Development of a third-generation biosensor to determine sterigmatocystin mycotoxin: An early warning system to detect aflatoxin B1

A third-generation enzymatic biosensor was developed to quantify sterigmatocystin (STEH). It was based on a glassy carbon electrode modified with a composite of the soybean peroxidase enzyme (SPE) and chemically reduced graphene oxide. The optimal conditions to construct the biosensor were obtained through an experimental design based on the response surfaces methodology. The experiments were performed in 0.1 mol L-1 phosphate buffer solution, pH 5. Amperometric measurements were carried out at - 0.09 V vs Ag/AgCl (3 mol L-1 NaCl). The biosensor showed a lineal response in the concentration range from 6.9 × 10-9 to 5.0 × 10-7 mol L-1. The limit of detection was 2.3 × 10-9 mol L-1 for a signal: noise ratio of 3: 1. Values of the apparent Michaellis-Menten constant, KMapp, obtained by using both Lineweaver-Burk and Eadi-Hofstee methods were (1.5 ± 0.2) × 10-6 and (1.2 ± 0.2) × 10-6 mol L-1, respectively. STEH was analyzed in corn samples spiked with STEH, with an average recovery of 96.5%. The biosensor was also used to determine STEH in corn samples inoculated with the Aspergillus flavus fungus, which is an aflatoxins producer. Considering that STEH is a precursor of aflatoxin B1 (AFB1) in its biological transformation, its decrease over time was related to the production of AFB1. The STEH concentration determined using the biosensor was in very good agreement with that determined by HPLC.

Gingival Health of Porcelain Laminate Veneered Teeth: A Retrospective Assessment

STATEMENT OF PROBLEM

The long-term effect of the presence of porcelain laminate veneers (PLVs) on the health of the surrounding gingival issues is not available in the restorative literature.

PURPOSE

To assess the long-term effect of PLVs on the health of the surrounding gingival tissues. A secondary aim was to correlate gingival crevicular fluid (GCF) scores with clinical parameters used for gingival health assessment in teeth treated with PLVs.

METHODS AND MATERIALS

Patients who received PLVs placed at the Graduate Restorative Clinic within a seven- to 14-year period were recalled for clinical evaluations. Periodontal measurements including gingival index (GI), periodontal pocket depth (PPD), gingival recession (GR), and clinical attachment level (CAL) were measured using a standard probe and indices. Gingival Crevicular Fluid (GCF) was measured with a Periotron machine (Periotron 8000, Oraflow Inc), using Periopaper (Periopaper Gingival Fluid Collection Strip, Oraflow Inc.) for fluid collection. Photographs of any observed clinical defect were taken. Data were tabulated using Excel 2010 (Microsoft Corp). Statistical analysis for all descriptive statistics was performed using SPSS 21 (SPSS Software, IBM Corp.) and Stata SE 13 (Stata Software, StataCorp). Repeated-measures analysis of variance (ANOVA) was done to test for statistical significance of the mean pocket depths between the restored and unrestored surfaces of the veneered teeth. The significance level for all tests was p<0.05. Pearson's correlation coefficient was performed for testing statistical significance between GCF and GI and between GCF and PPD.

RESULTS

The frequency distribution of the GI included 47 PLVs (43%) with normal gingiva, 16 (15%) with mild inflammation, and 46 (42%) with moderate inflammation and bleeding on probing. The average PPD on the facial surface of the maxillary and mandibular PLVs was 2.17 mm and 2.16 mm, respectively. On the lingual surface, the average PPD was 2.10 mm for maxillary and 2.22 mm for mandibular PLVs. Gingival recession was seen in 27% of the evaluated PLVs. The repeated-measures ANOVA revealed p≥0.136, showing no statistical difference in the mean pocket depths between restored facial and unrestored lingual surfaces of the veneered teeth. A moderate correlation (r=0.407) was found between GCF and GI, which was significant at p<0.001. No correlation (r=0.124) was found between GCF and PPD, which was not significant at p=0.197.

