bluuebunny/crossref_metadata_2025_split huggingface dataset:
Descending influences on escape behavior and motor pattern in the cockroach
Authors: Schaefer Paul L. , Ritzmann Roy E. 
Published: August 2002

AbstractThe escape behavior of the cockroach is a ballistic behavior with well characterized kinematics. The circuitry known to control the behavior lies in the thoracic ganglia, abdominal ganglia, and abdominal nerve cord. Some evidence suggests inputs may occur from the brain or suboesophageal ganglion. We tested this notion by decapitating cockroaches, removing all descending inputs, and evoking escape responses. The decapitated cockroaches exhibited directionally appropriate escape turns. However, there was a front‐to‐back gradient of change: the front legs moved little if at all, the middle legs moved in the proper direction but with reduced excursion, and the rear legs moved normally. The same pattern was seen when only inputs from the brain were removed, the suboesophageal ganglion remaining intact and connected to the thoracic ganglia. Electromyogram (EMG) analysis showed that the loss of or reduction in excursion was accompanied by a loss of or reduction in fast motor neuron activity. The loss of fast motor neuron activity was also observed in a reduced preparation in which descending neural signals were reversibly blocked via an isotonic sucrose solution superfusing the neck connectives, indicating that the changes seen were not due to trauma. Our data demonstrate that while the thoracic circuitry is sufficient to produce directional escape, lesion or blockage of the connective affects the excitability of components of the escape circuitry. Because of the rapidity of the escape response, such effects are likely due to the elimination of tonic descending inputs. © 2001 John Wiley & Sons, Inc. J Neurobiol 49: 9–28, 2001
A multilevel Newton–Krylov interface solver for multiphysics couplings of flow in porous media
Authors: Yotov Ivan 
Published: August 2002

AbstractA multiblock approach to modelling flow in porous media allows for coupling different physical and numerical models in a single simulation through the use of mortar finite elements. The resulting non‐linear algebraic system is reduced to a non‐linear interface problem which is solved by a full approximation scheme (FAS) multigrid with a Newton‐GMRES smoother. Copyright © 2001 John Wiley & Sons, Ltd.
An optimal control problem in estimating the optimal control force for the force vibration system
Authors: Huang Cheng‐Hung 
Published: August 2002

AbstractAn optimal control problem for the force vibration system based on the iterative regularization method, i.e. the conjugate gradient method (CGM), is examined to estimate the optimal control force in a damped system having time‐dependent system parameters such that the desire (or design) system displacements can be satisfied.It is assumed that no prior information is available on the functional form of the unknown control function in the present study, thus, it is classified as the function estimation.Numerical simulations are performed to test the validity of the present algorithm by using different types of the desire system displacements. Results show that an excellent estimation on the optimal control force can be obtained with arbitrary initial guesses within a couple of second's CPU time at Pentium III‐500 MHz PC. Copyright © 2001 John Wiley & Sons, Ltd.
Changes in mRNA for ryanodine receptors after transient cerebral ischemia and tolerance induction
Authors: Dahl Christina , Diemer Nils Henrik 
Published: August 2002

AbstractDisturbance of Ca2+ homeostasis is assumed to precede ischemia‐induced neuronal death. Using the 4‐vessel occlusion model of cerebral ischemia and induction of ischemic tolerance in the rat, we studied the intracellular Ca2+ activated Ca2+ channel, the ryanodine receptor (RyR), by means of in situ hybridisation and immunohistochemistry. We found the level of RyR2 mRNA increased in CA1 and CA3 of the ischemic vulnerable hippocampus following 3 minutes of tolerance inducing ischemia, whereas 9 minutes of ischemia lead to an increased mRNA level in CA1 in contrast to a decrease in CA3. In ischemic tolerant animals (3 + 8.5 minutes of ischemia) the mRNA level was decreased in CA3. In all experimental groups, RyR1 mRNA remained unaltered, whereas RyR3 mRNA decreased in DG. Immunohistochemistry revealed no alterations of the RyR protein level in all the ischemic groups compared to sham‐operated animals. Taken together, these changes do not clarify if the RyR is involved in tolerance induction or in the degenerative process leading to ischemic delayed neuronal death.
Development of the practice environment scale of the nursing work index†‡
Authors: Lake Eileen T. 
Published: August 2002

