bluuebunny/crossref_metadata_2025 huggingface dataset:
The frequency of ipsilateral second tumors after breast‐conserving surgery for DCIS
Authors: Warren Joan L. , Weaver Donald L. , Bocklage Therese , Key Charles R. , Platz Charles E. , Cronin Kathleen A. , Ballard‐Barbash Rachel , Willey Shawna C. , Harlan Linda C.
Published: September 2005

BACKGROUND

The diagnosis of ductal carcinoma in situ (DCIS) is increasing, although to the authors' knowledge there is no consensus regarding optimal treatment. This analysis of women treated with breast‐conserving surgery (BCS) evaluated the impact of radiation therapy (RT) in patient outcomes.

METHODS

The current study included a population‐based sample of 1103 women residing in selected Surveillance, Epidemiology, and End Results (SEER) registries who were diagnosed with DCIS between 1991–1992. Data were obtained from the registry, physician follow‐up, and pathology reports. Physicians were contacted in 1999 to determine whether the patient had developed a second event in the ipsilateral breast. For second events, pathology reports were reviewed to determine the presence of in situ or invasive disease. Registry data through 2001 were used to assess death rates and cause of death. Cox proportional hazards and logistic regression models were used to evaluate the rates of second events and breast carcinoma deaths between women treated with and without RT.

RESULTS

Over an average of 91 months, 13.2% of women developed a second event. Rates of second events were 11% for women treated with BCS and RT compared with 15% for women treated with BCS only (adjusted hazards ratio, 0.64; 95% confidence interval, 0.44–0.92). Women receiving RT were significantly less likely to develop invasive breast carcinoma in the ipsilateral breast (adjusted odds ratio, 0.40). By 2001, the rate of death from breast carcinoma was 2.7%; in the group of women treated with BCS only compared with 0.8% in the group of women treated with BCS with RT.

CONCLUSIONS

Among a population‐based cohort, RT was found to significantly reduce the risk of second events in the ipsilateral breast, particularly invasive tumors, although not to the extent reported in clinical trials. Cancer 2005. © 2005 American Cancer Society.
Hydromagnetic flow and heat transfer of a conducting Casson fluid in a rectangular channel
Authors: Attia Hazem Ali , Sayed‐Ahmed Mohamed Eissa
Published: September 2005

The transient hydromagnetic flow of an electrically conducting viscous incompressible non‐Newtonian Casson fluid bounded by two parallel non‐conducting plates is studied with heat transfer considering the Hall effect. An external uniform magnetic field is applied perpendicular to the plates and the fluid motion is subjected to a pressure gradient in the axial direction. The lower plate is stationary and the upper plate is suddenly set into motion and simultaneously suddenly isothermally heated to a temperature other than the lower plate temperature. Numerical solutions are obtained for the governing momentum and energy equations taking the Joule and viscous dissipations into consideration. The effect of the Hall term and the parameter describing the non‐Newtonian behaviour on both the velocity and temperature distributions are studied. Copyright © 2005 John Wiley & Sons, Ltd.
Mild Synthesis of β‐Amino‐α,α‐difluoro Ketones from Acylsilanes and Trifluoromethyltrimethylsilane in a One‐Pot Imino Aldol Reaction
Authors: Jonet Sylvain , Cherouvrier Franck , Brigaud Thierry , Portella Charles
Published: September 2005

β‐Amino‐α,α‐difluoro ketones have been very conveniently prepared in a one‐pot procedure from acylsilanes, trifluoromethyltrimethylsilane and imines. The key intermediate in this reaction is a difluoroenoxysilane. The Lewis acid promoted imino aldol reaction was performed with BF3·OEt2 or under very mild conditions using a catalytic amount of Yb(OTf)3. The reaction with chiral benzylimines occurred in good yield with 52–78 % de. Palladium‐catalyzed hydrogenolysis furnished an unprotected β‐amino‐α,α‐difluoro ketone or a β‐amino‐α,α‐difluoro alcohol. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis and Solubility Properties of Methanofullerenes Containing Primary Ammonium Ion Functionalities
Authors: Garlaschelli Luigi , Pasini Dario , Spiaggia Federica
Published: September 2005

The synthesis of novel methanofullerene derivatives bearing a primary ammonium ion functionality is described. They are obtained by a Bingel cyclopropanation reaction on C60 with malonate esters, bearing both a solubilizing poly(oxyethylene) chain and an aliphatic chain ending with a BOC‐protected amine. After removal of the protecting group, a counterion exchange methodology allows for the introduction of a perfluorinated anion, bringing the overall solubility of these derivatives to 98 mg/mL in an organic CH2Cl2 solution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
New Unsymmetrical Zinc‐Phthalocyanine Conjugated with One Azo‐Dye Moiety: Synthesis via Opening the Fused Triazole Ring and Spectral Properties
Authors: Àlvarez Micó Xavier , Vagin Sergei I. , Subramanian Lakshminarayanapuram R. , Ziegler Thomas , Hanack Michael
Published: September 2005