CONCLUSIONS

Gingival response to the evaluated PLVs was in the satisfactory range, with overall GI scores ranging between normal and moderate inflammation, pocket depths ranging from 1 to 2 mm, and recession present in 27% of the evaluated PLVs. No statistically significant difference was found between the mean pocket depths of the restored and unrestored surfaces of veneered teeth (p≥0.136). A moderate correlation was found between GCF and GI.

Relationship between FFR, CFR and coronary microvascular resistance - Practical implications for FFR-guided percutaneous coronary intervention

Objective

The aim was threefold: 1) expound the independent physiological parameters that drive FFR, 2) elucidate contradictory conclusions between fractional flow reserve (FFR) and coronary flow reserve (CFR), and 3) highlight the need of both FFR and CFR in clinical decision making. Simple explicit theoretical models were supported by coronary data analyzed retrospectively.

Methodology

FFR was expressed as a function of pressure loss coefficient, aortic pressure and hyperemic coronary microvascular resistance. The FFR-CFR relationship was also demonstrated mathematically and was shown to be exclusively dependent upon the coronary microvascular resistances. The equations were validated in a first series of 199 lesions whose pressures and distal velocities were monitored. A second dataset of 75 lesions with pre- and post-PCI measures of FFR and CFR was also analyzed to investigate the clinical impact of our hemodynamic reasoning.

Results

Hyperemic coronary microvascular resistance and pressure loss coefficient had comparable impacts (45% and 49%) on FFR. There was a good concordance (y = 0.96 x − 0.02, r² = 0.97) between measured CFR and CFR predicted by FFR and coronary resistances. In patients with CFR < 2 and CFR/FFR ≥ 2, post-PCI CFR was significantly >2 (p < 0.001), whereas it was not (p = 0.94) in patients with CFR < 2 and CFR/FFR < 2.

Conclusion

The FFR behavior and FFR-CFR relationship are predictable from basic hemodynamics. Conflicting conclusions between FFR and CFR are explained from coronary vascular resistances. As confirmed by our results, FFR and CFR are complementary; they could jointly contribute to better PCI guidance through the CFR-to-FFR ratio in patients with coronary artery disease.

Meshfree simulations of ultrasound vector flow imaging using smoothed particle hydrodynamics

Before embarking on a series of in vivo tests, design of ultrasound-flow-imaging modalities are generally more efficient through computational models as multiple configurations can be tested methodically. To that end, simulation models must generate realistic blood flow dynamics and Doppler signals. The current in silico ultrasound simulation techniques suffer mainly from uncertainty in providing accurate trajectories of moving ultrasound scatterers. In mesh-based Eulerian methods, numerical truncation errors from the interpolated velocities, both in the time and space dimensions, can accumulate significantly and make the pathlines unreliable. These errors can distort beam-to-beam inter-correlation present in ultrasound flow imaging. It is thus a technical issue to model a correct motion of the scatterers by considering their interaction with boundaries and neighboring scatterers. We hypothesized that in silico analysis of emerging ultrasonic imaging modalities can be implemented more accurately with meshfree approaches. We developed an original fluid-ultrasound simulation environment based on a meshfree Lagrangian CFD (computational fluid dynamics) formulation, which allows analysis of ultrasound flow imaging. This simulator combines smoothed particle hydrodynamics (SPH) and Fourier-domain linear acoustics (SIMUS  =  simulator for ultrasound imaging). With such a particle-based computation, the fluid particles also acted as individual ultrasound scatterers, resulting in a direct and physically sound fluid-ultrasonic coupling. We used the in-house algorithms for fluid and ultrasound simulations to simulate high-frame-rate vector flow imaging. The potential of the particle-based method was tested in 2D simulations of vector Doppler for the intracarotid flow. The Doppler-based velocity fields were compared with those issued from SPH. The numerical evaluations showed that the vector flow fields obtained by vector Doppler components were in good agreement with the original SPH velocities, with relative errors less than 10% and 2% in the cross-beam and axial directions, respectively. Our results showed that SPH-SIMUS coupling enables direct and realistic simulations of ultrasound flow imaging. The proposed coupled algorithm has also the advantage to be 3D compatible and parallelizable.

