bluuebunny/crossref_metadata_2025 huggingface dataset:
Polydispersity effects and the interpretation of polymer adsorption isotherms
Authors: Stuart M. A. Cohen , Scheutjens J. M. H. M. , Fleer G. J.
Published: August 2005

In many cases, polymer adsorption is studied by measuring adsorption isotherms. Quite often it is found that the results are at variance with theoretical predictions. However, usually these adsorption isotherms are interpreted in terms of a single polymeric solute. Most polymers used in experimental studies are polydisperse and should be treated as mixtures. It is well established that the larger molecules in such mixtures adsorb preferentially over the smaller ones. In this paper we show that many discrepancies between polymer adsorption theory and experiment (e.g., the rounded shape of isotherms, the dependence of the adsorbance on adsorbent concentration, and the lack of desorption upon dilution) can be attributed to polydispersity. A quantitative analysis enables us to calculate isotherms for a polymer of arbitrary molecular weight distribution, provided the dependency of the plateau adsorbance on molecular weight is known. Experiments supporting the theory are reported. The fact that polymers do not desorb upon dilution with solvent is often regarded as a proof that polymer adsorption is irreversible. We show that, if a polydisperse sample is in equilibrium with an adsorbing surface, no detectable desorption may take place upon dilution. Therefore, the adsorption of polymers might well be reversible, even if desorption experiments would indicate apparent irreversibility.
Anisotropy of dielectric relaxation in crystal form II of poly(vinylidene fluoride)
Authors: Miyamoto Yoshihisa , Miyaji Hideki , Asai Kenjiro
Published: August 2005

The anisotropy of the crystalline relaxation (α relaxation) in oriented poly(vinylidene fluoride) in crystal form II has been studied. The dielectric increment Δε is analyzed on the basis of the two‐site model. A linear relation between Δε/χξ and cos2θ is obtained, where χ is the degree of crystallinity, ξ is the ratio of the internal field to the applied field, and θ is the angle between the applied electric field and the molecular axis. The dipole moment changes direction only along the molecular axis in the relaxation in crystal form II; the molecular motion cannot be explained by chain rotation around the molecular axis. Possible models for the α relaxation are proposed: change in conformation with internal rotation can occur in the crystalline chains, and defects in the crystalline regions play an important role in the α relaxation.
Properties of solution‐grown crystals of fractions of isotactic polypropylene with different degrees of stereoregularity
Authors: Martuscelli Ezio , Pracella Mariano , Zambelli A.
Published: August 2005

Solution‐grown crystals of fractions of isotactic polypropylene (IPP) with different degrees of stereoregularity have been obtained by isothermal crystallization from α‐chloronaphthalene, using a self‐seeding technique. Electron micrographs of samples, crystallized under the same undercooling, show that, with decreasing fraction of isotactic pentads, the perfect rectangular shape of the single crystal is lost and the presence of more complex morphologies is increasingly observed. The equilibrium dissolution temperature Td of IPP fractions, from polymers prepared with a titanium based catalyst, decreases linearly with decreasing percentage of isotactic pentads. An extrapolated value of 171°C is obtained for the equilibrium dissolution temperature of a crystal of IPP with 100% isotactic pentads, i.e., an IPP crystal free of configurational defects. The melting temperature T′m and the apparent enthalpy of fusion ΔH of crystallized and annealed crystal aggregates have been determined by differential calorimetry. The equilibrium melting temperature Tm also depends greatly upon the isotactic pentad concentration. For 100% concentration the extrapolated value of Tm is 181°C. Tm decreases about 1°C per 1% decrease in the isotactic pentad population. The observed equilibrium melting and dissolution temperature depression does not follow the predictions of the Flory equation for copolymer crystallization. In fact, the effect of decreasing probability of isotactic sequence propagation is to depress Td and Tm much more rapidly. The apparent enthalpy of fusion of both solution‐grown crystals and melt‐recrystallized samples decreases with an increase in the number of configurational impurities along the chain. For the most stereoregular fraction the average length of isotactic stereoblocks has been compared with the lamellar thickness of solution‐grown lath‐shaped single crystals.
Crystallization characteristics of polymer blends. I. Polyethylene and polystyrene
Authors: Aref‐Azar Ahmad , Hay James N. , Marsden Brian J. , Walker Neil
Published: August 2005

Blends of polyethylene and polystyrene have been prepared to study the effect of the morphology on their crystallization characteristics since the polymers are known to phase separate. The polymer component present in least amount formed a dispersed phase of discrete spherical particles whose number and size altered with blend composition. However, close to 50% composition cylindrical rods of polyethylene dispersed in polystyrene were observed. With polyethylene in excess the kinetics of crystallization were insensitive to the morphology, but with polyethylene present as the dispersed phase they became dependent on the size and number of the spheres, and in particular on the nucleation density. When the number of spherical particles exceeded that of heterogeneous nuclei, larger supercoolings, and so presumably homogeneous nucleation, were required for crystallization to develop further. The degree of crystallization of the blends then became dependent on the temperature of crystallization rather than on time, and the isothermal crystallization appearing to be instantaneous.
Effects of heat and pressure on intercalation structures of isobutylene‐isoprene rubber/clay nanocomposites. I. Prepared by melt blending
Authors: Liang Yu‐Rong , Ma Jun , Lu Yong‐Lai , Wu You‐Ping , Zhang Li‐Qun , Mai Yiu‐Wing
Published: August 2005

