bluuebunny/crossref_metadata_2025 huggingface dataset:
Stenosis detection in forearm hemodialysis arteriovenous fistulae by multiphase contrast‐enhanced magnetic resonance angiography: Preliminary experience
Authors: Planken R. Nils , Tordoir Jan H.M. , Dammers Ruben , de Haan Michiel W. , Oei T. Khiam , van der Sande Freek M. , van Engelshoven Jos M.A. , Leiner Tim
Published: December 2002

Purpose

To assess the feasibility and accuracy of multiphase contrast‐enhanced magnetic resonance angiography (CE‐MRA) in patients with dysfunctioning hemodialysis arteriovenous fistulae (AVF), using digital subtraction angiography (DSA) as the standard of reference.

Materials and Methods

Fifteen patients with dysfunctioning AVF (eight radiocephalic and seven graft AVF) underwent CE‐MRA. Dysfunction was defined as a flow decline of more than 25% in 1 month measured by dilutional flow measurements. CE‐MRA was performed during injection of 35 mL of gadolinium‐DTPA. The CE‐MRA sequence consisted of a time‐resolved series of 10 scans, each lasting approximately 10 seconds. The technical parameters were TR/TE/FA/voxel = 5.4/1.6/40/3.1 mm3, and a rectangular surface reception coil was used. All patients were scheduled to undergo DSA at which an intervention was carried out when a stenosis ≥50% was seen. Two observers, unaware of each other's findings and the findings at DSA, quantified the number and degree of stenosis in the failing AVF. Image quality for CE‐MRA and DSA was scored on a 3‐point scale. The diagnostic performance of CE‐MRA was analyzed with receiver‐operator characteristic (ROC) analysis.

Results

CE‐MRA and DSA examinations were performed without side effects in all 15 patients. Image quality was scored significantly better on CE‐MRA (observer 1: CE‐MRA, 2.0; DSA, 1.3; P =.001; observer 2: CE‐MRA, 2.0; DSA, 1.4; P =.002). Interobserver agreement for detection of ≥50% stenosis was 0.81 (95% confidence interval (CI) = 0.71–0.92) for CE‐MRA and 0.69 (95% CI = 0.55–0.84) for DSA. ROC analysis revealed a mean area under the curve of 0.78. On the patient level, at the ≥50% threshold, mean sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 100% (95% CI = 69%–100%), 10% (95% CI = 0%–78%), 70% (95% CI = 38%–92%), and 100% (95% CI = 50%–100%), respectively. At the ≥75% threshold, mean sensitivity, specificity, PPV, and NPV were 75% (95% CI = 20%–99%), 78% (95% CI = 39%–98%), 55% (95% CI = 12%–96%), and 89% (95% CI = 52%–100%), respectively.

Conclusion

CE‐MRA is a useful diagnostic tool for detecting stenoses in flow‐declined hemodialysis AVF prior to interventional DSA. J. Magn. Reson. Imaging 2003;17:54–64. © 2002 Wiley‐Liss, Inc.
In vivo assessment of absolute perfusion in the murine skeletal muscle with spin labeling MRI
Authors: Streif Jörg U.G. , Hiller Karl‐Heinz , Waller Christiane , Nahrendorf Matthias , Wiesmann Frank , Bauer Wolfgang R. , Rommel Eberhard , Haase Axel
Published: December 2002

Purpose

To assess absolute perfusion in the skeletal muscle of mice in vivo with spin labeling magnetic resonance imaging (MRI) under normal and stress conditions.

Materials and Methods

Absolute perfusion in the skeletal muscle of 27 C57BL/6 mice was assessed in vivo non‐invasively by spin labeling MRI at 7.05 T. This technique was based on the acquisition of T1 maps with global and slice‐selective spin inversion in separate acquisitions. T1 mapping was performed by inversion recovery snapshot fast low angle shot imaging. To guarantee proper spin inversion within the whole mouse, a dedicated radiofrequency (RF) coil combination was constructed. A birdcage resonator was used for transmission, while detection of the MRI signal was achieved by a surface coil.

Results

Basal perfusion in the hindlimbs was determined to be 94 ± 10 mL (100 g · minute)–1 (mean ± standard error of the mean [SEM], N = 27). This value is in good agreement with perfusion values determined by invasive techniques such as microspheres. A subgroup of six animals received a constant dose of 4 mg (kg · minute)–1 of the vasodilator adenosine by an intraperitoneal catheter. In this case, perfusion was significantly increased to 179 ± 56 mL (100 g · minute)–1 (mean ± SEM, N = 6, P < 0.02). Mean basal perfusion in this subgroup was 96 ± 26 mL (100 g · minute)–1.

Conclusion

Spin labeling MRI is a well‐suited technique for the in vivo assessment of absolute perfusion in the murine skeletal muscle. J. Magn. Reson. Imaging 2003;17:147–152. © 2002 Wiley‐Liss, Inc.
Initial in vivo experience with steady‐state subzone‐based MR elastography of the human breast
Authors: Van Houten Elijah E.W. , Doyley Marvin M. , Kennedy Francis E. , Weaver John B. , Paulsen Keith D.
Published: December 2002

Purpose

To describe initial in vivo experiences with a subzone‐based, steady‐state MR elastography (MRE) method. This sparse collection of in vivo results is intended to shed light on some of the strengths and weaknesses of existing clinical MRE approaches and to indicate important areas of future research.

