bluuebunny/crossref_metadata_2025 huggingface dataset:
Cycloaddition of bis‐1,3‐dipolar reagents to 1,3‐diarylprop‐2‐en‐1‐ones
Authors: Padmavathi V. , Siva Jyothi G. , Sreedhar N. Y. , Venugopal Reddy K. , Ramana Reddy T. V. , Bhaskar Reddy D.
Published: May 2003

Bis pyrazolines and isoxazolines were prepared by 1,3‐dipolar cycloaddition of benzene‐1,3/1,4‐dicarboxaldehyde dihydrazones and dioximes to 1,3‐diaryl‐prop‐2‐en‐1‐ones. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:379–383, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10169
An α‐hydrazinoalkylphosphonate as building block for novel N‐phosphonoalkylheterocycles
Authors: Li Zai‐Guo , Sun Hui‐Kai , Wang Qing‐Min , Huang Run‐Qiu
Published: May 2003

α‐Hydrazinoalkylphosphonate 3 is a useful building block for the syntheses of novel N‐phosphonoalkylheterocycles. N‐phosphonoalkylpyrazoles 8 and 9 were prepared by the cyclization reaction of 3 with multifunctioned ethenes 5 and 6 in ethanol under reflux. N‐Phosphonoalkyltriazole 10 was synthesized from 3 with N‐dimethylthiomethylene benzoyl amide 4 in ethanol under reflux. The structures were confirmed by IR, 1H NMR, mass spectroscopy, and elemental analysis. At the same time, the preparation of 4 was investigated. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:384–386, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10173
Alkylgermasesquioxide derivatives of tert‐butyl‐diacylhydrazines
Authors: Wang Qingmin , Huang Runqiu
Published: May 2003

N‐tert‐Butyl‐N‐benzoylhydrazine was synthesized by a new method. Its condensation and the condensation of its N,N′‐isomer with 3‐(trichlorogermyl)propionyl chloride provided N‐tert‐butyl‐N′‐(3‐trichlorogermyl)propionyl‐N‐benzoylhydrazine or its N,N,N′‐isomer, respectively, in good yields. Subsequent hydrolysis of the trichlorogermyl compounds using saturated sodium carbonate yielded the corresponding germasesquioxide derivatives that have good solubility in organic solvents. The structures of these compounds were confirmed by 1H NMR, IR, MS, and elemental analysis. The hydrolysis of organogermanium trichloride was studied, and the elimination of HGeCl3 was observed when the basicity was too high (pH > 10). © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:293–297, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10174
Clinicopathologic and immunohistochemical study of surgically treated primary gastric MALT lymphoma
Authors: Insabato Luigi , Di Vizio Dolores , Tornillo Luigi , D'Armiento Francesco P. , Siciliano Antonella , Milo Mario , Palmieri Giovanna , Pettinato Guido , Terracciano Luigi M.
Published: May 2003

Background and Objectives

B‐cell MALT lymphoma is a well‐recognized entity and its characterization as low‐grade (LG) and high‐grade (HG) lymphoma has been widely accepted. In the present study we reviewed a series of 95 surgical specimens of primary gastric MALT lymphoma selected between 1979 and 1998. Immunohistochemical expression of p53, bcl‐2, and Ki67 and Helicobacter pylori (Hp) infection was evaluated, along with a correlation with clinical outcome.

Methods

A morphologic and immunohistochemical analysis, including p53, bcl‐2, and Ki67 expression, was carried out in all cases. A complete follow‐up was obtained in 49 patients and in these cases a survival analysis was performed.

Results

bcl‐2 protein was highly expressed in 25 of 25 assessed LG tumors and in 20 of 24 assessed HG tumors. p53 protein was expressed in 13 of 25 assessed LG tumors and in 21 of 24 assessed HG tumors. High proliferation rate as expressed by Ki67 was detected in 15 of 25 assessed LG tumors and in 23 of 24 assessed HG tumors. Hp infection was detected in 11 of 16 assessed LG tumors and 2 of 10 assessed HG tumors. Median survival rates were 72 months for LG tumors and 24 months for HG tumors.

Conclusions

A significant inverse relationship between Hp infection and histological grade was found. High p53 expression and high‐proliferation rate correlated with HG tumors. However, a correlation between p53, bcl‐2, and Ki67 expression with clinical outcome was not found. J. Surg. Oncol. 2003;83:106–111. © 2003 Wiley‐Liss, Inc.
Heterogeneic expression of estrogen receptor between the primary tumor and the corresponding involved lymph nodes in patients with node‐positive breast cancer and its implications in patient outcome
Authors: Iguchi Chikage , Nio Yoshinori , Itakura Masayuki
Published: May 2003

Background and Objectives

The estrogen‐receptor (ER) status of breast cancers has typically been evaluated in primary tumors (PTs), and the influence of ER expression in the involved lymph nodes (LNs) on prognosis of the patients with node‐positive breast cancer remains unclear. The expression of ER was compared between PT and corresponding involved LNs in patients with node‐positive breast cancer.

Methods

Eighty‐seven patients with node‐positive breast cancer were immunohistochemically assessed to measure the expression of ER in PT and involved LN with anti‐ER monoclonal antibody.

