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Detailed Investigation (detailed + investigation)
Selected AbstractsDating the Gesta martyrum: a manuscript-based approachEARLY MEDIEVAL EUROPE, Issue 3 2000Clare Pilsworth The gesta martyrum are an anonymous and disparate group of texts celebrating saints venerated in early medieval Rome as having been martyred in that city. This paper investigates the problems involved in placing these texts in their early medieval contexts. Since the beginning of the twentieth century, when scholarship moved away from attempts to identify a core of authentic ancient tradition in these early medieval narratives, most work on the corpus has concentrated on dating the composition of the accounts of individual martyrs. Given the sparsity of absolute chronological markers through references or citations in other written sources, this has inevitably rested on circumstantial evidence and the reconstruction of probable contexts for the redaction of specific works. This paper argues that much new light can be shed on the development of the cult of Roman martyrs if we shift the focus of our investigation from the origin and composition of the Urtexts to the surviving manuscript witnesses , all bar one eighth century or later , and the complex process of transmission which they document. The earliest copies of gesta martyrum, in both legendaries and other manuscripts, reveal surprisingly diverse contexts of transmission. Detailed investigation of Vienna National bibliothek 357, which Dufourcq argued contains a copy of a collection of martyr-narratives available to Gregory the Great, shows that in fact this manuscript sheds light on interest in Roman martyrs north of the Alps in the late Carolingian period, and the networks of contact and communication through which information about the Roman martyrs was transmitted across time and space. [source] Topotactic Conversion Route to Mesoporous Quasi-Single-Crystalline Co3O4 Nanobelts with Optimizable Electrochemical PerformanceADVANCED FUNCTIONAL MATERIALS, Issue 4 2010Li Tian Abstract The growth of mesoporous quasi-single-crystalline Co3O4 nanobelts by topotactic chemical transformation from , -Co(OH)2 nanobelts is realized. During the topotactic transformation process, the primary , -Co(OH)2 nanobelt frameworks can be preserved. The phases, crystal structures, morphologies, and growth behavior of both the precursory and resultant products are characterized by powder X-ray diffraction (XRD), electron microscopy,scanning electron (SEM) and transmission electron (TEM) microscopy, and selected area electron diffraction (SAED). Detailed investigation of the formation mechanism of the porous Co3O4 nanobelts indicates topotactic nucleation and oriented growth of textured spinel Co3O4 nanowalls (nanoparticles) inside the nanobelts. Co3O4 nanocrystals prefer [0001] epitaxial growth direction of hexagonal , -Co(OH)2 nanobelts due to the structural matching of [0001] , -Co(OH)2//[111] Co3O4. The surface-areas and pore sizes of the spinel Co3O4 products can be tuned through heat treatment of , -Co(OH)2 precursors at different temperatures. The galvanostatic cycling measurement of the Co3O4 products indicates that their charge,discharge performance can be optimized. In the voltage range of 0.0,3.0,V versus Li+/Li at 40,mA g,1, reversible capacities of a sample consisting of mesoporous quasi-single-crystalline Co3O4 nanobelts can reach up to 1400,mA h g,1, much larger than the theoretical capacity of bulk Co3O4 (892,mA h g,1). [source] Comparison of DNA Complex Formation Behaviour for Two Closely Related Lexitropsin AnaloguesHELVETICA CHIMICA ACTA, Issue 5 2009Abstract Two closely related lexitropsin analogues that differ only in the form of the ,headgroup' functionality (CHO (for 1) vs. Ac (for 2)) have been studied in their DNA-binding capacity for the sequence d(GCATATATGC) using 1H-NMR spectroscopy. DNA-Complex formation for the CHO derivative was apparent from the observation of new NMR signals on titration of DNA with ligand. Detailed investigation and assignment of the data for a ligand/DNA-duplex ratio of 2,:,1 clearly delineated the structure as one associated with the ,minor groove' class of DNA complexes. The structure of the complex was determined on the basis of the acquired NMR data. Features characteristic of typical 2,:,1 minor-groove complexes were apparent. In a similar experimental approach, the Ac analogue ligand,DNA binding response was investigated. Despite the close similarity in chemical structure to the CHO case, the Ac analogue was found to produce NMR data of a much poorer quality. This was attributed to more rapid on/off chemical exchange equilibrium between ligand and DNA. From close analysis and comparison of the NMR data for the ,Ac' and ,CHO' headgroup ligand,DNA complexes, it was possible to ascertain that the same type of complex formed in each case but with different relative binding constants. Consideration of the nature and form of these complexes has been made with reference to a previously determined structure from our laboratory for the related lexitropsin analogue thiazotropsin A. [source] Eating between the Lines: Mississippian Migration and Stable Carbon Isotope Variation in Fort Ancient PopulationsAMERICAN ANTHROPOLOGIST, Issue 3 2009Robert A. Cook ABSTRACT Appreciating variation along the edges of traditional archaeological Culture Historical boundaries requires close consideration of social contexts associated with culture contact. We focus on dietary variation as a function of these concerns through a case study of Fort Ancient populations who, on average, consumed lower quantities of maize than their Mississippian neighbors as determined by stable carbon isotope ratios of bone collagen. However, this dichotomy is not as rigid as initially thought, with some Fort Ancient burials producing stable carbon isotope ratios similar to Mississippian cases. Detailed investigation of internal variation of carbon isotopes for human burials at the SunWatch