A new method for the preparation of compounds containing an azo‐dye moiety via opening the activated triazole ring upon coupling with nucleophiles was successfully applied to a mono‐triazole‐fused phthalocyaninato zinc complex 1. The prepared unsymmetrical zinc‐phthalocyanine 3 conjugated with a 2‐hydroxy‐1‐naphthylazo moiety in the periphery was characterized by means of UV/Vis‐, FTIR‐, 1H and 13C NMR spectroscopy, MALDI‐TOF spectrometry, and elemental analysis, and the data support its structure. The assignment of signals in the 1H and 13C NMR spectra of compound 3 was based on the data from 2‐D CH‐COSY and HC‐HMBC measurements (C–H coupling across one bond and long‐range H–C coupling). The compound exhibits interesting spectroscopic properties, indicating high acidity of the hydroxy group. This phthalocyanine behaves as a strongly solvatochromic compound and can exist in different forms depending on the concentration and nature of solvent. Additionally, photodecomposition of 3 in chloroform and tetrahydrofuran was found to proceed via different pathways. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Controlled Synthesis of α‐Allenic Ester and Spiro Ketone Derivatives from Tailored α‐Substituted Cycloalkanones Through Cascade Reactions: Exploring the Possible Reaction Pathways by Means of Semiempirical MO Calculations
Authors: Mota Antonio J. , Klein Aurélie , Wendling Florence , Dedieu Alain , Miesch Michel
Published: September 2005

Functionalized bicyclic electrophilic allenes and (or) spiro ketones have been obtained through a cascade reaction when acetylenic ω‐keto esters were treated with tetra‐n‐butylammonium fluoride (TBAF). The isolated products can be modulated by using different starting materials (i.e. varying ring size, spacer length) and reaction times. The results indicate that these reactions take place under kinetic control. In line with this, a semiempirical study was carried out in order to determine the preferred reaction pathways and the preferred cis/trans conformation of the bicyclic allenic derivatives. An excellent correlation was found between theoretical and experimental results, and the whole process dramatically depends on the presence of the HF molecule. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Isolation of Plakinamine I: A New Steroidal Alkaloid from the Marine Sponge Corticium sp. and Synthesis of an Analogue Model Compound
Authors: Zampella Angela , D'Orsi Rosa , Sepe Valentina , De Marino Simona , Borbone Nicola , Valentin Alexis , Debitus Cécile , Zollo Franco , Valeria D'Auria Maria
Published: September 2005

A new cytotoxic steroidal alkaloid, plakinamine I, with an unprecedented 3α‐amino‐19‐acetoxy nucleus was isolated from a Corticium sp. sponge. The structure has been elucidated by spectroscopic analysis and secured by the synthesis of the model 19‐acetoxy‐3α‐aminocholestane. The evaluation of the cytotoxic activities of several synthetic derivatives, intermediates of the above synthesis, allowed us to explore the influence of the different functions on the cytotoxicity observed for natural plakinamine I. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Fluoronaphthalene Building Blocks via Arynes: A Solution to the Problem of Positional Selectivity
Authors: Masson Eric , Schlosser Manfred
Published: September 2005

When 3‐fluoro‐ and 3‐chloro‐1,2‐didehydrobenzenes are generated in the presence of 2‐(trimethylsilyl)furan, two regioisomeric cycloadducts are formed in a 1:2 ratio. However, regioselectivity can be installed by fitting one bulky trimethylsilyl group into sterically critical positions of each of the two reaction components. Thus 3‐fluoro‐6‐trimethylsilyl‐1,2‐didehydrobenzene and 2‐(trimethylsilyl)furan give one cycloadduct exclusively. In this way, the Diels–Alder reaction between suitably adorned arynes and similarly designed furans can open an entry to naphthalene derivatives that have unprecedented substituent patterns that qualify them as building blocks for pharmaceutical or agricultural research. The acid‐catalyzed isomerization of model 1,4‐epoxy‐1,4‐dihydronaphthalenes, the aryne/furan cycloadducts, exhibits unexpected effects on rates and regioselectivity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
(α‐L‐Rhamnopyranosyl)methylphosphonic Acids: Experimental Evidence of the Analogy with α‐L‐Rhamnopyranosyl Phosphate
Authors: Ronchi Silvia , Compostella Federica , Lay Luigi , Ronchetti Fiamma , Toma Lucio
Published: September 2005

(α‐L‐Rhamnopyranosyl)methylphosphonic acid and methyl (2‐O‐methyl‐α‐L‐rhamnopyranosyl)methylphosphonate have been synthesized starting from allyl 3,4‐di‐O‐benzyl‐2‐O‐p‐methoxybenzyl‐α‐L‐rhamnopyranoside. The complete NMR spectroscopic characterization of these two compounds and the comparison of the theoretical and experimental vicinal coupling constants indicates a marked preference for the 1C4 conformation for both compounds, in analogy with the natural phosphate. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The Chemistry of Alkylstrontium Halide Analogues, Part 2: Barbier‐Type Dialkylation of Esters with Alkyl Halides
Authors: Miyoshi Norikazu , Matsuo Tsuyoshi , Wada Makoto
Published: September 2005

The chemistry of an alkylstrontium halide analogue was examined. In the presence of metallic strontium, the Barbier‐type alkylation of esters with alkyl iodides proceeded smoothly at room temperature, under argon, to afford the corresponding dialkylated alcohols in good yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Halogenated Oxabicyclo[3.2.1]octadiene Building Blocks: Elaboration of the Dibromoenone
Authors: Pelphrey Phillip M. , Orugunty Ravi S. , Helmich Richard J. , Battiste Merle A. , Wright Dennis L.
Published: September 2005

