固定化血红蛋白氧载体的研究（Ⅱ）：氧化纤维素共价键联 …

以纤维素为载体，经高碘酸钠氧化后共价键联血红蛋白，制备氧载体。研究了氧化条件对血红蛋白固定量的影响。纤维素只有经过预氧化，碱处理和再氧化三步活化反应，才能使血红蛋白大量化，每克纤维素固定血红蛋白量达１．０ｇ。氧载体稳定性好，血红蛋白不脱落。经铁氰化钾氧化，氧载体放氧效率为３３．１％。     

固定化血红蛋白氧载体的研究(Ⅱ)——氧化纤维素共价键联血红蛋白

以纤维素为载体,经高碘酸钠氧化后共价键联血红蛋白,制备氧载体.研究了氧化条件对血红蛋白固定量的影响.纤维素只有经过预氧化、碱处理和再氧化三步活化反应,才能使血红蛋白大量固定化,每克纤维素固定血红蛋白量达1.0g.氧载体稳定性好,血红蛋白不脱落.经铁氰化钾氧化,氧载体放氧效率为33.1%.     

三氯乙酸沉淀法结合姜黄素法测定血红蛋白氧载体中残余硼

建立了一种三氯乙酸沉淀法结合姜黄素法测定血红蛋白氧载体中硼残余含量的方法.以血红蛋白氧载体:三氯乙酸=9:1(V/V)的比例用三氯乙酸沉淀血红蛋白氧载体中聚合血红蛋白,离心5000 g×10 min将溶液中的沉淀分离,获得游离硼化物,聚合血红蛋白沉淀引起体积的缺失由生理盐水补齐,依次加入硫酸冰乙酸混合酸、姜黄素冰乙酸溶...     

固定化血红蛋白氧载体的研究 I.聚乙烯醇包埋血红蛋白

固定化血红蛋白可以作为氧载体，从海水中提取氧气，为人类在水下活动提供氧源。以聚乙烯醇为载体材料，固定化血红蛋白，制备氧载体。研究了该氧载体的氧解离性能以及戊二醛和六磷酸肌醇对氧载体氧解离性能的影响。血红蛋白的固定量达０．６ｇ／ｇ，氧化法测得氧载体的氧解离率为５３．３％。戊二醛后交联提高了氧载体的稳定性。六磷酸肌醇使氧解离率由２４．８％提高到６０．０％。     

130名哈萨克族牧民血清铁、血红蛋白含量与高血压关系的分析

为探讨乌鲁木齐南山130名哈萨克族牧民血清铁及血红蛋白含量与原发性高血压的关系,给哈萨克族原发性高血压的病因学研究提供科学依据,对这些牧民进行了血压测定和血清铁、血红蛋白含量分析。结果表明,130名哈萨克族牧民高血压检出率为53.3%;高血压组血清铁水平明显高于正常组(P=0.000);高血压组血红蛋白含量也明显高于正常组(P=0.004);进一步分析表明,高血压组男性和女性血清铁水平明显高于正常组男性和女性(P0.01和P0.001);血红蛋白含量高血压组女性较正常血压组女性高,差异有统计学意义(P0.05),而男性两组差异不明显。提示哈萨克族高血压患者血清铁和血红蛋白的含量与高血压的发生可能有关。     

人工氧载体研究进展

血液需求的激增和异体输血的不安全性等问题的出现,促使人们合成“血液替代品”。通过对天然氧载体(即血红蛋白)结构与性能的清晰认识,已有多种人工氧载体被成功合成,并应用于临床试验。人工氧载体可分为全氟碳化合物、血红蛋白基氧载体、合成血红素及其高分子配合物三大类。全氟碳化合物虽大部分已退出人工血液市场,但因其具有治疗作用,研究工作仍在进行。为了降低血红蛋白基氧载体的副作用,已采用多种方法对血红蛋白进行改性,如采用化学修饰、微囊包裹(HbV)、重组和仿生纳米等技术。其中,血红蛋白囊泡模拟红细胞的结构,其粒径相对较大(250nm),副作用相对较低,是目前血红蛋白基氧载体的发展趋势。人工合成血红素如栏式卟啉只溶于有机溶剂,为增加其水溶性,可使其与白蛋白、木糖醇酶和环糊精等高分子结合为配合物,经动物实验表明,这些高分子金属配合物在体内具有运送氧气功能。除主要在临床上用作血液代替品外,人工氧载体还在肿瘤治疗、器官移植和缺血/再灌注损伤的预防等方面具有重要的临床应用价值。     

