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1.
The foreign body reaction to neuronal electrode implants limits potential applications as well as the therapeutic period. Developments in the basic electrode design might improve the tissue compatibility and thereby reduce the foreign body reaction. In this work, the approach of embedding 3D carbon nanofiber electrodes in extracellular matrix (ECM) synthesized by human fibroblasts for a compatible connection to neuronal cells was investigated. Porous electrode material was manufactured by solution coelectrospinning of polyacrylonitrile and polyamide as a fibrous porogen. Moreover, NaCl represented an additional particulate porogen. To achieve the required conductivity for an electrical interface, meshes were carbonized. Through the application of two different porogens, the electrodes’ flexibility and porosity was improved. Human dermal fibroblasts were cultured on the electrode surface for ECM generation and removed afterwards. Scanning electron microscopy imaging revealed a nano fibrous ECM network covering the carbon fibers. The collagen amount of the ECM coating was quantified by hydroxyproline-assays. The modification with the natural protein coating on the electrode functionality resulted in a minor increase of the electrical capacity, which slightly improved the already outstanding electrical interface properties. Increased cell numbers of SH-SY5Y cell line on ECM-modified electrodes demonstrated an improved cell adhesion. During cell differentiation, the natural ECM enhanced the formation of neurites regarding length and branching. The conducted experiments indicated the prevention of direct cell-electrode contacts by the modification, which might help to shield temporary the electrode from immunological cells to reduce the foreign body reaction and improve the electrodes’ tissue integration. 相似文献
2.
An effective method for levulinic acid esters synthesis by the enzymatic Fischer esterification of levulinic acid using a lipase B from Candida antarctica (CALB) immobilized on the advanced material consisting of multi-wall carbon nanotubes (MWCNTs) and a hydrophobic polymer—polytetrafluoroethylene (Teflon, PTFE)—as a heterogeneous biocatalyst, was developed. An active phase of the biocatalyst was obtained by immobilization via interfacial activation on the surface of the hybrid material MWCNTs/PTFE (immobilization yield: 6%, activity of CALB: 5000 U∙L∙kg−1, enzyme loading: 22.5 wt.%). The catalytic activity of the obtained biocatalyst and the effects of the selected reaction parameters, including the agitation speed, the amount of PTFE in the CALB/MWCNT-PTFE biocatalyst, the amount of CALB/MWCNT-PTFE, the type of organic solvent, n-butanol excess, were tested in the esterification of levulinic acid by n-butanol. The results showed that the use of a two-fold excess of levulinic acid to n-butanol, 22.5 wt.% of CALB on MWCNT-PTFE (0.10 wt.%) and cyclohexane as a solvent at 20 °C allowed one to obtain n-butyl levulinate with a high yield (99%) and selectivity (>99%) after 45 min. The catalyst retained its activity and stability after three cycles, and then started to lose activity until dropping to a 69% yield of ester in the sixth reaction run. The presented method has opened the new possibilities for environmentally friendly synthesis of levulinate esters. 相似文献
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Rationale:Carbon dioxide pneumoperitoneum in laparoscopic surgery can bring about occult perioperative cerebral infarction, advancing our understanding of the causes of severe postoperative delayed recovery.Patient concerns:Here, we report the case of a 35-year-old woman who underwent a right renal tumor resection in our institution, during which a raised pneumoperitoneum pressure (from 15 to 20 mm Hg) was adopted by the surgeon to prevent errhysis and to help stop the bleeding. Despite an accidental minor tearing of the inferior vena cava, vital signs remained stable throughout the procedure, and no obvious abnormality was observed in either end tidal carbon dioxide values or blood gas analysis. However, the patient unexpectedly suffered delayed recovery after the operation, presenting incomplete left hemiplegia and a positive Babinski sign.Diagnoses:Perioperative stroke was diagnosed by anesthesiologists, after excluding the effects of anesthesia. Cerebral hemorrhage was excluded, as no obvious abnormality was found in the density of brain parenchyma in the emergency computed tomography examination, and a digital subtraction angiography showed no abnormal thrombosis. Further magnetic resonance diagnosis led us to consider diffuse gas embolisms to be the cause of this acute stroke; a right echocardiography revealed that a patent foramen ovale (PFO) may account for the global cerebral gas embolisms.Interventions:The patient received neuroprotective drugs (Vinpocetine, Edaravone, and Xingnaojing, which are commonly used as a standard of care in China), antiplatelets and other symptomatic treatments, plus dexamethasone to relieve edema. A contrast-enhanced echocardiography of the right heart was performed, the results of which were consistent with the sonography of a PFO.Outcomes:The patient was hospitalized for 14 days and eventually discharged after recovery. At the latest follow-up in August 2019, the patient recovered without residual neurological sequelae.Lessons:Our results emphasize the need for vigilance regarding adverse cardiovascular and neurological events caused by carbon dioxide gas embolisms when encountering the inadvertent situation of vessels rupturing. Timely monitoring of paradoxical gas embolism by transoesophageal echocardiography is necessary and can avert the risk of severe complications. Urgent consideration should be given to stopping pneumoperitoneum and switching to laparotomy for hemostasis so that the patient can obtain the best benefit–risk ratio. 相似文献
5.
