Wind Aggregation Enhanced Triboelectric-Electromagnetic Hybrid Generator with Slit Effect.

It is of great significance to establish a low-cost, high-efficiency, self-powered micrometeorological monitoring system for agriculture, animal husbandry, and transportation. However, each additional detection element in the meteorological monitoring system increases the power consumption of the whole system by about 0.7 W. As a renewable energy technology, a triboelectric nanogenerator has the advantages of low price and self-powered sensing. To reduce the power consumption of the micrometeorological monitoring system, this work introduces an innovative solution: the wind-gathering enhanced triboelectric-electromagnetic hybrid generator (WGE-TEHG). Coupling the thin-film vibrating triboelectric nanogenerator (TENG) and electromagnetic generator (EMG), the TENG is used to monitor wind direction and the EMG is used to monitor wind speed and provide energy needed by the system. In particular, the TENG can be used as a self-powered sensor to reduce the power consumption of the sensing system. Besides, the TENG is used to produce slit effect to enhance the output performance of EMG. The experimental results show that the WGE-TEHG can build a self-powered natural environment micrometeorological sensing system. It can monitor the wind direction, wind speed, temperature, and relative humidity. This research has great application value for the self-powered sensing implementation of a hybrid TENG and EMG.

Self-Powered Agricultural Product Preservation and Wireless Monitoring Based on Dual-Functional Triboelectric Nanogenerator.

The global annual vegetable and fruit waste accounts for more than one-fifth of food waste, mainly due to deterioration. In addition, agricultural product spoilage can produce foodborne illnesses and threaten public health. Eco-friendly preservation technologies for extending the shelf life of agricultural products are of great significance to socio-economic development. Here, we report a dual-functional TENG (DF-TENG) that can simultaneously prolong the storage period of vegetables and realize wireless storage condition monitoring by harvesting the rotational energy. Under the illumination of the self-powered high-voltage electric field, the deterioration of vegetables can be effectively slowed down. It can not only decrease the respiration rate and weight loss of pakchoi but also increase the chlorophyll levels (∼33.1%) and superoxide dismutase activity (∼11.1%) after preservation for 4 days. Meanwhile, by harvesting the rotational energy, the DF-TENG can be used to drive wireless sensors for monitoring the storage conditions and location information of vegetables during transportation in real time. This work provides a new direction for self-powered systems in cost-effective and eco-friendly agricultural product preservation, which may have far-reaching significance to the construction of a sustainable society for reducing food waste.

PLD2 deletion ameliorates sepsis-induced cardiomyopathy by suppressing cardiomyocyte pyroptosis via the NLRP3/caspase 1/GSDMD pathway.

OBJECTIVE: Sepsis-induced cardiomyopathy (SICM) is a life-threatening complication. Phospholipase D2 (PLD2) is crucial in mediating inflammatory reactions and is associated with the prognosis of patients with sepsis. Whether PLD2 is involved in the pathophysiology of SICM remains unknown. This study aimed to investigate the effect of PLD2 knockout on SICM and to explore potential mechanisms. METHODS: The SICM model was established using cecal ligation and puncture in wild-type and PLD2-knockout mice and lipopolysaccharide (LPS)-induced H9C2 cardiomyocytes. Transfection with PLD2-shRNA lentivirus and a PLD2 overexpression plasmid were used to interfere with PLD2 expression in H9C2 cells. Cardiac pathological alterations, cardiac function, markers of myocardial injury, and inflammatory factors were used to evaluate the SICM model. The expression of pyroptosis-related proteins (NLRP3, cleaved caspase 1, and GSDMD-N) was assessed using western blotting, immunofluorescence, and immunohistochemistry. RESULTS: SICM mice had myocardial tissue damage, increased inflammatory response, and impaired heart function, accompanied by elevated PLD2 expression. PLD2 deletion improved cardiac histological changes, mitigated cTNI production, and enhanced the survival of the SICM mice. Compared with controls, PLD2-knockdown H9C2 exhibits a decrease in inflammatory markers and lactate dehydrogenase production, and scanning electron microscopy results suggest that pyroptosis may be involved. The overexpression of PLD2 increased the expression of NLRP3 in cardiomyocytes. In addition, PLD2 deletion decreased the expression of pyroptosis-related proteins in SICM mice and LPS-induced H9C2 cells. CONCLUSION: PLD2 deletion is involved in SICM pathogenesis and is associated with the inhibition of the myocardial inflammatory response and pyroptosis through the NLRP3/caspase 1/GSDMD pathway.

