Selenium (Se) uptake and dynamic changes of Se content in soil–plant systems

Abstract

In this study, we collected crop plants and associated soil samples and determined these for selenium (Se) content to analyze the uptake, enrichment, and translocation of Se in the different soil–plant systems of an agricultural production area, elucidate the dynamic mechanisms relating to Se content in plants and soil during different growth periods, and screen plants for high Se enrichment ability. Bioconcentration factor determinations indicated that the grains of rice have the strongest Se enrichment ability, followed by soybean and corn. Translocation factor analysis indicated that the grains of rice and corn have similar low translocation abilities for Se compared with soybean. Within the study area, the Se content in plants was closely related to the soil available Se content and varied considerably among different growth periods and plant organs. This study provides a theoretical basis for the development and utilization of local agricultural products.

European headache federation guideline on idiopathic intracranial hypertension

Idiopathic Intracranial Hypertension (IIH) is characterized by an elevation of intracranial pressure (ICP no identifiable cause. The aetiology remains largely unknown, however observations made in a number of ...

Characterization of composted sewage sludge during the maturation process: a pilot scale study

Abstract

This paper determines the impact of the maturation process of composted sewage sludge on the quality of the final product and assesses the stabilization effect. The samples of composted sewage sludge were taken from a wastewater treatment plant located in Pomerania in northern Poland. The sewage sludge was composted in an open windrow composting plant with the addition of straw and wood chips in the turning windrow. The aeration of the sewage sludge mixture was conducted based on two methods. The first phase (intensive degradation phase of 6 to 8 weeks) was characterized by frequently turning; the second phase for maturation used aeration channels (2 to 3 months). In three sampling campaigns samples were taken from the same windrow after 2 (no. 1), 8 (no. 2), and 12 weeks (no. 3) of maturation. Fresh samples were used for analyzing the stabilization parameter as static respiration activity (AT₄). Furthermore, the values of pH, organic matter (OM), total organic carbon (TOC), elementary composition, nutrients, total content, and mobile forms of heavy metals were analyzed in the compost samples. A significant decrease was found in the stabilization parameter (AT₄) during the maturation of tested materials. In turn, no significant differences were found in the elementary composition. The concentration of most metals increased in the final product. The total content of heavy metals in the final product did not exceed the limit values for the agricultural use of sewage sludge, compost from municipal waste, and for organic fertilizers. There were no significant changes in the percentage of bioavailable and mobile forms of heavy metals during compost maturation. Zinc was characterized by the highest level of mobile and bioavailable forms, which may cause bioaccumulation after the fertilization of soil. The study has shown that the process of maturation of compost from sewage sludge not affects changes in the content of heavy metal forms. The scope of this study has been planned on a wider scale for different variants of sewage sludge composting, in order to evaluate the process.

Managing Periocular Filler-Related Syndrome Prior to Lower Blepharoplasty

Abstract

Background

Hyaluronic acid (HA) fillers are extensively used in periocular volume augmentation. Although they have an excellent safety profile, filler-related issues such as visibility/palpability, contour abnormalities, malar edema, and blue-gray dyschromia can occur. Recognition and management of filler-related issues are critical prior to subsequent procedures. The clinical course of patients who had periocular HA filler-related issues and subsequently underwent lower eyelid blepharoplasty is described.

Methods

HA filler was dissolved with hyaluronidase (15–30 U/cm²) treatment. Visible lower eyelid fat prolapse after filler removal was corrected with transconjunctival blepharoplasty with fat repositioning and skin resurfacing. Complications and outcome were assessed and recorded.

