Advances and Prospects of High-Voltage Spinel Cathodes for Lithium-Based Batteries
Abstract not provided.
Chemistry↗
SEARCH · Engineering Papers
Results for “insertion”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Automatic inspection of program state in an uncooperative environment
Abstract The program state is formed by the values that the program manipulates. These values are stored in the stack, in the heap, or in static memory. The ability to inspect the program state is useful as a debugging or as a verification aid. Yet, there exists no general technique to insert inspection points in type‐unsafe languages such as C or C++. The difficulty comes from the need to traverse the memory graph in a so‐called uncooperative environment. In this article, we propose an automatic technique to deal with this problem. We introduce a static code transformation approach that inserts in a program the instrumentation necessary to report its internal state. Our technique has been implemented in LLVM. It is possible to adjust the granularity of inspection points trading precision for performance. In this article, we demonstrate how to use inspection points to debug compiler optimizations; to augment benchmarks with verification code; and to visualize data structures.
Magalhães, José Wesley de Souza↗
Low-energy effective field theory below the electroweak scale: anomalous dimensions
We compute the one-loop anomalous dimensions of the low-energy effective Lagrangian below the electroweak scale, up to terms of dimension six. The theory has 70 dimension-five and 3631 dimension-six Hermitian operators that preserve baryon and lepton number, as well as additional operators that violate baryon number and lepton number. The renormalization group equations for the quark and lepton masses and the QCD and QED gauge couplings are modified by dimension-five and dimension-six operator contributions. We compute the renormalization group equations from one insertion of dimension-five and dimension-six operators, as well as two insertions of dimension-five operators, to all terms of dimension less than or equal to six. As a result, the use of the equations of motion to eliminate operators can be ambiguous, and we show how to resolve this ambiguity by a careful use of field redefinitions.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Coulomb branch operators and mirror symmetry in three dimensions
We develop new techniques for computing exact correlation functions of a class of local operators, including certain monopole operators, in three-dimensional N = 4 abelian gauge theories that have superconformal infrared limits. These operators are position-dependent linear combinations of Coulomb branch operators. They form a one-dimensional topological sector that encodes a deformation quantization of the Coulomb branch chiral ring, and their correlation functions completely fix the (n ≤ 3)-point functions of all half-BPS Coulomb branch operators. Using these results, we provide new derivations of the conformal dimension of half-BPS monopole operators as well as new and detailed tests of mirror symmetry. Our main approach involves supersymmetric localization on a hemisphere HS 3 with half-BPS boundary conditions, where operator insertions within the hemisphere are represented by certain shift operators acting on the HS 3 wavefunction. By gluing a pair of such wavefunctions, we obtain correlators on S 3 with an arbitrary number of operator insertions. Lastly, we show that our results can be recovered by dimensionally reducing the Schur index of 4D N=2 theories decorated by BPS ’t Hooft-Wilson loops.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Exact correlators on the Wilson loop in $$ \mathcal{N}=4 $$ SYM: localization, defect CFT, and integrability
We compute a set of correlation functions of operator insertions on the 1/8 BPS Wilson loop in N=4 SYM by employing supersymmetric localization, OPE and the Gram-Schmidt orthogonalization. These correlators exhibit a simple determinant structure, are position-independent and form a topological subsector, but depend nontrivially on the ’t Hooft coupling and the rank of the gauge group. When applied to the 1/2 BPS circular (or straight) Wilson loop, our results provide an infinite family of exact defect CFT data, including the structure constants of protected defect primaries of arbitrary length inserted on the loop. At strong coupling, we show precise agreement with a direct calculation using perturbation theory around the AdS 2 string worldsheet. We also explain the connection of our results to the “generalized Bremsstrahlung functions” previously computed from integrability techniques, reproducing the known results in the planar limit as well as obtaining their finite N generalization. Furthermore, we show that the correlators at large N can be recast as simple integrals of products of polynomials (known as Q-functions) that appear in the Quantum Spectral Curve approach. This suggests an interesting interplay between localization, defect CFT and integrability.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Twistorial monopoles & chiral algebras
