bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptive and reliable video transmission over UMTS for enhanced performance
Authors: Alexiou Antonios , Antonellis Dimitrios , Bouras Christos
Published: May 2006

This paper proposes a mechanism for the congestion control for video transmission over universal mobile telecommunications system (UMTS). Our scheme is applied when the mobile user experiences real‐time multimedia content and adopts the theory of a widely accepted rate control method in wired networks, namely equation‐based rate control. In this approach, the transmission rate of the multimedia data is determined as a function of the packet loss rate, the round trip time and the packet size and the server explicitly adjusts its sending rate as a function of these parameters. Furthermore, we examine the performance of the UMTS for real‐time video transmission using real‐time protocols. Through a number of experiments, we measure performance parameters such as end‐to‐end delay, delay in radio access network, delay jitter and throughput in the wireless link. Copyright © 2006 John Wiley & Sons, Ltd.
A location‐aware peer‐to‐peer overlay network
Authors: Wu Chi‐Jen , Liu De‐Kai , Hwang Ren‐Hung
Published: May 2006

This work describes a novel location‐aware, self‐organizing, fault‐tolerant peer‐to‐peer (P2P) overlay network, referred to as Laptop. Network locality‐aware considerations are a very important metric for designing a P2P overlay network. Several network proximity schemes have been proposed to enhance the routing efficiency of existing DHT‐based overlay networks. However, these schemes have some drawbacks such as high overlay network and routing table maintenance overhead, or not being completely self‐organizing. As a result, they may result in poor scalability as the number of nodes in the system grows.

Laptop constructs a location‐aware overlay network without pre‐determined landmarks and adopts a routing cache scheme to avoid maintaining the routing table periodically. In addition, Laptop significantly reduces the overlay maintenance overhead by making each node maintain only the connectivity between parent and itself. Mathematical analysis and simulations are conducted to evaluate the efficiency, scalability, and robustness of Laptop. Our mathematical analysis shows that the routing path length is bounded by logdN, and the joining and leaving overhead is bounded bydlogdN, whereNis the number of nodes in the system, anddis the maximum degree of each node on the overlay tree. Our simulation results show that the average latency stretch is 1.6 and the average routing path length is only about three in 10 000 Laptop nodes, and the maximum degree of a node is bounded by 32. Copyright © 2006 John Wiley & Sons, Ltd.
Performance analysis of resource sharing policies in CDMA networks
Authors: Fodor Gábor
Published: May 2006

We consider an interference‐limited code division multiple access (CDMA) network, in which some of the service classes are explicit rate controlled. Such rate‐controlled service classes include adaptive ones whose holding time does not depend on the sending rate, while the holding time of elastic services becomes longer when their sending rate is slowed down. We develop a Markov model that allows us to study the impact of employing service differentiation (prioritization) during admission control and rate control on the classwise blocking probabilities and throughputs. The admission control takes into account the interference from adjacent cells as a log‐normally distributed random variable and employs service class and state‐dependent (soft) blocking in addition to hard blocking. The state‐dependent rate control algorithm takes into account the minimum and maximum requested rates of admitted sessions in a fairness policy‐dependent manner. Our conclusion is that work conserving bandwidth sharing policies may have a major impact on the moments of the time spent in the system by elastic services, but only a minor one on the classwise blocking probabilities. When the admission control algorithm takes into account the neighbour cell caused interference, the blocking probability of all classes increases somewhat, but the throughput of the accepted sessions increases. Blocking prioritization in the soft blocking model affects the classwise total blocking probabilities but has little impact on the throughput of adaptive and elastic traffic. Copyright © 2006 John Wiley & Sons, Ltd.
Bit error rate evaluation of linear equalization in FWA systems
Authors: Xiao Pei , Carrasco Rolando , Wassell Ian
Published: May 2006

The bit error rate performance of broadband wireless fixed access (FWA) systems over multipath fading channels is investigated in this paper. Linear MMSE equalization is examined theoretically for 16‐QAM and QPSK modulated FWA systems and shown to yield unsatisfactory performance. The theoretical analysis is validated by Monte‐Carlo simulations and proved to be reasonably accurate. It provides us an insight into the physical limitations imposed by the FWA channels and suggest solutions to improve the capacity and performance of future FWA systems. Copyright © 2006 John Wiley & Sons, Ltd.
Association of peripheral total and differential leukocyte counts with metabolic syndrome and risk of ischemic cardiovascular diseases in patients with type 2 diabetes mellitus
Authors: Tsai Jack C.‐R. , Sheu Sheng‐Hsiung , Chiu Herng‐Chia , Chung Fu‐Mei , Chang Dao‐Ming , Chen Miao‐Pei , Shin Shyi‐Jang , Lee Yau‐Jiunn
Published: May 2006

Background

There is increasing evidence that leukocytes play a central role in obesity, glucose intolerance, type 2 diabetes mellitus (T2DM), and cardiovascular diseases, but the role of differential leukocytes in metabolic syndrome (MetS) and atherosclerosis is largely unknown. The aim of this study was to examine the relationship between the component features of MetS and peripheral leukocyte counts and to explore whether leukocyte counts are associated with clustering of MetS and macrovascular diseases in patients with T2DM.

Methods

1872 subjects with T2DM who enrolled in a diabetes disease management program were studied. The definition of MetS was modified from that outlined by the criteria of NCEP‐ATP III. Areas under the receiver‐operating characteristic curve and odds ratios at various intervals of the WBC counts were computed.

