bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endonasal Transsphenoidal Transclival Removal of Prepontine Epidermoid Tumors: Technical Note
Authors: Esposito Felice , Becker Donald P. , Villablanca Juan Pablo , Kelly Daniel F. 
Published: April 2005

Abstract

OBJECTIVE:
Prepontine retroclival tumors have typically been removed through a variety of anterolateral, lateral, and posterolateral cranial base approaches. Here, we describe an endonasal transclival cranial base approach for removal of prepontine epidermoid tumors.

METHODS:
Two men, 40 and 52 years old, each presented with a history of headaches and cranial nerve deficits. In each patient, magnetic resonance imaging showed a large T1 hypointense/T2 hyperintense mass occupying the posterior suprasellar, premesencephalic, and prepontine cisterns, with significant mass effect on the brainstem. Both patients underwent an endonasal transsphenoidal transclival cranial base tumor removal with the operating microscope and endoscopic assistance. The dural and bony defects were repaired with abdominal fat grafts, collagen sponge, titanium mesh, and cerebrospinal fluid diversion. One patient developed a postoperative cerebrospinal fluid leak and meningitis requiring two reoperations to repair, ultimately with fat and fascia lata grafts.

RESULTS:
At 1 year after surgery, both patients have improved compared with their preoperative neurological state, and volume analysis of preoperative and 1-year postoperative magnetic resonance imaging scans confirm a marked reduction in mass effect on the brainstem, with a 78% tumor removal in one patient and 76% removal in the other. Both patients have normal endocrine function.

CONCLUSION:
The endonasal approach offers a minimally invasive, anatomically direct route for removing prepontine epidermoid tumors that obviates brain retraction. The use of angled endoscopes is essential for gaining lateral, cephalad, and caudal visualization to augment the limited microscope view. Inadequate repair of clival dural defects remains the greatest potential pitfall in attempting transsphenoidal transclival tumor removal.
Frontobasal Interhemispheric Trans-Lamina Terminalis Approach for Suprasellar Lesions
Authors: Dehdashti Amir R. , de Tribolet Nicolas 
Published: April 2005

Abstract
THE FRONTOBASAL INTERHEMISPHERIC APPROACH for suprasellar tumors currently incorporates technological advancements and refinements in patient selection, operative technique, and postoperative care. This technique is a valid choice for the removal of suprasellar lesions with extension into the third ventricle without major sequelae related to the surgical approach. The method described here reflects the combination of the frontal interhemispheric and trans-lamina terminalis approaches.
The constructal law of organization in nature: tree-shaped flows and body size
Authors: Bejan Adrian 
Published: April 2005

SUMMARY
The constructal law is the statement that for a flow system to persist in time it must evolve in such a way that it provides easier access to its currents. This is the law of configuration generation, or the law of design. The theoretical developments reviewed in this article show that this law accounts for (i) architectures that maximize flow access (e.g. trees), (ii)features that impede flow (e.g. impermeable walls, insulation) and (iii)static organs that support flow structures. The proportionality between body heat loss and body size raised to the power 3/4 is deduced from the discovery that the counterflow of two trees is the optimal configuration for achieving(i) and (ii) simultaneously: maximum fluid-flow access and minimum heat leak. Other allometric examples deduced from the constructal law are the flying speeds of insects, birds and aeroplanes, the porosity and hair strand diameter of the fur coats of animals, and the existence of optimal organ sizes. Body size and configuration are intrinsic parts of the deduced configuration. They are results, not assumptions. The constructal law extends physics(thermodynamics) to cover the configuration, performance, global size and global internal flow volume of flow systems. The time evolution of such configurations can be described as survival by increasing performance,compactness and territory.
Circulatory variables and the flight performance of birds
Authors: Bishop Charles M. 
Published: April 2005