Results

Twenty-three patients (46 eyelids) were treated. All presented with contour abnormalities, 19 with contour abnormalities and malar edema, and seven with blue-gray dyschromia. In 15 patients, one session of hyaluronidase completely dissolved the filler, and in eight patients, two sessions were required. Of these eight patients, edema resolved after the second hyaluronidase injection in four; in the remaining four, mild edema persisted despite absence of visible/palpable filler. Postblepharoplasty, 19 patients had an acceptable outcome with no complications (82.6%). Four patients had prolonged edema postoperatively; three had a resolution by 6 months. In 23 patients who had skin resurfacing procedures, there was no incidence of postinflammatory hyperpigmentation.

Conclusions

HA filler-related issues need to be identified and managed prior to further intervention. Hyaluronidase treatment effectively dissolves the filler, but mild malar edema can persist. Outcomes are acceptable after subsequent blepharoplasty, but adequate patient counseling is necessary about expectations and limitations.

Level of Evidence IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Refinements in Tear Trough Deformity Correction: Intraoral Release of Tear Trough Ligaments: Anatomical Consideration and Clinical Approach

Abstract

Background

Correction of tear trough (TT) deformity is a crucial aspect of facial rejuvenation. Because the anatomical origins of TT deformity lie in the TT ligaments, which firmly attach the dermis to the periosteum, the release of TT ligaments should be considered when performing an etiological correction. The aim of this paper is to propose an alternative method for TT deformity correction, comprising use of filler together with the release of TT ligaments. This technique was compared to the procedure of only percutaneous filler.

Methods

From January 2014 to December 2015, 10 patients were enrolled in the study for recurrence of TT deformity. All the patients underwent TT ligament release and filler injections; all had been previously treated with percutaneous hyaluronic acid injection without ligament release. Under local anesthesia, the TT ligaments were detached using a blunt cannula introduced directly in the supra periosteal plane through an intraoral access. Once the ligament was released, the TT depression was evenly recontoured with a very small amount of filler. The clinical data, digital images, evaluations of outcomes, including patient satisfaction rates were collected and compared.

Results

Adding the procedure of TT ligament release to filler injections showed satisfactory results, avoiding an unnatural puffy appearance. The comparison between the two different methods showed improved outcomes and increased patient satisfaction with minor patient discomfort among those who underwent TT ligament release.

Conclusion

Because TT ligaments are among the etiologic factors of TT deformity, they have a strong impact on procedures that are designed to improve TT deformity; therefore, TT ligament release should always be considered to obtain satisfactory, natural results.

Level of Evidence IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Studying Controversies: Unification, Contradiction, Integration

Abstract

My aim here is to show that approximate truth as a paraconsistent notion (neutral to the realism/anti-realism debate) can be successfully incorporated into the analysis of scientific unification, thus advancing towards a more realistic representation of theory development that takes into account the controversies that often loom alongside the progress of research programmes. I support my analysis with a case study of the recent debate in ecology centred around the existence of the paradox of enrichment and the controversy between ecological models of predation that employ prey-dependent and ratio-dependent functional responses. These models were initially proposed as equally good representations of the basic aspects of predator–prey dynamics. However, both models generated inconsistent observational consequences and, therefore, introduced a contradiction within predator–prey theory. I argue that by accepting these models as approximately true representations of predator–prey dynamics we can convey how the available observational data have been successfully systematized in a consistent way under them. This first step in resolving the controversy relied on building a series of contrastive arguments based on both models' derivations about population dynamics and the available empirical data. The heightening of this contrast between the models, in turn, was also essential in defining a limiting function which can be used to integrate both models and reach a new unified expression of predator–prey dynamics.