Results

The peripheral total leukocyte, monocyte, and neutrophil cell counts are increased parallel to the clustering of components of MetS. When white cell counts were analyzed per quartile and as continuous variables after adjustment for age, sex, and other known risk factors with multiple regression analysis, peripheral total leukocyte, monocyte, neutrophils, and lymphocyte counts were independently and significantly associated with specific features of clustering of MetS and prevalence of ischemic cardiovascular diseases. Leukocyte counts, especially neutrophil/lymphocyte ratio, in addition with MetS is associated with the risk of ischemic cardiovascular diseases.

Conclusion

Our results indicate that differential leukocyte counts are associated with MetS and that peripheral leukocytes may play a role in the pathogenesis of macrovascular complications in patients with T2DM. Copyright © 2006 John Wiley & Sons, Ltd.
Effects of hypoxia reoxygenation in brain slices from rats with type 1‐like diabetes mellitus
Authors: González‐Correa J. A. , Arrebola M. M. , Cansino A. L. , Muñoz‐Marín J. , Ruiz‐Villafranca D. , Guerrero A. , Sánchez de la Cuesta F. , De La Cruz J. P.
Published: May 2006

Background

The aim of this study was to determine whether the brain tissue of type 1 diabetic animals is more susceptible to damage by hypoxia reoxygenation than healthy animals.

Methods

This study used rats with diabetes of 1, 2 and 3 months (N= 15 rats/group). Brain slices were subjected to hypoxia and reoxygenation for 180 minin vitro. We measured oxidative stress (lipid peroxidation, glutathione concentration and enzyme activities related to glutathione), concentration of prostaglandin E2(PGE2) and nitric oxide (NO) pathway (nitrite + nitrate, activities of constitutive (cNOS) and inducible (iNOS) nitric oxide synthase). As a parameter of cell death we measured the efflux of lactate dehydrogenase (LDH).

Results

After reoxygenation LDH activity increased in comparison to nondiabetic animals by 40, 40.6 and 68.9% in animals with diabetes of 1, 2 and 3 months duration, respectively. These changes were accompanied by greater increases in lipid peroxides (25.4, 93.7 and 92.8%). PGE2accumulated in significantly larger amounts in diabetic animals (62.5, 85.5 and 114%), and nitrite + nitrate accumulation was significantly greater in rats with diabetes of 2 (40.2%) and 3 months duration (24.0%). iNOS activity increased significantly in all the groups of diabetic animals, with the largest increases in rats with diabetes of 2 (18.6%) and 3 months duration (21.1%).

Conclusions

The biochemical pathways involved in oxidative stress and neuronal death are more sensitive to hypoxia reoxygenation in type 1‐like diabetic, as compared to normal, rats. Copyright © 2006 John Wiley & Sons, Ltd.
Electrocatalytic Determination of Ascorbic Acid at the Surface of 2,7‐Bis(ferrocenyl ethyl)fluoren‐9‐one Modified Carbon Paste Electrode
Authors: Raoof J. B. , Ojani R. , Beitollahi Hadi , Hossienzadeh R.
Published: May 2006

A chemically modified carbon paste electrode with 2,7‐bis(ferrocenyl ethyl)fluoren‐9‐one (2,7‐BFEFMCPE) was employed to study the electrocatalytic oxidation of ascorbic acid in aqueous solution using cyclic voltammetry, differential pulse voltammetry and chronoamperometry. The diffusion coefficient (D=1.89×10−5 cm2 s−1), and the kinetic parameter such as the electron transfer coefficient, α (=0.42) of ascorbic acid oxidation at the surface of 2,7‐BFEFMCPE was determined using electrochemical approaches. It has been found that under an optimum condition (pH 7.00), the oxidation of ascorbic acid at the surface of such an electrode occurs at a potential about 300 mV less positive than that of an unmodified carbon paste electrode. The catalytic oxidation peak currents show a linear dependence on the ascorbic acid concentration and linear analytical curves were obtained in the ranges of 8.0×10−5 M–2.0×10−3 M and 3.1×10−5 M–3.3×10−3 M of ascorbic acid with correlation coefficients of 0.9980 and 0.9976 in cyclic voltammetry and differential pulse voltammetry, respectively. The detection limits (2δ) were determined to be 2.9×10−5 M and 9.0×10−6 M with cyclic voltammetry and differential pulse voltammetry, respectively. This method was also examined for determination of ascorbic acid in pharmaceutical preparations.
Amperometric Biosensor for Lactate Based on Meldola's Blue Adsorbed on Silica Gel Modified with Niobium Oxide
Authors: Pereira Arnaldo C. , Macedo Denise V. , Santos Antonio S. , Kubota Lauro T.
Published: May 2006