SUMMARYWhen considering the `burst' flight performance of birds, such as during take-off, one of the most important structural variables is the ratio of the mass of the flight muscle myofibrils with respect to body mass. However, when considering `prolonged' flight performance the variable of interest should be the body mass ratio of the mass of the flight muscle myofibrils that can be perfused sustainably with metabolites via the blood supply. The latter variable should be related to blood flow (ml min-1), which in turn has been shown to be a function of heart muscle mass, the value of which is more easily obtainable for different species than that for the mass of perfused muscle.The limited empirical evidence available suggests that for birds and mammals the rate of maximum oxygen consumption scales with heart mass(Mh) as Mh0.88and that for birdsMh scales with body mass (Mb) as Mb0.92, leading to the conclusion that the rate of maximum oxygen consumption in birds scales with an exponent of around Mb0.82. A similar exponent would be expected for the rate of maximum oxygen consumption with respect to the flight muscle mass of birds. This suggests that the sustainable power output from the flight muscles may ultimately be limiting the flight performance of very large flying animals, but as a result of circulatory constraints rather than biomechanical considerations of the flight musclesper se.Under the particular circumstances of sustainable flight performance,calculations of rates of metabolic energy consumed by the flight muscles can be compared directly with the estimates of biomechanical power output required, as calculated using various aerodynamic models. The difference between these calculated values for rates of energy input and output from the muscles is equivalent to the `apparent' mechanochemical conversion efficiency. The results of one such analysis, of the maximum sustainable flight performance of migratory birds, leads to the conclusion that the efficiency of the flight muscles appears to scale as Mb0.14. However, much of this apparent scaling may be an artefact of the application and assumptions of the models. The resolution of this issue is only likely to come from studying bird species at either extreme of the size range.
The origin of allometric scaling laws in biology from genomes to ecosystems: towards a quantitative unifying theory of biological structure and organization
Authors: West Geoffrey B. , Brown James H. 
Published: April 2005

SUMMARYLife is the most complex physical phenomenon in the Universe, manifesting an extraordinary diversity of form and function over an enormous scale from the largest animals and plants to the smallest microbes and subcellular units. Despite this many of its most fundamental and complex phenomena scale with size in a surprisingly simple fashion. For example, metabolic rate scales as the 3/4-power of mass over 27 orders of magnitude, from molecular and intracellular levels up to the largest organisms. Similarly, time-scales (such as lifespans and growth rates) and sizes (such as bacterial genome lengths,tree heights and mitochondrial densities) scale with exponents that are typically simple powers of 1/4. The universality and simplicity of these relationships suggest that fundamental universal principles underly much of the coarse-grained generic structure and organisation of living systems. We have proposed a set of principles based on the observation that almost all life is sustained by hierarchical branching networks, which we assume have invariant terminal units, are space-filling and are optimised by the process of natural selection. We show how these general constraints explain quarter power scaling and lead to a quantitative, predictive theory that captures many of the essential features of diverse biological systems. Examples considered include animal circulatory systems, plant vascular systems, growth,mitochondrial densities, and the concept of a universal molecular clock. Temperature considerations, dimensionality and the role of invariants are discussed. Criticisms and controversies associated with this approach are also addressed.
Application of Numerical and Experimental Techniques for the Aero-Acoustic Characterisation of a Car Rear-View Mirror
Authors: Reichl Christoph , Krenn Christian , Mann Martin , Lang Hermann 
Published: April 2005

Numerical as well as experimental approaches are used to capture aero-acoustic characteristics of a car rear-view mirror. The numerical study splits up into several parts. Using an actual production mirror, particular emphasis must be put on the geometry preparation and mesh generation. Initially, a CFD simulation of the entire car aerodynamics is performed to extract the proper flow boundary conditions for the aero-acoustic simulation of a smaller section surrounding the mirror. Pressure fluctuations on the surfaces extracted during an LES generate the data base required for the aeroacoustic post-processing. The acoustic pressure at several monitoring points is then calculated using Lighthill's Acoustic Analogy. To include refraction effects of the nearby surfaces a direct BEM approach is also employed. Utilizing the PIV method, local areas of increased turbulence are identified experimentally. Microphone measurements with and without the exterior mirror are performed.
Shoulder hemiarthroplasty in patients with juvenile idiopathic arthritis
Authors: Thomas S. , Price A. J. , Sankey R. A. , Thomas M. 
Published: April 2005

