bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coverage of Painful Peripheral Nerve Neuromas with Vascularized Soft Tissue: Method and Results
Authors: Krishnan Kartik G. , Pinzer Thomas , Schackert Gabriele 
Published: April 2005

AbstractOBJECTIVE:Our goals are to describe a method of treating painful peripheral nerve neuromas by means of vascularized tissue coverage, report the results in seven patients, and discuss the indications for this treatment modality. An analysis of pain, functionality of the affected body part, professional activities of the patients, and medications before and after surgery is presented.METHODS:Seven male patients (mean age, 45.1 yr) with posttraumatic nerve injuries, who had developed painful stump neuromas or neuromas-in-continuity, and who had unsuccessfully undergone several treatment procedures, were selected for the surgery described here. The operation included resection of the stump neuroma (four patients) or neurolysis of the neuroma-in-continuity (three patients) and coverage of the nerve with a vascularized fascial, fasciocutaneous, or perforator flap (three pedicled regional flaps and four free flaps). A modified quadruple visual analog scale was used to quantify pain before and after surgical treatment. The mean follow-up was 16.6 months.RESULTS:The mean values of the quadruple visual analog scale (pain now/typically/at its best/at its worst) before surgery were 6.5/6.5/4.7/7.9. These values changed to 0.3/0.4/0/0.9 at a mean follow-up of 16.6 months after surgery. Five patients returned to their original profession, one receives a pension, and one began a less demanding job after undergoing surgery. Six of the seven patients received opioids before surgery (one had a spinal cord stimulator). After surgery, all patients stopped taking regular pain killers and the spinal cord stimulator was deactivated in one; two patients still take nonsteroidal anti-inflammatory drugs occasionally, but not on a regular basis.CONCLUSION:Vascularized soft tissue coverage of painful peripheral nerve neuromas seems to be an effective and attractive, but also complex, method of treatment. This option may be considered and reserved for patients who have already undergone several pain treatment modalities without success.
Temporary Aneurysm Orifice Balloon Occlusion as an Alternative to Retrograde Suction Decompression for Giant Paraclinoid Internal Carotid Artery Aneurysms: Technical Note
Authors: Steiger Hans-Jakob , Lins Farias , Mayer Thomas , Schmid-Elsaesser Robert , Stummer Walter , Turowski Bernd 
Published: April 2005

Abstract

OBJECTIVE:
Giant paraclinoid carotid artery aneurysms frequently require the temporary interruption of local circulation to facilitate safe clip occlusion. Owing to the brisk retrograde blood flow through the ophthalmic artery and cavernous branches, the simple trapping of the aneurysm by cervical internal carotid artery clamping and intracranial distal clipping may not adequately soften the lesion. Retrograde suction decompression aspiration of this collateral supply by a catheter introduced into the cervical internal carotid artery is a popular method to achieve aneurysm deflation. With a large collateral supply, the method is not effective enough. The advent of relatively long and maneuverable soft balloons allows temporary occlusion of the aneurysm orifice.

METHODS:
We applied this method in two instances of giant carotid ophthalmic aneurysms. In both instances, a 15- to 20-mm-long and 4-mm-wide occlusion balloon was inserted in the internal carotid artery at the level of the aneurysm before craniotomy. After craniotomy and dissection of the aneurysm neck, the balloon was inflated under intraoperative angiographic control.

RESULTS:
The aneurysm became soft enough in both cases without tapping and aspiration to allow safe clip occlusion. In the first case, the postoperative course was uneventful and visual acuity improved. A known additional infraclinoid part of the aneurysm was eliminated endovascularly 5 months later using balloon-protected injection of vinyl alcohol copolymer (Onyx; Micro Therapeutics, Inc., Irvine, CA). In the second case, a postoperative symptomatic vasospasm developed 15 hours after surgery. Hypertensive therapy resulted in the disappearance of symptoms and an otherwise uneventful course with improvement of vision.

