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We study the boundary controllability of 2×2 system of heat equations by using a flatness approach. According to the relation between the diffusion coefficients of the heat equation, it is known that the system can be neither null-controllable nor null-controllable for any T>T0, where T0∈[0,∞]. Here we recover this result in the case that T0∈[0,∞) by using the flatness method, and we obtain an explicit formula for the control and for the corresponding solutions. In particular, the state and the control have Gevrey regularity in time and in space. [ABSTRACT FROM AUTHOR]

We show the local null-controllability of a fluid-structure interaction system coupling a viscous incompressible fluid with a damped beam located on a part of its boundary. The controls act on arbitrary small parts of the fluid domain and of the beam domain. In order to show the result, we first use a change of variables and a linearization to reduce the problem to the null-controllability of a Stokes-beam system in a cylindrical domain. We obtain this property by combining Carleman inequalities for the heat equation, for the damped beam equation and for the Laplace equation with high-frequency estimates. Then, the result on the nonlinear system is obtained by a fixed-point argument. [ABSTRACT FROM AUTHOR]

We consider the controllability of an abstract parabolic system by using switching controls. More precisely, we show that, under general hypotheses, if a parabolic system is null-controllable for any positive time with N controls, then it is also null-controllable with the property that at each time, only one of these controls is active. The main difference with previous results in the literature is that we can handle the case where the main operator of the system is not self-adjoint. We give several examples to illustrate our result: coupled heat equations with terms of orders 0 and 1, the Oseen system or the Boussinesq system. [ABSTRACT FROM AUTHOR]

Purpose: Although the Palliative Prognostic Index (PPI) has been used to predict survival in various cancers, to our knowledge, no study has examined its applicability in gastric cancer. This study aimed to determine the baseline PPI cutoff value for recommending single-fraction radiotherapy in patients with bleeding gastric cancer. Materials and methods: This was a secondary analysis of the Japanese Radiation Oncology Study Group (JROSG) 17–3, a multicenter prospective study of palliative radiotherapy for bleeding gastric cancer. Discrimination was evaluated using a time-dependent receiver operating characteristic curve, and the optimal cutoff value was determined using the Youden index. A calibration plot was used to assess the agreement between predicted and observed survival. Results: We enrolled 55 patients in JROSG 17–3. The respective median survival times were 6.7, 2.8, and 1.0 months (p = 0.021) for patients with baseline PPI scores of ≤ 2, 2 4. The areas under the curve for predicting death within 2, 3, 4, and 5 months were 0.813, 0.787, 0.775, and 0.721, respectively. The negative predictive value was highest when survival

Purpose: The aim of this study was to understand the income and employment status of patients at the start of and during follow-up after palliative radiation therapy for bone metastasis. Methods and Materials: From December 2020 to March 2021, a prospective multi-institutional observational study was conducted to investigate income and employment of patients at the start of administration of radiation therapy for bone metastasis and at 2 and 6 months after treatment. Of 333 patients referred to radiation therapy for bone metastasis, 101 were not registered, mainly because of their poor general condition, and another 8 were excluded from the follow-up analysis owing to ineligibility. Results: In 224 patients analyzed, 108 had retired for reasons unrelated to cancer, 43 had retired for reasons related to cancer, 31 were taking leave, and 2 had lost their jobs at the time of registration. The number of patients who were in the working group was 40 (30 with no change in income and 10 with decreased income) at registration, 35 at 2 months, and 24 at 6 months. Younger patients (P = 0), patients with better performance status (P = 0), patients who were ambulatory (P = .008), and patients with lower scores on a numerical rating scale of pain (P = 0) were significantly more likely to be in the working group at registration. There were 9 patients who experienced improvements in their working status or income at least once in the follow-up after radiation therapy. Conclusions: The majority of patients with bone metastasis were not working at the start of or after radiation therapy, but the number of patients who were working was not negligible. Radiation oncologists should be aware of the working status of patients and provide appropriate support for each patient. The benefit of radiation therapy to support patients continuing their work and returning to work should be investigated further in prospective studies.

