bluuebunny/crossref_metadata_2025 huggingface dataset:
Intramolecular excimer formation in macromolecules. II. Energy migration and excimer formation in acenaphthylene‐methyl methacrylate copolymers
Authors: Reid R. F. , Soutar I.
Published: August 2005

Excimer formation has been studied in a series of ancenaphthylene—methyl methacrylate copolymers of content varying over the total composition range. In accord with a previous model [Reid and Soutar, J. Polym. Sci. Polym. Lett. Ed., 15, 153 (1977)], the excimer formation has been described by a composite function representative of energy migration and excimer site concentration. In tramolecular energy migration in glassy solutions of the polymers was characterized by use of fluorescence depolarization measurements. The extent of energy migration in the acenaphthylene copolymers is determined by the mole fraction of aromatic chromophore fa. A function Σ descriptive of the excimer site concentration has been generated on the assumption that excimer formation results predominantly from next‐ to nearest‐neighbor interactions. Σ is based upon the pentad distribution of aromatic chromophores in the chain and contains pentad fractions appropriately weighted according to the frequency and relative importance of their potential excimer sites. Reactivity ratios of acenaphthylene and methyl methacrylate in copolymerization at 70°C were ra = 0.80 and rm = 0.57.
Proton spin‐relaxation study of the polymerization of diacetylene in a single crystal
Authors: Höptner W. , Von Schütz J. U. , Wolf H. C.
Published: August 2005

Proton spin‐lattice relaxation experiments on the bis‐(p‐toluenesulfonate) of 2,4‐hexadiyne‐1,6‐diol (TSHD) as a function of temperature (25 to 353 K), of frequency (22 and 44 MHz), and of conversion to polymer were performed to determine the molecular motions in this crystal and to follow the conversion via the changes in the relaxation time T1. It was found that T1 is dominated below 125 K by weakly hindered (ΔE = 2.8 kJ/mole) tunneling (Λ = 220 MHz) CH3 groups, at about 160 K by order‐disorder fluctuations around the phase‐transition temperature ϑc which depends strongly on the conversion, and above 200 K by the motion of the whole side group. T1 can be used as sensitive probe for the conversion: The change in T1 at about 44 K is directly proportional to the conversion, whereas the change at high temperatures (e.g., 353 K) occurs essentially at low conversions (⩽10%). This is explained by distorted (stressed) areas around the isolated polymer chains, which are estimated to be about 16 times the size of the chains. After an induction period the stresses are relieved by further polymerization.
Thermoelasticity of networks in swelling equilibrium with mixed diluents: Specific polymer‐diluent interactions
Authors: Britton A. T. , Sullivan J. L. , Smith K. J.
Published: August 2005

Thermoelasticity studies of poly(vinyl alcohol) networks swollen in aqueous glycol indicate that the effects of specific polymer‐diluent interactions diminish at high swelling, much as in the situation of poly(vinyl alcohol) in pure water reported earlier. In 20% glycol, the ratio of the energy component fe of the force to the total force f was found to be −0.59 at high swelling. Swelling was controlled by the degree of network crosslinking. Evidence that fe/f could be determined under the condition of a null thermal expansion coefficient was not obtained; in fact, the contrary was indicated.
Triple helix of a schizophyllum commune polysaccharide in aqueous solution
Authors: Norisuye Takashi , Yanaki Toshio , Fujita Hiroshi
Published: August 2005

From sedimentation equilibrium, light scattering, and viscosity measurements on a series of native and sonicated samples of schizophyllan, and extracellular β‐1,3‐D‐glucan, the following results were obtained: (i) weight‐average and z‐average molecular weights (M̄w and M̄z) in water are about three times as large as those in dimethylsulfoxide (DMSO); (ii) the exponent in the Houwink‐Mark‐Sakurada intrinsic viscosity relation in water is close to 1.7, whereas in DMSO it is 0.68; (iii) intrinsic viscosities of samples with M̄w below 5 × 105 in water at 25°C can be fitted by Yamakawa's theory for along rigid rod if the pitch (1.836 nm) of the triple helix of Atkins et al. and the diameter (3 nm) estimated from the model triple helix are used; (iv) intrinsic viscosities in water‐DMSO mixtures at 25°C undergo and almost discontinuous decrease when the weight fraction of DMSO in the mixture increases to about 87%. These results combined lead to the conclusion that schizophyllan dissolves in water as a triple helix similar to that proposed by Atkins et al. and that the triple helix in aqueous DMSO solution “melts” abruptly to single chains when the DMSO coposition reaches about 87 wt%. It was also found that the triple helix is not recoverable once it is broken in DMSO.
Solid‐State coextrusion of high‐density polyethylene. II. Effect of molecular weight and molecular weight distribution
Authors: Zachariades Anagnostis E. , Kanamoto Tetsuo , Porter Roger S.
Published: August 2005

