Complexly Organised Dynamical Systems

Both natural and engineered systems are fundamentally dynamical in nature: their defining properties are causal, and their organisational and functional capacities are causally grounded. Among dynamical systems, an interesting and important sub-class are those that are autonomous, anticipative and adaptive (AAA). Living systems, intelligent systems, sophisticated robots and social systems belong to this class, and the use of these terms has recently spread rapidly through the scientific literature. Central to understanding these dynamical systems is their complicated organisation and their consequent capacities for re- and self-organisation. But there is at present no general analysis of these capacities or of the requisite organisation involved. We define what distinguishes AAA systems from other kinds of systems by characterising their central properties in a dynamically interpreted information theory.     

Engineering in Genomics [variable number tandem repeats as agents of functional regulation in the genome]

The explosion of genetic data availability in the last decade has opened up many new avenues for the application of genetics to the improvement of human health, particularly, the common and complex disorders, which previously largely defied researchers seeking to understand their etiology. However, the utilization of this data in healthcare and by the pharmaceutical industry is still in its infancy, with the current focus being almost solely on two forms of genetic variation single nucleotide polymorphisms (SNPs), involving the substitution of one base in DNA for another and copy number variations, involving the deletion and multiplication of regions > 1,000 base pairs (bp). However, there is currently a relative paucity of funding and general interest in a third form of variation called microsatellites and mini- satellites.     

Is leptin sensitivity the link between smoking cessation and weight gain?

We performed a case-control study to investigate the association of the poor metaboliser genotype of the cytochrome P450 2D6 gene with Parkinson's disease (PD). Genotyping was determined by the polymerase chain reaction followed by digestion with restriction enzymes. The poor metaboliser genotype was more frequent in 112 patients with PD than in 206 matched controls (odds ratio 1.7, 95% CI: 0.94-2.45). A meta-analysis of these results together with ten other published studies gave a pooled odds ratio for the poor metaboliser genotype of 1.47 (95% CI: 1.18-1.96, P=0.01). Thus, the poor metaboliser genotype has a small but highly significant association with PD which would be easily missed in small studies. Research now should focus on the mechanism of this association.     

Systematic screening of the LDL-PLA2 gene for polymorphic variants and case-control analysis in schizophrenia

Systematic scans of the genome using microsatellite markers have identified chromosome 6p21.1 as a putative locus for schizophrenia in multiply affected families. There is also evidence from a series of studies for a role of abnormal phospholipid metabolism in schizophrenia. In light of these findings, and the role of platelet activating factor in neurotransmission and neurodevelopment, we have examined the LDL-PLA2 (plasma PAF acetylhydrolase, PAF-AH) gene, a serine dependent phospholipase that has been mapped by hybrid mapping to chromosome 6p21.1, as a positional candidate gene for schizophrenia. The gene was systematically screened using SSCP/HD analysis for polymorphisms associated with the disease. Four polymorphic variants were found within the gene and studied in a group of 200 schizophrenic patients and 100 controls. The variant in exon 7 (Iso195Thr) was found to be weakly associated with schizophrenia (p = 0.04) and the variant in exon 11 (Val379Ala) almost reached significance (p = 0.057). After correcting for multiple testing no significant associations were detected. Haplotype analysis combining pairs of polymorphisms also provided no evidence for association of this gene with schizophrenia in our sample of patients.     

Melt transformation coextrusion. I.

Using the Melt Transformation Coextrusion process it is possible to enhance the mechanical and thermal properties of polymeric extrudates directly from the melt and maintain continuous production rates. This adaption of melt transformation extrusion has significantly enhanced line speed compared to the precursor process. The required operating pressures in both processes are low enough to allow for the usage of commercial plasticating extruders as the polymer melt sources. Molecular orientation necessary to produce property enhancement is induced in the converging section of specially designed dies and retained by the core layer of the extrudate by imposing a steep temperature gradient in the land section of the die. Mechanical properties (i.e. tensile strength and modulus) and melting point elevation observed for the polypropylene core/polyethylene skin extrudates were functions of extrusion pressure. The highest values of these properties noted were: tensile modulus, 9.37 × 10⁵ psi; tensile strength, 2.10 × 10⁴ psi; and melting point elevation in excess of 10 K. The levels of property enhancement seem to be bound in their lower limit by a metastable liquid crystalline form. The upper theoretical limit of property enhancement should correspond to a fully extended chain morphology.     

Elongational rheology of fiber forming polymers

The elongational rheology of some fiber forming polymers, such as polypropylene (PP), polyethylene (PE), nylon 66, and lyocell (cellulose dissolved in N-Methylmorpholine/water) solutions, has been characterized using hyperbolic convergent dies in a capillary rheometer, at different Hencky strains, processing temperatures, and as a function of elongational strain rates up to 600 s^{− 1}. The influence of melt flow rate (MFR) and molecular parameters is studied and it is shown that the elongational viscosity curves can be shifted with respect to both temperature and Hencky strain.     

Theoretical investigation of metal-molecule interface with terminal groups

The effects of terminal groups on the electron transport between metal electrodes and molecule are investigated through metal-molecule-metal systems using the first principles method, which is based on the density functional theory, with norm-conserving nonlocal pseudopotentials and nonequilibrium Green's functions. Eight Au-molecule-Au open systems are constructed and numerically examined, where gold atoms are used as electrode, benzene and borazine as core molecules, and sulphur (S), oxygen (O), selenium (Se), and cyano-group (CN) as terminal groups. Gold electrodes are described through a three-dimensional atomic model. The current-voltage (I-V) characteristics, density of states, and transmission functions of constructed systems are calculated and analyzed. Results show that the transmission properties of the systems are affected greatly by the terminal groups and are dependent on the core molecule as well. Se is demonstrated as the best terminal group to couple borazine to Au electrodes and CN is the best one to couple benzene to Au electrodes.