bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proteases from Trypanosoma brucei brucei
Authors: Troeberg Linda , Pike Robert N. , Morty Rory E. , Berry Ronald K. , Coetzer Theresa H. T. , Lonsdale‐Eccles John D. 
Published: August 2004

African trypanosomes contain proteases that may be released into the bloodstream of their infected hosts. This paper describes a novel, combined isolation of a cysteine proteinase (called trypanopain‐Tb) and a serine oligopeptidase (which we call oligopeptidase‐Tb) from Trypanosoma brucei brucei, as well as a comparison of the activities of these two enzymes against several host regulatory molecules.The enzymes differed in various respects. Firstly, purified trypanopain‐Tb was shown to readily cleave proteins such as gelatin maximally at acidic pH. In contrast, oligopeptidase‐Tb, which is optimally active at alkaline pH, did not hydrolyse proteins larger than 4 kDa. However, it readily hydrolysed various polypeptides, including neurotensin and atrial natriuretic factor.The interaction of the two enzymes with mammalian protease inhibitors also differed. Cystatins and α2‐macroglobulin effectively inhibited trypanopain‐Tb, with the Ki values for cystatin C and low‐molecular‐mass kininogen (≈10−11 M) predicting that trypanopain‐Tb is likely to be effectively controlled by these inhibitors if released into the host bloodstream. In contrast, oligopeptidase‐Tb was not inhibited by serpins or α2‐macroglobulin, suggesting that it may remain active if released into the host bloodstream. In support of these in vitro results, the blood of trypanosome‐infected rats displayed no trypanopain‐Tb‐like activity, but exhibited high oligopeptidase‐Tb‐like activity. Thus, while trypanopain‐Tb seems likely to be confined to an intracellular role within the parasite, oligopeptidase‐Tb has the potential to remain active in the host bloodstream and so contribute directly to pathogenesis.
Stimulant psychosis: systematic review
Authors: Curran Catherine , Byrappa Neetha , McBride Andrew 
Published: August 2004

BackgroundPsychosis associated with stimulant use is an increasing problem, but there is little research evidence about the nature of the problem and its management.AimsTo critically review the literature on stimulant psychosis and sensitisation.MethodSystematic review of studies that have investigated stimulant use and psychosis in humans. The main outcome measures were increases in psychosis with stimulant use, and differences between stimulant users and non-users.ResultsFifty-four studies met the inclusion criteria. Experimental studies show that a single dose of a stimulant drug can produce a brief increase in psychosis ratings (a ‘response’) in 50–70% of participants with schizophrenia and preexisting acute psychotic symptoms, unaffected by the presence of antipsychotic medication. Those with schizophrenia who do not have acute psychotic symptoms respond, but less frequently (30%). There has been little research into the longer-term effects of use.ConclusionsCompliance with antipsychotic medication by someone with schizophrenia will not prevent a relapse or worsening of psychotic symptoms if stimulants are used. Low-dose antipsychotic treatment may be beneficial in stimulant users, to prevent sensitisation.
Cell density and cortical thickness in Heschl's gyrus in schizophrenia, major depression and bipolar disorder
Authors: Cotter David , Mackay Daniel , Frangou Sophia , Hudson Lance , Landau Sabine 
Published: August 2004

SummaryThere is evidence that the superior temporal gyrus and Heschl's gyrus within it are implicated in schizophrenia. We investigated neuronal and glial cell density and cortical thickness within Heschl's gyrus, using the optical disector to estimate cell density within cortical layers 3 and 5 in tissue derived postmortem from people with diagnoses of major depressive disorder, schizophrenia and bipolar disorder, compared with normal controls (n=15 per group). No significant difference in neuronal or glial cell density or in cortical thickness was observed between the groups; our findings therefore provide no support for the presence of cellular pathology within Heschl's gyrus in schizophrenia.
Admission patterns of patients with personality disorder
Authors: Dasgupta Pritha , Barber Joan 
Published: August 2004

