bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comparative Mechanical Study of 3 External Fixator Clamps
Authors: Gilley Robert S. , Bourgeault Craig A. , Wallace Larry J. , Bechtold Joan E. 
Published: August 2002

Objective—To compare external fixator clamps from Kirschner‐Ehmer (K‐E), Synthes, and Meynard with respect to 6 mechanical parameters.Study Design—A bench test of mechanical properties.Methods—Specially designed fixtures were used to mechanically test 6 clamps of each type at 2.5, 5.0, and 7.5 Newton‐Meters of clamp bolt‐tightening torque.Results—Components slipped axially and torsionally in the K‐E clamp at higher forces for all parameters except for clamp bolt axis pivot. No bolt axis pivot occurred with the Synthes clamp. Instead, the clamp plastically deformed at the fixator‐pin interface. This failure occurred at a higher applied torque than the pivot torque for other clamps. The Meynard clamp withstood significantly greater force than the K‐E clamp when torsion was applied to the clamp bolt axis in the clockwise direction. Pivot forces for the K‐E clamp were significantly higher than the Meynard clamp in the counterclockwise direction.Conclusions—Overall, the K‐E clamp was able to resist higher axial and torsional forces before slipping than the Meynard clamp or the Synthes clamp. The Synthes clamp was best able to resist torsion around the clamp bolt axis. Torsional resistance at the clamp‐fixator pin and clamp‐connecting bar interface was the weakest parameter of clamp mechanics.Clinical Relevance—The ability to resist motion within a clamp is related to fracture‐reduction stability. Knowledge of the mechanical properties of fixator clamps will improve a clinician's ability to apply rigid fixation.
Thermostable Polymers: Spectroscopies and Thermal Studies of Bismaleimide Systems in the Solid State
Authors: Grenier-Loustalot Marie Florence , Da Cunha Louis 
Published: August 2002

The study by DSC of two bismaleimide monomers (binary system BMI/BMI) mixed in different proportions led us to propose a phase diagram. The concept of a eutectic mixture having special thermal properties has thus been demonstrated. The eutectic melting temperatures are very interesting because they are much lower than that of the compound with the lowest melting point, facilitating the use of these monomers in the molten state. In the eutectic mixture, the two monomers were copolymerized and the resulting cross-linked networks characterized by 13C-NMR and FT-IR analysis. Another study by FT-IR of binary BMI/diamine systems has shown the importance of steric hindrance caused by the diamine or the BMI in the context of the two principal reactions of copolymerization and homopolymerization expected in these systems. In each mixture studied, the addition of diamine changed the melting points, with a general decrease, the first in all cases remaining lower than that of the diamine alone (the most meltable compound) and the second much lower than that of the pure bismaleimide monomer considered. It was noted that increasing hindrance on the diamine reduced the extent of the copolymerization reaction and favoured the homopolymerization reaction in the molten state.
Space Durable Polymer Threads
Authors: Schuler Peter , Haghighat Ross , Mojazza Hamid 
Published: August 2002

A unique polymer called TORTM is being developed for use in twisted and braided sewing threads that exhibits excellent space durability in comparison with other organic polymers. Existing organic polymer threads for applications in low Earth orbit (LEO) can suffer significant erosion from the combined effects of atomic oxygen and vacuum ultraviolet radiation which compromise their mechanical and physical properties over time [1–3]. Several types of thread used to stitch multilayer insulation (MLI) blankets have limited lifespans due to these environmental effects. In ground-based testing conducted at Marshall Space Flight Center, TOR threads showed much lower mass loss, and retained significantly more strength after AO simulation than many competing materials. This paper discusses the processing of TOR into fibres, the braiding of TOR around an inner Kevlar® core, characterization of the fibre to date, and potential applications for this product.
Synthesis and Properties of High-Molecular-Weight Poly(L-Lactic Acid) by Melt/Solid Polycondensation under Different Reaction Conditions
Authors: Moon Sung-Il , Taniguchi Ikuo , Miyamoto Masatoshi , Kimura Yoshiharu , Lee Chan-Woo 
Published: August 2002

