Passive Marker Research Articles

Robustness verification of active 3D marker in turbid underwater environment and docking experiment in real sea

Aiming at developing underwater battery recharging system, we have been researching on automatic docking of an underwater robot using dual-eyes-based visual servoing and 3D marker without emission of light (passive 3D marker). In our previous researches, we conducted docking experiments in seaarea, having verified the effectiveness in the day time in an environment with less turbid water condition. Given the situation that the docking aims for battery recharging in deep sea bottom, pitch-dark and turbid environment should be considered as inevitable condition. Since lighting passive 3Dmarker from vehicle in turbid water environment results in the images taken by video cameras set on the vehicle being looked wholly white, some new idea seems to be required. Our proposal to overcome this difficulty is to introduce a lighting 3D marker (active 3D marker) that has LEDs inside. Inthis paper, recognition performances using active and passive 3D marker are compared, having confirmed that the new active marker with no-lighting from a vehicle could be recognizable in dark and turbid environment than the passive marker lighted from the vehicle. This has contributed to the actualsea docking in pitch-dark real sea environment.

Host-rock deformation during the emplacement of the Mourne Mountains granite pluton: Insights from the regional fracture pattern

Abstract The Mourne Mountains magmatic center in Northern Ireland consists of five successively intruded granites emplaced in the upper crust. The Mourne granite pluton has classically been viewed as a type locality of a magma body emplaced by cauldron subsidence. Cauldron subsidence makes space for magma through the emplacement of ring dikes and floor subsidence. However, the Mourne granites were more recently re-interpreted as laccoliths and bysmaliths. Laccolith intrusions form by inflation and dome their host rock. Here we perform a detailed study of the deformation in the host rock to the Mourne granite pluton in order to test its emplacement mechanism. We use the host-rock fracture pattern as a passive marker and microstructures in the contact-metamorphic aureole to constrain large-scale magma emplacement-related deformation. The dip and azimuth of the fractures are very consistent on the roof of the intrusion and can be separated into four steeply inclined sets dominantly striking SE, S, NE, and E, which rules out pluton-wide doming. In contrast, fracture orientations in the northeastern wall to the granites suggest shear parallel to the contact. Additionally, contact-metamorphic segregations along the northeastern contact are brecciated. Based on the host-rock fracture pattern, the contact aureole deformation, and the north-eastward–inclined granite-granite contacts, we propose that mechanisms involving either asymmetric “trap-door” floor subsidence or laccolith and bysmalith intrusion along an inclined or curved floor accommodated the emplacement of the granites and led to deflection of the northeastern wall of the intrusion.

Phonological Process in Passive Verb Markers of Bahasa Bakumpai

This research is about the phonological process which occurs in the forming of passive verbs in bahasa Bakumpai. The theory applied in this research is generative phonology. The object of this research is bahasa Bakumpai, one of the languages used by people in South and Central Borneo who live by Barito River. The research was conducted with descriptive qualitative method. The data collection was conducted by searching active and passive verbs in bahasa Bakumpai dictionary and verified by a native speaker. Result of the research shows that the prefix which becomes the passive marker is /i/ and when it is attached to stems begin with consonants, there are insertions of consonants such as the [n], [m], [ng], and [ny] which are categorized as allophones since they occur in complementary distribution in the environments.

Automated alignment detection of an additively manufactured Z-frame marker to process instrument targeting signals in interventional MRI

Abstract MRI-guided interventions (iMRI, e.g. prostate biopsy) are usually performed under a free-hand instrument targeting approach to guide and feed the instrument (e.g. biopsy needle) along the desired trajectory. However, this technique requires many iterative movements either from the interventionist or of the patient (with the MRI table) in and out of the MRI tunnel, which is cumbersome, time-consuming and expensive. To overcome these downsides, interventional MRI procedures can be facilitated with remotely controllable assistance systems for instrument alignment. Such systems require an accurate registration and tracking of the position and orientation of the instrument. Passive fiducial marker frames (e.g. additively manufactured Z-frame marker) are capable of providing full information about a device´s orientation within the image. In this paper, we present an automated alignment detection algorithm to track a Z-marker from system-independent screen-captured images. We evaluated the precision of the detection algorithm by analysing its computation results from schematic gold standard images in different marker orientations in comparison to MR-images with the same orientations. Our combined setup consists of a precise alignment system, an additively manufactured Z-frame marker and the related detection algorithm. It offers a fast, simple, independent and accurate automated instrument targeting for iMRI. For future work, we plan to conduct phantom targeting tests in combination with robotic alignment systems.

