bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE HARTSHILL HORSESHOE: THE TREATMENT OF CHRONIC PAIN PATIENTS WITH DISCOGENIC PAIN IN THE ABSENCE OF NEURAL COMPRESSION A PROSPECTIVE 2½- TO 3-YEAR REVIEW
Authors: Peckett W. , Hardcastle P. , Sheppherd J. , Sridhar C. 
Published: April 2003

Interbody fusion is a well-recognized technique to achieve spinal fusion. The advantage of using tricortical blocks as opposed to the dowel technique is that intervertebral disc height can be restored. Both techniques can be performed either by the anterior or posterior approach.The traditional tricortical block technique has advantages over using dowels as it is a more stable construct and can restore intervertebral disc height. However, autologous bone graft has an unpredictable behavior causing potential problems of disc space collapse, forward displacement of the graft and donor bone graft site morbidity.The Hartshill horseshoe was developed to overcome these autograft problems. It is an implant that is placed within the periphery of the intervertebral disc space where the vertebral end plate is strongest to resist compression forces. It has holes that allow screw fixation of the implant to bone to provide immediate stability and a central area for bone graft where the vertebral body is most vascular to allow incorporation of such a graft.Previous reports on the Hartshill horseshoe have used autograft (single tricortical graft). This prospective study reports the clinical and radiological results of 19 patients who underwent this procedure using xenograft 2½ to 3 years postoperative. The radiological results do not show any evidence of loosening of the screws or implant nor evidence of intervertebral disc space subsidence. It was not possible to assess the exact incidence of spinal fusion.
EFFECT OF POVIDONE-IODINE ON THE SYNOVIAL MEMBRANE OF THE KNEE JOINT IN RATS
Authors: Moon Jeong-Lim , Sihn Jang-Cheol , Moon Myung-Sang 
Published: April 2003

The effect of two different concentrations of povidone-iodine (PVI) solution, an antiseptic, on joint synovium was investigated. In Group I, 0.05 ml of 10% PVI was used, while in Group II, 0.05 ml of 2.5% of PVI was used. PVI solution was injected twice into both knee joints with one week interval. Ten rats were used as control and 70 rats as experimental. In the two experimental groups four rats were sacrificed after 6, 12, 24 hours and three day and six rats at the end of the week after the second PVI injection. Synovial reaction was assessed histologically in both groups, based on the pathological parameters. The results suggest that intra-articular injection of 10% and 2.5% PVI induces synovitis with focal ulceration which gradually subsides, and finally, the synovium becomes normal, though various degrees of subsynovial dense fibrosis complication arise.
"OSTEOPOROSIS" IN 2000 AD: QUO VADIS?
Authors: Frost Harold M. , Jee Webster S. S. 
Published: April 2003

Here, we suggest that new ideas and knowledge about "osteoporosis" reveal necessary new directions for future work. To explain, by 1999, five studies involving a total of 1827 healthy humans from two to over 80 years of age supported this proposal in the Utah paradigm of skeletal physiology: Momentary muscle strength strongly influences and may dominate control of the biologic mechanisms that determine the postnatal strength of load-bearing bones. That italicized proposal differed so much from former views that before 1999, few people thought it deserved testing in humans. The above five studies did finally test it, and they support it. If true, its implications would affect many things. In part, they include (A), genetic effects on bone strength and "mass", muscle and "osteoporosis"; (B) the pathogenesis, diagnosis, classification, prevention and management of "osteoporosis"; (C) the things osteoporosis-oriented basic, clinical and pharmaceutical research should study; (D) the absorptiometric methods and animal models used to study the disorder; (E) which research projects would receive preferred funding; (F) and the content of future texts, review articles, classroom lectures and many osteoporosis-oriented meetings. Many might find some of those implications dubious. While we will respect such doubts, this article describes some of those implications so others can exploit them and/or help to resolve any disagreements they may cause. Because they depend on the Utah paradigm of skeletal physiology, some of its pertinent features must be summarized.
THE EFFECT OF GRADUAL PASSIVE STATIC POSTERIOR COMPRESSION WITH HOOKED RODS ON THE SPINE OF GROWING DOGS
Authors: Moon Myung-Sang , Lee Young-Soo 
Published: April 2003

