Combining range-general and range-specific techniques for late-time focused image reconstructiona).

Synthetic aperture sonar (SAS) is an acoustic method for detecting objects in an environment. Conventional SAS image reconstruction techniques invert a forward model based on geometric scattering and straight-line propagation. Acoustic features that do not fit this model, such as multiple scattering and late-time returns, appear out of focus. This paper describes an image reconstruction technique that selectively applies range-general and range-specific methods to improve the focus of late-time returns while maintaining image quality away from the focal plane. The technique is demonstrated on experimental data and compared with a range-specific algorithm.

Approximate extraction of late-time returns via morphological component analysis.

A fundamental challenge in acoustic data processing is to separate a measured time series into relevant phenomenological components. A given measurement is typically assumed to be an additive mixture of myriad signals plus noise whose separation forms an ill-posed inverse problem. In the setting of sensing elastic objects using active sonar, we wish to separate the early-time return from the object's geometry from late-time returns caused by elastic or compressional wave coupling. Under the framework of morphological component analysis (MCA), we compare two separation models using the short-duration and long-duration responses as a proxy for early-time and late-time returns. Results are computed for a broadside response using Stanton's elastic cylinder model as well as on experimental data taken from an in-air circular synthetic aperture sonar system, whose separated time series are formed into imagery. We find that MCA can be used to separate early and late-time responses in both the analytic and experimental cases without the use of time-gating. The separation process is demonstrated to be compatible with image reconstruction. The best separation results are obtained with a flexible, but computationally intensive, frame based signal model, while a faster Fourier transform based method is shown to have competitive performance.

Late return focusing algorithm for circular synthetic aperture sonar data.

Synthetic aperture sonar processing is used to generate imagery for remote sensing applications such as environmental characterization and object detection. Images primarily represent the initial geometric response of acoustic scattering, but there are additional information embedded in the raw data that are not well-represented in images. For example, responses such as internal multiple scattering or elastic scattering are delayed in time, and they appear defocused in imagery. A complementary processing algorithm is presented that improves the focus of late acoustic scattering responses, which can potentially provide additional information about the object and aid data interpretability.

Measurements and models of the correlation of redundant spatial coherence measurements for the incoherently scattered field.

Sonar systems that exploit correlation for navigation, such as correlation velocity logs and micronavigation for synthetic aperture sonar, often make redundant estimates of the spatial coherence of the scattered field at several spatial lags. Two models for the correlation of these redundant measurements are described. First, an analytical model is derived using the assumption of stationary Gaussian statistics. Next, a numerical model is described that accounts for non-stationary processes present in measurements of seafloor scattering. These models are compared to normal-incidence scattering data collected at Seneca Lake, NY. Both models show good agreement with the measurements when the spatial separation between redundant hydrophone pairs is less than the coherence length. At greater spatial separation, the analytical model diverges from the measurements. This disagreement is explained by a lack of stationarity in the measured data which is captured by the numerical model. Finally, spatial variations in the volume scattering strength of the sediment are identified as a source of the non-stationarity in the measurements.

Measurements of two-dimensional spatial coherence of normal-incidence seafloor scattering.

Measurements have been made near normal incidence of the two-dimensional spatial coherence of the acoustic field scattered from the lakebed in Seneca Lake, New York. In the test region, the lakebed consists of a series of sediment layers created by a sequence of distinct depositional processes. The spatial coherence length of the scattered field is shown to be dependent on the structure of the underlying sediment sequences. Significant ping-to-ping variability in the spatial coherence surface was also observed for each sediment sequence. This variability is quantified by a two-dimensional spatial coherence metric that measures the coherence lengths and asymmetric coherence surface orientation. The ping-to-ping variation of the surface asymmetry appears to be linked to the spatial isotropy of the sediment scattering strength. The scattering strength of the deepest observed sequence in the sub-bottom is the most spatially isotropic and the ping-to-ping variability of the coherence lengths and surface orientations are random. The scattering strength of the shallower sequences is spatially anisotropic and the coherence lengths and surface orientations show intervals of non-random ping-to-ping behavior.

A metric for characterization of two-dimensional spatial coherence.

A metric is developed providing a quantitative measure of the two-dimensional spatial coherence of scattered fields. The metric is based on fitting a function similar to bivariate Gaussian to measured two-dimensional coherence surfaces. This function provides a robust fit to the measured data for a range of coherence lengths and surface asymmetries. Through an eigendecomposition of the bivariate Gaussian covariance matrix, it is possible to define surface orientation as well as coherence lengths along the major and minor axes. The metric is applied to normal-incidence scattering data collected in recent field trials at Seneca Lake, NY.

A point-based scattering model for the incoherent component of the scattered field.

