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Macroscopic
Terms modified by Macroscopic Selected AbstractsReplacement of the medial tibial plateau by a metallic implant in a goat modelJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2010Roel J.H. Custers Abstract The purposes of the present study were to explore the surgical possibilities for replacement of the medial tibial plateau by a metallic implant in a large animal model and to examine the implications for the opposing cartilage. In six goats, the medial tibial plateau of the right knee was replaced by a cobalt,chromium implant, using polymethylmethacrylate bone cement for fixation. The unoperated left knee served as a control. At 26 weeks after surgery, the animals were killed, and the joints evaluated macroscopically. Cartilage quality was analyzed macroscopically and histologically. Glycosaminoglycan content, synthesis, and release were measured in tissue and medium. All animals were able to move and load the knees without any limitations. Macroscopic articular evaluation scores showed worsening 26 weeks after inserting the implant (p,<,0.05). Macroscopic and histologic scores showed more cartilage degeneration of the opposing medial femoral condyle in the experimental knee compared to the control knee (p,<,0.05). Higher glycosaminoglycan synthesis was measured at the medial femoral condyle cartilage in the experimental knees (p,<,0.05). This study shows that the medial tibial plateau can be successfully replaced by a cobalt,chromium implant in a large animal model. However, considerable femoral cartilage degeneration of the medial femoral condyle was induced, suggesting that care must be taken introducing hemiarthroplasty devices in a human clinical setting for the treatment of postmeniscectomy cartilage degeneration of the medial tibial plateau. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:429,435, 2010 [source] Heterogeneity in skin treated with low-frequency ultrasoundJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2008Joseph Kushner IV Abstract Recent experimental evidence using colored, fluorescent permeants suggests that skin treated with low-frequency sonophoresis (LFS) is perturbed in a heterogeneous manner. Macroscopic and microscopic visualization studies, topical penetration studies, transdermal permeability studies, and skin electrical resistivity measurements have shown that discrete domains, referred to as localized transport regions (LTRs), which are formed during LFS treatment of the skin, possess greatly reduced barrier properties, and therefore exhibit increased permeant skin penetration, compared to the surrounding regions of LFS-treated skin. The transformation of LTR formation from a heterogeneous to a homogeneous phenomenon has the potential benefit of increasing the maximum level of transdermal permeability or of reducing the area of skin required to deliver a desired dose of drug transdermally. Future studies, aimed at elucidating both the mechanisms of LTR formation and the limits of nondamaging formation of LTRs in the skin, are required to incorporate these proposed improvements to enhance the efficacy and practical utility of low-frequency sonophoresis. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:4119,4128, 2008 [source] Overexpressed growth hormone (GH) synergistically promotes carcinogen-initiated liver tumour growth by promoting cellular proliferation in emerging hepatocellular neoplasms in female and male GH-transgenic miceLIVER INTERNATIONAL, Issue 2 2001Kenneth J. Snibson Abstract:Background/Aims: Growth hormone (GH), when overexpressed in male and female GH-transgenic mice, is known to induce liver tumours within 1 year. This study aimed to gain a clearer understanding of the interaction between GH and tumour cells in vivo. Methods/Results: The carcinogen diethylnitrosomine (DEN) was administered to neo-natal transgenic and non-transgenic mice maintained in a "hepatocarcinogenesis resistant" genetic background (C57BL/6J). Macroscopic, microscopic and liver weight/body weight ratio analyses revealed that carcinogen-induced hepatocarcinogenesis was dramatically accelerated in young GH-transgenic mice compared to non-transgenic counterparts. Image analysis of microscopic hepatocellular neoplasms showed rapidly increasing tumour burdens, and neoplastic foci size over time in young adult GH-transgenic mice. The magnitude of enhanced tumour growth was equivalent in both male and female transgenic mice, whereas much lower and sexually dimorphic tumour growth rates (males>females) were observed in non-transgenic mice treated with DEN. BrdU labelling experiments demonstrated that rapid tumour growth in carcinogen-treated GH-transgenic mice was due to the promotion of cell proliferation in emerging lesions. Tumour cell proliferation in young GH-transgenic mice was 2.6- and 4-fold higher, respectively, than that observed in similar age male and female non-transgenic mice. Interestingly, both GH-transgenic and non-transgenic mice displayed progressively slower tumour growth rates in older animals. Conclusion: Overall, GH synergistically promotes carcinogen-induced hepatocarcinogenesis in both sexes of GH-transgenic mice by stimulating tumour cell proliferation. [source] The Zak,odzie enstatite meteorite: Mineralogy, petrology, origin, and classificationMETEORITICS & PLANETARY SCIENCE, Issue S9 2005Tadeusz A. PRZYLIBSKI Macroscopic and microscopic observations (in transmitted and reflected light), microprobe analyses, cathodoluminescence images, and X-ray diffraction data show that the meteorite is composed of clino- and orthoenstatite, two generations of feldspars, relict olivine (forsterite), a polymorph of SiO2 (apparently cristobalite), and opaque minerals: Fe-Ni alloy (kamacite and taenite), troilite, schreibersite, graphite, and sulfide (Mg, Mn, Fe)S, which is probably keilite. The texture is fine- to inequigranular of cumulate type, locally intergranular. The MgS-FeS thermometer indicates that the sulfides crystallized at ,580,600 °:C. Thus, the Zaklodzie meteorite formed by the nearly complete melting of an enstatite chondrite protolith, probably at ,4.4 Ga; the process was likely caused by the decay of the 26Al nuclide in the planetesimal interior. The second stage of its evolution, which could have