The UPF1 interactome reveals interaction networks between RNA degradation and translation repression factors in Arabidopsis

The RNA helicase UP-FRAMESHIFT (UPF1) is a key factor of nonsense-mediated decay (NMD), a mRNA decay pathway involved in RNA quality control and in the fine-tuning of gene expression. UPF1 recruits UPF2 and UPF3 to constitute the NMD core complex, which is conserved across eukaryotes. No other components of UPF1-containing ribonucleoproteins (RNPs) are known in plants, despite its key role in regulating gene expression. Here, we report the identification of a large set of proteins that co-purify with the Arabidopsis UPF1, either in an RNA-dependent or RNA-independent manner. We found that like UPF1, several of its co-purifying proteins have a dual localization in the cytosol and in P-bodies, which are dynamic structures formed by the condensation of translationally repressed mRNPs. Interestingly, more than half of the proteins of the UPF1 interactome also co-purify with DCP5, a conserved translation repressor also involved in P-body formation. We identified a terminal nucleotidyltransferase, ribonucleases and several RNA helicases among the most significantly enriched proteins co-purifying with both UPF1 and DCP5. Among these, RNA helicases are the homologs of DDX6/Dhh1, known as translation repressors in humans and yeast, respectively. Overall, this study reports a large set of proteins associated with the Arabidopsis UPF1 and DCP5, two components of P-bodies, and reveals an extensive interaction network between RNA degradation and translation repression factors. Using this resource, we identified five hitherto unknown components of P-bodies in plants, pointing out the value of this dataset for the identification of proteins potentially involved in translation repression and/or RNA degradation.

A Dual Tissue-Doppler Optical-Flow Method for Speckle Tracking Echocardiography at High Frame Rate

A coupled computational method for recovering tissue velocity vector fields from high-frame-rate echocardiography is described. Conventional transthoracic echocardiography provides limited temporal resolution, which may prevent accurate estimation of the 2-D myocardial velocity field dynamics. High-frame-rate compound echocardiography using diverging waves with integrated motion compensation has been shown to provide concurrent high-resolution B-mode and tissue Doppler imaging (TDI). In this paper, we propose a regularized least-squares method to provide accurate myocardial velocities at high frame rates. The velocity vector field was formulated as the minimizer of a cost function that is a weighted sum of: 1) the ${\ell }^{{2}}$ -norm of the material derivative of the B-mode images (optical flow); 2) the ${\ell }^{{2}}$ -norm of the tissue-Doppler residuals; and 3) a quadratic regularizer that imposes spatial smoothness and well-posedness. A finite difference discretization of the continuous problem was adopted, leading to a sparse linear system. The proposed framework was validated in vitro on a rotating disk with speeds up to 20 cm/s, and compared with speckle tracking echocardiography (STE) by block matching. It was also validated in vivo against TDI and STE in a cross-validation strategy involving parasternal long axis and apical three-chamber views. The proposed method based on the combination of optical flow and tissue Doppler led to more accurate time-resolved velocity vector fields.

High-Frame-Rate Speckle-Tracking Echocardiography

Conventional echocardiography is the leading modality for noninvasive cardiac imaging. It has been recently illustrated that high-frame-rate echocardiography using diverging waves could improve cardiac assessment. The spatial resolution and contrast associated with this method are commonly improved by coherent compounding of steered beams. However, owing to fast tissue velocities in the myocardium, the summation process of successive diverging waves can lead to destructive interferences if motion compensation (MoCo) is not considered. Coherent compounding methods based on MoCo have demonstrated their potential to provide high-contrast B-mode cardiac images. Ultrafast speckle-tracking echocardiography (STE) based on common speckle-tracking algorithms could substantially benefit from this original approach. In this paper, we applied STE on high-frame-rate B-mode images obtained with a specific MoCo technique to quantify the 2-D motion and tissue velocities of the left ventricle. The method was first validated in vitro and then evaluated in vivo in the four-chamber view of 10 volunteers. High-contrast high-resolution B-mode images were constructed at 500 frames/s. The sequences were generated with a Verasonics scanner and a 2.5-MHz phased array. The 2-D motion was estimated with standard cross correlation combined with three different subpixel adjustment techniques. The estimated in vitro velocity vectors derived from STE were consistent with the expected values, with normalized errors ranging from 4% to 12% in the radial direction and from 10% to 20% in the cross-range direction. Global longitudinal strain of the left ventricle was also obtained from STE in 10 subjects and compared to the results provided by a clinical scanner: group means were not statistically different ( value = 0.33). The in vitro and in vivo results showed that MoCo enables preservation of the myocardial speckles and in turn allows high-frame-rate STE.

