63,813 research outputs found
Synthesis of spherical nanoparticles of Cu2L2O5 (L = Ho, Er) from W/O microemulsions
No full textNanoparticles of Cu2L2O, (L = Ho, Er) (15-25 nm in size) were synthesised by the intermediate use of W/O microemulsions. In this process the aqueous cores of water/cetyltrimethylammonium bromide/n-octane/1-butanol microemulsions were used as microreactors for the precipitation of Cu2Ho2(CO3)(4)(OH)(2) (25-30 nm) and Cu2Er2(CO3)(4)(OH)(2) (10-40 nm) as precursors. These mixed salts were separated and further decomposed to the corresponding mixed oxides at 900 degrees C for 16 h. All solids were characterised by scanning and transmission electron microscopy, IR, XRPD, ICP-OES, TCA, XPS measurements and elemental analyses
The 1961 Kampong Bukit Ho Swee fire and the making of modern Singapore
Full text linkBy 1970, Singapore’s urban landscape was dominated by high-rise blocks of planned public housing built by the People’s Action Party government, signifying the establishment of a high modernist nation-state. A decade earlier, the margins of the City had been dominated by kampongs, home to semi-autonomous communities of low-income Chinese families which freely built, and rebuilt, unauthorised wooden houses. This change was not merely one of housing but belied a more fundamental realignment of state-society relations in the 1960s. Relocated in Housing and Development Board flats, urban kampong families were progressively integrated into the social fabric of the emergent nation-state. This study examines the pivotal role of an event, the great Kampong Bukit Ho Swee fire of 1961, in bringing about this transformation. The redevelopment of the fire site in the aftermath of the calamity brought to completion the British colonial regime’s ‘emergency’ programmes of resettling urban kampong dwellers in planned accommodation, in particular, of building emergency public housing on the sites of major fires in the 1950s. The PAP’s far greater political resolve, and the timing of and state of emergency occasioned by the scale of the 1961 disaster, enabled the government to rehouse the Bukit Ho Swee fire victims in emergency housing in record time. This in turn provided the HDB with a strategic platform for clearing other kampongs and for transforming their residents into model citizens of the nation-state. The 1961 fire’s symbolic usefulness extended into the 1980s and beyond, in sanctioning the PAP’s new housing redevelopment schemes. The official account of the inferno has also become politically useful for the government of today for disciplining a new generation of Singaporeans against taking the nation’s progress for granted. Against these exalted claims of the fire’s role in the Singapore Story, this study also examines the degree of actual change and continuity in the social and economic lives of the people of Bukit Ho Swee after the inferno. In some crucial ways, the residents continued to occupy a marginal place in society while pondering, too, over the unresolved question of the cause of the fire. These continuities of everyday life reflect the ambivalence with which the citizenry regarded the high modernist state in contemporary Singapore
Improved sub-threshold Slope in RF vertical MOSFETS using a frame gate architecture
Full text linkWe report a CMOS-compatible vertical MOSFET, which incorporates a frame gate architecture suitable for application in RF circuits. Fabricated surround gate vertical MOSFETs with the frame gate architecture show no degradation of short channel effects when the channel length is scaled, while control devices show significantly degraded sub-threshold slope and DIBL. The frame gate vertical MOSFETs show near ideal sub-threshold slopes of 70-80mV/decade and DIBL of 30-35mV/V in a 100 nm gate length nMOS device. In contrast, the control vertical MOSFETs without the frame gate exhibit sub-threshold slopes of 110 to 140 mV/decade and DIBL of 100 to 280 mV/V. This improved sub-threshold slope is explained by the elimination of etch damage during gate etch
Cooling rates of neutron stars and the young neutron star in the Cassiopeia A supernova remnant
No full textWe explore the thermal state of the neutron star in the Cassiopeia A supernova remnant using the recent result of Ho & Heinke that the thermal radiation of this star is well described by a carbon atmosphere model and the emission comes from the entire stellar surface. Starting from neutron star cooling theory, we formulate a robust method to extract neutrino cooling rates of thermally relaxed stars at the neutrino cooling stage from observations of thermal surface radiation. We show how to compare these rates with the rates of standard candles – stars with non-superfluid nucleon cores cooling slowly via the modified Urca process. We find that the internal temperature of standard candles is a well-defined function of the stellar compactness parameter x=rg/R, irrespective of the equation of state of neutron star matter (R and rg are circumferential and gravitational radii, respectively). We demonstrate that the data on the Cassiopeia A neutron star can be explained in terms of three parameters: f?, the neutrino cooling efficiency with respect to the standard candle; the compactness x; and the amount of light elements in the heat-blanketing envelope. For an ordinary (iron) heat-blanketing envelope or a low-mass (? 10?13 M?) carbon envelope, we find the efficiency f?? 1 (standard cooling) for x? 0.5 and f?? 0.02 (slower cooling) for a maximum compactness x? 0.7. A heat blanket containing the maximum mass (?10?8 M?) of light elements increases f? by a factor of 50. We also examine the (unlikely) possibility that the star is still thermally non-relaxe
HMOX1 gene promoter alleles and high HO-1 levels are associated with severe malaria in Gambian children.
