刺激响应型可注射水凝胶在药物控释领域的研究进展

可注射水凝胶作为一种新兴的智能生物材料,由于其可以精准植入组织部位,实现高靶向性原位成形、原位给药、无需手术、创口小等特点,在生物医学领域显示出巨大的应用潜力。这类水凝胶可以通过物理或化学交联形成,具有良好的生物相容性和生物降解性,通过负载活性物质,在药物递送、组织工程等生物医用领域大有可为。刺激响应型水凝胶在感受到环境刺激时会改变形状或体积。当pH值、温度、光照、电磁场或酶等条件发生变化时,它们的体积会膨胀或收缩,甚至发生降解。文中从内源性刺激(如pH值、温度、酶和葡萄糖)和外源性刺激(如光、电、磁场)2个方面,综述了刺激响应型可注射水凝胶的研究进展,重点介绍了内源性刺激(如pH值、温度、酶和葡萄糖)和外源性刺激(如光、电、磁场)相变机理、设计和合成策略及释药行为,并对可注射水凝胶开发中需应对的挑战与问题和未来发展提出了建议。

Improving dryland maize productivity and water efficiency with heterotrophic ammonia-oxidizing bacteria via nitrification and cytokinin activity

A two-year field experiment conducted under dryland conditions in semi-humid and drought-prone regions of China aimed to assess the effect of ammonia-oxidizing bacterial on maize water use efficiency and yield.A heterotrophic ammonia-oxidizing bacteria(HAOB)strain S2_8_1 was used.Six treatments were applied:(1)no irrigation+HAOB strain(DI),(2)no irrigation+blank culture medium(DM),(3)no irrigation control(DCK),(4)irrigation+HAOB(WI),(5)irrigation+blank culture medium(WM),and(6)irrigation control(WCK).Results revealed that HAOB treatment increased maize growth,yield,and water use efficiency over controls,regardless of whether the year was wet or dry.This improvement was attributed to the accelerated nitrification in the rhizosphere soil due to HAOB inoculation,which subsequently led to increased levels of leaf cytokinins.Overall,these findings suggest that HAOB inoculation holds promise as a strategy to boost water use efficiency and maize productivity in dryland agriculture.

磁性纳米粒子的制备及在生物医学领域中的应用概述

磁性纳米材料由于具有优异的纳米效应和磁性能,在生物医药领域可广泛应用于磁靶向、磁热疗、药物递送、生物分离等方面,并已作为核磁共振造影剂应用于临床。通过将不同类型的聚合物基质与磁性纳米填料结合在一起,可开发出多种类型的磁性纳米复合功能材料。文中综述了磁性纳米粒子领域的最新动态,详细阐述了磁性纳米粒子的制备方法和改性技术,讨论了磁性纳米粒子复合材料在药物载体、核磁共振成像、磁热疗等生物医学领域的应用前景。

普朗尼克胶束用于抗癌药物阿霉素的负载和释放

为了研究阿霉素胶束中药物的存在形式及其与胶束释药行为的关系,以不同类型的普朗尼克胶束为载体材料制备了3种阿霉素胶束。普朗尼克载药胶束首先由阿霉素盐酸盐和脱氧胆酸钠通过静电相互作用形成复合物,然后通过亲疏水性作用封装到普朗尼克胶束的疏水段形成。以载药量和包封率为评价指标,动态光散射法测定其粒径大小及其分布、透析法测定载药胶束的体外释放行为。结果表明,制备的普朗尼克F127,F128,F68胶束的载药量分别为(0.15±0.11)%,(0.16±0.07)%和(0.17±0.1)%,包封率分别为(3.03±0.24)%,(3.11±0.15)%和(3.36±0.02)%。载药胶束的粒径分布均匀。在690 min内累计释放率均能达到70%以上,且无显著性差异。本文成功制备了均一、稳定的普朗尼克载药胶束,研究了不同普朗尼克载药胶束的药物释放行为,为药物输送系统提供理论依据和参考。

