Rhesus monkeys (Macaca mulatta) show robust primacy and recency in memory for lists from small, but not large, image sets.

PubMed

Basile, Benjamin M; Hampton, Robert R

2010-02-01

The combination of primacy and recency produces a U-shaped serial position curve typical of memory for lists. In humans, primacy is often thought to result from rehearsal, but there is little evidence for rehearsal in nonhumans. To further evaluate the possibility that rehearsal contributes to primacy in monkeys, we compared memory for lists of familiar stimuli (which may be easier to rehearse) to memory for unfamiliar stimuli (which are likely difficult to rehearse). Six rhesus monkeys saw lists of five images drawn from either large, medium, or small image sets. After presentation of each list, memory for one item was assessed using a serial probe recognition test. Across four experiments, we found robust primacy and recency with lists drawn from small and medium, but not large, image sets. This finding is consistent with the idea that familiar items are easier to rehearse and that rehearsal contributes to primacy, warranting further study of the possibility of rehearsal in monkeys. However, alternative interpretations are also viable and are discussed. Copyright 2009 Elsevier B.V. All rights reserved.

Language and Short-Term Memory: The Role of Perceptual-Motor Affordance

PubMed Central

2014-01-01

The advantage for real words over nonwords in serial recall—the lexicality effect—is typically attributed to support for item-level phonology, either via redintegration, whereby partially degraded short-term traces are “cleaned up” via support from long-term representations of the phonological material or via the more robust temporary activation of long-term lexical phonological knowledge that derives from its combination with established lexical and semantic levels of representation. The much smaller effect of lexicality in serial recognition, where the items are re-presented in the recognition cue, is attributed either to the minimal role for redintegration from long-term memory or to the minimal role for item memory itself in such retrieval conditions. We show that the reduced lexicality effect in serial recognition is not a function of the retrieval conditions, but rather because previous demonstrations have used auditory presentation, and we demonstrate a robust lexicality effect for visual serial recognition in a setting where auditory presentation produces no such effect. Furthermore, this effect is abolished under conditions of articulatory suppression. We argue that linguistic knowledge affects the readiness with which verbal material is segmentally recoded via speech motor processes that support rehearsal and therefore affects tasks that involve recoding. On the other hand, auditory perceptual organization affords sequence matching in the absence of such a requirement for segmental recoding and therefore does not show such effects of linguistic knowledge. PMID:24797440

Language and short-term memory: the role of perceptual-motor affordance.

PubMed

Macken, Bill; Taylor, John C; Jones, Dylan M

2014-09-01

The advantage for real words over nonwords in serial recall--the lexicality effect--is typically attributed to support for item-level phonology, either via redintegration, whereby partially degraded short-term traces are "cleaned up" via support from long-term representations of the phonological material or via the more robust temporary activation of long-term lexical phonological knowledge that derives from its combination with established lexical and semantic levels of representation. The much smaller effect of lexicality in serial recognition, where the items are re-presented in the recognition cue, is attributed either to the minimal role for redintegration from long-term memory or to the minimal role for item memory itself in such retrieval conditions. We show that the reduced lexicality effect in serial recognition is not a function of the retrieval conditions, but rather because previous demonstrations have used auditory presentation, and we demonstrate a robust lexicality effect for visual serial recognition in a setting where auditory presentation produces no such effect. Furthermore, this effect is abolished under conditions of articulatory suppression. We argue that linguistic knowledge affects the readiness with which verbal material is segmentally recoded via speech motor processes that support rehearsal and therefore affects tasks that involve recoding. On the other hand, auditory perceptual organization affords sequence matching in the absence of such a requirement for segmental recoding and therefore does not show such effects of linguistic knowledge.

Target recognition of ladar range images using even-order Zernike moments.

PubMed

Liu, Zheng-Jun; Li, Qi; Xia, Zhi-Wei; Wang, Qi

2012-11-01

Ladar range images have attracted considerable attention in automatic target recognition fields. In this paper, Zernike moments (ZMs) are applied to classify the target of the range image from an arbitrary azimuth angle. However, ZMs suffer from high computational costs. To improve the performance of target recognition based on small samples, even-order ZMs with serial-parallel backpropagation neural networks (BPNNs) are applied to recognize the target of the range image. It is found that the rotation invariance and classified performance of the even-order ZMs are both better than for odd-order moments and for moments compressed by principal component analysis. The experimental results demonstrate that combining the even-order ZMs with serial-parallel BPNNs can significantly improve the recognition rate for small samples.

Scanning probe recognition microscopy investigation of tissue scaffold properties

PubMed Central

Fan, Yuan; Chen, Qian; Ayres, Virginia M; Baczewski, Andrew D; Udpa, Lalita; Kumar, Shiva

2007-01-01

Scanning probe recognition microscopy is a new scanning probe microscopy technique which enables selective scanning along individual nanofibers within a tissue scaffold. Statistically significant data for multiple properties can be collected by repetitively fine-scanning an identical region of interest. The results of a scanning probe recognition microscopy investigation of the surface roughness and elasticity of a series of tissue scaffolds are presented. Deconvolution and statistical methods were developed and used for data accuracy along curved nanofiber surfaces. Nanofiber features were also independently analyzed using transmission electron microscopy, with results that supported the scanning probe recognition microscopy-based analysis. PMID:18203431

Scanning probe recognition microscopy investigation of tissue scaffold properties.

PubMed

Fan, Yuan; Chen, Qian; Ayres, Virginia M; Baczewski, Andrew D; Udpa, Lalita; Kumar, Shiva

2007-01-01

Scanning probe recognition microscopy is a new scanning probe microscopy technique which enables selective scanning along individual nanofibers within a tissue scaffold. Statistically significant data for multiple properties can be collected by repetitively fine-scanning an identical region of interest. The results of a scanning probe recognition microscopy investigation of the surface roughness and elasticity of a series of tissue scaffolds are presented. Deconvolution and statistical methods were developed and used for data accuracy along curved nanofiber surfaces. Nanofiber features were also independently analyzed using transmission electron microscopy, with results that supported the scanning probe recognition microscopy-based analysis.

Dyslexic children show short-term memory deficits in phonological storage and serial rehearsal: an fMRI study.

PubMed

Beneventi, Harald; Tønnessen, Finn Egil; Ersland, Lars

2009-01-01

Dyslexia is primarily associated with a phonological processing deficit. However, the clinical manifestation also includes a reduced verbal working memory (WM) span. It is unclear whether this WM impairment is caused by the phonological deficit or a distinct WM deficit. The main aim of this study was to investigate neuronal activation related to phonological storage and rehearsal of serial order in WM in a sample of 13-year-old dyslexic children compared with age-matched nondyslexic children. A sequential verbal WM task with two tasks was used. In the Letter Probe task, the probe consisted of a single letter and the judgment was for the presence or absence of that letter in the prior sequence of six letters. In the Sequence Probe (SP) task, the probe consisted of all six letters and the judgment was for a match of their serial order with the temporal order in the prior sequence. Group analyses as well as single-subject analysis were performed with the statistical parametric mapping software SPM2. In the Letter Probe task, the dyslexic readers showed reduced activation in the left precentral gyrus (BA6) compared to control group. In the Sequence Probe task, the dyslexic readers showed reduced activation in the prefrontal cortex and the superior parietal cortex (BA7) compared to the control subjects. Our findings suggest that a verbal WM impairment in dyslexia involves an extended neural network including the prefrontal cortex and the superior parietal cortex. Reduced activation in the left BA6 in both the Letter Probe and Sequence Probe tasks may be caused by a deficit in phonological processing. However, reduced bilateral activation in the BA7 in the Sequence Probe task only could indicate a distinct working memory deficit in dyslexia associated with temporal order processing.

Auditory Word Serial Recall Benefits from Orthographic Dissimilarity

ERIC Educational Resources Information Center

Pattamadilok, Chotiga; Lafontaine, Helene; Morais, Jose; Kolinsky, Regine

2010-01-01

The influence of orthographic knowledge has been consistently observed in speech recognition and metaphonological tasks. The present study provides data suggesting that such influence also pervades other cognitive domains related to language abilities, such as verbal working memory. Using serial recall of auditory seven-word lists, we observed…

NASA Tech Briefs, August 2003

NASA Technical Reports Server (NTRS)

2003-01-01

Topics covered include: Stable, Thermally Conductive Fillers for Bolted Joints; Connecting to Thermocouples with Fewer Lead Wires; Zipper Connectors for Flexible Electronic Circuits; Safety Interlock for Angularly Misdirected Power Tool; Modular, Parallel Pulse-Shaping Filter Architectures; High-Fidelity Piezoelectric Audio Device; Photovoltaic Power Station with Ultracapacitors for Storage; Time Analyzer for Time Synchronization and Monitor of the Deep Space Network; Program for Computing Albedo; Integrated Software for Analyzing Designs of Launch Vehicles; Abstract-Reasoning Software for Coordinating Multiple Agents; Software Searches for Better Spacecraft-Navigation Models; Software for Partly Automated Recognition of Targets; Antistatic Polycarbonate/Copper Oxide Composite; Better VPS Fabrication of Crucibles and Furnace Cartridges; Burn-Resistant, Strong Metal-Matrix Composites; Self-Deployable Spring-Strip Booms; Explosion Welding for Hermetic Containerization; Improved Process for Fabricating Carbon Nanotube Probes; Automated Serial Sectioning for 3D Reconstruction; and Parallel Subconvolution Filtering Architectures.

Using Serial and Discrete Digit Naming to Unravel Word Reading Processes

PubMed Central

Altani, Angeliki; Protopapas, Athanassios; Georgiou, George K.

2018-01-01

During reading acquisition, word recognition is assumed to undergo a developmental shift from slow serial/sublexical processing of letter strings to fast parallel processing of whole word forms. This shift has been proposed to be detected by examining the size of the relationship between serial- and discrete-trial versions of word reading and rapid naming tasks. Specifically, a strong association between serial naming of symbols and single word reading suggests that words are processed serially, whereas a strong association between discrete naming of symbols and single word reading suggests that words are processed in parallel as wholes. In this study, 429 Grade 1, 3, and 5 English-speaking Canadian children were tested on serial and discrete digit naming and word reading. Across grades, single word reading was more strongly associated with discrete naming than with serial naming of digits, indicating that short high-frequency words are processed as whole units early in the development of reading ability in English. In contrast, serial naming was not a unique predictor of single word reading across grades, suggesting that within-word sequential processing was not required for the successful recognition for this set of words. Factor mixture analysis revealed that our participants could be clustered into two classes, namely beginning and more advanced readers. Serial naming uniquely predicted single word reading only among the first class of readers, indicating that novice readers rely on a serial strategy to decode words. Yet, a considerable proportion of Grade 1 students were assigned to the second class, evidently being able to process short high-frequency words as unitized symbols. We consider these findings together with those from previous studies to challenge the hypothesis of a binary distinction between serial/sublexical and parallel/lexical processing in word reading. We argue instead that sequential processing in word reading operates on a continuum, depending on the level of reading proficiency, the degree of orthographic transparency, and word-specific characteristics. PMID:29706918

Using Serial and Discrete Digit Naming to Unravel Word Reading Processes.

PubMed

Altani, Angeliki; Protopapas, Athanassios; Georgiou, George K

2018-01-01

During reading acquisition, word recognition is assumed to undergo a developmental shift from slow serial/sublexical processing of letter strings to fast parallel processing of whole word forms. This shift has been proposed to be detected by examining the size of the relationship between serial- and discrete-trial versions of word reading and rapid naming tasks. Specifically, a strong association between serial naming of symbols and single word reading suggests that words are processed serially, whereas a strong association between discrete naming of symbols and single word reading suggests that words are processed in parallel as wholes. In this study, 429 Grade 1, 3, and 5 English-speaking Canadian children were tested on serial and discrete digit naming and word reading. Across grades, single word reading was more strongly associated with discrete naming than with serial naming of digits, indicating that short high-frequency words are processed as whole units early in the development of reading ability in English. In contrast, serial naming was not a unique predictor of single word reading across grades, suggesting that within-word sequential processing was not required for the successful recognition for this set of words. Factor mixture analysis revealed that our participants could be clustered into two classes, namely beginning and more advanced readers. Serial naming uniquely predicted single word reading only among the first class of readers, indicating that novice readers rely on a serial strategy to decode words. Yet, a considerable proportion of Grade 1 students were assigned to the second class, evidently being able to process short high-frequency words as unitized symbols. We consider these findings together with those from previous studies to challenge the hypothesis of a binary distinction between serial/sublexical and parallel/lexical processing in word reading. We argue instead that sequential processing in word reading operates on a continuum, depending on the level of reading proficiency, the degree of orthographic transparency, and word-specific characteristics.

Episodic Short-Term Recognition Requires Encoding into Visual Working Memory: Evidence from Probe Recognition after Letter Report

PubMed Central

Poth, Christian H.; Schneider, Werner X.

2016-01-01

Human vision is organized in discrete processing episodes (e.g., eye fixations or task-steps). Object information must be transmitted across episodes to enable episodic short-term recognition: recognizing whether a current object has been seen in a previous episode. We ask whether episodic short-term recognition presupposes that objects have been encoded into capacity-limited visual working memory (VWM), which retains visual information for report. Alternatively, it could rely on the activation of visual features or categories that occurs before encoding into VWM. We assessed the dependence of episodic short-term recognition on VWM by a new paradigm combining letter report and probe recognition. Participants viewed displays of 10 letters and reported as many as possible after a retention interval (whole report). Next, participants viewed a probe letter and indicated whether it had been one of the 10 letters (probe recognition). In Experiment 1, probe recognition was more accurate for letters that had been encoded into VWM (reported letters) compared with non-encoded letters (non-reported letters). Interestingly, those letters that participants reported in their whole report had been near to one another within the letter displays. This suggests that the encoding into VWM proceeded in a spatially clustered manner. In Experiment 2, participants reported only one of 10 letters (partial report) and probes either referred to this letter, to letters that had been near to it, or far from it. Probe recognition was more accurate for near than for far letters, although none of these letters had to be reported. These findings indicate that episodic short-term recognition is constrained to a small number of simultaneously presented objects that have been encoded into VWM. PMID:27713722

Episodic Short-Term Recognition Requires Encoding into Visual Working Memory: Evidence from Probe Recognition after Letter Report.

PubMed

Poth, Christian H; Schneider, Werner X

2016-01-01

Human vision is organized in discrete processing episodes (e.g., eye fixations or task-steps). Object information must be transmitted across episodes to enable episodic short-term recognition: recognizing whether a current object has been seen in a previous episode. We ask whether episodic short-term recognition presupposes that objects have been encoded into capacity-limited visual working memory (VWM), which retains visual information for report. Alternatively, it could rely on the activation of visual features or categories that occurs before encoding into VWM. We assessed the dependence of episodic short-term recognition on VWM by a new paradigm combining letter report and probe recognition. Participants viewed displays of 10 letters and reported as many as possible after a retention interval (whole report). Next, participants viewed a probe letter and indicated whether it had been one of the 10 letters (probe recognition). In Experiment 1, probe recognition was more accurate for letters that had been encoded into VWM (reported letters) compared with non-encoded letters (non-reported letters). Interestingly, those letters that participants reported in their whole report had been near to one another within the letter displays. This suggests that the encoding into VWM proceeded in a spatially clustered manner. In Experiment 2, participants reported only one of 10 letters (partial report) and probes either referred to this letter, to letters that had been near to it, or far from it. Probe recognition was more accurate for near than for far letters, although none of these letters had to be reported. These findings indicate that episodic short-term recognition is constrained to a small number of simultaneously presented objects that have been encoded into VWM.

Speeded Probed Recall Is Affected by Grouping.

PubMed

Morra, Sergio; Epidendio, Valentina

2015-01-01

Most of the evidence from previous studies on speeded probed recall supported primacy-gradient models of serial order representation. Two experiments investigated the effect of grouping on speeded probed recall. Six-word lists, followed by a number between 1 and 6, were presented for speeded recall of the word in the position indicated by the number. Grouping was manipulated through interstimulus intervals. In both experiments, a significant Position × Grouping interaction was found in RT. It is concluded that the results are not consistent with models of order representation only based on a primacy gradient. Possible alternative representations of serial order are also discussed; a case is made for a holistic order representation.

Memory and event-related potentials for rapidly presented emotional pictures.

PubMed

Versace, Francesco; Bradley, Margaret M; Lang, Peter J

2010-08-01

Dense array event-related potentials (ERPs) and memory performance were assessed following rapid serial visual presentation (RSVP) of emotional and neutral pictures. Despite the extremely brief presentation, emotionally arousing pictures prompted an enhanced negative voltage over occipital sensors, compared to neutral pictures, replicating previous encoding effects. Emotionally arousing pictures were also remembered better in a subsequent recognition test, with higher hit rates and better discrimination performance. ERPs measured during the recognition test showed both an early (250-350 ms) frontally distributed difference between hits and correct rejections, and a later (400-500 ms), more centrally distributed difference, consistent with effects of recognition on ERPs typically found using slower presentation rates. The data are consistent with the hypothesis that features of affective pictures pop out during rapid serial visual presentation, prompting better memory performance.

Learning to recognize face shapes through serial exploration.

PubMed

Wallraven, Christian; Whittingstall, Lisa; Bülthoff, Heinrich H

2013-05-01

Human observers are experts at visual face recognition due to specialized visual mechanisms for face processing that evolve with perceptual expertize. Such expertize has long been attributed to the use of configural processing, enabled by fast, parallel information encoding of the visual information in the face. Here we tested whether participants can learn to efficiently recognize faces that are serially encoded-that is, when only partial visual information about the face is available at any given time. For this, ten participants were trained in gaze-restricted face recognition in which face masks were viewed through a small aperture controlled by the participant. Tests comparing trained with untrained performance revealed (1) a marked improvement in terms of speed and accuracy, (2) a gradual development of configural processing strategies, and (3) participants' ability to rapidly learn and accurately recognize novel exemplars. This performance pattern demonstrates that participants were able to learn new strategies to compensate for the serial nature of information encoding. The results are discussed in terms of expertize acquisition and relevance for other sensory modalities relying on serial encoding.

An Exemplar-Familiarity Model Predicts Short-Term and Long-Term Probe Recognition across Diverse Forms of Memory Search

ERIC Educational Resources Information Center

Nosofsky, Robert M.; Cox, Gregory E.; Cao, Rui; Shiffrin, Richard M.

2014-01-01

Experiments were conducted to test a modern exemplar-familiarity model on its ability to account for both short-term and long-term probe recognition within the same memory-search paradigm. Also, making connections to the literature on attention and visual search, the model was used to interpret differences in probe-recognition performance across…

Who is who: Italian norms for visual recognition and identification of celebrities.

PubMed

Bizzozero, I; Ferrari, F; Pozzoli, S; Saetti, M C; Spinnler, H

2005-06-01

Age-, education- and sex-adjusted norms are provided for two new neuropsychological tests, namely (i) Face Recognition (guess of familiarity) and (ii) Person Identification (biographical contextualisation). Sixty-three pictures of celebrities and 63 of unknown people were selected following two interwoven criteria(1): the realm of their celebrity (i.e., entertainment, culture and politics) and the period of celebrity acquisition (i.e., pre-war, post-war and contemporary). Both media- and education-dependent knowledge of celebrity were considered. Ninety-eight unpaid healthy participants aged between 50 and 93 years and with at least 8 years of formal education took part in this study. Reference is made to serial models of familiar face/persons processing. Recognition is held to tackle the activity of Personal Identity Nodes (PINs) and identification of the Exemplar Semantics Archives. Given the seriality of the reference model, the Identification Test is embedded in the Recognition test. This entailed that only previously recognised faces were employed to achieve norms for identification.

Speech Recognition in Adults With Cochlear Implants: The Effects of Working Memory, Phonological Sensitivity, and Aging.

PubMed

Moberly, Aaron C; Harris, Michael S; Boyce, Lauren; Nittrouer, Susan

2017-04-14

Models of speech recognition suggest that "top-down" linguistic and cognitive functions, such as use of phonotactic constraints and working memory, facilitate recognition under conditions of degradation, such as in noise. The question addressed in this study was what happens to these functions when a listener who has experienced years of hearing loss obtains a cochlear implant. Thirty adults with cochlear implants and 30 age-matched controls with age-normal hearing underwent testing of verbal working memory using digit span and serial recall of words. Phonological capacities were assessed using a lexical decision task and nonword repetition. Recognition of words in sentences in speech-shaped noise was measured. Implant users had only slightly poorer working memory accuracy than did controls and only on serial recall of words; however, phonological sensitivity was highly impaired. Working memory did not facilitate speech recognition in noise for either group. Phonological sensitivity predicted sentence recognition for implant users but not for listeners with normal hearing. Clinical speech recognition outcomes for adult implant users relate to the ability of these users to process phonological information. Results suggest that phonological capacities may serve as potential clinical targets through rehabilitative training. Such novel interventions may be particularly helpful for older adult implant users.

Speech Recognition in Adults With Cochlear Implants: The Effects of Working Memory, Phonological Sensitivity, and Aging

PubMed Central

Harris, Michael S.; Boyce, Lauren; Nittrouer, Susan

2017-01-01

Purpose Models of speech recognition suggest that “top-down” linguistic and cognitive functions, such as use of phonotactic constraints and working memory, facilitate recognition under conditions of degradation, such as in noise. The question addressed in this study was what happens to these functions when a listener who has experienced years of hearing loss obtains a cochlear implant. Method Thirty adults with cochlear implants and 30 age-matched controls with age-normal hearing underwent testing of verbal working memory using digit span and serial recall of words. Phonological capacities were assessed using a lexical decision task and nonword repetition. Recognition of words in sentences in speech-shaped noise was measured. Results Implant users had only slightly poorer working memory accuracy than did controls and only on serial recall of words; however, phonological sensitivity was highly impaired. Working memory did not facilitate speech recognition in noise for either group. Phonological sensitivity predicted sentence recognition for implant users but not for listeners with normal hearing. Conclusion Clinical speech recognition outcomes for adult implant users relate to the ability of these users to process phonological information. Results suggest that phonological capacities may serve as potential clinical targets through rehabilitative training. Such novel interventions may be particularly helpful for older adult implant users. PMID:28384805

A Survey on Banknote Recognition Methods by Various Sensors

PubMed Central

Lee, Ji Woo; Hong, Hyung Gil; Kim, Ki Wan; Park, Kang Ryoung

2017-01-01

Despite a decrease in the use of currency due to the recent growth in the use of electronic financial transactions, real money transactions remain very important in the global market. While performing transactions with real money, touching and counting notes by hand, is still a common practice in daily life, various types of automated machines, such as ATMs and banknote counters, are essential for large-scale and safe transactions. This paper presents studies that have been conducted in four major areas of research (banknote recognition, counterfeit banknote detection, serial number recognition, and fitness classification) in the accurate banknote recognition field by various sensors in such automated machines, and describes the advantages and drawbacks of the methods presented in those studies. While to a limited extent some surveys have been presented in previous studies in the areas of banknote recognition or counterfeit banknote recognition, this paper is the first of its kind to review all four areas. Techniques used in each of the four areas recognize banknote information (denomination, serial number, authenticity, and physical condition) based on image or sensor data, and are actually applied to banknote processing machines across the world. This study also describes the technological challenges faced by such banknote recognition techniques and presents future directions of research to overcome them. PMID:28208733

Test Sequence Priming in Recognition Memory

ERIC Educational Resources Information Center

Johns, Elizabeth E.; Mewhort, D. J. K.

2009-01-01

The authors examined priming within the test sequence in 3 recognition memory experiments. A probe primed its successor whenever both probes shared a feature with the same studied item ("interjacent priming"), indicating that the study item like the probe is central to the decision. Interjacent priming occurred even when the 2 probes did…

Flexibility within working memory and the focus of attention for sequential verbal information does not depend on active maintenance.

PubMed

Sandry, Joshua; Schwark, Jeremy D; MacDonald, Justin

2014-10-01

The focus of attention seems to be a static element within working memory when verbal information is serially presented, unless additional time is available for processing or active maintenance. Experiment 1 manipulated the reward associated with early and medial list positions in a probe recognition paradigm and found evidence that these nonterminal list positions could be retrieved faster and more accurately if participants were appropriately motivated-without additional time for processing or active maintenance. Experiment 2 used articulatory suppression and demonstrated that the underlying maintenance mechanism cannot be attributed to rehearsal, leaving attentional refreshing as the more likely mechanism. These findings suggest that the focus of attention within working memory can flexibly maintain nonterminal early and medial list representations at the expense of other list representations even when there is not additional time for processing or active maintenance. Maintenance seems to be accomplished through an attentional refreshing mechanism.

Detection of restriction fragment length polymorphisms in clinical isolates and serially passaged Pseudomonas aeruginosa strains.

PubMed Central

Hjelm, L N; Branstrom, A A; Warren, R L

1990-01-01

An 800-base-pair HindIII-PstI fragment that flanks a hot spot for Tn7 insertion was isolated from the chromosome of Pseudomonas aeruginosa and cloned into pUC12. The fragment was used to probe XhoI digests of genomic DNA from 18 P. aeruginosa isolates collected from sputum samples of seven cystic fibrosis patients. Only two XhoI restriction fragment length polymorphisms (RFLPs), of 3.7 and 7.7 kilobases (kb), were detected. Isolate WSU3531-1 (3.7-kb XhoI fragment) and WSU3860 (7.7-kb XhoI fragment), while isolated from the same patient, showed different RFLPs. Serial passages of isolate WSU3531-1 demonstrated that this strain was phenotypically stable. In contrast, colony and pigment variants were readily isolated at a frequency of 1% from serial passages of isolate WSU3860. When XhoI-digested genomic DNA from phenotypic variants of serially passaged WSU3860 were probed with the 800-base-pair HindIII-PstI fragment, the probe hybridized to a 10.4-kb XhoI fragment from three isolates. Restriction analysis of the genomic DNA digested with a variety of restriction enzymes showed that a 2.7-kb insertion occurred in the same region for all three isolates. There appeared to be no correlation between changes in the RFLP and changes in colony morphology. Images PMID:1977762

Verbal Serial List Learning in Mild Cognitive Impairment: A Profile Analysis of Interference, Forgetting, and Errors

PubMed Central

Libon, David J.; Bondi, Mark W.; Price, Catherine C.; Lamar, Melissa; Eppig, Joel; Wambach, Denene M.; Nieves, Christine; Delano-Wood, Lisa; Giovannetti, Tania; Lippa, Carol; Kabasakalian, Anahid; Cosentino, Stephanie; Swenson, Rod; Penney, Dana L.

2012-01-01

Using cluster analysis Libon et al. (2010) found three verbal serial list-learning profiles involving delay memory test performance in patients with mild cognitive impairment (MCI). Amnesic MCI (aMCI) patients presented with low scores on delay free recall and recognition tests; mixed MCI (mxMCI) patients scored higher on recognition compared to delay free recall tests; and dysexecutive MCI (dMCI) patients generated relatively intact scores on both delay test conditions. The aim of the current research was to further characterize memory impairment in MCI by examining forgetting/savings, interference from a competing word list, intrusion errors/perseverations, intrusion word frequency, and recognition foils in these three statistically determined MCI groups compared to normal control (NC) participants. The aMCI patients exhibited little savings, generated more highly prototypic intrusion errors, and displayed indiscriminate responding to delayed recognition foils. The mxMCI patients exhibited higher saving scores, fewer and less prototypic intrusion errors, and selectively endorsed recognition foils from the interference list. dMCI patients also selectively endorsed recognition foils from the interference list but performed similarly compared to NC participants. These data suggest the existence of distinct memory impairments in MCI and caution against the routine use of a single memory test score to operationally define MCI. PMID:21880171

Short- and long-term memory contributions to immediate serial recognition: evidence from serial position effects.

PubMed

Purser, Harry; Jarrold, Christopher

2010-04-01

A long-standing body of research supports the existence of separable short- and long-term memory systems, relying on phonological and semantic codes, respectively. The aim of the current study was to measure the contribution of long-term knowledge to short-term memory performance by looking for evidence of phonologically and semantically coded storage within a short-term recognition task, among developmental samples. Each experimental trial presented 4-item lists. In Experiment 1 typically developing children aged 5 to 6 years old showed evidence of phonologically coded storage across all 4 serial positions, but evidence of semantically coded storage at Serial Positions 1 and 2. In a further experiment, a group of individuals with Down syndrome was investigated as a test case that might be expected to use semantic coding to support short-term storage, but these participants showed no evidence of semantically coded storage and evidenced phonologically coded storage only at Serial Position 4, suggesting that individuals with Down syndrome have a verbal short-term memory capacity of 1 item. Our results suggest that previous evidence of semantic effects on "short-term memory performance" does not reflect semantic coding in short-term memory itself, and provide an experimental method for researchers wishing to take a relatively pure measure of verbal short-term memory capacity, in cases where rehearsal is unlikely.

Abnormal Facial Emotion Recognition in Depression: Serial Testing in an Ultra-Rapid-Cycling Patient.

ERIC Educational Resources Information Center

George, Mark S.; Huggins, Teresa; McDermut, Wilson; Parekh, Priti I.; Rubinow, David; Post, Robert M.

1998-01-01

Mood disorder subjects have a selective deficit in recognizing human facial emotion. Whether the facial emotion recognition errors persist during normal mood states (i.e., are state vs. trait dependent) was studied in one male bipolar II patient. Results of five sessions are presented and discussed. (Author/EMK)

[Representation of letter position in visual word recognition process].

PubMed

Makioka, S

1994-08-01

Two experiments investigated the representation of letter position in visual word recognition process. In Experiment 1, subjects (12 undergraduates and graduates) were asked to detect a target word in a briefly-presented probe. Probes consisted of two kanji words. The latters which formed targets (critical letters) were always contained in probes. (e.g. target: [symbol: see text] probe: [symbol: see text]) High false alarm rate was observed when critical letters occupied the same within-word relative position (left or right within the word) in the probe words as in the target word. In Experiment 2 (subject were ten undergraduates and graduates), spaces adjacent to probe words were replaced by randomly chosen hiragana letters (e.g. [symbol: see text]), because spaces are not used to separate words in regular Japanese sentences. In addition to the effect of within-word relative position as in Experiment 1, the effect of between-word relative position (left or right across the probe words) was observed. These results suggest that information about within-word relative position of a letter is used in word recognition process. The effect of within-word relative position was explained by a connectionist model of word recognition.

MPAI (mass probes aided ionization) method for total analysis of biomolecules by mass spectrometry.

PubMed

Honda, Aki; Hayashi, Shinichiro; Hifumi, Hiroki; Honma, Yuya; Tanji, Noriyuki; Iwasawa, Naoko; Suzuki, Yoshio; Suzuki, Koji

2007-01-01

We have designed and synthesized various mass probes, which enable us to effectively ionize various molecules to be detected with mass spectrometry. We call the ionization method using mass probes the "MPAI (mass probes aided ionization)" method. We aim at the sensitive detection of various biological molecules, and also the detection of bio-molecules by a single mass spectrometry serially without changing the mechanical settings. Here, we review mass probes for small molecules with various functional groups and mass probes for proteins. Further, we introduce newly developed mass probes for proteins for highly sensitive detection.

Memory Asymmetry of Forward and Backward Associations in Recognition Tasks

ERIC Educational Resources Information Center

Yang, Jiongjiong; Zhao, Peng; Zhu, Zijian; Mecklinger, Axel; Fang, Zhiyong; Li, Han

2013-01-01

There is an intensive debate on whether memory for serial order is symmetric. The objective of this study was to explore whether associative asymmetry is modulated by memory task (recognition vs. cued recall). Participants were asked to memorize word triples (Experiments 1-2) or pairs (Experiments 3-6) during the study phase. They then recalled…

Face familiarity promotes stable identity recognition: exploring face perception using serial dependence

PubMed Central

Kok, Rebecca; Van der Burg, Erik; Rhodes, Gillian; Alais, David

2017-01-01

Studies suggest that familiar faces are processed in a manner distinct from unfamiliar faces and that familiarity with a face confers an advantage in identity recognition. Our visual system seems to capitalize on experience to build stable face representations that are impervious to variation in retinal input that may occur due to changes in lighting, viewpoint, viewing distance, eye movements, etc. Emerging evidence also suggests that our visual system maintains a continuous perception of a face's identity from one moment to the next despite the retinal input variations through serial dependence. This study investigates whether interactions occur between face familiarity and serial dependence. In two experiments, participants used a continuous scale to rate attractiveness of unfamiliar and familiar faces (either experimentally learned or famous) presented in rapid sequences. Both experiments revealed robust inter-trial effects in which attractiveness ratings for a given face depended on the preceding face's attractiveness. This inter-trial attractiveness effect was most pronounced for unfamiliar faces. Indeed, when participants were familiar with a given face, attractiveness ratings showed significantly less serial dependence. These results represent the first evidence that familiar faces can resist the temporal integration seen in sequential dependencies and highlight the importance of familiarity to visual cognition. PMID:28405355

Repetition priming of face recognition in a serial choice reaction-time task.

PubMed

Roberts, T; Bruce, V

1989-05-01

Marshall & Walker (1987) found that pictorial stimuli yield visual priming that is disrupted by an unpredictable visual event in the response-stimulus interval. They argue that visual stimuli are represented in memory in the form of distinct visual and object codes. Bruce & Young (1986) propose similar pictorial, structural and semantic codes which mediate the recognition of faces, yet repetition priming results obtained with faces as stimuli (Bruce & Valentine, 1985), and with objects (Warren & Morton, 1982) are quite different from those of Marshall & Walker (1987), in the sense that recognition is facilitated by pictures presented 20 minutes earlier. The experiment reported here used different views of familiar and unfamiliar faces as stimuli in a serial choice reaction-time task and found that, with identical pictures, repetition priming survives and intervening item requiring a response, with both familiar and unfamiliar faces. Furthermore, with familiar faces such priming was present even when the view of the prime was different from the target. The theoretical implications of these results are discussed.

Multi-scale Imaging of Cellular and Sub-cellular Structures using Scanning Probe Recognition Microscopy.

NASA Astrophysics Data System (ADS)

Chen, Q.; Rice, A. F.

2005-03-01

Scanning Probe Recognition Microscopy is a new scanning probe capability under development within our group to reliably return to and directly interact with a specific nanobiological feature of interest. In previous work, we have successfully recognized and classified tubular versus globular biological objects from experimental atomic force microscope images using a method based on normalized central moments [ref. 1]. In this paper we extend this work to include recognition schemes appropriate for cellular and sub-cellular structures. Globular cells containing tubular actin filaments are under investigation. Thus there are differences in external/internal shapes and scales. Continuous Wavelet Transform with a differential Gaussian mother wavelet is employed for multi- scale analysis. [ref. 1] Q. Chen, V. Ayres and L. Udpa, ``Biological Investigation Using Scanning Probe Recognition Microscopy,'' Proceedings 3rd IEEE Conference on Nanotechnology, vol. 2, p 863-865 (2003).

Working memory capacity and controlled serial memory search.

PubMed

Mızrak, Eda; Öztekin, Ilke

2016-08-01

The speed-accuracy trade-off (SAT) procedure was used to investigate the relationship between working memory capacity (WMC) and the dynamics of temporal order memory retrieval. High- and low-span participants (HSs, LSs) studied sequentially presented five-item lists, followed by two probes from the study list. Participants indicated the more recent probe. Overall, accuracy was higher for HSs compared to LSs. Crucially, in contrast to previous investigations that observed no impact of WMC on speed of access to item information in memory (e.g., Öztekin & McElree, 2010), recovery of temporal order memory was slower for LSs. While accessing an item's representation in memory can be direct, recovery of relational information such as temporal order information requires a more controlled serial memory search. Collectively, these data indicate that WMC effects are particularly prominent during high demands of cognitive control, such as serial search operations necessary to access temporal order information from memory. Copyright © 2016 Elsevier B.V. All rights reserved.

Identification of serial number on bank card using recurrent neural network

NASA Astrophysics Data System (ADS)

Liu, Li; Huang, Linlin; Xue, Jian

2018-04-01

Identification of serial number on bank card has many applications. Due to the different number printing mode, complex background, distortion in shape, etc., it is quite challenging to achieve high identification accuracy. In this paper, we propose a method using Normalization-Cooperated Gradient Feature (NCGF) and Recurrent Neural Network (RNN) based on Long Short-Term Memory (LSTM) for serial number identification. The NCGF maps the gradient direction elements of original image to direction planes such that the RNN with direction planes as input can recognize numbers more accurately. Taking the advantages of NCGF and RNN, we get 90%digit string recognition accuracy.

Mapping social behavior-induced brain activation at cellular resolution in the mouse

PubMed Central

Kim, Yongsoo; Venkataraju, Kannan Umadevi; Pradhan, Kith; Mende, Carolin; Taranda, Julian; Turaga, Srinivas C.; Arganda-Carreras, Ignacio; Ng, Lydia; Hawrylycz, Michael J.; Rockland, Kathleen; Seung, H. Sebastian; Osten, Pavel

2014-01-01

Understanding how brain activation mediates behaviors is a central goal of systems neuroscience. Here we apply an automated method for mapping brain activation in the mouse in order to probe how sex-specific social behaviors are represented in the male brain. Our method uses the immediate early gene c-fos, a marker of neuronal activation, visualized by serial two-photon tomography: the c-fos-GFP-positive neurons are computationally detected, their distribution is registered to a reference brain and a brain atlas, and their numbers are analyzed by statistical tests. Our results reveal distinct and shared female and male interaction-evoked patterns of male brain activation representing sex discrimination and social recognition. We also identify brain regions whose degree of activity correlates to specific features of social behaviors and estimate the total numbers and the densities of activated neurons per brain areas. Our study opens the door to automated screening of behavior-evoked brain activation in the mouse. PMID:25558063

An exemplar-familiarity model predicts short-term and long-term probe recognition across diverse forms of memory search.

PubMed

Nosofsky, Robert M; Cox, Gregory E; Cao, Rui; Shiffrin, Richard M

2014-11-01

Experiments were conducted to test a modern exemplar-familiarity model on its ability to account for both short-term and long-term probe recognition within the same memory-search paradigm. Also, making connections to the literature on attention and visual search, the model was used to interpret differences in probe-recognition performance across diverse conditions that manipulated relations between targets and foils across trials. Subjects saw lists of from 1 to 16 items followed by a single item recognition probe. In a varied-mapping condition, targets and foils could switch roles across trials; in a consistent-mapping condition, targets and foils never switched roles; and in an all-new condition, on each trial a completely new set of items formed the memory set. In the varied-mapping and all-new conditions, mean correct response times (RTs) and error proportions were curvilinear increasing functions of memory set size, with the RT results closely resembling ones from hybrid visual-memory search experiments reported by Wolfe (2012). In the consistent-mapping condition, new-probe RTs were invariant with set size, whereas old-probe RTs increased slightly with increasing study-test lag. With appropriate choice of psychologically interpretable free parameters, the model accounted well for the complete set of results. The work provides support for the hypothesis that a common set of processes involving exemplar-based familiarity may govern long-term and short-term probe recognition across wide varieties of memory- search conditions. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Multiple-scanning-probe tunneling microscope with nanoscale positional recognition function.

PubMed

Higuchi, Seiji; Kuramochi, Hiromi; Laurent, Olivier; Komatsubara, Takashi; Machida, Shinichi; Aono, Masakazu; Obori, Kenichi; Nakayama, Tomonobu

2010-07-01

Over the past decade, multiple-scanning-probe microscope systems with independently controlled probes have been developed for nanoscale electrical measurements. We developed a quadruple-scanning-probe tunneling microscope (QSPTM) that can determine and control the probe position through scanning-probe imaging. The difficulty of operating multiple probes with submicrometer precision drastically increases with the number of probes. To solve problems such as determining the relative positions of the probes and avoiding of contact between the probes, we adopted sample-scanning methods to obtain four images simultaneously and developed an original control system for QSPTM operation with a function of automatic positional recognition. These improvements make the QSPTM a more practical and useful instrument since four images can now be reliably produced, and consequently the positioning of the four probes becomes easier owing to the reduced chance of accidental contact between the probes.

Cognitive, emotional and social markers of serial murdering.

PubMed

Angrilli, Alessandro; Sartori, Giuseppe; Donzella, Giovanna

2013-01-01

Although criminal psychopathy is starting to be relatively well described, our knowledge of the characteristics and scientific markers of serial murdering is still very poor. A serial killer who murdered more than five people, KT, was administered a battery of standardized tests aimed at measuring neuropsychological impairment and social/emotional cognition deficits. KT exhibited a striking dissociation between a high level of emotional detachment and a low score on the antisocial behavior scale on the Psychopathy Checklist-Revised (PCL-R). The Minnesota Multiphasic Personality Inventory-2 showed a normal pattern with the psychotic triad at borderline level. KT had a high intelligence score and showed almost no impairment in cognitive tests sensitive to frontal lobe dysfunction (Wisconsin Card Sorting Test, Theory of Mind, Tower of London, this latter evidenced a mild impairment in planning performance). In the tests on moral, emotional and social cognition, his patterns of response differed from matched controls and from past reports on criminal psychopaths as, unlike these individuals, KT exhibited normal recognition of fear and a relatively intact knowledge of moral rules but he was impaired in the recognition of anger, embarrassment and conventional social rules. The overall picture of KT suggests that serial killing may be closer to normality than psychopathy defined according to either the DSM IV or the PCL-R, and it would be characterized by a relatively spared moral cognition and selective deficits in social and emotional cognition domains.

FY15 Status of Immersion Phased Array Ultrasonic Probe Development and Performance Demonstration Results for Under Sodium Viewing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diaz, Aaron A.; Larche, Michael R.; Mathews, Royce

2015-09-01

This Technical Letter Report (TLR) describes work conducted at the Pacific Northwest National Laboratory (PNNL) during FY 2015 on the under-sodium viewing (USV) PNNL project 58745, Work Package AT-15PN230102. This TLR satisfies PNNL’s M3AT-15PN2301027 milestone, and is focused on summarizing the design, development, and evaluation of a two-dimensional matrix phased-array probe referred to as serial number 3 (SN3). In addition, this TLR also provides the results from a performance demonstration of in-sodium target detection trials at 260°C using a one-dimensional 22-element linear array developed in FY14 and referred to as serial number 2 (SN2).

Modality independence of order coding in working memory: Evidence from cross-modal order interference at recall.

PubMed

Vandierendonck, André

2016-01-01

Working memory researchers do not agree on whether order in serial recall is encoded by dedicated modality-specific systems or by a more general modality-independent system. Although previous research supports the existence of autonomous modality-specific systems, it has been shown that serial recognition memory is prone to cross-modal order interference by concurrent tasks. The present study used a serial recall task, which was performed in a single-task condition and in a dual-task condition with an embedded memory task in the retention interval. The modality of the serial task was either verbal or visuospatial, and the embedded tasks were in the other modality and required either serial or item recall. Care was taken to avoid modality overlaps during presentation and recall. In Experiment 1, visuospatial but not verbal serial recall was more impaired when the embedded task was an order than when it was an item task. Using a more difficult verbal serial recall task, verbal serial recall was also more impaired by another order recall task in Experiment 2. These findings are consistent with the hypothesis of modality-independent order coding. The implications for views on short-term recall and the multicomponent view of working memory are discussed.

The Effects of Probe Similarity on Retrieval and Comparison Processes in Associative Recognition.

PubMed

Zhang, Qiong; Walsh, Matthew M; Anderson, John R

2017-02-01

In this study, we investigated the information processing stages underlying associative recognition. We recorded EEG data while participants performed a task that involved deciding whether a probe word triple matched any previously studied triple. We varied the similarity between probes and studied triples. According to a model of associative recognition developed in the Adaptive Control of Thought-Rational cognitive architecture, probe similarity affects the duration of the retrieval stage: Retrieval is fastest when the probe is similar to a studied triple. This effect may be obscured, however, by the duration of the comparison stage, which is fastest when the probe is not similar to the retrieved triple. Owing to the opposing effects of probe similarity on retrieval and comparison, overall RTs provide little information about each stage's duration. As such, we evaluated the model using a novel approach that decomposes the EEG signal into a sequence of latent states and provides information about the durations of the underlying information processing stages. The approach uses a hidden semi-Markov model to identify brief sinusoidal peaks (called bumps) that mark the onsets of distinct cognitive stages. The analysis confirmed that probe type has opposite effects on retrieval and comparison stages.

A model linking immediate serial recall, the Hebb repetition effect and the learning of phonological word forms

PubMed Central

Page, M. P. A.; Norris, D.

2009-01-01

We briefly review the considerable evidence for a common ordering mechanism underlying both immediate serial recall (ISR) tasks (e.g. digit span, non-word repetition) and the learning of phonological word forms. In addition, we discuss how recent work on the Hebb repetition effect is consistent with the idea that learning in this task is itself a laboratory analogue of the sequence-learning component of phonological word-form learning. In this light, we present a unifying modelling framework that seeks to account for ISR and Hebb repetition effects, while being extensible to word-form learning. Because word-form learning is performed in the service of later word recognition, our modelling framework also subsumes a mechanism for word recognition from continuous speech. Simulations of a computational implementation of the modelling framework are presented and are shown to be in accordance with data from the Hebb repetition paradigm. PMID:19933143

Binding and Inhibition in Working Memory: Individual and Age Differences in Short-Term Recognition

ERIC Educational Resources Information Center

Oberauer, Klaus

2005-01-01

Two studies investigated the relationship between working memory capacity (WMC), adult age, and the resolution of conflict between familiarity and recollection in short-term recognition tasks. Experiment 1 showed a specific deficit of young adults with low WMC in rejecting intrusion probes (i.e., highly familiar probes) in a modified Sternberg…

Encoding Speed, Rehearsal, and Probed Recall of Dyslexic Boys

ERIC Educational Resources Information Center

Spring, Carl; Capps, Carolyn

1974-01-01

The interaction of reading ability with serial position indicates that short-term storage is equally robust for dyslexics and normals but that long-term storage is impaired for dyslexics. (Author/BJG)

Activation and binding in verbal working memory: a dual-process model for the recognition of nonwords.

PubMed

Oberauer, Klaus; Lange, Elke B

2009-02-01

The article presents a mathematical model of short-term recognition based on dual-process models and the three-component theory of working memory [Oberauer, K. (2002). Access to information in working memory: Exploring the focus of attention. Journal of Experimental Psychology: Learning, Memory, and Cognition, 28, 411-421]. Familiarity arises from activated representations in long-term memory, ignoring their relations; recollection retrieves bindings in the capacity-limited component of working memory. In three experiments participants encoded two short lists of nonwords for immediate recognition, one of which was then cued as irrelevant. Probes from the irrelevant list were rejected more slowly than new probes; this was also found with probes recombining letters of irrelevant nonwords, suggesting that familiarity arises from individual letters independent of their relations. When asked to accept probes whose letters were all in the relevant list, regardless of their conjunction, participants accepted probes preserving the original conjunctions faster than recombinations, showing that recollection accessed feature bindings automatically. The model fit the data best when familiarity depended only on matching letters, whereas recollection used binding information.

When Does a Good Working Memory Counteract Proactive Interference? Surprising Evidence from a Probe Recognition Task

ERIC Educational Resources Information Center

Cowan, Nelson; Saults, J. Scott

2013-01-01

It is often proposed that individuals with high working memory span overcome proactive interference (PI) from previous trials, saving working memory for task-relevant items. We examined this hypothesis in word-list probe recognition. We found no difference in PI related to span. Instead, ex-Gaussian analysis of reaction time showed speed…

Chemical Probes of Rapid Estrogen Signaling in Breast Cancer Treatment and Chemoprevention

DTIC Science & Technology

2007-04-01

The analogs will also be conju- gated to cell-impermeable polyacrylate polymers that should allow for selective targeting of membrane-initiated...the GW7604 analogs. Briefly, serial dilutions of the different compounds were prepared in ES2 screening buffer (100 mM potassium phosphate, pH7.4, 100...AD_________________ Award Number: W81XWH-04-1-0447 TITLE: CHEMICAL PROBES OF RAPID ESTROGEN

Non-contact data access with direction identification for industrial differential serial bus

NASA Astrophysics Data System (ADS)

Xie, Kai; Li, Xiaoping; Zhang, Hanlu; Yang, Ming; Ye, Yinghao

2013-06-01

We propose a non-contact method for accessing data in industrial differential serial bus applications, which could serve as an effective and safe online testing and diagnosing tool. The data stream and the transmission direction are reconstructed simultaneously from the near-field emanations of a twisted pair, eliminating direct contact with the actual conductors, and avoiding damage to the insulation (only the outer sheathing is removed). A non-contact probe with the ability to sense electric and magnetic fields is presented, as are theories for data reconstruction, direction identification, and a circuit implementation. The prototype was built using inexpensive components and then tested on a standard RS-485 industrial serial bus. Experimental results verified the validity of the proposed scheme.

Ease of Access to List Items in Short-Term Memory Depends on the Order of the Recognition Probes

ERIC Educational Resources Information Center

Lange, Elke B.; Cerella, John; Verhaeghen, Paul

2011-01-01

We report data from 4 experiments using a recognition design with multiple probes to be matched to specific study positions. Items could be accessed rapidly, independent of set size, when the test order matched the study order (forward condition). When the order of testing was random, backward, or in a prelearned irregular sequence (reordered…

A Series of Fluorescent and Colorimetric Chemodosimeters for Selective Recognition of Cyanide Based on the FRET Mechanism.

PubMed

Hua, Ying-Xi; Shao, Yongliang; Wang, Ya-Wen; Peng, Yu

2017-06-16

A series of fluorescence "turn-on" probes (PY, AN, NA, B1, and B2) have been developed and successfully applied to detect cyanide anions based on the Michael addition reaction and FRET mechanism. These probes demonstrated good selectivity, high sensitivity, and very fast recognition for CN - . In particular, the fluorescence response of probe NA finished within 3 s. Low limits of detection (down to 63 nM) are also obtained in these probes with remarkable fluorescence enhancement factors. In addition, fluorescence colors of these probes turned to blue, yellow, or orange upon sensing CN - . In UV-vis mode, all of them showed ratiometric response for CN - . 1 H NMR titration experiments and TDDFT calculations were taken to verify the mechanism of the specific reaction and fluorescence properties of the corresponding compounds. Moreover, silica gel plates with these probes were also fabricated and utilized to detect cyanide.

Redox polymer and probe DNA tethered to gold electrodes for enzyme-amplified amperometric detection of DNA hybridization.

PubMed

Kavanagh, Paul; Leech, Dónal

2006-04-15

The detection of nucleic acids based upon recognition surfaces formed by co-immobilization of a redox polymer mediator and DNA probe sequences on gold electrodes is described. The recognition surface consists of a redox polymer, [Os(2,2'-bipyridine)2(polyvinylimidazole)(10)Cl](+/2+), and a model single DNA strand cross-linked and tethered to a gold electrode via an anchoring self-assembled monolayer (SAM) of cysteamine. Hybridization between the immobilized probe DNA of the recognition surface and a biotin-conjugated target DNA sequence (designed from the ssrA gene of Listeria monocytogenes), followed by addition of an enzyme (glucose oxidase)-avidin conjugate, results in electrical contact between the enzyme and the mediating redox polymer. In the presence of glucose, the current generated due to the catalytic oxidation of glucose to gluconolactone is measured, and a response is obtained that is binding-dependent. The tethering of the probe DNA and redox polymer to the SAM improves the stability of the surface to assay conditions of rigorous washing and high salt concentration (1 M). These conditions eliminate nonspecific interaction of both the target DNA and the enzyme-avidin conjugate with the recognition surfaces. The sensor response increases linearly with increasing concentration of target DNA in the range of 1 x 10(-9) to 2 x 10(-6) M. The detection limit is approximately 1.4 fmol, (corresponding to 0.2 nM of target DNA). Regeneration of the recognition surface is possible by treatment with 0.25 M NaOH solution. After rehybridization of the regenerated surface with the target DNA sequence, >95% of the current is recovered, indicating that the redox polymer and probe DNA are strongly bound to the surface. These results demonstrate the utility of the proposed approach.

Determination of Cardiac Output and Ejection Fraction with the Dual Cardiac Probe

PubMed Central

Cardenas, Carlos G.; Depuey, E. Gordon; Thompson, Wayne L.; Garcia, Efrain; Burdine, John A.

1983-01-01

Cardiac output and left ventricular ejection fraction were determined noninvasively at the bedside in 26 patients by using a dual scintillation probe. The probe is a nonimaging detector that records a high frequency time-activity curve of the passage of an intravenously injected radioactive bolus through the heart. Results were correlated with ejection fraction measured by biplane cineangiography (r = 0.80) and cardiac output determined by green dye dilution (R = 0.86). It is concluded that the dual probe provides an accurate noninvasive means of measuring these parameters, and that it may be particularly applicable to serial measurements in patients in the intensive care unit. Images PMID:15227151

A protocol for preparing, characterizing and using three RNA-specific, live cell imaging probes: E36, E144 and F22.

PubMed

Li, Qian; Chang, Young-Tae

2006-01-01

This protocol outlines a methodology for the preparation and characterization of three RNA-specific fluorescent probes (E36, E144 and F22) and their use in live cell imaging. It describes a detailed procedure for their chemical synthesis and purification; serial product characterization and quality control tests, including measurements of their fluorescence properties in solution, measurement of RNA specificity and analysis of cellular toxicity; and live cell staining and counterstaining with Hoechst or DAPI. Preparation and application of these RNA imaging probes takes 1 week.

Schizophrenia patients demonstrate a dissociation on declarative and non-declarative memory tests.

PubMed

Perry, W; Light, G A; Davis, H; Braff, D L

2000-12-15

Declarative memory refers to the recall and recognition of factual information. In contrast, non-declarative memory entails a facilitation of memory based on prior exposure and is typically assessed with priming and perceptual-motor sequencing tasks. In this study, schizophrenia patients were compared to normal comparison subjects on two computerized memory tasks: the Word-stem Priming Test (n=30) and the Pattern Sequence Learning Test (n=20). Word-stem Priming includes recall, recognition (declarative) and priming (non-declarative) components of memory. The schizophrenia patients demonstrated an impaired performance on recall of words with relative improvement during the recognition portion of the test. Furthermore, they performed normally on the priming portion of the test. Thus, on tests of declarative memory, the patients had retrieval deficits with intact performance on the non-declarative memory component. The Pattern Sequence Learning Test utilizes a serial reaction time paradigm to assess non-declarative memory. The schizophrenia patients' serial reaction time was significantly slower than that of comparison subjects. However, the patients' rate of acquisition was not different from the normal comparison group. The data suggest that patients with schizophrenia process more slowly than normal, but have an intact non-declarative memory. The schizophrenia patients' dissociation on declarative vs. non-declarative memory tests is discussed in terms of possible underlying structural impairment.

Concreteness effects in short-term memory: a test of the item-order hypothesis.

PubMed

Roche, Jaclynn; Tolan, G Anne; Tehan, Gerald

2011-12-01

The following experiments explore word length and concreteness effects in short-term memory within an item-order processing framework. This framework asserts order memory is better for those items that are relatively easy to process at the item level. However, words that are difficult to process benefit at the item level for increased attention/resources being applied. The prediction of the model is that differential item and order processing can be detected in episodic tasks that differ in the degree to which item or order memory are required by the task. The item-order account has been applied to the word length effect such that there is a short word advantage in serial recall but a long word advantage in item recognition. The current experiment considered the possibility that concreteness effects might be explained within the same framework. In two experiments, word length (Experiment 1) and concreteness (Experiment 2) are examined using forward serial recall, backward serial recall, and item recognition. These results for word length replicate previous studies showing the dissociation in item and order tasks. The same was not true for the concreteness effect. In all three tasks concrete words were better remembered than abstract words. The concreteness effect cannot be explained in terms of an item-order trade off. PsycINFO Database Record (c) 2011 APA, all rights reserved.

Temporal precision and the capacity of auditory-verbal short-term memory.

PubMed

Gilbert, Rebecca A; Hitch, Graham J; Hartley, Tom

2017-12-01

The capacity of serially ordered auditory-verbal short-term memory (AVSTM) is sensitive to the timing of the material to be stored, and both temporal processing and AVSTM capacity are implicated in the development of language. We developed a novel "rehearsal-probe" task to investigate the relationship between temporal precision and the capacity to remember serial order. Participants listened to a sub-span sequence of spoken digits and silently rehearsed the items and their timing during an unfilled retention interval. After an unpredictable delay, a tone prompted report of the item being rehearsed at that moment. An initial experiment showed cyclic distributions of item responses over time, with peaks preserving serial order and broad, overlapping tails. The spread of the response distributions increased with additional memory load and correlated negatively with participants' auditory digit spans. A second study replicated the negative correlation and demonstrated its specificity to AVSTM by controlling for differences in visuo-spatial STM and nonverbal IQ. The results are consistent with the idea that a common resource underpins both the temporal precision and capacity of AVSTM. The rehearsal-probe task may provide a valuable tool for investigating links between temporal processing and AVSTM capacity in the context of speech and language abilities.

Impact of auditory selective attention on verbal short-term memory and vocabulary development.

PubMed

Majerus, Steve; Heiligenstein, Lucie; Gautherot, Nathalie; Poncelet, Martine; Van der Linden, Martial

2009-05-01

This study investigated the role of auditory selective attention capacities as a possible mediator of the well-established association between verbal short-term memory (STM) and vocabulary development. A total of 47 6- and 7-year-olds were administered verbal immediate serial recall and auditory attention tasks. Both task types probed processing of item and serial order information because recent studies have shown this distinction to be critical when exploring relations between STM and lexical development. Multiple regression and variance partitioning analyses highlighted two variables as determinants of vocabulary development: (a) a serial order processing variable shared by STM order recall and a selective attention task for sequence information and (b) an attentional variable shared by selective attention measures targeting item or sequence information. The current study highlights the need for integrative STM models, accounting for conjoined influences of attentional capacities and serial order processing capacities on STM performance and the establishment of the lexical language network.

Asymmetric Cationic Porphyrin as a New G-Quadruplex Probe with Wash-Free Cancer-Targeted Imaging Ability Under Acidic Microenvironments.

PubMed

Zhang, Ran; Cheng, Meng; Zhang, Li-Ming; Zhu, Li-Na; Kong, De-Ming

2018-04-25

Porphyrins are promising candidates for nucleic acid G-quadruplex-specific optical recognition. We previously demonstrated that G-quadruplex recognition specificity of porphyrins could be improved by introducing bulky side arm substituents, but the enhanced protonation tendency limits their applications in some cases, such as under acidic conditions. Here, we demonstrated that the protonation tendency of porphyrin derivatives could be efficiently overcome by increasing molecular asymmetry. To validate this, an asymmetric, water-soluble, cationic porphyrin FA-TMPipEOPP (5-{4-[2-[[(2 E)-3-[3-methoxy-4-[2-(1-methyl-1-piperidinyl)ethoxy]phenyl]-1-oxo-2-propenyl]oxy]ethoxy]phenyl},10,15,20-tri{4-[2-(1-methyl-1-piperidinyl)ethoxy]-phenyl}porphyrin) was synthesized by introducing a ferulic acid (FA) unit at one side arm, and its structure was well-characterized. Unlike its symmetric counterpart TMPipEOPP that has a tendency to protonate under acidic conditions, FA-TMPipEOPP remained in the unprotonated monomeric form under the pH range of 2.0-8.0. Correspondingly, FA-TMPipEOPP showed better G-quadruplex recognition specificity than TMPipEOPP and thus might be used as a specific optical probe for colorimetric and fluorescent recognition of G-quadruplexes under acidic conditions. The feasibility was demonstrated by two proof-of-concept studies: probing structural competition between G-quadruplexes and duplexes and label-free and wash-free cancer cell-targeted bioimaging under an acidic tumor microenvironment. As G-quadruplex optical probes, FA-TMPipEOPP works well under acidic conditions, whereas TMPipEOPP works well under neutral conditions. This finding provides useful information for G-quadruplex probe research. That is, porphyrin-based G-quadruplex probes suitable for different pH conditions might be obtained by adjusting the molecular symmetry.

Recognition Time for Letters and Nonletters: Effects of Serial Position, Array Size, and Processing Order.

ERIC Educational Resources Information Center

Mason, Mildred

1982-01-01

Three experiments report additional evidence that it is a mistake to account for all interletter effects solely in terms of sensory variables. These experiments attest to the importance of structural variables such as retina location, array size, and ordinal position. (Author/PN)

Iconic gestures prime related concepts: an ERP study.

PubMed

Wu, Ying Croon; Coulson, Seana

2007-02-01

To assess priming by iconic gestures, we recorded EEG (at 29 scalp sites) in two experiments while adults watched short, soundless videos of spontaneously produced, cospeech iconic gestures followed by related or unrelated probe words. In Experiment 1, participants classified the relatedness between gestures and words. In Experiment 2, they attended to stimuli, and performed an incidental recognition memory test on words presented during the EEG recording session. Event-related potentials (ERPs) time-locked to the onset of probe words were measured, along with response latencies and word recognition rates. Although word relatedness did not affect reaction times or recognition rates, contextually related probe words elicited less-negative ERPs than did unrelated ones between 300 and 500 msec after stimulus onset (N400) in both experiments. These findings demonstrate sensitivity to semantic relations between iconic gestures and words in brain activity engendered during word comprehension.

An uracil-linked hydroxyflavone probe for the recognition of ATP

PubMed Central

Bojtár, Márton; Janzsó-Berend, Péter Zoltán; Mester, Dávid; Hessz, Dóra; Kállay, Mihály; Kubinyi, Miklós

2018-01-01

Background: Nucleotides are essential molecules in living systems due to their paramount importance in various physiological processes. In the past years, numerous attempts were made to selectively recognize and detect these analytes, especially ATP using small-molecule fluorescent chemosensors. Despite the various solutions, the selective detection of ATP is still challenging due to the structural similarity of various nucleotides. In this paper, we report the conjugation of a uracil nucleobase to the known 4’-dimethylamino-hydroxyflavone fluorophore. Results: The complexation of this scaffold with ATP is already known. The complex is held together by stacking and electrostatic interactions. To achieve multi-point recognition, we designed the uracil-appended version of this probe to include complementary base-pairing interactions. The theoretical calculations revealed the availability of multiple complex structures. The synthesis was performed using click chemistry and the nucleotide recognition properties of the probe were evaluated using fluorescence spectroscopy. Conclusions: The first, uracil-containing fluorescent ATP probe based on a hydroxyflavone fluorophore was synthesized and evaluated. A selective complexation with ATP was observed and a ratiometric response in the excitation spectrum. PMID:29719572

Discovery of a novel calcium-sensitive fluorescent probe for α-ketoglutarate.

PubMed

Gan, Lin-Lin; Chen, Lin-Hai; Nan, Fa-Jun

2017-12-01

α-Ketoglutarate (α-KG), a pivotal metabolite in energy metabolism, has been implicated in nonalcoholic fatty liver disease (NAFLD) and several cancers. It is recently proposed that plasma α-KG is a surrogate biomarker of NAFLD. Here, we report the development of a novel "turn-on" chemosensor for α-KG that contains a coumarin moiety as a fluorophore. Using benzothiazole-coumarin (BTC) as inspiration, we designed a probe for calcium ion recognition that possesses a unique fluorophore compared with previously reported probes for α-KG measurement. This chemosensor is based on the specific Schiff base reaction and the calcium ion recognition property of the widely used calcium indicator BTC. The probe was synthesized, and a series of parallel experiments were conducted to optimize the chemical recognition process. Compared to the initial weak fluorescence, a remarkable 7.6-fold enhancement in fluorescence intensity (I/I 0 at 495 nm) was observed for the conditions in which the probe (1 μmol/L), α-KG (50 μmol/L), and Ca 2+ (100 μmol/L) were incubated at 30 °C in EtOH. The probe displayed good selectivity for α-KG even in an environment with an abundance of amino acids and other interfering species such as glutaric acid. We determined that the quantitative detection range of α-KG in EtOH was between 5 and 50 μmol/L. Finally, probe in serum loaded with α-KG (10 mmol/L) showed a 7.4-fold fluorescence enhancement. In summary, a novel probe for detecting the biomarker α-KG through a typical Schiff base reaction has been discovered. With further optimization, this probe may be a good alternative for detecting the physiological metabolite α-KG.

Recognition- and reactivity-based fluorescent probes for studying transition metal signaling in living systems.

PubMed

Aron, Allegra T; Ramos-Torres, Karla M; Cotruvo, Joseph A; Chang, Christopher J

2015-08-18

Metals are essential for life, playing critical roles in all aspects of the central dogma of biology (e.g., the transcription and translation of nucleic acids and synthesis of proteins). Redox-inactive alkali, alkaline earth, and transition metals such as sodium, potassium, calcium, and zinc are widely recognized as dynamic signals, whereas redox-active transition metals such as copper and iron are traditionally thought of as sequestered by protein ligands, including as static enzyme cofactors, in part because of their potential to trigger oxidative stress and damage via Fenton chemistry. Metals in biology can be broadly categorized into two pools: static and labile. In the former, proteins and other macromolecules tightly bind metals; in the latter, metals are bound relatively weakly to cellular ligands, including proteins and low molecular weight ligands. Fluorescent probes can be useful tools for studying the roles of transition metals in their labile forms. Probes for imaging transition metal dynamics in living systems must meet several stringent criteria. In addition to exhibiting desirable photophysical properties and biocompatibility, they must be selective and show a fluorescence turn-on response to the metal of interest. To meet this challenge, we have pursued two general strategies for metal detection, termed "recognition" and "reactivity". Our design of transition metal probes makes use of a recognition-based approach for copper and nickel and a reactivity-based approach for cobalt and iron. This Account summarizes progress in our laboratory on both the development and application of fluorescent probes to identify and study the signaling roles of transition metals in biology. In conjunction with complementary methods for direct metal detection and genetic and/or pharmacological manipulations, fluorescent probes for transition metals have helped reveal a number of principles underlying transition metal dynamics. In this Account, we give three recent examples from our laboratory and collaborations in which applications of chemical probes reveal that labile copper contributes to various physiologies. The first example shows that copper is an endogenous regulator of neuronal activity, the second illustrates cellular prioritization of mitochondrial copper homeostasis, and the third identifies the "cuprosome" as a new copper storage compartment in Chlamydomonas reinhardtii green algae. Indeed, recognition- and reactivity-based fluorescent probes have helped to uncover new biological roles for labile transition metals, and the further development of fluorescent probes, including ones with varied Kd values and new reaction triggers and recognition receptors, will continue to reveal exciting and new biological roles for labile transition metals.

Sensitive fluorescence on-off probes for the fast detection of a chemical warfare agent mimic.

PubMed

Khan, Muhammad Shar Jhahan; Wang, Ya-Wen; Senge, Mathias O; Peng, Yu

2018-01-15

Two highly sensitive probes bearing a nucleophilic imine moiety have been utilized for the selective detection of chemical warfare agent (CWA) mimics. Diethyl chlorophosphate (DCP) was used as mimic CWAs. Both iminocoumarin-benzothiazole-based probes not only demonstrated a remarkable fluorescence ON-OFF response and good recognition, but also exhibited fast response times (10s) along with color changes upon addition of DCP. Limits of detection for the two sensors 1 and 2 were calculated as 0.065μM and 0.21μM, respectively, which are much lower than most other reported probes. These two probes not only show high sensitivity and selectivity in solution, but can also be applied for the recognition of DCP in the gas state, with significant color changes easily observed by the naked eye. Copyright © 2017 Elsevier B.V. All rights reserved.

Superior serial memory in the blind: a case of cognitive compensatory adjustment.

PubMed

Raz, Noa; Striem, Ella; Pundak, Golan; Orlov, Tanya; Zohary, Ehud

2007-07-03

In the absence of vision, perception of space is likely to be highly dependent on memory. As previously stated, the blind tend to code spatial information in the form of "route-like" sequential representations [1-3]. Thus, serial memory, indicating the order in which items are encountered, may be especially important for the blind to generate a mental picture of the world. In accordance, we find that the congenitally blind are remarkably superior to sighted peers in serial memory tasks. Specifically, subjects heard a list of 20 words and were instructed to recall the words according to their original order in the list. The blind recalled more words than the sighted (indicating better item memory), but their greatest advantage was in recalling longer word sequences (according to their original order). We further show that the serial memory superiority of the blind is not merely a result of their advantage in item recall per se (as we additionally confirm via a separate recognition memory task). These results suggest the refinement of a specific cognitive ability to compensate for blindness in humans.

Recognition memory probes affect what is remembered in schizophrenia.

PubMed

Schwartz, Barbara L; Parker, Elizabeth S; Rosse, Richard B; Deutsch, Stephen I

2009-05-15

Cognitive psychology offers tools to localize the memory processes most vulnerable to disruption in schizophrenia and to identify how patients with schizophrenia best remember. In this research, we used the University of Southern California Repeatable Episodic Memory Test (USC-REMT; Parker, E.S., Landau, S.M., Whipple, S.C., Schwartz, B.L., 2004. Aging, recall, and recognition: A study on the sensitivity of the University of Southern California Repeatable Episodic Memory Test (USC-REMT). Journal of Clinical and Experimental Neuropsychology 26(3), 428-440.) to examine how two different recognition memory probes affect memory performance in patients with schizophrenia and matched controls. Patients with schizophrenia studied equivalent word lists and were tested by yes-no recognition and forced-choice recognition following identical encoding and storage conditions. Compared with controls, patients with schizophrenia were particularly impaired when tested by yes-no recognition relative to forced-choice recognition. Patients had greatest deficits on hits in yes-no recognition but did not exhibit elevated false alarms. The data point to the importance of retrieval processes in schizophrenia, and highlight the need for further research on ways to help patients with schizophrenia access what they have learned.

Electrophysiological correlates of proactive interference in the 'Recent Probes' verbal working memory task.

