Temperature controller for a fluid cooled garment

An automatic controller for controlling the inlet temperature of the coolant to a fluid cooled garment without requiring skin sensors is described. Temperature is controlled by the wearer's evaporative water loss rate

A study of surface swelling caused by graphitisation during pulsed laser ablation of carbon allotrope with high content of sp ³ bounds

Experiments and theory are employed to investigate the laser ablation of boron doped diamond and tetrahedral amorphous carbon using nanosecond pulses. For a single pulse at low values of fluence, the laser induces a swelling of the surface due to graphitisation, whilst a high level of fluence leads to recession of the surface due to vaporization. To understand and investigate the underlying phenomena during the diamond-laser interaction, a model has been developed to reliably and quickly predict the behaviour of the surface and the thickness of the heat affected zone. The model is based on conservation of heat and mass during the laser-workpiece interaction. It consists of a one-dimensional system of non-linear equations that models the material heating, evaporation, graphitisation and plasma shielding. There is excellent agreement between numerical and experimental results for the position of the interfaces up to a high laser fluence. This model is the first to investigate the ablation of diamond that is able to capture surface swelling due to the graphitisation of the diamond layer, the graphite thickness and the amount of ablated material within a single framework. Furthermore, the model provides a novel methodology to investigate the thermal stability of diamond-like carbon films. The activation energy for tetrahedral amorphous carbon is obtained using the model with an accuracy of 3.15+1.0−0.22 eV

Stochastic simplified modelling of abrasive waterjet footprints

Abrasive micro-waterjet processing is a non-conventional machining method that can be used to manufacture complex shapes in difficult-to-cut materials. Predicting the effect of the jet on the surface for a given set of machine parameters is a key element of controlling the process. However, the noise of the process is significant, making it difficult to design reliable jet-path strategies that produce good quality parts via controlled-depth milling. The process is highly unstable and has a strong random component that can affect the quality of the workpiece, especially in the case of controlled-depth milling. This study describes a method to predict the variability of the jet footprint for different jet feed speeds. A stochastic partial differential equation is used to describe the etched surface as the jet is moved over it, assuming that the erosion process can be divided into two main components: a deterministic part that corresponds to the average erosion of the jet, and a stochastic part that accounts for the noise generated at different stages of the process. The model predicts the variability of the trench profiles to within<8%. These advances could enable abrasive micro-waterjet technology as a suitable technology for controlled-depth milling

Internal cardiac defibrillation: Histopathology and temporal stability of defibrillation energy requirements

The automatic implantable cardioverter/defibrillator is tested intraoperatively to ensure effectiveness by performing a number of induced fribrillation-defibrillation trials. The temporal stability of defibrillation energy requirements and the histopathologic effects of multiple defibrillating shocks were studied in 12 dogs chronically instrumented with an internal spring-patch lead system identical to that used in humans. Dogs were studied on days 1, 11, 18, 25 and 32. Data were analyzed by logistic regression and the energy required for 50% (E50) and 80% (E80) success was compared. On day 32 the dogs were killed and the heart was removed for gross and microscopic pathologic examination.There was a significant decrease in energy requirements from day 1 to day 11, as the E50decreased from 6.9 ± 4.5 to 4.9 ± 2.5 J (p < 0.02) and the E80decreased from 8.5 ± 5.2 to 6.1 ± 3.4 J (p < 0.02). The energy requirements then remained stable over the remainder of the experiment. The dogs were administered 209 ± 18 shocks (range 1 to 24 J) for a total cumulative dose of 1,524 ± 571 J. In all cases, both grossly and microscopically, there was no evidence of pathologic changes in the myocardium or coronary vessels. In all cases there was a fibrous plaque beneath the patch electrodes, at times containing an area of patchy hemorrhage; in a single specimen a mixed inflammatory infiltrate accompanied the hemorrhage. Endothelialization of the spring electrode with mild right atrial endocardial fibrosis was also observed.Therefore, the energy requirements for successful defibrillation decrease during the first 11 days after testing at implantation, and then remain stable. Also, multiple, closely spaced defibrillating shocks applied through the spring-patch electrode system do not cause myocardial damage or changes other than those associated with the implantation

