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1.
For the estimation of copper, diethyldithiocarbamate method is most commonly employed in various laboratories where atomic
absorption spectrophotometer is not available. The prevalence rate of gastrointestinal malignancies is very high in Kashmir
as compared to other parts of the world. We could find high serum copper levels in gastrointestinal tract cancer. Intake of
salted tea, prepared in copper vessel, is very common in Kashmir. Such tea samples showed copper value as 3168.9 (S.D. 700.5)
μg/dl estimated by diethyldithiocarbamate method. When these samples analysed by atomic absorption spectrophotometer, the
copper levels were just 9% as reported by colorimetric method. Various black salted tea samples were prepared in the laboratory
in glass vessel. The mean copper was 1115.0 (S.D. 350.4) μg/dl. After addition of milk, the values were reduced by 50%. Nine
phenolic compounds showed varying amount of copper by colorimetric method and no copper could be detected by atomic absorption
spectrophotometer. Phenolic compounds present in tea leaves interfere in the estimation of copper by diethyldithiocarbamate
method. It is suggested that diethyldithiocarbamate colorimetric method for copper estimation is not suitable for solutions
containing phenolic compounds. 相似文献
2.
为利用赤铁矿、工业盐酸及硅酸钠为原料,制备聚硅酸氯化铁絮凝剂的方法并得出最佳条件,运用实验分析、文献分析及比较分析的方法,对聚硅酸氯化铁混凝性能进行了相关分析,并对聚硅酸氯化铁絮凝剂的性能进行了简要分析。结果表明,酸浸的温度、反应的时间、盐酸的浓度以及液固比均对铁的浸出有一定的影响,得到的最佳条件使铁的浸出率可达到94.58%;该方法制备的聚硅酸氯化铁絮凝剂pH适用范围较广,在整个中性和弱碱性范围内的处理效果较好;处理水的温度在10～30℃时,其效果较好;与市售的絮凝剂比较,在加药量相同的情况下,具有形成絮体速度较快,沉降速度快的优点。 相似文献
3.
We present a lossless Deoxyribonucleic Acid (DNA) sequence hiding method that can be used for ensuring authenticity of DNA sequence in the context of Mobile Cloud based healthcare systems. Hiding data within DNA sequence results in permanent information loss in DNA sequence. Therefore, providing DNA sequence authenticity using data hiding is challenging. Moreover, existing works on DNA data hiding require a reference DNA sequence data to retrieve hidden data. Hence, current methods are not blind approaches and inappropriate for ensuring authenticity of DNA sequence in the Mobile Cloud. The proposed method hides authentication data within DNA sequence, extracts authentication data, and reconstructs the DNA sequence without any loss of information. From there, our proposed approach guarantees DNA sequence authenticity and integrity in Mobile Cloud based healthcare systems. We present a security analysis of our method to show that the method is secured. We conduct several experiments to demonstrate the performance of our proposed method. 相似文献
4.
5.
DNA计算是解决困难问题的一种很重要的方法。应用DNA计算解决图论中的最小支撑树问题。利用DNA的热力学特性,根据边的权长不同,给它们设计不同溶解温度的DNA链。根据温度的不同,电泳时DNA分子的形状不同,电泳的速度也不同,从而根据电泳速度分离出最小支撑树的所有边。在这里给出了5个顶点的赋权图为例来求它的最小支撑树,说明了该方法的简便性。 相似文献
6.
应用聚合酶链反应（ＰＣＲ）检测了１５３例各型乙型肝炎患者的血清ＨＢＶＤＮＡ，并与ＥＬＩＳＡ法检测的血清ＨＢｅＡｇ和抗ＨＢｅ结果比较．结果ＨＢｅＡｇ阳性８９例，ＰＣＲ法ＨＢＶＤＮＡ检出率为９２．１３％；抗ＨＢｅ阳性２７例，ＰＣＲ法ＨＢＶＤＮＡ检出率为５１．８５％；ｅ系统用性３７例，ＰＣＲ法ＨＢＶＤＮＡ检出率为４０．５４％．提示抗ＨＢｅ血清学转换不能作为乙型肝炎病毒复制与非复制、病变活动与静止的唯一指标，而应该用或同时用ＨＢＶＤＮＡ作为指标才可靠． 相似文献
7.
