bluuebunny/crossref_metadata_2025 huggingface dataset:
How long does a mindfulness‐based stress reduction program need to be? A review of class contact hours and effect sizes for psychological distress
Authors: Carmody James , Baer Ruth A.
Published: March 2009

The mindfulness‐based stress reduction (MBSR) program was designed to be long enough for participants to grasp the principles of self‐regulation through mindfulness and develop skill and autonomy in mindfulness practice. It traditionally consists of 26 hours of session time including eight classes of 2‐1/2 hours and an all‐day class. The circumstances of some groups exclude them from participating in this standard form and a number of trials have evaluated programs with abbreviated class time. If lower program time demands can lead to similar outcomes in psychological functioning, it would support their utility in these settings and might lead to greater participation. However, the effect of variation in class hours on outcomes has not been systematically studied. To obtain preliminary information related to this question we examined effect sizes for psychological outcome variables in published studies of MBSR, some of which had adapted the standard number of class hours. The correlation between mean effect size and number of in‐class hours was nonsignificant for both clinical and nonclinical samples and suggests that adaptations that include less class time may be worthwhile for populations for whom reduction of psychological distress is an important goal and for whom longer time commitment may be a barrier to their ability or willingness to participate. However, the standard MBSR format has accrued the most empirical support for its efficacy and session time may be important to the development of other kinds of program outcomes. The result points to the importance of empirical studies systematically examining this question. © 2009 Wiley Periodicals, Inc. J Clin Psychol 65: 1–12, 2009.
Activation of GABA‐A receptor ameliorates homocysteine‐induced MMP‐9 activation by ERK pathway
Authors: Tyagi Neetu , Gillespie William , Vacek Jonathan C. , Sen Utpal , Tyagi Suresh C. , Lominadze David
Published: March 2009

Hyperhomocysteinemia (HHcy) is a risk factor for neuroinflammatory and neurodegenerative diseases. Homocysteine (Hcy) induces redox stress, in part, by activating matrix metalloproteinase‐9 (MMP‐9), which degrades the matrix and leads to blood–brain barrier dysfunction. Hcy competitively binds to γ‐aminbutyric acid (GABA) receptors, which are excitatory neurotransmitter receptors. However, the role of GABA‐A receptor in Hcy‐induced cerebrovascular remodeling is not clear. We hypothesized that Hcy causes cerebrovascular remodeling by increasing redox stress and MMP‐9 activity via the extracellular signal‐regulated kinase (ERK) signaling pathway and by inhibition of GABA‐A receptors, thus behaving as an inhibitory neurotransmitter. Hcy‐induced reactive oxygen species production was detected using the fluorescent probe, 2′–7′‐dichlorodihydrofluorescein diacetate. Hcy increased nicotinamide adenine dinucleotide phosphate‐oxidase‐4 concomitantly suppressing thioredoxin. Hcy caused activation of MMP‐9, measured by gelatin zymography. The GABA‐A receptor agonist, muscimol ameliorated the Hcy‐mediated MMP‐9 activation. In parallel, Hcy caused phosphorylation of ERK and selectively decreased levels of tissue inhibitors of metalloproteinase‐4 (TIMP‐4). Treatment of the endothelial cell with muscimol restored the levels of TIMP‐4 to the levels in control group. Hcy induced expression of iNOS and decreased eNOS expression, which lead to a decreased NO bioavailability. Furthermore muscimol attenuated Hcy‐induced MMP‐9 via ERK signaling pathway. These results suggest that Hcy competes with GABA‐A receptors, inducing the oxidative stress transduction pathway and leading to ERK activation. J. Cell. Physiol. 220: 257–266, 2009. © 2009 Wiley‐Liss, Inc.
Circle graph obstructions under pivoting
Authors: Geelen Jim , Oum Sang‐il
Published: March 2009

A circle graph is the intersection graph of a set of chords of a circle. The class of circle graphs is closed under pivot‐minors. We determine the pivot‐minor‐minimal non‐circle‐graphs; there are 15 obstructions. These obstructions are found, by computer search, as a corollary to Bouchet's characterization of circle graphs under local complementation. Our characterization generalizes Kuratowski's Theorem. © 2009 Wiley Periodicals, Inc. J Graph Theory 61: 1‐11, 2009
Proper path‐factors and interval edge‐coloring of (3,4)‐biregular bigraphs
Authors: Asratian Armen S. , Casselgren Carl Johan , Vandenbussche Jennifer , West Douglas B.
Published: March 2009

An interval coloring of a graph G is a proper coloring of E(G) by positive integers such that the colors on the edges incident to any vertex are consecutive. A (3,4)‐biregular bigraph is a bipartite graph in which each vertex of one part has degree 3 and each vertex of the other has degree 4; it is unknown whether these all have interval colorings. We prove that G has an interval coloring using 6 colors when G is a (3,4)‐biregular bigraph having a spanning subgraph whose components are paths with endpoints at 3‐valent vertices and lengths in {2, 4, 6, 8}. We provide several sufficient conditions for the existence of such a subgraph. © 2009 Wiley Periodicals, Inc. J Graph Theory
On graphs with a given endomorphism monoid
Authors: Koubek Václav , Rödl Vojtěch , Shemmer Benjamin
Published: March 2009

Hedrlín and Pultr proved that for any monoid M there exists a graph G with endomorphism monoid isomorphic to M. In this paper we give a construction G(M) for a graph with prescribed endomorphism monoid M. Using this construction we derive bounds on the minimum number of vertices and edges required to produce a graph with a given endomorphism monoid for various classes of finite monoids. For example we show that for every monoid M, |M|=m there is a graph G with End(G)≃M and |E(G)|≤(1 + 0(1))m2. This is, up to a factor of 1/2, best possible since there are monoids requiring a graph with \documentclass{article}\footskip=0pc\pagestyle{empty}\begin{document}\begin{eqnarray*} && \frac{m^{2}}{2}(1 -0(1)) \end{eqnarray*}\end{document} edges.