The recently developed technique of solid‐state coextrusion for ultradrawing semicrystalline thermoplastics has been applied in the preparation of self‐reinforced high‐density polyethylene extrudates. The extrudates consist of definite core and sheath phases composed of different molecular weights (Mw) in the range of 60,000–250,000 and different molecular weight distributions (Mw/Mn = 3.0–20). Concentric billets of two different phases were prepared for extrusion by in serting a polyethylene rod within a tubular billet of a different high‐density polyethylene followed by melting the two phases to obtain bonding between them. The billet was then split longitudinally to increase extrusion speed and extruded at 120°C, 0.23 GPa through a conical die of extrusion draw ratio 25. Extrudates of high tensile modulus (38 GPa) and strength (0.50 GPa) could be produced in a steady state process at a rate near 0.25 cm/min. The tensile properties of the extrudates from either the single or concentric billets increased with average molecular weight and were insensitive to the molecular weight distribution of the constituent phases. Thermal analysis indicated a high deformation efficiency for the sheath and core phases of the extrudates by the coextrusion technique.
Fourier transform infrared investigation of the effects of irradiation on the 19 and 30°C phase transitions in polytetrafluoroethylene
Authors: Vanni H. , Rabolt J. F.
Published: August 2005

Fourier transform infrared spectroscopy has been used in conjunction with differential scanning calorimetric measurements to investigate the nature of molecular degradation and its effect on the phase transition temperatures in irradiated polytetrafluoroethylene (PTFE). Both the 19 and 30°C transitions are observed to exhibit similar shifts to low temperatures upon irradiation. Infrared absorbance subtraction data from irradiated PTFE indicate a continual decrease in sample crystallinity accompanied by an increase in the number of free and bonded COOH groups with increasing dose consistent with molecular degradation by chain scission. By comparing infrared band intensities on a number of irradiated PTFE samples with those from short chain perfluoro n‐alkanes, it was determined that the overall reduction in chain length caused by irradiation was primarily responsible for the observed reduction in both phase transition temperatures.
Influence of chain conformation on translational diffusion of poly(2‐vinyl pyridine) in dilute solution
Authors: Chao D. Y. , Jamieson A. M.
Published: August 2005

A comparative photon correlation spectroscopy study is reported of the concentration‐dependent translational diffusion coefficient Dt of atactic poly(2‐vinyl pyridine) in tetrahydrofuran and in aqueous solution, in the form of the poly(2‐vinyl pyridinium)chloride salt (α = 0.4). The limiting Stokes radius of the polymer is observed to be identical within experimental error in tetrahydrofuran (THF) at temperatures below 30°C and in aqueous solutions at high ionic strength. This numerical value is comparable to expectation for an unperturbed atactic vinyl polymer chain and indicates a compact, possibly micellar, conformation. Raising the temperature in THF above 30°C and decreasing the ionic strength or increasing the ionization above α = 0.4 in aqueous solvents causes a discontinuous cooperative transition to a more expanded structure. The effect of the conformational change is also manifest in the concentration dependence of Dt. Using experimental estimates of the second osmotic virial coefficients obtained by total scattered intensity measurements, the experimental data for dDt/dc are compared with prediction based on hydrodynamic theory. Substantial disagreement is found between theory and experiment, especially in the aqueous system. In 0.01M NaCl, decrease in polyion concentration induces the transition from the compact form to a highly extended structure. Angle‐dependent quasielastic light scattering data from the expanded state provides information about the intramolecular chain dynamics.
Effects of spinning conditions on the mechanical properties of ultrahigh‐molecular‐weight polyethylene fibers
Authors: Ohta Yasuo , Murase Hiroki , Hashimoto Takeji
Published: August 2005

We investigated the tensile strength and modulus of ultrahigh‐strength polyethylene (UHSPE) fibers obtained by using the special two‐step‐drawing process of as‐spun fiber (ASFs) which were prepared by the so‐called gel‐spinning method. We have found that the higher the ASF's spinning speed is, the higher the attainable tensile strength σf and modulus E are. For all the fibers drawn from ASFs with various spinning speed except for 120 m/min, we have found a master curve for the inverse of σf which is plotted as a function of T1/4E−1/2, where T is the linear density of the drawn fibers, in consistent with the Griffith theory: a thicker fiber obtained with a lower spinning speed exhibits lower strength, although all the AFSs possess the same value of E. This also suggests that a thicker fiber contains more defects which would lead to the Griffith‐type crack propagation breakage. Moreover, from morphological observation of ASFs under transmission electron microscopy, the ASF obtained at a relatively low spinning speed possesses a heterogeneous cross‐sectional morphology, whereas that obtained at relatively high spinning speed possesses a relatively homogenous morphology. We propose that this morphological evidence may account for the experimental findings of the behavior of the mechanical properties described above. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2639–2652, 2005
Gas permeability and selectivity of hexafluoroisopropylidene aromatic isophthalic copolyamides
Authors: Carrera‐Figueiras Cristian , Aguilar‐Vega Manuel
Published: August 2005