Particle focusing is an essential step in a wide range of applications such as cell counting and sorting. Recently, viscoelastic particle focusing, which exploits the spatially non-uniform viscoelastic properties of a polymer solution under Poiseuille flow, has attracted much attention because the particles are focused along the channel centerline without any external force. Lateral particle migration in polymer solutions in square channels has been studied due to its practical importance in lab-on-a-chip applications. However, there are still many questions about how the rheological properties of the medium alter the equilibrium particle positions and about the flow rate ranges for particle focusing. In this study, we investigated lateral particle migration in a viscoelastic flow of DNA solution in a square microchannel. The elastic property is relevant due to the long relaxation time of a DNA molecule, even when the DNA concentration is extremely low. Further, the shear viscosity of the solution is essentially constant irrespective of shear rate. Our current results demonstrate that the particles migrate toward the channel centerline and the four corners of a square channel in the dilute DNA solution when the inertia is negligible (elasticity-dominant flow). As the flow rate increases, the multiple equilibrium particle positions are reduced to a single file along the channel centerline, due to the elasto-inertial particle focusing mechanism. The current results support that elasto-inertial particle focusing mechanism is a universal phenomenon in a viscoelastic fluid with constant shear viscosity (Boger fluid). Also, the effective flow rate ranges for three-dimensional particle focusing in the DNA solution were significantly higher and wider than those for the previous synthetic polymer solution case, which facilitates high throughput analysis of particulate systems. In addition, we demonstrated that the DNA solution can be applied to focus a wide range of particle sizes in a single channel and also align red blood cells without any significant deformation. 相似文献
8.
生物芯片技术和DNA计算分别是近几年来生命科学与信息科学的新兴研究领域,DNA计算在求解NP问题上存在着硅计算无法比拟的先天优越性。而图的最小顶点覆盖问题是图论中的一个重要问题,目前还没有好的算法。在DNA计算和DNA计算芯片的基础上,采用分子信标编码策略,利用观察荧光来确定图的最小顶点覆盖问题的可行解。利用分子信标模型来解决图的最小顶点覆盖M题,和其它DNA计算方法相比,该方法操作起来更加方便。 相似文献
9.
Ordered deposition of elongated DNA molecules was achieved by the forced dewetting of a DNA solution droplet over a microstructured substrate. This technique allows trapping, uncoiling, and deposition of DNA fragments without the need of a physicochemical anchoring of the molecule and results in the combing of double stranded DNA from the edge of microwells on a polydimethylsiloxane (PDMS) substrate. The technique involves scanning a droplet of DNA solution caught between a movable blade and a PDMS substrate containing an array of microwells. The deposition and elongation appears when the receding meniscus dewets microwells, the latter acting here as a perturbation in the dewetting line forcing the water film to break locally. Thus, DNA molecules can be deposited in an ordered manner and elongated conformation based solely on a physical phenomenon, allowing uncoiled DNA molecules to be observed in all their length. However, the exact mechanism that governs the deposition of DNA strands is not well understood. This paper is an analysis of the physical phenomenon occurring in the deposition process and is based on observations made with the use of high frame/second rate video microscopy. 相似文献
10.
目的:建立广西产地钱(Marchantia polymorpha L.)拳卷地钱(Marchantia convoluta gao et chang.)和粗裂地钱(Marchantia paleacea Bertol.)的分子鉴别方法。方法:利用RAPD(random amplified polymorphic DNA)技术。结果:采用改良的CTAB法提取地钱、拳卷地钱、粗裂地钱3种植物的总DNA均适用于22引物对供试材料DNA进行随机扩增,共扩增出145条谱带,多态性条带128条,占扩增总条带的88.3%,平均多态性百分率为89.8%;三种地钱遗传距离为0.3713-0.4107、Nei′s遗传一致度为0.5893-0.6287。结论:RAPD技术对广西产地钱、拳卷地钱、粗裂地钱进行分子鉴定是有效的。RAPD分析。 相似文献
11.