We state bounds for the class of all monoids as well as for certain subclasses—groups, k‐cancellative monoids, commutative 3‐nilpotent monoids, rectangular groups and completely simple monoids. © 2009 Wiley Periodicals, Inc. J Graph Theory 62, 241–262, 2009
Stability for large forbidden subgraphs
Authors: Nikiforov Vladimir
Published: March 2009

In this note we strengthen the stability theorem of Erdős and Simonovits. Write Kr(s1, …, sr) for the complete r‐partite graph with classes of sizes s1, …, sr and Tr(n) for the r‐partite Turán graph of order n. Our main result is:

For all r≥2 and all sufficiently small c>0, ε>0, every graph G of sufficiently large order n with e(G)>(1−1/r−ε)n2/2 satisfies one of the conditions:

G contains a
\documentclass{article} \usepackage{amssymb}\footskip=0pc\pagestyle{empty} \begin{document} $K_{r+1} (\lfloor c\,\mbox{ln}\,n \rfloor,\ldots,\lfloor c\,\mbox{ln}\,n \rfloor,\lceil n^{{1}-\sqrt{c}}\rceil)$ \end{document};

G differs from Tr(n) in fewer than (ε1/3+c1/(3r+3))n2 edges.

Letting µ(G) be the spectral radius of G, we prove also a spectral stability theorem:

For all r≥2 and all sufficiently small c>0, ε>0, every graph G of sufficiently large order n with µ(G)>(1−1/r−ε)n satisfies one of the conditions:

G contains a \documentclass{article} \usepackage{amssymb}\footskip=0pc\pagestyle{empty} \begin{document} $K_{r+1}(\lfloor c\,\mbox{ln}\,n\rfloor,\ldots,\lfloor c\,\mbox{ln}\,n\rfloor,\lceil n^{1-\sqrt{c}}\rceil)$ \end{document};

G differs from Tr(n) in fewer than (ε1/4+c1/(8r+8))n2 edges.

© 2009 Wiley Periodicals, Inc. J Graph Theory 62: 362–368, 2009
A novel microwave‐assisted green synthesis of condensed 2‐substituted‐pyrimidin‐4(3H)‐ones under solvent‐free conditions
Authors: Jain Kishor S. , Bariwal Jitender B. , Phoujdar Manisha S. , Nagras Madhuri A. , Amrutkar Rakesh D. , Munde Manoj K. , Tamboli Riyaj S. , Khedkar Samrat A. , Khiste Rahul H. , Vidyasagar Nikhil C. , Dabholkar Vinit V. , Kathiravan M. K.
Published: March 2009

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A rapid microwave‐assisted green chemical synthesis of condensed 2‐substituted‐pyrimidin‐4(3H)‐ones 3, 4, and 5 involving the condensation of a variety of nitriles with o‐aminoesters of thiophene 2a, 2b, 2c, 2d, 2e, benzene 2f, dimethoxybenzene 2g and quinazolinone 2h in the presence of catalytic amount of HCl alone or with the Lewis acid AlCl3 under solvent‐free conditions, is described for the first time. This novel and clean one‐pot methodology, which is characterized by very short reaction times and easy workup procedures, can be exploited to generate a diverse library of condensed pyrimidine heterocycles. J. Heterocyclic Chem., (2009)
New functionalized N‐heterocyclic carbene ligands for arylation of benzaldehydes
Authors: Doğan Öznur , Gürbüz Nevin , Özdemir İsmail , Çetinkaya Bekir
Published: March 2009

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Novel functionalized 1,3‐dialkylimidazolinium salts (LHCl) as NHC precursors have been prepared and successfully applied in palladium‐catalyzed arylation of benzaldehydes. The ortho position of aromatic aldehydes was directly and selectively arylated with aryl chlorides in the presence of a catalytic system prepared in situ from Pd(OAc)2, 1,3‐dialkylimidazolinium chlorides (2a, 2b, 2c), and Cs2CO3. J. Heterocyclic Chem., (2009)
Synthesis of the hypotensive agent 8‐amino‐7‐[2‐hydroxy‐3‐morpholinopropyl]theophylline (P23) and analogs
Authors: Cegla Marek T. , Potaczek Joanna , Zylewski Marek , Strekowski Lucjan
Published: March 2009

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Synthesis of a number of 7,8‐disubstituted theophyllines including enantiomers of the hypotensive agent P23 is described. J. Heterocyclic Chem., (2009)
Meta‐substituent effects on organoiridium‐catalyzed ortho‐hydrogen isotope exchange
Authors: Heys J. Richard , Elmore Charles S.
Published: March 2009

