Struvite Research Articles

Antimicrobial and antiurolithiatic activities of pure and silver doped copper oxide nanoparticles using Moringa Oleifera leaf extract on struvite urinary stones

The development of nanoparticles plays a significant role in contemporary medicament. Struvite stones are associated with urinary tract infection, there are several techniques provided including drug therapy, and extracorporeal shock wave lithotripsy (ESWL) in consequence, the present study was focused onto attain the antiurolithiatic activity of pure and 20% of Ag-doped CuO nanoparticles mediated from Moringa Oleifera leaf extract. The synthesized nanoparticles were characterized using X-ray Diffraction. The Monoclinic structure and the average crystallite size for pure and 20% Ag-doped CuO nanoparticles were found to be 15.22nm and 3.67nm. The surface morphology of the specimens was analyzed by Field-Emission Scanning Electron Microscopy and Transmission Electron Microscopy. FE-SEM images showed nanostructures for pure and 20% Ag-doped CuO nanoparticles. The average particle size obtained for the nanoparticles from FE-SEM was found to be in the range of 12.84 nm-14.52 nm & 2.55 nm-5.04 nm was in good agreement with the average crystallite size from XRD results. TEM images displayed that CuO nanoparticles were distributed uniformly and for 20% Ag-doped CuO nanoparticles, Ag nanoparticles adhered on the surface of CuO nanoparticles. The presence of the synthesized materials was detected by Energy Dispersive X-ray analysis. Functional groups were identified by Fourier Transform Infrared Spectroscopy. From, Zeta Potential analysis, the negative potential value of -34.23 mV and -36.12 mV for green synthesized nanoparticles were identified. The diffraction patterns and functional groups of struvite crystals were confirmed by X-ray diffraction and Fourier Transform Infrared Spectroscopy. The inhibitory effect of synthesized 20% Ag-doped CuO nanoparticles showed a percentage of inhibition of 86.95% as compared with pure CuO showed 81.52% at a 5% concentration. Maximum inhibition was observed for 20% Ag-doped CuO nanoparticles against bacterial pathogens such as S. aureus, Bacillus subtilis, and Escherichia coli (8mm) in diameter and fungal Candida albicans (6mm) in diameter. Therefore the present study revealed that the synthesized pure and 20% Ag-doped CuO Nps mediated from M. Oleifera leaf extract encourage the creation of ammonium magnesium phosphate hexahydrate crystals and reduction in nucleation rate of urinary tract infection causing struvite stones.

Amount and speciation of N leached from a sandy soil fertilized with urea, liquid digestate, struvite and NH4‐enriched chabazite zeolite‐tuff

AbstractThe large use and the bad management of fertilizers that are applied to soil for improving crop production have dramatically impaired soil, water, and air quality. To meet the requirements to reduce nitrogen (N) losses and all the related negative impacts on the environment and food production, it is mandatory to substitute or at least partially substitute the use of inefficient and unsustainable fertilizers with more efficient alternatives. The aim of this paper was to address the amount and speciation of the N released by a sandy soil fertilized with “slow‐release fertilizers” and traditional fertilizers (urea and liquid digestate) by means of a series of column leaching experiments. The slow‐release alternatives were represented by NH4‐enriched zeolitic tuff and struvite, both obtained by recovering the N from liquid digestate. The treatments consisted of sandy soil fertilized with (i) urea (U) (ii) liquid digestate (LD), (iii) NH4‐enriched zeolitic tuff (N‐CHA) and (iv) struvite (STRV). Eight different flushing events were performed over 38 days, leachates were collected and analysed for total Kjeldahl N, organic‐N, NH4+‐N, NO3−‐N, NO2−‐N and pH. U and LD lost the majority of N within the first 2 flushing events as organic N and NH4+‐N, respectively. On the other hand, STRV and N‐CHA lost less N over the whole course of the experiment and with more balanced speciation. The mass balance outlined that after the experiment, native soil N was mined in U and LD treatments while in N‐CHA and STRV a fraction of N from the fertilizers was still present. The results showed a slow release of N which can be used more efficiently in agricultural applications, minimizing the N losses.

