Browsing by Author "Zhang, Jian"
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Item Open Access Detection of TP53 mutation using a portable Surface Plasmon Resonance DNA-based biosensor(Elsevier, 2005-02-02T17:36:22Z) Jiang, Tieshan; Minunni, Maria E.; Wilson, P. K.; Zhang, Jian; Turner, Anthony P. F.; Mascini, MarcoA DNA-based Surface Plasmon Resonance (SPR) biosensor has been developed for the detection of TP53 mutation using the inexpensive and commercially available instrument, SPREETATM SPR-EVM-BT, from Texas Instruments. A direct immobilization procedure, based on the coupling of thiol-derivatised oligonucleotide probes (Probe-C6-SH) to bare gold sensor surfaces, was optimized using synthetic oligonucleotides. Hybridization reactions between the immobilized probe and a short sequence (26 mer) complementary, non-complementary and one point mutation DNA were then investigated. The main analytical parameters of the sensor system were studied in detail including selectivity, sensitivity, reproducibility and analysis time. Finally, the sensor system was successfully applied to polymerase chain reaction (PCR) amplified real samples, DNA extracted from both normal, wild type, (Jurkat) and mutated (Molt 4), carrying the mutation at codon 248 of the TP53 cell lines. The results obtained demonstrate that the DNA-based SPR biosensor was able to distinguish sequences present in the various samples that differ only by one base and hence it appears to be a strong candidate technique for the detection of gene mutation.Item Open Access Molecular dynamics study of effects of vacancy on phonon heat conductivity of copper(Cranfield University, 2015-09) Zhang, Jian; Jenkins, Karl W.Heat conductivity is an important property for solids, which exhibits their ability of transporting heat. It is composed of two parts, heat conductivity contributed by electrons and that by phonons. By experiments, heat conductivity of many materials has been calculated. For instance, Copper (Cu) has a good heat conductivity of about 400 W/mK, while the heat conductivity of glass (0.78 W/mK) is much less than it. Due to the high heat conductivity of Cu, it has been found in various applications, such as heat sinks and heat pipes. Although a great many researchers have investigated the heat conductivity of Cu in experiments, one can not understand the heat transfer mechanism in a view of microscopic. Molecular dynamics (MD) originated as a simulation method in the late 1950s. Due to the increasing advances in computer technology and algorithmic promotion, MD has become a precious tool in many fields of physics and chemistry. The phonon heat conductivity of perfect Cu has been investigated using MD. However, in reality, it is practically impossible to manufacture a piece of Cu without defects. Generally, there are a variety of defects, such as vacancy, dislocations and grain boundary, existing in materials. Note that vacancy is the simplest defect in materials. The objective of this research is to make a MD model and study the relationship between vacancy and phonon heat conductivity of Cu. Models are implemented mainly in four temperatures, 50 K, 300 K, 1000 K and 1300 K. The main finding is that the phonon heat conductivity decreases with the increasing vacancies. Following this realization, an analysis of the system is carried out to understand the mechanism of phonon heat transfer.