Reports in the literature appear to differ on the effects of some C3 substituents on the relative efficiencies of isotope exchange in the nonidentical C2‐ and C6‐positions catalyzed by organoiridium complexes. Controlled experiments were conducted using a set of model substrates in attempts to clarify these effects. The results clearly showed that, in common with most previous findings, alkyl substituents at C3 reduced the rate of isotope incorporation into C2 relative to C6, as expected on steric grounds. In contrast, all substituents possessing electron lone pairs resulted in a lessening of the inhibition of C2‐vs‐C6 labeling or promoted C2 labeling to such a degree that it became faster than that at C6. NMR measurements on equimolar mixtures of active iridium complex with selected substrates revealed that the ratios of C2‐ and C6‐iridacycles present in solution correlated with the relative rates of ortho‐deuteration in the rate studies. The results of the two studies, taken together, suggest that conventional explanations for the origin of the positive meta‐effect may not be adequate for the present system. An alternative hypothesis is advanced. Copyright © 2009 John Wiley & Sons, Ltd.
Efficient syntheses of isotopically labeled PD0198961, a novel synthetic coagulation factor Xa inhibitor
Authors: Zhang Yinsheng
Published: March 2009

PD0198961 was investigated as a potent and selective inhibitor of coagulation factor Xa for the treatment of thrombotic disorders. Radioactive and stable isotope‐labeled PD0198961 were synthesized for absorption, distribution, metabolism and elimination studies of the compound in animals and for use as mass spectral internal standards in support of bioanalytical assays, respectively. [14C]PD0198961 was prepared from [14C]CuCN in four radiosynthetic steps in an overall yield of 48% with a radiochemical purity of >99%. The cyanation reaction of an aromatic bromide with inorganic [14C]cyanide as a key radiolabeling step was investigated. The deuterium‐labeling was accomplished in a different reaction sequence from the 14C labeling. This convergent process introduced stable isotope labeling via cis‐2,6‐dimethyl[2H5]piperidine, which was synthesized by catalytic hydrogenation of 2,6‐dimethylpyridine with deuterium gas. Copyright © 2009 John Wiley & Sons, Ltd.
A climatology of warm‐season mesoscale convective complexes in subtropical South America
Authors: Durkee Joshua D. , Mote Thomas L.
Published: March 2009

This study extends investigations of mesoscale convective complexes (MCCs) over subtropical South America (SSA) by describing the physical characteristics of MCCs during the austral warm season (October–May) for 1998–2007 in SSA. Within the nine warm seasons, 330 events were documented. An average of 37 MCCs occurred each warm season and reached a maximum cloud‐shield size of 256 500 km2, and lasted 14 h on average. Although 85% of the MCC population occurred over the South American continent, the remaining systems that occurred over the adjacent Atlantic Ocean were significantly larger by nearly 30%. These findings show MCCs in SSA are larger and longer‐lived than shown in previous work. Compared to the United States, MCCs in SSA are significantly larger with longer durations. Unlike the US systems, these events do not exhibit much poleward migration throughout the warm season. The highest frequency and concentration of MCC cloud shields are centred east of the Andes Mountains between 20°S and 30°S over Paraguay, northern Argentina, and southern Brazil throughout the warm season. As a result, relationships between latitude, and MCC maximum extent or duration are weak or non‐existent, respectively. There is, however, a moderate positive relationship between duration and maximum extent. Ultimately, MCCs in SSA are large, long‐lasting events that possess great potential for contributing significantly to precipitation totals across the region. Copyright © 2009 Royal Meteorological Society
T1 glottic carcinoma involving the posterior commissure
Authors: Shvero Jacob , Shvili Itzhak , Mizrachi Aviram , Shpitzer Thomas , Nageris Benny , Koren Rumelia , Hadar Tuvia
Published: March 2009

Objectives/Hypothesis:

The posterior commissure is an uncommon site of glottic carcinoma. The aim of the study was to compare the clinical and prognostic characteristics of glottic carcinoma of the posterior commissure and the vocal cords.

Study Design:

Retrospective case control study.

Methods:

The study group consisted of 40 patients aged 32 to 84 years (mean, 62.7 ± 10.7) diagnosed with T1 glottic carcinoma involving the posterior commissure from 1960 to 2008. Data on clinical features and outcome were collected from the medical files and compared with the data for 42 patients aged 30 to 87 years (mean, 64.4 ± 11.8) with T1 vocal cord carcinoma.

Results:

There were no significant differences in clinical characteristics between the groups except for the higher rate of smokers among the patients with vocal cord carcinoma (95% vs. 65%, P = .01). All patients were treated primarily with radiotherapy. Disease‐free survival in the posterior commissure carcinoma group was 76.1% after 5 years and 72.3% after 10 years, and in the vocal cord carcinoma group, 95% after 5 and 10 years (P = .012). The risk of recurrence was higher when the tumor involved the posterior commissure (hazard ratio, 8.78; 95% CI, 1.12–68.5, P = .038).

Conclusions:

T1 glottic carcinoma involving the posterior commissure has a more aggressive biological behavior and a worse prognosis than T1 glottic carcinoma of the vocal cords. Smoking, which is an important pathogenetic factor in vocal cord carcinoma, plays a lesser role in posterior commissure carcinoma. Laryngoscope, 2009
Photon‐echo quantum memory in solid state systems
Authors: Tittel W. , Afzelius M. , Chaneliére T. , Cone R.L. , Kröll S. , Moiseev S.A. , Sellars M.
Published: March 2009