The melt/solid polycondensation of L-lactic acid (LA) was successfully conducted using a binary catalyst system comprising tin dichloride hydrate and p-toluenesulfonic acid (TSA). First, a thermal oligocondensate of LA with a degree of polymerization of eight was mixed with the binary catalyst and subjected to melt polycondensation at 180°C for 5 h to obtain a melt polycondensate with an average molecular weight of 13 000 Da. This melt polycondensate was then heat treated at 105°C for 2 h and subjected to solid-state polycondensation under various conditions to obtain a high-molecular-weight polymer of poly(L-lactic acid) (PLLA). In a typical case, the solid-state reaction was performed by raising the temperature from 130 to 155°C, or at a constant temperature of 140 or 150°C. In the former case the molecular weight of PLLA increased linearly with the temperature increase, while in the latter case the molecular weight increased above 500 000 Da in a relatively short reaction time. The crystallization of the polycondensate was a key step of this polycondensation and the crystallinity of the PLLA product was well correlated with the increase in the molecular weight. This method can be a direct industrial method for the manufacture of PLLA from LA, which may potentially be an alternative to the currently adopted lactide method.
Automated Tow Placed LARC™-PETI-5 Composites
Authors: Hou T H , Belvin H L , Johnston N J 
Published: August 2002

LARC™-PETI-5 is a PhenylEthynyl-Terminated Imide resin developed at NASA Langley Research Center (LARC) during the 1990s. It offers a combination of attractive composite and adhesive properties. IM7/LARC™-PETI-5 composites exhibit thermal and thermo-oxidative stability typical of polyimides, superior chemical resistance and processability, excellent mechanical properties, toughness and damage tolerance. It was selected for study in the High Speed Research program aimed at developing technologies for a future supersonic aircraft, the High Speed Civil Transport, with a projected life span of 60 000 h at a cruise speed up to March 2.4. Robust autoclave processing cycles for LARC™-PETI-5 composites have been thoroughly designed and demonstrated, which involved hand lay-up of solvent-ladened ‘wet’ prepregs. However, this type of processing is not only costly but also environmentally unfriendly. Volatile management and shrinkage could become serious problems in the fabrication of large complex airframe structural subcomponents. Robotic tow placement technology utilizing ‘dry’ material forms represents a new fabrication process which overcomes these deficiencies. This work evaluates and compares mechanical properties of composites fabricated by heated head automated tow placement (dry process) with those obtained by hand lay-up/autoclave fabrication (wet process). Thermal and rheological properties of the robotically as-placed uncured composites were measured. A post-cure cycle was designed due to the requirement of the PETI-5 resin for a 370 °C/1 h hold to reach full cure, conditions which cannot be duplicated during heated head robotic placement. Mechanical properties such as 0° flexural strength and modulus, open hole tensile and compressive strength and moduli, reduced section compression dogbone compressive strength, and modified zippora-medium small (MZ-MS) tensile and compressive properties were obtained on the post-cured panels. These properties compared favourably with those obtained from the wet process.
Processing and Properties of IM7/LARC ™ -RP46 Polyimide Composites
Authors: Hou T H , Wilkinson S P , Johnston N J , Pater R H , Schneiderk T L 
Published: August 2002

LARC™-RP46 resin system is a PMR type polyimide and is prepared by replacing methylenedianiline in the PMR-15 composition with 3,4′-oxydianiline. This resin system retains the same processing characteristics as PMR-15 but also offers enhanced fracture toughness. Rheological measurements were conducted on pre-imidized LARC™-RP46 moulding powder subjected to various ramp and hold temperature schemes. Adequate flow properties were found with theoretical (formulated) molecular weight 6 ≤1500 g mol−1. Critical transition temperatures for optimizing the process cycle were identified. They included the resin softening point, the imidization reaction peak, the isomerization reaction peak and the gelation point. Utilizing this information, 1.72 × 10 6 Pa (250 psi) cure cycles were designed for B-staged (dry) and unstaged (wet) prepregs. Composite laminates were fabricated which exhibited excellent consolidation and a void content below 0.1–0.2% as measured by image analysis. IM7/LARC™-RP46 exhibited higher composite mechanical properties than IM7/PMR-15. Short-beam shear strength, flexural strength and flexural modulus were measured at room temperature, 93, 150 and 177 °C. Composite engineering properties were also obtained including longitudinal tension, logitudinal compression, interlaminar shear, short block compression, open hole compression (OHC) and compression strength after impact (CAI). Excellent longitudinal tensile and compressive strengths were obtained and the CAI strength was 40% higher than that for PMR-15. Over 80% retention of all RT strengths were noted at 177 °C.
The relationship between social problem‐solving and bullying behaviour among male and female adult prisoners
Authors: Ireland Jane L. 
Published: August 2002