Aims and MethodTo examine the prevalence and admission patterns of patients with personality disorder admitted to a Scottish general adult psychiatry service. We carried out a retrospective case-note study of patients identified from the computerised patient administration system. A subgroup of patients was identified as having a longer in-patient stay. Their admission pattern over the preceding 4 years was studied further.ResultsSixty-two of 844 patients admitted had personality disorder. Thirty-nine had a primary diagnosis of personality disorder, 19 had an additional diagnosis of psychiatric disorder and 12 of alcohol or substance misuse. Within the subgroup admitted for longer in 2001, patterns of few/brief and numerous/often lengthy admissions were noted in earlier years.Clinical ImplicationsPersonality disorder occurs in approximately 7% of admissions to general adult psychiatry beds. Many have additional diagnoses of psychiatric disorder, or substance or alcohol misuse further complicating their treatment.
Inhalation induction with sevoflurane for electroconvulsive therapy: a case series
Authors: Palmer James , Khalil Mohsen , Meagher David 
Published: August 2004

Aims and MethodUntil 1999, the most common drug for induction of anaesthesia for electroconvulsive therapy (ECT) in the UK was methohexital. Cessation of production left few choices of induction agent. Increased use of sevoflurane in short procedures suggests that it might be suitable as a sole agent for anaesthesia in ECT. We therefore induced anaesthesia in five consecutive patients undergoing ECT to assess sevoflurane's potential for this use. We recorded vital signs, needle phobia, face-mask toleration, duration of induction, seizure duration and recovery variables.ResultsAnaesthesia was successfully induced in all patients without difficulty. One patient experienced mild hypoxia following the seizure. Seizure duration ranged from 24 to 72 seconds. Recovery times to eye opening and times to ‘ward’ fitness were acceptable.Clinical ImplicationsSevoflurane may be a suitable alternative for induction of anaesthesia for ECT.
Ground reaction forces in horses trotting up an incline and on the level over a range of speeds
Authors: Dutto Darren J. , Hoyt Donald F. , Cogger Edward A. , Wickler Steven J. 
Published: August 2004

SUMMARYAlthough the forces required to support the body mass are not elevated when moving up an incline, kinematic studies, in vivo tendon and bone studies and kinetic studies suggest there is a shift in forces from the fore-to the hindlimbs in quadrupeds. However, there are no whole-animal kinetic measurements of incline locomotion. Based on previous related research, we hypothesized that there would be a shift in forces to the hindlimb. The present study measured the force produced by the fore- and hindlimbs of horses while trotting over a range of speeds (2.5 to 5 m s–1) on both level and up an inclined (10%) surface.On the level, forelimb peak forces increased with trotting speed, but hindlimb peak force remained constant. On the incline, both fore- and hindlimb peak forces increased with speed, but the sum of the peak forces was lower than on the level. On the level, over the range of speeds tested, total force was consistently distributed between the limbs as 57% forelimb and 43%hindlimb, similar to the weight distribution of the horses during static weight tests. On the incline, the force distribution during locomotion shifted to 52% forelimb and 48% hindlimb.Time of contact and duty factor decreased with speed for both limbs. Time of contact was longer for the forelimb than the hindlimb, a finding not previously reported for quadrupeds. Time of contact of both limbs tended to be longer when traveling up the incline than on the level, but duty factor for both limbs was similar under both conditions. Duty factor decreased slightly with increased speed for the hindlimb on the level, and the corresponding small, predicted increase in peak vertical force could not be detected statistically.
Biomechanics of quadrupedal walking: how do four-legged animals achieve inverted pendulum-like movements?
Authors: Griffin Timothy M. , Main Russell P. , Farley Claire T. 
Published: August 2004

