bluuebunny/crossref_metadata_2025_split huggingface dataset:
AUTOMORPHISMS OF THE CATEGORY OF THE FREE NILPOTENT GROUPS OF THE FIXED CLASS OF NILPOTENCY
Authors: TSURKOV A. 
Published: September 2007

This paper is motivated by the following question arising in universal algebraic geometry: when do two algebras have the same geometry? This question requires considering algebras in a variety Θ and the category Θ0of all finitely generated free algebras in Θ. The key problem is to study how far the group Aut Θ0of all automorphisms of the category Θ0is from the group Inn Θ0of inner automorphisms of Θ0(see [7, 10] for details). Recall that an automorphism ϒ of a category 𝔎 is inner, if it is isomorphic as a functor to the identity automorphism of the category 𝔎.Let Θ = 𝔑dbe the variety of all nilpotent groups whose nilpotency class is ≤ d. Using the method of verbal operations developed in [8, 9], we prove that every automorphism of the category [Formula: see text], d ≥ 2 is inner.
A MATHEMATICAL MODEL OF IMMUNE RESPONSE IN CUTANEOUS LEISHMANIASIS
Authors: DE ALMEIDA MARCOS C. , MOREIRA HELMAR N. 
Published: September 2007

The TH1/TH2 paradigm has been largely used in the interpretation of several diseases, particularly in leishmaniasis. As far as we know there is no mathematical description of this model related to leishmaniasis. We have extended and modified a previous published set of equations1in order to adapt it to leishmanial disease particularities. The main modifications were: (1) the analysis of logistic and exponential parasite growth curves, (2) the assumption of the TH2 arm of the immune response having a positive action on parasite growth. The set of three simultaneous differential equations describing the TH1 arm, TH2 arm and parasite growth were analyzed for conditions of existence and stability of the solutions.Stable solutions valid for the logistic and exponential parasite growth models, with its possible clinical correlations, were obtained in the following situations: (1) parasite and TH2 extinction [TH1 cure], (2) parasite extinction and TH1/TH2 co-existence [TH1/TH2 cure], (3) TH1 and parasite co-existence, TH2 extinction [stable TH1 infection], and (4) TH1, TH2 and parasite co-existence [stable TH1/TH2 infection]. TH2 and parasite co-existence associated to TH1 extinction [stable TH2 infection] was obtained only with the logistic growth model. The model also provides an alternative hypothesis for TH1 bias in resistant mice and emphazises the importance of natural immunity for the existence of chronic states.
Attitudes to and knowledge about pain and pain management, of nurses working with children with cancer: A comparative study between UK, South Africa and Sweden
Authors: Enskär Karin , Ljusegren Gunilla , Berglund Gimbler , Eaton Nicola , Harding Rosemary , Mokoena Joyce , Chauke Motshedisi , Moleki Maria 
Published: September 2007

Pain is among the most common effects of cancer and its treatment. Children and young people with cancer often consider pain from procedures and treatment to be the worst aspect of their illness. This study aimed to i) identify and describe knowledge and attitudes to pain and pain management amongst nurses working with children with cancer and ii) compare the perspectives on pain and pain management of nurses from UK, South Africa and Sweden. 106 nurses working with children with cancer in UK, South Africa and Sweden completed Salanterä's (1999) questionnaire on nurses' attitudes to pain in children. Nurses had good levels of knowledge and positive attitudes to pain management, with Swedish nurses' having higher levels of knowledge and a more positive attitude to pain management than nurses from UK or South Africa. A high level of knowledge was correlated to a more positive attitude to pain management. Knowledge levels need to be improved to ensure more positive attitudes to pain management, especially for nurses in South Africa. Swedish nurses' level of knowledge about non-pharmacological pain management strategies has scope for improvement. British nurses may need to focus more on the sociology and psychology of pain.
Design of a piecewise linear vibration isolator for jump avoidance
Authors: Jazar G N , Mahinfalah M , Deshpande S 
Published: September 2007

