bluuebunny/crossref_metadata_2025 huggingface dataset:
P-003 Endovascular Concurrent Use of Coils and Pipeline Embolization Device for Intracranial Aneurysms: Clinical and Angiographic Results
Authors: Nossek E , Chalif D , Lombardo K , Setton A
Published: July 2014

Background

The utility of the pipeline embolization device (PED) has been described as the sole device for treatment of brain aneurysms. The benefit using concurrent coils with limited number of PEDs is not well documented. We describe our experience with this technique as well as our mid-term clinical and angiographic results.

Methods

This is a retrospective review of patients treated for brain aneurysms between 2011–2014. In this cohort, 1–3 PEDs were deployed with the addition of coils using a “jailed” microcatheter technique. A partially dense coil mass was the goal, without complete neck occlusion. Technical difficulties were reviewed. Immediate clinical and angiographic results were obtained as well as mid-term and long-term clinical outcome and aneurysms occlusion rate. Once a patient demonstrated complete occlusion on contrast MRA, Plavix was discontinued.

Results

We have treated 26 patients using this technique. Median Age was 50.5 (range 31–78). The following aneurysms were treated: 1 Cavernous aneurysm; 17 proximal supraclinoid carotid, 3 posterior communicating artery aneurysms, 2 anterior choroidal artery aneurysms, 1 ICA bifurcation aneurysms and 2 intradural vertebral aneurysm. All underwent early post procedure clinical follow up.

There were no intra-procedural or post-procedural complications. All PEDs were successfully deployed. No early or delayed neurological nor neuro-ophthalmological deficits were encountered. No adverse effects due to the coil mass were observed. There were no clinical and radiographic signs of ischemia in this group. Steroids treatment was tapered quickly and discontinued within 5 days, without prolong severe headaches. During the imaging follow up, all patients demonstrated complete occlusion on the first MRA (3–5 month). Follow DSA angiography (6–9 month) confirmed complete occlusion without in-stent stenosis. All patients maintained their baseline clinical status.

Conclusions

We found that the deployment of limited PEDs with concurrent partially-dense coil embolization is safe and effective. This technique achieved early complete occlusion without inducing mass effect. Favorable clinical results were observed in all patients without prolong headaches.

Disclosures

E. Nossek: None. D. Chalif: None. K. Lombardo: None. A. Setton: None.
O-004 Final Results of the US Humanitarian Device Exemption Study of the Low-profile Visualised Intraluminal Support (LVIS) Device
Authors: Fiorella D , Derdeyn C , Turk A , Boulos A , Diaz O , Pride G , Jabbour P , Woo H
Published: July 2014

Introduction

The Low-profile Visualised Intraluminal Support (LVIS) Device is a novel, braided, intracranial microstent designed for stent-assisted coiling. We present the results of a single-arm, prospective, multicenter trial of the LVIS for the treatment of wide-necked intracranial aneurysms

Methods

31 patients with unruptured, wide-necked (neck >4 mm or dome : neck ratio <2) intracranial aneurysms were treated with the LVIS device and bare platinum coils at 6 US centers (IDE G110014). Clinical follow was conducted at 30d and 6 months. Angiographic follow up was performed at 6 months. The primary safety endpoint was any major stroke or death within 30 days or major ipsilateral stroke or neurological death within 6 months. Probable benefit was defined as >90% angiographic occlusion at 6 months. An independent core lab adjudicated angiographic results. An independent clinical events committee adjudicated clinical endpoints.

Results

Average aneurysm size was 7.2 mm (STD 3.8) and average neck width was 4.6 mm (STD 3.1). 68% of patients had a dome: neck ratio >2. LVIS placement was technically successful in 29 of 31 patients (93.5%). No primary safety endpoints occurred during the study (0%). No patient had a higher modified Rankin Score at 6 months when compared to baseline. 26 of 28 (92.9%) treated aneurysms with 6 month angiographic follow-up demonstrated >90% angiographic occlusion. Of these, 21 (75%) were completely occluded at follow up.

Conclusions

The LVIS device facilitated the coil-embolization of wide-necked intracranial aneurysms with high rates of technical success, an excellent safety profile and very high rates of complete and near complete occlusion at follow up.

Disclosures

D. Fiorella: 1; C; Microvention/Terumo, Sequent Medical, NIH, Siemens Medical Imaging. 2; C; JNJ/Codman, ev3/Covidien. 4; C; Vascular Simulations, CVSL. C. Derdeyn: 1; C; Terumo/Microvention. A. Turk: None. A. Boulos: None. O. Diaz: None. G. Pride: None. P. Jabbour: None. H. Woo: None.
P-009 WEB Endovascular Treatment of Wide-neck Bifurcation Aneurysms: Short- and Midterm Results in a European Study
Authors: Pierot L , Klisch J , Gauvrit J , Szikora I , Leonardi M , Liebig T , Nunzi N , Boccardi E , Di Paola F , Holtmanspötter M , Weber W , Calgliari E , Lubicz B
Published: July 2014

Background and purpose

Flow disruption with the WEB-DL device has been used safely for the treatment of wide-necked bifurcation aneurysms but the stability of aneurysm occlusion after this treatment is unknown. This retrospective multicenter European study analyzed short- and midterm data in patients treated with WEB-DL.

