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  • 2000-2004  (453)
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  • 11
    Digitale Medien
    Digitale Medien
    Parametrically forced pattern formation (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Chaos 11 (2001), S. 52-56 
    Details
    ISSN: 1089-7682
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Pattern formation in a nonlinear damped Mathieu-type partial differential equation defined on one space variable is analyzed. A bifurcation analysis of an averaged equation is performed and compared to full numerical simulations. Parametric resonance leads to periodically varying patterns whose spatial structure is determined by amplitude and detuning of the periodic forcing. At onset, patterns appear subcritically and attractor crowding is observed for large detuning. The evolution of patterns under the increase of the forcing amplitude is studied. It is found that spatially homogeneous and temporally periodic solutions occur for all detuning at a certain amplitude of the forcing. Although the system is dissipative, spatial solitons are found representing domain walls creating a phase jump of the solutions. Qualitative comparisons with experiments in vertically vibrating granular media are made. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1350454
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  • 12
    Digitale Medien
    Digitale Medien
    Admittance spectroscopy of efficient CuInS2 thin film solar cells (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 5474-5481 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Thermal admittance spectroscopy is applied to characterize the trap properties of high-efficiency CuInS2/CdS/ZnO thin film solar cells. To that aim, the capacitance spectrum is examined in detail. Nontrap capacitance contributions like freeze-out of free carriers and series resistance are discussed. The dependence of the resistance on the sample area is used to identify its physical origin. Simulation results of a transmission line model are in good agreement with the spreading resistance of the ZnO window layer. Defect spectra, i.e., the distribution of the deep trapping states in the band gap, are extracted from the admittance spectra, using a method established by T. Walter, R. Herberholz, C. Müller, and H. W. Schock [J. Appl. Phys, 80, 4411 (1996)]. Arrhenius data of the traps are drawn best from the spectrum of conductance versus temperature. The defect spectra do not depend on the buffer layer. Generally, they show a high constant background trap density with some broad peaks. Two new trap levels at 0.3 and 0.5 eV are found, confirmed by deep level transient spectroscopy and identified as majority carrier traps in the bulk of the p-type CuInS2 absorber. An increasing density of the trap at 0.5 eV correlates with a decreasing open-circuit voltage. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1312838
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  • 13
    Digitale Medien
    Digitale Medien
    Stiffness analysis for the micromagnetic standard problem No. 4 (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 7600-7602 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: In this article solutions to micromagnetic standard problem No. 4, a 500-nm×125-nm-wide NiFe film, are presented. A three-dimensional-finite element simulation based on the solution of the Gilbert equation has been used. The simulations show that two different reversal mechanisms occur for the two different applied fields. For a field at 170° counterclockwise from the saturation direction there is a nonuniform rotation of magnetization towards the direction of the applied field, with the magnetization at the ends rotating faster than the magnetization in the center. For a field at 190° counterclockwise from the saturation direction the magnetization at the ends and in the center rotate in opposite directions leading to the formation of a 360° wall after 0.22 ns associated with a peak in the exchange energy. Moreover, the time for the magnetization component parallel to the long axis to cross the zero is 0.136 and 0.135 ns for field 1 and field 2, respectively. The stiffness of the problem has been investigated solving the system of ordinary differential equations with a nonstiff method (Adams) and a stiff one (backward differentiation formula, BDF). For the measure of stiffness the ratio of the total number of time steps (nst) taken by the two solvers, that is nst(Adams)/nst(BDF), has been used. This ratio is 0.784 for field 1 and 0.593 for field 2, which means that the nonstiff method (Adams) uses larger time steps than the stiff method (BDF) and consequently the systems are not stiff. The average time step for the Adams method was 0.2 ps for both fields. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1355355
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  • 14
    Digitale Medien
    Digitale Medien
    Active length control of two phase locked CO2 lasers with a digital signal processor (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 3298-3305 
    Details
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Two CO2 lasers are phase locked together by injection locking, where radiation between the two lasers is exchanged using a copper prism as a beam folding device in the resonators. Extraction of the output radiation is achieved by a common output coupler. As this method is only utilizing reflective optics (except for the output coupler), it is also practical as a technique for phase-locking lasers with powers in the multikilowatt range. Single frequency oscillation is only achieved if the lengths of both resonators are within a so-called locking range. This can only be fulfilled if the length of one resonator is actively controlled. The method of detection of the phase difference between the lasers and actively controlling the length of one resonator is presented as well as its implementation into a digital signal processor. Stable phase locked operation is achieved and proved through detection of twice the intensity in the far field in the phase-locked regime. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1288263
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  • 15
    Digitale Medien
    Digitale Medien
    Highly charged ion based time-of-flight emission microscope (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 2077-2081 
    Details
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: An emission microscope using highly charged ions as the excitation source has been designed, constructed, and operated. A novel "acorn" objective lens has been used to simultaneously image electron and secondary ion emission. A resistive anode-position sensitive detector is used to determine the x–y position and time of arrival of the secondary events at the microscope image plane. Contrast in the image can be based on the intensity of the electron emission and/or the presence of particular secondary ions. Spatial resolution of better than 1 μm and mass resolution m/Δm of better than 400 were demonstrated. Background rejection from uncorrelated events of greater than an order of magnitude is also achieved. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1150582
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  • 16
    Digitale Medien
    Digitale Medien
    100
An Open, Randomised, Explorative, Phase II, Investigation Comparing Enamel Matrix Derivative Proteins (EMD) and Control In Patients With Pressure Ulcer Stage II (2004)
    Oxford, UK; Malden, USA : Blackwell Science Ltd/Inc.
