scholarly journals Unfair Noisy Channels and Oblivious Transfer

2003 ◽  
Vol 10 (36) ◽  
Author(s):  
Ivan B. Damgård ◽  
Serge Fehr ◽  
Kirill Morozov ◽  
Louis Salvail
Keyword(s):  
Positive Result ◽  
Oblivious Transfer ◽  
Gamma Delta ◽  
Noisy Channels ◽  
Bit Commitment ◽  
Correct Proof ◽  
Negative Results ◽  
Proof Sketch ◽  
A New Technique ◽  
Positive Results

In a paper from EuroCrypt'99, Damgård, Kilian and Salvail show various positive and negative results on constructing Bit Commitment (BC) and Oblivious Transfer (OT) from Unfair Noisy Channels (UNC), i.e., binary symmetric channels where the error rate is only known to be in a certain interval [gamma ..delta] and can be chosen adversarily. They also introduce a related primitive called PassiveUNC. We prove in this paper that any OT protocol that can be constructed based on a PassiveUNC and is secure against a passive adversary can be transformed using a generic "compiler'' into an OT protocol based on a UNC which is secure against an active adversary. Apart from making positive results easier to prove in general, this also allows correcting a problem in the EuroCrypt'99 paper: There, a positive result was claimed on constructing from UNC an OT that is secure against active cheating. We point out that the proof sketch given for this was incomplete, and we show that a correct proof of a much stronger result follows from our general compilation result and a new technique for transforming between weaker versions of OT with different parameters.

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.

scholarly journals On the (Im)possibility of Basing Oblivious Transfer and Bit Commitment on Weakened Security Assumptions

1998 ◽  
Vol 5 (37) ◽  
Author(s):  
Ivan B. Damgård ◽  
Joe Kilian ◽  
Louis Salvail
Keyword(s):  
Realistic Model ◽  
Oblivious Transfer ◽  
Partial Result ◽  
Noisy Channels ◽  
Information Theoretic ◽  
Bit Commitment ◽  
Information Theoretic Security ◽  
Threshold Phenomenon ◽  
Special Cases ◽  
Similar Threshold

We consider the problem of basing Oblivious Transfer (OT)<br />and Bit Commitment (BC), with information theoretic security, on seemingly weaker primitives.We introduce a general model for describing such primitives, called Weak Generic Transfer (WGT). This model includes as important special cases Weak Oblivious Transfer (WOT), where both<br />the sender and receiver may learn too much about the other party's input, and a new, more realistic model of noisy channels, called unfair noisy channels. An unfair noisy channel has a known range of possible noise levels; protocols must work for any level within this range against adversaries who know the actual noise level. We give a precise characterization for when one can base OT on WOT. When the deviation of the WOT from the ideal is above a certain threshold, we show that no information-theoretic reductions from OT (even against passive adversaries) and BC exist; when the deviation is below this threshold, we give a reduction from OT (and hence BC) that is information-theoretically secure against active adversaries.<br />For unfair noisy channels we show a similar threshold phenomenon for bit commitment. If the upper bound on the noise is above a threshold (given as function of the lower bound) then no information-theoretic reduction from OT (even against passive adversaries) or BC exist; when it is below this threshold we give a reduction from BC. As a partial result, we give<br />a reduction from OT to UNC for smaller noise intervals.

scholarly journals Clinical usefulness of cancer antigen 125 biomarker for tuberculosis diagnosis: experience in Cali, Colombia

2021 ◽  
Vol 70 (3) ◽  
pp. e92921
Author(s):  
Carl Sebastian Leib ◽  
Luis Gabriel Parra-Lara ◽  
Robinson Pacheco ◽  
Jose Fernando García-Goez
Keyword(s):  
Positive Result ◽  
University Hospital ◽  
Ca 125 ◽  
Bivariate Analysis ◽  
Cancer Antigen 125 ◽  
Cancer Antigen ◽  
Negative Results ◽  
Tb Treatment ◽  
Significant Difference ◽  
Positive Results

Introduction: Diagnosing extra-pulmonary tuberculosis (EPTB) is a challenge for physicians. It has been suggested that cancer antigen 125 (CA-125), which is produced by mesothelial cells, may be an EPTB diagnostic biomarker. Objective: To describe serum CA-125 levels behavior in patients with TB treated in a referral university hospital located in Cali, Colombia. Materials and methods: A cross-sectional study was conducted in 99 TB patients with CA-125 measurements (U/mL) made before TB treatment was started, and treated at Fundación Valle del Lili between 2007 and 2016. Cases were classified as pulmonary TB (PTB) (n=33) or EPTB (n=66). A bivariate analysis was performed to compare the variables of interest (sociodemographic, clinical, and laboratory findings data) between EPTB and PTB groups, and to determine differences between patients with CA-125 positive results and those with negative results in relation to mortality. Results: Elevated CA-125 levels were reported in 55 patients (55.56%). Positive CA-125 results (>35 U/mL) were more frequent in the EPTB group (59.09% vs. 48.48%). In the EPTB group, positive results were found in tuberculous serositis cases (100% pericardial TB, 68.42% peritoneal TB and 66.66% pleural TB), and in 66.66% of miliary TB and TB of the spine cases, respectively. Also, 15 TB infection-related deaths were reported in the follow-up period (n=66), of which 13 had a CA-125 positive result, finding a significant difference with those with negative results (p=0.021), however 47.05% of the surviving patients also had a positive result. Conclusions: Most of tuberculous serositis, miliary and TB of the spine cases showed elevated CA-125 levels before starting TB treatment. CA-125 may prove to be useful for prognostic purposes in these patients.

