bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substrate effect on low‐field transport properties of La–Pb–Mn–O granular‐type thin films
Authors: Lee Hi Min , Shim In‐Bo , Kim Chul Sung 
Published: May 2004

AbstractThis paper studied the low‐field tunnel‐type transport characteristics of polycrystalline and c‐axis‐oriented La0.7Pb0.3MnO3 (LPMO) thin films. Polycrystalline thin films were fabricated on SiO2/Si(100) substrate (film A), on SiO2/Si substrate with yttria‐stabilized zirconia (YSZ) buffer layer (film B), and on c‐axis‐oriented thin film grown on LaAlO3(001) (LAO) single crystal substrate (film C) using the soft‐chemical deposition method. A YSZ buffer layer acts as a barrier against inter‐diffusion. As a result, it decreases the amount of dead layers generated from the interface and helps to produce qualitative films for application of magnetoresistive elements. The magnetoresistance (MR) ratio was 0.52%, 0.7%, and 0.4% for film A, film B, and film C under the applied field of 500 Oe at 300 K, respectively. The polycrystalline film had denser boundaries than the c‐axis oriented film, i.e., the polycrystalline film gave more effective potential barrier regions than the c‐axis oriented film. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation of boron carbide thin films from reactive sputtering of boron
Authors: Lee K. E. , Kim C. O. , Park M. J. , Kim J. H. 
Published: May 2004

AbstractBoron carbide thin films were prepared by RF magnetron sputtering. The films were deposited onto CoCr/Cr/SiO2/Si(100) substrates with an RF power of 25, 50 and 75 W in the range of 200 °C. The reactive gas was introduced up to 1.5 vol% (CH4/(Ar + CH4)) during deposition, and the resulting composition of the films matched these ratios, as observed by Auger electron spectroscopy. In X‐ray photoelectron spectroscopy, two well‐resolved peaks in C (1s) spectra were observed around 284 eV, indicating C–C bond at 284.5 eV and B–C bond at 283.5 eV. The X‐ray diffraction of these films revealed the amorphous or nanocrystalline characteristics. At the deposition conditions of 75 W, 100 °C and 1.0 vol%, the nano‐indented films were hardened to 16 GPa and the scratched surfaces endured load of 50 N. In the wear test, the coefficient of friction was also measured down to 0.15. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetically and electrically tunable devices using ferromagnetic/ferroelectric ceramics
Authors: Kim Jang‐Yong , Koh Jung‐Hyuk , Song Jae‐Sung , Grishin Alex 
Published: May 2004

AbstractThere has been a growing interest in tunable devices applications such as filters, phase shifters, and resonators. Both of ferromagnetic and ferroelectric materials have strong advantages in the high tunability and stability. Therefore many reports have been published by employing ferrite or dielectric materials for high frequency devices applications. Both of controllable dielectric permittivity and magnetic permeability were considered one of the solutions for impedance matching in tunable devices. In this experiment ferromagnetic/ferroelectric composite ceramics were successfully fabricated without any cracking or shrinkage. Fabricated ferromagnetic/ferroelectric composite ceramic showed ferroelectric properties of P–E hysteresis and magnetic properties of B–H hysteresis loops. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Static and dynamic magnetostrictive properties of polymer‐bonded Fe–Co based alloy composites
Authors: Na S. M. , Kim S. W. , Shin K. H. , Pasquale M. , Sasso C. P. , Lim S. H. 
Published: May 2004

AbstractPolymer‐bonded composites of an Fe–Co based alloy were developed and their magnetostrictive and mechanical properties were characterized. In this work, the static and dynamic magnetostrictive properties as a function of volume fraction of Fe36Co62Ge2 alloy and frequency are characterized. WC powders are especially added to the composites in order to provide increased mechanical properties and extend the high frequency application range. The experimental results for magnetostriction and Young's modulus are in good agreement with those estimated from a uniform strain model. A large Young's modulus of 93.6 GPa and compressive strength of 195 MPa are obtained for the composites with a WC content of 24.5 wt.%. The increase of resonance frequency (fr) as high as 45 kHz is expected from the results of E33. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Curie temperature of ferromagnetic (Ga,Mn)N epitaxial films
Authors: Lee J. M. , Ham M. H. , Myoung J. M. , Chang J. Y. , Han S. H. , Lee W. Y. 
Published: May 2004

