以放射性标记的肽核酸对目标基因的识别与检测

用放射性核素111In3+标记的肽核酸(PNA)为探针,分别检测与PNA序列互补的单链寡聚核苷酸、pUC19-C1质粒结合形成双螺旋的情况.结果表明,PNA不仅能够与游离单链的互补核酸形成稳定的双螺旋;还在有PNA开链剂存在的情况下,能够与靶位质粒特异性结合.以放射性标记的PNA可作为检测目标基因片断的有效分子探针.     

Adsorption and isolation of nucleic acids on cellulose magnetic beads using a three-dimensional printed microfluidic chip

While advances in genomics have enabled sensitive and highly parallel detection of nucleic acid targets, the isolation and extraction of the nucleic acids remain a critical bottleneck in the workflow. We present here a simple 3D printed microfluidic chip that allows for the vortex and centrifugation free extraction of nucleic acids. This novel microfluidic chip utilizes the presence of a water and oil interface to filter out the lysate contaminants. The pure nucleic acids, while bound on cellulose particles, are magnetically moved across the oil layer. We demonstrated efficient and rapid extraction of spiked Human Papillomavirus (HPV) 18 plasmids in specimen transport medium, in under 15 min. An overall extraction efficiency of 61% is observed across a range of HPV plasmid concentrations (5 × 10¹ to 5 × 10⁶ copies/100 μl). The magnetic, interfacial, and viscous drag forces inside the microgeometries of the chip are modeled. We have also developed a kinetics model for the adsorption of nucleic acids on cellulose functionalized superparamagnetic beads. We also clarify here the role of carrier nucleic acids in the adsorption and isolation of nucleic acids. Based on the various mechanistic insights detailed here, customized microfluidic devices can be designed to meet the range of current and emerging point of care diagnostics needs.     

Construction of nanocarriers based on nucleic acids and their applications in nanobiology delivery systemsOA

In recent years,nanocarriers based on nucleic acids have emerged as powerful and novel nanocarriers that are able to meet the demand for cancer-cell-specific targeting.Functional dynamics analysis revealed good bio compatibility,low toxicity and programmable structures,and their advantages include controllable size and modifiability.The development of novel hybrids has focused on the distinct roles of biosensing,drug and gene delivery,vaccine transport,photosensitization,counteracting drug resis...     

The magic angle and all that: probing the structure of solids using nuclear magnetic resonance

It has been known for some 25 years that much improved resolution of NMR spectra of solids can be achieved if the sample is rotated rapidly at a ‘magic’ angle of 54 °44′ to the magnetic field. However, the full potential of the method has been realised only within the past few years, largely because of the technical difficulties of establishing the correct conditions experimentally. It can now be applied to a wide range of problems in chemistry, materials science, and biology.     

Label-free isolation of a prostate cancer cell among blood cells and the single-cell measurement of drug accumulation using an integrated microfluidic chip

Circulating tumor cells (CTCs) are found in the blood of patients with cancer. Although these cells are rare, they can provide useful information for chemotherapy. However, isolation of these rare cells from blood is technically challenging because they are small in numbers. An integrated microfluidic chip, dubbed CTC chip, was designed and fabricated for conducting tumor cell isolation. As CTCs usually show multidrug resistance (MDR), the effect of MDR inhibitors on chemotherapeutic drug accumulation in the isolated single tumor cell is measured. As a model of CTC isolation, human prostate cancer cells were mixed with mouse blood cells and the label-free isolation of the tumor cells was conducted based on cell size difference. The major advantages of the CTC chip are the ability for fast cell isolation, followed by multiple rounds of single-cell measurements, suggesting a potential assay for detecting the drug responses based on the liquid biopsy of cancer patients.     

Effect of methyl mercury induced free radical stress on nucleic acids and protein: Implications on cognitive and motor functions

Mercury pollution and acute neurotoxicity of mercury is well known. The recent reports suggest the adverse effect of low dose mercury, though the available literature is still silent on its mechanism. This study was therefore undertaken to probe the effect of low dose methyl mercury induced heavy metal toxicity on free radical stress and its impact on behaviour of male albino rats. Male albino rats were exposed to 1 mg/kg body wt of methylmercury chloride for seven days, on day 8 they were tested for motor and memory functions. They were sacrificed later for biochemical estimations for rate of lipid peroxidation, nucleic acids, proteins in cerebrum, cerebellum and brain stem. There was an increase in the rate of lipid peroxidation showing methyl mercury induced free radical stress. The motor and memory functions demonstrated a clear decline, besides there was a lowering in the levels of nucleic acids and proteins as compared to controls. The results are important in view of recent reports that methyl mercury induced free radical stress results in early ageing and may serve as an initiating factor more specifically for neurodegenerative disorders like Alzeihemer's disease and dementias. The current findings support the notion that incorporating dietary antioxidants like curcumin, ascorbic acid and α-tocopherol in routine diet from early age may help combat the risk of developing such disorders in ensuing years.     

