Tissue-Specific Ferritin- and GFP-Based Genetic Vectors Visualize Neurons by MRI in the Intact and Post-Ischemic Rat Brain

(1) Background: Neurogenesis is considered to be a potential brain repair mechanism and is enhanced in stroke. It is difficult to reconstruct the neurogenesis process only from the histological sections taken from different animals at different stages of brain damage and restoration. Study of neurogenesis would greatly benefit from development of tissue-specific visualization probes. (2) Purpose: The study aimed to explore if overexpression of ferritin, a nontoxic iron-binding protein, under a doublecortin promoter can be used for non-invasive visualization of neurogenesis using magnetic resonance imaging (MRI). (3) Methods: Ferritin heavy chain (FerrH) was expressed in the adeno-associated viral backbone (AAV) under the doublecortin promoter (pDCX), specific for young neurons, in the viral construct AAV-pDCX-FerrH. Expression of the enhanced green fluorescent protein (eGFP) was used as an expression control (AAV-pDCX-eGFP). The viral vectors or phosphate-buffered saline (PBS) were injected intracerebrally into 18 adult male Sprague–Dawley rats. Three days before injection, rats underwent transient middle-cerebral-artery occlusion or sham operation. Animals were subjected to In vivo MRI study before surgery and on days 7, 14, 21, and 28 days after injection using a Bruker BioSpec 11.7 T scanner. Brain sections obtained on day 28 after injection were immunostained for ferritin, young (DCX) and mature (NeuN) neurons, and activated microglia/macrophages (CD68). Additionally, RT-PCR was performed to confirm ferritin expression. (4) Results: T2* images in post-ischemic brains of animals injected with AAV-pDCX-FerrH showed two distinct zones of MRI signal hypointensity in the ipsilesioned hemisphere starting from 14 days after viral injection—in the ischemic lesion and near the lateral ventricle and subventricular zone (SVZ). In sham-operated animals, only one zone of hypointensity near the lateral ventricle and SVZ was revealed. Immunochemistry showed that ferritin-expressing cells in ischemic lesions were macrophages (88.1%), while ferritin-expressing cells near the lateral ventricle in animals both after ischemia and sham operation were mostly mature (55.7% and 61.8%, respectively) and young (30.6% and 7.1%, respectively) neurons. RT-PCR confirmed upregulated expression of ferritin in the caudoputamen and corpus callosum. Surprisingly, in animals injected with AAV-pDCX-eGFP we similarly observed two zones of hypointensity on T2* images. Cellular studies also showed the presence of mature (81.5%) and young neurons (6.1%) near the lateral ventricle in both postischemic and sham-operated animals, while macrophages in ischemic lesions were ferritin-positive (98.2%). (5) Conclusion: Ferritin overexpression induced by injection of AAV-pDCX-FerrH was detected by MRI using T2*-weighted images, which was confirmed by immunochemistry showing ferritin in young and mature neurons. Expression of eGFP also caused a comparable reduced MR signal intensity in T2*-weighted images. Additional studies are needed to investigate the potential and tissue-specific features of the use of eGFP and ferritin expression in MRI studies.     

Experimentelle und analytische Untersuchung des out‐of‐plane‐Verhaltens von unbewehrten Mauerwerkswänden unter Erdbebenbelastung

Experimental and analytical investigation of the seismic out‐of‐plane behavior of unreinforced masonry walls In addition to the vertical and horizontal load‐bearing in‐plane, masonry must also withstand out‐of‐plane loads that occur in earthquake scenarios. The out‐of‐plane behavior of unreinforced masonry walls depends on a variety of parameters and is very complex due to the strong non‐linearity. Current design methods in German codes and various international codes have not been explicitly developed for out‐of‐plane behavior and contain considerable conservatism. In the present work, shaking‐table experiments with heat‐insulating masonry walls have been conducted to investigate the out‐of‐plane behavior of vertical spanning unreinforced masonry walls. As shown in previous numerical investigations, important parameters are neglected in existing design and analysis models and the out‐of‐plane capacity is underestimated significantly. In the conducted experiments the results of these numerical investigations are verified. Furthermore, the development of an analytical design model to determine the force‐displacement relationship and the out‐of‐plane load‐bearing capacity considering all significant parameters is presented.     