Results

Thirty‐five (40.2%) of PTs and 26 (29.9%) of involved LNs were evaluated as ER(+). The ER expression in PTs was significantly correlated with that in involved LNs (P < 0.0001), and the ER expression was almost the same in both the PT and corresponding involved LN in 66 cases (75.9%): both (+), 20 (23.0%); and both (−), 46 (52.9%). However, ER expression differed in 21 cases (24.1%) between involved LN and the corresponding PT: PT‐ER(+)/LN‐ER(−), 15 (17.2%); and PT‐ER(−)/LN‐ER(+), 6 (6.9%). The survival of patients with ER(+)‐PT was significantly better than that of ER(−)‐PT patients (P = 0.0086), but ER expression in involved LN did not have any significant effect on patient survival. Furthermore, when survival periods were grouped by coexpression of ER in the PT and involved LN, the best survival was seen in the PT‐ER(+)/LN‐ER(−) group (P < 0.001 vs. others). In the patients, who received adjuvant endocrine therapy, the survival of the PT‐ER(+) group was significantly better than that of PT‐ER(−) group (P = 0.0145), but LN‐ER expression did not show any significant influence on the survival rate. Multivariate analysis demonstrated that clinical stage and ER‐expression in the PT were significant variables, but ER expression in the involved LN was not.

Conclusions

The ER expression was discordant between PT and involved LN in about 24% of the breast cancers evaluated, and ER expression in involved LNs had less influence on patient prognosis than ER expression in the corresponding PT. J. Surg. Oncol. 2003;83:85–93. © 2003 Wiley‐Liss, Inc.
Surgeon volume compared to hospital volume as a predictor of outcome following primary colon cancer resection
Authors: Schrag Deborah , Panageas Katherine S. , Riedel Elyn , Hsieh Lillian , Bach Peter B. , Guillem Jose G. , Begg Colin B.
Published: May 2003

Background and Objectives

A strong association between high hospital procedure volume and survival following colon cancer resection has been demonstrated. However, the importance of surgeon case volume as a determinant of outcome has been less well studied, and it is unclear whether hospital or surgeon volume is the more powerful predictor of outcomes.

Methods

A retrospective population‐based cohort study utilizing the Surveillance, Epidemiology, and End Results (SEER)‐Medicare linked database identified 24,166 colon cancer patients aged 65 years and older who had surgery for a primary tumor diagnosed in 1991–1996 in a SEER area. Hospital and surgeon‐specific procedure volume was ascertained based on the number of claims submitted over the 6‐year study period. Outcome measures were mortality at 30 days and 2 years, overall survival, and the frequency of operations requiring an intestinal stoma. Age, sex, race, comorbid illness, cancer stage, socioeconomic status, emergent hospitalization, and the presence of obstruction/perforation were used to adjust for differences in case‐mix.

Results

After adjusting for surgeon procedure volume, high hospital procedure volume remained a strong predictor of low post‐operative mortality rates (P < 0.001 for each outcome with and without adjustment for surgeon procedure volume). Surgeon‐specific procedure volume was also an important predictor of surgical outcomes (P = 0.002 for 30‐day mortality, P = 0.001 for 2‐year mortality), although this effect was attenuated after adjusting for hospital volume (P = 0.03 for 30‐day mortality, P = 0.02 for 2‐year mortality). Hospital volume and surgeon volume were each an important predictor of the ostomy rate. Among high volume institutions and surgeons, individual providers with unusually high ostomy rates could be identified.

Conclusions

Both hospital and surgeon‐specific procedure volume predict outcomes following colon cancer resection; but hospital volume may exert a stronger effect. Therefore, efforts to optimize the quality of colon cancer surgery should focus on multidisciplinary aspects of hospital care rather than solely on intraoperative technique. J. Surg. Oncol. 2003;83:68–78. © 2003 Wiley‐Liss, Inc.
Soluble Fas (sFas) and soluble Fas ligand (sFas‐L) balance in laryngeal carcinoma before and after surgical treatment
Authors: Pignataro Lorenzo , Arisi Elena , Sambataro Giuseppe , Corsi Massimiliano Marco
Published: May 2003

Background and Objectives

Fas and its specific ligand (Fas‐L), both of which are involved in apoptosis, exist in membrane‐bound and soluble forms. The soluble forms (sFas and sFas‐L) have been observed in various tumours, but their clinical significance has not yet been clarified. The aim of this study was to assess serum sFas and sFas‐L levels in patients with laryngeal squamous cell carcinoma (LSCC) and their possible correlations with surgical treatment.

Methods

Serum sFas and sFas‐L levels were determined by ELISA in samples taken from 26 LSCC patients on the day before surgery (T0), and 2 weeks (T1) and 6 months after surgery (T2), and in samples taken from 35 healthy volunteers.

Results

The mean serum sFas levels in the 35 healthy volunteers and the 26 LSCC patients at T0 were respectively 5941 ± 411 pg/ml and 6290 ± 652 pg/ml (P = 0.63), and the mean serum sFas‐L levels were 0.1 ± 0.05 ng/ml and 2.95 ± 0.8 ng/ml (P < 0.0001). After surgery, there was a statistically significant decrease in sFas at both T1 (P < 0.05) and T2 (P < 0.01), and in sFas‐L at T2 (P < 0.01).

