9 research outputs found

    Hydrogel-based treatments for spinal cord injuries

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    Spinal cord injury (SCI) is characterized by damage resulting in dysfunction of the spinal cord. Hydrogels are common biomaterials that play an important role in the treatment of SCI. Hydrogels are biocompatible, and some have electrical conductivity that are compatible with spinal cord tissues. Hydrogels have a high drug-carrying capacity, allowing them to be used for SCI treatment through the loading of various types of active substances, drugs, or cells. We first discuss the basic anatomy and physiology of the human spinal cord and briefly discuss SCI and its treatment. Then, we describe different treatment strategies for SCI. We further discuss the crosslinking methods and classification of hydrogels and detail hydrogel biomaterials prepared using different processing methods for the treatment of SCI. Finally, we analyze the future applications and limitations of hydrogels for SCI. The development of biomaterials opens up new possibilities and options for the treatment of SCI. Thus, our findings will inspire scholars in related fields and promote the development of hydrogel therapy for SCI

    Rectifier Current Control for an LLC Resonant Converter Based on a Simplified Linearized Model

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    In this paper, a rectifier current control for an LLC resonant converter is proposed, based on a simplified, two-order, linearized model that adds a rectifier current feedback inner loop to improve dynamic performance. Compared to the traditional large-signal model with seven resonant states, this paper utilizes a rectifier current state to represent the characteristics of the resonant states, simplifying the LLC resonant model from seven orders to two orders. Then, the rectifier current feedback inner loop is proposed to increase the control system damping, improving dynamic performance. The modeling and design methodology for the LLC resonant converter are also presented in this paper. A frequency analysis is conducted to verify the accuracy of the simplified model. Finally, a 200 W LLC resonant converter prototype is built to verify the effectiveness of the proposed control strategy. Compared to a traditional single-loop controller, the settling time and voltage droop were reduced from 10.8 ms to 8.6 ms and from 6.8 V to 4.8 V, respectively, using the proposed control strategy

    Zn2+ incorporated composite polysaccharide microspheres for sustained growth factor release and wound healing

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    The development of new wound dressings has always been an issue of great clinical importance and research promise. In this study, we designed a novel double cross-linked polysaccharide hydrogel microspheres based on alginate (ALG) and hyaluronic acid methacrylate (HAMA) from gas-assisted microfluidics for wound healing. The microspheres from gas-assisted microfluidics showed an uniform size and good microsphere morphology. Moreover, this composite polysaccharide hydrogel microspheres were constructed by harnessing the fact that zinc ions (Zn2+) can cross-link with ALG as well as histidine-tagged vascular endothelial growth (His-VEGF) to achieve long-term His-VEGF release, thus promoting angiogenesis and wound healing. Meanwhile, Zn2+, as an important trace element, can exert antibacterial and anti-inflammatory effects, reshaping the trauma microenvironment. In addition, photo cross-linked HAMA was introduced into the microspheres to further improve its mechanical properties and drug release ability. In summary, this novel Zn2+ composite polysaccharide hydrogel microspheres loaded with His-VEGF based on a dual cross-linked strategy exhibited synergistic antimicrobial and angiogenic effects in promoting wound healing

    Energy Feedback Control of Light-Load Voltage Regulation for LLC

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    Longer time spent in bed attempting to sleep is associated with rapid renal function decline: the Dongfeng–Tongji cohort study

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    <p><b>Introduction:</b> Prospective evidence on the relation between time in bed and renal dysfunction remains limited. We aimed to investigate the association of time spent in bed attempting to sleep (TSBS) with renal function decline in a middle-aged and elderly Chinese population.</p> <p><b>Methods:</b> About 16,733 eligible participants with a mean age of 62.3 years at baseline were included. Rapid renal function decline was defined as (baseline eGFR − revisit eGFR)/years of follow-up ≥5 mL/min per 1.73 m<sup>2</sup>/year. A total of 1738 study participants experienced rapid renal function decline after a median 4.6-year follow-up. Logistic regression models were used for multivariate analyses.</p> <p><b>Results:</b> The adjusted odds ratio (OR) of rapid renal function decline was 1.18 (95% CI: 1.02, 1.37) for TSBS ≥9 h/night compared with TSBS 7 to <8 h/night. This association remained significant (OR = 1.19, 95% CI: 1.03, 1.38) after further adjustment for sleep quality, midday napping and usage of sleeping pills. Particularly, the association appeared to be prominent in individuals with diabetes.</p> <p><b>Conclusions:</b> Longer TSBS (≥9 h) was independently associated with an increased risk of rapid renal function decline. Our findings emphasized the importance to have optimal TSBS.Key messages</p><p>Our study firstly investigated the association between time spent in bed attempting to sleep (TSBS) and renal dysfunction in Chinese adults.</p><p>Compared with individuals TSBS 7 to <8 h, individuals with TSBS ≥9 h had 19% increased risk for rapid renal function decline after adjustment for multivariate confounders.</p><p>The association appeared to be prominent in individuals with diabetes.</p><p></p> <p>Our study firstly investigated the association between time spent in bed attempting to sleep (TSBS) and renal dysfunction in Chinese adults.</p> <p>Compared with individuals TSBS 7 to <8 h, individuals with TSBS ≥9 h had 19% increased risk for rapid renal function decline after adjustment for multivariate confounders.</p> <p>The association appeared to be prominent in individuals with diabetes.</p

    Direct, indirect and total bilirubin and risk of incident coronary heart disease in the Dongfeng-Tongji cohort

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    <p><b>Background:</b> Total bilirubin (TBIL) is known to be inversely associated with coronary heart disease (CHD) risk, however, whether this association is dose-response remains inconsistent and it is unclear which subtype of bilirubin is responsible for the potential protective effect.</p> <p><b>Methods:</b> We included 12,097 participants who were free of CHD, stroke, cancer and potential liver, biliary and renal diseases at baseline from September 2008 to June 2010 and were followed-up until October 2013. Cox proportional hazards models were used to assess the hazard ratios (HR) and 95% confidence interval (95% CI) of bilirubin with incident CHD risk.</p> <p><b>Results:</b> The adjusted HRs for incident CHD increased with increasing direct bilirubin (DBIL) (<i>p</i> for trend = .013). Participants within the highest quintile of DBIL had 30% higher risk of incident CHD compared to those in the lowest quintile (95% CI: 1.07, 1.58). In contrast, compared with subjects in the lowest quintile of TBIL, those in the third quintile had the lowest of 24% risk for CHD incidence (95% CI: 0.63, 0.92), which showed a U-shaped association (<i>p</i> for quadratic trend = .040).</p> <p><b>Conclusions:</b> DBIL was associated with a dose-response increased risk for CHD incidence. However, a U-shaped association existed between TBIL, indirect bilirubin and incident CHD risk.Key messages</p><p>Direct bilirubin is independently associated with incident coronary heart disease (CHD) in a dose-response manner.</p><p>A similarly consistent U-shaped association was found between total bilirubin, indirect bilirubin and incident CHD.</p><p>The potential protective effect of total bilirubin within the normal range on incident CHD should be mainly attributed to mild-to moderate elevated levels of indirect bilirubin.</p><p></p> <p>Direct bilirubin is independently associated with incident coronary heart disease (CHD) in a dose-response manner.</p> <p>A similarly consistent U-shaped association was found between total bilirubin, indirect bilirubin and incident CHD.</p> <p>The potential protective effect of total bilirubin within the normal range on incident CHD should be mainly attributed to mild-to moderate elevated levels of indirect bilirubin.</p
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