Fluid Discharge Research Articles

Improved sexuality and satisfactory lubrication after genital affirmation surgery using penile skin inversion in transgender women: A satisfaction study

Genital affirmation surgery (GAS) requests are consistently increasing in demand. The gold standard is penile skin inversion, using cutaneous grafting for neovagina creation. The aim is to achieve the most realistic results both physically and functionally. Different studies have contradictory results, and the use of lubrication is insufficiently clear, while the use of sigmoidoplasty has been defended for constant lubrication. Our aim was to evaluate transgender women's sexual function and lubrication after vaginoplasty by penile skin inversion. We performed a prospective study on 45 patients who underwent primary penile inversion vaginoplasty. Participants answered two questionnaires during the follow-up consultation: the Female Sexual Function Index (FSFI) and an 18-item custom questionnaire. The average FSFI score of our patients was 28.9, up to the cut-off defining a sexual disorder. Compared to the Wylomanski control group, no differences were found for the FSFI score and in the subgroups. Considering lubrication, 69% of the patients were satisfied or very satisfied with their lubrication. Furthermore, 53% reported a fluid release at each orgasm. This study reported high satisfaction for both sexuality and lubrication, proning against penile inversion's GAS bad reputation concerning postoperative lubrication. A squirting effect was described for the first time and was present in 53% of our transpatients.

Simultaneous hydrodynamic cavitation and nanosecond pulse discharge plasma enhanced by oxygen injection

A novel Hydrodynamic Cavitation-Assisted Oxygen Plasma (HCAOP) process, which employs a venturi tube and oxygen injection, has been developed for enhancing the production and utilization of hydroxyl radicals (·OH) in the degradation of organic pollutants. This study has systematically investigated the fluid characteristics and discharge properties of the gas–liquid two-phase body in the venturi tube. The hydraulic cavitation two-phase body discharge is initiated by the bridging of the cavitation cloud between the electrodes. The discharge mode transitions from diffuse to spark to corona as the oxygen flow rate increases. The spark discharge has the highest current and discharge energy. Excessive oxygen results in the change of the flow from bubbly to annular and a subsequent decrease in discharge energy. The effects of cavitation intensity, oxygen flow rate, and power polarity on discharge characteristics and ·OH production were evaluated using terephthalic acid as a fluorescent probe. It was found that injecting 3 standard liter per minute (SLPM) of oxygen increased the ·OH yield by 6 times with only 1.2 times increase in power, whereas<0.5 SLPM of oxygen did not improve the ·OH yield due to lower breakdown voltage. Negative polarity voltage increased the breakdown voltage and ·OH yield due to asymmetric density and pressure distribution in the throat tube. This polarity effect was explained by numerical simulation. Using indigo carmine (E132) as a model pollutant, the HCAOP process degraded 20 mg/L of dye in 5 L water within 2 min following a first-order reaction. The lowest electric energy per order (EEO) was 0.26 (kWh/m3/order). The HCAOP process is a highly efficient flow-type advanced oxidation process with potential industrial applications.

Prospective Exploratory Study of the Effects of Postoperative Endocrine Medication on the Endometrium in Breast Cancer Patients.

This study aimed to investigate the pathological effects of long-term postoperative endocrine medication on the endometrium in breast cancer patients. Data of 99 patients with primary breast cancer who underwent hysteroscopy and obtained endometrial biopsy from 1 June 2018 to 31 December 2021 at the Beijing Obstetrics and Gynecology Hospital, Capital Medical University. Beijing Maternal and Child Health Care Hospital were prospectively collected. Hysteroscopy was performed followed by endometrial histopathological examination in 99 breast cancer patients, including 44 taking tamoxifen (TAM), 26 taking other endocrine drugs, and 29 not taking endocrine drugs. The endometrial thickness in the TAM group was significantly higher than that in the other endocrine drug groups and the group not taking endocrine drugs (p=0.017). The receiver operating characteristic curves for the abnormal premenopausal endometrial thickening were plotted in this study; an endometrial thickness of 15.5 mm seen on ultrasound could be used as the most accurate ultrasound diagnostic threshold for the diagnosis of abnormal premenopausal endometrial hyperplasia, with an area under the curve of 0.888 (95% CI: 0.716, 1.000), a sensitivity of 100%, and a specificity of 75%, which was consistent with the results of our previous retrospective study. An endometrial thickness of ≥5 mm in postmenopausal women with breast cancer taking TAM was still used as the cut-off value for routine ultrasound diagnosis of abnormal postmenopausal endometrial hyperplasia. An ultrasound endometrial thickness (proliferative phase) of >15 mm in premenopausal patients can be used as the most accurate ultrasound diagnostic threshold for the diagnosis of abnormal endometrial hyperplasia. After menopause, an ultrasound endometrial thickness of ≥5 mm is still used as the criterion for diagnosing abnormal endometrial hyperplasia. Older patients should be monitored for signs of vaginal bleeding and fluid discharge, and hysteroscopy should be performed if necessary to ascertain the endometrial condition.