铈基复合氧化物中晶格氧用于甲烷部分氧化制合成气

采用共沉淀法制备了Ce-M-O氧载体（M＝Fe、Mn、Cu）,并进行了XRD表征。研究了Ce-M-O中晶格氧部分氧化甲烷制合成气的反应。考察了再生时间、再生温度对氧载体部分氧化甲烷性能的影响。研究结果表明, Ce-Fe-O固溶体中的晶格氧适于部分氧化甲烷制合成气。在新鲜的Ce Fe O氧载体上存在少量的强氧化物种,导致开始阶段大部分甲烷被完全氧化,然后该氧载体能均匀地释放出具有高选择性的体相晶格氧将甲烷氧化为CO和H2。通过对氧载体再生条件的控制,可以有效提高目标产物的选择性,当再生温度为850℃,再生时间为7min时, 获得了最大的CO（96.68%）和H2（97.56%）选择性,同时H2与CO摩尔比达到2.02。在无气相氧存在下,用Ce-Fe-O中晶格氧实现甲烷部分氧化制合成气的方法是可行的。     

铈铁复合氧化物制备及其甲烷选择性氧化制合成气催化性能

用共沉淀法制备了CeO2-Fe2O3氧载体。在固定床反应器中研究了氧载体中晶格氧部分氧化甲烷的反应,并用空气为氧源进行了氧载体还原-氧化再生循环实验,通过XRD,O2-TPD,H2-TPR等手段对氧载体进行了表征。结果表明,CeO2-Fe2O3氧载体中的体相晶格氧适于部分氧化甲烷制合成气。新鲜的氧载体上存在二种氧：有强氧化性的吸附氧（包括弱吸附分子氧和表面晶格氧）和高选择性的体相晶格氧。在高温条件下（800℃）,CeO2-Fe2O3氧载体在消耗掉吸附氧后能均匀地释放出体相晶格氧将甲烷高选择性的氧化为CO和H2。循环实验表明,可以通过循环来提高合成气的选择性,经长时间的循环CeO2-Fe2O3氧载体上有CeFeO3出现,但其并未对选择性造成不利影响。     

开环棉籽糖分子内交联血红蛋白及其戊二醛的二次交联

用高碘酸钠氧化制备开环棉籽糖(O-Raffinose),将其作为交联剂对脱氧态无基质血红蛋白(Stroma-freehemoglobinSFHb)进行修饰.十二烷基磺酸钠-聚丙烯酰胺不连续电泳(SDS-PAGE)结果显示,开环棉籽糖交联血红蛋白(O-Ra-Hb)与SFHb相比抗解聚性有明显提高;琼脂糖(Sepharose)凝胶层析结果显示,SFHb和O-Ra-Hb出峰时间和峰形大小基本相同,说明交联反应主要发生在分子内的亚基间,基本没有分子间交联产物.用戊二醛(GDA)在优化条件下对O-Ra-Hb进行分子间二次交联,SDS-PAGE结果显示,二次交联产物稳定性比O-Ra-Hb有了进一步提高;Sepharose凝胶层析结果表明,产物中分子量为65000的未聚合的O-Ra-Hb组分为22.6%,分子量为130000～600000的组分为76.9%,分子量为600000以上的组分仅为0.5%,达到了预期目的.     