We have been interested in exploiting the highly functionalized oxabicyclo[3.2.1]octadienes that are produced by the cycloaddition of furan and tetrabromocyclopropene as synthetic building blocks. As part of this program, we have prepared non‐racemic derivatives of these adducts containing an α,β‐dibromoenone moiety embedded in the bicyclic framework. Elaboration of this unit has been realized through substitution and palladium‐catalyzed cross‐coupling reactions. Formation of bicyclodecenes has also been accomplished by a chromium‐nickel‐mediated ring closure. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Seismic protection of counterweight–rails in elevators in buildings
Authors: Rildova  , Singh M. P.
Published: September 2005

The counterweight in an elevator, being the heaviest component, can often overstress the guide rails during a strong earthquake. To reduce the in‐plane counterweight response, the use of a part of the counterweight mass as a tuned mass damper in the passive and active modes is examined. The passive TMDs can reduce the stresses in the rails, but their performance can be significantly improved when they are used in the active mode. An actuator with saturation capacity less than 10% of the weight of the counterweight could reduce the critical stress response to as low a level as, or even lower than, the maximum response induced by the out‐of‐plane motion of the counterweight. Copyright © 2005 John Wiley & Sons, Ltd.
Measurement and prediction of sediment production from unpaved roads, St John, US Virgin Islands
Authors: Ramos‐Scharrón Carlos E. , MacDonald Lee H.
Published: September 2005

Excess delivery of land‐based sediments is an important control on the overall condition of nearshore coral reef ecosystems. Unpaved roads have been identified as a dominant sediment source on St John in the US Virgin Islands. An improved understanding of road sediment production rates is needed to guide future development and erosion control efforts. The main objectives of this study were to: (1) measure sediment production rates at the road segment scale; (2) evaluate the importance of precipitation, slope, contributing area, traffic, and grading on road sediment production; (3) develop an empirical road erosion predictive model; and (4) compare our measured erosion rates to other published data. Sediment production from 21 road segments was monitored with sediment traps from July 1998 to November 2001. The selected road segments had varying slopes, contributing areas, and traffic loads. Precipitation was measured by four recording rain gauges.

Sediment production was related to total precipitation and road segment slope. After normalizing by precipitation and slope, the mean sediment production rate for roads that had been graded within the last two years was 0·96 kg m−2cm−1m m−1or approximately 11 kg m−2a−1for a typical road with a 10 per cent slope and an annual rainfall of 115 cm a−1. The mean erosion rate for ungraded roads was 42 per cent lower, or 0·56 kg m−2cm−1m m−1. The normalized mean sediment production rate for road segments that had been abandoned for over fifteen years was only about 10 per cent of the mean value for ungraded roads. Sediment production was not related to traffic loads. Multiple regression analysis led to the development of an empirical model based on precipitation, slope to the 1·5 power, and a categorical grading variable.

The measured and predicted erosion rates indicate that roads are capable of increasing hillslope‐scale sediment production rates by up to four orders of magnitude relative to undisturbed conditions. The values from St John are at the high end of reported road erosion rates, a finding that is consistent with the high rainfall erosivities and steep slopes of many of the unpaved roads on St John. Other than paving, the most practical methods to reduce current erosion rates are to minimize the frequency of grading and improve road drainage. Copyright © 2005 John Wiley & Sons, Ltd.
Overbank deposition along the concave side of the Red River meanders, Manitoba, and its geomorphic significance
Authors: Brooks Gregory R.
Published: September 2005

Slow earth sliding is pervasive along the concave side of Red River meanders that impinge on Lake Agassiz glaciolacustrine deposits. These failures form elongated, low‐angled (c. 6 to 10°) landslide zones along the valleysides. Silty overbank deposits that accumulated during the 1999 spring freshet extend continuously along the landslide zones over hundreds of metres and aggraded the lower slopes over a distance 50 to 80 m from the channel margin. The aggradation is not obviously related to meander curvature or location within a meander. Along seven slope profiles surveyed in 1999 near Letellier, Manitoba, the deposits locally are up to 21 cm thick and generally thin with increasing distance from, and height above, the river. Local deposit thickness relates to distance from the channel, duration of inundation of the landslide surface, mesotopography, and variations in vegetation cover. Immediately adjacent to the river, accumulated overbank deposits are up to 4 m thick. The 1999 overbank deposits also were present along the moderately sloped (c. 23 to 27°) concave banks eroding into the floodplain, but the deposits are thinner (locally up toc. 7 cm thick) and cover a narrower area (10 to 30 m wide) than the deposits within the landslide zones. Concave overbank deposition is part of a sediment reworking process that consists of overbank aggradation on the landslide zones, subsequent gradual downslope displacement from earth sliding, and eventually reworking by the river at the toe of the landslide. The presence of the deposits dampens the outward migration of the meanders and contributes to a low rate of contemporary lateral channel migration. Concave overbank sedimentation occurs along most Red River meanders between at least Emerson and St. Adolphe, Manitoba. © Her Majesty the Queen in right of Canada.
An adaptive min–max fair bandwidth allocation scheme for cellular multimedia networks
Authors: Islam Mohammad Mahfuzul , Murshed Manzur
Published: September 2005

