bluuebunny/crossref_metadata_2025 huggingface dataset:
Short‐and Long‐term Efficacy of Electroconvulsive Therapy for Late‐life Depression: A Pilot Study
Authors: Awata Shuichi , Suzuki Kazumasa , Matsuoka Hiroo
Published: August 2007

Background: Electroconvulsive therapy (ECT) is often administered among the elderly, who are particularly likely to have concurrent medical conditions and medication intolerance.

Objective: To examine the short‐and long‐term efficacy of ECT for late‐life depression, we performed a two‐phase, prospective, naturalistic follow‐up study that compared treatment outcome in old‐aged with that in middle‐aged subjects.

Methods:Phase I study: Twenty‐one subjects who were consecutively referred for ECT, aged at least 50 years, and met the DSM‐IV criteria for a major depressive episode were enrolled. Before ECT, severity of concurrent medical conditions was assessed with the cumulative illness rating scale (CIRS). Before and after a course of ECT, the severity of depressive symptoms was evaluated with the 17‐item Hamilton rating scale for depression (HAM‐D).Phase II study: Seventeen subjects who responded to an acute ECT course in the phase I study were enrolled. Various continuation medications were administered, and symptoms were monitored and evaluated with the HAM‐D for 24 weeks or until relapse.

Results: Overall the subjects had an 81 % short‐term response rate and a 47% relapse rate within 24 weeks after ECT. Response and relapse rates were not significantly different between the middle‐and old‐aged groups (response rates: 91% vs. 70%; relapse rates: 40% vs. 57%). However, the old‐aged patients had higher post‐ECT HAM‐D scores than the middle‐aged patients did (P<0.05), and CIRS scores positively correlated with post‐ECT HAM‐D scores (P<0.05). Relapsers tended to have higher CIRS scores than non‐relapsers did (P=0.06).

Conclusion: In late‐life depression, the short‐term response rate to ECT is considerably good, but the relapse rate was relatively high. Clinicians need to take into consideration the age of patient and any concurrent medical conditions, when planning long‐term management of residual depressive symptoms and prevention of relapse after an initial good response to ECT.
A Psychopathological Study on Elderly Japanese Delusional Depressives in Relation to Collapse of Traditional Japanese Culture
Authors: Hirosawa Masataka , Nagata Toshihiko , Arai Heii
Published: August 2007

Background: Since Japanese society is rapidly being “westernized”, particularly among younger generations who stress individualism, elderly Japanese people who have the traditional values of stressing the maintenance of interpersonal harmony and the suppression of one's feelings might experience strong psychological stress. The incidence of depression seems to be increasing among them. Careful examination of specific contents of thoughts of Japanese elderly depressives, considering the cultural background, may be valuable to understanding their psycho‐pathology.

Methods and Cases: Six inpatients with severe delusional depression who seemed to have accepted the changes in values were selected from 88 elderly inpatients with depression who were admitted to Juntendo Koshigaya Hospital and the contents of their delusional thoughts were analyzed from the psychopathological and psychosocial viewpoints. For our study to be more meaningful, one inpatient from another hospital with characteristics similar to those of the six patients was also studied.

Results: Despite being outwardly westernized, contents of their delusional thoughts seemed to be associated with the traditional Japanese culture in which the family unit took precedence over the individual and interpersonal relationship in the village were regarded as important. Their characteristic delusional thoughts of exclusion from the village were considered to indicate a loss of self‐existence and existential connection with all things, leading them to have delusions of negation. A further examination of their statements expressed in the course of remission revealed that their westernized way of life was actually a pseudo adaptation to the changes in culture and that it was made possible by a sense of “enryo” (modesty and respect of others) and “gaman” (suppressed anger and emotion) towards younger generations, thus concealing their traditional values.

Conclusions: The present survey suggests that even those who have apparently adapted themselves to changes in culture may experience psychological stress and that paying particular attention to their concealed traditional values seems important in preventing elderly Japanese people from suffering depression and in treating elderly Japanese depressives.
Circumstances Related to Falls in the Dementia Special Care Unit of Geriatric Care Facility in Japan
Authors: Nakagawa Yasushi , Maki Satoshi , Yamanaka Takeharu , Ogomori Koji , Ichimiya Atsushi , Nakagawa Chiyuki , Maki Takeshi , Tashiro Nobutada
Published: August 2007

Background: Elderly people with dementia are liable to fall. Herein we report the circumstances of falls in the dementia special care unit of the geriatric care facility “Assist Sakuradai” of Maki psychiatric hospital during the eight months from August 1, 1999 to March 31, 2000.

Methods: The participants were 61 patients admitted to our dementia special care unit. The diagnosis of dementia was based on DSM‐IV criteria. Cognitive impairment was assessed with Folstein's Mini‐Mental State Examination (MMSE) and the revised version of Hasegawa's dementia scale (HDS‐R). The evaluation of activity of daily living was assessed with Nishimura's activity of daily living scale (N‐ADL). Information related to falls was obtained from incident reports.

