Evaluating the accuracy of ESR dose determination of pseudo-Early Pleistocene fossil tooth enamel samples using dose recovery tests

In ESR dating of Early Pleistocene fossil tooth enamel samples, the fitting function used for the evaluation of the D_E value is undoubtedly among the major sources of uncertainty. Dose recovery tests performed on fossil tooth enamel showing D_E values >1,000 Gy demonstrate: (i) that high precision ESR measurements (<0.5%) and high D_E reproducibility (<5%) may be achieved; (ii) the appropriateness of the Double Saturating Exponential (DSE) fitting function for ESR dose reconstruction. In contrast, the SSE function, which has been almost exclusively used so far, does simply not correctly describe the behavior of the radiation induced ESR signal of tooth enamel with the dose.Several fitting functions and data weighting options were tested and the combination of a DSE with data weighted by the inverse of the squared intensities is the procedure providing the most accurate D_E results. However, the SSE may nevertheless sometimes produce consistent results if D_max does not exceed 6*D_E. Further work is required in that direction in order to determine more precisely in which conditions the SSE could be used as a fair approximation of the DSE function for these samples.     

一种能区分水印或内容篡改的脆弱水印算法

针对目前脆弱水印算法大多无法区分水印被篡改还是内容被篡改的问题,本文基于多重水印技术提出了一种能区分水印或内容篡改的脆弱水印算法.该算法由子块的主要DCT系数生成恢复水印,将其嵌入到偏移子块的次低位;待恢复水印嵌入后,将恢复水印作为子块内容的一部分生成认证水印,将其嵌入到子块的最低位.理论分析和实验结果表明:本文算法在抵抗量化攻击的同时,不仅能准确定位图像内容被篡改的位置,而且能区分是水印被篡改还是图像内容被篡改,并且在一定条件下可以对内容被篡改的区域进行恢复.     

Application of Natural Clinoptilolite for Ammonium Removal from Sludge Water

Sludge water (SW) arising from the dewatering of anaerobic digested sludge causes high back loads of ammonium, leading to high stress (inhibition of the activity of microorganisms by an oversupply of nitrogen compounds (substrate inhibition)) for wastewater treatment plants (WWTP). On the other hand, ammonium is a valuable resource to substitute ammonia from the energy intensive Haber-Bosch process for fertilizer production. Within this work, it was investigated to what extent and under which conditions Carpathian clinoptilolite powder (CCP 20) can be used to remove ammonium from SW and to recover it. Two different SW, originating from municipal WWTPs were investigated (SW1: c₀ = 967 mg/L NH₄-N, municipal wastewater; SW2: c₀ = 718–927 mg/L NH₄-N, large industrial wastewater share). The highest loading was achieved at 307 K with 16.1 mg/g (SW1) and 15.3 mg/g (SW2) at 295 K. Kinetic studies with different specific dosages (0.05 g_CLI/mg_NH4-N), temperatures (283–307 K) and pre-loaded CCP 20 (0–11.4 mg/g) were conducted. At a higher temperature a higher load was achieved. Already after 30 min contact time, regardless of the sludge water, a high load up to 7.15 mg/g at 307 K was reached, achieving equilibrium after 120 min. Pre-loaded sorbent could be further loaded with ammonium when it was recontacted with the SW.     

Study of the Molecular Mobility in Polymers with the Thermally Stimulated Recovery Technique—A Review

Thermally stimulated recovery (TSR) is a non‐conventional mechanical spectroscopy technique that allows to analyse in detail the relaxation processes of polymeric systems in the low frequency region. This work reviews the main aspects and potentialities of this technique. The different kinds of TSR experiments that can be performed, global and thermal sampling (TS) experiments, are described and illustrated with several examples. Also, the different methods for the determination of the thermokinetic parameters (activation energy and pre‐exponential factor) of the thermal sampling (TS) procedure are explained and compared. In this context, the compensation phenomenon, which always appears in TSR results when the studies are performed in the glass transition region of a given system, is discussed. Examples of the application of this technique to different polymeric systems during the last 20 years are provided. An emphasis will be made on the analysis of the effect of crystallinity degree and crosslink density on the TSR response. A comparison between the results (characteristic times and activation energies) obtained by different techniques, namely TSR, dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC), is made.     

Contralaterally transplanted human embryonic stem cell-derived neural precursor cells (ENStem-A) migrate and improve brain functions in stroke-damaged rats