Evaluation of Escherichia coli pathotypes associated with Irritable Bowel Syndrome

Abstract

Irritable Bowel Syndrome (IBS) affects 10–20% of people. Increased numbers of Escherichia coli (E. coli) correlate with symptoms, and patients respond to antimicrobials targeting E. coli. We examined whether specific E. coli strains, phylogroups and pathotypes are associated with IBS. We evaluated 218 E. coli isolates from 33 IBS patients and 23 healthy controls. RAPD analysis revealed 89 E. coli strains (29 controls, 60 IBS), spanning the A, B1, B2, D phylogroups. Strains were similarly enriched in virulence genes associated with extraintestinal pathogenic E.coli (ExPEC) and/or adherent-invasive E.coli (AIEC). Three strains harbored a diarrheagenic virulence gene (2 IBS, 1 control). E. coli capable of invading epithelial cells or replicating in macrophages were detected in 53% of IBS and 50% controls, and 67% IBS and 45% controls respectively (P>0.05). AIEC were identified in 33% of IBS patients vs. 20% of controls (P=0.35). Virulence genes ibeA, ColV and pduC were associated with intramacrophage persistence; ibeA and ColV were associated with epithelial invasion and AIEC pathotype (P<0.05). IBS patients and controls are commonly colonized by E. coli that resemble ExPEC and display pathogen-like behavior in vitro, similar to CD-associated AIEC. The relationship of these resident pathosymbiont E. coli to IBS warrants further investigation.

Quantitative proteomic analysis of xylose fermentation strain Pichia stipitis CBS 5776 to lignocellulosic inhibitors acetic acid, vanillin, and 5-hydroxymethylfurfural

Abstract

To obtain a global insight into the dynamic protein expression pattern in Pichia stipitis during xylose fermentation in the presence of three representative inhibitors (acetic acid, vanillin, and 5-hydroxymethylfurfural), proteins were extracted for quantitative proteomic analysis using 8-plex isobaric tag for relative and absolute quantitation (iTRAQ) on a liquid chromatography-mass/mass spectrometry (LC-MS/MS) instrument. Interestingly, aconitase (Aco1p) and NAD-isocitrate dehydrogenase (Idh1p), were upregulated during the middle exponential phase in the presence of the three inhibitors during tricarboxylic acid (TCA) cycle. We speculated that yeast cells adaptively increased the expression of the TCA cycle proteins to compensate for low NADH derived from glycolysis in the presence of the three inhibitors. Proteins related to amino acid metabolism, aminoacyl tRNA synthesis, and stress response were also significantly affected in the presence of the three inhibitors. Taken together, quantitative proteomic analysis is capable of monitoring P. stipitis xylose fermentation under inhibitor conditions and identifying physiological changes, such as stress response.

Streptomyces protein secretion and its application in biotechnology

Abstract

Bacteria are of tremendous importance in the pharma- and bio-industry as producers of a broad range of economically interesting metabolites and proteins. Gram-positive bacteria are valuable hosts for the production of heterologous proteins for obvious reasons. Contrary to Gram-negative bacteria, Gram-positive bacteria release their secreted proteins immediately into the spent culture broth as they are not hindered by an outer membrane. Secretory protein production also avoids the formation of inclusion bodies, hence facilitating downstream processing. Eight protein secretion pathways have been described in Gram-positive bacteria, but solely the general secretion or Sec pathway, and to a lesser extent, the Twin-arginine pathway are used for the recombinant protein production. This process is not always successful, but might be hampered by inefficient secretion, misfolding of the recombinant protein, its degradation by proteases and metabolic burden by the host hindering proper growth and diminishing product yield. In this review, the different protein export avenues will be briefly discussed, and the potential means to optimize protein secretion and yields for the Streptomyces lividans model presented. The proposed approaches are largely applicable for other Streptomyces host systems.

Extraction of open-state mitral valve geometry from CT volumes

Abstract

Purpose

The importance of mitral valve therapies is rising due to an aging population. Visualization and quantification of the valve anatomy from image acquisitions is an essential component of surgical and interventional planning. The segmentation of the mitral valve from computed tomography (CT) acquisitions is challenging due to high variation in appearance and visibility across subjects. We present a novel semi-automatic approach to segment the open-state valve in 3D CT volumes that combines user-defined landmarks to an initial valve model which is automatically adapted to the image information, even if the image data provide only partial visibility of the valve.