Flexible Tactile Sensors for 3D Force Detection.

As tactile force sensing has become increasingly significant in the field of machine haptics, achieving multidimensional force sensing remains a challenge. We propose a 3D flexible force sensor that consists of an axisymmetric hemispherical protrusion and four equally sized quarter-circle electrodes. By simulating the device using a force and electrical field model, it has been found that the magnitude and direction of the force can be expressed through the voltage relationship of the four electrodes when the magnitude of the shear force remains constant and its direction varies within 0-360°. The experimental results show that a resolution of 15° can be achieved in the range 0-90°. Additionally, we installed the sensor on a robotic hand, enabling it to perceive the magnitude and direction of touch and grasp actions. Based on this, the designed 3D flexible tactile force sensor provides valuable insights for multidimensional force detection and applications.

A combined pre- and intra-operative nomogram in evaluation of degrees of liver cirrhosis predicts post-hepatectomy liver failure: a multicenter prospective study.

Background: Adequate evaluation of degrees of liver cirrhosis is essential in surgical treatment of hepatocellular carcinoma (HCC) patients. The impact of the degrees of cirrhosis on prediction of post-hepatectomy liver failure (PHLF) remains poorly defined. This study aimed to construct and validate a combined pre- and intra-operative nomogram based on the degrees of cirrhosis in predicting PHLF in HCC patients using prospective multi-center's data. Methods: Consecutive HCC patients who underwent hepatectomy between May 18, 2019 and Dec 19, 2020 were enrolled at five tertiary hospitals. Preoperative cirrhotic severity scoring (CSS) and intra-operative direct liver stiffness measurement (DSM) were performed to correlate with the Laennec histopathological grading system. The performances of the pre-operative nomogram and combined pre- and intra-operative nomogram in predicting PHLF were compared with conventional predictive models of PHLF. Results: For 327 patients in this study, histopathological studies showed the rates of HCC patients with no, mild, moderate, and severe cirrhosis were 41.9%, 29.1%, 22.9%, and 6.1%, respectively. Either CSS or DSM was closely correlated with histopathological stages of cirrhosis. Thirty-three (10.1%) patients developed PHLF. The 30- and 90-day mortality rates were 0.9%. Multivariate regression analysis showed four pre-operative variables [HBV-DNA level, ICG-R15, prothrombin time (PT), and CSS], and one intra-operative variable (DSM) to be independent risk factors of PHLF. The pre-operative nomogram was constructed based on these four pre-operative variables together with total bilirubin. The combined pre- and intra-operative nomogram was constructed by adding the intra-operative DSM. The pre-operative nomogram was better than the conventional models in predicting PHLF. The prediction was further improved with the combined pre- and intra-operative nomogram. Conclusions: The combined pre- and intra-operative nomogram further improved prediction of PHLF when compared with the pre-operative nomogram. Trial Registration: Clinicaltrials.gov Identifier: NCT04076631.

Enantioselective synthesis of spirooxindole-pyran derivatives via a remote inverse-electron-demand Diels-Alder reaction of ß,γ-unsaturated amides.

Novel construction methods for obtaining 3,4'-pyran spirooxindole heterocyclic skeletons have always been the focus of attention. Herein, we report a highly enantioselective inverse-electron-demand oxa-Diels-Alder cycloaddition reaction of a ß,γ-unsaturated pyrazole amide and a N-diphenyl isatin-derived oxodiene using a bifunctional catalyst. In addition, large-scale experiments confirmed the reliability of the reaction. The resultant products of this study can be further transformed.

Contact-electro-catalysis (CEC).

Contact-electro-catalysis (CEC) is an emerging field that utilizes electron transfer occurring at the liquid-solid and even liquid-liquid interfaces because of the contact-electrification effect to stimulate redox reactions. The energy source of CEC is external mechanical stimuli, and solids to be used are generally organic as well as in-organic materials even though they are chemically inert. CEC has rapidly garnered extensive attention and demonstrated its potential for both mechanistic research and practical applications of mechanocatalysis. This review aims to elucidate the fundamental principle, prominent features, and applications of CEC by compiling and analyzing the recent developments. In detail, the theoretical foundation for CEC, the methods for improving CEC, and the unique advantages of CEC have been discussed. Furthermore, we outline a roadmap for future research and development of CEC. We hope that this review will stimulate extensive studies in the chemistry community for investigating the CEC, a catalytic process in nature.