Results: Forty‐one percent (n=25) of patients (n=61) suffered falls and a total of 69 falls were recorded at the dementia special care unit during the period. Mean scores ± SD (P value using the Mann‐Whitney test) of N‐ADL, HDS‐R, and MMSE for fallers vs. nonfallers were 25.1 ± 8.09 vs. 31.0 ± 9.33 (P=0.013), 8.72 ± 6.88 vs. 8.92 ± 6.67 (P=0.90) and 11.8 ± 7.28 vs. 11.4 ± 5.95 (P=0.747), respectively. Falling accidents occurred most often in the hall (n=34, 49%, P<0.01) and most in association with walking or transferring (n=29, 42%, P<0.01) at our dementia special care unit. The falling accident rate was defined as falls/time/number of staff and was ranked in the order of the greatest number of falls in specific time frames, as follows; 19:30–20:15 (1.8), 20:15–8:00 (1.02), 16:50–19:00 (0.81), 12:30–16:30 (0.50), 9:00–12:30 (0.41), and 8:15–9:00 (0.11).

Conclusion: Our data suggest that the patients with low N‐ADL, patients who use the hall, or patients who were walking or transferring are the most liable to fall and that we should pay intense attention to the working hours between 19:30 and 8:00.
The Influence of the Stroop Interference Effect on an Event‐based Prospective Memory Task in Alzheimer's Disease Patients
Authors: Nakaaki Shutaro , Watanabe Hama , Nakamura Hikaru , Yoshida Shinichi , Matui Teruo , Kinoshita Yoshihiro , Furukawa Toshiaki
Published: August 2007

Background: Prospective memory is known as the memory of a plan to carry out an intended action in the future. Although it is associated with many activities in everyday life, to date there have been no well controlled laboratory studies of prospective memory in patients with Alzheimer's dementia (AD). In this study, we investigated the ability of prospective memory in AD subjects using an event‐based prospective memory task in which prospective remembering is triggered by a specific external cue.

Methods: Using a personal computer, we conducted event‐based prospective memory tasks embedded in the Stroop task. The concurrent cognitive task such as the Stroop task was called the ongoing task. In the event‐based prospective memory task, subjects were required to react by pressing a mouse key whenever a stimulus during the Stroop task (identification of the name of a color printed in black, of the correct color of a colored circle, or the name of a color printed in an incorrect color) appeared in a larger‐than‐normal size. This target stimulus was designed to appear eight times in each condition, i.e., word condition, color condition, and incorrect‐color condition, during the Stroop task.

Results: Normal elderly people showed good event‐based prospective memory performance across all three conditions in the Stroop task. In contrast, AD subjects performed poorly in the event‐based prospective memory task under the incorrect‐color condition in the Stroop task.

Conclusion: This study indicated that an ongoing concurrent task with a high attention demand affects the performance of event‐based prospective memory in AD subjects. The performance of event‐based prospective memory in AD subjects was more sensitive to the Stroop interference effect observed in the ongoing task than in normal elderly people. The breakdown of this event‐based prospective memory may reflect the limited attention capacity of AD subjects.
Repetition Priming in Dementia of Alzheimer's Type in Japanese
Authors: Motomura Naoyasu , Tomota Yoji , Seo Takashi
Published: August 2007

Background: Memory is profoundly impaired in patients with dementia of Alzheimer's type (DAT). However, the study of priming, which is thought to be implicit memory, is relatively scarce in DAT. In Japan there is only one study, which investigated repetition priming in DAT and the relationship between the severity of dementia and repetition priming in DAT has never been examined. Therefore, we studied repetition priming in patients with various severity of DAT from the standpoint of familiarity of words.

Method: A new repetition priming task, which is constructed of 3 syllable Japanese Kana nouns and which contains high familiarity words and low familiarity words according to Chihara was used for an implicit memory task. The task was carried out by normal controls and patients with DAT. Each group was matched by age, sex, and educational level.

Results: A clear repetition priming effect was found among the control and dementia groups both in low and high familiarity words. The priming effects of a high familiarity task demonstrated no statistical differences among the control and dementia group. However, the priming effect of the low familiarity task in the severe dementia group was revealed to be significantly low compared with that of the control group (p<0.01), mild (p<0.01) and moderate group (p<0.05), and there was also statistical significance between the normal control and moderate dementia group (p<0.05).

Conclusion: These results indicate that dementia severity and word familiarity influences repetition priming in DAT.
Flash Visual Evoked Potentials of Various Derivations in Dementia of the Alzheimer Type and Vascular Dementia
Authors: Sakai Nami
Published: August 2007

Background: Recently, evoked potentials have been used for objective monitoring of the cortical function in dementia. The aim of this study was to distinguish dementia of the Alzheimer type (DAT) from vascular dementia (VaD) using flash visual evoked potentials of various derivations.

Methods: A total of 70 patients consulting Tachikawa Medical Center Kashiwazaki Kosei Hospital were divided into four groups, normal adult (29.5 ± 8.5 years, n=16), normal elderly (77.2 ± 4.7 years, n=17), VaD (81.1 ± 8.1 years, n=17) and DAT (77.4 ± 5.6 years, n=20). Red flash stimulation was provided by a pair of goggles. Visual evoked potentials (VEPs) to flash were recorded in accordance with the International 10–20 Electrode System.

Results: The latencies of N130 and P190 of frontal and central derivations were significantly reduced in DAT compared with all other groups (p<0.05). The N130 and P190 latencies were markedly delayed in the normal elderly group compared with the normal adult group (p<0.05). The P3 (P100) latency of occipital derivation was significantly delayed in normal elderly, VaD and DAT groups compared with the normal adult group (p<0.05). In the DAT group, the P190 latency was shortened at central and frontal derivations compared with that at occipital derivation (p<0.05).