Depending on the flexibility in controlling the transmission rate and the differences between on‐line (real time) and off‐line transmission modes, multimedia applications can potentially include a wide range of services, with the traditional stringent quality‐of‐service (QoS) requirement at the extreme to the highly adaptive ones that can tolerate or smartly adapt to the transient fluctuations in the QoS parameters. Keeping the cellular multimedia networks efficient with low call dropping and blocking rates and high bandwidth utilisation while maintaining a fair distribution of bandwidth by synergistically addressing the differences among these services remains a significant challenge. This paper addresses this issue by developing a novel min–max fairness scheme where bandwidth is distributed with equal share only after ensuring the minimum requirements. Besides borrowing in‐use bandwidth through redistribution, this scheme also allows for using the reserved bandwidth for the offline services. Simulation results confirm the superiority of this scheme against the rate‐based borrowing and the max–min fairness schemes, the two most recent works addressing similar issues. Copyright © 2005 AEIT.
Ad hoc qualiy of service multicast routing with objection queries for admission control
Authors: Bür Kaan , Ersoy Cem
Published: September 2005

Today's handheld computing devices equipped with novel wireless network technologies can provide their users with features such as mobility, multimedia support and group communication. On the other hand, the administrative effort required to enable all these features increases beyond the level that an ordinary user can manage. Ad hoc networks, being able to quickly organise themselves without user intervention, can overcome this problem. They are also suitable for group‐oriented mobile multimedia communication. However, it is imperative for ad hoc networks to combine quality of service (QoS) and multicast routing strategies in order to utilise the wireless medium efficiently. This article defines the components of an ad hoc QoS multicast routing (AQM) protocol, which addresses this issue. AQM achieves multicast routing efficiency by tracking the availability of resources for each node within its neighbourhood. Computation of free bandwidth is based on reservations made for ongoing sessions and the allocations reported by neighbours. Current QoS status is announced at the initiation of a new session and updated periodically in the network to the extent of QoS provision. Thus, nodes are prevented from applying for membership if there is no QoS path for the session. When nodes wish to join a session with certain service requirements, a three‐phase process consisting of request, reply and reserve steps ensures that the QoS information is updated and used to select the most appropriate routes. The allowed maximum hop count of the session is taken into account in order to satisfy the delay requirements of the multimedia applications. To cope with the continuous nature of streaming multimedia, AQM nodes check the availability of bandwidth within their neighbourhood not only for themselves but within a virtual tunnel of nodes. Objection queries are issued prior to reservation to avoid excessive resource usage due to allocations made by nodes which cannot detect each other directly. New performance metrics are introduced to evaluate the efficiency of AQM regarding the satisfaction level of individual members as well as the success rate of sessions. Simulation results show that, by applying novel QoS management techniques, AQM significantly improves multicast efficiency for members as well as for sessions. Copyright © 2005 AEIT.
Comparisons of three blind channel estimation methods for CDMA systems from array signal processing perspectives
Authors: Liu Tsung‐Hsien , Li Yao‐Chieh , Chang Chih‐Chun
Published: September 2005

We study blind channel estimation in code division multiple access systems from array signal processing perspective. As there are three direction of arrival estimation methods in array signal processing, we formulate three corresponding blind channel estimation methods in a framework, although two of which have already been reported. From our analysis and simulations, the constrained and subspace methods for blind channel estimation outperforms the conventional method. The conventional method is less computationally complex, and is suitable for the scenario where only few users exist and where good power control is taken care of. The constrained and subspace methods are shown to be near‐far resistant and robust to intercell interference. Copyright © 2005 AEIT.
Round‐robin wavelength assignment: a new packet sequence criterion in optical packet switching SCWP networks
Authors: Pavón‐Mariño P. , González‐Castaño F. J. , García‐Haro Joan
Published: September 2005

The WASPNET project proposed a packet sequence criterion to preserve end‐to‐end packet order in optical packet switching (OPS) networks controlled by the scattered wavelength path (SCWP) operational mode. This paper shows that this packet ordering methodology causes performance impairments, related to unbalanced wavelength usage in fibre links. This skewed usage is inherent to the WASPNET sequencing criterion. As a solution, a round‐robin sequence criterion is proposed. The presented technique eliminates non‐uniform wavelength utilisation in fibre links for any traffic pattern, as well as the performance impairments associated. We also propose an optimum scheduling algorithm for OPS output‐buffered switch fabrics, which preserves packet order by following the new sequencing criterion. Copyright © 2005 AEIT.
Synthesisation of pulse shaping waveforms for spectral efficient digital modulations: some practical approaches
Authors: Chen Hsiao‐Hwa , Cai Cheng‐Hsien , Chao Chien‐Yao , Lin Yu‐Hsin
Published: September 2005