Analysis of Urinary Calculi by Fourier Transform Infrared Spectroscopy for Patients in Northern Jordan

The variations in urinary calculi are based on different diameters, which range in the form of sand grain to a urinary collecting system so that it can pass through the urinary tract regardless of any symptoms. To determine the composition of urinary calculi for patients in Northern Jordan by using Fourier Transform Infrared Spectroscopy method, samples of urinary calculi were retrieved from patients at King Abdullah University Hospital and Princess Basma Teaching Hospital. Urinary calculi were surgically removed from patients either arthroscopically (n = 35), or by percutaneous nephrolithotomy (PCNL) (n = 15) over a period of 16 months (2013-2014) and were brought to the laboratory in sterile containers. They were analyzed by Fourier Transform Infrared Spectroscopy method. A total of 39 male patients (78%) aging 23-85 years and 11 female patients (22%) aging 33-69 years were included in the study. The calculi comprised of 40% calcium oxalate and uric acid, 24% calcium oxalate, 18% pure uric acid, 12% magnesium ammonium phosphate, and 6% calcium oxalate and calcium phosphate. Mixed urinary calculi of calcium oxalate and uric acid were predominantly found among the patients with the following characteristic IR bands [1637cm-1 C=C Stretching, 1021 cm-1 N-H stretching, 780 cm-1 aromatic C-N stretching].

An integrated process for struvite recovery and nutrient removal from ship domestic sewage

Marine pollution caused by the untreated and substandard discharge of ship domestic sewage has received widespread attention. A novel integrated process for struvite recovery and nutrient removal from ship domestic sewage (SRNR-SDS) based on seawater magnesium source was developed in this study. Removal efficiencies of the total nitrogen (TN) and total phosphorus (TP) for the activated sludge unit in SRNR-SDS process were approximately 67.61% and 41.35%, respectively, under the salinity of 7.85 g/L. The coupling-induced struvite crystallization unit significantly improved the removal efficiency of TN and TP, and the scanning electron microscopy and X-ray diffraction demonstrated that magnesium ammonium phosphate (MAP) crystals were successfully formed on the surface of zeolite. The SRNR-SDS process had an ideal performance for pollutant removal and MAP recovery under the optimal hydraulic retention time of 20 h. The effluent concentrations of COD, NH4+-N, TN and TP in SRNR-SDS process were approximately 34.73 mg/L, 4.31 mg/L, 10.07 mg/L and 0.23 mg/L, respectively, which meet the Chinese and international ship sewage discharge standards. SRNR-SDS process has obvious environmental, social and economic benefits, which could save 6.20%∼57.14% of the operation cost of ship domestic sewage treatment via MAP recovery. The results could provide theoretical and technical support for the development and application of ship sewage treatment process with the functions of pollutant removal and resource recovery.

1H NMR metabolic profiling of Staphylococcus pseudintermedius isolated from canine uroliths.

Staphylococcus pseudintermedius is a urease-producing bacteria which is a major cause of magnesium ammonium phosphate (MAP) urolithiasis in canine. A positive urolith culture is an important risk factor for MAP urolithiasis in canine. The mechanism underlying the metabolic changes of S. pseudintermedius after crystallization in artificial urine (AU) needs more defined baseline metabolic information. Therefore, we extensively investigated the metabolic changes of S. pseudintermedius extensively after crystallization in AU. A high urease activity and positive biofilm formation strain, entitled the S. pseudintermedius (SPMAP09) strain, was isolated from canine MAP uroliths, and analyzed using nuclear magnetic resonance (NMR) spectroscopy-based metabolomics. The molecular mechanism-specific metabolic phenotypes were clearly observed after crystallization in AU at day 3. The crystals induced by SPMAP09 were also confirmed and the major chemical composition identified as struvite. Interestingly, our findings demonstrated that a total of 11 identified metabolites were significantly changed. The levels of formate, homocarnosine, tyrosine, cis-aconitate, glycolate, ethyl malonate, valine and acetate level were significantly higher, accompanied with decreased levels of inosine, glucose, and threonine at day 3 compared with the initial time-point (day 0). In addition, our results exhibited that the glyoxylate and dicarboxylate metabolism was significantly related to the SPMAP09 strain at day 3 in AU. Thus, metabolic changes of the SPMAP09 strain after crystallization in AU potentially helps to explain the preliminary molecular mechanism for the crystals induced by S. pseudintermedius.

