bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Robustness Analysis of Magneto-Rheological Tuned Vibration Absorbers Subject to Mass Off-Tuning
Authors: Koo Jeong-Hoi , Ahmadian Mehdi , Setareh Mehdi
Published: January 2006

This paper offers an experimental robustness analysis of a semi-active tuned vibration absorber (TVA) subject to structural mass off-tuning, which occurs frequently in practical applications of TVAs. One of the critical problems of a conventional TVA is off-tuning or miss-tuning because off-tuned TVAs may amplify the vibrations of the primary structure. This study intends to evaluate how well semi-active TVAs are able to adapt to structural mass changes (mass off-tuning) as compared with passive TVAs. To this end, a test apparatus was built to represent a two-degree-of-freedom structure model coupled with a TVA. The semi-active TVA considered in this study employed a magneto-rheological (MR) damper as its damping element to enhance overall performance. Using this test apparatus, a series of tests were conducted to identify the optimal tuning parameters of the TVAs. After obtaining each TVA’s optimal tuning parameters based on equal peak transmissibility criteria, the mass off-tuning tests were then performed on the optimally tuned TVAs. In order to off-tune the system, the mass of the primary structure varied from −19% to +19% of its nominal mass using a set of steel plates. Overall, the experimental results show that the semi-active MR TVA outperforms the passive TVA in reducing maximum vibrations. Moreover, the results show that the semi- active TVA is more robust to changes in the primary mass (mass off-tuning) The results further show that the semi-active MR TVA offers larger performance gains as the structure mass increases.
Biomechanical Modeling of Refractive Corneal Surgery
Authors: Alastrué V. , Calvo B. , Peña E. , Doblaré M.
Published: January 2006

The aim of refractive corneal surgery is to modify the curvature of the cornea to improve its dioptric properties. With that goal, the surgeon has to define the appropriate values of the surgical parameters in order to get the best clinical results, i.e., laser and geometric parameters such as depth and location of the incision, for each specific patient. A biomechanical study before surgery is therefore very convenient to assess quantitatively the effect of each parameter on the optical outcome. A mechanical model of the human cornea is here proposed and implemented under a finite element context to simulate the effects of some usual surgical procedures, such as photorefractive keratectomy (PRK), and limbal relaxing incisions (LRI). This model considers a nonlinear anisotropic hyperelastic behavior of the cornea that strongly depends on the physiological collagen fibril distribution. We evaluate the effect of the incision variables on the change of curvature of the cornea to correct myopia and astigmatism. The obtained results provided reasonable and useful information in the procedures analyzed. We can conclude from those results that this model reasonably approximates the corneal response to increasing pressure. We also show that tonometry measures of the IOP, underpredicts its actual value after PRK or LASIK surgery.
Numerical Modeling of In Vivo Plate Electroporation Thermal Dose Assessment
Authors: Becker S. M. , Kuznetsov A. V.
Published: January 2006

Electroporation is an approach used to enhance the transport of large molecules to the cell cytosol in which a targeted tissue region is exposed to a series of electric pulses. The cell membrane, which normally acts as a barrier to large molecule transport into the cell interior, is temporarily destabilized due to the development of pores in the cell membrane. Consequently, agents that are ordinarily unable enter the cell are able to pass through the cell membrane. Of possible concern when exposing biological tissue to an electric field is thermal tissue damage associated with joule heating. This paper explores the thermal effects of various geometric, biological, and electroporation pulse parameters including the blood vessel presence and size, plate electrode configuration, and pulse duration and frequency. A three-dimensional transient finite volume model of in vivo parallel plate electroporation of liver tissue is used to develop a better understanding of the underlying relationships between the physical parameters involved with tissue electroporation and resulting thermal damage potential.
Free Vibration of Thermally Buckled Composite Sandwich Plates
Authors: Shiau Le-Chung , Kuo Shih-Yao
Published: January 2006

A high precision triangular plate element is developed for the free vibration analysis of thermally buckled composite sandwich plates. Due to an uneven thermal expansion in the two principal material directions, the buckling mode of the plate may change from one pattern to another in the postbuckling region for certain fiber orientation and aspect ratio of the plate. Because of this buckle pattern change, the sequence of natural frequencies of the plate is also suddenly altered. By examining the buckling and free vibration modes of the plate, a clear picture of buckle pattern change and vibration mode shifting is presented. Numerical results show that if the shape of a free vibration mode is similar to the plate buckling mode then the natural frequency of that mode will drop to zero when the temperature reaches the buckling temperature.
Synthesis of Some N4-Substituted Derivatives of 1-[(S)-3-Hydroxy-2-(phosphonomethoxy)propyl]cytosine (HPMPC, Cidofovir)
Authors: Chalupová Šárka , Holý Antonín , Masojídková Milena
Published: January 2006