Materials and Methods

Elastic property reconstruction results are compared with data compiled from the limited existing body of published studies in breast elasticity. Mechanical parameter distributions are also investigated in terms of their implications for the nature of biological soft tissue. Additionally, a derivation of the statistical variance of the elastic parameter reconstruction is given and the resulting confidence intervals (CIs) for different parameter solutions are examined.

Results

By comparison with existing estimates of the elastic properties of breast tissue, the subzone‐based, steady‐state MRE method is seen to produce reasonable estimates for the mechanical properties of in vivo tissue.

Conclusion

MRE shows potential as an effective way to determine the elastic properties of breast tissue, and may be of significant clinical interest. J. Magn. Reson. Imaging 2003;17:72–85. © 2002 Wiley‐Liss, Inc.
Kinetics and mechanism of oxidation of antimony(III) by keggin‐type 12‐tungstocobaltate(III) in aqueous hydrochloric acid medium
Authors: Bhosale B. D. , Gokavi G. S.
Published: December 2002

The reaction between Sb(III) and [CoIIIW12O40]5− proceeds with two, one‐electron steps; formation of unstable Sb(IV) is the slow first step followed by its reaction with another oxidant in a fast step. The reaction rate is unaffected by the [H+] as there are no protonation equlibria involved with both the reactants, whereas the accelerating effect of chloride ion is due to the formation of an active chlorocomplex of the reductant, SbCl63−. Increase in the ionic strength and decrease in the relative permittivity of the medium increases the rate of the reaction, which is attributed to the formation of an outer‐sphere complex between the reactants. The activation parameters were also determined and these values support the proposed mechanism. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 9–14, 2003
Kinetic evidence of a common mechanism in the oxidations of diethyl sulfide by dichromates and halochromates of heterocyclic bases
Authors: Karunakaran C. , Karuthapandian S. , Suresh S.
Published: December 2002

The oxidations of diethyl sulfide by potassium dichromate, pyridinium dichromate, quinolinium dichromate, imidazolium dichromate, nicotinium dichromate, isonicotinium dichromate, pyridinium fluorochromate, quinolinium fluorochromate, imidazolium fluorochromate, pyridinium chlorochromate, quinolinium chlorochromate, and pyridinium bromochromate follow identical kinetic orders—first‐order each with respect to the chromium(VI) reagents, sulfide and hydrogen ion, and moderately inhibited by manganese(II) ion. The energy of activation varies linearly with the logarithm of frequency factor and so does the enthalpy of activation with the entropy of activation. Also, the activation free energies do not differ significantly. The dichromates and halochromates of heterocyclic bases oxidize diethyl sulfide via a common mechanism. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 1–8, 2003
Reaction of H + ketene to formyl methyl and acetyl radicals and reverse dissociations
Authors: Lee Jongwoo , Bozzelli Joseph W.
Published: December 2002

Thermochemical properties for reactants, intermediates, products, and transition states important in the ketene (CH2CO) + H reaction system and unimolecular reactions of the stabilized formyl methyl (C·H2CHO) and the acetyl radicals (CH3C·O) were analyzed with density functional and ab initio calculations. Enthalpies of formation (ΔHf°298) were determined using isodesmic reaction analysis at the CBS‐QCI/APNO and the CBSQ levels. Entropies (S°298) and heat capacities (Cp°(T)) were determined using geometric parameters and vibrational frequencies obtained at the HF/6‐311G(d,p) level of theory. Internal rotor contributions were included in the S and Cp(T) values. A hydrogen atom can add to the CH2‐group of the ketene to form the acetyl radical, CH3C·O (Ea = 2.49 in CBS‐QCI/APNO, units: kcal/mol). The acetyl radical can undergo β‐scission back to reactants, CH2CO + H (Ea = 45.97), isomerize via hydrogen shift (Ea = 46.35) to form the slight higher energy, formyl methyl radical, C·H2CHO, or decompose to CH3 + CO (Ea = 17.33). The hydrogen atom also can add to the carbonyl group to form C·H2CHO (Ea = 6.72). This formyl methyl radical can undergo β scission back to reactants, CH2CO + H (Ea = 43.85), or isomerize via hydrogen shift (Ea = 40.00) to form the acetyl radical isomer, CH3C·O, which can decompose to CH3 + CO. Rate constants are estimated as function of pressure and temperature, using quantum Rice–Ramsperger–Kassel analysis for k(E) and the master equation for falloff. Important reaction products are CH3 + CO via decomposition at both high and low temperatures. A transition state for direct abstraction of hydrogen atom on CH2CO by H to form, ketenyl radical plus H2 is identified with a barrier of 12.27, at the CBS‐QCI/APNO level. ΔHf°298 values are estimated for the following compounds at the CBS‐QCI/APNO level: CH3C·O (−3.27), C·H2CHO (3.08), CH2CO (−11.89), HC·CO (41.98) (kcal/mol). © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 20–44, 2003
Estimation of rate constants for hydrogen atom abstraction by OH radicals using the CH bond dissociation enthalpies: Haloalkanes and haloethers
Authors: Chandra Asit K. , Uchimaru Tadafumi , Urata Shingo , Sugie Masaaki , Sekiya Akira
Published: December 2002

