Relative Contribution of Different Mitochondrial Oxidative Phosphorylation Components to the Retinal Pigment Epithelium Barrier Function: Implications for RPE-Related Retinal Diseases

Disruption of retinal pigment epithelial (RPE) barrier integrity is involved in the pathology of several blinding retinal diseases including age-related macular degeneration (AMD) and diabetic retinopathy (DR), but the underlying causes and pathophysiology are not completely well-defined. Mitochondria dysfunction has often been considered as a potential candidate implicated in such a process. In this study, we aimed to dissect the role of different mitochondrial components; specifically, those of oxidative phosphorylation (OxPhos), in maintaining the barrier functionality of RPE. Electric cell-substrate impedance sensing (ECIS) technology was used to collect multi-frequency electrical impedance data to assess in real-time the barrier formation of the RPE cells. For this purpose, the human retinal pigment epithelial cell line—ARPE-19—was used and treated with varying concentrations of specific mitochondrial inhibitors that target different steps in OxPhos: Rotenone for complex I (the largest protein complex in the electron transport chain (ETC)); oligomycin for ATP synthase; and carbonyl cyanide-p-trifluoromethoxyphenyl hydrazone (FCCP) for uncoupling ATP synthesis from the accompanying ETC. Furthermore, data were modeled using the ECIS-Zθ software to investigate in depth the effects of these inhibitors on three separate barrier parameters: cell–cell interactions (R_b), cell–matrix interactions (α), and the cell membrane capacitance (C_m). The viability of ARPE-19 cells was determined by lactate dehydrogenase (LDH) Cytotoxicity Assay. The ECIS program’s modeling demonstrated that FCCP and thus OxPhos uncoupling disrupt the barrier function in the ARPE-19 cells across all three components of the total resistance (Rb, α, and C_m) in a dose-dependent manner. On the other hand, oligomycin and thus ATP synthase inhibition mostly affects the ARPE-19 cells’ attachment to their substrate evident by a significant decrease in α resistance in a dose-dependent manner, both at the end and throughout the duration of the experiment. On the contrary, rotenone and complex I inhibition mostly affect the ARPE-19 paracellular resistance R_b in a dose-dependent manner compared to basolateral resistance α or C_m. Our results clearly demonstrate differential roles for different mitochondrial components in maintaining RPE cell functionality in which uncoupling of OxPhos is a major contributing factor to the disruption barrier function. Such differences can be used in investigating gene expression as well as for screening of selective agents that improve the OxPhos coupling efficiency to be used in the therapeutic approach for treating RPE-related retinal diseases.     

Explosive Strength and Impact Sensitivity of Several PBXs Based on Attractive Cyclic Nitramines

Plastic explosives based on different cyclic nitramines with different polymeric matrices were prepared and studied. The used polymeric matrices were fabricated on the basis of polyisobutylene (PIB), acrylonitrile‐butadiene rubber (ABR), Viton A, and polydimethyl‐siloxane as binders, whereas the nitramines named RDX (1,3,5‐trinitroperhydro‐1,3,5‐triazine), β‐HMX (β‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine), BCHMX (cis‐1,3,4,6‐tetranitrooctahydroimidazo‐[4,5‐d]imidazole) and ε‐HNIW (ε‐2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane) were used as explosive fillers. Commercial Semtex 10, based on pentaerythritol tetranitrate (PETN), was used for comparison. Impact sensitivity, loading density, ρ, detonation velocity, D, and relative explosive strength (RS) measured by ballistic mortar were determined. It was concluded that plastic BCHMX based on Viton A or PIB‐matrix exhibits higher RS compared with PBXs based on RDX and HMX. Correlations between RS and the impact sensitivity, the ρD² term and the square of the detonation velocity were studied and discussed. The results confirm the well‐known fact that increasing the performance is usually accompanied by an increase in the sensitivity of the explosives. In this connection, Viton A enables achieving a high RS, but with a relatively high sensitivity of the PBXs, whereas the polydimethyl‐siloxane matrix should perhaps give PBXs with optimum explosive strength and sensitivity parameters.     