Effect of spherical silica fume and fly ash on the rheological property, fluidity, setting time, compressive strength, water resistance and drying shrinkage of magnesium ammonium phosphate cement

Due to the high bonding strength, Magnesium ammonium phosphate cement (MAPC) is suitable for the crack repair. However, the fast initial hydration rate, high viscosity and poor water resistance hinder its application in the crack repairing engineering. To solve the above problems, the spherical silica fume and fly ash were added into MAPC. The effects of spherical silica fume and fly ash on the rheological property, fluidity, setting time, compressive strength, water resistance and drying shrinkage of MAPC were studied. The results showed that both spherical silica fume and fly ash could reduce the plastic viscosity of MAPC and prolong the setting time. Spherical fly ash could improve the fluidity of MAPC. The late-age strength and water resistance of MAPC were increased and the drying shrinkage was reduced by adding spherical silica fume and fly ash. Therefore, it is concluded that the addition of spherical silica fume and fly ash into MAPC makes it more available to be applied in the crack repairing engineering.

Physical and Mechanical Properties of Novel Porous Ecological Concrete Based on Magnesium Phosphate Cement.

Ecological concrete could reduce the environment impacts of the tremendous construction of infrastructures due to its favorability to plant growth. Nonetheless, the alkalinity of the ecological concrete is usually too high when using ordinary Portland cement (OPC). To solve this problem, the magnesium ammonium phosphate cement (MPC) was used to prepare a novel porous ecological concrete instead of OPC. The pH value and compressive strength of MPC were analyzed and the pore structure was evaluated. The chemical composition and morphology were investigated by an X-ray diffraction test and scanning electron microscope observation. In addition, the void ratio, compressive strength and planting-growing characteristic of MPC-based porous ecological concrete were also studied. The pH value of the MPC suspension ranged from 6.8 to 8.5, which was much lower than that of OPC. The pH value of MPC gradually increased with the increment of phosphorus/magnesium molar ratio (P/M) and the compressive strength reached a maximum value of 49.2 MPa when the P/M value was 1/4. Fly ash (FA) and ground blast furnace slag (GBFS) could improve the pore structure and compressive strength; however, the pH value was slightly increased. As the paste-to-aggregate ratio increased, the void ratio of concrete gradually decreased, while the compressive strength gradually increased. The meadow grass was planted in the MPC-based ecological concrete, and the seeds germinated in one week and showed a better growth status than those planted in the OPC-based ecological concrete.

The complex pathophysiology of urolithiasis (kidney stones) and the effect of combinational drugs