Cross-border collaboration for improved tuberculosis prevention and care: policies, tools and experiences

As tuberculosis (TB) spreads beyond borders with people movements, several interventions ensuring the continuity of care are essential, although difficult to put in place in the absence of well-defined agreements allowing data sharing and easy referral of patients to appropriate health facilities. This article first sets out general principles for cross-border collaboration and continuity of care. It then presents a series of case studies. Policies and practices on cross-border collaboration in selected low-incidence countries (Australia, Italy, Norway, The Netherlands, the United Kingdom and the United States) are described and critically appraised. Details of the World Health Organization's (WHO's) European Respiratory Society TB Consilium for transborder migration and those of the Health Network's TBNet activities are described. With increasing population movement, including migrants and travellers, it is time to build on good practices and existing tools and to remove legal, financial and social barriers to ensure early diagnosis, full treatment and continuity of care across our world. Data sharing between the sending and the receiving countries is of utmost importance and must be conducted in line with privacy protection rules. Successful implementation of these interventions is key to being on track with the WHO's End TB strategy targets for 2030.

Accuracy of speckle tracking in the context of stress echocardiography in short axis view: An in vitro validation study

Aim

This study aimed to test the accuracy of a speckle tracking algorithm to assess myocardial deformation in a large range of heart rates and strain magnitudes compared to sonomicrometry.

Methods and results

Using a tissue-mimicking phantom with cyclic radial deformation, radial strain derived from speckle tracking (RS-SpT) of the upper segment was assessed in short axis view by conventional echocardiography (Vivid q, GE) and post-processed with clinical software (EchoPAC, GE). RS-SpT was compared with radial strain measured simultaneously by sonomicrometers (RS-SN). Radial strain was assessed with increasing deformation rates (60 to 160 beats/min) and increasing pulsed volumes (50 to 100 ml/beat) to simulate physiological changes occurring during stress echocardiography. There was a significant correlation (R² = 0.978, P <0.001) and a close agreement (bias ± 2SD, 0.39 ± 1.5%) between RS-SpT and RS-SN. For low strain values (<15%), speckle tracking showed a small but significant overestimation of radial strain compared to sonomicrometers. Two-way analysis of variance did not show any significant effect of the deformation rate. For RS-SpT, the feasibility was excellent and the intra- and inter-observer variability were low (the intraclass correlation coefficients were 0.96 and 0.97, respectively).

Conclusions

Speckle tracking demonstrated a good correlation with sonomicrometry for the assessment of radial strain independently of the heart rate and strain magnitude in a physiological range of values. Though speckle tracking seems to be a reliable and reproducible technique to assess myocardial deformation variations during stress echocardiography, further studies are mandated to analyze the impact of angulated and artefactual out-of-plane motions and inter-vendor variability.

CColor and Vector Flow Imaging in Parallel Ultrasound with Sub-Nyquist Sampling

RF acquisition with a high-performance multi-chan-nel ultrasound system generates massive datasets in short periods of time, especially in "ultrafast" ultrasound when digital receive beamforming is required. Sampling at a rate four times the carrier frequency is the standard procedure since this rule complies with the Nyquist-Shannon sampling theorem and simplifies quadrature sampling. Bandpass sampling (or undersampling) outputs a band-pass signal at a rate lower than the maximal frequency without harmful aliasing. Advantages over Nyquist sampling are reduced storage volumes and data workflow, and simplified digital signal processing tasks. We used RF undersampling in color flow imag-ing (CFI) and vector flow imaging (VFI) to decrease data volume significantly (factor of 3 to 13 in our configurations). CFI and VFI with Nyquist and sub-Nyquist samplings were compared in vitro and in vivo. The estimate errors due to undersampling were small or marginal, which illustrates that Doppler and vector Doppler im-ages can be correctly computed with a drastically reduced amount of RF samples. Undersampling can be a method of choice in CFI and VFI to avoid information overload and reduce data transfer and storage.