N4-Substituted derivatives of HPMPC were synthesized in four-step synthesis which included treatment of 4-methoxypyrimidin-2(1H)-one (1) with (S)-[(trityloxy)methyl]oxirane in DMF. Condensation of intermediary 1-[2-hydroxy-3-(trityloxy)propyl]-4-methoxypyrimidin-2(1H)-one (2) with (diisopropoxyphosphoryl)methyl tosylate in the presence of sodium hydride resulted in fully protected 4-methoxypyrimidin-2(1H)-one derivative 3 which gave on reaction with an appropriate primary amine in dioxane N4-substituted products 4a-4i. The reaction with bromotrimethylsilane simultaneously cleaved the trityl group and deprotected the phosphonate residue and gave the title HPMP analogues substituted at the cytosine amino group in position N4 5a-5i. Compound 4j was prepared from 4-methoxypyrimidin-2(1H)-one (1) by reaction with cyclopropylamine in dioxane. The intermediary 4-(cyclopropylamino)pyrimidin-2(1H)-one (6) then reacts with (S)-[(trityloxy)methyl]oxirane in DMF. Fully protected phosphonate 4j and its deprotected counterpart 5j was obtained by the same sequence of reactions as in the case of compounds 5a-5i.
Burnout as a predictor of self-reported sickness absence among human service workers: prospective findings from three year follow up of the PUMA study
Authors: Borritz M , Rugulies R , Christensen K B , Villadsen E , Kristensen T S
Published: January 2006

Aim:To investigate whether burnout predicts sickness absence days and sickness absence spells in human service workers.

Method:A total of 824 participants from an ongoing prospective study in different human service sector organisations were eligible for the three year follow up analysis. Burnout was measured with the work related burnout scale of the Copenhagen Burnout Inventory. Sickness absence was measured with self-reported number of days and spells during the last 12 months before the baseline and the follow up survey. A Poisson regression model with a scale parameter was used to account for over dispersion. A linear regression model was used for analysing changes in burnout and absence between baseline and follow up.

Results:Burnout was prospectively associated with both sickness absence days and sickness absence spells per year. Differences in sickness absence days varied from a mean of 5.4 days per year in the lowest quartile of the work related burnout scale to a mean of 13.6 in the highest quartile. An increase of one standard deviation on the work related burnout scale predicted an increase of 21% in sickness absence days per year (rate ratio 1.21, 95% CI 1.11 to 1.32) after adjusting for gender, age, organisation, socioeconomic status, lifestyle factors, family status, having children under 7 years of age, and prevalence of diseases. Regarding sickness absence spells, an increase of one standard deviation on the work related burnout scale predicted an increase of 9% per year (rate ratio 1.09, 95% CI 1.02 to 1.17). Changes in burnout level from baseline to follow up were positively associated with changes in sickness absence days (estimate 1.94 days/year, SE 0.63) and sickness absence spell (estimate 0.34 spells/year, SE 0.08).

Conclusion:The findings indicate that burnout predicts sickness absence. Reducing burnout is likely to reduce sickness absence.
Acute effects of force and vibration on finger blood flow
Authors: Bovenzi M , Welsh A J L , Della Vedova A , Griffin M J
Published: January 2006

Objectives:To investigate the effects of contact force at the finger on acute changes in finger circulation during exposure to vibration.

Methods:Each of 10 subjects attended 11 sessions in which they experienced five successive experimental 5-minute periods: (i) no force and no vibration; (ii) force and no vibration; (iii) force and vibration; (iv) force and no vibration; (v) no force and no vibration. During periods (ii) to (iv), the intermediate phalanx of the right middle finger applied one of two forces (2 N or 5 N) on a platform that vibrated during period (iii) at one of two frequencies: 31.5 Hz (at 4 or 16 ms−2r.m.s.) or 125 Hz (at 16 or 64 ms−2r.m.s.). Finger blood flow was measured in the exposed right middle finger, the unexposed right little finger, and the unexposed left middle fingers throughout the 25 minutes of each session.

Results:The application of force alone caused a reduction in finger blood flow in the exposed finger, but not other fingers. There were additional reductions in finger blood flow caused by vibration, with greater reductions at the higher vibration magnitudes at both frequencies but no difference between the two frequencies when using unweighted acceleration. The vibration caused a similar vasoconstriction in vibrated and non-vibrated fingers.

Conclusions:Modest levels of force applied by a finger can have a large effect on the finger blood flow, possibly due to the constriction of local blood vessels. The acute vascular effects of vibration cause additional reductions in finger blood flow that are not limited to the finger experiencing force and vibration. In all fingers (exposed and not exposed to vibration), the greater the magnitude of vibration, the greater the reduction in finger blood flow. In all fingers (exposed and not exposed to vibration), when the vibration was frequency weighted according to current standards, 125 Hz vibration caused greater reductions in finger blood flow than 31.5 Hz vibration.
Promoting excellent work ability and preventing poor work ability: the same determinants? Results from the Swedish HAKuL study
Authors: Lindberg P , Josephson M , Alfredsson L , Vingård E
Published: January 2006

Aim:Health has been described as a continuum between the two poles of excellent health and ill health. Research has so far focused on the negative pole, leaving knowledge about the positive pole vague. With a main focus on working life, the authors aim was to identify determinants promoting excellent work ability and determinants preventing poor work ability.

Methods:5638 (73% answering rate) employees in the public sector in Sweden answered a questionnaire both at baseline and at follow up 18 months later. The employees were divided into three groups based on sick leave at follow up: excellent work ability (13%), poor work ability (15%), and a middle group (72%). Self reported sociodemographic data, lifestyle data, and working life exposures at baseline were fitted into logistic regression models to determine which factors, if any, promoted excellent work ability or protected against poor work ability.