We propose a semiempirical procedure for the estimation of the rate constants for hydrogen atom abstraction reactions of OH radicals with haloalkanes and haloethers. Our procedure is derived from the collision theory based kinetic equation, which was originally proposed by Heicklen (Int. J. Chem. Kinet. 1981, 13, 651). This equation provides the estimates for the rate constants of hydrogen abstraction from the CH bond dissociation enthalpy for each potential hydrogen atom abstraction site. We reparameterized the equation and then applied this procedure to a series of haloalkane and haloether molecules. The results obtained from the new equations are found to be quite satisfactory. In addition, we also report highly reliable calculated values of the CH bond dissociation enthalpies for six environmentally important haloether molecules (CH2FOCH2F, CHF2CF2OCH2CF3, CF3CH2OCH2CF3, CF3CF2CH2OCHF2, CHF2OCF2CHFCl, and CHF2OCHClCF3). © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 130–138, 2003
Kinetics of the gas‐phase reaction of n‐C6–C10 aldehydes with the nitrate radical
Authors: Noda Jun , Holm Camilla , Nyman Gunnar , Langer Sarka , Ljungström Evert
Published: December 2002

Rate coefficients for gas‐phase reaction between nitrate radicals and the n‐C6–C10 aldehydes have been determined by a relative rate technique. All experiments were carried out at 297 ± 2 K, 1020 ± 10 mbar and using synthetic air or nitrogen as the bath gas. The experiments were made with a collapsible sampling bag as reaction chamber, employing solid‐phase micro extraction for sampling and gas chromatography/flame ionization detection for analysis of the reaction mixtures. One limited set of experiments was carried out using a glass reactor and long‐path FTIR spectroscopy. The results show good agreement between the different techniques and conditions employed as well as with previous studies (where available). With butanal as reference compound, the determined values (in units of 10−14 cm3 molecule−1 s−1) for each of the aldehydes were as follows: hexanal, 1.7 ± 0.1; heptanal, 2.1 ± 0.3; octanal, 1.5 ± 0.2; nonanal, 1.8 ± 0.2; and decanal, 2.2 ± 0.4. With propene as reference compound, the determined rate coefficients were as follows: heptanal, 1.9 ± 0.2; octanal, 2.0 ± 0.3; and nonanal, 2.2 ± 0.3. With 1‐butene as reference compound, the rate coefficients for hexanal and heptanal were 1.6 ± 0.2 and 1.8 ± 0.1, respectively. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 120–129, 2003
Ethical ideologies: Efficient assessment and influence on ethical judgments of marketing practices
Authors: Kleiser Susan Bardi , Sivadas Eugene , Kellaris James J. , Dahlstrom Robert F.
Published: December 2002

Individuals often differ with respect to their ethical judgments of marketing practices. Personal beliefs are presumably important sources of such differences. This article reports on the development and testing of an original, parsimonious measure of personal moral beliefs based on Forsyth's (1980) taxonomy of ethical ideologies. In contrast to Forsyth's longer, more general measure, the short scale presented here is designed specifically for application in marketing ethics research. Results of three studies suggest that Idealism and Ideological Relativism dimensions can be reliably distinguished and represented by the authors' 7‐item MEI (Marketing Ethical Ideology) scale. Moreover, ethical ideology is shown to influence evaluations of representative ethical problems in marketing. © 2003 Wiley Periodicals, Inc.
Effects of counterfactual thought on postpurchase consumer affect
Authors: Walchli Suzanne B. , Landman Janet
Published: December 2002

This study explored the effects of counterfactual thinking (CFT) on postpurchase consumer affect. CFT is the process of imagining what might have been, that is, comparing reality (what is; the facts) with alternative possibilities. In a vignette study, the presence or absence of CFT, its direction (upward or downward), and outcome valence (positive, negative, or neutral) were manipulated. The participants' tendencies toward strategic optimism and defensive pessimism were measured, and the impact of these factors on postpurchase affect was observed. As expected, results indicated that negative outcomes were associated with greater levels of spontaneous counterfactual thought, and greater affective amplification was associated with the presence of counterfactual thought. More surprising was the finding that consumer regret increased with both downward and upward counterfactual thought, indicating that both contrast and assimilation mechanisms may be operational. With respect to personality, strategic optimists were less sensitive to purchase outcomes and counterfactual thought manipulations than were other respondents. © 2003 Wiley Periodicals, Inc.
Management of flaps with compromised venous outflow in head and neck microsurgical reconstruction
Authors: Kubo Tateki , Yano Kenji , Hosokawa Ko
Published: December 2002

