Dynamic Imaging of Distant Object with Ptychographical Intensity Interferometry

Author(s):  
Yuchen He ◽  
Yuan Yuan ◽  
Hui Chen ◽  
Huaibin Zheng ◽  
JIanbin Liu ◽  
...  
2016 ◽  
Vol 33 (1) ◽  
pp. 92-116 ◽  
Author(s):  
David K. Blake

By examining folk music activities connecting students and local musicians during the early 1960s at the University of Illinois at Urbana-Champaign, this article demonstrates how university geographies and musical landscapes influence musical activities in college towns. The geography of the University of Illinois, a rural Midwestern location with a mostly urban, middle-class student population, created an unusual combination of privileged students in a primarily working-class area. This combination of geography and landscape framed interactions between students and local musicians in Urbana-Champaign, stimulating and complicating the traversal of sociocultural differences through traditional music. Members of the University of Illinois Campus Folksong Club considered traditional music as a high cultural form distinct from mass-culture artists, aligning their interests with then-dominant scholarly approaches in folklore and film studies departments. Yet students also interrogated the impropriety of folksong presentation on campus, and community folksingers projected their own discomfort with students’ liberal politics. In hosting concerts by rural musicians such as Frank Proffitt and producing a record of local Urbana-Champaign folksingers called Green Fields of Illinois (1963), the folksong club attempted to suture these differences by highlighting the aesthetic, domestic, historical, and educational aspects of local folk music, while avoiding contemporary socioeconomic, commercial, and political concerns. This depoliticized conception of folk music bridged students and local folksingers, but also represented local music via a nineteenth-century rural landscape that converted contemporaneous lived practice into a temporally distant object of aesthetic study. Students’ study of folk music thus reinforced the power structures of university culture—but engaging local folksinging as an educational subject remained for them the most ethical solution for questioning, and potentially traversing, larger problems of inequality and difference.


2016 ◽  
Vol 25 (2) ◽  
pp. 205-211 ◽  
Author(s):  
Antonio Giorgio ◽  
Luca Montesarchio ◽  
Piero Gatti ◽  
Ferdinando Amendola ◽  
Paolo Matteucci ◽  
...  

  Background & Aims: Disappearance of portal blood flow and arterial vascularization is the hallmark of hepatocarcinogenesis. The capability of a dynamic imaging modality detecting arterial hypervascularization of small nodules is crucial to promote a rapid diagnostic and therapeutic work-up improving survival. We aimed to evaluate the capability of CEUS to detect arterial vascularization of ≤ 2 cm HCC nodules arising during surveillance so as to shorten the diagnostic and therapeutic work-up. Methods: From October 2009 to September 2014, among 1757 consecutive cirrhotic patients under surveillance with ultrasound (US), 243 patients had new single nodules 7-20 mm; 229/243 had a conclusive histologic diagnosis and comprised the study group. All patients underwent CEUS followed by enhanced MRI and US guided percutaneous 18G needle core biopsy of the nodules. Of the 229 nodules, 27 were hyperechoic, 171 hypoechoic and 31 isoechoic lesions. Results: The histology results revealed that 199/229 nodules were HCC and 30 were benign. Of 199 HCC, CEUS evidenced arterial hypervascularity in 190 nodules (95.5%) (sensitivity 94.48 %, specificity 100%, PPV 100%, NPV 76.92 %). Of the 39 CEUS arterial-unenhanced nodules, 30 were benign and 9 (23%) were well-differentiated HCC. eMRI showed arterial hypervascularity in 199 nodules (86,9%). Of these, only 193 (97%) were histologically HCCs while 6 were benign (sensitivity: 97%, specificity: 80%, PPV: 97%, NPV: 80%). Conclusions: CEUS has a great capability to detect arterial hypervascularity of small HCC. Because only 4.5% of new nodules escape the demonstration of arterial hyervascularity, CEUS must be performed immediately after conventional US to contrast the malignant fate of small lesions arising in a cirrhotic liver.. Abbreviations: CEUS: contrast-enhanced ultrasound; CT: computed tomography; HCC: hepatocellular carcinoma;MRI: magnetic resonance; NPV: negative predictive value; PPV: positive predictive value; US: ultrasonography.


2020 ◽  
Vol 132 (4) ◽  
pp. 1234-1242 ◽  
Author(s):  
Paolo Belardinelli ◽  
Ramin Azodi-Avval ◽  
Erick Ortiz ◽  
Georgios Naros ◽  
Florian Grimm ◽  
...  

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for symptomatic Parkinson’s disease (PD); the clinical benefit may not only mirror modulation of local STN activity but also reflect consecutive network effects on cortical oscillatory activity. Moreover, STN-DBS selectively suppresses spatially and spectrally distinct patterns of synchronous oscillatory activity within cortical-subcortical loops. These STN-cortical circuits have been described in PD patients using magnetoencephalography after surgery. This network information, however, is currently not available during surgery to inform the implantation strategy.The authors recorded spontaneous brain activity in 3 awake patients with PD (mean age 67 ± 14 years; mean disease duration 13 ± 7 years) during implantation of DBS electrodes into the STN after overnight withdrawal of dopaminergic medication. Intraoperative propofol was discontinued at least 30 minutes prior to the electrophysiological recordings. The authors used a novel approach for performing simultaneous recordings of STN local field potentials (LFPs) and multichannel electroencephalography (EEG) at rest. Coherent oscillations between LFP and EEG sensors were computed, and subsequent dynamic imaging of coherent sources was performed.The authors identified coherent activity in the upper beta range (21–35 Hz) between the STN and the ipsilateral mesial (pre)motor area. Coherence in the theta range (4–6 Hz) was detected in the ipsilateral prefrontal area.These findings demonstrate the feasibility of detecting frequency-specific and spatially distinct synchronization between the STN and cortex during DBS surgery. Mapping the STN with this technique may disentangle different functional loops relevant for refined targeting during DBS implantation.


2020 ◽  
Vol 33 (6) ◽  
pp. 727-733
Author(s):  
Jasmine A. T. DiCesare ◽  
Alexander M. Tucker ◽  
Irene Say ◽  
Kunal Patel ◽  
Todd H. Lanman ◽  
...  

Cervical spondylosis is one of the most commonly treated conditions in neurosurgery. Increasingly, cervical disc replacement (CDR) has become an alternative to traditional arthrodesis, particularly when treating younger patients. Thus, surgeons continue to gain a greater understanding of short- and long-term complications of arthroplasty. Here, the authors present a series of 4 patients initially treated with Mobi-C artificial disc implants who developed postoperative neck pain. Dynamic imaging revealed segmental kyphosis at the level of the implant. All implants were locked in the flexion position, and all patients required reoperation. This is the first reported case series of symptomatic segmental kyphosis after CDR.


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