bluuebunny/crossref_metadata_2025 huggingface dataset:
Symptoms and signs of primary melanoma
Authors: Negin Benjamin P. , Riedel Elyn , Oliveria Susan A. , Berwick Marianne , Coit Daniel G. , Brady Mary S.
Published: July 2003

BACKGROUND

Operative management of patients with cutaneous melanoma is guided primarily by the pathologic determination of Breslow depth. Differentiating early from more advanced melanoma is not always straightforward and may be complicated by pathologic misdiagnosis, inappropriate biopsy techniques, or poor specimen handling. Inconsistencies between the patient's history and the pathologist's interpretation may alert the physician to the possibility of misdiagnosis. In this setting, awareness of the signs and symptoms (S/S) of thin versus intermediate or deep melanoma may be helpful in guiding management. The authors performed a prospective evaluation of the S/S reported by patients who presented at Memorial Sloan‐Kettering Cancer Center with invasive primary melanoma.

METHODS

The authors prospectively evaluated 369 patients with a detailed questionnaire regarding their S/S at the time of their initial visit. Multivariate logistic regression was employed to study the association between S/S reported by the patient and Breslow depth of the primary lesion, adjusting for gender, age, and anatomic site. Patients were grouped by the Breslow depth of their primary tumors into three categories for analysis: those with thin (≤ 1.0 mm), intermediate (1.0–4.0 mm), and thick (≥ 4.0 mm) lesions.

RESULTS

Gender, age, and primary site were not significantly predictive of increasing category of Breslow depth. Most patients reported at least one S/S (n= 278 [75%]). The most common S/S reported was an increase in size (n= 187 [51%]), followed by a change in color (n= 147 [40%]). Bleeding (n= 95 [26%]), lump (n= 86 [23%]), itching (n= 83 [22%]), skin breakdown (n= 66 [18%]), and pain (n= 24 [7%]) were less common. In a multivariate analysis, the S/S most strongly associated with an increased category of Breslow depth was bleeding (odds ratio [OR] 7.5), followed by pain (OR 3.3), lump (OR 2.2), itching (OR 1.9), and change in size (OR 1.7). The only S/Ss not independently associated with an increasing category of Breslow depth were a change in color and skin breakdown. The presence of one or more S/S was associated significantly with an increased category of Breslow depth of the primary melanoma (1 or 2 S/S vs. no S/S: OR, 4; ≥ 3 S/S vs. no S/S: OR, 24).

CONCLUSION

Most S/Ss of cutaneous melanoma are associated with an increasing risk of a deep primary lesion. Understanding this relationship can be valuable in patient management, especially when pathologic data are incomplete or inconsistent with the patient's history. Cancer 2003;98:344–8. © 2003 American Cancer Society.

DOI 10.1002/cncr.11513
Targeted filgrastim support in patients with early‐stage breast carcinoma
Authors: Rivera Edgardo , Erder M. Haim , Moore Timothy D. , Shiftan Thomas L. , Knight Chris A. , Fridman Moshe , Brannan Carol , Danel‐Moore Laurence , Hortobagyi Gabriel N. ,   for the Risk Model Study Group
Published: July 2003

BACKGROUND

Severe neutropenia, a common consequence of chemotherapy, may result in infectious complications and hospitalizations. Preventive treatment with colony‐stimulating factors is limited because of the inability to predict which patients will develop neutropenic complications. To the authors' knowledge, the current study is the first large prospective validation of a risk model in patients with early‐stage breast carcinoma.

METHODS

Patients with Stage I–III breast carcinoma who were receiving adjuvant chemotherapy (n = 624) were assigned to risk groups based on first‐cycle absolute neutrophil count (ANC) nadirs of < 0.5 × 109/L. Filgrastim (a recombinant human granulocyte–colony‐stimulating factor) was administered from Cycle 2 onward to high‐risk patients. Dose intensity and rates of neutropenic complications, including febrile neutropenia and hospitalization resulting from it, were calculated for each group and compared. High‐risk patients were matched by chemotherapy regimen, stage of disease, age, and baseline ANC to historic‐control patients and outcomes were compared within the matched pairs.

RESULTS

Both risk groups were found to have a similar proportion of patients receiving > 85% of the dose intensity (95.8% vs. 94.4%). The rate of febrile neutropenia and hospitalization in the low‐risk group (n = 264) was 2.6% (95% confidence interval [95% CI[], 0.7–4.5%) and 0.8 (95% CI, ‐0.3–1.9%), respectively. The high‐risk group was 2.6 times more likely to receive a full dose of chemotherapy, but no higher risk of neutropenic complications was reported compared with the matched controls.

CONCLUSIONS

The risk‐related prophylactic administration of filgrastim facilitated the delivery of planned chemotherapy to the high‐risk group of patients. However, further research is needed to confirm the results obtained in the current study in a randomized trial, if feasible, and in other chemotherapy and disease settings. Cancer 2003;98:222–8. © 2003 American Cancer Society.