    Wound repair and regeneration 12 (2004), S. 0 
    Details
    ISSN: 1524-475X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background: Enamel Matrix Derivative proteins (EMD) have been used as local adjunct to periodontal surgery in more than 600.000 patients. EMD is approved in Europe, USA and Japan as a medical device class III. There have been no negative reports concerning the safety of the EMD. This is the first reported controlled investigation in a series of ongoing investigations on EMD application in chronic wounds and burns. Aim of the study: The investigation was designed as an open randomised investigation with EMD (30 mg/ml) or vehicle control that consists of propylene glycol alginate (PGA) only. Ten patients were planned to be included. Male or female patients were 〉18 years of age and had had pressure ulcer present for more than 1 month. Patients with controlled diabetes were also included in the study. Patients with sacral pressure ulcer were to be excluded. EMD or vehicle control was applied weekly for up to 8 weeks. All patients received a secondary dressing (Mepilex® Border). Ulcer status and area were measured at week 0, 2, 4, 6, and 8. The primary objective was to measure the wound area and the percentage of viable/non-viable tissue. The secondary objectives were to evaluate ulcer tissue in biopsies taken before application (baseline) and at last visit. Tissue morphology was evaluated on haematoxylin-eosin-stained sections and the presence of EMD, selected growth factors, proliferating cells and myofibroblasts in tissue sections stained with monoclonal antibodies.Regulatory authority and Ethical committee in Belgium approved the investigation. Results: At the time of the abstract submission, results are not final. The histology and immunohistochemical evaluations will be performed November/December 2003.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1067-1927.2004.0abstractct.x
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  • 17
    Digitale Medien
    Digitale Medien
    Clinical Breast Examination: What Can Be Recommended for Its Use to Detect Breast Cancer in Countries with Limited Resources? (2003)
    Oxford, UK : Blackwell Science Inc
    The @breast journal 9 (2003), S. 0 
    Details
    ISSN: 1524-4741
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract: Clinical breast examination (CBE) refers to the traditional technique of physical examination of the breast by a health care provider. The examination comprises both systematic inspection and palpation of the nipple, breast, and lymph-draining regions in the axillae and supraclavicular and infraclavicular fossae. CBE is the least studied of the modalities for breast cancer screening. Whereas recommendations for mammography and breast self-examination (BSE) can be based on the findings of randomized screening trials, there have been no randomized trials of CBE alone on which to base recommendations. However, there is considerable indirect evidence from studies that CBE can be recommended as a method for detecting breast cancer for public health benefit. The examination by itself is inexpensive, as no special equipment is required. It is easy to perform, it can be readily taught to health care providers, and it can be offered ubiquitously. CBE should be part of any program for early detection of breast cancer worldwide, provided that follow-up medical and oncology care is available. Physicians and women should be informed about the advantages and disadvantages of this modality, especially as there are no data from randomized trials about the contribution of CBE in detecting breast cancer at an early stage and the absolute benefit of this modality in reducing breast cancer mortality and improving quality of life. Further research on CBE should be promoted, especially in countries with limited resources, to evaluate its efficacy and effectiveness in relation to age, ethnicity, and race. 