Methods

Twelve European neurointerventional centers participated to the study. Clinical data, pre- and post-operative, short-, and midterm images were collected. An experienced interventional neuroradiologist independently analyzed images. Aneurysm occlusion was classified in 4 grades: complete occlusion, opacification of the proximal recess of the device, neck remnant, and aneurysm remnant.

Results

Forty-five patients (34 females and 11 males) aged 35 to 74 years (mean: 56.3 +/- 9.6 years) harbouring 45 aneurysms treated with the WEB device were included. Aneurysm locations were middle cerebral artery in 26 patients, posterior circulation in 13, anterior communicating artery in 5, and internal carotid artery terminus in 1. Forty-two aneurysms were unruptured. Good clinical outcome (mRS < 2) was observed in 93.3% of patients. Adequate occlusion (Complete occlusion, opacification of the proximal recess, or neck remnant) was observed in 30/37 patients (81.1%) in short-term follow-up (median 6 months) and in 26/29 patients (89.7%) in midterm follow-up (median 13 months). Worsening of aneurysm occlusion was observed in 2/28 patients (7.1%) in midterm follow-up.

Conclusions

The results suggest WEB treatment of wide-neck bifurcation aneurysms offers stable occlusion in aneurysms that are usually unstable. Additionally, our data show that opacification of the WEB recess can be delineated from true neck or aneurysm remnant.

Disclosures

L. Pierot: 2; C; Sequent. J. Klisch: None. J. Gauvrit: None. I. Szikora: None. M. Leonardi: None. T. Liebig: None. N. Nunzi: None. E. Boccardi: None. F. Di Paola: None. M. Holtmanspötter: None. W. Weber: None. E. Calgliari: None. B. Lubicz: None.
E-002 Efficacy of the Pipeline Embolization Device in the Treatment of Previously-treated Aneurysms
Authors: Park M , Nanaszko M , Sanborn M , Moon K , McDougall C , Albuquerque F
Published: July 2014

Introduction

The Pipeline Embolization Device (PED, eV3 Neurovascular, Irvine, California) has increased the ability of the neurointerventionalist to treat progressively more difficult cerebrovascular pathology. We sought to determine the efficacy of the PED in the treatment of the most recalcitrant of aneurysms, those aneurysms recurring after previous treatments.

Materials and methods

We retrospectively queried a prospectively maintained endovascular database for previously treated cerebral aneurysms undergoing intervention with the PED from May 2011 to the present time. Twenty-two patients (4 male, 18 female; age range 30–78 yrs, average 59.3 yrs) were treated for 23 aneurysms (average size 11.9 mm, SD 8.5 mm) requiring 29 PED (average 1.3 PED/pt) during the study period. Fourteen patients were originally treated with neuro-interventional procedures (6 coil Embolization, 7 stent assisted coil Embolization, 1 stent only), whereas, eight patients were originally treated with open surgery (7 clipping, 1 wrapping). Of the eight clip recurrences, two patients had an additional neuro-interventional treatment with subsequent recurrence prior to PED use. Average length of follow-up was 8.5 months.

Results

The overwhelming majority of all patients in our cohorts had their final angiographic outcomes rated as improved (20 Better, 2 Same, 0 Worse) compared to the pre-procedure state. Furthermore, 11 patients had final Raymond scores of 1 and 11 patients had final Raymond scores of 2. There were no final Raymond 3 angiographic results in the series. Those patients who recurred following initial endovascular treatment had better final Raymond scores when compared to the open surgery cohort (9 of 14 Raymond 1 scores versus 2 of 8 Raymond 1 scores).

Conclusions

In our single center series, PED use for the treatment of recurrent aneurysms is an effective means of treating this difficult subset of patients. We observed that the vast majority of these patients will go on to have excellent angiographic outcomes following PED placement. Further investigations are needed to better elucidate the role of the PED in this cohort.

Disclosures

M. Park: None. M. Nanaszko: None. M. Sanborn: None. K. Moon: None. C. McDougall: None. F. Albuquerque: None.
E-012 National Trends for the Utilization of Cerebral Angiography in Patients with Unruptured Aneurysms: 1999–2009
Authors: Choudhri O , Feroze A , Mantha A , Steinberg G , Do H
Published: July 2014

Introduction

The utilization of cerebral angiography in the diagnosis and management of patients with unruptured cerebral aneurysms varies across the United States. Given advances in noninvasive imaging, such as CT and MR angiography, patients with unruptured aneurysms may never undergo cerebral angiography. This study explores shifting trends in the utilization of angiography for management of such lesions across the U. S. from 1999–2009.

Methods

The National Inpatient Sample was used to identify patients carrying a primary ICD-9 diagnosis code of unruptured aneurym (430.0) between 1999–2009. The primary outcomes were compared across subgroups undergoing cerebral angiography in the management of their pathology versus those who did not. The data were analyzed using univariate and multivariate regression (SAS).

Results

There were 127579 total admissions with a primary ICD-9 diagnosis of unruptured aneurysms between 1999–2009 per NIS weighted estimates. The total number of patients who underwent cerebral angiography and subsequent clipping were 19412 between 1999–2009. During the same time period 28095 patients underwent coiling after cerebral angiography. For the year 1999, 77% patients were clipped and 23% coiled after cerebral angiography (p < 0.0001). Conversely for the year 2009, 29% patients were clipped and 71% coiled after cerebral angiography (p < 0.0001). These trends were less pronounced though significant in the patients who did not undergo initial cerebral angiography, such that for the year 1999, 88% patients with unruptured aneurysms were clipped while only 12% were coiled.