Replacement of the shoulder in juvenile idiopathic arthritis is not often performed and there have been no published series to date. We present nine glenohumeral hemiarthroplasties in eight patients with systemic or polyarticular juvenile idiopathic arthritis. The mean follow-up was six years (59 to 89 months). The mean age at the time of surgery was 32 years. Surgery took place at a mean of 27 years after diagnosis. The results indicated excellent relief from pain. There was restoration of useful function which deteriorated with time, in part because of progression of the systemic disease in this severely affected group. No patient has required revision to date and there has been no radiological evidence of loosening or osteolysis around the implants. We discuss the pathoanatomical challenges unique to this group. There was very little space for a prosthetic joint and, in some cases, bony deformity and the small size necessitated the use of custom-made implants.
EBRA-FCA for measurement of migration of the femoral component in surface arthroplasty of the hip
Authors: Beaulé P. E. , Krismer M. , Mayrhofer P. , Wanner S. , Le Duff M. , Mattesich M. , Stoeckl B. , Amstutz H. C. , Biedermann R. 
Published: April 2005

Studies on the migration of an implant may be the only way of monitoring the early performance of metal-on-metal prostheses. The Ein Bild Roentgen Analyse - femoral component analysis (EBRA-FCA) method was adapted to measure migration of the femoral component in a metal-on-metal surface arthroplasty of the hip using standard antero-posterior radiographs. In order to determine the accuracy and precision of this method a prosthesis was implanted into cadaver bones. Eleven series of radiographs were used to perform a zero-migration study. After adjustment of the femoral component to simulate migration of 3 mm the radiographs were repeated. All were measured independently by three different observers. The accuracy of the method was found to be ± 1.6 mm for the x-direction and ± 2 mm for the y-direction (95% percentile). The method was validated using 28 hips with a minimum follow-up of 3.5 years after arthroplasty. Seventeen were sound, but 11 had failed because of loosening of the femoral component. The normal (control) group had a different pattern of migration compared with that of the loose group. At 29.2 months, the control group showed a mean migration of 1.62 mm and 1.05 mm compared with 4.39 mm and 4.05 mm in the failed group, for the centre of the head and the tip of the stem, respectively (p = 0.001). In the failed group, the mean time to migration greater than 2 mm was earlier than the onset of clinical symptoms or radiological evidence of failure, 19.1 versus 32.2 months (p = 0.001) and 24.8 months (p = 0.012), respectively. EBRA-FCA is a reliable and valid tool for measuring migration of the femoral component after surface arthroplasty and can be used to predict early failure of the implant. It may be of value in determining the long-term performance of surface arthroplasty.
Metal ion levels after metal-on-metal proximal femoral replacements
Authors: Dunstan E. , Sanghrajka A. P. , Tilley S. , Unwin P. , Blunn G. , Cannon S. R. , Briggs T. W. R. 
Published: April 2005

Metal-on-metal hip bearings are being implanted into younger patients. The consequence of elevated levels of potentially carcinogenic metal ions is therefore a cause for concern. We have determined the levels of cobalt (Co), chromium (Cr), titanium (Ti) and vanadium (Va) in the urine and whole blood of patients who had had metal-on-metal and metal-on-polyethylene articulations in situ for more than 30 years. We compared these with each other and with the levels for a control group of subjects. We found significantly elevated levels of whole blood Ti, Va and urinary Cr in all arthroplasty groups. The whole blood and urine levels of Co were grossly elevated, by a factor of 50 and 300 times respectively in patients with loose metal-on-metal articulations when compared with the control group. Stable metal-on-metal articulations showed much lower levels. Elevated levels of whole blood or urinary Co may be useful in identifying metal-on-metal articulations which are loose.
Repair of large full-thickness articular cartilage defects in the rabbit
Authors: Yanai T. , Ishii T. , Chang F. , Ochiai N. 
Published: April 2005