Zahraa Kansoun Hicham Chaouki Donald Picard Julien Lauzon-Gauthier Houshang Alamdari Mario Fafard 《Materials》2021,14(4)
Carbon-like materials such as the anode and the ramming paste play a crucial role in the efficiency of the Hall–Héroult process. The mechanical behavior of these materials during forming processes is complex and still ill-understood. This work aimed to investigate experimentally the mechanical behavior of a carbon paste used in the aluminum industry under different loading conditions. For this purpose, experiments consisting of (1) relaxation tests at different compaction levels, (2) quasi-static cyclic tests at several amplitudes, (3) monotonic compaction tests at varied strain rates, and (4) vibrocompaction tests at different frequencies were carried out. The obtained results highlight some fundamental aspects of the carbon paste behavior such as the strain rate’s effect on the paste compressibility, the hardening-softening behavior under cyclic loadings, the effect of cycling amplitude on the stress state and the paste densification, and the frequency effect on the vibrocompaction process. These results pave the way for the development of reliable rheological models for the modeling and the numerical simulation of carbon pastes forming processes. 相似文献
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目的研究利用经聚乙烯亚胺(PEI)钝化的荧光碳点(CD)装载阿霉素(DOX)进行药物递送,旨在增加DOX对非小细胞肺癌的治疗作用,减少DOX的心肌毒性。 方法通过一步微波加热法将甘油和PEI的混合物制备成CD-PEI,并通过静电效应将DOX装载至CD-PEI。采用CCK8实验检测CD-PEI-DOX对非小细胞肺癌细胞A549的增殖能力的影响;Transwell实验评估CD-PEI-DOX对A549细胞迁移侵袭能力的影响;最后通过体内动物实验评估CD-PEI-DOX的心肌毒性以及对非小细胞肺癌皮下肿瘤生长的抑制效果。 结果体外细胞实验证实,对比单纯的DOX处理组,CD-PEI-DOX对非小细胞肺癌A549细胞增殖、迁移侵袭能力的抑制作用更为显著。体内实验证实,CD-PEI-DOX纳米复合物治疗组小鼠心肌细胞结构完整,并且能有效抑制小鼠皮下肺癌肿瘤的生长。 结论经PEI钝化的荧光碳点负载阿霉素能显著提高DOX对非小细胞肺癌的治疗效果,并减少DOX对心脏的毒性作用。运用CD-PEI纳米颗粒改善化疗药物递送的治疗方案取得了初步证实,这可为肺癌化学治疗提供新思路,具有广大的临床应用前景。 相似文献
8.