Conclusions

Patients with unruptured cerebral aneuryms who undergo cerebral angiography are more likely to undergo endovascular coiling rather than clipping.

Disclosures

O. Choudhri: None. A. Feroze: None. A. Mantha: None. G. Steinberg: None. H. Do: None.
O-008 The Financial Impact of ADAPT for Endovascular Treatment of Acute Ischemic Stroke
Authors: Turk A , Turner R , Chaudry M , Spiotta A
Published: July 2014

Introduction

The use of mechanical thrombectomy for treatment of acute ischemic stroke has significantly advanced over the last 5 years. Little data is available analysing the cost relative to the clinical and angiographic outcomes. The aim of this study is to analyze the cost and efficacy of current stroke therapy.

Methods

A retrospective review of the chart and hospital financial database of all ischemic stroke cases from 2009–2013 was performed. Three discreet treatment methodologies evolved during this time: traditional Penumbra System (PS), stent retriever with local aspiration (SRLA) and A Direct Aspiration first Pass Technique (ADAPT). Statistical analysis of clinical and angiographic outcomes and costs for each group was performed.

Results

222 patients (45% male) underwent mechanical thrombectomy, with 88% of strokes present in the anterior circulation. PS was used 58%, SRLA 13% and ADAPT in the remaining 29% of cases. PS was able to achieve TICI2b/3 revascularization 79%, SRLA was effective 83% and ADAPT 95% of the time. The average total cost of hospitalization for patients treated with PS was $51,599, SRLA was $54,700 and ADAPT $33,611 (p < 0.0001). The average length of stay was significantly less for ADAPT (7 days) than PS (10.6 days), but not for SLRA (8.3 days) (p = 0.02). Average time to recanalization for PS was 88 min, SRLA was 47 min and ADAPT was 37 min (p < 0.0001). Similar rates of good neurologic outcomes were seen in group PS (36%) as group SRLA (43%) and ADAPT (47%) (p = 0.4).

Conclusion

The most cost effective approach to a large intracranial vessel occlusion appears to be direct aspiration with a large bore catheter (without the separator) first and if this fails then proceed with other devices such as a stentriever.

Disclosures

A. Turk:1; C; Stryker, Microvention, Penumbra. 2; C; Stryker, Microvention, Covidien, Penumbra, Siemens. 3; C; Stryker, Microvention, Covidien, Siemens, Penumbra. R. Turner: 1; C; Penumbra, Microvention, Stryker. 2; C; Penumbra, Microvention, Stryker. 3; C; Penumbra, Microvention, Stryker. M. Chaudry: 1; C; Penumbra, Microvention, Stryker. 2; C; Penumbra, Microvention, Stryker. 3; C; Penumbra, Microvention, Stryker. A. Spiotta: 1; C; Penumbra, Microvention, Stryker. 2; C; Penumbra, Microvention, Stryker. 3; C; Penumbra, Microvention, Stryker.
E-020 Safety and Efficacy of the Pipeline Embolization Device in 100 Small Intracranial Aneurysms
Authors: Chalouhi N , Zanaty M , Whiting A , Yang S , Tjoumakaris S , Hasan D , Starke R , Hann MS , Hammer C , Kung D , Rosenwasser R , Jabbour P
Published: July 2014

Objective

Flow diverters are increasingly used for treatment of intracranial aneurysms. In most series, the PED was used for the treatment of large, giant, complex, and fusiform aneurysms. Little is known about the use of the PED in small aneurysms. The purpose of this study was to assess the safety and efficacy of the PED in small aneurysms (≤ 7 mm).

Methods

A total of 100 consecutive patients with small aneurysms (≤ 7 mm) were treated with the PED at our institution between May 2011 and September 2013. Data on procedural safety and efficacy was retrospectively collected.

Results

Mean aneurysm size was 5.2 ± 1.5 mm. Seven patients had sustained a subarachnoid haemorrhage. All except 5 aneurysms (95%) arose from the anterior circulation. The number of PEDs used was 1.2 per aneurysm. Symptomatic procedure-related complications occurred in 3 (3%) patients: 1 distal parenchymal haemorrhage managed conservatively and 2 ischemic events. At the latest follow-up (mean, 6.1 months), 52 (71%) aneurysms were completely occluded (100%), 10 (14%) were near-completely occluded (≥90%), and 11 (15%) were incompletely occluded (<90%). Six aneurysms (8%) required further treatment. Increasing aneurysm size (OR= 3.9; 95% CI: 0.99–15; p = 0.05) predicted retreatment. All patients achieved a favorable outcome (mRS 0–2) at follow-up.

Conclusion

In this study, treatment of small aneurysms with the PED was associated with low complication rates and high aneurysm occlusion rates. These findings suggest that the PED is a safe and effective alternative to conventional endovascular techniques for small aneurysms. Randomised trials with long-term follow up are necessary to determine the optimal treatment that leads to the highest rate of obliteration and best clinical outcomes.