Methods

Context information and automatic view initialization are derived from segmentation of the left heart lumina, which incorporates topological, shape and regional information. The valve model is initialized with user-defined landmarks in views generated from the context segmentation and then adapted to the image data in an active surface approach guided by landmarks derived from sheetness analysis. The resulting model is refined by user landmarks.

Results

For evaluation, three clinicians segmented the open valve in 10 CT volumes of patients with mitral valve insufficiency. Despite notable differences in landmark definition, the resulting valve meshes were overall similar in appearance, with a mean surface distance of \(1.62 \pm 2.10\) mm. Each volume could be segmented in 5–22 min.

Conclusions

Our approach enables an expert user to easily segment the open mitral valve in CT data, even when image noise or low contrast limits the visibility of the valve.

A patient-specific haptic drilling simulator based on virtual reality for dental implant surgery

Abstract

Purpose

In the dental implant surgery, there are inevitable risks due to the anatomically complex operation in the cranio-maxillofacial region. Therefore, there is a trend to use computer-aided technology to simulate the process of the implant surgery. In this study, we present a haptic simulator for trainees to study and rehearse the drilling performance of dental implant surgery.

Materials and methods

The dental implant surgery simulator (DISS) is developed based on the haptic force-feedback device Omega.6, and some free open-source software libraries such as Computer Haptics and Active Interface (CHAI3D), Qt and Visualization Toolkit. To achieve the desired effects of drilling, the meshes are subdivided with a recursive algorithm which breaks down a triangular patch into 4 sub-triangles. The drilling operation can be implemented at any specified location of the model. Once the drilling direction is determined, the position and rotation of the haptic device tool are constrained to the orientation through a dimension reduction algorithm. The driller diameter and drill speed are tunable to implement stepwise drilling for the patient-specific models.

Results

A patient-specific drilling simulator based on virtual reality for dental implant surgery is presented. The simulation of stepwise drilling was conducted, and three patient-specific models reconstructed by Computed Tomography data were employed to help the novices to find the suitable drilling parameter.

Conclusion

The obtained results showed that the haptic-based DISS could simulate various dental implant surgeries with different driller diameter and drill speed which takes patient-specific models as input. The evaluation of the DISS proves its good performance and it could provide an effective method to improve the skills and experiences of trainees.

Accuracy of computer-aided design models of the jaws produced using ultra-low MDCT doses and ASIR and MBIR

Abstract

Purpose

To compare the surface of computer-aided design (CAD) models of the maxilla produced using ultra-low MDCT doses combined with filtered backprojection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) reconstruction techniques with that produced from a standard dose/FBP protocol.

Methods

A cadaveric completely edentulous maxilla was imaged using a standard dose protocol (CTDIvol: 29.4 mGy) and FBP, in addition to 5 low dose test protocols (LD1-5) (CTDIvol: 4.19, 2.64, 0.99, 0.53, and 0.29 mGy) reconstructed with FBP, ASIR 50, ASIR 100, and MBIR. A CAD model from each test protocol was superimposed onto the reference model using the 'Best Fit Alignment' function. Differences between the test and reference models were analyzed as maximum and mean deviations, and root-mean-square of the deviations, and color-coded models were obtained which demonstrated the location, magnitude and direction of the deviations.

Results

Based upon the magnitude, size, and distribution of areas of deviations, CAD models from the following protocols were comparable to the reference model: FBP/LD1; ASIR 50/LD1 and LD2; ASIR 100/LD1, LD2, and LD3; MBIR/LD1. The following protocols demonstrated deviations mostly between 1–2 mm or under 1 mm but over large areas, and so their effect on surgical guide accuracy is questionable: FBP/LD2; MBIR/LD2, LD3, LD4, and LD5. The following protocols demonstrated large deviations over large areas and therefore were not comparable to the reference model: FBP/LD3, LD4, and LD5; ASIR 50/LD3, LD4, and LD5; ASIR 100/LD4, and LD5.