AbstractFive subscales were derived from the Nursing Work Index (NWI) to measure the hospital nursing practice environment, using 1985–1986 nurse data from 16 magnet hospitals. The NWI comprises organizational characteristics of the original magnet hospitals. The psychometric properties of the subscales and a composite measure were established. All measures were highly reliable at the nurse and hospital levels. Construct validity was supported by higher scores of nurses in magnet versus nonmagnet hospitals. Confirmatory analyses of contemporary data from 11,636 Pennsylvania nurses supported the subscales. The soundness of the new measures is supported by their theoretical and empirical foundations, conceptual integrity, psychometric strength, and generalizability. The measures could be used to study how the practice environment influences nurse and patient outcomes. © 2002 Wiley Periodicals, Inc. Res Nurs Health 25:176–188, 2002
The great auk and the gannet: a prehistoric perspective on the extinction of the great auk
Authors: Serjeantson Dale 
Published: August 2002

AbstractArchaeological finds of the great auk, Alca impennis, and the northern gannet, Sula bassana, from prehistoric and historic coastal sites around the British Isles show the earlier distribution of these birds. They suggest that the great auk bred more widely in the eastern Atlantic than on the few breeding sites which are attested historically. Comparison between the two species suggests that the method of exploitation as well as the biology and behaviour of each contributed to the extinction of the former and the survival of the latter. Copyright © 2001 John Wiley & Sons, Ltd.
On the discontinuity of the costates for optimal control problems with Coulomb friction
Authors: Driessen Brian J. , Sadegh Nader 
Published: August 2002

AbstractThis work points out that the costates are actually discontinuous functions of time for optimal control problems with Coulomb friction. In particular these discontinuities occur at the time points where the velocity of the system changes sign. To our knowledge, this has not been noted before. This phenomenon is demonstrated on a minimum‐time problem with Coulomb friction and the consistency of discontinuous costates and switching functions with respect to the input switches is shown. Copyright © 2001 John Wiley & Sons, Ltd.
Phospholipid coated poly(lactic acid) microspheres for the delivery of LHRH analogues
Authors: Rasiel Aliza , Sheskin Tzviel , Bergelson Lev , Domb Abraham J. 
Published: August 2002

AbstractThe aim of this work was to develop alternative peptide‐loaded microspheres using liposphere formulation—a lipid based microdispersion system. This formulation represents a new type of lipid or polymer‐based encapsulation system developed for parenteral and topical drug delivery of bioactive compounds. Our strategy was to utilize the liposphere formulation to improve the entrapment efficiency and release profile of triptorelin and leuprolide [luteinizing hormone–releasing hormone (LHRH) analogues] in vitro. Peptides (2% w/w) were loaded into lipospheres contained of polylactic acid (PLA) or poly(lactic‐co‐glycolic acid) (PLGA) with several types of phospholipids. The effects of polymer and phospholipid type and concentration, method of preparation and solvents on the liposphere characteristics, particle size, surface and bulk structure, drug diffusion rate, and erosion rate of the polymeric matrix were studied. The use of L‐PLA (Mw = 2000) and hydrogenated soybean phosphatidylcholine (HSPC) with phospholipid–polymer ratio of 1 : 6 w/w, was the most efficient composition that formed lipospheres of particle size in the range of 10 µm with most of the phospholipid embedded on the particles surface. In a typical procedure, peptides were dissolved in N‐methyl‐2‐pyrrolidone (NMP), and dispersed in a solution of polymer and phospholipids in a mixture of NMP and chloroform with the use of 0.1% poly(vinyl alcohol) (PVA) as the emulsified aqueous medium. Uniform microspheres were prepared after solution was mixed at 2000 rpm at room temperature for 30 min. Using this formulation, the entrapment efficiency of LHRH analogues in lipospheres was up to 80%, and the peptides were released for more than 30 days. Copyright © 2002 John Wiley & Sons, Ltd.
Asymmetric hydrogenation ofo‐Cresol andm‐Cresol catalyzed by silica‐supported methylcellulose–L‐alanine–Pd complex
Authors: Huang Kai , Hu Jie , Huang Mei‐Yu , Jiang Ying‐Yan 
Published: August 2002

