Stone Mass Research Articles

Evaluating the efficacy of bimanual compression of abdomen-flank to control postoperative bleeding after percutaneous nephrolithotomy: A randomized clinical trial.

To investigate the influence of bimanual compression of abdomen-flank to control bleeding after completion of percutaneous nephrolithotomy (PCNL) including tubeless PCNL. This study is a parallel-group randomized clinical trial with 1:1:1 randomization. Ninety patients who were candidates for PCNL during July to October 2019 were enrolled. After completion of PCNL operation, patients were randomized into three groups to receive bimanual abdomen-flank compression for 0, 3, and 7 min by the operating surgeon with the opening of sealed envelopes (groups 0, 3, and 7 min afterwards). Preoperative, 24, and 48 h postoperative hemoglobin (Hb) and electrolytes were collected. The primary endpoint of interest was the comparison of 48-h blood loss across study groups. Secondary endpoints included the percent drop in 24- and 48-h Hb, transfusion rates, and operation complications. This trial is registered at www.irct.ir with the following number: IRCT20190618043925N1 on 18 July 2019. There was no statistically significant difference in study groups regarding stone mass, stone location, access location, and patients' age (all p > 0.05). The medians (IQR) of 48-h blood loss were 490 mL (105-916), 338 mL (160-933), and 413 mL (71-650) in groups of 0, 3, and 7 min. The percent drop in 24-h postoperative Hb relative to preoperative Hb were 11.5 ± 8.6% versus 9.2 ± 7.3% versus 9.3 ± 6.8% (p = 0.44) and relative values for the percent drop in 48-h Hb relative to preoperative Hb were 8.6 ± 8.7% versus 9.5 ± 9.9% versus 7.2 ± 9.6% (p = 0.63) in groups of 0, 3, and 7 min respectively. Transfusion was needed in four patients in group 0 min, five patients in group 3 min, and three patients in group 7 min. The results of this study reveal that postoperative bimanual compression of abdomen-flank has no statistically significant influence on the control of bleeding after PCNL operations.

Ex Vivo Renal Stone Dusting: Impact of Laser Modality, Ureteral Access Sheath, and Suction on Total Stone Clearance.

Introduction and Objectives: Conventional renal stone dusting is challenging; the holmium (Ho:YAG) laser and holmium with MOSES effect (Ho:YAG-MOSES) fail to uniformly produce fragments ≤100 μm (i.e., dust). The superpulse thulium fiber laser (sTFL) may more effectively render uroliths into "dust," and may thus improve stone-free rates. Accordingly, we performed ex vivo evaluations with all three laser modalities, assessing stone fragments and stone clearance. Methods: Seventy-two ex vivo porcine kidney-ureter models were divided into 12 groups of 6: laser type (Ho:YAG, Ho:YAG-MOSES, sTFL), ureteroscope with and without applied suction, and the presence or absence of a 14F ureteral access sheath (UAS). Calcium oxalate stones were preweighed and implanted into each kidney via a pyelotomy. Stones were treated at 16W using dusting settings of 0.4J × 40Hz (Ho:YAG), 0.2J × 80Hz (Ho:YAG-MOSES), and 0.2J × 80Hz (sTFL) for up to 20 minutes. No stone basketing was performed. Kidneys were bivalved and residual fragments were collected, dried, weighed, and sieved to determine fragment size and stone clearance. Results: Initial stone mass (mg), procedure time (seconds), and laser energy expenditure (kJ) were similar in all 12 groups. The greatest stone clearance was seen with sTFL + suction + UAS (94%) compared with a conventional technique (Ho:YAG + no suction + no UAS) (65%, p < 0.01). The use of sTFL provided greater stone clearance than Ho:YAG or Ho:YAG-MOSES. Aspiration improved stone clearance for sTFL (p = 0.01), but not for Ho:YAG or Ho:YAG-MOSES, consistent with the creation of smaller fragments with sTFL. Presence of a 14F UAS improved stone clearance in all scenarios (p < 0.01). Conclusions: In this ex vivo study, stone clearance was optimized under the following conditions: sTFL, 14F UAS, and aspiration. This combination resulted in 94% of stone fragments being cleared; the 6% remaining fragments were all <2 mm. In all scenarios, deployment of a 14F UAS improved stone clearance.