happened at ,2.1 Ga, involved partial re-melting of most fusible components, probably due to collision with another body. The structure, composition, and origin of the meteorite and its relation to the parent rock indicate that Zaklodzie may represent a primitive enstatite achondrite. [source] Prenatal diagnosis of Bruck syndromePRENATAL DIAGNOSIS, Issue 7 2005C. Berg Abstract Bruck syndrome is an autosomal recessive connective tissue disorder combining features of osteogenesis imperfecta and arthrogryposis multiplex congenita. There are only few reports describing this rare syndrome of multiple fractures and joint contractures that is thought to be a subtype of osteogenesis imperfecta. We report the first case of prenatal diagnosis of this syndrome in a fetus at 23 weeks of gestation. Ultrasound findings included brachycephaly, retrognathia marked shortening and bowing of both femurs, bilateral fixed flexion of the elbows, bilateral fixed extension of the wrists and partially fixed flexion of the knees. The parents opted for termination of pregnancy. Macroscopic and radiologic examination of the aborted fetus confirmed the prenatal diagnosis, whereas morphological studies of the bone tissue found no hard evidence of osteogenesis imperfecta, probably due to the early stage of pregnancy and the heterogeneity of the syndrome itself. Copyright © 2005 John Wiley & Sons, Ltd. [source] Macroscopic and Microscopic Anatomy of the Oviduct in the Sexually Mature Rhea (Rhea americana)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 3 2008R. C. Parizzi Summary The morphological characteristics of the oviduct of 12 sexually mature rheas (Rhea americana) were studied. Only the left oviduct is developed as a long tube with a length of 122 ± 23.1 cm, and is subdivided into infundibulum (15.2 ± 4.0 cm), magnum (63.3 ± 9.4 cm), isthmus (5.6 ± 3.1 cm), uterus (16.0 ± 4.2 cm) and vagina (11.5 ± 1.4 cm). The mucous membrane of the oviduct, as a whole, possesses luminal folds covered by ciliated columnar epithelium with secretory cells. The infundibulum part presents a cranial opening with thin and long fimbriae with few tubular glands in caudal tubular portion. In the magnum, the largest portion of the oviduct, the folds are thicker and are filled with tubular glands. The isthmus is short and presents less bulky folds and a few tubular glands. A bag-shaped uterus in the cranial area shows thin folds, and in the caudal region (shell gland) more ramified folds with few tubular glands. The vagina has long luminal folds and a thick muscular tunic; no glands with sperm-storage characteristics have been observed. In conclusion, the oviduct in sexually mature rhea has morphological similarities with the other species of birds already described; however it presents its own characteristics to produce a big egg. [source] Evolution of Ordered Block Copolymer Serpentines into a Macroscopic, Hierarchically Ordered Web,ANGEWANDTE CHEMIE, Issue 44 2009Won Hong Von Ringen zu Netzen: Das Verdampfen von Diblockcopolymerlösungen in einer Kugel-auf-Ebene-Geometrie liefert über große Bereiche konzentrische Mikrostrukturen (links im Bild). Durch selektives Tempern mit Lösungsmitteldampf lagern sich diese Mikrostrukturen in ein makroskopisches Muster aus regelmäßig angeordneten mikroporösen Maschen um (rechts im Bild), und zugleich entstehen Domänen aus nanoskopischen Diblockcopolymer-Zylindern. [source] The neuropathology of probable Alzheimer disease and mild cognitive impairment,ANNALS OF NEUROLOGY, Issue 2 2009Julie A. Schneider MD Objective Mixed pathologies are common in older persons with dementia. Little is known about mixed pathologies in probable Alzheimer disease (AD) and about the spectrum of neuropathology in mild cognitive impairment (MCI). The objective of this study was to investigate single and mixed common age-related neuropathologies in persons with probable AD and MCI. Methods The study included 483 autopsied participants from the Religious Orders Study and the Rush Memory and Aging Project with probable AD (National Institute of Neurological and Communicative Disorders and Stroke,Alzheimer's Disease and Related Disorders Association criteria), MCI (amnestic and nonamnestic), or no cognitive impairment. We excluded 41 persons with clinically possible AD and 14 with other dementias. We documented the neuropathology of AD (National Institute on Aging,Reagan criteria), macroscopic cerebral infarcts, and neocortical Lewy body (LB) disease. Results Of 179 persons (average age, 86.9 years) with probable AD, 87.7% had pathologically confirmed AD, and 45.8% had mixed pathologies, most commonly AD with macroscopic infarcts (n = 54), followed by AD with neocortical LB disease (n = 19) and both (n = 8). Of the 134 persons with MCI, 54.4% had pathologically diagnosed AD (58.7% amnestic; 49.2% nonamnestic); 19.4% had mixed pathologies (22.7% amnestic; 15.3% nonamnestic). Macroscopic infarcts without pathologically diagnosed AD accounted for 4.5% of probable AD, 13.3% of amnestic MCI, and 18.6% of nonamnestic MCI. Pure neocortical LB disease was uncommon in all persons with cognitive impairment (<6%). Microscopic infarcts (without macroscopic infarcts) were common as a mixed pathology, but rarely accounted for a clinical diagnosis of probable AD (n = 4) or MCI (n = 3). Interpretation Clinically diagnosed probable AD and MCI, even amnestic MCI, are pathologically heterogeneous disorders, with many persons exhibiting mixed pathologies. Ann Neurol 2009;66:200,208 [source] In vivo selective inhibition of mitogen-activated protein kinase kinase 1/2 in rabbit experimental osteoarthritis is associated with a reduction in the development of structural changesARTHRITIS & RHEUMATISM, Issue 6 2003Jean-Pierre Pelletier Objective The primary aim of this study was to investigate, using an experimental rabbit model of osteoarthritis (OA), the effect of a selective mitogen-activated protein kinase kinase 1/2 (MEK-1/2) inhibitor, PD 198306, on the development of structural changes. Additional aims were to assess the effects of the inhibitor on levels of phosphorylated extracellular signal,regulated kinase 1/2 (phospho,ERK-1/2) and matrix metalloproteinase 1 (MMP-1; collagenase 1) in OA chondrocytes. Methods After surgical sectioning of the anterior cruciate ligament of the right