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In this work, a new high accuracy solution for vibrations of structures made of plate segments is presented. Each plate segment is deforming both in and out of its plane, and the edges common to two plate segments must have compatible displacements, rotations, shear forces, and moments. It is obtained by using carefully chosen series that solve the combined partial differential equations of motion, for in-plane and out-of-plane deformations for all possible combinations of edge conditions. The number of terms in the series is taken such that convergence is ensured to the number of digits as shown. Examples of the new solutions are given and compared with available solutions for the same cases. [ABSTRACT FROM AUTHOR]

An elastic multiple shell model is used for the vibration analysis of multiwalled carbon nanotubes (MWCNTs). The van der Waals (vdW) interaction between any two layers of the MWCNT is modeled as the radius-dependent function. Based on the simplified Donnell shell equations, explicit formulas are obtained for the radial-dominated natural frequencies and mode shapes of double- and triple-walled carbon nanotubes. The natural frequencies are calculated for MWCNT with various radii and number of tubes. The numerical results show that the effect of vdW interaction on the torsionally and longitudinally dominated natural frequencies is very small and can be neglected, and the vdW interaction has only a small influence on the lowest radial-dominated natural frequency, but plays a significant role in the higher radial-dominated natural frequencies for various combinations of m (number of longitudinal) and n (number of circumferential) waves in the mode even for the MWCNTs of small innermost radius. Especially, due to the effect of vdW interaction, there exists a change over in the order of the modes, from radially dominated mode to longitudinally dominated mode, or from longitudinally dominated mode to torsionally dominated mode even when the innermost radius of the MWCNT is very small, indicating that the interlayer vdW interaction plays a significant role in the vibration of MWCNTs with small radius. The effect of the mode order on the natural frequencies of MWCNT is also examined in detail. [ABSTRACT FROM AUTHOR]

We present a novel approach for solving the correspondence problem between a given pair of input shapes with non‐rigid, nearly isometric pose difference. Our method alternates between calculating a deformation field and a sparse correspondence. The deformation field is constructed with a low rank Fourier basis which allows for a compact representation. Furthermore, we restrict the deformation fields to be divergence‐free which makes our morphings volume preserving. This can be used to extract a correspondence between the inputs by deforming one of them along the deformation field using a second order Runge‐Kutta method and resulting in an alignment of the inputs. The advantages of using our basis are that there is no need to discretize the embedding space and the deformation is volume preserving. The optimization of the deformation field is done efficiently using only a subsampling of the orginal shapes but the correspondence can be extracted for any mesh resolution with close to linear increase in runtime. We show 3D correspondence results on several known data sets and examples of natural intermediate shape sequences that appear as a by‐product of our method. [ABSTRACT FROM AUTHOR]

Background: African-American men have earlier onset of prostate cancer, higher prostate-specific antigen (PSA) levels, more advanced stage at diagnosis, and higher mortality than white men. It is not known whether the poorer survival of African-American men with prostate cancer reflects their later stage at diagnosis or differences in the basic biology of their disease. To evaluate this question, we examined outcomes of African-American and white men with metastatic prostate cancer in the context of a randomized clinical trial.Methods: Southwest Oncology Group Study 8894 was a randomized phase III trial that compared orchiectomy with or without flutamide in men with metastatic prostate cancer. Using data from 288 African-American and 975 white men in the trial, we conducted a proportional hazards regression analysis to determine if ethnicity was an independent predictor of survival. All statistical tests were two-sided.Results: African-American men were more likely than white men to have extensive disease and bone pain and had poorer performance status, younger age at study entry, higher Gleason score, and higher PSA levels. After adjustment for these prognostic variables, the hazard ratio (HR) for all-cause mortality for African-American men relative to white men was 1.23 (P: =.018). Further adjustment for initial quality-of-life assessments also resulted in higher HRs associated with African-American ethnicity relative to white ethnicity (HR = 1.39; P: =.007).Conclusions: African-American men with metastatic prostate cancer have a statistically significantly worse prognosis than white men that cannot be explained by the prognostic variables explored in this study. These data should give increased impetus for efforts to detect the disease early in African-American men and for the development of more effective therapies based on potential biologic differences in this ethnic group. [ABSTRACT FROM AUTHOR]