A numerical model for calculation of the incoherent component of the field scattered from random rough surfaces is described. This model is based on the point scattering approach, where the mean scatterer amplitudes are calculated from deterministic models. These amplitudes are then scaled by a complex circular Gaussian random variable to simulate scattering from a surface with minimal coherence length. The resulting simulated fields are shown to agree with theory for the mean field, mean square field, statistical distribution, and the spatial coherence length.

Validation of NOViSE.

The goal of this study was to establish face, content, and construct validity of NOViSE-the first force-feedback enabled virtual reality (VR) simulator for natural orifice transluminal endoscopic surgery (NOTES). Fourteen surgeons and surgical trainees performed 3 simulated hybrid transgastric cholecystectomies using a flexible endoscope on NOViSE. Four of them were classified as "NOTES experts" who had independently performed 10 or more simulated or human NOTES procedures. Seven participants were classified as "Novices" and 3 as "Gastroenterologists" with no or minimal NOTES experience. A standardized 5-point Likert-type scale questionnaire was administered to assess the face and content validity. NOViSE showed good overall face and content validity. In 14 out of 15 statements pertaining to face validity (graphical appearance, endoscope and tissue behavior, overall realism), ≥50% of responses were "agree" or "strongly agree." In terms of content validity, 85.7% of participants agreed or strongly agreed that NOViSE is a useful training tool for NOTES and 71.4% that they would recommend it to others. Construct validity was established by comparing a number of performance metrics such as task completion times, path lengths, applied forces, and so on. NOViSE demonstrated early signs of construct validity. Experts were faster and used a shorter endoscopic path length than novices in all but one task. The results indicate that NOViSE authentically recreates a transgastric hybrid cholecystectomy and sets promising foundations for the further development of a VR training curriculum for NOTES without compromising patient safety or requiring expensive animal facilities.

NMR characterization of novel pyranoanthocyanins derived from the pulp of Panax quinquefolius L. (North American ginseng).

Three major pigments (one natural and two derived) were determined to be present in the berry pulp of Panax quinquefolius L. (North American ginseng). The first was a simple anthocyanin (pelargonidin 3-O-lathyroside) along with two novel pyranoanthocyanins, structurally similar to those recently discovered in Staghorn sumac. The three anthocyanins were structurally characterized using NMR (1 H, gCOSY, gHSQC, gHMBC, TOCSY, ROESY, and 13 C DEPTq135) and High Resolution MS. All three anthocyanins had the disaccharide lathyrose (2-O-(ß-D-xylopyranosyl)-ß-D-galactopyranoside) attached at the 3-O position. In the tradition of naming novel anthocyanin aglycones based on botanical origin, the new pyranoanthocyanin aglycones have been given the common names Panaxidin A (pelaragonidin-4-vinylcatechol) and Panaxidin B (pelargonidin-4-vinylphenol). Copyright © 2015 Her Majesty the Queen in Right of Canada Magnetic Resonance in Chemistry © 2015 John Wiley & Sons, Ltd.

Soybean seeds overexpressing asparaginase exhibit reduced nitrogen concentration.

In soybean seed, a correlation has been observed between the concentration of free asparagine at mid-maturation and protein concentration at maturity. In this study, a Phaseolus vulgaris K+ -dependent asparaginase cDNA, PvAspG2, was expressed in transgenic soybean under the control of the embryo specific promoter of the ß-subunit of ß-conglycinin. Three lines were isolated having high expression of the transgene at the transcript, protein and enzyme activity levels at mid-maturation, with a 20- to 40-fold higher asparaginase activity in embryo than a control line expressing ß-glucuronidase. Increased asparaginase activity was associated with a reduction in free asparagine levels as a percentage of total free amino acids, by 11-18%, and an increase in free aspartic acid levels, by 25-60%. Two of the lines had reduced nitrogen concentration in mature seed as determined by nitrogen analysis, by 9-13%. Their levels of extractible globulins were reduced by 11-30%. This was accompanied by an increase in oil concentration, by 5-8%. The lack of change in nitrogen concentration in the third transgenic line was correlated with an increase in free glutamic acid levels by approximately 40% at mid-maturation.

Seed orientation and magnetic field strength have more influence on tomato seed performance than relative humidity and duration of exposure to non-uniform static magnetic fields.

