A Rapid Procedure to Evaluate the Effect of Pesticides on Nitrification

A laboratory procedure for evaluating the effect of pesticides on nitrification in soil proved to be simple to perform, reproducible, and offers a procedure for rapid screening of a large number of chemicals in a short period. The recovery of added nitrate by extracting with distilled water was essentially 100% complete. The conversion of added ammonium to nitrate by the soil microorganisms was nearly complete after the 2-week incubation period. Nitrification in soil treated with several different herbicides and insecticides was determined by our procedure. A nitrification inhibitor, N-Serve3 (2-chloro-6-trichloromethyl pyridine) was included as a standard. None of the herbicides or insecticides inhibited nitrification and the N-Serve completely inhibited nitrification during the 2-week incubation.

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NITROGEN TRANSFORMATIONS NEAR UREA IN SOIL WITH DIFFERENT WATER POTENTIALS

Canadian Journal of Soil Science ◽

10.4141/cjss88-055 ◽

1988 ◽

Vol 68 (3) ◽

pp. 569-576 ◽

Cited By ~ 14

Author(s):

YADVINDER SINGH ◽

E. G. BEAUCHAMP

Keyword(s):

Water Potential ◽

Soil Water ◽

Incubation Period ◽

Relative Rate ◽

Soil Water Potential ◽

Nitrification Inhibitor ◽

Silt Loam ◽

Nitrogen Transformations ◽

Water Potentials ◽

Initial Soil

Two laboratory incubation experiments were conducted to determine the effect of initial soil water potential on the transformation of urea in large granules to nitrite and nitrate. In the first experiment two soils varying in initial soil water potentials (− 70 and − 140 kPa) were incubated with 2 g urea granules with and without a nitrification inhibitor (dicyandiamide) at 15 °C for 35 d. Only a trace of [Formula: see text] accumulated in a Brookston clay (pH 6.0) during the transformation of urea in 2 g granules. Accumulation of [Formula: see text] was also small (4–6 μg N g−1) in Conestogo silt loam (pH 7.6). Incorporation of dicyandiamide (DCD) into the urea granule at 50 g kg−1 urea significantly reduced the accumulation of [Formula: see text] in this soil. The relative rate of nitrification in the absence of DCD at −140 kPa water potential was 63.5% of that at −70 kPa (average of two soils). DCD reduced the nitrification of urea in 2 g granules by 85% during the 35-d period. In the second experiment a uniform layer of 2 g urea was placed in the center of 20-cm-long cores of Conestogo silt loam with three initial water potentials (−35, −60 and −120 kPa) and the soil was incubated at 15 °C for 45 d. The rate of urea hydrolysis was lowest at −120 kPa and greatest at −35 kPa. Soil pH in the vicinity of the urea layer increased from 7.6 to 9.1 and [Formula: see text] concentration was greater than 3000 μg g−1 soil. There were no significant differences in pH or [Formula: see text] concentration with the three soil water potential treatments at the 10th day of the incubation period. But, in the latter part of the incubation period, pH and [Formula: see text] concentration decreased with increasing soil water potential due to a higher rate of nitrification. Diffusion of various N species including [Formula: see text] was probably greater with the highest water potential treatment. Only small quantities of [Formula: see text] accumulated during nitrification of urea – N. Nitrification of urea increased with increasing water potential. After 35 d of incubation, 19.3, 15.4 and 8.9% of the applied urea had apparently nitrified at −35, −60 and −120 kPa, respectively. Nitrifier activity was completely inhibited in the 0- to 2-cm zone near the urea layer for 35 days. Nitrifier activity increased from an initial level of 8.5 to 73 μg [Formula: see text] in the 3- to 7-cm zone over the 35-d period. Nitrifier activity also increased with increasing soil water potential. Key words: Urea transformation, nitrification, water potential, large granules, nitrifier activity, [Formula: see text] production

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Discrete simulation analysis of COVID-19 and prediction of isolation bed numbers

PeerJ ◽

10.7717/peerj.11629 ◽

2021 ◽

Vol 9 ◽

pp. e11629

Author(s):

Xinyu Li ◽

Yufeng Cai ◽

Yinghe Ding ◽

Jia-Da Li ◽

Guoqing Huang ◽

...