Background:PSA doubling time (PSADT) is an attractive intermediate end point for assessing novel therapies in biochemically recurrent prostate cancer (BRPC). This study explores whether PSADT calculations are influenced by frequency/duration of PSA measurements, and whether statistical variability leads investigators to find false significant results.Methods:In retrospective analyses of two BRPC cohorts: Johns Hopkins Hospital (JHH) patients who deferred therapy and placebo patients on a randomized clinical trial (RCT), we calculated changes in PSADT from early measurements to later measurements using subsets of available PSAs for patients with 6 and 9 PSAs. We simulated hypothetical single-arm trials using randomly selected, 50-patient subsets and simulated two-arm RCTs.Results:JHH cohort (n=205) had median follow-up 58 months, median age 61 years and median Gleason 7. PSA variability changed with duration of PSA measurement as median within-patient PSADT increases for men with >6 PSAs ranged from 1.0 to 1.4 months by PSA subset while increases for men with 9 PSAs ranged from 3.9 to 4.1 months. Frequency of measurement did not change PSA variability as PSADT increase was unchanged when odd values were used instead of all values. Approximately 30% of JHH men experienced >200% increases in PSADT. Up to 62% of 50-patient single-arm simulations detected a significant PSADT change, whereas simulated RCTs did not. Results were supported in the RCT placebo cohort; 46% of patients experienced PSADT increases >200%.Conclusions:These data suggest that calculated PSADT in BRPC may naturally increase over time in the absence of therapy and may be influenced by duration of PSA follow-up. As a result, single-arm trials could show false significant increases despite the lack of active treatment of these patients. Placebo-controlled RCTs including clinical end points are recommended to screen novel agents in men with BRPC to mitigate bias because of natural PSADT variability. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the relationship of baseline body mass index (BMI) and serum testosterone level with prostate cancer outcomes in men with castration-resistant metastatic prostate cancer (CRPC). BMI and testosterone levels were evaluated for their ability to predict overall survival (OS) and prostate-specific antigen (PSA) declines in the TAX327 clinical trial, an international phase III randomized trial of one of the two schedules of docetaxel and prednisone compared with mitoxantrone and prednisone. In this study of 1006 men with CRPC, the median serum testosterone level was 14.5 ng per 100 ml (range 0–270), the median BMI was 27 kg m−2 (range 15.7–46.5), and 26% of men were obese or morbidly obese (BMI30). Obesity was associated with younger age, lower PSA and alkaline phosphatase levels, and higher performance status, primary Gleason sum, testosterone and hemoglobin compared to absence of obesity. In multivariate analysis, neither BMI, presence of obesity, nor baseline testosterone was significantly associated with OS or PSA declines. Higher testosterone levels among obese men suggest incomplete gonadal suppression with current therapies, but these differences may not be clinically relevant in men with CRPC. There was evidence of potential hemodilution of PSA and alkaline phosphatase levels in obese men.Prostate Cancer and Prostatic Diseases (2009) 12, 88–93; doi:10.1038/pcan.2008.36; published online 24 June 2008 [ABSTRACT FROM AUTHOR]

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This paper is concerned with the bending problem of micro- and nanobeams based on the Eringen nonlocal elasticity theory and Timoshenko beam theory. In the former theory, the small-scale effect is taken into consideration while the effect of transverse shear deformation is accounted for in the latter theory. The governing equations and the boundary conditions are derived using the principle of virtual work. General solutions for the deflection, rotation, and stress resultants are presented for transversely loaded beams. In addition, specialized bending solutions are given for beams with various end conditions. These solutions account for a better representation of the bending behavior of short, stubby, micro- and nanobeams where the small-scale effect and transverse shear deformation are significant. Considering particular loading and boundary conditions, the effects of small-scale and shear deformation on the bending results may be observed because of the analytical forms of the solutions. [ABSTRACT FROM AUTHOR]

The aim of the current in vitro study was to evaluate the load-bearing capacity of provisional four-unit bridges with and without two different types of glass-fibre reinforcement produced in a direct technique with a silicon template from the composite materials Protemp, Luxatemp and CronMix. From each composite material, 30 bridges were manufactured, 10 without fibre reinforcement, 10 with Stick/StickNet and 10 with everStick/everStickNet reinforcement. After artificial aging by thermocycling samples were cemented onto a master model and subjected to load testing in a universal testing machine. Mean force at fracture for the groups without fibre reinforcement varied from 486 to 612 N. Depending on the material combination, fibre reinforcement resulted in a slightly increased or a reduced mean load-bearing capacity, varying from 674 N for the combination of Protemp and Stick to 262 N for CronMix and everStick. Position of fibres within the resin pontic was found to have an important influence on load-bearing capacity of reinforced bridges. Scanning electron microscopic investigation showed good adhesion of everStick fibres to the pre-impregnation resin whereas bonding of Stick fibres to the embedding polymer was incomplete. In conclusion, fibre reinforcement with Stick or everStick did not improve the load-bearing capacity of direct provisional bridges made from Protemp, Luxatemp, or CronMix as the position of fibres could not be controlled during the direct manufacturing process. To increase the load-bearing capacity of the provisional bridges, an exact positioning of fibres at the tension side in the dental laboratory is necessary. [ABSTRACT FROM AUTHOR]