Different factors (e.g., light, humidity, and temperature) including exposure to static magnetic fields (SMFs), referred here as critical factors, can significantly affect horticultural seed performance. However, the link between magnetic field parameters and other interdependent factors affecting seed viability is unclear. The importance of these critical factors affecting tomato (Solanum lycopersicum L.) var. MST/32 seed performance was assessed after performing several treatments based on a L9 (3(4)) (four factors at three levels) orthogonal array (OA) design. The variable factors in the design were magnetic flux density (R1=332.1±37.8mT; R2=108.7±26.9mT; and R3=50.6±10.5mT), exposure time (1, 2, and 24h), seed orientation (North polarity, South polarity, and control - no magnetic field), and relative humidity (RH) (7.0, 25.5, and 75.5%). After seed moisture content stabilisation at the different chosen RH, seeds were exposed in dark under laboratory conditions to several treatments based on the OA design before performance evaluation. Treatments not employing magnetic field exposure were used as controls. Results indicate that electrolyte leakage rate was reduced by a factor of 1.62 times during seed imbibition when non-uniform SMFs were employed. Higher germination (∼11.0%) was observed in magnetically-exposed seeds than in non-exposed ones, although seedlings emerging from SMF treatments did not show a consistent increase in biomass accumulation. The respective influence of the four critical factors tested on seed performance was ranked (in decreasing order) as seed orientation to external magnetic fields, magnetic field strength, RH, and exposure time. This study suggests a significant effect of non-uniform SMFs on seed performance with respect to RH, and more pronounced effects are observed during seed imbibition rather than during later developmental stages.

Coloring genetically modified soybean grains with anthocyanins by suppression of the proanthocyanidin genes ANR1 and ANR2.

Detection and quantification of the levels of adventitious presence of genetically modified (GM) soybeans in non-GM grain shipments currently requires sophisticated tests that can have issues with their reproducibility. We show here that pigment biosynthesis in the soybean seed coat can be manipulated to provide a distinct color that would enable the simple visible detection of the GM soybean grain. We observed that a distinct red-brown grain color could be engineered by the simultaneous suppression of two proanthocyanidin (PA) genes, ANTHOCYANIDIN REDUCTASE1 (ANR1) and ANR2. Multiple reaction monitoring by liquid chromatography tandem mass spectrometry was used to quantify differentially accumulated seed coat metabolites, and revealed the redirection of metabolic flux into the anthocyanin pigment pathway and unexpectedly the flavonol-3-O-glucoside pathway. The upregulations of anthocyanin isogenes (DFR1 and GST26) and the anthocyanin/flavonol-3-O-glycosyltransferase (UGT78K2) were identified by quantitative RT-PCR to be endogenous feedback and feedforward responses to overaccumulation of upstream flavonoid intermediates resulting from ANR1 and ANR2 suppressions. These results suggested the transcription of flavonoid genes to be a key component of the mechanism responsible for the redirection of metabolite flux. This report identifies the suppression of PA genes to be a novel approach for engineering pigmentation in soybean grains.

Probing nitrobenzhydrol uncaging mechanisms using FerriCast.

The FerriCast derivative FC-NDBF was synthesized from 3-methyl-2-nitrodibenzofuran (NDBF). The photochemistry of the target Fe(3+) photocage and several related congeners provides mechanistic insight into the uncaging quantum yields of nitrobenzhydrol-derived ligands.

Impact of established skills in open surgery on the proficiency gain process for laparoscopic surgery.

BACKGROUND: Laparoscopic training traditionally follows open surgical training. This study aimed to investigate the impact of experience in open surgery on the laparoscopic proficiency gain process. METHODS: A survey form investigating the importance of open experience before the start of laparoscopic training was sent to surgical experts and trainees in the United Kingdom. A separate experimental study objectively assessed the effects of open experience on laparoscopic skill acquisition using a virtual reality simulator. In the study, 11 medical students with no prior surgical experience (group A) and 14 surgical trainees with open but no laparoscopic experience in (group B) performed 250 simulated laparoscopic cholecystectomies. Psychomotor skills were evaluated by motion analysis and video-based global rating scores. Before the first and after the fifth and tenth operation, knowledge of laparoscopic techniques was assessed by a written test and by self-reported confidence levels indicated on a questionnaire. RESULTS: The 80 experts and 282 trainees who responded to the survey believed prior open experience aids confidence levels, knowledge, and skills acquisition. In the simulation study, no intergroup difference was found for any parameter after the first procedure. Group B scored significantly higher in the laparoscopic knowledge test before training began (42.7% vs. 64.3%; p = 0.002), but no significant difference was found after five operations. The two groups did not differ significantly in terms of confidence. Group B had a significantly shorter total operation time only at the first operation (2,305.6 s vs. 1,884.6 s; p = 0.037). No significant intergroup difference in path length, number of movements, or video-based global rating scores was observed. CONCLUSIONS: Prior open experience does not aid the laparoscopic learning process, as demonstrated in a simulated setting. Given the wealth of evidence demonstrating translation of virtual skills to the operating theater, we propose that the safe and effective introduction of well-supervised laparoscopic training may be possible at the beginning of a surgical training curriculum.

