bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proprioceptors monitoring forces in a locust hind leg during kicking form negative feedback loops with flexor tibiae motor neurons
Authors: Sasaki Ken , Burrows Malcolm 
Published: January 2003

SUMMARYIn preparation for jumping and kicking, a locust slowly generates large forces in the femoral muscles of its hind legs and stores them in elastic distortions of the tendons and femoral cuticle. At the femoro—tibial joints, the semi-lunar processes are bent, the cuticle of the dorsal distal femur is crumpled, and the femur is expanded in a mediolateral direction. We have analysed whether these distortions are monitored by sense organs and whether the information they provide is used to limit the forces generated and thus prevent structural damage to the joint.The two sensory neurons comprising the lump receptor lie in a groove in the ventral part of the distal femur. The sensory neurons spike if force is applied to the flexor tendon when the joint is fully flexed, but not when it is extended. They also spike as the tendon of the flexor muscle slides into the ventral femoral groove when the tibia is fully flexed during the co-contraction phase of kicking. Their spike frequency correlates with the extent of bending of a semi-lunar process that provides a quantifiable measure of the joint distortions. If the tibia is not fully flexed, however, then muscle contractions still cause distortions of the joint but these are not signalled by sensory spikes from the lump receptor. The lump receptor,therefore, does not respond primarily to the joint distortions but to the movements or force in the flexor tendon.Contractions of the flexor tibiae muscle caused by spikes in individual flexor motor neurons can evoke spikes in sensory neurons from the lump receptor when the joint is fully flexed. In turn, the sensory neurons cause a hyperpolarisation in particular flexor motor neurons in a polysynaptic negative feedback loop. The lump receptor could, therefore, regulate the output of the flexor motor neurons and, thus, limit the amount of force generated during co-contraction. It may also contribute to the inhibition of the flexors at the end of co-contraction that allows rapid kicking movements to occur.
Robust balancing for rotating machines
Authors: Garvey S D , Friswell M I , Williams E J , Lees A W , Care I D 
Published: January 2003

The balancing of rotors divides broadly into two categories: balancing in situ and balancing in a balancing machine. In the latter case, the most common practice is to arrange balance corrections on the rotor such that the net excitations of each of the four in-plane rigid-body modes of the free rotor is zero by deploying balance corrections on two independent planes. In a small proportion of cases, the net excitations of the first pair of flexural modes are also zeroed using a third correction plane. This paper proposes that, when rotors are balanced in a balancing machine (not similar to the machine stator), substantially more utility can be gained from the balancing operation by combining a suitably weighted account of the specific balancing requirements of the machine with knowledge of the expected machine characteristics than can be achieved by ignoring this knowledge. A single cost function is established based on a numerical model of the machine. Then, depending on circumstances, either the expected value of this cost function or its worst possible value can be minimized. The methods proposed require that relatively detailed knowledge of the distribution of residual unbalance be obtained experimentally. The paper briefly discusses some practical methods for how such information might be extracted. The definition of the cost function as a matrix quadratic form provides potentially valuable information about the necessary number and the optimal location of balance planes on a given rotor, and methods for determining an optimal set of balance planes are outlined.
Fundamental thermodynamics of fuel cell, engine, and combined heat and power system efficiencies
Authors: Barclay F J 
Published: January 2003

At the 2001 Grove Symposium on Fuel Cells attended by representatives of the world-wide fuel cell industry, fuel cells and fuel cells integrated with gas turbines were discussed. Combined heat and power (CHP) aspects were also discussed. Without exception, efficiency figures were irrationally based on the measured, Carnot-limited, lower calorific value (CV) of the fuel in energy units J. The rational basis, on the other hand, is the fuel chemical exergy (work units, Ws) calculated via an equilibrium diagram. In Joules experiment 1 Ws ≫ 1 J, where the irreversible ≫ must not become an = sign. A misnomer like potential energy (exergy) fits on the left of the diagram, CV on the right. Moreover credence was also given, at the symposium, to the popular misconception that a CHP system has an efficiency of the order of 80 per cent. An essential precursor to reading the paper is to grasp the theory of chemical equilibrium and equilibrium constants [3] as an aid to exploring the equilibrium diagram mentioned above.
A hybrid gas turbine cycle (Brayton/Ericsson): An alternative to conventional combined gas and steam turbine power plant
Authors: Frost T H , Anderson A , Agnew B 
Published: January 2003