Keyword(s):

Incubation Period ◽

Simulation Analysis ◽

Response Speed ◽

Healing Time ◽

World Health ◽

Population Mobility ◽

Medical Systems ◽

Discrete Simulation ◽

Period 2 ◽

Short Period

Background The outbreak of COVID-19 has been defined by the World Health Organization as a pandemic, and containment depends on traditional public health measures. However, the explosive growth of the number of infected cases in a short period of time has caused tremendous pressure on medical systems. Adequate isolation facilities are essential to control outbreaks, so this study aims to quickly estimate the demand and number of isolation beds. Methods We established a discrete simulation model for epidemiology. By adjusting or fitting necessary epidemic parameters, the effects of the following indicators on the development of the epidemic and the occupation of medical resources were explained: (1) incubation period, (2) response speed and detection capacity of the hospital, (3) disease healing time, and (4) population mobility. Finally, a method for predicting the number of isolation beds was summarized through multiple linear regression. This is a city level model that simulates the epidemic situation from the perspective of population mobility. Results Through simulation, we show that the incubation period, response speed and detection capacity of the hospital, disease healing time, degree of population mobility, and infectivity of cured patients have different effects on the infectivity, scale, and duration of the epidemic. Among them, (1) incubation period, (2) response speed and detection capacity of the hospital, (3) disease healing time, and (4) population mobility have a significant impact on the demand and number of isolation beds (P <0.05), which agrees with the following regression equation: N = P × (−0.273 + 0.009I + 0.234M + 0.012T1 + 0.015T2) × (1 + V).

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A Rapid Screening Test for the Diagnosis of Influenza Infection Incubation Period Using Coincidence Analysis of Pulse Waves

10.20944/preprints201710.0137.v1 ◽

2017 ◽

Author(s):

Po-Ying Chen ◽

Keng-Chang Tu ◽

Shyr-Shen Yu ◽

Wen-Kuan Yeh

Keyword(s):

Incubation Period ◽

Common Cold ◽

Pulse Wave ◽

Viral Infections ◽

Critical Role ◽

The Body ◽

Rapid Screening ◽

Screening Methods ◽

Viral Spread ◽

Pulse Waves

Viral infections have long been the biggest threat to human survival, and from a medical perspective, the development of noninvasive high-throughput screening methods that target the incubation period to either treat diseases or limit viral spread would be strikingly effective. Using this technology to target viral incubation periods would also be inexpensive to perform. The current study proposes to transform pulse signals into a rapid diagnostic test using “coincidence analysis” in the hope of preventing or reducing the symptoms of viral infections. The heart plays a critical role in calculating and supplying the needs of all tissues of the body. Pulse waves are pressurized signals in response to heart’s calculations and include all phases of the cardiac cycle, which maintains life and provides energy needed to perform tasks. Any small movement gives a corresponding signal to pulse waves. The current study investigated conclusive data on self-limiting infections, such as common cold. We used pulse wave, coincidence analysis technology to capture signals from individuals with common cold during the incubation period and investigated if particular characteristic signals could be applied to influenza during the incubation period. Preliminary work demonstrated that pulse waves could generate signals using this technology that would be worthwhile for future research. A small amount of analytical data from common cold existed previously. The data structure is based on the idea that a single pulse wave at differing physiological conditions would have slight modifications that would be amplified and presented by various geometrical shapes after extensive data are accumulated. These geometric shapes can then be sliced vertically or horizontally to extract data during different illness stages. The significance of these findings are impressive; from a personal or a public hygiene perspective, this analytical technology provides many benefits, such as rapid and precise decision-making that can be directly visualized or can be analyzed using software programs. Also, this technology also uses futuristic wearable technology that brings practical problem solving to physiology.