Conclusions: The N130 and P190 latencies decreased at frontal and central derivations in DAT. While the reason is still unclear, dysfunction in the central visual system induced by the degeneration of neuronal populations in DAT may cause the apparently reduced latency. Flash VEPs of frontal and central derivations may be useful for the differential diagnosis of DAT from VaD.
Effect of Sildenafil Citrate (Viagra) on Coronary Flow in Normal Subjects
Authors: Ishikura Fuminobu , Beppu Shintaro , Ueda Hiroaki , Nehra Ajay , Khandheria Bijoy K.
Published: August 2007

Background: The purpose of this study was to evaluate the effect of sildenafil citrate (Viagra) on coronary function in normal subjects. Methods: The study assessed mean blood pressure, left anterior descending coronary artery (LAD) flow, and echocardiographic variables before and 30 and 60 minutes after taking 50 mg of sildenafil citrate. The mean velocity of LAD flow was assessed with Doppler flow imaging. The study subjects were 6 healthy male volunteers (mean age 37 years). Results: The mean velocity of LAD flow increased 60 minutes after taking sildenafil citrate, but there were no other changes. Two volunteers felt mild flashing and one had mild headache during the study. Conclusion: Sildenafil citrate caused vasodilatation in a normal coronary artery without systemic pressure drops. These results suggest that the agent itself did not have negative effects on the heart in normal subjects.
Measurement of Condensation Heat Transfer Coefficients at Near-Critical Pressures in Refrigerant Blends
Authors: Jiang Yirong , Mitra Biswajit , Garimella Srinivas , Andresen Ulf C.
Published: August 2007

This paper presents the results of an experimental study on condensation heat transfer of refrigerant blends R404A and R410A flowing through horizontal tubes of 9.4 and 6.2mm inner diameter at nominal pressures of 80% and 90% of the critical pressure. Local heat transfer coefficients were measured for the mass flux range 200<G<800kg∕m2‐s in small quality increments over the entire vapor-liquid region. Heat transfer coefficients increased with quality and mass flux, while the effect of reduced pressure was not very significant within this range of pressures. The heat transfer coefficients increased with a decrease in diameter.
High Performance and Subambient Silicon Microchannel
Cooling
Authors: Colgan E. G. , Furman B. , Gaynes M. , LaBianca N. , Magerlein J. H. , Polastre R. , Bezama R. , Marston K. , Schmidt R.
Published: August 2007

High performance single-phase Si microchannel coolers have been designed and characterized in single chip modules in a laboratory environment using either water at 22°C or a fluorinated fluid at temperatures between 20 and −40°C as the coolant. Compared to our previous work, key performance improvements were achieved through reduced channel pitch (from 75 to 60 microns), thinned channel bases (from 425 to 200 microns of Si), improved thermal interface materials, and a thinned thermal test chip (from 725 to 400 microns of Si). With multiple heat exchanger zones and 60 micron pitch microchannels with a water flow rate of 1.25lpm, an average unit thermal resistance of 15.9Cmm2∕W between the chip surface and the inlet cooling water was demonstrated for a Si microchannel cooler attached to a chip with Ag epoxy. Replacing the Ag epoxy layer with an In solder layer reduced the unit thermal resistance to 12.0Cmm2∕W. Using a fluorinated fluid with an inlet temperature of −30°C and 60 micron pitch microchannels with an Ag epoxy thermal interface layer, the average unit thermal resistance was 25.6Cmm2∕W. This fell to 22.6Cmm2∕W with an In thermal interface layer. Cooling >500W∕cm2 was demonstrated with water. Using a fluorinated fluid with an inlet temperature of −30°C, a chip with a power density of 270W∕cm2 was cooled to an average chip surface temperature of 35°C. Results using both water and a fluorinated fluid are presented for a range of Si microchannel designs with a channel pitch from 60 to 100 microns.
Heat Transfer Enhancement of Steam Reformation by Passive Flow Disturbance Inside the Catalyst Bed
Authors: Erickson Paul Anders , Liao Chang-Hsien
Published: August 2007

Because of the potential for high efficiency and low emissions, hydrogen powered systems are considered to be the next generation power source for both stationary and transportation applications. Providing a hydrogen source is a critical challenge. Steam reforming processes are demonstrated for producing hydrogen for fuel cell and other applications. Generating hydrogen via steam reformation requires that heat energy be transferred to the reactants to support the endothermic reaction. For a cylindrical steam-reforming reactor, large thermal gradients between the heat source (reactor wall) and reactor centerline create a nonideal condition for complete conversion. This gradient is caused by insufficient heat transfer inside the catalyst bed. Passive flow disturbance inside the catalyst bed is a potential method to enhance the heat and mass transfer in the steam-reforming process. This paper presents experimental research that investigates the effect of changing the flow pathway inside the reactor to improve the heat and mass transfer and thus enhance fuel conversion. Based on the experimental results, a 14% increase of methanol fuel conversion was achieved via the passive flow disturbance enhancement. The tradeoff was an extra pressure drop of 2.5 kPa across the reactor. A 30 h experimental run does not show a significant change in degradation rate for the passive flow disturbance. The results of this study contribute to the improvement of reformer design for better fuel processing system performance.
Aspect Ratio Effect on Natural Convection Flow in a Cavity Submitted to a Periodical Temperature Boundary
Authors: Cheikh Nader Ben , Beya Brahim Ben , Lili Taieb
Published: August 2007