knee joint, rabbits with OA were separated into 3 experimental groups: oral treatment with placebo or with PD 198306 at a therapeutic concentration of 10 mg/kg/day or 30 mg/kg/day. Each treatment started immediately after surgery. The animals were killed 8 weeks after surgery. Macroscopic and histologic studies were performed on the cartilage and synovial membrane. The levels of phospho,ERK-1/2 and MMP-1 in OA cartilage chondrocytes were evaluated by immunohistochemistry. Normal, untreated rabbits were used as controls. Results OA rabbits treated with the highest dosage of MEK-1/2 inhibitor showed decreases in the surface area (size) of cartilage macroscopic lesions (P < 0.002) and in osteophyte width on the lateral condyles (P = 0.05). Histologically, the severity of synovial inflammation (villous hyperplasia) was also reduced (P < 0.02). In cartilage from placebo-treated OA rabbits, a significantly higher percentage of chondrocytes in the superficial layer stained positive for phospho,ERK-1/2 and MMP-1 compared with normal controls. Rabbits treated with the highest dosage of PD 198306 demonstrated a significant and dose-dependent reduction in the level of phospho,ERK-1/2 and a lower level of MMP-1. Conclusion This study demonstrates that, in vivo, PD 198306, a selective inhibitor of MEK-1/2, can partially decrease the development of some of the structural changes in experimental OA. This effect was associated with a reduction in the level of phospho,ERK-1/2 in OA chondrocytes, which probably explains the action of the drug. [source] Biodisk: A new device for closure of patent foramen ovale: A feasibility study in swine,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 6 2010Dusan Pavcnik MD Abstract Purpose: To evaluate the feasibility, effectiveness, and safety of a porcine small intestinal submucosa (SIS)-covered Biodisk (BD) for the closure of patent foramen ovale (PFO) in swine. Methods: Twelve piglets (9,30 kg) with PFO ranging in size from 6 to 12 mm were used for the in vivo testing. The BD device consisted of two basic nitinol wire components covered with platinum coil, a flexible SIS-covered ring, and an anchor. The BD was advanced through an 8-Fr sheath from the femoral vein. Nine acute animals were used to test the BD for deployment, stability, immediate shunt closure, and device repositioning before or after its detachment. To assess retrievability, four devices were deployed and intentionally embolized into the RA (n = 2) and LA (n = 2). The effectiveness of the device was evaluated by angiocardiography. EKG was recorded before and after PFO closure for 3 hr. From the 12 animals, nine were acute and three were followed; one for 6 weeks, one for 12 weeks, and one for 16 weeks. Results: Successful device implantation was achieved in all animals with no shunting of contrast media observed during follow-up in. One animal needed to have device repositioned for complete PFO occlusion because of suboptimal placement at the first attempt. The device was easily placed and retrieved before detachment in all nine animals in the acute study. None of the BDs spontaneously embolized during release or on follow-up. EKG did not demonstrate arrhythmias during or after treatment. Four intentionally embolized BDs were easily retrieved with an Amplatz goose neck snare. Macroscopic and histologic evaluation of the three long-term animals showed that devices were well incorporated in the atrial septum with complete shunt closure. The SIS showed progressive remodeling with the host cells. There was also progressive endothelization of the BD device. Conclusion: The BD device deployment is feasible, safe, and effective. Long-term studies are needed to evaluate its long-term effectiveness. © 2010 Wiley-Liss, Inc. [source] Magnetic susceptibility: Further insights into macroscopic and microscopic fields and the sphere of LorentzCONCEPTS IN MAGNETIC RESONANCE, Issue 1 2003C.J. Durrant Abstract To make certain quantitative interpretations of spectra from NMR experiments carried out on heterogeneous samples, such as cells and tissues, we must be able to estimate the magnetic and electric fields experienced by the resonant nuclei of atoms in the sample. Here, we analyze the relationships between these fields and the fields obtained by solving the Maxwell equations that describe the bulk properties of the materials present. This analysis separates the contribution to these fields of the molecule in which the atom in question is bonded, the "host" fields, from the contribution of all the other molecules in the system, the "external" fields. We discuss the circumstances under which the latter can be found by determining the macroscopic fields in the sample and then removing the averaged contribution of the host molecule. We demonstrate that the results produced by the, so-called, "sphere of Lorentz" construction are of general validity in both static and time-varying cases. This analytic construct, however, is not "mystical" and its justification rests not on any sphericity in the system but on the local uniformity and isotropy, i.e., spherical symmetry, of the medium when averaged over random microscopic configurations. This local averaging is precisely that which defines the equations that describe the macroscopic fields. Hence, the external microscopic fields, in a suitably averaged sense, can be estimated from the macroscopic fields. We then discuss the calculation of the external fields and that of the resonant nucleus in NMR experiments. © 2003 Wiley Periodicals, Inc. Concepts Magn Reson Part A 18A: 72,95, 2003 [source] Efficacy of the Flashlamp-Pumped Pulsed-Dye Laser in Nonsurgical Delay of Skin FlapsDERMATOLOGIC SURGERY, Issue 7 2003Ali Riza Erçöçen MD Objective. The purpose of this article was to determine the effectiveness of laser delay by use of the flashlamp-pumped pulsed-dye laser operating at a wavelength of 585 nm; to elucidate the comparable or dissimilar macroscopic, microscopic, and hemodynamic changes between laser and surgical delay methods; and to clarify the possible mechanisms underlying the delay effect of laser. Methods. A standardized caudally based random dorsal rat flap model was used in this study: Acute random skin flaps served as control subjects (group 1). Surgical delay was employed by incision of lateral