Impact of Pulse Mode on Dusting Effect for Holmium Laser Lithotripsy: In Vitro Evaluation With Calcium Oxalate Monohydrate Stones

ObjectiveTo assess the distribution of stone fragments (<0.25->2 mm) after in vitro dusting laser lithotripsy with varying pulse modes using canine calcium oxalate monohydrate (COM) stones. Recent work demonstrates that fragments <0.25 mm are ideal for dusting, and we hypothesized advanced pulse modes might improve this outcome. MethodsA 3D-printed bulb was used as a calyceal model containing a single COM stone. A 230-core fiber (Lumenis) was passed through a ureteroscope (LithoVue, Boston Scientific). Contact laser lithotripsy by a single operator was performed with dusting settings (0.5J x 30Hz; Moses Pulse120H) to deliver 1kJ of energy for each trial. Short pulse (SP), long pulse (LP), Moses Distance (MD) and Moses Contact (MC) modes were tested with 5 trials for each parameter. Primary outcome was mass of fragments <0.25, <0.5, <1, and <2 mm. Laser fiber tip degradation was measured using a digital caliper. ResultsMass of stone fragments <0.25 mm varied from 34.6%-43.0% depending on the pulse mode, with no statistically significant differences between modes. MC (98.5%) produced a greater mass of fragments <2 mm compared to LP (86.1%; P = .046) but not SP (92.0%). Significantly less fiber tip burnback occurred with MC (0.29 mm) and MD (0.28 mm), compared to SP (0.83 mm; P < .0005). ConclusionRegardless of pulse mode, greater than one-third of the mass of COM stone was reduced to fragments <0.25 mm following contact laser lithotripsy. MC produced a greater mass of fragments <2 mm compared to LP and demonstrated less fiber tip burnback compared to SP.

A burst wave lithotripsy system for urinary stones in pet cats

Upper urinary tract stones are becoming more prevalent in cats. Surgery to address obstructing stones has poor outcomes and such stones can rarely be treated with medical therapy. Burst wave lithotripsy (BWL) is a non-invasive, ultrasound-guided, handheld focused ultrasound technology to disintegrate urinary stones, which is now in human clinical trials. In this project, we created a scaled version of the system for use on pet cats, adjusting geometric parameters and frequency of the transducer to account for differences in anatomic scale and stone size. A 650-kHz prototype transducer was fabricated, calibrated, and tested on 25 natural feline stones 2–5 mm applying 20-cycle pulses at 10 Hz pulse repetition rate with three different focal pressure amplitudes ≤8.9 MPa in an in vitro tissue phantom. The fragments were sieved in 10-min intervals to assess breakage. The results demonstrated that between 73%–96% of the stone mass was reduced to fragments i&lt;1 mm in a 30-min exposure, with only 2/25 stones showing no visible fragmentation. These data suggest BWL can fragment feline ureteral stones and that a high-frequency system can produce small fragments more likely to pass through the small ureter of a cat. [Work supported by NIDDK P01 DK043881.]

The biomechanical characteristics of the strongman atlas stone lift.

BackgroundThe atlas stone lift is a popular strongman exercise where athletes are required to pick up a large, spherical, concrete stone and pass it over a bar or place it on to a ledge. The aim of this study was to use ecologically realistic training loads and set formats to (1) establish the preliminary biomechanical characteristics of athletes performing the atlas stone lift; (2) identify any biomechanical differences between male and female athletes performing the atlas stone lift; and (3) determine temporal and kinematic differences between repetitions of a set of atlas stones of incremental mass.MethodsKinematic measures of hip, knee and ankle joint angle, and temporal measures of phase and repetition duration were collected whilst 20 experienced strongman athletes (female: n = 8, male: n = 12) performed three sets of four stone lifts of incremental mass (up to 85% one repetition maximum) over a fixed-height bar.ResultsThe atlas stone lift was categorised in to five phases: the recovery, initial grip, first pull, lap and second pull phase. The atlas stone lift could be biomechanically characterised by maximal hip and moderate knee flexion and ankle dorsiflexion at the beginning of the first pull; moderate hip and knee flexion and moderate ankle plantarflexion at the beginning of the lap phase; moderate hip and maximal knee flexion and ankle dorsiflexion at the beginning of the second pull phase; and maximal hip, knee extension and ankle plantarflexion at lift completion. When compared with male athletes, female athletes most notably exhibited: greater hip flexion at the beginning of the first pull, lap and second pull phase and at lift completion; and a shorter second pull phase duration. Independent of sex, first pull and lap phase hip and ankle range of motion (ROM) were generally smaller in repetition one than the final three repetitions, while phase and total repetition duration increased throughout the set. Two-way interactions between sex and repetition were identified. Male athletes displayed smaller hip ROM during the second pull phase of the first three repetitions when compared with the final repetition and smaller hip extension at lift completion during the first two repetitions when compared with the final two repetitions. Female athletes did not display these between-repetition differences.ConclusionsSome of the between-sex biomechanical differences observed were suggested to be the result of between-sex anthropometric differences. Between-repetition differences observed may be attributed to the increase in stone mass and acute fatigue. The biomechanical characteristics of the atlas stone lift shared similarities with the previously researched Romanian deadlift and front squat. Strongman athletes, coaches and strength and conditioning coaches are recommended to take advantage of these similarities to achieve greater training adaptations and thus performance in the atlas stone lift and its similar movements.