A reagentless amperometric biosensor sensitive to lactate was developed. This sensor comprises a carbon paste electrode modified with lactate dehydrogenase (LDH), nicotinamide adenine dinucleotide (NAD+) cofactor and Meldola's blue (MB) adsorbed on silica gel coated with niobium oxide. The amperometric response was based on the electrocatalytic properties of MB to oxidize NADH, which was generated in the enzymatic reaction of lactate with NAD+ under catalysis of LDH. The dependence on the biosensor response was investigated in terms of pH, supporting electrolyte, ionic strength, LDH and NAD+ amounts and applied potential. The biosensor showed an excellent operational stability (95% of the activity was maintained after 250 determinations) and storage stability (allowing measurements for over than 2.5 months, when stored in a refrigerator). The proposed biosensor also presented good sensitivity allowing lactate quantification at levels down to 6.5×10−6 mol L−1. Moreover, the biosensor showed a wide linear response range (from 0.1 to 14 mmol L−1 for lactate). These favorable characteristics allowed its application for direct measurements of lactate in biological samples such as blood. The precision of the data obtained by the proposed biosensor show reliable results for real complex matrices.
Assessment of seismic design procedures based on the total cost
Authors: Lagaros Nikos D. , Fotis Andreas D. , Krikos Stilianos A.
Published: May 2006

The assessment of seismic design codes has become the subject of intensive research work which revealed several weak points of the codes that originated from the limitations in predicting with acceptable precision the response of a structure under a moderate or severe earthquake. Most of the seismic design codes belong to the class of prescriptive procedures, where if certain constraints are fulfilled, the structure is considered safe. Prescriptive design procedures fail to provide acceptable levels of structural performance over its life because, in most of them, the structure is assessed using only one design earthquake. Performance‐based design is a different philosophy for designing against hazards; the structure is designed to meet a number of performance objectives. The objectives of this study is to compare the initial and limit state‐dependent cost of an RC building designed either to meet the provisions of the Greek national seismic design code or based on a performance‐based design procedure. Two were the most important findings of this study: (i) the initial cost for an RC structure, designed to permit elastic behaviour for the response spectrum of the Greek national seismic code, is not prohibitive and (ii) that an RC structure based on the proposed performance‐based design procedure lead to economical designs with respect to the total cost compared to a code conforming design. Copyright © 2006 John Wiley & Sons, Ltd.
Solidification in a water‐saturated porous medium when convection is present (response of solid‐liquid interface due to time‐varying cooling temperature)
Authors: Kimura Shigeo , Okajima Atsushi , Kiwata Takahiro , Fusaoka Takahiro
Published: May 2006

A fundamental study on solidifying phenomenon in a rectangular space filled with water‐saturated porous medium has been carried out with a system, cooled from the upper boundary and heated from below, where vigorous convection develops in the un‐solidified liquid layer. The dynamic response of the solid‐liquid interface to the periodical cooling temperature with the bottom boundary kept at constant temperature TH = 20°C, is investigated experimentally. In particular, the amplitude of the interface and the phase lag in respect to the oscillating cooling temperature have been monitored for various periods and average temperatures. A one‐dimensional numerical model, based on an assumption of constant heat flux from the vigorously convecting liquid regime has been also developed. The numerical model predicts quite well the time‐dependent behavior of the horizontally averaged ice‐layer thickness observed in the experiments. Our general findings are that the amplitude increases proportionally to the temperature fluctuation period and that both the thicker solid layer and the shorter period cause greater phase lags. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(4): 294–308, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20109
DNS of turbulent heat transfer in a channel flow with a varying streamwise thermal boundary condition
Authors: Seki Yohji , Kawamura Hiroshi
Published: May 2006

Direct numerical simulation (DNS) was performed for the turbulent heat transfer in a channel flow. In the present study, the effect of the thermal boundary condition was examined. DNS was carried out for varying streamwise thermal boundary conditions (Reτ = 180) with Pr = 0.71 to obtain statistical mean temperatures, temperature variances, budget terms, and time scale ratios. The results obtained indicate that the time scale ratio varies along the stream direction. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(4): 265–278, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20114
Molecular dynamics of the generation process of double‐walled carbon nanotubes from peapods
Authors: Shibuta Yasushi , Maruyama Shigeo
Published: May 2006

The generation process of a double‐walled carbon nanotube (DWNT) from a “peapod” was studied by classical molecular dynamics simulation. Starting from a peapod structure, defined by five C60 molecules inside a (10,10) single‐walled carbon nanotube (SWNT), polymerized fullerenes, a peanut‐like structure and an almost nanotube‐like structure were obtained under suitable conditions of temperature control. The mean distance between the two layers of the DWNT agreed with an experimental report that it is larger than the interlayer spacing found in multi‐walled carbon nanotubes (MWNTs). In addition, the chirality dependence of the potential energy of a DWNT on the relative chirality of its constituent tubes was examined using a 6‐12 Lennard‐Jones potential. It was found that the potential energy depends only on the distance between the two layers, not on the relative chiralities. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(4): 254–264, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20115
A study on thermal conductivity of a mixture of magnesia particles and molten nitrate by a transient hot wire method
Authors: Kitano Kazuyuki , Hanyuda Katsuya , Takegoshi Eisyun , Sawada Masatoshi , Hirasawa Yoshio , Kosaka Akio
Published: May 2006

In this study, the effective thermal conductivity of a mixture of magnesia particles and molten nitrate used in a high temperature thermal energy storage system was investigated by a transient hot wire method. The effective thermal conductivity of the mixture was around 2.0W/(m·K) in the temperature range of 423 K to 703 K, although it decreased about 5% with increasing temperature. This value was about 10 times larger than that of the packed bed of magnesia particles including air. The effective thermal conductivity increased about 3% with a 1% increase in the volume ratio of magnesia particles in the mixture with molten nitrate. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(4): 245–253, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20116
The composite method: an improved method for stream‐water solute load estimation
Authors: Aulenbach Brent T. , Hooper Richard P.
Published: May 2006

