Sedimentation History of Lago Guayabal, Puerto Rico, 1913-2001

USGS Publications Warehouse

Soler-López, Luis R.

2003-01-01

The Lago Guayabal dam, located in the municipality of Villalba in southern Puerto Rico, was constructed in 1913 for irrigation of croplands in the southern coastal plains and is owned and operated by the Puerto Rico Electric Power Authority. The reservoir had an original storage capacity of 11.82 million cubic meters and a drainage area upstream of the dam of 112 square kilometers. Sedimentation has reduced the storage capacity to 6.12 million cubic meters in 2001, which represents a storage loss of about 48 percent. However, the actual sediment accumulation in the reservoir during the 88 years is greater, because some sediment removal was conducted between 1940 and 1948 by dredging and sluicing. This report summarizes the historical data from a 1913 land survey and eight bathymetric surveys conducted between 1914 and 2001, and the relation of high sedimentation to agricultural land practices within the Lago Guayabal basin and six major hurricanes which made landfall on the island. The reservoir had an area-normalized sedimentation rate of about 1,863 cubic meters per square kilometer per year between 1913 and 1936 from a 112 square kilometer basin. In 1972, a new dam upstream along the Rio Toa Vaca impounded runoff from 57.5 square kilometers, and sediment transport to Lago Guayabal was reduced. A comparison of bathymetric survey results between 1972 and 2001 indicates an area-normalized sedimentation rate of 1,120 cubic meters per square kilometer per year or about 60 percent of the rate between 1913 and 1936. The significant reduction (almost half) of the sedimentation rate after the Toa Vaca dam was built may indicate that erosion susceptibility of the Rio Toa Vaca watershed is about twice that of the Rio Jacaguas watershed impounded by Lago Guayabal.

Public-private mix for TB and TB-HIV care in Lagos, Nigeria.

PubMed

Daniel, O J; Adedeji Adejumo, O; Abdur-Razzaq, H A; Ngozi Adejumo, E; Salako, A A

2013-09-01

Private and public tuberculosis (TB) treatment centres in Lagos State, Nigeria. To assess the contribution of private health care providers to TB and TB-HIV (human immunodeficiency virus) case finding in Lagos State. A retrospective review of programme data submitted to the Lagos State TB and Leprosy Control Programme in 2011 by public, private for-profit (PFP) and private not-for-profit (PNFP) health care providers. A total of 8425 TB cases were notified by 31 private (11 PFP and 20 PNFP) and 99 public health facilities in Lagos State. Overall, the private facilities were responsible for 10.3% (866/8425) of the total TB cases notified. The proportion of TB patients tested for HIV was respectively 86.2%, 53.1% and 96.5% among public, PFP and PNFP facilities. Overall, 22.4% of the TB patients were HIV-positive. The HIV positivity rate among public, PFP and PNFP facilities was respectively 23.8%, 7.8% and 9.9%. Uptake of cotrimoxazole preventive therapy was respectively 69.6%, 25% and 38.2% among public, PFP and PNFP facilities, while that of antiretroviral therapy was respectively 23.8%, 8.3% and 9.1% in public, PFP and PNFP facilities. There is a need to scale up collaboration with the private sector, and particularly PNFP health providers.

Sedimentation survey of Lago Dos Bocas, Utuado, Puerto Rico, January 2010

USGS Publications Warehouse

Soler-López, Luis R.

2014-01-01

Lago Dos Bocas reservoir was completed in 1942 to provide water for hydroelectric power generation along the northern coast of Puerto Rico. The reservoir had an original storage capacity of 37.50 million cubic meters (Mm3). The dam is located about 9 kilometers (km) northeast of the town of Utuado, immediately downstream of the original confluence of the Río Grande de Arecibo and the Río Caonillas (fig. 1). The Puerto Rico Electric Power Authority (PREPA) owns and operates the Lago Dos Bocas reservoir, and since 1996, the reservoir has become an essential part of the Puerto Rico Aqueduct and Sewer Authority (PRASA) North Coast Superaqueduct Project. The Superaqueduct is supplied by controlled releases for hydroelectric power generation that replenish the public-supply raw-water intake pool located about 10 km downstream from the Lago Dos Bocas Dam (fig. 1). As of 2005, the Superaqueduct supplies about 4.03 cubic meters per second (m3/s) (348,192 cubic meters per day [m3/d]) of potable water to communities along the northern coast, from Arecibo to the San Juan metropolitan area. Because of the importance of the reservoir to the North Coast Superaqueduct, the U.S. Geological Survey (USGS), in cooperation with PRASA, conducted a sedimentation survey of Lago Dos Bocas in January 2009. The results of this survey were used to estimate the useful life and the firm yield of the reservoir, and evaluate the need to dredge the reservoir.

Analysis of Management Practices in Lagos State Tertiary Institutions through Total Quality Management Structural Framework

ERIC Educational Resources Information Center

AbdulAzeez, Abbas Tunde

2016-01-01

This research investigated total quality management practices and quality teacher education in public tertiary institutions in Lagos State. The study was therefore designed to analyse management practices in Lagos state tertiary institutions through total quality management structural framework. The selected public tertiary institutions in Lagos…

Lagos bat virus transmission in an Eidolon helvum bat colony, Ghana.

PubMed

Freuling, Conrad M; Binger, Tabea; Beer, Martin; Adu-Sarkodie, Yaw; Schatz, Juliane; Fischer, Melina; Hanke, Dennis; Hoffmann, Bernd; Höper, Dirk; Mettenleiter, Thomas C; Oppong, Samual K; Drosten, Christian; Müller, Thomas

2015-12-02

A brain sample of a straw-coloured fruit bat (Eidolon helvum) from Ghana without evident signs of disease tested positive by generic Lyssavirus RT-PCR and direct antigen staining. Sequence analysis confirmed the presence of a Lagos bat virus belonging to phylogenetic lineage A. Virus neutralization tests using the isolate with sera from the same group of bats yielded neutralizing antibodies in 74% of 567 animals. No cross-neutralization was observed against a different Lagos bat virus (lineage B). Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of rare earth elements in groundwater of Lagos and Ogun States, Southwest Nigeria.

PubMed

Ayedun, H; Arowolo, T A; Gbadebo, A M; Idowu, O A

2017-06-01

Rare earth elements in our environment are becoming important because of their utilization in permanent magnets, lamp phosphors, superconductors, rechargeable batteries, catalyst, ceramics and other applications. This study was conducted to evaluate the level of rare earth elements (REE) and the variability of their anomalous behavior in groundwater samples collected from Lagos and Ogun States, Southwest, Nigeria. REE concentrations were determined in 170 groundwater samples using inductively coupled plasma-mass spectrometry, while the physicochemical parameters were determined using standard methods. Lagos State groundwater is enriched with REE [sum REEs range (mean ± SD)]; [0.365-488 (69.5 ± 117)] µg L -1 than Ogun State groundwater [sum REEs range (mean ± SD)]; [1.14-232 (22.6 ± 41.1)] µg L -1 . Boreholes are more enriched with REEs than wells. Significant (P < 0.05) positive correlation (R = Pearson) was recorded in Lagos State groundwater between sum REEs and Fe (R = 0.55). However, there were no significant correlations between sum REEs, pH (R = 0.073) and HCO 3 2- (R = 0.157) in Ogun State groundwater. Chondrite-normalized plot shows that Lagos groundwater exhibits positive Ce anomaly, while Ogun State groundwater does not. The source of REE in Lagos State may be from the ocean and leaching from wastes dumpsites, while the source in Ogun State groundwater may be from the rocks.

The effects of Hurricane Hugo on suspended-sediment loads, Lago Loiza Basin, Puerto Rico

USGS Publications Warehouse

Gellis, A.

1993-01-01

In the two main tributaries that enter Lago Loiza, Rio Grande de Loiza and Rio Gurabo, 99 600 tonnes of suspended sediment was transported by 58.2??106 m3 of runoff in a 48 h period. The storm-average suspended-sediment concentration in the Rio Grande de Loiza for Hurricane Hugo was 2290 mgl-1, the second lowest for the 12 storms that have been monitored at this site. In Rio Gurabo the storm-average suspended-sediment concentration was 1420 mg l -1, the sixth lowest recorded out of 15 monitored storms. In Quebrada Salvatierra, a small tributary to Rio Grande de Loiza, suspended-sediment concentrations were as low as 33 mg l-1 during peak runoff of 20m3s-1. Normally the suspended-sediment concentrations at this discharge are 300 mg l-1. Hurricane force winds seem to be the most important factor contributing to the lower than expected suspended-sediment loads. High winds caused vegetation and debris to be dislodged and displaced. Debris accumulated on hillslopes and in small channels, blocked bridges and formed debris dams. These dams caused local backwater effects that reduced stream velocities and decreased suspended-sediment loads. -from Author

Climatology of equatorial stratosphere over Lagos, Nigeria

NASA Astrophysics Data System (ADS)

Oyekola, Oyedemi Samuel

We have used 12 complete calendar years (January 1993-December 2004) of monthly averages of measurements made by the Dobson spectrophotometer instrument over an urban site, Lagos (6.6oN, 3.3oE), southwest Nigeria, to study equatorial stratospheric column ozone variations and trends. Our results indicate that the time-averaged total column ozone has a seasonal cy-cle, which maximizes in June and July with a value of 259 Dobson units (DU) and minimizes in February with a magnitude of 250 DU. Statistical analysis of the climatological mean monthly total Dobson O3 record for 1993-2004 show that the local trend is approximately +0.041±0.0011 DU/year (+0.49±0.013% per decade). Spectral analysis was applied to the monthly averages series. The significant periodicity at 95% confidence level demonstrate prominent spectra peaks near 1.9 and 3.6 years, representative of quasi-biennial oscillation (QBO) and quasi-triennial oscillation (QTO), respectively. Signal due to semiannual variation is also identified at Lagos sounding site. Comparison with the ozone observations from Total Ozone Mapping Spectrom-eter (TOMS) on board the Earth-Probe (EP) satellite for the period from 1997 to 2002 reveal that EP/TOMS instrument consistently larger than the ground-based measurement from Dob-son station. Percentage mean relative disparity ranges from -11% to 15%. The root mean square error (RMSE) between satellite and ground-based observations over Lagos ranges be-tween ˜35-83 DU with largest and lowest variability occurring during the ascending phase of solar activity (1999, 10.7 cm radio flux, F10.7 equals 154 flux units) and during the peak phase of solar activity (2001, F10.7 equals 181), respectively.

Assessment of communication skills among Pharmacy students of the University of Lagos, Lagos, Nigeria

PubMed Central

Aina, BA; Ogunbiyi, OO

2011-01-01

BACKGROUND: Communication skill is the bridge between the pharmacists and the patient. Communication in health can contribute to all aspects of disease prevention and health promotion. In order to become successful pharmacists, one needs to possess excellent communication skills to serve clients. This study was conducted at the University of Lagos to assess communication skills of Pharmacy students. METHOD: The study was descriptive and cross sectional. It was carried out between May and July 2009. Questionnaires were used for data collection. The questionnaire had two sections - the bio data section and pre-formulated questions on communication skills which has three options and one of these is the best option. RESULTS: A total number of 125 respondents were involved in the study which included 25 students from 200level, 50 from 300level and 50 from 500 level. Majority of them were between 18-25 years old (89.6%). There were more females (71.2%) than males (28.8%). Also most of them were Christians (71.2%). Among the respondents, about 62% picked the best options as their answer while the rest picked other options. There was no statistical difference in the choice of best options between the different levels of study. CONCLUSIONS: It can be concluded from the results of this study that majority of Pharmacy Students at the University of Lagos had good communication skills and they will be able to discharge their duties as pharmacists when they eventually graduate. PMID:24826026

Influence of Counselling Services on Perceived Academic Performance of Secondary School Students in Lagos State

ERIC Educational Resources Information Center

Bolu-Steve, Foluke; Oredugba, Oluwabunmi Olayinka

2017-01-01

This study aimed at looking at the influence of counseling services on perceived academic performance of secondary school students in Lagos State. At the first stage, the researchers purposively selected Ikorodu L.G.A in Lagos State. At the researchers selected two schools (1 Private schools, & 1 Public schools), using simple random technique.…

The Geologic and Geochemical Setting of Lago Fagnano, Tierra del Fuego, Argentina

NASA Astrophysics Data System (ADS)

Tingle, D.; Odle, K.; Knettel, P.; Redding, S.; Perry, E.; Ellins, K.; Ormiston, C.; Dovzak, N.; Anderson, S.

2005-12-01

Lago Fagnano, Tierra del Fuego, Argentina is the largest and southernmost ice-free lake on Earth. The isolated lake is unique because the geographic and geologic context provides information relating to the westerly wind patterns, interaction of multiple water sources (hot springs, glacial meltwater, precipitation, groundwater), and tectonic dynamics along a major transform fault. In March, 2005, four students and three teachers from Boerne High School, south-central Texas joined scientists from the United States, Argentina and Switzerland engaged in a geophysical survey of this lake. Lago Fagnano potentially contains within its sediments an undisturbed record of the geotectonic and global climate variability of past 20,000 years. The science team imaged the lake floor with a boat specially equipped to collect both high resolution data (high frequency), imaging the upper 10-15 meters of the sediment, and long range data (low frequency), penetrating 100 or more meters into the sediment. The group conducted field research of existing tectonic features at the eastern end of Tierra del Fuego, an activity directly tied to the research objectives of the science team. They also collected water and soil samples to assess chemical and isotopic trends in the Lago Fagnano region. The research performed can help to characterize the modern geochemical setting of the lake. Analyses of dissolved oxygen, NH4+, PO42-, pH (water) and N, P, and pH (soils) demonstrate a link between low nutrient levels and low biodiversity (which was confirmed by observation) in Tierra del Fuego. Water and soil data are incorporated into a database to facilitate comparisons to North American samples collected and analyzed during the Boerne High School summer field courses. Twenty-three ^18O and ^D analyses yielded a south-north isotopic trend across the Lago Fagnano region. ^18O and ^D transition from -11.92 to -3.53% and -87.81 to -40.26%, respectively, moving south to the Beagle Channel. These

Within salvation: girl hawkers and the colonial state in development era Lagos.

PubMed

George, Abosede

2011-01-01

For almost two decades between the close of the Second World War and Nigerian independence in 1960, the British colonial state which faced a crisis of legitimacy in Lagos upheld city ordinances that made itinerant trading by young children in Lagos a punishable status offense. Although anti-trading regulations were gender-neutral in their language, girls were disproportionately sanctioned for engaging in street trading and related activities. In defending their concentration on girl sellers over boy sellers, colonial welfare officials painted a picture of the urban context as an inherently dangerous context and of girls as being particularly at risk of violent assault in the city, making them particularly in need of protection from town life. Sources which show that parents generally resisted or ignored the street trading regulations and continued permitting their daughters to sell despite entreaties, warnings, or fines from colonial officials, suggest that African parents and British colonial officials may have had conflicting views on the inherent danger of the city, on what constituted child endangerment, and on the gendered nature of childhood. This article argues that the girl saving campaigns of development era Lagos were as much about the legitimization of a colonial state facing a crisis of legitimacy as they were about debates between African parents and colonial welfare officials in Lagos concerning ideas of children and childhood and the dangers of street trading by African girls.

Using satellite images to monitor glacial-lake outburst floods: Lago Cachet Dos drainage, Chile

USGS Publications Warehouse

Friesen, Beverly A.; Cole, Christopher J.; Nimick, David A.; Wilson, Earl M.; Fahey, Mark J.; McGrath, Daniel J.; Leidich, Jonathan

2015-01-01

During 2008–2013, 14 GLOFs were released from Lago Cachet Dos and created environmental and safety concerns for downstream residents and to infrastructure. If GLOFs and the consequent headward erosion continue, the moraine that creates Lago Cachet Uno could be destabilized and breached, and the two lakes could merge. If the two lakes become connected, the volume of future GLOFs likely would be greater and thus cause longer and (or) more extensive flooding downstream. Additional GLOFs from Lago Cachet Dos are expected in the future, and continued environmental monitoring could provide an early warning system as well as scientific information that could increase our understanding of GLOFs and their consequences. GLOFs occur in glaciated areas around the world and remote sensing technologies can allow researchers to better understand—and potentially predict—future GLOF events.

Calibration of a large water-Cherenkov detector at the Sierra Negra site of LAGO

NASA Astrophysics Data System (ADS)

Galindo, A.; Moreno, E.; Carrasco, E.; Torres, I.; Carramiñana, A.; Bonilla, M.; Salazar, H.; Conde, R.; Alvarez, W.; Alvarez, C.; Araujo, C.; Areso, O.; Arnaldi, H.; Asorey, H.; Audelo, M.; Barros, H.; Bonnett, M.; Calderon, R.; Calderon, M.; Campos-Fauth, A.; Carramiñana, A.; Carrasco, E.; Carrera, E.; Cazar, D.; Cifuentes, E.; Collogo, D.; Conde, R.; Cotzomi, J.; Dasso, S.; De Castro, A.; De La Torre, J.; De León, R.; Estupiñan, A.; Galindo, A.; García, L.; Gomez Berisso, M.; González, M.; Guevara, W.; Gulisano, A. M.; Hernández, H.; Jaimes, A.; López, J.; Mantilla, C.; Martín, R.; Martinez-Mendez, A.; Martínez, O.; Martins, E.; Macías-Meza, J. J.; Mayo-García, R.; Melo, T.; Mendoza, J.; Miranda, P.; Montes, E.; Morales, E.; Morales, I.; Moreno, E.; Murrugarra, C.; Nina, C.; Núñez, L. A.; Núñez-Castiñeyra, A.; Otiniano, L.; Peña-Rodríguez, J.; Perenguez, J.; Pérez, H.; Pérez, Y.; Pérez, G.; Pinilla-Velandia, S.; Ponce, E.; Quishpe, R.; Quispe, F.; Ramelli, M.; Reyes, K.; Rivera, H.; Rodriguez, J.; Rodríguez-Ferreira, J.; Rodríguez-Pascual, M.; Romero, M.; Rubio-Montero, A. J.; Salazar, H.; Salinas, J.; Sarmiento-Cano, C.; Sidelnik, I.; Sofo Haro, M.; Suárez-Durán, M.; Subieta, M.; Tello, J.; Ticona, R.; Torres, I.; Torres-Niõ, L.; Truyenque, J.; Valencia-Otero, M.; Vargas, S.; Vásquez, N.; Villaseñor, L.; Zamalloa, M.; Zavala, L.; LAGO Collaboration

2017-07-01

The Latin American Giant Observatory (LAGO) is an international network of water-Cherenkov detectors (WCD) set in different sites across Latin America. On top of the Sierra Negra volcano in Mexico at an altitude of 4530 m, LAGO has completed its first out of three instrumented detector. It consists of a cylindrical water tank with a diameter of 7.3 m and a height of 1 m and a total detection area of 40 m2 that is sectioned in four equal slices. In this work we present the full calibration procedure of this detector and the initial measurements of stability in rate. We also derive the effective area to gamma-ray bursts for the complete array using the LAGO simulation chain, based on CORSIKA and GEANT4.

The data acquisition system of the Latin American Giant Observatory (LAGO)

NASA Astrophysics Data System (ADS)

Sofo Haro, M.; Arnaldi, L. H.; Alvarez, W.; Alvarez, C.; Araujo, C.; Areso, O.; Arnaldi, H.; Asorey, H.; Audelo, M.; Barros, H.; Bertou, X.; Bonnett, M.; Calderon, R.; Calderon, M.; Campos-Fauth, A.; Carramiñana, A.; Carrasco, E.; Carrera, E.; Cazar, D.; Cifuentes, E.; Cogollo, D.; Conde, R.; Cotzomi, J.; Dasso, S.; De Castro, A.; De La Torre, J.; De León, R.; Estupiñan, A.; Galindo, A.; Garcia, L.; Gómez Berisso, M.; González, M.; Guevara, W.; Gulisano, A. M.; Hernández, H.; Jaimes, A.; López, J.; Mantilla, C.; Martín, R.; Martinez-Mendez, A.; Martínez, O.; Martins, E.; Masías-Meza, J. J.; Mayo-García, R.; Melo, T.; Mendoza, J.; Miranda, P.; Montes, E.; Morales, E.; Morales, I.; Moreno, E.; Murrugarra, C.; Nina, C.; Núñez, L. A.; Núñez-Castiñeyra, A.; Otiniano, L.; Peña-Rodríguez, J.; Perenguez, J.; Pérez, H.; Perez, Y.; Perez, G.; Pinilla-Velandia, S.; Ponce, E.; Quishpe, R.; Quispe, F.; Reyes, K.; Rivera, H.; Rodriguez, J.; Rodríguez-Pascual, M.; Romero, M.; Rubio-Montero, A. J.; Salazar, H.; Salinas, J.; Sarmiento-Cano, C.; Sidelnik, I.; Haro, M. Sofo; Suárez-Durán, M.; Subieta, M.; Tello, J.; Ticona, R.; Torres, I.; Torres-Niño, L.; Truyenque, J.; Valencia-Otero, M.; Vargas, S.; Vásquez, N.; Villasenor, L.; Zamalloa, M.; Zavala, L.

2016-06-01

LAGO is an extended cosmic ray observatory composed of water-Cherenkov detectors (WCD) placed throughout Latin America. It is dedicated to the study of various issues related to astrophysics, space weather and atmospheric physics at the regional scale. In this paper we present the design and implementation of the front-end electronics and the data acquisition system for readout of the WCDs of LAGO. The system consists of preamplifiers and a digital board sending data to a computer via an USB interface. The analog signals are acquired from three independent channels at a maximum rate of ~1.2×105 pulses per second and a sampling rate of 40 MHz. To avoid false trigger due to baseline fluctuations, we present in this work a baseline correction algorithm that makes it possible to use WCDs to study variations of the environmental radiation. A data logging software has been designed to format the received data. It also enables an easy access to the data for an off-line analysis, together with the operational conditions and environmental information. The system is currently used at different sites of LAGO.

[Water quality evaluation in rural areas of Lavras, Minas Gerais, Brazil, 1999-2000].

PubMed

Rocha, Christiane Maria Barcellos Magalhães da; Rodrigues, Luciano Dos Santos; Costa, Claudionor C; de Oliveira, Paulo Roberto; da Silva, Israel José; de Jesus, Eder Ferreira Moraes; Rolim, Renata G

2006-09-01

In addition to personal interviews, laboratory analyses were performed using 80 water samples from 45 rural areas that are crossed by the Agua Limpa and Santa Cruz streams close to the city of Lavras, southern Minas Gerais State. The results allowed comparing the quality of water used for agriculture and the identification of determinant factors. The Agua Limpa stream mostly crosses an area used primarily for housing and characterized by low schooling. Many houses are supplied by shallow water wells and have ordinary cesspits for human waste disposal. All springs are polluted. The Santa Cruz stream displays a different scenario. The land is used mostly for agricultural purposes. Most owners live in town, with widely varied levels of school, from none to university. The houses are supplied by surface water. Most of the springs are polluted. The perception by both home and land owners concerning quality of the drinking water is determined solely by the water's physical and organoleptic characteristics. Sanitary parameters are not taken into account. Moreover, there is no relationship between fecal contamination and the type of spring. Land use and anthropic activity are far more important than the type of spring for water quality.

Assessing the deep drilling potential of Lago de Tota, Colombia, with a seismic survey

NASA Astrophysics Data System (ADS)

Bird, B. W.; Wattrus, N. J.; Fonseca, H.; Velasco, F.; Escobar, J.

2015-12-01

Reconciling orbital-scale patterns of inter-hemispheric South American climate during the Quaternary requires continuous, high-resolution paleoclimate records that span multiple glacial cycles from both hemispheres. Southern Andean Quaternary climates are represented by multi-proxy results from Lake Titicaca (Peru-Bolivia) spanning the last 400 ka and by pending results from the Lago Junin Drilling Project (Peru). Although Northern Andean sediment records spanning the last few million years have been retrieved from the Bogota and Fúquene Basins in the Eastern Cordillera of the Colombian Andes, climatic reconstructions based on these cores have thus far been limited to pollen-based investigations. When viewed together with the Southern Hemisphere results, these records suggest an anti-phased hemispheric climatic response during glacial cycles. In order to better assess orbital-scale climate responses, however, independent temperature and hydroclimate proxies from the Northern Hemisphere are needed in addition to vegetation histories. As part of this objective, an effort is underway to develop a paleoclimate record from Lago de Tota (3030 m asl), the largest lake in Colombia and the third largest lake in the Andes. One of 17 highland tectonic basins in Eastern Cordillera, Lago de Tota formed during Tertiary uplift that deformed pre-foreland megasequences, synrift and back-arc megasequences. The precise age and thickness of sediments in the Lago de Tota basin has not previously been established. Here, we present results from a recent single-channel seismic reflection survey collected with a small (5 cubic inch) air gun and high-resolution CHIRP sub-bottom data. With these data, we examine the depositional history and sequence stratigraphy of Lago de Tota and assess its potential as a deep drilling target.

Sedimentation survey of Lago Lucchetti, Yauco, Puerto Rico, September 2013–May 2014

USGS Publications Warehouse

Gómez-Fragoso, Julieta

2016-08-23

The U.S. Geological Survey conducted a sedimentation survey of Lago Lucchetti, Yauco, Puerto Rico, in 2013–14 in cooperation with the Puerto Rico Aqueduct and Sewer Authority. The survey updated a previous survey, conducted in 2000, and provided accurate information regarding reservoir storage capacity and sedimen­tation rate using bathymetric techniques and a global positioning system coupled with a depth sounder device. The results of the 2013–14 survey indicated a total storage capacity for Lago Lucchetti of 10.21 million cubic meters and a long­-term sedimentation rate loss of 0.16 million cubic meters per year based on the original capacity in 1952. Sediment accumulation was about 10.14 million cubic meters over the life of the reservoir, which represents a storage decrease of about 50 percent of the original capacity in 1952. On the basis of a comparison between the 2013–14 and 2000 surveys, the useful life for Lago Lucchetti is projected to end in 2076.

Geology, petrology and geochronology of the Lago Grande layered complex: Evidence for a PGE-mineralized magmatic suite in the Carajás Mineral Province, Brazil

NASA Astrophysics Data System (ADS)

Teixeira, Antonio Sales; Ferreira Filho, Cesar Fonseca; Giustina, Maria Emilia Schutesky Della; Araújo, Sylvia Maria; da Silva, Heloisa Helena Azevedo Barbosa

2015-12-01

ultramafic lithotypes render Nd model ages between 2.94 and 3.56 Ga, with variably negative ɛNd (T = 2.72 Ga) values (-0.32 to -4.25). The crystallization sequence of the intrusion and the composition of cumulus minerals, together with lithogeochemical and Nd isotopic results, are consistent with an original mantle melt contaminated with older continental crust. The contamination of mafic magma with sialic crust is also consistent with intra-plate rifting models proposed in several studies of the CMP. Lithogeochemical and isotopic data from the Lago Grande Complex may also be interpreted as the result of melting an old lithospheric mantle, and alternative models should not be disregarded. PGE mineralizations occur in chromitites and associated with base metal sulfides in the Lago Grande Complex. Chromitite has the highest PGE content (up to 10 ppm) and is characterized by high Pt/Pd ratio (4.3). Mantle-normalized profile of chromitite is highly enriched in PPGE and similar to those from Middle Group (MG) and Upper Group (UG) chromitites from the Bushveld Complex. Platinum group minerals (PGM) occur mainly at the edge of chromite crystals in the Lago Grande chromitite, consisting of arsenides and sulfo-arsenides. Sulfide-bearing harzburgite samples of the Lago Grande complex have PGE content of up to 1 ppm and low Pt/Pd (0.2-0.3) ratios. The 2722 ± 53 Ma U-Pb zircon age determined in this study for the Lago Grande Complex overlaps with the crystallization age of the Luanga Complex. Previous interpretation that the Lago Grande and Luanga layered intrusions are part of a magmatic suite (i.e., Serra Leste Magmatic Suite) is now reinforced by similar fractionation sequences, comparable petrological evolution and overlapped U-Pb zircon ages. The occurrence of the same styles of PGE mineralization in the Lago Grande and Luanga complexes, together with remarkably similar chondrite-normalized PGE profiles and PGE minerals for chromitites of both complexes, support the concept that

Storage capacity and sedimentation trends of Lago Garzas, Puerto Rico, 1996-2007

USGS Publications Warehouse

Soler-Lopez, L.R.

2012-01-01

Lago Garzas is located in west-central Puerto Rico, about 3.5 kilometers southwest of the town of Adjuntas, in the confluence of the Río Vacas and three other unnamed tributaries (fig. 1). The dam is owned and operated by the Puerto Rico Electric Power Authority (PREPA), and was constructed in 1943 for hydroelectric power generation and municipal water use along the southern coast. The dam is a semi-hydraulic earthfill embankment lined with boulders, and has a height of 61.57 meters, a top width of 9.14 meters, a base width of 365.76 meters, and a crest length of 227.37 meters; State Road PR-518 crosses the top of the dam. A morning-glory-type spillway is located near the west abutment of the dam at an elevation of 736.12 meters above mean sea level (Puerto Rico Water Resources Authority, 1969). Figure 2 shows an aerial photograph of the Lago Garzas earthfill dam and the morning-glory spillway section. Additional information and operational procedures are provided in Soler-López and others (1999). During July 17-18, 2007, the U.S. Geological Survey (USGS) Caribbean Water Science Center, in cooperation with the Puerto Rico Aqueduct and Sewer Authority, conducted a bathymetric survey of Lago Garzas to update the reservoir storage capacity and update the reservoir sedimentation rate by comparing the 2007 data with the previous 1996 bathymetric survey results. The purpose of this report is to describe and document the USGS sedimentation survey conducted at Lago Garzas during July 2007, including the methods used to update the reservoir storage capacity, sedimentation rates, and areas of substantial sediment accumulation since 1996.

Drivers and Pattern of Social Vulnerability to Flood in Metropolitan Lagos, Nigeria

NASA Astrophysics Data System (ADS)

Fasona, M.

2016-12-01

Lagos is Africa's second largest city and a city-state in southwest Nigeria. Population and economic activities in the city are concentrated in the greater Lagos metropolitan area - a group of barrier islands less than a thousand square kilometer. Several physical factors and critical human-environmental conditions contribute to high flood vulnerability across the city. Flood impact is highly denominated and the poor tend to suffer more due to higher risk of exposure and poor adaptive capacity. In this study we present the pattern of social vulnerability to flooding across the Lagos metropolis and argued that the pattern substantially reflects the pattern and severity of flooding impact on people across the metropolis. Twenty nine social indicators and experiences including poverty profile, housing conditions, education, population and demography, social network, and communication, among others, were considered. The data were collated through field survey and subjected to principal component analysis. The results were processed into raster surfaces using GIS for social vulnerability characterization at neighborhood levels. The results suggest the social status indicators, neighborhood standing and social networks indictors, the indicators of emergency responses and security, and the neighborhood conditions, in that order, are the most important determinants of social vulnerability. Six of the 16 LGAs in metropolitan Lagos have high social vulnerability. Neighborhoods that combine poor social status indicators and poor neighborhood standing and social networks are found to have high social vulnerability whereas other poor neighborhoods with strong social networks performed better. We conclude that improved human living condition and social network and communication in poor urban neighborhoods are important to reducing social vulnerability to flooding in the metropolis.

Hourly global and diffuse radiation of Lagos, Nigeria-correlation with some atmospheric parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chendo, M.A.C.; Maduekwe, A.A.L.

1994-03-01

The influence of four climatic parameters on the hourly diffuse fraction in Lagos, Nigeria, has been studied. Using data for two years, new correlations were established. The standard error of the Liu and Jordan-type equation was reduced by 12.83% when solar elevation, ambient temperature, and relative humidity were used together as predictor variables for the entire data set. Ambient temperature and relative humidity proved to be very important variables for predicting the diffuse fraction of the solar radiation passing through the humid atmosphere of the coastal and tropic city of Lagos. Seasonal analysis carried out with the data showed improvementsmore » on the standard errors for the new seasonal correlations. In the case of the dry season, the improvement was 18.37%, whole for the wet season, this was 12.37%. Comparison with existing correlations showed that the performance of the one parameter model (namely K[sub t]), of Orgill and Hollands and Reindl, Beckman, and Duffie were very different from the Liu and Jordan-type model obtained for Lagos.« less

Nutritional status of urban and rural primary school pupils in Lagos State, Nigeria.

PubMed

Ekekezie, O O; Odeyemi, K A; Ibeabuchi, N M

2012-01-01

This study was carried out in Lagos State in Ikorodu LGA (rural), a largely agrarian area producing raw materials for agro-allied industries and Ikeja LGA (urban), a highly-developed metropolis and commercial centre. Hitherto, studies showed that undernutrition had been the main form of malnutrition among Nigerian children. However with influences from urbanization, westernization and globalization in cosmopolitan Lagos, it is imperative to find out if the global epidemic of overweight and obesity has caught on. To compare the nutritional status of primary school pupils in urban and rural LGAs in Lagos State, Nigeria. This was a cross , sectional comparative study. A multistage sampling method was adopted. Data were collected from 529 pupils with an interviewer administered questionnaire. Their weight and height were recorded in pre-designed proforma and converted to nutritional indices. The prevalence rates of underweight, stunting and wasting in the rural area were 49.6%, 50.8% and 24.2% respectively; while it was 15.1%, 16.6% and 13.6% in the urban area respectively. There was overnutrition in the urban area: 15.1% were overweight and 13.2% were obese. The mean nutritional indices were significantly lower among the rural pupils than urban pupils (p<0.001) in each case. Undernutrition is still a major health problem among school children in Lagos State, Nigeria, more so in the rural area. There is an emergence of overweight and obesity in the urban area. A comprehensive programme to improve nutritional status is recommended as part of a well funded school health programme.

Estimating urban trees and carbon stock potentials for mitigating climate change in Lagos: Case of Ikeja Government Reserved Area (GRA)

NASA Astrophysics Data System (ADS)

Elias, P. O.; Faderin, A.

2014-12-01

Urban trees are a component of the urban infrastructure which offers diverse services including environmental, aesthetic and economic. The accumulation of carbon in the atmosphere resulting from the indiscriminate distribution of human populations and urban activities with the unsustainable consumption of natural resources contributes to global environmental change especially in coastal cities like Lagos. Carbon stocks and sequestration by urban trees are increasingly recognized to play significant roles for mitigating climate change. This paper focuses on the estimation of carbon stock and sequestration through biomass estimation and quantification in Ikeja GRA, Lagos. Ikeja possesses a characteristic feature as a microcosm of Lagos due to the wide range of land uses. A canopy assessment of tree population was carried out using itree canopy software. A GPS survey was used to collect an inventory of all trees showing their location, spatial distribution and other attributes. The analysis of the carbon storage and sequestration potential of both actual and potential tree planting sites involved biomass estimations from tree allometry equations. Trees were identified at species level and measurements of their dendrometric values were recorded and integrated into the GIS database to estimate biomass of trees and carbon storage. The trees in the study area were estimated to have a biomass of 441.9 mg and carbon storage of 221.395 kg/tree. By considering the potential tree planting sites the estimated carbon stored increased to 11,352.73 kg. Carbon sequestration value in the study area was found to be 1.6790 tonnes for the existing trees and 40.707 tonnes for the potential tree planting sites (PTPS). The estimation of carbon storage and sequestration values of trees are important incentives for carbon accounting/footprints and monitoring of climate change mitigation which has implications for evaluation and monitoring of urban ecosystem.

The glacial geomorphology of the Lago Buenos Aires and Lago Puerreydón ice lobes, Central Patagonia

NASA Astrophysics Data System (ADS)

Bendle, Jacob; Thorndycraft, Varyl; Palmer, Adrian

2016-04-01

Patagonia is ideally located for reconstructions of late Quaternary ice-climate interaction(s) in the Southern Hemisphere mid-latitudes, yet many questions remain concerning post-LGM ice sheet retreat dynamics across the region. While modern-day glaciation is restricted to three small icefields (the North and South Patagonian and Cordillera Darwin icefields), during the Quaternary, and at the LGM, episodes of significant ice advance culminated in an expansive Patagonian ice sheet (PIS) centered over the southern Andes, for which a long and well-preserved landform record exists. Previous mapping in the region has either aimed to achieve regional coverage, necessarily omitting more subtle/complex features suggestive of certain ice-marginal processes, or has focused on the identification of palaeo-ice limits (e.g. moraine ridges) for geochronological applications, with little attention given to other (e.g. glaciofluvial, glaciolacustrine) features that are significant for understanding post-LGM ice sheet retreat dynamics. This poster presents a comprehensive and highly detailed (<30m spatial resolution) map of the glacial geomorphology of the Lago Buenos Aires (46.4°S) and Lago Puerreydón (47.2°S) ice lobes, major outlet glaciers of the central sector of the former PIS. The map allows refined reconstructions of glacial and, in particular, deglacial ice-marginal processes, and will underpin further analysis on the retreat history of the palaeo-ice lobes using high-resolution lithostratigraphic (varve) analyses.

Sedimentation Survey of Lago La Plata, Puerto Rico, July 2006

USGS Publications Warehouse

Soler-López, Luis R.

2008-01-01

Lago La Plata dam is located between the municipalities of Naranjito and Toa Alta in north central Puerto Rico, about 5 kilometers south of the town of Toa Alta and about 5 kilometers north of the town of Naranjito. The reservoir impounds the waters of the Rio de La Plata, the Rio Guadiana, and the Rio Ca?as, and is part of the San Juan Metropolitan Water District, which provides about 35 percent of the total water demand for the area (Soler-Lopez and others, 2000). The reservoir has a drainage area of about 469 square kilometers. The dam was constructed in 1974 and is a concrete gravity structure with a normal pool elevation of 52.00 meters above mean sea level (Puerto Rico Electric Power Authority, 1979). During October 1998, the U.S. Geological Survey (USGS), Caribbean Water Science Center, in cooperation with the Puerto Rico Aqueduct and Sewer Authority (PRASA) conducted a bathymetric survey of Lago La Plata to assess the impact of Hurricane Georges on the storage capacity of the reservoir. Between July 17 and 20, 2006, the USGS and the PRASA conducted an additional bathymetric survey of Lago La Plata to update the reservoir storage capacity and determine the reservoir sedimentation rate by comparing the 2006 survey data with the 1998 survey data.. The purpose of this report is to update the reservoir storage capacity, sedimentation rates, and areas of substantial sediment accumulation since 1998. Historical (1974) data are referenced as needed to account for long-term storage capacity loss trends...

Sedimentation Survey of Lago de Cidra, Puerto Rico, August 2007

USGS Publications Warehouse

Soler-López, Luis R.

2010-01-01

Lago de Cidra is a reservoir located on the confluence of Rio de Bayamon, Rio Sabana, and Quebrada Prieta, in the municipality of Cidra in east-central Puerto Rico, about 3.0 kilometers northeast of the town of Cidra. The dam is owned and operated by the Puerto Rico Aqueduct and Sewer Authority (PRASA), and was constructed in 1946 as a 6.54-million-cubic-meter supplemental water supply for the San Juan metropolitan area. The reservoir impounds the waters of Rio de Bayamon, Rio Sabana and Quebrada Prieta. The reservoir has a drainage area of 21.4 square kilometers. The dam is a concrete gravity and earthfill structure with a length of approximately 165 meters and a structural height of 24 meters. The spillway portion of the dam is an ungated ogee crest about 40 meters long with a crest elevation of 403.00 meters above mean sea level. Additional information and operational procedures are listed in Soler-Lopez (1999). During August 14-15, 2007, the U.S. Geological Survey (USGS), Caribbean Water Science Center (CWSC), in cooperation with the PRASA, conducted a bathymetric survey of Lago de Cidra to update the reservoir storage capacity and actualize the reservoir sedimentation rate by comparing the 2007 data with the previous 1997 bathymetric survey data. The purpose of this report is to describe and document the USGS sedimentation survey conducted at Lago de Cidra during August 2007, including the methods used to update the reservoir storage capacity, sedimentation rates, and areas of substantial sediment accumulation since 1997.

Healthcare waste management status in Lagos State, Nigeria: a case study from selected healthcare facilities in Ikorodu and Lagos metropolis.

PubMed

Longe, Ezechiel O

2012-06-01

A survey of healthcare waste management practices and their implications for health and the environment was carried out. The study assessed waste management practices in 20 healthcare facilities ranging in capacity from 40 to 600 beds in Ikorodu and metropolitan Lagos, Lagos State, Nigeria. The prevailing healthcare waste management status was analysed. Management issues on quantities and proportion of different constituents of waste, segregation, collection, handling, transportation, treatment and disposal methods were assessed. The waste generation averaged 0.631 kg bed(-1) day(-1) over the survey area. The waste stream from the healthcare facilities consisted of general waste (59.0%), infectious waste (29.7%), sharps and pathological (8.9%), chemical (1.45%) and others (0.95%). Sharps/pathological waste includes disposable syringes. In general, the waste materials were collected in a mixed form, transported and disposed of along with municipal solid waste with attendant risks to health and safety. Most facilities lacked appropriate treatment systems for a variety of reasons that included inadequate funding and little or no priority for healthcare waste management as well as a lack of professionally competent waste managers among healthcare providers. Hazards associated with healthcare waste management and shortcomings in the existing system were identified.

Lagos "Area Boys", Substance Usage and Potential Risk Factors

ERIC Educational Resources Information Center

Salaam, Abeeb Olufemi; Brown, Jennifer

2012-01-01

The current study explores the rate at which members of Lagos' "area boys" engage in drug and alcohol use, and determines the predictive roles of parental and neighbourhood characteristics in the gang patterns of psychoactive substance misuse behaviour. The study approached gang members (N = 129) aged from 18 to 38 years (M = 25.83, SD = 4.82)…

Comparison of Storage Capacity and Sedimentation Trends of Lago Guayabal, Puerto Rico-December 2001 and October 2006

USGS Publications Warehouse

Soler-López, Luis R.

2008-01-01

Lago Guayabal dam is located on the Rio Jacaguas in the municipality of Villalba in southern Puerto Rico, about 4 kilometers north of the town of Juana Diaz and about 5 kilometers south of Villalba (fig. 1). The dam is owned and operated by the Puerto Rico Electric Power Authority (PREPA) and was constructed in 1913 for the irrigation of croplands in the southern coastal plains of Puerto Rico. The reservoir impounds the waters of the Rio Jacaguas and those of the Rio Toa Vaca, when the Toa Vaca dam overflows or releases water. The reservoir has a drainage area of 53.8 square kilometers. The dam is a concrete gravity structure with a normal pool (at top of flashboards) elevation of 103.94 meters above mean sea level (Puerto Rico Electric Power Authority, 1988). During October 2006, the U.S. Geological Survey (USGS), Caribbean Water Science Center, in cooperation with the Puerto Rico Aqueduct and Sewer Authority (PRASA) conducted a bathymetric survey of Lago Guayabal to update the reservoir storage capacity and actualize the reservoir sedimentation rate by comparing the 2006 data with the previous 2001 bathymetric survey results. The purpose of this report is to describe and document the USGS sedimentation survey conducted at Lago Guayabal during October 2006, including the methods used to update the reservoir storage capacity, sedimentation rates, and areas of substantial sediment accumulation since December 2001. The Lago Guayabal sedimentation history up to 2001 was published by the USGS in 2003 (Soler-Lopez, 2003); therefore, this report focuses on the comparison between the 2001 and current bathymetric surveys of Lago Guayabal.

Arterial injuries in civilian practice in Lagos, Nigeria.

PubMed

Thomas, M O; Giwa, S O; Adekoya-Cole, T O

2005-12-01

This is a retrospective study of patients managed at the Lagos University Teaching Hospital for peripheral arterial injuries from January 1995 to April 2003. The aim was to study the pattern of peripheral arterial injuries in Lagos. Nigeria and to look at the outcome of management and see what improvements could be made in future. Data was collated from case notes of patients, operation register in theatre and admission and discharge books from the surgical wards and the data bank of consultants involved in patients' management. Forty-one patients. 37 males and 4 females. were treated within the study period (M:F ratio of 9:1). Twenty three patients (56.1%) suffered gunshot injuries during armed robbery attacks while 9 patients (22.0%) had stab injuries in civilian violence. Twenty-one patients (3 with gunshot injuries and 18 non gunshot penetrating injuries) were managed by direct suturing of vessels. Eight patients had prosthetic graft interposition while 2 patients had reversed saphenous vein grafts. Two patients had the superficial branches of their radial arteries tied up at the wrist. Gun shot injuries from armed robbery attack was the commonest cause of peripheral arterial injuries in this environment during the period of study.

Monitoring mountain lakes in a changing Alpine cryosphere: the Lago Nero project (Ticino, Switzerland)

NASA Astrophysics Data System (ADS)

Scapozza, Cristian; Bruder, Andreas; Domenici, Mattia; Lepori, Fabio; Pera, Sebastian; Pozzoni, Maurizio; Rioggi, Stefano; Colombo, Luca

2017-04-01

Mountain lakes and their catchments of the Alpine cryosphere are facing global pressures including climate warming and deposition of atmospheric pollutants. Due to their remoteness, often low buffer capacities and sensitive biotic communities, alpine lake catchments are particularly well suited as sentinels of environmental change. Lago Nero is the object of an intensive survey, aimed at developing predictive models of catchment-wide ecosystem responses to environmental change (Bruder et al. 2016). Lago Nero is located at the head of Val Bavona (Canton Ticino, southern Switzerland), in a southwest-facing catchment, with altitude ranging from 2385 to 2842 m asl. The substrate is dominated by gneissic bedrock with patches of grassy vegetation and shallow soils. The catchment is snow-covered approximately from November to May. For a similar period, the lake is ice-covered. Lago Nero is an oligotrophic, soft-water lake with a surface of approximatively 13 ha and a maximal depth of 73 m. According to the regional model of potential permafrost distribution in the southern Swiss Alps (Scapozza & Mari 2010), the presence of discontinuous permafrost is probable in almost the entire surface of the catchment covered by loose debris. A direct evidence of permafrost occurrence is the presence of a small active/inactive rock glacier in the south-eastern part of the catchment (front altitude: 2560 m asl). Monitoring of the site began in summer 2014, with an initial phase aimed at developing and testing methodologies and at evaluating the suitability of the catchment and the feasibility of the monitoring program. The intensive survey at Lago Nero measures a wide array of ecosystem responses, including runoff quantity and chemistry, catchment soil temperature (also on the rock glacier) and composition of terrestrial vegetation. Sampling frequency depends on the parameter measured, varying from nearly continuous (e.g. runoff and temperature) to five-year intervals (e.g. soil and

Electricity supply efficiency and organizational growth and profitability in Lagos, Nigeria

NASA Astrophysics Data System (ADS)

Adeleke, Adedeji Tajudeen

A modern and efficient infrastructure is a basic necessity for economic development and integration into the global economy. The specific problem was the inadequate and unreliable supply of electricity to manufacturing corporations in Lagos, Nigeria. The purpose of the current quantitative correlational research study was to examine if there was a correlation between electricity supply efficiency and organizational growth and profitability in manufacturing corporations in Lagos, Nigeria. The population of the current correlational research study involved 28 out of 34 manufacturing corporations from various industrial sectors in Lagos, Nigeria, that are listed and traded on the Nigerian Stock Exchange. Spearman rho correlations were used to assess the relationships between independent variables of electricity supply efficiency levels and the dependent variables of organizational growth and profitability. The result of the correlational analysis of the data revealed that there was a statistically significant, strong positive correlation between the Average Gross Income (1998-2007) and Average Actual Electricity supply efficiency level (1998-2007), rho = 0.57; p = 0.002. A statistically significant, strong positive correlation was found between the Average Balance Sheet Size (1998-2007) and Average Actual Electricity Supply Efficiency Level (1998-2007), rho = 0.54; p = 0.003. A statistically significant, strong positive correlation between the Average Profit After Tax (1998-2007) and Average Actual Electricity Supply Efficiency Level (1998-2007), rho = 0.60; p = 0.001, was found. No statistically significant correlation between the Average Return on Investment (1998-2007) and Average Actual Electricity supply efficiency level (1998-2007), rho = 0.19; p = 0.33, was discovered.

Motivations for Gang Membership in Lagos, Nigeria: Challenge and Resilience

ERIC Educational Resources Information Center

Salaam, Abeeb Olufemi

2011-01-01

The current study explores the major challenges (in the form of risk factors) that may influence unemployed youths' involvement in gang and criminal activity in Lagos, Nigeria. A combination of techniques (e.g., oral, in-depth interviews, and questionnaires) were used for the data collection. The computed outcomes establish some of the major…

An Analysis of Deaths Due to Tuberculosis at the Lagos University Teaching Hospital

PubMed Central

Bandele, E.O.; Olude, I.O.

1985-01-01

An analysis was made of deaths from tuberculosis in the Lagos University Teaching Hospital from 1976 to 1980. Of the 320 patients assessed, 240 were determined to have died from tuberculosis. Tuberculous meningitis was the main cause of death. Forty-two percent of the deaths occurred in the age group of 0 to 10 years old, and 47.5 percent of the patients died within one week of diagnosis. Potentially avoidable factors contributing to death include late reporting by patients to medical personnel, lack of bacillus of Calmette and Guerin (BCG) vaccine, irregular taking of medications by patients, and late referral of patients to specialized hospitals. There is a need for improved education of patients and medical personnel about the management of tuberculosis in Lagos. PMID:4046063

Dog Ecology and Population Studies in Lagos State, Nigeria

PubMed Central

Hambolu, Sunday E.; Dzikwi, Asabe A.; Kwaga, Jacob K.P.; Kazeem, Haruna M.; Umoh, Jarlath U.; Hambolu, Dupe A.

2014-01-01

Dog population dynamics have a major impact upon the effectiveness of rabies control strategies. As such, understanding domestic dog ecology has been recognized as central to the design of effective rabies control programmes. This study was conducted to determine the dog ecology in Lagos State using compound dog count and street dog count in the three senatorial districts (Lagos West, East and Central) of Lagos State from February, 2011 to January, 2012. A total of 546 questionnaires were distributed for the compound dog count and all were completed and returned. Various aspects of dog ecology were determined, including size, sex, breed of the dog population, management of dogs and rabies awareness among the respondents. Out of the 546 compounds surveyed, 518 (94.87%) owned at least one dog. A total of 1,427 dogs were counted from the street counts while a total of 1,447 dogs (2.8 dogs/compound) were counted from the compound count. The dogs comprised of 583 males and 864 females, out of which 64.10% are confined. The dog vaccination coverage in the dog population surveyed was 64.10% and administered majorly (91.30%) by veterinarians. Security (60%) and pets (26%) were the major reasons for keeping dogs. Majority (88.80%) of the respondents were aware of rabies and its mode of transmission, but still believed in the use of concoctions (40.40%), herbs (19.90%) and consumption of the organ of the offending dog (11.50%) for the treatment of rabies. The findings of this study showed a male: female ratio of dog to be 1:1.5 and a dog: human ratio of 1:5.6. There was also a responsible dog ownership as majority of the respondents do confine, vaccinate and provide food for their dogs. Vaccination coverage of the total dog population was however below the 70-80% target recommended by the World Health Organization to achieve herd immunity. PMID:24576383

Ecological health status of the Lagos wetland ecosystems: Implications for coastal risk reduction

NASA Astrophysics Data System (ADS)

Agboola, Julius I.; Ndimele, Prince E.; Odunuga, Shakirudeen; Akanni, Adeniran; Kosemani, Bosede; Ahove, Michael A.

2016-12-01

Lagos, a major urban agglomeration in the world is characterized by wetlands and basin for upstream rivers such as Ogun, Oshun and Yewa Rivers. Ongoing environmental pressures exerted by large-scale land reclamation for residential quarters, refuse and sewage dumping, and other uses, however, are suspected to have had a substantial impact on ecological health of the Lagos wetland ecosystems over the last few decades. To determine the impact of these pressures, we examined spatial changes in three wetlands areas- Badore/Langbasa (BL), Festac/Iba/Ijegun (FI) and Ologe/Otto-Awori (OO) through field sample collection and analyses of surface water, sediments, air-water interface gas fluxes and vegetations. Surface water conductivity, total suspended solids (TSS), alkalinity, chloride, biological oxygen demand (BOD), nitrate, phosphate and heavy metals (Zn, Cu, Fe, Na, Mn, Pb, Cd, K and Ni) exhibited relative spatial stability while other water quality parameters varied significantly (P < 0.05) across the wetland areas. Also, dissolved inorganic carbon (DIC) contributed to most of the total dissolved solids (TDS) since only DIC correlated significantly with TDS (r = 0.889; P = 0.05, n = 12) and TS (r = 0.891; P = 0.05, n = 12), suggesting a strong capacity for carbon sequestration and carbon sink across the wetland areas. None of the encountered vegetation species are in the vulnerable category of the International Union for Conservation of Nature (IUCN). There are indications of steady rise in greenhouse gas levels in Lagos since air CO2 value at BL have reached global threshold of 400 ppm with OO and FI closely approaching. We conclude that the Lagos wetland ecosystems, especially OO and FI still have some semblance of natural habitat. However, further destruction and unwise use of the resources could cause damage to physical, chemical, geological and biological processes in nature, which could result to grave socio-economic and cultural consequences to the local

Decision scenario analysis for addressing sediment accumulation in Lago Lucchetti, Puerto Rico

EPA Science Inventory

A Bayesian belief network (BBN) was used to characterize the effects of sediment accumulation on water storage capacity of a reservoir (Lago Lucchetti) in southwest Puerto Rico and the potential of different management options to increase reservoir life expectancy. Water and sedi...

Recovery and recycling practices in municipal solid waste management in Lagos, Nigeria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kofoworola, O.F.

The population of Lagos, the largest city in Nigeria, increased seven times from 1950 to 1980 with a current population of over 10 million inhabitants. The majority of the city's residents are poor. The residents make a heavy demand on resources and, at the same time, generate large quantities of solid waste. Approximately 4 million tonnes of municipal solid waste (MSW) is generated annually in the city, including approximately 0.5 million of untreated industrial waste. This is approximately 1.1 kg/cap/day. Efforts by the various waste management agencies set up by the state government to keep its streets and neighborhoods cleanmore » have achieved only minimal success. This is because more than half of these wastes are left uncollected from the streets and the various locations due to the inadequacy and inefficiency of the waste management system. Whilst the benefits of proper solid waste management (SWM), such as increased revenues for municipal bodies, higher productivity rate, improved sanitation standards and better health conditions, cannot be overemphasized, it is important that there is a reduction in the quantity of recoverable materials in residential and commercial waste streams to minimize the problem of MSW disposal. This paper examines the status of recovery and recycling in current waste management practice in Lagos, Nigeria. Existing recovery and recycling patterns, recovery and recycling technologies, approaches to materials recycling, and the types of materials recovered from MSW are reviewed. Based on these, strategies for improving recovery and recycling practices in the management of MSW in Lagos, Nigeria are suggested.« less

Pattern and outcome of cases seen at the Adult Accident and Emergency Department of the Lagos University Teaching Hospital, Idi-Araba, Lagos.

PubMed

Uzoechina, N S; Abiola, A O; Akodu, B A; Mbakwem, A; Arogundade, A R; Tijani, H; Adegbesan-Omilabu, M A

2012-01-01

The accident and emergency department constitutes one of the vital entry points of patients into the healthcare facility of the hospital the world over. It responds to and manages variety of cases in all the clinical areas and thus pr vides an insight to the quality of care available in the health institution. The aim of this study is to determine the pattern of cases seen as well as the causes of deaths at the adult accident and emergency department of the Lagos UniversityTeaching Hospital, Idi-Araba, Lagos. Retrospective review of records of all patients attended to at the adult accident and emergency department of the Lagos University Teaching Hospital in 2009 and 2010 was carried out. Data spread sheet was used to collect data on demographic indices, diagnosis, outcome, date admitted, date discharged and amount paid from casualty attendance register and Nurses' report books. Data was collated and analysed using Epi-Info version 3.4.1 statistical software package. Out of the 5,427 available patients' records reviewed, 4,761(87.7%) were recorded as "discharged alive", 546 (10.1%) were recorded as "died", while 120 (2.2%) were recorded as "brought in dead". Of those discharged alive, male attendance was 2,376 (49.10%) while that of the female was 2,385 (50.10%). Majority of these patients were aged 20-39 years and the mean age of the patients was 39.96 +/- 18.22 yrs. Majority of cases seen were medical in origin (53.7%) and highest medical case seen was cerebrovascular accident, Commonest cause of death was from medical cases [69.2%] (cerebrovascular accident 22.0%). Male mortality was 55.3% while female mortality was 44.7%, mean age was 46.86 +/- 17.61. Most affected age group was 40 - 59 years (35.4%) and highest number of death was seen in December. The commonest case seen as well as commonest cause of death was cerebrovascular accident. A high number of heart failure, head injuries, road traffic accidents, upper gastrointestinal bleeding and post partum

Profile of medical waste management in two healthcare facilities in Lagos, Nigeria: a case study.

PubMed

Idowu, Ibijoke; Alo, Babajide; Atherton, William; Al Khaddar, Rafid

2013-05-01

Proper management and safe disposal of medical waste (MW) is vital in the reduction of infection or illness through contact with discarded material and in the prevention of environmental contamination in hospital facilities. The management practices for MW in selected healthcare facilities in Lagos, Nigeria were assessed. The cross-sectional study involved the use of questionnaires, in-depth interviews, focused group discussions and participant observation strategies. It also involved the collection, segregation, identification and weighing of waste types from wards and units in the representative facilities in Lagos, Nigeria, for qualitative and quantitative analysis of the MW streams. The findings indicated that the selected Nigerian healthcare facilities were lacking in the adoption of sound MW management (MWM) practices. The average MW ranged from 0.01 kg/bed/day to 3.98 kg/bed/day. Moreover, about 30% of the domestic waste from the healthcare facilities consisted of MW due to inappropriate co-disposal practices. Multiple linear regression was applied to predict the volume of waste generated giving a correlation coefficient (R(2)) value of 0.99 confirming a good fit of the data. This study revealed that the current MWM practices and strategies in Lagos are weak, and suggests an urgent need for review to achieve vital reversals in the current trends.

Anti-malarial drug quality in Lagos and Accra - a comparison of various quality assessments

PubMed Central

2010-01-01

Background Two major cities in West Africa, Accra, the capital of Ghana, and Lagos, the largest city of Nigeria, have significant problems with substandard pharmaceuticals. Both have actively combated the problem in recent years, particularly by screening products on the market using the Global Pharma Health Fund e.V. Minilab® protocol. Random sampling of medicines from the two cities at least twice over the past 30 months allows a tentative assessment of whether improvements in drug quality have occurred. Since intelligence provided by investigators indicates that some counterfeit producers may be adapting products to pass Minilab tests, the results are compared with those from a Raman spectrometer and discrepancies are discussed. Methods Between mid-2007 and early-2010, samples of anti-malarial drugs were bought covertly from pharmacies in Lagos on three different occasions (October 2007, December 2008, February 2010), and from pharmacies in Accra on two different occasions (October 2007, February 2010). All samples were tested using the Minilab® protocol, which includes disintegration and active ingredient assays as well as visual inspection, and most samples were also tested by Raman spectrometry. Results In Lagos, the failure rate in the 2010 sampling fell to 29% of the 2007 finding using the Minilab® protocol, 53% using Raman spectrometry, and 46% using visual inspection. In Accra, the failure rate in the 2010 sampling fell to 54% of the 2007 finding using the Minilab® protocol, 72% using Raman spectrometry, and 90% using visual inspection. Conclusions The evidence presented shows that drug quality is probably improving in both cities, especially Lagos, since major reductions of failure rates over time occur with all means of assessment. Many more samples failed when examined by Raman spectrometry than by Minilab® protocol. The discrepancy is most likely caused by the two techniques measuring different aspects of the medication and hence the discrepancy

Sedimentation survey of Lago Loco, Puerto Rico, March 2000

USGS Publications Warehouse

Soler-López, Luis R.

2002-01-01

Lago Loco, a small reservoir property of the Puerto Rico Electric Power Authority and part of the Southwestern Puerto Rico Project, has lost 64 percent of its original storage capacity. In 1951, the original storage capacity was about 2.40 million cubic meters, decreasing to 1.43 million cubic meters in 1986 and to 0.87 million cubic meters in March 2000. The storage loss or longterm sedimentation rate increased from 27,714 cubic meters per year from the period of 1951 to 1986 to 31,224 cubic meters per year for the period of 1951 to 2000. This represents a capacity loss of about 1.1 percent per year for the period of 1951 to 1986 and 1.3 percent per year for 1951 to 2000. The trapping efficiency of the reservoir was about 92 percent in 1951, decreasing to about 87 percent in 1986, and to about 80 percent in March 2000. The sediment yield of the net sediment- contributing drainage area increased from 1,504 megagrams per square kilometer per year between 1951 and 1986 to 1,774 megagrams per square kilometer per year between 1951 and 2000, or about 18 percent. At the current sedimentation rate of the reservoir, the life expectancy of Lago Loco is about 28 more years or until the year 2028.

Age and extent of the Ilopango TBJ Tephra inferred from a Holocene chronostratigraphic reference section, Lago De Yojoa, Honduras

USGS Publications Warehouse

Mehringer, P.J.; Sarna-Wojcicki, A. M.; Wollwage, L.K.; Sheets, P.

2005-01-01

Eruption of central El Salvador's Ilopango Volcano early in the first millennium A.D. caused death, cultural devastation, and exodus of southern Mesoamericans. It also left a time-stratigraphic marker in western El Salvador and adjacent Guatemala - the Ilopango Tierra Blanca Joven, or TBJ tephra. Mineral suites and major element abundances identify a silicic volcanic ash in cores from Lago de Yojoa, Honduras, as Ilopango TBJ. This extends its reported range more than 150 km to the northeast. Analyses of glass from the TBJ tephra from the Chalchuapa archaeological site, El Salvador, and from Lago de Yojoa, Honduras, establish the first major element reference fingerprint for the TBJ tephra. The Lago de Yojoa cores also hold two previously undated trachyandesitic tephra layers originating from the nearby Lake Yojoa Volcanic Field. One fell shortly before 11,000 14C yr B.P. and the other about 8600 14C yr B.P. ?? 2004 University of Washington. All rights reserved.

Knowledge, attitude and practice towards child adoption amongst women attending infertility clinics in Lagos State, Nigeria

PubMed Central

Kofoworola, Odeyemi

2011-01-01

Abstract Background Child adoption is a recommended alternative form of infertility management. Infertility is of public health importance in Nigeria and many other developing nations. This is a result of its high prevalence and especially because of its serious social implications as the African society places a passionate premium on procreation in any family setting. Objectives The aim of this study was to determine the knowledge, attitude and practice of child adoption amongst women attending infertility clinics in teaching hospitals in Lagos State and to determine the factors that influence their attitude and practice towards it. Method A cross-sectional descriptive design was used. Data were collected by using a structured questionnaire which was interviewer-administered. The study was conducted in the two teaching hospitals in Lagos State (LUTH [Lagos University Teaching Hospital] and LASUTH [Lagos State University Teaching Hospital]) from amongst 350 women attending the gynaecological clinics. All the patients under management for infertility at the gynaecology clinics during the period of the study were interviewed. Results Many respondents (85.7%) had heard of child adoption and 59.3% of them knew the correct meaning of the term. More than half of the respondents (68.3%) said that they could love an adopted child but less than half of them (33.7%) were willing to consider adoption. Only 13.9% has ever adopted a child. The major reason given for their unwillingness to adopt was their desire to have their own biological child. Factors that were favourable towards child adoption were Igbo tribe identity, an age above 40 years, duration of infertility above 15 years, and knowing the correct meaning of child adoption. Conclusion There is a poor attitude to adoption even amongst infertile couples. Interventions need to be implemented to educate the public on child adoption, to improve their attitude towards adoption and to make it more acceptable.

Dam failure analysis for the Lago de Matrullas Dam, Orocovis, Puerto Rico

USGS Publications Warehouse

Torres-Sierra, Heriberto; Gómez-Fragoso, Julieta

2015-01-01

Results from the simulated dam failure of the Lago de Matrullas Dam using the HEC–RAS model for the 6- and 24-hour PMP events showed peak discharges at the dam of 3,149.33 and 3,604.70 m3/s, respectively. Dam failure during the 100-year-recurrence, 24-hour rainfall event resulted in a peak discharge of 2,103.12 m3/s directly downstream from the dam. Dam failure under sunny day conditions produced a peak discharge of 1,695.91 m3/s at the dam assuming the antecedent lake level was at the morning-glory spillway invert elevation. Flood-inundation maps prepared as part of the study depict the flood extent and provide valuable information for preparing an Emergency Action Plan. Results of the failure analysis indicate that a failure of the Lago de Matrullas Dam could cause flooding to many of the inhabited areas along stream banks from the Lago de Matrullas Dam to the mouth of the Río Grande de Manatí. Among the areas most affected are the low-lying regions in the vicinity of the towns of Ciales, Manatí, and Barceloneta. The delineation of the flood boundaries near the town of Barceloneta considered the effects of a levee constructed during 2000 at Barceloneta in the flood plain of the Río Grande de Manatí to provide protection against flooding to the near-by low-lying populated areas. The results showed overtopping can be expected in the aforementioned levee during 6- and 24-hour probable-maximum-precipitation dam failure scenarios. No overtopping of the levee was simulated, however, during dam failure scenarios under the 100-year recurrence, 24-hour rainfall event or sunny day conditions.

Iron deficiency anaemia among apparently healthy pre-school children in Lagos, Nigeria.

PubMed

Akodu, Olufemi S; Disu, Elizabeth A; Njokanma, Olisamedua F; Kehinde, Omolara A

2016-03-01

Iron deficiency, and specifically iron deficiency anaemia, remains one of the most severe and important nutritional deficiencies in the world today. To estimate the prevalence and associated factors for iron deficiency anaemia among pre-school children in Lagos. The study was conducted from December 2009 to February 2010 at the outpatient clinics of Lagos State University Teaching Hospital, Lagos. Serum iron, total iron binding capacity, transferrin saturation and serum ferritin were assayed in subjects. The primary outcome measured was iron deficiency anaemia established based on the following criteria: hemoglobin <11.0 g/dl1 plus 2 or more of the following: MCV <70fl, transferrin saturation <10% or serum ferritin <15ng/dL. Statistical analysis included Pearson Chi square analysis and logistic regression analysis. A total of 87 apparently healthy subjects were recruited. Only one subject had iron depletion and this child belonged to the ≤ 2 years age category. None of the recruited subjects had iron deficiency without anaemia. Nine of the study subjects (10.11%) had iron deficiency anaemia. The prevalence of iron deficiency anaemia was significantly higher among younger age group than in the older age group (19.1% Vs 2.1%, p = 0.022). The prevalence of iron deficiency anaemia was significantly higher among subjects with weight-for-age, and weight-for-height Z scores below two standard scores (83.3% and 75.0% respectively, p = <0.001 and 0.001 respectively). The overall prevalence of iron deficiency anaemia among study subjects was 10.11%. Iron deficiency anaemia was more common in children aged two years and below. Weight-for-age and weight-for-height Z scores below minus two standard scores were strongly associated with iron deficiency anaemia.

Estimating sectoral pollution load in Lagos by Industrial Pollution Projection System (IPPS).

PubMed

Oketola, A A; Osibanjo, O

2007-05-15

Sensitivity to environmental issues brought about increasing pressure from local community, groups, environmental organizations and government regulators on industries to reduce their pollutant emissions. In this study, Industrial Pollution Projection System (IPPS), which was developed by the Infrastructure and Environment Team of the World Bank, was used to estimate pollution load in ton/yr (with respect to employment) of industrial sectors in Lagos. The IPPS was developed to exploit the fact that the scale of industrial activity, its sectorial composition, and the process technologies, employed in production, heavily affect industrial pollution. Available data, from Manufacturer's Association of Nigeria (M.A.N.) for the years 1997-2002 was used for the estimation. From the cumulative ranking of the pollution load (ton/yr) estimate to all media (i.e. air, land, and water), Chemical and Pharmaceutical (CPH) sector is the highest polluting sector, followed by Basic Metal (BML), Domestic and Industrial Plastics (DIP), and Food, Beverage and Tobacco (FBT) sectors. Some of these sectors have the highest number of employees, and also appeared as the most polluting sectors in Lagos.

Reprint of Ecological health status of the Lagos wetland ecosystems: Implications for coastal risk reduction

NASA Astrophysics Data System (ADS)

Agboola, Julius I.; Ndimele, Prince E.; Odunuga, Shakirudeen; Akanni, Adeniran; Kosemani, Bosede; Ahove, Michael A.

2016-12-01

Lagos, a major urban agglomeration in the world is characterized by wetlands and basin for upstream rivers such as Ogun, Oshun and Yewa Rivers. Ongoing environmental pressures exerted by large-scale land reclamation for residential quarters, refuse and sewage dumping, and other uses, however, are suspected to have had a substantial impact on ecological health of the Lagos wetland ecosystems over the last few decades. To determine the impact of these pressures, we examined spatial changes in three wetlands areas- Badore/Langbasa (BL), Festac/Iba/Ijegun (FI) and Ologe/Otto-Awori (OO) through field sample collection and analyses of surface water, sediments, air-water interface gas fluxes and vegetations. Surface water conductivity, total suspended solids (TSS), alkalinity, chloride, biological oxygen demand (BOD), nitrate, phosphate and heavy metals (Zn, Cu, Fe, Na, Mn, Pb, Cd, K and Ni) exhibited relative spatial stability while other water quality parameters varied significantly (P < 0.05) across the wetland areas. Also, dissolved inorganic carbon (DIC) contributed to most of the total dissolved solids (TDS) since only DIC correlated significantly with TDS (r = 0.889; P = 0.05, n = 12) and TS (r = 0.891; P = 0.05, n = 12), suggesting a strong capacity for carbon sequestration and carbon sink across the wetland areas. None of the encountered vegetation species are in the vulnerable category of the International Union for Conservation of Nature (IUCN). There are indications of steady rise in greenhouse gas levels in Lagos since air CO2 value at BL have reached global threshold of 400 ppm with OO and FI closely approaching. We conclude that the Lagos wetland ecosystems, especially OO and FI still have some semblance of natural habitat. However, further destruction and unwise use of the resources could cause damage to physical, chemical, geological and biological processes in nature, which could result to grave socio-economic and cultural consequences to the local

A workshop on medical ethics at the College of Medicine, Lagos University.

PubMed

Olukoya, A A

1984-12-01

As part of an effort to improve the teaching of medical ethics in the College of Medicine, Lagos University two-day workshops were organised. Participants included people from various walks of life, for example politicians, lawyers, doctors, and patients. The workshops were quite successful, and have led to more extensive teaching of medical ethics in the college.

Hepatic pathologies in the brackish water catfish (Chrysichthys nigrodigitatus) from contaminated locations of the Lagos lagoon complex

USGS Publications Warehouse

Olarinmoye, O.; Taiwo, V.; Clarke, E.; Kumolu-Johnson, C.; Aderinola, O.; Adekunbi, F.

2010-01-01

Several toxicological studies into the effects of aquatic pollutants on the liver of teleost fish exist in literature. The focus on the liver in these studies is predicated on its central nature in the scheme of biotransformation and excretion of xenobiotics following exposure in polluted water bodies. As a consequence of the latter primary role of the liver in these processes it is regarded as a predilective site for the sub lethal effects of xenobiotics on the organism usually detectable at histological level. Hepatic histopathology recorded in livers from feral populations of the brackish water catfish Chrysichthys nigrodigitatus from locations on the Lagos lagoon complex with significant anthropogenic inputs from denizen populations and industries are presented. Liver sections from sixty specimens from two locations on the Lagos lagoon complex (Badagry lagoon: 6??24'N, 2??56'E; and Lagos lagoon: 6??29'N, 3??22'E) were analysed. Observed pathologies included hydropic degeneration (58%), portal / sinusoidal congestion (33%), hepatic necrosis (26%), hemosiderosis (12%) and foci of cellular alterations (FCA's). No obvious oncologic features were observed; the presence of the hydropic Vacuolation lesion was taken as prelude to the development of neoplasms and discussed as such. ?? 2009, Penkala Bt., Budapest, Hungary.

The knowledge, perceptions and practice of pharmacovigilance amongst community pharmacists in Lagos state, south west Nigeria.

PubMed

Oreagba, I A; Ogunleye, O J; Olayemi, S O

2011-01-01

Community Pharmacists both have an important responsibility in monitoring the ongoing safety of medicines and are widely accessible to do it. This study aims to investigate the knowledge, perceptions and practice of Pharmacovigilance amongst community pharmacists in Lagos State, South West Nigeria A cross-sectional observational survey was used in this study. A multistage random sampling technique was employed in the selection of 420 community pharmacies in Lagos. About 55% of respondents have ever heard of the word 'Pharmacovigilance' out of which less than half (representing only 18% of all respondents) could define the term 'Pharmacovigilance'. Forty percent of the respondents stated that patients reported ADRs to them at least once a month, and 20% reported to the relevant authorities. However only 3% of respondents actually reported an ADR to the National Pharmacovigilance Centre. The most important reason for poor reporting was lack of knowledge about how to report ADRs (44.6%).Meanwhile, 90% of respondents believed that the role of the pharmacists in ADR reporting was important. Most community pharmacists were willing to practice pharmacovigilance if they were trained. Community pharmacists in Lagos had poor knowledge about pharmacovigilance. Reporting rate was also poor. There is an urgent need for educational programs to train pharmacists about pharmacovigilance and ADR reporting. Copyright © 2010 John Wiley & Sons, Ltd.

Phylogeny of Lagos bat virus: challenges for lyssavirus taxonomy.

PubMed

Markotter, W; Kuzmin, I; Rupprecht, C E; Nel, L H

2008-07-01

Lagos bat virus (LBV) belongs to genotype 2 of the Lyssavirus genus. The complete nucleoprotein (N), phosphoprotein (P), matrixprotein (M) and glycoprotein (G) genes of 13 LBV isolates were sequenced and phylogenetically compared with other lyssavirus representatives. The results identified three different lineages of LBV. One of these lineages demonstrated sufficient sequence diversity to be considered a new lyssavirus genotype (Dakar bat lyssavirus). The suggested quantitative separation of lyssavirus genotypes using the N, P, M and G genes was also investigated using P-distances matrixes. Results indicated that the current criteria should be revised since overlaps between intergenotypic and intragenotypic variation occur.

Use of Remote Sensing and Local Knowledge for Geoconservation of Regiao dos Lagos, Brazil

NASA Astrophysics Data System (ADS)

Avelar, S.; Vasconcelos, G.; Mansur, K. L.; Anjos, S. C.

2013-12-01

A series of lagoons can be found along the coastline of Rio de Janeiro, in the so-called Regiao dos Lagos. The lagoons differ in size, physicochemical, sedimentological and biological characteristics. Rare examples of litifying microbialites that produce stromatolites, the oldest fossils on Earth, can be found living in this lagoon system. The occurrence of stromatolites in the region is of great scientific interest because it enables the study of possible analogues of the earliest life on Earth. However, this region has been suffering from intense human activities and degradations. Geoconservation planning requires an assessment of the characteristics of the region and its potential threats. The primary goal of this study is to assess physical environmental changes and anthropogenic impacts over the last four decades in Regiao dos Lagos. Using a broad integrative assessment combining remote sensing, GIS, field studies and local knowledge of communities, land-cover and land-use classes were identified, as well as the main human activities impacting the environment. The seasonal and weekend tourism and urban sprawl in this coastal area of Rio de Janeiro triggers the occupation of new areas and the removal of natural vegetation, especially on lagoon margins. This disorderly occupation by an ever increasing population, with both legal and illegal constructions and the subsequent overload of the local infrastructure, e.g. increase of electrical energy consumption, volume of vehicles, pollution in air, water and soil and problems with water supply and wastewater treatment, are hastening the gradual degradation of the lake ecosystem. The main driving forces to environmental changes over the last four decades in Regiao dos Lagos were the change of dense vegetation, saline and bare soil classes into built-up areas, adding to the poor waste treatment and inadequate sewage disposal. This analysis provides a basis for a better control of anthropogenic impacts and

Psycho-Demographic Correlates of Behaviour towards Seeking Counselling Intervention among Workers in Lagos, Nigeria

ERIC Educational Resources Information Center

Gesinde, Abiodun Matthew; Sanu, Oluwafunto Jolade

2015-01-01

This study sought to examine the impact which age, gender and psychological adjustment have on behaviour towards seeking professional counselling intervention. Multistage sampling technique was employed to select a total of three hundred workers across Lagos metropolis. The ex post facto research design was adopted for the study. Inventory of…

Perceptions and Concerns about Inclusive Education among Students with Visual Impairments in Lagos, Nigeria

ERIC Educational Resources Information Center

Brydges, Colton; Mkandawire, Paul

2017-01-01

This article examines the perceptions of inclusive education in Lagos, Nigeria, based upon in-depth interviews conducted with students with visual impairments during the month of July 2013. The results and discussions are situated within critical disability theory. Despite decades of inclusive education policies, the findings of the study show…

Asymptomatic bacteriuria among antenatal women in Lagos.

PubMed

Olamijulo, Joseph Ayodeji; Adewale, Chris Olu; Olaleye, Olalekan

2016-08-01

This cross-sectional study was undertaken to determine the prevalence of asymptomatic bacteriuria (ASB), the commonest bacterial isolates and the antibiotic sensitivity pattern among 556 pregnant women in Lagos University Teaching Hospital (LUTH), Nigeria. Women with a bacterial count over 100,000 colony-forming units per millilitre of the same organisms in paired urine samples were considered to have ASB. The prevalence of ASB was 14.6%. Klebsiella was the commonest micro-organism (39.2%) isolated. ASB was significantly associated with marital status, body mass index and parity. There was a significant relationship between urinary nitrites and ASB. The isolated organisms showed remarkable resistance to commonly prescribed antibiotics such as amoxicillin, cloxacillin and trimethoprim but good sensitivity to ofloxacin, gentamycin and ceftazidime. These facts have implications for the management of ASB in pregnancy.

Levels of Job Satisfaction and Performance of Sports Officers in Lagos State Secondary Schools

ERIC Educational Resources Information Center

Onifade, Ademola; Keinde, Idou; Kehinde, Eunice

2009-01-01

The purpose of this paper was to examine the relationship between job satisfaction levels of sports officers and sports performance of secondary schools in Lagos State. Data were collected from 200 subjects across 10 Local Education Districts. Job Descriptive Index was used to determine job satisfaction while performance in the Principals' Soccer…

Oral health care knowledge and practices of a group of deaf adolescents in Lagos, Nigeria.

PubMed

Oredugba, Folakemi A

2004-01-01

This study sought to determine the oral health care knowledge and practices of a group of deaf adolescents in Lagos. The study involved 50 students of Wesley School 1 for the Deaf, Lagos (26 males and 24 females, aged 10-19 years, mean 13.3 +/- 2.8). Information about previous dental care, oral hygiene, and snacking habits were obtained through a questionnaire and sign language by the teachers. Only 12 percent of pupils had received dental care. Eight percent and 72 percent, respectively, gave correct answers to causes of tooth decay and bleeding gums. Ninety-four percent brushed their teeth once daily, with no significant sex difference (P > .05). Reported dental problems include bleeding gums (36%), tooth discoloration, and tooth decay. The majority of pupils (60%) preferred biscuits and soft drinks as snacks. More than 90 percent were willing to have a dental check-up. The oral health knowledge and practices of this group of children will improve through a controlled school-based oral health education program.

Climate change in Lagos state, Nigeria: what really changed?

PubMed

Sojobi, Adebayo Olatunbosun; Balogun, Isaac Idowu; Salami, Adebayo Wahab

2015-10-01

Our study revealed periodicities of 2.3 and 2.25 years in wet and dry seasons and periodicities of 2 to 5 years on seasonal and annual timescales. Minimum temperature (Tmin), maximum temperature (Tmax) and evaporation recorded increases of 2.47, 1.37 and 28.37 %, respectively, but a reduction of 19.58 % in rainfall on decadal timescale. Periodicity of 8 to 12 years was also observed in annual Tmax. Cramer's test indicated a warming trend with significant Tmax increase in February, April, July, August, October and November during 2000-2009 on decadal monthly timescale, a significant decline in Summer rainfall but significant Tmax increase in Spring, Autumn and Winter on decadal seasonal timescale. The low correlation of rainfall with temperature parameters and evaporation indicates that advection of moisture into Lagos State seems to be the dominant mechanism controlling rainfall within the State alongside other tropical and extra-tropical factors. In addition, our study revealed that the persistent state of minimum temperature often precedes the arrival and reversal of the phase of maximum temperature. Furthermore, our study also revealed that extreme and high variable rainfalls, which are associated with the increased warming trend, had periodicities of 1 to 3 years with a probability of 86.45 % of occurring every 3 years between April and September. It is recommended that government and private sector should give financial and technical supports to climate researches in order to appropriately inform policy making to improve the adaptive capacity and resilience of Lagos State against climate change impacts and guard against maladaptation.