Many applications of quantum communication crucially depend on reversible transfer of quantum states between light and matter. Motivated by rapid recent developments in theory and experiment, we review research related to quantum memory based on a photon‐echo approach in solid state material with emphasis on use in a quantum repeater. After introducing quantum communication, the quantum repeater concept, and properties of a quantum memory required to be useful in a quantum repeater, we describe the historical development from spin echoes, discovered in 1950, to photon‐echo quantum memory. We present a simple theoretical description of the ideal protocol, and comment on the impact of a non‐ideal realization on its quantum nature. We extensively discuss rare‐earth‐ion doped crystals and glasses as material candidates, elaborate on traditional photon‐echo experiments as a test‐bed for quantum state storage, and describe the current state‐of‐the‐art of photon‐echo quantum memory. Finally, we give a brief outlook on current research.
Experimental and numerical analyses of diffusion bonded hollow sphere structures
Authors: Winkler R. , Merkel M. , Öchsner A.
Published: March 2009

The reduction of N&V (noise and vibration) is a progressively more important objective for designers of various engineering applications. When a series of physical and mechanical requirements are touched, classic materials reach their limits. Cellular metals with their great diversity of properties open up new vistas. Metallic hollow sphere structures (MHSS) feature a new group of advanced composite materials characterised by high geometrical reproducibility leading to stable properties. In the scope of this study, vibrational analysis of sintered metallic hollow sphere structures is performed. The objective is a description of the dynamic response by numerical simulation. A detailed finite element model would exceed available resources. Therefore, a proper model with special descriptions for hollow spheres and interconnections has been developed and is presented in detail. Numerical results are compared with vibrations measured by laser scanning vibrometer and analytical analysis.
Computed tomography based finite element analysis of the thermal properties of cellular aluminium
Authors: Fiedler T. , Solórzano E. , Garcia‐Moreno F. , Öchsner A. , Belova I.V. , Murch G.E.
Published: March 2009

This work addresses the thermal finite element analysis (FE) of cellular aluminium with irregular pore structures. The used finite element models are generated with computed tomography (CT) images as a basis. Three‐dimensional brick elements of cubic shape are used. The material properties of each element are thereby defined based on corresponding pixels in computed tomography images. The proposed analysis with mapping of material properties on a regular finite element mesh is first validated on simple two dimensional models of regular geometries. The obtained results are compared to highly accurate reference solutions and analytical predictions. Subsequently, the FEM thermal analysis of closed cell Alporas® aluminium foam and open cell M‐Pore® aluminium sponge is carried out determining the effective thermal conductivities of these materials in three perpendicular directions in order to investigate the anisotropic properties of both structures. The variability in the material volume (due to meso‐inhomogeneities) has been inspected by computing different sub‐volumes of the specimens.
Numerical approaches for residual vibration free positioning of elastic robots
Authors: Bachmayer M. , Zander R. , Ulbrich H.
Published: March 2009

Today increasing the speed of moving machines with the same or even better precision can often only be realized if flexibilities are taken into account. In order to avoid a stiffer and therefore heavier structure, the flexibility must be considered in the control design. Numerical optimization approaches as well as an analytical feed forward control for linearly actuated robots like placement machines or stacker cranes are presented. These methods help to reduce the time required for positioning in dynamic automation scenarios where the structure’s elasticity is essential for achieving high positioning precision in a minimum of time. Backlash in the gear limits standard closed loop active damping controller’s capabilities in respect to the achievable damping constant. Therefore, feedforward trajectories avoiding residual vibrations are desirable to reduce the positioning time to a structural given limit.
Monitoring of oil leakage from a ship propulsion system using IR camera and wavelet analysis for prevention of health and ecology risks and engine faults
Authors: Kuzmanić I. , Šoda J. , Antonić R. , Vujović I. , Beroš S.
Published: March 2009

It is a well known fact that oil leakage from ship diesel engines is harmful both for the environment and the ship engine and therefore has to be observed and alarmed. The present paper proposes a system for overcoming described problems by installing a computer vision system. The used algorithm of pattern recognition system is based on the use of wavelet structures. Additionally, one of the problems in the system is the compensation of camera movements due to engine vibration. The compensation part of the computer vision solution is used to improve position determination. The position determination is improved more that 300 % when using farras wavelets.
Drop impact analysis of smart unmanned aerial vehicle (SUAV) landing gear and comparison with experimental data
Authors: Kong J.P. , Lee Y.S. , Han J.D. , Ahn O.S.
Published: March 2009

The dynamic behavior of the landing gear is very important, because it absorbs kinetic energy of the vertical load and reduces aircraft impact at touchdown. In this study, drop impact analyses have been conducted for SUAV’s landing gear using the explicit finite element code LS‐DYNA®. The landing gear was modeled as a flexible body and the analyses were focused on the dynamic behavior of the shock absorber, the deformation of the tire, energy analysis and the reaction load on the impact surface. Experimental results were compared with the analytical results.
Mechanical behavior analysis of sintered products of natural rubber crumb rubber (NRCR) using adhesives
Authors: Crespo J. E. , Parres F. , Nadal A.
Published: March 2009

In this work, we began by carrying out an analysis of the mechanical behaviour of sintered Natural Rubber Crumb Rubber (NRCR) optimising the temperature and compression pressure. The results obtained show an improvement in the mechanical properties of the material when the temperature and compression pressure are increased. We then mixed particles of NRCR with different percentages of adhesives with the aim of improving the mechanical performance of the sintered material. The adhesives used in this study were Latex and Polychloroprene, obtaining the best performance for the mixtures with Polychloroprene with a weight percentage of 50 %. The study was completed by an image analysis of the mixtures using a scanning electronic microscope (SEM) in order to observe the NRCR – adhesive reaction.
An anterior‐lateral thigh perforator flap on a recipient brachial‐radial vein graft for complex wound reconstruction: A case report
Authors: Romeo Marco , Cuccia Giuseppe , Manasseri Benedetto , Delia Gabriele , Risitano Giovanni , Spinelli Francesco , D'Alcontres Francesco Stagno , Colonna Michele R.
Published: March 2009