The composite method is an alternative method for estimating stream‐water solute loads, combining aspects of two commonly used methods: the regression‐model method (which is used by the composite method to predict variations in concentrations between collected samples) and a period‐weighted approach (which is used by the composite method to apply the residual concentrations from the regression model over time). The extensive dataset collected at the outlet of the Panola Mountain Research Watershed (PMRW) near Atlanta, Georgia, USA, was used in data analyses for illustrative purposes. A bootstrap (subsampling) experiment (using the composite method and the PMRW dataset along with various fixed‐interval and large storm sampling schemes) obtained load estimates for the 8‐year study period with a magnitude of the bias of less than 1%, even for estimates that included the fewest number of samples. Precisions were always <2% on a study period and annual basis, and <2% precisions were obtained for quarterly and monthly time intervals for estimates that had better sampling. The bias and precision of composite‐method load estimates varies depending on the variability in the regression‐model residuals, how residuals systematically deviated from the regression model over time, sampling design, and the time interval of the load estimate. The regression‐model method did not estimate loads precisely during shorter time intervals, from annually to monthly, because the model could not explain short‐term patterns in the observed concentrations. Load estimates using the period‐weighted approach typically are biased as a result of sampling distribution and are accurate only with extensive sampling. The formulation of the composite method facilitates exploration of patterns (trends) contained in the unmodelled portion of the load. Copyright © 2006 John Wiley & Sons, Ltd.
Runoff and suspended sediment yields from an unpaved road segment, St John, US Virgin Islands
Authors: Ramos‐Scharrón Carlos E. , MacDonald Lee H.
Published: May 2006

Unpaved roads are believed to be the primary source of terrigenous sediments being delivered to marine ecosystems around the island of St John in the eastern Caribbean. The objectives of this study were to: (1) measure runoff and suspended sediment yields from a road segment; (2) develop and test two event‐based runoff and sediment prediction models; and (3) compare the predicted sediment yields against measured values from an empirical road erosion model and from a sediment trap. The runoff models use the Green–Ampt infiltration equation to predict excess precipitation and then use either an empirically derived unit hydrograph or a kinematic wave to generate runoff hydrographs.

Precipitation, runoff, and suspended sediment data were collected from a 230 m long, mostly unpaved road segment over an 8‐month period. Only 3–5 mm of rainfall was sufficient to initiate runoff from the road surface. Both models simulated similar hydrographs. Model performance was poor for storms with less than 1 cm of rainfall, but improved for larger events. The largest source of error was the inability to predict initial infiltration rates.

The two runoff models were coupled with empirical sediment rating curves, and the predicted sediment yields were approximately 0·11 kg per square meter of road surface per centimetre of precipitation. The sediment trap data indicated a road erosion rate of 0·27 kg m−2cm−1. The difference in sediment production between these two methods can be attributed to the fact that the suspended sediment samples were predominantly sand and silt, whereas the sediment trap yielded mostly sand and gravel. The combination of these data sets yields a road surface erosion rate of 0·31 kg m−2cm−1, or approximately 36 kg m−2year−1. This is four orders of magnitude higher than the measured erosion rate from undisturbed hillslopes. The results confirm the importance of unpaved roads in altering runoff and erosion rates in a tropical setting, provide insights into the controlling processes, and provide guidance for predicting runoff and sediment yields at the road‐segment scale. Copyright © 2006 John Wiley & Sons, Ltd.
Influence of various cell‐detachment solutions on endothelial cells after catheter abrasion for prosthesis colonization prior to implantation
Authors: Priebe Markus , Müller‐Hülsbeck Stefan , Jahnke Thomas , Charalambous Nikolas , Hedderich Jürgen , Heller Martin , Paulsen Friedrich Paul
Published: May 2006

We (1) evaluated the effectiveness of different media on the detachment of endothelial cells (ECs) from a catheter brush (Cragg thrombolytic catheter system) that was previously used for endothelial cell abrasion in 10 cm human umbilical vein (HUV) segments; (2) tested the practicability of endovascular catheter brush abrasion followed by EC detachment from the catheter brush, in vitro culture of harvested ECs, and finally endothelialization of a prosthesis; and (3) analyzed the defect created by the catheter brush in HUV segments after endovascular catheter abrasion. Best results in detachment of ECs from the catheter brush were obtained with a mixture of phosphate‐buffered saline + 1% human albumin. EC vitality was time‐dependent in the collected HUV segments postdelivery. Harvested EC viability decreased from (26.28 ± 5.76)% (0–3 h postdelivery) to (17.29 ± 4.56)% (after 4–8 h). ECs were easily cultured ex vivo within 2–3 weeks; seeded on nitinol stents, they grew to confluency and formed a monolayer on the stent surface (determined by scanning electron microscopy – SEM). Histological and SEM analysis of HUV segments that had undergone previous catheter brush abrasion revealed slight disruption of the intima but intact subintimal layers. Our findings indicate an advantageous method of capturing and culturing primary ECs for gene therapy or for the analysis and diagnosis of certain blood vessel diseases, especially in cases in which endovascular intervention is performed anyway. Moreover, and of high relevance to the biomaterial field, theoretically the procedure could be used to endothelialze a prosthesis ex vivo for implantation into the patient from whom the ECs were harvested, to reduce the inherent thrombogenicity of the prosthesis. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Upregulation of secretory connective tissue growth factor (CTGF) in keratinocyte‐fibroblast coculture contributes to keloid pathogenesis
Authors: Khoo Ying Ting , Ong Chee Tian , Mukhopadhyay Anandaroop , Han Hwan Chour , Do Dang Vinh , Lim Ivor Jiun , Phan Toan Thang
Published: May 2006