Anti-inflammatory and protective effects of Pimpinella candolleana on ulcerative colitis in rats: a comprehensive study of quality, chemical composition, and molecular mechanisms.

Introduction: P. candolleana Wight et Arn. Is a traditional Chinese herbal medicine used by the Gelao nationality in southwest China, has been historically applied to treat various gastrointestinal disorders. Despite its traditional usage, scientific evidence elucidating its efficacy and mechanisms in treating ulcerative colitis (UC) remains sparse. This study aimed to determine the quality and chemical composition of Pimpinella candolleana and to identify its potential therapeutic targets and mechanisms in acetic acid-induced ulcerative colitis (UC) rats through integrated approaches. Methods: Morphological and microscopic characteristics, thin layer chromatography (TLC) identification, and quantitative analysis of P. candolleana were performed. UPLC-Q-TOF-MS, network pharmacology, and molecular docking were used to identify its chemical composition and predict its related targets in UC. Furthermore, a rat model was established to evaluate the therapeutic effect and potential mechanism of P. candolleana on UC. Results: Microscopic identification revealed irregular and radial arrangement of the xylem in P. candolleana, with a light green cross-section and large medullary cells. UPLC-Q-TOF-MS analysis detected and analyzed 570 metabolites, including flavonoids, coumarins, and terpenoids. Network pharmacology identified 12 effective components and 176 target genes, with 96 common targets for P. candolleana-UC, including quercetin, luteolin, and nobiletin as key anti-inflammatory components. GO and KEGG revealed the potential involvement of their targets in RELA, JUN, TNF, IKBKB, PTGS2, and CHUK, with action pathways such as PI3K-Akt, TNF, IL-17, and apoptosis. Molecular docking demonstrated strong affinity and binding between these key components (quercetin, luteolin, and nobiletin) and the key targets of the pathway, including JUN and TNF. Treatment with P. candolleana improved body weight loss, the disease activity index, and colonic histological damage in UC rats. Pimpinella candolleana also modulated the levels of IL-2 and IL-6 in UC rats, reduced the expression of pro-inflammatory cytokines such as IL-6, MAPK8, TNF-α, CHUK, and IKBKB mRNA, and decreased the expression of TNF, IKBKB, JUN, and CHUK proteins in the colon of UC rats, thereby reducing inflammation and alleviating UC symptoms. Conclusion: P. candolleana exerts its protective effect on UC by reducing the expression of proinflammatory cytokines and inhibiting inflammation, providing scientific evidence for its traditional use in treating gastrointestinal diseases. This study highlights the potential of P. candolleana as a natural therapeutic agent for UC and contributes to the development of novel medicines for UC treatment.

Boosting Efficiency in Piezo-Photocatalysis Process Using Poled Ba0.7Sr0.3TiO3 Nanorod Arrays for Pollutant Degradation and Hydrogen Production.

Recently, the combination of the piezoelectric effect in the photocatalytic process, referred to as piezo-photocatalysis, has gained considerable attention as a promising approach for enhancing the degradation of organic pollutants. In this investigation, we studied the piezo-photocatalysis by fabricating arrays of barium strontium titanate (Ba0.7Sr0.3TiO3) nanorods (BST NRs) on a glass substrate as recoverable catalysts. We found that the degradation rate constant k of the rhodamine B solution achieved 0.0447 min-1 using poled BST NRs in the piezo-photocatalytic process, indicating a 2-fold increase in efficiency compared to the photocatalytic process (0.00183 min-1) utilizing the same material. This is mainly ascribed to the generation of the piezopotential in the poled BST NRs under ultrasonic vibration. Moreover, the BST NR array demonstrated a hydrogen (H2) production rate of 411.5 µmol g-1 h-1. In the photoelectrochemical process, the photocurrent density of poled BST NRs achieved 1.97 mA cm-2 at an applied potential of 1.23 V (ERHE (reversible hydrogen electrode)) under ultrasonic vibrations, representing a 1.7-fold increase compared with the poled BST NRs without ultrasonic vibrations. The measurement results from the liquid chromatograph mass spectrometer (LC-MS) demonstrated the formulation of a degradation pathway for rhodamine B molecules. Moreover, ab initio molecular dynamics (AIMD) simulation results demonstrate the dominance of hydroxyl radicals (•OH) rather than superoxide radicals (•O2-) in the degradation process. This study not only benefits the understanding of the principle of the piezo-photocatalytic process but also provides a new perspective for improving the catalytic efficiency for organic pollutants degradation.

