fitted well with a pseudo-second-order model, while the equilibrium data followed Langmuir isotherms. Thermodynamic analysis indicated that the adsorption was a spontaneous and endothermic process. Therefore, Fe3O4@Ti3C2 composite present the outstanding capacity to be employed in the remediation of EE2 contaminated wastewaters.
Journal Article
Insights on Antitumor Activity and Mechanism of Natural Benzophenanthridine Alkaloids
2023
Benzophenanthridine alkaloids are a class of isoquinoline compounds, which are widely found in the plants of papaveraceae, corydalis, and rutaceae. Biological activities and clinical studies have shown that benzophenanthridine alkaloids have inhibitory effects on many cancers. Considering that the anticancer activities and mechanisms of many natural benzophenanthridine alkaloids have been discovered in succession, the purpose of this paper is to review the anticancer effects of benzophenanthridine alkaloids and explore the application potential of these natural products in the development of antitumor drugs. A literature survey was carried out using Scopus, Pubmed, Reaxys, and Google Scholar databases. This review summarizes and analyzes the current status of research on the antitumor activity and antitumor mechanism of natural products of benzophenanthridine from different sources. The research progress of the antitumor activity of natural products of benzophenanthridine from 1983 to 2023 was reviewed. The antitumor activities of 90 natural products of benzophenanthridine and their related analogues were summarized, and the results directly or indirectly showed that natural products of benzophenanthridine had the effects of antidrug-resistant tumor cell lines, antitumor stem cells, and inducing ferroptosis. In conclusion, benzophenanthridine alkaloids have inhibitory effects on a variety of cancers and have the potential to counteract tumor resistance, and they have great application potential in the development of antitumor drugs.
Journal Article
Marine-Derived Bisindoles for Potent Selective Cancer Drug Discovery and Development
by
Liu, Yan
,
Peng, Rui
,
Zhang, Guangshuai
in
anticancer drug
,
Antineoplastic Agents - chemistry
,
antitumor activity
2024
Marine-derived bisindoles exhibit structural diversity and exert anti-cancer influence through multiple mechanisms. Comprehensive research has shown that the development success rate of drugs derived from marine natural products is four times higher than that of other natural derivatives. Currently, there are 20 marine-derived drugs used in clinical practice, with 11 of them demonstrating anti-tumor effects. This article provides a thorough review of recent advancements in anti-tumor exploration involving 167 natural marine bisindole products and their derivatives. Not only has enzastaurin entered clinical practice, but there is also a successfully marketed marine-derived bisindole compound called midostaurin that is used for the treatment of acute myeloid leukemia. In summary, investigations into the biological activity and clinical progress of marine-derived bisindoles have revealed their remarkable selectivity, minimal toxicity, and efficacy against various cancer cells. Consequently, they exhibit immense potential in the field of anti-tumor drug development, especially in the field of anti-tumor drug resistance. In the future, these compounds may serve as promising leads in the discovery and development of novel cancer therapeutics.
Journal Article
The role of sirtuin1 in liver injury: molecular mechanisms and novel therapeutic target
2024
Liver disease is a common and serious threat to human health. The progression of liver diseases is influenced by many physiologic processes, including oxidative stress, inflammation, bile acid metabolism, and autophagy. Various factors lead to the dysfunction of these processes and basing on the different pathogeny, pathology, clinical manifestation, and pathogenesis, liver diseases are grouped into different categories. Specifically, Sirtuin1 (SIRT1), a member of the sirtuin protein family, has been extensively studied in the context of liver injury in recent years and are confirmed the significant role in liver disease. SIRT1 has been found to play a critical role in regulating key processes in liver injury. Further, SIRT1 seems to cause divers outcomes in different types of liver diseases. Recent studies have showed some therapeutic strategies involving modulating SIRT1, which may bring a novel therapeutic target. To elucidate the mechanisms underlying the role of sirtuin1 in liver injury and its potentiality as a therapeutic target, this review outlines the key signaling pathways associated with sirtuin1 and liver injury, and discusses recent advances in therapeutic strategies targeting sirtuin1 in liver diseases.
Journal Article
Suspension Culture Optimization and Transcriptome-Guided Identification of Candidate Regulators for Militarine Biosynthesis in Bletilla striata
2025
Background: Bletilla striata is a medicinal orchid, whose bioactive constituent militarine has therapeutic interest but limited natural availability. Suspension culture coupled with transcriptomics offers a scalable production route and a means to uncover biosynthetic regulators. Methods: Four B. striata landraces were evaluated. Single-factor experiments and response surface methodology optimized sucrose, NH4NO3, and agitation to maximize biomass and militarine yield. Militarine and four related metabolites were quantified by HPLC-UV. For transcriptomics, RNA from high- and low-producing landraces was sequenced on Illumina HiSeq, assembled de novo, and analyzed with RSEM (FPKM) and DESeq2 to identify DEGs. Results: The landrace SMPF-NL achieved the highest militarine yield (33.06 mg/g) under optimized conditions (sucrose, 35 g/L; NH4NO3, 625 mg/L; agitation, 135 rpm; and half-strength MS medium with 1.0 mg/L of 6-BA, 3.0 mg/L of 2,4-D, and 0.5 mg/L of NAA). Transcriptomic profiling highlighted candidate biosynthetic and regulatory genes, including SuSy2, SUS, ALDO, AOC3, Comt, GOT2, MAOB, BGLU20, and BGLU22. Conclusions: We present an optimized suspension culture system and transcriptomic leads that lay the groundwork for the functional validation and scale-up of controlled militarine production.
Journal Article