bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cross-Correlations and Joint Gaussianity in Multivariate Level Crossing Models
Authors: Di Bernardino Elena , León José , Tchumatchenko Tatjana 
Published: April 2014

Abstract
A variety of phenomena in physical and biological sciences can be mathematically understood by considering the statistical properties of level crossings of random Gaussian processes. Notably, a growing number of these phenomena demand a consideration of correlated level crossings emerging from multiple correlated processes. While many theoretical results have been obtained in the last decades for individual Gaussian level-crossing processes, few results are available for multivariate, jointly correlated threshold crossings. Here, we address bivariate upward crossing processes and derive the corresponding bivariate Central Limit Theorem as well as provide closed-form expressions for their joint level-crossing correlations.
Assessment of ventilation inhomogeneity during mechanical ventilation using a rapid-response oxygen sensor-based oxygen washout method
Authors: Bikker Ido G , Holland Wim , Specht Patricia , Ince Can , Gommers Diederik 
Published: April 2014

Abstract

Purpose
Ventilatory inhomogeneity indexes in critically ill mechanically ventilated patients could be of importance to optimize ventilator settings in order to reduce additional lung injury. The present study compared six inhomogeneity indexes calculated from the oxygen washout curves provided by the rapid oxygen sensor of the LUFU end-expiratory lung volume measurement system.

Methods
Inhomogeneity was tested in a porcine model before and after induction of acute lung injury (ALI) at four different levels of positive end-expiratory pressure (PEEP; 15, 10, 5 and 0 cm H2O). The following indexes were assessed: lung clearance index (LCI), mixing ratio, Becklake index, multiple breath alveolar mixing inefficiency, moment ratio and pulmonary clearance delay.

Results
LCI, mixing ratio, Becklake index and moment ratio were comparable with previous reported values and showed acceptable variation coefficients at baseline with and without ALI. Moment ratio had the highest precision, as calculated by the variation coefficients. LCI, Becklake index and moment ratio showed comparable increases in inhomogeneity during decremental PEEP steps before and after ALI.

Conclusions
The advantage of the method we introduce is the combined measurement of end-expiratory lung volume (EELV) and inhomogeneity of lung ventilation with the LUFU fast-response medical-grade oxygen sensor, without the need for external tracer gases. This can be combined with conventional breathing systems. The moment ratio and LCI index appeared to be the most favourable for integration with oxygen washout curves as judged by high precision and agreement with previous reported findings. Studies are under way to evaluate the indexes in critically ill patients.
A systematic review of therapeutic hypothermia for adult patients following traumatic brain injury
Authors: Crossley Samantha , Reid Jenny , McLatchie Rachel , Hayton Judith , Clark Clair , MacDougall Margaret , Andrews Peter JD 
Published: April 2014

Abstract
Introduction
Research into therapeutic hypothermia following traumatic brain injury has been characterised by small trials of poor methodological quality, producing variable results. The Cochrane review, published in 2009, now requires updating. The aim of this systematic review is to assess the effectiveness of the application of therapeutic hypothermia to reduce death and disability when administered to adult patients who have been admitted to hospital following traumatic brain injury.

Methods
Two authors extracted data from each trial. Unless stated in the trial report, relative risks and 95% confidence intervals (CIs) were calculated for each trial. We considered P < 0 · 05 to be statistically significant. We combined data from all trials to estimate the pooled risk ratio (RR) with 95% confidence intervals for death, unfavourable outcome, and pneumonia. All statistical analyses were performed using RevMan 5.1 (Cochrane IMS, Oxford, UK) and Stata (Intercooled Version 12.0, StataCorp LP). Pooled RRs were calculated using the Mantel-Haenszel estimator. The random effects model of DerSimonian and Laird was used to estimate variances for the Mantel-Haenszel and inverse variance estimators.

Results
Twenty studies are included in the review, while 18 provided mortality data. When the results of 18 trials that evaluated mortality as one of the outcomes were statistically aggregated, therapeutic hypothermia was associated with a significant reduction in mortality and a significant reduction in poor outcome. There was a lack of statistical evidence for an association between use of therapeutic hypothermia and increased onset of new pneumonia.