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Mysterious Outbreaks of Gastrointestinal Illness Associated with Burritos Supplied through School Lunch Programs†

Journal of Food Protection ◽

10.4315/0362-028x-69.7.1690 ◽

2006 ◽

Vol 69 (7) ◽

pp. 1690-1698 ◽

Cited By ~ 14

Author(s):

ELLEN B. STEINBERG ◽

ALDEN HENDERSON ◽

ADAM KARPATI ◽

MIKE HOEKSTRA ◽

NINA MARANO ◽

...

Keyword(s):

North Dakota ◽

Incubation Period ◽

Laboratory Data ◽

Clinical Syndrome ◽

Case Definition ◽

Etiologic Agent ◽

Gastrointestinal Illness ◽

Case Definitions ◽

The North ◽

Short Period

From October 1997 through March 1998, three outbreaks of gastrointestinal illness among school children were linked to company A burritos. In September 1998, a similar outbreak occurred in three North Dakota schools following lunches that included company B burritos. We conducted an investigation to determine the source of the North Dakota outbreak, identify other similar outbreaks, characterize the illness, and gather evidence about the cause. The investigation included epidemiologic analyses, environmental investigation, and laboratory analyses. In North Dakota, a case was defined as nausea, headache, abdominal cramps, vomiting, or diarrhea after lunch on 16 September 1998. Case definitions varied in the other states. In North Dakota, 504 students and staff met the case definition; predominant symptoms were nausea (72%), headache (68%), abdominal cramps (54%), vomiting (24%), and diarrhea (16%). The median incubation period was 35 min and median duration of illness was 6 h. Eating burritos was significantly associated with illness (odds ratio, 2.6; 95% confidence interval, 1.6 to 4.2). We identified 16 outbreaks that occurred in seven states from October 1997 through October 1998, affecting more than 1,900 people who ate burritos from two unrelated companies. All tortillas were made with wheat flour, but the fillings differed, suggesting that tortillas contained the etiologic agent. Results of plant inspections, tracebacks, and laboratory investigations were unrevealing. More than two million pounds of burritos were recalled or held from distribution. The short incubation period, symptoms, and laboratory data suggest that these outbreaks were caused by an undetected toxin or an agent not previously associated with this clinical syndrome. Mass psychogenic illness is an unlikely explanation because of the large number of sites where outbreaks occurred over a short period, the similarity of symptoms, the common food item, the lack of publicity, and the link to only two companies. A network of laboratories that can rapidly identify known and screen for unknown agents in food is a critical part of protecting the food supply against natural and intentional contamination.

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Mutagenic properties of modified hydrothermal nanotitania extract

Bangladesh Journal of Medical Science ◽

10.3329/bjms.v19i1.43890 ◽

2019 ◽

Vol 19 (1) ◽

pp. 159-162

Author(s):

Ahmad Mukifza Harun ◽

Noor Baizura Ab Ghani ◽

Nor Farid Mohd Noor ◽

Razif Abas ◽

Mohammad Khursheed Alam

Keyword(s):

Incubation Period ◽

Rat Liver ◽

Ames Test ◽

Medical Science ◽

Metabolic Activation ◽

Mutagenic Effect ◽

Distilled Water ◽

Standard Assay ◽

Serial Dilutions

Backgrounds: The mutagenic properties of modified hydrothermal nanotitania extract were carried out using the Ames test (genotoxicity). Materials and methods: The Ames test was performed on Salmonella strains (TA98, TA100, TA1535, TA1537 and TA 102) which contain mutations in several genes with and without S9 metabolic activation from rat liver using the standard assay. The materials were extracted in distilled water and the serial dilutions of concentration ranging from 313 to 5000 μg/mLwere used after the incubation period of 24 h at 37° C. Results: These results suggested that all tested concentrations of the material extracts did not produce mutagenic effect in all the strains tested. Conclusions: Findings from this study showed that the modified hydrothermal nanotitania extract was non-mutagenic under present conditions. Bangladesh Journal of Medical Science Vol.19(1) 2020 p.159-162