Microvascular tissue transfer has become an indispensable procedure for head and neck reconstruction. Although remarkable progress has been made technically, anastomosed vessel occlusion is still a serious complication. Even with technically skilled microsurgeons, anastomosed vessel occlusion occurs because the technique is not the sole prophylaxis against thrombosis in microsurgery. Therefore, to minimize the possibility of an unfavorable result in microsurgery, microsurgeons must be familiar with management options for a vascular compromised flap. Most investigators have agreed that venous obstruction occurs more often than arterial obstruction. Here, we reviewed the published literature on the salvage of venous compromised flaps from the viewpoints of surgical correction, including reanastomosis and catheter thrombectomy, and nonsurgical procedures, such as a medicinal leech, hyperbaric oxygen, and thrombolytic therapy. © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:391–395 2002
Vein grafting with telescoping anastomoses for repair of a double‐cut artery
Authors: Hosaka Masato , Saitoh Satoru , Murakami Narumichi , Kobayashi Hirokazu , Hata Yukihiko , Ohira Masayoshi , Kimura Teiji
Published: December 2002

The rat femoral artery was cut in two places, and the telescoping anastomosis technique was used for all vascular repairs in combination with vein grafting, to determine whether the telescoping technique could safely be used more than three times for repair of an artery that has been injured at two places. One cut was repaired with vein grafting, and the other with either a telescoping anastomosis (the triple group) or with a second vein grafting (the quadruple group). The patency rate 3 weeks postoperatively was 86.4% for the triple group, and 90.5% for the quadruple group. Although tension of the repaired vessel was kept low by vein grafting, and deformities of the inserted vessel were carefully minimized, the patency rate was not 100%. It appears that a telescoping anastomosis should not be used more than three times on the same artery in combination with vein grafting. © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:335–338 2002
Biochemical evaluation of serum and flexor tenosynovium in carpal tunnel syndrome
Authors: Freeland Alan E. , Tucci Michelle A. , Barbieri Rocco A. , Angel Michael F. , Nick Todd G.
Published: December 2002

In total, 41 consecutive patients with “idiopathic carpal tunnel syndrome” and abnormal electrophysiologic findings who underwent carpal tunnel release were studied prospectively. The focus of this investigation was the evaluation of the levels of specific chemical mediators within the serum and flexor tenosynovium of these patients. Blood was collected from these patients within 1 week prior to carpal tunnel release, and flexor tenosynovium was obtained at time of surgery. Specimens were then analyzed to determine the levels of interleukins 1 and 6, prostaglandin E2 (PGE2), and malondialdehyde bis diethyl acetal. These values were compared to those of controls who had no evidence of carpal tunnel syndrome. A significant increase was noted in the serum malondialdehyde and tenosynovial levels of malondialdehyde, interleukin 6, and prostaglandin PGE2 compared to controls. The elevated levels of these biologic factors and the absence of interleukin 1 elevation support a noninflammatory ischemia‐reperfusion etiology for so‐called “idiopathic carpal tunnel syndrome” that causes progressive edema and fibrosis of the tissues within the carpal canal. These findings correlate with previous histopathology reports. We believe that “idiopathic carpal tunnel syndrome” is an “‐osis” not an “‐itis.” © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:378–385 2002
Hypertrophy after free vascularized fibular transfer to the lower limb
Authors: El‐Gammal Tarek Abdalla , El‐Sayed AMR , Kotb Mohammed M.
Published: December 2002

This study included 25 patients with lower limb tumors who had reconstruction by vascularized fibula osteoseptocutaneous flap performed at least 24 months before the end of the study. Hypertrophy of the transplanted fibula was estimated on serial radiographs by a modification of the formula of De Boer and Wood (J Bone Joint Surg [Br] 71:374–378, 1989). A significant graft was observed in 90% of the patients at an average follow‐up of 27 months (range, 30–200%). The time to graft union (start of partial weight‐bearing) positively correlated with the time to significant graft hypertrophy (r = 0.9, P < 0.01). The final amount of graft hypertrophy was affected by the age of the patient (P < 0.01) and the length of follow‐up (P < 0.05). Graft hypertrophy progressed at an average rate of 3.3% per month (range, 2.3–4.9%) until the end of the 30th month; thereafter, little or no increase in graft hypertrophy was observed. The rate of graft hypertrophy showed two significant peaks at 6–12 months (P < 0.001) and at 18–24 months (P < 0.05). Patients younger than age 20 years showed faster hypertrophy, with a peak at the 12th month. Hypertrophy progressed faster in patients who received chemotherapy until the 12th month, and then declined sharply compared to those who did not receive chemotherapy. © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:367–370 2002
Effect of nondepleting anti‐CD4 monoclonal antibody (Rib 5/2) plus donor antigen pretreatment in peripheral nerve allotransplantation
Authors: Doolabh Vaishali B. , Tung Thomas H. , Wayne Flye M. , Mackinnon Susan E.
Published: December 2002