Piecewise linear isolators are smart passive vibration isolators that provide effective isolation for high frequency/low amplitude excitation. This can be done by introducing a soft primary suspension and a relatively damped secondary suspension. Such a piecewise isolator prevents the system from a high relative displacement in low frequency/high amplitude excitation. By employed an averaging method it is possible to obtain an implicit function for frequency response of a symmetric bilinear vibration isolator system under steady-state harmonic excitation. This function is examined for jump avoidance. A condition is derived which when met ensures that the undesirable phenomenon of ‘jump’ does not occur and the system response is functional. The jump avoidance and sensitivity of the condition are examined and investigated as the dynamic parameters vary. The results of this investigation can be directly employed in design of effective piecewise linear vibration isolators. A linear vibration system is defined as one in which the quantities of mass (or inertia), stiffness, and damping are linear in behaviour and do not vary with time [1]. Although mathematical models employing a linear ordinary differential equation with constant coefficients portray a simple and manageable system for analytical study, in most cases they are an incomplete representation simplified for the sake of analysis. Most real physical vibration systems are more accurately depicted by non-linear governing equations, in which the non-linearity may stem from structural constraints causing a change in stiffness and damping characteristics, or from inherent non-linear behaviour of internal springs and dampers. This paper focuses on a general form of such a non-linear system. This study of piecewise-linear systems will allow hazardous system behaviour over operating frequency ranges to be gauged and controlled in order to avoid premature fatigue damage, and prolong the life of the system.
Using Bézier splines for design optimization of cams regarding valve train dynamics
Authors: Scheucher R , Hellinger W 
Published: September 2007

The aim of this work is to present an optimization problem to design cams for automotive valve trains. The constrained optimization problem uses the control points of the cam profile as design variables. The cam profile is represented by harmonic splines. In addition to the optimization problem the advantages of the calculation of sensitivity information using the direct are determined. The valve train model is defined by a multi-body system containing discontinuities because of the loss of contact between two consecutive components of the valve train. The objective is to maximize the area below the valve lift, which has a great influence on the gas flow. Constraints for dynamic force, the valve opening and closing phase and the valve lift based on the engine's thermodynamics considerations are taken into account. Furthermore, some constraints for the geometric coordinates of the control points of the cam profile must be imposed.
Experimental and finite element analyses of a sliding-tube-type driveshaft-induced vehicle vibration
Authors: Juang T B , Cheng M , Na L 
Published: September 2007

Driveline noise, vibration, and harshness (NVH) has become an integral attribute in defining how the vehicle NVH performance is perceived by the customers of the automotive industry. The driveshaft component design requirements need to make sure that the designed driveline system is robust and reliable in order to achieve the vehicle NVH targets. They also need to ensure that the system maintains its durability performance as well. A slip mechanism in the driveline system is needed to accommodate the movements caused by the rear axle and rear suspensions when the vehicle travels on a rough road or accelerates/ decelerates abruptly. One design option to accommodate the slip mechanism is to use a press-fitted sliding-tube design. This slip mechanism causes the fluctuation of the contact forces in the tubes, particularly in the vehicle coast down course, and becomes a non-linear contact force phenomenon. This paper uses experimental and finite element method linear tools to explain the non-linear behaviour of the sliding-tube driveshaft, and to provide design options to prevent vehicle vibration issues created by the current sliding-tube driveshaft design.
Steady-state stability and bifurcations of friction oscillators due to velocity-dependent friction characteristics
Authors: Hetzler H , Schwarzer D , Seemann W 
Published: September 2007

This article presents an analytical investigation on stability and bifurcation behaviour due to an exponential and a generalized friction characteristics in the sliding domain of a simple friction oscillator, which is commonly referred to as ‘mass-on-a-belt’ oscillator. The friction is described by a friction coefficient which depends on the relative velocity between the two tribological partners. The standard way of examining the steady-state only gives very rough insight in the behaviour and is not able to provide further informations about the steady-state's basin of attraction or about limit-cycles. It is found that the system may undergo bifurcations of Hopf type. Hereby, the character of the bifurcations strongly depends on the parameters of the friction characteristic.
Trabecular Bone Gradient in Rat Long Bone Metaphyses: Mathematical Modeling and Application to Morphometric Measurements and Correction of Implant Positioning
Authors: Gabet Yankel , Kohavi David , Kohler Thomas , Baras Mario , Müller Ralph , Bab Itai 
Published: September 2007