The effect of aspect ratio on natural convection flow in a cavity submitted to periodic temperature boundary, is investigated numerically. The temperature of the heated wall is either maintained constant or varied sinusoidally with time while the temperature of the opposite vertical wall is maintained constant. The results are given for a range of varied parameters as Rayleigh number (5×103⩽Ra⩽106), cavity aspect ratio (1∕6⩽A⩽8), and period of the sinusoidally heated wall (1⩽τ⩽1600). The amplitude of oscillation (a=0.8) and the Prandtl number (Pr=0.71) were kept constant. The results obtained in the steady state regime show that the heat transfer averaged over the cold wall is maximum when the aspect ratio is in the range 1⩽A⩽2. In the case of a periodic temperature boundary, it is shown that the deviation between the mean heat transfer and the heat transfer of the constant heated case is larger for shallow cavities.
Spray Cooling of High Aspect Ratio Open Microchannels
Authors: Coursey Johnathan S. , Kim Jungho , Kiger Kenneth T.
Published: August 2007

Direct spraying of dielectric liquids has been shown to be an effective method of cooling high-power electronics. Recent studies have illustrated that even higher heat transfer can be obtained by adding extended structures, particularly straight fins, to the heated surface. In the current work, spray cooling of high-aspect-ratio open microchannels was explored, which substantially increases the total surface area and allows more residence time for the incoming liquid to be heated by the wall. Five such heat sinks were constructed, and their thermal performance was investigated. These heat sinks featured a projected area of 1.41×1.41cm2, channel width of 360μm, a fin width of 500μm, and fin lengths of 0.25mm, 0.50mm, 1.0mm, 3.0mm, and 5.0mm. The five enhanced surfaces and a flat surface with the same projected area were sprayed with a full cone nozzle using PF-5060 at 30°C and nozzle pressure differences from 1.36–4.08atm(69–121ml∕min). In all cases, the enhanced surfaces improved thermal performance compared to the flat surface. Longer fins were found to outperform shorter ones in the single-phase regime. Adding fins also resulted in the onset of two-phase effects (and higher-heat transfer) at lower wall temperatures than the flat surface. The two-phase regime was characterized by a balance between added area, changing flow flux, flow channeling, and added conduction resistance. Spray efficiency calculations indicated that a much larger percentage of the liquid sprayed onto the enhanced surface evaporated than with the flat surface. Fin lengths between 1mm and 3mm appeared to be optimum for heat fluxes as high as 124W∕cm2 (based on projected area) and the range of conditions studied.
Determination of the Sensitivity of Heat Transfer Systems Using Global Sensitivity and Gaussian Processes
Authors: Emery A. F. , Bardot D.
Published: August 2007

A critical aspect of the design of systems or experiments is a sensitivity analysis to determine the effects of the different variables. This is usually done by representing the response by a Taylor series and evaluating the first-order derivatives at a nominal operating point. When there is uncertainty about the operating point, the common approach is the construction of a response surface and Monte Carlo sampling based on the probability distribution of these uncertain variables. Because of the expense of Monte Carlo sampling, it is important to restrict the analysis to those variables to which the response is most sensitive. Identification of the most sensitive parameters can be conveniently done using Global sensitivity, which both defines the most critical variables and also quantifies the effects of interacting variables. This also can be a computationally expensive process and, for complex models, is generally prohibitively expensive. A solution is the use of Gaussian processes that allows one to create a response surface using easy-to-evaluate functions. This paper describes the use of these ideas for a heat transfer problem.
A Mathematical Model for Heat and Mass Transfer in Methane-Air
Boundary Layers With Catalytic Surface Reactions
Authors: Tong T. W. , Abou-Ellail M. M. M. , Li Y.
Published: August 2007

Catalytic combustion of hydrocarbon mixtures involves the adsorption of the fuel and oxidant into a platinum surface, chemical reactions of the adsorbed species, and the desorption of the resulting products. Re-adsorption of some produced gases is also possible. The catalytic reactions can be beneficial in porous burners that use low equivalence ratios. In this case, the porous burner flame can be stabilized at low temperatures to prevent any substantial gas emissions, such as nitric oxide. The present paper is concerned with the numerical computation of heat transfer and chemical reactions in flowing methane-air mixtures over a platinum coated hot plate. Chemical reactions are included in the gas phase and in the solid platinum surface. In the gas phase, 16 species are involved in 49 elementary reactions. On the platinum hot surface, additional surface species are included that are involved in 24 additional surface chemical reactions. The platinum surface temperature is fixed, while the properties of the reacting flow are computed. The flow configuration investigated here is the parallel boundary layer reacting flow. Finite-volume equations are obtained by formal integration over control volumes surrounding each grid node. Up-wind differencing is used to ensure that the influence coefficients are always positive to reflect the physical effect of neighboring nodes on a typical central node. The finite-volume equations are solved iteratively for the reacting gas flow properties. On the platinum surface, surface species balance equations, under steady-state conditions, are solved numerically by an under-relaxed linear algorithm. A non-uniform computational grid is used, concentrating most of the nodes near the catalytic surface. Surface temperatures, 1150 K and 1300 K, caused fast reactions on the catalytic surface, with very slow chemical reactions in the flowing gas. These slow reactions produce mainly intermediate hydrocarbons and unstable species. The computational results for the chemical reaction boundary layer thickness and mass transfer at the gas-surface interface are correlated by non-dimensional relations, taking the Reynolds number as the independent variable. Chemical kinetic relations for the reaction rate are obtained which are dependent on reactants’ concentrations and surface temperature.
Direct Numerical Simulation of a Non-Premixed Impinging Jet Flame
Authors: Jiang Xi , Zhao Hua , Luo Kai H.
Published: August 2007

