Position Of Tag Research Articles

Yeast Complementation Assays Demonstrating the Importance of the Affinity Tag Position in Membrane Protein Purification, as Exemplified by HpUreI, the pH‐Gated Urea Channel of Helicobacter pylori

Affinity tags are a crucial component in protein purification. Despite several indications that they can influence protein structure and function, this influence is often unknown or disregarded. This unnecessarily introduces ambiguity in the interpretation of in vitro data. To illustrate that, urea and ammonia yeast complementation assays are used as a screening tool to assess functional differences in various affinity tag positions, compared to the WT protein, using HpUreI, an acid‐gated urea channel of Helicobacter pylori. Yeast complementation assays test the pH‐dependent functionality of exogenous proteins expressed in deletion strains by observing growth. If the exogenous protein is able to replace the function of the deleted endogenous protein, yeast cells can demonstrate growth under specific assay conditions. The overall tag position and even a minor amount of residual N‐ or C‐terminal amino acids following tag cleavage exert a solute‐specific influence on HpUreI functionality, suggesting a complex solute selectivity mechanism and underscores the necessity for in vivo characterization. This cost‐effective yeast complementation assay can be adapted to test a broad range of solutes. It can be used as a preliminary screening tool for affinity tag positions or protein mutations before quantitative in vitro protein characterization.

Challenges and advances for huntingtin detection in cerebrospinal fluid: in support of relative quantification.

Huntington disease (HD) is a progressive and devastating neurodegenerative disease caused by expansion of a glutamine-coding CAG tract in the huntingtin (HTT) gene above a critical threshold of ~35 repeats resulting in expression of mutant HTT (mHTT). A promising treatment approach being tested in clinical trials is HTT lowering, which aims to reduce levels of the mHTT protein. Target engagement of these therapies in the brain are inferred using antibody-based assays to measure mHTT levels in the cerebrospinal fluid (CSF), which is frequently reported as absolute mHTT concentration based on a monomeric protein standard used to generate a standard curve. However, patient biofluids are a complex milieu of different mHTT protein species, suggesting that absolute quantitation is challenging, and a single, recombinant protein standard may not be sufficient to interpret assay signal as molar mHTT concentration. In this study, we used immunoprecipitation and flow cytometry (IP-FCM) to investigate different factors that influence mHTT detection assay signal. Our results show that HTT protein fragmentation, protein-protein interactions, affinity tag positioning, oligomerization and polyglutamine tract length affect assay signal intensity, indicating that absolute HTT quantitation in heterogeneous biological samples is not possible with current technologies using a single standard protein. We also explore the binding specificity of the MW1 anti-polyglutamine antibody, commonly used in these assays as a mHTT-selective reagent and demonstrate that mHTT binding is preferred but not specific. Furthermore, we find that MW1 depletion is not only incomplete, leaving residual mHTT, but also non-specific, resulting in pull down of some wildtype HTT protein. Based on these observations, we recommend that mHTT detection assays report only relative mHTT quantitation using normalized arbitrary units of assay signal intensity, rather than molar concentrations, in the assessment of central nervous system HTT lowering in ongoing clinical and preclinical studies, and that MW1-depletion not be used a method for quantifying wildtype HTT protein.