AbstractThe association between social problem solving and bullying behaviour among adult male and female prisoners is presented. A total of 210 male and 196 female prisoners were categorised into four groups: pure bullies, pure victims, bully/victims, and those not involved in bullying or victimisation. Prisoners completed a questionnaire that presented them with different bullying scenarios and were asked to suggest ways of dealing with each. Female bully/victims produced significantly more solutions in response to theft‐related bullying than male bully/victims. There were no further significant group or gender differences in the number of solutions generated. The bully group favoured aggressive responses for all scenarios. Males reported more aggressive responses than females. The results are discussed with reference to the environment in which the social problem solving is taking place and highlights the importance of distinguishing between the different groups involved in bullying. Aggr. Behav. 27:297–312, 2001. © 2001 Wiley‐Liss, Inc.
Pre‐school children remembering unpleasant events: complying with the unwritten rules of an invisible game
Authors: Sjöberg Rickard L. 
Published: August 2002

AbstractForty‐eight children between the ages 5 and 7 were as part of a standardized interview asked whether they had ever had the impression that they had met a ghost. Twenty‐six children were explicitly told to separate fantasy and reality when answering, whereas the remaining children were not. This instruction significantly reduced the number of alleged encounters with ghosts. It is concluded that children who are asked whether they have been part of events which they regard as fantastical might perceive the rules by which fantasy and reality should be separated as temporarily altered by the interviewer. Copyright © 2001 John Wiley & Sons, Ltd.
Pulmonary leukostasis: Role of perfusion lung scan in diagnosis and follow up
Authors: Szyper‐Kravitz M. , Strahilevitz J. , Oren V. , Lahav M. 
Published: August 2002

AbstractA patient with hyperleukocytic myelomonocytic leukemia who presented to the emergency room with sudden pleuritic chest pain and dyspnea is reported. Clinical manifestations included dyspnea tachypnea and hyperventilation. Blood gas analysis revealed hypoxemia, hypocarbia, and respiratory alkalosis. Chest X ray was normal, and perfusion lung scan revealed a diffuse vascular occlusive pattern compatible with pulmonary leukostasis. The patient underwent immediate leukapheresis with subsequent mitigation of symptoms. A second perfusion lung scan showed evidence of significant improvement. To our knowledge this is the first published case of hyperleukocytosis presenting with pulmonary leukostasis that was successfully diagnosed and followed by serial perfusion lung scan. Am. J. Hematol. 67:136–138, 2001. © 2001 Wiley‐Liss, Inc.
Thiotepa, busulfan, and cyclophosphamide as a preparative regimen for allogeneic transplantation for advanced myelodysplastic syndrome and acute myelogenous leukemia
Authors: Bibawi Samer , Abi‐Said Dima , Fayad Luis , Anderlini Paolo , Ueno Naoto T. , Mehra Rakesh , Khouri Issa , Giralt Sergio , Gajewski James , Donato Michelle , Claxton David , Braunschweig Ira , van Besien Koen , Andreeff Michael , Andersson Borje S. , Estey Elihu H. , Champlin Richard , Przepiorka Donna 
Published: August 2002

AbstractSixty‐two adults underwent marrow or blood stem cell transplantation from an HLA‐matched related donor using high‐dose thiotepa, busulfan, and cyclophosphamide (TBC) as the preparative regimen for treatment of advanced myelodysplastic syndrome (MDS) (refractory anemia with excess blasts with or without transformation) or acute myelogenous leukemia (AML) past first remission. All evaluable patients engrafted and had complete donor chimerism. A grade 3–4 regimen‐related toxicity occurred in eight (13%) patients, and a diagnosis of MDS was the only independent risk factor for grade 3–4 regimen‐related toxicity (hazard ratio 9.25,P= 0.01). Day‐100 treatment‐related mortality (TRM) was 19%. Poor‐prognosis cytogenetics increased the risk of day‐100 TRM (hazard ratio 11.4,P= 0.003), and use of tacrolimus for graft‐versus‐host disease prophylaxis reduced the risk of day‐100 TRM (hazard ratio 0.13,P= 0.027). For all patients, the three‐year relapse rate was 43% (95% CI, 28%–58%). Refractoriness to conventional induction chemotherapy prior to transplantation was an independent risk factor for relapse (hazard ratio 10.8,P= 0.02). Three‐year survival was 26% (95% CI, 14%–37%); survival rates were 29% for those transplanted for AML in second remission, 31% transplanted for AML in relapse, and 17% with MDS, and there were no independent risk factors for survival. TBC is an active preparative regimen for advanced AML. Patients with advanced MDS appeared to have a higher risk of toxicity and early mortality, and alternative preparative regimens should be considered for these patients. Am. J. Hematol. 67:227–233, 2001. © 2001 Wiley‐Liss, Inc.
Massive plasmocytosis due to methimazole‐induced bone marrow toxicity
Authors: Breier D.V. , Rendo P. , Gonzalez J. , Shilton G. , Stivel M. , Goldztein S. 
Published: August 2002