longitudinal borders both without (group 2) and with (group 3) undermining, and laser delay methods were performed by laser irradiation of both lateral longitudinal borders (group 4) and the entire surface (group 5) of the proposed flap. Evaluation was done by histologic examination, India ink injection, laser Doppler perfusion imaging, and measurement of flap survival. Results. Histologically, dilation and hypertrophy of subpapillary and subdermal vessels were evident in groups 2, 3, and 4; on the other hand, degranulation of mast cells in the vicinity of occluded vessels at the 1st hour of laser delay and a striking mast cell proliferation and degranulation in association with newly formed vessels (angiogenesis) at the 14th day of laser delay were prominent in group 5. India ink injections revealed longitudinally arranged large-caliber vessels and cross-filling between the vessels of adjacent territories in groups, 2, 3, and 4, but only small-caliber vessels in group 5. Compared with the acute flaps, both surgical and laser delay significantly increased the mean flap perfusion to the maximal levels after a 14-day delay period, and all delay procedures improved flap survival; the most significant increase in surviving area was observed in group 3, whereas the less significant increase in surviving area was in group 5. Conclusion. This study demonstrates that laser delay is as effective as surgical delay and that laser delay by lasering lateral borders leads to dilation and longitudinal rearrangement of the existing vessels rather than angiogenesis, whereas laser delay by lasering the entire surface results in delay effect by inducing angiogenesis due to activation and degranulation of the mast cells. [source] No change in the structure of the brain in migraine: a voxel-based morphometric studyEUROPEAN JOURNAL OF NEUROLOGY, Issue 1 2003M. S. Matharu Migraine is a common, disabling form of primary neurovascular headache. For most of the twentieth century it was regarded as a vascular headache whose primary pathophysiology lay in the cranial vasculature. Functional brain imaging using positron emission tomography has demonstrated activation of the rostral brain stem in acute migraine. Voxel-based morphometry is a new fully automated whole brain technique that is sensitive to subtle macroscopic and mesoscopic structural differences between groups of subjects. In this study 11 patients suffering from migraine with aura (10 females, one male: 23,52 years, mean 31); 11 controls (10 females, one male: 23,52, mean 31); 17 patients with migraine without aura (16 females, one male: 24,57, mean 34); 17 controls (16 females, one male: 24,57, mean 34) were imaged with high resolution volumetric magnetic resonance imaging. There was no significant difference in global grey or white matter volumes between either patients with migraine and controls, or patients with aura and without aura. This study did not show any global or regional macroscopic structural difference between patients with migraine and controls, with migraine sufferers taken as homogenous groups. If structural changes are to be found, other methods of phenotyping migraine, such as by genotype or perhaps treatment response, may be required to resolve completely whether there is some subtle structural change in the brain of patients with migraine. [source] Structure, reactivity and spectroscopic properties of minerals from lateritic soils: insights from ab initio calculationsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 4 2007E. Balan Summary We review here some recent applications of ab initio calculations to the modelling of spectroscopic and energetic properties of minerals, which are key components of lateritic soils or govern their geochemical properties. Quantum mechanical ab initio calculations are based on density functional theory and density functional perturbation theory. Among the minerals investigated, zircon is a typical resistant primary mineral. Its resistance to weathering is at the origin of the peculiar geochemical behaviour of Zr, an element often used in mass balance calculations of continental weathering. Numerical modelling gives a unique picture of the origin of the chemical durability and radiation-induced amorphization of zircon. We also present several applications of ab initio calculations to the description of properties of secondary minerals, such as kaolinite-group minerals and gibbsite. Special attention is given to the calculation of infrared and Raman spectra. Surface properties and particle shape are major properties of finely-divided materials such as clay minerals. We show how theoretical modelling of infrared spectroscopic data provides information on natural samples at both the microscopic (atomic structure) and macroscopic (particle shape) length-scale. The systematic comparison of experimental and theoretical data significantly improves our understanding of mineral transformations during soil formation and evolution in lateritic environments. [source] VACCINATION, WITHIN-HOST DYNAMICS, AND VIRULENCE EVOLUTIONEVOLUTION, Issue 1 2006Jean-Baptiste André Abstract We explore the potential consequences of vaccination on parasite epidemiology and evolution. Our model combines a microscopic (within-host dynamics) and a macroscopic (epidemiological dynamics) description of the interaction between the parasite and its host. This approach allows relevant epidemiological traits such as parasite transmission, parasite virulence, and host recovery to emerge from a mechanistic model of acute infection describing the interaction between the parasite and the host immune system. We model the effect of a vaccine as an activator of immunity enhancing the replication rate of lymphocytes, their initial density at infection's initiation, their efficacy to kill the parasite, or their activation delay after infection. We analyze the evolution of the replication rate of parasites and show that vaccination may promote the evolution of faster replicating and, consequently, more virulent strains. We also show that intermediate vaccination coverage may lead to the coexistence of two different parasite strategies (a low-virulence strain adapted to naive hosts, and a high-virulence strain, more generalist, adapted to both naive and vaccinated hosts). We discuss