Conclusions
In contrast to previous reviews, this systematic review found some evidence to suggest that therapeutic hypothermia may be of benefit in the treatment of traumatic brain injury. The majority of trials were of low quality, with unclear allocation concealment. Low quality trials may overestimate the effectiveness of hypothermia treatment versus standard care. There remains a need for more, high quality, randomised control trials of therapeutic hypothermia after traumatic brain injury.
PROSPERO Systematic Review Registration Number 2012:CRD42012002449.
Optic flow and sea - land orientation in the sandhopper Talitrus saltator (Montagu)
Authors: Ugolini Alberto 
Published: April 2014

Abstract
The problem sandhoppers face when they find themselves on the dry sand is to reach as quickly as possible the belt of moist sand near the water. Alongside many other orienting factors, here we ask whether sandhoppers use the optic flow they experience to maintain their bearing relative to the sea - land axis. Adult individuals of Talitrus saltator (Montagu) were released in a transparent Plexiglas bowl, horizontally placed between four walls carrying a pattern of vertical black and white stripes. The orientation of one pair of opposite walls was South - North, orthogonal to the sea - land axis of the home beach, whilst the second pair of walls was oriented East - West. The black and white stripes pattern of opposite walls could be moved in pairs and in the same direction (speed = 4.8 cm sec-1). The results demonstrate that the optic flow sandhoppers experience when moving on the sea - land axis of their home beach influences their direction of travel and could help sandhoppers in maintaining a straight path to reach favourable ground by the shortest route.
Novel underwater soundscape: acoustic repertoire of plainfin midshipman fish
Authors: McIver Eileen L. , Marchaterre Margaret A. , Rice Aaron N. , Bass Andrew H. 
Published: April 2014

AbstractToadfishes are among the best-known groups of sound producing (vocal) fishes and include species commonly known as toadfish and midshipman. Although midshipman have been the subject of extensive investigation of the neural mechanisms of vocalization, this is the first comprehensive, quantitative analysis of the spectro-temporal characters of their acoustic signals and one of the few for fishes in general. Field recordings of territorial, nest-guarding male midshipman during the breeding season identified a diverse vocal repertoire comprised of three basic sound types that varied widely in duration, harmonic structure, and degree of amplitude modulation (AM) - "hum", "grunt", and "growl". Hum duration varied nearly 1000 fold, lasting for minutes at a time, with stable harmonic stacks and little envelope modulation throughout the sound. By contrast, grunts were brief, ~30-140 ms, broadband signals produced both in isolation and repetitively as a train of up to 200 at intervals of ~0.5-1.0 s. Growls were also produced alone or repetitively, but at variable intervals on the order of seconds with durations between that of grunts and hums, ranging 60 fold from ~200 ms - 12 s. Growls exhibited prominent harmonics with sudden shifts in pulse repetition rate and highly variable AM patterns, unlike the nearly constant AM of grunt trains and flat envelope of hums. Behavioral and neurophysiological studies support the hypothesis that each sound type's unique acoustic signature contributes to signal recognition mechanisms. Nocturnal production of these sounds against a background chorus dominated constantly for hours by a single sound type, the multi-harmonic hum, reveals a novel underwater soundscape for fish.
Substituent Effects on the Geometries and Energies of the Antimony–Silicon Multiple Bond
Authors: Wen Xiang-Ting , Li Yu-Chi , Su Ming-Der 
Published: April 2014

Abstract
Substituent effects on the potential energy surface of XSiSb (X = H, Li, Na, BeH, MgH, BH2, AlH2, CH3, SiH3, NH2, PH2, OH, SH, F, and Cl) were investigated by using B3LYP/Def2-TZVP, B3PW91/Def2-TZVPP, and CCSD(T) methods. The isomers include structures with formal double (Si=SbX) and triple (XSi≡Sb) bonds to silicon–antimony, so a direct comparison of these types of species is possible. Our model calculations indicate that electropositively substituted Si=SbX species are thermodynamically and kinetically more stable than their isomeric XSi≡Sb molecules. Moreover, the theoretical findings suggest that F, OH, NH2, and CH3 substitutions prefer to shift the double bond (Si=SbX) by forming a triple bond (XSi≡Sb).
Systemic effects of polymethylmethycrylate in total knee replacement
Authors: Cheng K. , Giebaly D. , Campbell A. , Rumley A. , Lowe G. 
Published: April 2014