Conclusions

The decrease in sFas and sFas‐L levels after surgery suggest that they may be produced by or closely linked to tumour cells. Larger prospective clinical studies of patients with LSCC will be needed to establish the clinical significance of sFas and sFas‐L, as reported for other neoplasms. J. Surg. Oncol. 2003;83:112–115. © 2003 Wiley‐Liss, Inc.
Current management of mucosal melanoma of the head and neck
Authors: Medina Jesus E. , Ferlito Alfio , Pellitteri Phillip K. , Shaha Ashok R. , Khafif Avi , Devaney Kenneth O. , Fisher Samuel R. , O'Brien Christopher J. , Byers Robert M. , Robbins K. Thomas , Pitman Karen T. , Rinaldo Alessandra
Published: May 2003

While mucosal‐based melanomas of the head and neck region are uncommon lesions, when they do arise they usually follow an inexorably aggressive course. Experience with these tumors is, necessarily, limited; as such, well‐worked out treatment protocols for the treatment of such lesions are in short supply. It appears as though mucosal melanomas (MuMs) develop more frequently in the nasal cavity and paranasal sinus region, and less often in the oral cavity. It seems that the incidence of nodal metastasis is significantly lower for sinonasal MuMs than it is for MuMs of the oral cavity; this observation may influence decisions about performing neck dissection as a function of location of the primary MuM. At present, surgical excision remains the mainstay of treatment; however, anatomical complexities within the region can hamper attempts at complete excision. Radiotherapy has not traditionally been relied on for routine treatment of MuM, although some recent reports have challenged this view. Chemotherapy is, at present, employed principally in the treatment of disseminated disease and for palliation. As a diagnostic matter, MuM belongs to the class of tumors that, on light microscopy, may with some regularity be confused with other malignancies (including sarcomas, plasmacytomas, and carcinomas); as a consequence, this is a diagnosis which is often best confirmed by way of ancillary testing via immunohistochemical studies. A better grasp of the best means of treating MuM will likely come only when large referral centers are able to pool their experiences with these uncommon yet virulent malignancies. J. Surg. Oncol. 2003;83:116–122. © 2003 Wiley‐Liss, Inc.
The role of preoperative ultrasound scan in detecting lymph node metastasis before sentinel node biopsy in melanoma patients
Authors: Riccardo Rossi Carlo , Mocellin Simone , Scagnet Barbara , Foletto Mirto , Vecchiato Antonella , Pilati Pierluigi , Tregnaghi Alberto , Zavagno Giorgio , Stramare Roberto , Rubaltelli Leopoldo , Montesco Cristina , Borsato Simonetta , Rubello Domenico , Lise Mario
Published: May 2003

Background and Objectives

To evaluate the efficacy of preoperative ultrasound (US) scanning in identifying lymph node metastasis before sentinel node biopsy (SNB), we conducted a prospective study on 125 patients with primary cutaneous melanoma (CM).

Methods

We prospectively enrolled 125 patients with >1 mm thick CM and candidate for SNB. Preoperatively, patients underwent US scanning of regional lymphatic basins and FNA of suspected lymph nodes (LN). All patients underwent lymphatic mapping and SNB.

Results

Combined with fine‐needle aspirate (FNA) of suspect LN, US scan allowed the correct preoperative detection of 12 out of 31 histologically positive lymphatic basins, specificity and sensitivity being 100 and 39%, respectively. The false negative rate (61%) was mainly linked to tumor deposits less than 2 mm in diameter, which can be considered the current spatial resolution limit of this technique.

Conclusions

Preoperative US scan could reduce the number of SNB, thus avoiding the stress of this surgical procedure in ∼10% of patients and reducing health care costs. As a non‐invasive and relatively inexpensive technique, lymph node US scan can be part of the preoperative staging process of patients' candidate for SNB in order to avoid unnecessary surgical procedures. J. Surg. Oncol. 2003;83:80–84. © 2003 Wiley‐Liss, Inc.
Interfacial Modification of Polystyrene‐block‐polybutadiene‐block‐polystyrene/Magnesium Hydroxide Composites, 1
Authors: Liauw Christopher Mark , Dumitru Paul , Lees Graham Clayton , Clemens Mark Lawrence , Rothon Roger Norman
Published: May 2003

Composites based on polystyrene‐block‐polybutadiene‐block‐polystyrene (SBS triblock thermoplastic elastomer) and magnesium hydroxide (Mg(OH)2) (5–60 wt.‐%) have been prepared by twin screw extrusion. Interfacial modifiers included dispersants, i.e., isostearic acid, oleic acid, stearic acid; and coupling agents, i.e., maleanised polybutadiene and vinyltriethoxysilane. In each case, approximately one monolayer of treatment was used. A dual bore motor driven extrusion rheometer was used for assessment shear and elongation flow behavior (Cogswell's method) over a shear rate range of 100 s−1 to 5 000 s−1. Untreated filler and filler treated with coupling agents gave composites that become increasingly pseudoplastic as filler level increased. Fatty acid structure was shown to have some influence over the level of melt viscosity reduction normally associated with such treatments; stearic acid gave the most pronounced reduction in melt viscosity possibly due to the tightly packed monolayer. Elongational flow properties, determined using Cogswell's method, indicated significant chain extension/branching of the bulk matrix when high levels of untreated filler were present and long range filler‐matrix interaction in composites modified with maleanised polybutadiene.

Elongational viscosity versus extensional stress (obtained by Cogswell's method) for SBS blended with filler surface treatments (□) unfilled matrix, and unfilled matrix plus (•) Hist and (▵) MPBD.

