bluuebunny/crossref_metadata_2025_split huggingface dataset:
On neighborhoods of analytic functions with positive real part
Authors: Sokó Janusz 
Published: May 2011

AbstractLet h(z) = z + a2z2 + ⋅⋅⋅ be analytic in the unit disc \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}${\cal U}$\end{document} on the complex plane \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\mathbf {C}$\end{document}. For given κ < 1, \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\zeta \in \mathbf {C}$\end{document}, ℜζ > κ, we prove that if ζh′(z) ∈ Ω(κ, ζ) for all \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$z\in {\cal U}$\end{document}, then ℜ[ζh(z)/z] > κ for all \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$z\in {\cal U}$\end{document}, where \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\Omega (\kappa ,\zeta )=\lbrace w\in {\mathbf {C}}:|w-2\kappa +\overline{\zeta }|>|\Re w -\kappa |\rbrace$\end{document} is a concave domain with boundary being a parabola. Next we consider the classes of analytic functions \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}${{\cal P}(\alpha )}=\lbrace p:p(0)=1,\Re [p(z)\alpha \rbrace$\end{document} and \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}${\cal {P^{\prime }}}(\alpha )=\left\lbrace p:p(0)=1,\ [zp(z)]^{\prime }\in \Omega (\alpha ,1)\right\rbrace$\end{document}. For \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$q\in \cal {P^{\prime }}(\alpha )$\end{document} we find a sufficient condition on δ that implies the existence of a δ ‐neighborhood \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\widehat{N}_\delta (q)$\end{document} being contained in \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}${\cal P}(\beta )$\end{document}, where β ⩽ α < 1. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Lower extremity free flap reconstruction outcomes using venous coupler
Authors: Ducic Ivica , Brown Benjamin J. , Rao Samir S. 
Published: May 2011

AbstractBackground: Microvascular anastomotic coupling devices have been available to microsurgeons for over 20 years. Many studies have validated the efficacy of these devices for venous anastomosis. To date, there have been no large reports of their success in the anatomical region with the highest free flap failure rate, the lower extremity. Methods: A retrospective review of 67 consecutive patients who underwent lower extremity microvascular reconstruction performed from August 2003 to September 2010 was performed. Patient charts were reviewed for age, sex, medical comorbidities, etiology of defect, location of defect, flap type, anastomotic technique, complications, flap survival, and limb salvage outcome. Results: No patients returned to the operating room to have an arterial or venous anastomosis revised. Despite 100% vascular anastomosis patency rates in 67 consecutive lower extremity free flaps, flap survival rate was 95.5%. Total complication rate (13.4%) was due to two partial and one complete flap loss, three infections, two skin graft loses, and one hematoma. There were no intraoperative or perioperative complications involving the use of a microvascular anastomotic coupling device itself. Thirty‐day and long term limb salvage rate was 97% and 92.5%, respectively. Conclusion: Microvascular anastomotic coupling devices create effective venous anastomoses in lower extremity microvascular reconstruction. Thus, it presents an important tool in the armamentarium for lower extremity microsurgical reconstruction. © 2011 Wiley‐Liss, Inc. Microsurgery 2011.
Mesh epineurial splinting for late median nerve repair in older patients: A preliminary report
Authors: Bertelli Jayme Augusto , Kechele Paulo Roberto , Ghizoni Marcos Flávio , Fröde Tânia S. 
Published: May 2011

AbstractEleven patients over 40 years old, with median nerve lesions at the wrist, were operated on an average of 5 months after their injury. In six patients, the median nerve was repaired using a polypropylene mesh applied to secure the nerve stumps in contact, thereby allowing for direct repair with microsutures. Six patients had their median nerve repaired with sural grafts. The average gap length was 2.8 cm for the mesh repair, whereas it was 3.7 cm for the graft repair group. Eighteen months after surgery, pressure thresholds were perceived in the index and thumb pulp by all six patients with a mesh repair but in only two of five patients with a graft repair. Five in the mesh repair group recovered function in the abductor pollicis brevis muscle, versus none in the graft group. These preliminary results suggest that, in older patients, the use of a mesh to splint the coaptation site followed by direct nerve repair yields better recovery than conventional sural grafts. © 2011 Wiley‐Liss, Inc. Microsurgery 2011.
Free tissue transfer in reconstruction following soft tissue sarcoma resection
Authors: Penna Vincenzo , Iblher Niklas , Momeni Arash , Stark G. Björn , Bannasch Holger 
Published: May 2011