平面桁架构建的定日镜面形支撑结构优化及实验

针对反射面成型的复杂影响因素，提出平面桁架构建的定日镜面形支撑结构优化技术路线. 利用模拟仿真、数值计算和优化算法等方法，解析20 m²定日镜面形定义技术路线的4个组成环节：面形规格及宽高比、上弦杆的截面矩、平面桁架组间距的最优值、机加工中工艺控制要点的量化. 试制小型定日镜进行实验，分析光斑形状和能流密度分布特性，并与理想球面形光斑比较，两者的拟合优度大于0.98. 实验结果表明，当反射镜宽高比取1.2，上弦杆截面矩取40 000 mm⁴，桁架组间距取950 mm，上弦杆和斜杆的开孔公差小于0.9 mm时，反射面形的质量提升. 研究从原理和实践上证明了该优化技术路线的可行性.     

Case history on failure of a 67 M tall reinforced soil slope

Construction of this 67 m high RSS was completed in December 2006. After seven years in-service, a tension crack was observed at the top of the slope. In March 2015 this RSS structure catastrophically collapsed. This RSS structure collapsed in a compound failure mode; as the failure plane passed beneath, partially behind, and partially through the reinforced soil mass. The failure plane beneath the RSS was along a shale-claystone interface. The failure surface partially behind the RSS was along sandstone bedrock with water-seeping bedding planes dipping out of the rock mass. The failure surface through the upper portion of the RSS is where the geogrid reinforcement was overwhelmed by stresses originating from underlying deformation. The RSS collapse occurred after 8.3 years in-service as the shear strength along the shale-claystone interface decreased and approached the fully softened strength. The primary causative factors of this failure are: (i) an insufficient subsurface investigation program and interpretation of data for design and detailing; (ii) insufficient specifications and construction plan details for both foundation preparation and rock backcut benching; (iii) insufficient foundation preparation and rock backcut benching during construction; and (iv) adaptations to the design made during construction.     

煤红外快速热解过程中床层对二次反应的影响

针对煤快速热解研究中样品添加量少(mg级)、焦油收集难等问题，本研究利用压片法制备微薄厚度(mm级)的煤层，并采用红外加热装置考察大添加量(g级)、微薄煤层的快速热解特性。对比堆积煤样和不同煤压片厚度(1.5~3 mm)与个数(1~2)的压片煤样热解特性发现，压片煤层热解过程的二次反应受到明显抑制，焦油产率急剧增加，在1000℃时达9.96%，为格金分析的1.5倍，实现油气产量的同步增长。模拟蒸馏分析发现，堆积状态下焦油以沥青质为主，而微薄煤层制焦油含大量轻油、酚油、萘油、洗油和蒽油。GC-MS和FTIR分析表明，随煤层厚度和个数的减少，焦油组分和含量提高，芳香烃类和含氧官能团吸收增加，进一步验证煤快速热解过程中煤层厚度对焦油产率和品质的影响，揭示在二次反应充分抑制下煤高温热解的初级反应特性。     

基于直剪试验的页岩水化作用的强度弱化规律

随着页岩气资源的不断开发,水平井段的硬脆性页岩井壁失稳问题也越来越突出。为此,通过对水基、油基钻井液浸泡后的页岩岩样直剪试验,并结合单组弱面强度理论,分析了内聚力和内摩擦角对页岩强度的影响规律以及不同钻井液浸泡后的页岩强度弱化规律。对试验数据的分析结果表明:①水基、油基钻井液浸泡后内聚力和内摩擦角均下降,其垂直层理面方向的内摩擦角和内聚力均高于平行层理面方向;②页岩强度随钻井液浸泡时长增加而降低,受水化作用影响层理面导致强度降低,微裂缝表现为更易扩展,页岩容易产生破坏;③内聚力控制页岩强度大小,内摩擦角控制页岩沿弱面破坏的范围;④水基钻井液对页岩影响较为明显,页岩受其浸泡后强度下降较快,并随浸泡时间增加页岩强度持续下降,同时沿弱面破坏的角度限明显增大,油基钻井液能较好地保持岩样强度水平。最后,以四川盆地志留系龙马溪组M气藏为例,通过水平井段坍塌压力的计算,认识到水基钻井液基本不能满足钻井要求,而应采用油基钻井液且优先考虑沿最小水平地应力方向钻进。     