Shuaiqin Wang Yujia Sun Wupeng Gan Yan Liu Guangxin Xiang Dong Wang Lei Wang Jing Cheng Peng Liu 《Biomicrofluidics》2015,9(2)
We present an integrated microfluidic device capable of performing single-stranded DNA (ssDNA) preparation and magnetic bead-based microarray analysis with a white-light detection for detecting mutations that account for hereditary hearing loss. The entire operation process, which includes loading of streptavidin-coated magnetic beads (MBs) and biotin-labeled polymerase chain reaction products, active dispersion of the MBs with DNA for binding, alkaline denaturation of DNA, dynamic hybridization of the bead-labeled ssDNA to a tag array, and white-light detection, can all be automatically accomplished in a single chamber of the microchip, which was operated on a self-contained instrument with all the necessary components for thermal control, fluidic control, and detection. Two novel mixing valves with embedded polydimethylsiloxane membranes, which can alternately generate a 3-μl pulse flow at a peak rate of around 160 mm/s, were integrated into the chip for thoroughly dispersing magnetic beads in 2 min. The binding efficiency of biotinylated oligonucleotides to beads was measured to be 80.6% of that obtained in a tube with the conventional method. To critically test the performance of this automated microsystem, we employed a commercial microarray-based detection kit for detecting nine mutation loci that account for hereditary hearing loss. The limit of detection of the microsystem was determined as 2.5 ng of input K562 standard genomic DNA using this kit. In addition, four blood samples obtained from persons with mutations were all correctly typed by our system in less than 45 min per run. The fully automated, “amplicon-in-answer-out” operation, together with the white-light detection, makes our system an excellent platform for low-cost, rapid genotyping in clinical diagnosis. 相似文献
12.
We have used Brownian dynamics-finite element method to examine two conformational preconditioning approaches for improving DNA stretching in a microcontraction for the purpose of direct gene analysis. The newly proposed "pre-stretching" strategy is found to significantly improve the degree of DNA extension at the exit of the contraction. On the other hand, applying an oscillating extensional field to DNA yields no preconditioning effect. Detailed analysis of the evolution of DNA extension and conformation reveals that the success of our "pre-stretching" strategy relies on the "non-local" effect that cannot be predicted using simple kinematics analysis. In other words, accurate prediction can only be obtained using detailed simulations. Comparing to the existing preconditioning strategies, our "pre-stretching" method is easy to implement while still providing a very good performance. We hope that the insight gained from this study can be useful for future design of biomicrofluidic devices for DNA manipulation. 相似文献
13.
Found in all eukaryotic cells, linker histones H1 are known to bind to and rearrange nucleosomal linker DNA. In vitro, the fundamental nature of H1∕DNA interactions has attracted wide interest among research communities-from biologists to physicists. Hence, H1∕DNA binding processes and structural and dynamical information about these self-assemblies are of broad importance. Targeting a quantitative understanding of H1 induced DNA compaction mechanisms, our strategy is based on using small-angle x-ray microdiffraction in combination with microfluidics. The usage of microfluidic hydrodynamic focusing devices facilitates a microscale control of these self-assembly processes, which cannot be achieved using conventional bulk setups. In addition, the method enables time-resolved access to structure formation in situ, in particular, to transient intermediate states. The observed time dependent structure evolution shows that the H1∕DNA interaction can be described as a two-step process: an initial unspecific binding of H1 to DNA is followed by a rearrangement of molecules within the formed assemblies. The second step is most likely induced by interactions between the DNA and the H1's charged side chains. This leads to an increase in lattice spacing within the DNA∕protein assembly and induces a decrease in the correlation length of the mesophases, probably due to a local bending of the DNA. 相似文献
14.
Multiple sample DNA amplification was done by using a novel rotary-linear motion polymerase chain reaction (PCR) device. A simple compact disc was used to create the stationary sample chambers which are individually temperature controlled. The PCR was performed by shuttling the samples to different temperature zones by using a combined rotary-linear movement of the disc. The device was successfully used to amplify up to 12 samples in less than 30 min with a sample volume of 5 μl. A simple spring loaded heater mechanism was introduced to enable good thermal contact between the samples and the heaters. Each of the heater temperatures are controlled by using a simple proportional–integral–derivative pulse width modulation control system. The results show a good improvement in the amplification rate and duration of the samples. The reagent volume used was reduced to nearly 25% of that used in conventional method. 相似文献
15.
Charles A. Zittle 《Journal of The Franklin Institute》1947,243(4):334-336
Desoxyribonucleic acid prepared by a method which utilizes strong NaOH was not acted on by a speciflc nuclease but it was extensively hydrolyzed by phosphoesterase from calf intestinal mucosa. Experiments indicated that the adenine radical is concerned in the resistance of the nucleic acid to the nuclease. 相似文献
16.