Mitochondrial bioelectrocatalysis for biofuel cell applications

Mitochondria modified electrodes have been developed and characterized that utilize whole mitochondria isolated from tubers and immobilized within a quaternary ammonium modified Nafion membrane on a carbon electrode that can oxidize pyruvate and fatty acids. Detailed characterization of the performance of these mitochondria modified electrodes has been accomplished by coupling the mitochondria-based bioanode with a commercial air breathing cathode in a complete pyruvate/air biofuel cell. The studies included the effect of fuel (pyruvate) concentration, mitochondria lysing, temperature and pH on the performance of the mitochondria catalyzed, pyruvate/air biofuel cell. Effect of oxygen and cytochrome c oxidase inhibitors on biofuel cell performance has allowed us to further understand the mechanism of electron transfer with the carbon electrode.     

Degradation of TNT,RDX, and HMX Explosive Wastewaters Using Zero‐Valent Iron Nanoparticles

The high‐energy explosives 2,4,6‐trinitrotoluene (TNT), hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX), and the high melting explosive octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) are common groundwater contaminants at active and abandoned munitions production facilities causing serious environmental problems. A highly efficient and environmentally friendly method was developed for the treatment of the explosives‐contaminated wastewaters using zero‐valent iron nanoparticles (ZVINs). ZVINs with diameters of 20–50 nm and specific surface areas of 42.56 m² g⁻¹ were synthesized by the co‐precipitation method. The explosives degradation reaction is expressed to be of pseudo first‐order and the kinetic reaction parameters are calculated based on different initial concentrations of TNT, RDX, and HMX. In addition, by comparison of the field emission scanning electron microscopy (FE‐SEM) images for the fresh and reacted ZVINs, it was apparent that the ZVINs were oxidized and aggregated to form Fe₃O₄ nanoparticles as a result of the chemical reaction. The X‐ray diffraction (XRD) and X‐ray absorption near edge structure (XANES) measurements confirmed that the ZVINs corrosion primarily occurred due to the formation of Fe₃O₄. Furthermore, the postulated reaction kinetics in different concentrations of TNT, RDX, and HMX, showed that the rate of TNT removal was higher than RDX and HMX. Furthermore, by‐products obtained after degradation of TNT (long‐chain alkanes/methylamine) and RDX/HMX (formaldehyde/methanol/hydrazine/dimethyl hydrazine) were determined by LC/MS/MS, respectively. The high reaction rate and significant removal efficiencies suggest that ZVINs might be suitable and powerful materials for an in‐situ degradation of explosive polluted wastewaters.     

A Pressurized Vessel Test to Measure the Minimum Burning Pressure of Water‐Based Explosives

It is well known that water‐based commercial explosives locally ignited in closed vessels do not undergo self‐sustained combustion when the pressure is lower than some threshold value. The latter is usually referred to as the Minimum Burning Pressure (MBP) of the explosive and is now being used by some manufacturers as a basis of safety for many associated manufacture, transport, and handling processes. In the present work, both an apparatus based on hot‐wire ignition and an associated methodology were developed to measure the MBP of water‐based explosives. Typical results for various emulsion and water‐gel explosives are also reported and discussed. It is also shown that the technique could be used to characterize very insensitive explosive substances normally used as explosive precursors.     