site provides evidence that contact included small-scale Mississippian migrations to Fort Ancient sites. The main conclusion is that variation in diet and archaeological context can be a useful approach for examining prehistoric migration. [source] Two crystal modifications of (Pro-Pro-Gly)4 -Hyp-Hyp-Gly-(Pro-Pro-Gly)4 reveal the puckering preference of Hyp(X) in the Hyp(X):Hyp(Y) and Hyp(X):Pro(Y) stacking pairs in collagen helicesACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2010Kenji Okuyama Two crystal modifications of a collagen model peptide, (Pro-Pro-Gly)4 -Hyp-Hyp-Gly-(Pro-Pro-Gly)4 [where Hyp is (4R,2S)- l -hydroxyproline], showed very similar unit-cell parameters and belonged to the same space group P21. Both crystals exhibited pseudo-merohedral twinning. The main difference was in their molecular-packing arrangements. One modification showed pseudo-hexagonal packing, while the other showed pseudo-tetragonal packing. Despite their different packing arrangements, no significant differences were observed in the hydration states of these modifications. The peptide in the pseudo-tetragonal crystal showed a cyclic fluctuation of helical twists with a period of 20,Å, while that in the pseudo-hexagonal crystal did not. In these modifications, the puckering conformations of four of the 12 Hyp residues at the X position of the Hyp(X)-Hyp(Y)-Gly sequence were in the opposite conformations to the previous hypothesis that Hyp(X) residues involved in Hyp(X):Hyp(Y) and Hyp(X):Pro(Y) stacking pairs prefer up-puckering and down-puckering conformations, respectively. Detailed investigation of the molecular interactions between Hyp(X) and adjacent molecules revealed that these opposite conformations appeared because the puckering conformation, which follows the hypothesis, is subject to steric hindrance from the adjacent molecule. [source] Isomerism of the right atrial appendages: Clinical, anatomical, and microscopic study of a long-surviving case with asplenia and ciliary abnormalitiesCLINICAL ANATOMY, Issue 3 2003R. Raman Abstract This study describes a case of isomerism of the right atrial appendages (bilateral morphologically right atrial appendages associated with complex congenital cardiac lesions) with ciliary abnormalities. Detailed investigation included gross anatomic dissection, review of the clinical history, and light, confocal, and electron microscopy. Clinically, this 40-year-old, long-surviving male patient had relatively good health until 4 years before death, which was due to cardiac failure. Surgical intervention consisted only of a Blalock-Taussig shunt (anastomosis of the right subclavian artery to the right pulmonary artery) at 6 years of age. Despite the presence of complex cardiac malformations and asplenia, his longevity may be attributed to the connection of the pulmonary veins to the atrium without pulmonary venous obstruction, pulmonary valvar stenosis rather than atresia, no significant atrioventricular valve regurgitation, and no serious infections during his life. Microscopic examination of bronchial epithelium revealed a narrow, disorganized epithelium with abundant goblet cells and short, angulated cilia with a random orientation and possibly an abnormal central microtubule doublet. These abnormalities were not present in controls, and have been noted in primary ciliary dyskinesia (PCD) or Kartagener's syndrome. Because this syndrome has classically been thought to cause random lateralization resulting in a mirror-imaged arrangement of the organs, the occurrence of truly isomeric patterns is not widely recognized. Whereas polysplenia and left bronchial isomerism have been reported to occur in immotile cilia syndrome, this is the first report to present detailed postmortem anatomic evidence of isomerism of the right atrial appendages, right bronchial isomerism, and asplenia in association with microscopy suggesting ciliary abnormalities. Clin. Anat. 16:269,276, 2003. © 2003 Wiley-Liss, Inc. [source] Oncogenes in thyroid cancerCLINICAL OTOLARYNGOLOGY, Issue 5 2003D.S. Kim There have been significant advances in our understanding of carcinogenesis at the molecular level over the last 25 years. Oncogenes are of major interest as part of our search for knowledge surrounding the aetiology of cancer. There are several oncogenes associated with thyroid cancer. Detailed investigation of the nature and function of these tumour genes has provided important insights into both the tumour biology and the complex biochemical pathways of normal cellular functioning. Our knowledge of oncogene biology offers the hope of better diagnostic, therapeutic and prognostic modalities in our fight against this and other common cancers. Development of specific thyroid tumour markers and gene therapy is now a realistic prospect to supplement our present armamentarium of surgery and radiotherapy. This review aims to outline the pertinent information gained so far from studies of these oncogenes and provides both clinical relevance and fuel for further interest amongst the ENT thyroid community in this exciting area of research. [source] EFFECT OF OSMOTIC TREATMENT WITH CONCENTRATED SUGAR AND SALT SOLUTIONS ON KINETICS AND COLOR IN VACUUM CONTACT DRYINGJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 6 2007S.M.A. RAHMAN ABSTRACT An experimental study of osmotic dehydration (OD) of selected heat-sensitive products was carried out in a laboratory-scale vacuum contact dryer. Cubes of potato and apple were examined as model heat-sensitive objects. Experiments were conducted at different conduction heat input levels with wall temperatures in the range 35,45C under vacuum and also in pure vacuum without any external heat input. Detailed investigations were carried out of OD on drying performance, product temperature and color of the dried product. PRACTICAL APPLICATIONS Osmotic treatment of potato and apple samples using concentrated sugar solution shows better osmotic dehydration as well as drying rate in a vacuum contact drying system. This information