SUMMARYWalking involves a cyclic exchange of gravitational potential energy and kinetic energy of the center of mass. Our goal was to understand how the limbs of walking quadrupeds coordinate the vertical movements of the fore and hind quarters to produce these inverted pendulum-like movements. We collected kinematic and ground reaction force data from dogs walking over a range of speeds. We found that the fore and hind quarters of dogs behaved like two independent bipeds, each vaulting up and over its respective support limb. The center of mass moved up and down twice per stride, like a single walking biped, and up to 70% of the mechanical energy required to lift and accelerate the center of mass was recovered via the inverted pendulum mechanism. To understand how the limbs produce these center of mass movements, we created a simple model of two independent pendulums representing the movements of the fore and hind quarters. The model predicted that the fore and hind quarter movements would completely offset each other if the fore limb lagged the hind limb by 25% of the stride time and body mass was distributed equally between the fore and hind quarters. The primary reason that dogs did not walk with a flat trajectory of the center of mass was that each fore limb lagged its ipsilateral hind limb by only 15% of the stride time and thereby produced time periods when the fore and hind quarters moved up or down simultaneously. The secondary reason was that the fore limbs supported 63% of body mass. Consistent with these experimental results, the two-pendulum model predicts that the center of mass will undergo two fluctuations per stride cycle if limb phase is less than 25% and/or if the total mass is not distributed evenly between the fore or hind quarters.
Distance and force production during jumping in wild-type and mutantDrosophila melanogaster
Authors: Zumstein Nina , Forman Oliver , Nongthomba Upendra , Sparrow John C. , Elliott Christopher J. H. 
Published: August 2004

SUMMARYIn many insects renowned for their jumping ability, elastic storage is used so that high forces can be developed prior to jumping. We have combined physiological, behavioural and genetic approaches to test whether elastic energy storage makes a major contribution to jumping in Drosophila.We describe a sensitive strain gauge setup, which measures the forces produced by tethered flies through their mesothoracic legs. The peak force produced by the main jumping muscle of female flies from a wild-type(Canton-S) strain is 101±4.4 μN [and this is indistinguishable from a second wild-type (Texas) strain]. The force takes 8.2 ms to reach its peak. The peak force is not affected significantly by altering the leg angle (femur–tibia joint angle) in the range of 75–120°, but the peak force declines as the leg is extended further.Measurements of jumping ability (distance jumped) showed that female Drosophila (with their wings removed) of two wild-type strains,Canton-S and Texas, produced jumps of 28.6±0.7 and 30.2±1.0 mm(mean ± s.e.m.). For a female wild-type Drosophila, a jump of 30 mm corresponds to a kinetic energy of 200 nJ on take-off (allowing 20% of the energy to overcome air resistance). We develop equations of motion for a linear force–time model of take-off and calculate that the time to take-off is 5.0 ms and the peak force should be 274 μN (137 μN leg–1).We predicted, from the role of octopamine in enhancing muscle tension in several locust muscles, that if stored elastic energy plays no part in force development, then genetic manipulation of the octopaminergic system would directly affect force production and jumping in Drosophila. Using two mutants deficient in the octopaminergic system, TbhnM18(M18) and TyrRhono (hono), we found significantly reduced jumping distances (20.7±0.7 and 20.7±0.4 mm, respectively) and force production (52% and 55%, respectively) compared with wild type.From the reduced distance and force production in M18, a mutant deficient in octopamine synthesis, and in hono, a tyramine/octopamine receptor mutant, we conclude that in Drosophila, as in locusts,octopamine modulates escape jumping. We conclude that the fly does not need to store large quantities of elastic energy in order to make its jump because (1)the measured and calculated forces agree to within 40% and (2) the reduction in distances jumped by the mutants correlates well with their reduction in measured peak force.
Models of hydrodynamic flow in the bowhead whale filter feeding apparatus
Authors: Werth Alexander J. 
Published: August 2004

SUMMARY
Anatomical and behavioral analyses suggest that the filtration mechanism of bowhead and right whales (Balaenidae) is driven by hydrodynamic as well as ram hydraulic pressures. Complementary models were devised to investigate biomechanical aspects of water flow in the buccal cavity of the bowhead whale Balaena mysticetus during continuous filter feeding. A mathematical model was created to test and quantify water flow predictions with steady state hydromechanical equations; a physical model of the bowhead mouth(approximately 1/15 scale) was constructed to visualize flow processes. Both models rely on morphometric data obtained from whales harvested by Inupiat Eskimos for subsistence purposes along with information on foraging ecology(locomotor velocity, gape, etc.). Results indicate that unique features of balaenid oral construction and function (e.g. subrostral gap, orolabial sulcus, curvature of baleen, extensive mandibular rotation and lingual mobility) not only permit steady, unidirectional flow of water through the mouth, but also establish Bernoulli and Venturi effects during feeding. These hydrodynamic conditions allow balaenids to improve filtering efficiency and avoid creation of an anterior compressive wave (by increasing flow velocity and thereby reducing pressure) so that they may capture elusive prey even at slow swimming speeds.
Numerical study of scalar mixing in curved channels at low Reynolds numbers
Authors: Vanka S. P. , Luo G. , Winkler C. M. 
Published: August 2004

