Wound healing and the immune response in swine treated with a hemostatic bandage composed of salmon thrombin and fibrinogen

We investigated the inflammatory response in pigs exposed to salmon fibrinogen/thrombin dressings. Animals were exposed to the material in 3 ways: (a) thrombin and fibrinogen were injected intravenously, (b) dual full-thickness skin lesions were surgically created on the dorsal aspect of the swine and treated with the fibrinogen/thrombin bandage and a commercial bandage or (c) a fibrinogen/thrombin bandage was inserted through an abdominal incision into the peritoneal cavity. Blood was collected twice weekly and animals were sacrificed at 7, 10 or 28 days. Animals in the 28-day dermal lesion group were given an injection of salmon fibrinogen/thrombin at the 10 day point to simulate a second bandage application. The immune response manifested itself as induction of germinal centers in mesenteric lymph nodes and in the white pulp of the spleen. Examination of the histology of the skin and organs showed a cellular inflammatory response with granulation tissue and signs of edema that resolved by the 28-day stage. Antibodies reactive to salmon and human thrombin and fibrinogen were detected, but fibrinogen levels and coagulation processes were not affected. In conclusion, animals treated with salmon fibrinogen/thrombin bandages demonstrated a smooth recovery course in terms of both tissue healing and the immune response without adverse effects from the exposure to the fish proteins.     

On the effect of variable endmember spectra in the linear mixture model

The linear mixture model is frequently used to characterize surface cover over land, to model the reflectance of heterogeneous surfaces, and, by inversion, to estimate fractional cover from a multispectral satellite signal. It is usually assumed that certain parameters of this model, namely the so-called endmember spectra, are fixed, and that the model residual - the difference between a signal and its expected value in terms of the linear model - is systematically independent of all other parameters. In a small number of studies the endmember spectra have been allowed to have random fluctuations, giving rise to a covariance matrix for the residual that depends on the underlying proportions, and two distinct models exist for this mixed-pixel covariance matrix. In this note the linear model for mixed pixels is examined with varying endmember spectra, and it is shown that under a simple set of models for the variability of both endmembers and abundance, the covariance matrix for the residual is a weighted sum of the two previously considered cases. Generally, the balance between the two limiting cases is determined by the length scale for changes in the reflectance of any given cover type, and the length scale for changes in surface cover itself; one or other of the two limit models is preferred when these lengths are very different.     

A primate model for enteral nutrition by tube

To establish an animal model for the controlled study of enteral nutrition by tube, five adult chair-adapted primates (Macaca fasicularis) had gastrostomy and jejunostomy tubes placed for the delivery of a modified protein isolate diet. Following 7 days of postoperative depletion with a hypocaloric infusion of dextrose (20 kcal, 0 g N/kg/day), the animals were repleted for 10 days with tube feedings (124 kcal, 0.73 g N/kg/day). There was no operative mortality or morbidity and each animal demonstrated conversion to anabolism by significant weight gain, positive nitrogen balance, and net protein synthesis as determined by [15N]glycine protein turnover rates. Significant correlation was found between caloric intake and nitrogen balance at the level of nitrogen provided in this diet (r = 0.88, p less than 0.05). This model was found to be well suited for the surgical and nutritional techniques required for the long-term study of enteral nutrition by tube.     

The PROBA/CHRIS mission: a low-cost smallsat for hyperspectral multiangle observations of the Earth surface and atmosphere

The European Space Agency's Project for On-Board Autonomy is intended to demonstrate a range of innovations in the design, construction, and operation of small satellites. It carries a number of scientific instruments, the most advanced of which is the Compact High-Resolution Imaging Spectrometer. A typical nadir image is 13 km /spl times/13 km in size and has 18 narrow spectral channels at 17-m spatial resolution. When operated at 34-m spatial resolution, the instrument can capture data in 62, almost contiguous, spectral channels. The platform is highly manoeuvrable: along-track pointing allows a given site to be imaged five times during a single overpass, while across-track pointing ensures that the revisit time for a site of interest is less than a week. This unique combination of spectral and angular sampling provides a rich source of data with which to study environmental processes in the atmosphere and at the Earth's surface.     

Bounding the firing synchronization problem on a ring

In this paper we improve the upper and lower bounds on the complexity of solutions to the firing synchronization problem on a ring. In this variant of the firing synchronization problem the goal is to synchronize a ring of identical finite automata. Initially, all automata are in the same state except for one automaton that is designated as the initiator for the synchronization. The goal is to define the set of states and the transition function for the automata so that all machines enter a special fire state for the first time and simultaneously during the final round of the computation. In our work we present two solutions to the ring firing synchronization problem, an 8-state minimal-time solution and a 6-state non-minimal-time solution. Both solutions use fewer states than the previous best-known minimal-time automaton, a 16-state solution due to Culik. We also give the first lower bounds on the number of states needed for solutions to the ring firing synchronization problem. We show that there is no 3-state solution and no 4-state, symmetric, minimal-time solution for the ring.     

On the relationship between spectral unmixing and subspaceprojection

A linear transformation was recently recommended for application on hyperspectral imagery. This note shows that the method is completely equivalent to extracting proportional ground cover by standard means, but is less efficient than the more usual methods of spectral unmixing     

Prospective study of the risk of Clostridium difficile diarrhoea in elderly patients following treatment with cefotaxime or piperacillin-tazobactam

BACKGROUND: Rates of Clostridium difficile diarrhoea have recently been rising, with the elderly being at highest risk. AIM: To compare the incidence of C. difficile colonization and diarrhoea in elderly patients treated for presumed infection with either empirical cefotaxime (CTX) or piperacillin-tazobactam (PT). METHODS: A prospective, ward-based, crossover study was carried out on two well-matched care of the elderly wards at a UK tertiary care hospital, in patients requiring empirical broad-spectrum antibiotic treatment. RESULTS: There was a highly significant increased incidence of C. difficile colonization (26/34 vs. 3/14, P=0.001) and diarrhoea (18/34 vs. 1/14, P=0.006) in patients who received CTX as opposed to PT. DNA fingerprinting suggested that most infections arose from strains acquired from the hospital environment. CONCLUSIONS: Elderly patients are significantly less likely to develop C. difficile diarrhoea after treatment with PT than after CTX. The source of C. difficile appears to be predominantly from the ward environment.