Treatment of large proximal ureteral stones: extra corporeal shock wave lithotripsy versus semi-rigid ureteroscope with lithoclast

<p>Abstract</p> <p>Purpose</p> <p>Assessment of safety and efficacy of extracorporeal shockwave lithotripsy versus semi-rigid ureteroscope with lithoclast for treatment of large proximal ureteral stones.</p> <p>Materials and methods</p> <p>The study included 147 patients with large upper ureteral stones. SWL and ureteroscopy were performed in 71 and 76 patients respectively. Patients in the SWL group were treated with Siemens: - Modularis lithovario under intravenous sedation on an out patient basis. Patients in the ureteroscopy group were treated with (7.5 Fr) semi-rigid ureteroscope and lithoclast under spinal anesthesia on a day care basis.</p> <p>Results</p> <p>Stone - free rate for in situ SWL was 58% (41 of 71) patients. For semi-rigid ureteroscope accessibility of the stones was 94% (72 of 76) and the stone free rate was 92% (70 of 76) No major complications were encountered in both groups.</p> <p>Mean stone size was 1.34 ± 0.03 cm in the SWL group and 1.51 ± 0.04 in the ureteroscopy group.</p> <p>Conclusions</p> <p>Our study demonstrates that ureteroscopy with lithoclast can be considered as acceptable treatment modality for large proximal ureteral calculi and can be considered as fist line for treatment of large proximal ureteral stones.</p

Mechanocapillary Forming of Filamentary Materials.

The hierarchical structure and organization of filaments within natural materials determine their collective chemical and physical functionalities. Synthetic nanoscale filaments such as carbon nanotubes (CNTs) are known for their outstanding properties including high stiffness and strength at low density, and high electrical conductivity and current carrying capacity. Ordered assemblies of densely packed CNTs are therefore expected to enable the synthesis of new materials having outstanding multifunctional performance. However, current methods of CNT synthesis have inadequate control of quality, density and order. In pursuit of these needs, a new technique called capillary forming is used to manipulate vertically aligned (VA-) CNTs, and to enable their integration in applications ranging from microsystems to macroscale functional films. Capillary forming relies on shape-directed capillary rise during solvent condensation; followed by evaporation-induced shrinkage. Three-dimensional geometric transformations result from the heterogeneous strain distribution within the microstructures during the vapor-liquid-solid interface shrinkage. A portfolio of microscale CNT assemblies with highly ordered internal structure and freeform geometries including straight, bent, folded and helical profiles, are fabricated using this technique. The mechanical stiffness and electrical conductivity of capillary formed CNT micropillars are 5 GPa and 104 S/m respectively. These values are at least hundred-fold higher than as-grown CNT properties, and exceed the properties of typical microfabrication polymers. Responsive CNT-hydrogel composites are prototyped by combining isotropic moisture-induced swelling of the hydrogel with the anisotropic stiffness of CNTs to induce reversible self-directed shape changes of up to 30% stroke. Centimeter scale sheets are fabricated by mechanical rolling and capillary assisted joining of CNTs. The mechanical stiffness, strength and electrical conductivity of CNT sheets are comparable to those of continuous CNT microstructures; and can be tuned by engineering the morphology of the CNT joints. Finally, the applicability of mechanocapillary forming to other nanoscale filaments is demonstrated using silicon nanowires synthesized by metal assisted chemical etching. Further work using the methods developed in this dissertation could enable applications such as directional liquid transport, adhesives, and biosensors; toward an end goal of creating multifunctional surfaces having arbitrary structural, interfacial, and optical responsiveness.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91466/1/stawfick_1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/91466/2/stawfick_2.pd

Frequency Response and Eddy Current Power Loss in Magneto-Mechanical Transmitters

Magneto-mechanical transmitters offer a compact and low-power solution for the generation of ultra-low frequency (ULF) magnetic signals for through-ground and through-seawater communications. Resonant arrays of smaller magneto-mechanical transmitters are particularly interesting in this context as the physical scaling laws allow for the increase of operating frequency and reduce the power requirements for ULF signal generation. In this work, we introduce a generalized model for accurate prediction of frequency and mode shape in generalized magneto-mechanical resonator arrays (MMRAs) that accounts for near-field magnetic interactions as well as magnetically induced nonlinearity. Using experiments, we demonstrate that our predictive capability is significantly improved compared against simplified dipole approximations. We additionally model the eddy current losses internal to the array and find that they are in agreement with experimental observations.Comment: 12 pages, 8 figures, 6 table

Strain-engineered manufacturing of freeform carbon nanotube microstructures.

