Design and application of magneto-rheological fluid

Magneto-Rheological Fluid (MRF) technology is an old “newcomers” coming to the market at high speed. Various industries including the automotive industry are full of potential MRF applications. Magneto-Rheological Fluid technology has been successfully employed already in various low and high volume applications. A structure based on MRF might be the next generation in design for products where power density, accuracy and dynamic performance are the key features. Additionally, for products where is a need to control fluid motion by varying the viscosity, a structure based on MRF might be an improvement in functionality and costs. Two aspects of this technology, direct shear mode (used in brakes and clutches) and valve mode (used in dampers) have been studied thoroughly and several applications are already present on the market. Excellent features like fast response, simple interface between electrical power input and mechanical power output, and precise controllability make MRF technology attractive for many applications. This paper presents the state of the art of an actuator with a control arrangement based on MRF technology. The study shows that excellent features like fast response, simple interface between electrical power input and the mechanical power output, and controllability make MRF the next technology of choice for many applications

12/Objawy uboczne radykalnego leczenia radioterapią raka stercza: ocena 4-letnich doświadczeń

CelOcena wczesnych i późnych objawów radioterapii konformalnej u chorych z miejscowo zaawansowanym rakiem stercza.Materiał i metodyAnalizie poddano 267 chorych z rakiem stercza (T1-T3NxM0), którzy przebyli leczenie radioterapią 3D CRT w okresie od maja 1999 do lutego 2003 r. w Wielkopolskim Centrum Onkologii w Poznaniu. Pacjenci reprezentowali następujące stadium zaawansowania procesu chorobowego: (T1 = 65 chorych, T2 = 112 chorych, T3 = 90 chorych). Średni poziom PSA przed leczeniem radioterapią wynosił 18 ng/ml (0,5–112 ng/ml). Średnia dawka całkowita wynosiła 70.4 Gy (od 63.8 Gy do 74 Gy), a dawka frakcyjna 1.8 Gy lub 2.0 Gy. U 170 (64%) chorych przed rozpoczęciem napromieniania włączono leczenie hormonalne, a u 32 (12%) pacjentów również przed rozpoczęciem radioterapii przeprowadzono zabieg TURP. Wczesną i późną toksyczność ze strony układu moczowego (GU) i przewody pokarmowego (Gl) oceniono w oparciu o klasyfikację RTOG/EORTC. Średni czas obserwacji dla całej grupy wynosił 23.5 miesięcy (od 6 do 54 miesięcy).WynikiNasilenie wczesnego odczynu popromiennego ze strony przewodu pokarmowego (Gl) zawierające się w przedziale od 0-l stwierdzono u 80% pacjentów, a ze strony układu moczowego (GU) u 75%. Odczyn wczesny w stopniu II w odniesieniu do przewodu pokarmowego odnotowano u 20% leczonych pacjentów, a układu moczowego u 25%. U żadnego z analizowanych chorych nie stwierdzono nasilenia wczesnej reakcji popromiennej w stopniu III. Późne powikłania popromienne przedstawiały się następująco ze strony Gl: stopień 1 = 7% chorych, stopień II = 4% chorych, a powikłania w odniesieniu do GU: stopien I = 10% chorych, stopień II = 4%, a w stopniu III = 0.5%. Nie odnotowano powiklań w stopniu III dla GI. Średni czas ujawnienia się objawów póznych dla stopnia I wynosił 8 miesięcy, a stopnia II 13 miesięcy. Jedynie wysoka dawka całkowita (p=0.01) oraz wykonany zabieg TURP (p=0.02) byly związane z nasileniem późnych powikłań popromiennych.PodsumowanieWstępne wyniki leczenia wskazują, że radioterapia jest metodą bezpieczną i dobrze tolerowaną przez pacjentów. Do czynników wpływających na intensywność powikłań należy w pierwszej kolejności zaliczyć wysoką dawkę całkowitą oraz przebyty zabieg TURP

Electrohydraulic Drive with a Flow Valve Controlled by a Permanent Magnet Synchronous Motor

This article presents an electrohydraulic drive with a new electrohydraulic flow valve controlled by a Permanent Magnet Synchronous Motor (PMSM), designed and built by the authors. In comparison to a valve with a proportional electromagnet, the use of a PMSM has enabled significant improvements in the key characteristics of the valve. A theoretical framework and a model of a PMSM are presented; subsequently, a valve with this motor is proposed and tested. Step responses of the real valve and its static and frequency characteristics are measured. The characteristics obtained in the simulation are compared with those obtained in the laboratory investigations, showing their good compliance. The obtained characteristics of the new valve are better than those of a typical proportional valve. The new valve is applied in an electrohydraulic linear actuator. For positioning tasks, two types of controllers are applied and compared: a proportional-derivative controller and a fractional order proportional-derivative controller showing satisfactory parameters