CONCLUSION:
This preliminary experience suggests that this new method is a feasible alternative to retrograde suction decompression.
Membranes and the setting of energy demand
Authors: Hulbert A. J. , Else P. L. 
Published: April 2005

SUMMARYIn his classic 1961 book, The Fire of Life, Max Kleiber presented a critique of the theories advanced to explain the BMR-body size relationship. One of the theories he dismissed was that the chemical composition of animals varies with body size. Since this time, however, much has been learned about the make-up of BMR in different animals as well as the chemical composition of different-sized animals. Specifically, in recent years it has become obvious that mammal species and bird species do vary in chemical composition in a systematic manner associated with the body size of the species. Small mammal and bird species have cellular membranes that are predominantly polyunsaturated, and as mammal and bird species increase in size, their cellular membranes become progressively less polyunsaturated. Since Kleiber's time, it has also become obvious that a substantial amount of the energy turnover of BMR is associated with the activity of membrane processes,specifically the maintenance of trans-membrane gradients, such as the Na+ gradient across the plasmalemmal membrane and the H+gradient across the mitochondrial inner membrane. The variation in both membrane composition and membrane processes associated with body size variation in metabolic rate has been combined in the `membrane pacemaker'theory of metabolism. This theory proposes that: (1) membrane-associated activities are significant and dominant components of BMR; (2) when BMR varies among species, all the activities that constitute BMR vary in unison; (3)species with high mass-specific BMR have highly polyunsaturated membranes while those with low BMR have less polyunsaturation of their membranes; (4)highly polyunsaturated membranes have distinctive physical properties that cause the proteins in the membranes to have a high molecular activity, and this results in higher rates of metabolism of cells, tissues and,consequently, the whole animal. Evidence supporting this theory is both correlative and experimental. Manipulation of membrane composition changes the molecular activity of membrane proteins. These differences in membrane composition may also represent a link between metabolism and aging. They probably explain the lifespan-body size relationship in mammals and birds and also the mammal-bird difference in lifespan.
Biomechanical consequences of scaling
Authors: Biewener Andrew A. 
Published: April 2005

SUMMARYTo function over a lifetime of use, materials and structures must be designed to have sufficient factors of safety to avoid failure. Vertebrates are generally built from materials having similar properties. Safety factors are most commonly calculated based on the ratio of a structure's failure stress to its peak operating stress. However, yield stress is a more likely limit, and work of fracture relative to energy absorption is likely the most relevant measure of a structure's safety factor, particularly under impact loading conditions characteristic of locomotion. Yet, it is also the most difficult to obtain. For repeated loading, fatigue damage and eventual failure may be critical to the design of biological structures and will result in lower safety factors. Although area:volume scaling predicts that stresses will increase with size, interspecific comparisons of mammals and birds show that skeletal allometry is modest, with most groups scaling(l∝d0.89) closer to geometric similarity(isometry: l ∝d1.0) than to elastic similarity (l ∝d0.67) or stress similarity(l ∝d0.5). To maintain similar peak bone and muscle stresses, terrestrial mammals change posture when running, with larger mammals becoming more erect. More erect limbs increases their limb muscle mechanical advantage (EMA) or ratio of ground impulse to muscle impulse(r/R=∫G/∫Fm). The increase in limb EMA with body weight (∝W0.25) allows larger mammals to match changes in bone and muscle area (∝W0.72-0.80) to changes in muscle force generating requirements (∝W0.75), keeping bone and muscle stresses fairly constant across a size range 0.04-300 kg. Above this size, extremely large mammals exhibit more pronounced skeletal allometry and reduced locomotor ability. Patterns of ontogenetic scaling during skeletal growth need not follow broader interspecific scaling patterns. Instead,negative allometric growth (becoming more slender) is often observed and may relate to maturation of the skeleton's properties or the need for younger animals to move at faster speeds compared with adults. In contrast to bone and muscle stress patterns, selection for uniform safety factors in tendons does not appear to occur. In addition to providing elastic energy savings, tendons transmit force for control of motion of more distal limb segments. Their role in elastic savings requires that some tendons operate at high stresses (and strains), which compromises their safety factor. Other `low stress' tendons have larger safety factors, indicating that their primary design is for stiffness to reduce the amount of stretch that their muscles must overcome when contracting to control movement.
Exercise-induced maximal metabolic rate scales with muscle aerobic capacity
Authors: Weibel Ewald R. , Hoppeler Hans 
Published: April 2005

