Isolation and characterization at cholinergic nicotinic receptors of a neurotoxin from the venom of the Acanthophis sp Seram death adder

The present study describes the isolation of the first neurotoxin (acantoxin IVa) from Acanthophis sp. Seram death adder venom and an examination of its activity at nicotinic acetylcholine receptor (naChR) subtypes. Acantoxin IVa (MW 6815; 0.1-1.0 muM) caused concentration-dependent inhibition of indirect twitches (0.1 Hz, 0.2 ms, supramaximal V) and inhibited contractile responses to exogenous nicotinic agonists in the chick biventer cervicis nerve-muscle, confirming that this toxin is a postsynaptic neurotoxin. Acantoxin IVa (1-10 nM) caused pseudo-irreversible antagonism at skeletal muscle nAChR with an estimated pA(2) Of 8.36 +/- 0.17. Acantoxin IVa was approximately two-fold less potent than the long-chain (Type 11) neurotoxin, alpha-bungarotoxin. With a pK(i) value of 4.48, acantoxin IVa was approximately 25,000 times less potent than a-bungarotoxin at alpha7-type neuronal nAChR. However, in contrast to alpha-bungarotoxin, acantoxin IVa completely inhibited specific [H-3]-methyllycaconitine (MLA) binding in rat hippocampus homogenate. Acantoxin IVa had no activity at ganglionic nAChR, alpha4beta2 subtype neuronal nAChR or cytisine-resistant [H-3]-epibatidine binding sites. While long-chain neurotoxin resistant [H-3]-MLA binding in hippocampus homogenate requires further investigation, we have shown that a short-chain (Type 1) neurotoxin is capable of fully inhibiting specific [H-3]-MLA binding. (C) 2004 Elsevier Inc. All rights reserved.

Isolation and characterization of microsatellite loci from mother-of-millions, Bryophyllum delagoense (Crassulaceae), and its hybrid with Bryophyllum daigremontianum, 'Houghton's hybrid'

Nine microsatellite loci were developed, and are transferable, across the Madagascan succulents Bryophyllum daigremontianum, Bryophyllum delagoense (mother-of-millions) and their horticultural hybrid (Houghton's), from enriched libraries of the later two species. For B. delagoense, a tetraploid, three to 13 alleles per locus were found for native Madagascan (H-O = 0.4-1.0), and one to nine in invasive Australian (H-O = 0.0-1.0) samples. In addition for 91 Australian samples, only five multilocus genotypes were found (95% of individuals were of two genotypes), suggesting extensive clonality in its introduced range. These loci will be used to examine genetic diversity, hybrid origin and mating system in natural and introduced populations.

The effect of weightbearing exercise with low frequency, whole body vibration on lumbosacral proprioception: A pilot study on normal subjects

Patients with low back pain (LBP) often present with impaired proprioception of the lumbopelvic region. For this reason, proprioception training usually forms part of the rehabilitation protocols. New exercise equipment that produces whole body, low frequency vibration (WBV) has been developed to improve muscle function, and reportedly improves proprioception. The aim of this pilot study was to investigate whether weightbearing exercise given in conjunction with WBV would affect lumbosacral position sense in healthy individuals. For this purpose, twenty-five young individuals with no LBP were assigned randomly to an experimental or control group. The experimental group received WBV for five minutes while holding a static, semi-squat position. The control group adopted the same weightbearing position for equal time but received no vibration. A two-dimensional motion analysis system measured the repositioning accuracy of pelvic tilting in standing. The experimental (WBV) group demonstrated a significant improvement in repositioning accuracy over time (mean 0.78 degrees) representing 39% improvement. It was concluded that WBV may induce improvements in lumbosacral repositioning accuracy when combined with a weightbearing exercise. Future studies with WBV should focus on evaluating its effects with different types of exercise, the exercise time needed for optimal outcomes, and the effects on proprioception deficits in LBP patients.

Rifampicin and sodium fusidate reduces the frequency of methicillin-resistant Staphylococcus aureus (MRSA) isolation in adults with cystic fibrosis and chronic MRSA infection

Nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) to patients with cystic fibrosis (CF) frequently results in chronic respiratory tract carriage. This is an increasing problem, adds to the burden of glycopeptide antibiotic use in hospitals, and represents a relative contraindication to lung transplantation. The aim of this study was to determine whether it is possible to eradicate MRSA with prolonged oral combination antibiotics, and whether this treatment is associated with improved clinical status. Adult CF patients (six mate, one female) with chronic MRSA infection were treated for six months with rifampicin and sodium fusidate. Outcome data were examined for six months before treatment, on treatment and after treatment. The patients had a mean age of 29.3 (standard deviation = 6.3) years and FEV1 of 36.1% (standard deviation = 12.7) predicted. The mean duration of MRSA isolation was 31 months. MRSA isolates identified in these patients was of the same lineage as the known endemic strain at the hospital when assessed by pulsed-field get electrophoresis. Five of the seven had no evidence of MRSA during and for at [east six months after rifampicin and sodium fusidate. The proportion of sputum samples positive for MRSA was lower during the six months of treatment (0.13) and after treatment (0.19) compared with before treatment (0.85) (P < 0.0001). There was a reduction in the number of days of intravenous antibiotics per six months with 20.3 +/- 17.6 on treatment compared with 50.7 before treatment and 33.0 after treatment (P = 0.02). There was no change in lung function. Gastrointestinal side effects occurred in three, but led to therapy cessation in only one patient. Despite the use of antibiotics with anti-staphylococcal activity for treatment of respiratory exacerbation, MRSA infection persists. MRSA can be eradicated from the sputum of patients with CF and chronic MRSA carriage by using rifampicin and sodium fusidate for six months. This finding was associated with a significant reduction in the duration of intravenous antibiotic treatment during therapy. (C) 2003 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

