Incorrect Discrimination Research Articles

Persistent Olfactory and Taste Dysfunction after COVID-19.

(1) Background: One of the possible symptoms of COVID-19 is a sudden loss of smell and taste. The main aim of the study was to evaluate the severity of post-COVID-19 olfactory dysfunction (OD). A secondary aim was to assess the relationship between OD and gustatory (taste) dysfunction (GD). Margins: 2.5 cm (1 inch) at top, bottom, right, and left. (2) Methods: The study group consisted of 81 subjects (16 men and 65 women) aged between 12 and 73 years. All of the patients presented to a center for subjective OD associated with COVID-19. They were tested with a Sniffin' Sticks test (SST) for OD and a Taste Strip test (TS) for GD. (3) Anosmia was present in 18 participants (22%), hyposmia in 52 (64%), and normosmia in 11 (14%). Some 36% of the patients reported imaginary smells (phantosmia), but it did not correlate with olfactory sensitivity. Comparing the different parts of the SST showed that subjects scored lowest on the threshold part of the test. The results of the discrimination and identification parts of the test were better, implying that if the stimulus is intense enough, incorrect discrimination and identification of odors is less frequent. A sweet taste was the easiest to recognize (78% could do so), while the most difficult to recognize was salty (68%). There were weak and statistically non-significant correlations between olfactory and taste dysfunction. (4) Conclusions: The results suggest that post-COVID-19 olfactory dysfunction was more peripheral than central. Testing patients for the severity of post-COVID-19 OD may help clinicians treat the condition. Because there is no fully effective treatment, research on post-COVID-19 OD is needed.

Lightweight Multilevel Feature-Fusion Network for Built-Up Area Mapping from Gaofen-2 Satellite Images

The timely, accurate acquisition of geographic spatial information such as the location, scope, and distribution of built-up areas is of great importance for urban planning, management, and decision-making. Due to the diversity of target features and the complexity of spatial layouts, the large-scale mapping of urban built-up areas using high-resolution (HR) satellite imagery still faces considerable challenges. To address this issue, this study adopted a block-based processing strategy and constructed a lightweight multilevel feature-fusion (FF) convolutional neural network for the feature representation and discrimination of built-up areas in HR images. The proposed network consists of three feature extraction modules composed of lightweight convolutions to extract features at different levels, which are further fused sequentially through two attention-based FF modules. Furthermore, to improve the problem of incorrect discrimination and severe jagged boundaries caused by block-based processing, a majority voting method based on a grid offset is adopted to achieve a refined extraction of built-up areas. The effectiveness of this method is evaluated using Gaofen-2 satellite image data covering Shenzhen, China. Compared with several state-of-the-art algorithms for detecting built-up areas, the proposed method achieves a higher detection accuracy and preserves better shape integrity and boundary smoothness in the extracted results.

Visual awareness judgments are sensitive to accuracy feedback in stimulus discrimination tasks.

In this study we tested the hypothesis that perceptual awareness judgments are sensitive to accuracy feedback about the previous action. We used a perceptual discrimination task in which participants reported their stimulus awareness. We created two conditions: No-feedback and Feedback (discrimination accuracy feedback was provided at the end of each trial). The results showed that visual awareness judgments are related to the accuracy of current and previous responses. Participants reported lower stimulus awareness for incorrectly versus correctly discriminated stimuli in both conditions; they also reported lower stimulus awareness in trials preceded by incorrect discrimination responses, compared to trials preceded by correct discrimination responses. This difference was significantly stronger in the Feedback condition, in which we also observed post-error slowing for PAS ratings. We discuss the relation between visual awareness and the effects of performance monitoring and interpret the results in the context of current theories of consciousness.

Information Accrual From the Period Preceding Racket-Ball Contact for Tennis Ground Strokes: Inferences From Stochastic Masking.

