Periodic orbits: a new language for neuronal dynamics

A new nonlinear dynamical analysis is applied to complex behavior from neuronal systems. The conceptual foundation of this analysis is the abstraction of observed neuronal activities into a dynamical landscape characterized by a hierarchy of "unstable periodic orbits" (UPOs). UPOs are rigorously identified in data sets representative of three different levels of organization in mammalian brain. An analysis based on UPOs affords a novel alternative method of decoding, predicting, and controlling these neuronal systems.     

The incidence of drug-related problems as a cause of hospital admissions in children

OBJECTIVES: To determine the incidence of hospital admissions for drug-related problems (DRPs) among children, and to examine cases for causality, preventability and clinical severity. DESIGN: Prospective assessment involving review of case notes and parent interview to determine if an admission was associated with a DRP. PATIENTS AND SETTING: All patients admitted to a large university-affiliated paediatric hospital in Melbourne, Victoria, for medical reasons (i.e., not surgical, trauma or oncology patients) during 56 consecutive days from 24 June to 19 August 1996 for which a DRP could be identified. Patients whose parents or guardians could not communicate adequately in English were excluded. MAIN OUTCOME MEASURES: The incidence, type, causality, preventability and clinical severity of DRPs associated with admission. RESULTS: Of 1682 eligible patients admitted to the Royal Children's Hospital during the study period, 58 admissions (3.4%) were associated with DRPs. Non-compliance was implicated in 50%. Causality was ranked as "definite" (34.5%), "possible" (56.9%) and "doubtful" (8.6). Two-thirds of admissions associated with DRPs were deemed preventable. Although no patients died from DRPs, four were admitted to the intensive care unit. CONCLUSIONS: The incidence of DRPs as a cause of hospital admission in this study falls within the range of incidences published for the Australian adult population (range, 2.4%-22%). In contrast to findings among Australian adults, a high proportion of admissions for DRPs in this study were associated with non-compliance. The high percentage of preventable admissions indicates that further study is necessary to characterise risk factors within this population and to test prevention strategies.     

Longitudinal assessment of inpatient use and functioning of seriously mentally ill veterans with and without co-occurring substance use disorders

Within a fungal species, a subset of individuals may have more than the minimal complement of chromosomes. If the extra chromosomes are composed primarily of DNA not found in all representatives of the species, they are most appropriately referred to as supernumerary chromosomes. The patterns of repeated DNA sequences on certain supernumerary chromosomes suggest that they have a different evolutionary history from the essential chromosomes in the same genome. Supernumerary chromosomes can carry functional genes and, in at least two fungal species, genes on such chromosomes play important roles in host-pathogen interactions. Supernumerary chromosomes that confer an adaptive advantage in certain habitats, such as the ability to cause disease on a specific host, may be referred to as "conditionally dispensable" chromosomes in order to reflect their importance in some, but not all, growth conditions. In addition to describing the structural and functional characteristics of known supernumerary chromosomes in fungi, this review discusses the relative merits of the terms that have been used to describe them, and establishes experimental criteria for their identification.     

Assessment of the nutritional state of dialysis patients

Obstructive sleep apnea syndrome (OSAS) has been associated with a higher than normal cardiovascular morbidity and mortality. Some OSAS patients lack the sleep-related, nocturnal decrease, or "dip," in blood pressure which is seen in normal individuals. These subjects, called "non-dippers," may be at greater risk for cardiovascular problems. We studied 40 OSAS patients (including 3 women) and 6 control subjects, all identified by polysomnography, for nocturnal blood pressure "dipping." We performed a second nocturnal polysomnogram to determine their apnea and hypopnea indices, (A + H)I, and oxygen saturation levels at the beginning of the study and then initiated 48 hours of ambulatory blood pressure monitoring, with data points collected every 30 minutes. Controls, which included one hypertensive subject, were all dippers. Nineteen OSAS subjects (48% of OSAS individuals) were systolic non-dippers and only 9 of them (22.5%) were diastolic non-dippers. We considered the following clinical variables as potential predictors of non-dipping: age, body mass index, respiratory disturbance index, years of reported loud snoring by bed partners, lowest oxygen saturation during nocturnal sleep, and percentage of sleep time spent with oxygen saturation below 90%. Multiple regression analyses indicated respiratory disturbance index as the only significant variable for systolic (p = 0.04) and diastolic (p = 0.03) blood pressure non-dipping. When we forced the following two nonsignificant variables into the model, they showed a very meager impact: number of years with reported loud snoring (p = 0.4 and p = 0.5, respectively for systolic and diastolic blood pressure non-dipping) and age (p = 0.5 and p = 0.6). The calculated model explained only a low percentage of the variance with an r2 of 0.25 and 0.26 for systolic and diastolic blood pressure non-dipping, respectively. Analysis of hypertension/normotension and dipping/non-dipping failed to show a significant relationship in the studied population. Fifty percent of the normotensive OSAS subjects were non-dippers and 43% of the hypertensive OSAS subjects were also non-dippers. We found a relationship between increasing respiratory disturbance index and increasing average 24-hour systolic blood pressure only when OSAS subjects were non-dippers and hypertensive.     