Bandwidth efficiency of all digital modulations is associated closely with baseband pulse shaping waveforms (PSW's) before carrier modulation. Traditional PSW designing approaches usually work in a way such that the design of PSW's in the time domain hardly reveals a direct connection with their spectral characteristics. In other words, designing process of the PSW's offers too little degree‐of‐freedom to control spectral properties of the resultant signals. This paper will present a methodology, based on which several new PSW synthesising approaches, including time‐domain convolution (TDC), steepest sidelobe roll‐off (SSR) and zero‐point insertion (ZPI) methods, will be proposed to design different PSW's with controllable spectral characteristics, such as sidelobe roll‐off rate, main lobe width and null positions in their power spectral density functions. In particular, the SSR and ZPI methods are based on a truncated cosine function series, which can be further generalised to use other seed functions. The results show that the approaches can help us to generate a PSW database containing a wide collection of promising PSW's to suit for diverse wireless applications, such as traditional digital modems as well as emerging ultra‐wideband systems. Copyright © 2005 AEIT.
Meshless numerical simulation for fully nonlinear water waves
Authors: Wu Nan‐Jing , Tsay Ting‐Kuei , Young D. L.
Published: September 2005

A meshless numerical model for nonlinear free surface water wave is presented in this paper. An approach of handling the moving free surface boundary is proposed. Using the fundamental solution of the Laplace equation as the radial basis functions and locating the source points outside the computational domain, the problem is solved by collocation of only a few boundary points. Present model is first applied to simulate the generation of periodic finite‐amplitude waves with high wave‐steepness and then is employed to simulate the modulation of monochromatic waves passing over a submerged obstacle. Good agreements are observed as compared with experimental data and other numerical models. Copyright © 2005 John Wiley & Sons, Ltd.
Mediation ofin vivo glucose sensor inflammatory response via nitric oxide release
Authors: Gifford Raeann , Batchelor Melissa M. , Lee Youngmi , Gokulrangan Giridharan , Meyerhoff Mark E. , Wilson George S.
Published: September 2005

In vivo glucose sensor nitric oxide (NO) release is a means of mediating the inflammatory response that may cause sensor/tissue interactions and degraded sensor performance. The NO release (NOr) sensors were prepared by doping the outer polymeric membrane coating of previously reported needle‐type electrochemical sensors with suitable lipophilic diazeniumdiolate species. The Clarke error grid correlation of sensor glycemia estimates versus blood glucose measured in Sprague‐Dawley rats yielded 99.7% of the points for NOr sensors and 96.3% of points for the control within zones A and B (clinically acceptable) on Day 1, with a similar correlation for Day 3. Histological examination of the implant site demonstrated that the inflammatory response was significantly decreased for 100% of the NOr sensors at 24 h. The NOr sensors also showed a reduced run‐in time of minutes versus hours for control sensors. NO evolution does increase protein nitration in tissue surrounding the sensor, which may be linked to the suppression of inflammation. This study further emphasizes the importance of NO as an electroactive species that can potentially interfere with glucose (peroxide) detection. The NOr sensor offers a viable option for in vivo glucose sensor development. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Effects of synergistic reinforcement and absorbable fiber strength on hydroxyapatite bone cement
Authors: Zhang Yu , Xu Hockin H.K.
Published: September 2005

Approximately a million bone grafts are performed each year in the United States, and this number is expected to increase rapidly as the population ages. Calcium phosphate cement (CPC) can intimately adapt to the bone cavity and harden to form resorbable hydroxyapatite with excellent osteoconductivity and bone‐replacement capability. The objective of this study was to develop a strong CPC using synergistic reinforcement via suture fibers and chitosan, and to determine the fiber strength–CPC composite strength relationship. Biopolymer chitosan and cut suture filaments were randomly mixed into CPC. Both suture filaments and composite were immersed in a physiological solution. After 1‐day immersion, cement flexural strengths (mean ± SD;n= 6) were: (2.7 ± 0.8) MPa for CPC control; (11.2 ± 1.0) MPa for CPC–chitosan; (17.7 ± 4.4) MPa for CPC–fiber composite; and (40.5 ± 5.8) MPa for CPC–chitosan–fiber composite. They are significantly different from each other (Tukey's at 0.95). The strength increase from chitosan and fiber together in CPC was much more than that from either fiber or chitosan alone. The composite strength became (9.8 ± 0.6) MPa at 35‐day immersion and (4.2 ± 0.7) MPa at 119 days, comparable to reported strengths for sintered porous hydroxyapatite implants and cancellous bone. After suture fiber dissolution, long macropore channels were formed in CPC suitable for cell migration and tissue ingrowth. A semiempirical relationship between suture fiber strengthSFand composite strengthSCwere obtained:SC= 14.1 + 0.047SF, withR= 0.92. In summary, this study achieved substantial synergistic effects by combining random suture filaments and chitosan in CPC. This may help extend the use of the moldable,in situhardening hydroxyapatite to moderate stress‐bearing orthopedic applications. The long macropore channels in CPC should be advantageous for cell infiltration and bone ingrowth than conventional random pores and spherical pores. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Functional activity of insulinoma cells (INS‐1E) and pancreatic islets cultured in agarose cryogel sponges
Authors: Bloch K. , Lozinsky V. I. , Galaev I. Yu. , Yavriyanz K. , Vorobeychik M. , Azarov D. , Damshkaln L. G. , Mattiasson B. , Vardi P.
Published: September 2005