AbstractElectron‐mediated ferromagnetism persisting to room temperature has been investigated in epitaxial (Ga,Mn)N films with low Mn concentration grown by plasma‐enhanced molecular beam epitaxy (PEMBE).The experimental value of TC (∼325 K) in the (Ga,Mn)N film with x = 0.3% from the difference (ΔM) between field‐cooled (FC) and zero field‐cooled (ZFC) magnetization curves is found to be lower than the estimated value of TC (∼407 K), obtained by the mean field approximations. The extra‐ordinary Hall effect in the epitaxial (Ga,Mn)N film with x = 0.2% is found to appear in the temperature range 100 K–300 K. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A study of magnetic and optical properties of Cu‐doped ZnO
Authors: Lee Hyeon‐Jun , Kim Bo‐Seong , Cho Chae Ryong , Jeong Se‐Young 
Published: May 2004

AbstractThe ferromagnetism of ZnO‐based magnetic semiconductors has been investigated by theoretical calculation and many kinds of experiments. In the Cu‐doped ZnO system, ferromagnetic ordering by Cu magnetic moments does not exist, but Cu‐doped ZnO can have ferromagnetism due to the distortion of the ZnO‐based structure by Cu doping. In this study, we investigated the magnetic properties of Cu‐doped ZnO and discussed the possible origin of magnetism in this system. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Site occupancy and anisotropy distribution of Al substituted Ba‐ferrite with high coercivity
Authors: Choi Dong Hyeok , An Sung Yong , Lee Sang Won , Shim In‐Bo , Kim Chul Sung 
Published: May 2004

AbstractThe site occupancy and anisotropy distribution of Al substituted BaFe12−xAlxO19 (0.0 ≤ x ≤ 4.0) have been studied with Mössbauer spectroscopy, X‐ray diffraction, and vibrating sample magnetometry. The results suggest that the coercivity, magnetization, and magnetocrystalline anisotropies are closely related to the distributions of Al3+ ions on the five iron sites. Mössbauer spectra indicated that Al3+ ions have a strong preference for the 4f1, 2a and 12k sites. The substitution of Al3+ by Fe3+ in the system causes a drastic reduction of the saturation magnetization while the coercivity first increases to 8.6 kOe, for x = 2.0, and then decreases to 6.9 kOe, for x = 4.0. The origin of the changes in the magnetic properties caused by Al3+ substitution can be attributed to the site preferences. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The control of in‐plane magnetic anisotropy by ion irradiation
Authors: Kim S. H. , Yune J.‐H. , Aeo J.‐T. , Kim T. H. , Shin S. W. , Kim H. B. , Jeong K. , Whang C. N. , Chang G. S. , Chae K. H. 
Published: May 2004

AbstractThe increase of bit density is a critical point in the magnetic storage media. We intend to manipulate the easy axis in ferromagnetic thin films with ion irradiation technique. Co/Pt multilayered films were prepared for the study and then were ion‐irradiated while an external magnetic field was applied to them. In consequence, we get a CoPt alloy film with an in‐plane easy axis and change its direction with an external magnetic field applied during the irradiation. The energetic ion beam let the ferromagnetic film have a new atomic and magnetic structure. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pseudo spin‐valve structures with NiO/Co as a hard magnetic layer
Authors: Dubowik J. , Stobiecki F. , Szymański B. , Gościańska I. , Röll K. , Lee Y. P. 
Published: May 2004

AbstractA key problem in some applications of pseudo spin‐valve structures (PSV) is the choice of appropriate materials for soft and hard ferromagnetic layers and their thickness to ensure a high difference in the switching fields. We show that this can be achieved using a NiO/Co structure as a hard magnetic layer. By varying the thickness of the constituent layers, good symmetrical switching characteristics have been shown in PSV structures with NiO/Co as a hard magnetic layer. The most important features of our PSV structures with suitable selected thickness of particular layers are: a relatively high value of GMR amplitude (up to 9% at RT) due to a possible electron specular reflection at the NiO/Co interfaces, a high coercivity (∼500 Oe) of hard magnetic layer resulted from a specific interaction of a 15 nm thick antiferromagnetic NiO with a 2 nm thick Co layer, nearly symmetrical magnetoresistance transfer curves MR(H) due to negligible unidirectional anisotropy field of NiO/Co bilayer with NiO thickness <15 nm. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhanced ferromagnetism in Co‐doped TiO2 powders
Authors: Cho J. H. , Kim B. Y. , Kim H. D. , Woo S. I. , Moon S. H. , Kim J. P. , Cho Chae Ryong , Joh Y. G. , Kim E. C. , Kim D. H. 
Published: May 2004

