Time-Frequency Coherent Modulation Filtering of Nonstationary Signals

Modulation filtering is a class of techniques for filtering slowly-varying modulation envelopes of frequency subbands of a signal, ideally without affecting the subband signal's temporal fine-structure. Coherent modulation filtering is a potentially more effective type of such techniques where, via an explicit product model, subband envelopes are determined from demodulation of the subband signal with a coherently detected subband carrier. In this paper we propose a coherent modulation filtering technique based on detecting the instantaneous frequency of a subband from its time-frequency representation. We devise theory to show that coherent modulation filtering imposes a new bandlimiting constraint on the product of the modulator and carrier as well as the ability to recover arbitrarily chosen envelopes and carriers from their modulation product. We then formally show that a carrier estimate based on the time-varying spectral center-of-gravity satisfies the bandlimiting condition. This bandwidth constraint leads to effective and artifact-free modulation filters, offering new approaches for potential signal modification. However, the spectral center-of-gravity does not, in general, satisfy the condition of arbitrary carrier recovery. Finally, the results from modulation-filtering a speech signal are then used to validate the theory.     

Adaptive manuals as assistive technology to support and train people with acquired brain injury in their daily life activities

Assistive technologies and ubiquitous computing can be related since both try to help people in their lives. This common objective motivated us to develop and evaluate a system that puts ubiquitous computing technologies into the rehabilitation process of people with acquired brain injury. Thus, in this paper, we present and evaluate a system that shows adaptive manuals for daily-life activities for people with acquired brain injury. This first evaluation allowed us to validate our approach and also to extract valuable information about these systems as well as environmental factors that may affect the patients.     

Development of a factor VIII inhibitor in a newborn haemophiliac

A major problem in the treatment of haemophilia A is the development of inhibitors (antibodies) against factor VIII. We report the case of a newborn male with no family history of haemophilia who developed an intracerebral haemorrhage. On day 10 post-delivery severe haemophilia A was diagnosed and treatment with recombinant FVIII (rFVIII) concentrate was started. Seventy-two hours later the presence of inhibitors was suspected because high doses of rFVIII were required to maintain therapeutic FVIII plasma levels. Days after, the inhibitor was detected. The quick detection of the inhibitor in this newborn haemophiliac allowed us to start the immunotolerance early, without interruption in the administration of rFVIII.     

Lethality of pyrethrins to larvae and postlarvae of the American lobster (Homarus americanus)

Failed spinal anaesthesia for left total hip arthroplasty was followed postoperatively by dense motor paralysis and sensory deficit in the right leg. The patient had received a dose of subcutaneous heparin 1 h before the spinal anaesthetic was attempted. She died of pulmonary embolism on the ninth postoperative day. At autopsy extensive haematomyelia was found in relation to the needle track.     

Safely increasing the proportion of patients with community-acquired pneumonia treated as outpatients: an interventional trial

In 10 patients who underwent transjugular intrahepatic portosystemic shunt (TIPS) at our institution, postoperative pulmonary and systemic hemodynamic changes were compared with those before the procedure. After TIPS, right atrial and pulmonary capillary wedge pressures, cardiac output, and cardiac index increased significantly, and there was a significant decrease in total peripheral resistance. Thus, systemic hemodynamic changes showed evidence of a more hyperdynamic circulation. In addition, right ventricular end-diastolic volume index was significantly increased and this increase was persistent, with maintained right heart strain. With respect to pulmonary hemodynamics, alveolar arterial oxygen difference and right-to-left shunt increased significantly, along with a significant decrease in arterio-venous oxygen content difference, which indicated impairment of pulmonary diffusing capacity. These findings suggest that preoperative evaluation of the cardiac reserve and pulmonary function is important before performing TIPS. After TIPS, patients should be followed carefully because postoperative heart failure or pulmonary edema may occur.     

Preliminary technique of laparoscopic extraperitoneal infrarenal paraaortic lymphadenectomy in the porcine model

The prevalence of Parkinson's disease (PD) is higher in whites than in nonwhites and it increases with advancing age. The pathological hallmarks of PD are loss of pigmented neurons in the substantia nigra pars compacta (SNpc) and presence of Lewy bodies. With increasing age, a similar loss of pigmented neurons in the SNpc has been reported. Hence, age and race possibly play a role in the pathogenesis of PD. The objectives of this study were to count the number of melanized neurons in the SNpc in normal human brains from India and study the change in neuronal count with advancing age and to compare the neuronal counts from this Indian population with counts reported in normal brains from the United Kingdom. Melanized neurons in the SNpc were counted in 84 normal human brains (age range, 5-84 years) in a single 7-microm section at the level of emergence of the oculomotor nerve. In the brains from India, there was no loss of melanized nigral neurons with advancing age. The absolute number of these melanized neurons was about 40% lower than the brains from UK. Despite a low number of melanized nigral neurons in the brains from India, individuals function normally and have dopamine levels comparable with their Western counterparts, suggesting that it is not the absolute number of melanized nigral neurons but the percent loss of nigral neurons that results in dopaminergic deficiency in PD. There is no significant loss of pigmented nigral neurons with age, suggesting that the loss seen in PD is exclusively due to the disease process itself. Indians have a lower prevalence of PD despite having a low count of melanized nigral neurons, suggesting that better protective mechanisms may be present in the Indians to prevent the loss of nigral neurons.     

Shortest Path Problems on a Polyhedral Surface

We describe algorithms to compute edge sequences, a shortest path map, and the Fréchet distance for a convex polyhedral surface. Distances on the surface are measured by the length of a Euclidean shortest path. We describe how the star unfolding changes as a source point slides continuously along an edge of the convex polyhedral surface. We describe alternative algorithms to the edge sequence algorithm of Agarwal et al. (SIAM J. Comput. 26(6):1689–1713, 1997) for a convex polyhedral surface. Our approach uses persistent trees, star unfoldings, and kinetic Voronoi diagrams. We also show that the core of the star unfolding can overlap itself when the polyhedral surface is non-convex.     

Incorporating genome-wide DNA sequence information into a dynamic whole-cell model of Escherichia coli: application to DNA replication

The advent of thousands of annotated genomes, detailed metabolic reconstructions and databases within the flourishing field of systems biology necessitates the development of functionally complete computer models of whole cells and cellular systems. Such models would realistically describe fundamental properties of living systems such as growth, division and chromosome replication. This will inevitably bridge bioinformatic technologies with ongoing mathematical modelling efforts and would allow for in silico prediction of important dynamic physiological events. To demonstrate a potential for the anticipated merger of bioinformatic genome-wide data with a whole-cell computer model, the authors present here an updated version of a dynamic model of Escherichia coli, including a module that correctly describes the initiation and control of DNA replication by nucleoprotein DnaA-ATP molecules. Specifically, a rigorous mathematical approach used to explicitly include the genome-wide distribution of DnaA-binding sites on the replicating chromosome into a computer model of a bacterial cell is discussed. A new simple deterministic approximation of the complex stochastic process of DNA replication initiation is also provided. It is shown for the first time that reasonable assumptions about the mechanism of DNA replication initiation can be implemented in a deterministic whole-cell model to make predictions about the timing of chromosome replication. Furthermore, it is proposed that a large increase in the concentration of DnaA-binding boxes will result in a decreased steady-state growth rate in E. coli.