bluuebunny/crossref_metadata_2025 huggingface dataset:
Speed Constancy and the Perception of Distance
Authors: Tozawa Junko
Published: December 2007

The distance-calibration hypothesis states that retinal velocity is scaled by using distance cues, and judged velocity remains unchanged when distance is changed. The relational hypothesis states that judged velocity depends on retinal velocities, and is proportional to judged distance. These hypotheses were compared in three experiments where the movements of the standard stimulus and the comparison stimulus were manipulated by the ratio of the angular velocity of the comparison stimulus to the angular velocity of the standard stimulus. The presentation conditions of the standard stimulus and the comparison stimulus, and the colour cues of the two stimuli were also manipulated in order to change the strength of the cues available to the observers. The results indicate that judged velocities and the relationship of judged distance and velocity depend on the strength of the cues. When cues are strong, the distance-calibration hypothesis adequately explains speed constancy. When cues are weak, judged velocity and the relationship between judged distance and velocity are consistent with the prediction of the relational hypothesis. The perceived speed of a stimulus depends not only on the physical speed of the stimulus but also on non-motion cues, some of which are distance cues involved in depth perception.
Changes in severe thunderstorm environment frequency during the 21st century caused by anthropogenically enhanced global radiative forcing
Authors: Trapp Robert J. , Diffenbaugh Noah S. , Brooks Harold E. , Baldwin Michael E. , Robinson Eric D. , Pal Jeremy S.
Published: December 2007

Severe thunderstorms comprise an extreme class of deep convective clouds and produce high-impact weather such as destructive surface winds, hail, and tornadoes. This study addresses the question of how severe thunderstorm frequency in the United States might change because of enhanced global radiative forcing associated with elevated greenhouse gas concentrations. We use global climate models and a high-resolution regional climate model to examine the larger-scale (or “environmental”) meteorological conditions that foster severe thunderstorm formation. Across this model suite, we find a net increase during the late 21st century in the number of days in which these severe thunderstorm environmental conditions (NDSEV) occur. Attributed primarily to increases in atmospheric water vapor within the planetary boundary layer, the largest increases in NDSEV are shown during the summer season, in proximity to the Gulf of Mexico and Atlantic coastal regions. For example, this analysis suggests a future increase in NDSEV of 100% or more in locations such as Atlanta, GA, and New York, NY. Any direct application of these results to the frequency of actual storms also must consider the storm initiation.
Genetic drift at expanding frontiers promotes gene segregation
Authors: Hallatschek Oskar , Hersen Pascal , Ramanathan Sharad , Nelson David R.
Published: December 2007

Competition between random genetic drift and natural selection play a central role in evolution: Whereas nonbeneficial mutations often prevail in small populations by chance, mutations that sweep through large populations typically confer a selective advantage. Here, however, we observe chance effects during range expansions that dramatically alter the gene pool even in large microbial populations. Initially well mixed populations of two fluorescently labeled strains of
Escherichia coli
develop well defined, sector-like regions with fractal boundaries in expanding colonies. The formation of these regions is driven by random fluctuations that originate in a thin band of pioneers at the expanding frontier. A comparison of bacterial and yeast colonies (
Saccharomyces cerevisiae
) suggests that this large-scale genetic sectoring is a generic phenomenon that may provide a detectable footprint of past range expansions.
Use of Ivermectin to Treat an Institutional Outbreak of Scabies in a Low-Resource Setting
Authors: Garcia Coralith , Iglesias David , Terashima Angélica , Canales Marco , Gotuzzo Eduardo
Published: December 2007

In a limited-resource hospital in Lima, Peru, 23 (63.9%) of 36 healthcare workers developed pruritus and/or skin lesions after contact with a patient with classic scabies. Of these 23, a total of 5 healthcare workers had scabies confirmed by microscopy. Oral ivermectin was used to control the outbreak effectively.
Use of Safety Devices and the Prevention of Percutaneous Injuries Among Healthcare Workers
Authors: Valls Victoria , Lozano M. Salud , Yánez Remedios , Martínez María José , Pascual Francisco , Lloret Joan , Ruiz Juan Antonio
Published: December 2007

Objective.

To study the effectiveness of safety devices intended to prevent percutaneous injuries.

Design.

Quasi-experimental trial with before-and-after intervention evaluation.

Setting.

A 350-bed general hospital that has had an ongoing educational program for the prevention of percutaneous injuries since January 2002.

Methods.

In October 2005, we implemented a program for the use of engineered devices to prevent percutaneous injury in the emergency department and half of the hospital wards during the following procedures: intravascular catheterization, vacuum phlebotomy, blood-gas sampling, finger-stick blood sampling, and intramuscular and subcutaneous injections. The nurses in the wards that participated in the intervention received a 3-hour course on occupationally acquired bloodborne infections, and they had a 2-hour “hands-on” training session with the devices. We studied the percutaneous injury rate and the direct cost during the preintervention period (October 2004 through March 2005) and the intervention period (October 2005 through March 2006).

Results.

We observed a 93% reduction in the relative risk of percutaneous injuries in areas where safety devices were used (14 vs 1 percutaneous injury). Specifically, rates decreased from 18.3 injuries (95% confidence interval [CI], 5.9-43.2 injuries) to 0 injuries per 100,000 patients in the emergency department (P = .002) and from 44.0 injuries (95% CI, 20.1-83.6 injuries) to 5.2 injuries (95% CI, 0.1-28.8 injuries) per 100,000 patient-days in hospital wards (P = .007). In the control wards of the hospital (ie, those where the intervention was not implemented), rates remained stable. The direct cost increase was €0.558 (US$0,753) per patient in the emergency department and €0.636 (US$0,858) per patient-day in the hospital wards.