Disclosures

N. Chalouhi: None. M. Zanaty: None. A. Whiting: None. S. Yang: None. S. Tjoumakaris: None. D. Hasan: None. R. Starke: None. S. Hann: None. C. Hammer: None. D. Kung: None. R. Rosenwasser: None. P. Jabbour: None.
E-023 Consecutive Endovascular Treatment of Ruptured Very Small (<3 mm) Anterior Communicating (ACom) Artery Aneurysms: A Single Center Experience
Authors: Asif K , Teleb M , Sattar A , Lazzaro M , Fitzsimmons B , Lynch J , Zaidat O
Published: July 2014

Background

The anterior communicating (ACom) artery is the most common location of cerebral aneurysms harbouring upto 30–37% of all treated aneurysms. Amongst all ruptured aneurysms, the proportion of patients with very small aneurysms ranges from 12–18%. Treatment of very small aneurysms (<3 mm) of the anterior communicating artery presents a unique set of challenges for both surgical as well as endovascular techniques.

Objective

To report the immediate and long-term clinical as well as radiographic outcomes of consecutive patients with ruptured very small anterior communicating artery (ACOM) aneurysms treated with endovascular technique.

Methods

A prospectively maintained single institution neuro-endovascular database was accessed to identify consecutive cases of very small (<3 mm) ruptured ACom aneurysms treated endovascularly between 2006 and 2013. Clinical, demographic, radiographic, and procedural data were retrospectively obtained through chart review.

Results

A cohort of 20 consecutive patients with ruptured very small (<3 mm) ACom artery aneurysms were treated endovascularly including 13 females and 7 males with a mean age of 58.4 ± 12.9 yrs. Average maximum aneurysm diameter was 2.66 (± 0.41) mm. Hunt-Hess grade 1–3 for 14 (70%) patients and 4 for 6 (30%) patients. Dome to neck ratio was less than 2 for 13 (65%) of the aneurysms. Four (20%) aneurysms were bilobed. Aneurysm projection was antero-superior in 11 (55%), antero-inferior in 6 (30%) and postero-superior in 3 (15%). Primary coiling was performed for 16 (80%) aneurysms and balloon assistance was used for 4 (20%). Complete aneurysm occlusion was achieved for 17 (85%) aneurysms and near complete for 3 (15%) aneurysms. There were no symptomatic peri-procedural complications. Intra-operative perforation (IOP) occurred in 2 (10%) patients without any clinical worsening or need for an external ventricular drain. Thromboembolic event (TEE) occurred in 1 (5%) patient without clinical worsening or new radiologic infarct. Median clinical follow up was 12 (± 14.1) months and median imaging follow up was 12 (± 18.4) months. There were no instances of re-bleeding during follow up. At the 3 month clinic follow up, modified Rankin scale was 6 for one patient related to anaplastic astrocytoma. Of all the surviving 19 patients, post treatment clinical status either improved or remained stable. Recanalization with a neck residual occurred in two (10%) aneurysms and both were retreated with additional primary coiling and stent assistance.

Conclusion

Endovascular treatment of very small ACom aneurysms can be performed with acceptable rates of complications and recanalization. Robust conclusions can be drawn only after further evaluation with larger number of patients and longer follow-up.

Disclosures

K. Asif: None. M. Teleb: None. A. Sattar: None. M. Lazzaro: None. B. Fitzsimmons: None. J. Lynch: None. O. Zaidat: None.
E-024 A Single-center Experience of Carotid Artery Stenting in Patients with Carotid Stenosis
Authors: Lee J
Published: July 2014

Background

Carotid artery stenting (CAS) has emerged as a potential alternative to endarterectomy and its clinical practise dramatically increased in many parts of the world. This study aims to determine the safety and post-procedural complication of carotid artery stenting at a single-center institution in Korea.

Patients and methods

We retrospectively analyzed all CAS procedures performed at our institution between March 2009 and February 2013.

Results

During the observation period, a total of 87 CAS procedures were attempted in 79 patients with stenoses of the internal carotid artery of which 66 (75.9%) were symptomatic and 21 (24.1%) were asymptomatic. The patient group comprised 69 men (87.3%) and 10 women (12.7%) with a mean age of 67.9 years (range, 49–83 years). Stents were successfully inserted in 85 (97.7%) cases. Post-procedural vascular events to discharge occurred in 10 patients (3 cases of cerebral hyperperfusion syndrome, 7 cases of ischemic stroke). Among 10 patients, death and a permanent severe neurologic deficit occurred in 3 patients with cerebral hyperperfusion syndrome and 1 patient with ischemic stroke.

Conclusions

Post-procedural death or a permanent severe neurologic deficit after CAS occurred due to mainly hyperperfusion syndrome in our study.

Disclosures

J. Lee: None.
E-025 Transorbital Carotid-Cavernous Fistula Embolization with Ruby Coils
Authors: Milburn J , Pansara A , Perry M , Vidal G , Eubanks B
Published: July 2014

Purpose

A carotid cavernous fistula (CCF) is an abnormal arteriovenous connexion between the internal carotid artery (ICA) or the external carotid artery (ECA) and the cavernous sinus. Symptoms range from benign ocular disturbances and cranial nerve palsies to severe or rapid vision loss and intracranial haemorrhage. Primary treatment options include transvenous or transarterial embolization. Coil embolization of the cavernous sinus is often a long procedure using many small diameter microcoils with high radiation doses. The purpose of this case is to illustrate the use of larger diameter (0.020 inch) Ruby coils (Penumbra Inc.) as a highly efficient alternative method of embolization.

