bluuebunny/crossref_metadata_2025 huggingface dataset:
Single and repeated immobilization stress differentially trigger induction and phosphorylation of several transcription factors and mitogen‐activated protein kinases in the rat locus coeruleus
Authors: Hebert Meleik A. , Serova Lidia I. , Sabban Esther L.
Published: August 2005

The locus coeruleus (LC) is a critical stress‐responsive location that mediates many of the responses to stress. We used immunoblotting and immunohistochemistry to investigate changes in induction and phosphorylation of several transcription factors and kinases in the LC that may mediate the stress‐triggered induction of tyrosine hydroxylase (TH) transcription. Rats were exposed to single or repeated immobilization stress (IMO) for brief (5 min), intermediate (30 min) or sustained (2 h) duration. Single IMO elicited rapid induction of c‐Fos and phosphorylation of cyclic AMP response element‐binding protein (CREB) without changing the expression of early growth response (Egr)1, Fos‐related antigen (Fra)‐2 or phosphorylated activating transcription factor‐2. Repeated IMO triggered increased phosphorylation and levels of CREB along with transient induction of c‐Fos and increased Fra‐2 expression. Several mitogen‐activated protein kinases were activated by repeated IMO, shown by increased phosphorylation of p38, c‐Jun N‐terminal kinase (JNK)1/2/3 and extracellular signal‐regulated kinase (ERK1/2). ERK1 was the major isoform expressed, and ERK2 the predominant isoform phosphorylated. Repeated IMO elicited hyperphosphorylation of ERK1/2 selectively in TH immunoreactive neurons, with substantial nuclear localization. These distinct alterations in transcriptional pathways following repeated compared with single stress may be involved in mediating long‐lasting neuronal remodeling and are implicated in the mechanisms by which acute beneficial responses to stress are converted into prolonged adaptive or maladaptive responses.
Isolation of 12 polymorphic microsatellite loci in the phytopathogenic fungus Alternaria brassicicola
Authors: AVENOT HERVÉ , DONGO ANITA , BATAILLÉ‐SIMONEAU NELLY , IACOMI‐ VASILESCU BÉATRICE , HAMON BRUNO , PELTIER DIDIER , SIMONEAU PHILIPPE
Published: August 2005

Twelve polymorphic microsatellite markers were isolated from the phytopathogenic fungus Alternaria brassicicola, the causal agent of black spot of crucifers. An enrichment protocol was used to isolate microsatellite loci, which were then analysed in a collection of 46 isolates sampled from seven different countries. The number of alleles detected in 12 loci ranged from two to 10 (mean 3.5). Investigation of cross‐species amplifications showed that the designed primers were specific to A. brassicicola.
An Early Palaeozoic HP/HT granulite–garnet peridotite association in the south Altyn Tagh, NW China:P–Thistory and U‐Pb geochronology
Authors: ZHANG J. X. , MATTINSON C. G. , MENG F. C. , WAN Y. S.
Published: August 2005

High‐pressure kyanite‐bearing felsic granulites in the Bashiwake area of the south Altyn Tagh (SAT) subduction–collision complex enclose mafic granulites and garnet peridotite‐hosted sapphirine‐bearing metabasites. The predominant felsic granulites are garnet + quartz + ternary feldspar (now perthite) rocks containing kyanite, plagioclase, biotite, rutile, spinel, corundum, and minor zircon and apatite. The quartz‐bearing mafic granulites contain a peak pressure assemblage of garnet + clinopyroxene + ternary feldspar (now mesoperthite) + quartz + rutile. The sapphirine‐bearing metabasites occur as mafic layers in garnet peridotite. Petrographical data suggest a peak assemblage of garnet + clinopyroxene + kyanite + rutile. Early kyanite is inferred from a symplectite of sapphirine + corundum + plagioclase ± spinel, interpreted to have formed during decompression. Garnet peridotite contains an assemblage of garnet + olivine + orthopyroxene + clinopyroxene. Thermobarometry indicates that all rock types experienced peakP–Tconditions of 18.5–27.3 kbar and 870–1050 °C. A medium–high pressure granulite facies overprint (780–820 °C, 9.5–12 kbar) is defined by the formation of secondary clinopyroxene ± orthopyroxene + plagioclase at the expense of garnet and early clinopyroxene in the mafic granulites, as well as by growth of spinel and plagioclase at the expense of garnet and kyanite in the felsic granulite. SHRIMP II zircon U‐Pb geochronology yields ages of 493 ± 7 Ma (mean of 11) from the felsic granulite, 497 ± 11 Ma (mean of 11) from sapphirine‐bearing metabasite and 501 ± 16 Ma (mean of 10) from garnet peridotite. Rounded zircon morphology, cathodoluminescence (CL) sector zoning, and inclusions of peak metamorphic minerals indicate these ages reflect HP/HT metamorphism. Similar ages determined for eclogites from the western segment of the SAT suggest that the same continental subduction/collision event may be responsible for HP metamorphism in both areas.
A counter‐clockwise P–T path for the Voltri Massif eclogites (Ligurian Alps, Italy)
Authors: VIGNAROLI G. , ROSSETTI F. , BOUYBAOUENE M. , MASSONNE H.‐J. , THEYE T. , FACCENNA C. , FUNICIELLO R.
Published: August 2005