Connective tissue growth factor (CTGF) plays a critical role in keloid pathogenesis by promoting collagen synthesis and deposition. Previous work suggested epithelial‐mesenchymal interactions as a plausible factor affecting the expression of various growth factors and cytokines by both the epithelial and dermal mesenchymal cells. The aim of this study is to explore the role of epithelial‐mesenchymal interactions in modulating CTGF expression. Immunohistochemistry was employed to check CTGF localization in skin tissue. Western blot assay was performed on total protein extracts from skin tissue, cell lysates and conditioned media to detect the basal/expression levels of CTGF. Study groups were subjected to serum stimulation (fibroblast‐single cell culture) and pharmacological inhibitors targeted against mTOR (Rapamycin), Sp1 (WP631 and Mitoxanthrone), Smad3 (SB431542), and PI3K (LY294002). Increased localization of CTGF in the basal layer of keloid epidermis and higher expression of CTGF was observed in the keloid tissue extract. Interestingly, lower basal levels of CTGF was observed in fibroblast cell lysates cocultured with keloid keratinocytes compared to normal keratinocytes, while the conditioned media from the former culture consistently demonstrated a higher expression of secreted CTGF as compared to the latter group. These results demonstrate an important role of epithelial‐mesenchymal interactions in the regulation of CTGF expression. Fibroblasts treated with inhibitors against mTOR, Sp1, Smad3, and PI3K demonstrated a reduced expression of CTGF, suggesting these signaling pathways to be important in the regulation of CTGF expression. Thus, revealing the therapeutic potentials for inhibitors that are selective for these factors in controlling CTGF expression in fibrotic conditions. J. Cell. Physiol. 208: 336–343, 2006. © 2006 Wiley‐Liss, Inc.
Atmospheric pressure photoionization‐mass spectrometry and atmospheric pressure chemical ionization‐mass spectrometry of neurotransmitters
Authors: Kauppila T. J. , Nikkola T. , Ketola R. A. , Kostiainen R.
Published: May 2006

A group of five neurotransmitters with different properties was analyzed using atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization‐mass spectrometry (APCI‐MS). The sensitivity of the techniques for the analytes was tested in six solvents and in positive and negative ion modes. APPI was found to be superior in sensitivity for all the compounds in both positive and negative ion modes. In positive ion mode, water/methanol/formic acid was found to be the best solvent, whereas in negative ion mode, water/methanol/ammonium hydroxide performed best. Detection limits using APPI were between 2.5–250 fmol, depending on the compound. The sensitivity was best for the neurosteroids dehydroepiandrosterone and β‐estradiol, and acetylcholine (LOD 2.5–10 fmol). Copyright © 2006 John Wiley & Sons, Ltd.
Gas chromatography and mass spectrometry of methoxylated polybrominated diphenyl ethers (MeO‐PBDEs)
Authors: Athanasiadou Maria , Marsh Göran , Athanassiadis Ioannis , Asplund Lillemor , Bergman Åke
Published: May 2006

Twenty‐six methoxylated polybrominated diphenyl ethers (MeO‐PBDEs) were characterized by gas chromatography (GC) on four different GC columns with different lengths and polarities, as well as by mass spectrometry using three ionization techniques, electron ionization (EI), electron capture negative ionization (ECNI) and positive ion chemical ionization (PICI). MeO‐PBDE congeners with similar retention times on a nonpolar GC column were separated when analyzed on a polar GC column. EI can be used to determine the position of the methoxy substituent (ortho, meta or para) relative to the diphenyl ether oxygen in the MeO‐PBDEs. The PICI ionization technique is shown to be valuable to generate structural information of the MeO‐PBDEs, i.e. the degree of bromination on both the methoxy‐substituted ring and the entirely brominated phenyl ring can be obtained. This structure information can also be achieved for certain MeO‐PBDEs with the methoxy group in ortho position to the diphenyl ether bond in ECNI mode. Like other brominated compounds ECNI is preferable when analyzing environmental samples for quantification of MeO‐PBDEs because of the formation of bromide ions, which enables low detection limits. Copyright © 2006 John Wiley & Sons, Ltd.
Climatic behavior of various urban parks during hot and humid summer in the mediterranean city of Tel Aviv, Israel
Authors: Potchter Oded , Cohen Pninit , Bitan Arieh
Published: May 2006

This study examines the climatic behavior of different designs of urban parks during hot and humid summer conditions, and their influence on human comfort in Tel Aviv, Israel. The research was conducted in three different types of urban parks: a park with grass and a few low trees, a park with medium sized trees and a park with high and wide‐canopied trees. The results showed that an urban park that contains high trees with a wide canopy has the maximum cooling effect during daytime, reduces temperatures by up to 3.5 °C and lowers heat stress values despite increasing relative humidity values. An urban park that contains dense, medium sized trees can also reduce temperatures during daytime by up to 2.5 °C as well as slightly lower heat stress. However, during nighttime it can create uncomfortable climatic conditions owing to the reduction of wind velocity and increase in relative humidity. An urban park covered with grass can be warmer and sometimes even more humid than the built‐up area during the day, which increases heat stress values. Copyright © 2006 Royal Meteorological Society.
Changes in perlecan during chondrocyte differentiation in the fetal bovine rib growth plate
Authors: West Leigh , Govindraj Prasanthi , Koob Thomas J. , Hassell John R.
Published: May 2006

