Variation in second order lateral root length (A) and number (B) in response to virus and nitrogen treatments at the onset of storage root initiation in ‘Beauregard’ sweetpotato.

<p>Treatment legend: + N  =  nitrogen provided as KNO₃, - N = no nitrogen provided. V0  =  plants derived from non-inoculated, virus-tested plant stock; V1  =  plants derived from V0 plant stock graft inoculated with the potyvirus complex (SPFMV, SPVG, SPVC, and SPV2); V2  =  plants derived from plant stock infected with SPCSV. Root length and number were transformed using log 10 and square root transformation, respectively, and Fisher's LSD test at the 0.05 probability level was used to test for statistical significance. The data are expressed as means ± SE from non-transformed data.</p

Virus symptoms on ‘Beauregard’ sweetpotato leaves the day before the first experiment was terminated.

<p>All expanded leaves originating from nodes above the substrate surface are depicted with the bottom leaf in each column being the oldest and the top being the youngest. + N  =  nitrogen provided as KNO₃, - N = no nitrogen provided. V0  =  plants derived from non-inoculated, virus-tested plant stock; V1  =  plants derived from V0 plant stock graft inoculated with the potyvirus complex (SPFMV, SPVG, SPVC, and SPV2); V2  =  plants derived from plant stock infected with SPCSV. Potyvirus symptoms consist of purple ring spots (PRS, see arrow) and purple vein banding (PVB arrow). <i>Sweet potato chlorotic stunt virus</i> symptoms include deep interveinal purpling (IVP circle) that is distinguished from the natural purple cast (NPC circle) that develops on some sweetpotato leaves in that with IVP veins remain green, and the pigmentation is deeper.</p

Representative adventitious roots from sweetpotato ‘Beauregard’ plants subjected to different virus treatments and grown with or without nitrogen.

<p>+ N  =  nitrogen provided as KNO₃, - N = no nitrogen provided. V0  =  plants derived from non-inoculated, virus-tested plant stock; V1  =  plants derived from V0 plant stock graft inoculated with the potyvirus complex (SPFMV, SPVG, SPVC, and SPV2); V2  =  plants derived from plant stock infected with SPCSV. SR = localized swelling indicative of successful storage root initiation. Scale bar  = 5 cm.</p

Variation in adventitious root number (A), first order lateral root length (B), first order lateral root number (C), and lateral root density (D) in response to virus and nitrogen treatments at the onset of storage root initiation in ‘Beauregard’ sweetpotato.

<p>+ N  =  nitrogen provided as KNO₃, - N = no nitrogen provided. V0  =  plants derived from non-inoculated, virus-tested plant stock; V1  =  plants derived from V0 plant stock graft inoculated with the potyvirus complex (SPFMV, SPVG, SPVC, and SPV2); V2  =  plants derived from plant stock infected with SPCSV. Root length and number were transformed using log 10 and square root transformation, respectively, and Fisher's LSD test at the 0.05 probability level was used to test for statistical significance. The data are expressed as means ± SE from non-transformed data.</p

Virus symptom severity ratings of plants from the first (A) and second (B) experiments.

<p>Virus symptom severity was assessed the day before each experiment was terminated by rating each leaf by visual estimation of the proportion of the leaf showing symptoms using a 0 to 3 scale in which: 0 =  no symptoms, 1 = <1/3 of the leaf involved, 2 = 1/3–2/3 of leaf area involved, and 3 = >2/3 of the leaf involved. + N  =  nitrogen provided as KNO₃, - N = no nitrogen provided. V0  =  plants derived from non-inoculated, virus-tested plant stock; V1  =  plants derived from V0 plant stock graft inoculated with the potyvirus complex (SPFMV, SPVG, SPVC, and SPV2); V2  =  plants derived from plant stock infected with SPCSV. Severity ratings were transformed using log 10 and Fisher's LSD test at the 0.05 probability level was used to test for statistical significance. The data are expressed as means ± SE from non-transformed data.</p

Comparison of fitted parameters from the two-stage ASL model in tumour tissue and contralateral healthy gray matter.

<p>Box and whisker plots of mean fitted values of (A) cerebral blood flow (CBF), (B) pre-capillary blood volume (f_pc), (C) pre-capillary transit time (pcTT) and (D) bolus arrival time at the capillaries (BAT_c). Data are shown for healthy tissue and tumor regions in all patients, with horizontal lines  =  group median, box edges  = 25th and 75th percentiles, and outliers (+) defined as values larger than q3+1.5*(q3−q1) or smaller than q1−1.5*(q3−q1). Significant difference between groups, determined using a two-tailed paired <i>t</i> test, is indicated by * (p<0.05).</p

Illustration of the adapted tissue residue function r(t) used in the two-stage model.

<p>The ASL signal arises from two sources: the non-exchanging, ‘pre-capillary blood volume’ (volume fraction f_pc), and the exchanging, capillary blood volume (volume fraction 1- f_pc). Labelled blood traverses the pre-capillary stage during the ‘pre-capillary transit time’ (pcTT), and arrives at the capillary bed at the ‘capillary bolus arrival time’ (BAT_c).</p

Results from the analysis of simulated ASL datasets, containing both a pre-capillary component (initial peak in dM curve around TI = 0.6 s) and an exchanging capillary component (second peak in dM curve, around TI = 1.6 s).

<p>(A) Simulated raw ASL data, for f_pc values ranging between 0 and 1 (see color bar), with the total signal sampled at 12 TI times (filled circles). The fits to the raw data from the two-stage and single-stage models are shown in (B) and (C) respectively. (D) Bayesian information criteria (BIC) value from fitting the single-stage (red) and two-stage (blue) models, as a function of f_pc. The model producing the lower BIC value is the preferred model.</p

Comparison of time of flight angiography data and two-stage ASL model fitting in a healthy adult.

<p>(A) Axial maximum intensity projection from time of flight angiography, showing large arteries such as the anterior, middle, and posterior cerebral arteries. (B) Maps of the fitted f_pc parameter (pre-capillary blood volume), derived from ASL data collected in the same subject.</p

Examples of standard T2w and T1w (post contrast) images obtained in three brain tumor patients, with fitted values of cerebral blood flow (CBF), pre-capillary blood volume (f_pc) and bolus arrival time at the capillary bed (BAT_c) overlaid.

<p>The top row shows data from a 10 year old male with a glioblastoma multiforme (WHO grade IV). The middle row shows data from a 15 year old male with a ganglioglioma (WHO grade I), and the bottom row is from a 7 year old female with an anaplastic ganglioglioma (WHO grade III). The white arrows highlight regions of increased f_pc and BAT_c in the tumor region. Fitted parameter maps are shown after affine registration to the FLASH images acquired during the same imaging session.</p