Multi-stakeholder perspectives on access, availability and utilization of emergency obstetric care services in Lagos, Nigeria: A mixed-methods study

PubMed Central

Wright, Kikelomo; Sonoiki, Olatunji; Ilozumba, Onaedo; Ajayi, Babatunde; Okikiolu, Olawunmi; Akinola, Oluwarotimi

2017-01-01

Globally, Nigeria is the second most unsafe country to be pregnant, with Lagos, its economic nerve center having disproportionately higher maternal deaths than the national average. Emergency obstetric care (EmOC) is effective in reducing pregnancyrelated morbidities and mortalities. This mixed-methods study quantitatively assessed women’s satisfaction with EmOC received and qualitatively engaged multiple key stakeholders to better understand issues around EmOC access, availability and utilization in Lagos. Qualitative interviews revealed that regarding access, while government opined that EmOC facilities have been strategically built across Lagos, women flagged issues with difficulty in access, compounded by perceived high EmOC cost. For availability, though health workers were judged competent, they appeared insufficient, overworked and felt poorly remunerated. Infrastructure was considered inadequate and paucity of blood and blood products remained commonplace. Although pregnant women positively rated the clinical aspects of care, as confirmed by the survey, satisfaction gaps remained in the areas of service delivery, care organization and responsiveness. These areas of discordance offer insight to opportunities for improvements, which would ensure that every woman can access and use quality EmOC that is sufficiently available. PMID:29456825

Holocene glacier history of the Lago Argentino basin, Southern Patagonian Icefield

NASA Astrophysics Data System (ADS)

Strelin, Jorge A.; Kaplan, Michael R.; Vandergoes, Marcus J.; Denton, George H.; Schaefer, Joerg M.

2014-10-01

We present new geomorphic, stratigraphic, and chronologic data for Holocene glacier fluctuations in the Lago Argentino basin on the eastern side of the southern Patagonian Andes. Chronologic control is based on 14C and surface-exposure 10Be dating. After the Lateglacial maximum at 13,000 cal yrs BP, the large ice lobes that filled the eastern reaches of Lago Argentino retreated and separated into individual outlet glaciers; this recession was interrupted only by a stillstand or minor readvance at 12,200 cal yrs BP. The eight largest of these individual outlet glaciers are, from north to south: Upsala, Agassiz, Onelli, Spegazzini, Mayo, Ameghino, Perito Moreno, and Grande (formerly Frías). Holocene recession of Upsala Glacier exposed Brazo Cristina more than 10,115 ± 100 cal yrs BP, and reached inboard of the Holocene moraines in Agassiz Este Valley by 9205 ± 85 cal yrs BP; ice remained in an inboard position until 7730 ± 50 cal yrs BP. Several subsequent glacier readvances are well documented for the Upsala and Frías glaciers. The Upsala Glacier readvanced at least seven times, the first being a relatively minor expansion - documented only in stratigraphic sections - between 7730 ± 50 and 7210 ± 45 cal yrs BP. The most extensive Holocene advances of Upsala Glacier resulted in the deposition of the Pearson 1 moraines and related landforms, which are divided into three systems. The Pearson 1a advance occurred about 6000-5000 cal yrs BP and was followed by the slightly less-extensive Pearson 1b and 1c advances dated to 2500-2000 and 1500-1100 cal yrs BP, respectively. Subsequent advances of Upsala Glacier resulted in deposition of the Pearson 2 moraines and corresponding landforms, also separated into three systems, Pearson 2a, 2b, and 2c, constructed respectively at ˜700, >400, and <300 cal yrs BP to the early 20th century. Similar advances are also recorded by moraine systems in front of Grande Glacier and herein separated into the Frías 1 and Frías 2a, 2b

Isolation of Lagos bat virus from water mongoose.

PubMed

Markotter, Wanda; Kuzmin, Ivan; Rupprecht, Charles E; Randles, Jenny; Sabeta, Claude T; Wandeler, Alexander I; Nel, Louis H

2006-12-01

A genotype 2 lyssavirus, Lagos bat virus (LBV), was isolated from a terrestrial wildlife species (water mongoose) in August 2004 in the Durban area of the KwaZulu-Natal Province of South Africa. The virus isolate was confirmed as LBV by antigenic and genetic characterization, and the mongoose was identified as Atilax paludinosus by mitochondrial cytochrome b sequence analysis. Phylogenetic analysis demonstrated sequence homology with previous LBV isolates from South African bats. Studies performed in mice indicated that the peripheral pathogenicity of LBV had been underestimated in previous studies. Surveillance strategies for LBV in Africa must be improved to better understand the epidemiology of this virus and to make informed decisions on future vaccine strategies because evidence is insufficent that current rabies vaccines provide protection against LBV.

Sedimentation survey of Lago La Plata, Toa Alta, Puerto Rico, March–April 2015

USGS Publications Warehouse

Gómez-Fragoso, Julieta

2016-10-31

IntroductionLago La Plata is operated by the Puerto Rico Aqueduct and Sewer Authority (PRASA) and is part of the San Juan Metropolitan Water District. The reservoir serves a population of about 425,000 people. During 2013 the reservoir provided 0.307 million cubic meters (Mm3 ) of water per day (about 81 million gallons per day), which is equivalent to 31 percent of the total water demand for the metropolitan area (Wanda L. Molina, U.S. Geological Survey, written commun., 2015). The dam was constructed in 1974 and is located about 5 kilometers (km) south of the town of Toa Alta and 5 km north of the town of Naranjito (fig. 1). The drainage area upstream from the Lago La Plata dam is about 469 square kilometers (km2 ). The storage capacity at construction in 1974 was 26.84 Mm3 with a spillway elevation of 47.12 meters (m) above mean sea level (msl). Storage capacity was increased to 40.21 Mm3 in 1989 after the installation of bascule gates to provide a normal dam pool elevation at 52 m above msl (Puerto Rico Electric and Power Authority, 1979). The maximum height of the dam is about 40 m above the river bottom near the dam, and the intake structure consists of six 1.82-m-diameter ports facing upstream, with 6-m vertical spacing that begins at an elevation of 19 m above msl. The U.S. Geological Survey (USGS), in cooperation with the PRASA, conducted a bathymetric survey of the Lago La Plata reservoir during March and April 2015. The hydrographic survey was designed to provide an update of the reservoir storage capacity and sedimentation rate. Areas with substantial sediment accumulation are also discussed in this report. The results of the survey were used to prepare a bathymetric map showing the reservoir bottom (fig. 2) referenced with respect to the spillway elevation. This report also includes a summary of a previous bathymetric survey conducted in 2006 (Soler-López, 2008).

An Epidemiological Comparison of Parasitic Infection among Preschool Children in Four Areas in Lagos, Nigeria.

ERIC Educational Resources Information Center

Abidoye, R. O.

1995-01-01

Examined incidence of parasitic infections in school children in four contrasting areas of Lagos, Nigeria. Found that almost 40% of the infections identified were of the low socioeconomic status children. The 20 children from the higher socioeconomic status area, with the highest environmental sanitation, were without parasites. Twelve percent of…

Sedimentation survey of Lago Loíza, Trujillo Alto, Puerto Rico, July 2009

USGS Publications Warehouse

Soler-López, Luis R.; Licha-Soler, N.A.

2014-01-01

Lago Loíza is a reservoir formed at the confluence of Río Gurabo and Río Grande de Loíza in the municipality of Trujillo Alto in central Puerto Rico, about 10 kilometers (km) north of the town of Caguas, about 9 km northwest of Gurabo, and about 3 km south of Trujillo Alto (fig. 1). The Carraizo Dam is owned and operated by the Puerto Rico Aqueduct and Sewer Authority (PRASA), and was constructed in 1953 as a water-supply reservoir for the San Juan Metropolitan area. The dam is a concrete gravity structure that is located in a shallow valley and has a gently sloping left abutment and steep right abutment. Non-overflow sections flank the spillway section. Waterways include an intake structure for the pumping station and power plant, sluiceways, a trash sluice, and a spillway. The reservoir was built to provide a storage capacity of 26.8 million cubic meters (Mm3) of water at the maximum pool elevation of 41.14 meters (m) above mean sea level (msl) for the Sergio Cuevas Filtration Plant that serves the San Juan metropolitan area. The reservoir has a drainage area of 538 square kilometers (km2) and receives an annual mean rainfall that ranges from 1,600 to 5,000 millimeters per year (mm/yr). The principal streams that drain into Lago Loíza are the Río Grande de Loíza, Río Gurabo, and Río Cañas. Two other rivers, the Río Bairoa and Río Cagüitas, discharge into the Río Grande de Loíza just before it enters the reservoir. The combined mean annual runoff of the Río Grande de Loíza and the Río Gurabo for the 1960–2009 period of record is 323 Mm3. Flow from these streams constitutes about 89 percent of the total mean annual inflow of 364 Mm3 to the reservoir (U.S. Geological Survey, 2009). Detailed information about Lago Loíza reservoir structures, historical sediment accumulation, and a dredge conducted in 1999 are available in Soler-López and Gómez-Gómez (2005). During July 8–15, 2009, the U.S. Geological Survey (USGS) Caribbean Water Science

Sedimentation Survey of Lago Patillas, Puerto Rico, March 2007

USGS Publications Warehouse

Soler-López, Luis R.

2010-01-01

Lago Patillas is a reservoir located on the confluence of Rio Grande de Patillas and Rio Marin, in the municipality of Patillas in southern Puerto Rico, about 3 kilometers north of the town of Patillas and about 8 kilometers northeast of the town of Arroyo (fig. 1). The dam is owned and operated by the Puerto Rico Electric Power Authority (PREPA) and was constructed in 1914 for the irrigation of croplands in the southern coastal plains of Puerto Rico along the towns of Arroyo, Guayama, Patillas, and Salinas. Irrigation releases are made through the outlet works into the Patillas Irrigation Canal that extends 32.2 kilometers from the Patillas dam to Rio Salinas. The dam is a semi-hydraulic earthfill with a structural height of 44.80 meters, a top width of 4.57 meters, a base width of 190.49 meters, and a crest length of 325.21 meters. The spillway structure is physically separated from the earthfill dam, has an elevation of 58.21 meters above mean sea level, and has three radial arm gates (Puerto Rico Electric Power Authority, 1979). The reservoir impounds the waters of the Rio Grande de Patillas and Rio Marin. The reservoir has a drainage area of 66.3 square kilometers. Additional information and operational procedures are listed in Soler-Lopez and others (1999). During March 14-15, 2007, the U.S. Geological Survey (USGS), Caribbean Water Science Center (CWSC), in cooperation with the PREPA conducted a bathymetric survey of Lago Patillas to update the reservoir storage capacity and update the reservoir sedimentation rate by comparing the 2007 bathymetric survey data with previous 1997 data. The purpose of this report is to update the reservoir storage capacity, sedimentation rates, and areas of substantial sediment accumulation since April 1997.

Holocene climate variability and anthropogenic impacts from Lago Paixban, a perennial wetland in Peten, Guatemala

USGS Publications Warehouse

Wahl, David B.; Hansen, Richard D.; Byrne, Roger; Anderson, Lysanna; Schreiner, T.

2016-01-01

Analyses of an ~ 6 m sediment core from Lago Paixban in Peten, Guatemala, document the complex evolution of a perennial wetland over the last 10,300 years. The basal sediment is comprised of alluvial/colluvial fill deposited in the early Holocene. The absence of pollen and gastropods in the basal sediments suggests intermittently dry conditions until ~ 9000 cal yr. BP (henceforth BP) when the basin began to hold water perennially. Lowland tropical forest taxa dominated the local vegetation at this time. A distinct band of carbonate dating to ~ 8200 BP suggests regionally dry conditions, possibly associated with the 8.2 ka event. Wetter conditions during the Holocene Thermal Maximum are indicated by evidence of a raised water level and an open water lake. The timing of this interval coincides with strengthening of the Central American Monsoon. An abrupt change at 5500 BP involved the development of a sawgrass marsh and onset of peat deposition. The lowest recorded water levels date to 5500–4500 BP. Pollen, isotope, geochemical, and sedimentological data indicate that the coring site was near the edge of the marsh during this period. A rise in the water table after 4500 BP persisted until around 3500 BP. Clay marl deposition from 3500 to 210 BP corresponds to the period of Maya settlement. An increase in δ13C, the presence of Zea pollen, and a reduction in the percentage of forest taxa pollen indicate agricultural activity at this time. In contrast to several nearby paleoenvironmental studies, proxy evidence from Lago Paixban indicates human presence through the Classic/Postclassic period transition (~ 1000 BP) and persisting until the arrival of Europeans. Cessation of human activity around 210 BP resulted in local afforestation and the re-establishment of the current sawgrass marsh at Lago Paixban.

Holocene climate variability and anthropogenic impacts from Lago Paixban, a perennial wetland in Peten, Guatemala

NASA Astrophysics Data System (ADS)

Wahl, David; Hansen, Richard D.; Byrne, Roger; Anderson, Lysanna; Schreiner, Thomas

2016-03-01

Analyses of an 6 m sediment core from Lago Paixban in Peten, Guatemala, document the complex evolution of a perennial wetland over the last 10,300 years. The basal sediment is comprised of alluvial/colluvial fill deposited in the early Holocene. The absence of pollen and gastropods in the basal sediments suggests intermittently dry conditions until 9000 cal yr. BP (henceforth BP) when the basin began to hold water perennially. Lowland tropical forest taxa dominated the local vegetation at this time. A distinct band of carbonate dating to 8200 BP suggests regionally dry conditions, possibly associated with the 8.2 ka event. Wetter conditions during the Holocene Thermal Maximum are indicated by evidence of a raised water level and an open water lake. The timing of this interval coincides with strengthening of the Central American Monsoon. An abrupt change at 5500 BP involved the development of a sawgrass marsh and onset of peat deposition. The lowest recorded water levels date to 5500-4500 BP. Pollen, isotope, geochemical, and sedimentological data indicate that the coring site was near the edge of the marsh during this period. A rise in the water table after 4500 BP persisted until around 3500 BP. Clay marl deposition from 3500 to 210 BP corresponds to the period of Maya settlement. An increase in δ13C, the presence of Zea pollen, and a reduction in the percentage of forest taxa pollen indicate agricultural activity at this time. In contrast to several nearby paleoenvironmental studies, proxy evidence from Lago Paixban indicates human presence through the Classic/Postclassic period transition ( 1000 BP) and persisting until the arrival of Europeans. Cessation of human activity around 210 BP resulted in local afforestation and the re-establishment of the current sawgrass marsh at Lago Paixban.

CT-detected intracranial hemorrhage among patients with head injury in Lagos, Nigeria.

PubMed

Eze, Cletus Uche; Abonyi, Livinus Chibuzo; Olowoyeye, Omodele; Njoku, Jerome; Ohagwu, Christopher; Babalola, Sherifat

2013-01-01

To evaluate the computed tomography (CT) findings of intracranial hemorrhage among patients with head trauma in Lagos, Nigeria. In this retrospective, cross-sectional study, a convenience sample of 500 patients with head trauma who had diagnostic cranial CT scans was selected. All the radiological reports and CT scans of patients with head trauma were retrieved in the hospitals selected as study sites. The reports were sorted into 2 groups - normal findings and intracranial bleeding. The reports of intracranial bleeding were sorted again into different classes of intracranial bleeding as identified by the radiologist who reported it. All data were analyzed using the Epi Info public domain software package. The chi-square test was used to measure the statistical significance of study results at P < .05. Most of the study subjects (68%) were men. Traffic accidents accounted for 44% of all the head traumas found in the study, and 58% of the head traumas resulted in intracranial bleeding. Among the hemorrhages found, 37% were intracerebral, 25% were subdural, 16% were intraventricular, 15% were subarachnoid, and 7% were epidural. Intracranial hemorrhage was a common consequence of acute head trauma sustained from traffic accidents in the population studied, with intracerebral hemorrhage being the most prevalent type. Traffic accidents are the main cause of acute head trauma in Lagos, Nigeria. The use of CT for early diagnosis of intracranial hemorrhage appears justifiable.

Isolation of Lagos Bat Virus from Water Mongoose

PubMed Central

Markotter, Wanda; Kuzmin, Ivan; Rupprecht, Charles E.; Randles, Jenny; Sabeta, Claude T.; Wandeler, Alexander I.

2006-01-01

A genotype 2 lyssavirus, Lagos bat virus (LBV), was isolated from a terrestrial wildlife species (water mongoose) in August 2004 in the Durban area of the KwaZulu-Natal Province of South Africa. The virus isolate was confirmed as LBV by antigenic and genetic characterization, and the mongoose was identified as Atilax paludinosus by mitochondrial cytochrome b sequence analysis. Phylogenetic analysis demonstrated sequence homology with previous LBV isolates from South African bats. Studies performed in mice indicated that the peripheral pathogenicity of LBV had been underestimated in previous studies. Surveillance strategies for LBV in Africa must be improved to better understand the epidemiology of this virus and to make informed decisions on future vaccine strategies because evidence is insufficent that current rabies vaccines provide protection against LBV. PMID:17326944

Land-use effects on erosion, sediment yields, and reservoir sedimentation: a case study in the Lago Loiza Basin, Puerto Rico

USGS Publications Warehouse

Gellis, A.C.; Webb, R.M.T.; McIntyre, S.C.; Wolfe, W.J.

2006-01-01

 Lago Loíza impounded in 1953 to supply San Juan, Puerto Rico, with drinking water; by 1994, it had lost 47% of its capacity. To characterize sedimentation in Lago Loíza, a study combining land-use history, hillslope erosion rates, and subbasin sediment yields was conducted. Sedimentation rates during the early part of the reservoir’s operation (1953– 1963) were slightly higher than the rates during 1964–1990. In the early history of the reservoir, cropland comprised 48% of the basin and erosion rates were high. Following economic shifts during the 1960s, cropland was abandoned and replaced by forest, which increased from 7.6% in 1950 to 20.6% in 1987. These land-use changes follow a pattern similar to the northeastern United States. Population in the Lago Loíza Basin increased 77% from 1950 to 1990, and housing units increased 194%. Sheetwash erosion measured from 1991 to 1993 showed construction sites had the highest sediment concentration (61,400 ppm), followed by cropland (47,400 ppm), pasture (3510 ppm), and forest (2050 ppm). This study illustrates how a variety of tools and approaches can be used to understand the complex interaction between land use, upland erosion, fluvial sediment transport and storage, and reservoir sedimentation. 

ATTITUDES AND ACCEPTANCE OF NIGERIANS TOWARDS VASECTOMY--A COMPARISON OF MARRIED MEN AND WOMEN IN LAGOS.

PubMed

Tijani, K H; Ojewola, R W; Yahya, G L; Oluwole, A A; Odusanya, B

2013-03-01

Nigeria with a growth rate of 28%, accounts for over two thirds of the West African population. It also has one of the highest maternal mortality rates in the world with contraceptive prevalence among married couples less than 10%. Despite its safety and efficacy vasectomy appears to be unpopular in our environment. To assess the perception and acceptance of married men and women towards vasectomy and the influence of the spouse on the man's decision to accept or reject vasectomy. A cross sectional questionnaire based study. With an estimated population of 20 million, Lagos is the most cosmopolitan and urbanised city in Nigeria and accounts for 65% of all commercial activities in the country. Virtually all the tribes in Nigeria are represented in the city. Literate pregnant women recruited from the antenatal clinics and literate new fathers. All subjects were recruited from three health facilities in the Lagos metropolis. Twenty seven point five and twenty one percent of the men and women respectively had a good Knowledge of vasectomy while 49.1% and 19% of all men and women respectively with good knowledge would accept vasectomy (or agree for their spouses to have the procedure). Overall acceptance rates for men and women were 26 and 13.5% respectively while 92% of men who can opt for vasectomy will only do so if their spouses agree. Knowledge about vasectomy was the strongest single factor influencing the acceptance of vasectomy (p= 0.013) with stronger correlation among men than women (p=0.005 vrs p=.0.023). Knowledge and acceptance of vasectomy is significantly better in males than female Nigerians living in Lagos.

Evaluations of groundwater contamination by leachates around Olusosun open dumpsite in Lagos metropolis, southwest Nigeria.

PubMed

Aboyeji, Olatunji Sunday; Eigbokhan, Stephen Femi

2016-12-01

A major cause of groundwater pollution in urban areas is contamination by leachates emanating from municipal solid waste dumpsites. The study evaluated the quality of water of selected boreholes and wells around Olusosun open solid waste dumpsite in Lagos metropolis, using water quality index (WQI) rating and geospatial techniques. Water samples were randomly collected from fifteen boreholes and five wells downslopes of the dumpsite. The samples were analysed for the physico-chemical parameters and heavy metals. Factor Analysis was employed to analyse the information content of the water quality indicators to determine their appropriateness for indexing. The spatial distribution of the WQIs determined using Inverse Distance Weighting (IDW) interpolation procedure. Results showed that the waters were generally acidic with 85% of pH values below the range suggested by WHO for drinking water. All samples contained concentration of dissolved oxygen (DO) in quantities higher than the recommended limit of 2.0 mg/l (average = 4.97 mg/l), while 40% of the samples contained concentration of K above the recommended limit. The concentration of heavy metals was generally low. The major cations (Mg, Na, and K) were highly positively correlated, and were positively correlated with pH, TA, TAL, TH and Cl. Negative correlations were observed between TDS, NO3(-) and PO4(3-); NO3(-) and Ag; and DO with the heavy metals. Eighteen parameters consisting of pH, EC, TDS, TA, TAL, TH, Cl, NO3(-), PO4(3-), Mg, Na, K, Zn, Mn, Fe, Cd, Ag and Pb were found to be the main indicators of groundwater pollution caused by landfill leachate percolation. Evaluation of the WQIs indicated that 35% of the water samples were unsuitable for consumption, while 15%, 15% and 35% were in the good, very good and excellent categorises, respectively. The degree of suitability of the borehole and well waters was closely related to proximity to the dumpsite. It is imperative that appropriate remediation

Evidence of Lagos bat virus circulation among Nigerian fruit bats.

PubMed

Dzikwi, Asabe A; Kuzmin, Ivan I; Umoh, Jarlath U; Kwaga, Jacob K P; Ahmad, Aliyu A; Rupprecht, Charles E

2010-01-01

During lyssavirus surveillance, 350 brains from four species of fruit bats and one species of insectivorous bat were collected from seven locations in Northern Nigeria during May to October, 2006. Lyssavirus antigen was not detected in the brains, and isolation attempts in mice were unsuccessful. However, serologic tests demonstrated the presence of lyssavirus-neutralizing antibodies in bat sera. Of 140 sera tested, 27 (19%) neutralized Lagos bat virus, and two of these additionally neutralized Mokola virus. The positive samples originated from the straw-colored fruit bat (Eidolon helvum) and the Gambian epaulet bat (Epomophorus gambianus). No neutralizing activity was detected against other lyssaviruses including rabies, Duvenhage, and West Caucasian bat viruses.

"Their days are spent in gambling and loafing, pimping for prostitutes, and picking pockets": male juvenile delinquents on Lagos Island, 1920s - 1960s.

PubMed

Heap, Simon

2010-01-01

In recent times, Lagos Island has been hit by a cyclical crescendo of juvenile crime perpetrated by "Area Boys," jobless youths who deal in robbery, extortion, and blackmail. Such deviant behavior has historical roots back to colonial times, when youths labeled "alkali boys," "boma boys," and "cowboys" roamed the heart of the capital of Britain's colony of Nigeria between the 1920s and 1960s. Examining the various types of juvenile delinquents on Lagos Island, this article explores the urban experience of criminally minded youths through exploration of street-life, vagrancy, criminality, and public reactions.

Trip to Lago Nero (Tusco-Emilian Apennine, Italy): How has our Apennine been changing?

NASA Astrophysics Data System (ADS)

Papini, Piera; Vergari, Simone

2014-05-01

The sharp division of disciplines in Italian Secondary school is a problem which hinders the natural learning of pupils. At the end of the 1st education cycle, candidates must stand six written tests and an oral exam during which they present a topic that includes a lot of disciplines and that they develop unifying what they have been taught fragmentarily. Climate changes that are taking place and the use of Earth resources are a significant topic suitable for a multidisciplinary as well as interdisciplinary approach. Thanks to the Region of Tuscany, which has financed the Educational Contract " An agreement for water" (2012-2015), we could develop this module which involves 14 years old students and is focused on the climate change evidence in a lake, Lago Nero, originated in the Tusco-Emilian Apennine during the development of an ancient Wurmian glacier. The didactical path includes: - lessons in the classroom on weather, climate and climate changes caused both by nature and by man. - A focus on Lago Nero - A trip to Lago Nero, observation of the landscape geomorphology: differences between fluvial valleys and glacial valleys, signs of remote events such as roche mountonnée or recent ones such as landslides and floods caused by intense rainfalls. Collection of samples. - Participation at a conference organized by the Region at San Giorgio Library in Pistoia ( http://rinnoviamoci2011.blogspot.it/ ) during which students met some administrators and talked with them. A video made by the pupils was presented on this occasion. http://www.icsfrankcarradori.it/studenti/ Further activities include: - Open day for families of the younger pupils, during which older pupils explained some of the activities carried out, included the module on Lago Nero. - identification of minerals (connection with Chemestry) - identification of rocks outcropping in the area of the lake: what do they tell about geologic history of our mountains? How can they reveal the age of a geologic

A Study of Power Relations in Doctor-Patient Interactions in Selected Hospitals in Lagos State, Nigeria

ERIC Educational Resources Information Center

Adam, Qasim

2014-01-01

This paper explores power relations in clinical interactions in Nigeria. It seeks to investigate the use of power between doctors and patients during consultations on patient-centred approach to medicine in selected public and private hospitals in Lagos State, Nigeria. The objective is to establish how doctors' projection of power, using the…

Reconstruction of full glacial environments and summer temperatures from Lago della Costa, a refugial site in Northern Italy

NASA Astrophysics Data System (ADS)

Samartin, Stéphanie; Heiri, Oliver; Kaltenrieder, Petra; Kühl, Norbert; Tinner, Willy

2016-07-01

Vegetation and climate during the last ice age and the Last Glacial Maximum (LGM, ∼23,000-19,000 cal BP) were considerably different than during the current interglacial (Holocene). Cold climatic conditions and growing ice-sheets during the last glaciation radically reduced forest extent in Europe to a restricted number of so-called ;refugia;, mostly located in the southern part of the continent. On the basis of paleobotanical analyses the Euganian Hills (Colli Euganei) in northeastern Italy have previously been proposed as one of the northernmost refugia of temperate trees (e.g. deciduous Quercus, Tilia, Ulmus, Fraxinus excelsior, Acer, Abies alba, Fagus sylvatica, Carpinus and Castanea) in Europe. In this study we provide the first quantitative, vegetation independent summer air temperature reconstruction for Northern Italy spanning the time ∼31,000-17,000 cal yr BP, which covers the coldest periods of the last glacial, including the LGM and Heinrich stadials 1 to 3. Chironomids preserved in a lake sediment core from Lago della Costa (7m a.s.l.), a small lake at the south-eastern edge of the Euganean Hills, allowed quantitative reconstruction of Full and Late Glacial summer air temperatures using a combined Swiss-Norwegian temperature inference model based on chironomid assemblages from 274 lakes. Chironomid and pollen evidence from Lago della Costa derives from finely stratified autochthonous organic gyttja sediments, which excludes major sediment mixing or reworking. After reconstructing paleo-temperatures, we address the question whether climate conditions were warm enough to permit the local survival of temperate tree species during the LGM and whether local expansions and pollen-inferred contractions of temperate tree taxa coincided with chironomid-inferred climatic changes. Our results suggest that chironomids at Lago della Costa have responded to major climatic fluctuations such as temperature decreases during the LGM and Heinrich stadials. The

Addressing the Multiple Drivers of Wetland Ecosystems Degradation in Lagos, Nigeria

NASA Astrophysics Data System (ADS)

Agboola, J.; Ndimele, P. E.; Odunuga, S.; Akanni, A.; Kosemani, B.; Ahove, M.

2015-12-01

Several body of knowledge have noted the importance of wetland ecosystems in climate moderation, resource supply and flood risk reduction amongst others. Relevant as it may, rapidly increasing population and uncontrolled urban development poses a challenge in some regions and require understanding of the ecosystem components and drivers of change over a long period of time. Thus, the main thrust of this paper is to analyse multiple drivers of wetland ecosystems degradation in the last 30 years in the Lagos megacity using field study, desktop review, satellite data and laboratory analysis. Key drivers identified includes: conversion of wetlands to settlements and waste sink, land use planning that neglects wetland conservation and restoration, ineffective legal status for wetlands, over exploitation leading to degradation and fragmentation of wetland ecosystems governance. In stemming further loss of this vital ecosystem, this study adopted and proposed respectively, the Drivers, Pressure, State, Impact and Response (DPSIR) and Integrated Planning Approach (IPA) frameworks in analysing policy and governance issues in wetland development. These analyses figured out amongst others, strict conservation and sustainable use of wetland resources, habitat restoration, climate adaptation measures, legal protection and wetland management institution as major responses to current multiple pressures facing wetland ecosystems in Lagos. For these frameworks to be made meaningful, weak coordination among government agencies and institutional capacity in implementation and law enforcement, unsustainable resource extraction by private/business organization and issues on alternative sources of income on the part of the local communities amongst others needs to be addressed.

Assessment of the Regenerative Potential of Organic Waste Streams in Lagos Mega-City

NASA Astrophysics Data System (ADS)

Opejin, Adenike Kafayat

There is never a better time for this study than now when Nigeria as a country is going through the worst time in power supply. In Lagos city about 12,000 tons of waste is generated daily, and is expected to increase as the city adds more population. The management of these waste has generated great concern among professionals, academia and government agencies. This study examined the regenerative management of organic waste, which accounts for about 45% of the total waste generated in Lagos. To do this, two management scenarios were developed: landfill methane to electricity and compost; and analyzed using data collected during field work and from government reports. While it is understood that landfilling waste is the least sustainable option, this study argued that it could be a viable method for developing countries. Using U.S EPA LandGEM and the IPCC model, estimates of capturable landfill methane gas was derived for three landfills studied. Furthermore, a 35-year projection of waste and landfill methane was done for three newly proposed landfills. Assumptions were made that these new landfills will be sanitary. It was established that an average of 919,480,928m3 methane gas could be captured to generate an average of 9,687,176 MW of electricity annually. This makes it a significant source of power supply to a city that suffers from incessant power outages. Analysis of composting organics in Lagos was also done using descriptive method. Although, it could be argued that composting is the most regenerative way of managing organics, but it has some problems associated with it. Earthcare Compost Company processes an average of 600 tons of organics on a daily basis. The fraction of waste processed is infinitesimal compared to the rate of waste generated. One major issue identified in this study as an obstacle to extensive use of this method is the marketability of compost. The study therefore suggests that government should focus on getting the best out of the

Family Background, Sexual Behaviour, and HIV/AIDS Vulnerability of Female Street Hawkers in Lagos Metropolis, Nigeria

ERIC Educational Resources Information Center

Oyefara, John Lekan

2005-01-01

This article examines the sexual behaviour and the HIV/AIDS knowledge and vulnerability of female street hawkers in Lagos metropolis, Nigeria. A total of 126 female street hawkers under 18 were sampled in a cross-sectional survey and six Focus Group Discussions (FGDs) were conducted to generate data from respondents. Data on sexual behaviour…

Preventive and social cost implications of Ebola Virus Disease (EVD) outbreak on selected organizations in Lagos state, Nigeria

PubMed Central

Olugasa, Babasola Oluseyi; Oshinowo, Oluwafunmilola Yemisi; Odigie, Eugene Amienwanlen

2015-01-01

Introduction As Ebola virus disease (EVD) continues to pose public health challenge in West Africa, with attending fears and socio-economic implications in the current epidemic challenges. It is compelling to estimate the social and preventive costs of EVD containment in a Nigerian city. Hence, this study was to determine the social and preventive cost implications of EVD among selected public institutions in Lagos, Nigeria, from July to December, 2014. Methods Questionnaires and key-informants interview were administered to respondents and administrators of selected hospitals, hotels and schools in Eti-Osa Local Government Area of Lagos State. Knowledge of disease transmission, mortality and protocols for prevention, including cost of specific preventive measures adopted against EVD were elicited from respondents. Descriptive statistics and categorical analysis were used to summarize and estimate social and preventive costs incurred by respective institutions. Results An estimated five million, nineteen thousand, three hundred and seventy-nine Naira and eighty kobo (N5,019,379.80) only was observed as direct and social cost implication of EVD prevention. This amount translated into a conservative estimate of one billion, twenty-seven million, ninety-four thousand, seven hundred and fifty-six Naira (N1,027,094,756.10) for a total of four thousand schools, two hundred and fifty-three hospitals and one thousand, four hundred and fifty one hotels in Lagos during the period (July 20-November 20, 2014). Conclusion The high cost of prevention of EVD within the short time-frame indicated high importance attached to a preventive policy against highly pathogenic zoonotic disease in Nigeria. PMID:26740848

Preparedness of government owned dental clinics for the management of medical emergencies: a survey of government dental clinics in Lagos.

PubMed

Gbotolorun, O M; Babatunde, L B; Osisanya, O; Omokhuale, E

2012-01-01

An emergency is a medical condition demanding immediate treatments. The aim of the study was to determine the knowledge and ability of dental surgeons in the management of medical emergencies and the availability of emergency drugs and equipment in government dental clinics and hospitals in Lagos State. The study was a descriptive cross-sectional study of knowledge and ability of Dental Surgeons in the management of medical emergencies, prevalence of medical emergencies in dental practice and availability of emergency drugs and equipment in dental practice in government dental clinics and hospitals in Lagos State. The study covered 22 government dental clinics and hospitals in Lagos State. Data obtained was entered into a computerand analyzed using Statistical Package for Social Science (SPSS) Version-16 data analysis software. Chi Square and cross-tabulations were used for the analysis. A 95% Confidence Level was used and a p-value of less than or equal to 0.05 was considered statistically significant. Of a population of 255 Dental Surgeons on the nominal rolls of all the health institutions, 224 (87%)responded.Of the total respondents, 204 (91.1%) stated they had no emergency kit in their dental clinics (p < 0.05) while 158 respondents (70.5%) stated they had no emergency drugs in their dental practice to manage medical emergencies (p < 0.05). The commonest emergencies reported was syncope 104 respondents (33.8%). 161 respondents (71.9%) claimed they are able to manage medical emergencies encountered in their dental practice if kits and drugs are available. The findings of the study show that government dental clinics/hospital in Lagos seem not to be adequately prepared to manage medical emergency. Although 71.9% of the dentist claimed they could mange such emergencies should they arise 91.1% and 70% of the respondent claimed they and no emergency kits and drugs to manage such emergencies in their hospital respectively should they arise.

Assessment of Day Caring Methods among Civil Servant Mothers of Reproductive Age in Lagos State Nigeria

ERIC Educational Resources Information Center

Akinnubi, Caroline Funmbi

2016-01-01

This study examined the day caring methods among the civil servants of reproductive age with children between three months to four years in Lagos State Nigeria. The research design employed for this study was a descriptive research design. A total number of 212 teachers and 128 ministry workers making a total of 340 reproductive age mothers were…

Desarrollo de un detector de rayos cósmicos de la colaboración LAGO en Buenos Aires - Aplicaciones en meteorología espacial

NASA Astrophysics Data System (ADS)

Coppola, M.; Bezzecchi, F.; Gulisano, A. M.; Masías-Meza, J. J.; Areso, O.; Ramelli, M.; Dasso, S.; LAGO Collaboration

2016-08-01

The study of low energy cosmic particles allows to analyze several aspects of major interest for space weather. Ground detectors permit to observe secundary particles produced during the cascades developed in the atmosphere. The characterization of a prototype for a water Cherenkov radiation particles detector, in the frame of the LAGO collaboration (Latin American Giant Observatory), is presented in this work. The collaboration plans to install this detector at the LAGO antarctic site. The developed acquisition system and the method used to make the energy callibration of the detector are detailed here, as also corrections for atmospheric effects.

Expanding Access for Training of Science Teachers through ODL: A Case Study of University of Lagos, Nigeria

ERIC Educational Resources Information Center

Okunuga, A. O.; Olaoluniyi, O.; Opara, A. I.

2013-01-01

Rising up to the challenge of shortage of middle manpower in Nigeria, the University of Lagos established the Correspondence and Open Studies Unit (COSU), now Distance Learning Institute DLI). Accounting, Business Administration and Science-Education were the pilot courses at the B.Sc. level. The Special Entry Preparatory Programme (SEPP) was…

Herbal medicines supplied by community pharmacies in Lagos, Nigeria: pharmacists’ knowledge

PubMed Central

Oshikoya, Kazeem Adeola; Oreagba, Ibrahim A.; Ogunleye, Olayinka O.; Oluwa, Rashidat; Senbanjo, Idowu O.; Olayemi, Sunday O.

Background The use of herbal medicines is on the increase globally and they are usually supplied in pharmacies as non-prescription medicines. Pharmacists are, therefore, responsible for educating and informing the consumers about rational use of herbal medicines. Objective To evaluate the knowledge of pharmacists in Lagos, Nigeria with regards to the herbal medicines they supplied by their pharmacies. Methods Pharmacists in charge of randomly selected 140 community pharmacies from 20 Local Government Areas in Lagos were required to fill out a self-administered questionnaire. We gathered information on their knowledge of the indications, adverse effects, potential drug-herb interactions and contraindications of the herbal medicines they supply in their pharmacies. Results Of the 140 questionnaires distributed, 103 (72.9%) participants completed the questionnaire appropriately. The majority (74; 71.8%) of the participants were males and 36-50 years (56; 54.4%). The pharmacies supplied mostly Yoyo cleanser bitters® (101; 98.5%), ginseng (97; 98.5%), Jobelyn® (91; 88.3%), Ciklavit® (68; 66.6%), gingko (66; 64.1%), herbal tea (66; 64.1%), and Aloe vera (57; 55.3%). The pharmacists self-rated their knowledge of herbal medicines mostly as fair (39%) and good (42%), but they exhibited poor knowledge with regards to the indications, contraindications and safety profiles. Seventy participants consulted reference materials such as leaflet insert in the herbal medicines (56%) and internet (20%) before supplying herbal medicines. The information most frequently sought was herb-drug interactions (85%), contraindications (75%) and adverse effects (70%). Conclusions Community pharmacists need to be informed about the indications and safety profiles of herbal medicines. PMID:24367462

Unmasking inequalities: Sub-national maternal and child mortality data from two urban slums in Lagos, Nigeria tells the story.

PubMed

Anastasi, Erin; Ekanem, Ekanem; Hill, Olivia; Adebayo Oluwakemi, Agnes; Abayomi, Oluwatosin; Bernasconi, Andrea

2017-01-01

Nigeria has one of the highest maternal mortality ratios in the world as well as high perinatal mortality. Unfortunately, the country does not have the resources to assess this critical indicator with the conventional health information system and measuring its progress toward the goal of ending preventable maternal deaths is almost impossible. Médecins Sans Frontières (MSF) conducted a cross-sectional study to assess maternal and perinatal mortality in Makoko Riverine and Badia East, two of the most vulnerable slums of Lagos. The study was a cross-sectional, community-based household survey. Nearly 4,000 households were surveyed. The sisterhood method was utilized to estimate maternal mortality and the preceding births technique was used to estimate newborn and child mortality. Questions regarding health seeking behavior were posed to female interviewees and self-reported data were collected. Data was collected from 3963 respondents for a total of 7018 sisters ever married. The maternal mortality ratio was calculated at 1,050/100,000 live births (95% CI: 894-1215), and the lifetime risk of maternal death at 1:18. The neonatal mortality rate was extracted from 1967 pregnancies reported and was estimated at 28.4/1,000; infant mortality at 43.8/1,000 and under-five mortality at 103/1,000. Living in Badia, giving birth at home and belonging to the Egun ethnic group were associated with higher perinatal mortality. Half of the last pregnancies were reportedly delivered in private health facilities. Proximity to home was the main influencing factor (32.4%) associated with delivery at the health facility. The maternal mortality ratio found in these urban slum populations within Lagos is extremely high, compared to the figure estimated for Lagos State of 545 per 100,000 live births. Urgent attention is required to address these neglected and vulnerable neighborhoods. Efforts should be invested in obtaining data from poor, marginalized, and hard-to-reach populations in

Strategies for Introducing New Curricula in West Africa. Final Report of the Seminar/Workshop (Lagos, Nigeria, November 12-16, 2001) (Strategies d'Adaptation des Nouveaux Curricula en Afrique de l'Ouest. Rapport Final du Seminaire/Atelier (Lagos, Nigeria, 12-16 Novembre 2001).

ERIC Educational Resources Information Center

Pillai, Sharmila, Ed.

The central theme of the Lagos, Nigeria, seminar/workshop was recognition for the teaching profession, particularly as being the most important educational change agent. Part 1, "Thematic Issues" includes: "Language Curriculum and Teaching in Multilingual Environments" (Sharmila Pillai); "The Situation in Nigeria" (E.…

Pattern of periodontal treatments performed at the periodontology clinic of the Lagos University Teaching Hospital: 22 months review.

PubMed

Umeizudike, K A; Ayanbadejo, P O; Savage, K O; Taiwo, O A

2012-01-01

A critical evaluation of the pattern of periodontal procedures performed is important in providing useful data to the administrator for proper planning and budgeting for dental health service. To assess the pattern of periodontal treatments performed over a given period of time at the Periodontology clinic of the Lagos University Teaching Hospital, Lagos, Nigeria. This was a twenty two months retrospective study of all periodontal procedures performed on patients seen at the periodontology clinic of the Lagos University Teaching Hospital between January 2006 and October 2007. The periodontology treatment record was used to retrieve information which included the patient's age, gender, diagnosis and periodontal procedures given. The procedures were further categorized into surgical and nonsurgical groups. The information obtained was then analyzed using Epi Info 2007 statistical software. A total of 1,938 patients were seen during this period. Females were 1009 (52.1%) and males were 929 (47.9%). (F/M, 1.1:1). A total of 2,110 periodontal treatments were performed. Majority of the patients received non-surgical periodontal therapy which constituted the bulk (96.3%) of the therapies. Scaling and polishing was the most frequently performed non-surgical procedure accounting for 1261 (62.1%) with slightly more males receiving the treatment. Of the surgical treatment modalities, operculectomy accounted for 65.4% and was carried out on more females than males. Regenerative procedures were the least performed surgical treatments. This study highlighted that non-surgical periodontal therapy, particularly scaling and polishing was the most frequently utilized periodontal procedure. Operculectomy was the predominant surgical procedure performed. The low percentage of regenerative surgical procedures was however below the desired expectation.

HIV association with conventional STDS (sexual transmitted diseases) in Lagos State, Nigeria.

PubMed

Otuonye, N M; Olukoya, D K; Odunukwe, N N; Idigbe, E O; Udeaja, M N; Bamidele, M; Onyewuchie, J I; Oparaugu, C T; Ayelari, O S; Oyekunle, B

2002-01-01

The study examined a possible association between HIV infection and conventional sexually transmitted diseases (STDS) in a population of 700 patients seen in some hospitals and clinics in Lagos State between November 1997 and December 1999. The patients were drawn mainly from LUTH and Jolad hospitals in Lagos State. In these hospitals, patients who presented with symptoms of STDS were screened clinically and microbiologically for agents of STDS and HIV antibodies. Screening was carried out using conventional methods. A total of 150 (21.5%) were found positive for various STDS while 550 (78.5%) were negative Also, 109 (15.8%) were sero-positive for HIV while 591 (84.4%) were sero-negative. The frequency of STDS diagnosed were, Treponema pallidum, 38(25.3%), Neisseria gonorrhoea 3(2.0%), Chlamydia trachomatis 26(17.3), Hepatitis B virus 60(40.0%) Staphylococcus aureaus, 20 (13.3%) and Candida albicans 3(2.0%). Data showed that Syphillis was the most prevalent STDS diagnosed while Calbicans and N. gonorrhoea are the least. Amongst the 150 (21.5%) patients positive with STDS, 82(54.65%) were found to be positive for HIV antibodies. The remaining 68(45.3%) patients were negative for HIV. The difference in sero-prevalence on the true group of patients rates was significant. The higher rate in the STDS patients strongly suggest some association between HIV infections andSTDS amongst the patients studied p = 0.05. It was also recorded that HIV-1 infection is four times more prevalent than HIV-2 in these patients.

Histopathological report of colorectal carcinoma resections: A 5-year audit in Lagos.

PubMed

Badmos, Kabir Bolarinwa; Rotimi, Olorunda; Lawal, Abdulrazzaq Oluwagbemiga; Osinowo, Adedapo O; Habeebu, Mohammed Y; Abdulkareem, Fatimah Biade

2018-01-01

Complete and accurate pathology reporting of colorectal carcinoma (CRC) resection specimen is critical to clinical management of individual patients. The study aims to audit colorectal cancer histopathology reporting in Lagos between 2011 and 2015 before the adoption of the Society for Gastroenterology and Hepatology in Nigeria pro forma in 2016. All resected CRC cases were identified from the Histopathology record of our Department and that of a private Laboratory in Lagos over a 5-year from 2011 to 2015. The dataset as contained in the pro forma was extracted from the reports and analysed using SPSS version 16 software. A total of 92 colorectal resections were received during the 5-year period consisting of 90 colonic and 2 rectal tumours. Data inclusiveness on tumour differentiation, extent of primary tumour, total lymph node and lymph node involvement were 96.7%, 91.3%, 83.7% and 92.4%, respectively. Tumour perforation, level of venous involvement and distant metastasis were reported in 73.9%, 21.7% and 96.7% respectively. The circumferential resection margin (CRM) in the 2 rectal tumours had 100% inclusiveness. Tumour node metastasis staging was complete in 87% of cases while Dukes staging was documented in 8.7% of the reports. None of the data items was 100% complete except the CRM for rectal carcinoma. Free text reporting results in incomplete data resulting in improper staging, especially the lymph node status. This highlights the need for pro forma reporting to ensure and maintain consistent reporting of important parameters required for proper staging and management of patients with colorectal cancer.

Home and School Environments as Determinant of Social Skills Deficit among Learners with Intellectual Disability in Lagos State

ERIC Educational Resources Information Center

Isawumi, Oyeyinka David; Oyundoyin, John Olusegun

2016-01-01

The study examined home and school environmental factors as determinant of social skills deficit among learners with intellectual disability in Lagos State, Nigeria. The study adopted survey research method using a sample size of fifty (50) pupils with intellectual disability who were purposively selected from five special primary schools in Lagos…

Private and Public Schooling in Low-Income Areas of Lagos State, Nigeria: A Census and Comparative Survey

ERIC Educational Resources Information Center

Tooley, James; Dixon, Pauline; Olaniyan, Olanrewaju

2005-01-01

A census and survey of schools in selected poor areas of Lagos State explored the nature and extent of private education, and compared inputs to public and private schooling. Of all schools (71%) were found to be private, with more unregistered private than government and registered private schools. It was estimated that 33% of school children…

Access or Quality? Why Do Families Living in Slums Choose Low-Cost Private Schools in Lagos, Nigeria?

ERIC Educational Resources Information Center

Härmä, Joanna

2013-01-01

Lagos is home to 12,098 private schools catering to 57% of the state's enrolled children, from ultra-rich to relatively poor households, with many schools targeting those of lower socio-economic status. Government schools were intended to provide a just and equitable option for all; however, they have not kept pace with demand in terms of both…

Private sector participation in domestic waste management in informal settlements in Lagos, Nigeria.

PubMed

Opoko, Akunnaya P; Oluwatayo, Adedapo A

2016-12-01

Lagos is one of the fastest growing cities in Africa, which is grappling with the challenges of poorly managed urbanisation. With an estimated population of about 17.5 million, solid waste management is one of the most pressing environmental challenges currently faced in the city. It is estimated that more than 9071847.4kg of urban waste is generated every day in the city. The city lacks the capacity to deal with such magnitude of waste. Consequently, the city has involved the private sector (private sector participation) in its waste management drive. This article examines the effectiveness of this public-private sector collaboration model in waste management in informal settlements in Lagos using empirical data. Major findings of the article include the irregularity of waste collection owing to a poor road network, an inadequate transport infrastructure and the desire to maximise profit, as well as poor waste handling and disposal methods by the private sector participation operators who are not chosen based on competence and capacity to perform. Another major finding is the lack of cooperation from residents evidenced in non-payment of bills and poor packaging of wastes, resulting in wastes being littered. The article concludes on the need to restructure the scheme through proper sensitisation of residents, selection of operators with demonstrable delivery capacity and provision of a well-maintained road network to facilitate access of operators to settlements. © The Author(s) 2016.

Mobile phones for retinopathy of prematurity screening in Lagos, Nigeria, sub-Saharan Africa.

PubMed

Oluleye, Tunji S; Rotimi-Samuel, Adekunle; Adenekan, Adetunji

2016-01-01

Retinopathy of prematurity (ROP), thought to be rare in Nigeria, sub-Saharan Africa, has been reported in recent studies. Developing cost-effective screening is crucial for detecting retinal changes amenable to treatment. This study describes the use of an iPhone combined with a 20-D lens in screening for ROP in Lagos, Nigeria. The ROP screening program was approved by the Lagos University Teaching Hospital Ethical Committee. Preterm infants with birthweight of less than 1.5 kg or gestational age of less than 32 weeks were screened. In conjunction with the neonatologist, topical tropicamide (0.5%) and phenylephrine (2.5%) was used to dilate the pupils. A pediatric lid speculum was used. Indirect ophthalmoscopy was used to examine the fundus to ensure there were no missed diagnoses. An iPhone 5 with 20-D lens was used to examine the fundus. The App Filmic Pro was launched in the video mode. The camera flash served as the source of illumination. Its intensity was controlled by the app. The 20-D lens was used to capture the image of the retina, which was picked up by the camera system of the mobile phone. Another app, Aviary, was used to edit the picture. The images captured by the system were satisfactory for staging and determining the need for treatment. An iPhone combined with a 20-D lens appear to be useful in screening for ROP in resource-poor settings. More studies are needed in this area.

Urban malaria treatment behaviour in the context of low levels of malaria transmission in Lagos, Nigeria.

PubMed

Brieger, W R; Sesay, H R; Adesina, H; Mosanya, M E; Ogunlade, P B; Ayodele, J O; Orisasona, S A

2001-01-01

Urban malaria in West Africa is not well documented. While rapid urbanisation may create environmental conditions that favour mosquito breeding, urban pollution may inhibit the growth of Anopheles species. In 1996, the Basic Support for Institutionalizing Child Survival (BASICS) Project of the U.S. Agency for International Development (USAID) started building urban community health coalitions in Lagos, Nigeria, to empower communities to provide prompt treatment and appropriate prevention for major causes of childhood morbidity and mortality, including malaria, diarrhoeal disease, acute respiratory infections and vaccine preventable diseases. Intervention against malaria was predicated on national policies that assumed Nigeria was holo-endemic for malaria and that prompt treatment of febrile illness with anti-malarial drugs was an appropriate action. At the suggestion and with the assistance of another USAID programme, the Environmental Health Project (EHP), BASICS embarked on a rapid assessment of the epidemiological, entomological and sociological situation of malaria transmission and case management in three Lagos communities. During April and May 1998, blood film investigation of 916 children between the ages of 6 months and 5 years yielded a parasite prevalence rate of 0.9%. Night knockdown collections of mosquitoes in rooms yielded only C. quinquefasciatus and A. aegypti. The same results were obtained for night landing collections on human bait. Very low densities of A. gambiae larvae were found in breeding sites in Lagos Island (0.7) and Ajegunle (0.3). In contrast, community members, during focus group discussion identified malaria, in it various culturally defined forms, as a major health problem. Among the children examined clinically, 186 (20.3%) reported an illness, which they called "malaria" in the previous two weeks, and 180 had sought treatment for this illness. Data obtained from 303 shops in the area documented that a minimum of US dollars 4

Serpentinite-driven Exhumation of the UHP Lago di Cignana Unit in the Fossil Alpine Plate Interface

NASA Astrophysics Data System (ADS)

Scambelluri, M.; Gilio, M.; Angiboust, S.; Godard, M.; Pettke, T.

2015-12-01

The Lago di Cignana Unit (LCU) is a coesite- [1] and diamond-bearing [2] slice of oceanic-derived eclogites and metasediments recording Alpine UHP metamorphism at 600 °C-3.2 GPa (~110 km depth) [3]. The LCU is tectonically sandwiched between the eclogitic Zermatt-Saas Zone (ZSZ; 540 °C-3.2 GPa) [4] and the blueschist Combin Zone (400 °C-0.9 GPa) [5] along a tectonic structure joining HP units recording a ~1.2 GPa (40 km) pressure difference. So far, the ZSZ has been attributed to normal HP conditions and the mechanism driving exhumation and accretion of the LCU in its present structural position is not fully understood.We performed petrography and bulk-rock trace element analyses of rocks from LCU and ZSZ serpentinites. We observed that, while serpentinites in the core of the ZSZ show normal subduction zone trace elements and REE's patterns, the Ol+Ti-chu+Chl veins and host serpentinites enveloping the LCU are strongly enriched in sediment-derived fluid-mobile elements (U, Th, Nb, Ta, Ce, Y, As, Sb) and REE's: their patterns well match those of the closely associated LCU-UHP rocks.The presence of extremely enriched Ol+Ti-chu+Chl veins in the serpentinites at direct contact with the UHP Lago di Cignana Unit suggests that fluid exchange between serpentinite and LCU crustal rocks occurred at peak metamorphic conditions. Their coupling therefore occurred during subduction burial and/or peak UHP conditions. As such, the buoyancy force originating from the relatively light serpentinites fuelled the exhumation of the Lago di Cignana Unit. In this contest, the tectonic contact between the Zermatt-Saas Zone and the Combin Zone evolved into a true tectonic plate interface surface.1. Reinecke (1998). Lithos 42(3), 147-189; 2. Frezzotti et al. (2011). Nat. Geosci. 4(10), 703-706; 3. Groppo et al. (2009). J. Metam. Geol. 27(3), 207-231; 4. Angiboust et al. (2009). Terra Nova 21(3), 171-180; 5. Reddy et al. (1999). J. Metam. Geol. 17, 573-590.

Patient refusal of glaucoma surgery and associated factors in Lagos, Nigeria.

PubMed

Adekoya, Bola Josephine; Akinsola, Feyisayo B; Balogun, Bola Grace; Balogun, Modupe Medinat; Ibidapo, Olajumoke O

2013-01-01

To determine the prevalence of patient refusal of glaucoma surgery (GSR) and the associated factors in Lagos, Nigeria. A multicenter cross-sectional survey was conducted in Lagos state, Nigeria. Twelve centres were invited to participate, but data collection was completed in 10. Newly diagnosed glaucoma patients were recruited and interviewed from these sites over a four week period on prior awareness of glaucoma, surgery refusal, and reason(s) for the refusal. Presenting visual acuity was recorded from the patient files. The odds ratio and 95% confidence intervals (CI) were calculated. A total of 208 newly diagnosed glaucoma patients were recruited. Sixty-five (31.2%) patients refused surgery. Fear of surgery (31 (47.7%) patients), and fear of going blind (19 (29.2%) patients) were the most common reasons. The odds ratio of surgery refusal were marital status - not married versus married (2.0; 95% CI, 1.02-3.94), use of traditional medication - users versus non users (2.4; 95% CI, 1.1-5.2), perception of glaucoma causing blindness - no versus yes (3.7; 95% CI, 1.3-10.5), type of institution - government versus private (5.7; 95% CI, 1.3-25.1), and visual acuity in the better eye - normal vision versus visual impairment (2.3; 95% CI, 1.1-4.9). Age, gender, level of education, family history of glaucoma, and prior awareness of the diagnosis of glaucoma, were not significantly associated with surgery refusal. Perception of patients concerning glaucoma blindness was the strongest factor on multivariate analysis. GSR was relatively low in this study. Unmarried status, use of traditional medications, perception that glaucoma cannot cause blindness, government hospital patients, and good vision in the better eye were associated with GSR. These factors might help in the clinical setting in identifying appropriate individuals for targeted counseling, as well as the need for increased public awareness about glaucoma.

Coliform and metal contamination in Lago de Colina, a recreational water body in Chihuahua State, Mexico.

PubMed

Rubio-Arias, Hector; Rey, Nora I; Quintana, Rey M; Nevarez, G Virginia; Palacios, Oskar

2011-06-01

Lago de Colina (Colina Lake) is located about 180 km south of the city of Chihuahua (Mexico), and during the Semana Santa (Holy Week) vacation period its recreational use is high. The objective of this study was to quantify coliform and heavy metal levels in this water body before and after the Holy Week vacation period in 2010. Twenty sampling points were randomly selected and two water samples were collected at each point near the surface (0.30 m) and at 1 m depth. After the Holy Week vacation the same twenty points were sampled at the same depths. Therefore, a total 80 water samples were analyzed for fecal and total coliforms and levels of the following metals: Al, As, B, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Se, Si and Zn. It was hypothesized that domestic tourism contaminated this water body, and as a consequence, could have a negative impact on visitor health. An analysis of variance (ANOVA) study was performed for each element and its interactions considering a factorial design where factor A was sample date and factor B was sample depth. Fecal coliforms were only detected at eight sampling points in the first week, but after Holy Week, both fecal and total coliforms were detected at most sampling points. The concentrations of Al, B, Na, Ni and Se were only statistically different for factor A. The levels of Cr, Cu, K and Mg was different for both date and depth, but the dual factor interaction was not significant. The amount of Ca and Zn was statistically different due to date, depth and their interaction. No significant differences were found for any factor or the interaction for the elements As, Fe and Mn. Because of the consistent results, it is concluded that local tourism is contaminating the recreational area of Colina Lake, Chihuahua, Mexico.

Coliform and Metal Contamination in Lago de Colina, a Recreational Water Body in Chihuahua State, Mexico

PubMed Central

Rubio-Arias, Hector; Rey, Nora I.; Quintana, Rey M.; Nevarez, G. Virginia; Palacios, Oskar

2011-01-01

Lago de Colina (Colina Lake) is located about 180 km south of the city of Chihuahua (Mexico), and during the Semana Santa (Holy Week) vacation period its recreational use is high. The objective of this study was to quantify coliform and heavy metal levels in this water body before and after the Holy Week vacation period in 2010. Twenty sampling points were randomly selected and two water samples were collected at each point near the surface (0.30 m) and at 1 m depth. After the Holy Week vacation the same twenty points were sampled at the same depths. Therefore, a total 80 water samples were analyzed for fecal and total coliforms and levels of the following metals: Al, As, B, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Se, Si and Zn. It was hypothesized that domestic tourism contaminated this water body, and as a consequence, could have a negative impact on visitor health. An analysis of variance (ANOVA) study was performed for each element and its interactions considering a factorial design where factor A was sample date and factor B was sample depth. Fecal coliforms were only detected at eight sampling points in the first week, but after Holy Week, both fecal and total coliforms were detected at most sampling points. The concentrations of Al, B, Na, Ni and Se were only statistically different for factor A. The levels of Cr, Cu, K and Mg was different for both date and depth, but the dual factor interaction was not significant. The amount of Ca and Zn was statistically different due to date, depth and their interaction. No significant differences were found for any factor or the interaction for the elements As, Fe and Mn. Because of the consistent results, it is concluded that local tourism is contaminating the recreational area of Colina Lake, Chihuahua, Mexico. PMID:21776236

Design of a residential microgrid in Lagos del Cacique, Bucaramanga, Colombia

NASA Astrophysics Data System (ADS)

Bellon, D.; González Estrada, O. A.; Martínez, A.

2017-12-01

In this paper is presented a model that analyses the options to provide energy to an interconnected house in Lagos del Cacique, Bucaramanga, Colombia. Three power supplies were considered: photovoltaic, 1 kW wind turbine, and a 2.6kW gasoline generator, as well as a battery for energy storage. The variables considered for the sensitivity analysis correspond to the price of gasoline and the variation in loads. The simulation results suggest an optimal configuration of microgrids in generator-photovoltaic panel-battery. Sensitivity variables were specified in order to evaluate the effect of uncertainty. The simulation was done through the Homer software and the results of the combinations of sources are suggestions of the same.

Technical quality of delivery care in private- and public-sector health facilities in Enugu and Lagos States, Nigeria.

PubMed

Hirose, Atsumi; Yisa, Ibrahim O; Aminu, Amina; Afolabi, Nathanael; Olasunmbo, Makinde; Oluka, George; Muhammad, Khalilu; Hussein, Julia

2018-06-01

Private-sector providers are increasingly being recognized as important contributors to the delivery of healthcare. Countries with high disease burdens and limited public-sector resources are considering using the private sector to achieve universal health coverage. However, evidence for the technical quality of private-sector care is lacking. This study assesses the technical quality of maternal healthcare during delivery in public- and private-sector facilities in resource-limited settings, from a systems and programmatic perspective. A summary index (the skilled attendance index, SAI), was used. Two-staged cluster sampling with stratification was used to select representative samples of case records in public- and private-sector facilities in Enugu and Lagos States, Nigeria. Information to assess criteria was extracted, and the SAI calculated. Linear regression models examined the relationship between SAI and the private and public sectors, controlling for confounders. The median SAI was 54.8% in Enugu and 85.7% in Lagos. The private for-profit sector's SAI was lower than and the private not-for-profit sector's SAI was higher than the public sector in Enugu [coefficient = -3.6 (P = 0.018) and 12.6 (P < 0.001), respectively]. In Lagos, the private for-profit sector's SAI was higher and the private not-for-profit sector's SAI was lower than the public sector [3.71 (P = 0.005) and -3.92 (P < 0.001)]. Results indicate that the technical quality of private for-profit providers' care was poorer than public providers where the public provision of care was weak, while private for-profit facilities provided better technical quality care than public facilities where the public sector was strong and there was a relatively strong regulatory body. Our findings raise important considerations relating to the quality of maternity care, the public-private mix and needs for regulation in global efforts to achieve universal healthcare.

Issues Surrounding HIV Status Disclosure: Experiences of Seropositive Women in Lagos, Nigeria

PubMed Central

Oseni, Oluwaseun E.; Okafor, Ifeoma P.; Sekoni, Adekemi O.

2017-01-01

Background: Disclosure of human immunodeficiency virus (HIV) seropositivity by infected women is crucial in HIV control. To determine the rates, patterns, effects, and determinants of disclosure of status among HIV-positive women in Lagos, Nigeria. Methods: This was a descriptive cross-sectional study. Simple random sampling method was used to select 364 HIV-positive women accessing care in HIV treatment centers in Lagos Island. Data were collected using interviewer-administered questionnaires and analyzed with Epi Info (version 3.5.3). Inferential statistics done was Chi-square test and level of statistical significance was set at <5%. Results: Mean age of respondents was 37.3 ± 3 years, and most were married or cohabiting in monogamous families. The disclosure rates were 81.9% to anyone (excluding a health care professional); 60.4% to spouse/sexual partners; and 67.7% disclosed on the same day of diagnosis. Main reasons for disclosure were failing health (49.3%) and a sense of responsibility to the spouse/sexual partner (33.6%). Major reasons for nondisclosure were negative public opinion (84.8%) and fear of losing relationships (40.3%). Positive reactions following disclosure were mostly acceptance: 75.2% (family member) and 72.3% (spouse/sexual partner) while blame was the main negative outcome. Longer duration of diagnosis significantly improved disclosure to anyone (P < 0.001). Older age (P < 0.001) and awareness of spouse/sexual partner's HIV status (P < 0.001) significantly improved disclosure to spouse/sexual partner. Conclusions: Many respondents had not disclosed their status and require support and counseling to do so. Community education regarding stigmatization should be intensified. PMID:28966749

Unmasking inequalities: Sub-national maternal and child mortality data from two urban slums in Lagos, Nigeria tells the story

PubMed Central

Adebayo Oluwakemi, Agnes; Abayomi, Oluwatosin

2017-01-01

Introduction Nigeria has one of the highest maternal mortality ratios in the world as well as high perinatal mortality. Unfortunately, the country does not have the resources to assess this critical indicator with the conventional health information system and measuring its progress toward the goal of ending preventable maternal deaths is almost impossible. Médecins Sans Frontières (MSF) conducted a cross-sectional study to assess maternal and perinatal mortality in Makoko Riverine and Badia East, two of the most vulnerable slums of Lagos. Materials and methods The study was a cross-sectional, community-based household survey. Nearly 4,000 households were surveyed. The sisterhood method was utilized to estimate maternal mortality and the preceding births technique was used to estimate newborn and child mortality. Questions regarding health seeking behavior were posed to female interviewees and self-reported data were collected. Results Data was collected from 3963 respondents for a total of 7018 sisters ever married. The maternal mortality ratio was calculated at 1,050/100,000 live births (95% CI: 894–1215), and the lifetime risk of maternal death at 1:18. The neonatal mortality rate was extracted from 1967 pregnancies reported and was estimated at 28.4/1,000; infant mortality at 43.8/1,000 and under-five mortality at 103/1,000. Living in Badia, giving birth at home and belonging to the Egun ethnic group were associated with higher perinatal mortality. Half of the last pregnancies were reportedly delivered in private health facilities. Proximity to home was the main influencing factor (32.4%) associated with delivery at the health facility. Discussion The maternal mortality ratio found in these urban slum populations within Lagos is extremely high, compared to the figure estimated for Lagos State of 545 per 100,000 live births. Urgent attention is required to address these neglected and vulnerable neighborhoods. Efforts should be invested in obtaining data from

A Bayesian Belief Network Approach to Explore Alternative Decisions for Sediment Control and water Storage Capacity at Lago Lucchetti, Puerto Rico

EPA Science Inventory

A Bayesian belief network (BBN) was developed to characterize the effects of sediment accumulation on the water storage capacity of Lago Lucchetti (located in southwest Puerto Rico) and to forecast the life expectancy (usefulness) of the reservoir under different management scena...

New Prof Omeje Pornography Addiction as Correlate of Psychosocial and Academic Adjustment of Students in Universities in Lagos State

ERIC Educational Resources Information Center

Ohuakanwa, Chijioke Ephraim; Omeje, Joachim Chinweike; Eskay, Michael

2012-01-01

The study sought to investigate the relationship between pornography addiction and psychosocial and academic adjustment of students in universities in Lagos State. In order to achieve this objective, five research questions were formulated and two hypotheses postulated. The subjects for the study consisted of 616 full-time third-year undergraduate…

Facilities available for biomedical science research in the public universities in Lagos, Nigeria.

PubMed

John, T A

2010-03-01

Across the world, basic medical scientists and physician scientists work on common platforms in state-of-the-arts laboratories doing translational research that occasionally results in bedside application. Biotechnology industries capitalise on useful findings for colossal profit.1 In Nigeria and the rest of Africa, biomedical science has not thrived and the contribution of publications to global high impact journals is low.2 This work investigated facilities available for modern biomedical research in Lagos public universities to extract culprit factors. The two public universities in Lagos, Nigeria were investigated by a cross sectional questionnaire survey of the technical staff manning biomedical science departments. They were asked about availability of 47 modern biomedical science research laboratory components such as cold room and microscopes and six research administration components such as director of research and grants administration. For convenient basic laboratory components such as autoclaves and balances, 50% responses indicated "well maintained and always functional" whereas for less convenient complex, high maintenance, state-of-the-arts equipment 19% responses indicated "well maintained and always functional." Respondents indicated that components of modern biomedical science research administration were 44% of expectation. The survey reveal a deficit in state-of the-arts research equipment and also a deficit in high maintenance, expensive equipment indicating that biomedical science in the investigated environment lacks the momentum of global trends and also lacks buoyant funding. In addition, administration supporting biomedical science is below expectation and may also account for the low contributions of research articles to global high impact journals.

Response of patent medicine vendors in rural areas of Lagos state Nigeria to antimalarial policy change.

PubMed

Oyeyemi, Abisoye; Ogunnowo, Babatunde; Odukoya, Oluwakemi

2015-06-01

Patent medicine vendors (PMVs) play an important role in the treatment of malaria, especially in the rural areas. Nigeria recently changed her antimalarial treatment policy from chloroquine to artemisinin-based combination therapy (ACT). To determine the response of PMVs to the new policy. A baseline study was conducted in two local government areas (LGAs) of Lagos state Nigeria as the first phase in an intervention study aimed at improving the malarial treatment practices of PMVs in rural Lagos. A mixed method design involving a questionnaire survey of 180 PMVs and four key informant interviews were used. An antimalarial drug (AMD) audit was also performed. More than 80% of respondents were aware of the policy change in malaria treatment, but only 23.9% sold an ACT for the last case of malaria treated in an under five child. The main determining factor of the particular AMD sold was PMV's personal choice (70.6%). About half (58.9%) of the shops stocked ACTs, the newly recommended antimalarials. The high awareness of the policy change did not translate to a commensurate increase in the sale of the new drugs. Factors beyond the PMVs need to be addressed for a successful adoption of the new policy.

The Relevance of Multi Media Skills in Teaching and Learning of Scientific Concepts in Secondary Schools in Lagos State, Nigeria

ERIC Educational Resources Information Center

Okedeyi, Abiodun S.; Oginni, Aderonke M.; Adegorite, Solomon O.; Saibu, Sakibu O.

2015-01-01

This study investigated the relevance of multi media skills in teaching and learning of scientific concepts in secondary schools. Self constructed questionnaire was administered to 120 students randomly selected in four secondary schools in Ojo Local Government Area of Lagos state. Data generated were analyzed using chi-square statistical…

Fractionation and ecotoxicological implication of potentially toxic metals in sediments of three urban rivers and the Lagos Lagoon, Nigeria, West Africa.

PubMed

Oyeyiola, Aderonke O; Davidson, Christine M; Olayinka, Kehinde O; Alo, Babajide I

2014-11-01

The potential environmental impact of sediment-bound Cd, Cr, Cu, Pb and Zn in three trans-urban rivers in Lagos state and in the Lagos Lagoon was assessed by use of the modified Community Bureau of Reference (BCR) sequential extraction. The quality of the data was checked using BCR CRM 143R and BCR CRM 701. Good agreement was obtained between found and certified/indicative values. Of the rivers, the Odo-Iyaalaro, was generally the most contaminated and the Ibeshe the least. Higher concentrations of metals were generally found in the dry season compared to the wet season. Cadmium and Zn were released mostly in the acid exchangeable step of the sequential extraction, indicating that they have the greatest potential mobility and bioavailability of the analytes studied. Chromium and Cu were associated mainly with the reducible and oxidisable fractions, and Pb predominantly with the reducible and residual fractions. Sediments with the highest pseudototal analyte concentrations also released higher proportions of analytes earlier in the sequential extraction procedure. The study suggests that, during the dry season, potentially toxic metals (PTM) may accumulate in sediments in relatively labile forms that are released and can potentially be transported or bioaccumulate in the rainy season. Application of risk assessment codes and Hankanson potential risk indices indicated that Cd was the element of greatest concern in the Lagos Lagoon system. The study indicated that there is a need to strengthen environmental management and pollution control measures to reduce risk from PTM, but that even relatively simple strategies, such as seasonal restrictions on dredging and fishing, could be beneficial.

Ambulance services of lagos state, Nigeria: a six-year (2001-2006) audit.

PubMed

Adewole, O A; Fadeyibi, I O; Kayode, M O; Giwa, S O; Shoga, M O; Adejumo, A O; Ademiluyi, S A

2012-01-01

Emergency medical care is designed to overcome the factors most commonly implicated in preventable mortality, such as delays in seeking care, access to health facility, and the provision of adequate care at the facility. The developed world has recognized the importance of organized emergency medical services and has well established systems. The Lagos State Government established the first emergency medical system in Nigeria in 2001. This was to review the activities of the Lagos State Emergency Ambulance Services (LASAMBUS) within the stated period with the hope that our findings can be used to audit the system and make recommendations for further improvement. We reviewed the records of the State Ministry of Health for the data on the activities of LASAMBUS from 2001-2006. The number and types of emergencies that were seen and managed with the associated morbidity and mortality were reviewed. The constraints that were encountered by the LASAMBUS staff were also studied. The data that was obtained was entered into a proforma designed for the study. Analysis of the data was done using the Microsoft Excel software. A total of 32,774 cases comprising 21,977(67.1%) males,10,797(32.9%) females and a male to female (M:F) ratio of 2.04:1, were seen during the study period. Trauma was responsible for 29,500 (90%) of the cases. No mortality was recorded during the transfer of the cases. The records of mortality for the LASAMBUS-transferred cases were not available. Trauma cases formed the majority of the cases that were seen with road traffic accident constituting a large proportion of these. Health education focusing on improving driving etiquette of Drivers and injury prevention should intensified. More equipped emergency centres should be established to reduce victims transit and injuryintervention time. Record keeping and documentations should be improved for better assessment of the activities.

Comparing the knowledge, attitude and practices of health care workers in public and private primary care facilities in Lagos State on Ebola virus disease.

PubMed

Idris, Bilqisu Jibril; Inem, Victor; Balogun, Mobolanle

2015-01-01

The West African sub-region is currently witnessing an outbreak of EVD that began in December 2013. The first case in Nigeria was diagnosed in Lagos, at a private medical facility in July 2014. Health care workers are known amplifiers of the disease. The study aimed to determine and compare EVD knowledge, attitude and practices among HCWs in public and private primary care facilities in Lagos, Nigeria. This was a comparative cross-sectional study. Seventeen public and private primary care facilities were selected from the 3 senatorial districts that make up Lagos State. 388 respondents from these facilities were selected at random and interviewed using a structured questionnaire. Proportion of respondents with good knowledge and practice among public HCWs was 98.5% and 93.8%; and among private HCW, 95.9% and 89.7%. Proportion of respondents with positive attitude was 67% (public) and 72.7% (private). Overall, there were no statistically significant differences between the knowledge, attitude and preventive practices of public HCWs and that of private HCWs, (p≤0.05). Timely and intense social mobilization and awareness campaigns are the best tools to educate all segments of the community about public health emergencies. There exists significant surmountable gaps in EVD knowledge, negative attitude and sub-standard preventive practices that can be eliminated through continued training of HCW and provision of adequate material resources.

Comparing the knowledge, attitude and practices of health care workers in public and private primary care facilities in Lagos State on Ebola virus disease

PubMed Central

Idris, Bilqisu Jibril; Inem, Victor; Balogun, Mobolanle

2015-01-01

Introduction The West African sub-region is currently witnessing an outbreak of EVD that began in December 2013. The first case in Nigeria was diagnosed in Lagos, at a private medical facility in July 2014. Health care workers are known amplifiers of the disease. The study aimed to determine and compare EVD knowledge, attitude and practices among HCWs in public and private primary care facilities in Lagos, Nigeria. Methods This was a comparative cross-sectional study. Seventeen public and private primary care facilities were selected from the 3 senatorial districts that make up Lagos State. 388 respondents from these facilities were selected at random and interviewed using a structured questionnaire. Results Proportion of respondents with good knowledge and practice among public HCWs was 98.5% and 93.8%; and among private HCW, 95.9% and 89.7%. Proportion of respondents with positive attitude was 67% (public) and 72.7% (private). Overall, there were no statistically significant differences between the knowledge, attitude and preventive practices of public HCWs and that of private HCWs, (p≤0.05). Conclusion Timely and intense social mobilization and awareness campaigns are the best tools to educate all segments of the community about public health emergencies. There exists significant surmountable gaps in EVD knowledge, negative attitude and sub-standard preventive practices that can be eliminated through continued training of HCW and provision of adequate material resources. PMID:26740847

Precious metal-bearing epithermal deposits in western Patagonia (NE Lago Fontana region), Argentina

NASA Astrophysics Data System (ADS)

Lanfranchini, Mabel Elena; Etcheverry, Ricardo Oscar; de Barrio, Raúl Ernesto; Recio Hernández, Clemente

2013-04-01

Precious metal-bearing quartz veins occur at the northeastern sector of the Lago Fontana region in southwestern Argentina, within the context of the Andean continental magmatic arc environment. The deposits and their associated alteration zones are spatially related to a Cretaceous calc-alkaline magmatism represented by silicic dikes and hypabyssal intrusions, and hosted by a Late Jurassic to Cretaceous volcano-sedimentary sequence. The veins and related veinlets crop out discontinuously, in general terms in a NW-SE belt. The primary vein mineral assemblage is composed mostly of pyrite ± galena ± chalcopyrite > hematite ± arsenopyrite in silica gangue minerals. Chemical analyses of grab samples from selected quartz veins show as much as 5.7 ppm Au and 224 ppm Ag, as well as elevated Pb, Cu, and Zn. Hydrothermal fluids caused an innermost silicification and adularia-sericite alteration assemblage, and an external propylitic halo. Sulfur isotope values measured for sulfides (δSS from -1.90 to +1.56‰), and oxygen and hydrogen isotopes measured on quartz crystals and extracted primary fluid inclusion waters (δOO = -2.85 to +5.40‰; δDO = -106.0 to -103.4‰) indicate that mineralization probably formed from magmatic fluids, which were mixed with meteoric waters. Also, fluid inclusion data from quartz veins point out that these fluids had low salinity (1.7-4.2 wt% NaCl equiv.), and temperatures of homogenization between 180 and 325 °C. Mineralogical, petrographic and geochemical features for mineralized surface exposures indicate a typical adularia-sericite, low sulfidation epithermal system in the Lago Fontana area that represents a promising target for further exploration programs.

Contraception among bankers in an urban community in Lagos State, Nigeria.

PubMed

Meka, Ijeoma Angela; Okwara, Emmanuel Chidiebere; Meka, Anthony Obiamaka

2013-01-01

Contraception means procedures employed to interfere at one stage or the other with the normal sequence of events in the process of reproduction leading to a failure in conception. It means voluntary techniques adopted to achieve birth control. Its use remains sensitive worldwide. Within the same society, contraception varies amongst people of different socio-cultural, educational, religious, or occupational affiliations. It also varies between urban and rural settlements. Some contraceptive techniques also prevent sexually transmitted infections (STIs). The prevalence of STIs also varies with these same factors. There is very limited literature on contraception exclusively amongst bankers. We sought to investigate the level of awareness and practice of contraception amongst bankers in an urban society in Lagos State, Nigeria. In this descriptive cross-sectional study, 200 self-administered structured questionnaires were retrieved from bankers from 5 banks selected by simple random sampling in Surulere Local Government Area of Lagos State, Nigeria. Data was subsequently statistically analyzed using SPSS. The age range was 21-45 years, mean 28.8±1.4 years, 51.7% were males (72% single, 27% married, 1% separated) and 48.3% were females (52.4% single, 47.6% married). All (100%) respondents were aware of contraception, 93.3% males and 91.7% females were sexually active, 88.9% males and 84.5% females believe contraception is useful. Most (71.4%) respondents practice contraception, males (81%) being more than females (61.1%), p < 0.05. More (71.4%) females and fewer (37.8%) males believe that contraception prevents pregnancy but not STIs, 28.6% of females and 46.6% of males believe it prevents both pregnancy and STIs, whereas 14% of males and no female believe contraception prevents STIs but not pregnancy. The awareness of and practice of contraception was very high among the bankers but more male bankers practice contraception whereas more female bankers perceive

High prevalence of HIV, chlamydia and gonorrhoea among men who have sex with men and transgender women attending trusted community centres in Abuja and Lagos, Nigeria.