Here, we describe the preparation, structure, and properties of cryogel sponges, which represent a new type of macroporous biomaterial for tissue engineering. Cryogels were produced through freeze–thawing techniques, either from agarose alone or from agarose with grafted gelatin. The aim of this study was to evaluate agarose cryogel sponges as scaffolds for culturing both isolated pancreatic islets and insulinoma cells (INS‐1E). In order to evaluate the effect of cell entrapment in artificial scaffolds, cell function reflected by insulin secretion and content was studied in cells cultivated for a 2‐week period either in culture plastic plates or in cryogel sponge disks. Our results show that tumor‐derived INS‐1E cells grown either on plastic or on cryogels do not differ in their proliferation, morphology, insulin release, and intracellular insulin content. However, isolated pancreatic islets cultivated on cryogels sponge show 15‐fold higher basal insulin secretion at 3.0 mM glucose than islets cultivated on plastic plates and fail to respond to stimulation with 16.7 mM glucose. In addition, these islets have about 2‐fold lower insulin content compared to those grown in plastic plates. It is possible that the cell dysfunction noted in these in vitro experiments is due to the effect of the limited oxygen supply to the islets cultivated in cryogel sponge. Further in vivo studies are needed to clarify the nature of such an observation since according to previous reports, agarose and gelatin induce new vessel formation supporting enhanced oxygen supply. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Evaluations of blood compatibility via protein adsorption treatment of the vascular scaffold surfaces fabricated with polylactide and surface‐modified expanded polytetrafluoroethylene for tissue engineering applications
Authors: Choi Yoon Jeong , Choung Sung Kwang , Hong Choong Man , Shin In Soo , Park Sue Nie , Hong Seung Hwa , Park Han Ki , Park Young Hwan , Son Youngsook , Noh Insup
Published: September 2005

Blood compatibility was evaluated by short‐term in vitro blood perfusion on candidate vascular scaffold surfaces of a biodegradable, porous polylactide scaffold and a chemically surface‐modified expanded polytetrafluoroethylene (ePTFE) over a clinical ePTFE, by measuring blood cell adhesion either directly or after adsorption treatment with albumin and fibrinogen. The results indicated that the extent of blood cell adhesion was affected by scaffold surface properties and pre‐adsorption of proteins such as fibrinogen and albumin. Surface morphologies and porosity of the scaffolds were characterized by scanning electron microscopy and porosimetry, and the amount of fibrinogen and albumin adsorbed on the scaffolds was measured and verified by employing radiolabeled C14 albumin and I125 fibrinogen by a scintillation counter and a gamma counter, respectively. Even though treatment of fibrinogen adsorption on the samples in advance led to higher induction of blood cell adhesion than those with no fibrinogen adsorption, the polylactide scaffold surface itself induced highest amount of the adhered blood cells in this study judged by analyses of their surface area. These results would be employed as guidance in determining a choice of the implant methods, in vitro versus in vivo tissue engineering, of the novel chemically modified ePTFE and the biodegradable polylactide scaffolds. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Solution‐mediated effect of bioactive glass in poly (lactic‐co‐glycolic acid)–bioactive glass composites on osteogenesis of marrow stromal cells
Authors: Yao Jun , Radin Shula , Reilly Gwendolen , Leboy Phoebe S. , Ducheyne Paul
Published: September 2005

A previous study demonstrated that the incorporation of bioactive glass (BG) into poly (lactic‐co‐glycolic acid) (PLGA) can promote the osteoblastic differentiation of marrow stromal cells (MSCs) on PLGA by promoting the formation of a calcium–phosphate‐rich layer on its surface. To further understand the mechanisms underlying the osteogenic effect of PLGA‐BG composite scaffolds, whether solution‐mediated factors derived from composite scaffolds/hybrids can promote osteogenesis of marrow stromal cells was tested. The dissolution product from PLGA‐30%BG scaffold stimulated osteogenesis of MSCs, as was confirmed by increased mRNA expression of osteoblastic markers such as osteocalcin (OCN), alkaline phosphatase (ALP), and bone sialoprotein (BSP). The three‐dimensional structure of the scaffolds may contribute to the production of cell‐derived factors that promoted distant MSC differentiation. Thus PLGA‐BG composites demonstrate significant potential as a bone‐replacement material. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Self‐organized nanotubular oxide layers on Ti‐6Al‐7Nb and Ti‐6Al‐4V formed by anodization in NH4F solutions
Authors: Macak Jan M. , Tsuchiya Hiroaki , Taveira Luciano , Ghicov Andrei , Schmuki Patrik
Published: September 2005

The present work reports the fabrication of self‐organized porous oxide‐nanotube layers on the biomedical titanium alloys Ti‐6Al‐7Nb and Ti‐6Al‐4V by a simple electrochemical treatment. These two‐phase alloys were anodized in 1M (NH4)2SO4 electrolytes containing 0.5 wt % of NH4F. The results show that under specific anodization conditions self‐organized porous oxide structures can be grown on the alloy surface. SEM images revealed that the porous layers consist of arrays of single nanotubes with a diameter of 100 nm and a spacing of 150 nm. For the V‐containing alloy enhanced etching of the β phase is observed, leading to selective dissolution and an inhomogeneous pore formation. For the Nb‐containing alloy an almost ideal coverage of both phases is obtained. According to XPS measurements the tubes are a mixed oxide with an almost stoichiometric oxide composition, and can be grown to thicknesses of several hundreds of nanometers. These findings represent a simple surface treatment for Ti alloys that has high potential for biomedical applications. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Spatially controlled co‐culture of neurons and glial cells
Authors: Yang In Hong , Co Carlos C. , Ho Chia‐Chi
Published: September 2005