Spinal instrumentations have been practiced frequently for surgical stabilization of unstable segment, correction of the various deformities and maintenance of the correction. We performed this study to assess the effect of passive posterior static compression immobilization with hooked rods on the growth of spines of immature dogs. The immobilized bony vertebrae grew less than the nonimmobilized vertebrae above and below, and narrowing of the intervertebral disc spaces in the immobilized segments occurred in all dogs. The A–P diameter of the spinal canal in the immobilized segments increased up to 14% in comparison with the mobilized vertebrae above and below. Degenerative changes and narrowing of the facet joints developed gradually. From postop 16 weeks onwards, degeneration of the growth plate cartilage of compressed vertebrae developed. These areas of degeneration were sharply demarcated from the remaining normal cartilage layer of the growth plate. The direction of horizontally arranged fibers of annulus fibrosus began to distort and all the fibers of the annulus were vertically arranged completely at the end. The endplate cartilage gradually became thinner, and lastly, the profound degeneration occurred. Through this study, it was found that growth of the vertebral height, particularly in the posterior part, was suppressed by the growth retardation of the growth plate. The lordosis of the immobilized vertebral segments was caused mostly by disc changes and partly by the corporal growth suppression. It was also found that prolonged posterior instrumented immobilization and compression of the spine ultimately resulted in arthrosis, and that the unequal posterior axial compression of immature spine with static compression rod or rods could induce lordoscoliosis. In summary, this study clearly demonstrated that instrumented posterior static compression of the growing spine by hooked rods suppressed the posterior spinal growth, while there was less growth suppression on the vertebral body anteriorly. In conclusion, this study provided plausible explanation for the development of the crankshaft phenomenon after posterior static-instrumented compressive stabilization of immature animals with hooked rods.
THE UTILITY OF DIAGNOSING LUMBAR ROTATIONAL INSTABILITY FROM TWIST CT SCANS
Authors: Singer K. P. , Svansson G. , Day R. E. , Breidahl W. H. , Horrex A. 
Published: April 2003

The twist CT has been advocated as a useful diagnostic tool for determining lumbar segment instability. According to this test, facet joints showing wide separation on lumbar spine rotation are believed to be pathological. However, no reports have presented the reliability of measuring facet joint separation from clinical twist CT films, nor tested for an association between tendency to separate and anatomical joint orientation. Forty-five patients, referred for mechanical low back pain, were scanned first in neutral, then right and left trunk twisted positions. Images were video-digitized onto computer for quantitative measurement of facet joint morphology. The induced facet joint separation was contrasted with the neutral scan joint approximation and any difference was expressed in millimeters. The coefficient of variability (c.v.) of defining right and left transverse plane facet joint orien-tation, and of joint separation, from repeated assessment in ten images was acceptable (c.v. = 2% and 3.5%, respectively). The average joint angle increased from L2–3 to L5–S1 and the mean facet joint separation of 2.6 mm was greatest at the L4–5 level. Forty-three percent of all segments showed little additional separation (<0.2 mm ) when in a rotated posture. In the remainder, a slight relationship existed between facet geometry and separation; joints with wider angles were associated with greater separation than those with a more sagittal configuration (r=0.36, p<0.01). No conclusive trend was recorded in this patient series for facet joints to separate when the subject adopted an end-range rotated posture. A mild association between physiological separation of facet joints and their morphological angle was determined. This trend alone should not afford confidence in attributing such separation as having pathological significance.
EFFECTS OF FLUORIDE ON GROWTH PLATE AND BONE HISTOPATHOLOGY IN YOUNG RATS
Authors: Heybeli Nurettin , Eroğlu Erol , Sari Aliye , Çetin Meltem , Mumcu Ethem Faruk 
Published: April 2003