Homotransplantation of multiple visceral organs

It was technically possible to perform simultaneous homotransplantation of multiple visceral organs including the liver, spleen, pancreas, omentum and the entire gastrointestinal tract. Arterialization of the cooled graft was accomplished through the donor aorta which was removed with the graft and attached to that of the recipient dog. Gastrointestinal hemorrhage after surgery accounted for a high operative mortality and was thought to be due to denervation of the graft. The five dogs which survived the immediate trauma of surgery lived for five and a half to nine days. After the second day, these animals were physically active and able to resume oral alimentation. In three dogs, there was metabolic evidence of rejection of the liver. In two others, jaundice did not develop. These observations were compared with chemical, hematologic and pathologic data obtained in previous experiments involving homotransplantation of the liver alone. In some cases, there was less evidence of host versus graft rejection after the multiple organ transplants. Other data in the present study suggested the possibility that a significant graft versus host reaction may have been an important contributory cause of death. © 1962

The linear inverse problem in energy beam processing with an application to abrasive waterjet machining

The linear inverse problem for energy beam processing, in which a desired etched profile is known and a trajectory of the beam that will create it must be found, is studied in this paper. As an example, abrasive waterjet machining (AWJM) is considered here supported by extensive experimental investigations. The behaviour of this process can be described using a linear model when the angle between the jet and the surface is approximately constant during the process, as occurs for shallow etched profiles. The inverse problem is usually solved by simply controlling dwell time in proportion to the required depth of milling, without considering whether the target surface can actually be etched. To address this, a Fourier analysis Is used to show that high frequency components in the target surface cannot be etched due to the geometry of the jet and the dynamics of the machine. In this paper, this frequency domain analysis is used to improve the choice of the target profile in such a way that it can be etched. The dynamics of the machine also have a large influence on the actual movement of the jet. It is very difficult to describe this effect because the controller of the machine is usually unknown. A simple approximation is used for the choice of the slope of a step profile. The tracking error between the desired trajectory and the real one is reduced and the etched profile is improved. Several experimental tests are presented to show the usefulness of this approach. Finally, the limitations of the linear model are studied

Perioperative donor bone marrow infusion augments chimerism in heart and lung transplant recipients

Background.: We and others have demonstrated that a low level of donor cell chimerism was present for years after transplantation in tissues and peripheral blood of heart and lung recipients; it was associated, in the latter, with a lower incidence of chronic rejection. To augment this phenomenon, we initiated a trial combining simultaneous infusion of donor bone marrow with heart or lung allotransplantation. Methods.: Between September 1993 and January 1995, 15 nonconditioned patients received either heart (n = 10) or lung (n = 5) allografts concurrently with an infusion of unmodified donor bone marrow (3.0 × 108 cells/kg), and were maintained on an immunosuppressive regimen consisting of tacrolimus and steroids. Results.: There was no complication associated with the infusion of donor bone marrow. Chimerism was detectable in 73% of bone marrow-augmented patients up to the last sample tested. Of the 5 control recipients who did not receive bone marrow infusion, only 1 had detectable chimerism by flow on postoperative day 15, which dwindled to an undetectable level by postoperative day 36. None of the patients had evidence of donor-specific immune modulation by mixed lymphocyte reaction. Conclusions.: The combined infusion of donor bone marrow and heart or lung transplantation, without preconditioning of the recipient, is safe and is associated with an augmentation of donor cell chimerism. © 1995 The Society of Thoracic Surgeons

