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Microscopic
Kinds of Microscopic Terms modified by Microscopic Selected AbstractsANALYSIS OF NASRID POLYCHROME CARPENTRY AT THE HALL OF THE MEXUAR PALACE, ALHAMBRA COMPLEX (GRANADA, SPAIN), COMBINING MICROSCOPIC, CHROMATOGRAPHIC AND SPECTROSCOPIC METHODS,ARCHAEOMETRY, Issue 4 2009C. CARDELL The pigments, binders and execution techniques used by the Nasrids (1238,1492) to polychrome carpentry in the Hall of the Mexuar Palace at the Alhambra (Granada, Spain) were studied using optical microscopy, scanning electron microscopy with EDX analysis, selective staining techniques and gas chromatography , mass spectrometry. This pioneering investigation presents the first results of a research project devoted to filling gaps in the knowledge of Nasrid art, traditionally approached by stylistic studies. Moreover, it is essential for the polychromy conservation of the studied artworks, and will help to clarify historical and painting uncertainties in the Alhambra monument. The palette consists of a limited range of colours: white (lead-base pigment), red (cinnabar and red lead), blue (lapis lazuli), black (carbon-based) and false gold (golden tin). Tempera grassa was the painting technique identified. Two types of grounds were used: (i) gypsum in calligraphy decoration for the false gold technique, and (ii) synthetic minium in geometric drawings in carpentry. Organic insulating layers of linseed oil were used between paint strata. Artists applied synthetic minium to protect the wood (Juglans regia and conifer) against attack by xylophages. To lighten the surface darkened by this ground layer, powdered tin was added to achieve a metallic lustre. [source] A Microscopic and Biomechanical Study of Skin and Soft Tissue After Repeated ExpansionDERMATOLOGIC SURGERY, Issue 1 2009RAN HUO MD BACKGROUND Conventional expansion inadequately restores damaged skin for patients with large areas of skin deficiency or who lack sources of normal skin. These patients require repeated skin expansions, but little is known about the outcomes of this procedure. OBJECTIVE To evaluate the microscopic changes and biomechanical properties of skin and soft tissue after repeated expansion. MATERIALS AND METHODS We prepared three groups of six pigs each: a conventional expansion group, a repeated expansion group, and a blank nonsurgical control group. We measured histology, ultrastructure, basic fibroblast growth factor (bFGF), stress,strain, stress relaxation, and stress strength. RESULTS Skin obtained after conventional expansion and repeated expansion was basically healthy, but the microscopic and biomechanical properties differed from those of nonexpanded skin, especially in the repeated expansion group. CONCLUSION Repeated skin expansion involves growth under stress, simultaneous injuries, and further repairs, with fibers showing more injury signs than cells. This article describes the microscopic changes and biomechanical properties that occur after repeated expansion. [source] Fat and protein contents, acidity and somatic cell counts in bulk milk of Holstein cows in the Khorasan Razavi Province, IranINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 1 2009MASOUD NAJAF NAJAFI Relationships between total bulk milk somatic cell score (SCS) and milk fat and protein contents and acidity were investigated in the Khorasan Razavi Province, a region that contributes 6.83% of total milk production in Iran. A total of 1476 samples were analysed. Data were obtained by randomly collecting 123 samples of bulk tank milk from 41 dairy farms during April 2006 to March 2007, every month. Milk was analysed for titratable acidity, protein and fat contents and somatic cell counts (direct microscopic cell count and with Somatos, Russia). Microscopic and Somatos somatic cell counts were comparable. Results showed that the season of raw milk production did not have a significant effect on acidity. Milk fat content increased gradually from spring to winter and there were significant differences (P < 0.05) between spring and other seasons. Higher levels of milk protein fractions were observed during the autumn and winter than in other seasons. The highest total bulk milk somatic cell counts were observed in July. Total bulk milk SCS had significant effects (P < 0.05) on acidity and fat and protein contents. Moreover, the level of acidity and fat in milk decreased with increasing SCS. A significant positive relationship was observed between total bulk milk SCS and the protein content of milk. Elevated SCS were associated with lowered milk quality in Holsteins in the Khorasan Razavi Province. [source] Mucosa-associated lymphoid tissue lymphoma of the rectum that regressed spontaneouslyJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 3 2000Ryuta Takenaka Abstract We report a case of mucosa-associated lymphoid tissue (MALT) lymphoma of the rectum that regressed spontaneously. A 76-year-old man visited our hospital because of positive faecal occult blood testing. Colonoscopic examination revealed a slightly yellowish protruded lesion with a grooved depression in the lower rectum and two flat elevations in the upper rectum. Microscopic and immunohistological