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Hydrogels have attracted widespread attention for breaking the bottlenecks faced during facile drug delivery. To date, the preparation of jelly carriers for hydrophobic drugs remains challenging. In this study, by evaporating ethanol to drive the formation of hydrogen bonds, hydrophilic poly(vinyl alcohol) (PVA) and certain hydrophobic compounds [luteolin (LUT), quercetin (QUE), and myricetin (MYR)] were rapidly prepared into supramolecular hydrogel within 10 min. The gelation performance of these three hydrogels changed regularly with the changing sequence of LUT, QUE, and MYR. An investigation of the gelation pathway of these hybrid gels reveals that the formation of this type of gel follows a simple supramolecular self-assembly process, called "hydrophobe-hydrophile crosslinked gelation". Because the hydrogen bond between PVA and the drug is noncovalent and reversible, the hydrogel has good plasticity and self-healing properties, while the drugs can be controllably released by tuning the output stimuli. Using a rat sidewall-cecum abrasion adhesion model, the as-prepared hydrogel was highly efficient and safe in preventing postsurgical adhesion. This work provides a useful archetypical template for researchers interested in the efficient delivery and controllable release of hydrophobic drugs.

A multi-exposures with dose modulation method is presented to fabricate SU-8 mold which is used for microfluidic channels. The method used a maskless digital lithography device with a 405 nm LED source. Digital micromirror device (DMD) maskless lithograph can reach higher precision to meet the requirements of microfluidic chips. For a thick SU-8 layer, multi-exposures with low dose method can effectively suppress the T-shaped structure formed due to top overexposed and bottom underexposed. Two SU-8 molds were fabricated with 55 μm and 25 μm in height in this work. The number of exposures is 62 and 55, respectively. The actual contour of SU-8 structures closely matches the design contour. The PDMS microchannel structure was fabricated using the SU-8 mold. The minimum width of a single microchannel achieved 10 μm. This method provides a more flexible method for fabricating SU-8 molds with higher precision and is well suited for on-chip cell isolation.

Clinically, increasing the peritoneal barrier is an effective adjunct to reducing postoperative peritoneal adhesion. This study presents a facile template for preparing a supramolecular hybrid hydrogel through dynamic covalent cross-linking between carboxymethyl chitosan (CMCS), 2-formylphenylboronic acid (2-FPBA), and quercetin (Que). The as-prepared complex CMCS/2-FPBA/Que (CFQ) hydrogel exhibited favorable antibacterial, anti-inflammatory, and antioxidant effects. A L929 cytotoxicity evaluation confirmed the favorable cytocompatibility of the CFQ hydrogel. The postoperative anti-adhesion ability of the CFQ hydrogel was further evaluated in rats with lateral wall defects and cecal abrasions. Compared with control groups, the tissue adhesion rate was significantly reduced by increasing the Que concentration in all the hydrogel-treated groups. Additionally, the sustained-release time of the C3F0.8Q0.08 hydrogel can exceed 14 days, which is highly desirable for clinical wound treatment. STATEMENT OF SIGNIFICANCE: Postoperative adhesions are a very common postoperative complication that seriously affects the quality of life of patients. The currently commonly used methods for preventing adhesion mainly use degradable barrier materials for physical separation. In this study, we prepared a dual dynamic covalently cross-linked CFQ hydrogel, which is not only degradable and injectable, but also has multiple properties such as antibacterial, antioxidant and anti-inflammatory, which can effectively prevent postoperative adhesion and promote wound healing.

The in situ polymerization of monomers to form a second network within a preexisting network (first network) is a facile and effective strategy to fabricate semi-interpenetrating (semi-IPN) hydrogels with enhanced mechanical strength; while to comprehend the effects of the first polymer network on the polymerization process of the second network is still a challenging project. This paper introduces a simple method of employing dynamic rheological measurement loops to monitor the real time progress of the in situ polymerized acrylamide (AAm) in a chitosan (CS) solution towards the formation of a semi-IPN hydrogel. To identify the effects of the preexisting network on the polymerization gelation process, the concept “Effective Conversion Ratio (ECR)” is introduced to evaluate the first network effects on the requirement for the polymerized conversion ratio of the second network to form a critical gel. The rheological properties before gel point, at gel point, and at post-gel stage are discussed via the obtained real time data, respectively. The experimental results have proved the suitability of utilizing dynamic rheology to obtain the real time details of the semi-IPN gel fabrication process.

Hydrogels have been widely applied in the fields of biology, medicine, soft materials and flexible/wearable devices owing to their superior biocompatibility and their versatile physicochemical properties. Although multiple chemical and physical methods have been proposed to functionalize hydrogels, endowing hydrogels with multi-properties/functionalities utilizing few components is still a challenge. This paper describes a simple and effective method to functionalize polymeric hydrogels with carboxymethyl cellulose (CMC) modified Fe3O4 nanoparticles (CMC@Fe3O4 NPs). The as-prepared metallogels exhibit good self-healing ability, ionic conductivity, photo-thermal transformability and magnetic field responsiveness. A triple functional sensor was built up to prove the universal viability of this metallogel toward functional devices.