Previous research suggests the existence of an expert anticipatory advantage, whereby skilled sportspeople are able to predict an upcoming action by utilizing cues contained in their opponent’s body kinematics. This ability is often inferred from “occlusion” experiments: information is systematically removed from first-person videos of an opponent, for example, by stopping a tennis video at the point of racket-ball contact, yet performance, such as discrimination of shot direction, remains above chance. In this study, we assessed the expert anticipatory advantage for tennis ground strokes via a modified approach, known as “bubbles,” in which information is randomly removed from videos in each trial. The bubbles profile is then weighted by trial outcome (i.e., a correct vs. incorrect discrimination) and combined across trials into a classification array, revealing the potential cues informing the decision. In two experiments (both with N = 34 skilled tennis players) we utilized either temporal or spatial bubbles, applying them to videos running from 0.8 to 0 s before the point of racket-ball contact (cf. Jalali et al., 2018). Results from the spatial experiment were somewhat suggestive of accrual from the torso region of the body, but were not compelling. Results from the temporal experiment, on the other hand, were clear: information was accrued mainly during the period immediately prior to racket-ball contact. This result is broadly consistent with prior work using nonstochastic approaches to video manipulation, and cannot be an artifact of temporal smear from information accrued after racket-ball contact, because no such information was present.

Automatic discrimination of earthquakes and quarry blasts using wavelet filter bank and support vector machine

False discrimination between earthquakes and quarry blasts may lead to an unrealistic characterization of the natural seismicity of a region. The similarity in seismograms between earthquakes and quarry blasts is the primary reason for incorrect discrimination. Therefore, in this paper, we propose a discriminative algorithm utilizing wavelet filter bank to extract unique features between earthquakes and quarry blasts. The discriminative features are found to be in the first five seconds after the onset time. The proposed algorithm is divided into two stages: first, wavelet filter bank extracts the features of the seismic signals; then, support vector machine classifies the event based on these extracted features. The proposed algorithm achieves a discrimination accuracy of 98.5% when applied to 900 earthquakes and quarry blast waveforms.

Awareness in the crowd: Beta power and alpha phase of prestimulus oscillations predict object discrimination in visual crowding.

Visual crowding is among the factors that most hamper conscious object perception. However, we currently ignore the neural states that predispose to an accurate perception within different crowding regimes. Here, we performed single-trial analyses of the electroencephalographical (EEG) oscillations, evaluating the prestimulus power and phase differences between correct and incorrect discrimination during a letter-crowding task, where irrelevant letters were placed nearby (strong crowding) or far (mid crowding) relative to the target. Results show that prestimulus alpha (8-12Hz) power was related to target discrimination in the mid, but not in the strong, crowding condition. Importantly, accurate discrimination in the strong crowding condition was predicted by the phase of alpha and by the power of beta (13-20Hz) oscillations. These evidence suggest that both periodic visual sampling mechanisms, reflected in the alpha phase, and network predisposition to extract local information, reflected in the beta power, predispose to object discrimination in a crowded scene.

Involuntary orienting of attention to a sound desynchronizes the occipital alpha rhythm and improves visual perception

Directing attention voluntarily to the location of a visual target results in an amplitude reduction (desynchronization) of the occipital alpha rhythm (8–14Hz), which is predictive of improved perceptual processing of the target. Here we investigated whether modulations of the occipital alpha rhythm triggered by the involuntary orienting of attention to a salient but spatially non-predictive sound would similarly influence perception of a subsequent visual target. Target discrimination was more accurate when a sound preceded the target at the same location (validly cued trials) than when the sound was on the side opposite to the target (invalidly cued trials). This behavioral effect was accompanied by a sound-induced desynchronization of the alpha rhythm over the lateral occipital scalp. The magnitude of alpha desynchronization over the hemisphere contralateral to the sound predicted correct discriminations of validly cued targets but not of invalidly cued targets. These results support the conclusion that cue-induced alpha desynchronization over the occipital cortex is a manifestation of a general priming mechanism that improves visual processing and that this mechanism can be activated either by the voluntary or involuntary orienting of attention. Further, the observed pattern of alpha modulations preceding correct and incorrect discriminations of valid and invalid targets suggests that involuntary orienting to the non-predictive sound has a rapid and purely facilitatory influence on processing targets on the cued side, with no inhibitory influence on targets on the opposite side.