PubMed

Keshinro, Babajide; Crowell, Trevor A; Nowak, Rebecca G; Adebajo, Sylvia; Peel, Sheila; Gaydos, Charlotte A; Rodriguez-Hart, Cristina; Baral, Stefan D; Walsh, Melissa J; Njoku, Ogbonnaya S; Odeyemi, Sunday; Ngo-Ndomb, Teclaire; Blattner, William A; Robb, Merlin L; Charurat, Manhattan E; Ake, Julie

2016-01-01

Sexually transmitted infection (STI) and HIV prevalence have been reported to be higher amongst men who have sex with men (MSM) in Nigeria than in the general population. The objective of this study was to characterize the prevalence of HIV, chlamydia and gonorrhoea in this population using laboratory-based universal testing. TRUST/RV368 represents a cohort of MSM and transgender women (TGW) recruited at trusted community centres in Abuja and Lagos, Nigeria, using respondent-driven sampling (RDS). Participants undergo a structured comprehensive assessment of HIV-related risks and screening for anorectal and urogenital Chlamydia trachomatis and Neisseria gonorrhoeae , and HIV. Crude and RDS-weighted prevalence estimates with 95% confidence intervals (CIs) were calculated. Log-binomial regression was used to explore factors associated with prevalent HIV infection and STIs. From March 2013 to January 2016, 862 MSM and TGW (316 in Lagos and 546 in Abuja) underwent screening for HIV, chlamydia and gonorrhoea at study enrolment. Participants' median age was 24 years [interquartile range (IQR) 21-27]. One-third (34.2%) were identified as gay/homosexual and 65.2% as bisexual. The overall prevalence of HIV was 54.9%. After adjusting for the RDS recruitment method, HIV prevalence in Abuja was 43.5% (95% CI 37.3-49.6%) and in Lagos was 65.6% (95% CI 54.7-76.5%). The RDS-weighted prevalence of chlamydia was 17.0% (95% CI 11.8-22.3%) in Abuja and 18.3% (95% CI 11.1-25.4%) in Lagos. Chlamydia infection was detected only at the anorectal site in 70.2% of cases. The RDS-weighted prevalence of gonorrhoea was 19.1% (95% CI 14.6-23.5%) in Abuja and 25.8% (95% CI 17.1-34.6%) in Lagos. Overall, 84.2% of gonorrhoea cases presented with anorectal infection only. Over 95% of STI cases were asymptomatic. In a multivariable model, increased risk for chlamydia/gonorrhoea was associated with younger age, gay/homosexual sexual orientation and higher number of partners for receptive anal sex

Detection of toxigenic Clostridium perfringens and Clostridium botulinum from food sold in Lagos, Nigeria.

PubMed

Chukwu, Emelda E; Nwaokorie, Francisca O; Coker, Akitoye O; Avila-Campos, Mario J; Solis, Rosa L; Llanco, Luis A; Ogunsola, Folasade T

2016-12-01

Food-borne diseases contribute to the huge burden of sickness and death globally and in the last decade, have become more frequently reported in Africa. In line with this, food safety is becoming a significant and growing public health problem in Nigeria. Diarrhoea is a common problem in Nigeria and has been reported but there has been little data on the possibility of clostridia as aetiological agents. Clostridium species are ubiquitous in the environment and in the gastrointestinal tract of man and animals and can serve as a marker for faecal contamination. We set out to determine the potential of these foods to transmit Clostridium species. A total of 220 food commodities from six local governments in Lagos State were sampled. Isolates obtained were identified based on cultural, morphological and biochemical characteristics. Toxinotyping was done using multiplex-PCR with primers specific for alpha, beta, epsilon and iota-toxin genes, enterotoxigenic cpe gene and neurotoxigenic BoNt gene. Fifty (22.7%) clostridial species were isolated of which 29 (58%) were identified as C. perfringens. Toxinotyping of the 29 strains showed that 28 (96.6%) were toxin producing C. perfringens type A while one (3.4%) was C. perfringens type D. Two (4%) C. botulinum species were isolated and identified by 16S rRNA sequencing, both harbouring BoNt/A gene. The contamination rates of food with Clostridium species show that food hygiene is a problem and Clostridium species may be a source of food borne disease in Lagos State, Nigeria. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evidences of "Lago-Mare" episode around the Messinian-Pliocene boundary in eastern Tunisia (central Mediterranean)

NASA Astrophysics Data System (ADS)

Frigui, Mouna; Ben Youssef, Mohamed; Ouaja, Mohamed

2016-11-01

Eight stratigraphic sections, located in northeastern part of the Sahel area of Tunisia recorded evidences of "Lago-Mare" episode and events related to the Messinian-Late Pliocene interval. A comparison with previous studies carried on sections from neighboring areas and boreholes data drilled within the Gulf of Hammamet and the Gulf of Gabès, is conducted and gives useful information to characterize the Late Messinian to Late Pliocene events. The most notable feature distinguished in the studied area consists on the lack of gypsum, commonly recorded in relation with the crucial event of the Messinian Salinity Crisis. However, only lagoonal deposits, bearing messinian brackish fauna, are encountered. These sediments are usually attributed to the "Segui" formation or the so called "Mio-Pliocene continental". Thin sections samples and field observations have recognized sands, marls, clays, lacustrine limestone, some gypsum lenses, mud-cracks, lignite and Messinian brackish fauna. Similar deposits were previously described in the Kechabta basin from the Northern Tunisia and in some wells from the Gulf of Gabès and the Gulf of Hammamet. We suggest that all these facies belong to the coeval of the "Lago-Mare" facies within Eastern and Western Mediterranean basins (e.g. Sicily, Mallorca, Libya and Cyprus). Finally, four major erosional surfaces have been recorded within the Late Messinian-Late Pliocene deposits, aged post-Tortonian, intra-Messinian, Late Messinian and intra-Pliocene times. They seem to be the result of local tectonic uplifts and eustatic fluctuations.

Workability of Safety Education and Training for Workers' Strategy in Accident Reduction in Selected Manufacturing Industries in Lagos State

ERIC Educational Resources Information Center

Ayodele, Rachael B.; Olubayo-Fatiregun, Martina A.

2013-01-01

This study determined the workability of Safety Education and Training for Workers' strategy in reducing accidents. A descriptive survey research design was used. A total of 20 Managerial staff with mean work experience of 13.5 years was selected from 10 manufacturing industries in Lagos State, using intact group method. They were 100% males. Data…

Knowledge and use of dietary supplements by students of College of Medicine, University of Lagos, Idi-Araba, Lagos, Nigeria

PubMed Central

Aina, Bolajoko A.; Ojedokun, Oluwayemisi A.

2014-01-01

Rationale: Nutritional supplements are preparations intended to supplement the diet and provide nutrients. They include vitamins, minerals, fiber, fatty acids, or amino acids, that may be missing or may not be consumed in sufficient quantities in a person's diet. Many health professionals including dietitians, physicians and pharmacists are supplement users. Objectives: The objectives of the present study were to determine knowledge and use of dietary supplements among students of College of Medicine, University of Lagos who are potential health professionals. Methodology: A self-administered questionnaire with a mix of open and close ended questions was employed to collect data in this study. It was distributed to 300 students that were in their final year in various departments of the college. Findings: Response rate was 89%. About 86% of the students have used dietary supplement before while half of them (50%) have used it in the past 12 months. The common types of dietary supplements used in the past 12 months are the vitamins. The reasons for use by the students were good health, poor diet, to boost immunity, weight gain and doctor's prescription. Most of the students were occasional and once in a while users. Conclusions: Majority of the students were aware of dietary supplement use and most of them were occasional users. PMID:25031497

Yield per recruit of the peacock bass Cichla monoculus (Spix and Agassiz, 1831) caught in Lago Grande at Manacapuru (Amazonas - Brazil).

PubMed

Campos, C P; Freitas, C E C

2014-02-01

We evaluated the stock of peacock bass Cichla monoculus caught by a small-scale fishing fleet in Lago Grande at Manacapuru. The database was constructed by monthly samplings of 200 fish between February 2007 and January 2008. We measured the total length (cm) and total weight (gr) of each fish. We employed previously estimated growth parameters to run a yield per recruit model and analyse scenarios changing the values of the age of the first catch (Tc), natural mortality (M), and fishing mortality (F). Our model indicated an occurrence of overfishing because the fishing effort applied to catch peacock in Lago Grande at Manacapuru is greater than that associated with the maximum sustainable yield. In addition, the actual size of the first catch is almost half of the estimated value. Although there are difficulties in enforcing a minimum size of the catch, our results show that an increase in the size of the first catch to at least 25 cm would be a good strategy for management of this fishery.

High prevalence of HIV, chlamydia and gonorrhoea among men who have sex with men and transgender women attending trusted community centres in Abuja and Lagos, Nigeria

PubMed Central

Keshinro, Babajide; Crowell, Trevor A; Nowak, Rebecca G; Adebajo, Sylvia; Peel, Sheila; Gaydos, Charlotte A; Rodriguez-Hart, Cristina; Baral, Stefan D; Walsh, Melissa J; Njoku, Ogbonnaya S; Odeyemi, Sunday; Ngo-Ndomb, Teclaire; Blattner, William A; Robb, Merlin L; Charurat, Manhattan E; Ake, Julie

2016-01-01

Introduction Sexually transmitted infection (STI) and HIV prevalence have been reported to be higher amongst men who have sex with men (MSM) in Nigeria than in the general population. The objective of this study was to characterize the prevalence of HIV, chlamydia and gonorrhoea in this population using laboratory-based universal testing. Methods TRUST/RV368 represents a cohort of MSM and transgender women (TGW) recruited at trusted community centres in Abuja and Lagos, Nigeria, using respondent-driven sampling (RDS). Participants undergo a structured comprehensive assessment of HIV-related risks and screening for anorectal and urogenital Chlamydia trachomatis and Neisseria gonorrhoeae, and HIV. Crude and RDS-weighted prevalence estimates with 95% confidence intervals (CIs) were calculated. Log-binomial regression was used to explore factors associated with prevalent HIV infection and STIs. Results From March 2013 to January 2016, 862 MSM and TGW (316 in Lagos and 546 in Abuja) underwent screening for HIV, chlamydia and gonorrhoea at study enrolment. Participants’ median age was 24 years [interquartile range (IQR) 21–27]. One-third (34.2%) were identified as gay/homosexual and 65.2% as bisexual. The overall prevalence of HIV was 54.9%. After adjusting for the RDS recruitment method, HIV prevalence in Abuja was 43.5% (95% CI 37.3–49.6%) and in Lagos was 65.6% (95% CI 54.7–76.5%). The RDS-weighted prevalence of chlamydia was 17.0% (95% CI 11.8–22.3%) in Abuja and 18.3% (95% CI 11.1–25.4%) in Lagos. Chlamydia infection was detected only at the anorectal site in 70.2% of cases. The RDS-weighted prevalence of gonorrhoea was 19.1% (95% CI 14.6–23.5%) in Abuja and 25.8% (95% CI 17.1–34.6%) in Lagos. Overall, 84.2% of gonorrhoea cases presented with anorectal infection only. Over 95% of STI cases were asymptomatic. In a multivariable model, increased risk for chlamydia/gonorrhoea was associated with younger age, gay/homosexual sexual orientation and higher

Cost implication of irrational prescribing of chloroquine in Lagos State general hospitals.

PubMed

Aina, Bolajoko A; Tayo, Fola; Taylor, Ogori

2008-02-01

A major share of the hospital budget is spent on drugs. Irrational use of these drugs is a waste of financial and human resources that could have been deployed for another use within the hospital setting especially in cases where such drugs are provided free to patients. Also there is increased morbidity and progression of severity with irrational use. The objective of this study was to determine the irrational use of chloroquine and the subsequent cost implications in Lagos State general hospitals. A retrospective study period of one year (January to December, 2000) was selected. A total of 18,781 prescription forms of "Free Eko Malaria" were sampled for children and adults from all the Lagos State general hospitals. Drug costs in each prescription form were identified. Cost effectiveness analysis of chloroquine tablet and intramuscular injection was undertaken. The average cost of medicine per prescription was 132.071 ($1.03) which should have been 94.22 ($0.73) if prescribed rationally. The total cost of prescriptions for malaria under study was 2,480,425.00 ($19,348.09). About 68% {(1,679,444.00) ($13,100.19)} of the total cost was lost to irrational prescribing. This is a waste of scarce resources. When the prescriptions were differentiated into the different dosage forms prescribed, the prescriptions containing intramuscular injections only had over 90% of the cost lost to irrational prescribing. Cost effectiveness analysis showed that chloroquine tablet was 17 times more cost effective than chloroquine injection (intramuscular) from a health care system perspective while it was 14 times more cost effective from a patient perspective. There is waste of scarce resources with irrational dispensing of drugs and these resources could have been deployed to other uses or areas within the hospitals. The tablet chloroquine was more cost effective than injection chloroquine (intramuscular). Increasing the cost of tablets, decreasing effectiveness of tablets

Ocular findings in acquired immunodeficiency syndrome patients in Lagos, Nigeria.

PubMed

Onakoya, A O; Odeyemi, M G; Aribaba, O T; Akinsola, F B

2012-01-01

There is paucity of studies on the prevalence and pattern of ocular complication in HIV patients in developing countries where 90% of all HIV sufferers live. Most studies were carried out in industrialized countries and are not representative of the spectrum of ocular complication of HIV and it's prevalence in developing countries. To determine the prevalence of ocular disorders in adult (> 15 years ) AIDS patients at PEPFAR clinic in Lagos, Nigeria. All consecutive adult Seropositive HIV/AIDS patients of PEPFAR Clinic at the Lagos University Teaching Hospital between February 1st-March 15th 2008 were enrolled into the study Cross sectional and non randomized, convenient study was used. Biodata and medical history were recorded on interviewer administered questionnaire. Participants were examined according to standard protocol comprising visual acuity, intraocular pressure, anterior segment examination with slit lamp biomicroscopy, dilated fundoscopy and fundus photograph where necessary. PCV, CD4+ count, viral load at diagnosis, stage of HIV disease were extracted from patients' records. Details of drug were regimen also recorded. Data analysis was performed with EPI-lnfo 6.04 version; Chi square and student t test used to describe statistical association. A total of 400 patients were studied. Male:female ratio was 1.7 and mean age was 40 years (S.D. + 9.12). Ocular disorders seen in 78.5% of patients; HIV related ocular disorders occurred in 45 (11.3) patients. Conjunctival microvasculopathy 166 patients (41.5%), pingueculum in 114 (28.5%), pterygium in 76 (19.0%), refractive error in 93 (23.3%), cataract in 12 (3.0%), and 22 (5.5%) Glaucoma suspects. HIV retinopathy and allergic eye disease in one patient each (0.3%). Presumed Cytomegalovirus retinitis 7 (1.8%), 14 (3.5%) Toxoplasmosis, 8 (2.0%) HZO, and 15 (3.8%) Presumed Squamous cell carcinoma. Eighty six (21.5%) of the patients had no abnormality. 91.4% of eyes examined had visual acuity with best correction

Clinicopathologic review of polyps biopsied at colonoscopy in Lagos, Nigeria.

PubMed

Oluyemi, Aderemi; Awolola, Nicholas; Oyedeji, Olufemi

2016-01-01

Colorectal polyps are known precursors of colorectal cancers. The increase in utilization of colonoscopy in Nigeria has meant a rise in the recently reported incidence of these lesions. The aim of this study is to evaluate the clinicopathological profile of colorectal polyps biopsied during the inaugural 12 month period of colonoscopy from a private endoscopy suite in Nigeria. This is a retrospective review of all the clients who had polyps diagnosed at colonoscopy over a 12 month period (August 2014 -July 2015) at a private endoscopy suite in Lagos, Nigeria. This analysis of prospectively collected data was performed using clinical information from the endoscopy logs and pathology database system of a private endoscopy suite based in Lagos, Nigeria. A total of 125 colonoscopies were carried out over the stated period. Of these, 14 individuals had a total of 18 polyps- 4 clients (28.6% of the persons with polyps) had two polyps each. The polyp detection rate was 11.2% while the polyp per colonoscopy rate was 14.4%. Of these clients, males were 10 in number; giving a male to female ratio of 2.5:1. Their ages ranged from 37 to 77 years (mean= 57.3 years). The presenting complaint at colonoscopy was hematochezia in 11 (78.6%), new onset constipation in 2 (14.2%) and peri-anal pain in 1 patient (7.1%). The polyps were distributed as follows; 2 (11.1%) in the ascending colon, 1 (5.6%) each in the transverse and descending colons, 8 (44.4%) in the sigmoid colon, 6(33.3%) located in the rectum. Hence, there was left sided (15 of 18= 83.3%) preponderance. Pathologically, tubular (adenomatous) polyp with or without low grade dysplastic changes was diagnosed in 6 of the 18 polyps (giving an adenoma detection rate of 4.8%), 4 (22.2%) were inflammatory polyps, 1 (5.6%) was malignant and another had the rare inflammatory fibroid polyp. Five (27.8%) of the specimens were reported as non-specific colitis. The study supports the present wisdom that polyps are clearly less

Rock magnetic and geochemical proxies for iron mineral diagenesis in a tropical lake: Lago Verde, Los Tuxtlas, East Central Mexico

NASA Astrophysics Data System (ADS)

Ortega, Beatriz; Caballero, Margarita; Lozano, Socorro; Vilaclara, Gloria; Rodríguez, Alejandro

2006-10-01

Magnetic and non-magnetic mineral analyses were conducted on a lacustrine sequence from Lago Verde in the tropical coast along the Gulf of Mexico that covers the last 2000 years. The site witnessed the transformation of the environment since the early Olmec societies until forest clearance in the last century. Through these analyses we investigated the processes that affected the magnetic mineralogy in order to construct a model of past environmental changes, and compare this model with the archeological record and inferred climatic changes in the northern hemisphere of tropical America. Volcanic activity has played a major influence on sediment magnetic properties, as a purveyor of Ti-magnetites/Ti-maghemites, and as a factor of instability in the environment. Anoxic reductive conditions are evident in most of Lago Verde's sedimentary record. Direct observations of magnetic minerals and ratios of geochemical (Fe, Ti), and ferrimagnetic ( χf) and paramagnetic ( χp) susceptibility ( χ) data, are used as parameters for magnetite dissolution ( χp/ χ, Fe/ χf), and precipitation ( χf/Ti) of magnetic minerals. Intense volcanic activity and anoxia are recorded before A.D. 20, leading to the formation of framboidal pyrite. Increased erosion, higher evaporation rates, lower lake levels, anoxia and reductive diagenesis in non-sulphidic conditions are inferred for laminated sediments between A.D. 20-850. This deposit matches the period of historical crisis and multiyear droughts that contributed to the collapse of the Maya civilization. Dissolution of magnetite, a high organic content and framboidal pyrite point to anoxic, sulphidic conditions and higher lake levels after A.D. 850. Higher lake levels in Lago Verde broadly coincide with the increased precipitation documented during the Medieval Warm Period (A.D. 950-1350) in the northern tropical and subtropical regions of the American continent. For the Little Ice Age (A.D. 1400-1800), the relatively moist conditions

Neurodevelopmental delay among children under the age of three years at immunization clinics in Lagos State, Nigeria - Preliminary report.

PubMed

Bakare, Muideen O; Bello-Mojeed, Mashudat A; Munir, Kerim M; Ogun, Oluwayemi C; Eaton, Julian

2016-04-29

Late diagnosis and interventions characterize childhood neurodevelopmental disorders in Sub-Saharan Africa. This has negatively impacted on the prognosis of the children with neurodevelopmental disorders. This study examined the prevalence and pattern of neurodevelopmental delays among children under the age of 3 years attending immunization clinics in Lagos State, Nigeria and also affords opportunity of early follow-up and interventions, which had been documented to improve prognosis. The study involved two stage assessments; which consisted of first phase screening of the children for neurodevelopmental delays in immunization clinics at primary healthcare centers Lagos State, Nigeria and second phase which consists of definitive clinical evaluation and follow-up interventions for children screened positive for neurodevelopmental delays. Twenty seven (0.9%) of a total of 3,011 children under the age of 3 years were screened positive for neurodevelopmental delays and subsequently undergoing clinical evaluation and follow-up interventions. Preliminary working diagnoses among these children include cerebral palsy, autism spectrum disorder trait, nutritional deficiency, Down syndrome and Non-specific neurodevelopmental delay with co-morbid seizure disorder accounting for 33.3%, 14.8%, 18.5%, 7.4% and 25.9% respectively. This is a preliminary report that would be followed up with information on medium and long term intervention phase.

Comparative assessment of blood lead levels of automobile technicians in organised and roadside garages in Lagos, Nigeria.

PubMed

Saliu, Abdulsalam; Adebayo, Onajole; Kofoworola, Odeyemi; Babatunde, Ogunowo; Ismail, Abdussalam

2015-01-01

Occupational exposure to lead is common among automobile technicians and constitutes 0.9% of total global health burden with a majority of cases in developing countries. The aim of this study was to determine and compare the blood lead levels of automobile technicians in roadside and organised garages in Lagos State, Nigeria. This was a comparative cross-sectional study. Data were collected using interviewer-administered questionnaires. Physical examinations were conducted and blood was analysed for lead using atomic spectrophotometery. Statistical analyses were performed to compare the median blood lead levels of each group using the independent sample (Mann-Whitney U) test. Seventy-three (40.3%) of the organised compared to 59 (34.3%) of the roadside groups had high blood lead levels. The organised group had statistically significant higher median blood lead levels of, 66.0 µg/dL than the roadside 43.5 µg/dL (P < 0.05). There was also statistically significant association between high blood lead levels and abnormal discolouration of the mucosa of the mouth in the organised group. Automobile technicians in organised garages in Lagos have higher prevalence of elevated blood lead levels and higher median levels than the roadside group. Preventive strategies against lead exposures should be instituted by the employers and further actions should be taken to minimize exposures, improve work practices, implement engineering controls (e.g., proper ventilation), and ensure the use of personal protective equipment.

Comparative Assessment of Blood Lead Levels of Automobile Technicians in Organised and Roadside Garages in Lagos, Nigeria

PubMed Central

Saliu, Abdulsalam; Adebayo, Onajole; Kofoworola, Odeyemi; Babatunde, Ogunowo; Ismail, Abdussalam

2015-01-01

Occupational exposure to lead is common among automobile technicians and constitutes 0.9% of total global health burden with a majority of cases in developing countries. The aim of this study was to determine and compare the blood lead levels of automobile technicians in roadside and organised garages in Lagos State, Nigeria. This was a comparative cross-sectional study. Data were collected using interviewer-administered questionnaires. Physical examinations were conducted and blood was analysed for lead using atomic spectrophotometery. Statistical analyses were performed to compare the median blood lead levels of each group using the independent sample (Mann-Whitney U) test. Seventy-three (40.3%) of the organised compared to 59 (34.3%) of the roadside groups had high blood lead levels. The organised group had statistically significant higher median blood lead levels of, 66.0 µg/dL than the roadside 43.5 µg/dL (P < 0.05). There was also statistically significant association between high blood lead levels and abnormal discolouration of the mucosa of the mouth in the organised group. Automobile technicians in organised garages in Lagos have higher prevalence of elevated blood lead levels and higher median levels than the roadside group. Preventive strategies against lead exposures should be instituted by the employers and further actions should be taken to minimize exposures, improve work practices, implement engineering controls (e.g., proper ventilation), and ensure the use of personal protective equipment. PMID:25759723

The direct hospitalization cost of care for acute burns in Lagos, Nigeria: a one-year prospective study

PubMed Central

Ahachi, C.N.; Fadeyibi, I.O.; Abikoye, F.O.; Chira, M.K.; Ugburo, A.O.; Ademiluyi, S.A.

2011-01-01

Summary Objective. We conducted a prospective study to identify the direct hospitalization cost of managing major acute burns in Lagos, Nigeria, and to determine the factors that influence the cost. Method. All consecutive and consenting patients seen and managed for major burns at the National Orthopaedic Hospital, Igbobi, Lagos, between 1 June 2007 and 31 May 2008 were recruited for the study. A special form designed for the study was used to collect the necessary data. Results. Fifty-two patients were seen during the study period (27 males and 25 females). The ages ranged from 2 months to 69 yr with a mean of 25.4 ± 17.1 yr. The length of hospital stay ranged from 0.3-12 months (mean, 3.2 ± 3.1 months). The average daily cost of treating a patient was ₦ (naira) 8,855 (₦1000 = €4.44) and the average overall cost was ₦209,303.70, with the costs of wound dressings, hospital admission, and surgery constituting respectively 29.5%, 25.7%, and 19.1% of the total amount spent. Conclusion. The length of hospital stay was prolonged in many patients and management methods should be reviewed to reduce this. The cost of managing burns is prohibitive for an average Nigerian. Efforts should be intensified to prevent burn injury and a Special Health Insurance policy should be established to finance burns management. PMID:22262967

Changes in the prevalence of dental caries in primary school children in Lagos State, Nigeria.

PubMed

Sofola, O O; Folayan, M O; Oginni, A B

2014-01-01

To evaluate the changes in the prevalence of dental caries in Lagos State over a 3 years period and the role of age, sex, and playing in the changes observed. Three primary schools in Lagos State, Nigeria were randomly selected for the study. Six hundred and thirty-three children age 2-12 years, were examined for caries in 2000 while 513 children were examined in 2003. The prevalence of tooth decay and the prevalence of untreated tooth decay were calculated for the two years, that is, 2000 and 2003. Also the degree of unmet treatment need among the population with caries experience was measured. Differences in the prevalence and severity of dental caries in the primary and permanent dentition were assessed. Approximately 18% of children had untreated tooth decay in their primary dentition in 2003: A 26.1% increase from 2000. About 12.0% of the decay, extracted, and filled teeth (deft) index was seen with decayed teeth in 2000 and 16.6% in 2003. Extracted primary teeth decreased from 2.5% in 2000 to 1.5% in 2003. The change in mean deft between 2000 (0.42) and 2003 (0.47) was 11.9%. Over the study period, the overall reduction in the prevalence of dental caries was 34.8% in the permanent dentition. The decline was larger among children aged 5-9 years (62.1%) and among females (75%). The study showed no overall changes in caries severity but a decrease in caries prevalence in the permanent dentition over the study period. The largest decline in caries prevalence in the permanent dentition was observed in children aged 5-9 years and females. On the contrary, there was an increase in the caries prevalence in the primary dentition.

First evidence of "paralytic shellfish toxins" and cylindrospermopsin in a Mexican freshwater system, Lago Catemaco, and apparent bioaccumulation of the toxins in "tegogolo" snails (Pomacea patula catemacensis).

PubMed

Berry, John P; Lind, Owen

2010-05-01

Exposure to cyanobacterial toxins in freshwater systems, including both direct (e.g., drinking water) and indirect (e.g., bioaccumulation in food webs) routes, is emerging as a potentially significant threat to human health. We investigated cyanobacterial toxins, specifically cylindrospermopsin (CYN), the microcystins (MCYST) and the "paralytic shellfish toxins" (PST), in Lago Catemaco (Veracruz, Mexico). Lago Catemaco is a tropical lake dominated by Cylindrospermopsis, specifically identified as Cylindrospermopsis catemaco and Cylindrospermopsis philippinensis, and characterized by an abundant, endemic species of snail (Pomacea patula catemacensis), known as "tegogolos," that is both consumed locally and commercially important. Samples of water, including dissolved and particulate fractions, as well as extracts of tegogolos, were screened using highly specific and sensitive ELISA. ELISA identified CYN and PST at low concentrations in only one sample of seston; however, both toxins were detected at appreciable quantities in tegogolos. Calculated bioaccumulation factors (BAF) support bioaccumulation of both toxins in tegogolos. The presence of CYN in the phytoplankton was further confirmed by HPLC-UV and LC-MS, following concentration and extraction of algal cells, but the toxin could not be confirmed by these methods in tegogolos. These data represent the first published evidence for CYN and the PST in Lago Catemaco and, indeed, for any freshwater system in Mexico. Identification of the apparent bioaccumulation of these toxins in tegogolos may suggest the need to further our understanding of the transfer of cyanobacterial toxins in freshwater food webs as it relates to human health. Copyright 2009 Elsevier Ltd. All rights reserved.

EFFECT OF TRIMETHOPRIM-SULFAMETHOXAZOLE PROPHYLAXIS ON FAECAL CARRIAGE RATES OF RESISTANT ISOLATES OF ESCHERICHIA COLI IN HIV-INFECTED ADULT PATIENTS IN LAGOS.

PubMed

Egwuatu, C C; Iwuafor, A A; Egwuatu, T O; Akujobi, C N; Nnachi, A U; Aghanya, I N; Ogunsola, F T; Oduyebo, O O

2016-01-01

The daily use of Trimethoprim-Sulfamethoxazole (TMP-SMX) prophylaxis reduces morbidity and mortality among patients infected with Human Immunodeficiency Virus (HIV) but its impact on increasing antimicrobial resistance rates has been of public concern globally. This study investigated the effect of daily TMP-SMX prophylaxis on faecal carriage rates of resistant isolates of Escherichia coli in HIV-infected adult patients in Lagos. A total of 550 HIV-infected patients with CD4-cell count of less than 350 cell/mm 3 and were eligible for TMP-SMX prophylaxis attending Lagos University Teaching Hospital, Lagos, Nigeria, were recruited. Stool/rectal swab samples were aseptically collected from the patients and processed using standard methods for culture and sensitivity. There was a baseline Trimethoprim-Sulfamethoxazole resistance rate of 54% which increased to 77.9% in first 3 months, rising to 96.1% by 6 months and all isolates were resistant by the 9th month. There was also evidence of cross-resistance to other antibiotics with significant association with TMP-SMX resistance (p<0.0001). The Escherichia coli isolates showed a progressive increase in resistance to the tested antibiotics over the 12-month period. The resistance was in the following order: Ampicillin (74% to 82.6% in the first 3 months; 98.3% by the 6th month and 99.4% by the 9th month; all isolates were resistant by the 12th month). Augmentin (32.5% to 47.7% in first 3 months; 76.1% by the 6th month; 86.3% by the 9th month; all isolates were resistant by 12 months). Ceftriaxone (2.0% to 10.8% in first 3 months; 20.6% by the 6th month; 24.2% by the 9th month; 54.3% by the 12 months). The carriage rate of faecal E. coli resistant to TMP-SMX is common before TMP-SMX prophylaxis. Initiation of TMP-SMX leads to further increase in resistance to TMP-SMX and cross-resistance to other antimicrobials.

A Science Centre as a Geoturism promoter - the Lagos Ciência Viva examples (Portugal).

NASA Astrophysics Data System (ADS)

Azevedo Rodrigues, Luis; Leote, Catarina

2017-04-01

Science outreach and engagement are crucial core objectives of the Lagos Ciência Viva Science Centre (CCVL). By engaging audiences in the real world a link is made between their science centre experience and the environment in which they live. Therefore, it has been an option of the CCVL to offer geological outdoor activities, both in the natural environment and urban context. Dinosaurs are an appealing science subject for both students and tourists. Thus, the CCVL has a long tradition in organizing and guiding field trips to two dinosaur track sites - Salema and Santa beaches (Vila do Bispo, southwest Algarve). These sites, both from the Lower Cretaceous reveal at least two types of tracks - theropod and iguanodontian footprints. Often in combination with the paleontology field trips, the CCVL also offers different geological field trips both for formal (school) and informal (tourism) education. This allows students and tourists to be introduced to dinosaur paleobiology and ichnology and to the structural geology and stratigraphy of the area. Our science outreach is being further developed by contractual agreement with a regional tour operator, in which the CCVL is responsible for the scientific content and guidance of the visits. Aiming at an urban context, the CCVL produced three Urban Geology and Paleontology Guide Books for three Algarve cities (Lagos, Faro and Tavira), which can be acquired in the three Ciência Viva Science Centres shops as well as in the tourist information offices serving this way as a basis for guided urban tours also offered by the CCVL. Based on our experience, we review and contextualise these geoscience activities and their potential for science outreach, communication and tourism. We discuss and propose a classification of different possibilities in geoscience communication and outreach based on three vertices: Science, Heritage and Geotourism. Some particularities of these visits, such as the merge between geosciences and other

Mass Burns Disaster in Abule-egba, Lagos, Nigeria from a Petroleum Pipeline Explosion Fire

PubMed Central

Fadeyibi, I.O.; Omosebi, D.T.; Jewo, P.I.; Ademiluyi, S.A.

2009-01-01

Summary The aim of this paper is to review the basic principles of triage in mass burns disasters and discuss the experience of the Lagos State University Teaching Hospital (LASUTH), Ikeja, Nigeria, in the December 2006 disaster at Abule-Egba, Lagos, Nigeria. It is hoped that the experience gained will help in the planning for and management of similar disasters in the developing countries with limited facilities. Burn injury has been described as the severest form of trauma and its management is very challenging as it is often accompanied by numerous pathophysiological changes. Successful management requires expert management by well-trained personnel in equipped and dedicated centres. In mass disasters the total number of victims may exceed the capability of the facility and its staff and a system for sorting out the patients and caring for those that will benefit from the facilities available needs to be developed. Other patients will either be sent to other medical facilities for further treatment or discharged after initial care for future follow-up. Documented experiences in the management of mass burns disasters from petroleum pipeline explosions from developing countries are rare. However, petroleum pipeline explosions, especially in the Lagos area of Nigeria, are relatively common. These cases have been associated with a variety of factors. The resulting morbidity and mortality have been high. LASUTH has a dedicated burns centre, which has received and managed many burn patients. Triage is the medical process of screening patients according to their need of treatment and the resources available. The aims and objectives of triage are discussed, its various levels described, and the final goals elaborated. All the burn victims involved in the 2006 disaster were studied, together with the triage carried out at different levels and the consequent sorting of the patients. Standard burns management was carried out. A total of 385 patients sustained burns of

Potential health risks due to telecommunications radiofrequency radiation exposures in Lagos State Nigeria.

PubMed

Aweda, M A; Ajekigbe, A T; Ibitoye, A Z; Evwhierhurhoma, B O; Eletu, O B

2009-01-01

The global system mobile telecommunications system (GSM) which was recently introduced in Nigeria is now being used by over 40 million people in Nigeria. The use of GSM is accompanied with exposure of the users to radiofrequency radiation (RFR), which if significant, may produce health hazards. This is the reason why many relevant national and international organizations recommended exposure limits to RFR and why it is made compulsory for GSM handsets to indicate the maximum power output as a guide to potential consumers. This study was conducted to measure the RFR output power densities (S) from the most commonly used GSM handsets used in Lagos State and compare with the limit recommended for safety assessment. Over 1100 most commonly used handsets of different makes and models as well as wireless phones were sampled and studied in all over the local government areas of the State. An RFR meter, Electrosmog from LESSEMF USA was used for the measurements. The handsets were assessed for health risks using the reference value of 9 Wm(-2) as recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The range of the S-values obtained varied from a minimum of 1.294 0.101 Wm(-2) with Siemens model R228 to a maximum of 16.813 +/- 0.094 Wm(-2) with Samsung model C140*. The results from wireless telephones showed very low S-values ranging from a minimum of 0.024 +/- 0.001 Wm(-2) with HUAWEI and ST CDMA 1 to a maximum of 0.093 +/- 0.002 Wm(-2) with HISENSE. The results showed that the population in Lagos State may be at risk due to significant RFR exposures resulting principally from the use of GSM. Quite a number of handsets emit power above the ICNIRP recommended value. Measured RFR power close to Radio and Television masts and transmitters are within tolerable limits in most cases, only that the public should not reside or work close to RFR installations. Phone calls with GSM should be restricted to essential ones while youths and children

A Late Holocene Record of Human Impact in the Tropical Lowlands of the Mexican Gulf Coast: Lago Verde.

NASA Astrophysics Data System (ADS)

Socorro, L.; Sosa, S.; Caballero, M.; Rodriguez, A.; Ortega, B.

2005-05-01

Lago Verde is a maar lake (18 36 43 N; 95 20 52 W) located on the Gulf Coast of Mexico in "Los Tuxtlas" region. The area was cover by tropical rain forest and is part of the core area of the earliest Mesoamerican cultures. A 6 m sediment core was obtained in order to document vegetation and lake level history of this area. Lago Verde is a shallow, eutrophic lake (max. 4 m), the natural vegetation has been removed and grasslands with some tropical trees such Bursera grows around the lake. According with the radiocarbon chronology the sequence covers the last 2500 yr BP. At the base of the sequence low abundance of tropical trees is record, with intermediate lake levels. A sudden change in the pollen stratigraphy occurs at ca. 2000 yr BP, with important presence of Poaceae, Ambrosia and Cheno.-Am. along with Zea mays indicating human activity in the area. This is associated with a change in limnological conditions, recording turbid, shallow environments. This pollen signals correlates with dry phases in Yucatan, suggesting that this dry climatic signal probably had effect on an ample area of Mexico. However, at 1200 yr BP, no more Zea mays pollen is recovered suggesting the abandonment of the area. Lake levels recover as well as the tropical forest. The last 150 yr BP is characterized by the reduction in the pollen of tropical forest trees, presence of Zea mays, increased erosion rates, turbidity and eutrophication in the lake, all related to deforestation.

Is there a step-wise migration in Nigeria? A case study of the migrational histories of migrants in Lagos.

PubMed

Afolayan, A A

1985-09-01

"The paper sets out to test whether or not the movement pattern of people in Nigeria is step-wise. It examines the spatial order in the country and the movement pattern of people. It then analyzes the survey data and tests for the validity of step-wise migration in the country. The findings show that step-wise migration cannot adequately describe all the patterns observed." The presence of large-scale circulatory migration between rural and urban areas is noted. Ways to decrease the pressure on Lagos by developing intermediate urban areas are considered. excerpt

Data of the properties of rebar steel brands in Lagos, Nigerian market used in reinforced concrete applications.

PubMed

Joshua, Opeyemi; Olusola, Kolapo O; Oyeyemi, Kehinde D; Ogunde, Ayodeji O; Amusan, Lekan M; Nduka, David O; Abuka-Joshua, Joyce

2018-04-01

The data presented herein are compilations of the research summary of "Assessment of the Quality of Steel Reinforcement Bars Available in Nigerian Market" (Joshua et al., 2013) [1]. This data article provides information on the properties and cost of steel rebars used in reinforced concrete in Lagos, Nigeria. The data is based on the properties of 12 mm rebar brands which are the most used steel diameter in construction and they include actual diameters, yield strengths, ultimate strengths, ultimate/yield strength ratio, ductility and the cost of each brand. This data also contains the limiting standard properties of the highlighted properties in this data.

Use of CD-ROM MEDLINE by medical students of the College of Medicine, University of Lagos, Nigeria.

PubMed

Ogunyade, Taiwo O; Oyibo, Wellington A

2003-01-01

Use of information technology in information acquisition, especially MEDLINE on CD-ROM and online, has been evaluated in several localities and regions, especially in the advanced countries. Use of MEDLINE on CD-ROM is still very poor among the medical students of the University of Lagos, Lagos, Nigeria, due to lack of awareness, insufficient personal computers, nonperiodic training, and the high cost of using the facility. Due to financial constraints, MEDLINE online and sufficiently-networked computer systems are not available. To report on the situation in Nigeria, a developing country, so as to compare the current awareness of searching MEDLINE on CD-ROM among the medical students at the University of Lagos with the awareness of their overseas' counterparts. This is the first step toward setting up an online PubMed search as well as expanding the computer systems and network. Essentially based on cross-sectional proportional sampling using structured questionnaires, in-depth interviews, and focus-group discussions among the medical students and library staff. The study involved the medical students in their second year to sixth (final) year of study. Of the 250 students interviewed, 130 (52%) were aware of MEDLINE on CD-ROM searches as a means of information retrieval. Only 60 (24%) had used MEDLINE on CD-ROM-2% had used MEDLINE on CD-ROM more than 9 times; 4%, 7 to 9 times; 8%, 4 to 6 times; and 10%, 1 to 3 times. Of the students who used MEDLINE on CD-ROM search, 22% used it in preparing for examinations, 24% in research, 6% in patient care, and 26% in preparation of assignments and clinical cases. Lack of awareness (52%) and cost of undertaking MEDLINE on CD-ROM search (46%) were identified as important factors that discouraged the use of MEDLINE on CD-ROM. Though the above factors were recognized as important, it was concluded that the reasons for the poor use of MEDLINE on CD-ROM are multifactorial. Poor use of MEDLINE on CD-ROM could be attributed to

White mica K-Ar geochronology of HP-UHP units in the Lago di Cignana area, western Alps, Italy: Tectonic implications for exhumation

NASA Astrophysics Data System (ADS)

Gouzu, Chitaro; Yagi, Koshi; Thanh, Ngo Xuan; Itaya, Tetsumaru; Compagnoni, Roberto

2016-04-01

High-pressure and ultra-high pressure (HP-UHP) blueschist- and eclogite-facies metabasaltic and metasedimentary rocks occur in four different tectonic units near Lago di Cignana, western Alps. We have determined K-Ar ages for white micas (matrix phengite and paragonite) from the Lago di Cignana UHP unit (LCU; 39-41 Ma); the lower and upper units of the Zermatt-Saas meta-ophiolite (LU and UU; 37-38 Ma and 38-41 Ma respectively), and the Combin unit (CU; 36-40 Ma). These K-Ar ages overlap with single-grain Ar-Ar plateau ages (36-42 Ma) previously determined for phengites from LCU metasediments. Matrix white micas have been severely deformed during exhumation, and their chemistries differ from those of micas included in garnet. Although individual mica grains in the matrix could have experienced different degrees of deformation which have reset their K-Ar systems, "bulk" white mica separates provide the average age of all the individual grains in the separate. The similarity of ages determined for white micas from the LCU, LU, UU and CU units, regardless of rock type and mineral species, suggests that these four units were metamorphosed together as part of a single metamorphic sequence in the Piemonte-Liguria paleosubduction zone and were subsequently exhumed together. However, present-day structural relationship among those units and the limited occurrence of UHP minerals in LCU suggests that the exhumation of LCU was more rapid than that for LU, UU and CU. The age gaps between the youngest value of white mica K-Ar ages in each unit and the inferred timing of the metamorphic peak (U-Pb age: 44 Ma) is 5, 7, 6 and 8 Myr for LCU, LU, UU and CU, respectively. These intervals are considerably shorter than that determined for the Sanbagawa HP metamorphic belt of Southwest Japan (> 31 Myr). The short interval observed for the Lago di Cignana units that we have studied is consistent with the model of rapid exhumation of the UHP-bearing metamorphic domain, suggesting the

Determinants of Quality of Family Planning Counseling among Private Health Facilities in Lagos.

PubMed

Johnson, Doug; Ugaz, Jorge

2016-09-01

We use a unique dataset that includes an objective measure of the quality of family planning counseling from 927 private health facilities in Lagos State, Nigeria, to determine which variables at the facility and provider levels are most closely correlated with the quality of family planning counseling. Our data on quality come from mystery client surveys in which the clients posed as women seeking family planning counseling. We find that quality is strongly associated with the cadre of provider, with doctors delivering substantially higher-quality counselling than nurses. Doctors not only outperform nurses overall, but also perform better on each category of quality and spend nearly three minutes longer on average counseling the mystery client. Location, fees charged for the service, and facility type are also strongly correlated with quality. The degree to which a facility specializes in family planning and facility size are only weakly predictive of quality. © 2016 The Population Council, Inc.

Fertility and female employment in Lagos, Nigeria.

PubMed

Feyisetan, B J

1985-01-01

This paper investigates the relationship between fertility and female employment in a Nigerian urban center, Lagos. The study is built upon the data derived from the Survey of Household Structure, Family Employment, and the Small Family Ideal carried out in 1974. The study centered around currently married women aged 15-49, living in 2 residential areas chosen to include wage-earning and non wage-earning workers. It is principally a test of the maternal role incompatibility hypothesis, whose major tenet is that the maternal role and function of worker are incompatible with each other. On the basis of the assumption, the fertility and female employment equations are estimated by the 2 stage least squares procedure and estimated results compared to those derived from the ordinary least squares procedure. The results demonstrate that mothering and working tend to conflict only if employment is undertaken in the formal sector of the labor market; a positive association is discernable between the proclivity to engage in non-domestic but irregular activities of the informal sector and the bearing and rearing of children. While the conflict between fertility and female employment in the formal sector suggests possible trade-offs between the number of children and employment, the positive association between fertility and female employment in the informal sector suggests the compatibility of the roles of a mother and of a worker in that sector. The results further demonstrate the inadequacy of using a mere rural-urban dichotomy in the examination of the maternal role incompatibility hypothesis as done in some earlier works. The urban labor market, especially in a less developed country like Nigeria, needs formal disaggregation into formal and informal sectors on the basis of the activities being undertaken.

Female reproductive tract infections: understandings and care seeking behaviour among women of reproductive age in Lagos, Nigeria

PubMed Central

2010-01-01

Background Reproductive tract infections (RTI's) are endemic in developing countries and entail a heavy toll on women. If untreated, RTI's can lead to adverse health outcomes such as infertility, ectopic pregnancy and increased vulnerability to transmission of the human immunodeficiency virus. It is also associated with adverse pregnancy outcomes. While RTI's and its sequelae abound in Nigeria, there is paucity of publications on the subject in the country. This study assessed the understandings and care seeking behavior with regards to RTI's among women of reproductive age in Lagos, Nigeria with the aim of improving awareness on the subject. Methods A descriptive cross sectional survey of women attending the gynaecological outpatient and family planning clinics of the Lagos State University Teaching Hospital was carried out between 1st June 2008 and 31st August 2008 using a pre-tested questionnaire. Data was analysed using the Epi-Info 3.5 statistical software of the Centre for Disease Control and Prevention, Atlanta U.S.A. Results Most of the respondents (77.2%) had heard of RTI's. Toilet was the most perceived mode of contracting RTI's (44.6%), followed by sexual intercourse and poor hygiene. Vaginal discharge was the commonest symptom of RTI's named while inability to get pregnant was the commonest named complication. Majority of the respondent's demonstrated poor overall knowledge of symptoms and complications of RTI"s. 37.4% of the respondents had experienced symptoms of RTI's in the preceding six months. Vaginal discharge was the commonest symptom reported (21.8%) and the majority of those who reported symptoms sought medical treatment. Government health centres were the most visited health facilities for treatment. Conclusion Even though most of the respondents have heard of RTI's and sought treatment when symptomatic, they demonstrated poor overall understanding of the subject. There is need to educate women on preventive strategies, as RTI's are often

Prevalence of Malaria in Pregnant Women in Lagos, South-West Nigeria

PubMed Central

Agomo, Chimere O.; Anorlu, Rose I.; Agomo, Philip U.

2009-01-01

Prevalence rates reported for malaria in pregnancy in Nigeria vary considerably. The accuracy of results of malaria diagnosis is dependent on training, experience, and motivation of the microscopist as well as the laboratory facility available. Results of training programmes on malaria microscopy have shown low levels of sensitivity and specificity of those involved in malaria diagnosis routinely and for research. This study was done to ascertain the true prevalence of malaria in pregnancy in Lagos, South-West Nigeria. A total of 1,084 pregnant women were recruited into this study. Blood smears stained with Giemsa were used for malaria diagnosis by light microscopy. Malaria infection during pregnancy presents mostly as asymptomatic infection. The prevalence of malaria in this population was 7.7% (95% confidence interval; 6.2-9.4%). Factors identified to increase the risk of malaria infection include young maternal age (< 20 years), and gravidity (primigravida). In conclusion, this study exposes the over-diagnosis of malaria in pregnancy and the need for training and retraining of laboratory staffs as well as establishing the malaria diagnosis quality assurance programme to ensure the accuracy of malaria microscopy results at all levels. PMID:19488427

Vegetation history and palaeoclimate of the last glacial period at Lago Grande di Monticchio, Southern Italy

NASA Astrophysics Data System (ADS)

Watts, W. A.; Allen, J. R. M.; Huntley, B.

A high-resolution palynological study of a 51 m core from Lago Grande di Monticchio, southern Italy, has provided a palaeonvironmental record for the last glacill. A annual lamination based chronology, supported by radiometric and tephrochronological dates, provides an absolute timescale for this record that spans 76,300 years. Correlations are established between the pollen stratigraphy, the GRIP ice core δ18O record and foraminiferal assemblages from Atlantic core V23-81. Both Dansgaard-Oeschger and Heinrich events are reflected by changes in the pollen stratigraphy. Revised dates are estimated for Heinrich events H1-H6. A quantitative palaeoclimate reconstruction based upon the pollen data provides evidence of the climate changes in southern Italy associated with these and other fluctuations during the last glacial.

Characteristics and risk factors of preterm births in a tertiary center in Lagos, Nigeria.

PubMed

Butali, Azeez; Ezeaka, Chinyere; Ekhaguere, Osayame; Weathers, Nancy; Ladd, Jenna; Fajolu, Iretiola; Esezobor, Christopher; Makwe, Christian; Odusanya, Bukola; Anorlu, Rose; Adeyemo, Wasiu; Iroha, Edna; Egri-Okwaji, Mathias; Adejumo, Prisca; Oyeneyin, Lawal; Abiodun, Moses; Badejoko, Bolaji; Ryckman, Kelli

2016-01-01

Preterm birth is a dire complication of pregnancy that poses huge long-term medical and financial burdens for affected children, their families, and the health care system. The aim of the present study was to identify characteristics associated with preterm births at the Lagos University Teaching Hospital (LUTH), Lagos, Nigeria from 2011 to 2013. We obtained Information from 5,561 maternal, fetal/neonatal and obstetric records from the labor ward. We excluded delivery at less than 22 weeks (0.25%), post-term birth at ≥42 weeks gestation (1.3%), and unknown gestation (1.4%). Additionally, we excluded records of multiple births (5.4%) and stillbirths (8.3%) leaving 4,691 records of singleton live-births for analysis. Logistic regression analysis was performed comparing preterm birth (22-36 weeks gestation) to term birth (37-41 weeks gestation). Multiple variable models adjusting for maternal age, parity, fetal position, delivery method and booking status were also evaluated. Multinomial regression was used to identify characteristics associated with preterm birth (PTB) defined as early PTB (22-31 weeks gestation), moderate PTB (32-34 weeks gestation), late PTB (35-36 weeks gestation), compared to term birth (37-41 completed weeks gestation). From our data, 16.8% of the singleton live-birth deliveries were preterm (<37 weeks gestation). Of these, 4.7% were early (22-31 weeks), 4.5% were moderate (32-34 weeks) and 7.7% were late (35-36) PTBs. Older maternal age (≥35 years) [odds ratio (OR) = 1.41], hypertension (OR = 3.44) and rupture of membranes (OR = 4.03) were significantly associated with increased odds of PTB. Women being treated for the prevention of mother-to-child transmission of HIV were at a significantly decreased risk for PTB (OR = 0.70). Sixteen percent of women in this cohort were not registered for antenatal care in LUTH. These non-registered subjects had significantly greater odds of all categories of PTB, including early (odds ratio (OR) = 20

Complementary Feeding Knowledge, Practices, and Dietary Diversity among Mothers of Under-Five Children in an Urban Community in Lagos State, Nigeria

PubMed Central

Olatona, Foluke Adenike; Adenihun, Jesupelumi Oreoluwa; Aderibigbe, Sunday Adedeji; Adeniyi, Oluwafunmilayo Funke

2017-01-01

Background and Objectives: Inappropriate complementary feeding is a major cause of child malnutrition and death. This study determined the complementary feeding knowledge, practices, minimum dietary diversity, and acceptable diet among mothers of under-five children in an urban Local Government Area of Lagos State, Southwest Nigeria. Methods: This descriptive cross-sectional study was conducted in Eti-Osa area of Lagos State, Nigeria. Multi-stage sampling technique was employed to select 355 mothers and infants. Data was collected using a pre-tested interviewer administered questionnaire and 24-hour diet recall was used to assess dietary diversity. Data was analyzed using Epi-Info. Results: Knowledge of complementary feeding was low (14.9%) and was associated with older mothers’ age, being married, and higher level of education. The prevalence of timely initiation of complementary feeding (47.9%), dietary diversity (16.0%) and minimum acceptable diet for children between 6 and 9 months (16%) were low. Overall, appropriate complementary feeding practice was low (47.0%) and associated with higher level of mothers’ education and occupation. Conclusions and Global Health Implications: Complementary feeding knowledge and practices were poor among mothers of under-5 especially the non-literate. Reduction of child malnutrition through appropriate complementary feeding remains an important global health goal. Complementary feeding education targeting behavioral change especially among young, single and uneducated mothers in developing countries is important to reduce child morbidity and mortality. PMID:28798893

Climatic and anthropogenic forcing of prehistorical vegetation succession and fire dynamics in the Lago di Como area (N-Italy, Insubria)

NASA Astrophysics Data System (ADS)

Martinelli, Elisa; Michetti, Alessandro Maria; Colombaroli, Daniele; Mazzola, Eleonora; Motella De Carlo, Sila; Livio, Franz; Gilli, Adrian; Ferrario, Maria Francesca; Höbig, Nicole; Brunamonte, Fabio; Castelletti, Lanfredo; Tinner, Willy

2017-04-01

Combined pollen, charcoal and modeling evidence from the Insubria Region suggests that fire was a major driver of late Holocene vegetation change. However, the extent and timing of fire response dynamics are not clear yet. We use lacustrine sediments from Lago di Como (N-Italy, S-Alps) to assess if the reconstructed vegetation and fire dynamics were relevant at large scales and if they coincided in time with those observed at smaller sites. The lake, due to its size (142 km2) and economic potential, was very attractive for early land use and human presence in this area is well documented since ca. 10,000 yrs ago (Mesolithic). We used pollen, plant macrofossils and charcoal to reconstruct the vegetation composition and fire activity. During the Younger Dryas and the Early Holocene until ca. 8000 cal BP natural dynamics prevailed. Subsequently, land use and slash-and-burn activities increased at the Mesolithic-Neolithic transition and became widespread around ca. 6500 cal BP. Microscopic charcoal and numerical analyses demonstrate that anthropogenic fires had a determinant influence on long-term vegetation dynamics at regional scales in Insubria. Microscopic charcoal and pollen and spores indicative of land use show that human pressure intensified after ca. 5300 cal yr BP and even more since ca. 4300 cal yr BP. Our results suggest that important species which disappeared or were strongly reduced by land use and fire (e.g. Abies alba, Tilia, Ulmus) will potentially reestablish in the Lago di Como area and elsewhere in Insubria, if land abandonment initiated in the 1950s will continue.

Change in fish fauna as indication of aquatic ecosystem condition in Rio Grande de Morelia-Lago de Cuitzeo Basin, Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soto-Galera, E.; Paulo-Maya, J.; Lopez-Lopez, E.

1999-07-01

The Rio Grande de Morelia-Lago de Cuitzeo basin in west central Mexico has experienced major increases in water pollution from a rapidly growing human population. The authors examined changes in the long-term distribution of fishes in relation to water quality and quantity in order to assess the condition and health of aquatic ecosystems in the basin. Sampling between 1985 and 1993 revealed that five (26%) of the 19 native fish species known from the basin had been extirpated. Two of these were endemics, Chirostoma charari and C. compressum, and they are presumed extinct. Twelve (63%) of the remaining species hadmore » declines in distribution. Sixteen (80%) of the 20 localities sampled had lost species. The greatest declines occurred in Lago de Cuitzeo proper and in the lower portion of the Rio Grande de Morelia watershed. Species losses from the lake were attributable to drying and hypereutrophication of the lake because of substantial reductions in the amount and quality of tributary inputs, whereas losses from the Rio Grande de Morelia watershed were the result of pollution from agricultural, municipal, and industrial sources, especially in the region around the city of Morelia. Three localities in the upper portion of the Rio Grande de Morelia watershed--Cointzio reservoir, La Mintzita spring, and Insurgente Morelos stream--contained most of the remaining fish species diversity in the basin and deserve additional protection. Fish faunal changes indicated major declines in the health of aquatic ecosystems in the Morelia-Cuitzeo basin.« less

U-Pb zircon geochronologycal investigation on the Morro dos Seis Lagos Carbonatite Complex and associated Nb deposit (Amazonas, Brazil)

NASA Astrophysics Data System (ADS)

Rossoni, Marco B.; Bastos Neto, Artur C.; Souza, Valmir S.; Marques, Juliana C.; Dantas, Elton; Botelho, Nilson F.; Giovannini, Arthur L.; Pereira, Vitor P.

2017-12-01

We present results of U-Pb dating (by MC-ICP-MS) of zircons from samples that cover all of the known lithotypes in the Seis Lagos Carbonatite Complex and associated lateritic mineralization (the Morro dos Seis Lagos Nb deposit). The host rock (gneiss) yielded an age of 1828 ± 09 Ma interpreted as the crystallization time of this unit. The altered feldspar vein in the same gneiss yielded an age of 1839 ± 29 Ma. Carbonatite samples provided 3 groups of ages. The first group comprises inherited zircons with ages compatible with the gneissic host rock: 1819 ± 10 Ma (superior intercept), 1826 ± 5 Ma (concordant age), and 1812 ± 27 Ma (superior intercept), all from the Orosirian. The second and the third group of ages are from the same carbonatite sample: the superior intercept age of 1525 ± 21 Ma (MSWD = 0.77) and the superior intercept age of 1328 ± 58 Ma (MSWD = 1.4). The mineralogical study indicates that the ∼1.3 Ga zircons have affinity with carbonatite. It is, however, a tendence rather than a well-defined result. The data allow state that the age of 1328 ± 58 Ma represents the maximum age of the carbonatite. Without the same certainty, we consider that the data suggest that this age may be the carbonatite age, whose emplacement would have been related to the evolution of the K'Mudku belt. The best age obtained in laterite samples (a superior intercept age of 1828 ± 12 Ma) is considered the age of the main source for the inherited zircons related to the gneissic host rock.

High-risk of obstructive sleep apnea and excessive daytime sleepiness among commercial intra-city drivers in Lagos metropolis

PubMed Central

Ozoh, Obianuju B.; Okubadejo, Njideka U.; Akanbi, Maxwell O.; Dania, Michelle G.

2013-01-01

Background: The burden of obstructive sleep apnea among commercial drivers in Nigeria is not known. Aim: To assess the prevalence of high risk of obstructive sleep apnea (OSA) and excessive daytime sleepiness (EDS) among intra-city commercial drivers. Setting and Design: A descriptive cross-sectional study in three major motor parks in Lagos metropolis. Materials and Methods: Demographic, anthropometric and historical data was obtained. The risk of OSA and EDS was assessed using the STOP BANG questionnaire and the Epworth Sleepiness Scale, respectively. Statistical Analysis: The relationship between the OSA risk, EDS risk and past road traffic accident (RTA) was explored using the Pearson's chi square. Independent determinants of OSA risk, EDS risk and past RTA, respectively, were assessed by multiple logistic regression models. Result: Five hundred male commercial drivers (mean age (years) ±SD = 42.36 ± 11.17 and mean BMI (kg/m2) ±SD = 25.68 ± 3.79) were recruited. OSA risk was high in 244 (48.8%) drivers and 72 (14.4%) had EDS. There was a positive relationship between OSA risk and the risk of EDS (Pearson's X2 = 28.2, P < 0.001). Sixty-one (12.2%) drivers had a past history of RTA but there was no significant relationship between a past RTA and either OSA risk (X2 = 2.05, P = 0.15) or EDS risk (X2 = 2.7, P = 0.1), respectively. Abdominal adiposity, regular alcohol use and EDS were independent determinants of OSA risk while the use of cannabis and OSA risk were independent determinants of EDS. No independent risk factor for past RTA was identified. Conclusion: A significant proportion of commercial drivers in Lagos metropolis are at high risk of OSA and EDS. PMID:24249946

The growth history of the Lago Della Vacca (Southern Adamello Massive, Italy) intrusion from field observations, thermal and rheological modelling

NASA Astrophysics Data System (ADS)

Rust, A.; Annen, C.; Blundy, J. D.; Caricchi, L.

2010-12-01

The Lago Della Vacca granitoid is an intrusive body emplaced at about 4-6 km in up to 1 My. The core of the body is characterised by the presence of dyke-like structures, enclave-swarms and randomly distributed enclaves, which appear undeformed. Enclaves become oblate with the short axis perpendicular to the foliation, which, in turn follows the margin of the plutonic body (John and Blundy, 1993). Geothermometry and experimental data have been used to constrain the temperature of injection of the mafic component (1273-1323 K), the temperature of the host granitic magma (1173-1223), and to characterise the evolution of crystallinity with temperature for both magmas (Blundy and Sparks, 1992). Based on these data thermal and rheological modelling have been combined to interpret the growth and deformation history of the Lago della Vacca intrusive body. The pluton was modeled as a series of incrementally emplaced nested cylinders with 1D-cylindrical conductive heat transfer. The evolution of temperature and melt fraction distribution in the pluton and country rock were determined and used as input parameters for the rheological modelling. The rheology of each magma depends on the viscosity of the melt and, more importantly, on crystallinity. Field observations suggest that the mafic magma was injected as dykes. Their partial or total disaggregation produced mafic enclaves. The presence of randomly distributed enclaves in the core of Lago Della Vacca body indicates that convection was active in this portion of the intrusion. The undeformed nature of the enclaves in this region also implies that the contrast in temperature between host magma and mafic material produced a sudden (hours) rheological inversion with the mafic magma becoming more viscous than the felsic end-member. In these conditions, the enclaves would be transported passively by the felsic-host without suffering any substantial deformation. Thermal modelling indicates that to maintain the core of the pluton

Epidemiology of psychoactive drug use amongst adolescents in metropolitan Lagos, Nigeria.

PubMed

Famuyiwa, Oluwole; Aina, Olatunji F; Bankole-Oki, Olufunlayo M

2011-07-01

The study was conducted in response to the lack of epidemiological data in recent time on the use of psychoactive substances by adolescents in metropolitan Lagos-a city unique for its socio-economic profile. We considered some methodological issues omitted in several previous studies. A total of 4,286 school pupils (mean age 15.2) were anonymously administered a Self-Report Questionnaire to ascertain a range of key drug use factors in lifetime and 1-year periods. The rate of use of most of the 14 substances investigated was much higher than reported in any other study on comparable population sample. We found that 61.8 and 32.1% of respondents have used one or more substances in their lifetime and in the past 1 year, respectively. High lifetime rates of use were found for common stimulants: coffee, kolanut, and prescription drugs (barbiturates and minor tranquilisers). The rate of use of proscribed addictive substances, cannabis, heroin, and cocaine, ranged between 4.0 and 4.8%. Missing data and non-response rates were few; however, social acquiescence, under and over reporting, could be mitigant to estimation of rates and patterns of use. We advocate properly articulated school-based educative programmes that can facilitate drug demand reduction.

HOLOCENE MASS-WASTING EVENTS IN LAGO FAGNANO, TIERRA DEL FUEGO (54°S): IMPLICATIONS FOR PALEOSEISMICITY OF THE MAGALLANES-FAGNANO TRANSFORM FAULT

NASA Astrophysics Data System (ADS)

Ariztegui, D.; Waldmann, N.; Austin, J. A.; Anselmetti, F.; Moy, C.; Dunbar, R. B.

2009-12-01

High-resolution seismic imaging and sediment coring in Lago Fagnano, located along the Magallanes-Fagnano plate boundary in Tierra del Fuego, have revealed a chronologic catalog of Holocene mass-wasting events. These event layers are interpreted as resulting from slope instabilities that load the slope-adjacent lake floor during mass flow deposition thus mobilizing basin floor sediments through gravity spreading. A total of 22 mass flow deposits have been identified combining results from an 800 km-long dense grid of seismic profiles with a series of sediment cores. Successions of up to 6 m-thick mass-flow deposits pond the basin floor spreading eastward and westward following the main axis of the eastern sub-basin of Lago Fagnano. An age model on the basis of information from previous studies and from new radiocarbon dating allowed establishing a well-constrained chronologic mass-wasting event catalogue covering the last ~15000 years. Simultaneously-triggered basin-wide lateral slope failure and the formation of multiple debris flow and megaturbidite deposits are interpreted as the fingerprint of paleo-seismic activity along the Magallanes-Fagnano transform fault that runs along the entire lake basin. The slope failures and megaturbidites are interpreted as recording large earthquakes occurring along the transform fault since the early Holocene. The results from this study provide new data about the frequency and possible magnitude of Holocene earthquakes in Tierra del Fuego, which can be applied in the context of seismic hazard assessment in southernmost Patagonia.

Once daily maraviroc 300 mg or 150 mg in combination with ritonavir-boosted darunavir 800/100 mg.

PubMed

Okoli, Chinyere; Siccardi, Marco; Thomas-William, Sathish; Dufty, Ngozi; Khonyongwa, Kirstin; Ainsworth, Jonathan; Watson, John; Cook, Roseanne; Gandhi, Kate; Hickinbottom, Geraldine; Owen, Andrew; Taylor, Stephen

2012-03-01

To describe the pharmacokinetics of maraviroc when dosed at 150 or 300 mg once daily with 800/100 mg of darunavir/ritonavir. A retrospective case-note review of HIV-infected adults taking maraviroc was conducted. Patients on a maraviroc-based regimen for a minimum of 5 weeks were grouped as receiving: (i) 300 mg of maraviroc twice daily with 245 mg of tenofovir/200 mg of emtricitabine; (ii) 300 mg of maraviroc once daily with 800/100 mg of darunavir/ritonavir once daily; and (iii) 150 mg of maraviroc once daily with 800/100 mg of darunavir/ritonavir once daily. C(trough) and C(peak) data were collected at 2, 12 or 24 h post-dose. Sixty-six patients were included, providing 115 samples. The median (IQR) C(peak) was 378 (350-640) ng/mL for 300 mg of maraviroc twice daily with 245 mg of tenofovir/200 mg of emtricitabine (n=9), 728 (378-935) ng/mL for 300 mg of maraviroc once daily with darunavir/ritonavir (n=29) and 364 (104-624) ng/mL for 150 mg of maraviroc once daily with darunavir/ritonavir (n=2; P=0.24). The median (IQR) C(trough) was 46 (33-61) ng/mL for 300 mg of maraviroc twice daily with 245 mg of tenofovir/200 mg of emtricitabine (n=12), 70 (49-97) ng/mL for 300 mg of maraviroc once daily with darunavir/ritonavir (n=34) and 43 (35-55) ng/mL for 150 mg of maraviroc once daily with darunavir/ritonavir (n=17; P=0.001). The maraviroc C(trough) in black patients (n=34) was 61 (45-110) ng/mL and in white patients (n=29) it was 49 (42-70) ng/mL (P=0.04). The C(peak) in black patients (n=20) was 800 (397-1060) ng/mL versus 387 (336-723) ng/mL in white patients (n=20; P=0.02). Once daily coadministration of 300 mg of maraviroc with 800/100 mg of darunavir/ritonavir was well tolerated and had favourable pharmacokinetics when compared with 300 mg of maraviroc twice daily with 245 mg of tenofovir/200 mg of emtricitabine. A 24% higher C(trough) and 107% higher C(peak) was seen in black patients compared with white patients.

Review article: A review and critical analysis of the efforts towards urban flood risk management in the Lagos region of Nigeria

NASA Astrophysics Data System (ADS)

Nkwunonwo, U. C.; Whitworth, M.; Baily, B.

2016-02-01

Urban flooding has been and will continue to be a significant problem for many cities across the developed and developing world. Crucial to the amelioration of the effects of these floods is the need to formulate a sound flood management policy, which is driven by knowledge of the frequency and magnitude of impacts of these floods. Within the area of flood research, attempts are being made to gain a better understanding of the causes, impacts, and pattern of urban flooding. According to the United Nations office for disaster reduction (UNISDR), flood risk is conceptualized on the basis of three integral components which are frequently adopted during flood damage estimation. These components are: probability of flood hazard, the level of exposure, and vulnerabilities of elements at risk. Reducing the severity of each of these components is the objective of flood risk management under the UNISDR guideline and idea of "living with floods". On the basis of this framework, the present research reviews flood risk within the Lagos area of Nigeria over the period 1968-2012. During this period, floods have caused harm to millions of people physically, emotionally, and economically. Arguably over this period the efforts of stakeholders to address the challenges appear to have been limited by, amongst other things, a lack of reliable data, a lack of awareness amongst the population affected, and a lack of knowledge of flood risk mitigation. It is the aim of this research to assess the current understanding of flood risk and management in Lagos and to offer recommendations towards future guidance.

Characteristics and risk factors of preterm births in a tertiary center in Lagos, Nigeria

PubMed Central

Butali, Azeez; Ezeaka, Chinyere; Ekhaguere, Osayame; Weathers, Nancy; Ladd, Jenna; Fajolu, Iretiola; Esezobor, Christopher; Makwe, Christian; Odusanya, Bukola; Anorlu, Rose; Adeyemo, Wasiu; Iroha, Edna; Egri-Okwaji, Mathias; Adejumo, Prisca; Oyeneyin, Lawal; Abiodun, Moses; Badejoko, Bolaji; Ryckman, Kelli

2016-01-01

Introduction Preterm birth is a dire complication of pregnancy that poses huge long-term medical and financial burdens for affected children, their families, and the health care system. The aim of the present study was to identify characteristics associated with preterm births at the Lagos University Teaching Hospital (LUTH), Lagos, Nigeria from 2011 to 2013. Methods We obtained Information from 5,561 maternal, fetal/neonatal and obstetric records from the labor ward. We excluded delivery at less than 22 weeks (0.25%), post-term birth at ≥42 weeks gestation (1.3%), and unknown gestation (1.4%). Additionally, we excluded records of multiple births (5.4%) and stillbirths (8.3%) leaving 4,691 records of singleton live-births for analysis. Logistic regression analysis was performed comparing preterm birth (22-36 weeks gestation) to term birth (37-41 weeks gestation). Multiple variable models adjusting for maternal age, parity, fetal position, delivery method and booking status were also evaluated. Multinomial regression was used to identify characteristics associated with preterm birth (PTB) defined as early PTB (22-31 weeks gestation), moderate PTB (32-34 weeks gestation), late PTB (35-36 weeks gestation), compared to term birth (37-41 completed weeks gestation). Results From our data, 16.8% of the singleton live-birth deliveries were preterm (<37 weeks gestation). Of these, 4.7% were early (22-31 weeks), 4.5% were moderate (32-34 weeks) and 7.7% were late (35-36) PTBs. Older maternal age (≥35 years) [odds ratio (OR) = 1.41], hypertension (OR = 3.44) and rupture of membranes (OR = 4.03) were significantly associated with increased odds of PTB. Women being treated for the prevention of mother-to-child transmission of HIV were at a significantly decreased risk for PTB (OR = 0.70). Sixteen percent of women in this cohort were not registered for antenatal care in LUTH. These non-registered subjects had significantly greater odds of all categories of PTB, including

Esomeprazole 40 mg provides more effective intragastric acid control than lansoprazole 30 mg, omeprazole 20 mg, pantoprazole 40 mg and rabeprazole 20 mg in patients with gastro-oesophageal reflux symptoms.

PubMed

Röhss, Kerstin; Lind, Tore; Wilder-Smith, Clive

2004-10-01

To compare the effect of esomeprazole 40 mg with lansoprazole 30 mg, omeprazole 20 mg, pantoprazole 40 mg and rabeprazole 20 mg on intragastric pH during single and repeated dosing in four separate studies in patients with symptoms of gastro-oesophageal reflux disorder (GERD). In four randomised crossover studies, patients with symptoms of GERD received once-daily treatment with esomeprazole 40 mg or lansoprazole 30 mg (study A), omeprazole 20 mg (study B), pantoprazole 40 mg (study C) and rabeprazole 20 mg (study D) for 5 days. Continuous 24-h intragastric pH recording was performed on days 1 (except study B) and 5. Percentage of time over 24 h with intragastric pH greater than 4, 24-h median pH and the proportion of patients with pH greater than 4 for greater than or equal to 12 h and 16 h during the 24-h recording periods were investigated. In all four studies, esomeprazole 40 mg OD maintained intragastric pH greater than 4 for a significantly higher mean percentage of the 24-h period compared with all other proton pump inhibitors (PPIs) on days 1 (esomeprazole 40.6% versus lansoprazole 33.4%, P=0.0182; esomeprazole 50.3% versus pantoprazole 29.1%, P<0.001; esomeprazole 41.0% versus rabeprazole 29.4%, P=0.002) and 5 (esomeprazole 57.7% versus lansoprazole 44.5%, P<0.0001; esomeprazole 69.8% versus omeprazole 43.7%, P<0.0001; esomeprazole 67.0% versus pantoprazole 44.8%, P<0.001; esomeprazole 59.4% versus rabeprazole 44.5%, P<0.0001). Higher 24-h median pH and a higher proportion of patients with intragastric pH greater than 4 for greater than or equal to 12 h and 16 h were reported with esomeprazole 40 mg OD than with all the other PPIs in each study. Esomeprazole 40 mg provides greater acid control in more patients and maintains intragastric pH greater than 4 for a longer period than lansoprazole 30 mg, omeprazole 20 mg, pantoprazole 40 mg and rabeprazole 20 mg in patients with symptoms of GERD.

Knowledge, perceptions and practice of cervical cancer prevention among female public secondary school teachers in Mushin local government area of Lagos State, Nigeria

PubMed Central

Toye, Mariam Adeola; Okunade, Kehinde Sharafadeen; Roberts, Alero Ann; Salako, Omolola; Oridota, Ezekiel Sofela; Onajole, Adebayo Temitayo

2017-01-01

Introduction Cervical cancer is the most common gynecological cancer and a leading cause of cancer death in women in Nigeria. This study was aimed to assess the knowledge, perception, and practice of cervical cancer prevention among female public secondary school teachers in Mushin, Lagos. Methods This was a cross-sectional study carried out among female secondary school teachers in Mushin, Lagos. The participants were selected by a two-stage random sampling method and relevant data were collected with the use a self-administered questionnaire. Data entry and analysis were done using Epi-info version 7.2 statistical software and descriptive statistics were computed for all data. Results The knowledge of cervical cancer and its prevention was 100.0% among the respondents. The most commonly known method of cervical cancer screening identified by the respondents was Papanicolaou smear (91.4%). More than half of the women (67.0%) have had at least one cervical cancer screening done previously. Only 2.2% of the respondents have had HPV vaccine given to their female teenage children in the past despite the acceptance rate for HPV vaccination being 76.2%. Conclusion This study, unlike most previous studies in other regions of Nigeria and most part of sub-Saharan Africa, has demonstrated a relatively high level of awareness about cervical cancer, its cause, risk factors and prevention. However, conversely, the absence of a national health programme means that screening and vaccination centers are not available, accessible or affordable. PMID:29629007

Cathodic Deposition of Mg(OH)2 Coatings on Pure mg in Three mg Salts Aqueous Solutions

NASA Astrophysics Data System (ADS)

Yongjun, Zhang; Xiaomeng, Pei; Shugong, Jia

Film-forming effects of cathodic deposition on pure Mg substrate at constant DC in aqueous solutions of magnesium nitrate (Mg(NO3)2ṡ6H2O), magnesium chloride (MgCl2ṡ6H2O) and magnesium sulfate (MgSO4ṡ7H2O) respectively were investigated systematically. Typical processes were studied by potentiodynamic cathodic polarization and galvanostatic polarization and typical samples were analyzed by SEM and XRD. The results indicate that the depositing efficiency is not only the highest but stablest, and deposited coatings show the best uniformity with Mg(NO3)2ṡ6H2O solution employed as depositing medium and applied current density ≥1.0mA cm-2. Cathodic deposition leads to regular mass loss of Mg substrate. The cathodic polarization curve of pure Mg in magnesium nitrate solution shows more obvious pseudo-passivation, several Tafel regions with different slopes appearing before diffusion-limited current density region, and oxygen consumption is the major cathodic reduction reaction under specified current density. However, hydrogen evolution reaction is dominant in both Mg chloride and Mg sulfate solutions. The deposition coatings are all composed of continuous and uniform mesh-like “basic layer” adjacent to substrate and discrete distributed snowball-like particles on the microscopic scale. The phase compositions are all crystal Mg(OH)2, and the coatings deposited in Mg chloride solution have (011) preferred orientation.

Efficacy and Safety of Doxepin 1 mg, 3 mg, and 6 mg in Adults with Primary Insomnia

PubMed Central

Roth, Thomas; Rogowski, Roberta; Hull, Steven; Schwartz, Howard; Koshorek, Gail; Corser, Bruce; Seiden, David; Lankford, Alan

2007-01-01

Study Objectives: To evaluate the efficacy and safety of doxepin 1, 3, and 6 mg in insomnia patients. Design: Adults (18-64 y) with chronic primary insomnia (DSM-IV) were randomly assigned to one of four sequences of 1 mg, 3 mg, and 6 mg of doxepin, and placebo in a crossover study. Treatment periods consisted of 2 polysomnographic assessment nights with a 5-day or 12-day drug-free interval between periods. Efficacy was assessed using polysomnography (PSG) and patient-reported measures. Safety analyses included measures of residual sedation and adverse events. Measurements and Results: Sixty-seven patients were randomized. Wake time during sleep, the a priori defined primary endpoint, was statistically significantly improved at the doxepin 3 mg and 6 mg doses versus placebo. All three doses had statistically significant improvements versus placebo for PSG-defined wake after sleep onset, total sleep time, and overall sleep efficiency (SE). SE in the final third-of-the-night also demonstrated statistically significant improvement at all doses. The doxepin 6 mg dose significantly reduced subjective latency to sleep onset. All three doxepin doses had a safety profile comparable to placebo. There were no statistically significant differences in next-day residual sedation, and sleep architecture was generally clinically preserved. Conclusions: In adults with primary insomnia, doxepin 1 mg, 3 mg, and 6 mg was well-tolerated and produced improvement in objective and subjective sleep maintenance and duration endpoints that persisted into the final hour of the night. The side-effect profile was comparable to placebo, with no reported anticholinergic effects, no memory impairment, and no significant hangover/next-day residual effects. These data demonstrate that doxepin 1 mg, 3 mg, and 6 mg is efficacious in improving the sleep of patients with chronic primary insomnia. Citation: Roth T; Rogowski R; Hull S; Schwartz H; Koshorek G; Corser B; Seiden D. Efficacy and safety of

The effect of the MgO buffer layer thickness on magnetic anisotropy in MgO/Fe/Cr/MgO buffer/MgO(001)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozioł-Rachwał, Anna, E-mail: a.koziolrachwal@aist.go.jp; AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków; Nozaki, Takayuki

2016-08-28

The relationship between the magnetic properties and MgO buffer layer thickness d was studied in epitaxial MgO/Fe(t)/Cr/MgO(d) layers grown on MgO(001) substrate in which the Fe thickness t ranged from 0.4 nm to 1.1 nm. For 0.4 nm ≤ t ≤ 0.7 nm, a non-monotonic coercivity dependence on the MgO buffer thickness was shown by perpendicular magneto-optic Kerr effect magnetometry. For thicker Fe films, an increase in the buffer layer thickness resulted in a spin reorientation transition from perpendicular to the in-plane magnetization direction. Possible origins of these unusual behaviors were discussed in terms of the suppression of carbon contamination at the Fe surface and changes inmore » the magnetoelastic anisotropy in the system. These results illustrate a method to control magnetic anisotropy in MgO/Fe/Cr/MgO(d) via an appropriate choice of MgO buffer layer thickness d.« less

Herbal medicine use among urban residents in Lagos, Nigeria

PubMed Central

2011-01-01

Background Over three-quarter of the world's population is using herbal medicines with an increasing trend globally. Herbal medicines may be beneficial but are not completely harmless. This study aimed to assess the extent of use and the general knowledge of the benefits and safety of herbal medicines among urban residents in Lagos, Nigeria. Methods The study involved 388 participants recruited by cluster and random sampling techniques. Participants were interviewed with a structured open- and close-ended questionnaire. The information obtained comprises the demography and types of herbal medicines used by the respondents; indications for their use; the sources, benefits and adverse effects of the herbal medicines they used. Results A total of 12 herbal medicines (crude or refined) were used by the respondents, either alone or in combination with other herbal medicines. Herbal medicines were reportedly used by 259 (66.8%) respondents. 'Agbo jedi-jedi' (35%) was the most frequently used herbal medicine preparation, followed by 'agbo-iba' (27.5%) and Oroki herbal mixture® (9%). Family and friends had a marked influence on 78.4% of the respondents who used herbal medicine preparations. Herbal medicines were considered safe by half of the respondents despite 20.8% of those who experienced mild to moderate adverse effects. Conclusions Herbal medicine is popular among the respondents but they appear to be ignorant of its potential toxicities. It may be necessary to evaluate the safety, efficacy and quality of herbal medicines and their products through randomised clinical trial studies. Public enlightenment programme about safe use of herbal medicines may be necessary as a means of minimizing the potential adverse effects. PMID:22117933

Physical health status of pupils in a school for the mentally disabled in Lagos.