Integrated petrological and structural investigations of eclogites from the eclogite zone of the Voltri Massif (Ligurian Alps) have been used to reconstruct a complete Alpine P–T deformation path from burial by subduction to subsequent exhumation. The early metamorphic evolution of the eclogites has been unravelled by correlating garnet zonation trends with the chemical variations in inclusions found in the different garnet domains. Garnet in massive eclogites displays typical growth zoning, whereas garnet in foliated eclogites shows rim‐ward resorption, likely related to re‐equilibration during retrogressive evolution. Garnet inclusions are distinctly different from core to rim, consisting primarily of Ca‐, Na/Ca‐amphibole, epidote, paragonite and talc in garnet cores and of clinopyroxene ± talc in the outer garnet domains. Quantitative thermobarometry on the inclusion assemblages in the garnet cores defines an initial greenschist‐to‐amphibolite facies metamorphic stage (M1 stage) at c. 450–500 °C and 5–8 kbar. Coexistence of omphacite + talc + katophorite inclusion assemblage in the outer garnet domains indicate c. 550 °C and 20 kbar, conditions which were considered as minimum P–T estimates for the M2 eclogitic stage. The early phase of retrograde reactions is polyphase and equilibrated under epidote–blueschist facies (M3 stage), characterized by the development of composite reaction textures (garnet necklaces and fluid‐assisted Na‐amphibole‐bearing symplectites) produced at the expense of the primary M2 garnet‐clinopyroxene assemblage. The blueschist retrogression is contemporaneous with the development of a penetrative deformation (D3) that resulted in a non‐coaxial fabric, with dominant top‐to‐the‐N sense of shear during rock exhumation. All of that is overprinted by a texturally late amphibolite/greenschist facies assemblages (M4 & M5 stages), which are not associated with a penetrative structural fabric. The combined P–T deformation data are consistent with an overall counter‐clockwise path, from the greenschist/amphibolite, through the eclogite, the blueschist to the greenschist facies. These new results provide insights into the dynamic evolution of the Tertiary oceanic subduction processes leading to the building up of the Alpine orogen and the mechanisms involved in the exhumation of its high‐pressure roots.
Roles for fluid and/or melt advection in forming high‐P mafic migmatites, Fiordland, New Zealand
Authors: CLARKE G. L. , DACZKO N. R. , KLEPEIS K. A. , RUSHMER T.
Published: August 2005

A series of striking migmatitic structures occur in rectilinear networks through western Fiordland, New Zealand, involving, for the most part, narrow anorthositic dykes that cut hornblende‐bearing orthogneiss. Adjacent to the dykes, host rocks show patchy, spatially restricted recrystallization and dehydration on a decimetre‐scale to garnet granulite. Although there is general agreement that the migration of silicate melt has formed at least parts of the structures, there is disagreement on the role of silicate melt in dehydrating the host rock. A variety of causal processes have been inferred, including metasomatism due to the ingress of a carbonic, mantle‐derived fluid; hornblende‐breakdown leading to water release and limited partial melting of host rocks; and dehydration induced by volatile scavenging by a migrating silicate melt. Variability in dyke assemblage, together with the correlation between dehydration structures and host rock silica content, are inconsistent with macroscopic metasomatism, and best match open system behaviour involving volatile scavenging by a migrating trondhjemitic liquid.
An in situ metatexite–diatexite transition in upper amphibolite facies rocks from Broken Hill, Australia
Authors: WHITE R. W. , POMROY N. E. , POWELL R.
Published: August 2005

Upper amphibolite facies felsic gneiss from Broken Hill records the metatexite to schlieren diatexite to massive diatexite transition in a single rock type over a scale of tens to hundreds of metres. The metatexites are characterized by centimetre‐scale segregation of melt into leucosomes to form stromatic migmatite. The schlieren diatexites are characterized by the disaggregation of the rocks and the development of schlieren migmatite. The massive diatexites represent a higher degree of disaggregation, lack schlieren and contain plagioclase and K‐feldspar phenocrysts. The transition from metatexite to schlieren diatexite and massive diatexite was heterogeneous with both disaggregation of the rock on a grain scale and disaggregation of the rock into centimetre‐ to metre‐scale rafts. As melt contents increased, the proportion of material disaggregated on a grain scale increased. The high proportion of melt needed to form diatexites at upper amphibolite facies conditions was the result of an influx of hydrous fluid at temperatures just above the solidus of the diatexites. Nearby metapelitic rocks, with a slightly higher solidus temperature, undergoing subsolidus muscovite breakdown are the likely source of the fluid. Continued heating during and after the influx of fluid led to melt contents of up to c. 60 mol.% in the massive diatexite. The metatexite zone probably involved little added fluid. Continued deformation during cooling and melt crystallization resulted in the extensive development of schlieren and late‐stage melt segregations and melt‐rich shear bands in the schlieren diatexite zone. The rocks of the massive diatexite zone lack these late‐stage segregations, consistent with the cessation of D2 deformation prior to them developing a crystal framework.
A Role for Stem Cell Biology in the Physiological and Pathological Aspects of Aging
Authors: Snyder Evan Y. , Loring Jeanne F.
Published: August 2005