Geochemistry constrains global hydrology on Early Mars

Ancient hydrology is recorded by sedimentary rocks on Mars. The most voluminous sedimentary rocks that formed during Mars' Hesperian period are sulfate-rich rocks, explored by the Opportunity rover from 2004–2012 and soon to be investigated by the Curiosity rover at Gale crater. A leading hypothesis for the origin of these sulfates is that the cations were derived from evaporation of deep-sourced groundwater, as part of a global circulation of groundwater. Global groundwater circulation would imply sustained warm Earthlike conditions on Early Mars. Global circulation of groundwater including infiltration of water initially in equilibrium with Mars' CO2 atmosphere implies subsurface formation of carbonate. We find that the CO2 sequestration implied by the global groundwater hypothesis for the origin of sulfate-rich rocks on Mars is 30–5000 bars if the Opportunity data are representative of Hesperian sulfate-rich rocks, which is so large that (even accounting for volcanic outgassing) it would bury the atmosphere. This disfavors the hypothesis that the cations for Mars' Hesperian sulfates were derived from upwelling of deep-sourced groundwater. If, instead, Hesperian sulfate-rich rocks are approximated as pure Mg-sulfate (no Fe), then the CO2 sequestration is 0.3–400 bars. The low end of this range is consistent with the hypothesis that the cations for Mars' Hesperian sulfates were derived from upwelling of deep-sourced groundwater. In both cases, carbon sequestration by global groundwater circulation actively works to terminate surface habitability, rather than being a passive marker of warm Earthlike conditions. Curiosity will soon be in a position to discriminate between these two hypotheses. Our work links Mars sulfate cation composition, carbon isotopes, and climate change.

Systemic sclerosis medications and risk of scleroderma renal crisis

BackgroundScleroderma Renal Crisis (SRC) is associated with significant morbidity and mortality. While prednisone is strongly associated with SRC, there are no previous large cohort studies that have evaluated ace inhibitor (ACEi) calcium channel blocker (CCB), angiotensin receptor blocker (ARB), endothelin receptor blocker (ERB), non-steroidal anti-inflammatory drug (NSAID), fluticasone, or mycophenolate mofetil (MMF) use in systemic sclerosis (SSc) and the risk of SRC.MethodsIn this retrospective cohort study of the entire military electronic medical record between 2005 and 2016, we compared the use of ACEi, ARB, CCB, NSAID, ERB, fluticasone, and MMF after SSc diagnosis for 31 cases who subsequently developed SRC to 322 SSc without SRC disease controls.ResultsACEi was associated with an increased risk for SRC adjusted for age, race, and prednisone use [odds ratio (OR) 4.1, 95% confidence interval (CI) 1.6–10.2, P = 0.003]. On stratified analyses, ACEi was only associated with SRC in the presence [OR 5.3, 95% CI 1.1–29.2, p = 0.03], and not the absence of proteinuria. In addition, a doubling of ACEi dose [61% vs. 12%, p < 0.001) and achieving maximum ACEi dose [45% vs. 4%, p < 0.001] after SSc diagnosis was associated with future SRC. CCB, ARB, NSAIDs, ERB, fluticasone, and MMF use were not significantly associated with SRC.ConclusionACEi use at SSC diagnosis was associated with an increased risk for SRC. Results suggest that it may be a passive marker of known SRC risk factors, such as proteinuria, or evolving disease. SSC patients that require ACEi should be more closely monitored for SRC.

GantryMate: A Modular MR-Compatible Assistance System for MR-Guided Needle Interventions.

