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Illumination has been long known to affect semiconductor defect properties during either growth or operating processes. Current theories of studying the illumination effects on defects usually have the assumption of unaffected formation energies of neutral defects as well as defect transition energy levels, and use the quasi-Fermi levels to describe behaviors of excess carriers with conclusions at variance. In this work, we first propose a method to simulate steady illumination conditions, based on which we demonstrate that formation energies of neutral defects and defect transition energy levels are insensitive to illumination. Then, we show that optical and thermal excitation of electrons can be seen equivalent with each other to reach a steady electron distribution in a homogeneous semiconductor. Consequently, the electron distribution can be characterized using just one effective temperature T^{′} and one universal Fermi level E_{F}^{^{′}} for a homogeneous semiconductor under continuous and steady illuminations, which can be seen as a combination of quasiequilibrium electron system with T^{′} and a lattice system with T. Using these concepts, we uncover the universal mechanisms of illumination effects on charged defects by treating the band-edge states explicitly on the same footing as the defect states. We find that the formation energies of band-edge “defect” states shift with increased T^{′} of electrons, thus affecting the E_{F}^{^{′}}, changing defect ionic probabilities, and affecting concentrations of charged defects. We apply our theory to study the illumination effects on the doping behaviors in GaN:Mg and CdTe:Sb, obtaining results in accordance with experimental observations. More interesting experimental defect-related phenomena under steady illuminations are expected to be understood from our theory.

Defects play significant roles in spin-current-related physical processes in intrinsic ferromagnetic semiconductors (FMSs), which are great promise for spintronics applications. However, current defect calculation methods cannot be used to investigate charged defects in FMSs due to the spin polarization of both the charged defect states and ionized carriers, which is not well treated in current defect calculation methods. In order to solve this problem, we propose a spin-distinguishable charge correction (SDCC) method that uses spin-polarized band edge charge density instead of spin-unpolarized uniform background charge density as the compensating charge for charged defects. We apply our method to study the defect properties of CrI _3 monolayer and find it can be doped n-type under the Cr-rich growth condition but difficult to be doped p-type. The SDCC method proposed here is generally suitable for all FMSs, which will be useful for the studies of defect properties of magnetic semiconductors.

The Low-profile Visualized Intraluminal Support (LVIS) device is a new generation of self-expanding braided stent recently introduced in China for stent assisted coiling of intracranial aneurysms. The aim of our study is to evaluate the feasibility, safety, and efficacy of the LVIS device in reconstructive treatment of vertebral artery dissecting aneurysms (VADAs).We retrospectively reviewed the neurointerventional database of our institution from June 2014 to May 2016. Patients who underwent endovascular treatment of VADAs with LVIS stents were included in this study. Clinical presentation, aneurysmal characteristics, technical feasibility, procedural complications, and angiographic and clinical follow-up results were evaluated.38 patients with VADAs who underwent treatment with LVIS stent were identified, including 3 ruptured VADAs. All VADAs were successfully treated with reconstructive techniques including the stent-assisted coiling (n = 34) and stenting only (n = 4). Post-procedural complications developed in 3 patients (7.9%) including two small brainstem infarctions and one delayed thromboembolic event. Complications resulted in one case of minor permanent morbidity (2.6%). There was no procedure-related mortality. The follow-up angiogram was available in 30 patients at an average of 8.3 months (range, 2 to 30 months), which revealed complete occlusion in 23 patients (76.7%), residual neck in five patients (16.7%), and residual sac in two patients (6.7%). The follow-up of 25 aneurysms with incomplete immediate occlusion revealed 22 aneurysms (88%) with improvement in the Raymond class. One aneurysm (3.3%) showed recanalization and required retreatment. Clinical followed-up at 5-28 months (mean 14.1 months) was achieved in 36 patients because two patients died of pancreatic cancer and basal ganglia hemorrhage, respectively. No new neurologic deterioration or aneurysm (re)bleeding was observed.Our preliminary experience with reconstruction of VADAs with the LVIS device demonstrates that this treatment approach is feasible with good short-term angiographic and clinical outcomes. Long-term and larger cohort studies are necessary to determine long-term outcomes of this therapy.