The stem cell is an essential component of a developmental phenomenon—one of the key components of a program fundamental to organogenesis and the maintenance of homeostasis throughout life. The stem cell confers plasticity to the process. Because aging is part of the developmental arc, an understanding of the stem cell is essential to understanding aging and some of the degenerative conditions that accompany it. Because stem cells may be isolated and manipulated ex vivo and then reimplanted into organs, they may serve a variety of functions. They have the capability of migrating long distances and targeting pathological conditions, of expressing therapeutic genes and responding to cues that shift their differentiation toward deficient lineages. Therefore, stem cells may be used for cell replacement, for therapeutic interventions, and potentially to modify aging.
Economic and Policy Implications of Improving Longevity
Authors: Vladeck Bruce C.
Published: August 2005

With all the rhetoric surrounding the impending “entitlement crisis” produced by the “graying of America,” there has been surprisingly little serious analysis of the social and economic implications of increased longevity and the doubling of the number of elderly people that will occur in this country over the next 30 years. This article identifies five critical areas in which the effect of demographic change will be significant. First, patterns of work life and labor‐force participation will almost inevitably change. Second, government expenditures now financed largely by payroll and federal income taxes will increase, whereas those financed by state and local property taxes will fall, at least proportionately. Third, the post‐World War II pattern of suburbanized, automobile‐dependent communities will pose special challenges to serving an aging population, and new adaptations will need to be developed. Fourth, intrafamily caregiving patterns will necessarily change. Fifth, the level of disability and dependence of older people, for which the rate of change is inherently unpredictable, will have a major effect on all these and other phenomena. Whether one views the net effect of all these changes as a positive or a negative, it is necessary to begin thinking a lot harder and more systematically about all of them.
Extraordinary Longevity: Individual and Societal Issues
Authors: Louria Donald B.
Published: August 2005

The likelihood of substantial increases in average life spans and the potential for profound longevity increases (to 100, 110, or 120 years on average) raises a host of societal issues. These include huge increases in the number of old and very old persons, the likelihood of a massive increase in health expenditures for the population aged 65 and older, the potential for outliving financial resources, challenges to the viability of Social Security and pensions, concerns about quality of life, and possible intergenerational antagonisms. If marked increases occur in average life spans worldwide, several billions could be added to world population at eventual stability, and that could become a sustainability issue.

To prepare for what is likely to be our demographic future requires a major shift in thinking about this type of complex issue; we must change from a simple linear to a much broader systems approach. Changes in retirement age, strengthening (but then replacing) the Social Security system, retaining older persons in the labor force, mandating retirement savings during working years, and many other actions must be considered in a debate that should start now about life span increase and the future; if we dawdle, we risk the consequences of being unprepared for the dramatic demographic changes that are likely to occur in the coming decades.
Nation as Partnership: Law, “Race,” and Gender in Aotearoa New Zealand's Treaty Settlements
Authors: Seuffert Nan
Published: August 2005

This article uses postcolonial theory to analyze the dynamic convergence of two significant international trends in Aotearoa New Zealand: the movement for reparations for historical colonial injustices, and the economic reform process known as “structural adjustment,” or Reaganomics in the United States, which was intended to produce a competitive nation of individual entrepreneurs. It argues that analysis of the interrelationships of law, “race,” gender, and nation in this convergence illuminates the reproduction and reshaping of colonial tropes, or historical racial configurations produced through colonization, in these current trends. In Aotearoa New Zealand, claims by indigenous Maori activists for self-determination and redress of historical injustices spurred the emergence of alternative imagined communities with the potential to transform the nation. These alternative visions for the nation were shaped and limited by the economic law and policy reform of structural adjustment, producing a new official nationalism of partnership, implemented in settlements of breaches of the Treaty of Waitangi 1840. These partnerships resulted in a new individual identity of Maori men as entrepreneurs in a competitive nation. It produced a symbolic alliance of men across race that silenced and erased Maori activists' demands, and the leadership of Maori women, at the national level. The high profile partnerships, the erasure of Maori women, and relentless media attention to claims of sexism in Maori culture reproduced colonial tropes with images of the “progress” of the partnerships “saving” brown women from the sexism of brown men and “traditional” cultures. In this complex process the settlements were rational exercises of agency by the new Maori entrepreneurs with the goal of achieving economic autonomy, and worked to silence and erase the leadership of Maori women at the national level, even while women continued to be recognized as leaders at the local and regional levels. This analysis suggests that realization of the transformative potential of claims for redress of historical racial injustices requires attention to the repetition of raced and gendered dynamics of imagined communities that shape and limit that potential.
A Dutiful Voice: Justice in the Distribution of Jury Service
Authors: Rose Mary R.
Published: August 2005

Jury service in the United States is both compulsory and yet distributed to some but not others in a nonsystematic way. Concerns about unfairness in this distribution system have led to legal changes; however, there is still little empirical information on how jurors view the jury selection process. This study considers jury selection in terms of participants' perceptions of procedural and distributive justice. I argue that justice in this setting is related to areas of conflict between the decision maker and the prospective jurors, especially over privacy protection, despite strong rhetoric that jurors minimize their own preferences and rights in this setting. Data from interviews of 194 formerly excused and selected jurors support this contention.
Inhibitory effects of a super pulsed carbon dioxide laser at low energy density on periodontopathic bacteria and lipopolysaccharide in vitro
Authors: Kojima Taro , Shimada Koichi , Iwasaki Hiroyasu , Ito Koichi
Published: August 2005

Objective and background:  Previous studies have described the effect of irradiation by a carbon dioxide (CO2) laser at high energy density on oral bacteria, and various side‐effects have also been observed. However, no published studies have examined the effect of irradiation by a CO2 laser at low energy density on oral bacteria. The purpose of this study was to investigate the effects of super pulsed CO2 laser irradiation on periodontopathic bacteria and lipopolysaccharide (LPS).