DOI 10.1002/cncr.11516
High‐dose 131I‐metaiodobenzylguanidine therapy for 12 patients with malignant pheochromocytoma
Authors: Rose Brian , Matthay Katherine K. , Price David , Huberty John , Klencke Barbara , Norton Jeffrey A. , Fitzgerald Paul A.
Published: July 2003

BACKGROUND

131I‐Metaiodobenzylguanidine (131I‐MIBG) can be used systemically to treat malignant pheochromocytoma. To improve outcome, the authors used higher levels of activity of 131I‐MIBG than previously reported. The authors reported the response rates and toxicity levels in patients with malignant pheochromocytoma or paraganglioma who were treated with high‐dose 131I‐MIBG.

METHODS

Following debulking surgery and stem cell harvest, 12 patients with malignant pheochromocytoma or paraganglioma were treated with 131I‐MIBG. Five had received previous external beam radiation and/or chemotherapy. The median single treatment dose was 800 mCi (37 gigabecquerels; range, 386–866 mCi) or 11.5 mCi/kg (range, 5.6–18.3 mCi/kg). The median cumulative dose was 1015 mCi (range, 386–1690 mCi).

RESULTS

Three patients had a complete response, two of whom had soft tissue and skeletal metastases. Their median follow‐up was 45 months (range, 23–101 months). Seven patients had a partial response (PR), with a median follow‐up 43 months (range, 6–47 months). Two patients without a response died with progressive disease (PD) and 2 patients with an initial PR died of PD at 13 and 11 months, respectively. Grade 3 thrombocytopenia occurred after 79% (15 of 19) of treatments had been administered. Grade 3 and 4 neutropenia followed 53% (10 of 19) and 19% (4 of 19) of treatments, respectively. One patient required stem cell infusion, and one developed primary ovarian failure.

CONCLUSIONS

The single and cumulative doses of 131I‐MIBG were approximately 2–3.5 times higher than those used at other centers. Unlike previous reports, two patients with both skeletal and soft tissue metastases had a complete response. Hematologic toxicity was significant but tolerable. High‐dose 131I‐MIBG may lead to long‐term survival in patients with malignant pheochromocytoma. Cancer 2003;98:239–48. © 2003 American Cancer Society.

DOI 10.1002/cncr.11518
18‐Fluoro‐2‐deoxyglucose positron emission tomography in detecting residual/recurrent nasopharyngeal carcinomas and comparison with magnetic resonance imaging
Authors: Yen Ruoh‐Fang , Hung Rey‐Long , Pan Mei‐Hsiu , Wang Yao‐Hung , Huang Kou‐Mou , Lui Louis T. , Kao Chia‐Hung
Published: July 2003

BACKGROUND

It is known that 18‐fluoro‐2‐deoxyglucose positron emission tomography (FDG‐PET) is effective in the early detection of residual/recurrent nasopharyngeal carcinomas (NPC). To compare FDG‐PET with the conventional magnetic resonance imaging (MRI) for the detection of residual/recurrent NPC, the authors studied 67 follow‐up cases of patients with NPC using both FDG‐PET and MRI.

METHODS

From February 1997 to February 2001, 67 NPC patients (14 women, 53 men; age range, 16–67 years; mean age, 46.6 ± 12.5 years) were recruited. Both FDG‐PET and MRI of the head and neck area for each patient were performed at least 4 months (duration range, 4–70 months; mean, 14 ± 13.5 months) after radiotherapy or radiotherapy with concurrent chemotherapy. The final diagnosis was confirmed by biopsy or clinical follow‐up for at least 6 months.

RESULTS

The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of FDG‐PET images were 100%, 93.4%, 95.5%, 87.5%, and 100%, respectively. In contrast, the sensitivity, specificity, accuracy, PPV, and NPV of the MRI scans were 61.9%, 43.5%, 49.3%, 33.3%, and 70.0%, respectively.

CONCLUSIONS

The results of the current study suggest that FDG‐PET is much more effective than MRI in detecting residual/recurrent NPC. Cancer 2003;98:283–7. © 2003 American Cancer Society.

DOI 10.1002/cncr.11519
Neuroblastoma in adolescents
Authors: Gaspar Nathalie , Hartmann Olivier , Munzer Caroline , Bergeron Christophe , Millot Frédéric , Cousin‐Lafay Lucie , Babin‐Boilletot Annie , Blouin Pascale , Pajot Christine , Coze Carole
Published: July 2003

BACKGROUND

Less than 5% of neuroblastomas are diagnosed in adolescent patients. Previous studies of patients who were treated with less intensive chemotherapy regimens relative to currently available regimens suggested that adolescents survived longer than younger children, and this finding was related to a lack of myc‐N amplification. Those reports prompted the authors to study a cohort of adolescent patients who had been included in more recent trials.

METHODS

The authors investigated the presentation, treatment, and outcome in 28 adolescent patients who were enrolled in studies of the French Society of Pediatric Oncology during the period from 1987 to 1999 and who were older than age 10 years at the time they were diagnosed with neuroblastoma. The results were used to compare this subpopulation with a control group of children.

RESULTS

None of the six patients with Stage I–II disease either developed recurrent disease or died. At 5 years, disease progression was high (progression‐free survival [PFS], 28%) for the 9 adolescents with Stage III disease, but so was survival (overall survival [OS], 86%). The 13 adolescent patients with metastatic neuroblastoma had very poor outcomes (PFS, 18%; OS, 27%). Despite intensive therapy, advanced neuroblastoma appeared to carry a poorer prognosis in adolescent patients compared with children, although patients with Stage III disease had a more indolent course. No difference was found between adolescent patients and children regarding the clinical presentation, treatment schedule, or doses and tolerance of chemotherapy. The incidence of elevated urinary catecholamine metabolite secretion was lower in adolescents compared with children.