MP65-05 SUPERPULSE THULIUM, HOLMIUM, AND HOLMIUM MOSES LASER LITHOTRIPSY: AN EX-VIVO LABORATORY EVALUATION ON THE EFFECTIVENESS OF “DUSTING” COUPLED WITH URETEROSCOPIC FRAGMENT ASPIRATION

You have accessJournal of UrologyStone Disease: Surgical Therapy V (MP65)1 Sep 2021MP65-05 SUPERPULSE THULIUM, HOLMIUM, AND HOLMIUM MOSES LASER LITHOTRIPSY: AN EX-VIVO LABORATORY EVALUATION ON THE EFFECTIVENESS OF “DUSTING” COUPLED WITH URETEROSCOPIC FRAGMENT ASPIRATION Pengbo Jiang, Akhil Peta, Raphael Arada, Maged Ayad, Andrew Afyouni, Luke Limfuenco, Andrew Brevik, Nicholas Nguyen, Zhamshid Okhunov, Roshan Patel, Jaime Landman, and Ralph Clayman Pengbo JiangPengbo Jiang More articles by this author , Akhil PetaAkhil Peta More articles by this author , Raphael AradaRaphael Arada More articles by this author , Maged AyadMaged Ayad More articles by this author , Andrew AfyouniAndrew Afyouni More articles by this author , Luke LimfuencoLuke Limfuenco More articles by this author , Andrew BrevikAndrew Brevik More articles by this author , Nicholas NguyenNicholas Nguyen More articles by this author , Zhamshid OkhunovZhamshid Okhunov More articles by this author , Roshan PatelRoshan Patel More articles by this author , Jaime LandmanJaime Landman More articles by this author , and Ralph ClaymanRalph Clayman More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002105.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Conventional renal stone dusting is challenging, as both the holmium laser (Ho:YAG) and holmium with MOSES technology (MOSES) fail to reliably reduce calculi to fragments <100 microns (i.e. dust). The Superpulse thulium fiber laser (sTFL) is an emerging technology that may allow for more effective “dusting” of uroliths. We evaluated each of the three laser options using “dusting” settings and then evaluated the effectiveness of fragment aspiration via a dual lumen ureteroscope. METHODS: Seventy-two ex-vivo porcine kidney-ureter models were divided into 12 groups: laser type (Ho:YAG, MOSES, sTFL), ureteroscope (URS) with a single or dual lumen, and use of a 14Fr ureteral access sheath (UAS) or no sheath. Calcium oxalate stones were pre-weighed and implanted into each kidney via a pyelotomy. Stones were treated at 16 watts using dusting settings of 0.4Jx40Hz (Ho:YAG and MOSES), and 0.2Jx80Hz (sTFL) for a maximum period of 20 minutes. No stone basketing was performed; however, aspiration via the dual lumen ureteroscope was performed. The kidneys were bi-valved and residual fragments were collected, dried, weighed, and then sieved to determine what proportion of the remnants were larger than dust (i.e. >100 microns). RESULTS: Initial stone mass (mg), procedure time (sec), and laser energy expenditure (kJ) were similar amongst groups. The greatest stone clearance was seen with sTFL+dual URS+UAS (94%) compared to conventional technique (Ho:YAG+single+no UAS) at 65% (p<0.01). The use of sTFL resulted in significantly greater stone clearance than either Ho:YAG or Ho:YAG-MOSES. Aspiration via the dual lumen URS significantly improved stone clearance for sTFL (p=0.01) but not for Ho:YAG or Ho:YAG-MOSES. The use of a 14F UAS significantly improved stone clearance regardless of the type of laser or URS used (p<0.01). CONCLUSIONS: sTFL when combined with a 14F UAS, a dual lumen ureteroscope, and endoscopic suction resulted in a 94% stone clearance rate. Source of Funding: UCI Endourology Lab Fund © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e1120-e1120 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Pengbo Jiang More articles by this author Akhil Peta More articles by this author Raphael Arada More articles by this author Maged Ayad More articles by this author Andrew Afyouni More articles by this author Luke Limfuenco More articles by this author Andrew Brevik More articles by this author Nicholas Nguyen More articles by this author Zhamshid Okhunov More articles by this author Roshan Patel More articles by this author Jaime Landman More articles by this author Ralph Clayman More articles by this author Expand All Advertisement Loading ...