Methods:  Bacterial suspensions of two species of periodontopathic bacteria received laser irradiation at energy densities of 0–12.5 J/cm2. The suspensions were then spread over agar plates and incubated anaerobically. The bactericidal effects were evaluated based on colony formation. Samples of LPS were laser‐irradiated at energy densities of 0–12.5 J/cm2. The biological activity was measured, and LPS was analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE).

Results:  The irradiation at low energy densities of 7.5 and 12.5 J/cm2 killed more than 99.9 and 99.999% of Porphyromonas gingivalis and more than 99% of Actinobacillus actinomycetemcomitans was sterilized by the irradiation at 7.5 J/cm2. LPS biological activity was significantly decreased by laser irradiation at energy densities of more than 7.5 J/cm2 (p < 0.05), and the components of LPS analyzed by SDS–PAGE was diminished non‐specifically.

Conclusion:  The results indicate that CO2 laser irradiation at low power is capable of bactericidal effect on periodontopathic bacteria and decreasing LPS activity.
Immunohistochemical evaluation of intermediate filament proteins in squamous papilloma and oral verrucous carcinoma
Authors: Oliveira MC , Silveira EJD , Godoy GP , Amorim RFB , Costa ALL , Queiroz LMG
Published: August 2005

Objective:  Cytokeratins (CKs) are the intermediate filament proteins of the epithelium cells, which have become important markers of normal and abnormal cell differentiation. The goal of the present study was to investigate the expression pattern of CK 10, 13, 14 and 16 in oral verrucous carcinoma (OVC) and oral squamous papilloma (OSP).

Material and methods:  Formalin‐fixed paraffin‐embedded sections from eight cases of each lesion were assessed. Immunohistochemistry was carried out using streptoavidin‐biotin complex method.

Results:  In OVC, CK 10 was expressed in suprabasal to superficial layers whereas in OSP mainly in superficial layer. CK 13 was detected in prickle and superficial cells in most cases of OVC and in suprabasal to superficial cells of OSP. All the cell layers of OVC reacted positively for CK 14 while basal and suprabasal layers of OSP were more pronounced for CK 14. Finally, CK 16 was observed in suprabasal to superficial layer in OVC and the majority cases in OSP showed only superficial reactive cells.

Conclusions:  CK 10, 13, 14 and 16 immunohistochemical profile emphasis the biological behavior of the studied lesions and confirm the use of these proteins as markers of differentiation.
Oral health in patients on inhaled corticosteroid treatment
Authors: Komerik N , Akkaya A , Yıldız M , Buyukkaplan US , Kuru L
Published: August 2005

Objective:  The aim of this study was to investigate the effects of long‐term inhaled corticosteroids on bone mineral density (BMD) of the mandible in relation with the tooth loss.

Design:  Cross sectional analytic study.

Subjects and methods:  Patients (n = 30) with chronic obstructive pulmonary disease under inhaled corticosteroid therapy for at least 1 year were compared with sex‐ and age‐matched healthy controls (n = 30). BMD of the mandible was measured by dual‐energy X‐ray absorptiometry. The clinical examination included recording the number of teeth present together with periodontal condition. Levels of serum osteocalcin, alkaline phosphatase, calcium, phosphorus and cortisol were also assessed.

Results:  BMD of the mandible in patients on corticosteroid treatment was significantly lower than that in the control group (P = 0.001). Patients under treatment had more missing teeth than the control group but the difference did not reach statistical significance. The two groups exhibited similar clinical parameters of periodontal condition. Significantly lower levels of osteocalcin (P < 0.0001), calcium (P = 0.004) and cortisol (P = 0.03) were observed in the patients on corticosteroid treatment.

Conclusion:  Long‐term use of inhaled corticosteroids may impair bone metabolism and lead to a marked decrease in the mandibular BMD.
Fluconazole and/or hexetidine for management of oral candidiasis associated with denture‐induced stomatitis
Authors: Koray M , Ak G , Kurklu E , Issever H , Tanyeri H , Kulekci G , Guc U
Published: August 2005

Objective:  The aim of the present study was to compare the influence of fluconazole capsules and/or hexetidine mouthrinses for the management of oral candidiasis associated with denture stomatitis.

Design relevant:  Sixty‐one patients (ages 43–76 years, mean: 61) admitted to the Department of Oral Surgery and Medicine and diagnosed as suffering from oral candidiasis associated with denture stomatitis by microbiological examination were involved.

Materials and methods:  Patients in group 1 (n = 21) were given only fluconazole capsules (Zolax 50 mg once a day), those in group 2 (n = 18) were given only hexetidine mouthrinses (Heksoral 0.1%, twice daily), whereas those in group 3 (n = 22) were given both fluconazole capsules and hexetidine mouthrinses for 14 days. The yeast colonies of the saliva samples were counted and calculated as the number of colony forming units per milliliter. The presence of yeasts in the lesion and denture samples were evaluated as present/absent according to their growth on cultures. Candida albicans was identified by means of germ tube analysis.