Methods

An 84-year-old woman presented to her local emergency room for progressive diplopia and loss of visual acuity over several weeks. Computed tomography (CT) of the head and CT angiography (CTA) revealed enlarged superior ophthalmic veins suggesting a CCF. Cerebral angiography was performed demonstrating an indirect CCF supplied by small branches of both the right and left internal and external carotid arteries with primary venous drainage into the right superior ophthalmic vein. Transvenous treatment from the femoral approach at the same setting was unsuccessful due to complete occlusion of the inferior petrosal sinus (IPS) bilaterally.

Definitive treatment was then performed via direct transorbital approach. An oculoplastic surgeon provided direct surgical exposure to the right superior ophthalmic vein. The neurointerventionalist then punctured the exposed vein with a micropuncture needle to advance a 4-French short sheath. A Penumbra PX SLIM microcatheter was then advanced to the posterior cavernous sinus at the midline. 7 Ruby coils were deployed into the cavernous sinus and right SOV to occlude the CCF. Occlusion of the CCF was achieved by deployment of 150 cm of Penumbra 0.020-inch calibre detachable coils. Procedure time was 21 min from introduction of the 1stcoil to microcatheter removal.

Results

Complete occlusion of the CCF was demonstrated on the final right and left common carotid angiograms. Her visual acuity improved on postoperative day 1. At her 1 week clinic visit, visual acuity was nearly at baseline, proptosis was improved, and diplopia improved. Her 6thnerve palsy was 50% improved on the 3 month follow-up.

Conclusion

Embolization of an indirect CCF may be performed efficiently using large diameter Ruby coils. This case presentation illustrates a direct transorbital approach via the SOV with operative photographs and pertinent angiographic images. The coil time was short due to the efficiency of the large (0.020 inch) diameter and long available lengths of Ruby coils.

Disclosures

J. Milburn: 3; C; Penumbra, Inc.. A. Pansara: None. M. Perry: None. G. Vidal: 3; C; Penumbra, Inc., Covidien. B. Eubanks: None.
Three-membered ring amides — a calculational and conceptual study of the structure and energetics of 1,2-oxaziridine-3-one and aziridine-2,3-dione
Authors: Miranda Margarida S. , Ferreira Paulo J.O. , Esteves da Silva Joaquim C.G. , Liebman Joel F.
Published: July 2014

Species with three-membered rings and the amide linkage are well studied. A quick perusal of the literature with SciFinder finds some 50 000 references to cyclopropanes and almost 300 000 references to amides. In the current paper, we discuss the structure and energetics of two understudied three-membered ring amides, 1,2-oxaziridine-3-one (5) (simultaneously describable as the simplest cyclic carbamate and simplest hydroxamate) and aziridine-2,3-dione (7) (simultaneously describable as the simplest imide and simplest α-ketoamide), with but 5 and nearly 10 references, respectively, for these two classes of compounds. Neither 1,2-oxaziridine-3-one (5) nor aziridine-2,3-dione (7), nor any derivative thereof, has been isolated. Calculational theory ameliorates the paucity of experimental information. The current study reports our computational findings for these and related species (e.g., enols and imidols) where we have used the G3(MP2)//B3LYP method.
Opinions on strategies for forest adaptation to future climate conditions in western Canada: surveys of the general public and leaders of forest-dependent communities
Authors: Hajjar Reem , McGuigan Erin , Moshofsky Molly , Kozak Robert A.
Published: July 2014

Two province-wide surveys of residents in Alberta and British Columbia were conducted to assess the acceptability of a range of reforestation strategies — many of which revolve around biotechnology — that could be used to aid western Canada’s forests in adapting to future climate change. The opinions of leaders of forest-dependent communities were also sought to evaluate how well they align with those of the public at large. Results show that the views of the general public and community leaders correspond. There is a low acceptance for a “do-nothing” strategy that allows climate change to run its course without any human intervention; high acceptance of replanting with local seeds; a decreasing acceptance of strategies that involve more manipulation such as breeding, using nonlocal seeds, and moving seeds outside of a species’ natural range; and a low acceptance of genetically engineered solutions. However, a high proportion of respondents changed their answers when told that a particular strategy would lead to either favourable or unfavourable outcomes related to socioeconomics of forest-dependent communities, forest aesthetics, and pest, disease, and fire outbreaks. We conclude that a meaningful and participatory dialogue on forest adaptation strategies in the face of climate change can only emerge if residents and other interested stakeholders have an adequate understanding of current forest management practices, proposed reforestation strategies, the role of technological interventions, and the values and services for which western Canada’s forests are to be managed.
Antipredator vigilance decreases with food density in staging flocks of Semipalmated Sandpipers (Calidris pusilla)
Authors: Beauchamp G.
Published: July 2014

When animals face time constraints, antipredator vigilance is expected to decrease in patches with higher food density. Indeed, sacrifices in safety are worthwhile in rich food patches that allow substantial foraging gains in response to a decrease in vigilance. This prediction has received little empirical attention. I tested this prediction in fall-staging Semipalmated Sandpipers (Calidris pusilla (L., 1766)) using the frequency of looks while foraging as a proxy for vigilance. Fall-staging sandpipers face time constraints, as individuals must accumulate fat rapidly before undertaking their long migration south. Controlling for known correlates of vigilance, such as distance to obstructive cover, bird density, and position in the flock, the frequency of looks decreased as predicted when the density of food in a patch was higher. That vigilance can vary with food density is relevant for observational studies of vigilance. When food density is positively correlated with group size, food density can become a confounding factor in the well-known negative relationship between vigilance and group size.
Wormholes and entanglement in holography
Authors: Jensen Kristan , Sonner Julian
Published: July 2014