Body organs are very crucial when it comes to homeostatically maintaining them. If any changes occur in their function, it may lead to the development of diseases in the body. The kidney is one of the functionalised organs that is connected with the ureter and urinary bladder, which is basically the lower part of the body. The kidney priorly controls the volume of various body fluids, fluid osmolality, acid-base balance, various electrolyte concentrations, and the removal of toxins. Any dis-balance in the function of the kidney can generate a disease like renal calculi (kidney stone), chronic kidney disease (CKD), polycystic kidney disease (PKD), urinary tract infections (UTI), etc. Kidney stones (KS) are prevalent worldwide, affecting 15% of individuals. A stone arranged into various sizes may be micro, macro, and nano or found as mono or polycrystalline forms. The names of the two most common kidney stones, calcium and non-calcium stones (Uric acid stones, struvite stones, cysteine stones, and drug-induced KS), are determined primarily by their composition. Calcium stones are commonly found in individuals, approximately 80% of KS. This review provided recent details on kidney stone symptoms, etiology, psychophysiology, and management perspective.
 Keywords: Kidney disease, calcium stone, renal calculi, chronic kidney disease, Polycystic kidney disease.

Analysis of the Components of 236 Cases of Urinary Stones in Xinjiang Uyghur Children.

The aim of the study is to explore the relationship between clinical characteristics and urinary calculus in Xinjiang Uyghur children, and to provide clinical basis for the prevention as well as treatment of urinary stone. In total, 236 urinary tract stone samples were collected from pediatric patients from February 2017 to April 2019, and those samples were analyzed by infrared spectroscopy. Stone compositions were compared with demographic data. Among the 236 cases, 166 cases were boys (70.34%) and 70 cases were girls (29.66%), with a male-to-female ratio of 2.37:1. A total of 21 kinds of calculi were detected, including 107 cases with six kinds of simple calculi and 129 cases with 15 kinds of mixed calculi. In this study, magnesium ammonium phosphate hexahydrate was only found in boys, and the difference was statistically significant (6.6 vs. 0.0%, p = 0.037). There were statistical differences in the age distribution of children with ammonium hydrogen urate, calcium oxalate, and other stone components (p < 0.05), while there were no statistical differences in the age distribution of children with apatite carbonate, magnesium ammonium phosphate hexahydrate, and anhydrous uric acid. The results showed that there was a significant difference in the localization of calculi between male and female children (upper urinary tract stones: 78.9 vs. 98.6%, p < 0.001). Uyghur pediatric patients with urolithiasis were young and the majority of stones was mixed, The main components of calculi were ammonium hydrogen urate, calcium oxalate and apatite carbonate, and there are differences in the localization of calculi between genders.

Effect of Citrus Limon (L.), Citrus Aurantium And Citrus Medica On Ethylene Glycol Induced Urolithiasis In Rats

Introduction: Renal stone formation and the predominant chemical stone composition are age and gender dependent. The most common stones are struvite (magnesium ammonium phosphate), calcium oxalate, urate, cystine and silica. The most common type of kidney stones worldwide contains calcium. The process of forming stones in the kidney, bladder, and/or urethra (urinary tract) is called as Urolithiasis. Urinary calculi may cause obstruction, hydronephrosis, infection and hemorrhage in the urinary tract system. Citrus species were used in traditional practices as remedies for the urolithiasis have been well established in vivo-vitro test, clinical trial and effective use but are lacking well documented record. Citrus limon (L.) is tree with evergreen leaves and yellow edible fruits from the family Rutaceae. Citrus aurantiumL commonly called as bitter orange. Citrus medica Linn.,commonly known as a Citron in English and bijapura in Ayurvedic literature is shrub or small tree. All three are reported to use in treatment of wide panel of diseases like antiurolithic activity, stomach ache, vomiting antifungal and antibacterialetc. Urolithiasis was introduced by administration of ethylene glycol in rats. Standard drug treated group, the urinary outputs increased significantly. Body weight of all animals measured on day 0, 14 and 28 of calculi induction to assess the effect of treatment on body weight. The collection of urine from rats scheduled to be every seven days from calculi induction. C. aurantinum extract showed significantly increase in urinary output. The collected urine stored in 4ºC. The analysis of calcium, phosphate, magnesium, creatinine, uric acid, protein, urea nitrogen and oxalate recorded.300 mg/kg of combined extract of all three plants show significant result compare to individual plant response.