Conclusion.

Proper use of engineered devices to prevent percutaneous injury is a highly effective measure to prevent these injuries among healthcare workers. However, education and training are the keys to achieving the greatest preventative effect.
Determination of Risk Factors Associated With Isolation of Linezolid-Resistant Strains of Vancomycin-Resistant Enterococcus
Authors: Pogue Jason M. , Paterson David L. , Pasculle A. William , Potoski Brian A.
Published: December 2007

Objective.

To identify independent risk factors associated with isolation of linezolid-resistant, vancomycin-resistant Enterococcus (VRE).

Design.

A retrospective, case-case-control study.

Setting.

A tertiary care, academic medical center.

Methods.

VRE isolates from clinical cultures were retrospectively analyzed for linezolid resistance during our 18-month study period. Clinical data were obtained from electronic patient records, and the risk factors associated with isolation of linezolid-resistant VRE were determined by comparison of 2 case groups with a control group.

Results.

A total of 20% of the VRE isolates analyzed during the study period were linezolid resistant, and resistant isolates were most commonly recovered from the urine (40% of resistant isolates). Risk factors found to be associated with isolation of linezolid-resistant VRE were peripheral vascular disease and/or the receipt of a solid organ transplant, total parenteral nutrition, piperacillin-tazobactam, and/or cefepime. Only 25% of patients from whom linezolid-resistant VRE was isolated had previous linezolid exposure, and in the multivariate model this was not found to be a risk factor associated with the isolation of linezolid-resistant VRE.

Conclusions.

The results of this analysis suggest that there is horizontal transmission of linezolid-resistant VRE in our institution and highlight the need for improved infection control measures. Furthermore, the high incidence of linezolid-resistant VRE demands a reassessment of our empirical antibiotic selection for patients infected with VRE.
Factors That Influenced Rates of Influenza Vaccination Among Employees of Wisconsin Acute Care Hospitals and Nursing Homes During the 2005-2006 Influenza Season
Authors: Borlaug Gwen , Newman Alexandra , Pfister John , Davis Jeffrey P.
Published: December 2007

Hospitals and nursing homes were surveyed in 2006 to obtain information on employee influenza vaccination programs and baseline rates of influenza vaccination among employees. Results were used to make recommendations for improving employees' 2007 influenza vaccination rates. Facilities should continue to provide convenient and free vaccination programs, offer education to promote vaccination, and use signed declination forms.
Comparison of Hospitalwide Surveillance and Targeted Intensive Care Unit Surveillance of Healthcare-Associated Infections
Authors: Weber David J. , Sickbert-Bennett Emily E. , Brown Vickie , Rutala William A.
Published: December 2007

Objectives.

To assess the surveillance coverage obtained with Centers for Disease Control and Prevention (CDC)-recommended surveillance of healthcare-associated infections (HAIs), which is focused on intensive care units (ICUs) and emphasizes device-related infections (ie, those associated with central venous catheters, ventilators, and/or urinary catheters), compared with the surveillance coverage achieved by comprehensive hospitalwide surveillance. In addition, we assessed whether the infection rates in step-down units more resemble those in wards or ICUs.

Methods.

Review of prospectively obtained, comprehensive hospitalwide surveillance data from 2004 through 2005 for an acute care tertiary care hospital with approximately 700 beds. Surveillance data was obtained by trained infection control professionals using standard CDC criteria for HAIs.

Results.

CDC-recommended ICU surveillance for catheter-related bloodstream infection (BSI) and ventilator-associated pneumonia would have detected only 87 (21.4%) of 407 catheter-related BSIs and only 66 (37.9%) of 174 respiratory tract infections that occurred in the medical and surgical services. Only 31 (34.8%) of 89 infections caused by methicillin-resistant Staphylococcus aureus and 7 (31.8%) of 22 infections caused by vancomycin-resistant Enterococcus occurred in our adult ICUs.

Conclusions.

Rates of HAIs were highest in the ICUs, intermediate in step-down units, and lowest in the wards. The rates of infections in the step-down units were more similar to those in the wards than to those in the ICUs. To prevent HAIs, more comprehensive surveillance may be indicated.
Identifying Opportunities to Enhance Environmental Cleaning in 23 Acute Care Hospitals
Authors: Carling P. C. , Parry M. F. , Von Beheren S. M. ,   Healthcare Environmental Hygiene Study Group
Published: December 2007

Objective.

The quality of environmental hygiene in hospitals is under increasing scrutiny from both healthcare providers and consumers because the prevalence of serious infections due to multidrug-resistant pathogens has reached alarming levels. On the basis of the results from a small number of hospitals, we undertook a study to evaluate the thoroughness of disinfection and cleaning in the patient's immediate environment and to identify opportunities for improvement in a diverse group of acute care hospitals.

Methods.

Prospective multicenter study to evaluate the thoroughness of terminal room cleaning in hospitals using a novel targeting method to mimic the surface contamination of objects in the patient's immediate environment.

Setting.

Twenty-three acute care hospitals.

Results.