In this paper, we consider highly entangled states in theories with a gravity dual, where the entangled degrees of freedom are causally disconnected from each other. Using the basic rules of holography, we argue that there is a nontraversable wormhole in the gravity dual whose geometry encodes the pattern of the entanglement.
On Random Sampling Auctions for Digital Goods
Authors: Alaei Saeed , Malekian Azarakhsh , Srinivasan Aravind
Published: July 2014

In the context of auctions for digital goods, an interesting random sampling auction has been proposed by Goldberg et al. [2001]. This auction has been analyzed by Feige et al. [2005], who have shown that it obtains in expectation at least 1/15 fraction of the optimal revenue, which is substantially better than the previously proven constant bounds but still far from the conjectured lower bound of 1/4. In this article, we prove that the aforementioned random sampling auction obtains at least 1/4 fraction of the optimal revenue for a large class of instances where the number of bids above (or equal to) the optimal sale price is at least 6. We also show that this auction obtains at least 1/4.68 fraction of the optimal revenue for the small class of remaining instances, thus leaving a negligible gap between the lower and upper bound. We employ a mix of probabilistic techniques and dynamic programming to compute these bounds.
Privacy Auctions for Recommender Systems
Authors: Dandekar Pranav , Fawaz Nadia , Ioannidis Stratis
Published: July 2014

We study a market for private data in which a data analyst publicly releases a statistic over a database of private information. Individuals that own the data incur a cost for their loss of privacy proportional to the differential privacy guarantee given by the analyst at the time of the release. The analyst incentivizes individuals by compensating them, giving rise to a
privacy
auction
. Motivated by recommender systems, the statistic we consider is a linear predictor function with publicly known weights. The statistic can be viewed as a prediction of the unknown data of a new individual, based on the data of individuals in the database. We formalize the trade-off between privacy and accuracy in this setting, and show that a simple class of estimates achieves an order-optimal trade-off. It thus suffices to focus on auction mechanisms that output such estimates. We use this observation to design a truthful, individually rational, proportional-purchase mechanism under a fixed budget constraint. We show that our mechanism is 5-approximate in terms of accuracy compared to the optimal mechanism, and that no truthful mechanism can achieve a 2 − 
ε
approximation, for any
ε
 > 0.
Extending shared hypermedia workspaces to face-to-face multitouch experiences
Authors: Rubart Jessica
Published: July 2014

Shared hypermedia workspaces provide cooperative access to and manipulation of emergent shared hypermedia structures. Most such workspace approaches focus on distributed users. We are currently extending shared hypermedia workspaces for distributed users with face-to-face multitouch experiences. Our approach applies multitouch single display groupware to shared hypermedia workspaces. As an application scenario we have selected the Scrum planning approach to software development. Scrum task boards are handled like shared hypermedia workspaces. We present a cooperative multitouch Scrum task board.
Upcoming SIGWEB supported conferences
Authors: Samuel Hamman
Published: July 2014

The Special Interest Group on Hypertext and the Web, SIGWEB was created in 1989 to support the community participating in the annual ACM Hypertext Conference. Now in its third decade, SIGWEB has grown considerably and now sponsors five annual conferences of different sizes and covering a wide range of topics. SIGWEB supports several specialized conferences, short courses, and workshops, as well as the Annual Hypertext Conference. SIGWEB sponsored conferences focus on timely topics in applied and computational hypertext and Web disciplines and provide a place for members and the entire applied Hypermedia and Web community to exchange ideas and to meet with and expand their network of colleagues. In this article, we provide a brief overview of SIGWEB sponsored conferences, in addition to events that are in cooperation with SIGWEB.
Optimizing hyperspace hashing via analytical modelling and adaptation
Authors: Diegues Nuno , Orazov Muhammet , Paiva João , Rodrigues Luís , Romano Paolo
Published: July 2014

Hyperspace hashing is a recent multi-dimensional indexing technique for distributed key-value stores that aims at supporting efficient queries using multiple objects' attributes. However, the advantage of supporting complex queries comes at the cost of a complex configuration. In this paper we address the problem of automating the configuration of this innovative distributed indexing mechanism. We first show that a misconfiguration may significantly affect the performance of the system. We then derive a performance model that provides key insights on the behaviour of hyperspace hashing. Based on this model, we derive a technique to automatically and dynamically select the best configuration.
Cloudsweeper and data-centric security
Authors: Snyder Peter , Kanich Chris
Published: July 2014

Most security online is binary, where being authorized to access a system allows complete access to the requested resource. This binary system amplifies the harm of giving access to an unauthorized individual and motivates system designers to strengthen access control mechanisms to the point where they become so strong as to be nearly insurmountable for illegitimate and legitimate users alike.

As a result, Internet users are required to jump through several hoops to access their data: ever longer passwords, multiple authentication factors, or time consuming CAPTCHAs. Users must always provide strong proof of their identity, regardless of whether they want to check their email for something as innocuous as a movie time or as serious as a medical test result. Not surprisingly, users often disable or refuse to use these tedious security options [2, 5, 7].

Users may be better served by a
data-centric
approach to security, where systems are sensitive to the differing security needs of data, even within a single account or collection. A data-centric approach can apply strong security only when the data being protected warrants it, while allowing users a less encumbered experience the majority of the time. Machine learning techniques can automate the detection of sensitive information, freeing users from the tedious task of sorting their data into low and high security categories. With less friction involved in securing their data, users may be more likely to use strong security where available, resulting in a more secure Internet for everyone.