The purpose of this study is to investigate the effects of normal, moderate and high doses of fluoride on rat epipyseal growth plate and surrounding bone, and to compare it with controls. In order to achieve this, 80 rats were divided into five groups (n: 16/group) and treated with 0, 1.2, 3, 50 and 100 ppm fluoridated water since birth (Groups I to V, respectively). Four rats from each group were sacrificed at 6th, 9th, 12th and 16th weeks for radiological and histopathological examinations.There was no significant variation on programmed cell death of cartilagenous components of the growth plate and chondroid matrix histopathologically between control group and fluoride-treated groups. But, minimal irregularities on the cartilage septum of primary spongiosa were detected in one rat from Group IV and one from Group V. The main histopathologic findings of the rats which were treated with high doses of fluoride were irregular lamella, variation in calcium content, minimally enlarged Haversian canals, focal osteoblastic proliferation, rare zones of woven bone on the diaphyseal cortical bone and secondary spongiosa, increase in ossicle size and minimal focal osteoblastic proliferation on the secondary ossification center. The only consistent radiological finding was relative widening and late partial fusing of the epiphyseal growth plates of high-dose treated groups at 16th week.As a result, high doses of fluoride did not directly affect chondrocyte morphology of growth plate on young rats. More sophisticated techniques would be beneficial for further investigations on this subject.
CLOSED-LOOP CONTROL OF QUADRICEPS/HAMSTRING ACTIVATION FOR FES-INDUCED STANDING-UP MOVEMENT OF PARAPLEGICS
Authors: Yu Nan-Ying , Chen Jia-Jin Jason , Ju Ming Shiang 
Published: April 2003

Functional electrical stimulation (FES) standing system can enable the paraplegics to achieve the standing position for functional activities in daily living. FES standing system is usually applied by stimulating the knee extensor muscles. The hip joints are in hyperextension and the ankle joints remain free. Therefore, the knee joint control is the key point of the FES standing control system. Traditional open-loop control often induces high knee end-velocity (KEV) when the subject reaches the upright position. In this work, the reducing of KEV by closed-loop control was addressed. An on/off feedback control based on mechanical energy conservation was developed to control the knee extensors and flexors. The result was compared to the open loop controlled standing up in a mechanically simulative experiment. It is concluded that the on/off control strategy can reduce the KEV more efficiently when compared to the open-loop control. Proportional-integral-derivative (PID) position controlled standing up was also studied and compared with the on/off control system. The PID controller was found to be capable of reducing KEV to a level lower than that of the on/off control, whereas its instability for knee control was also found.
IMPLIED AND LOCAL VOLATILITIES UNDER STOCHASTIC VOLATILITY
Authors: LEE ROGER W. 
Published: April 2003

For asset prices that follow stochastic-volatility diffusions, we use asymptotic methods to investigate the behavior of the local volatilities and Black–Scholes volatilities implied by option prices, and to relate this behavior to the parameters of the stochastic volatility process. We also give applications, including risk-premium-based explanations of the biases in some naïve pricing and hedging schemes. We begin by reviewing option pricing under stochastic volatility and representing option prices and local volatilities in terms of expectations. In the case that fluctuations in price and volatility have zero correlation, the expectations formula shows that local volatility (like implied volatility) as a function of log-moneyness has the shape of a symmetric smile. In the case of non-zero correlation, we extend Sircar and Papanicolaou's asymptotic expansion of implied volatilities under slowly-varying stochastic volatility. An asymptotic expansion of local volatilities then verifies the rule of thumb that local volatility has the shape of a skew with roughly twice the slope of the implied volatility skew. Also we compare the slow-variation asymptotics against what we call small-variation asymptotics, and against Fouque, Papanicolaou, and Sircar's rapid-variation asymptotics. We apply the slow-variation asymptotics to approximate the biases of two naïve pricing strategies. These approximations shed some light on the signs and the relative magnitudes of the biases empirically observed in out-of-sample pricing tests of implied-volatility and local-volatility schemes. Similarly, we examine the biases of three different strategies for hedging under stochastic volatility, and we propose ways to implement these strategies without having to specify or estimate any particular stochastic volatility model. Our approximations suggest that a number of the empirical pricing and hedging biases may be explained by a positive premium for the portion of volatility risk that is uncorrelated with asset risk.
OPERATORS ON INHOMOGENEOUS TIME SERIES
Authors: ZUMBACH GILLES , MÜLLER ULRICH 
Published: April 2003

