scholarly journals Design and evaluation of a 10-ma dc current reference standard

2003 ◽  
Vol 52 (2) ◽  
pp. 440-444 ◽  
Author(s):  
G. Fernqvist ◽  
G. Hudson ◽  
J. Pickering ◽  
F. Power
Keyword(s):  
Reference Standard ◽  
Current Reference ◽  
Dc Current ◽  
Current Reference Standard

scholarly journals Droplet Digital PCR – A Superior Complementary Technique for SARS-CoV-2 Detection

2020 ◽  
pp. 12-15
Author(s):  
I. M. Hussaini ◽  
S. Gide ◽  
B. Musa ◽  
M. A. Sulaiman ◽  
A. Usman
Keyword(s):  
Sensitivity And Specificity ◽  
False Negative ◽  
Standard Technique ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Reference Standard ◽  
Rt Pcr ◽  
Negative Results ◽  
False Negative Results ◽  
Current Reference Standard

Accurate and timely SARS-CoV-2 detection in suspected persons is crucial in the fight against its spread. Many techniques have been developed to meet up with the continuously growing demand, however some of these techniques lack the required accuracy, sensitivity and specificity. The current reference standard technique for SARS-CoV-2 detection is RT-PCR, but studies have shown that false-negative results are inevitable and data can be non-reproducible when samples and primers are not appropriately verified and validated. Droplet digital PCR (ddPCR) is a newly introduced technique that performs precise nucleic acid quantification. Researchers have evaluated the efficacy of ddPCR and the technique has shown promising results even in specimens with low viral load. ddPCR has shown increased accuracy, precision, sensitivity and specificity. Furthermore, it is less affected by annealing and amplification inhibitors. This suggests that ddPCR can be used as a complementary detection technique especially in convalescent cases.

scholarly journals PSG-Audio, a scored polysomnography dataset with simultaneous audio recordings for sleep apnea studies

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Georgia Korompili ◽  
Anastasia Amfilochiou ◽  
Lampros Kokkalas ◽  
Stelios A. Mitilineos ◽  
Nicolas- Alexander Tatlas ◽  
...  
Keyword(s):  
Sleep Apnea ◽  
Sleep Apnea Syndrome ◽  
Reference Standard ◽  
Detection Techniques ◽  
Detection Systems ◽  
Home Based ◽  
Audio Recordings ◽  
Apnea Detection ◽  
Current Reference Standard

AbstractThe sleep apnea syndrome is a chronic condition that affects the quality of life and increases the risk of severe health conditions such as cardiovascular diseases. However, the prevalence of the syndrome in the general population is considered to be heavily underestimated due to the restricted number of people seeking diagnosis, with the leading cause for this being the inconvenience of the current reference standard for apnea diagnosis: Polysomnography. To enhance patients’ awareness of the syndrome, a great endeavour is conducted in the literature. Various home-based apnea detection systems are being developed, profiting from information in a restricted set of polysomnography signals. In particular, breathing sound has been proven highly effective in detecting apneic events during sleep. The development of accurate systems requires multitudinous datasets of audio recordings and polysomnograms. In this work, we provide the first open access dataset, comprising 212 polysomnograms along with synchronized high-quality tracheal and ambient microphone recordings. We envision this dataset to be widely used for the development of home-based apnea detection techniques and frameworks.

ANTI-OVULATORY ACTIVITY OF STEROIDS ADMINISTERED BY GAVAGE IN THE ADULT OESTRUS RABBIT

1963 ◽  
Vol 42 (2_Suppl) ◽  
pp. S17-S30
Author(s):  
Fred A. Kind ◽  
Ralph I. Dorfman
Keyword(s):  
Dose Response ◽  
Active Compound ◽  
Subcutaneous Injection ◽  
Response Curve ◽  
Parent Compound ◽  
Dose Response Curve ◽  
Relative Potency ◽  
Reference Standard ◽  
Highly Active ◽  
Dose Levels

ABSTRACT Thirty-seven steroids have been studied as orally effective inhibitors of ovulation in the mated oestrus rabbit. Norethisterone served as the reference standard and a dose response curve was established between the 0.31 and 1.25 mg dose levels. Nine highly active anti-ovulatory compounds are described listed in a decreasing order of potency with norethisterone having the arbitrary value of one: 6-chloro-Δ6-dehydro-17α-acetoxyprogesterone (35), 6α-methyl-Δ1-dehydro-17α-acetoxyprogesterone (≥ 10), 6-fluoro-Δ6-dehydro-17α-acetoxyprogesterone(9), 6-methyl-Δ6-dehydro-17α-acetoxyprogesterone (5), Δ6-dehydro-17α-acetoxyprogesterone (≥ 3), 6α-methyl-17α-acetoxyprogesterone (2.6), 6-chloro-Δ1,6-bisdehydro-17α-acetoxyprogesterone (≥ 2), 2-hydroxymethyl-17α-methyl-17β-hydroxyandrostan-3-one (≥ 2), and 6α-fluoro-16α-methyl-17α-acetoxyprogesterone (≥ 1.25). The anti-ovulatory activity of a compound was not related necessarily to the progestational activity of a compound nor to the anti-gonadotrophic activity as measured in parabiotic rats. 6-Chloro-Δ60dehydro-17-acetoxyprogesterone was as effective by gavage as previously shown by subcutaneous injection. 2-Hydroxymethyl-17α-methyl-17β-hydroxyandrostan-3-one was at least 2.5 times more active by gavage than by injection. While 17α-acetoxyprogesterone was a very weak anti-ovulatory steroid, modifications of the structure by addition of methyl or halogen at the 6α position with or without unsaturation greatly increased the activity. 6-Chloro-Δ6-dehydro-27α-acetoxyprogesterone was the most active compound in this series showing a relative potency of 3500 times that of the parent compound 17α-acetoxyprogesterone.

BIOASSAY CHARACTERISTICS OF INDIVIDUAL URINARY GONADOTROPHIN EXTRACTS

1963 ◽  
Vol 42 (2) ◽  
pp. 214-224
Author(s):  
Raymond C. Mellinger ◽  
Jalileh A. Mansour ◽  
Richmond W. Smith
Keyword(s):  
Reference Material ◽  
Young Women ◽  
Reference Standard ◽  
General Acceptance ◽  
Modifying Factors ◽  
Large Numbers ◽  
The World ◽  
Quantitative Bioassay ◽  
Different Parts ◽  
Age And Sex

ABSTRACT A reference standard is widely sought for use in the quantitative bioassay of pituitary gonadotrophin recovered from urine. The biologic similarity of pooled urinary extracts obtained from large numbers of subjects, utilizing groups of different age and sex, preparing and assaying the materials by varying techniques in different parts of the world, has lead to a general acceptance of such preparations as international gonadotrophin reference standards. In the present study, however, the extract of pooled urine from a small number of young women is shown to produce a significantly different bioassay response from that of the reference materials. Gonadotrophins of individual subjects likewise varied from the multiple subject standards in many instances. The cause of these differences is thought to be due to the modifying influence of non-hormonal substances extracted from urine with the gonadotrophin and not necessarily to variations in the gonadotrophins themselves. Such modifying factors might have similar effects in a comparative assay of pooled extracts contributed by many subjects, but produce significant variations when material from individual subjects is compared. It is concluded that the expression of potency of a gonadotrophic extract in terms of pooled reference material to which it is not essentially similar may diminish rather than enhance the validity of the assay.

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