Abstract
The distribution of trabecular structures in mammalian long bone metaphyses has been insufficiently explored. We show in rats that the trabecular bone structural parameters display a decreasing gradient, toward the diaphysis, that can be defined mathematically. This gradient is applicable for optimizing the reference volume in metabolic studies and for retrospective correction of implant positioning.
Introduction: The mammalian metaphyseal trabecular bone is unevenly distributed. Hence, defining a standard reference volume is critical for morphometric analyses in metaphyseal sites.
Materials and Methods: The distal femoral and proximal tibial metaphyses of adult orchietomized (ORX) or sham-ORX rats were scanned by νCT 6 wk postoperatively. Morphometric analysis based on 3D image data was performed in 450-νm-thick transversal segments defined consecutively from the primary spongiosa toward the diaphysis. The results were subjected to curve-fit analysis. A similar approach was used for proximal tibial metaphyseal sites carrying titanium implants inserted horizontally 6 wk post-ORX and examined 2-12 wk after implantation.
Results: The respective curve-fit analysis in both femur and tibia revealed decreasing linear/quadratic and logarithmic gradients for all morphometric parameters in the sham-ORX animals. The ORX animals showed similar gradients with roughly similar slopes but lower values. For the bone volume (BV/TV) and connectivity (Conn.D) densities, the magnitude of the ORX effect vastly increased toward the diaphysis. The trabecular number was unaffected in ORX femora and tibias. The trabecular thickness showed a constant decrease in the femur and was unchanged in the tibia. These findings are useful for the determination and reporting of reference volumes in morphometric studies. Implementing the curve-fit analysis for retrospective correction of implant positioning revealed differences in BV/TV, Tb.N, Conn.D, and percent implant surface in contact with bone (%OI) between the sham-ORX and ORX rats. These differences were otherwise undisclosed. In addition, a temporal increase in %OI was shown only for the corrected measurements.
Conclusions: We show the feasibility of modeling trabecular bone structures using mathematical tools. Such modeling may be used as an experimental tool. Moreover, if proven applicable to human skeletal structures, it may be further developed for the diagnosis of metabolic bone diseases and evaluation of therapeutic measures.
Comparison of Densitometric and Radiographic Vertebral Fracture Assessment Using the Algorithm-Based Qualitative (ABQ) Method in Postmenopausal Women at Low and High Risk of Fracture
Authors: Ferrar Lynne , Jiang Guirong , Clowes Jackie A , Peel Nicola F , Eastell Richard 
Published: September 2007

Abstract
Using ABQ diagnosis, the sensitivity to detect VF of densitometric versus radiographic assessment in 755 postmenopausal women was 71-81% and specificity was 97%. Misdiagnosis was influenced by image quality and was more common for mild deformities.
Introduction: Using densitometric vertebral fracture assessment (VFA), prevalent fractures are identified when vertebral height appears reduced by ≥20%. However, this approach does not discriminate between osteoporotic vertebral fracture (VF) and nonosteoporotic deformity, which increases the false-positive rate. Algorithm-based qualitative diagnosis (ABQ) focuses on vertebral endplate fracture to exclude these deformities but has not been applied in VFA. We wished to determine whether densitometric image quality is adequate for ABQ assessment. Our aims were to (1) calculate agreement between VFA and radiography using ABQ to identify prevalent VF and (2) identify the primary reasons for any discordant diagnosis.
Methods: Radiographic and densitometric spine images for postmenopausal women at low risk (LR; n = 459) and high risk (HR; n = 298) of VF were assessed using ABQ. Agreement between imaging modalities for VF diagnosis was assessed by κ statistics using ABQ radiographic readings as the gold standard.
Results: The prevalence of VF was 11-29% (radiography) and 9-26% (VFA) in the LR and HR groups, respectively. Agreement between imaging modalities was good or very good (κ = 0.62-0.81 in the LR and HR populations). The sensitivity to detect women with VF by VFA was 71% and 84% in the LR and HR populations, respectively, and specificity was 97%. Fifty-two (77%) and 60 (61%) of vertebrae misclassified by VFA in the LR and HR populations were mild fractures and 37 (54%) and 62 (63%) were wedge fractures. One third of fractures missed by VFA were related to poor or unreadable image quality (n = 27 and 28 vertebrae in the LR and HR populations, respectively).
Conclusions: There was good agreement between VFA and radiography using ABQ to identify prevalent VF in women at LR or HR of osteoporotic VF. Vertebrae misclassified by VFA were primarily mild fractures or deformities, and two thirds of all fractures missed by VFA were related to poor or unreadable image quality.
Calcifications in the Abdominal Aorta Predict Fractures in Men: MINOS Study
Authors: Szulc Pawel , Kiel Douglas P , Delmas Pierre D 
Published: September 2007

