Stone Specimens Research Articles

Ozone-loaded bacterial cellulose hydrogel: a sustainable antimicrobial solution for stone cleaning

The use of biocide-loaded hydrogels has recently been exploited for cleaning the biological attacks of cultural heritage and architectural stone materials. However, considering the drawbacks of traditional biocides, and the high costs of synthetic polymers, growing research for innovative and sustainable solutions are taking place. The aim of this work is to explore a bacterial cellulose (BC) hydrogel functionalized with ozone as a renewable, biodegradable, and easy-to-use antimicrobial remedy for stone biodeterioration. The BC microstructure was characterized by Field Emission-Scanning Electron Microscopy observation and high crystallinity was detected by X-ray diffraction analysis. Ozonated BC (OBC) hydrogels were tested against selected biodeteriogenic microorganisms in water suspension abolishing their viability, with its complete suppression after a 10-min and a 24-h treatment with OBC, for bacterial and fungal spores, respectively. Furthermore, the OBC was assessed on contaminated marble, brick, and biocalcarenitic stone specimens for simulating in situ conditions. A 100% reduction of microbial viability after a 24-h treatment was obtained. Successively, the shelf-life of the hydrogel and the antimicrobial activity were also evaluated after 30 days, demonstrating a subsequent cleaning efficiency along time. This research highlights the potential of the new ozonated BC hydrogel as a green and highly effective antimicrobial treatment, with advantages in sustainability.

The Application of Next-Generation Sequencing in Preoperative Evaluation for Urologic Stone Surgery.

Introduction: Next-generation sequencing (NGS) is a new molecular technique for identifying microorganisms. Treating bacteriuria in patients undergoing stone removal procedures is important for preventing postoperative urinary tract infection (UTI). The objective of this study is to assess the usefulness of preoperative urine NGS testing by comparing NGS with standard urine culture in predicting postoperative UTI after ureteroscopic lithotripsy (URSL) and percutaneous nephrolithotomy (PCNL). Materials and Methods: This prospective study was conducted from February 16, 2022, to January 11, 2024. Sixty subjects who underwent URSL or PCNL were included. Preoperative voided urine samples were collected for urine culture and tested by MicroGenDX for urine polymerase chain reaction (PCR) and urine NGS. Stone specimens obtained intraoperatively were also sent for stone culture and MicrogenDx. Patients were monitored for 4 weeks post-operation for recording clinical outcomes related to infections and complications. Results: Twenty-six (43.3%) male and 34 (56.7%) female participants were included. Twenty-six (43.3%) patients underwent PCNL (15 standard PCNL and 11 mini PCNL), and 34 (56.7%) underwent URSL. Standard urine culture identified positive results in 26 cases (43.3%), PCR for 17 cases (28.3%), and NGS for 31 cases (51.7%). The overall postoperative UTI rate was 6 (10%). Standard urine culture demonstrated a sensitivity of 50%, specificity of 57.4%, and accuracy of 56.7%. Positive predictive value (PPV) was notably poor at 11.5%. Urine NGS showed a higher sensitivity of 83.3%, specificity of 53.7%, accuracy of 55%, and PPV of 16.7%. Conclusion: Urine NGS significantly improves the sensitivity of detecting microorganisms in preoperative urine compared with standard urine culture. Despite its high sensitivity and capability to identify nonculturable bacteria, using NGS alongside standard urine culture is recommended. This parallel approach harnesses the strengths of both methods. Integrating NGS into standard practice could elevate the quality of care, especially for patients at high risk of UTIs, such as those undergoing invasive stone removal procedures.

Strength characteristics and energy evolution of cement stone under true-triaxial loading conditions