The synthesis, thermal, and gas transport properties of poly(hexafluoroisopropylidene isophthalamide), HFA/ISO homopolymer, and HFA/TERT‐co‐HFA/ISO copolyamides with different poly(hexafluoroisopropilydene‐5‐t‐butylisophthalamide), HFA/TERT, ratios are reported. The results indicate that the glass transition temperatures of the copolyamides increase as the concentration of HFA/TERT in the polyamide increases. The gas permeability coefficients in the polyamides and copolyamides are independent of pressure or decrease slightly particularly with CO2, N2, and CH4. It was seen that HFA/TERT is 2–6 times more permeable than HFA/ISO, depending on the gas being considered. This was assigned to the presence of the bulky lateral substituent, t‐butyl group in HFA/TERT and HFA/TERT‐co‐HFA/ISO copolyamides. This substituent increases fractional free‐volume, as expected. Therefore, the gas permeability and diffusion coefficients generally increase with increasing fractional free‐volume. The experimental results for the gas permeability and permselectivity for the copolyamides was well represented by a logarithmic mixing rule of the homopolyamides permeability coefficients and their volume fraction. The selectivity of gas pairs, such as O2/N2, CO2/CH4, and N2/CH4 decreased slightly with the addition of HFA/TERT. The temperature dependence of permeability for homopolyamides and copolyamides can be described by an Arrhenius type equation. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2625–2638, 2005
Experimental study of a pulsed microwave plasma assisted chemical vapour deposition of carbon nanotubes
Authors: Belmahi M. , Le Brizoual L. , Assouar M. B. , Tousch T. , Vergnat M. , Bougdira J. , Alnot P.
Published: August 2005

In this study we present the first results achieved on the growth of carbon nanotubes (CNT) in both continuous mode (CM) and pulsed mode (PM) microwave plasma assisted chemical vapour deposition (MPACVD). The interest of this work is to determine the influence of the discharge parameters on the CNT properties such as diameter, length, density … etc. The experiments were carried out at a sustrate temperature around 900 °C. The catalyst used was nanostructured Fe–SiO deposited on silicide. It was found that the formation of multiwalls carbone nanotubes (MWCNTs) occurs when varying the discharge parameter from the CM to the PM and a selective growth of bundles of MWCNTs is obtained in the optimal PM plasma mode conditions. The measured diameter of isolated MWCNTs in the CM is around 20 nm. We measured a decrease of the amorphous carbon structures by a factor 7 and an increase of the CNT density by a factor 3 from the CM to the PM, confirming that the pulsed mode is more suitable for the MWCNT growth. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
TL, OSL, Raman spectroscopy and SEM characterization of boron doped diamond films
Authors: Pedroza‐Montero M. , Chernov V. , Castañeda B. , Meléndrez R. , Gonçalves J. A. N. , Sandonato G. M. , Bernal R. , Cruz‐Vázquez C. , Brown F. , Cruz‐Zaragoza E. , Barboza‐Flores M.
Published: August 2005

Hot filament chemically vapor deposited (HFCVD) boron doped diamond films were grown on monocrystalline silicon (111) doped with B/C ratios of 4000, 8000 and 12,000 ppm. Scanning electron micrographs show that the films are composed of well‐faceted microcrystallites ranging in size from about 1 to 5 µm with no correlation with B/C concentration. The Raman spectra exhibit a sharp dia‐ mond band at 1332 cm–1 which shifts to lower wave numbers, broaden and decreases as the B/C ratio increases. An additional broad band is observed around 1200 cm–1. The beta irradiated diamond films exhibit thermoluminescence (TL) and optically stimulated luminescence (OSL) and the TL glow curves can be fitted well with four glow peaks. The kinetic parameters of these TL peaks as well as their intensities depend on B/C ratio. The OSL curves of the diamond films grown with 4000 and 8000 ppm of B/C exhibit standard decay behaviour for continuos stimulation with light of 470 nm. However, the OSL signal of the 12,000 ppm film increases initially with light stimulation, reaching a maximum to decay afterwards. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improvement of the electrical properties of compensated phosphorus‐doped diamond by high temperature annealing
Authors: Chevallier J. , Saguy C. , Barbé M. , Jomard F. , Ballutaud D. , Kociniewski T. , Philosoph B. , Fizgeer B. , Koizumi S.
Published: August 2005

We have followed the evolution of the electrical and infrared absorption properties of two phosphorus‐doped epitaxial layers under a series of isochronal annealings between 800 °C and 1400 °C. In the as‐grown state, one sample is weakly compensated (Na/Nd= 0.15) while the other one is highly compensated (Na/Nd = 0.73). Under thermal annealing, both the electrical and infrared properties of the weakly compensated remain unchanged. On the contrary, the highly compensated sample becomes weakly compensated (Na/Nd = 0.15) after annealing at 1000 °C, 30 min while the neutral phosphorus concentration remains constant. This result is explained in terms of a migration of negatively charged acceptors followed by trapping on P+ donors. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Toward information sharing support by agents: An experiment to unveil effects of support on information‐providing activities
Authors: Hayashida Naoko , Yamaki Hirofumi , Kida Koji , Yamaguchi Tomoharu
Published: August 2005

It is not easy for anyone to obtain up‐to‐date information that meets one's needs on the street, since such information is usually fragmentary and volatile. Such environments in real cities are different from “global” network environments, like the conventional World Wide Web. Users can put information they want to share with others in any accessible location in the global networks. However, it is not possible in the environments in cities. Thus, it is necessary to provide a framework that promotes more active information sharing for the environments in cities. To realize such a framework, we propose an agent which supports information sharing by reducing risks for providing information. This study focuses on promoting the provision of information. We studied the effect of “risk elements,” which can be interpreted as negative considerations (or anxiety) of information providers. We report the results of an experiment, performed to clarify some elements that influence information‐providing acts in cities. This experiment has shown that supports which reduce the risk factor can promote information‐providing activities even if no other incentive such as money as a reward or reduction of costs is provided. It was also shown that multiple supports are not always more effective than a single support although each support is effective by itself. In this paper, we discuss an agent function to promote information‐providing activities, based on the results of the experiment and questionnaires. © 2005 Wiley Periodicals, Inc. Syst Comp Jpn, 36(11): 93–101, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ scj.10658
Local computation of optical flow using a silicon retina
Authors: Akiyama Kei , Luo Zhi‐Wei , Onishi Masaki , Yagi Tetsuya , Hosoe Shigeyuki
Published: August 2005