Biscale Chaos in Propagating Fronts

The propagating chemical fronts found in cubic autocatalytic reaction-diffusion processes are studied. Simulations of the reaction-diffusion equation near to and far from the onset of the front instability are performed and the structure and dynamics of chemical fronts are studied. Qualitatively different front dynamics are observed in these two regimes. Close to onset the front dynamics can be characterized by a single length scale and described by the Kuramoto-Sivashinsky equation. Far from onset the front dynamics exhibits two characteristic lengths and cannot be modeled by this amplitude equation. An amplitude equation is proposed for this biscale chaos. The reduction of the cubic autocatalysis reaction-diffusion equation to the Kuramoto-Sivashinsky equation is explicitly carried out. The critical diffusion ratio delta, where the planar front loses its stability to transverse perturbations, is determined and found to be delta=2.300.Comment: Typeset using RevTeX, fig.1 and fig.4 are not available, mpeg simulations are at http://www.chem.utoronto.ca/staff/REK/Videos/front/front.htm

Adoptive transfer of cytomegalovirus-specific CTL to stem cell transplant patients after selection by HLA–peptide tetramers

Stem cell transplantation is used widely in the management of a range of diseases of the hemopoietic system. Patients are immunosuppressed profoundly in the early posttransplant period, and reactivation of cytomegalovirus (CMV) remains a significant cause of morbidity and mortality. Adoptive transfer of donor-derived CMV-specific CD8(+) T cell clones has been shown to reduce the rate of viral reactivation; however, the complexity of this approach severely limits its clinical application. We have purified CMV-specific CD8(+) T cells from the blood of stem cell transplant donors using staining with HLA-peptide tetramers followed by selection with magnetic beads. CMV-specific CD8(+) cells were infused directly into nine patients within 4 h of selection. Median cell dosage was 8.6 x 10(3)/kg with a purity of 98% of all T cells. CMV-specific CD8(+) T cells became detectable in all patients within 10 d of infusion, and TCR clonotype analysis showed persistence of infused cells in two patients studied. CMV viremia was reduced in every case and eight patients cleared the infection, including one patient who had a prolonged history of CMV infection that was refractory to antiviral therapy. This novel approach to adoptive transfer has considerable potential for antigen-specific T cell therapy

European trial of free light chain removal by extended haemodialysis in cast nephropathy (EuLITE): A randomised control trial

<p>Abstract</p> <p>Background</p> <p>Renal failure is a frequent complication of multiple myeloma and when severe is associated with a greatly increased morbidity and mortality. The principal cause of severe renal failure is cast nephropathy, a direct consequence of high concentrations of monoclonal free light chains (FLCs) in patients' sera. FLC removal by extended haemodialysis, using a high cut-off dialyser, has recently been described as a novel therapeutic option.</p> <p>Methods</p> <p>The <b>EU</b>ropean trial of free <b>LI</b>ght chain removal by ex<b>TE</b>nded haemodialysis in cast nephropathy (EuLITE) trial is a prospective, randomised, multicentre, open label clinical trial to investigate the clinical benefits of FLC removal haemodialysis in patients with cast nephropathy, dialysis dependent acute renal failure and <it>de novo </it>multiple myeloma. Recruitment commenced in May 2008. In total, 90 patients will be recruited. Participants will be randomised, centrally, upon enrolment, to either trial chemotherapy and FLC removal haemodialysis or trial chemotherapy and standard high flux haemodialysis. Trial chemotherapy consists of bortezomib, doxorubicin and dexamethasone. FLC removal haemodialysis is undertaken with two Gambro HCO 1100 dialysers in series using an intensive treatment schedule. The primary outcome for the study is independence of dialysis at 3 months. Secondary outcomes are: duration of dialysis, reduction in serum FLC concentrations; myeloma response and survival.</p> <p>Hypothesis</p> <p>FLC removal haemodialysis will increase the rate of renal recovery in patients with severe renal failure secondary to cast nephropathy in <it>de novo </it>multiple myeloma.</p> <p>Trial registration</p> <p>ISRCTN45967602</p