We initiate the study of how the insertion of magnetically charged states in 4d self-dual gauge theories impacts the 2d chiral algebras supported on the celestial sphere at asymptotic null infinity, from the point of view of the 4d/2d twistorial correspondence introduced by Costello and the second author. By reducing the 6d twistorial theory to a 3d holomorphic-topological theory with suitable boundary conditions, we can motivate certain non-perturbative enhancements of the celestial chiral algebra corresponding to extensions by modules arising from 3d boundary monopole operators. We also identify the insertion of 4d (non-abelian) monopoles with families of spectral flow automorphisms of the celestial chiral algebra.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Null states and time evolution in a toy model of black hole dynamics
Abstract Spacetime wormholes can provide non-perturbative contributions to the gravitational path integral that make the actual number of statese S in a gravitational system much smaller than the number of states$$ {e}^{S_{\textrm{p}}} $$ e S p predicted by perturbative semiclassical effective field theory. The effects on the physics of the system are naturally profound in contexts in which the perturbative description actively involvesN=O(e S ) of the possible$$ {e}^{S_{\textrm{p}}} $$ e S p perturbative states; e.g., in late stages of black hole evaporation. Such contexts are typically associated with the existence of non-trivial quantum extremal surfaces. However, by forcing a simple topological gravity model to evolve in time, we find that such effects can also have large impact forN≪e S (in which case no quantum extremal surfaces can arise). In particular, even for smallN, the insertion of generic operators into the path integral can cause the non-perturbative time evolution to differ dramatically from perturbative expectations. On the other hand, this discrepancy is small for the special case where the inserted operators are non-trivial only in a subspace of dimensionD≪e S . We thus study this latter case in detail. We also discuss potential implications for more realistic gravitational systems.
Physics↗
2D Kac-Moody symmetry of 4D Yang-Mills theory
Scattering amplitudes of any four-dimensional theory with nonabelian gauge group G may be recast as two-dimensional correlation functions on the asymptotic twosphere at null in nity. The soft gluon theorem is shown, for massless theories at the semiclassical level, to be the Ward identity of a holomorphic two-dimensional G-Kac-Moody symmetry acting on these correlation functions. Holomorphic Kac-Moody current insertions are positive helicity soft gluon insertions. Furthermore, the Kac-Moody transformations are a CPT invariant subgroup of gauge transformations which act nontrivially at null in nity and comprise the four-dimensional asymptotic symmetry group.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Superluminal chaos after a quantum quench
Thermal states holographically dual to black holes in Einstein gravity display maximal Lyapunov growth as well as “butterfly effect cones”. We study these effects in highly non-equilibrium states, obtained from an initial thermal state by the sudden injection of energy. We do this by computing out-of-time-order correlators (OTOCs) in BTZ-Vaidya spacetimes, which describe transitions between black holes at different temperatures. If both pairs of boundary operators appearing in the OTOC are inserted before the energy injection, we recover standard results, with butterfly effect cones displaying a light-cone structure. But when one pair of operators is inserted before and the other pair after the energy injection, the Lyapunov growth saturates the chaos bounds set by the local temperatures and the butterfly effect cones can “open up”, becoming superluminal, albeit in a way that does not violate causality. In the limiting case, in which the initial state is the vacuum, Lyapunov growth only starts after the energy injection. Our computations of the OTOCs are phrased in terms of gravitationally interacting particles, where fields are treated in a geodesic approximation and the eikonal phase shift is expressed in terms of stress tensors and shock waves associated to geodesics.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Decreasing transmembrane segment length greatly decreases perfringolysin O pore size
Perfringolysin O (PFO) is a transmembrane (TM) β-barrel protein that inserts into mammalian cell membranes. Once inserted into membranes, PFO assembles into pore-forming oligomers containing 30–50 PFO monomers. These form a pore of up to 300 Å, far exceeding the size of most other proteinaceous pores. In this study, we found that altering PFO TM segment length can alter the size of PFO pores. A PFO mutant with lengthened TM segments oligomerized to a similar extent as wild-type PFO, and exhibited pore-forming activity and a pore size very similar to wild-type PFO as measured by electron microscopy and a leakage assay. In contrast, PFO with shortened TM segments exhibited a large reduction in pore-forming activity and pore size. This suggests that the interaction between TM segments can greatly affect the size of pores formed by TM β-barrel proteins. PFO may be a promising candidate for engineering pore size for various applications.