PubMed

Zhang, John X; Wu, Renhua; Kong, Lingyue; Weng, Xuchu; Du, Yingchun

2010-06-01

Using event-related potentials (ERPs), the present study examined the temporal dynamics of proactive interference in working memory using a recent probes task. Participants memorized and retained a target set of four letters over a short retention interval. They then responded to a recognition probe by judging whether it was from the memory set. ERP waveforms elicited by positive probes compared to those from negative probes showed positive shifts in a fronto-central early N2 component and a parietal late positive component (LPC). The LPC was identified as the electrophysiological signature of proactive interference, as it differentiated between two types of negative probes defined based on whether they were recently encountered. These results indicate that the proactive interference we observed arises from a mismatch between familiarity and contextual information during recognition memory. When considered together with related studies in the literature, the results also suggest that there are different forms of proactive interference associated with different neural correlates. Copyright 2010 Elsevier Ltd. All rights reserved.

Applications of the Ultrasonic Serial Number Restoration Technique to Guns and Typical Stolen Articles

NASA Technical Reports Server (NTRS)

Young, S. G.

1976-01-01

An ultrasonic cavitation method for restoring obliterated serial numbers has been further explored by application to articles involved in police cases. The method was applied successfully to gun parts. In one case portions of numbers were restored after prior failure by other laboratories using chemical etching techniques. The ultrasonic method was not successful on a heavily obliterated and restamped automobile engine block, but it was partially successful on a motorcycle gear-case housing. Additional studies were made on the effect of a larger diameter ultrasonic probe, and on the method's ability to restore numbers obliterated by peening.

fMRI characterization of visual working memory recognition.

PubMed

Rahm, Benjamin; Kaiser, Jochen; Unterrainer, Josef M; Simon, Juliane; Bledowski, Christoph

2014-04-15

Encoding and maintenance of information in visual working memory have been extensively studied, highlighting the crucial and capacity-limiting role of fronto-parietal regions. In contrast, the neural basis of recognition in visual working memory has remained largely unspecified. Cognitive models suggest that recognition relies on a matching process that compares sensory information with the mental representations held in memory. To characterize the neural basis of recognition we varied both the need for recognition and the degree of similarity between the probe item and the memory contents, while independently manipulating memory load to produce load-related fronto-parietal activations. fMRI revealed a fractionation of working memory functions across four distributed networks. First, fronto-parietal regions were activated independent of the need for recognition. Second, anterior parts of load-related parietal regions contributed to recognition but their activations were independent of the difficulty of matching in terms of sample-probe similarity. These results argue against a key role of the fronto-parietal attention network in recognition. Rather the third group of regions including bilateral temporo-parietal junction, posterior cingulate cortex and superior frontal sulcus reflected demands on matching both in terms of sample-probe-similarity and the number of items to be compared. Also, fourth, bilateral motor regions and right superior parietal cortex showed higher activation when matching provided clear evidence for a decision. Together, the segregation between the well-known fronto-parietal activations attributed to attentional operations in working memory from those regions involved in matching supports the theoretical view of separable attentional and mnemonic contributions to working memory. Yet, the close theoretical and empirical correspondence to perceptual decision making may call for an explicit consideration of decision making mechanisms in conceptions of working memory. Copyright © 2013 Elsevier Inc. All rights reserved.

Hyaluronan functionalizing QDs as turn-on fluorescent probe for targeted recognition CD44 receptor

NASA Astrophysics Data System (ADS)

Zhou, Shang; Huo, Danqun; Hou, Changjun; Yang, Mei; Fa, Huanbao

2017-09-01

The recognition of tumor markers in living cancer cells has attracted increasing interest. In the present study, the turn-on fluorescence probe was designed based on the fluorescence of thiolated chitosan-coated CdTe QDs (CdTe/TCS QDs) quenched by hyaluronan, which could provide the low background signal for sensitive cellular imaging. This system is expected to offer specific recognition of CD44 receptor over other substances owing to the specific affinity of hyaluronan and CD44 receptor ( 8-9 kcal/mol). The probe is stable in aqueous and has little toxicity to living cells; thus, it can be utilized for targeted cancer cell imaging. The living lung cancer cell imaging experiments further demonstrate its value in recognizing cell-surface CD44 receptor with turn-on mode. In addition, the probe can be used to recognize and differentiate the subtypes of lung cancer cells based on the difference of CD44 expression on the surface of lung cancer cells. And, the western blot test further confirmed that the expression level of the CD44 receptor in lung cancer cells is different. Therefore, this probe may be potentially applied in recognizing lung cancer cells with higher contrast and sensitivity and provide new tools for cancer prognosis and therapy. [Figure not available: see fulltext.

Fluorogenic PNA probes

PubMed Central

2018-01-01

Fluorogenic oligonucleotide probes that can produce a change in fluorescence signal upon binding to specific biomolecular targets, including nucleic acids as well as non-nucleic acid targets, such as proteins and small molecules, have applications in various important areas. These include diagnostics, drug development and as tools for studying biomolecular interactions in situ and in real time. The probes usually consist of a labeled oligonucleotide strand as a recognition element together with a mechanism for signal transduction that can translate the binding event into a measurable signal. While a number of strategies have been developed for the signal transduction, relatively little attention has been paid to the recognition element. Peptide nucleic acids (PNA) are DNA mimics with several favorable properties making them a potential alternative to natural nucleic acids for the development of fluorogenic probes, including their very strong and specific recognition and excellent chemical and biological stabilities in addition to their ability to bind to structured nucleic acid targets. In addition, the uncharged backbone of PNA allows for other unique designs that cannot be performed with oligonucleotides or analogues with negatively-charged backbones. This review aims to introduce the principle, showcase state-of-the-art technologies and update recent developments in the areas of fluorogenic PNA probes during the past 20 years. PMID:29507634

A split recognition mode combined with cascade signal amplification strategy for highly specific, sensitive detection of microRNA.

PubMed

Wang, Rui; Wang, Lei; Zhao, Haiyan; Jiang, Wei

2016-12-15

MicroRNAs (miRNAs) are vital for many biological processes and have been regarded as cancer biomarkers. Specific and sensitive detection of miRNAs is essential for cancer diagnosis and therapy. Herein, a split recognition mode combined with cascade signal amplification strategy is developed for highly specific and sensitive detection of miRNA. The split recognition mode possesses two specific recognition processes, which are based on toehold-mediated strand displacement reaction (TSDR) and direct hybridization reaction. Two recognition probes, hairpin probe (HP) with overhanging toehold domain and assistant probe (AP), are specially designed. Firstly, the toehold domain of HP and AP recognize part of miRNA simultaneously, accompanied with TSDR to unfold the HP and form the stable DNA Y-shaped junction structure (YJS). Then, the AP in YJS can further act as primer to initiate strand displacement amplification, releasing numerous trigger sequences. Finally, the trigger sequences hybridize with padlock DNA to initiate circular rolling circle amplification and generate enhanced fluorescence responses. In this strategy, the dual recognition effect of split recognition mode guarantees the excellent selectivity to discriminate let-7b from high-homology sequences. Furthermore, the high amplification efficiency of cascade signal amplification guarantees a high sensitivity with the detection limit of 3.2 pM and the concentration of let-7b in total RNA sample extracted from Hela cells is determined. These results indicate our strategy will be a promising miRNA detection strategy in clinical diagnosis and disease treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

A solvent-dependent fluorescent detection method for Fe(3+) and Hg(2+) based on a rhodamine B derivative.

PubMed

Li, Xutian; Yin, Yue; Deng, Junjie; Zhong, Huixian; Tang, Jian; Chen, Zhi; Yang, Liting; Ma, Li-Jun

2016-07-01

A new rhodamine B-benzofurazan based fluorescent probe (1) for Fe(3+) and Hg(2+) was synthesized. In aqueous solution containing 30% (v/v) ethanol, probe 1 shows a high selective fluorescent enhancement recognition to Fe(3+) with a binding ratio of 1:1 (probe 1: Fe(3+)), when the concentration of Fe(3+) is less than that of the probe. When the concentration of Fe(3+) is higher than that of the probe, it shows fluorescent "turn-on" response to Fe(3+) by opening the rhodamine spirolactam with a binding ratio of 1:2 (probe 1: Fe(3+)). Furthermore, probe 1 displays a high selectivity and a hypersensitivity (detection limit is 4.4nM) to Hg(2+) with a binding ratio of 1:1 in ethanol. NMR and UV-vis experiments indicate that the different fluorescent recognition signals to Fe(3+) and Hg(2+) are derived from different binding modes of 1-Fe(3+) and 1-Hg(2+). Copyright © 2016 Elsevier B.V. All rights reserved.

Lipidic cubic phase injector is a viable crystal delivery system for time-resolved serial crystallography

DOE PAGES

Nogly, Przemyslaw; Panneels, Valerie; Nelson, Garrett; ...

2016-08-22

Serial femtosecond crystallography (SFX) using X-ray free-electron laser sources is an emerging method with considerable potential for time-resolved pump-probe experiments. Here we present a lipidic cubic phase SFX structure of the light-driven proton pump bacteriorhodopsin (bR) to 2.3 Å resolution and a method to investigate protein dynamics with modest sample requirement. Time-resolved SFX (TR-SFX) with a pump-probe delay of 1 ms yields difference Fourier maps compatible with the dark to M state transition of bR. Importantly, the method is very sample efficient and reduces sample consumption to about 1 mg per collected time point. Accumulation of M intermediate within themore » crystal lattice is confirmed by time-resolved visible absorption spectroscopy. Furthermore, this study provides an important step towards characterizing the complete photocycle dynamics of retinal proteins and demonstrates the feasibility of a sample efficient viscous medium jet for TR-SFX.« less

Lipidic cubic phase injector is a viable crystal delivery system for time-resolved serial crystallography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nogly, Przemyslaw; Panneels, Valerie; Nelson, Garrett

Serial femtosecond crystallography (SFX) using X-ray free-electron laser sources is an emerging method with considerable potential for time-resolved pump-probe experiments. Here we present a lipidic cubic phase SFX structure of the light-driven proton pump bacteriorhodopsin (bR) to 2.3 Å resolution and a method to investigate protein dynamics with modest sample requirement. Time-resolved SFX (TR-SFX) with a pump-probe delay of 1 ms yields difference Fourier maps compatible with the dark to M state transition of bR. Importantly, the method is very sample efficient and reduces sample consumption to about 1 mg per collected time point. Accumulation of M intermediate within themore » crystal lattice is confirmed by time-resolved visible absorption spectroscopy. Furthermore, this study provides an important step towards characterizing the complete photocycle dynamics of retinal proteins and demonstrates the feasibility of a sample efficient viscous medium jet for TR-SFX.« less

Lipidic cubic phase injector is a viable crystal delivery system for time-resolved serial crystallography

PubMed Central

Nogly, Przemyslaw; Panneels, Valerie; Nelson, Garrett; Gati, Cornelius; Kimura, Tetsunari; Milne, Christopher; Milathianaki, Despina; Kubo, Minoru; Wu, Wenting; Conrad, Chelsie; Coe, Jesse; Bean, Richard; Zhao, Yun; Båth, Petra; Dods, Robert; Harimoorthy, Rajiv; Beyerlein, Kenneth R.; Rheinberger, Jan; James, Daniel; DePonte, Daniel; Li, Chufeng; Sala, Leonardo; Williams, Garth J.; Hunter, Mark S.; Koglin, Jason E.; Berntsen, Peter; Nango, Eriko; Iwata, So; Chapman, Henry N.; Fromme, Petra; Frank, Matthias; Abela, Rafael; Boutet, Sébastien; Barty, Anton; White, Thomas A.; Weierstall, Uwe; Spence, John; Neutze, Richard; Schertler, Gebhard; Standfuss, Jörg

2016-01-01

Serial femtosecond crystallography (SFX) using X-ray free-electron laser sources is an emerging method with considerable potential for time-resolved pump-probe experiments. Here we present a lipidic cubic phase SFX structure of the light-driven proton pump bacteriorhodopsin (bR) to 2.3 Å resolution and a method to investigate protein dynamics with modest sample requirement. Time-resolved SFX (TR-SFX) with a pump-probe delay of 1 ms yields difference Fourier maps compatible with the dark to M state transition of bR. Importantly, the method is very sample efficient and reduces sample consumption to about 1 mg per collected time point. Accumulation of M intermediate within the crystal lattice is confirmed by time-resolved visible absorption spectroscopy. This study provides an important step towards characterizing the complete photocycle dynamics of retinal proteins and demonstrates the feasibility of a sample efficient viscous medium jet for TR-SFX. PMID:27545823

Spoken Word Recognition and Serial Recall of Words from Components in the Phonological Network

ERIC Educational Resources Information Center

Siew, Cynthia S. Q.; Vitevitch, Michael S.

2016-01-01

Network science uses mathematical techniques to study complex systems such as the phonological lexicon (Vitevitch, 2008). The phonological network consists of a "giant component" (the largest connected component of the network) and "lexical islands" (smaller groups of words that are connected to each other, but not to the giant…

RFID: A Revolution in Automatic Data Recognition

ERIC Educational Resources Information Center

Deal, Walter F., III

2004-01-01

Radio frequency identification, or RFID, is a generic term for technologies that use radio waves to automatically identify people or objects. There are several methods of identification, but the most common is to store a serial number that identifies a person or object, and perhaps other information, on a microchip that is attached to an antenna…

Direct electronic probing of biological complexes formation

NASA Astrophysics Data System (ADS)

Macchia, Eleonora; Magliulo, Maria; Manoli, Kyriaki; Giordano, Francesco; Palazzo, Gerardo; Torsi, Luisa

2014-10-01

Functional bio-interlayer organic field - effect transistors (FBI-OFET), embedding streptavidin, avidin and neutravidin as bio-recognition element, have been studied to probe the electronic properties of protein complexes. The threshold voltage control has been achieved modifying the SiO2 gate diaelectric surface by means of the deposition of an interlayer of bio-recognition elements. A threshold voltage shift with respect to the unmodified dielectric surface toward more negative potential values has been found for the three different proteins, in agreement with their isoelectric points. The relative responses in terms of source - drain current, mobility and threshold voltage upon exposure to biotin of the FBI-OFET devices have been compared for the three bio-recognition elements.

Eye-movement assessment of the time course in facial expression recognition: Neurophysiological implications.

PubMed

Calvo, Manuel G; Nummenmaa, Lauri

2009-12-01

Happy, surprised, disgusted, angry, sad, fearful, and neutral faces were presented extrafoveally, with fixations on faces allowed or not. The faces were preceded by a cue word that designated the face to be saccaded in a two-alternative forced-choice discrimination task (2AFC; Experiments 1 and 2), or were followed by a probe word for recognition (Experiment 3). Eye tracking was used to decompose the recognition process into stages. Relative to the other expressions, happy faces (1) were identified faster (as early as 160 msec from stimulus onset) in extrafoveal vision, as revealed by shorter saccade latencies in the 2AFC task; (2) required less encoding effort, as indexed by shorter first fixations and dwell times; and (3) required less decision-making effort, as indicated by fewer refixations on the face after the recognition probe was presented. This reveals a happy-face identification advantage both prior to and during overt attentional processing. The results are discussed in relation to prior neurophysiological findings on latencies in facial expression recognition.

The contribution of discrete-trial naming and visual recognition to rapid automatized naming deficits of dyslexic children with and without a history of language delay

PubMed Central

Gasperini, Filippo; Brizzolara, Daniela; Cristofani, Paola; Casalini, Claudia; Chilosi, Anna Maria

2014-01-01

Children with Developmental Dyslexia (DD) are impaired in Rapid Automatized Naming (RAN) tasks, where subjects are asked to name arrays of high frequency items as quickly as possible. However the reasons why RAN speed discriminates DD from typical readers are not yet fully understood. Our study was aimed to identify some of the cognitive mechanisms underlying RAN-reading relationship by comparing one group of 32 children with DD with an age-matched control group of typical readers on a naming and a visual recognition task both using a discrete-trial methodology, in addition to a serial RAN task, all using the same stimuli (digits and colors). Results showed a significant slowness of DD children in both serial and discrete-trial naming (DN) tasks regardless of type of stimulus, but no difference between the two groups on the discrete-trial recognition task. Significant differences between DD and control participants in the RAN task disappeared when performance in the DN task was partialled out by covariance analysis for colors, but not for digits. The same pattern held in a subgroup of DD subjects with a history of early language delay (LD). By contrast, in a subsample of DD children without LD the RAN deficit was specific for digits and disappeared after slowness in DN was partialled out. Slowness in DN was more evident for LD than for noLD DD children. Overall, our results confirm previous evidence indicating a name-retrieval deficit as a cognitive impairment underlying RAN slowness in DD children. This deficit seems to be more marked in DD children with previous LD. Moreover, additional cognitive deficits specifically associated with serial RAN tasks have to be taken into account when explaining deficient RAN speed of these latter children. We suggest that partially different cognitive dysfunctions underpin superficially similar RAN impairments in different subgroups of DD subjects. PMID:25237301

Low-resolution expression recognition based on central oblique average CS-LBP with adaptive threshold

NASA Astrophysics Data System (ADS)

Han, Sheng; Xi, Shi-qiong; Geng, Wei-dong

2017-11-01

In order to solve the problem of low recognition rate of traditional feature extraction operators under low-resolution images, a novel algorithm of expression recognition is proposed, named central oblique average center-symmetric local binary pattern (CS-LBP) with adaptive threshold (ATCS-LBP). Firstly, the features of face images can be extracted by the proposed operator after pretreatment. Secondly, the obtained feature image is divided into blocks. Thirdly, the histogram of each block is computed independently and all histograms can be connected serially to create a final feature vector. Finally, expression classification is achieved by using support vector machine (SVM) classifier. Experimental results on Japanese female facial expression (JAFFE) database show that the proposed algorithm can achieve a recognition rate of 81.9% when the resolution is as low as 16×16, which is much better than that of the traditional feature extraction operators.

Time-resolved structural studies with serial crystallography: A new light on retinal proteins

PubMed Central

Panneels, Valérie; Wu, Wenting; Tsai, Ching-Ju; Nogly, Przemek; Rheinberger, Jan; Jaeger, Kathrin; Cicchetti, Gregor; Gati, Cornelius; Kick, Leonhard M.; Sala, Leonardo; Capitani, Guido; Milne, Chris; Padeste, Celestino; Pedrini, Bill; Li, Xiao-Dan; Standfuss, Jörg; Abela, Rafael; Schertler, Gebhard

2015-01-01

Structural information of the different conformational states of the two prototypical light-sensitive membrane proteins, bacteriorhodopsin and rhodopsin, has been obtained in the past by X-ray cryo-crystallography and cryo-electron microscopy. However, these methods do not allow for the structure determination of most intermediate conformations. Recently, the potential of X-Ray Free Electron Lasers (X-FELs) for tracking the dynamics of light-triggered processes by pump-probe serial femtosecond crystallography has been demonstrated using 3D-micron-sized crystals. In addition, X-FELs provide new opportunities for protein 2D-crystal diffraction, which would allow to observe the course of conformational changes of membrane proteins in a close-to-physiological lipid bilayer environment. Here, we describe the strategies towards structural dynamic studies of retinal proteins at room temperature, using injector or fixed-target based serial femtosecond crystallography at X-FELs. Thanks to recent progress especially in sample delivery methods, serial crystallography is now also feasible at synchrotron X-ray sources, thus expanding the possibilities for time-resolved structure determination. PMID:26798817

Serial position effects in the identification of letters, digits, and symbols.

PubMed

Tydgat, Ilse; Grainger, Jonathan

2009-04-01

In 6 experiments, the authors investigated the form of serial position functions for identification of letters, digits, and symbols presented in strings. The results replicated findings obtained with the target search paradigm, showing an interaction between the effects of serial position and type of stimulus, with symbols generating a distinct serial position function compared with letters and digits. When the task was 2-alternative forced choice, this interaction was driven almost exclusively by performance at the first position in the string, with letters and digits showing much higher levels of accuracy than symbols at this position. A final-position advantage was reinstated in Experiment 6 by placing the two alternative responses below the target string. The end-position (first and last positions) advantage for letters and digits compared with symbol stimuli was further confirmed with the bar-probe technique (postcued partial report) in Experiments 5 and 6. Overall, the results further support the existence of a specialized mechanism designed to optimize processing of strings of letters and digits by modifying the size and shape of retinotopic character detectors' receptive fields. (c) 2009 APA, all rights reserved.

Comparing the visual spans for faces and letters

PubMed Central

He, Yingchen; Scholz, Jennifer M.; Gage, Rachel; Kallie, Christopher S.; Liu, Tingting; Legge, Gordon E.

2015-01-01

The visual span—the number of adjacent text letters that can be reliably recognized on one fixation—has been proposed as a sensory bottleneck that limits reading speed (Legge, Mansfield, & Chung, 2001). Like reading, searching for a face is an important daily task that involves pattern recognition. Is there a similar limitation on the number of faces that can be recognized in a single fixation? Here we report on a study in which we measured and compared the visual-span profiles for letter and face recognition. A serial two-stage model for pattern recognition was developed to interpret the data. The first stage is characterized by factors limiting recognition of isolated letters or faces, and the second stage represents the interfering effect of nearby stimuli on recognition. Our findings show that the visual span for faces is smaller than that for letters. Surprisingly, however, when differences in first-stage processing for letters and faces are accounted for, the two visual spans become nearly identical. These results suggest that the concept of visual span may describe a common sensory bottleneck that underlies different types of pattern recognition. PMID:26129858

Memory evaluation in mild cognitive impairment using recall and recognition tests.

PubMed

Bennett, Ilana J; Golob, Edward J; Parker, Elizabeth S; Starr, Arnold

2006-11-01

Amnestic mild cognitive impairment (MCI) is a selective episodic memory deficit that often indicates early Alzheimer's disease. Episodic memory function in MCI is typically defined by deficits in free recall, but can also be tested using recognition procedures. To assess both recall and recognition in MCI, MCI (n = 21) and older comparison (n = 30) groups completed the USC-Repeatable Episodic Memory Test. Subjects memorized two verbally presented 15-item lists. One list was used for three free recall trials, immediately followed by yes/no recognition. The second list was used for three-alternative forced-choice recognition. Relative to the comparison group, MCI had significantly fewer hits and more false alarms in yes/no recognition, and were less accurate in forced-choice recognition. Signal detection analysis showed that group differences were not due to response bias. Discriminant function analysis showed that yes/no recognition was a better predictor of group membership than free recall or forced-choice measures. MCI subjects recalled fewer items than comparison subjects, with no group differences in repetitions, intrusions, serial position effects, or measures of recall strategy (subjective organization, recall consistency). Performance deficits on free recall and recognition in MCI suggest a combination of both tests may be useful for defining episodic memory impairment associated with MCI and early Alzheimer's disease.

The Role of the Ventral and Dorsal Pathways in Reading Chinese Characters and English Words

ERIC Educational Resources Information Center

Sun, Yafeng; Yang, Yanhui; Desroches, Amy S.; Liu, Li; Peng, Danling

2011-01-01

Previous literature in alphabetic languages suggests that the occipital-temporal region (the ventral pathway) is specialized for automatic parallel word recognition, whereas the parietal region (the dorsal pathway) is specialized for serial letter-by-letter reading (and). However, few studies have directly examined the role of the ventral and…

Exogenous temporal cues enhance recognition memory in an object-based manner.

PubMed

Ohyama, Junji; Watanabe, Katsumi

2010-11-01

Exogenous attention enhances the perception of attended items in both a space-based and an object-based manner. Exogenous attention also improves recognition memory for attended items in the space-based mode. However, it has not been examined whether object-based exogenous attention enhances recognition memory. To address this issue, we examined whether a sudden visual change in a task-irrelevant stimulus (an exogenous cue) would affect participants' recognition memory for items that were serially presented around a cued time. The results showed that recognition accuracy for an item was strongly enhanced when the visual cue occurred at the same location and time as the item (Experiments 1 and 2). The memory enhancement effect occurred when the exogenous visual cue and an item belonged to the same object (Experiments 3 and 4) and even when the cue was counterpredictive of the timing of an item to be asked about (Experiment 5). The present study suggests that an exogenous temporal cue automatically enhances the recognition accuracy for an item that is presented at close temporal proximity to the cue and that recognition memory enhancement occurs in an object-based manner.

Searching for serial refreshing in working memory: Using response times to track the content of the focus of attention over time.

PubMed

Vergauwe, Evie; Hardman, Kyle O; Rouder, Jeffrey N; Roemer, Emily; McAllaster, Sara; Cowan, Nelson

2016-12-01

One popular idea is that, to support the maintenance of a set of elements over brief periods of time, the focus of attention rotates among the different elements, thereby serially refreshing the content of working memory (WM). In the research reported here, probe letters were presented between to-be-remembered letters, and response times to these probes were used to infer the status of the different items in WM. If the focus of attention cycles from one item to the next, its content should be different at different points in time, and this should be reflected in a change in the response time patterns over time. Across a set of four experiments, we demonstrated a striking pattern of invariance in the response time patterns over time, suggesting either that the content of the focus of attention did not change over time or that response times cannot be used to infer the content of the focus of attention. We discuss how this pattern constrains models of WM, attention, and human information processing.

Deceleration of probe beam by stage bias potential improves resolution of serial block-face scanning electron microscopic images.

PubMed

Bouwer, James C; Deerinck, Thomas J; Bushong, Eric; Astakhov, Vadim; Ramachandra, Ranjan; Peltier, Steven T; Ellisman, Mark H

2017-01-01

Serial block-face scanning electron microscopy (SBEM) is quickly becoming an important imaging tool to explore three-dimensional biological structure across spatial scales. At probe-beam-electron energies of 2.0 keV or lower, the axial resolution should improve, because there is less primary electron penetration into the block face. More specifically, at these lower energies, the interaction volume is much smaller, and therefore, surface detail is more highly resolved. However, the backscattered electron yield for metal contrast agents and the backscattered electron detector sensitivity are both sub-optimal at these lower energies, thus negating the gain in axial resolution. We found that the application of a negative voltage (reversal potential) applied to a modified SBEM stage creates a tunable electric field at the sample. This field can be used to decrease the probe-beam-landing energy and, at the same time, alter the trajectory of the signal to increase the signal collected by the detector. With decelerated low landing-energy electrons, we observed that the probe-beam-electron-penetration depth was reduced to less than 30 nm in epoxy-embedded biological specimens. Concurrently, a large increase in recorded signal occurred due to the re-acceleration of BSEs in the bias field towards the objective pole piece where the detector is located. By tuning the bias field, we were able to manipulate the trajectories of the  primary and secondary electrons, enabling the spatial discrimination of these signals using an advanced ring-type BSE detector configuration or a standard monolithic BSE detector coupled with a blocking aperture.

A unique dual recognition hairpin probe mediated fluorescence amplification method for sensitive detection of uracil-DNA glycosylase and endonuclease IV activities.

PubMed

Wu, Yushu; Yan, Ping; Xu, Xiaowen; Jiang, Wei

2016-03-07

Uracil-DNA glycosylase (UDG) and endonuclease IV (Endo IV) play cooperative roles in uracil base-excision repair (UBER) and inactivity of either will interrupt the UBER to cause disease. Detection of UDG and Endo IV activities is crucial to evaluate the UBER process in fundamental research and diagnostic application. Here, a unique dual recognition hairpin probe mediated fluorescence amplification method was developed for sensitively and selectively detecting UDG and Endo IV activities. For detecting UDG activity, the uracil base in the probe was excised by the target enzyme to generate an apurinic/apyrimidinic (AP) site, achieving the UDG recognition. Then, the AP site was cleaved by a tool enzyme Endo IV, releasing a primer to trigger rolling circle amplification (RCA) reaction. Finally, the RCA reaction produced numerous repeated G-quadruplex sequences, which interacted with N-methyl-mesoporphyrin IX to generate an enhanced fluorescence signal. Alternatively, for detecting Endo IV activity, the uracil base in the probe was first converted into an AP site by a tool enzyme UDG. Next, the AP site was cleaved by the target enzyme, achieving the Endo IV recognition. The signal was then generated and amplified in the same way as those in the UDG activity assay. The detection limits were as low as 0.00017 U mL(-1) for UDG and 0.11 U mL(-1) for Endo IV, respectively. Moreover, UDG and Endo IV can be well distinguished from their analogs. This method is beneficial for properly evaluating the UBER process in function studies and disease prognoses.

Sublexical Processing in Visual Recognition of Chinese Characters: Evidence from Repetition Blindness for Subcharacter Components

ERIC Educational Resources Information Center

Yeh, Su-Ling; Li, Jing-Ling

2004-01-01

Repetition blindness (RB) refers to the failure to detect the second occurrence of a repeated item in rapid serial visual presentation (RSVP). In two experiments using RSVP, the ability to report two critical characters was found to be impaired when these two characters were identical (Experiment 1) or similar by sharing one repeated component…

Recognition- and Reactivity-Based Fluorescent Probes for Studying Transition Metal Signaling in Living Systems

PubMed Central

2015-01-01

Conspectus Metals are essential for life, playing critical roles in all aspects of the central dogma of biology (e.g., the transcription and translation of nucleic acids and synthesis of proteins). Redox-inactive alkali, alkaline earth, and transition metals such as sodium, potassium, calcium, and zinc are widely recognized as dynamic signals, whereas redox-active transition metals such as copper and iron are traditionally thought of as sequestered by protein ligands, including as static enzyme cofactors, in part because of their potential to trigger oxidative stress and damage via Fenton chemistry. Metals in biology can be broadly categorized into two pools: static and labile. In the former, proteins and other macromolecules tightly bind metals; in the latter, metals are bound relatively weakly to cellular ligands, including proteins and low molecular weight ligands. Fluorescent probes can be useful tools for studying the roles of transition metals in their labile forms. Probes for imaging transition metal dynamics in living systems must meet several stringent criteria. In addition to exhibiting desirable photophysical properties and biocompatibility, they must be selective and show a fluorescence turn-on response to the metal of interest. To meet this challenge, we have pursued two general strategies for metal detection, termed “recognition” and “reactivity”. Our design of transition metal probes makes use of a recognition-based approach for copper and nickel and a reactivity-based approach for cobalt and iron. This Account summarizes progress in our laboratory on both the development and application of fluorescent probes to identify and study the signaling roles of transition metals in biology. In conjunction with complementary methods for direct metal detection and genetic and/or pharmacological manipulations, fluorescent probes for transition metals have helped reveal a number of principles underlying transition metal dynamics. In this Account, we give three recent examples from our laboratory and collaborations in which applications of chemical probes reveal that labile copper contributes to various physiologies. The first example shows that copper is an endogenous regulator of neuronal activity, the second illustrates cellular prioritization of mitochondrial copper homeostasis, and the third identifies the “cuprosome” as a new copper storage compartment in Chlamydomonas reinhardtii green algae. Indeed, recognition- and reactivity-based fluorescent probes have helped to uncover new biological roles for labile transition metals, and the further development of fluorescent probes, including ones with varied Kd values and new reaction triggers and recognition receptors, will continue to reveal exciting and new biological roles for labile transition metals. PMID:26215055

LIPS database with LIPService: a microscopic image database of intracellular structures in Arabidopsis guard cells.

PubMed

Higaki, Takumi; Kutsuna, Natsumaro; Hasezawa, Seiichiro

2013-05-16

Intracellular configuration is an important feature of cell status. Recent advances in microscopic imaging techniques allow us to easily obtain a large number of microscopic images of intracellular structures. In this circumstance, automated microscopic image recognition techniques are of extreme importance to future phenomics/visible screening approaches. However, there was no benchmark microscopic image dataset for intracellular organelles in a specified plant cell type. We previously established the Live Images of Plant Stomata (LIPS) database, a publicly available collection of optical-section images of various intracellular structures of plant guard cells, as a model system of environmental signal perception and transduction. Here we report recent updates to the LIPS database and the establishment of a database table, LIPService. We updated the LIPS dataset and established a new interface named LIPService to promote efficient inspection of intracellular structure configurations. Cell nuclei, microtubules, actin microfilaments, mitochondria, chloroplasts, endoplasmic reticulum, peroxisomes, endosomes, Golgi bodies, and vacuoles can be filtered using probe names or morphometric parameters such as stomatal aperture. In addition to the serial optical sectional images of the original LIPS database, new volume-rendering data for easy web browsing of three-dimensional intracellular structures have been released to allow easy inspection of their configurations or relationships with cell status/morphology. We also demonstrated the utility of the new LIPS image database for automated organelle recognition of images from another plant cell image database with image clustering analyses. The updated LIPS database provides a benchmark image dataset for representative intracellular structures in Arabidopsis guard cells. The newly released LIPService allows users to inspect the relationship between organellar three-dimensional configurations and morphometrical parameters.

Real-time dosimeter employed to evaluate the half-value layer in CT

NASA Astrophysics Data System (ADS)

McKenney, Sarah E.; Seibert, J. Anthony; Burkett, George W.; Gelskey, Dale; Sunde, Paul B.; Newman, James D.; Boone, John M.

2014-01-01

Half-value layer (HVL) measurements on commercial whole body computer tomography (CT) scanners require serial measurements and, in many institutions, the presence of a service engineer. An assembly of aluminum filters (AAF), designed to be used in conjunction with a real-time dosimeter, was developed to provide estimates of the HVL using clinical protocols. Two real-time dose probes, a solid-state and air ionization chamber, were examined. The AAF consisted of eight rectangular filters of high-purity aluminum (Type 1100), symmetrically positioned to form a cylindrical ‘cage’ around the probe's detective volume. The incident x-ray beam was attenuated by varying thicknesses of aluminum filters as the gantry completed a minimum of one rotation. Measurements employing real-time chambers were conducted both in service mode and with a routine abdomen/pelvis protocol for several combinations of x-ray tube potentials and bow tie filters. These measurements were validated against conventional serial HVL measurements. The average relative difference between the HVL measurements using the two methods was less than 5% when using a 122 mm diameter AAF; relative differences were reduced to 1.1% when the diameter was increased to 505 mm, possibly due to reduced scatter contamination. Use of a real-time dose probe and the AAF allowed for time-efficient measurements of beam quality on a clinical CT scanner using clinical protocols.

A Thiazole Coumarin (TC) Turn-On Fluorescence Probe for AT-Base Pair Detection and Multipurpose Applications in Different Biological Systems

NASA Astrophysics Data System (ADS)

Narayanaswamy, Nagarjun; Kumar, Manoj; Das, Sadhan; Sharma, Rahul; Samanta, Pralok K.; Pati, Swapan K.; Dhar, Suman K.; Kundu, Tapas K.; Govindaraju, T.

2014-09-01

Sequence-specific recognition of DNA by small turn-on fluorescence probes is a promising tool for bioimaging, bioanalytical and biomedical applications. Here, the authors report a novel cell-permeable and red fluorescent hemicyanine-based thiazole coumarin (TC) probe for DNA recognition, nuclear staining and cell cycle analysis. TC exhibited strong fluorescence enhancement in the presence of DNA containing AT-base pairs, but did not fluoresce with GC sequences, single-stranded DNA, RNA and proteins. The fluorescence staining of HeLa S3 and HEK 293 cells by TC followed by DNase and RNase digestion studies depicted the selective staining of DNA in the nucleus over the cytoplasmic region. Fluorescence-activated cell sorting (FACS) analysis by flow cytometry demonstrated the potential application of TC in cell cycle analysis in HEK 293 cells. Metaphase chromosome and malaria parasite DNA imaging studies further confirmed the in vivo diagnostic and therapeutic applications of probe TC. Probe TC may find multiple applications in fluorescence spectroscopy, diagnostics, bioimaging and molecular and cell biology.

A Thiazole Coumarin (TC) Turn-On Fluorescence Probe for AT-Base Pair Detection and Multipurpose Applications in Different Biological Systems

PubMed Central

Narayanaswamy, Nagarjun; Kumar, Manoj; Das, Sadhan; Sharma, Rahul; Samanta, Pralok K.; Pati, Swapan K.; Dhar, Suman K.; Kundu, Tapas K.; Govindaraju, T.

2014-01-01

Sequence-specific recognition of DNA by small turn-on fluorescence probes is a promising tool for bioimaging, bioanalytical and biomedical applications. Here, the authors report a novel cell-permeable and red fluorescent hemicyanine-based thiazole coumarin (TC) probe for DNA recognition, nuclear staining and cell cycle analysis. TC exhibited strong fluorescence enhancement in the presence of DNA containing AT-base pairs, but did not fluoresce with GC sequences, single-stranded DNA, RNA and proteins. The fluorescence staining of HeLa S3 and HEK 293 cells by TC followed by DNase and RNase digestion studies depicted the selective staining of DNA in the nucleus over the cytoplasmic region. Fluorescence-activated cell sorting (FACS) analysis by flow cytometry demonstrated the potential application of TC in cell cycle analysis in HEK 293 cells. Metaphase chromosome and malaria parasite DNA imaging studies further confirmed the in vivo diagnostic and therapeutic applications of probe TC. Probe TC may find multiple applications in fluorescence spectroscopy, diagnostics, bioimaging and molecular and cell biology. PMID:25252596

Increased susceptibility to proactive interference in adults with dyslexia?

PubMed

Bogaerts, Louisa; Szmalec, Arnaud; Hachmann, Wibke M; Page, Mike P A; Woumans, Evy; Duyck, Wouter

2015-01-01

Recent findings show that people with dyslexia have an impairment in serial-order memory. Based on these findings, the present study aimed to test the hypothesis that people with dyslexia have difficulties dealing with proactive interference (PI) in recognition memory. A group of 25 adults with dyslexia and a group of matched controls were subjected to a 2-back recognition task, which required participants to indicate whether an item (mis)matched the item that had been presented 2 trials before. PI was elicited using lure trials in which the item matched the item in the 3-back position instead of the targeted 2-back position. Our results demonstrate that the introduction of lure trials affected 2-back recognition performance more severely in the dyslexic group than in the control group, suggesting greater difficulty in resisting PI in dyslexia.

Crowding by a single bar: probing pattern recognition mechanisms in the visual periphery.

PubMed

Põder, Endel

2014-11-06

Whereas visual crowding does not greatly affect the detection of the presence of simple visual features, it heavily inhibits combining them into recognizable objects. Still, crowding effects have rarely been directly related to general pattern recognition mechanisms. In this study, pattern recognition mechanisms in visual periphery were probed using a single crowding feature. Observers had to identify the orientation of a rotated T presented briefly in a peripheral location. Adjacent to the target, a single bar was presented. The bar was either horizontal or vertical and located in a random direction from the target. It appears that such a crowding bar has very strong and regular effects on the identification of the target orientation. The observer's responses are determined by approximate relative positions of basic visual features; exact image-based similarity to the target is not important. A version of the "standard model" of object recognition with second-order features explains the main regularities of the data. © 2014 ARVO.

Evidence for view-invariant face recognition units in unfamiliar face learning.

PubMed

Etchells, David B; Brooks, Joseph L; Johnston, Robert A

2017-05-01

Many models of face recognition incorporate the idea of a face recognition unit (FRU), an abstracted representation formed from each experience of a face which aids recognition under novel viewing conditions. Some previous studies have failed to find evidence of this FRU representation. Here, we report three experiments which investigated this theoretical construct by modifying the face learning procedure from that in previous work. During learning, one or two views of previously unfamiliar faces were shown to participants in a serial matching task. Later, participants attempted to recognize both seen and novel views of the learned faces (recognition phase). Experiment 1 tested participants' recognition of a novel view, a day after learning. Experiment 2 was identical, but tested participants on the same day as learning. Experiment 3 repeated Experiment 1, but tested participants on a novel view that was outside the rotation of those views learned. Results revealed a significant advantage, across all experiments, for recognizing a novel view when two views had been learned compared to single view learning. The observed view invariance supports the notion that an FRU representation is established during multi-view face learning under particular learning conditions.

Task-switching cost and repetition priming: two overlooked confounds in the first-set procedure of the Sternberg paradigm and how they affect memory set-size effects.

PubMed

Jou, Jerwen

2014-10-01

Subjects performed Sternberg-type memory recognition tasks (Sternberg paradigm) in four experiments. Category-instance names were used as learning and testing materials. Sternberg's original experiments demonstrated a linear relation between reaction time (RT) and memory-set size (MSS). A few later studies found no relation, and other studies found a nonlinear relation (logarithmic) between the two variables. These deviations were used as evidence undermining Sternberg's serial scan theory. This study identified two confounding variables in the fixed-set procedure of the paradigm (where multiple probes are presented at test for a learned memory set) that could generate a MSS RT function that was either flat or logarithmic rather than linearly increasing. These two confounding variables were task-switching cost and repetition priming. The former factor worked against smaller memory sets and in favour of larger sets whereas the latter factor worked in the opposite way. Results demonstrated that a null or a logarithmic RT-to-MSS relation could be the artefact of the combined effects of these two variables. The Sternberg paradigm has been used widely in memory research, and a thorough understanding of the subtle methodological pitfalls is crucial. It is suggested that a varied-set procedure (where only one probe is presented at test for a learned memory set) is a more contamination-free procedure for measuring the MSS effects, and that if a fixed-set procedure is used, it is worthwhile examining the RT function of the very first trials across the MSSs, which are presumably relatively free of contamination by the subsequent trials.

Acute fluoxetine modulates emotional processing in young adult volunteers.

PubMed

Capitão, L P; Murphy, S E; Browning, M; Cowen, P J; Harmer, C J

2015-08-01

Fluoxetine is generally regarded as the first-line pharmacological treatment for young people, as it is believed to show a more favourable benefit:risk ratio than other antidepressants. However, the mechanisms through which fluoxetine influences symptoms in youth have been little investigated. This study examined whether acute administration of fluoxetine in a sample of young healthy adults altered the processing of affective information, including positive, sad and anger cues. A total of 35 male and female volunteers aged between 18 and 21 years old were randomized to receive a single 20 mg dose of fluoxetine or placebo. At 6 h after administration, participants completed a facial expression recognition task, an emotion-potentiated startle task, an attentional dot-probe task and the Rapid Serial Visual Presentation. Subjective ratings of mood, anxiety and side effects were also taken pre- and post-fluoxetine/placebo administration. Relative to placebo-treated participants, participants receiving fluoxetine were less accurate at identifying anger and sadness and did not show the emotion-potentiated startle effect. There were no overall significant effects of fluoxetine on subjective ratings of mood. Fluoxetine can modulate emotional processing after a single dose in young adults. This pattern of effects suggests a potential cognitive mechanism for the greater benefit:risk ratio of fluoxetine in adolescent patients.

Short-term memory for order but not for item information is impaired in developmental dyslexia.

PubMed

Hachmann, Wibke M; Bogaerts, Louisa; Szmalec, Arnaud; Woumans, Evy; Duyck, Wouter; Job, Remo

2014-07-01

Recent findings suggest that people with dyslexia experience difficulties with the learning of serial order information during the transition from short- to long-term memory (Szmalec et al. Journal of Experimental Psychology: Learning, Memory, & Cognition 37(5): 1270-1279, 2011). At the same time, models of short-term memory increasingly incorporate a distinction of order and item processing (Majerus et al. Cognition 107: 395-419, 2008). The current study is aimed to investigate whether serial order processing deficiencies in dyslexia can be traced back to a selective impairment of short-term memory for serial order and whether this impairment also affects processing beyond the verbal domain. A sample of 26 adults with dyslexia and a group of age and IQ-matched controls participated in a 2 × 2 × 2 experiment in which we assessed short-term recognition performance for order and item information, using both verbal and nonverbal material. Our findings indicate that, irrespective of the type of material, participants with dyslexia recalled the individual items with the same accuracy as the matched control group, whereas the ability to recognize the serial order in which those items were presented appeared to be affected in the dyslexia group. We conclude that dyslexia is characterized by a selective impairment of short-term memory for serial order, but not for item information, and discuss the integration of these findings into current theoretical views on dyslexia and its associated dysfunctions.

Face recognition by applying wavelet subband representation and kernel associative memory.

PubMed

Zhang, Bai-Ling; Zhang, Haihong; Ge, Shuzhi Sam

2004-01-01

In this paper, we propose an efficient face recognition scheme which has two features: 1) representation of face images by two-dimensional (2-D) wavelet subband coefficients and 2) recognition by a modular, personalised classification method based on kernel associative memory models. Compared to PCA projections and low resolution "thumb-nail" image representations, wavelet subband coefficients can efficiently capture substantial facial features while keeping computational complexity low. As there are usually very limited samples, we constructed an associative memory (AM) model for each person and proposed to improve the performance of AM models by kernel methods. Specifically, we first applied kernel transforms to each possible training pair of faces sample and then mapped the high-dimensional feature space back to input space. Our scheme using modular autoassociative memory for face recognition is inspired by the same motivation as using autoencoders for optical character recognition (OCR), for which the advantages has been proven. By associative memory, all the prototypical faces of one particular person are used to reconstruct themselves and the reconstruction error for a probe face image is used to decide if the probe face is from the corresponding person. We carried out extensive experiments on three standard face recognition datasets, the FERET data, the XM2VTS data, and the ORL data. Detailed comparisons with earlier published results are provided and our proposed scheme offers better recognition accuracy on all of the face datasets.

Short-Term Serial Tactual Recall: Effects of Grouping on Tactually Probed Recall of Braille Letters and Nonsense Shapes by Blind Children

ERIC Educational Resources Information Center

Millar, Susanna

1978-01-01

This research tested the hypothesis that grouping has adverse effects on the recall of tactual shapes but facilitates the recall of tactual letters on the assumption that this depends on different processes. A further question was the relation of grouping to letter recall span (set-size).

Probed Serial Recall in Williams Syndrome: Lexical Influences on Phonological Short-Term Memory

ERIC Educational Resources Information Center

Brock, Jan; McCormack, Teresa; Boucher, Jill

2005-01-01

Williams syndrome is a genetic disorder that, it has been claimed, results in an unusual pattern of linguistic strengths and weaknesses. The current study investigated the hypothesis that there is a reduced influence of lexical knowledge on phonological short-term memory in Williams syndrome. Fourteen children with Williams syndrome and 2…

Primacy Effects in Short-Term Memory with the Mentally Retarded.

ERIC Educational Resources Information Center

Detterman, Douglas K.

This paper reports on two experiments conducted in an attempt to extend findings by Ellis which suggest a rehearsal deficit in mentally retarded subjects. In experiment one, mentally retarded subjects saw nine stimuli in a serial position probe task for either two, four, or six seconds each. Performances for the two and four second-per-item rates…

Impact of Auditory Selective Attention on Verbal Short-Term Memory and Vocabulary Development

ERIC Educational Resources Information Center

Majerus, Steve; Heiligenstein, Lucie; Gautherot, Nathalie; Poncelet, Martine; Van der Linden, Martial

2009-01-01

This study investigated the role of auditory selective attention capacities as a possible mediator of the well-established association between verbal short-term memory (STM) and vocabulary development. A total of 47 6- and 7-year-olds were administered verbal immediate serial recall and auditory attention tasks. Both task types probed processing…

Combinatorial approaches to gene recognition.

PubMed

Roytberg, M A; Astakhova, T V; Gelfand, M S

1997-01-01

Recognition of genes via exon assembly approaches leads naturally to the use of dynamic programming. We consider the general graph-theoretical formulation of the exon assembly problem and analyze in detail some specific variants: multicriterial optimization in the case of non-linear gene-scoring functions; context-dependent schemes for scoring exons and related procedures for exon filtering; and highly specific recognition of arbitrary gene segments, oligonucleotide probes and polymerase chain reaction (PCR) primers.

Position feedback control system

DOEpatents

Bieg, Lothar F.; Jokiel, Jr., Bernhard; Ensz, Mark T.; Watson, Robert D.

2003-01-01

Disclosed is a system and method for independently evaluating the spatial positional performance of a machine having a movable member, comprising an articulated coordinate measuring machine comprising: a first revolute joint; a probe arm, having a proximal end rigidly attached to the first joint, and having a distal end with a probe tip attached thereto, wherein the probe tip is pivotally mounted to the movable machine member; a second revolute joint; a first support arm serially connecting the first joint to the second joint; and coordinate processing means, operatively connected to the first and second revolute joints, for calculating the spatial coordinates of the probe tip; means for kinematically constraining the articulated coordinate measuring machine to a working surface; and comparator means, in operative association with the coordinate processing means and with the movable machine, for comparing the true position of the movable machine member, as measured by the true position of the probe tip, with the desired position of the movable machine member.

Fast and accurate face recognition based on image compression

NASA Astrophysics Data System (ADS)

Zheng, Yufeng; Blasch, Erik

2017-05-01

Image compression is desired for many image-related applications especially for network-based applications with bandwidth and storage constraints. The face recognition community typical reports concentrate on the maximal compression rate that would not decrease the recognition accuracy. In general, the wavelet-based face recognition methods such as EBGM (elastic bunch graph matching) and FPB (face pattern byte) are of high performance but run slowly due to their high computation demands. The PCA (Principal Component Analysis) and LDA (Linear Discriminant Analysis) algorithms run fast but perform poorly in face recognition. In this paper, we propose a novel face recognition method based on standard image compression algorithm, which is termed as compression-based (CPB) face recognition. First, all gallery images are compressed by the selected compression algorithm. Second, a mixed image is formed with the probe and gallery images and then compressed. Third, a composite compression ratio (CCR) is computed with three compression ratios calculated from: probe, gallery and mixed images. Finally, the CCR values are compared and the largest CCR corresponds to the matched face. The time cost of each face matching is about the time of compressing the mixed face image. We tested the proposed CPB method on the "ASUMSS face database" (visible and thermal images) from 105 subjects. The face recognition accuracy with visible images is 94.76% when using JPEG compression. On the same face dataset, the accuracy of FPB algorithm was reported as 91.43%. The JPEG-compressionbased (JPEG-CPB) face recognition is standard and fast, which may be integrated into a real-time imaging device.

Foldable polymers as probes

DOEpatents

Li, Alexander D. Q. [Pullman, WA; Wang, Wei [Pullman, WA

2007-07-03

Disclosed herein are novel probes, which can be used to detect and identify target molecules of interest in a sample. The disclosed probes can be used to monitor conformational changes induced by molecular recognition events in addition to providing signaling the presence and/or identity of a target molecule. Methods, including solid phase synthesis techniques, for making probe molecules that exhibit changes in their optical properties upon target molecule binding are described in the disclosure. Also disclosed herein are novel chromophore moieties, which have tailored fluorescent emission spectra.

Foldable polymers as probes

DOEpatents

Li, Alexander D. Q. [Pullman, WA; Wang, Wei [Pullman, WA

2009-07-07

Disclosed herein are novel probes, which can be used to detect and identify target molecules of interest in a sample. The disclosed probes can be used to monitor conformational changes induced by molecular recognition events in addition to providing signaling the presence and/or identity of a target molecule. Methods, including solid phase synthesis techniques, for making probe molecules that exhibit changes in their optical properties upon target molecule binding are described in the disclosure. Also disclosed herein are novel chromophore moieties, which have tailored fluorescent emission spectra.

Probabilistic and Other Neural Nets in Multi-Hole Probe Calibration and Flow Angularity Pattern Recognition

NASA Technical Reports Server (NTRS)

Baskaran, Subbiah; Ramachandran, Narayanan; Noever, David

1998-01-01

The use of probabilistic (PNN) and multilayer feed forward (MLFNN) neural networks are investigated for calibration of multi-hole pressure probes and the prediction of associated flow angularity patterns in test flow fields. Both types of networks are studied in detail for their calibration and prediction characteristics. The current formalism can be applied to any multi-hole probe, however the test results for the most commonly used five-hole Cone and Prism probe types alone are reported in this article.

Information-Processing Correlates of Computer-Assisted Word Learning by Mentally Retarded Students.

ERIC Educational Resources Information Center

Conners, Frances A.; Detterman, Douglas K.

1987-01-01

Nineteen moderately/severely retarded students (ages 9-22) completed ten 15-minute computer-assisted instruction sessions and seven basic cognitive tasks measuring simple learning, choice reaction time, relearning, probed recall, stimulus discrimination, tachictoscopic threshold, and recognition memory. Stimulus discrimination, probed recall, and…

Recognition Imaging with a DNA Aptamer

PubMed Central

Lin, Liyun; Wang, Hongda; Liu, Yan; Yan, Hao; Lindsay, Stuart

2006-01-01

We have used a DNA-aptamer tethered to an atomic force microscope probe to carry out recognition imaging of IgE molecules attached to a mica substrate. The recognition was efficient (∼90%) and specific, being blocked by injection of IgE molecules in solution, and not being interfered with by high concentrations of a second protein. The signal/noise ratio of the recognition signal was better than that obtained with antibodies, despite the fact that the average force required to break the aptamer-protein bonds was somewhat smaller. PMID:16513776

Imaging burst kinetics and spatial coordination during serial killing by single natural killer cells

PubMed Central

Choi, Paul J.; Mitchison, Timothy J.

2013-01-01

Cytotoxic lymphocytes eliminate virus-infected and cancerous cells by immune recognition and killing through the perforin-granzyme pathway. Traditional killing assays measure average target cell lysis at fixed times and high effector:target ratios. Such assays obscure kinetic details that might reveal novel physiology. We engineered target cells to report on granzyme activity, used very low effector:target ratios to observe potential serial killing, and performed low magnification time-lapse imaging to reveal time-dependent statistics of natural killer (NK) killing at the single-cell level. Most kills occurred during serial killing, and a single NK cell killed up to 10 targets over a 6-h assay. The first kill was slower than subsequent kills, especially on poor targets, or when NK signaling pathways were partially inhibited. Spatial analysis showed that sequential kills were usually adjacent. We propose that NK cells integrate signals from the previous and current target, possibly by simultaneous contact. The resulting burst kinetics and spatial coordination may control the activity of NK cells in tissues. PMID:23576740

A light-up probe with aggregation-induced emission characteristics (AIE) for selective imaging, naked-eye detection and photodynamic killing of Gram-positive bacteria.

PubMed

Feng, Guangxue; Yuan, Youyong; Fang, Hu; Zhang, Ruoyu; Xing, Bengang; Zhang, Guanxin; Zhang, Deqing; Liu, Bin

2015-08-11

We report the design and synthesis of a red fluorescent AIE light-up probe for selective recognition, naked-eye detection, and image-guided photodynamic killing of Gram-positive bacteria, including vancomycin-resistant Enterococcus strains.

A Fluorescent Hypochlorite Probe Built on 1,10-Phenanthroline Scaffold and its Ion Recognition Features.

PubMed

Algi, Melek Pamuk

2016-03-01

In this study, the synthesis of 7-((Hydroxyimino)methyl)-1,10-phenanthroline-4-carbaldehyde oxime (1) in two steps starting from 4,7-dimethyl-1,10-phenanthroline (2) is reported. It is found that compound 1 can be used as a fluorogenic probe for the detection of hypochlorite ion in aqueous solution. NMR and mass spectral analysis indicate that probe 1 undergoes a chemical transformation through its oxime units upon treatment with hypochlorite, which results in a remarkable enhancement of the emission intensity. Also, metal ion recognition properties of probe 1 is investigated. It is noted that compound 1 is responsive to Zn(2+), Cd(2+), Ni(2+) and Cu(2+) metal ions, which reduced the emission intensity under identical conditions. Graphical Abstract The design, synthesis and properties of a new fluorescent hypochlorite probe is described. It is found that probe 1 immediately undergoes an oxidation reaction with NaClO through its oxime units in 0.1 M Na2CO3-NaHCO3 buffer containing DMF (pH = 9.0, 30:1 v/v) at room temperature, which resulted in a remarkable enhancement of the emission intensity. It is noteworthy that this novel probe 1 is highly selective to hypochlorite ion when compared to some other ROS and anions. On the other hand, probe 1 also induces turn-off fluorogenic responses to metal ions such as Zn(2+), Cd(2+), Ni(2+) and Cu(2+) ions under identical conditions.

When does a good working memory counteract proactive interference? Surprising evidence from a probe recognition task.

PubMed

Cowan, Nelson; Saults, J Scott

2013-02-01

It is often proposed that individuals with high working memory span overcome proactive interference (PI) from previous trials, saving working memory for task-relevant items. We examined this hypothesis in word-list probe recognition. We found no difference in PI related to span. Instead, ex-gaussian analysis of reaction time showed speed advantages for high spans specific to short lists (3 or 4 items) but absent from longer lists (6 or 8 items). We suggest that high-span advantages in reaction time are based on finesse during easy trials, not on overcoming PI. 2013 APA, all rights reserved

Recent Progress in Fluorescent Imaging Probes

PubMed Central

Pak, Yen Leng; Swamy, K. M. K.; Yoon, Juyoung

2015-01-01

Due to the simplicity and low detection limit, especially the bioimaging ability for cells, fluorescence probes serve as unique detection methods. With the aid of molecular recognition and specific organic reactions, research on fluorescent imaging probes has blossomed during the last decade. Especially, reaction based fluorescent probes have been proven to be highly selective for specific analytes. This review highlights our recent progress on fluorescent imaging probes for biologically important species, such as biothiols, reactive oxygen species, reactive nitrogen species, metal ions including Zn2+, Hg2+, Cu2+ and Au3+, and anions including cyanide and adenosine triphosphate (ATP). PMID:26402684

Recent Progress in Fluorescent Imaging Probes.

PubMed

Pak, Yen Leng; Swamy, K M K; Yoon, Juyoung

2015-09-22

Due to the simplicity and low detection limit, especially the bioimaging ability for cells, fluorescence probes serve as unique detection methods. With the aid of molecular recognition and specific organic reactions, research on fluorescent imaging probes has blossomed during the last decade. Especially, reaction based fluorescent probes have been proven to be highly selective for specific analytes. This review highlights our recent progress on fluorescent imaging probes for biologically important species, such as biothiols, reactive oxygen species, reactive nitrogen species, metal ions including Zn(2+), Hg(2+), Cu(2+) and Au(3+), and anions including cyanide and adenosine triphosphate (ATP).

Recognition of DNA abasic site nanocavity by fluorophore-switched probe: Suitable for all sequence environments

NASA Astrophysics Data System (ADS)

Wang, Ying; Hu, Yuehua; Wu, Tao; Zhang, Lihua; Liu, Hua; Zhou, Xiaoshun; Shao, Yong

2016-01-01

Removal of a damaged base in DNA produces an abasic site (AP site) nanocavity. If left un-repaired in vivo by the specific enzyme, this nanocavity will result in nucleotide mutation in the following DNA replication. Therefore, selective recognition of AP site nanocavity by small molecules is important for identification of such DNA damage and development of genetic drugs. In this work, we investigate the fluorescence behavior of isoquinoline alkaloids including palmatine (PAL), berberine (BER), epiberberine (EPI), jatrorrhizine (JAT), coptisine (COP), coralyne (COR), worenine (WOR), berberrubine (BEU), sanguinarine (SAN), chelerythrine (CHE), and nitidine (NIT) upon binding with the AP nanocavity. PAL is screened out as the most efficient fluorophore-switched probe to recognize the AP nanocavity over the fully matched DNA. Its fluorescence enhancement occurs for all of the AP nanocavity sequence environments, which has not been achieved by the previously used probes. The bridged π conjugation effect should partially contribute to the AP nanocavity-specific fluorescence, as opposed to the solvent effect. Due to the strong binding with the AP nanocavity, PAL will find wide applications in the DNA damage recognition and sensor development.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diaz, Aaron A.; Chamberlin, Clyde E.; Edwards, Matthew K.

This section of the Joint summary technical letter report (TLR) describes work conducted at the Pacific Northwest National Laboratory (PNNL) during FY 2016 (FY16) on the under-sodium viewing (USV) PNNL project 58745, work package AT-16PN230102. This section of the TLR satisfies PNNL’s M3AT-16PN2301025 milestone and is focused on summarizing the design, development, and evaluation of two different phased-array ultrasonic testing (PA-UT) probe designs—a two-dimensional (2D) matrix phased-array probe, and two one-dimensional (1D) linear array probes, referred to as serial number 4 (SN4) engineering test units (ETUs). The 2D probe is a pulse-echo (PE), 32×2, 64-element matrix phased-array ETU. The 1Dmore » probes are 32×1 element linear array ETUs. This TLR also provides the results from a performance demonstration (PD) of in-sodium target detection trials at 260°C using both probe designs. This effort continues the iterative evolution supporting the longer term goal of producing and demonstrating a pre-manufacturing prototype ultrasonic probe that possesses the fundamental performance characteristics necessary to enable the development of a high-temperature sodium-cooled fast reactor (SFR) inspection system for in-sodium detection and imaging.« less

The Development and Use of Memory Strategies by Deaf Children and Adults.

ERIC Educational Resources Information Center

Liben, Lynn S.

The availability and application of particular memory strategies by deaf children and adults was examined. In the first study, 20 younger (mean age, 6 years, 3 months) and 20 older (8 years, 8 months) children's use of rehearsal strategies was examined with a serial probe task. All four types of stimuli (animals, nonsense shapes, hands, print)…

Asynchronous Communication of TLNS3DMB Boundary Exchange

NASA Technical Reports Server (NTRS)

Hammond, Dana P.

1997-01-01

This paper describes the recognition of implicit serialization due to coarse-grain, synchronous communication and demonstrates the conversion to asynchronous communication for the exchange of boundary condition information in the Thin-Layer Navier Stokes 3-Dimensional Multi Block (TLNS3DMB) code. The implementation details of using asynchronous communication is provided including buffer allocation, message identification, and barrier control. The IBM SP2 was used for the tests presented.

Cross-modal face recognition using multi-matcher face scores

NASA Astrophysics Data System (ADS)

Zheng, Yufeng; Blasch, Erik

2015-05-01

The performance of face recognition can be improved using information fusion of multimodal images and/or multiple algorithms. When multimodal face images are available, cross-modal recognition is meaningful for security and surveillance applications. For example, a probe face is a thermal image (especially at nighttime), while only visible face images are available in the gallery database. Matching a thermal probe face onto the visible gallery faces requires crossmodal matching approaches. A few such studies were implemented in facial feature space with medium recognition performance. In this paper, we propose a cross-modal recognition approach, where multimodal faces are cross-matched in feature space and the recognition performance is enhanced with stereo fusion at image, feature and/or score level. In the proposed scenario, there are two cameras for stereo imaging, two face imagers (visible and thermal images) in each camera, and three recognition algorithms (circular Gaussian filter, face pattern byte, linear discriminant analysis). A score vector is formed with three cross-matched face scores from the aforementioned three algorithms. A classifier (e.g., k-nearest neighbor, support vector machine, binomial logical regression [BLR]) is trained then tested with the score vectors by using 10-fold cross validations. The proposed approach was validated with a multispectral stereo face dataset from 105 subjects. Our experiments show very promising results: ACR (accuracy rate) = 97.84%, FAR (false accept rate) = 0.84% when cross-matching the fused thermal faces onto the fused visible faces by using three face scores and the BLR classifier.

Development of the Ability to Foresee Consequences of Inept Communications.

ERIC Educational Resources Information Center

Johnson, Russell; And Others

This study is an initial investigation of the effects of grade level, item content and type of probe on children's understanding of communicative ineptness. It was hypothesized that children's recognition and avoidance of inept communications would increase as a function of age and that recognition of ineptness would precede the ability to avoid…

The integration of familiarity and recollection information in short-term recognition: modeling speed-accuracy trade-off functions.

PubMed

Göthe, Katrin; Oberauer, Klaus

2008-05-01

Dual process models postulate familiarity and recollection as the basis of the recognition process. We investigated the time-course of integration of the two information sources to one recognition judgment in a working memory task. We tested 24 subjects with a response signal variant of the modified Sternberg recognition task (Oberauer, 2001) to isolate the time course of three different probe types indicating different combinations of familiarity and source information. We compared two mathematical models implementing different ways of integrating familiarity and recollection. Within each model, we tested three assumptions about the nature of the familiarity signal, with familiarity having (a) only positive values, indicating similarity of the probe with the memory list, (b) only negative values, indicating novelty, or (c) both positive and negative values. Both models provided good fits to the data. A model combining the outputs of both processes additively (Integration Model) gave an overall better fit to the data than a model based on a continuous familiarity signal and a probabilistic all-or-none recollection process (Dominance Model).

Face recognition from unconstrained three-dimensional face images using multitask sparse representation

NASA Astrophysics Data System (ADS)

Bentaieb, Samia; Ouamri, Abdelaziz; Nait-Ali, Amine; Keche, Mokhtar

2018-01-01

We propose and evaluate a three-dimensional (3D) face recognition approach that applies the speeded up robust feature (SURF) algorithm to the depth representation of shape index map, under real-world conditions, using only a single gallery sample for each subject. First, the 3D scans are preprocessed, then SURF is applied on the shape index map to find interest points and their descriptors. Each 3D face scan is represented by keypoints descriptors, and a large dictionary is built from all the gallery descriptors. At the recognition step, descriptors of a probe face scan are sparsely represented by the dictionary. A multitask sparse representation classification is used to determine the identity of each probe face. The feasibility of the approach that uses the SURF algorithm on the shape index map for face identification/authentication is checked through an experimental investigation conducted on Bosphorus, University of Milano Bicocca, and CASIA 3D datasets. It achieves an overall rank one recognition rate of 97.75%, 80.85%, and 95.12%, respectively, on these datasets.

The cognitive architecture for chaining of two mental operations.

PubMed

Sackur, Jérôme; Dehaene, Stanislas

2009-05-01

A simple view, which dates back to Turing, proposes that complex cognitive operations are composed of serially arranged elementary operations, each passing intermediate results to the next. However, whether and how such serial processing is achieved with a brain composed of massively parallel processors, remains an open question. Here, we study the cognitive architecture for chained operations with an elementary arithmetic algorithm: we required participants to add (or subtract) two to a digit, and then compare the result with five. In four experiments, we probed the internal implementation of this task with chronometric analysis, the cued-response method, the priming method, and a subliminal forced-choice procedure. We found evidence for an approximately sequential processing, with an important qualification: the second operation in the algorithm appears to start before completion of the first operation. Furthermore, initially the second operation takes as input the stimulus number rather than the output of the first operation. Thus, operations that should be processed serially are in fact executed partially in parallel. Furthermore, although each elementary operation can proceed subliminally, their chaining does not occur in the absence of conscious perception. Overall, the results suggest that chaining is slow, effortful, imperfect (resulting partly in parallel rather than serial execution) and dependent on conscious control.

Expanding Functionality of Commercial Optical Coherence Tomography Systems by Integrating a Custom Endoscope

PubMed Central

Welge, Weston A.; Barton, Jennifer K.

2015-01-01

Optical coherence tomography (OCT) is a useful imaging modality for detecting and monitoring diseases of the gastrointestinal tract and other tubular structures. The non-destructiveness of OCT enables time-serial studies in animal models. While turnkey commercial research OCT systems are plenty, researchers often require custom imaging probes. We describe the integration of a custom endoscope with a commercial swept-source OCT system and generalize this description to any imaging probe and OCT system. A numerical dispersion compensation method is also described. Example images demonstrate that OCT can visualize the mouse colon crypt structure and detect adenoma in vivo. PMID:26418811

Sticky-flares for in situ monitoring of human telomerase RNA in living cells.

PubMed

Wu, Qilong; Liu, Zhengjie; Su, Lei; Han, Guangmei; Liu, Renyong; Zhao, Jun; Zhao, Tingting; Jiang, Changlong; Zhang, Zhongping

2018-05-17

Human telomerase RNA (hTR), a template of telomerase for telomeric repeat synthesis, was used to reflect the telomerase activity and act as a potential target of antitumor therapy. Here, we report a novel DNA-conjugated AuNP probe termed sticky-flares for the in situ detection of intracellular human telomerase RNA. The sticky-flares probe is capable of entering living cells directly without any auxiliary and recognizing the binding domain of human telomerase RNA. On recognition, the fluorophore-modified recognition flares can specifically bind to the target, separate from the sticky-flares and act as a fluorescent reporter to quantify and dynamically profile human telomerase RNA in living cells. We envision that the sticky-flares probe would be a valuable platform to investigate the function and regulation of hTR in antitumor therapy and hTR-related drug invention.

Type-specific proactive interference in patients with semantic and phonological STM deficits.

PubMed

Harris, Lara; Olson, Andrew; Humphreys, Glyn

2014-01-01

Prior neuropsychological evidence suggests that semantic and phonological components of short-term memory (STM) are functionally and neurologically distinct. The current paper examines proactive interference (PI) from semantic and phonological information in two STM-impaired patients, DS (semantic STM deficit) and AK (phonological STM deficit). In Experiment 1 probe recognition tasks with open and closed sets of stimuli were used. Phonological PI was assessed using nonword items, and semantic and phonological PI was assessed using words. In Experiment 2 phonological and semantic PI was elicited by an item recognition probe test with stimuli that bore phonological and semantic relations to the probes. The data suggested heightened phonological PI for the semantic STM patient, and exaggerated effects of semantic PI in the phonological STM case. The findings are consistent with an account of extremely rapid decay of activated type-specific representations in cases of severely impaired phonological and semantic STM.

Ultrasensitive detection of Ag(I) based on the conformational switching of a multifunctional aptamer probe induced by silver(I)

NASA Astrophysics Data System (ADS)

Zhu, Yu-Feng; Wang, Yong-Sheng; Zhou, Bin; Huang, Yan-Qin; Li, Xue-Jiao; Chen, Si-Han; Wang, Xiao-Feng; Tang, Xian

2018-01-01

We for the first time confirmed that the low concentrations of Ag(I) could induce a silver specific aptamer probe (SAP) from a random coil sequence form to G-quadruplex structure. Thereby, a novel highly sensitive fluorescence strategy for silver(I) assay was established. The designed multifunctional SAP could act as a recognition element for Ag(I) and a signal reporter. The use of such a SAP can ultrasensitively and selectively detect Ag(I), giving a detection limit down to 0.64 nM. This is much lower than those reported by related literatures. This strategy has been applied successfully for the detection of Ag(I) in real samples, further proving its reliability. Taken together, the designed SAP is not only a useful recognition and signal probe for silver, but also gives a platform to study the interaction of monovalent cations with DNA.