A hybrid gas turbine cycle is proposed based on the conventional Brayton cycle for the high-temperature heat addition process while adopting the Ericsson cycle for the low-temperature heat rejection process. It thus incorporates the thermodynamic advantages of a combined gas and steam turbine (CCGT) cycle without the irrevcrsibilities of the boiler and the ancillarics of the steam turbine/condenser plant. Thermodynamic analysis shows that a similar overall thermal efficiency as current CCGT plant (i.e. 0.54) would be achieved at a maximum gas temperature of 1311 °C if polytropic efficiencies of 0.90 for compression and expansion could be realized and if a maximum temperature of 77 °C was obtained during isothermal compression in the bottoming Ericsson cycle. A novel method of achieving multistage isothermal compression using heat pipe technology is proposed.
A two-dimensional Navier—Stokes inverse solver for compressor and turbine blade design
Authors: Demeulenaere A , Léonard O , Van den Braembussche R 
Published: January 2003

A two-dimensional viscous inverse method for the design of compressor and turbine blades is presented. It iteratively modifies an initial geometry until a prescribed pressure distribution is reached on the blade surface. The method solves the time-dependent Navier—Stokes equations in a numerical domain of which some boundaries (the blade walls) move during the transient part of the computation. The geometry modification algorithm is based on the transpiration principle: a normal velocity distribution is computed from the difference between the actual and prescribed pressure distributions, and is used to modify the blade shape. A time iteration is then performed on this new blade shape, taking into account the grid movement during the time stepping. A two-dimensional upwind finite-volume Navier—Stokes solver has been developed. The multiblock strategy allows for a selective concentration of the discretization points in the zones of higher gradients. Applications to turbine and compressor blade design illustrate the accuracy of the flow computation, the capabilities and efficiency of the inverse method.
Effectiveness of treatment of tonsillopharyngitis: comparative study
Authors: Abdul-Baqi Khader J. , Shakhatreh Farouk M. N. 
Published: January 2003

This study was performed to find out the effectiveness of three different treatments of patients having acute tonsillopharyngitis. Three groups of patients were selected (50 patients in each group). Group I received one antibiotic according to the result of culture and sensitivity test, while groups II and III received two antibiotics or one antibiotic respectively without a culture and sensitivity test. Diagnosis was based on the acutely subjective symptoms of sore throat and positive clinical examination findings. The effectiveness of treatment in group I (96 per cent) was statistically significant (p<0.05) and higher than group II (82 per cent) and group III (74 per cent), while the difference between group II and III was not statistically significant (p>0.05).Our findings demonstrate that a culture and sensitivity test of the throat swab is necessary before treating acute tonsillopharyngitis. It was suggested that there should be appropriate selection of antibiotics to preserve normal flora, avoidance antibiotics for viral infections, patient compliance with prescription and educational programmes directed at patients and physicians. All of these measures would assist in reducing the volume of antibiotic use, bacterial resistance and the overall cost of treatment of tonsillopharyngitis.
Cervical node metastases in oropharyngeal squamous cell carcinoma: prospective analysis of prevalence and distribution
Authors: Jose Jemy , Coatesworth Andrew P. , Johnston Colin , MacLennan Ken 
Published: January 2003