In this work, the effects of heat and pressure on intercalated structures of isobutylene‐isoprene rubber/clay nanocomposites (IIRCNs) prepared by melt blending were investigated. Not only the local intercalated structures were monitored by wide‐angle X‐ray diffraction, but also the spatial distributions of intercalated structures were observed by transmission electron microscope. The experimental result reveals that the intercalated structures and their spatial distributions in the matrix are extensively altered by the thermal treatment at atmospheric or higher pressure. The possible microstructural models for untreated and treated IIRCNs were put forward. The observed phenomena were interpreted from the viewpoints of thermodynamics and kinetics theories as well as the feature of rubber. Finally, guidelines were proposed for designing curing system to achieve desired intercalated/exfoliated morphology. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2653–2664, 2005
Characterization of ZnO/diamond SAW devices elaborated on the smooth nucleation side of MPACVD diamond
Authors: Le Brizoual L. , Lamara T. , Sarry F. , Belmahi M. , Elmazria O. , Bougdira J. , Remy M. , Alnot P.
Published: August 2005

We designed a SAW filter in this work by combining the piezoelectric ZnO film with a freestanding double layer diamond film deposited using CH4–H2 pulsed MPACVD process through two growth stages. The AFM measurements on the nucleation side of the diamond film has shown that this side is smooth enough to perform photolithography process in the SAW device elaboration, while the good quality of the diamond film produced on this side has been confirmed through Raman spectroscopy.

Furthermore, the ZnO films having their c axis perpendicular to the substrate were deposited using reactive magnetron sputtering under the optimal experimental conditions found from XRD measurements. In the SAW device elaboration on this ZnO/bilayer diamond structure, aluminium interdigital transducers (IDTs) were developed by conventional contact UV photolithography on the nucleation side of the freestanding diamond. The frequency response of the device presents harmonics of the acoustic wave modes propagating in the smooth diamond nucleation side. The good agreement obtained between the experimental and theoretical frequency responses attests that the elastic properties of the ZnO and the diamond are similar to those of the single crystal assumed in the theoretical study. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Silicon incorporation in CVD diamond layers
Authors: Barjon J. , Rzepka E. , Jomard F. , Laroche J.‐M. , Ballutaud D. , Kociniewski T. , Chevallier J.
Published: August 2005

The silicon incorporation in diamond is an important issue as silicon is widely used as a substrate for the growth of polycrystalline thin films. Incorporated silicon impurities are suspected to come from the hydrogen etching of the silicon substrate. To clearly establish this point we introduced a solid source of silicon during the growth of a homoepitaxial diamond layer on a HPHT diamond substrate. A quantitative SIMS analysis revealed concentrations of silicon up to 3 × 1019 cm–3 in the diamond layer. Then we propose a scenario for the contamination of polycrystalline diamond grown on silicon substrates: after nucleation, the progressive paving of the silicon surface by 3D grains causes a fast decrease of its incorporation. At coalescence, the silicon substrate is completely covered by a 2D diamond film and the silicon concentration in diamond reaches a residual level. The investigated MPCVD and HFCVD diamond layers grown on silicon substrates present comparable features. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characteristics of excitonic emission in diamond
Authors: Okushi Hideyo , Watanabe Hideyuki , Kanno Shokichi
Published: August 2005

Detailed characteristics of excitonic emission in diamond have been studied by theoretical considerations taking into account the indirect semiconductor properties to calculate precise simulated spectra of the excitonic emission. The simulated excitonic emission spectra agree well with the observed spectra in our high quality diamond thin films, showing that the chemical potential of the exciton gas can be reduced precisely. The results indicate that (1) the characteristics of exciton emission of indirect semiconductors are much difference than those of direct ones, (2) exciton collisions cause line broadening and (3) quantum statistical (Bose–Einstein statistics) properties appear for highly excited exciton densities in diamond. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Negative electron affinity on hydrogen terminated diamond
Authors: Takeuchi D. , Ri S.‐G. , Kato H. , Nebel C. E. , Yamasaki S.
Published: August 2005

Total photoyield spectroscopy (TPYS) is applied to characterize the surface electronic properties of p‐ and n‐type chemical‐vapour‐deposited (111) homoepitaxial diamond films with hydrogen terminated (H‐terminated) surfaces. All experiments on H‐terminated high quality diamond show the same threshold energy of 4.4 eV and comparable spectra in the regime 4.4–5.5 eV. A H‐terminated intrinsic IIa (100) sample also show the same result. The onset of electron emission at 4.4 eV on p‐, intrinsic and n‐type diamond indicates that Fermi levels do not affect the sub‐band spectra. Obviously, direct excitation of valence‐band electrons into the vacuum takes place in the close vicinity of the surface. If we assume a transition from valence band maximum the threshold energy of 4.4 eV gives a negative electron affinity (NEA) of –1.07 eV (Eg ∼ 5.47 eV). TPYS therefore allows a precise and direct detection of the NEA of H‐terminated diamond. It is interesting that the expected rise of photoyield as NEA in the regime hv > 5.47 eV is missing in n‐type diamond. We attribute this to a surface space charge region due to ionized phosphorus atoms. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterisation of single crystal CVD diamond particle detectors for hadron physics experiments
Authors: Pomorski M. , Berdermann E. , Ciobanu M. , Martemyianov A. , Moritz P. , Rebisz M. , Marczewska B.
Published: August 2005