Percutaneous minimally invasive interventions are difficult to perform in closed-bore high-field magnetic resonance systems owing to the limited space between magnet and patient. To enable magnetic resonance–guided needle interventions, we combine a small, patient-mounted assistance system with a real-time instrument tracking sequence based on a phase-only cross-correlation algorithm for marker detection. The assistance system uses 2 movable plates to align an external passive marker with the anatomical target structure. The targeting accuracy is measured in phantom experiments, yielding a precision of 1.7 ± 1.0 mm for target depths up to 38 ± 13 mm. In in vivo experiments, the possibility to track and target static and moving structures is demonstrated.

Ultrasound-Assisted Guidance With Force Cues for Intravascular Interventions

Image guidance during minimally invasive intravascular interventions is primarily achieved based on X-ray fluoroscopy, which has several limitations including limited 3-D imaging capability, significant doses of radiation to operators, and lack of contact force measurement between the cardiovascular tissue and interventional tools. Ultrasound imaging can be adopted to complement or possibly replace 2-D fluoroscopy for intravascular interventions due to its portability, safety to use, and the ability of providing depth information. However, it is challenging to precisely visualize catheters and guidewires in the ultrasound images. In this paper, we propose a novel method to figure out both the position and orientation of the catheter tip in 2-D ultrasound images in real time by detecting and tracking a passive marker attached to the catheter tip. Moreover, the contact force can be estimated simultaneously as well via measuring the length variation of the marker. A geometrical model-based method is introduced to detect the initial position of the marker, and a Kanade–Lucas–Tomasi-based algorithm is developed to track the position, orientation, and length of the marker. The ex vivo experiment results validate the effectiveness of the proposed approach in automatically locating the catheter tip in ultrasound images and its capability of sensing the contact force. Therefore, it can be concluded that the presented method can be utilized to better facilitate operators during intravascular interventions. Note to Practitioners —This paper is motivated by the vision-based force sensing mechanism. A coil spring marker is used to visualize and locate the catheter tip in ultrasound images. The metallic helical structure of the marker can result in remarkable features in 2-D in-plane ultrasound images. A geometrical model-based detection algorithm is proposed to detect the passive marker in initial frame regardless of its length and orientation variation. A prediction–detection-combined tracking algorithm is developed to automatically track the catheter tip for the subsequent frames in real time. Most importantly, the distal force can be simultaneously estimated due to the length variation of the passive marker. The sensed force can be fed back to a robotic catheterization system during intravascular interventions.

Passive underwater acoustic tags using layered media.

Autonomous Underwater Vehicle (AUV) navigation requires accurate positioning information from the environment. Existing underwater navigation paradigms employ active acoustic transponders that assist in this task, but these more complex and costly systems require maintenance and power. This paper presents instead a passive underwater marker made of different horizontally stacked acoustically reflective materials that is cost effective and relatively simple to service. A marker's characteristic acoustic signature can be detected by AUVs as acoustic backscattering upon tag insonification, and hence be used for navigation purposes.

Detection and Elimination of Signal Errors Due to Unintentional Movements in Biomedical Magnetic Induction Tomography Spectroscopy (MITS).

In biomedical MITS, slight unintentional movements of the patient during measurement can contaminate the aimed images to a great extent. This study deals with measurement optimization in biomedical MITS through the detection of these unpredictable movements during measurement and the elimination of the resulting movement artefacts in the images to be reconstructed after measurement. The proposed detection and elimination (D&E) methodology requires marking the surface of the object under investigation with specific electromagnetically perturbing markers during multi-frame measurements. In addition to the active marker concept already published, a new much simpler passive marker concept is presented. Besides the biological signal caused by the object, the markers will perturb the primary magnetic field inducing their own signals. The markers' signals will be used for the detection of any unwanted object movements and the signal frames corrupted thereby. The corrupted signal frames will be then excluded from image reconstruction in order to prevent any movement artefacts from being imaged with the object. In order to assess the feasibility of the developed D&E technique, different experiments followed by image reconstruction and quantitative analysis were performed. Hereof, target movements were provoked during multifrequency, multiframe measurements in the β-dispersion frequency range on a saline phantom of physiological conductivity. The phantom was marked during measurement with either a small single-turn coil, an active marker, or a small soft-ferrite plate, a passive marker. After measurement, the erroneous phantom signals were corrected according to the suggested D&E strategy, and images of the phantom before and after correction were reconstructed. The corrected signals and images were then compared to the erroneous ones on the one hand, and to other true ones gained from reference measurements wherein no target movements were provoked on the other hand. The obtained qualitative and quantitative measurement and image reconstruction results showed that the erroneous phantom signals could be accurately corrected, and the movement artefacts could be totally eliminated, verifying the applicability of the novel D&E technique in measurement optimization in biomedical MITS and supporting the proposed aspects.