AbstractBackground: Radical surgical resection remains the single‐most important treatment in the curative multimodal therapy of soft tissue sarcomas. Refinements in surgical techniques have resulted in the development of function preserving approaches increasingly avoiding limb amputation. Patients and methods: The records of all patients (n = 34) who underwent microsurgical soft tissue coverage subsequent to primary resection of soft tissue sarcoma of the upper or lower limb from 1999 to 2009 are reviewed regarding postoperative complications, time until start of adjuvant radiation and functional outcome (Toronto Extremity Salvage Score, TESS). Results: Thirty‐four patients (range: 21–86 years) received a total of 35 free flaps. Complete tumor resection was obtained in 33 patients, one patient required re‐excision ultimately resulting in tumor‐free margin status (R0 resection). Major complications were encountered in four cases including one patient with complete flap loss requiring an additional free flap and three patients with partial flap loss requiring split‐thickness skin graft procedures. Minor complications were observed in three patients (9%). Extremity salvage could be achieved in 33 patients with adequate postoperative ambulation (TESS 84 ± 18) and adequate use of the upper extremity (TESS 80 ± 22). One patient underwent amputation. Mean time until start of adjuvant radiotherapy was 37 days (range 24–56 days). Conclusion: A synergetic center‐based interdisciplinary approach is crucial in therapeutical management of soft tissue sarcomas with the aim of R0 resection status and limb preservation. Plastic surgery contributes by offering microsurgical reconstruction using free tissue transfer, thus broadening surgical possibilities. This increases the chance of both adequate oncosurgical resection and limb preservation. © 2011 Wiley‐Liss, Inc. Microsurgery 2011.
Intravenous heparin use in digital replantation and revascularization: The Quebec provincial replantation program experience
Authors: Nikolis Andreas , Tahiri Youssef , St‐Supery Veronique , Harris Patrick G. , Landes Genevieve , Lessard Lucie , Sampalis John 
Published: May 2011

AbstractBackground: No consensus exists among microsurgeons regarding the role of intravenous (IV) heparin in digital replantation/revascularization. The current experience of the Provincial Replantation Center in Quebec was reviewed over a 4‐year period. Methods: An initial retrospective review of all revascularized or reimplanted digits at our Replantation Center from April 2004 to April 2006 was conducted. Then, data of all patients treated at our center from January 08 to September 08 were prospectively collected. The two cohorts were compared with regards to demographics, injury characteristics, postoperative thromboprophylaxis medication as well as complication and success rates. Proportions were compared using χ2 tests/Fisher's exact tests. Multivariate analysis was conducted with logistic regression. Results: 175 digits were treated from April 2004 to April 2006, including 104 revascularizations and 71 amputations. IV heparin was used in 35.1% of the cases and was associated with a 3.59‐fold (95% CI, 1.55–8.31) increase risk of developing a complication compared with cases where heparin was not used (P = 0.001). In 2008, 106 digits were treated. IV heparin was used in 14.6% of the cases and was not significantly associated with a higher complication rate compared with cases where heparin was not used (P = 0.612). Both cohorts' success rates were very similar (P = 0.557). The number of complications decreased from the first period (20.5%) to the second one (12.8%). Conclusion: Routine use of IV heparin following digital replantation and revascularization is not warranted. Surgical technique and type of injury remains the most important predictors for success in these complex procedures. © 2011 Wiley‐Liss, Inc. Microsurgery 2011.
Changes in arterial blood flow of free flaps after the administration of sildenafil in swine
Authors: Gravvanis Andreas , Papalois Apostolos , Delikonstantinou Iraklis , Pentilas Nicolaos , Zogogiannis Ioannis , Tsoutsos Dimosthenis , Karakitsos Dimitrios 
Published: May 2011