Oil well cement is a commonly used cementing material in oil and gas extraction engineering. Due to the change of stress conditions, it is prone to microcracks or micro annular gaps, leading safety concerns. To study the strength characteristics and energy evolution of oil well cement stone under three-dimensional stress states, a series of true-triaxial compression tests were carried out. Based on the experimental results, the mechanical properties and energy evolution mechanisms during the true-triaxial compression process of cement stone under different stress states were explored. The research results indicate that there is an intermediate principal stress effect on the true-triaxial compressive strength of cement stone specimens. When the minimum principal stress remains constant, the strength of cement stone first increases and then decreases with the increase of intermediate principal stress. When the minimum principal stress is 5 MPa, the specimen exhibits brittle failure, with ε1 at peak stress approximately 0.015. As the minimum principal stress increases to 20 MPa, the specimen gradually transits to plastic failure, with ε1 at failure exceeding 0.04. The type of failure is determined by the energy ratio at the time of failure; when there is more elastic energy, it results in brittle failure, otherwise it leads to ductile failure. Due to the high porosity of cement stone samples, most of the input energy is converted into dissipated energy. At minimum principal stresses of 5 MPa, 10 MPa and 20 MPa, the ratio of peak dissipated energy to total input energy fluctuates around 0.55, 0.73 and 0.85, respectively. There is a strong linear relationship between the peak elastic energy, peak dissipated energy, and total input energy, with fitting correlation coefficients of 0.847 and 0.996, indicating that the cement stone sample also follows the linear energy storage law. A strength criterion for cement stone was established based on the modified Lade criterion, which is more suitable for describing the strength of high porosity materials compared to traditional strength criteria. Finally, based on the interaction mechanism between energy accumulation and energy dissipation, a nonlinear model of energy evolution in cement stone was established. The results of the theoretical model are in good agreement with the experimental data.

A four-grating interferometer for x-ray multi-contrast imaging.

X-ray multi-contrast imaging with gratings provides a practical method to detect differential phase and dark-field contrast images in addition to the x-ray absorption image traditionally obtained in laboratory or hospital environments. Systems have been developed for preclinical applications in areas including breast imaging, lung imaging, rheumatoid arthritis hand imaging and kidney stone imaging. Prevailing x-ray interferometers for multi-contrast imaging include Talbot-Lau interferometers and universal moiré effect-based phase-grating interferometers. Talbot-Lau interferometers suffer from conflict between high interferometer sensitivity and large field of view (FOV) of the object being imaged. A small period analyzer grating is necessary to simultaneously achieve high sensitivity and large FOV within a compact imaging system but is technically challenging to produce for high x-ray energies. Phase-grating interferometers suffer from an intrinsic fringe period ranging from a few micrometers to several hundred micrometers that can hardly be resolved by large area flat panel x-ray detectors. The purpose of this work is to introduce a four-grating x-ray interferometer that simultaneously allows high sensitivity and large FOV, without the need for a small period analyzer grating. The four-grating interferometer consists of a source grating placed downstream of and close to the x-ray source, a pair of phase gratings separated by a fixed distance placed downstream of the source grating, and an analyzer grating placed upstream of and close to the x-ray detector. The object to be imaged is placed upstream of and close to the phase-grating pair. The distance between the source grating and the phase-grating pair is designed to be far larger than that between the phase-grating pair and the analyzer grating to promote simultaneously high sensitivity and large FOV. The method was evaluated by constructing a four-grating interferometer with an 8µm period source grating, a pair of phase gratings of 2.4µm period, and an 8µm period analyzer grating. The fringe visibility of the four-grating interferometer was measured to be ≈24% at 40kV and ≈18% at 50kV x-ray tube operating voltage. A quartz bead of 6mm diameter was imaged to compare the theoretical and experimental phase contrast signal with good agreement. Kidney stone specimens were imaged to demonstrate the potential of such a system for classification of kidney stones. The proposed four-grating interferometer geometry enables a compact x-ray multi-contrast imaging system with simultaneously high sensitivity and large FOV. Relaxation of the requirement for a small period analyzer grating makes it particularly suitable for high x-ray energy applications such as abdomen and chest imaging.

Composition analysis of renal and ureteral calculi in a single center in northern China in the past decade.