A cognitive genetic algorithm for power distribution system planning

Power systems are large scale nonlinear systems with high complexity. Various optimization techniques and expert systems have been used in power system planning. However, there are always some factors that cannot be quantified, modeled, or even expressed by expert systems. Moreover, such planning problems are often large scale optimization problems. Although computational algorithms that are capable of handling large dimensional problems can be used, the computational costs are still very high. To solve these problems, in this paper, investigation is made to explore the efficiency and effectiveness of combining mathematic algorithms with human intelligence. It had been discovered that humans can join the decision making progresses by cognitive feedback. Based on cognitive feedback and genetic algorithm, a new algorithm called cognitive genetic algorithm is presented. This algorithm can clarify and extract human's cognition. As an important application of this cognitive genetic algorithm, a practical decision method for power distribution system planning is proposed. By using this decision method, the optimal results that satisfy human expertise can be obtained and the limitations of human experts can be minimized in the mean time.

Changes in joint stability with muscle contraction measured from transmission of mechanical vibration

A non-invasive in vivo technique was developed to evaluate changes in wrist joint stability properties induced by increased co-activation of the forearm muscles in a gripping task. Mechanical vibration at 45, 50 and 55 Hz was applied to the radial head in ten healthy volunteers. Vibrations of the styloid process of the radius and the distal end of the metacarpal bone of the index finger were measured with triaxial accelerometers. Joint stability properties were quantified by the transfer function gain between accelerations on either side of the wrist-joint. Gain was calculated with the muscles at rest and at five force levels ranging from 5% to 25% of maximum grip force (%MF). During contraction the gain was significantly greater than in control trial (0%MF) for all contractions levels at 45 and 50 Hz and a trend for 15%MF and higher at 55 Hz. Group means of contraction force and gain were significantly correlated at 45 (R-2 = 0.98) and 50 Hz (R-2 = 0.72), but not at 55 Hz (R-2 = 0.10). In conclusion, vibration transmission gain may provide a method to evaluate changes in joint stability properties. (c) 2005 Published by Elsevier Ltd.

Bright entanglement in the intracavity nonlinear coupler

We show that the intracavity Kerr nonlinear coupler is a potential source of bright continuous variable entangled light beams which are tunable and spatially separated. We use a linearized fluctuation analysis to calculate the necessary correlations in regimes where it is valid. This means that we are treating regimes where the system exhibits Gaussian statistics so that well-known criteria are both necessary and sufficient to demonstrate entanglement. This system may be realized with integrated optics and thus provides a potentially rugged and stable source of bright entangled beams.

Neural Stem cell Isolation and Characterization

Throughout the process of development and continuing into adulthood, stem cells function as a reservoir of undifferentiated cell types, whose role is to underpin cell genesis in a variety of tissues and organs. In the adult, they play an essential homeostatic role by replacing differentiated tissue cells "worn off" by physiological turnover or lost to injury or disease. As such, the discovery of such cells in the adult mammalian central nervous system (CNS), an organ traditionally thought to have little or no regenerative capacity, was most unexpected. Nonetheless, by employing a novel serum-free culture system termed the neurosphere assay, Reynolds and Weiss demonstrated the presence of neural stem cells in both the adult (Reynolds and Weiss, 1992) and embryonic mouse brain (Reynolds et al., 1992). Here we describe how to generate, serially passage, and differentiate neurospheres derived from both the developing and adult brain, and provide more technical details that will enable one to achieve reproducible cultures, which can be passaged over an extended period of time.

Illusory changes in head position induced by neck muscle vibration can alter the perception of elbow position

Acuity for elbow joint position sense (JPS) is reduced when head position is modified. Movement of the head is associated with biomechanical changes in the neck and shoulder musculoskeletal system, which may explain changes in elbow JPS. The present study aimed to determine whether elbow JPS is also influenced by illusory changes in head position. Simultaneous vibration of sternocleidomastoid (SCM) and the contralateral splenius was applied to 14 healthy adult human subjects. Muscle vibration or passive head rotation was introduced between presentation and reproduction of a target elbow position. Ten out of 14 subjects reported illusions consistent with lengthening of the vibrated muscles. In these 10 subjects, absolute error for elbow JPS increased with left SCM/right splenius vibration but not with right SCM/left splenius vibration. Absolute error also increased with right rotation, with a trend for increased error with left rotation. These results demonstrated that both actual and illusory changes in head position are associated with diminished acuity for elbow JPS, suggesting that the influence of head position on upper limb JPS depends, at least partially, on perceived head position.