导电水凝胶的构筑设计及应用

水凝胶因其优良的物理化学性能和生物学特性,被广泛应用于生物医药、功能材料和传感器等领域。导电水凝胶作为一种新型功能凝胶材料,受到了广大科研工作者的青睐。通过将不同类型的聚合物基质与导电填料结合在一起,开发出了多种类型的导电聚合物水凝胶(ECHs)。文中综述了导电水凝胶研究领域的最新动态,详细阐述了导电水凝胶的设计和构筑方法,并讨论了导电水凝胶材料在生物医学和储能系统等领域的应用前景。导电水凝胶材料的构筑、设计和应用研究将促进电子功能材料领域的快速发展。

Neuronal apoptosis in cerebral ischemia/reperfusion area following electrical stimulation of fastigial nucleus

Previous studies have indicated that electrical stimulation of the cerebellar fastigial nucleus in rats may reduce brain infarct size, increase the expression of Ku70 in cerebral ischemia/ reperfusion area, and decrease the number of apoptotic neurons. However, the anti-apoptotic mechanism of Ku70 remains unclear. In this study, fastigial nucleus stimulation was given to rats 24, 48, and 72 hours before cerebral ischemia/reperfusion injury. Results from the electrical stim- ulation group revealed that rats exhibited a reduction in brain infarct size, a significant increase in the expression of KuT0 in cerebral ischemia/reperfusion regions, and a decreased number of terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL）-positive cells. Double immunofluorescence staining revealed no co-localization of Ku70 with TUNEL-positive cells. However, Ku70 partly co-localized with Bax protein in the cytoplasm of rats with cerebral ischemia/reperfusion injury. These findings suggest an involvement of Ku70 with Bax in the cy- toplasm of rats exposed to electrical stimulation of the cerebellar fastigial nucleus, and may thus provide an understanding into the anti-apoptotic activity of KuT0 in cerebral ischemia/reperfu- sion injury.

Numerical Simulation of Dam-Break Flooding of Cascade Reservoirs

Previous studies at home and abroad have mainly focused on single dam-break, and little attention has been paid so far to the dam-break of cascade reservoirs. Multi-source flooding, which can lead to three-dimensional turbulent phenomena and superposition effects, is the main difference between the dam-break of cascade and single reservoirs. Detailed descriptions of the coupled numerical simulation of multi-source flooding have little been reported, and the initial wet riverbed is rarely considered in current models. Therefore, in this paper, a method based on the three-dimensional (Formula presented.) turbulence model coupled with the volume-of-fluid method is proposed to simulate the dam-break flooding of cascade reservoirs. The upstream river, reservoir, and downstream river are connected by the internal boundary method, and the initial conditions, including river flow and reservoir water, are determined according to the results of the numerical simulation. Coupled numerical simulation of different dam-break flooding is then achieved. The present work solves the challenges presented by the enhancement and superposition of natural river flow, upstream flooding, and downstream flooding. This paper provides a theoretical basis for future studies on the dam-break flood routing of cascade reservoirs. © 2017 Tianjin University and Springer-Verlag GmbH Germany

Channel Stability Analysis by One-Way Fluid Structure Interaction: A Case Study in China

Channel engineering stability with underground goafs is a complex three-dimensional problem, especially when considering channel leakage, and is influenced by a number of processes, such as seepage, fluid structure interaction (FSI), modeling, and selection of geological mechanical parameters. In this study, stability finite element analysis by one-way FSI was performed by establishing an integrated 3D engineering geological model. The extended Fourier amplitude sensitivity test was used to quantitatively assess the first-order and total sensitivities of the engineering model to critical geological mechanical parameters. Results illustrate that the channel engineering deformation is under a reasonable range and the elastic modulus is the highest total sensitivity parameter for the channel tilt and curvature at 0.7395 and 0.7525, respectively. Moreover, the most observable coupling effects for the curvature and horizontal strain are cohesion (0.1933) and density (0.7410), respectively. © 2017, Tianjin University and Springer-Verlag GmbH Germany.