Detection of protease and protease activity using a single nanoscrescent SERS probe

DOEpatents

Liu, Gang L.; Ellman, Jonathan A.; Lee, Luke P.; Chen, Fanqing Frank

2013-01-29

This invention pertains to the in vitro detection of proteases using a single peptide-conjugate nanocrescent surface enhanced Raman scattering (SERS) probes with at least nanomolar sensitivity. The probe enables detection of proteolytic activity in extremely small volume and at low concentration. In certain embodiments the probes comprise an indicator for the detection of an active protease, where the indicator comprises a nanocrescent attached to a peptide, where said peptide comprises a recognition site for the protease and a Raman tag attached to the peptide.

Detection of protease and protease activity using a single nanocrescent SERS probe

DOEpatents

Liu, Gang L.; Ellman, Jonathan A.; Lee, Luke P.; Chen, Fanqing Frank

2015-09-29

This invention pertains to the in vitro detection of proteases using a single peptide-conjugate nanocrescent surface enhanced Raman scattering (SERS) probes with at least nanomolar sensitivity. The probe enables detection of proteolytic activity in extremely small volume and at low concentration. In certain embodiments the probes comprise an indicator for the detection of an active protease, where the indicator comprises a nanocrescent attached to a peptide, where said peptide comprises a recognition site for the protease and a Raman tag attached to the peptide.

Development of Fluorescent Protein Probes Specific for Parallel DNA and RNA G-Quadruplexes.

PubMed

Dang, Dung Thanh; Phan, Anh Tuân

2016-01-01

We have developed fluorescent protein probes specific for parallel G-quadruplexes by attaching cyan fluorescent protein to the G-quadruplex-binding motif of the RNA helicase RHAU. Fluorescent probes containing RHAU peptide fragments of different lengths were constructed, and their binding to G-quadruplexes was characterized. The selective recognition and discrimination of G-quadruplex topologies by the fluorescent protein probes was easily detected by the naked eye or by conventional gel imaging. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mind wandering in text comprehension under dual-task conditions.

PubMed

Dixon, Peter; Li, Henry

2013-01-01

In two experiments, subjects responded to on-task probes while reading under dual-task conditions. The secondary task was to monitor the text for occurrences of the letter e. In Experiment 1, reading comprehension was assessed with a multiple-choice recognition test; in Experiment 2, subjects recalled the text. In both experiments, the secondary task replicated the well-known "missing-letter effect" in which detection of e's was less effective for function words and the word "the." Letter detection was also more effective when subjects were on task, but this effect did not interact with the missing-letter effect. Comprehension was assessed in both the dual-task conditions and in control single-task conditions. In the single-task conditions, both recognition (Experiment 1) and recall (Experiment 2) was better when subjects were on task, replicating previous research on mind wandering. Surprisingly, though, comprehension under dual-task conditions only showed an effect of being on task when measured with recall; there was no effect on recognition performance. Our interpretation of this pattern of results is that subjects generate responses to on-task probes on the basis of a retrospective assessment of the contents of working memory. Further, we argue that under dual-task conditions, the contents of working memory is not closely related to the reading processes required for accurate recognition performance. These conclusions have implications for models of text comprehension and for the interpretation of on-task probe responses.

Mind wandering in text comprehension under dual-task conditions

PubMed Central

Dixon, Peter; Li, Henry

2013-01-01

In two experiments, subjects responded to on-task probes while reading under dual-task conditions. The secondary task was to monitor the text for occurrences of the letter e. In Experiment 1, reading comprehension was assessed with a multiple-choice recognition test; in Experiment 2, subjects recalled the text. In both experiments, the secondary task replicated the well-known “missing-letter effect” in which detection of e's was less effective for function words and the word “the.” Letter detection was also more effective when subjects were on task, but this effect did not interact with the missing-letter effect. Comprehension was assessed in both the dual-task conditions and in control single-task conditions. In the single-task conditions, both recognition (Experiment 1) and recall (Experiment 2) was better when subjects were on task, replicating previous research on mind wandering. Surprisingly, though, comprehension under dual-task conditions only showed an effect of being on task when measured with recall; there was no effect on recognition performance. Our interpretation of this pattern of results is that subjects generate responses to on-task probes on the basis of a retrospective assessment of the contents of working memory. Further, we argue that under dual-task conditions, the contents of working memory is not closely related to the reading processes required for accurate recognition performance. These conclusions have implications for models of text comprehension and for the interpretation of on-task probe responses. PMID:24101909

Recognition of oral spelling is diagnostic of the central reading processes.

PubMed

Schubert, Teresa; McCloskey, Michael

2015-01-01

The task of recognition of oral spelling (stimulus: "C-A-T", response: "cat") is often administered to individuals with acquired written language disorders, yet there is no consensus about the underlying cognitive processes. We adjudicate between two existing hypotheses: Recognition of oral spelling uses central reading processes, or recognition of oral spelling uses central spelling processes in reverse. We tested the recognition of oral spelling and spelling to dictation abilities of a single individual with acquired dyslexia and dysgraphia. She was impaired relative to matched controls in spelling to dictation but unimpaired in recognition of oral spelling. Recognition of oral spelling for exception words (e.g., colonel) and pronounceable nonwords (e.g., larth) was intact. Our results were predicted by the hypothesis that recognition of oral spelling involves the central reading processes. We conclude that recognition of oral spelling is a useful tool for probing the integrity of the central reading processes.

Detection of active decay at groundline in utility poles

Treesearch

Alex L. Shigo; Walter C. Shortle; Julian Ochrymowych

1977-01-01

Active wood decay at groundline in in-service utility poles can be detected by a skilled inspector using: 1. A knowledge of basic patterns of decay. 2. Recognition of obvious signs of decay. 3. Proper interpretation of information obtained from a pulsed-current meter-Shigometer®-used with various probes and probing techniques.

Novel rhodamine Schiff base type naked-eye fluorescent probe for sensing Fe3 + and the application in cell

NASA Astrophysics Data System (ADS)

Chen, Xia; Sun, Wei; Bai, Yinjuan; Zhang, Feifei; Zhao, Junxia; Ding, Xiaohu

2018-02-01

Three rhodamine schiff-base type fluorescent sensors R1-R3 for detecting iron ion (Fe3 +), 2-furanacrolein rhodamine hydrazone (R1), furfural rhodamine hydrazone (R2) and 2-furanacrolein rhodamine ethylenediamine (R3) have been synthesized by using rhodamine B derivatives and furan derivatives as staring materials. And their recognition abilities for Fe3 + were studied by fluorescence spectroscopy. The result showed that R1 is a best selective probe for Fe3 + over other metal ions in EtOH/H2O (1:1, v/v) due to having 2-furanacrolein for unique space coordination structural. The recognition of Fe3 + and mechanism of the sensor were characterized and determined by fluorescence spectra and Fukui function. And the fluorescence intensity of the probe R1 for Fe3 + was proportional to its concentration with the linear correlation coefficient of 0.9965 and the binding constant of 7.66 × 104 M- 1. And the cell imaging experiment indicated a successful application of the probe R1 for Fe3 + in living cell.

Upconversion particles coated with molecularly imprinted polymers as fluorescence probe for detection of clenbuterol.

PubMed

Tang, Yiwei; Gao, Ziyuan; Wang, Shuo; Gao, Xue; Gao, Jingwen; Ma, Yong; Liu, Xiuying; Li, Jianrong

2015-09-15

A novel fluorescence probe based on upconversion particles, YF3:Yb(3+), Er(3+), coating with molecularly imprinted polymers (MIPs@UCPs) has been synthesized for selective recognition of the analyte clenbuterol (CLB), which was characterized by scan electron microscope and X-ray powder diffraction. The fluorescence of the MIPs@UCPs probe is quenched specifically by CLB, and the effect is much stronger than the NIPs@UCPs (non-imprinting polymers, NIPs). Good linear correlation was obtained for CLB over the concentration range of 5.0-100.0 μg L(-1) with a detection limit of 0.12 μg L(-1) (S/N=3). The developed method was also used in the determination of CLB in water and pork samples, and the recoveries ranged from 81.66% to 102.46% were obtained with relative standard deviation of 2.96-4.98% (n=3). The present study provides a new and general tactics to synthesize MIPs@UCPs fluorescence probe with highly selective recognition ability to the CLB and is desirable for application widely in the near future. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultrafast all-optical imaging technique using low-temperature grown GaAs/AlxGa1 - xAs multiple-quantum-well semiconductor

NASA Astrophysics Data System (ADS)

Gao, Guilong; Tian, Jinshou; Wang, Tao; He, Kai; Zhang, Chunmin; Zhang, Jun; Chen, Shaorong; Jia, Hui; Yuan, Fenfang; Liang, Lingliang; Yan, Xin; Li, Shaohui; Wang, Chao; Yin, Fei

2017-11-01

We report and experimentally demonstrate an ultrafast all-optical imaging technique capable of single-shot ultrafast recording with a picosecond-scale temporal resolution and a micron-order two-dimensional spatial resolution. A GaAs/AlxGa1 - xAs multiple-quantum-well (MQW) semiconductor with a picosecond response time, grown using molecular beam epitaxy (MBE) at a low temperature (LT), is used for the first time in ultrafast imaging technology. The semiconductor transforms the signal beam information to the probe beam, the birefringent delay crystal time-serializes the input probe beam, and the beam displacer maps different polarization probe beams onto different detector locations, resulting in two frames with an approximately 9 ps temporal separation and approximately 25 lp/mm spatial resolution in the visible range.

Study on recognition algorithm for paper currency numbers based on neural network

NASA Astrophysics Data System (ADS)

Li, Xiuyan; Liu, Tiegen; Li, Yuanyao; Zhang, Zhongchuan; Deng, Shichao

2008-12-01

Based on the unique characteristic, the paper currency numbers can be put into record and the automatic identification equipment for paper currency numbers is supplied to currency circulation market in order to provide convenience for financial sectors to trace the fiduciary circulation socially and provide effective supervision on paper currency. Simultaneously it is favorable for identifying forged notes, blacklisting the forged notes numbers and solving the major social problems, such as armor cash carrier robbery, money laundering. For the purpose of recognizing the paper currency numbers, a recognition algorithm based on neural network is presented in the paper. Number lines in original paper currency images can be draw out through image processing, such as image de-noising, skew correction, segmentation, and image normalization. According to the different characteristics between digits and letters in serial number, two kinds of classifiers are designed. With the characteristics of associative memory, optimization-compute and rapid convergence, the Discrete Hopfield Neural Network (DHNN) is utilized to recognize the letters; with the characteristics of simple structure, quick learning and global optimum, the Radial-Basis Function Neural Network (RBFNN) is adopted to identify the digits. Then the final recognition results are obtained by combining the two kinds of recognition results in regular sequence. Through the simulation tests, it is confirmed by simulation results that the recognition algorithm of combination of two kinds of recognition methods has such advantages as high recognition rate and faster recognition simultaneously, which is worthy of broad application prospect.

A novel fluorescein-based "turn-on" probe for the detection of hydrazine and its application in living cells

NASA Astrophysics Data System (ADS)

Xu, Wen-Zhi; Liu, Wei-Yan; Zhou, Ting-Ting; Yang, Yu-Tao; Li, Wei

2018-03-01

We constructed a novel probe for hydrazine detection based on ICT and PET mechanism. Phthalimide and acetyl ester groups were used as the recognition units. Addition of hydrazine produced a turn-on fluorescence at 525 nm along with the fluorescent color change from dark to yellow. The probe could selectively detect hydrazine over other related interfering species. The detection limit of the probe for hydrazine was calculated to be 0.057 μM which was lower than the EPA standard (0.320 μM). Furthermore, the probe could also be applied for the imaging of hydrazine in living cells.

Direct Sequence Detection of Structured H5 Influenza Viral RNA

PubMed Central

Kerby, Matthew B.; Freeman, Sarah; Prachanronarong, Kristina; Artenstein, Andrew W.; Opal, Steven M.; Tripathi, Anubhav

2008-01-01

We describe the development of sequence-specific molecular beacons (dual-labeled DNA probes) for identification of the H5 influenza subtype, cleavage motif, and receptor specificity when hybridized directly with in vitro transcribed viral RNA (vRNA). The cloned hemagglutinin segment from a highly pathogenic H5N1 strain, A/Hanoi/30408/2005(H5N1), isolated from humans was used as template for in vitro transcription of sense-strand vRNA. The hybridization behavior of vRNA and a conserved subtype probe was characterized experimentally by varying conditions of time, temperature, and Mg2+ to optimize detection. Comparison of the hybridization rates of probe to DNA and RNA targets indicates that conformational switching of influenza RNA structure is a rate-limiting step and that the secondary structure of vRNA dominates the binding kinetics. The sensitivity and specificity of probe recognition of other H5 strains was calculated from sequence matches to the National Center for Biotechnology Information influenza database. The hybridization specificity of the subtype probes was experimentally verified with point mutations within the probe loop at five locations corresponding to the other human H5 strains. The abundance frequencies of the hemagglutinin cleavage motif and sialic acid recognition sequences were experimentally tested for H5 in all host viral species. Although the detection assay must be coupled with isothermal amplification on the chip, the new probes form the basis of a portable point-of-care diagnostic device for influenza subtyping. PMID:18403607

Proactive Interference Slows Recognition by Eliminating Fast Assessments of Familiarity

ERIC Educational Resources Information Center

Oztekin, Ilke; McElree, Brian

2007-01-01

The response-signal speed-accuracy tradeoff (SAT) procedure was used to investigate how proactive interference (PI) affects retrieval from working memory. Participants were presented with 6-item study lists, followed immediately by a recognition probe. A variant of a release from PI design was used: All items in a list were from the same semantic…

Development of Functional Fluorescent Molecular Probes for the Detection of Biological Substances

PubMed Central

Suzuki, Yoshio; Yokoyama, Kenji

2015-01-01

This review is confined to sensors that use fluorescence to transmit biochemical information. Fluorescence is, by far, the most frequently exploited phenomenon for chemical sensors and biosensors. Parameters that define the application of such sensors include intensity, decay time, anisotropy, quenching efficiency, and luminescence energy transfer. To achieve selective (bio)molecular recognition based on these fluorescence phenomena, various fluorescent elements such as small organic molecules, enzymes, antibodies, and oligonucleotides have been designed and synthesized over the past decades. This review describes the immense variety of fluorescent probes that have been designed for the recognitions of ions, small and large molecules, and their biological applications in terms of intracellular fluorescent imaging techniques. PMID:26095660

Liquid sample delivery techniques for serial femtosecond crystallography

PubMed Central

Weierstall, Uwe

2014-01-01

X-ray free-electron lasers overcome the problem of radiation damage in protein crystallography and allow structure determination from micro- and nanocrystals at room temperature. To ensure that consecutive X-ray pulses do not probe previously exposed crystals, the sample needs to be replaced with the X-ray repetition rate, which ranges from 120 Hz at warm linac-based free-electron lasers to 1 MHz at superconducting linacs. Liquid injectors are therefore an essential part of a serial femtosecond crystallography experiment at an X-ray free-electron laser. Here, we compare different techniques of injecting microcrystals in solution into the pulsed X-ray beam in vacuum. Sample waste due to mismatch of the liquid flow rate to the X-ray repetition rate can be addressed through various techniques. PMID:24914163

Is scanning in probed order recall articulatory?

PubMed

Farrell, Simon; Lelièvre, Anna

2009-09-01

We consider how theories of serial recall might apply to other short-term memory tasks involving recall of order. In particular, we consider the possibility that when participants are cued to recall an item at an arbitrary position in a sequence, they covertly serially recall the list up to the cued position. One question is whether such "scanning" is articulatory in nature. Two experiments are presented in which the syllabic length of words preceding and following target positions were manipulated, to test the prediction of an articulatory-based mechanism that time to recall an item at a particular position will depend on the number of preceding long words. Although latency was dependent on target position, no word length effects on latency were observed. Additionally, the effects of word length on accuracy replicate recent demonstrations in serial recall that recall accuracy is dependent on the word length of all list items, not just that of target items, in line with distinctiveness assumptions. It is concluded that if scanning does occur, it is not carried out by covert or overt articulation.

Review: Serial Femtosecond Crystallography: A Revolution in Structural Biology

PubMed Central

Martin-Garcia, Jose M.; Conrad, Chelsie E.; Coe, Jesse; Roy-Chowdhury, Shatabdi; Fromme, Petra

2016-01-01

Macromolecular crystallography at synchrotron sources has proven to be the most influential method within structural biology, producing thousands of structures since its inception. While its utility has been instrumental in progressing our knowledge of structures of molecules, it suffers from limitations such as the need for large, well-diffracting crystals, and radiation damage that can hamper native structural determination. The recent advent of X-ray free electron lasers (XFELs) and their implementation in the emerging field of serial femtosecond crystallography (SFX) has given rise to a remarkable expansion upon existing crystallographic constraints, allowing structural biologists access to previously restricted scientific territory. SFX relies on exceptionally brilliant, micro-focused X-ray pulses, which are femtoseconds in duration, to probe nano/micrometer sized crystals in a serial fashion. This results in data sets comprised of individual snapshots, each capturing Bragg diffraction of single crystals in random orientations prior to their subsequent destruction. Thus structural elucidation while avoiding radiation damage, even at room temperature, can now be achieved. This emerging field has cultivated new methods for nanocrystallogenesis, sample delivery, and data processing. Opportunities and challenges within SFX are reviewed herein. PMID:27143509

Serial femtosecond crystallography: A revolution in structural biology.

PubMed

Martin-Garcia, Jose M; Conrad, Chelsie E; Coe, Jesse; Roy-Chowdhury, Shatabdi; Fromme, Petra

2016-07-15

Macromolecular crystallography at synchrotron sources has proven to be the most influential method within structural biology, producing thousands of structures since its inception. While its utility has been instrumental in progressing our knowledge of structures of molecules, it suffers from limitations such as the need for large, well-diffracting crystals, and radiation damage that can hamper native structural determination. The recent advent of X-ray free electron lasers (XFELs) and their implementation in the emerging field of serial femtosecond crystallography (SFX) has given rise to a remarkable expansion upon existing crystallographic constraints, allowing structural biologists access to previously restricted scientific territory. SFX relies on exceptionally brilliant, micro-focused X-ray pulses, which are femtoseconds in duration, to probe nano/micrometer sized crystals in a serial fashion. This results in data sets comprised of individual snapshots, each capturing Bragg diffraction of single crystals in random orientations prior to their subsequent destruction. Thus structural elucidation while avoiding radiation damage, even at room temperature, can now be achieved. This emerging field has cultivated new methods for nanocrystallogenesis, sample delivery, and data processing. Opportunities and challenges within SFX are reviewed herein. Published by Elsevier Inc.

Stimulus and Response-Locked P3 Activity in a Dynamic Rapid Serial Visual Presentation (RSVP) Task

DTIC Science & Technology

2013-01-01

Perception and Psychophysics 1973, 14, 265–272. Touryan, J.; Gibson, L.; Horne, J. H.; Weber, P. Real-Time Classification of Neural Signals ...execution. 15. SUBJECT TERMS P300, RSVP, EEG, target recognition, reaction time, ERP 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT...applications and as an input signal in many brain computer interactive technologies (BCITs) for both patients and healthy individuals. ERPs are extracted

A host-guest-recognition-based electrochemical aptasensor for thrombin detection.

PubMed

Fan, Hao; Li, Hui; Wang, Qingjiang; He, Pingang; Fang, Yuzhi

2012-05-15

A sensitive electrochemical aptasensor for thrombin detection is presented based on the host-guest recognition technique. In this sensing protocol, a 15 based thrombin aptamer (ab. TBA) was dually labeled with a thiol at its 3' end and a 4-((4-(dimethylamino)phenyl)azo) benzoic acid (dabcyl) at its 5' end, respectively, which was previously immobilized on one Au electrode surface by AuS bond and used as the thrombin probe during the protein sensing procedure. One special electrochemical marker was prepared by modifying CdS nanoparticle with β-cyclodextrins (ab. CdS-CDs), which employed as electrochemical signal provider and would conjunct with the thrombin probe modified electrode through the host-guest recognition of CDs to dabcyl. In the absence of thrombin, the probe adopted linear structure to conjunct with CdS-CDs. In present of thrombin, the TBA bond with thrombin and transformed into its special G-quarter structure, which forced CdS-CDs into the solution. Therefore, the target-TBA binding event can be sensitively transduced via detecting the electrochemical oxidation current signal of Cd of CdS nanoparticles in the solution. Using this method, as low as 4.6 pM thrombin had been detected. Copyright © 2012 Elsevier B.V. All rights reserved.

A near-infrared fluorescent probe for rapid detection of carbon monoxide in living cells.

PubMed

Yan, Liqiang; Nan, Ding; Lin, Cheng; Wan, Yi; Pan, Qiang; Qi, Zhengjian

2018-09-05

A near-infrared (NIR) and colorimetric fluorescent probe system was developed for Carbon Monoxide (CO) via a Pd 0 -mediated Tsuji-Trost reaction. In this probe, phenoxide anion formation (DPCO - ) was acted as the signal unit and an allyl carbonate group was used as the recognition unit. This non-fluorescent probe molecule can release the relevant fluorophore after conversion of Pd 2+ to Pd 0 by CO. The probe system including probe 1 and Pd 2+ can be used for "naked-eye" detection of CO, and exhibited high selectivity to CO over various other sensing objects. More importantly, the probe system has great potential for fluorescence imaging of intracellular CO in living cells. Copyright © 2018 Elsevier B.V. All rights reserved.

Metabolite profiling with HPLC-ICP-MS as a tool for in vivo characterization of imaging probes.

PubMed

Boros, Eszter; Pinkhasov, Omar R; Caravan, Peter

2018-01-01

Current analytical methods for characterizing pharmacokinetic and metabolic properties of positron emission tomography (PET) and single photon emission computed tomography (SPECT) probes are limited. Alternative methods to study tracer metabolism are needed. The study objective was to assess the potential of high performance liquid chromatography - inductively coupled plasma - mass spectrometry (HPLC-ICP-MS) for quantification of molecular probe metabolism and pharmacokinetics using stable isotopes. Two known peptide-DOTA conjugates were chelated with nat Ga and nat In. Limit of detection of HPLC-ICP-MS for 69 Ga and 115 In was determined. Rats were administered 50-150 nmol of Ga- and/or In-labeled probes, blood was serially sampled, and plasma analyzed by HPLC-ICP-MS using both reverse phase and size exclusion chromatography. The limits of detection were 0.16 pmol for 115 In and 0.53 pmol for 69 Ga. Metabolites as low as 0.001 %ID/g could be detected and transchelation products identified. Simultaneous administration of Ga- and In-labeled probes allowed the determination of pharmacokinetics and metabolism of both probes in a single animal. HPLC-ICP-MS is a robust, sensitive and radiation-free technique to characterize the pharmacokinetics and metabolism of imaging probes.

Nomenclature of Vertebral Laminae in Lizards, with Comments on Ontogenetic and Serial Variation in Lacertini (Squamata, Lacertidae)

PubMed Central

Tschopp, Emanuel

2016-01-01

Vertebral laminae are bony ridges or sheets that connect important morphological landmarks on the vertebrae, like diapophyses or zygapophyses. They usually exhibit some serial variation throughout the column. A consistent terminology facilitates the morphological description of this variation, and the recognition of patterns that could be taxonomically significant and could serve as phylogenetic characters. Such a terminology was designed for saurischian dinosaurs, and has also been applied to other members of Archosauriformes. Herein, this terminology is applied for the first time to lizards (Squamata). Probably due to their generally smaller size compared to saurischian dinosaurs, lizards have less developed vertebral laminae. Some laminae could not be recognized in this group and others require new names to account for differences in basic vertebral morphology. For instance, the fusion of diapophysis and parapophysis in lacertids into a structure called synapophysis necessitates the creation of the new term synapophyseal laminae for both diapophyseal and parapophyseal laminae. An assessment of occurrence and serial variation in a number of lacertid species shows that some laminae develop throughout ontogeny or only occur in large-sized species, whereas the distribution of other laminae might prove to be taxonomically significant in future. PMID:26907769

Nomenclature of Vertebral Laminae in Lizards, with Comments on Ontogenetic and Serial Variation in Lacertini (Squamata, Lacertidae).

PubMed

Tschopp, Emanuel

2016-01-01

Vertebral laminae are bony ridges or sheets that connect important morphological landmarks on the vertebrae, like diapophyses or zygapophyses. They usually exhibit some serial variation throughout the column. A consistent terminology facilitates the morphological description of this variation, and the recognition of patterns that could be taxonomically significant and could serve as phylogenetic characters. Such a terminology was designed for saurischian dinosaurs, and has also been applied to other members of Archosauriformes. Herein, this terminology is applied for the first time to lizards (Squamata). Probably due to their generally smaller size compared to saurischian dinosaurs, lizards have less developed vertebral laminae. Some laminae could not be recognized in this group and others require new names to account for differences in basic vertebral morphology. For instance, the fusion of diapophysis and parapophysis in lacertids into a structure called synapophysis necessitates the creation of the new term synapophyseal laminae for both diapophyseal and parapophyseal laminae. An assessment of occurrence and serial variation in a number of lacertid species shows that some laminae develop throughout ontogeny or only occur in large-sized species, whereas the distribution of other laminae might prove to be taxonomically significant in future.

Global Similarity Predicts Dissociation of Classification and Recognition: Evidence Questioning the Implicit-Explicit Learning Distinction in Amnesia

ERIC Educational Resources Information Center

Jamieson, Randall K.; Holmes, Signy; Mewhort, D. J. K.

2010-01-01

Dissociation of classification and recognition in amnesia is widely taken to imply 2 functional systems: an implicit procedural-learning system that is spared in amnesia and an explicit episodic-learning system that is compromised. We argue that both tasks reflect the global similarity of probes to memory. In classification, subjects sort…

Relationship between Measures of Working Memory Capacity and the Time Course of Short-Term Memory Retrieval and Interference Resolution

ERIC Educational Resources Information Center

Oztekin, Ilke; McElree, Brian

2010-01-01

The response-signal speed-accuracy trade-off (SAT) procedure was used to investigate the relationship between measures of working memory capacity and the time course of short-term item recognition. High- and low-span participants studied sequentially presented 6-item lists, immediately followed by a recognition probe. Analyses of composite list…

Free recall test experience potentiates strategy-driven effects of value on memory.

PubMed

Cohen, Michael S; Rissman, Jesse; Hovhannisyan, Mariam; Castel, Alan D; Knowlton, Barbara J

2017-10-01

People tend to show better memory for information that is deemed valuable or important. By one mechanism, individuals selectively engage deeper, semantic encoding strategies for high value items (Cohen, Rissman, Suthana, Castel, & Knowlton, 2014). By another mechanism, information paired with value or reward is automatically strengthened in memory via dopaminergic projections from midbrain to hippocampus (Shohamy & Adcock, 2010). We hypothesized that the latter mechanism would primarily enhance recollection-based memory, while the former mechanism would strengthen both recollection and familiarity. We also hypothesized that providing interspersed tests during study is a key to encouraging selective engagement of strategies. To test these hypotheses, we presented participants with sets of words, and each word was associated with a high or low point value. In some experiments, free recall tests were given after each list. In all experiments, a recognition test was administered 5 minutes after the final word list. Process dissociation was accomplished via remember/know judgments at recognition, a recall test probing both item memory and memory for a contextual detail (word plurality), and a task dissociation combining a recognition test for plurality (intended to probe recollection) with a speeded item recognition test (to probe familiarity). When recall tests were administered after study lists, high value strengthened both recollection and familiarity. When memory was not tested after each study list, but rather only at the end, value increased recollection but not familiarity. These dual process dissociations suggest that interspersed recall tests guide learners' use of metacognitive control to selectively apply effective encoding strategies. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

The aftermath of memory retrieval for recycling visual working memory representations.

PubMed

Park, Hyung-Bum; Zhang, Weiwei; Hyun, Joo-Seok

2017-07-01

We examined the aftermath of accessing and retrieving a subset of information stored in visual working memory (VWM)-namely, whether detection of a mismatch between memory and perception can impair the original memory of an item while triggering recognition-induced forgetting for the remaining, untested items. For this purpose, we devised a consecutive-change detection task wherein two successive testing probes were displayed after a single set of memory items. Across two experiments utilizing different memory-testing methods (whole vs. single probe), we observed a reliable pattern of poor performance in change detection for the second test when the first test had exhibited a color change. The impairment after a color change was evident even when the same memory item was repeatedly probed; this suggests that an attention-driven, salient visual change made it difficult to reinstate the previously remembered item. The second change detection, for memory items untested during the first change detection, was also found to be inaccurate, indicating that recognition-induced forgetting had occurred for the unprobed items in VWM. In a third experiment, we conducted a task that involved change detection plus continuous recall, wherein a memory recall task was presented after the change detection task. The analyses of the distributions of recall errors with a probabilistic mixture model revealed that the memory impairments from both visual changes and recognition-induced forgetting are explained better by the stochastic loss of memory items than by their degraded resolution. These results indicate that attention-driven visual change and recognition-induced forgetting jointly influence the "recycling" of VWM representations.

The cortisol awakening response is associated with performance of a serial sequence reaction time task.

PubMed

Hodyl, Nicolette A; Schneider, Luke; Vallence, Ann-Maree; Clow, Angela; Ridding, Michael C; Pitcher, Julia B

2016-02-01

There is emerging evidence of a relationship between the cortisol awakening response (CAR) and the neural mechanisms underlying learning and memory. The aim of this study was to determine whether the CAR is associated with acquisition, retention and overnight consolidation or improvement of a serial sequence reaction time task. Salivary samples were collected at 0, 15, 30 and 45 min after awakening in 39 healthy adults on 2 consecutive days. The serial sequence reaction time task was repeated each afternoon. Participants completed the perceived stress scale and provided salivary samples prior to testing for cortisol assessment. While the magnitude of the CAR (Z score) was not associated with either baseline performance or the timed improvement during task acquisition of the serial sequence task, a positive correlation was observed with reaction times during the stable performance phase on day 1 (r=0.373, p=0.019). Residuals derived from the relationship between baseline and stable phase reaction times on day 1 were used as a surrogate for the degree of learning: these residuals were also correlated with the CAR mean increase on day 1 (r=0.357, p=0.048). Task performance on day 2 was not associated with the CAR obtained on this same day. No association was observed between the perceived stress score, cortisol at testing or task performance. These data indicate that a smaller CAR in healthy adults is associated with a greater degree of learning and faster performance of a serial sequence reaction time task. These results support recognition of the CAR as an important factor contributing to cognitive performance throughout the day. Copyright © 2015 Elsevier B.V. All rights reserved.

Magnetostriction measurement by four probe method

NASA Astrophysics Data System (ADS)

Dange, S. N.; Radha, S.

2018-04-01

The present paper describes the design and setting up of an indigenouslydevelopedmagnetostriction(MS) measurement setup using four probe method atroom temperature.A standard strain gauge is pasted with a special glue on the sample and its change in resistance with applied magnetic field is measured using KeithleyNanovoltmeter and Current source. An electromagnet with field upto 1.2 tesla is used to source the magnetic field. The sample is placed between the magnet poles using self designed and developed wooden probe stand, capable of moving in three mutually perpendicular directions. The nanovoltmeter and current source are interfaced with PC using RS232 serial interface. A software has been developed in for logging and processing of data. Proper optimization of measurement has been done through software to reduce the noise due to thermal emf and electromagnetic induction. The data acquired for some standard magnetic samples are presented. The sensitivity of the setup is 1microstrain with an error in measurement upto 5%.

Rapid cognitive screening in multiple sclerosis accomplished by the Free Recall and Recognition Test.

PubMed

Claesson, I M; Ytterberg, C; Johansson, S; Almkvist, O; von Koch, L

2007-03-01

This study sought to investigate the feasibility of the Free Recall and Recognition Test (FRRT) as a practical screening tool for cognitive impairment in multiple sclerosis (MS). Persons with MS (n = 227) were consecutively recruited and assessed with four cognitive tests; FRRT, Symbol Digit Modalities Test (SDMT), Paced Auditory Serial Addition Test (PASAT), and the Mini-Mental State Examination (MMSE). Disease severity was assessed by the Expanded Disability Status Scale (EDSS). The FRRT, which was completed by 99% of the cohort in approximately 5 minutes per assessment, correlated significantly with the other cognitive tests, as well as with the disease severity rating. A cut-off of 4 for the FRRT recall rendered 90% sensitivity and 25% specificity, and a cut-off of 4.2 for the FRRT recognition resulted in 70% sensitivity and 51% specificity. We conclude that the FRRT proved feasible as a practical screening tool for cognitive impairment in MS within a clinical setting.

The N400 as a snapshot of interactive processing: evidence from regression analyses of orthographic neighbor and lexical associate effects

PubMed Central

Laszlo, Sarah; Federmeier, Kara D.

2010-01-01

Linking print with meaning tends to be divided into subprocesses, such as recognition of an input's lexical entry and subsequent access of semantics. However, recent results suggest that the set of semantic features activated by an input is broader than implied by a view wherein access serially follows recognition. EEG was collected from participants who viewed items varying in number and frequency of both orthographic neighbors and lexical associates. Regression analysis of single item ERPs replicated past findings, showing that N400 amplitudes are greater for items with more neighbors, and further revealed that N400 amplitudes increase for items with more lexical associates and with higher frequency neighbors or associates. Together, the data suggest that in the N400 time window semantic features of items broadly related to inputs are active, consistent with models in which semantic access takes place in parallel with stimulus recognition. PMID:20624252

Expert decision-making strategies

NASA Technical Reports Server (NTRS)

Mosier, Kathleen L.

1991-01-01

A recognition-primed decisions (RPD) model is employed as a framework to investigate crew decision-making processes. The quality of information transfer, a critical component of the team RPD model and an indicator of the team's 'collective consciouness', is measured and analyzed with repect to crew performance. As indicated by the RPD model, timing and patterns of information search transfer were expected to reflect extensive and continual situation assessment, and serial evaluation of alternative states of the world or decision response options.

Structural Basis of Specific Recognition of Non-Reducing Terminal N-Acetylglucosamine by an Agrocybe aegerita Lectin

PubMed Central

Ren, Xiao-Ming; Li, De-Feng; Jiang, Shuai; Lan, Xian-Qing; Hu, Yonglin; Sun, Hui; Wang, Da-Cheng

2015-01-01

O-linked N-acetylglucosaminylation (O-GlcNAcylation) is a reversible post-translational modification that plays essential roles in many cellular pathways. Research in this field, however, is hampered by the lack of suitable probes to identify, accumulate, and purify the O-GlcNAcylated proteins. We have previously reported the identification of a lectin from the mushroom Agrocybe aegerita, i.e., Agrocybe aegerita lectin 2, or AAL2, that could bind terminal N-acetylglucosamine with higher affinities and specificity than other currently used probes. In this paper, we report the crystal structures of AAL2 and its complexes with GlcNAc and GlcNAcβ1-3Galβ1-4GlcNAc and reveal the structural basis of GlcNAc recognition by AAL2 and residues essential for the binding of terminal N-acetylglucosamine. Study on AAL2 may enable us to design a protein probe that can be used to identify and purify O-GlcNAcylated proteins more efficiently. PMID:26114302

Simultaneous detection of multiple DNA targets by integrating dual-color graphene quantum dot nanoprobes and carbon nanotubes.

PubMed

Qian, Zhaosheng; Shan, Xiaoyue; Chai, Lujing; Chen, Jianrong; Feng, Hui

2014-12-01

Simultaneous detection of multiple DNA targets was achieved based on a biocompatible graphene quantum dots (GQDs) and carbon nanotubes (CNTs) platform through spontaneous assembly between dual-color GQD-based probes and CNTs and subsequently self-recognition between DNA probes and targets. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Probing binding hot spots at protein-RNA recognition sites.

PubMed

Barik, Amita; Nithin, Chandran; Karampudi, Naga Bhushana Rao; Mukherjee, Sunandan; Bahadur, Ranjit Prasad

2016-01-29

We use evolutionary conservation derived from structure alignment of polypeptide sequences along with structural and physicochemical attributes of protein-RNA interfaces to probe the binding hot spots at protein-RNA recognition sites. We find that the degree of conservation varies across the RNA binding proteins; some evolve rapidly compared to others. Additionally, irrespective of the structural class of the complexes, residues at the RNA binding sites are evolutionary better conserved than those at the solvent exposed surfaces. For recognitions involving duplex RNA, residues interacting with the major groove are better conserved than those interacting with the minor groove. We identify multi-interface residues participating simultaneously in protein-protein and protein-RNA interfaces in complexes where more than one polypeptide is involved in RNA recognition, and show that they are better conserved compared to any other RNA binding residues. We find that the residues at water preservation site are better conserved than those at hydrated or at dehydrated sites. Finally, we develop a Random Forests model using structural and physicochemical attributes for predicting binding hot spots. The model accurately predicts 80% of the instances of experimental ΔΔG values in a particular class, and provides a stepping-stone towards the engineering of protein-RNA recognition sites with desired affinity. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Design of a sensitive aptasensor based on magnetic microbeads-assisted strand displacement amplification and target recycling.

PubMed

Li, Ying; Ji, Xiaoting; Song, Weiling; Guo, Yingshu

2013-04-03

A cross-circular amplification system for sensitive detection of adenosine triphosphate (ATP) in cancer cells was developed based on aptamer-target interaction, magnetic microbeads (MBs)-assisted strand displacement amplification and target recycling. Here we described a new recognition probe possessing two parts, the ATP aptamer and the extension part. The recognition probe was firstly immobilized on the surface of MBs and hybridized with its complementary sequence to form a duplex. When combined with ATP, the probe changed its conformation, revealing the extension part in single-strand form, which further served as a toehold for subsequent target recycling. The released complementary sequence of the probe acted as the catalyst of the MB-assisted strand displacement reaction. Incorporated with target recycling, a large amount of biotin-tagged MB complexes were formed to stimulate the generation of chemiluminescence (CL) signal in the presence of luminol and H2O2 by incorporating with streptavidin-HRP, reaching a detection limit of ATP as low as 6.1×10(-10)M. Moreover, sample assays of ATP in Ramos Burkitt's lymphoma B cells were performed, which confirmed the reliability and practicality of the protocol. Copyright © 2013 Elsevier B.V. All rights reserved.

A functional glycoprotein competitive recognition and signal amplification strategy for carbohydrate-protein interaction profiling and cell surface carbohydrate expression evaluation

NASA Astrophysics Data System (ADS)

Wang, Yangzhong; Chen, Zhuhai; Liu, Yang; Li, Jinghong

2013-07-01

A simple and sensitive carbohydrate biosensor has been suggested as a potential tool for accurate analysis of cell surface carbohydrate expression as well as carbohydrate-based therapeutics for a variety of diseases and infections. In this work, a sensitive biosensor for carbohydrate-lectin profiling and in situ cell surface carbohydrate expression was designed by taking advantage of a functional glycoprotein of glucose oxidase acting as both a multivalent recognition unit and a signal amplification probe. Combining the gold nanoparticle catalyzed luminol electrogenerated chemiluminescence and nanocarrier for active biomolecules, the number of cell surface carbohydrate groups could be conveniently read out. The apparent dissociation constant between GOx@Au probes and Con A was detected to be 1.64 nM and was approximately 5 orders of magnitude smaller than that of mannose and Con A, which would arise from the multivalent effect between the probe and Con A. Both glycoproteins and gold nanoparticles contribute to the high affinity between carbohydrates and lectin. The as-proposed biosensor exhibits excellent analytical performance towards the cytosensing of K562 cells with a detection limit of 18 cells, and the mannose moieties on a single K562 cell were determined to be 1.8 × 1010. The biosensor can also act as a useful tool for antibacterial drug screening and mechanism investigation. This strategy integrates the excellent biocompatibility and multivalent recognition of glycoproteins as well as the significant enzymatic catalysis and gold nanoparticle signal amplification, and avoids the cell pretreatment and labelling process. This would contribute to the glycomic analysis and the understanding of complex native glycan-related biological processes.A simple and sensitive carbohydrate biosensor has been suggested as a potential tool for accurate analysis of cell surface carbohydrate expression as well as carbohydrate-based therapeutics for a variety of diseases and infections. In this work, a sensitive biosensor for carbohydrate-lectin profiling and in situ cell surface carbohydrate expression was designed by taking advantage of a functional glycoprotein of glucose oxidase acting as both a multivalent recognition unit and a signal amplification probe. Combining the gold nanoparticle catalyzed luminol electrogenerated chemiluminescence and nanocarrier for active biomolecules, the number of cell surface carbohydrate groups could be conveniently read out. The apparent dissociation constant between GOx@Au probes and Con A was detected to be 1.64 nM and was approximately 5 orders of magnitude smaller than that of mannose and Con A, which would arise from the multivalent effect between the probe and Con A. Both glycoproteins and gold nanoparticles contribute to the high affinity between carbohydrates and lectin. The as-proposed biosensor exhibits excellent analytical performance towards the cytosensing of K562 cells with a detection limit of 18 cells, and the mannose moieties on a single K562 cell were determined to be 1.8 × 1010. The biosensor can also act as a useful tool for antibacterial drug screening and mechanism investigation. This strategy integrates the excellent biocompatibility and multivalent recognition of glycoproteins as well as the significant enzymatic catalysis and gold nanoparticle signal amplification, and avoids the cell pretreatment and labelling process. This would contribute to the glycomic analysis and the understanding of complex native glycan-related biological processes. Electronic supplementary information (ESI) available: Experimental details; characterization of probes; the influence of electrolyte pH; probe concentration and glucose concentration on the electrode ECL effect. See DOI: 10.1039/c3nr01598j

Fuel cell CO sensor

DOEpatents

Grot, Stephen Andreas; Meltser, Mark Alexander; Gutowski, Stanley; Neutzler, Jay Kevin; Borup, Rodney Lynn; Weisbrod, Kirk

1999-12-14

The CO concentration in the H.sub.2 feed stream to a PEM fuel cell stack is monitored by measuring current and/or voltage behavior patterns from a PEM-probe communicating with the reformate feed stream. Pattern recognition software may be used to compare the current and voltage patterns from the PEM-probe to current and voltage telltale outputs determined from a reference cell similar to the PEM-probe and operated under controlled conditions over a wide range of CO concentrations in the H.sub.2 fuel stream. A CO sensor includes the PEM-probe, an electrical discharge circuit for discharging the PEM-probe to monitor the CO concentration, and an electrical purging circuit to intermittently raise the anode potential of the PEM-probe's anode to at least about 0.8 V (RHE) to electrochemically oxidize any CO adsorbed on the probe's anode catalyst.

Method of monitoring CO concentrations in hydrogen feed to a PEM fuel cell

DOEpatents

Grot, Stephen Andreas; Meltser, Mark Alexander; Gutowski, Stanley; Neutzler, Jay Kevin; Borup, Rodney Lynn; Weisbrod, Kirk

2000-01-01

The CO concentration in the H.sub.2 feed stream to a PEM fuel cell stack is monitored by measuring current and/or voltage behavior patterns from a PEM-probe communicating with the reformate feed stream. Pattern recognition software may be used to compare the current and voltage patterns from the PEM-probe to current and voltage telltale outputs determined from a reference cell similar to the PEM-probe and operated under controlled conditions over a wide range of CO concentrations in the H.sub.2 fuel stream. The PEM-probe is intermittently purged of any CO build-up on the anode catalyst (e.g., by (1) flushing the anode with air, (2) short circuiting the PEM-probe, or (3) reverse biasing the PEM-probe) to keep the PEM-probe at peak performance levels.

A reagent for specific recognition of cysteine in aqueous buffer and in natural milk: imaging studies, enzymatic reaction and analysis of whey protein.

PubMed

A, Anila H; G, Upendar Reddy; Ali, Firoj; Taye, Nandaraj; Chattopadhyay, Samit; Das, Amitava

2015-11-04

We report a new chemodosimetric probe () for specific recognition of cysteine (Cys) in aqueous buffer and in whey protein isolated from fresh cow's milk. Using this reagent we could develop a luminescence-based methodology for estimation of Cys released from a commercially available Cys-supplement drug by aminoacylase-1 in live cells.

Visualization of nucleic acids with synthetic exciton-controlled fluorescent oligonucleotide probes.

PubMed

Wang, Dan Ohtan; Okamoto, Akimitsu

2015-01-01

Engineered probes to adapt new photochemical properties upon recognition of target nucleic acids offer powerful tools to DNA and RNA visualization technologies. Herein, we describe a rapid and effective visualization method of nucleic acids in both fixed and living cells with hybridization-sensitive fluorescent oligonucleotide probes. These probes are efficiently quenched in an aqueous environment due to the homodimeric, excitonic interactions between fluorophores but become highly fluorescent upon hybridization to DNA or RNA with complementary sequences. The fast hybridization kinetics and quick fluorescence activation of the new probes allow applications to simplify the conventional fluorescent in situ hybridization protocols and reduce the amount of time to process the samples. Furthermore, hybridization-sensitive fluorescence emission of the probes allows monitoring dynamic behaviors of RNA in living cells.

Studies on the formation and stability of triplex DNA using fluorescence correlation spectroscopy.

PubMed

Hu, Hongyan; Huang, Xiangyi; Ren, Jicun

2016-05-01

Triplex DNA has become one of the most useful recognition motifs in the design of new molecular biology tools, therapeutic agents and sophisticated DNA-based nanomaterials because of its direct recognition of natural double-stranded DNA. In this paper, we developed a sensitive and microscale method to study the formation and stability characterization of triplex DNA using fluorescence correlation spectroscopy (FCS). The principle of this method is mainly based on the excellent capacity of FCS for sensitively distinguishing between free single-strand DNA (ssDNA) fluorescent probes and fluorescent probe-double-strand DNA (dsDNA) hybridized complexes. First, we systematically investigated the experimental conditions of triplex DNA formation. Then, we evaluated the equilibrium association constants (K(a)) under different ssDNA probe lengths, composition and pH. Finally, we used FCS to measure the hybridization fraction of a 20-mer perfectly matched ssDNA probe and three single-base mismatched ssDNA probes with 146-mer dsDNA. Our data illustrated that FCS is a useful tool for the direct determination of the thermodynamic parameters of triplex DNA formation and discrimination of a single-base mismatch of triplex DNA without denaturation. Compared with current methods, our method is characterized by high sensitivity, good universality and small sample and reagent requirements. More importantly, our method has the potential to become a platform for triplex DNA research in vitro. Copyright © 2015 John Wiley & Sons, Ltd.

Fluorescent and colorimetric molecular recognition probe for hydrogen bond acceptors.

PubMed

Pike, Sarah J; Hunter, Christopher A

2017-11-22

The association constants for formation of 1 : 1 complexes between a H-bond donor, 1-naphthol, and a diverse range of charged and neutral H-bond acceptors have been measured using UV/vis absorption and fluorescence emission titrations. The performance of 1-naphthol as a dual colorimetric and fluorescent molecular recognition probe for determining the H-bond acceptor (HBA) parameters of charged and neutral solutes has been investigated in three solvents. The data were employed to establish self-consistent H-bond acceptor parameters (β) for benzoate, azide, chloride, thiocyanate anions, a series of phosphine oxides, phosphate ester, sulfoxide and a tertiary amide. The results demonstrate both the transferability of H-bond parameters between different solvents and the utility of the naphthol-based dual molecular recognition probe to exploit orthogonal spectroscopic techniques to determine the HBA properties of neutral and charged solutes. The benzoate anion is the strongest HBA studied with a β parameter of 15.4, and the neutral tertiary amide is the weakest H-bond acceptor investigated with a β parameter of 8.5. The H-bond acceptor strength of the azide anion is higher than that of chloride (12.8 and 12.2 respectively), and the thiocyanate anion has a β value of 10.8 and thus is a significantly weaker H-bond acceptor than both the azide and chloride anions.

"Off-On"switching electrochemiluminescence biosensor for mercury(II) detection based on molecular recognition technology.

PubMed

Cheng, Lin; Wei, BingGuo; He, Ling Ling; Mao, Ling; Zhang, Jie; Ceng, JinXiang; Kong, DeRong; Chen, ChaDan; Cui, HanFeng; Hong, Nian; Fan, Hao

2017-02-01

A novel "off-On" electrogenerated chemiluminescence (ECL) biosensor has been developed for the detection of mercury(II) based on molecular recognition technology. The ECL mercury(II) biosensor comprises two main parts: an ECL substrate and an ECL intensity switch. The ECL substrate was made by modifying the complex of Ruthenium(II) tris-(bipyridine)(Ru(bpy) 3 2+ )/Cyclodextrins-Au nanoparticles(CD-AuNps)/Nafion on the surface of glass carbon electrode (GCE), and the ECL intensity switch is the single hairpin DNA probe designed according to the "molecular recognition" strategy which was functionalized with ferrocene tag at one end and attached to Cyclodextrins (CD) on modified GCE through supramolecular noncovalent interaction. We demonstrated that, in the absence of Hg(II) ion, the probe keeps single hairpin structure and resulted in a quenching of ECL of Ru(bpy) 3 2+ . Whereas, in the presence of Hg(II) ion, the probe prefers to form the T-Hg(II)-T complex and lead to an obvious recovery of ECL of Ru(bpy) 3 2+ , which provided a sensing platform for the detection of Hg(II) ion. Using this sensing platform, a simple, rapid and selective "off-On" ECL biosensor for the detection of mercury(II) with a detection limit of 0.1 nM has been developed. Copyright © 2016. Published by Elsevier Inc.

Selective attention to emotional cues and emotion recognition in healthy subjects: the role of mineralocorticoid receptor stimulation.

PubMed

Schultebraucks, Katharina; Deuter, Christian E; Duesenberg, Moritz; Schulze, Lars; Hellmann-Regen, Julian; Domke, Antonia; Lockenvitz, Lisa; Kuehl, Linn K; Otte, Christian; Wingenfeld, Katja

2016-09-01

Selective attention toward emotional cues and emotion recognition of facial expressions are important aspects of social cognition. Stress modulates social cognition through cortisol, which acts on glucocorticoid (GR) and mineralocorticoid receptors (MR) in the brain. We examined the role of MR activation on attentional bias toward emotional cues and on emotion recognition. We included 40 healthy young women and 40 healthy young men (mean age 23.9 ± 3.3), who either received 0.4 mg of the MR agonist fludrocortisone or placebo. A dot-probe paradigm was used to test for attentional biases toward emotional cues (happy and sad faces). Moreover, we used a facial emotion recognition task to investigate the ability to recognize emotional valence (anger and sadness) from facial expression in four graded categories of emotional intensity (20, 30, 40, and 80 %). In the emotional dot-probe task, we found a main effect of treatment and a treatment × valence interaction. Post hoc analyses revealed an attentional bias away from sad faces after placebo intake and a shift in selective attention toward sad faces compared to placebo. We found no attentional bias toward happy faces after fludrocortisone or placebo intake. In the facial emotion recognition task, there was no main effect of treatment. MR stimulation seems to be important in modulating quick, automatic emotional processing, i.e., a shift in selective attention toward negative emotional cues. Our results confirm and extend previous findings of MR function. However, we did not find an effect of MR stimulation on emotion recognition.

Some-or-none recollection: Evidence from item and source memory.

PubMed

Onyper, Serge V; Zhang, Yaofei X; Howard, Marc W

2010-05-01

Dual-process theory hypothesizes that recognition memory depends on 2 distinguishable memory signals. Recollection reflects conscious recovery of detailed information about the learning episode. Familiarity reflects a memory signal that is not accompanied by a vivid conscious experience but nonetheless enables participants to distinguish recently experienced probe items from novel ones. This dual-process explanation of recognition memory has gained wide acceptance among cognitive neuroscientists and some cognitive psychologists. Nonetheless, its difficulty in providing a quantitatively satisfactory description of performance has precluded a consensus not only regarding the theoretical structure of recognition memory but also about how to best measure recognition accuracy. In 2 experiments we show that neither the standard formulation of dual-process signal detection (DPSD) theory nor a widely used single-process model called the unequal-variance signal-detection (UVSD) model provides a satisfactory explanation of recognition memory across different types of stimuli (words and travel scenes). In the variable-recollection dual-process (VRDP) model, recollection fails for some old probe items, as in standard formulations of DPSD, but gives rise to a continuous distribution of memory strengths when it succeeds. The VRDP can approximate both the DPSD and UVSD. In both experiments it provides a consistently superior fit across materials to the superset of the DPSD and UVSD. The VRDP offers a simple explanation of the form of conjoint item-source judgments, something neither the DPSD nor UVSD accomplishes. The success of the VRDP supports the core assumptions of dual-process theory by providing an excellent quantitative description of recognition performance across materials and response criteria.

Pose-Invariant Face Recognition via RGB-D Images.

PubMed

Sang, Gaoli; Li, Jing; Zhao, Qijun

2016-01-01

Three-dimensional (3D) face models can intrinsically handle large pose face recognition problem. In this paper, we propose a novel pose-invariant face recognition method via RGB-D images. By employing depth, our method is able to handle self-occlusion and deformation, both of which are challenging problems in two-dimensional (2D) face recognition. Texture images in the gallery can be rendered to the same view as the probe via depth. Meanwhile, depth is also used for similarity measure via frontalization and symmetric filling. Finally, both texture and depth contribute to the final identity estimation. Experiments on Bosphorus, CurtinFaces, Eurecom, and Kiwi databases demonstrate that the additional depth information has improved the performance of face recognition with large pose variations and under even more challenging conditions.

Serial Femtosecond Crystallography and Ultrafast Absorption Spectroscopy of the Photoswitchable Fluorescent Protein IrisFP.

PubMed

Colletier, Jacques-Philippe; Sliwa, Michel; Gallat, François-Xavier; Sugahara, Michihiro; Guillon, Virginia; Schirò, Giorgio; Coquelle, Nicolas; Woodhouse, Joyce; Roux, Laure; Gotthard, Guillaume; Royant, Antoine; Uriarte, Lucas Martinez; Ruckebusch, Cyril; Joti, Yasumasa; Byrdin, Martin; Mizohata, Eiichi; Nango, Eriko; Tanaka, Tomoyuki; Tono, Kensuke; Yabashi, Makina; Adam, Virgile; Cammarata, Marco; Schlichting, Ilme; Bourgeois, Dominique; Weik, Martin

2016-03-03

Reversibly photoswitchable fluorescent proteins find growing applications in cell biology, yet mechanistic details, in particular on the ultrafast photochemical time scale, remain unknown. We employed time-resolved pump-probe absorption spectroscopy on the reversibly photoswitchable fluorescent protein IrisFP in solution to study photoswitching from the nonfluorescent (off) to the fluorescent (on) state. Evidence is provided for the existence of several intermediate states on the pico- and microsecond time scales that are attributed to chromophore isomerization and proton transfer, respectively. Kinetic modeling favors a sequential mechanism with the existence of two excited state intermediates with lifetimes of 2 and 15 ps, the second of which controls the photoswitching quantum yield. In order to support that IrisFP is suited for time-resolved experiments aiming at a structural characterization of these ps intermediates, we used serial femtosecond crystallography at an X-ray free electron laser and solved the structure of IrisFP in its on state. Sample consumption was minimized by embedding crystals in mineral grease, in which they remain photoswitchable. Our spectroscopic and structural results pave the way for time-resolved serial femtosecond crystallography aiming at characterizing the structure of ultrafast intermediates in reversibly photoswitchable fluorescent proteins.

Molecular recognition of a model globular protein apomyoglobin by synthetic receptor cyclodextrin: effect of fluorescence modification of the protein and cavity size of the receptor in the interaction.

PubMed

Saha, Ranajay; Rakshit, Surajit; Pal, Samir Kumar

2013-11-01

Labelling of proteins with some extrinsic probe is unavoidable in molecular biology research. Particularly, spectroscopic studies in the optical region require fluorescence modification of native proteins by attaching polycyclic aromatic fluoroprobe with the proteins under investigation. Our present study aims to address the consequence of the attachment of a fluoroprobe at the protein surface in the molecular recognition of the protein by selectively small model receptor. A spectroscopic study involving apomyoglobin (Apo-Mb) and cyclodextrin (CyD) of various cavity sizes as model globular protein and synthetic receptors, respectively, using steady-state and picosecond-resolved techniques, is detailed here. A study involving Förster resonance energy transfer, between intrinsic amino acid tryptophan (donor) and N, N-dimethyl naphthalene moiety of the extrinsic dansyl probes at the surface of Apo-Mb, precisely monitor changes in donor acceptor distance as a consequence of interaction of the protein with CyD having different cavity sizes (β and γ variety). Molecular modelling studies on the interaction of tryptophan and dansyl probe with β-CyD is reported here and found to be consistent with the experimental observations. In order to investigate structural aspects of the interacting protein, we have used circular dichroism spectroscopy. Temperature-dependent circular dichroism studies explore the change in the secondary structure of Apo-Mb in association with CyD, before and after fluorescence modification of the protein. Overall, the study well exemplifies approaches to protein recognition by CyD as a synthetic receptor and offers a cautionary note on the use of hydrophobic fluorescent labels for proteins in biochemical studies involving recognition of molecules. Copyright © 2013 John Wiley & Sons, Ltd.

The lateral septum and anterior hypothalamus act in tandem to regulate burying in the shock-probe test but not open-arm avoidance in the elevated plus-maze.

PubMed

Lamontagne, Steven J; Olmstead, Mary C; Menard, Janet L

2016-11-01

Both the lateral septum (LS) and anterior hypothalamus (AHA) regulate behavioural defense. We tested whether those two interconnected structures act in serial in that regard. Infusions of the GABAA agonist muscimol into one side of the LS and the contralateral (but not ipsilateral) AHA suppressed rats' burying in the shock-probe test whereas none of our muscimol infusion approaches altered their open-arm avoidance in the elevated plus-maze. These results suggest that the LS-AHA circuit serves a specialized role in defensive responses towards discrete, localizable threat stimuli but not towards potential threats. Copyright © 2016 Elsevier B.V. All rights reserved.

Is Grey Level a Suitable Alternative to Low-Contrast Penetration as a Serial Measure of Sensitivity in Computerised Ultrasound Quality Assurance?

PubMed

Dudley, Nicholas J; Gibson, Nicholas M

2017-02-01

The aim of this study was to test the hypothesis that grey levels are a suitable alternative measure of sensitivity in ultrasound imaging quality assurance, as there are several caveats in the use of penetration depth. In a primary cohort of nine probes, where measurements had been made for 6 to 34 mo, both penetration depth and mean grey level fell below tolerance for six probes; both penetration depth and mean grey level remained within tolerance for three probes. In a secondary cohort where a measurement programme had been in place for a shorter period, grey level and/or penetration depth fell below tolerance in 15 of 66 probes; the sensitivity and specificity of at least 10% loss of grey level in predicting >5% loss in penetration depth were 91% and 93%, respectively. A loss of grey level accompanies a loss of penetration and provides a suitable alternative measure of sensitivity. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

Thioflavin T as an efficient fluorescence sensor for selective recognition of RNA G-quadruplexes

NASA Astrophysics Data System (ADS)

Xu, Shujuan; Li, Qian; Xiang, Junfeng; Yang, Qianfan; Sun, Hongxia; Guan, Aijiao; Wang, Lixia; Liu, Yan; Yu, Lijia; Shi, Yunhua; Chen, Hongbo; Tang, Yalin

2016-04-01

RNA G-quadruplexes (G4s) play important roles in translational regulation, mRNA processing events and gene expression. Therefore, a fluorescent probe that is capable of efficiently recognizing RNA G-quadruplex structures among other RNA forms is highly desirable. In this study, a water-soluble fluorogenic dye (i.e., Thioflavin T (ThT)) was employed to recognize RNA G-quadruplex structures using UV-Vis absorption spectra, fluorescence spectra and emission lifetime experiments. By stacking on the G-tetrad, the ThT probe exhibited highly specific recognition of RNA G-quadruplex structures with striking fluorescence enhancement compared with other RNA forms. The specific binding demonstrates that ThT is an efficient fluorescence sensor that can distinguish G4 and non-G4 RNA structures.

Protein recognition by a pattern-generating fluorescent molecular probe.

PubMed

Pode, Zohar; Peri-Naor, Ronny; Georgeson, Joseph M; Ilani, Tal; Kiss, Vladimir; Unger, Tamar; Markus, Barak; Barr, Haim M; Motiei, Leila; Margulies, David

2017-12-01

Fluorescent molecular probes have become valuable tools in protein research; however, the current methods for using these probes are less suitable for analysing specific populations of proteins in their native environment. In this study, we address this gap by developing a unimolecular fluorescent probe that combines the properties of small-molecule-based probes and cross-reactive sensor arrays (the so-called chemical 'noses/tongues'). On the one hand, the probe can detect different proteins by generating unique identification (ID) patterns, akin to cross-reactive arrays. On the other hand, its unimolecular scaffold and selective binding enable this ID-generating probe to identify combinations of specific protein families within complex mixtures and to discriminate among isoforms in living cells, where macroscopic arrays cannot access. The ability to recycle the molecular device and use it to track several binding interactions simultaneously further demonstrates how this approach could expand the fluorescent toolbox currently used to detect and image proteins.

Protein recognition by a pattern-generating fluorescent molecular probe

NASA Astrophysics Data System (ADS)

Pode, Zohar; Peri-Naor, Ronny; Georgeson, Joseph M.; Ilani, Tal; Kiss, Vladimir; Unger, Tamar; Markus, Barak; Barr, Haim M.; Motiei, Leila; Margulies, David

2017-12-01

Fluorescent molecular probes have become valuable tools in protein research; however, the current methods for using these probes are less suitable for analysing specific populations of proteins in their native environment. In this study, we address this gap by developing a unimolecular fluorescent probe that combines the properties of small-molecule-based probes and cross-reactive sensor arrays (the so-called chemical 'noses/tongues'). On the one hand, the probe can detect different proteins by generating unique identification (ID) patterns, akin to cross-reactive arrays. On the other hand, its unimolecular scaffold and selective binding enable this ID-generating probe to identify combinations of specific protein families within complex mixtures and to discriminate among isoforms in living cells, where macroscopic arrays cannot access. The ability to recycle the molecular device and use it to track several binding interactions simultaneously further demonstrates how this approach could expand the fluorescent toolbox currently used to detect and image proteins.

A ratiometric fluorescent probe for rapid and sensitive detection of biothiols in fetal bovine serum.

PubMed

Wang, Fengyang; Feng, Chongchong; Lu, Linlin; Xu, Zhiai; Zhang, Wen

2017-07-01

Herein, a ratiometric turn-on fluorescent probe for sensitive detection of biothiols was designed. The probe consisted of two parts: one was rhodamine B serving as a fluorescence reference, and the other was coumarin derivative as the responsive fluorophore with an acrylate group for biothiols recognition. The response was based on the mechanism of Michael addition and intramolecular cyclization reaction, and the probe showed ratiometric and sensitive response to biothiols. Especially, the detection limit of this probe for cysteine was found to be 0.13μΜ. More importantly, the probe showed the advantage of fast response, of which the fluorescence intensity can reach the maximum within 10min. The ratiometric fluorescent probe has been successfully applied for the determination of biothiols in fetal bovine serum samples and the result was in good agreement with that tested by Ellman method. Copyright © 2017. Published by Elsevier B.V.

Nonpeptide-Based Small-Molecule Probe for Fluorogenic and Chromogenic Detection of Chymotrypsin.

PubMed

Wu, Lei; Yang, Shu-Hou; Xiong, Hao; Yang, Jia-Qian; Guo, Jun; Yang, Wen-Chao; Yang, Guang-Fu

2017-03-21

We report herein a nonpeptide-based small-molecule probe for fluorogenic and chromogenic detection of chymotrypsin, as well as the primary application for this probe. This probe was rationally designed by mimicking the peptide substrate and optimized by adjusting the recognition group. The refined probe 2 exhibits good specificity toward chymotrypsin, producing about 25-fold higher enhancement in both the fluorescence intensity and absorbance upon the catalysis by chymotrypsin. Compared with the most widely used peptide substrate (AMC-FPAA-Suc) of chymotrypsin, probe 2 shows about 5-fold higher binding affinity and comparable catalytical efficiency against chymotrypsin. Furthermore, it was successfully applied for the inhibitor characterization. To the best of our knowledge, probe 2 is the first nonpeptide-based small-molecule probe for chymotrypsin, with the advantages of simple structure and high sensitivity compared to the widely used peptide-based substrates. This small-molecule probe is expected to be a useful molecular tool for drug discovery and chymotrypsin-related disease diagnosis.

Developing a 3-choice serial reaction time task for examining neural and cognitive function in an equine model.

PubMed

Roberts, Kirsty; Hemmings, Andrew J; McBride, Sebastian D; Parker, Matthew O

2017-12-01

Large animal models of human neurological disorders are advantageous compared to rodent models due to their neuroanatomical complexity, longevity and their ability to be maintained in naturalised environments. Some large animal models spontaneously develop behaviours that closely resemble the symptoms of neural and psychiatric disorders. The horse is an example of this; the domestic form of this species consistently develops spontaneous stereotypic behaviours akin to the compulsive and impulsive behaviours observed in human neurological disorders such as Tourette's syndrome. The ability to non-invasively probe normal and abnormal equine brain function through cognitive testing may provide an extremely useful methodological tool to assess brain changes associated with certain human neurological and psychiatric conditions. An automated operant system with the ability to present visual and auditory stimuli as well as dispense salient food reward was developed. To validate the system, ten horses were trained and tested using a standard cognitive task (three choice serial reaction time task (3-CSRTT)). All animals achieved total learning criterion and performed six probe sessions. Learning criterion was met within 16.30±0.79 sessions over a three day period. During six probe sessions, level of performance was maintained at 80.67±0.57% (mean±SEM) accuracy. This is the first mobile fully automated system developed to examine cognitive function in the horse. A fully-automated operant system for mobile cognitive function of a large animal model has been designed and validated. Horses pose an interesting complementary model to rodents for the examination of human neurological dysfunction. Copyright © 2017 Elsevier B.V. All rights reserved.

A fluorescein-based chemosensor for relay fluorescence recognition of Cu(ii) ions and biothiols in water and its applications to a molecular logic gate and living cell imaging.

PubMed

Fu, Zhen-Hai; Yan, Lu-Bin; Zhang, Xiaolong; Zhu, Fan-Fan; Han, Xin-Long; Fang, Jianguo; Wang, Ya-Wen; Peng, Yu

2017-05-16

Relay recognition of copper(ii) ions and biothiols via a fluorescence "on-off-on" cascade was designed and realized as a new sequential combination of cations and small molecules. Probe 1 bearing a fluorescein skeleton was thus synthesized, which performed well in 100% HEPES buffer (pH = 7.0) solution, as a highly sensitive, selective fluorescence sensor for Cu 2+ . The limit of detection (LOD, 0.017 ppm) was obtained, and this value is much lower than 1.3 ppm, allowed by US EPA. The 1 : 1 complex generated from fast sensing of Cu 2+ when excited at 491 nm, showed good relay recognition for biothiols (i.e., Cys, Hcy and GSH with low detection limits of 0.12 μM, 0.036 μM and 0.024 μM, respectively) via remarkable fluorescence enhancement. The origin of this relay process was disclosed through ESI-MS and corresponding density functional theory (DFT) computations. Notably, probe 1 can be utilized for the construction of a molecular logic gate with the IMPLICATION function by using the above fluorescence changes. Moreover, this relay recognition was also applied to HepG2 cell imaging successfully.

Explicit and spontaneous retrieval of emotional scenes: electrophysiological correlates.

PubMed

Weymar, Mathias; Bradley, Margaret M; El-Hinnawi, Nasryn; Lang, Peter J

2013-10-01

When event-related potentials (ERP) are measured during a recognition task, items that have previously been presented typically elicit a larger late (400-800 ms) positive potential than new items. Recent data, however, suggest that emotional, but not neutral, pictures show ERP evidence of spontaneous retrieval when presented in a free-viewing task (Ferrari, Bradley, Codispoti, Karlsson, & Lang, 2012). In two experiments, we further investigated the brain dynamics of implicit and explicit retrieval. In Experiment 1, brain potentials were measured during a semantic categorization task, which did not explicitly probe episodic memory, but which, like a recognition task, required an active decision and a button press, and were compared to those elicited during recognition and free viewing. Explicit recognition prompted a late enhanced positivity for previously presented, compared with new, pictures regardless of hedonic content. In contrast, only emotional pictures showed an old-new difference when the task did not explicitly probe episodic memory, either when making an active categorization decision regarding picture content, or when simply viewing pictures. In Experiment 2, however, neutral pictures did prompt a significant old-new ERP difference during subsequent free viewing when emotionally arousing pictures were not included in the encoding set. These data suggest that spontaneous retrieval is heightened for salient cues, perhaps reflecting heightened attention and elaborative processing at encoding.

Explicit and spontaneous retrieval of emotional scenes: Electrophysiological correlates

PubMed Central

Weymar, Mathias; Bradley, Margaret M.; El-Hinnawi, Nasryn; Lang, Peter J.

2014-01-01

When event-related potentials are measured during a recognition task, items that have previously been presented typically elicit a larger late (400–800 ms) positive potential than new items. Recent data, however, suggest that emotional, but not neutral, pictures show ERP evidence of spontaneous retrieval when presented in a free-viewing task (Ferrari, Bradley, Codispoti & Lang, 2012). In two experiments, we further investigated the brain dynamics of implicit and explicit retrieval. In Experiment 1, brain potentials were measured during a semantic categorization task, which did not explicitly probe episodic memory, but which, like a recognition task, required an active decision and a button press, and were compared to those elicited during recognition and free viewing. Explicit recognition prompted a late enhanced positivity for previously presented, compared to new, pictures regardless of hedonic content. In contrast, only emotional pictures showed an old-new difference when the task did not explicitly probe episodic memory, either when either making an active categorization decision regarding picture content, or when simply viewing pictures. In Experiment 2, however, neutral pictures did prompt a significant old-new ERP difference during subsequent free viewing when emotionally arousing pictures were not included in the encoding set. These data suggest that spontaneous retrieval is heightened for salient cues, perhaps reflecting heightened attention and elaborative processing at encoding. PMID:23795588

Feasibility of asymmetrical flow field-flow fractionation as a method for detecting protective antigen by direct recognition of size-increased target-captured nanoprobes.