INTRODUCTIONFew studies focused on predictors of unfavorable outcomes (modified Rankin Scale, 2-6) after reconstructive treatment of the ruptured intracranial spontaneous vertebral artery dissection aneurysms (ris-VADAs), which was evaluated based on 57 reconstructed lesions in this study.METHODSResults of 57 consecutive patients (M:F = 29∶28; median age, 48 years; range, 27 to 69 years) harboring 57 ris-VADAs, which were treated with coils combined with single stent(n = 32), double overlapping stents (n = 16), and triple overlapping stents (n = 9) between October 2000 to March 2011, were retrospectively reviewed and analyzed.RESULTSThe available (n = 54) mean durations of angiographic and clinical follow-ups were 27 months (range, 12 to 78) and 62 months (range, 12 to 132), respectively. The involvement of PICA (p = 0.004), size of lesions (p = 0.000), quantity of stent (p = 0.001), and coil type (p = 0.002) affected the immediate obliteration grade, which was only risk factor for angiographic recurrences (p = 0.031). Although the post-treatment outcomes did not differ between single stent and multiple stents (p = 0.434), 5 angiographic recurrences, 1 rebleeding and 1 suspected rebleeding, all occurred in partial obliteration after single-stent-assisted coiling. Progressive thrombosis and in-stent obliteration were not detected on follow-up angiograms. Older age (odds ratio [OR] = 1.090; 95% confidence interval [CI], 1.004-1.184; p = 0.040) and unfavorable Hunt-Hess scale (OR = 4.289; 95%CI, 1.232-14.933; p = 0.022) were independent predictors of unfavorable outcomes in the reconstructed ris-VADAs.CONCLUSIONSImmediate obliteration grade was only risk factor for angiographic recurrence after reconstructive treatment. Unfavorable Hunt-Hess grade and older age were independent predictors of unfavorable outcomes in ris-VADAs.

Background and purpose Thoracolumbar and sacral spinal epidural arteriovenous fistulas (SEDAVFs) are an increasingly recognized form of spinal vascular malformation. The purpose of this study was to perform a systematic review of the demographics, clinical presentation and treatment results of thoracolumbar SEDAVF5. Materials and methods Pubmed, Scopus and Web of Science databases were searched from January 2000 to January 2018 for articles on treatment of SEDAVF5. Pooled data of individual patients were analyzed for demographic and clinical features of SEDAVF5 as well as treatment outcomes. Results There were 125 patients from 11 studies included. Mean age was 63.5 years. There was a male sex predilection (69.6%). Sensory symptoms including pain or numbness were the most frequently presenting symptoms. Fistula location was the lumbosacral spine in 79.2% and the thoracic spine in 20.8%. Involvement of intradural venous drainage was more common than extradural venous drainage only (89.6% vs 10.4%). Of the 123 treated patients, endovascular therapy was performed in 67.5% of patients, microsurgery in 23.6%, and combined treatment in 8.9%. The overall complete obliteration rate was 83.5% and did not differ between groups. Clinical symptoms improved in 70.7% of patients, were stable in 25%, and worsened in 1.7% with no difference between treatment modalities. Conclusions Thoracic and lumbosacral SEDAVF5 often present with symptoms secondary to congestive myelopathy or compressive symptoms. Both endovascular and microsurgical treatments were associated with high obliteration rates and good clinical outcomes. [ABSTRACT FROM AUTHOR]

Objective: Small anterior communicating artery aneurysms with recurrent bleeding and adjacent hematoma may have a high risk of post-operative rebleeding. This clinical study summarizes our preliminary experience with this subset of aneurysms, which were treated with endovascular coiling and subsequent Onyx 34 embolization. Methods: We retrospectively reviewed the data of 9 patients suffering from small anterior communicating artery aneurysms treated with the combination of coils and Onyx. The clinical characteristics, angiographic outcomes, and follow-up results are reviewed. Results: Endovascular coiling and Onyx embolization were successfully accomplished in all 9 cases. The Raymond scale ratings of the treatments are all class I with the parent arteries kept patent. One patient died of severe brain edema on the 5th post-operative day. The modified Rankin scale (mRS) score for the other 8 patients at follow-ups (6 m to 26 m, 15.8 m on average) was 0 in 5 cases, 1 in 2 cases, and 3 in 1 case. Seven of 8 patients (87.5%) underwent angiographic follow-up that demonstrated persistent durable occlusion with no recanalization. Conclusions: Endovascular coiling and subsequent Onyx 34 embolization may be effective in treating anterior communicating artery aneurysms with adjacent hematoma. Further studies with larger sample size and adequate follow-up are required to verify its safety and efficacy as well as to evaluate the longterm outcome. [ABSTRACT FROM AUTHOR]

Objective: Blood blister-like aneurysms (BBAs) are unique due to their high risk of recurrent bleeding associated with their fragile neck. The best treatment for BBAs is still controversial. This paper sought to evaluate the safety and efficacy of stent-assisted coiling and subsequent overlapping stents (SAC + OS) in the treatment of BBAs. Methods: Fifteen consecutive patients with ruptured BBAs managed with SAC + OS were enrolled in this study. The clinical characteristics, procedural data, angiographic outcome, and follow-up results were reviewed. Results: SAC + OS were successfully performed in all 15 cases. The instant angiographic result was total occlusion in 6 cases, residual neck in 7 cases, and residual aneurysm in 2 cases. Angiographic follow-ups revealed total occlusion in all 6 cases treated by triple or quadruple stents, and 6 of 9 cases treated by double stents. Major recanalization was detected in 3 cases treated by double stents. The modified Rankin Scale score at 4-52 months follow-up (23.8 months on average) was 0 in 6 cases, 1 in 8 cases, and 3 in one case. Conclusion: Stent-assisted coiling and subsequent overlapping stents are feasible and safe for BBAs. It can be helpful to further decrease the risk of recanalization with more stents. Early angiographic follow-up within 2 weeks is recommended. [ABSTRACT FROM AUTHOR]

