Low Pressure Research Articles

Parametric assessment of size and peak pressure variability for cavitation bubbles induced by low-voltage discharge

Abstract Cavitation presents a significant challenge in the operation and longevity of hydraulic machinery. Studying a single cavitation bubble can provide fundamental insights into the phenomenon. One simple and popular method to generate such bubbles is through a low-voltage discharge between two contacting electrodes to create a spark that locally vaporizes water. This study investigates the repeatability of this method in generating consistent bubbles. The electrode length is one parameter that influences the bubble size. However, the excess length (the electrode length after the contact point) is shown to be the primary variable influencing the bubble size rather than the total electrode length. Additionally, even for bubbles of similar size, significant variability in wall pressure peaks was observed for bubbles generated far from the surface. This variability correlates with the time the electrodes require to melt and break. Longer melting times are associated with extended bubble lifetimes and lower pressure peaks.

Vibron Softening of Solid Hydrogen under Nanoconfinement.

The vibron behavior of hydrogen bears significant importance for understanding the phases of solid hydrogen under high pressure. In this work, we reveal an unusual high-pressure behavior of hydrogen confined within nanopores through a combination of experimental measurements and theoretical calculations. The nanoconfined hydrogen molecules retain an hcp lattice up to 170 GPa, yet significant deviations from the vibrational characteristics of bulk hydrogen are observed in the primary vibrons of both Raman and infrared spectra. This lowered vibron peak is linked to the disorder of the hydrogen molecules with longer bonds and enhanced intermolecular interactions at the interface. Further investigation reveals that this nanoscale confinement leads to a considerable decrease in the band gap of solid hydrogen, potentially facilitating band gap closure at considerably lower pressures. Our findings provide crucial insights into the behavior of solid hydrogen under spatial nanoconfinement, paving the way for novel explorations into hydrogen metallization.

Dual Regulation of Ionic Effect on Zostera marina L. Seed Germination and Leaf Differentiation in Low-Salinity Conditions

Low-salinity conditions are generally used in land-based cultivation to promote the germination and growth of Zostera marina L. and to improve the restoration effect of seagrass beds. Different salinity conditions lead to morphological and physiological differences. To investigate the impacts of salinity and osmotic pressure on the germination and early development of Zostera marina seeds, this study utilized seawater with different salinity conditions and PEG-6000 solutions to simulate various non-ionic osmotic pressures and examine the germination, cotyledon growth, and leaf differentiation over 28 days, as well as determine the biochemical traits on days 1, 3, 5, and 7. The results show that the cumulative germination rate in LS-0 was 91.6%, but it was not significantly affected by the PEG solutions. The different salinities (5, 10, and 15) had no significant effect on the germination rate, which ranged from 76.4% to 78.8%: low salinity and low osmotic pressure stimulated the germination by accelerating the water uptake through increased osmotic pressure differences. The leaf differentiation was regulated by the osmotic pressure and salinity. In LS-10, the most used condition, the leaf differentiation rate was 35.2%, while PEG-10 displayed 6.4%. The total soluble sugar and soluble protein in the seeds decreased. Antioxidant enzyme activities were activated under low-salinity conditions, which supported germination within a tolerable oxidative stress range.

Real time monitoring of intrarenal pressures while using the flexible and navigable suction ureteral access sheath.