The treatment of cervical lymph node metastases is an important part of the management of oropharyngeal squamous cell cancer. Metastases are already clinically present in 61 per cent (+ or −2.6 per cent) of patients at presentation. Previous studies concerning the prevalence and distribution of neck node metastases in oropharyngeal carcinoma have been retrospective, and little or no information is available about the histopathological methods used.This study has prospectively analysed 85 neck dissection specimens in 72 consecutive patients with squamous cell carcinoma of the oropharynx, both with clinically N0 and N+ve necks, to identify the prevalence and distribution of cervical metastases. We have used a technique to separate the neck dissection into nodal levels per-operatively, and then embedded the entire specimen for histological examination to avoid missing metastatic disease in small lymph nodes (<3mm diameter).
Microvascular free tissue reconstruction following extirpation of head and neck tumour: experience towards an optimal outcome
Authors: Lam L. K. , Wei William I. , Chan Vana S. H. , Ng Raymond W. M. , Ho W. K. 
Published: January 2003

Familiarity with four types of free tissues transfers allows appropriate reconstruction of most defects in the head and neck region functionally and aesthetically. These include jejunal graft, radial forearm, rectus abdominus myocutaneous and fibula osteocutaneous flaps. Free colonic and gastric patches were used occasionally.We report our experience of 215 free tissue transfers for reconstruction of defects in the head and neck region after tumour extirpation.The overall success rate was 94 per cent. The commonest cause of failure was related to arterial inflow (70 per cent). Three patients died in hospital, but their mortality was not related to the tissue transfers. Complications due to free tissue transfer at both the donor and recipient sites were few and manageable.The co-operation between the two surgical teams, together with the timely application of suitable salvage procedures, contribute to an optimal outcome.
Synthesis and molecular structure of 2,4,6‐tri[bis(diisopropylamino)boryl(methylamino)]borazine, [(NiPr2)2B(Me)N]3B3N3H3
Authors: Toury Bérangère , Cornu David , Lecocq Sylvain , Miele Philippe 
Published: January 2003

AbstractReaction of bis(diisopropylamino)(methylamino)borane, (NHiPr)2B(NHMe), with 2,4,6‐trichloroborazine (ClBNH)3 affords 2,4,6‐tri[bis(diisopropylamino)boryl(methylamino)]borazine, 2,4,6‐[(NiPr2)2B(Me)N]3B3N3H3, which is the first boryl‐borazine structurally characterized. According to the X‐ray single crystal structure and the chemical shifts of 11B NMR resonances of boron atoms, compared with the aminoborane and borazine analogs, the borazine and boryl π‐systems are not coplanar either in the solid state or in organic solution. Copyright © 2002 John Wiley & Sons, Ltd.
Order–disorder phenomena in crystalline phases of compounds E(XMe3)4 where E = C, Si, Ge and X = Si, Sn
Authors: Helluy Xavier , Sebald Angelika 
Published: January 2003

AbstractWe discuss the dynamic solid‐state properties of crystalline phases E(XMe3)4 as seen by solid‐state NMR and powder X‐ray diffraction. In the first part we will qualitatively describe some of the NMR tools suitable for such investigations. In the second part we will give examples from the group of solid compounds E(XMe3)4 with E = C, Si, Ge and X = Si, Sn. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of crystallization conditions on spherulitic texture and tensile properties of sPS/PPO blends
Authors: Dutt G. , Kit K. M. 
Published: January 2003

AbstractIn the second study on melt‐miscible syndiotactic polystyrene (sPS) and poly(phenylene oxide) (PPO) blends, the effect of processing conditions on morphology, ultimate tensile properties, and the mode of fracture is reported. Bulk samples of the blends were molded and then crystallized from melt as well as from the quenched state at different temperatures. The spherulitic morphology of the melt‐crystallized blends, observed by scanning electron microscopy, revealed formation of complete, well‐developed spherulites whose texture increased in coarseness with increasing crystallization temperatures. In all the cold‐crystallized blends lamellar bundles formed a meshlike structure whose texture did not vary significantly with crystallization temperature. Depending on the crystallization temperature, 50/50 melt‐crystallized blends showed varying tensile properties and different modes of failure. In the samples with the largest amorphous domain size of 0.6 μm, the amorphous ellipsoids were cold drawn into fibrils during tensile loading and very high tensile strengths were recorded. The tensile properties for the other melt‐crystallized and all cold‐crystallized blends did not vary substantially with the changing crystallization temperature. The micrographs of the fractured surfaces of the melt‐crystallized blends suggested that, although intraspherulitic fracture occurred at low crystallization temperatures, interspherulitic fracture took place at high crystallization temperatures. The correlation of the morphology and mechanical properties suggests that melt‐miscible blends have good interfacial adhesion between phases and that, by varying composition and processing conditions, it might be possible to control amorphous domain sizes, which is critical in achieving better mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1984–1994, 2003
Kinetics of hydrolysis of polyethylene terephthalate pellets in nitric acid
Authors: Kumar Aanchal , Rao T. Rajeswara 
Published: January 2003