A non-premixed impinging jet flame at a Reynolds number 2000 and a nozzle-to-plate distance of two jet diameters was investigated using direct numerical simulation (DNS). Fully three-dimensional simulations were performed employing high-order numerical methods and high-fidelity boundary conditions to solve governing equations for variable-density flow and finite-rate Arrhenius chemistry. Both the instantaneous and time-averaged flow and heat transfer characteristics of the impinging flame were examined. Detailed analysis of the near-wall layer was conducted. Because of the relaminarization effect of the wall, the wall boundary layer of the impinging jet is very thin, that is, in the regime of viscous sublayer. It was found that the law-of-the-wall relations for nonisothermal flows in the literature need to be revisited. A reduced wall distance incorporating the fluid dynamic viscosity was proposed to be used in the law-of-the-wall relations for nonisothermal flows, which showed improved prediction over the law of the wall with the reduced wall distance defined in terms of fluid kinematic viscosity in the literature. Effects of external perturbation on the dynamic behavior of the impinging flame were found to be insignificant.
A New Finite-Conductivity Droplet Evaporation Model Including Liquid Turbulence Effect
Authors: Balasubramanyam M. S. , Chen C. P. , Trinh H. P.
Published: August 2007

A new approach to account for finite thermal conductivity and turbulence effects within atomizing droplets of an evaporating spray is presented in this paper. The model is an extension of the T-blob and T-TAB atomization/spray model of Trinh and Chen [Atomization and Sprays, 16(6), pp. 907–932]. This finite conductivity model is based on the two-temperature film theory in which the turbulence characteristics of the droplet are used to estimate the effective thermal diffusivity for the liquid-side film thickness. Both one-way and two-way coupled calculations were performed to investigate the performance of this model against the published experimental data.
Thermal Conductivity of Single-Walled Carbon Nanotube/PMMA Nanocomposites
Authors: Guthy Csaba , Du Fangming , Brand Stijn , Winey Karen I. , Fischer John E.
Published: August 2007

Single-walled carbon nanotubes (SWNTs) are considered as promising filler materials for improving the thermal conductivity of conventional polymers. We carefully investigated the thermal conductivity of SWNT poly(methylmethacrylate) (PMMA) nanocomposites with random SWNT orientations and loading up to 9vol% using the comparative technique. The composites were prepared by coagulation and exhibit ∼250% improvement in the thermal conductivity at 9vol%. The experimental results were analyzed using the versatile Nielsen model, which accounts for many important factors, including filler aspect ratio and maximum packing fraction. In this work, the aspect ratio was determined by atomic force microscopy (AFM) and used as an input parameter in the Nielsen model. We obtained good agreement between our results and the predictions of the Nielsen model, which indicates that higher aspect ratio fillers are needed to achieve further enhancement. Our analysis also suggests that improved thermal contact between the SWNT network and the matrix material would be beneficial.
Nusselt Number Correlations for Turbulent Natural Convection Flows Using Asymptotic Analysis of the Near-Wall Region
Authors: Balaji C. , Hölling M. , Herwig H.
Published: August 2007

In this paper, we propose a general methodology by which a universal temperature profile, derived by matching temperature gradients in the overlap region of the wall layer and the core layer, that is valid for high Rayleigh number flows, can be recast into a correlation for the Nusselt number. We then evaluate its adequacy for three types of flows: (a) fully developed flows (e.g., the infinite channel), (b) developing flows (e.g., the vertical flat plate boundary layer), and (c) complex flows (e.g., Rayleigh-Bénard convection and the differentially heated square cavity). The correlation for the Nusselt number, in general, contains a logarithmic term, usually missing in earlier studies, with which we are able to match existing direct numerical simulations or experimental data very well for both fully developed and complex flows.
Soil organic carbon dynamics along a climatic gradient in a southern Appalachian spruce–fir forest
Authors: Tewksbury C.E. , Van Miegroet H.
Published: August 2007

A field study was conducted in a high-elevation spruce–fir ( Picea rubens Sarg. – Abies fraseri (Pursh.) Poir) forest in the Great Smoky Mountains National Park to assess the effect of temperature on soil C storage and dynamics. In eight plots along an elevation gradient (1500–1900 m), we measured soil temperature, forest floor and mineral soil C, litter decomposition, soil respiration, and forest floor mean residence time. Mean annual soil temperature and annual degree-days above 5 °C were inversely correlated with elevation. Total soil C (166–241 Mg·ha–1) showed no trend with elevation, while forest floor C accumulation (16.3–35.9 Mg·ha–1) decreased significantly with elevation. Carbon dynamics did not follow a consistent elevation pattern; however, the cooler upper elevations showed the lowest C turnover as indicated by the lowest needle decomposition rate (k = 0.0231·year–1) and the longest mean residence time of forest floor C (22 years). Mean annual CO2efflux from the soil (1020–1830 kg C·ha–1·year–1) was negatively correlated with mean annual soil temperatures and annual degree-days above 5 °C. This gradient study offers useful insights into C release patterns under future warming scenarios, and suggests that the highest elevation may be most susceptible to global warming.
IS MODIFIED CHAPLYGIN GAS ALONG WITH BAROTROPIC FLUID RESPONSIBLE FOR ACCELERATION OF THE UNIVERSE?
Authors: CHAKRABORTY WRITAMBHARA , DEBNATH UJJAL
Published: August 2007