Trans-species synthetic gene design allows resistance pyramiding and broad-spectrum engineering of virus resistance in plants

To infect plants, viruses rely heavily on their host's machinery. Plant genetic resistances based on host factor modifications can be found among existing natural variability and are widely used for some but not all crops. While biotechnology can supply for the lack of natural resistance alleles, new strategies need to be developed to increase resistance spectra and durability without impairing plant development. Here, we assess how the targeted allele modification of the Arabidopsis thaliana translation initiation factor eIF4E1 can lead to broad and efficient resistance to the major group of potyviruses. A synthetic Arabidopsis thaliana eIF4E1 allele was designed by introducing multiple amino acid changes associated with resistance to potyvirus in naturally occurring Pisum sativum alleles. This new allele encodes a functional protein while maintaining plant resistance to a potyvirus isolate that usually hijacks eIF4E1. Due to its biological functionality, this synthetic allele allows, at no developmental cost, the pyramiding of resistances to potyviruses that selectively use the two major translation initiation factors, eIF4E1 or its isoform eIFiso4E. Moreover, this combination extends the resistance spectrum to potyvirus isolates for which no efficient resistance has so far been found, including resistance-breaking isolates and an unrelated virus belonging to the Luteoviridae family. This study is a proof-of-concept for the efficiency of gene engineering combined with knowledge of natural variation to generate trans-species virus resistance at no developmental cost to the plant. This has implications for breeding of crops with broad-spectrum and high durability resistance using recent genome editing techniques.

Structural heart disease as the cause of syncope

We described the clinical evolution of patients with structural heart disease presenting at the emergency room with syncope. Patients were stratified according to their syncope etiology and available scores for syncope prognostication. Cox proportional hazard models were used to investigate the relationship between etiology of the syncope and event-free survival. Of the 82,678 emergency visits during the study period, 160 (0.16%) patients were there due to syncope, having a previous diagnosis of structural heart disease. During the median follow-up of 33.8±13.8 months, mean age at the qualifying syncope event was 68.3 years and 40.6% of patients were male. Syncope was vasovagal in 32%, cardiogenic in 57%, orthostatic hypotension in 6%, and of unknown causes in 5% of patients. The primary composite endpoint death, readmission, and emergency visit in 30 days was 39.4% in vasovagal syncope and 60.6% cardiogenic syncope (P<0.001). Primary endpoint-free survival was lower for patients with cardiogenic syncope (HR=2.97, 95%CI=1.94-4.55; P<0.001). The scores were analyzed for diagnostic performance with area under the curve (AUC) and did not help differentiate patients with an increased risk of adverse events. The differential diagnosis of syncope causes in patients with structural heart disease is important, because vasovagal and postural hypotension have better survival and less probability of emergency room or hospital readmission. The available scores are not reliable tools for prognosis in this specific patient population.

Protocol for Robust In Vivo Measurements of Erythrocyte Aggregation Using Ultrasound Spectroscopy

Erythrocyte aggregation is a non-specific marker of acute and chronic inflammation. Although it is usual to evaluate this phenomenon from blood samples analyzed in laboratory instruments, in vivo real-time assessment of aggregation is possible with spectral ultrasound techniques. However, variable blood flow can affect the interpretation of acoustic measures. Therefore, flow standardization is required. Two techniques of flow standardization were evaluated with porcine and equine blood samples in Couette flow. These techniques consisted in either stopping the flow or reducing it. Then, the sensibility and repeatability of the retained method were evaluated in 11 human volunteers. We observed that stopping the flow compromised interpretation and repeatability. Conversely, maintaining a low flow provided repeatable measures and could distinguish between normal and high extents of erythrocyte aggregation. Agreement was observed between in vivo and ex vivo measures of the phenomenon (R² = 82.7%, p value < 0.0001). These results support the feasibility of assessing in vivo erythrocyte aggregation in humans by quantitative ultrasound means.