Results:  Patients in groups 1, 2 and 3 had a statistically significant decrease in the amount of C. albicans in saliva, lesions and dentures after treatment, when compared with pretreatment results (P < 0.05). Candida albicans counts in saliva, lesion and denture after treatment detected no statistically significant difference when the three groups were compared.

Conclusion:  Of the three study groups, group 2, where hexetidine was the only medication prescribed, was found to be superior on account of fewer potential complications. We conclude that dentists should employ a more conservative intervention with oral mouthrinses rather than risk adverse effects and complications of systemic drugs for the management of oral candidiasis.
Clinicostatistical study of carotid calcification on panoramic radiographs
Authors: Tamura T , Inui M , Nakase M , Nakamura S , Okumura K , Tagawa T
Published: August 2005

Objective:  The purpose was to evaluate carotid calcifications on panoramic radiographs, and relate to risk factors for vascular diseases.

Method:  Between 1997 and 2001, 2568 radiographs were retrospectively collected from new patients at Mie University Hospital whose ages ranged from 50 to 70 years. The mean age of the subjects was 62.2 years (men 61.9 years, women 62.3 years). Medical and social data were collected from case notes, and body weight, height, and age of menopause confirmed by telephone interviews.

Result:  About 106 carotid calcifications were found on the panoramic radiographs of 26 males and 80 females. The ratio of males to females was 1:3.07. The subjects with carotid calcifications had medical histories that included hypertension (27.6%), obesity (21.1%), hyperlipidemia (14.5%), and cardiovascular diseases (13.2%), all with recognized risk factors for atheromas. Of 76 patients who responded to follow up interviews, two (2.63%) died from cardiovascular stroke during an average follow up of 2.43 years.

Conclusions:  The results show carotid calcifications detected on panoramic radiographs can be used to help predict vascular strokes in patients. In cases where calcified carotid artery atheromas are detected, the dentist or oral and maxillofacial surgeon should refer the patient to a specialized physician.
Willingness of dentists in Jordan to treat HIV‐infected patients
Authors: El‐Maaytah M , Al Kayed A , Al Qudah M , Al Ahmad H , Al‐Dabbagh K , Jerjes W , Al Khawalde M , Abu Hammad O , Dar Odeh N , El‐Maaytah K , Al Shmailan Y , Porter S , Scully C
Published: August 2005

Reluctance of dentists to treat human immunodeficiency virus (HIV) positive patients represents a major concern. Many efforts have been extended towards the documentation of the extent of this reluctance and speculation of factors that influence it.

Objectives:  Assess the willingness of dentists in Jordan to treat HIV‐infected patients.

Materials and methods:  Two hundred and forty‐two general dental practices were surveyed for their willingness to provide treatment of toothache and routine dental care of an HIV‐infected individual.

Results:  Only 15% of the dental practices were willing to provide such care. Willingness to provide treatment did not seem to be influenced by financial factors or the local prevalence of HIV disease.

Conclusion:  Present data suggest that HIV‐infected individuals will have difficulty in obtaining dental health care in Jordan.
Number IV Erythema multiforme
Authors: Farthing P , Bagan J‐V , Scully C
Published: August 2005

Erythema multiforme (EM) is an acute mucocutaneous hypersensitivity reaction characterised by a skin eruption, with or without oral or other mucous membrane lesions. Occasionally EM may involve the mouth alone. EM has been classified into a number of different variants based on the degree of mucosal involvement and the nature and distribution of the skin lesions. EM minor typically affects no more than one mucosa, is the most common form and may be associated with symmetrical target lesions on the extremities. EM major is more severe, typically involving two or more mucous membranes with more variable skin involvement – which is used to distinguish it from Stevens‐Johnson syndrome (SJS), where there is extensive skin involvement and significant morbidity and a mortality rate of 5‐15%. Both EM major and SJS can involve internal organs and typically are associated with systemic symptoms. Toxic epidermal necrolysis (TEN) may be a severe manifestation of EM, but some experts regard it as a discrete disease. EM can be triggered by a number of factors, but the best documented is preceding infection with herpes simplex virus (HSV), the lesions resulting from a cell mediated immune reaction triggered by HSV–DNA. SJS and TEN are usually initiated by drugs, and the tissue damage is mediated by soluble factors including Fas and FasL.
An Intelligent Control Method Based on Fuzzy Logic for a Robotic Testing System for the Human Spine
Authors: Tian Lianfang
Published: August 2005

In previous biomechanical studies of the human spine, we implemented a hybrid controller to investigate load-displacement characteristics. We found that measurement errors in both position and force caused the controller to be less accurate than predicted. As an alternative to hybrid control, a fuzzy logic controller (FLC) has been developed and implemented in a robotic testing system for the human spine. An FLC is a real-time expert system that can emulate part of a human operator’s knowledge by using a set of action rules. The FLC provides simple but robust solutions that cover a wide range of system parameters and can cope with significant disturbances. It can be viewed as a heuristic and modular way of defining a nonlinear, table-based control system. In this study, an FLC is developed which uses the force difference and the change in force difference as the input parameters, and the displacement as the output parameter. A rule-table based on these parameters is designed for the controller. Experiments on a physical model composed of springs demonstrate the improved performance of the proposed method.
Pre-Strained Epimuscular Connections Cause Muscular Myofascial Force Transmission to Affect Properties of Synergistic EHL and EDL Muscles of the Rat
Authors: Yucesoy Can A. , Baan Guus C. , Koopman Bart H. F. J. M. , Grootenboer Henk J. , Huijing Peter A.
Published: August 2005