VOSO_4/活性炭上常压催化氧化乳酸乙酯合成丙酮酸乙酯

以氧化改性活性炭为载体,用浸渍法制备了系列VOSO4/活性炭催化剂(VO/ACO).采用FT-IR、XRD、ICP和比表面及孔结构测定等表征了催化剂组成与结构.考察了VO/ACO催化剂在常压分子氧氧化乳酸乙酯中的催化作用.结果表明,氧化活性炭是氧钒催化剂的有效载体,以pH=3的VOSO4溶液浸渍得到的VO-3/ACO催化剂具有优良的催化性能,在二氯乙烷中常压,80℃反应18 h,乳酸乙酯转化完全,丙酮酸乙酯的选择性达95.2%.催化剂重复使用三次后的性能基本保持不变.     

Low‐Fouling Electrosprayed Hemoglobin Nanoparticles with Antioxidant Protection as Promising Oxygen Carriers

Despite all the attempts to create advanced hemoglobin (Hb)‐based oxygen carriers (HBOCs) employing an encapsulation platform, major challenges including attaining a high Hb loading and long circulation times still need to be overcome. Herein, the fabrication, for the first time, of nanoparticles fully made of Hb (Hb‐NPs) employing the electrospray technique is reported. The Hb‐NPs are then coated by antioxidant and self‐polymerized poly(dopamine) (PDA) to minimize the conversion of Hb into nonfunctional methemoglobin (metHb). The PDA shell is further functionalized with poly(ethylene glycol) (PEG) to achieve stealth properties. The results demonstrate that the as‐prepared Hb‐NPs are hemo‐ and biocompatible while offering antioxidant protection and decreasing the formation of metHb. Additionally, decoration with PEG results in decreased protein adsorption onto the Hb‐NPs surface, suggesting a prolonged retention time within the body. Finally, the Hb‐NPs also preserve the reversible oxygen‐binding and releasing properties of Hb. All in all, within this study, a novel HBOCs with high Hb content is fabricated and its potential as an artificial blood substitute is evaluated.     

Capillary electrophoretic analysis of whole blood samples for hemoglobin-based oxygen carriers without the use of immunoprecipitation

Hemoglobin-based oxygen carriers (HBOCs) are blood substitutes, synthesized by polymerizing hemoglobin, which are being developed and investigated as alternatives to blood for medical purposes. However, due to their ability to increase the oxygen carrying capacity when taken by healthy individuals, HBOCs have been used as a doping agent among endurance athletes and are included in the World Anti-Doping Agency's Prohibited List. To maintain the fairness of competitions and continue the battle against doping, it is essential to be able to detect HBOCs if present in an athlete's blood. To achieve this goal, it is necessary to differentiate HBOCs from the native hemoglobin and to do so in a cost and time effective manner. We have developed a rapid capillary zone electrophoresis (CZE), UV absorbance, method capable of detecting HBOCs, in whole blood samples, at levels below those considered necessary to provide a performance enhancement. Our approach to the analysis for HBOCs utilizes the whole blood sample, not just the plasma, and does not require the use of immunoprecipitants to ensure accurate analysis. By lysing the red blood cells and using centrifugal filtration, followed by our CZE separation, we are able to effectively distinguish between native hemoglobin and HBOCs. Through this method, we have been able to reliably detect concentrations of HBOCs at the equivalent of 5.5 g/L, the equivalent to a 3.5% increase in blood hemoglobin concentration for an athlete.     

Regulating the Oxygen Affinity of Single Atom Catalysts by Dual-atom Design for Enhanced Oxygen Reduction Reaction Activity

This work chooses Cu/Fe single-atom catalysts(SACs) with weak/strong oxygen affinity to clarify the effect of dual-atom configuration on oxygen reduction reaction(ORR) performance based on density functional theory(DFT) calculations. The stability and ORR activity of single or dual Cu/Fe atomic sites anchored on nitrogen-doped graphene sheets(Cu-N₄-C, Cu₂-N₆-C, Fe-N₄-C, and Fe₂-N₆-C) are investigated, and the results indicate the dual-atom catalysts(Cu₂-N₆-C and Fe₂-N₆-C) are thermodynamically stable enough to avoid sintering and aggregation. Compared with single-atom active sites of Cu-N₄-C, which show weak oxygen affinity and poor ORR performance with a limiting potential of 0.58 V, the dual-Cu active sites of Cu₂-N₆-C exhibit enhanced ORR activity with a limiting potential up to 0.87 V due to strengthened oxygen affinity. Interestingly, for Fe SACs with strong oxygen affinity, the DFT results show that the dual-Fe sites stabilize the two OH^* ligands structure[Fe₂(OH)₂-N₆-C], which act as the active sites during ORR process, resulting in greatly improved ORR performance with a limiting potential of 0.90 V. This study suggests that the dual-atom design is a potential strategy to improve the ORR performance of SACs, in which the activity of the single atom active sites is limited with weak or strong oxygen affinity.     