Chiefly for applications to robots that operate in a real environment, it is desirable to construct a compact vision system with real‐time properties and adaptability to the environment. The silicon retina is an image sensor considered from such a viewpoint, in which the preprocessing mechanism in the biological retina is simulated in an analog CMOS integrated circuit. This paper proposes a computation scheme which estimates the optical flow (the moving velocity field of an object that is in relative motion with respect to the imaging system) robustly even in images of a real environment, focusing on the function and structure of the silicon retina. In the proposed method, the edge of the moving object is extracted from the response image on the silicon retina. By applying local computation to the result, the optical flow can be derived efficiently even in a real environment. An experiment is performed using the silicon retina and a computer based on the proposed method, and satisfactory results are obtained. © 2005 Wiley Periodicals, Inc. Syst Comp Jpn, 36(11): 12–23, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20343
A high‐efficiency method to replace essential genes with mutant alleles in yeast
Authors: Widlund Per O. , Davis Trisha N.
Published: August 2005

Temperature‐sensitive (TS), internally deleted and truncated alleles are important tools to facilitate the characterization of essential genes. We have developed a straightforward method to replace a wild‐type gene with a mutant allele at the endogenous locus. This method is an efficient alternative to the two‐step method for integration of alleles that are compromised in function or contain multiple mutations. A strain is constructed that has the essential gene of interest disrupted by a selectable marker. Strain viability is maintained by a plasmid carrying a copy of the essential wild‐type gene and the ADE3 gene. The mutant allele is cloned into an integratable vector carrying a selectable/counter‐selectable marker, such as URA3. The plasmid is linearized and transformed, directing integration to the 5′ or 3′ region flanking the essential open reading frame (ORF). Transformants that have integrated the mutant gene at the endogenous locus can lose the autonomous plasmid carrying the wild‐type copy of the essential gene and the ADE3 gene. These transformants are identifiable as white sectoring colonies, display the mutant phenotype and may be characterized. An optional second selection step on 5‐fluoroorotic acid (5‐FOA) selects for popouts of the integrating vector sequences, leaves the mutant allele at the endogenous locus, and recycles selectable markers. We have used this method to integrate a TS allele of SPC110 that could not be integrated by standard methods. Copyright © 2005 John Wiley & Sons, Ltd.
Cytosine deaminase MX cassettes as positive/negative selectable markers in Saccharomyces cerevisiae
Authors: Hartzog Phillip E. , Nicholson Bradly P. , McCusker John H.
Published: August 2005

We describe positive/negative selectable cytosine deaminase MX cassettes for use in Saccharomyces cerevisiae. The basis of positive selection for cytosine deaminase (Fcy1) activity is that (a) fcy1 strains are unable to grow on medium containing cytosine as a sole nitrogen source and (b) fcy1 ura3 strains are unable to grow on medium containing cytosine as the sole pyrimidine source. Conversely, as 5‐fluorocytosine (5FC) is toxic to cytosine deaminase‐producing cells, fcy1 strains are resistant to 5FC. FCY1MX and FCA1MX cassettes, containing open reading frames (ORFs) of S. cerevisiae FCY1 and Candida albicans FCA1, respectively, were constructed and used to disrupt targeted genes in S. cerevisiae fcy1 strains. In addition, new direct repeat cassettes, kanPR, FCA1PR, FCY1PR and CaURA3PR, were developed to allow efficient deletion of target genes in cells containing MX3 repeats. Finally, the FCY1‐ and FCA1MX3 or PR direct repeat cassettes can be readily recycled after 5FC counter‐selection on both synthetic and rich media. Copyright © 2005 John Wiley & Sons, Ltd.
Hydatid Disease of the Abdomen and Other Locations
Authors: Tsaroucha Alexandra K. , Polychronidis Alexandros C. , Lyrantzopoulos Nikolaos , Pitiakoudis Michail S. , J.Karayiannakis Anastasios , Manolas Konstantinos J. , Simopoulos Constantinos E.
Published: August 2005

We present patients treated for hydatid disease in our hospital (in northeastern Greece) over the last 20 years. In the period from 1984 to 2003, a total of 135 patients (54 male, 81 female) were treated for echinococcal disease (age 15–85 years). In 111 (82.2%) patients only the liver was affected; 9 (6.7%) patients had concomitant hepatic and extrahepatic hydatid disease; and 15 (11.1%) patients had only extrahepatic disease. Clinical symptoms in patients with hepatic locations of the disease included abdominal pain localized in the epigastrium or right upper quadrant of the abdomen, tenderness, hepatomegaly with palpable abdominal mass, jaundice, fever, and anaphylactic reaction. All the patients were treated surgically. Surgical techniques included partial cystectomy and drainage, cystectomy and capitonage, cystectomy and omentoplasty, only drainage, left lateral hepatectomy, total pericystectomy, and laparoscopic pericystectomy. Rupture into the bile duct was managed by T‐tube drainage or biliodigestive anastomosis. Symptoms and surgical treatment for extrahepatic cysts varied according to the location of the cyst. The median cyst diameter of all patients was 11 cm. The postoperative complication rate was 17.0%. Two patients died (1.5%). The median hospital stay was 18 days. The recurrence rate was 6.7%. The study suggests that treatment of this benign disease should be the less radical surgical technique combined with pre‐ and postoperative anthelmintic administration. The surgical treatment should be combined with careful use of scolicidal fluids and aspiration of the cyst to avoid contamination and minimize the risk of recurrence.
Early Follow-up for a Hybrid Total Hip Arthroplasty Using a Metal-Backed Acetabular Component Designed to Reduce “Backside” Polyethylene Wear
Authors: Poole Colin E. , Patil Shantanu S. , D'Lima Darryl D. , Colwell Clifford W.
Published: August 2005

