Integrated Microfluidic Isolation of Aptamers Using Electrophoretic Oligonucleotide Manipulation

We present a microfluidic approach to integrated isolation of DNA aptamers via systematic evolution of ligands by exponential enrichment (SELEX). The approach employs a microbead-based protocol for the processes of affinity selection and amplification of target-binding oligonucleotides, and an electrophoretic DNA manipulation scheme for the coupling of these processes, which are required to occur in different buffers. This achieves the full microfluidic integration of SELEX, thereby enabling highly efficient isolation of aptamers in drastically reduced times and with minimized consumption of biological material. The approach as such also offers broad target applicability by allowing selection of aptamers with respect to targets that are either surface-immobilized or solution-borne, potentially allowing aptamers to be developed as readily available affinity reagents for a wide range of targets. We demonstrate the utility of this approach on two different procedures, respectively for isolating aptamers against a surface-immobilized protein (immunoglobulin E) and a solution-phase small molecule (bisboronic acid in the presence of glucose). In both cases aptamer candidates were isolated in three rounds of SELEX within a total process time of approximately 10 hours

accelerating vehicle detection in low-altitude airborne urban video

The limitation of the existing methods of traffic data collection is that they rely on techniques that are strictly local in nature. The airborne system in unmanned aircrafts provides the advantages of wider view angle and higher mobility. However, detecting vehicles in airborne videos is a challenging task because of the scene complexity and platform movement. Most of the techniques used in stationary platforms cannot perform well in this situation. A new and efficient method based on Bayes model is proposed in this paper. This method can be divided into two stages, attention focus extraction and vehicle classification. Experimental results demonstrated that, compared with other representative algorithms, our method obtained better performance with higher detection rate, lower false positive rate and faster detection speed. © 2011 IEEE.National Natural Science Foundation of China; Chinese Academy of Science; Microsoft Research Asia; Xian Institute of Optics and Precision Mechanics of CAS; Anhui Crearo Technology Co., LtdThe limitation of the existing methods of traffic data collection is that they rely on techniques that are strictly local in nature. The airborne system in unmanned aircrafts provides the advantages of wider view angle and higher mobility. However, detecting vehicles in airborne videos is a challenging task because of the scene complexity and platform movement. Most of the techniques used in stationary platforms cannot perform well in this situation. A new and efficient method based on Bayes model is proposed in this paper. This method can be divided into two stages, attention focus extraction and vehicle classification. Experimental results demonstrated that, compared with other representative algorithms, our method obtained better performance with higher detection rate, lower false positive rate and faster detection speed. © 2011 IEEE

Remediation of deterioration in microbial structure in continuous Pinellia ternata cropping soil by crop rotation

Pinellia ternata is a traditional Chinese herb that suffers from continuous cropping (CC), which significantly decreases both yield and quality. The influence of CC on microbiome in P. ternata rhizosphere and the effects of remediation on microbiota by rotational cropping (CR) were assessed by Illumina high-throughput sequencing technology. CC tends to decrease the Îą-diversities along with cultivation time, whereas CR tends to increase them. Differentially abundant analysis showed that microbial structure was important in maintaining the health status of P. ternata rhizosphere. Results suggested that CC soils were mainly enriched for Pseudomonas, Rhizobium, and Streptophyta operational taxonomic units (OTUs), while the CR soils were mainly enriched for Rhizobium, Pseudomonas, Flavobacterium, Sphingomonas, Rhizobacter, and Arthrobacter OTUs. On the basis of the community dissimilarities, we grouped all sample replicates into three post hoc clusters in which soils were defined as healthy, health-suppressed, and health-depressed soils. The three soil types represented different soil physicochemical properties. The activities of the microbiome features, including ammonia oxidizer, sulfate reducer, nitrite reducer, dehalogenation, xylan degrader, sulfide oxidizer, nitrogen fixation, atrazine metabolism, chitin degradation, degraded aromatic hydrocarbons, and chlorophenol degradation, were also considerably different among the three soils.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

New Method to Determine Dynamic Meshing Force for Spur Gears Considering the Meshing State of Multiple Pairs of Teeth