Background: Myofascial force transmission occurs between muscles (intermuscular myofascial force transmission) and from muscles to surrounding nonmuscular structures such as neurovascular tracts and bone (extramuscular myofascial force transmission). The purpose was to investigate the mechanical role of the epimuscular connections (the integral system of inter- and extramuscular connections) as well as the isolated role of extramuscular connections on myofascial force transmission and to test the hypothesis, if such connections are prestrained. Method of approach: Length-force characteristics of extensor hallucis longus (EHL) muscle of the rat were measured in two conditions: (I) with the neighboring EDL muscle and epimuscular connections of the muscles intact: EDL was kept at a constant muscle tendon complex length. (II) After removing EDL, leaving EHL with intact extramuscular connections exclusively. Results: (I) Epimuscular connections of the tested muscles proved to be prestrained significantly. (1) Passive EHL force was nonzero for all isometric EHL lengths including very low lengths, increasing with length to approximately 13% of optimum force at high length. (2) Significant proximodistal EDL force differences were found at all EHL lengths: Initially, proximal EDL force =1.18±0.11N, where as distal EDL force =1.50±0.08N (mean ± SE). EHL lengthening decreased the proximo-distal EDL force difference significantly (by 18.4%) but the dominance of EDL distal force remained. This shows that EHL lengthening reduces the prestrain on epimuscular connections via intermuscular connections; however; the prestrain on the extramuscular connections of EDL remains effective. (II) Removing EDL muscle affected EHL forces significantly. (1) Passive EHL forces decreased at all muscle lengths by approximately 17%. However, EHL passive force was still nonzero for the entire isometric EHL length range, indicating pre-strain of extramuscular connections of EHL. This indicates that a substantial part of the effects originates solely from the extramuscular connections of EHL. However, a role for intermuscular connections between EHL and EDL, when present, cannot be excluded. (2) Total EHL forces included significant shape changes in the length-force curve (e.g., optimal EHL force decreased significantly by 6%) showing that due to myofascial force transmission muscle length-force characteristics are not specific properties of individual muscles. Conclusions: The pre-strain in the epimuscular connections of EDL and EHL indicate that these myofascial pathways are sufficiently stiff to transmit force even after small changes in relative position of a muscle with respect to its neighboring muscular and nonmuscular tissues. This suggests the likelihood of such effects also in vivo.
Estimation of Vibration Power Absorption Density in Human Fingers
Authors: Dong Ren G. , Wu John Z. , Welcome Daniel E. , McDowell Thomas W.
Published: August 2005

The absorption of hand-transmitted vibration energy may be an etiological factor in vibration-induced disorders. The vibration power absorption density (VPAD) may be a better measure of energy than the total power absorption of the hand-arm system. The objectives of the present study are to develop a method to estimate the average absorption density in the fingers and to investigate its basic characteristics. Ten healthy male subjects were used in this study. The biodynamic response of the fingers in a power grip subjected to a broad-band random excitation was measured under three grip forces (15, 30, 50N) and three push forces (35, 45, 50N). The response was used to estimate the total finger energy absorption. The response, together with the finger volume, was also used to estimate the amount of tissue effectively involved in the absorption. Then, the average VPAD under constant-acceleration, constant-power density, constant-velocity vibration spectra, and 20 tool vibration spectra were calculated. The correlations between the VPAD and the unweighted and weighted accelerations (ISO 5349-1, 2001) were also examined. The VPAD depends on both the characteristics of the vibration spectrum and the biodynamic response of the finger-hand-arm system. The biodynamic response generally plays a more important role in determining the VPAD in the middle frequency range (31.5-400Hz) than those at the low and high ends. The applied force significantly affected the VPAD. The finger VPAD was highly correlated to the unweighted acceleration. The average VPAD can be determined using the proposed experimental method. It can serve as an alternative tool to quantify the severity of the vibration exposure for studying vibration-induced finger disorders.
Development and Validation of A C0–C7 FE Complex for Biomechanical Study
Authors: Zhang Qing Hang , Teo Ee Chon , Ng Hong Wan
Published: August 2005

In this study, the digitized geometrical data of the embalmed skull and vertebrae (C0–C7) of a 68-year old male cadaver were processed to develop a comprehensive, geometrically accurate, nonlinear C0–C7 FE model. The biomechanical response of human neck under physiological static loadings, near vertex drop impact and rear-end impact (whiplash) conditions were investigated and compared with published experimental results. Under static loading conditions, the predicted moment-rotation relationships of each motion segment under moments in midsagittal plane and horizontal plane agreed well with experimental data. In addition, the respective predicted head impact force history and the S-shaped kinematics responses of head-neck complex under near-vertex drop impact and rear-end conditions were close to those observed in reported experiments. Although the predicted responses of the head-neck complex under any specific condition cannot perfectly match the experimental observations, the model reasonably reflected the rotation distributions among the motion segments under static moments and basic responses of head and neck under dynamic loadings. The current model may offer potentials to effectively reflect the behavior of human cervical spine suitable for further biomechanics and traumatic studies.
Migration of Radio-Opaque Markers Injected Into Tendon Grafts: A Study Using Roentgen Stereophotogrammetric Analysis (RSA)
Authors: Smith Conrad Kay , Hull M. L. , Howell S. M.
Published: August 2005

