Enhanced heat capacity and a new temperature instability in superfluid He-4 in the presence of a constant heat flux near T-lambda

We present the first experimental evidence that the heat capacity of superfluid 4He, at temperatures very close to the lambda point Tλ, is enhanced by a constant heat flux Q. The heat capacity at constant Q, CQ, is predicted to diverge at a temperature Tc(Q)<Tλ at which superflow becomes unstable. In agreement with previous measurements, we find that dissipation enters our cell at a temperature, TDAS(Q), below the theoretical value, Tc(Q). We argue that TDAS(Q) can be accounted for by a temperature instability at the cell wall, and is therefore distinct from Tc(Q). The excess heat capacity we measure has the predicted scaling behavior as a function of T and Q, but it is much larger than predicted by current theory

Robotics in uro-oncologic surgery

In urology, the main use for the robotic technique has been in radical prostatectomy for prostate cancer. Robotic surgery for other organs, such as the kidneys and bladder, has been less explored. However, partial nephrectomy or radical nephroureterectomy can be difficult for inexperienced laparoscopic surgeons. The advent of the da Vinci robot, with multijointed endowristed instruments and stereoscopic vision, decreases the technical difficulty of intracorporeal suturing and improves the reconstructive steps. The objective of this article is to offer an overview of all robotic procedures recently developed in the field of urology. We evaluate the feasibility of these procedures and their potential advantages and disadvantages. We also describe perioperative, postoperative, and oncologic outcomes of robot-assisted surgery as well as perform a comparison with open and laparoscopic techniques. Comparative data and an adequate follow-up are needed to demonstrate equivalent oncologic outcomes in comparison with traditional open or laparoscopic procedures. Copyright

Laser fiber and flexible ureterorenoscopy: the safety distance concept

INTRODUCTION The costs of flexible ureterorenoscopes (fURS) and their repair oblige the surgeon to know the proper handling of instruments. There is a lack of evidence in the literature about the safety distance that the laser fiber should have once out from the scope to avoid instrumental damages. MATERIAL AND METHODS We performed an in-vitro observational study. Seven fURS were tested. The distance from the laser fiber tip and the fURS camera was measured at the first appearance on the endoscopic screen and when the fiber was reaching one fourth of the screen. Secondly, to evaluate the impact of the Holmium laser bubble according to the different fiber distances, an assessment of the size and shape of the bubble created at the tip of the fiber with the laser activated was done recording the images with an High Speed Camera. RESULTS The first appearance on the screen of the laser tip is different in different scopes. In all the scopes when observed that when the laser fiber was at \ubc of the screen the bubble was never touching the fURS tip. CONCLUSION Even if there is a big limitation of this study due the impossibility to measure and to evaluate the damage of the fURS tip surface, we observed that when the laser fiber tip reach \ubc of the screen, the bubble generated by the laser activation is never rebounding on the camera of the scope preserving it from laser damages. We can define this position as the "safety distance"

Cryotherapy for low risk prostate cancer, oncological and functional medium term outcomes : A three center prospective study

Objectives: Analyze the oncologic and functional outcomes in patients affected by low risk prostate cancer underwent prostate cryotherapy. Materiasl and methods: It's a prospective tricentric study of 434 patients treated with prostate cryoablation for low risk prostate cancer. By low risk we refer to the D'Amico's risk classification. Two cycles of freezing/thawing are run for each patient following the technique described by Onik. Results: For the 434 patients, the median age was 66 years with a standard deviation of \uc2\ub1 6.68, the average PSA was 6.17 ng/d/L, the median 5.55 with a standard deviation of \uc2\ub1 2.13, the mean prostate volume was 35.59 cc, the median 34.00 cc, with a standard deviation of \uc2\ub1 7.89. Biochemical failure occurred in 67 patients (15.4%). Pre-operative erectile function in men was distributed as follows: severe in 95 patients (19.2%), moderate in 95 (19.2%), medium-moderate in 180 (36.4%), mild in 92 (18.6%), with no dysfunction in 32 (6.5%) patients. Post-operative erectile function, measured 1 month after cryotherapy, was distributed as follows: severe in 321 (65%) patients, moderate in 69 (14%), medium-moderate in 79 (16%), mild in 23 (4.7%), and no dysfunction in only 2 patients (0.4%). Post-operative erectile function after 3 months was distributed as follows: severe in 233 (47.2%) patients, moderate in 66 (13.4%), medium-moderate in 122 (24.7%), mild in 65 (13.2%), and no dysfunction in 8 patients (1.6%). Urinary incontinence was present in 21 patients (4.8%) after 3 months while it dropped to 13 patients (2.9%) after 6 months. Conclusions: Cryotherapy in the treatment of prostate cancer remains a viable alternative. The availability of new cryoprobes and the use of new diagnostic means such as fusion magnetic resonance will make this more precise and more effective method