Abstract
In a cohort of 781 men ≥50 yr of age followed up for 10 yr, extended calcifications in the abdominal aorta were associated with a 2- to 3-fold increase in the risk of osteoporotic fractures regardless of BMD and falls.
Introduction: Cardiovascular disease and osteoporotic fractures are public health problems that frequently coexist.
Materials and Methods: We assessed the relation of the severity of aortic calcifications with BMD and the risk of fracture in 781 men ≥50 yr of age. During a 10-year follow-up, 66 men sustained incident clinical fractures. Calcifications in the abdominal aorta expressed as an aortic calcification score (ACS) were assessed by a semiquantitative method. BMD was measured at the lumbar spine, hip, whole body, and distal forearm.
Results: ACS &gt; 2 was associated with a 2-fold increase in the mortality risk after adjustment for age, weight, smoking, comorbidity, and medications. After adjustment for age, body mass index (BMI), smoking, and comorbidity, men in the highest quartile of ACS (&gt;6) had lower BMD of distal forearm, ultradistal radius, and whole body than men in the lower quartiles. Log-transformed ACS predicted fractures when adjusted for age, BMI, age by BMI interaction, prevalent fractures, BMD, and history of two or more falls (e.g., hip BMD; OR = 1.44; p &lt; 0.02). ACS, BMD at all the skeletal sites, and history of two or more falls were independent predictors of fracture. Men with ACS &gt; 6 had a 2- to 3-fold increased risk of fracture after adjustment for confounding variables (OR = 2.54-3.04; p &lt; 0.005-0.001 according to the site).
Conclusions: This long-term prospective study showed that elevated ACS (&gt;6) is a robust and independent risk factor for incident fracture in older men regardless of age, BMI, BMD, prevalent fractures, history of two or more falls, comorbidities, and medications.
Effects of Raloxifene on Fracture Risk in Postmenopausal Women: The Raloxifene Use for The Heart Trial
Authors: Ensrud Kristine E , Stock John L , Barrett-Connor Elizabeth , Grady Deborah , Mosca Lori , Khaw Kay-Tee , Zhao Qingwen , Agnusdei Donato , Cauley Jane A 
Published: September 2007

Abstract
Using data from a randomized placebo-controlled trial of 10,101 postmenopausal women not selected on the basis of osteoporosis, we examined whether the effect of raloxifene treatment on fractures was consistent across categories of fracture risk. Treatment with raloxifene for 5 yr reduced the risk of clinical vertebral fractures, but not nonvertebral fractures, irrespective of the presence or absence of risk factors for fracture.
Introduction: In The Raloxifene Use for The Heart (RUTH) trial, women assigned to raloxifene had a lower risk of clinical vertebral fractures but not nonvertebral fractures. However, it is uncertain whether the effect of raloxifene on fractures in this population not selected for low BMD differs according to risk factors for fractures.
Materials and Methods: We randomly assigned 10,101 postmenopausal women ≥55 yr of age with documented coronary heart disease or at high risk for coronary events to 60 mg raloxifene daily or placebo and followed them for a median of 5.6 yr. Fractures (nonvertebral and clinical vertebral) were prespecified secondary endpoints that were reported at semiannual visits. Fractures were adjudicated and confirmed using X-ray reports or medical records.
Results: There was no difference between raloxifene and placebo groups in risk of nonvertebral fractures (428 versus 438 events; hazard ratio [HR], 0.96; 95% CI, 0.84-1.10), including hip/femur (89 versus 103 events; HR, 0.85; 95% CI, 0.64-1.13) and wrist (107 versus 111 events; HR, 0.95; 95% CI, 0.73-1.24) fractures. Women treated with raloxifene had a lower risk of clinical vertebral fractures (64 versus 97 events; HR, 0.65; 95% CI, 0.47-0.89). The effect of treatment with raloxifene on risk of nonvertebral and clinical vertebral fractures was consistent across fracture risk categories defined at baseline by age, smoking status, physical activity level, prior history of fracture, family history of hip fracture, diabetes mellitus, previous use of hormone therapy, thyroid hormone use, statin use, weight loss, body mass index, or fracture specific summary risk score.
Conclusions: In older women with or at high risk of coronary heart disease not selected on the basis of osteoporosis or increased fracture risk, treatment with raloxifene for 5 yr reduced the risk of clinical vertebral fractures, but not nonvertebral fractures, irrespective of presence or absence of risk factors for fracture.
Race and Ethnic Variation in Proximal Femur Structure and BMD Among Older Men
Authors: Marshall Lynn M , Zmuda Joseph M , Chan Benjamin KS , Barrett-Connor Elizabeth , Cauley Jane A , Ensrud Kristine E , Lang Thomas F , Orwoll Eric S ,   for the Osteoporotic Fractures in Men (MrOS) Research Group
Published: September 2007