59 BASIC BIOLOGICAL SCIENCES↗
Venous Access Ports: Indications, Implantation Technique, Follow-Up, and Complications
The subcutaneous venous access device (SVAD or 'port') is a critical component in the care of patients with chronic disease. The modern SVAD provides reliable access for blood withdrawal and medication administration with minimal disruption to a patient's lifestyle. Because of improved materials and catheter technology, today's ports are lighter and stronger and capable of high-pressure injections of contrast for cross-sectional imaging. The majority of SVAD placement occurs in interventional radiology departments due to their ability to provide this service at lower costs, lower, complication rates, and greater volumes. Port-insertion techniques vary depending on the operator, but all consist of catheter placement in the central venous circulation followed by subcutaneous pocket creation and port attachment to the catheter with fixation and closure of the pocket. Venous access challenges occasionally occur in patients with central vein occlusions, necessitating catheterization of collateral veins or port placement in alternate locations. Complications of SVADs include those associated with the procedure as well as short- (<30 days) and long-term problems. Procedural and early complications are quite rare due to the near-universal use of real-time ultrasound guidance for vein puncture, but they can include hematoma, catheter malposition, arrhythmias, and pneumothorax. Late problems include both thrombotic complications (native venous or port-catheter thrombosis) and infections (tunnel or pocket infections or catheter-associated bloodstream infections). Most guidelines suggest that 0.3 infections/1000 catheter days is an appropriate upper threshold for the insertion of SVADs.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
The Optional VenaTech{sup Trade-Mark-Sign} Convertible{sup Trade-Mark-Sign} Vena Cava Filter: Experimental Study in Sheep
Purpose: Retrieval of optional caval filters may be impaired by filter tilting, migration, fracture, or embedding in the IVC wall. The goal of this experimental study was to evaluate a new optional filter, convertible by unlocking and removing the filter head. Methods: Forty-nine Pre-Alp sheep (average weight, 55 kg) were anesthetized. IVC was catheterized via the right femoral vein (n = 46) or via the internal jugular vein (n = 3) with a 12.9-F sheath. VenaTech{sup Trade-Mark-Sign} Convertible{sup Trade-Mark-Sign} IVC filters were inserted as either permanent filters (n = 14) or as filters to be converted. Conversion was immediately after deployment (n = 19) or delayed after 1, 3, or 6 months (n = 20). Filter delivery, deployment, and conversion with measurement of migration and tilting were evaluated by cavography. Incorporation of the filter's stabilizers and arms in the IVC wall was assessed by gross anatomy. Results: Delivery system insertion, filter release, and immediate conversion were successful in all cases. Delayed conversion was completed in all but one sheep, due to insufficient snare tension. Complimentary balloon-catheter inflation was required in 12 of 20 delayed conversions to achieve filter opening. In all 49 sheep, no thrombosis, migration, or significant tilting occurred. Within 4 weeks of conversion, the filter's stabilizers and arms were incorporated into the IVC wall. Upon removal, the filter head was free of intimal growth. Conclusions: The VenaTech{sup Trade-Mark-Sign} Convertible{sup Trade-Mark-Sign} optional IVC filter was successfully implanted in all sheep with no migration or tilting. Conversion at various dates by filter head removal was feasible in all but one case.