PubMed

Shin, Kayeong; Choi, Jaeyeong; Cho, Jun-Haeng; Yoon, Moon-Young; Lee, Seungho; Chung, Hoeil

2015-11-27

Asymmetrical flow field-flow fractionation (AF4) was evaluated as a potential analytical method for detection of a protective antigen (PA), an Anthrax biomarker. The scheme was based on the recognition of altered AF4 retention through the generation of the size-increased Au nanoparticle probes as a result of PA binding, in which a PA-selective peptide was conjugated on the probe surface. In the visible absorption-based AF4 fractograms, the band position shifted to a longer retention time as the PA concentration increased due to the presence of probe bound with PAs. The shift was insignificant when the concentration was relatively low at 84.3pM. To improve sensitivity, two separate probes conjugated with two different peptides able to bind on different PA epitopes were used together. The band shift then became distinguishable even at 84.3pM of PA sample. The formation of larger PA-probe inter-connected species using the dual-probe system was responsible for the enhanced band shift. In parallel, the feasibility of surface-enhanced Raman scattering (SERS) as a potential AF4 detection method was also evaluated. In the off-line SERS fractogram constructed using fractions collected during AF4 separation, a band shift was also observed for the 84.3pM PA sample, and the band intensity was higher when using the dual-probe system. The combination of AF4 and SERS is promising for the detection of PA and will become a potential tool if the reproducibility of SERS measurement is improved. Copyright © 2015 Elsevier B.V. All rights reserved.

Nature and extent of person recognition impairments associated with Capgras syndrome in Lewy body dementia

PubMed Central

Fiacconi, Chris M.; Barkley, Victoria; Finger, Elizabeth C.; Carson, Nicole; Duke, Devin; Rosenbaum, R. Shayna; Gilboa, Asaf; Köhler, Stefan

2014-01-01

Patients with Capgras syndrome (CS) adopt the delusional belief that persons well-known to them have been replaced by an imposter. Several current theoretical models of CS attribute such misidentification problems to deficits in covert recognition processes related to the generation of appropriate affective autonomic signals. These models assume intact overt recognition processes for the imposter and, more broadly, for other individuals. As such, it has been suggested that CS could reflect the “mirror-image” of prosopagnosia. The purpose of the current study was to determine whether overt person recognition abilities are indeed always spared in CS. Furthermore, we examined whether CS might be associated with any impairments in overt affective judgments of facial expressions. We pursued these goals by studying a patient with Dementia with Lewy bodies (DLB) who showed clear signs of CS, and by comparing him to another patient with DLB who did not experience CS, as well as to a group of healthy control participants. Clinical magnetic resonance imaging scans revealed medial prefrontal cortex (mPFC) atrophy that appeared to be uniquely associated with the presence CS. We assessed overt person recognition with three fame recognition tasks, using faces, voices, and names as cues. We also included measures of confidence and probed pertinent semantic knowledge. In addition, participants rated the intensity of fearful facial expressions. We found that CS was associated with overt person recognition deficits when probed with faces and voices, but not with names. Critically, these deficits were not present in the DLB patient without CS. In addition, CS was associated with impairments in overt judgments of affect intensity. Taken together, our findings cast doubt on the traditional view that CS is the mirror-image of prosopagnosia and that it spares overt recognition abilities. These findings can still be accommodated by models of CS that emphasize deficits in autonomic responding, to the extent that the potential role of interoceptive awareness in overt judgments is taken into account. PMID:25309399

Memory Asymmetry of Forward and Backward Associations in Recognition Tasks

PubMed Central

Yang, Jiongjiong; Zhu, Zijian; Mecklinger, Axel; Fang, Zhiyong; Li, Han

2013-01-01

There is an intensive debate on whether memory for serial order is symmetric. The objective of this study was to explore whether associative asymmetry is modulated by memory task (recognition vs. cued recall). Participants were asked to memorize word triples (Experiment 1–2) or pairs (Experiment 3–6) during the study phase. They then recalled the word by a cue during a cued recall task (Experiment 1–4), and judged whether the presented two words were in the same or in a different order compared to the study phase during a recognition task (Experiment 1–6). To control for perceptual matching between the study and test phase, participants were presented with vertical test pairs when they made directional judgment in Experiment 5. In Experiment 6, participants also made associative recognition judgments for word pairs presented at the same or the reversed position. The results showed that forward associations were recalled at similar levels as backward associations, and that the correlations between forward and backward associations were high in the cued recall tasks. On the other hand, the direction of forward associations was recognized more accurately (and more quickly) than backward associations, and their correlations were comparable to the control condition in the recognition tasks. This forward advantage was also obtained for the associative recognition task. Diminishing positional information did not change the pattern of associative asymmetry. These results suggest that associative asymmetry is modulated by cued recall and recognition manipulations, and that direction as a constituent part of a memory trace can facilitate associative memory. PMID:22924326

Functional recognition imaging using artificial neural networks: applications to rapid cellular identification via broadband electromechanical response

NASA Astrophysics Data System (ADS)

Nikiforov, M. P.; Reukov, V. V.; Thompson, G. L.; Vertegel, A. A.; Guo, S.; Kalinin, S. V.; Jesse, S.

2009-10-01

Functional recognition imaging in scanning probe microscopy (SPM) using artificial neural network identification is demonstrated. This approach utilizes statistical analysis of complex SPM responses at a single spatial location to identify the target behavior, which is reminiscent of associative thinking in the human brain, obviating the need for analytical models. We demonstrate, as an example of recognition imaging, rapid identification of cellular organisms using the difference in electromechanical activity over a broad frequency range. Single-pixel identification of model Micrococcus lysodeikticus and Pseudomonas fluorescens bacteria is achieved, demonstrating the viability of the method.

Dissociable neural mechanisms underlying response-based and familiarity-based conflict in working memory.

PubMed

Nelson, James K; Reuter-Lorenz, Patricia A; Sylvester, Ching-Yune C; Jonides, John; Smith, Edward E

2003-09-16

Cognitive control requires the resolution of interference among competing and potentially conflicting representations. Such conflict can emerge at different points between stimulus input and response generation, with the net effect being that of compromising performance. The goal of this article was to dissociate the neural mechanisms underlying different sources of conflict to elucidate the architecture of the neural systems that implement cognitive control. By using functional magnetic resonance imaging and a verbal working memory task (item recognition), we examined brain activity related to two kinds of conflict with comparable behavioral consequences. In a trial of our item-recognition task, participants saw four letters, followed by a retention interval, and a probe letter that did or did not match one of the letters held in working memory (positive probe and negative probe, respectively). On some trials, conflict arose solely because of the current negative probe having a high familiarity, due to its membership in the immediately preceding trial's target set. On other trials, additional conflict arose because of the current negative probe having also been a positive probe on the immediately preceding trial, producing response-level conflict. Consistent with previous work, conflict due to high familiarity was associated with left prefrontal activation, but not with anterior cingulate activation. The response-conflict condition, when compared with high-familiarity conflict trials, was associated with anterior cingulate cortex activation, but with no additional left prefrontal activation. This double dissociation points to differing contributions of specific cortical areas to cognitive control, which are based on the source of conflict.

Trial-to-trial carry-over of item- and relational-information in auditory short-term memory

PubMed Central

Visscher, Kristina M.; Kahana, Michael J.; Sekuler, Robert

2009-01-01

Using a short-term recognition memory task we evaluated the carry-over across trials of two types of auditory information: the characteristics of individual study sounds (item information), and the relationships between the study sounds (relational information). On each trial, subjects heard two successive broadband study sounds and then decided whether a subsequently presented probe sound had been in the study set. On some trials, the probe item's similarity to stimuli presented on the preceding trial was manipulated. This item information interfered with recognition, increasing false alarms from 0.4% to 4.4%. Moreover, the interference was tuned so that only stimuli very similar to each other interfered. On other trials, the relationship among stimuli was manipulated in order to alter the criterion subjects used in making recognition judgments. The effect of this manipulation was confined to the very trial on which the criterion change was generated, and did not affect the subsequent trial. These results demonstrate the existence of a sharply-tuned carry-over of auditory item information, but no carry-over of relational information. PMID:19210080

Investigating biomolecular recognition at the cell surface using atomic force microscopy.

PubMed

Wang, Congzhou; Yadavalli, Vamsi K

2014-05-01

Probing the interaction forces that drive biomolecular recognition on cell surfaces is essential for understanding diverse biological processes. Force spectroscopy has been a widely used dynamic analytical technique, allowing measurement of such interactions at the molecular and cellular level. The capabilities of working under near physiological environments, combined with excellent force and lateral resolution make atomic force microscopy (AFM)-based force spectroscopy a powerful approach to measure biomolecular interaction forces not only on non-biological substrates, but also on soft, dynamic cell surfaces. Over the last few years, AFM-based force spectroscopy has provided biophysical insight into how biomolecules on cell surfaces interact with each other and induce relevant biological processes. In this review, we focus on describing the technique of force spectroscopy using the AFM, specifically in the context of probing cell surfaces. We summarize recent progress in understanding the recognition and interactions between macromolecules that may be found at cell surfaces from a force spectroscopy perspective. We further discuss the challenges and future prospects of the application of this versatile technique. Copyright © 2014 Elsevier Ltd. All rights reserved.

Identification of liver cancer-specific aptamers using whole live cells.

PubMed

Shangguan, Dihua; Meng, Ling; Cao, Zehui Charles; Xiao, Zeyu; Fang, Xiaohong; Li, Ying; Cardona, Diana; Witek, Rafal P; Liu, Chen; Tan, Weihong

2008-02-01

Liver cancer is the third most deadly cancers in the world. Unfortunately, there is no effective treatment. One of the major problems is that most cancers are diagnosed in the later stage, when surgical resection is not feasible. Thus, accurate early diagnosis would significantly improve the clinical outcome of liver cancer. Currently, there are no effective molecular probes to recognize biomarkers that are specific for liver cancer. The objective of our current study is to identify liver cancer cell-specific molecular probes that could be used for liver cancer recognition and diagnosis. We applied a newly developed cell-SELEX (Systematic Evolution of Ligands by EXponential enrichment) method for the generation of molecular probes for specific recognition of liver cancer cells. The cell-SELEX uses whole live cells as targets to select aptamers (designed DNA/RNA) for cell recognition. In generating aptamers for liver cancer recognition, two liver cell lines were used: a liver cancer cell line BNL 1ME A.7R.1 (MEAR) and a noncancer cell line, BNL CL.2 (BNL). Both cell lines were originally derived from Balb/cJ mice. Through multiple rounds of selection using BNL as a control, we have identified a panel of aptamers that specifically recognize the cancer cell line MEAR with Kd in the nanomolar range. We have also demonstrated that some of the selective aptamers could specifically bind liver cancer cells in a mouse model. There are two major new results (compared with our reported cell-SELEX methodology) in addition to the generation of aptamers specifically for liver cancer. The first one is that our current study demonstrates that cell-based aptamer selection can select specific aptamers for multiple cell lines, even for two cell lines with minor differences (MEAR cell is derived from BNL by chemical inducement); and the second result is that cell-SELEX can be used for adhesive cells and thus open the door for solid tumor selection and investigation. The newly generated cancer-specific aptamers hold great promise as molecular probes for cancer early diagnosis and basic mechanism studies.

Selective interactions of trivalent cations Fe³⁺, Al³⁺ and Cr³⁺ turn on fluorescence in a naphthalimide based single molecular probe.

PubMed

Janakipriya, Subramaniyan; Chereddy, Narendra Reddy; Korrapati, Purnasai; Thennarasu, Sathiah; Mandal, Asit Baran

2016-01-15

Synthesis and fluorescence turn-on behavior of a naphthalimide based probe is described. Selective interactions of trivalent cations Fe(3+), Al(3+) or Cr(3+) with probe 1 inhibit the PET operating in the probe, and thereby, permit the detection of these trivalent cations present in aqueous samples and live cells. Failure of other trivalent cations (Eu(3+), Gd(3+) and Nb(3+)) to inhibit the PET process in 1 demonstrates the role of chelating ring size vis-à-vis ionic radius in the selective recognition of specific metal ions. Copyright © 2015 Elsevier B.V. All rights reserved.

A new aggregation-induced emission fluorescent probe for rapid detection of nitroreductase and its application in living cells

NASA Astrophysics Data System (ADS)

Xu, Gaoping; Tang, Yonghe; Ma, Yanyan; Xu, An; Lin, Weiying

2018-01-01

The biological activity of nitroreductase (NTR) is closely related to biological hypoxia status in organisms. The development of effective methods for monitoring the activity of NTR is of great significance for medical diagnosis and tumor research. Toward this goal, we have developed a new aggregation-induced emission (AIE) fluorescence NTR probe TPE-HY used the tetraphenylethene as the fluorophore, and used the nitro group as the NTR recognition site. The probe TPE-HY has many excellent properties, including rapid response, AIE characteristics, high sensitivity and selectivity, and low cytotoxicity. Importantly, the probe TPE-HY is successfully applied to monitor endogenous NTR in living HeLa cells.

P3 amplitude attenuation secondary to increases in target-to-target interval (TTI) during spatial serial order recall: Implications for EEG models of working memory function.

PubMed

Hochberger, William C; Axelrod, Jenna L; Sarapas, Casey; Shankman, Stewart A; Hill, S Kristian

2018-06-08

Research suggests that increasing delays in stimulus read-out can trigger declines in serial order recall accuracy due to increases in cognitive demand imposed by the delay; however, the exact neural mechanisms associated with this decline are unclear. Changes in neural resource allocation present as the ideal target and can easily be monitored by examining changes in the amplitude of an ERP component known as the P3. Changes in P3 amplitude secondary to exogenous pacing of stimulus read-out via increased target-to-target intervals (TTI) during recall could reflect decreased neural resource allocation due to increased cognitive demand. This shift in resource allocation could result in working memory storage decay and the declines in serial order accuracy described by prior research. In order to examine this potential effect, participants were administered a spatial serial order processing task, with the recall series consisting of a series of correct ("match") or incorrect ("non-match" or "oddball") stimuli. Moreover, the recall series included either a brief (500ms) or extended (2000ms) delay between stimuli. Results were significant for the presence of a P3 response to non-match stimuli for both experimental conditions, and attenuation of P3 amplitude secondary to the increase in target-to-target interval (TTI). These findings suggest that extending the delay between target recognition could increase cognitive demand and trigger a decrease in neural resource allocation that results in a decay of working memory stores.

Combined experimental and theoretical studies on selective sensing of zinc and pyrophosphate ions by rational design of compartmental chemosensor probe: Dual sensing behaviour via secondary recognition approach and cell imaging studies.

PubMed

Mawai, Kiran; Nathani, Sandip; Roy, Partha; Singh, U P; Ghosh, Kaushik

2018-05-08

A compartmental chemosensor probe HL has been designed and synthesized for the selective recognition of zinc ions over other transition metal ions via fluorescence "ON" strategy. The chemosensing behaviour of HL was demonstrated through fluorescence, absorption and NMR spectroscopic techniques. The molecular structure of the zinc complex derived from HL was determined by X-ray crystallography. A probable mechanism of this selective sensing behavior was described on the basis of spectroscopic results and theoretical studies by density functional theory (DFT). The biological applicability of the chemosensor HL was examined via cell imaging on HeLa cells. The HL-zinc complex served as a secondary fluorescent probe responding to the pyrophosphate anion specifically over other anions. The fluorescence enhancement of HL in association with Zn2+ ions was quenched in the presence of pyrophosphate (PPi). Thus, a dual response was established based on "OFF-ON-OFF" strategy for detection of both cation and anion. This phenomenon was utilized in the construction of a "INHIBIT" logic gate.

Phonological similarity and orthographic similarity affect probed serial recall of Chinese characters.

PubMed

Lin, Yi-Chen; Chen, Hsiang-Yu; Lai, Yvonne C; Wu, Denise H

2015-04-01

The previous literature on working memory (WM) has indicated that verbal materials are dominantly retained in phonological representations, whereas other linguistic information (e.g., orthography, semantics) only contributes to verbal WM minimally, if not negligibly. Although accumulating evidence has suggested that multiple linguistic components jointly support verbal WM, the visual/orthographic contribution has rarely been addressed in alphabetic languages, possibly due to the difficulty of dissociating the effects of word forms from the effects of their pronunciations in relatively shallow orthography. In the present study, we examined whether the orthographic representations of Chinese characters support the retention of verbal materials in this language of deep orthography. In Experiments 1a and 2, we independently manipulated the phonological and orthographic similarity of horizontal and vertical characters, respectively, and found that participants' accuracy of probed serial recall was reduced by both similar pronunciations and shared phonetic radicals in the to-be-remembered stimuli. Moreover, Experiment 1b showed that only the effect of phonological, but not that of orthographic, similarity was affected by concurrent articulatory suppression. Taken together, the present results indicate the indispensable contribution of orthographic representations to verbal WM of Chinese characters, and suggest that the linguistic characteristics of a specific language not only determine long-term linguistic-processing mechanisms, but also delineate the organization of verbal WM for that language.

A Water-Soluble Fluorescent Probe for SO2 Derivatives in Aqueous Solution and Serum Based on Phenanthroimidazole Dye.

PubMed

Zhou, Yang; Wang, Ying; Xiao, Shuzhang; He, Xiafeng; Zhang, Nuonuo; Li, Dejiang; Zheng, Kaibo

2017-05-01

A water-soluble fluorescent SO 2 derivatives probe PI-SO 2 based on a phenanthroimidazole dye, and a sensitive SO 2 recognition site, aldehyde was constructed. The probe PI-SO 2 exhibits desirable properties such as high sensitivity, high selectivity and good water-solubility. Significantly, we have demonstrated that the probe PI-SO 2 is suitable for rapidly fluorescence detecting of SO 2 derivatives in aqueous solution and serum. The application of the novel probe PI-SO 2 proved that it was not only a useful tool for the detection of SO 2 derivatives in vitro, but also a potential assay for investigating the effects of SO 2 derivatives, and demonstrating its value in practical applicationin of complex biological samples.

Room-temperature serial crystallography at synchrotron X-ray sources using slowly flowing free-standing high-viscosity microstreams.

PubMed

Botha, Sabine; Nass, Karol; Barends, Thomas R M; Kabsch, Wolfgang; Latz, Beatrice; Dworkowski, Florian; Foucar, Lutz; Panepucci, Ezequiel; Wang, Meitian; Shoeman, Robert L; Schlichting, Ilme; Doak, R Bruce

2015-02-01

Recent advances in synchrotron sources, beamline optics and detectors are driving a renaissance in room-temperature data collection. The underlying impetus is the recognition that conformational differences are observed in functionally important regions of structures determined using crystals kept at ambient as opposed to cryogenic temperature during data collection. In addition, room-temperature measurements enable time-resolved studies and eliminate the need to find suitable cryoprotectants. Since radiation damage limits the high-resolution data that can be obtained from a single crystal, especially at room temperature, data are typically collected in a serial fashion using a number of crystals to spread the total dose over the entire ensemble. Several approaches have been developed over the years to efficiently exchange crystals for room-temperature data collection. These include in situ collection in trays, chips and capillary mounts. Here, the use of a slowly flowing microscopic stream for crystal delivery is demonstrated, resulting in extremely high-throughput delivery of crystals into the X-ray beam. This free-stream technology, which was originally developed for serial femtosecond crystallography at X-ray free-electron lasers, is here adapted to serial crystallography at synchrotrons. By embedding the crystals in a high-viscosity carrier stream, high-resolution room-temperature studies can be conducted at atmospheric pressure using the unattenuated X-ray beam, thus permitting the analysis of small or weakly scattering crystals. The high-viscosity extrusion injector is described, as is its use to collect high-resolution serial data from native and heavy-atom-derivatized lysozyme crystals at the Swiss Light Source using less than half a milligram of protein crystals. The room-temperature serial data allow de novo structure determination. The crystal size used in this proof-of-principle experiment was dictated by the available flux density. However, upcoming developments in beamline optics, detectors and synchrotron sources will enable the use of true microcrystals. This high-throughput, high-dose-rate methodology provides a new route to investigating the structure and dynamics of macromolecules at ambient temperature.

Facial emotion recognition system for autistic children: a feasible study based on FPGA implementation.

PubMed

Smitha, K G; Vinod, A P

2015-11-01

Children with autism spectrum disorder have difficulty in understanding the emotional and mental states from the facial expressions of the people they interact. The inability to understand other people's emotions will hinder their interpersonal communication. Though many facial emotion recognition algorithms have been proposed in the literature, they are mainly intended for processing by a personal computer, which limits their usability in on-the-move applications where portability is desired. The portability of the system will ensure ease of use and real-time emotion recognition and that will aid for immediate feedback while communicating with caretakers. Principal component analysis (PCA) has been identified as the least complex feature extraction algorithm to be implemented in hardware. In this paper, we present a detailed study of the implementation of serial and parallel implementation of PCA in order to identify the most feasible method for realization of a portable emotion detector for autistic children. The proposed emotion recognizer architectures are implemented on Virtex 7 XC7VX330T FFG1761-3 FPGA. We achieved 82.3% detection accuracy for a word length of 8 bits.

Vander Lugt correlation of DNA sequence data

NASA Astrophysics Data System (ADS)

Christens-Barry, William A.; Hawk, James F.; Martin, James C.

1990-12-01

DNA, the molecule containing the genetic code of an organism, is a linear chain of subunits. It is the sequence of subunits, of which there are four kinds, that constitutes the unique blueprint of an individual. This sequence is the focus of a large number of analyses performed by an army of geneticists, biologists, and computer scientists. Most of these analyses entail searches for specific subsequences within the larger set of sequence data. Thus, most analyses are essentially pattern recognition or correlation tasks. Yet, there are special features to such analysis that influence the strategy and methods of an optical pattern recognition approach. While the serial processing employed in digital electronic computers remains the main engine of sequence analyses, there is no fundamental reason that more efficient parallel methods cannot be used. We describe an approach using optical pattern recognition (OPR) techniques based on matched spatial filtering. This allows parallel comparison of large blocks of sequence data. In this study we have simulated a Vander Lugt1 architecture implementing our approach. Searches for specific target sequence strings within a block of DNA sequence from the Co/El plasmid2 are performed.

Theoretical and Experimental: The Synthetic and Anion-Binding Properties of Tripodal Salicylaldehyde Derivatives.

PubMed

Xu, Zhong-Jie; Zhang, Li-Rong

2016-05-19

A series of colorimetric anion probes 1-6 containing OH and NO₂ groups were synthesized, and their recognition properties toward various anions were investigated by visual observation, ultraviolet-visible spectroscopy, fluorescence, ¹H nuclear magnetic resonance titration spectra and theoretical investigation. Nanomaterials of three compounds 2-4 were prepared successfully. Four compounds 3-6 that contain electron-withdrawing substituents showed a high binding ability for AcO(-). The host-guest complex formed through a 1:1 binding ratio, and color changes were detectable during the recognition process. Theoretical investigation analysis revealed that an intramolecular hydrogen bond existed in the structures of compounds and the roles of molecular frontier orbitals in molecular interplay. These studies suggested that this series of compounds could be used as colorimetric probes to detect of AcO(-).

Evidence for modality-independent order coding in working memory.

PubMed

Depoorter, Ann; Vandierendonck, André

2009-03-01

The aim of the present study was to investigate the representation of serial order in working memory, more specifically whether serial order is coded by means of a modality-dependent or a modality-independent order code. This was investigated by means of a series of four experiments based on a dual-task methodology in which one short-term memory task was embedded between the presentation and recall of another short-term memory task. Two aspects were varied in these memory tasks--namely, the modality of the stimulus materials (verbal or visuo-spatial) and the presence of an order component in the task (an order or an item memory task). The results of this study showed impaired primary-task recognition performance when both the primary and the embedded task included an order component, irrespective of the modality of the stimulus materials. If one or both of the tasks did not contain an order component, less interference was found. The results of this study support the existence of a modality-independent order code.

Validity and Normative Data for the Biber Figure Learning Test: A Visual Supraspan Memory Measure.

PubMed

Gifford, Katherine A; Liu, Dandan; Neal, Jacquelyn E; Acosta, Lealani Mae Y; Bell, Susan P; Wiggins, Margaret E; Wisniewski, Kristi M; Godfrey, Mary; Logan, Laura A; Hohman, Timothy J; Pechman, Kimberly R; Libon, David J; Blennow, Kaj; Zetterberg, Henrik; Jefferson, Angela L

2018-05-01

The Biber Figure Learning Test (BFLT), a visuospatial serial figure learning test, was evaluated for biological correlates and psychometric properties, and normative data were generated. Nondemented individuals ( n = 332, 73 ± 7, 41% female) from the Vanderbilt Memory & Aging Project completed a comprehensive neuropsychological protocol. Adjusted regression models related BFLT indices to structural brain magnetic resonance imaging and cerebrospinal fluid (CSF) markers of brain health. Regression-based normative data were generated. Lower BFLT performances (Total Learning, Delayed Recall, Recognition) related to smaller medial temporal lobe volumes and higher CSF tau concentrations but not CSF amyloid. BFLT indices were most strongly correlated with other measures of verbal and nonverbal memory and visuospatial skills. The BFLT provides a comprehensive assessment of all aspects of visuospatial learning and memory and is sensitive to biomarkers of unhealthy brain aging. Enhanced normative data enriches the clinical utility of this visual serial figure learning test for use with older adults.

Ultra-Rapid serial visual presentation reveals dynamics of feedforward and feedback processes in the ventral visual pathway.

PubMed

Mohsenzadeh, Yalda; Qin, Sheng; Cichy, Radoslaw M; Pantazis, Dimitrios

2018-06-21

Human visual recognition activates a dense network of overlapping feedforward and recurrent neuronal processes, making it hard to disentangle processing in the feedforward from the feedback direction. Here, we used ultra-rapid serial visual presentation to suppress sustained activity that blurs the boundaries of processing steps, enabling us to resolve two distinct stages of processing with MEG multivariate pattern classification. The first processing stage was the rapid activation cascade of the bottom-up sweep, which terminated early as visual stimuli were presented at progressively faster rates. The second stage was the emergence of categorical information with peak latency that shifted later in time with progressively faster stimulus presentations, indexing time-consuming recurrent processing. Using MEG-fMRI fusion with representational similarity, we localized recurrent signals in early visual cortex. Together, our findings segregated an initial bottom-up sweep from subsequent feedback processing, and revealed the neural signature of increased recurrent processing demands for challenging viewing conditions. © 2018, Mohsenzadeh et al.

Stages of processing in associative recognition: evidence from behavior, EEG, and classification.

PubMed

Borst, Jelmer P; Schneider, Darryl W; Walsh, Matthew M; Anderson, John R

2013-12-01

In this study, we investigated the stages of information processing in associative recognition. We recorded EEG data while participants performed an associative recognition task that involved manipulations of word length, associative fan, and probe type, which were hypothesized to affect the perceptual encoding, retrieval, and decision stages of the recognition task, respectively. Analyses of the behavioral and EEG data, supplemented with classification of the EEG data using machine-learning techniques, provided evidence that generally supported the sequence of stages assumed by a computational model developed in the Adaptive Control of Thought-Rational cognitive architecture. However, the results suggested a more complex relationship between memory retrieval and decision-making than assumed by the model. Implications of the results for modeling associative recognition are discussed. The study illustrates how a classifier approach, in combination with focused manipulations, can be used to investigate the timing of processing stages.

Protein crystals as scanned probes for recognition atomic force microscopy.

PubMed

Wickremasinghe, Nissanka S; Hafner, Jason H

2005-12-01

Lysozyme crystal growth has been localized at the tip of a conventional silicon nitride cantilever through seeded nucleation. After cross-linking with glutaraldehyde, lysozyme protein crystal tips image gold nanoparticles and grating standards with a resolution comparable to that of conventional tips. Force spectra between the lysozyme crystal tips and surfaces covered with antilysozyme reveal an adhesion force that drops significantly upon blocking with free lysozyme, thus confirming that lysozyme crystal tips can detect molecular recognition interactions.

An Analysis of Serial Number Tracking Automatic Identification Technology as Used in Naval Aviation Programs

DTIC Science & Technology

2002-09-01

employed by the supermarket industry in 1973. Other common linear bar code symbologies are Code 39, pioneered by the defense and automotive industries...Teller Machine ( ATM ) cards are one of the prominent uses of this technology, but to a lesser extent, the technology has been used for shop floor...additional power is transmitted to it through the probe, extending its charge. There is a risk of data loss if the CMB is not accessed from time to time

Colorimetric detection of mercury ion based on unmodified gold nanoparticles and target-triggered hybridization chain reaction amplification

NASA Astrophysics Data System (ADS)

Wang, Qing; Yang, Xiaohan; Yang, Xiaohai; Liu, Pei; Wang, Kemin; Huang, Jin; Liu, Jianbo; Song, Chunxia; Wang, Jingjing

2015-02-01

A novel unmodified gold nanoparticles (AuNPs)-based colorimetric strategy for label-free, specific and sensitive mercury ion (Hg2+) detection was demonstrated by using thymine-Hg2+-thymine (T-Hg2+-T) recognition mechanism and hybridization chain reaction (HCR) amplification strategy. In this protocol, a structure-switching probe (H0) was designed to recognize Hg2+ and then propagated a chain reaction of hybridization events between two other hairpin probes (H1 and H2). In the absence of Hg2+, all hairpin probes could stably coexist in solution, the exposed sticky ends of hairpin probes were capable of stabilizing AuNPs. As a result, salt-induced AuNPs aggregation could be effectively prevented. In the presence of Hg2+, thymine bases of H0 could specifically interact with Hg2+ to form stable T-Hg2+-T complex. Consequently, the hairpin structure of H0 probe was changed. As H1/H2 probes were added, the HCR process could be triggered and nicked double-helixes were formed. Since it was difficult for the formed nicked double-helixes to inhibit salt-induced AuNPs aggregation, a red-to-blue color change was observed in the colloid solution as the salt concentration increased. With the elegant amplification effect of HCR, a detection limit of around 30 nM was achieved (S/N = 3), which was about 1-2 orders of magnitudes lower than that of previous unmodified AuNPs-based colorimetric methods. By using the T-Hg2+-T recognition mechanism, high selectivity was also obtained. As an unmodified AuNPs-based colorimetric strategy, the system was simple in design, convenient in operation, and eliminated the requirements of separation processes, chemical modifications, and sophisticated instrumentations.

Structural basis for bifunctional peptide recognition at human δ-opioid receptor

DOE PAGES

Fenalti, Gustavo; Zatsepin, Nadia A.; Betti, Cecilia; ...

2015-02-16

Bi-functional μ- and δ- opioid receptor (OR) ligands are potential therapeutic alternatives to alkaloid opiate analgesics with diminished side effects. We solved the structure of human δ-OR bound to the bi-functional δ-OR antagonist and μ-OR agonist tetrapeptide H-Dmt-Tic-Phe-Phe-NH 2 (DIPP-NH 2) by serial femtosecond crystallography, revealing a cis-peptide bond between H-Dmt and Tic. In summary, the observed receptor-peptide interactions are critical to understand the pharmacological profiles of opioid peptides, and to develop improved analgesics.

Learning and Recognition of a Non-conscious Sequence of Events in Human Primary Visual Cortex.

PubMed

Rosenthal, Clive R; Andrews, Samantha K; Antoniades, Chrystalina A; Kennard, Christopher; Soto, David

2016-03-21

Human primary visual cortex (V1) has long been associated with learning simple low-level visual discriminations [1] and is classically considered outside of neural systems that support high-level cognitive behavior in contexts that differ from the original conditions of learning, such as recognition memory [2, 3]. Here, we used a novel fMRI-based dichoptic masking protocol-designed to induce activity in V1, without modulation from visual awareness-to test whether human V1 is implicated in human observers rapidly learning and then later (15-20 min) recognizing a non-conscious and complex (second-order) visuospatial sequence. Learning was associated with a change in V1 activity, as part of a temporo-occipital and basal ganglia network, which is at variance with the cortico-cerebellar network identified in prior studies of "implicit" sequence learning that involved motor responses and visible stimuli (e.g., [4]). Recognition memory was associated with V1 activity, as part of a temporo-occipital network involving the hippocampus, under conditions that were not imputable to mechanisms associated with conscious retrieval. Notably, the V1 responses during learning and recognition separately predicted non-conscious recognition memory, and functional coupling between V1 and the hippocampus was enhanced for old retrieval cues. The results provide a basis for novel hypotheses about the signals that can drive recognition memory, because these data (1) identify human V1 with a memory network that can code complex associative serial visuospatial information and support later non-conscious recognition memory-guided behavior (cf. [5]) and (2) align with mouse models of experience-dependent V1 plasticity in learning and memory [6]. Copyright © 2016 Elsevier Ltd. All rights reserved.

A dynamic model of reasoning and memory.

PubMed

Hawkins, Guy E; Hayes, Brett K; Heit, Evan

2016-02-01

Previous models of category-based induction have neglected how the process of induction unfolds over time. We conceive of induction as a dynamic process and provide the first fine-grained examination of the distribution of response times observed in inductive reasoning. We used these data to develop and empirically test the first major quantitative modeling scheme that simultaneously accounts for inductive decisions and their time course. The model assumes that knowledge of similarity relations among novel test probes and items stored in memory drive an accumulation-to-bound sequential sampling process: Test probes with high similarity to studied exemplars are more likely to trigger a generalization response, and more rapidly, than items with low exemplar similarity. We contrast data and model predictions for inductive decisions with a recognition memory task using a common stimulus set. Hierarchical Bayesian analyses across 2 experiments demonstrated that inductive reasoning and recognition memory primarily differ in the threshold to trigger a decision: Observers required less evidence to make a property generalization judgment (induction) than an identity statement about a previously studied item (recognition). Experiment 1 and a condition emphasizing decision speed in Experiment 2 also found evidence that inductive decisions use lower quality similarity-based information than recognition. The findings suggest that induction might represent a less cautious form of recognition. We conclude that sequential sampling models grounded in exemplar-based similarity, combined with hierarchical Bayesian analysis, provide a more fine-grained and informative analysis of the processes involved in inductive reasoning than is possible solely through examination of choice data. PsycINFO Database Record (c) 2016 APA, all rights reserved.

The NASA Smart Probe Project for real-time multiple microsensor tissue recognition

NASA Technical Reports Server (NTRS)

Andrews, Russell J.; Mah, Robert W.

2003-01-01

BACKGROUND: Remote surgery requires automated sensors, effectors and sensor-effector communication. The NASA Smart Probe Project has focused on the sensor aspect. METHODS: The NASA Smart Probe uses neural networks and data from multiple microsensors for a unique tissue signature in real time. Animal and human trials use several probe configurations: (1) 8-microsensor probe (2.5 mm in diameter) for rodent studies (normal and subcutaneous mammary tumor tissues), and (2) 21-gauge needle probe with 3 spectroscopic fibers and an impedance microelectrode for breast cancer diagnosis in humans. Multisensor data are collected in real time (update 100 times/s) using PCs. RESULTS: Human data (collected by NASA licensee BioLuminate) from 15 women undergoing breast biopsy distinguished normal tissue from both benign tumors and breast carcinoma. Tumor margins and necrosis are rapidly detected. CONCLUSION: Real-time tissue identification is achievable. Potential applications, including probes incorporating nanoelectrode arrays, are presented. Copyright 2003 S. Karger AG, Basel.

An electrophysiological signature for proactive interference resolution in working memory.

PubMed

Du, Yingchun; Xiao, Zhuangwei; Song, Yan; Fan, Silu; Wu, Renhua; Zhang, John X

2008-08-01

We used event-related potentials (ERPs) to study the temporal dynamics of proactive interference in working memory. Participants performed a Sternberg item-recognition task to determine whether a probe was in a target memory set. Familiar negative probes were found to be more difficult to reject than less familiar ones. A fronto-central N2 component peaking around 300 ms post-probe-onset differentiated among target probes, familiar and less familiar non-target probes. The study identifies N2 as the ERP signature for proactive interference resolution. It also indicates that the resolution process occurs in the same time window as target/non-target discrimination and provides the first piece of electrophysiological evidence supporting a recent interference resolution model based on localization data [Jonides, J., Nee, D.E., 2006. Brain mechanisms of proactive interference in working memory. Neuroscience 139, 181-193].

Application of the self-generation effect to the learning of Blissymbols by persons presenting with a severe aphasia.

PubMed

Rajaram, Priya; Alant, Erna; Dada, Shakila

2012-06-01

This study investigated the application of the self-generation effect to enhance the recognition and retention of Blissymbols in persons with severe aphasia. A 2×2×3 factorial design of two treatment types (self-generation and non-generation) was used to teach two sets of Blissymbols. These were administered during 3 training days, between which were withdrawal periods of 1 day and 7 days. Recognition and retention probes were administered at intervals during the training. ANOVA analysis showed that the self-generation treatment produced no immediate recognition advantage; however, better retention of symbol recognition may have occurred over time. Hence, the potential application of the self-generation effect in enhancing the retention of Blissymbols in persons with severe aphasia may warrant further investigation.

Sprayable enzyme-activatable fluorescent probes: kinetic mapping using dynamic fluorescence imaging can help detecting tiny cancer foci (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kobayashi, Hisataka

2017-02-01

Optical fluorescence-guided imaging is increasingly used to guide surgery and endoscopic procedures. Sprayable enzyme-activatable probes are particularly useful because of high target-to-background ratios that increase sensitivity for tiny cancer foci. However, green fluorescent activatable probes suffers from interference from autofluorescence found in biological tissue. Dynamic imaging followed by the kinetic analysis could be detected local enzyme activity and used to differentiate specific fluorescence arising from an activated probe in a tumor from autofluorescence in background tissues especially when low concentrations of the dye are applied to detect tiny cancer foci. Serial fluorescence imaging was performed using various concentrations of γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) which was sprayed on the peritoneal surface with tiny implants of SHIN3-dsRed ovarian cancer tumors. Temporal differences in signal between specific green fluorescence in cancer foci and non-specific autofluorescence in background tissue was measured and processed into three kinetic maps reflecting maximum fluorescence signal (MF), wash-in rate (WIR), and area under the curve (AUC), respectively. Especially at lower concentrations, kinetic maps derived from dynamic fluorescence imaging were clearly superior to unprocessed images for detection small cancer foci.

Chemical biology-based approaches on fluorescent labeling of proteins in live cells.

PubMed

Jung, Deokho; Min, Kyoungmi; Jung, Juyeon; Jang, Wonhee; Kwon, Youngeun

2013-05-01

Recently, significant advances have been made in live cell imaging owing to the rapid development of selective labeling of proteins in vivo. Green fluorescent protein (GFP) was the first example of fluorescent reporters genetically introduced to protein of interest (POI). While GFP and various types of engineered fluorescent proteins (FPs) have been actively used for live cell imaging for many years, the size and the limited windows of fluorescent spectra of GFP and its variants set limits on possible applications. In order to complement FP-based labeling methods, alternative approaches that allow incorporation of synthetic fluorescent probes to target POIs were developed. Synthetic fluorescent probes are smaller than fluorescent proteins, often have improved photochemical properties, and offer a larger variety of colors. These synthetic probes can be introduced to POIs selectively by numerous approaches that can be largely categorized into chemical recognition-based labeling, which utilizes metal-chelating peptide tags and fluorophore-carrying metal complexes, and biological recognition-based labeling, such as (1) specific non-covalent binding between an enzyme tag and its fluorophore-carrying substrate, (2) self-modification of protein tags using substrate variants conjugated to fluorophores, (3) enzymatic reaction to generate a covalent binding between a small molecule substrate and a peptide tag, and (4) split-intein-based C-terminal labeling of target proteins. The chemical recognition-based labeling reaction often suffers from compromised selectivity of metal-ligand interaction in the cytosolic environment, consequently producing high background signals. Use of protein-substrate interactions or enzyme-mediated reactions generally shows improved specificity but each method has its limitations. Some examples are the presence of large linker protein, restriction on the choice of introducible probes due to the substrate specificity of enzymes, and competitive reaction mediated by an endogenous analogue of the introduced protein tag. These limitations have been addressed, in part, by the split-intein-based labeling approach, which introduces fluorescent probes with a minimal size (~4 amino acids) peptide tag. In this review, the advantages and the limitations of each labeling method are discussed.

Dithizone as novel and efficient chromogenic probe for cyanide detection in aqueous media through nucleophilic addition into diazenylthione moiety.

PubMed

Tavallali, Hossein; Deilamy-Rad, Gohar; Parhami, Abolfath; Kiyani, Sajede

2014-01-01

A new selective chemodosimeter probe was developed by the introduction of dithizone (DTZ) as a simple and available dye for detection of cyanide in aqueous media which enables recognition of cyanide over other competing anions such as acetate, dihydrogen phosphate, fluoride and benzoate through covalent bonding. The sensing properties of DTZ were investigated in DMSO/H2O (1:9) and have demonstrated a very high selectivity toward the cyanide anions. A reasonable recognition mechanism was suggested using UV-Vis, (1)H NMR and FTIR spectroscopy techniques. Time dependent density function theory (TDDFT) computations of UV-Vis excitation for DTZ2-CN adduct agreed well with our experimental findings. The detection limit of the new chromogenic probe was measured to be 0.48 μmol L(-1) which is much lower than most recently reported chromogenic probes for cyanide determination. The analytical utility of the method for the analysis of cyanide ions in electroplating wastewater (EPWW), human serum, tap and mineral water samples was demonstrated and the results were compared successfully with the conventional reference method. The short time response and the detection by the naked eye make the method available for the detection and quantitative determination of cyanide in a variety of real samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Precise small molecule recognition of a toxic CUG RNA repeat expansion

PubMed Central

Rzuczek, Suzanne G; Colgan, Lesley A; Nakai, Yoshio; Cameron, Michael D; Furling, Denis; Yasuda, Ryohei; Disney, Matthew D

2017-01-01

Excluding the ribosome and riboswitches, developing small molecules that selectively target RNA is a longstanding problem in chemical biology. A typical cellular RNA is difficult to target because it has little tertiary, but abundant secondary structure. We designed allele-selective compounds that target such an RNA, the toxic noncoding repeat expansion (r(CUG)exp) that causes myotonic dystrophy type 1 (DM1). We developed several strategies to generate allele-selective small molecules, including non-covalent binding, covalent binding, cleavage and on-site probe synthesis. Covalent binding and cleavage enabled target profiling in cells derived from individuals with DM1, showing precise recognition of r(CUG)exp. In the on-site probe synthesis approach, small molecules bound adjacent sites in r(CUG)exp and reacted to afford picomolar inhibitors via a proximity-based click reaction only in DM1-affected cells. We expanded this approach to image r(CUG)exp in its natural context. PMID:27941760

Precise small-molecule recognition of a toxic CUG RNA repeat expansion.

PubMed

Rzuczek, Suzanne G; Colgan, Lesley A; Nakai, Yoshio; Cameron, Michael D; Furling, Denis; Yasuda, Ryohei; Disney, Matthew D

2017-02-01

Excluding the ribosome and riboswitches, developing small molecules that selectively target RNA is a longstanding problem in chemical biology. A typical cellular RNA is difficult to target because it has little tertiary, but abundant secondary structure. We designed allele-selective compounds that target such an RNA, the toxic noncoding repeat expansion (r(CUG) exp ) that causes myotonic dystrophy type 1 (DM1). We developed several strategies to generate allele-selective small molecules, including non-covalent binding, covalent binding, cleavage and on-site probe synthesis. Covalent binding and cleavage enabled target profiling in cells derived from individuals with DM1, showing precise recognition of r(CUG) exp . In the on-site probe synthesis approach, small molecules bound adjacent sites in r(CUG) exp and reacted to afford picomolar inhibitors via a proximity-based click reaction only in DM1-affected cells. We expanded this approach to image r(CUG) exp in its natural context.

Eddy current inspection of graphite fiber components

NASA Technical Reports Server (NTRS)

Workman, G. L.; Bryson, C. C.

1990-01-01

The recognition of defects in materials properties still presents a number of problems for nondestructive testing in aerospace systems. This project attempts to utilize current capabilities in eddy current instrumentation, artificial intelligence, and robotics in order to provide insight into defining geometrical aspects of flaws in composite materials which are capable of being evaluated using eddy current inspection techniques. The unique capabilities of E-probes and horseshoe probes for inspecting probes for inspecting graphite fiber materials were evaluated and appear to hold great promise once the technology development matures. The initial results are described of modeling eddy current interactions with certain flaws in graphite fiber samples.

Theoretical Design of a Two-Photon Fluorescent Probe for Nitric Oxide with Enhanced Emission Induced by Photoninduced Electron Transfer.

PubMed

Zhang, Yujin; Leng, Jiancai; Hu, Wei

2018-04-25

In the present work, we systematically investigate the sensing abilities of two recently literature-reported two-photon fluorescent NO probes, i.e., the o-phenylenediamine derivative of Nile Red and the p-phenylenediamine derivative of coumarin. The recognition mechanisms of these probes are studied by using the molecular orbital classifying method, which demonstrates the photoinduced electron transfer process. In addition, we have designed two new probes by swapping receptor units present on fluorophores, i.e., the p-phenylenediamine derivative of Nile Red and the o-phenylenediamine derivative of coumarin. However, it illustrates that only the latter has ability to function as off-on typed fluorescent probe for NO. More importantly, calculations on the two-photon absorption properties of the probes demonstrate that both receptor derivatives of coumarin possess larger TPA cross-sections than Nile Red derivatives, which makes a better two photon fluorescent probe. Our theoretical investigations reveal that the underlying mechanism satisfactorily explain the experimental results, providing a theoretical basis on the structure-property relationships which is beneficial to developing new two-photon fluorescent probes for NO.

Incorporation of extra amino acids in peptide recognition probe to improve specificity and selectivity of an electrochemical peptide-based sensor.

PubMed

Zaitouna, Anita J; Maben, Alex J; Lai, Rebecca Y

2015-07-30

We investigated the effect of incorporating extra amino acids (AA) at the n-terminus of the thiolated and methylene blue-modified peptide probe on both specificity and selectivity of an electrochemical peptide-based (E-PB) HIV sensor. The addition of a flexible (SG)3 hexapeptide is, in particular, useful in improving sensor selectivity, whereas the addition of a highly hydrophilic (EK)3 hexapeptide has shown to be effective in enhancing sensor specificity. Overall, both E-PB sensors fabricated using peptide probes with the added AA (SG-EAA and EK-EAA) showed better specificity and selectivity, especially when compared to the sensor fabricated using a peptide probe without the extra AA (EAA). For example, the selectivity factor recorded in the 50% saliva was ∼2.5 for the EAA sensor, whereas the selectivity factor was 7.8 for both the SG-EAA and EK-EAA sensors. Other sensor properties such as the limit of detection and dynamic range were minimally affected by the addition of the six AA sequence. The limit of detection was 0.5 nM for the EAA sensor and 1 nM for both SG-EAA and EK-EAA sensors. The saturation target concentration was ∼200 nM for all three sensors. Unlike previously reported E-PB HIV sensors, the peptide probe functions as both the recognition element and antifouling passivating agent; this modification eliminates the need to include an additional antifouling diluent, which simplifies the sensor design and fabrication protocol. Copyright © 2015 Elsevier B.V. All rights reserved.

GMR-based eddy current probe for weld seam inspection and its non-scanning detection study

NASA Astrophysics Data System (ADS)

Gao, Peng; Wang, Chao; Li, Yang; Wang, Libin; Cong, Zheng; Zhi, Ya

2017-04-01

Eddy current testing is one of the most important non-destructive testing methods for welding defects detection. This paper presents the use of a probe consisting of 4 giant magneto-resistive (GMR) sensors to detect weld defects. Information from four measuring points above and on both sides of the weld seam is collected at the same time. By setting the GMR sensors' sensing axes perpendicular to the direction of the excitation magnetic field, the information collected mainly reflects the change in the eddy current which is caused by defects. Digital demodulation technology is applied to extract the real part and imaginary part of the GMR sensors' output signals. The variables containing directional information of the magnetic field are introduced. Based on the data from the four GMR (4-GMR) sensors' output signals, four values, Ran, Mean, Var and k are selected as the feature quantities for defect recognition. Experiments are carried out on weld seams with and without defects, and the detection outputs are given in this paper. The 4-GMR probe is also employed to investigate non-scanning weld defect detection and the four feature quantities (Ran, Mean, Var and k) are studied to evaluate weld quality. The non-scanning weld defect detection is presented. A support vector machine is used to classify and discriminate welds with and without defects. Experiments carried out show that through the method in this paper, the recognition rate is 92% for welds without defects and 90% for welds with defects, with an overall recognition rate of 90.9%, indicating that this method could effectively detect weld defects.

Biometric recognition using 3D ear shape.

PubMed

Yan, Ping; Bowyer, Kevin W

2007-08-01

Previous works have shown that the ear is a promising candidate for biometric identification. However, in prior work, the preprocessing of ear images has had manual steps and algorithms have not necessarily handled problems caused by hair and earrings. We present a complete system for ear biometrics, including automated segmentation of the ear in a profile view image and 3D shape matching for recognition. We evaluated this system with the largest experimental study to date in ear biometrics, achieving a rank-one recognition rate of 97.8 percent for an identification scenario and an equal error rate of 1.2 percent for a verification scenario on a database of 415 subjects and 1,386 total probes.

Cavitand-grafted silicon microcantilevers as a universal probe for illicit and designer drugs in water.

PubMed

Biavardi, Elisa; Federici, Stefania; Tudisco, Cristina; Menozzi, Daniela; Massera, Chiara; Sottini, Andrea; Condorelli, Guglielmo G; Bergese, Paolo; Dalcanale, Enrico

2014-08-25

The direct, clean, and unbiased transduction of molecular recognition into a readable and reproducible response is the biggest challenge associated to the use of synthetic receptors in sensing. All possible solutions demand the mastering of molecular recognition at the solid-liquid interface as prerequisite. The socially relevant issue of screening amine-based illicit and designer drugs is addressed by nanomechanical recognition at the silicon-water interface. The methylamino moieties of different drugs are all first recognized by a single cavitand receptor through a synergistic set of weak interactions. The peculiar recognition ability of the cavitand is then transferred with high fidelity and robustness on silicon microcantilevers and harnessed to realize a nanomechanical device for label-free detection of these drugs in water. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A new pyrene based highly sensitive fluorescence probe for copper(II) and fluoride with living cell application.

PubMed

Goswami, Shyamaprosad; Chakraborty, Shampa; Paul, Sima; Halder, Sandipan; Panja, Sukanya; Mukhopadhyay, Subhra Kanti

2014-05-21

A new pyrene based fluorescence probe has been synthesized for fluorogenic detection of Cu(2+) in acetonitrile-aqueous media (7 : 3 CH3CN-HEPES buffer, v/v, at pH 7.5) with bioimaging in both prokaryotic (Candida albicans cells) and eukaryotic (Tecoma stans pollen cells) living cells. The anion recognition properties of the sensor have also been studied in acetonitrile by fluorescence methods which show remarkable sensitivity toward fluoride over other anions examined.

All-optical gain-clamped wideband serial EDFA with ring-shaped laser

NASA Astrophysics Data System (ADS)

Lu, Yung-Hsin; Chi, Sien

2004-01-01

We experimentally investigate the static and dynamic properties of all-optical gain-clamped wideband (1530-1600 nm) serial erbium-doped fiber amplifier with a single ring-shaped laser, which consists of a circulator and a fiber Bragg grating at the output end. The lasing light passing through the second stage is intentionally blocked at the output end by a C/L-band wavelength division multiplexer owning the huge insertion loss, and thus, the copropagating ring-laser light is formed by the first stage. This design can simultaneously clamp the gains of 1547 and 1584 nm probes near 14 dB and shows the same dynamic range of input power up to -4 dBm for conventional band and long-wavelength band. Furthermore, the transient responses of 1551 and 1596 nm surviving channels exhibit small power excursions (<0.54 dB) as the total saturating tone with -2 dBm is modulated on and off at 270 Hz.

A relay identification fluorescence probe for Fe3 + and phosphate anion and its applications

NASA Astrophysics Data System (ADS)

Tang, Xu; Wang, Yun; Han, Juan; Ni, Liang; Wang, Lei; Li, Longhua; Zhang, Huiqin; Li, Cheng; Li, Jing; Li, Haoran

2018-02-01

A simple relay identification fluorescence probe for Fe3 + and phosphate anion with ;on-off-on; switching was designed and synthesized based on the phenylthiazole and biphenylcarbonitrile. Probe 1 displayed highly selective and sensitive recognition to Fe3 + in HEPES aqueous buffer (EtOH/H2O = 2:8, v/v, pH = 7.4) solutions. The optimized structures and HOMO and LUMO of probe 1 and [1-Fe3 +] complex were obtained by the density functional theory (DFT) calculations with B3LYP as the exchange and correlation functional using a suite of Gaussian 09 programs. The [1-Fe3 +] complex solution also showed a high selectivity toward PO43 -. The lower limits of detection of probe 1 to Fe3 + and [1-Fe3 +] complex to PO43 - were estimated to 1.09 × 10- 7 M and 1.86 × 10- 7 M. Besides, the probe 1 also was used to detected the target ions in real water sample and living cells successfully.

Dual representation of item positions in verbal short-term memory: Evidence for two access modes.

PubMed

Lange, Elke B; Verhaeghen, Paul; Cerella, John

Memory sets of N = 1~5 digits were exposed sequentially from left-to-right across the screen, followed by N recognition probes. Probes had to be compared to memory list items on identity only (Sternberg task) or conditional on list position. Positions were probed randomly or in left-to-right order. Search functions related probe response times to set size. Random probing led to ramped, "Sternbergian" functions whose intercepts were elevated by the location requirement. Sequential probing led to flat search functions-fast responses unaffected by set size. These results suggested that items in STM could be accessed either by a slow search-on-identity followed by recovery of an associated location tag, or in a single step by following item-to-item links in study order. It is argued that this dual coding of location information occurs spontaneously at study, and that either code can be utilised at retrieval depending on test demands.

Selective and “turn-off” fluorimetric detection of mercury(II) based on coumarinyldithiolane and coumarinyldithiane in aqueous solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Yuan, E-mail: guoyuan@nwu.edu.cn; Institut de Chimie Organique et Analytique, Université d’Orléans, 45067 Orléans Cedex 2; An, Jing

2015-03-15

Graphical abstract: Visual fluorescence emission of probe 3a. - Highlights: • Five novel coumarin-based fluorescent probes were developed. • A reasonable reaction mechanism was proposed and verified. • All the probes showed excellent optical properties. - Abstract: In this work, five novel coumarin-based fluorescent probes for mercury ions were developed. The recognition of mercury ions was performed via the mercury(II)-promoted desulfurization of the probes and a reasonable reaction mechanism was proposed and verified by thin layer chromatography (TLC), {sup 1}H nuclear magnetic resonance ({sup 1}H NMR) and fluorescence intensity measurements. All the probes showed excellent optical properties and exclusively distinguishmore » mercury ions from various metal ions in aqueous solutions at pH 7.4. The linear response of the fluorescence emission intensity for all the probes to the concentration of mercury ions was obtained over a wide range of 0.06–1.5 μM (0.06–0.9 μM for probe 3e). In addition, the biological toxicity and the confocal fluorescence images of probe 3a were also tested on MCF-7 cells.« less

Boosting Long-Term Memory via Wakeful Rest: Intentional Rehearsal Is Not Necessary, Consolidation Is Sufficient

PubMed Central

Dewar, Michaela; Alber, Jessica; Cowan, Nelson; Della Sala, Sergio

2014-01-01

People perform better on tests of delayed free recall if learning is followed immediately by a short wakeful rest than by a short period of sensory stimulation. Animal and human work suggests that wakeful resting provides optimal conditions for the consolidation of recently acquired memories. However, an alternative account cannot be ruled out, namely that wakeful resting provides optimal conditions for intentional rehearsal of recently acquired memories, thus driving superior memory. Here we utilised non-recallable words to examine whether wakeful rest boosts long-term memory, even when new memories could not be rehearsed intentionally during the wakeful rest delay. The probing of non-recallable words requires a recognition paradigm. Therefore, we first established, via Experiment 1, that the rest-induced boost in memory observed via free recall can be replicated in a recognition paradigm, using concrete nouns. In Experiment 2, participants heard 30 non-recallable non-words, presented as ‘foreign names in a bridge club abroad’ and then either rested wakefully or played a visual spot-the-difference game for 10 minutes. Retention was probed via recognition at two time points, 15 minutes and 7 days after presentation. As in Experiment 1, wakeful rest boosted recognition significantly, and this boost was maintained for at least 7 days. Our results indicate that the enhancement of memory via wakeful rest is not dependent upon intentional rehearsal of learned material during the rest period. We thus conclude that consolidation is sufficient for this rest-induced memory boost to emerge. We propose that wakeful resting allows for superior memory consolidation, resulting in stronger and/or more veridical representations of experienced events which can be detected via tests of free recall and recognition. PMID:25333957

Interdependence of Inhibitor Recognition in HIV-1 Protease

PubMed Central

2017-01-01

Molecular recognition is a highly interdependent process. Subsite couplings within the active site of proteases are most often revealed through conditional amino acid preferences in substrate recognition. However, the potential effect of these couplings on inhibition and thus inhibitor design is largely unexplored. The present study examines the interdependency of subsites in HIV-1 protease using a focused library of protease inhibitors, to aid in future inhibitor design. Previously a series of darunavir (DRV) analogs was designed to systematically probe the S1′ and S2′ subsites. Co-crystal structures of these analogs with HIV-1 protease provide the ideal opportunity to probe subsite interdependency. All-atom molecular dynamics simulations starting from these structures were performed and systematically analyzed in terms of atomic fluctuations, intermolecular interactions, and water structure. These analyses reveal that the S1′ subsite highly influences other subsites: the extension of the hydrophobic P1′ moiety results in 1) reduced van der Waals contacts in the P2′ subsite, 2) more variability in the hydrogen bond frequencies with catalytic residues and the flap water, and 3) changes in the occupancy of conserved water sites both proximal and distal to the active site. In addition, one of the monomers in this homodimeric enzyme has atomic fluctuations more highly correlated with DRV than the other monomer. These relationships intricately link the HIV-1 protease subsites and are critical to understanding molecular recognition and inhibitor binding. More broadly, the interdependency of subsite recognition within an active site requires consideration in the selection of chemical moieties in drug design; this strategy is in contrast to what is traditionally done with independent optimization of chemical moieties of an inhibitor. PMID:28358514

Interdependence of Inhibitor Recognition in HIV-1 Protease.

PubMed

Paulsen, Janet L; Leidner, Florian; Ragland, Debra A; Kurt Yilmaz, Nese; Schiffer, Celia A

2017-05-09

Molecular recognition is a highly interdependent process. Subsite couplings within the active site of proteases are most often revealed through conditional amino acid preferences in substrate recognition. However, the potential effect of these couplings on inhibition and thus inhibitor design is largely unexplored. The present study examines the interdependency of subsites in HIV-1 protease using a focused library of protease inhibitors, to aid in future inhibitor design. Previously a series of darunavir (DRV) analogs was designed to systematically probe the S1' and S2' subsites. Co-crystal structures of these analogs with HIV-1 protease provide the ideal opportunity to probe subsite interdependency. All-atom molecular dynamics simulations starting from these structures were performed and systematically analyzed in terms of atomic fluctuations, intermolecular interactions, and water structure. These analyses reveal that the S1' subsite highly influences other subsites: the extension of the hydrophobic P1' moiety results in 1) reduced van der Waals contacts in the P2' subsite, 2) more variability in the hydrogen bond frequencies with catalytic residues and the flap water, and 3) changes in the occupancy of conserved water sites both proximal and distal to the active site. In addition, one of the monomers in this homodimeric enzyme has atomic fluctuations more highly correlated with DRV than the other monomer. These relationships intricately link the HIV-1 protease subsites and are critical to understanding molecular recognition and inhibitor binding. More broadly, the interdependency of subsite recognition within an active site requires consideration in the selection of chemical moieties in drug design; this strategy is in contrast to what is traditionally done with independent optimization of chemical moieties of an inhibitor.

Boosting long-term memory via wakeful rest: intentional rehearsal is not necessary, consolidation is sufficient.

PubMed

Dewar, Michaela; Alber, Jessica; Cowan, Nelson; Della Sala, Sergio

2014-01-01

People perform better on tests of delayed free recall if learning is followed immediately by a short wakeful rest than by a short period of sensory stimulation. Animal and human work suggests that wakeful resting provides optimal conditions for the consolidation of recently acquired memories. However, an alternative account cannot be ruled out, namely that wakeful resting provides optimal conditions for intentional rehearsal of recently acquired memories, thus driving superior memory. Here we utilised non-recallable words to examine whether wakeful rest boosts long-term memory, even when new memories could not be rehearsed intentionally during the wakeful rest delay. The probing of non-recallable words requires a recognition paradigm. Therefore, we first established, via Experiment 1, that the rest-induced boost in memory observed via free recall can be replicated in a recognition paradigm, using concrete nouns. In Experiment 2, participants heard 30 non-recallable non-words, presented as 'foreign names in a bridge club abroad' and then either rested wakefully or played a visual spot-the-difference game for 10 minutes. Retention was probed via recognition at two time points, 15 minutes and 7 days after presentation. As in Experiment 1, wakeful rest boosted recognition significantly, and this boost was maintained for at least 7 days. Our results indicate that the enhancement of memory via wakeful rest is not dependent upon intentional rehearsal of learned material during the rest period. We thus conclude that consolidation is sufficient for this rest-induced memory boost to emerge. We propose that wakeful resting allows for superior memory consolidation, resulting in stronger and/or more veridical representations of experienced events which can be detected via tests of free recall and recognition.

A split-beam probe-pump-probe scheme for femtosecond time resolved protein X-ray crystallography

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Thor, Jasper J.; Madsen, Anders

In order to exploit the femtosecond pulse duration of X-ray Free-Electron Lasers (XFEL) operating in the hard X-ray regime for ultrafast time-resolved protein crystallography experiments, critical parameters that determine the crystallographic signal-to-noise (I/σI) must be addressed. For single-crystal studies under low absorbed dose conditions, it has been shown that the intrinsic pulse intensity stability as well as mode structure and jitter of this structure, significantly affect the crystallographic signal-to-noise. Here, geometrical parameters are theoretically explored for a three-beam scheme: X-ray probe, optical pump, X-ray probe (or “probe-pump-probe”) which will allow experimental determination of the photo-induced structure factor amplitude differences, ΔF,more » in a ratiometric manner, thereby internally referencing the intensity noise of the XFEL source. In addition to a non-collinear split-beam geometry which separates un-pumped and pumped diffraction patterns on an area detector, applying an additional convergence angle to both beams by focusing leads to integration over mosaic blocks in the case of well-ordered stationary protein crystals. Ray-tracing X-ray diffraction simulations are performed for an example using photoactive yellow protein crystals in order to explore the geometrical design parameters which would be needed. The specifications for an X-ray split and delay instrument that implements both an offset angle and focused beams are discussed, for implementation of a probe-pump-probe scheme at the European XFEL. We discuss possible extension of single crystal studies to serial femtosecond crystallography, particularly in view of the expected X-ray damage and ablation due to the first probe pulse.« less

A split-beam probe-pump-probe scheme for femtosecond time resolved protein X-ray crystallography

DOE PAGES

van Thor, Jasper J.; Madsen, Anders

2015-01-01

In order to exploit the femtosecond pulse duration of X-ray Free-Electron Lasers (XFEL) operating in the hard X-ray regime for ultrafast time-resolved protein crystallography experiments, critical parameters that determine the crystallographic signal-to-noise (I/σI) must be addressed. For single-crystal studies under low absorbed dose conditions, it has been shown that the intrinsic pulse intensity stability as well as mode structure and jitter of this structure, significantly affect the crystallographic signal-to-noise. Here, geometrical parameters are theoretically explored for a three-beam scheme: X-ray probe, optical pump, X-ray probe (or “probe-pump-probe”) which will allow experimental determination of the photo-induced structure factor amplitude differences, ΔF,more » in a ratiometric manner, thereby internally referencing the intensity noise of the XFEL source. In addition to a non-collinear split-beam geometry which separates un-pumped and pumped diffraction patterns on an area detector, applying an additional convergence angle to both beams by focusing leads to integration over mosaic blocks in the case of well-ordered stationary protein crystals. Ray-tracing X-ray diffraction simulations are performed for an example using photoactive yellow protein crystals in order to explore the geometrical design parameters which would be needed. The specifications for an X-ray split and delay instrument that implements both an offset angle and focused beams are discussed, for implementation of a probe-pump-probe scheme at the European XFEL. We discuss possible extension of single crystal studies to serial femtosecond crystallography, particularly in view of the expected X-ray damage and ablation due to the first probe pulse.« less

A split-beam probe-pump-probe scheme for femtosecond time resolved protein X-ray crystallography

PubMed Central

van Thor, Jasper J.; Madsen, Anders

2015-01-01

In order to exploit the femtosecond pulse duration of X-ray Free-Electron Lasers (XFEL) operating in the hard X-ray regime for ultrafast time-resolved protein crystallography experiments, critical parameters that determine the crystallographic signal-to-noise (I/σI) must be addressed. For single-crystal studies under low absorbed dose conditions, it has been shown that the intrinsic pulse intensity stability as well as mode structure and jitter of this structure, significantly affect the crystallographic signal-to-noise. Here, geometrical parameters are theoretically explored for a three-beam scheme: X-ray probe, optical pump, X-ray probe (or “probe-pump-probe”) which will allow experimental determination of the photo-induced structure factor amplitude differences, ΔF, in a ratiometric manner, thereby internally referencing the intensity noise of the XFEL source. In addition to a non-collinear split-beam geometry which separates un-pumped and pumped diffraction patterns on an area detector, applying an additional convergence angle to both beams by focusing leads to integration over mosaic blocks in the case of well-ordered stationary protein crystals. Ray-tracing X-ray diffraction simulations are performed for an example using photoactive yellow protein crystals in order to explore the geometrical design parameters which would be needed. The specifications for an X-ray split and delay instrument that implements both an offset angle and focused beams are discussed, for implementation of a probe-pump-probe scheme at the European XFEL. We discuss possible extension of single crystal studies to serial femtosecond crystallography, particularly in view of the expected X-ray damage and ablation due to the first probe pulse. PMID:26798786

The cognitive neuroscience of person identification.

PubMed

Biederman, Irving; Shilowich, Bryan E; Herald, Sarah B; Margalit, Eshed; Maarek, Rafael; Meschke, Emily X; Hacker, Catrina M

2018-02-14

We compare and contrast five differences between person identification by voice and face. 1. There is little or no cost when a familiar face is to be recognized from an unrestricted set of possible faces, even at Rapid Serial Visual Presentation (RSVP) rates, but the accuracy of familiar voice recognition declines precipitously when the set of possible speakers is increased from one to a mere handful. 2. Whereas deficits in face recognition are typically perceptual in origin, those with normal perception of voices can manifest severe deficits in their identification. 3. Congenital prosopagnosics (CPros) and congenital phonagnosics (CPhon) are generally unable to imagine familiar faces and voices, respectively. Only in CPros, however, is this deficit a manifestation of a general inability to form visual images of any kind. CPhons report no deficit in imaging non-voice sounds. 4. The prevalence of CPhons of 3.2% is somewhat higher than the reported prevalence of approximately 2.0% for CPros in the population. There is evidence that CPhon represents a distinct condition statistically and not just normal variation. 5. Face and voice recognition proficiency are uncorrelated rather than reflecting limitations of a general capacity for person individuation. Copyright © 2018 Elsevier Ltd. All rights reserved.

A general strategy for developing cell-permeable photo-modulatable organic fluorescent probes for live-cell super-resolution imaging.

PubMed

Pan, Deng; Hu, Zhe; Qiu, Fengwu; Huang, Zhen-Li; Ma, Yilong; Wang, Yina; Qin, Lingsong; Zhang, Zhihong; Zeng, Shaoqun; Zhang, Yu-Hui

2014-11-20

Single-molecule localization microscopy (SMLM) achieves super-resolution imaging beyond the diffraction limit but critically relies on the use of photo-modulatable fluorescent probes. Here we report a general strategy for constructing cell-permeable photo-modulatable organic fluorescent probes for live-cell SMLM by exploiting the remarkable cytosolic delivery ability of a cell-penetrating peptide (rR)3R2. We develop photo-modulatable organic fluorescent probes consisting of a (rR)3R2 peptide coupled to a cell-impermeable organic fluorophore and a recognition unit. Our results indicate that these organic probes are not only cell permeable but can also specifically and directly label endogenous targeted proteins. Using the probes, we obtain super-resolution images of lysosomes and endogenous F-actin under physiological conditions. We resolve the dynamics of F-actin with 10 s temporal resolution in live cells and discern fine F-actin structures with diameters of ~80 nm. These results open up new avenues in the design of fluorescent probes for live-cell super-resolution imaging.

Fluorescence self-quenching assay for the detection of target collagen sequences using a short probe peptide.

PubMed

Nian, Linge; Hu, Yue; Fu, Caihong; Song, Chen; Wang, Jie; Xiao, Jianxi

2018-01-01

The development of novel assays to detect collagen fragments is of utmost importance for diagnostic, prognostic and therapeutic decisions in various collagen-related diseases, and one essential question is to discover probe peptides that can specifically recognize target collagen sequences. Herein we have developed the fluorescence self-quenching assay as a convenient tool to screen the capability of a series of fluorescent probe peptides of variable lengths to bind with target collagen peptides. We have revealed that the targeting ability of probe peptides is length-dependent, and have discovered a relatively short probe peptide FAM-G(POG) 8 capable to identify the target peptide. We have further demonstrated that fluorescence self-quenching assay together with this short probe peptide can be applied to specifically detect the desired collagen fragment in complex biological media. Fluorescence self-quenching assay provides a powerful new tool to discover effective peptides for the recognition of collagen biomarkers, and it may have great potential to identify probe peptides for various protein biomarkers involved in pathological conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Large volume serial section tomography by Xe Plasma FIB dual beam microscopy.