AbstractA computational study has been performed to determine the rates of mixing in a curved square duct at low Reynolds numbers of interest to microfluidic applications. Two flow streams with inlet scalar concentrations of zero and unity in the two halves of a duct perpendicular to the plane of curvature were allowed to mix by convection and diffusion. Concentration distributions and unmixedness coefficients are presented for several Reynolds and Schmidt numbers and are compared with values for a straight channel of equivalent length. It is seen that for large Schmidt number fluids, mixing is considerably enhanced at moderately low Reynolds numbers (Re ∼ 10), but is not enhanced at Reynolds numbers of the order of 0.1. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2359–2368, 2004
Effect of waveforms on morphology development in chaotic mixing of polymers
Authors: Sau Madhusudan , Jana Sadhan C. 
Published: August 2004

AbstractThe effect of waveforms of rotor motion in a chaotic mixing device on the development of morphology in the blending of polypropylene (PP) and polyamide 6 (PA6) was investigated. The rotor motion was delivered in a steady and time‐periodic manner and the mixing effectiveness was evaluated in terms of Poincaré maps and stretching distribution, the speed of conversion of PP‐phase into droplets, and droplet size distribution. The pathway of morphology development, such as deformation of the PP‐phase into lamella, fibrils, and droplets, was found not to depend on the nature of the waveform. However, the makeup of each morphological form depended strongly on the particular waveform used. The best results were obtained when the rotor motion was delivered using a sine waveform. In this case, the PP‐phase turned most rapidly into fibrils and droplets and the droplets were of more uniform size. The square waveform, although produced higher mean stretching and showed more uniform mixing in Poincaré maps, yielded large‐size droplets, purportedly through premature breakup of the fibrils in the zones of weak flow, such as in the vicinity of the stationary rotors. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2346–2358, 2004
The gene responsible for PARK6 Parkinson's disease, PINK1, does not influence common forms of parkinsonism
Authors: Healy Daniel G. , Abou‐Sleiman Patrick M. , Ahmadi Kourosh R. , Muqit Miratul M. K. , Bhatia Kailash P. , Quinn Niall P. , Lees Andrew J. , Latchmann David S. , Goldstein David B. , Wood Nicholas W. 
Published: August 2004

AbstractMutations in the PINK1 gene (PARK6), a putative serine‐threonine kinase, cause autosomal recessive Parkinson's disease. PINK1 functions as a protein kinase and confers protective effects in the mitochondria, where it is primarily located. We assessed in a population of European ancestry whether common genetic variation in this novel gene influences nonmendelian forms of Parkinson's disease. We defined the linkage disequilibrium structure of PINK1 and used this to identify a set of tagging single nucleotide polymorphisms that we estimate will efficiently represent all of the common DNA variation in the entire gene. Genotyping these tags in a set of 576 Parkinson's disease patients and 514 controls did not demonstrate a case–control partition for allele or for haplotype and thus provides evidence against the existence of a common functional variants in PINK1 that has a strong influence on PD risk. Ann Neurol 2004;56:329–335
Preparation and rheological behaviors of 6‐carboxy‐chitosan
Authors: Zhou Yongguo , Yang Yuedong , Chuo Huimin , Liu Xiaomin 
Published: August 2004