The Use of the Passive Marker bei in Spoken Mandarin

The passive marker bei has been the subject of a significant quantity of linguistic research; however the bulk of studies to date have focussed on its use in written Chinese. This article provides a snap shot of current usage of bei in spoken Mandarin based on a corpus of Chinese chat show transcripts and assesses the claims made about the bei construction in the literature. Careful examination of the data reveals that this grammatical marker is both less sensitive to a number of constraints outlined in the mainstream literature and, at the same time, more responsive to a range of different contextual factors, some of which seem to have been overlooked in previous treatments of Mandarin grammar. In particular, it is found that many non-grammatical factors play a role in determining the behaviour of the passive marker bei. The analysis demonstrates that spoken data can reveal interesting insights in to the complexity of the grammatical system, insights that may possibly not be so readily apparent on the basis of written texts and grammaticality judgments alone. This suggests that other morpho-syntactic features of Modern Standard Chinese could likewise benefit from a detailed analysis of their behaviour in spoken interactions.

The neuter in Manda, with a focus on its reinterpretation as passive

This study accounts for the neuter extension -ɪk in Manda (N11), a Bantu language spoken along Lake Nyasa (Lake Malawi) in southern Tanzania. The article offers a description of both the formal and functional features of this morpheme in Manda, while paying special attention to its rare extended function as a proper passive marker licensing an explicit prototypical agent. Based on comparative data from Manda’s neighbouring languages, it is argued that this special functional feature of the neuter in Manda reflects a broader characteristic of this Bantu-speaking area, where a reflex of the passive marker reconstructed for Proto-Bantu has been lost or is restricted in use. This fact has, in turn, paved the way for innovations with regard to the expression of passive voice, of which the use of the neuter suffix is one of several possible strategies. Considering comparative data, this study also attempts to reconstruct the pathway of change leading to the neuter acquiring a passive function. The hypothesis put forward suggests that the passive function of the neuter stems from incremental steps of expansion, which eventually enabled it to co-occur with prototypical agents.

On the origins of passive allomorphy in Cuwabo (Bantu P34)

Cuwabo has two different derivational suffixes to form passive verb stems, i.e. -iw and -uw. Unlike in many other Bantu languages, these suffixes are not phonologically conditioned allomorphs of one single morphological passive marker. They are interchangeable as productive passive markers, but -uw has a broader functional range than -iw. The suffix -uw actually is a ‘quasi-middle’ marker as defined by Dom et al.: it semantically focuses the activity expressed by the verb on one single argument, and it syntactically signals the intransitivity of a given verb stem. In this article, it is shown that -uw in Cuwabo is the regular reflex of the Proto-Bantu intransitive separative suffix *-ʊk whose semi-productive intransitivising function as part of a causative/anticausative alternation was functionally broadened to productive passivisation leading to competition with -iw, the inherited reflex of the Proto-Bantu passive suffix *-ibʊ.

Simultaneous slice excitation for accelerated passive marker tracking via phase-only cross correlation (POCC) in MR-guided needle interventions.