studies led to a diagnosis of MALT lymphoma. As the patient exhibited severe renal dysfunction and angina pectoris, the lesions were left untreated. Three months later, the protruded lesion became flat and the other lesions became unclear. He was followed up closely with endoscopy, but no relapse of these lesions was detected 19 months after the diagnosis. © 2000 Blackwell Science Asia Pty Ltd [source] Crystal Shape Characterisation of Dry Samples using Microscopic and Dynamic Image AnalysisPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 4 2009Kumar Patchigolla Abstract A standard method to determine particle shape and size is by image analysis. This paper addresses microscopic image analysis (semi-automated) investigations of two different organic crystalline chemicals generated by batch cooling crystallisation. The results generated from microscopic image analysis were compared with data obtained by dynamic image analysis (automated) because very few contributions are available in the open literature. The chemical systems were polymorphic L-glutamic acid which crystallises into , (prismatic) or , (needle) form and the non-polymorphic mono sodium glutamate which crystallises into needles. The images from these techniques were processed to generate information on crystal shape and size. It has been observed that shape effects can distort the size obtained in size characterization studies. In this study, comparisons were made of processing time, number of crystals and accuracy between microscopic and dynamic image analysis. For representative microscopic image analysis, 5000 crystals were analysed in an average of eight hours while several hundred thousand crystals were processed using dynamic image analysis within 15 minutes. Using the parameters D10, D50, D90, span and aspect ratio for statistical comparison, it was found that the results obtained for D50 by the two techniques were comparable and in accordance with other measurements (laser diffraction spectroscopy and ultrasonic attenuation spectroscopy) even though these non-spherical particles had different orientations during measurement by the two methods. However, substantial differences in span of the distribution and aspect ratio were returned by the two techniques. [source] Microscopic and macroscopic modelling of foamsPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003Stefan Diebels Prof. Dr.-Ing. The macroscopic behaviour of foams is influenced by the size and structure of the pores. Therefore, a Cosserat theory is motivated by a micromechanical beam model. A homogenization strategy is applied to the micromechanical model leading to results that are comparable to the predictions of the macroscopic Cosserat model. [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] Microscopic and Spectroscopic Observations in the Bio-Nanoworld,CHEMPHYSCHEM, Issue 9-10 2009Peter Hinterdorfer Prof. Abstract Biophysics in Linz: In February biophysicists from across the world converged on Linz for two biophysical conferences. The city which is the Cultural Capital of Europe 2009, provided the perfect environment for fruitful discussions on single-molecule techniques in biophysics, bio-nanotechnology, cell biology, and drug discovery. [source] XRD, thermal, FTIR and SEM studies on gel grown ,-glycine crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2007E. Ramachandran Abstract Glycine is the smallest among amino acids. The polymorphs, ,- and ,-forms of glycine were crystallized in silica gel by reduction of solubility method. The grown crystals were characterized by single crystal X-ray diffraction studies and density determination. Fourier transform infrared spectroscopic studies and thermogravimetric analysis of ,-glycine were also conducted. Morphological and scanning electron microscopic (SEM) studies were also made and compared with the crystal packing. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Gel growth and characterization of , -DL-methionineCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2006E. Ramachandran Abstract DL-Methionine [C5H11NO2S] is one of the essential amino acids in humans. It has two crystalline forms, viz., ,- and ,- methionine. In the present study, , - form is crystallized in silica gel; under suitable pH conditions by single diffusion method. The grown crystals were characterized by density measurement and single crystal X-ray diffraction. Fourier transform infrared (FTIR) spectroscopic studies, thermal analysis and scanning electron microscopic (SEM) studies were also made as part of the structural studies. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A Microscopic and Biomechanical Study of Skin and Soft Tissue After Repeated ExpansionDERMATOLOGIC SURGERY, Issue 1 2009RAN HUO MD BACKGROUND Conventional expansion inadequately restores damaged skin for patients with large areas of skin deficiency or who lack sources of normal skin. These patients require repeated skin expansions, but little is known about the outcomes of this procedure. OBJECTIVE To evaluate the microscopic changes and biomechanical properties of skin and soft tissue after repeated expansion. MATERIALS AND METHODS We prepared three groups of six pigs each: a conventional expansion group, a repeated expansion group, and a blank nonsurgical control group. We measured histology, ultrastructure, basic fibroblast growth factor (bFGF), stress,strain, stress relaxation, and stress strength. RESULTS Skin obtained after conventional expansion and repeated expansion was basically healthy, but the microscopic and biomechanical properties differed from those of nonexpanded skin, especially in the repeated expansion group. CONCLUSION Repeated skin expansion involves growth under stress, simultaneous injuries, and further repairs, with fibers showing more injury signs than cells. This article describes the microscopic changes and biomechanical properties that occur after repeated expansion. [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] Fine-needle aspiration of synovial sarcoma: Criteria for diagnosis: Retrospective reexamination of 37 cases, including ancillary diagnostics.DIAGNOSTIC CYTOPATHOLOGY, Issue 5 2003A Scandinavian sarcoma group study Abstract The cytologic criteria of synovial sarcoma in fine-needle aspirates were defined by a retrospective examination of 37 primary tumors. Irrespective of subtype, a typical pattern at low power was found, provided the yield was rich. The typical pattern was a mixture of dispersed cells with the presence of striped nuclei and cell-tight tumor tissue fragments with irregular borders. Often a branching network of vessels was present in the fragments, imitating a true vascular tumor. Except in poorly differentiated synovial sarcomas, the tumor cells were, small to medium in size, with rounded, ovoid, or fusiform bland nuclei with inconspicuous nucleoli. In the biphasic variant, small glandular- or acinar-like structures were present, although not in all cases. In the poorly differentiated type, however, the cellular pleomorphism was marked with the presence of cells with irregular nuclei and rhabdomyoblast-like cells, corresponding to the pleomorphic variant. The Ewing's sarcoma-like and the atypical spindle cell variants of poorly differentiated synovial sarcoma were not diagnosed in the material. An unequivocal diagnosis of sarcoma is possible when the yield is rich. However, ancillary diagnostics are necessary for a correct diagnosis, to avoid important pitfalls, such as other sarcomas with bland tumor cells and vessel-rich tumor fragments, in particular, solitary fibrous tumor and true hemangiopericytoma. Electron microscopic and/or molecular genetic analyses were better diagnostic adjuncts than immunocytochemistry. Diagn. Cytopathol. 2003;28:232,238. © 2003 Wiley-Liss, Inc. [source] PNET-like features of synovial sarcoma of the lung: A pitfall in the cytologic diagnosis of soft-tissue tumorsDIAGNOSTIC CYTOPATHOLOGY, Issue 4 2001Pascale Hummel M.D. Abstract Fine-needle aspiration (FNA) cytology of soft-tissue tumors is evolving. As more experience is gained, we are becoming aware of potential pitfalls. We describe 2 cases of synovial sarcoma of the lung, primary and metastatic, in patients who had FNA biopsy performed on a lung mass. The cytologic smears showed extremely cellular groups of malignant small round cells, intersected by small blood vessels, with numerous loose single cells, in a background of macrophages and mature lymphocytes. The tumors displayed monomorphic cells forming rosettes and displaying occasional mitoses. A diagnosis of neuroendocrine tumor/primitive neuroepithelial tumor (PNET) was suspected. Furthermore, this suspicion was supported by immunohistochemical stains, which showed positivity for a neuroendocrine marker, Leu 7 (case 1), and for a neural marker, CD 99 (O 13 or HBA 71) (both cases); and negativity for cytokeratins (case 1). The resection specimen of case 1 had mostly tightly packed small round cells, with occasional rosettes, similar to the FNA biopsy, and focal areas composed of spindle cells, organized in a focal fibrosarcoma-like and hemangiopericytoma-like pattern. A balanced translocation between chromosomes X and 18, demonstrated by both karyotyping and fluorescent in situ hybridization (FISH), enabled us to make a diagnosis of synovial sarcoma, which was histologically classified as poorly differentiated. Case 2 was a metastatic biphasic synovial sarcoma of the arm, with a prominent epithelial component. Synovial sarcoma, when composed mainly of small round cells on cytologic smears, is a great mimicker of neuroendocrine/PNET tumors, with light microscopic and immunohistochemical overlap. Awareness of this potential pitfall may aid in preventing a misdiagnosis. Its recognition is of major concern, especially for the poorly differentiated variant, because it is associated with a worse prognosis. Diagn. Cytopathol. 