SUMMARYThe logarithmic nature of the allometric equation suggests that metabolic rate scaling is related to some fractal properties of the organism. Two universal models have been proposed, based on (1) the fractal design of the vasculature and (2) the fractal nature of the `total effective surface' of mitochondria and capillaries. According to these models, basal and maximal metabolic rates must scale as M3/4. This is not what we find. In 34 eutherian mammalian species (body mass Mbranging from 7 g to 500 kg) we found V̇O2max to scale with the 0.872 (±0.029) power of body mass, which is significantly different from 3/4 power scaling. Integrated structure-function studies on a subset of eleven species (Mb 20 g to 450 kg) show that the variation of V̇O2max with body size is tightly associated with the total volume of mitochondria and of the locomotor musculature capillaries. In athletic species the higher V̇O2max is linked to proportionally larger mitochondrial and capillary volumes. As a result, V̇O2max is linearly related to both total mitochondrial and capillary erythrocyte volumes, as well as to their surface areas. Consequently, the allometric variation of maximal metabolic rate is directly related to the scaling of the total effective surfaces of mitochondria and capillaries, thus confirming the basic conjecture of the second fractal models but refuting the arguments for 3/4 power scaling. We conclude that the scaling of maximal metabolic rate is determined by the energy needs of the cells active during maximal work. The vascular supply network is adapted to the needs of the cells at their working limit. We conjecture that the optimization of the arterial tree by fractal design is the result rather than the cause of the evolution of metabolic rate scaling. The remaining question is why the energy needs of locomotion scale with the 0.872 or 7/8 power of body mass.
Problems of allometric scaling analysis: examples from mammalian reproductive biology
Authors: Martin Robert D. , Genoud Michel , Hemelrijk Charlotte K. 
Published: April 2005

SUMMARYBiological scaling analyses employing the widely used bivariate allometric model are beset by at least four interacting problems: (1) choice of an appropriate best-fit line with due attention to the influence of outliers; (2)objective recognition of divergent subsets in the data (allometric grades);(3) potential restrictions on statistical independence resulting from phylogenetic inertia; and (4) the need for extreme caution in inferring causation from correlation. A new non-parametric line-fitting technique has been developed that eliminates requirements for normality of distribution,greatly reduces the influence of outliers and permits objective recognition of grade shifts in substantial datasets. This technique is applied in scaling analyses of mammalian gestation periods and of neonatal body mass in primates. These analyses feed into a re-examination, conducted with partial correlation analysis, of the maternal energy hypothesis relating to mammalian brain evolution, which suggests links between body size and brain size in neonates and adults, gestation period and basal metabolic rate. Much has been made of the potential problem of phylogenetic inertia as a confounding factor in scaling analyses. However, this problem may be less severe than suspected earlier because nested analyses of variance conducted on residual variation(rather than on raw values) reveals that there is considerable variance at low taxonomic levels. In fact, limited divergence in body size between closely related species is one of the prime examples of phylogenetic inertia. One common approach to eliminating perceived problems of phylogenetic inertia in allometric analyses has been calculation of `independent contrast values'. It is demonstrated that the reasoning behind this approach is flawed in several ways. Calculation of contrast values for closely related species of similar body size is, in fact, highly questionable, particularly when there are major deviations from the best-fit line for the scaling relationship under scrutiny.
Model-matching control applied to longitudinal and lateral automated driving
Authors: Kwon Seong-Jin , Fujioka Takehiko , Cho Ki-Yong , Suh Myung-Won 
Published: April 2005