RAPD Analysis of Rosa laevigata Michx. from Different Origins

[ Objective] This study aimed to investigate the genetic diversity and phylogenetic relationship of 30 populations of Rosa laevigata Michx. from different origins. [ Method] Using RAPD molecular marker technique, eight effective primers were screened from 35 RAPD random primers for amplification. UPGMA clus- ter analysis was performed using NTSYSpc. ver. 2.02 software. [ Result] A total of 86 loci were amplified using the screened primers, including 84 polymorphic loci, indicating an average polymorphic percentage （PPB） of 97.67%. The similarity coefficients of 30 populations of R. laevigata Michx. ranged from O. 11 to O. 58, and these populations were clustered into groups A, B and C. [ Conclusion ] R. laevigata Michx. exhibits multiple genetic polymorphism. R. laevigata Michx. populations from Guizhou Province have closer genetic relationships.

Evaluation of Farmland Drainage Water Quality by Fuzzy–Gray Combination Method

The complex relationships between indicators and water conditions cause fuzzy and gray uncertainties in evaluation of water quality. Compared to conventional single-factor evaluation methods, the combination evaluation method can consider these two uncertainties to produce more objective and reasonable evaluation results. In this paper, we propose a combination evaluation method with two main parts:(1) the use of fuzzy comprehensive evaluation and gray correlation analysis as submodels with which to consider the fuzzy and gray uncertainties and(2) the establishment of a combination model based on minimum bias squares. In addition, using this method, we evaluate the water quality of a ditch in a typical rice–wheat system of Yixing city in the Taihu Lake Basin during three rainfall events. The results show that the ditch water quality is not good and we found the chemical oxygen demand to be the key indicator that affects water quality most significantly. The proposed combination evaluation method is more accurate and practical than single-factor evaluation methods in that it considers the uncertainties of fuzziness and grayness.

Research on Human Activity Recognition Algorithm Based on LSTM-1DCNN

With the rapid advancement of wearable devices,Human Activities Recognition(HAR)based on these devices has emerged as a prominent research field.The objective of this study is to enhance the recognition performance of HAR by proposing an LSTM-1DCNN recognition algorithm that utilizes a single triaxial accelerometer.This algorithm comprises two branches:one branch consists of a Long and Short-Term Memory Network(LSTM),while the other parallel branch incorporates a one-dimensional Convolutional Neural Network(1DCNN).The parallel architecture of LSTM-1DCNN initially extracts spatial and temporal features from the accelerometer data separately,which are then concatenated and fed into a fully connected neural network for information fusion.In the LSTM-1DCNN architecture,the 1DCNN branch primarily focuses on extracting spatial features during convolution operations,whereas the LSTM branch mainly captures temporal features.Nine sets of accelerometer data from five publicly available HAR datasets are employed for training and evaluation purposes.The performance of the proposed LSTM-1DCNN model is compared with five other HAR algorithms including Decision Tree,Random Forest,Support Vector Machine,1DCNN,and LSTM on these five public datasets.Experimental results demonstrate that the F1-score achieved by the proposed LSTM-1DCNN ranges from 90.36%to 99.68%,with a mean value of 96.22%and standard deviation of 0.03 across all evaluated metrics on these five public datasets-outperforming other existing HAR algorithms significantly in terms of evaluation metrics used in this study.Finally the proposed LSTM-1DCNN is validated in real-world applications by collecting acceleration data of seven human activities for training and testing purposes.Subsequently,the trained HAR algorithm is deployed on Android phones to evaluate its performance.Experimental results demonstrate that the proposed LSTM-1DCNN algorithm achieves an impressive F1-score of 97.67%on our self-built dataset.In conclusion,the fusion of temporal and spatial information in the measured data contributes to the excellent HAR performance and robustness exhibited by the proposed 1DCNN-LSTM architecture.

