bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heart Rate Variability (HRV): Sleep Disordered Breathing
Authors: Nazeran Homer , Pamula Yvonne , Behbehani Khosrow 
Published: April 2006

AbstractSleep‐related breathing disorders are a common but often underdiagnosed condition both in adults and in children. It is now evident that abnormal ventilation during sleep can cause a range of adverse physiological sequela including autonomic dysfunction. Extensive research effort over the past two decades has demonstrated that patterns of cyclic variation in the heart rate (HR) or heart rate variability (HRV) are closely linked to partial reduction or complete cessation of airflow during abnormal breathing events (hypopnea or apnea) during sleep. These efforts culminated in the year 2000, when Thomas Penzel from the Hospital of Phillips‐University in Germany and George Moody from MIT, with their collaborators, coordinated a global competition to stimulate rapid research advances in deploying the HRV signal to detect sleep apnea (Computers in Cardiology Apnea Challenge, 2000).The outcome of these efforts have motivated a number of prominent international research groups to use advanced signal processing methods to analyze the HRV signal and to develop dedicated instrumentation or software packages with the objective to detect sleep disordered breathing in symptomatic subjects at an early stage. A comprehensive review of the literature in this field reveals the value, reliability, sensitivity, specificity, and limitations of these methods and devices. Even though the ultimate goal of simplified diagnosis of sleep disordered breathing from HRV signal analysis is not fully realized yet, it is clearly established that the HRV signal carries a wealth of measures that are sensitive to sleep stages, sleep disordered breathing (SDB), and other disorders influencing the cardiovascular system. Thus, careful analysis of the readily accessible electrocardiogram (ECG) and its derived HRV signal, along with new and sophisticated nonlinear signal analysis methods provide the exciting promise that accurate separation of sleep stages and reliable detection of SDB as well as other disorders influencing the autonomic control of the heart is within reach.In this chapter, we first present a simplified and distilled overview of regulation of the HR by the autonomic nervous system (ANS), sleep physiology, and pathophysiology in children and adults. This is followed by a brief review of the HRV signal derivation and processing methods applicable to its analysis for detection of SDB. We conclude the chapter with an example graphical user interface and consider some issues associated with development of integrated software packages to facilitate the simplified detection of SDB from HRV signals.
Gait Retraining After Neurological Disorders
Authors: Lünenburger Lars , Lam Tania , Riener Robert , Colombo Gery 
Published: April 2006

AbstractNeurological disorders like traumatic brain injury, stroke, and spinal cord injury often adversely affect a person's ability to walk. Restoration of gait function is an important goal in the rehabilitation of these patients. Appropriate motor training can facilitate adaptations in the nervous system to recover function after an injury. Important aspects of motor training include task‐specific performance and repetition of the affected movement. This means that to improve walking, the patient must walk. Body‐weight supported treadmill training is becoming increasingly accepted as a valuable strategy for gait rehabilitation after neurological injury. Treadmills that run at slow locomotor speeds allow patients who are partially unloaded from their body weight to walk, possibly with manual assistance by one or more therapists. However, manual therapy is limited in terms of duration, repeatability, and quantification. Robotic devices allow longer training sessions with better support and control of the leg movements. Current developments are directed to patient‐cooperative strategies, which allow the robotic device to adapt to the patient's needs and efforts. Furthermore, proper design of these devices leaves open many possibilities for a repertoire of additional assessment tools that measure patients’ performance during training and other clinical parameters. Future directions in this field include combining robotic devices with functional electrical stimulation and the development of robotic orthoses for retraining overground walking.
Hybrid Solar Cells from Regioregular Polythiophene and ZnO Nanoparticles
Authors: Beek W. J. E. , Wienk M. M. , Janssen R. A. J. 
Published: April 2006