The overall thoroughness of terminal cleaning, expressed as a percentage of surfaces evaluated, was 49% (range for all 23 hospitals, 35%-81%). Despite the tight clustering of overall cleaning rates in 21 of the hospitals, there was marked variation within object categories, which was particularly notable with respect to the cleaning of toilet handholds, bedpan cleaners, light switches, and door knobs (mean cleaning rates, less than 30%; institutional ranges, 0%-90%). Sinks, toilet seats, and tray tables, in contrast, were consistently relatively well cleaned (mean cleaning rates, over 75%). Patient telephones, nurse call devices, and bedside rails were inconsistently cleaned.

Conclusion.

We identified significant opportunities in all participating hospitals to improve the cleaning of frequently touched objects in the patient's immediate environment. The information obtained from such assessments can be used to develop focused administrative and educational interventions that incorporate ongoing feedback to the environmental services staff, to improve cleaning and disinfection practices in healthcare institutions.
Impact of an Infection Control Program on the Prevalence of Nosocomial Infections at a Tertiary Care Center in Switzerland
Authors: Ebnöther Corina , Tanner Beate , Schmid Flavia , Rocca Vittoria La , Heinzer Ivo , Bregenzer Thomas
Published: December 2007

Objective.

To study the impact of a multimodal infection control program on the rate of nosocomial infections at a 550-bed tertiary care center.

Methods.

Before and after the implementation of an infection control program, the rate of nosocomial infection was recorded in time-interval prevalence studies. Hand hygiene compliance was studied before and after the intervention. As a surrogate marker of compliance, the amount of alcohol-based hand rub consumed before the intervention was compared with the amount consumed after the intervention. The intervention included additional staff for infection control, repeated instructions for hand hygiene, new guidelines for preoperative antibiotic prophylaxis, and isolation of patients infected or colonized with multidrug-resistant bacteria.

Results.

The rate of nosocomial infection decreased from approximately 11.7% to 6.8% in 2 years. The rate of hand hygiene compliance increased by 20.0%; it was 59.0% before the intervention and increased to 79.0% afterward. These results correlate with data on the consumption of alcohol-based hand rub, but not with data on the use of antibiotics.

Conclusion.

Within 2 years, a multimodal infection control program intervention such as this one may reduce the rate of nosocomial infection at a tertiary care center by more than one-third and improve both the quality of care and patient outcomes. It may also generate considerable savings. Therefore, such programs should be promoted not only by hospital epidemiologists but also by hospital administrators.
Comparative Analysis of 75th Percentile Durations for Neurosurgical Procedures in France and in US National Noscomial Infection Surveillance System Data
Authors: Lietard Claire , Thébaud Véronique , Burnichon Géraldine , Besson Gérard , Lejeune Benoist
Published: December 2007

The duration of surgical procedures and the 75th percentiles of those durations are considered in calculation of the US National Nosocomial Infection Surveillance (NNIS) system risk index score. To compare the durations of neurosurgical procedures in a hospital in western France with the durations in the NNIS data, 6,136 neurosurgical patients were followed up to determine surgical site infection rates. The surgical site infection rate was 1.9%, and the 75th percentile durations were lower than those in the NNIS data. The values from the NNIS data are thus inadequate for this neurosurgical center.
Transitioning toward Evidence‐Based Research in the Health Sciences for the XXI Century
Authors: Chiappelli Francesco , Cajulis Olivia S.
Published: December 2007

This article discusses some of the misconceptions of evidence‐based research in the health sciences. It proposes that since not all treatments in medicine and dentistry can be evidence‐based, clinical applications of the evidence‐based process should become a specialty. The case is particularly evident in dentistry. Therefore dentistry is taken in this article as a model for discussion. We propose that to approach dentistry from the viewpoint of the patient‐oriented evidence that matters (POEM) is perfectly acceptable so far as we also engage in the process of research evaluation and appraisal in dentistry (READ). We distinguish between dentistry based on the evidence, and evidence‐based dentistry. We argue that when invoking an evidence‐based approach to dentistry or medicine, it is not sufficient to establish the ‘levels of evidence’, but rather that all evidence‐based clinical intervention must undergo the stringent process of evidence‐based research so that clinical practice guidelines be revised based on the best available evidence.
Identification of Plum pox virus Pathogenicity Determinants in Herbaceous and Woody Hosts
Authors: Salvador B. , Delgadillo M. O. , Sáenz P. , García J. A. , Simón-Mateo C.
Published: December 2007

Plum pox virus (PPV) is a member of the genus Potyvirus that is able to infect a large variety of plant species, including trees of the genus Prunus, its natural host. When some PPV isolates are propagated for an extended time in herbaceous plants, their ability to infect trees is reduced. The molecular basis of this change in host infectivity is poorly understood. We report the construction of hybrid viruses from cDNA clones of two D-strain isolates of PPV, PPV-D and PPV-R, which differ in their host range. PPV-D can infect GF305 peach seedlings efficiently, however, it is unable to infect Nicotiana clevelandii plants. Conversely, PPV-R infects N. clevelandii, but not GF305 peach seedlings. The analyses of the hybrid viruses showed that, although determinants of PPV pathogenicity are extensively spread throughout the PPV genome, the 3′ terminal region of the PPV-R genome, including the 3′ noncoding region and the coding regions for the coat protein (CP), NIb, and part of NIa protein, is sufficient to confer infectivity of N. clevelandii in a PPV-D background. Our data demonstrate a high concentration of amino acid substitutions in the CP and a host-specific effect of a deletion at the N terminus of this protein in PPV pathogenicity in peach and N. clevelandii infectivity experiments. These results suggest that relevant host specificity determinants are located in the N-terminal region of the CP. The analyses of the PPV-R and PPV-D chimeras also showed that key host-specific pathogenicity determinants lie in the 5′ terminal third of the PPV genome, a region that spans proteins P1, HCPro, and P3. The selection of mutations in only a few specific residues in proteins P1, P3, and 6K1 after partial adaptation of a chimeric virus (BD-GFP) to N. clevelandii further suggests a relevant role for these proteins in host adaptation.
Bond tilting and sliding friction in a model of cell adhesion
Authors: Reboux S , Richardson G , Jensen O.E
Published: December 2007