Radiofrequency as a method of localizing impalpable breast lesions

BackgroundThe incidence of early stage breast cancer has risen as a result of increased detection of non-palpable tumors through the implementation of screening programs and greater public awareness. Performing breast-conserving surgery can be challenging due to the need for accurate localization of non-palpable breast lesions, particularly given the logistical difficulties associated with wire localization. After implementing a new technique for localizing non-palpable breast lesions (LOCalizerTM Radiofrequency identification TAG-Hologic®), a radiofrequency identification tag localization device manufactured by Hologic, Inc. in Marlborough, MA, was launched in 2017, our objective was to investigate its impact on surgical outcomes, whether there was an increase in re-excision rates for positive margins and whether the attainment of clear margins was dependent on the exact positioning of the RFID device. MethodA single-center single-arm interventional study, data were gathered both in a forward-looking manner for 1 year (prospectively) and by looking back at past records for 1 year (retrospectively) for a total period of two years. Individuals who were diagnosed with non-palpable breast lesions, as confirmed by histological analysis, or invasive breast cancer and who were scheduled to undergo breast-conserving surgery were eligible for inclusion in the study. The RFID (Radiofrequency Identification) method was used to localize the lesions prior to surgery. Either with a mammogram or ultrasound scan position of the Tag was recorded, including the distance of the lesion from the center of the lesion and the lesion depth from the skin in millimeters. The rate of re-excision was documented and examined in relation to the parameters mentioned above. ResultsTwo hundred and twenty RFID Tags were inserted in two hundred and seventeen (three patient had bilateral tags insertion), patients aged between 30 and 85 had a localizer Tag inserted between Oct 2020 and Oct 2022. Three patients had non-palpable breast lesions in both breasts. Fourteen were inserted under stereotactic guidance and two hundred and six under ultrasound guidance. Ten patients subsequently had wire insertion also due to Tag position. Of 210 procedures, RFIF Tags within the lesion was seen in hundred and sixty patients (76.19 %). An additional 50 procedures were performed using the RFID Tag system, which were not directly related to the lesion but were deemed appropriate to proceed with.Out of a total of 220 procedures, positive margins were observed in 38 cases (17.27 %). Among these cases, eleven (28.94 %) involved the use of the RFID Tag system, not within the lesion but adjacent to it (within 15 mm surrounding the lesion). ConclusionRFID is a good alternative to wire localization of non-palpable breast lesions. Re-excision rates are higher in patients with Tag outside the lesion compared to those with Tag within the lesion.

The Evolution of Lipidomics during Oil Accumulation of Plukenetia volubilis Seeds.

Sacha inchi (Plukenetia volubilis) is a valuable oilseed crop with a high content of polyunsaturated fatty acids (PUFAs). However, there is a lack of in-depth understanding of the lipidomics in Sacha inchi seeds (SIDs). Saturated fatty acids occupied more than half of the proportion (59.31%) in early development, while PUFAs accounted for 78.92% at maturation. The main triacylglycerols were TAG(18:3/18:3/18:3), TAG(18:2/18:2/18:3), and TAG(16:0/18:2/18:2). The corresponding species (18:3/18:3, 18:2/18:2, and 16:0/18:2) were also the main ingredients in diacylglycerol and phosphatidic acid, indicating high PUFA composition in the sn-1 and sn-2 positions of TAG. Only LPC(18:3), LPC(18:2), and LPC(16:0) were identified in SIDs, implying that those PUFAs on the sn-2 positions of the PC(18:3/-), PC(18:2/-), and PC(16:0/-) categories were released into the acyl-CoA pool for the Kennedy pathway. Conversely, the PC(18:1/-) and PC(18:0/-) categories might be responsible for the generation of PC-derived DAG and TAG. The lipidomics data will contribute to understanding the TAG assembly in developing SIDs, especially for PUFAs.

Mixed reality head mounted displays for enhanced indoor point cloud segmentation with virtual seeds

Mixed Reality (MR) Head Mounted Displays (HMDs) offer a hitherto underutilized set of advantages compared to conventional 3D scanners. These benefits, inherent to MR-HMDs albeit not originally intended for such applications, encompass the freedom of hand movement, hand tracking capabilities, and real-time mesh visualization. This study leverages these attributes to enhance indoor scanning process. The primary innovation lies in the conceptualization of manual-positioned MR virtual seeds for the purpose of indoor point cloud segmentation via a region-growing approach. The proposed methodology is effectively implemented using the HoloLens 2 platform. An application is designed to enable the remote placement of virtual tags based on the user's visual focus on the MR-HMD display. This non-intrusive interface is further enriched with expedited tag saving and deletion functionalities, as well as augmented tag visualization through overlaying them on real-world objects. To assess the practicality of the proposed method, a comprehensive real-world case study spanning an area of 330 s2 is conducted. Remarkably, the survey demonstrates remarkable efficiency, with 20 virtual tags swiftly deployed, each requiring a mere 2 s for precise positioning. Subsequently, these virtual tags are employed as seeds in a region-growing algorithm for point cloud segmentation. The accuracy of virtual tag positioning is found to be exceptional, with an average error of 2.4 ± 1.8 cm. Importantly, the user experience is significantly enhanced, leading to improved seed positioning and, consequently, more accurate final segmentation results.