may help to select the osmotic agent in any industrial application for faster drying rate in vacuum contact drying specially for food products. Moreover this work shows the analysis to find out the starting point of precipitation of osmotic agent inside the products in terms of drying time, temperature and moisture content. This information will be helpful for critical analysis in osmotic dehydration technique which in turns may help for optimum design. [source] Incidence, spectrum and antibiotic sensitivity pattern of bacterial infections among patients with acute pancreatitisJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 9 2001Pramod Kumar Garg Abstract Background and Aim: Secondary infection of pancreatic necrotic tissue and peripancreatic fluid is a serious complication of acute pancreatitis resulting in significant morbidity and mortality. The aim of this study was to find out the spectrum of bacterial infections, and their antibiotic sensitivity pattern in patients with acute pancreatitis. Methods: All consecutive patients with acute pancreatitis were studied prospectively. Detailed investigations were carried out to identify bacterial infections and their antibiotic sensitivities in patients with suspected infection. These investigations included cultures of various body fluids, throat swabs, indwelling cannula and catheter tips. Pancreatic tissue was obtained by using needle aspiration or at surgery for Gram's stain, culture and sensitivity. All cultures were repeated until the presence of infection was confirmed or excluded. Results: A total of 169 patients with acute pancreatitis were studied during the period between January 1997 and June 2000 (mean age 41.3 years; 116 males and 53 females). Of the 169 patients, 63 had infections at various sites. A total of 80 cultures were positive, and 12 different bacterial isolates were cultured from samples taken from these 63 patients. Polymicrobial infection was seen in 32% of patients. Twenty-four patients had a confirmed pancreatic infection. Blood cultures had a growth of organisms in 19 patients, with evidence of ongoing or worsening pancreatitis, thus raising a strong suspicion of infected necrosis in them. The commonest organisms were Escherichia coli from 20 cultures and Pseudomonas aeruginosa from 18 cultures. The antibiotic sensitivity pattern showed that most bacteria were sensitive to third generation cephalosporins and quinolones; notably among them were cefotaxime, ceftazidime, and ciprofloxacin. Conclusion: Bacterial infections were seen in 37% of patients with acute pancreatitis. The commonest organisms were Pseudomonas aeruginosa and Escherichia coli. Most bacterial isolates were sensitive to third generation cephalosporins and quinolones. [source] Biotic diachroneity during the Ordovician Radiation: evidence from South ChinaLETHAIA, Issue 3 2006Renbin Zhan The Ordovician radiation was one of the most marked and sustained increases in Phanerozoic biodiversification; nevertheless it occurred against a background of minimal global climatic and environmental perturbations. Detailed investigations of the Ordovician successions on the Yangtze Platform of the South China palaeoplate indicate that: (1) the brachiopod ,- and ,-diversity changes are diachronous; (2) macroevolutionary patterns were different across the South China palaeoplate, with the Early Ordovician brachiopod radiation first occurring in normal marine, shallow-water environments and then moving gradually to both nearer-shore and offshore locations; (3) the main contributors to the initial Ordovician brachiopod radiation were the Orthida and Pentamerida; the typical Ordovician brachiopod fauna, dominated by the Orthida and Strophomenida, did not appear until the late Mid Ordovician (Undulograptus austrodentatus Biozone) when the Strophomenida apparently replaced the dominant position of the Pentamerida within the fauna; (4) different ecotypes (e.g., sessile benthos, mobile benthos together with pelagic and planktonic organisms) demonstrate substantially different macroevolutionary patterns. The Ordovician brachiopod radiation of South China was apparently earlier than that suggested by global trends together with the data available from other palaeoplates or terranes, which may be related to its unique palaeogeographic position (peri-Gondwanan terrane gradually moving to equatorial latitudes). [source] Specific response of ultra-thin metal oxide films to gasPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2009etkus Abstract Tin and indium oxide ultra-thin film (UTF) based structures are investigated in the present study. Current-voltage characteristics (IVC) are measured in the samples by a contact current mode of scanning probe microscopy (SPM). It is proved that the IVC splits into two paths corresponding to increase and decrease of applied voltage, respectively. Detailed investigations of the electrical properties of the ultra-thin metal oxide (MOX) films revealed a dependence of the IVC on the structure of the films, on initial conductivity and on the surrounding gases. It was proved that the IVC is typically split only if the maximum dc-voltage exceeds some critical magnitude that is not the same in indium and tin oxide based films. The properties of the ultra-thin MOX structures are explained in terms of distribution of stoichiometry in MOX based nanometer systems. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Control synthesis of iron oxide nanospheres using solution chemistryPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2007M. Z. Wu Abstract A facile solution chemistry approach to the batch synthesis of magnetite nanocrystals is developed. By using different starting materials, the control of particle size and size distribution can be achieved. Detailed investigations into the morphology and size distribution of the final products were carried out with the aid of field emission scanning electronic microscopy (FESEM). The crystal structure was studied by powder X ray diffraction (XRD). Vibrating sample magnetometer (VSM) was used to study the magnetic properties of these sphere-like products. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Experimental and Numerical Investigations for Cyclic Thermal ShocksPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2005Franz-Barthold Gockel Thermal shock is an extreme form of thermo-mechanical loading. Detailed investigations of thermal shock and live time analysis close to reality are necessary in industrial engineering in order to get a good prediction of life expectancy of high quality and safety relevant machine components. The first part of this paper concentrates on experimental investigations of macroscopic quantities like temperature, deformation, damage and crack propagation. Additionally first results on parameter studies for finite element thermal shock simulations on the thermal-mechanical problem are summarized. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The combination of the antitumoural pyridyl cyanoguanidine CHS 828 and etoposide in vitro,from cytotoxic synergy to complete inhibition of apoptosisBRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2002P Martinsson The present study was aimed at elucidating the apoptosis inhibitory properties of the cyanoguanidine CHS 828. CHS 828 exhibits impressive cytotoxic activity in vitro and in vivo. Apoptosis is not its main mode of cytotoxic effect, and we have previously proposed a dual mechanism, where CHS 828 inhibits its own cell death pathways. Etoposide on the other hand, is a well-established anticancer agent with documented effect in a number of malignancies, induces apoptosis through extensively studied caspase dependent pathways. Here we studied the combined effect of the two drugs in the human lymphoma cell line U-937 GTB. Cytotoxicity was evaluated as total viability measured by the fluorometric microculture cytotoxicity assay (FMCA). Caspase activity was assessed by colorimetric detection of specific cleavage products for caspases 3, 8 and 9, respectively. Morphology was evaluated in May-Grünwald/Giemsa stained preparations. Interaction analysis based on FMCA results of simple combination exposure revealed impressive synergistic effect on cell kill. Detailed investigations of the kinetics involved showed that short pre-exposure (0,12 h) to CHS 828 enhanced caspase activation by etoposide, while longer pre-exposure (18,48 h) inhibited both caspase activation and apoptotic morphology otherwise induced by etoposide. The present results support the theory that CHS 828 block specific cell death pathways. The synergistic results are promising for future combination trials in animals, however, different dosing schedules should be considered, in order to investigate whether the above findings translate into the in vivo setting. British Journal of Pharmacology (2002) 137, 568,573. doi:10.1038/sj.bjp.0704888 [source] Inhibition of slow Ca2+ -activated K+ current by 4-aminopyridine in rat hippocampal CA1 pyramidal neuronesBRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2002Mogens Andreasen The effect of 4-aminopyridine (4-AP) on the slow afterhyperpolarization (sAHP) seen after high frequency dendritic or somatic firing was investigated in rat hippocampal CA1 pyramidal neurones (PC). Intracellular recordings were obtained from the distal apical dendrites and somata and suprathreshold depolarizing current pulses were used to evoke a sAHP. The sAHP was blocked by low concentrations of carbacholine (Cch) but insensitive to high concentrations of apamin. In the presence of extracellular 4-AP, the first dendritic sAHP evoked was reduced compared to a maximal sAHP evoked in the absence of 4-AP. The reduction was evident at submillimolar concentration and increased to about 80% with 4 mM 4-AP. The stability of the 4-AP-induced block was affected by the type of anion used in the electrode solution. With K+ acetate (KAc) or K+ methylsulphate (KMeSO4) containing electrodes, the block was progressively removed during the initial 300 , 400 s of recordings. With KCl containing electrodes, the block remained stable and was 10% larger than that obtained with acetate. Detailed investigations showed that intracellular acetate promotes the removal of the 4-AP-induced block in an activity-dependent manner. Intracellularly applied 4-AP also induced an acetate-sensitive block of the dendritic sAHP. 4-AP also blocked the somatic sAHP and the stability of the block showed the same sensitivity towards anions as the dendritic sAHP. Thus 4-AP appears to block the slow Ca2+ -activated K+ current underlying the sAHP in a complex manner which is sensitive to certain types of anions. British Journal of Pharmacology (2002) 135, 1013,1025; doi:10.1038/sj.bjp.0704533 [source] Precautionary Savings Behavior of Maritally Stressed CouplesFAMILY & CONSUMER SCIENCES RESEARCH JOURNAL, Issue 3 2006Michael S. Finke According to precautionary savings theory, households tend to save more when future income is less certain. Divorce often results in reduced levels of household income and individual consumption comparable to other potential income shocks. Households that will divorce or separate in 5 years are identified from the Panel Study of Income Dynamics (1994,1999) to determine whether these households maintain greater wealth holdings in anticipation of divorce. When spouses earn comparable incomes, divorce-prone households have significantly higher wealth levels (p < .01) than households that remain married. When there is a higher-earning spouse, households have significantly lower wealth levels (p < .01) than households that remain married. Results suggest that spouses with comparable earnings treat divorce as a wealth shock, whereas higher-earning spouses rationally dissave when divorce is imminent. Equitable wealth allocation for lower-earning spouses may require a more detailed investigation of predivorce wealth changes. [source] Single amino acid repeats in signal peptidesFEBS JOURNAL, Issue 15 2010abaj There has been an increasing interest in