Results:Some determinants were mutual, but more than half of the determinants in the final model were associated solely with promoting excellent work ability or preventing poor work ability, thus creating different patterns of associations. Promotion of excellent work ability seemed more dependent on physical factors, clear work tasks, and positive feedback, while prevention of poor work ability seemed more dependent on job security and psychosocial factors.

Conclusions:This explorative longitudinal study showed slightly different patterns of determinants promoting excellent work ability and preventing poor work ability. As most of the identified determinants are amenable to influence, our results open up the possibility of interventions for promoting excellent work ability and preventing poor work ability.
Parkinson’s disease and other basal ganglia or movement disorders in a large nationwide cohort of Swedish welders
Authors: Fored C M , Fryzek J P , Brandt L , Nise G , Sjögren B , McLaughlin J K , Blot W J , Ekbom A
Published: January 2006

Introduction:Although it has been hypothesised that metal welding and flame cutting are associated with an increased risk for Parkinson’s disease due to manganese released in the welding fume, few rigorous cohort studies have evaluated this risk.

Methods:The authors examined the relation between employment as a welder and all basal ganglia and movement disorders (ICD-10, G20–26) in Sweden using nationwide and population based registers. All men recorded as welders or flame cutters (n = 49 488) in the 1960 or 1970 Swedish National Census were identified and their rates of specific basal ganglia and movement disorders between 1964 and 2003 were compared with those in an age and geographical area matched general population comparison cohort of gainfully employed men (n = 489 572).

Results:The overall rate for basal ganglia and movement disorders combined was similar for the welders and flame cutters compared with the general population (adjusted rate ratio (aRR) = 0.91 (95% CI 0.81 to 1.01). Similarly, the rate ratio for PD was 0.89 (95% CI 0.79 to 0.99). Adjusted rate ratios for other individual basal ganglia and movement disorders were also not significantly increased or decreased. Further analyses of Parkinson’s disease by attained age, time period of follow up, geographical area of residency, and educational level revealed no significant differences between the welders and the general population. Rates for Parkinson’s disease among welders in shipyards, where exposures to welding fumes are higher, were also similar to the general population (aRR = 0.95; 95% CI 0.70 to 1.28).

Conclusion:This nationwide record linkage study offers no support for a relation between welding and Parkinson’s disease or any other specific basal ganglia and movement disorders.
ON PHYSICAL PROPERTIES OF CYLINDRICALLY SYMMETRIC SELF-SIMILAR SOLUTIONS
Authors: SHARIF M. , AZIZ SEHAR
Published: January 2006

This paper is devoted to discuss some of the features of self-similar solutions of the first kind. We consider the cylindrically symmetric solutions with different homotheties. We are interested in evaluating the quantities acceleration, rotation, expansion, shear, shear invariant and expansion rate. These kinematical quantities are discussed both in comoving as well as in noncomoving coordinates (only in radial direction). Finally, we would discuss the singularity feature of these solutions. It is expected that these properties would help in exploring some interesting features of the self-similar solutions.
Role of ATP in DNA synthesis of renal proximal tubule cells: involvement of calcium, MAPKs, and CDKs
Authors: Lee Yun Jung , Han Ho Jae
Published: January 2006

Although ATP has been shown to act as a modulator in various kidney functions, its effect on renal proximal tubule cell (PTC) proliferation has not been elucidated. This study investigated the effect of ATP on cell proliferation and the effect of its related signal pathways on primary cultured PTCs. Treatment with >10−5M ATP for 1 h stimulated incorporation of thymidine and bromodeoxyuridine. ATP (10−4M)-induced stimulation of thymidine incorporation was blocked by suramin (a P2X and P2Y receptor antagonist), reactive blue 2 (a P2Y receptor antagonist), MRS-2159 (a P2X1receptor antagonist), and MRS-2179 (a P2Y1receptor antagonist). ATP increased intracellular Ca2+concentration, which was blocked by suramin, methoxyverapamil, and EGTA. ATP-induced stimulation of cell proliferation was also blocked by EGTA (an extracellular Ca2+chelator), methoxyverapamil (a Ca2+antagonist), and nifedipine (an L-type Ca2+channel blocker), suggesting a role for Ca2+influx. ATP-induced phosphorylation of p38 and p44/42 MAPKs was blocked by nifedipine. ATP increased expression levels of cyclin-dependent kinase (CDK)-2, CDK-4, and cyclin E, which were blocked by suramin, reactive blue 2, MRS-2179, MRS-2159, and nifedipine. However, ATP decreased expression levels of p21WAF1/Cip1and p27kip1. ATP-induced stimulation of thymidine incorporation and increase of CDK-2 and CDK-4 expression were blocked by SB-203580 (a p38 MAPK inhibitor) and PD-98059 (an MEK inhibitor), but not by SP-600125 (a JNK inhibitor). In conclusion, ATP stimulates proliferation by increasing intracellular Ca2+concentration and activating p38, p44/42 MAPKs, and CDKs in PTCs.
Relationship Between Physiological Response Type (RA and SA) and Vibrissal Receptive Field of Neurons Within the Rat Trigeminal Ganglion
Authors: Leiser Steven C. , Moxon Karen A.
Published: January 2006