Cascade Human Activity Recognition Based on Simple Computations Incorporating Appropriate Prior Knowledge

The purpose of Human Activities Recognition(HAR)is to recognize human activities with sensors like accelerometers and gyroscopes.The normal research strategy is to obtain better HAR results by finding more efficient eigenvalues and classification algorithms.In this paper,we experimentally validate the HAR process and its various algorithms independently.On the base of which,it is further proposed that,in addition to the necessary eigenvalues and intelligent algorithms,correct prior knowledge is even more critical.The prior knowledge mentioned here mainly refers to the physical understanding of the analyzed object,the sampling process,the sampling data,the HAR algorithm,etc.Thus,a solution is presented under the guidance of right prior knowledge,using Back-Propagation neural networks(BP networks)and simple Convolutional Neural Networks(CNN).The results show that HAR can be achieved with 90%–100%accuracy.Further analysis shows that intelligent algorithms for pattern recognition and classification problems,typically represented by HAR,require correct prior knowledge to work effectively.

动态超分子化学作用构筑自愈合材料研究进展

超分子作用是一种非共价键作用,主要代表有氢键、金属配位、主客体相互作用等,大量的超分子作用聚集在一起可以形成力学强度高的动态系统。因此,基于动态超分子化学作用构筑自愈合材料引起了许多学者的研究兴趣。文中重点介绍了超分子动态化学的概念和历史,并在此基础上分别阐述了用于构筑自修复作用材料的不同超分子作用,即氢键、金属-配体、离子相互作用、主客体识别和π-π相互作用等。基于动态超分子化学作用构筑自愈合材料,为智能材料的设计和制备提供了理论基础和科学价值。

Chlorophyll Fluorescence, Photosynthetic and Morphological Characteristics of Waterlogged Sesame Seedlings

Two sesame accessions, ZZM2541 and Ezhi-2, with different tolerance to waterlogging were selected, and the seedlings at the 4-true leaf stage were treated by waterlogging for 48 h. Growth parameters were evaluated 1 d before the beginning of waterlogging and on the 3^(rd)day after the removal of waterlogging(DARW). Morphological characteristics of root and chlorophyll fuorescence were measured on the 3^(rd)DARW and leaf gas exchange was measured on the zero, 3^(rd)and 15^(th) DARW. Results showed that sesame accessions ZZM2541 and Ezhi-2 responded to waterlogging in considerably different performance. The stress induced leaf chlorosis and abscission and slowed growth of plant height in both accessions, but symptom occurred seriously in the susceptive Ezhi-2. In the more tolerant ZZM2541, plentiful of adventitious roots formed above the level.All of the average values of maximum fuorescence yield(F_m), quantum efficiency of open PSII centres(F_v/F_m), initial fluorescence(F_v/F_0) and chlorophyll content(Chl) decreased at the 4-true leaf stage in both accessions after suffering to the stress.The decreases of F_m, F_v/F_0 and Chl were more pronounced in Ezhi-2 than in ZZM2541. Less reductions of mean photosynthetic rate(Pn), transpiration rate(Tr), and stomatal conductance(gs) were observed in the leaves of waterlogged ZZM2541 than in waterlogged Ezhi-2(compared to controls), and the leaves of Ezhi-2 showed a higher water use efficiency(WUE) after the removal of waterlogging. Based on the results, it was concluded that the tolerance to waterlogging of ZZM2541 appears to depend on a combination of photosynthetic characteristics responses and morphological adaption.

NATURAL HISTORY OBSERVATION FOR ESOPHAGEAL AND CARDIA PRECURSORS BY REPETITIVE ENDOSCOPIC SCREENING OF 301 SUBJECTS IN SHEXIAN