Subdural effusion associated with COVID-19 encephalopathy: A case report.

BACKGROUND: The precise mechanism by which severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) impacts the central nervous system remains unclear, with manifestations spanning from mild symptoms (e.g., olfactory and gustatory deficits, hallucinations, and headache) to severe complications (e.g., stroke, seizures, encephalitis, and neurally demyelinating lesions). The occurrence of single-pass subdural effusion, as described below, is extremely rare. CASE SUMMARY: A 56-year-old male patient presented with left-sided limb weakness and slurred speech as predominant clinical symptoms. Through comprehensive imaging and diagnostic assessments, he was diagnosed with cerebral infarction complicated by hemorrhagic transformation affecting the right frontal, temporal, and parietal regions. In addition, an intracranial infection with SARS-CoV-2 was identified during the rehabilitation process; consequently, an idiopathic subdural effusion developed. Remarkably, the subdural effusion underwent absorption within 6 d, with no recurrence observed during the 3-month follow-up. CONCLUSION: Subdural effusion is a potentially rare intracranial complication associated with SARS-CoV-2 infection.

Free Radicals Generated in Perfluorocarbon-Water (Liquid-Liquid) Interfacial Contact Electrification and Their Application in Cancer Therapy.

Electron transfer during solid-liquid contact electrification has been demonstrated to produce reactive oxygen species (ROS) such as hydroxyl radicals (•OH) and superoxide anion radicals (•O2-). Here, we show that such a process also occurs in liquid-liquid contact electrification. By preparing perfluorocarbon nanoemulsions to construct a perfluorocarbon-water "liquid-liquid" interface, we confirmed that electrons were transferred from water to perfluorocarbon in ultrasonication-induced high-frequency liquid-liquid contact to produce •OH and •O2-. The produced ROS could be applied to ablate tumors by triggering large-scale immunogenic cell death in tumor cells, promoting dendritic cell maturation and macrophage polarization, ultimately activating T cell-mediated antitumor immune response. Importantly, the raw material for producing •OH is water, so the tumor therapy is not limited by the endogenous substances (O2, H2O2, etc.) in the tumor microenvironment. This work provides new perspectives for elucidating the mechanism of generation of free radicals in liquid-liquid contact and provides an excellent tumor therapeutic modality.

Codelivery of CPT and siPHB1 with GSH/ROS Dual-Responsive Hybrid Nanoparticles Based on a [12]aneN3-Derived Lipid for Synergistic Lung Cancer Therapy.

The combination of small-interfering RNA (siRNA)-mediated gene silencing and chemotherapeutic agents for lung cancer treatment has attracted widespread attention in terms of a greater therapeutic effect, minimization of systemic toxicity, and inhibition of multiple drug resistance (MDR). In this work, three amphiphiles, CBN1-CBN3, were first designed and synthesized as a camptothecin (CPT) conjugate and gene condensation agents by the combination of CPT prodrugs and di(triazole-[12]aneN3) through the ROS-responsive phenylborate ester and different lengths of alkyl chains (with 6, 9, 12 carbon chains for CBN1-CBN3, respectively). CBN1-CBN3 were able to be self-assembled into liposomes with an average diameter in the range of 320-240 nm, showing the ability to effectively condense siRNA. Among them, CBN2, with a nine-carbon alkyl chain, displayed the best anticancer efficiency in A549 cells. In order to give nanomedicines a stealth property and PEGylation/dePEGylation transition, a GSH-responsive PEGylated TPE derivative containing a disulfide linkage (TSP) was further designed and prepared. A combination of CBN2/siRNA complexes and DOPE with TSP resulted in GSH/ROS dual-responsive lipid-polymer hybrid nanoparticles (CBN2-DP/siRNA NPs). In present GSH and H2O2, CBN2-DP/siRNA NPs were decomposed, resulting in the controlled release of CPT drug and siRNA. In vitro, CBN2-DP/siPHB1 NPs showed the best anticancer activity for suppression of about 75% of A549 cell proliferation in a serum medium. The stability of CBN2-DP/siRNA NPs was significantly prolonged in blood circulation, and they showed effective accumulation in the A549 tumor site through an enhanced permeability and retention (EPR) effect. In vivo, CBN2-DP/siPHB1 NPs demonstrated enhanced synergistic cancer therapy efficacy and tumor inhibition as high as 71.2%. This work provided a strategy for preparing lipid-polymer hybrid NPs with GSH/ROS dual-responsive properties and an intriguing method for lung cancer therapy.