PubMed

Ezeaka, V C; Iroha, E O

2003-12-01

The study set out to assess the health status of pupils of a school for children with mental disability. The school is Modupe Cole Memorial Child Care and Treatment Home School, Akoka, Lagos. The records of 211 pupils were reviewed and the pupils were clinically examined by the author. Seventy-four (35.1%) of the subjects had complete immunization, 48(22.7%) had incomplete immunization while 44(20.9%) received no immunization. The probable aetiology of mental disability in the subjects was due to postnatal causes (96; 45.5%), natal causes (44; 20.8%), prenatal causes (12; 5.7%) and unknown (59; 28.0%). The most abnormal findings on physical examination were in the central nervous system (199; 94.3%), the musculoskeletal system (137; 64.9%), the mouth/teeth (125; 59.2%) and the skin (98; 46.4%). These findings were worse amongst the residential students than in the non-residential students (p < 0.001). The information obtained from this study will help to serve as a reference for purposes of health planning and policy formulation for children with mental disability.

Ocular findings seen among the staff of an institution in Lagos, Nigeria.

PubMed

Ashaye, A O; Asuzu, M C

2005-01-01

The degree to which ocular morbidity affects workers productivity in the developing countries has not been studied adequately. A federal government research institute based in Lagos introduced an annual health screen for all its workers, which included eye tests. This provided an opportunity to study the pattern of ocular conditions among workers who were 30 years and above, and to determine the effect of eye diseases on the workers productivity. Detailed eye examination including refraction, was done on every respondent at the institution's clinic by an ophthalmologist. A questionnaire on ocular health status and occupational history was administered independently by an ophthalmic nurse. Sickness absenteeism, use of the clinic were obtained from clinic records, and the results were analysed. The common ocular conditions were uncorrected or poorly corrected refractive error, uncorrected or poorly corrected presbyopia and allergic. conjunctivitis. Glaucoma, maculopathy and optic atrophy were causes of severe visual impairment or blindness in 1.9 % of the subjects. Absenteeism and clinic use were more common in subjects with ocular morbidity than those with non-ocular morbidity. Subjects with ocular morbidity had more illnesses, absenteeism and used the clinic more. Ocular problems which reduce worker's productivity are prevalent among the staff of the institution studied. They are mostly unrecognised.

AB Initio Characterization of MgCCH, MgCCH(+), and MgC2, and Pathways to their Formation in the Interstellar Medium

NASA Technical Reports Server (NTRS)

Woon, David E.

1996-01-01

A study of Mg-bearing compounds has been performed in order to determine molecular properties which are critical for planning new astronomical searches and laboratory studies. The primary focus of the work is on MgCCH, MgCCH(+), and the isomers of MgC2. Only MgCCH has been identified in laboratory studies. Additional calculations have been carried out on MgH, MgNC, MgCN, and their cations in an effort to evaluate pathways to the formation of MgCCH and MgCCH(+) in the InterStellar Medium (ISM) or in circumstellar envelopes. Correlated ab initio methods and correlation-consistent basis sets have been employed. Properties including structures, rotational constants, dipole moments, and harmonic frequencies are reported. A transition state between linear MgCC and cyclic MgC2 has been characterized and was found to yield a minimal barrier (approx. 0.5 kcal/mole), indicating easy interconversion to the cyclic form. Direct reactions in the ISM between Mg or Mg(+) and HCCH are precluded by energetic considerations, but a number of ion- molecule or neutral-neutral exchange reactions between CCH and various Mg-containing species offer plausible pathways to MgCCH or MgCCH(+). Weakly bound MgH may react with CCH to form MgCCH, but MgH has not been detected. Both MgNC and MgCN have been observed, but reactions with CCH are slightly endothermic by 1-3 kcal/mole. Although MgH(+), MgNC(+), and MgCN(+) have not been detected, their reactions with CCH to form MgCCH(+) are all exothermic. With only a small barrier separating linear MgCC and cyclic MgC2, the dissociative recombination of MgCCH(+) with an electron is expected to yield cyclic MgC2, and regenerate Mg and CCH. New astronomical searches for MgCCH, MgCCH(+), cyclic MgC2, MgNC(+), and MgCN(+) will provide further insight into organo-magnesium astrochemistry.

Observations of local interstellar Mg I and Mg II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruhweiler, F.C.; Oegerle, W.; Weiler, E.

1984-11-01

Copernicus and IUE observations of 5 stars within 50 pc of the Sun were combined to study the ionization of magnesium in the Local Interstellar Medium (LISM). The high resolution Copernicus spectrometer was used to detect interstellar MG I 2852 in the spectra of alpha Gru, alpha Eri, and alpha Lyr, while placing upper limits on Mg I in the spectra of alpha CMa and alpha PsA. Observations of Mg II 2795, 2802 for these stars were also obtained with IUE and Copernicus. The column densities of Mg I and Mg II are used to place constraints on the temperaturemore » of the LISM.« less

Observations of Local Interstellar Mg I and Mg II

NASA Technical Reports Server (NTRS)

Bruhweiler, F. C.; Oegerle, W.; Weiler, E.; Stencel, R. E.; Kondo, Y.

1984-01-01

Copernicus and IUE observations of 5 stars within 50 pc of the Sun were combined to study the ionization of magnesium in the local interstellar medium (LISM). The high resolution Copernicus spectrometer was used to detect interstellar MG I 2852 in the spectra of alpha Gru, alpha Eri, and alpha Lyr, while placing upper limits on Mg I in the spectra of alpha CMa and alpha PsA. Observations of Mg II 2795, 2802 for these stars were also obtained with IUE and Copernicus. The column densities of Mg I and Mg II are used to place constraints on the temperature of the LISM.

Multichannel analysis of the surface waves of earth materials in some parts of Lagos State, Nigeria

NASA Astrophysics Data System (ADS)

Adegbola, R. B.; Oyedele, K. F.; Adeoti, L.; Adeloye, A. B.

2016-09-01

We present a method that utilizes multichannel analysis of surface waves (MASW), which was used to measure shear wave velocities, with a view to establishing the probable causes of road failure, subsidence and weakening of structures in some local government areas in Lagos, Nigeria. MASW data were acquired using a 24-channel seismograph. The acquired data were processed and transformed into a two-dimensional (2-D) structure reflective of the depth and surface wave velocity distribution within a depth of 0-15 m beneath the surface using SURFSEIS software. The shear wave velocity data were compared with other geophysical/ borehole data that were acquired along the same profile. The comparison and correlation illustrate the accuracy and consistency of MASW-derived shear wave velocity profiles. Rigidity modulus and N-value were also generated. The study showed that the low velocity/ very low velocity data are reflective of organic clay/ peat materials and thus likely responsible for the failure, subsidence and weakening of structures within the study areas.

Diverticular disease at colonoscopy in Lagos State, Nigeria.

PubMed

Oluyemi, Aderemi; Odeghe, Emuobor

2016-01-01

The upsurge in the reported cases of diverticular disease (DD) has led to a re-appraisal of the earlier held views that it was a rare entity in Nigeria. The advent of colonoscopy has contributed in no small way to this change. We sought to determine the clinical characteristics, indications for colonoscopy, and intra-procedural findings among these patients. A retrospective cross-sectional study was carried out on the colonoscopy records from four private endoscopy units based in Lagos State, Nigeria. The records were drawn from a 5-year period (August 2010 to July 2015). The endoscopy logs and reports were reviewed, and the bio data, indications, and colonoscopy findings were gleaned. A total of 265 colonoscopies were carried out in the stated period. Of these, 28 (10.6%) had DD. Of the patients with DD, 5 (17.9%) were females while 23 (82.1%) were males. Their ages ranged from 46 to 94 years (mean = 68.2 ± 11 years). Fifteen patients had been referred for the procedure on account of hematochezia alone (15 = 53.6%). Other reasons for referral included abdominal pain alone (2 = 7%), hematochezia plus abdominal pain (5 = 17.9%), and change in bowel habits (3 = 10.8%). Ten (35%) patients had pan-colonic involvement. Regional disease involved the right side alone in only one case (3.5%) while the other combinations of sites are as follows; 6 (21.4%) in the sigmoid colon alone, 2 (7%) in the descending colon alone, 5 (17.9%) in the sigmoid-descending colon, 4 (14.3%) in the sigmoid-descending-transverse colon, thus the sigmoid colon was involved in 25 (89.3%) cases. Five cases (17.9%) had endoscopic features suggestive of diverticulitis. DD should no longer be regarded as a rare problem in the Nigerian patient. The study findings support the notion of higher prevalence among the elderly, in males, and of sigmoid colon involvement.

Main reinforcement effects of precipitation phase Mg2Cu3Si, Mg2Si and MgCu2 on Mg-Cu-Si alloys by ab initio investigation

NASA Astrophysics Data System (ADS)

Shi, Xue-Feng; Wang, Hai-Chen; Tang, Ping-Ying; Tang, Bi-Yu

2017-09-01

To predict and compare the main reinforcement effects of the key precipitation phases Mg2Cu3Si, Mg2Si and MgCu2 in Mg-Cu-Si alloy, the structural, mechanical and electronic properties of these phases have been studied by ab initio calculations. The lowest formation enthalpy and cohesive energy indicate that Mg2Cu3Si has the strongest alloying ability and structural stability. The mechanical modulus indicates that Mg2Cu3Si has the strongest resistance to reversible shear/volume distortion and has maximum hardness. The characterization of brittle (ductile) behavior manifests that MgCu2 has favorable ductility. Meanwhile the evaluation of elastic anisotropy indicates that Mg2Si possesses elastic isotropy. Debye temperature prediction shows that Mg2Si and Mg2Cu3Si have better thermal stability. To achieve an unbiased interpretation on the phase stability and mechanical behavior of these precipitation phases, the density of states and differential charge densities are also analyzed. The current study deepens the comprehensive understanding of main reinforcement effects of these precipitation phases on Mg-Cu-Si alloys, and also benefits to optimize the overall performances of Mg-Cu-Si alloy from the hardness, ductility and thermal stability by controlling these second precipitation phases during the heat treatment process.

A Retrospective Study of the Health Profile of Neonates of Mothers with Anemia in Pregnancy and Pregnancy Induced Hypertension in Lagos, Nigeria.

PubMed

Sotunde, Olusola Funmilayo; Sanni, Silifat Ajoke; Onabanjo, Oluseye Olusegun; Olayiwola, Ibiyemi O; Agbonlahor, Mure

2014-06-29

Our study assessed the health profile of neonates in relation to anemia in pregnancy and pregnancy induced hypertension (PIH). This was a retrospective study where a systematic random sampling technique was used to select a total of 1046 case records of pregnant women registered for ante-natal care at Lagos Island Maternity Hospital, Lagos, Nigeria, between 2005 and 2009. Socio-demographic characteristics of the mothers, prevalence of anemia and PIH, and neonatal health profile were obtained from the case records and were analyzed using both descriptive and inferential statistics. Pearson product moment correlation was used to show the relationship (P≤0.05) between maternal complications and neonatal health profile. Majority (68.8%) of the mothers had anemia and 6.7 % had PIH. Majority (97.12%) of the neonates were live births and 2.88% of the neonates were still births, 65.4% of the women with still birth pregnancy outcome had anemia, and 34.6% had PIH. Majority (74%) of the neonates had birth weight within normal range (2.5-4.0 kg) and majority (68%) had normal Apgar score at 5 min of birth (7-10). A positive correlation existed between the packed cell volume of the mother and the birth weight of the neonates (r=0.740, P≤0.05). A negative correlation existed between the incidence of PIH and the birth weight of the neonates (r= 0.781, P≤0.05), head circumference (r=-0.491, P≤0.05) and the length of the neonates(r=-0.480, P≤0.05). We conclude that nutritional and health care intervention programmes for pregnant women should be intensified especially during ante-natal visits to hospitals.

Re-examining the 26Mg(α ,α')26Mg reaction: Probing astrophysically important states in 26Mg

NASA Astrophysics Data System (ADS)

Adsley, P.; Brümmer, J. W.; Li, K. C. W.; Marín-Lámbarri, D. J.; Kheswa, N. Y.; Donaldson, L. M.; Neveling, R.; Papka, P.; Pellegri, L.; Pesudo, V.; Pool, L. C.; Smit, F. D.; van Zyl, J. J.

2017-11-01

Background: The 22Ne(α ,n )25Mg reaction is one of the neutron sources for the s process in massive stars. The properties of levels in 26Mg above the α -particle threshold control the strengths of the 22Ne(α ,n )25Mg and 22Ne(α ,γ )26Mg reactions. The strengths of these reactions as functions of temperature are one of the major uncertainties in the s process. Purpose: Information on the existence, spin, and parity of levels in 26Mg can assist in constraining the strengths of the 22Ne(α ,γ )26Mg and 22Ne(α ,n )25Mg reactions, and therefore in constraining s -process abundances. Methods: Inelastically scattered α particles from a 26Mg target were momentum-analyzed in the K600 magnetic spectrometer at iThemba LABS, South Africa. The differential cross sections of states were deduced from the focal-plane trajectory of the scattered α particles. Based on the differential cross sections, spin and parity assignments to states are made. Results: A newly assigned 0+ state was observed in addition to a number of other states, some of which can be associated with states observed in other experiments. Some of the deduced Jπ values of the states observed in the present study show discrepancies with those assigned in a similar experiment performed at RCNP Osaka. The reassignments and additions of the various states can strongly affect the reaction rate at low temperatures. Conclusion: The number, location, and assignment of levels in 26Mg that may contribute to the 22Ne+α reactions are not clear. Future experimental investigations of 26Mg must have an extremely good energy resolution to separate the contributions from different levels. Coincidence experiments of 26Mg provide a possible route for future investigations.

Evaluation of outcomes of tuberculosis management in private for profit and private-not-for profit directly observed treatment short course facilities in Lagos State, Nigeria.

PubMed

Adejumo, Olusola Adedeji; Daniel, Olusoji James; Otesanya, Andrew Folarin; Salisu-Olatunj, Shukrat Olajumoke; Abdur-Razzaq, Husseine A

2017-01-01

The engagement of private practitioners in the public-private mix of tuberculosis (TB) management started in 2007 in Lagos State Nigeria. This study compared the treatment outcomes of patients managed at private for profit (PFP) and private not for profit (PNFP) directly observed treatment short course (DOTS) facilities. A retrospective review of treatment cards of TB patients managed between January 1, 2012, and June 30, 2012, in seven PFP and four PNFP DOTS facilities that served as treatment and microscopy center under the Lagos State TB and Leprosy Control Programme (LSTBLCP) at least 2 years before data collection was conducted. A total of 372 treatment cards of TB patients were reviewed, of which 132 (35.5%) and 240 (64.5%) were from PFP and PNFP DOTS facilities, respectively. Treatment success rate was higher among patients managed at PFP (89.4%) DOTS facilities than PNFP (81.3%) DOTS facilities ( P = 0.04). The proportion of patients lost to follow-up (12.5% vs. 8.3%), dead (3.3% vs. 1.5%) and treatment failure (2.5% vs. 0.8%) was higher among patients managed at PNFP DOTS facilities ( P > 0.05). The odds that patients treated at PFP DOTS facilities had treatment success were about four times higher than PNFP DOTS facilities when other variables have been controlled for ( P < 0.05). There is need by the LSTBLCP to engage more private practitioners to increase case detection and improve treatment outcomes of TB patients.

A multi-proxy lake core record from Lago Lungo, Rieti Basin, Lazio, Italy and its relation to human activities in the catchment during the last century

NASA Astrophysics Data System (ADS)

Noble, Paula; Tunno, Irene; Mensing, Scott; Piovesan, Gianluca

2016-04-01

The lakes of the Rieti Basin have experienced extensive human modification dating back to pre-Roman times, yet lake archives indicate that the most profound changes to the aquatic ecosystem have occurred during the last century. Analysis of the upper ˜120 cm segment of a sediment core from Lago Lungo, dating back to ˜1830 CE, show changes in water quality and hydrologic inflow largely attributed to 20th century reclamation and land use activities. Lago Lungo is a shallow, small, eutrophic, hard water lake situated in an intermontaine alluvial plain ˜90 km NE of Rome. It is one of several remnant lakes in a poorly drained wetland area fed by numerous springs. Reclamation activities over the last century have substantially altered the drainage network affecting water delivery to the lakes and their connectivity. There are 3 interesting signals in the core. First, small Stephanodiscus species, associated with hypereutrophic conditions, appear after 1950, peak ˜1990, and may be attributed to increased use of chemical fertilizers and intensification of local agriculture. Elemental proxies from scanning XRF data (abundances of Ti, Si/Ti, and Ca) are consistent with increased eutrophication starting ˜1950. A decline in Stephanodicsus after 1990 reflects some improvement to the water quality following the lake's incorporation into a nature preserve and creation of a narrow vegetation buffer. Intermittent water quality measurements from 1982 onward corroborate the changes in trophic status interpreted from the core record. Second, a large change in the core stratigraphy, elemental geochemistry, and diatom composition occurs ˜1940 and is associated with several major reclamation efforts, including the rerouting of the Santa Susanna channel, which redirected large volumes of artesian inflows away from the lakes and estuarine system. Upstream, dams on the Turano and Salto rivers were also constructed, further affecting hydrological inflows into the basin. From ˜1900

Transactional sex, condom and lubricant use among men who have sex with men in Lagos State, Nigeria.

PubMed

Ayoola, Oluyemisi O; Sekoni, Adekemi O; Odeyemi, Kofoworola A

2013-12-01

Men who have unprotected sex with men may also have unprotected sex with women and thus serve as an epidemiological bridge for HIV to the general population. This cross sectional descriptive study assessed condom and lubricant use and practice of transactional sex among men who have sex with men (MSM) in Lagos state. Simple random sampling was used to select three community centres and snowball sampling technique was used to recruit 321 respondents. Almost half (50.9%) had received payment for sex while 45.4% had paid for sex in the past. Consistent condom use was practiced by 40.5% of respondents during the last 10 sexual encounters, 85.6% used lubricants mostly with condom, products used were KY jelly, body cream, saliva and Vaseline. There is need for behavioural change to reduce risky practices which predisposes this group of MSM to HIV and sexually transmitted infections.

Educational intervention and the health seeking attitude and adherence to therapy by tuberculosis patients from an urban slum in lagos Nigeria.

PubMed

Olayemi, S O; Oreagba, I A; Akinyede, A; Adepoju, G E

2009-12-01

Community based participation has been advocated by a number of international health organisations including the World Health Organization (WHO) as a solution to the problems of poor patient adherence and default from Directly Observed Treatment Short course [DOTs] programmes for tuberculosis control. To determine the impact of a health educational intervention on the management of tuberculosis in relation to the outcome and adherence to therapy by Tuberculosis patients residing in a densely populated urban slum in Lagos, Nigeria. The study was conducted using forty tuberculosis patients (confirmed by acid fast bacilli positive sputum), and selected randomly from those who attend the Mainland Hospital in Lagos. They were divided into two groups of twenty each made up of those to be provided with education intervention at the community level and the control groups followed up at the hospital level only. An initial assessment of the knowledge about tuberculosis management was done through a structured questionnaire for both groups. This was followed by continuous health talks for intervention group in form of neighbourhood self help approach. The results showed that the intervention had a significant impact on the understanding of disease and its management (X(2) =11.842 p<0.05), DOTS and increased awareness (X(2) =17.289 p<0.05, X(2) =10.461 p<0.05), knowing the side effects of anti-TB drugs (X(2) =10.157 p<0.05), the meaning of resistance to anti-Tuberculosis drugs (X(2) =19.798 p<0.05, X(2) =11.192 p<0.05) and importance of contact tracing (X(2) =32.4 p<0.05, X(2) =3.360 p<0.05). An effective health education is therefore beneficial for TB control in Nigeria.

LAGOS-NE: a multi-scaled geospatial and temporal database of lake ecological context and water quality for thousands of US lakes.

PubMed

Soranno, Patricia A; Bacon, Linda C; Beauchene, Michael; Bednar, Karen E; Bissell, Edward G; Boudreau, Claire K; Boyer, Marvin G; Bremigan, Mary T; Carpenter, Stephen R; Carr, Jamie W; Cheruvelil, Kendra S; Christel, Samuel T; Claucherty, Matt; Collins, Sarah M; Conroy, Joseph D; Downing, John A; Dukett, Jed; Fergus, C Emi; Filstrup, Christopher T; Funk, Clara; Gonzalez, Maria J; Green, Linda T; Gries, Corinna; Halfman, John D; Hamilton, Stephen K; Hanson, Paul C; Henry, Emily N; Herron, Elizabeth M; Hockings, Celeste; Jackson, James R; Jacobson-Hedin, Kari; Janus, Lorraine L; Jones, William W; Jones, John R; Keson, Caroline M; King, Katelyn B S; Kishbaugh, Scott A; Lapierre, Jean-Francois; Lathrop, Barbara; Latimore, Jo A; Lee, Yuehlin; Lottig, Noah R; Lynch, Jason A; Matthews, Leslie J; McDowell, William H; Moore, Karen E B; Neff, Brian P; Nelson, Sarah J; Oliver, Samantha K; Pace, Michael L; Pierson, Donald C; Poisson, Autumn C; Pollard, Amina I; Post, David M; Reyes, Paul O; Rosenberry, Donald O; Roy, Karen M; Rudstam, Lars G; Sarnelle, Orlando; Schuldt, Nancy J; Scott, Caren E; Skaff, Nicholas K; Smith, Nicole J; Spinelli, Nick R; Stachelek, Joseph J; Stanley, Emily H; Stoddard, John L; Stopyak, Scott B; Stow, Craig A; Tallant, Jason M; Tan, Pang-Ning; Thorpe, Anthony P; Vanni, Michael J; Wagner, Tyler; Watkins, Gretchen; Weathers, Kathleen C; Webster, Katherine E; White, Jeffrey D; Wilmes, Marcy K; Yuan, Shuai

2017-12-01

Understanding the factors that affect water quality and the ecological services provided by freshwater ecosystems is an urgent global environmental issue. Predicting how water quality will respond to global changes not only requires water quality data, but also information about the ecological context of individual water bodies across broad spatial extents. Because lake water quality is usually sampled in limited geographic regions, often for limited time periods, assessing the environmental controls of water quality requires compilation of many data sets across broad regions and across time into an integrated database. LAGOS-NE accomplishes this goal for lakes in the northeastern-most 17 US states.LAGOS-NE contains data for 51 101 lakes and reservoirs larger than 4 ha in 17 lake-rich US states. The database includes 3 data modules for: lake location and physical characteristics for all lakes; ecological context (i.e., the land use, geologic, climatic, and hydrologic setting of lakes) for all lakes; and in situ measurements of lake water quality for a subset of the lakes from the past 3 decades for approximately 2600-12 000 lakes depending on the variable. The database contains approximately 150 000 measures of total phosphorus, 200 000 measures of chlorophyll, and 900 000 measures of Secchi depth. The water quality data were compiled from 87 lake water quality data sets from federal, state, tribal, and non-profit agencies, university researchers, and citizen scientists. This database is one of the largest and most comprehensive databases of its type because it includes both in situ measurements and ecological context data. Because ecological context can be used to study a variety of other questions about lakes, streams, and wetlands, this database can also be used as the foundation for other studies of freshwaters at broad spatial and ecological scales. © The Author 2017. Published by Oxford University Press.

LAGOS-NE: a multi-scaled geospatial and temporal database of lake ecological context and water quality for thousands of US lakes

PubMed Central

Bacon, Linda C; Beauchene, Michael; Bednar, Karen E; Bissell, Edward G; Boudreau, Claire K; Boyer, Marvin G; Bremigan, Mary T; Carpenter, Stephen R; Carr, Jamie W; Christel, Samuel T; Claucherty, Matt; Conroy, Joseph D; Downing, John A; Dukett, Jed; Filstrup, Christopher T; Funk, Clara; Gonzalez, Maria J; Green, Linda T; Gries, Corinna; Halfman, John D; Hamilton, Stephen K; Hanson, Paul C; Henry, Emily N; Herron, Elizabeth M; Hockings, Celeste; Jackson, James R; Jacobson-Hedin, Kari; Janus, Lorraine L; Jones, William W; Jones, John R; Keson, Caroline M; King, Katelyn B S; Kishbaugh, Scott A; Lathrop, Barbara; Latimore, Jo A; Lee, Yuehlin; Lottig, Noah R; Lynch, Jason A; Matthews, Leslie J; McDowell, William H; Moore, Karen E B; Neff, Brian P; Nelson, Sarah J; Oliver, Samantha K; Pace, Michael L; Pierson, Donald C; Poisson, Autumn C; Pollard, Amina I; Post, David M; Reyes, Paul O; Rosenberry, Donald O; Roy, Karen M; Rudstam, Lars G; Sarnelle, Orlando; Schuldt, Nancy J; Scott, Caren E; Smith, Nicole J; Spinelli, Nick R; Stachelek, Joseph J; Stanley, Emily H; Stoddard, John L; Stopyak, Scott B; Stow, Craig A; Tallant, Jason M; Thorpe, Anthony P; Vanni, Michael J; Wagner, Tyler; Watkins, Gretchen; Weathers, Kathleen C; Webster, Katherine E; White, Jeffrey D; Wilmes, Marcy K; Yuan, Shuai

2017-01-01

Abstract Understanding the factors that affect water quality and the ecological services provided by freshwater ecosystems is an urgent global environmental issue. Predicting how water quality will respond to global changes not only requires water quality data, but also information about the ecological context of individual water bodies across broad spatial extents. Because lake water quality is usually sampled in limited geographic regions, often for limited time periods, assessing the environmental controls of water quality requires compilation of many data sets across broad regions and across time into an integrated database. LAGOS-NE accomplishes this goal for lakes in the northeastern-most 17 US states. LAGOS-NE contains data for 51 101 lakes and reservoirs larger than 4 ha in 17 lake-rich US states. The database includes 3 data modules for: lake location and physical characteristics for all lakes; ecological context (i.e., the land use, geologic, climatic, and hydrologic setting of lakes) for all lakes; and in situ measurements of lake water quality for a subset of the lakes from the past 3 decades for approximately 2600–12 000 lakes depending on the variable. The database contains approximately 150 000 measures of total phosphorus, 200 000 measures of chlorophyll, and 900 000 measures of Secchi depth. The water quality data were compiled from 87 lake water quality data sets from federal, state, tribal, and non-profit agencies, university researchers, and citizen scientists. This database is one of the largest and most comprehensive databases of its type because it includes both in situ measurements and ecological context data. Because ecological context can be used to study a variety of other questions about lakes, streams, and wetlands, this database can also be used as the foundation for other studies of freshwaters at broad spatial and ecological scales. PMID:29053868

LAGOS-NE: a multi-scaled geospatial and temporal database of lake ecological context and water quality for thousands of US lakes

USGS Publications Warehouse

Soranno, Patricia A.; Bacon, Linda C.; Beauchene, Michael; Bednar, Karen E.; Bissell, Edward G.; Boudreau, Claire K.; Boyer, Marvin G.; Bremigan, Mary T.; Carpenter, Stephen R.; Carr, Jamie W.; Cheruvelil, Kendra S.; Christel, Samuel T.; Claucherty, Matt; Collins, Sarah M.; Conroy, Joseph D.; Downing, John A.; Dukett, Jed; Fergus, C. Emi; Filstrup, Christopher T.; Funk, Clara; Gonzalez, Maria J.; Green, Linda T.; Gries, Corinna; Halfman, John D.; Hamilton, Stephen K.; Hanson, Paul C.; Henry, Emily N.; Herron, Elizabeth M.; Hockings, Celeste; Jackson, James R.; Jacobson-Hedin, Kari; Janus, Lorraine L.; Jones, William W.; Jones, John R.; Keson, Caroline M.; King, Katelyn B.S.; Kishbaugh, Scott A.; Lapierre, Jean-Francois; Lathrop, Barbara; Latimore, Jo A.; Lee, Yuehlin; Lottig, Noah R.; Lynch, Jason A.; Matthews, Leslie J.; McDowell, William H.; Moore, Karen E.B.; Neff, Brian; Nelson, Sarah J.; Oliver, Samantha K.; Pace, Michael L.; Pierson, Donald C.; Poisson, Autumn C.; Pollard, Amina I.; Post, David M.; Reyes, Paul O.; Rosenberry, Donald; Roy, Karen M.; Rudstam, Lars G.; Sarnelle, Orlando; Schuldt, Nancy J.; Scott, Caren E.; Skaff, Nicholas K.; Smith, Nicole J.; Spinelli, Nick R.; Stachelek, Joseph J.; Stanley, Emily H.; Stoddard, John L.; Stopyak, Scott B.; Stow, Craig A.; Tallant, Jason M.; Tan, Pang-Ning; Thorpe, Anthony P.; Vanni, Michael J.; Wagner, Tyler; Watkins, Gretchen; Weathers, Kathleen C.; Webster, Katherine E.; White, Jeffrey D.; Wilmes, Marcy K.; Yuan, Shuai

2017-01-01

Understanding the factors that affect water quality and the ecological services provided by freshwater ecosystems is an urgent global environmental issue. Predicting how water quality will respond to global changes not only requires water quality data, but also information about the ecological context of individual water bodies across broad spatial extents. Because lake water quality is usually sampled in limited geographic regions, often for limited time periods, assessing the environmental controls of water quality requires compilation of many data sets across broad regions and across time into an integrated database. LAGOS-NE accomplishes this goal for lakes in the northeastern-most 17 US states.LAGOS-NE contains data for 51 101 lakes and reservoirs larger than 4 ha in 17 lake-rich US states. The database includes 3 data modules for: lake location and physical characteristics for all lakes; ecological context (i.e., the land use, geologic, climatic, and hydrologic setting of lakes) for all lakes; and in situ measurements of lake water quality for a subset of the lakes from the past 3 decades for approximately 2600–12 000 lakes depending on the variable. The database contains approximately 150 000 measures of total phosphorus, 200 000 measures of chlorophyll, and 900 000 measures of Secchi depth. The water quality data were compiled from 87 lake water quality data sets from federal, state, tribal, and non-profit agencies, university researchers, and citizen scientists. This database is one of the largest and most comprehensive databases of its type because it includes both in situ measurements and ecological context data. Because ecological context can be used to study a variety of other questions about lakes, streams, and wetlands, this database can also be used as the foundation for other studies of freshwaters at broad spatial and ecological scales.

Sc(2)MgGa(2) and Y(2)MgGa(2).

PubMed

Sahlberg, Martin; Andersson, Yvonne

2009-03-01

Scandium magnesium gallide, Sc(2)MgGa(2), and yttrium magnesium gallide, Y(2)MgGa(2), were synthesized from the corresponding elements by heating under an argon atmosphere in an induction furnace. These intermetallic compounds crystallize in the tetragonal Mo(2)FeB(2)-type structure. All three crystallographically unique atoms occupy special positions and the site symmetries of (Sc/Y, Ga) and Mg are m2m and 4/m, respectively. The coordinations around Sc/Y, Mg and Ga are pentagonal (Sc/Y), tetragonal (Mg) and triangular (Ga) prisms, with four (Mg) or three (Ga) additional capping atoms leading to the coordination numbers [10], [8+4] and [6+3], respectively. The crystal structure of Sc(2)MgGa(2 )was determined from single-crystal diffraction intensities and the isostructural Y(2)MgGa(2) was identified from powder diffraction data.

Knowledge of commercial bus drivers about road safety measures in Lagos, Nigeria.

PubMed

Okafor Ifeoma, P; Odeyemi Kofoworola, A; Dolapo Duro, C

2013-01-01

Road traffic injuries have persisted as a serious public health problem and much of the health burden is in developing countries. Over-speeding, poor enforcement of traffic regulations and commuter buses have been highly implicated in road traffic injuries in developing countries. The aim of this study was to determine drivers' knowledge of selected road safety measures, i.e. the pre-requisites for driver's license, road signs and speed limits. This was a cross-sectional study carried out in Lagos, Nigeria. Simple random sampling was used to select the two motor parks used for the study and all the consenting commercial minibus drivers operating within the parks (407) were included in the study. Data was collected with a pre-tested, structured, interviewer-administered questionnaire and analyzed with epi-info statistical software. Two hundred and sixty-one (64.1%) of them knew that Visual Acuity test should be done before obtaining driver's license and 53.8% knew the correct minimum age for obtaining driver's license. Only 1% of the drivers had correct knowledge of the driver's license authorities in Nigeria. The drivers had poor knowledge of road signs (59.0%) and poor knowledge of maximum speed limits (100%). The oldest, least educated and least experienced drivers had the poorest level of knowledge. The drivers demonstrated poor knowledge of road safety measures. There is need for driver education to improve their knowledge.

Exposure to media content and sexual health behaviour among adolescents in Lagos metropolis, Nigeria.

PubMed

Wusu, Onipede

2013-06-01

The influence of adolescents' exposure to sexual health content of mass media in their sexual health behaviour in Nigeria is still not clear. Data were gathered through a survey conducted among adolescents aged 12-19 years in Lagos metropolis between November 2009 and February 2010. A multistage sampling strategy was adopted in selecting respondents. Logistic regression technique was utilised in the analysis. The results indicate that the respondents were most frequently exposed to TV (male = 92.2; female = 94.9) and radio (male = 88.2; female = 91.7) media. The odds ratios indicate that sexual health content of mass media significantly predicted condom use, multiple sexual relationship, sexual intercourse and self reported occurrence of abortion in the study sample. The findings imply that positive media sexual health content is likely to promote sexual health among adolescents but negative contents can put adolescents' sexual health in danger. In addition, safe sex can be advanced among adolescents if the media provide accurate information on sexuality, emphasising the dangers of risky sexual practices. Finally, this study posits that accurate portrayal of sexuality in the media would contribute immensely to improving public health in the metropolis.

Mechanical Properties of Mg2Si/Mg Composites via Powder Metallurgy Process

NASA Astrophysics Data System (ADS)

Muramatsu, Hiroshi; Kondoh, Katsuyoshi; Yuasa, Eiji; Aizawa, Tatsuhiko

The mechanical properties of the Mg2Si/Mg composites solid-state synthesized from the mixed Mg-Si powders have been investigated. The macro-hardness (HRE) and the tensile strength of the composites increase with increasing the Si content and decreasing the Si size. The particle size of the synthesized Mg2Si depends on the initial Si size; the mechanical properties of the Mg2Si/Mg composite are remarkably improved by using fine Si particles or by decreasing the grain size of Mg matrix grains when the powder mixture was prepared via bulk mechanical alloying process.

A Retrospective Study of the Health Profile of Neonates of Mothers with Anemia in Pregnancy and Pregnancy Induced Hypertension in Lagos, Nigeria

PubMed Central

Sanni, Silifat Ajoke; Onabanjo, Oluseye Olusegun; Olayiwola, Ibiyemi O.; Agbonlahor, Mure

2014-01-01

Our study assessed the health profile of neonates in relation to anemia in pregnancy and pregnancy induced hypertension (PIH). This was a retrospective study where a systematic random sampling technique was used to select a total of 1046 case records of pregnant women registered for ante-natal care at Lagos Island Maternity Hospital, Lagos, Nigeria, between 2005 and 2009. Socio-demographic characteristics of the mothers, prevalence of anemia and PIH, and neonatal health profile were obtained from the case records and were analyzed using both descriptive and inferential statistics. Pearson product moment correlation was used to show the relationship (P≤0.05) between maternal complications and neonatal health profile. Majority (68.8%) of the mothers had anemia and 6.7 % had PIH. Majority (97.12%) of the neonates were live births and 2.88% of the neonates were still births, 65.4% of the women with still birth pregnancy outcome had anemia, and 34.6% had PIH. Majority (74%) of the neonates had birth weight within normal range (2.5-4.0 kg) and majority (68%) had normal Apgar score at 5 min of birth (7-10). A positive correlation existed between the packed cell volume of the mother and the birth weight of the neonates (r=0.740, P≤0.05). A negative correlation existed between the incidence of PIH and the birth weight of the neonates (r= 0.781, P≤0.05), head circumference (r=–0.491, P≤0.05) and the length of the neonates(r=–0.480, P≤0.05). We conclude that nutritional and health care intervention programmes for pregnant women should be intensified especially during ante-natal visits to hospitals. PMID:28299124

Mg Incorporation Efficiency in Pulsed MOCVD of N-Polar GaN:Mg

NASA Astrophysics Data System (ADS)

Marini, Jonathan; Mahaboob, Isra; Hogan, Kasey; Novak, Steve; Bell, L. D.; Shahedipour-Sandvik, F.

2017-10-01

We report on the effect of growth polarity and pulsed or δ -doped growth mode on impurity incorporation in metalorganic chemical vapor deposition-grown GaN. In Ga-polar orientation, up to 12× enhancement in Mg concentration for given Mg flow rate is observed, resulting in enhanced p-type conductivity for these samples. In contrast, this enhancement effect is greatly diminished for N-polar samples, falling off with increasing Mg flow and showing maximum enhancement of 2.7× at 30 nmol/min Mg flow. At higher Mg flow rates, Mg incorporation at normal levels did not correspond to p-type conductivity, which may be due to Mg incorporation at nonacceptor sites. Concentrations of C, O, and Si were also investigated, revealing dependence on Mg flow in N-polar pulsed samples. Carbon incorporation was found to decrease with increasing Mg flow, and oxygen incorporation was found to remain high across varied Mg flow. These effects combine to result in N-polar samples that are not p-type when using the pulsed growth mode.

A geochemical and sedimentary record of high southern latitude Holocene climate evolution from Lago Fagnano, Tierra del Fuego

NASA Astrophysics Data System (ADS)

Moy, Christopher M.; Dunbar, Robert B.; Guilderson, Thomas P.; Waldmann, Nicolas; Mucciarone, David A.; Recasens, Cristina; Ariztegui, Daniel; Austin, James A.; Anselmetti, Flavio S.

2011-02-01

Situated at the southern margin of the hemispheric westerly wind belt and immediately north of the Antarctic Polar Frontal zone, Tierra del Fuego is well-positioned to monitor coupled changes in the ocean-atmosphere system of the high southern latitudes. Here we describe a Holocene paleoclimate record from sediment cores obtained from Lago Fagnano, a large lake in southern Tierra del Fuego at 55°S, to investigate past changes in climate related to these two important features of the global climate system. We use an AMS radiocarbon chronology for the last 8000 yr based on pollen concentrates, thereby avoiding contamination from bedrock-derived lignite. Our chronology is consistent with a tephrochronologic age date for deposits from the middle Holocene Volcán Hudson eruption. Combining bulk organic isotopic (δ13C and δ15N) and elemental (C and N) parameters with physical sediment properties allows us to better understand sediment provenance and transport mechanisms and to interpret Holocene climate and tectonic change during the last 8000 yr. Co-variability and long-term trends in C/N ratio, carbon accumulation rate, and magnetic susceptibility reflect an overall Holocene increase in the delivery of terrestrial organic and lithogenic material to the deep eastern basin. We attribute this variability to westerly wind-derived precipitation. Increased wind strength and precipitation in the late Holocene drives the Nothofagus forest eastward and enhances run-off and terrigenous inputs to the lake. Superimposed on the long-term trend are a series of abrupt 9 negative departures in C/N ratio, which constrain the presence of seismically-driven mass flow events in the record. We identify an increase in bulk δ13C between 7000 and 5000 cal yr BP that we attribute to enhanced aquatic productivity driven by warmer summer temperatures. The Lago Fagnano δ13C record shows similarities with Holocene records of sea surface temperature from the mid-latitude Chilean continental

A Geochemical and Sedimentary Record of High Southern Latitude Holocene Climate Evolution from Lago Fagnano, Tierra del Fuego

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moy, C M; Dunbar, R B; Guilderson, T P

Situated at the southern margin of the hemispheric westerly wind belt and immediately north of the Antarctic Polar Frontal zone, Tierra del Fuego is well-positioned to monitor coupled changes in the ocean-atmosphere system of the high southern latitudes. Here we describe a Holocene paleoclimate record from sediment cores obtained from Lago Fagnano, a large lake in southern Tierra del Fuego at 55{sup o}S, to investigate past changes in climate related to these two important features of the global climate system. We use an AMS radiocarbon chronology for the last 8,000 years based on pollen concentrates, thereby avoiding contamination from bedrock-derivedmore » lignite. Our chronology is consistent with a tephrochronologic age date for deposits from the middle Holocene Volcan Hudson eruption. Combining bulk organic isotopic ({delta}{sup 13}C and {delta}{sup 15}N) and elemental (C and N) parameters with physical sediment properties allow us to better understand sediment provenance and transport mechanisms and to interpret Holocene climate and tectonic change during the last 8,000 years. Co-variability and long-term trends in C/N ratio, carbon accumulation rate, and magnetic susceptibility reflect an overall Holocene increase in the delivery of terrestrial organic and lithogenic material to the deep eastern basin. We attribute this variability to westerly wind-derived precipitation. Increased wind strength and precipitation in the late Holocene drives the Nothofagus forest eastward and enhances run-off and terrigenous inputs to the lake. Superimposed on the long-term trend are a series of abrupt 9 negative departures in C/N ratio, which constrain the presence of seismically-driven mass flow events in the record. We identify an increase in bulk {delta}{sup 13}C between 7,000 and 5,000 cal yr BP that we attribute to enhanced aquatic productivity driven by warmer summer temperatures. The Lago Fagnano {delta}{sup 13}C record shows similarities with Holocene records of sea

A Holocene Record of Hydrological Fluctuations in the Northern Chilean Altiplano (Lago Chungará)

NASA Astrophysics Data System (ADS)

Valero-Garces, B. L.; Saez, A.; Pueyo, J.; Taberner, C.; Bao, R.; Schnurrenberger, D.; Myrbo, A.; Shapley, M.; Herrera, C.; Moreno-Caballud, A.; Gonzalez-Samperiz, P.; Giralt, S.; Oriol-Gibert, R.; Edwards, L.; Schwalb, A.

2004-12-01

Holocene records of moisture availability in the Central Andes and the Altiplano show contrasting and even opposite signals and time-transgressive millennial-scale climatic changes across the region, particularly between the Titicaca Basin and the Atacama Altiplano. A multiproxy study of a 13 kyr record of Lago Chungará (18° 15' S, 69° 10' W, 4520 m a.s.l.) provides new data to solve some of the paleoclimate controversies as regional moisture availability patterns during the early and mid Holocene and the onset of modern ENSO conditions. Lago Chungara originated after the emplacement of the Parinacota volcano debris avalanche that blocked the Chungará River prior to 13 cal. kyrs ago. A seismic survey and fifteen Kullenberg cores allowed a detailed 3-D reconstruction of the 8 m long sedimentary sequence. The chronological model is based on 5 AMS 14C on bulk organic matter and 3 U/Th dates on authigenic carbonates and shells. To assess the typically large (and variable) reservoir effect, we dated modern sediments and waters, and constrained the model with time markers based on a 210Pb age model for the last 150 yrs, volcanic ashes of known age, and the U/Th dates. We performed high-resolution analyses by an X-ray fluorescence core scanner and magnetic, sedimentological, mineralogical, isotopic, and biological (pollen, diatoms and ostracodes) analyses on selected cores. Statistical analyses helped to separate the volcanism from climate as the key driving forces in the hydrological and sedimentological evolution of the lake. Three main lacustrine units are identified on top of the pre Parinacota avalanche substrate. The basal unit (13 - 7.2 cal. kyrs BP) is a finely laminated diatomite. The middle unit (7.2 - 4.5 cal. kyrs BP) is banded and it is composed of diatomites and carbonate-rich layers. The diatomaceous upper unit (after 4.5 cal. kyrs BP) is banded to massive, and it contains abundant volcanic layers (lapilli, ash layers). Increased volcanic activity after

Parental determinants of offspring head circumference using a sample of patients attending a government hospital in Lagos, Nigeria.

PubMed

Taiwo, I A; Adeleye, A

2013-01-01

Head circumference at birth is an important neonatal parameter in view of its association with perinatal and postnatal morbidity and mortality. It is an indicator of brain volume and a tool for assessing the development of the central nervous system. Being a complex hereditary trait, predicting baby's head circumference from parental anthropometrics could complement the already existing ultrasonographic method of prediction. To identify the parental anthropometric determinants of baby's head circumference in Lagos, Nigeria, using a sample of patients attending a government hospital. Parental anthropometric parameters were obtained from 250 couples. The baby's head circumference was measured immediately after birth. The data were subjected to multivariate analysis. The parental variables that were most predictive of babies' head circumference were mid-parental weight, maternal height, maternal weight gain during pregnancy and maternal age. Assessment of these parental attributes can complement ultrasonographic data in predicting baby's head circumference for better perinatal outcome.

Work related stress and coping mechanisms among bankers in Lagos, Nigeria.

PubMed

Olatona, F A; Ezeobika, E N; Okafor, I P; Owoeye, O B A

2014-03-01

This study assessed knowledge, prevalence, associated factors and mechanisms of coping with stress among bankers in Lagos State. It was a descriptive cross sectional study. A two stage sampling technique was used to select two hundred and twenty seven (227) respondents. Data was collected using a structured self administered questionnaire. The analysis was done using Epi-info version 2002 software and Chi Square was used to determine association between variables at p value 0.05. Fischer's Exact test was used where Chi-square was not valid. The age range of respondents was between 20 and 49 years while the mean age was 31.3 +/- 5.0 years. Only 3.6% had good level of knowledge about stress, 42.2% had fair level while more than half of the respondents had poor level of knowledge about stress (54.3%). Majority (67.0%) of the respondents were moderately stressed while one quarter (24.7%) were highly stressed. Majority (92.4%) of the respondents used good coping mechanisms though 69.5% of the respondents also used bad coping mechanisms. A greater proportion of those who had poor knowledge about stress were stressed or highly stressed (p = 0.002). A statistically significant association was also found between the departments in the bank and level of stress of the respondents (p = 0.002). The prevalence of stress was high among the bank workers studied. It is recommended that effective stress management programmes are implemented to address the problem of stress among bank workers.

Interstellar fossil Mg-26 and its possible relationship to excess meteoritic Mg-26

NASA Technical Reports Server (NTRS)

Clayton, Donald D.

1986-01-01

A plausible scenario is advanced for explainig a linear correlation found in some solar system solids between their Mg-26/Mg-24 isotopic ratios and their Al/Mg elemental abundance ratios. This scenario involves three stages: (1) the mechanical aggregation of an average ensemble of Al-bearing dust particles that is postulated to be modestly enriched in the Al/Mg abundance ratio because the aggregated particles themselves are; (2) the extraction, perhaps but not necessarily by hot distillation, of almost all Mg, leaving an aggregate with a large Al/Mg ratio and a large Mg-26 excess; and (3) the uptake of normal ambient Mg by the resulting hot Al-rich solid as it cools in Mg-rich vapor. A linear correlation in solids between their Mg-26/Mg-24 isotopic ratio and their aluminum enrichment may be a fossil correlation inherited from interstellar dust.

Mg Content Dependence of EML-PVD Zn-Mg Coating Adhesion on Steel Strip

NASA Astrophysics Data System (ADS)

Jung, Woo Sung; Lee, Chang Wook; Kim, Tae Yeob; De Cooman, Bruno C.

2016-09-01

The effect of coating thickness and Mg concentration on the adhesion strength of electromagnetic levitation physical vapor deposited Zn-Mg alloy coatings on steel strip was investigated. The phase fraction of Zn, Mg2Zn11, and MgZn2 was determined for a coating Mg concentration in the 0 to 15 wt pct range. Coatings with a Mg content less than 5 pct consisted of an Zn and Mg2Zn11 phase mixture. The coatings showed good adhesion strength and ductile fracture behavior. Coatings with a higher Mg concentration, which consisted of a Mg2Zn11 and MgZn2 phase mixture, had a poor adhesion strength and a brittle fracture behavior. The adhesion strength of PVD Zn-Mg alloy coatings was found to be related to the pure Zn phase fraction. The effect of coating thickness on adhesion strength was found to be negligible. The microstructure of the interface between steel and Zn-Mg alloy coatings was investigated in detail by electron microscopy, electron diffraction, and atom probe tomography.

MgCu metallic glass

NASA Astrophysics Data System (ADS)

Durandurdu, Murat

2018-03-01

We generate an amorphous MgCu model using the rapid solidification of the melt through a first-principles molecular dynamics approach within a generalised gradient approximation and reveal, for the first time, its structural features and mechanical properties in details. The liquid and glassy MgCu are found to acquire slightly distinct local structures. Yet in both forms of MgCu, most Cu atoms have a tendency to form the ideal and defective icosahedrons while Mg atoms are arranged in complex configurations. The mean coordination number of Cu and Mg at 300 K is 11.31 and 13.73, respectively. The short-range order of MgCu glass is projected to be different than the known crystalline MgCu and Mg2Cu phases. The mechanical properties of MgCu glass and the CsCl-type MgCu crystal are computed and compared. On the basis of the enthalpy analyses, a possible pressure-induced crystallisation of the MgCu glass into a CsCl-type structure is proposed to occur at around 11 GPa.

Effect of Mg interlayer on perpendicular magnetic anisotropy of CoFeB films in MgO/Mg/CoFeB/Ta structure

NASA Astrophysics Data System (ADS)

Ma, Q. L.; Iihama, S.; Kubota, T.; Zhang, X. M.; Mizukami, S.; Ando, Y.; Miyazaki, T.

2012-09-01

The effects of Mg metallic interlayer on the magnetic properties of thin CoFeB films in MgO/Mg (tMg)/CoFeB (1.2 nm)/Ta structures were studied in this letter. Our experimental result shows that the CoFeB film exhibits perpendicular magnetic anisotropy (PMA) when the CoFeB and MgO layers are separated by a metallic Mg layer with a maximum thickness of 0.8 nm. The origin of PMA was discussed by considering the preferential transmission of the Δ1 symmetry preserved by the Mg interlayer in crystallized MgO/Mg/CoFeB/Ta. In addition, the thin Mg interlayer also contributes to enhancing the thermal stability and reducing the effective damping constant and coercivity of the CoFeB film.

Quasicrystal-reinforced Mg alloys.

PubMed

Kyun Kim, Young; Tae Kim, Won; Hyang Kim, Do

2014-04-01

The formation of the icosahedral phase (I-phase) as a secondary solidification phase in Mg-Zn-Y and Mg-Zn-Al base systems provides useful advantages in designing high performance wrought magnesium alloys. The strengthening in two-phase composites (I-phase + α -Mg) can be explained by dispersion hardening due to the presence of I-phase particles and by the strong bonding property at the I-phase/matrix interface. The presence of an additional secondary solidification phase can further enhance formability and mechanical properties. In Mg-Zn-Y alloys, the co-presence of I and Ca 2 Mg 6 Zn 3 phases by addition of Ca can significantly enhance formability, while in Mg-Zn-Al alloys, the co-presence of the I-phase and Mg 2 Sn phase leads to the enhancement of mechanical properties. Dynamic and static recrystallization are significantly accelerated by addition of Ca in Mg-Zn-Y alloy, resulting in much smaller grain size and more random texture. The high strength of Mg-Zn-Al-Sn alloys is attributed to the presence of finely distributed Mg 2 Sn and I-phase particles embedded in the α -Mg matrix.

Hydriding and dehydriding rates of Mg, Mg-10TaF5, and Mg-10NbF5 prepared via reactive mechanical grinding

NASA Astrophysics Data System (ADS)

Song, Myoung Youp; Kwak, Young Jun; Lee, Seong Ho; Park, Hye Ryoung

2015-01-01

In this work, TaF5 and NbF5 were chosen as additives to enhance the hydriding and dehydriding rates of Mg. Mg, Mg-10TaF5, and Mg-10NbF5 samples were prepared by reactive mechanical grinding. The hydriding and dehydriding properties of the samples were then examined. Mg-10TaF5 had the largest amount of hydrogen absorbed for 30 min and the highest initial dehydriding rate after incubation period, followed in order by Mg-10NbF5, and Mg. At 593 K under 12 bar H2 at the first cycle, Mg-10TaF5 absorbed 3.63 wt% H for 5 min and 4.53 wt% H for 30 min. At 593 K under 1.0 bar H2 at the first cycle, Mg-10TaF5 desorbed 0 wt% H for 2.5 min, 0.59 wt% H for 5 min, 3.42 wt% H for 30 min, and 4.24 wt% H for 60 min. The reactive mechanical grinding of Mg with TaF5 or NbF5 is believed to have facilitated the nucleation and to have decreased the diffusion distances of hydrogen atoms. These two effects are believed to have increased the hydriding and dehydriding rates of Mg. The MgF2 and Ta2H formed in Mg-10TaF5, and the MgF2, NbH2, and NbF3 formed in Mg-10NbF5 are considered to have enhanced both of these effects.

Profix cemented total knee replacement: a 5-year outcome review from Lagos, Nigeria.

PubMed

Ugbeye, M E; Odunubi, O O; Dim, E M; Ekundayo, O O

2012-01-01

Total knee replacement is a standard treatment for severe osteoarthritis of the knees. It is however, still a novel procedure in Nigeria. Literature on the procedure and outcome of management are sparse in Nigeria. This study aimed at describing Total Knee prosthetic Replacement as it is practiced in National Orthopaedic Hospital, Lagos. Data on patients treated with Total knee replacement between 2006 and 2010 were analyzed retrospectively. The standard anterior approach, with a medial parapatellar incision under pneumatic tourniquet was used in all cases. There were a total of 59 knees in 48 patients operated, with a female: male ratio of 5:1. Patients were in the sixth to ninth decades of life. There was a statistically significant relationship between duration of symptoms and severity of angular deformity. The average pre-operative Knee score (KS) was 27 and average function score (FS) was 43. Average duration of surgery was 126.38 minutes. Tourniquet removal after wound closure was associated with reduced intra-operative blood loss (p < 0.05). Post-operative complications included peri-prosthetic fracture (1.69%), post-operative anaemia (8.47%), superficial wound dehiscence (3.39%) and foot drop (3.39%). The mean post-operative KS and FS increased to 80 and 75 respectively. Total knee replacement, though a novel procedure in our institution is beneficial to patients with severe osteoarthritis. A long term outcome study is being planned.

Lake-level stratigraphy and geochronology revisited at Lago (Lake) Cardiel, Argentina, and changes in the Southern Hemispheric Westerlies over the last 25 ka

NASA Astrophysics Data System (ADS)

Quade, J.; Kaplan, M. R.

2017-12-01

Paleoshorelines around Lago (Lake) Cardiel in southern Argentina (S48.9°, W71.3°; ∼275 m) record substantial changes in lake area over the past 25 ka. Our results combined with previous research show that during the last glacial maximum (or LGM, 23-21 ka), the lake stood at near modern levels, but had nearly dried up by ∼13 ka. Between 11.3 and 10.1 ka the lake reached its highest point (+54-58 m) and greatest extent in at least the last 40 ka. Lake levels dropped thereafter and experienced two lower-lake periods: 8.5-7.5 ka and 5-3.3 ka; and two higher-lake periods: 7.4-6 and ∼5.2 ka. In the last 3.5 ka, the lake has remained generally near or slightly above its present level. The depth and surface area of Lago Cardiel are controlled mainly by precipitation onto the lake and surrounding catchment, air and water temperature, and wind-speed related to local strength of the Southern Hemispheric Westerlies (SHW). Our lake-level reconstruction combined with evidence from other studies suggest that on average the core of the SHW was located well to the north (<45°S) of the Cardiel basin during the deep lake phase associated with the LGM, and was well to the south (>55°S?) during the hydrologic maximum of Cardiel in the early Holocene. The lower phases of the lake at 20.0-11.5, 8.5-7.5, and 5.0-3.3 ka generally correspond to cold conditions in other records, when we infer that the SHW were strongly focused around the latitudes of Cardiel at 49°S.

Prevalence of cardiovascular risk factors amongst traders in an urban market in Lagos, Nigeria.

PubMed

Odugbemi, T O; Onajole, A T; Osibogun, A O

2012-03-01

A descriptive cross-sectional study was carried out to determine the prevalence of cardiovascular risk factors amongst traders in an urban market in Lagos State. Tejuosho market, one of the large popular markets was selected from a list of markets that met the inclusion criteria of being major markets dealing in general goods using a simple random sampling technique by balloting. Four hundred (400) traders were selected using a systematic random sampling. Each trader was interviewed with a well-structured questionnaire and had blood pressure and anthropometric measurements (height, weight and body mass index). Female traders made up (74.3%) 297 of the total population. The mean age was 45.48+11.88 and 42.29+10.96 years for males and females respectively. Majority 239 (59.8%) fell within the age range of 35 - 55 years. The cardiovascular risk factors identified and their prevalence rates were hypertension (34.8%), physical inactivity (92%), previously diagnosed diabetes mellitus (0.8%), risky alcohol consumption (1%), cigarette smoking (0.3%) in females and (17.5%) in males, obesity (12.3%) and overweight (39.9%). The study recommended that any health promoting, preventive or intervention programme for this population would have to be worked into their market activities if it is to make an impact.

The Influence of MgH2 on the Assessment of Electrochemical Data to Predict the Degradation Rate of Mg and Mg Alloys

PubMed Central

Mueller, Wolf-Dieter; Hornberger, Helga

2014-01-01

Mg and Mg alloys are becoming more and more of interest for several applications. In the case of biomaterial applications, a special interest exists due to the fact that a predictable degradation should be given. Various investigations were made to characterize and predict the corrosion behavior in vitro and in vivo. Mostly, the simple oxidation of Mg to Mg2+ ions connected with adequate hydrogen development is assumed, and the negative difference effect (NDE) is attributed to various mechanisms and electrochemical results. The aim of this paper is to compare the different views on the corrosion pathway of Mg or Mg alloys and to present a neglected pathway based on thermodynamic data as a guideline for possible reactions combined with experimental observations of a delay of visible hydrogen evolution during cyclic voltammetry. Various reaction pathways are considered and discussed to explain these results, like the stability of the Mg+ intermediate state, the stability of MgH2 and the role of hydrogen overpotential. Finally, the impact of MgH2 formation is shown as an appropriate base for the prediction of the degradation behavior and calculation of the corrosion rate of Mg and Mg alloys. PMID:24972140

A study on job satisfaction among clinical and non-clinical hospital staff in a teaching hospital in Lagos, Nigeria.

PubMed

Coker, O O; Coker, A O; Onuoha, B

2011-12-01

Previous studies had demonstrated that continuous and effective productivity of hospital staff are linked to job satisfaction and only those who are satisfied with their job can be maximally effective and productive. This cross-sectional descriptive survey was designed to determine the levels of job satisfaction among various groups of health care professionals working in a teaching hospital in Lagos, Nigeria. Two hundred clinical and non-clinical hospital staff were invited to take part in the study. They completed a sociodemographic questionnaire and the Job Descriptive Index (JDI). The results indicated that majority clinical and non-clinical staff were satisfied with their jobs as regards the parameters of the JDI compared with those not satisfied with their jobs. The government and health policy makers should continue to pay attention to boost job morale and satisfaction of medical health workers to continue to make them to be satisfied with their job.

Spontaneously intermixed Al-Mg barriers enable corrosion-resistant Mg/SiC multilayer coatings

DOE PAGES

Soufli, Regina; Fernandez-Perea, Monica; Baker, Sherry L.; ...

2012-07-24

Magnesium/silicon carbide (Mg/SiC) has the potential to be the best-performing reflective multilayercoating in the 25–80 nm wavelength region but suffers from Mg-related corrosion, an insidious problem which completely degrades reflectance. We have elucidated the origins and mechanisms of corrosion propagation within Mg/SiC multilayers. Based on our findings, we have demonstrated an efficient and simple-to-implement corrosion barrier for Mg/SiC multilayers. In conclusion, the barrier consists of nanometer-scale Mg and Al layers that intermix spontaneously to form a partially amorphous Al-Mg layer and is shown to prevent atmospheric corrosion while maintaining the unique combination of favorable Mg/SiC reflective properties.

Mechanical Properties of Mg-Gd and Mg-Y Solid Solutions

NASA Astrophysics Data System (ADS)

Kula, Anna; Jia, Xiaohui; Mishra, Raj K.; Niewczas, Marek

2016-12-01

The mechanical properties of Mg-Gd and Mg-Y solid solutions have been studied under uniaxial tension and compression between 4 K and 298 K (-269 °C and 25 °C). The results reveal that Mg-Gd alloys exhibit higher strength and ductility under tension and compression attributed to the more effective solid solution strengthening and grain-boundary strengthening effects. Profuse twinning has been observed under compression, resulting in a material texture with strong dominance of basal component parallel to compression axis. Under tension, twining is less active and the texture evolution is controlled mostly by slip. The alloys exhibit pronounced yield stress asymmetry and significantly different work-hardening behavior under tension and compression. Increasing of Gd and/or Y concentration leads to the reduction of the tension-compression asymmetry due to the weakening of the recrystallization texture and more balanced twinning and slip activity during plastic deformation. The results suggest that under compression of Mg-Y alloys slip is more active than twinning in comparison to Mg-Gd alloys.

Late Holocene environmental changes recorded in the sediments of Lago Thompson, Northern Chilean Patagonia

NASA Astrophysics Data System (ADS)

Fagel, Nathalie; Nuttin, Laurence; Bertrand, Sébastien; Borgniet, Geoffrey; Schmidt, Sabine; Araneda, Alberto; Torrejon, Fernando; Urrutia, Roberto

2010-05-01

We investigate the sedimentary record of Lago Thompson, a small lake (area 1.1 km2, watershed ~8 km2) located at an elevation of 750 masl in Northern Chilean Patagonia (45.38 °S, 71.47°W). At Present, the climate conditions around the lake are relatively dry, with annual precipitation averaging 500 mm. The goal of this study is to evaluate the natural climate variability over the Last Millennium in Northern Chilean Patagonia and its impact on the environment. The coring site was selected after a bathymetric survey using an echo-sounder. Several short cores were retrieved in 2008 using an Uwitec gravity corer: the length of the cores ranges between 124 and 132 cm. The preliminary age model is based on 4 AMS radiocarbon ages measured on bulk sediment and organic macro-remains. The radiocarbon ages demonstrate that the sediment cores cover the last 850 to 950 years. This sediment record, which is characterized by accumulation rates ranging between 1 and 3 mm/yr, can therefore be studied at decennial to centennial resolution. To reconstruct past changes in climate and the environment, we conducted a multiproxy study combining sedimentological, mineralogical and geochemical analyses (LOI 105, 550 and 950°C, biogenic silica content, magnetic susceptibility, tephrostratigraphy, bulk organic geochemistry, bulk mineralogy by X-ray diffraction, and inorganic geochemistry by ITRAX core scanner and ICP-AES). Visual descriptions and X-ray radiographies demonstrate that the sediment record is relatively undisturbed. The sediment is composed of light brown organic-rich clayey material. The lower part of the core (below 75 cm) is finely laminated whereas the upper part is more homogeneous. Magnetic susceptibility values highlight two tephra layers that represent explosive eruptions of volcanoes from the southern volcanic zone of Chile (Hudson, Cay, or Macá volcanoes). The biogenic silica content of the sediment retrieved in Lago Thompson is high (40 to 80%), and probably

Holocene vegetational and coastal environmental changes from the Lago Crispim record in northeastern Pará State, eastern Amazonia.

PubMed

Behling, H; Lima da Costa, M

2001-04-01

Vegetational and coastal environmental changes have been interpreted from a 600cm long and 764014C yr B.P. old sediment core from Lago Crispim located in the northeastern Pará State in northern Brazil. The radiocarbon dated sediment core was studied by multi-element geochemistry, pollen and charcoal analysis.Holocene Atlantic sea-level rise caused an elevation of local water table, which allowed the formation of organic deposits in a probably former inter-dune valley. Dense, diverse and tall Amazon rain forest, and some restinga (coastal vegetation) covered the study area at the beginning of the record at 764014C yr B.P. Mangrove vegetation developed along rivers close to the core site at that time. Subsequent decrease in less mangrove vegetation near the study site indicates a sea-level regression, beginning since around 700014C yr B.P. Lower sea-levels probably favoured the formation of a local Mauritia/Mauritiella palm swamp at 662014C yr B.P. Oscillations of higher and lower sea-level stands probably changed the size of the local palm swamp area several times between 6620 and 363014C yr B.P. Sea-level transgression at around 363014C yr B.P., caused marked coastal environmental changes: the development of mangroves near the site, the replacement of the local palm swamp by a Cyperaceae swamp, the substitution of the surrounding former Amazon rain forest and some restinga vegetation mainly by salt marshes. High amount carbonised particles suggest a strong human impact by burning on the coastal ecosystems during this late Holocene period.Highest concentrations of NaCl and also Ca, Mg and K in the upper sediment core indicate that the Atlantic was close during the late Holocene period. The core site, which is today 500m from the coastline and only 1-2m above modern sea-level, was apparently never reached by marine excursions during the Holocene.Less representation of mangrove since ca. 184014C yr B.P., may be related due to a slightly lower sea-level or to human

Control Al/Mg intermetallic compound formation during ultrasonic-assisted soldering Mg to Al.

PubMed

Xu, Zhiwu; Li, Zhengwei; Li, Jiaqi; Ma, Zhipeng; Yan, Jiuchun

2018-09-01

To prevent the formation of Al/Mg intermetallic compounds (IMCs) of Al 3 Mg 2 and Al 12 Mg 17 , dissimilar Al/Mg were ultrasonic-assisted soldered using Sn-based filler metals. A new IMC of Mg 2 Sn formed in the soldered joints during this process and it was prone to crack at large thickness. The thickness of Mg 2 Sn was reduced to 22 μm at 285 °C when using Sn-3Cu as the filler metal. Cracks were still observed inside the blocky Mg 2 Sn. The thickness of Mg 2 Sn was significantly reduced when using Sn-9Zn as the filler metal. A 17 μm Mg 2 Sn layer without crack was obtained at a temperature of 200 °C, ultrasonic power of Mode I, and ultrasonic time of 2 s. The shear strengths of the joints using Sn-9Zn was much higher than those using Sn-3Cu because of the thinner Mg 2 Sn layer in the former joints. Sn whiskers were prevented by using Sn-9Zn. A cavitation model during ultrasonic assisted soldering was proposed. Copyright © 2018 Elsevier B.V. All rights reserved.

The millimeter-wave spectrum of the MgH and MgD radicals

NASA Technical Reports Server (NTRS)

Ziurys, L. M.; Barclay, W. L., Jr.; Anderson, M. A.

1993-01-01

The pure rotational spectrum of MgH radical (X 2 Sigma (+)) in its ground state v = 0 and v = 1 vibrational modes has been observed in the laboratory using millimeter/submillimeter direct absorption spectroscopy. The rotational spectra of two isotopically substituted species, MgD and (Mg-26)H, have been detected as well. All six hyperfine components of the N = 0 -1 transition of MgH in its v = 0 and v = 1 states have been directly measured to an accuracy of +/-50 kHz, and the five components have been observed for (Mg-26)H. The N = 0 +/-1 and N = 1 -2 transitions of MgD have also been detected. Rotational, fine structure, and hyperfine constants were determined for all species from a nonlinear least-squared fit to the data using a 2 Sigma Hamiltonian.

The Interplay of Al and Mg Speciation in Advanced Mg Battery Electrolyte Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

See, Kimberly A.; Chapman, Karena W.; Zhu, Lingyang

2016-01-13

Mg batteries are an attractive alternative to Li-based energy storage due to the possibility of higher volumetric capacities with the added advantage of using sustainable materials. A promising emerging electrolyte for Mg batteries is the magnesium aluminum chloride complex (MACC) which shows high Mg electrodeposition and stripping efficiencies and relatively high anodic stabilities. As prepared, MACC is inactive with respect to Mg deposition; however, efficient Mg electrodeposition can be achieved following an electrolytic conditioning process. Through the use of Raman spectroscopy, surface enhanced Raman spectroscopy, 27Al and 35Cl nuclear magnetic resonance spectroscopy, and pair distribution function analysis, we explore themore » active vs inactive complexes in the MACC electrolyte and demonstrate the codependence of Al and Mg speciation. These techniques report on significant changes occurring in the bulk speciation of the conditioned electrolyte relative to the as-prepared solution. Analysis shows that the active Mg complex in conditioned MACC is very likely the [Mg2(μ–Cl)3·6THF]+ complex that is observed in the solid state structure. Additionally, conditioning creates free Cl– in the electrolyte solution, and we suggest the free Cl– adsorbs at the electrode surface to enhance Mg electrodeposition.« less

Psychosocial effects of cleft lip and palate on Nigerians: the Ikeja-Lagos experience.

PubMed

Fadeyibi, Idowu O; Coker, Olurotimi A; Zacchariah, Matthiew P; Fasawe, Adedolapo; Ademiluyi, Samuel A

2012-02-01

We studied 116 patients who presented with cleft lip and palate (CLP) and were seen during a state-wide screening exercise for people with orofacial deformities in Ikeja-Lagos, Nigeria between May 2006 and July 2007. Detailed histories were taken and physical examinations made. The following psychometric instruments: General Health Questionnaire 28 (GHQ28), State-Trait Anxiety Inventory Y1 (STAI-Y1), STAI-Y2, and Self rating Depression Scale (SDS) were given on the respondents by a clinical psychologist. The respondents comprised 57 men and 59 women with a male:female ratio of 1:1.04. There were 42 (36%) adults and 74 (64%) children. Fifty-four (47%) patients had cleft lip (CL), 27 (23%) had cleft lip and palate (CLP), and 35 (30%) had cleft palate alone. Forty-five (39%) of the respondents were parents and guardians who responded to the presence of the deformity on behalf of children who were less than 6 years old, and assessed the reactions of those who were aged 6-12 years old. Older patients replied directly to the psychometric instruments. The outcome of the assessment of the Mental Health Profile of the participants showed high incidence of anxiety, depression, and impairment of general wellbeing. The effects were most pronounced in the 6-12 year age group. We recommend that the psychosocial impacts of CLP on the patients, parents, and relations should be managed together with the reconstructive procedures.

Occupational hazards and safety measures amongst the paint factory workers in lagos, Nigeria.

PubMed

Awodele, Olufunsho; Popoola, Temidayo D; Ogbudu, Bawo S; Akinyede, Akin; Coker, Herbert A B; Akintonwa, Alade

2014-06-01

The manufacture of paint involves a variety of processes that present with medical hazards. Safety initiatives are hence introduced to limit hazard exposures and promote workplace safety. This aim of this study is to assess the use of available control measures/initiatives in selected paint factories in Lagos West Senatorial District, Nigeria. A total of 400 randomly selected paint factory workers were involved in the study. A well-structured World Health Organization standard questionnaire was designed and distributed to the workers to elicit information on awareness to occupational hazards, use of personal protective devices, and commonly experienced adverse symptoms. Urine samples were obtained from 50 workers randomly selected from these 400 participants, and the concentrations of the heavy metals (lead, cadmium, arsenic, and chromium) were determined using atomic absorption spectroscopy. The results show that 72.5% of the respondents are aware of the hazards associated with their jobs; 30% have had formal training on hazards and safety measures; 40% do not use personal protective devices, and 90% of the respondents reported symptoms relating to hazard exposure. There was a statistically significant (p < 0.05) increase in the mean heavy metal concentrations in the urine samples obtained from paint factory workers as compared with nonfactory workers. The need to develop effective frameworks that will initiate the integration and ensure implementation of safety regulations in paint factories is evident. Where these exist, there is a need to promote adherence to these practice guidelines.

Factors affecting patient satisfaction at the Lagos State University Teaching Hospital Dental Clinic.

PubMed

Adeniyi, A A; Adegbite, K O; Braimoh, M O; Ogunbanjo, B O

2013-03-01

Satisfaction is important in dental care because satisfaction with care alleviates dental anxiety, influences patients' compliance and is an important indicator of quality of care. This study was designed to determine the factors that contribute to satisfaction with dental care among patients attending the Lagos State University (LASUTH) Dental Clinic. Across-sectional, descriptive questionnaire-based survey was conducted among adult patients attending the LASUTH Dental Clinic. The questionnaire, a modification of the Dental Satisfaction Questionnaire (DSQ), contained 19 items on a Likert-pattern scale with scores ranging from 0 to 4. The scores obtained for satisfaction with the dental services ranged from 19 to 75 with a mean of 55.30 +/- 11.55. The majority of respondents (305 or 87.4%) were satisfied with the services received. The items generating the highest and lowest mean satisfaction score were cleanliness/comfort of the facility and cost of services respectively. Long waiting time was the item respondents liked least about the services. There was a statistically significant relationship between the items assessing communication and respondent's gender (p = 0.001). The relationship between the overall satisfaction score and gender (p = 0.233), age category (p = 0.842) and educational status (p = 0.565) were not statistically significant. The results indicate a high level of satisfaction with services provided at the LASUTH Dental Clinic. However, there is need for improvement in communication with patients and reduction in waiting time.

Relativistic quasiparticle band structures of Mg2Si, Mg2Ge, and Mg2Sn: Consistent parameterization and prediction of Seebeck coefficients

NASA Astrophysics Data System (ADS)

Shi, Guangsha; Kioupakis, Emmanouil

2018-02-01

We apply density functional and many-body perturbation theory calculations to consistently determine and parameterize the relativistic quasiparticle band structures of Mg2Si, Mg2Ge, and Mg2Sn, and predict the Seebeck coefficient as a function of doping and temperature. The quasiparticle band gaps, including spin-orbit coupling effects, are determined to be 0.728 eV, 0.555 eV, and 0.142 eV for Mg2Si, Mg2Ge, and Mg2Sn, respectively. The inclusion of the semicore electrons of Mg, Ge, and Sn in the valence is found to be important for the accurate determination of the band gaps of Mg2Ge and Mg2Sn. We also developed a Luttinger-Kohn Hamiltonian and determined a set of band parameters to model the near-edge relativistic quasiparticle band structure consistently for all three compounds that can be applied for thermoelectric device simulations. Our calculated values for the Seebeck coefficient of all three compounds are in good agreement with the available experimental data for a broad range of temperatures and carrier concentrations. Our results indicate that quasiparticle corrections are necessary for the accurate determination of Seebeck coefficients at high temperatures at which bipolar transport becomes important.

'I don't get this climate stuff!' Making sense of climate change among the corporate middle class in Lagos.

PubMed

Asiyanbi, Adeniyi P

2015-11-01

Public engagement continues to be central to wider efforts to address climate change. This study contributes to public engagement debates by investigating engagement with climate change among an often overlooked group, the corporate middle class in Africa's second largest megacity, Lagos. Combining survey and interviews, I focus analysis on three aspects: awareness, knowledge and concern; role of scientific and social frames in shaping general attitude; and spatial attribution of causes and consequences. The study reveals a universal awareness and high concern about climate change among the respondents, although understanding and perceptions of climate change are significantly socially framed. Social situatedness, more than scientific facts, is the most important definer of overall engagement with climate change. This study thus underscores a nuanced constructionist stance, showing how corporate professionals' 'ways of knowing' climate change is underpinned by a certain co-production between scientific and socio-experiential frames. I highlight implications for research and public engagement with climate change. © The Author(s) 2015.

Radiological risk assessment of cosmic radiation at aviation altitudes (a trip from Houston Intercontinental Airport to Lagos International Airport).

PubMed

Enyinna, Paschal Ikenna

2016-01-01

Radiological risk parameters associated with aircrew members traveling from Houston Intercontinental Airport to Lagos International Airport have been computed using computer software called EPCARD (version 3.2). The mean annual effective dose of radiation was computed to be 2.94 mSv/year. This result is above the standard permissible limit of 1 mSv/year set for the public and pregnant aircrew members but below the limit set for occupationally exposed workers. The Risk of cancer mortality and excess career time cancer risk computed ranged from 3.5 × 10(-5) to 24.5 × 10(-5) (with average of 14.7 × 10(-5)) and 7 × 10(-4) to 49 × 10(-4) (with average of 29.4 × 10(-4)). Passengers and aircrew members should be aware of the extra cosmic radiation doses taken in during flights. All aircraft operators should monitor radiation doses incurred during aviation trips.

Radiological risk assessment of cosmic radiation at aviation altitudes (a trip from Houston Intercontinental Airport to Lagos International Airport)

PubMed Central

Enyinna, Paschal Ikenna

2016-01-01

Radiological risk parameters associated with aircrew members traveling from Houston Intercontinental Airport to Lagos International Airport have been computed using computer software called EPCARD (version 3.2). The mean annual effective dose of radiation was computed to be 2.94 mSv/year. This result is above the standard permissible limit of 1 mSv/year set for the public and pregnant aircrew members but below the limit set for occupationally exposed workers. The Risk of cancer mortality and excess career time cancer risk computed ranged from 3.5 × 10−5 to 24.5 × 10−5 (with average of 14.7 × 10−5) and 7 × 10−4 to 49 × 10−4 (with average of 29.4 × 10−4). Passengers and aircrew members should be aware of the extra cosmic radiation doses taken in during flights. All aircraft operators should monitor radiation doses incurred during aviation trips. PMID:27651568

Laser cooling of MgCl and MgBr in theoretical approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wan, Mingjie; Shao, Juxiang; Huang, Duohui

Ab initio calculations for three low-lying electronic states (X{sup 2}Σ{sup +}, A{sup 2}Π, and 2{sup 2}Π) of MgCl and MgBr molecules, including spin-orbit coupling, are performed using multi-reference configuration interaction plus Davidson correction method. The calculations involve all-electronic basis sets and Douglas–Kroll scalar relativistic correction. Spectroscopic parameters well agree with available theoretical and experimental data. Highly diagonally distributed Franck-Condon factors f{sub 00} for A{sup 2}Π{sub 3/2,1/2} (υ′ = 0) → X{sup 2}Σ{sup +}{sub 1/2} (υ″ = 0) are determined for both MgCl and MgBr molecules. Suitable radiative lifetimes τ of A{sup 2}Π{sub 3/2,1/2} (υ′ = 0) states for rapid lasermore » cooling are also obtained. The proposed laser drives A{sup 2}Π{sub 3/2} (υ′ = 0) → X{sup 2}Σ{sup +}{sub 1/2} (υ″ = 0) transition by using three wavelengths (main pump laser λ{sub 00}; two repumping lasers λ{sub 10} and λ{sub 21}). These results indicate the probability of laser cooling MgCl and MgBr molecules.« less

High-resolution chronology for deglaciation of the Patagonian Ice Sheet at Lago Buenos Aires (46.5°S) revealed through varve chronology and Bayesian age modelling

NASA Astrophysics Data System (ADS)

Bendle, Jacob M.; Palmer, Adrian P.; Thorndycraft, Varyl R.; Matthews, Ian P.

2017-12-01

Glaciolacustrine varves offer the potential to construct continuous, annually-resolved chronologies for ice-sheet deglaciation, and improved understanding of glacier retreat dynamics. This paper investigates laminated glaciolacustrine sediments deposited around the waning margins of the Patagonian Ice Sheet, following the local Last Glacial Maximum (LGM). Detailed macro- and microfacies analyses confirm an annual (varve) structure within these sediments. The correlation of annual layers (varves) across five sites in eastern Lago Buenos Aires yields a 994 ± 36 varve-year (vyr) chronology and thickness record. The floating chronology has been anchored to the calendar-year timescale through identification of the Ho tephra (17,378 ± 118 cal a BP) in the varve sequences. Using a Bayesian age model to integrate the new varve chronology with published moraine ages, the onset of deglaciation at 46.5°S is dated to 18,086 ± 214 cal a BP. New age estimates for deglacial events are combined with high-resolution analysis of varve thickness trends, and new lithostratigraphic data on ice-margin position(s), to reconstruct ice-margin retreat rates for the earliest ca. 1000 years of ice-sheet demise. Glacier retreat rates were moderate (5.3-10.3 m yr-1) until 17,322 ± 115 cal a BP, but subsequently accelerated (15.4-18.0 m yr-1). Sustained influxes of ice-rafted debris (IRD) after 17,145 ± 122 cal a BP suggest retreat rates were enhanced by calving after ice contracted into deeper lake waters. Ice persisted in eastern Lago Buenos Aires until at least 16,934 ± 116 cal a BP, after which the glacier started to retreat towards the Patagonian mountains.

Long-Term Survival of an Urban Fruit Bat Seropositive for Ebola and Lagos Bat Viruses

PubMed Central

Hayman, David T. S.; Emmerich, Petra; Yu, Meng; Wang, Lin-Fa; Suu-Ire, Richard; Fooks, Anthony R.; Cunningham, Andrew A.; Wood, James L. N.