CONCLUSIONS

Adolescent patients with advanced neuroblastoma had less favorable outcomes compared with children, even if survival in adolescents with Stage III disease seemed longer. Cancer 2003;98:349–55. © 2003 American Cancer Society.

DOI 10.1002/cncr.11521
Brain metastasis from prostate carcinoma
Authors: Tremont‐Lukats Ivo W. , Bobustuc George , Lagos George K. , Lolas Konstantinos , Kyritsis Athanassios P. , Puduvalli Vinay K.
Published: July 2003

BACKGROUND

The objective of this study was to estimate the incidence and describe distribution, clinical presentation, and prognosis of brain metastases in patients with prostrate carcinoma who were seen at The University of Texas M. D. Anderson Cancer Center (MDACC).

METHODS

The authors reviewed the charts of 16,280 patients with prostate carcinoma in the MDACC patient data base. Of 131 patients with craniospinal metastases confirmed by neuroimaging (n = 53 patients) or autopsy (n = 78 patients), 103 of 16,280 patients (0.63%) had parenchymal metastases.

RESULTS

The median patient age at diagnosis was 64 years (range, 16–85 years). The median interval from the diagnosis of prostate carcinoma to the detection of brain metastasis was 35 months for patients with adenocarcinoma and 48 months for patients with small cell carcinoma (SCC). Confusion, headache, and memory deficits were the most frequent initial symptoms. Eighty‐six percent of patients had single lesions, and 14% of patients had ≥ 2 lesions. Metastases were supratentorial in 81 of 103 patients (76%), infratentorial in 22 of 103 patients (21%), and both supratentorial and infratentorial in 3 of 103 patients (3%). SCC and cribriform subtypes were more likely than adenocarcinoma to metastasize to the brain (relative risk, 20.36; 95% confidence interval, 9.91–41.84). Regardless of histology, the median survival in untreated patients was 1 month compared with 3.5 months in patients who were treated with radiotherapy. Patients who underwent stereotactic radiosurgery (n = 5 patients) had a longer median survival (9 months). Survival was not affected by supratentorial or infratentorial location of metastases.

CONCLUSIONS

Brain metastasis from prostate carcinoma is a rare, terminal event with death in < 1 year frequently due to advanced, systemic disease. The majority of metastases were single and supratentorial. The most common clinical presentation was nonfocal neurologic symptoms related to intracranial hypertension. A better understanding of the biology of prostate carcinoma will help clarify the basis for its metastasis to the brain. Cancer 2003;98:363–8. © 2003 American Cancer Society.

DOI 10.1002/cncr.11522
Improved radiation protection of the thyroid gland with thyroxine, methimazole, and potassium iodide during diagnostic and therapeutic use of radiolabeled metaiodobenzylguanidine in children with neuroblastoma
Authors: van Santen Hanneke M. , de Kraker Jan , van Eck Berthe L. F. , de Vijlder Jan J. M. , Vulsma Thomas
Published: July 2003

BACKGROUND

During radiolabeled metaiodobenzylguanidine (MIBG) administration in children with neuroblastoma, the thyroid is protected from 123/131I uptake by potassium iodide. Despite this protection, up to 64% of patients develop thyroid dysfunction. The authors introduce a new method of radiation protection for the thyroid gland.

METHODS

In a prospective cohort study, 34 children with neuroblastoma who received MIBG were given thyroxine, methimazole, and potassium iodide for protection of the thyroid gland. Protection started 1 day before the start of diagnostic 123I‐MIBG and was continued until 4 weeks after the last therapeutic 131I‐MIBG dose. Follow‐up measurements were performed every 3 months after the protection was stopped. Visualization of the thyroid on MIBG images was reviewed by three nuclear medicine physicians. Results were compared with a historic control group of children who had received potassium iodide for thyroid protection during MIBG administration.

RESULTS

After a mean follow‐up of 19 months, there were 23 evaluable patients. Thyroid function was normal in 86% of survivors compared with 44% of children in the historic control group (P = 0.011; Pearson chi‐square test). Scintigraphic visualization of the thyroid diminished substantially after the new protection (21.5% vs. 5.3%, respectively; P = 0.000).

CONCLUSIONS

The results of the current study indicate that compared with potassium iodide alone, combined thyroxine, methimazole, and potassium iodide protect the thyroid more effectively against radiation damage from 123/131I during diagnostic and therapeutic MIBG administration in children with neuroblastoma. Cancer 2003;98:389–96. © 2003 American Cancer Society.