Characterisation results from a single‐crystal CVD diamond detector are reported, which is under development for heavy‐ion particle identification and minimum‐ionizing particles timing in nuclear physics experiments. The charge collection efficiency is about 100%, never obtained from polycrystalline CVD‐diamond detectors. An energy resolution of 20 keV (ΔE/E ≈ 0.004) is achieved using a mixed nuclide α‐source, which is comparable to the energy resolution of silicon pin diode detectors. Using low impedance broadband electronics and a ToF technique, where holes or electrons drift separately inside the diamond bulk, the saturation velocity, mobility and lifetime of both charge carriers are estimated. In addition the thermoluminescent properties of the new material are discussed in comparison to polycrystalline diamond. A much lower density of trapping centres has been found for single‐crystal CVD diamond. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of RIE treatments for {111} diamond substrates on the growth of P‐doped diamond thin films
Authors: Tavares Céline , Koizumi Satoshi , Kanda Hisao
Published: August 2005

The reactive ion etching (RIE) procedures were applied for mechanically polished {111} diamond substrates surfaces using oxygen and hydrogen gas sources to improve the crystalline quality of chemical vapor deposited (CVD) n‐type diamond layers. The growth of phosphorus‐doped films was performed on RIE treated diamond substrates by microwave plasma‐assisted CVD using phosphine (PH3) as a doping source. Cathodoluminescence (CL) measurements of the epilayer clearly revealed a significant decrease of the intensity of band‐A emission for samples with RIE pre‐treatment. The Hall mobility was also improved reproducibly for all the RIE pre‐treated samples. It was found that the RIE treatment of diamond {111} substrate is effective to obtain high quality n‐type diamond thin films reproducibly. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Using symbolic computing in building probabilistic models for atoms
Authors: Guiasu Silviu
Published: August 2005

This article shows how symbolic computing and the mathematical formalism induced by maximizing entropy and minimizing the mean deviation from statistical equilibrium may be effectively applied to obtaining probabilistic models for the structure of atoms, using trial wave functions compatible with an average shell picture of the atom. The objective is not only to recover the experimental value of the ground state mean energy of the atom, but rather to better approximate the unknown parameters of these trial functions and to calculate both correlations between electrons and the amount of interdependence among different subsets of electrons of the atoms. The examples and numerical results refer to the hydrogen, helium, lithium, and beryllium atoms. The main computer programs, using the symbolic computing software MATHEMATICA, are also given. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Maltotriose utilization in lager yeast strains: MTT1 encodes a maltotriose transporter
Authors: Dietvorst J. , Londesborough J. , Steensma H. Y.
Published: August 2005

Maltotriose is the second most abundant fermentable sugar in wort and, due to incomplete fermentation, residual maltotriose in beer causes both quality and economic problems in the brewing industry. To identify genes that might improve utilization of maltotriose, we developed a library containing genomic DNA from four lager strains and a laboratory Saccharomyces cerevisiae strain and isolated transformants that could grow on YP/2% maltotriose in the presence of 3 mg/l of the respiratory inhibitor antimycin A. In this way we found a gene which shared 74% similarity with MPH2 and MPH3, 62% similarity with AGT1 and 91% similarity with MAL61 and MAL31, all encoding known maltose transporters. Moreover, the gene shared an even higher similarity (98%) with the uncharacterized Saccharomyces pastorianus mty1 gene (M. Salema‐Oom, unpublished; NCBI Accession No. AJ491328). Therefore, we named the gene MTT1 (mty1‐like transporter). We showed that the gene was present in four different lager strains but was absent from the laboratory strain CEN.PK113‐7D. The ORF in the plasmid isolated from the library lacks 66 base pairs from the 3′‐end of MTT1 but instead contains 54 bp of the vector. We named this ORF MTT1alt (NCBI Accession No. DQ010174). 14C‐Maltose and repurified 14C‐maltotriose were used to show that MTT1 and, especially, MTT1alt, encode maltose transporters for which the ratio between activities to maltotriose and maltose is higher than for most known maltose transporters. Introduction of MTT1 or MTT1alt into lager strain A15 raised maltotriose uptake by about 17% or 105%, respectively. Copyright © 2005 John Wiley & Sons, Ltd.
A PMR1‐like calcium ATPase of Aspergillus fumigatus: cloning, identification and functional expression in S. cerevisiae
Authors: Soriani F. M. , Martins V. P. , Magnani T. , Tudella V. G. , Curti C. , Uyemura S. A.
Published: August 2005

The understanding of the controlling factors of calcium homeostasis in Aspergillus fumigatus is very poor, although this ion is involved in several important events of these particular cells. We have cloned, identified and expressed for functional complementation a PMR1‐like Ca2+‐ATPase gene from A. fumigatus. The Afpmr1 gene encodes a protein of 1061 deduced amino acids, containing all the conserved subdomains found in other P‐type ATPases: the phosphatase region, phosphorylation site, FITC labelling site, ATP binding domain; E386, N871, D875 amino acid residues for calcium ion interaction and Q880, a residue that alters ion selectivity in PMR1. The expressed AfPMR1 in S. cerevisiae K616 strain functionally complemented the deficient growth in EGTA (5–20 mM)‐ and MnCl2 (4 mM)‐containing medium. These results demonstrate the first evidence of a Ca2+‐ATPase in A. fumigatus and strongly suggest a role for this enzyme in calcium and manganese homeostasis. Copyright © 2005 John Wiley & Sons, Ltd.
Glucose Intolerance Modifies the Inflammatory Response After Intestinal Ischemia‐Reperfusion
Authors: Garcia‐Perez Juan C. , Arias‐Diaz Javier , Vara Elena , Balibrea Jose L.
Published: August 2005