Paleoproterozoic alkaline-carbonatite magmatism in the convergent tectonic setting: Evidences from 2.07 Ga Dubravinsky complex in the Eastern Sarmatia

The Dubravinsky alkaline-carbonatite complex (ACC) include two relatively large plutons: the arcuate shape Dubravinka pluton and linear Chernyanka pluton intruding the Paleoarchean TTG of the Kursk block of Sarmatia and consisting of three main lithologies: alkaline pyroxenites, carbonatites (together with silicocarbonatites and phoscorites) and syenites (including alkaline granites). The carbonatites and silicocarbonatites are enriched in trace and rare earth elements, which contents vary significantly.The source for the alkaline pyroxenites and carbonatites could be enriched protoliths from the subcontinental lithospheric mantle, produced by melting and release of fluids from the subducted oceanic slab at c. 2.1 Ga. The primary igneous C and O isotope composition is preserved in the carbonatite: δ13C (‰ VPDB) = (−4.9) - (−6.4), δ18O (‰ VSMOW) = (+8.0) – (+9.8). The alkaline granites display well preserved isotope markers of a long-lasting crustal prehistory indicating Paleoarchean source. The syenites have a lesser contribution of Paleoarchean crustal material.The alkaline pyroxenites and carbonatites are undoubtedly initially igneous rocks that have undergone c. 2.07 Ga-old high-temperature metamorphism. The Dubravinsky ACC is most likely 2.07–2.08 Ga-old, not much older than the metamorphic event. The Dubravinsky ACC has been formed in a suprasubduction setting from both mantle and crustal sources. It is the earliest known carbonatite complex in the World resulted from subduction-collision processes, and the first sign of transition to deep subduction of the modern style.

Formation of authigenic grey monazite: A palaeo-thermal anomaly marker in very-low grade metamorphic rocks?

Reassessment of France’s rare earth element (REE) potential led us to investigate REE behaviour in the black shales of the Middle Ordovician Angers-Traveusot Formation in central Brittany (France). This study focuses on the distribution of nodular grey monazite (up to 200 g/t) within the shales, which formed in response to the diagenetic and low-grade metamorphic evolution of the studied area. Whole rock geochemistry, rock–eval pyrolysis and evolution of clay mineral crystallinity were firstly used to determine temperature and mass transfer conditions in the black shales. Then, monazite texture, composition and U–Pb in-situ dates were determined, and correlated with the diagenetic/anchimetamorphic conditions. Nodular monazite appears in the Ordovician black shales at the transition between high-grade diagenesis and the anchizone metamorphic facies, in response to processes controlled by competing influences such as organic matter maturation, Fe oxide/hydroxide reduction and clay transformation with accompanying fluid release. Monazite occurs mainly as elongated nodules, up to 2 mm in diameter that are characterised by their grey colour caused by an abundance of host-rock mineral inclusions. Monazite nodule compositions are zoned with Nd and middle REE-rich cores surrounded by Ce-rich rims, with no evidence of inherited domains. Ce-monazite also occurs as a replacement of nodular monazite or in late-stage fractures. Zoned nodular grey monazites were dated at ca. 403.6 ± 2.9 Ma, which is proposed to record the high heat flux that led to the anchimetamorphic conditions found at the base of the Angers-Traveusot formation, prior to the Variscan deformation. Crystallisation of the metamorphic Ce-monazite occurred at two periods, dated at 382.6 ± 2.9 Ma and 349.6 ± 6 Ma, which correspond to pre-collisional and collisional tectono-metamorphic stages respectively. Nodular grey monazite constitutes an interesting alternative economic solution because of its very low content in both Th (X¯=2160 ppm) and U (X¯=145 ppm) and negligible radiological impact if mined. However, placers currently display a limited economical interest.