Cells within the trigeminal ganglion (Vg) encode all the information necessary for the rat to differentiate tactile stimuli, yet it is the least-studied component in the rodent trigeminal somatosensory system. For example, extensive anatomical and electrophysiological investigations have shown clear somatotopic organization in the higher levels of this system, including VPM thalamus and SI cortex, yet whether this conserved schemata exists in the Vg is unknown. Moreover although there is recent interest in recording from vibrissae-responsive cells in the Vg, it is surprising to note that the locations of these cells have not even been clearly demarcated. To address this, we recorded extracellularly from 350 sensory-responsive Vg neurons in 35 Long-Evans rats. First, we determined three-dimensional locations of these cells and found a finer detail of somatotopy than previously reported. Cells innervating dorsal facial features, even within the whisker region, were more dorsal than midline and ventral features. We also show more cells with caudal than rostral whisker receptive fields (RF), similar to that found in VPM and SI. Next, for each vibrissal cell we determined its response type classified as either rapidly (RA) or slowly (SA) adapting. We examined the relationship between vibrissal RF and response type and demonstrate similar proportions of RA and SA cells responding to any whisker. These results suggest that if RA and SA cells encode distinct features of stimuli, as previously suggested, then at the basic physiological level each whisker has similar abilities to encode for such features.
Gene expression in ductus arteriosus and aorta: comparison of birth and oxygen effects
Authors: Costa Mario , Barogi Silvia , Socci Nicholas D. , Angeloni Debora , Maffei Margherita , Baragatti Barbara , Chiellini Chiara , Grasso Emanuela , Coceani Flavio
Published: January 2006

Ductus arteriosus (DA) closure is initiated by oxygen rise postnatally and progresses in two, functional-to-permanent, stages. Here, using GeneChip Arrays in rats (normoxic and hyperoxic fetus, normoxic newborn), we examined whether oxygen alone duplicates the birth process in affecting DA genes. In addition, by comparing DA with aorta (Ao), we identified features in postnatal gene profile marking transitional adjustments in a closing (DA) vs. a persistent (Ao) vessel. We found changes in neonatal DA denoting enhanced formation and action of the constrictor endothelin-1 (ET-1). Likewise, ANG II type 1 receptor was upregulated, and the compound was a constrictor. Conversely, relaxant PGE2became less effective. Among agents for functional closure, only ET-1 was affected similarly by oxygen and birth. Coincidentally, neonatal DA showed enhanced contractile drive with upregulation of Rho-Rho kinase and calcium signaling along with downregulation of contractile proteins. The latter effect was shared by oxygen. Changes denoting active remodeling were also seen in neonatal but not hyperoxic fetal DA. Ao, unlike DA, exhibited postnatal variations in noradrenergic, purinergic, and PGI2systems with opposing effects on vasomotion. Contraction and remodeling processes were also less affected by birth, whereas lipid and glucose metabolism were upregulated. We conclude that several agents, including ANG II as novel effector, promote functional closure of DA, but only ET-1 is causally coupled with oxygen. Oxygen has no role in processes for permanent closure. Functional closure is associated with downregulation of contractile apparatus, and this may render neonatal DA less amenable to tone manipulation. Conceivably, activation of metabolism in neonatal Ao is a distinguishing feature for transitional adaptations in the permanent vasculature.
The Possible Role of EWS-Fli1 in Evasion of Senescence in Ewing Family Tumors
Authors: Matsunobu Tomoya , Tanaka Kazuhiro , Nakamura Tomoyuki , Nakatani Fumihiko , Sakimura Riku , Hanada Masuo , Li Xu , Okada Takamitsu , Oda Yoshinao , Tsuneyoshi Masazumi , Iwamoto Yukihide
Published: January 2006

The chromosomal translocation t(11;22) yields the EWS-Fli1 fusion gene and is associated with oncogenesis of Ewing family tumors (EFT). In this study, using the RNA interference method, we show that EWS-Fli1–targeting small interfering RNAs (siRNA) depleted EWS-Fli1 protein and caused growth inhibition in EFT cells with the accumulation of p27 protein and the down-regulation of Skp2 protein in dose-dependent, time-dependent, and sequence-specific manners. Depletion of EWS-Fli1 subacutely elicited a senescence-like phenotype, but not apoptosis, in EFT cells. Furthermore, not only the knockdown of p27, but also the forced expression of Skp2, reduced the expression levels of p27 protein and partially rescued senescence-like phenotype caused by EWS-Fli1–targeting siRNAs. The accumulation of p27 protein in EWS-Fli1–depleted cells inhibited cdk2 kinase activity and was related to the stability of p27 protein, which resulted from a decrease in Skp2 protein. Immunohistochemical analysis of p27 and Skp2 proteins in EFT samples revealed that there was an inverse relationship between the expression profiles of p27 and Skp2 proteins. These findings indicate an important role of EWS-Fli1 in the prevention of senescence, leading to the unlimited growth and oncogenesis of EFT cells through a decrease in the stability of p27 protein due to increased action of Skp2-mediated 26S proteasome degradation. (Cancer Res 2006; 66(2): 803-11)
Helicobacter Infection Is Required for Inflammation and Colon Cancer in Smad3-Deficient Mice
Authors: Maggio-Price Lillian , Treuting Piper , Zeng Weiping , Tsang Mark , Bielefeldt-Ohmann Helle , Iritani Brian M.
Published: January 2006