the consequences of various vaccination strategies under different epidemiological situations using several distinct measures to evaluate the cost induced by the parasite on individuals and entire host populations. [source] Amorphous Calcium Carbonate is Stabilized in ConfinementADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Christopher J. Stephens Abstract Biominerals typically form within localized volumes, affording organisms great control over the mineralization process. The influence of such confinement on crystallization is studied here by precipitating CaCO3 within the confines of an annular wedge, formed around the contact point of two crossed half-cylinders. The cylinders are functionalized with self-assembled monolayers of mercaptohexadecanoic acid on gold. This configuration enables a systematic study of the effects of confinement since the surface separation increases continuously from zero at the contact point to macroscopic (mm) separations. While oriented rhombohedral calcite crystals form at large (>10,µm) separations, particles with irregular morphologies and partial crystallinity are observed as the surface separation approaches the dimensions of the unconfined crystals (5,10,µm). Further increase in the confinement has a significant effect on the crystallization process with flattened amorphous CaCO3 (ACC) particles being formed at micrometer separations. These ACC particles show remarkable stability when maintained within the wedge but rapidly crystallize on separation of the cylinders. A comparison of bulk and surface free-energy terms shows that ACC cannot be thermodynamically stable at these large separations, and the stability is attributed to kinetic factors. This study therefore shows that the environment in which minerals form can have a significant effect on their stability and demonstrates that ACC can be stabilized with respect to the crystalline polymorphs of CaCO3 by confinement alone. That ACC was stabilized at such large (micrometer) separations is striking, and demonstrates the versatility of this strategy, and its potential value in biological systems. [source] Bringing quantum strangeness to the macroscopic worldFORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 4-5 2003S. Mancini We show that bouncing laser beams can entangle massive oscillators like movable mirrors. Such entanglement results robust against thermal noise and detectable with common optomechanical apparatus. Thus, a quantum strangeness (entanglement) can be brought to the macroscopic, everyday, world. [source] Hydraulic pathways in the crystalline rock of the KTBGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2000Günter Zimmermann Fracture systems and fluid pathways must be analysed in order to understand the dynamical processes in the upper crust. Various deterministic as well as stochastic fracture networks in the depth section of the Franconian Lineament (6900 to 7140 m), which appears as a brittle ductile shear zone and prominent seismic reflector, were modelled to simulate the hydraulic situation at the two boreholes of the Continental Deep Drilling Program (KTB). They led to estimations of the hydraulic permeability in crystalline rock. The geometrical parameters of the fractures, such as fracture locations and orientations, were determined from structural borehole measurements, which create an image of the borehole wall. The selection of potentially open fractures was decided according to the stress field. Only fractures with the dip direction (azimuth) of the fracture plane perpendicular to the maximum horizontal stress field were assumed to be open. The motivation for this assumption is the fact that the maximum horizontal stress is higher than the vertical stress from the formation, indicating that the state of stress is a strike-slip faulting. Therefore, the probability of open fractures due to this particular stress field at the KTB sites is enhanced. Length scales for fracture apertures and extensions were stochastically varied and calibrated by hydraulic experiments. The mean fracture aperture was estimated to be 25 ,m, assuming an exponential distribution, with corresponding permeability in the range of 10,16 m2. Similar results were also obtained for log-normal and normal distributions, with a variation of permeability of the order of a factor of 2. The influence of the fracture length on permeability of the stochastic networks was also studied. Decreasing the fracture length beyond a specific threshold of 10 m led to networks with vanishing connectivity and hence vanishing permeability. Therefore, we assume a mean fracture length exceeding the threshold of 10 m as a necessary assumption for a macroscopic hydraulically active fracture system at the KTB site. The calculated porosity due to the fracture network is of the order of 10,3 per cent, which at first sight contradicts the estimated matrix porosity of 1 to 2 per cent from borehole measurements and core measurements. It can be concluded from these results, however, that if the fluid transport is due to a macroscopic fracture system, only very low porosity is needed for hydraulic flow with permeabilities up to several 10,16 m2, and hence the contribution of matrix porosity to the hydraulic transport is of a subordinate nature. [source] Source Zone Natural Attenuation at Petroleum Hydrocarbon Spill Sites,I: Site-Specific Assessment ApproachGROUND WATER MONITORING & REMEDIATION, Issue 4 2006Paul Johnson This work focuses on the site-specific assessment of source zone natural attenuation (SZNA) at petroleum spill sites, including the confirmation that SZNA is occurring, estimation of current SZNA rates, and anticipation of SZNA impact on future ground water quality. The approach anticipates that decision makers will be interested in answers to the following questions: (1) Is SZNA occurring and what processes are contributing to SZNA? (2) What are the current rates of mass removal associated with SZNA? (3) What are the longer-term implications of SZNA for ground water impacts? and (4) Are the SZNA processes and rates sustainable? This approach is a data-driven, macroscopic, multiple-lines-of-evidence approach and is therefore consistent with the 2000 National Research Council's recommendations and complementary to existing dissolved plume