The belief that hormone-refractory prostate cancer (HRPC) is a chemotherapy-resistant disease has been effectively refuted by the results of two recent randomized phase III trials. The TAX327 trial compared weekly docetaxel, every-3-weeks (Q3W) docetaxel, and Q3W mitoxantrone plus prednisone in 1,006 patients with HRPC, and results demonstrated that survival was significantly longer with a docetaxel-based regimen than with mitoxantrone. That trial demonstrated that only Q3W docetaxel was significantly superior to mitoxantrone with respect to overall survival. Quality of life was also superior in the docetaxel groups. In the Southwest Oncology Group (SWOG) 9916 trial, 674 men with progressive HRPC were randomized to 3-week cycles of docetaxel plus estramustine or mitoxantrone plus prednisone. Overall and disease-free survival times were significantly longer in the docetaxel arm. Collectively, the results of these trials demonstrate that survival can be significantly improved with chemotherapy in patients with HRPC to an extent that is comparable with the survival benefits seen in other cancers considered sensitive to chemotherapy such as breast cancer. Among various research tasks in HRPC is the definition of potential surrogate end points for survival, which will facilitate the conduct of pivotal trials. Prostate-specific antigen (PSA) response rate and changes in PSA constructs (i.e., PSA doubling time and PSA velocity) are promising potential surrogate end points for future trials and are being actively evaluated at the present time. Until there is clear demonstration of a surrogate role for these alternative end points, survival remains the appropriate end point for phase III trials in HRPC. There is a need for safe and effective second- and third-line regimens for patients progressing after docetaxel, and these patients should enter clinical trials designed for this population. Mitoxantrone, vinorelbine, the platinum analogue satraplatin, and epothilone are among compounds that require careful testing in this setting. The addition of targeted therapies, such as the endothelin receptor antagonist, atrasentan, and angiogenesis inhibitors, such as thalidomide and bevacizumab, to docetaxel-based therapy is being evaluated. High-dose calcitriol may also be an effective addition to docetaxel. The extensive effort devoted to the evaluation of chemotherapy and other systemic modalities of treatment of HRPC is likely to yield additional clinical benefit for patients, making HRPC a more manageable, less lethal, and less debilitating disease. [ABSTRACT FROM AUTHOR]

Context: The natural history of biochemical recurrence after radical prostatectomy can be long but variable. Better risk assessment models are needed to identify men who are at high risk for prostate cancer death early and who may benefit from aggressive salvage treatment and to identify men who are at low risk for prostate cancer death and can be safely observed.Objectives: To define risk factors for prostate cancer death following radical prostatectomy and to develop tables to risk stratify for prostate cancer-specific survival.Design, Setting, and Patients: Retrospective cohort study of 379 men who had undergone radical prostatectomy at an urban tertiary care hospital between 1982 and 2000 and who had a biochemical recurrence and after biochemical failure had at least 2 prostate-specific antigen (PSA) values at least 3 months apart in order to calculate PSA doubling time (PSADT). The mean (SD) follow-up after surgery was 10.3 (4.7) years and median follow-up was 10 years (range, 1-20 years).Main Outcome Measure: Prostate cancer-specific mortality.Results: Median survival had not been reached after 16 years of follow-up after biochemical recurrence. Prostate-specific doubling time (<3.0 vs 3.0-8.9 vs 9.0-14.9 vs > or =15.0 months), pathological Gleason score (< or =7 vs 8-10), and time from surgery to biochemical recurrence (< or =3 vs >3 years) were all significant risk factors for time to prostate-specific mortality. Using these 3 variables, tables were constructed to estimate the risk of prostate cancer-specific survival at year 15 after biochemical recurrence.Conclusion: Clinical parameters (PSADT, pathological Gleason score, and time from surgery to biochemical recurrence) can help risk stratify patients for prostate cancer-specific mortality following biochemical recurrence after radical prostatectomy. These preliminary findings may serve as useful guides to patients and their physicians to identify patients at high risk for prostate cancer-specific mortality following biochemical recurrence after radical prostatectomy to enroll them in early aggressive treatment trials. In addition, these preliminary findings highlight that survival in low-risk patients can be quite prolonged. [ABSTRACT FROM AUTHOR]

The exact buckling loads of columns with internal slide release are found using the exact stiffness matrix of the column including the effect of the axial forces. Two types of columns are considered: clamped-clamped and clamped-simply supported with internal slide release at variable locations along the member. It is found that for both the clamped-clamped and the clamped-simply supported columns the buckling load is constant and does not depend on the location of the slide discontinuity. [ABSTRACT FROM AUTHOR]