Diffusion-free valve for preprogrammed immunoassay with capillary microfluidics

By manipulating the geometry and surface chemistry of microfluidic channels, capillary-driven microfluidics can move and stop fluids spontaneously without external instrumentation. Furthermore, complex microfluidic circuits can be preprogrammed by synchronizing the capillary pressures and encoding the surface tensions of microfluidic chips. A key component of these systems is the capillary valve. However, the main concern for these valves is the presence of unwanted diffusion during the valve loading and activation steps that can cause cross-contamination. In this study, we design and validate a novel diffusion-free capillary valve: the π-valve. This valve consists of a 3D structure and a void area. The void acts as a spacer between two fluids to avoid direct contact. When the valve is triggered, the air trapped within the void is displaced by pneumatic suction induced from the capillary flow downstream without introducing a gas bubble into the circuit. The proposed design eliminates diffusive mixing before valve activation. Numerical simulation is used to study the function and optimize the dimensions of the π-valve, and 3D printing is used to fabricate either the mould or the microfluidic chip. A comparison with a conventional valve (based on a constriction-expansion valve) demonstrates that the π-valve eliminates possible backflow into the valve and reduces the mixing and diffusion during the loading and trigger steps. As a proof-of-concept, this valve is successfully implemented in a capillary-driven circuit for the determination of benzodiazepine, achieving the successive release of 3 solutions in a 3D-printed microfluidic chip without external instrumentation. The results show a 40% increase in the fluorescence intensity using the π-valve relative to the conventional value. Overall, the π-valve prevents cross-contamination, minimizes sample use, and facilitates a sophisticated preprogrammed release of fluids, offering a promising tool for conducting automated immunoassays applicable at point-of-care testing.

On‐Demand Inkjet Printed Hydrophilic Coatings for Flow Control in 3D‐Printed Microfluidic Devices Embedded with Organic Electrochemical Transistors

AbstractMicrofluidic surface chemistry can enable control of capillary‐driven flow without the need for bulky external instrumentation. A novel pondered nonhomogeneous coating defines regions with different wetting properties on the microchannel walls. It changes the curvature of the liquid–air meniscus at various channel cross‐sections and consequently leads to different capillary pressures, which is favorable in the strive toward automatic flow control. This is accomplished by the deposition of hydrophilic coatings on the surface of multilevel 3D‐printed (3DP) microfluidic devices via inkjet printing, thereby retaining the surface hydrophilicity for at least 6 months of storage. To the best of our knowledge, this is the first demonstration of capillary flow control in 3DP microfluidics enabled by inkjet printing. The method is used to create “stop” and “delay” valves to enable preprogrammed capillary flow for sequential release of fluids. To demonstrate further utilization in point‐of‐care sensing applications, screen printed organic electrochemical transistors are integrated within the microfluidic chips to sense, sequentially and independently from external actions, chloride anions in the (1–100) × 10−3 m range. The results present a cost‐effective fabrication method of compact, yet comprehensive, all‐printed sensing platforms that allow fast ion detection (&lt;60 s), including the capability of automatic delivery of multiple test solutions.

Numerical Analysis of Convective Mass Transfer during Multi-Droplet Impingement on a Structured Surface in the Presence of an Adhered Liquid Film—An Application to Spray Etching of PCBs

Multi-droplet impingement is a fundamental aspect inherent to all kinds of technical spray processes which typically aim at enhancing the convective exchange of reagents or heat at the impinged surface. In this paper, the impingement of multiple droplets onto a structured surface is investigated by a comprehensive CFD model, which resolves the dynamics of the individual droplets and the film on a micro-scale level based on the Volume of Fluid (VOF) method. The considered surface topology includes cavities and is typical for protective masks used in the spray etching of Printed Circuit Boards (PCBs). The agitation of the liquid film in terms of the convective mass transfer rates across virtual horizontal evaluation planes is studied and the influence of film height and droplet impaction velocity is elaborated. Passive tracer tracking is employed to investigate the release and re-entrainment of fluid at the surface cavities. Two modes of mass exchange between the cavities and the main flow upon droplet impingement are identified, which are central inflow accompanied by lateral outflow (1) and lateral inflow with outflow at the opposing side (2). A statistical analysis of the allocation of tracer particles shows that high impaction velocities and low film heights correlate with an enhanced decay of tracer particles within the cavities. The susceptibility to re-entrainment is also reduced by high impaction velocities, whereas increased film heights are found to promote re-entrainment.