Accumulating evidence suggests that intestinal microbial organisms may play an important role in triggering and sustaining inflammation in individuals afflicted with inflammatory bowel disease (IBD). Moreover, individuals with IBD are at increased risk for developing colorectal cancer, suggesting that chronic inflammation may initiate genetic or epigenetic changes associated with cancer development. We tested the hypothesis that bacteria may contribute to the development of colon cancer by synergizing with defective transforming growth factor-β (TGF-β) signaling, a pathway commonly mutated in human colon cancer. Although others have reported that mice deficient in the TGF-β signaling molecule SMAD3 develop colon cancer, we found that SMAD3-deficient mice maintained free of the Gram-negative enterohepatic bacteria Helicobacter spp. for up to 9 months do not develop colon cancer. Furthermore, infection of SMAD3−/− mice with Helicobacter triggers colon cancer in 50% to 66% of the animals. Using real-time PCR, we found that Helicobacter organisms concentrate in the cecum, the preferred site of tumor development. Mucinous adenocarcinomas develop 5 to 30 weeks after infection and are preceded by an early inflammatory phase, consisting of increased proliferation of epithelial cells; increased numbers of cyclooxygenase-2–positive cells, CD4+ T cells, macrophages; and increased MHC class II expression. Colonic tissue revealed increased transcripts for the oncogene c-myc and the proinflammatory cytokines interleukin-1α (IL-1α), IL-1β, IL-6, IFN-γ, and tumor necrosis factor-α, some of which have been implicated in colon cancer. These results suggest that bacteria may be important in triggering colorectal cancer, notably in the context of gene mutations in the TGF-β signaling pathway, one of the most commonly affected cellular pathways in colorectal cancer in humans. (Cancer Res 2006; 66(2): 828-38)
Increased Expression of Osteopontin Contributes to the Progression of Prostate Cancer
Authors: Khodavirdi Ani C. , Song Zhigang , Yang Shangxin , Zhong Chen , Wang Shunyou , Wu Hong , Pritchard Colin , Nelson Peter S. , Roy-Burman Pradip
Published: January 2006

Osteopontin is a secreted glycosylated phosphoprotein known to be involved in numerous physiologic functions and associated with the late stages of various cancers. We used preneoplastic and neoplastic mouse models of prostate cancer to determine the onset of elevated expression of osteopontin in the development of this disease. Osteopontin alterations occurred early in the disease with dysregulated expression observed in lesions of low-grade prostatic intraepithelial neoplasia (PIN). Over time, osteopontin expressing dysplastic cells seemed to increase in number in high-grade PIN and increased further in adenocarcinoma, and in metastasis, almost all of the cancer cells immunohistochemically stained positive for osteopontin overexpression. We examined the biological properties of human prostate cancer cell lines LNCaP and PC-3, in which osteopontin overexpression was achieved via lentiviral gene transduction. Evidence was obtained that osteopontin could contribute to a proliferative advantage in both cell types, although more significantly in LNCaP than PC-3. Osteopontin also influenced their in vitro invasive ability, and again, most strikingly in the weakly oncogenic LNCaP. Furthermore, excess osteopontin induced the LNCaP cells to acquire a strong intravasation potential in vivo in the chicken embryo chorioallantoic membrane assay for blood vessel penetration. These results establish a correlation between an increased gradient of osteopontin expression throughout the stages of murine prostate cancer, beginning from the preneoplastic lesions to distant metastases that suggests a proliferative and invasive advantages to those prostate tumor cells overexpressing osteopontin. Together, these findings support a strategy designed to target osteopontin in the context of prostate cancer therapy. (Cancer Res 2006; 66(2): 883-8)
Structural Changes of the Corpus Callosum in Mild Cognitive Impairment and Alzheimer’s Disease
Authors: Thomann Philipp A. , Wüstenberg Torsten , Pantel Johannes , Essig Marco , Schröder Johannes
Published: January 2006

Background: Although previous studies demonstrate significant atrophy of the corpus callosum (CC) in patients with Alzheimer’s disease (AD), CC alterations in mild cognitive impairment have not been investigated yet. Methods: 21 subjects with mild cognitive impairment, 10 with AD and 21 healthy controls were investigated using magnetic resonance imaging. In the mid-sagittal slice the CC was traced manually. Additionally, voxel-based morphometry (VBM) was performed. Results: The CC was significantly smaller in patients with AD compared to healthy controls in both manual tracing and VBM. The atrophy was prominent in rostral parts of the CC. In subjects with mild cognitive impairment, the two rostral CC segments were smaller compared to controls when manually traced. In contrast, VBM revealed no significant difference between subjects with mild cognitive impairment and controls. Conclusion: Manual tracing was more sensitive in detecting discrete structural CC changes than VBM. Alterations of the CC in mild cognitive impairment rank in between normal aging and AD, supporting the hypothesis that mild cognitive impairment most often represents a preclinical stage of AD.
Therapeutic neovascularization by transplantation of mobilized peripheral blood mononuclear cells for limb ischemia
Authors: Li Shu , Zhou Bin , Han Zhong
Published: January 2006