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Elongational viscosity versus extensional stress (obtained by Cogswell's method) for SBS blended with filler surface treatments (□) unfilled matrix, and unfilled matrix plus (•) Hist and (▵) MPBD.
One‐Step Synthesis of Hybrid Composites of Poly(6‐hexanelactam) Combining Solid Tribological Additives and Reinforcing Components
Authors: Horský Jaroslav , Kolařík Jan , Fambri Luca
Published: May 2003

Four types of composites of polyamide 6 with hybrid tribological additives were synthesized via anionic adiabatic “in situ” polymerization of 6‐hexanelactam (ε‐caprolactam) initiated with metallic sodium and activated with cyclic trimer of phenyl isocyanate or diphenylmethane 4,4′‐diisocyanate. The optimization of the initiator/activator systems in the range of 0.3 to 1.2 mol‐% and of the initial polymerization temperatures from 125 to 150 °C preceded the composite preparation. Combinations of fillers and their maximum applied concentrations (in wt.‐%) were the following: MoS2/graphite/oil (5/16/9), carbon fibers/graphite/oil (5/20/10), copper phthalocyanine (7), and B2O3 (11). Analysis of selected composites encompassed water extraction, DSC, and DMTA measurements. All tested fillers decreased the polymerization rate, polymer yield, melting temperature and crystalline fraction. Polymerization rate constants of the neat polyamide 6 obtained for various initial temperatures obeyed the Arrhenius plot giving an average activation energy value of 78.6 kJ · mol−1.

Rate of polymerization as a function of the total fillers content in adiabatic anionic polymerization of 6‐hexanelactam (A: MoS2 + G/O, Na/PIC, B: CPC, Na/MDI, C: MoS2 + G/O, Na/MDI, D: CF + G/O Na/MDI).

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Rate of polymerization as a function of the total fillers content in adiabatic anionic polymerization of 6‐hexanelactam (A: MoS2 + G/O, Na/PIC, B: CPC, Na/MDI, C: MoS2 + G/O, Na/MDI, D: CF + G/O Na/MDI).
Dissolution and Enzymatic Degradation Studies Before and After Artificial Ageing of Silk‐ or Linen‐Reinforced Gelatin Laminates, 1
Authors: Boyanova M. , Stambolieva N. , Apostolov A. A. , Fakirov S.
Published: May 2003

In an attempt to overcome the poor mechanical properties of native, i.e., untreated gelatin, laminates based on gelatin and gelatin/starch blend reinforced with fabrics (linen or silk) were prepared by melt pressing. The mechanical properties of fresh and artificially aged samples were reported previously. In the present series of two consecutive papers we present data concerning the dissolution and biodegradation of these laminates. A two‐step procedure for treatment of the laminates was used. The first step is treatment with an aqueous buffer solution, the second with a buffered solution of the enzyme subtilisin. The time‐course of the absorbance at 280 nm of the “washing” solutions was followed. A number of kinetic characteristics was determined and discussed with respect to laminate composition and their treatments. In the present Part 1 about the environmental behavior of these new biodegradable materials, the non‐enzymatic solubilization in water and buffer solution (i.e., simple dissolution) of fresh and artificially aged samples is described. The dissolution process was followed spectrophotometrically as well as by the weight losses. It was found that gelatin‐based silk‐ or linen‐reinforced laminates were subject to dissolution, similarly to the gelatin and gelatin‐based materials studied in previous works. In addition, it was established that the thermal treatment of the laminates during their melt pressing leads to postcondensation reactions and crosslinking of the gelatin macromolecules. Similar reactions occur between the matrix and the reinforcing element silk, thus improving their mutual adhesion. Decreased gelatin dissolution ability was observed after the thermal treatment, in the presence of reinforced fabrics and upon “additional” crosslinking with methylenedi(p‐phenyl) diisocyanate. The untreated gelatin is the only one that dissolves completely in water. The artificially aged samples tend to dissolve better than the respective fresh samples due to degradation processes during aging.

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Fracture Behaviour of Styrene/Butadiene Block Copolymers having Different Molecular Architecture
Authors: Adhikari Rameshwar , Lach Ralf , Michler Goerg H. , Weidisch Roland , Knoll Konrad
Published: May 2003

The crack toughness behaviour of styrene/butadiene block copolymers of triblock and star architectures was investigated using instrumented Charpy impact testing. In order to evaluate adequately the toughness behaviour of the investigated materials, different concepts of elastic‐plastic mechanics (J‐integral and crack‐tip opening displacement, CTOD concepts) were used. Although the lamellar block copolymers showed a remarkably enhanced ductility in the tensile test than the neat block copolymer having hexagonal PB cylinders in PS matrix, no pronounced difference in crack toughness was found. This behaviour implies that the tensile strain cannot be regarded as the only parameter defining the toughness value. A brittle/tough transition was observed in a lamellar star block copolymer on blending with a linear thermoplastic elastomeric SBS triblock copolymer.

SEM micrograph showing the details of the stable crack propagation region in a binary block copolymer blend.

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SEM micrograph showing the details of the stable crack propagation region in a binary block copolymer blend.
Crystallization Controlled by Silicate Surfaces in Nylon 6‐Clay Nanocomposites
Authors: Maiti Pralay , Okamoto Masami
Published: May 2003

The crystallization behavior of pure nylon 6 (N6) and its nanocomposite with montmorillonite has been studied in detail. The crystallization rate of N6 is faster in the presence of clay compared to pure N6, as revealed by light scattering experiments. Nylon 6 crystallizes exclusively in the γ‐form in the nanocomposite because of the epitaxial crystallization, which is also revealed from the transmission electron microscopic images (sandwiched structure) of the crystallized sample. The storage modulus of the nanocomposite is always higher than the pure nylon 6, irrespective of crystallization temperatures. Much higher increment of storage modulus for pure nylon 6 with increasing crystallization temperature is explained by the higher amount of the thermally stable α‐form at higher temperature. A unique mechanism has been proposed to illustrate the crystallization behavior of nylon 6 in the presence of the clay particles.