Detachment-parallel recharge can explain high discharge fluxes at the TAG hydrothermal field

Submarine massive sulfide deposits on slow-spreading ridges are larger and longer-lived than deposits at fast-spreading ridges, likely due to more pronounced tectonic faulting creating stable preferential fluid pathways. The TAG hydrothermal mound at 26∘N on the Mid-Atlantic Ridge (MAR) is a typical example located on the hanging wall of a detachment fault. It has formed through distinct phases of high-temperature fluid discharge lasting 10s to 100s of years throughout at least the last 50,000 yrs and is one of the largest sulfide accumulations on the MAR. Yet, the mechanisms that control the episodic behavior, keep the fluid pathways intact, and sustain the observed high heat fluxes of possibly up to 1700 MW remain poorly understood. Previous concepts involved long-distance channelized high-temperature fluid upflow along the detachment but that circulation mode is thermodynamically unfavorable and incompatible with TAG's high discharge fluxes. Here, based on the joint interpretation of hydrothermal flow observations and 3-D flow modeling, we show that the TAG system can be explained by episodic magmatic intrusions into the footwall of a highly permeable detachment surface. These intrusions drive episodes of hydrothermal activity with vertical discharge and recharge along the detachment. The numerical simulations reveal that the high-temperature circulation system at TAG may be confined to a vertical zone of enhanced permeability that channelizes upflow and a recharge system that is hosted by the detachment surface with a high permeability of 2×10−13 to 10−12m2. This revised flow regime reconciles problematic aspects of previously inferred circulation patterns and allows to identify the prerequisites for generating substantive seafloor mineral systems.

Focused fluid discharge as subaqueous landsliding factor, an example of Krasnoyarskiy landslide, the Lake Baikal

There are represented results of Krasnoyarskiy subaqueous landslide researches in this paper. Landslide is located at subaqueous part of delta of the Selenga river. A multidisciplinary approach was applied to the study of the landslide, including seismo-acoustic, lithological, gas-geochemical and geotechnical studies. Obtained data from landslide and surrounding soils allowed to put forward a hypothesis, whereby a key factor to landslide origin was been high gas saturation of the soils and reason of landslide was an earthquake. The proposed approach to the studying of bottom soils in lakes and seas can be applied both in assessing their stability and in searching for focus fluid discharging zones at the bottom in areas associated with hydrocarbon deposits in the sedimentary section. Also, approach can be applied in mapping of permafrost melting in Arctic region offshore, where gases are often accumulating below it.

Focused Fluid Discharge as a Subaqueous Landsliding Factor, Based on the Example of the Krasnoyarskiy Landslide, Lake Baikal

Focused Fluid Discharge as a Subaqueous Landsliding Factor, Based on the Example of the Krasnoyarskiy Landslide, Lake Baikal

To Evaluate the Frequencies of Post- Traumatic Cerebrospinal Fluid Leak in Patients Presenting with Traumatic Brain Injury

Introduction: Traumatic brain injury is the fourth largest cause of fatal trauma worldwide. The social and economic implications of traumatic brain injuries are immense whilst the physical and mental bearing upon the patient is devastating. Objective: Objective of this study is to evaluate the frequencies of post- traumatic cerebrospinal fluid leak in patients presenting with traumatic brain injury. Methodology of the study: This study was conducted at Neuro Surgery Department of Lady Reading Hospital, Peshawar during 20/7/2020 to 20/1/2021.In the current study a total of 303 patients presenting with initial head trauma presenting within 24 hours with Glasgow coma score ≤15, patients in age between 18 to 65 years and both gender (male/female) were included in the study. All the patients were subjected for detailed history, clinical examination and radiological examination i.e. CT and MRI was done for the confirmation of brain injury. All the patients were followed till 7th post operative day for the diagnosis of Cerebrospinal fluid leak. It is clear water cerebrospinal fluid discharge diagnosed on clinical examination till 7th post-trauma day and was determined in terms of rhinorrhea or otorrhea. Results: Our study shows that among 303 patients was analyzed as 215(71%) patients were in age range 18-40 years, 88(29%) patients were in age range 41-65 years. 239(79%) patients were male and 64(21%) patients were female. More over 18(6%) patients had CSF leak while 285(94%) patients didn’t had CSF leak. Practical Implication: This study will be useful for finding the post-traumatic cerebrospinal fluid leak. Conclusion: Our study concludes that the frequencies of post-traumatic cerebrospinal fluid leak was 6% in patients presenting with traumatic brain injury. Keywords: Post-traumatic cerebrospinal fluid leak, traumatic brain injury.

