Laboratory Analysis Of Samples Research Articles

Assessing leaf spectral properties of Phragmites australis impacted by acid mine drainage

The decanting of acid mine drainage (AMD) from the Western Basin on the Witwatersrand in late 2010 raised concerns about AMD risks in other gold, coal and copper mining areas of South Africa. Field spectroscopy and the use of vegetation indices could offer an affordable and easy means of monitoring the impact of mine water and/or AMD on vegetation. The impact of raw and treated mine water or contaminated soil on wetland vegetation often manifests in growth inhibition and reduction of foliar pigments and nutrient levels. Surveying the impact on wetland vegetation or underlying soils can be difficult and expensive considering the cost of laboratory analysis of samples. The potential of field spectroscopy for detecting the impact of mine water on wetland vegetation was examined by assessing (1) whether there was a significant difference in leaf spectra between sites receiving mine water and a non-impacted control site and (2) whether there was a gradation of vegetation condition downstream from the decanting site. Two vegetation indices were derived from portable field spectrometer-measured spectra of five green leaves of Phragmites australis – the chlorophyll red edge position (REP) and the normalised difference vegetation index (NDVI) – for two dormant (winter) and peak growth (summer) seasons in 2011–2012. Mean REP and NDVI values were significantly (p<0.05) lower for affected sites compared to the control site for both seasons and years. The range of REP values for young green leaves in winter for affected sites was 695–720 nm compared to the narrower range of 705–721 nm for the control site. The mean REP values for young green leaves in winter was 708 nm for the affected sites compared to 716 nm for the control site. The downstream gradation, however, fluctuated for REP and NDVI over the study period. We conclude that field spectroscopy shows potential to serve as a relatively quick and affordable means to assess the condition and health of vegetation affected by AMD.

A New Analytical Q-Absorbance Ratio Method Development and Validation for Simultaneous Estimation of Lamivudine and Isoniazid

A new UV spectrophotometric absorption ratio method was developed and validated for the simultaneous estimation of lamivudine and isoniazid. The method involved Q-absorption ratio analysis using two wavelengths, with one being the λmax of lamivudine (272 nm, λ2) and the other being the isoabsorptive point of both drugs (246 nm, λ1). Beer’s law was obeyed in the concentration range between 5 and 30 µg/mL for both lamivudine and isoniazid. The results of analysis have been validated statistically and by recovery studies as per ICH guidelines. The accuracy ranged between 99.65 and 101.91% and Sandell’s sensitivity ranged between 0.0229 and 0.0347 µg/cm2. The method was found to be simple, precise, reproducible, rapid, and economical. Hence, it could be used in the analysis of laboratory samples and marketed formulations containing these two drugs in the future.

Carbon and Nitrogen Flow in the Traditional Land Use System of the Himalaya Region, Nepal

Traditionally, agricultural systems in the Himalayan region of Nepal rely on livestock, forestry, and crop production. The extraction of litter, tree fodder, and grasses from the forest ensures a net movement of carbon (C) and nitrogen (N) from the forest to the agricultural land. This study assessed the sustainability of farming systems by computing the C and N input and output of the agroecosystem. The study was conducted in the buffer zone of Sagarmatha National Park in Nepal. A questionnaire survey, field measurements, and laboratory analysis of samples were used to determine the C and N inputs and fluxes in the systems. Forest litter is a major source of C and N for agricultural land, as is fodder from the forest fed to livestock (lopping of trees, grazing). Amounts that are fairly significant are supplied by human waste. To produce the average amount of 40 kg N ha−1 per year applied as compost, 25 kg N from forest litter, 23 kg N from forest fodder, 9 kg N from human waste, and 3.5 kg N from field grazing and straw are required. Losses are attributed to volatilization, denitrification, and leaching. Harvest residues amount to 14 kg N ha−1. Rather than discouraging the use of litter toilets, a modernized version of indigenous waste management and composting practices could reduce dependency on forests for fuelwood, fodder, and litter. To maintain the present fertility status, each household needs an estimated 2–5 ha of forest land.