AbstractSilica‐supported methylcellulose–L‐alanine–palladium complex (SiO2‐MC–LA–Pd) has been prepared and found to be a high optically active catalyst for asymmetric hydrogenation of o‐cresol and m‐cresol to give (S)‐2‐methylcyclohexanone and (R)‐3‐methylcyclohexanone, respectively, at 25 °C and under an atmospheric hydrogen pressure. The optical yields of (S)‐2‐methylcyclohexanone and (R)‐3‐methylcyclohexanone amounted to 91.5 and 68.5%, respectively, when optimum Pd content in SiO2‐MC–LA–Pd complex, reaction temperature and solvent were selected. SiO2‐MC–LA–Pd catalyst also has shown high stability. The optical yields for (S)‐2‐methylcyclohexanone and (R)‐3‐methylcyclohexanone were kept over 90 and 60%, respectively, when the catalyst was reused several times. Moreover, SiO2‐MC–LA–Pd complex is an economical catalyst. The methylcellulose is an abundant natural biopolymer and the procedure for preparation of the complex is very simple. Copyright © 2001 John Wiley & Sons, Ltd.
Microstaging in cutaneous melanoma
Authors: Ruiter D. J. , Spatz A. , van den Oord J. J. , Cook M. G. 
Published: August 2002

AbstractRecent papers have addressed critical issues regarding the microstaging of cutaneous melanoma. They concern the new staging proposal by the American Joint Committee on Cancer (AJCC), the presentation of new prognostic models than seem applicable in daily practice, and new immunohistochemical findings than demonstrate prognostic information independently of the conventional major factors. These issues are commented on by the Pathology Committee of the EORTC Melanoma Group. Copyright © 2001 John Wiley & Sons, Ltd.
Ki‐ras mutation type and the survival benefit from adjuvant chemotherapy in Dukes' C colorectal cancer
Authors: Gnanasampanthan G. , Elsaleh H. , McCaul K. , Iacopetta B. 
Published: August 2002

AbstractKi‐ras mutations are associated with an increased risk of relapse and death in colorectal cancer (CRC) patients, with some mutations being more aggressive than others. The present study examined the predictive value of different Ki‐ras mutation types in a retrospective series of 430 Dukes' C stage CRC patients, of whom 208 (48%) had received adjuvant chemotherapy with 5‐fluorouracil/levamisole or 5‐fluorouracil/leucovorin. A total of 140 mutations were detected, the majority (58%, 81/140) being glycine to aspartate mutations in codons 12 and 13. Glycine to valine mutations in codon 12 (14%, 20/140) and other less frequent, non‐specified mutation types (28%, 39/140) accounted for the remaining mutations. Kaplan–Meier survival analysis revealed that both Ki‐ras wild‐type and mutant patient groups derived significant survival benefit from chemotherapy. However, when patients were stratified according to the type of mutation, those with non‐aspartate mutations appeared to gain more benefit from this treatment than those with aspartate mutations. Multivariate analysis that included other possible predictive factors in Dukes' C CRC (tumour site, patient sex, TP53 mutation) demonstrated that non‐aspartate mutations in particular were associated with a significant survival benefit from chemotherapy (HR=0.11, 95% CI: 0.04–0.30, p<0.001). These results suggest that the type of Ki‐ras mutation could be a clinically useful molecular marker for the identification of CRC subgroups that are likely to benefit from 5‐fluorouracil‐based adjuvant chemotherapy. Copyright © 2001 John Wiley & Sons, Ltd.
Liquid chromatography–mass spectrometry analysis of propolis
Authors: Midorikawa Kiyoshi , Banskota Arjun H. , Tezuka Yasuhiro , Nagaoka Takema , Matsushige Katsumichi , Message Dejair , Huertas Alfredo A. G. , Kadota Shigetoshi 
Published: August 2002

AbstractThe composition of propolis, a resinous hive product collected by honeybees from various plant sources, depends on various factors such as season and vegetation of the area. Based on standards (either isolated from Brazilian propolis or reported from propolis) including chromane, diterpenes and phenolic compounds, different Brazilian propolis were analysed by LC‐MS in order to determine their chemical constituents. Dicaffeoylquinic acids were detected in almost all water extracts of Brazilian propolis, whereas diterpenes, flavonoids and prenylated phenolic compounds were found in their methanol extracts. Based on the identified chemical constituents and their biological activities, it was determined that the quality of Brazilian propolis could be directly related to the phenolic constituents. Moreover, Baccharis dracunculifolia was concluded to be an important source of Brazilian propolis. Propolis samples from Peru, China and the Netherlands were also studied. Copyright © 2001 John Wiley & Sons, Ltd.
Interval between insulin injection and meal in relation to glycated haemoglobin
Authors: Baker E. Ahmed Abu , Badgandi Mohan , Home Philip D. 
Published: August 2002