A case of challenging microsurgical reconstruction of a difficult defect in a radiated upper limb is reported. A difficult wound, with tendon and bone exposition, developed on the dorsum of the forearm in a 76‐year‐old patient; she had been radiated since almost 50 years and her left hand had also been revascularized twice with venous grafts between the humeral artery and the superficial palmar arch. After failure of a local flap, an anterior‐lateral thigh perforator flap was successfully transferred with end‐to‐side anastomoses on the arterialized venous graft. Up to date follow‐up shows a good outcome. The Authors discuss the case and review the indications for microsurgical reconstruction in difficult wounds after radiation and ischemic limb conditions. © 2009 Wiley‐Liss, Inc. Microsurgery, 2009.
Reverse flow facial artery as recipient vessel for perforator flaps
Authors: Hölzle Frank , Hohlweg‐Majert Bettina , Kesting Marco R. , Mücke Thomas , Loeffelbein Denys J. , Wolff Klaus‐Dietrich , Wysluch Andreas
Published: March 2009

In perforator flaps, anastomosis between flap and recipient vessels in the neck area is often difficult due to small vessel diameter and short pedicle. The aim of this study was to investigate whether the retrograde flow of the distal, paramandibular part of the facial artery would provide sufficient pressure and size to perfuse perforator flaps. Before and after occlusion of the contralateral facial artery, retrograde and anterograde arterial pressure was measured on both sides of the facial artery in 50 patients. The values were compared with the mean systemic arterial pressure. Diameters of facial arteries in the paramandibular region and perforator flap vessels were evaluated by morphometry. Arterial pressure in the distal facial artery with retrograde flow was 76% of the systemic arterial pressure. The latter equaled approximately the anterograde arterial pressure in the proximal end of the facial artery. Mean arterial pressure of the facial arteries decreased after proximal occlusion of the contralateral facial artery, which was not significant (P = 0.09). Mean diameter of the distal facial arteries in the mandibular region was 1.6 mm (range 1.3–2.2 mm; standard deviation 0.3 mm; n = 50), that of the perforator flap arteries 1.3 mm (0.9–2.6 mm; 0.4 mm; n = 20). Facial arteries, based on reverse flow, successfully supported all 20 perforator flaps. Retrograde pulsatile flow in the distal facial artery sustains perforator flaps even if the contralateral facial artery is occluded. Proximity of the distal facial arteries to the defect compensates for short pedicles. Matching diameters of the arteries are ideal for end‐to‐end anastomosis. © 2009 Wiley‐Liss, Inc. Microsurgery, 2009.
Face resurfacing using a cervicothoracic skin flap prefabricated by lateral thigh fascial flap and tissue expander
Authors: Li Qingfeng , Zan Tao , Gu Bin , Liu Kai , Shen Guoxiong , Xie Yun , Weng Rui
Published: March 2009

Background: Resurfacing of facial massive soft tissue defect is a formidable challenge because of the unique character of the region and the limitation of well‐matched donor site. In this report, we introduce a technique for using the prefabricated cervicothoracic skin flap for facial resurfacing, in an attempt to meet the principle of flap selection in face reconstructive surgery for matching the color and texture, large dimension, and thinner thickness (MLT) of the recipient. Materials: Eleven patients with massive facial scars underwent resurfacing procedures with prefabricated cervicothoracic flaps. The vasculature of the lateral thigh fascial flap, including the descending branch of the lateral femoral circumflex vessels and the surrounding muscle fascia, was used as the vascular carrier, and the pedicles of the fascial flap were anastomosed to either the superior thyroid or facial vessels in flap prefabrication. A tissue expander was placed beneath the fascial flap to enlarge the size and reduce the thickness of the flap. Results: The average size of the harvested fascia flap was 6.5 × 11.7 cm. After a mean interval of 21.5 weeks, the expanders were filled to a mean volume of 1,685 ml. The sizes of the prefabricated skin flaps ranged from 12 × 15 cm to 15 × 32 cm. The prefabricated skin flaps were then transferred to the recipient site as pedicled flaps for facial resurfacing. All facial soft tissue defects were successfully covered by the flaps. The donor sites were primarily closed and healed without complications. Although varied degrees of venous congestion were developed after flap transfers, the marginal necrosis only occurred in two cases. The results in follow‐up showed most resurfaced faces restored natural contour and regained emotional expression. Conclusion: MLT is the principle for flap selection in resurfacing of the massive facial soft tissue defect. Our experience in this series of patients demonstrated that the prefabricated cervicothoracic skin flap could be a reliable alternative tool for resurfacing of massive facial soft tissue defects. © 2009 Wiley‐Liss, Inc. Microsurgery, 2009.
Porosity of the wall of a Neurolac® nerve conduit hampers nerve regeneration
Authors: Meek Marcel F. , Den Dunnen Wilfred F. A.
Published: March 2009