Transmission electron micrograph of N6C3.7 crystallized at 210 °C, showing the typical shish‐kebab type of structure.

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Transmission electron micrograph of N6C3.7 crystallized at 210 °C, showing the typical shish‐kebab type of structure.
Synthesis of Poly(methyl‐co‐trifluoropropyl)silsesquioxanes and Their Thin Films for Low Dielectric Application
Authors: Hyeon‐Lee Jingyu , Kim Woon Chun , Min Sung Kyu , Ree Hee‐Woo , Yoon Do Y.
Published: May 2003

Poly(methyl‐co‐trifluoropropyl)silsesquioxanes (P(M‐co‐TFP)SSQs) were prepared using methyltrimethoxysilane (MTMS) and trifluoropropyltrimethoxysilane (TFPTMS). The molecular weight, microstructure of the copolymers and properties of their thin films have been changed by adjusting reaction parameters such as the molar ratio of water to silane, the molar ratio of catalyst to silane, reaction time, solvent content, and temperature. The refractive index of the copolymer thin film decreased from 1.404 to ca. 1.348 as curing temperature was increased to 420 °C. The dielectric constant of the film decreased with an increase of the molecular weight of the copolymer, and the lowest dielectric constant obtained was ca. 2.2. Hardness and elastic modulus of the thin films were 0.7 and 5 GPa, respectively. Crack velocity was measured to be 10−11 m/s at the film thickness of around 0.9 μm under aqueous environment.

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A mathematical model for impulse resistance welding
Authors: Duderstadt F. , Hömberg D. , Khludnev A. M.
Published: May 2003

We present a mathematical model of impulse resistance welding. It accounts for electrical, thermal and mechanical effects, which are non‐linearly coupled by the balance laws, constitutive equations and boundary conditions. The electrical effects of the weld machine are incorporated by a discrete oscillator circuit which is coupled to the field equations by a boundary condition.

We prove the existence of weak solutions for a slightly simplified model which however still covers most of its essential features, e.g. the quadratic Joule heat term and a quadratic term due to non‐elastic energy dissipation.

We discuss the numerical implementation in a 2D setting, present some numerical results and conclude with some remarks on future research. Copyright © 2003 John Wiley & Sons, Ltd.
Multiplicity of solutions for a class of non‐symmetric eigenvalue hemivariational inequalities
Authors: Ciulcu Claudiu , Motreanu Dumitru , Rădulescu Vicenţiu
Published: May 2003

The aim of this paper is to establish the influence of a non‐symmetric perturbation for a symmetric hemivariational eigenvalue inequality with constraints. The original problem was studied by Goeleven et al. (Math. Methods Appl. Sci. 1997; 20: 548) who deduced the existence of infinitely many solutions for the symmetric case. In this paper it is shown that the number of solutions of the perturbed problem becomes larger and larger if the perturbation tends to zero with respect to a natural topology. The approach relies on topological methods in non‐smooth critical point theory leading to this new multiplicity information. Copyright © 2003 John Wiley & Sons, Ltd.
Large displacement FEM modelling of the cone penetration test (CPT) in normally consolidated sand
Authors: Susila Endra , Hryciw Roman D.
Published: May 2003

A new finite element model based on a large strain formulation has been developed to study cone penetration in normally consolidated sand. An auto‐adaptive remeshing technique was utilized for handling the very large distortion of sand surrounding the cone tip. A frictional contact interface utilizing Mohr–Coulomb's theory was chosen to represent interactions between the surface of the cone and sand. To model the sand behaviour, the non‐associated Drucker–Prager constitutive model was selected. ABAQUS, a commercial finite element software package, was used to implement the model. The explicit solution algorithm was chosen due to its effectiveness for complicated contact problems. Analysis results proved that the model successfully captured the cone penetration behavior in sand. In addition, a chart to predict internal friction angles based on cone tip resistance for different vertical effective stresses was provided. This paper also shows a typical distribution of sleeve resistance, tip resistance—penetration relationship, and typical contours of vertical, horizontal, and shear stresses in normally consolidated sand. Finally, a non‐uniform resistance was found along the length of the friction sleeve. Copyright © 2003 John Wiley & Sons, Ltd.
Correction to the gas phase pressure term in the continuum model for partially saturated granular media presented by Pietruszczak and co‐workers
Authors: Iveson Simon M.
Published: May 2003

Pietruszczak and coworkers (Internat. J. Numer. Anal. Methods Geomech. 1994; 18(2):93–105; Comput. Geotech. 1991; 12( ):55–71) have presented a continuum‐based model for predicting the dynamic mechanical response of partially saturated granular media with viscous interstitial liquids. In their model they assume that the gas phase is distributed uniformly throughout the medium as discrete spherical air bubbles occupying the voids between the particles. However, their derivation of the air pressure inside these gas bubbles is inconsistent with their stated assumptions. In addition the resultant dependence of gas pressure on liquid saturation lies outside of the plausible range of possible values for discrete air bubbles. This results in an over‐prediction of the average bulk modulus of the void phase. Corrected equations are presented. Copyright © 2003 John Wiley & Sons, Ltd.
Consistent mesh tying methods for topologically distinct discretized surfaces in non‐linear solid mechanics
Authors: Laursen T. A. , Heinstein M. W.
Published: May 2003