Peripheral nerve allotransplantation allows the reconstruction of injuries with long nerve gaps that are otherwise unsalvageable. In this study, the efficacy of anti‐CD4 monoclonal antibody (mAb) combined with donor antigen pretreatment in prolonging the survival of short peripheral nerve allografts was investigated in a rodent model. Such an approach could potentially avoid the need for systemic immunosuppression and its concomitant morbidities. Buffalo rats received either nerve isografts or nerve allografts from Lewis rats. Untreated isograft and allograft groups were used as controls. Allograft recipients received either a single dose of RIB 5/2, a nondepleting anti‐CD4 mAb, a single dose of Lewis splenocytes, or both antigen and RIB 5/2, 7 days prior to transplantation. Flow cytometric analysis verified that the T‐lymphocyte population was maintained, while CD4 expression was downregulated by RIB 5/2. Histologic evaluation demonstrated better regeneration in the allograft recipients receiving both donor antigen and antibody, compared to recipients of untreated allografts or treatment with antigen or antibody alone. © 2002 Wiley‐Liss, Inc. MICROSURGERY 22:329–334 2002
Traction injury of common peroneal nerve associated with multiple ligamentous rupture of the knee: A case report
Authors: Takagi Takehiko , Nakao Yasushi , Takayama Shinichiro , Toyama Yoshiaki
Published: December 2002

We report on a case of a 19‐year‐old male student who sustained a hyperextension injury to his left knee while playing rugby, which resulted in a traction injury of the common peroneal nerve and multiple ligamentous injuries at the knee joint. The damaged part of the common peroneal nerve was resected, and an end‐to‐end suture was performed, because the gap between the nerve ends was small enough to allow closure with little mobilization. Now, 2.5 years after the surgery, the patient shows remarkable recovery. This result suggests that end‐to‐end suture is an ideal procedure for nerve traction injury, if the nerve ends can be closed without tension, without excessive flexion of the adjacent joint.© 2002 Wiley‐Liss, Inc. MICROSURGERY 22:339–342 2002
Involvement of numb in vertebrate retinal development: Evidence for multiple roles of numb in neural differentiation and maturation
Authors: Dooley Constance M. , James Jackson , Jane McGlade C. , Ahmad Iqbal
Published: December 2002

Cell fate specification is regulated in part by lateral inhibition mediated by Notch signaling. Notch signaling is negatively regulated by Numb, an intrinsic factor that regulates cellular competence. In this study we have examined the involvement of Numb in retinal development, which has been shown to be influenced by Notch signaling. In the developing retina, Numb is asymmetrically distributed towards the ventricular and vitreal poles of different cells. Asymmetric localization is evident not only in mitotic cells but in postmitotic ganglion cells as well, suggesting that the subcellular distribution of Numb may play a role after cells have exited the cell cycle. This is supported by the expression of Numb in terminally differentiated neurons in the adult retina. Although Numb is an intrinsic factor, it is observed that its subcellular distribution is influenced by epigenetic cues such that a higher proportion of cells cultured at high density express Numb asymmetrically. A correlation is observed between asymmetric localization and cellular competence; cells in which Numb is asymmetric differentiate more readily in culture than those that express Numb symmetrically. We have identified alternative splice variants in the developing and adult retina that correspond to isoforms that have been shown to regulate proliferation and differentiation. The dynamic temporal expression patterns of alternative splice variants and isoforms suggest that Numb may influence proliferation and differentiation of retinal progenitors during neurogenesis and maturation of postmitotic neurons. Together, these results demonstrate the complex role of the distribution of Numb within progenitors and postmitotic neurons. © 2002 Wiley Periodicals, Inc. J Neurobiol 54: 313–325, 2003
Distribution of GluR1 is altered in the olfactory bulb following neonatal naris occlusion
Authors: Hamilton Kathryn A. , Coppola David M.
Published: December 2002

The olfactory system is well suited for studies of glutamate receptor plasticity. The sensory neurons are glutamatergic, and they turn over throughout life, and the olfactory bulb neurons that process their inputs express many of the known glutamate receptor subunits. Neonatal naris occlusion alters olfactory bulb development and the expression of certain neuroactive substances and receptors, at least in part due to loss of the sensory inputs. We therefore postulated that neonatal naris occlusion might alter glutamate receptor expression during postnatal development. Single nares of newborn mice were occluded on postnatal days 1–2, and the distribution of glutamate receptor subunits was evaluated using immunoperoxidase methods. Light microscopic examination on postnatal day 6 failed to reveal adult‐like staining of neuronal cell bodies in the olfactory bulbs. By day 12, cell bodies that were immunoreactive (‐IR) for the GluR1 subunit were visible in the external plexiform layer (EPL) of both sides. By day 18, many of the GluR1‐IR cell bodies could be identified as cell types that had previously been reported to express homomeric GluR1 receptors. Analysis of single, mid‐dorsal sections from 18–25‐day‐old mice showed that the medial EPL of the occluded side had a significantly lower density of these cell bodies. The GluR1 staining of the adjacent mitral cell layer (MCL) was also heavier on the occluded side, but no gross differences in staining for other glutamate receptor subunits were observed. Neonatal naris occlusion therefore appears to provide a new model for studying expression of GluR1 receptors during the development of a discrete population of olfactory bulb neurons. © 2002 Wiley Periodicals, Inc. J Neurobiol 54: 326–336, 2003
Using finite element tools in proving shift theorems for elliptic boundary value problems
Authors: Bacuta Constantin , H. Bramble James , E. Pasciak Joseph
Published: December 2002