single amino acid repeats ever since it was shown that these are the cause of a variety of diseases. Although a systematic study of single amino acid repeats is challenging, they have subsequently been implicated in a number of functional roles. In general surveys, leucine runs were among the most frequent. In the present study, we present a detailed investigation of repeats in signal peptides of secreted and type I membrane proteins in comparison with their mature parts. We focus on eukaryotic species because single amino acid repeats are generally rather rare in archaea and bacteria. Our analysis of over 100 species shows that repeats of leucine (but not of other hydrophobic amino acids) are over-represented in signal peptides. This trend is most pronounced in higher eukaryotes, particularly in mammals. In the human proteome, although less than one-fifth of all proteins have a signal peptide, approximately two-thirds of all leucine repeats are located in these transient regions. Signal peptides are cleaved early from the growing polypeptide chain and then degraded rapidly. This may explain why leucine repeats, which can be toxic, are tolerated at such high frequencies. The substantial fraction of proteins affected by the strong enrichment of repeats in these transient segments highlights the bias that they can introduce for systematic analyses of protein sequences. In contrast to a general lack of conservation of single amino acid repeats, leucine repeats were found to be more conserved than the remaining signal peptide regions, indicating that they may have an as yet unknown functional role. [source] Mapping of nasopharyngeal carcinoma tumor-suppressive activity to a 1.8-megabase region of chromosome band 11q13GENES, CHROMOSOMES AND CANCER, Issue 1 2002Yue Cheng Nasopharyngeal carcinoma (NPC) is a malignancy that is particularly prevalent among populations from Southern China and Southeast Asian countries. Evidence for a genetic contribution to the disease has been documented, although the genetic basis for NPC development is not yet fully understood. Previous functional evidence of tumor-suppressive activity on chromosome band 11q13 in NPC was obtained using a microcell-mediated chromosome-transfer approach with HONE1 NPC cells. In the present study, this region was subjected to a detailed investigation of microcell hybrids and their tumor segregants using microsatellite analysis to narrow down the region of tumor-suppressive activity. Fluorescence in situ hybridization was also performed with BAC and cosmid probes to confirm the microsatellite data. The critical region responsible for tumor suppression was narrowed down to a 1.8-Mb interval, which does not tolerate an additional normal allele by chromosome transfer. One or two alleles from either endogenous or exogenous chromosomes at 11q13 were consistently eliminated during tumor growth. Results of this study suggest that a candidate tumor-suppressor gene, not the MEN1 gene, maps between D11S4907 and GSTP1 in NPC. © 2002 Wiley-Liss, Inc. [source] The Influence of the Parameter "Temperature" on the Abrasiveness of RockGEOMECHANICS AND TUNNELLING, Issue 1 2008Stefan Eberl cand.rer.mont. The article deals with the influence of temperature produced in the cutting process on rock abrasiveness and tool wear. Basically it was to clarify which effects take place when quartz or rock with significant quartz content is heated up to a certain temperature. Does the quartz jump from low into high quartz happening at 573 °C cause an increase in abrasiveness of mineral and rock or not? To find out, a certain number of Cerchar abrasiveness index tests were done for a detailed investigation of this topic. Additionally, to get a better understanding what really happens inside rock structure additionally other rock parameters like unconfined compressive strength, Brazilian tensile strength, ultrasonic wave velocity and density were determined on untreated and heated and subsequently cooled down rock samples. The final output of the research work showed that rocks show a very specific and significant reaction to thermal stresses induced into their structure resulting in a different behaviour regarding abrasiveness and fracturing. Einfluss des Parameters "Temperatur" auf die Abrasivität von Fels Der Artikel beschäftigt sich mit dem Einfluss der während des Schneidprozesses entstehenden Temperatur auf die Abrasivität von Gestein und auf den Verschleiß des Schneidwerkzeugs. Es sollte geklärt werden, welche Effekte auftreten, wenn Quarz und Gestein mit erheblichem Quarzgehalt bis zu einer bestimmten Temperatur erhitzt werden. Erzeugt der Quarzsprung, der bei 573 °C stattfindet, von Tiefquarz zu Hochquarz einen Anstieg in der Abrasivität von Mineralen und Gesteinen oder nicht? Um dies herauszufinden, sind eine bestimmte Anzahl von Cerchar Abrasivitätstests durchgeführt worden. Um ein besseres Verständnis zu erhalten, was wirklich in der Struktur des Gesteins passiert, sind weitere Parameter wie einachsiale Druckfestigkeit, Spaltzugfestigkeit, Ultraschallwellengeschwindigkeit und Dichte an unbehandelten und aufgeheizten und wieder abgekühlten Gesteinsproben bestimmt worden. Die Forschungsarbeit hat gezeigt, dass Gesteine eine sehr spezifische und signifikante Reaktion auf thermische Beanspruchungen ihres Gefüges zeigen, was letztlich in einem verschiedenartigen Verhalten hinsichtlich Abrasivität und Bruchverhalten zum Ausdruck kommt. [source] Surfactant-Assisted Preparation of Novel Layered Silver Bromide-Based Inorganic/Organic Nanosheets by Pulsed Laser Ablation in Aqueous Media,ADVANCED FUNCTIONAL MATERIALS, Issue 17 2007C. He Abstract A novel layered AgBr-based inorganic/organic nanocomposite was prepared by pulsed laser ablation (PLA) of Ag in aqueous media in the presence of cetyltrimethylammonium bromide (CTAB), and the formation mechanism of two-dimensional nanosheet was discussed. TEM observations indicate that the obtained AgBr-based inorganic/organic nanocomposite possesses a well-defined two-dimensional shape and