Autolougous transplantation of granulocyte colony-stimulating factor (G-CSF)-mobilized human peripheral blood mononuclear cells (PBMNCs) improves limb ischemia in patients with arteriosclerosis obliterans of lower extremities and with diabetic foot. However, the mechanism of action of PBMNCs remains elusive. Here, we studied comparatively the effects of the G-CSF-mobilized PBMNCs and CD34-depleted G-CSF-mobilized PBMNCs in an ischemia model of athymic nude mice. Fluorescence-labeled human PBMNCs [1×106] were intramuscularly injected into the unilateral ischemic hindlimbs of mice. Laser Doppler imaging analysis revealed a significantly augmented blood perfusion at day 7, 14 and 28 after operation. The capillary density was also markedly increased and the rate of limb loss was significantly reduced in cell-transplanted groups when compared with those in PBS group. In comparison with G-CSF-mobilized PBMNCs, the therapeutic efficiency of G-CSF-mobilized PBMNCs deprived of CD34+ cells was impaired. Transplanted cells were found to accumulate around arterioles and scatter in capillary networks. Incorporation of transplanted cells into new capillaries was observed in the G-CSF-mobilized PBMNCs group, but was not detected in the group deprived of CD34+ cells. There was an elevated expression of VEGF in ischemic tissue. Colocalization of VEGF and transplanted mononuclear cells within adductor tissue was demonstrated. These findings indicate that G-CSF-mobilized PBMNCs promote vascular growth not only by incorporating into vessel walls but also by supplying angiogenic factors. The depletion of CD34+ cells attenuated the therapeutic efficiency of G-CSF-mobilized PBMNCs in response to ischemia-induced neovascularization.
Pre-treatment with clopidogrel and postprocedure troponin elevation after elective percutaneous coronary intervention
Authors: Nienhuis Mark , Miedema Kor , Suryapranata Harry , de Boer Menko-Jan , Dambrink Jan-Henk , Hoorntje Jan , van ’t Hof Arnoud , Gosselink Marcel , Zijlstra Felix , Ottervanger Jan
Published: January 2006

Elevated troponin after elective percutaneous coronary intervention (PCI) has been associated with a worse prognosis. Pretreatment with clopidogrel may be beneficial in patients undergoing PCI. Therefore, a prospective observational study was conducted to address the potential role of clopidogrel in reducing troponin release after elective PCI. TroponinT was measured 12 hours after elective PCI in 656 patients without elevated troponin before PCI. To assess the independent association between pre-treatment with clopidogrel and increased troponin, multivariate analyses were performed. Mean age of the 656 patients was 63.5 years (SD 10.2), 194 patients (30%) were female and 114 patients (17.4%) had diabetes. In 217 patients (33%) troponin was increased after PCI. Of the 330 patients who were not pre-treated with clopidogrel, 118 patients (34%) had increased troponin after the PCI compared to 99 patients (30%) of the 326 patients who were treated with clopidogrel longer than 24 hours before the procedure (p=0.14). Stratified analyses showed that patients with older age (p=0.03), previous PCI (p=0.013), angina CCS 4 (p=0.03) and multivessel disease (p=0.04) had a significantly lower risk of troponin increase after pre-treatment with clopidogrel compared to patients without pre-treatment. After adjusting for differences in the other variables, patients who were pre-treated with clopidogrel had a significant lower risk of post-PCI increase of troponinT (odds ratio 0.69, 95% confidence interval 0.49–0.99). Pre-treatment with clopidogrel is associated with a significantly lower incidence of increased troponin after elective PCI. Combined with results of other studies, pre-treatment should be advised in patients waiting for elective PCI.
Antiviral therapy decreases GpIIb/IIIa activation of platelets in patients with chronic hepatitis C
Authors: Sieghart Wolfgang , Homoncik Monika , Jilma Bernd , Formann Elisabeth , Ferenci Peter , Gangl Alfred , Peck-Radosavljevic Markus
Published: January 2006

Interferon alpha (IFN-α) is used to treat haematological and solid malignancies and is the gold standard therapy for chronic hepatitisC infection in combination with ribavirin. It has a well known platelet lowering effect and was recently shown to impair platelet aggregation in the presence of various agonists and has been accused to increase patients’ bleeding risk during IFN-α therapy. Thus, we hypothesised that antiviral treatment decreases GpIIb/IIIa activation and affects global platelet function. In a prospective clinical trial, we examined the effects of combination therapy with pegylated IFN-α 2a (PegIFN-α 2a) and ribavirin on platelet GpIIb/IIIa activation and platelet secretion in 20 patients with chronic hepatitis C at week 2, 4, 8 and 12 after the beginning of therapy. In addition, we determined global platelet function (CEPI-CT) with the PFA-100 and vWF-Ag levels. Antiviral therapy significantly decreased GpIIb/IIIa activation in a time dependent manner, whereas markers of platelet secretion (P-selectin, β-thromboglobulin) remained unchanged. Despite a marked elevation of vWF-Ag levels, CEPI-CT did not change compared to baseline levels. Antiviral therapy significantly decreases GpIIb/IIIa activation in patients with chronic hepatitis C, while vWG-Antigen levels are markedly increased and α-granule secretion is not affected. This does not result in an alteration of global platelet function as assessed by the PFA-100, because elevated vWF-Antigen levels might compensate for the acquired defect.
Soy Protein, Isoflavones, and Cardiovascular Health
Authors: Sacks Frank M. , Lichtenstein Alice , Van Horn Linda , Harris William , Kris-Etherton Penny , Winston Mary
Published: January 2006

