Three-dimensional computer model of the heart: fibrillation induced by extrastimulation

We present a three-dimensional (3D) computer model that simulates electrical activity in the heart during fibrillation. A real dog heart is discretized to form 1473 interconnected cubic elements. The model exhibits normal activation and recovery from pacing. Five or more extrastimuli induce a self-sustaining tachyarrhythmia that soon degenerates into a fibrillatory rhythm. The extrastimuli increase the excitability of the myocardial cell population. The result is a rapid re-excitation of cells that allows for only a partial recovery of cell action potential. This suggests that a dispersion of refractory states of the cell population is the cause of fibrillation in this computer model.     

Arginine infusion stimulates prolactin, growth hormone, insulin, and subsequent lactation in pregnant dairy cows

L-Arginine or saline was administered intravenously by rapid infusion into 16 late-pregnant Holstein cows to study changes of prolactin, growth hormone, insulin, total protein, urea nitrogen, and subsequent lactation. Arginine was infused daily at .1 g/kg body weight starting about 7 days prior to predicted calving until calving. Blood was sampled via a jugular cannula at 0700, 0715, 0730 (infusion immediately followed 0730 h sample), 0745, 0815, 0845, 1100, 1300, 1500, 1700, and 1900 h. Arginine infusion evoked dramatic but transient increase of concentrations of blood serum prolactin, growth hormone, and insulin. Urea nitrogen also was elevated in blood serum but not total protein. The secretory response of prolactin, growth hormone, and insulin to daily arginine infusion during the entire prepartum period was not diminished. Milk production for the first 22 wk of lactation tended to be higher (by about 10%) for cows infused with arginine as compared to cows infused with saline. Therefore, repeated arginine infusion in late-pregnant cows dramatically increased prolactin, growth hormone, and insulin and tended to increase subsequent milk yield.     

Expression of alpha-D-mannosidase in man-hamster somatic cell hybrids

Two types of alpha-D-mannosidase isozymes are present in human white blood cells, human diploid fibroblasts, and HeLa cells. One of these (the S isozyme) constitutes the major alpha-D-mannosidase of the human cells, has a pH optimum of 4.4, and is associated with lysosomes. The other (the F isozyme) is most active at pH 6, is acid labile, and is located in the soluble portion of the cytoplasm. The expression of human lysosomal alpha-D-mannosidase was examined in man-hamster hybrid clones, and was found to be concordant with that of phosphohexose isomerase in 54 of 55 primary clones. A locus specifying human lysosomal alpha-D-mannosidase has therfore been assigned to chromosome 19.     

对"奇观"文化的质疑

“奇观,是现代被动文化帝国中永不哀落的太阳。”——盖·德波(Guy Debord)今天,在各种文化实践中,对表象的受干扰的观看已经取代深层的阅读。它被媒体所煽动,把现实的表象作为奇观展示出来。奇观文化,与当代信息的泛滥横流相关：它使人崇拜新奇,要求不断产生新的形像以供消费。媒体所需求的形像,可以即刻、虚拟、顺利地四处流通。     

Wireless Emergency Alert messages: Influences on protective action behaviour

The Wireless Emergency Alert (WEA) system delivers text‐based alert and warning messages to notify citizens of imminent, local disaster threats and recommended actions. Although this is a promising new practice in emergency communication, research about how people respond immediately after receiving these messages in real time is sparse. Using a mixed‐methods approach, this study addresses this gap by assessing people's reactivity to WEA messages using experimental simulations of an active shooter and an explosion on a college campus. Only about one in five message recipients took immediate protective action. Quantitative analyses and qualitative interviews suggest individual, message, and situational factors influenced protective action behaviour. These findings inform recommendations to create effective WEA and other text‐based alert and warning messages.     

A genetic animal model of human neocortical heterotopia associated with seizures

Malformations of the human neocortex are commonly associated with developmental delays, mental retardation, and epilepsy. This study describes a novel neurologically mutant rat exhibiting a forebrain anomaly resembling the human neuronal migration disorder of double cortex. This mutant displays a telencephalic internal structural heterotopia (tish) that is inherited in an autosomal recessive manner. The bilateral heterotopia is prominent below the frontal and parietal neocortices but is rarely observed in temporal neocortex. Neurons in the heterotopia exhibit neocortical-like morphologies and send typical projections to subcortical sites; however, characteristic lamination and radial orientation are disturbed in the heterotopia. The period of neurogenesis during which cells in the heterotopia are generated is the same as in the normotopic neocortex; however, the cells in the heterotopia exhibit a "rim-to-core" neurogenetic pattern rather than the characteristic "inside-out" pattern observed in normotopic neocortex. Similar to the human syndrome of double cortex, some of the animals with the tish phenotype exhibit spontaneous recurrent electrographic and behavioral seizures. The tish rat is a unique neurological mutant that shares several features with a human cortical malformation associated with epilepsy. On the basis of its regional connectivity, histological composition, and period of neurogenesis, the heterotopic region in the tish rat is neocortical in nature. This neurological mutant represents a novel model system for investigating mechanisms of aberrant neocortical development and is likely to provide insights into the cellular and molecular events contributing to seizure development in dysplastic neocortex.     

Topical papaverine and facial nerve dysfunction in cerebellopontine angle surgery

We retrospectively investigated the predictive value of lymphocyte subset changes in the peripheral blood of 37 consecutive liver transplant recipients for rejection and infection, both bacterial and cytomegalovirus, during a period of 2 years. Total lymphocyte count correlated with biopsy-proven rejection. There was moderate elevation of CD16+ count during the course of bacterial infection.     

Bubble-sensing: Binding sensing tasks to the physical world

We propose bubble-sensing, a new sensor network abstraction that allows mobile phone users to create a binding between sensing tasks and the physical world at locations of interest, that remains active for a duration set by the user. We envision mobile phones being able to affix sensing task bubbles at places of interest and then receive sensed data as it becomes available in a delay-tolerant fashion, in essence, creating a living documentary of places of interest in the physical world. The system relies on other mobile phones that opportunistically pass through bubble-sensing locations to acquire tasks and do the sensing on behalf of the initiator, and deliver the data to the bubble-sensing server for retrieval by the user who initiated the task.We describe an implementation of the bubble-sensing system using sensor-enabled mobile phones, specifically, Nokia’s N80 and N95 (with GPS, accelerometers, microphone, camera). Task bubbles are maintained at locations through the interaction of “bubble carriers”, which carry the sensing task into the area of interest, and “bubble anchors”, which maintain the task bubble in the area when the bubble carrier is no longer present. In our implementation, bubble carriers and bubble anchors implement a number of simple mobile phone based protocols that refresh the task bubble state as new mobile phones move through the area. Phones communicate using the local Ad-Hoc 802.11g radio to transfer task state and maintain the task in the region of interest. This task bubble state is ephemeral and times out when no bubble carriers or bubble anchors are in the area. Our design is resilient to periods when no mobiles pass through the bubble area and is capable of “reloading” the task into the bubble region. In this paper, we describe the bubble-sensing system and a simple proof-of-concept experiment.     

Psychopathology and sociometric choice.

Previous research has suggested that, except for paranoid schizophrenics, similarity in diagnostic category has little effect on sociometric choice among patients. A sociometric study was conducted employing MMPI scales as well as diagnostic categories on 84 hospitalized psychiatric patients. When diagnostic labels from the patients' charts were used, results showed no relationship between sociometric choice and diagnosis. However, patients classified by highest MMPI scale or by MMPI code type made positive sociometric choices among themselves. (PsycINFO Database Record (c) 2010 APA, all rights reserved)