Viscosity reduction of isotonic solutions of the photosensitizer TPCS2a by cyclodextrin complexation

Meso-tetraphenyl chlorin disulphonate (TPCS_2a) is a photosensitizer (PS) particularly developed and patented for use in the technology of photochemical internalization (PCI) against cancer. TPCS_2a is known to aggregate in aqueous media even at low concentrations (≥0.1?µM) and to form a high-viscosity network at clinically relevant concentrations (mM). The aim of this work was to evaluate the effect of two hydroxypropylated cyclodextrin derivatives of beta and gamma type, respectively i.e. HPβCD and HPγCD, on the aggregation and solubilization of TPCS_2a in isotonic solutions. Samples containing micromolar concentrations of TPCS_2a were studied spectrophotometrically, while samples containing a clinical relevant concentration (10?mM?=?9?mg/ml) of TPCS_2a were evaluated by dynamic viscosity measurements. HPβCD was determined to be a more suitable solubilizer of TPCS_2a than HPγCD in aqueous media both in the absence and presence of salt. The complexation stoichiometry between TPCS_2a/HPβCD at micromolar to millimolar concentrations of TPCS_2a was determined to be 1:3 and 1:2 in the absence and presence of isotonic NaCl, respectively. The network of TPCS_2a (10?mM) was broken down in the presence of 3% w/v (=?20?mM) HPβCD, i.e. a 1:2 molar ratio between TPCS_2a and the cyclodextrin. Formation of the inclusion complex resulted in low viscosity samples both in water and in the presence of isotonic NaCl or phosphate buffered saline (PBS) at 25?°C and 37?°C.     

基于强化学习的HP模型优化方法研究

蛋白质结构预测问题一直是生物信息学中的重要问题。基于疏水极性模型的蛋白质二维结构预测问题是一个典型的NP难问题。目前疏水极性模型优化的方法有贪心算法、粒子群算法、遗传算法、蚁群算法和蒙特卡罗模拟方法等，但这些方法成功收敛的鲁棒性不高，容易陷入局部最优。由此提出一种基于强化学习的HP模型优化方法，利用其连续马尔可夫最优决策与最大化全局累计回报的特点，在全状态空间中，构建基于能量函数的奖赏函数，引入刚性重叠检测规则，充分挖掘生物序列中的全局进化关系，从而进行有效与稳定的预测。以3条经典论文序列和5条Uniref50序列为实验对象，与贪心算法和粒子群算法分别进行了鲁棒性、收敛性与运行时间的比较。贪心算法只能在62.5%的序列上进行收敛，该文方法能在5万次训练后稳定的在所有序列上达到了收敛。与粒子群算法相比，两者都能找到最低能量结构，但该文的运行时间较粒子群算法降低了63.9%。     

Lower temperature hydrothermal pretreatment improves the anaerobic digestion performance of spent cow bedding

The anaerobic digestion (AD) performance of spent cow bedding was investigated with different hydrothermal pretreatment (HP) conditions. Spent cow bedding was pretreated with low temperatures (50, 70, and 90℃) and different pretreatment times (2-72 h) with ammonia and without ammonia. The results showed that spent cow bedding was a good raw material for AD. After pretreatment, the concentration of volatile fatty acids (VFAs) in the group of hydrothermal pretreatments with ammonia (HPA) was higher than that in the HP group at the same pretreatment temperature and time. The optimal pretreatment condition was achieved with an HPA of 50℃ holding for 72 h. At the optimal condition, the highest concentration of VFAs was 1.58-10.85 times higher than that of the other pretreated groups. The highest hemicellulose and lignin removal rates were 58.07% and 10.32%, respectively. The highest methane yield was 163.0 ml·(g VS)^-1, which was 48.9% higher than that of the untreated group. The VFAs, pH, and reducing sugars showed positive relationships with the methane yield. Therefore, HP at low temperature can enhance the AD performance of spent cow bedding.     

HP700型圆锥破碎机在调军台选厂的初步实践

ＨＰ７００型圆锥破碎机具有优良的性能，增大了偏心距，加快了轴转速，采用曲线型（非阻塞型）破碎腔，从而在破碎腔内只需较低破碎力，在调军台选厂的初步实践达到了较好的效果。     

HP800破碎机常见故障原因分析及对策

HP800破碎机是鞍矿齐大山选矿厂破碎系统中的主体设备,具有破碎比大、运转效率高及产品粒度均匀等优点,它能否稳定运行对选厂的生产起着至关重要的作用.因此,对该破碎机常见故障产生的原因进行分析与处理,确保设备稳定运行.     