The exact vibration frequencies of continuous beams with internal releases are found using the dynamic stiffness method. Two types of releases are considered: hinge and sliding discontinuities. First, the exact dynamic stiffness matrix for a beam element with a release is derived and then used in the assembly of the structure dynamic stiffness matrix. The natural frequencies are found as the values of frequency that make this matrix singular. Then the mode shapes are found exactly. Examples are given for continuous beams with different releases. [ABSTRACT FROM AUTHOR]

In this work the exact axisymmetric vibration frequencies of circular and annular variable thickness plates are found. The solution is obtained using the exact element method developed earlier. It allows for the exact solution of problems with general polynomial variation in thickness using infinite power series. The solution is exact up to the accuracy of the computer. The natural frequencies of vibration are found as the solutions of the frequency equation. Normalized values for the natural frequencies are given for linear, parabolic and cubic variations of the plate thickness, for circular and annular plates, with four types of boundary conditions on the inner and outer boundaries. [ABSTRACT FROM AUTHOR]

Background: Previous studies indicate that suramin may be an active agent for treatment of solid tumors. The clinical use of suramin is complicated by a broad spectrum of toxic effects and complex pharmacology. Studies have suggested that the dose-limiting neurotoxicity of this agent is closely related to sustained plasma drug concentrations of 350 micrograms/mL or more.Purpose: This phase I clinical trial in patients with solid tumors was designed to determine whether plasma concentrations resulting in both antitumor activity and manageable toxicity could be achieved with short, intermittent infusions of suramin.Methods: Thirty-seven patients, including 33 with metastatic, hormone-refractory prostate cancer, collectively received 43 courses of suramin designed to maintain a plasma concentration range of 200-300, 175-275, or 150-250 micrograms/mL. Patients received a test dose of 200 mg and an initial loading dose of 1000 mg/m2 on day 1 of therapy. Subsequent suramin doses and schedules were individually determined using a strategy of adaptive control with feedback, which used a maximum a posteriori Bayesian algorithm to estimate individual pharmacokinetic parameters. Patients were treated until dose-limiting toxicity or progressive disease developed.Results: Thirty-five of the 37 study patients and 31 of the 33 with prostate cancer were assessable for toxicity and response. Treatment was discontinued in 28 patients because of dose-limiting toxicity consisting of a syndrome of malaise, fatigue, and lethargy; recurrent reduction in creatinine clearance of 50% or more; or axonal neuropathy. Evidence of major antitumor activity was observed in patients with prostate cancer treated at all three plasma drug concentrations. Measurable responses (one complete response and five partial responses) were noted in six of 12 patients with measurable disease. Twenty-four (77%) of 31 patients had a reduction in prostate-specific antigen of 50% or more, and 17 (55%) of 31 had a reduction of 75% or more. Twenty (83%) of 24 patients reported reduction in pain.Conclusions: Suramin can be safely administered as an intermittent bolus injection by use of adaptive control with feedback to control plasma drug concentrations; toxicity is significant but manageable and reversible. Suramin is active against hormone-refractory prostate cancer.Implications: Future trials should address the role and necessary extent of therapeutic drug monitoring; the optimal plasma drug concentration range and duration of therapy; and the activity of suramin in combination with other agents, in earlier stages of prostate cancer, and in other tumor types. [ABSTRACT FROM AUTHOR]

In this research we present a new analytical solution for finding the buckling loads of thin isotropic and orthotropic rectangular plates in which all four corners are supported. This new solution is also capable of solving all cases where few or all the edges are supported. The methods that are currently known in the literature for finding the buckling loads of plates are mainly numerical. Although some plates with specific boundary conditions have analytical solutions, a comprehensive analytical method providing analytical solutions that fit all possible combinations of boundary conditions is lacking. The solution method in this study is based on the development of a static solution for a plate. The physical meaning of buckling is the loss of stiffness, and it is found as the value of the in‐plane loading intensity at which a zero force on the plate surface will generate infinite displacement. The solution is obtained in series form, and the coefficients are solved to match the edge conditions. Using this new method, exact buckling loads and buckling modes of many new cases of classical boundary conditions are found. Results are given for several stiffness ratios in both directions of the plate, and for uni‐directional and bi‐directional loading. [ABSTRACT FROM AUTHOR]

The article reports on the use of percutaneous angioplasty to facilitate the implantation of the left ventricular pacemaker of a 68-year-old man with heart failure. The operation was performed via the left subclavian vein. The surgery underwent to upgrade an existing dual chamber internal cardioverter-defibrillator to a biventricular system. It is noted that the coronary venoplasty and stenting are valuable techniques for facilitating percutaneous placement of a left ventricular pacing.