ObjectiveMortality rates reported by the National Joint Registry for England and Wales (NJR) were higher following cemented total knee replacement (TKR) compared with uncemented procedures. The aim of this study is to examine and compare the effects of cemented and uncemented TKR on the activation of selected markers of inflammation, endothelium, and coagulation, and on the activation of selected cytokines involved in the various aspects of the systemic response following surgery.MethodsThis was a single centre, prospective, case-control study. Following enrolment, blood samples were taken pre-operatively, and further samples were collected at day one and day seven post-operatively. One patient in the cemented group developed a deep-vein thrombosis confirmed on ultrasonography and was excluded, leaving 19 patients in this cohort (mean age 67.4, (sd 10.62)), and one patient in the uncemented group developed a post-operative wound infection and was excluded, leaving 19 patients (mean age 66.5, (sd 7.82)).ResultsBoth groups had a similar response with regards to the levels of C-reactive protein (CRP), interleukin 6 (IL-6) and tumour necrosis factor-alpha (TNFα). CD40 levels rose significantly on the cemented group over day one to day seven compared with that of the uncemented group, which occurred over the first 24 hours. The CD14/42a levels demonstrated a statistically significant increase in the cemented group (p < 0.001 first 24 hours and p = 0.02 between days one and seven).ConclusionsThe uncemented and cemented groups demonstrated significant changes in the various parameters measured at various time points but apart from CD14/42a levels, there was no significant difference in the serum markers of inflammation, coagulation and endothelial dysfunction following cemented TKR. Cite this article: Bone Joint Res 2014;3:108–16.
Combining Percutaneous Pedicular and Extrapedicular Access for Tumor Ablation in a Thoracic Vertebral Body
Authors: Cianfoni Alessandro , Massari Francesco , Ewing Stacey , Persenaire Maarten , Rumboldt Zoran , Bonaldi Giuseppe 
Published: April 2014

We present a percutaneous modified technique to access large thoracic vertebral body lytic lesions, to increase the volume of tumor accessible to ablation, prior to cement augmentation. Tumor ablation and cavity creation-assisted percutaneous vertebroplasty was considered a palliative measure for structural stabilization in plasmocytoma involvement of the entire T8 vertebral body. Given the extent of osteolysis bilateral combined transpedicular and extrapedicular access to the vertebral body was undertaken to maximize the volume of cavity creation within the tumor. The combined transpedicular and extrapedicular access was feasible, uncomplicated, and successful in reaching all the quadrants of the anterior two thirds of the vertebral body. Slow, fluoroscopically monitored injection of high-viscosity cement resulted in a successful, desired cement distribution into the anterior two thirds of the vertebral body, spanning superior to inferior endplates, providing structural stability, in the absence of venous or epidural leakage. The technical modification described in this case yielded positive results while overcoming some of the limitations of the existing coblation device. This approach may offer an option for cement augmentation of extensive vertebral body lytic lesions, at increased risk for tumor displacement and extra-vertebral cement leakage.
Fatal Avulsion of Choroidal or Perforating Arteries by Guidewires
Authors: Darsaut Tim E. , Costalat Vincent , Salazkin Igor , Jamali Sara , Berthelet France , Gevry Guylaine , Roy Daniel , Raymond Jean 
Published: April 2014

Innovations in endovascular tools have permitted an increasingly broad range of neurovascular lesions to be treated via minimally invasive methods. However, some device modifications may carry additional risks, not immediately apparent to operators. A patient with a symptomatic, partially thrombosed basilar apex aneurysm was allocated balloon-assisted coiling. Attempts were made to place a microwire across the basilar apex through the posterior communicating artery. Overlapping courses of the posterior cerebral and posterior choroidal arteries on the roadmap images were not recognized and a flanged-tip microwire was inadvertently advanced deep into the choroidal artery. Following the wire with a microcatheter led to binding of arterial tissue within the microcatheter. Removing the wire led to an avulsion of the choroidal artery and a severe hemorrhagic complication which proved fatal. Tissue was identified on the tip of the guidewire. Pathology showed layers of vascular tissue within the laser-cut flanges of the distal wire tip. A similar complication, also fatal, occurred during balloon angioplasty of a distal vertebral artery, when an exchange wire was accidently introduced into a perforator from a posterior cerebral artery. Ex vivo catheterization of distal mesenteric arterial branches showed that the wall of small arteries can be entrapped by laser-cut, flanged, but not by smooth guidewire tips. Microwires with a flanged instead of smooth distal tip, when placed into small caliber vessels, may cause hemorrhagic complications from avulsions.
Outcome Prediction in Acute Stroke Patients Considered for Endovascular Treatment: A Novel Tool
Authors: Grech Reuben , Galvin Patrick Leo , Power Sarah , O'Hare Alan , Looby Seamus , Brennan Paul , Thornton John 
Published: April 2014