In this letter, we consider a model of the universe filled with modified Chaplygin gas and another fluid (with barotropic equation of state) and its role in accelerating phase of the universe. We have assumed that the mixture of these two fluid models is valid from (i) the radiation era to ΛCDM for -1 ≤ γ ≤ 1 and (ii) the radiation era to quintessence model for γ < -1. For these two fluid models, the statefinder parameters describe different phase of the evolution of the universe.
PROPER MATTER COLLINEATIONS OF PLANE SYMMETRIC SPACETIMES
Authors: SHARIF M. , ISMAEEL TARIQ
Published: August 2007

We investigate matter collineations of plane symmetric spacetimes when the energy–momentum tensor is degenerate. There exists three interesting cases where the group of matter collineations is finite-dimensional. The matter collineations in these cases are either four, six or ten in which four are isometries and the rest are proper.
THE QCD PARTON MODEL: A USEFUL APPROXIMATION
Authors: DI SALVO ELVIO
Published: August 2007

Approximate relations among transverse momentum dependent quark distribution functions are established in the framework of the QCD parton model. The validity of such results survives QCD evolution effects, owing to the Politzer theorem on equations of motion. Furthermore the model fixes an energy scale, involved in the parametrization of the correlator, which determines the Q2 dependence of the azimuthal asymmetries in inclusive reactions. Some of the present data — in particular the sin 2ϕ single spin asymmetry in semi-inclusive deep inelastic scattering (SIDIS) and the cos ϕ asymmetry in unpolarized SIDIS — support model predictions. Further measurements of SIDIS and Drell–Yan asymmetries are suggested, in particular the SIDIS double spin asymmetry, which allows to determine approximately the proton transversity.
OPERATOR ORDERING IN TWO-DIMENSIONAL N = 1 SUPERSYMMETRY WITH CURVED MANIFOLD
Authors: MOTOYUI NOBUYUKI , YAMADA MITSURU
Published: August 2007

We investigate an operator ordering problem in two-dimensional N = 1 supersymmetric model which consists of n real superfields. There arises an operator ordering problem when the target space is curved. We have to fix the ordering in quantum operator properly to obtain the correct supersymmetry algebra. We demonstrate that the super-Poincaré algebra fixes the correct operator ordering. We obtain a supercurrent with correct operator ordering and a central extension of supersymmetry algebra.
CORRIDOR-SCENE CLASSIFYING METHODS FOR MOBILE ROBOT BASED ON MULTI-SONAR-SENSOR INFORMATION FUSION
Authors: WANG XIUQING , HOU ZENG-GUANG , CHENG LONG , TAN MIN , ZHU FEI
Published: August 2007

The ability of cognition and recognition for complex environment is very important for a real autonomous robot. A new scene analysis method using kernel principal component analysis (kernel-PCA) for mobile robot based on multi-sonar-ranger data fusion is put forward. The principle of classification by principal component analysis (PCA), kernel-PCA, and the BP neural network (NN) approach to extract the eigenvectors which have the largest k eigenvalues are introduced briefly. Next the details of PCA, kernel-PCA and the BP NN method applied in the corridor scene analysis and classification for the mobile robots based on sonar data are discussed and the experimental results of those methods are given. In addition, a corridor-scene-classifier based on BP NN is discussed. The experimental results using PCA, kernel-PCA and the methods based on BP neural networks (NNs) are compared and the robustness of those methods are also analyzed. Such conclusions are drawn: in corridor scene classification, the kernel-PCA method has advantage over the ordinary PCA, and the approaches based on BP NNs can also get satisfactory results. The robustness of kernel-PCA is better than that of the methods based on BP NNs.
AN INTELLIGENT SOFT MEASUREMENT METHOD FOR PREDICTING PARAMETERS
Authors: LIU ZAIWEN , WANG XIAOYI , CUI LIFENG
Published: August 2007

An intelligent soft measurement and information processing method for predicting parameters of process control system was proposed. Process neural network (PNN) is a new configuration of artificial neural network put forward in recent years. Some algorithms of PNN were discussed, and these algorithms were based on function orthogonal basis expansion, yet the convergence rate was comparatively low. An improved algorithm for raising training speed based on function orthogonal basis expansion in PNN for soft measurement was researched. After increasing the normalizing rule on the original algorithm, and introducing function momentum adjustment item and learning rate automatically adjustment method for network weight function, the training time of learning algorithm for PNN was reduced, and a good result was represented by simulation in wastewater treatment system.
APPROACH OF MULTIPLE MOVING TARGETS DETECTION FOR MICROWAVE SURVEILLANCE SENSORS
Authors: WANG WENQIN
Published: August 2007

Multiple moving targets detection is one of the fundamental problems in information acquisition. In this paper, the use of a transformable period and symmetrical linear frequency modulated (TPS-LFM) waveform for microwave surveillance sensor multiple moving targets identification, is proposed. In order to accurately estimate target's true position and velocity, a relatively unknown yet powerful technique, the so-called fractional Fourier transform (FrFT), is applied to estimate the moving target parameters. By mapping a target's signal onto a fractional Fourier axis, the FrFT permits a constant-velocity target to be focused in the fractional Fourier domain thereby affording orders of magnitude improvement in signal-clutter-ratio. Moving target velocity and position parameters are derived and expressed in terms of an optimum fractional angle and a measured fractional Fourier position, allowing a target to be accurately located. Moreover, to resolve the problem whereby weak targets are covered by the sidelobes of strong ones, the CLEAN technique is also applied. Simulation results show that the method is effective in estimating target velocity and position parameters for microwave surveillance sensors.
MULTI-RESOLUTION CROWD DENSITY ESTIMATION BASED ON TEXTURE ANALYSIS AND LEARNING FROM DEMONSTRATION
Authors: LIANG GUOYUAN , LEE KA KEUNG , XU YANGSHENG
Published: August 2007