The skins of many plants and animals have intricate microscale surface features that give rise to properties such as directed water repellency and adhesion, camouflage, and resistance to fouling. However, engineered mimicry of these designs has been restrained by the limited capabilities of top-down fabrication processes. Here we demonstrate a new technique for scalable manufacturing of freeform microstructures via strain-engineered growth of aligned carbon nanotubes (CNTs). Offset patterning of the CNT growth catalyst is used to locally modulate the CNT growth rate. This causes the CNTs to collectively bend during growth, with exceptional uniformity over large areas. The final shape of the curved CNT microstructures can be designed via finite element modeling, and compound catalyst shapes produce microstructures with multidirectional curvature and unusual self-organized patterns. Conformal coating of the CNTs enables tuning of the mechanical properties independently from the microstructure geometry, representing a versatile principle for design and manufacturing of complex microstructured surfaces.This is the author accepted manuscript. The final published version can be found in Nature Communications here: http://www.nature.com/ncomms/2014/140729/ncomms5512/full/ncomms5512.html. This paper will be under embargo until 29/1/15

Topical Wound Oxygen Versus Conventional Compression Dressings in the Management of Refractory Venous Ulcers

Topical wound oxygen (TWO2) proposes an innovative therapy option in the management of refractory non-healing venous ulcers (RVU) that aims to accelerate wound healing. TWO2 accelerates epithelialisation. This leads to the development of a higher tensile strength collagen, which lessens scarring and the risk of recurrence. Sixty-seven limbs with 67 ulcers were managed using TWO2 therapy, and 65 limbs with 65 ulcers were managed using conventional compression dressings (CCD). The proportion of ulcers completely healed by 12 weeks was 76% in patients managed with TWO2, compared to 46% in patients managed with CCD (p < 0.0001). The mean reduction in ulcer surface area at 12 weeks was 96% in the TWO2 therapy group, compared to 61% in patients managed with CCD. The median time to full ulcer healing was 57 days in the TWO2 group, in contrast to 107 days in patients managed with CCD (p < 0.0001). TWO2 patients had a significantly improved Quality-Adjusted Time Spent Without Symptoms of disease and Toxicity of treatment (Q-TWiST) compared to CCD patients, denoting an improved outcome (p < 0.0001). TWO2 reduces the time needed for RVU healing and is successful in pain alleviation and MRSA elimination. TWO2 therapy radically degrades recurrence rates. Utilising diffused oxygen raises the capillary partial pressure of oxygen (Po2) levels at the wound site, stimulating epithelialisation, and granulation of new healthy tissue. Taking the social and individual aspects of chronic venous ulceration into account, the use of TWO2 can provide an overwhelmingly improved quality of life for long-time sufferers of this debilitating disease

Aorto-Uni-Iliac Stent Grafts with and without Crossover Femorofemoral Bypass for Treatment of Abdominal Aortic Aneurysms: A Parallel Observational Comparative Study

We investigated the safety and efficacy of primary aorto-uni-iliac (AUI) endovascular aortic repair (EVAR) without fem-fem crossover in patients with abdominal aortic aneurysm (AAA) and concomitant aortoiliac occlusive disease. 537 EVARs were implemented between 2002 and 2015 in University Hospital Galway, a tertiary referral center for aortic surgery and EVAR. We executed a parallel observational comparative study between 34 patients with AUI with femorofemoral crossover (group A) and six patients treated with AUI but without the crossover (group B). Group B patients presented with infrarenal AAAs with associated total occlusion of one iliac axis and high comorbidities. Technical success was 97% (n=33) in group A and 85% (n=5) in group B (P=0.31). Primary and assisted clinical success at 24 months were 88% (n=30) and 12% (n=4), respectively, in group A, and 85% (n=5) and 15% (n=1), respectively, in group B (P=0.125). Reintervention rate was 10% (n=3) in group A and 0% in group B (P=0.084). No incidence of postoperative critical lower limb ischemia or amputations occurred in the follow-up period. AUI without crossover bypass is a viable option in selected cases