Through a glass darkly: a case for the study of virtual space

This paper begins to examine the similarities and differences between virtual space and real space, as taken from anarchitectural (as opposed to a biological, psychological, geographic, philosophical or information theoretic)standpoint. It continues by introducing a number of criteria, suggested by the authors as being necessary for virtualspace to be used in a manner consistent with our experience of real space. Finally, it concludes by suggesting apedagogical framework for the benefits and associated learning outcomes of the study and examination of thisrelationship. This is accompanied by examples of recent student work, which set out to investigate this relationship

Successful Management of a Rare Case of Stent Fracture and Subsequent Migration of the Fractured Stent Segment Into the Ascending Aorta in In-Stent Restenotic Lesions of a Saphenous Vein Graft

Stent fracture is a complication following implantation of drug eluting stents and is recognized as one of the risk factors for in-stent restenosis. We present the first case of successfully managing a stent fracture and subsequent migration of the fractured stent into the ascending aorta that occurred during repeat revascularization for in-stent restenosis of an ostium of saphenous vein graft after implantation of a zotarolimus-eluting stent. Although the fractured stent segment had migrated into the ascending aorta with a pulled balloon catheter, it was successfully repositioned in the saphenous vein graft using an inflated balloon catheter. Then, the fractured stent segment was successfully connected to the residual segment of the zotarolimus-eluting stent by covering it with an additional sirolimuseluting stent

Transient Right Ventricular Dysfunction After Pericardiectomy in Patients With Constrictive Pericarditis

Pericardiectomy is the standard treatment in patients with chronic constrictive pericarditis who have persistent symptoms. However, myocardial atrophy with prolonged pericardial constriction and abrupt increase in venous return can lead to heart failure with volume overload after pericardial decompression, especially in the right ventricle (RV). We experienced a 44 year old male patient who developed transient RV failure after pericardiectomy for constrictive pericarditis. Echocardiography revealed a markedly dilated RV with decreased peak systolic velocity of the tricuspid annulus, suggesting severe RV dysfunction. After treatment with inotropics and diuretics, a follow-up echocardiography revealed an improved systolic function with decreased RV chamber size. This case demonstrates the importance of volume overload and RV dysfunction in patients with constrictive pericarditis undergoing pericardiectomy

Comparisons of the Effects of Stent Eccentricity on the Neointimal Hyperplasia between Sirolimus-Eluting Stent versus Paclitaxel-Eluting Stent

PURPOSE: Previous studies suggested that asymmetric stent expansion did not affect suppression of neointimal hyperplasia (NIH) after sirolimus-eluting stents (SES) implantation. The aim of this study was to evaluate the effects of stent eccentricity (SE) on NIH between SES versus paclitaxel-eluting stents (PES) using an intravascular ultrasound (IVUS) analysis from the randomized trial. MATERIALS AND METHODS: Serial IVUS data were obtained from Post-stent Optimal Expansion (POET) trial, allocated randomly to SES or PES. Three different SE (minimum stent diameter divided by maximum stent diameter) were evaluated; SE at the lesion site with maximal %NIH area (SE-NIH), SE at the minimal stent CSA [SE-minimal stent area (SE-MSA)], and averaged SE through the entire stent (SE-mean). We classified each drug-eluting stents (DES) into the concentric (≥ mean SE) and eccentric groups (< mean SE) based on the mean value of SE. RESULTS: Among 301 enrolled patients, 233 patients [SES (n = 108), PES (n = 125)] underwent a follow-up IVUS. There was no significant correlation between %NIH area and SE-NIH (r = - 0.083, p = 0.391) or SE-MSA (r = - 0.109, p = 0.259) of SES. However, SE-NIH of PES showed a weak but significant correlation with %NIH area (r = 0.269, p < 0.01). As to the associations between SEmean and NIH volume index, SES revealed no significant correlation (r = - 0.001, p = 0.990), but PES showed a weak but significant correlation (r = 0.320, p < 0.01). However, there was no difference in the restenosis rate between the eccentric versus concentric groups of both DES. CONCLUSION: This study suggests that lower SE of both SES and PES, which means asymmetric stent expansion, may not be associated with increased NIH.ope

Photometric Selection of Unobscured QSOs in the Ecliptic Poles: KMTNet in the South Field and Pan-STARRS in the North Field

We search for quasi-stellar objects (QSOs) in a wide area of the south ecliptic pole (SEP) field, which has been and will continue to be intensively explored through various space missions. For this purpose, we obtain deep broadband optical images of the SEP field covering an area of $\sim$$14.5\times14.5$ deg$^2$ with the Korea Microlensing Telescope Network. The 5$\sigma$ detection limits for point sources in the $BVRI$ bands are estimated to be $\sim$22.59, 22.60, 22.98, and 21.85 mag, respectively. Utilizing data from Wide-field Infrared Survey Explorer, unobscured QSO candidates are selected among the optically point-like sources using the mid-infrared (MIR) and optical-MIR colors. To further refine our selection and eliminate any contamination not adequately removed by the color-based selection, we perform the spectral energy distribution fitting with archival photometric data ranging from optical to MIR. As a result, we identify a total of 2,383 unobscured QSO candidates in the SEP field. We also apply a similar method to the north ecliptic pole field using the Pan-STARRS data and obtain a similar result of identifying 2,427 candidates. The differential number count per area of our QSO candidates is in good agreement with those measured from spectroscopically confirmed ones in other fields. Finally, we compare the results with the literature and discuss how this work will be implicated in future studies, especially with the upcoming space missions.Comment: 14 pages, 9 figures, accepted for publication in ApJ

Impact of the Metabolic Syndrome on the Clinical Outcome of Patients with Acute ST-Elevation Myocardial Infarction

We sought to determine the prevalence of metabolic syndrome (MS) in patients with acute myocardial infarction and its effect on clinical outcomes. Employing data from the Korea Acute Myocardial Infarction Registry, a total of 1,990 patients suffered from acute ST-elevation myocardial infarction (STEMI) between November 2005 and December 2006 were categorized according to the National Cholesterol Education Program-Adult Treatment Panel III criteria of MS. Primary study outcomes included major adverse cardiac events (MACE) during one-year follow-up. Patients were grouped based on existence of MS: group I: MS (n=1,182, 777 men, 62.8±12.3 yr); group II: Non-MS (n=808, 675 men, 64.2±13.1 yr). Group I showed lower left ventricular ejection fraction (LVEF) (P=0.005). There were no differences between two groups in the coronary angiographic findings except for multivessel involvement (P=0.01). The incidence of in-hospital death was higher in group I than in group II (P=0.047), but the rates of composite MACE during one-year clinical follow-up showed no significant differences. Multivariate analysis showed that low LVEF, old age, MS, low high density lipoprotein cholesterol and multivessel involvement were associated with high in-hospital death rate. In conclusion, MS is an important predictor for in-hospital death in patients with STEMI