This work presents a new technique for joining dissimilar meshes in non‐linear finite element analysis, with the novel result that the adjoining surfaces do not need to be spatially coincident for patch tests to be passed. The work builds in some sense on results previously presented by Dohrmann et al. (International Journal for Numerical Methods in Engineering 1991; 40:1205), but considerably generalizes upon the results presented there. Most importantly, it is shown that consistency of the tied finite element formulation may be achieved such that implementation of element formulations is not affected, through the use of a three‐field variational principle applied over the contacting region. A key conclusion of the work is that although the approach advocated bears some resemblance to mortar element schemes for contact analysis (see, for example, McDevitt and Laursen, International Journal for Numerical Methods in Engineering 2000; 48:1525), a straightforward application of a mortaring scheme is not sufficient to guarantee patch test passage when dissimilar meshing of curved surfaces leads to local open volumes (or overlaps) between tied surfaces in their reference configurations. The proposed algorithm is demonstrated through a number of numerical examples performed within a matrix‐free non‐linear equation solving framework. Published in 2003 by John Wiley & Sons, Ltd.
Variational multiscale methods to embed the macromechanical continuum formulation with fine‐scale strain gradient theories
Authors: Garikipati K.
Published: May 2003

A variational basis is presented to link fine‐scale theories of material behaviour with the classical, macromechanical continuum theory. The approach is based on the weak form of the linear momentum balance equations, and a separation of the weighting function and displacement fields into coarse and fine‐scale components. Coarse and fine‐scale weak forms are defined. The latter is used to introduce a strain gradient theory that operates at finer scales of deformation. Attention is focused upon applications requiring the enhanced physical accuracy of the fine‐scale strain gradient theory, without the computational cost of discretization that spans the range from coarse to fine scales. A variationally consistent method is developed to embed the fine‐scale strain gradient theory in the macromechanical formulation. The embedding is achieved by eliminating the fine‐scale displacement field from the problem. Two examples demonstrate the numerical efficiency of the method, while retaining physical and mathematical properties of the fine‐scale strain gradient theory. Copyright © 2003 John Wiley & Sons, Ltd.
Exponential convergence and H‐c multiquadric collocation method for partial differential equations
Authors: Cheng A. H.‐D. , Golberg M. A. , Kansa E. J. , Zammito G.
Published: May 2003

The radial basis function (RBF) collocation method uses global shape functions to interpolate and collocate the approximate solution of PDEs. It is a truly meshless method as compared to some of the so‐called meshless or element‐free finite element methods. For the multiquadric and Gaussian RBFs, there are two ways to make the solution converge—either by refining the mesh size h, or by increasing the shape parameter c. While the h‐scheme requires the increase of computational cost, the c‐scheme is performed without extra effort. In this paper we establish by numerical experiment the exponential error estimate ϵ ∼ O(λ√c̄h) where 0 < λ < 1. We also propose the use of residual error as an error indicator to optimize the selection of c. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 19: 571–594, 2003
Exponential meshes and three‐dimensional computation of a magnetic field
Authors: Alouges F. , Laminie J. , Mefire S. M.
Published: May 2003

We describe the simulation of an exterior problem using a magnetic field deriving from magnetostatics, with a numerical method mixing the approaches of C. I. Goldstein and L.‐A. Ying. This method is based on the use of a graded mesh obtained by gluing homothetic layers in the exterior domain. On this mesh, we use an edge elements discretization and a recently proposed mixed formulation. In this paper, we provide both a theoretical and numerical study of the method. We establish an error estimate, describe the implementation, propose some preconditioning techniques and show the numerical results. We also compare these results with those obtained from an equivalent boundary elements approach. In this way, we retain that our method leads to a practical numerical implementation, a saving of storage, and turns out to be an alternative to the classical boundary elements method. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 19: 595–637, 2003
The modified characteristic finite difference fractional steps method for the coupled system of fluid dynamics in porous media and its analysis
Authors: Yuan Yirang
Published: May 2003

For the coupled system of multilayer fluid dynamics in porous media, the modified characteristic finite difference fractional steps method applicable to parallel arithmetic is put forward and two‐dimensional and three‐dimensional schemes are used to form a complete set. Some techniques, such as calculus of variations, energy method, piecewise biquadratic interpolation, multiplicative commutation rule of difference operators, decomposition of high order difference operators and prior estimates are adopted. Optimal order estimates in L2 norm are derived to determine the error in the approximate solution. This method has already been applied to the numerical simulation of multilayer fluid dynamics in porous media. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 19: 665–681, 2003.
Localized triangular differential quadrature
Authors: Zhong Hongzhi , Hua Yongxia , He Yuhong
Published: May 2003

A localized triangular differential quadrature method is introduced in this article. Not only is the existing limitation on the approximation order in the triangular differential quadrature eliminated but also the convergent rate is enhanced in the new method. As an example to validate the new method, elastic torsion of prismatic shaft with regular polygonal cross section is studied and excellent agreement with available theoretical and analytic solutions is reached. It is believed that the present work further widens the applicability of the triangular differential quadrature technique. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 19: 682–692, 2003
Software modelling of grid‐connected photovoltaic buildings
Authors: Argul F. J. , Castro M. , Delgado A. , Carpio J. , Peire J.
Published: May 2003