AbstractPancytopenia is a rare complication of the thionamide therapy reported secondary to aplastic anemia, the bone marrow being invariably hypocellular. We present a case of a 16‐year‐old female with Graves' disease who presented with massive bone marrow plasmocytosis mimicking multiple myeloma. The patient had already been on methimazole for a month when she was admitted to the Pediatric Unit with the diagnosis of sepsis. CBC revealed pancytopenia. Bone marrow aspirations showed hypocellular–normocellular bone marrow, 98% of plasma cells. At that time, MMI was discontinued and the patient was started on broad‐spectrum antibiotics, dexamethasone, and G‐CSF. Bone marrow aspiration day +4 still showed hypo‐normocellular marrow, with remaining 6% plasma cells. Myeloma screen was negative; ANC >1,000 at day +7, platelets >50,000 at day +24. Twenty‐four months after patient's discharge, her clinical condition, CBC, and bone marrow remained normal. To our knowledge this is the first report of pancytopenia due to MMI, where the usual hypoplasia found is replaced by massive plasmocytosis. Am. J. Hematol. 67:259–261, 2001. © 2001 Wiley‐Liss, Inc.
Modulation of MEK activity during G‐CSF signaling alters proliferative versus differentiative balancing
Authors: Baumann Michael A. , Paul Cassandra C. , Lemley‐Gillespie Susan , Oyster Marlo , Gomez‐Cambronero Julian 
Published: August 2002

AbstractPrevious studies of the granulocyte colony stimulating factor (G‐CSF) receptor have demonstrated that discrete signals direct proliferative and maturation signaling. Receptor deletion/mutant studies have shown that although activation of the ras‐mitogen activated protein (MAP) kinase pathway is necessary for G‐CSF directed proliferation, it is not necessary for maturation induced by this cytokine. We have assessed the effects of selective inhibition or overexpression of MAP kinase kinase (MEK) in a cell line model of G‐CSF‐induced neutrophil progenitor growth. Using the human G‐CSF responsive MPD cell line, we specifically inhibited MEK using PD 98059 and also transfected MPD cells with a constitutively active MEK construct. We then exposed the cells to G‐CSF and assessed the effects of MEK inhibition and forced expression on proliferation and differentiation. Inhibition of MEK followed by G‐CSF stimulation consistently resulted in an early 2.5‐fold increase in morphologically differentiated neutrophils expressing CD11b and CD16 and containing lactoferrin over that produced by G‐CSF alone. MEK inhibition alone had little effect on the differentiation stage of these cells, although proliferation was impaired. Forced expression of activated MEK resulted in a three‐ to five‐fold decrease in differentiated, lactoferrin containing neutrophilic cells resultant from G‐CSF induction, and a commensurate increase in cell proliferation. These observations suggest that modulation of MAPK activation may be a control point for altering the balance between proliferation and differentiation in response to G‐CSF. Physiologically, this control is likely exerted by costimulatory cytokines. Am. J. Hematol. 68:99–105, 2001. Published 2001 Wiley‐Liss, Inc.
Treatment of hepatitis C related thrombocytopenia with interferon alpha
Authors: Rajan Sandeep , Liebman Howard A. 
Published: August 2002