Perlecan is a heparan sulfate proteoglycan present in the growth plate and essential for endochondral ossification. We evaluated the synthesis and structure of perlecan in the different zones of the growth plate. The growth plates from fetal bovine ribs were isolated and sequentially sliced into 1‐mm sections containing the hypertrophic zone, lower proliferative zone, upper proliferative zone, intermediate zone, and resting zone, respectively. The slices were then either incubated in culture medium with 35SO4 to measure total sulfated proteoglycan synthesis and perlecan synthesis, extracted for perlecan core protein analysis by Western blot, or extracted for perlecan isolation and subsequent characterization of glycosaminoglycan size and disaccharide composition. 35SO4 incorporation into perlecan was three–fourfold higher in the proliferating/hypertrophic zone than the resting zone. Western blot showed perlecan content was greatest in the lower and upper proliferating zones and that a perlecan fragment lacking portions of the N‐ and C‐terminal domains containing heparan sulfate was also present in all zones. Purified perlecan from the hypertrophic/lower proliferative zone had larger chondroitin sulfate chains and a different composition of CS and HS disaccharides than the perlecan isolated from the resting zone. These results indicate perlecan deposition is increased and is turned over during proliferation to be replaced by a perlecan with a different sulfation pattern. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1317–1326, 2006
Variability in tendon and knee joint biomechanics among inbred mouse strains
Authors: Wang Vincent M. , Banack Trevor M. , Tsai Christine W. , Flatow Evan L. , Jepsen Karl J.
Published: May 2006

Hereditary factors are thought to be responsible for impaired tendon function and joint laxity. The present study investigated the genotypic variability of knee laxity and stiffness and tendon mechanical and geometric properties among 16‐week‐old female A/J, C57BL/6J (B6), and C3H/HeJ (C3H) inbred mice. In one group of mice, knee mechanics were quantified using a custom loading apparatus enabling translation of the tibia against a stationary femur. In a second group, flexor digitorum longus and Achilles tendons from the left hind limb underwent biomechanical testing, while those of the contralateral limb were analyzed histologically for determination of cross‐sectional area. Our results demonstrate that tendon and joint mechanics varied significantly among the inbred mouse strains, indicating that biomechanical properties are genetically determined. A/J mouse knees exhibited greater laxity (p < 0.001) and lower stiffness (p < 0.001) compared to those of the B6 and C3H mice. The genotypic differences in whole joint properties were similar to those of the tendons' structural biomechanical traits. Although body mass did not differ (p > 0.2) among the three strains, significant genotypic differences were found at the whole tendon, material quality, and morphological levels of the tissue hierarchy. Furthermore, genetic regulation of tendon mechanical properties varied with anatomic site. Patterns of genotypic differences in tendon size were not consistent with those of biomechanical properties, suggesting that unique combinations of structural and compositional factors contribute to tendon growth, adaptation, and development. Therefore, the three inbred strains constitute a useful experimental model to elucidate genetic control of structure–function relationships in normal and healing tendons and ligaments. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1200–1207, 2006
Prolonged down regulation of specific gene expression in nucleus pulposus cell mediated by RNA interference in vitro
Authors: Kakutani Kenichiro , Nishida Kotaro , Uno Koki , Takada Toru , Shimomura Takatoshi , Maeno Koichiro , Kurosaka Masahiro , Doita Minoru
Published: May 2006

To investigate the efficacies and the longevity of RNA interference in nucleus pulposus cells from rat and human, two reporter luciferase plasmids (Firefly and Renilla) were used. These plasmids were cotransfected with siRNA targeting Firefly luciferase to the nucleus pulposus cells extracted from Sprague Dawley rats and scoliosis patients. The inhibitory effects were evaluated by dual luciferase assay for 3 weeks. Proliferation activity of fibroblast‐like cells extracted from the subcutaneous tissue of Sprague Dawley rats and the nucleus pulposus cells were measured by proliferation assay (WST‐8 assay) every 2 days after plating. The expression of Firefly luciferase was drastically inhibited both in rats (94.7%) and in humans (93.7%). The inhibitory effects were maintained for 2 weeks and had disappeared completely by 3 weeks. The proliferation activity of nucleus pulposus cells was significantly lower than fibroblast‐like cells. We have shown, for the first time, siRNA‐mediated gene silencing in rat and human disc cells for a relatively sustained period, probably due to the stability of the nucleus pulposus cells in terms of cell proliferation. The demonstration of this study may allow further exploration of the use of siRNA for scientific research and the treatment of disc degenerative diseases. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1271–1278, 2006
Apoptosis induced by chemotherapeutic agents involves c‐Jun N‐terminal kinase activation in sarcoma cell lines
Authors: Koyama Takaaki , Mikami Takashi , Koyama Takashi , Imakiire Atsuhiro , Yamamoto Kengo , Toyota Hiroko , Mizuguchi Junichiro
Published: May 2006