natural attenuation protocols and recent modeling work published by others. While this work is easily generalized, the discussion emphasizes SZNA assessment at petroleum hydrocarbon spill sites. The approach includes three basic levels of data collection and data reduction (Group I, Group II, and Group III). Group I measurements provide evidence that SZNA is occurring. Group II measurements include additional information necessary to estimate current SZNA rates, and group III measurements are focused on evaluating the long-term implications of SZNA for source zone characteristics and ground water quality. This paper presents the generalized site-specific SZNA assessment approach and then focuses on the interpretation of Group II data. Companion papers illustrate its application to source zones at a former oil field in California. [source] Outcome of treatment for advanced cervical metastatic squamous cell carcinomaHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 2 2005Jonathan Clark FRACS Abstract Background. Patients with advanced cervical metastases from mucosal squamous cell carcinoma have a poor prognosis because of their high risk of regional and distal failure. This study aims to evaluate the outcomes of patients with clinical N2 or N3 disease managed with surgery and postoperative radiotherapy. Methods. From a comprehensive computerized database, 181 entered patients who had neck dissection for N2 or N3 disease between 1988 and 1999 were evaluated. The mean age was 62 years, and minimum follow-up was 3 years. Results. A total of 233 neck dissections were performed in 181 patients, including 163 comprehensive and 70 selective dissections. Postoperative radiotherapy was given in 82% of cases. The local control rate was 75% at 5 years, and control of disease in the treated neck was achieved in 86%. Macroscopic extracapsular spread (ECS) significantly increased regional recurrence (p = .001). Adjuvant radiotherapy significantly improved neck control (p = .004) but did not alter survival. Patients with ECS (both microscopic and macroscopic) who received radiotherapy had a significantly better survival than did patients with ECS who did not receive radiotherapy. Disease-specific survival for the entire group was 39% at 5 years. By use of multivariate analysis, macroscopic ECS and N2c neck disease were independent adverse prognostic factors for survival (p = .001). Conclusions. Despite a high rate of control in the treated neck, the poor survival (39%) in this patient group indicates that adjuvant therapeutic strategies need to be considered. © 2004 Wiley Periodicals, Inc. Head Neck27: 87,94, 2005 [source] Cover Picture: Hierarchically Organized Superstructure Emerging from the Exquisite Association of Inorganic Crystals, Organic Polymers, and Dyes: A Model Approach Towards Suprabiomineral Materials (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 9 2005Mater. Abstract Suprabiomineral materials possessing hierarchically organized superstructures are investigated by Imai and Oaki on p.,1407. Inorganic crystals, organic polymers, and functional dyes have assembled via a simple biomimetic route into a superstructure that contains six different tiers, from the macroscale to the nanoscale. The hierarchy originates from the strong interaction between crystals and polymers and the diffusion-controlled conditions. The versatile role of the polymer is found to be essential for the construction of a superstructure. This approach promises to generate novel types of functional materials with controllable structures and properties. We report a novel hierarchically organized superstructure emerging from an exquisite association of inorganic crystals, organic polymers, and dyes. The resultant K2SO4/poly(acrylic acid) composite includes five different tiers from the nanoscopic to the macroscopic. An additional new tier leading to functionality is formed by the incorporation of organic dyes that are organized in a nanospace. The emergent superstructure and properties are designed through changes in polymer concentration. The multiple roles of the polymer realize the generation of the architecture at each size scale. This model approach should be widely applicable to other systems, allowing for the preparation of innovative materials by an appropriate combination of crystals, polymers, and functional molecules. [source] A new method for measuring ice adhesion strength at an ice,substrate interfaceHYDROLOGICAL PROCESSES, Issue 4 2006M. Javan-Mashmool Abstract This research focuses on the development of a direct technique for measuring atmospheric ice adhesion strength using embedded piezoelectric film sensors at the ice-substrate interface. The substrate is a small aluminium beam on which PVDF piezoelectric sensors are bonded. The composite beam formed by aluminium and an ice layer is submitted to sinusoidal stress at the interface by a shaker on which one end of the beam is clamped. The piezoelectric charge coefficient is used to predict the electric charge density induced on the piezoelectric film, which enables us to develop a macroscopic and direct measurement technique for determining mechanical stresses at the atmospheric-ice-substrate interface. The preliminary results obtained show that adhesive failure was obtained for each test for a frequency close to the natural resonance frequency of the aluminium beam. Within the limitations of the experimental conditions, it was possible using this approach to obtain ice adhesion strengths in accordance with those obtained in the literature. This demonstrates the feasibility of this simple ice adhesion testing method. Copyright © 2006 John Wiley & Sons, Ltd. [source] Activation of the cannabinoid 2 receptor (CB2) protects against experimental colitisINFLAMMATORY BOWEL DISEASES, Issue 11 2009Martin A. Storr MD Abstract Background: Activation of cannabinoid (CB)1 receptors results in attenuation of experimental colitis. Our aim was to examine the role of CB2 receptors in experimental colitis using agonists (JWH133, AM1241) and an antagonist (AM630) in trinitrobenzene sulfonic acid (TNBS)-induced colitis in wildtype and CB2 receptor-deficient (CB mice. Methods: Mice were treated with TNBS to induce colitis and then given intraperitoneal injections of the CB2 receptor agonists JWH133, AM1241, or