The transplantation of neural precursor cells (NPCs) is known to be a promising approach to ameliorating behavioral deficits after stroke in a rodent model of middle cerebral artery occlusion (MCAo). Previous studies have shown that transplanted NPCs migrate toward the infarct region, survive and differentiate into mature neurons to some extent. However, the spatiotemporal dynamics of NPC migration following transplantation into stroke animals have yet to be elucidated. In this study, we investigated the fates of human embryonic stem cell (hESC)-derived NPCs (ENStem-A) for 8 weeks following transplantation into the side contralateral to the infarct region using 7.0T animal magnetic resonance imaging (MRI). T2- and T2*-weighted MRI analyses indicated that the migrating cells were clearly detectable at the infarct boundary zone by 1 week, and the intensity of the MRI signals robustly increased within 4 weeks after transplantation. Afterwards, the signals were slightly increased or unchanged. At 8 weeks, we performed Prussian blue staining and immunohistochemical staining using human-specific markers, and found that high percentages of transplanted cells migrated to the infarct boundary. Most of these cells were CXCR4-positive. We also observed that the migrating cells expressed markers for various stages of neural differentiation, including Nestin, Tuj1, NeuN, TH, DARPP-32 and SV38, indicating that the transplanted cells may partially contribute to the reconstruction of the damaged neural tissues after stroke. Interestingly, we found that the extent of gliosis (glial fibrillary acidic protein-positive cells) and apoptosis (TUNEL-positive cells) were significantly decreased in the cell-transplanted group, suggesting that hESC-NPCs have a positive role in reducing glia scar formation and cell death after stroke. No tumors formed in our study. We also performed various behavioral tests, including rotarod, stepping and modified neurological severity score tests, and found that the transplanted animals exhibited significant improvements in sensorimotor functions during the 8 weeks after transplantation. Taken together, these results strongly suggest that hESC-NPCs have the capacity to migrate to the infarct region, form neural tissues efficiently and contribute to behavioral recovery in a rodent model of ischemic stroke.     

Neuronal RNA granule contains ApCPEB1, a novel cytoplasmic polyadenylation element binding protein, in Aplysia sensory neuron

The cytoplasmic polyadenylation element (CPE)-binding protein (CPEB) binds to CPE containing mRNAs on their 3'' untranslated regions (3''UTRs). This RNA binding protein comes out many important tasks, especially in learning and memory, by modifying the translational efficiency of target mRNAs via poly (A) tailing. Overexpressed CPEB has been reported to induce the formation of stress granules (SGs), a sort of RNA granule in mammalian cell lines. RNA granule is considered to be a potentially important factor in learning and memory. However, there is no study about RNA granule in Aplysia. To examine whether an Aplysia CPEB, ApCPEB1, forms RNA granules, we overexpressed ApCPEB1-EGFP in Aplysia sensory neurons. Consistent with the localization of mammalian CPEB, overexpressed ApCPEB1 formed granular structures, and was colocalized with RNAs and another RNA binding protein, ApCPEB, showing that ApCPEB1 positive granules are RNA-protein complexes. In addition, ApCPEB1 has a high turnover rate in RNA granules which were mobile structures. Thus, our results indicate that overexpressed ApCPEB1 is incorporated into RNA granule which is a dynamic structure in Aplysia sensory neuron. We propose that ApCPEB1 granule might modulate translation, as other RNA granules do, and furthermore, influence memory.     

驱油用聚丙烯酰胺分子量测试的光散射研究

利用旋转流变仪分析了超高分子量部分水解聚丙烯酰胺溶液的流变性质,并根据光散射动态模式分析了其在不同浓度和不同盐离子浓度下的尺寸分布.建立了利用多角度激光光散射准确测量驱油用超高分子量聚丙烯酰胺重均分子量(Mw)、均方根回转半径()和第二位力系数值(A2)的方法.准确测量了商品化驱油用超高分子量聚丙烯酰胺FP3630S的这3个参数,分别为Mw=(1.33±0.06)×107,     

Biosurfactants from potato process effluents

High-solids (HS) and low-solids (LS) potato process effluents were tested as substrates for surfactin production. Tests used effluents diluted 1∶10, unamended and amended with trace minerals or corn steep liquor. Heat pretreatment was necessary for surfactin production from effluents due to indigenous bacteria, whose spores remained after autoclaving. Surfactin production from LS surpassed HS in all cases. Surfactin yields from LS were 66% lower than from a pure culture in an optimized potatostarch medium. LS could potentially be used without sterilization for surfactin production for low-value applications such as environmental remediation or oil recovery.     

磷钼杂多化合物脱硫热力学可行性与硫磺生成机理研究

长期以来杂多化合物一直被用作特定反应的催化剂 ,尚无直接利用其氧化还原性能进行污染物治理研究的先例 [1] .由于磷和钼在我国均为丰产元素 ,相应的杂多化合物又具有稳定的化学性能 ,寻找其新的应用领域无疑具有特别重要的意义 .本文对与此相关的脱硫热力学可行性与硫磺生成机理问题进行研究 ,以期为应用开发奠定理论基础 .1　实验部分1 .1　仪器和试剂　 31 4型硫离子选择电极 (江苏电分析仪器厂 ) ;DSC- 7型微分量热仪 (美国 Perkin-Elmer公司 ) ;Finber 1 0 0 0型能谱分析仪 (配置 Pioneer KYKY2 80 0型扫描电镜 ) ;UJ33a型电位…     

Simultaneous Spectrophotometric Estimation of Rabeprazole Sodium and Itopride HCl

Abstract

Two simple, rapid, accurate, and economical analytical methods have been developed for the simultaneous estimation of Rabeprazole Sodium and Itopride Hydrochloride in combined capsule dosage form. First method is based on the determination of Q‐value and second method is based on simultaneous equation method. Rabeprazole Sodium has absorbance maxima at 284 nm and Itopride Hydrochloride has absorbance maxima at 258 nm in methanol AR. The absorption ratio (Q‐value) was determined at 266.6 nm (Iso‐bestic point) and 284 nm (λmax of Rabeprazole Sodium). Both the drugs obey Beer's law in the concentration ranges employed for these methods. Both the methods were found to be simple, rapid, accurate, and can be adopted in routine analysis of drugs in formulations. The accuracy and reproducibility of the proposed method was statistically validated by recovery studies