To report on in-vivo intrarenal pressure (IRP) during flexible ureteroscopy for treatment of kidney stones while using the novel flexible and navigable suction ureteral access sheath (FANS). A retrospective observational analysis was performed for 25 patients undergoing routine flexible ureteroscopy for treatment of renal stones between February 2024 and June 2024 from two centres in Canada. The LithoVue Elite™ ureteroscope (Boston Scientific Corp., Marlborough, MA, USA) with pressure sensing capability was used together with the Clearpetra® Ureteral Access Sheath System (Well Lead Medical Co. Ltd., Guangzhou, China) for all cases. Irrigation was via a pressure bag set at 250mmHg where possible and the access sheath was connected to wall suction at 200mmHg. Median and maximum IRP, as well as the distribution of cumulative procedure times according to various IRP ranges were analyzed. The median age of the patients was 56 years, with a median BMI of 26.7kg/m2. The median (Interquartile range {IQR}) IRP for all the cases was 22.0 (15.0-36.5) mmHg, with a median (IQR) procedure time of 35.9 (16.4-54.8) minutes. The IRP remained below 40mmHg in 76.2% of the total time in all procedures, and was below 60mmHg in 94.1% of the time. Significant variables associated with lower IRP were having a prior endourological procedure, pre-stenting, larger ureteral access sheath size and use of pre-operative alpha blocker. Age, BMI and total stone volume did not significantly affect IRP. Low intrarenal pressures can be achieved with the use of FANS, even with higher irrigation pressures. Alpha blocker use, larger sheath size, prior endourological procedures and pre-stenting are all associated with lower IRP.

Lactobacillus-Loaded Easily Injectable Hydrogel Promotes Endometrial Repair via Long-Term Retention and Microenvironment Modulation.

Regeneration of the injured endometrium, particularly the functional layer, is crucial for the prevention of uterine infertility. At present, clinical treatment using sodium hyaluronate hydrogel injection is limited by its relatively low fluidity, short-term retention, and insufficient bioactive ingredients, so it is necessary to develop an advanced healing-promoting hydrogel. The modulation of the microenvironment by Lactobacillus presents a bioactive component that can facilitate the regeneration of the functional layer. Our study introduces a multifunctional Lactobacillus-loaded poly(N-isopropylacrylamide)-grafted bacterial cellulose (BC-g-PN@L) hydrogel designed with superior injectability and in situ stability. At 25 °C (room temperature), a uniform distribution is achieved with a low injection pressure of only 7.90 kPa. At 37 °C (body temperature), the BC-g-PN@L hydrogel forms a robust three-dimensional nanonetwork, providing space and substance exchange channels for Lactobacillus to maintain its viability and bioactivity. Enhanced by the hydrophobic isopropyl groups in poly(N-isopropylacrylamide) side chains and the rigid bacterial cellulose substrates, the BC-g-PN@L hydrogel exhibits prolonged retention properties in the uterine cavity, persisting for over 21 days. These attributes endow the BC-g-PN@L hydrogel with versatile pro-healing capacity and microenvironment modulation in a rat model of endometrial injury. Our BC-g-PN@L hydrogel promotes the development of advanced injectable hydrogels to facilitate both histological and functional repair of the injured endometrium.

Unboxing: Exploring the Challenges of Green Supply Chain Initiatives in Thailand

Background: The increasing global focus on sustainability has made Green Supply Chain Management (GSCM) a critical strategy for businesses to balance environmental responsibility with operational efficiency. Despite its benefits, GSCM adoption in developing countries faces significant challenges. This study addresses the gap by investigating these barriers within the Thai context, providing actionable insights for policymakers and businesses. Methods: A mixed-methods approach was employed, including a survey of 480 business owners, executives, and supply chain employees, and expert analysis using Interpretive Structural Modeling (ISM). The ISM technique was used to determine the relationships and hierarchy among key barriers to GSCM implementation. Results: The findings reveal that weak legal frameworks, insufficient supplier engagement, and a lack of social responsibility are the most significant barriers. Secondary factors, such as low consumer demand and minimal competitive pressure, exacerbate these challenges. The ISM analysis highlighted the cascading effects of foundational barriers on other dimensions of GSCM adoption. Conclusions: Strengthening environmental regulations, promoting supplier collaboration, and embedding sustainability in corporate culture are key to overcoming GSCM barriers to sustainably enhance Thailand’s competitiveness.