Exposure and effects assessment of persistent organohalogen contaminants in arctic wildlife and fish

Persistent organic pollutants (POPs) encompass an array of anthropogenic organic and elemental substances and their degradation and metabolic byproducts that have been found in the tissues of exposed animals, especially POPs categorized as organohalogen contaminants (OHCs). OHCs have been of concern in the circumpolar arctic for decades. For example, as a consequence of bioaccumulation and in some cases biomagnification of legacy (e.g., chlorinated PCBs, DDTs and CHLs) and emerging (e.g., brominated flame retardants (BFRs) and in particular polybrominated diphenyl ethers (PBDEs) and perfluorinated compounds (PFCs) including perfluorooctane sulfonate (PFOS) and perfluorooctanic acid (PFOA) found in Arctic biota and humans. Of high concern are the potential biological effects of these contaminants in exposed Arctic wildlife and fish. As concluded in the last review in 2004 for the Arctic Monitoring and Assessment Program (AMAP) on the effects of POPs in Arctic wildlife, prior to 1997, biological effects data were minimal and insufficient at any level of biological organization. The present review summarizes recent studies on biological effects in relation to OHC exposure, and attempts to assess known tissue/body compartment concentration data in the context of possible threshold levels of effects to evaluate the risks. This review concentrates mainly on post-2002, new OHC effects data in Arctic wildlife and fish, and is largely based on recently available effects data for populations of several top trophic level species, including seabirds (e.g., glaucous gull (Larus hyperboreus)), polar bears (Ursus maritimus), polar (Arctic) fox (Vulpes lagopus), and Arctic charr (Salvelinus alpinus), as well as semi-captive studies on sled dogs (Canis familiaris). Regardless, there remains a dearth of data on true contaminant exposure, cause-effect relationships with respect to these contaminant exposures in Arctic wildlife and fish. Indications of exposure effects are largely based on correlations between biomarker endpoints (e.g., biochemical processes related to the immune and endocrine system, pathological changes in tissues and reproduction and development) and tissue residue levels of OHCs (e.g., PCBs, DDTs, CHLs, PBDEs and in a few cases perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonates (PFSAs)). Some exceptions include semi-field studies on comparative contaminant effects of control and exposed cohorts of captive Greenland sled dogs, and performance studies mimicking environmentally relevant PCB concentrations in Arctic charr. Recent tissue concentrations in several arctic marine mammal species and populations exceed a general threshold level of concern of 1 part-per-million (ppm), but a clear evidence of a POP/OHC-related stress in these populations remains to be confirmed. There remains minimal evidence that OHCs are having widespread effects on the health of Arctic organisms, with the possible exception of East Greenland and Svalbard polar bears and Svalbard glaucous gulls. However, the true (if any real) effects of POPs in Arctic wildlife have to be put into the context of other environmental, ecological and physiological stressors (both anthropogenic and natural) that render an overall complex picture. For instance, seasonal changes in food intake and corresponding cycles of fattening and emaciation seen in Arctic animals can modify contaminant tissue distribution and toxicokinetics (contaminant deposition, metabolism and depuration). Also, other factors, including impact of climate change (seasonal ice and temperature changes, and connection to food web changes, nutrition, etc. in exposed biota), disease, species invasion and the connection to disease resistance will impact toxicant exposure. Overall, further research and better understanding of POP/OHC impact on animal performance in Arctic biota are recommended. Regardless, it could be argued that Arctic wildlife and fish at the highest potential risk of POP/OHC exposure and mediated effects are East Greenland, Svalbard and (West and South) Hudson Bay polar bears, Alaskan and Northern Norway killer whales, several species of gulls and other seabirds from the Svalbard area, Northern Norway, East Greenland, the Kara Sea and/or the Canadian central high Arctic, East Greenland ringed seal and a few populations of Arctic charr and Greenland shark.     

1000 MW二次再热机组高压加热器系统开发及应用

介绍了由上海电气电站设备有限公司电站辅机厂自主开发的1 000 MW二次再热机组的高压加热器系统。其设计开发基于失效模式的设计理念,利用有限元分析和温度场分析方法,在典型三段式换热结构的基础上创新性地开发了纯逆流换热结构,选取特殊的耐热钢91材料,制定了专有的企业标准和设计准则。该设备和系统具有安装维护便捷、运行平稳高效的特点,很好的符合了机组运行的边界条件,提高了机组的效率。该技术可推广应用到660 MW或1 000 MW同类机组中,将取得极大的经济效益和社会效益。     

液化天然气高压泵泵井液位波动的原因分析及措施简

通过对上海液化天然气接收站高压泵采井液位大幅波动的原因进行分析,指出泵井内介质LNG物性发生变化是高压泵泵井液位大幅波动的重要原囚之一,并提出了相应的改进和防范措施。     

Power characteristics of a new kind of air‐powered vehicle

Nowadays, hydropneumatic transformer (short for HP transformer) is widely used as the main part of the power system of air‐powered vehicles to pump pressurized hydraulic oil from compressed air with a lower pressure. In this paper, the power system of a new kind of air‐powered vehicle is built using HP transformer as the pneumatic pressure boosting structure and hydraulic motor as the power unit. To set a foundation for the optimization of the power system, the dynamic characteristics are analyzed by building the mathematic model and setting up the experimental station. What is more, the affection of several key structure parameters is researched. Through experimental and simulation study, it can be concluded that, firstly, the mathematical model is proved to be effective; secondly, increasing the area ratio of the pistons would improve the output power as well as reduce the system efficiency, and we choose 6 for a balanced choice; thirdly, the output power and the system efficiency will rise with a larger oil discharge orifice; lastly, the increasing pressure of the input air will raise the power and meanwhile decrease the efficiency. In this system, the efficiency will remain above 30%. This research can be referred to in the design of the power system of air‐powered vehicle and the study on the optimization of the dynamic characteristics. Copyright © 2016 John Wiley & Sons, Ltd.