that the size of the nanosheet can be changed with the surfactant concentration in the solution. X-ray diffraction (XRD) pattern was composed of a series of peaks that could be indexed to (00l) reflections of a layered structure, and the basal spacing of 20.0,Å indicated that the surfactant was included between the AgBr interlayers in an interdigitated bilayer arrangement. In contrast, a layered inorganic/organic nanocomposite cannot be formed at a CTAB concentration lower than the critical micelle concentration (CMC). Based on our detailed investigation, we proposed the nanocomposite formation process, that is, that negatively charged inorganic AgBr was produced by a strong reaction between the ablated Ag species and the bromide ions, which are concurrently assembling with cationic surfactant molecules controlled by the charge-matching mechanism. [source] Hillslope-swamp interactions and flow pathways in a hypermaritime rainforest, British ColumbiaHYDROLOGICAL PROCESSES, Issue 15 2003D. F. Fitzgerald Abstract The process of water delivery to a headwater stream in a hypermaritime rainforest was examined using a variety of physical techniques and tracing with dissolved organic carbon (DOC) and the stable isotopes of water. Headwater swamps, often the major discharge zones for water draining off steep forest slopes, strongly affect the physical and chemical character of streamflow in the region. The headwater swamp selected for detailed investigation was sustained by relatively constant groundwater input from the steep colluvial slopes that maintained the water table above the ground surface. During significant storm events the water table rose quickly and the swamp expanded to engulf marginal pools that developed rapidly on the adjacent ground surfaces. The corresponding release of surface water directly to the stream typically comprised up to 95% of total stream discharge. The proportion of groundwater seepage to the stream by matrix flow (<1%) and via macropore-fed springs (up to 73%) increased during the recession period, but could not be sustained over the longer term. In more protracted drying periods, deep groundwater contributions to the stream were routed first to the headwater swamp. Dissolved organic carbon (DOC) in the stream, measured daily or more frequently during storm events, was found to be directly proportional to discharge, owing to the domination of DOC-rich headwater-swamp water sources. Although ,18O and ,2H composition of rainwater, groundwater and stream flow were found to be similar, deuterium excess (d ,2H , 8,18O) of water components was often found to be distinct, and suggested short water residence times of roughly 12 days for one event. Overall, observations of a typical headwater swamp reveal that the groundwater regime is dominated by rapid infiltration and short, emergent flow paths. With a relatively short turnover time, potential disturbances to the system by harvesting of upslope areas can be expected to occur rapidly. Forest managers can mitigate some of the harmful effects of logging operations by respecting the integrity of headwater wetland systems. The nature and magnitude of such perturbations will require further study. Copyright © 2003 John Wiley & Sons, Ltd. [source] Factors controlling the chemical evolution of travertine-depositing rivers of the Barkly karst, northern AustraliaHYDROLOGICAL PROCESSES, Issue 15 2002Russell N. Drysdale Abstract Groundwaters feeding travertine-depositing rivers of the northeastern segment of the Barkly karst (NW Queensland, Australia) are of comparable chemical composition, allowing a detailed investigation of how the rate of downstream chemical evolution varies from river to river. The discharge, pH, temperature, conductivity and major-ion concentrations of five rivers were determined by standard field and laboratory techniques. The results show that each river experiences similar patterns of downstream chemical evolution, with CO2 outgassing driving the waters to high levels of calcite supersaturation, which in turn leads to widespread calcium carbonate deposition. However, the rate at which the waters evolve, measured as the loss of CaCO3 per kilometre, varies from river to river, and depends primarily upon discharge at the time of sampling and stream gradient. For example, Louie Creek (Q = 0·11 m3 s,1) and Carl Creek (Q = 0·50 m3 s,1) have identical stream gradients, but the loss of CaCO3 per kilometre for Louie Creek is twice that of Carl Creek. The Gregory River (Q = 3·07 m3 s,1), O'Shanassy River (Q = 0·57 m3 s,1) and Lawn Hill Creek (Q = 0·72 m3 s,1) have very similar gradients, but the rate of hydrochemical evolution of the Gregory River is significantly less than either of the other two systems. The results have major implications for travertine deposition: the stream reach required for waters to evolve to critical levels of calcite supersaturation will, all others things being equal, increase with increasing discharge, and the length of reach over which travertine is deposited will also increase with increasing discharge. This implies that fossil travertine deposits preserved well downstream of modern deposition limits are likely to have been formed under higher discharge regimes. Copyright © 2002 John Wiley & Sons, Ltd. [source] Maternal embryonic leucine zipper kinase transcript abundance correlates with malignancy grade in human astrocytomasINTERNATIONAL JOURNAL OF CANCER, Issue 4 2008Suely K.N. Marie Abstract We have performed cDNA microarray analyses to identify gene expression differences between highly invasive glioblastoma multiforme (GBM) and typically benign pilocytic astrocytomas (PA). Despite the significant clinical and pathological differences between the 2 tumor types, only 63 genes were found to exhibit 2-fold or greater overexpression in GBM as compared to PA. Forty percent of these genes are related to the regulation of the cell cycle and mitosis. QT-PCR validation of 6 overexpressed genes: MELK, AUKB, ASPM, PRC1, IL13RA2 and KIAA0101 confirmed at