Micropropagation of ornamental Prunus spp. and GF305 peach, a Prunus viral indicator.

A micropropagation approach was developed for nine ornamental Prunus species, P. americana, P. cistena, P. glandulosa, P. serrulata 'Kwanzan', P. laurocerasus, P. sargentii, P. tomentosa, P. triloba, P. virginiana 'Schubert', commercially important in North America, and GF305 peach, commonly used for Prunus virus indexing. The micropropagation cycle based on proliferation of vegetative tissues includes establishment of tissue culture through introduction of shoot meristems in vitro, shoot proliferation, root induction and plant acclimatization steps and can be completed in 5 months. A meristem sterilization protocol minimized bacterial and fungal contamination. Multiple shoot formation in ornamental Prunus was obtained through the use of 1 mg l(-1) 6-benzyladenine. For GF305 peach, alteration in the sugar composition, fructose instead of sucrose, and addition of 1 mg l(-1 )ferulic acid had a significant impact on the shoot proliferation rate and maintenance of long-term in vitro culture. Rooting and plant acclimatization conditions were improved using a two-step protocol with a 4-day root induction in indole-3-butiric acid (IBA)-containing media with consequent 3-week root elongation in IBA-free media. One-month incubation of rooted shoots in a vermiculite-based medium resulted in additional shoot and root growth and provided better acclimatization and plant recovery. The micropropagation approach can be used for maintenance of the clonal properties for Prunus spp. as well as a protocol to support meristem therapy against viral infection.

Percutaneous coronary interventions in a rural hospital without surgical backup: report of one year of experience.

This paper demonstrates that percutaneous coronary intervention (PCI) can be provided in a rural setting with results that are at least as good as the national average without untoward risk to the patient. Percutaneous coronary intervention is the initial treatment of choice for acute myocardial infarction (AMI). Historically, PCI has been available in metropolitan areas, yet 20% of the population lives in rural areas. Rural patients with AMI may not be receiving optimal care, especially if PCI is not readily available. In a rural setting, door-to-balloon time for patients with acute ST-elevation MI was 67.66 +/- 30.80 min. This is significantly better than the 186 min reported in the National Registry Myocardial Infarction (NRMI). These results were achieved with a complication rate that was not significantly different from national averages. This study demonstrates that PCI can be provided safely and with good results in a rural setting.

Transfection of Arabidopsis protoplasts with a Plum pox virus (PPV) infectious clone for studying early molecular events associated with PPV infection.

The development of novel strategies against plant viral diseases relies on a better understanding of molecular virus-host interactions. Here, we report an easy, efficient and reproducible protocol for Arabidopsis protoplast isolation and transfection to study the infection and replication of a potyvirus, Plum pox virus (PPV). Macerozyme and cellulose were used to release protoplasts from Arabidopsis leaf tissues, and polyethylene glycol-mediated DNA uptake was employed for transfection of a PPV infectious clone. Protoplast viability was monitored by fluorescein diacetate staining, and transfection efficiency was estimated by transient expression of the green fluorescent protein. The protocol allowed production of 95% viable mesophyll protoplasts and a successful transfection rate of 35%. The system was used further in a time-course experiment to investigate PPV viral RNA accumulation. It was found that 3 h post-transfection (hpt) in the transfected protoplasts viral RNA increased by about 150-fold and progressively accumulated to reach the maximum at 12 hpt. Viral RNA then decreased dramatically at 24 hpt reaching 40% of its peak level. Considering the availability of the whole genome microarrays, and other genomic resources of Arabidopsis, the synchronized single-cell (protoplast) infection system will be useful for elucidating early molecular events associated with PPV infection.

High efficiency plant production of North American ginseng via somatic embryogenesis from cotyledon explants.

An efficient in vitro protocol for plant production of North American ginseng has been established. The pretreatment of cotyledon explants with 1.0 M sucrose at 4 degrees C resulted in an improvement of embryo quality and, combined with a higher sucrose content (7%) in induction medium, improved the embryogenesis frequency from 40% to 75% and the number of embryos per explant from 10 to 21. The frequency of secondary embryogenesis from somatic embryo-derived tissues cultured on MS medium with 1.0 mg l(-1) 2, 4-D and 1.0 mg l(-1) NAA is up to 90%. Somatic embryos can further develop to maturity on SH medium supplemented with 1% activated charcoal and half of them can germinate. About 85% of the germinated embryos will convert into plants with well-developed taproot systems on 1/2 SH medium with 0.5% activated charcoal. The growth chamber and field establishment rates were 95.6 and 93.7%, respectively. The plants transplanted to growth chambers and field plots appear normal.