Transmembrane passage of cytokine-inducing bacterial products across new and reprocessed polysulfone dialyzers

The widespread use of bicarbonate dialysate and reprocessed high-efficiency and "high-flux" dialyzers has raised concerns about the increased risk of reverse-transfer of dialysate contaminants into the blood compartment. To evaluate this concern, the reverse-transfer of bacterial products from contaminated bicarbonate dialysate into the blood compartment was compared during in vitro dialysis with new or reprocessed high-flux polysulfone dialyzers. In vitro dialysis was carried out at 37 degrees C by use of a counter-current recirculating loop dialysis circuit with either new high-flux polysulfone dialyzers or dialyzers reprocessed once or 20 times with formaldehyde (0.75%) and bleach (< 1%) with an automated system. Heparinized whole blood from healthy volunteers was circulated through the blood compartment, and bicarbonate dialysate was circulated in the dialysate compartment. The dialysate was challenged sequentially by 1:1000 and 1:100 dilutions of a sterile Pseudomonas aeruginosa culture supernatant (bacterial challenge). Samples were drawn from the blood and dialysate compartments 1 h after each challenge. Peripheral blood mononuclear cells (PBMC) were harvested by Ficoll-Hypaque separation from whole blood in the blood compartment and a 5 x 10(6) PBMC/mL cell suspension was prepared. Likewise, dialysate samples (0.5 mL) were added to 0.5 mL suspension of 5 x 10(6) PBMC/mL drawn at baseline. All PBMC suspensions were incubated upright in a humidified atmosphere at 37 degrees C with 5% CO2 for 24 h, and total interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor-alpha (TNF alpha) cytokine production (cell-associated and secreted) was measured by radioimmunoassay. Eight experiments were performed for each arm of the study with the same donor for each arm. One hour after contaminating the dialysate with a 1:1000 dilution of the bacterial challenge, IL-1 alpha production by PBMC harvested from the blood compartment was 160 +/- 0, 171 +/- 11, and 270 +/- 35 pg, respectively, for new dialyzers, dialyzers reprocessed once, and dialyzers reprocessed 20 times (P = 0.004). One hour after challenging the dialysate with 1:100 dilution, IL-1 alpha production by PBMC harvested from the blood compartment was 188 +/- 20, 228 +/- 35, and 427 +/- 67 pg, respectively, for new dialyzers, dialyzers reprocessed once, and dialyzers reprocessed 20 times (P = 0.006). IL-1 alpha production by PBMC from dialyzers reprocessed 20 times was significantly greater than both new and dialyzers reprocessed once. However, there were no significant differences between new dialyzers and dialyzers reprocessed once. Similarly, after the 1:1000 challenge, TNF alpha production by PBMC harvested from the blood compartment was 160 +/- 0, 160 +/- 0, and 213 +/- 22 pg, respectively, for new dialyzers, dialyzers reprocessed once, and dialyzers reprocessed 20 times (P = 0.008). After the 1:100 challenge, TNF alpha production was 168 +/- 8, 188 +/- 20, and 225 +/- 32 pg, respectively, for new dialyzers, dialyzers reprocessed once, and dialyzers reprocessed 20 times (P = 0.20). These results demonstrate that reprocessing of high-flux polysulfone dialyzers with bleach increases the risk of reverse-transfer of bacterial products from contaminated dialysate, and this risk appears to increase with the number of reuses. Consequently, units that reprocess membranes with bleach and have suboptimal water quality might subject their patients to a higher risk of cytokine-related morbidity.     

Yearly stepwise increments of the growth hormone dose results in a better growth response after four years in girls with Turner syndrome. Dutch Working Group on Growth Hormone