Multistrand Twisted Triboelectric Kevlar Yarns for Harvesting High Impact Energy, Body Injury Location and Levels Evaluation.

Developing ultrahigh-strength fabric-based triboelectric nanogenerators for harvesting high-impact energy and sensing biomechanical signals is still a great challenge. Here, the constraints are addressed by design of a multistrand twisted triboelectric Kevlar (MTTK) yarn using conductive and non-conductive Kevlar fibers. Manufactured using a multistrand twisting process, the MTTK yarn offers superior tensile strength (372 MPa), compared to current triboelectric yarns. In addition, a self-powered impact sensing fabric patch (SP-ISFP) comprising signal acquisition, processing, communication circuit, and MTTK yarns is integrated. The SP-ISFP features withstanding impact (4 GPa) and a sensitivity and response time under the high impact condition (59.68 V GPa-1 ; 0.4 s). Furthermore, a multi-channel smart bulletproof vest is developed by the array of 36 SP-ISFPs, enabling the reconstruction of impact mapping and assessment of body injury location and levels by real-time data acquisition. Their potential to reduce body injuries, professional security, and construct a multi-point personal vital signs dynamic monitoring platform holds great promise.

Review on the Role of IRF6 in the Pathogenesis of Non-syndromic Orofacial Clefts.

Non-syndromic orofacial clefts (NSOCs) are the most common craniofacial malformation. In the complex aetiology and pathogenesis of NSOCs, genetic factors play a crucial role and IRF6, located at chromosome 1q32.2, is the best documented NSOC susceptibility gene. IRF6 is a key factor in oral maxillofacial development and known to contribute the most in NSOCs. It is essential to conduct a complete review of the existing results on IRF6 to further understand its role in the pathogenesis of NSOCs. Thus, the present authors summarised the research progress on the mechanism of IRF6 in NSOCs from both genetic and functional perspectives in this review.

Spontaneous Wetting Induced by Contact-Electrification at Liquid-Solid Interface.

Wettability significantly influences various surface interactions and applications at the liquid-solid interface. However, the understanding is complicated by the intricate charge exchange occurring through contact electrification (CE) during this process. The understanding of the influence of triboelectric charge on wettability remains challenging, especially due to the complexities involved in concurrently measuring contact angles and interfacial electrical signals. Here, the relationship is investigated between surface charge density and change of contact angle of dielectric films after contact with water droplets. It is observed that the charge exchange when water spared lead to a spontaneous wetting phenomenon, which is termed as the contact electrification induced wetting (CEW). Notably, these results demonstrate a linear dependence between the change of contact angle (CA) of the materials and the density of surface charge on the solid surface. Continuous CEW tests show that not only the static CA but also the dynamics of wetting are influenced by the accumulation charges at the interface. The mechanism behind CEW involves the redistribution of surface charges on a solid surface and polar water molecules within liquid. This interaction results in a decrease in interface energy, leading to a reduction in the CA. Ab initio calculations suggest that the reduction in interface energy may stem from the enhanced surface charge on the substrate, which strengthens the hydrogen bond interaction between water and the substrate. These findings have the potential to advance the understanding of CE and wetting phenomena, with applications in energy harvesting, catalysis, and droplet manipulation at liquid-solid interfaces.

Enhanced Piezoelectricity of MAPbI3 by the Introduction of MXene and Its Utilization in Boosting High-Performance Photodetectors.

Recently, perovskite photodetectors (PDs) are risen to prominence due to substantial research interest. Beyond merely tweaking the composition of materials, a cutting-edge advancement lies in leveraging the innate piezoelectric polarization properties of perovskites themselves. Here, the investigation shows utilizing Ti3C2Tx, a typical MXene, as an intermediate layer for significantly boosting the piezoelectric property of MAPbI3 thin films. This improvement is primarily attributed to the enhanced polarization of the methylammonium (MA+) groups within MAPbI3, induced by the OH groups present in Ti3C2Tx. A flexible PD based on the MAPbI3/MXene heterostructure is then fabricated. The new device is sensitive to a wide range of wavelengths, displays greatly enhanced performance owing to the piezo-phototronic coupling. Moreover, the device is endowed with a greatly reduced response time, down to millisecond level, through the pyro-phototronic effect. The characterization shows applying a -1.2% compressive strain on the PD leads to a remarkable 102% increase in the common photocurrent, and a 76% increase in the pyro-phototronic current. The present work reveals how the emerging piezo-phototronic and pyro-phototronic effects can be employed to design high-performance flexible perovskite PDs.

