Short-Time Changes of Intraocular Pressure and Biomechanics of the Anterior Segment of the Eye during Water Drinking Test in Patients with XEN GelStent

Purpose: Little is known about short-term changes in intraocular pressure (IOP) following minimally invasive glaucoma surgeries, such as post-XEN GelStent implantation. Although the importance of corneal biomechanics in glaucoma diagnostics has been reported, little work has been conducted on postoperative description of changes when the structure of the anterior segment is altered. The aim of presented study was to evaluate the changes in the biomechanical parameters of the anterior segment of the post-XEN GelStent implantation eyes. Patients and Methods: This investigator-initiated, open-label, prospective, single-center study recruited patients. Patients with primary open-angle glaucoma (POAG) after XEN GelStent implantation versus matched POAG controls (considered as control group/CG) treated pharmacologically were screened. Water loading was conducted using 10 mL of water per kilogram of body weight for ≤5 min. Goldmann applanation tonometry (GAT), corneal hysteresis (CH), and corneal resistance factor (CRF) were performed before water loading and after every 15 min up to 1 h. Results: The water drinking test (WDT) was positive in 3.7% (1 out of 27) of patients in the post-XEN group compared with 22.7% (5 out of 22) of patients in the control group (CG; p < 0.05). Mean fluctuations in GAT during the WDT were higher in the CG group (3.6 ± 2.5 mmHg vs. 2.9 ± 1.3 mmHg, p < 0.001). CRF and CH changed significantly only in the post-XEN group. The mean peak of CH and CRF occurred at 15 and 30 min of the test in the post-XEN group (p = 0.001). Conclusion: WDT is important to assess the ability of compensation mechanisms to reduce fluctuations in IOP after water upload. The relationship between biomechanics of the anterior segment and glaucoma may have substantial impact on surgical outcome evaluation.

A Monsoon-Filled Reservoir Might Have Nudged a Fault to Fail

New research examines whether a sudden increase in water loading in Pakistan’s Mangla Dam might have been connected to the 2019 New Mirpur earthquake.

Case History of Matrix Acid Stimulation using Specialized Acid Composition for High Temperature Carbonate Formation and Long Interval Section

Alur Siwah field is located onshore in Block A PSC of PT Medco E&P Malaka, Aceh Province. Six of the ten drilled wells proved significant gas column in Peutu limestone and Tampur dolostone. Well tests indicated gas rates in the range of 0.2 – 42 MMSCFD from selected intervals in both formations. Estimated permeability values from well tests are in range of 0.6 – 3.7 mD. During drilling campaign in 2018 three wells was drilled with total depth around 9,500 ft TVD. AS-9A, AS-11 and AS-12 wells penetrated Peutu Limestone and TD was 213 ft TVD above common GWC. These three wells were completed with open hole and pre-drilled liner, the interval length ranging from 300 to 500 ft-MD. Since Peutu limestone has low permeability the reservoir needs stimulation to increase productivity, maintain gas sales according to GSA (Gas Sales Agreement), and optimize reservoir depletion. Matrix acidizing treatment was applied to remove formation damage. The method was proven successful in previous well at Alur Siwah field in 1990’s. Peutu limestone challenges are high temperature (360 degF), high CO2 (up to 25%), high H2S content (up to 12,000 ppm), long interval open hole section (300-500 ft-MD), and water encroachment risk from water bearing zone. High temperature will accelerate acid reaction, and premature reaction might occur before reaching the reservoir. High CO2 & H2S might cause corrosion at completion string. Penetration into water bearing could cause water encroachment and water loading issue. With proper fluid selection, acid placement method, volume treatment design and execution, matrix acidizing can be applied safely and successfully to stimulate high temperature gas wells which have long interval open hole section completed with pre-drilled liner without water loading issue. This paper covers the application of acid stimulation in Alur Siwah field, well completion, post treatment well performance, best practices and lessons learned.

The Role of Water Loading and Germanium Content in Germanosilicate Hydrolysis

New zeolitic frameworks can be prepared through the Assembly-Disassembly-Organisation-Reassembly (ADOR) process by exploiting the lability of Ge-O bonds in germanosilicate zeolites to control their hydrolysis. In the disassembly step, two key factors are water and germanium content, but their exact roles remain unknown. Nevertheless, we combined experimental water-vapor adsorption with first principles simulations to identify the mechanism of germanosilicate zeolite disassembly. The results showed that water vapor adsorption on <b>UTL</b> germanosilicate proceeds in reversible (at low partial pressures) and irreversible (at higher partial pressures) modes. Based on our ab initio molecular dynamics simulations, we related these two modes to weak physisorption at low water loading and to reactive transformations at high water loading, via collective mechanisms requiring high local water concentrations. This bimodal behavior also depends on the germanium content as high Ge-content further decreases <b>UTL</b> hydrolytic stability by opening up yet another low-energy disassembly pathway at high water loading. Overall, we discovered, verified and explained the mechanisms of <b>UTL</b> disassembly and its factors. These findings will likely be generalized to other ADORable germanosilicate zeolites and help to find the optimal protocol for the synthesis of new zeolites.