DOI 10.1002/cncr.11523
Potential conflict between fundamental ethical principles and requirements of the oncology drug approval process
Authors: Markman Maurie , DeMarco Joseph
Published: July 2003

DOI 10.1002/cncr.11566
Numerical representation of the quality measures of triangles and triangular meshes
Authors: Sarrate J. , Palau J. , Huerta A.
Published: July 2003

In this note a new procedure to represent the quality measure for triangles is proposed. The triangles are identified by their three angles and are represented in a bounded domain, called angle representation region, according to the area co‐ordinates, which are common and well known by finite element users. The developed representation can also be used in order to visualize the characteristics of any quality measure. This new procedure is extended to graphically represent triangular meshes in the angle representation region. Copyright © 2003 John Wiley & Sons, Ltd.
Interpolation requirements for implicit gradient‐enhanced continuum damage models
Authors: Simone A. , Askes H. , Peerlings R. H. J. , Sluys L. J.
Published: July 2003

Some properties of a gradient‐enhanced continuum damage model were discussed by means of a numerical and theoretical study. In particular, it is demonstrated that the discretization of this model does not belong to the class of mixed finite element formulations (although the model has the format of a general coupled problem). Hence, the Babuška–Brezzi condition does not apply to this type of models. Consequently, the use of linear interpolation functions for displacements as well for non‐local equivalent strains yields excellent performance in terms of rate of convergence and of convergence of the numerical procedure. Copyright © 2003 John Wiley & Sons, Ltd.
Error estimates in 2‐node shear‐flexible beam elements
Authors: Singh Gajbir , Venkateswara Rao G.
Published: July 2003

The objective of the paper is to report the investigation of error estimates/or convergence characteristics of shear‐flexible beam elements. The order and magnitude of principal discretization error in the usage of various types beam elements such as: (a) 2‐node standard isoparametric element, (b) 2‐node field‐consistent/reduced integration element and (c) 2‐node coupled‐displacement field element, is assessed herein. The method employs classical order of error analyses that is commonly used to evaluate the discretization error of finite difference methods. The finite element equilibrium equations at any node are expressed in terms of differential equations through the use of Taylor series. These differential equations are compared with the governing equations and error terms are identified. It is shown that the discretization error in coupled‐field elements is the least compared to the field‐consistent and standard finite elements (based on exact integration). Copyright © 2003 John Wiley & Sons, Ltd.
Homogenization technique for transient heat transfer in unidirectional composites
Authors: Kamiński Marcin
Published: July 2003

The article presented is devoted to the homogenization of transient heat transfer problems in unidirectional composites. Mathematical model is based on the effective modules method applied to unidirectional periodic composites—the effective heat conductivity is calculated in the closed form; the effective volumetric heat capacity for the entire composite is obtained by simple spatial averaging. Such a homogenization scheme makes it possible to significantly simplify numerical analysis of transient heat phenomena in various types of unidirectional composites with complicated microgeometry. The comparison of transient heat transfer problem for the composite in real and homogenized configuration is carried out using a specially adopted finite element method computer program. Copyright © 2003 John Wiley & Sons, Ltd.
Effects of chemical reaction, heat and mass transfer on non‐linear MHD flow over an accelerating surface with heat source and thermal stratification in the presence of suction or injection
Authors: Anjali Devi S. P. , Kandasamy R.
Published: July 2003

An approximate numerical solution for the steady MHD laminar boundary‐layer flow over an accelerating vertical surface with suction or injection in the presence of species concentration and mass diffusion has been obtained by solving the governing equations using R.K. Gill method. The fluid is assumed to be viscous, incompressible and electrically conducting with a magnetic field applied transversely to the direction of the flow. It has been observed that in the presence of mass diffusion: (i) in the case of suction, the velocity decreases and the temperature distribution and concentration of the fluid increase and for injection, the velocity increases and the temperature distribution and concentration of the fluid decrease with increase of thermal stratification parameter, (ii) in the presence of thermal stratification parameter in both the cases of suction and injection, the skin friction and rate of mass transfer decrease and the rate of heat transfer of the fluid increases with increase of chemical reaction effects, (iii) in the cases of suction and injection, an increase in the strength of magnetic field leads to fall in the velocity and rise in the temperature and concentration of the fluid along the surface. Copyright © 2003 John Wiley & Sons, Ltd.
An endochronic plasticity model for numerical simulation of industrial powder compaction processes
Authors: Khoei A. R. , Bakhshiani A. , Mofid M.
Published: July 2003

In this paper, the numerical modelling of powder forming process is simulated by a finite element analysis using an endochronic plasticity model. A general algorithm for the endochronic theory from the viewpoint of efficient numerical modelling is presented. Constitutive equations are established based on coupling between deviatoric and hydrostatic behaviour to the endochronic theory. Finally, the numerical schemes are examined for efficiency in the modelling of a rotational flanged‐component. It is shown how the endochronic plasticity describes the behaviour of powder material from the initial stage of compaction to final stage, in which material behaves as solid metals. Copyright © 2003 John Wiley & Sons, Ltd.
Analysis of a projection/characteristic scheme for incompressible flow
Authors: Guermond Jean‐Luc , Minev Peter D.
Published: July 2003