Construction of an Intraplate Fault System Model of South Australia, and Simulation Tool for the iSERVO Institute Seed Project

To foster ongoing international cooperation beyond ACES (APEC Cooperation for Earthquake Simulation) on the simulation of solid earth phenomena, agreement was reached to work towards establishment of a frontier international research institute for simulating the solid earth: iSERVO = International Solid Earth Research Virtual Observatory institute (http://www.iservo.edu.au). This paper outlines a key Australian contribution towards the iSERVO institute seed project, this is the construction of: (1) a typical intraplate fault system model using practical fault system data of South Australia (i.e., SA interacting fault model), which includes data management and editing, geometrical modeling and mesh generation; and (2) a finite-element based software tool, which is built on our long-term and ongoing effort to develop the R-minimum strategy based finite-element computational algorithm and software tool for modelling three-dimensional nonlinear frictional contact behavior between multiple deformable bodies with the arbitrarily-shaped contact element strategy. A numerical simulation of the SA fault system is carried out using this software tool to demonstrate its capability and our efforts towards seeding the iSERVO Institute.

Influence of imperfect interfaces on bending and vibration of laminated composite shells

This paper is devoted to modeling elastic behavior of laminated composite shells, with special emphasis on incorporating interfacial imperfection. The conditions of imposing traction continuity and displacement jump across each interface are used to model imperfect interfaces. Vanishing transverse shear stresses on two free surfaces of a shell eliminate the need for shear correction factors. A linear theory underlying elastostatics and kinetics of laminated composite shells in a general configuration is presented from Hamilton's principle. In the special case of vanishing interfacial parameters, this theory reduces to the conventional third-order zigzag theory for perfectly bonded laminated shells. Numerical results for bending and vibration problems of laminated circular cylindrical panels are tabulated and plotted to indicate the influence of the interfacial imperfection. (C) 2000 Elsevier Science Ltd. All rights reserved.

The tectonically-confined Firenzuola turbidite system (Miocene, Marnoso-arenacea Formation, northern Apennines, Italy): an example of facies variations related to the basin morphology

The Firenzuola turbidite system formed during a paroxysmal phase of thrust propagation, involving the upper Serravallian deposits of the Marnoso-arenacea Formation (MAF). During this phase the coeval growth of two major tectonic structures, the M. Castellaccio thrust and the Verghereto high, played a key role, causing a closure of the inner basin and a coeval shift of the depocentre to the outer basin. This work focuses on this phase of fragmentation of the MAF basin; it is based on a new detailed high-resolution stratigraphic framework, which was used to determine the timing of growth of the involved structures and their direct influence on sediment dispersal and on the lateral and vertical turbidite facies distribution. The Firenzuola turbidite system stratigraphy is characterized by the occurrence of mass-transport complexes (MTCs) and thick sandstone accumulation in the depocentral area, which passes to finer drape over the structural highs; the differentiation between these two zones increases over time and ends with the deposition of marly units over the structural highs and the emplacement of the Visignano MTC. According to the stratigraphic pattern and turbidite facies characteristics, the Firenzuola System has been split into two phases, namely Firenzuola I and Firenzuola II: the former is quite similar to the underlying deposits, while the latter shows the main fragmentation phase, testifying the progressive isolation of the inner basin and a coeval shift of the depocentre to the outer basin. The final stratigraphic and sedimentological dataset has been used to create a quantitative high-resolution 3D facies distribution using the Petrel software platform. This model allows a detailed analysis of lateral and vertical facies variations that can be exported to several reservoirs settings in hydrocarbon exploration and exploitation areas, since facies distributions and geometries of the reservoir bodies of many sub-surface turbidite basins show a significant relationship to the syndepositional structural activity, but are beyond seismic resolution.

Amplitude response of a unilaterally constrained nonlinear micromechanical resonator

Dynamical systems that involve impacts frequently arise in engineering. This Letter reports a study of such a system at microscale that consists of a nonlinear resonator operating with an unilateral impact. The microresonators were fabricated on silicon-on-insulator wafers by using a one-mask process and then characterised by using the capacitively driving and sensing method. Numerical results concerning the dynamics of this vibro-impact system were verified by the experiments. Bifurcation analysis was used to provide a qualitative scenario of the system steady-state solutions as a function of both the amplitude and the frequency of the external driving sinusoidal voltage. The results show that the amplitude of resonant peak is levelled off owing to the impact effect and that the bandwidth of impacting is dependent upon the nonlinearity and the operating conditions.

Simulation of guiding-centre soliton transmission system stability in the presence of polarisation mode dispersion

Results of full numerical simulations of a guiding-centre soliton system with randomly birefringent SMF fibre are shown and analysed. It emerges that the soliton system becomes unstable even for small amounts of PMD.