PubMed

Burnett, T L; Kelley, R; Winiarski, B; Contreras, L; Daly, M; Gholinia, A; Burke, M G; Withers, P J

2016-02-01

Ga(+) Focused Ion Beam-Scanning Electron Microscopes (FIB-SEM) have revolutionised the level of microstructural information that can be recovered in 3D by block face serial section tomography (SST), as well as enabling the site-specific removal of smaller regions for subsequent transmission electron microscope (TEM) examination. However, Ga(+) FIB material removal rates limit the volumes and depths that can be probed to dimensions in the tens of microns range. Emerging Xe(+) Plasma Focused Ion Beam-Scanning Electron Microscope (PFIB-SEM) systems promise faster removal rates. Here we examine the potential of the method for large volume serial section tomography as applied to bainitic steel and WC-Co hard metals. Our studies demonstrate that with careful control of milling parameters precise automated serial sectioning can be achieved with low levels of milling artefacts at removal rates some 60× faster. Volumes that are hundreds of microns in dimension have been collected using fully automated SST routines in feasible timescales (<24h) showing good grain orientation contrast and capturing microstructural features at the tens of nanometres to the tens of microns scale. Accompanying electron back scattered diffraction (EBSD) maps show high indexing rates suggesting low levels of surface damage. Further, under high current Ga(+) FIB milling WC-Co is prone to amorphisation of WC surface layers and phase transformation of the Co phase, neither of which have been observed at PFIB currents as high as 60nA at 30kV. Xe(+) PFIB dual beam microscopes promise to radically extend our capability for 3D tomography, 3D EDX, 3D EBSD as well as correlative tomography. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Cd(II)-terpyridine-based complex as a ratiometric fluorescent probe for pyrophosphate detection in solution and as an imaging agent in living cells.

PubMed

Jiao, Shu-Yan; Li, Kun; Zhang, Wei; Liu, Yan-Hong; Huang, Zeng; Yu, Xiao-Qi

2015-01-21

The terpyridine anthracene ligand was synthesized and characterized. is a ratiometric fluorescent probe for Cd(2+) with a recognition mechanism based on intramolecular charge transfer (ICT). An complex was isolated, and its structure was established using single-crystal XRD. The complex was able to serve as a novel reversible chemosensing ensemble to allow ratiometric response to pyrophosphate (PPi) in aqueous media. Moreover, the fluorescence imaging in living cells from these two emission channels suggested that was a ratiometric probe for Cd(2+), and the in situ generated complex was also a ratiometric ensemble for PPi detection in living cells.

YADCLAN: yet another digitally-controlled linear artificial neuron.

PubMed

Frenger, Paul

2003-01-01

This paper updates the author's 1999 RMBS presentation on digitally controlled linear artificial neuron design. Each neuron is based on a standard operational amplifier having excitatory and inhibitory inputs, variable gain, an amplified linear analog output and an adjustable threshold comparator for digital output. This design employs a 1-wire serial network of digitally controlled potentiometers and resistors whose resistance values are set and read back under microprocessor supervision. This system embodies several unique and useful features, including: enhanced neuronal stability, dynamic reconfigurability and network extensibility. This artificial neuronal is being employed for feature extraction and pattern recognition in an advanced robotic application.

Global similarity predicts dissociation of classification and recognition: evidence questioning the implicit-explicit learning distinction in amnesia.

PubMed

Jamieson, Randall K; Holmes, Signy; Mewhort, D J K

2010-11-01

Dissociation of classification and recognition in amnesia is widely taken to imply 2 functional systems: an implicit procedural-learning system that is spared in amnesia and an explicit episodic-learning system that is compromised. We argue that both tasks reflect the global similarity of probes to memory. In classification, subjects sort unstudied grammatical exemplars from lures, whereas in recognition, they sort studied grammatical exemplars from lures. Hence, global similarity is necessarily greater in recognition than in classification. Moreover, a grammatical exemplar's similarity to studied exemplars is a nonlinear function of the integrity of the data in memory. Assuming that data integrity is better for control subjects than for subjects with amnesia, the nonlinear relation combined with the advantage for recognition over classification predicts the dissociation of recognition and classification. To illustrate the dissociation of recognition and classification in healthy undergraduates, we manipulated study time to vary the integrity of the data in memory and brought the dissociation under experimental control. We argue that the dissociation reflects a general cost in memory rather than a selective impairment of separate procedural and episodic systems. (c) 2010 APA, all rights reserved

Low- Z polymer sample supports for fixed-target serial femtosecond X-ray crystallography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feld, Geoffrey K.; Heymann, Michael; Benner, W. Henry

X-ray free-electron lasers (XFELs) offer a new avenue to the structural probing of complex materials, including biomolecules. Delivery of precious sample to the XFEL beam is a key consideration, as the sample of interest must be serially replaced after each destructive pulse. The fixed-target approach to sample delivery involves depositing samples on a thin-film support and subsequent serial introduction via a translating stage. Some classes of biological materials, including two-dimensional protein crystals, must be introduced on fixed-target supports, as they require a flat surface to prevent sample wrinkling. A series of wafer and transmission electron microscopy (TEM)-style grid supports constructedmore » of low- Z plastic have been custom-designed and produced. Aluminium TEM grid holders were engineered, capable of delivering up to 20 different conventional or plastic TEM grids using fixed-target stages available at the Linac Coherent Light Source (LCLS). As proof-of-principle, X-ray diffraction has been demonstrated from two-dimensional crystals of bacteriorhodopsin and three-dimensional crystals of anthrax toxin protective antigen mounted on these supports at the LCLS. In conclusion, the benefits and limitations of these low- Z fixed-target supports are discussed; it is the authors' belief that they represent a viable and efficient alternative to previously reported fixed-target supports for conducting diffraction studies with XFELs.« less

Clinical tests of an ultrasonic periodontal probe

NASA Astrophysics Data System (ADS)

Hinders, Mark K.; Lynch, John E.; McCombs, Gayle B.

2002-05-01

A new ultrasonic periodontal probe has been developed that offers the potential for earlier detection of periodontal disease activity, non-invasive diagnosis, and greater reliability of measurement. A comparison study of the ultrasonic probe to both a manual probe, and a controlled-force probe was conducted to evaluate its clinical effectiveness. Twelve patients enrolled into this study. Two half-month examinations were conducted on each patient, scheduled one hour apart. A one-way analysis of variance was performed to compare the results for the three sets of probing depth measurements, followed by a repeated measures analysis to assess the reproducibility of the different probing techniques. These preliminary findings indicate that manual and ultrasonic probing measure different features of the pocket. Therefore, it is not obvious how the two depth measurements correspond to each other. However, both methods exhibited a similar tendency toward increasing pocket depths as Gingival Index scores increased. Based on the small sample size, further studies need to be conducted using a larger population of patients exhibiting a wider range of disease activity. In addition, studies that allow histological examination of the pocket after probing will help further evaluate the clinical effectiveness the ultrasonic probe. Future studies will also aid in the development of more effective automated feature recognition algorithms that convert the ultrasonic echoes into pocket depth readings.

Large capacity temporary visual memory.

PubMed

Endress, Ansgar D; Potter, Mary C

2014-04-01

Visual working memory (WM) capacity is thought to be limited to 3 or 4 items. However, many cognitive activities seem to require larger temporary memory stores. Here, we provide evidence for a temporary memory store with much larger capacity than past WM capacity estimates. Further, based on previous WM research, we show that a single factor--proactive interference--is sufficient to bring capacity estimates down to the range of previous WM capacity estimates. Participants saw a rapid serial visual presentation of 5-21 pictures of familiar objects or words presented at rates of 4/s or 8/s, respectively, and thus too fast for strategies such as rehearsal. Recognition memory was tested with a single probe item. When new items were used on all trials, no fixed memory capacities were observed, with estimates of up to 9.1 retained pictures for 21-item lists, and up to 30.0 retained pictures for 100-item lists, and no clear upper bound to how many items could be retained. Further, memory items were not stored in a temporally stable form of memory but decayed almost completely after a few minutes. In contrast, when, as in most WM experiments, a small set of items was reused across all trials, thus creating proactive interference among items, capacity remained in the range reported in previous WM experiments. These results show that humans have a large-capacity temporary memory store in the absence of proactive interference, and raise the question of whether temporary memory in everyday cognitive processing is severely limited, as in WM experiments, or has the much larger capacity found in the present experiments.

MassImager: A software for interactive and in-depth analysis of mass spectrometry imaging data.

PubMed

He, Jiuming; Huang, Luojiao; Tian, Runtao; Li, Tiegang; Sun, Chenglong; Song, Xiaowei; Lv, Yiwei; Luo, Zhigang; Li, Xin; Abliz, Zeper

2018-07-26

Mass spectrometry imaging (MSI) has become a powerful tool to probe molecule events in biological tissue. However, it is a widely held viewpoint that one of the biggest challenges is an easy-to-use data processing software for discovering the underlying biological information from complicated and huge MSI dataset. Here, a user-friendly and full-featured MSI software including three subsystems, Solution, Visualization and Intelligence, named MassImager, is developed focusing on interactive visualization, in-situ biomarker discovery and artificial intelligent pathological diagnosis. Simplified data preprocessing and high-throughput MSI data exchange, serialization jointly guarantee the quick reconstruction of ion image and rapid analysis of dozens of gigabytes datasets. It also offers diverse self-defined operations for visual processing, including multiple ion visualization, multiple channel superposition, image normalization, visual resolution enhancement and image filter. Regions-of-interest analysis can be performed precisely through the interactive visualization between the ion images and mass spectra, also the overlaid optical image guide, to directly find out the region-specific biomarkers. Moreover, automatic pattern recognition can be achieved immediately upon the supervised or unsupervised multivariate statistical modeling. Clear discrimination between cancer tissue and adjacent tissue within a MSI dataset can be seen in the generated pattern image, which shows great potential in visually in-situ biomarker discovery and artificial intelligent pathological diagnosis of cancer. All the features are integrated together in MassImager to provide a deep MSI processing solution at the in-situ metabolomics level for biomarker discovery and future clinical pathological diagnosis. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Ligation-rolling circle amplification combined with γ-cyclodextrin mediated stemless molecular beacon for sensitive and specific genotyping of single-nucleotide polymorphism.

PubMed

Zou, Zhen; Qing, Zhihe; He, Xiaoxiao; Wang, Kemin; He, Dinggeng; Shi, Hui; Yang, Xue; Qing, Taiping; Yang, Xiaoxiao

2014-07-01

A novel approach for highly sensitive and selective genotyping of single-nucleotide polymorphism (SNP) has been developed based on ligation-rolling circle amplification (L-RCA) and stemless molecular beacon. In this approach, two tailored DNA probes were involved. The stemless molecular beacon, formed through the inclusion interactions of γ-cyclodextrin (γ-CD) and bis-pyrene labeled DNA fragment, was served as signal probe. In the absence of mutant target, the two pyrene molecules were bound in the γ-CD cavity to form an excimer and showed a strong fluorescence at 475 nm. It was here named γ-CD-P-MB. The padlock DNA probe was designed as recognition probe. Upon the recognition of a point mutation DNA targets, the padlock probe was ligated to generate a circular template. An RCA amplification was then initiated using the circular template in the presence of Phi29 polymerase and dNTPs. The L-RCA products, containing repetitive sequence units, subsequently hybridized with the γ-CD-P-MB. This made pyrene molecules away from γ-CD cavity and caused a decrease of excimer fluorescence. As a proof-of-concept, SNP typing of β-thalassemia gene at position -28 was investigated using this approach. The detection limit of mutated target was determined to be 40 fM. In addition, DNA ligase offered high fidelity in distinguishing the mismatched bases at the ligation site, resulting in positive detection of mutant target even when the ratio of the wildtype to the mutant is 999:1. Given these attractive characteristics, the developed approach might provide a great genotyping platform for pathogenic diagnosis and genetic analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

Probing the inner space of salt-bridged calix[5]arene capsules.

PubMed

Brancatelli, Giovanna; Gattuso, Giuseppe; Geremia, Silvano; Notti, Anna; Pappalardo, Sebastiano; Parisi, Melchiorre F; Pisagatti, Ilenia

2014-05-02

A combined DOSY and XRD study indicates that a carboxylcalix[5]arene receptor is able to encapsulate α,ω-diamines of appropriate length by means of a proton-transfer-mediated recognition process followed by salt-bridge-assisted bis-endo-complexation.

An azodye-rhodamine-based fluorescent and colorimetric probe specific for the detection of Pd(2+) in aqueous ethanolic solution: synthesis, XRD characterization, computational studies and imaging in live cells.

PubMed

Mahapatra, Ajit Kumar; Manna, Saikat Kumar; Maiti, Kalipada; Mondal, Sanchita; Maji, Rajkishor; Mandal, Debasish; Mandal, Sukhendu; Uddin, Md Raihan; Goswami, Shyamaprosad; Quah, Ching Kheng; Fun, Hoong-Kun

2015-02-21

Azodye-rhodamine hybrid colorimetric fluorescent probe (L) has been designed and synthesized. The structure of L has been established based on single crystal XRD. It has been shown to act as a selective turn-on fluorescent chemosensor for Pd(2+) with >40 fold enhancement by exhibiting red emission among the other 27 cations studied in aqueous ethanol. The coordination features of the species of recognition have been computationally evaluated by DFT methods and found to have a distorted tetrahedral Pd(2+) center in the binding core. The probe (L) has been shown to detect Pd up to 0.45 μM at pH 7.4. Furthermore, the probe can be used to image Pd(2+) in living cells.

A gallery approach for off-angle iris recognition

NASA Astrophysics Data System (ADS)

Karakaya, Mahmut; Yoldash, Rashiduddin; Boehnen, Christopher

2015-05-01

It has been proven that hamming distance score between frontal and off-angle iris images of same eye differs in iris recognition system. The distinction of hamming distance score is caused by many factors such as image acquisition angle, occlusion, pupil dilation, and limbus effect. In this paper, we first study the effect of the angle variations between iris plane and the image acquisition systems. We present how hamming distance changes for different off-angle iris images even if they are coming from the same iris. We observe that increment in acquisition angle of compared iris images causes the increment in hamming distance. Second, we propose a new technique in off-angle iris recognition system that includes creating a gallery of different off-angle iris images (such as, 0, 10, 20, 30, 40, and 50 degrees) and comparing each probe image with these gallery images. We will show the accuracy of the gallery approach for off-angle iris recognition.

Far Western: probing membranes.

PubMed

Einarson, Margret B; Pugacheva, Elena N; Orlinick, Jason R

2007-08-01

INTRODUCTIONThe far-Western technique described in this protocol is fundamentally similar to Western blotting. In Western blots, an antibody is used to detect a query protein on a membrane. In contrast, in a far-Western blot (also known as an overlay assay) the antibody is replaced by a recombinant GST fusion protein (produced and purified from bacteria), and the assay detects the interaction of this protein with target proteins on a membrane. The membranes are washed and blocked, incubated with probe protein, washed again, and subjected to autoradiography. The GST fusion (probe) proteins are often labeled with (32)P; alternatively, the membrane can be probed with unlabeled GST fusion protein, followed by detection using commercially available GST antibodies. The nonradioactive approach is substantially more expensive (due to the purchase of antibody and detection reagents) than using radioactively labeled proteins. In addition, care must be taken to control for nonspecific interactions with GST alone and a signal resulting from antibody cross-reactivity. In some instances, proteins on the membrane are not able to interact after transfer. This may be due to improper folding, particularly in the case of proteins expressed from a phage expression library. This protocol describes a way to overcome this by washing the membrane in denaturation buffer, which is then serially diluted to permit slow renaturation of the proteins.

Accurate multi-robot targeting for keyhole neurosurgery based on external sensor monitoring.

PubMed

Comparetti, Mirko Daniele; Vaccarella, Alberto; Dyagilev, Ilya; Shoham, Moshe; Ferrigno, Giancarlo; De Momi, Elena

2012-05-01

Robotics has recently been introduced in surgery to improve intervention accuracy, to reduce invasiveness and to allow new surgical procedures. In this framework, the ROBOCAST system is an optically surveyed multi-robot chain aimed at enhancing the accuracy of surgical probe insertion during keyhole neurosurgery procedures. The system encompasses three robots, connected as a multiple kinematic chain (serial and parallel), totalling 13 degrees of freedom, and it is used to automatically align the probe onto a desired planned trajectory. The probe is then inserted in the brain, towards the planned target, by means of a haptic interface. This paper presents a new iterative targeting approach to be used in surgical robotic navigation, where the multi-robot chain is used to align the surgical probe to the planned pose, and an external sensor is used to decrease the alignment errors. The iterative targeting was tested in an operating room environment using a skull phantom, and the targets were selected on magnetic resonance images. The proposed targeting procedure allows about 0.3 mm to be obtained as the residual median Euclidean distance between the planned and the desired targets, thus satisfying the surgical accuracy requirements (1 mm), due to the resolution of the diffused medical images. The performances proved to be independent of the robot optical sensor calibration accuracy.

NK1 receptor antagonism and emotional processing in healthy volunteers.

PubMed

Chandra, P; Hafizi, S; Massey-Chase, R M; Goodwin, G M; Cowen, P J; Harmer, C J

2010-04-01

The neurokinin-1 (NK(1)) receptor antagonist, aprepitant, showed activity in several animal models of depression; however, its efficacy in clinical trials was disappointing. There is little knowledge of the role of NK(1) receptors in human emotional behaviour to help explain this discrepancy. The aim of the current study was to assess the effects of a single oral dose of aprepitant (125 mg) on models of emotional processing sensitive to conventional antidepressant drug administration in 38 healthy volunteers, randomly allocated to receive aprepitant or placebo in a between groups double blind design. Performance on measures of facial expression recognition, emotional categorisation, memory and attentional visual-probe were assessed following the drug absorption. Relative to placebo, aprepitant improved recognition of happy facial expressions and increased vigilance to emotional information in the unmasked condition of the visual probe task. In contrast, aprepitant impaired emotional memory and slowed responses in the facial expression recognition task suggesting possible deleterious effects on cognition. These results suggest that while antagonism of NK(1) receptors does affect emotional processing in humans, its effects are more restricted and less consistent across tasks than those of conventional antidepressants. Human models of emotional processing may provide a useful means of assessing the likely therapeutic potential of new treatments for depression.

Enzyme-free homogeneous electrochemical biosensor for DNA assay using toehold-triggered strand displacement reaction coupled with host-guest recognition of Fe3O4@SiO2@β-CD nanocomposites.

PubMed

Jiang, Jingjing; Lin, Xinyi; Ding, Dong; Diao, Guowang

2018-04-17

Taking advantages of the toehold-triggered strand displacement reaction (TSDR) and host-guest interaction of β-cyclodextrin (β-CD), a facile enzyme-free and homogeneous electrochemical sensing strategy was designed for the sensitive assay of target DNA using Fe 3 O 4 @SiO 2 @β-CD nanocomposites and ferrocene-labeled hairpin DNA (H-1) as the capture and electrochemical probes, respectively. Upon addition of target molecule, the initiated TSDR process induced the conformational change of H-1, and subsequently stimulated the dynamic assembly of assist probes (A-1 and A-2) to generate H-1:A-1:A-2 duplex along with the release of target sequence. The released target could drive the next TSDR recycling and finally result in the formation of numerous DNA duplex. After the molecular recognition of Fe 3 O 4 @SiO 2 @β-CD nanocomposites, a large number of duplex were easily separated from the supernatant solution under an external magnetic field, which led to a decreased H-1 concentration in residual solution, concomitant with a remarkable reduction of peak current. Under the optimized conditions, wide linear range (1-5000 pM), low detection limit (0.3 pM), desirable reproducibility, good selectivity, and satisfactory practical analysis were obtained by the combination of the superior recognition capability of β-CD, TSDR-induced signal amplification, and homogeneous electroanalytical method. The proposed detection strategy could offer a universal approach for the monitoring of various biological analytes via the rational design of probe sequences. Copyright © 2018 Elsevier B.V. All rights reserved.

A Plasma Diagnostic Set for the Study of a Variable Specific Impulse Magnetoplasma Rocket

NASA Astrophysics Data System (ADS)

Squire, J. P.; Chang-Diaz, F. R.; Bengtson Bussell, R., Jr.; Jacobson, V. T.; Wootton, A. J.; Bering, E. A.; Jack, T.; Rabeau, A.

1997-11-01

The Advanced Space Propulsion Laboratory (ASPL) is developing a Variable Specific Impulse Magnetoplasma Rocket (VASIMR) using an RF heated magnetic mirror operated asymmetrically. We will describe the initial set of plasma diagnostics and data acquisition system being developed and installed on the VASIMR experiment. A U.T. Austin team is installing two fast reciprocating probes: a quadruple Langmuir and a Mach probe. These measure electron density and temperature profiles, electrostatic plasma fluctuations, and plasma flow profiles. The University of Houston is developing an array of 20 highly directional Retarding Potential Analyzers (RPA) for measuring ion energy distribution function profiles in the rocket plume, giving a measurement of total thrust. We have also developed a CAMAC based data acquisition system using LabView running on a Power Macintosh communicating through a 2 MB/s serial highway. We will present data from initial plasma operations and discuss future diagnostic development.

Supramolecular recognition control of polyethylene glycol modified N-doped graphene quantum dots: tunable selectivity for alkali and alkaline-earth metal ions.

PubMed

Yang, Siwei; Sun, Jing; Zhu, Chong; He, Peng; Peng, Zheng; Ding, Guqiao

2016-02-07

The graphene quantum dot based fluorescent probe community needs unambiguous evidence about the control on the ion selectivity. In this paper, polyethylene glycol modified N-doped graphene quantum dots (PN-GQDs) were synthesized by alkylation reaction between graphene quantum dots and organic halides. We demonstrate the tunable selectivity and sensitivity by controlling the supramolecular recognition through the length and the end group size of the polyether chain on PN-GQDs. The relationship formulae between the selectivity/detection limit and polyether chains are experimentally deduced. The polyether chain length determines the interaction between the PN-GQDs and ions with different ratios of charge to radius, which in turn leads to a good selectivity control. Meanwhile the detection limit shows an exponential growth with the size of end groups of the polyether chain. The PN-GQDs can be used as ultrasensitive and selective fluorescent probes for Li(+), Na(+), K(+), Mg(2+), Ca(2+) and Sr(2+), respectively.

A light-up probe targeting for Bcl-2 2345 G-quadruplex DNA with carbazole TO

NASA Astrophysics Data System (ADS)

Gu, Yingchun; Lin, Dayong; Tang, Yalin; Fei, Xuening; Wang, Cuihong; Zhang, Baolian; Zhou, Jianguo

2018-02-01

As its significant role, the selective recognition of G-quadruplex with specific structures and functions is important in biological and medicinal chemistry. Carbazole derivatives have been reported as a kind of fluorescent probe with many excellent optical properties. In the present study, the fluorescence of the dye (carbazole TO) increased almost 70 fold in the presence of bcl-2 2345 G4 compared to that alone in aqueous buffer condition with almost no fluorescence and 10-30 fold than those in the presence of other DNAs. The binding study results by activity inhibition of G4/Hemin peroxidase experiment, NMR titration and molecular docking simulation showed the high affinity and selectivity to bcl-2 2345 G4 arises from its end-stacking interaction with G-quartet. It is said that a facile approach with excellent sensitive, good selectivity and quick response for bcl-2 2345 G-quadruplex was developed and may be used for antitumor recognition or antitumor agents.

Smart Materials Based on DNA Aptamers: Taking Aptasensing to the Next Level

PubMed Central

Mastronardi, Emily; Foster, Amanda; Zhang, Xueru; DeRosa, Maria C.

2014-01-01

“Smart” materials are an emerging category of multifunctional materials with physical or chemical properties that can be controllably altered in response to an external stimulus. By combining the standard properties of the advanced material with the unique ability to recognize and adapt in response to a change in their environment, these materials are finding applications in areas such as sensing and drug delivery. While the majority of these materials are responsive to physical or chemical changes, a particularly exciting area of research seeks to develop smart materials that are sensitive to specific molecular or biomolecular stimuli. These systems require the integration of a molecular recognition probe specific to the target molecule of interest. The ease of synthesis and labeling, low cost, and stability of DNA aptamers make them uniquely suited to effectively serve as molecular recognition probes in novel smart material systems. This review will highlight current work in the area of aptamer-based smart materials and prospects for their future applications. PMID:24553083

Activity-based probes for the ubiquitin conjugation-deconjugation machinery: new chemistries, new tools, and new insights.

PubMed

Hewings, David S; Flygare, John A; Bogyo, Matthew; Wertz, Ingrid E

2017-05-01

The reversible post-translational modification of proteins by ubiquitin and ubiquitin-like proteins regulates almost all cellular processes, by affecting protein degradation, localization, and complex formation. Deubiquitinases (DUBs) are proteases that remove ubiquitin modifications or cleave ubiquitin chains. Most DUBs are cysteine proteases, which makes them well suited for study by activity-based probes. These DUB probes report on deubiquitinase activity by reacting covalently with the active site in an enzyme-catalyzed manner. They have proven to be important tools to study DUB selectivity and proteolytic activity in different settings, to identify novel DUBs, and to characterize deubiquitinase inhibitors. Inspired by the efficacy of activity-based probes for DUBs, several groups have recently reported probes for the ubiquitin conjugation machinery (E1, E2, and E3 enzymes). Many of these enzymes, while not proteases, also posses active site cysteine residues and can be targeted by covalent probes. In this review, we will discuss how features of the probe (cysteine-reactive group, recognition element, and reporter tag) affect reactivity and suitability for certain experimental applications. We will also review the diverse applications of the current probes, and discuss the need for new probe types to study emerging aspects of ubiquitin biology. © 2017 Federation of European Biochemical Societies.

Anti-signal recognition particle autoantibody ELISA validation and clinical associations.

PubMed

Aggarwal, Rohit; Oddis, Chester V; Goudeau, Danielle; Fertig, Noreen; Metes, Ilinca; Stephens, Chad; Qi, Zengbiao; Koontz, Diane; Levesque, Marc C

2015-07-01

The aim of this study was to develop and validate a quantitative anti-signal recognition particle (SRP) autoantibody serum ELISA in patients with myositis and longitudinal association with myositis disease activity. We developed a serum ELISA using recombinant purified full-length human SRP coated on ELISA plates and a secondary antibody that bound human IgG to detect anti-SRP binding. Protein immunoprecipitation was used as the gold standard for the presence of anti-SRP. Serum samples from three groups were analysed: SRP(+) myositis subjects by immunoprecipitation, SRP(-) myositis subjects by immunoprecipitation and non-myositis controls. The ELISA's sensitivity, specificity, positive predictive value and negative predictive value were evaluated. Percentage agreement and test-retest reliability were assessed. Serial samples from seven SRP immunoprecipitation-positive subjects were also tested, along with serum muscle enzymes and manual muscle testing. Using immunoprecipitation, we identified 26 SRP(+) myositis patients and 77 SRP(-) controls (including 38 patients with necrotizing myopathy). Non-myositis control patients included SLE (n = 4) and SSc (n = 7) patients. Anti-SRP positivity by ELISA showed strong agreement (97.1%) with immunoprecipitation (κ = 0.94). The sensitivity, specificity, positive predictive value, and negative predictive value of the anti-SRP ELISA were 88, 100, 100 and 96, respectively. The area under the curve was 0.94, and test-retest reliability was strong (r = 0.91, P < 0.001). Serial samples showed that anti-SRP levels paralleled changes in muscle enzymes and manual muscle testing. We developed a quantitative ELISA for detecting serum anti-SRP autoantibodies and validated the assay in myositis. Longitudinal assessment of SRP levels by ELISA may be a useful biomarker for disease activity. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Development and implementation of a three-choice serial reaction time task for zebrafish (Danio rerio).

PubMed

Parker, Matthew O; Millington, Mollie E; Combe, Fraser J; Brennan, Caroline H

2012-02-01

Zebrafish are an established and widely utilized developmental genetic model system, but limitations in developed behavioral assays have meant that their potential as a model in behavioral neuroscience has yet to be fully realized. Here, we describe the development of a novel operant behavioral assay to examine a variety of aspects of stimulus control in zebrafish using a 3 choice serial reaction time task (3 CSRTT). Fish were briefly exposed to three spatially distinct, but perceptually identical stimuli, presented in a random order after a fixed-time inter-trial interval (ITI). Entries to the correct response aperture either during the stimulus presentation, or within a brief limited hold period following presentation, were reinforced with illumination of the magazine light and delivery of a small food reward. Following training, premature responding was probed with a long-ITI session three times; once at baseline, once following a saline injection and once following an injection of a low dose of amphetamine (AMPH; 0.025 mg/kg). We predicted that if premature responding was related to impulsivity (as in rodents) it would be reduced following the AMPH injection. Results confirmed that zebrafish could learn to perform a complex operant task similar to tasks developed for rodents which are used to probe sustained attention and impulsivity, but the results from the AMPH trials were inconclusive. This study provides the foundations for development and further validation of this species as a model for some aspects of human attentional and impulse control disorders, such as substance abuse disorder. Copyright © 2011 Elsevier B.V. All rights reserved.

High resolution ultrasonic spectroscopy system for nondestructive evaluation

NASA Technical Reports Server (NTRS)

Chen, C. H.

1991-01-01

With increased demand for high resolution ultrasonic evaluation, computer based systems or work stations become essential. The ultrasonic spectroscopy method of nondestructive evaluation (NDE) was used to develop a high resolution ultrasonic inspection system supported by modern signal processing, pattern recognition, and neural network technologies. The basic system which was completed consists of a 386/20 MHz PC (IBM AT compatible), a pulser/receiver, a digital oscilloscope with serial and parallel communications to the computer, an immersion tank with motor control of X-Y axis movement, and the supporting software package, IUNDE, for interactive ultrasonic evaluation. Although the hardware components are commercially available, the software development is entirely original. By integrating signal processing, pattern recognition, maximum entropy spectral analysis, and artificial neural network functions into the system, many NDE tasks can be performed. The high resolution graphics capability provides visualization of complex NDE problems. The phase 3 efforts involve intensive marketing of the software package and collaborative work with industrial sectors.

Structural insights into the extracellular recognition of the human serotonin 2B receptor by an antibody

PubMed Central

Wacker, Daniel; Kapoor, Mili; Zhang, Ai; Han, Gye Won; Basu, Shibom; Patel, Nilkanth; Messerschmidt, Marc; Weierstall, Uwe; Liu, Wei; Katritch, Vsevolod; Roth, Bryan L.; Stevens, Raymond C.

2017-01-01

Monoclonal antibodies provide an attractive alternative to small-molecule therapies for a wide range of diseases. Given the importance of G protein-coupled receptors (GPCRs) as pharmaceutical targets, there has been an immense interest in developing therapeutic monoclonal antibodies that act on GPCRs. Here we present the 3.0-Å resolution structure of a complex between the human 5-hydroxytryptamine 2B (5-HT2B) receptor and an antibody Fab fragment bound to the extracellular side of the receptor, determined by serial femtosecond crystallography with an X-ray free-electron laser. The antibody binds to a 3D epitope of the receptor that includes all three extracellular loops. The 5-HT2B receptor is captured in a well-defined active-like state, most likely stabilized by the crystal lattice. The structure of the complex sheds light on the mechanism of selectivity in extracellular recognition of GPCRs by monoclonal antibodies. PMID:28716900

A NBD-based simple but effective fluorescent pH probe for imaging of lysosomes in living cells.

PubMed

Cao, Xiang-Jian; Chen, Li-Na; Zhang, Xuan; Liu, Jin-Ting; Chen, Ming-Yu; Wu, Qiu-Rong; Miao, Jun-Ying; Zhao, Bao-Xiang

2016-05-12

NBDlyso with lysosome-locating morpholine moiety has been developed as a high selective and sensitive fluorescent pH probe. This probe can respond to acidic pH (2.0-7.0) in a short time (less than 1 min) and not almost change after continuously illuminated for an extended period by ultraviolet light. The fluorescence intensity of NBDlyso enhanced 100-fold in acidic solution, with very good linear relationship (R(2) = 0.996). The pKa of probe NBDlyso is 4.10. Therefore, NBDlyso was used to detect lysosomal pH changes successfully. Besides, X-ray crystallography was used to verify the structure of NBDlyso, and the recognition mechanism involving photo-induced electron transfer was interpreted theoretically by means of DFT and TDDFT calculations skillfully when NBDlyso comes into play under the acidic condition. This probe showed good ability to sense pH change in living cell image. Copyright © 2016 Elsevier B.V. All rights reserved.

A highly sensitive turn-on fluorescent chemosensor for recognition of Zn2 + and Hg2 + and applications

NASA Astrophysics Data System (ADS)

Tang, Xu; Han, Juan; Wang, Yun; Bao, Xu; Ni, Liang; Wang, Lei; Li, Longhua

2017-09-01

A fluorescence probe has been designed and synthesized, and applied with a combined theoretical and experimental study. Research suggests that the probe can be used to sense Zn2 + and Hg2 + through selective turn-on fluorescence responses in the aqueous HEPES buffer (0.05M, pH = 7.4). The limit of detection (LOD) were determined as 1.46 × 10- 7 M (Zn2 +) and 2.50 × 10- 7 M (Hg2 +). Moreover, based on DFT, the geometry optimizations of probe 1, [1-Hg2 +] complex and [1-Zn2 +] complex were carried out using the Gaussian 09 program, in which the B3LYP function was used. The electronic properties of free probe 1 and the metal complexes were studied based on the Natural Bond Orbital (NBO) analyses. The probe 1 has also been successfully applied to detection of Zn2 + and Hg2 + in living cells.

Illusory conjunctions in visual short-term memory: Individual differences in corpus callosum connectivity and splitting attention between the two hemifields.

PubMed

Qin, Shuo; Ray, Nicholas R; Ramakrishnan, Nithya; Nashiro, Kaoru; O'Connell, Margaret A; Basak, Chandramallika

2016-11-01

Overloading the capacity of visual attention can result in mistakenly combining the various features of an object, that is, illusory conjunctions. We hypothesize that if the two hemispheres separately process visual information by splitting attention, connectivity of corpus callosum-a brain structure integrating the two hemispheres-would predict the degree of illusory conjunctions. In the current study, we assessed two types of illusory conjunctions using a memory-scanning paradigm; the features were either presented across the two opposite hemifields or within the same hemifield. Four objects, each with two visual features, were briefly presented together followed by a probe-recognition and a confidence rating for the recognition accuracy. MRI scans were also obtained. Results indicated that successful recollection during probe recognition was better for across hemifields conjunctions compared to within hemifield conjunctions, lending support to the bilateral advantage of the two hemispheres in visual short-term memory. Age-related differences regarding the underlying mechanisms of the bilateral advantage indicated greater reliance on recollection-based processing in young and on familiarity-based processing in old. Moreover, the integrity of the posterior corpus callosum was more predictive of opposite hemifield illusory conjunctions compared to within hemifield illusory conjunctions, even after controlling for age. That is, individuals with lesser posterior corpus callosum connectivity had better recognition for objects when their features were recombined from the opposite hemifields than from the same hemifield. This study is the first to investigate the role of the corpus callosum in splitting attention between versus within hemifields. © 2016 Society for Psychophysiological Research.

Subject-specific and pose-oriented facial features for face recognition across poses.

PubMed

Lee, Ping-Han; Hsu, Gee-Sern; Wang, Yun-Wen; Hung, Yi-Ping

2012-10-01

Most face recognition scenarios assume that frontal faces or mug shots are available for enrollment to the database, faces of other poses are collected in the probe set. Given a face from the probe set, one needs to determine whether a match in the database exists. This is under the assumption that in forensic applications, most suspects have their mug shots available in the database, and face recognition aims at recognizing the suspects when their faces of various poses are captured by a surveillance camera. This paper considers a different scenario: given a face with multiple poses available, which may or may not include a mug shot, develop a method to recognize the face with poses different from those captured. That is, given two disjoint sets of poses of a face, one for enrollment and the other for recognition, this paper reports a method best for handling such cases. The proposed method includes feature extraction and classification. For feature extraction, we first cluster the poses of each subject's face in the enrollment set into a few pose classes and then decompose the appearance of the face in each pose class using Embedded Hidden Markov Model, which allows us to define a set of subject-specific and pose-priented (SSPO) facial components for each subject. For classification, an Adaboost weighting scheme is used to fuse the component classifiers with SSPO component features. The proposed method is proven to outperform other approaches, including a component-based classifier with local facial features cropped manually, in an extensive performance evaluation study.

A Highly Sensitive Fluorogenic Probe for Imaging Glycoproteins and Mucine Activity in Live Cells in the Near-Infrared Region.

PubMed

Samaniego Lopez, Cecilia; Hebe Martínez, Jimena; Uhrig, María Laura; Coluccio Leskow, Federico; Spagnuolo, Carla Cecilia

2018-04-25

A novel fluorescent molecular probe is reported, which is able to detect glycoproteins, especially mucins, with high sensitivity and with a turn-on response along with a large Stokes shift (>130 nm), within the biologically active window. The probe contains an aminotricarbocyanine as the fluorescent reporter with a linked benzoboroxole as the recognition unit, which operates through a dynamic covalent reaction between the boronic hemiester residue of the receptor and cis-diols of the analyte. The superior selectivity of the probe is displayed by the labeling of mucins present in Calu-3 cells. The new benzoboroxole fluorescent derivative gathers together key properties to make it a highly rated molecular probe: specificity, excellent solubility in water, and off-on near infrared emission. This probe is expected to be an excellent tool for imaging intracellular mucin to evaluate mucus-related diseases as well as a sensing strategy towards glycosylated structures with a high potential for theranostics approaches in biological samples. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Poly-adenine-mediated fluorescent spherical nucleic acid probes for live-cell imaging of endogenous tumor-related mRNA.

PubMed

Zhu, Dan; Zhao, Dongxia; Huang, Jiaxuan; Zhu, Yu; Chao, Jie; Su, Shao; Li, Jiang; Wang, Lihua; Shi, Jiye; Zuo, Xiaolei; Weng, Lixing; Li, Qian; Wang, Lianhui

2018-05-16

Identification of tumor-related mRNA in living cells hold great promise for early cancer diagnosis and pathological research. Herein, we present poly-adenine (polyA)-mediated fluorescent spherical nucleic acid (FSNA) probes for intracellular mRNA detection with regulable sensitivities by programmably adjusting the loading density of DNA on gold nano-interface. Gold nanoparticles (AuNPs) functionalized with polyA-tailed recognition sequences were hybridized to fluorescent "reporter" strands to fabricate fluorescence-quenched FSNA probes. While exposed to target gene, the "reporter" strands were released from FSNA through strand displacement and fluorescence was recovered. With polyA20 tail as the attaching block, the detection limit of FSNA probes was calculated to be 0.31 nM, which is ~55 fold lower than that of thiolated probes without surface density regulation. Quantitative intracellular mRNA detection and imaging could be achieved with polyA-mediated FSNA probes within 2 hours, indicating their application potential in rapid and sensitive intracellular target imaging. Copyright © 2018. Published by Elsevier Inc.

Differentiating RNA from DNA by a molecular fluorescent probe based on the "door-bolt" mechanism biomaterials.

PubMed

Yao, Qichao; Li, Haidong; Xian, Liman; Xu, Feng; Xia, Jing; Fan, Jiangli; Du, Jianjun; Wang, Jingyun; Peng, Xiaojun

2018-09-01

Although excellent florescent probes have been developed for DNA, good probes for RNA remain lacking. The shortage of reported and commercial RNA probes is attributable to their severe interference from DNA. As DNA and RNA have similar structures but different functions, it has been an imperative challenge to develop RNA probes that differentiate from DNA. In this study, an NIR fluorescent probe, NBE, is described, which contains a bulky julolidine group that can fit in a spacious RNA pocket and emit intense fluorescence. However, NBE has no response to DNA, as it cannot intercalate into the double strands or even in the DNA minor groove. The sensing mechanism is similar to the effect of a door-bolt. NBE shows excellent performance in RNA sensing (outstanding photostability, high selectivity and fast response), whether in aqueous buffers, fixed cells or living cells. These findings might provide not only a potential imaging tool but also a new design strategy for the recognition of RNA while avoiding interference from DNA. Copyright © 2018 Elsevier Ltd. All rights reserved.

A new fluorescent probe for distinguishing Zn2+ and Cd2+ with high sensitivity and selectivity.

PubMed

Tan, Yiqun; Gao, Junkuo; Yu, Jiancan; Wang, Ziqi; Cui, Yuanjing; Yang, Yu; Qian, Guodong

2013-08-28

A new fluorescence probe for distinguishing Zn(2+) and Cd(2+) is designed and synthesized. For the first time to our knowledge, this probe can recognize similar metal ions by coherently utilizing intramolecular charge transfer (ICT) and different electronic affinities of various metal ions, instead of by selective coordination alone, which may be interfered with and lose its selectivity easily in a complicated environment, providing a distinct recognition even by the naked eye for Zn(2+) and Cd(2+) with the sensitivity at the ppb level. This design strategy may initiate a straightforward approach for the selective detection of various metal ions with similar chemical properties in extensive applications such as environmental, industrial, and bio-science.

Highly selective on-off fluorescence recognition of Fe3+ based on a coumarin derivative and its application in live-cell imaging

NASA Astrophysics Data System (ADS)

Warrier, Sona; Kharkar, Prashant S.

2018-01-01

A novel coumarin chemosensor, 7-hydroxy-2-oxo-N-(pyridin-2-ylmethyl)chromene-3-carboxamide (Probe 1), demonstrated significant selectivity towards Fe3+ ions. Probe 1 exhibited high fluorescence emission profile at 447 nm, excellent selectivity towards Fe3+ over other biologically important metal ions (Al3+, Ba2+, Co2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+ and Sn2+). Interestingly, there was 30-fold decrease in fluorescence intensity upon Fe3+ binding. The limit of detection of Fe3+ was found to be 0.76 μM ( 40 ppb). Probe 1 also exhibited high potential as an intracellular chemosensor for Fe3+.

Real-time detection of caspase-2 activation in a single living HeLa cell during cisplatin-induced apoptosis

NASA Astrophysics Data System (ADS)

Lin, Juqiang; Zhang, Zhihong; Yang, Jie; Zeng, Shaoqun; Liu, Bifeng; Luo, Qingming

2006-03-01

Caspase-2 is important for the mitochondrial apoptotic pathway, however, the mechanism by which caspase-2 executes apoptosis remains obscure. We carry out the first measurements of the dynamics of caspase-2 activation in a single living cell by a FRET (fluorescence resonance energy transfer) probe. Two FRET probes are constructed that each encoded a CRS (caspase-2 or caspase-3 recognition site) fused with a cyan fluorescent protein (CFP) and a red fluorescent protein (DsRed) (CFP-CRS-DsRed). Using these probes, we found that during cisplatin-induced apoptosis, caspase-2 activation occurred more slowly than did activation of caspase-3; additionally, caspase-2 activation was initiated much earlier than that of caspase-3.

Orthogonal Patterns In A Binary Neural Network

NASA Technical Reports Server (NTRS)

Baram, Yoram

1991-01-01

Report presents some recent developments in theory of binary neural networks. Subject matter relevant to associate (content-addressable) memories and to recognition of patterns - both of considerable importance in advancement of robotics and artificial intelligence. When probed by any pattern, network converges to one of stored patterns.

Combining functionalised nanoparticles and SERS for the detection of DNA relating to disease.

PubMed

Graham, Duncan; Stevenson, Ross; Thompson, David G; Barrett, Lee; Dalton, Colette; Faulds, Karen

2011-01-01

DNA functionalised nanoparticle probes offer new opportunities in analyte detection. Ultrasensitive, molecularly specific targeting of analytes is possible through the use of metallic nanoparticles and their ability to generate a surface enhanced Raman scattering (SERS) response. This is leading to a new range of diagnostic clinical probes based on SERS detection. Our approaches have shown how such probes can detect specific DNA sequences by using a biomolecular recognition event to 'turn on' a SERS response through a controlled assembly process of the DNA functionalised nanoparticles. Further, we have prepared DNA aptamer functionalised SERS probes and demonstrated how introduction of a protein target can change the aggregation state of the nanoparticles in a dose-dependant manner. These approaches are being used as methods to detect biomolecules that indicate a specific disease being present with a view to improving disease management.

Recent Advances in Macrocyclic Fluorescent Probes for Ion Sensing.

PubMed

Wong, Joseph K-H; Todd, Matthew H; Rutledge, Peter J

2017-01-25

Small-molecule fluorescent probes play a myriad of important roles in chemical sensing. Many such systems incorporating a receptor component designed to recognise and bind a specific analyte, and a reporter or transducer component which signals the binding event with a change in fluorescence output have been developed. Fluorescent probes use a variety of mechanisms to transmit the binding event to the reporter unit, including photoinduced electron transfer (PET), charge transfer (CT), Förster resonance energy transfer (FRET), excimer formation, and aggregation induced emission (AIE) or aggregation caused quenching (ACQ). These systems respond to a wide array of potential analytes including protons, metal cations, anions, carbohydrates, and other biomolecules. This review surveys important new fluorescence-based probes for these and other analytes that have been reported over the past five years, focusing on the most widely exploited macrocyclic recognition components, those based on cyclam, calixarenes, cyclodextrins and crown ethers; other macrocyclic and non-macrocyclic receptors are also discussed.

A new simple phthalimide-based fluorescent probe for highly selective cysteine and bioimaging for living cells

NASA Astrophysics Data System (ADS)

Shen, Youming; Zhang, Xiangyang; Zhang, Youyu; Zhang, Chunxiang; Jin, Junling; Li, Haitao

2017-10-01

A new turn-on phthalimide fluorescent probe has designed and synthesized for sensing cysteine (Cys) based on excited state intramolecular proton transfer (ESIPT) process. It is consisted of a 3-hydroxyphthalimide derivative moiety as the fluorophore and an acrylic ester group as a recognition receptor. The acrylic ester acts as an ESIPT blocking agent. Upon addition of cystein, intermolecular nucleophilic attack of cysteine on acrylic ester releases the fluorescent 3-hydroxyphthalimide derivative, thereby enabling the ESIPT process and leading to enhancement of fluorescence. The probe displays high sensitivity, excellent selectivity and with large Stokes shift toward cysteine. The linear interval range of the fluorescence titration ranged from 0 to 1.0 × 10- 5 M and detection limit is low (6 × 10- 8 M). In addition, the probe could be used for bio-imaging in living cells.

Sensitive fluorescence detection of nucleic acids based on isothermal circular strand-displacement polymerization reaction.

PubMed

Guo, Qiuping; Yang, Xiaohai; Wang, Kemin; Tan, Weihong; Li, Wei; Tang, Hongxing; Li, Huimin

2009-02-01

Here we have developed a sensitive DNA amplified detection method based on isothermal strand-displacement polymerization reaction. This method takes advantage of both the hybridization property of DNA and the strand-displacement property of polymerase. Importantly, we demonstrate that our method produces a circular polymerization reaction activated by the target, which essentially allows it to self-detect. Functionally, this DNA system consists of a hairpin fluorescence probe, a short primer and polymerase. Upon recognition and hybridization with the target ssDNA, the stem of the hairpin probe is opened, after which the opened probe anneals with the primer and triggers the polymerization reaction. During this process of the polymerization reaction, a complementary DNA is synthesized and the hybridized target is displaced. Finally, the displaced target recognizes and hybridizes with another probe, triggering the next round of polymerization reaction, reaching a target detection limit of 6.4 x 10(-15) M.

Selective recognition of DNA from olive leaves and olive oil by PNA and modified-PNA microarrays

PubMed Central

Rossi, Stefano; Calabretta, Alessandro; Tedeschi, Tullia; Sforza, Stefano; Arcioni, Sergio; Baldoni, Luciana; Corradini, Roberto; Marchelli, Rosangela

2012-01-01

PNA probes for the specific detection of DNA from olive oil samples by microarray technology were developed. The presence of as low as 5% refined hazelnut (Corylus avellana) oil in extra-virgin olive oil (Olea europaea L.) could be detected by using a PNA microarray. A set of two single nucleotide polymorphisms (SNPs) from the Actin gene of Olive was chosen as a model for evaluating the ability of PNA probes for discriminating olive cultivars. Both unmodified and C2-modified PNAs bearing an arginine side-chain were used, the latter showing higher sequence specificity. DNA extracted from leaves of three different cultivars (Ogliarola leccese, Canino and Frantoio) could be easily discriminated using a microarray with unmodified PNA probes, whereas discrimination of DNA from oil samples was more challenging, and could be obtained only by using chiral PNA probes. PMID:22772038

Diketopyrrolopyrrole: brilliant red pigment dye-based fluorescent probes and their applications.

PubMed

Kaur, Matinder; Choi, Dong Hoon

2015-01-07

The development of fluorescent probes for the detection of biologically relevant species is a burgeoning topic in the field of supramolecular chemistry. A number of available dyes such as rhodamine, coumarin, fluorescein, and cyanine have been employed in the design and synthesis of new fluorescent probes. However, diketopyrrolopyrrole (DPP) and its derivatives have a distinguished role in supramolecular chemistry for the design of fluorescent dyes. DPP dyes offer distinctive advantages relative to other organic dyes, including high fluorescence quantum yields and good light and thermal stability. Significant advancements have been made in the development of new fluorescent probes based on DPP in recent years as a result of tireless research efforts by the chemistry scientific community. In this tutorial review, we highlight the recent progress in the development of DPP-based fluorescent probes for the period spanning 2009 to the present time and the applications of these probes to recognition of biologically relevant species including anions, cations, reactive oxygen species, thiols, gases and other miscellaneous applications. This review is targeted toward providing the readers with deeper understanding for the future design of DPP-based fluorogenic probes for chemical and biological applications.

A novel and simple fluorescence probe for detecting main group magnesium ion in HeLa cells and Arabidopsis.

PubMed

Yu, Tingting; Sun, Ping; Hu, Yijie; Ji, Yinggang; Zhou, Hongping; Zhang, Baowei; Tian, Yupeng; Wu, Jieying

2016-12-15

A simple-molecule fluorescence probe L has been designed, synthesized and characterized, which shows high selectivity and sensitivity for the main group magnesium ion through fluorescence "turn-on" response in ethanol solution, and no interference from calcium ion in particular. Detection limit of probe L is 1.47×10(-6) M and the rapid response could reach about 15-20s. The recognition mechanism has been established by fluorescence spectra, (1)H NMR study. Moreover, probe L presents a great photostability, low toxicity and cellular permeability, then we have carried out fluorescent bio-imaging of the probe L for magnesium ions in HeLa cells, which showed that probe L could be utilized to detect the intracellular magnesium ion. Furthermore, it is successfully used as a magnesium ion developer in plant tissues, which shows that it not only can be well tracking the transport of magnesium ion but also make a corresponding fluorescence response to different concentrations magnesium ion. These results would make this probe a great potential application for detecting Mg(2+) in biological system. Copyright © 2016 Elsevier B.V. All rights reserved.

Pyrazolone as a recognition site: Rhodamine 6G-based fluorescent probe for the selective recognition of Fe3+ in acetonitrile-aqueous solution.

PubMed

Parihar, Sanjay; Boricha, Vinod P; Jadeja, R N

2015-03-01

Two novel Rhodamine-pyrazolone-based colorimetric off-on fluorescent chemosensors for Fe(3+) ions were designed and synthesized using pyrazolone as the recognition moiety and Rhodamine 6G as the signalling moiety. The photophysical properties and Fe(3+) -binding properties of sensors L(1) and L(2) in acetonitrile-aqueous solution were also investigated. Both sensors successfully exhibit a remarkably 'turn-on' response, toward Fe(3+) , which was attributed to 1: 2 complex formation between Fe(3+) and L(1) /L(2) . The fluorescent and colorimetric response to Fe(3+) can be detected by the naked eye, which provides a facile method for the visual detection of Fe(3+) . Copyright © 2014 John Wiley & Sons, Ltd.

A Label-Free and Sensitive Fluorescent Qualitative Assay for Bisphenol A Based on Rolling Circle Amplification/Exonuclease III-Combined Cascade Amplification.

PubMed

Li, Xia; Song, Juan; Xue, Qing-Wang; You, Fu-Heng; Lu, Xia; Kong, Yan-Cong; Ma, Shu-Yi; Jiang, Wei; Li, Chen-Zhong

2016-10-21

Bisphenol A (BPA) detection in drinking water and food packaging materials has attracted much attention since the discovery that BPA can interfere with normal physiological processes and cause adverse health effects. Here, we constructed a label-free aptamer fluorescent assay for selective and sensitive detection of BPA based on the rolling circle amplification (RCA)/Exonuclease III (Exo III)-combined cascade amplification strategy. First, the duplex DNA probe (RP) with anti-BPA aptamer and trigger sequence was designed for BPA recognition and signal amplification. Next, under the action of BPA, the trigger probe was liberated from RP to initiate RCA reaction as primary amplification. Subsequently, the RCA products were used to trigger Exo III assisted secondary amplification with the help of hairpin probes, producing plenty of "G-quadruplex" in lantern-like structures. Finally, the continuously enriched "G-quadruplex lanterns" were lightened by zinc(II)-protoporphyrin IX (ZnPPIX) generating enhanced fluorescence signals. By integrating the primary RCA and secondary Exo III mediated cascade amplification strategy, this method displayed an excellent sensitivity with the detection limits of 5.4 × 10 -17 M. In addition, the anti-BPA aptamer exhibits high recognition ability with BPA, guaranteeing the specificity of detection. The reporter signal probe (G-quadruplex with ZnPPIX) provides a label-free fluorescence signals readout without complicated labeling procedures, making the method simple in design and cost-effective in operation. Moreover, environmental samples analysis was also performed, suggesting that our strategy was reliable and had a great potential application in environmental monitoring.

A Label-Free and Sensitive Fluorescent Qualitative Assay for Bisphenol A Based on Rolling Circle Amplification/Exonuclease III-Combined Cascade Amplification

PubMed Central

Li, Xia; Song, Juan; Xue, Qing-Wang; You, Fu-Heng; Lu, Xia; Kong, Yan-Cong; Ma, Shu-Yi; Jiang, Wei; Li, Chen-Zhong

2016-01-01

Bisphenol A (BPA) detection in drinking water and food packaging materials has attracted much attention since the discovery that BPA can interfere with normal physiological processes and cause adverse health effects. Here, we constructed a label-free aptamer fluorescent assay for selective and sensitive detection of BPA based on the rolling circle amplification (RCA)/Exonuclease III (Exo III)-combined cascade amplification strategy. First, the duplex DNA probe (RP) with anti-BPA aptamer and trigger sequence was designed for BPA recognition and signal amplification. Next, under the action of BPA, the trigger probe was liberated from RP to initiate RCA reaction as primary amplification. Subsequently, the RCA products were used to trigger Exo III assisted secondary amplification with the help of hairpin probes, producing plenty of “G-quadruplex” in lantern-like structures. Finally, the continuously enriched “G-quadruplex lanterns” were lightened by zinc(II)-protoporphyrin IX (ZnPPIX) generating enhanced fluorescence signals. By integrating the primary RCA and secondary Exo III mediated cascade amplification strategy, this method displayed an excellent sensitivity with the detection limits of 5.4 × 10−17 M. In addition, the anti-BPA aptamer exhibits high recognition ability with BPA, guaranteeing the specificity of detection. The reporter signal probe (G-quadruplex with ZnPPIX) provides a label-free fluorescence signals readout without complicated labeling procedures, making the method simple in design and cost-effective in operation. Moreover, environmental samples analysis was also performed, suggesting that our strategy was reliable and had a great potential application in environmental monitoring. PMID:28335318

Thermodynamic basis for engineering high-affinity, high-specificity binding-induced DNA clamp nanoswitches.

PubMed

Idili, Andrea; Plaxco, Kevin W; Vallée-Bélisle, Alexis; Ricci, Francesco

2013-12-23

Naturally occurring chemoreceptors almost invariably employ structure-switching mechanisms, an observation that has inspired the use of biomolecular switches in a wide range of artificial technologies in the areas of diagnostics, imaging, and synthetic biology. In one mechanism for generating such behavior, clamp-based switching, binding occurs via the clamplike embrace of two recognition elements onto a single target molecule. In addition to coupling recognition with a large conformational change, this mechanism offers a second advantage: it improves both affinity and specificity simultaneously. To explore the physics of such switches we have dissected here the thermodynamics of a clamp-switch that recognizes a target DNA sequence through both Watson-Crick base pairing and triplex-forming Hoogsteen interactions. When compared to the equivalent linear DNA probe (which relies solely on Watson-Crick interactions), the extra Hoogsteen interactions in the DNA clamp-switch increase the probe's affinity for its target by ∼0.29 ± 0.02 kcal/mol/base. The Hoogsteen interactions of the clamp-switch likewise provide an additional specificity check that increases the discrimination efficiency toward a single-base mismatch by 1.2 ± 0.2 kcal/mol. This, in turn, leads to a 10-fold improvement in the width of the "specificity window" of this probe relative to that of the equivalent linear probe. Given these attributes, clamp-switches should be of utility not only for sensing applications but also, in the specific field of DNA nanotechnology, for applications calling for a better control over the building of nanostructures and nanomachines.

Cucurbituril mediated single molecule detection and identification via recognition tunneling.

PubMed

Xiao, Bohuai; Liang, Feng; Liu, Simin; Im, JongOne; Li, Yunchuan; Liu, Jing; Zhang, Bintian; Zhou, Jianghao; He, Jin; Chang, Shuai

2018-06-08

Recognition tunneling (RT) is an emerging technique for investigating single molecules in a tunnel junction. We have previously demonstrated its capability of single molecule detection and identification, as well as probing the dynamics of intermolecular bonding at the single molecule level. Here by introducing cucurbituril as a new class of recognition molecule, we demonstrate a powerful platform for electronically investigating the host-guest chemistry at single molecule level. In this report, we first investigated the single molecule electrical properties of cucurbituril in a tunnel junction. Then we studied two model guest molecules, aminoferrocene and amantadine, which were encapsulated by cucurbituril. Small differences in conductance and lifetime can be recognized between the host-guest complexes with the inclusion of different guest molecules. By using a machine learning algorithm to classify the RT signals in a hyper dimensional space, the accuracy of guest molecule recognition can be significantly improved, suggesting the possibility of using cucurbituril molecule for single molecule identification. This work enables a new class of recognition molecule for RT technique and opens the door for detecting a vast variety of small molecules by electrical measurements.

Resolution extension by image summing in serial femtosecond crystallography of two-dimensional membrane-protein crystals

DOE PAGES

Casadei, Cecilia M.; Tsai, Ching-Ju; Barty, Anton; ...

2018-01-01

Previous proof-of-concept measurements on single-layer two-dimensional membrane-protein crystals performed at X-ray free-electron lasers (FELs) have demonstrated that the collection of meaningful diffraction patterns, which is not possible at synchrotrons because of radiation-damage issues, is feasible. Here, the results obtained from the analysis of a thousand single-shot, room-temperature X-ray FEL diffraction images from two-dimensional crystals of a bacteriorhodopsin mutant are reported in detail. The high redundancy in the measurements boosts the intensity signal-to-noise ratio, so that the values of the diffracted intensities can be reliably determined down to the detector-edge resolution of 4 Å. The results show that two-dimensional serial crystallography atmore » X-ray FELs is a suitable method to study membrane proteins to near-atomic length scales at ambient temperature. The method presented here can be extended to pump–probe studies of optically triggered structural changes on submillisecond timescales in two-dimensional crystals, which allow functionally relevant large-scale motions that may be quenched in three-dimensional crystals.« less

Resolution extension by image summing in serial femtosecond crystallography of two-dimensional membrane-protein crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Casadei, Cecilia M.; Tsai, Ching-Ju; Barty, Anton

Previous proof-of-concept measurements on single-layer two-dimensional membrane-protein crystals performed at X-ray free-electron lasers (FELs) have demonstrated that the collection of meaningful diffraction patterns, which is not possible at synchrotrons because of radiation-damage issues, is feasible. Here, the results obtained from the analysis of a thousand single-shot, room-temperature X-ray FEL diffraction images from two-dimensional crystals of a bacteriorhodopsin mutant are reported in detail. The high redundancy in the measurements boosts the intensity signal-to-noise ratio, so that the values of the diffracted intensities can be reliably determined down to the detector-edge resolution of 4 Å. The results show that two-dimensional serial crystallography atmore » X-ray FELs is a suitable method to study membrane proteins to near-atomic length scales at ambient temperature. The method presented here can be extended to pump–probe studies of optically triggered structural changes on submillisecond timescales in two-dimensional crystals, which allow functionally relevant large-scale motions that may be quenched in three-dimensional crystals.« less

Association of physical fitness and fatness with cognitive function in women with fibromyalgia.

PubMed

Soriano-Maldonado, Alberto; Artero, Enrique G; Segura-Jiménez, Víctor; Aparicio, Virgina A; Estévez-López, Fernando; Álvarez-Gallardo, Inmaculada C; Munguía-Izquierdo, Diego; Casimiro-Andújar, Antonio J; Delgado-Fernández, Manuel; Ortega, Francisco B

2016-09-01

This study assessed the association of fitness and fatness with cognitive function in women with fibromyalgia, and the independent influence of their single components on cognitive tasks. A total of 468 women with fibromyalgia were included. Speed of information processing and working memory (Paced Auditory Serial Addition Task), as well as immediate and delayed recall, verbal learning and delayed recognition (Rey Auditory Verbal Learning Test) were assessed. Aerobic fitness, muscle strength, flexibility and motor agility were assessed with the Senior Fitness Test battery. Body mass index, percent body fat, fat-mass index and waist circumference were measured. Aerobic fitness was associated with attention and working memory (all, p < 0.05). All fitness components were generally associated with delayed recall, verbal learning and delayed recognition (all, p < 0.05). Aerobic fitness showed the most powerful association with attention, working memory, delayed recall and verbal learning, while motor agility was the most powerful indicator of delayed recognition. None of the fatness parameters were associated with any of the outcomes (all, p > 0.05). Our results suggest that fitness, but not fatness, is associated with cognitive function in women with fibromyalgia. Aerobic fitness appears to be the most powerful fitness component regarding the cognitive tasks evaluated.

Attention and Encoding in Physics Learning and Problem Solving

ERIC Educational Resources Information Center

Feil, Adam John

2009-01-01

This dissertation presents several studies designed to probe the mental representations that physics experts and novices form when interacting with typical instructional materials, such as diagrams and problem statements. By using recognition tasks and a change detection task, the mental representations of experts and novices are studied in a more…

Cognitive Processing in Oral and Silent Reading Comprehension.

ERIC Educational Resources Information Center

Salasoo, Aita

1986-01-01

Reading rates and comprehension measures that probed recognition of various levels of text structure were collected for passages read orally and silently by 16 college students. Results showed that memory traces of text microstructure created in oral reading were accessed faster during memory-based comprehension tasks than traces established by…

Resolution of localized chronic periodontitis associated with longstanding calculus deposits.

PubMed

Lai, Pin-Chuang; Walters, John D

2014-01-01

This report, which is based on nonstandardized serial radiographs obtained over a period of 15 years, documents a case of localized chronic periodontitis associated with progressive deposition of calculus on the distal aspect of a mandibular second molar. The site was treated by scaling and root planing, followed by a course of adjunctive systemic azithromycin. Treatment yielded favorable reductions in probing depth and clinical inflammation, leaving only few isolated sites with pockets no deeper than 4 mm. Two years after completion of active treatment, there was radiographic evidence of increased bone density distal to the second molar.

Comparison of Double-Freeze versus Modified Triple-Freeze Pulmonary Cryoablation and Hemorrhage Volume Using Different Probe Sizes in an In Vivo Porcine Lung.

PubMed

Pan, Patrick J; Bansal, Anshuman K; Genshaft, Scott J; Kim, Grace H; Suh, Robert D; Abtin, Fereidoun

2018-05-01

To determine size of ablation zone and pulmonary hemorrhage in double-freeze (DF) vs modified triple-freeze (mTF) cryoablation protocols with different probe sizes in porcine lung. In 10 healthy adult pigs, 20 pulmonary cryoablations were performed using either a 2.4-mm or a 1.7-mm probe. Either conventional DF or mTF protocol was used. Serial noncontrast CT scans were performed during ablations. Ablation iceball and hemorrhage volumes were measured and compared between protocols and probe sizes. With 1.7-mm probe, greater peak iceball volume was observed with DF compared with mTF, although difference was not statistically significant (16.1 mL ± 1.9 vs 8.8 mL ± 3.6, P = .07). With 2.4-mm probe, DF and mTF produced similar peak iceball volumes (14.0 mL ± 2.8 vs 14.6 mL ± 2.7, P = .88). Midcycle hemorrhage was significantly larger with DF with the 1.7-mm probe (94.3 mL ± 22.2 vs 19.6 mL ± 2.1, P = .02) and with both sizes combined (93.2 mL ± 17.5 vs. 50.9 mL ± 12.6, P = .048). Rate of hemorrhage increase was significantly higher in DF (10.4 mL/min vs 5.1 mL/min, P = .003). End-cycle hemorrhage was visibly larger in DF compared with mTF across probe sizes, although differences were not statistically significant (P = .14 for 1.7 mm probe, P = .18 for 2.4 mm probe, and P = .07 for both probes combined). Rate of increase in hemorrhage during the last thaw period was not statistically different between DF and mTF (3.0 mL/min vs 2.8 mL/min, P = .992). mTF reduced rate of midcycle hemorrhage compared with DF. With mTF, midcycle hemorrhage was significantly smaller with 1.7-mm probe; although noticeably smaller with 2.4-mm probe, statistical significance was not achieved. Iceball size was not significantly different across both protocols and probe types. Copyright © 2017 SIR. Published by Elsevier Inc. All rights reserved.

Interference from retrieval cues in Parkinson's disease.

PubMed

Crescentini, Cristiano; Marin, Dario; Del Missier, Fabio; Biasutti, Emanuele; Shallice, Tim

2011-11-01

Existing studies on memory interference in Parkinson's disease (PD) patients have provided mixed results and it is unknown whether PD patients have problems in overcoming interference from retrieval cues. We investigated this issue by using a part-list cuing paradigm. In this paradigm, after the study of a list of items, the presentation of some of these items as retrieval cues hinders the recall of the remaining ones. We tested PD patients' (n = 19) and control participants' (n = 16) episodic memory in the presence and absence of part-list cues, using initial-letter probes, and following either weak or strong serial associative encoding of list items. Both PD patients and control participants showed a comparable and significant part-list cuing effect after weak associative encoding (13% vs. 12% decrease in retrieval in part-list cuing vs. no part-list cuing -control- conditions in PD patients and control participants, respectively), denoting a similar effect of cue-driven interference in the two populations when a serial retrieval strategy is hard to develop. However, only PD patients showed a significant part-list cuing effect after strong associative encoding (20% vs. 5% decrease in retrieval in patients and controls, respectively). When encoding promotes the development of an effective serial retrieval strategy, the presentation of part-list cues has a specifically disruptive effect in PD patients. This indicates problems in strategic retrieval, probably related to PD patients' increased tendency to rely on external cues. Findings in control conditions suggest that less effective encoding may have contributed to PD patients' memory performance.

A novel design of a scanning probe microscope integrated with an ultramicrotome for serial block-face nanotomography

NASA Astrophysics Data System (ADS)

Efimov, Anton E.; Agapov, Igor I.; Agapova, Olga I.; Oleinikov, Vladimir A.; Mezin, Alexey V.; Molinari, Michael; Nabiev, Igor; Mochalov, Konstantin E.

2017-02-01

We present a new concept of a combined scanning probe microscope (SPM)/ultramicrotome apparatus. It enables "slice-and-view" scanning probe nanotomography measurements and 3D reconstruction of the bulk sample nanostructure from series of SPM images after consecutive ultrathin sections. The sample is fixed on a flat XYZ scanning piezostage mounted on the ultramicrotome arm. The SPM measuring head with a cantilever tip and a laser-photodiode tip detection system approaches the sample for SPM measurements of the block-face surface immediately after the ultramicrotome sectioning is performed. The SPM head is moved along guides that are also fixed on the ultramicrotome arm. Thereby, relative dysfunctional displacements of the tip, the sample, and the ultramicrotome knife are minimized. The design of the SPM head enables open frontal optical access to the sample block-face adapted for high-resolution optical lenses for correlative SPM/optical microscopy applications. The new system can be used in a wide range of applications for the study of 3D nanostructures of biological objects, biomaterials, polymer nanocomposites, and nanohybrid materials in various SPM and optical microscopy measuring modes.

MUC-1 aptamer-conjugated dye-doped silica nanoparticles for MCF-7 cells detection.

PubMed

Cai, Li; Chen, Ze-Zhong; Chen, Min-Yan; Tang, Hong-Wu; Pang, Dai-Wen

2013-01-01

In this work, we have prepared three types of aptamer-conjugated Rubpy-doped silica nanoparticles for Human breast carcinoma MCF-7 cells labeling. Probe A is prepared through covalent conjugation between amine-labeled MUC-1 aptamer and carboxyl-modified Rubpy-doped NPs (NPs-aptamer). Probe B is prepared based on the interaction between biotin-labeled MUC-1 aptamer and avidin-conjugated Rubpy-doped NPs (NPs-avidin-biotin-aptamer). For Probe C, there is a PEG with flexible long chain as the bridge between avidin and the NPs (NPs-PEG-avidin-biotin-aptamer). In addition, we further investigate the practical number of MUC-1 aptamers on an NP of each probe using hoechst33258 dye. The binding efficiency of MUC-1 aptamer on the three types of probes as follows: Probe A < Probe B < Probe C. In addition, microscopic fluorescence imaging shows that Probe C containing the PEG molecules can be effectively applied for the recognition of MUC-1 protein in human breast carcinoma MCF-7 cells thus demonstrates that the PEG with flexible long chain as the bridge between the aptamer and NP can greatly enhances the freedom of MUC-1 aptamer. Compared with common organic dyes, the dye-doped silica nanoparticles serve as a stable bioprobe because of their facile conjugation with the desirable biomolecules, and have exhibited great potential in bioanalysis. Copyright © 2012 Elsevier Ltd. All rights reserved.