Control of metabolism in brown adipose tissue

Cells and mitochondria were isolated from brown adipose tissue of the adult hamster. Isolated mitochondria did not show respiratory control. Reversed electron transport was demonstrated and the oxidation rates of various substrates were compared. α-Glycerophosphate gave the highest oxidative rate with isolated mitochondria. The low basal respiration of isolated brown fat cells could be stimulated by catecholamines, oleate, succinate,a-glycerol phosphate and uncoupling agents. Only norepinephrine or oleate induced respiration was sensitive to inhibition by oligomycin, but this inhibition could not be released by uncoupling agents. Neither atractyloside nor (+) decanoylcarnitine were found to affect respiration, suggesting that mitochondrial nucleotide exchange is slow and that fatty acid oxidation might be carnitine independent. In resting brown fat cells, ATP amounts to 75% of the total adenine nucleotides. NE or oleate caused a small decrease of ATP and a corresponding increase of ADP. Oligomycin caused a partial depletion of ATP content, but subsequent NE addition increased ATP back to control values. This effect was abolished by arsenite. Similarly, uncoupling agents diminished the ATP level which was increased only slightly by NE. Arsenite alone decreased ATP levels to a small extent but a rapid depletion occurred upon subsequent NE addition while respiration was inhibited. Thus, substrate level phosphorylation may be the major energy producing reaction for the generation of ATP and GTP for the activation of fatty acids. Norepinephrine addition to brown fat cells caused an oxidation of pyridine nucleotides, a reduction of flavoproteins and an oxidation of cytochrome b. In constras, succinate produced a reduction of all the components of the respiratory chain. The bioenergetic basis of thermogenesis in brown fat is its high respiratory rate. The rapid respiration induced by norepinephrine or fatty acids appears to be characterized by a low yeild of ATP from oxidative phosphorylation and may be controlled by fatty acid mediated release of energy coupling, possibly by an indirect mechanism. One of nine papers to be published from the Symposium “Brown Adipose Tissue,” presented at the AOCS-AACC Joint Meeting, Washington, D. C., March 1968. This work was done during the tenure of an Established Investigatorship from the American Heart Association.     

Attractive Nitramines and Related PBXs

At present, cis‐1,3,4,6‐tetranitro‐octahydroimidazo‐[4,5‐d]imidazole (bicyclo‐HMX, BCHMX) and ε‐2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane (ε‐HNIW, CL‐20) are a topic of interest from the attractive and the potentially attainable nitramines. They were chosen to be studied in comparison with 1,3,5‐trinitro‐1,3,5‐triazinane (RDX) and β‐1,3,5,7‐tetranitro‐1,3,5‐tetrazocane (β‐HMX). Marginal attention is devoted also to 4,8,10,12‐tetranitro‐2,6‐dioxa‐tetraazawurtzitane (Aurora 5). BCHMX, ε‐HNIW, RDX, and HMX were studied as plastic bonded explosives (PBXs) with elastic properties based on Composition C4 and Semtex 10 matrices. Also they were studied as a highly pressed PBXs based on the Viton A binder. The detonation parameters and sensitivity aspects of these nitramines and their corresponding PBXs were determined. Relative explosive strengths (RS) of these compositions are mentioned with mutual relationships between the measured RS values and some detonation parameters. These relationships indicate a possibility of changes in detonation chemistry of these mixtures filled mainly by HNIW. A sensitivity of RS‐CL20 (HNIW with reduced sensitivity) is reported and the new findings in the friction sensitivity are discussed.     

荧光共轭聚合物在炸药探测中的应用

概述了炸药和炸药探测技术的种类以及荧光共轭聚合物的化学传感原理,综述了荧光共轭聚合物传感技术在炸药探测方面的应用研究进展以及取得的主要成就,并对其存在的主要问题做了简要的说明。提出高灵敏度、高信息负载度、低误判率的专用彩色聚合物炸药探测器件,在未来器件中有着更大的发展前景。     

高聚物溶液在固体炸药表面上的湿润性

通过测试接触角，从湿润热力学和动力学2方面研究了丙烯腈苯乙烯共聚物(AS)溶液在不同粒径的三氨基三硝基苯(TATB)炸药表面湿润性，并结合紫外光谱法探讨了湿润性与吸附量之间的关系。研究结果表明，随着聚合物溶液浓度的增加，AS溶液在TATB表面上的湿润性变差．湿润速度减小。溶剂种类和该炸药粒径不同，其湿润性也不同；若聚合物溶液在固体炸药表面湿润性好．则其在炸药表面上的吸附量大。     