We consider the Laplace equation under mixed boundary conditions on a polygonal domain Ω. Regularity estimates in terms of Sobolev norms of fractional order for this type of problem are proved. The analysis is based on new interpolation results and multilevel representation of norms on the Sobolev spaces Hα(Ω). The Fourier transform and the construction of extension operators to Sobolev spaces on ℝ2 are avoided in the proofs of the interpolation theorems. Copyright © 2002 John Wiley & Sons, Ltd.
On preconditioners for mortar discretization of elliptic problems
Authors: Dryja M. , Proskurowski W.
Published: December 2002

We consider elliptic problems with discontinuous coefficients defined on a union of two polygonal subdomains. The problems are discretized by the finite element method on non‐matching triangulation across the interface. The discrete problems are described by the mortar technique in the space with constraints (the mortar condition) and in the space without constraints using Lagrange multipliers. To solve the discrete problems Preconditioned conjugate gradient iterations are used with Neumann–Dirichlet and Neumann–Neumann preconditioners in the first case, and dual Neumann–Dirichlet and dual Neumann–Neumann (or FETI, the finite element tearing and interconnecting) in the second case. An analysis of convergence of all four of these preconditioners is given. Numerical comparison of their performance on non‐matching grids is presented. The general observation is that all preconditioners considered are very robust for the cases with the discontinuity ratio of 1000 across the interface. Copyright © 2002 John Wiley & Sons, Ltd.
A stabilized discontinuous finite element method for elliptic problems
Authors: Ewing Richard E. , Wang Junping , Yang Yongjun
Published: December 2002

A new finite element method is proposed and analysed for second order elliptic equations using discontinuous piecewise polynomials on a finite element partition consisting of general polygons. The new method is based on a stabilization of the well‐known primal hybrid formulation by using some least‐squares forms imposed on the boundary of each element. Two finite element schemes are presented. The first one is a non‐symmetric formulation and is absolutely stable in the sense that no parameter selection is necessary for the scheme to converge. The second one is a symmetric formulation, but is conditionally stable in that a parameter has to be selected in order to have an optimal order of convergence.

Optimal‐order error estimates in some H1‐equivalence norms are established for the proposed discontinuous finite element methods. For the symmetric formulation, an optimal‐order error estimate is also derived in the L2 norm. The new method features a finite element partition consisting of general polygons as opposed to triangles or quadrilaterals in the standard finite element Galerkin method. Copyright © 2002 John Wiley & Sons, Ltd.
Balancing domain decomposition for mortar mixed finite element methods
Authors: Pencheva Gergina , Yotov Ivan
Published: December 2002

The balancing domain decomposition method for mixed finite elements by Cowsar, Mandel, and Wheeler is extended to the case of mortar mixed finite elements on non‐matching multiblock grids. The algorithm involves an iterative solution of a mortar interface problem with one local Dirichlet solve and one local Neumann solve per subdomain on each iteration. A coarse solve is used to guarantee that the Neumann problems are consistent and to provide global exchange of information across subdomains. Quasi‐optimal condition number bounds are derived, which are independent of the jump in coefficients between subdomains. Numerical experiments confirm the theoretical results. Copyright © 2002 John Wiley & Sons, Ltd.
A multigrid method based on graph matching for convection–diffusion equations
Authors: Kim HwanHo , Xu Jinchao , Zikatanov Ludmil
Published: December 2002

In this paper we propose a practical and robust multigrid method for convection–diffusion problems based on a new coarsening techniques for unstructured grids. The idea is to use a graph matching technique to define proper coarse subspaces. Such an approach is based on the graph corresponding to the stiffness matrix, and is purely algebraic. We prove that our coarsening technique preserves the M matrix property. We also give several numerical examples illustrating the robustness of the method with respect to the variations in both the diffusion and convection coefficients. Copyright © 2002 John Wiley & Sons, Ltd.
Thermodynamic interaction parameter of star–star polybutadiene blends
Authors: Martter T. D. , Foster M. D. , Yoo T. , Xu S. , Lizarraga G. , Quirk R. P.
Published: December 2002

The value of the thermodynamic interaction parameter, χeff, for star–star polybutadiene blends was determined with small‐angle neutron scattering. Blends in which the stars have the same number of arms and blends in which the stars have different numbers of arms are investigated. For star–star isotopic blends with components having the same number of arms, the presence of the junction point of the star leads to a value of χeff that is larger than that for an analogous linear–linear isotopic blend. However, changes in the value of χeff resulting from small dissimilarities in the number of arms of the two components in the isotopic star–star blends were too small to resolve. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 247–257, 2003
Dynamic mechanical thermal analysis transitions of partially and fully substituted cellulose fatty esters
Authors: Vaca‐Garcia C. , Gozzelino G. , Glasser W. G. , Borredon M. E.
Published: December 2002