Sedimentary deformation relating to episodic seepage in the last 1.2 million years: a multi-scale seismic study from the Vestnesa Ridge, eastern Fram Strait

Seafloor hydrocarbon seepage is a natural fluid release process that occurs worldwide on continental shelves, slopes, and in deep oceanic basins. The Vestnesa sedimentary ridge in the eastern Fram Strait hosts a deep-water gas hydrate system that became charged with hydrocarbons ∼2.7 Ma and has experienced episodic seepage along the entire ridge until a few thousand years ago, when seepage activity apparently ceased in the west but persisted in the east. Although it has been documented that faults and fractures play a key role in feeding the seeps with thermogenic gases, the mechanisms controlling seepage periodicity remain poorly understood. Here we integrate high-resolution P-cable 3D seismic and Chirp data to investigate the spatial and temporal evolution of high-resolution fractures and fluid flow features in the west of the Vestnesa Ridge. We characterize sediment deformation using a fracture density seismic attribute workflow revealing two highly deformed stratigraphic intervals and associated small-scale pockmarks (&amp;lt;20 m diameter). Chronostratigraphic constraints from the region show that these two highly deformed intervals are influenced by at least three major climatic and oceanic events during the last 1.2 million years: the Mid-Pleistocene Transition (∼1.25–0.7 Ma), the penultimate deglaciation (∼130 ka) and the last deglaciation (Heinrich Stadial 1: ∼16 ka). These periods of deformation appear associated with seismic anomalies potentially correlated with buried methane-derived authigenic carbonate and have been sensitive to shifts in the boundary of the free gas-gas hydrate interface. Our results show shifts (up to ∼30 m) in the depth of the base of the gas hydrate stability zone (GHSZ) associated with major changes in ocean bottom water temperatures. This ocean-driven effect on the base of the GHSZ since the Last Glacial Maximum coincides with the already highly deformed Mid-Pleistocene Transition sedimentary interval and likely enhanced deformation and gas leakage along the ridge. Our results have implications for understanding how glacial cycles impact fracture formation and associated seepage activity.

Postoperative three-dimensional endoanal ultrasound findings and relation to anal fistula plug failure

Objectives To explore the utilization of three-dimensional (3D) endoanal ultrasound (EAUS) for the follow-up of the anal fistula plug (AFP), describe morphological findings in postoperative 3D EAUS, and evaluate if postoperative 3D EAUS combined with clinical symptoms can predict AFP failure. Materials and methods A retrospective analysis of 3D EAUS examinations performed during a single-centre study of prospectively included consecutive patients treated with the AFP between May 2006 and October 2009. Postoperative assessment by clinical examination and 3D EAUS was performed at 2 weeks, 3 months and 6–12 months (“late control”). Long-term follow-up was carried out in 2017. The 3D EAUS examinations were blinded and analysed by two observers using a protocol with defined relevant findings for different follow-up time points. Results A total of 95 patients with a total of 151 AFP procedures were included. Long-term follow-up was completed in 90 (95%) patients. Inflammation at 3 months, gas in fistula and visible fistula at 3 months and at late control, were statistically significant 3D EAUS findings for AFP failure. The combination of gas in fistula and clinical finding of fluid discharge through the external fistula opening 3 months postoperatively was statistically significant (p < 0.001) for AFP failure with 91% sensitivity and 79% specificity. The positive predictive value was 91%, while the negative predictive value was 79%. Conclusions 3D EAUS may be utilized for the follow-up of AFP treatment. Postoperative 3D EAUS at 3 months or later, especially if combined with clinical symptoms, can be used to predict long-term AFP failure. ClinicalTrials.gov identifier NCT03961984

Amino Acid-Derived Bacterial Metabolites in the Colorectal Luminal Fluid: Effects on Microbial Communication, Metabolism, Physiology, and Growth.