60 APPLIED LIFE SCIENCES↗
Phlegmasia Caerulea Dolens in a Patient With an Inferior Vena Cava Filter: Treatment of Massive Iliocaval Thrombosis Using Local Intravenous Catheter-Directed Thrombolysis
Phlegmasia caerulea dolens (PCD) is a potentially disastrous complication of inferior vena cava filter insertion, and its optimum management has not been clearly established. We present a case report of a patient with pulmonary embolism and acute adrenal haemorrhage who developed PCD secondary to massive iliocaval thrombosis after insertion of a Cook Celect removable filter. Local intravenous catheter-directed thrombolysis (CDT), followed by systemic anticoagulation, achieved limb salvage and virtual resolution of symptoms at 3 months without complications. CDT can be a successful primary treatment of filter-associated PCD and can be safe in selected patients with acute nontraumatic haemorrhage. Systemic anticoagulation may subsequently restore complete venous patency and may therefore be a useful approach to postthrombolysis management of residual iliocaval thrombus when filter removal is indicated.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Percutaneous Extraction of Cement Leakage After Vertebroplasty Under CT and Fluoroscopy Guidance: A New Technique
Purpose: We report a new minimally invasive technique of extraction of cement leakage following percutaneous vertebroplasty in adults. Methods: Seven adult patients (five women, two men; mean age: 81 years) treated for vertebral compression fractures by percutaneous vertebroplasty had cement leakage into perivertebral soft tissues along the needle route. Immediately after vertebroplasty, the procedure of extraction was performed under computed tomography (CT) and fluoroscopy guidance: a Chiba needle was first inserted using the same route as the vertebroplasty until contact was obtained with the cement fragment. This needle was then used as a guide for an 11-gauge Trocar t'am (Thiebaud, France). After needle withdrawal, a 13-gauge endoscopy clamp was inserted through the cannula to extract the cement fragments. The whole procedure was performed under local anesthesia. Results: In each patient, all cement fragments were withdrawn within 10 min, without complication. Conclusions: This report suggests that this CT- and fluoroscopy-guided percutaneous technique of extraction could reduce the rate of cement leakage-related complications.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Cephalic Arch Stenosis in Autogenous Haemodialysis Fistulas: Treatment With the Viabahn Stent-Graft
Cephalic arch stenosis (CAS) is an important and common cause of dysfunction in autogenous haemodialysis fistulas that requires multiple reinterventions and aggressive surveillance. We evaluated the safety and efficacy of the Viabahn stent-graft for the management of CAS. Between April 2005 and October 2011, 11 consecutive patients [four men and seven women (mean age 56.7 years)] with CAS and dysfunctional fistulas were treated with insertion of 11 Viabahn stent-grafts. Six stent-grafts were inserted due to residual stenosis after angioplasty and five for fistuloplasty-induced rupture. No patient was lost to follow-up. The technical and clinical success rate was 100 %. Primary access patency rates were 81.8 % [95 % confidence interval (CI) 0.482-0.977] at 6 months and 72.7 % (95 % CI 0.390-0.939) at 12 months. Secondary access patency rates were 90.9 % at 6 months (95 % CI 0.587-0.997). There were no procedure-related complications. Mean follow-up was 543.8 days (range 156-2,282). The use of the Viabahn stent-graft in the management of CAS is technically feasible and, in this small series, showed patency rates that compare favorably with historical data of angioplasty and bare stents.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Percutaneous Intraductal Radiofrequency Ablation is a Safe Treatment for Malignant Biliary Obstruction: Feasibility and Early Results
