Improving Maize Production and Ground-Water Quality through Nitrogen Management in Minnesota’s Irrigated Coarse-Textured Soils

University of Minnesota M.S. thesis. March 2016. Major: Land and Atmospheric Science. Advisor: Fabián Fernández. 1 computer file (PDF); vi, 69 pages.Elevated groundwater nitrate (NO3-N) concentrations in irrigated sandy soils under corn (Zea mays L.) production in the Midwest is of increasing concern, and has prompted the need to identify new or enhanced nitrogen (N) management practices in these areas. The objective of this study was to evaluate agricultural technologies that may improve N management for profitable corn production and mitigate negative effects of NO3-N in groundwater. From 2011 to 2014 corn was grown at two sites in Minnesota on sandy soils, Dakota County, MN with a continuous corn (CC) rotation and Pope County, MN with a CC, corn after soybeans (CSB), and soybean after corn (SbC) rotations. Twelve treatments were applied including urea broadcast at rates of 0, 45, 90, 135, 180, 225, 270, and 315 kg N ha-1 as a split application, half at pre-plant and half at the V4 development stage, pre-plant Super U at 180 kg N ha-1, and pre-plant ESN at 180 and 225 kg N ha-1. Canopy sensing with SPAD, GreenSeeker, and Crop Circle was done at V8 and V12 and NO3-N basal stalk measurements at R6 development stage. Soil water NO3-N samples were collected weekly throughout the growing season below the rooting zone using suction lysimeters. The mean Maximum Return to N (MRTN) was 231 kg ha-1 and produced a mean-yield increase above the unfertilized check of 6.5 Mg ha-1. Canopy sensors and plant measurements provided limited utility and generally under-predicted N needs. Nitrogen use efficiency and yields were increased with split-applied urea compared to all other pre-plant sources at 180 kg N ha-1, but no reduction in NO3-N leaching occurred. Season-long NO3-N concentrations ranged from 10 to 46 mg L-1 and overall annual loss was 27 to 41 kg NO3-N ha-1. Reducing N rate below the MRTN substantially reduced yield without reducing NO3-N leaching losses.Struffert, Anne. (2016). Improving Maize Production and Ground-Water Quality through Nitrogen Management in Minnesota’s Irrigated Coarse-Textured Soils. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/180198

Changes of Radial Diffusivity and Fractional Anisotopy in the Optic Nerve and Optic Radiation of Glaucoma Patients

Purpose of this study was to evaluate with diffusion-tensor imaging (DTI) changes of radial diffusivity (RD) and fractional anisotropy (FA) in the optic nerve (ON) and optic radiation (OR) in glaucoma and to determine whether changes in RD and FA correlate with disease severity. Therefore, glaucoma patients and controls were examined using 3T. Regions of interest were positioned on RD and FA maps, and mean values were calculated for ON and OR and correlated with optic nerve atrophy and reduced spatial-temporal contrast sensitivity (STCS) of the retina. We found, that RD in glaucoma patients was significantly higher in the ON (0.74 ± 0.21 versus 0.58 ± 0.17·10−3 mm2 s−1; P < 0.05) and OR (0.79 ± 0.23 versus 0.62 ± 0.14·10−3 mm2 s−1; P < 0.05) compared to controls. Aside, FA was significantly decreased (0.48 ± 0.15 versus 0.66 ± 0.12 and 0.50 ± 0.20 versus 0.66 ± 0.11; P < 0.05). Hereby, correlation between changes in RD/FA and optic nerve atrophy/STCS was observed (r > 0.77). In conclusion, DTI at 3 Tesla allows robust RD and FA measurements in the ON and OR. Hereby, the extent of RD increase and FA decrease in glaucoma correlate with established ophthalmological examinations

Disinfection of Shared Mobile Phones Carried by Registered Nurses: A Comparison of Two Methods

This study determined the efficacy of cleaning products on mobile phones. Previous research has demonstrated the risk for bacterial cross contamination between healthcare workers\u27 hands, close contact equipment, and mobile communication devices. There is extensive literature on survival of organisms on inanimate objects. Mobile communication devices can act as a reservoir for bacteria associated with nosocomial infection. Additional studies show cross contamination between the healthcare workers hands, the mobile phones, and the patient.https://digitalcommons.centracare.com/nursing_posters/1025/thumbnail.jp

Bacteria on Shared Mobile Phones Can Lead to Infections

It\u27s now a common practice for hospital-owned mobile phones to be shared among healthcare employees from shift to shift. Despite the benefit of increased, timely communication between caregivers, sharing mobile devices can lead to the spread of healthcare-associated infections (HAIs) if they aren\u27t properly disinfected. The Guidelines for Disinfection and Sterilization in Healthcare Facilities describe non-critical environmental surfaces as items that are frequently touched by the hand and may pose a risk of secondary infection transmission