Undigested dietary and endogenous proteins, as well as unabsorbed amino acids, can move from the terminal part of the ileum into the large intestine, where they meet a dense microbial population. Exfoliated cells and mucus released from the large intestine epithelium also supply nitrogenous material to this microbial population. The bacteria in the large intestine luminal fluid release amino acids from the available proteins, and amino acids are then used for bacterial protein synthesis, energy production, and in other various catabolic pathways. The resulting metabolic intermediaries and end products can then accumulate in the colorectal fluid, and their concentrations appear to depend on different parameters, including microbiota composition and metabolic activity, substrate availability, and the capacity of absorptive colonocytes to absorb these metabolites. The aim of the present review is to present how amino acid-derived bacterial metabolites can affect microbial communication between both commensal and pathogenic microorganisms, as well as their metabolism, physiology, and growth.

Research on stability and control strategies for a spring-loaded valve with bypass outlet

The stability and control strategies of a spring-loaded valve with bypass outlet have been studied by combining numerical and theoretical analysis. First, a nonlinear dynamical model and a CFD model of a spring-loaded valve with bypass outlet are developed. The theoretical analysis requires parameters such as discharge coefficients and fluid forces obtained from CFD simulations. The equivalent area of the fluid forces and discharge coefficients are similar at different pressure differences, leading to a reduced-order formulation that serves the theoretical analysis of nonlinear dynamics. Second, the valve disc oscillates at small constant flow rates by nonlinear dynamical analysis. The oscillation frequency is a superposition of the Helmholtz cavity and the mass spring system, which increases as the valve disc impacts the seat or the upper limiter. More importantly, there is a frequency lock-in phenomenon at small fluctuating flow rates, which vanishes at large flow rates. The oscillations are not symmetric during the opening and closing processes, and the oscillations are more severe during the opening processes. Finally, the bypass outlet has a great effect on the stability of valve disc, which can appropriately kill the nonlinear component in the dynamic equation. A reasonable bypass sleeve design can reduce the unstable flow range and oscillation amplitude. This paper provides a reference for the design of spring-loaded valves.

Discharge timing and origin of fluids at methane seeps in the late Cretaceous subduction zone of Hokkaido, Japan: Coupling U–Pb calcite dating with Sr–Nd isotope analysis

Seepage of methane-rich fluids is common in subduction zones throughout Earth's history. However, the causes and hydrogeological regimes of methane seepage in the geological past are commonly elusive. To provide insights into the hydrogeological regime and structural evolution of the Cretaceous subduction zone of Hokkaido, Japan, this study investigates the timing of discharge and migration pathways of fluids emitted at five ancient methane seeps using U–Pb dating and coupled Sr, Nd, C, and O isotope analyses of the authigenic seep carbonates. The carbonates were collected from forearc-basin sediments of the Yezo Group, which are underlain by a mafic igneous basement (lower Sorachi ophiolite) detached from the subducting plate. The subduction zone is known to have experienced intermittent accretionary and non-accretionary stages, and the U–Pb dates determined for seep carbonates document two fluid discharge events, ∼100 and ∼80 Ma, falling within the accretionary periods. The 87Sr/86Sr ratios (0.70682–0.70781) and εNd values (−5.9 to −0.1) of the carbonates show significant variability, indicating the seeping fluids experienced interactions with the mafic rocks of the lower Sorachi ophiolite and with siliciclastic sediments of the Yezo Group. The δ13C values of the carbonates, as low as −49‰, suggest a primarily microbial origin of the seeping methane, which makes methane migration from the underplating materials at high temperatures (>100 °C) unlikely. These results demonstrate that the episodic expulsion of the methane-rich fluids, originating from within the forearc basin rather than from the underplating materials, occurred during the accretionary stages and played a major role in methane seepage in the Cretaceous subduction system.