Conclusions

When MDCT is used for CAD models of the jaws, dose reductions of 86% may be possible with FBP, 91% with ASIR 50, and 97% with ASIR 100. Analysis of the stability and accuracy of CAD/CAM surgical guides as directly related to the jaws is needed to confirm the results.

Modular force approximating soft robotic pneumatic actuator

Abstract

Purpose

Soft robots are highly flexible and adaptable instruments that have proven extremely useful, especially in the surgical environment where compliance allows for improved maneuverability throughout the body. Endoscopic devices are a primary example of an instrument that physicians use to navigate to difficult-to-reach areas inside the body. This paper presents a modular soft robotic pneumatic actuator as a proof of concept for a compliant endoscopic device.

Methods

The actuator is 3D printed using an FDM printer. Maximum bending angle is measured using image processing in MATLAB at a gauge pressure level of 35 psi. End-effector displacement is measured using electromagnetic tracking as gauge pressure ranges from 10 to 35 psi, and uniaxial tensile loading ranges from 0 to 120 g.

Results

The actuator achieves a maximum bending angle of 145°. Fourth-order polynomial regression is used to model the actuator displacement upon inflation and tensile loading with an average coefficient of correlation value of 0.998. We also develop a feedforward neural network as a robust computer-assisted method for controlling the actuator that achieves a coefficient of correlation value of 0.996.

Conclusion

We propose a novel modular soft robotic pneumatic actuator that is developed via rapid prototyping and evaluated using image processing and machine learning models. The curled resting shape allows for simple manufacturing and achieves a greater range of bending than other actuators of its kind. A feedforward neural network provides accurate prediction of end-effector displacement upon inflation and loading to deliver precise manipulation and control.

Development of a shoulder-mounted robot for MRI-guided needle placement: phantom study

Abstract

Purpose

This paper presents new quantitative data on a signal-to-noise ratio (SNR) study, distortion study, and targeting accuracy phantom study for our patient-mounted robot (called Arthrobot). Arthrobot was developed as an MRI-guided needle placement device for diagnostic and interventional procedures such as arthrography.

Methods

We present the robot design and inverse kinematics. Quantitative assessment results for SNR and distortion study are also reported. A respiratory motion study was conducted to evaluate the shoulder mounting method. A phantom study was conducted to investigate end-to-end targeting accuracy. Combined error considering targeting accuracy, respiratory motion, and structure deformation is also reported.

Results

The SNR study showed that the SNR changes only 2% when the unpowered robot was placed on top of a standard water phantom. The distortion study showed that the maximum distortion from the ground truth was 2.57%. The average error associated with respiratory motion was 1.32 mm with standard deviation of 1.38 mm. Results of gel phantom targeting studies indicate average needle placement error of 1.64 mm, with a standard deviation of 0.90 mm.

Conclusions

Noise and distortion of the MR images were not significant, and image quality in the presence of the robot was satisfactory for MRI-guided targeting. Combined average total error, adding mounting stability errors and structure deformation errors to targeting error, is estimated to be 3.4 mm with a standard deviation of 1.65 mm. In clinical practice, needle placement accuracy under 5 mm is considered sufficient for successful joint injection during shoulder arthrography. Therefore, for the intended clinical procedure, these results indicate that Arthrobot has sufficient positioning accuracy.

Deep dense multi-path neural network for prostate segmentation in magnetic resonance imaging

Abstract

Purpose

We propose an approach of 3D convolutional neural network to segment the prostate in MR images.

Methods

A 3D deep dense multi-path convolutional neural network that follows the framework of the encoder–decoder design is proposed. The encoder is built based upon densely connected layers that learn the high-level feature representation of the prostate. The decoder interprets the features and predicts the whole prostate volume by utilizing a residual layout and grouped convolution. A set of sub-volumes of MR images, centered at the prostate, is generated and fed into the proposed network for training purpose. The performance of the proposed network is compared to previously reported approaches.

