A problem of Rosser and Turquette

1958 ◽  
Vol 23 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Angelo Margaris
Keyword(s):  
Positive Result ◽  
Negative Results ◽  
A Value ◽  
Truth Value ◽  
Affirmative Solution ◽  
Present Section

In this paper an affirmative solution is given for the following problem in many-valued logic posed by Rosser and Turquette in [6] p. 110:For every triple ‹s, t, m› with 1 ≤ s < t < m, is it possible to define a system of m-valued logic which satisfies the following conditions? I. Every statement which always takes values ≦ s is provable. II. No statement which ever takes a value > t is provable. III. Of those statements which always take values ≤ t and sometimes take a value > s, some are provable and some are not.We state now, temporarily deferring comment, a more demanding alternative to Condition III: III′. For every truth value k such that s < k ≦ t, there are statements P and Q such that each takes the value k at least once, but never takes a value > k, and P is provable and Q is not.In § 2 a solution is given on the level of the statement calculus. The remainder of the present section is devoted to some negative results which serve to clarify the problem, and one positive result which shall cause us to replace Condition III by III′. We confine our attention to the statement calculus.

A Nylon Filter A-ELISA for Detecting Viruses in Water

1993 ◽  
Vol 27 (7-8) ◽  
pp. 135-141 ◽  
Author(s):  
Abidelfatah M. Nasser ◽  
Yehudit Elkana ◽  
Leon Goldstein
Keyword(s):  
Positive Result ◽  
Solid Phase ◽  
Enteric Viruses ◽  
High Specificity ◽  
Negative Results ◽  
Order Of Magnitude ◽  
Lower Background

This study was designed to develop a modification of A-ELISA performed in microtitre plates. Nylon filters have been utilized successfully as a solid phase for the performance of A-ELISA. The use of nylon filters resulted in lower background than nitro-cellulose and paper filters, indicating their suitability as a solid phase for developing A-ELISA. With enteric viruses, human rotaviruses and MS-2 coliphage, negative results were obtained, suggesting high specificity of the developed technique for poliovirus 1. The sensitivity of the developed A-ELISA has been shown to be at least one order of magnitude greater than ordinary ELISA. A positive result with the nylon A-ELISA can be obtained with samples containing 100-1000 pfu/ml of poliovirus. Up to date methods used for detecting viruses in water are elaborate, time consuming and costly. Applying the nylon A-ELISA may overcome some of these disadvantages.

scholarly journals High-throughput quantitation of SARS-CoV-2 antibodies in a single-dilution homogeneous assay

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Markus H. Kainulainen ◽  
Eric Bergeron ◽  
Payel Chatterjee ◽  
Asheley P. Chapman ◽  
Joo Lee ◽  
...  
Keyword(s):  
Enzyme Linked Immunosorbent Assay ◽  
Specific Antibodies ◽  
Negative Results ◽  
A Value ◽  
Elisa Testing ◽  
The World ◽  
Antibody Titers ◽  
Qualitative Assay ◽  
Homogeneous Assay ◽  
Asymptomatic Infections

AbstractSARS-CoV-2 emerged in late 2019 and has since spread around the world, causing a pandemic of the respiratory disease COVID-19. Detecting antibodies against the virus is an essential tool for tracking infections and developing vaccines. Such tests, primarily utilizing the enzyme-linked immunosorbent assay (ELISA) principle, can be either qualitative (reporting positive/negative results) or quantitative (reporting a value representing the quantity of specific antibodies). Quantitation is vital for determining stability or decline of antibody titers in convalescence, efficacy of different vaccination regimens, and detection of asymptomatic infections. Quantitation typically requires two-step ELISA testing, in which samples are first screened in a qualitative assay and positive samples are subsequently analyzed as a dilution series. To overcome the throughput limitations of this approach, we developed a simpler and faster system that is highly automatable and achieves quantitation in a single-dilution screening format with sensitivity and specificity comparable to those of ELISA.