Comparative study of Mg-phosphate/cellulose and struvite/cellulose composites: Green synthesis, degradation, and biocompatibility

This present study was mainly aimed at comparing the effect of using two bioresorbable ceramics of the same synthesis origin (Mg-phosphate (MP) and struvite (ST) derived from it) with bacterial cellulose (BC), using bacterial strain Gluconacetobacter xylinum ATCC 10245, to prepare in situ new composites on eco-friendly green synthesis process of the BC, in vitro degradation and biocompatibility. The obtained composites were characterized by TGA, FTIR, and XRD. The in vitro and biodegradation tests were performed in the simulated body fluid (SBF), and the cytotoxicity test was carried out against the Vero cell line. The XRD results showed farringonite and struvite phases were the main crystalline phases. Moreover, the addition of either MP or ST increased the bacterial cellulose yield, and the maximum yield was 1.51–1.56 g/L at a ceramic concentration range 0.25–0.50%. Furthermore, the in vitro bioactivity test presented that bacterial cellulose/struvite composite was the more induced formation of Ca-phosphate layer after immersion in SBF than that of bacterial cellulose/Mg-phosphate composite, and the Ca/P ratio of the former one (Ca/P = 1.11) was closer to the hydroxyapatite ratio (Ca/P = 1.67) the last composite (Ca/P = 0.30). Moreover, bacterial cellulose/struvite showed better compatibility and viability with Vero cells than bacterial cellulose/Mg-phosphate composite. In conclusion, the new bioactive composites synthesized by green and eco-friendly methods are expected to be suitable for bone grafting and engineering applications.

Recovering nutrients and rejecting trace organic compounds in human urine by a forward osmosis-membrane distillation (FO-MD) hybrid system.

Urine is a major source of reclaimed water and fertilizer. Urine treatment involves two key processes: the recovery of nutrients and the rejection of trace organic compounds (TOrCs). In this study, we investigated the rejection of TOrCs and the recovery of nutrients in human urine using a seawater-driven forward osmosis and membrane distillation (FO-MD) hybrid system. Three 24 h experiments were conducted at draw solution temperatures of 30, 40, and 50 °C. The average rejection rates of cations, anions, and dissolved organic carbon were more than 93.7% and 79.5% in the FO-MD system and FO side, respectively. Ten types of TOrCs were detected in the feed solution, whereas none were detected in the product water, indicating that the TOrCs were completely rejected. The precipitates, i.e., the recovered nutrients in the FO side, were extremely close to magnesium ammonium phosphate (struvite, MgNH4PO4·6H2O), according to their electron microscopic images, elemental composition, and X-ray diffraction spectra, and it was estimated that approximately 85% of the nutrients in the feed solution were recovered. The rejection and recovery efficiencies were unaffected by the draw solution temperature. These results indicate the potential for the sustainable use of FO-MD-based treatments for human urine.

Risk factors for postoperative infectious complications after RIRS treatment of kidney and ureteral stones

Abstract&#x0D; Introduction and aim of the study: Urolithiasis is a disease involving the formation of deposits in the lumen of the urinary tract. The continued development of minimally invasive treatment methods allows for more effective treatment with greater operator comfort and less risk to the patient. It has been concluded that retrograde intrarenal surgery (RIRS) is superior to other therapeutic methods in many respects. The aim of this study is to review the available studies and publications and to identify potential complications following treatment of kidney and ureteral stones by RIRS, with a particular focus on infectious complications and their risk factors.&#x0D; &#x0D; Method and materials: We reviewed the literature available on PubMed and Google Scholar, using the words 'urolithiasis'; 'urolithiasis treatment'; 'retrograde intrarenal surgery'; 'infectious complications of retrograde intrarenal surgery'.&#x0D; &#x0D; Results: Among the risk factors associated with infectious complications after RIRS, long duration of surgery, recent positive urine culture, urinary tract infections or antibiotic use, purulent urine, urinary nitrites, obstructed access through the ureter, struvite stones, co-morbidities play a special role.&#x0D; &#x0D; Conclusions: Among the complications of surgical treatment of nephrolithiasis and ureteral stones by RIRS, infectious complications are of particular concern. In view of the knowledge of their risk factors, preventive measures should include limiting the duration of surgery, possible antibiotic therapy and considering the use of a larger diameter UAS. This is especially true for patients with abnormal urine results, struvite stones, a history of urinary tract infection or predisposing comorbidities.&#x0D; &#x0D; Key words: Urolithiasis; Kidney Calculi; Retrograde Intrarenal Surgery; Urolithiasis infection;