Dural arteriovenous fistulas (DAVFs) are associated with venous hypertension. Numerous studies have revealed high expression levels of vascular endothelial growth factor (VEGF) in human DAVF specimens, as well as in animal models of experimental venous hypertension. Lhe objective of the present study was to clarify whether the VEGF signaling pathway is important in the development of DAVFs. Rats (n=216) were randomly divided into six groups. In the rats from five groups (groups A and C-E, n=45 in each group; group B, n=12), experimental venous hypertension was induced by right common carotid artery (CCA)-external jugular vein (EJV) anastomosis, superior sinus occlusion and left transver sinus occlusion, while the remaining group (group F, n=24) underwent sham surgery. The rats in group A received a VEGF recombinant adenovirus injection into the distal section of the right EJV 30 min prior to anastomosis of the CCA and EJV. An equivalent control adenovirus was injected into the right EJV of group B rats prior to anastomosis. The rats in group C received no virus prior to anastomosis and no medicine subsequent to surgery. The group D rats were lavaged with Vatalanib, a VEGF receptor (VEGFR) inhibitor, and the group E rats were lavaged with an equal quantity of saline weekly following surgery. Six rats from groups A-E and one rat from group F were sacrificed in the first, second, fourth and twelfth weeks after surgery for immunohistochemical analysis of VEGF expression and analysis of microvessel density. Cerebral angiography was performed on the remaining rats in each group on the twelfth [ABSTRACT FROM AUTHOR]

Background The treatment of large(10-25 mm) or giant(⩾25 mm) cerebral aneurysms remains technically challenging, with a much higher complication and recanalization rate than that is observed for smaller aneurysms. The use of a flow diverter seems to facilitate the treatment of this special entity. In a previous single-center prospective study approved by the Ethics Committee and China Food and Drug Administration (CFDA), we obtained promising results, showing remarkable safety and effectiveness for the Tubridge flow diverter. Nevertheless, the previous study may have been limited by biases due to its single-center design and limited number of subjects. Furthermore, although various articles have reported durable results from treating aneurysms using flow diverters, increasing questions have arisen about this form of treatment. Thus, prospective, multiple-center, randomized trials containing more subjects are needed. Methods/design This study is a multicenter, randomized, controlled clinical trial comparing clinical outcomes for patients with unruptured large/giant intracranial aneurysms treated with either conventional stent-assisted coiling or flow diverter implantation. A total of 124 patients who fulfill the inclusion and exclusion criteria will be randomized into either a treatment group or a control group in the ratio of 1:1. The treatment group will receive Tubridge implantation alone or combined with bared coils, and the control group will be treated with stent-assisted coiling (bare coils). The primary endpoint will be the complete occlusion rate at 6-month follow-up. Secondary endpoints include the immediate technique success rate, overall mortality, adverse events (ischemic stroke or intracranial bleeding) within 30 days, 90 days and 1 year post-operation, and the rate of intra-stent stenosis and thrombosis 6 months postoperation. Discussion This prospective trial may provide more information on the safety and efficacy of the Tubridge flow diverter and may potentially change the strategy for treatment of large or giant aneurysms. [ABSTRACT FROM AUTHOR]

Objectives: Blood blister-like aneurysms (BBAs) are aneurysms arising from the nonbranching arterial trunk, which are usually small and located at the anterior wall of supraclinoid internal carotid artery. These aneurysms are quite dangerous due to their fragile neck. This paper aims to evaluate the application of stent-assisted coil embolization in the treatment of BBAs. Methods: A retrospective review of the aneurysm database in our institution identified 8 patients carrying BBAs planned to be treated by stent-assisted coil embolization. The clinical characteristics, angiographic outcome, and follow-up results were reviewed. Results: Stent-assisted coil embolization was successfully performed in 5 cases (62.5%). Two procedures were treated with sole stent deployment (25%). One patient suffered intra-operative rupture (12.5%) and endovascular trapping was performed. The modified Rankin scale (mRs) score in living patients at discharge was 1 in four cases, 2 in one case, and 3 in one case. Two patients died of post-operative hemorrhage (25%). The mRs score at 9-36 months' follow-up was 0 in four cases, 1 in one case, and 2 in one case. All patients were followed up angiographically, and regrowth was observed in three patients, who accepted further endovascular treatments. Conclusion: Stent-assisted coil embolization may probably reduce the mortality, but may not be a cure for all BBAs. [ABSTRACT FROM AUTHOR]