24:283,288, 2001. © 2001 Wiley-Liss, Inc. [source] Contrasting microcystin production and cyanobacterial population dynamics in two Planktothrix -dominated freshwater lakesENVIRONMENTAL MICROBIOLOGY, Issue 10 2005Ingmar Janse Summary Microcystin concentrations in two Dutch lakes with an important Planktothrix component were related to the dynamics of cyanobacterial genotypes and biovolumes. Genotype composition was analysed by using denaturing gradient gel electrophoresis (DGGE) profiling of the intergenic transcribed spacer region of the rrn operon (rRNA-ITS), and biovolumes were measured by using microscopy. In Lake Tjeukemeer, microcystins were present throughout summer (maximum concentration 30 µg l,1) while cyanobacterial diversity was low and very constant. The dominant phototroph was Planktothrix agardhii. In contrast, Lake Klinckenberg showed a high microcystin peak (up to 140 µg l,1) of short duration. In this lake, cyanobacterial diversity was higher and very dynamic with apparent genotype successions. Several genotypes derived from DGGE field profiles matched with genotypes from cultures isolated from field samples. The microcystin peak measured in Lake Klinckenberg could be confidently linked to a bloom of Planktothrix rubescens, as microscopic and genotypic analysis showed identity of bloom samples and a toxin-producing P. rubescens culture. Toxin-producing genotypes were detected in the microbial community before they reached densities at which they were detected by using microscopy. Cyanobacterial biovolumes provided additional insights in bloom dynamics. In both lakes, the microcystin content per cell was highest at the onset of the blooms. Our results suggest that while genotypic characterization of a lake can be valuable for detection of toxic organisms, for some lakes a monitoring of algal biomass has sufficient predictive value for an assessment of toxin production. [source] Cell surface analysis of the lipid-discharging obligate hydrocarbonoclastic species of the genus AlcanivoraxEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 6 2010Alvin Brian Lange Abstract This study presents novel information useful for addressing the question how species of the genus Alcanivorax discharge triacylglycerols (TAG) and/or wax esters (WE). The observed structures were referred as "blebs" according to Gauthier et al.1 to avoid confusion with other discharging phenomena. The cells were aerobically cultivated on solid media and not in liquid media to maintain the cells in the native state, and were investigated by transmission electron microscopic (TEM) and scanning electron microscopic (SEM) methods to document the surface structures of the cells. The phenomenon of lipid export could be allocated to three phases: phase I: protrusion formation of the cell membrane occurred; phase II: discharging progressed further with blebs becoming larger; and phase III: the blebs at the cell surface were separated from the cells. Using freeze-fracture micrographs by TEM, vesicle experiments and TLC, we have shown that the blebs contained TAGs and WEs. The results shown in this study will support further research to unravel the unknown discharging mechanism. In addition, the formation of an extensive extracellular matrix was observed by SEM. [source] Glutamate transporter expression in astrocytes of the rat dentate gyrus following lesion of the entorhinal cortexEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2001C. Hein Abstract The glutamate transporters GLT-1 and GLAST localized in astrocytes are essential in limiting transmitter signalling and restricting harmful receptor overstimulation. To show changes in the expression of both transporters following lesion of the entorhinal cortex (and degeneration of the glutamatergic tractus perforans), quantitative microscopic in situ hybridization (ISH) using alkaline-phosphatase-labelled oligonucleotide probes was applied to the outer molecular layer of the hippocampal dentate gyrus of rats (termination field of the tractus perforans). Four groups of rats were studied: sham-operated controls, and animals 3, 14 and 60 days following unilateral electrolytic lesion of the entorhinal cortex. The postlesional shrinkage of the terminal field of the perforant path, ipsilateral to the lesion side, was determined and considered in the evaluation of quantitative ISH data. Statistical analysis revealed that ipsilateral to the lesion side there was a significant decrease of the GLT-1 mRNA at every postlesional time-point and of the GLAST mRNA at 14 and 60 days postlesion. The maximal decrease was ,,45% for GLT-1 and ,,35% for GLAST. In the terminal field of the perforant path contralateral to the lesion side, no significant changes of ISH labelling were measured. The results were complemented by immunocytochemical data achieved using antibodies against synthetic GLT-1 and GLAST peptides. In accordance with ISH results, there was an obvious decrease of GLT-1 and GLAST immunostaining in the terminal field of the perforant path ipsilateral to the lesion side. From these data we conclude that, following a lesioning of the entorhinal cortex, the loss of glutamatergic synapses in the terminal field of the perforant path resulted in a strong downregulation of glutamate transporters in astrocytes. The decrease of synaptically released glutamate or of other neuronal factors could be involved in this downregulation. [source] Stress-Dependent Elastic Properties of Porous Microcracked Ceramics,ADVANCED ENGINEERING MATERIALS, Issue 12 2009Irina Pozdnyakova Abstract Although ceramics are considered linear elastic materials, we have observed a non-linear pseudo-elastic behavior in porous cellular microcracked ceramics such as , -eucryptite. This is attributed to the evolution of microstructure in these materials. This behavior is particularly different from that of non-microcracked ceramics such as silicon carbide. It is shown that in microcracked materials two processes, namely stiffening and softening, always compete when a compressive external load is applied. The first regime is attributed to microcrack closure, and the second to microcracks opening, i.e. to a damage introduced by the applied stress. On the other hand rather a continuous damage is observed in the non-microcracked case. A comparison has been done between the microscopic (as measured by neutron diffraction) and the macroscopic stress-strain response. Also, it has been found that at constant load a significant strain relaxation occurs, which has two timescales, possibly driven by the two phenomena quoted above. Indeed, no such relaxation is observed for non-microcracked SiC. Implications of these findings are discussed. [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] Comparative single-strand conformation polymorphism (SSCP) and microscopy-based analysis of nitrogen cultivation interactive effects on the fungal community of a semiarid steppe soilFEMS MICROBIOLOGY ECOLOGY, Issue 2-3 2001Jennifer L. Lowell Abstract The effects of nitrogen accretion on fungal diversity and community structure in early-seral (cultivated) and native (uncultivated) shortgrass steppe soils were evaluated using single-strand conformation polymorphism (SSCP) and microscopy in a comparative experiment. Selected haplotypes generated from fungal 18S gene fragments were also sequenced for species identification. Microscopy-based analyses showed significantly shorter fungal hyphal lengths in the early-seral control plots in comparison with the native control plots (P<0.0003), independent of nitrogen addition. Although diversity indices did not show significant differences between the plots, SSCP analyses indicated that fungal community structure differed in the native and early-seral control sites. In nitrogen-amended sites, gene sequences from dominant haplotypes indicated a shift to a more common nitrogen-impacted fungal community. While nitrogen amendments appear to be more important than cultivation in influencing these soil fungal communities, hyphal lengths were only decreased due to cultivation. The use of microscopic and molecular techniques, as carried out in this study, provided integrative information concerning fungal community responses to wide spread stresses being imposed globally on terrestrial ecosystems, that is not provided by the individual techniques. [source] ,Defence lignin' and hydroxycinnamyl alcohol dehydrogenase activities in wounded Eucalyptus gunniiFOREST PATHOLOGY, Issue 2 2003S. Hawkins Summary To learn more about lignin formation in response to wounding in trees, we adopted two complementary approaches: (1) microscopic and histochemical studies of the wound response in 3.5-month-old Eucalyptus gunnii plantlets and (2) biochemical investigations of hydroxycinnamyl alcohol dehydrogenase activities in wounded 6-year-old, field-grown E. gunnii trees. The first approach revealed that a barrier zone was formed in response to wounding in both ground tissues (cortex barrier and pith reaction zone) and vascular tissues. The barrier zone was barely detectable after 24 h but well-developed 7 days after wounding. Microscopic analyses indicated that the barrier zone was formed by the reinforcement of cell walls with ,lignin-like material' in both ground tissues and vascular tissue, and that, in addition, the lumen of certain xylem cells (vessels and fibres) were blocked by the deposition of polymeric phenolic material. Histochemical characterization revealed that the lignin-like material (,defence lignin') deposited in ground tissue cell walls and xylem cell blockages was poor in syringyl (S-type) lignin units and therefore differed from the usual mixed guaiacyl,syringyl (G,S) lignin unit composition of E. gunnii developmental lignin. In contrast, S-type lignin appeared to be deposited in the cell walls of immature developing secondary xylem cells at a stage when the cell walls of comparable cells from unwounded control stems contained lignin poor in syringyl units. The second approach indicated that two different types of cinnamyl alcohol dehydrogenase activity are induced, and apparently regulated differentially, in response to wounding in E. gunnii trees. Coniferyl alcohol dehydrogenase activity was induced immediately and continued to increase throughout the first 15 days of the 17-day experimental period, while sinapyl alcohol dehydrogenase activity was first detected at 8 days after wounding and continued to increase throughout the experimental period. The biological roles of the two alcohol dehydrogenase activities are discussed in relation to the formation of defence lignin versus developmental lignin in trees. Résumé Afin d'approfondir nos connaissances concernant la formation de lignine en réponse aux blessures chez les arbres, nous avons utilisé deux approches complémentaires: (1) des études microscopiques et histochimiques de la réponse à la blessure chez les plantules d'Eucalyptus gunniiâgées de 3 mois