This study suggests a new erythrocyte sedimentation rate (ESR) measurement method for the biophysical assessment of blood by using a microfluidic device. For an effective ESR measurement, a disposable syringe filled with blood is turned upside down and aligned at 180° with respect to gravitational direction. When the blood sample is delivered into the microfluidic device from the top position of the syringe, the hematocrit of blood flowing in the microfluidic channel decreases because the red blood cell-depleted region is increased from the top region of the syringe. The variation of hematocrit is evaluated by consecutively capturing images and conducting digital image processing technique for 10 min. The dynamic variation of ESR is quantitatively evaluated using two representative parameters, namely, time constant (λ) and ESR-area (AESR). To check the performance of the proposed method, blood samples with various ESR values are prepared by adding different concentrations of dextran solution. λ and AESR are quantitatively evaluated by using the proposed method and a conventional method, respectively. The proposed method can be used to measure ESR with superior reliability, compared with the conventional method. The proposed method can also be used to quantify ESR of blood collected from malaria-infected mouse under in vivo condition. To indirectly compare with the results obtained by the proposed method, the viscosity and velocity of the blood are measured using the microfluidic device. As a result, the biophysical properties, including ESR and viscosity of blood, are significantly influenced by the parasitemia level. These experimental demonstrations support the notion that the proposed method is capable of effectively monitoring the biophysical properties of blood. 相似文献
17.
The vector space model (VSM) is a textual representation method that is widely used in documents classification. However, it remains to be a space-challenging problem. One attempt to alleviate the space problem is by using dimensionality reduction techniques, however, such techniques have deficiencies such as losing some important information. In this paper, we propose a novel text classification method that neither uses VSM nor dimensionality reduction techniques. The proposed method is a space efficient method that utilizes the first order Markov model for hierarchical Arabic text classification. For each category and sub-category, a Markov chain model is prepared based on the neighboring characters sequences. The prepared models are then used for scoring documents for classification purposes. For evaluation, we used a hierarchical Arabic text data collection that contains 11,191 documents that belong to eight topics distributed into 3-levels. The experimental results show that the Markov chains based method significantly outperforms the baseline system that employs the latent semantic indexing (LSI) method. That is, the proposed method enhances the F1-measure by 3.47%. The novelty of this work lies on the idea of decomposing words into sequences of characters, which found to be a promising approach in terms of space and accuracy. Based on our best knowledge, this is the first attempt to conduct research for hierarchical Arabic text classification with such relatively large data collection. 相似文献
18.
Alex Livy Sayhean Lye Chahil K. Jagdish Nurul Hanis Velapasamy Sharmila Lian Wee Ler Bagali Pramod 《Indian journal of clinical biochemistry : IJCB》2012,27(1):28-33
Buccal cell usage has been shown by many to be a cost effective and safe method to isolate DNA for various biological experiments
especially large epidemiological studies (Garcia-Closas et al. Cancer Epidemiol Biomarkers Prev 10:687–696, 2001). Non-invasive DNA collection methods are preferred over phlebotomy in order to increase study participation and compliance
in research centers and for sick patients in hospital settings. There have been conflicting reports about the methodology
and results obtained from using buccal DNA. It is not very clear if phlebotomy can be confidently replaced by buccal cell
DNA. It is often left for the user to take an intelligent decision. To address this issue, we compared the performance of
buccal and blood DNA from same subjects in a genotyping experiment and this paper reports the results. Cotton swab derived
buccal cells were scraped from the inner side of cheeks from 16 subjects, and blood was also drawn from the same 16 subjects
participating in a genotypic association study of a lipid disease. The DNA quality was assessed by resolving on agarose gels,
checking purity (A260/A280) and finally by microarray hybridization. This study showed that DNA degradation affects the total
yield and performance of the buccal DNA when compared to the blood DNA in microarray based genotyping. Genotyping results
can be seriously compromised if care is not taken to check the quality and yields of such specimens. 相似文献
19.
A simple method of fabricating mask-free microfluidic devices for biological analysis 总被引：1，自引：0，他引：1
We report a simple, low-cost, rapid, and mask-free method to fabricate two-dimensional (2D) and three-dimensional (3D) microfluidic chip for biological analysis researches. In this fabrication process, a laser system is used to cut through paper to form intricate patterns and differently configured channels for specific purposes. Bonded with cyanoacrylate-based resin, the prepared paper sheet is sandwiched between glass slides (hydrophilic) or polymer-based plates (hydrophobic) to obtain a multilayer structure. In order to examine the chip’s biocompatibility and applicability, protein concentration was measured while DNA capillary electrophoresis was carried out, and both of them show positive results. With the utilization of direct laser cutting and one-step gas-sacrificing techniques, the whole fabrication processes for complicated 2D and 3D microfluidic devices are shorten into several minutes which make it a good alternative of poly(dimethylsiloxane) microfluidic chips used in biological analysis researches. 相似文献