Unnatural Contexts Cause Honey Bee Guards to Adopt Non-Guarding Behaviours Towards Allospecifics and Conspecifics

Context plays an important role in a discriminator's ability to make appropriate recognition decisions, such as accepting what is acceptable and rejecting what is not acceptable. Previously it was shown that in both honey bees and stingless bees, discriminating workers (guards) make more errors towards conspecific non-nestmates when the guards are removed from the natural hive entrance. However, it may be that guards, in addition to making incorrect recognition decisions, also may adopt non-guarding behaviours. Here, we tested honey bee guards in two contexts (natural versus unnatural) against five types of introduced arthropods (conspecific nestmates and non-nestmates; allospecific wasps, beetles and woodlice), which should be rejected without error. We scored a guard's response as accept, reject, avoid and ignore. Total errors significantly increased from natural to unnatural contexts. Specifically, guards were significantly more likely to make an acceptance error, guarding and accepting both conspecific and allospecific non-nestmates, in the unnatural context. Importantly, guards were significantly more likely to adopt a non-guarding behaviour in the unnatural context, which usually involved ignoring or avoiding, where a guard makes contact but then immediately retreats, the introduced arthropod. Overall, these data demonstrate the context is important. Removing a guard from the home that it protects elicits either incorrect discrimination or, additionally, a complete lack of discriminator behaviour altogether.

Prestimulus Oscillations in the Alpha Band of the EEG Are Modulated by the Difficulty of Feature Discrimination and Predict Activation of a Sensory Discrimination Process

Recent work has demonstrated that the occipital-temporal N1 component of the ERP is sensitive to the difficulty of visual discrimination, in a manner that cannot be explained by simple differences in low-level visual features, arousal, or time on task. These observations provide evidence that the occipital-temporal N1 component is modulated by the application of top-down control. However, the timing of this control process remains unclear. Previous work has demonstrated proactive, top-down modulation of cortical excitability for cued spatial attention or feature selection tasks. Here, the possibility that a similar top-down process facilitates performance of a difficult stimulus discrimination task is explored. Participants performed an oddball task at two levels of discrimination difficulty, with difficulty manipulated by modulating the similarity between target and nontarget stimuli. Discrimination processes and cortical excitability were assessed via the amplitude of the occipital-temporal N1 component and prestimulus alpha oscillation of the EEG, respectively. For correct discriminations, prestimulus alpha power was reduced, and the occipital-temporal N1 was enhanced in the hard relative to the easy condition. Furthermore, within the hard condition, prestimulus alpha power was reduced, and the occipital-temporal N1 was enhanced for correct relative to incorrect discriminations. The generation of ERPs contingent on relative prestimulus alpha power additionally suggests that diminished alpha power preceding stimulus onset is related to enhancement of the occipital-temporal N1. As in spatial attention, proactive control appears to enhance cortical excitability and facilitate discrimination performance in tasks requiring nonspatial, feature-based attention, even in the absence of competing stimulus features.

Exploring flavour–nutrient learning using a novel paired-discrimination task

Flavours can acquire the capacity to signal nutrient composition and to influence meal size. In humans, attempts to demonstrate this ‘flavour–nutrient learning’ have achieved mixed results. The present studies were designed to explore whether humans have the capacity to discriminate between high (study 1: 113 kcal/100 g; study 2: 98 kcal/100 g) and low energy-dense (study 1: 66 kcal/100 g; study 2: 57.4 kcal/100 g) versions of a novel test food. Two studies were conducted. In each study, participants attended the laboratory on consecutive days. In each session, they consumed a version of the novel food and abstained from eating for 3 h afterwards. In Study 1, purple and orange versions of the test foods were formulated (the pairing between colour and energy density was counterbalanced across participants). In Study 2, both versions of the test food were pink. Importantly, the high and low energy-dense test foods were matched for their sensory characteristics and their portion sizes (g). Allocation of the test foods was counterbalanced across the first and second session. Three hours after the second session, participants returned to the laboratory and were required to identify the order in which they consumed each version. Chi-squared analysis revealed that the number of correct discriminations was not significantly different from the number of incorrect discriminations in both studies (p = 0.763). We attribute this to a general inability to encode and compare appetite across test days.

Cell analysis in cerebrospinal fluid (CSF) using Sysmex® hematology analyzers XT‐4000i and XE‐5000: Evaluation with CSF controls of the Joint German Society for Clinical Chemistry and Laboratory Medicine (DGKL)