The determination of meshing force and the load sharing ratio of gear teeth is critical to predict the dynamic behavior or the load capacity of gear transmissions. In the previous literature, the dynamic meshing force is usually calculated based on the traditional dynamic model, which ignores the different effects of the meshing characteristics of each pair of teeth on the dynamic behavior of the gear system. In this work, a new calculation method of dynamic meshing force is proposed based on the new dynamic model considering the meshing state of multiple pairs of teeth. The difference between the traditional calculation method and the new calculation method of dynamic meshing force is analyzed. Based on the new dynamic model and new calculation method of dynamic meshing force, the influence of different factors on dynamic response and dynamic meshing force are further discussed. The results show that, compared with the traditional calculation method, this new method can be used to effectively calculate the dynamic meshing force and the load sharing ratio of each pair of teeth with different meshing characteristics. The presented method for the calculation of the dynamic meshing force and the load sharing ratio provides an important reference for analyzing and predicting the dynamic behavior or the load capacity of spur gears, especially the high contact ratio (HCR) gears with contact ratio more than two

miR-344d-3p regulates osteogenic and adipogenic differentiation of mouse mandibular bone marrow mesenchymal stem cells

Postmenopausal osteoporosis (POP) is a chronic disease of bone metabolism that occurs in middle-aged and elderly women. POP can cause abnormalities of the skeletal system in the whole body, and the jaw bone is also impacted, affecting the function of the oral and maxillofacial regions. Mandibular bone marrow mesenchymal stem cells (MBMSCs) play an important role in mandibular bone metabolism, and abnormal differentiation of MBMSCs can affect the metabolic balance between new and old bone. MicroRNAs (miRNAs) can induce the differentiation of MBMSCs. In this study, the changes in biological characteristics of mandible and MBMSCs in the bone microenvironment of postmenopausal osteoporosis were firstly analyzed, and then the key miRNAs screened from miRNAs gene chips were sorted out for verification and functional exploration. It was found that miR-344d-3p promoted the osteogenic differentiation of MC3T3-E1 and MBMSCs. It inhibited the adipogenic differentiation of 3T3-L1 and MBMSCs. In addition, Dnmt3a may be the target gene of miR-344d-3p. In conclusion, this study found new biological indicators related to bone metabolism, which are of great significance in the field of bone reconstruction

Label-free microfluidic characterization of temperature-dependent biomolecular interactions

We present a microfluidic approach to characterizing temperature-dependent biomolecular interactions. Solvated L-arginine vasopressin (AVP) and its immobilized RNA aptamer (spiegelmer) were allowed to achieve equilibrium binding in a microchip at a series of selected temperatures. Unbound AVP were collected and analyzed with matrix-assisted laser desorption∕ionization mass spectrometry (MALDI-MS), yielding melting curves that reveal highly temperature-dependent zones in which affinity binding (36–45 °C) or dissociation (25–33 °C and 50–65 °C) occurs. Additionally, temperature-dependent binding isotherms were constructed; from these, thermodynamic quantities involved in binding were extracted. The results illustrated a strong change in heat capacity of interaction for this system, suggesting a considerable thermodynamic influence controlling vasopressin-spiegelmer interaction

Efficient One-Pot Synthesis of Uridine Diphosphate Galactose Employing a Trienzyme System

The limited availability of high-cost nucleotide sugars is a significant constraint on the application of their downstream products (glycosides and prebiotics) in the food or pharmaceutical industry. To better solve the problem, this study presented a one-pot approach for the biosynthesis of UDP-Gal using a thermophilic multienzyme system consisting of GalK, UGPase, and PPase. Under optimal conditions, a 2 h reaction resulted in a UTP conversion rate of 87.4%. In a fed-batch reaction with Gal/ATP = 20 mM:10 mM, UDP-Gal accumulated to 33.76 mM with a space-time yield (STY) of 6.36 g/L·h–1 after the second feeding. In repetitive batch synthesis, the average yield of UDP-Gal over 8 cycles reached 10.80 g/L with a very low biocatalyst loading of 0.002 genzymes/gproduct. Interestingly, Galk (Tth0595) could synthesize Gal-1P using ADP as a donor of phosphate groups, which had never been reported before. This approach possessed the benefits of high synthesis efficiency, low cost, and superior reaction system stability, and it provided new insights into the rapid one-pot synthesis of UDP-Gal and high-value glycosidic compounds