You Missed a Spot! Disinfecting Shared Mobile Phones

The use of portable mobile devices has facilitated timely communication among healthcare team members. It\u27s now a common practice for hospital-owned mobile phones to be shared among healthcare employees from shift to shift. Despite the benefit of increased, timely communication between caregivers, sharing mobile devices can lead to the spread of healthcare-associated infections (HAIs). This article looks at the efficacy of two types of cleaning products on shared mobile phones carried by RNs at a 489-bed, Magnet-designated, Midwestern regional medical center. The cleaning methods evaluated were 70% isopropyl alcohol wipes and ethyl alcohol wipes

Optimized Flat-Detector CT in Stroke Imaging: Ready for First-Line Use?

Background: Using flat-detector CT (FD-CT) for stroke imaging has the advantage that both diagnostic imaging and endovascular therapy can be performed directly within the Angio Suite without any patient transfer and time delay. Thus, stroke management could be speeded up significantly, and patient outcome might be improved. But as precondition for using FD-CT as primary imaging modality, a reliable exclusion of intracranial hemorrhage (ICH) has to be possible. This study aimed to investigate whether optimized native FD-CT, using a newly implemented reconstruction algorithm, may reliably detect ICH in stroke patients. Additionally, the potential to identify ischemic changes was evaluated. Methods: Cranial FD-CT scans were obtained in 102 patients presenting with acute ischemic stroke (n = 32), ICH (n = 45) or transient ischemic attack (n = 25). All scans were reconstructed with a newly implemented half-scan cone-beam algorithm. Two experienced neuroradiologists, unaware of clinical findings, evaluated independently the FD-CTs screening for hemorrhage or ischemic signs. The findings were correlated to CT, and rater and inter-rater agreement was assessed. Results: FD-CT demonstrated high sensitivity (95-100%) and specificity (100%) in detecting intracerebral and intraventricular hemorrhage (IVH). Overall, interobserver agreement (κ = 0.92) was almost perfect and rater agreement to CT highly significant (r = 0.81). One infratentorial ICH and 10 or 11 of 22 subarachnoid hemorrhages (SAHs) were missed of whom 7 were perimesencephalic. The sensitivity for detecting acute ischemic signs was poor in blinded readings (0 or 25%, respectively). Conclusions: Optimized FD-CT, using a newly implemented reconstruction algorithm, turned out as a reliable tool for detecting supratentorial ICH and IVH. However, detection of infratentorial ICH and perimesencephalic SAH is limited. The potential of FD-CT in detecting ischemic changes is poor in blinded readings. Thus, plain FD-CT seems insufficient as a standalone modality in acute stroke, but within a multimodal imaging approach primarily using the FD technology, native FD-CT seems capable to exclude reliably supratentorial hemorrhage. Currently, FD-CT imaging seems not yet ready for wide adoption, replacing regular CT, and should be reserved for selected patients. Furthermore, prospective evaluations are necessary to validate this approach in the clinical setting

Visualization of large vessel occlusion, clot extent, and collateral supply using volume perfusion flat detector computed tomography in acute stroke patients

Background Flat detector computed tomography angiography (FDCTA) can be reconstructed from volume perfusion flat detector computed tomography (VP-FDCT). Thus, CTA equivalent stroke imaging might be feasible within the angio suite. Purpose To evaluate the diagnostic accuracy of FDCTA in detecting large vessel occlusion (LVO) and collateral supply in acute stroke patients. Material and Methods Sixteen patients with LVO of the anterior circulation were analyzed retrospectively. Each patient underwent a multimodal CT stroke protocol, subsequent VP-FDCT, and digital subtraction angiography (DSA) for endovascular stroke therapy. Angiographic images reconstructed secondarily from VP-FDCT were evaluated with regard to visualization of LVO, Collateral Score (CS), Clot Burden Score (CBS), and image quality. Results Image quality of FDCTA was sufficient for diagnosis with a strong correlation between CTA and FDCTA (median score: CTA = 4 ± 0.447; FDCTA = 4 ± 0.5). Detection of LVO could be achieved with high sensitivity and specificity for FDCTA and CTA (97.9%, 95% confidence interval [CI] = 96.0–99.9; 92.6%, 95% CI = 84.3–100.0 vs. 96.8%, 95% CI = 93.2–100.0; 86.3%, 95% CI = 88.2–95.2). CBS and CS assessment showed no significant difference between FDCTA and CTA for both readers (reader1CBS: P = 0.751, reader1CS: P = 0.718; reader2CBS: P = 0.164; reader2CS: P = 0.582) and an excellent interrater agreement (CTACBSICC = 0.984, FDCTACBSICC = 0.951; CTACSICC = 0.754, FDCTACSICC = 0.789). Conclusion FDCTA, reconstructed from VP-FDCT data, allows reliable detection of ICA or MCA M1 segment occlusion comparable to CTA and may provide information concerning the clot extent with sufficient image quality