scholarly journals Experiments to test the possibility of transmutation by electronic bombardment

1927 ◽  
Vol 114 (767) ◽  
pp. 289-292 ◽  
Keyword(s):  
Melting Point ◽  
Positive Result ◽  
Quartz Tube ◽  
Pure Preparation ◽  
Negative Results

In an earlier paper experiments were described which were carried out in order to test the production of gold from mercury, as reported by Miethe and Stammreich, and by Nagaoka. These experiments led to conclusively negative results, but it was considered desirable to repeat also the work of Smits and Karssen upon the conversion of lead into thallium and mercury. To this end it was decided to adapt the quartz tube apparatus with sealed in tungsten leads, already used in the case of mercury, and described and illustrated in the previous paper (interrupted arc method). While waiting for a specially pure preparation of lead, tin suggested itself as a suitable metal for further experimentation. Besides its low melting point, there is the further advantage that indium, the most probable product of any transmutation of tin, can be spectroscopically detected in exceedingly minute traces, whilst its occurrence is so limited that the danger of accidental contamination from the ordinary materials of the laboratory is much smaller than is the case with most elements. In this respect, a positive result with indium would be more convincing than the production of mercury reported by Smits.

Determination of cannabinoids in oral fluid and urine of “light cannabis” consumers: a pilot study

2018 ◽  
Vol 57 (2) ◽  
pp. 238-243 ◽  
Author(s):  
Roberta Pacifici ◽  
Simona Pichini ◽  
Manuela Pellegrini ◽  
Roberta Tittarelli ◽  
Flaminia Pantano ◽  
...  
Keyword(s):  
Pilot Study ◽  
Oral Fluid ◽  
Urine Samples ◽  
Screening Tests ◽  
Gas Chromatography Mass Spectrometry ◽  
Negative Results ◽  
A Value ◽  
Order Of Magnitude ◽  
Confirmation Analysis

Abstract Background In those countries where cannabis use is still illegal, some manufacturers started producing and selling “light cannabis”: dried flowering tops containing the psychoactive principle Δ-9-tetrahydrocannabinol (THC) at concentrations lower than 0.2% together with variable concentration of cannabidiol (CBD). We here report a pilot study on the determination of cannabinoids in the oral fluid and urine of six individuals after smoking 1 g of “light cannabis”. Methods On site screening for oral fluid samples was performed, as a laboratory immunoassay test for urine samples. A validated gas chromatography-mass spectrometry (GC-MS) method was then applied to quantify THC and CBD, independently from results of screening tests. Results On site screening for oral fluid samples, with a THC cut-off of 25 ng/mL gave negative results for all the individuals at different times after smoking. Similarly, negative results for urine samples screening from all the individuals were obtained. Confirmation analyses showed that oral fluid THC was in the concentration range from 2.5 to 21.5 ng/mL in the first 30 min after smoking and then values slowly decreased. CBD values were usually one order of magnitude higher than those of THC. THC-COOH, the principal urinary THC metabolite, presented the maximum urinary value of 1.8 ng/mL, while urinary CBD had a value of 15.1 ng/mL. Conclusions Consumers of a single 1 g dose of “light cannabis” did not result as positive in urine screening, assessing recent consumption, so that confirmation would not be required. Conversely, they might result as positive to oral fluid testing with some on-site kits, with THC cut-off lower than 25 ng/mL, at least in the first hour after smoking and hence confirmation analysis can be then required. No conclusions can be drawn of eventual chronic users.

scholarly journals False Negative Results in High Viremia Parvovirus B19-Samples Tested with Real-Time PCR

2010 ◽  
Vol 59 (2) ◽  
pp. 129-132 ◽  
Author(s):  
PIOTR GRABARCZYK ◽  
ALEKSANDRA KALIŃSKA ◽  
EWA SULKOWSKA ◽  
EWA BROJER
Keyword(s):  
Positive Result ◽  
Real Time ◽  
Real Time Pcr ◽  
Parvovirus B19 ◽  
False Negative ◽  
Immunocompromised Patients ◽  
Negative Results ◽  
False Negative Results ◽  
Parvovirus B 19 ◽  
The Way

Extremely high viremia is observed during some viruses infection, especialy in immunocompromised patients. False negative results of Parvovirus B 19 DNA tests performed with real-time PCR in high viremic samples are reported. The way of fluorescence diagrams analysis and algorithm of positive result confirmation to exclude such phenomenon are proposed.