Highly selective SERS probe for Hg(II) detection using tryptophan-protected popcorn shaped gold nanoparticles.

PubMed

Senapati, Tapas; Senapati, Dulal; Singh, Anant Kumar; Fan, Zhen; Kanchanapally, Rajashekhar; Ray, Paresh Chandra

2011-10-07

Contamination of the environment with toxic Hg(II) is becoming a huge concern throughout the world now. Driven by the need, this communication reports for the first time a tryptophan protected popcorn shaped gold nanomaterials based SERS probe for rapid, easy and highly selective recognition of Hg(II) ions in the 5 ppb level from aqueous solution, with high sensitivity and selectivity over competing analytes. We demonstrate that our SERS assay is capable of measuring the amount of Hg(II) in alkaline battery. This journal is © The Royal Society of Chemistry 2011

Robust Point Set Matching for Partial Face Recognition.

PubMed

Weng, Renliang; Lu, Jiwen; Tan, Yap-Peng

2016-03-01

Over the past three decades, a number of face recognition methods have been proposed in computer vision, and most of them use holistic face images for person identification. In many real-world scenarios especially some unconstrained environments, human faces might be occluded by other objects, and it is difficult to obtain fully holistic face images for recognition. To address this, we propose a new partial face recognition approach to recognize persons of interest from their partial faces. Given a pair of gallery image and probe face patch, we first detect keypoints and extract their local textural features. Then, we propose a robust point set matching method to discriminatively match these two extracted local feature sets, where both the textural information and geometrical information of local features are explicitly used for matching simultaneously. Finally, the similarity of two faces is converted as the distance between these two aligned feature sets. Experimental results on four public face data sets show the effectiveness of the proposed approach.

Label-free biosensing with functionalized nanopipette probes.

PubMed

Umehara, Senkei; Karhanek, Miloslav; Davis, Ronald W; Pourmand, Nader

2009-03-24

Nanopipette technology can uniquely identify biomolecules such as proteins based on differences in size, shape, and electrical charge. These differences are determined by the detection of changes in ionic current as the proteins interact with the nanopipette tip coated with probe molecules. Here we show that electrostatic, biotin-streptavidin, and antibody-antigen interactions on the nanopipette tip surface affect ionic current flowing through a 50-nm pore. Highly charged polymers interacting with the glass surface modulated the rectification property of the nanopipette electrode. Affinity-based binding between the probes tethered to the surface and their target proteins caused a change in the ionic current due to a partial blockade or an altered surface charge. These findings suggest that nanopipettes functionalized with appropriate molecular recognition elements can be used as nanosensors in biomedical and biological research.

Highly selective on-off fluorescence recognition of Fe3+ based on a coumarin derivative and its application in live-cell imaging.

PubMed

Warrier, Sona; Kharkar, Prashant S

2018-01-05

A novel coumarin chemosensor, 7-hydroxy-2-oxo-N-(pyridin-2-ylmethyl)chromene-3-carboxamide (Probe 1), demonstrated significant selectivity towards Fe 3+ ions. Probe 1 exhibited high fluorescence emission profile at 447nm, excellent selectivity towards Fe 3+ over other biologically important metal ions (Al 3+ , Ba 2+ , Co 2+ , Cu 2+ , Zn 2+ , Cd 2+ , Hg 2+ , Pb 2+ and Sn 2+ ). Interestingly, there was ~30-fold decrease in fluorescence intensity upon Fe 3+ binding. The limit of detection of Fe 3+ was found to be 0.76μM (~40ppb). Probe 1 also exhibited high potential as an intracellular chemosensor for Fe 3+ . Copyright © 2017 Elsevier B.V. All rights reserved.

The Brain's Router: A Cortical Network Model of Serial Processing in the Primate Brain

PubMed Central

Zylberberg, Ariel; Fernández Slezak, Diego; Roelfsema, Pieter R.; Dehaene, Stanislas; Sigman, Mariano

2010-01-01

The human brain efficiently solves certain operations such as object recognition and categorization through a massively parallel network of dedicated processors. However, human cognition also relies on the ability to perform an arbitrarily large set of tasks by flexibly recombining different processors into a novel chain. This flexibility comes at the cost of a severe slowing down and a seriality of operations (100–500 ms per step). A limit on parallel processing is demonstrated in experimental setups such as the psychological refractory period (PRP) and the attentional blink (AB) in which the processing of an element either significantly delays (PRP) or impedes conscious access (AB) of a second, rapidly presented element. Here we present a spiking-neuron implementation of a cognitive architecture where a large number of local parallel processors assemble together to produce goal-driven behavior. The precise mapping of incoming sensory stimuli onto motor representations relies on a “router” network capable of flexibly interconnecting processors and rapidly changing its configuration from one task to another. Simulations show that, when presented with dual-task stimuli, the network exhibits parallel processing at peripheral sensory levels, a memory buffer capable of keeping the result of sensory processing on hold, and a slow serial performance at the router stage, resulting in a performance bottleneck. The network captures the detailed dynamics of human behavior during dual-task-performance, including both mean RTs and RT distributions, and establishes concrete predictions on neuronal dynamics during dual-task experiments in humans and non-human primates. PMID:20442869

Large capacity temporary visual memory

PubMed Central

Endress, Ansgar D.; Potter, Mary C.

2014-01-01

Visual working memory (WM) capacity is thought to be limited to three or four items. However, many cognitive activities seem to require larger temporary memory stores. Here, we provide evidence for a temporary memory store with much larger capacity than past WM capacity estimates. Further, based on previous WM research, we show that a single factor — proactive interference — is sufficient to bring capacity estimates down to the range of previous WM capacity estimates. Participants saw a rapid serial visual presentation (RSVP) of 5 to 21 pictures of familiar objects or words presented at rates of 4/s or 8/s, respectively, and thus too fast for strategies such as rehearsal. Recognition memory was tested with a single probe item. When new items were used on all trials, no fixed memory capacities were observed, with estimates of up to 9.1 retained pictures for 21-item lists, and up to 30.0 retained pictures for 100-item lists, and no clear upper bound to how many items could be retained. Further, memory items were not stored in a temporally stable form of memory, but decayed almost completely after a few minutes. In contrast, when, as in most WM experiments, a small set of items was reused across all trials, thus creating proactive interference among items, capacity remained in the range reported in previous WM experiments. These results show that humans have a large-capacity temporary memory store in the absence of proactive interference, and raise the question of whether temporary memory in everyday cognitive processing is severely limited as in WM experiments, or has the much larger capacity found in the present experiments. PMID:23937181

Quantitative detection of Moraxella catarrhalis in nasopharyngeal secretions by real-time PCR.

PubMed

Greiner, Oliver; Day, Philip J R; Altwegg, Martin; Nadal, David

2003-04-01

The recognition of Moraxella catarrhalis as an important cause of respiratory tract infections has been protracted, mainly because it is a frequent commensal organism of the upper respiratory tract and the diagnostic sensitivity of blood or pleural fluid culture is low. Given that the amount of M. catarrhalis bacteria in the upper respiratory tract may change during infection, quantification of these bacteria in nasopharyngeal secretions (NPSs) by real-time PCR may offer a suitable diagnostic approach. Using primers and a fluorescent probe specific for the copB outer membrane protein gene, we detected DNA from serial dilutions of M. catarrhalis cells corresponding to 1 to 10(6) cells. Importantly, there was no difference in the amplification efficiency when the same DNA was mixed with DNA from NPSs devoid of M. catarrhalis. The specificity of the reaction was further confirmed by the lack of amplification of DNAs from other Moraxella species, nontypeable Haemophilus influenzae, H. influenzae type b, Streptococcus pneumoniae, Streptococcus oralis, Streptococcus pyogenes, Bordetella pertussis, Corynebacterium diphtheriae, and various Neisseria species. The assay applied to NPSs from 184 patients with respiratory tract infections performed with a sensitivity of 100% and a specificity of up to 98% compared to the culture results. The numbers of M. catarrhalis organisms detected by real-time PCR correlated with the numbers detected by semiquantitative culture. This real-time PCR assay targeting the copB outer membrane protein gene provided a sensitive and reliable means for the rapid detection and quantification of M. catarrhalis in NPSs; may serve as a tool to study changes in the amounts of M. catarrhalis during lower respiratory tract infections or following vaccination against S. pneumoniae, H. influenzae, or N. meningitidis; and may be applied to other clinical samples.

Quantitative Detection of Moraxella catarrhalis in Nasopharyngeal Secretions by Real-Time PCR

PubMed Central

Greiner, Oliver; Day, Philip J. R.; Altwegg, Martin; Nadal, David

2003-01-01

The recognition of Moraxella catarrhalis as an important cause of respiratory tract infections has been protracted, mainly because it is a frequent commensal organism of the upper respiratory tract and the diagnostic sensitivity of blood or pleural fluid culture is low. Given that the amount of M. catarrhalis bacteria in the upper respiratory tract may change during infection, quantification of these bacteria in nasopharyngeal secretions (NPSs) by real-time PCR may offer a suitable diagnostic approach. Using primers and a fluorescent probe specific for the copB outer membrane protein gene, we detected DNA from serial dilutions of M. catarrhalis cells corresponding to 1 to 106 cells. Importantly, there was no difference in the amplification efficiency when the same DNA was mixed with DNA from NPSs devoid of M. catarrhalis. The specificity of the reaction was further confirmed by the lack of amplification of DNAs from other Moraxella species, nontypeable Haemophilus influenzae, H. influenzae type b, Streptococcus pneumoniae, Streptococcus oralis, Streptococcus pyogenes, Bordetella pertussis, Corynebacterium diphtheriae, and various Neisseria species. The assay applied to NPSs from 184 patients with respiratory tract infections performed with a sensitivity of 100% and a specificity of up to 98% compared to the culture results. The numbers of M. catarrhalis organisms detected by real-time PCR correlated with the numbers detected by semiquantitative culture. This real-time PCR assay targeting the copB outer membrane protein gene provided a sensitive and reliable means for the rapid detection and quantification of M. catarrhalis in NPSs; may serve as a tool to study changes in the amounts of M. catarrhalis during lower respiratory tract infections or following vaccination against S. pneumoniae, H. influenzae, or N. meningitidis; and may be applied to other clinical samples. PMID:12682118

Comparison of 3D cellular imaging techniques based on scanned electron probes: Serial block face SEM vs. Axial bright-field STEM tomography.

PubMed

McBride, E L; Rao, A; Zhang, G; Hoyne, J D; Calco, G N; Kuo, B C; He, Q; Prince, A A; Pokrovskaya, I D; Storrie, B; Sousa, A A; Aronova, M A; Leapman, R D

2018-06-01

Microscopies based on focused electron probes allow the cell biologist to image the 3D ultrastructure of eukaryotic cells and tissues extending over large volumes, thus providing new insight into the relationship between cellular architecture and function of organelles. Here we compare two such techniques: electron tomography in conjunction with axial bright-field scanning transmission electron microscopy (BF-STEM), and serial block face scanning electron microscopy (SBF-SEM). The advantages and limitations of each technique are illustrated by their application to determining the 3D ultrastructure of human blood platelets, by considering specimen geometry, specimen preparation, beam damage and image processing methods. Many features of the complex membranes composing the platelet organelles can be determined from both approaches, although STEM tomography offers a higher ∼3 nm isotropic pixel size, compared with ∼5 nm for SBF-SEM in the plane of the block face and ∼30 nm in the perpendicular direction. In this regard, we demonstrate that STEM tomography is advantageous for visualizing the platelet canalicular system, which consists of an interconnected network of narrow (∼50-100 nm) membranous cisternae. In contrast, SBF-SEM enables visualization of complete platelets, each of which extends ∼2 µm in minimum dimension, whereas BF-STEM tomography can typically only visualize approximately half of the platelet volume due to a rapid non-linear loss of signal in specimens of thickness greater than ∼1.5 µm. We also show that the limitations of each approach can be ameliorated by combining 3D and 2D measurements using a stereological approach. Copyright © 2018. Published by Elsevier Inc.

Dual Mechanism of an Intramolecular Charge Transfer (ICT)-FRET-Based Fluorescent Probe for the Selective Detection of Hydrogen Peroxide.

PubMed

Liang, Xiao; Xu, Xiaoyi; Qiao, Dan; Yin, Zheng; Shang, Luqing

2017-12-14

A dual-mechanism intramolecular charge transfer (ICT)-FRET fluorescent probe for the selective detection of H 2 O 2 in living cells has been designed and synthesized. This probe used a coumarin-naphthalimide hybrid as the FRET platform and a boronate moiety as the recognition group. Upon the addition of H 2 O 2 , the probe exhibited a redshifted (73 nm) fluorescence emission, and the ratio of fluorescence intensities at λ=558 and 485 nm (F 558 /F 485 ) shifted notably (up to 100-fold). Moreover, there was a good linearity (R 2 =0.9911) between the ratio and concentration of H 2 O 2 in the range of 0 to 60 μm, with a limit of detection of 0.28 μm (signal to noise ratio (S/N)=3). This probe could also detect enzymatically generated H 2 O 2 . Importantly, it could be used to visualize endogenous H 2 O 2 produced by stimulation from epidermal growth factor. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Prefrontal Cortex Contributions to Controlled Memory Judgment: fMRI Evidence from Adolescents and Young Adults

ERIC Educational Resources Information Center

Jaeger, Antonio; Selmeczy, Diana; O'Connor, Akira R.; Diaz, Michael; Dobbins, Ian G.

2012-01-01

Cortical regions supporting cognitive control and memory judgment are structurally immature in adolescents. Here we studied adolescents (13-15 y.o.) and young adults (20-22 y.o.) using a recognition memory paradigm that modulates cognitive control demands through cues that probabilistically forecast memory probe status. Behaviorally, adolescence…

The Tentativeness of Scientific Theories: Conceptions of Pre-Service Science Teachers

ERIC Educational Resources Information Center

Jain, Jasmine; Abdullah, Nabilah; Lim, Beh Kian

2014-01-01

The recognition of sound understanding of Nature of Science (NOS) in promoting scientific literacy among individuals has heightened the need to probe NOS conceptions among various groups. However, the nature of quantitative studies in gauging NOS understanding has left the understanding on few NOS aspects insufficiently informed. This paper aimed…

Study of eddy current probes

NASA Technical Reports Server (NTRS)

Workman, Gary L.; Wang, Morgan

1992-01-01

The recognition of materials properties still presents a number of problems for nondestructive testing in aerospace systems. This project attempts to utilize current capabilities in eddy current instrumentation, artificial intelligence, and robotics in order to provide insight into defining geometrical aspects of flaws in composite materials which are capable of being evaluated using eddy current inspection techniques.

Succinic acid functionalized silver nanoparticles (Suc-Ag NPs) for colorimetric sensing of melamine

NASA Astrophysics Data System (ADS)

Rajar, Kausar; Sirajuddin; Balouch, Aamna; Bhanger, M. I.; Shah, Muhammad Tariq; Shaikh, Tayyaba; Siddiqui, Samia

2018-03-01

In this study, a quantitative colorimetric sensing strategy is developed for the rapid, sensitive and selective determination of melamine. The sensing system relies on the application of succinic acid as a selective recognition probe functionalized over Ag NPs. The synthesized Ag NPs were modified with cysteamine to induce positively charged atmosphere which allowed easy and favorable functionalization of succinic acid. The di-carboxyl nature of succinic acid enabled its binding to both cysteamine and melamine. The strong and favorable linkage between succinic acids carbonyl and amine moieties of melamine triggered aggregation of silver NPs producing a significant shift in the measured absorption excitation. This change in the excitation along with the colorimetric response was found linearly proportional to the melamine concentration in the range of 0.1-1.2 μM. The developed sensor system is simple and unlike electrostatic attraction based sensor system utilize selective linkage for the recognition of melamine. In addition to this, the developed optical probe can efficiently be used for the determination of melamine in milk samples.

Non-canonical amino acids bearing thiophene and bithiophene: synthesis by an Ugi multicomponent reaction and studies on ion recognition ability.

PubMed

Esteves, Cátia I C; Raposo, M Manuela M; Costa, Susana P G

2017-05-01

Novel thienyl and bithienyl amino acids with different substituents were obtained by a multicomponent Ugi reaction between a heterocyclic aldehyde, an amine, an acid and an isocyanide. Due to the presence of the sulphur heterocycle at the side chain, these unnatural amino acids are highly emissive and bear extra electron donating atoms so they were tested for their ability to act as fluorescent probes and chemosensors in the recognition of biomedically relevant ions in acetonitrile and acetonitrile/water solutions. The results obtained from spectrophotometric/spectrofluorimetric titrations in the presence of organic and inorganic anions, and alkaline; alkaline-earth and transition metal cations indicated that the bithienyl amino acid bearing a methoxy group is a selective colorimetric chemosensor for Cu 2+ , while the other (bi)thienyl amino acids act as fluorimetric chemosensors with high sensitivity towards Fe 3+ and Cu 2+ in a metal-ligand complex with 1:2 stoichiometry. The photophysical and ion sensing properties of these amino acids confirm their potential as fluorescent probes suitable for incorporation into peptidic frameworks with chemosensory ability.

Effects of joint attention on long-term memory in 9-month-old infants: an event-related potentials study.

PubMed

Kopp, Franziska; Lindenberger, Ulman

2011-07-01

Joint attention develops during the first year of life but little is known about its effects on long-term memory. We investigated whether joint attention modulates long-term memory in 9-month-old infants. Infants were familiarized with visually presented objects in either of two conditions that differed in the degree of joint attention (high versus low). EEG indicators in response to old and novel objects were probed directly after the familiarization phase (immediate recognition), and following a 1-week delay (delayed recognition). In immediate recognition, the amplitude of positive slow-wave activity was modulated by joint attention. In the delayed recognition, the amplitude of the Pb component differentiated between high and low joint attention. In addition, the positive slow-wave amplitude during immediate and delayed recognition correlated with the frequency of infants' looks to the experimenter during familiarization. Under both high- and low-joint-attention conditions, the processing of unfamiliar objects was associated with an enhanced Nc component. Our results show that the degree of joint attention modulates EEG during immediate and delayed recognition. We conclude that joint attention affects long-term memory processing in 9-month-old infants by enhancing the relevance of attended items. © 2010 Blackwell Publishing Ltd.

The structural neuroanatomy of music emotion recognition: Evidence from frontotemporal lobar degeneration

PubMed Central

Omar, Rohani; Henley, Susie M.D.; Bartlett, Jonathan W.; Hailstone, Julia C.; Gordon, Elizabeth; Sauter, Disa A.; Frost, Chris; Scott, Sophie K.; Warren, Jason D.

2011-01-01

Despite growing clinical and neurobiological interest in the brain mechanisms that process emotion in music, these mechanisms remain incompletely understood. Patients with frontotemporal lobar degeneration (FTLD) frequently exhibit clinical syndromes that illustrate the effects of breakdown in emotional and social functioning. Here we investigated the neuroanatomical substrate for recognition of musical emotion in a cohort of 26 patients with FTLD (16 with behavioural variant frontotemporal dementia, bvFTD, 10 with semantic dementia, SemD) using voxel-based morphometry. On neuropsychological evaluation, patients with FTLD showed deficient recognition of canonical emotions (happiness, sadness, anger and fear) from music as well as faces and voices compared with healthy control subjects. Impaired recognition of emotions from music was specifically associated with grey matter loss in a distributed cerebral network including insula, orbitofrontal cortex, anterior cingulate and medial prefrontal cortex, anterior temporal and more posterior temporal and parietal cortices, amygdala and the subcortical mesolimbic system. This network constitutes an essential brain substrate for recognition of musical emotion that overlaps with brain regions previously implicated in coding emotional value, behavioural context, conceptual knowledge and theory of mind. Musical emotion recognition may probe the interface of these processes, delineating a profile of brain damage that is essential for the abstraction of complex social emotions. PMID:21385617

The structural neuroanatomy of music emotion recognition: evidence from frontotemporal lobar degeneration.

PubMed

Omar, Rohani; Henley, Susie M D; Bartlett, Jonathan W; Hailstone, Julia C; Gordon, Elizabeth; Sauter, Disa A; Frost, Chris; Scott, Sophie K; Warren, Jason D

2011-06-01

Despite growing clinical and neurobiological interest in the brain mechanisms that process emotion in music, these mechanisms remain incompletely understood. Patients with frontotemporal lobar degeneration (FTLD) frequently exhibit clinical syndromes that illustrate the effects of breakdown in emotional and social functioning. Here we investigated the neuroanatomical substrate for recognition of musical emotion in a cohort of 26 patients with FTLD (16 with behavioural variant frontotemporal dementia, bvFTD, 10 with semantic dementia, SemD) using voxel-based morphometry. On neuropsychological evaluation, patients with FTLD showed deficient recognition of canonical emotions (happiness, sadness, anger and fear) from music as well as faces and voices compared with healthy control subjects. Impaired recognition of emotions from music was specifically associated with grey matter loss in a distributed cerebral network including insula, orbitofrontal cortex, anterior cingulate and medial prefrontal cortex, anterior temporal and more posterior temporal and parietal cortices, amygdala and the subcortical mesolimbic system. This network constitutes an essential brain substrate for recognition of musical emotion that overlaps with brain regions previously implicated in coding emotional value, behavioural context, conceptual knowledge and theory of mind. Musical emotion recognition may probe the interface of these processes, delineating a profile of brain damage that is essential for the abstraction of complex social emotions. Copyright © 2011 Elsevier Inc. All rights reserved.

Molecular Probing of the HPV-16 E6 Protein Alpha Helix Binding Groove with Small Molecule Inhibitors

PubMed Central

Rietz, Anne; Petrov, Dino P.; Bartolowits, Matthew; DeSmet, Marsha; Davisson, V. Jo; Androphy, Elliot J.

2016-01-01

The human papillomavirus (HPV) HPV E6 protein has emerged as a central oncoprotein in HPV-associated cancers in which sustained expression is required for tumor progression. A majority of the E6 protein interactions within the human proteome use an alpha-helix groove interface for binding. The UBE3A/E6AP HECT domain ubiquitin ligase binds E6 at this helix-groove interface. This enables formation of a trimeric complex with p53, resulting in destruction of this tumor suppressor. While recent x-ray crystal structures are useful, examples of small molecule probes that can modulate protein interactions at this interface are limited. To develop insights useful for potential structure-based design of ligands for HPV E6, a series of 2,6-disubstituted benzopyranones were prepared and tested as competitive antagonists of E6-E6AP helix-groove interactions. These small molecule probes were used in both binding and functional assays to evaluate recognition features of the E6 protein. Evidence for an ionic functional group interaction within the helix groove was implicated by the structure-activity among the highest affinity ligands. The molecular topographies of these protein-ligand interactions were evaluated by comparing the binding and activities of single amino acid E6 mutants with the results of molecular dynamic simulations. A group of arginine residues that form a rim-cap over the E6 helix groove offer compensatory roles in binding and recognition of the small molecule probes. The flexibility and impact on the overall helix-groove shape dictated by these residues offer new insights for structure-based targeting of HPV E6. PMID:26915086

Human Leukocyte Antigen Typing Using a Knowledge Base Coupled with a High-Throughput Oligonucleotide Probe Array Analysis

PubMed Central

Zhang, Guang Lan; Keskin, Derin B.; Lin, Hsin-Nan; Lin, Hong Huang; DeLuca, David S.; Leppanen, Scott; Milford, Edgar L.; Reinherz, Ellis L.; Brusic, Vladimir

2014-01-01

Human leukocyte antigens (HLA) are important biomarkers because multiple diseases, drug toxicity, and vaccine responses reveal strong HLA associations. Current clinical HLA typing is an elimination process requiring serial testing. We present an alternative in situ synthesized DNA-based microarray method that contains hundreds of thousands of probes representing a complete overlapping set covering 1,610 clinically relevant HLA class I alleles accompanied by computational tools for assigning HLA type to 4-digit resolution. Our proof-of-concept experiment included 21 blood samples, 18 cell lines, and multiple controls. The method is accurate, robust, and amenable to automation. Typing errors were restricted to homozygous samples or those with very closely related alleles from the same locus, but readily resolved by targeted DNA sequencing validation of flagged samples. High-throughput HLA typing technologies that are effective, yet inexpensive, can be used to analyze the world’s populations, benefiting both global public health and personalized health care. PMID:25505899

Dielectrophoretic positioning of single nanoparticles on atomic force microscope tips for tip-enhanced Raman spectroscopy.

PubMed

Leiterer, Christian; Deckert-Gaudig, Tanja; Singh, Prabha; Wirth, Janina; Deckert, Volker; Fritzsche, Wolfgang

2015-05-01

Tip-enhanced Raman spectroscopy, a combination of Raman spectroscopy and scanning probe microscopy, is a powerful technique to detect the vibrational fingerprint of molecules at the nanometer scale. A metal nanoparticle at the apex of an atomic force microscope tip leads to a large enhancement of the electromagnetic field when illuminated with an appropriate wavelength, resulting in an increased Raman signal. A controlled positioning of individual nanoparticles at the tip would improve the reproducibility of the probes and is quite demanding due to usually serial and labor-intensive approaches. In contrast to commonly used submicron manipulation techniques, dielectrophoresis allows a parallel and scalable production, and provides a novel approach toward reproducible and at the same time affordable tip-enhanced Raman spectroscopy tips. We demonstrate the successful positioning of an individual plasmonic nanoparticle on a commercial atomic force microscope tip by dielectrophoresis followed by experimental proof of the Raman signal enhancing capabilities of such tips. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sentinel lymph node mapping in melanoma with technetium-99m dextran.

PubMed

Neubauer, S; Mena, I; Iglesis, R; Schwartz, R; Acevedo, J C; Leon, A; Gomez, L

2001-06-01

The aim of this work is to evaluate the capability of Tc99m B Dextran as a lymphoscintigraphic agent in the detection of the sentinel node in skin lesions. Forty-one patients with melanomas (39) and Merkel cell tumors (2) had perilesional intradermal injection of Tc99m-Dextran 2 hours before surgery. Serial gamma camera images and a handheld gamma probe were used to direct sentinel node biopsy. In 39/41 patients, lymph channels and 52 sentinel nodes (one to three sentinel nodes/patient) could be visualized. In one patient, with a dorsal melanoma, no lymph channels or lymph nodes could be demonstrated on the images and only minimal radioactivity was found in the regional nodes with the probe. Another patient with a facial lesion failed to demonstrate lymph channels or nodes. No adverse reactions were observed. Tc99m-Dextran provided good definition of lymph channels and sentinel node localization, without the risks related to the use of potentially hazardous labeled materials of biological origin.

Attentional blink in children with attention deficit hyperactivity disorder.

PubMed

Amador-Campos, Juan A; Aznar-Casanova, J Antonio; Bezerra, Izabela; Torro-Alves, Nelson; Sánchez, Manuel M

2015-01-01

To explore the temporal mechanism of attention in children with attention deficit hyperactivity disorder (ADHD) and controls using a rapid serial visual presentation (RSVP) task in which two letters (T1 and T2) were presented in close temporal proximity among distractors (attentional blink [AB]). Thirty children aged between 9 and 13 years (12 with ADHD combined type and 18 controls) took part in the study. Both groups performed two kinds of RSVP task. In the single task, participants simply had to identify a target letter (T1), whereas in the dual task, they had to identify a target letter (T1) and a probe letter (T2). The ADHD and control groups were equivalent in their single-task performance. However, in the dual-task condition, there were significant between-group differences in the rate of detection of the probe letter (T2) at lag + 1 and lag + 4. The ADHD group exhibited a larger overall AB compared with controls. Our findings provide support for a link between ADHD and attentional blink.

Action Recognition in a Crowded Environment

PubMed Central

Nieuwenhuis, Judith; Bülthoff, Isabelle; Barraclough, Nick; de la Rosa, Stephan

2017-01-01

So far, action recognition has been mainly examined with small point-light human stimuli presented alone within a narrow central area of the observer’s visual field. Yet, we need to recognize the actions of life-size humans viewed alone or surrounded by bystanders, whether they are seen in central or peripheral vision. Here, we examined the mechanisms in central vision and far periphery (40° eccentricity) involved in the recognition of the actions of a life-size actor (target) and their sensitivity to the presence of a crowd surrounding the target. In Experiment 1, we used an action adaptation paradigm to probe whether static or idly moving crowds might interfere with the recognition of a target’s action (hug or clap). We found that this type of crowds whose movements were dissimilar to the target action hardly affected action recognition in central and peripheral vision. In Experiment 2, we examined whether crowd actions that were more similar to the target actions affected action recognition. Indeed, the presence of that crowd diminished adaptation aftereffects in central vision as wells as in the periphery. We replicated Experiment 2 using a recognition task instead of an adaptation paradigm. With this task, we found evidence of decreased action recognition accuracy, but this was significant in peripheral vision only. Our results suggest that the presence of a crowd carrying out actions similar to that of the target affects its recognition. We outline how these results can be understood in terms of high-level crowding effects that operate on action-sensitive perceptual channels. PMID:29308177

Site-specific protein labeling with PRIME and chelation-assisted Click chemistry

PubMed Central

Uttamapinant, Chayasith; Sanchez, Mateo I.; Liu, Daniel S.; Yao, Jennifer Z.; White, Katharine A.; Grecian, Scott; Clarke, Scott; Gee, Kyle R.; Ting, Alice Y.

2016-01-01

This protocol describes an efficient method to site-specifically label cell-surface or purified proteins with chemical probes in two steps: PRobe Incorporation Mediated by Enzymes (PRIME) followed by chelation-assisted copper-catalyzed azide-alkyne cycloaddition (CuAAC). In the PRIME step, Escherichia coli lipoic acid ligase site-specifically attaches a picolyl azide derivative to a 13-amino acid recognition sequence that has been genetically fused onto the protein of interest. Proteins bearing picolyl azide are chemoselectively derivatized with an alkyne-probe conjugate by chelation-assisted CuAAC in the second step. We describe herein the optimized protocols to synthesize picolyl azide, perform PRIME labeling, and achieve CuAAC derivatization of picolyl azide on live cells, fixed cells, and purified proteins. Reagent preparations, including synthesis of picolyl azide probes and expression of lipoic acid ligase, take 12 d, while the procedure to perform site-specific picolyl azide ligation and CuAAC on cells or on purified proteins takes 40 min-3 h. PMID:23887180

Direct Detection of Potential Pyrethroids in Yangtze River via an Imprinted Multilayer Phosphorescence Probe.

PubMed

Chen, Li; Lv, Xiaodong; Dai, Jiangdong; Sun, Lin; Huo, Pengwei; Li, Chunxiang; Yan, Yongsheng

2018-01-01

A novel tailored multilayer probe for monitoring potential pyrethroids in the Yangtze River was proposed. The room-temperature phosphorescence method was applied to realize a detection strategy that is superior to the fluorescence method. Efficient Mn-doped ZnS quantum dots with uniform size of 4.6 nm were firstly coated with a mesoporous silica to obtain a suitable intermediate transition layer, then an imprinted layer containing bifenthrin specific recognition sites was anchored. Characterizations verified the multilayer structure convincingly and the detection process relied on the electron transfer-induced fluorescence quenching mechanism. Optional detection time and standard detection curve were obtained within a concentration range from 5.0 to 50 μmol L -1 . The stability was verified to be good after 12 replicates. Feasibility of the probe was proved by monitoring water samples from the Zhenjiang reach of the Yangtze River. The probe offers promise for direct bifenthrin detection in unknown environmental water with an accurate and stable phosphorescence analysis strategy.

The effect of recognizability on figure-ground processing: does it affect parsing or only figure selection?

PubMed

Navon, David

2011-03-01

Though figure-ground assignment has been shown to be probably affected by recognizability, it appears sensible that object recognition must follow at least the earlier process of figure-ground segregation. To examine whether or not rudimentary object recognition could, counterintuitively, start even before the completion of the stage of parsing in which figure-ground segregation is done, participants were asked to respond, in a go/no-go fashion, whenever any out of 16 alternative connected patterns (that constituted familiar stimuli in the upright orientation) appeared. The white figure of the to-be-attended stimulus-target or foil-could be segregated from the white ambient ground only by means of a frame surrounding it. Such a frame was absent until the onset of target display. Then, to manipulate organizational quality, the greyness of the frame was either gradually increased from zero (in Experiment 1) or changed abruptly to a stationary level whose greyness was varied between trials (in Experiments 2 and 3). Stimulus recognizability was manipulated by orientation angle. In all three experiments the effect of recognizability was found to be considerably larger when organizational quality was minimal due to an extremely faint frame. This result is argued to be incompatible with any version of a serial thesis suggesting that processing aimed at object recognition starts only with a good enough level of organizational quality. The experiments rather provide some support to the claim, termed here "early interaction hypothesis", positing interaction between early recognition processing and preassignment parsing processes.

Oxytocin enhances attentional bias for neutral and positive expression faces in individuals with higher autistic traits.

PubMed

Xu, Lei; Ma, Xiaole; Zhao, Weihua; Luo, Lizhu; Yao, Shuxia; Kendrick, Keith M

2015-12-01

There is considerable interest in the potential therapeutic role of the neuropeptide oxytocin in altering attentional bias towards emotional social stimuli in psychiatric disorders. However, it is still unclear whether oxytocin primarily influences attention towards positive or negative valence social stimuli. Here in a double-blind, placebo controlled, between subject design experiment in 60 healthy male subjects we have used the highly sensitive dual-target rapid serial visual presentation (RSVP) paradigm to investigate whether intranasal oxytocin (40IU) treatment alters attentional bias for emotional faces. Results show that oxytocin improved recognition accuracy of neutral and happy expression faces presented in the second target position (T2) during the period of reduced attentional capacity following prior presentation of a first neutral face target (T1), but had no effect on recognition of negative expression faces (angry, fearful, sad). Oxytocin also had no effect on recognition of non-social stimuli (digits) in this task. Recognition accuracy for neutral faces at T2 was negatively associated with autism spectrum quotient (ASQ) scores in the placebo group, and oxytocin's facilitatory effects were restricted to a sub-group of subjects with higher ASQ scores. Our results therefore indicate that oxytocin primarily enhances the allocation of attentional resources towards faces expressing neutral or positive emotion and does not influence that towards negative emotion ones or non-social stimuli. This effect of oxytocin is strongest in healthy individuals with higher autistic trait scores, thereby providing further support for its potential therapeutic use in autism spectrum disorder. Copyright © 2015 Elsevier Ltd. All rights reserved.

Self-Assembled Core-Satellite Gold Nanoparticle Networks for Ultrasensitive Detection of Chiral Molecules by Recognition Tunneling Current.

PubMed

Zhang, Yuanchao; Liu, Jingquan; Li, Da; Dai, Xing; Yan, Fuhua; Conlan, Xavier A; Zhou, Ruhong; Barrow, Colin J; He, Jin; Wang, Xin; Yang, Wenrong

2016-05-24

Chirality sensing is a very challenging task. Here, we report a method for ultrasensitive detection of chiral molecule l/d-carnitine based on changes in the recognition tunneling current across self-assembled core-satellite gold nanoparticle (GNP) networks. The recognition tunneling technique has been demonstrated to work at the single molecule level where the binding between the reader molecules and the analytes in a nanojunction. This process was observed to generate a unique and sensitive change in tunneling current, which can be used to identify the analytes of interest. The molecular recognition mechanism between amino acid l-cysteine and l/d-carnitine has been studied with the aid of SERS. The different binding strength between homo- or heterochiral pairs can be effectively probed by the copper ion replacement fracture. The device resistance was measured before and after the sequential exposures to l/d-carnitine and copper ions. The normalized resistance change was found to be extremely sensitive to the chirality of carnitine molecule. The results suggested that a GNP networks device optimized for recognition tunneling was successfully built and that such a device can be used for ultrasensitive detection of chiral molecules.

Recognition Memory for Realistic Synthetic Faces

PubMed Central

Yotsumoto, Yuko; Kahana, Michael J.; Wilson, Hugh R.; Sekuler, Robert

2006-01-01

A series of experiments examined short-term recognition memory for trios of briefly-presented, synthetic human faces derived from three real human faces. The stimuli were graded series of faces, which differed by varying known amounts from the face of the average female. Faces based on each of the three real faces were transformed so as to lie along orthogonal axes in a 3-D face space. Experiment 1 showed that the synthetic faces' perceptual similarity stucture strongly influenced recognition memory. Results were fit by NEMo, a noisy exemplar model of perceptual recognition memory. The fits revealed that recognition memory was influenced both by the similarity of the probe to series items, and by the similarities among the series items themselves. Non-metric multi-dimensional scaling (MDS) showed that faces' perceptual representations largely preserved the 3-D space in which the face stimuli were arrayed. NEMo gave a better account of the results when similarity was defined as perceptual, MDS similarity rather than physical proximity of one face to another. Experiment 2 confirmed the importance of within-list homogeneity directly, without mediation of a model. We discuss the affinities and differences between visual memory for synthetic faces and memory for simpler stimuli. PMID:17948069

Development of novel small molecules for imaging and drug release

NASA Astrophysics Data System (ADS)

Cao, Yanting

Small organic molecules, including small molecule based fluorescent probes, small molecule based drugs or prodrugs, and smart multifunctional fluorescent drug delivery systems play important roles in biological research, drug discovery, and clinical practices. Despite the significant progress made in these fields, the development of novel and diverse small molecules is needed to meet various demands for research and clinical applications. My Ph.D study focuses on the development of novel functional molecules for recognition, imaging and drug release. In the first part, a turn-on fluorescent probe is developed for the detection of intracellular adenosine-5'-triphosphate (ATP) levels based on multiplexing recognitions. Considering the unique and complicated structure of ATP molecules, a fluorescent probe has been implemented with improved sensitivity and selectivity due to two synergistic binding recognitions by incorporating of 2, 2'-dipicolylamine (Dpa)-Zn(II) for targeting of phospho anions and phenylboronic acid group for cis-diol moiety. The novel probe is able to detect intracellular ATP levels in SH-SY5Y cells. Meanwhile, the advantages of multiplexing recognition design concept have been demonstrated using two control molecules. In the second part, a prodrug system is developed to deliver multiple drugs within one small molecule entity. The prodrug is designed by using 1-(2-nitrophenyl)ethyl (NPE) as phototrigger, and biphenol biquaternary ammonium as the prodrug. With controlled photo activation, both DNA cross-linking agents mechlorethamine and o-quinone methide are delivered and released at the preferred site, leading to efficient DNA cross-links formation and cell death. The prodrug shows negligible cytotoxicity towards normal skin cells (Hekn cells) with and without UV activation, but displays potent activity towards cancer cells (HeLa cells) upon UV activation. The multiple drug release system may hold a great potential for practical application. In the last part, a new photo-initiated fluorescent anticancer prodrug for DNA alkylating agent mechlorethamine releasing and monitoring has been developed. The theranostic prodrug consists a photolabile NPE group, an inactive form of mechlorethamine and a nonfluorescent coumarin in one small molecule. It is demonstrated that the prodrug shows negligible cytotoxicity towards normal skin cells (Hekn cells) with and without UV activation, while the original parent drug mechlorethamine can be photocontrol-released and induces effective DNA cross-linking activity. Importantly, the drug release progress can be conveniently monitored by the 'off-on' fluorescence enhancement in cells. Moreover, the selective prodrug is not only cell permeable but also nuclear permeable. Therefore, the prodrug serves as a promising drug delivery system for spatiotemporal control release and monitoring of an anticancer drug to obtain the optimal treatment efficacy.

Masking effects of speech and music: does the masker's hierarchical structure matter?

PubMed

Shi, Lu-Feng; Law, Yvonne

2010-04-01

Speech and music are time-varying signals organized by parallel hierarchical rules. Through a series of four experiments, this study compared the masking effects of single-talker speech and instrumental music on speech perception while manipulating the complexity of hierarchical and temporal structures of the maskers. Listeners' word recognition was found to be similar between hierarchically intact and disrupted speech or classical music maskers (Experiment 1). When sentences served as the signal, significantly greater masking effects were observed with disrupted than intact speech or classical music maskers (Experiment 2), although not with jazz or serial music maskers, which differed from the classical music masker in their hierarchical structures (Experiment 3). Removing the classical music masker's temporal dynamics or partially restoring it affected listeners' sentence recognition; yet, differences in performance between intact and disrupted maskers remained robust (Experiment 4). Hence, the effect of structural expectancy was largely present across maskers when comparing them before and after their hierarchical structure was purposefully disrupted. This effect seemed to lend support to the auditory stream segregation theory.

Label-free biosensing with functionalized nanopipette probes

PubMed Central

Umehara, Senkei; Karhanek, Miloslav; Davis, Ronald W.; Pourmand, Nader

2009-01-01

Nanopipette technology can uniquely identify biomolecules such as proteins based on differences in size, shape, and electrical charge. These differences are determined by the detection of changes in ionic current as the proteins interact with the nanopipette tip coated with probe molecules. Here we show that electrostatic, biotin-streptavidin, and antibody-antigen interactions on the nanopipette tip surface affect ionic current flowing through a 50-nm pore. Highly charged polymers interacting with the glass surface modulated the rectification property of the nanopipette electrode. Affinity-based binding between the probes tethered to the surface and their target proteins caused a change in the ionic current due to a partial blockade or an altered surface charge. These findings suggest that nanopipettes functionalized with appropriate molecular recognition elements can be used as nanosensors in biomedical and biological research. PMID:19264962

Small Molecule Chemical Probes of MicroRNA Function

PubMed Central

Velagapudi, Sai Pradeep; Vummidi, Balayeshwanth R.; Disney, Matthew D.

2015-01-01

MicroRNAs (miRNAs) are small, non-coding RNAs that control protein expression. Aberrant miRNA expression has been linked to various human diseases, and thus miRNAs have been explored as diagnostic markers and therapeutic targets. Although it is challenging to target RNA with small molecules in general, there have been successful campaigns that have identified small molecule modulators of miRNA function by targeting various pathways. For example, small molecules that modulate transcription and target nuclease processing sites in miRNA precursors have been identified. Herein, we describe challenges in developing chemical probes that target miRNAs and highlight aspects of miRNA cellular biology elucidated by using small molecule chemical probes. We expect that this area will expand dramatically in the near future as strides are made to understand small molecule recognition of RNA from a fundamental perspective. PMID:25500006

The effect of word length in short-term memory: Is rehearsal necessary?

PubMed

Campoy, Guillermo

2008-05-01

Three experiments investigated the effect of word length on a serial recognition task when rehearsal was prevented by a high presentation rate with no delay between study and test lists. Results showed that lists of short four-phoneme words were better recognized than lists of long six-phoneme words. Moreover, this effect was equivalent to that observed in conditions in which there was a delay between lists, thereby making rehearsal possible in the interval. These findings imply that rehearsal does not play a central role in the origin of the word length effect. An alternative explanation based on differences in the degree of retroactive interference generated by long and short words is proposed.

Biomolecule recognition using piezoresistive nanomechanical force probes

NASA Astrophysics Data System (ADS)

Tosolini, Giordano; Scarponi, Filippo; Cannistraro, Salvatore; Bausells, Joan

2013-06-01

Highly sensitive sensors are one of the enabling technologies for the biomarker detection in early stage diagnosis of pathologies. We have developed a self-sensing nanomechanical force probe able for detecting the unbinding of single couples of biomolecular partners in nearly physiological conditions. The embedding of a piezoresistive transducer into a nanomechanical cantilever enabled high force measurement capability with sub 10-pN resolution. Here, we present the design, microfabrication, optimization, and complete characterization of the sensor. The exceptional electromechanical performance obtained allowed us to detect biorecognition specific events underlying the biotin-avidin complex formation, by integrating the sensor in a commercial atomic force microscope.

Colorimetric and fluorescent detection of hydrazine with high sensitivity and excellent selectivity

NASA Astrophysics Data System (ADS)

Shi, Bingjie; Qi, Sujie; Yu, Mingming; Liu, Chunxia; Li, Zhanxian; Wei, Liuhe; Ni, Zhonghai

2018-01-01

It is critical to develop probes for rapid, selective, and sensitive detection of the highly toxic hydrazine in both environmental and biological science. In this work, under mild condition, a novel colorimetric and off-on fluorescent probe was synthesized for rapid recognition of hydrazine with excellent selectivity over other various species including some biological species, metal ions and anions. The limit of quantification (LOQ) value was 1.5 × 10- 4 M-3.2 × 10- 3 M (colorimetric method) and 1.5 × 10- 4 M - 3.2 × 10- 3 M (fluorescent method) with as low as detection limit of 46.2 μM.

Fluorenone based fluorescent probe for selective "turn-on" detection of pyrophosphate and alanine

NASA Astrophysics Data System (ADS)

Daniel Thangadurai, T.; Nithya, I.; Manjubaashini, N.; Bhuvanesh, N.; Bharathi, G.; Nandhakumar, R.; Nataraj, D.

2018-06-01

To sense biologically important entities with different size and dimensions, a fluorenone based fluorescent receptor was designed and synthesized. Probe 1 displayed a distinct fluorescence enhancement emission at 565 nm for pyrophosphate and 530 nm for alanine in polar solvent. The fluorescence titration experiments confirm 1:1 stoichiometric ratio with high-binding constant and very low limit of detection (LoD) values. Receptor 1 showed a highly selective and sensitive recognition to HP2O73 - and to alanine over other competitive anions and amino acids. In addition, the fluorescence lifetime measurement and reversible binding study results support the practical importance of 1.

Recent Progress in Aptamer-Based Functional Probes for Bioanalysis and Biomedicine.

PubMed

Zhang, Huimin; Zhou, Leiji; Zhu, Zhi; Yang, Chaoyong

2016-07-11

Nucleic acid aptamers are short synthetic DNA or RNA sequences that can bind to a wide range of targets with high affinity and specificity. In recent years, aptamers have attracted increasing research interest due to their unique features of high binding affinity and specificity, small size, excellent chemical stability, easy chemical synthesis, facile modification, and minimal immunogenicity. These properties make aptamers ideal recognition ligands for bioanalysis, disease diagnosis, and cancer therapy. This review highlights the recent progress in aptamer selection and the latest applications of aptamer-based functional probes in the fields of bioanalysis and biomedicine. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Simple Bioconjugate Attachment Protocol for Use in Single Molecule Force Spectroscopy Experiments Based on Mixed Self-Assembled Monolayers

PubMed Central

Attwood, Simon J.; Simpson, Anna M. C.; Stone, Rachael; Hamaia, SamirW.; Roy, Debdulal; Farndale, RichardW.; Ouberai, Myriam; Welland, Mark E.

2012-01-01

Single molecule force spectroscopy is a technique that can be used to probe the interaction force between individual biomolecular species. We focus our attention on the tip and sample coupling chemistry, which is crucial to these experiments. We utilised a novel approach of mixed self-assembled monolayers of alkanethiols in conjunction with a heterobifunctional crosslinker. The effectiveness of the protocol is demonstrated by probing the biotin-avidin interaction. We measured unbinding forces comparable to previously reported values measured at similar loading rates. Specificity tests also demonstrated a significant decrease in recognition after blocking with free avidin. PMID:23202965

Adaptive changes in the neuromagnetic response of the primary and association somatosensory areas following repetitive tactile hand stimulation in humans

PubMed Central

Popescu, Anda; Barlow, Steven; Venkatesan, Lalit; Wang, Jingyan; Popescu, Mihai

2014-01-01

Cortical adaptation in the primary somatosensory cortex (SI) has been probed using different stimulation modalities and recording techniques, in both human and animal studies. In contrast, considerably less knowledge has been gained about the adaptation profiles in other areas of the cortical somatosensory network. Using magnetoencephalography, we examined the patterns of short-term adaptation for evoked responses in SI and somatosensory association areas during tactile stimulation applied to the glabrous skin of the right hand. Cutaneous stimuli were delivered as trains of serial pulses with a constant frequency of 2 Hz and 4 Hz in separate runs, and a constant inter-train interval of 5 s. The unilateral stimuli elicited transient responses to the serial pulses in the train, with several response components that were separated by Independent Component Analysis. Subsequent neuromagnetic source reconstruction identified regional generators in the contralateral SI and somatosensory association areas in the posterior parietal cortex (PPC). Activity in the bilateral secondary somatosensory cortex (i.e. SII/PV) was also identified, although less consistently across subjects. The dynamics of the evoked activity in each area and the frequency-dependent adaptation effects were assessed from the changes in the relative amplitude of serial responses in each train. We show that the adaptation profiles in SI and PPC can be quantitatively characterized from neuromagnetic recordings using tactile stimulation, with the sensitivity to repetitive stimulation increasing from SI to PPC. A similar approach for SII/PV has proven less straightforward, potentially due to the selective nature of these areas to respond predominantly to certain stimuli. PMID:22331631

A 2D range Hausdorff approach to 3D facial recognition.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koch, Mark William; Russ, Trina Denise; Little, Charles Quentin

2004-11-01

This paper presents a 3D facial recognition algorithm based on the Hausdorff distance metric. The standard 3D formulation of the Hausdorff matching algorithm has been modified to operate on a 2D range image, enabling a reduction in computation from O(N2) to O(N) without large storage requirements. The Hausdorff distance is known for its robustness to data outliers and inconsistent data between two data sets, making it a suitable choice for dealing with the inherent problems in many 3D datasets due to sensor noise and object self-occlusion. For optimal performance, the algorithm assumes a good initial alignment between probe and templatemore » datasets. However, to minimize the error between two faces, the alignment can be iteratively refined. Results from the algorithm are presented using 3D face images from the Face Recognition Grand Challenge database version 1.0.« less

Strength-based criterion shifts in recognition memory.

PubMed

Singer, Murray

2009-10-01

In manipulations of stimulus strength between lists, a more lenient signal detection criterion is more frequently applied to a weak than to a strong stimulus class. However, with randomly intermixed weak and strong test probes, such a criterion shift often does not result. A procedure that has yielded delay-based within-list criterion shifts was applied to strength manipulations in recognition memory for categorized word lists. When participants made semantic ratings about each stimulus word, strength-based criterion shifts emerged regardless of whether words from pairs of categories were studied in separate blocks (Experiment 1) or in intermixed blocks (Experiment 2). In Experiment 3, the criterion shift persisted under the semantic-rating study task, but not under rote memorization. These findings suggest that continually adjusting the recognition decision criterion is cognitively feasible. They provide a technique for manipulating the criterion shift, and they identify competing theoretical accounts of these effects.

Robust selectivity to two-object images in human visual cortex

PubMed Central

Agam, Yigal; Liu, Hesheng; Papanastassiou, Alexander; Buia, Calin; Golby, Alexandra J.; Madsen, Joseph R.; Kreiman, Gabriel

2010-01-01

SUMMARY We can recognize objects in a fraction of a second in spite of the presence of other objects [1–3]. The responses in macaque areas V4 and inferior temporal cortex [4–15] to a neuron’s preferred stimuli are typically suppressed by the addition of a second object within the receptive field (see however [16, 17]). How can this suppression be reconciled with rapid visual recognition in complex scenes? One option is that certain “special categories” are unaffected by other objects [18] but this leaves the problem unsolved for other categories. Another possibility is that serial attentional shifts help ameliorate the problem of distractor objects [19–21]. Yet, psychophysical studies [1–3], scalp recordings [1] and neurophysiological recordings [14, 16, 22–24], suggest that the initial sweep of visual processing contains a significant amount of information. We recorded intracranial field potentials in human visual cortex during presentation of flashes of two-object images. Visual selectivity from temporal cortex during the initial ~200 ms was largely robust to the presence of other objects. We could train linear decoders on the responses to isolated objects and decode information in two-object images. These observations are compatible with parallel, hierarchical and feed-forward theories of rapid visual recognition [25] and may provide a neural substrate to begin to unravel rapid recognition in natural scenes. PMID:20417105

Face Recognition via Ensemble SIFT Matching of Uncorrelated Hyperspectral Bands and Spectral PCTs

DTIC Science & Technology

2011-06-01

Operational Sciences Graduate School of Engineering and Management Air Force Institute of Technology Air University Air...Education and Training Command In Partial Fulfillment of the Requirements for the Degree of Master of Science in Operations Research...Comparison of performance against different categories of probes (Phillips, Moon, Rauss, & Rizvi, 1997, p. 141

Logical Metonymy Resolution in a Words-as-Cues Framework: Evidence from Self-Paced Reading and Probe Recognition

ERIC Educational Resources Information Center

Zarcone, Alessandra; Padó, Sebastian; Lenci, Alessandro

2014-01-01

Logical metonymy resolution ("begin a book" ? "begin reading a book" or "begin writing a book") has traditionally been explained either through complex lexical entries (qualia structures) or through the integration of the implicit event via post-lexical access to world knowledge. We propose that recent work within the…

Sentence and Discourse Processes in Skilled Comprehension. Resource Publication Series 4 No. 3.

ERIC Educational Resources Information Center

Townsend, David J.

This research disproves the hypothesis that less-skilled comprehenders are less able to take advantage of constraints at all levels of structure. Five studies used self-paced reading, meaning probe judgment, recall, and sentence and word recognition tasks to examine the effect of supportive discourse contexts on sentence processing in skilled and…

Fluorescent sensor based models for the detection of environmentally-related toxic heavy metals.

PubMed

Rasheed, Tahir; Bilal, Muhammad; Nabeel, Faran; Iqbal, Hafiz M N; Li, Chuanlong; Zhou, Yongfeng

2018-02-15

The quest for industrial and biotechnological revolution has been contributed in increasing environmental contamination issues, worldwide. The controlled or uncontrolled release of hazardous pollutants from various industrial sectors is one of the key problems facing humanity. Among them, adverse influences of lead, cadmium, and mercury on human health are well known to cause many disorders like reproductive, neurological, endocrine system, and cardiovascular, etc. Besides their presence at lower concentrations, most of these toxic heavy metals are posing noteworthy toxicological concerns. In this context, notable efforts from various regulatory authorities, the increase in the concentration of these toxic heavy metals in the environment is of serious concern, so real-time monitoring is urgently required. This necessitates the exploration for novel and efficient probes for recognition of these toxic agents. Among various methodologies adopted for tailoring such probes, generally the methodologies, in which changes associated with spectral properties, are preferred for the deceptive ease in the recognition process. Accordingly, a promising modality has emerged in the form of radiometric and colorimetric monitoring of these toxic agents. Herein, we review fluorescent sensor based models and their potentialities to address the detection fate of hazardous pollutants for a cleaner environment. Second, recent advances regarding small molecule and rhodamine-based fluorescent sensors, radiometric and colorimetric probes are discussed. The information is also given on the photoinduced electron transfer (PET) mechanism, chelation enhancement fluorescence (CHEF) effect and spirocyclic ring opening mechanism. Copyright © 2017 Elsevier B.V. All rights reserved.

Is attentional prioritisation of infant faces unique in humans?: Comparative demonstrations by modified dot-probe task in monkeys.

PubMed

Koda, Hiroki; Sato, Anna; Kato, Akemi

2013-09-01

Humans innately perceive infantile features as cute. The ethologist Konrad Lorenz proposed that the infantile features of mammals and birds, known as the baby schema (kindchenschema), motivate caretaking behaviour. As biologically relevant stimuli, newborns are likely to be processed specially in terms of visual attention, perception, and cognition. Recent demonstrations on human participants have shown visual attentional prioritisation to newborn faces (i.e., newborn faces capture visual attention). Although characteristics equivalent to those found in the faces of human infants are found in nonhuman primates, attentional capture by newborn faces has not been tested in nonhuman primates. We examined whether conspecific newborn faces captured the visual attention of two Japanese monkeys using a target-detection task based on dot-probe tasks commonly used in human visual attention studies. Although visual cues enhanced target detection in subject monkeys, our results, unlike those for humans, showed no evidence of an attentional prioritisation for newborn faces by monkeys. Our demonstrations showed the validity of dot-probe task for visual attention studies in monkeys and propose a novel approach to bridge the gap between human and nonhuman primate social cognition research. This suggests that attentional capture by newborn faces is not common to macaques, but it is unclear if nursing experiences influence their perception and recognition of infantile appraisal stimuli. We need additional comparative studies to reveal the evolutionary origins of baby-schema perception and recognition. Copyright © 2013 Elsevier B.V. All rights reserved.

Clinical evaluation of P-glycoprotein inhibition by venetoclax: a drug interaction study with digoxin.

PubMed

Chiney, Manoj S; Menon, Rajeev M; Bueno, Orlando F; Tong, Bo; Salem, Ahmed Hamed

2018-09-01

1. Venetoclax is a novel, small molecule B-cell lymphoma-2 (BCL-2) inhibitor that has demonstrated clinical efficacy in a variety of haematological malignancies. Since venetoclax is an inhibitor of P glycoprotein (P-gp) transporter, a study was conducted in healthy, female volunteers to evaluate the effect of venetoclax on the pharmacokinetics of digoxin, a P-gp probe substrate. 2. Volunteers received a single oral dose of digoxin (0.5 mg) with or without a single oral dose of venetoclax (100  mg). Serial blood samples were obtained for pharmacokinetic assessments of digoxin and venetoclax and serial urine samples were obtained for measurement of digoxin concentrations. Safety was assessed throughout the study. 3. Coadministration of digoxin and venetoclax increased digoxin maximum observed plasma concentration (C max ) by 35% and area under the plasma-concentration time curve (AUC 0-∞) by 9%. Digoxin half-life, renal clearance and the fraction excreted unchanged in urine remained relatively similar. The results of this study indicate that venetoclax can increase the concentrations of P-gp substrates. Narrow therapeutic index P-gp substrates should be administered six hours prior to venetoclax to minimise the potential interaction.

Study of carbon nanotube-rich impedimetric recognition electrode for ultra-low determination of polycyclic aromatic hydrocarbons in water.

PubMed

Muñoz, Jose; Navarro-Senent, Cristina; Crivillers, Nuria; Mas-Torrent, Marta

2018-04-14

Carbon nanotubes (CNTs) have been studied as an electrochemical recognition element for the impedimetric determination of priority polycyclic aromatic hydrocarbons (PAHs) in water, using hexocyanoferrate as a redox probe. For this goal, an indium tin oxide (ITO) electrode functionalized with a silane-based self-assembled monolayer carrying CNTs has been engineered. The electroanalytical method, which is similar to an antibody-antigen assay, is straightforward and exploits the high CNT-PAH affinity obtained via π-interactions. After optimizing the experimental conditions, the resulting CNT-based impedimetric recognition platform exhibits ultra-low detection limits (1.75 ± 0.04 ng·L -1 ) for the sum of PAHs tested, which was also validated by using a certified reference PAH mixture. Graphical abstract Schematic of an indium-tin-oxide (ITO) electrode functionalized with a silane-based self-assembled monolayer carrying carbon nanotubes (CNTs) as a recognition platform for the ultra-low determination of total polycyclic aromatic hydrocarbons (PAHs) in water via π-interactions using Electrochemical Impedance Spectroscopy (EIS).

Selective and Sensitive Detection of Cyanide Based on the Displacement Strategy Using a Water-Soluble Fluorescent Probe.

PubMed

La, Ming; Hao, Yuanqiang; Wang, Zhaoyang; Han, Guo-Cheng; Qu, Lingbo

2016-01-01

A water-soluble fluorescent probe (C-GGH) was used for the highly sensitive and selective detection of cyanide (CN(-)) in aqueous media based on the displacement strategy. Due to the presence of the recognition unit GGH (Gly-Gly-His), the probe C-GGH can coordinate with Cu(2+) and consequently display ON-OFF type fluorescence response. Furthermore, the in situ formed nonfluorescent C-GGH-Cu(2+) complex can act as an effective OFF-ON type fluorescent probe for sensing CN(-) anion. Due to the strong binding affinity of CN(-) to Cu(2+), CN(-) can extract Cu(2+) from C-GGH-Cu(2+) complex, leading to the release of C-GGH and the recovery of fluorescent emission of the system. The probe C-GGH-Cu(2+) allowed detection of CN(-) in aqueous solution with a LOD (limit of detection) of 0.017 μmol/L which is much lower than the maximum contaminant level (1.9 μmol/L) for CN(-) in drinking water set by the WHO (World Health Organization). The probe also displayed excellent specificity for CN(-) towards other anions, including F(-), Cl(-), Br(-), I(-), SCN(-), PO4 (3-), N3 (-), NO3 (-), AcO(-), SO4 (2-), and CO3 (2-).

Selective and Sensitive Detection of Cyanide Based on the Displacement Strategy Using a Water-Soluble Fluorescent Probe

PubMed Central

La, Ming; Hao, Yuanqiang; Wang, Zhaoyang; Han, Guo-Cheng; Qu, Lingbo

2016-01-01

A water-soluble fluorescent probe (C-GGH) was used for the highly sensitive and selective detection of cyanide (CN−) in aqueous media based on the displacement strategy. Due to the presence of the recognition unit GGH (Gly-Gly-His), the probe C-GGH can coordinate with Cu2+ and consequently display ON-OFF type fluorescence response. Furthermore, the in situ formed nonfluorescent C-GGH-Cu2+ complex can act as an effective OFF-ON type fluorescent probe for sensing CN− anion. Due to the strong binding affinity of CN− to Cu2+, CN− can extract Cu2+ from C-GGH-Cu2+ complex, leading to the release of C-GGH and the recovery of fluorescent emission of the system. The probe C-GGH-Cu2+ allowed detection of CN− in aqueous solution with a LOD (limit of detection) of 0.017 μmol/L which is much lower than the maximum contaminant level (1.9 μmol/L) for CN− in drinking water set by the WHO (World Health Organization). The probe also displayed excellent specificity for CN− towards other anions, including F−, Cl−, Br−, I−, SCN−, PO4 3−, N3 −, NO3 −, AcO−, SO4 2−, and CO3 2−. PMID:26881185

DNA microdevice for electrochemical detection of Escherichia coli 0157:H7 molecular markers.

PubMed

Berganza, J; Olabarria, G; García, R; Verdoy, D; Rebollo, A; Arana, S

2007-04-15

An electrochemical DNA sensor based on the hybridization recognition of a single-stranded DNA (ssDNA) probe immobilized onto a gold electrode to its complementary ssDNA is presented. The DNA probe is bound on gold surface electrode by using self-assembled monolayer (SAM) technology. An optimized mixed SAM with a blocking molecule preventing the nonspecific adsorption on the electrode surface has been prepared. In this paper, a DNA biosensor is designed by means of the immobilization of a single stranded DNA probe on an electrochemical transducer surface to recognize specifically Escherichia coli (E. coli) 0157:H7 complementary target DNA sequence via cyclic voltammetry experiments. The 21 mer DNA probe including a C6 alkanethiol group at the 5' phosphate end has been synthesized to form the SAM onto the gold surface through the gold sulfur bond. The goal of this paper has been to design, characterise and optimise an electrochemical DNA sensor. In order to investigate the oligonucleotide probe immobilization and the hybridization detection, experiments with different concentration of DNA and mismatch sequences have been performed. This microdevice has demonstrated the suitability of oligonucleotide Self-assembled monolayers (SAMs) on gold as immobilization method. The DNA probes deposited on gold surface have been functional and able to detect changes in bases sequence in a 21-mer oligonucleotide.

Specificity tests of an oligonucleotide probe against food-outbreak salmonella for biosensor detection

NASA Astrophysics Data System (ADS)

Chen, I.-H.; Horikawa, S.; Xi, J.; Wikle, H. C.; Barbaree, J. M.; Chin, B. A.

2017-05-01

Phage based magneto-elastic (ME) biosensors have been shown to be able to rapidly detect Salmonella in various food systems to serve food pathogen monitoring purposes. In this ME biosensor platform, the free-standing strip-shaped magneto-elastic sensor is the transducer and the phage probe that recognizes Salmonella in food serves as the bio-recognition element. According to Sorokulova et al. at 2005, a developed oligonucleotide probe E2 was reported to have high specificity to Salmonella enterica Typhimurium. In the report, the specificity tests were focused in most of Enterobacterace groups outside of Salmonella family. Here, to understand the specificity of phage E2 to different Salmonella enterica serotypes within Salmonella Family, we further tested the specificity of the phage probe to thirty-two Salmonella serotypes that were present in the major foodborne outbreaks during the past ten years (according to Centers for Disease Control and Prevention). The tests were conducted through an Enzyme linked Immunosorbent Assay (ELISA) format. This assay can mimic probe immobilized conditions on the magnetoelastic biosensor platform and also enable to study the binding specificity of oligonucleotide probes toward different Salmonella while avoiding phage/ sensor lot variations. Test results confirmed that this oligonucleotide probe E2 was high specific to Salmonella Typhimurium cells but showed cross reactivity to Salmonella Tennessee and four other serotypes among the thirty-two tested Salmonella serotypes.

A multifunctional probe based on the use of labeled aptamer and magnetic nanoparticles for fluorometric determination of adenosine 5'-triphosphate.

PubMed

Liu, Xiaojie; Lin, Bixia; Yu, Ying; Cao, Yujuan; Guo, Manli

2018-04-02

A multifunctional fluorescent probe is synthesized for the determination of adenosine 5'-triphosphate (ATP). The 6-carboxyfluorescein-labeled aptamer (FAM-aptamer) was bound to the surface of magnetite nanoparticles coated with polydopamine (Fe 3 O 4 @PDA) by π-π stacking interaction to form the multifunctional probe. The probe has three functions including recognition, magnetic separation, and yielding a fluorescent signal. In the presence of ATP, FAM-aptamer on the surface of the probe binds to ATP and returns to the solution. Thus, the fluorescence of the supernatant is enhanced and can be related to the concentration of ATP. Fluorescence intensities were measured at excitation/emission wavelengths of 494/526 nm. Response is linear in the 0.1-100 μM ATP concentration range, and the detection limit is 89 nM. The probe was applied to the quantitation of ATP in spiked human urine and serum samples, with recoveries ranging between 94.8 and 102%. Graphical abstract A multifunctional fluorescent probe based on the use of FAM-aptamer and Fe 3 O 4 @PDA is described for the determination of ATP in spiked human urine and serum samples. FAM-aptamer: 6-carboxyfluorescein-labeled aptamer; Fe 3 O 4 @PDA: magnetite nanoparticles coated with polydopamine. ATP: adenosine 5'-triphosphate.

A Pilot Study Examining a Computer-Based Intervention to Improve Recognition and Understanding of Emotions in Young Children with Communication and Social Deficits.

PubMed

Romero, Neri L

2017-06-01

A common social impairment in individuals with ASD is difficulty interpreting and or predicting emotions of others. To date, several interventions targeting teaching emotion recognition and understanding have been utilized both by researchers and practitioners. The results suggest that teaching emotion recognition is possible, but that the results do not generalize to non-instructional contexts. This study sought to replicate earlier findings of a positive impact of teaching emotion recognition using a computer-based intervention and to extend it by testing for generalization on live models in the classroom setting. Two boys and one girl, four to eight years in age, educated in self-contained classrooms for students with communication and social skills deficits, participated in this study. A multiple probe across participants design was utilized. Measures of emotion recognition and understanding were assessed at baseline, intervention, and one month post-intervention to determine maintenance effects. Social validity was assessed through parent and teacher questionnaires. All participants showed improvements in measures assessing their recognition of emotions in faces, generalized knowledge to live models, and maintained gains one month post intervention. These preliminary results are encouraging and should be utilized to inform a group design, in order to test efficacy with a larger population. Copyright © 2017 Elsevier Ltd. All rights reserved.

Construction of an alkaline phosphatase-specific two-photon probe and its imaging application in living cells and tissues.

PubMed

Zhang, Huatang; Xiao, Peng; Wong, Yin Ting; Shen, Wei; Chhabra, Mohit; Peltier, Raoul; Jiang, Yin; He, Yonghe; He, Jun; Tan, Yi; Xie, Yusheng; Ho, Derek; Lam, Yun-Wah; Sun, Jinpeng; Sun, Hongyan

2017-09-01

Alkaline phosphatase (ALP) is a family of enzymes involved in the regulation of important biological processes such as cell differentiation and bone mineralization. Monitoring the activity of ALP in serum can help diagnose a variety of diseases including bone and liver diseases. There has been growing interest in developing new chemical tools for monitoring ALP activity in living systems. Such tools will help further delineate the roles of ALP in biological and pathological processes. Previously reported fluorescent probes has a number of disadvantages that limit their application, such as poor selectivity and short-wavelength excitation. In this work, we report a new two-photon fluorescent probe (TP-Phos) to selectively detect ALP activity. The probe is composed of a two-photon fluorophore, a phosphate recognition moiety, and a self-cleavable adaptor. It offers a number of advantages over previously reported probes, such as fast reaction kinetics, high sensitivity and low cytotoxicity. Experimental results also showed that TP-Phos displayed improved selectivity over DIFMUP, a commonly utilized ALP probe. The selectivity is attributed to the utilization of an ortho-functionalised phenyl phosphate group, which increases the steric hindrance of the probe and the active site of phosphatases. Moreover, the two-photon nature of the probe confers enhanced imaging properties such as increased penetration depth and lower tissue autofluorescence. TP-Phos was successfully used to image the endogenous ALP activity of hippocampus, kidney and liver tissues from rat. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantifying Nucleic Acid Ensembles with X-ray Scattering Interferometry.

PubMed

Shi, Xuesong; Bonilla, Steve; Herschlag, Daniel; Harbury, Pehr

2015-01-01

The conformational ensemble of a macromolecule is the complete description of the macromolecule's solution structures and can reveal important aspects of macromolecular folding, recognition, and function. However, most experimental approaches determine an average or predominant structure, or follow transitions between states that each can only be described by an average structure. Ensembles have been extremely difficult to experimentally characterize. We present the unique advantages and capabilities of a new biophysical technique, X-ray scattering interferometry (XSI), for probing and quantifying structural ensembles. XSI measures the interference of scattered waves from two heavy metal probes attached site specifically to a macromolecule. A Fourier transform of the interference pattern gives the fractional abundance of different probe separations directly representing the multiple conformation states populated by the macromolecule. These probe-probe distance distributions can then be used to define the structural ensemble of the macromolecule. XSI provides accurate, calibrated distance in a model-independent fashion with angstrom scale sensitivity in distances. XSI data can be compared in a straightforward manner to atomic coordinates determined experimentally or predicted by molecular dynamics simulations. We describe the conceptual framework for XSI and provide a detailed protocol for carrying out an XSI experiment. © 2015 Elsevier Inc. All rights reserved.