Streptozotocin administration in newborn rats (nSTZ‐rats) leads to adults with mild insulin deficiency and normoglycemia, and is accepted as a model of type 2 diabetes. We examined possible differences in the production of inflammatory mediators between healthy and nSTZ‐rats after ischemia‐reperfusion (I‐R). Two‐month‐old control and nSTZ‐rats were randomly separated into control and intestinal I‐R groups. After reperfusion, samples were obtained from the portal vein (PV) infrahepatic cava vein (ICV), suprahepatic cava vein (SCV), jejunal wall, and pancreas. Nitric oxide (NO), lipid hydroperoxides (LPO), tumor necrosis factor alpha (TNF‐α), 60 kDa receptor (sTNF‐R1), 80 kDa (sTNF‐R2), and intercellular adhesion molecule‐1 (ICAM‐1), were determined. After I‐R, nSTZ‐rats showed increased plasma concentrations of LPO, NO, ICAM‐1 (0.5141 ± 0.083 vs 0.024 ± 0.003, ICV; 0.574 ± 0.075 vs 0.023 ± 0.003, SCV; 0.528 ± 0.067 vs 0.027 ± 0.003 PV; ng/ml), TNF‐α (42.4 ± 5.7 ICV, 248.4 ± 28.2 SCV, and 33.6 ± 4.0 PV. In n STZ‐rats, vs 4.36 ± 0.57, 4.74 ± 0.77, and 3.16 ± 0.32, respectively, in control rats; pg/ml), and sTNF‐R1. Both TNF‐α and NO plasma levels were higher in SCV than in ICV and PV after I‐R. In addition, after I‐R, jejunal wall of nSTZ‐rats showed an increase of TNF‐α IL‐1, and IL‐10 levels. A pre‐existing state of glucose intolerance intensifies the inflammatory response after intestinal I‐R.
Do Germans Keep Patients Too Long in Hospital? A Prospective Randomized Trial
Authors: Dotzenrath Cornelia M. E. , Cupisti Kenko , Raffel Andreas , Aust Birgit , Yang Quh , Krüger Björn , Ohmann Christian , Röher Hans Dietrich , Goretzki Peter E.
Published: August 2005

Cost‐effectiveness reduces hospital stay for all patients with thyroid surgery but lacks information on medical comparability and patients’ fulfilled expectations. The aim of this study was to assess if a hospital stay of 2 days after thyroid surgery had a negative influence on the medical quality or on health‐related quality of life. In a controlled prospective randomized trial with 238 patients, a postoperative hospital stay of 2 days was compared to one longer than 2 days. The postoperative medical investigation included serum calcium levels, laryngeal nerve function, and suction drainage volume. Health‐related quality of life was assessed on the day of admission before the operation and again 14 days after discharge. Fourteen days after discharge patients were also asked about their subjective health. Despite the study design, it was necessary, for ethical reasons, to let the patients decide when to leave the hospital. In the 2‐day study group, 56.6% of the patients preferred hospitalization for more than 2 days (most choosing 3 days). Medical reasons were hyperthyroidism (p < 0.02) and postoperative hypocalcemia (p < 0.03). In the control group 28% left the hospital after 2 days. Only 35% of the patients left the hospital at the second postoperative day, but 60% of these patient supported this shorter hospitalization. Health‐related quality of life and self‐rated health was significantly higher in patients leaving the hospital on the second postoperative day. A 2‐day hospital stay after thyroid surgery is possible and does not show medical or health‐related quality of life disadvantages in patients with an uncomplicated postoperative course who consider themselves healthy.
A New Approach to Accurate Diagnosis of Acute Appendicitis
Authors: Tzanakis Nikolaos E. , Efstathiou Stamatis P. , Danulidis Kecaris , Rallis Georgios E. , Tsioulos Dimitrios I. , Chatzivasiliou Anthimos , Peros Georgios , Nikiteas Nikolaos I.
Published: August 2005

This study aimed (1) to develop a simple scoring system incorporating ultrasound (US) examination and clinical or laboratory predictors for increasing diagnostic accuracy in acute appendicitis (AA), and (2) to evaluate the performance of the scoring system as compared to that of previous models. Fifteen variables including US assessment for patients admitted with suspected AA were considered in multivariate analysis using the finding of AA at operation as the end point (internal study). The new score, together with 11 previous ones, was applied to a prospective independent population of subjects with suspected AA, and the respective performances were compared (external validation study). Among 303 patients (170 males, mean age 28.3 ± 13.3 years) of the internal study, 161 went on to surgery, and 130 had AA at operation. Four independent correlates of AA were identified and used for the derivation of the following integer‐based scoring system: number of points = 6 for US demonstrating AA + 4 for tenderness in the right lower quadrant + 3 for rebound tenderness + 2 for leukocyte count >12,000/μl. In the external study (201 subjects, 105 males, mean age 28.7 ± 11.9 years, 109 operated, 87 with AA), when the cut‐off of ≥ 8 points for AA was used, sensitivity, specificity, accuracy, and area under the curve of the proposed score were 95.4%, 97.4%, 96.5%, and 93%, respectively, exceeding noticeably the previous models. The proposed scoring system introduces a quantitative combination of the clinical evaluation with US imaging and a marker of inflammatory response, which may enhance the diagnostic accuracy for subjects with suspected AA especially in geographical areas where CT scanning is not readily available on a 24‐hour basis.
Management of Acetabular Fractures in the Elderly Patient
Authors: Cornell Charles N.
Published: August 2005