Research on the Low-Temperature Impact Toughness of a New 100-mm Ultra-Thick Offshore Steel Fabricated Using the Narrow-Gap Laser Wire Filling Welding Process.

Ultra-thick offshore steel, known for its high strength, high toughness, and corrosion resistance, is commonly used in marine platforms and ship components. However, when offshore steel is in service for an extended period under conditions of high pressure, extreme cold, and high-frequency impact loads, the weld joints are prone to fatigue failure or even fractures. Addressing these issues, this study designed a narrow-gap laser wire filling welding process and successfully welded a 100-mm new type of ultra-thick offshore steel. Using finite element simulation, EBSD testing, SEM analysis, and impact experiments, this study investigates the weld's microstructure, impact toughness, and fracture mechanisms. The research found that at -80 °C, the welded joint exhibited good impact toughness (>80 J), with the impact absorption energy on the surface of the weld being 217.7 J, similar to that of the base material (225.3 J), and the fracture mechanism was primarily a ductile fracture. The impact absorption energy in the core of the weld was 103.7 J, with the fracture mechanism mainly being a brittle fracture. The EBSD results indicated that due to the influence of the welding thermal cycle and the cooling effect of the narrow-gap process, the grains gradually coarsened from the surface of the welded plate to the core of the weld, which was the main reason for the decreased impact toughness at the joint core. This study demonstrates the feasibility of using narrow-gap laser wire filling welding for 100-mm new type ultra-thick offshore steel and provides a new approach for the joining of ultra-thick steel plates.

Ionic Rectification by Dynamic Regulation of the Electric Double Layer at the Hydrogel Interface.

Hydrogels play a pivotal role in the realm of iontronics, contributing to the realization of futuristic human-machine interactions. The electric double layer (EDL) between the hydrogel and electrode provides an essential ionic-electronic coupling interface. While prior investigations primarily delved into elucidating the formation mechanism of the EDL, our study shifts the focus to showcasing the current generation through the mechanical modulation of the EDL at the hydrogel-metal interfaces. The dynamic EDL was constructed by the mechano-driven contact-separation process between the polyacrylamide (PAAm) hydrogel and Au. Influencing factors on the dynamic regulation of the EDL such as ion concentration, types of salt, contact-separation frequency, and deformation degree were investigated. Dehydration usually limits the practical applications of hydrogels, and it is a long-standing and difficult problem. However, it seemed to be able to slow the EDL formation process here, resulting in a sustained continuous direct current signal output. Such hydrogel iontronics could rectify the displacement electronic current of a triboelectric nanogenerator by the ionic current. The directional migration of ions could be further enhanced by using charge-collecting metals with different work functions, for example, Au and Al. It offers a paradigm to enable ionic rectification that could be seamlessly incorporated into electronic systems, ushering in a new era for efficient energy harvesting and biomimetic nervous systems.

Drug resistance in ovarian cancer: from mechanism to clinical trial.

Ovarian cancer is the leading cause of gynecological cancer-related death. Drug resistance is the bottleneck in ovarian cancer treatment. The increasing use of novel drugs in clinical practice poses challenges for the treatment of drug-resistant ovarian cancer. Continuing to classify drug resistance according to drug type without understanding the underlying mechanisms is unsuitable for current clinical practice. We reviewed the literature regarding various drug resistance mechanisms in ovarian cancer and found that the main resistance mechanisms are as follows: abnormalities in transmembrane transport, alterations in DNA damage repair, dysregulation of cancer-associated signaling pathways, and epigenetic modifications. DNA methylation, histone modifications and noncoding RNA activity, three key classes of epigenetic modifications, constitute pivotal mechanisms of drug resistance. One drug can have multiple resistance mechanisms. Moreover, common chemotherapies and targeted drugs may have cross (overlapping) resistance mechanisms. MicroRNAs (miRNAs) can interfere with and thus regulate the abovementioned pathways. A subclass of miRNAs, "epi-miRNAs", can modulate epigenetic regulators to impact therapeutic responses. Thus, we also reviewed the regulatory influence of miRNAs on resistance mechanisms. Moreover, we summarized recent phase I/II clinical trials of novel drugs for ovarian cancer based on the abovementioned resistance mechanisms. A multitude of new therapies are under evaluation, and the preliminary results are encouraging. This review provides new insight into the classification of drug resistance mechanisms in ovarian cancer and may facilitate in the successful treatment of resistant ovarian cancer.