We produced large full-thickness articular cartilage defects in 33 rabbits in order to evaluate the effect of joint distraction and autologous culture-expanded bone-marrow-derived mesenchymal cell transplantation (ACBMT) at 12 weeks. After fixing the knee on a hinged external fixator, we resected the entire surface of the tibial plateau. We studied three groups: 1) with and without joint distraction; 2) with joint distraction and collagen gel, and 3) with joint distraction and ACBMT and collagen gel. The histological scores were significantly higher in the groups with ACBMT collagen gel (p < 0.05). The area of regenerated soft tissue was smaller in the group allowed to bear weight (p < 0.05). These findings suggest that the repair of large defects of cartilage can be enhanced by joint distraction, collagen gel and ACBMT.
The care of pin sites with external fixation
Authors: Davies R. , Holt N. , Nayagam S. 
Published: April 2005

Two protocols for the operative technique and care of the pin-site with external fixation were compared prospectively. There was a total of 120 patients with 46 in group A and 74 in group B. Infection was defined as an episode of pain or inflammation at a pin site, accompanied by a discharge which was either positive on bacterial culture or responded to a course of antibiotics. Patients in group B had a lower proportion of infected pin sites (p = 0.003) and the time to the first episode of infection was longer (p < 0.001). The risk of pin-site infection is lower if attention is paid to avoiding thermal injury and local formation of haematoma during surgery and if after-care includes the use of an alcoholic antiseptic and occlusive pressure dressings.
Intervertebral disc degeneration associated with lumbosacral transitional vertebrae
Authors: Aihara T. , Takahashi K. , Ogasawara A. , Itadera E. , Ono Y. , Moriya H. 
Published: April 2005

We studied 52 patients, each with a lumbosacral transitional vertebra. Using MRI we found that the lumbar discs immediately above the transitional vertebra were significantly more degenerative and those between the transitional vertebrae and the sacrum were significantly less degenerative compared with discs at other levels. We also performed an anatomical study using 70 cadavers. We found that the iliolumbar ligament at the level immediately above the transitional vertebra was thinner and weaker than it was in cadavers without a lumbosacral transitional vertebra. Instability of the vertebral segment above the transitional vertebra because of a weak iliolumbar ligament could lead to subsequent disc degeneration which may occur earlier than at other disc levels. Some stability between the transitional vertebra and the sacrum could be preserved by the formation of either an articulation or by bony union between the vertebra and the sacrum through its transverse process. This may protect the disc from further degeneration in the long term.
Hepatitis A–Related Mortality in California, 1989–2000: Analysis of Multiple Cause–Coded Death Data
Authors: Wise Matthew E. , Sorvillo Frank 
Published: April 2005

Objectives. We estimated the hepatitis A (HA) mortality rate in California, assessed demographic differences in HA-related mortality, and examined comorbidities listed on death certificates in order to provide information for health policy and planning related to HA vaccination. Methods. We identified HA-related deaths in California from 1989 to 2000 with multiple-cause-of-death files and calculated mortality rates and rate ratios. Results. We identified 402 HA-related deaths between 1989 and 2000; the annual age-adjusted HA-related mortality rate was 1.20 deaths per 1 million persons. Older individuals, men, Latinos, and American Indians/Alaska Natives had elevated mortality rates. Liver conditions and non-A viral hepatitis infections were more common among HA-related deaths than among all other deaths. Conclusions. Current immunization practices should be reevaluated and the expansion of current vaccination guidelines for groups that have elevated HA-related mortality rates should be considered.
“I Have an Evil Child at My House”: Stigma and HIV/AIDS Management in a South African Community
Authors: Campbell Catherine , Foulis Carol Ann , Maimane Sbongile , Sibiya Zweni 
Published: April 2005