Full text linkHeme oxygenase 1 (HO-1) is an essential enzyme induced by heme and multiple stimuli associated with critical illness. In humans, polymorphisms in the HMOX1 gene promoter may influence the magnitude of HO-1 expression. In many diseases including murine malaria, HO-1 induction produces protective anti-inflammatory effects, but observations from patients suggest these may be limited to a narrow range of HO-1 induction, prompting us to investigate the role of HO-1 in malaria infection. In 307 Gambian children with either severe or uncomplicated P. falciparum malaria, we characterized the associations of HMOX1 promoter polymorphisms, HMOX1 mRNA inducibility, HO-1 protein levels in leucocytes (flow cytometry), and plasma (ELISA) with disease severity. The (GT)(n) repeat polymorphism in the HMOX1 promoter was associated with HMOX1 mRNA expression in white blood cells in vitro, and with severe disease and death, while high HO-1 levels were associated with severe disease. Neutrophils were the main HO-1-expressing cells in peripheral blood, and HMOX1 mRNA expression was upregulated by heme-moieties of lysed erythrocytes. We provide mechanistic evidence that induction of HMOX1 expression in neutrophils potentiates the respiratory burst, and propose this may be part of the causal pathway explaining the association between short (GT)(n) repeats and increased disease severity in malaria and other critical illnesses. Our findings suggest a genetic predisposition to higher levels of HO-1 is associated with severe illness, and enhances the neutrophil burst leading to oxidative damage of endothelial cells. These add important information to the discussion about possible therapeutic manipulation of HO-1 in critically ill patients
Determination of L X-ray fluorescence parameters for Ho, Lu, W, Hg and Bi
No full textIn this work, L X-ray fluorescence cross sections, L sub-shell fluorescence yields and level widths and radiative vacancy transfer probabilities of L sub-shells to Mi, Ni and Oi sub-shells were measured for the elements Ho, Lu, W, Hg and Bi. Energy dispersive X-ray fluorescence (EDXRF) technique was used to measure L X-ray photons. To obtain related parameters, we used 59.54keV gamma photons of 241Am radioactive point source. Emitted L X-ray photons from targets were collected by means of a Si(Li) detector with resolution of 180eV at 5.9keV. The present results are generally in a good agreement with theoretical calculations and the other results obtained in the literature, within their range considering experimental uncertainty
Determination of L X-ray fluorescence parameters for Ho, Lu, W, Hg and Bi
No full textIn this work, L X-ray fluorescence cross sections, L sub-shell fluorescence yields and level widths and radiative vacancy transfer probabilities of L sub-shells to Mi, Ni and Oi sub-shells were measured for the elements Ho, Lu, W, Hg and Bi. Energy dispersive X-ray fluorescence (EDXRF) technique was used to measure L X-ray photons. To obtain related parameters, we used 59.54keV gamma photons of 241Am radioactive point source. Emitted L X-ray photons from targets were collected by means of a Si(Li) detector with resolution of 180eV at 5.9keV. The present results are generally in a good agreement with theoretical calculations and the other results obtained in the literature, within their range considering experimental uncertainty
Origin of the Placer Gold of the Barkerville Area, Cariboo District, British Columbia, Canada:
Full text linkW. L. Uglow and W. A. Johnston.In: Economic Geology. -- Vol. 18. no 6 (1923)
Populationsgenetische Differenzierung beim Eichenwickler (Tortrix viridana L.) und seiner Wirtspflanze (Quercus robur L.) anhand nukleärer Genmarker
No full textIn Western Europe pedunculate oak (Quercus robur L.) is the forest tree with the highest number of phytophagous insect species (Yela & Lawton 1997). One of these, the green oak leaf roller Tortrix viridana L. is an oligophagous herbivorous moth with a host range limited to the genus Quercus (Hunter 1990, Du Merle 1999). During outbreaks, T. viridana often leads to defoliation of oaks in spring. The abundance of T. viridana is subject to the population size fluctuations typical for herbivorous insects, where periods of small population sizes (latent periods) alternate with periods of high population sizes (outbreak) (e.g. Schütte 1957, Horstmann 1984). Apart from many experimental studies on population dynamics of the moth (e.g. Hunter 1990, Du Merle 1999, Ivashov & al. 2002) so far little attention has been paid to the genetic variation within the species as an important aspect of the genetics of this host-parasite interaction. Simchuk & al. (1999) found changes in the heterozygosity level of different isozyme loci during outbreaks in