AbstractPeople who use an insulin regimen with pre‐meal short‐acting human insulin are usually recommended to inject insulin 20–40 min before the meal. It is a widespread impression, however, that most insulin‐treated diabetic patients do not follow such recommendations and inject their pre‐meal insulin preparation with an interval shorter than advised. The aim of the present study was to evaluate the timing of pre‐meal insulin injections, and to assess any relationship of the timing of pre‐meal insulin to overall blood glucose control, together with effects of age, sex, type and duration of diabetes. We studied 179 insulin‐treated diabetic patients, advised in accordance with local protocols to take their pre‐meal insulin injections 20 min or more before meals, using a short exploratory questionnaire. Patients answered one question about the timing of their pre‐meal insulin injection in relation to each main meal. In addition, physicians provided information on the patient's medical and diabetes history and blood glucose control from the medical records. Twenty‐seven per cent of patients reported having their pre‐meal insulin injection 0–5 min before meals, and 31% 6–10 min before meals. Twenty‐four per cent reported an 11–20 min interval, and 18% reported following the recommendations and taking their insulin 20 min or more before meals. HbA1c did not differ with pre‐meal injection interval. Age, sex, body mass index (BMI) and duration of diabetes had no effect on the injection–meal interval reported. In conclusion these results show that only a minority of insulin‐treated patients follow the recommendations regarding the timing of pre‐meal insulin injections. Blood glucose control as assessed by HbA1c is not obviously affected by the timing of pre‐meal insulin injection in relation to meals. Copyright © 2001 John Wiley & Sons, Ltd.
Improving the early management of blood glucose in emergency admissions with chest pain
Authors: Rutter Martin K , Wilcox Emily , Easton Joan , Skinner Jane , Taylor Roy 
Published: August 2002

AbstractHyperglycaemia is associated with a worse prognosis after myocardial infarction and good blood glucose control in the peri‐infarct period has been shown to improve outcome. Our primary study was undertaken with the aims of assessing the prevalence and management of hyperglycaemia in patients admitted with acute chest pain. Ninety‐three patients admitted to either Coronary Care (CCU) or Emergency Medical Admission Units (EMAU) with chest pain were studied and of these 14 (15%) had severe hyperglycaemia (>11.0 mmol/L). Blood glucose was not measured in seven (8%) patients and in only 1/14 (7%) patient were established guidelines for the management of hyperglycaemia applied. A revision of management protocol was undertaken and after 18 months we repeated the review of management of hyperglycaemia. Of 114 patients 22 (21%) had severe hyperglycaemia, blood glucose was not measured in ten (9%) and management guidelines were followed in 13 (65%).A major improvement in management of blood glucose in emergency admissions with chest pain has been demonstrated. Further staff education, discussion and review of protocol are indicated to improve and maintain performance on CCU and EMAU. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis and physical properties of sulfonated syndiotactic polystyrene ionomers
Authors: Li Hua‐Ming , Liu Jin‐Cheng , Zhu Fang‐Ming , Lin Shang‐An 
Published: August 2002

AbstractSulfonation of highly stereoregular syndiotactic polystyrene has been accomplished in 1,1,2‐trichloroethane and chloroform (60/40 v/v) mixed solvent. FTIR spectroscopy was used to confirm that the sulfonated syndiotactic polystyrene was the product of the sulfonation reactions. Sodium, potassium, zinc (II), manganese (II) and cobalt (II) salts of the sulfonated polymers exhibited behaviour indicative of strong interactions. FTIR spectroscopy and DSC data showed that the roles of the cation–anionic site interactions in alkali form and transition metal form ionomers are somewhat different. The DSC data also showed that the alkali metal cations had more pronounced effect on Tg than did the transition metal cations. In addition, the crystallization behaviour of the ionomers with a low degree of sulfonation also exhibited considerable differences in comparison with the neat syndiotactic polystyrene. The melting points (Tm) and the degree of crystallization (Xc) were significantly lowered by the presence of the sulfonic acid groups or the sulfonate metal groups. Moreover, the ionomers were more thermally stable and more hygroscopic than the unmodified polymer.© 2001 Society of Chemical Industry
Thermal and mechanical characterization of epoxy resins toughened using preformed particles
Authors: Day R J , Lovell P A , Wazzan A A 
Published: August 2002