The main transitions of cellulose fatty esters with different degrees of substitution (DSs) were investigated with dynamic mechanical thermal analysis. Two distinct main relaxations were observed in partially substituted cellulose esters (PSCEs). They were attributed to the glass‐transition temperature and to the chain local motion of the aliphatic substituents. The temperatures of both transitions decreased when DS or the number of carbon atoms (n) of the acyl substituent increased. Conversely, all the transitions of fully substituted cellulose esters occurred within a narrow temperature range, and they did not vary significantly with n. This phenomenon was explained by the formation of a crystalline phase of the fatty substituents. The presence of few residual OH groups in PSCEs was responsible for a large increase in the storage bending modulus, and it eliminated the effect of n on damping. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 281–288, 2003
Large deformation of films from soft‐core/hard‐shell hydrophobic latices
Authors: Domingues Dos Santos Fabrice , Leibler Ludwik
Published: December 2002

Structured soft‐core/hard‐shell hydrophobic latices form rigid and transparent films under ambient conditions without the need of coalescing aids. The studied films have a composite structure, with the majority of soft poly(n‐butyl acrylate) dispersed in a continuous poly(methyl methacrylate) (PMMA) matrix. The matrix is formed by thin latex shells brought into intimate contact by surface forces. Despite the weakness of the interfaces between adjacent shells, the films exhibit high yield stress and surprising ductility. These properties result from a very specific PMMA matrix structure built from PMMA ligaments with a thickness of a few nanometers. Under these conditions, PMMA appears to shear without damage. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 224–234, 2003
Comparison of statistical and blocky copolymers of ethylene terephthalate and ethylene 4,4′‐bibenzoate based on thermal behavior and oxygen transport properties
Authors: Liu R. Y. F. , Hu Y. S. , Hibbs M. R. , Collard D. M. , Schiraldi D. A. , Hiltner A. , Baer E.
Published: December 2002

Poly(ethylene terephthalate) (PET) was blended with a frustrated liquid‐crystalline polymer, poly(ethylene terephthalate‐co‐4,4′‐bibenzoate) (PETBB55), in the weight ratio 70:30. Under the melt conditions used for blending, NMR analysis showed that some transesterification had occurred. Accordingly, the blended product resembled a blocky copolymer more closely than it did a physical blend. A random copolymer with the same composition was synthesized for comparison. The study examined the effect of the comonomer distribution (blocky vs random) on the thermal behavior and oxygen transport properties of the glassy and cold‐drawn polymers. The glass‐transition temperatures and the crystallization behavior suggested that the PETBB55 blocks phase‐separated as very small domains. Higher levels of orientation, as indicated by higher densities and higher trans glycol fractions, were achieved by the cold drawing of the blocky copolymer. It was speculated that the cold drawing of the blocky copolymer at temperatures up to the glass‐transition temperature of the PETBB55 blocks produced highly oriented PETBB55 domains. Constraints imposed by connections between PET and the PETBB55 blocks prevented the relaxation of the continuous PET phase, even at temperatures well above the glass‐transition temperature of the PET blocks. In this sense, the blocky copolymer embodied the concept of a self‐reinforcing polymer. As a result, an improved oxygen barrier was obtained over a wider range of cold‐draw temperatures with the blocky copolymer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 289–307, 2003
Constructing views of science tied to issues of equity and diversity: A study of beginning science teachers
Authors: Bianchini Julie A. , Solomon Eric M.
Published: December 2002

In this study, we examined the discursive and social practices of a teacher educator (the first author) and her eight beginning science teachers in a course on the nature of science and issues of equity and diversity. We focused our investigation on beginning science teachers' views of science and science teaching, as well as the grounds they offered for their views. We organized our discussion of the nature of science, teacher learning, and grounds for views along three dimensions: personal, social, and political. We found that beginning teachers routinely drew from only one of these three dimensions to support their views of the nature of science and ways to represent science to all students. In our implications, we recommend that teacher educators encourage teacher learners to examine personal, social, and political grounds carefully and critically in the process of constructing or revising their views. We argue that attention to these three dimensions of grounds for views will assist beginning teachers in adopting nature of science positions that are broad and complex, that more clearly reflect the goals of equity and excellence, and thus, that hold greater promise for achieving a science education inclusive of all students. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 53–76, 2003
Contrasting landscapes: A comparison of the impact of different induction programs on beginning secondary science teachers' practices, beliefs, and experiences
Authors: Luft Julie A. , Roehrig Gillian H. , Patterson Nancy C.
Published: December 2002

Induction programs are essential in addressing the unique pedagogical and content needs of secondary science teachers. Yet most secondary science teachers have little access to general induction programs, and even less opportunity to participate in specialized science induction programs. This study examines the impact of three different induction programs on secondary science teachers. The teachers were matched by grade level among three groups; one group participated in a science‐focused support program, another participated in a general support program, and a third had no formal support. All teachers were monitored during the spring semester to understand their teaching beliefs, instructional practices, and experiences in the classroom. The analysis of data revealed that the secondary science teachers in the science‐focused support program implemented more student‐centered inquiry lessons, held beliefs aligned with student‐centered practices, and felt fewer constraints in their teaching than did the other two groups of teachers. This study reinforces the importance of induction programs for teachers, suggests there is a need for specialized support programs for beginning science teachers, and recommends that universities and school districts work together to develop such programs. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 77–97, 2003
Software Radio—a key technology for adaptive access
Authors: Noll Josef , Buracchini Enrico
Published: December 2002