We present
Cloudsweeper
, a tool that applies a data-centric approach to security to the specific case of plain text password sharing in Gmail accounts. Cloudsweeper detects and applies an additional layer of encryption to plain text passwords in a user's email account, while allowing the user to access the rest of their email archive as normal. Public use of Cloudsweeper shows that such a data-centric approach to securing data can be an effective way of providing users more security while still being acceptably convenient.
Ethics in context
Authors: Heron Michael James , Belford Pauline
Published: July 2014

The delivery of ethical instruction within formal educational contexts is a task that is fraught with difficulties. Real world situations and examples of misconduct abound, but sourcing sufficient material within the constraints associated with developing course materials can be time-consuming. The availability of resources to illustrate relevant aspects may not be available, or may not fully emphasize the issues that educators wish to incorporate into their discussion of the material. At best, such an approach can only highlight in isolation - larger, overarching connections are rarely available. The provision of ethical instruction is now a core aspect of many undergraduate and postgraduate courses across a variety of disciplines, and accreditation bodies often include meeting the need for instruction in ethical and professional issues as a pre-requisite. In this paper we present a wide-ranging ethical case study called 'A Scandal in Academia'. It is a spiritual successor to the Case of the Killer Robot first published in the very early 1990s. The Scandal in Academia study has been trialed with students at all levels of the undergraduate curriculum and has been very effective in offering a coherent jumping-off point for a discussion of the implications of ethical and unethical activity. It is hoped that the provision of this study will be a useful tool for educators and others looking to investigate and present issues of professional responsibility within formal and informal contexts.
Sustained mitochondrial functioning in cerebral arteries after transient ischemic stress in the rat: a potential target for therapies
Authors: Rutkai Ibolya , Katakam Prasad V. G. , Dutta Somhrita , Busija David W.
Published: July 2014

The objective of the present study was to determine whether mitochondrial function in the cerebral vasculature is maintained after transient middle cerebral artery (MCA) occlusion (tMCAO) in rats. Sprague-Dawley rats were exposed to 90 min of tMCAO followed by 4 or 48 h of reperfusion. MCAs from ischemic (ipsilateral) and nonischemic (contralateral) sides were compared with control MCAs from sham-operated rats. We determined 1) vasoreactivity to diazoxide (DZ; a mitochondrial ATP-activated K+ channel opener), ACh, bradykinin (BK), serotonin, and sodium nitroprusside; 2) levels of mitochondrial and nonmitochondrial proteins and mitochondrial DNA; and 3) vascular levels of tetramethylrhodamine ethyl ester (an indicator of mitochondrial membrane potential). All dilator responses, including those with DZ, were intact 4 h post-tMCAO. Dilator responses to ACh, BK, and sodium nitroprusside were reduced in ipsilateral MCAs at 48 h compared with contralateral MCAs, but DZ responses were comparable with control MCAs. Surprisingly, contralateral responses to ACh, BK, and serotonin were reduced compared with control MCAs at 48 h. Ipsilateral vasodilation to DZ at 48 h was eliminated by endothelial denudation and endothelial nitric oxide synthase (eNOS) inhibition but was only reduced in control MCAs. Mitochondrial proteins, phosphorylated eNOS, mitochondrial DNA, and mitochondrial membrane potential were higher in ipsilateral compared with contralateral MCAs. In conclusion, contrary to conventional wisdom, mitochondria remain functional for at least 48 h after severe ischemic stress in MCAs, and DZ-induced dilation is preserved due to maintained mitochondrial mass, probably in the endothelium, and eNOS signaling. Our findings support the concept that functioning vascular mitochondria are an unexpected target for novel stroke therapies.
Low Folate Levels Are Associated with Reduced Risk of Colorectal Cancer in a Population with Low Folate Status
Authors: Gylling Björn , Van Guelpen Bethany , Schneede Jörn , Hultdin Johan , Ueland Per Magne , Hallmans Göran , Johansson Ingegerd , Palmqvist Richard
Published: July 2014

Background: A diet rich in folate is associated with a reduced colorectal cancer risk, whereas the role of circulating levels is less clear. The aim of this study was to relate prediagnostic plasma folate, vitamin B12, and homocysteine concentrations to the risk of colorectal cancer.

Methods: This was a prospective case–control study of 331 cases and 662 matched controls nested within the population-based Northern Sweden Health and Disease Study. Median follow-up time from recruitment to diagnosis was 10.8 years.

Results: Plasma folate concentrations were positively related to colorectal cancer risk; multivariate odds ratios were 1.62 [95% confidence intervals (CI), 1.08–2.42] and 1.42 (95% CI, 0.94–2.21) for the middle and highest versus lowest tertile, respectively. In subjects with follow-up <10.8 years, a statistically significant doubled risk was observed for the middle and highest versus lowest tertile, whereas findings for longer follow-up times were null. A positive risk relationship was also observed for tumor stage III–IV but not I–II. Plasma vitamin B12 concentrations were inversely associated with rectal cancer risk. Homocysteine was not significantly related to colorectal cancer risk.

Conclusions: In this population-based, nested case–control study, low plasma folate concentrations were associated with a reduced colorectal cancer risk. This protective role was mainly observed in subjects with higher tumor stage or shorter follow-up time between recruitment and diagnosis. Low circulating folate status may protect against colorectal cancer or suppress progression of preneoplastic or neoplastic lesions.