Although there has been substantial research on longitudinal and lateral controllers for an automated driving system, stability issues with respect to the effect of uncertainties due to parameter variations (e.g. in the vehicle mass and the cornering stiffness) and disturbances or perturbations to the vehicle system (e.g. in the road gradient and the wind) still need to be addressed. Thus, an automated driving system needs to be made robust to those influences.For this purpose, the model-matching control applied to longitudinal and lateral automated driving is investigated by vehicle dynamics simulation. The design of the model-matching controller is obtained by using the characteristics of a two-degree-of-freedom controller. It can make various characteristics of automated driving vehicles equivalent to a specific transfer function, which is suggested as the reference model.The vehicle dynamics models including the model-matching controller are constructed for computer simulation. Then, simple examples of open-loop simulation and closed-loop simulation are solved to check the robustness of the model-matching controller. As a practical example, an automated driving system is adopted. It is proved that the model-matching control is effective and adequate for uncertainties due to parameter variation and disturbances or perturbations to the vehicle system, which are shown in the responses of the changes in the vehicle mass, the road gradient and the cornering stiffness.
Vibration analysis of a vehicle system supported on a damper-controlled variable-spring-stiffness suspension
Authors: Ghosh M K , Dinavahi R 
Published: April 2005

Vibration isolation performance has been investigated for a vehicle system supported on a damper-controlled variable-spring-stiffness suspension system. A half-car model has been analysed for different values of damping ratio, relative damping ratio, and mass ratio. The semi-active control of a half-car model has been investigated with the help of a force generator as well as with optimal control theory. The results show that a damper-controlled variable-stiffness suspension improves the vibration isolation performance of the suspension system. It has been found that a lower damping ratio, a relative damping ratio of unity, and a higher mass ratio gives optimum reduction in the transmissibility of motion from road surface to the vehicle body. The semi-active control of a half-car model supported on a damper-controlled variable-springstffiness suspension can be achieved using a force generator or an actuator. The use of a force generator can minimize the power required to control the damper. A full-state feedback and linear quadratic regulator control theory gives better results for higher mass ratios.
Experimental investigations of the effect of biodiesel utilization on lubricating oil tribology in diesel engines
Authors: Agarwal A K 
Published: April 2005

Biodiesel is an alternative fuel derived from vegetable oils by modifying their molecular structure through a transesterification process. Linseed oil methyl ester (LOME) was prepared using methanol in the presence of potassium hydroxide as a catalyst. The use of LOME in compression ignition engines was found to develop a very compatible engine-fuel system with lower emission characteristics. Two identical engines were subjected to long-term endurance tests, fuelled by an optimum biodiesel blend (20 per cent LOME) and diesel oil, respectively. Various tribological studies on lubricating oil samples drawn at regular intervals from both engines were conducted in order to correlate the comparative performance of the two fuels and the effect of fuel chemistry on lubricating oil performance and life. A number of tests were conducted in order to evaluate the comparative performances of the two fuels such as density measurement, viscosity measurements, Flashpoint determination, moisture content determination, pentane and benzene insolubles, thin layer chromatography, differential scanning calorimetry, etc. All these tests were used for an indirect interpretation of the comparative performance of these fuels. The performance of biodiesel fuel is found to be superior to that of diesel oil and the lubricating oil life is found to be longer while operating the engine on biodiesel
Neuroeconomics: How Neuroscience Can Inform Economics
Authors: Camerer Colin , Loewenstein George , Prelec Drazen 
Published: April 2005

