The role of social networks in students’ learning experiences

The aim of this research is to investigate the role of social networks in computer science education. The Internet shows great potential for enhancing collaboration between people and the role of social software has become increasingly relevant in recent years. This research focuses on analyzing the role that social networks play in students’ learning experiences. The construction of students’ social networks, the evolution of these networks, and their effects on the students’ learning experience in a university environment are examined

Concave Pit-Containing Scaffold Surfaces Improve Stem Cell-Derived Osteoblast Performance and Lead to Significant Bone Tissue Formation

Scaffold surface features are thought to be important regulators of stem cell performance and endurance in tissue engineering applications, but details about these fundamental aspects of stem cell biology remain largely unclear.In the present study, smooth clinical-grade lactide-coglyolic acid 85:15 (PLGA) scaffolds were carved as membranes and treated with NMP (N-metil-pyrrolidone) to create controlled subtractive pits or microcavities. Scanning electron and confocal microscopy revealed that the NMP-treated membranes contained: (i) large microcavities of 80-120 microm in diameter and 40-100 microm in depth, which we termed primary; and (ii) smaller microcavities of 10-20 microm in diameter and 3-10 microm in depth located within the primary cavities, which we termed secondary. We asked whether a microcavity-rich scaffold had distinct bone-forming capabilities compared to a smooth one. To do so, mesenchymal stem cells derived from human dental pulp were seeded onto the two types of scaffold and monitored over time for cytoarchitectural characteristics, differentiation status and production of important factors, including bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF). We found that the microcavity-rich scaffold enhanced cell adhesion: the cells created intimate contact with secondary microcavities and were polarized. These cytological responses were not seen with the smooth-surface scaffold. Moreover, cells on the microcavity-rich scaffold released larger amounts of BMP-2 and VEGF into the culture medium and expressed higher alkaline phosphatase activity. When this type of scaffold was transplanted into rats, superior bone formation was elicited compared to cells seeded on the smooth scaffold.In conclusion, surface microcavities appear to support a more vigorous osteogenic response of stem cells and should be used in the design of therapeutic substrates to improve bone repair and bioengineering applications in the future

Thirty-day Outcome of Delayed Versus Early Management of Symptomatic Carotid Stenosis

Background: The aim of this study was to compare outcomes of early (<15 days) versus delayed carotid endarterectomy (CEA) in symptomatic patients. Methods: All CEA procedures performed for symptomatic carotid stenosis between January 2006 and May 2010 were retrospectively reviewed. Postoperative mortality (within 30 days), stroke, and myocardial infarction (MI) rates were analyzed in the early and delayed CEA groups. Results: During the study period, 149 patients were included. Carotid revascularization was performed within 15 days after symptom onset in 62 (41.6%) patients and longer than 15 days after symptom onset in 87 (58.4%) patients. The mean time lapse between onset of neurological symptoms and surgery was 9.3 days (range 1-15) in the early surgery group and 47.9 days (range 16-157) in the delayed surgery group. Thirty-day combined stroke and death rates were, respectively, 1.7% and 3.5% in the early and the delayed surgery groups. Thirty-day combined stroke, death, and MI rates were, respectively, 1.7% and 5.9% in the early and the delayed surgery groups. Conclusion: During the study period, the reduction of the symptom-to-knife time in application to the carotid revascularization guidelines did not impact our outcomes suggesting that early CEA achieves 30-day mortality and morbidity rates at least equivalent to those of delayed CEA

Laparoscopic Resection of a Middle Colic Artery Aneurysm.

We report herein the successful laparoscopic resection of an asymptomatic 3-cm middle colic artery aneurysm in a young woman. Endovascular treatment represents nowadays the first-line option facing visceral artery aneurysm, but in this case, embolization was excluded because of hostile anatomy. Advantages of laparoscopic approach were the safe resection of the aneurysm with immediate evaluation of the bowel tolerance and the possibility of a histological examination of the arterial wall, without the disadvantages of laparotomy

Use of the Flixene vascular access graft as an early cannulation solution.