One way to improve nerve regeneration and bridge longer nerve gaps may be the use of semipermeable/porous conduits. With porosity less biomaterial is used for the nerve conduit. We evaluated the short‐term effects of porous Neurolac® nerve conduits for in vivo peripheral nerve regeneration. In 10 male Black Hooded rats, a gap of 10 mm was bridged by a porous Neurolac® nerve conduit. Evaluation point ranged from 3 to 12 weeks. The sciatic nerve function was not measurable due to automutilation and flexion contractures. The gait‐stance duration showed no improvement with time, indicating a disturbed walking pattern. The nerve guides showed very fast degradation with swelling, fragmentation, and collapse. Furthermore, a severe foreign body reaction occurred. Nerve regeneration was severely hampered. This study showed no beneficial effects of porous Neurolac® nerve conduits when compared with previous findings with nonporous copolymeric nerve guides of a slightly different composition. © 2009 Wiley‐Liss, Inc. Microsurgery, 2009.
Effect of low‐intensity pulsed ultrasound on the expression of neurotrophin‐3 and brain‐derived neurotrophic factor in cultured Schwann cells
Authors: Zhang Hua , Lin Xin , Wan Hong , Li Jun‐Hua , Li Jia‐Mou
Published: March 2009

It is generally known that low‐intensity pulsed ultrasound (LIPUS) accelerates peripheral nerve tissue regeneration. However, the precise cellular mechanism involved is still unclear. The purpose of this study was to determine how the Schwann cells respond directly to LIPUS stimuli. Thus, we investigated the effect of LIPUS on cell proliferation, neurotrophin‐3 (NT‐3), and brain‐derived neurotrophic factor (BDNF) mRNA expression in rat Schwann cells. Schwann cells were enzymatically isolated from postnatal 1–3 day rat sciatic nerve tissue and cultured in the six‐well plate. The ultrasound was applied at a frequency of 1 MHz and an intensity of 100 mW/cm2 spatial average temporal average for 5 minutes/day. The control group was cultured in the same way but without the administration of ultrasound. Immunohistochemistry demonstrated that more than 98% of the experimental and control cells were positive for S‐100, NT‐3, and BDNF. With 5‐bromo‐2′‐deoxyuridine (BrdU) assay, the stimulated cells also exhibited an increase in the rate of cell proliferation on days 4, 7, 10, and 14. Further investigation found that mRNA expression of NT‐3 was significantly upregulated in experimental groups compared with the control 14 days after the LIPUS stimulation (the ratio of NT‐3/β‐actin was 0.56 ± 0.13 vs. 0.41 ± 0.09, P < 0.01), whereas the mRNA expression of BDNF was significantly downregulated in experimental groups compared with the control (the ratio of BDNF/β‐actin was 0.51 ± 0.05 vs. 0.60 ± 0.08, P < 0.05). These results demonstrated that the application of LIPUS promotes cell proliferation and NT‐3 gene expression in Schwann cells, and involved in the alteration of BDNF gene expression. © 2009 Wiley‐Liss, Inc. Microsurgery, 2009.
Three‐dimensional reconstruction and visualization of the median nerve from serial tissue sections
Authors: Sun Kuo , Zhang Jian , Chen Tongyi , Chen Zhongwei , Chen Zenggan , Li Zhi , Li Hua , Hu Ping
Published: March 2009

The purpose of this study was to definitively implement the three‐dimensional visualization of sensory and motor fascicles in the human median nerve by means of acetylcholinesterase (AChe) histochemical staining and under the assistance of the computer technology. One fresh human median nerve was harvested from a male adult cadaver. The median nerve was fixed at a special holder. Then, the whole holder was embedded and rapidly frozen in the liquid nitrogen. The processed median nerve was then cut coronally every 100 μm at a 20 μm thickness along its long axis in a sliding freezing microtome. The total number of sections was 4,650 slices. All sections were stained with the AChe histochemical method. The stained sections were scanned and saved as Joint Photographic Experts Group files. These images with positively and negatively stained sections were acquired to an Intel dual Pentium computer. The Adobe Photoshop CS2 software was used to compare the reference points of images before and after staining. The two‐dimensional intraneural microstructure database of median nerve was then acquired. A software of 3D nerve visualization system was developed. With the 3D nerve visualization system, the 3D visualization result of intraneural microstructure of median nerve was created. The findings may provide more accurate and detailed anatomic information for nerve repairs, specifically for the fascicular nerve repairs. The 3D nerve visualization technique may have potential for future studies of topography of peripheral nerve. © 2009 Wiley‐Liss, Inc. Microsurgery, 2009.
Global regular solutions to Cahn–Hilliard system coupled with viscoelasticity
Authors: Pawłow Irena , Zaja̧czkowski Wojciech M.
Published: March 2009

In this paper we prove the existence and uniqueness of a global in time, regular solution to the Cahn–Hilliard system coupled with viscoelasticity. The system arises as a model, regularized by a viscous damping, of phase separation process in a binary deformable alloy quenched below a critical temperature.

The key tools in the analysis are estimates of absorbing type with the property of exponentially time‐decreasing contribution of the initial data. Such estimates allow not only to prolong the solution step by step on the infinite time interval but also to conclude the existence of an absorbing set. Copyright © 2009 John Wiley & Sons, Ltd.
Unequivocal assignments of flavonoids from Tephrosia sp. (Fabaceae)
Authors: Arriaga A. M. C. , Lima J. Q. , Vasconcelos J. N. , de Oliveira M. C. F. , Andrade‐Neto M. , Santiago G. M. P. , Uchoa D. E. A. , Malcher G. T. , Mafezoli J. , Braz‐Filho R.
Published: March 2009