Modular acetabular systems have several advantages; however, increased polyethylene wear has been recognized as a disadvantage. In our study, an acetabular shell design with a highly polished inner surface, a locking mechanism that minimizes micromotion, and a high polyethylene liner to shell conformity was evaluated. A prospective cohort of 50 consecutive hips was followed up for a mean of 3.6 years (range, 2–7 years). One patient required an early revision for recurrent instability. Mean linear head penetration rates were 0.242 mm/year (range, 0.048–0.655 mm/year). The true linear wear rate was calculated after subtracting the linear wear in the first follow-up year from the total wear at the end of the follow-up. The true linear wear rate was 0.173 mm/year (range, 0.03–0.423 mm/year). A positive correlation was found between wear rate and male gender. The low head penetration rates suggest that a polished liner with an improved locking mechanism and increased liner conformity can reduce polyethylene wear.
Escobar Syndrome (Multiple Pterygium Syndrome) Associated with Thoracic Kyphoscoliosis, Lordoscoliosis, and Severe Restrictive Lung Disease: A Case Report
Authors: Dodson Christopher C. , Boachie-Adjei Oheneba
Published: August 2005

Background

Escobar syndrome or multiple pterygium syndrome is characterized by a web across every flexion crease in the extremities, most notably the popliteal space. In addition, this syndrome is associated with two other structural anomalies: a vertical talus and congenital lordoscoliosis. We present a case report of a patient with Escobar syndrome who was initially managed conservatively and subsequently had severe and debilitating progression and respiratory decompensation ultimately requiring surgical intervention.

Study Design

Case report.

Methods

After preoperative evaluation by a pediatrician, pulmonologist, and otolaryngologist, the patient underwent one-stage anterior and posterior spinal fusion with instrumentation as well as multiple osteotomies, rib resections, and vertebrectomies.

Results

The patient's postoperative course was complicated by wound necrosis requiring irrigation and debridement, a urinary tract infection, and a tracheostomy for persistent atelectasis. The patient eventually recovered from all complications. There were never any focal neurologic deficits. The patient had a 3-year follow-up with radiographically confirmed maintenance of correction. Fusion was obtained in the anterior and posterior segments. Clinically, the patient is able to stand upright, can participate in functional activities, and has not required any pain medication. The patient's functional vital capacity improved from 23% predicted preoperatively to 60% predicted postoperatively.

Conclusions

Patients with severe spinal deformity secondary to Escobar syndrome can be successfully treated surgically. We propose early surgical intervention in this group to prevent curve progression, restrictive lung disease, and the need for complex salvage procedures.
Effectiveness of an Acetabular Positioning Device in Primary Total Hip Arthroplasty
Authors: Padgett Douglas E. , Hendrix Stephen L. , Mologne Timothy S. , Peterson Drew A. , Holley Keith A.
Published: August 2005

To evaluate the efficacy of a commercially available acetabular positioning device, we performed a prospective evaluation of 40 consecutive patients undergoing primary total hip arthroplasty. All surgery was performed by the same surgeon, in the same operating room, and on the same operating table. The acetabular positioning device was designed to place the component in 45° of abduction. At 6 weeks, all radiographs were evaluated by 3 investigators not involved with the surgery. Each radiograph was evaluated by each reviewer on 3 separate occasions, blinded to the findings of the other reviewer to assess interobserver and intraobserver variability.

The mean cup abduction angle was 42.1°, with a range from 23° to 57° (SD 8.3°). Intraobserver and interobserver variability were 0.2 and 0.3°, respectively. The findings of this study demonstrate a wide variability in acetabular cup placement in primary total hip arthroplasty. We believe this is due to movement of the pelvis, which may occur during preparation, draping, and retracting during surgery. We feel surgeons should not rely solely on positioning devices when implanting the acetabular component in total hip arthroplasty. Identification of bone landmarks and determination of superolateral implant coverage noted on preoperative templating is advocated to improve the precision of component position.
Hospital for Special Surgery: Origin and Early History First Site 1863–1870
Authors: Levine David B.
Published: August 2005