Crowd density estimation is very important for intelligent surveillance systems in public places. This paper presents an automatic method of estimating crowd density using texture analysis and machine learning. First the crowd scene is modeled as a series of multi-resolution image cells based on perspective projection. The cell size is normalized to obtain a uniform representation of texture features. Then the feature vectors of textures are extracted from each input image cell and the support vector machine (SVM) method is utilized to solve the regression problem for calculating the crowd density. In order to diminish the instability of texture feature measurements, a technique of searching the extrema in the Harris–Laplacian space is applied. Finally, the SVM method is used again to detect some abnormal situations caused by the changes in density distribution. Experiments on real crowd videos show the effectiveness of the proposed system.
Acylation-stimulating protein/C5L2-neutralizing antibodies alter triglyceride metabolism in vitro and in vivo
Authors: Cui Wei , Paglialunga Sabina , Kalant David , Lu HuiLing , Roy Christian , Laplante Mathieu , Deshaies Yves , Cianflone Katherine
Published: August 2007

Acylation-stimulating protein (ASP), a lipogenic hormone, stimulates triglyceride (TG) synthesis and glucose transport upon activation of C5L2, a G protein-coupled receptor. ASP-deficient mice have reduced adipose tissue mass due to increased energy expenditure despite increased food intake. The objective of this study was to evaluate the blocking of ASP-C5L2 interaction via neutralizing antibodies (anti-ASP and anti-C5L2-L1 against C5L2 extracellular loop 1). In vitro, anti-ASP and anti-C5L2-L1 blocked ASP binding to C5L2 and efficiently inhibited ASP stimulation of TG synthesis and glucose transport. In vivo, neither anti-ASP nor anti-C5L2-L1 altered body weight, adipose tissue mass, food intake, or hormone levels (insulin, leptin, and adiponectin), but they did induce a significant delay in TG clearance [ P < 0.0001, 2-way repeated-measures (RM) ANOVA] and NEFA clearance ( P < 0.0001, 2-way RM ANOVA) after a fat load. After treatment with either anti-ASP or anti-C5L2-L1 antibody there was no change in adipose tissue AMPK activity, but neutralizing antibodies decreased perirenal TG mass (−38.4% anti-ASP, −18.8% anti-C5L2, P < 0.01–0.001) and perirenal LPL activity (−75.6% anti-ASP, −72.5% anti-C5L2, P < 0.05). In liver, anti-C5L2-L1 decreased TG mass (−42.8%, P < 0.05), whereas anti-ASP increased AMPK activity (+34.6%, P < 0.001). In the muscle, anti-C5L2-L1 significantly increased TG mass (+128.0%, P < 0.05), LPL activity (+226.1%, P < 0.001), and AMPK activity (+71.1%, P < 0.01). In addition, anti-ASP increased LPL activity (+164.4, P < 0.05) and AMPK activity (+53.9%, P < 0.05) in muscle. ASP/C5L2-neutralizing antibodies effectively block ASP-C5L2 interaction, altering lipid distribution and energy utilization.
Connective Tissue Growth Factor and Insulin-Like Growth Factor 2 Show Upregulation in Early Growth Plate Radiorecovery Response following Irradiation
Authors: Wang Yan , Zhang Mingliang , Middleton Frank A. , Horton Jason A. , Pritchard Meredith , Spadaro Joseph A. , Farnum Cornelia E. , Damron Timothy A.
Published: August 2007

Introduction: The growth plate response following radiotherapy is poorly understood. In particular, little is known about the changes in growth plate growth factors and cytokines following irradiation. The hypothesis was that a limited number of growth factors and cytokines play a role in growth plate proliferative and hypertrophic chondrocyte radio-recovery. Methods: The right limbs of 6 rats were irradiated (17.5 Gy), leaving the left limbs as controls. Limbs were harvested 1 (n = 3) and 2 (n = 3) weeks later. Microarrays were constructed from chondrocytes obtained by laser microdissection from the proliferative zone (PZ) and the hypertrophic zone (HZ) of normal and irradiated tibia growth plates. Real-time PCR was used to confirm the expression of parathyroid hormone receptor 1 (Pthr1), connective tissue growth factor (CTGF), insulin-like growth factor I receptor (IGF1R), insulin-like growth factor II (IGF2), interleukin 17β (IL17b) and chemokine ligand 12 (CXCL12). Results and Conclusions: IGF2 is upregulated in the PZ and CTGF is upregulated in both the PZ and HZ 1 week after irradiation, prior to the histomorphometric appearance of growth plate recovery in this immature animal radiation model, supporting their role in stimulating early return of the growth plate. By 2 weeks after irradiation, a number of growth factors and cytokines, including CTGF and Pthr1 in both zones, CXCL12 and its receptor in the PZ, and IL17b and bone morphogenetic protein 2 in the HZ, show upregulation, suggesting a possible later role in radiorecovery. The effects of irradiation on Pthr1, CTGF, IGF2 and CXCL12 in PZ and Pthr1, CTGF, IL17b and IGF1R in the HZ determined by microarray and real-time RT-PCR was highly correlated (r = 0.797, p < 0.05 in the PZ and r = 0.875, p < 0.01 in the HZ, respectively).
A Self-Assembled Fibroblast-Endothelial Cell Co-Culture System That Supports in vitro Vasculogenesis by both Human Umbilical Vein Endothelial Cells and Human Dermal Microvascular Endothelial Cells
Authors: Sorrell J. Michael , Baber Marilyn A. , Caplan Arnold I.
Published: August 2007