The current report aimed to evaluate the characteristics of stone composition in 3637 renal and ureteral calculi patients in a single center while clarifying its relationship with sex, age, and time. Out of 3637 cases of upper urinary tract stones, stone specimens were analyzed retrospectively. There were 2373 male patients aged 6 months-87 years, with an average age of 44.73 ± 15.63 years, and 1264 female patients aged 4 months-87 years, with an average age of 46.84 ± 16.00 years. The male-female ratio was 1.88:1. Five hundred twelve patients had ureteral calculi, and 3125 had renal calculi. The SPSS software helped analyze the relationship between renal and ureteral calculi composition and sex, age, and time. Stone composition demonstrated 2205 cases of calcium oxalate stones (60.6%), 518 carbonate apatite (14.2%), 386 uric acids (10.6%), 232 magnesium ammonium phosphate (6.4%), 117 calcium phosphate (3.2%), 76 cystine (2.1%), 47 sodium urate (1.3%), 31 others (0.9%), and 25 ammonium urate (0.7%) cases. The overall male-to-female sex ratio was 1.88:1. Stones in the upper urinary tract were significantly more frequent in men than in women between the ages of 31 and 60. However, such stones were significantly more frequent in women than men over 80 (P < .05). Cystine, Sodium urate, Carbonated apatite, and uric acid indicated significant differences between different age categories (all P < .001). Stone composition analyses revealed that the frequency of calcium oxalate calculi has increased annually, while cystine and carbonated apatite incidences have dropped annually over the past decade. The components of renal and ureteral calculi vary significantly based on age and sex, with calcium oxalate calculi being more frequent in men while magnesium ammonium phosphate stones are more frequent in female patients. The age between 31 and 60 years is the most prevalent for renal and ureteral calculi in men and women.

Natural Deep Eutectic Solvents as Rust Removal Agents from Lithic and Cellulosic Substrates.

The peculiar physicochemical features of deep eutectic solvents (DESs), in particular their tunability, make them ideal media for various applications. Despite their ability to solubilize metal oxides, their use as rust removers from valuable substrates has not yet been thoroughly investigated. In this study, we chose three known DESs, consisting of choline chloride and acetic, oxalic or citric acid for evaluating their ability to remove corrosion products from a cellulose-based material as linen fabric and two different lithotypes, as travertine and granite. The artificial staining was achieved by placing a rusty iron grid on their surfaces. The DESs were applied by means of cellulose poultice on the linen fabrics, while on the rusted stone surfaces with a cotton swab. Macro- and microscopic observations, colorimetry and SEM/EDS analysis were employed to ascertain the cleaning effectiveness and the absence of side effects on the samples after treatment. Oxalic acid-based DES was capable of removing rust stains from both stone and cellulose-based samples, while choline chloride/citric acid DES was effective only on stone specimens. The results suggest a new practical application of DESs for the elimination of rust from lithic and cellulosic substrates of precious and artistic value.

Evaluation of the Yttrium Oxide Effect on Some Mechanical Properties of (Type III) Dental Stone

For many years, gypsum compounds have been used in dentistry. They're used to make casts for various dental laboratory operations. Gypsum products have important characteristics such as "quality, abrasion resistance, compressive strength, hardness, linear setting expansion during setting, and detail replication". Additionally, the use of additives such as gum arabic, ferric oxide, calcium oxide, and calcium carbonate has greatly improved the compressive strength of gypsum products. The purpose of this study was to investigate the effects of yttrium oxide (Y2O3) addition on the hardness and compressive strength of dental stones. Thirty dental stone specimens of (type III) were prepared and separated into (3) groups: group (A) control group, no additives, group (B) 3% Y2O3, and group (C) 5% Y2O3. The control and experimental groups' mechanical parameters (surface hardness and compressive strength) were measured, and a Shore D hardness tester was used to indent the specimens. An electronic universal testing apparatus with computer control was used to conduct the compressive strength test. The Tukey-HSD test found no difference in surface hardness between the control and experimental groups, a non-significant difference in compressive strength between the control group and dental stone +3% Y2O3, and a significant difference in compressive strength between the control group and dental stone +5% Y2O3. Between dental stones with 3% and 5% Y2O3, there was a substantial difference in compressive strength. The addition of yttrium oxide at weight ratios of 3% and 5% to dental stone did not affect the surface hardness. The addition of 5% yttrium oxide decreased the compressive strengths.

Structure and properties of modified shungite concrete during electrode heating

Concrete composition modifying by different electrically conductive components is one of less laborious but relatively effective methods between wide variety of electrode concrete heating effectiveness improvement methods. The purpose of this study is investigation of special aspects of cement systems modified by powdered shungite (Ssp 400 m2/kg) in combination with active mineral and plasticizing admixtures that harden under electrode heating at below zero temperatures. By the method of differential thermal analysis anomaly of exothermic reaction of cement stone specimens was discovered, that is due to formation of hydrated calcium silicate С2SH (A) discovered by the method of quantitative XRDA, and is verified by results received from scanning electron microscopy method, which among other factors provides higher strength and low permeability to these composites. Stability of cement systems modified by shungite and curing under electrode heating has been proved.