Transportation, turning and installation of the pedestal and column on the Palace Square in St. Petersburg

The materials are devoted to the consideration of the issues of transportation, edging and installation of the pedestal and the column on the Palace Square in St. Petersburg. In addition to the album of illustrations by A. Montferrand, the drawings of Adamini Antonio, Montferrand's assistant, are considered, clarifying some aspects of the ascent. The questions about lifting the Alexander Column sometimes include doubts about the possibility of processing a large granite massif without the use of mechanical equipment. However, familiarity with the methods of manual stone processing presented in various works should convince the reader of the infinite possibilities of a person with a chisel and a hammer, especially if you add to them the perseverance, ingenuity and resourcefulness of the Russian person. In addition, we should remember a somewhat forgotten, but highly respected word -master. The most responsible and spectacular work was the lifting of the Alexander Column, which was the result of a lot of preparatory works. The construction of the platform and the inclined overpass was only part of them. A stone mass was built around the pedestal, which served as the basis for placing the capstans in two concentric circles. After the installation of the column, the finishing of the monument to the final dimensions, grinding and installation of the angel on the top were carried out for two years. Very little is known about these operations, but the presence of scaffolds made it possible to perform work at any height in any weather, and the possibility of processing granite and diabase, and their grinding has already been recalled. The installation of the angel sculpture without the use of hydraulic cranes and helicopters is hopefully no longer in doubt. The next day after the installation, they began to disassemble all the wooden structures. Stairs were built around the main vertical risers. After installation, the stonemasons continued to work with the column. For several months, more than 200 people worked simultaneously. They cut the belts left on the monolith for rolling and lifting, carried out the final finishing according to precise patterns and polished the stone. This article is devoted to the attempt to mathematically justify the possibility of what was achieved at the level of knowledge, skills, mechanisms and technologies of the beginning of the 19th century.

Comparative outcomes of flexible ureteroscopy and mini-percutaneous nephrolithotomy for pediatric kidney stones larger than 2cm.

To compare the outcomes of flexible ureteroscopy and mini-percutaneous nephrolithotomy for pediatric kidney stones larger than 2cm and to show the learning curves for the two procedures. A prospectively managed database containing pediatric patients with kidney stones larger than 2cm from June 2014 to October 2019 was analyzed. The primary outcomes were the efficacy and safety of flexible ureteroscopy and mini-percutaneous nephrolithotomy. Data on patient demographics, treatment details, stone-free rate, and complication rate were collected and compared. Learning curves were generated to estimate the effect of the surgeon's experience on surgical outcomes. The final analysis included 113 pediatric patients who underwent surgery for kidney stones on a total of 126 sides. The stone-free rates for mini-percutaneous nephrolithotomy and flexible ureteroscopy were 80.9% (34/42) and 79.7% (67/84), respectively (P=0.19). The complication rates for mini-percutaneous nephrolithotomy and flexible ureteroscopy were 52.5% (21/40) and 27.4% (27/73), respectively (P=0.01). When stone mass was considered, the stone-free rates for mini-percutaneous nephrolithotomy and flexible ureteroscopy for stones with a high mass (>5000 HU*cm2 ) were 83.3% (20/24) and 55.5% (10/18), respectively (P=0.04). The learning curves showed that the stone-free rates for both mini-percutaneous nephrolithotomy and flexible ureteroscopy increased with the accumulation of cases. A higher stone-free rate could be achieved after approximately 20 mini-percutaneous nephrolithotomy cases and after approximately 50 flexible ureteroscopy cases. Flexible ureteroscopy has an acceptable stone-free rate and a lower complication rate than mini-percutaneous nephrolithotomy when treating pediatric kidney stones larger than 2cm. Mini-percutaneous nephrolithotomy is more applicable to stones with a high mass. The stone-free rates achieved after both mini-percutaneous nephrolithotomy and flexible ureteroscopy could be improved with number of cases accumulated.