Operative management of displaced acetabular fractures yields better results than nonoperative management. Over the past decade, surgical approaches to the acetabulum and the surgical tactic for repair of common fracture patterns have been advanced. Excellent outcomes after repair of these injuries can be achieved. In some cases, as in the elderly, or in those cases in which there is significant destruction of the articular cartilage, primary total hip arthroplasty may provide the best solution. Removal of the femoral head allows for excellent exposure of the acetabulum, making it possible to stabilize most fractures without the need for extensile or intrapelvic approaches. The surgical technique that has been successfully used calls for gaining primary stability of the acetabular columns by open reduction and internal fixation and then using the acetabular component to replace the articular surface. The columns need not be anatomically reduced. Multiholed acetabular shells can be used as internal fixation devices by placing screws into the columns enhancing the stability of the repair. In older individuals with severe osteoporosis, a typical fracture pattern results in intrapelvic dislocation of the femoral head with a blowout fracture of the anterior column and medial wall. Reinforcement rings with cemented acetabular fixation can be used in these cases. The femoral head can be used as bulk bone graft to replace and reinforce the reconstruction. Techniques common to revision of failed acetabular components are helpful in this setting. The results of reconstruction of severe acetabular fractures with total hip replacement have been reported to be similar to those achieved for reconstruction of osteoarthritis.
Hip Arthroscopy Update
Authors: Kelly Bryan T. , Buly Robert L.
Published: August 2005

The management of hip injuries in the athlete has evolved significantly in the past few years with theadvancement of arthroscopic techniques. The application of minimally invasive surgical techniques has facilitated relatively rapid returns to sporting activity in recreational and elite athletes alike. Recent advancements in both hip arthroscopy and magnetic resonance imaging have elucidated several sources of intraarticular pathology that result in chronic and disabling hip symptoms. Many of these conditions were previously unrecognized and thus, left untreated. Current indications for hip arthroscopy include management of labral tears, osteoplasty for femoroacetabular impingement, thermal capsulorrhaphy and capsular plication for subtle rotational instability and capsular laxity, lateral impact injury and chondral lesions, osteochondritis dissecans, ligamentum teres injuries, internal and external snapping hip, removal of loose bodies, synovial biopsy, subtotal synovectomy, synovial chondromatosis, infection, and certain cases of mild to moderate osteoarthritis with associated mechanical symptoms. In addition, patients with long-standing, unresolved hip joint pain and positive physical findings may benefit from arthroscopic evaluation. Patients with reproducible symptoms and physical findings that reveal limited functioning, and who have failed an adequate trial of conservative treatment will have the greatest likelihood of success after surgical intervention. Strict attention to thorough diagnostic examination, detailed imaging, and adherence to safe and reproducible surgical techniques, as described in this review, are essential for the success of this procedure.
Justice and Health Care in the Rheumatic Diseases
Authors: MacKenzie C. Ronald , Miller Franklin G. , Fins Joseph J.
Published: August 2005

Coping with a chronic disease is a formidable challenge. Owing to the disabling consequences of their underlying conditions, individuals who suffer with a chronic rheumatic disease have especially daunting lives with their existence often dominated by their health-related needs. Due to the high prevalence, the demographic distribution, indeed the very nature of the rheumatic diseases, too many sufferers of these conditions in our society remain disenfranchised with respect to their access to health care. Those who come from already disadvantaged socioeconomic circumstances face particularly difficult challenges. Rheumatologists and their allied health professionals, therefore, have a moral obligation to ensure greater fairness to their patients—those already compromised by the natural lottery that gave them their disease. To enhance the appreciation of this problem and to motivate the rheumatic disease community, we attempt to identify those variables that create the need for and imperil access to medical care for the rheumatic diseases. The implications of these observations are then explored from the ethical perspective of justice. We conclude with suggestions as to how to change the health care system to address these problems.
The Clinical Use of Allografts, Demineralized Bone Matrices, Synthetic Bone Graft Substitutes and Osteoinductive Growth Factors: A Survey Study
Authors: Bostrom Mathias P. G. , Seigerman Daniel A.
Published: August 2005

