MLP/RBF neural-networks-based online global model identification of synchronous generator

This paper compares the performances of a multilayer perceptron neural network (MLPN) and a radial basis function neural network (RBFN) for online identification of the nonlinear dynamics of a synchronous generator in a power system. The computational requirement to process the data during the online training, local convergence, and online global convergence properties are investigated by time-domain simulations. The performances of the identifiers as a global model, which are trained at different stable operating conditions, are compared using the actual signals as well as the deviation signals for the inputs of the identifiers. Such an online-trained identifier with fixed optimal weights after the global convergence test is needed to provide information about the plant to a neurocontroller. The use of the fixed weights is to provide against a sensor failure in which case the training of the identifiers would be automatically stopped, and their weights frozen, but the control action, which uses the identifier, would be able to continue.     

Pathways to controlled 3D deformation of graphene: Manipulating the motion of topological defects

Functional properties of 2D materials like graphene can be tailored by designing their 3D structure at the Angstrom to nanometer scale. While there are routes to tailoring 3D structure at larger scales, achieving controllable sub-micron 3D deformations has remained an elusive goal since the original discovery of graphene. In this contribution, we summarize the state-of-the-art in controllable 3D structures, and present our perspective on pathways to realizing atomic-scale control. We propose an approach based on strategic application of mechanical load to precisely relocate and position topological defects that give rise to curvature and corrugation to achieve a desired 3D structure. Realizing this approach requires establishing the detailed nature of defect migration and pathways in response to applied load. From a computational perspective, the key needed advances lie in the identification of defect migration mechanisms. These needed advances define new forward and inverse problems: when a fixed stress or strain field is applied, along which pathways will defects migrate?, and vice versa. We provide a formal statement of these forward and inverse problems, and review recent methods that may enable solving them. The forward problem is addressed by determining the potential energy surface of allowable topological configurations through Monte Carlo and Gaussian process models to determine defect migration paths through dynamic programming algorithms or Monte Carlo tree search. Two inverse models are suggested, one based on genetic algorithms and another on convolutional neural networks, to predict the applied loads that induce migration and position defects to achieve desired curvature and corrugation. The realization of controllable 3D structures enables a vast design space at multiple scales to enable new functionality in flexible electronics, soft robotics, biomimetics, optics, and other application areas.     

Communication between deaf children and their hearing mothers: the role of language, gesture, and vocalizations

In the present longitudinal study, 20 deaf and 20 hearing children were observed during free play with their hearing mothers when the children were 22 months and 3 years of age. Compared to hearing children, deaf children were severely language delayed, with deaf 3-year-olds using less language (speech or sign) than hearing 22-month-olds. Deaf children communicated primarily through nonlinguistic vocalizations, with increasing use of gesture from 22 months to 3 years of age. Although mothers of deaf children used more visual communication than mothers of hearing children, they still primarily communicated through speech. In addition, deaf children did not visually attend to much of their mothers' communication. Therefore, deaf children received much less communication than hearing children. These results suggest that intervention efforts should be focused on increasing the quantity of perceived linguistic input by the child.     

Evaluation of the effectiveness of continuous renal replacement therapy in critical patients after cardiovascular surgery

The efficacy of continuous methods of renal substitute therapy (RST) in patients with multiple organ failure is assessed. The patients were divided in 2 groups administered different types of PST. Group 1 were 16 patients subjected to RST by peritoneal dialysis, in group 2 (n = 16) GP and/or GDP were used. Hemodynamics, hematological and biochemical values, and clearance of inflammation mediators were monitored and hemohydrobalance and complications of therapy assessed in the course of RST. Both RST methods proved to be highly effective. The possibility of differentiated use of peritoneal dialysis and GP/GDP permits an individual approach to treatment, and equally high efficacy of both methods solves the problem of treating total renal insufficiency in the majority of patients with multiple organ failure following cardiovascular surgery.     

Adenosine deaminase in differential diagnosis of peripheral lymph node tuberculosis

Improved hemodynamics and blood flow have been reported in patients with IABPs who experience cardiopulmonary arrest and require CPR. The following research questions, however, remain unanswered: Is there a more effective method of using IABP to prevent cardiac arrest and the need for CPR? Is the timing of balloon inflation and deflation the same for patients undergoing CPR as it is for patients who do not require CPR? Would earlier or later inflation or deflation further enhance cerebral or systemic blood flow? What are the most effective ways for healthcare staff to maintain competency skills in CPR in patients with IABPs?     