In Vitro Dusting Performance of a New Solid State Thulium Laser Compared to Holmium Laser Lithotripsy.

Purpose: To examine the dusting performance of a novel solid state Thulium laser device compared to a standard holmium:yttrium-aluminum-garnet (Ho:YAG) device. Methods: This study compares a Dornier Medilas H Solvo 35 with an evaluation model of a pulsed solid state thulium:yttrium-aluminum-garnet (Tm:YAG) laser (Dornier MedTech Laser GmbH, Wessling, Germany). The in vitro model consisted of a mold with irrigated water at 37°C. For 2-9 minutes, laser fibers were guided by an xy-plotter in spirals over BegoStones. Stone mass was measured before and after laser application. Comparisons to Ho:YAG and further Tm:YAG investigations were performed. Results: Identical settings with similar pulse durations yielded a significant 14% advantage for Ho:YAG in slow fiber speeds and a tendency toward 15% higher efficiency of Tm:YAG in fast fiber speeds. Increased pulse duration in Tm:YAG led significantly to 32%-54% higher ablation rates in comparison to Tm:YAG in both setups. Ablated mass loss range is 102-1107 mg for slow fiber speeds and 22-528 mg for fast speeds. Mass loss is proportional to pulse energy, frequency, and pulse duration, whereas pulse energy defines the penetration depth into the model stones. Frequency characterizes the ablation homogeneity and possible working speeds. Conclusion: Tm:YAG is significantly more efficient when longer pulse durations are used. Identical settings revealed a strong connection to fiber movement speeds. In addition, the Tm:YAG device enables a broader range of settings with the possibility of minimal pulse energy of 100 mJ for low retropulsion and fine dusting with possible frequencies ≤200 Hz.

On the characteristic heating and pyrolysis time of thermally small biomass particles in a bubbling fluidized bed reactor

Abstract Pyrolysis of crushed olive stone particles in a lab scale Bubbling Fluidized Bed (BFB) reactor was investigated. The time evolution of the pyrolysis conversion degree of the olive stone particles, while moving freely in the BFB, was determined from the evolution of the mass of olive stones remaining in the bed, measured by a precision scale holding the whole reactor installation. The experimental measurements of the pyrolysis conversion degree were employed to validate a simple model combining heat transfer and chemical kinetics, which is valid for thermally small particles. The model combines the Lumped Capacitance Method (LCM) and the simplified Distributed Activation Energy Model (DAEM) to account for heat transfer and pyrolysis chemical kinetics, respectively. The estimations of the combined LCM-DAEM model for the pyrolysis conversion degree were found to be in good agreement with the experimental measurements for the pyrolysis of olive kernels in a BFB operated at various bed temperatures, fluidizing gas velocities, and biomass particle size ranges. From the combined LCM-DAEM model, the characteristic heating time and the pyrolysis time of the olive stone particles were derived, obtaining a direct relation between these two parameters for constant values of the bed temperature.

Assessment of the method for abrasion resistance determination of sandstones on B\xf6hme abrasion test apparatus

The article analyses the method of testing the abrasion resistance of sandstones on Böhme abrasion test apparatus and describes the problems related to the implementation of this test, as well as the interpretation of the results. The tests were conducted in accordance with the requirements of the EN14157 standard on 14 samples of dry and water-saturated sandstones. The analysis of the results showed that the correlation coefficient for the results obtained in the case of dry samples tests in relation to water saturation was 0.944. It was also observed that the loss of volume during the abrasion process in the individual stages of the test is smaller with the increase of rotation on the disc. In the case of dry samples abrasion, the reason for this is the mixing of abrasive grain and worn stone. In the case of samples tested under conditions of water saturation, the sample is covered with the abrasive grain, which in further phases is liquefied and mixed with the worn stone mass. In this case, however, the abrasion is worse in comparison with the samples tested in the dry condition, because the liquid and mixed abrasive grain with the worn rock mass causes the sample to slide, which in turn results in the abrasion volume loss. The control of the abrasion resistance results obtained from the stone abrasion according to the EN14157 standard should be a comparison with the abrasion resistance results obtained in the process of calculating the abrasion volume loss of sample determined from height.