The emergence of new bone grafting options and alternatives has led to significant uncertainty when determining the most appropriate product for surgical procedures requiring bone graft in orthopedics. Allografts, demineralized bone matrices, synthetic bone graft substitutes, and osteoinductive growth factors are all viable options, yet there is a lack of data reporting clinical usage of these products. This correspondence reports on the use of bone grafting products at the Hospital for Special Surgery for a 27-month period and makes recommendations based on surgical usage, safety, and cost. Approximately half (48.6%) of all bone graft substitutes were implanted during spinal surgery. Arthroplasty, trauma, and foot/hand cases all used considerable amounts of bone grafting products as well (20.1%, 19.0%, 12.1%, respectively). Considerable differences were noticed in usage of bone grafting products among each orthopedic discipline. Of all bone graft substitutes used in arthroplasty, 14.4% were demineralized bone matrices, whereas 56.8% were allografts. Demineralized bone matrix grafts were used in 82% of trauma surgery and 89% of foot/hand cases. An increase in synthetic bone graft alternatives was noticed near the end of our investigation period.
Posttraumatic Reconstruction of the Ankle Using the Ilizarov Method
Authors: Rozbruch S. Robert
Published: August 2005

Reconstruction of the ankle after trauma requires a variety of treatment strategies. Once the personality of the problem is appreciated, a tailored approach may be implemented. The Ilizarov method provides a versatile, powerful, and safe approach. It is particularly useful in the setting of infection, bone loss, poor soft tissue envelope, leg length discrepancy, bony deformity, and joint contracture. In this article, a variety of posttraumatic ankle pathologies are discussed. Treatment methods including osteotomy, arthrodesis, distraction, correction of contracture, nonunion repair, and tibia and fibula lengthening are reviewed. The use of the Ilizarov method for acute and/or gradual correction as well as the application of simultaneous treatments at multiple levels is discussed in this article.
The Delay in Diagnosis of Slipped Capital Femoral Epiphysis: A Review of 102 Patients
Authors: Green Daniel W. , Reynolds Richard A. K. , Khan Safdar N. , Tolo Vernon
Published: August 2005

Objectives

The aim of this study were (1) to evaluate the incidence of apparent missed diagnosis of slipped capital femoral epiphysis (SCFE) by the primary care system and (2) to identify possible factors leading to a delay in diagnosis of this disorder.

Setting and Design

A retrospective review of emergency department records, outside medical charts, and preoperative and postoperative radiographs of children treated surgically for SCFE at the Children's Hospital of Los Angeles (CHLA) from 1989 to 1997 was done to assess the delay in diagnosis for SCFE. The primary care system included outside emergency department visits, urgent care clinic visits, and private office visits.

Results

Of 102 patients (69 men, 33 women; mean age at surgery, 11.9 years), 68% were above the 95th percentile mean weight for age. Pain in the hip and/or groin was documented in 60%. The mean duration of symptoms experienced before being seen at CHLA was 140 days (hours to 1.5 years) and the mean delay after the first primary care visit till being seen at CHLA was 76 days (hours to 1 year). Fifty-two percent of primary care visits for hip, groin, knee, or thigh pain in obese children did not lead to either a diagnosis of SCFE or a referral for orthopedic evaluation.

Conclusions

This study documents a 2 1/2-month delay and a 52% incidence of apparent missed diagnosis for SCFE by the primary care system. There seems to be a need for increased orthopedic education for primary care providers.
Bone Morphogenic Proteins: Applications in Spinal Surgery
Authors: Jeong Gerard K. , Sandhu Harvinder S. , Farmer James
Published: August 2005

The prospect of predictable and reliable oseteogenesis without the need for secondary bone grafting to treat a wide spectrum of spinal disorders is tremendously appealing. Recombinant human bone morphogenic proteins (rhBMP) have been the subject of extensive basic science, animal, and clinical research as a potential therapeutic modality to promote bony fusion. Animal studies and prospective, randomized clinical trials have demonstrated the efficacy of rhBMPs as an adjunct or substitute to autogenous bone graft in the specific treatment of certain spinal conditions. The future role of rhBMPs in spinal surgery applications remains to be determined and will be dependent upon future investigations evaluating 1) the efficacy in a variety of spinal conditions and environments, 2) the optimal dose and delivery system, 3) the long-term safety profile (immunogenicity, antibody formation), and 4) the cost effectiveness of these therapeutic growth factors.
The Use of Reinfusion Drains after Total Knee Arthroplasty in Patients Treated with Low Molecular Weight Heparin for Thromboembolic Prophylaxis
Authors: Gordon Alexander C. , Pulido Pam , Copp Steven N. , Ezzet Kace A. , Walker Richard H. , Colwell Clifford W.
Published: August 2005

The effect of closed-suction drainage with red-cell reinfusion on patients receiving low molecular weight heparin (LMWH) prophylaxis after total knee arthroplasty (TKA) has not been previously studied. Therefore, our goals were to determine the effect of reinfusion drains and LMWH on allogeneic transfusions and wound complications after TKA by comparing patients treated with and without drains. Overall, transfusion rates were lower in the drain group (40% vs 15%, P=.04). Patients with reinfusion drains had a significantly higher rate of allogeneic transfusion (15.8%) than those predonating autologous blood and no drain (5.4%, P=.0003). The drain group had lower rates of wound complications ( P=not significant). We were unable to demonstrate the efficacy of red-cell reinfusion as a substitute for autologous donation in TKA.
Large sample behaviors of the generalized likelihood uncertainty estimation (GLUE) in assessing the uncertainty of rainfall‐runoff simulations
Authors: Montanari Alberto
Published: August 2005