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1524-4741.9.s2.10.x
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  • 18
    Digitale Medien
    Digitale Medien
    Quality of Life Following Breast-Conserving Therapy or Mastectomy: Results of a 5-Year Prospective Study (2004)
    Oxford, UK : Blackwell Science Inc
    The @breast journal 10 (2004), S. 0 
    Details
    ISSN: 1524-4741
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract:  There are many conflicting results in the literature comparing quality of life following breast-conserving therapy (BCT) and mastectomy. This study compared long-term quality of life between breast cancer patients treated by BCT or mastectomy in three age groups. Patients (n = 990) completed a quality of life survey, including the European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire (EORTC QLQ-C30), at regular intervals over 5 years. In the cross-sectional data, mastectomy patients had significantly (p 〈 0.01) lower body image, role, and sexual functioning scores and their lives were more disrupted than BCT patients. Emotional and social functioning and financial and future health worries were significantly (p 〈 0.01) worse for younger patients. There were no differences in body image and lifestyle scores between age groups. There was also no interaction between age and surgery method. Even patients ≥70 years of age reported higher body image and lifestyle scores when treated with BCT. The repeated measures analysis indicated that four functioning scores, half the symptom scores, future health, and global quality of life improved significantly (p 〈 0.01) over time. All these variables increased significantly for BCT patients and those 50 to 69 years of age. Body image, sexual functioning, and lifestyle disruption scores did not improve over time. BCT should be encouraged in all age groups. Coping with appearance change should be addressed in patient interventions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1075-122X.2004.21323.x
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  • 19
    Digitale Medien
    Digitale Medien
    Age-dependency of insulin-like growth factors, insulin-like growth factor–binding proteins, and acid labile subunit in plasma and wounds of surgical patients (2002)
    Malden, USA : Blackwell Science Inc
    Wound repair and regeneration 10 (2002), S. 0 
    Details
    ISSN: 1524-475X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Wound problems are common in the elderly. We hypothesized that age-related decrements in blood levels of components of the insulin-like growth factor (IGF) system are reflected in the wound environment. In this prospective, observational study IGF-I, IGF-II, IGF-binding protein-2, IGF-binding protein-3, and acid labile subunit were measured by immunoassays in the wound fluid and plasma of young (23.5 ± 3.3 years) and elderly (78.9 ± 6.2 years) patients before and daily for 4 days after elective surgery. IGFs, IGFBP-3, and acid labile subunit in plasma were significantly lower in the elderly group (p 〈 0.0001). The decrements of these proteins in plasma were reflected in corresponding decrements of 25–70% in the wound fluid of elderly patients (p 〈 0.0001). Additionally, bioavailability of IGF-I was less in the aged. The IGF parameters in the wound displayed a constant ratio with those of blood, suggesting that blood contributes a major share of the IGF that enters the wound during the initial phase of healing. The current data adds to accumulating evidence that a decline in the IGF system in aged patients contributes to the healing deficits observed in the elderly. (WOUND REP REG 2002;10:360–365)
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1524-475X.2002.10604.x
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  • 20
    Digitale Medien
    Digitale Medien
    Soft X Rays: The Alternative? (2000)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of interventional cardiology 13 (2000), S. 0 
    Details
    ISSN: 1540-8183
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: SummaryIntravascular radiation therapy to prevent restenosis remains promising and is currently undergoing large randomized clinical trials. Intravascular brachytherapy sources include beta particles, gamma rays, and now, soft X rays. The presented, but unpublished data from the START trial indicate that beta radiation is effective in the treatment of in-stent restenosis. However, the limited range of beta particles in tissue increase the complexity for treating large arteries, more dose asymmetry with imperfect centering, and the potential for shadowing when treating calcified or stented arteries. These dosing problems are avoided with high energy gamma rays, but at a cost of increased radiation exposure. Soft X rays generated by high voltage, miniaturized x-ray tubes may be turned off at will, pose little radiation exposure risk to medical personnel, provide a satisfactory dose profile to the artery, and do not require special use licensing. The higher LET and RBE for soft X rays indicates that lower doses may be as effective. Soft x-ray sources will permit a new therapy to enter the expanding discipline of vascular brachytherapy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1540-8183.2000.tb00324.x
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