Distinct perceptuomotor features of percussive tooling in humans (Homo sapiens) and wild bearded capuchin monkeys (Sapajus libidinosus).

Adjustment of percussive movements to match the energetic requirements of the task serves as an index of skill in stone-knapping and nut-cracking. In this study, we compared strike-by-strike adjustment of percussive movements in expert bearded capuchin monkeys (Sapajus libidinosus) and (novice and expert) humans cracking palm nuts (Astrocaryum spp.) using stone hammers of varying mass. The monkeys regulated each strike's amplitude and hammer's velocity at impact to a small degree based on the propagation of a fracture in the nut's shell but overall struck a nut with consistent kinetic energy for a given hammer. They showed the smallest movement variability across strikes among all groups. Novice humans took the most strikes to crack a nut among all groups. Expert humans took the fewest strikes among all groups while showing the largest variation in hammer's kinetic energy at impact and largest movement variability across strikes. Overall, our findings confirm that expert humans can adjust their strikes more precisely to meet variable task demands and are more efficient than monkeys or novice humans in cracking nuts, but the findings also show a surprising advantage for expert monkeys over novice humans. The monkeys' strategy of striking with consistent amplitude and velocity is advantageous when hammer mass is adequate to generate sufficient kinetic energy at impact and crack open a nut in few strikes without requiring fine adjustments, explaining why the monkeys are particularly attentive to a stone's mass when choosing it as a hammer. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

How Lasers Ablate Stones: In Vitro Study of Laser Lithotripsy (Ho:YAG and Tm-Fiber Lasers) in Different Environments.

Introduction: There are two main mechanisms of stone ablation with long-pulsed infrared lasers: photothermal and photomechanical. Which of them is primary in stone destruction is still a matter of discussion. Water holds importance in both mechanisms but plays a major role in the latter. We sought to identify the prevailing mechanism of stone ablation by evaluating the stone mass loss after lithotripsy in different media. Materials and Methods: We tested a holmium:yttrium-aluminum-garnet (Ho:YAG) laser (100 W; Lumenis), a thulium-fiber laser U1 (TFL U1) (120 W; NTO IRE-Polus, Russia), and a SuperPulse thulium-fiber laser U2 (TFL U2) (500 W; NTO IRE-Polus). A single set of laser parameters (15 W = 0.5 J × 30 Hz) was used. Contact lithotripsy was performed in phantoms (BegoStones) in different settings: (a) hydrated phantoms in water, (b) hydrated phantoms in air, (c) dehydrated phantoms in water, and (d) dehydrated phantoms in air. Laser ablation was performed with total energy of 0.3 kJ. Phantom mass loss was defined as the difference between the initial phantom mass and the final phantom mass of the ablated phantoms. Results: All lasers demonstrated effective ablation in hydrated phantoms ablated in water; no visual differences between the lasers were detected. The ablation of dehydrated phantoms in air was also effective with visible vapor during ablation and condensation on the cuvette wall. Dehydrated phantoms in water and in air show minimal to no ablation accompanied with formation of white crust on phantom surface. Among laser types, TFL U2 had the highest phantom mass loss in all groups except for dehydrated phantoms ablated in air. Conclusions: Our results suggest that both photothermal and thermomechanical ablation mechanisms (explosive vaporization) occur in parallel during laser lithotripsy. In Ho:YAG and TFL U2 stone ablation explosive vaporization prevails, whereas in TFL U1 ablation photothermal mechanism appears to predominate.

Some morphological traits of the fruit and apricot stone of Dagestan origin at the different ripening periods

The paper presents the results of a comparative study of the cultivated and wild-growing apricot of Dagestan origin according to the morphological characteristics of the fruit and stone at different ripening periods. The pomological evaluation showed that the shape index of the fruit changes by one gradation regardless of the origin of the genotype, while the shape of the stone does not change and remains constant for all genotypes. For example, the fruit of the Kamil cultivar has an ovate shape at an early ripening period, and a circular one at late ripening. During ripening, the weight of the fruit doubles (1.8–2.6 times), while the ratio of stone mass to the weight of the fruit decreases (1.8–2.5 times). For cultivars and wild-growing forms, differences in the change in the linear dimensions and mass of the stone at different maturation periods were noted. The morphological characteristics of the fruit and stone in terms of the coefficient of variation (CV) vary more at the later stages of ripening, and in general are higher in cultivars than in wild plants, and the endocarp varies less than the fruit, at all periods of ripening.