AbstractWe evaluated blood flow changes after experimental free tissue transfer and the potential hemodynamic effect of sildenafil on the free flap. Sixteen swine were used for free transfer of a latissimus dorsi myocutaneous flap to the chest that was anastomosed to the internal mammary vessels, and were randomized into controls and study group. The latter received a single dose of sildenafil, 6 hours following flap revascularization. Doppler ultrasonography revealed that arterial flow was mainly systolic postoperatively. Diastolic flow patterns were gradually restored after the first postoperative day. Pulsatility index (PI) significantly increased and flow volume decreased in all animals postoperatively. In the sildenafil group, PI significantly decreased and flow volume increased, while diastolic flow patterns were restored earlier on compared to controls, postoperatively. In conclusion, the administration of sildenafil after free tissue transfer increases flow volume and facilitates the restoration of diastolic blood flow patterns in the early critical postoperative period. © 2011 Wiley‐Liss, Inc. Microsurgery 2011.
Modeling of Look‐Locker estimates of the magnetic resonance imaging estimate of longitudinal relaxation rate in tissue after contrast administration
Authors: Paudyal Ramesh , Bagher‐Ebadian Hassan , Nagaraja Tavarekere N. , Fenstermacher Joseph D. , Ewing James. R. 
Published: May 2011

AbstractThis paper models the behavior of the longitudinal relaxation rate of the protons of tissue water R1 (R1 = 1/T1), measured in a Look‐Locker experiment at 7 Tesla after administration of a paramagnetic contrast agent (CA). It solves the Bloch‐McConnell equations for the longitudinal magnetization of the protons of water in a three‐site two‐exchange (3S2X) model with boundary conditions appropriate to repeated sampling of magnetization. The extent to which equilibrium intercompartmental water exchange kinetics affect monoexponential estimates of R1 after administration of a CA in dynamic contrast enhanced experiment is described. The relation between R1 and tissue CA concentration was calculated for CA restricted to the intravascular, or to the intravascular and extracellular compartments, by varying model parameters to mimic experimental data acquired in a rat model of cerebral tumor. The model described a nearly linear relationship between R1 and tissue concentration of CA, but demonstrated that the apparent longitudinal relaxivity of CA depends upon tissue type. The practical consequence of this finding is that the extended Patlak plot linearizes the ΔR1 data in tissue with leaky microvessels, accurately determines the influx rate of the CA across these microvessels, but underestimates the volume of intravascular blood water. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Design of a radiative surface coil array element at 7 T: The single‐side adapted dipole antenna
Authors: Raaijmakers A. J. E. , Ipek O. , Klomp D. W. J. , Possanzini C. , Harvey P. R. , Lagendijk J. J. W. , van den Berg C. A. T. 
Published: May 2011

AbstractUltra high field MR imaging (≥7 T) of deeply located targets in the body is facing some radiofrequency‐field related challenges: interference patterns, reduced penetration depth, and higher Specific Absorbtion Ratio (SAR) levels. These can be alleviated by redesigning the elements of the transmit or transceive array. This is because at these high excitation field (B1) frequencies, conventional array element designs may have become suboptimal. In this work, an alternative design approach is presented, regarding coil array elements as antennas. Following this approach, the Poynting vector of the element should be oriented towards the imaging target region. The single‐side adapted dipole antenna is a novel design that fulfills this requirement. The performance of this design as a transmit coil array element has been characterized by comparison with three other, more conventional designs using finite difference time domain (FDTD) simulations and B measurements on a phantom. Results show that the B level at the deeper regions is higher while maintaining relatively low SAR levels. Also, the B field distribution is more symmetrical and more uniform, promising better image homogeneity. Eight radiative antennas have been combined into a belt‐like surface array for prostate imaging. T1‐weighted (T1W) and T2‐weighted (T2W) volunteer images are presented along with B measurements to demonstrate the improved efficiency. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Quantitative myocardial perfusion imaging with a MR cold pressor test
Authors: Ritter C.O. , Kowalski M. , Weng A. M. , Beer M. , Hahn D. , Köstler H. 
Published: May 2011