Outcome Risk Factors during Respiratory Infections in a Paediatric Ward in Antananarivo, Madagascar 2010–2012

BackgroundAcute respiratory infections are a leading cause of infectious disease-related morbidity, hospitalisation and mortality among children worldwide, and particularly in developing countries. In these low-income countries, most patients with acute respiratory infection (ARI), whether it is mild or severe, are still treated empirically.The aim of the study was to evaluate the risk factors associated with the evolution and outcome of respiratory illnesses in patients aged under 5 years old.Materials and MethodsWe conducted a prospective study in a paediatric ward in Antananarivo from November 2010 to July 2012 including patients under 5 years old suffering from respiratory infections. We collected demographic, socio-economic, clinical and epidemiological data, and samples for laboratory analysis. Deaths, rapid progression to respiratory distress during hospitalisation, and hospitalisation for more than 10 days were considered as severe outcomes. We used multivariate analysis to study the effects of co-infections.ResultsFrom November 2010 to July 2012, a total of 290 patients were enrolled. Co-infection was found in 192 patients (70%). Co-infections were more frequent in children under 36 months, with a significant difference for the 19–24 month-old group (OR: 8.0).Sixty-nine percent (230/290) of the patients recovered fully and without any severe outcome during hospitalisation; the outcome was scored as severe for 60 children and nine patients (3%) died.Risk factors significantly associated with worsening evolution during hospitalisation (severe outcome) were admission at age under 6 months (OR = 5.3), comorbidity (OR = 4.6) and low household income (OR = 4.1).ConclusionCo-mordidity, low-income and age under 6 months increase the risk of severe outcome for children infected by numerous respiratory pathogens. These results highlight the need for implementation of targeted public health policy to reduce the contribution of respiratory diseases to childhood morbidity and mortality in low income countries.

Research Methods and Experimental Design Influence on Surface Soil Properties in Steppe Area of Northern China Wind Power Field

There is a close relationship between the disturbance of wind power generation on the circulation of the atmosphere and the underlying surface soil properties change process. Research mentality and the technical route of the wind power impact on surface soil properties were discussed in detail. With the wind rods with different construction time as the center, outward in a separated by 20m as the radius to make concentric circular sample ,differences could be obtained between eight neighboring direction and the same direction in different years and different distance on soil properties. Methods,field investigation, sampling and laboratory analysis of samples of combining,were applied. Data were analyzed using ORIGIN and SPSS software. Practice has proved that this set of research methods and experimental design is feasible.

Use of Scanning Near-Infrared Spectroscopy as a Quality Control Indicator for Bulk Blended Inorganic Fertilizers

The use of bulk blended fertilizers worldwide has become preferred to compounded chemical fertilizers. This poses new problems in obtaining a representative sample for laboratory analysis. There are huge variations in particle-size distribution, shape of particles, and bulk density. These factors results in separation when attempting to obtain smaller subsamples. Turnaround time of wet chemical analysis by the laboratories (usually 1–2 weeks) further compounds the problem. A procedure was developed to obtain reliable composition results for quality control of bulk blend fertilizers using near-infrared spectroscopy (NIRS) technology. Results are available immediately. Another challenge is obtaining reliable chemical analyses for preparing the NIRS calibrations. To overcome this, an exact formulation is prepared in the laboratory using the raw materials. The size of each such mixture (approximately 500 g) is sufficient to allow the complete sample to be scanned on a scanning NIRS instrument with rotating sample container. All raw materials are also scanned individually. Robust calibrations were obtained in this manner, and special control systems were implemented to ensure and verify the reliability of the results. The results of the NIRS were shown to be acceptable and on par with the chemical composition for the following elements: nitrogen (N), phosphorus (P), potassium (K), and sulfur (S). Better results were obtained for N if separate calibrations were prepared for N sources (urea, ammonium, and nitrate). The best results for all components were obtained using Partial Least Squares (PLS) chemometrics with Standard Normal Variant (SNV) Detrend Pathlength correction and wavelengths between 950 and 1650 nm. Calibrations for other parameters are in process.

Detection of hydrocarbons in clay soils: A laboratory experiment using spectroscopy in the mid- and thermal infrared

Remote sensing has been used for direct and indirect detection of hydrocarbons. Most studies so far focused on indirect detection in vegetated areas. We investigated in this research the possibility of detecting hydrocarbons in bare soil through spectral analysis of laboratory samples in the short wave and thermal infrared regions. Soil/oil mixtures were spectrally measured in the laboratory. Analysis of spectra showed development of hydrocarbon absorption features as soils became progressively more contaminated. The future application of these results airborne seems to be a challenge as present and future sensors only cover the diagnostic regions to a limited extent.

Pork Implicated in a Shiga Toxin-producing Escherichia coli O157:H7 Outbreak in Ontario, Canada

To describe an outbreak of Shiga toxin-producing Escherichia coli (STEC) O157:H7 infection following a four-day family gathering in Ontario. This is the first published account of a STEC O157 outbreak in Canada linked to consumption of pork. The outbreak investigation included interviews with food handlers and other key associated persons, inspection of food preparation premises, traceback investigations, case finding, analysis of data from an outbreak questionnaire, and laboratory analysis of samples collected from various sources associated with the outbreak. Several meals, including pork from a pig roast, were served to the 59 attendees, 29 of whom developed gastrointestinal illness following the event. Six cases developed bloody diarrhoea and seven were hospitalized. Leftover pork served the day after the pig roast was the item most significantly associated with an increased risk of illness (p<0.001). STEC O157:H7 was isolated from 11 of the 29 ill attendees, and also from the pork. By pulse-field gel electrophoresis (PFGE), all STEC O157:H7 pork isolates were either identical or closely related to the 11 clinical isolates. No STEC was detected in any other samples. Three Clostridium perfringens isolates, unrelated by PFGE, were obtained from two STEC-positive cases and the pork. This outbreak highlights the need for increased awareness of pork as a potential source of STEC O157 infection, and for enhanced education regarding the safe handling, cooking and storage of food, specifically where large cuts of meat are cooked outdoors at events such as pig roasts, a cultural norm in some communities.

Accuracy of perception of ovulation day in women trying to conceive

Background:The likelihood of conception is increased if intercourse is timed to coincide with the fertile period (5 days up to ovulation). However, to be effective, this requires good awareness of the day of ovulation. The aim of this study was to examine the accuracy of women’s perceived ovulation day, compared with actual fertile days, in a cohort of women trying to conceive.Main outcome measures:Comparison of women’s estimated day of ovulation with their actual ovulation day (determined by detecting luteinising hormone).Methods:This was a sample collection study and volunteer women were recruited via online advertising. At recruitment volunteers reported the cycle day they believed they ovulated. They then used a home urine fertility monitor to test their daily fertility status to time intercourse to try and achieve conception, in addition to collecting early morning urine samples for laboratory analysis. The main outcome measure was a comparison of women’s estimated day of ovulation with their actual ovulation day, as determined by urine detection of luteinising hormone.Results:Three hundred and thirty women were recruited onto the study and data was available for 102 volunteers who became pregnant. Thirteen women (12.7%) correctly estimated their ovulation day; median difference +2 days, range −10 to +27 days. The most common days for estimation of ovulation were day 14 (35.5%) and day 15 (15.7%). Only 55% of estimated ovulation days fell within the volunteers’ fertile window; only 27% on days of peak fertility.Conclusions:Women trying to conceive may benefit from using a prospective method to identify their fertile phase, as a significant proportion could be incorrectly estimating their fertile days. These observations were made on women who were actively looking for knowledge on fertility and considered only cycles where conception occurred, inaccuracy could be greater if a broader population is considered.

Biogeochemical characterization of a lithified paleosol: Implications for the interpretation of ancient Critical Zones

Modern soils are characterized by an array of physical, chemical, mineralogical, and biological laboratory analyses of samples taken from horizons of pedogenic profiles. In contrast, fossil soils (paleosols) are typically characterized from assays of whole-rock molecular oxides because of sample lithification where element sources are unconstrained. Here we for the first time subject a lithified paleosol to an array of modern soil analytical techniques and new pedotransfer functions, providing a glimpse into the colloidal world of an ancient Critical Zone as an analog to research conducted on a network of modern Critical Zones. This methodology provides a framework for decoding a previously unknown archive of terrestrial biogeochemical information at multiple temporal and spatial scales. Application to a paleosol within an early Paleocene Critical Zone reveals that many biogeochemical properties have been preserved since burial that are similar to modern clay-rich, Vertisols. The measured and calculated physical properties of this paleosol include clay content and mineralogy, bulk density and water retention, available water capacity, and coefficient of linear extensibility (shrink–swell potential). The chemical properties include cation exchange capacity, exchangeable cations, base saturation, and exchangeable sodium percentage. The solution properties electrical conductivity and pH seem reasonable, but are interpreted with less confidence because of their greater vulnerability to alteration from fluid flow. New pedotransfer functions to reconstruct pre-burial organic carbon and nitrogen contents provide invaluable information of organically-derived nutrient content. The sum of the measured properties of the early Paleocene paleosol in context of reconstructed regional environmental conditions indicate the presence of a mid-successional hardwood forest in a humid climate with high water holding capacity, high nutrient retention, and rapid flux of elements through biogeochemical cycling.

Stanje zagađenosti vazduha u odnosu na pojedine parametre za grad Kragujevac u periodu od 1999. do 2008. godine kao jednog od faktora rizika za nastanak HOBP

Air is one of the most important segments of environment which, with the expansion of industry and traffic, became polluted with ingredients which are harmful for man and his environment. There are many sources of airpollution in Sumadija and Western Serbia. They endanger health of everyone, and specially of most sensitive parts of population (pregnant women, children, old and sick people). Institute of public health in Kragujevac has been following the quality of air for many years already. The control of quality of air includes: • research of emission on defined emitters(sampling, laboratory analysis of samples and obtaining of expert opinion) and • research of immission (systematic following of immission of basic and specific damaging substances which come from stationary resources and the control of quality of air which comes from exhaust gases from motor vehicles, including sampling, laboratory analysis of samples and obtaining of expert opinion. Regular, continuous control of quality of air (immission measurements) are made on territory of City of Kragujevac through following essential damaging substances, sulfur dioxide, nitric oxides, soot and all sedimentary substances since the year 1975. Researches in world and in our country show that specific damaging substances from air which are of organic source as well as suspended substances do have special influence on health of people whether they directly cause disease deterioration of already existing diseases of respiratory organs or cause allergic manifestations which lead to chronic disinfectuous respiratary diseases (ICD - 10; J42 - J45). This group of diseases includes chronic obstructive lungs disease (ICD - 10; J42 - J44) and asthma (ICD - 10; J45). In world 400 million of people live with the diagnosis of chronic disinfectuous respiratory diseases, and among them are 320 million with chronic obstructive respiratory disease. Serbia is on the fourth place according to the level of dieing from chronic disinfectuous respiratory diseases after Kirgistan (99,0%), Kazachtan (56,5%), and Moldavy (51,9%). By analytical study that has been done by Institute of public health in Kragujevac it is estimated that there is increase of level of mortality from chronic disinfectuous respiratory diseases in Sumadija for 27% (from 19,48% in 1998. to 24,77% in 2008.). Average mortality rate for both sexes has higher values on the territory of Sumadija district than in Serbia (for men in Sumadija the mortality rate from chronic disinfectuous respiratory diseases is 38,4% while for men in Serbia this rate is somewhat lower - 37,15%; for women in Sumadija this mentioned mortality rate is 15,05% and is higher than for women in Sebia - 14,14%). Our study confirms the high degree of correlation between certain parameters of air pollution with mortality from chronic obstructive pulmonary disease.

Improving copper matte grade control in a concentrate flash furnace

The copper matte grade (CMG) variation in a flash furnace depends on bath temperature, phase levels, ratio of oxygen to sulfur, iron and copper content on the feed, and tonnage ratio of silica flux and feed, among others. The CMG is obtained from laboratory analysis of samples taken when the matte is tapped out from the furnace. Then the CMG is known with a time delay of 1–2 hours, almost every one hour. Since feed characteristics usually change during this period, any feedback control of CMG cannot reduce enough the grade variability. On the other hand, it was shown that main disturbances are coming with the composite feed tonnage and composition, being the powder tonnage control system the main contribution. A new calibration system was proposed and implemented. During an evaluation period of 60 days, it was found that the standard deviation of the CMG was reduced in 25%. This improvement can be explained considering two effects. First, the stabilization of the total feed tonnage that affect the mass balance in the furnace. Second, even when the powder tonnage is only 7% of the total tonnage, its special chemical composition contributed to increase the copper content in the matte. The stabilization of the furnace operation also improved the phase separation, as well as reduced the variance of the gas SO2 composition and flow rate. The operators took advantage of this reduced variability to increase the fusion rate and thus the mean generated gas flow rate in the furnace, without violating the plant constraints.One important conclusion is that this result will permit to increase the average value of CMG, when the development of the virtual sensor of feed composition is completed and when this estimation becomes part of a FF-FB control.

Geophysical investigation of barite deposit in Tunga, Northeastern Nigeria

Gravity and electromagnetic methods were combined to characterize known veins and possibly unveil other concealed veins in Tunga, Northeastern Nigeria. Barite occurs in the study area as vein deposits hosted in clean sandstone rocks. Laboratory analyses of samples show average specific gravity of the variety to vary between 3.16 and 4.24 while the host sandstone rock is 2.63. The study is focused on an area of 0.5 km2 measuring 1.0 km in the strike and 0.5 km in the dip (designated X1 to X6 in northwest-southeast azimuth) which appears as the most promising terrain in barite prospectivity. Relatively high Bouguer anomalies were recorded over regions that are presumably underlain by barites. Barite mineralization potential varies from high with gravity values of between 177.507 and 181.072 mGals around western flanks of Traverses X2 and X3 to medium values (174.681 and 176.801 mGals) around central areas of Traverse X3. Areas of low Bouguer anomaly were presumably barren (X1, X4, X5, and X6). The variations in the Bouguer anomaly values are presumably influenced by the density contrast between the barite and the host rocks. Areas of high gravity values exhibit very low conductivity values (< 10 mS/m) and are presumed underlain by dense materials of low conductivity to which barite mineralization can be associated. Thus, in this study, areas of high gravity values accompanied by low conductivities on the western/southwestern flank of the prospect around Traverses X2 and X3 are associated with barite mineralization. The trend of mineralization in the area is southwest-wards in the direction of River Benue. Thus, higher barite mineralization potential probably exists beneath River Benue and its southern flank in Tunga area. Key words: Barite, vein, bouguer anomaly, conductivity, mineralization.

Neutron Activation Analysis of a Particle Returned from Asteroid Itokawa

A single grain (~3 micrograms) returned by the Hayabusa spacecraft was analyzed by neutron activation analysis. This grain is mainly composed of olivine with minor amounts of plagioclase, troilite, and metal. Our results establish that the Itokawa sample has similar chemical characteristics (iron/scandium and nickel/cobalt ratios) to chondrites, confirming that this grain is extraterrestrial in origin and has primitive chemical compositions. Estimated iridium/nickel and iridium/cobalt ratios for metal in the Itokawa samples are about five times lower than CI carbonaceous chondrite values. A similar depletion of iridium was observed in chondrule metals of ordinary chondrites. These metals must have condensed from the nebular where refractory siderophile elements already condensed and were segregated.

Oxygen Isotopic Compositions of Asteroidal Materials Returned from Itokawa by the Hayabusa Mission

Meteorite studies suggest that each solar system object has a unique oxygen isotopic composition. Chondrites, the most primitive of meteorites, have been believed to be derived from asteroids, but oxygen isotopic compositions of asteroids themselves have not been established. We measured, using secondary ion mass spectrometry, oxygen isotopic compositions of rock particles from asteroid 25143 Itokawa returned by the Hayabusa spacecraft. Compositions of the particles are depleted in (16)O relative to terrestrial materials and indicate that Itokawa, an S-type asteroid, is one of the sources of the LL or L group of equilibrated ordinary chondrites. This is a direct oxygen-isotope link between chondrites and their parent asteroid.

Irradiation History of Itokawa Regolith Material Deduced from Noble Gases in the Hayabusa Samples

Noble gas isotopes were measured in three rocky grains from asteroid Itokawa to elucidate a history of irradiation from cosmic rays and solar wind on its surface. Large amounts of solar helium (He), neon (Ne), and argon (Ar) trapped in various depths in the grains were observed, which can be explained by multiple implantations of solar wind particles into the grains, combined with preferential He loss caused by frictional wear of space-weathered rims on the grains. Short residence time of less than 8 million years was implied for the grains by an estimate on cosmic-ray-produced (21)Ne. Our results suggest that Itokawa is continuously losing its surface materials into space at a rate of tens of centimeters per million years. The lifetime of Itokawa should be much shorter than the age of our solar system.

Incipient Space Weathering Observed on the Surface of Itokawa Dust Particles

The reflectance spectra of the most abundant meteorites, ordinary chondrites, are different from those of the abundant S-type (mnemonic for siliceous) asteroids. This discrepancy has been thought to be due to space weathering, which is an alteration of the surfaces of airless bodies exposed to the space environment. Here we report evidence of space weathering on particles returned from the S-type asteroid 25143 Itokawa by the Hayabusa spacecraft. Surface modification was found in 5 out of 10 particles, which varies depending on mineral species. Sulfur-bearing Fe-rich nanoparticles exist in a thin (5 to 15 nanometers) surface layer on olivine, low-Ca pyroxene, and plagioclase, which is suggestive of vapor deposition. Sulfur-free Fe-rich nanoparticles exist deeper inside (<60 nanometers) ferromagnesian silicates. Their texture suggests formation by metamictization and in situ reduction of Fe(2+).

Three-Dimensional Structure of Hayabusa Samples: Origin and Evolution of Itokawa Regolith

Regolith particles on the asteroid Itokawa were recovered by the Hayabusa mission. Their three-dimensional (3D) structure and other properties, revealed by x-ray microtomography, provide information on regolith formation. Modal abundances of minerals, bulk density (3.4 grams per cubic centimeter), and the 3D textures indicate that the particles represent a mixture of equilibrated and less-equilibrated LL chondrite materials. Evidence for melting was not seen on any of the particles. Some particles have rounded edges. Overall, the particles' size and shape are different from those seen in particles from the lunar regolith. These features suggest that meteoroid impacts on the asteroid surface primarily form much of the regolith particle, and that seismic-induced grain motion in the smooth terrain abrades them over time.

Itokawa Dust Particles: A Direct Link Between S-Type Asteroids and Ordinary Chondrites

The Hayabusa spacecraft successfully recovered dust particles from the surface of near-Earth asteroid 25143 Itokawa. Synchrotron-radiation x-ray diffraction and transmission and scanning electron microscope analyses indicate that the mineralogy and mineral chemistry of the Itokawa dust particles are identical to those of thermally metamorphosed LL chondrites, consistent with spectroscopic observations made from Earth and by the Hayabusa spacecraft. Our results directly demonstrate that ordinary chondrites, the most abundant meteorites found on Earth, come from S-type asteroids. Mineral chemistry indicates that the majority of regolith surface particles suffered long-term thermal annealing and subsequent impact shock, suggesting that Itokawa is an asteroid made of reassembled pieces of the interior portions of a once larger asteroid.

Global Questions, Local Answers: Soil Management and Sustainable Intensification in Diverse Socioeconomic Contexts of Cuba

In the complex context of global food and agricultural systems, research in agriculture must respond to multidisciplinary questions of economic development, ecological sustainability and food justice. With the objective of responding to several of the most important questions facing agriculture today, this article describes recent research in three Cuban cropping systems: state farms, cooperatives, and small family farmers. Soil management is considered here as a crux of human intervention in agroecosystems, capable of determining the impacts of productive activities upon agricultural and ecosystem functions. Management practices commonly used in each farm system are evaluated using two systems of indicators, one for technological quality and one for agricultural intensification. Soil physical quality is characterized through laboratory analysis of samples taken in the same type of soil under long-term production in state, cooperative, and family farmer cropping systems. Soil structure management in the small farmer system is especially worthy of study, because this agricultural system has developed an intensive agroecological productive model on the basis of low external input use, polycultures and internal nutrient cycling. Favorable policies and farmer organizations are discussed as indispensible elements of sustainable agricultural development. The relationships between soil management, local knowledge, and food access are explored in the Cuban context and as directions for food system studies.