Electrophoretic, size-exclusion high-performance liquid chromatography and liquid chromatography-electrospray ionization ion trap mass spectrometric detection of hemoglobin-based oxygen carriers

Hemoglobin-based oxygen carriers (HBOCs) are blood substitutes based on hemoglobin of either bovine or human origin and they can potentially be misused in elite sports to improve endurance performance. Recently, three methods have been proposed in doping control analysis to allow HBOCs screening and identification by application of electrophoresis, size-exclusion chromatography coupled with HPLC and LC coupled with tandem mass spectrometry (LC/MSMS). In view of the Athens 2004 Olympic Games, modifications were introduced in order to increase the specificity of these methods. The sample preparation protocols of the electrophoretic and SEC-HPLC methods were modified with the introduction of sequential ultra filtration steps to remove all heme containing material below 100 kDa, thus leaving only HBOCs material for analysis. Furthermore, a modification of the LC/MSMS methodology was introduced to allow full scan MS-MS spectra of peptide segments arising from the tryptic digestion of bovine HBOCs. These relatively simple methodological modifications have major impact, as far as time and cost effectiveness is concerned in doping control procedures, because they provide a useful tool in order to identify which suspect samples from the initial visual screening are due to hemolysis and exclude them from further analysis.     

Methodologies for detection of hemoglobin-based oxygen carriers

Blood substitutes based on hemoglobin or hemoglobin-based oxygen carriers (HBOCs) are oxygen-carrying therapeutic agents developed for use in operations and emergencies in place of donated blood. Increased oxygen-carrying capacity through the use of blood substitutes could help elite athletes to lengthen endurance capacity and improve their performance. As blood substitutes become more readily available, it is essential that a qualitative detection method for their abuse in sport is available. Ideally, such a method would be simple and inexpensive. This study investigates methods that could be used as screening procedures to easily detect HBOCs in plasma and develops tests that can unequivocally confirm their presence. The investigation into the screening method indicates that the direct visual screening of plasma discoloration is the most appropriate with detection limits of less than 1% HBOC in plasma. Two methods are shown to confirm the presence of exogenous hemoglobin in plasma samples, size-exclusion chromatography with photodiode array detection and high-performance liquid chromatography analysis of enzymatic digests with detection by electrospray mass spectrometry. This work emphasizes the need for cooperation between drug developers and sports testing laboratories to ensure that methods for the detection of putative doping agents are available prior to product release.     

Structure of Oxygen and CO Adsorption on Ru(0001) Electrode

It is important to understand the chemisorption of oxygen and CO on Ru(0001) surface. CO oxidation at oxygen precovered Ru(0001) surface at low oxygen coverages gave an extremely low CO oxidation rate, and it was also observed that, with a nominal oxygen coverage exceeding ca. 3 mL, rather high CO/CO2 conversion probabilities were achieved1. In the case of coadsorption of CO and oxygen on Ru(0001) surface under UHV conditions, a model comprising two CO molecules in an (22)-O unit cel…     

含氟共聚物与钴卟啉复合膜的制备及促进氧输送性能

研究了甲基丙烯酸八氟戊酯-乙烯基咪唑共聚物与钴卟啉复合膜的制备及钴卟啉与氧络合、促进输送性能.共聚物中的咪唑基与钴卟啉的第五配位点在溶液中络合,制得的复合膜具有快速和可逆的氧结合特性.温度降低,钴卟啉与氧络合的平衡常数增加;膜中的钴卟啉与氧络合平衡常数大于N,N-二甲基甲酰胺(DMF)溶液中的平衡常数.钴卟啉与氧络合和选择性地促进氧的输送使共聚物/钴卟啉复合膜的氧渗透系数和氧/氮选择系数提高.     