SU(2) Cosmological Solitons

We present a class of numerical solutions to the SU(2) nonlinear $\sigma$-model coupled to the Einstein equations with cosmological constant $\Lambda\geq 0$ in spherical symmetry. These solutions are characterized by the presence of a regular static region which includes a center of symmetry. They are parameterized by a dimensionless ``coupling constant'' $\beta$, the sign of the cosmological constant, and an integer ``excitation number'' $n$. The phenomenology we find is compared to the corresponding solutions found for the Einstein-Yang-Mills (EYM) equations with positive $\Lambda$ (EYM$\Lambda$). If we choose $\Lambda$ positive and fix $n$, we find a family of static spacetimes with a Killing horizon for $0 \leq \beta < \beta_{max}$. As a limiting solution for $\beta = \beta_{max}$ we find a {\em globally} static spacetime with $\Lambda=0$, the lowest excitation being the Einstein static universe. To interpret the physical significance of the Killing horizon in the cosmological context, we apply the concept of a trapping horizon as formulated by Hayward. For small values of $\beta$ an asymptotically de Sitter dynamic region contains the static region within a Killing horizon of cosmological type. For strong coupling the static region contains an ``eternal cosmological black hole''.Comment: 20 pages, 6 figures, Revte

Radiotherapy combined with hormonal therapy in prostate cancer: the state of the art

Androgen-deprivation therapy (ADT) is used routinely in combination with definitive external beam radiation therapy (EBRT) in patients with high-risk clinically localized or locally advanced disease. The combined treatment (ADT–EBRT) also seems to play a significant role in improving treatment results in the intermediate-risk group of prostate cancer patients. On the other hand, there is a growing body of evidence that treatment with ADT can be associated with serious and lifelong adverse events including osteoporosis, cardiovascular disease, diabetes, and many others. Almost all ADT adverse events are time dependant and tend to increase in severity with prolongation of hormonal manipulation. Therefore, it is crucial to clearly state the optimal schedule for ADT in combination with EBRT, that maintaining the positive effect on treatment efficacy would keep the adverse events risk at reasonable level. To achieve this goal, treatment schedule may have to be highly individualized on the basis of the patient-specific potential vulnerability to adverse events. In this study, the concise and evidence-based review of current literature concerning the general rationales for combining radiotherapy and hormonal therapy, its mechanism, treatment results, and toxicity profile is presented

Przerzuty do kości: możliwości radioterapii

Bone metastases are the consequence of cancerous disease progress frequently. In metastatic stage they can be present in 14-80% of patients depending on localisation and morphological type. In autopsy study this rate can be even higher up to 70-85%. Patients with bone metastases need a multidisciplinar approach. The consultation by a specialistic group should effect in decision to use analgesics, radiotherapy, surgery, chemotherapy , hormonotherapy and biphosphonates. Radiotherapy is one of the main treatment options of high analgesic effectiveness and quite little burden for patient. It can be applied in every radiotherapy centre within a few hours from the admission to the centre. Onkol. Prak. Klin. 2011; 7, 5: 264&#8211;268Przerzuty do kości są częstym następstwem rozwoju choroby nowotworowej. W stadium przerzutowym w zależności od lokalizacji i typu morfologicznego mogą wystąpić u 14&#8211;80% chorych. W badaniach autopsyjnych ten odsetek jest jeszcze wyższy i może zawierać się w przedziale 70&#8211;85%. Leczenie pacjentów z przerzutami do kości powinno obejmować postępowanie wielodyscyplinarne. Wynikiem konsultacji przeprowadzonej przez zespół specjalistów powinna być decyzja obejmująca zastosowanie w różnej kombinacji leków przeciwbólowych, radioterapii, operacji, chemioterapii, leczenia hormonalnego, bisfosfonianów. Radioterapia jest jedną z istotnych opcji leczenia, charakteryzującą się wysoką efektywnością przeciwbólową przy względnie małej uciążliwości dla pacjenta. Może być praktycznie przeprowadzona w każdym zakładzie radioterapii w przeciągu kilku godzin od chwili zgłoszenia się takiego pacjenta do ośrodka. Onkol. Prak. Klin. 2011; 7, 5: 264&#8211;26