In cerebrospinal fluid (CSF) analysis, hematology analyzers (HAs) Sysmex® XT-4000i and XE-5000, equipped with flow cytometry (FCM), were used to count cells and differentiate leukocytes into mononuclear and polymorphonuclear cells (MNCs, PMCs) applying body fluid mode. FCM was evaluated with 20 DGKL CSF controls containing viable human leukocytes and erythrocytes. HA values were compared with reference values by Passing/Bablok regression analysis to reveal conformity. Conformity of white blood cells (WBCs) was obtained with native leukocytes, counted in calibrated Fuchs-Rosenthal chamber as reference; red blood cell counts proved inaccurate. CV <40% with WBC counts <20 per μL impairs accuracy. Reference WBC differentiation was assayed using FACS Canto II™ and FC-500 SN with anti-CD45, anti-CD14, anti-CD16, anti-CD16/56 [Becton Dickinson (BD); Beckman Coulter (BC)]. BD FACS lysing solution®-no-wash-procedure was applied. BC pretreatment with Versalyse lysing solution was not recommended. MNCs (lymphocytes + monocytes) were significantly lower (∼14%) on both HAs; PMCs (granulocytes or sum of neutrophils + eosinophils + basophils: range 1-86 M/L) were significantly higher (∼2.2-fold). WBC HA differentiation is not reliable because MNC/PMC differentiation yielded lower and higher values than FACS-FCM references, respectively. This is attributed to incorrect discrimination of leukocytes with rounded/nonrounded nuclei; adding leukocytes with nonrounded nuclei to too low HA MNCs (about 40% not-activated) yielded P/B conformity; subtraction of leukocytes with nonrounded nuclei from elevated HA PMCs showed conformity (about 85% activated). Nucleus/activation state of leukocytes was assessed using microhistology. Sysmex XT-4000i and XE-5000 HAs systems are inappropriate for complete CSF cell analysis.

You Can't Think and Hit at the Same Time: Neural Correlates of Baseball Pitch Classification.

Hitting a baseball is often described as the most difficult thing to do in sports. A key aptitude of a good hitter is the ability to determine which pitch is coming. This rapid decision requires the batter to make a judgment in a fraction of a second based largely on the trajectory and spin of the ball. When does this decision occur relative to the ball’s trajectory and is it possible to identify neural correlates that represent how the decision evolves over a split second? Using single-trial analysis of electroencephalography (EEG) we address this question within the context of subjects discriminating three types of pitches (fastball, curveball, slider) based on pitch trajectories. We find clear neural signatures of pitch classification and, using signal detection theory, we identify the times of discrimination on a trial-to-trial basis. Based on these neural signatures we estimate neural discrimination distributions as a function of the distance the ball is from the plate. We find all three pitches yield unique distributions, namely the timing of the discriminating neural signatures relative to the position of the ball in its trajectory. For instance, fastballs are discriminated at the earliest points in their trajectory, relative to the two other pitches, which is consistent with the need for some constant time to generate and execute the motor plan for the swing (or inhibition of the swing). We also find incorrect discrimination of a pitch (errors) yields neural sources in Brodmann Area 10, which has been implicated in prospective memory, recall, and task difficulty. In summary, we show that single-trial analysis of EEG yields informative distributions of the relative point in a baseball’s trajectory when the batter makes a decision on which pitch is coming.

1P1-E23 手と手首動作の並列識別を可能とした筋電義手制御法

In the past, we proposed a feature extraction method using quadratic polynomials and a discrimination method using conic models. By this method, open, grip, chuck, wrist extension and wrist flexion can be discriminated at a rate of above 90 percent without the incorrect discrimination that elbow motions cause. However, because this method cannot discriminate both hand motion and wrist motion at the same time, it is like a human hand. In this research, we propose a myoelectric prosthetic hand control method to discriminate parallel both hand motion and wrist motion from EMG signals. In experiment, discrimination accuracies of proposed method were verified. The discrimination accuracies were above 90 percent.

Adaptation in MT neurons shifts speed tuning laterally, facilitating change discrimination