1H and 13C NMR chemical shifts of praecansone B, pongaflavone and dehydrorotenone isolated from Tephrosia egregia Sandw and obovatin from T. toxicaria Pers. were unambiguously assigned by 1D and 2D NMR experiments including 1H, 1H COSY, gHMQC and gHMBC, allowing the correction of literature assignments.Copyright © 2009 John Wiley & Sons, Ltd.
Guaranteed energy error bounds for the Poisson equation using a flux‐free approach: Solving the local problems in subdomains
Authors: Parés N. , Santos H. , Díez P.
Published: March 2009

A method to compute guaranteed upper bounds for the energy norm of the exact error in the finite element solution of the Poisson equation is presented. The bounds are guaranteed for any finite element mesh however coarse it may be, not just in the asymptotic regime. The bounds are constructed by employing a subdomain‐based a posteriori error estimate which yields self‐equilibrated residual loads in stars (patches of elements). The proposed approach is an alternative to standard equilibrated residual methods providing sharper bounds. The use of a flux‐free error estimator improves the effectivities of the upper bounds for the energy while retaining the certainty of the bounds. Copyright © 2009 John Wiley & Sons, Ltd.
Natural fiber hybrid composites—A comparison between compression molding and resin transfer molding
Authors: Idicula Maries , Sreekumar P.A. , Joseph Kuruvilla , Thomas Sabu
Published: March 2009

Short randomly oriented intimately mixed banana and sisal hybrid fiber‐reinforced polyester composites having varying volume fraction of fiber were fabricated by compression molding (CM) and resin transfer molding (RTM) techniques by keeping the volume ratio of banana and sisal, 1:1. The static mechanical properties such as tensile, flexural, and impact behavior were studied. The dynamic mechanical properties were also evaluated. Resin transfer molded composites showed enhanced static and dynamic mechanical properties, compared with the compression molded samples. To analyze the fracture surface morphology of the composites, scanning electron microscopy (SEM) was also performed. Water sorption studies revealed that the water uptake of RTM fabricated composites was lower than that of the compression molded composites. The void content of the RTM composites was also found to be lower than that of the other one. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers
Tribological properties of PTFE‐filled thermoplastic polyimide at high load, velocity, and temperature
Authors: Samyn Pieter , Schoukens Gustaaf
Published: March 2009

The effect of 20 wt% polytetrafluoroethylene (PTFE) fillers on the friction and wear properties of thermoplastic polyimides (TP) are investigated, under dry sliding in line contact against steel under 50 to 200 N, 0.3 to 1.2 m/s, and 60 to 260°C. Besides the lubricating mechanisms of PTFE based on mechanical shear, the thermal and tribophysical interactions in the sliding interface are considered in this research by using thermoanalytical measurements, Raman spectroscopy, and calculating the maximum polymer sliding temperatureT*. The effect of hydrolysis of the TP bulk material, causing high friction at 100 to 140°C, is covered by PTFE. A transition atpv‐values 2.2 MPa m/s (T* = 120°C) is due to thermally controlled sliding of PTFE, while a transition atpv‐values 3.2 MPa m/s (T* = 180°C) remains controlled by degradation of the TP bulk material into monomer fractions. The reduced coefficient of friction in the presence of PTFE leads to smaller degradation and orientation of the molecular back‐bone and side‐chains within the TP structure. The formation of a homogeneously mixed transfer film is only observed at 180 to 260°C. The PTFE forms a fibrillar structure during wear at high sliding velocities, while they wear as separate particles at high normal loads. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers
Experimental characterization and numerical simulation of the humidity absorption process in glass reinforced composites under dissymmetric exposure conditions
Authors: Ben Daly H. , Harchay M. , Belhadjsalah H. , Boukhili R.
Published: March 2009

This article investigates the dissymmetrical water absorption process in E‐glass fiber reinforced polyester composites containing fillers and low profile additives. Two different cases of dissymmetrical exposures to water were considered. In the first case, only one side of the aged specimen was exposed to water at different temperatures, the other side was exposed to air. In the second case, both sides were exposed to water, but at different temperatures on each side. The moisture diffusivity and the maximum moisture content reached by the composites were determined using the gravimetric test method. In the first case of the dissymmetrical immersion, the temperature inside the aged specimen was found to be almost constant and the kinetic of the water diffusion was found to obey perfectly the one‐dimensional Fick's second law. In the second case, the specimen temperature varies from one side to the other, thus preventing the use of Fick's laws. Alternatively, the use of the finite element code ABAQUS provided an excellent agreement between the experimental and simulated results in both cases of dissymmetrical immersions, as well as in the case of symmetrical immersion where the two sides were exposed to the same environmental conditions. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers
Effect of fiber orientation on viscoelastic properties of polymer matrix composites subjected to thermal cycles
Authors: Coban Onur , Bora Mustafa Ozgur , Sinmazcelik Tamer , Gunay Volkan
Published: March 2009

Fibers in polymer composites can be designed in various orientations for their usage in service life. Various fiber orientated polymer composites, which are used in aeroplane and aerospace applications, are frequently subjected to thermal cycles because of the changes in body temperatures at a range of −60 to 150°C during flights. It is an important subject to investigate the visco‐elastic properties of the thermal cycled polymer composite materials which have various fiber orientations during service life. Continuous fiber reinforced composites with a various fiber orientations are subjected to 1,000 thermal cycles between the temperatures of 0 and 100°C. Dynamic mechanic thermal analysis (DMTA) experiments are carried out by TA Q800 type equipment. The changes in glass transition temperature (Tg), storage modulus (E′), loss modulus (E′′) and loss factor (tan δ) are inspected as a function of thermal cycles for different fiber orientations. It was observed that thermal and dynamic mechanical properties of the polymer composites were remarkably changed by thermal cycles. It was also determined that the composites with [45°/−45°]s fiber orientation presented the lowest dynamic mechanical properties. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Experimental investigation on the abrasive wear behavior of nanoclay‐filled EVA/LDPE composites
Authors: Kumar B.N. Ravi , Suresha B. , Sailaja R.R.N. , Venkataramareddy M.
Published: March 2009