The construction of vascularized connective tissues is an important goal in tissue engineering in that the presence of a patent bio-engineered vasculature should facilitate vascularization of an implant. Fibroblasts play an essential role in the angiogenic process through their production of extracellular matrix molecules and through their release of essential growth factors. Therefore, the aim of this study is to develop a thin 3-dimensional model in which fibroblasts support endothelial cells in the formation of tube-like structures. Macro- and microvascular endothelial cells were seeded onto confluent lawns of human fibroblasts and were cultured in the presence of high levels of ascorbate 2-phosphate to create a tissue-like structure in which endothelial cell organized into tube-like structures. The process was visualized in the culture dish through labeling of cells with a long-lasting fluorescent vital dye. Intact sheet-like structures were created in which endothelial cell tube-like structures were encased by fibroblasts and were surrounded by a basement membrane. These structures appeared to contain a lumen and remained stable for up to 5 weeks in culture. This culture system provides an in vitro method to study fibroblast-endothelial cell interactions and to study the effects of pro- and anti-angiogenic factors on endothelial cell differentiation. This system also provides an experimental basis for developing vascularized tissue-engineered connective tissue.
Subdural Electrode-Associated Complications: A 20-Year Experience
Authors: Fountas Kostas N. , Smith Joseph R.
Published: August 2007

Background: Implantation of subdural strip and grid electrodes is a common methodology in the invasive evaluation of patients with medically refractory epilepsy. Although their implantation is safe, the occurrence of implantation-associated complications can occasionally be troublesome. Methods: In our current retrospective study, 185 patients undergoing subdural grid/strip implantation for invasive monitoring were examined. Their ages ranged between 16 and 48 years (mean 23.6). AdTech (Racine, Wisc., USA) strip and grid electrodes were implanted under general endotracheal anesthesia in all our cases. Duration of electroencephalographic monitoring ranged from 2 to 25 days (mean 10.8). The follow-up period ranged from 24 to 60 months (mean 44.6 months). Results: The most common complication in our series was the development of postoperative epidural hematoma in 3 patients (1.6%), while 2 patients (1.1%) suffered a subdural hematoma. Two patients (1.1%) developed significant brain edema postoperatively, 2 others (1.1%) developed an infection, while 2 patients (1.1%) experienced transient aphasia. Two patients (1.1%) had fatal outcomes in our series. Interestingly, in 5 patients (2.7%) nonhabitual seizures were recorded. Conclusion: Thorough understanding, early identification and prompt management of potential complications can minimize the risks associated with the implantation of subdural electrodes.
Radiosurgery in Patients with Bilateral Vestibular Schwannomas
Authors: Vachhani Jay A. , Friedman William A.
Published: August 2007

Background: Patients with bilateral vestibular schwannomas offer a unique opportunity to determine the effectiveness of radiosurgery. By using the untreated tumor as an internal control, one can determine whether radiosurgery was able to interrupt the natural history of the treated tumor. Methods: From September 1998 to November 2004, 13 patients with neurofibromatosis type 2 had 14 tumors treated with radiosurgery at the University of Florida. A retrospective analysis was performed on these patients. Actuarial statistics were used to analyze local control in both the treated and untreated tumor. Results: The average follow-up length was 38 months. One patient failed to send a follow-up MRI. Actuarial local control in the treated tumors was 100% at 1 year and 92% at 2 and 5 years. Only 1 of the treated tumors continued to grow. In the untreated tumors, actuarial local control was 100% at 1 year, 78% at 2 years and 21% at 5 years. None of the untreated tumors decreased in size. Conclusion: In all but 1 patient with follow-up data, radiosurgery successfully prevented or reversed tumor growth. Additionally, half of the untreated tumors continued to grow. This study shows that radiosurgery alters the natural history of vestibular schwannomas.
Intracerebral Microvascular Measurements during Deep Brain Stimulation Implantation using Laser Doppler Perfusion Monitoring
Authors: Wårdell Karin , Blomstedt Patric , Richter Johan , Antonsson Johan , Eriksson Ola , Zsigmond Peter , Bergenheim A. Tommy , Hariz Marwan I.
Published: August 2007

The aim of the study was to investigate if laser Doppler perfusion monitoring (LDPM) can be used in order to differentiate between gray and white matter and to what extent microvascular perfusion can be recorded in the deep brain structures during stereotactic neurosurgery. An optical probe constructed to fit in the Leksell® Stereotactic System was used for measurements along the trajectory and in the targets (globus pallidus internus, subthalamic nucleus, zona incerta, thalamus) during the implantation of deep brain stimulation leads (n = 22). The total backscattered light intensity (TLI) reflecting the grayness of the tissue, and the microvascular perfusion were captured at 128 sites. Heartbeat-synchronized pulsations were found at all perfusion recordings. In 6 sites the perfusion was more than 6 times higher than the closest neighbor indicating a possible small vessel structure. TLI was significantly higher (p < 0.005) and the perfusion significantly lower (p < 0.005) in positions identified as white matter in the respective MRI batch. The measurements imply that LDPM has the potential to be used as an intracerebral guidance tool.