Is K-Struvite Precipitation a Plausible Nutrient Recovery Method from Potassium-Containing Wastes?—A Review

The definition of technologies capable of removing and recovering nutrients from polluting effluents is a key environmental challenge. Through these technologies, it would be possible to protect aquatic systems and prevent the consumption of natural resources for the production of commercial fertilizers. In this regard, the application of the precipitation processes of struvite-type compounds is an attractive approach. Indeed, these processes are potentially able to remove nutrients from many effluents and produce a precipitate reusable as a slow-release fertilizer. The scientific community has largely focused on the precipitation of magnesium ammonium phosphate (MgNH4PO4·6H2O, MAP), while the recovery of the analogous magnesium potassium phosphate (MgKPO4·6H2O, MPP) has received extensive attention in the last decade. Research on this topic is continuously progressing to improve the precipitation process in different aspects (working conditions, reaction units, interference elimination, etc.). Until now, there has been no paper that comprehensively reviewed the applicability of MPP precipitation for the removal and recovery of nutrients from aqueous waste. To fill this gap, the present paper aimed to provide an exhaustive analysis of the literature reports on MPP processes to help researchers understand the theoretical and applicative aspects, the main problems, and the need for further research. In this regard, the applications in the treatment of various aqueous wastes were considered. The theoretical concepts, the main process parameters, and the effects of inhibiting substances and impurities are presented. Moreover, the development of reactor configurations and their working conditions are evaluated. Finally, the potential use of MPP as a fertilizer and some economic evaluations are reported. On the basis of the conducted analysis, it emerged that the recovery of MPP was mainly affected by the pH, dose, and nature of reagents, as well as the presence of competitive ions. The optimal pH values were reported to be between 9 and 11. Reagent overdoses with respect to the theoretical values improved the process and the use of pure reagents guaranteed superior performance. The stirred-tank reactors and fluidized bed reactors were the most used units with high process yields. The applicability of MPP in agronomic practices appears to be a suitable option.

Use of a wastewater recovery product (struvite) to enhance subtropical seagrass restoration.

Seagrasses are in decline worldwide, and their restoration is relatively expensive and unsuccessful compared to other coastal systems. Fertilization can improve seagrass growth in restoration but can also release nutrients and pollute the surrounding ecosystem. A slow-release fertilizer may reduce excessive nutrient discharge while still providing resources to the seagrass's rhizosphere. In this study, struvite (magnesium ammonium phosphate), a relatively insoluble, sustainable compound harvested in wastewater treatment plants, was compared to Osmocote™(14:14:14 Nitrogen: Phosphorus: Potassium, N:P:K), a popular polymer coated controlled release fertilizer commonly used in seagrass restoration. Two experiments compared the effectiveness of both fertilizers in a subtropical flow-through mesocosm setup. In the first experiment, single 0.5 mg of P per g dry weight (DW) doses of Osmocote™and struvite fertilizers were added to seagrass plots. Seagrass shoot counts were significantly higher in plots fertilized with struvite than both the Osmocote™and unfertilized controls (p< 0.0001). A significant difference in total P concentration was observed in porewater samples of Osmocote™vs struvite and controls (p< 0.0001), with struvite fertilized plots emitting more than controls (p ≤ 0.0001), but less than 2% of the total dissolved P (TDP) of Osmocote™fertilized plots (100+ mg/L versus x > 5 mg/L). A subsequent experiment, using smaller doses (0.01 and 0.025 mg of P per gram DW added), also found that the struvite treatments performed better than Osmocote™, with 16-114% more aboveground biomass (10-60% higher total biomass) while releasing less N and P. These results indicate the relatively rapid dissolution of Osmocote™may pose problems to restoration efforts, especially in concentrated doses and possibly leading to seagrass stress. In contrast, struvite may function as a slow-release fertilizer applicable in seagrass and other coastal restoration efforts.