Several methods have been recently proposed for quantifying the uncertainty of hydrological models. These techniques are based upon different hypotheses, are diverse in nature, and produce outputs that can significantly differ in some cases. One of the favored methods for uncertainty assessment in rainfall‐runoff modeling is the generalized likelihood uncertainty estimation (GLUE). However, some fundamental questions related to its application remain unresolved. One such question is that GLUE relies on some explicit and implicit assumptions, and it is not fully clear how these may affect the uncertainty estimation when referring to large samples of data. The purpose of this study is to address this issue by assessing how GLUE performs in detecting uncertainty in the simulation of long series of synthetic river flows. The study aims to (1) discuss the hypotheses underlying GLUE and derive indications about their effects on the uncertainty estimation, and (2) compare the GLUE prediction limits with a large sample of data that is to be simulated in the presence of known sources of uncertainty. The analysis shows that the prediction limits provided by GLUE do not necessarily include a percentage close to their confidence level of the observed data. In fact, in all the experiments, GLUE underestimates the total uncertainty of the simulation provided by the hydrological model.
Using a multi‐dimensional satellite rainfall error model to characterize uncertainty in soil moisture fields simulated by an offline land surface model
Authors: Hossain Faisal , Anagnostou Emmanouil N.
Published: August 2005

In this study, we investigate the significance of using an improved error modeling strategy to characterize the spatio‐temporal characteristics of uncertainty in simulation of soil moisture fields from an off‐line land surface model forced with satellite rainfall data. We coupled a Two‐Dimensional Satellite Rainfall Error Model (SREM2D) with the Common Land Model to propagate ensembles of simulated satellite rain fields for the prediction of soil moisture at depths of 5 cm (near surface) and 50 cm (root zone). Our investigations revealed that multi‐dimensional error modeling captures the spatio‐temporal characteristics of soil moisture uncertainty with higher consistency than simpler bi‐dimensional error modeling strategies. The proposed error modeling strategy appears to have the potential for delineating a more robust framework for the optimal integration of satellite rainfall data into models towards the study of global water and energy cycle.
Seismic monitoring of the Indian Ocean tsunami
Authors: Yuan Xiaohui , Kind Rainer , Pedersen Helle A.
Published: August 2005

The 26 December 2004 Sumatra‐Andaman earthquake of Mw 9.3 triggered a massive tsunami in the Indian Ocean. We here report on observations of the Indian Ocean tsunami at broadband seismic stations located on islands in the area. The tsunami induces long‐period (>1000 s) signals on the horizontal components of the sensor. Frequency‐time analysis shows that the long‐period signals cannot be due to seismic surface waves, but that it arrives at the expected time of the tsunami. The waveforms are well correlated to tide gauge observations at a location where both observations are available. To explain the signals we favour tilt due to coastal loading but we cannot at the present stage exclude gravitational effects. The density of broadband stations is expected to increase rapidly in the effort of building an earthquake monitoring system. They may unexpectedly become useful tsunami detectors as well.
Observation operators for the direct assimilation of TRMM microwave imager retrieved soil moisture
Authors: Drusch M. , Wood E. F. , Gao H.
Published: August 2005

Each soil moisture data set is characterized by its specific mean value, variability, and dynamical range. For the assimilation of soil moisture observations into numerical models observation operators have to be developed, which reduce systematic differences. In this study, cumulative distribution function (CDF) matching is used to derive observation operators for TRMM Microwave Imager (TMI) derived soil moisture for the southern US, modeled soil moisture fields from the European Centre for Medium‐Range Weather Forecasts (ECMWF), and model output from the Variable Infiltration Capacity model (VIC). It is found that the transferability of these observation operators in space and time strongly depends on the geographical region. In the Central US, where the assimilation of soil moisture is most promising, the observation operator exhibits little variability in time. The temporal variability in the observation operator can result in substantial differences between the modeled field and the observation. In Numerical Weather Prediction (NWP) applications, where the model tends to be updated on a regular basis, dynamic observation operators will be necessary to assimilate soil moisture. For climate studies or re‐analysis projects long time series are required to define an observation operator, which correctly reproduces interannual variability.
Mechanisms of xenon‐ and isoflurane‐induced preconditioning – a potential link to the cytoskeleton via the MAPKAPK‐2/HSP27 pathway
Authors: Weber Nina C , Toma Octavian , Wolter Jessica I , Wirthle Nicole M , Schlack Wolfgang , Preckel Benedikt
Published: August 2005

We previously demonstrated that the anesthetic gas xenon exerts cardioprotection by preconditioning in vivo via activation of protein kinase C (PKC)‐ɛ and p38 mitogen‐activated protein kinase (MAPK). P38 MAPK interacts with the actin cytoskeleton via the MAPK‐activated protein kinase‐2 (MAPKAPK‐2) and heat‐shock protein 27 (HSP27). The present study further elucidated the underlying molecular mechanism of xenon‐induced preconditioning (Xe‐PC) by focusing on a potential link of xenon to the cytoskeleton.

Anesthetized rats received either xenon (Xe‐PC, n=6) or the volatile anesthetic isoflurane (Iso‐PC, n=6) during three 5‐min periods interspersed with two 5‐min and one final 10‐min washout period. Control rats (n=6) remained untreated for 45 min. Additional rats were either pretreated with the PKC inhibitor Calphostin C (0.1 mg kg−1) or with the p38 MAPK inhibitor SB203580 (1 mg kg−1) with and without anesthetic preconditioning (each, n=6). Hearts were excised for immunohistochemistry of F‐actin fibers and phosphorylated HSP27. Phosphorylation of MAPKAPK‐2 and HSP27 were assessed by Western blot. HSP27 and actin colocalization were investigated by co‐immunoprecipitation.