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THE LIVER AS A SOURCE OF BACTERIAL AGGLUTININ

Journal of Experimental Medicine ◽

10.1084/jem.41.6.767 ◽

1925 ◽

Vol 41 (6) ◽

pp. 767-778 ◽

Cited By ~ 6

Author(s):

F. S. Jones

Keyword(s):

Sulfuric Acid ◽

Blood Serum ◽

Single Injection ◽

Distilled Water ◽

Mesenteric Vein ◽

Hog Cholera ◽

Short Period ◽

Accurate Comparison ◽

Considerable Concentration

Serum and tissues containing agglutinin for the hog cholera bacillus may be dried in vacuo over sulfuric acid without appreciably injuring the antibody. The desiccated material when extracted with appropriate amounts of distilled water offers a basis for accurate comparison of antibody content. The greatest concentration of agglutinin occurred in the liver, provided the animals injected with small amounts of antigen were killed within a short period. The serum of those more highly immunized contained the greatest concentration of antibody. A single injection of antigen into a radicle of the mesenteric vein resulted in a considerable concentration of agglutinin in the liver. Other experiments indicated that the liver does not act as a reservoir for the antibody. It has also been shown that this concentration of agglutinin cannot be ascribed to the blood left within the liver, since the blood serum was relatively poor in antibody. The experiments indicate that the agglutinin was produced within the liver.

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Laboratory Procedure for Rapid Screening of Reverse Osmosis Membrane Anti-Scalants

Wuhan University Journal of Natural Sciences ◽

10.1007/s11859-019-1363-0 ◽

2019 ◽

Vol 24 (1) ◽

pp. 15-22

Author(s):

Jiaqiang Wei ◽

Baiqing Zhou ◽

Kai Liu ◽

Tao Wan ◽

Shangkun Gong ◽

...

Keyword(s):

Reverse Osmosis ◽

Rapid Screening ◽

Reverse Osmosis Membrane ◽

Laboratory Procedure

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Application of microfluidic high-throughput quantitative PCR systems for the monitoring and surveillance of aquatic species

ARPHA Conference Abstracts ◽

10.3897/aca.4.e65100 ◽

2021 ◽

Vol 4 ◽

Author(s):

Luca Mirimin ◽

Dennis van der Pouw Kraan

Keyword(s):