et demi, et (2) des analyses biochimiques des activités alcools hydroxycinnamyliques déshydrogénases chez les arbres âgés de 6 ans blessés au champ. L'utilization de la première approche a révélé qu'une barrière physique se forme en réponse à la blessure aux niveaux des tissus vasculaires, de la moelle, et des tissus externes au phloème. A 24 h après la blessure, cette barrière est peu développée mais elle est bien formée après 7 jours. Les analyses microscopiques et histochimiques ont indiqué que les parois cellulaires au niveau de la barrière sont renforcées par un composé semblable à la lignine (,lignin-like material'). De plus, les lumens de plusieurs cellules xylémiennes (vaisseaux et fibres) sont bouchées par le dépôt d'un composé polymérique de nature phénolique. Les caractérizations histochimiques ont indiqué que le ,lignin-like material' (lignine de défense) déposé dans les parois cellulaires de la moelle et des tissus externes au phloème, et dans les lumens des cellules xylemiennes, contient peu d'unités syringyles (type-S). En conséquence, cette ,lignine de défense' se distingue de la ,lignine de développement' typique d'E. gunnii, qui est composée d'unités guaiacyles (type-G) et d'unités syringyles (type-S). En revanche chez les plantules blessées, des unités syringyles sont déposées dans les parois des cellules immatures du xylème à un stade où les cellules comparables des plantules témoins ne contiennent que très peu d'unités syringyles. La deuxième approche a indiqué que deux activités alcools cinnamyliques déshydrogénases différentes sont induites, et régulées d'une façon différencielle, en réponse à la blessure chez les arbres d'E. gunnii. L'activité alcool coniférylique déshydrogénase est induite rapidement et continue d'augmenter pendant les 15 premiers jours de la période expérimentale de 17 jours, tandis que l'activité alcool sinapylique déshydrogénase est seulement détectée à 8 jours après la blessure et continue d'augmenter le long de la période expérimentale. Les rôles biologiques potentiels de ces deux activités alcools déshydrogénases sont discutés en relation avec la formation de la lignine de défense et avec la lignine de développement chez les arbres. Zusammenfassung Zur Untersuchung der Ligninbildung nach Verletzungen bei Bäumen wurden zwei sich ergänzende Forschungsansätze gewählt: 1. Mikroskopische und histochemische Untersuchungen der Wundreaktion an Jungpflanzen (3,5 Monate alt) von Eucalyptus gunnii und 2. Biochemische Untersuchungen der Hydroxycinnamylalkohol-Dehydrogenase-Aktivität bei verletzten, sechs Jahre alten E. gunnii -Bäumen im Freiland. Der erste Ansatz zeigte, dass eine Barrierezone als Antwort auf die Verletzung sowohl in beiden Grundgeweben (Cortex-Barriere und Reaktionszone im Mark) als auch in den Leitgeweben gebildet wird. Die Barrierezone war 24 Stunden nach der Verletzung gerade erkennbar, nach sieben Tagen war sie gut entwickelt. Die mikroskopische Untersuchung zeigte, dass die Barrierezone durch Verstärkung der Zellwände mit ,,ligninartigem Material,, im Grund- und Leitgewebe gebildet wurde, und dass zusätzlich das Lumen gewisser Xylemzellen (Gefässe und Fasern) durch Ablagerung von polymerem phenolischem Material verschlossen wurde. Die histochemische Analyse ergab, dass das ligninartige Material (,,Abwehrlignin,,), das in den Zellwänden des Grundgewebes und in den Lumina der Xylemzellen abgelagert wurde, geringe Mengen an Syringyl-(S-Typ)-Lignineinheiten enthielt und sich somit von der normalen Guaiacyl-Syringyl(G-S)-Komposition des Lignins von E. gunnii unterschied. Das S-Typ-Lignin wurde offenbar in den Zellwänden sich entwickelnder sekundärer Xylemzellen abgelagert. Diese Einlagerung erfolgte in einem Stadium, in dem die Zellwände der vergleichbaren Zellen in unverletzten Kontrollstämmen Lignin mit geringem Syringylgehalt enthielten. Der zweite Versuchsansatz zeigte, dass als Reaktion auf die Verletzung zwei verschiedene Arten von Cinnamylalkohol-Dehydrogenase-Aktivitäten induziert und offensichtlich unterschiedlich reguliert werden. Die Aktivität der Coniferyl-Alkohol-Dehydrogenase wurde sofort induziert und sie nahm während 15 Tagen der 17tägigen Versuchsperiode stetig zu, während die Aktivität der Sinapyl-Dehydrogenase erstmals 8 Tage nach der Verletzung nachweisbar war und dann während der gesamten Versuchsperiode anstieg. Die biologische Bedeutung der beiden Alkoholdehydrogenase-Aktivitäten werden in Bezug auf die Bildung von Abwehr-Lignin im Vergleich zur normalen Ligninbildung in Bäumen diskutiert. [source] "The probable industrial origin of archaeological daub at an Iron Age site in northeast Thailand" (Parr and Boyd, 2002): A comment on the inappropriate application of geophysical and geochemical techniques to an archaeological questionGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2003Maria Cotter Parr and Boyd (2002) used colorimetric analysis in combination with geophysical and geochemical techniques to estimate firing temperatures for archaeological daub from an Iron Age site in Thailand. They suggest that the daub was fired at high temperatures and, therefore, is indicative of kiln utilization and increased industrialization during that period in Thailand. They argue