乳化剂对乳化炸药爆炸性能影响的研究

为了探究乳化剂对乳化炸药爆炸性能的影响,分别选取了三种不同的乳化剂制备乳化炸药,采用测时仪法和铅柱压缩法测试了各乳化炸药的爆速和猛度,结果发现,不同乳化剂制备的乳化炸药爆炸性能存在差异。单一的乳化剂不能达到最好的乳化效果,复合乳化剂能改善这一情况,一定程度上提高乳化炸药的爆炸性能。     

Organelle-based biofuel cells: Immobilized mitochondria on carbon paper electrodes

This paper details the development of a mitochondria-based biofuel cell. We show that mitochondria can be immobilized at a carbon electrode surface and remain intact and viable. The electrode-bound mitochondria drive complete oxidation of pyruvate as shown by Carbon-13 NMR and serve as the anode of the biofuel cell where they convert the chemical energy in a biofuel (such as pyruvate) into electrical energy. These are the first organelle-based fuel cells. Researchers have previously used isolated enzymes and complete microbes for fuel cells, but this is the first evidence that organelles can support fuel cell-based energy conversion. These biofuel cells provide power densities of 0.203 ± 0.014 mW/cm², which is in between the latest immobilized enzyme-based biofuel cells and microbial biofuel cells, while providing the efficiency of microbial biofuel cells.     

Thermal Initiation of Non‐Electric Detonators

Cookoff – the concept of heating explosives to ignition – is a useful tool for determining issues that may be related to safely using and storing explosives, and as such, cookoff experiments have been performed on many different materials. All explosive systems require a means of initiation, which is usually a detonator: a device that often contains a sensitive, primary explosive and a more powerful, secondary explosive. Even if the cookoff behaviors of all the individual explosives in an explosive system are known, the behavior of the combined system may be quite different. In this experiment, the cookoff behavior of non‐electric detonators is investigated. It was determined that there was no distinguishable difference between initiating detonators properly or heating them at a rate greater than 10 °C min⁻¹. Heating detonators at rates less than 10 °C min⁻¹ diminished their output.     

PPV Nanotube Sensor Arrays for Explosives Identification by Excitation Wavelength Regulation

The development of sensitive materials for standard and improvised explosives is greatly significant to homeland security. In this paper, the phosphotungstate (NaPT) doped polyphenylene vinylene (PPV) nanotube arrays (NTAs), with excellent optical response, chemical stability, and larger specific surface area, are successfully fabricated by means of the “precursor film” infiltration method. The efficient charge carriers' separation of PPV NTAs can be achieved by doping NaPT to realize the photoelectric detection of explosive vapors. In addition, the identification of six explosives, including ammonium nitrate (AN), dinitrotoluence (DNT), picric acid (PA), p-nitrotoluene (PNT), triacetone triperoxide (TATP), and trinitrotoluene (TNT), can also be realized through the fingerprint atlas. Moreover, the adsorption energy and excited oscillator intensity has also been employed to explain the interaction between NaPT doped PPV nanotube arrays and various explosive molecules. Obviously, the NaPT doped PPV developed has the potential to be used as an explosive sensor.     

国外二硝基茴香醚基炸药发展现状

为及时了解国外二硝基茴香醚(DNAN)炸药技术的发展现状,在系统跟踪国外技术文献和研发动态的基础上,综述了DNAN基炸药的配方设计、制备工艺、环境健康评估和装备应用等最新研究与进展。从中分析得出:美国DNAN基炸药技术发展最迅速,DNAN基炸药配方研究活跃,有多种配方已达到实用化水平;DNAN基熔铸炸药的环保和安全特性明显优于TNT,预示着其在不敏感弹药中具有广泛的应用前景;美军率先大规模装备IMX-101和IMX-104炸药并部署部队,标志着大口径炮弹炸药主装药的不敏感化换装已进入实施阶段;对DNAN的研究提出了建议,应重点发展DNAN基高性能熔铸炸药配方、先进制备工艺技术及应用技术。     