Flat-detector computed tomography evaluation in an experimental animal aneurysm model after endovascular treatment: A pilot study

We compared flat-detector computed tomography angiography (FD-CTA) to multislice computed tomography (MS-CTA) and digital subtracted angiography (DSA) for the visualization of experimental aneurysms treated with stents, coils or a combination of both. In 20 rabbits, aneurysms were created using the rabbit elastase aneurysm model. Seven aneurysms were treated with coils, seven with coils and stents, and six with self-expandable stents alone. Imaging was performed by DSA, MS-CTA and FD-CTA immediately after treatment. Multiplanar reconstruction (MPR) was performed and two experienced reviewers compared aneurysm/coil package size, aneurysm occlusion, stent diameters and artifacts for each modality. In aneurysms treated with stents alone, the visualization of the aneurysms was identical in all three imaging modalities. Residual aneurysm perfusion was present in two cases and visible in DSA and FD-CTA but not in MS-CTA. The diameter of coil-packages was overestimated in MS-CT by 56% and only by 16% in FD-CTA compared to DSA (p < 0.05). The diameter of stents was identical for DSA and FD-CTA and was significantly overestimated in MS-CTA (p < 0.05). Beam/metal hardening artifacts impaired image quality more severely in MS-CTA compared to FD-CTA. MS-CTA is impaired by blooming and beam/metal hardening artifacts in the visualization of implanted devices. There was no significant difference between measurements made with noninvasive FD-CTA compared to gold standard of DSA after stenting and after coiling/stent-assisted coiling of aneurysms. FD-CTA may be considered as a non-invasive alternative to the gold standard 2D DSA in selected patients that require follow up imaging after stenting

Open Spinal Dysraphism Without Hindbrain Herniation—Natural History and Postnatal Outcome

Objective: To report the natural history of fetuses with open spinal dysraphism (OSD) without hindbrain herniation (HBH) during second-trimester evaluation. Methods: A multicenter retrospective cohort study was conducted across three prenatal centers to evaluate fetuses with OSD. We reviewed cases with postnatally confirmed OSD without prenatal HBH at 19–27 weeks. Standardized prenatal evaluation consisted of repetitive ultrasound and magnetic resonance imaging. Postnatal outcome measures involved imaging, intraoperative findings and neurological function tests. Results: Among 280 fetuses with OSD, evaluated at a median gestational age of 21 weeks, a total of 12 (4%) lacked HBH. Moderate ventriculomegaly was observed in 33% of cases without HBH. Corpus callosum anomalies were not detected. Postnatally, HBH was present in 50%, while the shunt rate remained low (20%). In 80%, postnatal motor function (MF) was equal to or better based on the anatomical level. In 33%, MF after birth declined in comparison to the first fetal functional assessment in the second trimester. Conclusion: Fetuses with OSD and absent HBH in the second trimester demonstrate a low postnatal shunt rate. MF was frequently impaired at the initial second-trimester assessment, and in about a third of cases, postnatal MF seemed to have worsened. These findings may inform counseling and question the place of fetal surgery for this subgroup.</p

Evaluation After Cochlear Implant Surgery

Purpose Assessment of the cochlear implant (CI) electrode array position using flat-detector computed tomography (FDCT) to test dependence of postoperative outcome on intracochlear electrode position. Methods A total of 102 patients implanted with 107 CIs underwent FDCT. Electrode position was rated as 1) scala tympani, 2) scala vestibuli, 3) scalar dislocation and 4) no deconvolution. Two independent neuroradiologists rated all image data sets twice and the scalar position was verified by a third neuroradiologist. Presurgical and postsurgical speech audiometry by the Freiburg monosyllabic test was used to evaluate auditory outcome after 6 months of speech rehabilitation. Results Electrode array position was assessed by FDCT in 107 CIs. Of the electrodes 60 were detected in the scala tympani, 21 in the scala vestibuli, 24 electrode arrays showed scalar dislocation and 2 electrodes were not placed in an intracochlear position. There was no significant difference in rehabilitation outcomes between scala tympani and scala vestibuli inserted patients. Rehabilitation was also possible in patients with dislocated electrodes. Conclusion The use of FDCT is a reliable diagnostic method to determine the position of the electrode array. In our study cohort, the electrode position had no significant impact on postoperative outcome except for non-deconvoluted electrode arrays