AbstractBlends of nanocrystalline zinc oxide nanoparticles (nc‐ZnO) and regioregular poly(3‐hexylthiophene) (P3HT) processed from solution have been used to construct hybrid polymer–metal oxide bulk‐heterojunction solar cells. Thermal annealing of the spin‐cast films significantly improves the solar‐energy conversion efficiency of these hybrid solar cells to ∼ 0.9 %. Photoluminescence and photoinduced absorption spectroscopy demonstrate that charge‐carrier generation is not quantitative, because a fraction of P3HT appears not to be in contact with or in close proximity to ZnO. The coarse morphology of the films, also identified by tapping‐mode atomic force microscopy, likely limits the device performance.
Structure and Electrical Properties of Ni Nanowire/Multiwalled‐Carbon Nanotube/Amorphous Carbon Nanotube Heterojunctions
Authors: Luo J. , Xing Y. J. , Zhu J. , Yu D. P. , Zhao Y. G. , Zhang L. , Fang H. , Huang Z. P. , Xu J. 
Published: April 2006

AbstractA one‐dimensional heterojunction is fabricated and characterized. This heterojunction comprises a Ni nanowire, a multiwalled carbon nanotube (MWCNT), and an amorphous carbon nanotube (a‐CNT). The three components are in an end‐to‐end configuration, and form two MWCNT contacts, namely a Ni/MWCNT and an MWCNT/a‐CNT contact. The interfacial structures of the two contacts show that multiple outer walls in the MWCNT simultaneously contact the Ni nanowire and the a‐CNT, and can simultaneously participate in electrical transport. By investigating the electrical‐transport properties of the heterojunctions, the two contacts to the MWCNT in every heterojunction are found to behave as two diodes connected in series face‐to‐face, at least one of which exhibits the characteristics of a nearly ideal Schottky diode and obeys thermionic‐emission theory, wherein only the image force lowers the Schottky barrier. The appearance of this type of nearly ideal diode is attributed to the good contacts to the multiple outer walls of the MWCNTs realized by the heterojunctions' structures.
Molecular Materials by Self‐Assembly of Porphyrins, Phthalocyanines, and Perylenes
Authors: Elemans J. A. A. W. , van Hameren R. , Nolte R. J. M. , Rowan A. E. 
Published: April 2006

AbstractPorphyrins, phthalocyanines, and perylenes are compounds with great potential for serving as components of molecular materials that possess unique electronic, magnetic and photophysical properties. In general, a highly specific communication between a large number of these chromophores is required in order to express their function to a maximal level, and for this reason it is of importance to construct arrays in which the molecules are organized in well‐defined geometries with respect to their neighbors. This review is an account of some recent efforts to construct highly ordered assemblies of porphyrins, phthalocyanines, and perylenes by means of self‐assembly in solution and on surfaces, and by attaching them to polymeric scaffolds.
Approximate dynamic programming: Application to process supply chain management
Authors: Choi Jaein , Realff Matthew J. , Lee Jay H. 
Published: April 2006

AbstractMany continuous process industries are required to operate multiproduct supply chains under significant uncertainty in market demands and prices, and mathematical programming formulations have been developed for the deterministic version of the problem. However, available extensions to the stochastic case cannot be readily used to obtain an optimal operating policy in practice because the uncertainty results in an explosion of the scenarios to be considered over an extended time horizon. In this article we represent the uncertainty through Markov chains and use an approach based on stochastic dynamic programming (DP), which can generate a dynamic operating policy that incorporates information about the uncertainty in the problem at each time step. DP is computationally infeasible because of the size of the state and action space for realistic problems. We propose a novel stochastic optimization algorithmic framework called “DP in a heuristically restricted state space.” The confined state space is generated by simulating various potential scenarios under centralized dynamic inventory and production policy generated by combining static local inventory policy heuristics. The resulting DP policy responds to the time‐varying demand for products by appropriately stitching together decisions made by the local static policies. This is a new formulation for effectively combining heuristic policies. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Uncertainty analysis on the righthand side for MILP problems
Authors: Jia Zhenya , Ierapetritou Marianthi G. 
Published: April 2006