The Role of Water Loading and Germanium Content in Germanosilicate Hydrolysis

New zeolitic frameworks can be prepared through the Assembly-Disassembly-Organisation-Reassembly (ADOR) process by exploiting the lability of Ge-O bonds in germanosilicate zeolites to control their hydrolysis. In the disassembly step, two key factors are water and germanium content, but their exact roles remain unknown. Nevertheless, we combined experimental water-vapor adsorption with first principles simulations to identify the mechanism of germanosilicate zeolite disassembly. The results showed that water vapor adsorption on <b>UTL</b> germanosilicate proceeds in reversible (at low partial pressures) and irreversible (at higher partial pressures) modes. Based on our ab initio molecular dynamics simulations, we related these two modes to weak physisorption at low water loading and to reactive transformations at high water loading, via collective mechanisms requiring high local water concentrations. This bimodal behavior also depends on the germanium content as high Ge-content further decreases <b>UTL</b> hydrolytic stability by opening up yet another low-energy disassembly pathway at high water loading. Overall, we discovered, verified and explained the mechanisms of <b>UTL</b> disassembly and its factors. These findings will likely be generalized to other ADORable germanosilicate zeolites and help to find the optimal protocol for the synthesis of new zeolites.

Physical Modeling of Floor Failure Above Confined Water: A Case Study in China

Coal mining in areas with deep confined water is very dangerous; to ensure safety, it is necessary to clarify the damage characteristics of the working face floor. To directly reflect the failure characteristics of the working face floor under the coupled effects of mining stress and confined water pressure, this study takes the II633 working face of the Hengyuan coal mine in the Huaibei mining area as the engineering background. With the use of a self-designed monitoring system for confined water diversion and a similar material simulation experimental method, the mining stress distribution patterns, the deformation and failure characteristics of the overburden, and the diversion characteristics of the confined water in the working face floor are studied. The combined use of a confined water loading system and a confined water lifting system can directly reproduce the floor confined water lifting characteristics affected by floor failure during coal mining. The results show that the floor undergoes three stages of deformation in the horizontal direction: premining stress concentration compression (10-15 m ahead of the working face), postmining floor pressure relief expansion, and roof collapse stress recovery (the distance of the lagging working face is 15-20 m). In the vertical direction, a soft rock layer blocks the continuous transfer of mining stress to deeper layers and produces an important cushioning effect. In the process of coal mining, shear cracks easily develop in the coal wall in front of and behind the working face. After the coal seam is excavated, the length of the fractures that develop in the model is 27 cm. The confined water loading system can visually reproduce the hydraulic characteristics of the confined water during the mining process; that is, the confined water easily bursts at the front and back ends of the coal wall in the goaf. The error, as determined by comparison between the field measurement and the theoretical calculation results, is only 0.617 m, verifying the reliability of the similar simulation method.

Comparing Approaches to Normalize, Quantify, and Characterize Urinary Extracellular Vesicles

BackgroundUrinary extracellular vesicles (uEVs) are a promising source for biomarker discovery, but optimal approaches for normalization, quantification, and characterization in spot urines are unclear.MethodsUrine samples were analyzed in a water-loading study, from healthy subjects and patients with kidney disease. Urine particles were quantified in whole urine using nanoparticle tracking analysis (NTA), time-resolved fluorescence immunoassay (TR-FIA), and EVQuant, a novel method quantifying particles via gel immobilization.ResultsUrine particle and creatinine concentrations were highly correlated in the water-loading study (R2 0.96) and in random spot urines from healthy subjects (R2 0.47–0.95) and patients (R2 0.41–0.81). Water loading reduced aquaporin-2 but increased Tamm-Horsfall protein (THP) and particle detection by NTA. This finding was attributed to hypotonicity increasing uEV size (more EVs reach the NTA size detection limit) and reducing THP polymerization. Adding THP to urine also significantly increased particle count by NTA. In both fluorescence NTA and EVQuant, adding 0.01% SDS maintained uEV integrity and increased aquaporin-2 detection. Comparison of intracellular- and extracellular-epitope antibodies suggested the presence of reverse topology uEVs. The exosome markers CD9 and CD63 colocalized and immunoprecipitated selectively with distal nephron markers.Conclusions uEV concentration is highly correlated with urine creatinine, potentially replacing the need for uEV quantification to normalize spot urines. Additional findings relevant for future uEV studies in whole urine include the interference of THP with NTA, excretion of larger uEVs in dilute urine, the ability to use detergent to increase intracellular-epitope recognition in uEVs, and CD9 or CD63 capture of nephron segment–specific EVs.

Dysregulation mechanism of the influence of water of negative redox potential on kidney function

Elucidate the dysregulatory mechanism of the effect of water load of negative redox potential in comparison with induced diuresis with ordinary tap water on the functional state of the kidneys.Material and methods. The experiments were carried out on 40 male white nonlinear rats weighing 0.16-0.18 kg with the analysis of the effect of water loading with a negative redox potential on renal function, which was obtained by treating tap water with microhydrin. The redox potential of water and urine was determined with an ORP meter. From the indicators of renal function studied: protein excretion, glomerular filtration, filtration fraction of sodium ions, its absolute and proximal reabsorption. Statistical processing of the data obtained, including multivariate regression analysis, was carried out using the Statgrafics, Statistica, and Excel 2003 programs.Results. Comparative multivariate analysis of the effect of water loading of negative redox potential in comparison with induced diuresis with ordinary tap water revealed an ambiguous nature of reliable correlations (p <0.05) between the studied indicators of renal function and the redox potential of urine, which is due to the simultaneous presence of both protective mechanisms of negative redox potential influence (improvement of energy supply, antioxidant effect), and damaging (transient renal ischemia due to activation of the basal tone mechanism due to an increase in the contractile function of the heart as a result of improving its energy supply), the final result will depend on the dominance of classical or dysregulation mechanisms in this particular situation. Conclusion. The dysregulation mechanism of the effect of water of negative redox potential on renal function is due to the initial mobilization of defense reactions with improved contractile function of the heart, which is subsequently transformed into an injury response due to increased basal renal vascular tone with the development of transient ischemia and renal dysfunction, decrease оf glomerular filtration, filtration fraction of sodium ions, its absolute and proximal reabsorption and development of proteinuria.