浅谈护理的设计和开发管理体系

本文根据GB／T19001-2000(idt ISO9001：2000)标准，对医院的“顾客”和“产品”的概念进行了说明，认为树立“顾客”的观念，以“顾客满意”为目标，是提高医院质量水平的前提，也是促进医院全面进步的需要；并对护理的设计和开发进行了探讨，将护理的设计和开发体系分为确定护理个案、护理诊断、设计护理计划、护理评审与验证、护理实施、护理评估和变更护理计划共8个阶段，对每个阶段的目的和内容进行了阐述；本文还对护理的设计和开发体系的策划和实施中应注意的问题进行了提示。     

Astudy on mycobacterial proteins in the serodiagnosis of tuberculosis using ELISA and western blot

Protein fraction termed P₂ was obtained from sonicates of Mycobacterium smegmatis, subjected to ammonium sulphate precipitation. P₂ fraction was further fractionated into 4 fractions (PeakI-IV) by DEAE cellulose ion-exchange chromatography. ELISA was performed on the sera of 104 tuberculous cases and 62 controls, using P₂ fractions Peak I as test antigens. Though the mean ELISA values in tuberculous cases were higher than the controls, no statistically significant difference was found between the two. Antigens P₂, Peak I and IV were tested on Western blots with pooled sera from tuberculous cases as well as controls. P₂ fraction, Peak-I and IV were separated on PAGE-SDS, electroblotted onto nitrocellulose Sheets and the blots were subjected to ELISA. Peak IV appeared as a single band (M.W. 55,000). P₂ fraction exhibited some discriminatory bands on development of blots.     

电子天平的使用与维护

本文介绍电子天平的分类及电子天平的基本使用和维护所要注意的一些问题,避免因使用不当而造成损坏。     

研究发展战略 实现跨越发展——广州能源研究所知识创新工程试点工作回顾

始建于 1978年的中国科学院广州能源研究所 ,2 0多年来 ,为国家经济建设和新能源与可再生能源领域的发展做出了重要贡献。在建所 2 0周年之际 ,我所被定位为中国科学院高技术研究与发展基地型研究所。 2 0 0 1年 6月 1日 ,进入院知识创新工程试点序列。按照院的总体部署和要求     

Quick chip assay using locked nucleic acid modified epithelial cell adhesion molecule and nucleolin aptamers for the capture of circulating tumor cells

The role of circulating tumor cells (CTCs) in disease diagnosis, prognosis, monitoring of the therapeutic efficacy, and clinical decision making is immense and has attracted tremendous focus in the last decade. We designed and fabricated simple, flat channel microfluidic devices polydimethylsiloxane (PDMS based) functionalized with locked nucleic acid (LNA) modified aptamers (targeting epithelial cell adhesion molecule (EpCAM) and nucleolin expression) for quick and efficient capture of CTCs and cancer cells. With optimized flow rates (10 μl/min), it was revealed that the aptamer modified devices offered reusability for up to six times while retaining optimal capture efficiency (>90%) and specificity. High capture sensitivity (92%) and specificity (100%) was observed in whole blood samples spiked with Caco-2 cells (10–100 cells/ml). Analysis of blood samples obtained from 25 head and neck cancer patients on the EpCAM LNA aptamer functionalized chip revealed that an average count of 5 ± 3 CTCs/ml of blood were captured from 22/25 samples (88%). EpCAM intracellular domain (EpICD) immunohistochemistry on 9 oral squamous cell carcinomas showed the EpICD positivity in the tumor cells, confirming the EpCAM expression in CTCs from head and neck cancers. These microfluidic devices also maintained viability for in vitro culture and characterization. Use of LNA modified aptamers provided added benefits in terms of cost effectiveness due to increased reusability and sustainability of the devices. Our results present a robust, quick, and efficient CTC capture platform with the use of simple PDMS based devices that are easy to fabricate at low cost and have an immense potential in cancer diagnosis, prognosis, and therapeutic planning.     