Abstract
Femoral neck dimensions and vBMD from QCT were compared among 3305 black, Asian, Hispanic, and white men ≥65 yr of age. All had similar stature-adjusted mean femoral neck volume, but black and Asian men had thicker cortices and higher trabecular vBMD, which may increase bone strength.
Introduction: Hip fracture rates among elderly U.S. black and Asian men are lower than rates among white men. Structural characteristics or volumetric BMD (vBMD), which confer advantages for femoral neck bone strength, may vary by race/ethnicity. However, this topic has not been studied in detail.
Materials and Methods: In a cross-sectional study, dimensions and vBMD in the femoral neck and shaft were obtained from QCT scans among 3305 men ≥65 yr of age in the Osteoporotic Fractures in Men (MrOS) study. Femoral neck measures were cross-sectional area; integral, cortical, and medullary volumes and integral, cortical, and trabecular vBMD. Shaft measures were cross-sectional, cortical, and medullary areas and cortical vBMD. Self-reported race/ethnicity was classified as black, Asian, Hispanic, or white. We used multivariable linear regression models with adjustment for age, height, and body mass index to compare means of the outcome measures in black, Asian, and Hispanic men to those in whites.
Results: All groups had similar femoral neck integral volume. Among black and Asian men, mean cortical volume as a percent of integral volume was 6% greater, integral vBMD was 6-10% greater, and trabecular vBMD was 33-36% greater than means among whites. Shaft cross-sectional area was similar among blacks, but smaller among Asians, compared with whites. However, mean shaft cortical area was greater among blacks but similar among Asians and whites, resulting in mean cortical thickness being 5% greater among black and Asian men. Blacks also had greater mean cortical vBMD in both the femoral neck and shaft.
Conclusions: Black and Asian men ≥65 yr of age have features in the proximal femur that may confer advantages for bone strength. Specifically, greater cortical thickness and higher trabecular vBMD among black and Asian men could help explain the lower hip fracture rates in these populations. Discerning the mechanisms underlying these differences could provide advances for the prevention and treatment of osteoporosis.
Effect of acute hyperinsulinaemia with and without angiotensin II type 1 receptor blockade on resistin and adiponectin concentrations and expressions in healthy subjects
Authors: Krušinová E , Klementová M , Kopecký J , Wohl P , Kazdová L , Mlejnek P , Pravenec M , Hill M , Pelikánová T 
Published: September 2007

Objective: The potential insulin-sensitizing function of angiotensin II type 1 receptor blockade (ARB) with regard to selected adipokines is not fully explained so far. Our study aimed to explore the influence of acute hyperinsulinaemia and acutely induced ARB on resistin and adiponectin concentrations and expressions in healthy subjects.
Design and methods: Plasma adipokines were measured: 1) at 0, 30 and 240 min of hyperinsulinaemic (1 mU/kg per min) euglycaemic (5 mmol/l) clamp (HEC), and 2) during HEC after acute ARB (losartan 200 mg; AT-HEC) using the same protocol, in eight healthy subjects. Needle biopsy of abdominal s.c. fat was performed at 0, 30 and 240 min of both clamps to assess the adipokines’ expressions.
Results: Comparing the glucose disposals of HEC and AT-HEC, no difference in insulin sensitivity was found. Plasma resistin increased equally during HEC and AT-HEC (P < 0.05). The expression of resistin in s.c. fat increased during HEC (P < 0.05), while no significant changes in expression were observed during AT-HEC. Plasma levels of adiponectin did not change during both clamps. Adiponectin expression increased during HEC (P < 0.05), while it did not change during AT-HEC.
Conclusions: In healthy subjects, acute hyperinsulinaemia is associated with an increase in plasma resistin independently of ARB, while plasma adiponectin is not influenced by insulin or ARB. The expressions of both resistin and adiponectin in s.c. adipose tissue are stimulated by acute hyperinsulinaemia, whereas losartan attenuates their insulin-stimulated expressions. This suggests a potential effect of losartanon adipokines’ expression.