Comparison of first-generation (1908 nm) and second-generation (1940 nm) thulium fiber lasers for ablation of kidney stones

Thulium fiber lasers (TFL) are being developed as alternatives to conventional holmium:YAG lasers for lithotripsy. TFLs emit at two primary infrared (IR) wavelengths, 1908 or 1940 nm, closely matching high (70°C) and low (22°C) temperature water absorption peaks in tissue, respectively. Water, which is present in the pores of kidney stones and fluid environment of the urinary tract as well as delivered through the working channel of the ureteroscope during lithotripsy, is a primary absorber of IR laser radiation. The water absorption peak shifts from 1940 to 1920 nm with increasing water temperature during laser ablation. At high water temperatures (70°C), the absorption coefficient is 150 cm − 1 at 1908 nm and 135 cm − 1 at 1940 nm. The goal of this study was to determine whether this 10% difference translates into a measurable difference in kidney stone ablation rates. Two TFLs (1908 and 1940 nm) were tested at similar laser parameters of 35 mJ energy/pulse, 500-μs pulse duration, 300-Hz pulse rate, and 10.5-W average power, using 200-μm-core silica optical fibers. The handheld fiber was maintained in contact with 6- to 9-mm diameter uric acid (UA) stones, immersed in a saline bath with saline flow ( n = 10 stones / group). Laser irradiation time to fragment and pass all stone fragments through a 1-mm sieve was measured and then divided into initial stone mass to calculate stone ablation rates. For each laser group (1908 and 1940 nm), initial stone mass was 270 ± 60 mg versus 260 ± 50 mg, respectively ( p = 0.9). Stone ablation rates measured 0.9 ± 0.2 and 0.9 ± 0.1 mg s − 1 ( p = 0.9). Stone ablation thresholds measured 8 ± 7 and 5 ± 13 J cm − 2 ( p = 0.8). There was no significant difference in UA stone ablation thresholds and ablation rates between 1908- and 1940-nm wavelengths. Newer, more compact, efficient, and higher peak power TFLs operating at 1940 nm provide comparable stone ablation rates to older 1908-nm TFLs for similar laser parameters.

Are We Cutting Ourselves Short? Laser Lithotripsy Performance Based on Differences in Fiber-tip Preparation

ObjectiveTo better understand the impact of laser fiber-tip configuration on lithotripsy performance, we undertook an in vitro study comparing 3 fiber-tip configurations: (1) new (single-use), (2) cleaved (reusable), and (3) coated (cut with scissors). MethodsLithotripsy was performed using a Ho:YAG laser utilizing fragmentation (1 J × 10 Hz) and dusting (0.5 J × 20 Hz) settings. BegoStones were fragmented with a laser fiber advancing at a speed of 1 mm/s (220 seconds of activation). Three fiber-tip configurations were tested: new single-use standard (242 μm core) and cleaved (272 μm core), compared to the same fiber-tip coated/cut flush with scissors, respectively. Study outcome was difference in stone mass before and after each experiment. Power output was measured using a power meter. ResultsFragmentation for new or cleaved fibers was greater than the coated/cut flush fiber-tip (P <.05). For 1 J × 10 Hz and 0.5 J × 20 Hz settings, fragmentation was 59% and 75% higher with new fiber-tip compared to the coated/cut flush fiber-tip, respectively. For 1J × 10 Hz and 0.5 J × 20 Hz settings, fragmentation was 51% and 45% higher with cleaved fiber-tip compared to the coated/cut flush fiber-tip, respectively. Power output at the end of laser activation was higher for new and cleaved fiber-tips. ConclusionNew and cleaved laser fibers demonstrated superior lithotripsy performance compared to fibers that were coated/cut flush with scissors. Cutting single-use laser fibers risks damaging the fiber-tip which can disperse the energy and reduce lithotripsy efficiency.

Ex vivo testing of air-cooled CW/modulated 30 W thulium fiber laser for lithotripsy.