New Technologies in Endourology and Laser Lithotripsy: The Need for Evidence in Comprehensive Clinical Settings

Flexible ureteroscopy (fURS) with laser lithotripsy is currently the gold standard surgical treatment for ureteral and kidney stones with a maximum diameter of 2 cm [...]

Comparison among the available stone treatment techniques from the first European Association of Urology Section of Urolithiasis (EULIS) Survey: Do we have a queen?

Purpose The miniaturization of instruments has had an impact on stone management. The aims of this study were to highlight surgeon preferences among Retrograde Intra Renal Surgery (RIRS), Regular, Mini-, UltraMini- and Micro- Percutaneous Nephrolithotomy (PCNL) for urolithiasis and to compare the effectiveness and safety of these techniques in a real-life setting. Methods A 12-item survey regarding endourological techniques was conducted through Survey Monkey among attendees of the 2013 European Association of Urology Section of Urolithiasis meeting. We asked responders to share data from the last 5 cases they performed for each technique. Procedures were stratified according to stone size and the centres\u2019 surgical volume. Techniques were compared in terms of effectiveness and safety. Analyses were performed on the overall group and a subgroup of 1\u20132 cm stones. Results We collected data from a total of 420 procedures by 30, out of 78, urologists who received the survey (response rate 38%): 140 RIRS, 141 Regular-PCNL (>20 Ch), 67 Mini-PCNL (14\u201320 Ch), 28 UltraMini-PCNL (11\u201313 Ch) and 44 Micro-PCNL (4,8\u20138 Ch). Techniques choice was influenced by stone size and the centre\u2019s surgical volume. Effectiveness and safety outcomes were influenced by stone size, independently of the technique. The stone-free rate was significantly lower in Micro-PCNL compared to Regular-PCNL. This was not confirmed for 1\u20132 cm stones. All techniques presented a lower complication rate than Regular-PCNL, with Mini-PCNL being the most protective technique compared to Regular-PCNL. Conclusions Stone size seems to drive treatment choice. Miniaturized PCNL techniques are widely employed for 1\u20132 cm stones, in particular in higher surgical volume centres. Mini-PCNL and RIRS are growing in popularity for stones > 2 cm. Mini-PCNL seems to be a good compromise, being the most effective and safe procedure among PCNL techniques. RIRS is characterized by satisfactory stone-free and low complication rates

Variations in the mineral content of bottled 'carbonated or sparkling' water across Europe : a comparison of 126 brands across 10 countries

Kidney stone disease is a common disease with high recurrence rates. Sufficient intake of water is the cornerstone in primary prevention of stone disease. However, the mineral composition of water can affect urinary minerals and influence stone formation. The aim of this study is to assess the variation in the mineral composition of bottled sparkling or carbonated drinking water across Europe. The two largest supermarket chains in each participating country were visited to obtain data on mineral composition regarding bicarbonate, calcium, magnesium, potassium, sodium and sulphates of sparkling or carbonated waters by reading the ingredient labels on the bottles supplied by the manufacturers. Alternatively, the web-shops of these supermarkets were consulted. In total, 126 sparkling water brands across ten European countries were analysed regarding mineral composition. The median concentrations per mineral varied greatly. The greatest variation in median mineral content was found for sodium and sulphates with levels ranging from 3.1 mg/l to 63.0 mg/l and 6.0 mg/l to 263.0 mg/l respectively. A wide distribution of calcium content was found in Switzerland, with calcium levels reaching up to 581.6 mg/l. This study confirms that the mineral composition of sparkling or carbonated water varies greatly across Europe. Patients with kidney stone disease should be aware that the mineral content of water may influence stone formation and be mindful of the great variation that exists between different water brands. Mineral water can be a source of potential promotors or inhibitors of stone formation and patients and urologists need to be mindful of this