Improved snow albedo evolution in Noah-MP land surface model coupled with a physical snowpack radiative transfer scheme

Abstract The widely-used community Noah-MP land surface model currently adopts snow albedo parameterizations that are semi-physical in nature and have systematic biases which impact the accuracy of weather and climate modeling systems that use Noah-MP as the land component. We hypothesized that integrating the snowpack radiative transfer scheme from the latest version of the Snow, Ice, and Aerosol Radiative (SNICAR) model can improve the physical representation of snow albedo processes and reduce corresponding land model uncertainties. Therefore, we evaluate Noah-MP simulations employing the SNICAR scheme and compare model accuracy to a Noah-MP simulation using the default semi-physical Biosphere-Atmosphere Transfer Scheme (BATS) scheme using in-situ spectral snow albedo observations at three Rocky Mountain field stations. The agreement between simulated and in-situ observed ground snow albedo is significantly enhanced in NoahMP-SNICAR simulations relative to NoahMP-BATS simulations (root mean square error reductions from 0.116 to 0.103). Especially, NoahMP-SNICAR improves modeled snow albedo variability for fresh snow and aged snowpack (correlation increase from 0.42 to 0.67). The underestimated variability of snow albedo in NoahMP-BATS is a result of inadequate representation of physical linkages between snow albedo evolution and environmental/snowpack conditions (temperature, snow density, snow water equivalent, and light-absorbing particles), which is substantially improved by the NoahMP-SNICAR scheme. This new development of NoahMP-SNICAR physics provides a means to improve snow albedo accuracy and reduce corresponding uncertainties while providing new modeling capabilities such as hyperspectral snow albedo, and effects of snow grain size, snow grain shape, and light-absorbing particles in future studies.

Genetic and Structural Factors Contributing to the Dominance and Persistence of Goose Astrovirus Type 2

: Goose astrovirus (GoAstV) has emerged as a significant pathogen affecting the goose industry in China, with GoAstV-2 becoming the dominant genotype since 2017. This study explores the genetic and structural factors underlying the prevalence of GoAstV-2, focusing on codon usage bias, spike protein variability, and structural stability. Phylogenetic and effective population size analyses revealed that GoAstV-2 experienced rapid expansion between 2017 and 2018, followed by population stabilization. Codon usage analysis indicated that GoAstV-2 exhibited a weaker codon usage bias compared to GoAstV-1, suggesting greater flexibility in synonymous codon usage and potentially enhanced adaptability across host environments. Additionally, GoAstV-2's lower codon adaptation index values point to a divergence from the host’s optimal codon usage, which may reduce competition with host tRNA pools and facilitate viral replication. The spike protein of GoAstV-2 demonstrated significantly lower variability than GoAstV-1, as shown by Shannon entropy analysis, indicating greater structural stability. This stability may reduce the need for frequent mutations, allowing GoAstV-2 to persist in host populations without undergoing constant evolution. The lower antigenic variability likely decreases immune-driven selective pressure, contributing to the viral sustained transmission and long-term persistence. These findings provide new insights into the evolutionary advantages of GoAstV-2 and its epidemiological success, which could inform future control strategies aimed at mitigating its impact on poultry populations.

Medical Problems of Chronic Hypoxia in Highlanders Living on the Tibetan Plateau.

Ri-Li Ge. Medical problems of chronic hypoxia in highlanders living on the tibetan plateau. High Alt Med Biol. 00:00-00, 2024.-Health issues at high altitudes arise due to the lower atmospheric pressure and subsequent reduction in the partial pressure of oxygen in ambient air. While much research has been published on health problems of lowlanders who move to high altitudes, less is known about the medical challenges faced by long-term and permanent high-altitude residents, especially in the Qinghai-Tibetan plateau. In this review, we briefly summarized the chronic hypoxia-related health issues in highlanders, focusing on the specific population of the Qinghai-Tibetan plateau. It deals with important health problems for highlanders, including the main disease categories, from chronic mountain sicknesses and pulmonary hypertension (PH) to kidney, neurocognitive impairments, perinatal problems, and congenital heart defect. However, the most hallmark of disorders is excessive erythrocytosis associated with specific symptoms and signs, and high-altitude heart disease is characterized by excessive PH, right ventricular hypertrophy, and right heart failure. We also provide information on potential treatment strategies, including some traditional Tibetan medical practices and also a combination of Western medicine and traditional Chinese medicine to prevent and treat these conditions effectively. This mini-review is heavily based on a couple of decades of research carried out by Chinese high-altitude medical research groups at the Qinghai-Tibetan Plateau. We believe that this review will provide valuable perspective to researchers whose study interest and base lie in high altitude.