A diode-pumped, air-cooled, all-fiber, quasi-continuous-wave thulium laser at an operating wavelength of 1.94μm has been designed to study the performance of the laser parameter on the rate of fragmentation and its dependence on stone composition, fragmented particle size, as well as the retropulsion effect. The optimized laser cavity with an active fiber core/cladding diameter of 10/130μm under a counter-propagating pump provides a stable laser power of 30W at a slope efficiency of 50% and wall plug efficiency of 17%. The rate of fragmentation along with the retropulsion effect has been studied with human calcium oxalate monohydrate (COM) urinary stones (N=36) of different composition by using the designed laser and 200-μm-core low OH silica delivery fiber. The thulium fiber laser setting of 2.7J pulse energy at the pulse rate of 10Hz, pulse width of 90ms, and peak power of 30W is successful in breaking human COM stones in a controlled manner at a fragmentation rate of 0.8±0.4 mg/s, with almost uniform fragments of particle size less than 1.6mm. During the stone fragmentation, the stone displacement (retropulsion effect) is less than 15mm, even for the fragmented stone mass of 15±5 mg.

The Path of the First European Porcelain Wares to Lithuanian Museums

The state’s development, twists and turns of culture and history of the country, circumstances and passing time, often erase facts, that is why the reconstruction of the history of exhibits’ acquisition in museums is one of the most complicated aspects in museology. The article is dedicated to the presentation of Johann Friedrich Böttger’s (1682-1719) collection of red stone mass exhibits in Lithuanian museums and aims at revealing their history. Thanks to the archival register, it was possi­ble to discover the inventory lists with descriptions of valuable works of art that had been prevented from being seized by Germans and pre­served during the Soviet occupation. Among them, there were exhib­its stored at the M.K. Čiurlionis National Museum of Art. Particularly valuable are twelve items of red stone mass by J.F. Böttger. Their iden­tification revealed not only the date (1940) and the manor (the Pakruo­jis manor, Šiauliai region, Lithuania) from which the nationalized art collection was transferred to the museum but also to whom [Leo Carl von der Ropp (27.09.1860 Pakruojis – 09.10.1940 Berlin)] it belonged. That is how the history of J.F. Böttger’s red stoneware exhibits has been unveiled. The Lithuanian Art Museum purchased two exhibits from private persons (1980 and 1982).

Evaluation of Renal Stone Comminution and Injury by Burst Wave Lithotripsy in a Pig Model.

Introduction: Burst wave lithotripsy is an experimental technology to noninvasively fragment kidney stones with focused bursts of ultrasound (US). This study evaluated the safety and effectiveness of specific lithotripsy parameters in a porcine model of nephrolithiasis. Methods: A 6- to 7-mm human kidney stone was surgically implanted in each kidney of three pigs. A burst wave lithotripsy US transducer with an inline US imager was coupled to the flank and the lithotripter focus was aligned with the stone. Each stone was exposed to burst wave lithotripsy at 6.5 to 7 MPa focal pressure for 30 minutes under real-time image guidance. After treatment, the kidneys were removed for gross, histologic, and MRI assessment. Stone fragments were retrieved from the kidney to determine the mass comminuted to pieces <2 mm. Results: On average, 87% of the stone mass was reduced to fragments <2 mm. In three of five treatments, stones were completely comminuted to <2-mm fragments. In two of five treatments, stones were partially disintegrated, but larger fragments remained. One stone was not treated because no suitable acoustic window was identified. No injury was detected through gross, histologic, or MRI examination in the parenchymal tissue, although petechial damage and surface erosion were identified on the urothelium of the collecting system limited to the area around the stone. Conclusion: Burst wave lithotripsy can consistently produce stone fragments small enough to spontaneously pass by transcutaneous administration of US pulses. The data suggest that such exposures produce minimal injury to the kidney and urinary tract.

Investigating the effect of pumice stones sensible heat storage on the performance of a solar still

In this communication, a single slope basin type solar still is investigated for the climatic conditions of Aligarh (27.89° N, 78.08° E), India. The solar still was tested for the change in the amount of energy storage material (pumice stones) for a constant amount of water (10 L) in the basin. An experiment was initially conducted without any energy storage material and was later compared with the experimental data of solar still with 5 kg and 10 kg pumice stones. Daytime yield for the solar still without energy storage material was found to be 1950 ml; and decreased for solar stills with 5 kg and 10 kg pumice stones as 1748 and 1618 ml of distillate, respectively. The productivity of the solar still during nighttime enhanced due to energy storing capacity of pumice stones but the overall production reduced by increasing the mass of pumice stones. Further, the three cases were also compared on the basis of heat transfer coefficients from water to glass, and glass to the ambient. The overall thermal efficiency of the solar still with no mass, 5 kg and 10 kg pumice stones was found to be 35.1%, 29.3% and 28.8% respectively.