Molecular mechanisms underlying chemotherapeutic agent–induced apoptosis in sarcoma cells are not well known. Induction of apoptosis is regulated by several components including mitogen‐activated protein kinases (MAPKs) comprising ERK, p38MAPKs, and c‐Jun N‐terminal kinase (JNK). In the present study, we examined whether activation of JNK is induced by the chemotherapeutic agents cis‐diaminedichloroplatinum (cisplatin, CDDP) or doxorubicin (DXR), and whether the ectopic expression of constitutively active (MKK7‐JNK1) or dominant‐negative form of JNK (dnJNK) influenced apoptosis in response to the CDDP or DXR in sarcoma cell lines MG‐63 and SaOS‐2. The CDDP or DXR induced JNK activation in the both cell lines, as assessed by Western blotting using phosphospecific antibodies. A transient expression of the activated form of JNK sensitized the MG‐63 and SaOS‐2 cells to the drug‐induced apoptosis, while dnJNK1 reduced the proportion of apoptotic cell death. Apoptosis was determined by flow cytometry using annexin‐V Cy5. Collectively, our results indicate that JNK activation is involved in apoptotic cell death in sarcoma cell lines following stimulation with CDDP or DXR. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1153–1162, 2006
Inhibitory effects of a new bisphosphonate, minodronate, on proliferation and invasion of a variety of malignant bone tumor cells
Authors: Kubo Tadahiko , Shimose Shoji , Matsuo Toshihiro , Tanaka Kumi , Yasunaga Yuji , Sakai Akira , Ochi Mitsuo
Published: May 2006

Little is known about the biological effects of bisphosphonates on primary malignant bone tumors. The purpose of this study was to investigate the antitumor effects of newly developed minodronate (MIN) on a variety of human malignant bone tumors. We examined the effects of MIN and clinically relevant incadronate (INC) on the proliferation, apoptosis, and cell cycle of two osteosarcoma (Saos‐2, MG‐63), two chondrosarcoma (SW1353, OUMS27), and two Ewing's sarcoma (RD‐ES, SK‐ES‐1) cell lines. Furthermore, we investigated the anti‐invasion effects of MIN on sarcoma cells and the effects of MIN on tumor growth in nude mice. MIN inhibited the viability of all six cell lines in a dose‐dependent manner with IC50 values of 2.7 to 5.0 µM, which were significantly lower than those of INC. Importantly, both bisphosphonates affected the viability of normal bone marrow stromal cells much less than sarcoma cells. Both bisphosphonates induced cell cycle perturbation in all sarcoma cells tested and apoptosis in Saos‐2 and SW1353 cells, although they failed to induce apoptosis in RD‐ES and SK‐ES‐1 cells. MIN significantly suppressed invasion, even at a low concentration of 1 µM (p < 0.01). Daily injection of 5 µg of MIN inhibited the growth of SK‐ES‐1 xenograft sarcoma in nude mice without loss of body weight. These findings suggest that MIN may have a beneficial adjuvant role in the treatment of patients with malignant bone tumors. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1138–1144, 2006
Release of nitric oxide, but not prostaglandin E2, by bone cells depends on fluid flow frequency
Authors: Mullender Margriet G. , Dijcks Saskia J. , Bacabac Rommel G. , Semeins Cornelis M. , Van Loon Jack J.W.A. , Klein‐Nulend Jenneke
Published: May 2006

Loading frequency is an important parameter for the stimulation of bone formation in vivo. It is still unclear how the information of external loading characteristics is conveyed to osteoblasts and osteoclasts. Osteocytes are thought to detect mechanical loads by sensing fluid flow through the lacuno‐canalicular network within bone and to translate this information into chemical signals. The signaling molecules nitric oxide (NO) and prostaglandin E2 (PGE2) are known to play important roles in the adaptive response of bone to mechanical loads. We have investigated the effects of fluid flow frequency on the production of PGE2 and NO in bone cells in vitro. Pulsatile fluid flow with different frequencies stimulated the release of NO by MC3T3‐E1 osteoblasts in a dose‐dependent manner. In contrast, PGE2 production was enhanced consistently by all fluid flow regimes, independent of flow frequency. This implies that the NO response may play a role in mediating the differential effects of the various loading patterns on bone. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1170–1177, 2006
The use of Raman spectrometry to predict the stability of historic glasses
Authors: Robinet Laurianne , Coupry Claude , Eremin Katherine , Hall Christopher
Published: May 2006

In the National Museums of Scotland (NMS) widespread alterations have been observed in the glass collections of 19th to 20th century, affecting British, Islamic and Asian glasses. It is important for museums to be able to distinguish between stable and unstable glasses, so that particular care can be taken to preserve the most sensitive objects. Elemental analysis by electron microprobe of a selection of stable and unstable British and Islamic glasses indicated that the composition was directly linked to the degree of stability of the glass. Because sampling of glass objects is often difficult or impossible, we investigated the ability of Raman spectroscopy, which can be applied in situ and non‐destructively, to distinguish between stable and unstable glasses. The analysis concentrated on the soda‐lime silicate glasses, which displayed a mixed stability. We show, by combining the elemental composition and the Raman spectroscopy data, that a correlation can be established between the 550 cm−1 band shift and the SiO2 content (or degree of polymerisation). A second correlation was established between the 950 cm−1 band and the number of cations charge‐coordinated to the silicate with two non‐bridging oxygens (NBOs). Finally, a method based on the peak area ratio (A900 + A950 + A990)/(A900–1150) from the Raman spectrum is proposed to determine the stability of soda silicate glass. Copyright © 2006 John Wiley & Sons, Ltd.
Preoperative chemoradiation in rectal cancer: Retrospective comparison between capecitabine and continuous infusion of 5‐fluorouracil
Authors: Yerushalmi Rinat , Idelevich Efraim , Dror Ygael , Stemmer Salomon M. , Figer Arie , Sulkes Aaron , Brenner Baruch , Loven David , Dreznik Zeev , Nudelman Israel , Shani Adi , Fenig Eyal
Published: May 2006

Background

We compared the efficacy and toxicity of oral capecitabine and continuous infusion of 5‐fluorouracil (5‐FU) in the preoperative chemoradiation treatment of patients with rectal cancer.