Functional outcome following emergent intra-arterial thrombectomy is variable and likely reflects the heterogeneous characteristics of acute stroke patients. The aims of our study were (1) to study which pre-treatment variables correlate with functional outcome and (2) to devise a tool which would reliably predict outcome. Prospective data of patients treated with intra-arterial mechanical thrombectomy in our institution between 2010 and 2012 were collected. A preliminary univariate analysis of baseline variables was performed and data outliers were identified by constructing scatter and box plots. Systematic bivariate analysis was then carried out using a linear regression model and the individual contributing weights of the variables to outcome calculated. The B and constant values from the regression were used to construct a predictive formula. Fifty-seven patients, 35 males (61.4%) and 22 females (38.6%) with a mean age of 62.3 years (range 26–87) were included in the cohort. Statistical correlations of baseline variables and functional outcome showed that age, National Institutes of Health Stroke Scale at presentation and CT leptomeningeal collaterals were strongly correlated (p<0.01), and were later included in the linear regression model. A tool was devised from the regression formula combining weighted inputs of the three variables. Regression statistics and residual analysis were then performed to assess the accuracy and reliability of the proposed tool. The proposed tool is easy to use and reliably predicts functional outcome prior to endovascular therapy. It may help clinical decision-making in the acute setting and offers ‘tailor-made’ outcome expectations.
Intra-Arterial Therapy as a Rescue Strategy after Clinically Failed Intravenous Thrombolysis May Increase the Likelihood of a Good Outcome in Patients with Severe Ischaemic Stroke
Authors: Menetti Federico , Verganti Luca , Zini Andrea , Vallone Stefano , Carpeggiani Paolo , Andersson Tommy 
Published: April 2014

The purpose of this study was to evaluate the efficacy and safety of intra-arterial therapy as a rescue strategy after clinically failed intravenous thrombolysis (IVT) in acute ischaemic stroke patients. We conducted a retrospective analysis of consecutive acute ischaemic stroke patients treated with rescue therapy. The results from this study group were compared with those obtained from a control group consisting of 260 consecutive patients treated with IVT alone. The study group consisted of 52 patients with a mean age of 63 years and a median NIHSS score at admission of 17. Recanalization was achieved in 92% with a symptomatic haemorrhage rate of 9.6%. Rescue patients admitted with a severe stroke (NIHSS score >12) had a significantly better outcome at 90 days compared to patients with the same score but treated with IVT alone. No difference was seen for patients with a lower score at admission. This study indicates that rescue therapy may increase the proportion of patients with independent outcome if presenting with a severe stroke (NIHSS score >12) without increasing the rate of symptomatic haemorrhage.
Mechanical Thrombectomy versus Intrasinus Thrombolysis for Cerebral Venous Sinus Thrombosis: A Non-Randomized Comparison
Authors: Siddiqui Fazeel M. , Banerjee Chirantan , Zuurbier Susanna M. , Hao Qing , Ahn Chul , Pride Glenn L. , Wasay Muhammad , Majoie Charles B.L.M. , Liebeskind David , Johnson Mark , Stam Jan 
Published: April 2014