We examined the social roots of stigma by means of a case study of HIV/AIDS management among young people in a South African community (drawing from interviews, focus groups, and fieldworker diaries). We highlight the web of representations that sustain stigma, the economic and political contexts within which these representations are constructed, and the way in which they flourish in the institutional contexts of HIV/AIDS interventions. Stigma serves as an effective form of “social psychological policing” by punishing those who have breached unequal power relations of gender, generation, and ethnicity. We outline an agenda for participatory programs that promote critical thinking about stigma’s social roots to stand alongside education and, where possible, legislation as an integral part of antistigma efforts.
Evaluating the Safety of New Vaccines: Summary of a Workshop
Authors: Ellenberg Susan S. , Foulkes Mary A. , Midthun Karen , Goldenthal Karen L. 
Published: April 2005

Public concerns about the safety of vaccines arise on a regular basis. In November 2000, a workshop titled “Evaluation of New Vaccines: How Much Safety Data?” was convened by US Public Health Service agencies, including the Food and Drug Administration, the National Institutes of Health, the Centers for Disease Control and Prevention, and the Health Resources and Services Administration, to discuss appropriate methods for evaluating the safety of new vaccines. Workshop presentations addressed the current standards and approaches for new vaccine evaluation and postlicensure surveillance, as well as public views about vaccine safety and alternative approaches that could be considered. The advantages and disadvantages of conducting large controlled trials before licensure or widespread use of a new vaccine were discussed. We summarize these presentations and discussions.
Passive Immunization Against Poliomyelitis
Authors: Rinaldo Charles R. 
Published: April 2005

Poliomyelitis has gone from being one of the worst scourges of the 20th century to nearing eradication in the 21st. This success is well known to be attributable to the Salk inactivated and Sabin attenuated poliovirus vaccines. However, before introduction of these vaccines, William McDowall Hammon of the University of Pittsburgh Graduate School of Public Health led the first major breakthrough in prevention of the disease by using passive immunization in one of the earliest double-blind, placebo-controlled clinical trials. This study provided the first evidence that antibodies to poliovirus could prevent the disease in humans.
Disparities in Indigenous Health: A Cross-Country Comparison Between New Zealand and the United States
Authors: Bramley Dale , Hebert Paul , Tuzzio Leah , Chassin Mark 
Published: April 2005

Objectives. We compared the health statuses of the indigenous populations of New Zealand and the United States with those of the numerically dominant populations of these countries. Methods. Health indicators compared included health outcome measures, preventive care measures, modifiable risk factor prevalence, and treatment measures. Results. In the case of nearly every health status indicator assessed, disparities (both absolute and relative) were more pronounced for Maoris than for American Indians/Alaska Natives. Both indigenous populations suffered from disparities across a range of health indicators. However, no disparities were observed for American Indians/Alaska Natives in regard to immunization coverage. Conclusions. Ethnic health disparities appear to be more pronounced in New Zealand than in the United States. These disparities are not necessarily intractable. Although differences in national health sector responses exist, New Zealand may be well placed in the future to evaluate the effectiveness of new strategies to reduce these disparities given the extent and quality of Maori-specific health information available.
Correlates of Cigarette Smoking Among Selected Southwest and Northern Plains Tribal Groups: The AI-SUPERPFP Study
Authors: Nez Henderson Patricia , Jacobsen Clemma , Beals Janette ,   the AI-SUPERPFP Team
Published: April 2005

Objectives. We describe the prevalence and correlates of cigarette smoking in 2 American Indian tribal groups. Methods. We performed multinomial logistic regression on epidemiological data from a population-based, cross-sectional study of Southwest and Northern Plains American Indians aged 15 to 54 years. Results. We found that 19% of Southwest men, 10% of Southwest women, 49% of Northern Plains men, and 51% of Northern Plains women were current smokers. Male gender and younger age were associated with higher odds of smoking in the Southwest tribe, whereas current or former marriage and having spent less time on a reservation were associated with higher odds of smoking in the Northern Plains population. Alcohol consumption was strongly associated with higher odds of smoking in both groups. Conclusions. Cigarette smoking is a major public health concern among American Indians. Because correlates and smoking patterns vary among different tribal groups, each group’s unique characteristics should be considered when designing and implementing comprehensive, culturally appropriate interventions in American Indian communities.