Soy protein and isoflavones (phytoestrogens) have gained considerable attention for their potential role in improving risk factors for cardiovascular disease. This scientific advisory assesses the more recent work published on soy protein and its component isoflavones. In the majority of 22 randomized trials, isolated soy protein with isoflavones, as compared with milk or other proteins, decreased LDL cholesterol concentrations; the average effect was &3%. This reduction is very small relative to the large amount of soy protein tested in these studies, averaging 50 g, about half the usual total daily protein intake. No significant effects on HDL cholesterol, triglycerides, lipoprotein(a), or blood pressure were evident. Among 19 studies of soy isoflavones, the average effect on LDL cholesterol and other lipid risk factors was nil. Soy protein and isoflavones have not been shown to lessen vasomotor symptoms of menopause, and results are mixed with regard to soy’s ability to slow postmenopausal bone loss. The efficacy and safety of soy isoflavones for preventing or treating cancer of the breast, endometrium, and prostate are not established; evidence from clinical trials is meager and cautionary with regard to a possible adverse effect. For this reason, use of isoflavone supplements in food or pills is not recommended. Thus, earlier research indicating that soy protein has clinically important favorable effects as compared with other proteins has not been confirmed. In contrast, many soy products should be beneficial to cardiovascular and overall health because of their high content of polyunsaturated fats, fiber, vitamins, and minerals and low content of saturated fat.
Suppression of Delamination at Ply Drops in Tapered Composites by Ply Chamfering
Authors: Khan B. , Potter K. , Wisnom M. R.
Published: January 2006

The design of structures is often optimized by gradually decreasing the thickness as the load carrying requirement on the components decreases. Such structures in composites are made of tapered laminates involving dropping of plies. However, these structures are often prone to early delamination initiation, which leads to premature failure of the component and therefore limits its useful life. In the past, many routes to circumvent this problem have been evolved, such as the use of adhesive film layers or interleaving the dropped plies between continuous ones. In this work, a novel technique of ply edge chamfering has been developed and employed in the specimen fabrication. Comparisons have been drawn between similarly configured specimens, with and without chamfered ply drops. Static and fatigue test results have shown remarkable improvements, both in terms of complete suppression of delamination around ply drops and in realizing 14.5–77.6% higher strength levels in tapered composite test coupons. The experimental data along with their comparative cases are presented.
Modeling Inelastic Matrix Crack Tip Deformation in a Double Cantilever Beam Specimen
Authors: Gregory Jeremy R. , Spearing S. Mark
Published: January 2006

A finite element model is created to investigate the contribution of inelastic matrix deformation at the crack tip to the composite toughness in a double cantilever beam specimen. The constituent properties are explicitly incorporated into the analysis using a global–local model and discrete fiber and matrix layers in the local model. The results indicate that there is little difference between the global and local J-integrals for matrices that do not exhibit pressure-dependent plastic deformation. Plastic deformation occurs in matrix layers away from the crack tip, but the majority of the deformation in terms of strain intensity occurs in the resinrich region at the crack tip. This localized intensity causes the crack tip strains and plastic energy dissipation levels to be much higher in crack tips that are highly constrained by the layer of fibers, even though plastic volumes are lower. The results shed new light on previous explanations for the difference between ductile matrix and composite toughness and the thickness effect observed in adhesive bonds using ductile adhesives.
Experimental Investigation of Progressive Damage and the Effect of Layup in Notched Tensile Tests
Authors: Hallett Stephen R. , Wisnom Michael R.
Published: January 2006

The presence of subcritical damage in notched composites significantly affects the ultimate failure mode and strength. This article presents a detailed study of four different layups of E-glass/913 tested using a double-edge-notched specimen loaded in tension. For each layup three different in-plane dimensions are tested. Results are presented in terms of failure mode, strength, and subcritical damage development. Subcritical damage development is consistent between the layups and between scaled specimens of a single layup. Ultimate failure, however, shows some variations both with layup and size and this is examined in some detail. The trend of decreasing strength with increasing specimen size is observed for all cases except those where there is a change in failure mode between different size tests. The strengths are compared with predictions from two analytical techniques, which show some ability to achieve correlation across a subset of the test data. Correlation is not possible where variations in failure mode occur for a single layup.
C-Shape Specimen for Tensile Radial Strength of Thick, Filament-wound Rings
Authors: Sharma Ambuj , Bakis Charles E.
Published: January 2006

The objective of this investigation is to evaluate a new method of testing thick, C-shaped rings for determining the radial tensile strength of thick, filament-wound composite structures such as flywheel rotors. The proposed method of loading C-rings with a hydraulic jack is simpler than previously used loading methods and is shown to be quite tolerant of eccentricity of the jack. It is shown by sectioning a C-ring that residual stresses in the specimen are negligible. Based on a detailed stress analysis and post-failure inspections of appropriately dimensioned specimens, it is concluded that failure is caused by radial tensile stress at a single critical location in the specimen. The radial tensile strengths of four candidate flywheel rotor materials measured with C-rings were generally less than strengths measured with flexure specimens. The simplicity of specimen preparation and testing by the proposed method, in conjunction with promising early results, suggests that the C-ring test method is suitable for widespread use and possible standardization.
Effect of Nanoparticles and Ion Implantation on the Electromagnetic Shielding of Glass–Epoxy Composites
Authors: Jung Woo-Kyun , Ahn Sung-Hoon , Won Myung-Shik
Published: January 2006