AbstractA systematic framework is developed to solve the parametric mixed integer linear programming (pMILP) problems where uncertain parameters are present on the righthand side (RHS) of the constraints. For the case of multiple uncertain parameters, a new algorithm of multiparametric linear programming (mpLP) is proposed, which solves a number of nonlinear problems (NLP) iteratively. At each iteration, a point at which the objective value cannot be represented by the current optimal functions is found, and the new optimal function is included in the next iteration. Given the range of uncertain parameters in a MILP problem, the output of this proposed framework is a set of optimal integer solutions and their corresponding critical regions and optimal functions. A number of examples are presented to illustrate the applicabilities of the proposed approach and comparison with existing techniques. © 2006 American Institute of Chemical Engineers AIChE J, 2006
In vivo activation of SMN in spinal muscular atrophy carriers and patients treated with valproate
Authors: Brichta Lars , Holker Irmgard , Haug Karsten , Klockgether Thomas , Wirth Brunhilde 
Published: April 2006

AbstractObjectiveSpinal muscular atrophy results from loss of the survival motor neuron 1 (SMN1) gene and malfunction of the remaining SMN2. We investigated whether valproic acid can elevate human SMN expression in vivo.MethodsBlood was collected from 10 spinal muscular atrophy carriers and 20 spinal muscular atrophy patients treated with valproic acid.ResultsSeven of 10 carriers demonstrated increased SMN messenger RNA and protein levels. SMN2 messenger RNA levels were elevated in 7 patients and unchanged or decreased in 13 patients.InterpretationWe provide first proof of the in vivo activation of a causative gene by valproic acid in an inherited disease and discuss strategies of monitoring drug response in patients.
Embryotoxicity of oral administered chlorothalonil in mice
Authors: Farag Amina T. , Karkour Tarek Abdel‐Zaher , Okazy Ahmed El 
Published: April 2006

AbstractBACKGROUND: Chlorothalonil (2,4,5,6‐tetrachloroisophthalonitril), the nephrotoxic fungicide, was examined for its potential to produce developmental toxicity in mice after oral administration. METHODS: Pregnant ICR (CD‐1) mice were given sublethal doses of 0 (corn oil), 100, 400, and 600 mg/kg/day chlorothalonil by gavage on gestation days (GD) 6–15. RESULTS: Maternal effects in 400 and 600 mg/kg/day dose groups included signs of toxicity such as weakness and depression in the maternal activity, and reduction in body weight and weight gain. No maternal toxicity was apparent in the 100 mg/kg/day dose group. Maternal exposure to chlorothalonil during organogenesis significantly affected the number of live fetuses, early resorption, and mean fetal weight in the 400 and 600 mg/kg/day dose groups. No external, visceral, and skeletal abnormalities were observed among any of the treated groups compared to the control. CONCLUSIONS: On the basis of the present results chlorothalonil can produce clinical signs of toxicity and fetotoxicity without teratogenic effects at 400 and 600 mg/kg/day dose groups. Birth Defects Research (Part B) 77:104–109, 2006. © 2006 Wiley‐Liss, Inc.
The influence of continuous exposure to 50 Hz electric field on nerve regeneration in a rat peroneal nerve crush injury model
Authors: Aydin Mustafa Asim , Comlekci Selcuk , Ozguner Meltem , Cesur Gokhan , Nasir Serdar , Aydin Zeynep Dilek 
Published: April 2006