Patients and Methods

The files of 89 patients with rectal cancer, 43 treated preoperatively with oral capecitabine and 46 with intravenous 5‐FU, were reviewed, and the outcome of the groups was compared.

Results

There was no statistically significant difference in the complete pathological response rate between the capecitabine and the 5‐FU groups (30% vs. 17%, P = 0.15). The downstaging rate was higher in the capecitabine group (77% vs. 50%, P = 0.009). Toxicity was mild in both groups. The rate of Grade 3 gastrointestinal toxicity was similar in the two groups (diarrhea 2% vs. 4%, proctitis 5% vs. 7%), except for one patient in the 5‐FU group (2%) who developed a rectovaginal fistula. In the capecitabine group, one patient (2%) had Grade 3 hand‐foot syndrome, and another had an acute myocardial infarction. In the 5‐FU group, two patients (4%) had Grade 3 hematological toxicity, and three (6%) had complications from Port‐a‐Cath insertion.

Conclusion

Preoperative chemoradiation with oral capecitabine appears to be safe and well tolerated, and at least as good as continuous 5‐FU. J. Surg. Oncol. 2006;93:529–533. © 2006 Wiley‐Liss, Inc.
Outcomes of resection of stage IV rectal cancer with mesorectal excision
Authors: Law Wai Lun , Chu Kin Wah
Published: May 2006

Background

There is no consensus as to the management of the primary rectal cancer in the presence of distant metastasis and data on the outcomes of radical resection in stage IV rectal cancer are limited. This study aims to evaluate the results of resection of rectal cancer in the patients with stage IV disease and to analyze the factors that might affect the survival of these patients.

Methods

Of the 744 patients with radical resection of primary rectal and rectosigmoid cancer during the study period from August 1993 to July 2002, 70 had stage IV disease on the initial presentation. The demographics, the operative details, the tumor characteristics, the postoperative outcomes and survival of the patients were collected prospectively. Factors influencing the survival were analyzed with univariate and multivariate analysis.

Results

Fifty‐three men and 17 women with a median age of 66 years (range: 31–90 years) were included. The median level of the tumor from the anal verge was 10 cm (range 3–20 cm). The operations included abdominoperineal resection (n = 5), anterior resection (n = 53), and Hartmanns operation (n = 11). The operation mortality was 4.3%. The overall morbidity was 42.7% while the surgical morbidity and the reoperation rates were 15.7% and 5%, respectively. The local recurrence rate was 4.3% and the 2‐year actuarial rate was 7.8%. All the patients who had local recurrences also had disseminated peritoneal metastasis. The median cancer‐specific survival of the patients who survived the surgery was 15.2 months. Multivariate analysis showed that the presence of gross residual local disease, lymph node metastasis, liver involvement of over 50%, the absence of surgical management of liver metastasis and those without chemotherapy were independent factors associated with poor survival.

Conclusions

Postoperative mortality and morbidity were acceptable in patients with stage IV rectal cancer. The local disease can be controlled effectively with radical resection. However, in patients with extensive liver involvement and advanced local disease, resection is not worthwhile because of the poor survival. Surgical management of the metastasis and the administration of chemotherapy are associated with better survival. However, the optional treatment regimes are yet to be defined. J. Surg. Oncol. 2006;93:523–528. © 2006 Wiley‐Liss, Inc.
Quality of life in newly diagnosed cancer patients waiting for surgery is seriously impaired
Authors: Visser Mechteld R.M. , van Lanschot J. Jan B. , van der Velden Jacobus , Kloek Jaap J. , Gouma Dirk J. , Sprangers Mirjam A.G.
Published: May 2006

Background and Objectives

Newly diagnosed cancer patients waiting for initial surgery experience a stressful time. Study objectives were (1) to examine the quality of life (QL) of these patients by comparing QL (a) between the four diagnostic groups included in this study, (b) to the QL of the general population, (2) to determine the factors that contribute most to patients' overall QL.

Methods

One hundred ninety six patients with lung, periampullary, oesophageal and cervical cancer completed questionnaires on generic QL (SF‐36), overall QL, cancer‐site specific symptoms (EORTC‐modules), anxiety (STAI), health expectations, demographics and comorbidity.

Results

Between diagnostic groups no significant differences were found on generic QL. As compared to the general population, generic QL was impaired on all aspects except bodily pain. Using stepwise regression analysis, 46% of the variance in overall QL was explained with the SF‐36 scales vitality (Beta = 0.43) and mental health (Beta = 0.23) being the most important predictors.

Conclusions

The QL of these patients is seriously impaired. In this stage, not cancer‐site specific aspects but fatigue and emotions colour their lives. It is recommended to keep the waiting period brief. In addition, suggestions are offered by which physicians might help their patients in alleviating the distress. J. Surg. Oncol. 2006;93:571–577. © 2006 Wiley‐Liss, Inc.