To optimize the growth promoting effect of growth hormone (GH), 65 previously untreated girls with Turner syndrome (TS), chronological age (CA) 2-11 yr, were randomized into 3 dosage regimen groups: A, B, and C, with a daily recombinant-human GH dose during 4 study years of 4-4-4-4, 4-6-6-6, and 4-6-8-8 IU/m2 b.s. The first GH dosage increase in groups B and C resulted in a significantly higher mean height velocity (HV) compared with constant dose group A. During the third year, when the dose was raised again only in group C, mean HV was significantly higher in groups B and C than in group A, and in group C compared with group B. In year 4 only group C mean HV remained significantly higher than group A. The pattern of change in HSDSCA (Dutch-Swedish-Danish Turner references) was identical; however, in year 4 mean delta HSDSCA in group B also remained significantly higher than group A. After 4 yr GH treatment, the following was determined. 1) The mean delta HSDSCA was significantly higher for groups B and C compared with group A, but not significantly different between groups B and C. 2) Although significantly higher compared with estimated values for untreated Dutch girls with TS, bone maturation of the GH treated girls was not significantly different between groups. 3) It was positively related with the degree of bone age (BA) retardation at start of study and negatively with baseline CA. 4) Both the modified Index of Potential Height (mIPHRUS) and a recently developed Turner-specific final height (FH) prediction method (PTSRUS), based on regression coefficients for H, CA, and bone age, showed significant increases in mean FH prediction, without significant differences between groups. PTSRUS values were markedly higher than the mIPHRUS values. Dose dependency could be shown for the area under the curve (AUC) for GH, but delta HSDSCA was not linearly related with AUC. Baseline GH binding protein (BP) levels were in 84% of the cases within the normal age range; the decrease in mean levels after 6 months GH was not significant. Mean insulin-like growth factor I (IGF-I) and IGFBP-3 plasma levels increased significantly, without significant differences between groups. delta HSDSCA during GH was dependent on IGF-I plasma levels at baseline and during the study period, beta-0.002 and beta-0.0004. Thus, a stepwise GH-dosing approach reduced the "waning" effect of the growth response after 4 yr treatment without undue bone maturation. FH prediction was not significantly different between treatment groups. Irrespective of the GH dose used, initiation of GH treatment at a younger age was beneficial after 4 yr GH when expressed as actual cm gained or as gain in FH prediction, but was not statistically significant when expressed as delta HSDSCA over the study period.     

Redundant multicast routing in multilayer networks with shared risk resource groups: Complexity,models and algorithms

This paper presents a redundant multicast routing problem in multilayer networks that arises from large-scale distribution of realtime multicast data (e.g., Internet TV, videocasting, online games, stock quotes). Since these multicast services commonly operate in multilayer networks, the communications paths need to be robust against a single router or link failure as well as multiple such failures due to shared risk link groups (SRLGs). The main challenge of this multicast is to ensure the service availability and reliability using a path protection scheme, which is to find a redundant path that is SRLG-disjoint (diverse) from each working path. The objective of this problem is, therefore, to find two redundant multicast trees, each from one of the two redundant sources to every destination, at a minimum total communication cost whereas two paths from the two sources to every destination are guaranteed to be SRLG-diverse (i.e., links in the same risk group are disjoint). In this paper, we present two new mathematical programming models, edge-based and path-based, for the redundant multicast routing problem with SRLG-diverse constraints. Because the number of paths in path-based model grows exponentially with the network size, it is impossible to enumerate all possible paths in real life networks. We develop three approaches (probabilistic, non-dominated and nearly non-dominated) to generate potentially good paths that may be included in the path-based model. This study is motivated by emerging applications of internet-protocol TV service, and we evaluate the proposed approaches using real life network topologies. Our empirical results suggest that both models perform very well, and the nearly non-dominated path approach outperforms all other path generation approaches.     

Integrated simulation framework for the process planning of ships and offshore structures

Recently, requests for accurate process planning using simulation have been increasing in many engineering fields, including the shipbuilding industry. To date, designers of shipyards have developed in-house simulation systems or used commercial systems such as the QUEST by Dassault system when requests for the simulation of process planning have occurred. However, these methods have some limitations. First, it requires a lot of time to develop a new in-house simulation system. In addition, it is hard to reuse previously developed systems when developing a new one and it is also hard for these to satisfy the various needs of shipyards effectively.     

Frictional properties of VA‐mode alignment‐film surfaces studied by frictional force microscopy

Abstract— The surface‐friction characteristics of the post‐bake temperature were compared to that of the rubbing condition on VA‐mode alignment films (AFs) using frictional force microscopy (FFM). The surface roughness and the surface frictional force increased when the temperature was elevated. However, the frictional asymmetry could not be detected by the frictional loop due to the instability of the side‐chain molecular arrangement. For the inter‐influences of the total friction and surface roughness, the density of the side chain was changed and it was intentionally rubbed for evaluation. The results showed that the total friction was higher when the rubbing was stronger and side‐chain density lower, and the surface roughness also increased in the same manner. This can be explained by the potential interaction due to the curved structure of the side‐chain surface that establishes the probe that is scanned and the top surface layer. In order to confirm the influence of the pre‐tilt angle on the tilt of the side chain, a test cell was produced under the same conditions and evaluated. The results showed that the pre‐tilt‐angle decreased according to the difference in density of the side chain and strength of rubbing after injecting liquid‐crystal (LC).     

一种新颖的强度调制型绞合式光纤应变传感器

介绍一种本征型强度调制绞合式光纤应变传感器,分析了该传感器的应变传感原理。理论与实验均表明,该传感器既能测量拉应变,又能测量压应变,对应变的响应具有良好的线性和重复性、灵敏度高、无迟滞现象。