Critical Evaluation of Impedance Phlebography for the Diagnosis of Deep Vein Thrombosis

1974 ◽  
Vol 31 (02) ◽  
pp. 273-278
Author(s):  
Kenneth K Wu ◽  
John C Hoak ◽  
Robert W Barnes ◽  
Stuart L Frankel
Keyword(s):  
Deep Vein Thrombosis ◽  
False Positive ◽  
False Negative ◽  
Critical Evaluation ◽  
Original Method ◽  
Vein Thrombosis ◽  
Negative Results ◽  
False Negative Results ◽  
Deep Vein ◽  
Positive Results

SummaryIn order to evaluate its daily variability and reliability, impedance phlebography was performed daily or on alternate days on 61 patients with deep vein thrombosis, of whom 47 also had 125I-fibrinogen uptake tests and 22 had radiographic venography. The results showed that impedance phlebography was highly variable and poorly reliable. False positive results were noted in 8 limbs (18%) and false negative results in 3 limbs (7%). Despite its being simple, rapid and noninvasive, its clinical usefulness is doubtful when performed according to the original method.

PET/CT WITH 68GA-PSMA-11 IN DETECTION OF PRIMARY TUMOR AND RECURRENCE OF PROSTATE CANCER

2018 ◽  
Vol 64 (6) ◽  
pp. 799-804
Author(s):  
Darya Ryzhkova ◽  
M. Poyda
Keyword(s):  
Prostate Cancer ◽  
Primary Tumor ◽  
Biochemical Recurrence ◽  
Whole Body ◽  
Negative Results ◽  
Primary Prostate Cancer ◽  
Pet Ct ◽  
The Relationship ◽  
Positive Results ◽  
T Category

Purpose: To study the diagnostic value of PET-CT with 68Ga-PSMA-11 in the diagnosis of a primary prostate cancer, preoperative staging, and the detection of recurrence of prostate cancer (PCa). Methods: 28 patients aged 64.7 ± 8.74 years were included. 10 patients primary prostate cancer, and 18 patients with biochemical recurrence of the disease after radical treatment were examined. All patients underwent PET-CT with 68Ga-PSMA-11 according the whole body protocol. Interpretation of images was performed visually and quantitatively by calculation of SUL max. Results: High focal or diffuse 68Ga-PSMA-11 uptake was found in prostate parenchyma in patients with primary prostate cancer. Additionally metastases in regional lymph nodes were diagnosed in 4 patients and bone metastases were found in one patient. The correlation between 68Ga-PSMA-11 uptake level and Gleason index in the primary tumor (R Spearmen = 0.25, p = 0.57) was not observed. PET-positive results were obtained in 14 patients and PET-negative results in 4 patients with biochemical recurrence of PCa. The relationship between the frequency of PET-positive results and Gleason index was not revealed (R Spearmen = 0.2, p = 0.39). We found a weak but significant correlation between the frequency of PET-positive results and the prostate tumor stage according to the T category (R Spearmen = 0.49, p = 0.049). In patients with low values of PSA (less than 1.0 ng/ml) in 4 out of 9 cases, PET-negative results were obtained. In patients with PSA level more than 1.0 ng/ml PET-positive results were obtained in all cases. Conclusions: PET/CT with 68Ga-PSMA-11 allows to diagnose the primary prostate cancer, to establish the stage of the disease in categories N and M, and also to determine the localization and dissemination of the tumor in patients with biochemical recurrence of prostate cancer. The relationship between 68Ga-PSMA-11 uptake in primary tumor and Gleason index was not found. The probability of obtaining PET-positive results in cases of biochemical recurrence is affected by a PSA level above 1 ng/ml and a high stage of the disease according to the T category (T3-T4).