The paper provides a vision of an adaptive wireless access for next‐generation services. Depending on the requirements of the applications and the user situation, an optimum access method has to be selected. Software (SW) radio is the key enabling technology in this field. The functionality of a SW radio is described, and the challenges for future developments are identified. A major advantage of SW radio is the on‐the‐fly upgrade capabilities, both of terminals and of base stations. The paper concludes with a presentation of future trends, hybrid fibre distribution of radio signals and mechanisms for control of the various access networks. Copyright © 2002 John Wiley & Sons, Ltd.
A software radio–based reconfigurable transponder for space applications
Authors: Mondin Marina , Presti Letizia Lo , Scova Alessandro
Published: December 2002

A novel approach to space communications is represented by the Software Radio (SR) concept, a new technology currently deeply investigated by the scientific community, especially for wireless applications such as mobile communications or wireless network access. The SR approach leads to the definition of a new generation of radio equipment, whose communication functions are almost completely defined by means of software modules. The main outcome of the deployment of this technology is the great flexibility of the radio interface. As a matter of fact the communication standards can be easily reconfigured by simply replacing the corresponding software modules.

This paper describes the SDRsat research project that aims at designing a complete software radio reconfigurable regenerative transponder for space applications. Copyright © 2002 John Wiley & Sons, Ltd.
Sea surface salinity measurements in the historical database
Authors: Bingham Frederick M. , Howden Stephan D. , Koblinsky Chester J.
Published: December 2002

We have examined historical distributions of sea surface salinity (SSS) observations in a data set consisting of a combination of the World Ocean Database 1998 (WOD98) and a thermosalinograph and bucket salinity database collected from volunteer observing ships. It is well known that SSS in much of the world's ocean is measured infrequently or not at all. We find that 27% of one‐degree squares in the world ocean (open and coastal, excluding the Arctic Ocean) had no observations of SSS in the historical database, and 70% had 10 or fewer. Systematic sampling of SSS (more than 10,000 observations per year globally) did not start until after 1960. Most SSS observations in the WOD98 are concentrated in the North Sea and coast of northern Europe, the east and west coasts of North America, and around Japan. About 28% of SSS measurements are in coastal waters. We plotted frequency histograms of SSS for some selected well‐sampled one‐degree squares in the North Atlantic and tropical Pacific. We found most frequency histograms to be non‐Gaussian. The main departure from normal distribution is due to anomalous low‐salinity measurements creating a negative skewness. This conclusion is verified as a global phenomenon by examining statistics of mean‐median SSS difference within one‐degree squares. This quantity is found to be predominantly negative over the global ocean. These anomalous low‐salinity values may be due to rainfall events, but there are other plausible physical mechanisms, like frontal movement and eddy activity. There were also areas where the distributions were bimodal due to the presence of meandering fronts with little cross‐frontal mixing. Examples are shown where the non‐Gaussian nature of the distributions in the areas examined is both a short‐term and a long‐term phenomenon. That is, the distributions are skewed on a nearly instantaneous (∼1 month) basis and averaged over long time periods (1 + years). This has important implications for climatologies because the differences between mean and modal SSS, for the analyzed one‐degree squares, is of order 0.1. Furthermore, the implication for validation studies for remote sensing missions is that the studies must make enough measurements of SSS to determine the extent to which the probability density is not Gaussian.
Integration of the Clementine UV‐VIS spectral reflectance data and the Lunar Prospector gamma‐ray spectrometer data: A global‐scale multielement analysis of the lunar surface using iron, titanium, and thorium abundances
Authors: Chevrel S. D. , Pinet P. C. , Daydou Y. , Maurice S. , Lawrence D. J. , Feldman W. C. , Lucey P. G.
Published: December 2002

We present a statistical analysis, based on a systematic clustering method, of a data set integrating the global abundances maps of iron, titanium, and thorium derived from Clementine and Lunar Prospector. Homogeneous geological units are compositionally characterized and spatially defined in relation to the major rock types sampled on the Moon. With the lowest abundances in Fe, Ti, and Th found on the Moon, the lunar highlands terrains are quite homogeneous with two major large feldspathic units, one being slightly more mafic than the other. Two distinct regions with unique compositions are unambiguously identified: the Procellarum KREEP Terrane (PKT) and the South Pole–Aitken (SPA). The PKT, which includes all the units with Th abundances higher than 3.5 ppm (KREEP‐rich materials), is delimited by an almost continuous ring‐like unit. In particular, it includes the western nearside maria, except for Mare Humorum. Within the PKT a Th‐rich unit, corresponding to the highest Th concentrations found on the Moon, may represent KREEP volcanic deposits excavated from relatively shallow depth. With concentrations in Fe, Ti, and Th enhanced relative to the surrounding highlands, the South Pole–Aitken basin floor represents a large mafic anomaly on the farside, suggesting wide deposits of lower crust and possible mantle materials. However, due to indirect residual latitude effects in the Clementine spectral reflectance measurements, iron abundances might have been overestimated in SPA, thus implying that crustal materials, rather than mantle materials, might represent the dominant contributor to the mafic component exposed on the basin floor.