An increase in anterior laxity following reconstruction of the anterior cruciate ligament (ACL) can result from lengthening of the graft construct either at the sites of fixation and/or between the sites of fixation (i.e., graft substance). Roentgen stereophotogrammetric analysis (RSA), which requires that radio-opaque markers be attached to the graft, has been shown to be a useful technique in determining lengthening in these regions. Previous methods have been used for attaching radio-opaque markers to the graft, but they all have limitations particularly for single-loop grafts. Therefore, the objective of this study was to evaluate injecting markers directly into the substance of a tendon as a viable method for measuring lengthening of single-loop graft constructs by determining the maximum amount of migration after cyclic loading. Tantalum spheres of 0.8 mm diameter were used as tendon markers. Ten single-loop tendon grafts were passed through tibial tunnels drilled in calf tibias and fixed with a tibial fixation device. Two tendon markers were inserted in one tendon bundle of each graft and the grafts were cyclically loaded for 225,000 cycles from 20 N to 170 N. At specified intervals, simultaneous radiographs were obtained of the tendon markers. Marker migration was computed as the change in distance between the two tendon markers parallel to the axis of the tibial tunnel. Marker migration had a root mean square (RMS) value of less than 0.1 mm. Because the RMS value indicates the error introduced into measurements of lengthening and because this error is negligible, the method described for attaching markers to single-loop ACL grafts has the potential to be useful for determining lengthening of single-loop ACL graft constructs in in vivo studies in humans.
Nutrient Utilization by Bovine Articular Chondrocytes: A Combined Experimental and Theoretical Approach
Authors: Sengers Bram G. , Heywood Hannah K. , Lee David A. , Oomens Cees W. J. , Bader Dan L.
Published: August 2005

A combined experimental-numerical approach was adopted to characterize glucose and oxygen uptake and lactate production by bovine articular chondrocytes in a model system. For a wide range of cell concentrations, cells in agarose were supplemented with either low or high glucose medium. During an initial culture phase of 48h, oxygen was monitored noninvasively using a biosensor system. Glucose and lactate were determined by medium sampling. In order to quantify glucose and oxygen uptake, a finite element approach was adopted to describe diffusion and uptake in the experimental model. Numerical predictions of lactate, based on simple relations for cell metabolism, were found to agree well for low glucose, but not for high glucose medium. Oxygen did not play a role in either case. Given the close association between chondrocyte energy metabolism and matrix synthesis, a quantifiable prediction of utilization can present a valuable contribution in the optimization of tissue engineering conditions.
Flow in a Mechanical Bileaflet Heart Valve at Laminar and Near-Peak Systole Flow Rates: CFD Simulations and Experiments
Authors: Ge Liang , Leo Hwa-Liang , Sotiropoulos Fotis , Yoganathan Ajit P.
Published: August 2005

Time-accurate, fully 3D numerical simulations and particle image velocity laboratory experiments are carried out for flow through a fully open bileaflet mechanical heart valve under steady (nonpulsatile) inflow conditions. Flows at two different Reynolds numbers, one in the laminar regime and the other turbulent (near-peak systole flow rate), are investigated. A direct numerical simulation is carried out for the laminar flow case while the turbulent flow is investigated with two different unsteady statistical turbulence modeling approaches, unsteady Reynolds-averaged Navier-Stokes (URANS) and detached-eddy simulation (DES) approach. For both the laminar and turbulent cases the computed mean velocity profiles are in good overall agreement with the measurements. For the turbulent simulations, however, the comparisons with the measurements demonstrate clearly the superiority of the DES approach and underscore its potential as a powerful modeling tool of cardiovascular flows at physiological conditions. The study reveals numerous previously unknown features of the flow.
From the Beach to the Sea Floor
Authors: Sponsel Alistair
Published: August 2005

Fathoming the Ocean
. The Discovery and Exploration of the Deep Sea.
By Helen M. Rozwadowski
. Harvard University Press, Cambridge, MA, 2005. 288 pp. $25.95, £16.95. ISBN 0-674-01691-2.

The author offers a scientific and cultural history of the early exploration of the ocean depths and their biota.
Computational Improvements Reveal Great Bacterial Diversity and High Metal Toxicity in Soil
Authors: Gans Jason , Wolinsky Murray , Dunbar John
Published: August 2005

The complexity of soil bacterial communities has thus far confounded effective measurement. However, with improved analytical methods, we show that the abundance distribution and total diversity can be deciphered. Reanalysis of reassociation kinetics for bacterial community DNA from pristine and metal-polluted soils showed that a power law best described the abundance distributions. More than one million distinct genomes occurred in the pristine soil, exceeding previous estimates by two orders of magnitude. Metal pollution reduced diversity more than 99.9%, revealing the highly toxic effect of metal contamination, especially for rare taxa.
Suppression of Aging in Mice by the Hormone Klotho
Authors: Kurosu Hiroshi , Yamamoto Masaya , Clark Jeremy D. , Pastor Johanne V. , Nandi Animesh , Gurnani Prem , McGuinness Owen P. , Chikuda Hirotaka , Yamaguchi Masayuki , Kawaguchi Hiroshi , Shimomura Iichiro , Takayama Yoshiharu , Herz Joachim , Kahn C. Ronald , Rosenblatt Kevin P. , Kuro-o Makoto
Published: August 2005