Phytic Acid-Induced Gradient Hydrogels for Highly Sensitive and Broad Range Pressure Sensing.

Ionic conductive hydrogels have emerged as an excellent option for constructing dielectric layers of interfacial iontronic sensors. Among these, gradient ionic hydrogels, due to the intrinsic gradient elastic modulus, can achieve a wide range of pressure responses. However, the fabrication of gradient hydrogels with optimal mechanical and sensing properties remains a challenge. In this study, it is discovered first that phytic acid (PA) interacts in remarkably distinct manners (i.e., plasticizing effects and phase separation) with different polymers (i.e., polyacrylamide and polyacrylic acid). This distinctive PA-polymer interacting mechanism is innovatively utilized to construct a modulus gradient ionic hydrogel through a simple precursor solution infiltration approach. The gradient hydrogel-based flexible pressure sensor not only achieves a high sensitivity (9.00kPa-1, <15kPa) and a broad sensing range (from ≈3.7Pa to 1.2MPa) simultaneously, but also exhibits superior low pressure sensing performance. It successfully recognizes the subtle pressure due to acoustic waves and airflow, as well as the moderate pressure due to speaking and finger pressing and the high magnitude of plantar pressure. In addition, the gradient hydrogel demonstrates remarkable antibacterial properties and biocompatibility. This functional hydrogel with excellent sensing performance and bioactivity exhibits exceptional potential for wearable sensing applications.

Short-term impact of low air pressure on plants' functional traits.

Lower atmospheric pressure affects biologically relevant physical parameters such as gas partial pressure and concentration, leading to increased water vapor diffusivity and greater soil water content loss through evapotranspiration. This might impact plant photosynthetic activity, resource allocation, water relations, and growth. However, the direct impact of low air pressure on plant physiology is largely unknown. This study examined the effects of low air pressure, alone and combined with two water inputs, on different functional traits of three plant species transplanted from montane grasslands at 1,500 m a.s.l. during the first four weeks of their early phenological stage: Trifolium pratense, Hieracium pilosella, and Brachypodium rupestre. Using the terraXcube Ecotron facility which can simulate different climatic conditions, we isolated the effect of air pressure from those of other, related environmental factors (temperature, humidity, and solar radiation) by simulating three different elevations with corresponding air pressures: 1,500 m a.s.l. (85 kPa, control scenario), 2,500 m a.s.l. (75 kPa), and 4,000 m a.s.l. (62 kPa) and we used two different water regimes to observe the combined effect of low air pressure and the impact of varying water inputs on plants. In T. pratense and H. pilosella, we observed an increase in stomatal conductance but a reduction in aboveground biomass at the lowest pressure compared to the control scenario after four weeks of incubation. Contrastingly, B. rupestre showed an interactive effect of air pressure and water treatment on chlorophyll and biomass nitrogen content, which were reduced under higher soil water conditions at 85kPa. This study serves as an initial step in isolating the specific impact of air pressure on plant physiology, demonstrating the potential of the facility for future research. The mixed response patterns across species highlight that atmospheric pressure could be a driving factor to consider when assessing plant responses along elevational gradient.

Design of High-Temperature Superconducting Ternary Hydride NaY3H20 at Moderate Pressure via Introducing Hydrogen Vacancies.