AbstractWe studied the structural and magnetic properties of Ti1−xCoxO2 powder samples synthesized by the sol–gel method. In order to study the post annealing effect on the magnetic properties, the same precursor was annealed at 770 K for 5 h in air and in the pressure of 10−6 Torr. In the case of samples annealed in vacuum, enhanced ferromagnetism was observed at room temperature, while only paramagnetic behavior was observed in samples annealed in air. Moreover, the magnetization of the vacuum‐annealed sample sharply decreased around 650 K while measuring in air, but such decrease in the magnetization was almost absent while measuring in He gas up to 750 K. The structural studies showed dominant anatase and minor rutile phases in vacuum‐annealed samples, while an additional nonmagnetic CoTiO3 phase was observed in air‐annealed samples. We attribute the enhanced magnetization in the vacuum‐annealed sample to the oxygen deficiency which prevents the formation of non‐magnetic CoTiO3 complexes. It is also possible that the reduced oxygen environment can promote the clustering of Co‐rich clusters as evidenced by transmission electron microscopy in samples of x = 0.1, thus giving rise to an enhanced ferromagnetic behaviour. However, no direct observation of Co clusters in samples for x ≤ 0.05 was made. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic properties of Co/Ag/Co films grown on Ag(100) nanometer‐scale islands
Authors: Wei D. H. , Yu C. C. , Chou S. C. , Yao Y. D. , Liou Y. , Chin T. S. 
Published: May 2004

AbstractSelf‐assembled Ag(100) islands on Si(100) substrate were fabricated by using the molecular beam epitaxy technique. Co/Ag/Co films were then grown onto Ag films at 100 °C. We have experimentally demonstrated that the magnetic behavior of Co/Ag/Co films is strongly dependent on the thickness and morphology of the Ag(100) islands that serve as a buffer layer. The buffer layer designed to reduce the surface free energy forms isolated pyramidal islands with {111} sidewalls on the Si(100) substrate, and provides feasibility to study the correlation between magnetic properties and interface roughness. Ag islands also play an important role in the magnetoresistance transition of Co/Ag/Co films. The roughened Ag(100) surface facilitates texture growth of Co/Ag/Co films and provides a resultant domain‐wall‐pinning, that in turn contributes to the in‐plane demagnetization factor. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Competition and coexistence in host‐parasite systems: the myxomatosis case
Authors: Aparicio Juan Pablo , Solari Hernán G. , Bonino Never 
Published: May 2004

AbstractCo‐circulation of several strains of parasites has been observed in many host‐parasite systems. However, simple epidemiological models cannot sustain this coexistence. In this work we study the coexistence of viral strains in the myxomatosis case. Myxomatosis, a highly lethal disease of the European rabbit, has been used in Australia and Europe as a biological control of rabbit populations. A few years after its introduction, the original highly virulent strains were almost completely replaced by field strains covering a wide range of virulence. Here, we study several mechanisms that may explain the field observations. First we considered spatial heterogeneity. The establishment of any strain over regions occupied by host populations may delay the spread of any superior competitive virus strain, producing global coexistence in the long term. On the other hand, sub‐populations with different resistance levels in epidemiological contact, as observed in the field, can maintain several different virus strains co‐circulating. The second class of mechanism introduces diversity among hosts of a local population sharing a territory. We considered different classes of host resistance to myxomatosis: belonging to a resistance class is a random fact. Host age‐dependent resistance is also especially considered. These types of population heterogeneity can sustain local coexistence for many years, although exclusion takes place for long enough periods. The concurrent action of both types of mechanisms could explain why the diversity of virus strains is sustained, and the local coexistence. Finally, we briefly discuss the influence of host genetic dynamics in the coevolution of the system.
Adenoviral‐mediated transfer of human BMP‐6 gene accelerates healing in a rabbit ulnar osteotomy model
Authors: Bertone A. L. , Pittman D. D. , Bouxsein M. L. , Li J. , Clancy B. , Seeherman H. J. 
Published: May 2004