OBJECTIVE To investigate the natural history of fast developing esophageal and cardia precursors.METHODS Repetitive endoscopic screenings were performed among 40-69-year-olds in the high-incidence areas for esophageal cancer in Shexian. RESULTS The initial diagnosis and the lag-time for 7 subsequently identified severe dysplasia （SD） subjects were as follows： in one subject 13 months after a baseline diagnosis of normal epithelium, in another subject 7 months after a baseline diagnosis of base cell hyperplasia （BCH）, in four subjects 3, 4, 4, and 10.5 months after baseline diagnosis of mild dysplasia （mD）, and in one subject 12.5 months after a baseline diagnosis of moderate dysplasia （MD）. The initial diagnosis and the lag-time for 6 subsequently identified carcinomas in situ or intramucosal carcinoma cases were： in one case 48 months after a baseline diagnosis of mD, in 2 cases 4 and 13 months after baseline diagnoses of MD, and in the other 3 cases 3.5, 9, and 17.5 months after baseline diagnoses of SD. The initial diagnosis and lag-time for 3 subsequently identified invasive cancer cases, were： in one case 50 months after a baseline diagnosis of MD, in 2 cases 14 and 19 months after baseline diagnoses of SD. In addition, during a 4-year-follow-up of 18 subjects after endoscopic mucosa resection, 9 of them were found to have developed precursors again at other sites, and also additional findings were obtained for 11 of the 16 dysplasia cases by repetitive biopsy in less than 2 months after the initial endoscopy. CONCLUSION A 5-year screening interval for BCH and mD, and a 3-year interval for MD may be too long for the fast developing precursors. Periodic screenings with shorter intervals should be considered to control the number of interval cases due to fast development, multifocal carcinogenesis, and false negative results inherent in one-time endoscopic biopsy sampling.

Identification of Four Gastrodia elata Bl. Variants with DNA Fingerprints

[Objective] This study aimed to investigate the four Gastrodia elata B1. variants at the DNA level. [Method] Primers with good reproducibility, abundant polymorphism and high resolution were selected from the 35 random primers with RAPD marker technology and the amplification results were analyzed. [ Result] By using RAPD technology, DNA fingerprints of four Gastrodia elata B1. variants with abundant polymorphism, good reproducibility and high resolution was successfully constructed; to be specific, each Gastrodia elata B1. variant has its unique fingerprint with primers S29 and S38 ; DNA bands of the Gastrodia elata BI. variants vary significantly, which is contributive to distinguish the four Gastrodia clara B1. variants. [Condusion] This study provided an effective means for the identification and protection of Gastrodia elata germplasms with intraspecific variations.

Correlations between Light Rare Earth Elements in Soil and Navel Orange Tree System in Gannan Area

The total content of light rare earth elements( LREEs) in the soil of navel orange orchards of Gannan area is greater than that of heavy rare earth elements( HREEs). Appropriate content of LREE can not only promote the growth of navel oranges,and it is also conducive to human health. On the basis of exploring the correlations between the content of LREE in the soil of navel orange orchards of Gannan area and the contents of LREE in navel orange leaves and fruit,the influence mechanism of LREEs on the quality of navel oranges was revealed. In this study,with two Newhall navel orange orchards with different soil LREEs background levels in Xinfeng County as the research object,the changes in the content of LREE( lanthanum,La; cerium,Ce; praseodymium,Pr; neodymium,Nd) in leaves and fruit of navel orange at different growth stages were analyzed using Inductively Coupled Plasma-Mass Spectrometry( ICP-MS),and the correlations between the content of LREE in the soil,navel orange leaves and navel orange fruit were studied. The results showed that the contents of the four kinds of LREEs in the soil ranked as Ce > La > Nd > Pr,and there were significant differences among them( P < 0. 01). Navel orange leaves and fruit have selective and heterogenic absorption for LREEs. At different growth stages,La showed the highest accumulation amount in the leaves and fruit of navel orange; and the content of LREE in the leaves of navel orange increased first and then decreased,while that in the fruit of navel orange showed continuous decrease. During the migration of LREEs from soil to leaves to fruit,the content of LREE decreased rapidly as the migration distance increased. The accumulation amount of LREE in navel orange was positively correlated with the content of LREE in the soil. The correlation between the content of LREE in the leaves and fruit of navel orange was greatest. Among the four kinds of LREEs,the correlation of La was greatest,followed by Ce,indicating that the accumulation amount of LREE in the navel orange body was affected by the element types.