目的 探究超脉冲二氧化碳点阵激光治疗稳定期白癜风的临床效果。方法 以我院2019年1月-2020年10月收治的80例稳定期白癜风患者为研究对象,通过简单随机化法分为对照组(n=40)和试验组(n=40),对照组采用常规药物治疗,试验组则在对照组基础实施超脉冲二氧化碳点阵激光治疗,比较两组治疗效果、生活质量评分、炎性因子水平及不良反应发生情况。结果 试验组的总有效率为90.00%,高于对照组的70.00%(P<0.05);两组治疗后生活质量评分均高于治疗前,且试验组生活质量评分高于对照组(P<0.05);两组炎性因子水平均低于治疗前,且试验组低于对照组(P<0.05);两组不良反应发生率比较,差异无统计学意义(P>0.05)。结论 与常规药物治疗相比,超脉冲二氧化碳点阵激光治疗效果更佳,可有效改善患者生活质量,降低炎性因子水平,且不会增加不良反应,是一种安全、有效的治疗方案。 相似文献
9.
S. M. White C. L. Shelton A. W. Gelb C. Lawson F. McGain J. Muret J. D. Sherman representing the World Federation of Societies of Anaesthesiologists Global Working Group on Environmental Sustainability in Anaesthesia 《Anaesthesia》2022,77(2):201-212
The Earth’s mean surface temperature is already approximately 1.1°C higher than pre-industrial levels. Exceeding a mean 1.5°C rise by 2050 will make global adaptation to the consequences of climate change less possible. To protect public health, anaesthesia providers need to reduce the contribution their practice makes to global warming. We convened a Working Group of 45 anaesthesia providers with a recognised interest in sustainability, and used a three-stage modified Delphi consensus process to agree on principles of environmentally sustainable anaesthesia that are achievable worldwide. The Working Group agreed on the following three important underlying statements: patient safety should not be compromised by sustainable anaesthetic practices; high-, middle- and low-income countries should support each other appropriately in delivering sustainable healthcare (including anaesthesia); and healthcare systems should be mandated to reduce their contribution to global warming. We set out seven fundamental principles to guide anaesthesia providers in the move to environmentally sustainable practice, including: choice of medications and equipment; minimising waste and overuse of resources; and addressing environmental sustainability in anaesthetists’ education, research, quality improvement and local healthcare leadership activities. These changes are achievable with minimal material resource and financial investment, and should undergo re-evaluation and updates as better evidence is published. This paper discusses each principle individually, and directs readers towards further important references. 相似文献
10.
《Vaccine》2019,37(44):6696-6706
Live attenuated viral vaccine/vector candidates are inherently unstable and infectivity titer losses can readily occur without defining appropriate formulations, storage conditions and clinical handling practices. During initial process development of a candidate vaccine against HIV-1 using a recombinant Human Cytomegalovirus vector (rHCMV-1), large vector titer losses were observed after storage at 4 °C and after undergoing freeze-thaw. Thus, the goal of this work was to develop candidate frozen liquid formulations of rHCMV-1 with improved freeze-thaw and short-term liquid stability for potential use in early clinical trials. To this end, a virus stability screening protocol was developed including use of a rapid, in vitro cell-based immunofluorescence focus assay to quantitate viral titers. A library of ∼50 pharmaceutical excipients (from various known classes of additives) were evaluated for their effect on vector stability after freeze-thaw cycling or incubation at 4 °C for several days. Certain additives including sugars and polymers (e.g., trehalose, sucrose, sorbitol, hydrolyzed gelatin, dextran 40) as well as removal of NaCl (lower ionic strength) protected rHCMV-1 against freeze-thaw mediated losses in viral titers. Optimized solution conditions (e.g., solution pH, buffers and sugar type) slowed the rate of rHCMV-1 titer losses in the liquid state at 4 °C. After evaluating various excipient combinations, three new candidate formulations were designed and rHCMV-1 stability was benchmarked against both the currently-used and a previously reported formulation. The new candidate formulations were significantly more stable in terms of reducing rHCMV-1 titer losses after 5 freeze-thaw cycles or incubation at 4 °C for 30 days. This case study highlights the utility of semi-empirical design of frozen liquid formulations of a live viral vaccine candidate, where protection against infectivity titer losses due to freeze-thaw and short-term liquid storage are sufficient to enable more rapid initiation of early clinical trials. 相似文献