The paper presents the convergence analysis of a characteristic/projection scheme for the incompressible Navier–Stokes equations. This scheme is a modification of the scheme analysed in Achdou and Guermond (SIAM J. Numer. Anal. 2000; 37(3):799) which does not eliminate the projected velocity field from the system but rather uses it as the advecting field in the explicit characteristic advection. This field has a zero (generalized) divergence and is therefore more suitable for this purpose. It appears that this scheme has the same convergence rate as the one in Achdou and Guermond (SIAM J. Numer. Anal. 2000; 37(3):799) but on a given grid seems to produce more accurate results. The computational cost is not significantly higher since it requires only one extra inversion of the mass matrix which can be done relatively efficiently. We present numerical results which illustrate the properties of the scheme. Copyright © 2003 John Wiley & Sons, Ltd.
Modelling damage potential of high‐frequency ground motions
Authors: Ma Guowei , Hao Hong , Lu Yong
Published: July 2003

Damage to building structures due to underground blast‐induced ground motions is a primary concern in the corresponding determination of the safe inhabited building distance (IBD). Because of the high‐frequency nature of this category of ground motions and especially the presence of significant vertical component, the characteristics of structural response and damage differ from those under seismic type low‐frequency ground motions. This paper presents a numerical investigation aimed at evaluating reinforced concrete (RC) structure damage generated by underground blast‐induced ground excitation. In the numerical model, two damage indices are proposed to model reinforced concrete failure. A fracture indicator is defined to track the cracking status of concrete from micro‐ to macrolevel; the development of a plastic hinge due to reinforcement yielding is monitored by a plastic indicator; while the global damage of the entire structure is correlated to structural stiffness degradation represented by its natural frequency reduction. The proposed damage indices are calibrated by a shaking table test on a 1: 5‐scale frame model. They are then applied to analyse the structural damage to typical low‐ to high‐rise RC frames under blast‐induced ground motions. Results demonstrate a distinctive pattern of structural damage and it is shown that the conventional damage assessment methods adopted in seismic analysis are not applicable here. It is also found that the existing code regulation on allowable peak particle velocity of blast‐induced ground motions concerning major structural damage is very conservative for modern RC structures. Copyright © 2003 John Wiley & Sons, Ltd.
Efficiency of base isolation systems in structural seismic protection and energetic assessment
Authors: Marano Giuseppe Carlo , Greco Rita
Published: July 2003

This paper concerns the seismic response of structures isolated at the base by means of High Damping Rubber Bearings (HDRB). The analysis is performed by using a stochastic approach, and a Gaussian zero mean filtered non‐stationary stochastic process is used in order to model the seismic acceleration acting at the base of the structure. More precisely, the generalized Kanai–Tajimi model is adopted to describe the non‐stationary amplitude and frequency characteristics of the seismic motion.

The hysteretic differential Bouc–Wen model (BWM) is adopted in order to take into account the non‐linear constitutive behaviour both of the base isolation device and of the structure. Moreover, the stochastic linearization method in the time domain is adopted to estimate the statistical moments of the non‐linear system response in the state space. The non‐linear differential equation of the response covariance matrix is then solved by using an iterative procedure which updates the coefficients of the equivalent linear system at each step and searches for the solution of the response covariance matrix equation.

After the system response variance is estimated, a sensitivity analysis is carried out. The final aim of the research is to assess the real capacity of base isolation devices in order to protect the structures from seismic actions, by avoiding a non‐linear response, with associated large plastic displacements and, therefore, by limiting related damage phenomena in structural and non‐structural elements.

In order to attain this objective the stochastic response of a non‐linear n‐dof shear‐type base‐isolated building is analysed; the constitutive law both of the structure and of the base devices is described, as previously reported, by adopting the BWM and by using appropriate parameters for this model, able to suitably characterize an ordinary building and the base isolators considered in the study.

The protection level offered to the structure by the base isolators is then assessed by evaluating the reduction both of the displacement response and the hysteretic dissipated energy. Copyright © 2003 John Wiley & Sons, Ltd.
System identification of linear structures based on Hilbert–Huang spectral analysis. Part 2: Complex modes
Authors: Yang Jann N. , Lei Ying , Pan Shuwen , Huang Norden
Published: July 2003

A method, based on the Hilbert–Huang spectral analysis, has been proposed by the authors to identify linear structures in which normal modes exist (i.e., real eigenvalues and eigenvectors). Frequently, all the eigenvalues and eigenvectors of linear structures are complex. In this paper, the method is extended further to identify general linear structures with complex modes using the free vibration response data polluted by noise. Measured response signals are first decomposed into modal responses using the method of Empirical Mode Decomposition with intermittency criteria. Each modal response contains the contribution of a complex conjugate pair of modes with a unique frequency and a damping ratio. Then, each modal response is decomposed in the frequency–time domain to yield instantaneous phase angle and amplitude using the Hilbert transform. Based on a single measurement of the impulse response time history at one appropriate location, the complex eigenvalues of the linear structure can be identified using a simple analysis procedure. When the response time histories are measured at all locations, the proposed methodology is capable of identifying the complex mode shapes as well as the mass, damping and stiffness matrices of the structure. The effectiveness and accuracy of the method presented are illustrated through numerical simulations. It is demonstrated that dynamic characteristics of linear structures with complex modes can be identified effectively using the proposed method. Copyright © 2003 John Wiley & Sons, Ltd.
Response of structures supported on SCF isolation systems
Authors: Hamidi M. , El Naggar M. H. , Vafai A.
Published: July 2003