An evaluation of four serum tests for pregnancy.

1983 ◽  
Vol 29 (3) ◽  
pp. 561-563 ◽  
Author(s):  
K W Ryder ◽  
R A Munsick ◽  
T O Oei ◽  
P C Young ◽  
H F Blackford
Keyword(s):  
Positive Result ◽  
Early Pregnancy ◽  
Beta Subunit ◽  
The Other ◽  
Analytical Sensitivity ◽  
Negative Results ◽  
Human Choriogonadotropin ◽  
Beta Hcg

Abstract We evaluated four pregnancy tests (Biocept-G, Beta-CG, Preg/Stat, and HCG-Beta Screen), using sera from 59 nonpregnant subjects and 77 patients with serum human choriogonadotropin beta-subunit (beta-hCG) concentrations ranging from 4 to 100 000 int. units/L. The results obtained for each test were compared with the results predicted on the basis of the sample's beta-hCG concentration and the beta-hCG concentration the manufacturer claimed necessary for a positive result (the test's analytical sensitivity). Biocept-G had the best sensitivity (100%), specificity (98.9%), and accuracy (99.2%). Beta-CG had the poorest sensitivity (86.4%), Preg/Stat the poorest specificity (87.5%), and accuracy (92.6%). We confirmed the manufacturer's claimed analytical sensitivity (200 int. units/L) for the Biocept-G procedure, but our calculated analytical sensitivity for the other tests was significantly different from that claimed by their manufacturers. Best results were obtained with Biocept-G, but with its analytical sensitivity of 200 int. units/L, samples from early pregnancy will give negative results. None of the pregnancy tests evaluated here will establish the presence or absence of early pregnancy with certainty.

scholarly journals Risk for intravesical recurrence of bladder cancer stratified by the results on two consecutive UroVysion fluorescence in situ hybridization tests: a prospective follow-up study in Japan

2020 ◽  
Vol 25 (6) ◽  
pp. 1163-1169
Author(s):  
Atsushi Ikeda ◽  
Takahiro Kojima ◽  
Koji Kawai ◽  
Shiro Hinotsu ◽  
Naoto Keino ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Positive Result ◽  
Recurrence Rates ◽  
Follow Up Study ◽  
Negative Results ◽  
Negative Findings ◽  
History Of ◽  
Muscle Invasive ◽  
Positive Results

Abstract Background A previous comparative study in Japan has demonstrated that the two consecutive UroVysion tests are useful tools to detect the presence of bladder cancer during follow-up after transurethral resection, but they also presented their high rates of false-positive results. Here, we aimed to evaluate the relationship between the UroVysion tests and subsequent intravesical recurrence. Methods In the previous study, patients without bladder cancer during the first analysis showed the same examination set repeated 3 months later as the second analysis. In this follow-up study, 326 patients showed negative findings confirmed on cystoscopy during the second UroVysion test. Recurrence-free survival was assessed using a median follow-up of 27 months. Results In the two consecutive UroVysion tests, 214 patients (65.6%) showed negative UroVysion results in both tests, whereas 91 presented a positive result on either tests and 21 patients presented positive results in both tests. During the follow-up, 40 patients (12.3%) had an intravesical recurrence with non-muscle-invasive bladder cancer. The recurrence rates in patients with negative results in both tests, those with one positive result in either tests, and those with positive results in both tests were 8.4%, 16.5%, and 33.3%, respectively. The multivariate analysis indicated that the history of bladder cancer and the consecutive UroVysion test pattern were independent risk factors for recurrence. Conclusions Our data confirmed the effectiveness of two consecutive UroVysion tests in predicting intravesical recurrence after TURBT. Further prospective studies would help determine an appropriate interval for cystoscopy follow-up.