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 Diagnostic Performance of Ankle-Brachial Pressure Index in Lower Extremity Arterial Disease

2021 ◽  
Vol 07 (03) ◽  
pp. e132-e137
Author(s):  
Mohammed Alagha ◽  
Thomas M. Aherne ◽  
Ahmed Hassanin ◽  
Adeel S. Zafar ◽  
Doireann P. Joyce ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Sensitivity And Specificity ◽  
False Negative ◽  
Arterial Disease ◽  
Initial Assessment ◽  
Reference Standard ◽  
Lower Extremity Arterial Disease ◽  
Negative Results ◽  
Positive Results ◽  
Arterial Imaging

Abstract Introduction Ankle-brachial pressure indices (ABIs) continue to form the basis of diagnostics for lower extremity arterial disease (LEAD). However, there remains a paucity of data to support its accuracy. This study aims to evaluate its diagnostic sensitivity and specificity using established arterial-imaging modalities as a benchmark. Methods In this retrospective study, a regional, prospectively maintained, vascular laboratory database was interrogated to identify referred patients with arterial disease who underwent concomitant assessment with ABI and lower limb arterial duplex ultrasound (DUS). Duplex acted as the reference standard. Those who had peripheral computed tomography angiogram (CTA) within 3 months of initial assessment were included in a subgroup analysis to correlate ABI with CTA. The primary end point was the sensitivity and specificity of ABI compared with DUS as the reference standard. Results Concomitant assessment was performed in 438 limbs (250 patients) over a 27-month period. The ABI was normal (0.9 to 1.4) in 196 limbs (44.9%) and abnormal in the remaining 241 limbs (55.1%). False-positive results occurred in 83 out of 241 limbs (34.4%), and false-negative results occurred in 54 limbs out of 196 (27.5%). True-positive results were 158 out of 241 limbs (65.6%), whereas true-negative results were 142 out of 196 limbs (72.4%). ABI using DUS as a benchmark identified a sensitivity for peripheral artery disease of 72.3% and a specificity of 69.3%. Concomitant CTA imaging was available in 200 limbs. The sensitivity and specificity of ABI correlated with CTA were 65.5 and 68.8%, respectively. Conclusion ABIs have a moderate predictive value in the diagnosis of LEAD. Normal range outcomes cannot be taken to infer the absence of LEAD and, as such, further arterial imaging in the form of DUS or angiography should be strongly considered in those with suspected underlying disease requiring intervention. Further noninvasive tests such as exercise studies or pulse volume waveforms should be considered, if diagnostic uncertainty exists, in those requiring nonoperative intervention and risk factor control.

scholarly journals The Interpretation of Studies Using the Reading Level Design

1989 ◽  
Vol 21 (4) ◽  
pp. 413-424 ◽  
Author(s):  
Usha Goswami ◽  
Peter Bryant
Keyword(s):  
Reading Disability ◽  
Reading Level ◽  
Chronological Age ◽  
Control Group ◽  
Causal Factors ◽  
Negative Results ◽  
Level Design ◽  
Positive Results

Recent research in reading disability has been strengthened by the addition of a reading level (RL) control group to the more traditional chronological age (CA) control group. However, caution is required in interpreting results from these two kinds of control. Only positive results in a RL match and negative results in a CA match are interpretable; negative results in a CA match and positive results in a RL match are not. Furthermore, the RL control group cannot be used to unambiguously determine between specific deficit and developmental lag interpretations of reading disability. It is argued that the use of the RL control can only ever be a first step in research aimed at delineating the causal factors in reading backwardness.

scholarly journals Accuracy of brush cytology in biliopancreatic strictures: a single-center cohort study

2021 ◽  
Vol 49 (2) ◽  
pp. 030006052098777
Author(s):  
Song-Ming Ding ◽  
Ai-Li Lu ◽  
Bing-Qian Xu ◽  
Shao-Hua Shi ◽  
Muhammad Ibrahim Alhadi Edoo ◽  
...  
Keyword(s):  
Duct Cell ◽  
Carbohydrate Antigen ◽  
Maximum Diameter ◽  
Biliary Duct ◽  
Brush Cytology ◽  
Tumor Biopsy ◽  
Bile Duct Wall ◽  
Negative Results ◽  
Brushing Cytology ◽  
Positive Results

Objective False positive and negative results are associated with biliary tract cell brushing cytology during endoscopic retrograde cholangiopancreatography (ERCP). The causes are uncertain. The purpose of this study was to evaluate the accuracy of diagnoses made via cell brushing in our center, and to explore the factors influencing diagnosis. Methods The clinical data of patients who underwent cell brushing at our center from January 2016 to August 2019 were retrospectively analyzed. These included age, gender, stricture location, thickness of the bile duct wall in the narrow segment, maximum diameter of the biliary duct above the stricture, number of cell brush smears, carbohydrate antigen 19-9, and carcinoembryonic antigen. Positive brush cytology results were compared with results of surgical histology or tumor biopsy as well as with the patient’s clinical course. Results Of the 48 patients who underwent cell brushing cytology, 27 (56.3%) had positive results. The sensitivity and specificity of biliary duct cell brushing was 79.4%, and 85.7%, respectively. None of the above-mentioned factors were associated with positive cytology brushing results. Conclusions Cell brushing cytology remains a reliable method for diagnosis of pancreaticobiliary malignancies.

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.

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