A defect in
Klotho
gene expression in mice accelerates the degeneration of multiple age-sensitive traits. Here, we show that overexpression of
Klotho
in mice extends life span. Klotho protein functions as a circulating hormone that binds to a cell-surface receptor and represses intracellular signals of insulin and insulin-like growth factor 1 (IGF1), an evolutionarily conserved mechanism for extending life span. Alleviation of aging-like phenotypes in Klotho-deficient mice was observed by perturbing insulin and IGF1 signaling, suggesting that Klotho-mediated inhibition of insulin and IGF1 signaling contributes to its anti-aging properties. Klotho protein may function as an anti-aging hormone in mammals.
High Frictional Anisotropy of Periodic and Aperiodic Directions on a Quasicrystal Surface
Authors: Park Jeong Young , Ogletree D. F. , Salmeron M. , Ribeiro R. A. , Canfield P. C. , Jenks C. J. , Thiel P. A.
Published: August 2005

Strong friction anisotropy is found when the twofold surface of an atomically clean aluminum-nickel-cobalt quasicrystal slides against a thiol-passivated titanium-nitride tip. Friction along the aperiodic direction is one-eighth as much as that along the periodic direction. This anisotropy, which is about three times as large as the highest value observed in anisotropic crystalline surfaces, disappears after the surface is oxidized in air. These results reveal a strong connection between interface atomic structure and the mechanisms by which energy is dissipated, which likely include electronic or phononic contributions, or both.
Gas Adsorption Sites in a Large-Pore Metal-Organic Framework
Authors: Rowsell Jesse L. C. , Spencer Elinor C. , Eckert Juergen , Howard Judith A. K. , Yaghi Omar M.
Published: August 2005

The primary adsorption sites for Ar and N
2
within metal-organic framework-5, a cubic structure composed of Zn
4
O(CO
2
)
6
units and phenylene links defining large pores 12 and 15 angstroms in diameter, have been identified by single-crystal x-ray diffraction. Refinement of data collected between 293 and 30 kelvin revealed a total of eight symmetry-independent adsorption sites. Five of these are sites on the zinc oxide unit and the organic link; the remaining three sites form a second layer in the pores. The structural integrity and high symmetry of the framework are retained throughout, with negligible changes resulting from gas adsorption.
Spatial Coordination of Spindle Assembly by Chromosome-Mediated Signaling Gradients
Authors: Caudron Maïwen , Bunt Gertrude , Bastiaens Philippe , Karsenti Eric
Published: August 2005

During cell division, chromosomes are distributed to daughter cells by the mitotic spindle. This system requires spatial cues to reproducibly self-organize. We report that such cues are provided by chromosome-mediated interaction gradients between the small guanosine triphosphatase (GTPase) Ran and importin-β. This produces activity gradients that determine the spatial distribution of microtubule nucleation and stabilization around chromosomes and that are essential for the self-organization of microtubules into a bipolar spindle.
VERTICAL SCALING OF TYPE I InP HBT WITH FT > 500 GHZ
Authors: LAI J. W. , HAFEZ W. , FENG M.
Published: August 2005

We have fabricated the high-speed InP/InGaAs -based single heterojunction bipolar transistors (SHBTs) with current gain cutoff frequency, fT from 166GHz to over 500GHz by the approach of vertical scaling. Collector thickness is reduced from 3000Å to 750Å and the peak current density is increased up to 1300kA/cm2. In this paper, device rf performance has been compared with respect to materials with different vertical dimensions. The scaling limitation is also studied by analytical approach. The extracted physical parameters suggest that the parasitic emitter resistance is the major limit on further enhancing ultra-scaled HBT intrinsic speed due to the associated RECBC delay. The cut-off frequency of a 500Å collector SHBT has been measured and the results indicate a dramatic drop on fT, supporting the conclusion projected by model analysis. It is also commented that for deeply downscaled HBTs, impact ionization could be another degrading mechanism limits device bandwidth.
TEMPERATURE DEPENDENCE OF TERAHERTZ EMISSION FROM SILICON DEVICES DOPED WITH BORON
Authors: TROEGER R. T. , ADAM T. N. , RAY S. K. , LV P.-C. , KIM S. , KOLODZEY J.
Published: August 2005

In this paper, we report on electrically pumped terahertz emitters based on silicon doped with boron acceptors. At cryogenic temperatures, three narrow spectral emission lines attributed to radiative transitions from p-like excited hydrogenic states to the s-like Γ8 ground state associated with the boron dopants were observed centered around 8 THz. The spectral emission line center frequencies were in remarkable agreement with values reported from absorption measurements and theoretical calculations. The total time-resolved terahertz emission power was found to be up to 31 μW per device facet. We have solved the rate equations describing the populations in the hydrogenic dopant states involved in the emission mechanism and derived expressions for the current pumping and temperature dependence of the emitted terahertz power, yielding excellent agreement with the experimental data. These results suggest that silicon-based terahertz emitters may be fabricated without epitaxial quantum wells. The observed temperature dependence suggests that electric field assisted thermal escape of carriers from upper hydrogenic states may be responsible for lower output powers at higher temperatures.