Neuroeconomics uses knowledge about brain mechanisms to inform economic analysis, and roots economics in biology. It opens up the “black box” of the brain, much as organizational economics adds detail to the theory of the firm. Neuroscientists use many tools— including brain imaging, behavior of patients with localized brain lesions, animal behavior, and recording single neuron activity. The key insight for economics is that the brain is composed of multiple systems which interact. Controlled systems (“executive function”) interrupt automatic ones. Emotions and cognition both guide decisions. Just as prices and allocations emerge from the interaction of two processes—supply and demand— individual decisions can be modeled as the result of two (or more) processes interacting. Indeed, “dual-process” models of this sort are better rooted in neuroscientific fact, and more empirically accurate, than single-process models (such as utility-maximization). We discuss how brain evidence complicates standard assumptions about basic preference, to include homeostasis and other kinds of state-dependence. We also discuss applications to intertemporal choice, risk and decision making, and game theory. Intertemporal choice appears to be domain-specific and heavily influenced by emotion. The simplified ß-d of quasi-hyperbolic discounting is supported by activation in distinct regions of limbic and cortical systems. In risky decision, imaging data tentatively support the idea that gains and losses are coded separately, and that ambiguity is distinct from risk, because it activates fear and discomfort regions. (Ironically, lesion patients who do not receive fear signals in prefrontal cortex are “rationally” neutral toward ambiguity.) Game theory studies show the effect of brain regions implicated in “theory of mind”, correlates of strategic skill, and effects of hormones and other biological variables. Finally, economics can contribute to neuroscience because simple rational-choice models are useful for understanding highly-evolved behavior like motor actions that earn rewards, and Bayesian integration of sensorimotor information. Who knows what I want to do? Who knows what anyone wants to do? How can you be sure about something like that? Isn't it all a question of brain chemistry, signals going back and forth, electrical energy in the cortex? How do you know whether something is really what you want to do or just some kind of nerve impulse in the brain. Some minor little activity takes place somewhere in this unimportant place in one of the brain hemispheres and suddenly I want to go to Montana or I don't want to go to Montana. (White Noise, Don DeLillo)
The new GMS contract: impact and implications for managing the changes
Authors: Spurgeon Peter , Hicks Carolyn , Field Stephen , Barwell Fred 
Published: April 2005

Background: In February 2003, a new General Practitioner (GP) contract was agreed between the profession's leaders and the government, which was later accepted following a national ballot of GPs. However, the ballot simply required respondents to vote for or against the proposal; it did not provide any opportunity to identify which aspects of the new contract were more or less acceptable. Since the proposed changes were far reaching, the implications of implementing and managing these were considerable. Consequently, some information about how GPs viewed various components of the new contract would enable a more targeted and effective management strategy to be developed that would facilitate the introduction of all aspects of the contract. Objectives: To survey GPs working within the West Midlands region regarding their opinions on each of the key features of the new contract. Method: A postal survey of 360 GPs was undertaken, using a specially devised questionnaire. Results: Four factors emerged as the most acceptable aspects of the contract: option to opt out of out-of-hours work, flexibility in the services provided, prediction of future income levels and linking practice to performance targets. Least acceptable were: performance monitoring systems, the new financial formula for calculating income, greater patient involvement in service development and 24/48 hour access. With regard to potential outcomes of the contract, the most positive were considered to be increased proportion of salaried GPs, increased salaries, appropriate quality standards for care, earlier retirement; the factors least likely to be of potential benefit were: reduction in occupational stress, simplification of the regulatory framework, improved equity of workload and improved staff retention. Further analysis of the results using inferential statistics revealed a range of subgroup differences in reaction to the contract. Conclusion: Overall, those aspects of the new contract that are perceived to reduce workload and enhance salary were supported, while those that increase targets and bureaucracy were not. Generally, there was only moderate support for the changes, which could be explained by a general scepticism about any top-down modifications, the practicality and power of the changes to impact upon practice and/or a genuine belief that the modifications are unacceptable. Taken together, these results provide an indicative focus for managing the implementation of the new contract, especially with regard to its least acceptable components and the emerging differences between subgroups of GPs.