区域层面电子废弃物远景资源化潜力预测——以北京为例

电子废弃物回收利用具有区域性和长期性双重特征,区域层面电子废弃物远景资源化潜力分析可为国家循环产业布局及企业产能调整提供数据支撑.本文构建了区域层面电子废弃物远景资源化潜力预测模型(LRP模型),并引入Weibull分布模型对调研获得的产品寿命分布数据进行修正,引入Logistic分布模型对LRP模型的时间维度进行拓展...     

On the existence and the magnitude of electronic charges

In order to quantize Dirac's classical point electron¹ we supplement Einstein's classical equation (E/c)² ? p² = b2 with a reciprocal classical equation (CΔt)² ? (Δr)² = a² where b = mc and a is Dirac's signal radius. Δt is the time saved by a light signal in various states of motion of the electron, and a/c is the rest time saved. Our former efforts² of obtaining an integral equation for the probability amplitude have been rectified by Born.³ There is no solution of the integral equation, however, unless advanced and retarded phases are introduced simultaneously, along with Dirac's advanced and retarded potentials. We have obtained a transcendental equation for the eigen-value μ = αγ where α is the Sommerfeld fine-structure constant, and γ is the numerical factor in Dirac's signal radius a = γe²/mc². The smallest eigen-value is μ = 0.0299.That is, ab = hγ = h/210.     

浅谈电子招投标的发展及建议

本文对建设工程招投标中推行远程评标的作用和意义进行了论述;同时对电子评标在实际应用中存在的主要几个问题,包括电子招标投标安全可靠性缺乏制度保障、招标投标系统信息和功能不能共享等进行了研究,并针对这些主要问题提出了制定管理办法及建立信息平台促等解决对策,以保证促进整个招投标行业的健康高速发展。     

X-ray photoemission and the electronic structure of solids

The principles of X-ray photoelectron spectroscopy are outlined. The application of this technique to the study of the electronic structure of metals, alloys and compounds is illustrated using data in Ag, β-brass, ReO₃ and VO₂. In the latter a major change in the density of states is observed on passing through the metal-insulator transition.     

Comparative analysis of RBC membrane fatty acids, proteins and glycophorin in patients with heterozygous beta thalassemia and iron deficiency anemia

Membrane lipid and protein composition was compared in erythrocytes from iron deficiency anemia (IDA) and heterozygous beta thalassemia patients. The study was planned to correlate the influence of iron deficiency with the intrinsic defect of the heterozygous condition on the membrane structural integrity as well as to investigate whether there are differences in membrane changes between the two conditions. Results indicate high levels of saturated fatty acids and low unsaturated fatty acids in both disorders although arachidonic acid and the unsaturation index were lower in heterozygous thalassemia than IDA. Nevertheless, neither of the conditions provoked any alterations in membrane protein or glycophorin suggesting alterations in the lipid moiety only. Present findings indicate that irrespective to the etiology, both, iron deficiency and the heterozygous condition show a common pattern of lipid derangement, which may in turn result in increased membrane rigidity and decreased cellular deformability.     

电子政府与公共服务的改善

信息技术正以其广泛的适应性和强大的渗透性为公共服务提供强有力的技术支持,电子政府推动着公共服务的改善。本文在综述国内外电子政府理论研究的基础上,从三个方面分析了电子政府与公共服务改善的相关性:(1)电子政府与政府职能转变;(2)电子政府与公共服务程序改革;(3)电子政府与社区公众服务系统建立。     

Characterization of the near-field and convectional transport behavior of micro and nanoparticles in nanoscale plasmonic optical lattices

Here, we report the characterization of the transport of micro- and nanospheres in a simple two-dimensional square nanoscale plasmonic optical lattice. The optical potential was created by exciting plasmon resonance by way of illuminating an array of gold nanodiscs with a loosely focused Gaussian beam. This optical potential produced both in-lattice particle transport behavior, which was due to near-field optical gradient forces, and high-velocity (∼μm/s) out-of-lattice particle transport. As a comparison, the natural convection velocity field from a delocalized temperature profile produced by the photothermal heating of the nanoplasmonic array was computed in numerical simulations. This work elucidates the role of photothermal effects on micro- and nanoparticle transport in plasmonic optical lattices.