In vivo subsurface morphological and functional cellular and subcellular imaging of the gastrointestinal tract with confocal mini-microscopy

PubMed Central

Goetz, Martin; Memadathil, Beena; Biesterfeld, Stefan; Schneider, Constantin; Gregor, Sebastian; Galle, Peter R; Neurath, Markus F; Kiesslich, Ralf

2007-01-01

AIM: To evaluate a newly developed hand-held confocal probe for in vivo microscopic imaging of the complete gastrointestinal tract in rodents. METHODS: A novel rigid confocal probe (diameter 7 mm) was designed with optical features similar to the flexible endomicroscopy system for use in humans using a 488 nm single line laser for fluorophore excitation. Light emission was detected at 505 to 750 nm. The field of view was 475 μm × 475 μm. Optical slice thickness was 7 μm with a lateral resolution of 0.7 μm. Subsurface serial images at different depths (surface to 250 μm) were generated in real time at 1024 × 1024 pixels (0.8 frames/s) by placing the probe onto the tissue in gentle, stable contact. Tissue specimens were sampled for histopathological correlation. RESULTS: The esophagus, stomach, small and large intestine and meso, liver, pancreas and gall bladder were visualised in vivo at high resolution in n = 48 mice. Real time microscopic imaging with the confocal mini-microscopy probe was easy to achieve. The different staining protocols (fluorescein, acriflavine, FITC-labelled dextran and L. esculentum lectin) each highlighted specific aspects of the tissue, and in vivo imaging correlated excellently with conventional histology. In vivo blood flow monitoring added a functional quality to morphologic imaging. CONCLUSION: Confocal microscopy is feasible in vivo allowing the visualisation of the complete GI tract at high resolution even of subsurface tissue structures. The new confocal probe design evaluated in this study is compatible with laparoscopy and significantly expands the field of possible applications to intra-abdominal organs. It allows immediate testing of new in vivo staining and application options and therefore permits rapid transfer from animal studies to clinical use in patients. PMID:17465494

Window-based method for approximating the Hausdorff in three-dimensional range imagery

DOEpatents

Koch, Mark W [Albuquerque, NM

2009-06-02

One approach to pattern recognition is to use a template from a database of objects and match it to a probe image containing the unknown. Accordingly, the Hausdorff distance can be used to measure the similarity of two sets of points. In particular, the Hausdorff can measure the goodness of a match in the presence of occlusion, clutter, and noise. However, existing 3D algorithms for calculating the Hausdorff are computationally intensive, making them impractical for pattern recognition that requires scanning of large databases. The present invention is directed to a new method that can efficiently, in time and memory, compute the Hausdorff for 3D range imagery. The method uses a window-based approach.

Chemical Posttranslational Modification with Designed Rhodium(II) Catalysts.

PubMed

Martin, S C; Minus, M B; Ball, Z T

2016-01-01

Natural enzymes use molecular recognition to perform exquisitely selective transformations on nucleic acids, proteins, and natural products. Rhodium(II) catalysts mimic this selectivity, using molecular recognition to allow selective modification of proteins with a variety of functionalized diazo reagents. The rhodium catalysts and the diazo reactivity have been successfully applied to a variety of protein folds, the chemistry succeeds in complex environments such as cell lysate, and a simple protein blot method accurately assesses modification efficiency. The studies with rhodium catalysts provide a new tool to study and probe protein-binding events, as well as a new synthetic approach to protein conjugates for medical, biochemical, or materials applications. © 2016 Elsevier Inc. All rights reserved.

Determination of cell metabolite VEGF₁₆₅ and dynamic analysis of protein-DNA interactions by combination of microfluidic technique and luminescent switch-on probe.

PubMed

Lin, Xuexia; Leung, Ka-Ho; Lin, Ling; Lin, Luyao; Lin, Sheng; Leung, Chung-Hang; Ma, Dik-Lung; Lin, Jin-Ming

2016-05-15

In this paper, we rationally design a novel G-quadruplex-selective luminescent iridium (III) complex for rapid detection of oligonucleotide and VEGF165 in microfluidics. This new probe is applied as a convenient biosensor for label-free quantitative analysis of VEGF165 protein from cell metabolism, as well as for studying the kinetics of the aptamer-protein interaction combination with a microfluidic platform. As a result, we have successfully established a quantitative analysis of VEGF165 from cell metabolism. Furthermore, based on the principles of hydrodynamic focusing and diffusive mixing, different transient states during kinetics process were monitored and recorded. Thus, the combination of microfluidic technique and G-quadruplex luminescent probe will be potentially applied in the studies of intramolecular interactions and molecule recognition in the future. Copyright © 2015 Elsevier B.V. All rights reserved.

A novel colorimetric and turn-on fluorescent chemosensor for iron(III) ion detection and its application to cellular imaging

NASA Astrophysics Data System (ADS)

Luo, Aoheng; Wang, Hongqing; Wang, Yuyuan; Huang, Qiao; Zhang, Qin

2016-11-01

A novel rhodamine-based dual probe Rh-2 for trivalent ferric ions (Fe3 +) was successfully designed and synthesized, which exhibited a highly sensitive and selective recognition towards Fe3 + with an enhanced fluorescence emission in methanol-water media (v/v = 7/3, pH = 7.2). The probe Rh-2 could be applied to the determination of Fe3 + with a linear range covering from 3.0 × 10- 7 to 1.4 × 10- 5 M and a detection limit of 1.24 × 10- 8 M. Meanwhile, the binding ratio of Rh-2 and Fe3 + was found to be 1:1. Most importantly, the fluorescence and color signal changes of the Rh-2 solution were specific to Fe3 + over other commonly coexistent metal ions. Moreover, the probe Rh-2 has been used to image Fe3 + in living cells with satisfying results.

Small molecule chemical probes of microRNA function.

PubMed

Velagapudi, Sai Pradeep; Vummidi, Balayeshwanth R; Disney, Matthew D

2015-02-01

MicroRNAs (miRNAs) are small, non-coding RNAs that control protein expression. Aberrant miRNA expression has been linked to various human diseases, and thus miRNAs have been explored as diagnostic markers and therapeutic targets. Although it is challenging to target RNA with small molecules in general, there have been successful campaigns that have identified small molecule modulators of miRNA function by targeting various pathways. For example, small molecules that modulate transcription and target nuclease processing sites in miRNA precursors have been identified. Herein, we describe challenges in developing chemical probes that target miRNAs and highlight aspects of miRNA cellular biology elucidated by using small molecule chemical probes. We expect that this area will expand dramatically in the near future as progress is made in understanding small molecule recognition of RNA. Copyright © 2014. Published by Elsevier Ltd.

Predicting First Grade Achievement from Kindergarten Screening Measures: A Comparison of Child and Family Predictors.

ERIC Educational Resources Information Center

Bramlett, Ronald K.; Rowell, R. Kevin; Mandenberg, Kristi

2000-01-01

Compared the Parenting Stress Index (R. Abidon, 1990), the Behavior Assessment System for Children (C. Reynolds and R. Kamphaus, 1992), and an informal letter/number probe as predictors of first grade reading and mathematics achievement for 92 children early in the kindergarten year. Results show that number and letter recognition were the best…

Burst-mode optical label processor with ultralow power consumption.

PubMed

Ibrahim, Salah; Nakahara, Tatsushi; Ishikawa, Hiroshi; Takahashi, Ryo

2016-04-04

A novel label processor subsystem for 100-Gbps (25-Gbps × 4λs) burst-mode optical packets is developed, in which a highly energy-efficient method is pursued for extracting and interfacing the ultrafast packet-label to a CMOS-based processor where label recognition takes place. The method involves performing serial-to-parallel conversion for the label bits on a bit-by-bit basis by using an optoelectronic converter that is operated with a set of optical triggers generated in a burst-mode manner upon packet arrival. Here we present three key achievements that enabled a significant reduction in the total power consumption and latency of the whole subsystem; 1) based on a novel operation mechanism for providing amplification with bit-level selectivity, an optical trigger pulse generator, that consumes power for a very short duration upon packet arrival, is proposed and experimentally demonstrated, 2) the energy of optical triggers needed by the optoelectronic serial-to-parallel converter is reduced by utilizing a negative-polarity signal while employing an enhanced conversion scheme entitled the discharge-or-hold scheme, 3) the necessary optical trigger energy is further cut down by half by coupling the triggers through the chip's backside, whereas a novel lens-free packaging method is developed to enable a low-cost alignment process that works with simple visual observation.

Bulky melamine-based Zn-porphyrin tweezer as a CD probe of molecular chirality.

PubMed

Petrovic, Ana G; Vantomme, Ghislaine; Negrón-Abril, Yashira L; Lubian, Elisa; Saielli, Giacomo; Menegazzo, Ileana; Cordero, Roselynn; Proni, Gloria; Nakanishi, Koji; Carofiglio, Tommaso; Berova, Nina

2011-10-01

The transfer of chirality from a guest molecule to an achiral host is the subject of significant interest especially when, upon chiral induction, the chiroptical response of the host/guest complex can effectively report the absolute configuration (AC) of the guest. For more than a decade, dimeric metalloporphyrin hosts (tweezers) have been successfully applied as chirality probes for determination of the AC for a wide variety of chiral synthetic compounds and natural products. The objective of this study is to investigate the utility of a new class of melamine-bridged Zn-porphyrin tweezers as sensitive AC reporters. A combined approach based on an experimental CD analysis and a theoretical prediction of the prevailing interporphyrin helicity demonstrates that these tweezers display favorable properties for chiral recognition. Herein, we discuss the application of the melamine-bridged tweezer to the chiral recognition of a diverse set of chiral guests, such as 1,2-diamines, α-amino-esters and amides, secondary alcohols, and 1,2-amino-alcohols. The bulky periphery and the presence of a rigid porphyrin linkage lead, in some cases, to a more enhanced CD sensitivity than that reported earlier with other tweezers. Copyright © 2011 Wiley-Liss, Inc.

A VidEo-Based Intelligent Recognition and Decision System for the Phacoemulsification Cataract Surgery.

PubMed

Tian, Shu; Yin, Xu-Cheng; Wang, Zhi-Bin; Zhou, Fang; Hao, Hong-Wei

2015-01-01

The phacoemulsification surgery is one of the most advanced surgeries to treat cataract. However, the conventional surgeries are always with low automatic level of operation and over reliance on the ability of surgeons. Alternatively, one imaginative scene is to use video processing and pattern recognition technologies to automatically detect the cataract grade and intelligently control the release of the ultrasonic energy while operating. Unlike cataract grading in the diagnosis system with static images, complicated background, unexpected noise, and varied information are always introduced in dynamic videos of the surgery. Here we develop a Video-Based Intelligent Recognitionand Decision (VeBIRD) system, which breaks new ground by providing a generic framework for automatically tracking the operation process and classifying the cataract grade in microscope videos of the phacoemulsification cataract surgery. VeBIRD comprises a robust eye (iris) detector with randomized Hough transform to precisely locate the eye in the noise background, an effective probe tracker with Tracking-Learning-Detection to thereafter track the operation probe in the dynamic process, and an intelligent decider with discriminative learning to finally recognize the cataract grade in the complicated video. Experiments with a variety of real microscope videos of phacoemulsification verify VeBIRD's effectiveness.

A VidEo-Based Intelligent Recognition and Decision System for the Phacoemulsification Cataract Surgery

PubMed Central

Yin, Xu-Cheng; Wang, Zhi-Bin; Zhou, Fang; Hao, Hong-Wei

2015-01-01

The phacoemulsification surgery is one of the most advanced surgeries to treat cataract. However, the conventional surgeries are always with low automatic level of operation and over reliance on the ability of surgeons. Alternatively, one imaginative scene is to use video processing and pattern recognition technologies to automatically detect the cataract grade and intelligently control the release of the ultrasonic energy while operating. Unlike cataract grading in the diagnosis system with static images, complicated background, unexpected noise, and varied information are always introduced in dynamic videos of the surgery. Here we develop a Video-Based Intelligent Recognitionand Decision (VeBIRD) system, which breaks new ground by providing a generic framework for automatically tracking the operation process and classifying the cataract grade in microscope videos of the phacoemulsification cataract surgery. VeBIRD comprises a robust eye (iris) detector with randomized Hough transform to precisely locate the eye in the noise background, an effective probe tracker with Tracking-Learning-Detection to thereafter track the operation probe in the dynamic process, and an intelligent decider with discriminative learning to finally recognize the cataract grade in the complicated video. Experiments with a variety of real microscope videos of phacoemulsification verify VeBIRD's effectiveness. PMID:26693249

Attention and memory bias to facial emotions underlying negative symptoms of schizophrenia.

PubMed

Jang, Seon-Kyeong; Park, Seon-Cheol; Lee, Seung-Hwan; Cho, Yang Seok; Choi, Kee-Hong

2016-01-01

This study assessed bias in selective attention to facial emotions in negative symptoms of schizophrenia and its influence on subsequent memory for facial emotions. Thirty people with schizophrenia who had high and low levels of negative symptoms (n = 15, respectively) and 21 healthy controls completed a visual probe detection task investigating selective attention bias (happy, sad, and angry faces randomly presented for 50, 500, or 1000 ms). A yes/no incidental facial memory task was then completed. Attention bias scores and recognition errors were calculated. Those with high negative symptoms exhibited reduced attention to emotional faces relative to neutral faces; those with low negative symptoms showed the opposite pattern when faces were presented for 500 ms regardless of the valence. Compared to healthy controls, those with high negative symptoms made more errors for happy faces in the memory task. Reduced attention to emotional faces in the probe detection task was significantly associated with less pleasure and motivation and more recognition errors for happy faces in schizophrenia group only. Attention bias away from emotional information relatively early in the attentional process and associated diminished positive memory may relate to pathological mechanisms for negative symptoms.

Monkeys show recognition without priming in a classification task

PubMed Central

Basile, Benjamin M.; Hampton, Robert R.

2012-01-01

Humans show visual perceptual priming by identifying degraded images faster and more accurately if they have seen the original images, while simultaneously failing to recognize the same images. Such priming is commonly thought, with little evidence, to be widely distributed phylogenetically. Following Brodbeck (1997), we trained rhesus monkeys (Macaca mulatta) to categorize photographs according to content (e.g., birds, fish, flowers, people). In probe trials, we tested whether monkeys were faster or more accurate at categorizing degraded versions of previously seen images (primed) than degraded versions of novel images (unprimed). Monkeys categorized reliably, but showed no benefit from having previously seen the images. This finding was robust across manipulations of image quality (color, grayscale, line drawings), type of image degradation (occlusion, blurring), levels of processing, and number of repetitions of the prime. By contrast, in probe matching-to-sample trials, monkeys recognized the primes, demonstrating that they remembered the primes and could discriminate them from other images in the same category under the conditions used to test for priming. Two experiments that replicated Brodbeck’s (1997) procedures also produced no evidence of priming. This inability to find priming in monkeys under perceptual conditions sufficient for recognition presents a puzzle. PMID:22975587

New Approaches Towards Recognition of Nucleic Acid Triple Helices

PubMed Central

Arya, Dev P.

2012-01-01

We show that groove recognition of nucleic acid triple helices can be achieved with aminosugars. Among these aminosugars, neomycin is the most effective aminoglycoside (groove binder) for stabilizing a DNA triple helix. It stabilizes both the T·A·T triplex and mixed-base DNA triplexes better than known DNA minor groove binders (which usually destabilize the triplex) and polyamines. Neomycin selectively stabilizes the triplex (T·A·T and mixed base) without any effect on the DNA duplex. The selectivity of neomycin likely originates from its potential and shape complementarity to the triplex Watson–Hoogsteen groove, making it the first molecule that selectively recognizes a triplex groove over a duplex groove. The groove recognition of aminoglycosides is not limited to DNA triplexes, but also extends to RNA and hybrid triple helical structures. Intercalator–neomycin conjugates are shown to simultaneously probe the base stacking and groove surface in the DNA triplex. Calorimetric and spectrosocopic studies allow the quantification of the effect of surface area of the intercalating moiety on binding to the triplex. These studies outline a novel approach to the recognition of DNA triplexes that incorporates the use of non-competing binding sites. These principles of dual recognition should be applicable to the design of ligands that can bind any given nucleic acid target with nanomolar affinities and with high selectivity. PMID:21073199

MDMA (Ecstasy) use is associated with reduced BOLD signal change during semantic recognition in abstinent human polydrug users: a preliminary fMRI study

PubMed Central

Raj, Vidya; Liang, Han-Chun; Woodward, Neil D.; Bauernfeind, Amy L.; Lee, Junghee; Dietrich, Mary; Park, Sohee; Cowan, Ronald L.

2011-01-01

Objectives MDMA users have impaired verbal memory, and voxel-based morphometry has demonstrated decreased gray matter in Brodmann area (BA) 18, 21 and 45. Because these regions play a role in verbal memory, we hypothesized that MDMA users would show altered brain activation in these areas during performance of an fMRI task that probed semantic verbal memory. Methods Polysubstance users enriched for MDMA exposure participated in a semantic memory encoding and recognition fMRI task that activated left BA 9, 18, 21/22 and 45. Primary outcomes were percent BOLD signal change in left BA 9, 18, 21/22 and 45, accuracy and response time. Results During semantic recognition, lifetime MDMA use was associated with decreased activation in left BA 9, 18 and 21/22 but not 45. This was partly influenced by contributions from cannabis and cocaine use. MDMA exposure was not associated with accuracy or response time during the semantic recognition task. Conclusions During semantic recognition, MDMA exposure is associated with reduced regional brain activation in regions mediating verbal memory. These findings partially overlap with prior structural evidence for reduced gray matter in MDMA users and may, in part, explain the consistent verbal memory impairments observed in other studies of MDMA users. PMID:19304866

Dual recognition unit strategy improves the specificity of the adenosine triphosphate (ATP) aptamer biosensor for cerebral ATP assay.

PubMed

Yu, Ping; He, Xiulan; Zhang, Li; Mao, Lanqun

2015-01-20

Adenosine triphosphate (ATP) aptamer has been widely used as a recognition unit for biosensor development; however, its relatively poor specificity toward ATP against adenosine-5'-diphosphate (ADP) and adenosine-5'-monophosphate (AMP) essentially limits the application of the biosensors in real systems, especially in the complex cerebral system. In this study, for the first time, we demonstrate a dual recognition unit strategy (DRUS) to construct a highly selective and sensitive ATP biosensor by combining the recognition ability of aptamer toward A nucleobase and of polyimidazolium toward phosphate. The biosensors are constructed by first confining the polyimidazolium onto a gold surface by surface-initiated atom transfer radical polymerization (SI-ATRP), and then the aptamer onto electrode surface by electrostatic self-assembly to form dual-recognition-unit-functionalized electrodes. The constructed biosensor based on DRUS not only shows an ultrahigh sensitivity toward ATP with a detection limit down to the subattomole level but also an ultrahigh selectivity toward ATP without interference from ADP and AMP. The constructed biosensor is used for selective and sensitive sensing of the extracellular ATP in the cerebral system by combining in vivo microdialysis and can be used as a promising neurotechnology to probing cerebral ATP concentration.

Top-down modulation of ventral occipito-temporal responses during visual word recognition.

PubMed

Twomey, Tae; Kawabata Duncan, Keith J; Price, Cathy J; Devlin, Joseph T

2011-04-01

Although interactivity is considered a fundamental principle of cognitive (and computational) models of reading, it has received far less attention in neural models of reading that instead focus on serial stages of feed-forward processing from visual input to orthographic processing to accessing the corresponding phonological and semantic information. In particular, the left ventral occipito-temporal (vOT) cortex is proposed to be the first stage where visual word recognition occurs prior to accessing nonvisual information such as semantics and phonology. We used functional magnetic resonance imaging (fMRI) to investigate whether there is evidence that activation in vOT is influenced top-down by the interaction of visual and nonvisual properties of the stimuli during visual word recognition tasks. Participants performed two different types of lexical decision tasks that focused on either visual or nonvisual properties of the word or word-like stimuli. The design allowed us to investigate how vOT activation during visual word recognition was influenced by a task change to the same stimuli and by a stimulus change during the same task. We found both stimulus- and task-driven modulation of vOT activation that can only be explained by top-down processing of nonvisual aspects of the task and stimuli. Our results are consistent with the hypothesis that vOT acts as an interface linking visual form with nonvisual processing in both bottom up and top down directions. Such interactive processing at the neural level is in agreement with cognitive and computational models of reading but challenges some of the assumptions made by current neuro-anatomical models of reading. Copyright © 2011 Elsevier Inc. All rights reserved.

Relationship between slow visual processing and reading speed in people with macular degeneration

PubMed Central

Cheong, Allen MY; Legge, Gordon E; Lawrence, Mary G; Cheung, Sing-Hang; Ruff, Mary A

2007-01-01

Purpose People with macular degeneration (MD) often read slowly even with adequate magnification to compensate for acuity loss. Oculomotor deficits may affect reading in MD, but cannot fully explain the substantial reduction in reading speed. Central-field loss (CFL) is often a consequence of macular degeneration, necessitating the use of peripheral vision for reading. We hypothesized that slower temporal processing of visual patterns in peripheral vision is a factor contributing to slow reading performance in MD patients. Methods Fifteen subjects with MD, including 12 with CFL, and five age-matched control subjects were recruited. Maximum reading speed and critical print size were measured with RSVP (Rapid Serial Visual Presentation). Temporal processing speed was studied by measuring letter-recognition accuracy for strings of three randomly selected letters centered at fixation for a range of exposure times. Temporal threshold was defined as the exposure time yielding 80% recognition accuracy for the central letter. Results Temporal thresholds for the MD subjects ranged from 159 to 5881 ms, much longer than values for age-matched controls in central vision (13 ms, p<0.01). The mean temporal threshold for the 11 MD subjects who used eccentric fixation (1555.8 ± 1708.4 ms) was much longer than the mean temporal threshold (97.0 ms ± 34.2 ms, p<0.01) for the age-matched controls at 10° in the lower visual field. Individual temporal thresholds accounted for 30% of the variance in reading speed (p<0.05). Conclusion The significant association between increased temporal threshold for letter recognition and reduced reading speed is consistent with the hypothesis that slower visual processing of letter recognition is one of the factors limiting reading speed in MD subjects. PMID:17881032

A lysosome-targetable turn-on fluorescent probe for the detection of thiols in living cells based on a 1,8-naphthalimide derivative

NASA Astrophysics Data System (ADS)

Liang, Beibei; Wang, Baiyan; Ma, Qiujuan; Xie, Caixia; Li, Xian; Wang, Suiping

2018-03-01

Biological thiols, like cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), play crucial roles in biological systems and in lysosomal processes. Highly selective probes for detecting biological thiols in lysomes of living cells are rare. In this work, a lysosome-targetable turn-on fluorescent probe for the detection of thiols in living cells was designed and synthesized based on a 1,8-naphthalimide derivative. The probe has a 4-(2-aminoethyl)morpholine unit as a lysosome-targetable group and an acrylate group as the thiol recognition unit as well as a fluorescence quencher. In the absence of biothiols, the probe displayed weak fluorescence due to the photoinduced electron transfer (PET) process. Upon the addition of biothiols, the probe exhibited an enhanced fluorescence emission centered at 550 nm due to cleavage of the acrylate moiety. The probe had high selectivity toward biothiols. Moreover, the probe features fast response time, excitation in the visible region and ability of working in a wide pH range. The linear response range covers a concentration range of Cys from 1.5 × 10- 7 to 1.0 × 10- 5 mol·L- 1 and the detection limit is 6.9 × 10- 8 mol·L- 1 for Cys. The probe has been successfully applied to the confocal imaging of biothiols in lysosomes of A549 cells with low cell toxicity. Furthermore, the method was successfully applied to the determination of thiols in a complex multicomponent mixture such as human serum, which suggests our proposed method has great potential for diagnostic purposes. All of such good properties prove it can be used to monitor biothiols in lysosomes of living cells and to be a good fluorescent probe for the selective detection of thiols.

Customized Molecular Phenotyping by Quantitative Gene Expression and Pattern Recognition Analysis

PubMed Central

Akilesh, Shreeram; Shaffer, Daniel J.; Roopenian, Derry

2003-01-01

Description of the molecular phenotypes of pathobiological processes in vivo is a pressing need in genomic biology. We have implemented a high-throughput real-time PCR strategy to establish quantitative expression profiles of a customized set of target genes. It enables rapid, reproducible data acquisition from limited quantities of RNA, permitting serial sampling of mouse blood during disease progression. We developed an easy to use statistical algorithm—Global Pattern Recognition—to readily identify genes whose expression has changed significantly from healthy baseline profiles. This approach provides unique molecular signatures for rheumatoid arthritis, systemic lupus erythematosus, and graft versus host disease, and can also be applied to defining the molecular phenotype of a variety of other normal and pathological processes. PMID:12840047

Monopolar Detection Thresholds Predict Spatial Selectivity of Neural Excitation in Cochlear Implants: Implications for Speech Recognition

PubMed Central

2016-01-01

The objectives of the study were to (1) investigate the potential of using monopolar psychophysical detection thresholds for estimating spatial selectivity of neural excitation with cochlear implants and to (2) examine the effect of site removal on speech recognition based on the threshold measure. Detection thresholds were measured in Cochlear Nucleus® device users using monopolar stimulation for pulse trains that were of (a) low rate and long duration, (b) high rate and short duration, and (c) high rate and long duration. Spatial selectivity of neural excitation was estimated by a forward-masking paradigm, where the probe threshold elevation in the presence of a forward masker was measured as a function of masker-probe separation. The strength of the correlation between the monopolar thresholds and the slopes of the masking patterns systematically reduced as neural response of the threshold stimulus involved interpulse interactions (refractoriness and sub-threshold adaptation), and spike-rate adaptation. Detection threshold for the low-rate stimulus most strongly correlated with the spread of forward masking patterns and the correlation reduced for long and high rate pulse trains. The low-rate thresholds were then measured for all electrodes across the array for each subject. Subsequently, speech recognition was tested with experimental maps that deactivated five stimulation sites with the highest thresholds and five randomly chosen ones. Performance with deactivating the high-threshold sites was better than performance with the subjects’ clinical map used every day with all electrodes active, in both quiet and background noise. Performance with random deactivation was on average poorer than that with the clinical map but the difference was not significant. These results suggested that the monopolar low-rate thresholds are related to the spatial neural excitation patterns in cochlear implant users and can be used to select sites for more optimal speech recognition performance. PMID:27798658

Contrasting visual working memory for verbal and non-verbal material with multivariate analysis of fMRI

PubMed Central

Habeck, Christian; Rakitin, Brian; Steffener, Jason; Stern, Yaakov

2012-01-01

We performed a delayed-item-recognition task to investigate the neural substrates of non-verbal visual working memory with event-related fMRI (‘Shape task’). 25 young subjects (mean age: 24.0 years; STD=3.8 years) were instructed to study a list of either 1,2 or 3 unnamable nonsense line drawings for 3 seconds (‘stimulus phase’ or STIM). Subsequently, the screen went blank for 7 seconds (‘retention phase’ or RET), and then displayed a probe stimulus for 3 seconds in which subject indicated with a differential button press whether the probe was contained in the studied shape-array or not (‘probe phase’ or PROBE). Ordinal Trend Canonical Variates Analysis (Habeck et al., 2005a) was performed to identify spatial covariance patterns that showed a monotonic increase in expression with memory load during all task phases. Reliable load-related patterns were identified in the stimulus and retention phase (p<0.01), while no significant pattern could be discerned during the probe phase. Spatial covariance patterns that were obtained from an earlier version of this task (Habeck et al., 2005b) using 1, 3, or 6 letters (‘Letter task’) were also prospectively applied to their corresponding task phases in the current non-verbal task version. Interestingly, subject expression of covariance patterns from both verbal and non-verbal retention phases correlated positively in the non-verbal task for all memory loads (p<0.0001). Both patterns also involved similar frontoparietal brain regions that were increasing in activity with memory load, and mediofrontal and temporal regions that were decreasing. Mean subject expression of both patterns across memory load during retention also correlated positively with recognition accuracy (dL) in the Shape task (p<0.005). These findings point to similarities in the neural substrates of verbal and non-verbal rehearsal processes. Encoding processes, on the other hand, are critically dependent on the to-be-remembered material, and seem to necessitate material-specific neural substrates. PMID:22652306

A turn-on coordination nanoparticle-based fluorescent probe for phosphate in human serum

NASA Astrophysics Data System (ADS)

Lin, Na; Li, Jian; Lu, Zhixiang; Bian, Longchun; Zheng, Liyan; Cao, Qiue; Ding, Zhongtao

2015-03-01

Coordination nanoparticles (CNPs) are becoming attractive platforms for chemical sensing applications because their unique adjustable properties offer the opportunity to design various luminescent nanoprobes. Here, we present a CNP-based fluorescent nanoprobe, in which fluorophores (rhodamine B, RB) and quenchers (methylene blue, MB) were spontaneously enfolded by coordination networks self-assembled of adenine, biphenyl-4,4'-dicarboxylic acid (BDA) and zinc ions. The aggregation of fluorophores and quenchers in CNPs resulted in a quenched state fluorescence of RB. RB and MB could be released from CNPs in the presence of phosphate, which triggered the fluorescence of RB. On the basis of recognition-driven disassembly principle, a novel turn-on fluorescent probe for the determination of PO43- with a wide response range (0.5-50 μM) has been successfully applied in the detection of phosphate in human serum samples. This work not only develops a probe for phosphate but also provides a general strategy for designing nanoprobes or nanocarriers towards various targets by altering organic linkers or metal ions.Coordination nanoparticles (CNPs) are becoming attractive platforms for chemical sensing applications because their unique adjustable properties offer the opportunity to design various luminescent nanoprobes. Here, we present a CNP-based fluorescent nanoprobe, in which fluorophores (rhodamine B, RB) and quenchers (methylene blue, MB) were spontaneously enfolded by coordination networks self-assembled of adenine, biphenyl-4,4'-dicarboxylic acid (BDA) and zinc ions. The aggregation of fluorophores and quenchers in CNPs resulted in a quenched state fluorescence of RB. RB and MB could be released from CNPs in the presence of phosphate, which triggered the fluorescence of RB. On the basis of recognition-driven disassembly principle, a novel turn-on fluorescent probe for the determination of PO43- with a wide response range (0.5-50 μM) has been successfully applied in the detection of phosphate in human serum samples. This work not only develops a probe for phosphate but also provides a general strategy for designing nanoprobes or nanocarriers towards various targets by altering organic linkers or metal ions. Electronic supplementary information (ESI) available: Supplementary figures. See DOI: 10.1039/c5nr00515a

A novel "signal-on/off" sensing platform for selective detection of thrombin based on target-induced ratiometric electrochemical biosensing and bio-bar-coded nanoprobe amplification strategy.

PubMed

Wang, Lanlan; Ma, Rongna; Jiang, Liushan; Jia, Liping; Jia, Wenli; Wang, Huaisheng

2017-06-15

A novel dual-signal ratiometric electrochemical aptasensor for highly sensitive and selective detection of thrombin has been designed on the basis of signal-on and signal-off strategy. Ferrocene labeled hairpin probe (Fc-HP), thrombin aptamer and methyl blue labeled bio-bar-coded AuNPs (MB-P3-AuNPs) were rationally introduced for the construction of the assay platform, which combined the advantages of the recognition of aptamer, the amplification of bio-bar-coded nanoprobe, and the ratiometric signaling readout. In the presence of thrombin, the interaction between thrombin and the aptamer leads to the departure of MB-P3-AuNPs from the sensing interface, and the conformation of the single stranded Fc-HP to a hairpin structure to take the Fc confined near the electrode surface. Such conformational changes resulted in the oxidation current of Fc increased and that of MB decreased. Therefore, the recognition event of the target can be dual-signal ratiometric electrochemical readout in both the "signal-off" of MB and the "signal-on" of Fc. The proposed strategy showed a wide linear detection range from 0.003 to 30nM with a detection limit of 1.1 pM. Moreover, it exhibits good performance of excellent selectivity, good stability, and acceptable fabrication reproducibility. By changing the recognition probe, this protocol could be easily expanded into the detection of other targets, showing promising potential applications in disease diagnostics and bioanalysis. Copyright © 2016. Published by Elsevier B.V.

Biometric correspondence between reface computerized facial approximations and CT-derived ground truth skin surface models objectively examined using an automated facial recognition system.

PubMed

Parks, Connie L; Monson, Keith L

2018-05-01

This study employed an automated facial recognition system as a means of objectively evaluating biometric correspondence between a ReFace facial approximation and the computed tomography (CT) derived ground truth skin surface of the same individual. High rates of biometric correspondence were observed, irrespective of rank class (R k ) or demographic cohort examined. Overall, 48% of the test subjects' ReFace approximation probes (n=96) were matched to his or her corresponding ground truth skin surface image at R 1 , a rank indicating a high degree of biometric correspondence and a potential positive identification. Identification rates improved with each successively broader rank class (R 10 =85%, R 25 =96%, and R 50 =99%), with 100% identification by R 57 . A sharp increase (39% mean increase) in identification rates was observed between R 1 and R 10 across most rank classes and demographic cohorts. In contrast, significantly lower (p<0.01) increases in identification rates were observed between R 10 and R 25 (8% mean increase) and R 25 and R 50 (3% mean increase). No significant (p>0.05) performance differences were observed across demographic cohorts or CT scan protocols. Performance measures observed in this research suggest that ReFace approximations are biometrically similar to the actual faces of the approximated individuals and, therefore, may have potential operational utility in contexts in which computerized approximations are utilized as probes in automated facial recognition systems. Copyright © 2018. Published by Elsevier B.V.

Ultra-fast Movies Resolve Ultra-short Pulse Laser Ablation and Bump Formation on Thin Molybdenum Films

NASA Astrophysics Data System (ADS)

Domke, Matthias; Rapp, Stephan; Huber, Heinz

For the monolithic serial interconnection of CIS thin film solar cells, 470 nm molybdenum films on glass substrates must be separated galvanically. The single pulse ablation with a 660 fs laser at a wavelength of 1053 nm is investigated in a fluence regime from 0.5 to 5.0 J/cm2. At fluences above 2.0 J/cm2 bump and jet formation can be observed that could be used for creating microstructures. For the investigation of the underlying mechanisms of the laser ablation process itself as well as of the bump or jet formation, pump probe microscopy is utilized to resolve the transient ablation behavior.

Comparative evaluation of transmembrane ion transport due to monopolar and bipolar nanosecond, high-intensity electroporation pulses based on full three-dimensional analyses

NASA Astrophysics Data System (ADS)

Hu, Q.; Joshi, R. P.

2017-07-01

Electric pulse driven membrane poration finds applications in the fields of biomedical engineering and drug/gene delivery. Here we focus on nanosecond, high-intensity electroporation and probe the role of pulse shape (e.g., monopolar-vs-bipolar), multiple electrode scenarios, and serial-versus-simultaneous pulsing, based on a three-dimensional time-dependent continuum model in a systematic fashion. Our results indicate that monopolar pulsing always leads to higher and stronger cellular uptake. This prediction is in agreement with experimental reports and observations. It is also demonstrated that multi-pronged electrode configurations influence and increase the degree of cellular uptake.

Item-specific proactive interference in olfactory working memory.

PubMed

Moss, Andrew; Miles, Christopher; Elsley, Jane; Johnson, Andrew

2018-04-01

We examine item-specific olfactory proactive interference (PI) effects and undertake comparisons with verbal and non-verbal visual stimuli. Using a sequential recent-probes task, we show no evidence for PI with hard-to-name odours (Experiment 1). However, verbalisable odours do exhibit PI effects (Experiment 2). These findings occur despite above chance performance and similar serial position functions across both tasks. Experiments 3 and 4 apply words and faces, respectively, to our modified procedure, and show that methodological differences cannot explain the null finding in Experiment 1. The extent to which odours exhibit analogous PI effects to that of other modalities is, we argue, contingent on the characteristics of the odours employed.

Adaptive changes in the neuromagnetic response of the primary and association somatosensory areas following repetitive tactile hand stimulation in humans.

PubMed

Popescu, Elena Anda; Barlow, Steven M; Venkatesan, Lalit; Wang, Jingyan; Popescu, Mihai

2013-06-01

Cortical adaptation in the primary somatosensory cortex (SI) has been probed using different stimulation modalities and recording techniques, in both human and animal studies. In contrast, considerably less knowledge has been gained about the adaptation profiles in other areas of the cortical somatosensory network. Using magnetoencephalography (MEG), we examined the patterns of short-term adaptation for evoked responses in SI and somatosensory association areas during tactile stimulation applied to the glabrous skin of the hand. Cutaneous stimuli were delivered as trains of serial pulses with a constant frequency of 2 Hz and 4 Hz in separate runs, and a constant inter-train interval of 5 s. The unilateral stimuli elicited transient responses to the serial pulses in the train, with several response components that were separated by independent component analysis. Subsequent source reconstruction techniques identified regional generators in the contralateral SI and somatosensory association areas in the posterior parietal cortex (PPC). Activity in the bilateral secondary somatosensory cortex (i.e., SII/PV) was also identified, although less consistently across subjects. The dynamics of the evoked activity in each area and the frequency-dependent adaptation effects were assessed from the changes in the relative amplitude of serial responses in each train. We show that the adaptation profiles in SI and PPC areas can be quantitatively characterized from neuromagnetic recordings using tactile stimulation, with the sensitivity to repetitive stimulation increasing from SI to PPC. A similar approach for SII/PV has proven less straightforward, potentially due to the tendency of these areas to respond selectively to certain stimuli. Copyright © 2011 Wiley Periodicals, Inc.

Accuracy of computer-assisted navigation: significant augmentation by facial recognition software.

PubMed

Glicksman, Jordan T; Reger, Christine; Parasher, Arjun K; Kennedy, David W

2017-09-01

Over the past 20 years, image guidance navigation has been used with increasing frequency as an adjunct during sinus and skull base surgery. These devices commonly utilize surface registration, where varying pressure of the registration probe and loss of contact with the face during the skin tracing process can lead to registration inaccuracies, and the number of registration points incorporated is necessarily limited. The aim of this study was to evaluate the use of novel facial recognition software for image guidance registration. Consecutive adults undergoing endoscopic sinus surgery (ESS) were prospectively studied. Patients underwent image guidance registration via both conventional surface registration and facial recognition software. The accuracy of both registration processes were measured at the head of the middle turbinate (MTH), middle turbinate axilla (MTA), anterior wall of sphenoid sinus (SS), and nasal tip (NT). Forty-five patients were included in this investigation. Facial recognition was accurate to within a mean of 0.47 mm at the MTH, 0.33 mm at the MTA, 0.39 mm at the SS, and 0.36 mm at the NT. Facial recognition was more accurate than surface registration at the MTH by an average of 0.43 mm (p = 0.002), at the MTA by an average of 0.44 mm (p < 0.001), and at the SS by an average of 0.40 mm (p < 0.001). The integration of facial recognition software did not adversely affect registration time. In this prospective study, automated facial recognition software significantly improved the accuracy of image guidance registration when compared to conventional surface registration. © 2017 ARS-AAOA, LLC.

Logical metonymy resolution in a words-as-cues framework: evidence from self-paced reading and probe recognition.

PubMed

Zarcone, Alessandra; Padó, Sebastian; Lenci, Alessandro

2014-06-01

Logical metonymy resolution (begin a book → begin reading a book or begin writing a book) has traditionally been explained either through complex lexical entries (qualia structures) or through the integration of the implicit event via post-lexical access to world knowledge. We propose that recent work within the words-as-cues paradigm can provide a more dynamic model of logical metonymy, accounting for early and dynamic integration of complex event information depending on previous contextual cues (agent and patient). We first present a self-paced reading experiment on German subordinate sentences, where metonymic sentences and their paraphrased version differ only in the presence or absence of the clause-final target verb (Der Konditor begann die Glasur → Der Konditor begann, die Glasur aufzutragen/The baker began the icing → The baker began spreading the icing). Longer reading times at the target verb position in a high-typicality condition (baker + icing → spread ) compared to a low-typicality (but still plausible) condition (child + icing → spread) suggest that we make use of knowledge activated by lexical cues to build expectations about events. The early and dynamic integration of event knowledge in metonymy interpretation is bolstered by further evidence from a second experiment using the probe recognition paradigm. Presenting covert events as probes following a high-typicality or a low-typicality metonymic sentence (Der Konditor begann die Glasur → AUFTRAGEN/The baker began the icing → SPREAD), we obtain an analogous effect of typicality at 100 ms interstimulus interval. © 2014 Cognitive Science Society, Inc.

Probing the dynamic reversibility and generation of dynamic combinatorial libraries in the presence of bacterial model oligopeptides as templating guests of tetra-carbohydrazide macrocycles using electrospray mass spectrometry.

PubMed

Nour, Hany F; Islam, Tuhidul; Fernández-Lahore, Marcelo; Kuhnert, Nikolai

2012-12-30

Over the past few decades, bacterial resistance to antibiotics has emerged as a real threat to human health. Accordingly, there is an urgent demand for the development of innovative strategies for discovering new antibiotics. We present the first use of tetra-carbohydrazide cyclophane macrocycles in dynamic combinatorial chemistry (DCC) and molecular recognition as chiral hosts binding oligopeptides, which mimic bacterial cell wall. This study introduces an innovative application of electrospray ionisation time-of-flight mass spectrometry (ESI-TOF MS) to oligopeptides recognition using DCC. A small dynamic library composed of eight functionalised macrocycles has been generated in solution and all members were characterised by ESI-TOF MS. We also probed the dynamic reversibility and mechanism of formation of tetra-carbohydrazide cyclophanes in real-time using ESI-TOF MS. Dynamic reversibility of tetra-carbohydrazide cyclophanes is favored under thermodynamic control. The mechanism of formation of tetra-carbohydrazide cyclophanes involves key dialdehyde intermediates, which have been detected and assigned according to their high-resolution m/z values. Three members of the dynamic library bind efficiently in the gas phase to a selection of oligopeptides, unique to bacteria, allowing observation of host/guest complex ions in the gas phase. We probed the mechanism of the [2+2]-cyclocondensation reaction forming library members, proved dynamic reversibility of tetra-carbohydrazide cyclophanes and showed that complex ions formed between library members and hosts can be observed in the gas phase, allowing the solution of an important problem of biological interest. Copyright © 2012 John Wiley & Sons, Ltd.

A hybrid analog-digital phase-locked loop for frequency mode non-contact scanning probe microscopy.

PubMed

Mehta, M M; Chandrasekhar, V

2014-01-01

Non-contact scanning probe microscopy (SPM) has developed into a powerful technique to image many different properties of samples. The conventional method involves monitoring the amplitude, phase, or frequency of a cantilever oscillating at or near its resonant frequency as it is scanned across the surface of a sample. For high Q factor cantilevers, monitoring the resonant frequency is the preferred method in order to obtain reasonable scan times. This can be done by using a phase-locked-loop (PLL). PLLs can be obtained as commercial integrated circuits, but these do not have the frequency resolution required for SPM. To increase the resolution, all-digital PLLs requiring sophisticated digital signal processors or field programmable gate arrays have also been implemented. We describe here a hybrid analog/digital PLL where most of the components are implemented using discrete analog integrated circuits, but the frequency resolution is provided by a direct digital synthesis chip controlled by a simple peripheral interface controller (PIC) microcontroller. The PLL has excellent frequency resolution and noise, and can be controlled and read by a computer via a universal serial bus connection.

A hybrid analog-digital phase-locked loop for frequency mode non-contact scanning probe microscopy

NASA Astrophysics Data System (ADS)

Mehta, M. M.; Chandrasekhar, V.

2014-01-01

Non-contact scanning probe microscopy (SPM) has developed into a powerful technique to image many different properties of samples. The conventional method involves monitoring the amplitude, phase, or frequency of a cantilever oscillating at or near its resonant frequency as it is scanned across the surface of a sample. For high Q factor cantilevers, monitoring the resonant frequency is the preferred method in order to obtain reasonable scan times. This can be done by using a phase-locked-loop (PLL). PLLs can be obtained as commercial integrated circuits, but these do not have the frequency resolution required for SPM. To increase the resolution, all-digital PLLs requiring sophisticated digital signal processors or field programmable gate arrays have also been implemented. We describe here a hybrid analog/digital PLL where most of the components are implemented using discrete analog integrated circuits, but the frequency resolution is provided by a direct digital synthesis chip controlled by a simple peripheral interface controller (PIC) microcontroller. The PLL has excellent frequency resolution and noise, and can be controlled and read by a computer via a universal serial bus connection.

[Serum levels of HCV-RNA determined by branched DNA (bDNA) probe assay in chronic hepatitis C: method and clinical significance on interferon (IFN) therapy].

PubMed

Osada, T; Iwabuchi, S; Takatori, M; Murayama, M; Iino, S

1994-07-01

Recently serum levels of HCV RNA (s-HCV RNA) in chronic hepatitis C has been regarded as one of an important indicator for the activity of disease and outcome of IFN therapy. Quantitative analysis by competitive RT-PCR, however, requires special skills and is too expensive for clinical use. We attempted to determine serial sample of s-HCV RNA and genotypes in 117 cases treated with IFN using bDNA probe assay which has lately been developed by Chiron corporation. Cases with complete response to IFN therapy showed 62% (49/79) in lower than 10(6) levels, 27% (8/30) in 10(6)-10(7) and only 5% (2/41) in higher than 10(7). Genotype III, IV had higher response than type II on the same level of s-HCV RNA. These data indicates that determination of s-HCV levels by bDNA assay may be useful for prediction of the outcome of IFN therapy and making adequate schedule of the therapy in each cases.

Analysis of early dengue virus infection in mice as modulated by Aedes aegypti probing.

PubMed

McCracken, M K; Christofferson, R C; Chisenhall, D M; Mores, C N

2014-02-01

Dengue virus (DENV), the etiologic agent of dengue fever, is transmitted during probing of human skin by infected-mosquito bite. The expectorated viral inoculum also contains an assortment of mosquito salivary proteins that have been shown to modulate host hemostasis and innate immune responses. To examine the potential role of mosquito probing in DENV establishment within the vertebrate host, we inoculated mice intradermally with DENV serotype 2 strain 1232 at sites where Aedes aegypti had or had not probed immediately prior. We assayed these sites 3 h postinoculation with transcript arrays for the Toll-like receptor (TLR), RIG-I-like receptor, and NOD-like receptor signaling pathways of the innate immune system. We then chose TLR7, transcription factor p65 (RelA), gamma interferon (IFN-γ), and IFN-γ-inducible protein 10 (IP-10) from the arrays for further investigation and assayed these transcripts at 10 min, 3 h, and 6 h postinoculation. The transcripts for TLR7, RelA, IFN-γ, and IP-10 were significantly downregulated between 2- and 3-fold in the group subjected to mosquito probing relative to the virus-only inoculation group at 3 h postinoculation. A reduction in these transcripts could indicate reduced DENV recognition and antigen presentation and diminished inhibition of viral replication and spread. Further, mosquito probing resulted in viremia titers significantly higher than those in mice that did not receive probing. A. aegypti probing has a significant effect on the innate immune response to DENV infection and generates an early immune environment more permissive to the establishment of infection.

Immobilized OBOC combinatorial bead array to facilitate multiplicative screening.

PubMed

Xiao, Wenwu; Bononi, Fernanda C; Townsend, Jared; Li, Yuanpei; Liu, Ruiwu; Lam, Kit S

2013-07-01

One-bead-one-compound (OBOC) combinatorial library screening has been broadly utilized for the last two decades to identify small molecules, peptides or peptidomimetics targeting variable screening probes such as cell surface receptors, bacteria, protein kinases, phosphatases, proteases etc. In previous screening methods, library beads were suspended in solution and screened against one single probe. Only the positive beads were tracked and isolated for additional screens and finally selected for chemical decoding. During this process, the remaining negative beads were not tracked and discarded. Here we report a novel bead immobilization method such that a bead library array can be conveniently prepared and screened in its entirety, sequentially many times with a series of distinct probes. This method not only allows us to increase the screening efficiency but also permits us to determine the binding profile of each and every library bead against a large number of target receptors. As proof of concept, we serially screened a random OBOC disulfide containing cyclic heptapeptide library with three water soluble dyes as model probes: malachite green, bromocresol purple and indigo carmine. This multiplicative screening approach resulted in a rapid determination of the binding profile of each and every bead respective to each of the three dyes. Beads that interacted with malachite green only, bromocresol purple only, or both indigo carmine and bromocresol purple were isolated, and their peptide sequences were determined with microsequencer. Ultimately, the novel OBOC multiplicative screening approach could play a key role in the enhancement of existing on-bead assays such as whole cell binding, bacteria binding, protein binding, posttranslational modifications etc. with increased efficiency, capacity, and specificity.

Identification of Cyclin A Binders with a Fluorescent Peptide Sensor.

PubMed

Pazos, Elena; Mascareñas, José L; Vázquez, M Eugenio

2016-01-01

A peptide sensor that integrates the 4-dimethylaminophthalimide (4-DMAP) fluorophore in a short cyclin A binding sequence displays a large fluorescence emission increase upon interacting with the cyclin A Binding Groove (CBG). Competitive displacement assays of this probe allow the straightforward identification of peptides that interact with the CBG, which could potentially block the recognition of CDK/cyclin A kinase substrates.

Schools of Excellence and Equity? Using Equity Audits as a Tool to Expose a Flawed System of Recognition

ERIC Educational Resources Information Center

Brown, Kathleen M.

2010-01-01

The purpose of this article is to demonstrate how equity audits can be used as a tool to expose disparate achievement in schools that, on the surface and to the public, appear quite similar. To that end, the researcher probed beyond surface-level performance composite scores into deeper, more hidden data associated with state-recognized…

The “parts and wholes” of face recognition: a review of the literature

PubMed Central

Tanaka, James W.; Simonyi, Diana

2016-01-01

It has been claimed that faces are recognized as a “whole” rather than the recognition of individual parts. In a paper published in the Quarterly Journal of Experimental Psychology in 1993, Martha Farah and I attempted to operationalize the holistic claim using the part/whole task. In this task, participants studied a face and then their memory presented in isolation and in the whole face. Consistent with the holistic view, recognition of the part was superior when tested in the whole-face condition compared to when it was tested in isolation. The “whole face” or holistic advantage was not found for faces that were inverted, or scrambled, nor for non-face objects suggesting that holistic encoding was specific to normal, intact faces. In this paper, we reflect on the part/whole paradigm and how it has contributed to our understanding of what it means to recognize a face as a “whole” stimulus. We describe the value of part/whole task for developing theories of holistic and non-holistic recognition of faces and objects. We discuss the research that has probed the neural substrates of holistic processing in healthy adults and people with prosopagnosia and autism. Finally, we examine how experience shapes holistic face recognition in children and recognition of own- and other-race faces in adults. The goal of this article is to summarize the research on the part/whole task and speculate on how it has informed our understanding of holistic face processing. PMID:26886495

The "parts and wholes" of face recognition: A review of the literature.

PubMed

Tanaka, James W; Simonyi, Diana

2016-10-01

It has been claimed that faces are recognized as a "whole" rather than by the recognition of individual parts. In a paper published in the Quarterly Journal of Experimental Psychology in 1993, Martha Farah and I attempted to operationalize the holistic claim using the part/whole task. In this task, participants studied a face and then their memory presented in isolation and in the whole face. Consistent with the holistic view, recognition of the part was superior when tested in the whole-face condition compared to when it was tested in isolation. The "whole face" or holistic advantage was not found for faces that were inverted, or scrambled, nor for non-face objects, suggesting that holistic encoding was specific to normal, intact faces. In this paper, we reflect on the part/whole paradigm and how it has contributed to our understanding of what it means to recognize a face as a "whole" stimulus. We describe the value of part/whole task for developing theories of holistic and non-holistic recognition of faces and objects. We discuss the research that has probed the neural substrates of holistic processing in healthy adults and people with prosopagnosia and autism. Finally, we examine how experience shapes holistic face recognition in children and recognition of own- and other-race faces in adults. The goal of this article is to summarize the research on the part/whole task and speculate on how it has informed our understanding of holistic face processing.

Recognizing Age-Separated Face Images: Humans and Machines

PubMed Central

Yadav, Daksha; Singh, Richa; Vatsa, Mayank; Noore, Afzel

2014-01-01

Humans utilize facial appearance, gender, expression, aging pattern, and other ancillary information to recognize individuals. It is interesting to observe how humans perceive facial age. Analyzing these properties can help in understanding the phenomenon of facial aging and incorporating the findings can help in designing effective algorithms. Such a study has two components - facial age estimation and age-separated face recognition. Age estimation involves predicting the age of an individual given his/her facial image. On the other hand, age-separated face recognition consists of recognizing an individual given his/her age-separated images. In this research, we investigate which facial cues are utilized by humans for estimating the age of people belonging to various age groups along with analyzing the effect of one's gender, age, and ethnicity on age estimation skills. We also analyze how various facial regions such as binocular and mouth regions influence age estimation and recognition capabilities. Finally, we propose an age-invariant face recognition algorithm that incorporates the knowledge learned from these observations. Key observations of our research are: (1) the age group of newborns and toddlers is easiest to estimate, (2) gender and ethnicity do not affect the judgment of age group estimation, (3) face as a global feature, is essential to achieve good performance in age-separated face recognition, and (4) the proposed algorithm yields improved recognition performance compared to existing algorithms and also outperforms a commercial system in the young image as probe scenario. PMID:25474200

Recognizing age-separated face images: humans and machines.

PubMed

Yadav, Daksha; Singh, Richa; Vatsa, Mayank; Noore, Afzel

2014-01-01

Humans utilize facial appearance, gender, expression, aging pattern, and other ancillary information to recognize individuals. It is interesting to observe how humans perceive facial age. Analyzing these properties can help in understanding the phenomenon of facial aging and incorporating the findings can help in designing effective algorithms. Such a study has two components--facial age estimation and age-separated face recognition. Age estimation involves predicting the age of an individual given his/her facial image. On the other hand, age-separated face recognition consists of recognizing an individual given his/her age-separated images. In this research, we investigate which facial cues are utilized by humans for estimating the age of people belonging to various age groups along with analyzing the effect of one's gender, age, and ethnicity on age estimation skills. We also analyze how various facial regions such as binocular and mouth regions influence age estimation and recognition capabilities. Finally, we propose an age-invariant face recognition algorithm that incorporates the knowledge learned from these observations. Key observations of our research are: (1) the age group of newborns and toddlers is easiest to estimate, (2) gender and ethnicity do not affect the judgment of age group estimation, (3) face as a global feature, is essential to achieve good performance in age-separated face recognition, and (4) the proposed algorithm yields improved recognition performance compared to existing algorithms and also outperforms a commercial system in the young image as probe scenario.

Polymer-mediated immunocamouflage of red blood cells: effects of polymer size on antigenic and immunogenic recognition of allogeneic donor blood cells.

PubMed

Wang, DunCheng; Kyluik, Dana L; Murad, Kari L; Toyofuku, Wendy M; Scott, Mark D

2011-07-01

Developing a practical means of reducing alloimmunization in chronically transfused patients would be of significant clinical benefit. Immunocamouflaging red blood cells (RBCs) by membrane grafting of methoxypoly(ethylene glycol) (mPEG) may reduce the risk of allo-immunization. The results of this study showed that antibody recognition of non-ABO antigens was significantly reduced in an mPEG-dose- and polymer size-dependent manner, with higher molecular weight mPEGs providing better immunoprotection. Furthermore, in vivo immunogenicity was significantly reduced in mice serially transfused with mPEG-modified xenogeneic (sheep; sRBCs), allogeneic (C57Bl/6), or syngeneic (Balb/c) RBCs. Following a primary transfusion of sRBCs, mice receiving mPEG-sRBCs showed a >90% reduction in anti-sRBC IgG antibody levels. After two transfusions, mice receiving mPEG-sRBCs showed reductions of >80% in anti-sRBC IgG levels. Importantly, mPEG-modified autologous cells did not induce neoantigens or an immune (IgG or IgM) response. These data suggest that the global immunocamouflage of RBCs by polymer grafting may provide a safe and cost-effective means of reducing the risk of alloimmunization.

Complex network structure influences processing in long-term and short-term memory.

PubMed

Vitevitch, Michael S; Chan, Kit Ying; Roodenrys, Steven

2012-07-01

Complex networks describe how entities in systems interact; the structure of such networks is argued to influence processing. One measure of network structure, clustering coefficient, C, measures the extent to which neighbors of a node are also neighbors of each other. Previous psycholinguistic experiments found that the C of phonological word-forms influenced retrieval from the mental lexicon (that portion of long-term memory dedicated to language) during the on-line recognition and production of spoken words. In the present study we examined how network structure influences other retrieval processes in long- and short-term memory. In a false-memory task-examining long-term memory-participants falsely recognized more words with low- than high-C. In a recognition memory task-examining veridical memories in long-term memory-participants correctly recognized more words with low- than high-C. However, participants in a serial recall task-examining redintegration in short-term memory-recalled lists comprised of high-C words more accurately than lists comprised of low-C words. These results demonstrate that network structure influences cognitive processes associated with several forms of memory including lexical, long-term, and short-term.

Contemporary cultural evolution of a conspecific recognition signal following serial translocations.

PubMed

Parker, Kevin A; Hauber, Mark E; Brunton, Dianne H

2010-08-01

The divergence of conspecific recognition signals (CRS) among isolated populations facilitates the evolution of behavioral barriers to gene flow. The influence of CRS evolution on signal effectiveness in isolated populations can be assessed by testing the salience of changes in CRS from surviving ancestral populations but founder events are rarely detected. The population history of the North Island (NI) saddleback Philesturnus rufusater is absolutely known following conservation translocations which increased the number of populations from 1 to 15. With one exception there is no gene flow between these populations. The translocations have generated interisland divergence of male rhythmical song (MRS), a culturally transmitted CRS. We conducted an experimental test of behavioral discrimination in NI saddlebacks exposed to familiar and unfamiliar MRS and found that responses were significantly stronger for familiar MRS, consistent with a model of contemporary cultural evolution leading to discrimination between geographic song variants. Significantly, this result demonstrates the rapid tempo with which discrimination of CRS might evolve within isolated populations and supports both bottleneck and cultural mutation hypotheses in CRS evolution. The evolutionary implications of contemporary cultural evolution in the production and perception of CRS merit debate on the time frames over which conservation management is evaluated.

Adolescents with a diagnosis of anorexia nervosa: parents' experience of recognition and deciding to seek help.

PubMed

Thomson, Samuel; Marriott, Michael; Telford, Katherine; Law, Hou; McLaughlin, Jo; Sayal, Kapil

2014-01-01

Adolescents with anorexia nervosa rarely present themselves as having a problem and are usually reliant on parents to recognise the problem and facilitate help-seeking. This study aimed to investigate parents' experiences of recognising that their child had an eating problem and deciding to seek help. A qualitative study with interpretative phenomenological analysis applied to semi-structured interviews with eight parents of adolescents with a diagnosis of anorexia nervosa. Parents commonly attributed early signs of anorexia nervosa to normal adolescent development and they expected weight loss to be short-lived. As parents' suspicions grew, close monitoring exposing their child's secretive attempts to lose weight and the use of internet searches aided parental recognition of the problem. They avoided using the term anorexia as it made the problem seem 'real'. Following serial unsuccessful attempts to effect change, parental fear for their child's life triggered a desire for professional help. Parents require early advice and support to confirm their suspicions that their child might have anorexia nervosa. Since parents commonly approach the internet for guidance, improving awareness of useful and accurate websites could reduce delays in help-seeking.

Truxene-cored π-expanded triarylborane dyes as single- and two-photon fluorescent probes for fluoride.

PubMed

Yuan, Mao-Sen; Wang, Qi; Wang, Wenji; Wang, Dong-En; Wang, Junru; Wang, Jinyi

2014-03-21

Fluoride anion (F(-)) significantly affects chemical, biological, and environmental processes. Fluoride recognition and detection have received increasing attention. Convenient, effective, and sensitive fluorescent probes for F(-) should urgently be designed and synthesized. In this study, we describe a strategy for constructing two triarylborane-based fluoride fluorescent probes: 2,7,12-tri(2-(5-(dimesitylboryl)thiophen-2-yl)ethynyl)-5,5',10,10',15,15'-hexaethyltruxene (C3B3) with π-3A (acceptor) configuration and 2,7-di(N,N-diphenylamino)-12-(5-(dimesitylboryl)thiophen-2-yl)-5,5',10,10',15,15'-hexaethyltruxene (N2SB) with 2D (donor)-π-A configuration. The loss of color of the tetrahydrofuran solution of these probes from greenish yellow suggests that they can conveniently monitor F(-) at a low concentration (10 μM) free of apparatus. The different structural features of these probes varied their fluorescent responses to F(-). The single-photon fluorescence intensity of C3B3 declined to 90% upon the addition of 4.5 equivalents of F(-) to its tetrahydrofuran solution. However, the single-photon fluorescence intensity of N2SB was enhanced six-fold upon addition of 2.5 equivalents of the F(-). Under the experimental conditions, the detection limits of the two probes for F(-) can reach 12-13 μM (C3B3) and 3-5 μM (N2SB). The ability of the two probes in detecting F(-) in their toluene solutions in the two-photon mode was also investigated. The sensitive two-photon fluorescence responses of both probes make them excellent two-photon fluorescence probes.

Enhancing the response rate of strand displacement-based electrochemical aptamer sensors using bivalent binding aptamer-cDNA probes.

PubMed

Zhang, Ziping; Tao, Cancan; Yin, Jungang; Wang, Yunhui; Li, Yanshen

2018-04-30

Electrochemical aptamer (EA) sensors based on aptamer-cDNA duplex probes (cDNA: complementary DNA) and target induced strand displacement (TISD) recognition are sensitive, selective and capable of detecting a wide variety of target analytes. While substantial research efforts have focused on engineering of new signaling mechanisms for the improvement of sensor sensitivity, little attention was paid to the enhancement of sensor response rate. Typically, the previous TISD based EA sensors exhibited relatively long response times larger than 30min, which mainly resulted from the suboptimal aptamer-cDNA probe structure in which most of aptamer bases were paired to the cDNA bases. In an effort to improve the response rate of this type of sensors, we report here the rational engineering of a quickly responsive and sensitive aptamer-cDNA probe by employing the conception of bivalent interaction in supramolecular chemistry. We design a bivalent cDNA strand through linking two short monovalent cDNA sequences, and it is simultaneously hybridized to two electrode-immobilized aptamer probes to form a bivalent binding (BB) aptamer-cDNA probe. This class of BB probe possesses the advantages of less aptamer bases paired to the cDNA bases for quick response rate and good structural stability for high sensor sensitivity. By use of the rationally designed BB aptamer-cDNA probe, a TISD based EA sensor against ATP with significantly enhanced response rate (with a displacement equilibrium time of 4min) and high sensitivity was successfully constructed. We believe that our BB probe conception will help guide future designs and applications of TISD based EA sensors. Copyright © 2017 Elsevier B.V. All rights reserved.

Facial recognition of happiness among older adults with active and remitted major depression.

PubMed

Shiroma, Paulo R; Thuras, Paul; Johns, Brian; Lim, Kelvin O

2016-09-30

Biased emotion processing in depression might be a trait characteristic independent of mood improvement and a vulnerable factor to develop further depressive episodes. This phenomenon of among older adults with depression has not been adequately examined. In a 2-year cross-sectional study, 59 older patients with either active or remitted major depression, or never-depressed, completed a facial emotion recognition task (FERT) to probe perceptual bias of happiness. The results showed that depressed patients, compared with never depressed subjects, had a significant lower sensitivity to identify happiness particularly at moderate intensity of facial stimuli. Patients in remission from a previous major depressive episode but with none or minimal symptoms had similar sensitivity rate to identify happy facial expressions as compared to patients with an active depressive episode. Further studies would be necessary to confirm whether recognition of happy expression reflects a persistent perceptual bias of major depression in older adults. Published by Elsevier Ireland Ltd.

Recognition of cyclic-di-GMP by a riboswitch conducts translational repression through masking the ribosome-binding site distant from the aptamer domain.

PubMed

Inuzuka, Saki; Kakizawa, Hitoshi; Nishimura, Kei-Ichiro; Naito, Takuto; Miyazaki, Katsushi; Furuta, Hiroyuki; Matsumura, Shigeyoshi; Ikawa, Yoshiya

2018-06-01

The riboswitch is a class of RNA-based gene regulatory machinery that is dependent on recognition of its target ligand by RNA tertiary structures. Ligand recognition is achieved by the aptamer domain, and ligand-dependent structural changes of the expression platform then usually mediate termination of transcription or translational initiation. Ligand-dependent structural changes of the aptamer domain and expression platform have been reported for several riboswitches with short (<40 nucleotides) expression platforms. In this study, we characterized structural changes of the Vc2 c-di-GMP riboswitch that represses translation of downstream open reading frames in a ligand-dependent manner. The Vc2 riboswitch has a long (97 nucleotides) expression platform, but its structure and function are largely unknown. Through mutational analysis and chemical probing, we identified its secondary structures that are possibly responsible for switch-OFF and switch-ON states of translational initiation. © 2018 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

Infrared spectroscopic near-field mapping of single nanotransistors.

PubMed

Huber, A J; Wittborn, J; Hillenbrand, R

2010-06-11

We demonstrate the application of scattering-type scanning near-field optical microscopy (s-SNOM) for infrared (IR) spectroscopic material recognition in state-of-the-art semiconductor devices. In particular, we employ s-SNOM for imaging of industrial CMOS transistors with a resolution better than 20 nm, which allows for the first time IR spectroscopic recognition of amorphous SiO(2) and Si(3)N(4) components in a single transistor device. The experimentally recorded near-field spectral signature of amorphous SiO(2) shows excellent agreement with model calculations based on literature dielectric values, verifying that the characteristic near-field contrasts of SiO(2) stem from a phonon-polariton resonant near-field interaction between the probing tip and the SiO(2) nanostructures. Local material recognition by s-SNOM in combination with its capabilities of contact-free and non-invasive conductivity- and strain-mapping makes IR near-field microscopy a versatile metrology technique for nanoscale material characterization and semiconductor device analysis with application potential in research and development, failure analysis and reverse engineering.

Tunneling readout of hydrogen-bonding based recognition

PubMed Central

Chang, Shuai; He, Jin; Kibel, Ashley; Lee, Myeong; Sankey, Otto; Zhang, Peiming; Lindsay, Stuart

2009-01-01

Hydrogen bonding has a ubiquitous role in electron transport1,2 and in molecular recognition, with DNA base-pairing being the best known example.3 Scanning tunneling microscope (STM) images4 and measurements of the decay of tunnel-current as a molecular junction is pulled apart by the STM tip, 5 are sensitive to hydrogen-bonded interactions. Here we show that these tunnel-decay signals can be used to measure the strength of hydrogen bonding in DNA basepairs. Junctions that are held together by three hydrogen bonds per basepair (e.g., guanine-cytosine interactions) are stiffer than junctions held together by two hydrogen bonds per basepair (e.g., adenine-thymine interactions). Similar, but less-pronounced, effects are observed on the approach of the tunneling probe, implying that hydrogen-bond dependent attractive forces also have a role in determining the rise of current. These effects provide new mechanisms for making sensors that transduce a molecular recognition event into an electronic signal. PMID:19421214

Electrospun Nanofibers from a Tricyanofuran-Based Molecular Switch for Colorimetric Recognition of Ammonia Gas.

PubMed

Khattab, Tawfik A; Abdelmoez, Sherif; Klapötke, Thomas M

2016-03-14

A chromophore based on tricyanofuran (TCF) with a hydrazone (H) recognition moiety was developed. Its molecular-switching performance is reversible and has differential sensitivity towards aqueous ammonia at comparable concentrations. Nanofibers were fabricated from the TCF-H chromophore by electrospinning. The film fabricated from these nanofibers functions as a solid-state optical chemosensor for probing ammonia vapor. Recognition of ammonia vapor occurs by proton transfer from the hydrazone fragment of the chromophore to the ammonia nitrogen atom and is facilitated by the strongly electron withdrawing TCF fragment. The TCF-H chromophore was added to a solution of poly(acrylic acid), which was electrospun to obtain a nanofibrous sensor device. The morphology of the nanofibrous sensor was determined by SEM, which showed that nanofibers with a diameter range of 200-450 nm formed a nonwoven mat. The resultant nanofibrous sensor showed very good sensitivity in ammonia-vapor detection. Furthermore, very good reversibility and short response time were also observed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Action Recognition and Movement Direction Discrimination Tasks Are Associated with Different Adaptation Patterns

PubMed Central

de la Rosa, Stephan; Ekramnia, Mina; Bülthoff, Heinrich H.

2016-01-01

The ability to discriminate between different actions is essential for action recognition and social interactions. Surprisingly previous research has often probed action recognition mechanisms with tasks that did not require participants to discriminate between actions, e.g., left-right direction discrimination tasks. It is not known to what degree visual processes in direction discrimination tasks are also involved in the discrimination of actions, e.g., when telling apart a handshake from a high-five. Here, we examined whether action discrimination is influenced by movement direction and whether direction discrimination depends on the type of action. We used an action adaptation paradigm to target action and direction discrimination specific visual processes. In separate conditions participants visually adapted to forward and backward moving handshake and high-five actions. Participants subsequently categorized either the action or the movement direction of an ambiguous action. The results showed that direction discrimination adaptation effects were modulated by the type of action but action discrimination adaptation effects were unaffected by movement direction. These results suggest that action discrimination and direction categorization rely on partly different visual information. We propose that action discrimination tasks should be considered for the exploration of visual action recognition mechanisms. PMID:26941633

Perspective: Watching low-frequency vibrations of water in biomolecular recognition by THz spectroscopy.