AbstractThrombocytopenia is a common extrahepatic manifestation of hepatitis C (HCV) infection. Treatment with steroids may be effective, but can exacerbate the viral infection. Interferon alpha (INF) has documented efficacy in the treatment of HCV, but its use in the treatment of HCV thrombocytopenia is controversial. We treated eight patients with HCV‐related thrombocytopenia, who had platelet counts of fewer than 50 × 109/l (range: 16 to 46 × 109/L) with INF 3 MU SQ three times a week. Planned duration of treatment was 24 weeks. Five patients had no evidence of hepatic cirrhosis, three had cirrhosis, and two had palpable splenomegaly. Only three patients tolerated the full course of treatment, and all three had improvement in their platelet counts to greater than 50 × 109/l. Two other patients had improvement in platelet counts to more than 50 × 109/l with shorter duration of treatment (six and 16 weeks, respectively). The mean increase in platelet count in the five responders was 44 × 109/lL (range: 28 to 90 × 109/l). The average peak platelet count in the responders was 81 × 109/l (range: 62 to 136 × 109/l). Duration of response ranged from four to 18+ months, with the shortest responses observed in the two patients treated with a shorter course of INF. Response was independent of the presence of cirrhosis. Responding patients had improvement in hepatic transaminases, reduction in cryoglobulin and anticardiolipin antibodies, and HCV plasma RNA when tested. Relapse was associated with an increase in these laboratory markers of HCV infection. We conclude that INF can be an effective treatment in patients with HCV‐related thrombocytopenia. Am. J. Hematol. 68:202–209, 2001. © 2001 Wiley‐Liss, Inc.
Fat distribution in venezuelan children and adolescents estimated by the conicity index and waist/hip ratio
Authors: Pérez Betty , Landaeta‐Jiménez Maritza , Vásquez Maura 
Published: August 2002

AbstractThis study compares the conicity index (C) with the waist/hip ratio (WHR) in a cross‐sectional sample of Venezuelan children (n = 784 boys and n = 735 girls), 3 to 16 years of age. Distributions of C and WHR were compared in Box‐plot diagrams. Regression analysis was used to examine the relationship between indices by age and sex. Conicity captured more outliers in the distribution than WHR and explained 33% to 62% of the variability in WHR in three age groups. The influence was stronger in females during adolescence (R2 = 0.60, P < 0.05). According to the principle of C, most children presented a bi‐conical shape, which was more pronounced in boys than girls and which was indicative of a more central distribution of adiposity. These results are related, in part, to age and sex differences in body composition and to the earlier onset of the adolescent growth spurt in Venezuelan children. Am. J. Hum. Biol. 14:15–20, 2002. © 2002 Wiley‐Liss, Inc.
Estimation of height in elderly Japanese using region‐specific knee height equations
Authors: Knous Barbara Lohse , Arisawa Masako 
Published: August 2002

AbstractTwo knee height equations to predict standing height of Japanese elderly were cross‐validated with Joetsu City elders. One equation was derived with Hawaiian residents of Japanese ancestry and the other with elders from the Kumamoto Prefecture in Japan. Subjects included 40 men and 39 women free‐dwelling, healthy elders with mean ages of 68.0 ± 2.2 years and 68.0 ± 2.7 years, respectively. Heights of the subjects were representative of Japanese elderly. Experienced nurses, trained to measure knee height, also measured standing height with an automatic stadiometer. A pilot study refined measurement skills. Differences between actual and predicted heights for both equations were significant. Multiple linear regression was used to derive knee height equations specific for elderly males and females living in Joetsu City: women, 63.06 + (2.38 × knee height in cm) −(0.34 × age in years); men, 71.16 + (2.61 × knee height in cm) ‐ (0.56 × age in years). Geographic‐specific knee height equations for Japanese elderly and cross‐validation with other locations are suggested to facilitate the accurate use of knee height in nutritional assessment of Japanese elders. Am. J. Hum. Biol. 14:300–307, 2002. © 2002 Wiley‐Liss, Inc.
Demographic consequences of unpredictability in fertility outcomes
Authors: Leslie Paul , Winterhalder Bruce 
Published: August 2002

AbstractChild survival is probabilistic, but the unpredictability in family formation and completed family size has been neglected in the fertility literature. In many societies, ending the family cycle with too few or too many surviving offspring entails serious social, economic, or fitness consequences. A model of risk‐ (or variance‐) sensitive adaptive behavior that addresses long‐term fertility outcomes is presented. The model shows that under conditions likely to be common, optimal, risk‐sensitive reproductive strategies deviate systematically from the completed family size that would be expected if reproductive outcome is were predictable. This is termed the “variance compensation hypothesis.” Variance compensation may be either positive or negative, resulting in augmented or diminished fertility. Which outcome obtained is a function of identifiable social, economic, and environmental factors. Through its effect on fertility behavior, variance compensation has a direct bearing on birth spacing and completed fertility, and thereby on problems in demography and human population biology ranging from demographic transitions to maternal depletion and child health. Risk‐sensitive models will be a necessary component of a general theory of fertility. Am. J. Hum. Biol. 14:168–183, 2002. © 2002 Wiley‐Liss, Inc.