AbstractThe effect of power frequency electric field (EF) on nerve regeneration was investigated on a rat peroneal nerve crush injury model. The animals were assigned to three groups: 50 Hz EF and Static EF groups were exposed at 10 kV/m. The sham group was kept in the same setting without any EF applications. EF was uninterruptedly applied for 21 days postoperatively. Repeated measures analysis of daily walking tracks during EF exposure demonstrated lower toe spread recovery (TSR) in the 50 Hz EF group. Significant difference across the groups was found only at days 7, 8, 12, 16, 17, 20, and 21 when TSR was analyzed for each measurement time. Print length recovery and peroneal function index did not differ across the groups. Walking track parameters were found to recover to their baseline values by day 28 in all groups. Day 14 but not day 21 measurements revealed smaller nerve cross‐sectional area, lower total regenerating axon area, and higher mean myelin debris area in 50 Hz EF group. Both day 14 and 21 measurements revealed higher total myelin debris area, lower EDL muscle weight, and lack of significant enlargement in nerve cross‐section distal to the injury, compared to the normal counterpart in 50 Hz EF group. All differences were in keeping with lower rates of Wallerian degeneration and nerve regeneration in 50 Hz EF group. When walking track, histomorphometry and muscle weight are considered individually, their differences across the groups may appear to be subtle to derive a conclusion for a 50 Hz EF effect. However, their concordance with each other in direction of effect suggests that continuous 50 Hz EF exposure has a weak effect that is detrimental mostly to the rate of early nerve regeneration in this axonotmetic injury model. Recovery of walking tracks was not different between Static EF and Sham groups. This suggests that the surface charges that may indirectly affect walking behaviors of the rats, do not account for the lower recovery of TSR in 50 Hz EF group. Differences in nerve regeneration between 50 Hz EF and Static EF groups suggests that electric induction may be required for pure EF effects even though the estimated density of induced fields is not above the endogenous background level for the 50 Hz EF exposure in this study. Bioelectromagnetics 27:401–413, 2006. © 2006 Wiley‐Liss, Inc.
Exposure to AC and DC magnetic fields induces changes in 5‐HT1B receptor binding parameters in rat brain membranes
Authors: Espinosa José Manuel , Liberti Micaela , Lagroye Isabelle , Veyret Bernard 
Published: April 2006

AbstractThe binding properties of the G‐protein coupled receptor (GPCR) serotonin 5‐HT1B receptor were studied under exposure to AC (50 and 400 Hz) and DC magnetic fields (MF) in rat brain membranes. This was an attempt at replicating the positive findings of Massot et al. In saturation experiments using [3H]5‐HT, 1‐h exposures at 1.1 mTrms 50 Hz caused statistically significant increases in both the KD and Bmax binding parameters, from 1.74 ± 0.3 to 4.51 ± 0.86 nM and from 1428 ± 205 to 2137 ± 399 CPM, respectively, in good agreement with previous results. Exposure of the membranes at 400 Hz 0.675 mTrms did not elicit a larger increase in KD in spite of a much larger induced current density. DC fields (1.1 and 11 mT) had a lesser effect compared to AC fields at low values of KDsham, but decreased the affinity at higher values of KDsham. Modeling of the receptor‐ligand‐G protein interactions using the extended ternary complex model yielded good fits for all our data and that of Massot et al., showing that the AC field may act by decreasing the ability of the G‐protein to alter the ligand‐receptor affinity. The hypothesis is that the bipolar nature of the AC field explains the different nature of the effects observed with AC and DC exposures. These findings constitute one of the few documented pieces of evidence for cell‐free effects of DC and extremely low frequency (ELF) AC MFs in the mT range. Bioelectromagnetics 27:414–422, 2006. © 2006 Wiley‐Liss, Inc.
Transient performance of two‐phase partitioning bioreactors treating a toluene contaminated gas stream
Authors: Boudreau Neal G. , Daugulis Andrew J. 
Published: April 2006