Oxygen sensitive microwells

Oxygen tension is critical in a number of cell pathways but is often overlooked in cell culture. One reason for this is the difficulty in modulating and assessing oxygen tensions without disturbing the culture conditions. Toward this end, a simple method to generate oxygen-sensitive microwells was developed through embossing polystyrene (PS) and platinum(ii) octaethylporphyrin ketone (PtOEPK) thin films. In addition to monitoring the oxygen tension, microwells were employed in order to isolate uniform clusters of cells in microwells. The depth and width of the microwells can be adapted to different experimental parameters easily by altering the thin film processing or embossing stamp geometries. The thin oxygen sensitive microwell substrate is also compatible with high magnification modalities such as confocal imaging. The incorporation of the oxygen sensor into the microwells produces measurements of the oxygen tension near the cell surface. The oxygen sensitive microwells were calibrated and used to monitor oxygen tensions of Madin-Darby Canine Kidney Cells (MDCKs) cultured at high and low densities as a proof of concept. Wells 500 μm in diameter seeded with an average of 330 cells exhibited an oxygen level of 12.6% whereas wells seeded with an average of 20 cells per well exhibited an oxygen level of 19.5%, a 35.7% difference. This platform represents a new tool for culturing cells in microwells in a format amenable to high magnification imaging while monitoring the oxygen state of the culture media.     

Bifunctional Catalysts for Reversible Oxygen Evolution Reaction and Oxygen Reduction Reaction

Metal-air batteries (MABs) and reversible fuel cells (RFCs) rely on the bifunctional oxygen catalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Finding efficient bifunctional oxygen catalysts is the ultimate goal and it has attracted a great deal of attention. The dilemma is that a good ORR catalyst is not necessarily efficient for OER, and vice versa. Thus, the development of a new type of bifunctional oxygen catalysts should ensure that the catalysts exhibit high activity for both OER and ORR. Composites with multicomponents for active centers supported on highly conductive matrices could be able to meet the challenges and offering new opportunities. In this Review, the evolution of bifunctional catalysts is summarized and discussed aiming to deliver high-performance bifunctional catalysts with low overpotentials.     

Oxygen scavenging enhances exothermic behavior of aluminum-fueled energetic composites

The theoretical heat of combustion for aluminum (Al) and copper oxide (CuO) under ideal conditions is roughly 4,100 kJ kg^?1, but in practice only a fraction of this energy is available for application. Approaching the theoretical value requires innovative strategies for exploiting reaction kinetics. One strategy is to force Al to react CuO as opposed to oxygen from the environment and this approach was shown here to improve the measured heat of combustion significantly. This was achieved through tailoring the mixture using an additive with oxygen affinity prior to Al ignition. The additive is hafnium hydride (HfH₂) and this study examines reaction kinetics for HfH₂ 0–60 mass% concentration range using simultaneous thermal-gravimetric analysis. Results reveal that 0–10 mass% HfH₂ additive enhanced the heat of combustion of Al+CuO by 12 %. The observed enhancement is attributed to HfH₂ creating oxidation competitions that directly influence the combustion performance of Al+CuO. The transition of this equilibrium-based observation to a non-equilibrium fast heating setup is also investigated using plate deformation tests. Exploding bridge wire heads initiated by a capacitive discharge unit are used to dent plates and the deformation energies are estimated to observe the effects of varying composites in a non-equilibrium setting. The presence of HfH₂ showed improved deformation energies for Al+CuO in the 10 % mass HfH₂ range. This work introduces a novel method of using a catalyst in thermite composites to enhance combustive behaviors through oxygen scavenging. Using the same concept as getter materials, the atmosphere is scavenged of free oxygen allowing for the fuel to react exclusively with the solid oxidizer.