We analyze a bidimensional fluid-structure interaction system composed of a viscous incompressible fluid and a beam located at the boundary of the fluid domain. Our main result is the existence and uniqueness of strong solutions for the corresponding coupled system. The proof is based on a the study of the linearized system and a fixed point procedure. In particular, we show that the linearized system can be written with a Gevrey class semigroup. The main novelty with respect to previous results is that we do not consider any approximation in the beam equation. [ABSTRACT FROM AUTHOR]

Abstract This study aimed to evaluate the robustness against geometric uncertainties in the hybrid intensity-modulated radiation therapy (IMRT) plans generated by commercially available software for automated breast planning (ABP). The ABP plans were compared with commonly used forward-planned field-in-field (FIF) technique plans. The planning computed tomography datasets of 20 patients who received left-sided breast-conserving surgery were used for both the ABP and FIF plans. Geometric uncertainties were simulated by shifting beam isocenters by 2, 3, 5, and 10 mm in the six directions: anterior/posterior, left/right, and superior/inferior. A total of 500 plans (20 patients and 25 scenarios, including the original plan) were created for each of the ABP and FIF plans. The homogeneity index of the target volume in the ABP plans was significantly better (p

We propose a new model in a fluid-rigid structure system composed by a rigid body and a viscous incompressible fluid using a boundary condition based on Coulomb's law. This boundary condition allows the fluid to slip on the boundary if the tangential component of the stress is too large. In the opposite case, we recover the standard Dirichlet boundary condition. The governing equations are the Navier-Stokes system for the fluid and the Newton laws for the body. The corresponding coupled system can be written as a variational inequality. We prove that there exists a weak solution of this system. [ABSTRACT FROM AUTHOR]

Purpose: A quality indicator (QI) is a valuable tool to evaluate the quality of health care systems. In palliative radiation oncology, only a few related QIs have been developed to date. In this study, we sought to develop and pilot test QIs that assess the quality of care in palliative radiation therapy. Methods and Materials: A modified Delphi method was used to establish consensus with an expert panel. The panel consisted of 8 radiation oncologists who have expertise in palliative radiation oncology and 1 expert on Delphi methodology. Online panel meetings and e-mail surveys were conducted to develop QIs on palliative radiation therapy for bone and brain metastases. Feasibility of measurement was assessed though pilot surveys that were conducted by radiation oncologists at 5 facilities. Results: After 3 online meetings and 2 e-mail surveys, we developed 4 QIs on bone metastases and 3 QIs on brain metastases. Two email surveys and 2 pilot surveys confirmed the validity of QIs and the feasibility of measurement, respectively. Conclusions: We developed valid and feasible QIs on palliative radiation therapy for bone and brain metastases. Our work may contribute to reduce the evidence–practice gaps in palliative radiation oncology.

We consider the geometrical inverse problem consisting in recovering an unknown obstacle in a viscous incompressible fluid by measurements of the Cauchy force on the exterior boundary. We deal with the case where the fluid equations are the nonstationary Stokes system and using the enclosure method, we can recover the convex hull of the obstacle and the distance from a point to the obstacle. With the same method, we can obtain the same result in the case of a linear fluid-structure system composed by a rigid body and a viscous incompressible fluid. We also tackle the corresponding nonlinear systems: the Navier-Stokes system and a fluid-structure system with free boundary. Using complex spherical waves, we obtain some partial information on the distance from a point to the obstacle. [ABSTRACT FROM AUTHOR]