The research on electromagnetic (EM) shielding has been advanced for various applications. Recently, researchers have been interested in nano-sized particles to modify electromagnetic properties of a base material. In this research, glass fiber–epoxy–nanoparticle composites (GFR nanocomposites) are fabricated using four types of nanoparticles, and their properties in electromagnetic shielding are compared. Carbon black (CB), multiwalled carbon nanotube (MWCNT), silver nanoflake (SNF), and silver nanopowder (SNP) are used as the added particles. For the visual observation of the nanocomposites, scanning electron microscope (SEM) and transmission electron microscope (TEM) are used. The characteristics of EM shielding of the composites are measured using HP8719ES Sparameter Vector Network Analyzer System for the frequency range between 8 and 12GHz. Composites using MWCNT and CB show outstanding shielding effect of 17 and 43 dB, respectively, but silver nanoparticles do not show significant EM shielding. In addition, change of EM shielding characteristics by the ion implantation process is observed. After ion implantation, the EM shielding of the composites containing silver is increased in the frequency range.
In Search of Generative Results: A New Generation of Programmes to Develop Work Organization
Authors: Alasoini Tuomo
Published: January 2006

This article examines means to improve the ability of work organization development programmes to create and disseminate good practices. The article states that there is a growing need for strategies that understand good practices more as generative ideas than ‘ready-made’ objects, and in which the focus of attention is on the creation of interactive contexts between various players already at the project planning and implementation stage. The ‘modules’ of the Norwegian Enterprise Development 2000 Programme (1994–2001) and the ‘network projects’ and ‘learning networks’ of the Finnish Workplace Development Programme (1996–2009) are used as examples of the principles of the new strategy in practice.
Entrenched Elitism in Trade Unions in Poland and Romania: An Explanation for the Lack of Union Strength and Success?
Authors: Korkut Umut
Published: January 2006

This article argues that democratic decision-making improves trade union strength and success during policy-making. Elitism and lack of democracy, on the other hand, diminish unions' strength. Elitism, in this respect, remains entrenched in trade union structures during internal decision-making. The author's argument is twofold: both the ability of trade union leaders to develop links with the rank-and-file and reduce hierarchy during internal decision-making influence the strength of organizations. Both factors help carry the spontaneous and local demands of union members onto the national agenda. This article assigns a crucial role to unions and interest groups in providing a system of interest representation sensitive to interests that might go unacknowledged in a system whose only devices of representation were political parties and representatives with territorial constituencies. However, this article does not idealize groups but rather questions their ability to represent the interests of their members. The author tests the plausibility of these hypotheses with data from interviews with trade union confederation and federation representatives from Romania and Poland. This article concludes that organizational democracy positively affects union success.
Striving for Control: Democracy and Oligarchy at a Mexican Cooperative
Authors: Hernandez Sarah
Published: January 2006

This article contributes to the analysis of cooperativism, showing that the cooperative workplace is neither fully democratic nor oligarchic, but rather is the site of contestation between these two tendencies. Through a case study of a large industrial cooperative in Mexico City, the author shows how the interaction between the organizational structure, participatory culture and individual behavior enhance both democracy and oligarchy. This is observed as workers attempt to maintain control over their representatives, partake in the politics of the process of nomination and participate at the general assembly. The author argues that a paradoxical perspective permits a better understanding of the complexities inherent in the dynamic and paradoxical character of cooperatives.
The Cognitive-Cultural Systems of the Research Laboratory
Authors: Nersessian Nancy J.
Published: January 2006

A central challenge for science studies researchers in developing accounts of knowledge construction in science and engineering is to integrate the cognitive, social, cultural, and material dimensions of practice. Within science studies there is a perceived divide between cognitive practices, on the one hand, and cultural practices, on the other. Any such divide, though at times analytically useful, is artificial. Producing scientific knowledge requires the kind of sophisticated cognition that only rich social, cultural, and material environments can enable. This paper aims to move in the direction of an integrative account of these dimensions of practice. It discusses model-based reasoning practices in biomedical engineering research laboratories construed as ‘evolving cognitive-cultural systems’.
‘What matters is what works’? How discourses of modernization have both silenced and limited debate on domiciliary care for older people
Authors: Scourfield Peter
Published: January 2006

Policy statements about the care of vulnerable older people repeatedly emphasize the desirability of keeping people at home. An enduring problem in implementing this strategy is the ongoing crisis within the quasi-market in domiciliary care. The government announced in 2004 that it wanted a new vision for adult social care. In such circumstances, it could be argued that, in order to achieve home care services that are stable, flexible and better placed to integrate more effectively with health agencies, local authorities should significantly expand in-house provision. Despite exhortations from ministers to think the unthinkable, such a proposal is actually ‘unsayable’. This article discusses how discourses of modernization exclude ideas that imply an expansion of directly provided social care. Such discourses have so much invested in the shedding of what it regards as outmoded ‘welfarist’ baggage, they are blind to proposals that could improve the lives of older, vulnerable citizens.