Event Abstract Back to Event Adaptation in MT neurons shifts speed tuning laterally, facilitating change discrimination There is rich information content in the spatial and temporal changes in natural scenes, suggesting that the detection and discrimination of these changes may be critical for generating appropriate behavior. Adaptation improves perceptual sensitivity to stimulus changes and modifies neural responses to sustained stimuli, but it is not clear if and how adaptation improves neural sensitivity to stimulus changes. To address this, we recorded from neurons in area MT of two monkeys while they performed a speed change discrimination task. A circular window of random dots moving in the neuron's preferred direction was presented within the neuron?s receptive field. The dots moved at a 'reference' speed and then abruptly changed to a 'test' speed with change times distributed from 500-5000 ms following a flat hazard function. Monkeys were trained to report the sign of the speed change by saccading to one of two targets within 150-750 ms of the change. Because the task requires both detection and discrimination, trials could end in one of four ways: (1) false detection; (2) correct detection and discrimination; (3) correct detection but incorrect discrimination; and (4) failed detection. We used reference speeds of 8 or 12°/s on each trial, with test speeds of 4-18/s. Psychophysical performance declined with increasing task difficulty: smaller speed changes were associated with more failed detections and longer reaction times. For many neurons, responses to test motion depended strikingly on the reference speed. Speed tuning curves during the task were steeper in slope and laterally shifted relative to those measured during fixation. The shifts were typically 'attractive', moving the flank of the tuning curve towards the adapting ("reference") speed, thus optimizing neural sensitivity for speed discrimination. The size of these shifts correlated with the slope of the speed tuning measured during fixation but not with the preferred speed. This suggests that the neurons most suited to contribute to task performance are those showing the strongest effects of adaptation and with the steepest part of their speed tuning curve near the reference speed. We calculated neurometric performance as the percentage of trials in which the sign of the change in firing rate following a speed change correctly identified the sign of the change in speed. This measure also correlated with the slope of the speed tuning curve, but not the preferred speed, as was found for the speed tuning shifts during the task. Finally, choice probabilities were calculated from false detection trials by comparing firing rate distributions from trials with faster and slower choices. CPs peaked ~200 ms prior to the behavioral response and were largest for cells with the best neurometric performance indicating that the responses of the most informative neurons are those that best predict the behavior of the monkey. These results are consistent with a causal role of MT neurons in detecting and discriminating changes in speed. Conference: Computational and systems neuroscience 2009, Salt Lake City, UT, United States, 26 Feb - 3 Mar, 2009. Presentation Type: Poster Presentation Topic: Poster Presentations Citation: (2009). Adaptation in MT neurons shifts speed tuning laterally, facilitating change discrimination. Front. Syst. Neurosci. Conference Abstract: Computational and systems neuroscience 2009. doi: 10.3389/conf.neuro.06.2009.03.142 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 Feb 2009; Published Online: 02 Feb 2009. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Google Google Scholar PubMed Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

The path to success in auditory spatial discrimination: Electrical neuroimaging responses within the supratemporal plane predict performance outcome

Auditory scene analysis requires the accurate encoding and comparison of the perceived spatial positions of sound sources. The electrophysiological correlates of auditory spatial discrimination and their relationship to performance accuracy were studied in humans by applying electrical neuroimaging analyses to auditory evoked potentials (AEPs) that were recorded during the completion of a near-threshold S1–S2 paradigm within the right hemispace. Data were sorted as a function of performance accuracy, and AEP responses 75–117 ms after the presentation of the first sound differed topographically between trials leading to correct and incorrect spatial discrimination. Distributed source estimations revealed that this followed from significantly stronger activity within the left (i.e. contralateral) supratemporal plane (STP) and the left inferior parietal lobule prior to correct versus incorrect discrimination performance. Successful spatial discrimination thus depends on the activity of distinct configurations of active brain networks within the contralateral temporo-parietal cortex over a time period when the first sound position is being encoded. Furthermore, significant positive correlations were observed between performance accuracy and the intracranial activity estimated within the left STP. The efficacy of S1 processing within the STP is thus predictive of behavioral performance outcome during auditory spatial discrimination. Our data support a model wherein refinement of spatial representations occurs within the STP and that interactions with parietal structures allow for transformations into coordinate frames that are required for higher-order computations including absolute localization of sound sources.

Molecular Authentication of the Animal Crude Drug Sailonggu (Bone of Myospalax baileyi)

Two pairs of allele-specific diagnostic primers (SL1L/SL1H and SL2L/SL2H) for distinguishing the Chinese crude drug Sailonggu (bone of plateau zokor, Myospalax baileyi) from its substitutes were designed based on complete sequences of mitochondrial 12S rRNA and cytochrome b genes of the original animals of Myospalacinae, bamboo rat Rhizomys sinensis and black lipped pika Ochotona curzoniae. Total DNA was extracted from crude drug samples and original animals. Allele-specific diagnostic PCRs were performed using these primers with the total DNA as a template annealing at 65 degrees C. Positive amplifications were obtained from all DNA templates of Sailonggu and M. baileyi, whereas negative amplifications resulted from those of other zokors, the bamboo rat and black lipped pika. These results indicate that Sailonggu samples can be definitely distinguished from their substitutes by diagnostic PCR, and no incorrect discrimination was found under the same reaction conditions. Each of the two diagnostic primer pairs can be used to distinguish crude drug Sailonggu from its substitutes or adulterants. The three Sailonggu samples studied were diagnosed as genuine Sailonggu. In addition, the results of sequence alignment and phylogenetic analysis are congruent with that of the allele-specific diagnostic PCR.