AbstractThe hydrolysis of polyethylene terephthalate (PET) pellets in nitric acid was investigated to determine the kinetic parameters. Experiments were conducted with cylindrical shaped pellets in 13M nitric acid at 80, 90, and 100°C respectively. Also, an experiment was conducted with a waste PET bottle sheet in 9.5M nitric acid at 100°C. The kinetics of the reaction was explained by the shrinking core model with surface chemical reaction as rate controlling step and accounting for surface area reduction due to the deposition of the product terephathalic acid (TPA) on the reaction surface. The activation energy for the reaction was found to be 135 kJ/mol. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87:1781–1783, 2003
Reaction and miscibility of two diepoxides with poly(ethylene terephthalate)
Authors: Fenouillot Françoise , Hedreul Claire , Forsythe John , Pascault Jean‐Pierre 
Published: January 2003

AbstractPoly(ethylene terephthalate) (PET) was melt‐blended at 270°C with two epoxy monomers, diglycidyl ether of bisphenol A (DGEBA) and 3,4‐epoxycyclohexyl‐methyl‐3,4‐epoxycyclohexyl carboxylate (ECY). Intermediate proportions of the epoxy in the range of 20–0.5 wt % were used. If the epoxy monomers were added in a high proportion (10–20%), a large fraction did not react with PET. Calorimetric experiments showed that the unreacted fractions of both epoxies were miscible with the amorphous phase of the polyester. Only one glass‐transition temperature was detected. It was depressed as the epoxy content was increased. The transition was broad when the PET component was crystalline, and it was narrow when the PET component was made amorphous by quenching of the blend. These features were confirmed by dynamic thermal mechanical analysis. As is often the case for crystalline blends, the crystallization and melting temperatures decreased when the proportion of the epoxy was increased. Concerning the reactivity of the epoxy with PET, the behavior differed according to the nature of the epoxy. The DGEBA monomer showed a low reactivity. It was not effective for the chain extension of PET, and no increase in the intrinsic viscosity was observed under the experimental conditions. However, some functionalization of the chain ends may be possible at a high concentration of the epoxy. ECY was more reactive, and the molecular weight of the processed PET increased, although the value of the commercial untreated polyester was not attained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1995–2003, 2003
Evaluation of a novel method to estimate absolute bioavailability of drugs from oral data
Authors: Hinderling Peter H. 
Published: January 2003

AbstractThe goal of this investigation was to evaluate the performance of a novel method allowing estimation of absolute bioavailability from oral data only. In contrast to the traditional method, which compares areas under the drug concentration time curves after oral and intravenous administration in subjects with normal renal function, the novel method uses total and renal clearance values following oral administration from subjects with varying renal functions to estimate bioavailability. The novel method can also provide estimates for nonrenal clearance.Published data on total clearance and renal clearance of drugs obtained from subjects with variable renal functions were collected, the novel method applied, estimates of bioavailability and nonrenal clearance obtained and compared with reported estimates by the traditional methods. In addition computations were performed to assess various factors that could possibly affect the reliability of the novel method.The results indicated that the novel method provides accurate estimates for bioavailability of drugs meeting the prerequisites: linear kinetics, predominant renal excretion in normals, absence of metabolic polymorphism and independence of bioavailability and nonrenal clearance from renal function. The average (standard deviation) of the prediction error and bias of the bioavailability estimates by the novel method was 7.8 (6.0) and −1.4 (9.8)%, respectively. The estimates for nonrenal clearance by the novel method were less accurate. The computations confirmed that the estimates by the novel method are sensitive to renal‐function dependent changes in nonrenal clearance and bioavailability and also depend on the extent of renal excretion of a drug.In conclusion, the novel method's main use is to diagnose absence or presence of changes in bioavailability and non‐renal clearance of drugs in populations with varying renal function. Copyright © 2002 John Wiley & Sons, Ltd.
Plasma concentration profiles of ketamine and norketamine after administration of various ketamine preparations to healthy Japanese volunteers
Authors: Yanagihara Yoshitsugu , Ohtani Michiteru , Kariya Satoru , Uchino Katsuyoshi , Hiraishi Teiko , Ashizawa Naofumi , Aoyama Takao , Yamamura Yoshikazu , Yamada Yasuhiko , Iga Tatsuji 
Published: January 2003