2010-01-01

Ebolaviruses (EBOV) (family Filoviridae) cause viral hemorrhagic fevers in humans and non-human primates when they spill over from their wildlife reservoir hosts with case fatality rates of up to 90%. Fruit bats may act as reservoirs of the Filoviridae. The migratory fruit bat, Eidolon helvum, is common across sub-Saharan Africa and lives in large colonies, often situated in cities. We screened sera from 262 E. helvum using indirect fluorescent tests for antibodies against EBOV subtype Zaire. We detected a seropositive bat from Accra, Ghana, and confirmed this using western blot analysis. The bat was also seropositive for Lagos bat virus, a Lyssavirus, by virus neutralization test. The bat was fitted with a radio transmitter and was last detected in Accra 13 months after release post-sampling, demonstrating long-term survival. Antibodies to filoviruses have not been previously demonstrated in E. helvum. Radio-telemetry data demonstrates long-term survival of an individual bat following exposure to viruses of families that can be highly pathogenic to other mammal species. Because E. helvum typically lives in large urban colonies and is a source of bushmeat in some regions, further studies should determine if this species forms a reservoir for EBOV from which spillover infections into the human population may occur. PMID:20694141

Long-term survival of an urban fruit bat seropositive for Ebola and Lagos bat viruses.

PubMed

Hayman, David T S; Emmerich, Petra; Yu, Meng; Wang, Lin-Fa; Suu-Ire, Richard; Fooks, Anthony R; Cunningham, Andrew A; Wood, James L N

2010-08-04

Ebolaviruses (EBOV) (family Filoviridae) cause viral hemorrhagic fevers in humans and non-human primates when they spill over from their wildlife reservoir hosts with case fatality rates of up to 90%. Fruit bats may act as reservoirs of the Filoviridae. The migratory fruit bat, Eidolon helvum, is common across sub-Saharan Africa and lives in large colonies, often situated in cities. We screened sera from 262 E. helvum using indirect fluorescent tests for antibodies against EBOV subtype Zaire. We detected a seropositive bat from Accra, Ghana, and confirmed this using western blot analysis. The bat was also seropositive for Lagos bat virus, a Lyssavirus, by virus neutralization test. The bat was fitted with a radio transmitter and was last detected in Accra 13 months after release post-sampling, demonstrating long-term survival. Antibodies to filoviruses have not been previously demonstrated in E. helvum. Radio-telemetry data demonstrates long-term survival of an individual bat following exposure to viruses of families that can be highly pathogenic to other mammal species. Because E. helvum typically lives in large urban colonies and is a source of bushmeat in some regions, further studies should determine if this species forms a reservoir for EBOV from which spillover infections into the human population may occur.

The effect of a sexuality education programme among out- of- school adolescents in Lagos, Nigeria.

PubMed

Odeyemi, K A; Onajole, A T; Ogunowo, B E; Olufunlayo, T; Segun, B

2014-06-01

This study was conducted to assess the effect of a community based sexuality education programme on the sexual health knowledge and practices of out of school female adolescents. This Intervention study was conducted in two markets within Lagos, Nigeria. Representative samples of adolescents were interviewed on their sexual health knowledge and practices. An Education- entertainment programme provided sexuality education to adolescents in Mushin market only (intervention group) followed by post intervention surveys in Mushin market and Sangrouse market (control group). The pre and post intervention surveys were compared 6 months post intervention to detect any changes. Sexual health knowledge and behaviour was similar among respondents in both markets pre intervention. Post intervention, the sexual health knowledge of the respondents in the intervention site improved significantly. (p<0.05) Fewer adolescents initiated sex in the intervention site than in the control site and contraceptive use increased. However among the sexually active, there was no significant change in their condom use and number of sexual partners. Community based health education programmes can be used to provide effective sexuality education for out of school adolescents. Provision should be made by government and non-governmental organisations during adolescent reproductive health programming for sexuality education targeted at out of school adolescents.

The duration of prograde garnet crystallization in the UHP eclogites at Lago di Cignana, Italy

NASA Astrophysics Data System (ADS)

Skora, Susanne; Lapen, Thomas J.; Baumgartner, Lukas P.; Johnson, Clark M.; Hellebrand, Eric; Mahlen, Nancy J.

2009-10-01

The distinct core-to-rim zonation of different REEs in garnet in metamorphic rocks, specifically Sm relative to Lu, suggests that Sm-Nd and Lu-Hf isochron ages will record different times along a prograde garnet growth history. Therefore, REE zonations in garnet must be measured in order to correctly interpret the isochron ages in terms of the garnet growth interval, which could span several m.y. New REE profiles, garnet crystal size distributions, and garnet growth modeling, combined with previously published Sm-Nd and Lu-Hf geochronology on a UHP eclogite of the Zermatt-Saas Fee (ZSF) ophiolite, Lago di Cignana (Italy), demonstrate that prograde garnet growth of this sample occurred over a ~ 30 to 40 m.y. interval. Relative to peak metamorphism at 38 to 40 Ma, garnet growth is estimated to have begun at ~ 11 to 14 kbar pressure at ~ 70 to 80 Ma. Although such a protracted garnet growth interval is surprising, this is supported by plate tectonic reconstructions which suggest that subduction of the Liguro-Piemont ocean occurred through slow and oblique convergence. These results demonstrate that REE zonations in garnet, coupled to crystal size distributions, provide a powerful means for understanding prograde metamorphic paths when combined with Sm-Nd and Lu-Hf geochronology.

Prevalence and correlates of depressive disorders in outpatients with breast cancer in Lagos, Nigeria.

PubMed

Popoola, Abiodun O; Adewuya, Abiodun O

2012-06-01

While the physical complications of breast cancer are often recognized and well managed, the psychological sequelae, especially depression are often unrecognized by healthcare providers and therefore under treated. This study aimed to assess the rate and correlate of depressive disorders in breast cancer survivors in Lagos, Nigeria. Patients (n = 124) recruited from a breast cancer outpatient clinic were assessed for the DSM-IV diagnosis of depressive disorders using the Mini International Neuropsychiatric Interview (MINI). The staging of the cancer, length of diagnosis and treatment type were recorded. Also socio-demographic details and their perceived level of social support were obtained. Twenty-one (16.9%) were diagnosed as having Major Depressive Disorder, while 29 (23.4%) had Minor depressive disorder making a total of 50 (40.3%) cases with depression. The independent correlates of depression included being not married (odds ratio (OR) 3.09, 95% CI 1.30-7.42), perceived poor social support (OR 5.38, 95% CI 1.88-16.63) and advanced stage of the cancer (OR 3.22, 95% CI 1.32-8.26). Our study suggests a high rate of associated depression among patients with breast cancer in our environment. Clinicians should be encouraged and empowered to probe for symptoms of depression in these patient while larger hypothesis-driven studies are needed. Copyright © 2011 John Wiley & Sons, Ltd.

Bearded saki feeding strategies on an island in Lago Guri, Venezuela.

PubMed

Norconk, Marilyn A; Conklin-Brittain, Nancy L

2016-05-01

Free-ranging bearded sakis (Chiropotes spp.) live in relatively large social groups (22-65+), inhabit very large home ranges (200-1,000 ha), and travel long distances (1.8 to >7 km) each day. While these characteristics would seem to reduce their ability to occupy habitat fragments, several studies suggest otherwise. The key to their success may lie in their dietary adaptations. Bearded sakis are strongly frugivorous, but are primarily seed eaters, and are able to ingest both young and mature fruit. We examined feeding activities of a group of bearded sakis over a 19-month period on a 180 ha island in Lago Guri, Venezuela. Given their feeding adaptations, we predicted that they would minimize peaks and troughs in plant species used for food, limit seasonal variation in the mechanical properties of foods ingested, and balance ingestion of energy-rich foods (e.g. lipids, nonstructural carbohydrates (TNC), and/or free simple sugars). We found that bearded sakis on Danto Manchado had a diverse (plant-based) diet, but two resources (Pradosia caracasana, Sapotaceae, and Oryctanthus alveolatus, Loranthaceae) provided a stable dietary base and were present in the diet almost every month. Second, we found little variation in the mechanical-resistance properties of fruits opened seasonally. Third, they alternated months ingesting foods with high TNC content and months of high lipid content. This may be an attempt to balance energy intake from available foods. Finally, their social propensity to split up into subgroups may predispose them to reduce group sizes to accommodate smaller available areas. We suggest that bearded sakis use both ecological and behavioral mechanisms to survive in smaller-than-typical areas. Longer-term studies (beyond a few generations) of bearded sakis in habitat fragments would allow us to estimate minimum survival area and identify critical resources or resource combinations. © 2015 Wiley Periodicals, Inc.

Head circumference of children with sickle cell disease in Lagos, Nigeria.

PubMed

Senbanjo, Idowu Odunayo; Oshikoya, Kazeem Adeola; Salisu, Mohammed; Diaku-Akinwumi, Ijeoma Nnenna

2016-01-01

Growth retardation and under-nutrition are common in children with sickle cell disease (SCD). The aim of this study was to compare the head circumference (HC) of SCD children and non-SCD children and to determine the effect of malnutrition on head circumference of children with SCD. This was a prospective case-control study conducted at the Lagos State University Teaching Hospital, Nigeria, involving SCD children (subject, n = 118) and non-SCD children (control, n = 118) matched for age, sex, and socioeconomic status. Weight, height and HC were measured using standard techniques. The mean ages of children with and without SCD were 7.46 ± 3.69 years and 7.01 ± 3.58 years, respectively. The HC increased significantly with age in both males and females (r = 0.75, p = < 0.001; r = 0.70, p < 0.001 respectively). There was no significant difference in HC between males and females (p > 0.05). At all ages, the mean head circumference of SCD children was not significantly (p > 0.05) different from non-SCD children. The In the age group 11-15 years, the prevalence of stunting was significantly higher among SCD children than non-SCD children. The mean HC of SCD children with stunting was significantly lower than those not stunted (51.7 vs. 53.5; P= 0.006) in age group 11.15 years. The head circumference of children with SCD is not significantly different from that of non-SCD children. Therefore, the HC chart for the general population is also applicable for monitoring head growth in children with SCD. The effect of malnutrition on head circumference of SCD children is most marked in age group 11-15 years.

Head circumference of children with sickle cell disease in Lagos, Nigeria

PubMed Central

Senbanjo, Idowu Odunayo; Oshikoya, Kazeem Adeola; Salisu, Mohammed; Diaku-Akinwumi, Ijeoma Nnenna

2016-01-01

Introduction Growth retardation and under-nutrition are common in children with sickle cell disease (SCD). The aim of this study was to compare the head circumference (HC) of SCD children and non-SCD children and to determine the effect of malnutrition on head circumference of children with SCD. Methods This was a prospective case-control study conducted at the Lagos State University Teaching Hospital, Nigeria, involving SCD children (subject, n = 118) and non-SCD children (control, n = 118) matched for age, sex, and socioeconomic status. Weight, height and HC were measured using standard techniques. Results The mean ages of children with and without SCD were 7.46 ± 3.69 years and 7.01 ± 3.58 years, respectively. The HC increased significantly with age in both males and females (r = 0.75, p = < 0.001; r = 0.70, p < 0.001 respectively). There was no significant difference in HC between males and females (p > 0.05). At all ages, the mean head circumference of SCD children was not significantly (p > 0.05) different from non-SCD children. The In the age group 11-15 years, the prevalence of stunting was significantly higher among SCD children than non-SCD children. The mean HC of SCD children with stunting was significantly lower than those not stunted (51.7 vs. 53.5; P= 0.006) in age group 11.15 years. Conclusion The head circumference of children with SCD is not significantly different from that of non-SCD children. Therefore, the HC chart for the general population is also applicable for monitoring head growth in children with SCD. The effect of malnutrition on head circumference of SCD children is most marked in age group 11-15 years. PMID:28154697

Pathogenesis of bat rabies in a natural reservoir: Comparative susceptibility of the straw-colored fruit bat (Eidolon helvum) to three strains of Lagos bat virus.

PubMed

Suu-Ire, Richard; Begeman, Lineke; Banyard, Ashley C; Breed, Andrew C; Drosten, Christian; Eggerbauer, Elisa; Freuling, Conrad M; Gibson, Louise; Goharriz, Hooman; Horton, Daniel L; Jennings, Daisy; Kuzmin, Ivan V; Marston, Denise; Ntiamoa-Baidu, Yaa; Riesle Sbarbaro, Silke; Selden, David; Wise, Emma L; Kuiken, Thijs; Fooks, Anthony R; Müller, Thomas; Wood, James L N; Cunningham, Andrew A

2018-03-01

Rabies is a fatal neurologic disease caused by lyssavirus infection. People are infected through contact with infected animals. The relative increase of human rabies acquired from bats calls for a better understanding of lyssavirus infections in their natural hosts. So far, there is no experimental model that mimics natural lyssavirus infection in the reservoir bat species. Lagos bat virus is a lyssavirus that is endemic in straw-colored fruit bats (Eidolon helvum) in Africa. Here we compared the susceptibility of these bats to three strains of Lagos bat virus (from Senegal, Nigeria, and Ghana) by intracranial inoculation. To allow comparison between strains, we ensured the same titer of virus was inoculated in the same location of the brain of each bat. All bats (n = 3 per strain) were infected, and developed neurological signs, and fatal meningoencephalitis with lyssavirus antigen expression in neurons. There were three main differences among the groups. First, time to death was substantially shorter in the Senegal and Ghana groups (4 to 6 days) than in the Nigeria group (8 days). Second, each virus strain produced a distinct clinical syndrome. Third, the spread of virus to peripheral tissues, tested by hemi-nested reverse transcriptase PCR, was frequent (3 of 3 bats) and widespread (8 to 10 tissues positive of 11 tissues examined) in the Ghana group, was frequent and less widespread in the Senegal group (3/3 bats, 3 to 6 tissues positive), and was rare and restricted in the Nigeria group (1/3 bats, 2 tissues positive). Centrifugal spread of virus from brain to tissue of excretion in the oral cavity is required to enable lyssavirus transmission. Therefore, the Senegal and Ghana strains seem most suitable for further pathogenesis, and for transmission, studies in the straw-colored fruit bat.

Pathogenesis of bat rabies in a natural reservoir: Comparative susceptibility of the straw-colored fruit bat (Eidolon helvum) to three strains of Lagos bat virus

PubMed Central

Suu-Ire, Richard; Banyard, Ashley C.; Breed, Andrew C.; Drosten, Christian; Eggerbauer, Elisa; Freuling, Conrad M.; Gibson, Louise; Goharriz, Hooman; Horton, Daniel L.; Jennings, Daisy; Kuzmin, Ivan V.; Marston, Denise; Ntiamoa-Baidu, Yaa; Riesle Sbarbaro, Silke; Selden, David; Wise, Emma L.; Kuiken, Thijs; Fooks, Anthony R.; Müller, Thomas; Wood, James L. N.; Cunningham, Andrew A.

2018-01-01

Rabies is a fatal neurologic disease caused by lyssavirus infection. People are infected through contact with infected animals. The relative increase of human rabies acquired from bats calls for a better understanding of lyssavirus infections in their natural hosts. So far, there is no experimental model that mimics natural lyssavirus infection in the reservoir bat species. Lagos bat virus is a lyssavirus that is endemic in straw-colored fruit bats (Eidolon helvum) in Africa. Here we compared the susceptibility of these bats to three strains of Lagos bat virus (from Senegal, Nigeria, and Ghana) by intracranial inoculation. To allow comparison between strains, we ensured the same titer of virus was inoculated in the same location of the brain of each bat. All bats (n = 3 per strain) were infected, and developed neurological signs, and fatal meningoencephalitis with lyssavirus antigen expression in neurons. There were three main differences among the groups. First, time to death was substantially shorter in the Senegal and Ghana groups (4 to 6 days) than in the Nigeria group (8 days). Second, each virus strain produced a distinct clinical syndrome. Third, the spread of virus to peripheral tissues, tested by hemi-nested reverse transcriptase PCR, was frequent (3 of 3 bats) and widespread (8 to 10 tissues positive of 11 tissues examined) in the Ghana group, was frequent and less widespread in the Senegal group (3/3 bats, 3 to 6 tissues positive), and was rare and restricted in the Nigeria group (1/3 bats, 2 tissues positive). Centrifugal spread of virus from brain to tissue of excretion in the oral cavity is required to enable lyssavirus transmission. Therefore, the Senegal and Ghana strains seem most suitable for further pathogenesis, and for transmission, studies in the straw-colored fruit bat. PMID:29505617

Hydrogen sorption in Pd-decorated Mg-MgO core-shell nanoparticles

NASA Astrophysics Data System (ADS)

Callini, E.; Pasquini, L.; Piscopiello, E.; Montone, A.; Antisari, M. Vittori; Bonetti, E.

2009-06-01

Mg nanoparticles with metal-oxide core-shell morphology were synthesized by inert-gas condensation and decorated by in situ Pd deposition. Transmission electron microscopy and x-ray diffraction underline the formation of a noncontinuous layer with Pd clusters on top of the MgO shell. Even in the presence of a thick MgO interlayer, a modest (2 at. %) Pd decoration deeply enhances the hydrogen sorption properties: previously inert nanoparticles exhibit metal-hydride transformation with fast kinetics and gravimetric capacity above 5 wt %.

Chondrogenic differentiation of ATDC5-cells under the influence of Mg and Mg alloy degradation.

PubMed

Martinez Sanchez, Adela H; Feyerabend, Frank; Laipple, Daniel; Willumeit-Römer, Regine; Weinberg, Annelie; Luthringer, Bérengère J C

2017-03-01

Biodegradable magnesium (Mg)-based materials are a potential alternative to permanent implants for application in children. Nevertheless effects of those materials on growth plate cartilage and chondrogenesis have not been previously evaluated. In vitro differentiation of ATDC5 cells was evaluated under the influence of pure Mg (PMg), Mg with 10wt% of gadolinium (Mg-10Gd) and Mg with 2wt% of silver (Mg-2Ag) degradation products (extracts) and direct cell culture on the materials. Gene expression showed an inhibitory effect on ATDC5 mineralization with the three extracts and a chondrogenic potential of Mg-10Gd. Cells cultured in Mg-10Gd and Mg-2Ag extracts showed the same proliferation and morphology than cells cultured in growth conditions. Mg-10Gd induced an increase in production of ECM and a bigger cell size, similar to the effects found with differentiation conditions. An increased metabolic activity was observed in cells cultured under the influence of Mg-10Gd extracts, indicated by an acidic pH during most of the culture period. After 7days of culture on the materials, ATDC5 growth, distribution and ECM synthesis were higher on Mg-10Gd samples, followed by Mg-2Ag and PMg, which was influenced by the homogeneity and composition of the degradation layer. This study confirmed the tolerance of ATDC5 cells to Mg-based materials and a chondrogenic effect of Mg-10Gd. Further studies in vitro and in vivo are necessary to evaluate cell reactions to those materials, as well as the effects on bone growth and the biocompatibility of the alloying system in the body. Copyright © 2016 Elsevier B.V. All rights reserved.

Modulation of Mg2+ influx and cytoplasmic free Mg2+ concentration in rat ventricular myocytes.

PubMed

Tashiro, Michiko; Inoue, Hana; Konishi, Masato

2018-06-16

To examine whether TRPM7, a member of the melastatin family of transient receptor potential channels, is a physiological pathway for Mg 2+ entry in mammalian cells, we studied the effect of TRPM7 regulators on cytoplasmic free Mg 2+ concentration ([Mg 2+ ] i ) of rat ventricular myocytes. Acutely isolated single cells were AM-loaded with the fluorescent indicator furaptra, and [Mg 2+ ] i was estimated at 25 °C. After [Mg 2+ ] i was lowered by soaking the cells with a high-K + and Mg 2+ -Ca 2+ -free solution, [Mg 2+ ] i was recovered by extracellular perfusion of Ca 2+ -free Tyrode's solution that contained 1 mM Mg 2+ . The initial rate of increase in [Mg 2+ ] i was analyzed as the Mg 2+ influx rate. The Mg 2+ influx rate was increased by the TRPM7 activator, naltriben (2-50 μM), in a concentration-dependent manner with a half maximal effective concentration (EC 50 ) of 24 μM. This EC 50 value is similar to that reported for the activation of recombinant TRPM7 overexpressed in HEK293 cells. Naltriben (50 μM) caused little change in basal [Mg 2+ ] i (~ 0.9 mM) in Ca 2+ -free Tyrode's solution, but significantly raised [Mg 2+ ] i to 1.31 ± 0.03 mM in 94 min after the removal of extracellular Na + . Re-introduction of extracellular Na + lowered [Mg 2+ ] i back to the basal level even in the presence of naltriben. Application of 10 μM NS8593, an inhibitor of TRPM7, significantly lowered [Mg 2+ ] i to 0.72 ± 0.03 mM in 50-60 min independent of extracellular Na + . The results suggest that Mg 2+ entry through TRPM7 significantly contributes to physiological Mg 2+ homeostasis in mammalian heart cells.

Hydrodechlorination of Tetrachloromethane over Palladium Catalysts Supported on Mixed MgF₂-MgO Carriers.

PubMed

Bonarowska, Magdalena; Wojciechowska, Maria; Zieliński, Maciej; Kiderys, Angelika; Zieliński, Michał; Winiarek, Piotr; Karpiński, Zbigniew

2016-11-25

Pd/MgO, Pd/MgF₂ and Pd/MgO-MgF₂ catalysts were investigated in the reaction of CCl₄ hydrodechlorination. All the catalysts deactivated in time on stream, but the degree of deactivation varied from catalyst to catalyst. The MgF₂-supported palladium with relatively large metal particles appeared the best catalyst, characterized by good activity and selectivity to C₂-C₅ hydrocarbons. Investigation of post-reaction catalyst samples allowed to find several details associated with the working state of hydrodechlorination catalysts. The role of support acidity was quite complex. On the one hand, a definite, although not very high Lewis acidity of MgF₂ is beneficial for shaping high activity of palladium catalysts. The MgO-MgF₂ support characterized by stronger Lewis acidity than MgF₂ contributes to very good catalytic activity for a relatively long reaction period (~5 h) but subsequent neutralization of stronger acid centers (by coking) eliminates them from the catalyst. On the other hand, the role of acidity evolution, which takes place when basic supports (like MgO) are chlorided during HdCl reactions, is difficult to assess because different events associated with distribution of chlorided support species, leading to partial or even full blocking of the surface of palladium, which plays the role of active component in HdCl reactions.

Ultrafast Synthesis and Related Phase Evolution of Mg2Si and Mg2Sn Compounds

NASA Astrophysics Data System (ADS)

Zhang, Qiang; Lu, Qiangbing; Yan, Yonggao; Su, Xianli; Tang, Xinfeng

2017-05-01

Both Mg2Si and Mg2Sn compounds were synthesized by an ultra-fast self-propagating high-temperature synthesis (SHS) method. The data regarding SHS were obtained via theoretical calculation combined with experiments, showing that the adiabatic temperature T ad and ignition temperature T ig of Mg2Si are a little higher than those of Mg2Sn. The mechanism of phase evolution and the concomitant microstructure evolution during the synthesis process of Mg2Si and Mg2Sn compounds were investigated by adopting SHS technique coupled with a sudden quenching treatment. Differential scanning calorimetry (DSC), field emission scanning electron microscopy (FESEM), and x-ray powder diffraction (XRD) results indicate that Mg2Si compound can be directly synthesized through the reaction of Mg and Si elements at around 850 K. Correspondingly, the formation of Mg2Sn needs to undergo melting of Sn and the subsequent feeble reaction between Mg and Sn elements before the large scale transformation at 730 K. As the groundwork, this research embodies great significance for future study on the ultrafast SHS process of the ternary Mg2Si1- x Sn x solid solutions.

Use and Effects of Malaria Control Measures in Pregnancy in Lagos, Nigeria

PubMed Central

Amoo, A. O. J.; Akintunde, Grace B.; Ojelekan, Oluwole D.; König, Wolfgang; König, Brigitte

2011-01-01

In Nigeria, malaria causes up to 11% of maternal mortality. Our main aim was to find out the most common mosquito control measures employed by the pregnant women in Lagos and their effects on malaria infection. The study was carried out over a period of 6 months during which trained interviewers administered questionnaires to 400 pregnant women. The prevalence of malaria was 8.4%. There was no significant association between the prevalence of malaria and age, level of education, or occupation of the participants. Pregnant women in the age range 26-30 had the mean parasite density (409.9±196.80). Insecticide spray (32.8%), mosquito coil (27.5%), and insecticide-treated nets (ITN) (15.5%) were the major mosquito control measures employed by the participants while the prevalence of infection among them were 2.3%, 6.2%, and 3.2%, respectively (P<0.05). Only 18.3% of the women had taken more than one dose of intermittent preventive treatment (IPT), while another 11.8% had taken a single dose. The infection rate among them was 4.1% and 6.4%, respectively. Malaria prevalence was highest among those who had not received any dose of IPT (10%). This study showed that the use of ITN and IPT among the pregnant women were still unacceptably low. It also showed that the use of insecticide spray which was the most common malaria control measure adopted by the participants was effective despite the fact that it is not a National Malaria Control Policy. We recommend that a sustained integrated mosquito management and public education should be strengthened in Nigeria. PMID:22355203

Preliminary study of the characteristics of a high Mg containing Al-Mg-Si alloy

NASA Astrophysics Data System (ADS)

Yan, F.; McKay, B. J.; Fan, Z.; Chen, M. F.

2012-01-01

An Al-20Mg-4Si high Mg containing alloy has been produced and its characteristics investigated. The as-cast alloy revealed primary Mg2Si particles evenly distributed throughout an α-Al matrix with a β-Al3Mg2 fully divorced eutectic phase observed in interdendritic regions. The Mg2Si particles displayed octahedral, truncated octahedral, and hopper morphologies. Additions of Sb, Ti and Zr had a refining influence reducing the size of the Mg2Si from 52 ± 4 μm to 25 ± 0.1 μm, 35 ± 1 μm and 34 ± 1 μm respectively. HPDC tensile test samples could be produced with a 0.6 wt.% Mn addition which prevented die soldering. Solution heating for 1 hr was found to dissolve the majority of the Al3Mg2 eutectic phase with no evidence of any effect on the primary Mg2Si. Preliminary results indicate that the heat treatment has a beneficial effect on the elongation and the UTS.

Formation and Corrosion Resistance of Mg-Al Hydrotalcite Film on Mg-Gd-Zn Alloy

NASA Astrophysics Data System (ADS)

Ba, Z. X.; Dong, Q. S.; Kong, S. X.; Zhang, X. B.; Xue, Y. J.; Chen, Y. J.

2017-06-01

An environment-friendly technique for depositing a Mg-Al hydrotalcite (HT) (Mg6Al2(OH)16-CO3ṡ4H2O) conversion film was developed to protect the Mg-Gd-Zn alloy from corrosion. The morphology and chemical compositions of the film were analyzed by scanning electronic microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy (RS), respectively. The electrochemical test and hydrogen evolution test were employed to evaluate the biocorrosion behavior of Mg-Gd-Zn alloy coated with the Mg-Al HT film in the simulated body fluid (SBF). It was found that the formation of Mg-Al HT film was a transition from amorphous precursor to a crystalline HT structure. The HT film can effectively improve the corrosion resistance of magnesium alloy. It indicates that the process provides a promising approach to modify Mg-Gd-Zn alloy.

The combination of amlodipine/valsartan 5/160 mg produces less peripheral oedema than amlodipine 10 mg in hypertensive patients not adequately controlled with amlodipine 5 mg

PubMed Central

Schrader, J; Salvetti, A; Calvo, C; Akpinar, E; Keeling, L; Weisskopf, M; Brunel, P

2009-01-01

Aims: To demonstrate the benefit of the combination amlodipine/valsartan 5/160 mg over amlodipine 10 mg, in producing a lower incidence of peripheral oedema for a comparable mean sitting systolic blood pressure (MSSBP) reduction. Methods: After a 4-week amlodipine 5 mg run-in phase, inadequately controlled hypertension patients (aged ≥ 55 years, MSSBP ≥ 130 and ≤ 160 mmHg) were randomised to receive amlodipine/valsartan 5/160 mg or amlodipine 10 mg for 8 weeks, followed by amlodipine/valsartan 5/160 mg for 4 weeks for all patients. Primary variables were MSSBP change from baseline to week 8 and incidence of peripheral oedema reported as an AE. Resolution of peripheral oedema was assessed 4 weeks after switching patients from amlodipine 10 mg to amlodipine/ valsartan 5/160 mg. Results: At week 8, MSSBP showed greater reduction with amlodipine/valsartan 5/160 mg than amlodipine 10 mg (least square mean: −8.01 vs.−5.95 mmHg, p<0.001 for non-inferiority and p=0.002 for superiority). Systolic control, overall BP control and systolic response rate at week 8 were significantly higher with combination than amlodipine 10 mg (34 vs. 26%; 57 vs. 50%; 36.57 vs. 27.77%, respectively). Incidence of peripheral oedema was significantly lower with the combination than amlodipine 10 mg (6.6 vs. 31.1%, p<0.001). Peripheral oedema resolved in 56% patients who switched from amlodipine 10 mg to the combination, without the loss of effect on BP reduction. Conclusion: In non-responders to amlodipine 5 mg, treatment with amlodipine/valsartan 5/160 mg induced significantly less peripheral oedema than amlodipine 10 mg for similar BP reduction. Peripheral oedema resolved in > 50% patients switching from amlodipine 10 mg to the combination. PMID:19196360

Ultra-high Strength Nanostructured Mg

DTIC Science & Technology

2014-03-31

27709-2211 Nanostructured Mg and Mg alloys, Mg metallic glass, Cryomilling, Powder consolidation, Spark plasma sintering , Deformation mechanisms REPORT...mechanically milled powder and high pressure on spark plasma sintering of Mg-Cu-Gd metallic glasses; (9) microstructure and mechanical behavior of Mg-10Li-3Al...pressure on spark plasma sintering of Mg– Cu–Gd metallic glasses, Acta Materialia , (07 2013): 4414. doi: Baolong Zheng, Ying Li, Weizong Xu

Melting relations in the MgO-MgSiO3 system up to 70 GPa

NASA Astrophysics Data System (ADS)

Ohnishi, Satoka; Kuwayama, Yasuhiro; Inoue, Toru

2017-06-01

Melting experiments in a binary system MgO-MgSiO3 were performed up to 70 GPa using a CO2 laser heated diamond anvil cell. The quenched samples were polished and analyzed by a dualbeam focused ion beam (FIB) and a field emission scanning electron microscope (FE-SEM), respectively. The liquidus phase and the eutectic composition were determined on the basis of textual and chemical analyses of sample cross sections. Our experimental results show that the eutectic composition is the Si/Mg molar ratio of 0.76 at 35 GPa and it decreases with increasing pressure. Above 45 GPa, it becomes relatively constant at about 0.64-0.65 Si/Mg molar ratio. Using our experimental data collected at a wide pressure range up to 70 GPa together with previous experimental data, we have constructed a thermodynamic model of the eutectic composition of the MgO-MgSiO3 system. The eutectic composition extrapolated to the pressure and temperature conditions at the base of the mantle is about 0.64 Si/Mg molar ratio. The modeled eutectic composition is quite consistent with a previous prediction from ab initio calculations (de Koker et al. in Earth Planet Sci Lett 361:58-63, 2013), suggesting that the simple assumption of a non-ideal regular solution model can well describe the melting relation of the MgO-MgSiO3 system at high pressure. Our results show that the liquidus phase changes from MgO-periclase to MgSiO3-bridgmanite at 35 GPa for the simplified pyrolite composition ( 0.7 Si/Mg molar ratio), while MgSiO3-bridgmanite is the liquidus phase at the entire lower mantle conditions for the chondritic composition ( 0.84 Si/Mg molar ratio).

Holocene paleoclimate inferred from salinity histories of adjacent lakes in southwestern Sicily (Italy)

USGS Publications Warehouse

Curry, B Brandon; Henne, Paul; Mezquita-Joanes, Francesc; Marrone, Federico; Pieri, Valentina; La Mantia, Tommaso; Calo, Camilla; Tinner, Willy

2016-01-01

Marked uncertainties persist regarding the climatic evolution of the Mediterranean region during the Holocene. For instance, whether moisture availability gradually decreased, remained relatively constant, or increased during the last 7000 years remains a matter of debate. To assess Holocene limnology, hydrology and moisture dynamics, the coastal lakes Lago Preola and Gorgo Basso, located in southwestern Sicily, were investigated through several stratigraphic analyses of ostracodes, including multivariate analyses of assemblages, transfer functions of salinity, and biochemical analyses of valves (Sr/Ca, δ18O and δ13C). During the early Holocene, the Gorgo Basso and Lago Preola ostracode records are similar. After an initial period of moderate salinity (1690–6100 mg/l from ca. 10,000–8190 cal yr BP), syndepositional or diagenetic dissolution of ostracode valves suggests that salinity declined to <250 mg/L from ca. 8190 to 7000 cal yr BP at both sites. After ca. 6250 cal yr BP, the ostracode records are strikingly different. Lago Preola became much more saline, with paleosalinity values that ranged from 2270 to about 24,420 mg/L. We suggest that Lago Preola's change from a freshwater to mesosaline lake at about 6250 cal yr BP was related to sea level rise and resulting intrusion of seawater-influenced groundwater. In contrast, Gorgo Basso remained a freshwater lake. The salinity of Gorgo Basso declined somewhat after 6250 cal yr BP, in comparison to the early Holocene, ranging from about 550 to 1680 mg/L. Cypria ophtalmica, a species capable of rapid swimming and flourishing in waters with low dissolved oxygen levels, became dominant at approximately the time when Greek civilization took root in Sicily (2600 cal yr BP), and it completely dominates the record during Roman occupation (roughly 2100 to 1700 cal yr BP). These freshwater conditions at Gorgo Basso suggest high effective moisture when evergreen olive-oak forests collapsed in response

Holocene paleoclimate inferred from salinity histories of adjacent lakes in southwestern Sicily (Italy)

NASA Astrophysics Data System (ADS)

Curry, Brandon; Henne, Paul D.; Mesquita-Joanes, Francesc; Marrone, Federico; Pieri, Valentina; La Mantia, Tommaso; Calò, Camilla; Tinner, Willy

2016-10-01

Marked uncertainties persist regarding the climatic evolution of the Mediterranean region during the Holocene. For instance, whether moisture availability gradually decreased, remained relatively constant, or increased during the last 7000 years remains a matter of debate. To assess Holocene limnology, hydrology and moisture dynamics, the coastal lakes Lago Preola and Gorgo Basso, located in southwestern Sicily, were investigated through several stratigraphic analyses of ostracodes, including multivariate analyses of assemblages, transfer functions of salinity, and biochemical analyses of valves (Sr/Ca, δ18O and δ13C). During the early Holocene, the Gorgo Basso and Lago Preola ostracode records are similar. After an initial period of moderate salinity (1690-6100 mg/l from ca. 10,000-8190 cal yr BP), syndepositional or diagenetic dissolution of ostracode valves suggests that salinity declined to <250 mg/L from ca. 8190 to 7000 cal yr BP at both sites. After ca. 6250 cal yr BP, the ostracode records are strikingly different. Lago Preola became much more saline, with paleosalinity values that ranged from 2270 to about 24,420 mg/L. We suggest that Lago Preola's change from a freshwater to mesosaline lake at about 6250 cal yr BP was related to sea level rise and resulting intrusion of seawater-influenced groundwater. In contrast, Gorgo Basso remained a freshwater lake. The salinity of Gorgo Basso declined somewhat after 6250 cal yr BP, in comparison to the early Holocene, ranging from about 550 to 1680 mg/L. Cypria ophtalmica, a species capable of rapid swimming and flourishing in waters with low dissolved oxygen levels, became dominant at approximately the time when Greek civilization took root in Sicily (2600 cal yr BP), and it completely dominates the record during Roman occupation (roughly 2100 to 1700 cal yr BP). These freshwater conditions at Gorgo Basso suggest high effective moisture when evergreen olive-oak forests collapsed in response to increased Greco

Enhancing phosphate adsorption by Mg/Al layered double hydroxide functionalized biochar with different Mg/Al ratios.

PubMed

Li, Ronghua; Wang, Jim J; Zhou, Baoyue; Awasthi, Mukesh Kumar; Ali, Amjad; Zhang, Zengqiang; Gaston, Lewis A; Lahori, Altaf Hussain; Mahar, Amanullah

2016-07-15

Mg/Al ratio plays a significant role for anion adsorption by Mg/Al-layered double hydroxides (Mg/Al-LDHs) modified biochar. In this study, Mg/Al-LDHs biochar with different Mg/Al ratios (2, 3, 4) were prepared by co-precipitation for phosphate removal from aqueous solution. Factors on phosphate adsorption including Mg/Al ratio, pH, and the presence of other inorganic anions were investigated through batch experiments. Increasing Mg/Al ratio in the Mg/Al-LDHs biochar composites generally enhanced phosphate adsorption with Langmuir adsorption maximum calculated at 81.83mg phosphorous (P) per gram of 4:1Mg/Al-LDHs biochar at pH3.0. The adsorption process was best described by the pseudo-second-order kinetic model. Solution pH had greater effects on the phosphate adsorption by Mg/Al LDHs biochar composites with lower Mg/Al ratios. The presence of other inorganic anions decreased the phosphate adsorption efficiency in the order of F(-) > SO4(2-) > NO2(-) >Cl(-). Phosphate adsorption mechanism involves ion exchange, electrostatic attraction and surface inner-sphere complex formation. Overall, Mg/Al-LDHs biochar composites offer a potential alternative of carbon-based adsorbent for phosphate removal from aqueous solution. Copyright © 2016 Elsevier B.V. All rights reserved.

Magnesium and cadmium containing Heusler phases REPd2Mg, REPd2Cd, REAg2Mg, REAu2Mg and REAu2Cd

NASA Astrophysics Data System (ADS)

Johnscher, Michael; Stein, Sebastian; Niehaus, Oliver; Benndorf, Christopher; Heletta, Lukas; Kersting, Marcel; Höting, Christoph; Eckert, Hellmut; Pöttgen, Rainer

2016-02-01

Twenty-eight new Heusler phases REPd2Mg, REPd2Cd, REAg2Mg, REAu2Mg and REAu2Cd with different rare earth elements were synthesized from the elements in sealed niobium ampoules in a water-cooled sample chamber of an induction furnace. The samples were characterized by powder X-ray diffraction. The cell volumes show the expected lanthanide contraction. The structures of YPd2Cd, GdPd2Cd, GdAu2Cd, Y1.12Ag2Mg0.88 and GdAg2Mg were refined based on single crystal diffractometer data. The magnetic properties were determined for fifteen phase pure samples. LuAu2Mg is a weak Pauli paramagnet with a susceptibility of 1.0(2) × 10-5 emu mol-1 at room temperature. The remaining samples show stable trivalent rare earth ions and most of them order magnetically at low temperatures. The ferromagnet GdAg2Mg shows the highest ordering temperature of TC = 98.3 K. 113Cd and 89Y MAS NMR spectra of YAu2Cd and YPd2Cd confirm the presence of unique crystallographic sites. The resonances are characterized by large Knight shifts, whose magnitude can be correlated with electronegativity trends.

[Sinusal penetration of amoxicillin-clavulanic acid. Formulation 1 g./125 mg., twice daily versus formulation 500 mg./125 mg., three times daily].

PubMed

Jehl, F; Klossek, J M; Peynegre, R; Serrano, E; Castillo, L; Bobin, S; Desprez, D; Renault, C; Neel, V; Rouffiac, E; Borie, C

2002-10-19

In order to meet the evolution of pneumococcus resistance to beta-lactam antibiotics, a new formulation of amoxicillin (AMX) and clavulanic acid (CA), with twice as much AMX (1 g/125 mg vs. 500 mg/125 mg) was developed for the treatment of acute pneumonia in patients at risk. This formulation can also be used in the treatment of acute maxillary sinusitis using a 1 g/125 mg regimen twice-daily. Compare the sinusal penetration of AMX and CA (1 g/125 mg twice-daily vs. 500 mg/125 mg three times a day) when administered at both regimens to demonstrate equivalent pharmacokinetic and pharmacodynamic behaviour of the former when compared to the latter. Concentrations of AMX and CA were measured in the anterior ethmoid, maxillary, posterior ethmoid sinus and in the middle nasa concha in 62 patients undergoing surgery for nasosinusal polyps. Patients randomised in two groups corresponding to 2 oral regimens, received either 1 g/125 mg twice a day or 500 mg/125 mg three times a day for 4 days. The last dose in both groups was administered 1 h 30, 3, 5 or 8 hrs prior to surgery. Serum samples were taken simultaneously to tissue samples. AMX and CA were measured by high performance liquid chromatography. Exogenous and above all endogenous blood contamination were taken into account with the hematocrit as well as blood and tissue haemoglobin concentrations. Comparisons of tissue concentrations were made for each sampling time, according to values obtained for a specific tissue with both doses on one hand, and on the other to values obtained with a specific dose in different tissues. The calculated pharmacodynamic parameters, which are considered to be predictive for bacteriological and clinical efficacy, result directly from tissue concentrations of AMX. tissue inhibitory quotients (IQtissue = Tissue concentration/MIC). time above MICs for serum and tissue concentrations (T > MIC). As regards AMX, whatever the dose, at 1 h 30 and at 3 hrs, tissue concentrations did not differ

Mg-Ca Alloys Produced by Reduction of CaO: Understanding of ECO-Mg Alloy Production

NASA Astrophysics Data System (ADS)

Jung, In-Ho; Lee, Jin Kyu; Kim, Shae K.

2017-04-01

There have been long debates about the environment conscious (ECO) Mg technology which utilizes CaO to produce Ca-containing Mg alloys. Two key process technologies of the ECO-Mg process are the chemical reduction of CaO by liquid Mg and the maintenance of melt cleanliness during the alloying of Ca. Thermodynamic calculations using FactSage software were performed to explain these two key issues. In addition, an experimental study was performed to compare the melt cleanliness of the Ca-containing Mg alloys produced by the conventional route with metallic Ca and the ECO-Mg route with CaO.

Determination of the total level of nitrosamines in select consumer products in Lagos area of Nigeria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coker, H.A.B.; Thomas, A.E.; Akintonwa, A.

1991-11-01

For some time there has been a considerable interest and growing concern in the extent of contamination of food items by N-nitrosamines because of the known carcinogenicity and mutagenicity of these compounds. Nitrosamines can be derived from the interaction of organic secondary and tertiary amines with nitrite, nitrate under reducing conditions, low pH values or nitrous gases. In Nigeria, the present harsh economic conditions have somewhat influenced the emergence of different kinds of socioeconomic attitude in Nigerians. There is now high incidence of adulteration of many consumer products. Faking of assorted consumables and pharmaceuticals, notably drugs, is a common feature,more » all in attempt to cut corners. It is a common practice amongst the local people to use certain chemicals as preservatives, colorants and flavorants without taking cognizance of the long-term health and toxicological hazards posed to the citizenry by these foreign agents. Recent work in the authors' laboratory had shown the presence of N-nitrosamines in some consumer products and it was therefore thought that a more thorough investigation and survey of as many foods and drinks as possible in the Lagos metropolis for contamination by nitrosamines might present a more revealing picture.« less

A survey of operational characteristics, socioeconomic and health effects of scavenging activity in Lagos, Nigeria.

PubMed

Afon, Abel

2012-07-01

This study presents the social, economic, health and environmental implications of solid waste scavenging activity in Olusosun, one of the government's designated open waste dumpsites in Lagos, Nigeria. Using incidental or convenience sampling methods of questionnaire administration, 112 scavengers were sampled. It was established that scavenging on the site was only possible through registration with an associate on site. Recovering items from hills of waste involved physical energy and the use of manually-operated rudimentary equipment. Thus, 87% of the scavengers were males in their early twenties (minimum age = 19 years; maximum age = 35 years; mean = 26.7 years; SD = 4.2). The daily mean income from the exercise was Naira 480.80 (Naira 160 = $1.00). The most important method of arriving at the selling prices of the scavenged products was the use of scale measurement. Although the scavengers were aware that scavenging exposed them to both environmental and health hazards, they continued scavenging for economic and social reasons. The study concluded that because of the level of employment provided and the large number of people directly involved (1243 on this site alone), outright banning, even when the open dump is closed down, without rehabilitating the scavengers will constitute a social, economic and security threat to the community. Scavenging should, therefore, be integrated fully into the waste-management system and regulated.

Solid waste generation and characterization in the University of Lagos for a sustainable waste management.

PubMed

Adeniran, A E; Nubi, A T; Adelopo, A O

2017-09-01

Waste characterization is the first step to any successful waste management policy. In this paper, the characterization and the trend of solid waste generated in University of Lagos, Nigeria was carried out using ASTM D5231-92 and Resource Conservation Reservation Authority RCRA Waste Sampling Draft Technical Guidance methods. The recyclable potential of the waste is very high constituting about 75% of the total waste generated. The estimated average daily solid waste generation in Unilag Akoka campus was estimated to be 32.2tons. The solid waste characterization was found to be: polythene bags 24% (7.73tons/day), paper 15% (4.83tons/day), organic matters 15%, (4.83tons/day), plastic 9% (2.90tons/day), inert materials 8% (2.58tons/day), sanitary 7% (2.25tons/day), textile 7% (2.25tons/day), others 6% (1.93tons/day), leather 4% (1.29tons/day) metals 3% (0.97tons/day), glass 2% (0.64tons/day) and e-waste 0% (0.0tons/day). The volume and distribution of polythene bags generated on campus had a positive significant statistical correlation with the distribution of commercial and academic structures on campus. Waste management options to optimize reuse, recycling and reduce waste generation were discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis of Mg(OH) 2, MgO, and Mg nanoparticles using laser ablation of magnesium in water and solvents

NASA Astrophysics Data System (ADS)

Phuoc, Tran X.; Howard, Bret. H.; Martello, Donald V.; Soong, Yee; Chyu, Minking K.

2008-11-01

Laser ablation of magnesium in deionized water (DW), solutions of DW and sodium dodecyl sulfate (SDS) with different concentrations, acetone and 2-propanol has been conducted. The results showed that ablation in acetone and 2-propanol yielded MgO and Mg nanocrystallites as isolated particles and agglomerated chains probably intermixed with organic residues resulting from the alteration/decomposition of the solvents under the high-energy conditions. Brucite-like Mg(OH) 2 particles were mainly produced by laser ablation of Mg in either DW or DW-SDS solutions. Ablation in DW yielded particles of fiber-like shapes having a diameter of about 5-10 nm and length as long as 150 nm. Materials produced in DW-SDS solutions were composed of various size and shape particles. Some had rough surfaces with irregular shapes. Small particles were about 20-30 nm and larger particles were about 120 nm. Particles with rod-like, triangular, and plate-like shapes were also observed.

The MG Composite

PubMed Central

Burns, Ted M.; Conaway, Mark; Sanders, Donald B.

2010-01-01

Objective: To study the concurrent and construct validity and test-retest reliability in the practice setting of an outcome measure for myasthenia gravis (MG). Methods: Eleven centers participated in the validation study of the Myasthenia Gravis Composite (MGC) scale. Patients with MG were evaluated at 2 consecutive visits. Concurrent and construct validities of the MGC were assessed by evaluating MGC scores in the context of other MG-specific outcome measures. We used numerous potential indicators of clinical improvement to assess the sensitivity and specificity of the MGC for detecting clinical improvement. Test-retest reliability was performed on patients at the University of Virginia. Results: A total of 175 patients with MG were enrolled at 11 sites from July 1, 2008, to January 31, 2009. A total of 151 patients were seen in follow-up. Total MGC scores showed excellent concurrent validity with other MG-specific scales. Analyses of sensitivities and specificities of the MGC revealed that a 3-point improvement in total MGC score was optimal for signifying clinical improvement. A 3-point improvement in the MGC also appears to represent a meaningful improvement to most patients, as indicated by improved 15-item myasthenia gravis quality of life scale (MG-QOL15) scores. The psychometric properties were no better for an individualized subscore made up of the 2 functional domains that the patient identified as most important to treat. The test-retest reliability coefficient of the MGC was 98%, with a lower 95% confidence interval of 97%, indicating excellent test-retest reliability. Conclusions: The Myasthenia Gravis Composite is a reliable and valid instrument for measuring clinical status of patients with myasthenia gravis in the practice setting and in clinical trials. PMID:20439845

Environmental and climatic conditions at a potential Glacial refugial site of tree species near the Southern Alpine glaciers. New insights from multiproxy sedimentary studies at Lago della Costa (Euganean Hills, Northeastern Italy)

NASA Astrophysics Data System (ADS)

Kaltenrieder, Petra; Belis, Claudio A.; Hofstetter, Simone; Ammann, Brigitta; Ravazzi, Cesare; Tinner, Willy

2009-12-01

It has been hypothesized that refugia of thermophilous tree species were located in Northern Italy very close to the Alps, though, this hypothesis has yet to be tested thoroughly. In contrast to Central and Southern Italy with its relative wealth of data, only a few fragmentary records are currently available from Northern Italy for the last Glacial (Würm, Weichselian). Our new study site Lago della Costa lies adjacent to the catchment of the megafans of the Alpine forelands and the braided rivers of the Northeastern Po Plain that have so far inhibited the recovery of continuous Glacial and Late-Glacial records. We analyze pollen, plant macrofossils, charcoal and ostracods to reconstruct the vegetation, fire and lake history for the period 33,000-16,000 cal. BP. We compare our data with Glacial records from Southern Europe to discuss similarities and dissimilarities between these potential refugial areas. A comparison with independent paleoclimatic proxies allows to assess potential linkages between environmental and climatic variability. New macrofossil and pollen data at Lago della Costa unambiguously document the local persistence of boreal tree taxa such as Larix decidua and Betula tree species around the study site during the last Glacial. The regular occurrence of pollen of temperate trees in the organic lake sediments (fine-detritus calcareous gyttja) suggests that temperate taxa such as Corylus avellana, Quercus deciduous, Tilia, Ulmus, Fraxinus excelsior, Carpinus, Abies alba and Fagus sylvatica, most likely survived the Last Glacial Maximum (LGM) at favorable sites in the Euganean Hills. The percentage values of temperate trees are comparable with those from Southern Europe (e.g. Monticchio in Southern Italy). We conclude that the Euganean Hills were one of the northernmost refugial areas of temperate taxa in Europe. However, the relative and absolute abundances of pollen of temperate trees are highly variable. Pollen-inferred declines of temperate tree

Diffusion coefficients of Mg isotopes in MgSiO3 and Mg2SiO4 melts calculated by first-principles molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Liu, Xiaohui; Qi, Yuhan; Zheng, Daye; Zhou, Chen; He, Lixin; Huang, Fang

2018-02-01

The mass dependence of diffusion coefficient (D) can be described in the form of Di/Dj = (mj/mi)β, where m denotes masses of isotope i and j, and β is an empirical parameter as used to quantify the diffusive transport of isotopes. Recent advances in computation techniques allow theoretically calculation of β values. Here, we apply first-principles Born-Oppenheimer molecular dynamics (MD) and pseudo-isotope method (taking mj/mi = 1/24, 6/24, 48/24, 120/24) to estimate β for MgSiO3 and Mg2SiO4 melts. Our calculation shows that β values for Mg calculated with 24Mg and different pseudo Mg isotopes are identical, indicating the reliability of the pseudo-isotope method. For MgSiO3 melt, β is 0.272 ± 0.005 at 4000 K and 0 GPa, higher than the value calculated using classical MD simulations (0.135). For Mg2SiO4 melt, β is 0.184 ± 0.006 at 2300 K, 0.245 ± 0.007 at 3000 K, and 0.257 ± 0.012 at 4000 K. Notably, β values of MgSiO3 and Mg2SiO4 melts are significantly higher than the value in basalt-rhyolite melts determined by chemical diffusion experiments (0.05). Our results suggest that β values are not sensitive to the temperature if it is well above the liquidus, but can be significantly smaller when the temperature is close to the liquidus. The small difference of β between silicate liquids with simple compositions of MgSiO3 and Mg2SiO4 suggests that the β value may depend on the chemical composition of the melts. This study shows that first-principles MD provide a promising tool to estimate β of silicate melts.

Trace elements and oxidative stress levels in the blood of painters in Lagos, Nigeria: occupational survey and health concern.

PubMed

Awodele, Olufunsho; Akinyede, Akin; Babawale, Omotola Opeyemi; Coker, Herbert A Babatunde; Akintonwa, Alade

2013-06-01

Adverse effects attributed to exposure to paints are currently a concern because of the continued widespread use of paint containing trace elements. Thus, occupational survey amongst painters in Lagos and determination of trace elements and oxidative stress parameters were carried out. Descriptive cross-sectional survey was done using a standardized questionnaire to obtain job safety-related information. Forty-eight percent of the painters were aware of hazards associated with painting and 52 % of these workers were aware of the necessary precautionary measures during painting. There were no significant differences (p ≥ 0.05) between the levels of trace elements in the blood of painters and the control subjects. However, there was a significance increase (p ≤ 0.0001) in the level of malondialdehyde and a decrease (p ≤ 0.001) in the levels of reduced glutathione, superoxide dismutase, and catalase of the painters compared to the control. An increase in oxidative stress parameters may not only be due to trace element concentrations, but also the painters' exposure to some petrochemical solvents during mixing of paints.

Life-stages, exploitation status and habitat use of Lutjanus goreensis (Perciformes: Lutjanidae) in coastal marine environments of Lagos, SW Nigeria.

PubMed

Kafayat, A Fakoya; Martins, A Anetekhai; Shehu, L Akintola; Abdulwakil, O Sabal; Abass, Mikhail A

2015-03-01

The Gorean snapper, Lutanus goreensis is an important component of artisanal fisheries and trawl landings in the Gulf of Guinea. Despite its economic importance, there is a dearth of information on size structure and life history strategies of the species. Therefore, the objectives of this study were to provide baseline data on the life stages, exploitation status and habitat use for the species in Nigeria. Monthly samples were obtained from artisanal and trawl catches in Five Cowrie Creek and Lagos coastal waters between December 2008 and December 2010, respectively. Length-frequency distributions of the fishes caught were analysed to provide preliminary information on mean and modal lengths at capture and life-history strategies based on habitat use and estuarine-dependency for L. goreensis. A total of 822 specimens of L. goreensis were collected from Five Cowrie Creek while 377 specimens were collected from Lagos coastal waters. Total length varied between 7.90-34.90 cm for creek samples and from 21.90-56.10 cm for marine samples. Length-frequency histograms showed polymodal size distributions in creek and marine samples. Length-frequency distributions of L. goreensis showed a high abundance ofjuveniles (<20 cm) and sub-adults (20-35 cm) which accounted for 84.1% and 68.4% of creek and marine samples examined, respectively. For the creek samples, fish in modal length class of 13.00-13.99 cm were the most exploited while in the marine samples, length classes of 29.00-30.99 cm and 31.00-32.99cm constituted the most frequently exploited fishes. Increase in total lengths from the creek (mean +/- SD; 16.19 +/- 3.73 cm) to the marine habitat samples (32.89 +/- 6.14 cm) indicated ontogenetic shift in habitat use. Occurrence of a predominant juvenile population in Five Cowrie Creek by L. goreensis suggests estuarine-dependency and is indicative of a temporary juvenile habitat or a migratory corridor. In conclusion, data from the presently reported study and previous

Constraints on the ^22Ne(α,n)^25Mg reaction rate from ^natMg+n Total and ^25Mg(n,γ ) Cross Sections

NASA Astrophysics Data System (ADS)

Koehler, Paul

2002-10-01

The ^22Ne(α,n)^25Mg reaction is the neutron source during the s process in massive and intermediate mass stars as well as a secondary neutron source during the s process in low mass stars. Therefore, an accurate determination of this rate is important for a better understanding of the origin of nuclides heavier than iron as well as for improving s-process models. Also, because the s process produces seed nuclides for a later p process in massive stars, an accurate value for this rate is important for a better understanding of the p process. Because the lowest observed resonance in direct ^22Ne(α,n)^25Mg measurements is considerably above the most important energy range for s-process temperatures, the uncertainty in this rate is dominated by the poorly known properties of states in ^26Mg between this resonance and threshold. Neutron measurements can observe these states with much better sensitivity and determine their parameters much more accurately than direct ^22Ne(α,n)^25Mg measurements. I have analyzed previously reported Mg+n total and ^25Mg(n,γ ) cross sections to obtain a much improved set of resonance parameters for states in ^26Mg in this region, and an improved estimate of the uncertainty in the ^22Ne(α,n)^25Mg reaction rate. This work was supported by the U.S. DOE under contract No. DE-AC05-00OR22725 with UT-Battell, LLC.

Measuring one nucleon transfer reaction 24Mg( p, d)23Mg for astrophysical reaction rates

NASA Astrophysics Data System (ADS)

Lee, E. J.; Chae, K. Y.

2017-12-01

The level structure of a radionuclide 23Mg has been studied by using the 24Mg( p, d)23Mg one nucleon transfer reaction measurement for the astrophysical 19Ne(α, γ)23Mg reaction rate. A 41 MeV proton beam was produced and accelerated at the 25 MV tandem accelerator of the Holifield Radioactive Ion Beam Facility of the Oak Ridge National Laboratory in the United States. The beam particles impinged on an isotopically-enriched 24Mg solid target. Angular distributions of recoiling deuterons were extracted by using a large area silicon strip detector array. By comparing the experimentally-obtained angular distributions with zero range distorted wave Born approximation calculations, spins and parities of three energy levels of 23Mg could be constrained for the first time, which is very important information needed to understand the 19Ne(α, γ)23Mg reaction rate.

The Recrystallization Behavior of Unalloyed Mg and a Mg-Al Alloy

NASA Astrophysics Data System (ADS)

Murphy, Aeriel D.; Allison, John E.

2018-02-01

The static recrystallization behavior of pure Mg and Mg-4Al was characterized over a range of annealing temperatures. The electron backscatter diffraction grain orientation spread technique was used to quantify the level of recrystallization at various annealing times. Recrystallization kinetics were characterized using the Johnson-Mehl-Avrami-Kolmogorov (JMAK) relationship and it was found that two sequential annealing stages exist. Stage 1 involves heterogeneous nucleation of recrystallization in regions with a high stored energy, including twins and grain boundaries, and can be represented by an Avrami exponent of n 1 ranging from 0.35 to 0.6. During Stage 2, recrystallization occurred predominately in the interior of deformed grains with incomplete recrystallization generally observed even at annealing times in excess of two weeks. The second recrystallization stage exhibited a much lower Avrami exponent, n 2, ranging from 0.02 to 0.2. Increasing the starting grain size in the pure Mg condition led to a significant delay in recrystallization. The addition of Al had a minimal effect on the recrystallization kinetics of Mg.

Tobacco related knowledge and support for smoke-free policies among community pharmacists in Lagos state, Nigeria

PubMed Central

Poluyi, Edward O.; Odukoya, Oluwakemi O.; Aina, Bolajoko; Faseru, Babalola

2014-01-01

Background: There are no safe levels of exposure to second hand smoke and smoke-free policies are effective in reducing the burden of tobacco-related diseases and death. Pharmacists, as a unique group of health professionals, might be able to play a role in the promotion of smoke-free policies. Objective: To determine the tobacco-related knowledge of community pharmacists and assess their support for smoke-free policies in Lagos state, Nigeria. Methods: A cross-sectional descriptive study design using both quantitative and qualitative methods was employed. Two hundred and twelve randomly selected community pharmacists were surveyed using a pre-tested self-administered questionnaire. In addition, one focus group discussion was conducted with ten members of the Lagos state branch of the Association of Community Pharmacists of Nigeria. Results: The quantitative survey revealed that the majority (72.1%) of the respondents were aged between 20 and 40 years, predominantly male (60.8%), Yoruba (50.2%) or Igbo (40.3%) ethnicity and had been practicing pharmacy for ten years or less (72.2%). A majority (90.1%) of respondents were aware that tobacco is harmful to health. Slightly less (75.8%) were aware that second hand smoke is harmful to health. Among the listed diseases, pharmacists responded that lung (84.4%) and esophageal (68.9%) cancers were the most common diseases associated with tobacco use. Less than half of those surveyed associated tobacco use with heart disease (46.9%), chronic obstructive pulmonary disease (27.8%), bladder cancer (47.2%), peripheral vascular disease (35.8%) and sudden death (31.1%). Only 51.9% had heard of the World Health Organization Framework Convention on Tobacco Control (WHO FCTC). A little over half of the respondents (53.8%) were aware of any law in Nigeria controlling tobacco use. The majority of respondents supported a ban on smoking in homes (83.5%), in public places (79.2%), and in restaurants, nightclubs and bars (73.6%). For every

Esomeprazole 40 mg provides improved intragastric acid control as compared with lansoprazole 30 mg and rabeprazole 20 mg in healthy volunteers.

PubMed

Wilder-Smith, Clive H; Röhss, Kerstin; Nilsson-Pieschl, Catharina; Junghard, Ola; Nyman, Lars

2003-01-01

To compare the effects of standard-dose esomeprazole with those of standard doses of lansoprazole and rabeprazole on intragastric pH during repeated daily oral dosing in healthy volunteers. In two standardized, randomized crossover studies, Helicobacter pylori negative healthy volunteers (study A: 19 males, 5 females; study B: 13 males, 10 females) received esomeprazole 40 mg and either lansoprazole 30 mg (study A) or rabeprazole 20 mg (study B) orally once daily in the morning for 5 days. Continuous 24-hour intragastric pH recording was performed on day 5. The intragastric pH was maintained >4 for 65% (95% CI 59.5-71.3) of the 24-hour period with esomeprazole and for 53% of the time (95% CI 47.0-58.9) with lansoprazole in study A (p < 0.001). In study B, the proportion of time with pH >4 was 61% (95% CI 53.6-68.3) with esomeprazole versus 45% (95% CI 37.7-52.5) with rabeprazole (p = 0.005). The 24-hour median pH and the proportion of volunteers with intragastric pH >4 for > or =12 h and > or =16 h were significantly higher with esomeprazole than with either lansoprazole or rabeprazole. Esomeprazole 40 mg provides significantly more effective and more sustained gastric acid control than lansoprazole 30 mg or rabeprazole 20 mg in healthy volunteers. Copyright 2003 S. Karger AG, Basel

Three diverse target preparations: 14C (12 mg/cm 2), 71Ga 24Mg (12 mg/cm 271Ga, 3 mg/cm 224Mg), and 66,67Zn (1.8-14.9 mg/cm 2)

NASA Astrophysics Data System (ADS)

Lozowski, W. R.

1989-10-01

A natural-carbon analog of fluffy, intractable 14C powder was produced. With it, a method was developed to produce a pressed disk of 14C of 12.7-mg/cm 2 thickness and 1.27-cm diameter, bound with 2.1 wt.% of adhesive. Aluminized Mylar cover foils and a fritted-disc filter were used to contain the target for ( overlinep, p') experiments. Reduction of 71Ga 2O 3 to the metal was accomplished with an efficiency of 94.3% in a small electroplating cell. Magnesium was chosen as the companion element because 50 at.% could be tolerated in the (p, n) experiment, and GaMg has a melting point of 646 K. A 1.27-cm diameter target, supported at the edge by a Mg foil, was produced in several simple steps. Directly rollable 66,67Zn foils were obtained from an electroplating cell with a Pt screen anode and a highly polished tungsten-carbide cathode. Plating times of 3 h provided metal-recovery efficiencies ranging from 94.2 to 96.5%. The as-deposited foils had many holes but were hole-free and shiny after reduction of 25% by pack rolling.

Magnesium isotope fractionation between brucite [Mg(OH)2] and Mg aqueous species: Implications for silicate weathering and biogeochemical processes

NASA Astrophysics Data System (ADS)

Li, Weiqiang; Beard, Brian L.; Li, Chengxiang; Johnson, Clark M.

2014-05-01

Brucite, with its octahedral structure, has a lattice configuration that is similar to the Mg-bearing octahedral layers in phyllosilicates. Understanding stable Mg isotope fractionation between brucite and aqueous solution therefore bears on interpretation of Mg isotope data in natural weathering systems. In this study, we experimentally determined Mg isotope fractionation between brucite and two Mg aqueous species, the free Mg aquo ion ([Mg(OH2)6]2+) and EDTA-bonded Mg (Mg-EDTA2-). Results from recrystallization and brucite synthesis experiments suggest mild preferential partitioning of light Mg isotopes into brucite compared to Mg aquo ions at low temperatures, where measured ΔMgbrucite-Mg26 fractionation increased from ca. -0.3‰ at 7 °C, to ca. -0.2‰ at 22 °C, to ca. 0‰ at 40 °C. MgO hydrolysis experiments in EDTA-bearing solutions suggest that the ΔMgbrucite-Mg-EDTA26 fractionation is ⩾+2.0‰ at 22 °C, indicating that light Mg isotopes strongly partition into Mg-EDTA complex relative to brucite, as well as relative to Mg aquo ions. Magnesium atoms in brucite, Mg aquo ions, and Mg-EDTA complexes are all octahedrally coordinated, and the measured Mg isotope fractionations correlate with average bond lengths for Mg. Aqueous Mg ions have the shortest bond length among the three phases, and enrich heavy Mg isotopes relative to brucite and Mg-EDTA. In contrast, Mg-EDTA has the longest average bond length for Mg, and enriches light Mg isotopes relative to Mg aquo ions and brucite; the relatively long Mg-EDTA bond suggests that organically bound Mg may commonly have low 26Mg/24Mg ratios, which may explain proposed "vital" effects for stable Mg isotopes. Such relations between bond length and Mg isotope fractionation could be extended to other phyllosilicates such as serpentine- and clay-group minerals where Mg is also octahedrally coordinated.

Environmental evaluation of fluoride in drinking water at "Los Altos de Jalisco," in the central Mexico region.

PubMed

Hurtado, Roberto; Gardea-Torresdey, Jorge

Naturally occurring fluoride has been detected and quantified in drinking water in several cities of the "Los Altos de Jalisco" (LAJ) region. LAJ is located in the northeastern part of the state of Jalisco-Mexico, covering an area of 16,410 km2 with a population of 696,318 in 20 municipalities. Drinking water comes mainly from groundwater aquifers, located in the Trans-Mexican Volcanic Belt, which is a volcanic region characterized by hydrothermal activity. Results indicated that water supply from 42% of the municipalities had a fluoride concentration over the Mexican standards of 1.5 mg/L. It is important to notice that there are three cities, Lagos de Moreno (1.66-5.88 mg/L F(-)), Teocaltiche (3.82-18.58 mg/L F(-)), and Encarnación de Díaz (2.58-4.40 mg/L F(-)) where all water samples resulted in fluoride concentration over the maximum contaminant level. The total population from these three cities is over 122,000 inhabitants. Another important city with high levels of fluoride in the water supply was Tepatitlán de Morelos (2 wells with 6.54 and 13.47 mg/L F(-)). In addition to water supply, 30 samples of brand-name bottled water were tested. Surprisingly, 8 samples (27%) demonstrated fluoride level over the standards, mainly Agua de Lagos with 5.27 mg/L. Fluoridated table salt (200-300 mg/kg F(-)) is another important source of fluoride. A large number of people living in the region, mainly school children, might be under adverse health risk because they are consuming contaminated drinking water. It is well known that long-term exposure to water with high levels of fluoride produces severe health problems.

Atomic simulations of deformation mechanisms of crystalline Mg/amorphous Mg-Al nanocomposites

NASA Astrophysics Data System (ADS)

Song, H. Y.; Li, Y. L.

2015-09-01

The effects of amorphous boundary (AB) spacing on the deformation behavior of crystalline/amorphous (C/A) Mg/Mgsbnd Al nanocomposites under tensile load are investigated using molecular dynamics method. The results show that the plasticity of nano-polycrystal Mg can be enhanced with the introduction of C/A interfaces. For samples 5.2 nm in AB spacing and larger, the superior tensile ductility and nearly perfect plastic flow behavior occur during plastic deformation. The studies indicate that the cooperative interactions between crystalline and amorphous are the main reason for excellent ductility enhancements in C/A Mg/Mgsbnd Al nanocomposites.

Mg concentration profile and its control in the low temperature grown Mg-doped GaN epilayer

NASA Astrophysics Data System (ADS)

Liu, S. T.; Yang, J.; Zhao, D. G.; Jiang, D. S.; Liang, F.; Chen, P.; Zhu, J. J.; Liu, Z. S.; Liu, W.; Xing, Y.; Zhang, L. Q.; Wang, W. J.; Li, M.; Zhang, Y. T.; Du, G. T.

2018-01-01

In this work, the Cp2Mg flux and growth pressure influence to Mg doping concentration and depth profiles is studied. From the SIMS measurement we found that a transition layer exists at the bottom region of the layer in which the Mg doping concentration changes gradually. The thickness of transition layer decreases with the increases of Mg doping concentration. Through analysis, we found that this is caused by Ga memory effect which the Ga atoms stay residual in MOCVD system will react with Mg source, leading a transition layer formation and improve the growth rate. And the Ga memory effect can be well suppressed by increasing Mg doping concentration and growth pressure and thus get a steep Mg doping at the bottom region of p type layer.

Quasicrystal-reinforced Mg alloys

PubMed Central

Kyun Kim, Young; Tae Kim, Won; Hyang Kim, Do

2014-01-01

The formation of the icosahedral phase (I-phase) as a secondary solidification phase in Mg–Zn–Y and Mg–Zn–Al base systems provides useful advantages in designing high performance wrought magnesium alloys. The strengthening in two-phase composites (I-phase + α-Mg) can be explained by dispersion hardening due to the presence of I-phase particles and by the strong bonding property at the I-phase/matrix interface. The presence of an additional secondary solidification phase can further enhance formability and mechanical properties. In Mg–Zn–Y alloys, the co-presence of I and Ca2Mg6Zn3 phases by addition of Ca can significantly enhance formability, while in Mg–Zn–Al alloys, the co-presence of the I-phase and Mg2Sn phase leads to the enhancement of mechanical properties. Dynamic and static recrystallization are significantly accelerated by addition of Ca in Mg–Zn–Y alloy, resulting in much smaller grain size and more random texture. The high strength of Mg–Zn–Al–Sn alloys is attributed to the presence of finely distributed Mg2Sn and I-phase particles embedded in the α-Mg matrix. PMID:27877660

A fundamental study on the [(μ-Cl) 3 Mg 2 (THF) 6 ] + dimer electrolytes for rechargeable Mg batteries

DOE PAGES

Liu, Tianbiao; Cox, Jonathan T.; Hu, Dehong; ...

2015-01-05

We present a fundamental study on [(μ-Cl) 3 Mg 2 (THF) 6 ] + dimer electrolytes using various physical methods including Subambient Pressure Ionization with Nanoelectrospray Mass spectrometry (SPIN-MS), Raman spectroscopy, 25Mg{ 1H} NMR, 27Al{ 1H} NMR and electrochemical analysis. For the first time, long time sought THF solvated [MgCl] + species was experimentally characterized by SPIN mass spectrometry in the solution of the Mgdimer containing electrolyte, confirming the mono-Cl- abstraction reaction between MgCl 2 and an Al Lewis acid. Solvated MgCl 2 in the electrolyte was confirmed by Raman spectroscopy. The experimental results establish the previously proposed dimerization equilibriummore » of solvated [MgCl] + and MgCl2 with [(μ-Cl) 3Mg 2(THF)6] +. 25Mg{ 1H} NMR, 27Al{ 1H} NMR and electrochemical analysis on chloration reaction of [(μ-Cl) 3Mg 2(THF) 6]AlPh 3Cl with external Cl- led to further insights on the coordination chemistry of the dimer electrolyte. Finally, a comprehensive mechanism is proposed for the reversible electrochemical Mg deposition and stripping and Mg 2+ and Cl- ion transports of the Mg dimer electrolytes in rechargeable Mg batteries.« less

Growth dynamics controllable deposition of homoepitaxial MgO films on the IBAD-MgO substrates

NASA Astrophysics Data System (ADS)

Wang, Wei; Liu, Lin-Fei; Yao, Yan-Jie; Lu, Sai-Dan; Wu, Xiang; Zheng, Tong; Liu, Shun-Fan; Li, Yi-Jie

2018-03-01

Homoepitaxial MgO (Homo-MgO) films, deposited by RF magnetic sputtering method in various experimental conditions, were systematically studied using growth dynamics in older to fully understand their growth mechanism. The results showed that high quality Homo-MgO films could be obtained at high oxygen partial pressure and the thickness of Homo-MgO films were seriously affected by the ratio of O2/Ar. Moreover, an interesting phenomenon we addressed was the growth mode changed with varying the sputtering power, leading to different surface morphology. Most importantly, apart from Homo-MgO films, our theory can also be appropriate for other oxide films grown by RF magnetic sputtering technology.

Effect of MgO spacer and annealing on interface and magnetic properties of ion beam sputtered NiFe/Mg/MgO/CoFe layer structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhusan Singh, Braj; Chaudhary, Sujeet

2012-09-15

The effect of variation in the thickness of ion assisted ion beam sputtered MgO spacer layer deposited at oxygen ion assisted energy of 50 eV on the extent of magnetic coupling of NiFe and CoFe layers in Si/NiFe(10 nm)/Mg(1 nm)/MgO(2,4,6 nm)/CoFe(10 nm) sandwich structure is investigated. At MgO spacer layer thickness of 4 nm, the separate reversal of magnetizations of the two ferromagnetic layers is observed in the hystresis loop recorded along easy direction. This results in a 3.5 Oe wide plateau like region during magnetization reversal, which became 4.5 Oe at 6 nm thin MgO. At 2 nm thinmore » MgO, the absence of plateau during magnetization reversal region revealed ferromagnetic coupling between the two ferromagnetic layers, which is understood to arise due to the growth of very thin and low density (1.22 gm/cc) MgO spacer layer, indicating the presence of pinholes as revealed by x-ray reflectometry. After vaccum annealing (200 Degree-Sign C/1 h), the plateau region for 4 and 6 nm thin MgO case decreased to 1.5 Oe and 2.0 Oe, respectively, due to enhanced interface roughness/mixing. In addition, an enhancement of the in-plane magnetic anisotropy is also observed.« less

Many Mg-Mg bonds form the core of the Mg16Cp*8Br4K cluster anion: the key to a reassessment of the Grignard reagent (GR) formation process?

PubMed

Kruczyński, T; Henke, F; Neumaier, M; Bowen, K H; Schnöckel, H

2016-02-01

It caused a sensation eight years ago, when the first room temperature stable molecular compound with a Mg-Mg bond (LMgMgL, L = chelating ligand) containing magnesium in the oxidation state +1 was prepared. Here, we report the preparation of a [Mg 16 Cp*8Br 4 K] - cluster anion (Cp* = pentamethylcyclopentadiene) with 27 Mg-Mg bonds. It has been obtained through the reaction of KCp* with a metastable solution of MgBr in toluene. A highly-resolved Fourier transform mass spectrum (FT-MS) of this cluster anion, brought into vacuum by electrospraying its solution in THF, provides the title cluster's stoichiometry. This Mg 16 cluster together with experiments on the metastable solution of MgBr show that: during the formation process of GRs (Grignard reagents) which are involved in most of sophisticated syntheses of organic products, not the highly reactive MgBr radical as often presumed, but instead the metalloid Mg 16 Cp*8Br 4 cluster anion and its related cousins that are the operative intermediates along the pathway from Mg metal to GRs ( e.g. Cp*MgBr).

High-pressure Phase Relation In The MgAl2O4-Mg2SiO4 System

NASA Astrophysics Data System (ADS)

Kojitani, H.; Hisatomi, R.; Akaogi, M.

2005-12-01

High-pressure and high-temperature experiments indicate that high-pressure phases of oceanic basalts contain Al-rich phases. MgAl2O4 with calcium ferrite-type crystal structure is considered as a main component of such the Al-rich phases. Since the calcium ferrite-type MgAl2O4 can be synthesized at only the maximum pressure of a Kawai-type high-pressure apparatus with tungsten carbide (WC) anvils, the amount of a synthesized sample is very limited. Therefore, the crystal structure of the calcium ferrite-type MgAl2O4 has been hardly known in detail due to these difficulties in sample synthesis. In our high-pressure experiments in the MgO-Al2O3-SiO2 system, it was shown that Mg2SiO4 component could be dissolved in the MgAl2O4 calcium ferrite. In this study, we tried to synthesize a single phase MgAl2O4 calcium ferrite sample and to make the Rietveld refinement of the XRD pattern of the sample. The high-pressure phase relations in the MgAl2O4-Mg2SiO4 system were studied to know the stability field of the MgAl2O4-Mg2SiO4 calcium ferrite solid solutions. Lattice parameters-composition relation of the MgAl2O4-Mg2SiO4 calcium ferrite solid solutions was also determined. High-pressure and high-temperature experiments were performed by using a Kawai-type high-pressure apparatus at Gakushuin University. WC anvils with truncated edge length of 1.5 mm were used. Heating was made by a Re heater. Temperature was measured by a Pt/Pt-13%Rh thermocouple. Starting materials for the phase relation experiments were the mixture of MgO, Al2O3 and SiO2 with bulk compositions of MgAl2O4:Mg2SiO4 = 90:10, 78:22, 70:30 and 50:50. The starting materials were held at 21-27 GPa and 1600 °C for 3 hours and then were recovered by the quenching method. The MgAl2O4 calcium ferrite sample for the Rietveld analysis was prepared by heating MgAl2O4 spinel at 27 GPa and about 2200 °C for one hour. Powder X-ray diffraction (XRD) profiles of obtained samples were measured by using a X-ray diffractometer

A systematic study of 25Mg NMR in paramagnetic transition metal oxides: applications to Mg-ion battery materials.

PubMed

Lee, Jeongjae; Seymour, Ieuan D; Pell, Andrew J; Dutton, Siân E; Grey, Clare P

2016-12-21

Rechargeable battery systems based on Mg-ion chemistries are generating significant interest as potential alternatives to Li-ion batteries. Despite the wealth of local structural information that could potentially be gained from Nuclear Magnetic Resonance (NMR) experiments of Mg-ion battery materials, systematic 25 Mg solid-state NMR studies have been scarce due to the low natural abundance, low gyromagnetic ratio, and significant quadrupole moment of 25 Mg (I = 5/2). This work reports a combined experimental 25 Mg NMR and first principles density functional theory (DFT) study of paramagnetic Mg transition metal oxide systems Mg 6 MnO 8 and MgCr 2 O 4 that serve as model systems for Mg-ion battery cathode materials. Magnetic parameters, hyperfine shifts and quadrupolar parameters were calculated ab initio using hybrid DFT and compared to the experimental values obtained from NMR and magnetic measurements. We show that the rotor assisted population transfer (RAPT) pulse sequence can be used to enhance the signal-to-noise ratio in paramagnetic 25 Mg spectra without distortions in the spinning sideband manifold. In addition, the value of the predicted quadrupolar coupling constant of Mg 6 MnO 8 was confirmed using the RAPT pulse sequence. We further apply the same methodology to study the NMR spectra of spinel compounds MgV 2 O 4 and MgMn 2 O 4 , candidate cathode materials for Mg-ion batteries.

Mg-MOF-74/MgF₂ Composite Coating for Improving the Properties of Magnesium Alloy Implants: Hydrophilicity and Corrosion Resistance.

PubMed

Liu, Wei; Yan, Zhijie; Ma, Xiaolu; Geng, Tie; Wu, Haihong; Li, Zhongyue

2018-03-07

Surface modification on Mg alloys is highly promising for their application in the field of bone repair. In this study, a new metal-organic framework/MgF₂ (Mg-MOF-74/MgF₂) composite coating was prepared on the surface of AZ31B Mg alloy via pre-treatment of hydrofluoric acid and in situ hydrothermal synthesis methods. The surface topography of the composite coating is compact and homogeneous, and Mg-MOF-74 has good crystallinity. The corrosion resistance of this composite coating was investigated through Tafel polarization test and immersion test in simulated body fluid at 37 °C. It was found that Mg-MOF-74/MgF₂ composite coating significantly slowed down the corrosion rate of Mg alloy. Additionally, Mg-MOF-74/MgF₂ composite coating expresses super-hydrophilicity with the water contact angle of nearly 0°. In conclusion, on the basis of MgF₂ anticorrosive coating, the introduction of Mg-MOF-74 further improves the biological property of Mg alloys. At last, we propose that the hydrophilicity of the composite coating is mainly owing to the large number of hydroxyl groups, the high specific surface area of Mg-MOF-74, and the rough coating produced by Mg-MOF-74 particles. Hence, Mg-MOF-74 has a great advantage in enhancing the hydrophilicity of Mg alloy surface.

Toward understanding the roaming mechanism in H + MgH → Mg + HH reaction

DOE PAGES

Mauguiere, Frederic A. L.; Collins, Peter; Stamatiadis, Stamatis; ...