Aseismic base isolation is an effective method used to protect structures and their contents against earthquakes. An isolated structure may be designed to remain elastic throughout major ground motions as a result of the efficiency of the isolation systems. In this paper, the equations of motion of two‐dimensional elastic structures supported on a new base isolation system called the Sliding Concave Foundation (SCF) are presented and a procedure for their solution is suggested. The responses of a number of structures subjected to different earthquake records are evaluated and the results are compared with those of the same structures supported on two other famous isolation systems and also a fixed base condition. The results indicate the effectiveness of the SCF in protecting the supported structures even during very strong and/or long period earthquakes. Copyright © 2003 John Wiley & Sons, Ltd.
Evaluation of combination rules for peak response calculation in three‐component seismic analysis
Authors: Hernández Julio J. , López Oscar A.
Published: July 2003

The responses, re, given by several multicomponent combination rules used in seismic codes for determining peak responses to three ground motion components are evaluated for elastic systems and compared with the critical response rcr; this is defined as the largest response for all possible incident angles of the seismic components and obtained by means of the CQC3‐rule when a principal seismic component is vertical, or the GCQC3‐rule when it departs from the vertical direction. The combination rules examined are the SRSS‐, 30%‐, 40%‐ and IBC‐rules, considering different alternatives for the design horizontal spectrum.

Assuming that a principal seismic component is along the vertical direction, the upper and lower bounds of the ratio re/rcr for each combination rule are determined as a function of the spectral intensity ratio of the horizontal seismic components and of the responses to one seismic component acting alternately along each structural axis. Underestimations and overestimations of the critical response are identified for each combination rule and each design spectrum. When a component departs from the vertical direction, the envelopes of the bounds of the ratio re/rcr for each combination rule are calculated, considering all possible values of the spectral intensity ratios. It is shown that the inclination of a principal component with respect to the vertical axis can significantly reduce the values of re/rcr with respect to the case when the component is vertical. Copyright © 2003 John Wiley & Sons, Ltd.
A simplified method of constructing fragility curves for highway bridges
Authors: Karim Kazi R. , Yamazaki Fumio
Published: July 2003

Fragility curves are found to be useful tools for predicting the extent of probable damage. They show the probability of highway structure damage as a function of strong motion parameters, and they allow the estimation of a level of damage probability for a known ground motion index. In this study, an analytical approach was adopted to develop the fragility curves for highway bridges based on numerical simulation. Four typical RC bridge piers and two RC bridge structures were considered, of which one was a non‐isolated system and the other was an isolated system, and they were designed according to the seismic design code in Japan. From a total of 250 strong motion records, selected from Japan, the United States, and Taiwan, non‐linear time history analyses were performed, and the damage indices for the bridge structures were obtained. Using the damage indices and ground motion parameters, fragility curves for the four bridge piers and the two bridge structures were constructed assuming a lognormal distribution. It was found that there was a significant effect on the fragility curves due to the variation of structural parameters. The relationship between the fragility curve parameters and the over‐strength ratio of the structures was also obtained by performing a linear regression analysis. It was observed that the fragility curve parameters showed a strong correlation with the over‐strength ratio of the structures. Based on the observed correlation between the fragility curve parameters and the over‐strength ratio of the structures, a simplified method was developed to construct the fragility curves for highway bridges using 30 non‐isolated bridge models. The simplified method may be a very useful tool to construct the fragility curves for non‐isolated highway bridges in Japan, which fall within the same group and have similar characteristics. Copyright © 2003 John Wiley & Sons, Ltd.
Active tuned liquid column damper with propellers
Authors: Chen Yung‐Hsiang , Ko Chia‐Hao
Published: July 2003

The active control of a Tuned Liquid Column Damper (TLCD) with two propellers is presented. A single‐degree‐of‐freedom system with a passive or active TLCD is used as an example to set up the basic equation of motion. The Optimal Control Theory is applied to establish the control law and to calculate the control force generated by these two propellers installed inside the TLCD. A simple pendulum‐like model test is carried out to study the dynamic characteristics of the passive and active TLCDs and the effectiveness of the vibrational control. Comparison of the experimental result with the analytical one shows a good agreement. Finally, the analytical results of the seismic response are also included as an example for demonstration and application. Copyright © 2003 John Wiley & Sons, Ltd.
Large earthquakes and the abandonment of prehistoric coastal settlements in 15th century New Zealand
Authors: Goff James R. , McFadgen Bruce G.
Published: July 2003

This paper reports on the effects of large earthquakes and related events, such as tsunamis, on prehistoric coastal settlements in New Zealand. It is based on field observations at several well‐established archaeological sites around the Cook Strait region and on literature reviews. We identify three broad periods of seismic activity in New Zealand since human occupation of the islands: 13th century, 15th century, and the 1750s to 1850s. The most significant, from a prehistoric human perspective, is the 15th century. Using examples from the Cook Strait region, we suggest that the abandonment of coastal settlements, the movement of people from the coast to inland areas, and a shift in settlement location from sheltered coastal bays to exposed headlands, was due to seismic activity, including tsunamis. We expect similar patterns to have occurred in other parts of New Zealand, and other coastal areas of the world with longer occupation histories. © 2003 Wiley Periodicals, Inc.
Depositional history and evolution of the Paso del Indio site, Vega Baja, Puerto Rico
Authors: Clark Jeffrey J. , Walker Jeff , Ramos Reniel Rodríguez
Published: July 2003