Harmonic FMCW Radar System: Passive Tag Detection and Precise Ranging Estimation.

This paper details the design and implementation of a harmonic frequency-modulated continuous-wave (FMCW) radar system, specialized in detecting harmonic tags and achieving precise range estimation. Operating within the 2.4-2.5 GHz frequency range for the forward channel and 4.8-5.0 GHz for the backward channel, this study delves into the various challenges faced during the system's realization. These challenges include selecting appropriate components, calibrating the system, processing signals, and integrating the system components. In addition, we introduce a single-layer passive harmonic tag, developed specifically for assessing the system, and provide an in-depth theoretical analysis and simulation results. Notably, the system is characterized by its low power consumption, making it particularly suitable for short-range applications. The system's efficacy is further validated through experimental evaluations in a real-world indoor environment across multiple tag positions. Our measurements underscore the system's robust ranging accuracy and its ability to mitigate self-interference, showcasing its significant potential for applications in harmonic tag detection and ranging.

SALOS-A UWB Single-Anchor Indoor Localization System Based on a Statistical Multipath Propagation Model.

Among other methods, UWB-based multi-anchor localization systems have been established for industrial indoor localization systems. However, multi-anchor systems have high costs and installation effort. By exploiting the multipath propagation of the UWB signal, the infrastructure and thus the costs of conventional systems can be reduced. Our UWB Single-Anchor Localization System (SALOS) successfully pursues this approach. The idea is to create a localization system with sophisticated signal modeling. Therefore, measured reference, like fingerprinting or training, is not required for position estimation. Although SALOS has already been implemented and tested successfully in an outdoor scenario with multipath propagation, it has not yet been evaluated in an indoor environment with challenging and hardly predictable multipath propagation. For this purpose, we have developed new algorithms for the existing hardware, mainly a three-dimensional statistical multipath propagation model for arbitrary spatial geometries. The signal propagation between the anchor and predefined candidate points for the tag position is modeled in path length and complex-valued receive amplitudes. For position estimation, these modeled signals are combined to multiple sets and compared to UWB measurements via a similarity metric. Finally, a majority decision of multiple position estimates is performed. For evaluation, we implement our localization system in a modular fashion and install the system in a building. For a fixed grid of 20 positions, the localization is evaluated in terms of position accuracy. The system results in correct position estimations for more than 73% of the measurements.

Expression and Purification of His-Tagged Variants of Human Hepatitis A Virus 3C Protease.

Protease 3C (3Cpro) is the only protease encoded in the human hepatitis A virus genome and is considered as a potential target for antiviral drugs due to its critical role in the viral life cycle. Additionally, 3Cpro has been identified as a potent inducer of ferroptosis, a newly described type of cell death. Therefore, studying the molecular mechanism of 3Cpro functioning can provide new insights into viral-host interaction and the biological role of ferroptosis. However, such studies require a reliable technique for producing the functionally active recombinant enzyme. Here, we expressed different modified forms of 3Cpro with a hexahistidine tag on the N- or C-terminus to investigate the applicability of immobilized metal Ion affinity chromatography (IMAC) for producing 3Cpro. We expressed the proteins in Escherichia coli and purified them using IMAC, followed by gel permeation chromatography. The enzymatic activity of the produced proteins was assayed using a specific chromogenic substrate. Our findings showed that the introduction and position of the hexahistidine tag did not affect the activity of the enzyme. However, the yield of the target protein was highest for the variant with seven C-terminal residues replaced by a hexahistidine sequence. We demonstrated the applicability of our approach for producing recombinant, enzymatically active 3Cpro.

Ergonomic RFID tag placement on surgical instruments- a preliminary user study.