Superconducting hydrides exhibiting a high critical temperature (Tc) under extreme pressures have garnered significant interest. However, the extremely high pressures required for their stability have limited their practical applications. The current challenge is to identify high-Tc superconducting hydrides that can be stabilized at lower or even ambient pressures. Here, we propose a strategy for designing high-Tc superconducting hydrides at low pressures by introducing defects into the hydrogen frameworks of clathrate hydrides. We present a type of hydrogen-vacancy structural type AB3H20 derived from type-I clathrate hydrides and identified a stable NaY3H20 through high-throughput calculations. Further calculations show that NaY3H20 is thermodynamically stable above 133 GPa and dynamically stable down to 20 GPa, with a predicted high Tc of approximately 115 K. It significantly reduces the pressure required for stability compared to that of type-I clathrate hydrides with high Tc. Our results provide a foundation for further exploration of high-Tc superconducting hydrides at lower pressures or even ambient conditions.

Rheological Behavior of Gassy Marine Clay: Coupling Effects of Bubbles and Salinity

Understanding the rheological behavior of marine clay is crucial to analyzing submarine landslides and their impact on marine resource exploitation. Dispersed bubbles in marine clay (gassy clay) and electrolytes in seawater (e.g., NaCl concentration of 0.47 M) significantly impacts rheological properties. Under low ionic strength and low pore water pressure conditions, dispersed bubbles have a strengthening effect on the yield stress and the viscosity of clays. This effect turns into a weakening effect when the pore water pressure reaches 300 kPa or the ionic strength exceeds 0.18 M. It was proposed that the effect of bubbles, whether strengthening or weakening, was determined by the size of bubbles with respect to the characteristic size of the particle structure formed by clay particles. A theoretical model was developed, which reasonably captures rheological behaviors of gassy clays.

Tele-mentorship versus in-person mentorship for trainee performance of cricothyroidotomy

Introduction Physicians and other first-line medical care providers may find themselves in an airway management emergency where they cannot ventilate, cannot oxygenate, and have limited resources to aid them. The rise in use of tele-health and other virtual interfaces creates the opportunity to bring experienced guidance to a resource-poor critical airway situation. We aimed to compare in-person mentoring (IPM) by an emergency medicine (EM) physician to tele-mentoring (TM) by a trauma surgeon for an emergent surgical airway. Methods Thirty EM residents were randomized to cricothyroidotomy on a model with IPM or TM. The IPM preceptor was an EM attending, and TM preceptors were trauma surgeons. The procedure was timed and graded on a Global Rating Scale (GRS). Post-procedure, mentor and trainee completed a NASA Task Load Index (TLX). Results There was no difference in procedure success; however, the IPM group took longer (163.6 vs. 107.6 s, p &lt; 0.05). TM trainees experienced greater temporal demand (4.27 vs. 2.73, p = 0.03). Telementors recorded improved performance compared to in-person mentors (2.30 vs. 4.17, p &lt; 0.05). Comparing mentors and trainees in each arm, IPM trainees felt more temporal demand than their mentors (4.63 vs. 2.73, p &lt; 0.05) while TM trainees felt they had worse performance than their mentors perceived (4.23 vs. 2.3, p = 0.01). Discussion Performance based on GRS between groups was equal; however, those with telementors secured the airway more rapidly. Telementors reported higher performance and lower time pressure than in-person preceptors. This data suggests that TM is effective for precepting cricothyroidotomy and may be the superior option in some settings.

Passivating Lattice Oxygen in ZnO Nanocrystals to Reduce its Interactions with the Key Intermediates for a Selective Photocatalytic Methane Oxidation to Methanol

An inevitable overoxidation process is considered as one of the most challenging problems in the direct conversion of methane (CH4) to methanol (CH3OH), which is limited by the uncontrollable cracking of key intermediates. Herein, we have successfully constructed a photocatalyst, the Fe‐doped ZnO hollow polyhedron (Fe/ZnOHP), for the highly selective photoconversion of CH4 to CH3OH under mild conditions. In‐situ experiments and density functional theory calculations confirmed that the introduction of Fe was able to decrease the energy level of the O 2p orbital, which passivated the activity of lattice oxygen in ZnO nanocrystals. This passivation effect greatly weakened the interaction between *CH3 and lattice oxygen, thus facilitating the conversion of *CH3O to *CH3 intermediate rather than the direct desorption of *CH3O. As a result, Fe/ZnOHP exhibited excellent CH3OH generation rate (ca. 1009 μmol gcat−1 h‐1) and selectivity (ca. 96%) in the photocatalytic conversion of CH4 at room temperature and low pressure.