AbstractThe response of myocardial blood flow to sympathetic stimulation with cold is modulated by endothelium‐related factors. As endothelial dysfunction is an early step in patients with coronary artery disease, the aim of this study was to establish a cold pressor test (CPT) setting for quantitative analysis of myocardial perfusion in a MR scanner. First pass perfusion studies were performed in 10 healthy volunteers using a 1.5 T MR scanner with a multislice steady state free precession perfusion trueFISP sequence in prebolus technique (1 cc/4 cc gadobenate dimeglumine). MR‐CPT was established using an over head ice‐water bath of the left hand. First pass perfusion imaging was started after 1 min to assure an adequate stimulus followed by a second series after 15 min to evaluate the rest perfusion. After motion correction images were segmented with an adapted, automated tool, myocardial contours were determined. Perfusion was quantitatively evaluated after contamination and baseline correction by deconvolution with the arterial input function using an exponential function model as residuum. All data could be evaluated. Mean myocardial perfusion rose from 0.61 ± 0.22 cc/g/min at rest to 1.15 ± 0.34 cc/g/min under CPT. MR myocardial perfusion values show a comparable increase under CPT as published positron emission tomography data. Consequently, CPT for the presence of endothelial dysfunction is feasible in the MR environment. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
MRI of frozen tissue demonstrates a phase shift
Authors: Lu Aiming , Daniel Bruce L. , Kaye Elena , Butts Pauly Kim 
Published: May 2011

AbstractWhile temperature mapping is desired during cryosurgery for prostate cancer treatment, an effective approach for this purpose is still needed. We have demonstrated a phase shift with temperature in our in vivo canine experiments and ex vivo tissue sample experiments within the frozen tissue. The phase shift is much larger (∼0.7 °/°C with an echo time of 0.1 ms at 0.5 T) in magnitude than that predicted by conventional proton resonant frequency shift (0.008 °/°C). It shows little dependence on the echo times used and thus is not due to a frequency change, although frequency‐dependent phase shift has been observed near the frozen tissue. This phase shift varies monotonically with temperature within the frozen tissue and therefore may be potentially used as a novel temperature mapping approach in cryoablation applications. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Nonexponential T2* decay in white matter
Authors: van Gelderen Peter , de Zwart Jacco A. , Lee Jongho , Sati Pascal , Reich Daniel S. , Duyn Jeff H. 
Published: May 2011

AbstractVisualizing myelin in human brain may help the study of diseases such as multiple sclerosis. Previous studies based on T1 and T2 relaxation contrast have suggested the presence of a distinct water pool that may report directly on local myelin content. Recent work indicates that T2* contrast may offer particular advantages over T1 and T2 contrast, especially at high field. However, the complex mechanism underlying T2* relaxation may render interpretation difficult. To address this issue, T2* relaxation behavior in human brain was studied at 3 and 7 T. Multiple gradient echoes covering most of the decay curve were analyzed for deviations from mono‐exponential behavior. The data confirm the previous finding of a distinct rapidly relaxing signal component (T2* ∼ 6 ms), tentatively attributed to myelin water. However, in extension to previous findings, this rapidly relaxing component displayed a substantial resonance frequency shift, reaching 36 Hz in the corpus callosum at 7 T. The component's fractional amplitude and frequency shift appeared to depend on both field strength and fiber orientation, consistent with a mechanism originating from magnetic susceptibility effects. The findings suggest that T2* contrast at high field may be uniquely sensitive to tissue myelin content and that proper interpretation will require modeling of susceptibility‐induced resonance frequency shifts. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
A symmetric mixed finite element method for nearly incompressible elasticity based on biorthogonal systems
Authors: Lamichhane Bishnu P. , Stephan Ernst P. 
Published: May 2011