Application of slags for the production of resource‐efficient paving stones

AbstractIn a recent research project under the lead of the Fraunhofer Institute for Building Physics IBP, gravel and sand within a mixture of paving stones were replaced with LD converter slag and blast furnace slag for 50 wt. % and 100 wt. % to produce resource‐efficient concrete components. For this purpose, first, the dry processing of the slags including metal separation and crushing was carried out. In the next step, the particle size distributions of slags using sieve analysis were determined. Finally, the mix designs were set based on the optimum combination of different size fractions of slags. This combination was determined in a way to lead to an almost identical grading curve as that of the original formulation. Splitting tensile strengths of the obtained samples were measured after 14 days of curing under a humidity of 95%. Several paving stone specimens containing slags showed higher splitting tensile strengths than that of the reference sample. Similar results were observed for industrially produced paving stones which demonstrates the successful transfer of the laboratory mixes to the industrial plant.

New Triple Metallic Carbonated Hydroxyapatite for Stone Surface Preservation

This paper presents the synthesis of the triple substituted carbonated hydroxyapatite with magnesium, strontium and zinc (Mg-Sr-Zn-CHAp), as well as its structural, morphological and compositional characterization. The analytical techniques used (WDXRF, XRD and FTIR) highlighted, on the one hand, the B form for the apatite structure, as well as the presence of the three metal ions in the apatite structure, on the other hand (small shifts of 1120–900 cm−1 and 500–600 cm−1 absorption peaks due to the metals incorporated into the CHAp structure). The ratio between the metallic ions that substitute calcium and Ca2+, and phosphorus is increased, the value being 2.11 in comparison with CHAp and pure hydroxyapatite. Also, by using imaging techniques such as optical microscopy and SEM, spherical nanometric particles (between 150 and 250 nm) with a large surface area and large pores (6 m2/g surface area, pores with 6.903 nm diameters and 0.01035 cm3/g medium volume, determined by nitrogen adsorption/desorption analysis) and a pronounced tendency of agglomeration was highlighted. Also, the triple substituted carbonated hydroxyapatite was tested as an inorganic consolidant by using stone specimens prepared in the laboratory. The efficiency of Mg-Sr-Zn-CHAp in the consolidation processes was demonstrated by specific tests in the field: water absorption, peeling, freeze–thaw behavior, chromatic parameters as well as mechanical strength. All these tests presented conclusive values for the use of this consolidant in the consolidation procedures of stone surfaces (lower water absorption, increased mechanical strength, higher consolidation percent, decreased degradation rate by freeze–thaw, no significant color changes).

Quaternary ammonium silane modified Nanolime for the consolidation and antifungal of stone relics

Cultural relics such as wall paintings and stone relics face a decrease in mechanical strength and contamination from microbial growth. Nanolime (NL), as an exceptional inorganic nanomaterial used in the consolidation of cultural heritages, has been investigated for more than two decades. However, it has limited antibacterial properties. Here, we opted for dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (DC5700) to modify the surface of NL particles, praparing an organic–inorganic hybrid nanomaterial (NL-DC5700) that provides long-lasting antifungal effects for stone samples without sacrificing its consolidation effect. Characterizations demonstrate that DC5700 grafts onto the surface of NL particles through the formation of covalent bonds via dehydration condensation between the siloxane of DC5700 and the hydroxyl of NL, forming an organic shell layer that uniformly wraps the NL particles. NL-DC5700 can endow stone samples with near superhydrophobicity (NL, 25.4° and NL-DC5700, 142.0°) and durable antifungal effects over 90 days, superior to those of pure NL. NL-DC5700 shows no unacceptable impact on the appearance, porosity, or microstructure of the stone specimens. Our work explores the antifungal effect of NL-based materials and provides fresh insights into the development of versatile conservation materials for stone relics.

Consolidating Efficiency of Nanolime Product CaLoSiL on Porous Limestone

The effects of the double and the multiple application (2 to 6) of Calosil® (IBZ-Salzchemie GmbH, Halsbruecke, Germany) E25, IP 25 and E50 products were studied on Maastricht limestone, which is characterized by high porosity and large pores. Both destructive and non-destructive laboratory tests we performed in order to assess the consolidating efficiency of the nanolimes—the bending and compressive strengths, ultrasound velocity measurement, porosity determination and SEM examination. Except for the compressive strength, the other characteristics were investigated in the depth profile of stone specimens to find the distribution of the treatment product within the substrate. The performed tests showed good penetration of CaLoSiL nanolime products into the studied limestone. The bending strengths of limestone samples after double treatment using nanolime E 25, IP25 and E 50 were found to be increased by 50%, 44% and 89%, respectively, whereas the compressive strength increased by 50%, 23% and 73%. The porosity of the stone was reduced by the treatment, but only slightly, to an acceptable extent. The higher sum of performed nanolime applications resulted in a higher strengthening effect but at the same time at the uneven distribution of the product in the stone specimen, which was followed by an increase in the strength and decrease of open porosity in the surface part. SEM examination showed a modification of the stone microstructure by the added binder.

Evaluation of CBR of Graded Crushed Stone of Flexible Base Structural Layer Based on Discrete Element Model

In order to study the mechanical properties of graded crushed stone, the discrete element method is used to simulate the CBR test of graded crushed stone. Aiming at the composition structure of graded crushed stone material, the PFC3D simulation software is used to construct the test model, and the process of constructing the virtual specimen model of the graded crushed stone discrete element model is discussed in detail. A servo mechanism is used to control the speed of the wall in the software, so as to control the virtual confining pressure imposed on graded crushed stone by the wall and simulate the real CBR test environment. The micro-parameter calibration of the virtual test is carried out by comparing the indoor and virtual CBR specimens of a single particle size specimen and three groups of graded crushed stone specimens. The comparison result shows that the stress-strain characteristics of the graded crushed rock obtained by the discrete element simulation during the uniaxial penetration process have a high degree of similarity, which can verify the accuracy of the model establishment. With the increase in the penetration depth, the penetration force of the aggregates of various particle sizes gradually increases, and the penetration force and the penetration depth are basically linear, and when the particle size is greater than 9.5 mm, the increase in particle size has little effect on the CBR test results. Under the certain conditions, the contact stiffness of graded crushed stone particles with particle sizes of 4.75 mm, 9.5 mm, 13.2 mm, 16 mm, and 19 mm should be 0.88 × 107 (N/m), 0.98 × 107 (N/m), 1.10 × 107 (N/m), 1.25 × 107 (N/m), and 2.05 × 107 (N/m), respectively. The recommended value of the contact stiffness of the small spherical particles increases with the increase in the particle size. This model can provide a basis for studying the micromechanical state of graded crushed stone and physical mechanics tests.

Experimental study on physical properties of superfine cement grouting material

In this paper, the properties of superfine cement with different mesh sizes are observed from both macro and micro perspectives through laboratory tests, and the fluidity, stability, and mechanical properties of superfine cement are studied in depth. The results show that increasing the mesh size of superfine cement can reduce the influence of the water-cement ratio on slurry, reduce the fluidity of superfine cement, and enhance its stability. The strength of the superfine cement stone specimen will increase with the increase in cement mesh number, and the higher the mesh number, the shorter the time required for the superfine cement stone specimen to reach its maximum strength. Considering the performance, cost, and storage difficulty, the superfine cement with the mesh size of K700 is more cost-effective. Using K700 superfine cement grout can effectively reduce the impact of geostress on the surrounding rock of the roadway and inhibit the deformation and damage of the surrounding rock.

Silver-Doped TiO2-PDMS Nanocomposite as a Possible Coating for the Preservation of Serena Stone: Searching for Optimal Application Conditions

The main objective of this research is to determine the optimal application conditions of a newly synthesized multifunctional coating containing Ag-doped TiO2 nanoparticles when used as a possible protective agent for sandstone. Firstly, Ag-TiO2 nanoparticles with anatase structure, spherical shape and controllable sizes were prepared using the sol–gel method and characterized. The biocidal activity of Ag-doped TiO2 NPs was studied by comparing its performance to pure TiO2 NPs against two representative Gram-positive and Gram-negative bacterial strains, under both visible irradiation and in the dark; then, the antimicrobial efficiency of two different concentrations of Ag-TiO2 nanoparticles (0.1–1 mol%) was evaluated against two phototrophic strains commonly isolated from deteriorated surfaces. Results showed that the photoactivation and photokilling activity of TiO2 were highly improved by doping with Ag. Next, prepared nanopowders were dispersed in a binder with different powder/PDMS ratios: (0.1, 0.2, 0.5 and 1% w/v TiO2) and then applied in different amounts (2, 3 and 6 g/m2) on Serena stone specimens. Results revealed that the application of 2 g/m2 nanocomposite at powder/binder ratios equal to 1% w/v TiO2 provided a fine hydrophobic character for the stone material with acceptable chromatic variations.

Evaluation of Ordering Practices, Microbial Yield, and Clinical Utility of Urinary Stone Cultures

Abstract Urinary stones are a global problem. While it has been established that microorganisms can be associated with urinary stone formation, data on best practices for microbial culture and clinical interpretation of microbial culture of urinary stone specimens are limited. Our objective was to investigate the microorganisms present in urinary stone cultures (usc) and companion urine cultures. We conducted a retrospective study at a tertiry hospital examining cultures submitted between October 2018 and October 2021. We collected data from electronic medical records of patients who had at least at least one usc performed. As part of routine clinical workup, all urinary stone specimens submitted for culture were ground using a disposable tissue grinder and inoculated on a tryptic soy agar with 5% sheep blood agar plate (BAP), a chocolate agar plate (CHOC), and a MacConkey agar plate (MAC), streaked for isolation and incubated in 5% CO2 at 35°C for up to three days. Urine cultures were performed using the Kiestra TLA system with 10 µL of inoculum onto each of a BAP and MAC, and plates were examined at 16 and 24 hours of incubation. For urine specimens submitted from a straight or “in and out” catheter, 10,000 CFU/mL was the threshold for workup. From clean-voided, midstream, ileostomy, nephrostomy, or indwelling/Foley catheter specimens, 100,000 CFU/mL was the threshold for workup. The final clinical significance of cultures is determined by evaluating the culture result in light of the patient’s clinical presentation. For usc and urine cultures, clinically insignificant growth was considered no growth or when no pathogens were recovered in culture. Urine cultures with more than 3 species over threshold were considered contaminated. A total of 1,049 usc were performed from 854 patients (55.3% female). The median patient age was 61 years (IQR 49-70). The most frequent microorganisms reported in usc cultures were Proteus mirabilis (N=98), Enterococcus faecalis (N=75), and Escherichia coli (N=73). No pathogen was identified from 57% of usc. 441 usc were performed in a context of urine culture (+/-2 days) in 336 (39.3%) patients. In addition, 138 patients (16.1%) had more than 1 usc, being the maximum as 11 usc performed in one patient. The most common urine/USC concordant result was no growth in 165 of 441 cultures (37.4%), followed by coagulase negative Staphylococcus. Cohen’s kappa obtained from usc and urine culture results was 0.45, which is not the minimum acceptable agreement. A pathogen was identified from usc in 43% of cases. Usc and urine cultures rarely resulted in concordant results, but the most common concordant result was no growth in culture. Additional studies are warranted to evaluate the impact of usc results on patient care, including antimicrobial use and correlation of microbes isolated with stone chemical composition.

Using micro computed tomographic imaging for analyzing kidney stones.

Stone analysis is a critical part of the clinical characterization of urolithiasis. This article reviews the strengths and limitations of micro CT in the analysis of stones. Using micro CT alone in a series of 757 stone specimens, micro CT identified the 458 majority calcium oxalate specimens with a sensitivity of 99.6% and specificity of 95.3%. Micro CT alone was also successful in identifying majority apatite, brushite, uric acid, and struvite stones. For some minor minerals-such as apatite in calcium oxalate or calcium salts in uric acid stones-micro CT enables the detection of minute quantities well below 1%. The addition of a standard for calibrating X-ray attenuation values improves the ability of micro CT to identify common stone minerals. The three-dimensional nature of micro CT also allows for the visualization of surface features in stones, which is valuable for the study of stone formation.

Effect of calcination pretreatment on mechanical properties of alkali-activated artificial stone incorporating Yellow River silt

The resource utilization of the Yellow River silt is one of the key issues for the protection and management of the Yellow River in China. One of the effective methods for this goal is to prepare artificial stones using the Yellow River silt as the main raw materials. The purpose of this study is to explore the effect of calcination pretreatment on the mechanical properties of artificial stone incorporating Yellow River silt. The artificial stone was fabricated via the alkali-activation and pressure-forming method. The compressive strength and splitting tensile strength of fabricated artificial stone specimens with different alkali dosages, fly ash contents and curing ages were measured. The microstructures of alkali-activated artificial stone specimens were observed by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectrum (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The results show that the mechanical properties of the artificial stone incorporating Yellow River silt can be improved obviously by calcination pretreatment. Moreover, it can be found that alkali dosages, fly ash contents and curing ages play important roles in the level of improvement on the mechanical properties. The highest compressive strength of the artificial stones at 90 days is 16.6 MPa, and the corresponding splitting tensile strength is 1.4 MPa. The main reason for the increase of strength is that calcination pretreatment facilitates the production of alkali-activated products, that is, hydration calcium silicate (C–S–H) gels. These results suggest the possibility of using calcinated Yellow River silt as reliable and economical building materials in a wide range of construction engineering applications, especially in river slope protection, flood control and other projects.

PD50-07 DEFINING STONE PASSAGE IN A CLINICAL TRIAL: ADJUDICATION IN THE PREVENTION OF URINARY STONES WITH HYDRATION (PUSH) STUDY

You have accessJournal of UrologyCME1 May 2022PD50-07 DEFINING STONE PASSAGE IN A CLINICAL TRIAL: ADJUDICATION IN THE PREVENTION OF URINARY STONES WITH HYDRATION (PUSH) STUDY Hunter Wessells, Henry Lai, John Lieske, Brian Matlaga, Sharon Settles, Hongqiu Yang, Jonathan Harper, Charles Scales, Alana Desai, Naim Maalouf, Peter Reese, Sri Sivalingam, Gregory Tasian, Hussein Al-Khalidi, and Ziya Kirkali Hunter WessellsHunter Wessells More articles by this author , Henry LaiHenry Lai More articles by this author , John LieskeJohn Lieske More articles by this author , Brian MatlagaBrian Matlaga More articles by this author , Sharon SettlesSharon Settles More articles by this author , Hongqiu YangHongqiu Yang More articles by this author , Jonathan HarperJonathan Harper More articles by this author , Charles ScalesCharles Scales More articles by this author , Alana DesaiAlana Desai More articles by this author , Naim MaaloufNaim Maalouf More articles by this author , Peter ReesePeter Reese More articles by this author , Sri SivalingamSri Sivalingam More articles by this author , Gregory TasianGregory Tasian More articles by this author , Hussein Al-KhalidiHussein Al-Khalidi More articles by this author , and Ziya KirkaliZiya Kirkali More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002621.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Clinical trials in patients with urinary stone disease have used variable definitions of stone events/ passage. We assessed the accuracy of self-reported stone passage in a large clinical trial using a blinded adjudication process. METHODS: Study participants (n=1642) in the two arm PUSH trial are randomized either to a behavioral intervention or control arm to increase and maintain high fluid intake. The primary endpoint is symptomatic kidney stone recurrence including stone passage observed and/or captured by the participant or procedural intervention for stones. Adjudication of the primary endpoint (Confirmed Event) requires corroboration via photograph, stone specimen, imaging, definitive record of symptoms (pain, nausea/vomiting, urinary symptoms, hematuria) and passage and/or surgical intervention in clinical notes. A Suspected Stone Event (SSE) category was created for participants with symptoms and passage without complete documentation. RESULTS: At time of this analysis 1532 participants were randomized with a median of 692 days of follow-up. Self-reported stone passage (n=185) was adjudicated by an independent committee as confirmed in 114 (61.6%), SSE in 61 (33%), and non-events in 10 (5.4%). The overall Kaplan Meier rate of confirmed plus suspected events at 1 year was 9.1% (95% CI 7.7-10.8). The rates of adjudicated stone passage varied across the duration of the study (Figure). CONCLUSIONS: In the PUSH trial rigorous blinded adjudication revealed that self-reported stone passage overwhelmingly represented definitive or likely (SSE) events at all time points up to 2 years. The divergence of the rate of confirmed vs suspected events after one year requires further investigation. The inclusion of SSE and procedural intervention allows for the full burden of stone events to be ascertained. These results will inform endpoint assessment in future urinary stone trials. Source of Funding: NIH/NIDDK © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e838 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Hunter Wessells More articles by this author Henry Lai More articles by this author John Lieske More articles by this author Brian Matlaga More articles by this author Sharon Settles More articles by this author Hongqiu Yang More articles by this author Jonathan Harper More articles by this author Charles Scales More articles by this author Alana Desai More articles by this author Naim Maalouf More articles by this author Peter Reese More articles by this author Sri Sivalingam More articles by this author Gregory Tasian More articles by this author Hussein Al-Khalidi More articles by this author Ziya Kirkali More articles by this author Expand All Advertisement PDF DownloadLoading ...

PD32-10 KIDNEY STONE ENDOTOXIN CONCENTRATION CORRELATES WITH POST-OPERATIVE SEPSIS FOLLOWING PERCUTANEOUS NEPHROLITHOTOMY

You have accessJournal of UrologyCME1 May 2022PD32-10 KIDNEY STONE ENDOTOXIN CONCENTRATION CORRELATES WITH POST-OPERATIVE SEPSIS FOLLOWING PERCUTANEOUS NEPHROLITHOTOMY David T. Tzou, Farhan Anwar, Ava C. Wong, David T. Harris, Thomas Chi, and Gayatri Vedantam David T. TzouDavid T. Tzou More articles by this author , Farhan AnwarFarhan Anwar More articles by this author , Ava C. WongAva C. Wong More articles by this author , David T. HarrisDavid T. Harris More articles by this author , Thomas ChiThomas Chi More articles by this author , and Gayatri VedantamGayatri Vedantam More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002583.10AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Patients with infected kidney stones are at risk for post-operative sepsis following surgical removal of their calculi. Of all the surgical approaches, percutaneous nephrolithotomy (PCNL) remains associated with the highest risk for experiencing post-operative SIRS (severe inflammatory response syndrome). Accurate prediction of patients at risk for SIRS after surgery would be of clinical value. While previous studies have demonstrated infected kidney stones contain variable levels of endotoxin concentrations, these were limited in their rigor and ability to correlate stone immunobiology with important clinical outcomes. The aim of this study was to quantitate endotoxin levels amongst PCNL patients who experienced and did not experience SIRS. METHODS: Between October 2020 and June 2021, urine & stone specimens from consecutive stone patients were prospectively collected as part of the Registry for Stones of the Kidneys and Ureter (ReSKU) at the University of Arizona. Clinical data including stone analyses and post-operative outcomes have been tracked. Equal weights of stones were uniformly broken using an easy-to-replicate ‘beat-beating’ homogenization approach, allowing for consistent measurement of stone endotoxin using a Pierce™ LAL Chromogenic Endotoxin Quantification Kit (ThermoFisher, Waltham, MA). Endotoxin levels from stones removed during PCNL were compared between patients who experienced and did not experience SIRS. Independent T-test was used to determine statistical significance. RESULTS: Endotoxin levels amongst 4 patients with infection calculi who experienced SIRS were compared to 16 patients who did not experience SIRS – 8 of which had infection calculi and 8 had non-infection calculi (Figure 1). In the SIRS group, the mean Endotoxin concentration was 1.084 endotoxin units (EU)/ml compared to 0.476 EU/ml in the non-SIRS group (p<0.01). CONCLUSIONS: Higher kidney stone bacterial endotoxin concentrations are present in patients who experienced SIRS after percutaneous stone removal compared to those who did not. Whether exceeding a threshold endotoxin level corresponds to patients experiencing SIRS warrants future study. Source of Funding: P30DK081943 – SUBK00015084 - NIH/NIDDK; University of Arizona Health Sciences Career Development Award © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e550 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information David T. Tzou More articles by this author Farhan Anwar More articles by this author Ava C. Wong More articles by this author David T. Harris More articles by this author Thomas Chi More articles by this author Gayatri Vedantam More articles by this author Expand All Advertisement PDF DownloadLoading ...