Hormonal therapy combined with radiotherapy in locally advanced prostate cancer

At present radiation therapy and radical prostatectomy are considered to be the treatment of choice for clinical T1-T2 prostate cancer. In a more advanced stage of the disease (T3) 10-year overall survival is observed in approximately 40% of patients treated with conventional radiotherapy. So far only a few methods for improving the efficacy of radiotherapy have been introduced. One of them is a three-dimensional conformal radiotherapy with 3 dimensional treatment planning. These novel methods make it possible to escalate the dose to the target and protect healthy tissue at the same time. The optimal volume of irradiation, total dose, fraction dose, techniques of radiotherapy, and the end points used during the follow-up are open to debate. In recent years a few clinical trials involving hormonal therapy and radiotherapy have been carried out. The most important of these are: RTOG 8307, RTOG 8610, RTOG 9202, and EORTC 22863.In the RTOG 8307 trial the comparison of outcomes of a combined treatment with a matched-control group of patients treated by radiotherapy alone has shown that adding hormonal therapy to radiotherapy resulted in a better outcome. Another trials RTOG 8531 and RTOG 8610 produced benefit due to the implementation of hormonal therapy in radiotherapy. The EORTC trial No. 22863 showed improvement in the 5-year overall survival when hormonal therapy after the completion of radiotherapy was continued for 3 years in the investigational arm. The RTOG 9202 study indicated benefit obtained from 2 years of adjuvant hormonal therapy.The results of these trials have had a substantial impact on the management of locally advanced prostate cancer, but there are still questions that have to be answered. There is no doubt that hormonal therapy is an important component of the management of locally advanced prostate cancer. Still the optimal combination of drugs and the timing of such treatment remains controversial. Considering the potential side effects of a combined treatment on the quality of life of patients and care costs, additional properly designed randomised trials are needed to identify the subgroup of patients who will obtain the greatest benefit. Currently, it can be concluded that in the group of patients with a high risk of relapse by adding hormonal therapy to radiotherapy the outcome of treatment in patients with prostate cancer has improved

Interleukin-6 (IL-6) and C-reactive protein (CRP) concentration prior to total nephrectomy are prognostic factors in localized renal cell carcinoma (RCC)

AbstractBackgroundRadical nephrectomy is the gold standard for treatment of renal cell carcinoma (RCC), but even for localized disease the survival rates are still unsatisfactory. Identification of prognostic factorsl is the basis for future treatment strategies for an individual patient.AimThe aim of our study was to assess the usefulness of the concentration of IL-6 and CRP as prognostic factors in patients after nephrectomy due to localized RCC.Materials and methodsOur prospective study included 89 patients (55 men and 34 women) who had been surgically treated for RCC. The examined group included patients with localized advanced disease (from T1 to T3) with no metastases in lymph nodes (N0), and with no distant metastases (M0). All patients had blood samples drawn three times during the study (one day before surgery, six days after surgery and 6 months after surgery) to evaluate the concentration of CRP and IL-6. In each patient RCC of the kidney was removed during radical nephrectomy. Statistical analysis was conducted using statistica v.7.0.ResultsStatistically significant relationships were found between the concentration of CRP before the operation and OS (p=0.0001). CRP concentration at baseline was statistically significantly correlated with CSS (p=0.0004). The level of IL-6 assessed before the surgery was significantly correlated with survival times such as OS (p=0.0096) and CSS (p=0.0002). The concentration of IL-6 and CRP measured 6 days after surgery and 6 months after surgery were not statistically significantly correlated with survival times.ConclusionsResults of our study showed that elevated levels of IL-6 and CRP in peripheral blood before surgery of RCC were correlated with worse OS and CSS

Benefit of Whole Pelvic Radiotherapy Combined with Neoadjuvant Androgen Deprivation for the High-Risk Prostate Cancer

Aim. To study whether use of neoadjuvant androgen deprivation therapy (N-ADT) combined with whole pelvic radiotherapy (WPRT) for high-risk prostate cancer patients was associated with survival benefit over prostate radiotherapy (PORT) only. Material and Methods. Between 1999 and 2004, 162 high-risk prostate cancer patients were treated with radiotherapy combined with long-term androgen deprivation therapy (L-ADT). Patients were prospectively assigned into two groups: A (N-ADT + WPRT + L-ADT) n = 70 pts, B (PORT + L-ADT) n = 92 pts. Results. The 5-year actuarial overall survival (OS) rates were 89% for A and 78% for B (P = .13). The 5-year actuarial cause specific survival (CSS) rates were A = 90% and B = 79% (P = .01). Biochemical progression-free survival (bPFS) rates were 52% versus 40% (P = .07), for groups A and B, respectively. Conclusions. The WPRT combined with N-ADT compared to PORT for high-risk patients resulted in improvement in CSS and bPFS; however no OS benefit was observed

Radiation-induced lung injury — what do we know in the era of modern radiotherapy?

Radiation-induced lung injury (RILI) that is usually divided into an early radiation-induced pneumonitis (RIP) and late chronic radiation-induced lung fibrosis (RILF) remains a clinically significant toxicity in radiation oncology. Thus, a thorough understanding of underlying molecular mechanisms and risk factors is crucial. This review, focused on patients treated with modern radiotherapy (RT) techniques, describes the different clinical presentations of RIP, with most typical imaging findings and usefulness of pulmonary function tests and laboratory assessment in differential diagnosis. The most critical patient- and treatment-related predictors are summarized and discussed — age and sex, comorbidities, tumour characteristics, concomitant treatment, and RT-plan parameters. The conventional grading scales and contemporary approach to quantitative assessment (radiomics, CT density changes) is described as well as treatment methods