We present a toolbox to compute and extract information from inhomogeneous (i.e. unequally spaced) time series. The toolbox contains a large set of operators, mapping from the space of inhomogeneous time series to itself. These operators are computationally efficient (time and memory-wise) and suitable for stochastic processes. This makes them attractive for processing high-frequency data in finance and other fields. Using a basic set of operators, we easily construct more powerful combined operators which cover a wide set of typical applications. The operators are classified as either macroscopic operators (that have a limit value when the sampling frequency goes to infinity) or microscopic operators (that strongly depend on the actual sampling). For inhomogeneous data, macroscopic operators are more robust and more important. Examples of macroscopic operators are (exponential) moving averages, differentials, derivatives, moving volatilities, etc.…
DESIGN AND VALUATION OF CORPORATE SECURITIES WITH STRATEGIC DEBT SERVICE AND ASYMMETRIC INFORMATION
Authors: PAN YONGHUA 
Published: April 2003

This paper studies the effects of strategic debt service, asymmetric information and their interaction on the valuation of corporate securities and on corporate financing decisions. By introducing information asymmetry into a continuous-time setting, our model is able to integrate these two factors in a unified framework. Such a model allows for obtaining valuation results in a separating equilibrium. The basic results of this paper imply that the risk premium of debt could be partly contributed by information effect. This part of risk premium could be very significant for those good firms with a project which will produce much higher cash flows than what the market expects. We also find that a firm's financing decision depends on its primitives: firms are more apt to rely on equity if they have: (1) high growth potential, (2) riskier projects, (3) higher ratio of intangible assets to total assets and (4) lesser information asymmetry; firms would prefer debt, otherwise.
ONE- AND MULTI-FACTOR VALUATION OF MORTGAGES: COMPUTATIONAL PROBLEMS AND SHORTCUTS
Authors: LEVIN ALEXANDER 
Published: April 2003

A new valuation method is proposed that can be mathematically viewed as a numerical shortcut to approximately solve the partial differential equation written for Expected Instantaneous Return. The method derives OAS as "static spread plus cost of convexity" and is based on some simplified parametric assumption about the static spread's time behavior. The modeling and numerical procedure details are disclaimed with proven accuracy and time efficiency in option-adjusted valuation. The method is especially effective for multi-scenario pricing, portfolio pricing, risk management and reporting, and for quantifying the impact of "non-traded" factors on reward and risk of holding mortgages. A systematic methodology for comprehensive multi-factor analysis is covered.
TENSOR PRODUCT SYSTEMS OF HILBERT MODULES AND DILATIONS OF COMPLETELY POSITIVE SEMIGROUPS
Authors: BHAT B. V. RAJARAMA , SKEIDE MICHAEL 
Published: April 2003

In this paper we study the problem of dilating unital completely positive (CP) semigroups (quantum dynamical semigroups) to weak Markov flows and then to semigroups of endomorphisms (E0-semigroups) using the language of Hilbert modules. This is a very effective, representation free approach to dilation. In this way we are able to identify the right algebra (maximal in some sense) for endomorphisms to act. We are led inevitably to the notion of tensor product systems of Hilbert modules and units for them, generalizing Arveson's notions for Hilbert spaces. In the course of our investigations we are not only able to give new natural and transparent proofs of well-known facts for semigroups on [Formula: see text], but also extend the results immediately to much more general setups. For instance, Arveson classifies E0-semigroups on [Formula: see text] up to cocycle conjugacy by product systems of Hilbert spaces.5 We find that conservative CP-semigroups on arbitrary unital C*-algebras are classified up to cocycle conjugacy by product systems of Hilbert modules. Looking at other generalizations, it turns out that the role played by E0-semigroups on [Formula: see text] in dilation theory for CP-semigroups on [Formula: see text] is now played by E0-semigroups on [Formula: see text], the full algebra of adjointable operators on a Hilbert module E. We have CP-semigroup versions of many results proved by Paschke27 for CP maps.
ON THE COMBINATORIAL STRUCTURE OF PRIMITIVE VASSILIEV INVARIANTS, III — A LOWER BOUND
Authors: DASBACH OLIVER T. 
Published: April 2003