Passivating Lattice Oxygen in ZnO Nanocrystals to Reduce its Interactions with the Key Intermediates for a Selective Photocatalytic Methane Oxidation to Methanol.

Aninevitable overoxidation process is considered as one of the most challenging problems in the direct conversion of methane (CH4) to methanol (CH3OH), which is limited by the uncontrollable cracking of key intermediates. Herein, we have successfully constructed a photocatalyst, the Fe-doped ZnO hollow polyhedron (Fe/ZnOHP), for the highly selective photoconversion of CH4 to CH3OH under mild conditions.In-situ experiments and density functional theory calculations confirmed that the introduction of Fe was able to decrease the energy level of the O 2p orbital, which passivated the activity of lattice oxygen in ZnO nanocrystals. This passivation effect greatly weakened the interaction between *CH3 and lattice oxygen, thus facilitating the conversion of *CH3O to *CH3 intermediate rather than the direct desorption of *CH3O. As a result, Fe/ZnOHP exhibited excellent CH3OH generation rate (ca. 1009 μmol gcat-1 h-1) and selectivity (ca. 96%) in the photocatalytic conversion of CH4 at room temperature and low pressure.

Influence of large-scale atmospheric circulation and Mediterranean Sea surface temperature to extreme land precipitation: the case of storm Alex

Abstract Extreme (greater than 500 mm) amount of rain fell in southeastern France and northern Italy on 2nd and 3rd October 2020 during a "Mediterranean episode" triggered by the powerful extratropical cyclone Alex. Here we use a dynamical adjustment methodology based on constructed analogues to assess the contributions of different drivers to the magnitude of this extreme precipitation event. We first show that the mean effect of the observed atmospheric circulation pattern, an intense low-pressure system centered over the coasts of Western Europe associated with a cold pool and a secondary low-pressure system, can explain about 80 percent of the precipitation event magnitude. By contrasting the effect of Alex atmospheric circulation with an anomalously warm Mediterranean sea and eastern Atlantic ocean versus neutral sea surface temperature conditions, we show that the influence of September 2020 positive sea surface temperature anomalies can explain a large fraction of the 20 percent residual precipitation over southeastern France and northern Italy. Finally, based on a storyline approach, we find that the dynamic component, the atmospheric circulation contribution to the extreme precipitation event, was more extreme than it would have been, had it occurred during the mid-20th century. The increase in the magnitude of the dynamic component since 1950 follows a Clausius-Clapeyron scaling, in agreement with previous studies about the intensity changes of Mediterranean extreme precipitation episodes. (limit =300 words)&amp;#xD;

Vascular endothelial growth factor-C increases lymphatic vessels in the conjunctiva and maintains low intraocular pressure after trabeculectomy in rabbits