This paper presents a software tool, freely available on the Worldwide Web, that can be concurrently run by multiple users on different hardware–software platforms. To evaluate the limits and competitiveness of PV energy in Spain, several companies, utilities and institutions have been working together in a project called FotoRED. Within this project, several computer tools have been developed to analyse the potential of connecting photovoltaic stations to the utility grid. One of these tools is the simulator presented here, a program to estimate the energy balance and economic behaviour of grid‐connected PV buildings. Depending on several construction parameters of the building, the photovoltaic generators installed, the geographical location, weather conditions, etc., the program estimates the energy consumed in the building, the photovoltaic energy that can be generated on‐site and the resulting energy balance on a daily, monthly and yearly basis. The economic behaviour of the building can also be simulated over a 30‐year period, generating cash‐flow diagrams, investment payback curves and other economic information to describe the building's expected performance. Many building designs and several existing buildings have been simulated with this tool so far. One example of these is presented and the conclusions reached during several simulation runs are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Properties of 19.2% efficiency ZnO/CdS/CuInGaSe2thin‐film solar cells
Authors: Ramanathan Kannan , Contreras Miguel A. , Perkins Craig L. , Asher Sally , Hasoon Falah S. , Keane James , Young David , Romero Manuel , Metzger Wyatt , Noufi Rommel , Ward James , Duda Anna
Published: May 2003

We report the growth and characterization of record‐efficiency ZnO/CdS/CuInGaSe2thin‐film solar cells. Conversion efficiencies exceeding 19% have been achieved for the first time, and this result indicates that the 20% goal is within reach. Details of the experimental procedures are provided, and material and device characterization data are presented. Published in 2003 by John Wiley & Sons, Ltd.
Stress manifestation in high school students: An Australian sample
Authors: Moulds John D.
Published: May 2003

Stress symptoms associated with main daily hassles were assessed among grades 7, 9 and 11 students in all‐female, all‐male, and coeducational Catholic high schools in Western Sydney, Australia. Factor analysis identified the stress manifestation domains of anxiety, anger, and physiological arousal. Differences in these are examined and a conceptual model of stress manifestation is proposed. Implications of the findings for school‐based stress management programs are addressed. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 391–402, 2003.
Sources of variance in curriculum‐based measures of silent reading
Authors: Brown‐Chidsey Rachel , Davis Linda , Maya Cynthia
Published: May 2003

Curriculum‐Based Measurement silent reading (CBM‐SR) items have been found to be reliable and valid for measuring reading comprehension skills This generalizability study reports the findings from administration of three CBM‐SR passages to fifth through eighth grade students in one school district. Using Repeated Measures Analyses of Variance (RMANOVA) procedures, the statistical probability of performance on the CBM‐SR task as a differential indicator of reading comprehension skill was found to be significant among students in different grade levels and between students who did and did not receive special education services. Follow‐up analyses were conducted using generalizability theory to estimate the amount of variance in CBM‐SR scores from individual score differences, grade levels, and special education status. The results indicated that on two of the passages, variability in CBM‐SR scores came primarily from grade level differences in scores on the tasks, while on the third passage, the differences were most attributable to individual differences in scores, regardless of grade level or special education services. Implications for the use of CBM‐SR items for routine assessment of students' reading skills are discussed. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 363–377, 2003.
A school‐based violence prevention model for at‐risk eighth grade youth
Authors: Rollin Stephen A. , Kaiser‐Ulrey Cheryl , Potts Isabelle , Creason Alia Haque
Published: May 2003

This study examined the effectiveness of a school and community‐based violence prevention program for at‐risk eighth‐grade students in three public schools in Florida. School officials matched intervention students with community‐based mentors in an employment setting to allow targeted youth to explore careers and receive one‐on‐one intervention from an adult mentor. Intervention students were compared to a control group of students not receiving mentorship services. This study used MANOVA and t‐test analyses to examine six outcomes measured: (1) unexcused absences; (2) number of in‐school suspensions; (3) number of days of in‐school suspensions; (4) number of out‐of‐school suspensions; (5) number of days of out‐of‐school suspensions; and (6) total number of infractions committed on school property. The findings suggested that mentored students, as compared to control group students, had significant reductions in total number and days of suspensions, days of sanction, and infractions committed on school property. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 403–416, 2003.
New aliphatic poly(ester‐carbonates) based on 5‐methyl‐5‐allyloxycarbonyl‐1,3‐dioxan‐2‐one
Authors: Mullen Brian D. , Tang Chau N. , Storey Robson F.
Published: May 2003

The synthesis, characterization, and ring‐opening polymerization of a new cyclic carbonate monomer containing an allyl ester moiety, 5‐methyl‐5‐allyloxycarbonyl‐1,3‐dioxan‐2‐one (MAC), was performed for the first time. MAC was synthesized in five steps in good yield beginning from the starting material, 2,2‐bis(hydroxymethyl)propionic acid. Subsequent polymerization and copolymerizations of the new cyclic carbonate with rac‐lactide (rac‐LA) and ϵ‐caprolactone (CL) were attempted. Rac‐LA copolymerized well with MAC, but CL copolymerizations produced insoluble products. Oligomeric macroinitiators of MAC and rac‐LA were synthesized from stannous ethoxide, and both macroinitiators were used for the controlled ring‐opening polymerization of rac‐LA. The polymerization kinetics were examined by monitoring the disappearance of the characteristic CO ring stretch of the monomer at 1240 cm−1 with real‐time in situ Fourier transform infrared spectroscopy. Postpolymerization oxidation reactions were conducted to epoxidize the unsaturated bonds of the MAC‐functionalized polymers. Epoxide‐containing polymers may allow further organic transformations with various nucleophiles, such as amines, alcohols, and carboxylic acids. NMR was used for microstructure identification of the polymers, and size exclusion chromatography and differential scanning calorimetry were used to characterize the new functionalized poly(ester‐carbonates). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1978–1991, 2003
Vinyl‐type polymerization of norbornene by nickel(II) bisbenzimidazole catalysts
Authors: Patil Abhimanyu O. , Zushma Stephen , Stibrany Robert T. , Rucker Steven P. , Wheeler Louise M.
Published: May 2003