Influence of shallow hydrothermal fluid release on the functioning of phytoplankton communities

In the Western Tropical South Pacific (WTSP) Ocean, a hotspot of dinitrogen fixation has been identified. The survival of diazotrophs depends, among others, on the availability of dissolved iron (DFe) largely originating, as recently revealed, from shallow hydrothermal sources located along the Tonga-Kermadec arc that fertilize the Lau Basin with this element. On the opposite, these fluids, released directly close to the photic layer, can introduce numerous trace metals at concentrations that can be toxic to surface communities. Here, we performed an innovative 9-day experiment in 300 L reactors onboard the TONGA expedition, to examine the effects of hydrothermal fluids on natural plankton communities in the WTSP Ocean. Different volumes of fluids were mixed with non-hydrothermally influenced surface waters (mixing ratio from 0 to 14.5%) and the response of the communities was studied by monitoring numerous stocks and fluxes (phytoplankton biomass, community composition, net community production, N2fixation, thiol production, organic carbon and metal concentrations in exported material). Despite an initial toxic effect of hydrothermal fluids on phytoplankton communities, these inputs led to higher net community production and N2fixation rates, as well as elevated export of organic matter relative to control. This fertilizing effect was achieved through detoxification of the environment, rich in potentially toxic elements (e.g., Cu, Cd, Hg), likely by resistantSynechococcusecotypes able to produce strong binding ligands, especially thiols (thioacetamide-like and glutathione-like compounds). The striking increase of thiols quickly after fluid addition likely detoxified the environment, rendering it more favorable for phytoplankton growth. Indeed, phytoplankton groups stressed by the addition of fluids were then able to recover important growth rates, probably favored by the supply of numerous fertilizing trace metals (notably Fe) from hydrothermal fluids and new nitrogen provided by N2fixation. These experimental results are in good agreement within-situobservations, proving the causal link between the supply of hydrothermal fluids emitted at shallow depth into the surface layer and the intense biological productivity largely supported by diazotrophs in the WTSP Ocean. This study highlights the importance of considering shallow hydrothermal systems for a better understanding of the biological carbon pump.

Fracture Propagation Mechanism of Radial Well-Guided Preflush Fluid Acid Fracturing under Injection Discharge Control

In view of the low availability of carbonate reservoirs, a radial well-assisted preflush acid fracturing technology is proposed to help communicate oil and gas reservoirs in non-principal stress directions. The acid fracturing model of the auxiliary preflush in the radial well is established by using the extended finite element and the two-scale continuous model. The mechanism of fracture directional propagation under the control of injection discharge is analyzed, and the deflection coefficient is introduced to characterize the guiding effect quantitatively. The effects of different in-situ stress differences and injection discharge on the guiding effect and guiding mechanism of radial wells are studied emphatically. The results show that the induced stress field caused by radial wells and the high-pressure gradient at the end of fractures are the main reasons for the directional propagation of fractures. Horizontal in-situ stress difference is the main factor, which influences the guiding effect by controlling the induced stress field and pressure gradient. The radial well can effectively guide fracture propagation when the local stress difference is less than 3 MPa. The preflush fluid discharge and acid discharge are important factors affecting the guiding effect. The preflush fluid discharge affects the guiding effect by controlling the induced gravitational field and pressure gradient. The preflush fluid discharge between 2.5-3.5 m3·min-1 is most conducive to the directional expansion of acid fracturing cracks. The acid discharge affects the guiding effect by controlling the pressure gradient: the smaller the acid discharge, the more unfavorable the directional expansion of the acid fracture. Compared with the preflush fluid discharge, the influence of the acid discharge is smaller. The theoretical basis can be used in the field application of radial well-assisted preflush fluid acid fracturing technology through the article.

Validity of Local Thermal Equilibrium Assumption for Heat Transfer in a Saturated Soil Layer

The assumption of local thermal equilibrium (LTE) between solid and fluid phases commonly is used for studies of heat transfer in saturated soil and is valid for a wide range of conditions. However, for certain conditions, the heat transfer process may give rise to local thermal nonequilibrium (LTNE) in which adjacent solid and fluid phases have different temperatures. This note presents the results of a numerical study of the validity of the LTE assumption for one-dimensional heat transfer in a saturated soil layer with fluid flow. For the conditions investigated, the LTE assumption holds for soil with particle sizes smaller than the gravel range. For soil with particles sizes in the gravel range and larger, the LTE assumption may be valid or invalid, depending primarily on fluid discharge velocity, with higher fluid velocity values more likely to produce LTNE conditions.