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.

Nephrolithiasis management and outcomes in pediatric patients with limited mobility

Pediatric patients with limited lower extremity mobility may be at increased risk of developing nephrolithiasis due to bone mineral metabolic derangements. This study sought to assess whether nephrolithiasis management and related outcomes differ between ambulatory versus non-ambulatory pediatric patients. This was a retrospective review of ambulatory and non-ambulatory pediatric patients with nephrolithiasis from 2010 to 2021 from a single tertiary care center. Demographics, surgical history, stone compositions, and 24-h urine data were reviewed. Adjusted logistic and linear regression models were utilized to assess whether mobility status was associated with nephrolithiasis-related management and outcomes, including: age at first stone; requiring surgical intervention for stones; number of surgeries; stone compositions; urine culture results; and completion of 24-h urine studies. Among 339 pediatric patients with nephrolithiasis, 67 (19.8%) were non-ambulatory. In adjusted analyses, non-ambulatory patients had 3.24 times greater odds of requiring surgical intervention for stones (95% CI: 1.93-6.84; p<0.0001); among those who required surgery, non-ambulatory patients required an average of 0.82 more surgical interventions (95% CI: 0.35-1.30; p=0.0008) than ambulatory patients. Additionally, non-ambulatory patients had 5.28 times greater odds of having a positive urine culture at the time of surgery (95% CI: 2.35-14.08; p=0.0001) and were significantly less likely to undergo 24-h urine studies (OR: 0.35; 95% CI: 0.15-0.83; p=0.02). Stone composition significantly varied by mobility status, with non-ambulatory patients being significantly more likely to form calcium apatite (OR: 5.1; 95% CI: 2.18-11.93; p=0.0002) or struvite (OR 3.72; 95% CI: 1.18-11.74; p=0.03) stones, and significantly less likely to form calcium oxalate stones (OR: 0.19; 95 CI: 0.08-0.47; p=0.0003). Among all patients, age at first stone occurred at a median age of 13.4 years (IQR: 8.2-16.4) and did not significantly differ by mobility status (p=0.92). Patients with limited mobility required surgery for nephrolithiasis at significantly higher rates and had different stone compositions than ambulatory patients. Obtaining a 24-h urine study in patients with comorbidities affecting ambulation was uncommon, compared to ambulatory patients. Similarly to ambulatory patients, pediatric patients with limited mobility who develop nephrolithiasis tend to first present with stones in early adolescence.

Production of struvite by magnesium anode constant voltage electrolytic crystallisation from anaerobically digested chicken manure slurry

Nitrogen and phosphorus levels in livestock manure and digestive fluid are high, posing a threat to soil and water quality and necessitating nutrient removal and recovery. Phosphorus recovery has the potential to alleviate the global phosphorus resource crisis. This study proposed a magnesium anode constant voltage electrolysis method to crystallise struvite (magnesium ammonium phosphate hexahydrate, MgNH4PO4·6H2O) from anaerobically digested chicken manure slurry using reaction kinetics at variable constant voltages ranging from 2 V to 12 V. The recovery of nitrogen and phosphorus was shown to be effective over a wide initial pH range (3.00 ± 0.03–7.90 ± 0.10) using synthetic digestion fluids. Moreover, the pH gradually increased during the reaction without any external chemical adjustments. The phosphorus recovery rates conformed to the first-order kinetic model, with a maximum rate constant of 2.13 h−1. When the best voltage of 2 V was used at 25 ± 1 °C, the recovery rate reached 5.24 mg P h−1cm−2 in the synthetic digestion fluids during 90 min and 4.60 mg P h−1cm−2 in the anaerobically digested chicken manure slurry. The crystalline products recovered were identified as high-purity struvite by XRD and XPS. The purity of recovered struvite with an initial pH of 3.00 and 7.90 was 96.5% and 98.9%, respectively. These results demonstrated that the magnesium electrode could rapidly react with nitrogen and phosphorus to generate high-purity struvite.