Novel nickel(II) bisbenzimidazole complexes were prepared via a three‐step synthetic procedure consisting of aniline/diacid condensation, ligand N‐alkylation, and metal complexation. The complexes were characterized by X‐ray crystallography and found to possess a pseudotetrahedral geometry. Upon activation with methylaluminoxane, these nickel bisbenzimidazoles did not polymerize simple olefins (e.g., ethylene, propylene, and 1‐butene) but were found to carry out the rapid and efficient polymerization of norbornene. The polynorbornene products were characterized by gel permeation chromatography/light scattering, 13C NMR, and IR, and their Mark–Houwink and dn/dc parameters were determined. The molecular weights of the polynorbornenes were very high (weight‐average molecular weight = 587,000–797,000 g/mol). 13C NMR suggested that the polymerization occurred via vinyl addition (i.e., a 2,3‐linked polymer); no ring‐opened product was observed. Thermogravimetric analysis indicated that the polynorbornenes were stable up to 400 °C under nitrogen. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2095–2106, 2003
Synthesis of poly(chitosan‐N‐isopropylacrylamide) complex particles with the method of soapless dispersion polymerization
Authors: Lee Chia‐Fen , Wen Chia‐Jen , Chiu Wen‐Yen
Published: May 2003

Crosslinked poly(chitosan‐N‐isopropylacrylamide) [poly(NIPAAM‐chitosan)] complex particles were successfully synthesized with the method of soapless dispersion polymerization. The anionic initiator ammonium persulfate (APS) and the cationic initiator 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride (AIBA) were used to initiate the copolymerization. The poly(NIPAAM‐chitosan) copolymer particles synthesized with APS as the initiator had a homogeneous morphology, whereas the copolymer particles synthesized with AIBA as the initiator showed a core–shell morphology. In addition, various variables such as the particle size, reaction rate, and ζ potential were taken into account. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2053–2063, 2003
Synthesis of polyesters with pendant oxetane groups by the chemoselective alternating copolymerization of 3‐ethyl‐3‐(glycidyloxymethyl)oxetane with carboxylic anhydride and its photochemical reaction
Authors: Kudo Hiroto , Ueda Kensuke , Sano Naotaka , Nishikubo Tadatomi
Published: May 2003

The synthesis of polyesters with pendant oxetane groups by the chemoselective alternating copolymerization of 3‐ethyl‐3‐(glycidyloxymethyl)oxetane (EGMO) with carboxylic anhydride and the photochemical reaction of the resulting polymer was examined. The alternating copolymerization of EGMO with phthalic anhydride proceeded chemoselectively with quaternary onium salts under appropriate reaction conditions, and the corresponding soluble polymers with pendant oxetane groups with number‐average molecular weights of 4700–7200 were obtained in 72–87% yields. Furthermore, the photochemical reaction of the resulting polymers was examined with certain photoacid generators in the film state upon UV irradiation, and it was found that the photocrosslinking reaction of the pendant oxetane groups proceeded smoothly to give the insoluble polymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1952–1961, 2003
Anionic polymerization of methyl methacrylate initiated with late transition‐metal halides/organolithium/triisobutylaluminum systems
Authors: Ihara Eiji , Todaka Tsuyoshi , Inoue Kenzo
Published: May 2003

Anionic polymerization of methyl methacrylate (MMA) initiated with late transition‐metal halides [manganese chloride (MnCl2), iron dichloride (FeCl2), iron trichloride (FeCl3), cobalt chloride (CoCl2), or nickel bromide (NiBr2)]/organolithium [nButyllithium (nBuLi) or phenyllithium (PhLi)]/triisobutylaluminum (iBu3Al) systems is described. Except for the system with NiBr2, the polymerizations of MMA afforded narrow molecular weight distribution poly(methyl methacrylate)s (PMMAs) with high molecular weights in quantitative yields at 0 °C in toluene. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) analyses of the PMMAs obtained by the systems with FeCl2, FeCl3, and CoCl2 revealed that the polymers had hydrogen (H) at both chain ends. Accordingly, the reaction of the transition‐metal halides with the organolithium in the presence of iBu3Al should result in the formation of transition‐metal hydride [M‐H]− species, which was nucleophilic enough to initiate the MMA polymerization. Because the presence of a six‐membered cyclic structure resulting from backbiting was confirmed from the MALDI‐TOF MS analyses of the PMMA obtained with the metal halide (FeCl2, FeCl3, or CoCl2)/organolithium systems in the absence of iBu3Al, the introduction of H at the ω‐chain end indicated that iBu3Al should prevent the backbiting. However, the MnCl2/nBuLi/iBu3Al initiating system gave PMMAs bearing H at the α chain end and six‐membered cyclic structure at the ω chain end. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1962–1977, 2003