AbstractWe present a symmetric version of the nonsymmetric mixed finite element method presented in (Lamichhane, ANZIAM J 50 (2008), C324–C338) for nearly incompressible elasticity. The displacement–pressure formulation of linear elasticity is discretized using a Petrov–Galerkin discretization for the pressure equation in (Lamichhane, ANZIAM J 50 (2008), C324–C338) leading to a non‐symmetric saddle point problem. A new three‐field formulation is introduced to obtain a symmetric saddle point problem which allows us to use a biorthogonal system. Working with a biorthogonal system, we can statically condense out all auxiliary variables from the saddle point problem arriving at a symmetric and positive‐definite system based only on the displacement. We also derive a residual based error estimator for the mixed formulation of the problem. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2012
The impact of no Child Left Behind on student achievement
Authors: Dee Thomas S. , Jacob Brian 
Published: May 2011

AbstractThe No Child Left Behind (NCLB) Act compelled states to design school accountability systems based on annual student assessments. The effect of this federal legislation on the distribution of student achievement is a highly controversial but centrally important question. This study presents evidence on whether NCLB has influenced student achievement based on an analysis of state‐level panel data on student test scores from the National Assessment of Educational Progress (NAEP). The impact of NCLB is identified using a comparative interrupted time series analysis that relies on comparisons of the test‐score changes across states that already had school accountability policies in place prior to NCLB and those that did not. Our results indicate that NCLB generated statistically significant increases in the average math performance of fourth graders (effect size 5 0.23 by 2007) as well as improvements at the lower and top percentiles. There is also evidence of improvements in eighth‐grade math achievement, particularly among traditionally low‐achieving groups and at the lower percentiles. However, we find no evidence that NCLB increased fourth‐grade reading achievement. © 2011 by the Association for Public Policy Analysis and Management.
Physical properties of lignin‐based polypropylene blends
Authors: Chen Feng , Dai Honghu , Dong Xiaoli , Yang Jintao , Zhong Mingqiang 
Published: May 2011

AbstractThe alkylation of kraft lignin with bromododecane was carried out to improve the compatibility with polypropylene (PP). The feasibility of PP/alkylated lignin composite was studied. It was found that the lignin could serve as fire retardant and toughening agent for PP matrix. Moreover, the higher lignin portion of the composites exhibited obvious damping effect. Although scanning electron micrographic observations indicated that PP‐lignin adhesion was improved by the alkylation, additional benefits were only obtained from impact behavior. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Effect of the resin/hardener ratio on curing, structure and glass transition temperature of nanofilled epoxies
Authors: Bignotti Fabio , Pandini Stefano , Baldi Francesco , De Santis Riccardo 
Published: May 2011

AbstractThe curing reaction, structure, and glass transition behavior of epoxy‐clay nanocomposites prepared using several different resin/hardener ratios were investigated. Nonisothermal DSC experiments evidenced that the incorporation of the organoclay did not induce appreciable changes in the curing enthalpy, but determined a slight acceleration of the curing reaction, without modifying the activation energy. TEM and SEM analyses of the nanocomposite resins showed the presence of micrometric aggregates for all the resin/hardener ratios investigated, even though these materials showed good optical clarity and their WAXD analyses did not evidence any organoclay peak. In addition, the higher the hardener content, the lower the tendency toward exfoliation and the broader the distribution of the interlamellar distances. The degree of cross‐linking of cured resins was evaluated both from measurements of the elastic modulus in the rubbery plateau and from solvent sorption experiments. A maximum in cross‐link density was observed near the stoichiometric composition. Both modulus and sorption experiments suggested that filler‐matrix adhesion increased with increasing the resin/hardener ratio, a trend that was confirmed also by glass transition temperature data. An analysis of ethyl acetate sorption curves evidenced that a gradual transition from Fickian to Case II diffusion occurred as the resin/hardener ratio was raised and that the organoclay promoted deviation from the Fickian behavior. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers