Soft Stone Research Articles

Benchtop and Initial Clinical Evaluation of the ShockPulse Stone Eliminator in Percutaneous Nephrolithotomy.

Standardized bench testing of the new ShockPulse™ intracorporeal lithotripter was performed against three commercially available lithotripsy systems to determine differences and nuances in performance. The ShockPulse intracorporeal lithotripter was tested against the LUS-2™, CyberWand,™ and EMS LithoClast™ in a standardized bench setting using hard (Ultracal-30) and soft (plaster of Paris) stone phantoms. An in vitro kidney model was used to record the time needed to fragment stone samples into retrievable-sized pieces. The time needed to fully comminute and evacuate stone samples was also recorded. The efficacy of each device at various applied pressures was determined using a hands-free apparatus, which was used to apply 1.0, 1.5, and 2.0 pounds of fixed force. For hard and soft stones, the time needed to create retrievable fragments was similar among all systems (p = 0.585). The ShockPulse was significantly faster than the LUS-2 and LithoClast at fully fragmenting and evacuating stone samples (p = 0.046), while the CyberWand was significantly slower than all three systems at this task (p = 0.001). When fixed forces were applied to a large stone phantom, the ShockPulse and CyberWand were significantly faster than the LUS-2 and LithoClast (p < 0.0001). When groups of smaller stones were tested, the ShockPulse was significantly faster at 1.0 pound (p < 0.001) and 1.5 pounds (p < 0.002) of force. At 2.0 pounds, no differences were observed (p = 0.09). The ShockPulse is equally as effective and, in some circumstances, more effective than the three commercially available devices against which it was tested in an in vitro setting.

Endoscopic ultrasound as a predictor and guide to successful endotherapy in chronic pancreatitis

Background:Pancreatic calculi are sequelae of chronic pancreatitis (CP) and may obstruct pancreatic ducts leading to pain. Indications for endotherapy include nonimpacted <5 mm stones in the head of pancreas with the absence of downstream strictures. The assessment before endotherapy is done by magnetic resonance cholangiopancreatography/computed tomography.Objectives:To assess the modality of endoscopic ultrasound (EUS) as a roadmap before endoscopic retrograde cholangiopancreatography (ERCP) in patients planned for endotherapy in CP.Methods:The data of 412 patients with CP were retrospectively analyzed. A total of 143 were associated with stones in the head/papillary region of pancreas. Of these, around 75 were excluded and remaining 68 were evaluated by EUS using a linear/radial echoendoscope before ERCP.Results:Of 68 cases, 48 were associated with hard stones with acoustic shadowing while twenty were associated with soft stones without acoustic shadowing. In twenty soft stones cases, ERCP was successful in 18 patients. In 48 patients with hard stones, there was failure of endotherapy in forty patients which required extracorporeal shock wave lithotripsy/surgery. The presence of large, hard, immobile stones was negative predictors of successful endotherapy. Small, ampullary/papillary stones were positive predictors.Conclusions:EUS can influence therapeutic decisions before endotherapy and can prevent unsuccessful attempts improving overall success/prognosis. EUS has an additional advantage of making a diagnosis of ampullary/papillary stones and biliary obstruction which can be treated endoscopically. It can guide whether endotherapy needs to be performed through major or minor papilla. EUS by diagnosing pancreatic tumor/strictures missed on other imaging modalities allows early surgical reference and hence improves long-term prognosis.

Endoscopic ultrasound as a predictor and guide to successful endotherapy in chronic pancreatitis

Background and Objectives:Pancreatic calculi (PCs) are sequelae of chronic pancreatitis (CP) and may obstruct and produce ductal hypertension leading to pain, the cardinal feature of CP. Indications for endotherapy include stones <5 mm size, stones in the head of pancreas which are not impacted and absence of downstream strictures. The assessment before the procedure is done by magnetic resonance cholangiopancreatography (MRCP) or computed tomography (CT). However, problems are encountered during endoscopic retrograde cholangiopancreatography (ERCP) clearance which are not anticipated despite MRCP/CT. The problems are possible impacted stones, hard stones, indeterminate stricture, and change of finding during ERCP. Hence, controversy exists. Endoscopic ultrasound (EUS) can help by providing concordance or discordance with MRCP images and may help in further clarification. The aim of this study is to evaluate the role, feasibility, and management changes of EUS before ERCP in patients planned for endotherapy in CP. Another objective was to evaluate whether EUS features of pancreatic duct (PD) stones can serve as a predictor of successful removal during ERCP.Methods:The data of 412 patients during the study period (2009–2016) with CP were retrospectively analyzed. A total of 143 were associated with stones in head/papillary region of pancreas. Out of these, 75 were excluded and remaining 68 were evaluated by EUS using a linear/radial echoendoscope before ERCP.Results:Out of 68 cases, 48 were associated with hard stones with acoustic shadowing while 20 were associated with soft stones without acoustic shadowing. In 20 soft stones cases, ERCP was successful in 18 patients. In 48 with hard stones, there was failure of endotherapy in 40 which required extracorporeal shock wave lithotripsy (ESWL)/surgery. The presence of large (≥5mm), hard, immobile stones were negative predictors of successful endotherapy. Small, ampullary/papillary stones were positive predictors.Conclusion:The present study suggests that EUS can differentiate “soft PD stones” (without an acoustic shadow) from “hard PD stones”(with acoustic shadow). “Hard PD stones” are better managed by ESWL. An EUS can influence important therapeutic decisions before endotherapy and can prevent unsuccessful attempts at ERCP and thus improve overall success/prognosis. An EUS has an additional advantage of making a diagnosis of ampullary/papillary stones and biliary obstruction which can be treated endoscopically. It can guide whether endotherapy needs to be performed through major or minor papilla. EUS by diagnosing pancreatic tumor/strictures missed on other imaging modalities allows early surgical reference and hence improves long term prognosis.

Operational modal analysis for the characterization of ancient water towers in Pompeii

In the framework of an investigation campaign carried out in June 2015 by the authors on four ancient water towers (10–20 BC) in the archaeological site of Pompeii, modal analysis and output-only identification techniques were employed to extract the dynamic properties in order to assess structural vulnerabilities and support numerical model updating.The four investigated towers (selected among the fourteen present within the archaeological site) are free-standing structures at least 6 m tall, belonging to the Castellum Aquae, i.e. the ancient aqueducts system of the city. During the Roman Age, until the destruction of Pompeii due to the volcanic eruption in 79 AD, water towers provided fresh water to houses, palaces and villas. This particular type of structures are classified as no. 1, 2, 3 and 4 by archaeological literature: no. 1 and 4 are made of soft stone masonry (tuff, limestone), while no. 2 and 3 are composed by brickwork masonry.The paper reports the outcomes of ambient vibration tests performed on four towers in terms of extracted modal parameters using various operational modal analysis techniques. Obtained data are then used to study numerically the soil-structure interaction problem and implement model updating procedures.

Trends and consequences of consumption of food and non-food items (pica) by pregnant women in Western Kenya

Pregnancy is a memorable experience for every woman and it comes with many changes which include cravings for food and non-food items. The aim of this study was to explore the change in diet in terms of pica, food craving and aversions which occur during pregnancy. Two hundred and two pregnant women were interviewed. Food craving was reported by 73.8% of the study participants and nearly half (48.7%) had food aversions. Foods craved most were maize meal (12.5%), mangoes (9.5%), ripe banana (8.3%), beef (7.6%) and fish (5.7%). Foods avoided most were small fish (omena) (15.2%), beef (12.6%), kale (11.9%) and fish in general (10.6%). Eggs, tea and milk were also avoided. Reasons given for avoiding certain foods were: to prevent nausea (45.8%), vomiting (21.9%) and heartburn (10.4%). Other reasons given were unpleasant smell/taste and stomach ache. Pica prevalence was at 27.4%, with consumption of soil and soft stones being frequently reported. There was a highly significant association between level of education (p=0.02) and history of child death/still birth (p=0.01) with pica.Food cravings, aversions and pica practices should be assessed in antenatal care of pregnant women. Attention should be paid to pregnant women who have had a history of child death and women with low education level.

Impact of Stone Density on Percutaneous Nephrolithotomy Outcomes with a Dual Frequency Ultrasonic Lithotripter: Computerized Tomography Based Outcomes at a Low Volume Center

IntroductionWe studied the safety and efficacy of the CyberWand™ lithotripter and how stone density affects the efficacy. MethodsWe retrospectively analyzed the outcomes of percutaneous nephrolithotomy performed using the CyberWand dual frequency ultrasonic lithotripter at our institution between November 2009 and July 2015. A total of 63 procedures were performed on 57 renal units and, thus, we may be considered a low volume center. We assessed the outcomes of each renal unit in terms of the clinically insignificant residual fragment rate, complication rate, operating room time, estimated blood loss and length of hospitalization. We evaluated the effect of HU of the stone (less than 1,000 HU considered soft and greater than 1,000 HU considered hard) on outcome. ResultsOur outcomes using the CyberWand lithotripter were comparable to those of other lithotripsy modalities in terms of the complication rate and clinically insignificant residual fragment rate. We achieved clinically insignificant residual fragment status (defined as less than 4 mm residual stone size) in 54% of renal units and the overall complication rate was 24%. There were no appreciable differences between soft stones and hard stones in terms of any outcome parameter including complication rate, clinically insignificant residual fragment rate and operative time. ConclusionsThe CyberWand lithotripter is an acceptable, noninferior modality of percutaneous lithotripsy of renal calculi. The efficacy of the CyberWand lithotripter is not affected by stone density.

ZOOMORPHIC EFFIGY PENDANTS: AN EXAMINATION OF STYLE, MEDIUM, AND DISTRIBUTION IN THE CADDO AREA

Caddo zoomorphic effigy pendants were crafted from a wide variety of raw material, such as freshwater mussel shell, Busycon perversum (whelk) marine shell, animal bone, and various types of soft stone. They have been documented at contemporaneous Late Caddo (A.D. 1400–1700) sites along the Red River in northeast Texas, southwest Arkansas, and northwest Louisiana; the Black Bayou, Big Cypress Bayou, and upper Sabine River basins in northeast Texas; the Ouachita River in south-central Arkansas; and the Arkansas River in central Arkansas and eastern Oklahoma. This paper describes the development of a comprehensive corpus that investigates stylistic groups, differential raw material or medium utilized, and the spatial distribution of zoomorphic effigy pendants throughout the Caddo area. Results reveal north-south heterogeneity, suggesting the presence of broader traditional cultural narratives associated with a complex idea that is manifest regionally in distinct stylistic forms and linked to Caddo beliefs concerning Beneath World themes. Additionally, this stylistic and spatial analysis offers an additional dataset to further explore social, political, and economic linkages among and between contemporary Caddo groups around A.D. 1500.

Unusual encrusted cystitis by Escherichia Coli(Case Report)

Bladder calculi have been observed in men with urinary stasis. Especially, bladder calculi induced irritative voiding symptomssuch as frequency, nocturia, and obstructive voiding symptoms such as hesitancy, post ?voiding dribbling . We report anunusual case of 64-year-old male with soft bladder stone and will briefly discuss the management.

Milk of calcium stones: radiological signs and management outcome.

Milk of calcium (MOC) is a rare type of stone that was first described in 1940 by Ludin and Howald who reported MOC in renal cysts. Milk of calcium is a viscous colloidal suspension of calcium salts. Stasis, obstruction and infection are important predisposing factors. Due to a layering effect, characteristic radiological signs especially in CT can help in diagnosis to avoid unsuccessful shock wave lithotripsy. This is the largest reported case series, in which radiological signs by CT scan to predict renal MOC stones, clinical picture and management outcome are described in detail. Cases with suspected renal milk of calcium stones were studied over 7 years (2008-2015). All cases were diagnosed preoperatively by non-contrast CT. Urine cultures were performed in all patients preoperatively. Intra-operative and postoperative findings were reported. Stones retrieved were sent for chemical analysis using an infrared method. Seven cases of milk of calcium renal stones were included in this study. These stones were faint radio-opaque in two cases and radiolucent in five cases. All cases were diagnosed preoperatively with non-contrast CT. Their Hounsfield units (HU) ranged from 114 to 612. All stones were located in a dependent position (gravitational effect) in the posterior aspect of dilated calyces. Five cases exhibited the typical fluid level and two cases demonstrated semilunar (half moon) pattern in the anterior surface of the stones. All cases underwent PCNL with suction and retrieval of soft stones without the need for disintegration. When stones demonstrate a low Hounsfield unit, are arranged in dependent positions within dilated calyces and exhibit fluid level or semilunar pattern on non-contrast CT, milk of calcium stones should be considered. PCNL is an effective modality for management of renal milk of calcium stones.

The role of the petrophysical characteristics on the durability and conservation of some porous calcarenites from Southern Italy

Abstract Highly porous and soft calcarenites, often called ‘calcareous tuffs’, are commonly found throughout Southern Italy and are traditionally used as building materials. The petrophysical features of some of them were determined, focusing on the microstructure (fabric and porosimetric characteristics) and on the properties related to water absorption, drying and water vapour permeability; the compressive strength was also measured. The mineralogical composition was analysed and a variable presence of clay minerals was found for the different varieties. Diverse levels of damage under a salt crystallization test were related to the mineralogical, petrographic and porosimetric features, the latter being a source of the heterogeneity of the investigated stones. Results of laboratory tests and observations of decay in the field suggest protection against water penetration as the primary requirement for slowing down the decay of such highly porous and soft stones. Some water-repellent products were tested for effectiveness in reducing water absorption and for compatibility with the original stones’ properties. Their use in the presence of salts was taken into account, including the performances of the treated stones under the salt crystallization test. Treatment issues were found to be strongly influenced by the porosimetric characteristics of the studied materials.

Heavy metals and parasitic geohelminths toxicity among geophagous pregnant women: a case study of Nakuru Municipality, Kenya.

Geophagia is defined as deliberate consumption of earths' materials, e.g. soil, clay and soft stones. The practice is widespread among pregnant women, and there are conflicting views as to whether it is beneficial to health or not. Geophagic materials may be a source of micronutrients though the materials may bind the micronutrients thus reducing or hindering their bioavailability in the body. Geophagia is closely associated with geohelminthic infections among pregnant women and heavy metal poisoning, which constitute significant public health problem in many developing countries such as Kenya. In our research, the geophagic materials consumed by the pregnant women were studied. A total of 38 geophagic materials in the possession by different pregnant women were analysed. The collected samples were subjected to standard digestion procedures and analysed for zinc, lead and iron by atomic absorption spectroscopy. Results indicated that the geophagic materials contained elevated levels of Fe at mean concentration value of 80.10ppm, Pb at 3.28ppm and Zn 1.81ppm for a 1.00g sample. An average of 20g of the geophagic materials was being consumed per day. Based on the average consumption, the pregnant women were exposed to 65.52ppm Pb per day, 36.2ppm Zn per day and 1602ppm Fe per day. Lead exceeded the WHO-lead exposure limits of 25ppm/day for pregnant women. The materials were also subjected to microscopic examination for Ascaris lumbricoides, Trichuris trichiura, Taenia Spp., Necator americanus and Ancylostoma duodenale. In conclusion, the women were exposed to heavy metals-iron, zinc and lead, but there was no observable eggs, larvae or adult species of the geohelminths. The key recommendation was that there is need to integrate public health education on geophagia, lead screening and testing with antenatal support care systems. This will enhance maternal and child health, thus reducing infant and maternal morbidity and mortality rates.

Données inédites sur le Gravettien oriental : apport de la technologie osseuse à la caractérisation des occupations de Kostienki 4 (Alexandrovska, région de Voronej, Russie)

Le Gravettien oriental est encore trop souvent réduit à sa manifestation la plus spectaculaire : la «culture de Kostienki-Avdeevo » . Certains sites ont pourtant livré des industries lithiques qui s’en démarquent très nettement. C’est le cas du gisement de Kostienki 4 auquel nous consacrons cette étude. Ce site a livré deux occupations généralement rapportées au Gravettien lato sensu, et prenant place entre 21000 et 23000 uncal. BP. L’ancienneté des fouilles, autant que l’absence d’études archéozoologiques rendent la documentation disponible souvent parcellaire. En confrontant, pour la première fois, les données inédites de l’industrie en matières dures d’origine animale de Kostienki 4, aux autres sphères de la culture matérielle, nous avons pu mettre en évidence de nouveaux éléments de caractérisation de ses deux phases d’occupation. Nous verrons que ce sont des groupes indubitablement différents qui s’y sont succédés, et probablement à différentes saisons de l’année. Des différences majeures transparaissent dans les matières osseuses exploitées, dans leur transformation et leur utilisation, questionnant sur la pertinence d’un rattachement de ces deux niveaux d’occupation à une même entité culturelle. Enfin, les différences observées entre les deux habitats du niveau inférieur, nous permettront de discuter d’une éventuelle différentiation fonctionnelle ou sociale de l’espace.

Systematic evaluation of a holmium:yttrium-aluminum-garnet laser lithotripsy device with variable pulse peak power and pulse duration

ObjectiveThe Holmium:yttrium-aluminum-garnet (Ho:YAG) laser is the standard lithotrite for ureteroscopy. This paper is to evaluate a Ho:YAG laser with a novel effect function in vitro, which allows a real-time variation of pulse duration and pulse peak power. MethodsTwo types of phantom calculi with four degrees of hardness were made for fragmentation and retropulsion experiments. Fragmentation was analysed at 5 (0.5 J/10 Hz), 10 (1 J/10 Hz), and 20 (2 J/10 Hz) W in non-floating phantom calculi, retropulsion in an ureteral model at 10 (1 J/10 Hz) and 20 (2 J/10 Hz) W using floating phantom calculi. The effect function was set to 25%, 50%, 75%, and 100% of the maximum possible effect function at each power setting. Primary outcomes: fragmentation (mm3), the distance of retropulsion (cm); ≥5 measurements for each trial. ResultsAn increase of the effect feature (25% vs. 100%), i.e., an increase of pulse peak power and decrease of pulse duration, improved Ho:YAG laser fragmentation. This effect was remarkable in soft stone composition, while there was a trend for improved fragmentation with an increase of the effect feature in hard stone composition. Retropulsion increased with increasing effect function, independently of stone composition. The major limitations of the study are the use of artificial stones and the in vitro setup. ConclusionChanges in pulse duration and pulse peak power may lead to improved stone fragmentation, most prominently in soft stones, but also lead to increased retropulsion. This new effect function may enhance Ho:YAG laser fragmentation when maximum power output is limited or retropulsion is excluded.

A sealed flint knapping site from the Younger Dryas in the Scheldt valley (Belgium): Bridging the gap in human occupation at the Pleistocene–Holocene transition in W Europe

Based on the evidence of a recently excavated, sealed site, situated at Ruien “Rosalinde” in the Belgian Scheldt valley, the response of hunter-gatherers to changing climate at the transition from the temperate Allerød to the cold Younger Dryas is discussed. Radiocarbon dated to the end of the Allerød or the very beginning of the Younger Dryas, the site of Ruien provides the earliest evidence of a refined lithic technology characterized by the use of a soft stone hammer and the production of straight and regular blade(let)s from intensively prepared cores with two opposite platforms and sharp striking angles. In the course of the Younger Dryas and Early Pre-boreal this knapping method will become standard all over Europe, from the Tanged Point Technocomplex in the North to the (Epi)Laborian in the South. It contrasts sharply with the knapping style of previous lithic traditions, such as the late Federmesser/Azilian and Bromme Technocomplexes, which was much less elaborated and mainly oriented towards the knapping of short irregular blades with a hard stone hammer. This apparently abrupt technological change was also accompanied by increased raw material procurement networks, extending over up to 250 km, and a marked microlithisation of the hunting equipment. Finally, the site of Ruien is also important as it demonstrates the limited archaeological visibility of Younger Dryas sites, explaining the scarcity of such sites within western Europe.

Diamond-Bead Wire Classification and Spectrum with POS Part I: Classification with Process and Object

As a new kind of cutting and grinding tool, diamond-bead wire has gained multi-patterns and many applications. It is commonly comprised of six elements pertaining to corresponding roles for the capacity of the wire: wire rope, diamond bead, clip, spacer, joint, spring or plastic/rubber. For further systematic understanding of diamond-bead wires, researching and developing new bead wires,and making full use of bead wires, it is desperately needed to properly classify diamond-bead wires available and those that may exist in theory. The current study collected and analyzed systematically a hundred of patterns of diamond-bead wires from the diamond-bead wire manufacturers throughout the globe went insight into the essential elements of the wire, including the overall layout, shape characteristics, technological processes, cutting and grinding object, and studied in classification for the spectrum characteristics. And the structural feature covers skeleton package, spacing washer, and special structure; manufacturing process contains bead manufacturing methods and the wire producing processes; and sawing object includes the soft stone, hard stone, and other substances. A trial spectrum has been drawn on the POS classification. All the subjects were discussed and presented in two parts, and here is the first part for classification with processes and objects.

Distribution of Stress on Stone Column-Reinforced Soft Soil under Cylindrical Storage Tank

Structures with circular foundation (chimney, silo, oil tank) constructed on compressible soft soil, often have to opt for ground improvement like stone columns before construction. In this paper, the stress distribution on stone column-reinforced ground under cylindrical storage tank has been presented. Actual foundation soil reinforced with stone column is assumed as composite ground of soil and hollow cylindrical stone rings keeping the area ratio constant to carry the analysis in axi-symmetric condition. The soft soil, stone columns and granular fill are idealized using mechanical elements. The floor slab of the storage tank is assumed to be flexible enough to satisfy the theory of thin plate. Governing differential equations are derived to determine the vertical settlement and solved with finite difference technique. Contact stress at ground level is calculated from vertical settlement. It is observed that soft soil experiences heavy settlement and contact stress when the tank is full despite of low spacing to diameter ratio (S/dc = 3) and reasonable modular ratio (Ec/Es = 20). It is also observed that stress acting on edge stone column is lower as compared to the stress acting on center stone column even under uniformly loaded condition.

In VitroEvaluation of LithAssist: A Novel Combined Holmium Laser and Suction Device

The aim of this in vitro study was to evaluate and compare a novel intracorporeal lithotripter, LithAssist (LA; Cook Medical, Bloomington, IN), with the Swiss LithoClast Ultra (SLU; Boston Scientific, Boston, MA) for the fragmentation and removal of artificial stones made of gypsum-based cement. Ten soft and 20 hard ultracal-30 (U-30) stones were fragmented using two lithotripters. We recorded the stone weight (grams) prior to placing them into a 60-mL syringe for fragmentation. We inserted a 30F percutaneous access sheath into the syringe and positioned the stone within its lumen. Next, we inserted the lithotripter into a right-angled nephroscope. We recorded the times required for first and complete stone disintegration, disintegration to 2 mm, and complete stone removal for each device. In addition, we recorded the stone mass following each minute of stone fragmentation. In total, we subjected 5 soft and 10 hard stones to SLU and LA, respectively. All soft stones were completely disintegrated and removed with both the SLU and LA device. For soft stones, disintegration to 2 mm (2.83±0.41 vs. 4.15±0.70 minutes, p=0.049), complete disintegration (3.18±0.20 vs. 6.40±1.95 minutes, p=0.038), and complete removal (3.30±0.22 vs. 8.82±1.05 minutes, p=0.001) were faster for the SLU compared with the LA. For hard stones, fragmentation was not accomplished with the SLU, whereas with the LA, mean time for first disintegration, disintegration to 2 mm, complete disintegration, and complete removal was 3.60±1.36, 7.25±3.33, 7.54±2.94, and 8.64±2.78 minutes, respectively. In this in vitro study, the SLU was more efficient for softer artificial stones, and the LA was more efficient for harder artificial stones.

Their lips are sealed: identifying hard stone, soft stone, and antler hammer direct percussion in Palaeolithic prismatic blade production

The present experiment examined the differentiation between hard stone, soft stone, and antler hammer in Upper Palaeolithic direct percussion, prismatic blade production through the experimental knapping by two knappers who were asked to produce a series of medium-sized blades. The use of two knappers in the experiment tested knapper variability in the resultant experimental assemblage. While the majority of the attributes of blades and proximal fragments – including the presence of lipping, platform preparation, bulb presence and prominence, and curvature amongst others – did not vary significantly in regards to which hammer type either knapper used, a number of blade attributes differed, significantly yet weakly, and there was almost no direct correlation between the individual knappers blades and the hammer type they used. This suggests strongly that for a given goal of producing medium-sized blades, this can be accomplished equally well using antler, hard stone, or soft stone hammers, and the resultant blades will be difficult to tell apart. Therefore, based on the results of this series of knapping experiments, we would be hesitant in using the 21 variables tested here to differentiate between blades produced with antler, hard stone, and soft stone hammer types in the archaeological record.

Investigation of Differences Between Nanosecond Electropulse and Electrohydraulic Methods of Lithotripsy: A ComparativeIn VitroStudy of Efficacy

To compare the effectiveness of novel nanosecond electropulse lithotripsy with standard electrohydraulic lithotripsy to demonstrate and authenticate their differences because both modalities appear to be similar. An in vitro fragmentation study was conducted using cuboid BegoStone phantoms, which mimic hard and soft stones, based on an established model. Three different stone sizes were used in the testing having volumes of 100, 256, and 320 mm(3). A nanosecond electropulse lithotripter (NEPL) and an electrohydraulic lithotripter (EHL) were operated using a range of probe sizes at comparable energy settings and pulse rates with the objective of obtaining a stone fragment <2 mm. To compare the efficacy of these two lithotripters, the number of pulses needed for stone phantom fragmentation was recorded according to probe size and energy setting, which were then converted into units of cumulative energy. The results clearly demonstrated that, for all operating modes and stone phantom types, the NEPL device needs much less cumulative energy and thus fewer pulses and consequently less time to achieve stone fragmentation than the EHL device. The disparity in the results is explained by the dissimilar mechanisms at work in the compared lithotripters during destruction of the stone. The electropulse stone disintegration mechanism transfers energy directly into the stone because of discharge penetration into a solid body. This contrasts with the electrohydraulic mechanism in EHL in which energy is transferred through the liquid medium, which also creates a damaging shockwave. The findings demonstrate that, for all operating modes and stone types, the NEPL device needs much less cumulative energy and thus fewer pulses for stone fragmentation than the EHL device. The disparity in the results is explained by the dissimilar mechanisms at work in the compared lithotripters during destruction of the stone.

Investigation into fundamental properties of bituminous plug expansion joint filling mixtures containing rubber granules

This paper aims to investigate the fundamental properties of bituminous plug expansion joint filling mixtures containing high content of rubber granules. Rubber granules were added by replacement of part of stone aggregates. Dynamic response, creep, relaxation and flexibility tests were carried out. The test results showed that the addition of rubber granules allowed preparing low modulus joint filling materials. Rubber granules had a great influence on complex modulus, but a limited effect on phase angle. The modified Huet–Sayegh (HS) model was well capable to simulate the rheological properties in a wide range of frequency and temperature. Permanent deformation resistance of joint mixtures was susceptible to the large amount of rubber granules. The slope of relaxation modulus over time on a log–log scale can be used as a reliable indicator to evaluate the relaxation behavior. The replacement of stone aggregates by rubber granules formed a new and soft stone–rubber skeleton, which allowed preparing joint mixtures with a better flexibility at low temperature.