2016-02-26

The roaming mechanism in the reaction H + MgH →Mg + HH is investigated by classical and quantum dynamics employing an accurate ab initio threedimensional ground electronic state potential energy surface. The reaction dynamics are explored by running trajectories initialized on a four-dimensional dividing surface anchored on three-dimensional normally hyperbolic invariant manifold associated with a family of unstable orbiting periodic orbits in the entrance channel of the reaction (H + MgH). By locating periodic orbits localized in the HMgH well or involving H orbiting around the MgH diatom, and following their continuation with the total energy, regions in phase spacemore » where reactive or nonreactive trajectories may be trapped are found. In this way roaming reaction pathways are deduced in phase space. Patterns similar to periodic orbits projected into configuration space are found for the quantum bound and resonance eigenstates. Roaming is attributed to the capture of the trajectories in the neighborhood of certain periodic orbits. As a result, the complex forming trajectories in the HMgH well can either return to the radical channel or “roam” to the MgHH minimum from where the molecule may react.« less

Refinements in an Mg/MgH2/H2O-Based Hydrogen Generator

NASA Technical Reports Server (NTRS)

Kindler, Andrew; Huang, Yuhong

2010-01-01

Some refinements have been conceived for a proposed apparatus that would generate hydrogen (for use in a fuel cell) by means of chemical reactions among magnesium, magnesium hydride, and steam. The refinements lie in tailoring spatial and temporal distributions of steam and liquid water so as to obtain greater overall energy-storage or energy-generation efficiency than would otherwise be possible. A description of the prior art is prerequisite to a meaningful description of the present refinements. The hydrogen-generating apparatus in question is one of two versions of what was called the "advanced hydrogen generator" in "Fuel-Cell Power Systems Incorporating Mg-Based H2 Generators" (NPO-43554), NASA Tech Briefs, Vol. 33, No. 1 (January 2009), page 52. To recapitulate: The apparatus would include a reactor vessel that would be initially charged with magnesium hydride. The apparatus would exploit two reactions: The endothermic decomposition reaction MgH2-->Mg + H2, which occurs at a temperature greater than or equal to 300 C, and The exothermic oxidation reaction MgH2 + H2O MgO + 2H2, which occurs at a temperature greater than or equal to 330 C.

Reaction of common bean lines and aggressiveness of Sclerotinia sclerotiorum isolates.

PubMed

Silva, P H; Santos, J B; Lima, I A; Lara, L A C; Alves, F C

2014-11-07

The aims of this study were to evaluate the reaction of common bean lines to white mold, the aggressiveness of different Sclerotinia sclerotiorum isolates from various common bean production areas in Brazil, and comparison of the diallel and GGE (genotype main effect plus genotype-by-environment interaction) biplot analysis procedures via study of the line-by-isolate interaction. Eleven common bean (Phaseolus vulgaris) lines derived from 3 backcross populations were used. Field experiments were performed in the experimental area of the Departamento de Biologia of the Universidade Federal de Lavras, Lavras, MG, Brazil, in the 2011 and 2012 dry crop season and 2011 winter crop season through a randomized block design with 3 replications. This study was also set up in a greenhouse. Inoculations were performed 28 days after sowing by means of the straw test method. The reaction of the bean lines to white mold was assessed according to a diagrammatic scale from 1 (plant without symptoms) to 9 (dead plant). Estimations of general reaction capacity (lines) and general aggressiveness capacity (isolates) indicated different horizontal levels of resistance in the lines and levels of aggressiveness in the isolates. Therefore, it was possible to select more resistant lines and foresee those crosses that are the most promising for increasing the level of resistance. It was also possible to identify the most aggressive isolates that were more efficient in distinguishing the lines. Both diallel and GGE biplot analyses were useful in identifying the genotypic values of lines and isolates.

Uncovering the Local Magnesium Environment in the Metal–Organic Framework Mg 2 (dobpdc) Using 25 Mg NMR Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Jun; Blaakmeer, E. S. Merijn; Lipton, Andrew S.

The incorporation of N,N'-dimethylethylenediamine into an expanded MOF-74 framework has yielded a material (mmen-Mg2(dobpdc)) exhibiting “step-shaped” CO2 adsorption isotherms. The coordination of mmen at the Mg open metal center is essential for the unique cooperative adsorption mechanism elucidated for this material. Despite its importance for carbon capture, there is as yet no experimental structure determination available for the underlying metal– organic framework Mg2(dobpdc). Our 25Mg solid-state NMR data unravel the local Mg environments in several Mg2(dobpdc) samples, unambiguously confirming the formation of fivecoordinate Mg centers in the activated material and six-coordinate Mg centers in the solvent- or diamine-loaded samples, suchmore » as mmen-Mg2(dobpdc). A fraction of the Mg centers are locally disordered due to the framework deformation accompanied by the guest distributions and dynamics.« less

Zolpidem 10 mg given at daytime is not antagonized by 300 mg caffeine in man.

PubMed

Mattila, M J; Nurminen, M L; Vainio, P; Vanakoski, J

1998-07-01

Caffeine counteracts various effects of traditional benzodiazepines (BZDs). As zolpidem, a short-acting hypnotic, is an atypical GABAA-BZD agonist, we investigated when caffeine would counteract the effects of zolpidem as well. In daytime study I, zolpidem 10 mg (capsule) and caffeine 150 or 300 mg (in decaffeinated coffee) were given, alone and in combinations, to parallel groups (n = 15-17) of healthy students in double-blind and placebo-controlled manner. Objective and subjective tests were done before and 45 min and 90 min after intake. Ranked delta values (changes from baseline) were analysed by one-way contrast ANOVA and Scheffe's tests. In daytime study II, four healthy subjects took zolpidem 10 mg alone, and together with blinded caffeine 250 mg or (at -45 min) erythromycin 750 mg. Objective and subjective effects were measured and plasma zolpidem concentrations assayed at baseline and 45 min and 90 min after zolpidem intake. In study I, practice effects after placebo (ad + 30%) were seen for letter cancellation and digit symbol substitution but not for flicker fusion tests. Zolpidem alone significantly impaired (P < 0.05 vs delta placebo) letter cancellation and digit symbol substitution at 45 min and 90 min, lowered the flicker fusion threshold at 45 min, and caused subjective drowsiness, mental slowness, clumsiness and feeling of poor performance. Caffeine alone showed a non-significant trend to improve objective performance. The combined effects of zolpidem and either dose of caffeine matched those measured after zolpidem alone. Zolpidem + caffeine 300 mg was not stronger than zolpidem + caffeine 150 mg in impairing immediate memory and causing subjective sedation. In study II, zolpidem caused objective and subjective sedation; neither caffeine nor erythromycin modulated the effects of zolpidem or plasma zolpidem concentrations. The sedative effects of 10 mg of zolpidem are not antagonized by 150-300 mg of caffeine in pharmacodynamic or pharmacokinetic

Prevalence and Factors Associated with Intimate Partner Violence among Married Women in an Urban Community in Lagos State, Nigeria.

PubMed

Onigbogi, Modupe O; Odeyemi, Kofoworola A; Onigbogi, Olanrewaju O

2015-03-01

Violence against women is a major public health problem globally. A cross-sectional descriptive study was conducted in Ikosi Isheri LCDA of Lagos State among 400 married women. A multistage sampling method was used to select the respondents. The lifetime prevalence for physical violence, sexual violence and psychological violence were 50.5%, 33.8% and 85.0% respectively. Predictive factors for physical IPV include lower educational status of the women (AOR 3.22 95% CI: 1.54-6.77) and partner's daily alcohol intake (AOR: 1.84 95% CI: 1.05-3.23). The predictors of sexual violence include unemployment status of the partners (OR 5.89:1.39-24.84) and daily/weekly alcohol use (AOR 1.87 95% CI: 1.05-3.33). Predictors of psychological violence include respondents witness of parental violence (AOR 2.80 95% CI: 1.04-7.5) and daily alcohol use by partners (AOR 2.71 95% CI: 1.19-6.18). Preventive interventions such as increasing the educational status of women and reducing the intake of alcohol by men may help break the cycle of abuse.

Mechanism of magnetoresistance ratio enhancement in MgO/NiFe/MgO heterostructure by rapid thermal annealing

NASA Astrophysics Data System (ADS)

Zhao, Chong-Jun; Liu, Yang; Zhang, Jing-Yan; Sun, Li; Ding, Lei; Zhang, Peng; Wang, Bao-Yi; Cao, Xing-Zhong; Yu, Guang-Hua

2012-08-01

To reveal thermal effects on the film quality/microstructure evolution and the resulted magnetoresistance (MR) ratio in MgO/NiFe/MgO heterostructures, positron annihilation spectroscopy studies have been performed. It is found that the ionic interstitials in the MgO layers recombine with the nearby vacancies at lower annealing temperatures (200-300 °C) and lead to a slow increase in sample MR. Meanwhile, vacancy defects agglomeration/removal and ordering acceleration in MgO will occur at higher annealing temperatures (450-550 °C) and the improved MgO and MgO/NiFe interfaces microstructure are responsible for the observed significant MR enhancement.

Efficacy and tolerability of the single-pill combination of aliskiren 300 mg/amlodipine 10 mg in hypertensive patients not controlled by olmesartan 40 mg/amlodipine 10 mg.

PubMed

Axthelm, Christoph; Sieder, Christian; Meister, Franziska; Kaiser, Edelgard

2012-01-01

We aimed to investigate whether the single pill combination (SPC) of aliskiren 300 mg and amlodipine 10 mg (ALIS 300/AMLO 10) improves blood pressure (BP) reduction in hypertensive patients not adequately controlled by the SPC olmesartan 40 mg and amlodipine 10 mg (OLM 40/AMLO 10). Open-label, non-randomized single-arm study. Patients with stage 2 hypertension were titrated to the SPC OLM 40/AMLO 10 (4-week Phase 1). If hypertension was not controlled they were switched to the SPC ALIS 300/AMLO 10 (4-week Phase 2). In the optional 4-week study extension hydrochlorothiazide (HCT) 12.5 mg was added. EudraCT 2009-016693-33. In the 342 patients treated, OLM 40/AMLO 10 reduced systolic BP (SBP)/diastolic BP (DBP) by 24.5/14.5 mmHg by end of Phase 1. Those 187 patients with uncontrolled hypertension at the end of Phase 1 switched to ALIS 300/AMLO 10 experienced a further SBP reduction of 5.1 mmHg (95% confidence interval [CI] 3.7 to 6.5, p < 0.0001) and a DBP reduction of 4.8 mmHg (95% CI 3.8 to 5.8; p < 0.0001) in Phase 2. DBP or SBP responder rates were achieved by 51.3% or 44.4%, respectively, SBP and DBP normalization by 36.4%. In 65 patients whose BP was not controlled in Phase 2, SPC ALIS 300/AMLO 10/HCT 12.5 mg decreased SBP/DBP by further 8.1/6.7 mmHg (p < 0.0001 each). No deaths or serious adverse events were noted. Significant adverse events leading to study discontinuation were reported in 2.6% (Phase 1), 2.7% (Phase 2), and 0% (extension). Limitations included the open-label, single-arm non-randomized design, and the relatively short duration. In this switch study reflecting clinical practice, patients with moderate hypertension not controlled by the SPC OLM 40/AMLO 10 achieved a clinically and statistically significant reduction of blood pressure from the SPC ALIS 300/AMLO 10 and the optional addition of HCT. All drug combinations were well tolerated.

Alterations of Mg2+ After Hemorrhagic Shock.

PubMed

Lee, Mun-Young; Yang, Dong Kwon; Kim, Shang-Jin

2017-11-01

Hemorrhagic shock is generally characterized by hemodynamic instability with cellular hypoxia and diminishing cellular function, resulting from an imbalance between systemic oxygen delivery and consumption and redistribution of fluid and electrolytes. Magnesium (Mg) is the fourth most abundant cation overall and second most abundant intracellular cation in the body and an essential cofactor for the energy production and cellular metabolism. Data for blood total Mg (tMg; free-ionized, protein-bound, and anion-bound forms) and free Mg 2+ levels after a traumatic injury are inconsistent and only limited information is available on hemorrhagic effects on free Mg 2+ as the physiologically active form. The aim of this study was to determine changes in blood Mg 2+ and tMg after hemorrhage in rats identifying mechanism and origin of the changes in blood Mg 2+ . Hemorrhagic shock produced significant increases in blood Mg 2+ , plasma tMg, Na + , K + , Cl - , anion gap, partial pressures of oxygen, glucose, and blood urea nitrogen but significant decreases in RBC tMg, blood Ca 2+ , HCO 3 - , pH, partial pressures of carbon dioxide, hematocrit, hemoglobin, total cholesterol, and plasma/RBC ATP. During hemorrhagic shock, K + , anion gap, and BUN showed significant positive correlations with changes in blood Mg 2+ level, while Ca 2+ , pH, and T-CHO correlated to Mg 2+ in a negative manner. In conclusion, hemorrhagic shock induced an increase in both blood-free Mg 2+ and tMg, resulted from Mg 2+ efflux from metabolic damaged cell with acidosis and ATP depletion.

High-Capacity Mg-Organic Batteries Based on Nanostructured Rhodizonate Salts Activated by Mg-Li Dual-Salt Electrolyte.

PubMed

Tian, Jing; Cao, Dunping; Zhou, Xuejun; Hu, Jiulin; Huang, Minsong; Li, Chilin

2018-04-24

A magnesium battery is a promising candidate for large-scale transportation and stationary energy storage due to the security, low cost, abundance, and high volumetric energy density of a Mg anode. But there are still some obstacles retarding the wide application of Mg batteries, including poor kinetics of Mg-ion transport in lattices and low theoretical capacity in inorganic frameworks. A Mg-Li dual-salt electrolyte enables kinetic activation by dominant intercalation of Li-ions instead of Mg-ions in cathode lattices without the compromise of a stable Mg anode process. Here we propose a Mg-organic battery based on a renewable rhodizonate salt ( e. g., Na 2 C 6 O 6 ) activated by a Mg-Li dual-salt electrolyte. The nanostructured organic system can achieve a high reversible capacity of 350-400 mAh/g due to the existence of high-density carbonyl groups (C═O) as redox sites. Nanocrystalline Na 2 C 6 O 6 wired by reduced graphene oxide enables a high-rate performance of 200 and 175 mAh/g at 2.5 (5 C) and 5 A/g (10 C), respectively, which also benefits from a high intrinsic diffusion coefficient (10 -12 -10 -11 cm 2 /s) and pesudocapacitance contribution (>60%) of Na 2 C 6 O 6 for Li-Mg co-intercalation. The suppressed exfoliation of C 6 O 6 layers by a firmer non-Li pinning via Na-O-C or Mg-O-C and a dendrite-resistive Mg anode lead to a long-term cycling for at least 600 cycles. Such an extraordinary capacity/rate performance endows the Mg-Na 2 C 6 O 6 system with high energy and power densities up to 525 Wh/kg and 4490 W/kg (based on active cathode material), respectively, exceeding the level of high-voltage insertion cathodes with typical inorganic structures.

Kinetic analysis of MgB2 layer formation in advanced internal magnesium infiltration (AIMI) processed MgB2 wires

PubMed Central

Li, G. Z.; Sumption, M. D.; Collings, E. W.

2015-01-01

Significantly enhanced critical current density (Jc) for MgB2 superconducting wires can be obtained following the advanced internal Mg infiltration (AIMI) route. But unless suitable precautions are taken, the AIMI-processed MgB2 wires will exhibit incomplete MgB2 layer formation, i.e. reduced superconductor core size and hence suppressed current-carrying capability. Microstructural characterization of AIMI MgB2 wires before and after the heat treatment reveals that the reaction mechanism changes from a “Mg infiltration-reaction” at the beginning of the heat treatment to a “Mg diffusion-reaction” once a dense MgB2 layer is formed. A drastic drop in the Mg transport rate from infiltration to diffusion causes the termination of the MgB2 core growth. To quantify this process, a two-stage kinetic model is built to describe the MgB2 layer formation and growth. The derived kinetic model and the associated experimental observations indicate that fully reacted AIMI-processed MgB2 wires can be achieved following the optimization of B particle size, B powder packing density, MgB2 reaction activation energy and its response to the additions of dopants. PMID:26973431

Porous Ceramic Composite ZrO2(MgO)-MgO for Osteoimplantology

NASA Astrophysics Data System (ADS)

Buyakov, A. S.; Kulkov, S. N.

2017-02-01

Pore and crystalline structure, biocompatibility of ceramic composite ZrO2(MgO)-MgO were studied. The main mechanical characteristics were determined and it has been shown that compression strength directly depends on microstresses obtained from X-ray data. In-vitro studies of mesenchymal stromal stem cells (MMSC), cultivated on material surface are shown that cell proliferation and differentiation of MMSC goes throw osteogenic type.

Bioequivalence of a single 400-mg dose of imatinib 100-mg oral tablets and a 400-mg tablet in healthy adult Korean volunteers.

PubMed

Lee, Hae Won; Seong, Sook Jin; Park, Sung Min; Lee, Joomi; Gwon, Mi-Ri; Kim, Hyun-Ju; Lim, Sung Mook; Lim, Mi-Sun; Kim, Woomi; Yang, Dong Heon; Yoon, Young-Ran

2015-06-01

Imatinib mesylate (IM) is a selective tyrosine kinase inhibitor for the treatment of chronic myeloid leukemia and gastrointestinal stromal tumors. A new once-daily 400-mg film-coated tablet of imatinib has been developed by a pharmaceutical company in Korea. The present study was designed to assess and compare the PK parameters, bioavailability, and bioequivalence of the new imatinib 400-mg formulation (test) versus the conventional 100-mg formulation (reference) administered as a single 400-mg dose in healthy adult male volunteers. This randomized, open-label, single-dose, two-way crossover study was conducted in healthy Korean male volunteers. Eligible subjects were randomly assigned in a 1 : 1 ratio to receive 400 mg of the test (one 400-mg tablet) or reference (four 100-mg tablets) formulation, followed by a 2-week washout period and administration of the alternate formulation. Serial blood samples were collected at 0 (predose), 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 24, 48, and 72 hours after administration. Plasma imatinib concentrations were determined using liquid chromatography coupled with tandem mass spectrometry. The formulations were to be considered bioequivalent if the 90% confidence intervals (CIs) of the adjusted geometric mean ratios for Cmax, AUC(0-t), and AUC(0-∞)ž were within the predetermined range of 0.80 - 1.25. In total, 35 subjects completed the study. No serious adverse event was reported during the study. The 90% CIs of the adjusted geometric mean ratios of the test formulation to the reference formulation for C(max), AUC(0-t) and AUC(0-∞)ž of imatinib were all within the bioequivalence criteria range of 0.8 - 1.25. The test formulation of imatinib met the Korean regulatory requirements for bioequivalence. Both imatinib formulations were well-tolerated in all subjects.

Mg-MOF-74/MgF2 Composite Coating for Improving the Properties of Magnesium Alloy Implants: Hydrophilicity and Corrosion Resistance

PubMed Central

Liu, Wei; Yan, Zhijie; Ma, Xiaolu; Geng, Tie; Wu, Haihong

2018-01-01

Surface modification on Mg alloys is highly promising for their application in the field of bone repair. In this study, a new metal–organic framework/MgF2 (Mg-MOF-74/MgF2) composite coating was prepared on the surface of AZ31B Mg alloy via pre-treatment of hydrofluoric acid and in situ hydrothermal synthesis methods. The surface topography of the composite coating is compact and homogeneous, and Mg-MOF-74 has good crystallinity. The corrosion resistance of this composite coating was investigated through Tafel polarization test and immersion test in simulated body fluid at 37 °C. It was found that Mg-MOF-74/MgF2 composite coating significantly slowed down the corrosion rate of Mg alloy. Additionally, Mg-MOF-74/MgF2 composite coating expresses super-hydrophilicity with the water contact angle of nearly 0°. In conclusion, on the basis of MgF2 anticorrosive coating, the introduction of Mg-MOF-74 further improves the biological property of Mg alloys. At last, we propose that the hydrophilicity of the composite coating is mainly owing to the large number of hydroxyl groups, the high specific surface area of Mg-MOF-74, and the rough coating produced by Mg-MOF-74 particles. Hence, Mg-MOF-74 has a great advantage in enhancing the hydrophilicity of Mg alloy surface. PMID:29518933

Adsorption of arginine, glycine and aspartic acid on Mg and Mg-based alloy surfaces: A first-principles study

NASA Astrophysics Data System (ADS)

Fang, Zhe; Wang, Jianfeng; Yang, Xiaofan; Sun, Qiang; Jia, Yu; Liu, Hairong; Xi, Tingfei; Guan, Shaokang

2017-07-01

Studying the adsorption behaviors of biomolecules on the surface of Mg and Mg-based alloy has a fundamental and important role for related applications in biotechnology. In the present work, we systematically investigate and compare the adsorption properties of three typical amino acids, i.e., Arg (arginine), Gly (glycine) and Asp (aspartic acid), which form RGD tripeptide, on the Mg (0 0 0 1) surface with various doping (Zn, Y, and Nd), and aim to realize proper binding between biomolecules and Mg and Mg-based biomedical materials. Our results show that flat adsorption configurations of the functional groups binding to the surfaces are favored in energy for all the three selected amino acids. In specific, for the amino acids adsorped on clean Mg (0 0 0 1) surface, the adsorption energy (Eads) of Arg is found to be -1.67 eV for the most stable configuration, with amino and guanidyl groups binding with the surface. However, Gly (Asp) is found to binding with the surface through amino and carboxyl groups, with a -1.16 eV (-1.15 eV) binding energy. On the 2% Zn doped Mg (0 0 0 1) alloy surface (Mg-Zn (2%)), the Eads are significantly increased to be -1.91 eV, -1.32 eV and -1.35 eV for Arg, Gly and Asp, respectively. While the Mg-Y (1%) and Mg-Nd (1%) slightly weaken the adsorption of three amino acids. Moreover, we have performed detail discussions of the binding properties between amino acids and surfaces by projected density of states (PDOS) combined with charge transfer analyses. Our studies provide a comprehensive understanding on the interactions between amino acids and Mg and Mg-based alloy surfaces, with respect to facilitate the applications of Mg and Mg-based biomedical alloys in biosensing, drug delivery, biomolecule coating and other fields in biotechnology.

Pattern of Injuries in Fatal Motorcycle Accidents Seen in Lagos State University Teaching Hospital: An Autopsy-Based Study.

PubMed

Faduyile, Francis; Emiogun, Festus; Soyemi, Sunday; Oyewole, Olugbenga; Okeke, Uche; Williams, Oluseun

2017-04-15

Deaths from motorcycle accident injuries have remained a major public health issue in Nigeria over the years. The study is to determine the age and gender distribution of the victims and to identify the cause of death and the anatomical pattern of injuries seen. This is a 5-year autopsy-based study of all motorcycle accident deaths seen in Lagos State University Teaching Hospital between December 2009 and November 2014. The data were retrieved from autopsy reports, hospital case notes extracts from police diary and were analysed using SPSS version 20. Motorcycle accidents accounted for 156 (2.8%) of all the autopsies done (5,661), and 156 (18.4%) of all Road Traffic Accidents (RTA) autopsies (849) performed over the study period, with a male: female ratio of 6:1. The peak age of victims was 31-40 years (30.9%). Head injuries accounted for most (41.4%) of the injuries seen, and the majority of the victims died of craniocerebral injury 53 (50.7%). This study showed that males in the fourth decade of life are the major victims of motorcycle accident death. The majority of the victims were the rider of the motorcycle. Most of them died of the craniocerebral injury.

Pattern of Injuries in Fatal Motorcycle Accidents Seen in Lagos State University Teaching Hospital: An Autopsy-Based Study

PubMed Central

Faduyile, Francis; Emiogun, Festus; Soyemi, Sunday; Oyewole, Olugbenga; Okeke, Uche; Williams, Oluseun

2017-01-01

BACKGROUND: Deaths from motorcycle accident injuries have remained a major public health issue in Nigeria over the years. AIM: The study is to determine the age and gender distribution of the victims and to identify the cause of death and the anatomical pattern of injuries seen. METHODOLOGY: This is a 5-year autopsy-based study of all motorcycle accident deaths seen in Lagos State University Teaching Hospital between December 2009 and November 2014. The data were retrieved from autopsy reports, hospital case notes extracts from police diary and were analysed using SPSS version 20. RESULTS: Motorcycle accidents accounted for 156 (2.8%) of all the autopsies done (5,661), and 156 (18.4%) of all Road Traffic Accidents (RTA) autopsies (849) performed over the study period, with a male: female ratio of 6:1. The peak age of victims was 31-40 years (30.9%). Head injuries accounted for most (41.4%) of the injuries seen, and the majority of the victims died of craniocerebral injury 53 (50.7%). CONCLUSION: This study showed that males in the fourth decade of life are the major victims of motorcycle accident death. The majority of the victims were the rider of the motorcycle. Most of them died of the craniocerebral injury. PMID:28507612

Evaluation of haematological, hepatic and renal functions of petroleum tanker drivers in Lagos, Nigeria.

PubMed

Awodele, Olufunsho; Sulayman, Ademola A; Akintonwa, Alade

2014-03-01

Hydrocarbons which are among the major components of petroleum products are considered toxic and have been implicated in a number of human diseases. Tanker drivers are continuously exposed to hydrocarbons by inhalation and most of these drivers do not use protective devices to prevent inhalation of petroleum products; nor do they visit hospital regularly for routine check-up. In view of this occupational hazard, we investigated the haematological, renal and hepatic functions of workers of petroleum tankers drivers in Lagos, Nigeria. Twenty-five tanker drivers' and fifteen control subjects were randomly selected based on the selection criteria of not smoking and working for minimum of 5 years as petroleum tanker driver. The liver, renal and haematological parameters were analyzed using automated clinical and haematological analyzers while the lipid peroxidation and antioxidant level tests were assayed using standard methods. There were significant (p ≤ 0.05) increases in the levels of serum alanine amino transferase (31.14±13.72; 22.38±9.89), albumin (42.50±4.69; 45.36±1.74) and alkaline phosphatase (84.04±21.89; 62.04±23.33) of petroleum tanker drivers compared with the controls. A significant (p≤0.05) increase in the levels of creatinine, urea and white blood cells of the tanker drivers, compared with the controls, were also obtained. The results have enormous health implications of continuous exposure to petroleum products reflected hepatic and renal damage of petroleum tanker drivers. Therefore, there is need for this group of workers to be sensitized on the importance of protective devises, regular medical checkup and management.

Prevalence of cardiometabolic risk factors among professional male long-distance bus drivers in Lagos, south-west Nigeria: a cross-sectional study.

PubMed

Amadi, Casmir E; Grove, Tim P; Mbakwem, Amam C; Ozoh, Obianuju B; Kushimo, Oyewole A; Wood, David A; Akinkunmi, Michael

Professional drivers are known to be at high risk of cardiovascular disease (CVD). This study was carried out to highlight these risk factors and their predictors among male long-distance professional bus drivers in Lagos, south-west Nigeria, with a view to improving health awareness in this group. Socio-demographic data, anthropometric indices, blood pressure, fasting plasma blood glucose levels and lipid and physical activity profiles of 293 drivers were measured. Mean age of the study population was 48 ± 9.7 years; 71.0 and 19.5% of the drivers used alcohol and were smokers, respectively; and 50.9% were physically inactive. The prevalence of overweight and obesity was 41.7 and 21.1%, respectively, while 39.7 and 13.9% were hypertensive and diabetic, respectively. Ninety (31.3%) subjects had impaired fasting glucose levels while 56.3% had dyslipidaemia. Predictors of hypertension were age and body mass index (BMI). BMI only was a predictor of abnormal glucose profile. Professional male long-distance bus drivers in this study showed a high prevalence of a cluster of risk factors for CVD.

Critical current densities of powder-in-tube MgB2 tapes fabricated with nanometer-size Mg powder

NASA Astrophysics Data System (ADS)

Yamada, H.; Hirakawa, M.; Kumakura, H.; Matsumoto, A.; Kitaguchi, H.

2004-03-01

We fabricated powder-in-tube MgB2/Fe tapes using a powder mixture of nanometer-size Mg and commercial amorphous B and investigated the transport properties. High-purity nanometer-size Mg powder was fabricated by applying the thermal plasma method. 5-10 mol % SiC powder doping was tried to enhance the Jc properties. We found that the use of nanometer-size Mg powder was effective to increase the Jc values. The transport Jc values of the nondoped and 10 mol % SiC-doped tapes prepared with nanometer-size Mg powder reached 90 and 250 A/mm2 at 4.2 K and 10 T, respectively. These values were about five times higher than those of the tapes prepared with commercial Mg powder.

Apollo 15 Mg- and Fe-norites - A redefinition of the Mg-suite differentiation trend

NASA Technical Reports Server (NTRS)

Lindstrom, M. M.; Marvin, U. B.; Mittlefehldt, D. W.

1989-01-01

The Apollo 15 highland rocks from the Apennine Front include clasts of mafic plutonic rocks from deep in the lunar crust that were brought to the surface by the Imbrium and Serenitatis impacts. The Apollo 15 norites exhibit wide variations in mineral and bulk compositions and include Fe-norites that plot between the three major pristine rock fields on a diagram of Mg' in mafic minerals vs An in paglioclase. Based on assemblages and compositions of minerals, and on ratios of elemental abundances, it is concluded that these Apollo 15 Fe-norites are differentiated members of the Mg-norite suite. The Apollo 15 and 17 norites and troctolites form a closely related suite of rocks, whose variations in mineral compositions represent the main differentiation trend of the Mg-suite. This trend in mineral compositions has a steeper slope than the previous Mg-suite field. The parent magmas for these Mg-suite rocks formed by partial melting deep in the lunar mantle. Differentiation by fractional crystallization may also have included assimilation of crustal components as the magmas rose from the mantle and crystallized plutons in the lower crust.

Assessment of medical waste management in seven hospitals in Lagos, Nigeria.

PubMed

Awodele, Olufunsho; Adewoye, Aishat Abiodun; Oparah, Azuka Cyril

2016-03-15

Medical waste (MW) can be generated in hospitals, clinics and places where diagnosis and treatment are conducted. The management of these wastes is an issue of great concern and importance in view of potential public health risks associated with such wastes. The study assessed the medical waste management practices in selected hospitals and also determined the impact of Lagos Waste Management Authority (LAWMA) intervention programs. A descriptive cross-sectional survey method was used. Data were collected using three instrument (questionnaire, site visitation and in -depth interview). Two public (hospital A, B) and five private (hospital C, D, E, F and G) which provide services for low, middle and high income earners were used. Data analysis was done with SPSS version 20. Chi-squared test was used to determine level of significance at p < 0.05. The majority 56 (53.3%) of the respondents were females with mean age of 35.46 (±1.66) years. The hospital surveyed, except hospital D, disposes both general and medical waste separately. All the facilities have the same process of managing their waste which is segregation, collection/on-site transportation, on-site storage and off-site transportation. Staff responsible for collecting medical waste uses mainly hand gloves as personal protective equipment. The intervention programs helped to ensure compliance and safety of the processes; all the hospitals employ the services of LAWMA for final waste disposal and treatment. Only hospital B offered on-site treatment of its waste (sharps only) with an incinerator while LAWMA uses hydroclave to treat its wastes. There are no policies or guidelines in all investigated hospitals for managing waste. An awareness of proper waste management amongst health workers has been created in most hospitals through the initiative of LAWMA. However, hospital D still mixes municipal and hazardous wastes. The treatment of waste is generally done by LAWMA using hydroclave, to prevent environmental

Cooking Fuels in Lagos, Nigeria: Factors Associated with Household Choice of Kerosene or Liquefied Petroleum Gas (LPG)

PubMed Central

Okwor, Tochi J.; Adetona, Olorunfemi; Akinkugbe, Ayesha O.; Amadi, Casmir E.; Esezobor, Christopher; Adeyeye, Olufunke O.; Ojo, Oluwafemi; Nwude, Vivian N.; Mortimer, Kevin

2018-01-01

Cooking with dirty-burning fuels is associated with health risk from household air pollution. We assessed the prevalence of and factors associated with the use of cooking fuels, and attitudes and barriers towards use of liquefied petroleum gas (LPG). This was a cross-sectional, population-based survey conducted in 519 households in Lagos, Nigeria. We used a structured questionnaire to obtain information regarding choice of household cooking fuel and the attitudes towards the use of LPG. Kerosene was the most frequently used cooking fuel (n = 475, 91.5%; primary use n = 364, 70.1%) followed by charcoal (n = 159, 30.6%; primary use n = 88, 17%) and LPG (n = 86, 16.6%; primary use n = 63, 12.1%). Higher level of education, higher income and younger age were associated with LPG vs. kerosene use. Fuel expenditure on LPG was significantly lower than for kerosene (N (Naira) 2169.0 ± 1507.0 vs. N2581.6 ± 1407.5). Over 90% of non-LPG users were willing to switch to LPG but cited safety issues and high cost as potential barriers to switching. Our findings suggest that misinformation and beliefs regarding benefits, safety and cost of LPG are important barriers to LPG use. An educational intervention program could be a cost-effective approach to improve LPG adoption and should be formally addressed through a well-designed community-based intervention study. PMID:29614713

Cooking Fuels in Lagos, Nigeria: Factors Associated with Household Choice of Kerosene or Liquefied Petroleum Gas (LPG).

PubMed

Ozoh, Obianuju B; Okwor, Tochi J; Adetona, Olorunfemi; Akinkugbe, Ayesha O; Amadi, Casmir E; Esezobor, Christopher; Adeyeye, Olufunke O; Ojo, Oluwafemi; Nwude, Vivian N; Mortimer, Kevin

2018-03-31

Cooking with dirty-burning fuels is associated with health risk from household air pollution. We assessed the prevalence of and factors associated with the use of cooking fuels, and attitudes and barriers towards use of liquefied petroleum gas (LPG). This was a cross-sectional, population-based survey conducted in 519 households in Lagos, Nigeria. We used a structured questionnaire to obtain information regarding choice of household cooking fuel and the attitudes towards the use of LPG. Kerosene was the most frequently used cooking fuel ( n = 475, 91.5%; primary use n = 364, 70.1%) followed by charcoal ( n = 159, 30.6%; primary use n = 88, 17%) and LPG ( n = 86, 16.6%; primary use n = 63, 12.1%). Higher level of education, higher income and younger age were associated with LPG vs. kerosene use. Fuel expenditure on LPG was significantly lower than for kerosene ( N (Naira) 2169.0 ± 1507.0 vs. N 2581.6 ± 1407.5). Over 90% of non-LPG users were willing to switch to LPG but cited safety issues and high cost as potential barriers to switching. Our findings suggest that misinformation and beliefs regarding benefits, safety and cost of LPG are important barriers to LPG use. An educational intervention program could be a cost-effective approach to improve LPG adoption and should be formally addressed through a well-designed community-based intervention study.

Glacier Grey view from Lago Grey (Grey Lake), photographed during NASA's AirSAR 2004 campaign in Chile

NASA Image and Video Library

2004-03-11

Glacier Grey view from Lago Grey (Grey Lake), photographed during NASA's AirSAR 2004 campaign in Chile. Land visible in this photo was covered by glacier just 6 years earlier. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. Founded in 1959, Torres del Paine National Park encompasses 450,000 acres in the Patagonia region of Chile. This region is being studied by NASA using a DC-8 equipped with an Airborne Synthetic Aperture Radar (AirSAR) developed by scientists from NASA’s Jet Propulsion Laboratory. This is a very sensitive region that is important to scientists because the temperature has been consistently rising causing a subsequent melting of the region’s glaciers. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

Sustainable poverty amelioration through early life education in a peri-urban community of Lagos, Nigeria

PubMed Central

Campbell, Princess C.; Okechukwu, Emmanuel I.; Salako-Akande, Ajibike O.; Onyenwenyi, Anthonia O.

2010-01-01

ABSTRACT Background Daycare centres/nurseries have become popular because of the need for working mothers to leave young children with caregivers. However, the high poverty level (54% relative and 35% extreme poverty) makes it difficult for disadvantaged parents to pay the high fees charged by the centres. This study describes an attempt to economically empower mothers through the organisation of free early life education in a peri-urban community in Lagos. Objectives The aim of the study was to examine early life education for under-fives as a means of economic empowerment of mothers and sustainable poverty amelioration. Method The methodology included a non-randomised selection of 34 disadvantaged mothers by criteria, a prospective intervention utilising community resources to organise early childhood education, an in-depth interview of mothers, and observation of the outcomes over a 5-year period. Results The result of the study showed that no mother preferred keeping a child older than three years at home. Access to early childhood education gave mothers opportunity to undergo vocational training (1, 2.8%) and take up new/additional jobs (12, 35.3%). All mothers and 32 (80%) of the participating families more than doubled their income, earning up to twenty thousand Naira (approximately $182) per month from the first year of participation. Finally, selection criteria and periodic assessment of immunisation/growth monitoring records of participants’ children improved compliance with primary health care service utilisation. Conclusion Organisation of early childhood education had the potential for sustainable poverty amelioration through economic empowerment of mothers.

The prevalence and risk factors for Trichomonas vaginalis infection amongst human immunodeficiency virus-infected pregnant women attending the antenatal clinics of a university teaching hospital in Lagos, South-Western, Nigeria.

PubMed

Ijasan, Olaolopin; Okunade, Kehinde Sharafadeen; Oluwole, Ayodeji Ayotunde

2018-01-01

Trichomonas vaginalis infection is the most prevalent non-viral sexually transmitted infection worldwide. Interactions between this infection and human immunodeficiency virus (HIV) may cause adverse pregnancy outcomes such as preterm labour, premature rupture of membranes, chorioamnionitis, low birth weight and post-abortal sepsis. This study was aimed to determine the prevalence and risk factors of T. vaginalis infection amongst HIV-positive pregnant women attending antenatal care at the Lagos University Teaching Hospital (LUTH), Lagos, Nigeria. This was an analytical cross-sectional study in which 320 eligible participants which included 160 HIV-positive (case group) and 160 HIV-negative (control group) pregnant women were recruited at the antenatal clinic of LUTH. A structured pro forma was used to collect data from consenting participants after which high vaginal swabs were collected, processed and examined for T. vaginalis. The association between categorical variables was tested using the Chi-square test and Fisher's exact test where applicable. All significances were reported at P < 0.05. The prevalence of T. vaginalis infection amongst HIV-positive and HIV-negative pregnant women were 10% and 8.1%, respectively (P = 0.559). Significant risk factors for T. vaginalis infection in the HIV-positive pregnant women were early coitarche (P < 0.005) and multiple lifetime sexual partners (P = 0.021). There was no relationship between the T. vaginalis infection and the immunological markers of HIV infection. While this study does not provide grounds for universal screening of pregnant women for T. vaginalis infection as a tool of reducing HIV acquisition, especially in pregnancy, campaign to create better sexual health awareness should be commenced as a way to contributing to the reduction in T. vaginalis infection during pregnancy and perinatal transmission of HIV.

Enhanced voltage-controlled magnetic anisotropy in magnetic tunnel junctions with an MgO/PZT/MgO tunnel barrier

NASA Astrophysics Data System (ADS)

Chien, Diana; Li, Xiang; Wong, Kin; Zurbuchen, Mark A.; Robbennolt, Shauna; Yu, Guoqiang; Tolbert, Sarah; Kioussis, Nicholas; Khalili Amiri, Pedram; Wang, Kang L.; Chang, Jane P.

2016-03-01

Compared with current-controlled magnetization switching in a perpendicular magnetic tunnel junction (MTJ), electric field- or voltage-induced magnetization switching reduces the writing energy of the memory cell, which also results in increased memory density. In this work, an ultra-thin PZT film with high dielectric constant was integrated into the tunneling oxide layer to enhance the voltage-controlled magnetic anisotropy (VCMA) effect. The growth of MTJ stacks with an MgO/PZT/MgO tunnel barrier was performed using a combination of sputtering and atomic layer deposition techniques. The fabricated MTJs with the MgO/PZT/MgO barrier demonstrate a VCMA coefficient, which is ˜40% higher (19.8 ± 1.3 fJ/V m) than the control sample MTJs with an MgO barrier (14.3 ± 2.7 fJ/V m). The MTJs with the MgO/PZT/MgO barrier also possess a sizeable tunneling magnetoresistance (TMR) of more than 50% at room temperature, comparable to the control MTJs with an MgO barrier. The TMR and enhanced VCMA effect demonstrated simultaneously in this work make the MgO/PZT/MgO barrier-based MTJs potential candidates for future voltage-controlled, ultralow-power, and high-density magnetic random access memory devices.

[Utility of treatment with atorvastatin 40 mg plus ezetimibe 10 mg versus atorvastatin 80 mg in reducing the levels of LDL cholesterol in patients with ischaemic stroke or transient ischaemic attack].

PubMed

Palacio, Enrique; Viadero-Cervera, Raquel; Revilla, Marián; Larrosa-Campo, Davinia; Acha-Salazar, Olga; Novo-Robledo, Francisco; Oterino, Agustín

2016-03-01

After an ischaemic stroke, to reduce LDL cholesterol (LDLc) levels decreases the risk of recurrence. The risk of recurrence is lower with more intense reductions in LDLc levels. To evaluate the efficacy and security of atorvastatin 40 mg plus ezetimibe 10 mg after ischaemic stroke or transient ischaemic attack (TIA). We retrospectively evaluated stroke or TIA patients admitted to our hospital who received atorvastatin 40 mg plus ezetimibe 10 mg (n = 34) or atorvastatin 80 mg (n = 52) at discharge. We analyzed changes in lipid parameters and established as a primary outcome LDLc <= 70 mg/dL and/or reduction in LDLc >= 50%. Furthermore, safety parameters were assessed. Predictors associated with primary outcome achievement were treatment with atorvastatin 40 mg plus ezetimibe 10 mg (odds ratio: 11.94; 95% CI: 2.82-50.64; p = 0.001) and male (odds ratio: 4.76; 95% CI: 1.35-16.67; p = 0.02). Treatment with atorvastatin 40 mg plus ezetimibe 10 mg achieved significantly greater reductions in LDLc (p < 0.001), total cholesterol (p < 0.001) and non-HDLc (p < 0.001). Both treatments were safe and well tolerated, with a low number of secondary effects. Compared with atorvastatin 80 mg, atorvastatin 40 mg plus ezetimibe 10 mg increases the likelihood of achieving LDLc goals after ischaemic stroke or transient ischaemic attack. Both treatments were safe and well tolerated.

Formation of Al3Ti/Mg composite by powder metallurgy of Mg-Al-Ti system.

PubMed

Yang, Zi R; Qi Wang, Shu; Cui, Xiang H; Zhao, Yu T; Gao, Ming J; Wei, Min X

2008-07-01

An in situ titanium trialuminide (Al 3 Ti)-particle-reinforced magnesium matrix composite has been successfully fabricated by the powder metallurgy of a Mg-Al-Ti system. The reaction processes and formation mechanism for synthesizing the composite were studied by differential scanning calorimetry (DSC), x-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). Al 3 Ti particles are found to be synthesized in situ in the Mg alloy matrix. During the reaction sintering of the Mg-Al-Ti system, Al 3 Ti particles are formed through the reaction of liquid Al with as-dissolved Ti around the Ti particles. The formed intermetallic particles accumulate at the original sites of the Ti particles. As sintering time increases, the accumulated intermetallic particles disperse and reach a relatively homogeneous distribution in the matrix. It is found that the reaction process of the Mg-Al-Ti system is almost the same as that of the Al-Ti system. Mg also acts as a catalytic agent and a diluent in the reactions and shifts the reactions of Al and Ti to lower temperatures. An additional amount of Al is required for eliminating residual Ti and solid-solution strengthening of the Mg matrix.

Effect of Mg on the Microstructure and Corrosion Resistance of the Continuously Hot-Dip Galvanizing Zn-Mg Coating

PubMed Central

Dong, Anping; Li, Baoping; Lu, Yanling; Zhu, Guoliang; Xing, Hui; Shu, Da; Sun, Baode; Wang, Jun

2017-01-01

The microstructure of continuously hot-dip galvanizing Zn-Mg coating was investigated in order to obtain the mechanism of the effects of Mg on the corrosion resistance. In this paper, the vertical section of the Zn-0.20 wt % Al-Mg ternary phase diagram near the Al-low corner was calculated. The results indicates that the phase composition of the Zn-0.20 wt % Al-Mg ternary phase diagram near the Al-low corner is the same as Zn-Mg binary phase diagram, suggesting Al in the Zn-Mg (ZM) coatings mainly concentrates on the interfacial layer between the coating and steel substrate. The microstructure of continuously hot-dip galvanizing ZM coatings with 0.20 wt % Al containing 1.0–3.0 wt % Mg was investigated using tunneling electron microscopy (TEM). The morphology of Zn in the coating changes from bulk to strip and finally to mesh-like, and the MgZn2 changes from rod-like to mesh-like with the Mg content increasing. Al in the ZM coatings mainly segregates at the Fe2Al5 inhibition layer and the Mg added to the Zn bath makes this inhibition layer thinner and uneven. Compared to GI coating, the time of the first red rust appears increases by more than two-fold and expansion rate of red rust reduces by more than four-fold in terms of salt spray experiment. The ZM coating containing 2.0 wt % Mg has the best corrosion resistance. The enhanced corrosion resistance of ZM coatings mainly depends on different corrosion products. PMID:28829393

Effect of Mg on the Microstructure and Corrosion Resistance of the Continuously Hot-Dip Galvanizing Zn-Mg Coating.

PubMed

Dong, Anping; Li, Baoping; Lu, Yanling; Zhu, Guoliang; Xing, Hui; Shu, Da; Sun, Baode; Wang, Jun

2017-08-22

The microstructure of continuously hot-dip galvanizing Zn-Mg coating was investigated in order to obtain the mechanism of the effects of Mg on the corrosion resistance. In this paper, the vertical section of the Zn-0.20 wt % Al-Mg ternary phase diagram near the Al-low corner was calculated. The results indicates that the phase composition of the Zn-0.20 wt % Al-Mg ternary phase diagram near the Al-low corner is the same as Zn-Mg binary phase diagram, suggesting Al in the Zn-Mg (ZM) coatings mainly concentrates on the interfacial layer between the coating and steel substrate. The microstructure of continuously hot-dip galvanizing ZM coatings with 0.20 wt % Al containing 1.0-3.0 wt % Mg was investigated using tunneling electron microscopy (TEM). The morphology of Zn in the coating changes from bulk to strip and finally to mesh-like, and the MgZn₂ changes from rod-like to mesh-like with the Mg content increasing. Al in the ZM coatings mainly segregates at the Fe₂Al₅ inhibition layer and the Mg added to the Zn bath makes this inhibition layer thinner and uneven. Compared to GI coating, the time of the first red rust appears increases by more than two-fold and expansion rate of red rust reduces by more than four-fold in terms of salt spray experiment. The ZM coating containing 2.0 wt % Mg has the best corrosion resistance. The enhanced corrosion resistance of ZM coatings mainly depends on different corrosion products.

Spin injection into silicon in three-terminal vertical and four-terminal lateral devices with Fe/Mg/MgO/Si tunnel junctions having an ultrathin Mg insertion layer

NASA Astrophysics Data System (ADS)

Sato, Shoichi; Nakane, Ryosho; Hada, Takato; Tanaka, Masaaki

2017-12-01

We demonstrate that the spin injection/extraction efficiency is enhanced by an ultrathin Mg insertion layer (⩽2 nm) in Fe /Mg /MgO /n+-Si tunnel junctions. In diode-type vertical three-terminal devices fabricated on a Si substrate, we observe the narrower three-terminal Hanle (N-3TH) signals indicating true spin injection into Si and estimate the spin polarization in Si to be 16% when the thickness of the Mg insertion layer is 1 nm, whereas no N-3TH signal is observed without the Mg insertion. This means that the spin injection/extraction efficiency is enhanced by suppressing the formation of a magnetically dead layer at the Fe/MgO interface. We also observe clear spin transport signals, such as nonlocal Hanle signals and spin-valve signals, in a lateral four-terminal device with the same Fe /Mg /MgO /n+-Si tunnel junctions fabricated on a Si-on-insulator substrate. It is found that both the intensity and linewidth of the spin signals are affected by the geometrical effects (device geometry and size). We have derived analytical functions taking into account the device structures, including channel thickness and electrode size, and estimated important parameters: spin lifetime and spin polarization. Our analytical functions explain the experimental results very well. Our study shows the importance of suppressing a magnetically dead layer and provides a unified understanding of spin injection/detection signals in different device geometries.

Knowledge and practice of prevention of mother-to-child transmission of HIV among traditional birth attendants in Lagos State, Nigeria.

PubMed

Balogun, Mobolanle; Odeyemi, Kofo

2010-04-29

Traditional birth attendants (TBAs) assist most deliveries in Nigeria. Knowing and understanding all issues surrounding HIV/AIDS and Prevention of Mother-To-Child Transmission of HIV (PMTCT) can help them to protect themselves and others. This study aimed to assess the knowledge and practice of PMTCT amongst TBAs in Lagos, Nigeria. This was a cross-sectional survey. Multistage sampling method was used to select 108 registered TBAs in 2 local governments areas who were interviewed using a pre-tested questionnaire. All the respondents were aware of HIV but their awareness of PMTCT specifically was not as high. Only 8.3% of the respondents had good level of knowledge about HIV and PMTCT and up to 13% of them claimed to be able to cure HIV using native remedies. The practices of HIV counseling of patients and referral of patients for HIV testing were low and higher levels of knowledge positively influenced these practices significantly (p < 0.05). They were also deficient in certain measures to prevent infection of patients and themselves. Most of the TBAs did not have adequate knowledge and practice of PMTCT illustrating the need for periodic PMTCT training for TBAs.

[Y/Mg] stellar dating calibration

NASA Astrophysics Data System (ADS)

Titarenko, A.; Recio-Blanco, A.; de Laverny, P.; Hayden, M.; Guiglion, G.; Worley, C.

2018-04-01

Gaia DR1 has opened a new era of stellar age dating, that is crucial for many astrophysical objectives. In addition, the Gaia based isochrone fitting ages can be compared to other chemical clocks like the [Y/Mg] one (Nissen et al. 2015). In our work we have used ESO archived data of the AMBRE project (de Laverny et al. 2013) for UVES spectra, in order to evaluate the age [Y/Mg] abundance correlation for turn off stars. 310 turn off stars of the UVES-archive (setups 564 and 580) are included in the TGAS database. Isochrone fitting ages were derived. We have applied the GAUGUIN procedure for those stars to derive the Mg and the Y abundances. As the result we present the [Y/Mg] vs stellar age dependence for ~40 TO-stars.

Fiber Laser Welding-Brazing Characteristics of Dissimilar Metals AZ31B Mg Alloys to Copper with Mg-Based Filler

NASA Astrophysics Data System (ADS)

Zhao, Xiaoye; Tan, Caiwang; Meng, Shenghao; Chen, Bo; Song, Xiaoguo; Li, Liqun; Feng, Jicai

2018-03-01

Fiber laser welding-brazing of 1-mm-thick AZ31B Mg alloys to 1.5-mm-thick copper (T2) with Mg-based filler was performed in a lap configuration. The weld appearance, interfacial microstructure and mechanical properties were investigated with different heat inputs. The results indicated that processing windows for optimizing appropriate welding parameters were relatively narrow in this case. Visually acceptable joints with certain strength were achieved at appropriate welding parameters. The maximum tensile-shear fracture load of laser-welded-brazed Mg/Cu joint could reach 1730 N at the laser power of 1200 W, representing 64.1% joint efficiency relative to AZ31Mg base metal. The eutectic structure (α-Mg + Mg2Cu) and Mg-Cu intermetallic compound was observed at the Mg/Cu interface, and Mg-Al-Cu ternary intermetallic compound were identified between intermetallics and eutectic structure at high heat input. All the joints fractured at the Mg-Cu interface. However, the fracture mode was found to differ. For laser power of 1200 W, the surface was characterized by tearing edge, while that with poor joint strength was almost dominated by smooth surface or flat tear pattern.

Mg isotope fractionation during microbe-mineral interactions

NASA Astrophysics Data System (ADS)

Kim, Insu; Ryu, Jong-sik; Lee, Kwang-sik; Lee, Dongho

2014-05-01

Magnesium is involved in various biogeochemical processes important to the global climate change over geological time-scale. Mg isotopes allow us to directly trace the Mg cycle in the Earth's surface but the factors controlling Mg isotopic compositions have not fully understood yet. Here, we conducted a batch experiment using two bacterial species (Shewanella putrefaciens and Burkholderia fungorum) and three major Mg-bearing minerals (biotite, dolomite and hornblende). All elemental concentrations increased by 336 h and then reached to steady-state values, of which Mg concentrations varied depending on minerals and bacterial species. This result indicates that the mineral dissolution is affect by the presence of microbes, which either provide organic acids or attach onto mineral surface. The Mg isotopic compositions of initial minerals biotite, dolomite and hornblende are -0.35o of biotite, -0.99o of dolomite, and -0.24o of hornblende, in δ26Mg. Similarly, δ26Mg values increased by 336 h and reached to steady-state values, which also varied with minerals and microbes. During dissolution of three minerals, the light isotope of Mg is preferentially incorporated into the dissolved phases and then the dissolved δ26Mg values become consistent with those of minerals with the time.

K{sub 2}Mg{sub 5-x}Sn{sub 3} and K{sub 3}Mg{sub 18}Tt{sub 11} (Tt=Sn, pb) with two types of Mg-Sn/Pb frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lei, Xiao-Wu, E-mail: xwlei10@163.co

2011-04-15

K{sub 2}Mg{sub 5-x}Sn{sub 3} (x=0.28) and K{sub 3}Mg{sub 18}Tt{sub 11} (Tt=Sn, Pb) have been synthesized by reacting the mixture of the corresponding pure elements at high temperature, and structurally characterized by single-crystal X-ray diffraction studies. K{sub 2}Mg{sub 5-x}Sn{sub 3} (x=0.28) is isostructural with Ni{sub 7-x}SbQ{sub 2} (Q=Se, Te) series and features 2D corrugated [Mg{sub 5-x}Sn{sub 3}] layers that are separated by K{sup +} cations. The structure of K{sub 3}Mg{sub 18}Tt{sub 11} (Tt=Sn, Pb) is closely related to the Ho{sub 2}Rh{sub 12}As{sub 7} structural type and features 3D [Mg{sub 18}Tt{sub 11}] framework composed of 1D [Mg{sub 18}Tt{sub 11}] columns that aremore » interconnected via Mg-Tt bonds, forming 1D hexagonal tunnels occupied by the K+ cations. Electronic structure calculations indicate that Mg atoms can function as either electron donor or as a participator in the network along with Tt atoms. Magnetic property measurements and band structure calculations indicate that these compounds are metallic. -- Graphical abstract: Two new K-Mg-Tt phases, K{sub 2}Mg{sub 5-x}Sn{sub 3} (x=0.28) and K{sub 3}Mg{sub 18}Tt{sub 11} (Tt=Sn, Pb), have been synthesized and structurally characterized. K{sub 2}Mg{sub 5-x}Sn{sub 3} is isostructural with Ni{sub 7-x}SbQ{sub 2} (Q=Se, Te) and features a 2D corrugated [Mg{sub 5}Sn{sub 3}] layer that is separated by K{sup +} cations, and K{sub 3}Mg{sub 18}Tt{sub 11} (Tt=Sn, Pb) is closely related to the Ho{sub 2}Rh{sub 12}As{sub 7} structure type and features a 3D [Mg{sub 18}Tt{sub 11}] network with 1D hexagonal tunnels along the c-axis occupied by K{sup +} cations. Display Omitted Research highlights: Two new polar intermetallics, K{sub 2}Mg{sub 5-x}Sn{sub 3} (x=0.28) and K{sub 3}Mg{sub 18}Tt{sub 11} (Tt=Sn, Pb). Electronic structure calculations were performed by both TB-LMTO and EHTB methods. Mg atom can function as either electron donor or participator in the network.« less

Structure and lattice dynamics of the wide band gap semiconductors MgSiN2 and MgGeN2

NASA Astrophysics Data System (ADS)

Râsander, M.; Quirk, J. B.; Wang, T.; Mathew, S.; Davies, R.; Palgrave, R. G.; Moram, M. A.

2017-08-01

We have determined the structural and lattice dynamical properties of the orthorhombic, wide band gap semiconductors MgSiN2 and MgGeN2 using density functional theory. In addition, we present the structural properties and Raman spectra of MgSiN2 powder. The structural properties and lattice dynamics of the orthorhombic systems are compared to those of wurtzite AlN. We find clear differences in the lattice dynamics between MgSiN2, MgGeN2 and AlN, for example, we find that the highest phonon frequency in MgSiN2 is about 100 cm-1 higher than the highest frequency in AlN, and that MgGeN2 is much softer. We also provide the Born effective charge tensors and dielectric tensors of MgSiN2, MgGeN2 and AlN. Phonon related thermodynamic properties, such as the heat capacity and the entropy, have also been evaluated and are found to be in very good agreement with available experimental results.

A randomized controlled clinical trial of levofloxacin 750 mg versus 500 mg intravenous infusion in the treatment of community-acquired pneumonia.

PubMed

Zhao, Xu; Wu, Ju-Fang; Xiu, Qing-Yu; Wang, Chen; Zhang, De-Ping; Huang, Jian-An; Xie, Can-Mao; Sun, Sheng-Hua; Lv, Xiao-Ju; Si, Bin; Xiao, Zu-Ke; Zhang, Ying-Yuan

2014-10-01

The objective of this study was to compare the efficacy and safety of levofloxacin 750 mg for 5 days versus 500 mg for 7-14 days intravenous (IV) in the treatment of community-acquired pneumonia (CAP). This clinical trial was the first of its kind conducted in Chinese people and also in Asian population. A total of 241 were enrolled and randomized to 750 mg group (n = 121) or 500 mg (n = 120) group from 10 study centers. The median treatment duration was 5.0 days in 750 mg and 9.0 days in 500 mg group. The median total dose was 3750 mg in 750 mg and 4500 mg in 500 mg group. The bacterial eradication rate was 100% in both groups. The overall efficacy rate in 750 mg group was 86.2% (94/109), and 84.7% (94/111), in 500 mg group of full analysis set visit 4, 95% confidence interval of 1.6% (-7.8-10.9%); the statistical results showed that 750 mg group was non-inferior to 500 mg group. The most common clinical adverse drug reactions were injection site adverse reactions in both 750 mg group and 500 mg group; the other common adverse drug reactions were insomnia, nausea, skin rash, etc. The most common drug-related laboratory abnormalities were neutrophil percentage decreased, decreased white blood cell count, alanine aminotransferase, and aspartate aminotransferase elevation in both 750 mg group and 500 mg group. Most of adverse drug reactions were mild in severity and well-tolerated. In summary, the regimen of levofloxacin 750 mg IV for 5 days was at least as effective and well tolerated as 500 mg IV for 7-14 days for the treatment of CAP. Copyright © 2014. Published by Elsevier Inc.

Defect-Tolerant Diffusion Channels for Mg 2+ Ions in Ribbon-Type Borates: Structural Insights into Potential Battery Cathodes MgVBO 4 and Mg x Fe 2–xB 2O 5

DOE PAGES

Bo, Shou-Hang; Grey, Clare P.; Khalifah, Peter G.

2015-06-10

The reversible room temperature intercalation of Mg 2+ ions is difficult to achieve, but may offer substantial advantages in the design of next-generation batteries if this electrochemical process can be successfully realized. Two types of quadruple ribbon-type transition metal borates (Mg xFe 2-xB 2O 5 and MgVBO 4) with high theoretical capacities (186 mAh/g and 360 mAh/g) have been synthesized and structurally characterized through the combined Rietveld refinement of synchrotron and time-of-flight neutron diffraction data. Neither MgVBO 4 nor Mg xFe 2-xB 2O 5 can be chemically oxidized at room temperature, though Mg can be dynamically removed from themore » latter phase at elevated temperatures (approximately 200 - 500 °C). Findings show that Mg diffusion in the Mg xFe 2-xB 2O 5 structure is more facile for the inner two octahedral sites than for the two outer octahedral sites in the ribbons, a result supported by both the refined site occupancies after Mg removal and by bond valence sum difference map calculations of diffusion paths in the pristine material. Mg diffusion in this pyroborate Mg xFe 2-xB 2O 5 framework is also found to be tolerant to the presence of Mg/Fe disorder since Mg ions can diffuse through interstitial channels which bypass Fe-containing sites.« less

A Transient Rise in Free Mg2+ Ions Released from ATP-Mg Hydrolysis Contributes to Mitotic Chromosome Condensation.

PubMed

Maeshima, Kazuhiro; Matsuda, Tomoki; Shindo, Yutaka; Imamura, Hiromi; Tamura, Sachiko; Imai, Ryosuke; Kawakami, Syoji; Nagashima, Ryosuke; Soga, Tomoyoshi; Noji, Hiroyuki; Oka, Kotaro; Nagai, Takeharu

2018-02-05

For cell division, negatively charged chromatin, in which nucleosome fibers (10 nm fibers) are irregularly folded [1-5], must be condensed into chromosomes and segregated. While condensin and other proteins are critical for organizing chromatin into the appropriate chromosome shape [6-17], free divalent cations such as Mg 2+ and Ca 2+ , which condense chromatin or chromosomes in vitro [18-28], have long been considered important, especially for local condensation, because the nucleosome fiber has a net negative charge and is by itself stretched like "beads on a string" by electrostatic repulsion. For further folding, other positively charged factors are required to decrease the charge and repulsion [29]. However, technical limitations to measure intracellular free divalent cations, but not total cations [30], especially Mg 2+ , have prevented us from elucidating their function. Here, we developed a Förster resonance energy transfer (FRET)-based Mg 2+ indicator that monitors free Mg 2+ dynamics throughout the cell cycle. By combining this indicator with Ca 2+ [31] and adenosine triphosphate (ATP) [32] indicators, we demonstrate that the levels of free Mg 2+ , but not Ca 2+ , increase during mitosis. The Mg 2+ increase is coupled with a decrease in ATP, which is normally bound to Mg 2+ in the cell [33]. ATP inhibited Mg 2+ -dependent chromatin condensation in vitro. Chelating Mg 2+ induced mitotic cell arrest and chromosome decondensation, while ATP reduction had the opposite effect. Our results suggest that ATP-bound Mg 2+ is released by ATP hydrolysis and contributes to mitotic chromosome condensation with increased rigidity, suggesting a novel regulatory mechanism for higher-order chromatin organization by the intracellular Mg 2+ -ATP balance. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Comparative study on the structure and electrochemical hydriding properties of MgTi, Mg 0.5Ni 0.5Ti and MgTi 0.5Ni 0.5 alloys prepared by high energy ball milling

NASA Astrophysics Data System (ADS)

Rousselot, Steeve; Guay, Daniel; Roué, Lionel

MgTi, Mg 0.5Ni 0.5Ti and MgTi 0.5Ni 0.5 alloys doped with 10 wt.% Pd were prepared by high energy ball milling and evaluated as hydrogen storage electrodes for Ni-MH batteries. X-ray diffraction analyses indicated that the Mg 0.5Ni 0.5Ti and MgTi 0.5Ni 0.5 alloys could be monophased or composed of a nanoscale mixture of MgTi + NiTi and MgTi + MgNi phases, respectively. Their hydrogen storage characteristics were investigated electrochemically in KOH electrolyte. No activation step was observed during the cycling of the Mg-Ti-Ni electrodes in contrast to that observed with the MgTi electrode. The highest hydrogen discharge capacity was obtained with the MgTi 0.5Ni 0.5 electrode (536 mAh g -1) compared to 401 and 475 mAh g -1 for the Mg 0.5Ni 0.5Ti and MgTi electrodes, respectively. The ternary Mg-Ti-Ni alloys showed a better cycle life with an average capacity decay rate per cycle lower than 1.5% compared to ∼7% for the binary MgTi electrode. The Mg-Ni-Ti electrodes also displayed a much higher discharge rate capability than the binary MgTi electrode, especially with the Mg 0.5Ni 0.5Ti electrode. The origin of this was established on the basis of the anodic polarization curves, where a substantial decrease of the concentration overpotential (reflecting a higher hydrogen diffusivity) was observed for the Mg 0.5Ni 0.5Ti electrode.

Density functional theory (DFT) study on the hydrolysis behavior of degradable Mg/Mg alloys for biomedical applications

NASA Astrophysics Data System (ADS)

Nezafati, Marjan

Magnesium-based (Mg and/or Mg alloys) materials possess many advantageous physicochemical/biological characteristics such as good biocompatibility and similarity of the mechanical properties to the human bone tissue, which renders this material a promising candidate for the biomedical and implant applications. One of the most attractive features of Mg-based materials is the degradability in the physiological environment. With the burst of research on the biodegradable materials for the healthcare device applications, Mg and its alloys attracted a strong attention in the bioengineering field in recent years. However, the major limitation of applying Mg-based materials to biomedical applications is the fast degradation/corrosion rate with regards to the healing process time-span. In the present thesis, an atomistic model employing the density-functional theory (DFT) has been developed to study the hydrolysis process by understanding the influences of commonly used alloying elements (zinc (Zn), calcium (Ca), aluminum (Al), and yttrium (Y)) and the crystallographic orientation of the dissolution surfaces (basal (0001), prism (1010), and pyramidal (1011) planes) on the corrosion behavior. These parameters are known to strongly impact the initial hydrolysis phenomena of Mg-based materials. To develop the atomistic computational model, we have implemented the Dmol3 software package in conjunction with PBE (Perdew, Burke and Ernzerhof) correlation energy functional in the GGA (generalized gradient approximation) scheme. Throughout the thesis, we performed three sets of calculations, i) surface energy, ii) dissolution potential, and iii) water adsorption computations, to examine the hydrolysis mechanism and the subsequent corrosion/degradation of Mg/Mg alloys. The total energy changes of various Mg-based systems in different conditions for these surface energies, dissolution behavior, and tendency of the system for adsorbing the water molecule were quantified. The results

Effect of organic ligands on Mg partitioning and Mg isotope fractionation during low-temperature precipitation of calcite

NASA Astrophysics Data System (ADS)

Mavromatis, Vasileios; Immenhauser, Adrian; Buhl, Dieter; Purgstaller, Bettina; Baldermann, Andre; Dietzel, Martin

2016-04-01

Calcite growth experiments have been performed at 25 oC and 1 bar pCO2 in the presence of aqueous Mg and six organic ligands in the concentration range from 10-5 to 10-3 M. These experiments were performed in order to quantify the effect of distinct organic ligands on the Mg partitioning and Mg stable isotope fractionation during its incorporation in calcite at similar growth rates normalized to total surface area. The organic ligands used in this study comprise of (i) acetate acid, (ii) citrate, (iii) glutamate, (iv) salicylate, (v) glycine and (vi) ethylenediaminetetraacetic acid (EDTA), containing carboxyl- and amino-groups. These fuctional groups are required for bacterial activity and growth as well as related to biotic and abiotic mineralization processes occurring in sedimentary and earliest diagenetic aquatic environments (e.g. soil, cave, lacustrine, marine). The results obtained in this study indicate that the presence of organic ligands promotes an increase in the partition coefficient of Mg in calcite (DMg = (Mg/Ca)calcite (Mg/Ca)fluid). This behaviour can be explained by the temporal formation of aqueous Mg-ligand complexes that are subsequently adsorbed on the calcite surfaces and thereby reducing the active growth sites of calcite. The increase of DMg values as a function of the supersaturation degree of calcite in the fluid phase can be described by the linear equation LogDMg =0.3694 (±0.0329)×SIcalcite - 1.9066 (±0.0147); R2=0.92 In contrast, the presence of organic ligands, with exception of citrate, does not significantly affect the Mg isotope fractionation factor between calcite and reactive fluid (Δ26Mgcalcite-fluid = -2.5 ±0.1). Citrate likely exhibits larger fractionation between the Mg-ligand complexes and free aqueous Mg2+, compared to the other organic ligands studied in this work, as evidenced by the smaller Δ26Mgcalcite-fluid values. These results indicate that in Earth's surface calcite precipitating environments that are

Effect of Cold Rolling on Age Hardening in Excess Mg-Type Al-Mg-Si Alloys Including Some Minor Elements

NASA Astrophysics Data System (ADS)

Ogawa, Yurie; Matsuda, Kenji; Kawabata, Tokimasa; Uetani, Yasuhiro; Ikeno, Susumu

It has been known that transition metals improve the mechanical property of Al-Mg-Si alloy. The thermo-mechanical treatment is also effective to improve the strength of Al-Mg-Si alloy. In this work, the aging behavior of deformed excess Mg-type Al-Mg-Si alloy including Ag,Cu,Pt was investigated by hardness test and TEM observation. The value of the maximum hardness increased and the aging time to the maximum hardness became shorter by increasing the amount of the deformation. The age-hardening ability (ΔHV) was decreased with increasing amount of the deformation. The effect of additional element on AHV was also similar to the result of the deformation described above. Comparing the value of the maximum hardness for the alloys aged at 423-523 K, the ex. Mg-Cu alloy was the highest, the ex. Mg-Ag alloy was middle, and the ex. Mg and ex. Mg-Pt alloys were the lowest because of total amounts of added elements.

A fundamental study on the [(μ-Cl)3Mg2(THF)6]+ dimer electrolytes for rechargeable Mg batteries†

PubMed Central

Cox, Jonathan T.; Hu, Dehong; Deng, Xuchu; Hu, Jianzhi; Hu, Mary Y.; Xiao, Jie; Shao, Yuyan; Tang, Keqi; Liu, Jun

2016-01-01

The long sought solvated [MgCl]+ species in the Mg-dimer electrolytes was characterized by soft mass spectrometry. The presented study provides an insightful understanding on the electrolyte chemistry of rechargeable Mg batteries. PMID:25562393

Biocompatibility Assessment of Novel Bioresorbable Alloys Mg-Zn-Se and Mg-Zn-Cu for Endovascular Applications: In- Vitro Studies.

PubMed

Persaud-Sharma, Dharam; Budiansky, Noah; McGoron, Anthony J

2013-01-01

Previous studies have shown that using biodegradable magnesium alloys such as Mg-Zn and Mg-Zn-Al possess the appropriate mechanical properties and biocompatibility to serve in a multitude of biological applications ranging from endovascular to orthopedic and fixation devices. The objective of this study was to evaluate the biocompatibility of novel as-cast magnesium alloys Mg-1Zn-1Cu wt.% and Mg-1Zn-1Se wt.% as potential implantable biomedical materials, and compare their biologically effective properties to a binary Mg-Zn alloy. The cytotoxicity of these experimental alloys was evaluated using a tetrazolium based- MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and a lactate dehydrogenase membrane integrity assay (LDH). The MTS assay was performed on extract solutions obtained from a 30-day period of alloy immersion and agitation in simulated body fluid to evaluate the major degradation products eluted from the alloy materials. Human foreskin fibroblast cell growth on the experimental magnesium alloys was evaluated for a 72 hour period, and cell death was quantified by measuring lactate dehydrogenase concentrations. Both Mg-Zn-Se and Mg-Zn-Cu alloys exhibit low cytotoxicity levels which are suitable for biomaterial applications. The Mg-Zn-Cu alloy was found to completely degrade within 72 hours, resulting in lower human foreskin fibroblast cell viability. The Mg-Zn-Se alloy was shown to be less cytotoxic than both the Mg-Zn-Cu and Mg-Zn alloys.

Biocompatibility Assessment of Novel Bioresorbable Alloys Mg-Zn-Se and Mg-Zn-Cu for Endovascular Applications: In- Vitro Studies

PubMed Central

Budiansky, Noah; McGoron, Anthony J.

2013-01-01

Previous studies have shown that using biodegradable magnesium alloys such as Mg-Zn and Mg-Zn-Al possess the appropriate mechanical properties and biocompatibility to serve in a multitude of biological applications ranging from endovascular to orthopedic and fixation devices. The objective of this study was to evaluate the biocompatibility of novel as-cast magnesium alloys Mg-1Zn-1Cu wt.% and Mg-1Zn-1Se wt.% as potential implantable biomedical materials, and compare their biologically effective properties to a binary Mg-Zn alloy. The cytotoxicity of these experimental alloys was evaluated using a tetrazolium based- MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and a lactate dehydrogenase membrane integrity assay (LDH). The MTS assay was performed on extract solutions obtained from a 30-day period of alloy immersion and agitation in simulated body fluid to evaluate the major degradation products eluted from the alloy materials. Human foreskin fibroblast cell growth on the experimental magnesium alloys was evaluated for a 72 hour period, and cell death was quantified by measuring lactate dehydrogenase concentrations. Both Mg-Zn-Se and Mg-Zn-Cu alloys exhibit low cytotoxicity levels which are suitable for biomaterial applications. The Mg-Zn-Cu alloy was found to completely degrade within 72 hours, resulting in lower human foreskin fibroblast cell viability. The Mg-Zn-Se alloy was shown to be less cytotoxic than both the Mg-Zn-Cu and Mg-Zn alloys. PMID:24058329

Effect of Mg content on the thermal stability and mechanical behaviour of PLLA/Mg composites processed by hot extrusion.

PubMed

Cifuentes, S C; Lieblich, M; López, F A; Benavente, R; González-Carrasco, J L

2017-03-01

In the field of bioabsorbable composites for biomedical applications, extrusion has been employed as a method to prepare homogeneous blends of polymeric matrices with bioactive ceramic fillers. In this work, the suitability of processing poly-l-lactic acid/Magnesium (PLLA/Mg) composites by hot extrusion has been assessed by a systematic characterization of PLLA/Mg composites containing different amounts of Mg particles up to 7wt%. The results show that extrusion causes a reduction of almost 20% in the viscosity average molecular weight of PLLA, which further decreases with increasing Mg content. Extrusion gave always rise to a homogeneous distribution of Mg particles within the PLLA matrix. This composite processing was not compromised by the degradation of the polymeric matrix because the processing temperature was always below the onset degradation temperature. In the processing conditions employed in the present work, degradation of the composite slightly increases as more Mg is added up to 5wt%, but is very high at 7wt%. This was also evident from the mechanical behaviour, so that Mg particles improved the stiffness and compression strength of neat PLLA until 5wt% of Mg content, which dropped drastically when the material had 7wt% of Mg. The filler strengthening factor decreases with the increment in Mg content. In order to obtain an optimised contribution of Mg particles, a balance between thermal degradation and mechanical resistance of PLLA must be achieved. Copyright © 2016 Elsevier B.V. All rights reserved.

Atomic simulation of mechanical behavior of Mg in a super-lattice of nanocrystalline Mg and amorphous Mg-Al alloy

NASA Astrophysics Data System (ADS)

Song, H. Y.; An, M. R.; Li, Y. L.; Deng, Q.

2014-12-01

The mechanical properties of a super-lattice architecture composed of nanocrystalline Mg and Mg-Al amorphous alloy are investigated using molecular dynamics simulation. The results indicate that deformation mechanism of nanocrystalline Mg is obviously affected by the amorphous boundary spacing and temperature. The strength of the material increases with the decrease of amorphous boundary spacing, presenting a Hall-Petch effect at both 10 K and 300 K. A stress platform and following stiffness softening, as well as a linear strengthening in the plastic stage, are observed when the amorphous boundary spacing below 8.792 nm at 10 K. The implying reason may be that the amorphous boundary acts as the dislocations emission and absorption source. However, the second stress peak is not observed for the models at 300 K. Instead, the flow stress in plastic stage is a nearly constant value. The simulation demonstrates the emergence of the new grain, accompanied by the deformation twins and stacking faults associated with the plastic behaviors at 300 K. The general conclusions derived from this work may provide a guideline for the design of high-performance hexagonal close-packed metals.

Effectiveness of barnidipine 10 or 20 mg plus losartan 50-mg combination versus losartan 100-mg monotherapy in patients with essential hypertension not controlled by losartan 50-mg monotherapy: A 12-week, multicenter, randomized, open-label, parallel-group study.

PubMed

Parati, Gianfranco; Giglio, Alessia; Lonati, Laura; Destro, Maurizio; Ricci, Alessandra Rossi; Cagnoni, Francesca; Pini, Claudio; Venco, Achille; Maresca, Andrea Maria; Monza, Michela; Grandi, Anna Maria; Omboni, Stefano

2010-07-01

Increasing the dose or adding a second antihypertensive agent are 2 possible therapeutic choices when blood pressure (BP) is poorly controlled with monotherapy. This study investigated the effectiveness and tolerability of barnidipine 10 or 20 mg added to losartan 50 mg versus losartan 100 mg alone in patients with mild to moderate essential hypertension whose BP was uncontrolled by losartan 50-mg monotherapy. This was a 12-week, multicenter, randomized, open-label, parallel-group study. Eligible patients (aged 30-74 years) had uncontrolled hypertension, defined as office sitting diastolic BP (DBP) > or =90 mm Hg and/or systolic BP (SBP) > or =140 mm Hg, and mean daytime DBP > or =85 mm Hg and/or SBP > or =135 mm Hg. All were being treated with losartan 50 mg at enrollment. After a 1-week run-in period while taking losartan 50 mg, patients were randomly assigned to 6 weeks of treatment with open-label barnidipine 10 mg plus losartan 50 mg or losartan 100-mg monotherapy. At the end of this period, patients with uncontrolled BP had barnidipine doubled to 20 mg and continued for an additional 6 weeks, whereas patients not achieving control on treatment with losartan 100 mg were discontinued. Office BP was measured at each visit, whereas 24-hour ambulatory BP monitoring (ABPM) was performed at randomization and at the final visit (ie, after 12 weeks of treatment, or at 6 weeks for patients not controlled on losartan 100 mg). The intent-to-treat population included all randomized patients who received at least one dose of study treatment and had valid ABPM recordings at baseline and the final visit. The primary end point was the change in daytime DBP between baseline and 12 weeks of treatment, compared between the combination treatment and monotherapy. Adverse events (AEs) were evaluated during each study visit. A total of 93 patients were enrolled (age range, 30-75 years; 60% [56/93] men). After the 1-week run-in period, 68 patients were randomly assigned to 6 weeks of

Incidence of deep vein thrombosis is increased with 30 mg twice daily dosing of enoxaparin compared with 40 mg daily.

PubMed

Riha, Gordon M; Van, Philbert Y; Differding, Jerome A; Schreiber, Martin A

2012-05-01

The purpose of this study was to analyze whether 2 standard dosing regimens of enoxaparin (30 mg twice daily vs 40 mg once daily) would result in different deep vein thrombosis (DVT) rates and anti-factor Xa activity (anti-Xa) in surgical patients. Patients who required enoxaparin for prophylaxis were followed prospectively. Demographics were recorded. Patients underwent standardized duplex screening. Peak anti-Xa levels were drawn on 4 consecutive days. Sixty-three patients were followed up (28 patients on 30 mg twice daily, 35 patients on 40 mg once daily). There was no significant difference in demographics between groups. Twenty-five percent of patients on 30 mg twice daily developed a DVT, whereas 2.9% of patients on 40 mg once daily developed a DVT. Patients on 30 mg twice daily had significantly lower anti-Xa levels. The incidence of DVT is increased in surgical patients who receive 30 mg twice daily dosing of enoxaparin compared with 40 mg daily. Dosing of 40 mg once daily results in significantly higher peak anti-Xa levels compared with 30 mg twice daily. Copyright © 2012 Elsevier Inc. All rights reserved.

Preparation and Bond Properties of Thermal Barrier Coatings on Mg Alloy with Sprayed Al or Diffused Mg-Al Intermetallic Interlayer

NASA Astrophysics Data System (ADS)

Fan, Xizhi; Wang, Ying; Zou, Binglin; Gu, Lijian; Huang, Wenzhi; Cao, Xueqiang

2014-02-01

Sprayed Al or diffused Mg-Al layer was designed as interlayer between the thermal barrier coatings (TBCs) and Mg alloy substrate. The effects of the interlayer on the bond properties of the coats were investigated. Al layers were prepared by arc spraying and atmospheric plasma spraying (APS), respectively. Mg-Al diffused layer was obtained after the heat treatment of the sprayed sample (Mg alloy with APS Al coat) at 400 °C. The results show that sprayed Al interlayer does not improve the bond stability of TBCs. The failure of the TBCs on Mg alloy with Al interlayer occurs mainly due to the low strength of Al layer. Mg-Al diffused layer improves corrosion resistance of substrate and the bond interface. The TBCs on Mg alloy with Mg-Al diffused interlayer shows better bond stability than the sample of which the TBCs is directly sprayed on Mg alloy substrate by APS.

Chlorophyll-a Photosynthesis and Mg Isotope Fractionation

NASA Astrophysics Data System (ADS)

Black, J.; Yin, Q.; Casey, B. H.