the CB2 receptor antagonist AM630. Additionally, CB mice were treated with TNBS and injected with JWH133 or AM1241. Animals were examined 3 days after the induction of colitis. The colons were removed for macroscopic and microscopic evaluation, as well as the determination of myeloperoxidase activity. Quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) for CB2 receptor was also performed in animals with TNBS and dextran sodium sulfate colitis. Results: Intracolonic installation of TNBS caused severe colitis. CB2 mRNA expression was significantly increased during the course of experimental colitis. Three-day treatment with JWH133 or AM1241 significantly reduced colitis; AM630 exacerbated colitis. The effect of JWH133 was abolished when animals were pretreated with AM630. Neither JWH133 nor AM1241 had effects in CB mice. Conclusions: We show that activation of the CB2 receptor protects against experimental colitis in mice. Increased expression of CB2 receptor mRNA and aggravation of colitis by AM630 suggests a role for this receptor in normally limiting the development of colitis. These results support the idea that the CB2 receptor may be a possible novel therapeutic target in inflammatory bowel disease. (Inflamm Bowel Dis 2009) [source] Plant sterol guggulsterone inhibits nuclear factor-,B signaling in intestinal epithelial cells by blocking I,B kinase and ameliorates acute murine colitisINFLAMMATORY BOWEL DISEASES, Issue 12 2006Jae Hee Cheon MD Abstract Background/Aims: The plant sterol guggulsterone has been shown to have anti-inflammatory properties. It remains unknown, however, whether guggulsterone is effective for the treatment of inflammatory bowel disease (IBD). Therefore, we investigated anti-inflammatory effects of guggulsterone on intestinal epithelial cells (IEC) and on experimental murine colitis models and elucidated its molecular mechanisms. Methods: Human Caco-2 cells and rat non-transformed IEC-18 cells were stimulated with interleukin (IL)-1, or lipopolysaccharide (LPS) with or without guggulsterone. The effects of guggulsterone on nuclear factor (NF)-,B signaling in IEC were examined by intercellular adhesion molecule (ICAM)-1 real-time reverse-transcription polymerase chain reaction, NF-,B transcriptional activity assay, Western blotting for I,B phosphorylation/degradation, electrophoretic mobility shift assay, and in vitro I,B kinase (IKK) assay. For in vivo study, dextran sulfate sodium (DSS)-treated mice were fed with or without guggulsterone. Colitis was quantified by disease activity index and evaluation of macroscopic and microscopic findings. Phosphorylation of I,B and IKK in colon mucosa was assessed by Western blotting and immunohistochemistry. Results: Guggulsterone significantly inhibited LPS- or IL-1,-induced ICAM-1 gene expression, NF-,B transcriptional activity, I,B phosphorylation/degradation, and NF-,B DNA binding activity in IEC. Moreover, guggulsterone strongly blocked IKK activity. Administration of guggulsterone significantly reduced the severity of DSS-induced murine colitis as assessed by clinical disease activity score, colon length, and histology. Furthermore, tissue upregulation of I,B and IKK phosphorylation induced by DSS was attenuated in guggulsterone-treated mice. Conclusion: Guggulsterone blocks NF-,B signaling pathway by targeting IKK complex in IEC and attenuates DSS-induced acute murine colitis, which suggests that guggulsterone could be an attractive therapeutic option in the treatment of IBD. [source] Role of NK1.1+ and AsGm-1+ cells in oral immunoregulation of experimental colitisINFLAMMATORY BOWEL DISEASES, Issue 2 2003Shivti Trop Abstract NK1.1 and AsGm-1 expressing cells play a role in immunomodulation. Our purpose was to determine the role of NK1.1+ and AsGm-1+ expressing cells in the inflammatory/tolerance paradigm in experimental colitis. Oral tolerance towards colitis-extracted proteins had previously been shown to alleviate experimental colitis. Colitis was induced in C57/B6 mice by intracolonic instillation of trinitrobenzenesulfonic acid (TNBS). Oral tolerance was induced via five oral doses of proteins extracted from TNBS-colitis colonic wall. Clinical, macroscopic, and microscopic scores were used for colitis assessment. To evaluate the putative role of AsGm-1 in tolerance induction, depletion of AsGm-1 expressing cells was performed. To evaluate the mechanism of tolerance induction, liver-associated NKT lymphocytes were harvested 14 days following tolerance induction, and cultured with concanavalin A (con A) and colitis-extracted proteins. T cell subsets were measured by flow cytometry. Cytokine expression was measured by intracellular staining and enzyme-linked immunosorbent assay (ELISA). Orally tolerized mice exhibited significant alleviation of the clinical, macroscopic, and microscopic parameters of colitis, with increased CD4+IL4+/CD4+IFN,+ lymphocyte ratio, increased IL-4, and decreased IFN, and IL-12 serum levels. In contrast, orally fed mice that were AsGm-1 depleted showed evidence of severe colitis. These mice exhibited significant decreased CD4+IL4+/CD4+IFN,+ ratios, and an increase in IFN, and IL-12, with decreased IL-4 levels. NKT cells harvested from tolerized mice secreted high levels of antiinflammatory cytokines. In contrast, in nontolerized mice, NKT cells mainly secreted proinflammatory cytokines. In a tolerized environment, both NK1.1 and AsGm-1 expressing cells are essential for disease alleviation. In contrast, in a nontolerized environment, AsGm-1 expressing cells support an antiinflammatory immune paradigm, while NKT lymphocytes support a proinflammatory shift. [source] On the capillary stress tensor in wet granular materialsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 10 2009L. Scholtès Abstract This paper presents a micromechanical study of unsaturated granular media in the pendular regime, based on numerical experiments using the discrete element method, compared with a microstructural elastoplastic model. Water effects are taken into account by adding capillary menisci at contacts and their consequences in terms of force and water volume are studied. Simulations of triaxial compression tests are used to investigate both macro and micro-effects of a partial saturation. The results provided by the two methods appear