least a 5-fold increase in the average expression levels in GBM. Maternal embryonic leucine zipper kinase (MELK) exhibited the most statistically significant difference. A more detailed investigation of MELK expression was undertaken to study its oncogenic relevance. In the examination of more than 100 tumors of the central nervous system, we found progressively higher expression of MELK with astrocytoma grade and a noteworthy uniformity of high level expression in GBM. Similar level of overexpression was also observed in medulloblastoma. We found neither gene promoter hypomethylation nor amplification to be a factor in MELK expression, but were able to demonstrate that MELK knockdown in malignant astrocytoma cell lines caused a reduction in proliferation and anchorage-independent growth in in vitro assays. Our results indicate that GBM and PA differ by the expression of surprisingly few genes. Among them, MELK correlated with malignancy grade in astrocytomas and represents a therapeutic target for the management of the most frequent brain tumors in adult and children. © 2007 Wiley-Liss, Inc. [source] A novel photochromic time,temperature indicator to support cold chain managementINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2010Judith Kreyenschmidt Summary A detailed investigation of the behaviour of a new printable photochromic time,temperature indicator (TTI) was conducted to characterise its properties under specific temperature conditions and to analyse the influence of ultra violet (UV) light irradiation (activation) on the discolouration process. The reproducibility of the charging process and the discolouration process of the TTI were analysed. For different charging times the calculated activation energies based on the Arrhenius model ranged from 23.2 to 25.3 kcal mol,1 depending on the UV light irradiation (charging time). A quality contour diagram was established to define the appropriate charging time for different kinds of products. Due to the possibility of defining the shelf life of a TTI by different charging times, this novel TTI constitutes a reliable tool to monitor the cold chains of a broad range of food products on their way from production to consumption. [source] Long-term changes in distribution and chemistry of middle Miocene to Quaternary volcanism in the Chokai-Kurikoma area across the Northeast Japan ArcISLAND ARC, Issue 1 2004Hirofumi Kondo Abstract To understand the characteristics of long-term spatial and temporal variation in volcanism within a volcanic arc undergoing constant subduction since the cessation of back-arc opening, a detailed investigation of middle Miocene to Quaternary volcanism was carried out within the Chokai-Kurikoma area of the Northeast Japan Arc. This study involved a survey of available literature, with new K,Ar and fission track dating, and chemical analyses. Since 14 Ma, volcanism has occurred within the Chokai-Kurikoma area in specific areas with a ,branch-like' pattern, showing an east,west trend. This is in marked contrast to the widespread distribution of volcanism with a north,south trend in the 20,14 Ma period. The east,west- trending ,branches' are characterized by regular intervals (50,100 km) of magmatism along the arc. These branches since 14 Ma are remarkably discrepant to the general northwest,southeast or north-northeast,south-southwest direction of the crustal structures that have controlled Neogene to Quaternary tectonic movements in northeast Japan. In addition, evidence indicating clustering and focusing of volcanism into smaller regions since 14 Ma was verified. Comparison of the distribution and chemistry of volcanic rocks for three principal volcanic stages (11,8, 6,3 and 2,0 Ma) revealed that widely but sparsely distributed volcanic rocks had almost the same level of alkali and incompatible element concentrations throughout the area (with the exception of Zr) in the 11,8 Ma stage. However, through the 6,3 Ma stage to the 2,0 Ma stage, the concentration level in the back-arc cluster increased, while that in the volcanic front cluster remained almost constant. Therefore, the degree of partial melting has decreased, most likely with a simultaneous increase in the depth of magma segregation within the back-arc zone, whereas within the volcanic front zone, the conditions of magma generation have changed little over the three stages. In conclusion, the evolution of the thermal structure within the mantle wedge across the arc since 14 Ma has reduced the extent of ascending mantle diapirs into smaller fields. This has resulted in the tendency for the distribution of volcanism to become localized and concentrated into more specific areas in the form of clusters from the late Miocene to Quaternary. [source] On Doing Being a Stranger: The Practical Constitution of Civil InattentionJOURNAL FOR THE THEORY OF SOCIAL BEHAVIOUR, Issue 1 2005STEFAN HIRSCHAUER ABSTRACT:The article takes on a less developed aspect of the sociology of the stranger: the normalized non-relations people in urban settings establish in their effort to stay strangers for one another. How is their "civil inattention"accomplished in practice? What is the social orderliness of "asocial" relations? In order to answer these questions the article uses the elevator as a sociological research instrument allowing for a highly detailed investigation in structural problems of public encounters: bodily navigation, contact avoidance, feigned preoccupation, and the blocking of the automatism by which co-present bodies start interactions. The setting used for the investigation also raises questions about how the artifact and the bodies present are integrated into the interaction order. The "heteromobile" of the elevator offers specific sociotechnical scripts for interaction. While the human actors work hard at doing nothing, their bodies seem to take over their agency. The specific challenge of elevator riding for the enactment of indifference is the vanishing of actors: undoing presence. [source] Supercritical water oxidation