We consider a class of low Reynolds number swimmers, of prolate spheroidal shape, which can be seen as simplified models of ciliated microorganisms. Within this model, the form of the swimmer does not change, the propelling mechanism consisting in tangential displacements of the material points of swimmer's boundary. Using explicit formulas for the solution of the Stokes equations at the exterior of a translating prolate spheroid the governing equations reduce to a system of ODE's with the control acting in some of its coefficients (bilinear control system). The main theoretical result asserts the exact controllability of the prolate spheroidal swimmer. In the same geometrical situation, we consider the optimal control problem of maximizing the efficiency during a stroke and we prove the existence of a maximum. We also provide a method to compute an approximation of the efficiency by using explicit formulas for the Stokes system at the exterior of a prolate spheroid, with some particular tangential velocities at the fluid-solid interface. We analyze the sensitivity of this efficiency with respect to the eccentricity of the considered spheroid and show that for small positive eccentricity, the efficiency of a prolate spheroid is better than the efficiency of a sphere. Finally, we use numerical optimization tools to investigate the dependence of the efficiency on the number of inputs and on the eccentricity of the spheroid. The "best" numerical result obtained yields an efficiency of 30:66% with 13 scalar inputs. In the limiting case of a sphere our best numerically obtained efficiency is of 30:4%, whereas the best computed efficiency previously reported in the literature is of 22%. [ABSTRACT FROM AUTHOR]

There are currently no reliable, established serum biomarkers to predict the prognosis of radiotherapy for advanced cervical cancer. We aimed to identify serum biomarkers for survival after radiotherapy for cervical cancer. In this multicenter prospective cohort study, the usefulness of pre- and posttreatment serum protein levels of potential biomarkers, including squamous cell carcinoma antigen (SCC-Ag), apolipoprotein C-II (ApoC-II), matrix metalloproteinase (MMP)1, and MMP2, were evaluated together with clinical factors in 145 cervical cancer patients in order to determine their suitability to predict survival. Progression-free survival (PFS) was the primary endpoint, and overall survival (OS), pelvic PFS (PPFS), and distant metastasis-free survival (DMFS) were the secondary endpoints. Blood samples were collected before and 1 month after radiotherapy to measure serum biomarker levels. ApoC-II was measured using a monoclonal antibody-based enzyme-linked immunosorbent assay, which was developed for this purpose. Kaplan-Meier method, log-rank test, and univariate and multivariate Cox proportional hazards models were used for statistical analyses. In multivariate analysis, larger tumor size was independently associated with shorter PFS, OS, PPFS, and DMFS, while longer overall treatment time was independently associated with shorter PPFS. Higher pretreatment SCC-Ag (P < 0.001) was associated with shorter DMFS. Higher posttreatment SCC-Ag (P = 0.017) was also associated with shorter DMFS. Pretreatment ApoC-II was associated with PPFS in univariate analysis (P = 0.048), but not in multivariate analysis. Patients with pretreatment ApoC-II levels ≤ 25.8 μg/ml had shorter PPFS than those with pretreatment ApoC-II levels > 25.8 μg/ml (P = 0.023, log-rank test). Pre- and posttreatment serum SCC-Ag and pretreatment serum ApoC-II levels may be important biomarkers to predict survival outcomes of patients with cervical cancer after radiotherapy. Pre- and posttreatment SCC-Ag and pretreatment ApoC-II might be useful in clinical settings for screening patients to improve treatment strategies in cervical cancer.