T. viridana and molecular markers for T. viridana have been developed for analyses of genetic variation within and among populations (Schroeder & Scholz 2005). But, investigations of genetic variation within and among populations of forest pest species are important to predict future pest outbreaks. So far the processes outbreaks based on are not entirely clarified, however it is known that migration plays a major role. Using molecular markers investigations of the genetic variation are possible and offer the opportunity to analyse distribution events. In this paper first results are presented concerning the genetic variation of the green oak leaf roller at three geographic scales: (1) among trees within a population, (2) among populations at a small spatial scale of about 150 km and (3) among populations at a broader geographic scale up to 3000 km. Furthermore results of the genetic variation of oaks at the small spatial scale are represented.Populationen des grünen Eichenwicklers (Tortrix viridana L., Lepidoptera: Tortricidae) und der Stieleiche (Quercus robur L., Fagaceae) wurden auf genetische Differenzierungen mit Hilfe von Kern-DNA-Markern untersucht. Insgesamt wurden 14 Eichenbestände in Nordrhein-Westfalen (NRW) und 7 weitere in verschiedenen Regionen Europas in die Untersuchung einbezogen. Weder für die Eiche noch für den Eichenwickler sind genetische Differenzierungen der Populationen auf einer kleinen geographischen Skala (etwa 150 km) nachweisbar, jedoch zeigen die Eichenpopulationen eine zunehmende genetische Distanz mit zunehmender geographischer Distanz. Für den Eichenwickler konnten innerhalb von Populationen in einem Radius von etwa 40 m Familienstrukturen ermittelt werden und auf einer kontinentalen Skala lassen sich die Ergebnisse für den Eichenwickler mit einer „isolation by distance“ erklären
Związek wariantów genetycznych β-laktoglobuliny i κ-kazeiny z zawartością wybranych białek serwatkowych w mleku krów różnych ras
Full text linkThe aim of the study was to determine the relationship of β-lactoglobulin (BLG) and κ-casein (CSN3) genetic variants with the content of selected whey proteins in milk of cows of two breeds. The research included blood and milk samples taken from 213 cows of four breeds, in that two of high-productivity: Polish Holstein-Friesian Black and White variety (PHF HO, n = 63) and Jersey (JE, n = 50), and two native breeds: Polish Red (RP, n = 50) and White-backed (BG, n = 50). The β-lactoglobulin and κ-casein genotypes were determined by PCR-RFLP. The RP-HPLC method was used for whey protein content (α-lactalbumin, β-lactoglobulin, bovine serum albumin (BSA) and lactoferrin) determination in 558 milk samples. It was shown that RP cows produced milk with a higher content of β-lactoglobulin (0.47 g/l) and α-lactalbumin (0.18 g/l) compared to PHF HO. In the case of milk obtained from BG cows, the differences were 0.49 and 0.16 g/l, respectively. Lactoferrin content was also definitely higher in the milk of RP and BG cows. It was proved that the presence of A BLG allele was associated with a higher β-lactoglobulin content in milk and lower lactoferrin at the same time. However, the presence of A allele CSN3 was connected with a higher concentration of β-lactoglobulin and α-lactalbumin. No correlation was found between BLG and CSN3 polymorphic forms and BSA content.Celem badań było określenie związku wariantów genetycznych β-laktoglobuliny (BLG) i κ-kazeiny (CSN3) z zawartością wybranych białek serwatkowych w mleku krów czerech ras. Materiał do badań stanowiły próby krwi i mleka pobrane od 213 krów 4 ras, w tym dwóch wysokoprodukcyjnych: polskiej holsztyńsko-fryzyjskiej odmiany czarno-białej (PHF HO, n = 63) i jersey (JE, n = 50) oraz dwóch ras rodzimych: polskiej czerwonej (RP, n = 50) i białogrzbietej (BG, n = 50). Genotypy β-laktoglobuliny i κ-kazeiny oznaczono metodą PCR-RFLP. Oceniono 558 próbek mleka, w których oznaczono zawartość białek serwatkowych (α-laktoalbuminy, β-laktoglobuliny, albuminy serum (BSA) i laktoferyny) przy zastosowaniu wysokosprawnej chromatografii cieczowej w odwróconym układzie faz (RP-HPLC). Wykazano, że krowy RP produkowały mleko o większej zawartości β-laktoglobuliny (o 0,47 g/l) i α-laktoalbuminy (o 0,18 g/l) w porównaniu z PHF HO. W przypadku mleka krów rasy BG różnice te wynosiły odpowiednio: 0,49 i 0,16 g/l. W odniesieniu do laktoferyny również stwierdzono zdecydowanie większą zawartość tego białka w mleku krów ras RP i BG. Wykazano, że obecność allelu A BLG była zawiązana z większą zawartością β-laktoglobuliny w mleku i jednocześnie niższą laktoferyny. Obecność allelu A CSN3 łączyła się natomiast z wyższą koncentracją β-laktoglobuliny oraz α-laktoalbuminy. Nie wykazano zależności między formami polimorficznymi BLG i CSN3 a zawartością BSA
- …