Small retrospective studies have shown the benefit of endovascular treatment with intrasinus thrombolysis (IST) or mechanical thrombectomy (MT) with/without IST (MT+/−IST) in cases of multifocal cerebral venous thrombosis (CVT). Our study compares the mortality, functional outcome and periprocedural complications among patients treated with MT +/– IST versus IST alone. We reviewed clinical and angiographic findings of 63 patients with CVT who received endovascular treatment at three tertiary care centers. Primary outcome variables were discharge mortality and neurological dysfunction, and intermediate (three months) and long-term (>six months) morbidity. The modified Rankin scale (mRS) was used to assess morbidity. mRS ≤1 was considered a good recovery. Neurological dysfunction was rated as neuroscore: 0, normal; 1, mild (ambulatory, communicative); 2, moderate (non-ambulatory, communicative); and 3, severe (non-ambulatory, non-communicative/comatose). In patients who received IST alone, presenting neurological deficits were comparatively minor (p<0.001). When the two groups were adjusted for admission neuroscore, there was no statistical significance between discharge mortality [7(21%) versus 4(14%), p=0.228], neurological dysfunction (p=0.442), intermediate (p=0.336) and long-term morbidity (p=0.988). Patients who received MT +/- IST had a higher percentage of periprocedural complications without reaching statistical significance. Compared to IST, MT was performed in severe cases with extensive sinus involvement. When adjusted for admission neurological dysfunction, both groups had similar mortality and discharge neurological dysfunction and similar intermediate and long-term morbidity.
Selective and Superselective Angiography of Pediatric Moyamoya Disease Angioarchitecture in the Posterior Circulation
Authors: Baltsavias Gerasimos , Khan Nadia , Filipce Venko , Valavanis Anton 
Published: April 2014

The anastomotic network of the posterior circulation in children with moyamoya disease has not been analyzed. We aimed to investigate the angiographic anatomy of this unique vascular network in patients with childhood moyamoya disease. Selective and superselective injections of the posterior circulation were performed in six children with newly diagnosed moyamoya disease. The arterial branches feeding the moyamoya anastomotic network, their connections and the recipient vessels were demonstrated. Depending on the level of the steno-occlusive lesion, the feeding vessels were the thalamoperforators, the posterior choroidals, the splenic artery, parietoccipital artery, other cortical posterior cerebral artery (PCA) branches, the dural branch of the PCA, the premamillary artery and other posterior communicating artery perforators. Through connections, which are described, the recipient vessels were the striate and medullary arteries, other thalamic arteries with or without medullary extensions, the pericallosal artery, medial parietoccipital cortical branches of the PCA and the anterior choroidal artery. High quality selective and superselective angiography helped in demonstrating the angiographic anatomy of the moyamoya posterior anastomotic network previously either vaguely or incompletely described, as well as connections within the posterior circulation but also its relevance as a collateral to the anterior circulation.
Use of the Pipeline Embolization Device to Treat Recently Ruptured Dissecting Cerebral Aneurysms
Authors: Chan Robert S.K. , Mak Calvin H.K. , Wong Alain K.S. , Chan Kwong Yau , Leung Kar Ming 
Published: April 2014

The Pipeline embolization device (PED) is one of the flow-diverting stents approved for the treatment of unruptured large or wide-necked cerebral aneurysms in 2011. Its use has now been extended to the treatment of recently ruptured dissecting cerebral aneurysm, carotid pseudoaneurysm from radiation injury, and blister aneurysms. We aimed to evaluate the effectiveness of utilizing the PED as a primary treatment for ruptured dissecting intracranial aneurysms. A single center retrospective review was conducted for all patients primarily treated with PED for acute subarachnoid hemorrhage (SAH) from ruptured dissecting cerebral aneurysms between December 2010 and February 2013. Patients were followed up with CT angiogram (CTA) or digital subtraction angiogram (DSA). Eight patients with a total of eight dissecting aneurysms were identified. The mean duration from SAH to treatment was 2.5 days. Six of the aneurysms arose from vertebral arteries and two from the basilar artery. Immediate check-DSA confirmed satisfactory contrast stasis in all eight cases, and complete aneurysmal obliteration was achieved at six months. There were two (25%) procedure-related complications, but no major procedure-related complications, such as thromboembolic events or rebleeding from aneurysm were encountered. The PED is a feasible treatment option for ruptured dissecting cerebral aneurysms in acute phase. According to our experience, using PED as flow-diverters in acute SAH does not significantly increase the complication risks or mortality rate if the antiplatelet regime is carefully monitored. Future studies shall evaluate the optimal antiplatelet regimen for using the PED in the acute phase.