AbstractThis study evaluated healing of rabbit bilateral ulnar osteotomies 6 and 8 weeks after surgery in response to percutaneous injection of transgenic adenoviral (Ad) bone morphogenetic protein‐6 (BMP‐6) vector or green fluorescent protein vector control (Ad‐GFP) administered 7 days after surgery compared to untreated osteotomy controls. The amount, composition and biomechanical properties of the healing bone repair tissue were compared among groups and to historical data for intact rabbit ulnae obtained from similar studies at the same institution. Quantitative computed tomography was used to determine area, density and mineral content of the mineralized callus in the harvested ulnae. Maximum torque, torsional stiffness, and energy absorbed to failure were determined at 1.5°/s. Calcified sections of excised ulnae (5 μm) were stained with Goldner's Trichrome and Von Kossa, and evaluated for callus composition, maturity, cortical continuity, and osteotomy bridging. Radiographic assessment of bone formation indicated greater mineralized callus in the ulnae injected with Ad‐hBMP‐6 as early as 1 week after treatment (2 weeks after surgery) compared to untreated osteotomy ulnae (P < 0.006) and Ad‐GFP treated osteotomy ulnae (p < 0.002). Quantitative computed tomography confirmed greater bone area and bone mineral content at the osteotomy at 6 weeks in Ad‐BMP‐6 treated osteotomy as compared to untreated osteotomy ulnae (p < 0.001) and Ad‐GFP treated osteotomy ulnae (p < 0.01). Ad‐BMP‐6 treated osteotomy ulnae were stronger (p < 0.001 and 0.003) and stiffer (p = 0.004 and 0.003) in torsion at 6 weeks than untreated osteotomy ulnae or Ad‐GFP treated osteotomy ulnae, respectively. Maximum torque, torsional stiffness, and energy absorbed to failure were greater in Ad‐BMP‐6 treated osteotomy ulnae compared to their respective untreated contralateral osteotomy ulnae at 8 weeks [p < 0.03]. Maximum torque and torsional stiffness in the Ad‐BMP‐6 treated osteotomy ulnae were not different to intact ulnae values at 6 and 8 weeks. These experiments confirm that BMP‐6 can be potently osteoinductive in vivo resulting in acceleration of bone repair. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Effect of ketoprofen in topical formulation on vascular endothelial growth factor expression and tumor growth in nude mice with osteosarcoma
Authors: Sakayama Kenshi , Kidani Teruki , Miyazaki Tatsuhiko , Shirakata Haruo , Kimura Yoshiyuki , Kamogawa Junji , Masuno Hiroshi , Yamamoto Haruyasu 
Published: May 2004

AbstractOST cells, a low metastatic cell line established from human osteosarcoma, were inoculated under the periosteum of the ossa cranii of nude mice. Four weeks later, tumors were percutaneously treated for an additional 4 weeks with a patch containing either placebo or ketoprofen (KP). In the placebo group, OST cells formed osteoid and invaded the cranial bone. Tumor mass weighed 3.54 g. Approximately 85% of cells within the tumor expressed proliferating cell nuclear antigen (PCNA), indicating that they were proliferating with a high mitotic activity. Many feeder vessels were located within the tumor. The majority of tumor cells expressed intensely vascular endothelial growth factor (VEGF). In the KP group, invasion of OST cells into the cranial bone was suppressed and the tumor mass was 47% of that of the placebo group. Approximately 65% of cells within the tumor were PCNA‐negative, indicating that their growth was arrested. There were considerably fewer feeder vessels within the tumor in the KP group than in the placebo group. Only a small number of cells expressed VEGF. Based on these findings, we concluded that topical administration of KP to nude mice with osteosarcoma inhibited VEGF expression, reduced the development of feeder vessels for supply of nutrients and oxygen, and suppressed tumor growth. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Lymphocyte Subpopulations and Cytokines in Nasal Polyps: Is there a Local Immune System in the Nasal Polyp?
Authors: Bernstein Joel M. , Ballow Mark , Rich Gary , Allen Cheryl , Swanson Mia , Dmochowski Jacek 
Published: May 2004