As a simple theoretical model of a cell adhering to a biological interface, we consider a rigid cylinder moving in a viscous shear flow near a wall. Adhesion forces arise through intermolecular bonds between receptors on the cell and their ligands on the wall, which form flexible tethers that can stretch and tilt as the base of the cell moves past the wall; binding kinetics is assumed to follow a standard model for slip bonds. By introducing a finite resistance to bond tilting, we use our model to explore the territory between previous theoretical models that allow for either zero or infinite resistance to bond rotation. A microscale calculation (for two parallel sliding plates) reveals a nonlinear force–speed relation arising from bond formation, tilting and breakage. Two distinct types of macroscale cell motion are then predicted: either bonds adhere strongly and the cell rolls (or tank treads) over the wall without slipping, or the cell moves near its free-stream speed with bonds providing weak frictional resistance to sliding. The model predicts bistability between these two states, implying that at critical shear rates the system can switch abruptly between rolling and free sliding, and suggesting that sliding friction arising through bond tilting may play a significant dynamical role in some cell-adhesion applications.
Intraspecific variation in a generalist herbivore accounts for differential induction and impact of host plant defences
Authors: Kant Merijn R , Sabelis Maurice W , Haring Michel A , Schuurink Robert C
Published: December 2007

Plants and herbivores are thought to be engaged in a coevolutionary arms race: rising frequencies of plants with anti-herbivore defences exert pressure on herbivores to resist or circumvent these defences and vice versa. Owing to its frequency-dependent character, the arms race hypothesis predicts that herbivores exhibit genetic variation for traits that determine how they deal with the defences of a given host plant phenotype. Here, we show the existence of distinct variation within a single herbivore species, the spider mite
Tetranychus urticae
, in traits that lead to resistance or susceptibility to jasmonate (JA)-dependent defences of a host plant but also in traits responsible for induction or repression of JA defences. We characterized three distinct lines of
T. urticae
that differentially induced JA-related defence genes and metabolites while feeding on tomato plants (
Solanum lycopersicum
). These lines were also differently affected by induced JA defences. The first line, which induced JA-dependent tomato defences, was susceptible to those defences; the second line also induced JA defences but was resistant to them; and the third, although susceptible to JA defences, repressed induction. We hypothesize that such intraspecific variation is common among herbivores living in environments with a diversity of plants that impose diverse selection pressure.
Analytical and Experimental Characterization of Bonding Over Active Circuitry
Authors: Zhang Li , Gumaste Vijaylaxmi , Poddar Anindya , Nguyen Luu , Schulze Gary
Published: December 2007

Placing active circuitry directly underneath the bond pads is an effective way to reduce the die size, and hence to achieve lower cost per chip. The main concern with such design is the possible mechanical damage to the underlying circuitry during the wire bonding process. For example, the initial bond force and subsequent ultrasonic vibration may cause cracks within the dielectric layer. The cracks can penetrate through the active circuitry underneath, resulting in electrical failures to the silicon device. In this paper, a finite element based methodology was developed to study the stress behavior of bond pad structures during thermosonic wire bonding. The focus of our analysis is on dielectric layer crack, which was the dominant failure mode observed. The finite element (FE) model is 3-D based and contains the wire ball, the bond pad, and the underpad structure. The model was subjected to various bond force/ultrasound conditions, and the stresses were compared with the percentage of cracked pads in the real life bonding experiments. By using the volume-averaged, incremental first principal stress at the dielectric layer as the stress criterion, we achieved a reasonably good correlation with the experiments. In addition, we found that the dynamic friction at the bond interface is critical in stress distributions at the bond pad. Based on this, we have provided an explanation on how stresses progress during a typical bond force. Furthermore, the stress progression pattern was shown to correlate well with the different crack patterns. The FE model established a baseline upon which more designs with bonding over active circuitry can be analyzed and evaluated for crack resistance to thermosonic wire bonding.
On Moisture Diffusion Modeling Using Thermal-Moisture Analogy
Authors: Yoon Samson , Han Bongtae , Wang Zhaoyang
Published: December 2007

Thermal-moisture analogy schemes for a moisture diffusion analysis are reviewed. Two schemes for practical applications are described using the governing equations of heat and mass diffusions: (1) direct analogy and (2) normalized analogy. The schemes are implemented to define valid domains of application. The results corroborate that the direct analogy is valid only for single-material systems, but the normalized analogy can be extended to multimaterial systems if thermal loading conditions are isothermal, spatially as well as temporally.
An Expedient Experimental Technique for the Determination of Thermal Cycling Fatigue Life for BGA Package Solder Balls
Authors: Tunga Krishna , Sitaraman Suresh K.
Published: December 2007