Potshards discovered during excavation of bridge pilasters for a major expressway over the Rio Indio floodplain, a stream incised within the karsts of north‐central Puerto Rico, required large‐scale archaeological excavation. Five‐meter‐deep bridge pilaster excavations in the alluvial valley provide a 4500‐year history of deposition. Stratigraphic analysis of the exposed pilaster walls in combination with textural and organic carbon analyses of sediment cores obtained over a much broader area suggest a fluvial system dominated by overbank deposition. Six sequences of alternating light and dark layers of sediment were identified. The darker layers are largely composed of silts and clays, whereas the lighter layers are rich in sand‐sized sediment. Archaeological evidence indicates the organic‐rich dark layers, believed to be buried A horizons, coincide with pre‐historic occupation by Cedrosan Saladoid, Elenan Ostionoid, and Chican Ostionoid, extending from A.D. 450 to A.D. 1500. Lighter layers below the dark soil horizons are interpreted as overbank deposits from large magnitude flood events. The floodplain aggraded discontinuously with rapid deposition of sand followed by gradual accumulation of silt, clay, and organic material. An approximately 1‐m‐thick layer of coarse sand and gravel halfway up the stratigraphic column represents an episode of more frequent and severe floods. Based on radiocarbon ages, this layer aggraded between A.D. 1000 and A.D. 1100, which is well within the Elenan Ostionoid era (A.D. 900–1200). Rates of sedimentation during this period were approximately 8 mm per year, ten times greater than the estimates of sedimentation rates before and after this flood sequence. The cause for the change in deposition is unknown. Nonetheless the Elenan Ostionoid would have had to endure frequent loss of habitation structures and crops during these events. © 2003 Wiley Periodicals, Inc.
Geoarchaeological investigations at Studenoe, an Upper Paleolithic site in the Transbaikal Region, Russia
Authors: Buvit Ian , Waters Michael R. , Konstantinov Mikhail V. , Konstantinov Aleksander V.
Published: July 2003

In 1998, geoarchaeological research was carried out at the Upper Paleolithic site of Studenoe in the Transbaikal Region of Russia. The site is divided into three loci situated on two terraces overlooking the Chikoi River. Alluvial sediments beneath the oldest terrace (T2) consist of two depositional units. Radiocarbon ages indicate that aggradation of the T2 fill began before 18,000 yr B.P. Alluvial sediments beneath the lower terrace (T1) range in age from 13,000 to 10,000 yr B.P. and are divided into three depositional units. Both terraces are overlain by Holocene colluvium. Archaeological materials at Studenoe 1/1, 1/2, and 2 include dwellings, hearths, and thousands of bone and stone artifacts assigned to the late Upper Paleolithic through the Bronze Age. Evidence of microblade technology is present in all components of the site. Material from recent excavations of Paleolithic levels in the T2 fill at Studenoe includes mobiliary art, bone needles, and a large dwelling with four hearth features. © 2003 Wiley Periodicals, Inc.
Theoretical studies on structures and reactivities of organocuprate(I) and organocopper(III) species
Authors: Yamanaka Masahiro , Inagaki Akiko , Nakamura Eiichi
Published: July 2003

Systematic evaluation of method and basis set on the structure and energetics of organocuprate(I) and organocopper(III) species has been carried out. Various structures of organocuprate(I) and organocuprate(III) complexes were optimized with the HF, MP2, and B3LYP methods, and compared with the structures determined by X‐ray crystallography (i.e., Me2Cu(I)−, (CF3)4Cu(III)−). Both the MP2 and B3LYP methods reasonably reproduce the X‐ray structures while the HF method does not. Using larger basis set and incorporating the relativistic effects for Cu afford the best results. In the studies on the energetics of a LiCu cluster model (Me2CuLi · LiCl) and Me3Cu model with the MP2, MP3, MP4DQ, MP4SDQ, CCSD(T), and B3LYP methods, the B3LYP method gives energetics similar to those obtained with the CCSD(T) method with much less cost, and hence, is judged to be the best practical method. The studies have shown that B3LYP method with the basis set incorporating the relativistic effective core potentials for Cu and the 6‐31G* basis set for the rest is the theoretical method that is the most cost‐effective for the studies of the structure and energetics of organocuprate(I) and organocopper(III) species. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1401–1409, 2003
Improved precision and efficiency of free energy calculations for small systems using λ‐scaled atomic masses and separating conformational and transformational sampling
Authors: Carlsson Peter , Nilsson Lennart
Published: July 2003

We present results showing the importance of appropriate treatment of atomic masses in molecular dynamics (MD)‐based single topology free‐energy perturbations (FEPs) on small molecule systems. The reversibility of gas phase simulations is significantly improved by scaling the atomic mass of mutated atoms with the λ variable normally used for the scaling of energy terms. Because this effect is less pronounced for solvated systems, it will not cancel in estimates of the relative hydration free energy difference. The advantage of mass scaling is demonstrated by a null mutation of ethane to ethane and the calculation of the relative hydration free energy difference between ethane and n‐propane. Furthermore, it is found that the simulation time necessary for converged MD/FEPs is prohibitively large for relative hydration free energy calculations on cyclic alkanes. Therefore, we explore an alternative free energy pathway including strongly constrained conformations to improve convergence in FEP simulations of flexible molecules. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1383–1389, 2003
Exploring potential energy surfaces for chemical reactions: An overview of some practical methods
Authors: Schlegel H. Bernhard
Published: July 2003