that the adoption of a multimethod analytical approach in which the combination of data derived from ICP-MS, X-ray diffraction, and magnetic susceptibility analyses of daub samples, coupled with microscopic and macroscopic examination of samples, enhances the accuracy of their interpretations. While they should be commended for attempting to substantiate their claims using many geophysical and geochemical techniques, their arguments are flawed by the misapplication of the techniques described and/or over-interpretation of the data generated by such techniques. Therefore, Parr and Boyd's (2002:285) point about methodology ("that the combined interpretation of independent measures provides a better estimate of the original firing temperatures of the archaeological material than has hitherto been possible") is made redundant by the lack of scientific rigor applied to the independent measures used for this study. © 2003 Wiley Periodicals, Inc. [source] Abrasiveness Testing, Quo Vadis?GEOMECHANICS AND TUNNELLING, Issue 1 2008A Commented Overview of Abrasiveness Testing Methods The growing economic pressure on tunnelling and mining operations has lead to an increasing importance of investigation methods for assessing the abrasiveness of rock and soil. Such investigations can be based on a wide variety of testing procedures and standards covering a wide span of scale, ranging from real-scale tests on site to model tests with simplified tools and microscopic and chemical analyses of rocks and minerals. This paper gives an overview over some of the most important procedures, technical aspects of their application, classification of testing results and the current state of experience. Abrasivitätstest, quo vadis? Ein kommentierter Überblick über Abrasivitäts-Testverfahren Der stetig zunehmende wirtschaftliche Druck auf Tunnelbau und Rohstoffgewinnung führt zu einer steigenden Bedeutung von Untersuchungsverfahren zur Bewertung der Abrasivität von Fest- und Lockergesteinen. Derartige Untersuchungen können mit einer Vielzahl von Verfahren durchgeführt werden, die von Untersuchungen vor Ort im Realmaßstab über Modellversuche mit vereinfachten Werkzeugen bis hin zu mikroskopischen oder chemischen Untersuchungen eine weite Bandbreite an Untersuchungsmaßstäben einschließen. Der vorliegende Beitrag soll einen Überblick über die derzeit wesentlichsten Untersuchungsverfahren, versuchstechnische Aspekte, angewandte Klassifizierungsschlüssel sowie Einsatzerfahrungen mit den jeweiligen Verfahren geben. [source] Spectral-element simulations of wave propagation in porous mediaGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2008Christina Morency SUMMARY We present a derivation of the equations describing wave propagation in porous media based upon an averaging technique which accommodates the transition from the microscopic to the macroscopic scale. We demonstrate that the governing macroscopic equations determined by Biot remain valid for media with gradients in porosity. In such media, the well-known expression for the change in porosity, or the change in the fluid content of the pores, acquires two extra terms involving the porosity gradient. One fundamental result of Biot's theory is the prediction of a second compressional wave, often referred to as ,type II' or ,Biot's slow compressional wave', in addition to the classical fast compressional and shear waves. We present a numerical implementation of the Biot equations for 2-D problems based upon the spectral-element method (SEM) that clearly illustrates the existence of these three types of waves as well as their interactions at discontinuities. As in the elastic and acoustic cases, poroelastic wave propagation based upon the SEM involves a diagonal mass matrix, which leads to explicit time integration schemes that are well suited to simulations on parallel computers. Effects associated with physical dispersion and attenuation and frequency-dependent viscous resistance are accommodated based upon a memory variable approach. We perform various benchmarks involving poroelastic wave propagation and acoustic,poroelastic and poroelastic,poroelastic discontinuities, and we discuss the boundary conditions used to deal with these discontinuities based upon domain decomposition. We show potential applications of the method related to wave propagation in compacted sediments, as one encounters in the petroleum industry, and to detect the seismic signature of buried landmines and unexploded ordnance. [source] Axonal integrity in the absence of functional peroxisomes from projection neurons and astrocytesGLIA, Issue 13 2010Astrid Bottelbergs Abstract Ablation of functional peroxisomes from all neural cells in Nestin-Pex5 knockout mice caused remarkable neurological abnormalities including motoric and cognitive malfunctioning accompanied by demyelination, axonal degeneration, and gliosis. An oligodendrocyte selective Cnp-Pex5 knockout mouse model shows a similar pathology, but with later onset and slower progression. Until now, the link between these neurological anomalies and the known metabolic alterations, namely the accumulation of very long-chain fatty acids (VLCFA) and reduction of plasmalogens, has not been established. We