Results

Two independent datasets were employed to assess the proposed network. In quantitative evaluations, the proposed network achieved 95.11 and 89.01 Dice coefficients for the two datasets. The segmentation results were robust to variations in MR images. In comparison experiments, the segmentation performance of the proposed network was comparable to the previously reported approaches. In qualitative evaluations, the segmentation results by the proposed network were well matched to the ground truth provided by human experts.

Conclusions

The proposed network is capable of segmenting the prostate in an accurate and robust manner. This approach can be applied to other types of medical images.

Real-time microrobot posture recognition via biplane X-ray imaging system for external electromagnetic actuation

Abstract

Purpose

As a promising intravascular therapeutic approach for autonomous catheterization, especially for thrombosis treatment, a microrobot or robotic catheter driven by an external electromagnetic actuation system has been recently investigated. However, the three-dimensional (3D) real-time position and orientation tracking of the microrobot remains a challenge for precise feedback control in clinical applications owing to the micro-size of the microrobot geometry in vessels, along with bifurcation and vulnerability. Therefore, in this paper, we propose a 3D posture recognition method for the unmanned microrobotic surgery driven by an external electromagnetic actuator system.

Methods

We propose a real-time position and spatial orientation tracking method for a millimeter-sized intravascular object or microrobot using a principal component analysis algorithm and an X-ray reconstruction. The suggested algorithm was implemented to an actual controllable wireless microrobot system composed of a bullet-shaped object, a biplane X-ray imaging device, and an electromagnetic actuation system. Numerical computations and experiments were conducted for the performance verification.

Results

The experimental results showed a good performance of the implemented system with tracking errors less than 0.4 mm in position and 2° in orientation. The proposed tracking technique accomplished a fast processing time, ~ 0.125 ms/frame, and high-precision recognition of the micro-sized object.

Conclusions

Since the suggested method does not require pre-information of the object geometry in the human body for its 3D shape and position recognition, it could be applied to various elliptical shapes of the microrobot system with computation time efficacy and recognition accuracy. Hence, the method can be used for therapeutic millimeter- or micron-sized manipulator recognition in vascular, as well as implanted objects in the human body.

Development and internal validation of an aneurysm rupture probability model based on patient characteristics and aneurysm location, morphology, and hemodynamics

Abstract

Purpose

Unruptured cerebral aneurysms pose a dilemma for physicians who need to weigh the risk of a devastating subarachnoid hemorrhage against the risk of surgery or endovascular treatment and their complications when deciding on a treatment strategy. A prediction model could potentially support such treatment decisions. The aim of this study was to develop and internally validate a model for aneurysm rupture based on hemodynamic and geometric parameters, aneurysm location, and patient gender and age.

Methods

Cross-sectional data from 1061 patients were used for image-based computational fluid dynamics and shape characterization of 1631 aneurysms for training an aneurysm rupture probability model using logistic group Lasso regression. The model's discrimination and calibration were internally validated based on the area under the curve (AUC) of the receiver operating characteristic and calibration plots.

Results

The final model retained 11 hemodynamic and 12 morphological variables, aneurysm location, as well as patient age and gender. An adverse hemodynamic environment characterized by a higher maximum oscillatory shear index, higher kinetic energy and smaller low shear area as well as a more complex aneurysm shape, male gender and younger age were associated with an increased rupture risk. The corresponding AUC of the model was 0.86 (95% CI [0.85, 0.86], after correction for optimism 0.84).

Conclusion

The model combining variables from various domains was able to discriminate between ruptured and unruptured aneurysms with an AUC of 86%. Internal validation indicated potential for the application of this model in clinical practice after evaluation with longitudinal data.