of quinoline in a continuous plug flow reactor,part 2: kineticsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2006Lisete DS Pinto Abstract The results of a detailed investigation into the kinetics of quinoline oxidation in supercritical water are presented. The novel kinetic data presented were obtained in a continuously operated, plug flow reactor where parameters such as temperature, pressure, residence time and stoichiometric ratio of oxidant to quinoline were investigated and detailed in the companion paper (Pinto LDS, Freitas dos Santos LMF, Al-Duri B and Santos RCD, Supercritical water oxidation of quinoline in a continuous plug flow reactor,part 1: effect of key operating parameters. J Chem Technol Biotechnol). An induction time was experimentally observed, ranging from 1.5 to 3.5 s, with longer times observed in experiments carried out at lower temperatures. A pseudo-first-order rate expression with respect to quinoline concentration (with oxygen excess) was first adopted and the activation energy of 234 kJ mol,1 and a pre-exponential factor of 2.1 × 1014 s,1 were estimated. Furthermore, an integral power rate model expression was established, attributing a reaction order for quinoline as 1 and for oxygen as 0.36. An activation energy and pre-exponential factor for this model were determined as 224 kJ mol,1 and 3.68 × 1014 M,0.36 s,1, respectively. A global rate expression was then regressed for the quinoline reaction rate from the complete set of data. The resulting activation energy was 226 ± 19 kJ mol,1 and the pre-exponential factor was 2.7 × 1013 ± 2 M,0.1 s,1. The reaction orders for quinoline and oxygen were 0.8 ± 0.1 and 0.3 ± 0.1, respectively. It was shown that the least-squares regression method provided the best-fit model for experimental results investigated in this study. Copyright © 2006 Society of Chemical Industry [source] Spin states in polynuclear clusters: The [Fe2O2] core of the methane monooxygenase active siteJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 12 2006Carmen Herrmann Abstract The ability to provide a correct description of different spin states of mono- and polynuclear transition metal complexes is essential for a detailed investigation of reactions that are catalyzed by such complexes. We study the energetics of different total and local spin states of a dinuclear oxygen-bridged iron(IV) model for the intermediate Q of the hydroxylase component of methane monooxygenase by means of spin-unrestricted Kohn,Sham density functional theory. Because it is known that the spin state total energies depend systematically on the density functional, and that this dependence is intimately connected to the exact exchange admixture of present-day hybdrid functionals, we compare total energies, local and total spin values, and Heisenberg coupling constants calculated with the established functionals BP86 and B3LYP as well as with a modified B3LYP version with an exact exchange admixture ranging from 0 to 24%. It is found that exact exchange enhances local spin polarization. As the exact exchange admixture increases, the high-spin state is energetically favored, although the Broken-Symmetry state always is the ground state. Instead of the strict linear variation of the energy splittings observed for mononuclear complexes, a slightly nonlinear dependence is found. The Heisenberg coupling constants JFe1Fe2,evaluated according to three different proposals from the literature,are found to vary from ,129 to ,494cm,1 accordingly. The experimental finding that intermediate Q has an antiferromagnetic ground state is thus confirmed. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1223,1239, 2006 [source] How academics use technology in teaching and learning: understanding the relationship between beliefs and practiceJOURNAL OF COMPUTER ASSISTED LEARNING, Issue 2 2006J. D. Bain Abstract This paper reports on a detailed investigation into the beliefs and practices of teachers in 22 computer-assisted learning projects in Australia in the mid-1990s. Detailed interview data were obtained, supported by the project software and other curriculum materials. The interview transcripts and documentary material were collated and condensed into rich descriptions; these were then coded on a number of belief and practice dimensions. The resulting profiles were clustered into five belief,practice categories: thoughtful instructors, pre-emptive professionals, conversational constructivists, learning facilitators and situated knowledge negotiators. These complex, yet interpretable, patterns of relationships between beliefs and practices are useful in understanding teachers' reluctance to change their teaching, one instance of which is the relatively limited uptake of technology in higher education. [source] Dissociation mechanisms and implication for the presence of multiple conformations for peptide ions with arginine at the C-terminus: time-resolved photodissociation studyJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 7 2010So Hee Yoon Abstract Time-resolved photodissociation (PD) patterns of singly protonated peptides with arginine at the C-terminus (C-arg peptide ions) have been used to classify the dissociation channels into two categories, i.e. high-energy channels generating v, w and x and low-energy ones generating b, y and z. x + 1 formed by C,CO cleavage seems to be the intermediate ion in high-energy channels just as a + 1 is for N-arg peptide ions. Difference in time-resolved pattern indicates that the two sets of channels, high- and low-energy ones, are not in direct competition. Noncompetitive dissociation is also indicated by the observation of anomalous effect of matrix used in matrix-assisted laser desorption ionization, a cooler matrix generating more high-energy product ions both in spontaneous dissociation and in PD. Results from detailed investigation suggest that the two sets of channels start from two (or more) different conformations. Copyright © 2010 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||