Toaccelerate a passive tracking sequence based on phase-only cross correlation (POCC) using simultaneous slice excitation. For magnetic resonance (MR)-guided biopsy procedures, passive markers have been proposed that can be automatically localized online using a POCC-based tracking sequence. To accelerate the sequence, a phase-offset multiplanar (POMP) excitation technique was implemented to acquire tracking images. In a phantom experiment, the POMP-POCC sequence was tested and compared with the sequential non-accelerated version in terms of duration and accuracy. Further, technical feasibility of thePOMP-POCC sequence was tested in a patient undergoing a prostate biopsy. The temporal resolution of the POMP-POCC tracking sequence is accelerated by 33% compared with the sequential approach. In phantom experiments, the POMP-POCC and sequential sequences yielded the same targeting accuracy of 1.6 ± 0.7mm. Technical proof of concept of the new sequence could be demonstrated in a successful in vivo prostate biopsy. POMP-POCC tracking can substantially reduce the duration of localization of passive markers in MR-guided needle interventions without compromising targeting accuracy.

A marker-based contactless catheter-sensing method to detect surgeons' operations for catheterization training systems.

It is challenging to position a catheter or a guidewire within a patient's complicated and delicate vascular structure due to the lack of intuitive visual feedback by only manipulating the proximal part of the surgical instruments. Training is therefore critical before an actual surgery because any mistake due to the surgeon's inexperience can be fatal for the patient. The catheter manipulation skills of experienced surgeons can be useful as input for training novice surgeons. However, few research groups focused on designs with consideration of the contactless catheter motion measurement, which allows obtaining expert surgeons' catheter manipulation trajectories whilst still allowing them to employ an actual catheter and apply conventional pull, push and twist of the catheter as used in bedside intravascular interventional surgeries. In this paper, a novel contactless catheter-sensing method is proposed to measure the catheter motions by detecting and tracking a passive marker with four feature-point groups. The passive marker is designed to allow simultaneously sensing the translational and rotational motions of the input catheter. Finally, the effectiveness of the proposed contactless catheter-sensing method is validated by conducting a series of comparison experiments. The accuracy and error analysis are quantified based on the absolute error, relative error, mean absolute error, and the success rate of the detection.

Abstract 4172: Radiation-induced blood-tumor barrier permeability in a preclinical model of lung cancer brain metastasis

Abstract BACKGROUND: Lung cancer has the highest mortality rate among all cancers and accounts for over half of newly diagnosed brain metastases each year. Standard therapeutic advancements are prolonging lives of lung cancer patients with each new approved formulation, however patients with brain metastases have limited options and no curative measures currently exist. Current treatment modalities for brain metastases from primary lung cancer include differing methodologies of radiotherapy (whole brain radiotherapy and/or stereotactic radiosurgery), systemic chemotherapies, and neurosurgery. Radiation in many cases is not ablative, but palliative. Herein we demonstrate the ability of radiotherapy to influence blood-tumor barrier permeability in a novel preclinical model of lung cancer brain metastasis. METHODS: Athymic female nude mice were intracardially injected with our novel PC-9-BR brain specific lung cancer cell line. Tumors were allowed to develop and monitored using bioluminescent imaging. Using the Xstrahl XenX small animal irradiator, we were able to deliver 26 Gy to the right hemisphere of the immobilized mouse. 4 hours post radiotherapy, mice were perfused with the passive permeability marker Oregon Green, followed by an indocyanine green (bound to albumin) washout to infer vascular space. Brains were then extracted, snap frozen in isopentane (-50°C), and sliced to 20μm. Florescence was quantified using a MVX microscope and cellsense software. RESULTS: Analysis of irradiated brain regions demonstrated statistically significant more accumulation of the passive permeability marker, Oregon Green, compared to the contralateral hemisphere. CONCLUSIONS: Radiation induced permeability was witness in mice after a single dose of 26 Gy when compared to non-irradiated tumor tissue 4 hours post treatment. FURTURE DIRECTIVES: Experiments utilizing ionizing radiation to simulate treatment of CNS metastases could reveal better adjunctive chemotherapeutic regimens and or provide insight to the mechanism underlying this enhanced permeability. Citation Format: Samuel A. Sprowls, Neal Shah, Afroz S. Mohammad, Marc Pinti, Rachel M. Tallman, Devin U. John, Paul R. Lockman. Radiation-induced blood-tumor barrier permeability in a preclinical model of lung cancer brain metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4172.