The ability to create and maintain neuron and glial cell co‐cultures is important for neuronal regeneration as well as for fundamental studies on neuron and glial cell interactions. We demonstrate here a method for spatially controlling the arrangement of neurons and glial cells. Line patterns of cell resistant, poly(oligoethyleneglycol methacrylate‐co‐methacrylic acid), was microcontact printed on various substrates to spatially control the attachment of neurons. Neuron‐like cells, PC12 and SH‐SY5Y cells, were confined within the unprinted line patterns and extended neurites along the line patterns. Subsequent attachment of glial cells was accomplished by converting the originally cell‐resistant line patterns of poly(oligoethyleneglycol methacrylate‐co‐methacrylic acid) to cell adhesive by electrostatic adsorption of cationic poly‐lysine, chitosan, or poly(ethyleneimine). This method for creating patterned co‐cultures of neuron and glial cells provides a useful tool for investigating neuron–glial cell interactions and has potential applications in the repair or regeneration of nervous systems. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
The role of bivalent metals in hydroxyapatite structures as revealed by molecular modeling with the HyperChem software
Authors: Gutowska Izabela , Machoy Zygmunt , Machaliński Bogusław
Published: September 2005

Hydroxyapatite, the major component of bone, demonstrates significant reactivity with metals. Knowledge of spatial structure and energy data of the molecule helps understand the binding of metals by hydroxyapatite and elucidate the chemical and physical properties of such complexes. We used HyperChem software (Hypercube Inc.) to analyze the structure of hydroxyapatite when the central calcium atom is replaced by one of the metal ions (Mg, Cu, Zn, Fe, Cr, Mn) marked by us in bone. Our results show that hetero‐ionic exchange affects composition and leads to deformation of hydroxyapatite crystals. Replacement was accompanied by changes in bond lengths between oxygen and calcium atoms in the hydroxyapatite molecule and by displacement of groups of atoms surrounding the central calcium atom. The use of molecular modeling as a computational tool enabled a preliminary and theoretical understanding of chemical structure without the need for laboratory tests. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Fluorinated diamond‐like carbon as antithrombogenic coating for blood‐contacting devices
Authors: Hasebe Terumitsu , Shimada Atsushi , Suzuki Tetsuya , Matsuoka Yoshiaki , Saito Toshiya , Yohena Satoshi , Kamijo Aki , Shiraga Nobuyuki , Higuchi Mutsumi , Kimura Kanako , Yoshimura Hirokuni , Kuribayashi Sachio
Published: September 2005

Diamond‐like carbon (DLC) is being considered for widespread clinical use as a surface coating for cardiovascular devices. We synthesized fluorinated DLC (F‐DLC) coatings in order to create a more hydrophobic surface with improved antithrombogenicity and flexibility when compared with conventional DLC coatings by combining the inertness of DLC films with the advantage of fluorination. The purpose of this study was to evaluate the in vitro hemocompatibility and in vivo biocompatibility of the F‐DLC coating for medical devices. The in vitro whole blood model confirmed that platelet loss was lower in the F‐DLC group than in the noncoated group (SUS316L), which suggests the adhesion of a smaller number of platelets to F‐DLC‐coated materials. Furthermore, the biomarkers of mechanically induced platelet activation (beta‐thromboglobulin) and activated coagulation (thrombin‐antithrombin‐three complex) were markedly reduced in the F‐DLC‐coated group. In vivo rat implant model studies revealed no excessive local and systemic inflammatory responses in the F‐DLC group. The thickness of the fibrous tissue capsule surrounding the F‐DLC‐coated disk was almost equal to that of the noncoated SUS316L disk, which has the favorable biocompatibility for metallic implant materials. F‐DLC coating thus appears to be a promising candidate for use as a coating material in blood‐contacting devices. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Optimization of amino group density on surfaces of titanium dioxide nanoparticles covalently bonded to a silicone substrate for antibacterial and cell adhesion activities
Authors: Okada Masahiro , Yasuda Shoji , Kimura Tsuyoshi , Iwasaki Mitsunobu , Ito Seishiro , Kishida Akio , Furuzono Tsutomu
Published: September 2005

A composite consisting of titanium dioxide (TiO2) particle, the surface of which was modified with amino groups, and a silicone substrate through covalent bonding at their interface was developed, and antibacterial and cell adhesion activities of the composite were evaluated. The density of the amino groups on the TiO2 particle surface was controlled by the reaction time of the modification reaction. The degradation rate of CH3CHO in the presence of the TiO2 particles under UV irradiation decreased with an increase in the amino group density on the TiO2 surface. On the other hand, the number of L929 cells adhering on the TiO2/silicone composite increased with an increase in the amino group density. From the above two results, the optimum density of amino groups for both photoreactivity and cell adhesiveness was estimated to be 2.0–4.0 molecules/nm2. The optimum amino group‐modified TiO2/silicone composite sheet (amino group density, 3.0 molecules/nm2) showed an effective antibacterial activity for Escherichia coli bacteria under UV irradiation. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Gender‐specific differences in electromyographic changes and perceived pain induced by experimental muscle pain during sustained contractions of the upper trapezius muscle
Authors: Ge Hong‐You , Arendt‐Nielsen Lars , Farina Dario , Madeleine Pascal
Published: September 2005