PubMed

Xu, Yao; Havenith, Martina

2015-11-07

Terahertz (THz) spectroscopy has turned out to be a powerful tool which is able to shed new light on the role of water in biomolecular processes. The low frequency spectrum of the solvated biomolecule in combination with MD simulations provides deep insights into the collective hydrogen bond dynamics on the sub-ps time scale. The absorption spectrum between 1 THz and 10 THz of solvated biomolecules is sensitive to changes in the fast fluctuations of the water network. Systematic studies on mutants of antifreeze proteins indicate a direct correlation between biological activity and a retardation of the (sub)-ps hydration dynamics at the protein binding site, i.e., a "hydration funnel." Kinetic THz absorption studies probe the temporal changes of THz absorption during a biological process, and give access to the kinetics of the coupled protein-hydration dynamics. When combined with simulations, the observed results can be explained in terms of a two-tier model involving a local binding and a long range influence on the hydration bond dynamics of the water around the binding site that highlights the significance of the changes in the hydration dynamics at recognition site for biomolecular recognition. Water is shown to assist molecular recognition processes.

Perspective: Watching low-frequency vibrations of water in biomolecular recognition by THz spectroscopy

NASA Astrophysics Data System (ADS)

Xu, Yao; Havenith, Martina

2015-11-01

Terahertz (THz) spectroscopy has turned out to be a powerful tool which is able to shed new light on the role of water in biomolecular processes. The low frequency spectrum of the solvated biomolecule in combination with MD simulations provides deep insights into the collective hydrogen bond dynamics on the sub-ps time scale. The absorption spectrum between 1 THz and 10 THz of solvated biomolecules is sensitive to changes in the fast fluctuations of the water network. Systematic studies on mutants of antifreeze proteins indicate a direct correlation between biological activity and a retardation of the (sub)-ps hydration dynamics at the protein binding site, i.e., a "hydration funnel." Kinetic THz absorption studies probe the temporal changes of THz absorption during a biological process, and give access to the kinetics of the coupled protein-hydration dynamics. When combined with simulations, the observed results can be explained in terms of a two-tier model involving a local binding and a long range influence on the hydration bond dynamics of the water around the binding site that highlights the significance of the changes in the hydration dynamics at recognition site for biomolecular recognition. Water is shown to assist molecular recognition processes.

MMP-13 In-Vivo Molecular Imaging Reveals Early Expression in Lung Adenocarcinoma

PubMed Central

Salaün, Mathieu; Peng, Jing; Hensley, Harvey H.; Roder, Navid; Flieder, Douglas B.; Houlle-Crépin, Solène; Abramovici-Roels, Olivia; Sabourin, Jean-Christophe; Thiberville, Luc; Clapper, Margie L.

2015-01-01

Introduction Several matrix metalloproteinases (MMPs) are overexpressed in lung cancer and may serve as potential targets for the development of bioactivable probes for molecular imaging. Objective To characterize and monitor the activity of MMPs during the progression of lung adenocarcinoma. Methods K-rasLSL-G12D mice were imaged serially during the development of adenocarcinomas using fluorescence molecular tomography (FMT) and a probe specific for MMP-2, -3, -9 and -13. Lung tumors were identified using FMT and MRI co-registration, and the probe concentration in each tumor was assessed at each time-point. The expression of Mmp2, -3, -9, -13 was quantified by qRT-PCR using RNA isolated from microdissected tumor cells. Immunohistochemical staining of overexpressed MMPs in animals was assessed on human lung tumors. Results In mice, 7 adenomas and 5 adenocarcinomas showed an increase in fluorescent signal on successive FMT scans, starting between weeks 4 and 8. qRT-PCR assays revealed significant overexpression of only Mmp-13 in mice lung tumors. In human tumors, a high MMP-13 immunostaining index was found in tumor cells from invasive lesions (24/27), but in none of the non-invasive (0/4) (p=0.001). Conclusion MMP-13 is detected in early pulmonary invasive adenocarcinomas and may be a potential target for molecular imaging of lung cancer. PMID:26193700

β-Cyclodextrin functionalised gold nanoclusters as luminescence probes for the ultrasensitive detection of dopamine.

PubMed

Ban, Rui; Abdel-Halim, E S; Zhang, Jianrong; Zhu, Jun-Jie

2015-02-21

A novel luminescence probe based on mono-6-amino-β-cyclodextrin (NH2-β-CD) functionalised gold nanoclusters (β-CD-AuNC) was designed for dopamine (DA) detection. The NH2-β-CD molecules were conjugated onto the surface of 11-mercaptoundecanoic acid capped AuNCs (11-MUA-AuNC) via a carbodiimide coupling reaction. The integrity of the β-CD cavities was preserved on the surface of AuNCs and they retained their capability for molecular DA host-guest recognition. DA could be captured by the β-CD cavities to form an inclusion complex in which the oxidised DA could quench the fluorescence of the β-CD-AuNC probe by electron transfer. The probe could be used to quantify DA in the range of 5-1000 nM with a detection limit of 2 nM. This sensitivity was 1-2 orders of magnitude higher than that in previously reported methods. Interference by both ascorbic acid (AA) and uric acid (UA) was not observed. Therefore, the β-CD-AuNC probe could be directly used to determine the DA content in biological samples without further separation. This strategy was successfully applied to a DA assay in spiked human serum samples and it exhibited remarkable accuracy, sensitivity and selectivity.

A Single Electrochemical Probe Used for Analysis of Multiple Nucleic Acid Sequences

PubMed Central

Mills, Dawn M.; Calvo-Marzal, Percy; Pinzon, Jeffer M.; Armas, Stephanie; Kolpashchikov, Dmitry M.; Chumbimuni-Torres, Karin Y.

2017-01-01

Electrochemical hybridization sensors have been explored extensively for analysis of specific nucleic acids. However, commercialization of the platform is hindered by the need for attachment of separate oligonucleotide probes complementary to a RNA or DNA target to an electrode’s surface. Here we demonstrate that a single probe can be used to analyze several nucleic acid targets with high selectivity and low cost. The universal electrochemical four-way junction (4J)-forming (UE4J) sensor consists of a universal DNA stem-loop (USL) probe attached to the electrode’s surface and two adaptor strands (m and f) which hybridize to the USL probe and the analyte to form a 4J associate. The m adaptor strand was conjugated with a methylene blue redox marker for signal ON sensing and monitored using square wave voltammetry. We demonstrated that a single sensor can be used for detection of several different DNA/RNA sequences and can be regenerated in 30 seconds by a simple water rinse. The UE4J sensor enables a high selectivity by recognition of a single base substitution, even at room temperature. The UE4J sensor opens a venue for a re-useable universal platform that can be adopted at low cost for the analysis of DNA or RNA targets. PMID:29371782

Recombinant phage probes for Listeria monocytogenes

NASA Astrophysics Data System (ADS)

Carnazza, S.; Gioffrè, G.; Felici, F.; Guglielmino, S.

2007-10-01

Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 104 cells ml-1. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products.

Tandem Payne/Dakin Reaction: A New Strategy for Hydrogen Peroxide Detection and Molecular Imaging.

PubMed

Yang, Dan; Ye, Sen; Hu, Jun Jacob

2018-06-22

Hydrogen peroxide (H2O2) has been recognized as one of the most significant ROS (reactive oxygen species) in human health and disease. Due to the intrinsic attributes of H2O2 such as low reactivity under physiological pH, it is exceedingly challenging to develop small molecule fluorescent probes with high selectivity and sensitivity to visualize H2O2 in intricate biological milieux. To address this gap, we report a rationally designed tandem Payne/Dakin reaction that is specific to molecular recognition of H2O2, and demonstrate its application in developing novel biocompatible fluorescent probes. New H2O2 probes based on this unique chemical strategy can be facilely synthesized by a general coupling reaction, and the practical applicability of those probes has been confirmed by the visualization of endogenously produced H2O2 in living cells. In particular, starvation induced H2O2 production in mouse macrophages has been detected by our novel probe in both confocal imaging and flow cytometry. This tandem Payne/Dakin reaction provides a basis for developing more sophisticated molecular tools to interrogate H2O2 functions in biological phenomena. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hairpin DNA probe with 5'-TCC/CCC-3' overhangs for the creation of silver nanoclusters and miRNA assay.

PubMed

Xia, Xiaodong; Hao, Yuanqiang; Hu, Shengqiang; Wang, Jianxiu

2014-01-15

A facile strategy for the assay of target miRNA using fluorescent silver nanoclusters (AgNCs) has been described. Due to the preferable interaction between cytosine residues and Ag(+), a short cytosine-rich oligonucleotide (ODN) with only six bases 5'-TCCCCC-3' served as an efficient scaffold for the creation of the AgNCs. The AgNCs displayed a bright red emission when excited at 545nm. Such ODN base-stabilized AgNCs have been exploited for miRNA sensing. Overhangs of TCC at the 5' end (5'-TCC) and CCC at the 3' end (CCC-3') (denoted as 5'-TCC/CCC-3') appended to the hairpin ODN probe which also contains recognition sequences for target miRNA were included. Interestingly, the AgNCs/hairpin ODN probe showed similar spectral properties as that templated by 5'-TCCCCC-3'. The formation of the hairpin ODN probe/miRNA duplex separated the 5'-TCC/CCC-3' overhangs, thus disturbing the optical property or structure of the AgNCs. As a result, fluorescence quenching of the AgNCs/hairpin ODN probe was obtained, which allows for facile determination of target miRNA. The proposed method is simple and cost-effective, holding great promise for clinical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Generality of a congruity effect in judgements of relative order.

PubMed

Liu, Yang S; Chan, Michelle; Caplan, Jeremy B

2014-10-01

The judgement of relative order (JOR) procedure is used to investigate serial-order memory. Measuring response times, the wording of the instructions (whether the earlier or the later item was designated as the target) reversed the direction of search in subspan lists (Chan, Ross, Earle, & Caplan Psychonomic Bulletin & Review, 16(5), 945-951, 2009). If a similar congruity effect applied to above-span lists and, furthermore, with error rate as the measure, this could suggest how to model order memory across scales. Participants performed JORs on lists of nouns (Experiment 1: list lengths = 4, 6, 8, 10) or consonants (Experiment 2: list lengths = 4, 8). In addition to the usual distance, primacy, and recency effects, instructions interacted with serial position of the later probe in both experiments, not only in response time, but also in error rate, suggesting that availability, not just accessibility, is affected by instructions. The congruity effect challenges current memory models. We fitted Hacker's (Journal of Experimental Psychology: Human Learning and Memory, 6(6), 651-675, 1980) self-terminating search model to our data and found that a switch in search direction could explain the congruity effect for short lists, but not longer lists. This suggests that JORs may need to be understood via direct-access models, adapted to produce a congruity effect, or a mix of mechanisms.

Re-examination of the role of the human acoustic stapedius reflex

NASA Astrophysics Data System (ADS)

Phillips, Dennis P.; Stuart, Andrew; Carpenter, Michael

2002-05-01

The ``rollover'' seen in the word recognition performance scores of patients with Bell's palsy (facial nerve paralysis) has historically been taken as an indicator of the role of the stapedius reflex in the protection from upward spread of masking. Bell's palsy, however, may be a polyneuropathy, so it is not clear that the poor word recognition performance at high levels is necessarily attributable specifically to impaired facial nerve function. The present article reports two new experiments that probe whether an isolated impairment of the stapedius reflex can produce rollover in word recognition performance-intensity functions. In experiment 1, performance-intensity functions for monosyllabic speech materials were obtained from ten normal listeners under two listening conditions: normal and low-frequency augmented to offset the effects of the stapedius reflex on the transmission of low-frequency vibrations to the cochlea. There was no effect of the spectral augmentation on word recognition for stimulus levels up to 107 dB SPL. In experiment 2, six patients who had undergone stapedectomy were tested for rollover using performance-intensity functions. None of the patients showed rollover in their performance-intensity functions, even at stimulus levels in excess of 100 dB HL. These data suggest that if the stapedius reflex has a role in protection from upward spread of masking, then this role is inconsequential for word recognition in quiet.

Holistic processing, contact, and the other-race effect in face recognition.

PubMed

Zhao, Mintao; Hayward, William G; Bülthoff, Isabelle

2014-12-01

Face recognition, holistic processing, and processing of configural and featural facial information are known to be influenced by face race, with better performance for own- than other-race faces. However, whether these various other-race effects (OREs) arise from the same underlying mechanisms or from different processes remains unclear. The present study addressed this question by measuring the OREs in a set of face recognition tasks, and testing whether these OREs are correlated with each other. Participants performed different tasks probing (1) face recognition, (2) holistic processing, (3) processing of configural information, and (4) processing of featural information for both own- and other-race faces. Their contact with other-race people was also assessed with a questionnaire. The results show significant OREs in tasks testing face memory and processing of configural information, but not in tasks testing either holistic processing or processing of featural information. Importantly, there was no cross-task correlation between any of the measured OREs. Moreover, the level of other-race contact predicted only the OREs obtained in tasks testing face memory and processing of configural information. These results indicate that these various cross-race differences originate from different aspects of face processing, in contrary to the view that the ORE in face recognition is due to cross-race differences in terms of holistic processing. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Quantitative SERS Detection of Dopamine in Cerebrospinal Fluid by Dual-Recognition-Induced Hot Spot Generation.

PubMed

Zhang, Kun; Liu, Yu; Wang, Yuning; Zhang, Ren; Liu, Jiangang; Wei, Jia; Qian, Hufei; Qian, Kun; Chen, Ruoping; Liu, Baohong

2018-05-09

Reliable profiling of the extracellular dopamine (DA) concentration in the central nervous system is essential for a deep understanding of its biological and pathological functions. However, quantitative determination of this neurotransmitter remains a challenge because of the extremely low concentration of DA in the cerebrospinal fluid (CSF) of patients. Herein, on the basis of the specific recognition of boronate toward diol and N-hydroxysuccinimide ester toward the amine group, a simple and highly sensitive strategy was presented for DA detection by using surface-enhanced Raman scattering (SERS) spectroscopy as a signal readout. This was realized by first immobilizing 3,3'-dithiodipropionic acid di( N-hydroxysuccinimide ester) on gold thin film surfaces to capture DA, followed by introducing 3-mercaptophenylboronic acid (3-MPBA)-functionalized silver nanoparticles to generate numerous plasmonic "hot spots" with the nanoparticle-on-mirror geometry. Such a dual-recognition mechanism not only avoids complicated bioelement-based manipulations but also efficiently decreases the background signal. With the direct use of the recognition probe 3-MPBA as a Raman reporter, the "signal-on" SERS method was employed to quantify the concentration of DA from 1 pM to 1 μM with a detection limit of 0.3 pM. Moreover, our dual-recognition-directed SERS assay exhibited a high resistance to cerebral interference and was successfully applied to monitoring of DA in CSF samples of patients.

A Unitary Anesthetic Binding Site at High Resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vedula, L. Sangeetha; Brannigan, Grace; Economou, Nicoleta J.

2009-10-21

Propofol is the most widely used injectable general anesthetic. Its targets include ligand-gated ion channels such as the GABA{sub A} receptor, but such receptor-channel complexes remain challenging to study at atomic resolution. Until structural biology methods advance to the point of being able to deal with systems such as the GABA{sub A} receptor, it will be necessary to use more tractable surrogates to probe the molecular details of anesthetic recognition. We have previously shown that recognition of inhalational general anesthetics by the model protein apoferritin closely mirrors recognition by more complex and clinically relevant protein targets; here we show thatmore » apoferritin also binds propofol and related GABAergic anesthetics, and that the same binding site mediates recognition of both inhalational and injectable anesthetics. Apoferritin binding affinities for a series of propofol analogs were found to be strongly correlated with the ability to potentiate GABA responses at GABA{sub A} receptors, validating this model system for injectable anesthetics. High resolution x-ray crystal structures reveal that, despite the presence of hydrogen bond donors and acceptors, anesthetic recognition is mediated largely by van der Waals forces and the hydrophobic effect. Molecular dynamics simulations indicate that the ligands undergo considerable fluctuations about their equilibrium positions. Finally, apoferritin displays both structural and dynamic responses to anesthetic binding, which may mimic changes elicited by anesthetics in physiologic targets like ion channels.« less

A Unitary Anesthetic Binding Site at High Resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

L Vedula; G Brannigan; N Economou

2011-12-31

Propofol is the most widely used injectable general anesthetic. Its targets include ligand-gated ion channels such as the GABA{sub A} receptor, but such receptor-channel complexes remain challenging to study at atomic resolution. Until structural biology methods advance to the point of being able to deal with systems such as the GABA{sub A} receptor, it will be necessary to use more tractable surrogates to probe the molecular details of anesthetic recognition. We have previously shown that recognition of inhalational general anesthetics by the model protein apoferritin closely mirrors recognition by more complex and clinically relevant protein targets; here we show thatmore » apoferritin also binds propofol and related GABAergic anesthetics, and that the same binding site mediates recognition of both inhalational and injectable anesthetics. Apoferritin binding affinities for a series of propofol analogs were found to be strongly correlated with the ability to potentiate GABA responses at GABA{sub A} receptors, validating this model system for injectable anesthetics. High resolution x-ray crystal structures reveal that, despite the presence of hydrogen bond donors and acceptors, anesthetic recognition is mediated largely by van der Waals forces and the hydrophobic effect. Molecular dynamics simulations indicate that the ligands undergo considerable fluctuations about their equilibrium positions. Finally, apoferritin displays both structural and dynamic responses to anesthetic binding, which may mimic changes elicited by anesthetics in physiologic targets like ion channels.« less

A Unitary Anesthetic-Binding Site at High Resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vedula, L.; Brannigan, G; Economou, N

2009-01-01

Propofol is the most widely used injectable general anesthetic. Its targets include ligand-gated ion channels such as the GABAA receptor, but such receptor-channel complexes remain challenging to study at atomic resolution. Until structural biology methods advance to the point of being able to deal with systems such as the GABA{sub A} receptor, it will be necessary to use more tractable surrogates to probe the molecular details of anesthetic recognition. We have previously shown that recognition of inhalational general anesthetics by the model protein apoferritin closely mirrors recognition by more complex and clinically relevant protein targets; here we show that apoferritinmore » also binds propofol and related GABAergic anesthetics, and that the same binding site mediates recognition of both inhalational and injectable anesthetics. Apoferritin binding affinities for a series of propofol analogs were found to be strongly correlated with the ability to potentiate GABA responses at GABA{sub A} receptors, validating this model system for injectable anesthetics. High resolution x-ray crystal structures reveal that, despite the presence of hydrogen bond donors and acceptors, anesthetic recognition is mediated largely by van der Waals forces and the hydrophobic effect. Molecular dynamics simulations indicate that the ligands undergo considerable fluctuations about their equilibrium positions. Finally, apoferritin displays both structural and dynamic responses to anesthetic binding, which may mimic changes elicited by anesthetics in physiologic targets like ion channels.« less

Variability sensitivity of dynamic texture based recognition in clinical CT data

NASA Astrophysics Data System (ADS)

Kwitt, Roland; Razzaque, Sharif; Lowell, Jeffrey; Aylward, Stephen

2014-03-01

Dynamic texture recognition using a database of template models has recently shown promising results for the task of localizing anatomical structures in Ultrasound video. In order to understand its clinical value, it is imperative to study the sensitivity with respect to inter-patient variability as well as sensitivity to acquisition parameters such as Ultrasound probe angle. Fully addressing patient and acquisition variability issues, however, would require a large database of clinical Ultrasound from many patients, acquired in a multitude of controlled conditions, e.g., using a tracked transducer. Since such data is not readily attainable, we advocate an alternative evaluation strategy using abdominal CT data as a surrogate. In this paper, we describe how to replicate Ultrasound variabilities by extracting subvolumes from CT and interpreting the image material as an ordered sequence of video frames. Utilizing this technique, and based on a database of abdominal CT from 45 patients, we report recognition results on an organ (kidney) recognition task, where we try to discriminate kidney subvolumes/videos from a collection of randomly sampled negative instances. We demonstrate that (1) dynamic texture recognition is relatively insensitive to inter-patient variation while (2) viewing angle variability needs to be accounted for in the template database. Since naively extending the template database to counteract variability issues can lead to impractical database sizes, we propose an alternative strategy based on automated identification of a small set of representative models.

3D face recognition based on multiple keypoint descriptors and sparse representation.

PubMed

Zhang, Lin; Ding, Zhixuan; Li, Hongyu; Shen, Ying; Lu, Jianwei

2014-01-01

Recent years have witnessed a growing interest in developing methods for 3D face recognition. However, 3D scans often suffer from the problems of missing parts, large facial expressions, and occlusions. To be useful in real-world applications, a 3D face recognition approach should be able to handle these challenges. In this paper, we propose a novel general approach to deal with the 3D face recognition problem by making use of multiple keypoint descriptors (MKD) and the sparse representation-based classification (SRC). We call the proposed method 3DMKDSRC for short. Specifically, with 3DMKDSRC, each 3D face scan is represented as a set of descriptor vectors extracted from keypoints by meshSIFT. Descriptor vectors of gallery samples form the gallery dictionary. Given a probe 3D face scan, its descriptors are extracted at first and then its identity can be determined by using a multitask SRC. The proposed 3DMKDSRC approach does not require the pre-alignment between two face scans and is quite robust to the problems of missing data, occlusions and expressions. Its superiority over the other leading 3D face recognition schemes has been corroborated by extensive experiments conducted on three benchmark databases, Bosphorus, GavabDB, and FRGC2.0. The Matlab source code for 3DMKDSRC and the related evaluation results are publicly available at http://sse.tongji.edu.cn/linzhang/3dmkdsrcface/3dmkdsrc.htm.

Child–Adult Differences in Using Dual-Task Paradigms to Measure Listening Effort

PubMed Central

Charles, Lauren M.; Ricketts, Todd A.

2017-01-01

Purpose The purpose of the project was to investigate the effects modifying the secondary task in a dual-task paradigm to measure objective listening effort. To be specific, the complexity and depth of processing were increased relative to a simple secondary task. Method Three dual-task paradigms were developed for school-age children. The primary task was word recognition. The secondary task was a physical response to a visual probe (simple task), a physical response to a complex probe (increased complexity), or word categorization (increased depth of processing). Sixteen adults (22–32 years, M = 25.4) and 22 children (9–17 years, M = 13.2) were tested using the 3 paradigms in quiet and noise. Results For both groups, manipulations of the secondary task did not affect word recognition performance. For adults, increasing depth of processing increased the calculated effect of noise; however, for children, results with the deep secondary task were the least stable. Conclusions Manipulations of the secondary task differentially affected adults and children. Consistent with previous findings, increased depth of processing enhanced paradigm sensitivity for adults. However, younger participants were more likely to demonstrate the expected effects of noise on listening effort using a secondary task that did not require deep processing. PMID:28346816

Monkeys show recognition without priming in a classification task.

PubMed

Basile, Benjamin M; Hampton, Robert R

2013-02-01

Humans show visual perceptual priming by identifying degraded images faster and more accurately if they have seen the original images, while simultaneously failing to recognize the same images. Such priming is commonly thought, with little evidence, to be widely distributed phylogenetically. Following Brodbeck (1997), we trained rhesus monkeys (Macaca mulatta) to categorize photographs according to content (e.g., birds, fish, flowers, people). In probe trials, we tested whether monkeys were faster or more accurate at categorizing degraded versions of previously seen images (primed) than degraded versions of novel images (unprimed). Monkeys categorized reliably, but showed no benefit from having previously seen the images. This finding was robust across manipulations of image quality (color, grayscale, line drawings), type of image degradation (occlusion, blurring), levels of processing, and number of repetitions of the prime. By contrast, in probe matching-to-sample trials, monkeys recognized the primes, demonstrating that they remembered the primes and could discriminate them from other images in the same category under the conditions used to test for priming. Two experiments that replicated Brodbeck's (1997) procedures also produced no evidence of priming. This inability to find priming in monkeys under perceptual conditions sufficient for recognition presents a puzzle. Copyright © 2012 Elsevier B.V. All rights reserved.

SRB-2: a promiscuous rainbow aptamer for live-cell RNA imaging.

PubMed

Sunbul, Murat; Jäschke, Andres

2018-06-21

The SRB-2 aptamer originally selected against sulforhodamine B is shown here to promiscuously bind to various dyes with different colors. Binding of SRB-2 to these dyes results in either fluorescence increase or decrease, making them attractive for fluorescence microscopy and biological assays. By systematically varying fluorophore structural elements and measuring dissociation constants, the principles of fluorophore recognition by SRB-2 were analyzed. The obtained structure-activity relationships allowed us to rationally design a novel, bright, orange fluorescent turn-on probe (TMR-DN) with low background fluorescence, enabling no-wash live-cell RNA imaging. This new probe improved the signal-to-background ratio of fluorescence images by one order of magnitude over best previously known probe for this aptamer. The utility of TMR-DN is demonstrated by imaging ribosomal and messenger RNAs, allowing the observation of distinct localization patterns in bacteria and mammalian cells. The SRB-2 / TMR-DN system is found to be orthogonal to the Spinach/DFHBI and MG/Malachite green aptamer/dye systems.

Electrochemical detection of aqueous Ag+ based on Ag+-assisted ligation reaction

NASA Astrophysics Data System (ADS)

Miao, Peng; Han, Kun; Wang, Bidou; Luo, Gangyin; Wang, Peng; Chen, Mingli; Tang, Yuguo

2015-03-01

In this work, a novel strategy to fabricate a highly sensitive and selective biosensor for the detection of Ag+ is proposed. Two DNA probes are designed and modified on a gold electrode surface by gold-sulfur chemistry and hybridization. In the presence of Ag+, cytosine-Ag+-cytosine composite forms and facilitates the ligation event on the electrode surface, which can block the release of electrochemical signals labeled on one of the two DNA probes during denaturation process. Ag+ can be sensitively detected with the detection limit of 0.1 nM, which is much lower than the toxicity level defined by U.S. Environmental Protection Agency. This biosensor can easily distinguish Ag+ from other interfering ions and the performances in real water samples are also satisfactory. Moreover, the two DNA probes are designed to contain the recognition sequences of a nicking endonuclease, and the ligated DNA can thus be cleaved at the original site. Therefore, the electrode can be regenerated, which allows the biosensor to be reused for additional tests.

Identifying the preferred RNA motifs and chemotypes that interact by probing millions of combinations.

PubMed

Tran, Tuan; Disney, Matthew D

2012-01-01

RNA is an important therapeutic target but information about RNA-ligand interactions is limited. Here, we report a screening method that probes over 3,000,000 combinations of RNA motif-small molecule interactions to identify the privileged RNA structures and chemical spaces that interact. Specifically, a small molecule library biased for binding RNA was probed for binding to over 70,000 unique RNA motifs in a high throughput solution-based screen. The RNA motifs that specifically bind each small molecule were identified by microarray-based selection. In this library-versus-library or multidimensional combinatorial screening approach, hairpin loops (among a variety of RNA motifs) were the preferred RNA motif space that binds small molecules. Furthermore, it was shown that indole, 2-phenyl indole, 2-phenyl benzimidazole and pyridinium chemotypes allow for specific recognition of RNA motifs. As targeting RNA with small molecules is an extremely challenging area, these studies provide new information on RNA-ligand interactions that has many potential uses.

Identifying the Preferred RNA Motifs and Chemotypes that Interact by Probing Millions of Combinations

PubMed Central

Tran, Tuan; Disney, Matthew D.

2012-01-01

RNA is an important therapeutic target but information about RNA-ligand interactions is limited. Here we report a screening method that probes over 3,000,000 combinations of RNA motif-small molecule interactions to identify the privileged RNA structures and chemical spaces that interact. Specifically, a small molecule library biased for binding RNA was probed for binding to over 70,000 unique RNA motifs in a high throughput solution-based screen. The RNA motifs that specifically bind each small molecule were identified by microarray-based selection. In this library-versus-library or multidimensional combinatorial screening approach, hairpin loops (amongst a variety of RNA motifs) were the preferred RNA motif space that binds small molecules. Furthermore, it was shown that indole, 2-phenyl indole, 2-phenyl benzimidazole, and pyridinium chemotypes allow for specific recognition of RNA motifs. Since targeting RNA with small molecules is an extremely challenging area, these studies provide new information on RNA-ligand interactions that has many potential uses. PMID:23047683

Situation Model Updating in Young and Older Adults: Global versus Incremental Mechanisms

PubMed Central

Bailey, Heather R.; Zacks, Jeffrey M.

2015-01-01

Readers construct mental models of situations described by text. Activity in narrative text is dynamic, so readers must frequently update their situation models when dimensions of the situation change. Updating can be incremental, such that a change leads to updating just the dimension that changed, or global, such that the entire model is updated. Here, we asked whether older and young adults make differential use of incremental and global updating. Participants read narratives containing changes in characters and spatial location and responded to recognition probes throughout the texts. Responses were slower when probes followed a change, suggesting that situation models were updated at changes. When either dimension changed, responses to probes for both dimensions were slowed; this provides evidence for global updating. Moreover, older adults showed stronger evidence of global updating than did young adults. One possibility is that older adults perform more global updating to offset reduced ability to manipulate information in working memory. PMID:25938248

A chromogenic and fluorogenic rhodol-based chemosensor for hydrazine detection and its application in live cell bioimaging

NASA Astrophysics Data System (ADS)

Tiensomjitr, Khomsan; Noorat, Rattha; Chomngam, Sinchai; Wechakorn, Kanokorn; Prabpai, Samran; Kanjanasirirat, Phongthon; Pewkliang, Yongyut; Borwornpinyo, Suparerk; Kongsaeree, Palangpon

2018-04-01

A rhodol-based fluorescent probe has been developed as a selective hydrazine chemosensor using levulinate as a recognition site. The rhodol levulinate probe (RL) demonstrated high selectivity and sensitivity toward hydrazine among other molecules. The chromogenic response of RL solution to hydrazine from colorless to pink could be readily observed by the naked eye, while strong fluorescence emission could be monitored upon excitation at 525 nm. The detection process occurred via a ring-opening process of the spirolactone initiated by hydrazinolysis, triggering the fluorescence emission with a 53-fold enhancement. The probe rapidly reacted with hydrazine in aqueous medium with the detection limit of 26 nM (0.83 ppb), lower than the threshold limit value (TLV) of 10 ppb suggested by the U.S. Environmental Protection Agency. Furthermore, RL-impregnated paper strips could detect hydrazine vapor. For biological applicability of RL, its membrane-permeable property led to bioimaging of hydrazine in live HepG2 cells by confocal fluorescence microscopy.

Influx of extracellular Zn(2+) into the hippocampal CA1 neurons is required for cognitive performance via long-term potentiation.

PubMed

Takeda, A; Suzuki, M; Tempaku, M; Ohashi, K; Tamano, H

2015-09-24

Physiological significance of synaptic Zn(2+) signaling was examined in the CA1 of young rats. In vivo CA1 long-term potentiation (LTP) was induced using a recording electrode attached to a microdialysis probe and the recording region was locally perfused with artificial cerebrospinal fluid (ACSF) via the microdialysis probe. In vivo CA1 LTP was inhibited under perfusion with CaEDTA and ZnAF-2DA, extracellular and intracellular Zn(2+) chelators, respectively, suggesting that the influx of extracellular Zn(2+) is required for in vivo CA1 LTP induction. The increase in intracellular Zn(2+) was chelated with intracellular ZnAF-2 in the CA1 1h after local injection of ZnAF-2DA into the CA1, suggesting that intracellular Zn(2+) signaling induced during learning is blocked with intracellular ZnAF-2 when the learning was performed 1h after ZnAF-2DA injection. Object recognition was affected when training of object recognition test was performed 1h after ZnAF-2DA injection. These data suggest that intracellular Zn(2+) signaling in the CA1 is required for object recognition memory via LTP. Surprisingly, in vivo CA1 LTP was affected under perfusion with 0.1-1μM ZnCl2, unlike the previous data that in vitro CA1 LTP was enhanced in the presence of 1-5μM ZnCl2. The influx of extracellular Zn(2+) into CA1 pyramidal cells has bidirectional action in CA1 LTP. The present study indicates that the degree of extracellular Zn(2+) influx into CA1 neurons is critical for LTP and cognitive performance. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Targeting RNA in mammalian systems with small molecules.

PubMed

Donlic, Anita; Hargrove, Amanda E

2018-05-03

The recognition of RNA functions beyond canonical protein synthesis has challenged the central dogma of molecular biology. Indeed, RNA is now known to directly regulate many important cellular processes, including transcription, splicing, translation, and epigenetic modifications. The misregulation of these processes in disease has led to an appreciation of RNA as a therapeutic target. This potential was first recognized in bacteria and viruses, but discoveries of new RNA classes following the sequencing of the human genome have invigorated exploration of its disease-related functions in mammals. As stable structure formation is evolving as a hallmark of mammalian RNAs, the prospect of utilizing small molecules to specifically probe the function of RNA structural domains and their interactions is gaining increased recognition. To date, researchers have discovered bioactive small molecules that modulate phenotypes by binding to expanded repeats, microRNAs, G-quadruplex structures, and RNA splice sites in neurological disorders, cancers, and other diseases. The lessons learned from achieving these successes both call for additional studies and encourage exploration of the plethora of mammalian RNAs whose precise mechanisms of action remain to be elucidated. Efforts toward understanding fundamental principles of small molecule-RNA recognition combined with advances in methodology development should pave the way toward targeting emerging RNA classes such as long noncoding RNAs. Together, these endeavors can unlock the full potential of small molecule-based probing of RNA-regulated processes and enable us to discover new biology and underexplored avenues for therapeutic intervention in human disease. This article is categorized under: RNA Methods > RNA Analyses In Vitro and In Silico RNA Interactions with Proteins and Other Molecules > Small Molecule-RNA Interactions RNA in Disease and Development > RNA in Disease. © 2018 Wiley Periodicals, Inc.

Enlightening mineral iron sensing in Pseudomonas fluorescens by surface active maghemite nanoparticles: Involvement of the OprF porin.

PubMed

Magro, Massimiliano; Fasolato, Luca; Bonaiuto, Emanuela; Andreani, Nadia Andrea; Baratella, Davide; Corraducci, Vittorino; Miotto, Giovanni; Cardazzo, Barbara; Vianello, Fabio

2016-10-01

Mineral iron(III) recognition by bacteria is considered a matter of debate. The peculiar surface chemistry of novel naked magnetic nanoparticles, called SAMNs (surface active maghemite nanoparticles) characterized by solvent exposed Fe(3+) sites on their surface, was exploited for studying mineral iron sensing in Pseudomonas fluorescens. SAMNs were applied for mimicking Fe(3+) ions in solution, acting as magnetically drivable probes to evaluate putative Fe(3+) recognition sites on the microorganism surface. Culture broths and nano-bio-conjugates were characterized by UV-Vis spectroscopy and mass spectrometry. The whole heritage of a membrane porin (OprF) of P. fluorescens Ps_22 cells was recognized and firmly bound by SAMNs. The binding of nanoparticles to OprF porin was correlated to a drastic inhibition of a siderophore (pyoverdine) biosynthesis and to the stimulation of the production and rate of formation of a secondary siderophore. The analysis of metabolic pathways, based on P. fluorescens Ps_22 genomic information, evidenced that this putative secondary siderophore does not belong to a selection of the most common siderophores. In the scenario of an adhesion mechanism, it is plausible to consider OprF as the biological component deputed to the mineral iron sensing in P. fluorescens Ps_22, as well as one key of siderophore regulation. The present work sheds light on mineral iron sensing in microorganisms. Peculiar colloidal naked iron oxide nanoparticles offer a useful approach for probing the adhesion of bacterial surface on mineral iron for the identification of the specific recognition site for this iron uptake regulation in microorganisms. Copyright © 2016 Elsevier B.V. All rights reserved.

Lateral flow assay for rapid detection of white spot syndrome virus (WSSV) using a phage-displayed peptide as bio-recognition probe.

PubMed

Kulabhusan, Prabir Kumar; Rajwade, Jyutika M; Sahul Hameed, A S; Paknikar, Kishore M

2017-06-01

White spot disease caused by the white spot syndrome virus (WSSV) has a major socio-economic impact on shrimp farming in India. It has been realized that a field-usable diagnostic capable of rapid detection of WSSV can prevent huge economic losses in disease outbreaks. In this work, we explored the possibility of using a peptide as bio-recognition probe in a field-usable device for the detection of WSSV from infected shrimps and prawns. A commercially available random phage-display library was screened against rVP28 (a major structural protein of WSSV, expressed as a recombinant protein in Escherichia coli). A bacteriophage clone VP28-4L was obtained, and its binding to purified rVP28 protein as well as WSSV from infected shrimp Litopaeneus vannamei tissue was confirmed by ELISA and western blot. The apparent equilibrium dissociation constant (K d ,app) was calculated to be 810 nM. VP28-4L did not show cross-reactivity with any other shrimp viruses. A 12-mer peptide (pep28, with the sequence 'TFQAFDLSPFPS') displayed on the VP28-4L was synthesized, and its diagnostic potential was evaluated in a lateral flow assay (LFA). Visual detection of WSSV could be achieved using biotinylated-pep28 and streptavidin-conjugated gold nanoparticles. In LFA, 12.5 μg/mL of the virus could be detected from L. vannamei gill tissue homogenate within 20 min. Pep28 thus becomes an attractive candidate in bio-recognition of WSSV in field-usable diagnostic platforms benefitting the aquaculture sector.

Development of a real-time quantitative PCR assay to enumerate Yersinia pestis in fleas.

PubMed

Gabitzsch, Elizabeth S; Vera-Tudela, Rommelle; Eisen, Rebecca J; Bearden, Scott W; Gage, Kenneth L; Zeidner, Nordin S

2008-07-01

A real-time quantitative polymerase chain reaction (qPCR) assay was developed for Yersina pestis. The qPCR assay was developed utilizing a conserved region of the Y. pestis ferric iron uptake regulator gene (fur) to design primers and a fluorescent (FAM-labeled) TaqMan probe. The assay was optimized using cultured Y. pestis (UG05-0454) and was confirmed to work with strains from 3 Y. pestis biovars. The optimized assay was capable of detecting a single organism of cultured Y. pestis and as little as 300 bacteria in infected flea triturates. This qPCR assay enables rapid enumeration of Y. pestis bacterium in laboratory-infected fleas when compared with conventional serial dilution plating.

Strand displacement amplification as an in vitro model for rolling-circle replication: deletion formation and evolution during serial transfer.

PubMed Central

Walter, N G; Strunk, G

1994-01-01

Strand displacement amplification is an isothermal DNA amplification reaction based on a restriction endonuclease nicking its recognition site and a polymerase extending the nick at its 3' end, displacing the downstream strand. The reaction resembles rolling-circle replication of single-stranded phages and small plasmids. The displaced sense strand serves as target for an antisense reaction and vice versa, resulting in exponential growth and the autocatalytic nature of this in vitro reaction as long as the template is the limiting agent. We describe the optimization of strand displacement amplification for in vitro evolution experiments under serial transfer conditions. The reaction was followed and controlled by use of the fluorescent dye thiazole orange binding to the amplified DNA. We were able to maintain exponential growth conditions with a doubling time of 3.0 min throughout 100 transfers or approximately 350 molecular generations by using an automatic handling device. Homology of in vitro amplification with rolling-circle replication was mirrored by the occurring evolutionary processes. Deletion events most likely caused by a slipped mispairing mechanism as postulated for in vivo replication took place. Under our conditions, the mutation rate was high and a molecular quasi-species formed with a mutant lacking internal hairpin formation ability and thus outgrowing all other species under dGTP/dCTP deficiency. Images PMID:8058737

Composite faces are not (necessarily) processed coactively: A test using systems factorial technology and logical-rule models.

PubMed

Cheng, Xue Jun; McCarthy, Callum J; Wang, Tony S L; Palmeri, Thomas J; Little, Daniel R

2018-06-01

Upright faces are thought to be processed more holistically than inverted faces. In the widely used composite face paradigm, holistic processing is inferred from interference in recognition performance from a to-be-ignored face half for upright and aligned faces compared with inverted or misaligned faces. We sought to characterize the nature of holistic processing in composite faces in computational terms. We use logical-rule models (Fifić, Little, & Nosofsky, 2010) and Systems Factorial Technology (Townsend & Nozawa, 1995) to examine whether composite faces are processed through pooling top and bottom face halves into a single processing channel-coactive processing-which is one common mechanistic definition of holistic processing. By specifically operationalizing holistic processing as the pooling of features into a single decision process in our task, we are able to distinguish it from other processing models that may underlie composite face processing. For instance, a failure of selective attention might result even when top and bottom components of composite faces are processed in serial or in parallel without processing the entire face coactively. Our results show that performance is best explained by a mixture of serial and parallel processing architectures across all 4 upright and inverted, aligned and misaligned face conditions. The results indicate multichannel, featural processing of composite faces in a manner inconsistent with the notion of coactivity. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

A graphene-based biosensing platform based on the release of DNA probes and rolling circle amplification.

PubMed

Liu, Meng; Song, Jinping; Shuang, Shaomin; Dong, Chuan; Brennan, John D; Li, Yingfu

2014-06-24

We report a versatile biosensing platform capable of achieving ultrasensitive detection of both small-molecule and macromolecular targets. The system features three components: reduced graphene oxide for its ability to adsorb single-stranded DNA molecules nonspecifically, DNA aptamers for their ability to bind reduced graphene oxide but undergo target-induced conformational changes that facilitate their release from the reduced graphene oxide surface, and rolling circle amplification (RCA) for its ability to amplify a primer-template recognition event into repetitive sequence units that can be easily detected. The key to the design is the tagging of a short primer to an aptamer sequence, which results in a small DNA probe that allows for both effective probe adsorption onto the reduced graphene oxide surface to mask the primer domain in the absence of the target, as well as efficient probe release in the presence of the target to make the primer available for template binding and RCA. We also made an observation that the circular template, which on its own does not cause a detectable level of probe release from the reduced graphene oxide, augments target-induced probe release. The synergistic release of DNA probes is interpreted to be a contributing factor for the high detection sensitivity. The broad utility of the platform is illustrated though engineering three different sensors that are capable of achieving ultrasensitive detection of a protein target, a DNA sequence and a small-molecule analyte. We envision that the approach described herein will find useful applications in the biological, medical, and environmental fields.

Rapid Identification of Seven Waterborne Exophiala Species by RCA DNA Padlock Probes.

PubMed

Najafzadeh, M J; Vicente, V A; Feng, Peiying; Naseri, A; Sun, Jiufeng; Rezaei-Matehkolaei, A; de Hoog, G S

2018-03-05

The black yeast genus Exophiala includes numerous potential opportunistic species that potentially cause systematic and disseminated infections in immunocompetent individuals. Species causing systemic disease have ability to grow at 37-40 °C, while others consistently lack thermotolerance and are involved in diseases of cold-blooded, waterborne vertebrates and occasionally invertebrates. We explain a fast and sensitive assay for recognition and identification of waterborne Exophiala species without sequencing. The ITS rDNA region of seven Exophiala species (E. equina, E. salmonis, E. opportunistica, E. pisciphila, E. aquamarina, E. angulospora and E. castellanii) along with the close relative Veronaea botryosa was sequenced and aligned for the design of specific padlock probes for the detection of characteristic single-nucleotide polymorphisms. The assay demonstrated to successfully amplify DNA of target fungi, allowing detection at the species level. Amplification products were visualized on 1% agarose gels to confirm specificity of probe-template binding. Amounts of reagents were reduced to prevent the generation of false positive results. The simplicity, tenderness, robustness and low expenses provide padlock probe assay (RCA) a definite place as a very practical method among isothermal approaches for DNA diagnostics.

A functional applied material on recognition of metal ion zinc based on the double azine compound.

PubMed

Wei, Taibao; Liang, Guoyan; Chen, Xiaopeng; Qi, Jin; Lin, Qi; Zhang, Youming; Yao, Hong

2017-05-18

A colorimetric and fluorescent probe L has been designed and synthesized, which bearing the double azine moiety and showing a detection limit of 2.725 × 10 -7  M towards Zn 2+ . Based on the basic recognition mechanism of ESIPT and CHEF effect, the L has high selectivity and sensitivity to only Zn 2+ (not Fe 3+ , Hg 2+ , Ag + , Ca 2+ , Co 2+ , Ni 2+ , Cd 2+ , Pb 2+ , Cr 3+ , and Mg 2+ ) within the physiological pH range (pH = 7.0-8.4) and showed a fluorescence switch. Moreover, this detection progress occured in the DMSO/H 2 O ∼ HEPES buffer (80/20, v/v; pH 7.23) solution which can conveniently used on test strip.

Study of electromechanical and mechanical properties of bacteria using force microscopy

NASA Astrophysics Data System (ADS)

Reukov, Vladimir; Thompson, Gary; Nikiforov, Maxim; Guo, Senli; Ovchinnikov, Oleg; Jesse, Stephen; Kalinin, Sergei; Vertegel, Alexey

2010-03-01

The application of scanning probe microscopy (SPM) to biological systems has evolved over the past decade into a multimodal and spectroscopic instrument that provides multiple information channels at each spatial pixel acquired. Recently, functional recognition imaging based on differing electromechanical properties between Gram negative and Gram positive bacteria was achieved using artificial neural network analysis of band excitation piezoresponse force microscopy (BEPFM) data. The immediate goal of this project was to study mechanical and electromechanical properties of bacterial systems physiologically-relevant solutions using Band-width Excitation Piezoresponce Force Microscopy (BE PFM) in combination with Force Mapping. Electromechanical imaging in physiological environments will improve the versatility of functional recognition imaging and open the way for application of the rapid BEPFM line mode method to other living cell systems.

Probing Human Telomeric DNA and RNA Topology and Ligand Binding in a Cellular Model by Using Responsive Fluorescent Nucleoside Probes.

PubMed

Manna, Sudeshna; Panse, Cornelia H; Sontakke, Vyankat A; Sangamesh, Sarangamath; Srivatsan, Seergazhi G

2017-08-17

The development of biophysical systems that enable an understanding of the structure and ligand-binding properties of G-quadruplex (GQ)-forming nucleic acid sequences in cells or models that mimic the cellular environment would be highly beneficial in advancing GQ-directed therapeutic strategies. Herein, the establishment of a biophysical platform to investigate the structure and recognition properties of human telomeric (H-Telo) DNA and RNA repeats in a cell-like confined environment by using conformation-sensitive fluorescent nucleoside probes and a widely used cellular model, bis(2-ethylhexyl) sodium sulfosuccinate reverse micelles (RMs), is described. The 2'-deoxy and ribonucleoside probes, composed of a 5-benzofuran uracil base analogue, faithfully report the aqueous micellar core through changes in their fluorescence properties. The nucleoside probes incorporated into different loops of H-Telo DNA and RNA oligonucleotide repeats are minimally perturbing and photophysically signal the formation of respective GQ structures in both aqueous buffer and RMs. Furthermore, these sensors enable a direct comparison of the binding affinity of a ligand to H-Telo DNA and RNA GQ structures in the bulk and confined environment of RMs. These results demonstrate that this combination of a GQ nucleoside probe and easy-to-handle RMs could provide new opportunities to study and devise screening-compatible assays in a cell-like environment to discover GQ binders of clinical potential. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A lysosome-targetable turn-on fluorescent probe for the detection of thiols in living cells based on a 1,8-naphthalimide derivative.

PubMed

Liang, Beibei; Wang, Baiyan; Ma, Qiujuan; Xie, Caixia; Li, Xian; Wang, Suiping

2018-03-05

Biological thiols, like cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), play crucial roles in biological systems and in lysosomal processes. Highly selective probes for detecting biological thiols in lysomes of living cells are rare. In this work, a lysosome-targetable turn-on fluorescent probe for the detection of thiols in living cells was designed and synthesized based on a 1,8-naphthalimide derivative. The probe has a 4-(2-aminoethyl)morpholine unit as a lysosome-targetable group and an acrylate group as the thiol recognition unit as well as a fluorescence quencher. In the absence of biothiols, the probe displayed weak fluorescence due to the photoinduced electron transfer (PET) process. Upon the addition of biothiols, the probe exhibited an enhanced fluorescence emission centered at 550nm due to cleavage of the acrylate moiety. The probe had high selectivity toward biothiols. Moreover, the probe features fast response time, excitation in the visible region and ability of working in a wide pH range. The linear response range covers a concentration range of Cys from 1.5×10 -7 to 1.0×10 -5 mol·L -1 and the detection limit is 6.9×10 -8 mol·L -1 for Cys. The probe has been successfully applied to the confocal imaging of biothiols in lysosomes of A549 cells with low cell toxicity. Furthermore, the method was successfully applied to the determination of thiols in a complex multicomponent mixture such as human serum, which suggests our proposed method has great potential for diagnostic purposes. All of such good properties prove it can be used to monitor biothiols in lysosomes of living cells and to be a good fluorescent probe for the selective detection of thiols. Copyright © 2017 Elsevier B.V. All rights reserved.

Neuropsychological profile and social cognition in congenital central hypoventilation syndrome (CCHS): Correlation with neuroimaging in a clinical case.

PubMed

Esteso Orduña, Borja; Seijas Gómez, Raquel; García Esparza, Elena; Briceño, Emily M; Melero Llorente, Javier; Fournier Del Castillo, María de la Concepción

2018-02-01

Congenital central hypoventilation syndrome (CCHS) is a rare genetic disorder due to paired-like homeobox gene (PHOX2B) mutations. CCHS patients suffer from dysregulation of the autonomic nervous system characterized by the absence of or extremely reduced response to hypercapnia and hypoxia, with neuropsychological deficits. The aim of this exploratory study is to describe the longitudinal neuropsychological profile and its correlations with magnetic resonance imaging (MRI) of a child with CCHS with a PHOX2B mutation. A comprehensive neuropsychological evaluation was conducted serially at age 7 years 4 months and 10 years 3 months, including assessment of intellectual functioning (IQ), motor functioning, perception, attention, executive functions, language, memory, social cognition, academic skills, and psychopathology. Reliable change index (RCI) scores were used to assess changes between assessments. We collected spin lattice relaxation time (T1)-weighted, fluid-attenuated inversion recovery (FLAIR), and spin spin lattice relaxation time (T2)-weighted images from the child at age 10 years 3 months using a 1.5-tesla MRI scanner. IQ, processing speed index (PSI), social cognition (theory of mind and facial emotion recognition), selective attention, naming, academic skills (reading/comprehension), and manual speed with right hand declined in the second evaluation relative to the initial evaluation, while visuoconstructional praxis, receptive vocabulary, working memory, and arithmetic skill improved. The patient showed a remarkable global deterioration in executive functions (planning, task flexibility, behavioral regulation, and metacognition) as revealed by parental report and clinical evaluation. MRI revealed gliosis from the head to tail of the hippocampus and thinning of parahippocampal gyri. In a clinical case of CCHS, serial evaluation revealed deterioration of executive functions and social cognition over a 3-year interval. These changes corresponded to hippocampal damage as revealed in MRI, which may have affected social cognition through its role in the default mode network. Serial neuropsychological assessment is clinically useful in managing the needs of these patients.

Sequential combination of multi-source satellite observations for separation of surface deformation associated with serial seismic events

NASA Astrophysics Data System (ADS)

Chen, Qiang; Xu, Qian; Zhang, Yijun; Yang, Yinghui; Yong, Qi; Liu, Guoxiang; Liu, Xianwen

2018-03-01

Single satellite geodetic technique has weakness for mapping sequence of ground deformation associated with serial seismic events, like InSAR with long revisiting period readily leading to mixed complex deformation signals from multiple events. It challenges the observation capability of single satellite geodetic technique for accurate recognition of individual surface deformation and earthquake model. The rapidly increasing availability of various satellite observations provides good solution for overcoming the issue. In this study, we explore a sequential combination of multiple overlapping datasets from ALOS/PALSAR, ENVISAT/ASAR and GPS observations to separate surface deformation associated with the 2011 Mw 9.0 Tohoku-Oki major quake and two strong aftershocks including the Mw 6.6 Iwaki and Mw 5.8 Ibaraki events. We first estimate the fault slip model of major shock with ASAR interferometry and GPS displacements as constraints. Due to the used PALSAR interferogram spanning the period of all the events, we then remove the surface deformation of major shock through forward calculated prediction thus obtaining PALSAR InSAR deformation associated with the two strong aftershocks. The inversion for source parameters of Iwaki aftershock is conducted using the refined PALSAR deformation considering that the higher magnitude Iwaki quake has dominant deformation contribution than the Ibaraki event. After removal of deformation component of Iwaki event, we determine the fault slip distribution of Ibaraki shock using the remained PALSAR InSAR deformation. Finally, the complete source models for the serial seismic events are clearly identified from the sequential combination of multi-source satellite observations, which suggest that the major quake is a predominant mega-thrust rupture, whereas the two aftershocks are normal faulting motion. The estimated seismic moment magnitude for the Tohoku-Oki, Iwaki and Ibaraki evens are Mw 9.0, Mw 6.85 and Mw 6.11, respectively.

One step screening of retroviral producer clones by real time quantitative PCR.

PubMed

Towers, G J; Stockholm, D; Labrousse-Najburg, V; Carlier, F; Danos, O; Pagès, J C

1999-01-01

Recombinant retroviruses are obtained from either stably or transiently transfected retrovirus producer cells. In the case of stably producing lines, a large number of clones must be screened in order to select the one with the highest titre. The multi-step selection of high titre producing clones is time consuming and expensive. We have taken advantage of retroviral endogenous reverse transcription to develop a quantitative PCR assay on crude supernatant from producing clones. We used Taqman PCR technology, which, by using fluorescence measurement at each cycle of amplification, allows PCR product quantification. Fluorescence results from specific degradation of a probe oligonucleotide by the Taq polymerase 3'-5' exonuclease activity. Primers and probe sequences were chosen to anneal to the viral strong stop species, which is the first DNA molecule synthesised during reverse transcription. The protocol consists of a single real time PCR, using as template filtered viral supernatant without any other pre-treatment. We show that the primers and probe described allow quantitation of serially diluted plasmid to as few as 15 plasmid molecules. We then test 200 GFP-expressing retroviral-producing clones either by FACS analysis of infected cells or by using the quantitative PCR. We confirm that the Taqman protocol allows the detection of virus in supernatant and selection of high titre clones. Furthermore, we can determine infectious titre by quantitative PCR on genomic DNA from infected cells, using an additional set of primers and probe to albumin to normalise for the genomic copy number. We demonstrate that real time quantitative PCR can be used as a powerful and reliable single step, high throughput screen for high titre retroviral producer clones.

Specific Recognition and Detection of MRSA Based on Molecular Probes Comprised of Lytic Phage and Antibody

DTIC Science & Technology

2011-03-29

QCM system was employed to study bacteria-phage interactions. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 1 18... QCM -D system (Sweden) was employed to study bacteria-phage interactions. Lytic phages were constructed into hollow spherical particles upon exposure to...a chloroform-water interface. These particles were converted into monolayers and deposited onto QCM -D crystals using Langmuir-Blodgett technique [I

Serial killers with military experience: applying learning theory to serial murder.

PubMed

Castle, Tammy; Hensley, Christopher

2002-08-01

Scholars have endeavored to study the motivation and causality behind serial murder by researching biological, psychological, and sociological variables. Some of these studies have provided support for the relationship between these variables and serial murder. However, the study of serial murder continues to be an exploratory rather than explanatory research topic. This article examines the possible link between serial killers and military service. Citing previous research using social learning theory for the study of murder, this article explores how potential serial killers learn to reinforce violence, aggression, and murder in military boot camps. As with other variables considered in serial killer research, military experience alone cannot account for all cases of serial murder. Future research should continue to examine this possible link.

Surface-functionalized nanoparticles for biosensing and imaging-guided therapeutics

NASA Astrophysics Data System (ADS)

Jiang, Shan; Win, Khin Yin; Liu, Shuhua; Teng, Choon Peng; Zheng, Yuangang; Han, Ming-Yong

2013-03-01

In this article, the very recent progress of various functional inorganic nanomaterials is reviewed including their unique properties, surface functionalization strategies, and applications in biosensing and imaging-guided therapeutics. The proper surface functionalization renders them with stability, biocompatibility and functionality in physiological environments, and further enables their targeted use in bioapplications after bioconjugation via selective and specific recognition. The surface-functionalized nanoprobes using the most actively studied nanoparticles (i.e., gold nanoparticles, quantum dots, upconversion nanoparticles, and magnetic nanoparticles) make them an excellent platform for a wide range of bioapplications. With more efforts in recent years, they have been widely developed as labeling probes to detect various biological species such as proteins, nucleic acids and ions, and extensively employed as imaging probes to guide therapeutics such as drug/gene delivery and photothermal/photodynamic therapy.

‘Protected DNA Probes’ capable of strong hybridization without removal of base protecting groups

PubMed Central

Ohkubo, Akihiro; Kasuya, Rintaro; Sakamoto, Kazushi; Miyata, Kenichi; Taguchi, Haruhiko; Nagasawa, Hiroshi; Tsukahara, Toshifumi; Watanobe, Takuma; Maki, Yoshiyuki; Seio, Kohji; Sekine, Mitsuo

2008-01-01

We propose a new strategy called the ‘Protected DNA Probes (PDP) method’ in which appropriately protected bases selectively bind to the complementary bases without the removal of their base protecting groups. Previously, we reported that 4-N-acetylcytosine oligonucleotides (ac4C) exhibited a higher hybridization affinity for ssDNA than the unmodified oligonucleotides. For the PDP strategy, we created a modified adenine base and synthesized an N-acylated deoxyadenosine mimic having 6-N-acetyl-8-aza-7-deazaadenine (ac6az8c7A). It was found that PDP containing ac4C and ac6az8c7A exhibited higher affinity for the complementary ssDNA than the corresponding unmodified DNA probes and showed similar base recognition ability. Moreover, it should be noted that this PDP strategy could guarantee highly efficient synthesis of DNA probes on controlled pore glass (CPG) with high purity and thereby could eliminate the time-consuming procedures for isolating DNA probes. This strategy could also avoid undesired base-mediated elimination of DNA probes from CPG under basic conditions such as concentrated ammonia solution prescribed for removal of base protecting groups in the previous standard approach. Here, several successful applications of this strategy to single nucleotide polymorphism detection are also described in detail using PDPs immobilized on glass plates and those prepared on CPG plates, suggesting its potential usefulness. PMID:18272535

New detection targets for amyloid-reactive probes: spectroscopic recognition of bacterial spores

NASA Astrophysics Data System (ADS)

Jones, Guilford, II; Landsman, Pavel

2005-05-01

We report characteristic changes in fluorescence of amyloid-binding dyes Thioflavin T (TfT), pinacyanol (PIN) and related dyes, caused by their interaction with suspended Bacillus spore cultures (B. subtilis, B thuringiensis). The gain in TfT emission in the presence of spores allowed their immediate detection in aqueous suspensions, with a sensitivity limit of < 105 spores per ml. The spectroscopic signatures are consistent with a large number of binding sites for the two dyes on spore coats. The possible structural relationship of these dye binding loci with characteristic motifs (β-stacks) of amyloid deposits and other misfolded protein formations suggests new designs for probing biocontamination and also for clinical studies of non-microbial human pathogens (e.g., amyloid-related protein aggregates in prion-related transmissible encephalopathies or in Alzheimer's disease). Also reported is a special screening technique that was designed and used herein for calibration of new detection probes and assays for spore detection. It employed spectroscopic interactions between the candidate amyloid stains and poly(vinylpyrrolidone)-coated colloid silica (Percoll) nanoparticles that also display remarkable parallelism with the corresponding dye-amyloid and dye-spore reactivities. Percoll may thus find new applications as a convenient non-biological structural model mimicking the putative probe-targeted motifs in both classes of bioanalytes. These findings are important in the design of new probes and assays for important human pathogens (i.e. bacterial spores and amyloidogenic protein aggregates).

In situ monitoring of cytoplasmic precursor and mature microRNA using gold nanoparticle and graphene oxide composite probes.

PubMed

Hong, Min; Sun, Hongxiao; Xu, Lidan; Yue, Qiaoli; Shen, Guodong; Li, Meifang; Tang, Bo; Li, Chen-Zhong

2018-08-27

This study strategically fabricates a nucleic acid functionalized gold nanoparticle and graphene oxide composite probe (AuNP/GO probe) to achieve both the recognition and in situ monitoring of cytoplasmic target precursor microRNAs (pre-miRNAs) and mature microRNAs (miRNAs) in living cells. The pre-miRNA-21 detection with AuNP probes has a good linear range of 0-300 nM and a limit of detection (LOD) of 4.5 nM, whereas the GO probe has a linear relationship with mature miRNA-21 from 0.1 to 10 nM with a LOD of 1.74 nM. This assay was utilized to directly visualize the relative expression levels of pre- and mature forms of miRNA-21 and let-7a. The results suggested that the expression levels of precursor miRNAs remain constant in cancer cells and normal cells. However, the expression levels of mature miRNAs vary widely, demonstrating the "up-regulation" of miRNA-21 and "down-regulation" of let-7a in cancer cells in contrast to that in normal cells. The practicality of this strategy was verified by in situ monitoring changes in cytoplasmic pre-miRNA-21 and mature miRNA-21 in response to small-molecule inhibitors of miRNA-21. Copyright © 2018 Elsevier B.V. All rights reserved.

Report on the Current Inventory of the Toolbox for Plant Cell Wall Analysis: Proteinaceous and Small Molecular Probes

PubMed Central

Rydahl, Maja G.; Hansen, Aleksander R.; Kračun, Stjepan K.; Mravec, Jozef

2018-01-01

Plant cell walls are highly complex structures composed of diverse classes of polysaccharides, proteoglycans, and polyphenolics, which have numerous roles throughout the life of a plant. Significant research efforts aim to understand the biology of this cellular organelle and to facilitate cell-wall-based industrial applications. To accomplish this, researchers need to be provided with a variety of sensitive and specific detection methods for separate cell wall components, and their various molecular characteristics in vitro as well as in situ. Cell wall component-directed molecular detection probes (in short: cell wall probes, CWPs) are an essential asset to the plant glycobiology toolbox. To date, a relatively large set of CWPs has been produced—mainly consisting of monoclonal antibodies, carbohydrate-binding modules, synthetic antibodies produced by phage display, and small molecular probes. In this review, we summarize the state-of-the-art knowledge about these CWPs; their classification and their advantages and disadvantages in different applications. In particular, we elaborate on the recent advances in non-conventional approaches to the generation of novel CWPs, and identify the remaining gaps in terms of target recognition. This report also highlights the addition of new “compartments” to the probing toolbox, which is filled with novel chemical biology tools, such as metabolic labeling reagents and oligosaccharide conjugates. In the end, we also forecast future developments in this dynamic field. PMID:29774041

The eyeball killer: serial killings with postmortem globe enucleation.

PubMed

Coyle, Julie; Ross, Karen F; Barnard, Jeffrey J; Peacock, Elizabeth; Linch, Charles A; Prahlow, Joseph A

2015-05-01

Although serial killings are relatively rare, they can be the cause of a great deal of anxiety while the killer remains at-large. Despite the fact that the motivations for serial killings are typically quite complex, the psychological analysis of a serial killer can provide valuable insight into how and why certain individuals become serial killers. Such knowledge may be instrumental in preventing future serial killings or in solving ongoing cases. In certain serial killings, the various incidents have a variety of similar features. Identification of similarities between separate homicidal incidents is necessary to recognize that a serial killer may be actively killing. In this report, the authors present a group of serial killings involving three prostitutes who were shot to death over a 3-month period. Scene and autopsy findings, including the unusual finding of postmortem enucleation of the eyes, led investigators to recognize the serial nature of the homicides. © 2015 American Academy of Forensic Sciences.

Evaluation of Feature Extraction and Recognition for Activity Monitoring and Fall Detection Based on Wearable sEMG Sensors.

PubMed

Xi, Xugang; Tang, Minyan; Miran, Seyed M; Luo, Zhizeng

2017-05-27

As an essential subfield of context awareness, activity awareness, especially daily activity monitoring and fall detection, plays a significant role for elderly or frail people who need assistance in their daily activities. This study investigates the feature extraction and pattern recognition of surface electromyography (sEMG), with the purpose of determining the best features and classifiers of sEMG for daily living activities monitoring and fall detection. This is done by a serial of experiments. In the experiments, four channels of sEMG signal from wireless, wearable sensors located on lower limbs are recorded from three subjects while they perform seven activities of daily living (ADL). A simulated trip fall scenario is also considered with a custom-made device attached to the ankle. With this experimental setting, 15 feature extraction methods of sEMG, including time, frequency, time/frequency domain and entropy, are analyzed based on class separability and calculation complexity, and five classification methods, each with 15 features, are estimated with respect to the accuracy rate of recognition and calculation complexity for activity monitoring and fall detection. It is shown that a high accuracy rate of recognition and a minimal calculation time for daily activity monitoring and fall detection can be achieved in the current experimental setting. Specifically, the Wilson Amplitude (WAMP) feature performs the best, and the classifier Gaussian Kernel Support Vector Machine (GK-SVM) with Permutation Entropy (PE) or WAMP results in the highest accuracy for activity monitoring with recognition rates of 97.35% and 96.43%. For fall detection, the classifier Fuzzy Min-Max Neural Network (FMMNN) has the best sensitivity and specificity at the cost of the longest calculation time, while the classifier Gaussian Kernel Fisher Linear Discriminant Analysis (GK-FDA) with the feature WAMP guarantees a high sensitivity (98.70%) and specificity (98.59%) with a short calculation time (65.586 ms), making it a possible choice for pre-impact fall detection. The thorough quantitative comparison of the features and classifiers in this study supports the feasibility of a wireless, wearable sEMG sensor system for automatic activity monitoring and fall detection.

Evaluation of Feature Extraction and Recognition for Activity Monitoring and Fall Detection Based on Wearable sEMG Sensors

PubMed Central

Xi, Xugang; Tang, Minyan; Miran, Seyed M.; Luo, Zhizeng

2017-01-01

As an essential subfield of context awareness, activity awareness, especially daily activity monitoring and fall detection, plays a significant role for elderly or frail people who need assistance in their daily activities. This study investigates the feature extraction and pattern recognition of surface electromyography (sEMG), with the purpose of determining the best features and classifiers of sEMG for daily living activities monitoring and fall detection. This is done by a serial of experiments. In the experiments, four channels of sEMG signal from wireless, wearable sensors located on lower limbs are recorded from three subjects while they perform seven activities of daily living (ADL). A simulated trip fall scenario is also considered with a custom-made device attached to the ankle. With this experimental setting, 15 feature extraction methods of sEMG, including time, frequency, time/frequency domain and entropy, are analyzed based on class separability and calculation complexity, and five classification methods, each with 15 features, are estimated with respect to the accuracy rate of recognition and calculation complexity for activity monitoring and fall detection. It is shown that a high accuracy rate of recognition and a minimal calculation time for daily activity monitoring and fall detection can be achieved in the current experimental setting. Specifically, the Wilson Amplitude (WAMP) feature performs the best, and the classifier Gaussian Kernel Support Vector Machine (GK-SVM) with Permutation Entropy (PE) or WAMP results in the highest accuracy for activity monitoring with recognition rates of 97.35% and 96.43%. For fall detection, the classifier Fuzzy Min-Max Neural Network (FMMNN) has the best sensitivity and specificity at the cost of the longest calculation time, while the classifier Gaussian Kernel Fisher Linear Discriminant Analysis (GK-FDA) with the feature WAMP guarantees a high sensitivity (98.70%) and specificity (98.59%) with a short calculation time (65.586 ms), making it a possible choice for pre-impact fall detection. The thorough quantitative comparison of the features and classifiers in this study supports the feasibility of a wireless, wearable sEMG sensor system for automatic activity monitoring and fall detection. PMID:28555016

Get the gist? The effects of processing depth on false recognition in short-term and long-term memory.

PubMed

Flegal, Kristin E; Reuter-Lorenz, Patricia A

2014-07-01

Gist-based processing has been proposed to account for robust false memories in the converging-associates task. The deep-encoding processes known to enhance verbatim memory also strengthen gist memory and increase distortions of long-term memory (LTM). Recent research has demonstrated that compelling false memory illusions are relatively delay-invariant, also occurring under canonical short-term memory (STM) conditions. To investigate the contributions of gist to false memory at short and long delays, processing depth was manipulated as participants encoded lists of four semantically related words and were probed immediately, following a filled 3- to 4-s retention interval, or approximately 20 min later, in a surprise recognition test. In two experiments, the encoding manipulation dissociated STM and LTM on the frequency, but not the phenomenology, of false memory. Deep encoding at STM increases false recognition rates at LTM, but confidence ratings and remember/know judgments are similar across delays and do not differ as a function of processing depth. These results suggest that some shared and some unique processes underlie false memory illusions at short and long delays.

Is visual image segmentation a bottom-up or an interactive process?

PubMed

Vecera, S P; Farah, M J

1997-11-01

Visual image segmentation is the process by which the visual system groups features that are part of a single shape. Is image segmentation a bottom-up or an interactive process? In Experiments 1 and 2, we presented subjects with two overlapping shapes and asked them to determine whether two probed locations were on the same shape or on different shapes. The availability of top-down support was manipulated by presenting either upright or rotated letters. Subjects were fastest to respond when the shapes corresponded to familiar shapes--the upright letters. In Experiment 3, we used a variant of this segmentation task to rule out the possibility that subjects performed same/different judgments after segmentation and recognition of both letters. Finally, in Experiment 4, we ruled out the possibility that the advantage for upright letters was merely due to faster recognition of upright letters relative to rotated letters. The results suggested that the previous effects were not due to faster recognition of upright letters; stimulus familiarity influenced segmentation per se. The results are discussed in terms of an interactive model of visual image segmentation.