Hospital for Special Surgery (HSS) originated as the Hospital for the Ruptured and Crippled (R&C) 142 years ago in New York City. As the first and only orthopaedic hospital of its kind in this country, it was located in the residence of its founder James Knight on Second Avenue, south of Sixth Street, and started with 28 inpatient beds for children but no operating facilities. The history of this institution has been documented in two books and occasionally published and unpublished papers. Many of these accounts have been limited by time, focus on a particular subject, or overall reviews. The emergence of such a specialized facility in the middle of the 19th century during a time of medicine in its infancy, our country at war and the city of New York racked in poverty, disease, civil riots, and political corruption is a story not necessarily appreciated in our day. The vision of one little-known physician and the cooperation and support of a small group of prominent New Yorkers and philanthropists were responsible for the origin of this hospital and particularly for its survival in such troubled times when most small hospitals of this period lasted only for a few years. Fortunately, almost all of the original Annual Reports of the Board of Managers, photographs, manuscripts, personal records, and newspaper clippings have been saved. They are now being collected, preserved, catalogued, and displayed in the newly formed HSS Archives from which this material has been taken.
A Shearing Osteochondral Fracture of the Humeral Head following an Anterior Shoulder Dislocation in a Child
Authors: Choi Yun Sun , Potter Hollis G. , Scher David M.
Published: August 2005

A dislocation of the shoulder joint is rare in children with an open physis. The fractures associated with an anterior dislocation generally reported in the literature have been Hill-Sachs lesions, avulsions of the greater tuberosity and glenoid fractures. We present a case of a previously unreported shearing osteochondral fracture, which is distinct from a classic Hill-Sachs lesion of the humeral head, in 12-year-old boy. The patient suffered a traumatic anterior shoulder dislocation with a spontaneous reduction along with this associated fracture. The fracture subsequently healed with no further evidence of persistent instability.
microRNA biogenesis and function in plants
Authors: Chen Xuemei
Published: August 2005

A microRNA (miRNA) is a 21–24 nucleotide RNA product of a non‐protein‐coding gene. Plants, like animals, have a large number of miRNA‐encoding genes in their genomes. The biogenesis of miRNAs in Arabidopsis is similar to that in animals in that miRNAs are processed from primary precursors by at least two steps mediated by RNAse III‐like enzymes and that the miRNAs are incorporated into a protein complex named RISC. However, the biogenesis of plant miRNAs consists of an additional step, i.e., the miRNAs are methylated on the ribose of the last nucleotide by the miRNA methyltransferase HEN1. The high degree of sequence complementarity between plant miRNAs and their target mRNAs has facilitated the bioinformatic prediction of miRNA targets, many of which have been subsequently validated. Plant miRNAs have been predicted or confirmed to regulate a variety of processes, such as development, metabolism, and stress responses. A large category of miRNA targets consists of genes encoding transcription factors that play important roles in patterning the plant form.
Proteasome comprising a β1 inducible subunit acts as a negative regulator of NADPH oxidase during elicitation of plant defense reactions
Authors: Lequeu José , Simon-Plas Françoise , Fromentin Jérome , Etienne Philippe , Petitot Anne-Sophie , Blein Jean-Pierre , Suty Lydie
Published: August 2005

Elicitation of defense reactions in tobacco by cryptogein, triggered a production of active oxygen species (AOS) via the NADPH oxidase, NtrbohD, and an accumulation of β1din, a defense induced β‐type subunit of 20S proteasome. The proteasome inhibitor, MG132, stimulated this AOS production. Tobacco cells transformed with sense constructs of β1din showed an inhibition of the AOS production following elicitin treatment, whereas the antisense transformed cells showed a strongly enhanced AOS production. In cells transformed with sense construct of β1din, the NtrbohD transcripts failed to be induced by cryptogein as observed in control and antisense transformed cells. Conversely, in tobacco cells transformed with antisense constructs for NtrbohD, β1din transcripts remained at a low level after elicitation. These results constitute the first demonstration of proteasome comprising β1din acting as a negative regulator of NtrbohD and contributes to the regulation of AOS generation during plant defense reactions.
RNAi mechanisms in Caenorhabditis elegans
Authors: Grishok Alla
Published: August 2005

RNA interference (RNAi) is a form of gene silencing induced by double stranded RNA (dsRNA) that is processed into short interfering RNAs (siRNAs). RNAi can induce both post‐transcriptional and transcriptional gene silencing. In Caenorhabditis elegans, there are several distinct pathways where post‐transcriptional or/and transcriptional RNAi mechanisms are involved. RNAi in C. elegans is also systemic and heritable. This review will discuss RNAi related pathways, features of RNAi in C. elegans and possibilities of endogenous gene regulation by RNAi.
Molecular and therapeutic aspects of varicella–zoster virus infection
Authors: Quinlivan Mark , Breuer Judith
Published: August 2005

Varicella–zoster virus (VZV) is a highly species-specific member of the Herpesviridae family. The virus exhibits multiple cell tropisms, infecting peripheral blood mononuclear cells and skin cells before establishing latency in sensory neurons. Such tropisms are essential both for primary infection, which manifests itself as chickenpox (varicella), and subsequent reactivation to cause herpes zoster (shingles). The highly cell-associated nature of the virus, coupled with its narrow host range, has resulted in the lack of an animal model that mimics its diseases in humans, thereby greatly hindering the study of events in VZV pathogenesis. Despite this, extensive studies both in vitro and in vivo in small-animal models have provided a fascinating insight into molecular events that govern VZV diseases. In addition, VZV has become the first human herpes virus for which a live attenuated vaccine has been developed.
Statistical distribution of tumuli on pahoehoe flow surfaces: Analysis of examples in Hawaii and Iceland and potential applications to lava flows on Mars
Authors: Glaze L. S. , Anderson S. W. , Stofan E. R. , Baloga S. , Smrekar S. E.
Published: August 2005

