scholarly journals Effects of container size, density, and incubation period on ammonium excretion rate measurements of planktonic copepods: Validation with a highly sensitive analytical method

2019 ◽  
Vol 14 (2) ◽  
pp. 62-70 ◽  
Author(s):  
Ken-ichi Nakamura ◽  
Kazutaka Takahashi ◽  
Shinji Shimode ◽  
Yugo Shimizu ◽  
Ken Furuya
2021 ◽  
Author(s):  
Anri Hirai ◽  
Ryo Yamazaki ◽  
Atsushi Kobayashi ◽  
Takashi Kimura ◽  
Kei Nomiyama ◽  
...  

Abstract Monoamine neurotransmitters (MAs), including dopamine (DA) and serotonin (5-HT), regulate brain functions such as behavior, memory, and learning. Neonicotinoids are pesticides that are being used more frequently. Neonicotinoid exposure has been observed to produce neurological symptoms, such as altered spontaneous movements and anxiety-like behaviors, which are suspected to be caused by altered MA levels. However, current neurotoxicity tests are not sufficiently sensitive to make these determinations. In this study, we performed some behavior tests and developed a sensitive and accurate analytical method using liquid chromatography-mass spectrometry (LC-MS/MS) to clarify the effects of neonicotinoid administration on MAs in the brain.We orally administered the neonicotinoid imidacloprid (0, 10, and 50 mg/kg body weight) to C57BL/6NCrSlc mice. In behavior tests, the decrease of activity was observed. The LC-MS/MS quantification of MAs in various brain regions by tetrafluoroborate salt of 2,4-diphenyl-pyranylium (DPP) derivatization, which was newly developed in this study, showed a decrease in some MA levels in the olfactory bulb and the striatum.Thus, in this study, we developed a new method for the sensitive detection of MAs by LC/MS using DPP derivatization. In addition, we showed that this sensitive MA quantification is effective in clarifying the neurotoxicity caused by chemical substances.


The results of this analysis illustrate three points. First, that for predictions of AIDS cases four to five years into the future, the back projection method is largely insensitive to the assumption one makes for the incubation period distribution. The two extreme distributions considered represent the fast and slow extremes of incubation period distribution usually proposed; distributions that lie between these two give predictions within the range of predictions that the two generate. The estimated number of new HIV infections, however, is highly sensitive to the assumed incubation period distribution; prediction of AIDS cases in the long term will be similarly sensitive.


Biosensors ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 325
Author(s):  
Li Fu ◽  
Jiangwei Zhu ◽  
Hassan Karimi-Maleh

Uric acid is an important indicator of the insect infestation assessment in flour. In this work, we propose a method for uric acid detection based on voltammetry. This technique is particularly considered for the physicochemical properties of flour and contains a simple pretreatment process to rapidly achieve extraction and adsorption of uric acid in flour. To achieve specific recognition of uric acid, graphene and poly(3,4-ethylenedioxythiophene) (PEDOT) were used for the adsorption and concentration of uric acid in flour. The adsorbed mixture was immobilized on the surface of a screen-printed electrode for highly sensitive detection of the uric acid. The results showed that electrocatalytic oxidation of uric acid could be achieved after adsorption by graphene and PEDOT. This electrocatalytic reaction allows its oxidation peak to be distinguished from those of other substances that commonly possess electrochemical activity. This voltammetry-based detection method is a portable and disposable analytical method. Because it is simple to operate, requires no professional training, and is inexpensive, it is a field analysis method that can be promoted.


1997 ◽  
Vol 110 (3) ◽  
pp. 305-309 ◽  
Author(s):  
Tatsuhiko Kataoka ◽  
Maiko Mori ◽  
Tomoko M. Nakanishi ◽  
Satoshi Matsumoto ◽  
Akira Uchiumi

Lab on a Chip ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 2113-2121 ◽  
Author(s):  
Kenji Akama ◽  
Hiroyuki Noji

Homogeneous digital immunoassay is a powerful analytical method for highly sensitive biomarker detection with a simple protocol. By using this method, we demonstrated the simultaneous multiple protein detection.


Author(s):  
R. H. Kaspi ◽  
D. E. Luzzi

The HREM is highly sensitive to the presence of crystals in a specimen. As a results, researchers often report the presence of some fringe contrast in an otherwise amorphous image. The potential for obtaining more information than just a sense of the presence of crystal has not been addressed in detail. In the interest of allowing some amount of quantitative analysis of HREM images of partially and fully amorphous materials, we have developed an analytical method with which to quantify the directionality of an image using stereology.Figure 1 is a series of HREM images taken through the crystal - amorphous interface of an electron irradiated Cu-Ti intermetallic alloy. The first image is from an unirradiated crystalline region. The second image is from a low dose irradiated region, while the third is from a region that has been irradiated to a dose just under the necessary dosage for a total amorphous transition.


2019 ◽  
Vol 206 ◽  
pp. 504-510 ◽  
Author(s):  
Siying Zhang ◽  
Guanglian Zhou ◽  
Xiao Zhang ◽  
Dong Chen ◽  
Jian Liu ◽  
...  

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Jonathan Faro ◽  
Malika Mitchell ◽  
Yuh-Jue Chen ◽  
Sarah Kamal ◽  
Gerald Riddle ◽  
...  

Background. Elucidation of a pathogen’s antimicrobial susceptibility requires subculture after the organism is first isolated. This takes several days, requiring patients to be treated with broad-spectrum antibiotics. This approach contributes to the development of bacterial resistance.Methods. Microtiter wells were coated with a polyclonal antibody targeting the pathogen of interest. Bacterial suspensions were added in the presence/absence of selected antibiotics. After washing, captured bacteria were detected.Findings. Group B streptococcus (GBS),Enterococcus faecalis, andNeisseria gonorrhoeaewere each detected at 105 bacteria/mL following a 20-minute incubation period. Susceptibility to select antibiotics was discernable following a 6-hour incubation period (GBS andEnterococcus). Sensitivity was increased to 10−2 bacteria/mL for GBS, 10−1 bacteria/mL forE. faecalis, and 101 bacteria/mL forN. gonorrhoeaefollowing 18–24-hour culture.Conclusion. This novel assay allows for the highly sensitive and specific identification of a pathogen and simultaneous determination of its antimicrobial susceptibility in a reduced time.


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