AbstractPreformed, multilayer particles have been used to toughen an epoxy resin. The particles were formed by emulsion polymerization and consist of alternate glassy and rubbery layers, the outer layer having glycidyl groups to give the possibility of chemical bonding of the particles in the cured resin. Two variants of this type of particle were used, termed GM(47/15) and GM(47/37); both types have an overall diameter of 0.5 µm, but the former have a thicker rubbery layer. For comparison, acrylic toughening particles (ATP) with no surface functionality and a liquid carboxyl‐terminated butadiene–acrylonitrile (CTBN) rubber were used as toughening agents. The epoxy resin system consisted of a commercial diglycidyl ether of bisphenol A (Shell Epon 828) with diamino‐3,5‐diethyl toluene as hardener, two commercial sources of which were used, namely Ethacure‐100 (Albemarle SA) and DX6509 (Shell Chemicals). These hardeners contain a mixture of two isomers, namely 2,6‐diamino‐3,5‐diethyltoluene and 2,4‐diamino‐3,5‐diethyltolueneThermogravimetry in nitrogen shows that the preformed toughening particles begin to degrade at 230 °C, whereas the cured resin begins to degrade rapidly at 350 °C. Thus, even though the particles are less thermally stable than the cured resin, their degradation temperature is well above the glass transition temperature of the resin, and their use does not affect the thermal stability of the toughened materials at normal use temperatures.The performance of the toughening agents was compared using Ethacure‐100 as the hardener. The GM(47/15) and GM(47/37) toughening particles gave rise to a greater toughening effect than the ATP and the CTBN. For example, the fracture energies were: 0.26 kJ m−2 for the unmodified resin; 0.60 kJ m−2 for the resin toughened with CTBN; and 0.69 kJ m−2 for the resin toughened with the GM(47/15) particles. The ultimate tensile stress of the unmodified epoxy resin was 43 MPa, which increased to 55 MPa when 20 wt% of GM(47/15) toughening particles were added.The toughness of resins cured with the DX6509 hardener were superior to those obtained with the Ethacure‐100 hardener, most probably due to DX6509 producing a less‐highly‐crosslinked network. This highlights the sensitivity of the toughening process to the hardener used, even for hardeners of a similar nature.© 2001 Society of Chemical Industry
In vitro and in vivo degradation study on novel blends composed of polyphosphazene and polyester or polyanhydride
Authors: Qiu L Y 
Published: August 2002

AbstractPoly[bis(glycine ethyl ester)phosphazene] (PGP) was blended with poly(D,L‐lactide‐co‐glycolide) (80:20 by mole) (PLGA) and poly[sebacic anhydride‐co‐trimellitylimidoglycine)‐block‐poly(ethylene glycol)] (30:50:20 by mole) (PSTP) in various ratios using a solvent‐mixing technique. The in vitro degradation of polymer blends was examined by treatment in distilled water with or without lipase at 37 °C; the degradation rate of the blends could be regulated by adjusting the composition. PGP/PLGA (70:30 by wt) slabs took 120 days to disappear completely, while PGP/PSTP (70:30 by wt) needed only 20 days. Furthermore, Rhizopus delemer lipase showed the strongest acceleration activity on PGP/PLGA blends. The degree of enzymatic degradation was proportional to the percentage of PLGA in the blend. For comparison, the in vivo degradation of polymer blends was investigated by implanting them subcutaneously in the back of mice, some difference in degradation being observed.© 2002 Society of Chemical Industry
Effect of epoxy functionalized compatibilizer on the mechanical properties of low‐density polyethylene/plasticized tapioca starch blends
Authors: Sailaja R R N , Reddy A Prasad , Chanda Manas 
Published: August 2002

AbstractA series of low‐density polyethylene (LDPE) blends with varying proportions of plasticized tapioca starch have been used for the study of their mechanical properties. A functionalized epoxy resin, namely, poly(ethylene‐co‐glycidyl methacrylate) has been used as the compatibilizer. The impact and tensile properties have been measured by standard ASTM methods. The mechanical properties are seen to improve significantly with the addition of the epoxy compatibilizer, approaching values close to those of virgin LDPE. The scanning electron micrographs of the compatibilized blends show ductile failure which evidently contribute to improved mechanical properties.© 2001 Society of Chemical Industry