Evaluating the Effectiveness of Somatostatin Receptors Scintigraphy with 111In-Octreotide in the Diagnosis of Neuroendocrine Tumors

2018 ◽  
pp. 44-51
Author(s):  
А. Маркович ◽  
A. Markovich ◽  
С. Ширяев ◽  
S. Shiryaev ◽  
М. Гончаров ◽  
...  
Keyword(s):  
Positive Result ◽  
Neuroendocrine Tumors ◽  
Predictive Value ◽  
Single Photon ◽  
Somatostatin Receptors ◽  
Photon Emission ◽  
Neuroendocrine Neoplasm ◽  
Characteristic Parameters ◽  
Single Photon Emission ◽  
Negative Results

Purpose: Exploring methods to improve diagnosis of neuroendocrine tumors (NET) in different locations using somatostatin receptors scintigraphy with 111In-octreotide. Material and methods: The study included 125 patients with NET in different locations. Activity of injected 111In-octreotide was 200–250 MBq (effective dose – 0.054 mSv/MBq), which allows to carry out a planar study as and single photon emission computed tomography. The study was performed after 24 hours on intravenous injection of indicator on the combined SPECT/CT machine Symbia T2 (Siemens, Germany). Results: In the sample of patients, NET distribution by localization is indicated in Fig. 1. The results of the study with 111In-octreotide are presented in the form of scintigrams in the whole body scanning mode and in the form of single-photon emission computer tomograms combined with CT. To determine the effectiveness of scintigraphy with 111In-octreotide, after a visual evaluation of the scintigrams obtained, the number of positive and negative results of the study was calculated. A comparison was made with the data of other methods and the number of TP, TN, FP, and FN results was determined. Further, the characteristic parameters of the method studied were calculated to determine its effectiveness. The study of values of characteristic parameters showed that the sensitivity was 73 % (95 % CI: 63–83 %), specificity – 97 % (95 % CI: 88–100 %) accuracy is 79 % (95 % CI: 71–87 %). The value of the positive predictive value of 99 % (95 % CI: 94–100 %), the predictive value of negative results – 55 % (95 % CI: 40–70 %). While the study shows a high frequency of TP results, while the frequencies of the TN and FN results are not significantly different (the average frequency of the FN results falls within the confidence interval for the frequency of the TN results). The method has a high value of the prognostic value of the positive result, which gives the right to assert about the high probability of the presence of a neuroendocrine neoplasm in obtaining a positive result. In the present study, no FP results were obtained due to the presence of concomitant diseases, in which accumulation of used radiopharmaceutical is possible, since the data on the presence of such diseases were taken into account in the analysis of scintigrams. The data obtained in this paper are in good agreement with the data obtained by other authors, as well as early Russian publications. It is worth noting that the data of domestic authors were obtained on a small sample, without specifying confidence intervals; the injected activity was less than in this study. In addition, the possibility of obtaining more information than using classical imaging methods (for SPECT/CT, the tissue with the pathological accumulation of 111In-octreotide appeared to be intact on CT), allows us to recommend the method as a method of choice in the diagnosis of NET of different localization. Conclusions: The method of somatostatin receptors scintigraphy using domestic analogue of somatostatin in the diagnosis of NET has a high efficiency (efficiency of the method, calculated as the average value of the parameters of sensitivity and specificity of 85 % (95 % CI: 66–100 %).