Objective: We investigated the relationship between impulsivity, as measured by delay and probability discounting, and gambling-related cognitions and behavior in adults with and without ADHD. Method: Adults who met Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) diagnostic criteria for ADHD (n = 31) and controls (n = 29) were recruited from the community. All completed an interview that included an assessment of psychiatric disorders, gambling questionnaires, and simulated gambling, delay, and probability discounting tasks. Results: The ADHD group was more likely to meet the criteria for problem gambling and was more impulsive than controls based on a composite discounting measure. ADHD symptoms were correlated with gambling-related cognitions and behavior. Probability, but not delay discounting, explained significant variance in gambling-related measures after controlling for ADHD symptoms. Discussion: Results confirm an association between adult ADHD and gambling, and suggest that the facets of impulsivity related to risk proneness may be an independent risk factor for problem gambling in this population. (J. of Att. Dis. XXXX; XX(X) 1-XX)

Abnormal aggregation of amyloid-β (Aβ) particles and oxidative stress are pathological hallmarks of Alzheimer’s disease (AD). Quercetin (Que), a flavonoid antioxidant, has been widely used to inhibit Aβ fibril formation and can potentially attenuate oxidative stress. However, poor aqueous solubility, extensive first-pass metabolism, and low permeability of the blood-brain barrier (BBB) limit its clinical application. Herein, we introduce a simple strategy to develop nanocomposites (NC) for drug delivery. This method involves combining Que and Na2SeO3 to obtain selenium nanoparticles. These nanoparticles are then modified using a combination of acacia and polysorbate 80 (P80-Que@Se NC). This recently developed nanocomposite has the potential to enhance drug delivery across the blood-brain barrier (BBB) and polysorbate 80 act as a pharmaceutical excipient that increases the aqueous solubility of Que. In vitro results demonstrated that P80-Que@Se had high aqueous solubility compared to individual Que, and could effectively inhibit Aβ fibrillation. In vitro Cell Counting Kit (CCK)-8 analysis indicated that P80-Que@Se nanocomposites could protect PC12 cells from H2O2-induced cell death. Additionally, P80-Que@Se had high 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and exhibited excellent antioxidant activity. This study suggested that P80-Que@Se NCs may aid in the treatment of AD and have broad implications for future NC-based studies and applications. In brief, we believe that this reliable drug delivery method will serve as a useful template for researchers designing therapies to be delivered across the BBB.

The chitosan-based hydrogel dressings have been intensively engaged in wound healing. In respect to the relatively unsatisfied anti-bacterial performance of chitosan, we developed a self-healable cordycepin (abbreviated to CY)/chitosan (abbreviated to CS) hydrogel dressing cross linking by non-covalent bonds (hydrogen bond and electrostatic interaction) for wound healing through one-step ‘freeze-thaw’ method without adding any cross-linking agent. The as-prepared hybrid hydrogel exhibited excellent biocompatibility, suitable swelling ratio and desired mechanical strength, providing remarkable antimicrobial effect with no side effects in vitro. The self-healable property enables this hydrogel to adapt irregularly shaped wound defects without premolding. Moreover, our in vivo experiments confirmed that CY/CS hydrogel served as a quicker re-epithelization of skin wounds and an apparent increasing collagen deposition compared with chitosan hydrogels. Additionally, the CY/CS hydrogel significantly increased the expressions of epithelial regeneration markers including laminin and involucrin. The present study highlights a facile hydrogel strategy to balance and optimize the biocompatibility, swelling ratio and self-adapting ability for treating wound healing.

In order to reduce the current of each IGBT and reduce the harmonic current into the grid, a multiple AC-DC-AC full-scale converter which is suitable for high power direct drive wind power generation systems is adopted. The reasons of DC-link voltage fluctuation of the grid connected converter are analyzed. An improved DC-link voltage control method for multiple grid connected converter in direct drive wind power generation systems is proposed in this paper to limit the fluctuation range of the DC-link voltage. The instantaneous generator power and grid voltage feedbacks are used to improve the dynamic response of the DC-link voltage. Simulation and experimental results verify the analysis and the conclusion.

In the high power direct drive wind energy conversion systems, the power factors of both the generator-side converter and the grid-side converter are controlled to one in order to make full use of the capability of the power converters. In this paper, a novel sensorless unity power factor control method based on the reference coordinate system rotating synchronously with the voltage of the generator-side converter is proposed to estimate the rotor speed of the six-phase PMSG. This method is very simple and only needs the measurement of the voltage phase of the generator-side converter. The power factor of the generator-side converter can be controlled to one easily and it can increase the capability of the converter. Simulation and experimental results verify the analysis and the conclusion.

For 4 wire VSI, Under unbalanced grid voltage conditions, neutral currents that flow through the fourth wire will distort the symmetrical output voltage. And dc link voltage ripple will be produced. We introduced a three reference frame scheme to eliminate the dc link voltage ripple and output voltage distortion. Unbalanced grid voltage and ac link current are decomposed into positive, negative and zero sequence components. Positive sequence components is regulated in a positive synchronous reference frame (SRF), negative sequence components is regulated in a negative SRF, and zero sequence components is regulated in a zero SRF. In positive SRF, positive components appear as dc, while negative components appear as 2? rad/s. In contrast, in negative SRF, negative components appear as dc, while positive sequence appear as 2? rad/s. Zero sequence composents will not have any impace on dq, it appears as a disturbance in the o-variable at the fundamental frequency. In order to eleminated the dc link voltage ripple and output voltage distortion, positive, negative and zero sequence components shoud be controlled simultaneously. Simulation and experimental results are presented to verify the validity of the proposed control scheme.