Xe‐PC induced phosphorylation of MAPKAPK‐2 (control 1.0±0.2 vs Xe‐PC 1.6±0.1, P<0.05) and HSP27 (control 5.0±0.5 vs Xe‐PC 9.8±1.0, P<0.001). Both effects were blocked by Calphostin C and SB203580. Xe‐PC enhanced translocation of HSP27 to the particulate fraction and increased F‐actin polymerization. F‐actin and pHSP27 were colocalized after Xe‐PC.

Xe‐PC activates MAPKAPK‐2 and HSP27 downstream of PKC and p38 MAPK. These data link Xe‐PC to the cytoskeleton, revealing new insights into the mechanisms of Xe‐PC in vivo.

British Journal of Pharmacology (2005) 146, 445–455. doi:10.1038/sj.bjp.0706324
Neuroprotective effect of paeoniflorin on cerebral ischemic rat by activating adenosine A1 receptor in a manner different from its classical agonists
Authors: Liu Da‐Zhi , Xie Ke‐Qiang , Ji Xin‐Quan , Ye Yang , Jiang Cheng‐Liang , Zhu Xing‐Zu
Published: August 2005

The effects of paeoniflorin (PF), a compound isolated from Paeony radix, on neurological impairment and histologically measured infarction volume following transient and permanent focal ischemia were examined in Sprague–Dawley rats.

In transient ischemia model, rats were subjected to a 1.5‐h occlusion of the middle cerebral artery (MCA). The administration of PF (2.5 and 5 mg kg−1, s.c.) produced a dose‐dependent decrease in both neurological impairment and the histologically measured infarction volume. Similar results were also obtained when PF (2.5, 5, and 10 mg kg−1, s.c.) was given in permanent ischemia model.

The neuroprotective effect of PF (10 mg kg−1, s.c.) was abolished by pretreatment of DPCPX (0.25 mg kg−1, s.c.), a selective adenosine A1 receptor (A1R) antagonist.

PF (10, 40, and 160 mg kg−1, i.v.) had no effect on mean arterial pressure (MAP) and heart rates (HR) in the conscious rat. Additionally, PF (10−3 mol l−1) had no effect on noradrenaline‐ (NA‐) or high K+ concentration‐induced contractions of isolated rabbit primary artery.

In competitive binding experiments, PF did not compete with the binding of [3H]DPCPX, but displaced the binding of [3H]NECA to the membrane preparation of rat cerebral cortex. This binding manner was distinguished from the classical A1R agonists.

The results demonstrated that activation of A1R might be involved in PF‐induced neuroprotection in cerebral ischemia in rat. However, PF had no ‘well‐known’ cardiovascular side effects of classical A1R agonists. The results suggest that PF might have the potential therapeutic value as an anti‐stroke drug.

British Journal of Pharmacology (2005) 146, 604–611. doi:10.1038/sj.bjp.0706335
Intracellular pathways triggered by the selective FLT‐1‐agonist placental growth factor in vascular smooth muscle cells exposed to hypoxia
Authors: Bellik Lydia , Vinci Maria Cristina , Filippi Sandra , Ledda Fabrizio , Parenti Astrid
Published: August 2005

We have previously shown that hypoxia makes vascular smooth muscle cells (VSMCs) responsive to placental growth factor (P1GF) through the induction of functional fms‐like tyrosine kinase (Flt‐1) receptors. The aim of this study was to investigate the molecular mechanisms involved in the P1GF effects on proliferation and contraction of VSMCs previously exposed to hypoxia (3% O2).

In cultured rat VSMCs exposed to hypoxia, P1GF increased the phosphorylation of protein kinase B (Akt), p38 and STAT3; activation of STAT3 was higher than that of other kinases. In agreement with this finding, the proliferation of hypoxia‐treated VSMCs in response to P1GF was significantly impaired by the p38 and the phosphatidylinositol 3‐kinase inhibitors SB202190 and LY294002, respectively, and was almost completely prevented by AG490, a janus tyrosine kinase (JAK)/signal transducer and activator of transcription (STAT) inhibitor.

Since hypoxia was able to reverse the vasorelaxant effect of P1GF into a vasoconstrictor response, the mechanism of this latter effect was also investigated. Significant Flt‐1 activity was measured in isolated preparations from rat aorta exposed to hypoxia. Inhibitors of mitogen‐activated protein kinase kinase, Akt and STAT3 induced a modest inhibition of the vasoconstrictor response to P1GF, while the p38 inhibitor SB202190 markedly impaired the P1GF‐induced contractile response. These effects were selectively mediated by Flt‐1 without any involvement of foetal liver kinase‐1 receptors.

These data are the first evidence that different intracellular pathways activated by Flt‐1 receptor in VSMCs are involved in diverse biological effects of P1GF: while mitogen activated protein kinase kinase/extracellular signal regulated kinase1/2 and JAK/STAT play a role in VSMC proliferation, p38 is involved in VSMC contraction. These findings may highlight the role of P1GF in vascular pathology.

British Journal of Pharmacology (2005) 146, 568–575. doi:10.1038/sj.bjp.0706347