OBJECTIVE: The primary end points of this study were safety and efficacy of early cannulation of the Flixene graft (Maquet-Atrium Medical, Hudson, NH). Secondary end points were complications and patency. METHODS: This is a prospective single-center nonrandomized study. Study data included patient characteristics; history of vascular access; operative technique; interval between implantation and initial cannulation; complications; and patency at 1 month, 3 months, and every 6 months. Patency rates were estimated by the Kaplan-Meier method. RESULTS: Between January 2011 and September 2013, a total of 46 Flixene grafts were implanted in 44 patients (27 men) with a mean age of 63 years. The implantation site was the upper arm in 67% of cases, the forearm in 11%, and the thigh in 22%. Seven grafts were never cannulated during the study period. Of the remaining 39 grafts, 32 (82%) were successfully cannulated within the first week after implantation, including 16 (41%) on the first day. The median interval from implantation to initial cannulation was 2 days (interquartile range, 1-3 days). The median follow-up was 223.5 days (interquartile range, 97-600 days). Five hematomas occurred, but only one required surgical revision. Primary assisted and secondary patency rates were 65% and 86%, respectively, at 6 months and 56% and 86%, respectively, at 1 year. CONCLUSIONS: This study suggests that cannulation of the Flixene graft within 1 week after implantation is safe and effective. Early cannulation avoids or shortens the need for a temporary catheter. One-year patency rates appeared to be comparable to those achieved with conventional grafts, but long-term follow-up and randomized controlled studies will be needed to confirm this finding

Hemodynamic Conditions may Influence the Oversizing of Stent Grafts and the Postoperative Surveillance of Patients with Ruptured Abdominal Aortic Aneurysm Treated by EVAR.

To report the causes of second rupture in patients treated with a stent graft for ruptured abdominal aortic aneurysm (rAAA). A 69-year-old man was admitted for abdominal pain and hypovolemic shock 22 months after endovascular exclusion of an rAAA with an aortomonoiliac stent graft and a crossover bypass despite normal duplex ultrasound and sac shrinkage at 1 year. During emergent laparotomy, a type IA endoleak was discovered and the aortomonoiliac stent graft was explanted. A Dacron bypass was interposed between the infrarenal aorta and the iliac extension stent graft. Considering the literature, this report has 3 implications for the endovascular treatment of rAAA. First, 30% oversizing is preferable to 15% when treating an rAAA assessed by computed tomography angiography (CTA) performed during permissive hypotension. Second, the surveillance program should rely on CTA and not on a duplex examination to detect any endoleaks or migration. Finally, partial stent graft explantation is a valid option for decreasing aortic clamping time

Early cannulation of the Flixene? arteriovenous graft.

PURPOSE: The aim of this review was to search for evidence of the efficiency of early cannulation of the Flixene? (Maquet-Atrium Medical, Hudson, NH, USA) arteriovenous graft (AVG) in the current literature and to assess its patency and complication rates. METHODS: Searches in Pubmed, Medline, Embase and the Cochrane Library were performed using the following specific search terms: early cannulation AVG and/or Flixene? graft. The primary outcomes were mean time to first cannulation and patency rates at 12 months. Secondary outcomes were complications. RESULTS: Six studies reporting outcomes in a total of 260 procedures were included in this review. The median delay from intervention to first cannulation was documented in four studies and was less than 3 days. Primary assisted patency at 12 months ranged from 45% to 53% in the four documented series. In five studies, documented secondary patency at 12 months ranged from 63% to 92%. Two studies compared outcomes between traditional and Flixene? grafts: one study reported significantly (p&lt;0.01) improved one-year patency using the Flixene? graft, the two studies did not report significant differences in complication rates between both groups. The rate of infection and pseudo-aneurysm formation ranged from 0 to 11% and 0 to 6%, respectively. CONCLUSIONS: This review shows that early cannulation of the Flixene? graft within 3 days following its implantation is feasible with one-year patency and complication rates equivalent to those of conventional grafts which can be cannulated only after 2 weeks