Abstract Introduction The incidence of prostate cancer in Japan continues to increase, necessitating the continued development of effective therapies and strategies. Recent advances in treatments have improved the prognosis of metastatic disease and highlighted the importance of treating bone metastases to reduce the incidence of skeletal complications and improve patients’ quality of life. With the increasing number of treatment options that have become available, including bone-targeted therapy with the alpha emitter radium-223 dichloride (Ra-223), Japanese clinicians are faced with making difficult decisions on the choice of optimal treatment strategy. In such situations, guidance based on expert opinions can be beneficial. Methods A panel meeting of 27 Japanese experts in the management of prostate cancer was held to share opinions and to establish consensus recommendations on key clinical questions. Panelists were asked to vote on more than 40 questions pertinent to prostate cancer, and the answers helped guide a comprehensive discussion. Results The panel reached a consensus on key topics related to the optimal treatment strategy for Ra-223 therapy, namely, that patients with symptomatic, metastatic castration-resistant prostate cancer (CRPC) would benefit most from the use of this agent and that this treatment therapy should be provided before chemotherapy. Other topics that achieved consensus included: monitoring for osteoporosis and providing treatment if necessary during androgen deprivation therapy; performing magnetic resonance imaging in the presence of discrepancies in bone scintigram and computed tomography scans; monitoring alkaline phosphatase during CRPC treatment; using osteoclast-targeting in patients with CRPC with bone metastases; and using osteoclast-targeted agents combined with Ra-223. Conclusion These consensus recommendations and the updated information which became available subsequent to the panel meeting included here provide useful information for clinicians to aid in designing optimal treatment strategies for their patients. Funding Bayer Yakuhin Ltd.

Abstract  In this paper, we consider the interaction between a rigid body and an incompressible, homogeneous, viscous fluid. This fluid-solid system is assumed to fill the whole space ℝ d , d = 2 or 3. The equations for the fluid are the classical Navier-Stokes equations whereas the motion of the rigid body is governed by the standard conservation laws of linear and angular momentum. The time variation of the fluid domain (due to the motion of the rigid body) is not known a priori, so we deal with a free boundary value problem. We improve the known results by proving a complete wellposedness result: our main result yields a local in time existence and uniqueness of strong solutions for d = 2 or 3. Moreover, we prove that the solution is global in time for d = 2 and also for d = 3 if the data are small enough. [ABSTRACT FROM AUTHOR]

In this paper, we consider a two-dimensional fluid-rigid body problem. The motion of the fluid is modelled by the Navier-Stokes equations, whereas the dynamics of the rigid body is governed by the conservation laws of linear and angular momentum. The rigid body is supposed to be an infinite cylinder of circular cross-section. Our main result is the existence and uniqueness of global strong solutions. [ABSTRACT FROM AUTHOR]

700°C class A-USC (Advanced Ultra Super Critical) thermal power plant is one of the solutions to reduce carbon dioxide (CO2) emission. In order to meet the design requirement, which is capable to be operated under 700°C steam condition, the development of Ni-based superalloys is essential. Fundamental research and demonstration of mock-up plants have been driven by national project in Japan, US, Europe and China, to confirm the reliability of Ni-based superalloys. One issue of superalloys reported by others is the stress accelerated grain boundary oxidation (SAGBO), leading to the deterioration of creep rupture properties during service. We newly manufactured the test apparatus which enables to creep test under high temperature steam environment, and evaluated the grain boundary oxidation behavior of Ni-based rotor material, TOS1X-2, under various stresses and atmosphere. Microstructure observation after creep tested at 750°C for 2,500h, found that thin layer of Cr-rich and Al-rich oxides form at all stress and atmosphere condition. Detail studies revealed that the Al-rich oxide were formed at fine, recrystallized grain boundary, which is driven by initially induced strain by machining. The quantitative analysis of microstructure showed that steam atmosphere slightly accelerates the grain boundary oxidation. On the contrary, effect of applied stress on oxidation depth was not observed. The grain boundary oxidation observed in this study was very small, suggesting that TOS1X-2 exhibits good oxidation and creep rupture properties in 700°C A-USC operating condition.

In this paper, we consider a system modeling the interaction between a viscous incompressible fluid and an elastic structure. The fluid motion is represented by the classical Navier–Stokes equations while the elastic displacement is described by the linearized elasticity equation. The elastic structure is immersed in the fluid and the whole system is confined into a general bounded smooth domain of . Our main result is the local in time existence and uniqueness of a strong solution of the corresponding system. [ABSTRACT FROM AUTHOR]