Renal and visceral protection in thoracoabdominal aortic surgery

ObjectivesOpen thoracoabdominal aortic aneurysm (TAAA) repair traditionally carries substantial perioperative morbidity and mortality, primarily from distal aortic ischemia. Advances in surgical techniques, adjuncts, and strategies have greatly improved outcomes.MethodsWe analyzed outcomes of 1267 open consecutive TAAA repairs between January 2005 and September 2013. We provided cold crystalloid renal perfusion whenever the renal ostia were accessible; according to extent of repair, we selectively used left heart bypass and provided isothermic blood to the celiac axis and superior mesenteric artery. Repair was extensive (Crawford extent I and II) in 717 cases (57%). Left heart bypass was used in 645 (51%) cases, cold crystalloid renal perfusion in 987 (78%), and isothermic visceral perfusion in 318 (25%). Additional patient-specific surgical adjuncts included endarterectomy of renal or visceral vessels, open stent placement within these vessels, or use of both techniques; at least one was used in 447 repairs (35%).ResultsThirty-day survival was 95% (1198/1267); overall operative mortality was 8% (104/1267). Acute renal dysfunction occurred in 155 (12%), renal failure requiring hemodialysis at hospital discharge in 84 (7%), and bowel ischemia in 9 (<1%). Extent II and III TAAA repairs carried the highest risks of postoperative renal dysfunction and renal failure requiring hemodialysis at hospital discharge.ConclusionsContemporary protective strategies allow open TAAA repair with substantially fewer renal and visceral ischemic complications. Although bowel ischemia is uncommon, renal failure remains a concern, especially in extent II and extent III TAAA repairs. Additional studies are needed to identify and improve renal protection strategies

Inelastic neutron scattering in random binary alloys : an augmented space approach

Combining the augmented space representation for phonons with a generalized version of Yonezawa-Matsubara diagrammatic technique, we have set up a formalism to seperate the coherent and incoherent part of the total intensity of thermal neutron scattering from disordered alloys. This is done exacly without taking any recourse to mean-field like approximation (as done previously). The formalism includes disorder in masses, force constants and scattering lengths. Implementation of the formalism to realistic situations is performed by an augmented space Block recursion which calculates entire Green matrix and self energy matrix which in turn is needed to evaluate the coherent and incoherent intensities. we apply the formalism to NiPd and NiPt alloys. Numerical results on coherent and incoherent scattering cross sections are presented along the highest symmetry directions. Finally the incoherent intensities are compared with the CPA and also with experiments.Comment: 18 pages, 13 figure

Comparison of Efficiencies of Neurological Physical Examination, Neurothesiometer and PainDETECT Questionnaire in Diagnosing Diabetic Neuropathy

Objective:&nbsp;To compare the efficacies of neurological physical examination, neurothesiometer and PainDETECT questionnaire in diagnosing diabetic neuropathy. Study Design:&nbsp;Prospective cross-sectional Place and Duration of Study:&nbsp;Department of General Medicine, Nishtar Hospital Multan, Pakistan from 1st&nbsp;December 2018 to 10th&nbsp;March 2019. Materials and Methods:&nbsp;One hundred and four patients of both type 1 and type 2 diabetes visiting the outdoor department were included in this study. They were assessed by lab results of glycosylated hemoglobin, fasting and random blood sugar levels and neurological physical examination. Results: The physical examination with Michigan Neuropathy Screening instrument showed that around 29 of the patients were having established neuropathy. The PainDETECT questionnaire on the other hand showed about 42 patients having a definitive neuropathy while the neurothesiometer showed that 79 of the total patients had varying degrees of neuropathy. Conclusion:&nbsp;The neurothesiometer is a better diagnostic tool for diagnosing diabetic neuropathy in patients

Lattice thermal conductivity of disordered binary alloys : a formulation

We present here a formulation for the calculation of the configuration averaged lattice thermal conductivity in random alloys. Our formulation is based on the augmented-space theorem, introduced by one of us, combined with a generalized diagrammatic technique. The diagrammatic approach simplifies the problem of including effects of disorder corrections to a great extent. The approach allows us to obtain an expression for the effective heat current in case of disordered alloys, which in turn is used in a Kubo-Greenwood type formula for the thermal conductivity. We show that disorder scattering renormalizes the phonon propagators as well as the heat currents. The corrections to the current terms have been shown to be related to the self-energy of the propagators. We also study the effect of vertex corrections in a simplified ladder diagram approximation. A mode dependent diffusivity $D_{\gamma}$ and then a total thermal diffusivity averaged over different modes are defined. Schemes for implementing the said formalism are discussed. A few initial numerical results on the frequency and temperature dependence of lattice thermal conductivity are presented for NiPd alloy and are also compared with experiment. We also display numerical results on the frequency dependence of thermal diffusivity averaged over modes.Comment: 16 pages, 17 figure

Relating localized nanoparticle resonances to an associated antenna problem

We conceptually unify the description of resonances existing at metallic nanoparticles and optical nanowire antennas. To this end the nanoantenna is treated as a Fabry-Perot resonator with arbitrary semi-nanoparticles forming the terminations. We show that the frequencies of the quasi-static dipolar resonances of these nanoparticles coincide with the frequency where the phase of the complex reflection coefficient of the fundamental propagating plasmon polariton mode at the wire termination amounts to $\pi$. The lowest order Fabry-Perot resonance of the optical wire antenna occurs therefore even for a negligible wire length. This approach can be used either to easily calculate resonance frequencies for arbitrarily shaped nanoparticles or for tuning the resonance of nanoantennas by varying their termination.Comment: Submitted to Phys. Rev.

Vibrational properties of phonons in random binary alloys: An augmented space recursive technique in the k-representation

We present here an augmented space recursive technique in the k-representation which include diagonal, off-diagonal and the environmental disorder explicitly : an analytic, translationally invariant, multiple scattering theory for phonons in random binary alloys.We propose the augmented space recursion (ASR) as a computationally fast and accurate technique which will incorporate configuration fluctuations over a large local environment. We apply the formalism to $Ni_{55}Pd_{45}$, Ni_{88}Cr_12} and $Ni_{50}Pt_{50}$ alloys which is not a random choice. Numerical results on spectral functions, coherent structure factors, dispersion curves and disordered induced FWHM's are presented. Finally the results are compared with the recent itinerant coherent potential approximation (ICPA) and also with experiments.Comment: 20 pages, LaTeX, 23 figure