The aim of this study is to determine the effect of Vascular Endothelial Growth Factor-C (VEGF-C) in stimulating the growth of functional lymphatic vessels of postoperative conjunctival filtration blebs in rabbits. Twelve New Zealand Red Eye rabbits were allocated to four treatment groups, each receiving an injection of recombinant VEGF-C at doses of 0 µg (control), 1 µg, 3 µg, and 10 µg following trabeculectomy surgery. The effects of the VEGF-C injection on lymphatic vessels were analyzed using FLT4 fluorescence immunostaining and trypan blue filling techniques. Additionally, vascular vessels were examined using CD31 immunostaining, and post-surgical intraocular pressure (IOP) was compared across the treatment groups. Lymphatic vessels in treatment groups exhibited higher mean values of 11.7, 12.7, and 19.0 in groups treated with 1 µg, 3 µg, and 10 µg of VEGF-C, respectively, compared to a mean value of 5.3 in the control group (p = 0.00). Blood vessel count revealed using CD31 did not indicate any increase in vascular vessels between the groups. Intraocular pressure (IOP) levels ten days after trabeculectomy were significantly lower in the 3 µg and 10 µg treatment groups (7.00 mmHg) compared to 10.33 mmHg in the control group (p = 0.047). The study demonstrates that trabeculectomy augmented with VEGF-C injection in rabbits results in an increased lymphatic vessel count in the conjunctiva and a decrease in IOP levels on the tenth post-operative day. These findings suggest that VEGF-C may be a potential adjuvant agent for enhancing the efficacy of trabeculectomy.

Short-Term Safety and Efficacy of PreserFlo™ Microshunt in Patients with Refractory Intraocular Pressure Elevation After Dexamethasone Implant Intravitreal Injection

Background: The PreserFlo™ MicroShunt (PFMS) is a bleb-forming device considered to be less invasive than traditional glaucoma surgery such as trabeculectomy. This study evaluates the 1-year success rates as well as safety profile of PFMS in patients having high intraocular pressure (IOP) and/or glaucoma refractory to drop therapy with a history of prior intravitreal dexamethasone therapy. Methods: A total of 16 eyes after PFMS implantation due to elevated IOP after intravitreal dexamethasone implant (DEX-I) administration were included in this retrospective cohort study. Success rates and secondary outcomes were evaluated. Results: Qualified and complete success rates at 12 months, respectively, were 14/16 and 12/16 eyes for criterion A, 13/16 and 11/16 eyes for B, 13/16 and 11/16 eyes for C, and 6/16 and 6/16 eyes for D. The overall mean (range) preoperative IOP decreased from 27 (16–38) mmHg to 13 (10–17) mmHg at 12 months. BCVA was not significantly different up to 12 months (p = 0.63). The preoperative mean (range) number of medications decreased from 3.56 (2–4) to 0.31 (0–3) at 12 months. One eye underwent needling twice, and two eyes were revised surgically. One patient needed replacement of the PFMS. There were no hypotony-related complications. Conclusions: The PFMS is an effective surgical option for patients with steroid-induced IOP elevation. It demonstrates satisfactory short-term success rates, a reduced need for pressure-lowering eye drops, an excellent safety profile with minimal postoperative care, and a low complication rate. Additional interventions such as needling or revisions were infrequently necessary. However, PFMS may not be the ideal choice for cases requiring a low target pressure (≤12 mmHg).

Can preoperative urodynamic studies predict de novo stress urinary incontinence following advanced pelvic organ prolapse surgery?

Introduction: We aimed to assess the predictivity of preoperative urodynamics (UDS) on de novo stress urinary incontinence (SUI) in patients having advanced pelvic organ prolapse (POP). Methods: Between January 2016 and June 2019, 133 patients with symptomatic POP at stage 3 or higher were included in the study. The presence of postoperative SUI symptoms after a minimum of six months of followup was considered the primary outcome. The results of all patients' preoperative UDS were compared to their postoperative SUI symptoms. In addition, patients were divided into two groups based on whether SUI was detected during preoperative UDS testing (Group 1) or not (Group 2). Results: Although preoperative measurements, such as bladder capacity and residual urine volume, were not different between groups, group 1 had lower maximal urethral closure pressures (p=0.001). Preoperative SUI symptoms had a sensitivity of 32.1% and a specificity of 91.4% for predicting de novo SUI. In patients with advanced POP, preoperative UDS had a sensitivity of 60.7% and a specificity of 87.6% for predicting de novo SUI. Conclusions: Urodynamic examination with a pessary can significantly predict the development of de novo SUI.