to be in good agreement, reproducing the major trends of a partially saturated granular assembly, such as the increase in the shear strength and the hardening with suction. Moreover, a capillary stress tensor is exhibited from capillary forces by using homogenization techniques. Both macroscopic and microscopic considerations emphasize an induced anisotropy of the capillary stress tensor in relation with the pore fluid distribution inside the material. Insofar as the tensorial nature of this fluid fabric implies shear effects on the solid phase associated with suction, a comparison has been made with the standard equivalent pore pressure assumption. It is shown that water effects induce microstructural phenomena that cannot be considered at the macro level, particularly when dealing with material history. Thus, the study points out that unsaturated soil stress definitions should include, besides the macroscopic stresses such as the total stress, the microscopic interparticle stresses such as the ones resulting from capillary forces, in order to interpret more precisely the implications of the pore fluid on the mechanical behaviour of granular materials. Copyright © 2009 John Wiley & Sons, Ltd. [source] Multi-scale domain decomposition method for large-scale structural analysis with a zooming technique: Application to plate assemblyINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 4 2009A. Mobasher Amini Abstract This article is concerned with a multi-scale domain decomposition method (DDM), based on the FETI-DP solver, for large-scale structural elastic analysis and suited to problems that exhibit structural heterogeneities, such as plate assemblies in the presence of structural details. In this approach once a partition of the global fine mesh into subdomains has been performed (all subdomains possess a fine mesh) and to optimize the computational time, the fine mesh is preserved only in the zones of interest (with local phenomena due to discontinuity, hole, etc.) while the remaining subdomains are replaced by numerical homogenized coarse elements. Indeed, the multi-scale aspect is introduced by the description of subdomains with either a fine or a coarse scale mesh. As a result, an extension of the FETI-DP DDM is proposed in this article (called herein FETI-DP micro,macro) that allows the simultaneous usage of different discretizations: fine (microscopic) mesh for subdomains in zones of interest and coarse (macroscopic or homogenized) mesh for the complementary part of the structure. Using this strategy raises the problem of the determination of the stiffness of coarse subdomains, and of the incompatible finite element connection between fine and coarse subdomains. Two approaches (collocation and Mortar) are presented and compared. The article ends with patch tests and some numerical examples in 2D and 3D. The obtained numerical results exemplify the efficiency and capability of the FETI-DP micro,macro approach and reveal that the Mortar approach is more accurate, at constant cost, than the collocation approach. Copyright © 2009 John Wiley & Sons, Ltd. [source] A second-order homogenization procedure for multi-scale analysis based on micropolar kinematicsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2007Ragnar Larsson Abstract The paper presents a higher order homogenization scheme based on non-linear micropolar kinematics representing the macroscopic variation within a representative volume element (RVE) of the material. On the microstructural level the micro,macro kinematical coupling is introduced as a second-order Taylor series expansion of the macro displacement field, and the microstructural displacement variation is gathered in a fluctuation term. This approach relates strongly to second gradient continuum formulations, presented by, e.g. Kouznetsova et al. (Int. J. Numer. Meth. Engng 2002; 54:1235,1260), thus establishing a link between second gradient and micropolar theories. The major difference of the present approach as compared to second gradient formulations is that an additional constraint is placed on the higher order deformation gradient in terms of the micropolar stretch. The driving vehicle for the derivation of the homogenized macroscopic stress measures is the Hill,Mandel condition, postulating the equivalence of microscopic and macroscopic (homogenized) virtual work. Thereby, the resulting homogenization procedure yields not only a stress tensor, conjugated to the micropolar stretch tensor, but also the couple stress tensor, conjugated to the micropolar curvature tensor. The paper is concluded by a couple of numerical examples demonstrating the size effects imposed by the homogenization of stresses based on the micropolar kinematics. Copyright © 2006 John Wiley & Sons, Ltd. [source] Simulation of shockwave propagation with a thermal lattice Boltzmann modelINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2003ShiDe Feng Abstract A two-dimensional 19-velocity (D2Q19) lattice Boltzmann model which satisfies the conservation laws governing the macroscopic and microscopic mass, momentum and energy with local equilibrium distribution order O(u4) rather than the usual O(u3) has been developed. This model is applied to simulate the reflection of shockwaves on the surface of a triangular obstacle. Good qualitative agreement between the numerical predictions and experimental measurements is obtained. As the model contains the higher-order terms in the local equilibrium distribution, it performs much better in terms of numerical accuracy and stability than the earlier 13-velocity models with the local equilibrium distribution accurate only up to the second order in the velocity u. Copyright © 2003 John Wiley & Sons, Ltd. [source] Nanolayered Carbon/Silica Superstructures via Organosilane AssemblyADVANCED MATERIALS, Issue 6 2008Huisheng Peng Nanolayered carbon/silica superstructures with tunable morphologies (tubes, fibers, or spheres) and sizes (micro-sized or macroscopic) were synthesized by self-assembly of perylenedidimide-bridged silsesquioxane through an easy sol-gel process followed by carbonization. The derived nanocomposite materials show interesting electrical properties, i.e., the conductivity increases exponentially with temperature. 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