Efficacy of treatment of vulva cancer patients and analysis of their hormonal status.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e21127-e21127
Author(s):  
Galina A. Nerodo ◽  
Ekaterina Nerodo
Keyword(s):  
Positive Result ◽  
Cancer Patients ◽  
Treatment Efficacy ◽  
Blood Concentration ◽  
Hormonal Status ◽  
Blood Concentrations ◽  
Negative Results ◽  
Group 2 ◽  
Vulva Cancer ◽  
Group 1

e21127 Background: hormonodependency of vulva is wellknown. This broughtusto study hormonal status of vulva cancer patients depending on treatment efficacy Methods: we present comparative analysis of hormonal status of vulva cancer patients in two groups: group 1 (50 patients) without relapse of the disease in 5-year period, and group 2 (35 patients) with relapse developed within the first year. Blood concentrations of testosterone, progesterone, follicle-stimulating hormone (FSH), luteinizing hormone were determined in all patients under study by means of radiometric methods. Estrone, estradiol, estriol with subsequent calculation of their sum were determined in daily urine by Brown method. Results: In the presence of effect (group 1) initial total amount of estrogens was twice as large than in its absence. In group 1 estradiol concentration exceeded the corresponding parameter of group 2 by three times(7.6±0.6 & 1,4±0.3,p<0.001). The amount of secreting estriol at positive result was almost twice higher than in cases of absence of the effect(10.02±1.7 & 4.6±0.49, p<0.001). The groups differed by secretion levels of follicle-stimulating and luteinizing hormones. Blood concentration of these hormones was lower in negative results that in positive. Distinct differences were also observed in progesterone and prolactin levels. In the group with positive result of treatment progesterone concentration was much higher than in the group without treatment effect. On the contrary, prolactin concentration in group 1 was significantly less than in group 2. The highest degree of reliability of quantitative indices related to treatment efficacy was observed for progesterone. Positive result of corresponding treatment may be predicted at normal initial progesterone level, and negative result at its low level (3-4 times lower than the norm). Another parameter - blood concentration of prolactin - can be used almost with the same degree of reliability. Conclusions: results of the study allow to suggest an existence of interrelation between treatment efficacy of vulva cancer patients and functional activity of hypophysis-gonadal system. Some of its parameters may be used to predict results of complex treatment of vulva cancer patients.

scholarly journals The Ticks of Rodents and their Nests, and the Discovery that Rhipicephalus sanguineus Latr. is the Vector of Tropical Typhus in Kenya

1935 ◽  
Vol 35 (1) ◽  
pp. 1-22 ◽  
Author(s):  
J. Isgaer Roberts
Keyword(s):  
Guinea Pig ◽  
Positive Result ◽  
Guinea Pigs ◽  
Rhipicephalus Sanguineus ◽  
Weather Conditions ◽  
Human Beings ◽  
Negative Results ◽  
Unfavourable Weather ◽  
The Subject ◽  
Made In

1. Earlier attempts to trace the vector of tropical typhus in Kenya failed. The only references to the subject in the available literature consist of mere suggestions that a mite would most likely prove to be the transmitter.2. An investigation made in an area whence most Nairobi cases of tropical typhus were reported, suggested that a tick (R. pulchellus) would be the most likely vector.3. Transmission experiments made in the belief that one of the unclassed fevers of man was conveyed by R. pulchellus have so far yielded negative results. There is, however, sufficient circumstantial evidence available pointing to this tick as vector of a form of mild typhus to man—this demands further investigation.4. At Mombasa and Nairobi, houses reported to be heavily infested with ticks, or houses investigated after the occurrence of the tropical typhus in them, have yielded only R. sanguineus.5. R. sanguineus (3 ♀), taken from a dog in a house where the last typhus case had occurred 8 months previously, gave a typical typhus syndrome when emulsified and inoculated into a male guinea-pig. R. sanguineus (1 ♀, 12 ⊙), taken in a house where a child had recently contracted typhus, also gave a positive result with guinea-pigs and the virus was further transmitted by passage through other guinea-pigs.6. The infestation of houses by R. sanguineus and the incidence of tropical typhus among human beings appear to be influenced by unfavourable weather conditions, causing the ticks to seek relatively dry and warm places for purposes of oviposition or metamorphosis, thus invading houses. In the absence of dogs, its usual hosts, the tick attacks man.

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