High-Quality Plane Wave Compounding Using Convolutional Neural Networks

Single plane wave (PW) imaging produces ultrasound images of poor quality at high frame rates (ultrafast). High-quality PW imaging usually relies on the coherent compounding of several successive steered emissions (typically more than ten), which in turn results in a decreased frame rate. We propose a new strategy to reduce the number of emitted PWs by learning a compounding operation from data, i.e., by training a convolutional neural network to reconstruct high-quality images using a small number of transmissions. We present experimental evidence that this approach is promising, as we were able to produce high-quality images from only three PWs, competing in terms of contrast ratio and lateral resolution with the standard compounding of 31 PWs ( 10× speedup factor).

Effect of Light-Curing Exposure Time, Shade, and Thickness on the Depth of Cure of Bulk Fill Composites

Purpose:

To investigate the effect of different light exposure times, shades, and thicknesses on the depth of cure (DOC) of bulk fill composites.

Methods and Materials:

Two bulk fill composites, Tetric EvoCeram Bulk Fill (TBF) and Sonic Fill (SF), and a conventional composite, Filtek Supreme Ultra (FSU), were evaluated. Samples (n=10) were made using two different shades (light and dark), thicknesses (2 and 4 mm) and exposure times (20 and 40 seconds). A Tukon 2100B-testing machine was used to obtain three Knoop hardness numbers (KHNs) measured at the top and bottom of each sample, and DOC was calculated as the bottom/top ratio. Statistical analysis was done using a Student t-test for comparisons between groups with a Bonferroni correction of p &lt; 0.004.

Results:

Top hardness values ranged from 79.79 to 85.07 for FSU, 69.49 to 91.65 for SF, and 51.01 to 57.82 for TBF. Bottom KHNs ranged from 23.54 to 73.25 for FSU, 45.74 to 77.12 for SF, and 36.95 to 52.51 for TBF. TBF had the lowest overall KHNs. Light-curing exposure time, shade, and material thickness influenced the DOC in most groups, especially at 4-mm depths. A higher bottom/top ratio was achieved when a 40-second cure was compared to a 20-second cure, when light shades were compared to dark shades, and when 2-mm increments were compared to 4-mm increments.

Association of body weight with efficacy and safety outcomes in phase III randomized controlled trials of direct oral anticoagulants: a systematic review and meta-analysis

Essentials The association of body weight and patient-important outcomes remains unknown. Phase III randomized controlled trials of direct oral anticoagulants (DOACs) were searched. Risk of outcomes varying among body weight subgroups is not attributable to anticoagulant type. Dose adjustment of DOACs, outside that recommended, is unlikely to improve the outcomes. Click to hear Dr Braunwald's perspective on antithrombotic therapy in cardiovascular disease SUMMARY: Background Concerns have arisen in direct oral anticoagulant (DOAC)-treated patients about safety and efficacy in extremes of body weight. The aims of this systematic review were to investigate the association of body weight and patient-important outcomes in patients treated with DOACs or warfarin, and to demonstrate the fixed-dose effect of DOACs. Methods MEDLINE and EMBASE were searched until November 2016. Phase III randomized controlled trials (RCTs) using DOACs in atrial fibrillation (AF) and acute venous thromboembolism (VTE) were included. Relative risk and 95% confidence interval were calculated. The pooled estimates were performed using a Mantel-Haenszel random effects model. Results A total of 11 phase III RCTs were included. Low body weight was associated with increased risk of thromboembolism compared with non-low body weight (relative risk [RR], 1.57; 95% confidence interval [CI], 1.34-1.85). High body weight was not associated with risk of thromboembolism compared with non-high body weight (RR, 0.88; 95% CI, 0.63-1.23). The subgroup of AF patients with high body weight had a lower risk of thromboembolism compared with non-high body weight (RR, 0.43; 95% CI, 0.28-0.67). Bleeding outcomes were comparable for all body weight comparisons. There were no clear interactions between types of anticoagulant in all outcomes. Conclusion The pooled effect of both the DOAC and comparison arms was likely to be attributable to differences in baseline thrombotic risk in each body weight category, rather than an effect of the type or dose of DOAC used for each indication. Dose adjustment of DOACs, outside that recommended in the package insert, is unlikely to improve safety or efficacy.