Spatial distributions of tumuli on lava flow surfaces can be quantitatively linked to subsurface inflation processes. Three distinct styles of flow emplacement are studied: (1) lava flows undergo inflation that changes as a function of space and time resulting in random spatial distributions of tumuli, (2) lava flows with preferred pathways result in systematic clustering of inflation features, and (3) established tubes or narrow pahoehoe flows produce chains of tumuli. Statistical analyses are required to distinguish between styles one and two. Comparison of the spatial distribution of tumuli on a portion of a lava flow at Mauna Ulu with the Poisson distribution indicates that tumuli are randomly distributed on the flow surface, typical of style one emplacement where small‐scale topographic variability and low slope influence development of preferred pathways that evolve over time. At Thrainsskjoldur, direct statistical comparisons to the Poisson spatial distribution are inconclusive but nearest‐neighbor analysis indicates significant clustering. An initially random spatial distribution is inferred that developed preferred pathways and systematic clustering of inflation features, as with style two. At Elysium Planitia on Mars, the flow margin is significantly deficient in inflation features, while away from the margin, the flow exhibits a random spatial distribution of tumuli typical of style one emplacement. The flow is interpreted as multiple units or a single flow that migrated in space during emplacement. At the 1843 flow on Mauna Loa, tumuli occur on a linear trend, consistent with style three emplacement.
Is the Indian summer monsoon stable against global change?
Authors: Zickfeld K. , Knopf B. , Petoukhov V. , Schellnhuber H. J.
Published: August 2005

The stability of the Indian summer monsoon is investigated by means of a box model of the tropical atmosphere. At the heart of this model is the moisture‐advection feedback which allows for the existence of two stable regimes: besides the “wet” summer monsoon, a stable state exists which is characterized by low precipitation. The model is employed for the identification of changes in the qualitative systems behavior in response to changes in boundary conditions. The most notable result is the occurrence of saddle‐node bifurcations against changes in those quantities which govern the heat balance of the system, i.e., the planetary albedo, the insolation, and the CO2 concentration. These findings are remarkable insofar as they indicate that anthropogenic perturbations of the planetary albedo, such as sulphur emissions and/or land‐use changes, or natural variations in insolation and CO2 concentration could trigger abrupt transitions between different monsoon regimes.
Thermodynamic and cloud parameter retrieval using infrared spectral data
Authors: Zhou Daniel K. , Smith William L. , Liu Xu , Larar Allen M. , Huang Hung‐Lung A. , Li Jun , McGill Matthew J. , Mango Stephen A.
Published: August 2005

High‐resolution infrared radiance spectra obtained from near nadir observations provide atmospheric, surface, and cloud property information. A fast radiative transfer model, including cloud effects, is used for atmospheric profile and cloud parameter retrieval. The retrieval algorithm is presented along with its application to recent field experiment data from the NPOESS Airborne Sounder Testbed – Interferometer (NAST‐I). The retrieval accuracy dependence on cloud properties is discussed. It is shown that relatively accurate temperature and moisture retrievals can be achieved below optically thin clouds. For optically thick clouds, accurate temperature and moisture profiles down to cloud top level are obtained. For both optically thin and thick cloud situations, the cloud top height can be retrieved with an accuracy of approximately 1.0 km. Preliminary NAST‐I retrieval results from the recent Atlantic‐THORPEX Regional Campaign (ATReC) are presented and compared with coincident observations obtained from dropsondes and the nadir‐pointing Cloud Physics Lidar (CPL).
Oceanic uptake and the global atmospheric acetone budget
Authors: Marandino C. A. , De Bruyn W. J. , Miller S. D. , Prather M. J. , Saltzman E. S.
Published: August 2005

In this study, direct measurements of the air/sea flux of acetone were made over the North Pacific Ocean. The results demonstrate that the net flux of acetone is into, rather than out of the oceans. The extrapolated global ocean uptake of 48 Tg yr−1 requires a major revision of the atmospheric acetone budget. This result is consistent with a recent reevaluation of acetone photodissociation quantum yields.
Senescing grass crops as regional sources of reactive volatile organic compounds
Authors: Karl T. , Harren F. , Warneke C. , de Gouw J. , Grayless C. , Fall R.
Published: August 2005

Grass crop species, rice and sorghum, that are widely grown in the southeastern Texas region were analyzed for release of biogenic volatile organic compounds (VOCs) in simulated leaf‐drying/senescence experiments. VOC release was measured by both online proton transfer reaction mass spectrometry (PTR‐MS) and proton transfer ion trap mass spectrometry (PIT‐MS) methods, and it was demonstrated that these two grass crops release a large variety of oxygenated VOCs upon drying under laboratory conditions primarily from leaves and not from stems. VOC release from paddy rice varieties was much greater than from sorghum, and major VOCs identified by gas chromatography PTR‐MS included methanol, acetaldehyde, acetone, n‐pentanal, methyl propanal, hexenol, hexanal, cis‐3‐hexenal, and trans‐2‐hexenal. The latter four VOCs, all C6 compounds known to be formed in wounded leaves, were the major volatiles released from drying rice leaves; smaller but substantial amounts of acetaldehyde were observed in all drying experiments. Online detection of VOCs using PIT‐MS gave results comparable to those obtained with PTR‐MS, and use of PIT‐MS with collision‐induced dissociation of trapped ions allowed unambiguous determination of the ratios of cis‐ and trans‐hexenals during different phases of drying. As rice is one of the largest harvested crops on a global scale, it is conceivable that during rice senescence releases of biogenic VOCs, especially the reactive C6 wound VOCs, may contribute to an imbalance in regional atmospheric oxidant formation during peak summer/fall ozone formation periods. A county‐by‐county estimate of the integrated emissions of reactive biogenic VOCs from sorghum and rice production in Texas suggests that these releases are orders of magnitude lower than anthropogenic VOCs in urban areas but also that VOC emissions from rice in southeastern coastal Texas may need to be included in regional air quality assessments during periods of extensive harvesting.
The neurochemical and behavioral effects of the novel cholinesterase–monoamine oxidase inhibitor, ladostigil, in response to L‐dopa and L‐tryptophan, in rats
Authors: Sagi Yotam , Driguès Noam , Youdim Moussa B H
Published: August 2005