AbstractKetamine is known to provide analgesic effects without an anesthetic when administered in a low dose. We previously reported that a tablet containing ketamine had analgesic effects in patients with neuropathic pain. In the present study, we compared the plasma concentration profiles of the enantiomers of ketamine and its active metabolite, norketamine, up to 8 h after the administration of 20 mg of ketamine by injection, after the administration of two tablets containing 25 mg of ketamine, after the administration of two sublingual tablets containing 25 mg of ketamine, after the insertion of a suppository containing 50 mg of ketamine, and after the application of a nasal spray containing 25 mg of ketamine to three healthy volunteers. The plasma concentration of ketamine biexponentially declined after the administration by injection; the value of T1/2β for ketamine was approximately 120 min. The bioavailability of the tablet was estimated to be approximately 20%; the area under the plasma concentration–time curve, (AUC)0→8 h, of norketamine was approximately 500 ng h/ml in both enantiomers. The bioavailabilities of the sublingual tablet and the suppository were estimated to both be approximately 30%; the AUC0→8 h of norketamine was 280–460 ng h/ml in both enantiomers. The plasma concentration profiles of the sublingual tablet and the suppository were almost similar to that of the tablet. The bioavailability of the nasal spray was estimated to be approximately 45%, which was the highest value among the preparations tested, and the AUC0→6 h of norketamine was low (approximately 100 ng h/ml) in both enantiomers. These pharmacokinetic findings suggested that all of the ketamine preparations tested in this study may be useful for the alleviation of neuropathic pain. We propose that the type of ketamine preparation should be selected in accordance with the patient's disease condition and the required dosage amount of ketamine. Copyright © 2002 John Wiley & Sons, Ltd.
Characteristics of the gastric pH profiles of unfed and fed cynomolgus monkeys as pharmaceutical product development subjects
Authors: Kondo Hiromu , Shinoda Tatsuki , Nakashima Hiroshi , Watanabe Takashi , Yokohama Shigeharu 
Published: January 2003

AbstractGastric pH is an important factor which significantly affects the dissolution of drugs, and therefore their bioavailability. In this study, the gastric pHs were measured directly with a miniature pH electrode inserted through the nostril into the body of the stomach of cynomolgus monkeys. Results from three separate sets of measurements using the same male monkeys indicated that the median gastric pH profiles of unfed monkeys were low, fluctuating between pH 1 and pH 3. However, the median gastric pHs in fed monkeys given about 108 g of a biscuit‐type solid food, which are commonly provided, shifted toward a more neutral range between pH 5 and pH 7, and remained in this range for about 9 h. This result contrasted with reported results for humans after eating a standard meal, which showed a neutral range between pH 5 and pH 7 for a brief period. Consequently, these results indicate that although the gastric pH of unfed cynomolgus monkeys is similar to that of fasting humans, there is a great difference in the gastric pH profiles between humans and monkeys after eating, which suggests that further studies are needed to establish optimal feeding conditions for bioavailability studies in monkeys. Copyright © 2002 John Wiley & Sons, Ltd.