Although accelerated thermal cycling has been widely used in electronics industry to qualify electronic packages, efforts to reduce the time and cost associated with such qualification techniques are continuously being sought. This paper outlines a laser-moiré based experimental technique to quickly assess the thermal cycling reliability of microelectronic packages. Unlike accelerated thermal cycling that takes several months to complete, the proposed technique takes one to two weeks to complete and does not suffer from various modeling assumptions used in finite-element simulations. The developed technique has been used to determine the thermomechanical reliability of organic and ceramic ball grid array packages, and it is shown that the number of cycles determined by the proposed technique is comparable to the number of cycles determined through accelerated thermal cycling.
Nondestructive Evaluation of Thermal Phase Growth in Solder Ball Microjoints by Synchrotron Radiation X-Ray Microtomography
Authors: Tsuritani Hiroyuki , Sayama Toshihiko , Uesugi Kentaro , Takayanagi Takeshi , Mori Takao
Published: December 2007

In high-density packaging technology, one of the most important issues is the reliability of the microjoints connecting large scale integrated circuit chips to printed circuit boards electrically and mechanically. The development of nondestructive testing methods with high spatial resolution is expected to enhance reliability. An X-ray microtomography system called SP-μCT has been developed in Super Photon ring-8 GeV (SPring-8), the largest synchrotron radiation facility in Japan. In this work, SP-μCT was applied in the nondestructive evaluation of microstructure evolution, that is, the phase growth due to thermal cyclic loading in solder ball microjoints. Simulating solder microjoints used in a flip chip, specimens were fabricated by joining a Sn–Pb eutectic solder ball 100 μm in diameter to a steel pin in the usual reflow soldering process. The phase growth process was determined by observing the computed tomography (CT) images obtained consecutively at the fixed point of the target joining. In the reconstructed CT images, the distribution of the constituent phases in the Sn–Pb eutectic solder was identified based on the estimation value of the X-ray linear attenuation coefficient. Consequently, the microstructure images obtained nondestructively by SP-μCT provided us with the following useful information for evaluating the reliability of the solder microjoints. First, each phase involves not dispersing particles but a three-dimensional monolithic structure like a sponge. Second, the phase growth proceeds in such a way that the average phase size to the fourth power increases proportionally to the number of cycles. Finally, in the vicinity of the joining interface, more rapid phase growth occurs compared to the other regions because local thermal strain due to the mismatch of thermal expansion leads to a remarkable phase growth.
A Theoretical Analysis of the Concept of Critical Clearance Toward a Design Methodology for the Flip-Chip Package
Authors: Wan J. W. , Zhang W. J. , Bergstrom D. J.
Published: December 2007

In this article, we present a theoretical study on the concept known as critical clearance for flip-chip packages. The critical clearance phenomenon was first observed in an experiment reported by Gordon et al. (1999, “A Capillary-Driven Underfill Encapsulation Process,” Advanced Packaging, 8(4), pp. 34–37). When the clearance is below a critical value, filling time begins to increase dramatically, and when the clearance is above this value, the influence of clearance on filling time is insignificant. Therefore, the optimal solder bump density in a flip-chip package should be one with a clearance larger than the critical clearance. The contribution of our study is the development of a quantitative relation among package design features, flow characteristics, and critical clearance based on an analytical model we developed and reported elsewhere. This relation is further used to determine critical clearance given a type of underfill material (specifically the index n of the power-law constitutive equation), the solder bump pitch, and the gap height; further the flip-chip package design can be optimized to make the actual clearance between solder bumps greater than its corresponding critical clearance.
What's being used to spike your drink? Alleged spiked drink cases in inner city London
Authors: Greene S L , Shiew C M , Streete P , Mustchin S J , Hugget D , Earl B , Dargan P I
Published: December 2007

Objectives

To determine the incidence and character of drink spiking in an urban population of patients within the UK presenting to an emergency department concerned they had consumed a deliberately contaminated drink.

Study design

Prospective case series determining the presence and quantity of sedative and illicit drugs, and ethanol in biological samples (blood and urine) obtained from consenting patients >18 years of age presenting to a large inner city London emergency department alleging they had consumed a spiked drink within the previous 12 h.

Results

Biological samples were obtained from 67 (blood) and 75 (urine) of 78 study participants. 82% of participants were female, mean age 24 years. Mean time from alleged exposure to biological sampling was 5.9 h (range 1–12 h). Ethanol was detected in 89.7% of participants. Mean serum ethanol concentration was 1.65 g/l (range 0.04–3.1 g/l); 60% of participants had a serum ethanol concentration associated with significant intoxication (>1.5 g/l). Illicit drugs were detected in 12 (15%) participants; 7 denied intentional exposure (3 methylenedioxymethamphetamine, 3 cannabis, 1 γ-hydroxybutyrate). Medicinal drugs were detected in 13 participants; only 1 exposure was unexplained (benzodiazepine). Overall illicit or medicinal drugs of unexplained origin were detected in 8 (10%) participants. Unexplained sedative drug exposure was detected in only 2 (3%) participants.