Impact: These findings may have relevance for the ongoing debate about mandatory folic acid fortification of flour. Cancer Epidemiol Biomarkers Prev; 23(10); 2136–44. ©2014 AACR.
Tumor-Based Case–Control Studies of Infection and Cancer: Muddling the When and Where of Molecular Epidemiology
Authors: Engels Eric A. , Wacholder Sholom , Katki Hormuzd A. , Chaturvedi Anil K.
Published: July 2014

We describe the “tumor-based case–control” study as a type of epidemiologic study used to evaluate associations between infectious agents and cancer. These studies assess exposure using diseased tissues from affected individuals (i.e., evaluating tumor tissue for cancer cases), but they must utilize nondiseased tissues to assess control subjects, who do not have the disease of interest. This approach can lead to exposure misclassification in two ways. First, concerning the “when” of exposure assessment, retrospective assessment of tissues may not accurately measure exposure at the key earlier time point (i.e., during the etiologic window). Second, concerning the “where” of exposure assessment, use of different tissues in cases and controls can have different accuracy for detecting the exposure (i.e., differential exposure misclassification). We present an example concerning the association of human papillomavirus with various cancers, where tumor-based case–control studies likely overestimate risk associated with infection. In another example, we illustrate how tumor-based case–control studies of Helicobacter pylori and gastric cancer underestimate risk. Tumor-based case–control studies can demonstrate infection within tumor cells, providing qualitative information about disease etiology. However, measures of association calculated in tumor-based case–control studies are prone to over- or underestimating the relationship between infections and subsequent cancer risk. Cancer Epidemiol Biomarkers Prev; 23(10); 1959–64. ©2014 AACR.
Discovery-Based Protein Expression Profiling Identifies Distinct Subgroups and Pathways in Leiomyosarcomas
Authors: Kirik Ufuk , Hansson Karin , Krogh Morten , Jönsson Mats , Nilbert Mef , James Peter , Carneiro Ana
Published: July 2014

Soft tissue sarcomas (STS) are malignant tumors of mesenchymal origin. A substantial portion of these tumors exhibits complex karyotypes and lack characterized chromosomal aberrations. Owing to such properties, both histopathologic and molecular classification of these tumors has been a significant challenge. This study examines the protein expression of a large number of human STS, including subtype heterogeneity, using two-dimensional gel proteomics. In addition, detailed proteome profiles of a subset of pleomorphic STS specimens using an in-depth mass-spectrometry approach identified subgroups within the leiomyosarcomas with distinct protein expression patterns. Pathways analysis indicates that key biologic nodes like apoptosis, cytoskeleton remodeling, and telomere regulation are differentially regulated among these subgroups. Finally, investigating the similarities between protein expression of leiomyosarcomas and undifferentiated pleomorphic sarcomas (UPS) revealed similar protein expression profiles for these tumors, in comparison with pleomorphic leiomyosarcomas.

Implications: These results suggest that UPS tumors share a similar lineage as leiomyosarcomas and are likely to originate from different stages of differentiation from mesenchymal stem cells to smooth muscle cells. Mol Cancer Res; 12(12); 1729–39. ©2014 AACR.
Targeted Deletion and Lipidomic Analysis Identify Epithelial Cell COX-2 as a Major Driver of Chemically Induced Skin Cancer
Authors: Jiao Jing , Ishikawa Tomo-O , Dumlao Darren S. , Norris Paul C. , Magyar Clara E. , Mikulec Carol , Catapang Art , Dennis Edward A. , Fischer Susan M. , Herschman Harvey R.
Published: July 2014

Pharmacologic and global gene deletion studies demonstrate that cyclooxygenase-2 (PTGS2/COX-2) plays a critical role in DMBA/TPA–induced skin tumor induction. Although many cell types in the tumor microenvironment express COX-2, the cell types in which COX-2 expression is required for tumor promotion are not clearly established. Here, cell type–specific Cox-2 gene deletion reveals a vital role for skin epithelial cell COX-2 expression in DMBA/TPA tumor induction. In contrast, myeloid Cox-2 gene deletion has no effect on DMBA/TPA tumorigenesis. The infrequent, small tumors that develop on mice with an epithelial cell–specific Cox-2 gene deletion have decreased proliferation and increased cell differentiation properties. Blood vessel density is reduced in tumors with an epithelial cell–specific Cox-2 gene deletion, compared with littermate control tumors, suggesting a reciprocal relationship in tumor progression between COX-2–expressing tumor epithelial cells and microenvironment endothelial cells. Lipidomics analysis of skin and tumors from DMBA/TPA–treated mice suggests that the prostaglandins PGE2 and PGF2α are likely candidates for the epithelial cell COX-2–dependent eicosanoids that mediate tumor progression. This study both illustrates the value of cell type–specific gene deletions in understanding the cellular roles of signal-generating pathways in complex microenvironments and emphasizes the benefit of a systems-based lipidomic analysis approach to identify candidate lipid mediators of biologic responses.

Implications: Cox-2 gene deletion demonstrates that intrinsic COX-2 expression in initiated keratinocytes is a principal driver of skin carcinogenesis; lipidomic analysis identifies likely prostanoid effectors. Mol Cancer Res; 12(11); 1677–88. ©2014 AACR.