纳米Al对RDX基炸药机械感度和火焰感度的影响

采用机械混合法制备了含纳米Al的RDX基混合炸药,测试了其机械感度和火焰感度,用扫描电镜表征了纳米Al及其炸药的表面形貌,分析了感度变化的原因。结果表明,加入纳米Al后,RDX基炸药的撞击感度、摩擦感度和火焰感度增大;随着纳米Al含量的增加,撞击感度、摩擦感度和火焰感度明显增大;且含纳米Al炸药的撞击感度、摩擦感度和火焰感度均高于含微米Al炸药。纳米Al及含纳米Al炸药均存在微量团聚现象,在一定程度上影响了含纳米Al的RDX基炸药的感度。     

Explosive Mixture for Explosive Welding of Thin Foils

An explosive mixture of PETN and baking soda has been investigated. It was found that the size of the PETN particles had crucial influence on the detonation properties of these explosives. The suggested mix of explosives can be recommended for use in explosive welding.     

理想混合炸药模型的提出及其应用

通过建立“理想混合炸药”模型 ,发现理想混合炸药的爆速 Did与纯组分炸药的爆速 Di和质量分数 Wi之间存在着定量关系 ,据此发展了一种计算混合炸药爆速的新方法。对大量混合炸药的计算结果表明 ,爆速计算值与实验值的一致性令人满意 ,平均误差 1.37%。本文方法的提出 ,不仅提供了一种预测混合炸药爆速的方法 ,而且对高爆速混合炸药的研究具有一定的指导意义     

用C80量热仪研究重铵油炸药的热分解特性

借助C80微量量热仪研究了多孔粒状铵油炸药、3种常用的重铵油炸药（乳化炸药/多孔粒状铵油炸药质量百分比分别为25/75、50/50、75/25）、乳化炸药的热分解特性,以升温速率0.2 K·min^-1时的C80热流速曲线数据为基础,求解了5种炸药试样热分解反应的反应热（ΔH）、表观活化能（E_a）、指前因子（lnA）等热力学和动力学参数。结果表明：乳化炸药的存在抑制了多孔粒状铵油炸药的热分解反应,使其开始发生热分解反应的温度被明显提高。重铵油炸药的表观活化能和放热反应开始温度均高于多孔粒状铵油炸药和乳化炸药,由此得出重铵油炸药的热稳定性高于多孔粒状铵油炸药和乳化炸药的热稳定性。     

低强度冲击下炸药点火的数值模拟

为了研究炸药在低强度冲击下的反应特性,根据标准的Steven试验建立了数值计算模型,采用热力耦合模型和Arrhenius方程描述炸药的热反应,对不同速度弹头撞击炸药过程进行了数值模拟计算,获得了炸药点火的弹头阈值速度,分析了弹头形状对炸药反应的影响。计算结果表明,在弹头阈值速度下,炸药点火存在一定的延迟时间,随着弹头速度的增大,延迟时间缩短;弹头形状会影响炸药受力过程,使炸药点火特性发生变化。     

Comparison of underwater shock wave attenuation of a new insensitive high explosive with different explosives

A series of experiments is performed to compare underwater shock wave attenuation of a new insensitive and aluminized high explosive RS with TNT, JH14, and PBXN-111 explosives. A new model with a uniform expression is proposed to characterize the pressure-time histories of the explosives. Numerical results show that the new model is applicable for both aluminized explosives and ideal explosives. The correlation coefficients for fitted curves are verified by thousands of test data for different explosives, and the accuracy is above 0.99. The energy of the underwater shock wave generated by PBXN-111 and TNT characterized by the new model agrees well with available experimental results. In addition, the shock energy of the new insensitive and aluminized high explosive RS is higher than that of PBXN-11 by 13.4%. The general performance of underwater shock wave attenuation of the insensitive and aluminized high explosive RS is found to be better than that of TNT, JH14, and PBXN-111 explosives.