The novel drugs, ladostigil (TV3326) and TV3279, are R and S isomers, respectively, derived from a combination of the carbamate cholinesterase (ChE) inhibitor, rivastigmine, and the pharmacophore of the monoamine oxidase (MAO) B inhibitor, rasagiline. They were developed for the treatment of comorbidity of dementia with Parkinsonism. In the present study, we determined the effects of these drugs on both aminergic neurotransmitter levels and motor behavioral activity in naïve and in L‐dopa‐ or L‐tryptophan‐induced rats.

Chronic treatment of rats with ladostigil (52 mg kg−1 for 21 days) inhibited hippocampal and striatal MAO A and B activities by >90%, increased striatal levels of dopamine and serotonin, and inhibited striatal ChE activity by ∼50%.

Chronic TV3279 (26 mg kg−1 for 21 days) similarly inhibited ∼50% of striatal ChE activity, but did not affect MAO activity or amine levels.

In sharp contrast to the inductive effect of the MAO A/B inhibitor, tranylcypromine (TCP), on stereotyped hyperactivity in response to L‐dopa (50 mg kg−1) or L‐tryptophan (100 mg kg−1), ladostigil completely inhibited these behavioral hyperactivity syndromes. Accordingly, acute rivastigmine (2 mg kg−1) and chronic TV3279 abolished the ability of TCP to initiate L‐dopa‐induced hyperactivity, while scopolamine (0.5 mg kg−1) reversed the inhibitory effect of chronic ladostigil on L‐dopa‐induced hyperactivity, suggesting that ladostigil may attenuate successive locomotion by activating central cholinergic muscarinic receptors.

Finally, while chronic ladostigil administration to naïve rats resulted in preserved spontaneous motor behavior, acute treatment with ladostigil decreased motor performance, compared to control animals. In contrast, chronic as well as acute treatments with TV3279 reduced spontaneous motor activity. Thus, the aminergic potentiation by ladostigil may counteract its cholinergic inhibitory effect on spontaneous motor behavior.

Our results suggest that potentiation of both aminergic and cholinergic transmission systems by ladostigil contributes equally to motor behavior performance, which is substantially impaired in comorbidity of dementia with Parkinsonism including dementia with Lewy bodies (DLB).

British Journal of Pharmacology (2005) 146, 553–560. doi:10.1038/sj.bjp.0706355
Induction of central signalling pathways and select functional effects in human platelets by β‐boswellic acid
Authors: Poeckel Daniel , Tausch Lars , Altmann Anja , Feißt Christian , Klinkhardt Ute , Graff Jochen , Harder Sebastian , Werz Oliver
Published: August 2005

We have recently shown that in polymorphonuclear leukocytes, 11‐keto boswellic acids (KBAs) induce Ca2+ mobilisation and activation of mitogen‐activated protein kinases (MAPK). Here we addressed the effects of BAs on central signalling pathways in human platelets and on various platelet functions.

We found that β‐BA (10 μM), the 11‐methylene analogue of KBA, caused a pronounced mobilisation of Ca2+ from internal stores and induced the phosphorylation of p38 MAPK, extracellular signal‐regulated kinase (ERK)2, and Akt. These effects of β‐BA were concentration dependent, and the magnitude of the responses was comparable to those obtained after platelet stimulation with thrombin or collagen.

Based on inhibitor studies, β‐BA triggers Ca2+ mobilisation via the phospholipase (PL)C/inositol‐1,4,5‐trisphosphate pathway, and involves Src family kinase signalling.

Investigation of platelet functions revealed that β‐BA (10 μM) strongly stimulates the platelet‐induced generation of thrombin in an ex‐vivo in‐vitro model, the liberation of arachidonic acid (AA), and induces platelet aggregation in a Ca2+‐dependent manner.

In contrast to β‐BA, the 11‐keto‐BAs (KBA or AKBA) evoke only moderate Ca2+ mobilisation and activate p38 MAPK, but fail to induce phosphorylation of ERK2 or Akt, and do not cause aggregation or significant generation of thrombin.

In summary, β‐BA potently induces Ca2+ mobilisation as well as the activation of pivotal protein kinases, and elicits functional platelet responses such as thrombin generation, liberation of AA, and aggregation.

British Journal of Pharmacology (2005) 146, 514–524. doi:10.1038/sj.bjp.0706366