The aim of the study was to investigate gender‐specific differences in the pain‐induced alterations of muscle activity during sustained contractions of the upper trapezius muscle. Surface electromyographic (EMG) signals were recorded bilaterally from the upper trapezius muscles of healthy volunteers (10 men and 9 women). The subjects held the arms at 90° abduction for 5 s (short contraction) and 3 min (sustained contraction). These contractions were performed before, during, and after injection of 0.5 ml of hypertonic saline (5.8%) bilaterally in the upper trapezius muscles. Injection of isotonic saline (0.9%) served as control. The root mean square (RMS) and mean power frequency (MPF) were computed from the EMG signals and normalized to the values obtained during maximal voluntary contractions. In the short contractions, injection of hypertonic saline, but not isotonic saline, induced a less pronounced decrease in RMS in women than men, and a significant decrease in MPF in men but not women. In the sustained contractions, RMS slope increased and MPF slope decreased (less negative) with muscle pain in men but not women. It was concluded that the pain‐induced changes in motor control strategies during sustained contractions differ in men and women, which may partly explain gender differences in the incidence of musculoskeletal pain. Muscle Nerve, 2005
Distribution network design: Selection and sizing of congested connections
Authors: Huang Simin , Batta Rajan , Nagi Rakesh
Published: September 2005

This paper focuses on certain types of distribution networks in which commodity flows must go through connections that are subject to congestion. Connections serve as transshipment and/or switching points and are modeled as M/G/1 queues. The goal is to select connections, assign flows to the connections, and size their capacities, simultaneously. The capacities are controlled by both the mean and the variability of service time at each connection. We formulate this problem as a mixed integer nonlinear optimization problem for both the fixed and variable service rate cases. For the fixed service rate case, we prove that the objective function is convex and then develop an outer approximation algorithm. For the variable service rate case, both mean and second moment of service time are decision variables. We establish that the utilization rates at the homogeneous connections are identical for an optimal solution. Based on this key finding, we develop a Lagrangian relaxation algorithm. Numerical experiments are conducted to verify the quality of the solution techniques proposed. The essential contribution of this work is the explicit modeling of connection capacity (through the mean and the variability of service time) using a queueing framework. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.
Multiscale modelling of particle debonding in reinforced elastomers subjected to finite deformations
Authors: Matouš Karel , Geubelle Philippe H.
Published: September 2005

Interfacial damage nucleation and evolution in reinforced elastomers subjected to finite strains is modelled using the mathematical theory of homogenization based on the asymptotic expansion of unknown variables. The microscale is characterized by a periodic unit cell, which contains particles dispersed in a blend and the particle matrix interface is characterized by a cohesive law. A novel numerical framework based on the perturbed Petrov–Galerkin method for the treatment of nearly incompressible behaviour is employed to solve the resulting boundary value problem on the microscale and the deformation path of a macroscale particle is predefined as in the micro‐history recovery procedure. A fully implicit and efficient finite element formulation, including consistent linearization, is presented. The proposed multiscale framework is capable of predicting the non‐homogeneous micro‐fields and damage nucleation and propagation along the particle matrix interface, as well as the macroscopic response and mechanical properties of the damaged continuum. Examples are considered involving simple unit cells in order to illustrate the multiscale algorithm and demonstrate the complexity of the underlying physical processes. Copyright © 2005 John Wiley & Sons, Ltd.
Use of equivalent mass method for free vibration analyses of a beam carrying multiple two‐dof spring–mass systems with inertia effect of the helical springs considered
Authors: Wu Jia‐Jang
Published: September 2005

This paper investigates the free vibration characteristics of a beam carrying multiple two‐degree‐of‐freedom (two‐dof) spring–mass systems (i.e. the loaded beam). Unlike the existing literature to neglect the inertia effect of the helical springs of each spring–mass system, this paper takes the last inertia effect into consideration. To this end, a technique to replace each two‐dof spring–mass system by a set of rigidly attached equivalent masses is presented, so that the free vibration characteristics of a loaded beam can be predicted from those of the same beam carrying multiple rigidly attached equivalent masses. In which, the equation of motion of the loaded beam is derived analytically by means of the expansion theorem (or the mode superposition method) incorporated with the natural frequencies and the mode shapes of the bare beam (i.e. the beam carrying nothing). In addition, the mass and stiffness matrices including the inertia effect of the helical springs of a two‐dof spring–mass system, required by the conventional finite element method (FEM), are also derived. All the numerical results obtained from the presented equivalent mass method (EMM) are compared with those obtained from FEM and satisfactory agreement is achieved. Because the equivalent masses of each two‐dof spring–mass system are dependent on the magnitudes of its lumped mass, spring constant and spring mass, the presented EMM provides an effective technique for evaluating the overall inertia effect of the two‐dof spring–mass systems attached to the beam. Furthermore, if the total number of two‐dof spring–mass systems attached to the beam is large, then the order of the overall property matrices for the equation of motion of the loaded beam in EMM is much less than that in FEM and the computer storage memory required by the former is also much less than that required by the latter. Copyright © 2005 John Wiley & Sons, Ltd.