Conclusions

Use of sedative drugs to spike drinks may not be as common as reported in the mainstream media. A large number of study participants had serum ethanol concentrations associated with significant intoxication; the source (personal over-consumption or deliberate drink spiking) is unclear.
The Influence of Briefly Presented Randomized Target Motion on the Extraretinal Component of Ocular Pursuit
Authors: Barnes G. R. , Collins C. J. S.
Published: December 2007

We assessed the ability to extract velocity information from brief exposure of a moving target and sought evidence that this information could be used to modulate the extraretinal component of ocular pursuit. A step-ramp target motion was initially visible for a brief randomized period of 50, 100, 150, or 200 ms, but then extinguished for a randomized period of 400 or 600 ms before reappearing and continuing along its trajectory. Target speed (5–20°/s), direction (left/right), and intertrial interval (2.7–3.7 s) were also randomized. Smooth eye movements were initiated after about 130 ms and comprised an initial visually dependent component, which reached a peak velocity that increased with target velocity and initial exposure duration, followed by a sustained secondary component that actually increased throughout extinction for 50- and 100-ms initial exposures. End-extinction eye velocity, reflecting extraretinal drive, increased with initial exposure from 50 to 100 ms but remained similar for longer exposures; it was significantly scaled to target velocity for 150- and 200-ms exposures. The results suggest that extraretinal drive is based on a sample of target velocity, mostly acquired during the first 150 ms, that is stored and forms a goal for generating appropriately scaled eye movements during absence of visual input. End-extinction eye velocity was significantly higher when target reappearance was expected than when it was not, confirming the importance of expectation in generating sustained smooth movement. However, end-extinction eye displacement remained similar irrespective of expectation, suggesting that the ability to use sampled velocity information to predict future target displacement operates independently of the control of smooth eye movement.
Chitosan-TPP Nanoparticle as a Release System of Antisense Oligonucleotide in the Oral Environment
Authors: Dung Tran Huu , Lee Seung-Rok , Han Suhk-Dong , Kim Seon-Jeong , Ju Yeon-Mi , Kim Myong-Soo , Yoo Hoon
Published: December 2007

Antisense oligonucleotide loaded chitosan nanoparticles were prepared and the release of oligonucleotide from chitosan-TPP/oligonucleotide nanoparticles was investigated. Morphological property, zeta potential and particle size of the prepared chitosan/oligonucleotide nanoparticles
were investigated using Field Emission-Scanning Electron Microscope (FE-SEM) and particle size analyzer. The interaction between chitosan and oligonucleotide was confirmed by using capillary zone electrophoresis (CZE), and the released oligonucleotides were determined by spectrophotometric
method. Oligonucleotides formed the complexes with chitosan with a unique morphological property. The release of oligonucleotides from nanoparticles was dependent on loading methods and pH conditions. Chitosan/oligomer-TPP nanoparticles, which was prepared by adding TPP after the formation
of chitosan/oligonucleotide complex, showed the lowest release percent of oligonucleotides with 41.3% at pH 7.0 among the loading methods. The percent release of oligonucleotide from oligonucleotide loaded chitosan nanoparticle at pH 10 was higher than the one in acidic condition (pH 5.0).
The released oligonucleotides from chitosan/oligonucleotide nanoparticles were stable enough for 12 h under the 20% saliva solution. Our results suggest that the sustained release of oligonucleotide from chitosan nanoparticles may be suitable for the local therapeutic application in periodontal
diseases.
Soft-Chemical Synthesis and Electrochemical Characterization of Multicomponent Mn1–x–yCoxNiyO2 Nanostructures
Authors: Kim Tae Woo , Lee Sun Hee , Hwang Seong-Ju , Hyun Sang Hoon , Choy Jin-Ho
Published: December 2007

Nanostructured Mn1–x–y CoxNiyO2 metal oxides are synthesized by one-pot hydrothermal reaction at low temperature. From powder X-ray diffraction and field emission-scanning electron microscopic analyses,
it is found that the crystal structure and crystal morphology of the present materials are tunable by the control of the composition of precursor. 1D nanowires with α-MnO2-type structure are prepared with low substitution rate of Co and Ni, while the increase of substituent
contents leads to the formation of δ-MnO2-structured 3D nanospheres consisting of 2D nanoplates. According to X-ray absorption near edge spectroscopy and chemical analyses, mixed valent CoIII/CoIV and divalent NiII ions are stabilized
in the octahedral Mn sites of α-MnO2- and δ-MnO2-structures. The electrochemical measurements clearly demonstrate that the present nanostructured materials show promising electrode performances for lithium secondary batteries.
Annealing Characteristics of Nanostructured Cu-Fe-P Alloy Processed by Accumulative Roll-Bonding
Authors: Lee Seong-Hee , Lee Chung-Hyo , Yoon Suk-Ja , Han Seung-Zeon , Lim Cha-Yong
Published: December 2007

Annealing characteristics of a nanostructured copper alloy processed by accumulative roll-bonding (ARB) were studied. A nano-grained Cu-Fe-P alloy processed by 8 cycles of the ARB was annealed at various temperatures ranging from 100 to 400 °C for 0.6 ks. The sample still showed
an ultrafine grained (UFG) structure up to 250 °C, however above 300 °C it began to replace by equiaxed and coarse grains due to an occurrence of the conventional static recrystallization. The hardness of the annealed copper decreased largely above 300 °C. These annealing characteristics
of the UFG copper alloy were compared to those of a high purity copper.
Electrospinning of Aligned Biodegradable Polymer Fibers and Composite Fibers for Tissue Engineering Applications
Authors: Tong Ho-Wang , Wang Min
Published: December 2007