How Reliable Is Endoscopic Stone Recognition? A Comparison Between Visual Stone Identification and Formal Stone Analysis.

Objective: To assess the diagnostic accuracy and intra-observer agreement of endoscopic stone recognition (ESR) compared with formal stone analysis. Introduction: Stone analysis is a corner stone in the prevention of stone recurrence. Although X-ray diffraction (XRD) and infrared spectroscopy are the recommended techniques for reliable formal stone analysis, this is not always possible, and the process takes time and is costly. ESR could be an alternative, as it would give immediate information on stone composition. Materials and Methods: Fifteen endourologists predicted stone composition based on 100 videos from ureterorenoscopy. Diagnostic accuracy was evaluated by comparing the prediction from visual assessment with stone analysis by XRD. After 30 days, the videos were reviewed again in a random order to assess intra-observer agreement. Results: The median diagnostic accuracy for calcium oxalate monohydrate was 54% in questionnaire 1 (Q1) and 59% in questionnaire 2 (Q2), whereas calcium oxalate dihydrate had a median diagnostic accuracy of 75% in Q1 and 50% in Q2. The diagnostic accuracy for calcium hydroxyphosphate was 10% in Q1 and 13% in Q2. The median diagnostic accuracy for calcium hydrogen phosphate dihydrate and calcium magnesium phosphate was 0% in both questionnaires. The median diagnostic accuracy for magnesium ammonium phosphate was 20% in Q1 and 40% in Q2. The median diagnostic accuracy for uric acid was 22% in both questionnaires. Finally, there was a diagnostic accuracy of 60% in Q1 and 80% in Q2 for cystine. The intra-observer agreement ranged between 45% and 72%. Conclusion: Diagnostic accuracy of ESR is limited and intra-observer agreement is below the threshold of acceptable agreement.

(Digital Presentation) Enhanced Electrochemical Phosphate Recovery from Wastewater: Implications of Pulsating Anode Potential

Electrochemical recovery of phosphorus (P) as struvite (or magnesium ammonium phosphate hexahydrate, MgNH4PO4.6H2O) fertilizer using a sacrificial pure magnesium (Mg) anode is considered a sustainable strategy to deal with the limited availability of rock phosphate. However, the formation of an electrically passive film of magnesium hydroxide (Mg(OH)2) and/or struvite on the surface of Mg upon immediate immersion in aqueous phosphate solution limits the release of divalent Mg ions and decreases struvite precipitation. The present work highlights struvite recovery by an electrochemical method upon application of a dynamic voltage with a sinusoidal waveform. Our results demonstrate that a dynamic potential, when compared to a constant potential, can enhance the rupture of the passivating film, and facilitate the release of Mg2+ from the metal thereby overcoming the problems related to electrical passivation.Aqueous solutions of ammonium dihydrogen phosphate (NH4H2PO4, 10 mM) at neutral pH were used as test solutions. Mg2+ release was notably increased by ~48% relative to constant voltage applications, which subsequently led to ~20% higher phosphate recovery. Characterization studies including X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated the presence of struvite in the recovered precipitate. Surface characterization of electrodes using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) also confirms a higher extent of passivating film breakdown in the presence of dynamic voltage.