Purpose. Previous clinical studies have shown the safety and efficacy of this novel radiofrequency ablation catheter when used for endoscopic palliative procedures. We report a retrospective study with the results of first in man percutaneous intraductal radiofrequency ablation in patients with malignant biliary obstruction. Methods. Thirty-nine patients with inoperable malignant biliary obstruction were included. These patients underwent intraductal biliary radiofrequency ablation of their malignant biliary strictures following external biliary decompression with an internal-external biliary drainage. Following ablation, they had a metal stent inserted. Results. Following this intervention, there were no 30-day mortality, hemorrhage, bile duct perforation, bile leak, or pancreatitis. Of the 39 patients, 28 are alive and 10 patients are dead with a median survival of 89.5 (range 14-260) days and median stent patency of 84.5 (range 14-260) days. One patient was lost to follow-up. All but one patient had their stent patent at the time of last follow-up or death. One patient with stent blockage at 42 days postprocedure underwent percutaneous transhepatic drain insertion and restenting. Among the patients who are alive (n = 28) the median stent patency was 92 (range 14-260) days, whereas the patients who died (n = 10) had a median stent patency of 62.5 (range 38-210) days. Conclusions. In this group of patients, it appears that this new approach is feasible and safe. Efficacy remains to be proven in future, randomized, prospective studies.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Embolization by Direct Puncture with a Transpedicular Approach Using an Isocenter Puncture (ISOP) Method in a Patient with a Type II Endoleak After Endovascular Aortic Repair (EVAR)
BackgroundEndovascular aortic repair (EVAR) requires further intervention in 20-30 % of cases, often due to type II endoleak (T2EL). Management options for T2EL include transarterial embolization, direct puncture (DP), or transcaval embolization. We report the case of an 80-year-old man with T2EL who successfully underwent DP embolization.MethodsEmbolization by DP was performed with a transpedicular approach using an isocenter puncture (ISOP) method. An isocenter marker (ICM) was placed at a site corresponding to the aneurysm sac on fluoroscopy in two directions (frontal and lateral views). A vertebroplasty needle was inserted tangentially to the ICM under fluoroscopy and advanced to the anterior wall of the vertebral body. A 20 cm-length, 20-G-PTCD needle was inserted through the outer needle of the 13-G needle and advanced to the ICM. Sac embolization using 25 % N-buty-2-cyanoacrylate diluted with Lipiodol was performed. After complete embolization, rotational DA confirmed good filling of the sac with Lipiodol. The outer cannula and 13-G needle were removed and the procedure was completed.ResultsThe patient was discharged the next day. Contrast-enhanced computed tomography 1 and 8 months later showed no Lipiodol washout in the aneurysm sac, no endoleak recurrence, and no expansion of the excluded aneurysm.ConclusionDP with a transpedicular approach using ISOP may be useful when translumbar and transabdominal approaches prove difficult.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Single Center Experience with the AngioVac Aspiration System
PurposeThe AngioVac catheter system is a mechanical suction device designed for removal of intravascular material using extracorporeal veno-venous bypass circuit. The purpose of this study is to present the outcomes in patients treated with the AngioVac aspiration system and to discuss its efficacy in different vascular beds.Materials and MethodsA retrospectively review was performed of seven patients treated with AngioVac between October 2013 and December 2014. In 6/7 cases, the AngioVac cannula was inserted percutaneously and the patient was placed on veno-venous bypass. In one of the cases, the cannula was inserted directly into the Fontan circuit after sternotomy and the patient was maintained on cardiopulmonary bypass. Thrombus location included iliocaval (2), SVC (1), pulmonary arteries (1), Fontan circuit and Glenn shunt with pulmonary artery extension (1), right atrium (1), and IVC with renal vein extension (1).ResultsThe majority of thrombus (50–95 %) was removed in 5/7 cases, and partial thrombus removal (<50 %) was confirmed in 2/7 cases. Mean follow-up was 205 days (range 64–403 days). All patients were alive at latest follow-up. Minor complications included three neck hematomas in two total patients. No major complications occurred.ConclusionAngioVac is a useful tool for acute thrombus removal in the large vessels. The setup and substantial cost may limit its application in straightforward cases. More studies are needed to establish the utility of AngioVac in treatment of intravascular and intracardiac material.
62 RADIOLOGY AND NUCLEAR MEDICINE↗