RFID tags on surgical instruments allow tracking of individual instruments. However, the tags on the instruments can restrict the handling, potentially increasing patient risks. Previous studies analyzed hand contact areas to identify potential locations for tags. However, the studies did not conduct interaction tests using instruments equipped with RFID tags, potentially neglecting the influence of haptic perception. In addition, previous studies required time-consuming evaluations by clinicians. Therefore, the present study aims to verify the previous findings in interaction-centered tests with clinicians using real RFID tags on the instruments. Additionally, we had instrument design experts rate RFID tag positions and examined whether they could predict the clinician's preferred tag positions. We found that nearly all RFID tag positions decreased the user satisfaction of clinicians compared to a reference instrument. Compared to previous studies, our study shows that the RFID tag influences the orientations in which an instrument can be comfortably held, which was criticized by clinicians. Instrument design experts could only predict the clinician's preferred tag positions for some instruments. Therefore, we recommend investigating further changes to instrument design, for what the "ideal" positions proposed by the clinicians in this study can provide initial pointers.

Estimating internal transmitter and external tag retention by Walleye in the Laurentian Great Lakes over multiple years

AbstractObjectiveBoth electronic tags (e.g., acoustic and radio transmitters) and conventional external tags are used to evaluate movement and population dynamics of fish. External tags are also sometimes used to facilitate the recovery of internal electronic tags or other instrumentation because healing can make it difficult to identify fish with internal tags based on appearance alone. With both tag types, tag shedding and failure of electronic tags can affect accuracy and precision of study results.MethodsWe used a decade (2011–2021) of recapture data for Walleye Sander vitreus tagged in the Laurentian Great Lakes, where fish were double‐ or triple‐tagged with external tags (T‐bar, loop, or internal anchor tags) and internal acoustic transmitters, to quantify external tag and internal transmitter shedding and transmitter failure rates.ResultIn total, 1125 (33%) Walleye were recovered that had retained at least one external tag or internal transmitter. No confirmed cases of transmitter shedding were observed; 15 of 899 transmitters (2%) that were checked for functionality failed prior to the expected battery expiration. The retention of external T‐bar tags 1 year after release differed depending on whether the tag was placed anterior or posterior to the secondary dorsal fin (anterior, fish length = 420 mm: 73% retention; anterior, fish length = 700 mm: 73%, posterior: 63%) but was <26% after 4 years for both tag positions and fish sizes. Internal anchor tags had an 88% 1‐year retention probability and 81% 4‐year retention probability. Loop tags had the highest 1‐year retention (89%) but after 4 years retention (28–34% depending on agency) was comparable to that of T‐bar tags.ConclusionBetter understanding of tag retention characteristics through long‐term tagging studies such as this can inform study design, be considered in model design, and ultimately improve inferences from mark–recapture studies.

BLE-Based Indoor Localization: Analysis of Some Solutions for Performance Improvement.

This paper addresses indoor localization using an anchor-based system based on Bluetooth Low Energy (BLE) 5.0 technology, adopting the Received Signal Strength Indicator (RSSI) for the distance estimation. Different solutions have been proposed in the scientific literature to improve the performance of this localization technology, but a detailed performance comparison of these solutions is still missing. The aim of this work is to make an experimental analysis combining different solutions for the performance improvement of BLE-based indoor localization, identifying the most effective one. The considered solutions involve different RSSI signals' conditioning, the use of anchor-tag distance estimation techniques, as well as approaches for estimating the unknown tag position. An experimental campaign was executed in a complex indoor environment, characterized by the continuous presence in the movement of working staff and numerous obstacles. The exploitation of multichannel transmission using RSSI signal aggregation techniques showed the greater performance improvement of the localization system, reducing the positioning error (from 1.5 m to about 1 m). The other examined solutions have shown a lesser impact in the performance improvement with a decrease or an increase in the positioning errors, depending on the considered combination of the adopted solutions.

Research on intelligent control and sensor application strategy of motor based on RFID technology