Potential energy surfaces form a central concept in the application of electronic structure methods to the study of molecular structures, properties, and reactivities. Recent advances in tools for exploring potential energy surfaces are surveyed. Methods for geometry optimization of equilibrium structures, searching for transition states, following reaction paths and ab initio molecular dynamics are discussed. For geometry optimization, topics include methods for large molecules, QM/MM calculations, and simultaneous optimization of the wave function and the geometry. Path optimization methods and dynamics based techniques for transition state searching and reaction path following are outlined. Developments in the calculation of ab initio classical trajectories in the Born‐Oppenheimer and Car‐Parrinello approaches are described. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1514–1527, 2003
Alcohols, ethers, carbohydrates, and related compounds. I. The MM4 force field for simple compounds
Authors: Allinger Norman L. , Chen Kuo‐Hsiang , Lii Jenn‐Huei , Durkin Kathleen A.
Published: July 2003

Simple alcohols and ethers have been studied with the MM4 force field. The structures of 13 molecules have been well fit using the MM4 force field. Moments of inertia have been fit with rms percentage errors as indicated: 18 moments for ethers, 0.28%; 21 moments for alcohols, 0.22%. Rotational barriers and conformational equilibria have also been examined, and the experimental and ab initio results are reproduced substantially better with MM4 than they were with MM3. Much of the improvement comes from the use of additional interaction terms in the force constant matrix, of which the torsion–bend and torsion–torsion are particularly important. Induced dipoles are included in the calculation, and dipole moments are reasonably well fit. It has been possible for the first time to fit conformational energetic data for both open chain and cyclic alcohols (e.g., propanol and cyclohexanol) with the same parameter set. For vibrational spectra, over a total of 82 frequencies, the rms error is 27 cm−1, as opposed to 38 cm−1 with MM3. Both the α and β bond shortening resulting from the presence of the electronegative oxygen atom in the molecule are well reproduced. The electronegativity of the oxygen is sufficient that one must also include not only the α and β electronegativity effects on bond lengths, but also on angle distortions, if structures are to be well reproduced. The heats of formation of 32 alcohols and ethers were fit overall to within experimental error (weighted standard deviation error 0.26 kcal/mol). © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1447–1472, 2003
Alcohols, ethers, carbohydrates, and related compounds. II. The anomeric effect
Authors: Lii Jenn‐Huei , Chen Kuo‐Hsiang , Durkin Kathleen A. , Allinger Norman L.
Published: July 2003

The anomeric effect has been studied for a variety of compounds using the MM4 force field, and also using MP2/6‐311++G(2d,2p) ab initio calculations and experimental data for reference purposes. Geometries and energies, including conformational, rotational barriers, and heats of formation were examined. Overall, the agreement of MM4 with the experimental and ab initio data is good, and significantly better than the agreement obtained with the MM3 force field. The anomeric effect is represented in MM4 by various explicit terms in the force constant matrix. The bond length changes are accounted for with torsion‐stretch elements. The angle changes are accounted for with torsion‐bend elements. The energies are taken into account with a number of torsional terms in the usual way. A torsion‐torsion interaction is also of some importance. With all of these elements included in the calculation, the MM4 results now appear to be adequately accurate. The heats of formation were examined for a total of 12 anomeric compounds, and the experimental values were fit by MM4 with an RMS error of 0.42 kcal/mol. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1473–1489, 2003
Alcohols, ethers, carbohydrates, and related compounds. III. The 1,2‐dimethoxyethane system
Authors: Lii Jenn‐Huei , Chen Kuo‐Hsiang , Grindley T. Bruce , Allinger Norman L.
Published: July 2003

Ethylene glycol, its dimethyl ether, and some related compounds have been studied using the MM4 molecular mechanics force field. The MM4 calculated structural and energetic results have been brought into satisfactory agreement with a considerable number of experimental data and MP2/6‐311++G(2d,2p) ab initio calculations. The heats of formation of these compounds are also well calculated. The MM4 ethylene glycol conformations in particular are in good agreement, both geometrically and in terms of energy, with those from the ab initio calculations. The corresponding dimethyl ether is of special interest, because it has been suggested that the trans‐gauche conformation is unusually stable due to the hydrogen bonding of a hydrogen on a methyl group with the more distant oxygen. It is shown in the present work that while this conformation is more stable than might have been expected, the energy is adequately calculated by MM4 without using any hydrogen bonding between the CH bond and the oxygen. If such hydrogen bonding occurs, it amounts to no more than about 0.5 kcal/mol in energy, and is too small to detect with certainty. Additionally, energetic relationships in trans‐1,2‐dimethoxycyclohexane, 1,3,5,7‐tetraoxadecalin, and 3‐methoxytetrahydropyran have been studied, and the calculated results are compared with experimental information, which is adequately reproduced. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1490–1503, 2003