2006-12-01

Mg is the metal center of all the chlorophyll pigments and therefore at the center of the process of photosynthesis. Chlorophyll (Chl) is often used as a biomarker of photosynthesis and is an enormous contributor to the global carbon cycle. Biosynthetic processes fractionate isotopes of light elements and this led us to examine the isotopic composition of Mg in Chl, as another potential biomarker. Here we detail the Mg isotopic composition of Chl-a, extracted from cultures of Synechococcus elongatus, and the culture medium (Black et al., 2006). After Chl extraction, the Mg was liberated from Chl and purified on cation-exchange columns, with a final yield of 100 ± 5%. ^{26}Mg/^{24}Mg and ^{25}Mg/^{24}Mg, were measured relative to Cambridge 1 and DSM3 standards by a standard-sample-bracketing technique on an MC-ICP-MS (Nu Instruments Ltd). We have measured the average isotopic fractionation of Mg from six samples of Chl-a from early growth phase and 4 samples from late growth phase, 9 samples of the culture medium and the Cambridge 1 Std, all relative to the DSM3 Std. We demonstrate for the first time that there is a clearly resolved depletion in the heavy isotopes of Mg in Chl-a relative to the culture medium (Δ^{26}Mg =-0.61‰; Δ^{25}Mg =-0.30‰). The heavy isotope depletion observed may be caused by chelation effects during the biosynthesis of Chl-a. We are now evaluating two hypotheses about the cause of the fractionation. One hypothesis is that the insertion step induces a fractionation via the Mg- chelatase enzyme. The second is that transport into the cell, such as via an ion channel, causes the fractionation. In either case, no difference between Chl-a and Chl-b is anticipated. Experiments and field studies are underway to examine these ideas. References Black, J., Yin, Q.-Z., Casey, W.H., 2006. Geochim. Cosmochim. Acta, 70, 4072-4079.

The in vitro biocompatibility and macrophage phagocytosis of Mg17Al12 phase in Mg-Al-Zn alloys.

PubMed

Liu, Chen; He, Peng; Wan, Peng; Li, Mei; Wang, Kehong; Tan, Lili; Zhang, Yu; Yang, Ke

2015-07-01

Mg alloys are gaining interest for applications as biodegradable medical implant, including Mg-Al-Zn series alloys with good combination of mechanical properties and reasonable corrosion resistance. However, whether the existence of second phase particles in the alloys exerts influence on the biocompatibility is still not clear. A deeper understanding of how the particles regulate specific biological responses is becoming a crucial requirement for their subsequent biomedical application. In this work, the in vitro biocompatibility of Mg17Al12 as a common second phase in biodegradable Mg-Al-Zn alloys was investigated via hemolysis, cytotoxicity, cell proliferation, and cell adhesion tests. Moreover, osteogenic differentiation was evaluated by the extracellular matrix mineralization assay. The Mg17Al12 particles were also prepared to simulate the real situation of second phase in the in vivo environment in order to estimate the cellular response in macrophages to the Mg17Al12 particles. The experimental results indicated that no hemolysis was found and an excellent cytocompatibility was also proved for the Mg17Al12 second phase when co-cultured with L929 cells, MC3T3-E1 cells and BMSCs. Macrophage phagocytosis co-culture test revealed that Mg17Al12 particles exerted no harmful effect on RAW264.7 macrophages and could be phagocytized by the RAW264.7 cells. Furthermore, the possible inflammatory reaction and metabolic way for Mg17Al12 phase were also discussed in detail. © 2014 Wiley Periodicals, Inc.

Maintenance treatment of duodenal ulceration: ranitidine 300 mg at night is better than 150 mg in cigarette smokers.

PubMed Central

Lee, F I; Hardman, M; Jaderberg, M E

1991-01-01

Two hundred patients received either ranitidine 150 mg or 300 mg at night for 18 months to prevent duodenal ulcer relapse. Recurrence rates were lower in patients receiving the higher dose of ranitidine (3.1% v 9.7%, p = 0.78; 6.5% v 16.7%, p = 0.037; and 8.9% v 17.0%, p = 0.121 at six, 12, and 18 months respectively). In patients receiving ranitidine 150 mg, recurrences were significantly more common in smokers than non-smokers after 12 and 18 months, while in patients receiving ranitidine 300 mg recurrence rates were similar in smokers and non-smokers. Ranitidine 300 mg at night abolishes the adverse effect of smoking observed during maintenance treatment with ranitidine 150 mg at night and may therefore be an appropriate maintenance dose for smokers who relapse during standard dose maintenance treatment. PMID:1864532

Surface treatments for controlling corrosion rate of biodegradable Mg and Mg-based alloy implants

PubMed Central

Uddin, M S; Hall, Colin; Murphy, Peter

2015-01-01

Due to their excellent biodegradability characteristics, Mg and Mg-based alloys have become an emerging material in biomedical implants, notably for repair of bone as well as coronary arterial stents. However, the main problem with Mg-based alloys is their rapid corrosion in aggressive environments such as human bodily fluids. Previously, many approaches such as control of alloying materials, composition and surface treatments, have been attempted to regulate the corrosion rate. This article presents a comprehensive review of recent research focusing on surface treatment techniques utilised to control the corrosion rate and surface integrity of Mg-based alloys in both in vitro and in vivo environments. Surface treatments generally involve the controlled deposition of thin film coatings using various coating processes, and mechanical surfacing such as machining, deep rolling or low plasticity burnishing. The aim is to either make a protective thin layer of a material or to change the micro-structure and mechanical properties at the surface and sub-surface levels, which will prevent rapid corrosion and thus delay the degradation of the alloys. We have organised the review of past works on coatings by categorising the coatings into two classes—conversion and deposition coatings—while works on mechanical treatments are reviewed based on the tool-based processes which affect the sub-surface microstructure and mechanical properties of the material. Various types of coatings and their processing techniques under two classes of coating and mechanical treatment approaches have been analysed and discussed to investigate their impact on the corrosion performance, biomechanical integrity, biocompatibility and cell viability. Potential challenges and future directions in designing and developing the improved biodegradable Mg/Mg-based alloy implants were addressed and discussed. The literature reveals that no solutions are yet complete and hence new and innovative approaches

Electrochemical Codeposition of Al-Li-Mg Alloys at Solid Aluminum Electrode from LiCl-KCl-MgCl2 Molten Salt System

NASA Astrophysics Data System (ADS)

Ye, Ke; Zhang, Mi Lin; Chen, Ye; Han, Wei; de Yan, Yong; Cao, Peng

2010-06-01

The electrochemical codeposition of Mg and Li at an aluminium electrode in LiCl-KCl (50:50 wt pct) melts containing different concentrations of MgCl2 at 893 K (620 °C) to form Al-Li-Mg alloys was investigated. Cyclic voltammograms showed that the potential of Li metal deposition at an Al electrode, before the addition of MgCl2, is more positive than that of Li metal deposition at an Mo electrode, which indicated the formation of an Al-Li alloy. The underpotential deposition of magnesium at an aluminium electrode leads to the formation of Al-Mg alloys, and the succeeding underpotential deposition of lithium on predeposited Al-Mg alloys leads to the formation of Al-Li-Mg alloys. Chronopotentiometric measurements indicated that the codeposition of Mg and Li occurs at current densities lower than -0.668 A cm-2 in LiCl-KCl-MgCl2 (8 wt pct) melts at an aluminium electrode. The chronoamperometric studies indicated that the onset potential for the codeposition of Mg and Li is -2.000 V, and the codeposition of Mg and Li at an aluminium electrode is formed into Al-Li-Mg alloys when the applied potentials are more negative than -2.000 V. X-ray diffraction and inductively coupled plasma analysis indicated that Al-Li-Mg alloys with different lithium and magnesium contents were prepared via potentiostatic and galvanostatic electrolysis. The microstructure of typical dual phases of the Al-Li-Mg alloy was characterized by an optical microscope and by scanning electron microscopy. The analysis of energy dispersive spectrometry showed that the elements of Al and Mg distribute homogeneously in the Al-Li-Mg alloy. The lithium and magnesium contents of Al-Li-Mg alloys can be controlled by MgCl2 concentrations and by electrolytic parameters.

Client perception of service quality at the outpatient clinics of a General hospital in Lagos, Nigeria.

PubMed

Ogunnowo, Babatunde Enitan; Olufunlayo, Tolulope Florence; Sule, Salami Suberu

2015-01-01

Service quality assessments have assumed increasing importance in the last two decades. They are useful in identifying gaps in services been provided with the ultimate aim of guaranteeing quality assurance. The objective of this study was to assess the client perception of service quality at the outpatient clinics of Randle General hospital, Lagos. A descriptive cross sectional study was conducted from March to May 2013. A multistage sampling technique was used to select respondents and data was collected with the aid of modified SERVQUAL questionnaires. The data was analysed with aid of EPI-INFO 2002 and statistical significance was set at a P value 0.05 for statistical significance. Total of 400 respondents were interviewed. The mean age was 40 years with a standard deviation of 15.2 yrs. The highest mean score of 4.35 out of a possible maximum of 5 was recorded in assurance domain while the lowest mean score of 4.00 was recorded in the responsiveness domain. The overall mean score of all the domains was 4.20 with standard deviation of 0.51. Overall majority (80.8%) of respondents rated the overall service quality as good/ very good. After linear regression, the assurance domain was the most important predictor of the overall perceived service quality (p< 0.001). The overall perceived service quality was good. The major deficiencies were in the responsiveness domain and especially the waiting time. The hospital management should implement measures to improve the responsiveness of services by ensuring prompt delivery of services.

Effects of various Mg/Si ratios on microstructure and performance property of Al-Mg-Si alloy cables

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Xuexuan

2016-09-15

High quality AA6101 aluminum cables are critical to electrical industry to meet the energy consumption requests. In the present work, the influence of Mg/Si ratios on the electrical conductivity and mechanical properties of AA6101 aluminum alloy was investigated. Wheatstone Bridge method and tensile test were employed to characterize the mechanical properties. X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were used to understand the morphology of the precipitation and the mechanism of age hardening. It is found that excessive Si benefits high strength and high conductivity while excessive Mg plays a negative role in the strengthmore » and the conductivity of AA6101 cables. Excessive Si elements promote both the precipitating rate and quantity of β″ phase therefore increase the tensile strength. Excessive Si elements also help with decreasing the lattice distortion, which contributes to the enhancement of the conductivity. Excessive Mg elements lead to more dissolved Mg after aging treatment, therefore increase lattice distortion of the matrix and promote the deposit of coarse Mg-enriched secondary phase. - Highlights: •A new available method to improve the mechanical and electrical properties of Al-Mg-Si alloy •Investigation on the role of various Mg/Si ratios in the changes of comprehensive performances •Discussions on the morphology of the precipitation phases and the mechanism of hardening.« less

Relative bioavailability of ondansetron 8-mg oral tablets versus two extemporaneous 16-mg suppositories: formulation and gender differences.

PubMed

Jann, M W; ZumBrunnen, T L; Tenjarla, S N; Ward, E S; Weidler, D J

1998-01-01

To compare the relative bioavailability of two 16-mg extemporaneously prepared suppository formulations with that of an 8-mg commercially available oral tablet. Prospective, crossover bioavailability study. Inpatient clinical research center. Sixteen young, nonsmoking, healthy volunteers. Blood samples were obtained 24 and 48 hours after administration of an 8-mg oral ondansetron tablet and 16-mg suppository, respectively. Two 16-mg suppository formulations were compounded using commercially available Fattibase and Polybase. Ondansetron was well absorbed by both routes of administration. The following pharmacokinetic parameters (mean+/-SEM) were obtained for the 8-mg tablet, 16-mg Fattibase suppository, and 16-mg Polybase suppository, respectively: area under the curve (AUC) in men 154.2+/-21.77, 253.4+/-72.3, 304.8+/-62.2 ng x hr/ml; AUC in women 353.6+/-32.7, 561.6+/-103.6, and 768.7+/-117.9 ng x hr/ml; maximum concentration (Cmax) in men 45.5+/-7.0, 40.6+/-10.4, and 51.2+/-6.7 ng/ml; Cmax in women 51.4+/-.8, 47.1+/-3.9, and 82.9+/-6.6 ng/ml. Times to Cmax (Tmax; mean+/-SEM) for men were 1.5+/-0.3, 4.4+/-0.5, and 2.9+/-0.3 hours; Tmax for women were 1.8+/-0.3, 4.1+/-0.4, and 4.4+/-0.6 hours for the three formulations, respectively. Women had a consistently higher AUC for all three formulations than men (p<0.05). With the exception of the 16-mg Polybase formulation in women, the two suppositories closely approximated the pharmacokinetics of the 8-mg oral tablet. These results suggest that gender may be a significant factor in ondansetron's disposition.

Structurally characterized 1,1,3,3-tetramethylguanidine solvated magnesium aryloxide complexes: [Mg(mu-OEt)(DBP)(H-TMG)]2, [Mg(mu-OBc)(DBP)(H-TMG)]2, [Mg(mu-TMBA)(DBP)(H-TMG)]2, [Mg(mu-DPP)(DBP)(H-TMG)]2, [Mg(BMP)2(H-TMG)2], [Mg(O-2,6-Ph2C6H3)2 (H-TMG)2].

PubMed

Monegan, Jessie D; Bunge, Scott D

2009-04-06

The synthesis and structural characterization of several 1,1,3,3-tetramethylguanidine (H-TMG) solvated magnesium aryloxide complexes are reported. Bu(2)Mg was successfully reacted with H-TMG, HOC(6)H(3)(CMe(3))(2)-2,6 (H-DBP), and either ethanol, a carboxylic acid, or diphenyl phosphate in a 1:1 ratio to yield the corresponding [Mg(mu-L)(DBP)(H-TMG)](2) where L = OCH(2)CH(3) (OEt, 1), O(2)CC(CH(3))(3) (OBc, 2), O(2)C(C(6)H(2)-2,4,6-(CH(3))(3)) (TMBA, 3), or O(2)P(OC(6)H(5))(2) (DPP, 4). Bu(2)Mg was also reacted with two equivalents of H-TMG and HOC(6)H(3)(CMe(3))-2-(CH(3))-6 (BMP) or HO-2,6-Ph(2)C(6)H(3) to yield [Mg(BMP)(2)(H-TMG)(2)] (5) and [Mg(O-2,6-Ph(2)C(6)H(3))(2)(H-TMG)(2)] (6). Compounds 1-6 were characterized by single-crystal X-ray diffraction. Polymerization of l- and rac-lactide with 1 was found to generate polylactide (PLA). A discussion concerning the relevance of compounds 2 - 4 to the structure of Mg-activated phosphatase enzymes is also provided. The bulk powders for all complexes were found to be in agreement with the crystal structures based on elemental analyses, FT-IR spectroscopy, and (1)H, (13)C and (31)P NMR studies.

Juvenile delinquency among students of an approved sheltered girls' school in Lagos, Nigeria.

PubMed

Ebuehi, O M; Omogbemi, K B

2011-01-01

Juvenile delinquency is the involvement of a child younger than 18 years in behavior that violates the law. Its cost in terms of human potential, public safety and tax expenditures can be very high. Research that assesses how and why children become delinquent is a sound investment, because it can provide the foundation for effective intervention in its prevention and control. The study is to determine the factors associated with juvenile delinquency. A cross-sectional study was conducted among sixty (60) students of the approved sheltered girls' school, Idi-Araba, Lagos, using a structured interviewer-administered questionnaire. Findings revealed that the respondents were within the ages of 10-18 years with a mean age of 14.2 +/- 2.0 years, 70% had attained primary school education. Of the 53.3% that dropped out of school, 65.6% did so from financial problems, 6.3% as a result of poor performance and peer pressure accounted for 28.1%. A total of 71.7% of the students were brought to the school by the police; 52.5% on account of roaming while lack of parental control, stealing, robbery and fighting accounted for 16.9%, 11.9%, 10.2%, and 8.5% respectively. Majority (58.6%) of the students had both parents alive while 12.1% had both parents deceased. About 25 (41.7%) of the respondents admitted to committing a crime out of which 88% was stealing, 4% were involved in armed robbery and 8% in house breaking. Of all the socio-demographics characteristics of the respondents explored, only their educational level was found to be significantly associated (p = 0.0197) with criminal behaviour. Mother's educational level (p = 0.0245), maternal alcohol consumption (p = 0.0173) and kind of treatment (0.0245) received from step mums were significantly associated with criminal behaviour. Poor parental supervision, poverty and peer pressure played key roles in delinquency among the juveniles. An effective prevention and control of juvenile delinquency will require collective

Cosmogenic Surface-Exposure Dating of Boulders on Last-Glacial and Late-Glacial Moraines, Lago Buenos Aires, Argentina: Interpretive Strategies and Paleoclimate Implications

NASA Astrophysics Data System (ADS)

Douglass, D. C.; Singer, B. S.; Kaplan, M. R.; Mickelson, D. M.; Caffee, M.

2005-12-01

The most substantial and least quantifiable source of uncertainty in cosmogenic surface-exposure datasets is the variable exposure histories of boulders from the same landform. The development of precise and accurate chronologies requires distinguishing boulders that best reflect the age of the landform from those which are outliers. We use the Mean Square of Weighted Deviates statistic and cumulative frequency plots to identify groups of samples that have statistically similar ages based on the number of samples and the uncertainty associated with the analyses. This group of samples most likely represents the best estimate of the landform age. We use these tools to interpret 49 surface-exposure ages from six last-glacial and late-glacial moraines at Lago Buenos Aires, Argentina (LBA; 71.0W, 46.5S). Seven of the orty-nine samples are identified as anomalously young, and are interpreted to have been exhumed after moraine deposition. The remaining samples indicate that glacial advances or still-stands of the ice margin occurred at 22.7±0.9, 21.4±1.9, 19.8±1.1, 17.0±0.8, 15.7±0.6, and 14.4±0.9 ka (±2 σ). This maximum ice extent is roughly synchronous with maximum global ice volume and several of the re-advances are contemporaneous with Heinrich events and other Northern Hemisphere cold periods. The late-glacial readvance at ca. 14.4 ka is contemporaneous with the Antarctic Cold Reversal (ACR), and precedes the Younger Dryas Chronozone (YD). No evidence for a Younger Dryas glacial advance has been found in the Lago Buenos Aires basin. This precise glacial chronology indicates there were significant and important differences in climate across southern South America. The timing of maximum ice extent and onset of deglaciation at LBA occur ~4000 years later than in the Chilean Lake District (41S). Fossil pollen from the CLD area indicates cooler conditions between ca. 14.2 and 11.2, and increased silt in a nearby lake core provides indirect evidence for glacial

Characteristics and outcome of tetanus in adolescent and adult patients admitted to the Lagos University Teaching Hospital between 2000 and 2009.

PubMed

Bankole, Idowu A; Danesi, Mustapha A; Ojo, Oluwadamilola O; Okubadejo, Njideka U; Ojini, Frank I

2012-12-15

This study was a case record review of adult patients with tetanus admitted into Lagos University Teaching Hospital between 2000 and 2009. Of 78,009 adults admitted, 190 had tetanus, constituting 0.25% of admission. Mean age was 30.4 ± 13.8 years. Male to female ratio was 3:1. The commonest occupation was commercial motorcyclists. 96% of the patients were unimmunized and 4% that had partial immunization had localized tetanus. Commonest presentation was trismus (83%). Twenty three patients had complications, 30% had autonomic dysfunction. Mean incubation period was 11.4 ± 4.8 days, and mean duration of onset was 72 ± 45.6h. 31 patients died, case fatality rate was 16.3%. Twelve percent of those with long period of onset died while 43% with short period of onset died (P=0.002). Patients with complications (78%) died of tetanus while only 8% of those without complication died (P<0.0001). Case fatality rate is still unacceptably high for a vaccine preventable disease. Attention to primary prevention of people at risk and active surveillance to prevent complications will further reduce mortality. Copyright © 2012 Elsevier B.V. All rights reserved.

Fast Mg2+ diffusion in Mo3(PO4)3O for Mg batteries.

PubMed

Rong, Ziqin; Xiao, Penghao; Liu, Miao; Huang, Wenxuan; Hannah, Daniel C; Scullin, William; Persson, Kristin A; Ceder, Gerbrand

2017-07-13

In this work, we identify a new potential Mg battery cathode structure Mo 3 (PO 4 ) 3 O, which is predicted to exhibit ultra-fast Mg 2+ diffusion and relatively high voltage based on first-principles density functional theory calculations. Nudged elastic band calculations reveal that the migration barrier of the percolation channel is only ∼80 meV, which is remarkably low, and comparable to the best Li-ion conductors. This low barrier is verified by ab initio molecular dynamics and kinetic Monte Carlo simulations. The voltage and specific energy are predicted to be ∼1.98 V and ∼173 W h kg -1 , respectively. If confirmed by experiments, this material would have the highest known Mg mobility among inorganic compounds.

Microstructure and Phase Evolution in Mg-Gd and Mg-Gd-Nd Alloys With Additions of Zn, Y and Zr

NASA Astrophysics Data System (ADS)

Khawaled, S.; Bamberger, M.; Katsman, A.

Microstructure and phase evolution in Mg-Gd and Mg-Gd-Nd based alloys with additions of Zn, Zr and Y were analyzed in the as-cast, solution treated and aged conditions. Alloys has been investigated after solution treatment at 540°C for 24hr followed by isothermal aging at 175°C up to 32 days by using of Vickers hardness, optical microscopy, scanning electron microscopy equipped with EDS, X-ray diffraction and transmission electron microscopy. It was found that the as-cast alloys contained primary α-Mg matrix, eutecticlike structures, cuboid-like phases and Zr-rich clusters. The homogenized and quenched alloys contained primary α-Mg solid solution, smaller amount of divorced eutectic compounds, enlarged cuboid-like particles and Zr-rich clusters. The eutectic phase was Mg5Gd prototype with the composition Mg5(GdxNd1-x, x≈0.2). The compositions of the cuboid shaped particles are characterized by enlarged amount of Gd and can be written as Mg2(Gd x Y1-x) with x≈0.85 in the Mg-5Gd based alloy, and Gd4(YxNd1-x) with x≈0.5 in the Mg-6Gd-3.7Nd based alloy. The cuboid shaped particles grew during aging and reached 3µm average size. Precipitation of ß″ and ß' phases during aging was observed. Mg-6Gd-3.7Nd based alloy reached a maximum value of microhardness after 16 days of aging; in Mg-Gd based alloy, microhardness increased more slowly and reached a maximum value after 32 days of aging.

Distribution of calcium (Ca) and magnesium (Mg) in the leaves of Brassica rapa under varying exogenous Ca and Mg supply.

PubMed

Rios, Juan Jose; Lochlainn, Seosamh O; Devonshire, Jean; Graham, Neil S; Hammond, John P; King, Graham J; White, Philip J; Kurup, Smita; Broadley, Martin R

2012-05-01

Leafy vegetable Brassica crops are an important source of dietary calcium (Ca) and magnesium (Mg) and represent potential targets for increasing leaf Ca and Mg concentrations through agronomy or breeding. Although the internal distribution of Ca and Mg within leaves affects the accumulation of these elements, such data are not available for Brassica. The aim of this study was to characterize the internal distribution of Ca and Mg in the leaves of a vegetable Brassica and to determine the effects of altered exogenous Ca and Mg supply on this distribution. Brassica rapa ssp. trilocularis 'R-o-18' was grown at four different Ca:Mg treatments for 21 d in a controlled environment. Concentrations of Ca and Mg were determined in fully expanded leaves using inductively coupled plasma-mass spectrometry (ICP-MS). Internal distributions of Ca and Mg were determined in transverse leaf sections at the base and apex of leaves using energy-dispersive X-ray spectroscopy (EDS) with cryo-scanning electron microscopy (cryo-SEM). Leaf Ca and Mg concentrations were greatest in palisade and spongy mesophyll cells, respectively, although this was dependent on exogenous supply. Calcium accumulation in palisade mesophyll cells was enhanced slightly under high Mg supply; in contrast, Mg accumulation in spongy mesophyll cells was not affected by Ca supply. The results are consistent with Arabidopsis thaliana and other Brassicaceae, providing phenotypic evidence that conserved mechanisms regulate leaf Ca and Mg distribution at a cellular scale. The future study of Arabidopsis gene orthologues in mutants of this reference B. rapa genotype will improve our understanding of Ca and Mg homeostasis in plants and may provide a model-to-crop translation pathway for targeted breeding.

Pharmacodynamics of 750 mg and 500 mg doses of levofloxacin against ciprofloxacin-resistant strains of Streptococcus pneumoniae.

PubMed

Lister, Philip D

2002-09-01

An in vitro pharmacokinetic model (IVPM) was used to evaluate the pharmacodynamics of the 750 mg and 500 mg doses of levofloxacin against 4 ciprofloxacin-nonsusceptible Streptococcus pneumoniae. Levofloxacin MICs ranged from 1.4 to 3.2 micro g/ml. Log-phase cultures (5 x 10(7) cfu/ml) were inoculated into the IVPM and exposed to the peak free-drug concentrations of levofloxacin achieved in human serum with each dose. Levofloxacin was dosed at 0 and 24 h, elimination pharmacokinetics were simulated, and viable counts were measured over 30 h. The 750 mg dose was rapidly bactericidal against all 4 strains, achieving eradication within 30 h. Against strains with levofloxacin MICs of 1.4 and 1.8 micro g/ml, the 500 mg dose exhibited pharmacodynamics similar to the 750 mg dose. In contrast, against strains with levofloxacin MICs of 2.6 and 3.2 micro g/ml, viable counts never fell below 10(4) cfu/ml. The rapid killing and eradication of these pneumococci by the 750 mg dose warrant the clinical evaluation of this new dose in the treatment of pneumococcal infections.

Synthesis and characterization of the divalent samarium Zintl-phases SmMg 2Bi 2 and SmMg 2Sb 2

DOE PAGES

Ramirez, D.; Gallagher, A.; Baumbach, R.; ...

2015-08-29

Here, single crystals of LnMg 2Bi 2 (Ln = Yb, Eu, Sm) and SmMg 2Sb 2 were synthesized using Mg-Bi metal and Mg-Sb metal fluxes, respectively. The crystal structures are of the CaAl 2Si 2 type with space group P3 m1 (#164, Z = 1): SmMg 2Bi 2 ( a = 4.7745(1)Å, c = 7.8490(2)Å), EuMg 2Bi 2 ( a = 4.7702(1)Å, c = 7.8457(2) Å), YbMg 2Bi 2 ( a = 4.7317(2)Å, c = 7.6524(3) Å), and SmMg 2Sb 2 ( a = 4.6861(1) Å, c = 7.7192(2) Å). Heat capacity, electrical transport, and magnetization of all bismuth containingmore » phases were measured. The materials behave as “poor metals” with resistivity between 2 and 10 mΩ·cm. Temperature independent Van Vleck paramagnetism is observed in SmMg 2Bi 2 indicative of divalent samarium (Sm 2+) ions.« less

SOLID SOLUTION EFFECTS ON THE THERMAL PROPERTIES IN THE MgAl2O4-MgGa2O4

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Hara, Kelley; Smith, Jeffrey D; Sander, Todd P.

Solid solution eects on thermal conductivity within the MgO-Al2O3-Ga2O3 system were studied. Samples with systematically varied additions of MgGa2O4 to MgAl2O4 were prepared and the laser ash technique was used to determine thermal diusivity at temperatures between 200C and 1300C. Heat capacity as a function of temperature from room temperature to 800C was also determined using dierential scanning calorimetry. Solid solution in the MgAl2O4-MgGa2O4 system decreases the thermal conductivity up to 1000C. At 200C thermal conductivity decreased 24% with a 5 mol% addition of MgGa2O4 to the system. At 1000C the thermal conductivity decreased 13% with a 5 mol% addition.more » Steady state calculations showed a 12.5% decrease in heat ux with 5 mol% MgGa2O4 considered across a 12 inch thickness.« less

Pharmacokinetics, Safety, and Tolerability of a Single 500-mg or 1000-mg Intravenous Dose of Dalbavancin in Healthy Japanese Subjects.

PubMed

Scoble, Patrick J; Owens, Robert C; Puttagunta, Sailaja; Yen, Mark; Dunne, Michael W

2015-12-01

Dalbavancin is a novel, once-weekly glycopeptide antibiotic approved for treatment of acute bacterial skin infections. Given the importance of understanding any pharmacokinetic variability across different patient populations, a double-blind, placebo-controlled study was conducted to evaluate the pharmacokinetics, safety, and tolerability of a single 500-mg and a single 1000-mg intravenous dose of dalbavancin in healthy Japanese subjects. Ten subjects received intravenous dalbavancin 1000 mg, five subjects received intravenous dalbavancin 500 mg, and three subjects received intravenous placebo. After a single infusion of dalbavancin, the maximal plasma concentration (C max) and area under the plasma concentration-time curve (AUC) increased in a proportional manner from 500 mg to 1000 mg (C max: 157 μg/ml and 299 μg/ml; AUClast: 10,850 μg·h/ml and 22,679 μg·h/ml, on the 500-mg and 1000-mg regimens, respectively) with low inter-subject variability. The mean terminal phase half-life (t 1/2) was 204 and 193 h after the 500-mg and 1000-mg dose, respectively. Clearance and volume of distribution were similar for the two dose concentrations. Treatment-emergent adverse events reported were considered to be of mild intensity. There were no relevant changes in laboratory values or vital signs over time in subjects in either treatment group. Overall, dalbavancin 500 mg and dalbavancin 1000 mg, administered as a single 30-min infusion, was well tolerated in this population and resulted in plasma exposures similar to those in non-Asians.

Quaternary BeMgZnO by plasma-enhanced molecular beam epitaxy for BeMgZnO/ZnO heterostructure devices

NASA Astrophysics Data System (ADS)

Ullah, M. B.; Toporkov, M.; Avrutin, V.; Özgür, Ü.; Smith, D. J.; Morkoç, H.

2017-02-01

We investigated the crystal structure, growth kinetics and electrical properties of BeMgZnO/ZnO heterostructures grown by Molecular Beam Epitaxy (MBE). Transmission Electron Microscopy (TEM) studies revealed that incorporation of Mg into the BeZnO solid solution eliminates the high angle grain boundaries that are the major structural defects in ternary BeZnO. The significant improvement of x-ray diffraction intensity from quaternary BeMgZnO alloy compared to ternary BeZnO was attributed to the reduction of lattice strain, which is present in the latter due to the large difference of covalent radii between Be and Zn (1.22 Å for Zn, 0.96 Å for Be). Incorporation of Mg, which has a larger covalent radius of 1.41Å, reduced the strain in BeMgZnO thin films and also enhanced Be incorporation on lattice sites in the wurtzite lattice. The Zn/(Be + Mg) ratio necessary to obtain single-crystal O-polar BeMgZnO on (0001) GaN/sapphire templates was found to increase with increasing substrate temperature:3.9, 6.2, and 8.3 at substrate temperatures of 450°C, 475°C, and 500°C, respectively. Based on analysis of photoluminescence spectra from Be0.03MgyZn0.97-yO and evolution of reflection high-energy electron diffraction patterns observed in situ during the MBE growth, it has been deduced that more negative formation enthalpy of MgO compared to ZnO and the increased surface mobility of Mg adatoms at elevated substrate temperatures give rise to the nucleation of a MgO-rich wurtzite phase at relatively low Zn/(Be + Mg) ratios. We have demonstrated both theoretically and experimentally that the incorporation of Be into the barrier in Zn-polar BeMgZnO/ZnO and O-polar ZnO/BeMgZnO polarization doped heterostructures allows the alignment of piezoelectric polarization vector with that of spontaneous polarization due to the change of strain sign, thus increasing the amount of net polarization. This made it possible to achieve Zn-polar BeMgZnO/ZnO heterostructures grown on Ga

Highly Active Electrolytes for Rechargeable Mg Batteries Based on [Mg2(μ-Cl)2]2+ Cation Complex in Dimethoxyethane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Yingwen; Stolley, Ryan M.; Han, Kee Sung

2015-01-01

Highly active electrolytes based on a novel [Mg2(μ-Cl)2]2+ cation complex for reversible Mg deposition were developed and analyzed in this work. These electrolytes were formulated in dimethoxyethane through dehalodimerization of non-nucleophilic MgCl2 by reacting with either Mg salts (such as Mg(TFSI)2, TFSI= bis(trifluoromethane)sulfonylimide) or Lewis acid salts (such as AlEtCl2 or AlCl3). The cation complex was identified for the first time as [Mg2(μ-Cl)2(DME)4]2+ (DME=dimethoxyethane) and its molecular structure was characterized by single crystal X-ray diffraction, Raman spectroscopy and NMR. The electrolyte synthesis process was studied and rational approaches for formulating highly active electrolytes were proposed. Through control of the anions,more » electrolytes with efficiency close to 100%, wide electrochemical window (up to 3.5V) and high ionic conductivity (> 6 mS/cm) were obtained. The electrolyte synthesis and understandings developed in this work could bring significant opportunities for rational formulation of electrolytes with the general formula [Mg2(μ-Cl)2(DME)4][anion]x for practical Mg batteries.« less

Enhanced bioactivity of Mg-Nd-Zn-Zr alloy achieved with nanoscale MgF2 surface for vascular stent application.

PubMed

Mao, Lin; Shen, Li; Chen, Jiahui; Wu, Yu; Kwak, Minsuk; Lu, Yao; Xue, Qiong; Pei, Jia; Zhang, Lei; Yuan, Guangyin; Fan, Rong; Ge, Junbo; Ding, Wenjiang

2015-03-11

Magnesium (Mg) alloys have revolutionized the application of temporary load-bearing implants as they meet both engineering and medical requirements. However, rapid degradation of Mg alloys under physiological conditions remains the major obstacle hindering the wider use of Mg-based implants. Here we developed a simple method of preparing a nanoscale MgF2 film on Mg-Nd-Zn-Zr (denoted as JDBM) alloy, aiming to reduce the corrosion rate as well as improve the biological response. The corrosion rate of JDBM alloy exposed to artificial plasma is reduced by ∼20% from 0.337 ± 0.021 to 0.269 ± 0.043 mm·y(-1) due to the protective effect of the MgF2 film with a uniform and dense physical structure. The in vitro cytocompatibility test of MgF2-coated JDBM using human umbilical vein endothelial cells indicates enhanced viability, growth, and proliferation as compared to the naked substrate, and the MgF2 film with a nanoscale flakelike feature of ∼200-300 nm presents a much more favorable environment for endothelial cell adhesion, proliferation, and alignment. Furthermore, the animal experiment via implantation of MgF2-coated JDBM stent to rabbit abdominal aorta confirms excellent tissue compatibility of the well re-endothelialized stent with no sign of thrombogenesis and restenosis in the stented vessel.

Effect of amorphous Mg{sub 50}Ni{sub 50} on hydriding and dehydriding behavior of Mg{sub 2}Ni alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guzman, D., E-mail: danny.guzman@uda.cl; Ordonez, S.; Fernandez, J.F.

Composite Mg{sub 2}Ni (25 wt.%) amorphous Mg{sub 50}Ni{sub 50} was prepared by mechanical milling starting with nanocrystalline Mg{sub 2}Ni and amorphous Mg{sub 50}Ni{sub 50} powders, by using a SPEX 8000 D mill. The morphological and microstructural characterization of the powders was performed via scanning electron microscopy and X-ray diffraction. The hydriding characterization of the composite was performed via a solid gas reaction method in a Sievert's-type apparatus at 363 K under an initial hydrogen pressure of 2 MPa. The dehydriding behavior was studied by differential thermogravimetry. On the basis of the results, it is possible to conclude that amorphous Mg{submore » 50}Ni{sub 50} improved the hydriding and dehydriding kinetics of Mg{sub 2}Ni alloy upon cycling. A tentative rationalization of experimental observations is proposed. - Research Highlights: {yields} First study of the hydriding behavior of composite Mg{sub 2}Ni (25 wt.%) amorphous Mg{sub 50}Ni{sub 50}. {yields} Microstructural characterization of composite material using XRD and SEM was obtained. {yields} An improved effect of Mg{sub 50}Ni{sub 50} on the Mg{sub 2}Ni hydriding behavior was verified. {yields} The apparent activation energy for the hydrogen desorption of composite was obtained.« less

Size effects in MgO cube dissolution.

PubMed

Baumann, Stefan O; Schneider, Johannes; Sternig, Andreas; Thomele, Daniel; Stankic, Slavica; Berger, Thomas; Grönbeck, Henrik; Diwald, Oliver

2015-03-10

Stability parameters and dissolution behavior of engineered nanomaterials in aqueous systems are critical to assess their functionality and fate under environmental conditions. Using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, we investigated the stability of cubic MgO particles in water. MgO dissolution proceeding via water dissociation at the oxide surface, disintegration of Mg(2+)-O(2-) surface elements, and their subsequent solvation ultimately leads to precipitation of Mg(OH)2 nanosheets. At a pH ≥ 10, MgO nanocubes with a size distribution below 10 nm quantitatively dissolve within few minutes and convert into Mg(OH)2 nanosheets. This effect is different from MgO cubes originating from magnesium combustion in air. With a size distribution in the range 10 nm ≤ d ≤ 1000 nm they dissolve with a significantly smaller dissolution rate in water. On these particles water induced etching generates (110) faces which, above a certain face area, dissolve at a rate equal to that of (100) planes.1 The delayed solubility of microcrystalline MgO is attributed to surface hydroxide induced self-inhibition effects occurring at the (100) and (110) microplanes. The present work underlines the importance of morphology evolution and surface faceting of engineered nanomaterials particles during their dissolution.

Loss of Endothelial Barrier in Marfan Mice (mgR/mgR) Results in Severe Inflammation after Adenoviral Gene Therapy

PubMed Central

Weymann, Alexander; Arif, Rawa; Weber, Antje; Zaradzki, Marcin; Richter, Karsten; Ensminger, Stephan; Robinson, Peter Nicholas; Wagner, Andreas H.; Karck, Matthias; Kallenbach, Klaus

2016-01-01

Objectives Marfan syndrome is an autosomal dominant inherited disorder of connective tissue. The vascular complications of Marfan syndrome have the biggest impact on life expectancy. The aorta of Marfan patients reveals degradation of elastin layers caused by increased proteolytic activity of matrix metalloproteinases (MMPs). In this study we performed adenoviral gene transfer of human tissue inhibitor of matrix metalloproteinases-1 (hTIMP-1) in aortic grafts of fibrillin-1 deficient Marfan mice (mgR/mgR) in order to reduce elastolysis. Methods We performed heterotopic infrarenal transplantation of the thoracic aorta in female mice (n = 7 per group). Before implantation, mgR/mgR and wild-type aortas (WT, C57BL/6) were transduced ex vivo with an adenoviral vector coding for human TIMP-1 (Ad.hTIMP-1) or β-galactosidase (Ad.β-Gal). As control mgR/mgR and wild-type aortas received no gene therapy. Thirty days after surgery, overexpression of the transgene was assessed by immunohistochemistry (IHC) and collagen in situ zymography. Histologic staining was performed to investigate inflammation, the neointimal index (NI), and elastin breaks. Endothelial barrier function of native not virus-exposed aortas was evaluated by perfusion of fluorescent albumin and examinations of virus-exposed tissue were performed by transmission electron microscopy (TEM). Results IHC and ISZ revealed sufficient expression of the transgene. Severe cellular inflammation and intima hyperplasia were seen only in adenovirus treated mgR/mgR aortas (Ad.β-Gal, Ad.hTIMP-1 NI: 0.23; 0.43), but not in native and Ad.hTIMP-1 treated WT (NI: 0.01; 0.00). Compared to native mgR/mgR and Ad.hTIMP-1 treated WT aorta, the NI is highly significant greater in Ad.hTIMP-1 transduced mgR/mgR aorta (p = 0.001; p = 0.001). As expected, untreated Marfan grafts showed significant more elastolysis compared to WT (p = 0.001). However, elastolysis in Marfan aortas was not reduced by adenoviral overexpression of hTIMP-1

Resetting of Mg isotopes between calcite and dolomite during burial metamorphism: Outlook of Mg isotopes as geothermometer and seawater proxy

NASA Astrophysics Data System (ADS)

Hu, Zhongya; Hu, Wenxuan; Wang, Xiaomin; Lu, Yizhou; Wang, Lichao; Liao, Zhiwei; Li, Weiqiang

2017-07-01

Magnesium isotopes are an emerging tool to study the geological processes recorded in carbonates. Calcite, due to its ubiquitous occurrence and the large Mg isotope fractionation associated with the mineral, has attracted great interests in applications of Mg isotope geochemistry. However, the fidelity of Mg isotopes in geological records of carbonate minerals (e.g., calcite and dolomite) against burial metamorphism remains poorly constrained. Here we report our investigation on the Mg isotope systematics of a dolomitized Middle Triassic Geshan carbonate section in eastern China. Magnesium isotope analysis was complemented by analyses of Sr-C-O isotopic compositions, major and trace element concentrations, and petrographic and mineralogical features. Multiple lines of evidence consistently indicated that post-depositional diagenesis of carbonate minerals occurred to the carbonate rocks. Magnesium isotope compositions of the carbonate rocks closely follow a mixing trend between a high δ26Mg dolomite end member and a low δ26Mg calcite end member, irrespective of sample positions in the section and calcite/dolomite ratio in the samples. By fitting the measured Mg isotope data using a two-end member mixing model, an inter-mineral Δ26Mgdolomite-calcite fractionation of 0.72‰ was obtained. Based on the experimentally derived Mg isotope fractionation factors for dolomite and calcite, a temperature of 150-190 °C was calculated to correspond to the 0.72‰ Δ26Mgdolomite-calcite fractionation. Such temperature range matches with the burial-thermal history of the local strata, making a successful case of Mg isotope geothermometry. Our results indicate that both calcite and dolomite had been re-equilibrated during burial metamorphism, and based on isotope mass balance of Mg, the system was buffered by dolomite in the section. Therefore, burial metamorphism may reset Mg isotope signature of calcite, and Mg isotope compositions in calcite should be dealt with caution in

Effect of amorphous lamella on the crack propagation behavior of crystalline Mg/amorphous Mg-Al nanocomposites

NASA Astrophysics Data System (ADS)

Hai-Yang, Song; Yu-Long, Li

2016-02-01

The effects of amorphous lamella on the crack propagation behavior in crystalline/amorphous (C/A) Mg/Mg-Al nanocomposites under tensile loading are investigated using the molecular dynamics simulation method. The sample with an initial crack of orientation [0001] is considered here. For the nano-monocrystal Mg, the crack growth exhibits brittle cleavage. However, for the C/A Mg/Mg-Al nanocomposites, the ‘double hump’ behavior can be observed in all the stress-strain curves regardless of the amorphous lamella thickness. The results indicate that the amorphous lamella plays a critical role in the crack deformation, and it can effectively resist the crack propagation. The above mentioned crack deformation behaviors are also disclosed and analyzed in the present work. The results here provide a strategy for designing the high-performance hexagonal-close-packed metal and alloy materials. Project supported by the National Natural Science Foundation of China (Grant Nos. 11372256 and 11572259), the 111 Project (Grant No. B07050), the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No. NCET-12-1046), and the Program for New Scientific and Technological Star of Shaanxi Province, China (Grant No. 2012KJXX-39).

Bioavailability, safety, and pharmacodynamics of delayed-release dexlansoprazole administered as two 30 mg orally disintegrating tablets or one 60 mg capsule.

PubMed

Kukulka, Michael; Nudurupati, Sai; Perez, Maria Claudia

2016-11-01

Dual delayed-release dexlansoprazole is approved for use in adults as a 30 mg orally disintegrating tablet (ODT) or as 30 mg and 60 mg capsules. The pharmacokinetics, pharmacodynamics, and safety profile of two dexlansoprazole 30 mg ODTs were compared with one dexlansoprazole 60 mg capsule in this randomized, phase I, open-label, single-center, multiple-dose, two-period crossover study. Participants were randomized in one of two treatment sequences, each comprised two 5-day treatment periods during which two dexlansoprazole 30 mg ODTs or one 60 mg capsule was administered once daily. Pharmacokinetic parameters and the mean intragastric pH profile for the 24-hour period after dosing on days 1 and 5 were described. Adverse events were monitored during study duration and followed up with a phone call 5-10 days after the last dose of study drug. On day 1, peak observed plasma concentration ( C max ) values were similar between two 30 mg ODTs (1047 ng/ml) and one 60 mg capsule (1164 ng/ml). Systemic exposure, measured by the area under the plasma concentration-time curve (AUC), was approximately 25% lower after ODT administration. On day 5, mean pH after daily doses of two 30 mg ODT or one 60 mg capsule was 4.33 and 4.36, respectively; both regimens maintained intragastric pH above 4.0 for 60% of the 24-hour period. Headache was the most commonly reported adverse event (observed in 19.2% of participants); no adverse events leading to study withdrawal occurred. While systemic exposure (AUC) was 25% lower with ODT, peak concentrations ( C max ) after administration of two dexlansoprazole 30 mg ODTs and one 60 mg capsule were similar. The 24-hour intragastric pH control after administration of two dexlansoprazole 30 mg ODTs was equivalent to one dexlansoprazole 60 mg capsule. Both ODT and capsule were well tolerated.

High-precision Mg isotopic systematics of bulk chondrites

NASA Astrophysics Data System (ADS)

Schiller, Martin; Handler, Monica R.; Baker, Joel A.

2010-08-01

Variations of the mass-independent abundance of 26Mg ( δ26Mg*) and stable Mg ( δ25Mg) isotope composition of chondrites are important because they constrain the homogeneity of 26Al and Mg isotopes in the proto-planetary disc and the validity of the short-lived 26Al-to- 26Mg chronometer applied to meteorites. We present high-precision Mg isotope data and Al/Mg ratios of chondrites representing nearly all major chondrite classes, including a step-leaching experiment on the CM2 chondrite Murchison. δ26Mg* variations in leachates of Murchison representing acid soluble material are ≤ 30 times smaller than reported for neutron-rich isotopes of Ti and Cr and do not reveal resolvable deficits in δ26Mg* (-0.002 to + 0.118‰). Very small variations in δ26Mg* anomalies in bulk chondrites (-0.006 to + 0.019‰) correlate with increasing 27Al/ 24Mg ratios and δ50Ti, reflecting the variable presence of calcium-aluminium-rich inclusions (CAIs) in some types of carbonaceous chondrites. Similarly, release of radiogenic 26Mg produced by 26Al decay from CAI material in the step-leaching of Murchison best explains the high δ26Mg* observed in the last, aggressive, leaching steps of this experiment. Overall, the observed variations in δ26Mg* are small and potential differences beyond that which result from the presence of CAI-like material cannot be detected within the analytical uncertainties of this study (± 0.004‰). The results do not allow radical heterogeneity of 26Al (≥±30%) or measurable Mg nucleosynthetic heterogeneity (≥±0.005‰) to have existed on a planetesimal scale in the proto-planetary disc. Combined with published δ26Mg* data for CAIs, the bulk chondrite data yield a precise initial ( 26Al/ 27Al) 0 = (5.21 ± 0.06) × 10 -5 and δ26Mg* = -0.0340 ± 0.0016‰ for the Solar System. However, it is not possible with the currently available data to determine with certainty whether CAIs and the material from which planetesimals accreted including

Radio refractivity gradients in the lowest 100m of the atmosphere over Lagos, Nigeria in the rainy-harmattan transition phase

NASA Astrophysics Data System (ADS)

Dairo, O. F.; Kolawole, L. B.

2018-01-01

Radio engineers and researchers in conjunction with the International Telecommunication Union (ITU) have established the pivotal role of radio refractivity to the propagation of electromagnetic energy in the troposphere. In particular, the refractivity gradient statistics for the lowest 100m in the troposphere are used to determine the probability of occurrence of anomalous propagation conditions known as ducting. The major challenge to characterising the propagation condition over any environment is accessing the data of the lowest boundary layer of the atmosphere, which is highly dynamic and turbulent in evolution. High resolution radiosonde data from the Nigerian Meteorological Agency (NiMet) were used for a synoptic study of the rain-harmattan transition phase. The rain-harmattan transition phase marks the onset of the dry season due to the movement of the intertropical convergence zone interplay between (north-easterly and south-westerly) trade winds and monsoonal circulation. The lowest 100m data were analysed to determine the frequency of ducting per month. Progressive increase in the occurrence of ducting was observed during the rain-harmattan transition phase, which coincides with the West African Monsoon retreat. The results show significant divergence from previous studies, which reported that the tropospheric condition over Lagos (Geo. 6 . 5 °N, 3 . 3 °E), Nigeria, is predominantly super-refractive.

Mg2BIV: Narrow Bandgap Thermoelectric Semiconductors

NASA Astrophysics Data System (ADS)

Kim, Il-Ho

2018-05-01

Thermoelectric materials can convert thermal energy directly into electric energy and vice versa. The electricity generation from waste heat via thermoelectric devices can be considered as a new energy source. For instance, automotive exhaust gas and all industrial processes generate an enormous amount of waste heat that can be converted to electricity by using thermoelectric devices. Magnesium compound Mg2BIV (BIV = Si, Ge or Sn) has a favorable combination of physical and chemical properties and can be a good base for the development of new efficient thermoelectrics. Because they possess similar properties to those of group BIV elemental semiconductors, they have been recognized as good candidates for thermoelectric applications. Mg2Si, Mg2Ge and Mg2Sn with an antifluorite structure are narrow bandgap semiconductors with indirect band gaps of 0.77 eV, 0.74 eV, and 0.35 eV, respectively. Mg2BIV has been recognized as a promising material for thermoelectric energy conversion at temperatures ranging from 500 K to 800 K. Compared to other thermoelectric materials operating in the similar temperature range, such as PbTe and filled skutterudites, the important aspects of Mg2BIV are non-toxic and earth-abundant elements. Based on classical thermoelectric theory, the material factor β ( m* / m e)3/2μκ L -1 can be utilized as the criterion for thermoelectric material selection, where m* is the density-of-states effective mass, me is the mass of an electron, μ is the carrier mobility, and κL is the lattice thermal conductivity. The β for magnesium silicides is 14, which is very high compared to 0.8 for iron silicides, 1.4 for manganese silicides, and 2.6 for silicon-germanium alloys. In this paper, basic phenomena of thermoelectricity and transport parameters for thermoelectric materials were briefly introduced, and thermoelectric properties of Mg2BIV synthesized by using a solid-state reaction were reviewed. In addition, various Mg2BIV compounds were discussed

Misfit paradox on nucleation potency of MgO and MgAl{sub 2}O{sub 4} for Al

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, D.; Wang, L.

MgO and MgAl{sub 2}O{sub 4} are believed to be effective heterogeneous nuclei for Al based alloys due to their small lattice misfits with Al. However, there is a strong evidence to suggest that liquid Al reacts with MgO and MgAl{sub 2}O{sub 4} phases but the heterogeneous nucleation behavior of such phases is rarely discussed. In order to identify the nucleation mechanism of Al, under the interference of the chemical reaction, the heterogeneous nucleation process is systematically investigated through thermal analysis and high resolution transmission electron microscopy (HRTEM). The observed multi-nucleation interfaces (Al/MgO, Al/MgAl{sub 2}O{sub 4} and Al/Al{sub 2}O{sub 3}) andmore » scattered experimental undercooling data indicate an independent multi-phase nucleation process in these systems. - Highlights: •Theoretical lattice misfit doesn’t always disclose nucleation potency. •The nucleation of liquid can be triggered by multi-nucleation interfaces. •An independent multi-agents nucleation was verified in the study.« less

Synthesis and luminescence studies of Tb-doped MgO-MgAl2O4-Mg2SiO4 ceramic for use in radiation dosimetry.

PubMed

Gugliotti, C; Moriya, K; Tatumi, S; Mittani, J

2018-05-01

In the present work, MgO ceramic samples with different terbium concentrations were produced and the Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) properties analyzed and discussed, aiming the use in radiation dosimetry. The samples were produced using MgO, Mg(NO 3 ) 2 ·6H 2 O, Al 2 O 3 , SiO 2 and Tb(NO 3 ) 3 ·6H 2 O precursors in stoichiometric concentrations with five different terbium concentrations between 0.1 and 0.5 mol% and after, heat-treated at high temperature ~1500 °C. X-ray diffraction measurements on samples showed the formation of MgO as principal phase, and others in low concentration due to MgAl 2 O 4 , Mg 2 SiO 4 and Tb 4 O 7 phases. The TL glow curve of samples showed an intense and well-defined peak having the maximum at ~210 °C and other less intense at ~350 °C. The sample with 0.1 mol% of terbium concentration presented highest luminescence peak when compared to the other samples. The relationship between 210 °C TL peak intensity and dose was linear to doses between 1 and 20 Gy and the minimum detectable dose obtained by interpolation taking into account three times the standard deviation of the zero dose reading, was ~40 μGy. A fading of ~20% during the first 5 hours after irradiation of 210 °C peak was observed. TL emission spectra showed strong emission lines due to Tb 3+ ion. The OSL signal presented a linear behavior to doses between 1 and 10 Gy using 532 nm wavelength stimulation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mg-isotopic fractionation in the manila clam (Ruditapes philippinarum): New insights into Mg incorporation pathway and calcification process of bivalves

NASA Astrophysics Data System (ADS)

Planchon, Frédéric; Poulain, Céline; Langlet, Denis; Paulet, Yves-Marie; André, Luc

2013-11-01

We estimate the magnesium stable isotopic composition (δ26Mg) of the major compartments involved in the biomineralisation process of euryhaline bivalve, the manila clam Ruditapes philippinarum. Our aim is to identify the fractionation processes associated with Mg uptake and its cycling/transport in the bivalve organism, in order to better assess the controlling factors of the Mg isotopic records in bivalve shells. δ26Mg were determined in seawater, in hemolymph, extrapallial fluid (EPF), soft tissues and aragonitic shell of adult clams collected along the Auray River estuary (Gulf of Morbihan, France) at two sites showing contrasted salinity regimes. The large overall δ26Mg variations (4.16‰) demonstrate that significant mass-dependent Mg isotopic fractionations occur during Mg transfer from seawater to the aragonitic shell. Soft tissues span a range of fractionation factors relative to seawater (Δ26Mgsoft tissue-seawater) of 0.42 ± 0.12‰ to 0.76 ± 0.12‰, and show evidence for biological isotopic fractionation of Mg. Hemolymph and EPF are on average isotopically close to seawater (Δ26Mghemolymph-seawater = -0.20 ± 0.27‰; 2 sd; n = 5 and Δ26MgEPF-seawater = -0.23 ± 0.25‰; 2 sd; n = 5) indicating (1) a predominant seawater origin for Mg in the intercellular medium and (2) a relatively passive transfer route through the bivalve organism into the calcifying fluid. The lightest isotopic composition is found in shell, with δ26Mg ranging from -1.89 ± 0.07‰ to -4.22 ± 0.06‰. This range is the largest in the dataset and is proposed to result from a combination of abiotic and biologically-driven fractionation processes. Abiotic control includes fractionation during precipitation of aragonite and accounts for Δ26Mgaragonite-seawater ≈ 1000 ln αaragonite-seawater = -1.13 ± 0.28‰ at 20 °C based on literature data. Deviations from inorganic precipitate (expressed as Δ26MgPhysiol) appear particularly variable in the clam shell, ranging from 0

Review of Dextromethorphan 20 mg/Quinidine 10 mg (NUEDEXTA(®)) for Pseudobulbar Affect.

PubMed

Pioro, Erik P

2014-06-01

Pseudobulbar affect (PBA) is a dysfunction of emotional expression characterized by involuntary outbursts of crying or laughing disproportionate or unrelated to mood, occurring in patients with various underlying neurologic disorders. This review describes the clinical data supporting dextromethorphan (DM) hydrobromide combined with quinidine sulfate (Q) as treatment of PBA and briefly surveys the ongoing debates concerning the terminology for dysfunction of emotional expression, as well as the ongoing searches for its brain substrates. Until recently, pharmacologic intervention consisted chiefly of off-label antidepressants. In October 2010, however, DM/Q at 20/10 mg twice daily received approval from the United States Food and Drug Administration for PBA in any setting, and in June 2013, dosages of 20/10 and 30/10 mg twice daily (labeled as 15/9 and 23/9 mg, respectively, DM/Q base) received approval from the European Medicines Agency. DM is an uncompetitive N-methyl-d-aspartate (NMDA) glutamate receptor antagonist, a sigma-1 receptor agonist, and a serotonin and norepinephrine reuptake inhibitor. To block DM hepatic metabolism, thereby increasing DM bioavailability, Quinidine, a cytochrome P450 2D6 inhibitor, is coadministered at a dosage well below those for treating cardiac arrhythmia. Three large-scale DM/Q trials have utilized PBA-episode counts and the Center for Neurologic Study-Lability Scale (CNS-LS), a validated PBA rating scale, to measure efficacy. In a 4-week study of patients with PBA in amyotrophic lateral sclerosis (ALS), DM/Q 30/30 mg was superior to its component drugs. A 12-week, double-blind, placebo-controlled study of DM/Q 30/30 mg showed similar efficacy in patients with PBA in multiple sclerosis (MS). A subsequent 12-week study of patients with PBA and ALS or MS showed superiority to placebo for the 20/10 and 30/10 mg doses. Efficacy was maintained during a 12-week, open-label extension (30/10 mg dose), with further improvement of

Comparison of the efficacy and safety of bilastine 20 mg vs desloratadine 5 mg in seasonal allergic rhinitis patients.

PubMed

Bachert, C; Kuna, P; Sanquer, F; Ivan, P; Dimitrov, V; Gorina, M M; van de Heyning, P; Loureiro, A

2009-01-01

Bilastine is a novel, nonsedating H(1)-antihistamine developed for symptomatic treatment of Allergic Rhinitis and Chronic Idiopathic Urticaria. The objective of this study was to compare the efficacy and safety of bilastine 20 mg vs placebo and desloratadine 5 mg in subjects with seasonal allergic rhinitis (SAR). This randomized, double blind, placebo-controlled, parallel-group multicentre study evaluated the effect of 2 weeks' treatment with bilastine 20 mg, desloratadine 5 mg or matched placebo once daily, in 12-70 years old symptomatic SAR patients. All subjects assessed the severity of nasal (obstruction, rhinorrhoea, itching, and sneezing) and nonnasal (ocular itching, tearing, ocular redness, itching of ears and/or palate) symptoms on a predetermined scale to provide a total symptom score (TSS), composed of nasal and nonnasal symptom scores (NSS and NNSS, respectively). The primary efficacy measure was the area under the curve (AUC) for the TSS over the entire treatment period. Bilastine 20 mg significantly reduced the AUC of TSS to a greater degree from baseline compared to placebo (98.4 with bilastine vs 118.4 with placebo; P < 0.001), but not compared to desloratadine 5 mg (100.5). Bilastine 20 mg was not different from desloratadine 5 mg but significantly more effective than placebo in improving the NSS, NNSS, and rhinitis-associated discomfort scores (P < 0.05), and rhinoconjunctivitis quality of life questionnaire total (P < 0.005) and four out of seven individual domain (P < 0.05) scores. The incidence of treatment emergent adverse events was similar for bilastine (20.6%), desloratadine (19.8%), and placebo (18.8%). Bilastine 20 mg once daily was efficacious, safe and not different from desloratadine 5 mg once daily in the treatment of SAR symptoms.

Thermoluminescence responses of photon- and electron-irradiated lithium potassium borate co-doped with Cu+Mg or Ti+Mg.

PubMed

Alajerami, Y S M; Hashim, S; Ramli, A T; Saleh, M A; Saripan, M I; Alzimami, K; Min Ung, Ngie

2013-08-01

New glasses Li2CO3-K2CO3-H3BO3 (LKB) co-doped with CuO and MgO, or with TiO2 and MgO, were synthesized by the chemical quenching technique. The thermoluminescence (TL) responses of LKB:Cu,Mg and LKB:Ti,Mg irradiated with 6 MV photons or 6 MeV electrons were compared in the dose range 0.5-4.0 Gy. The standard commercial dosimeter LiF:Mg,Ti (TLD-100) was used to calibrate the TL reader and as a reference in comparison of the TL properties of the new materials. The dependence of the responses of the new materials on (60)Co dose is linear in the range of 1-1000 Gy. The TL yields of both of the co-doped glasses and TLD-100 are greater for electron irradiation than for photon irradiation. The TL sensitivity of LKB:Ti,Mg is 1.3 times higher than the sensitivity of LKB:Cu,Mg and 12 times less than the sensitivity of TLD-100. The new TL dosimetric materials have low effective atomic numbers, good linearity of the dose responses, excellent signal reproducibility, and a simple glow curve structure. This combination of properties makes them suitable for radiation dosimetry. Copyright © 2013 Elsevier Ltd. All rights reserved.

Wasting and stunting are still prevalent in children with sickle cell anaemia in Lagos, Nigeria.

PubMed

Esezobor, Christopher I; Akintan, Patricia; Akinsulie, Adebola; Temiye, Edamisan; Adeyemo, Titilope

2016-05-04

Sickle cell anaemia (SCA) is associated with growth failure. However, recent reports indicate high rates of overweight or obesity among children with SCA in developed countries. It is unclear whether overweight or obesity is also common in children with SCA in developing countries. The objectives of the study were to determine the prevalence of overweight or obesity, wasting and stunting and identify predictors of wasting and stunting among children with SCA in Nigeria. Children with SCA attending a public-funded tertiary hospital clinic were studied. Weight, height, haemoglobin, haemoglobin fractions and white cell count were measured. Anthropometric values were converted to z scores and referenced to the WHO Child Growth Standards and WHO Reference 2007. The proportions with wasting, stunting and overweight or obesity were determined. Regression analysis was used to identify the predictors of wasting and stunting. Two hundred and thirty-three children [mean (±SD) age of 9.0 (±4.0) years, 60.9 % males] participated in the study. Wasting, stunting and overweight or obesity rates were 22.7 %, 11.6 % and 1.7 %, respectively. Boys and children from low socioeconomic class were 3.25 (1.45-7.29) and 2.42 (1.14-5.18) times more likely to be wasted respectively, while both wasting and stunting were more common with increasing age [adjusted OR of 1.33 (1.18-1.51) and 1.15 (1.01-1.32) respectively]. Sickle cell-related complications and intake of oral penicillin and hydroxyurea were not associated with wasting and stunting. Overweight or obesity is uncommon while wasting and stunting are still prevalent in children with SCA in Lagos. The strongest predictors of wasting and stunting were older age, male gender and low socioeconomic status.

Comparative performance of a combined injectable contraceptive (50 mg norethisterone enanthate plus 5mg estradiol valerate) and a combined oral contraceptive (0.15 mg levonorgestrel plus 0.03 mg ethinyl estradiol) in adolescents.

PubMed

Molina, Ramiro C; Sandoval, Jorge Z; Montero, Adela V; Oyarzún, Pamela G; Molina, Temístocles G; González, Electra A

2009-02-01

To compare in a regular non-clinical trial experience the efficacy, acceptability, and continuation rates of an injectable contraceptive containing 50 mg norethisterone enanthate plus 5mg estradiol valerate (IC) and an oral contraceptive containing 0.15 mg levonorgestrel plus 0.03 mg ethinyl estradiol (OC), among adolescent users. A total of 251 adolescents ages 14-19 were followed during 12 months. The IC group (124 subjects) was studied for 1044 cycles and the OC group (127 subjects) was studied for 1368 cycles. The users were not assigned in a random selection. Information was collected from clinical records. Groups were compared using Pearson chi-square, odds ratio (95% confidence interval), t-test, and proportion difference test. The IC group had significant differences in baseline social risk, confidence, psychiatric problems, consumption of alcohol, and number of sexual partners. At 12 months, the IC group showed significant decrease in weight and increase in hypermenorrhea. In the OC group, dysmenorrhea decreased, and hypomenorrhea and regular cycles were significantly more frequent. One pregnancy occurred in the OC group (Pearl Index: 0.88). Final continuation rates at 12 months were 41.9% and 37.8% for IC and OC, respectively. The monthly injectable is a recommended contraceptive option for adolescents, especially for those facing psychosocial risk factors.

Determinants of climate change adaptation strategies used by fish farmers in Epe Local Government Area of Lagos State, Nigeria.

PubMed

Arimi, Kayode S

2014-05-01

Undesirable impacts of climate change have been a common occurrence that has made fish farmers in developing countries adopt some climate-change adaptation strategies. However, little is known about determinants of climate-change adaptation strategies used by these fish farmers. This study, therefore, articulates novelties on adaptation to climate change, as well ascertains determinants of adaptation strategies used by fish farmers in Epe, Lagos State, Nigeria. Climate change adaptation strategies mostly used by fish farmers include frequent seeking for early warning information about climate change (76.7%) and avoidance of areas susceptible to flooding (60.0%). Climate-change adaptation strategies used by fish farmers were significantly influenced by access to early warning information (β = 7.21), knowledge of farmers about climate change adaptation strategies (β = 8.86), access to capital (β = 28.25), and participation in workshop and conferences (β = 37.19) but were reduced by number of fish stocking (β = -2.06). The adaptation strategies used by fish farmers were autonomous and mostly determined by the access to credit facilities and information. Development policy should focus on carbon capture and storage technology in order to reduce adverse impacts of climate change, as well as making early warning information on climate change available to fish farmers. These will enhance adaptation to climate change. © 2013 Society of Chemical Industry.

Structure Characterization and Catalytic Properties of Cr2O3 Doped with MgO Supported on MgF2

NASA Astrophysics Data System (ADS)

Goslar, J.; Wojciechowska, M.; Zieliński, M.; Tomska-Foralewska, I.; Przystajko, W.

2006-08-01

A characterization of double oxide systems containing Cr2O3 doped with MgO and supported on MgF2 was carried out. The catalysts were prepared by impregnation and co-impregnation methods and characterized by the Brunauer-Emmett-Teller method, EPR, and temperature programmed reduction. The results proved the interactions between supported oxides and the presence of spinel-like phase after treatment at 400 ºC. Magnesium oxide clearly influences the catalytic activity as well as selectivity of chromium catalysts supported on MgF2. The MgO-Cr2O3/MgF2 systems were active and selective in the reaction of CO oxidation at the room temperature and in the dehydrogenation of cyclohexene.

Speciation of Mg in biogenic calcium carbonates

NASA Astrophysics Data System (ADS)

Farges, F.; Meibom, A.; Flank, A.-M.; Lagarde, P.; Janousch, M.; Stolarski, J.

2009-11-01

A selection of marine biominerals, mostly aragonitic coral skeletons were probed at the Mg K-edge by XANES spectroscopy coupled to μXRF methods and compared to an extensive set of relevant model compounds (silicates, carbonates, oxides and organic). Extensive methodologies are required to better describe the speciation of Mg in those minerals. A combination of ab-initio XANES calculations for defective clusters around Mg in aragonite together with wavelets analyzes of the XANES region are required to robustly interpret the spectra. When using those methodologies, the speciation of Mg ranges from a magnesite-type environment in some scleractinian corals to an organic-type environment. In all environments, the Mg-domains probed appear to be less than 1 nm in size.

High prevalence of complementary and alternative medicine use among patients with sickle cell disease in a tertiary hospital in Lagos, South West, Nigeria.

PubMed

Busari, A A; Mufutau, M A

2017-06-07

Attention and interest in the use of complementary and alternative medicine (CAM) has been reignited globally, most especially in patients with chronic diseases. Sickle cell disease (SCD) is one of such chronic diseases associated with devastating clinical and psychosocial consequences, thus leading those affected to seek alternative treatment apart from orthodox medicine. Hence, this study aimed to determine the prevalence, pattern and tolerability of the use of CAM in patients with SCD in the Lagos University Teaching Hospital (LUTH). This was a cross-sectional survey of 200 respondents with SCD attending the hematology clinics of the Lagos University Teaching Hospital over a period of 3 months. Data on socio-demographic characteristic, clinical profile, the types and sources of CAM used were collected using a well structured pretested questionnaire. The data obtained were analyzed using Statistical Package for Social Sciences (SPSS®) version 17. Of the 200 patients who participated in the study, 113; 56.5% were males and 87; 43.5% were females. Majority of the SCD patients were 1-10 years old and their mean age was 18.8 ± 14.39 years. CAM was reportedly used by 88.5% of the respondents. Biological (herbal) products 156; 62.9% were the most commonly used CAM, followed by alternative medical systems 52; 20.9% and mind-body interventions 30; 12.1%. Relations, friends and neighbors influenced 85.2% of CAM users by recommending CAM to them. Tolerability of CAM was perceived to be excellent as only 33 (18.6%) of the respondents abandoned the use of CAM. Comparing CAM users and CAM non-users, there was no statistical significant difference in the proportion of those >18 years (45.76% vs 52.17%; p = 0.658), those who experienced two or more crises (51.41% vs 34.78%; p = 0.183), and those with stable haemoglobin concentration of >7 g/dL (15.81% vs 8.69%; p = 0.539) More patients among CAM non-users (91.30%) significantly spend over 3000 Naira (USD 15) per

Polybrominated diphenyl ethers and polychlorinated biphenyls in dust from cars, homes, and offices in Lagos, Nigeria.

PubMed

Harrad, Stuart; Abdallah, Mohamed Abou-Elwafa; Oluseyi, Temilola

2016-03-01

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in dust from 16 cars, 12 homes, and 18 offices in Lagos, Nigeria. These represent the first and second reports respectively of contamination of Nigerian indoor dust with these contaminants, and the second report on PCBs in car dust worldwide. Concentrations of BDE-47 and BDE-99 in two car dust samples (9300 and 3700 ng g(-1) for BDE-47 and 4200 and 19,000 ng g(-1) for BDE-99), are amongst the highest ever reported in car dust. ANOVA comparison with Canada, New Zealand, the UK, and the USA; reveals concentrations of BDEs-28, 49, 47, 66, 100, 99, 154, and 153 in Nigerian house dust, to be significantly lower than in Canada and the USA, with those of BDE-49 and 154 significantly lower than in New Zealand and the UK. Concentrations of BDE-209 in Nigeria were significantly lower than concentrations in the UK and the USA; while concentrations of PCB-180 were significantly greater than those in New Zealand, the UK, and the USA. Median concentrations of PCBs in cars were substantially higher than in the only previous study (in Kuwait and Pakistan). While median concentrations of PBDEs in cars generally exceeded those in homes, this was significant only for BDEs-49, 154, and 197, with concentrations in cars significantly greater than those in offices for BDEs-49 and 154. Contrastingly, concentrations of all target PCBs in offices exceeded significantly those in cars. This study underlines the truly global distribution of indoor contamination with PBDEs and PCBs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Layered double hydroxides as adsorbents and carriers of the herbicide (4-chloro-2-methylphenoxy)acetic acid (MCPA): systems Mg-Al, Mg-Fe and Mg-Al-Fe.

PubMed

Bruna, F; Celis, R; Pavlovic, I; Barriga, C; Cornejo, J; Ulibarri, M A

2009-09-15

Hydrotalcite-like compounds [Mg(3)Al(OH)(8)]Cl x 4H(2)O; [Mg(3)Fe(OH)(8)]Cl x 4H(2)O; [Mg(3)Al(0.5)Fe(0.5)(OH)(8)]Cl x 4H(2)O (LDHs) and calcined product of [Mg(3)Al(OH)(8)]Cl x 4H(2)O, Mg(3)AlO(4.5) (HT500), were studied as potential adsorbents of the herbicide MCPA [(4-chloro-2-methylphenoxy)acetic acid] as a function of pH, contact time and pesticide concentration, and also as support for the slow release of this pesticide, with the aim to reduce the hazardous effects that it can pose to the environment. The information obtained in the adsorption study was used for the preparation of LDH-MCPA complexes. The results showed high and rapid adsorption of MCPA on the adsorbents as well as that MCPA formulations based on LDHs and HT500 as pesticide supports displayed controlled release properties and reduced herbicide leaching in soil columns compared to a standard commercial MCPA formulation. Thereby, we conclude that the LDHs employed in this study can be used not only as adsorbents to remove MCPA from aqueous solutions, but also as supports for the slow release of this highly mobile herbicide, thus controlling its immediate availability and leaching.

Sexual behavior and the influencing factors among out of school female adolescents in Mushin market, Lagos, Nigeria.

PubMed

Odeyemi, Kofoworola; Onajole, Adebayo; Ogunowo, Babatunde

2009-01-01

High rates of adolescent pregnancy, sexually transmitted infections, and unsafe abortions in Nigeria indicate the need for a greater understanding of factors that affect adolescent sexuality. The sexual health needs of adolescents remain poorly known and addressed particularly among vulnerable subpopulations like out-of-school adolescents. The objective of this study was to examine the sexual behavior of female out-of-school adolescents and to identify factors that influence their sexual behavior. This cross-sectional study was conducted among a representative sample of unmarried, out-of-school female adolescents (n = 332, mean age 17 y), selected using cluster sampling, who were working in a major market (Mushin) in Lagos, Nigeria. Data were collected using interviewer administered questionnaires. Many girls (43.7%) have had sexual intercourse. The mean age at initiation was 16 years. The main reason for initiation was curiosity. Risky sexual behavior and transactional sex was common. Nonconsensual sex was also reported. Sexual health knowledge was poor, and friends served as their main source of information on sexual health issues. Factors associated with the initiation of sexual activity were friends sexual behavior, the person adolescents reside with, parents marital status, availability of funds to meet basic needs, and watching pornography (p < .05). Out-of-school female adolescents engaging in risky sexual behavior are exposed to sexual abuse, lack skills to resist pressure, and have limited access to credible reproductive health information. Appropriate interventions including provision of sexuality education and a supportive environment must be instituted to address their needs.

The role of HIV counselling and testing in sexual health behaviour change among undergraduates in Lagos, Nigeria.

PubMed

Wusu, Onipede; Okoukoni, Saturday

2011-01-01

In developing countries risky sexual behaviour among young people is on the increase. This study examined the likelihood of HIV counselling and testing (HCT) in reducing risky sexual behaviour among undergraduates in Lagos Metropolis in Nigeria. The main hypothesis tested in the study was the uptake of HCT is likely to reduce risky sexual behaviour among young undergraduates. A multistage sampling procedure was adopted to select a sample of 625 undergraduates in the study setting. A structured questionnaire was administered to respondents to elicit information on previous participation in HCT and sexual behaviour before and after participation. Result indicates that 26.1% of males and 28.9% of females ever participated in HCT. The average number of heterosexual partners kept by the respondents declined among males and females from 3.17 and 2.36, respectively before they participated in HCT to 2.27 and 1.6 after they participated in HCT. The differences in the average number of sexual partners by the respondents before and after they participated in HCT were statistically significant (P=0.000). The proportion of male respondents who engaged in frequent sex also declined from 35.8% (before participating in HCT) to 24.1% (after participating in HCT) and from 25% (before participating in HCT) to 24.7% (after participating in HCT) among females. In conclusion, participation in HCT is likely to reduce the prevalence of risky sexual behaviour among undergraduates in the study setting. Therefore, HCT is an intervention that should be emphasized.

High-resolution paleoclimate records of Holocene hydroclimatic variability in the Eastern Colombian Andes from Lago de Tota

NASA Astrophysics Data System (ADS)

Ahmed, M. N.; Bird, B. W.; Escobar, J.; Polissar, P. J.

2017-12-01

The Northern Hemisphere (NH) South American Monsoon (SAM) is a significant source of precipitation for the North Andes (north of 0˚) and has major control over regional hydroclimate variability. Holocene-length histories of NH SAM variability are few compared to the Southern Hemisphere (SH), limiting understanding of how these systems are connected on orbital and shorter timescales. Here, we present multi-proxy lake-sediment-based paleoclimate and paleohydrologic reconstructions from Lago de Tota, Colombia, using sedimentological, geochemical and leaf-wax hydrogen isotopic indicators from radiometically dated cores. The results indicate periods of wet and dry climate phases during the past 9000 BP with an average Holocene sedimentation rate 33cm/kyr. An increase in total organic matter (TOM) content and finer grain-size distributions was observed from 8000 to 3200 BP, suggesting a period of high lake level. This was followed by lower TOM and coarser grain sizes, suggesting lower lake levels from 3200 BP to the present. Although Tota's lake level pattern is antiphased with other lake level reconstructions from the NH and SH Andes, it is consistent with hypothesized changes in atmospheric convection over the Andes during the Holocene and the way in which they would be modified by the so-called dry island effect in the Colombian Andes. This suggests that a common forcing mechanism can be invoked to explain differing millennial-scale Andean hydroclimate changes, namely atmospheric convection. Orbital and Pacific atmosphere-forcing are therefore likely to have played a significant role in driving pan-Andean hydroclimate variability based on their inter-hemispheric influence on Andean convection.

The National Health Insurance Scheme (NHIS): a survey of knowledge and opinions of Nigerian dentists' in Lagos.

PubMed

Adeniyi, A A; Onajole, A T

2010-03-01

This study was designed to assess the knowledge and perceptions of Nigerian dentists to the National Health Insurance scheme (NHIS). A cross-sectional descriptive survey was conducted amongst 250 dentists employed in private and public dental clinics in Lagos State, Nigeria. The survey instrument was a self-administered questionnaire designed to assess their knowledge and attitudes towards the scheme. Data analysis was done using the Epi-Info statistical software (version 6.04). Statistical tools used included measures of central tendency, frequency distribution and chi-square test. A total of 216 dentists (response rate of 82.4%) participated in this study. Most 132 (61.1%) of the respondents had a fair knowledge of the NHIS, while 22 (10.2%) and 62 (28.7%) had poor and good knowledge respectively. Majority (70.4%) viewed the NHIS as a good idea that will succeed if properly implemented. Most (76.6%) respondents also believed that the scheme will improve access to oral health services, affordability of services (71.4%), availability of the services (68.3%) and recognition of dentistry as a profession (62.4%). Most of the respondents (66.2%) considered oral health care as not properly positioned in the NHIS and 154 respondents (74.4%) found the current position of oral health on the NHIS unacceptable. A good number of the respondents (77.3%) would like dentistry to operate at the primary care level on the NHIS. Majority of the dentists involved in this study had some knowledge of the NHIS and were generally positively disposed towards the scheme and viewed it as a good idea.

Ca Addition Effects on the Microstructure, Tensile and Corrosion Properties of Mg Matrix Alloy Containing 8 wt.% Mg2Si

NASA Astrophysics Data System (ADS)

Lotfpour, M.; Emamy, M.; Dehghanian, C.; Pourbahari, B.

2018-02-01

The microstructure, tensile properties and corrosion behavior of the Mg-8 wt.% Mg2Si-x%Ca alloy have been studied by the use of optical microscopy, scanning electron microscopy equipped with energy-dispersive spectroscopy, x-ray diffraction, standard tensile testing, polarization test and electrochemical impedance spectroscopy (EIS) measurements. Microstructural studies indicated that Ca modifies both primary and eutectic Mg2Si phase. It was found that the average size of primary Mg2Si particles is about 60 μm, which is dropped by about 82% in the alloy containing 0.05 wt.% Ca. By the addition of different Ca contents, Ca-rich intermetallics (i.e., CaSi2 and CaMgSi) were formed. The modification mechanism of adding Ca during solidification was found to be due to the strong effect of CaMgSi phase as a heterogonous nucleation site, apart from CaSi2 which was reported before, for Mg2Si intermetallics. Tensile testing results ascertained that Ca addition enhances both ultimate tensile strength (UTS) and elongation values. The optimum amount of Ca was found to be 0.1 wt.%, which improved UTS and elongation values from about 130 MPa and 2% to 165 MPa and 5.5%, whereas more Ca addition (i.e., 3 wt.%) reduced the tensile properties of the alloy to about 105 MPa and 1.8%, which can be due to the formation of CaMgSi intermetallics with deteriorating needle-like morphology. Polarization and EIS tests also showed that the Mg-3%Si-0.5%Ca alloy pronounces as the best anti-corrosion alloy. Nevertheless, further added Ca (up to 3 wt.%) deteriorated the corrosion resistance due to predominance of worse galvanic coupling effect stemmed from the presence of stronger CaMgSi cathode in comparison with Mg2Si. With higher Ca additions, an adverse effect was seen on corrosion resistance of the Mg-3%Si alloy, as a result of forming a weak film on the alloy specimen surface.

Pinning in high performance MgB2 thin films and bulks: Role of Mg-B-O nano-scale inhomogeneities

NASA Astrophysics Data System (ADS)

Prikhna, Tatiana; Shapovalov, Andrey; Eisterer, Michael; Shaternik, Vladimir; Goldacker, Wilfried; Weber, Harald W.; Moshchil, Viktor; Kozyrev, Artem; Sverdun, Vladimir; Boutko, Viktor; Grechnev, Gennadiy; Gusev, Alexandr; Kovylaev, Valeriy; Shaternik, Anton

2017-02-01

The comparison of nano-crystalline MgB2 oxygen-containing thin film (140 nm) and highly dense bulk materials showed that the critical current density, Jc, depends on the distribution of Mg-B-O nano-scale inhomogeneities. It has been shown that MgB2 bulks with high Jc in low (∼106 A/cm2 in 0-1 T at 10 K) and medium magnetic fields contain MgB0.6-0.8O0.8-0.9 nano-inclusions, where δTc or a combined δTc (dominant) / δl pinning mechanism prevails, while in bulk MgB2 with high Jc in high magnetic fields (Birr(18.5 K) = 15 T, Bc2(0 K) = 42.1 T) MgB1.2-2.7O1.8-2.5 nano-layers are present and δl pinning prevails. The structure of oxygen-containing films with high Jc in low and high magnetic fields (Jc (0 Т) = 1.8 × 107 А/сm2 and Jc (5 Т) = 2 × 106 А/сm2 at 10 К) contains very fine oxygen-enriched Mg-B-O inhomogeneities and δl pinning is realized. The results of DOS calculations in MgB2-xOx cells for x = 0, 0.125, 0.25, 0.5, 1 demonstrate that all compounds are conductors with metal-like behaviour. In the case of ordered oxygen substitution for boron the binding energy, Eb, does not increase sufficiently as compared with that for MgB2, while when oxygen atoms form zigzag chains the calculated Eb is even lower (Eb = -1.15712 Ry).

Computational prediction of Mg-isotope fractionation between aqueous [Mg(OH2)6]2+ and brucite

NASA Astrophysics Data System (ADS)

Colla, Christopher A.; Casey, William H.; Ohlin, C. André

2018-04-01

The fractionation factor in the magnesium-isotope fractionation between aqueous solutions of magnesium and brucite changes sign with increasing temperature, as uncovered by recent experiments. To understand this behavior, the Reduced Partition Function Ratios and isotopic fractionation factors (Δ26/24Mgbrucite-Mg(aq)) are calculated using molecular models of aqueous [Mg(OH2)6]2+ and the mineral brucite at increasing levels of density functional theory. The calculations were carried out on the [Mg(OH2)6]2+·12H2O cluster, along with different Pauling-bond-strength-conserving models of the mineral lattice of brucite. Three conclusions were reached: (i) all levels of theory overestimate bond distances in the aqua ion complex relative to Tutton's salts; (ii) the calculations predict that brucite at 298.15 K is always enriched in the heavy isotope, in contrast with experimental observations; (iii) the temperature dependencies of Wimpenny et al. (2014) and Li et al. (2014) could only be achieved by fixing the bond distances in the [Mg(OH2)6]2+·12H2O cluster to values close to those observed in crystals that trap the hydrated ion.

Enhanced corrosion resistance and cytocompatibility of biodegradable Mg alloys by introduction of Mg(OH)2 particles into poly (L-lactic acid) coating

PubMed Central

Shi, Yong-juan; Pei, Jia; Zhang, Jian; Niu, Jia-lin; Zhang, Hua; Guo, Sheng-rong; Li, Zhong-hua; Yuan, Guang-yin

2017-01-01

A strategy of suppressing the fast degradation behaviour of Mg-based biomaterials by the introduction of one of Mg degradation products Mg(OH)2 was proposed according to the following degradation mechanism, Mg + 2H2O ⇋ Mg(OH)2 + H2↑. Specifically, Mg(OH)2 submicron particles were mixed into poly (L-lactic acid) (PLLA) to synthesize a composite coating onto hydrofluoric acid-pretreated Mg-Nd-Zn-Zr alloy. The in vitro degradation investigations showed that the addition of Mg(OH)2 particles not only slowed down the corrosion of Mg matrix, but also retarded the formation of gas pockets underneath the polymer coating. Correspondingly, cytocompatibility results exhibited significant improvement of proliferation of endothelial cells, and further insights was gained into the mechanisms how the introduction of Mg(OH)2 particles into PLLA coating affected the magnesium alloy degradation and cytocompatibility. The present study provided a promising surface modification strategy to tailor the degradation behaviour of Mg-based biomaterials. PMID:28150751

Cathodoluminescence study of Mg activation in non-polar and semi-polar faces of undoped/Mg-doped GaN core-shell nanorods.

PubMed

Hortelano, V; Martínez, O; Cuscó, R; Artús, L; Jiménez, J

2016-03-04

Spectrally and spatially resolved cathodoluminescence (CL) measurements were carried out at 80 K on undoped/Mg-doped GaN core-shell nanorods grown by selective area growth metalorganic vapor phase epitaxy in order to investigate locally the optical activity of the Mg dopants. A study of the luminescence emission distribution over the different regions of the nanorods is presented. We have investigated the CL fingerprints of the Mg incorporation into the non-polar lateral prismatic facets and the semi-polar facets of the pyramidal tips. The amount of Mg incorporation/activation was varied by using several Mg/Ga flow ratios and post-growth annealing treatment. For lower Mg/Ga flow ratios, the annealed nanorods clearly display a donor-acceptor pair band emission peaking at 3.26-3.27 eV and up to 4 LO phonon replicas, which can be considered as a reliable indicator of effective p-type Mg doping in the nanorod shell. For higher Mg/Ga flow ratios, a substantial enhancement of the yellow luminescence emission as well as several emission subbands are observed, which suggests an increase of disorder and the presence of defects as a consequence of the excess Mg doping.

Cathodoluminescence study of Mg activation in non-polar and semi-polar faces of undoped/Mg-doped GaN core-shell nanorods

NASA Astrophysics Data System (ADS)

Hortelano, V.; Martínez, O.; Cuscó, R.; Artús, L.; Jiménez, J.

2016-03-01

Spectrally and spatially resolved cathodoluminescence (CL) measurements were carried out at 80 K on undoped/Mg-doped GaN core-shell nanorods grown by selective area growth metalorganic vapor phase epitaxy in order to investigate locally the optical activity of the Mg dopants. A study of the luminescence emission distribution over the different regions of the nanorods is presented. We have investigated the CL fingerprints of the Mg incorporation into the non-polar lateral prismatic facets and the semi-polar facets of the pyramidal tips. The amount of Mg incorporation/activation was varied by using several Mg/Ga flow ratios and post-growth annealing treatment. For lower Mg/Ga flow ratios, the annealed nanorods clearly display a donor-acceptor pair band emission peaking at 3.26-3.27 eV and up to 4 LO phonon replicas, which can be considered as a reliable indicator of effective p-type Mg doping in the nanorod shell. For higher Mg/Ga flow ratios, a substantial enhancement of the yellow luminescence emission as well as several emission subbands are observed, which suggests an increase of disorder and the presence of defects as a consequence of the excess Mg doping.

Electrochemical Formation of Mg-Li-Sm Alloys by Codeposition from LiCl-KCl-MgCl2-SmCl3 Molten Salts

NASA Astrophysics Data System (ADS)

Han, Wei; Wang, Fengli; Tian, Yang; Zhang, Milin; Yan, Yongde

2011-12-01

In this article, the electrochemical method of preparing Mg-Li-Sm alloys by codeposition in LiCl-KCl-MgCl2-SmCl3 melts was investigated. Transient electrochemical techniques, such as cyclic voltammetry, chronopotentiometry, and chronoamperometry were used to explore the electrochemical formation of Mg-Li-Sm alloys. Chronopotentiograms demonstrated that the codepositon of Mg, Li, and Sm occurred when current densities were more negative than -0.31 A cm-2. Chronoamperograms indicated that the onset potential for the codeposition of Mg, Li, and Sm was -2.40 V, and the codeposition of Mg, Li, and Sm was formed when the applied potentials were more negative than -2.40 V. The different phases of Mg-Li-Sm alloys were prepared by galvanostatic electrolysis and characterized by X-ray diffraction (XRD), optical microscope (OM), and scanning electron microscopy (SEM). An inductively coupled plasma (ICP) analysis showed that the lithium and samarium contents in Mg-Li-Sm alloys could be controlled by the concentrations of MgCl2 and SmCl3. The results demonstrated that Sm could refine the grains dramatically. When the Sm content was 0.8 wt pct, the grain size was the finest.

Hydrogen storage and phase transformations in Mg-Pd nanoparticles

NASA Astrophysics Data System (ADS)

Callini, E.; Pasquini, L.; Rude, L. H.; Nielsen, T. K.; Jensen, T. R.; Bonetti, E.

2010-10-01

Microstructure refinement and synergic coupling among different phases are currently explored strategies to improve the hydrogen storage properties of traditional materials. In this work, we apply a combination of these methods and synthesize Mg-Pd composite nanoparticles by inert gas condensation of Mg vapors followed by vacuum evaporation of Pd clusters. Irreversible formation of the Mg6Pd intermetallic phase takes place upon vacuum annealing, resulting in Mg/Mg6Pd composite nanoparticles. Their hydrogen storage properties are investigated and connected to the undergoing phase transformations by gas-volumetric techniques and in situ synchrotron radiation powder x-ray diffraction. Mg6Pd transforms reversibly into different Mg-Pd intermetallic compounds upon hydrogen absorption, depending on temperature and pressure. In particular, at 573 K and 1 MPa hydrogen pressure, the metal-hydride transition leads to the formation of Mg3Pd and Mg5Pd2 phases. By increasing the pressure to 5 MPa, the Pd-richer MgPd intermetallic is obtained. Upon hydrogen desorption, the Mg6Pd phase is reversibly recovered. These phase transformations result in a specific hydrogen storage capacity associated with Mg-Pd intermetallics, which attain the maximum value of 3.96 wt % for MgPd and influence both the thermodynamics and kinetics of hydrogen sorption in the composite nanoparticles.

Comparison of the effects of esomeprazole 40 mg, rabeprazole 20 mg, lansoprazole 30 mg, and pantoprazole 40 mg on intragastrıc pH in extensive metabolizer patients with gastroesophageal reflux disease.

PubMed

Çelebi, Altay; Aydın, Dinçer; Kocaman, Orhan; Konduk, Buğra Tolga; Şentürk, Ömer; Hülagü, Sadetin

2016-09-01

Studies on the therapeutic efficacy of proton pump inhibitors (PPIs) in patients with gastroesophageal reflux disease (GERD) have been recently published. In most of these studies, comparison of only two PPIs have been made. There are few studies on the comparison of four or more PPIs. We aimed to compare the acid inhibitory effects of esomeprazole 40 mg, rabeprazole 20 mg, lansoprazole 30 mg, and pantoprazole 40 mg on days 1 and 5 of treatment in patients with GERD, who were extensive metabolizers in regard to the CYP2C19 genotype. Helicobacter pylori-negative with typical symptoms of GERD patients were randomly divided into four treatment groups. Efficacy analysis on days 1 and 5 were performed on the four groups which comprised 10 (esomeprazole), 11 (rabeprazole), 10 (lansoprazole), and 10 (pantoprazole) patients. On day 1 of PPI treatment, the mean percentage of time with intragastric Ph>4 were 54%, 58%, 60%, and 35% for the groups, respectively, and on day 5, these values were 67%, 60%, 68%, and 59%, respectively. Esomeprazole, rabeprazole, and lansoprazole were found to be superior to pantoprazole on the first day of treatment. Pantoprazole is a less potent proton pump inhibitor than the other PPIs tested on the first day of treatment. When the time needed to raise the intragatric pH to over 4 was evaluated, esomeprazole was found to have the most rapid action, followed by lansoprazole and rabeprazole.

Mechanisms for monovalent cation-dependent depletion of intracellular Mg2+:Na(+)-independent Mg2+ pathways in guinea-pig smooth muscle.

PubMed

Nakayama, Shinsuke; Nomura, Hideki; Smith, Lorraine M; Clark, Joseph F; Uetani, Tadayuki; Matsubara, Tatsuaki

2003-09-15

It has been suggested that magnesium deficiency is correlated with many diseases. 31P NMR experiments were carried out in order to investigate the effects of Na+ substitution on Mg2+ depletion in smooth muscle under divalent cation-free conditions. In the taenia of guinea-pig caeci, the intracellular free Mg2+ concentration ([Mg2+]i) was estimated from the chemical shifts of (1) the beta-ATP peak alone and (2) beta- and gamma-ATP peaks. Both estimations indicated that [Mg2+]i decreased only very slowly in Mg(2+)-free, Ca(2+)-free solutions in which Na+ was substituted with large cations such as NMDG (N-methyl-D-glucamine) and choline. Furthermore, the measurements of tension development supported the suggestion of preservation of intracellular Mg2+ with NMDG substitution. Substituting extracellular Na+ with the small cation, Li+, also shifted the beta-ATP peak towards a lower frequency, but the frequency shift was significantly less than that seen upon Na+ substitution with K+. The estimated [Mg2+]i depletion was, however, comparable with that seen after Na+ substitution with K+ using the titration curves of metal-free and Mg(2+)-bound ATP obtained in Li(+)-based model solutions. It was concluded that Mg2+ rapidly decreases only when small cations were the major electrolyte of the extracellular medium. Na+ substitutions with NMDG, choline or Li+ had little effect on intracellular ATP concentration after 100 min treatment.

Role of chemical interaction between MgH2 and TiO2 additive on the hydrogen storage behavior of MgH2

NASA Astrophysics Data System (ADS)

Pukazhselvan, D.; Nasani, Narendar; Sandhya, K. S.; Singh, Budhendra; Bdikin, Igor; Koga, Nobuaki; Fagg, Duncan Paul

2017-10-01

The present study explores how the additive titania chemically reacts with magnesium hydride and influences the dehydrogenation of MgH2. Quantitative X - ray diffraction study of ball milled MgH2 + xTiO2 (x = 0.25, 0.33, 0.5 and 1) suggests that Ti substituted MgO is the main reaction product in all the product powders. Convincing evidence is obtained to conclude that Ti dissolution in MgO makes a dramatic behavioral change to MgO; passive MgO turns as an active in-built catalyst. The analysis correlating the dehydrogenation kinetics, composition of in-situ catalyst and sample durability suggests that effectiveness of Ti substituted MgO (MgxTiyOx+y) as a catalyst for MgH2 depends on the concentration of Ti in MgxTiyOx+y rock salt. These observations are immensely helpful for understanding the hydrogen desorption mechanism of metal oxide additives loaded MgH2 system.

Thermodynamics and Kinetics of Three Mg-H-VN Complexes in Mg:GaN from Combined First-Principles Calculation and Experiment

NASA Astrophysics Data System (ADS)

Lee, Donghwa; Mitchell, Brandon; Fujiwara, Y.; Dierolf, V.

2014-05-01

An understanding of the formation and dissociation process of Mg-H defects in GaN is of paramount importance for high efficient GaN-based solid-state lighting. Through a combination of first-principle calculations and experimental observations, we find the existence of three types of Mg related centers forming different Mg-H-VN complexes in Mg:GaN. Our study shows that the three different arrangements, which differ by the relative position of the H, determine the degree of acceptor passivation by changing their charge state from +3 to +1. The energetic study demonstrates that the relative stability of the defect complexes can vary with the location of the Fermi level, as well as thermal annealing and electron beam irradiation. The inclusion of a VN is shown to produce an additional variance in optical spectra associated with Mg acceptor activation, resulting from changes in the defect configurations and charge states. Our study shows that these three Mg-H-VN complexes are key components for understanding the Mg acceptor activation and passivation processes.

A comparison of amorphous calcium carbonate crystallization in aqueous solutions of MgCl2 and MgSO4: implications for paleo-ocean chemistry

NASA Astrophysics Data System (ADS)

Han, Mei; Zhao, Yanyang; Zhao, Hui; Han, Zuozhen; Yan, Huaxiao; Sun, Bin; Meng, Ruirui; Zhuang, Dingxiang; Li, Dan; Liu, Binwei

2018-04-01

Based on the terminology of "aragonite seas" and "calcite seas", whether different Mg sources could affect the mineralogy of carbonate sediments at the same Mg/Ca ratio was explored, which was expected to provide a qualitative assessment of the chemistry of the paleo-ocean. In this work, amorphous calcium carbonate (ACC) was prepared by direct precipitation in anhydrous ethanol and used as a precursor to study crystallization processes in MgSO4 and MgCl2 solutions having different concentrations at 60 °C (reaction times 240 and 2880 min). Based on the morphology of the aragonite crystals, as well as mineral saturation indices and kinetic analysis of geochemical processes, it was found that these crystals formed with a spherulitic texture in 4 steps. First, ACC crystallized into columnar Mg calcite by nearly oriented attachment. Second, the Mg calcite changed from columnar shapes into smooth dumbbell forms. Third, the Mg calcite transformed into rough dumbbell or cauliflower-shaped aragonite forms by local dissolution and precipitation. Finally, the aragonite transformed further into spherulitic radial and irregular aggregate forms. The increase in Ca2+ in the MgSO4 solutions compared with the MgCl2 solutions indicates the fast dissolution and slow precipitation of ACC in the former solutions. The phase transition was more complete in the 0.005 M MgCl2 solution, whereas Mg calcite crystallized from the 0.005 M MgSO4 solution, indicating that Mg calcite could be formed more easily in an MgSO4 solution. Based on these findings, aragonite and Mg calcite relative to ACC could be used to provide a qualitative assessment of the chemistry of the paleo-ocean. Therefore, calcite seas relative to high-Mg calcite could reflect a low concentration MgSO4 paleo-ocean, while aragonite seas could be related to an MgCl2 or high concentration of MgSO4 paleo-ocean.

Interdiffusion and Intrinsic Diffusion in the Mg-Al System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brennan, Sarah; Bermudez, Katrina; Sohn, Yong Ho

2012-01-01

Solid-to-solid diffusion couples were assembled and annealed to examine the diffusion between pure Mg (99.96%) and Al (99.999%). Diffusion anneals were carried out at 300 , 350 , and 400 C for 720, 360, and 240 hours, respectively. Optical and scanning electron microscopes were utilized to identify the formation of the intermetallic phases, -Al12Mg17 and -Al3Mg2 and absence of the -phase in the diffusion couples. Thicknesses of the -Al12Mg17 and -Al3Mg2 phases were measured and the parabolic growth constants were calculated to determine the activation energies for the growth, 165 and 86 KJ/mole, respectively. Concentration profiles were determined with electronmore » microprobe analysis using pure elemental standards. Composition-dependent interdiffusion coefficients in Mg-solid solution, -Al12Mg17 and - Al3Mg2 and Al-solid solutions were calculated based on the Boltzmann-Matano analysis. Average effective interdiffusion coefficients for each phase were also calculated, and the magnitude was the highest for the -Al3Mg2 phase, followed by -Al12Mg17, Al-solid solution and Mg-solid solution. Intrinsic diffusion coefficients based on Huemann s analysis (e.g., marker plane) were determined for the ~38 at.% Mg in the -Al3Mg2 phase. Activation energies and the pre-exponential factors for the inter- and intrinsic diffusion coefficients were calculated for the temperature range examined. The -Al3Mg2 phase was found to have the lowest activation energies for growth and interdiffusion among all four phases studied. At the marker location in the -Al3Mg2 phase, the intrinsic diffusion of Al was found to be faster than that of Mg. Extrapolations of the impurity diffusion coefficients in the terminal solid solutions were made and compared to the available self- and impurity diffusion data from literature. Thermodynamic factor, tracer diffusion coefficients and atomic mobilities at the marker plane composition were approximated using available literature values of Mg activity in

Clinical acceptability study of micronized purified flavonoid fraction 1000 mg tablets versus 500 mg tablets in patients suffering acute hemorrhoidal disease.

PubMed

Shelygin, Yuri; Krivokapic, Zoran; Frolov, S A; Kostarev, I V; Astashov, V L; Vasiliev, S V; Lakhin, A V; Rodoman, G V; Soloviev, A O; Stoyko, Y M; Khitaryan, A G; Nechay, I A

2016-11-01

To compare the clinical acceptability of micronized purified flavonoid fraction (MPFF) 1000 mg with MPFF 500 mg tablets, administered at the same daily dose in patients suffering non-complicated acute hemorrhoids. MPFF is an established treatment for hemorrhoidal disease. This was a double-blind, multi-center, randomized study. Patients took either MPFF 1000 mg or 500 mg tablets for 7 days (daily dose; 3 g over 4 days followed by 2 g over 3 days). Adverse events were recorded in a patient diary. On day 7, anal pain and bleeding were assessed (visual analog scale [VAS] and Dimitroulopoulos scale, respectively). Patients (162) were randomized to MPFF 1000 mg (79) and MPFF 500 mg (83). No serious adverse events (AEs) occurred; 10 emergent AEs were considered treatment-related (6 for MPFF 1000 mg and 4 for 500 mg). Both regimens were associated with significant reduction in anal pain (VAS); -2.37 cm MPFF 1000 mg (P < 0.001) and -2.17 cm 500 mg (P < 0.001), with a slight trend in favor of MPFF 1000 mg (mean global reduction -2.27 cm, P < 0.001). Bleeding improved significantly in both groups of patients, 56% of patients on MPFF 1000 mg versus 61% on MPFF 500 mg. Bleeding ceased after treatment in 47% patients on MPFF 1000 mg versus 54% on 500 mg. After 7 days of treatment with MPFF at the same daily dose, both regimens reduced anal pain and bleeding. MPFF 1000 mg had a comparable safety profile to MPFF 500 mg, with the advantage of fewer tablets. Key limitations: Safety study.

Birth plans and health insurance enrolment of pregnant women: a cross-sectional survey at two secondary health facilities in Lagos, Nigeria.

PubMed

Okusanya, Babasola O; Roberts, Alero A; Akinsola, Oluwatosin J; Oye-Adeniran, Boniface A

2016-01-01

We evaluated birth plans and health insurance enrolment of pregnant women at secondary health care level as a strategy for post-2015 goals. This was a cross-sectional study at two secondary health facilities in Lagos state, Nigeria. A pre-tested questionnaire was used to collect data that were analysed and results presented with frequencies. An overall estimate with 95% confidence interval was used at significant p values of less than 0.05. Five hundred and twenty-four women, with a mean age of 3 0 ± 4.1 years, participated. Most women chose hospital delivery (84%) and had plan for transportation (86.3%) during labour. Few women were well prepared for birth (9.7%) and had health insurance (10.1%). Compared with women without insurance, more health-insured women had plans for transport in labour (p = 0.1383) and identified a place of birth (p = 0.2294), but did not have as much plan for someone to accompany them in the case of an emergency (p = 0.3855) and donate blood (p = 0.5065). Few health insured women saved money for delivery (p = 0.7439). Health insured women did not have better birth plans and expanding pregnant women's access to health insurance may be an insufficient strategy to achieve post MDG 2015 goals.

Kinematics of syn- and post-exhumational shear zones at Lago di Cignana (Western Alps, Italy): constraints on the exhumation of Zermatt-Saas (ultra)high-pressure rocks and deformation along the Combin Fault and Dent Blanche Basal Thrust

NASA Astrophysics Data System (ADS)

Kirst, Frederik; Leiss, Bernd

2017-01-01

Kinematic analyses of shear zones at Lago di Cignana in the Italian Western Alps were used to constrain the structural evolution of units from the Piemont-Ligurian oceanic realm (Zermatt-Saas and Combin zones) and the Adriatic continental margin (Dent Blanche nappe) during Palaeogene syn- and post-exhumational deformation. Exhumation of Zermatt-Saas (U)HP rocks to approximately lower crustal levels at ca. 39 Ma occurred during normal-sense top-(S)E shearing under epidote-amphibolite-facies conditions. Juxtaposition with the overlying Combin zone along the Combin Fault at mid-crustal levels occurred during greenschist-facies normal-sense top-SE shearing at ca. 38 Ma. The scarcity of top-SE kinematic indicators in the hanging wall of the Combin Fault probably resulted from strain localization along the uppermost Zermatt-Saas zone and obliteration by subsequent deformation. A phase of dominant pure shear deformation around 35 Ma affected units in the direct footwall and hanging wall of the Combin Fault. It is interpreted to reflect NW-SE crustal elongation during updoming of the nappe stack as a result of underthrusting of European continental margin units and the onset of continental collision. This phase was partly accompanied and followed by ductile bulk top-NW shearing, especially at higher structural levels, which transitioned into semi-ductile to brittle normal-sense top-NW deformation due to Vanzone phase folding from ca. 32 Ma onwards. Our structural observations suggest that syn-exhumational deformation is partly preserved within units and shear zones exposed at Lago di Cignana but also that the Combin Fault and Dent Blanche Basal Thrust experienced significant post-exhumational deformation reworking and overprinting earlier structures.

Comparison of 1 mg and 2 mg overnight dexamethasone suppression tests for the screening of Cushing's syndrome in obese patients.

PubMed

Sahin, Mustafa; Kebapcilar, Levent; Taslipinar, Abdullah; Azal, Omer; Ozgurtas, Taner; Corakci, Ahmet; Akgul, Emin Ozgur; Taslipinar, Mine Yavuz; Yazici, Mahmut; Kutlu, Mustafa

2009-01-01

Obesity is currently a major public health problem and one of the potential underlying causes of obesity in a minority of patients is Cushing's syndrome (CS). Traditionally, the gold standard screening test for CS is 1 mg dexamethasone overnight suppression test. However, it is known that obese subjects have high false positive results with this test. We have therefore compared the 1 mg and 2 mg overnight dexamethasone suppression tests in obese subjects. Patients whose serum cortisol after ODST was >50 nM underwent and a low-dose dexamethasone suppression test (LDDST); 24-hour urine cortisol was collected for basal urinary free cortisol (UFC). For positive results after overnight 1-mg dexamethasone suppression test we also performed the overnight 2-mg dexamethasone suppression test. We prospectively evaluated 100 patients (22 men and 78 women, ranging in age from 17 to 73 years with a body mass index (BMI) >30 kg/m2 who had been referred to our hospital-affiliated endocrine clinic because of simple obesity. Suppression of serum cortisol to <50 nM (1.8 microg/dL) after dexamethasone administration was chosen as the cut-off point for normal suppression. Thyroid function tests, lipid profiles, homocysteine, antithyroglobulin, anti-thyroid peroxidase antibody levels, vitamin B12, folate levels, insulin resistance [by homeostasis model assessment (HOMA)] and 1.0 mg postdexamethasone (postdex) suppression cortisol levels were measured. We found an 8% false-positive rate in 1 mg overnight test and 2% in 2 mg overnight test (p=0.001). There was no correlation between the cortisol levels after ODST and other parameters. Our results indicate that the 2 mg overnight dexamethasone suppression test (ODST) is more convenient and accurate than 1-mg ODST as a screening test for excluding CS in subjects with simple obesity.

Interplay of Mg2+, ADP, and ATP in the cytosol and mitochondria: Unravelling the role of Mg2+ in cell respiration

PubMed Central

Gout, Elisabeth; Rébeillé, Fabrice; Douce, Roland; Bligny, Richard

2014-01-01

In animal and plant cells, the ATP/ADP ratio and/or energy charge are generally considered key parameters regulating metabolism and respiration. The major alternative issue of whether the cytosolic and mitochondrial concentrations of ADP and ATP directly mediate cell respiration remains unclear, however. In addition, because only free nucleotides are exchanged by the mitochondrial ADP/ATP carrier, whereas MgADP is the substrate of ATP synthase (EC 3.6.3.14), the cytosolic and mitochondrial Mg2+ concentrations must be considered as well. Here we developed in vivo/in vitro techniques using 31P-NMR spectroscopy to simultaneously measure these key components in subcellular compartments. We show that heterotrophic sycamore (Acer pseudoplatanus L.) cells incubated in various nutrient media contain low, stable cytosolic ADP and Mg2+ concentrations, unlike ATP. ADP is mainly free in the cytosol, but complexed by Mg2+ in the mitochondrial matrix, where [Mg2+] is tenfold higher. In contrast, owing to a much higher affinity for Mg2+, ATP is mostly complexed by Mg2+ in both compartments. Mg2+ starvation used to alter cytosolic and mitochondrial [Mg2+] reversibly increases free nucleotide concentration in the cytosol and matrix, enhances ADP at the expense of ATP, decreases coupled respiration, and stops cell growth. We conclude that the cytosolic ADP concentration, and not ATP, ATP/ADP ratio, or energy charge, controls the respiration of plant cells. The Mg2+ concentration, remarkably constant and low in the cytosol and tenfold higher in the matrix, mediates ADP/ATP exchange between the cytosol and matrix, [MgADP]-dependent mitochondrial ATP synthase activity, and cytosolic free ADP homeostasis. PMID:25313036

Interplay of Mg2+, ADP, and ATP in the cytosol and mitochondria: unravelling the role of Mg2+ in cell respiration.

PubMed

Gout, Elisabeth; Rébeillé, Fabrice; Douce, Roland; Bligny, Richard

2014-10-28

In animal and plant cells, the ATP/ADP ratio and/or energy charge are generally considered key parameters regulating metabolism and respiration. The major alternative issue of whether the cytosolic and mitochondrial concentrations of ADP and ATP directly mediate cell respiration remains unclear, however. In addition, because only free nucleotides are exchanged by the mitochondrial ADP/ATP carrier, whereas MgADP is the substrate of ATP synthase (EC 3.6.3.14), the cytosolic and mitochondrial Mg(2+) concentrations must be considered as well. Here we developed in vivo/in vitro techniques using (31)P-NMR spectroscopy to simultaneously measure these key components in subcellular compartments. We show that heterotrophic sycamore (Acer pseudoplatanus L.) cells incubated in various nutrient media contain low, stable cytosolic ADP and Mg(2+) concentrations, unlike ATP. ADP is mainly free in the cytosol, but complexed by Mg(2+) in the mitochondrial matrix, where [Mg(2+)] is tenfold higher. In contrast, owing to a much higher affinity for Mg(2+), ATP is mostly complexed by Mg(2+) in both compartments. Mg(2+) starvation used to alter cytosolic and mitochondrial [Mg(2+)] reversibly increases free nucleotide concentration in the cytosol and matrix, enhances ADP at the expense of ATP, decreases coupled respiration, and stops cell growth. We conclude that the cytosolic ADP concentration, and not ATP, ATP/ADP ratio, or energy charge, controls the respiration of plant cells. The Mg(2+) concentration, remarkably constant and low in the cytosol and tenfold higher in the matrix, mediates ADP/ATP exchange between the cytosol and matrix, [MgADP]-dependent mitochondrial ATP synthase activity, and cytosolic free ADP homeostasis.

Mg2Sn heterostructures on Si(111) substrate

NASA Astrophysics Data System (ADS)

Dózsa, L.; Galkin, N. G.; Pécz, B.; Osváth, Z.; Zolnai, Zs.; Németh, A.; Galkin, K. N.; Chernev, I. M.; Dotsenko, S. A.

2017-05-01

Thin un-doped and Al doped polycrystalline Mg-stannide films consisting mainly of Mg2Sn semiconductor phase have been grown by deposition of Sn-Mg multilayers on Si(111) p-type wafers at room temperature and annealing at 150 °C. Rutherford backscattering measurement spectroscopy (RBS) were used to determine the amount of Mg and Sn in the structures. Raman spectroscopy has shown the layers contain Mg2Sn phase. Cross sectional transmission electron microscopy (XTEM) measurements have identified Mg2Sn nanocrystallites in hexagonal and cubic phases without epitaxial orientation with respect to the Si(111) substrate. Significant oxygen concentration was found in the layer both by RBS and TEM. The electrical measurements have shown laterally homogeneous conductivity in the grown layer. The undoped Mg2Sn layers show increasing resistivity with increasing temperature indicating the scattering process dominates the resistance of the layers, i.e. large concentration of point defects was generated in the layer during the growth process. The Al doped layer shows increase of the resistance at low temperature caused by freeze out of free carriers in the Al doped Mg2Sn layer. The measurements indicate the necessity of protective layer grown over the Mg2Sn layers, and a short time delay between sample preparation and cross sectionalTEM analysis, since the unprotected layer is degraded by the interaction with the ambient.

The Role of MgCl 2 as a Lewis Base in ROMgCl-MgCl 2 Electrolytes for Magnesium-Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, Baofei; Huang, Jinhua; He, Meinan

2016-02-04

A series of strong Lewis acid-free alkoxide/siloxide-based Mg electrolytes were deliberately developed with remarkable oxidative stability up to 3.5 V (vs. Mg/Mg2+). Despite the perception of ROMgCl (R=alkyl, silyl) as a strong base, ROMgCl acts like Lewis acid, whereas the role of MgCl2 in was unambiguously demonstrated as a Lewis base through the identification of the key intermediate using single crystal X-ray crystallography. This Lewis-acid-free strategy should provide a prototype system for further investigation of Mg-ion batteries.

First-principles studies of hydrogen interaction with ultrathin Mg and Mg-based alloy films

NASA Astrophysics Data System (ADS)

Yoon, Mina; Weitering, Hanno H.; Zhang, Zhenyu

2011-01-01

The search for technologically and economically viable storage solutions for hydrogen fuel would benefit greatly from research strategies that involve systematic property tuning of potential storage materials via atomic-level modification. Here, we use first-principles density-functional theory to investigate theoretically the structural and electronic properties of ultrathin Mg films and Mg-based alloy films and their interaction with atomic hydrogen. Additional delocalized charges are distributed over the Mg films upon alloying them with 11.1% of Al or Na atoms. These extra charges contribute to enhance the hydrogen binding strength to the films. We calculated the chemical potential of hydrogen in Mg films for different dopant species and film thickness, and we included the vibrational degrees of freedom. By comparing the chemical potential with that of free hydrogen gas at finite temperature (T) and pressure (P), we construct a hydrogenation phase diagram and identify the conditions for hydrogen absorption or desorption. The formation enthalpies of metal hydrides are greatly increased in thin films, and in stark contrast to its bulk phase, the hydride state can only be stabilized at high P and T (where the chemical potential of free H2 is very high). Metal doping increases the thermodynamic stabilities of the hydride films and thus significantly helps to reduce the required pressure condition for hydrogen absorption from H2 gas. In particular, with Na alloying, hydrogen can be absorbed and/or desorbed at experimentally accessible T and P conditions.

Hysteretic photochromic switching of Eu-Mg defects in GaN links the shallow transient and deep ground states of the Mg acceptor.

PubMed

Singh, A K; O'Donnell, K P; Edwards, P R; Lorenz, K; Kappers, M J; Boćkowski, M

2017-02-03

Although p-type activation of GaN by Mg underpins a mature commercial technology, the nature of the Mg acceptor in GaN is still controversial. Here, we use implanted Eu as a 'spectator ion' to probe the lattice location of Mg in doubly doped GaN(Mg):Eu. Photoluminescence spectroscopy of this material exemplifies hysteretic photochromic switching (HPS) between two configurations, Eu0 and Eu1(Mg), of the same Eu-Mg defect, with a hyperbolic time dependence on 'switchdown' from Eu0 to Eu1(Mg). The sample temperature and the incident light intensity at 355 nm tune the characteristic switching time over several orders of magnitude, from less than a second at 12.5 K, ~100 mW/cm 2 to (an estimated) several hours at 50 K, 1 mW/cm 2 . Linking the distinct Eu-Mg defect configurations with the shallow transient and deep ground states of the Mg acceptor in the Lany-Zunger model, we determine the energy barrier between the states to be 27.7(4) meV, in good agreement with the predictions of theory. The experimental results further suggest that at low temperatures holes in deep ground states are localized on N atoms axially bonded to Mg acceptors.

Determination of the Mg/Mn ratio in foraminiferal coatings: An approach to correct Mg/Ca temperatures for Mn-rich contaminant phases

NASA Astrophysics Data System (ADS)

Hasenfratz, Adam P.; Martínez-García, Alfredo; Jaccard, Samuel L.; Vance, Derek; Wälle, Markus; Greaves, Mervyn; Haug, Gerald H.

2017-01-01

The occurrence of manganese-rich coatings on foraminifera can have a significant effect on their bulk Mg/Ca ratios thereby biasing seawater temperature reconstructions. The removal of this Mn phase requires a reductive cleaning step, but this has been suggested to preferentially dissolve Mg-rich biogenic carbonate, potentially introducing an analytical bias in paleotemperature estimates. In this study, the geochemical composition of foraminifera tests from Mn-rich sediments from the Antarctic Southern Ocean (ODP Site 1094) was investigated using solution-based and laser ablation ICP-MS in order to determine the amount of Mg incorporated into the coatings. The analysis of planktonic and benthic foraminifera revealed a nearly constant Mg/Mn ratio in the Mn coating of ∼0.2 mol/mol. Consequently, the coating Mg/Mn ratio can be used to correct for the Mg incorporated into the Mn phase by using the down core Mn/Ca values of samples that have not been reductively cleaned. The consistency of the coating Mg/Mn ratio obtained in this study, as well as that found in samples from the Panama Basin, suggests that spatial variation of Mg/Mn in foraminiferal Mn overgrowths may be smaller than expected from Mn nodules and Mn-Ca carbonates. However, a site-specific assessment of the Mg/Mn ratio in foraminiferal coatings is recommended to improve the accuracy of the correction.

Comparative study of 250 mg/day terbinafine and 100 mg/day itraconazole for the treatment of cutaneous sporotrichosis.

PubMed

Francesconi, Glaucia; Francesconi do Valle, Antonio Carlos; Passos, Sonia Lambert; de Lima Barros, Mônica Bastos; de Almeida Paes, Rodrigo; Curi, André Luiz Land; Liporage, José; Porto, Cássio Ferreira; Galhardo, Maria Clara Gutierrez

2011-05-01

Itraconazole is currently used for the treatment of cutaneous sporotrichosis. Terbinafine at a daily dose of 250 mg has been successfully applied to the treatment of cutaneous sporotrichosis. To compare the efficacy of 250 mg/day terbinafine and 100 mg/day itraconazole for the treatment of cutaneous sporotrichosis. A bidirectional cohort study was conducted on 55 patients receiving 250 mg/day terbinafine and 249 patients receiving 100 mg/day itraconazole. The latter patients were matched for age and clinical form to the terbinafine group at a ratio of 5:1. Sporothrix schenckii was isolated by culture from all patients (age range: 18-70 years), who were submitted to the standard care protocol consisting of clinical and laboratory evaluation and periodic visits. Cure was observed in 51 (92.7%) patients of the terbinafine group and 229 (92%) of the itraconazole group within a similar mean period of time (11.5 and 11.8 weeks, respectively). An increase in the terbinafine dose to 500 mg was necessary in two patients due to the lack of a response, and one patient presented recurrence. In the itraconazole group, two patients required a dose increase and three presented recurrence. Adverse events were equally frequent among patients receiving terbinafine (n = 4, 7.3%) and itraconazole (n = 19, 7.6%) and were generally mild without the need for drug discontinuation, except for two patients of the itraconazole group. Terbinafine administered at a daily dose of 250 mg is an effective and well-tolerated option for the treatment of cutaneous sporotrichosis.

Use of information and communication technology among dental students and registrars at the faculty of dental sciences, University of Lagos.

PubMed

Butali, A; Adeyemo, W L; Akinshipo, A O; Fashina, A; Savage, K O

2011-01-01

The aim of this study was to investigate the use of information technology amongst dental students, dental nursing students and resident doctors in training at the faculty of dental Surgery University of Lagos. A structured questionnaire was distributed to 58 clinical dental students in 4 th and 5 th years of training in the 2010/2011 academic year, 36 dental nursing students and 63 resident doctors undergoing specialist training. All participants have access to the computers, 2.5% within the University and 31% at home and internet cafes and about 50% have the basic skills required. A significant difference was observed between the resident doctors and clinical dental students (P = 0.003), between resident doctors and dental nursing students (P = 0.0001) when the use of computer for study was compared. Over 95% of participants have access to internet and about 50% of them use the internet for their studies. A significant difference (P = 0.005) was observed between clinical dental students and dental nursing students that use the internet and word processing. The resident doctors used the computers for multimedia and MedLine search tools more than clinical dental students (P = 0.004) and dental nursing students (0.0006). The findings of the study show that dental students and resident doctors in training have the requisite knowledge to operate the computer for use in their study and personal activities.

Close-up view of Grey Glacier from Lago Grey (Grey Lake), taken during NASA's AirSAR 2004 campaign in Chile

NASA Image and Video Library

2004-03-11

Close-up view of Grey Glacier from Lago Grey (Grey Lake), taken during NASA's AirSAR 2004 campaign in Chile. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. Founded in 1959, Torres del Paine National Park encompasses 450,000 acres in the Patagonia region of Chile. This region is being studied by NASA using a DC-8 equipped with an Airborne Synthetic Aperture Radar (AirSAR) developed by scientists from NASA’s Jet Propulsion Laboratory. This is a very sensitive region that is important to scientists because the temperature has been consistently rising causing a subsequent melting of the region’s glaciers. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

Pressure-induced photoluminescence of MgO

NASA Astrophysics Data System (ADS)

Li, Xin; Yuan, Ye; Zhang, Jinbo; Kim, Taehyun; Zhang, Dongzhou; Yang, Ke; Lee, Yongjae; Wang, Lin

2018-05-01

It is reported in this paper that pressure can promote strong photoluminescence (PL) in MgO. The PL measurements of MgO indicate that it has no obvious luminescence at pressures lower than 13 GPa. PL starts to appear upon further compression and reaches a maximum intensity at about 35 GPa. The center of the emission band shows a red shift at lower pressures and turns to a blue shift as pressure exceeds 25 GPa. The PL is preserved upon complete decompression. The defects and micro-strain due to the plastic deformation of MgO are likely responsible for the origin of the luminescence.

Natural abundance (25)Mg solid-state NMR of mg oxyanion systems: a combined experimental and computational study.

PubMed

Cahill, Lindsay S; Hanna, John V; Wong, Alan; Freitas, Jair C C; Yates, Jonathan R; Harris, Robin K; Smith, Mark E

2009-09-28

Solid-state (25)Mg magic angle spinning nuclear magnetic resonance (MAS NMR) data are reported from a range of organic and inorganic magnesium-oxyanion compounds at natural abundance. To constrain the determination of the NMR interaction parameters (delta(iso), chi(Q), eta(Q)) data have been collected at three external magnetic fields (11.7, 14.1 and 18.8 T). Corresponding NMR parameters have also been calculated by using density functional theory (DFT) methods using the GIPAW approach, with good correlations being established between experimental and calculated values of both chi(Q) and delta(iso). These correlations demonstrate that the (25)Mg NMR parameters are very sensitive to the structure, with small changes in the local Mg(2+) environment and the overall hydration state profoundly affecting the observed spectra. The observations suggest that (25)Mg NMR spectroscopy is a potentially potent probe for addressing some key problems in inorganic materials and of metal centres in biologically relevant molecules.

Responder analysis of a randomized comparison of the 13.3 mg/24 h and 9.5 mg/24 h rivastigmine patch.

PubMed

Molinuevo, José L; Frölich, Lutz; Grossberg, George T; Galvin, James E; Cummings, Jeffrey L; Krahnke, Tillmann; Strohmaier, Christine

2015-01-01

OPtimizing Transdermal Exelon In Mild-to-moderate Alzheimer's disease (OPTIMA) was a randomized, double-blind comparison of 13.3 mg/24 h versus 9.5 mg/24 h rivastigmine patch in patients with mild-to-moderate Alzheimer's disease who declined despite open-label treatment with 9.5 mg/24 h patch. Over 48 weeks of double-blind treatment, high-dose patch produced greater functional and cognitive benefits compared with 9.5 mg/24 h patch. Using OPTIMA data, a post-hoc responder analysis was performed to firstly, compare the proportion of patients demonstrating improvement or absence of decline with 13.3 mg/24 h versus 9.5 mg/24 h patch; and secondly, identify predictors of improvement or absence of decline. 'Improvers' were patients who improved on the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) by ≥4 points from baseline, and did not decline on the instrumental domain of the Alzheimer's Disease Cooperative Study-Activities of Daily Living scale (ADCS-IADL). 'Non-decliners' were patients who did not decline on either scale. Overall, 265 patients randomized to 13.3 mg/24 h and 271 to 9.5 mg/24 h patch met the criteria for inclusion in the intention-to-treat population and were included in the analyses. Significantly more patients were 'improvers' with 13.3 mg/24 h compared with 9.5 mg/24 h patch at Weeks 24 (44 (16.6%) versus 19 (7.0%); P < 0.001) and 48 (21 (7.9%) versus 10 (3.7%); P = 0.023). A significantly greater proportion of patients were 'non-decliners' with 13.3 mg/24 h compared with 9.5 mg/24 h patch at Week 24 (71 (26.8%) versus 44 (16.2%); P = 0.002). At Week 48, there was a trend in favor of 13.3 mg/24 h patch. Functional and cognitive assessment scores at double-blind baseline did not consistently predict effects at Weeks 24 or 48. More patients with mild-to-moderate Alzheimer's disease who are titrated to 13.3 mg/24 h rivastigmine patch at time of decline are 'improvers' or 'non-decliners' i

Mg/Ti multilayers: Structural and hydrogen absorption properties

NASA Astrophysics Data System (ADS)

Baldi, A.; Pálsson, G. K.; Gonzalez-Silveira, M.; Schreuders, H.; Slaman, M.; Rector, J. H.; Krishnan, G.; Kooi, B. J.; Walker, G. S.; Fay, M. W.; Hjörvarsson, B.; Wijngaarden, R. J.; Dam, B.; Griessen, R.

2010-06-01

Mg-Ti alloys have uncommon optical and hydrogen absorbing properties, originating from a “spinodal-like” microstructure with a small degree of chemical short-range order in the atomic distribution. In the present study we artificially engineer short-range order by depositing Pd-capped Mg/Ti multilayers with different periodicities. Notwithstanding the large lattice mismatch between Mg and Ti, the as-deposited metallic multilayers show good structural coherence. On exposure to H2 gas a two-step hydrogenation process occurs with the Ti layers forming the hydride before Mg. From in situ measurements of the bilayer thickness Λ at different hydrogen pressures, we observe large out-of-plane expansions of Mg and Ti layers on hydrogenation, indicating strong plastic deformations in the films and a consequent shortening of the coherence length. On unloading at room temperature in air, hydrogen atoms remain trapped in the Ti layers due to kinetic constraints. Such loading/unloading sequence can be explained in terms of the different thermodynamic properties of hydrogen in Mg and Ti, as shown by diffusion calculations on a model multilayered systems. Absorption isotherms measured by hydrogenography can be interpreted as a result of the elastic clamping arising from strongly bonded Mg/Pd and broken Mg/Ti interfaces.

Ground-state properties of neutron-rich Mg isotopes

NASA Astrophysics Data System (ADS)

Watanabe, S.; Minomo, K.; Shimada, M.; Tagami, S.; Kimura, M.; Takechi, M.; Fukuda, M.; Nishimura, D.; Suzuki, T.; Matsumoto, T.; Shimizu, Y. R.; Yahiro, M.

2014-04-01

We analyze recently measured total reaction cross sections for 24-38Mg isotopes incident on 12C targets at 240 MeV/nucleon by using the folding model and antisymmetrized molecular dynamics (AMD). The folding model well reproduces the measured reaction cross sections, when the projectile densities are evaluated by the deformed Woods-Saxon (def-WS) model with AMD deformation. Matter radii of 24-38Mg are then deduced from the measured reaction cross sections by fine tuning the parameters of the def-WS model. The deduced matter radii are largely enhanced by nuclear deformation. Fully microscopic AMD calculations with no free parameter well reproduce the deduced matter radii for 24-36Mg, but still considerably underestimate them for 37,38Mg. The large matter radii suggest that 37,38Mg are candidates for deformed halo nucleus. AMD also reproduces other existing measured ground-state properties (spin parity, total binding energy, and one-neutron separation energy) of Mg isotopes. Neutron-number (N) dependence of deformation parameter is predicted by AMD. Large deformation is seen from 31Mg with N =19 to a drip-line nucleus 40Mg with N =28, indicating that both the N =20 and 28 magicities disappear. N dependence of neutron skin thickness is also predicted by AMD.

A High Pressure Post-Perovskite Phase Transition in NaMgF3--a MgSiO3 Analog Material

NASA Astrophysics Data System (ADS)

Martin, C.; Liu, H.; Crichton, W.; Parise, J. B.

2005-12-01

Since Murakami et al. (2004) identified a perovskite (pv, Pbnm) to post-perovskite (ppv, Cmcm) structural phase transition in MgSiO3, the transition has been reported to occur in many oxides at ultra-high pressures (>60 GPa). The layered ppv structure is rapidly shaping a better understanding of seismic anisotropy in the controversial D" region of the lower mantle. While the ppv unit cell may be derived from indexing of the powder pattern, the structure adopted at high pressure is experimentally ill-constrained due to compromised powder diffraction statistics typically obtained from small sample volumes at extreme conditions in the diamond anvil cell. NaMgF3, a structural analog material to MgSiO3 pv, exhibits a large compressibility and presents the possibility of reducing the pv-ppv transition pressure, allowing for improved powder statistics from a larger sample volume. In accordance with our previous theoretical and experimental evidence (Liu et al., 2005; Parise et al., 2004), we have observed a phase transition in NaMgF3 during two recent independent high pressure trials utilizing monochromatic x-ray diffraction and in-situ laser heating in the diamond anvil cell at pressures as low as 30 GPa. From our analysis thus far, we have found the unit cell of the high pressure phase cannot be indexed according to pv (Pbnm) or close permutations of ppv (Cmcm) unit cells predicted for NaMgF3 or unit cells observed for ppv MgSiO3 and MgGeO3. In addition, we have precluded a breakdown to high pressure phases of NaF and MgF3 as an explanation for the observed data. Upon pressure release, we observe diffraction peaks from the high pressure phase in the absence of pv NaMgF3, suggesting the high pressure structure is quenchable to ambient conditions. The results of the work in progress will be presented at the meeting.

Microwave surface resistance of MgB2

NASA Astrophysics Data System (ADS)

Zhukov, A. A.; Purnell, A.; Miyoshi, Y.; Bugoslavsky, Y.; Lockman, Z.; Berenov, A.; Zhai, H. Y.; Christen, H. M.; Paranthaman, M. P.; Lowndes, D. H.; Jo, M. H.; Blamire, M. G.; Hao, Ling; Gallop, J.; MacManus-Driscoll, J. L.; Cohen, L. F.

2002-04-01

The microwave power and frequency dependence of the surface resistance of MgB2 films and powder samples were studied. Sample quality is relatively easy to identify by the breakdown in the ω2 law for poor-quality samples at all temperatures. The performance of MgB2 at 10 GHz and 21 K was compared directly with that of high-quality YBCO films. The surface resistance of MgB2 was found to be approximately three times higher at low microwave power and showed an onset of nonlinearity at microwave surface fields ten times lower than the YBCO film. It is clear that MgB2 films are not yet optimized for microwave applications.

Pharmacodynamic target attainment analysis against Streptococcus pneumoniae using levofloxacin 500 mg, 750 mg and 1000 mg once daily in plasma (P) and epithelial lining fluid (ELF) of hospitalized patients with community acquired pneumonia (CAP).

PubMed

Noreddin, Ayman M; Marras, Theodore K; Sanders, Kevin; Chan, Charles K N; Hoban, Daryl J; Zhanel, George G

2004-11-01

The pharmacokinetics and pharmacodynamics of levofloxacin in patients with respiratory infections such as community-acquired pneumonia (CAP) are poorly documented. This work aimed at assessing the pharmacodynamic target attainment against Streptococcus pneumoniae using levofloxacin 500 mg, 750 mg and 1000 mg administered once daily in plasma (P) and epithelial lining fluid (ELF) of hospitalized patients with community acquired pneumonia. The pharmacokinetics of levofloxacin in elderly (>/=65 years) compared with younger patients (<65 years) hospitalized with CAP were simulated. Susceptibility data with S. pneumoniae from our ongoing national surveillance study (Canadian Respiratory Organism Susceptibility Study-CROSS) were then used to produce pharmacodynamic indices of AUC(0-24)/MIC(all.) Monte Carlo simulations were then used to analyse target attainment of levofloxacin using doses of 500 mg, 750 mg and 1000 mg once daily to achieve free drug AUC(0-24)/MIC(all) >/= 30-100 versus S. pneumoniae in patients with CAP. Pharmacokinetics of levofloxacin simulated after 500 mg, 750 mg and 1000 mg once daily dosing resulted in levofloxacin volume of distribution: elderly patients = younger patients, while levofloxacin clearance was: elderly patients < younger patients. Levofloxacin t(1/2) values were longer in elderly patients (9.8 +/- 2.5h) than younger patients with CAP (7.4 +/- 2.5h). Free levofloxacin AUC(0-24) as well as AUC(0-24)/MIC(all) for S. pneumoniae were higher in elderly patients than younger patients. Monte Carlo simulation using levofloxacin 500 mg yielded probabilities of achieving free-drug AUC(0-24)/MIC(all) of 30 in P and ELF (95.7% and 98.1%) in elderly and younger patients (72.7% and 80.6%) respectively. Levofloxacin 750 mg and 1000 mg once daily had probability of achieving free-drug AUC(0-24)/MIC(all) of 30 in P/ELF of 98.1%/98.6% and 99.2%/99.0%, respectively, in elderly patients compared with 89.9%/94.1% and 95.2%/96.5%, respectively, for younger

Effect of Si, Mg, and Mg Zn doping on structural properties of a GaN layer grown by metalorganic chemical vapor deposition

NASA Astrophysics Data System (ADS)

Cho, H. K.; Lee, J. Y.; Kim, K. S.; Yang, G. M.

2001-12-01

We have studied the structural properties of undoped, Si-doped, Mg-doped, and Mg-Zn codoped GaN using high-resolution X-ray diffraction (HRXRD) and transmission electron microscopy. When compared with undoped GaN, the dislocation density at the surface of the GaN layer decreases with Si doping and increases with Mg doping. In addition, we observed a reduction of dislocation density by codoping with Zn atoms in the Mg-doped GaN layer. The full width at half maximum of HRXRD shows that Si doping and Mg-Zn codoping improve the structural quality of the GaN layer as compared with undoped and Mg-doped GaN, respectively.

Global Mapping of Mg-Number Derived from Clementine Data.

NASA Astrophysics Data System (ADS)

Cahill, J. T.; Lucey, P. G.; Gillis, J. J.; Steutel, D.

2004-12-01

The global mapping of the lunar surface using the petrological parameter Mg-number (Mg*) was undertaken because Mg*, or the ratio of Mg to the sum of Mg and Fe on an atomic basis, is an important disciminator in defining and understanding lunar rocks. The dominant lunar rock types, ferroan anorthosites (FAN), high-magnisium suite (HMS), and high-alkali suite (HAS) rocks all vary in Mg* depending upon the petrologic scenario that formed them. Of particular interest are FAN mineralogy and chemistry, which varies from high-Mg# (~70) troctolites to low-Mg# norites (~50) and for some time has been considered to represent a single magma frac-tionation trend. However, recent studies have also shown that the crystallization of FAN rocks may have been more complicated than originally thought. James et al. [1] found that instead of one simple fractionation trend for ferroan anorthosites, there may have been four. Studies by [2], [3], and [4] using Apollo and lunar meteorites for analysis have also eluded to the possibility that FAN rocks may have evolved from a more complex source or process. Therefore a global assessment of lithologies and corresponding Mg* is of great value for lunar petrology. In a remote sensing context, Mg* is the most important control on the spectral properties of lunar mafic silicates. For stoichiometric orthopyroxene and olivine, Mg* is mathematically linked to the Fe content that controls the overall reflectance and intensity of absorption. The changes in band centers and shape that accompany the structural changes as Fe substitutes for Mg along the solid solution series have long been recognized; these changes are highly correlated with Mg*. In clinopyroxene, the strong effect of Ca on structure makes this element important, but Mg* has the dominant effect on reflectance and a comparable effect on spectral shape. In this study, the lunar surface is quantitatively mapped using a theoretical treatment of mineralogic spectra and the effect of

Interstitial Fe in MgO

NASA Astrophysics Data System (ADS)

Mølholt, T. E.; Mantovan, R.; Gunnlaugsson, H. P.; Svane, A.; Masenda, H.; Naidoo, D.; Bharuth-Ram, K.; Fanciulli, M.; Gislason, H. P.; Johnston, K.; Langouche, G.; Ólafsson, S.; Sielemann, R.; Weyer, G.

2014-01-01

Isolated 57Fe atoms were studied in MgO single-crystals by emission Mössbauer spectroscopy following implantation of 57Mn decaying to 57Fe. Four Mössbauer spectral components were found corresponding to different Fe lattice positions and/or charge states. Two components represent Fe atoms substituting Mg as Fe2+ and Fe3+, respectively; a third component is due to Fe in a strongly implantation-induced disturbed region. The fourth component, which is the focus of this paper, can be assigned to Fe at an interstitial site. Comparison of its measured isomer shift with ab initio calculations suggests that the interstitial Fe is located on, or close to, the face of the rock-salt MgO structure. To harmonize such an assignment with the measured near-zero quadrupole interaction a local motion process (cage motion) of the Fe has to be stipulated. The relation of such a local motion as a starting point for long range diffusion is discussed.

Natural ageing responses of duplex structured Mg-Li based alloys

PubMed Central

Li, C. Q.; Xu, D. K.; Wang, B. J.; Sheng, L. Y.; Qiao, Y. X.; Han, E. H.

2017-01-01

Natural ageing responses of duplex structured Mg-6%Li and Mg-6%Li-6%Zn-1.2%Y alloys have been investigated. Microstructural analyses revealed that the precipitation and coarsening process of α-Mg particles could occur in β-Li phases of both two alloys during ageing process. Since a certain amount of Mg atoms in β-Li phases were consumed for the precipitation of abundant tiny MgLiZn particles, the size of α-Mg precipitates in Mg-6%Li-6%Zn-1.2%Y alloy was relatively smaller than that in Mg-6%Li alloy. Micro hardness measurements demonstrated that with the ageing time increasing, the α-Mg phases in Mg-6%Li alloy could have a constant hardness value of 41 HV, but the contained β-Li phases exhibited a slight age-softening response. Compared with the Mg-6%Li alloy, the age-softening response of β-Li phases in Mg-6%Li-6%Zn-1.2%Y alloy was much more profound. Meanwhile, a normal age-hardening response of α-Mg phases was maintained. Tensile results indicated that obvious ageing-softening phenomenon in terms of macro tensile strength occurred in both two alloys. Failure analysis demonstrated that for the Mg-6%Li alloy, cracks were preferentially initiated at α-Mg/β-Li interfaces. For the Mg-6%Li-6%Zn-1.2%Y alloy, cracks occurred at both α-Mg/β-Li interfaces and slip bands in α-Mg and β-Li phases. PMID:28053318

National health insurance scheme: How receptive are the private healthcare practitioners in a local government area of Lagos state.

PubMed

Christina, Campbell Princess; Latifat, Taiwo Toyin; Collins, Nnaji Feziechukwu; Olatunbosun, Abolarin Thaddeus

2014-11-01

National Health Insurance Scheme (NHIS) is one of the health financing options adopted by Nigeria for improved healthcare access especially to the low income earners. One of the key operators of the scheme is the health care providers, thus their uptake of the scheme is fundamental to the survival of the scheme. The study reviewed the uptake of the NHIS by private health care providers in a Local Government Area in Lagos State. To assess the uptake of the NHIS by private healthcare practitioners. This descriptive cross-sectional study recruited 180 private healthcare providers selected by multistage sampling technique with a response rate of 88.9%. Awareness, knowledge and uptake of NHIS were 156 (97.5%), 110 (66.8%) and 97 (60.6%), respectively. Half of the respondents 82 (51.3%) were dissatisfied with the operations of the scheme. Major reasons were failure of entitlement payment by Health Maintenance Organisations 13 (81.3%) and their incurring losses in participating in the scheme 8(50%). There was a significant association between awareness, level of education, knowledge of NHIS and registration into scheme by the respondents P-value < 0.05. Awareness and knowledge of NHIS were commendable among the private health care providers. Six out of 10 had registered with the NHIS but half of the respondents 82 (51.3%) were dissatisfied with the scheme and 83 (57.2%) regretted participating in the scheme. There is need to improve payment modalities and ensure strict adherence to laid down policies.

Mechanical properties and corrosion behavior of Mg-HAP composites.

PubMed

Campo, R Del; Savoini, B; Muñoz, A; Monge, M A; Garcés, G

2014-11-01

Mg and Mg-HAP composites containing 5, 10 and 15 wt% of hydroxyapatite have been produced following a powder metallurgy route that consists of mixing raw powders and consolidation by extrusion. The microstructure, texture, mechanical behavior and resistance to corrosion under a PBS solution have been studied. Addition of HAP increases the microhardness of the composites, however the yield strength under compression slightly decreases. Texture analyses reveal a fiber texture for pure Mg that is weakened increasing the HAP fraction. This texture promotes twinning and softening of Mg and Mg-5HAP during the initial deformation stages. Mg-10HAP and Mg-15HAP present a strain-hardening dependence showing no softening. The volume fraction of HAP particles weakens the texture and favors the activation of secondary slip systems. Corrosion experiments in PBS solution have shown that Mg-5HAP exhibits the best resistance to corrosion. Texture and porosity appear to be the main material features controlling the corrosion rates of Mg-HAP composites under the present conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dopant radial inhomogeneity in Mg-doped GaN nanowires.

PubMed

Siladie, Alexandra-Madalina; Amichi, Lynda; Mollard, Nicolas; Mouton, Isabelle; Bonef, Bastien; Bougerol, Catherine; Grenier, Adeline; Robin, Eric; Jouneau, Pierre-Henri; Garro, Nuria; Cros, Ana; Daudin, Bruno

2018-06-22

Using atom probe tomography, it is demonstrated that Mg doping of GaN nanowires grown by Molecular Beam Epitaxy results in a marked radial inhomogeneity, namely a higher Mg content in the periphery of the nanowires. This spatial inhomogeneity is attributed to a preferential incorporation of Mg through the m-plane sidewalls of nanowires and is related to the formation of a Mg-rich surface which is stabilized by hydrogen. This is further supported by Raman spectroscopy experiments which give evidence of Mg-H complexes in the doped nanowires. A Mg doping mechanism such as this, specific to nanowires, may lead to higher levels of Mg doping than in layers, boosting the potential interest of nanowires for light emitting diode applications.

Dopant radial inhomogeneity in Mg-doped GaN nanowires

NASA Astrophysics Data System (ADS)

Siladie, Alexandra-Madalina; Amichi, Lynda; Mollard, Nicolas; Mouton, Isabelle; Bonef, Bastien; Bougerol, Catherine; Grenier, Adeline; Robin, Eric; Jouneau, Pierre-Henri; Garro, Nuria; Cros, Ana; Daudin, Bruno

2018-06-01

Using atom probe tomography, it is demonstrated that Mg doping of GaN nanowires grown by Molecular Beam Epitaxy results in a marked radial inhomogeneity, namely a higher Mg content in the periphery of the nanowires. This spatial inhomogeneity is attributed to a preferential incorporation of Mg through the m-plane sidewalls of nanowires and is related to the formation of a Mg-rich surface which is stabilized by hydrogen. This is further supported by Raman spectroscopy experiments which give evidence of Mg-H complexes in the doped nanowires. A Mg doping mechanism such as this, specific to nanowires, may lead to higher levels of Mg doping than in layers, boosting the potential interest of nanowires for light emitting diode applications.

Rational use of medicines: assessing progress using primary health centres in Shomolu local government area of Lagos, Nigeria.

PubMed

Oyeyemi, A S; Ogunleye, O A

2013-01-01

Medicines (drugs) are a critical component in the prevention and treatment of diseases. Their rational use is important to maximize their benefits and prevent undesirable effects. This study was conducted to assess progress with rational use of medicines at primary care level using recommended indicators. The cross-sectional descriptive study was conducted in four primary health centres in Somolu Local Government Area (LGA) of Lagos State, Nigeria. It employed retrospective and prospective data collection methods. From the four centres, prescription notes of 600 clinical encounters spanning one year were analyzed for prescribing indicators and a checklist was administered for facility indicators. For the 600 clinical encounters studied, 2802 drugs were prescribed. The mean number of drugs per encounter was 4.7 ± 2.1; 75.6% of drugs were prescribed by generic name; prescriptions containing at least an antibiotic averaged 48.5%, while those with at least an injection prescribed were 21%. Of all the drugs prescribed, 83.2% were from the National Essential Drugs List (NEDL). On the average, 86.5% of key essential drugs were available in the health centres but none of the centres had a copy of the NEDL or drug formulary. There were wide variations in some of the indicators across the four facilities. The study showed progress in some indicators when compared with previous studies but gaps still exist. We recommend training on rational use of medicines for health workers in the facilities and distribution of copies of NEDL to all the facilities.

Matter radii of {sup 32-35}Mg

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kanungo, R.; Perro, C.; Prochazka, A.

The interaction cross sections of {sup 32-35}Mg at 900A MeV have been measured using the fragment separator at GSI. The deviation from the r{sub 0}A{sup 1/3} trend is slightly larger for {sup 35}Mg, signaling the possible formation of a longer tail in the neutron distribution for {sup 35}Mg. The radii extracted from a Glauber model analysis with Fermi densities are consistent with models predicting the development of neutron skins.

Microstructural Aspects of Localized Corrosion Behavior of Mg Alloys

NASA Astrophysics Data System (ADS)

Chu, Peng-Wei

Combining high specific strength and unique electrochemical properties, magnesium (Mg) alloys are promising lightweight materials for various applications from automotive, consumer electronics, biomedical body implant, to battery electrodes. Engineering solutions such as coatings have enabled the use of Mg alloys, despite their intrinsic low corrosion resistance. Consequently, the fundamental mechanisms responsible for the unique localized corrosion behavior of bare Mg alloys, the associated abnormal hydrogen evolution response, and the relationships between corrosion behavior and alloy microstructure are still unsolved. This thesis aims to uncover the specificities of Mg corrosion and the roles of alloy chemistry and microstructure. To this end, multiscale site-specific microstructure characterization techniques, including in situ optical microscopy, scanning electron microscopy with focused ion beam milling, and transmission electron microscopy, combined with electrochemical analysis and hydrogen evolution rate monitoring, were performed on pure Mg and selected Mg alloys under free corrosion and anodic polarization, revealing key new information on the propagation mode of localized corrosion and the role of alloy microstructures, thereby confirming or disproving the validity of previously proposed corrosion models. Uniform surface corrosion film on Mg alloys immersed in NaCl solution consisted a bi-layered structure, with a porous Mg(OH)2 outer layer on top of a MgO inner layer. Presence of fine scale precipitates in Mg alloys interacted with the corrosion reaction front, reducing the corrosion rate and surface corrosion film thickness. Protruding hemispherical dome-like corrosion products, accompanied by growing hydrogen bubbles, formed on top of the impurity particles in Mg alloys by deposition of Mg(OH)2 via a microgalvanic effect. Localized corrosion on Mg alloys under both free immersion and anodic polarization was found to be governed by a common mechanism

Laser-induced chemiluminescence of NaMg

NASA Astrophysics Data System (ADS)

Benard, D. J.; Michels, H. H.

1982-03-01

An unstructured continuum emission around 670 nm was observed when Mg was added to an optically pumped heat pipe containing Na and K vapor, in good agreement with ab initio calculations of the NaMg potential energy curves. The corresponding excitation spectrum showed that the incident radiation was observed by NaK molecules (X → C transitions).

A randomized, double-blind, placebo-controlled study of acetaminophen 1000 mg versus acetaminophen 650 mg for the treatment of postsurgical dental pain.

PubMed

Qi, Daniel S; May, Lisa G; Zimmerman, Brenda; Peng, Penny; Atillasoy, Evren; Brown, Jean D; Cooper, Stephen A

2012-12-01

Although acetaminophen is one of the oldest and most widely used of all analgesic drugs, the incremental benefit of the 1000-mg dose compared with the 650-mg dose has been questioned. The aim of this study was to assess the relative efficacy of acetaminophen 1000 mg versus acetaminophen 650 mg over a 6-hour period in patients experiencing at least moderate postsurgical dental pain. This single-center, randomized, double-blind, placebo-controlled, single-dose study enrolled patients aged 16 to 50 years who experienced at least moderate pain after surgical removal of impacted third molars. Each patient received either acetaminophen 1000 mg (n = 239), acetaminophen 650 mg (n = 241), or placebo (n = 60) when they had at least moderate pain and a score ≥50 on the 100-mm Visual Analog Scale (VAS) postsurgically. Pain intensity and pain relief were measured over 6 hours (VAS 0-100 mm). All 540 patients (52% female; age range, 16-30 years; 95% white) were included in the efficacy analysis. For the primary efficacy endpoint (weighted sum of the pain intensity difference from baseline [PID] and pain relief [PAR] scores over 6 hours [SPRID6]), acetaminophen 1000 mg demonstrated a 24% improvement compared with acetaminophen 650 mg (529.4 vs 427.3; P = 0.001). In addition, acetaminophen 650 mg was significantly superior compared with placebo (P < 0.001). The weighted sum of PID over 6 hours (SPID6), the weighted total pain relief over 6 hours (TOTPAR6), and the percentage of patients with >50% of the maximum possible TOTPAR6 score were significantly greater for patients treated with acetaminophen 1000 mg compared with those receiving acetaminophen 650 mg (P ≤ 0.006) or placebo (P < 0.001) and for patients treated with acetaminophen 650 mg compared with placebo (P < 0.001). Time to rescue, rescue rates through 4 and 6 hours, and patient global assessment demonstrated similar findings. Patients treated with acetaminophen 1000 mg or 650 mg had a significantly different

Clinical trial: the treatment of gastro-oesophageal reflux disease in primary care--prospective randomized comparison of rabeprazole 20 mg with esomeprazole 20 and 40 mg.

PubMed

Eggleston, A; Katelaris, P H; Nandurkar, S; Thorpe, P; Holtmann, G

2009-05-01

A trial of empirical PPI therapy is usual practice for most patients with symptoms of gastro-oesophageal reflux disease (GERD) in primary care. To determine if the 4-week efficacy of rabeprazole 20 mg for resolving heartburn and regurgitation symptoms is non-inferior to esomeprazole 40 mg or 20 mg. In all, 1392 patients were randomized to rabeprazole 20 mg, esomeprazole 20 mg or 40 mg once daily. Patients, doctors and assessors were blinded. Symptom resolution data were collected on days 0-7 and day-28 using the Patient Assessment of Upper Gastrointestinal Disorders Symptom Severity Index with a shortened version used on days 8-27. Rabeprazole 20 mg was non-inferior to esomeprazole 40 mg for complete resolution of regurgitation and satisfactory resolution of heartburn and regurgitation. For complete heartburn resolution, the efficacy of rabeprazole 20 mg and esomeprazole 40 mg was statistically indistinguishable, although the non-inferiority test was inconclusive. Rabeprazole 20 mg was non-inferior to esomeprazole 20 mg for all outcomes. In uninvestigated GERD patients, rabeprazole 20 mg was non-inferior to esomeprazole 40 mg for complete and satisfactory relief of regurgitation and satisfactory relief of heartburn, and not different for complete resolution of heartburn.

Low-power, high-uniform, and forming-free resistive memory based on Mg-deficient amorphous MgO film with rough surface

NASA Astrophysics Data System (ADS)

Guo, Jiajun; Ren, Shuxia; Wu, Liqian; Kang, Xin; Chen, Wei; Zhao, Xu

2018-03-01

Saving energy and reducing operation parameter fluctuations remain crucial for enabling resistive random access memory (RRAM) to emerge as a universal memory. In this work, we report a resistive memory device based on an amorphous MgO (a-MgO) film that not only exhibits ultralow programming voltage (just 0.22 V) and low power consumption (less than 176.7 μW) but also shows excellent operative uniformity (the coefficient of variation is only 1.7% and 2.2% for SET and RESET voltage, respectively). Moreover, it also shows a forming-free characteristic. Further analysis indicates that these distinctive properties can be attributed to the unstable local structures and the rough surface of the Mg-deficient a-MgO film. These findings show the potential of using a-MgO in high-performance nonvolatile memory applications.

Surface exciton emission of MgO crystals

NASA Astrophysics Data System (ADS)

Kuang, Wen-Jian; Li, Qing; Chen, Yu-Xiang; Hu, Kai; Wang, Ning-Hui; Xing, Fang-Li; Yan, Qun; Sun, Shuai-Shuai; Huang, Yan; Tao, Ye; Tolner, Harm

2013-09-01

MgO crystals have been exposed to vacuum ultraviolet (VUV) radiation from a synchrotron, with energies up to 9 eV, and the emitted light, at wavelengths above 200 nm, was observed. It is concluded that bulk excitons, play an important role in the diffusion of energy inside MgO crystals, resulting in 5.85 eV (212 nm) emission from the MgO terraces of large (0.2-2 µm) MgO : F crystals. In the case of aliovalent impurity doping, then the bulk exciton energy is also transferred to the Vk centres and 5.3 eV (235 nm) light is emitted. Both fluorine and silicon doping appear to promote UV surface emission, acting similarly to an ns2 ion inside MgO, while strong scandium doping is killing the surface emission completely. The 212 nm surface UV emission and the 235 nm bulk UV emission can be excited only at the bandgap edge. Broadband visible light, centred around 400 nm, is also emitted. Contrary to the UV emission, this is not generated when excited at the bandgap edge; instead, we find that it is only excited at sub-bandgap energies, with a maximum at the 5C surface excitation energy of 5.71 eV (217 nm) for the MgO terraces.

Knowledge and Acceptability of Human Papillomavirus Vaccination among Women Attending the Gynaecological Outpatient Clinics of a University Teaching Hospital in Lagos, Nigeria.

PubMed

Okunade, Kehinde S; Sunmonu, Oyebola; Osanyin, Gbemisola E; Oluwole, Ayodeji A

2017-01-01

This study was aimed at determining the knowledge and acceptability of HPV vaccine among women attending the gynaecology clinics of the Lagos University Teaching Hospital (LUTH). This was a descriptive cross-sectional study involving 148 consecutively selected women attending the gynaecology clinic of LUTH. Relevant information was obtained from these women using an interviewer-administered questionnaire. The data was analysed and then presented by simple descriptive statistics using tables and charts. Chi-square statistics were used to test the association between the sociodemographical variables and acceptance of HPV vaccination. All significance values were reported at P < 0.05. The mean age of the respondents was 35.7 ± 9.7 years. The study showed that 36.5% of the respondents had heard about HPV infection while only 18.9% had knowledge about the existence of HPV vaccines. Overall, 81.8% of the respondents accepted that the vaccines could be administered to their teenage girls with the level of education of the mothers being the major determinant of their acceptability ( P = 0.013). Awareness of HPV infections and existence of HPV vaccines is low. However, the acceptance of HPV vaccines is generally high. Efforts should be made to increase the awareness about cervical cancer, its aetiologies, and prevention via HPV vaccination.

Paleoenvironmental dynamics in South Amazonia, Brazil, during the last 35,000 years inferred from pollen and geochemical records of Lago do Saci

NASA Astrophysics Data System (ADS)

Fontes, D.; Cordeiro, R. C.; Martins, G. S.; Behling, H.; Turcq, B.; Sifeddine, A.; Seoane, J. C. S.; Moreira, L. S.; Rodrigues, R. A.

2017-10-01

Paleoenvironmental changes for the last 35,000 years were reconstructed from palynological, sedimentological and organic geochemical evidence from a well-dated sediment core from Lago do Saci (South Amazonia). Dry climatic conditions occurred between 35,000 and 18,200 cal yr BP as recorded by high frequencies of open savanna taxa and low lake level indicated by Sagittaria and low Total Organic Carbon content. Cold temperatures are indicated by the presence of Podocarpus and Ilex. A sedimentation hiatus observed between 18,200 and 9200 cal yr BP was likely related to dry conditions. The beginning of the Holocene was marked by rainforest expansion and an increase in carbon content that represented high lake levels and warmer and wetter climate conditions. Between 7500 and 5000 cal yr BP, the expansion of open savanna, seasonal forest elements and abundant black carbon suggests a dry phase. After 5000 cal yr BP, rainforest expansion and higher lake levels indicate a return to wetter conditions. A reduction of flooding taxa (Celtis and Mauritia) between 1800 and 1300 cal yr BP, high lake level conditions and maintenance of a forest physiognomy, suggests a decrease of regional precipitation and subsequent reduction of the flooded areas in a still humid climate regime.

Catalytically Enhanced Hydrogen Sorption in Mg-MgH2 by Coupling Vanadium-Based Catalyst and Carbon Nanotubes

PubMed Central

Kadri, Atikah; Jia, Yi; Chen, Zhigang; Yao, Xiangdong

2015-01-01

Mg (MgH2)-based composites, using carbon nanotubes (CNTs) and pre-synthesized vanadium-based complex (VCat) as the catalysts, were prepared by high-energy ball milling technique. The synergistic effect of coupling CNTs and VCat in MgH2 was observed for an ultra-fast absorption rate of 6.50 wt. % of hydrogen per minute and 6.50 wt. % of hydrogen release in 10 min at 200 °C and 300 °C, respectively. The temperature programmed desorption (TPD) results reveal that coupling VCat and CNTs reduces both peak and onset temperatures by more than 60 °C and 114 °C, respectively. In addition, the presence of both VCat and CNTs reduces the enthalpy and entropy of desorption of about 7 kJ/mol H2 and 11 J/mol H2·K, respectively, as compared to those of the commercial MgH2, which ascribe to the decrease of desorption temperature. From the study of the effect of CNTs milling time, it is shown that partially destroyed CNTs (shorter milling time) are better to enhance the hydrogen sorption performance.

Decay of 34Mg

NASA Astrophysics Data System (ADS)

Chaney, Donlad; Benjamin Luna Collaboration

2017-09-01

One of concepts of modern physics that is not understood is the strong nuclear force. One manifestation of this is our lack of understanding of so-called `islands of inversion', which are groups of nuclides which have deformed ground states. It is known that 34Mg is included in this island, and that its decay (34Al) has a mixed ground state configuration. By studying their decays we hoped to discover definitive information about the branching ratios and the half lives of 34Mg and 34Al. In order to accomplish these goals, we studied the gamma radiation from the decays of 34Mg and 34Al. A Magnesium beam was implanted into a strip of mylar tape and transported to the center of an array of scintillators and germanium detectors, which has allowed us to determine the half-lives for the decays, and the branching ratios for the beta decay. My work on this project began with writing scripts to draw histograms with the data, and using those histograms to gather information that would allow me to gate our data on any number of variables and pieces of information. By cutting out bad portions of our data collection runs and gating on the coincidence of beta decays and other gamma rays, I was able to cut out a significant amount background radiation from our data.

Acid-inhibitory effects of vonoprazan 20 mg compared with esomeprazole 20 mg or rabeprazole 10 mg in healthy adult male subjects--a randomised open-label cross-over study.

PubMed

Sakurai, Y; Mori, Y; Okamoto, H; Nishimura, A; Komura, E; Araki, T; Shiramoto, M

2015-09-01

Proton pump inhibitors (PPIs) are widely used for the treatment of acid-related diseases. Vonoprazan is a member of a new class of acid suppressants; potassium-competitive acid blockers. Vonoprazan may thus be an alternative to PPIs. To evaluate efficacy, rapidity and duration of acid-inhibitory effects of vonoprazan vs. two control PPIs, esomeprazole and rabeprazole, in 20 healthy Japanese adult male volunteers with CYP2C19 extensive metaboliser genotype. In this randomised, open-label, two-period cross-over study, vonoprazan 20 mg and esomeprazole 20 mg (Study V vs. E) or rabeprazole 10 mg (Study V vs. R) were orally administered daily for 7 days. Primary pharmacodynamic endpoint was gastric pH over 24 h measured as percentage of time pH ≥3, ≥4 and ≥5 (pH holding time ratios; HTRs) and mean gastric pH. Acid-inhibitory effect (pH4 HTR) of vonoprazan was significantly greater than that of esomeprazole or rabeprazole on both Days 1 and 7; Day 7 difference in pH4 HTR for vonoprazan vs. esomeprazole was 24.6% [95% confidence interval (CI): 16.2-33.1] and for vonoprazan vs. rabeprazole 28.8% [95% CI: 17.2-40.4]. The Day 1 to Day 7 ratio of 24-h pH4 HTRs was >0.8 for vonoprazan, compared with 0.370 for esomeprazole and 0.393 for rabeprazole. Vonoprazan was generally well tolerated. One vonoprazan subject withdrew due to a rash which resolved after discontinuation. This study demonstrated a more rapid and sustained acid-inhibitory effect of vonoprazan 20 mg vs. esomeprazole 20 mg or rabeprazole 10 mg. Therefore, vonoprazan may be a potentially new treatment for acid-related diseases. © 2015 The Authors. Alimentary Pharmacology & Therapeutics published by John Wiley & Sons Ltd.