Abstract People widely use permanent magnet brushless DC motors because of their simple structure, high operating efficiency, simple control, and easy maintenance. This paper constructs an EFID sensor network by merging EFID and sensor technologies and then designs the motor’s intelligent control system and strategy around it. In this paper, the SVR-PSO algorithm is used to localize the motor rotor, which nonlinear SVR trains to construct a nonlinear system of equations for calculating the position of the target tag, and then the PSO algorithm is used to seek the position coordinates of the target tag. The fuzzy PID is utilized to control the brushless DC motor, and the integral separation method is adopted to improve the control strategy. The SVR-PSO positioning algorithm and the improved fuzzy PID control strategy are applied and analyzed. For 12 tags to be measured, the positioning accuracy of SVR-PSO has improved by 56.8% compared to that of LANDMARC. Although SVR-PSO’s positioning algorithm is influenced by mutual coupling and multipath effects, the overall accuracy is still superior to that of LANDMARC. Based on the fuzzy PID controller optimized by the integral separation method, the motor rotational speed has a fast response, a small overshoot, and a small fluctuation of rotational speed, and can automatically regulate and restore stability under the situation of a sudden change of load. The motor speed response is fast, the overshoot is small, and the speed fluctuation is small, and the motor speed can be automatically adjusted and stabilized under the sudden load change, which has better dynamic and static performance than the traditional PID controller and fuzzy PID controller. The purpose of this paper is to provide a strategy reference for the use of RFID technology in the intelligent control of motors.

RF-SLAM: UHF-RFID Based Simultaneous Tags Mapping and Robot Localization Algorithm for Smart Warehouse Position Service

In this paper, we propose an RFID based simultaneous localization and mapping (RF-SLAM) method that allows us, for the first time, to estimate the robot's position and the tags' 3D position in the warehouse environment simultaneously without any reference tags and external sensors, using only COTS RFID device. RF-SLAM is designed to transform the RFID measurement into the relative tag position constraint and use a corresponding graph based model to solve the SLAM problem. Specifically, a multi-antenna based relative localization method using phase measurement and odometer data in a short time is proposed as the front end. The back end is a novel graph model based on the relative tags position constraint and odometer constraint. Experiments in different types of warehouses show the localization accuracy of robot and tags' 3D position is about 5cm and 10cm, respectively. The experimental results in a more challenging and actual environment are still competitive.

Research on the optimization of the innovation path of university education and teaching management based on the weighted function algorithm of RFID technology

Abstract College education and teaching management are experiencing a transition from traditional modes to informational modes. This paper constructs a management mode for university teaching informatization based on RFID technology and designs the workflow and functions for RFID. For the positioning of student RFID tags on campus, a time-gap ALOHA algorithm is proposed to reduce the collision rate by dividing the processing time of student tags into several time gaps. After obtaining the student tags, an improved K-weighted center-of-mass localization algorithm is proposed for multi-point localization, which makes the weight of multiple known nodes in the process of operation more reasonably distributed through the setting of the weight size. In the simulation test of campus student localization, when the number of beacon nodes is 40, the average error of the K-weighted prime is 6.5%, 4.25%, and 2.1% lower than that of the prime algorithm, weighted prime, and weighted differential prime, respectively.

Indoor UWB Positioning and Position Tracking Data Set

Indoor positioning has become a hot topic in various fields, such as industry, healthcare, and commerce. Ultra-wideband (UWB) radio technology provides a cost-effective solution for range-based positioning, offering exceptionally high accuracy and precision. Its ultra-high temporal resolution enables range measurements with accuracy of a few centimeters. To develop and evaluate range-based positioning systems, we collected measurements in four different indoor environments using eight fixed devices and one mobile positioning device. To eliminate the fluctuation of walking speed from the data, we pre-defined a path in each indoor environment, similar to the human walking path, which was sampled at equidistant positions. We collected multiple range measurements and channel impulse response (CIR) data at each tag position on the path. The resulting dataset supports the development of range-based positioning and position tracking algorithms with various combinations of network topologies and anchor-tag combinations. We have also provided a full set of data analysis tools that enable the reproducibility of results and serve as a basis for further development of range-based UWB positioning algorithms.

An Indoor Tags Position Perception Method Based on GWO–MLP Algorithm for RFID Robot

This paper proposes a tag position perception method for scenarios such as package retrieval in unmanned warehouses and book management in libraries. This method can accurately predict the distribution of tag space positions in real–time during RFID robot inventory. Firstly, the signal strength (RSSI) and speed of identification (SoI) are used as features. The grey wolf optimization multi–layer perceptron neural network model (GWO–MLP) is employed to predict the distance of tag groups. Secondly, a tag orientation prediction algorithm is designed to estimate the orientation of the tag groups. Finally, the periodicity of the phase is determined by the characteristic of RSSI attenuation as the tag–to–antenna distance increases, solving the problem of position ambiguity caused by phase periodicity. The experiment has shown that this method achieves a high accuracy rate of 96.67% and 97% in predicting the distance and orientation of tag groups, respectively. The average error in distance perception for the single tag is less than 3 cm, enabling precise perception of RFID tag positions. This method facilitates more efficient operation management and accurate item traceability.