The effect of maturity and tissue on the ability of mid infrared spectroscopy to predict the geographical origin of banana (Musa Cavendish)

The objective of this study was to evaluate the effect of sample presentation (tissue type) and maturity (ripe and unripe) on the classification of banana (Musa Cavendish) samples sourced from two different geographical regions and analysed using mid infrared (MIR) spectroscopy. The coefficient of determination (R²) and the standard error of cross-validation (SECV) obtained using partial least squares discriminant analysis were 0.83 (0.33), 0.75 (0.25) and 0.94 (0.19) for the prediction of maturity, geographical origin and tissue type, respectively. No effect of either of type of tissue (e.g. pulp or peel) or maturity was observed. The results of this study demonstrated that MIR spectroscopy might be used to classify the origin of the banana samples at different degrees of ripeness. However, one of the limitations of this study is on the number of samples analysed and further validation must be recommended using samples from other sources, regions and harvest seasons.     

The effect of the exposed crystal plane on the antioxidant activity of nanoceria

Previous reports have noted that exposed crystal planes could affect the antioxidant activity of nanocerias, although the synthesized nanocerias used in those studies had different exposed crystal planes, as well as different sizes and morphologies. In order to better understand the effect of the crystal planes on the antioxidant activity of the materials, two types of nanocerias with similar morphology and size distribution but different crystal planes were synthesized using the hydrothermal method (CeO₂–H) and the ultrasonic template method (CeO₂–U). The antioxidant activities of the nanocerias were further explored within different ·OH concentrations in the reaction system. The experimental results showed that there is an obvious difference in the antioxidant activity of the two types of nanocerias in the lower free radical concentration system due to the effects of exposed crystal planes. CeO₂–U, with more active crystal planes (100), had stronger antioxidant activity. However, with the increase in the ·OH concentration in the reaction system, the difference in the antioxidant activity of the two nanocerias decreased. This research will increase our understanding of the antioxidant activity of the exposed crystal planes on nanocerias.     

面源红外诱饵对抗红外制导导弹干扰策略研究

面源红外诱饵使用的过程中,合理有效的干扰策略是干扰红外制导导弹的关键,针对这一问题,通过理论分析与仿真模拟相结合得到面源红外诱饵对抗红外制导导弹的干扰策略。首先以红外成像制导导弹为例,介绍红外制导导弹的仿真模型,然后将攻击过程分为锁定前与锁定后,以命中率为评价指标,得到两个阶段下的最佳干扰策略,包括诱饵的最佳释放时机、释放间隔以及载机应采取的机动动作等。     

Diffuse reflectance behavior of the printed cotton/nylon blend fabrics treated with zirconium and cerium dioxide and citric acid in near- and short-wave IR radiation spectral ranges

Near- and short-wave IR emission spectra of printed cotton/nylon blend fabrics coated with inorganic compounds in order to tune their diffuse reflectance behavior to the ones with woodland and desert backgrounds are investigated. In this regard, cotton/nylon blend fabrics printed with a four-color digital pattern were used as the substrate, and different concentrations of zirconium and cerium dioxide (ZrO₂ and CeO₂) with and without citric acid as a cross-linker were loaded on these fabrics using the pad-dry-cure method. The diffuse reflectance of the coated fabrics with various concentrations of nanoparticles and a cross-linker was first measured by near-infrared (NIR) diffuse reflectance spectroscopy (DRS). Then, fabrics with an optimum concentration of nanoparticles and appropriate reflectivity profiles similar to woodland and desert were investigated by field emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), washing, and rubbing fastness properties. In general, NIR and short-wave infrared (SWIR) reflectance of fabrics coated with ZrO₂ and CeO₂ nanoparticles in range of 1% to 1.5% (w/v [%]) was suitable for matching with different environments. According to the findings obtained from the durability test, it was concluded that the washing fastness of the treated fabrics with CeO₂ nanoparticles was excellent in both environments. FE-SEM images of the treated fabrics containing ZrO₂ and CeO₂ indicated that the presence of nanoparticles on the surface of fabrics in woodland patterns was greater than the desert ones. However, the coated fabrics with CeO₂ and citric acid in the woodland pattern have shown better dispersion with a mean particle size of 30 to 60 nm.