The development of the English-type passive in Balinese

The morpheme -a in Balinese is ambiguous between the third person enclitic pronoun and a passive voice marker. Different views exist as to whether the morpheme can be the pronoun in the presence of a teken agentive phrase. This paper argues that it can and that the construction in which the pronoun -a and a teken phrase co-occur (the hybrid type) is an instance of clitic doubling. A hypothesis is proposed about how the third person pronoun changed into a passive marker and how different passive subtypes came into existence. It is claimed that the hybrid type played a key role in the change. The hybrid type supports the analysis of passives in general as a clitic doubling construction (Baker, Johnson and Roberts 1989). A clitic doubling analysis of passives enables a new typology of passives whereby passives are classified according to how the clitic and its double in a passive clause are expressed.

The Formation of the Copula Function of Wei 为 and the Nature of the “Wei 为 V” Construction

This paper aims to explain the development of the copula function of wei 为and to show that wei in the “wei V” construction is a copula during pre-Han times, rather than a passive marker. Therefore, in essence, the “wei V” construction is a copula construction rather than a passive construction. In this analysis, we pay special attention to the “yi 以X wei 为Y” construction and draw the following conclusions: (1) the generalized copula function of wei derives from the “yi X wei Y” construction because of the disposal function of yi, and because wei absorbed the characteristics of the “yi X wei Y” construction. This conclusion is based on the observation that the unique features of wei as a copula are congruent with its function in the “yi X wei Y” construction, and that the change from “V yi wei” to “V wei” indicates that wei replaced “yi wei” to a certain degree. (2) “X wei V” is an alternative pattern of “yi X wei V” when a causer (C) does not appear in the same clause with wei. These observations are supported by the fact that “yi X wei V” and “X wei V” have the same (low) frequency, and are both very limited in their semantic range, and that their exchangeability does not have any influence on their semantics. (3) “Wei A V” is formed through the omission of yi in the “yi X wei A V” or, alternatively, through the addition of the agent A in “wei V”, whereas “wei A (zhi) suo V” is the consequence of “A (zhi) suo V” replacing “A V” in “wei A V”. Therefore, none of the wei constructions in pre-Qin should be regarded as syntactically functioning as passive constructions. Rather, “wei A suo V” became a common passive construction only in the Han Dynasty.

On the structure and interpretation of Polish passives

The realization of Polish passives is influenced by the specific properties that a given participle shares with its verbal base. These include: argument structure and aspectual type, the conjugation class and the phonological properties of the stem. This paper offers an account of how these variables are reflected in the exponence and morphophonology of Polish passives. The paper presents an analysis of the distribution of Passive Participle Markers -l- /ɫ/, -t- /t/, -n- /n/ and -on- /ɔn/ in Polish within a syntactic approach to word formation (Jablonska 2004; Caha 2009, Embick & Marantz 2008). I also address the issue of the morphophonological mutations attested in Polish passive participles and postulate that they should not be given a uniform analysis. The alternation between /ɛ/ and /a/ attested in Polish ej- and e-verbs is suppletive in nature, while mutations attested in the thematic marker -ną-~-nie- /nɔ/~/ɲɛ/ and the Passive Participle Marker -on-~-eni- /ɔn/~/ɛɲ/ are triggered by the integration...

Passive underwater acoustic markers using Bragg backscattering.

This letter demonstrates the feasibility of a passive underwater acoustic marker technology (or "AcoustiCode") for use in underwater navigation. An AcoustiCode tag is a planar surface with machined periodic patterns capable of producing Bragg backscattering beampatterns with engineered spatial and frequency variations, thus having a unique three-dimensional acoustic signature over a selected frequency band. Hence, these AcoustiCodes enable three-dimensional navigation and information signaling in a totally passive manner for existing high-frequency SONAR systems (potentially mounted on autonomous underwater vehicles), which naturally operate in a narrow frequency band and can also be used over significantly longer ranges compared to optically-based systems.