PURPOSEThe pathogenesis of chronic hyperplastic rhinosinusitis with massive nasal polyposis is still not entirely known. The present study evaluates the lymphocyte subpopulations and their production of cytokines using a technique for detection of intracytoplasmic cytokines by flow cytometry. This information may allow us to determine whether the source of these lymphocytes is from peripheral blood, the common mucosal immune system, or both.METHODSDetection of intracytoplasmic cytokines by flow cytometry was performed using a fluoresceinated monoclonal antibody directed against CD4+ and CD8+ lymphocytes and a rhodaminelabeled intracytoplasmic monoclonal antibody directed against four cytokines. In this way, the percentage of lymphocytes synthesizing TH1 and TH2 cytokines were identified in nasal polyp lymphocytes and the corresponding peripheral blood lymphocytes of 13 patients.RESULTSLymphocytes producing interferongamma and IL‐2, as well as IL‐4 and IL‐5, were found in the nasal polyps, suggesting that the nasal polyp possesses both TH1 and TH2 cytokine expression. There are also significant differences between the percentage of lymphocytes producing these cytokines between nasal polyps and peripheral blood, suggesting that nasal polyp lymphocytes derive from at least another source than only peripheral blood lymphocytes. Statistical analysis of four groups of patients demonstrated that no statistically significant difference in the lymphocyte subpopulations in atopic versus non‐atopic patients, nor aspirin‐intolerant versus aspirin‐tolerant patients. In general, CD8 cells always produce more interferon‐gamma than IL‐2 in both peripheral blood and nasal polyps. In contrast with this data, CD4 cells produce more IL‐2 in the peripheral blood than in nasal polyps.CONCLUSIONSData support the concept that nasal polyp lymphocyte subpopulations may be derived from both the local mucosal immune system as well as from random migration of peripheral blood lymphocytes secondary to adhesion molecules and chemokines, which are known to be present in nasal polyps.
Extended Orbitozygomatic Approach to the Skull Base to Improve Access to the Cavernous Sinus and Optic Chiasm
Authors: Pontius Allison Teresa , Ducic Yadranko 
Published: May 2004

BACKGROUNDThe orbitozygomatic approach to the skull base has evolved over the past century, with a surge in development during the past 20 years. We describe an extension of this technique involving removal of the most inferior portion of the temporal bone to the level of the internal carotid artery as it enters the carotid canal, to further facilitate exposure of tumors in this region.METHODS AND MATERIALSWe performed the extended orbitozygomatic approach in a series of 17 patients with a variety of neoplastic lesions. Our case series was reviewed in a retrospective fashion, and our surgical approach is described. The approach is performed safely and effectively by using the spine of the sphenoid and middle meningeal artery as landmarks and then resecting the temporal bone from the temporal craniotomy site to the carotid canal.RESULTSThe extended orbitozygomatic approach has been performed at our institution over the past 6 years and has provided significantly improved access to this region of the skull base, facilitating tumor extirpation in our patient population without an increase in complications.CONCLUSIONSThe extended orbitozygomatic approach further improves exposure and facilitates surgical dissection in patients with neoplasms of the cavernous sinus, sellar region, interpeduncular region, and upper clivus. The improved access without an increase in complications supports the inclusion of the extended orbitozygomatic approach in the armamentarium of the skull base surgeon.
Influences of Allergic Rhinitis on Sleep
Authors: Ferguson Berrylin J. 
Published: May 2004

BACKGROUNDAllergic rhinitis is classically characterized by sneezing, pruritus, rhinorrhea, and nasal congestion. These symptoms can lead to impaired nocturnal sleep, and this impairment results in daytime fatigue and somnolence, reducing both learning and work efficiency and decreasing quality of life.STUDY DESIGNIn addition, the mediators of AR, including histamine, leukotrienes, cytokines, and prostaglandins, may play a role in sleep regulation and, thus, may be directly involved in this impairment independent of nasal obstruction. Recumbency and/or diurnal variation augments turbinate swelling, causing nasal blockage during nocturnal sleep. Medications directed toward reversal of nasal congestion often concomitantly work through suppression of inflammatory mediators and constitute the primary therapy for sleep disturbance associated with allergic rhinitis. Some pharmaceutical interventions that reduce nasal congestion have adverse effects on sleep. Decongestants effectively reduce nasal congestion but frequently produce stimulatory effects and even insomnia. Antihistamines reduce sneezing and pruritus, but are less effective in relieving congestion. Earlier, “first‐generation” antihistamines are associated with significant sedation. They also have anticholinergic properties, which can cause dry mouth and make mouth breathing even more uncomfortable in the allergic individual with nasal obstruction. The absence of anticholinergic properties in second‐generation, largely nonsedating antihistamines limits their efficacy in rhinorrhea. Azelastine, a topical antihistamine, significantly reduces rhinorrhea and congestion and improves subjective sleep quality, but is also associated with increased sedation. Intranasal corticosteroids and oral leukotriene receptor antagonists effectively reduce rhinorrhea, congestion, and inflammatory mediators.CONCLUSIONSThe efficacy of these medications at improving subjective sleep quality has been established through multiple randomized, double‐blind, placebo‐controlled clinical trials.