Fibrous membranes of aligned poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) fibers have been made through electrospinning. A high-speed rotating drum was used as the fiber collector while the electric field was manipulated by using five knife-edged auxiliary electrodes. It was found
that a high drum rotating speed of 3000 rpm could lead to a nearly perfect alignment of PHBV fibers during electrospinning. Multilayered fibrous structures with each layer having a different direction of fiber alignment could also be constructed through electrospinning. The electrospun PHBV
fibers were further modified by incorporating carbonated hydroxyapatite (HA) nanospheres (up to 20% of HA) in the fibers. The fibrous membranes made of aligned PHBV fibers and made of HA/PHBV composite fibers should be very useful for the tissue engineering of different human body tissues.
Anticancer Drug-Inorganic Nanohybrid and Its Cellular Interaction
Authors: Kim Ju Young , Choi Soo-Jin , Oh Jae-Min , Park Taeun , Choy Jin-Ho
Published: December 2007

An anticancer drug, methotrexate (MTX), has been successfully hybridized with layered double hydroxide (LDH) through co-precipitation route to produce MTX-LDH nanohybrids (MTX-LDH). According to the X-ray diffraction and FT-IR spectroscopy, it was confirmed that MTX molecules are stabilized
in the interlayer space of LDHs by electrostatic interaction, maintaining their functional groups and structural integrity. According to the drug release study, the total amount of released MTX from the LDH lattice was determined to be larger under a simulated intracellular lysosomal condition
(pH = 4.5) than simulated body fluid one (pH = 7.4). It is, therefore, expected that the MTX molecules in MTX-LDH can be effectively released in lysosomes, since the MTX release could be accelerated via ion-exchange reaction and dissolution of LDH in an acidic lysosomal condition. We also
examined the anticancer efficacy of MTX-LDH in human breast adenocarcinoma MCF-7 cells. The cellular uptake of MTX was considerably higher in MTX-LDH-treated cells than in free MTX-treated cells, giving a lower IC50 value for the former than the latter. All the results demonstrated
that the MTX-LDH nanohybrid allows the efficient drug delivery in cells, and thus enhances drug efficacy.
Optical Properties of Eu Doped M-Ga2S4 (M:Zn, Ca, Sr) Phosphors for White Light Emitting Diodes
Authors: Kim Joo Won , Kim Young Jin
Published: December 2007

Eu2+ doped M-thiogallate (MGa2S4, M: Zn, Ca, Sr) phosphors were prepared by solid-state reaction. The dependence of luminescent properties, photoluminescence and cathodoluminescence, on M2+ ions was investigated. ZnGa2S4
: Eu2+, CaGa2S4 : Eu2+, and SrGa2S4 : Eu2+ exhibited a green emission band at 540 nm, 560 nm, and 535 nm, respectively. The red-shift between CaGa2S4 : Eu2+ and SrGa2S4
: Eu2+ was originated from the radius difference of Ca2+ and Sr2+ ions. However, it did not apply to ZnGa2S4 : Eu2+ despite of smaller radius of Zn2+ ion. The particle size of ZnGa2S4 : Eu2+
was much smaller than those of the other thiogallates, leading to extremely low CL emission.
Multi-Wavelength Emitting InGaN/GaN Quantum Well Grown on V-Shaped GaN(1101) Microfacet
Authors: Kang Eun-Sil , Ju Jin-Woo , Kim Jin Soo , Ahn Haeng-Keun , Lee June Key , Kim Jin Hyeok , Shin Dong-Chan , Lee In-Hwan
Published: December 2007

InGaN/GaN multiple quantum wells (MQWs) were successfully grown on the inclined GaN(1101) microfacets. Conventional photolithography and subsequent growth of GaN were employed to generate the V-shaped microfacets along 〈1120〉 direction. The well-developed microfacets observed
by scanning electron microscopy and the clear transmission electron microscope interfacial images indicated that the MQW was successfully grown on the GaN microfacets. Interestingly, cathodoluminescence (CL) spectra measured on the microfacets showed a continuous change in the luminescence
peak positions. The CL peaks were shifted to a longer wavelength from 420 nm to 440 nm as the probing points were changed along upward direction. This could be attributed to the non-uniform distribution of the In composition and/or the wavefunction overlapping between adjacent wells. Present
works thus propose a novel route to fabricate a monolithic white light emitting diode without phosphors by growing the InGaN/GaN MQWs on (1101) facet.
Nanosized LiFePO4 Cathode Materials for Lithium Ion Batteries
Authors: Gu Hal-Bon , Jun Dae-Kyoo , Park Gye-Choon , Jin Bo , Jin En Mei
Published: December 2007

In this study, we prepared nano-particles of LiFePO4 as cathode material for lithium ion batteries by the solid-state reaction. A simple one-step heat treatment has been employed with control of heating temperature and heated LiFePO4 at 650 °C exhibited higher
125 mA h/g of the discharge capacity than 600 °C, 700 °C. To improve conductivity of the inter-particle, carbon coating was carried out by raw carbon or pyrene as carbon sources and their morphological properties of particles on the carbon coating was compared with by FE-SEM, TEM.
From the FE-SEM results, the particles of carbon added LiFePO4 have much smaller size than LiFePO4 as below 300 nm. When adding pyrene (10 wt%), the carbon surrounded non-uniformly with surface of the particles compared with adding raw carbon which wrapped uniformly with
carbon web and it was exhibited 152 mA h/g of the discharge capacity on LiFePO4/C composite cells at 10th cycle.
Catalytic Si–Si/Si–O Dehydrocoupling of 1,1-Dihydrotetraphenylsilole to Optoelectronic Polysiloles with Colloidal Silver Nanoparticles
Authors: Kim Bo-Hye , Cho Myong-Shik , Kim So-Yeun , Kim You-Jeong , Woo Hee-Gweon , Kim Do-Heyoung , Sohn Honglae
Published: December 2007