Establishing reports of saying and doing and discriminations of say–do relations

The purpose of the present study was to investigate a new procedure for establishing accurate discriminations of delayed acts of saying, of doing and discriminations of say–do correspondence and non-correspondence with three developmentally delayed subjects. A corrective feedback procedure for incorrect discrimination responses, that involved multiple-exemplars, was initially employed, but failed to establish most of the target discriminations for all three subjects. A near-errorless training intervention was subsequently employed that also involved multiple-exemplars. This training used two referents (one for acts of saying and another one for acts of doing) as prompts to produce accurate delayed reports of what they promise to do presently, and accurate delayed reports of what they did. Prompts were also used to indicate whether the say–do relations were the ‘same’ in terms of correspondence or not the same in terms of non-correspondence. Prompts were subsequently eliminated. All three subjects demonstrated highly accurate reports of delayed saying, doing and say–do correspondence or non-correspondence discriminations in the absence of prompts and with novel stimuli. The results are discussed in terms of generalized classes of behavior. The implications of these findings for the use of the errorless learning paradigm as a means of establishing complex behavior are also discussed.

PCR-based sensitive detection of medicinal fungi Hericium species from ribosomal internal transcribed spacer (ITS) sequences.

Based on phylogenetic analysis of rDNA internal transcribed spacer (ITS) sequences, a pair of specific primers were designed for differentiating the Chinese traditional medicine Hericium species from other mushrooms by PCR. PCR was performed, with total DNAs as a template at an annealing temperature of 52-57 degrees C. Positive amplification was obtained from H. erinaceus with all DNA templates from different resources, but not from other related species. The result indicated that H. erinaceus could be clearly distinguished from other fungi by detection PCR, and no incorrect discrimination was found under the same reaction conditions. The primers were also successfully employed to identify H. erinaceus with different tissue types.

Authentication of an animal crude drug, Zaocys, by diagnostic PCR.

A pair of diagnostic primers for distinguishing the Chinese crude drug Zaocys (Zaocys dhumandes) from its substitutes was designed based on the sequence data of the original animal of the drug and substitutes. Total DNAs were extracted from genuine crude drug and 5 of its substitutes, as well as from 12 species of original animal of the snake crude drug. Diagnostic PCRs were performed using the primers with these total DNAs as a template, annealing at 60-65 degrees C. Positive amplifications were obtained from all DNA templates of Zaocys, whereas negative amplifications were obtained from that of others. The results indicate that Zaocys samples could be definitely distinguished from its substitutes by diagnostic PCR, and no incorrect discrimination was found under the same reaction conditions. The advantages of the method in the authentication of crude drugs are also discussed in the present paper.

Predicting renal stone fragility against ESWL

The mineral content (MC) and mineral density (MD) of renal stones, measured by dual energy X-ray absorptiometry, were compared with the experimental and clinical results of stone disintegration by shock wave. In the experimental study, the MC and MD values correlated significantly with the total shock wave energy used, with a correlation coefficient (r) for MC being 0.814 and for MD, 0.706 (n = 46). The mean MC and MD values were 0.521 +/- 0.387g and 0.317 +/- 0.121 g/cm2 (n = 14) respectively in patients undergoing clinically successful ESWL, while those were 4.27 +/- 6.19g and 0.626 +/- 0.302 g/cm2 (n = 6) respectively in patients undergoing clinically unsuccessful ESWL. Those values differed significantly between the two groups (p < 0.05, p < 0.01, respectively). The combination of MC, MD and area values of a stone was shown to be the best predictor of treatment outcome, with a predictive value of incorrect discrimination being 17% and that of correct discrimination, 85% using linear discriminant analysis. The mineral content and mineral density, measured by dual energy X-ray absorptiometry, may provide the best prediction of outcome of patients undergoing ESWL treatment.