Bradykinin increases the proportion of neonatal rat dorsal root ganglion neurons that respond to capsaicin and protons

A number of studies have examined bradykinin-induced sensitization of primary afferent neurons to mechanical or thermal stimuli. However, bradykinin-induced sensitization to other chemical stimuli has not been systematically addressed. We used primary cultures of dorsal root ganglion neurons from neonatal rats to determine whether bradykinin alters the responsiveness of individual neurons to capsaicin and protons. An increase in the concentration of free intracellular Ca2+ was used as a measure of a response to capsaicin or low pH. Pretreatment with bradykinin (30 nM) increased the proportion of "intermediate-size" (240-320 microm2) dorsal root ganglion neurons that responded to capsaicin (100 nM) or low pH (6.1). However, among "small-size" (160-239 microm2) neurons, bradykinin increased the proportion of neurons that responded to low pH (6.1) but not to capsaicin (10 or 100 nM). Because treatment with arachidonic acid (10 microM) did not mimic the effect of bradykinin and inhibition of cyclo-oxygenase and lipoxygenase with 5,8,11,14-eicosatetraynoic acid (10 microM) did not inhibit the effect of bradykinin on the response to capsaicin, it is not likely that the bradykinin-induced enhancement of neuronal responsiveness is mediated by arachidonic acid or its metabolites in this model. These results support the hypothesis that bradykinin sensitizes primary afferent neurons to other chemicals such as protons that are present in inflamed tissue, particularly by recruiting additional sensory neurons to respond to a given chemical stimulus. An increase in the number of responsive nociceptors that innervate inflamed tissue would contribute to hyperalgesia via spatial summation on spinal neurons in the pathway for pain. Furthermore, since bradykinin enhanced the responsiveness of small-size neurons that responded to protons but not to capsaicin, these data suggest that bradykinin-induced sensitization to protons and capsaicin occur by different mechanisms.     

A model of peptide-induced lupus autoimmune B cell epitope spreading is strain specific and is not H-2 restricted in mice

Anti-Sm is a common and specific autoantibody found in systemic lupus erythematosus. The peptide PPPGMRPP from Sm B/B' is an early target of the autoimmune response in some anti-Sm-positive human patients. After immunization with this peptide on a MAP backbone, rabbits develop anti-Sm autoantibodies with B cell epitope spreading of the autoimmune response as well as other features of lupus autoimmunity. Various strains of inbred mice have been immunized with peptide PPPGMRPP or PSQQVMTP (nonantigenic region of Sm B/B') in Freund's adjuvant or with no peptide. All peptide-immunized mouse strains eventually develop high titers of specific anti-peptide of immunization Abs. Mice immunized with Freund's adjuvant alone have no measurable Ab binding to the PPPGMRPP peptide. With time, nearly half the mouse strains tested develop Abs that react with additional regions of Sm B/B' and Sm D. All the regions bound by mouse serum are major epitopes of the human systemic lupus erythematosus anti-Sm response. These same strains also develop significant anti-Sm and anti-nuclear ribonucleoprotein titers. In addition, some of these strains demonstrate positive anti-nuclear Abs and anti-dsDNA Abs. Experiments with congenic H-2 mice demonstrate that the H-2 region does not play a role in spreading the immune response from the peptide of immunization to other epitopes of the spliceosome. These results present a new murine model of B cell epitope spreading and lupus autoimmunity induced by peptide immunization that is strain specific and not apparently dependent upon the loci at H-2.     

Nonrandomness in protein sequences: evidence for a physically driven stage of evolution?

The sequences, or primary structures, of existing biopolymers--in particular, proteins--are believed to be a product of evolution. Are the sequences random? If not, what is the character of this nonrandomness? To explore the statistics of protein sequences, we use the idea of mapping the sequence onto the trajectory of a random walk, originally proposed by Peng et al. [Peng, C.-K., Buldyrev, S. V., Goldberger, A. L., Havlin, S., Sciortino, F., Simons, M. & Stanley, H. E. (1992) Nature (London) 356, 168-170] in their analysis of DNA sequences. Using three different mappings, corresponding to three basic physical interactions between amino acids, we found pronounced deviations from pure randomness, and these deviations seem directed toward minimization of the energy of the three-dimensional structure. We consider this result as evidence for a physically driven stage of evolution.