AbstractThe hydroxymethyl groups of 2‐amino‐2‐deoxy‐D‐glucose units in chitosan were selectively oxidized to carboxyl groups with NO2 gas to form 6‐carboxy‐chitosan in aqueous 0.5 mol/L acetic acid. In optimal conditions, the 52.5% hydroxymethyl groups in chitosan could be converted into carboxyl groups. When the pH value of the solution is lower than 4.0 or more than 5.4, 6‐carboxy‐chitosan has common characteristics of a polycation or polyanion electrolyte, respectively, and when the pH value of the solution is 4.0—5.4, 6‐carboxy‐chitosan has common characteristics of an amphoteric polyelectrolyte. 6‐Carboxy‐chitosan has same macromolecular backbones as chitosan, and its isoelectric point (pI) value is 4.9. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1126–1130, 2004
Diffusion behavior of reducing agents into keratin fibers using microspectrophotometry
Authors: Kuzuhara A. , Hori T. 
Published: August 2004

AbstractTo investigate the penetration of thioglycolic acid (TG), thiolactic acid (TL), and L‐cysteine (CYS), into keratin fibers, cross‐sectional samples of virgin white human hair treated with TG, TL, and CYS were prepared. A new method for analyzing the diffusion behavior of reducing agents into human hair was developed. The diffusion pattern of reducing agents into human hair, which cannot be determined by optical microscopy, can be determined by the method developed. The method involves treating virgin hair fibers with TG, TL, and CYS. After the treatment, the cross‐sectioned hair samples were dyed with methylene blue and the cross‐sectional intensity scans were measured at a wavelength of 664 nm (λmax of methylene blue) with a microspectrophotometer. The three different diffusion patterns from the three reducing agents were obtained. The penetration of TG and TL into virgin human hair clearly increased by increasing the treatment time and pH. On the other hand, the penetration of CYS was less than TG and TL (CYS could not penetrate into the cortex region of the virgin human hair). Also, the diffusion pattern of TG showed Fickian type characteristics. The apparent diffusion coefficient of TG into human hair at pH 9.0 determined from the TG concentration profile was found to be 10−9 cm2/s. On the other hand, the apparent diffusion coefficient of TG into human hair at pH 7.0 was 10−10 cm2/s, and thus, the apparent diffusion coefficient of TG depended on the pH of the TG solution. From these experiments, we have concluded that the diffusion patterns of the three reducing agents in this study depended on the electrostatic interaction between the human hair and the reducing agents. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1131–1138, 2004
Sorption, diffusion, and swelling characteristics of sodium alginate and its blend membranes with poly(vinyl alcohol) in water–acetic acid mixtures
Authors: Aminabhavi Tejraj M. , Shetty Lakshmi C. , Naidu B. Vijaya Kumar , Mallikarjuna Nadagouda N. , Hanchinal Vanajakshi M. 
Published: August 2004

AbstractSorption, diffusion, and swelling characteristics of sodium alginate and its blend membranes with poly(vinyl alcohol) were investigated for water–acetic acid mixtures by using a gravimetric method at 30, 40, and 50°C. The membranes were characterized by X‐ray diffraction and Fourier transform infrared techniques. Concentration‐independent diffusion coefficients were obtained by applying Fick's relationship before completion of equilibrium sorption. Permeation coefficients were calculated from sorption and diffusion coefficients. Concentration profiles of liquids were computed considering the sheet geometry for the membrane by solving Fick's equation under suitable boundary conditions. Arrhenius activation parameters were computed for the transport processes. Experimental results and calculated quantities were discussed to understand membrane–solvent interactions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1139–1150, 2004
Room temperature prevulcanization of natural rubber latex using xanthate
Authors: Sasidharan K. K. , Palaty Shiny , Gopalakrishnan K. S. , George K. E. , Joseph Rani 
Published: August 2004

AbstractRoom temperature prevulcanization of natural rubber latex using a combination of xanthate and a dithiocarbamate accelerator system was investigated. The mechanical properties of the room temperature prevulcanized latex compound was compared with that of a dithiocarbamate system and a commercial prevulcanized latex. Films were prepared from the room temperature prevulcanized latex, commercial prevulcanized latex, and prevulcanized latex prepared by heating latex compound at 55°C. The mechanical properties were compared. The results show that xanthate in combination with dithiocarbamate can bring about prevulcanization at room temperature. The latex film prepared from the room temperature prevulcanized latex compound gives better clarity and tensile properties than conventional and commercial samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1164–1174, 2004