We prove that the dimension of the space of primitive Vassiliev invariants of degree n grows — as n tends to infinity — faster than [Formula: see text] for any [Formula: see text]. This solves the so-called Kontsevich–Bar–Natan conjecture. The proof relies on the use of the weight systems coming from the Lie algebra [Formula: see text] (N). In fact, we show that our bound is — up to a multiplication by a rational function in n — the best possible that one can get with [Formula: see text](N)-weight systems.
CHEEGER ISOPERIMETRIC CONSTANTS OF GROMOV-HYPERBOLIC SPACES WITH QUASI-POLES
Authors: CAO JIANGUO 
Published: April 2003

Let X be a non-compact complete manifold (or a graph) which admits a quasi-pole and has bounded local geometry. Suppose that X is Gromov-hyperbolic and the diameters (for a fixed Gromov metric) of the connected components of X(∞) have a positive lower bound. Under these assumptions we show that X has positive Cheeger isoperimetric constant. Examples are also constructed to show that the Cheeger constant h(X) may be zero if any of the above assumption on X is removed. Applications of this isoperimetric estimate include the solvability of the Dirichlet problem at infinity for non-compact Gromov-hyperbolic manifolds X above. In addition, we show that the Martin boundary ∂ΔX of such a space X is homeomorphic to the geometric boundary X(∞) of X at infinity.
BROADCASTING IN BUS INTERCONNECTION NETWORKS
Authors: FERREIRA A. , GOLDMAN A. , SONG S. W. 
Published: April 2003

In most distributed memory MIMD multiprocessors, processors are connected by a point-to-point interconnection network, usually modeled by a graph where processors are nodes and communication links are edges. Since interprocessor communication frequently constitutes serious bottlenecks, several architectures were proposed that enhance point-to-point topologies with the help of multiple bus systems so as to improve the communication efficiency. In this paper we study parallel architectures where the communication means are constituted solely by buses. These architectures can use the power of bus technologies, providing a way to interconnect much more processors in a simple and efficient manner. We present the hyperpath, hypergrid, hyperring, and hypertorus architectures, which are the bus-based versions of the well used point-to-point interconnection networks. Using (hyper) graph theoretic concepts to model inter-processor communication in such networks, we give optimal algorithms for broadcasting a message from one processor to all the others. For deriving high performance communication patterns we developed a new tool called simplification. The idea is to construct a graph, to be called representative graph, from the original hyper-topology, in such a way that it will become easy to describe and perform communication schemes to the former that will fit to the latter, because the simplification concept also allows us to partially use some already known communication algorithms for usual networks.
STATIC AND DYNAMIC EVALUATION OF QoS PROPERTIES
Authors: PANDURANGAN GOPAL , UPFAL ELI 
Published: April 2003

Efficient utilization of modern high bandwidth communication networks relies on statistical multiplexing of many logical channels through one physical channel. Communication requests typically include some statistical characterization of the requested connection (such as pick value, mean values, etc). The task of the network management procedure is to accommodate as many communication requests as possible while keeping the failure (e.g. overflow) probability bounded by a pre-specified parameter. When the network consists of one link, the task reduces to evaluating the probability that a sum of random variables does not exceed a given bound. Techniques such as the method of effective bandwidth give a practical solution for the one link problem. In this paper we address the more realistic setting of estimating QoS properties of multi-link networks with arbitrary patterns. The related optimization problem for that setting is #P-complete even for the most simple communication characteristics. Our main result is an efficient Monte-Carlo method for estimating the failure probability of a general network. Our method is particularly useful in a dynamic setting in which communication requests are dynamically added and eliminated from the system. The amortized cost in our solution of updating the estimate after each change is proportional to the fraction of links involved in the change rather than to the total number of links in the network.