AbstractTwo‐phase partitioning bioreactors (TPPBs) consist of a cell‐containing aqueous phase and an immiscible organic phase that sequesters and delivers toxic substrates to cells based on equilibrium partitioning. The immiscible organic phase, which acts as a buffer for inhibitory substrate loadings, makes it possible for TPPBs to handle high volatile organic compound (VOC) loadings, and in this study the performance of liquid n‐hexadecane and solid styrene butadiene (SB) polymer beads used as partitioning phases were compared to a single aqueous phase system while treating transient loadings of a toluene contaminated air stream by Achromobacter xylosoxidans Y234. The TPPBs operated as well‐mixed stirred tanks, with total working volumes of 3 L (3 L aqueous for the single‐phase system, 2 L aqueous and 1 L n‐hexadecane for the solvent system, and 2.518 L aqueous volume and 500 g of SB beads for the polymer system). Two 60‐min step changes (7 and 17 times the nominal loading rates, termed “small” and “large” steps, respectively) were imposed on the systems and the performance was characterized by the overall removal efficiencies, instantaneous removal efficiency recovery times (above 95% removal), and dissolved oxygen recovery times. For the small steps, with a nominal loading of 343 g/m3/h increasing to 2,400 g/m3/h, the TPPB system using n‐hexadecane as the second phase performed best, removing 97% of the toluene fed to the system compared with 90% for the polymer beads system and only 69% for the single‐phase system. The imposed large transient gave similar results, although the impact of the presence of a second sequestering phase was more pronounced, with the n‐hexadecane system maintaining much reduced aqueous toluene concentrations leading to significantly improved performance. This investigation also showed that the presence of both n‐hexadecane and SB beads improved the oxygen transfer within the systems. © 2006 Wiley Periodicals, Inc.
Isolation and analysis of a baculovirus vector that supports recombinant glycoprotein sialylation by SfSWT‐1 cells cultured in serum‐free medium
Authors: Hill Daniel R. , Aumiller Jared J. , Shi Xianzong , Jarvis Donald L. 
Published: April 2006

AbstractThe inability to sialylate recombinant glycoproteins is a critical limitation of the baculovirus‐insect cell expression system. This limitation is due, at least in part, to the absence of detectable sialyltransferase activities and CMP‐sialic acids in the insect cell lines routinely used as hosts in this system. SfSWT‐1 is a transgenic insect cell line encoding five mammalian glycosyltransferases, including sialyltransferases, which can contribute to sialylation of recombinant glycoproteins expressed by baculovirus vectors. However, sialylation of recombinant glycoproteins requires culturing SfSWT‐1 cells in the presence of fetal bovine serum or another exogenous source of sialic acid. To eliminate this requirement and extend the utility of SfSWT‐1 cells, we have isolated a new baculovirus vector, AcSWT‐7B, designed to express two mammalian enzymes that can convertN‐acetylmannosamine to CMP‐sialic acid during the early phase of infection. AcSWT‐7B was also designed to express a model recombinant glycoprotein during the very late phase of infection. Characterization of this new baculovirus vector showed that it induced high levels of intracellular CMP‐sialic acid and sialylation of the recombinantN‐glycoprotein upon infection of SfSWT‐1 cells cultured in serum‐free medium supplemented withN‐acetylmannosamine. In addition, co‐infection of SfSWT‐1 cells with AcSWT‐7B plus a conventional baculovirus vector encoding human tissue plasminogen activator resulted in sialylation of this recombinantN‐glycoprotein under the same culture conditions. These results demonstrate that AcSWT‐7B can be used in two different ways to support recombinantN‐glycoprotein sialylation by SfSWT‐1 cells in serum‐free medium. Thus, AcSWT‐7B can be used to extend the utility of this previously described transgenic insect cell line for recombinant sialoglycoprotein production. © 2006 Wiley Periodicals, Inc.
Assembly of Nanotubes of Poly(4‐vinylpyridine) and Poly(acrylic acid) through Hydrogen Bonding
Authors: Tian Ying , He Qiang , Cui Yue , Tao Cheng , Li Junbai 
Published: April 2006

AbstractNanotubes of poly(4‐vinylpyridine) (PVP) and poly(acrylic acid) (PAA) were fabricated by hydrogen bonding based on layer‐by‐layer (LbL) assembly. The uniform and flexible tubular structures were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). FTIR and X‐ray photoelectron spectroscopy (XPS) measurements confirm the formation of hydrogen bonds in the assembled nanotubes. PAA can be released from the assembled PAA/PVP nanotubes in a basic aqueous solution to give the walls of the tubes a porous structure. Such assembled nanotubes can be considered as carriers for catalysts or drugs, especially in aqueous solution against capillary force.