The article presents the results of experimental investigation on three‐body abrasive wear behavior of nanoclay‐filled EVA/LDPE (NC‐EVA/LDPE) composites. NC‐EVA/LDPE composites with and without compatibilizer were prepared by Brabender Co‐Twin extruder (Make: CMEI, Model: 16CME, SPL) and poly(ethylene‐co‐glycidyl methacrylate) was used as the compatibilizer. The mechanical properties were evaluated using Universal testing machine. In three‐body wear tests, silica sand particles of size 200–250 μm were used as dry and loose abrasives. Three‐body abrasive wear studies were carried out using dry sand/rubber wheel abrasion test rig. The effect of abrading distance on the abrasive wear behavior of neat EVA, EVA/LDPE, and NC‐EVA/LDPE composites was reported. The results showed that the wear volume loss is increased with increase in abrading distance and the specific wear rate decreased with increase in abrading distance. However, the presence of nanoclay filler in EVA/LDPE composite showed a promising trend. Abrasive wear volume of the composites was correlated with mechanical properties such as hardness, tensile strength, and percentage elongation. However, higher weight percentage of LDPE in EVA increased the wear rate. The results indicate that NC‐EVA/LDPE with compatibilizer composite exhibits good abrasive wear resistance compared with NC‐EVA/LDPE without compatibilizer. Attempts to explain these differing trends are made in this work by analyzing the features observed on the worn surface samples by employing scanning electron microscopy (SEM). POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Influence of alkali‐treated fibers on the mechanical properties and machinability of roselle and sisal fiber hybrid polyester composite
Authors: Athijayamani A. , Thiruchitrambalam M. , Natarajan U. , Pazhanivel B.
Published: March 2009

In this work, the alkali‐treated roselle and sisal fibers were used as reinforcement fillers for thermosetting matrix with aim of obtaining better mechanical properties and machinability of natural fiber hybrid polyester composite. However, their mechanical properties and machinability were compared with untreated fiber composites. The roselle and the sisal fibers were subjected to a 10% sodium hydroxide solution treatment at different duration of 2, 4, 6, and 8 h. Besides, the fractured surfaces of composite specimen were investigated using scanning electron microscopy. Drill hole profiles were analyzed using profile projector and machine vision inspection system. An improvement in strength and stiffness combined with high toughness was achieved by treating the fibers using 10% NaOH solution. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Effect of processing technique on the dispersion of carbon nanotubes within polypropylene carbon nanotube‐composites and its effect on their mechanical properties
Authors: Esawi Amal M.K. , Salem Hanadi G. , Hussein Hanady M. , Ramadan Adham R.
Published: March 2009

Carbon nanotube‐reinforced polymer composites are being investigated as promising new materials having enhanced physical and mechanical properties. With regards to mechanical behavior, the enhancements reported thus far by researchers are lower than the theoretical predictions. One of the key requirements to attaining enhanced behavior is a uniform dispersion of the nanotubes within the polymer matrix. Although solvent mixing has been used extensively, there are concerns that any remaining solvent within the composite may degrade its mechanical properties. In this work, a comparison is carried out between solvent and “solvent‐free” dry mixing for dispersing multiwall carbon nanotubes in polypropylene before further melt mixing by extrusion. Various weight fractions of carbon nanotubes (CNTs) are added to the polymer and their effect on the mechanical properties of the resulting composites is investigated. Enhancements in yield strength, hardness, and Young's modulus when compared with the neat polymer, processed under similar conditions, are observed. Differences in mechanical properties and strain as a function of the processing technique (solvent or dry) are also clearly noted. In addition, different trends of enhancement of mechanical properties for the solvent and dry‐mixed extrudates are observed. Dry mixing produces composites with the highest yield strength, hardness, and modulus at 0.5 wt% CNT, whereas solvent mixing produces the highest mechanical properties at CNT contents of 1 wt%. It is believed that this difference is primarily dependent on the dispersion of CNTs within the polymer matrix which is influenced by the processing technique. Field emission scanning electron microscopy analysis shows the presence of clusters in large wt% CNT samples produced by dry mixing. Samples produced by solvent mixing are found to contain homogeneously distributed CNTs at all CNT wt fractions. CNT pull‐out is observed and may explain the limited enhancement in mechanical properties. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Electropolymerization of poly(methyl pyrrole)/carbon nanotubes composites derived from ionic liquid
Authors: Ahmad Shahzada
Published: March 2009

The use of conjugated polymer in electronics devices is believed to be the driving force for the tremendous R & D activity involving these materials. In this study, electropolymerization of N‐methyl pyrrole/carbon nanotubes composites has been performed galvanostatically in ionic liquid medium. A well‐ordered polymer composites of poly(methylpyrrole)/carbon nanotubes (pMPy/CNTs) nanostructures has been observed as revealed by atomic force microscopy. The current vs. voltage curves demonstrates an ohmic nature of the synthesized polymers. pMPy/CNT films are found more conductive than the pMPy films. It is believed that, this route can be further fined to other organic conjugated systems and, thus, opens an avenue for application for a host of polymers in electronic devices. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers