Bacitracin Determination in Feeds: Evaluation of Methods

1981 ◽  
Vol 64 (4) ◽  
pp. 980-990
Author(s):  
Hussein S Ragheb
Keyword(s):  
Contributing Factors ◽  
Plate Method ◽  
Large Variability ◽  
Collaborative Studies ◽  
Different Types ◽  
Test Organisms ◽  
Sources Of Variation ◽  
Zinc Bacitracin ◽  
Many Sources ◽  
Evaluation Of Methods

Abstract Assay of bacitracin activity in feeds is subject to many sources of variation. Bacitracin standards are complex mixtures and may contain various amounts of less active forms of bacitracin. Test organisms may respond differently to these mixtures. Collaborative studies should involve the use of one standard, perhaps USP zinc bacitracin. The use of different types of bacitracin standards (regular or zinc) in a laboratory may contribute to variation in sample potency. The pyridine extraction method is subject to serious operational difficulties. Among the contributing factors are incomplete evaporation of pyridine (causing positive bias), allowing the temperature to increase too much during evaporation (causing negative bias), and the numerous manipulative steps in the technique (causing large variability). Because of these factors and the toxic properties of pyridine, the method finds little use. Methanol extraction offers a better substitute for determining zinc or methylene disalicylate bacitracin in premixes and complete feeds by the plate method.

Antioxidants (BHA and BHT) in Breakfast Cereals

1965 ◽  
Vol 48 (4) ◽  
pp. 694-699
Author(s):  
David M Takahashi
Keyword(s):  
Gas Chromatography ◽  
Petroleum Ether ◽  
Chromatographic Method ◽  
Steam Distillation ◽  
Gas Chromatograph ◽  
Breakfast Cereals ◽  
Collaborative Studies ◽  
Different Types ◽  
Gas Chromatographic Method

Abstract Antioxidants (BHA and BHT) in different types of breakfast cereals were studied by argon ionization gas chromatography. Samples containing antioxidants were packed into the column, and antioxidants were eluted with redistilled petroleum ether. EIuates were concentrated under N2 and injected into a Barber-Colman Model 10 gas chromatograph. Recoveries ranged from about 92 to 110%. Results obtained by steam distillation-colorimetry methods were erratic. Colorimetric procedures were not free from interferences and could lead to highly erroneous results at the lower ppm levels. The gas chromatographic method is faster, simpler, and more accurate. Collaborative studies on corn and rice ready-to-eat breakfast cereals are recommended.

scholarly journals Transport of engineered nanoparticles in soils and aquifers

2019 ◽  
Vol 27 (1) ◽  
pp. 43-70 ◽  
Author(s):  
Mahmood Fazeli Sangani ◽  
Gary Owens ◽  
Amir Fotovat
Keyword(s):  
Experimental Studies ◽  
Engineered Nanoparticles ◽  
Background Solution ◽  
Contributing Factors ◽  
Factors Affecting ◽  
Soil Systems ◽  
Aquifer Systems ◽  
Different Types ◽  
Transport Behaviour ◽  
The Media

Transport and deposition behaviour of engineered nanoparticles (ENPs) in natural aquifers and soil systems is a key determinant of the fate of these materials in environmental systems. A growing number of experimental studies are being conducted worldwide to address transport and deposition of ENPs in porous media (PM). Here we comprehensively review the main mechanisms and factors affecting the mobility of the environmentally important ENPs in natural PM. A variety of different processes including those that promote mobility and result in elution from the PM and those that hinder their mobility and promote ENP retention can influence ENP’s mobility through soil and aquifer media. The most important contributing factors regarding ENP transport in PM include: the physicochemical properties of the ENP, the media, the hydrodynamics of the system, and the background solution characteristics. Results from several studies conducted on the most common and environmentally important ENPs have shown that under natural environmental conditions, different types of ENPs show different transport behaviour in soil and aquifer systems. Additionally, the importance of media matrix and mobile solution factors in governing mobility of ENPs varies from one type of ENP to another.

Examining and comparing observed and simulated daytime neutral wind and ionospheric drift variations

2021 ◽  
Author(s):  
Astrid Maute ◽  
Brian Harding ◽  
Joanne Wu ◽  
Colin Triplett ◽  
Rodrick Heelis ◽  
...  
Keyword(s):  
Climate Model ◽  
Middle Latitude ◽  
General Context ◽  
Neutral Wind ◽  
Contributing Factors ◽  
Low Latitude ◽  
Large Variability ◽  
Ion Drift ◽  
Plasma Drift ◽  
Ionospheric Drift

<p>The neutral wind dynamo plays an important role in generating low-latitude ionospheric variability and space weather. The characteristic equatorial ionization anomaly is generated by the daytime equatorial upward drift, which has imprinted on it the variation from upward propagating tides and waves. Observations and modeling studies have indicated large variability of the plasma drift on time scales from days to seasons associated with the wind dynamo at low and middle latitudes. The relationship of the ionospheric drift variability to the neutral wind variations is still not fully understood. The Ionospheric Connection explorer (ICON) mission is designed to focus on the low to middle latitude region and measures key parameters, such as the plasma drift and density and neutral temperatures and winds, to address the question of vertical coupling.</p><p>In this presentation, we will focus on the ICON observations and compare to Whole Atmosphere Community Climate Model-Extended (WACCM-X) simulations to examine the daytime low latitude ion drift and neutral wind variations. We investigate the day-to-day and longitudinal variation between concurrent ion drift and neutral wind variations over short time periods to quantify the contribution of the neutral wind in generating the ionospheric drift variations. Employing WACCM-X simulations, we investigate the importance of contributing factors, such as ionospheric conductivities, the geomagnetic main field, magnetosphere-ionosphere coupling, and the neutral wind, in generating the observed ionospheric drift variations. While we focus in this study on field line integrated ionospheric current density due to electric field/drift and neutral wind, we conclude by discussing our results in a more general context.</p>

scholarly journals Identification of Sources of Inter-Laboratory Variation in Factor VIII Assay

1977 ◽  
Author(s):  
T.B.L. Kirkwood ◽  
C.R. Rizza ◽  
T.J. Snape ◽  
I. Rhymes ◽  
D.E.G. Austen
Keyword(s):  
Factor Viii ◽  
Systematic Difference ◽  
Normal System ◽  
Two Stage ◽  
Initial Dilution ◽  
One Stage ◽  
Collaborative Studies ◽  
Freeze Dried ◽  
Sources Of Variation ◽  
The One

A repeated finding of national and international collaborative studies of standard Factor VIII preparations has been that systematic differences exist between laboratories in their measurement of the relative activities of the same pairs of Factor VIII preparations.A workshop meeting was held at the Oxford Haemophilia Centre (England) during 23rd-26th November 1976 to investigate which of the possible sources of variation between laboratories were responsible. Participants from 16 British laboratories (9 one-stage, 7 two-stage) performed a total of 273 assays using three freeze-dried preparations of differing purity (a plasma, an intermediate and a high purity concentrate). The results of assays with each participant using their normal system established that, if the participants were a representative cross-section, approximately one-third of one-stage laboratories would show a systematic difference from the overall mean of at least 16%, with a similar figure for the two-stage laboratories of 9%. Various features of the assay systems were then modified in a controlled series of experiments. The results showed conclusively that i) differences between reagents accounted for most of the variation between laboratories and, ii) the two-stage assays were, on average, detecting relatively more activity in the more purified preparations than the one-stage assays. The results also suggested that the use of buffer as opposed to haemophilic plasma for the initial dilution of concentrates did not affect the assay results.

scholarly journals Mitigating Effects of Climate Change and Deforestation on Bees With Respect to Their Ecology and Biology

2015 ◽  
Vol 6 (2) ◽  
pp. 1
Author(s):  
Musiliyu Oladipupo Mustafa ◽  
Olubusola Temitope Adeoye ◽  
Folorunso Ishaq Abdulalzeez ◽  
Olukayode Dare Akinyemi
Keyword(s):  
Climate Change ◽  
Forest Ecosystems ◽  
Royal Jelly ◽  
Global Climate ◽  
Tropical Rainforests ◽  
Contributing Factors ◽  
Honey Production ◽  
The World ◽  
Different Types ◽  
Populous Country

<p>Deforestation occurs around the world; though tropical rainforests are particularly targeted, it is considered to be one of the contributing factors to global climate change. While Nigeria is probably best known today for its oil deposits, according to the World Resources Institute, Nigeria is home to 4,715 different types of plant species, and over 550 species of breeding birds and mammals, making it one of the most ecologically vibrant places of the planet. It is also one of the most populous country with appalling deforestation record. This situation is hence making our ecosystems, biodiversity, agriculture and other natural endowments highly unsecured. The Forest provides excellent resources for bees and beekeeping, and bees are a vital part of forest ecosystems. Bees are essential for sustaining our environment because they</p><p>Pollinate flowering plants and conserves biological biodiversity along with their products (honey, propolis, bee wax, royal jelly and bee venom) which are beneficial to man. Conservation of the forest is therefore imperative for sustainable beekeeping. The study reviews the different causes of climate change and how they affect different natural forest activities which are weather-dependent. Also how climate change and other causes (both natural and man-made) lead to deforestation, which in turn distort sustainable honey production in Nigeria. Different sustainable measures hoped to alleviate the effects of climate change and deforestation where also discussed. </p>

scholarly journals In Vitro Techniques Using the DaisyII Incubator for the Assessment of Digestibility: A Review

Animals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 775 ◽  
Author(s):  
Sonia Tassone ◽  
Riccardo Fortina ◽  
Pier Giorgio Peiretti
Keyword(s):  
Performance Metrics ◽  
Rumen Fluid ◽  
In Vitro Digestibility ◽  
In Vitro Techniques ◽  
Different Types ◽  
Technology Corporation ◽  
Sources Of Variation ◽  
Source Sample ◽  
Precision And Accuracy

This review summarises the use of the Ankom DaisyII incubator (ADII; Ankom Technology Corporation Fairport, NY, USA), as presented in studies on digestibility, and its extension to other species apart from ruminants, from its introduction until today. This technique has been modified and adapted to allow for different types of investigations to be conducted. Researchers have studied and tested different procedures, and the main sources of variation have been found to be: the inoculum source, sample size, sample preparation, and bag type. In vitro digestibility methods, applied to the ADII incubator, have been reviewed, the precision and accuracy of the method using the ADII incubator have been dealt with, and comparisons with other methods have been made. Moreover, some hypotheses on the possible evolutions of this technology in non-ruminants, including pets, have been described. To date, there are no standardised protocols for the collection, storage, and transportation of rumen fluid or faeces. There is also still a need to standardise the procedures for washing the bags after digestion. Moreover, some performance metrics of the instrument (such as the reliability of the rotation mechanism of the jars) still require improvement.

scholarly journals Clinical practice guidelines: on what evidence is our clinical practice based?

1996 ◽  
Vol 20 (6) ◽  
pp. 363-366 ◽  
Author(s):  
Sarah Marriott ◽  
Claire Palmer
Keyword(s):  
Experimental Data ◽  
Clinical Practice ◽  
Practice Guidelines ◽  
Recent Progress ◽  
Work Group ◽  
Clinical Settings ◽  
Literature Reviews ◽  
Different Types ◽  
Research Findings ◽  
Many Sources

Many sources of evidence inform clinical practice, including research findings, patients' views, and clinical experience. This article describes recent progress in developing what will be the College's first guideline, The Assessment and Management of Violence In Clinical Settings. The design of the programme acknowledges the diversity of evidence in this area, by drawing a distinction between different types of evidence. Evidence is systematically identified and its quality appraised by the Work Group, through commissioning literature reviews. Initial recommendations will be based on experimental data. The methods used to consider non-experimental data, particularly expert opinion, will be described in more detail in a later article in this series.

scholarly journals Differences in the Climatological Characteristics of Precipitation between Active and Break Spells of the Indian Summer Monsoon

2016 ◽  
Vol 29 (21) ◽  
pp. 7797-7814 ◽  
Author(s):  
T. Narayana Rao ◽  
K. Saikranthi ◽  
B. Radhakrishna ◽  
S. Vijaya Bhaskara Rao
Keyword(s):  
Spatial Distribution ◽  
Indian Summer Monsoon ◽  
Diurnal Cycle ◽  
East Coast ◽  
Large Variability ◽  
Late Night ◽  
The Core ◽  
High Prevalence ◽  
Different Types ◽  
Evening Peak

Abstract Climatological characteristics of precipitation during the active and break spells of the monsoon are studied using 15 years of TRMM measurements. The spatial variation of rain fraction suggests that most of the seasonal rainfall occurs in spells of active monsoon over India, except for the zones along the east coast. The broader reflectivity distribution at higher altitudes and larger average storm height during active spells indicate the high prevalence of deep systems during this spell. The spatial distribution of the occurrence and fraction of different types of rain exhibits large variability from land to ocean and between the spells. The higher occurrence and fraction of stratiform rain during the active spell, particularly over the core monsoon zone, is due to the prevalence of organized mesoscale systems with large stratiform portions. The break spells are characterized by higher occurrence of shallow rain and larger fraction of convective rain. While an evening peak is observed over land during the break spell, the phase of the diurnal cycle exhibits large spatial variability during the active spell. The rainfall peaks from late night to midnight in southeastern India and in the morning near the foothills of the Himalayas during the active spell. The diurnal and semidiurnal components together explain more than 90% of total variance over many of the zones during both spells. The observed differences in precipitation between the spells are discussed in light of the differences in synoptic- and mesoscale mechanisms responsible for the production of precipitation.

scholarly journals Study of Antibacterial Activity of Chenopodium album Leaves Extract

2018 ◽  
Vol 10 (01) ◽  
Author(s):  
Kaur M. ◽  
Sharma S. ◽  
Garg S. ◽  
Arora M.
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Bacillus Subtilis ◽  
Chenopodium Album ◽  
Antibacterial Activities ◽  
Maximum Activity ◽  
Zone Of Inhibition ◽  
Plate Method ◽  
E Coli ◽  
Test Organisms

This study describes the antibacterial activities of three different solvent extracts of leaves of Chenopodium album. Methanol, acetone and chloroform extracts of C. album were prepared. The antibacterial activity was assessed using well plate method and were examined for the size of zone of inhibition. Different extracts were investigated against the test organisms namely Lactobacillus, Bacillus subtilis and Escherichia coli. The maximum activity was observed at 100% concentration of different extracts of leaves. The maximum zone of inhibition for 100% concentration were observed as E. coli (19 mm) and Lactobacillus (19 mm) in diameter respectively. C. album did not show any antibacterial activity against B. subtilis. Antibacterial activity was compared with standard Amoxicillin and it was found to be 23 mm diameter for Lactobacillus and 25 mm for both E. coli and B. subtilis in terms of zone of inhibition.

Turnout

2020 ◽  
pp. 409-426
Author(s):  
Pedro Riera
Keyword(s):  
Crucial Aspect ◽  
Individual Level ◽  
The Third ◽  
Explanatory Factors ◽  
Different Types ◽  
Sources Of Variation ◽  
High Turnout ◽  
Democratic System ◽  
The Individual ◽  
Established Democracies

Voters’ turnout is always a crucial aspect in our explanation of election outcomes. A high turnout is often said to give legitimacy to the democratic system. Moreover, turnout usually has distributive effects: parties’ vote shares depend on the levels of turnout registered in a given election. My chapter has the following four aims. First of all, it offers a broad picture of electoral participation in Spain by comparing its level with data in other established democracies. Second, I examine the evolution of turnout in Spain and include information on the different types of elections that take place in the country. The third part of the chapter is devoted to studying the determinants of turnout at the aggregate (electoral district) level. Finally, I analyse what sources of variation in turnout exist at the individual level by taking into account the effect of three main groups of explanatory factors: sociodemographic, attitudinal, and economic.

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