Analysis of Lymph Node Metastases of 1,526 Cases with Thoracic Esophageal and Cardiac Carcinomas: A Random Sampling Report froni the Fourth Hospital of Hebei Medical University from 1996 to 2004

OBJECTIVE To summarize the regular pattern and state oflymph node metastasis of patients with esophageal and cardiaccarcinomas,so as to analyze factors influencing lymph nodemetastasis.METHODS Clinical data collected from 1,526 thoracicesophageal and cardiac carcinoma patients who were admitted inthe Fourth Hospital of Hebei Medical University during a periodfrom January 1996 to December 2004,were randomly selectedand an Access Database of the patient's information was set up.Eight clinico-pathologic factors,including the patient's age,tumorlocation and size,pathological classification,the depth of tumorinvasion,vascular tumor embolus (VTE),the state of surroundingorgan encroachment and the status of tumor residues,wereidentified.A correlation between these factors and metastases wasstatistically analyzed using SPSS13.0 software.RESULTS Lymph node metastatic sites from esophagealcarcinomas included the thoracic and abdominal cavity.Lymphnode metastasis from the superior esophageal carcinomasmainly occurred in the neck and thoracic cavity.There was atwo-way lymph node metastasis in the patients with the middleesophageal carcinoma.The inferior esophageal carcinomas mainlymetastasized to the paraesophageal,paragastric cardia,and leftgastric artery lymph nodes.The rate and degree of the metastasisfrom the inferior esophageal carcinomas were significantly highercompared to those of the superior and the middle esophagealcarcinomas (P<0.0125).The degree of abdominal lymph node metastasis fromcarcinomas of the gastric cardia was significantly higher comparedwith that of esophageal carcinomas.In the group with carcinomaof the gastric cardia,the rate and degree of the lymph nodemetastases in the paragastric cardia and left gastric artery weresignificantly higher compared to the group with esophagealcarcinoma (P<0.05).Paraesophageal lymph node metastasis fromcarcinomas of the gastric cardia in the thoracic cavity frequentlyoccurred,too,and the degree of the metastasis was similar to thatof esophageal carcinoma.There was no significant difference inthe rate and degree of the paraesophageal lymph-node metastasisbetween the group with carcinoma of the gastric cardia comparedto those with esophageal carcinoma (P>0.05).Multifactoriallogistic regression analysis showed that the tumor size,depth oftumor encroachment,VTE,and tumor residues could all bringabout obvious impact on lymph-node metastases (P<0.05).CONCLUSION Lymph node metastasis from superioresophageal carcinomas mainly occurs in the neck and thoraciccavity.The middle esophageal carcinomas presented a two-waylymph-node metastasis (both the upwards and the downwards),and the lymph node metastasis from inferior esophagealcarcinomas mainly occurred in the thoracic and abdominal cavities.The metastases of carcinoma of the gastriccardia were most commonly found in the abdominalcavity,with frequent paraesophageal lymph-nodemetastasis.The sufficient attention should be paidto neck lymph node clearance in cases of esophagealcarcinoma.What is of the greatest concern is theclearance of the left gastric artery lymph nodes,andalso in cases of gastric cardia carcinoma,clearance,the paraesophageal lymph nodes.With an increasein the tumor size and depth of tumor encroachment,and occurrence of VTE and tumor residual cells,therisk of lymph node metastasis is significantly raised (P<0.05).

The Rupture Degree of Graphs with k-Tree

A k-tree of a connected graph G is a spanning tree with maximum degree at most k. The rupture degree for a connected graph G is defined by , where and , respectively, denote the order of the largest component and number of components in . In this paper, we show that for a connected graph G, if for any cut-set , then G has a k-tree.

THE METRIC GENERALIZED INVERSE AND ITS SINGLE-VALUE SELECTION IN THE PRICING OF CONTINGENT CLAIMS IN AN INCOMPLETE FINANCIAL MARKET

This article continues to study the research suggestions in depth made by M.Z.Nashed and G.F.Votruba in the journal"Bull.Amer.Math.Soc."in 1974.Concerned with the pricing of non-reachable"contingent claims"in an incomplete financial market,when constructing a specific bounded linear operator A:l_(1)^(n)→l_(2) from a non-reflexive Banach space l_(1)^(n) to a Hilbert space l_(2),the problem of non-reachable"contingent claims"pricing is reduced to researching the(single-valued)selection of the(set-valued)metric generalized inverse A■ of the operator A.In this paper,by using the Banach space structure theory and the generalized inverse method of operators,we obtain a bounded linear single-valued selection A^(σ)=A+of A■.