A Method of Time-sharing Location for Low-power Tags

In the traditional power equipment positioning system, to achieve tag positioning, the system needs servers, base stations, and tags. To ensure more stability of the system, it needs to range with four base stations during tag positioning. However, the system will have excessive power consumption, and the time to initiate ranging between multiple tags is random, which will cause serious data distortion. Therefore, to adjust the system with complex power equipment management, this paper proposes a low power label time-sharing location method. First, establishing an ultra-wideband UWB between the BTSs to synchronize the time of each BTS. Then, the tag just ranges with one of the BTSs, and the other BTSs get a receiving time. Finally, the time difference method is used to convert the distance between the tag and all other base stations, to reduce the power consumption of the system. The feasibility of the proposed method is verified by an example. This method can effectively solve the problem of multi-label location, which makes the power consumption of label location low and the location will not conflict, and has good engineering practical value.

Self-Supervised Deep Location and Ranging Error Correction for UWB Localization

In this paper, we propose a self-supervised deep network that mainly applies location and ranging error corrections to a classical UWB localization approach to improve its accuracy. The core of this method is the self-supervised learning strategy which removes the requirement for ground-truth in the training process, and thus reduces the training cost of the method. To this end, we first use an existing classical UWB localization approach to provide an initial tag location, and then build a deep location and ranging error correction (DLRC) network to jointly estimate the tag position corrections and distance corrections. The self-supervised training strategy is built based on these regressed corrections and the initial tag position as well as the fixed anchor positions and raw ranging measurements, through the topological structure of the UWB sensors. Finally, the initial tag location can be corrected by the trained DLRC network. For this proposed method, it makes use of high-level representations of the UWB measurements by the deep network, while the geometric information important for UWB localization is also considered though the self-training strategy and the classical approach. Therefore, it can effectively improve the localization performance compared to the stat-of-the-art classical approach. This improvement is also verified by conducting real-world experiments.

Synthesis and biological activity of ganglioside GM3 analogues with a (S)-CHF-Sialoside linkage and an alkyne tag.

The alkyne tag, consisting of only two carbons, is widely used as a bioorthogonal functional group due to its compactness and nonpolar structure, and various probes consisting of lipids bearing an alkyne tag have been developed. Here, we designed and synthesized analogues of ganglioside GM3 bearing an alkyne tag in the fatty acid moiety and evaluated the effect of the alkyne tag on the biological activity. To eliminate the influence of other factors such as degradation of the glycan chain when evaluating biological activity in a cellular environment, we introduced the tag into sialidase-resistant (S)-CHF-linked GM3 analogues developed by our group. The designed analogues were efficiently synthesized by tuning the protecting group of the glucosylsphingosine acceptor. The growth-promoting effect of these analogues on Had-1 cells was dramatically altered depending upon the position of the alkyne tag.

Indoor Localization Method for a Mobile Robot Using LiDAR and a Dual AprilTag

Global localization is one of the important issues for mobile robots to achieve indoor navigation. Nowadays, most mobile robots rely on light detection and ranging (LiDAR) and adaptive Monte Carlo localization (AMCL) to realize their localization and navigation. However, the reliability and performance of global localization only using LiDAR are restricted due to the monotonous sensing feature. This study proposes a global localization approach to improve mobile robot global localization using LiDAR and a dual AprilTag. Firstly, the spatial coordinate system constructed with two neighboring AprilTags is applied as the reference basis for global localization. Then, the robot pose can be estimated by generating precise initial particle distribution for AMCL based on the relative tag positions. Finally, in pose tracking, the count and distribution of AMCL particles, evaluating the certainty of localization, is continuously monitored to update the real-time position of the robot. The contributions of this study are listed as follows. (1) Compared to the localization method only using LiDAR, the proposed method can locate the robot’s position with a few iterations and less computer power consumption. (2) The failure localization issues due to the many similar indoor features can be solved. (3) The error of the global localization can be limited to an acceptable range compared to the result using a single tag.