Quantitative Pcr ◽

High Throughput ◽

Environmental Samples ◽

Rapid Screening ◽

Sampling Effort ◽

Sample Processing ◽

Important Species ◽

Short Period ◽

Wide Range ◽

Species Specific

Quantitative PCR (qPCR) has been increasingly used for the detection of target organisms in environmental DNA (eDNA) studies, and this is thanks to high sensitivity and ability to quantify DNA targets copy number. However, prior to their implementation, qPCR species-specific assays must be developed and validated and, when implemented, they are limited to relatively low number of targets that can be screened as a multiplex or in parallel. Thanks to recent technological advances, several qPCR-based platforms have become available to increase the throughput capability of qPCR systems as well as lowering time of execution and costs associated to sample processing. The present study describes the use of a microfluidic high-throughput qPCR/dPCR system (Biomark HD, Fluidigm) for the screening of species of ecologic and economic importance in bulk plankton environmental samples from marine coastal areas around the Irish coast. Data was generated using the configuration enabling the highest throughput (in terms of data points) of the system, including Integrated Fluidic Control (IFC) units capable of producing 96 x 96 sample/assay combinations in each run (9,216 individual qPCR tests in a single run). Thanks to such a capability, it was possible to execute the following three main development and implementation phases in a relatively short period of time (weeks as opposed to months/years): (i) development of a panel of species-specific assays targeting a range of crustacean and bivalve species; (ii) assessment of Limits of Detection (LOD), Limits of Quantification (LOQ), and enzymatic inhibition control for selected assays; and (iii) screening of environmental time-series samples (n = 242) obtained from a citizen-like sampling effort that involved a range of stakeholders and locations throughout the Irish marine coastal territory between 2019 and 2020. During the assay-development phase, the IFC system configuration (whereby all assays are tested in parallel against all samples) enabled the rapid screening of species-specific assays against a wide range of (genomic DNA of) non-target organisms, hence enabling for rapid specificity testing. LOD/LOQ experiments showed high levels of sensitivity and thanks to the large number of assays that could be accommodated in a single run, it was possible to include up to four distinct Internal Positive Controls (IPCs) at different concentrations in each run (hence controlling for potential inhibition at different target concentration levels). The inclusion of inhibitor-removal reagents in a pre-amplification step as well as the dilution factor of conducting reactions in small volumes (6.7 nL reaction volumes, hence comparable to a “digital PCR” effect) proved to be an effective strategy to reduce the effect of inhibitors in control experiments (humic acid and EDTA), as well as in actual environmental samples from a range of marine environments. Combining such a high-throughput screening platform with a nation-wide citizen science-like sampling programme enabled the acquisition of large datasets that are being used to monitor occurrence and (spawning) activity of important species that are of conservation concern, commercial value, or non-indigenous and invasive to Irish waters. The Biomark HD system provides a remarkable flexibility to modify existing and/or incorporate new assays because IFCs are customizable just prior to usage (i.e. are not pre-loaded or spotted with primers/probes), thus current work is focussing on increasing the number of species targeted in a single run, and (thanks to the quantitative nature of data) discriminating between different fractions of DNA in heterogeneous bulk samples (e.g. gametes and larvae vs intra- and extracellular eDNA). Thanks to low sample processing cost, assay flexibility and high-throughput capability, microfluidic qPCR platforms behold the potential to significantly advance biomonitoring of aquatic ecosystems.

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Effect of Acipimox on Plasma Lipids and Glucose/Insulin in Pregnant Rats

International Journal of Experimental Diabetes Research ◽

10.1080/15604280214938 ◽

2002 ◽

Vol 3 (4) ◽

pp. 233-239 ◽

Cited By ~ 3

Author(s):

I. Sánchez-Vera ◽

B. Bonet ◽

M. Viana ◽

E. Herrera ◽

A. Indart

Keyword(s):

Plasma Glucose ◽

Plasma Lipids ◽

Late Pregnancy ◽

Oral Glucose ◽

Distilled Water ◽

Pregnant Rats ◽

Glucose Levels ◽

Peripheral Insulin Resistance ◽

Short Period ◽

Plasma Ffa

To determine how a reduction in maternal hypertriglyceridemia during late pregnancy may affect glucose/insulin relationships, pregnant and virgin rats were orally treated with acipimox, a potent antilipolytic agent. In 20-day pregnant rats receiving 80 mg of acipimox, plasma triglycerides (TG), free fatty acids (FFA), and glycerol decreased more than in virgin rats shortly after the drug (up to 7 hours), when compared with animals treated with distilled water, whereas plasma glucose level was unaffected by the treatment in either group of rats. When acipimox was given every 12 hours from day 17 to day 20 of pregnancy, plasma TG, FFA, and glycerol levels progressively increased, whereas they either decreased or did not change in virgin rats receiving the same treatment, with no effect in plasma glucose levels in either group. Fetal body weight was lower than in controls in 20-day pregnant rats that received acipimox for 3 days. On day 20 of pregnancy, 3 hours after receiving acipimox or distilled water, rats received a 2 g glucose/kg oral load and it was found that the change in plasma glucose was similar in both groups, whereas the increase in plasma insulin was greater in pregnant rats treated with acipimox. However, no difference was found in either variable after the oral glucose load in virgin rats receiving acipimox or distilled water. No differences in plasma glucose levels were found after intravenous (IV) administration of insulin in pregnant rats treated or not treated with acipimox. In conclusion, present results show that administration of acipimox during the last days of gestation inhibited lipolysis and decreased fetal weight. Over a short period of time, in pregnant rats, reductions of plasma FFA and TG after acipimox treatment improved the glucose-induced insulin release, but did not seem to have any effect in peripheral insulin resistance.

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