The combinative Si–Si/Si–O dehydrocoupling at ambient air atmosphere of 1,1-dihydrotetraphenylsilole 1 with 2 mol% of AgNO3 and Ag2 SO4 in toluene at 90 °C produces optoelectronic polysiloles 2 in high yield. The complexes
such as Cp2Co, Cp2Ni, Cp2ZrCl2/Red-Al, and AgCl were found to be ineffective for the dehydrocoupling of 1. The polysiloles mainly have Si—Si bonds along with the small portion of Si—O bonds in the polymer backbone chain. Interestingly,
the Si–O linkage increased with increasing the concentration of catalyst AgNO3, implying that while Ag(0) species catalyze the Si–Si dehydrocoupling, Ag(I) species catalyze the Si–O dehydrocoupling along with the simultaneous oxidation of NO3−
ion to NO2. The silver complexes transformed to colloidal silver nanoparticles during the catalytic reaction. The Si–Si/Si–O dehydrocoupling of 1 with AgNO3 even at dry nitrogen atmosphere is occurred, supporting that the oxidation of NO3−
ion to NO2 is only the possible oxygen source, but not from the adventitious moisture in air. α-, β-, and γ-Cyclodextrins considerably deteriorated the dehydrocoupling of 1 probably due to both the formation of insoluble inclusion complexes
in toluene and the encapsulation of SiH2 moiety. The resulting silole polymer 2 emits green light at 520 nm and is electroluminescent at 520 nm.
Stress Behavior of FCC Metallic Thin Films During Thermal Evaporation
Authors: Ryu Sang , Lee Kyungchun , Ma Seungwhan , Kim Youngman
Published: December 2007

The development of stress in metallic thin films, monitored by in-situ curvature measurements during deposition, is analyzed. Three distinct stress regions including initial compressive, broad tensile, and incremental compressive stress were reported in terms of the film thickness
(deposition time) by F. Spaepen. An experimental set-up was assembled for the in-situ curvature measurements utilizing vacuum thermal evaporation and multi-beam laser reflection points arrayed in x- and y-axis. The change in the spacing of laser reflected points was converted
to the curvature of specimen, in turn, to instantaneous stress levels in the growing films using Stoney's formula. To investigate the effect on the distinct stress regions, the flux of the depositing metallic atoms was used as an experimental variable in this study. For the lowest flux cases
for Cu and Ag, an additional second compressive stress stages after tensile maximum stress was observed in this study. Initial compressive part and tensile maximum stress regions appeared in shorter period of time for the thin films deposited at higher flux of atoms. Thus the flux of depositing
atoms may affect the mechanisms of each stage. The initial compressive stress is conjectured to stem from the state of thin film surfaces; dynamic and relaxed surface. Abroad tensile region is reported from the fact that the reduction of excess volume associated with grain boundaries and/or
the coalescence of grains for high mobility materials. The incremental compressive stress region may be related to surface state and atomic mobilities.
Effect of the On/Off Cyclic Modulation Time Ratio of C2H2/H2 Flow on the Low Temperature Deposition of Carbon Nanofilaments
Authors: Kim Kwang-Duk , Kim Sung-Hoon , Kim Nam Seok , Kim Dong-Uk
Published: December 2007

Low temperature (less than 600 °C) deposition of carbon nanofilaments (CNFs) could be achieved on the silicon oxide substrate by thermal chemical vapor deposition system. We used Fe(CO)5 as the catalyst precursor for CNFs formation. For the enhancement of CNFs formation
density, the source gas flow was intentionally manipulated as the cyclic on/off modulation of C2H2/H2 flow during the initial deposition stage. The CNFs formation density on silicon oxide substrate could be much enhanced by the cyclic modulation process having
the higher growing/etching time ratio (180/30 s). Furthermore, the lattice structures of CNFs developed into carbon nanotubes at the higher growing/etching time ratio (180/30 s) case. The solely hydrogen gas feeding (C2H2 flow off) time during the initial deposition stage
seems to play an important role for the variation in the CNFs formation characteristics by the cyclic modulation process.
Multi-Encoded Rugate Porous Silicon as Nerve Agents Sensors
Authors: Jang Seunghyun , Kim Jihoon , Koh Youngdae , Ko Young Chun , Woo Hee-Gweon , Sohn Honglae
Published: December 2007

The nanostructured rugate porous silicons (PSi) containing multiple photonic band gaps have been generated by an electrochemical etching through applying a composite waveform summed three computer-generated pseudo-sinusoidal current waveforms. They exhibit three sharp photonic band
gaps in the optical reflectivity spectrum, corresponding to the each of the sine components varied from 0.42, 0.36, and 0.30 Hz, with a spacing of 0.06 Hz between each sine component. The sensing experiments using multi-encoded rugate PSi for the detection of nerve agents such as triethyl
phosphate (TEP), diethyl chlorophosphate (DCP), dimethyl methylphosphonate (DMMP), and diethyl ethylphosphonate (DEEP) have been achieved. Capillary condensation in the pores causes the reflectivity of rugate PSi to shift to longer wavelengths due to an increase in refractive indices of the
porous medium.