Semiautomatic neck curve reconstruction for intracranial aneurysm rupture risk assessment based on morphological parameters

Abstract

Purpose

Morphological parameters of intracranial aneurysms (IAs) are well established for rupture risk assessment. However, a manual measurement is error-prone, not reproducible and cumbersome. For an automatic extraction of morphological parameters, a 3D neck curve reconstruction approach to delineate the aneurysm from the parent vessel is required.

Methods

We present a 3D semiautomatic aneurysm neck curve reconstruction for the automatic extraction of morphological parameters which was developed and evaluated with an experienced neuroradiologist. We calculate common parameters from the literature and include two novel angle-based parameters: the characteristic dome point angle and the angle difference of base points.

Results

We applied our method to 100 IAs acquired with rotational angiography in clinical routine. For validation, we compared our approach to manual segmentations yielding highly significant correlations. We analyzed 95 of these datasets regarding rupture state. Statistically significant differences were found in ruptured and unruptured groups for maximum diameter, maximum height, aspect ratio and the characteristic dome point angle. These parameters were also found to statistically significantly correlate with each other.

Conclusions

The new 3D neck curve reconstruction provides robust results for all datasets. The reproducibility depends on the vessel tree centerline and the user input for the initial dome point and parameters characterizing the aneurysm neck region. The characteristic dome point angle as a new metric regarding rupture risk assessment can be extracted. It requires less computational effort than the complete neck curve reconstruction.

Model checking for trigger loss detection during Doppler ultrasound-guided fetal cardiovascular MRI

Abstract

Purpose

Ultrasound (US) is the state of the art in prenatal diagnosis to depict fetal heart diseases. Cardiovascular magnetic resonance imaging (CMRI) has been proposed as a complementary diagnostic tool. Currently, only trigger-based methods allow the temporal and spatial resolutions necessary to depict the heart over time. Of these methods, only Doppler US (DUS)-based triggering is usable with higher field strengths. DUS is sensitive to motion. This may lead to signal and, ultimately, trigger loss. If too many triggers are lost, the image acquisition is stopped, resulting in a failed imaging sequence. Moreover, losing triggers may prolong image acquisition. Hence, if no actual trigger can be found, injected triggers are added to the signal based on the trigger history.

Method

We use model checking, a technique originating from the computer science domain that formally checks if a model satisfies given requirements, to simultaneously model heart and respiratory motion and to decide whether respiration has a prominent effect on the signal. Using bounds on the physiological parameters and their variability, the method detects when changes in the signal are due to respiration. We use this to decide when to inject a trigger.

Results

In a real-world scenario, we can reduce the number of falsely injected triggers by 94% from more than 87% to less than 5%. On a subset of motion that would allow CMRI, the number can be further reduced to below 0.2%. In a study using simulations with a robot, we show that our method works for different types of motions, motion ranges, starting positions and heartbeat traces.

Conclusion

While DUS is a promising approach for fetal CMRI, correct trigger injection is critical. Our model checking method can reduce the number of wrongly injected triggers substantially, providing a key prerequisite for fast and artifact free CMRI.

Priority monism, dependence and fundamentality

Abstract

Priority monism (PM) is roughly the view that the universe is the only fundamental object, that is, a concrete object that does not depend on any other concrete object. Schaffer, the main advocate of PM, claims that PM is compatible with dependence having two different directions: from parts to wholes for subcosmic wholes, and from whole to parts for the cosmic whole. Recently it has been argued that this position is untenable. Given plausible assumptions about dependence, PM entails that dependence has only one direction, it always goes from wholes to parts. One such plausible assumption is a principle of Isolation. I argue that, given all extant accounts of dependence on the market, PM entails No Isolation. The argument depends upon a particular feature of the dependence relation, namely, necessitation and its direction. In the light of this, I contend that the argument is important, insofar as it suggests that we should distinguish dependence from other cognate notions, e.g. grounding. Once this distinction is made, I suggest we should also distinguish between two different notions of fundamentality that might turn out to be not-coextensive.