now focused on the role of peroxisomes in neurons and astrocytes. A neuron-specific peroxisome knockout model, NEX-Pex5, showed neither microscopic nor metabolic abnormalities indicating that the lack of functional peroxisomes within neurons does not cause axonal damage. Axonal integrity and normal behavior was also preserved when peroxisomes were deleted from astrocytes in GFAP-Pex5,/, mice. Nevertheless, peroxisomal metabolites were dysregulated in brain including a marked accumulation of VLCFA and a slight reduction in plasmalogens. Interestingly, despite minor targeting of oligodendrocytes in GFAP-Pex5,/, mice, these metabolic perturbations were also present in isolated myelin indicating that peroxisomal metabolites are shuttled between different brain cell types. We conclude that absence of peroxisomal metabolism in neurons and astrocytes does not provoke the neurodegenerative phenotype observed after deleting peroxisomes from oligodendrocytes. Lack of peroxisomal metabolism in astrocytes causes increased VLCFA levels in myelin, but this has no major impact on neurological functioning. © 2010 Wiley-Liss, Inc. [source] A Simple, One-Step Approach to Durable and Robust Superhydrophobic Textiles,ADVANCED FUNCTIONAL MATERIALS, Issue 22 2008Jan Zimmermann Abstract Superhydrophobic textile fabrics are prepared by a simple, one-step gas phase coating procedure by which a layer of polymethylsilsesquioxane nanofilaments is grown onto the individual textile fibers. A total of 11 textile fabrics made from natural and man made fibers are successfully coated and their superhydrophobic properties evaluated by the water shedding angle technique. A thorough investigation of the commercially relevant poly(ethylene terephthalate) fabric reveals an unparalleled long-term water resistance and stability of the superhydrophobic effect. Because of the special surface geometry generated by the nanoscopic, fibrous coating on the microscopic, fibrous textiles, the coated fabric remains completely dry even after two months of full immersion in water and stays superhydrophobic even after continuous rubbing with a skin simulating friction partner under significant load. Furthermore, important textile parameters such as tensile strength, color, and haptics are unaffected by the silicone nanofilament coating. For the first time, an in-depth characterization of the wetting properties, beyond simple contact angle measurements, as well as a thorough evaluation of the most important textile parameters is performed on a superhydrophobic fabric, which reveals a true potential for application. [source] Experimental haemophilic synovitis: rationale and development of a murine model of human factor VIII deficiencyHAEMOPHILIA, Issue 3 2004L. A. Valentino Summary., Haemophilia is a genetic disease as a result of the deficiency of blood coagulation factor VIII or IX. Bleeding is common, especially into joints where an inflammatory, proliferative synovitis develops resulting in a debilitating arthritis, haemophilic arthropathy. The pathogenesis of blood-induced haemophilic synovitis (HS) is poorly understood. The gross, microscopic and ultrastructural changes that occur in the synovial membrane following human and experimental hemarthrosis have been described. Repeated episodes of bleeding induce synoviocyte hypertrophy and hyperplasia, an intense neovascular response and inflammation of the synovial membrane. The component(s) in blood that initiates these changes is(are) not known, although iron is often proposed as one possibility. Here, we describe a novel murine model of human haemophilia A, which facilitates the examination of large number of animals and tissue specimens. The effects of hemarthrosis on the physical, gross and microscopic changes evoked following joint bleeding are described. Controlled, blunt trauma to the knee joint consistently resulted in joint swelling because of a combination of bleeding and inflammation. Hemosiderin was found in the synovial membrane. Similar to hemarthrosis in human haemophilia, joint bleeding resulted in acute morbidity evidenced by inactivity, weight loss and immobility. With time the animals recovered. The model of experimental murine HS described here has utility in the study of the pathogenesis of HS. This is the first of a series of articles, which will discuss the pathophysiology and characterize the model, with comparison of his model to others which have been published previously. It should provide a useful model to test potential therapeutic interventions. [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] Surprises in a ,Simple' System: 2,4-Diaminobenzenesulfonic AcidHELVETICA CHIMICA ACTA, Issue 9 2003Janice The search for the polymorphic forms of 2,4-diaminobenzenesulfonic acid (DBSA), known to exist since 1880, has revealed a surprisingly rich solid-state system for such a simple molecule. A monohydrate, a dimoiric hydrate, an anhydrate and two polymorphic forms of the hydrochloride of this material have thus far been prepared. Their characterization by microscopic and thermal methods, FT-IR spectroscopy, and single-crystal structure determination are described. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||